TWI905373B - Protective film formation film, composite film for protective film formation, and wafer regeneration method - Google Patents

Abstract

This invention relates to a protective film forming membrane, which, when subjected to a tensile test, exhibits a strain of 0.5% or more when the ^initial stress is 0.1 N/mm², and a strain of 200% or less when the initial stress is 0.6 N/ ^mm² . The tensile test involves holding a test piece of the aforementioned protective film forming membrane, which is a plurality of sheets, with two 30 mm intervals between them. The test piece is stretched at a speed of 1000 mm/min in a direction parallel to the surface of the test piece between the two intervals, and the stress generated in the test piece and the strain of the test piece in the tensile direction are measured.

Description

Protective film formation film, composite film for protective film formation, and wafer regeneration method

This invention relates to a protective film forming film, a composite wafer for forming a protective film, and a method for wafer regeneration.

This case is based on the claim for priority made in Japanese Patent Application No. 2021-047597 filed in Japan on March 22, 2021, and the contents of that application are incorporated herein by reference.

A semiconductor wafer or insulator wafer, etc., has a circuit formed on one side (electrical surface), and then has protruding electrodes such as bumps on that side (electrical surface). Such wafers are diced into chips and mounted on a circuit substrate via bonding pads connected to the protruding electrodes.

In such wafers or chips, a protective film is sometimes used to protect the side (inner surface) opposite to the electrical surface to prevent damage such as cracking.

To form such a protective film, a protective film forming film is attached to the inner surface of the wafer. The protective film forming film may be deposited on a support sheet to support it, forming a protective film forming composite, or it may not be deposited on the support sheet (see Patent 1). Next, the wafer with the protective film forming film on its inner surface is processed through various steps to form a chip with a protective film on its inner surface (a chip with a protective film). This chip with a protective film is then picked up and mounted on a circuit board to form various substrate devices (e.g., semiconductor devices).

When the protective film is attached to the inner surface of a wafer, attachment abnormalities may occur, such as misalignment of the protective film attachment position or attachment of the protective film with foreign objects trapped between the inner surface of the wafer and the attachment surface. Wafers with such attachment abnormalities are unsuitable for subsequent steps. Furthermore, discarding wafers with attachment abnormalities would increase the manufacturing cost of the protective film-coated chip and substrate assembly due to the high cost of wafers. Therefore, it would be highly useful if it were feasible to peel off the protective film from the wafer with attachment abnormalities and then reattach a newly prepared protective film to the inner surface of the wafer. This paper discusses a protective film forming film for the purpose of re-attaching this protective film. It involves attaching the film to the inner surface of a wafer and then peeling it off, thus making the inner surface of the wafer regenerable for re-attaching the protective film. Furthermore, a protective film forming film is disclosed in which the surface roughness (Ra) of the attachment surface of the wafer is a certain value or higher (see Patent Document 2).

[Previous Technical Documents] [Patent Documents]

[Patent Document 1] International Publication No. 2015/111632.

[Patent Document 2] International Publication No. 2016/158727.

The thickness of a wafer is typically adjusted for use by grinding its inner surface. This inner surface is initially coarsely ground using a grinding machine, followed by a final grinding process to achieve a smoother finish. However, recently, in an effort to shorten grinding time, the final grinding process has been omitted, resulting in a wafer with a rougher surface.

On this rough, ground surface (inner surface), there are numerous deep and large recesses. When a protective film is applied to the inner surface of this wafer, these recesses need to be fully embedded using the protective film. If this is not done, the adhesion strength between the protective film and the wafer or chip may decrease after the protective film is formed, ultimately reducing the reliability of the resulting substrate assembly. Therefore, to avoid this problem, when applying the protective film to the rough inner surface of the wafer, the temperature and pressure during application are increased higher than usual, and the application speed is slowed down, ensuring that the recesses are fully embedded using the protective film.

However, this can lead to adhesion abnormalities when the protective film is applied. Because the protective film is fully embedded in the recess, peeling it from the wafer becomes difficult, and sometimes re-application becomes challenging. Therefore, the protective film forms disclosed in Patents 1 and 2 are not intended to solve this problem.

The purpose of this invention is to provide a protective film forming film, a protective film forming composite having the aforementioned protective film forming film, and a method for regenerating a wafer using the aforementioned protective film forming film or protective film forming composite. The aforementioned protective film forming film is used to form a protective film on the inner surface of a wafer. The protective film forming film is applied to the inner surface of the wafer before it is diced into wafers. Furthermore, for the purpose of re-attaching, when the protective film forming film is peeled off from the inner surface of the wafer, it can be easily peeled off even if the inner surface of the wafer is rough, thus regenerating the inner surface of the wafer into a state where a protective film forming film can be reattached.

The present invention provides a protective film forming film that has undergone a tensile test (a test piece of the aforementioned protective film forming film, which is a plurality of sheets, is held with a 30 mm interval between two points, and the test piece is stretched at a speed of 1000 mm/min in a direction parallel to the surface of the test piece between the two points, and the stress generated in the test piece and the strain of the test piece in the tensile direction are measured). When the stress initially becomes 0.1 N/ ^mm² , the strain is 0.5% or more, and when the stress initially becomes 0.6 N/ ^mm² , the strain is 200% or less.

The protective film formed by this invention can also withstand the aforementioned tensile test, up to 350% of the required tensile strength, without the test piece breaking.

The protective film formed by this invention can also be hardened.

The protective film formed by this invention can also be thermosetting.

This invention provides a composite sheet for forming a protective film, comprising: a support sheet and a protective film forming film disposed on one side of the support sheet; the protective film forming film is the protective film forming film of this invention.

Furthermore, this invention provides a wafer regeneration method, which involves attaching the protective film forming film of this invention, or the protective film forming composite of this invention, to the inner surface of a wafer, and then peeling the protective film forming film off the inner surface of the wafer, thereby making the inner surface of the wafer ready for reattaching the protective film forming film, thus regenerating the wafer.

According to the present invention, a protective film forming film, a protective film forming composite having the aforementioned protective film forming film, and a method for regenerating a wafer using the aforementioned protective film forming film or protective film forming composite are provided. The aforementioned protective film forming film is used to form a protective film on the inner surface of a wafer. The protective film forming film is attached to the inner surface of the wafer before it is diced into wafers. Then, for the purpose of re-attaching, when the protective film forming film is peeled off from the inner surface of the wafer, it can be easily peeled off even if the inner surface of the wafer is rough, thus regenerating the inner surface of the wafer into a state where a protective film forming film can be reattached.

10,20: Support tablets

10a, 20a: One side of the support plate (side 1)

11: Substrate

11a: One side of the substrate (side 1)

12: Adhesive layer

12a: One side of the adhesive layer (side 1)

13,23: Protective film formation

13a, 23a: Surfaces on one side of the protective film (surface 1)

13b, 23b: The protective film forms on the other side of the membrane (the second side).

15: Desquamation

151: First membrane exfoliation

152: Second exfoliation membrane

16: Adhesive layer for jigs

16a: One side of the adhesive layer for the jig (side 1)

101, 102, 103, 104: Composite sheets for forming protective films

401: Laminated Composite Film

501:Laminated film

6: Adhesive tape

9: Wafer

9b: Inner surface of the wafer

[Figure 1] is a schematic cross-sectional view illustrating an example of a protective film forming membrane according to an embodiment of the present invention.

[Figure 2] is a cross-sectional view schematically illustrating an example of a composite sheet for forming a protective film according to an embodiment of the present invention.

[Figure 3] is a cross-sectional view schematically illustrating another example of a composite sheet for forming a protective film according to an embodiment of the present invention.

[Figure 4] is a cross-sectional view schematically illustrating yet another example of a composite sheet for forming a protective film, representing one embodiment of the present invention.

[Figure 5] is a cross-sectional view schematically illustrating yet another example of a composite sheet for forming a protective film, representing one embodiment of the present invention.

[Figure 6A] is a cross-sectional view illustrating one embodiment of the present invention: a wafer regeneration method and a protective film re-attachment method.

[Figure 6B] is a cross-sectional view illustrating one embodiment of the present invention: a wafer regeneration method and a protective film re-attachment method.

[Figure 6C] is a cross-sectional view illustrating one embodiment of the present invention: a wafer regeneration method and a protective film re-attachment method.

[Figure 6D] is a cross-sectional view illustrating one embodiment of the present invention: a wafer regeneration method and a protective film re-attachment method.

[Figure 6E] is a cross-sectional view illustrating one embodiment of the present invention: a wafer regeneration method and a protective film re-attachment method.

[Figure 7A] is a cross-sectional view illustrating another example of a wafer regeneration method and an example of a protective film re-attachment method, representing one embodiment of the present invention.

[Figure 7B] is a cross-sectional view illustrating another example of a wafer regeneration method and an example of a protective film re-attachment method, representing one embodiment of the present invention.

[Figure 7C] is a cross-sectional view illustrating another example of a wafer regeneration method and an example of a protective film re-attachment method, representing one embodiment of the present invention.

[Figure 7D] is a cross-sectional view illustrating another example of a wafer regeneration method and an example of a protective film re-attachment method, representing one embodiment of the present invention.

◇Protective film formation

One embodiment of the present invention is a protective film forming film used to protect a wafer by applying a protective film to it. A tensile test was performed (a stack of the aforementioned protective film forming film, consisting of multiple sheets, was held with two 30mm intervals between its segments. Between these two segments, the test sheets were stretched at a speed of 1000mm/min in a direction parallel to the surface of the test sheets. The stress generated in the test sheets and the strain of the test sheets in the tensile direction were measured). When the stress initially reached 0.1 N/ ^mm² , the strain (sometimes referred to as "strain (0.1 N/ ^mm² )" in this specification) was 0.5% or more. When the stress initially reached 0.6 N/ ^mm² , the strain (sometimes referred to as "strain (0.6 N/mm² ⁾ " in this specification) was also measured. The percentage is below 200%.

The protective film forming film of this embodiment, as described later, can form a composite sheet for forming a protective film by laminating it with a support sheet.

By using the protective film forming film of this embodiment, or by using a protective film forming composite sheet having the protective film forming film, it is possible to manufacture a wafer having a protective film disposed on the inner surface of the wafer.

The aforementioned wafer with a protective film can be manufactured, for example, by: attaching a protective film to the inner surface of the wafer to form a protective film, then allowing the protective film to harden to form a protective film; dividing the wafer into wafers; and finally cutting the protective film along the outer perimeter of the wafers.

This specification may use examples of semiconductor wafers made of elemental semiconductors such as silicon, germanium, and selenium, or compound semiconductors such as GaAs, GaP, InP, CdTe, ZnSe, and SiC, as well as insulating wafers made of insulators such as sapphire, glass, lithium niobate, and lithium tantalum as examples of "wafers".

A circuit is formed on one side of these wafers; in this specification, this side of the wafer with the circuit formed is referred to as the "electrical surface." Then, the side of the wafer opposite to the electrical surface is referred to as the "inner surface."

Wafers are diced into chips using methods such as dicing. In this specification, similar to the case of wafers, the side of the chip where the electrical circuits are formed is called the "surface," and the side of the chip opposite to the surface is called the "inner surface."

Both the electrode surfaces on the wafer and the electrode surface on the chip preferably have protruding electrodes such as bumps or pillars. These protruding electrodes are preferably made of solder.

Furthermore, by using the aforementioned chip with a protective film, a substrate device can be manufactured.

In this specification, the term "substrate device" refers to a substrate device consisting of a chip with a protective film, which is die-connected to a circuit substrate using protruding electrodes on the electrical surface, and then to a bonding pad. For example, whenever a semiconductor wafer is used as the wafer, a semiconductor device can be cited as a substrate device.

On the rough inner surface (grinding surface) of a wafer, there are numerous deep and large recesses. When a protective film is applied to this inner surface, it is necessary to fully embed these recesses using the protective film. By applying the film in this way, a high adhesion strength can be maintained between the protective film and the wafer or chip after the protective film is formed, ultimately resulting in higher reliability of the substrate device.

On the other hand, when the protective film is attached to the inner surface of the wafer, attachment errors may occur. Wafers with such attachment errors are unsuitable for direct use, but discarding them would increase the manufacturing cost of the protective film-coated wafer and substrate assembly due to the high cost of wafers. Therefore, it is desirable to perform a re-attachment process, peeling off the protective film from the wafer with the attachment error and reattaching the protective film to the inner surface of the wafer.

However, when a protective film is typically attached to the rough inner surface of the wafer, and this protective film is fully embedded in the recesses of the aforementioned inner surface, peeling the protective film from the wafer becomes difficult, and sometimes reattaching the protective film becomes challenging.

In contrast, when the protective film of this embodiment is peeled off from the inner surface of the wafer for re-attachment purposes after being attached to the inner surface, it exhibits the aforementioned strain characteristics, allowing for normal and easy peeling even on a rough inner surface. Therefore, by making the inner surface of the wafer suitable for re-attachment of the protective film, the protective film of this embodiment enables wafer regeneration. In this specification, this wafer regeneration capability of the protective film is sometimes referred to as "wafer regeneration adaptability."

In this field, the "recycling" of wafers is sometimes referred to as "rework."

The protective film formed in this embodiment can function as a protective film either through curing or in an uncured state. When the aforementioned protective film forms in an uncured state, for example, during the stage of attachment to the target area on the wafer, it is considered that a protective film has been formed.

The protective film in this embodiment can be either hardened or non-hardened.

The protective film formed by the curing property of this embodiment can be either thermosetting or energy-curing, or it can possess characteristics of both thermosetting and energy-curing properties.

The protective film in this embodiment can also be non-energy-line hardening.

In this manual, the term "energy line" refers to an energy line containing energy quanta within electromagnetic waves or beams of charged particles. Examples of such energy lines include ultraviolet rays, radiation, and electron beams. Ultraviolet rays can be emitted by irradiation using high-pressure mercury lamps, fusion lamps, xenon lamps, black lights, or LED (Light Emitting Diode) lamps. Electron beams are generated by irradiation using electron beam accelerators or similar devices.

In this manual, "energy line hardening property" refers to the property of hardening by exposure to energy lines, while "non-energy line hardening property" refers to the property of not hardening even when exposed to energy lines.

In this instruction manual, "non-hardening" means that it will not harden regardless of whether it is heated or exposed to energy rays.

In the case of forming a protective film by thermosetting the aforementioned protective film, unlike the case of curing by irradiation, the protective film, even with increased thickness, will still fully harden upon heating, thus enabling the formation of a protective film with high protective performance. Furthermore, multiple protective films can be thermoset simultaneously using conventional heating methods such as heating ovens.

In the case where a protective film is formed by curing it through irradiation energy, unlike the case of heat curing, the aforementioned composite sheet for forming protective films does not need to be heat-resistant, allowing for the formation of a wide range of protective film composite sheets. Furthermore, curing can be achieved in a short time through irradiation energy.

When the protective film is used as a protective film without undergoing film curing, the curing step can be omitted, allowing for the manufacture of wafers with a simplified process.

Regarding the ability to form a protective film with higher protective performance, the aforementioned protective film forming film is preferably curable, and more preferably thermosetting.

The protective film can consist of a single layer (monolayer) or multiple layers (two or more). When the protective film consists of multiple layers, these layers can be identical or different, and there are no particular limitations on their combination.

In this specification, not limited to the formation of a protective film, the phrase "multiple layers may be the same or different from each other" means "all layers may be the same, all layers may be different, or only some layers may be the same," and the phrase "multiple layers are different from each other" means "at least one of the constituent materials and thicknesses of each layer is different from each other."

The aforementioned tensile test is conducted by laminating multiple sheets of the aforementioned protective film to create a laminate, which is then used as a test piece. More specifically, the test piece is held with two 30mm intervals between its points, and stretched at a speed of 1000mm/min in a direction parallel to the surface of the test piece (the outermost exposed surface) between these two points. The stress generated in the test piece and the strain of the test piece in the tensile direction (connecting the two points) are measured.

The test piece is maintained with two 30mm intervals between removals. This means that when performing a tensile test, the length of the elongated portion of the test piece in the tensile direction before the test is 30mm; this length is the length of the portion of the test piece subject to the tensile test.

As described above, when the test piece is held at two 30mm intervals, with the length of the test piece in the tensile direction as the reference, and the elongation of the test piece after stretching is ΔL mm, the aforementioned strain of the test piece can be calculated using the following formula: Strain of test piece (%) = ΔL (mm) / 30 (mm) × 100.

The thickness of the aforementioned test piece (laminate) is not particularly limited as long as it does not hinder the implementation of the aforementioned tensile test and does not impair the accuracy of the aforementioned stress and strain measurements.

Typically, the thickness of the aforementioned test piece is preferably 190 μm to 210 μm , more preferably 195 μm to 205 μm , and even more preferably 200 μm .

In this instruction manual, "thickness" is not limited to the aforementioned test piece. Unless otherwise stated, it means the average thickness measured at five randomly selected locations on the object, obtainable according to JIS K7130 using a constant pressure thickness gauge.

The aforementioned test piece can be held at the aforementioned two locations using methods such as known grippers.

There is no particular limitation on the number of protective films forming the aforementioned test piece, as long as there are two or more such films; the number can be arbitrarily selected based on the thickness of each protective film.

For example, when preparing a test piece with a thickness of 200 μm , it is easier to prepare the test piece by using a protective film forming membrane of 5 sheets with a thickness of 40 μm . However, this is just one example, and the number and thickness of the protective film forming membrane used are not limited to this.

The width of the aforementioned test piece (the length relative to the direction orthogonal to the direction connecting the two points mentioned above) is not particularly limited, as long as it does not impair the accuracy of the tensile test; for example, it can be 10mm to 20mm, preferably 15mm.

In this invention, the phrase "when the aforementioned stress initially becomes 0.1 N/ ^mm² " means that during the tensile test described above, the aforementioned stress gradually increases from the start of the test until it initially reaches 0.1 N/ ^mm² . Therefore, even if the test piece exhibits yielding after the tensile test, reducing the aforementioned stress to 0.1 N/ ^mm² , this is still not equivalent to "when the aforementioned stress initially becomes 0.1 N/ ^mm² ". The same applies to "when the aforementioned stress initially becomes 0.6 N/ ^mm² ".

The aforementioned strain (0.1 N/ ^mm² ) is 0.5% or more, for example, it can be any one of 0.7% or more, 1% or more, 1.3% or more, 1.7% or more, and 2% or more. With the strain (0.1 N/ ^mm² ) above the aforementioned lower limit, even in the case of wafer inner surface roughness, the protective film is peeled off normally and easily during the initial stage of peeling the protective film from the wafer inner surface. For example, in this initial stage, excessive external force is not applied to the wafer, and wafer damage is suppressed. More specifically, even when the inner surface of the wafer is rough, and a protective film is embedded in a deep and large recess on that inner surface, during the initial stage of peeling the protective film from the inner surface of the wafer, it is still possible to deform the protective film with a small force while simultaneously creating a starting point for pulling it out of the recess. This allows the protective film to begin peeling from the inner surface of the wafer normally and easily. Conversely, when the protective film is difficult to deform, it is difficult to create a starting point for pulling it out of the recess. Furthermore, because the strain (0.1 N/ ^mm² ) is above the aforementioned lower limit, the undesirable release of the wafer's fixed state (e.g., the state of being adsorbed and fixed under vacuum conditions) is suppressed. Furthermore, the peeling tape, which is attached to the protective film forming membrane for peeling off the protective film forming membrane, is not designed to peel off from the protective film forming membrane, and this is suppressed.

There is no particular upper limit to the aforementioned strain (0.1 N/ ^mm² ). For example, in the initial stage of peeling the protective film from the inner surface of the wafer, the aforementioned strain (0.1 N/ ^mm² ) is preferably less than 3% in terms of making the protective film easier to peel off.

The aforementioned strain (0.1 N/ ^mm² ) can be appropriately adjusted within a range set by any combination of the lower and upper limits described above. For example, in one embodiment, the strain (0.1 N/ ^mm² ) can be any one of 0.5% to 3%, 0.7% to 3%, 1% to 3%, 1.3% to 3%, 1.7% to 3%, and 2% to 3%. However, these are just examples of strain (0.1 N/ ^mm² ).

The aforementioned strain (0.6 N/ ^mm² ) is 200% or less, and can also be any one of 100% or less, 20% or less, 10% or less, 7% or less, or 5% or less. Because the strain (0.6 N/ ^mm² ) is below the aforementioned upper limit, even in the case of a rough inner surface of the wafer, the protective film can be peeled off normally and easily in the later stage of peeling the protective film from the inner surface of the wafer. For example, in this later stage, cohesion breakdown of the protective film is suppressed, and the residue of the protective film on the inner surface of the wafer is suppressed. More specifically, even when the inner surface of the wafer is rough, and a protective film is embedded in a deep and large recess on that inner surface, in the initial stage of peeling the protective film from the inner surface of the wafer, as described above, even if the protective film deforms in a way that initiates its removal from the recess, in the later stage of peeling the protective film from the inner surface of the wafer, the continued deformation of the protective film can still be suppressed. Therefore, the protective film can begin to peel off from the inner surface of the wafer normally and easily. Conversely, if the continued deformation of the protective film cannot be suppressed (the deformation will continue), a portion of the continuously deformed protective film is likely to remain on the inner surface of the wafer.

The lower limit of the aforementioned strain (0.6 N/ ^mm² ) is not particularly limited. For example, in the later stage of peeling the protective film from the inner surface of the wafer, the aforementioned strain (0.6 N/ ^mm² ) is preferably 1% or more in terms of making the protective film easier to peel off.

The aforementioned strain (0.6 N/ ^mm² ) can be appropriately adjusted within a range set by any combination of the aforementioned lower limit and any of the upper limits. For example, in one embodiment, the strain (0.6 N/ ^mm² ) can be any of 1% to 200%, 1% to 100%, 1% to 20%, 1% to 10%, 1% to 7%, and 1% to 5%. However, these are just examples of strain (0.6 N/ ^mm² ).

With the aforementioned strain (0.1 N/ ^mm² ) being 0.5% or more and the aforementioned strain (0.6 N/ ^mm² ) being 200% or less, even in cases where the inner surface of the wafer is rough, the protective film is peeled off normally and easily in both the initial and later stages of the peeling process. Therefore, the protective film exhibits superior wafer regeneration adaptability.

The aforementioned protective film preferably exhibits both the strain range of 0.1 N/ ^mm² and the strain range of 0.6 N/ ^mm² .

However, in the aforementioned protective film, the aforementioned strain (0.6 N/ ^mm² ) is greater than the aforementioned strain (0.1 N/ ^mm² ).

Both the aforementioned strain (0.1 N/ ^mm² ) and the aforementioned strain (0.6 N/ ^mm² ) can be adjusted by regulating the type and content of the components contained in the aforementioned protective film.

For example, when a thermosetting protective film contains the polymer component (A) described later, the strain (0.1 N/ ^mm² ) and strain (0.6 N/ ^mm² ) can be more easily adjusted by adjusting the type and amount of the constituent units of the polymer component (A). More specifically, for example, by using an acrylic resin having a certain amount or more of the constituent units (derived from alkyl methacrylates described later, wherein the alkyl group constituting the alkyl ester has 6 or more carbon atoms and the aforementioned alkyl group has a chain structure) as the polymer component (A), and adjusting the content of the polymer component (A), the strain (0.1 N/ ^mm² ) and strain (0.6 N/ ^mm² ) can be more easily adjusted. Furthermore, an acrylic resin containing a certain amount of constituent units derived from acrylonitrile (described later) is used as polymer component (A), and the content of polymer component (A) is adjusted, thereby making it easier to adjust the strain (0.1 N/mm ² ) and strain (0.6 N/mm ² ).

Furthermore, for example, in the case where the energy-curable protective film forming film contains a polymer (a1) with a weight average molecular weight of 80,000 to 2,000,000 having the energy-curable group described later, or contains a polymer (b) without the energy-curable group, similar to the case where the thermosetting protective film forming film contains a polymer component (A), by adjusting the type and content of these polymer components (the aforementioned polymer (a1) or the aforementioned polymer (b)), the aforementioned strain (0.1 N/ ^mm² ) and the aforementioned strain (0.6 N/ ^mm² ) can be adjusted.

Furthermore, for example, in the case where the non-curing protective film contains the thermoplastic resin described later, similar to the case where the thermosetting protective film contains the polymer component (A), the aforementioned strain (0.1 N/ ^mm² ) and the aforementioned strain (0.6 N/ ^mm² ) can be adjusted by adjusting the type and content of the thermoplastic resin.

Preferably, the protective film formed in the aforementioned tensile test does not break the test piece until the strain reaches 350% (within the range of strain exceeding 0% but below 350%). This type of protective film formation exhibits superior wafer regeneration adaptability.

The surface roughness (Ra) of any one or both sides of the aforementioned protective film is not particularly limited, but preferably less than 300 nm, more preferably less than 100 nm, and for example, it can also be any one of less than 50 nm, less than 40 nm, and less than 38 nm. By attaching the protective film with this surface roughness (Ra) to the inner surface of the wafer, even if the inner surface of the wafer is rough, the protective film can still be used to embed more deeply into the aforementioned recesses. As a result, after the protective film is formed, a higher adhesion strength can be maintained between the protective film and the wafer or chip. Furthermore, the wafer's remanufacturability is not compromised.

There is no particular limitation on the lower limit of the surface roughness (Ra) of any one or both sides of the aforementioned protective film. For example, a protective film with a surface roughness (Ra) of 20 nm or higher on any one or both sides is easier to form.

In this specification, surface roughness (Ra) refers to the arithmetic mean roughness calculated according to ANSI/ASME B46.1.

The aforementioned surface roughness (Ra) of the protective film can be adjusted, for example, by adjusting the formation conditions or surface treatment conditions of the protective film. For instance, by coating the protective film forming composition (described later) onto the object surface of the protective film and drying it as needed, the surface roughness (Ra) of the protective film can be adjusted during the formation of the protective film by regulating the surface condition, such as the surface roughness (Ra) of the object surface.

The thickness of the protective film is preferably between 1 μm and 100 μm , but can also be any one of 3 μm to 80 μm , 5 μm to 60 μm , and 7 μm to 45 μm . By ensuring the thickness of the protective film is above the aforementioned lower limit, a protective film with higher protective performance can be formed. By ensuring the thickness of the protective film is below the aforementioned upper limit, excessive thickness can be avoided.

Here, "thickness of the protective film forming membrane" refers to the overall thickness of the protective film forming membrane. For example, the thickness of a protective film forming membrane composed of multiple layers refers to the total thickness of all the layers constituting the protective film forming membrane.

[Components for forming protective films]

The aforementioned protective film forming film can be formed using a protective film forming composition containing the aforementioned protective film forming film constituent materials. For example, the protective film forming film can be formed by coating the protective film forming composition onto the object surface of the aforementioned protective film forming film and drying it as needed. The ratio of the components in the protective film forming composition that do not vaporize at room temperature is generally the same as the ratio of the aforementioned components in the protective film forming film. In this specification, "room temperature" means a temperature that is neither particularly cold nor particularly hot, that is, a normal temperature, such as a temperature of 15°C to 25°C.

Thermosetting protective film forming films can be formed using thermosetting protective film forming components, energy line curing protective film forming films can be formed using energy line curing protective film forming components, and non-curing protective film forming films can be formed using non-curing protective film forming components.

In this specification, when the protective film forming film possesses both thermosetting and energy-curing properties, for the formation of the protective film, if the contribution of the protective film forming film to thermosetting is greater than its contribution to energy-curing, the protective film forming film is considered a thermosetting material. Conversely, for the formation of the protective film, if the contribution of the protective film forming film to energy-curing is greater than its contribution to thermosetting, the protective film forming film is considered an energy-curing material.

In the protective film forming membrane, the aggregate content of one or more of the components described below in the description of the following ingredients in the protective film forming membrane does not exceed 100% by mass relative to the total mass of the protective film forming membrane.

Similarly, in the protective film forming composition, the total content of one or more of the following ingredients described below in the protective film forming composition, relative to the total mass of the protective film forming composition, does not exceed 100% by mass.

The coating of the protective film forming component can be carried out using known methods, such as the use of various coating machines including: air knife coating machine, doctor blade coating machine, rod coating machine, gravure coating machine, roller coating machine, roller knife coating machine, curtain coating machine, mold coating machine, knife coating machine, screen coating machine, Meyer rod coating machine, and touch coating machine.

Regardless of whether the protective film forming film is curable or non-curable, and furthermore, in the case of curable film, regardless of whether it is thermosetting or energy-line curable, the drying conditions of the protective film forming composition are not particularly limited. However, when the protective film forming composition contains the solvent described later, it is preferable to heat-dry it. Furthermore, protective film forming compositions containing solvent are preferably heat-dried, for example, at 70°C to 130°C for 10 seconds to 5 minutes. However, thermosetting protective film forming compositions are preferably heat-dried in a manner that prevents the composition itself and the thermosetting protective film formed by the composition from thermosetting from heat-drying.

The following sections will explain thermosetting protective film formation, energy line curing protective film formation, and non-curing protective film formation in sequence.

◎Thermosetting protective film formation

When a thermosetting protective film is attached to the target area of a wafer and thermosetting to form the protective film, the curing conditions are not particularly limited, as long as the degree of curing is sufficient to allow the protective film to fully perform its function. The appropriate curing degree should be selected based on the type of thermosetting protective film.

For example, the heating temperature for heat curing the thermosetting protective film is preferably between 100°C and 200°C, but can also be any one of 110°C to 180°C and 120°C to 170°C. The heating time for the aforementioned heat curing is preferably between 0.5 hours and 5 hours, but can also be any one of 0.5 hours to 3 hours and 1 hour to 2 hours.

By heating a protective film formed at room temperature to a temperature exceeding room temperature and then cooling it back to room temperature, the hardness of the heated and cooled protective film is compared with that of the unheated protective film at the same temperature. If the heated and cooled protective film is relatively harder, then the protective film is thermosetting.

As a preferred thermosetting protective film forming film, an example is a thermosetting protective film forming film containing a polymer component (A) and a thermosetting component (B). The polymer component (A) is a component formed by the polymerization reaction of a polymeric compound. The thermosetting component (B) is a component that can undergo a curing (polymerization) reaction by using heat as a trigger. Furthermore, this specification also includes polycondensation reactions in relation to polymerization reactions.

[Component for forming thermosetting protective films (III)]

As a preferred composition for forming a thermosetting protective film, examples include composition (III) for forming a thermosetting protective film containing the aforementioned polymer component (A) and thermosetting component (B) (in this specification, it is sometimes simply referred to as "composition (III)").

[Polymer Component (A)]

Polymer component (A) is a polymer compound used to impart film-forming properties or flexibility to the thermosetting protective film. Furthermore, this specification also includes products of polymerization condensation reactions in relation to the polymer compound.

The polymer component (A) contained in component (III) and the thermosetting protective film can be only one type or two or more types. When there are two or more types, the combination and ratio of those polymer components (A) can be arbitrarily selected.

Examples of polymer components (A) include: acrylic resins, carbamate resins, phenoxy resins, polysiloxane resins, saturated polyester resins, etc., with acrylic resins being preferred.

The aforementioned acrylic resin, which is a component of polymer (A), can be exemplified by well-known acrylic polymers.

The weight-average molecular weight (Mw) of the acrylic resin is preferably between 10,000 and 2,000,000, more preferably between 100,000 and 1,500,000, further preferably between 200,000 and 1,200,000, and particularly preferably between 300,000 and 1,000,000. By having the weight-average molecular weight of the acrylic resin above the aforementioned lower limit, the morphological stability (time-dependent stability during storage) of the thermosetting protective film is improved. Furthermore, it becomes easier to adjust the aforementioned strain (0.6 N/ ^mm² ) to an appropriate range. On the other hand, by having the weight-average molecular weight of the acrylic resin below the aforementioned upper limit, the thermosetting protective film becomes easier to follow the uneven surfaces of the substrate (e.g., the rough inner surface of a wafer). Furthermore, it becomes easier to adjust the aforementioned strain (0.1 N/ ^mm² ) to the appropriate range.

In this instruction manual, the term "weight-average molecular weight," unless otherwise specified, refers to the converted value of polystyrene determined by gel permeation chromatography (GPC).

The glass transition temperature (Tg) of the acrylic resin is preferably -60°C to 70°C, more preferably -50°C to 50°C, further preferably -50°C to 20°C, and particularly preferably -50°C to -5°C. When the Tg of the acrylic resin is above the aforementioned lower limit, for example, the adhesion between the cured protective film and the support sheet is suppressed, and the peelability of the support sheet is appropriately improved. Furthermore, it becomes easier to adjust the aforementioned strain (0.6 N/ ^mm² ) to an appropriate range. On the other hand, when the Tg of the acrylic resin is below the aforementioned upper limit, the adhesion between the thermosetting protective film and the cured protective film and the substrate is improved. Furthermore, it becomes easier to adjust the aforementioned strain (0.1 N/ ^mm² ) to an appropriate range.

When an acrylic resin has m types of constituent units (m being an integer greater than or equal to 2), and each of the m types of monomers from which these constituent units are derived is sequentially assigned a unique number from 1 to m and named "monomer m", the glass transition temperature (Tg) of the acrylic resin can be calculated using the following Fox equation.

(In the formula, Tg is the glass transition temperature of acrylic resin; m is an integer greater than or equal to 2; _Tgk is the glass transition temperature of the homopolymer of monomer m; _Wk is the mass fraction of the constituent unit m derived from monomer m in acrylic resin, where _Wk satisfies the following formula.)

(In the formula, m and _Wk are the same as before.)

The aforementioned Tg _k values can be found in polymer data manuals, adhesive manuals, or polymer handbooks. For example, the Tg _k of methyl acrylate homopolymer is 10°C, the Tg _k of methyl methacrylate homopolymer is 105°C, the Tg _k of 2-hydroxyethyl acrylate homopolymer is -15°C, the Tg _k of glycidyl methacrylate homopolymer is 41°C, the Tg _k of 2-ethylhexyl acrylate homopolymer is -70°C, the Tg _k of acrylic acid homopolymer is 103°C, and the Tg _k of acrylonitrile homopolymer is 97°C.

Examples of acrylic resins include: polymers of one or more (meth)acrylates; copolymers of two or more monomers selected from (meth)acrylic acid, icosinic acid, vinyl acetate, acrylonitrile, styrene, and N-hydroxymethylacrylamide.

Examples of (meth)acrylates that constitute acrylic resins include: methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, dibutyl (meth)acrylate, tributyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, and so on. Octyl acrylate, nonyl acrylate, isononyl acrylate, decyl acrylate, undecyl acrylate, lauryl acrylate, tridecyl acrylate, myristyl acrylate, pentadecyl acrylate, palmitate acrylate, heptadecanyl acrylate, methacrylate Alkyl methacrylates, such as octadecyl methacrylate (stearyl methacrylate), are chain esters with alkyl groups having 1 to 18 carbon atoms; cycloalkyl methacrylates, such as isoborneol methacrylate and dicyclopentyl methacrylate; aralkyl methacrylates, such as benzyl methacrylate; cycloalkyl methacrylates, such as dicyclopentenyl methacrylate; cycloalkyl methacrylates, such as dicyclopentenoxyethyl methacrylate; and cycloalkyl methacrylates, such as dicyclopentenoxyethyl methacrylate. Acrylamide; (meth)acrylates containing glycidyl groups, such as glycidyl methacrylate; (meth)acrylates containing hydroxyl groups, such as hydroxymethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 3-hydroxybutyl methacrylate, and 4-hydroxybutyl methacrylate; and (meth)acrylates containing substituted amino groups, such as N-methylaminoethyl methacrylate. Here, "substituted amino group" refers to a structural group in which one or two hydrogen atoms of an amino group are replaced by a group other than a hydrogen atom.

In this manual, the term "(meth)acrylic acid" encompasses both "acrylic acid" and "methacrylic acid." The same applies to similar terms; for example, "(meth)acrylyl" encompasses both "acrylyl" and "methacrylyl," and "(meth)acrylate" encompasses both "acrylate" and "methacrylate."

The monomers constituting acrylic resins can be a single type or two or more. When there are two or more types, the combination and ratio of those monomers can be arbitrarily chosen.

Acrylic resins may also possess functional groups such as vinyl, (meth)acrylic, amino, hydroxyl, carboxyl, and isocyanate groups, which are capable of bonding with other compounds. These aforementioned functional groups of acrylic resins can bond with other compounds via a crosslinking agent (F) described later, or they can bond directly with other compounds without the use of a crosslinking agent (F).

As a preferred example of an acrylic resin, one can be described as an acrylic resin having a constituent unit derived from an alkyl (meth)acrylate, wherein the alkyl group of the alkyl ester has 6 or more carbon atoms, the alkyl group has a chain structure, and the amount of the constituent unit derived from the alkyl (meth)acrylate relative to the total amount of the constituent units of the acrylic resin is 50% to 75% by mass.

In the aforementioned acrylic resin, the alkyl group preferably has 6 to 18 carbon atoms, more preferably 7 to 13.

The aforementioned alkyl group can be either linear or branched.

The aforementioned acrylic resin preferably further comprises constituent units derived from hydroxyl-containing (meth)acrylates, and the proportion (content) of the constituent units derived from hydroxyl-containing (meth)acrylates relative to the total amount of constituent units constituting the aforementioned acrylic resin is preferably 7% to 20% by mass.

As another example of a preferred acrylic resin, an acrylic resin having constituent units derived from acrylonitrile is provided, wherein the amount (content) of the aforementioned constituent units derived from acrylonitrile relative to the total amount of constituent units constituting the aforementioned acrylic resin is 15% to 45% by mass.

The aforementioned acrylic resin (an acrylic resin having constituent units derived from acrylonitrile) preferably further has constituent units derived from (meth)acrylate, and the proportion (content) of the aforementioned constituent units derived from (meth)acrylate relative to the total amount of constituent units constituting the aforementioned acrylic resin is preferably 65% to 85% by mass.

In this invention, a thermoplastic resin other than acrylic resin (hereinafter sometimes simply referred to as "thermoplastic resin") may be used alone instead of acrylic resin, or it may be used in combination with acrylic resin as a polymer component (A). By using the aforementioned thermoplastic resin, the peelability of the protective film from the support sheet is sometimes improved, or the thermosetting protective film becomes easier to follow the uneven surface of the substrate (e.g., the rough inner surface of a wafer).

The aforementioned thermoplastic resin preferably has a weight-average molecular weight of 1,000 to 100,000, more preferably 3,000 to 80,000.

The glass transition temperature (Tg) of the aforementioned thermoplastic resin is preferably -30°C to 150°C, and more preferably -20°C to 120°C.

Examples of the aforementioned thermoplastic resins include: polyesters, polyurethanes, phenoxy resins, polybutene, polybutadiene, and polystyrene.

The thermoplastic resin contained in component (III) and the thermosetting protective film can be one type or two or more types. When there are two or more types, the combination and ratio of those thermoplastic resins can be arbitrarily selected.

In composition (III), regardless of the type of polymer component (A), the content of polymer component (A) relative to the total content of all components other than the solvent is preferably 10% to 85% by mass, more preferably 15% to 70% by mass, for example, it can also be any one of 15% to 55% by mass, 15% to 40% by mass, or any one of 25% to 70% by mass, or 30% to 60% by mass.

This content is synonymous with the following: Regardless of the type of polymer component (A), the content of polymer component (A) in the thermosetting protective film forming film, relative to the total mass of the thermosetting protective film forming film, is preferably 10% to 85% by mass, more preferably 15% to 70% by mass, for example, it can also be any one of 15% to 55% by mass, and 15% to 40% by mass, or any one of 25% to 70% by mass, and 30% to 60% by mass.

This is based on the fact that during the process of removing the solvent from a resin composition containing a solvent to form a resin film, the amount of components other than the solvent generally does not change; the ratio of the content of components other than the solvent is the same in both the resin composition and the resin film. Therefore, in this specification, the following description is not limited to the case of thermosetting protective film formation; the content of components other than the solvent is only recorded in the resin film in which the solvent has been removed from the resin composition.

Polymer component (A) sometimes also corresponds to thermosetting component (B). In this invention, when composition (III) contains a component that corresponds to both polymer component (A) and thermosetting component (B), composition (III) is considered to contain both polymer component (A) and thermosetting component (B).

[Thermosetting component (B)]

Thermosetting component (B) is used to harden the thermosetting protective film.

The thermosetting component (B) contained in component (III) and the thermosetting protective film can be one type or two or more types. When there are two or more types, the combination and ratio of those thermosetting components (B) can be arbitrarily selected.

Examples of thermosetting components (B) include epoxy thermosetting resins, thermosetting polyimide resins, and unsaturated polyester resins, with epoxy thermosetting resins being preferred.

In this specification, the term "thermosetting polyimide resin" refers to the general term for polyimide precursors and thermosetting polyimides that are formed by thermosetting.

[Epoxy thermosetting resin]

Epoxy thermosetting resins are composed of epoxy resin (B1) and thermosetting agent (B2).

The epoxy thermosetting resin contained in component (III) and the thermosetting protective film can be one type or two or more types. When there are two or more types, the combination and ratio of those epoxy thermosetting resins can be arbitrarily selected.

• Epoxy resin (B1)

As for epoxy resins (B1), known epoxy resins include, for example: multifunctional epoxy resins, biphenyl compounds, bisphenol A diglycidyl ether and its hydroxides, o-cresol phenolic varnish epoxy resins, dicyclopentadiene-type epoxy resins, biphenyl-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and phenyl-skeletal epoxy resins, etc., which are epoxy compounds with two or more functions.

As an epoxy resin (B1), epoxy resins with unsaturated hydrocarbon groups can also be used.

The number-average molecular weight of the epoxy resin (B1) is not particularly limited, but in terms of the curability of the thermosetting protective film, as well as the strength and heat resistance of the protective film, it is preferably 300 to 30,000, more preferably 300 to 10,000, and particularly preferably 300 to 3,000.

The epoxy equivalent of the epoxy resin (B1) is preferably from 100 g/eq to 1000 g/eq, more preferably from 150 g/eq to 950 g/eq.

Epoxy resin (B1) can be used alone or in combination with two or more other types. When using two or more types, the combination and ratio of those epoxy resins (B1) can be arbitrarily selected.

• Heat curing agent (B2)

The thermosetting agent (B2) functions as a curing agent for epoxy resin (B1).

Examples of thermosetting agents (B2) include compounds having two or more functional groups that can react with epoxy groups in one molecule. Examples of these functional groups include phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, carboxyl groups, and groups formed by anhydride conversion of acid groups, preferably phenolic hydroxyl groups, amino groups, or groups formed by anhydride conversion of acid groups, and more preferably phenolic hydroxyl groups or amino groups.

Among thermosetting agents (B2), phenolic curing agents containing phenolic hydroxyl groups include, for example, polyfunctional phenolic resins, biphenol, phenolic varnish-type phenolic resins, dicyclopentadiene-type phenolic resins, and aralkyl-type phenolic resins.

Among thermosetting agents (B2), amine-based curing agents containing amine groups include, for example, dicyandiamide.

Thermosetting agent (B2) can also have unsaturated hydrocarbon groups.

When using a phenolic curing agent as the thermosetting agent (B2), the thermosetting agent (B2) with a high softening point or glass transition temperature is preferable in terms of improving the peelability of the protective film's self-supporting sheet.

In the thermosetting agent (B2), the average molecular weight of the resin components, such as polyfunctional phenolic resins, phenolic varnish-type phenolic resins, dicyclopentadiene-type phenolic resins, and aralkyl-type phenolic resins, is preferably 300 to 30,000, more preferably 400 to 10,000, and particularly preferably 500 to 3,000.

In the thermosetting agent (B2), the molecular weight of non-resin components such as biphenol and dicyandiamide is not particularly limited, but is preferably 60 to 500.

Thermosetting agent (B2) can be used alone or in combination with two or more other agents. When using two or more agents, the combination and ratio of those thermosetting agents (B2) can be arbitrarily selected.

In composition (III) and the thermosetting protective film forming film, the content of the thermosetting agent (B2) is preferably 0.1 to 100 parts by weight, more preferably 0.5 to 50 parts by weight, and for example, any one of 0.5 to 25 parts by weight, 0.5 to 10 parts by weight, and 0.5 to 5 parts by weight. When the aforementioned content of the thermosetting agent (B2) is above the aforementioned lower limit, the curing of the thermosetting protective film forming film becomes easier. When the aforementioned content of the thermosetting agent (B2) is below the aforementioned upper limit, the moisture absorption rate of the thermosetting protective film forming film is reduced, and the reliability of the encapsulation obtained using the protective film forming film is further improved.

In the composition (III) and the thermosetting protective film forming film, relative to 100 parts by mass of the total content of polymer component (A) and thermosetting component (B), the content of thermosetting component (B) (e.g., the total content of epoxy resin (B1) and thermosetting agent (B2)) is preferably 10 to 70 parts by mass, more preferably 20 to 60 parts by mass, further preferably 25 to 50 parts by mass, and particularly preferably 30 to 45 parts by mass. By having the aforementioned content of thermosetting component (B) within such a range, for example, the adhesion between the cured protective film and the support sheet is suppressed, and the peelability of the support sheet is improved.

[Hardening Accelerator (C)]

Component (III) and the thermosetting protective film may also contain a curing accelerator (C). The curing accelerator (C) is a component used to adjust the curing rate of component (III).

Examples of preferred hardening accelerators (C) include: tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles (imidazoles formed by replacing one or more hydrogen atoms with groups other than hydrogen atoms) such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole; organophosphines (phosphines formed by replacing one or more hydrogen atoms with organic groups) such as tributylphosphine, diphenylphosphine, and triphenylphosphine; and tetraphenylboronic salts such as tetraphenylphosphonium tetraphenylboronicate and triphenylphosphine tetraphenylboronicate.

The curing accelerator (C) contained in component (III) and the thermosetting protective film can be one type or two or more types. When there are two or more types, the combination and ratio of those curing accelerators (C) can be arbitrarily selected.

When using a curing accelerator (C), in composition (III) and the thermosetting protective film, the content of the curing accelerator (C) is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 7 parts by mass, relative to 100 parts by mass of the thermosetting component (B). By having the aforementioned content of the curing accelerator (C) above the aforementioned lower limit, the effects of using the curing accelerator (C) can be obtained more significantly. By having the content of the curing accelerator (C) below the aforementioned upper limit, for example, the effect of inhibiting the segregation of highly polar curing accelerator (C) towards the interface with the adherend in the thermosetting protective film under high temperature and high humidity conditions becomes greater. As a result, the reliability of wafers with protective films obtained by using protective film formation is further improved.

[Fill Material (D)]

Component (III) and the thermosetting protective film forming film may also contain filler (D). By including filler (D) in the thermosetting protective film forming film, the coefficient of thermal expansion of both the thermosetting protective film forming film and the protective film becomes easier to adjust. By optimizing this coefficient of thermal expansion for the substrate to which the protective film is formed, the reliability of the chip with the protective film obtained using the protective film forming film is further improved. Furthermore, including filler (D) in the thermosetting protective film forming film can also reduce the moisture absorption rate of the protective film or improve heat dissipation.

The filler (D) can be either organic or inorganic, but is preferably inorganic.

Examples of suitable inorganic fillers include: powders of silicon dioxide, alumina, talc, calcium carbonate, titanium dioxide, iron oxide, silicon carbide, and boron nitride; beads formed by spheroidizing these inorganic fillers; surface-modified versions of these inorganic fillers; single-crystal fibers of these inorganic fillers; and glass fibers.

Among these, the inorganic filler is preferably silicon dioxide or aluminum oxide, with silicon dioxide being more preferred.

The filler (D) contained in component (III) and the thermosetting protective film can be one type or two or more types. When there are two or more types, the combination and ratio of those fillers (D) can be arbitrarily selected.

When using filler (D), the content of filler (D) in the thermosetting protective film is preferably 15% to 70% by mass relative to the total mass of the thermosetting protective film. For example, it can also be any one of 25% to 70%, 35% to 70%, 45% to 70%, 50% to 70%, and 55% to 70%, or any one of 15% to 60% and 15% to 55%. With the aforementioned proportion within this range, it becomes easier to adjust the coefficient of thermal expansion of the thermosetting protective film and the protective film. On the other hand, with the aforementioned proportion above the aforementioned lower limit, it becomes easier to adjust the aforementioned strain (0.6 N/ ^mm² ) to an appropriate range. Furthermore, by keeping the aforementioned ratio below the aforementioned upper limit, it becomes easier to adjust the aforementioned strain (0.1 N/ ^mm² ) to an appropriate range.

[Coupler(E)]

Component (III) and the thermosetting protective film forming film may also contain a coupling agent (E). By using a compound with functional groups capable of reacting with inorganic or organic compounds as the coupling agent (E), the adhesion of the protective film formed by the thermosetting protective film forming film to the substrate can be improved. Furthermore, by using the coupling agent (E), the aforementioned protective film does not suffer damage to its heat resistance and its water resistance is improved.

The coupling agent (E) is preferably a compound having a functional group capable of reacting with the functional groups of the polymer component (A), the thermosetting component (B), etc., and is more preferably a silane coupling agent.

Preferred silane coupling agents include, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxymethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-(2-aminoethylamino)propyltrimethoxysilane. Alkane, 3-(2-aminoethylamino)propylmethyldiethoxysilane, 3-(phenylamino)propyltrimethoxysilane, 3-anilinepropyltrimethoxysilane, 3-ureopropyltriethoxysilane, 3-caprylylpropyltrimethoxysilane, 3-caprylylpropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfide, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, imidazolylsilane, etc.

As a preferred silane coupling agent, oligomeric silane coupling agents having a plurality of alkoxysilane groups in one molecule can also be cited.

The aforementioned oligomeric silane coupling agents are less volatile because they contain multiple alkoxysilane groups per molecule, thus effectively improving durability.

Examples of the aforementioned oligomeric silane coupling agents include: epoxy-containing oligomeric silane coupling agents such as "X-41-1053", "X-41-1059A", "X-41-1056" and "X-40-2651" (all manufactured by Shin-Etsu Chemical Co., Ltd.); and hydroxyl-containing oligomeric silane coupling agents such as "X-41-1818", "X-41-1810" and "X-41-1805" (all manufactured by Shin-Etsu Chemical Co., Ltd.).

The coupling agent (E) contained in component (III) and the thermosetting protective film can be one type or two or more types. When there are two or more types, the combination and ratio of those coupling agents (E) can be arbitrarily selected.

When using a coupling agent (E), in the composition (III) and the thermosetting protective film, relative to 100 parts by mass of the total content of polymer component (A) and thermosetting component (B), the content of coupling agent (E) is preferably 0.03 parts by mass to 10 parts by mass, more preferably 0.05 parts by mass to 5 parts by mass, and particularly preferably 0.1 parts by mass to 2 parts by mass. By using the aforementioned content of coupling agent (E) within this range, the chemical compatibility between the thermosetting protective film and the adherend can be slightly controlled, making it easier to adjust adhesion and peelability. On the other hand, by ensuring the content of coupling agent (E) is above the aforementioned lower limit, the effects of using coupling agent (E), such as improved dispersibility of filler (D) on the resin or improved adhesion between the thermosetting protective film and the substrate, can be more significantly obtained. By ensuring the content of coupling agent (E) is below the aforementioned upper limit, the occurrence of outgassing can be further suppressed.

[Cross-connecting agent (F)]

When using compounds such as acrylic resins possessing functional groups such as vinyl, (meth)acrylic, amino, hydroxyl, carboxyl, and isocyanate groups capable of bonding with other compounds as polymer component (A), composition (III) and the thermosetting protective film forming film may also contain a crosslinking agent (F). The crosslinking agent (F) is a component used to crosslink the aforementioned functional groups in polymer component (A) with other compounds. Through this crosslinking, the adhesion and cohesion of the thermosetting protective film forming film can be adjusted.

Examples of crosslinking agents (F) include: organic polyisocyanates, organic polyimides, metal chelate crosslinking agents (crosslinking agents with a metal chelate structure), and aziridine crosslinking agents (crosslinking agents with an aziridine group).

The crosslinking agent (F) contained in component (III) and the thermosetting protective film can be one type or two or more types. When there are two or more types, the combination and ratio of those crosslinking agents (F) can be arbitrarily selected.

When using a crosslinking agent (F), in composition (III), relative to 100 parts by weight of polymer component (A), the content of crosslinking agent (F) is preferably 0.01 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, and particularly preferably 0.5 to 5 parts by weight. By ensuring the aforementioned content of crosslinking agent (F) is above the aforementioned lower limit, the effects of using crosslinking agent (F) can be more significantly obtained. By ensuring the aforementioned content of crosslinking agent (F) is below the aforementioned upper limit, the excessive use of crosslinking agent (F) can be suppressed.

[Energy Line Curing Resin (G)]

Component (III) and the thermosetting protective film may also contain energy-curing resin (G). The thermosetting protective film, by containing energy-curing resin (G), can have its properties altered by irradiation with energy rays.

Line-curing resins (G) are line-curing compounds, or can be considered as oligomers or polymers (polymers) synthesized from line-curing compounds.

Examples of the aforementioned energy line hardening compounds include compounds having at least one polymerizable double bond within the molecule, preferably acrylate compounds having a (meth)acrylic group.

Examples of the aforementioned acrylate compounds include: trihydroxymethylpropane tri(meth)acrylate, tetrahydroxymethylmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and other (meth)acrylates containing a chain-like aliphatic backbone; dicyclopentyl(meth)acrylate and other (meth)acrylates containing a cyclic aliphatic backbone; polyethylene glycol di(meth)acrylate and other polyalkylene glycol (meth)acrylates; oligoester (meth)acrylates; (meth)acrylate aminocarbamate oligomers; epoxy-modified (meth)acrylates; polyether (meth)acrylates other than the aforementioned polyalkylene glycol (meth)acrylates; and isoconic acid oligomers.

The aforementioned energy line hardening compound preferably has a weight-average molecular weight of 100 to 30,000, more preferably 300 to 10,000.

The energy line hardening compound used in the synthesis of the aforementioned oligomers or polymers may be one type or two or more types. When two or more types are used, the combination and ratio of those energy line hardening compounds can be arbitrarily selected.

The energy-curing resin (G) contained in component (III) and the thermosetting protective film can be one type or two or more types. When there are two or more types, the combination and ratio of those energy-curing resins (G) can be arbitrarily selected.

When using a line-curing resin (G), the content of the line-curing resin (G) in composition (III) relative to the total mass of composition (III) is preferably from 1% to 30% by mass, more preferably from 5% to 25% by mass, and particularly preferably from 10% to 20% by mass.

[Photopolymerization Initiator (H)]

When component (III) and the thermosetting protective film form contain energy line curing resin (G), a photopolymerization initiator (H) may also be included to facilitate the efficient polymerization reaction of the energy line curing resin (G).

Examples of photopolymerization initiators (H) in composition (III) include: benzoin compounds such as benzoin methyl benzoate, benzoin ethyl benzoate, benzoin isopropyl benzoate, benzoin isobutyl benzoate, benzoic acid, methyl benzoate, and benzoin dimethyl ketone; acetophenone compounds such as 2-hydroxy-2-methyl-1-phenylpropane-1-one, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropenyl)benzyl)phenyl)-2-methylpropane-1-one, and 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone; and bis(2,4,6) Azoxyphosphine oxide compounds such as 2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; sulfide compounds such as benzylphenyl sulfide and tetramethylthiuram monosulfide; α-keto alcohol compounds such as 1-hydroxycyclohexylphenyl ketone; azo compounds such as azobisisobutyronitrile; titanium eccentricate compounds such as titanium eccentricate; thiotonone compounds such as thiotonone; peroxide compounds; diketone compounds such as diacetate; benzohexane; dibenzohexane; benzophenone; 2,4-diethylthiotonone; 1,2-diphenylmethane; 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone; quinone compounds such as 1-chloroanthraquinone and 2-chloroanthraquinone.

Furthermore, photosensitizers such as amines can also serve as photopolymerization initiators (H).

The photopolymerization initiator (H) contained in component (III) and the thermosetting protective film can be one type or two or more types. When there are two or more types, the combination and ratio of those photopolymerization initiators (H) can be arbitrarily selected.

When using a photopolymerization initiator (H), in composition (III), the content of the photopolymerization initiator (H) is preferably 0.1 to 20 parts by mass relative to 100 parts by mass of the energy line curing resin (G), more preferably 1 to 10 parts by mass, and particularly preferably 2 to 5 parts by mass.

[Colorant (I)]

Component (III) and the thermosetting protective film forming film preferably contain a colorant (I). By containing colorant (I), the light transmittance of the thermosetting protective film forming film and the protective film can be easily adjusted.

As coloring agents (I), examples include known coloring agents such as inorganic pigments, organic pigments, and organic dyes.

Examples of organic pigments and dyes mentioned above include: amine-based pigments, anthocyanin-based pigments, polyanthocyanin-based pigments, ketone-based pigments, squaric acid-based pigments, azuron-based pigments, polymethyl-based pigments, naphthoquinone-based pigments, pyranone-based pigments, phthalocyanine-based pigments, naphthyl phthalocyanine-based pigments, naphthyl lactone-based pigments, azo-based pigments, condensed azo-based pigments, indigo-based pigments, violet-based pigments, and perylene-based pigments. The pigments include: bisoxazine pigments, quinacridone pigments, isoindolineone pigments, quinolinephthalone pigments, pyrrole pigments, indigo pigments, metal complex pigments (metallic salt dyes), dithiol metal complex pigments, indophenol pigments, triarylmethane pigments, anthraquinone pigments, naphthol pigments, methylene azo pigments, benzimidazole pigments, pinantrone pigments, and vat pigments, etc.

Examples of inorganic pigments mentioned above include: carbon black, cobalt-based pigments, iron-based pigments, chromium-based pigments, titanium-based pigments, vanadium-based pigments, zirconium-based pigments, molybdenum-based pigments, ruthenium-based pigments, platinum-based pigments, ITO (indium tin oxide) pigments, and ATO (antimony tin oxide) pigments.

The colorant (I) contained in component (III) and the thermosetting protective film can be only one type or two or more types. When there are two or more types, the combination and ratio of those colorants (I) can be arbitrarily selected.

When using a colorant (I), the content of the colorant (I) in the thermosetting protective film can be adjusted appropriately according to the purpose. For example, by adjusting the content of the colorant (I) in the thermosetting protective film, the light transmittance of the thermosetting protective film can be adjusted, thereby adjusting the legibility of the printed text when laser printing is performed on the thermosetting protective film or the protective film. Furthermore, by adjusting the content of the colorant (I) in the thermosetting protective film, the design of the protective film can also be improved, or the grinding marks on the inner surface of the wafer can be made less visible. Taking these aspects into consideration, the content of colorant (I) in the thermosetting protective film, relative to the total mass of the thermosetting protective film, is preferably 0.1% to 10% by mass, more preferably 0.1% to 7.5% by mass, and particularly preferably 0.1% to 5% by mass. By keeping the aforementioned proportion above the lower limit, the effects of using colorant (I) can be more significantly obtained. For example, when the thermosetting protective film is peeled off from the adherend, it is easy to visually confirm whether any residue of the thermosetting protective film remains on the adherend. By keeping the aforementioned proportion below the upper limit, excessive use of colorant (I) can be suppressed.

[General Additives (J)]

Component (III) and the thermosetting protective film may also contain a general additive (J) to the extent that it does not impair the effects of the invention.

The general-purpose additive (J) can be any known additive, and can be selected arbitrarily according to the purpose without particular limitation. Examples of preferred general-purpose additives (J) include: plasticizers, antistatic agents, antioxidants, gettering agents, and ultraviolet absorbers.

The general-purpose additive (J) contained in component (III) and the thermosetting protective film can be only one type or two or more types. When there are two or more types, the combination and ratio of those general-purpose additives (J) can be arbitrarily selected.

There are no particular limitations on the content of component (III) and the general additive (J) for forming the thermosetting protective film; they can be selected appropriately according to the purpose.

[solvent]

Composition (III) is preferably further found to contain a solvent. The operability of composition (III) containing a solvent is improved.

In this instruction manual, the term "solvent," unless otherwise specified, refers not only to substances that dissolve the target components but also to dispersion media that disperse the target components.

The aforementioned solvents are not particularly limited, but preferred solvents include: hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, 2-propanol, isobutanol (2-methylpropane-1-ol), and 1-butanol; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; and amides (compounds containing amide bonds) such as dimethylformamide and N-methylpyrrolidone.

Component (III) may contain only one solvent or two or more solvents. When there are two or more solvents, the combination and ratio of those solvents can be arbitrarily selected.

Regarding the solvent contained in component (III), examples of better solvents that can more uniformly mix the components contained in component (III) include: methyl ethyl ketone, toluene, ethyl acetate, etc.

The solvent content of component (III) is not particularly limited; for example, it can be appropriately selected based on the types of components other than the solvent.

[Method for manufacturing a thermosetting protective film component (III)]

Composition (III) can be obtained by formulating the components used to constitute composition (III).

There are no particular restrictions on the order in which the ingredients are added when preparing the formula, and two or more ingredients may be added simultaneously.

There are no particular limitations on the method of mixing the ingredients during preparation; any of the following known methods may be appropriately selected: mixing by rotating a stir bar or stirring blade; mixing using a mixer; mixing by applying ultrasound, etc.

There are no particular restrictions on the temperature and time for adding and mixing the ingredients, as long as they do not degrade the composition. Appropriate adjustments are sufficient, with an optimal temperature range of 15°C to 30°C.

◎Energy Line Hardening Protective Film Formation

The curing conditions for forming a protective film by attaching a line-curing protective film to the target area of a wafer and curing it with energy lines are not particularly limited, as long as the protective film can fully perform its function. The curing degree can be appropriately selected according to the type of line-curing protective film.

For example, the illuminance of the energy line during energy line curing of the protective film is preferably between 120 mW/ ^cm² and 280 mW/ ^cm² . Furthermore, the light intensity of the energy line during the aforementioned curing is preferably between 100 mJ/ ^cm² and 1000 mJ/ ^cm² .

[Component for forming energy line hardening protective film (IV)]

As a preferred composition for forming a line-curing protective film, examples include composition (IV) for forming a line-curing protective film containing the aforementioned line-curing component (a) (in this specification, it is sometimes simply referred to as "composition (IV)").

[Energy Line Hardening Component (a)]

The energy-curing component (a) is a component that is cured by irradiation with energy rays. It is also used to impart film-forming properties or flexibility to the energy-curing protective film, and forms a hard protective film after curing.

In the energy-line hardening protective film, the energy-line hardening component (a) is preferably unhardened, more preferably adhesive, and even more preferably both unhardened and adhesive.

Examples of energy line hardening components (a) include, for instance, polymers (a1) having energy line hardening groups and a weight average molecular weight of 80,000 to 2,000,000, and compounds (a2) having energy line hardening groups and a molecular weight of 100 to 80,000. The aforementioned polymer (a1) may be at least partially crosslinked using a crosslinking agent, or it may not be crosslinked.

[Polymers possessing energy-line hardening groups and a weight-average molecular weight of 80,000 to 2,000,000 (a1)]

As a polymer (a1) having an energy-line hardening group and a weight-average molecular weight of 80,000 to 2,000,000, an example of a polymer (a1-1) is an acrylic resin (a1-1) having a structure in which an acrylic polymer (a11) and an energy-line hardening compound (a12) have reacted. The acrylic polymer (a11) has functional groups capable of reacting with groups found in other compounds, and the energy-line hardening compound (a12) has energy-line hardening groups such as groups that react with the aforementioned functional groups and energy-line hardening double bonds.

Examples of functional groups that can react with groups found in other compounds include hydroxyl, carboxyl, amino, substituted amino groups (groups with one or two hydrogen atoms of an amino group replaced by groups other than hydrogen atoms), and epoxy groups. However, for the purpose of preventing corrosion of circuits such as wafers or chips, the aforementioned functional groups are preferably groups other than carboxyl groups.

Of these functional groups, the hydroxyl group is preferred.

• Acrylic polymers with functional groups (a11)

Examples of the aforementioned functionalized acrylic polymers (a11) include: acrylic polymers copolymerized from the aforementioned functionalized acrylic monomers and the aforementioned non-functionalized acrylic monomers; and acrylic polymers copolymerized from monomers other than acrylic monomers (non-acrylic monomers).

Furthermore, the aforementioned acrylic polymer (a11) can be a random copolymer or a block copolymer, and the polymerization method can also employ known methods.

Examples of acrylic monomers possessing the aforementioned functional groups include: monomers containing hydroxyl groups, monomers containing carboxyl groups, monomers containing amino groups, monomers containing substituted amino groups, and monomers containing epoxy groups.

Examples of hydroxyl-containing monomers mentioned above include: hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and other hydroxyalkyl esters of (meth)acrylate; and non-(meth)acrylate unsaturated alcohols (unsaturated alcohols without a (meth)acrylate backbone) such as vinyl alcohol and allyl alcohol.

Examples of the aforementioned carboxyl-containing monomers include: vinyl unsaturated monocarboxylic acids (monocarboxylic acids with vinyl unsaturated bonds), such as (meth)acrylic acid and butenoic acid; vinyl unsaturated dicarboxylic acids (dicarboxylic acids with vinyl unsaturated bonds), such as fumaric acid, icosinic acid, maleic acid, and leuconic acid; anhydrides of the aforementioned vinyl unsaturated dicarboxylic acids; and carboxyl alkyl esters of (meth)acrylic acid, such as 2-carboxyethyl methacrylate.

The aforementioned acrylic monomers with functional groups are preferably monomers containing hydroxyl groups.

The aforementioned acrylic monomers with functional groups constituting the aforementioned acrylic polymer (a11) may be one type or two or more types. When there are two or more types, the combination and ratio of those acrylic monomers can be arbitrarily selected.

Examples of non-functional acrylic monomers mentioned above include: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, dibutyl methacrylate, tributyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, and isononyl methacrylate. Alkyl esters comprising decyl methacrylate, undecyl methacrylate, dodecyl methacrylate (laurate methacrylate), tridecyl methacrylate, tetradecyl methacrylate (myristyl methacrylate), pentadecyl methacrylate, hexadecyl methacrylate (palmitoyl methacrylate), heptadecanyl methacrylate, and octadecyl methacrylate (stearyl methacrylate) are alkyl esters of methacrylate in which the alkyl group has a chain structure with 1 to 18 carbon atoms.

Furthermore, examples of non-functional acrylic monomers mentioned above include: methoxymethyl methacrylate, methoxyethyl methacrylate, ethoxymethyl methacrylate, ethoxyethyl methacrylate, and other alkoxyalkyl-containing (meth)acrylates; aromatic (meth)acrylates such as aryl (meth)acrylates including phenyl (meth)acrylate; non-crosslinked (meth)acrylamide and its derivatives; and non-crosslinked tertiary amino (meth)acrylates such as N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate.

In this specification, if a particular compound has a structure in which one or more hydrogen atoms are replaced by groups other than hydrogen atoms, then such a compound with a substituted structure is referred to as a "derivative" of the aforementioned particular compound.

In this specification, the term "base" refers not only to a group of atoms bonded together to form a structure, but also to a single atom.

The aforementioned non-functional acrylic monomer constituting the acrylic polymer (a11) may be a single type or two or more types. When there are two or more types, the combination and ratio of those acrylic monomers can be arbitrarily selected.

Examples of non-acrylic acid monomers mentioned above include: alkenes such as ethylene and norbenzene; vinyl acetate; and styrene.

The aforementioned non-acrylic monomers constituting the acrylic polymer (a11) may be one type or two or more types. When there are two or more types, the combination and ratio of those non-acrylic monomers can be arbitrarily selected.

In the aforementioned acrylic polymer (a11), the proportion (content) of the constituent units derived from the aforementioned functional acrylic monomers relative to the total amount of constituent units constituting the acrylic polymer (a11) is preferably 0.1% to 50% by mass, more preferably 1% to 40% by mass, and particularly preferably 3% to 30% by mass. Within this range, the aforementioned acrylic resin (a1-1) obtained by copolymerizing the aforementioned acrylic polymer (a11) and the aforementioned energy-curing compound (a12) readily forms a protective film with an appropriate content of energy-curing groups, allowing the curing degree of the protective film to be adjusted to a preferred range.

The acrylic polymer (a11) constituting the aforementioned acrylic resin (a1-1) may be a single type or two or more types. When there are two or more types, the combination and ratio of those acrylic polymers (a11) can be arbitrarily selected.

In the energy line curing protective film forming film, the content of acrylic resin (a1-1) relative to the total mass of the energy line curing protective film forming film is preferably 1% to 70% by mass, more preferably 5% to 60% by mass, and particularly preferably 10% to 50% by mass.

• Energy line hardening compound (a12)

The aforementioned energy line curing compound (a12) preferably has one or more groups selected from the group consisting of isocyanate groups, epoxy groups, and carboxyl groups as functional groups capable of reacting with the aforementioned acrylic polymer (a11), more preferably having an isocyanate group as such a group. When the aforementioned energy line curing compound (a12) has, for example, an isocyanate group as such a group, that isocyanate group reacts with the hydroxyl group of the acrylic polymer (a11) having a hydroxyl group as such a functional group.

The number of the aforementioned energy-line hardening groups in one molecule of the aforementioned energy-line hardening compound (a12) is not particularly limited; for example, it can be appropriately selected considering physical properties such as the shrinkage rate required for the target protective film.

For example, the aforementioned energy line hardening compound (a12) preferably has one to five aforementioned energy line hardening groups per molecule, more preferably one to three.

Examples of the aforementioned energy line hardening compounds (a12) include: 2-methacryloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloxyisocyanate, allyl isocyanate, and 1,1-(bisacryloxymethyl)ethyl isocyanate; acrylonitrile monoisocyanate compounds obtained by reacting diisocyanate compounds or polyisocyanate compounds with hydroxyethyl (meth)acrylate; and acrylonitrile monoisocyanate compounds obtained by reacting diisocyanate compounds or polyisocyanate compounds, polyol compounds, and hydroxyethyl (meth)acrylate, etc.

Of these, the aforementioned energy line hardening compound (a12) is preferably 2-methylacryloxyethyl isocyanate.

The energy-curing compound (a12) constituting the aforementioned acrylic resin (a1-1) may be a single compound or two or more compounds. When there are two or more compounds, the combination and ratio of those energy-curing compounds (a12) can be arbitrarily selected.

In the aforementioned acrylic resin (a1-1), the content of the energy-curing group derived from the aforementioned energy-curing compound (a12) relative to the content of the aforementioned functional groups derived from the aforementioned acrylic polymer (a11) is preferably 20 mol% to 120 mol%, more preferably 35 mol% to 100 mol%, and particularly preferably 50 mol% to 100 mol%. With the aforementioned content within this range, the adhesion of the cured material formed by the energy-curing protective film becomes greater. Furthermore, when the aforementioned energy-curing compound (a12) is a single-functional compound (having one of the aforementioned groups in one molecule), the upper limit of the aforementioned content is 100 mol%, but when the aforementioned energy-curing compound (a12) is a multifunctional compound (having two or more of the aforementioned groups in one molecule), the upper limit of the aforementioned content sometimes exceeds 100 mol%.

The weight-average molecular weight (Mw) of the aforementioned polymer (a1) is preferably from 100,000 to 2,000,000, more preferably from 300,000 to 1,500,000.

The aforementioned polymer (a1) contained in the component (IV) and the energy line hardening protective film can be only one type or two or more types. When there are two or more types, the combination and ratio of those polymers (a1) can be arbitrarily selected.

[Compounds with energy-line hardening groups and molecular weights ranging from 100 to 80,000 (a2)]

Examples of energy-line hardening groups in compounds (a2) having an energy-line hardening group and a molecular weight of 100 to 80,000 include groups containing energy-line hardening double bonds; preferred examples include (meth)acrylic acid groups, vinyl groups, etc.

The aforementioned compound (a2) is not particularly limited as long as it meets the above conditions, and examples include: low molecular weight compounds with energy-line hardening groups, epoxy resins with energy-line hardening groups, and phenolic resins with energy-line hardening groups.

Among the aforementioned compound (a2), low molecular weight compounds having energy line hardening groups include, for example, multifunctional monomers or oligomers, and preferably acrylate compounds having (meth)acrylic groups.

Examples of the aforementioned acrylate compounds include, for instance, those described in paragraph [0195] of International Patent Publication No. 2017-188197.

Among the aforementioned compound (a2), epoxy resins having energy-curing groups and phenolic resins having energy-curing groups, such as those described in paragraph [0043] of Japanese Patent Application Publication No. 2013-194102, can be used. Although such resins are also equivalent to the resins constituting the thermosetting components described later, they are used as compound (a2) in composition (IV).

The weight-average molecular weight of the aforementioned compound (a2) is preferably from 100 to 30,000, more preferably from 300 to 10,000.

The aforementioned compound (a2) contained in component (IV) and the energy line hardening protective film can be only one type or two or more types. When there are two or more types, the combination and ratio of those compounds (a2) can be arbitrarily selected.

[Polymers without energy line hardening groups (b)]

When the composition (IV) and the energy line hardening protective film forming film contain the aforementioned compound (a2) as the aforementioned energy line hardening component (a), it is preferable that it also contains a polymer (b) that does not have an energy line hardening group.

Examples of polymers (b) that do not possess energy-line hardening groups include: acrylic polymers, phenoxy resins, urethane resins, polyesters, rubber-based resins, and urethane acrylate resins.

Of these, polymer (b) is preferably an acrylic polymer (hereinafter, sometimes simply referred to as "acrylic polymer (b-1)").

As for the acrylic polymer (b-1), an example of an acrylic polymer identical to the polymer component (A) described above can be cited. However, the acrylic polymer (b-1) does not possess energy line hardening groups.

When the aforementioned polymer (b) has functional groups such as glycidyl, hydroxyl, substituted amine, carboxyl, or amine, the aforementioned polymer (b) can also be crosslinked using a crosslinking agent.

The aforementioned functional groups can be appropriately selected according to the type of crosslinking agent, and there are no particular limitations. For example, when the crosslinking agent is a polyisocyanate compound, hydroxyl, carboxyl, and amino groups can be used as the aforementioned functional groups, among which hydroxyl groups, which have high reactivity with isocyanate groups, are preferred. Similarly, when the crosslinking agent is an epoxy compound, carboxyl and amino groups can be used as the aforementioned functional groups, among which carboxyl groups, which have high reactivity with epoxy groups, are preferred. However, for the purpose of preventing corrosion of the circuitry on the wafer or chip, the aforementioned functional groups are preferably groups other than carboxyl groups.

The polymer (b) without energy-line hardening groups contained in component (IV) and the energy-line hardening protective film can be only one type or two or more types. When there are two or more types, the combination and ratio of those polymers (b) without energy-line hardening groups can be arbitrarily selected.

Composition (IV) may include compositions containing any one or both of the aforementioned polymer (a1) and compound (a2). Furthermore, when composition (IV) contains compound (a2), it is preferable that it also contains a polymer (b) without a line-hardening group; in this case, it is also preferable that it contains the aforementioned polymer (a1). Alternatively, composition (IV) may not contain compound (a2) and may contain both the aforementioned polymer (a1) and polymer (b) without a line-hardening group.

When composition (IV) contains the aforementioned polymer (a1), the aforementioned compound (a2), and a polymer (b) without a line-hardening group, the content of the aforementioned compound (a2) in composition (IV) is preferably 10 to 400 parts by mass, more preferably 30 to 350 parts by mass, relative to 100 parts by mass of the total content of the aforementioned polymer (a1) and the polymer (b) without a line-hardening group.

In the energy-line curable protective film forming membrane, the total content of the aforementioned energy-line curable component (a) and the polymer (b) without energy-line curable groups, relative to the total mass of the energy-line curable protective film forming membrane, is preferably 5% to 90% by mass, more preferably 10% to 80% by mass, and particularly preferably 20% to 70% by mass. Within this range, the film-forming properties, flexibility, and energy-line curing properties of the energy-line curable protective film forming membrane are improved.

In addition to the energy-curing component (a), composition (IV) may, depending on its purpose, contain one or more of the following: selected from the group consisting of thermosetting components, fillers, coupling agents, crosslinking agents, photopolymerization initiators, colorants, and general additives.

The aforementioned thermosetting components, fillers, coupling agents, crosslinking agents, photopolymerization initiators, colorants, and general additives in composition (IV) may include components that are identical to those in composition (III) such as thermosetting component (B), filler (D), coupling agent (E), crosslinking agent (F), photopolymerization initiator (H), colorant (I), and general additive (J).

Energy-curing protective films containing these components can achieve the same effects as thermosetting protective films containing these components.

In particular, photopolymerization initiators enable the energy line hardening reaction to proceed efficiently; therefore, energy line hardening protective films preferably contain photopolymerization initiators.

In composition (IV), the aforementioned thermosetting component, filler, coupling agent, crosslinking agent, photopolymerization initiator, colorant, and general additive may each be used individually or in combination of two or more. When two or more are used, the combination and ratio of these components can be arbitrarily selected.

The content of the aforementioned thermosetting components, fillers, coupling agents, crosslinking agents, photopolymerization initiators, colorants, and general additives in composition (IV) may be adjusted appropriately according to the purpose, and there are no particular limitations.

In terms of improving operability through dilution, component (IV) preferably contains a solvent.

As for the solvent contained in component (IV), examples include solvents identical to those in component (III).

The solvent contained in component (IV) may be only one type or may be two or more types.

There are no particular limitations on the solvent content of component (IV); for example, it can be appropriately selected based on the types of components other than the solvent.

[Manufacturing Method of Component (IV) for Forming Energy Line Hardening Protective Film]

Composition (IV) can be obtained by formulating the components used to constitute composition (IV).

The composition for forming an energy line curable protective film can be manufactured using the same method as the previously described composition for forming a thermosetting protective film, except for the difference in the types of formulations.

◎Non-hardening protective film formation

As a preferred type of non-curing protective film forming film, an example is a non-curing protective film forming film containing thermoplastic resins and fillers.

[Component for forming non-hardening protective films (V)]

As a preferred composition for forming a non-curing protective film, examples include composition (V) containing the aforementioned thermoplastic resin and filler (sometimes referred to simply as "composition (V)" in this specification).

[Thermoplastic resin]

The aforementioned thermoplastic resins are not specifically limited.

As for the aforementioned thermoplastic resins, more specifically, examples include non-curing thermoplastic resins such as acrylic resins, polyesters, polyurethanes, phenoxy resins, polybutene, polybutadiene, and polystyrene, which are included as components of composition (III) above.

The thermoplastic resin contained in the composition (V) and the non-curing protective film can be one type or two or more types. When there are two or more types, the combination and ratio of those thermoplastic resins can be arbitrarily selected.

In the non-curing protective film forming film, the content of the aforementioned thermoplastic resin relative to the total mass of the non-curing protective film forming film is preferably 25% to 75% by mass.

[Filling Material]

The non-curing protective film containing filler forms a film that exhibits the same effect as the thermosetting protective film containing filler (D).

As fillers contained in composition (V) and the non-curing protective film forming film, examples can be made of fillers identical to those contained in composition (III) and the thermosetting protective film forming film (D).

The filler contained in the composition (V) and the non-curing protective film can be one type or two or more types. When there are two or more types, the combination and ratio of those fillers can be arbitrarily selected.

In the non-curing protective film forming film, the filler content relative to the total mass of the non-curing protective film forming film is preferably 25% to 75% by mass. Within this range, as with the use of component (III), it becomes easier to adjust the coefficient of thermal expansion of the non-curing protective film forming film and the protective film.

In addition to the aforementioned thermoplastic resins and fillers, composition (V) may also contain other components depending on its purpose.

The other ingredients mentioned above are not particularly limited and can be chosen arbitrarily according to the purpose.

For example, by using a composition (V) containing the aforementioned thermoplastic resin and colorant, the formed non-curing protective film and protective film exhibit the same effect as the previously described thermosetting protective film containing colorant (I).

In composition (V), the aforementioned other components may be used individually or in combination of two or more. When two or more are used, the combination and ratio of those other components can be arbitrarily selected.

The content of the other components mentioned above in composition (V) can be adjusted appropriately according to the intended purpose, and there are no particular limitations.

In terms of improving operability through dilution, component (V) preferably contains a solvent.

As for the solvent contained in composition (V), examples include solvents identical to those in composition (III) described above.

The solvent contained in component (V) may be only one type or may be two or more types.

There is no particular limitation on the solvent content of component (V); for example, it can be appropriately selected according to the types of components other than the solvent.

[Method for manufacturing a non-hardening protective film forming component (V)]

Composition (V) can be obtained by blending the components used to constitute composition (V).

Non-curable protective film forming components, for example, can be manufactured using the same method as the previously described thermosetting protective film forming components, except for the difference in the types of formulations.

◎Examples of protective film formation

Figure 1 is a schematic cross-sectional view illustrating one example of a protective film forming membrane according to this embodiment. Furthermore, for ease of understanding of the features of this invention, the figures used in the following description may show enlarged portions of the main components; the dimensional ratios of the constituent elements may not be identical to the actual dimensions.

The protective film forming film 13 shown here has a first peeling film 151 on one side (sometimes referred to as the "first side" in this specification) 13a, and a second peeling film 152 on the opposite side (sometimes referred to as the "second side" in this specification) 13b.

Such a protective film, forming film 13, is suitable for preservation, for example, in a roller shape.

When the aforementioned tensile test was performed using the protective film to form the film 13, the aforementioned strain (0.1 N/ ^mm² ) was 0.5% or more, and the aforementioned strain (0.6 N/ ^mm² ) was 200% or less.

The protective film forming film 13 can be formed using the above-described protective film forming composition.

Both the first exfoliating membrane 151 and the second exfoliating membrane 152 can be known exfoliating membranes.

The first peeling membrane 151 and the second peeling membrane 152 may be identical or different from each other (for example, the peeling forces required for the self-protective membrane forming membrane 13 to peel off may be different, etc.).

Regarding the protective film 13 shown in Figure 1, the exposed surface resulting from the removal of either the first release film 151 or the second release film 152 becomes the attachment surface facing the inner surface of the wafer (not shown). Then, in the case of using the support sheet or dicing sheet described later, the exposed surface of the protective film 13 resulting from the removal of the remaining one of the first release film 151 and the second release film 152 becomes the attachment surface of the aforementioned support sheet or dicing sheet.

Figure 1 shows an example where the peeling membrane is disposed on both sides (first side 13a, second side 13b) of the protective film forming membrane 13. However, the peeling membrane may also be disposed on only one side of the protective film forming membrane 13, that is, only on the first side 13a or only on the second side 13b.

As an example of a preferred protective film forming film of this embodiment, a protective film forming film was subjected to a tensile test (a test piece of the aforementioned protective film forming film laminate, which is a plurality of sheets, was held with two sections spaced 30 mm apart, and the test piece was stretched at a speed of 1000 mm/min in a direction parallel to the surface of the test piece between the two sections, and the stress generated in the test piece and the strain of the test piece in the tensile direction were measured). When the stress initially reached 0.1 N/ ^mm² , the strain was 0.5% or more, and when the stress initially reached 0.6 N/mm², the strain was... The aforementioned strain at time ² is less than 200%; the aforementioned protective film forming film is thermosetting; the aforementioned protective film forming film contains: polymer component (A), epoxy resin (B1), thermosetting agent (B2), and filler (D); the aforementioned polymer component (A) is acrylic resin, the aforementioned acrylic resin having a constituent unit derived from (meth)acrylate alkyl ester, and the alkyl group constituting the alkyl ester in the aforementioned (meth)acrylate alkyl ester has 6 or more carbon atoms, and the aforementioned alkyl group is a chain structure acrylic resin, or an acrylic resin having a constituent unit derived from acrylonitrile; In the protective film forming membrane, the content of the aforementioned polymer component (A) relative to the total mass of the aforementioned protective film forming membrane is any one of 10% to 85% by mass, 15% to 70% by mass, 15% to 55% by mass, 15% to 40% by mass, 25% to 70% by mass, and 30% to 60% by mass; in the aforementioned protective film forming membrane, relative to 100 parts by mass of the aforementioned epoxy resin (B1), the content of the aforementioned thermosetting agent (B2) is 0.1 parts by mass to 100 parts by mass, 0.5 parts by mass to 50 parts by mass, 0.5 parts by mass, and 0.5 parts by mass. The amount of the protective film formed is from 25 parts by weight, 0.5 parts by weight to 10 parts by weight, and 0.5 parts by weight to 5 parts by weight; in the aforementioned protective film forming film, relative to the total content of the aforementioned polymer component (A), epoxy resin (B1) and thermosetting agent (B2) of 100 parts by weight, the total content of the aforementioned epoxy resin (B1) and thermosetting agent (B2) is from 10 parts by weight to 70 parts by weight, 20 parts by weight to 60 parts by weight, 25 parts by weight to 50 parts by weight, and 30 parts by weight to 45 parts by weight; in the aforementioned protective film forming film, the content of the aforementioned filler (D) is relative to the aforementioned The proportion of the total mass of the protective film forming film is any one of 15% to 70%, 25% to 70%, 35% to 70%, 45% to 70%, 50% to 70%, 55% to 70%, 15% to 60%, and 15% to 55%; wherein, in the aforementioned protective film forming film, the total content of the aforementioned polymer component (A), epoxy resin (B1), thermosetting agent (B2) and filler (D) relative to the total mass of the aforementioned protective film forming film does not exceed 100% by mass.

The surface roughness (Ra) of any one or both sides of this protective film can be any of the following: less than 300 nm, less than 100 nm, less than 50 nm, less than 40 nm, and less than 38 nm.

As another example of a preferred protective film forming film of this embodiment, a protective film forming film was subjected to a tensile test (a test piece of the aforementioned protective film forming film stack, which consists of multiple sheets, was held with two sections spaced 30 mm apart, and the test piece was stretched at a speed of 1000 mm/min in a direction parallel to the surface of the test piece between the two sections, and the stress generated in the test piece and the strain of the test piece in the tensile direction were measured). When the stress initially reached 0.1 N/ ^mm² , the strain was 0.5% or more, and when the stress initially reached 0.6 N/mm², the strain was... The aforementioned strain at time ² is less than 200%; the aforementioned protective film forming film is thermosetting; the aforementioned protective film forming film contains: polymer component (A), epoxy resin (B1), thermosetting agent (B2), and filler (D); the aforementioned polymer component (A) is acrylic resin, the aforementioned acrylic resin has a constituent unit derived from alkyl (meth)acrylate, and the alkyl group constituting the alkyl ester in the aforementioned (meth)acrylate has 6 or more carbon atoms, and the aforementioned alkyl group has a chain structure, and the amount of the constituent unit derived from the aforementioned (meth)acrylate relative to the total amount of the constituent units constituting the aforementioned acrylic resin is 50% to 75% by mass. Alternatively, the aforementioned acrylic resin has constituent units derived from acrylonitrile, and the amount of the aforementioned constituent units derived from acrylonitrile relative to the total amount of constituent units constituting the aforementioned acrylic resin is 15% to 45% by mass; in the aforementioned protective film forming film, the content of the aforementioned polymer component (A) relative to the total mass of the aforementioned protective film forming film is any one of 10% to 85% by mass, 15% to 70% by mass, 15% to 55% by mass, 15% to 40% by mass, 25% to 70% by mass, and 30% to 60% by mass; in the aforementioned protective film forming film, relative to the aforementioned epoxy resin (B1)... The content of the aforementioned thermosetting agent (B2) is 100 parts by weight, and the content of the aforementioned thermosetting agent (B2) is any one of 0.1 parts by weight to 100 parts by weight, 0.5 parts by weight to 50 parts by weight, 0.5 parts by weight to 25 parts by weight, 0.5 parts by weight to 10 parts by weight, and 0.5 parts by weight to 5 parts by weight; in the aforementioned protective film forming film, relative to the total content of the aforementioned polymer component (A), epoxy resin (B1) and thermosetting agent (B2) being 100 parts by weight, the total content of the aforementioned epoxy resin (B1) and thermosetting agent (B2) is any one of 10 parts by weight to 70 parts by weight, 20 parts by weight to 60 parts by weight, 25 parts by weight to 50 parts by weight, and 30 parts by weight to 45 parts by weight. The protective film forming film is wherein the content of the filler (D) relative to the total mass of the protective film forming film is any one of 15% to 70% by mass, 25% to 70% by mass, 35% to 70% by mass, 45% to 70% by mass, 50% to 70% by mass, 55% to 70% by mass, 15% to 60% by mass, and 15% to 55% by mass; wherein the total content of the polymer component (A), epoxy resin (B1), thermosetting agent (B2) and filler (D) relative to the total mass of the protective film forming film is not more than 100% by mass.

When the aforementioned acrylic resin has the aforementioned constituent units derived from acrylonitrile, the aforementioned acrylic resin may further have constituent units derived from (meth)acrylate. In this case, the proportion of the aforementioned constituent units derived from acrylonitrile to the total amount of constituent units constituting the aforementioned acrylic resin may be 15% to 45% by mass, and the proportion of the aforementioned constituent units derived from (meth)acrylate to the total amount of constituent units constituting the aforementioned acrylic resin may be 65% to 85% by mass.

The surface roughness (Ra) of any one or both sides of this protective film can be any of the following: less than 300 nm, less than 100 nm, less than 50 nm, less than 40 nm, and less than 38 nm.

The protective film forming film of this embodiment, when used in conjunction with the support sheet described later, can constitute a composite sheet for forming a protective film capable of simultaneously forming and cutting the protective film. The following description pertains to such a composite sheet for forming a protective film.

◇Composite sheet for protective film formation

One embodiment of the present invention, a composite sheet for forming a protective film, comprises: a support sheet, and a protective film forming film disposed on one side of the support sheet; the protective film forming film is the protective film forming film of the aforementioned embodiment of the present invention.

The protective film forming composite sheet of this embodiment can be attached to the inner surface of a wafer via its protective film forming film. Then, the protective film forming film in the protective film forming composite sheet can be peeled off from the inner surface of the wafer while maintaining its position as a component of the protective film forming composite sheet, i.e., integrally with the support sheet, to achieve the purpose of reattaching another prepared protective film forming composite sheet or protective film. At this time, as previously described, the protective film forming film in the aforementioned protective film forming composite sheet can be peeled off normally and easily even when the inner surface of the wafer is rough, demonstrating excellent wafer remanufacturing adaptability.

In this specification, even after the protective film has hardened, as long as the laminated structure formed by the support sheet and the hardened protective film is maintained, this laminated structure is referred to as a "composite sheet for protective film formation".

The following is a detailed description of each layer of the composite sheet constituting the aforementioned protective film formation.

◎Supporting tablets

The aforementioned support sheet can be composed of a single layer or multiple layers (two or more). When the support sheet is composed of multiple layers, the materials and thicknesses of these multiple layers can be the same or different, and the combination of these multiple layers is not particularly limited as long as it does not impair the effect of the invention.

Support sheets can be either transparent or opaque, and can also be colored depending on the intended use.

When the protective film forms a film with energy line hardening properties, the support sheet is preferable to allow the energy line to pass through.

Examples of support sheets include: a support sheet comprising a substrate and an adhesive layer disposed on one side of the substrate; and a support sheet consisting solely of a substrate. When the support sheet has an adhesive layer, in a composite sheet for forming a protective film, the adhesive layer is disposed between the substrate and the protective film forming film.

When using a support sheet having a substrate and an adhesive layer, the adhesion and peelability between the support sheet and the protective film forming film can be easily adjusted in the protective film forming composite sheet.

When using a support sheet consisting solely of a substrate, it is possible to manufacture a composite sheet for forming a protective film at a low cost.

The following describes examples of composite sheets for forming protective films in this embodiment, with reference to the drawings, according to the types of such support sheets.

◎An example of a composite sheet for forming a protective film

Figure 2 is a schematic cross-sectional view illustrating an example of a composite sheet for forming a protective film according to this embodiment.

Furthermore, in the figures following Figure 2, for the same constituent elements shown in the previously explained figures, the same symbols are used as in the previously explained figures, and detailed descriptions of those constituent elements are omitted.

The protective film forming composite sheet 101 shown here comprises a support sheet 10 and a protective film forming film 13 disposed on one side of the support sheet 10 (sometimes referred to as the "first side" in this specification) 10a.

The support sheet 10 is composed of a substrate 11 and an adhesive layer 12 disposed on one side (first surface) 11a of the substrate 11. In the protective film forming composite sheet 101, the adhesive layer 12 is disposed between the substrate 11 and the protective film forming film 13.

That is, the protective film forming composite sheet 101 is formed by sequentially laminating a substrate 11, an adhesive layer 12, and a protective film forming film 13 in the thickness direction of these layers.

The first surface 10a of the support sheet 10 is the same as the side of the adhesive layer 12 opposite to the substrate 11 (sometimes referred to as "first surface" in this specification) 12a.

The protective film forming composite sheet 101 further comprises a jig adhesive layer 16 and a peeling membrane 15 on the protective film forming film 13.

In the protective film forming composite sheet 101, a protective film forming film 13 is laminated on the entire or substantially entire surface of the first surface 12a of the adhesive layer 12, and a jig adhesive layer 16 is laminated on a portion of the protective film forming film 13a on the side opposite to the adhesive layer 12 (sometimes referred to as the "first surface" in this specification), that is, in the area near the periphery. Furthermore, in the first surface 13a of the protective film forming film 13, a peeling film 15 is deposited in the area where the fixture adhesive layer 16 is not deposited, and on the side of the fixture adhesive layer 16 opposite to the protective film forming film 13 (sometimes referred to as the "first surface" in this specification) 16a. A support sheet 10 is provided on the side of the protective film forming film 13 opposite to the first surface 13a (sometimes referred to as the "second surface" in this specification) 13b.

Not limited to the protective film forming composite sheet 101, in the protective film forming composite sheet of this embodiment, the peeling membrane (e.g., the peeling membrane 15 shown in FIG. 2) has any configuration. The protective film forming composite sheet of this embodiment may or may not have a peeling membrane.

The adhesive layer 16 for the fixture is used to fix the protective film forming composite sheet 101 to a ring frame, etc.

The adhesive layer 16 for the fixture may, for example, have a single-layer structure containing adhesive or bonding agent components, or it may have a multi-layer structure (having a sheet as a core material, and layers containing adhesive or bonding agent components disposed on both sides of the aforementioned sheet).

The protective film forming composite sheet 101 is used as follows: with the peeling film 15 removed, the inner surface of the wafer is attached to the first surface 13a of the protective film forming film 13, and then the first surface 16a of the adhesive layer 16 is attached to a fixture such as a ring frame.

As described above, the protective film 13 maintains excellent wafer regeneration suitability even when the inner surface of the wafer is rough.

Figure 3 is a schematic cross-sectional view illustrating another example of the composite sheet for forming the protective film according to this embodiment.

The protective film forming composite sheet 102 shown here is identical to the protective film forming composite sheet 101 shown in Figure 2, except that the shape and size of the protective film forming film are different, and the adhesive layer for the fixture is deposited on the first surface of the adhesive layer rather than the first surface of the protective film forming film.

More specifically, in the protective film forming composite sheet 102, the protective film forming film 23 is deposited on a portion of the first surface 12a of the adhesive layer 12, that is, on the central side of the adhesive layer 12 in the width direction (left-right direction in FIG. 3). Furthermore, in the first surface 12a of the adhesive layer 12, in the area where the protective film forming film 23 is not deposited, a jig adhesive layer 16 is deposited around the protective film forming film 23 from the outer side in the width direction of the protective film forming film 23 in a non-contact manner. Furthermore, a release film 15 is deposited on the side of the protective film forming film 23 opposite to the adhesive layer 12 (sometimes referred to as the "first side" in this specification) 23a and the first side 16a of the fixture adhesive layer 16. A support sheet 10 is provided on the side of the protective film forming film 23 opposite to the first side 23a (sometimes referred to as the "second side" in this specification) 23b.

Figure 4 is a cross-sectional view schematically illustrating yet another example of the composite sheet for forming the protective film according to this embodiment.

The protective film forming composite sheet 103 shown here is identical to the protective film forming composite sheet 102 shown in FIG. 3, except that it lacks the adhesive layer 16 for the jig.

Figure 5 is a cross-sectional view schematically illustrating yet another example of the composite sheet for forming the protective film according to this embodiment.

The protective film forming composite sheet 104 shown here is identical to the protective film forming composite sheet 101 shown in FIG. 2, except that it is constructed with a support sheet 20 instead of a support sheet 10.

The support sheet 20 is composed solely of the substrate 11.

That is, the protective film forming composite sheet 104 is formed by depositing the substrate 11 and the protective film forming film 13 in the thickness direction of these layers.

One side of the support sheet 20 (the side of the protective film forming film 13; the first side) 20a is identical to the first side 11a of the substrate 11.

The protective film forming composite sheet of this embodiment is not limited to the protective film forming composite sheets shown in Figures 1 to 5. A portion of the protective film forming composite sheet shown in Figures 1 to 5 may be modified or deleted, or other components may be added to the protective film forming composite sheet described above, without impairing the effects of the invention.

Secondly, each layer that makes up the support sheet will be explained in detail.

○Substrate

The aforementioned substrate is in sheet or film form, and various resins can be cited as constituent materials of the aforementioned substrate.

Examples of the aforementioned resins include: polyethylene such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE); polyolefins other than polyethylene such as polypropylene, polybutene, polybutadiene, polymethylpentene, and noberonine resins; ethylene-based copolymers such as ethylene-vinyl acetate copolymer, ethylene-(meth)acrylate copolymer, ethylene-(meth)acrylate copolymer, and ethylene-noberonine copolymer (polymers obtained using ethylene as a monomer); vinyl chloride-based resins such as polyvinyl chloride and vinyl chloride copolymer (resins obtained using vinyl chloride as a monomer); polystyrene... Ethylene; polycyclic aromatic hydrocarbons; polyesters such as polyethylene terephthalate, polyethylene naphthalate, polyethylene terephthalate, polyethylene isophthalate, polyethylene 2,6-naphthalate, and fully aromatic polyesters whose constituent units are all aromatic cyclic groups; copolymers of two or more of the aforementioned polyesters; poly(meth)acrylates; polyurethane; polyurethane acrylates; polyimide; polyamide; polycarbonate; fluororesins; polyacetal; modified polyphenylene ether; polyphenylene sulfide; polyetherketone; etc.

Furthermore, as the aforementioned resin, examples include polymer alloys such as the aforementioned polyester and mixtures of resins other than polyester. Preferably, in polymer alloys of the aforementioned polyester and resins other than polyester, the amount of resins other than polyester is relatively small.

Furthermore, examples of the aforementioned resins include: crosslinked resins formed by crosslinking one or more of the aforementioned resins; and modified resins using one or more of the aforementioned ionic polymers, etc.

Regarding the aforementioned resin's excellent heat resistance, polypropylene or polybutylene terephthalate is preferred.

The resin constituting the substrate can be a single type or two or more types. When there are two or more types, the combination and ratio of those resins can be arbitrarily selected.

The substrate can consist of a single layer or multiple layers (two or more). When composed of multiple layers, these layers can be identical or different, and there are no particular limitations on their combination.

The substrate thickness is preferably 50 μm to 300 μm, more preferably 60 μm to 100 μm. With a substrate thickness within this range, the flexibility of the composite sheet used for forming the protective film and its adaptability to wafer bonding are further improved.

Here, "substrate thickness" refers to the overall thickness of the substrate. For example, the thickness of a substrate composed of multiple layers refers to the total thickness of all the layers that make up the substrate.

In addition to the aforementioned resins and other main constituent materials, the base material may also contain various known additives such as fillers, colorants, antioxidants, organic lubricants, catalysts, and plasticizers.

The substrate can be either transparent or opaque, and can be colored according to the purpose, or other layers can be vapor-deposited.

When the protective film forms a film with energy line hardening properties, the substrate is preferably designed to allow energy lines to pass through.

To adjust the adhesion between the substrate and layers disposed on it (e.g., adhesive layers, protective film forming films, or other aforementioned layers), the surface of the substrate can be subjected to surface treatments such as sandblasting, solvent treatment, etc.; oxidation treatments such as corona discharge treatment, electron beam irradiation treatment, plasma treatment, ozone/ultraviolet irradiation treatment, flame treatment, chromic acid treatment, hot air treatment, etc.; oleophilic treatment; hydrophilic treatment, etc. Additionally, a primer treatment can be applied to the substrate surface.

The substrate, by containing a specific range of components (e.g., resins), can also have adhesiveness on at least one side.

The substrate can be manufactured using known methods. For example, a resin-containing substrate can be manufactured by molding a resin composition containing the aforementioned resin.

○ Adhesive layer

The aforementioned adhesive layer is in sheet or film form and contains adhesive.

Examples of adhesives mentioned above include: acrylic resins, carbamate resins, rubber-based resins, polysiloxane resins, epoxy resins, polyvinyl ether, polycarbonate, ester-based resins, and other adhesive resins.

The adhesive layer can consist of a single layer or multiple layers (two or more). When it consists of multiple layers, these layers can be identical or different from each other, and there are no particular limitations on the combination of these layers.

The thickness of the adhesive layer is not particularly limited, but is preferably 1 μm to 100 μm, more preferably 1 μm to 60 μm, and even more preferably 1 μm to 30 μm.

Here, "adhesive layer thickness" refers to the overall thickness of the adhesive layer. For example, the thickness of an adhesive layer consisting of multiple layers refers to the total thickness of all the layers that make up the adhesive layer.

The adhesive layer can be either transparent or opaque, and can also be colored depending on the purpose.

When the protective film forms a film with energy line hardening properties, the adhesive layer is preferable to allow the energy line to penetrate.

The adhesive layer can be either line-cured or non-line-cured. Line-cured adhesive layers allow for adjustment of physical properties before and after curing. For example, curing the line-cured adhesive layer before picking up a protective-coated wafer (described later) makes it easier to pick up the protective-coated wafer.

In this specification, even after the energy line curing adhesive layer has been cured by energy lines, as long as the laminated structure formed by the substrate and the cured energy line curing adhesive layer is maintained, this laminated structure is referred to as a "support sheet".

An adhesive layer can be formed using an adhesive composition containing an adhesive. For example, an adhesive layer can be formed on the target area by applying the adhesive composition to the object to which the adhesive layer is to be formed and drying it as needed. The ratio of the components in the adhesive composition that do not vaporize at room temperature is usually the same as the ratio of the aforementioned components in the adhesive layer.

In the adhesive layer, the total content of one or more of the ingredients described below in the adhesive layer does not exceed 100% by mass relative to the total mass of the adhesive layer.

Similarly, in the adhesive composition, the aggregate content of one or more of the ingredients described below in the adhesive composition does not exceed 100% by mass relative to the total mass of the adhesive composition.

The application and drying of the adhesive composition can be performed, for example, using the same method as that used for the application and drying of the protective film forming composition described above.

When the adhesive layer is line-cured, examples of line-cured adhesive compositions include: an adhesive composition (I-1) containing a non-line-cured adhesive resin (I-1a) (hereinafter sometimes simply referred to as "adhesive resin (I-1a)") and a line-cured compound; an adhesive composition (I-2) containing a line-cured adhesive resin (I-2a) (hereinafter sometimes simply referred to as "adhesive resin (I-2a)") with unsaturated groups introduced into the side chains of the non-line-cured adhesive resin (I-1a); and an adhesive composition (I-3) containing the aforementioned adhesive resin (I-2a) and a line-cured compound.

When the adhesive layer is non-energy-line curing, examples of non-energy-line curing adhesive compositions include adhesive compositions (I-4) containing the aforementioned non-energy-line curing adhesive resin (I-1a).

[Non-energy-line-curing adhesive resin (I-1a)]

The aforementioned adhesive resin (I-1a) is preferably an acrylic resin.

Examples of the aforementioned acrylic resins include acrylic polymers having at least one constituent unit derived from (meth)acrylate alkyl esters.

As an example of the aforementioned alkyl (meth)acrylate, alkyl (meth)acrylates in which the alkyl group forming the alkyl ester has 1 to 20 carbon atoms are cited, wherein the alkyl group is preferably linear or branched.

The aforementioned acrylic polymer preferably has, in addition to structural units derived from alkyl (meth)acrylates, structural units derived from functionalized monomers.

As an example of the aforementioned functionalized monomers, one could cite monomers that become the starting point for crosslinking through a reaction between the aforementioned functionalized group and the crosslinking agent described later.

Examples of functionalized monomers include, for instance, monomers containing hydroxyl groups, carboxyl groups, amino groups, and epoxy groups.

In addition to constituent units derived from alkyl (meth)acrylates and functionalized monomers, the aforementioned acrylic polymers may also have constituent units derived from other monomers.

There are no particular limitations on the other monomers mentioned above, as long as they can copolymerize with alkyl (meth)acrylates, etc.

Other examples of the aforementioned monomers include: styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, acrylamide, etc.

In the aforementioned adhesive compositions (I-1), (I-2), (I-3), and (I-4) (hereinafter, including these adhesive compositions, they are collectively referred to as "Adhesive Compositions (I-1) to Adhesive Compositions (I-4)"), the aforementioned acrylic polymers and other acrylic resins may possess only one type of constituent unit, or two or more types. When there are two or more types, the combination and ratio of those constituent units can be arbitrarily selected.

In the aforementioned acrylic polymer, the proportion of the constituent units derived from functionalized monomers relative to the total amount of constituent units is preferably 1% to 35% by mass.

The adhesive composition (I-1) or adhesive composition (I-4) may contain only one type of adhesive resin (I-1a) or two or more types. When there are two or more types, the combination and ratio of those adhesive resins (I-1a) can be arbitrarily selected.

In the adhesive layer formed by adhesive composition (I-1) or adhesive composition (I-4), the content of adhesive resin (I-1a) relative to the total mass of the aforementioned adhesive layer is preferably from 5% to 99% by mass.

[Energy-curing adhesive resin (I-2a)]

The aforementioned adhesive resin (I-2a) can be obtained, for example, by reacting a compound containing unsaturated groups with energy-line polymerizable unsaturated groups with the functional groups in the adhesive resin (I-1a).

The aforementioned compounds containing unsaturated groups, in addition to the aforementioned energy-line polymerizable unsaturated groups, further possess groups that can bond with adhesive resin (I-1a) by reacting with functional groups in the adhesive resin (I-1a).

Examples of unsaturated groups with polymerizable energy lines include (meth)acryl, vinyl(ethylene), and allyl(2-propenyl), with (meth)acryl being preferred.

Examples of groups that can bond with functional groups in adhesive resins (I-1a) include isocyanate groups and glycidyl groups that can bond with hydroxyl or amino groups, and hydroxyl and amino groups that can bond with carboxyl or epoxy groups.

Examples of compounds containing unsaturated groups include, for instance, methacryloxyethyl isocyanate, methacrylyl isocyanate, and glycidyl methacrylate.

The adhesive composition (I-2) or adhesive composition (I-3) may contain only one type of adhesive resin (I-2a) or two or more types. When there are two or more types, the combination and ratio of those adhesive resins (I-2a) can be arbitrarily selected.

In the adhesive layer formed by adhesive composition (I-2) or adhesive composition (I-3), the content of adhesive resin (I-2a) relative to the total mass of the aforementioned adhesive layer is preferably 5% to 99% by mass.

[Energy line hardening compound]

As a component of the aforementioned adhesive composition (I-1) or adhesive composition (I-3), the aforementioned energy-line curing compound can be a monomer or oligomer having an energy-line polymerizable unsaturated group and capable of curing by irradiation with an energy line.

Examples of monomers in energy line hardening compounds include: trimethylolpropane tri(meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol (meth)acrylate, and other poly(meth)acrylates; methacrylate aminocarbamates; polyester (meth)acrylates; polyether (meth)acrylates; epoxy (meth)acrylates, etc.

Among energy-line hardening compounds, oligomers can be exemplified as polymers of the monomers already described above.

The adhesive composition (I-1) or adhesive composition (I-3) may contain only one or more of the aforementioned energy line curing compounds. When there are two or more, the combination and ratio of those energy line curing compounds can be arbitrarily selected.

In the adhesive layer formed by adhesive composition (I-1) or adhesive composition (I-3), the content of the aforementioned energy line hardening compound relative to the total mass of the aforementioned adhesive layer is preferably from 1% to 95% by mass.

[Cross-connecting agent]

As an adhesive resin (I-1a), when using the aforementioned acrylic polymer that, in addition to having constituent units derived from alkyl (meth)acrylates, also has constituent units derived from functionalized monomers, the adhesive composition (I-1) or adhesive composition (I-4) preferably further contains a crosslinking agent.

Furthermore, for example, when the aforementioned acrylic polymer, having the same constituent units derived from functionalized monomers as the acrylic polymer in the adhesive resin (I-1a), is used as the adhesive resin (I-2a), the adhesive composition (I-2) or adhesive composition (I-3) may further contain a crosslinking agent.

The aforementioned crosslinking agent, for example, reacts with the aforementioned functional groups to crosslink adhesive resins (I-1a) or adhesive resins (I-2a) with each other.

Examples of crosslinking agents include: isocyanate-based crosslinking agents such as toluene diisocyanate, hexamethylene diisocyanate, phenyl diisocyanate, and adducts of these diisocyanates (crosslinking agents with isocyanate groups); epoxy-based crosslinking agents such as ethylene glycol glycidyl ether (crosslinking agents with glycidyl groups); aziridine-based crosslinking agents such as hexa[1-(2-methyl)aziridinyl]triphosphatidyltriazine (crosslinking agents with aziridine groups); metal chelate-based crosslinking agents such as aluminum chelates (crosslinking agents with metal chelate structures); and isocyanurate-based crosslinking agents (crosslinking agents with an isocyanuric acid skeleton), etc.

The adhesive components (I-1) to (I-4) may contain only one type of crosslinking agent or two or more types. When there are two or more types, the combination and ratio of these crosslinking agents can be arbitrarily selected.

In the aforementioned adhesive composition (I-1) or adhesive composition (I-4), the content of the crosslinking agent is preferably 0.01 to 50 parts by weight, relative to 100 parts by weight of the adhesive resin (I-1a).

In the aforementioned adhesive composition (I-2) or adhesive composition (I-3), the content of the crosslinking agent is preferably 0.01 to 50 parts by weight, relative to 100 parts by weight of the adhesive resin (I-2a).

[Photopolymerization initiator]

Adhesive compositions (I-1), (I-2), and (I-3) (hereinafter, including these adhesive compositions, are collectively referred to as "adhesive compositions (I-1) to adhesive compositions (I-3)") may further contain a photopolymerization initiator. Adhesive compositions (I-1) to (I-3) containing a photopolymerization initiator undergo sufficient curing reaction even when irradiated with relatively low-energy rays such as ultraviolet light.

As a photopolymerization initiator, for example, a photopolymerization initiator identical to the aforementioned photopolymerization initiator (H) can be cited.

The adhesive compositions (I-1) to (I-3) may contain only one type of photopolymerization initiator or two or more types. When there are two or more types, the combination and ratio of those photopolymerization initiators can be arbitrarily selected.

In the adhesive composition (I-1), the content of the photopolymerization initiator is preferably 0.01 to 20 parts by mass relative to 100 parts by mass of the aforementioned energy line hardening compound.

In the adhesive composition (I-2), the content of the photopolymerization initiator is preferably 0.01 to 20 parts by weight relative to 100 parts by weight of the adhesive resin (I-2a).

In the adhesive composition (I-3), the content of the photopolymerization initiator is preferably 0.01 to 20 parts by mass relative to 100 parts by mass of the total content of the adhesive resin (I-2a) and the aforementioned energy line curing compound.

[Other Additives]

Adhesive compositions (I-1) to (I-4) may also contain other additives, not equivalent to any of the above-mentioned components, to the extent that they do not impair the effects of the invention.

Other additives mentioned above include, for example, well-known additives such as: antistatic agents, antioxidants, softeners (plasticizers), fillers, rust inhibitors, colorants (pigments, dyes), sensitizers, adhesives, reaction retarders, and crosslinking accelerators (catalysts).

Furthermore, the term "reaction retarder" refers to, for example, a component that inhibits the action of a catalyst mixed in adhesive components (I-1) to (I-4), thereby preventing unintended cross-linking reactions from occurring in the stored adhesive components (I-1) to (I-4). Examples of reaction retarders include compounds that form chelate complexes by targeting the catalyst; more specifically, compounds having two or more carbonyl groups (-C(=O)-) in one molecule.

The adhesive compositions (I-1) to (I-4) may contain only one or more other additives. When there are two or more additives, the combination and ratio of these other additives can be arbitrarily selected.

The content of other additives in adhesive compositions (I-1) to adhesive compositions (I-4) is not particularly limited; they can be selected appropriately according to their types.

[solvent]

Adhesive components (I-1) to (I-4) may also contain a solvent. By containing a solvent, the coating suitability of adhesive components (I-1) to (I-4) for the object being coated is improved.

The aforementioned solvent is preferably an organic solvent. Examples of such organic solvents include: ketones such as methyl ethyl ketone and acetone; esters (carboxylic acid esters) such as ethyl acetate; ethers such as tetrahydrofuran and dioxane; aliphatic hydrocarbons such as cyclohexane and n-hexane; aromatic hydrocarbons such as toluene and xylene; and alcohols such as 1-propanol and 2-propanol.

The adhesive components (I-1) to (I-4) may contain only one type of solvent or two or more types. When there are two or more types, the combination and ratio of those solvents can be arbitrarily selected.

The solvent content of adhesive components (I-1) to adhesive components (I-4) is not particularly limited; it can be adjusted appropriately.

○ Method for manufacturing adhesive components

Adhesive compositions, for example, can be manufactured using the same method as the previously described thermosetting protective film forming compositions, except for the difference in the types of formulations.

◇Manufacturing method of composite sheet for protective film formation

The aforementioned composite sheet for forming the protective film can be manufactured by laminating the layers in a corresponding positional relationship, and adjusting the shape of some or all of the layers as needed. The method for forming each layer is as previously described.

For example, when manufacturing support sheets, if an adhesive layer is deposited on a substrate, the aforementioned adhesive composition can be applied to the substrate and dried as needed.

Alternatively, an adhesive composition can be coated onto the release liner and dried as needed to pre-form an adhesive layer on the release liner, allowing the exposed surface of this adhesive layer to adhere to one side of the substrate. This method also allows for the deposition of an adhesive layer on the substrate. In this case, the adhesive composition is preferably coated on the release-treated surface of the release liner. Furthermore, this type of release liner can be removed at any time during the manufacturing process of the protective film forming composite sheet or during use.

Although this example illustrates the case of an adhesive layer being laminated onto a substrate, the method described above can also be applied to cases where other layers besides the adhesive layer are laminated onto the substrate.

On the other hand, for example, when a protective film is deposited on an adhesive layer already deposited on a substrate, a protective film forming component can be coated on the adhesive layer to directly form the protective film forming film. Layers other than the protective film forming film can also be formed using the same component and deposited on the adhesive layer using the same method. In this way, when a new layer (hereinafter referred to as "the second layer") is formed on any layer already deposited on the substrate (hereinafter referred to as "the first layer"), thus forming a continuous two-layer laminated structure (in other words, a laminated structure of the first and second layers), a method can be applied to the first layer to coat the composition used to form the second layer and then dried as needed.

However, it is preferable to form a continuous two-layer laminated structure by pre-forming a second layer on the release membrane using a composition for forming the second layer, and then adhering the exposed surface of the pre-formed second layer (the side opposite to the release membrane) to the exposed surface of the first layer. In this case, the composition is preferably coated on the release treatment surface of the release membrane. The release membrane can be removed as needed after forming the laminated structure.

Here, although the example given is of a protective film laminated on an adhesive layer, the laminated structure can be arbitrarily chosen, such as when a protective film is laminated on an adhesive layer to form a layer (film) other than the original protective film.

In this way, all layers other than the substrate constituting the protective film forming composite sheet can be deposited using a method that pre-forms them on the release film and then adheres them to the surface of the target layer. Therefore, layers using this method can be appropriately selected to manufacture the protective film forming composite sheet as needed.

In addition, protective film forming composite sheets are usually stored with a release film attached to the outermost layer (e.g., the protective film forming film) on the side opposite to the support sheet. Therefore, a protective film forming composite sheet with a release liner can be obtained by: coating a protective film forming component or other component used to form the outermost layer onto the release liner (preferably the release-treated surface of the release liner) and drying it as needed, thereby pre-forming the outermost layer on the release liner; and depositing the remaining layers on the exposed surface opposite to the side of that layer that contacts the release liner, maintaining the adhered state without removing the release liner.

◇Wafer Recycling Methods

One embodiment of the present invention provides a wafer regeneration method that involves attaching a protective film forming film or a protective film forming composite of the present invention to the inner surface of a wafer, and then peeling the protective film from the inner surface of the wafer, thereby making the inner surface of the wafer ready for reattaching the protective film, thus regenerating the wafer.

Regarding the wafer regeneration method of this embodiment, by using the aforementioned protective film to form a film, even in cases where the inner surface of the wafer is rough, the protective film can be peeled off normally and easily from the inner surface of the wafer, thus exhibiting superior wafer regeneration suitability.

The following wafer regeneration methods will be explained sequentially with reference to the diagrams: a wafer regeneration method in which a protective film forming film that does not constitute a protective film forming composite is attached to the inner surface of the wafer (sometimes referred to as "Regeneration Method 1" in this specification), and a wafer regeneration method in which a protective film forming film from a protective film forming composite is attached to the inner surface of the wafer (sometimes referred to as "Regeneration Method 2" in this specification).

[Regeneration Method 1]

Figures 6A to 6E are cross-sectional views illustrating one example of a wafer regeneration method and one example of a protective film reattachment method according to this embodiment. Here, the case using the protective film 13 shown in Figure 1 is used as an example of a wafer regeneration method, and regeneration method 1 will be explained.

In regeneration method 1, as shown in Figure 6A, a protective film forming film 13 is attached to the inner surface 9b of wafer 9. This shows the case where the first peel-off film 151 of the protective film forming film 13 with its own peel-off film is removed, thereby attaching the exposed first surface 13a of the protective film forming film 13 to the inner surface 9b of wafer 9. In this embodiment, the second peel-off film 152 can also be removed from the protective film forming film 13 with its own peel-off film, thereby attaching the exposed second surface 13b of the protective film forming film 13 to the inner surface 9b of wafer 9 (not shown).

In regeneration method 1, the inner surface 9b of wafer 9 is preferably a rough surface with the aforementioned recesses. When the inner surface 9b of wafer 9 is rough, the effects of forming film 13 using the protective film can be significantly achieved.

The inner surface 9b of wafer 9 is preferably ground using a grinding wheel with a rougher grit than #2000, more preferably using a grinding wheel with a rougher grit than #1500, and even more preferably using a grinding wheel with a rougher grit than #1000. In such a wafer 9, the effects of forming film 13 using the protective film can be more significantly achieved.

The attachment of the protective film 13 to the wafer 9 can be performed using known methods such as rolling.

There are no particular limitations on the adhesion conditions of the protective film forming film 13 to the wafer 9. In cases where the inner surface 9b of the wafer 9 is rough, allowing the protective film forming film 13 to embed the aforementioned recess to a greater depth, the temperature of the protective film forming film 13 during adhesion (adhesion temperature) is preferably 20°C to 100°C, the adhesion speed of the protective film forming film 13 is preferably 0.1 m/min to 2 m/min, and the pressure applied to the protective film forming film 13 during adhesion (adhesion pressure) is preferably 0.1 MPa to 0.6 MPa.

In regeneration method 1, next, as shown in FIG. 6D, the protective film forming film 13 is peeled off from the inner surface 9b of the wafer 9. For this purpose, for example, a second peeling film 152 is removed from the protective film forming film 13 already attached to the wafer 9. Then, as shown in FIG. 6B, an adhesive tape 6 is attached to the second surface 13b of the protective film forming film 13 exposed therefrom to peel off the resin film from the object to which the resin film is attached. Next, as shown in FIG. 6C, the stack of the protective film forming film 13 and the adhesive tape 6 is peeled off from the inner surface 9b of the wafer 9. For example, if the adhesive tape 6 is hardenable, and its uncracked state is soft but hardens upon hardening, the uncracked adhesive tape 6 can be attached to the protective film 13. Then, the adhesive tape 6 is hardened, and the hardened deposit of the protective film 13 and the adhesive tape 6 is peeled off from the inner surface 9b of the wafer 9. This method allows for easier peeling of the protective film 13 from the inner surface 9b of the wafer 9. In Figures 6B and 6C, both the adhesive tape and its hardened deposit are indicated by the symbol 6.

The adhesive tape 6 is not particularly limited as long as it has high adhesion to the protective film forming film 13; any known adhesive tape can be used.

When the protective film forming film 13 is attached to the inner surface 9b of the wafer 9, attachment abnormalities may occur, such as misalignment of the attachment position of the protective film forming film 13 or attachment of the protective film forming film 13 with foreign matter trapped between the inner surface 9b of the wafer 9 and the attachment surface of the protective film forming film 13 (first surface 13a in FIG. 6A). In this regard, in the recycling method 1, even if the inner surface 9b of the wafer 9 is rough, when the protective film forming film 13 is peeled off from the inner surface 9b of the wafer 9, the wafer 9 will not be damaged, and no amount of the protective film forming film 13 will remain on the inner surface 9b of the wafer 9 to the extent that it would degrade the subsequent usability of the wafer 9. Peeling can be performed normally and easily. Therefore, by configuring the inner surface 9b of the wafer 9 to allow for the reattachment of the protective film 13, the wafer 9 can be regenerated.

In cases where a portion of the protective film 13 remains on the inner surface 9b of the wafer 9 after the protective film 13 has been peeled off, in an amount sufficient to avoid degrading the subsequent usability of the wafer 9, the residue of the protective film 13 can be removed, for example, using known methods. More specifically, for example, an adhesive tape 6 or the adhesive side of an adhesive tape other than the adhesive tape 6 can be attached to the area on the inner surface 9b of the wafer 9 where the residue of the protective film 13 exists. Then, these adhesive tapes are peeled off from the inner surface 9b of the wafer 9, thereby transferring the residue of the protective film 13 from the inner surface 9b of the wafer 9 to the adhesive side of these adhesive tapes for removal.

After wafer 9 is regenerated using regeneration method 1, for example, as shown in FIG. 6E, a separately prepared protective film forming film 13, which is different from the already peeled protective film forming film, can be reattached to the inner surface 9b of the regenerated wafer 9. Although this is shown here as the case of reattaching the protective film forming film 13 having the second peel film 152, similar to the initial attachment case, the protective film forming film 13 having the first peel film 151 can also be reattached. Furthermore, the protective film forming film in the protective film forming composite can be reattached to the inner surface 9b of wafer 9 instead of the protective film forming film 13 having the peel film.

The re-attachment of the protective film forming film 13, etc., to the wafer 9 can be performed, for example, using the same method as the initial attachment of the protective film forming film 13 to the wafer 9 as previously described.

In this embodiment, by re-attaching the protective film forming film 13, a laminated film 501 comprising a wafer 9 and the protective film forming film 13 disposed on the inner surface 9b of the wafer 9 can be obtained. The same laminated film can also be obtained when using a protective film forming film other than the protective film forming film 13. Furthermore, by using a laminated film such as the laminated film 501, a target chip with a protective film can be manufactured.

[Regeneration Method 2]

Figures 7A to 7D are cross-sectional views illustrating other examples of the wafer regeneration method of this embodiment, and one example of a method for re-attaching the protective film. Here, the case using the protective film forming composite sheet 101 shown in Figure 2 is used as an example of a wafer regeneration method, and regeneration method 2 will be explained.

In recycling method 2, as shown in FIG. 7A, a protective film forming film 13 from a protective film forming composite sheet 101 is attached to the inner surface 9b of wafer 9. More specifically, a release film 15 is removed from the protective film forming film 13, and the first surface 13a of the exposed protective film forming film 13 is attached to the inner surface 9b of wafer 9. That is, the attachment of the protective film forming film 13 is performed by attaching the protective film forming composite sheet 101.

In regeneration method 2, it is also preferable that the inner surface 9b of wafer 9 is a rough surface with the aforementioned recesses. When the inner surface 9b of wafer 9 is rough, the effects of forming film 13 using the protective film can be significantly obtained.

The attachment of the protective film forming composite 101 to the wafer 9 can be performed using the same method as the attachment of the protective film forming film 13 to the wafer 9 in regeneration method 1.

The attachment conditions of the composite sheet 101 for forming the protective film toward the wafer 9 are not particularly limited, and can be the same as the attachment conditions of the protective film forming film 13 toward the wafer 9 in recycling method 1.

In regeneration method 2, next, as shown in FIG. 7C, the protective film forming film 13 is peeled off from the inner surface 9b of the wafer 9. For this purpose, for example, as shown in FIG. 7B, the protective film forming film 13 is peeled off together with the support sheet 10 from the inner surface 9b of the wafer 9; that is, the protective film forming composite sheet 101 is directly peeled off.

When the protective film forming film 13 in the protective film forming composite 101 is attached to the inner surface 9b of the wafer 9, the same attachment abnormality as that encountered in regeneration method 1 may occur. Similarly, in regeneration method 2, even when the inner surface 9b of the wafer 9 is rough, the protective film forming film 13 can be peeled off from the inner surface 9b of the wafer 9 without damaging the wafer 9, and without leaving any residue on the inner surface 9b of the wafer 9 that would degrade its future usability. Therefore, by setting the inner surface 9b of the wafer 9 to a state where a protective film forming film can be reattached, the wafer 9 can be regenerated.

In the case where a portion of the protective film 13 remains on the inner surface 9b of the wafer 9 after the protective film 13 has been peeled off, in an amount sufficient to avoid degrading the subsequent usability of the wafer 9, the residue of the protective film 13 can be removed from the inner surface 9b of the wafer 9, similar to the case of regeneration method 1.

After the wafer 9 is regenerated by regeneration method 2, for example, as shown in FIG. 7D, a protective film forming film 13, which is separately prepared from the protective film forming film that has been peeled off, can be reattached to the inner surface 9b of the regenerated wafer 9. Although this is shown as the case of reattaching the protective film forming film 13 in the protective film forming composite sheet 101, it is also possible to reattach the protective film forming film in protective film forming composite sheets other than the protective film forming composite sheet 101 (for example, the protective film forming composite sheets 102, 103, or 104 shown in FIG. 3 to 5). That is, the re-attachment of the protective film forming film 13, etc., is performed by attaching a protective film forming composite sheet, such as a protective film forming composite sheet 101.

Furthermore, a protective film forming film 13 with a release liner (e.g., a protective film forming film 13 with a second release liner 152 or a protective film forming film 13 with a first release liner 151) can be attached to the inner surface 9b of the wafer 9, instead of the protective film forming film 13 in the protective film forming composite 101.

The reattachment of the protective film forming film 13, etc., in the aforementioned protective film forming composite 101 to the wafer 9 can, for example, be performed using the same method as the initial attachment of the protective film forming film 13 to the wafer 9, as previously described.

In this embodiment, by reattaching the protective film forming film 13 to the protective film forming composite 101, a multilayer composite 401 can be obtained, consisting of a support sheet 10, a protective film forming film 13, and a wafer 9 sequentially deposited in the thickness direction of these layers. The same multilayer composite can also be obtained when using a protective film forming film other than the protective film forming film 13 in the protective film forming composite 101. Furthermore, by using multilayer composites such as the multilayer composite 401, a target chip with a protective film can be manufactured.

◇Manufacturing method of wafers with protective films (method of using protective film forming film and composite wafer for protective film forming)

The aforementioned protective film forming film and the composite sheet for forming the protective film can be used to manufacture the aforementioned wafer with a protective film.

[Manufacturing Method 1]

As a method for manufacturing a wafer with a protective film (sometimes referred to as "manufacturing method 1" in this specification) in which a protective film forming film that does not constitute a protective film forming composite is attached to the inner surface of a wafer, the following method for manufacturing a wafer with a protective film can be cited: the protective film is formed from the aforementioned protective film forming film that does not constitute the aforementioned protective film forming composite; if the aforementioned protective film forming film is hardened, the hardened form of the aforementioned protective film forming film is the aforementioned protective film; and if the aforementioned protective film forming film is non-hardened, the aforementioned protective film forming film attached to the inner surface of the aforementioned wafer is the aforementioned protective film. The method for manufacturing a wafer with a protective film includes the following steps: attaching the aforementioned protective film forming film to the inner surface of the aforementioned wafer, thereby creating a protective film forming film that is provided (layered) on the inner surface of the aforementioned wafer. The first laminate of the film or protective film is attached; after the attachment step, a lamination step of depositing a diced wafer is performed on the side of the protective film that is opposite to the wafer side, or on the side of the wafer that is opposite to the protective film side; after the lamination step, a dicing step of fabricating the wafer by dicing (cutting) the wafer; the aforementioned lamination step is followed by a first laminate of the protective film or protective film. Following the layering step, a cutting step is performed to cut the aforementioned protective film forming film or protective film; and a picking step is performed to pick up the aforementioned wafer, which has the cut protective film forming film or protective film, from the aforementioned dicing sheet; if the aforementioned protective film forming film is curable, after the aforementioned attachment step, a curing step is performed to harden the aforementioned protective film forming film, thereby forming the aforementioned protective film.

The aforementioned manufacturing method 1 may also include, between the aforementioned attaching step and the aforementioned picking step, a printing step whereby laser light is irradiated directly or through the aforementioned dicing blade onto the aforementioned protective film forming film or protective film in the aforementioned first laminate, on the protective film forming film or protective film opposite to the aforementioned wafer side, thereby printing text onto the aforementioned protective film forming film or protective film.

In cases where the aforementioned printing step precedes the aforementioned lamination step, it is preferable that in the aforementioned lamination step, the protective film forming film, or the surface of the protective film, which becomes the lamination object of the cutting sheet, is the surface on which the printing is performed in the printing step.

The aforementioned cutting disc can be a known cutting disc, or it can be the same as the aforementioned support disc.

The aforementioned layering steps can be performed using well-known methods.

In this embodiment, it is preferable to perform the aforementioned segmentation step and the aforementioned cutting step simultaneously after the aforementioned layering step, or to perform the aforementioned segmentation step followed by the aforementioned cutting step.

In this embodiment, regardless of the order of wafer dicing, protective film formation, or protective film cutting, if the operations are performed continuously without interruption by the same steps, the dicing and cutting steps are considered to be performed simultaneously.

The aforementioned segmentation and cutting steps can both be performed using known methods, in the order they are performed.

In cases where a dicing step is performed followed by a cutting step, especially when the wafer is a semiconductor wafer, wafer dicing (in other words, monolithization) can be achieved, for example, through stealth dicing (registered trademark) or laser dicing.

Stealth dicing (registered trademark) is a method as follows: First, a predetermined dicing area is defined inside a semiconductor wafer. Laser light is then focused onto this area, forming a modified layer inside the semiconductor wafer. Unlike other parts of the semiconductor wafer, this modified layer has been altered and weakened by laser light irradiation. Therefore, by applying force to the semiconductor wafer, cracks extending along both sides of the wafer are created in the modified layer, becoming the starting point for dicing the semiconductor wafer. Then, force is applied to the semiconductor wafer to dice it at the aforementioned modified layer, thus fabricating a semiconductor chip.

When the cutting step is performed after the dicing step, the cutting of the protective film can be performed, for example, by stretching the protective film in a direction parallel to the wafer attachment surface (i.e., expansion). The expanded protective film is cut along the outer periphery of the wafer. This cutting using expansion is preferably performed at a low temperature, such as -20°C to 5°C.

When performing both dicing and cutting steps simultaneously, wafer dicing and protective film formation or cutting can be achieved simultaneously through various cutting methods such as blade cutting, laser cutting using laser irradiation, or water cutting using water spray containing abrasive.

Alternatively, a semiconductor wafer with a modified layer formed by stealth dicing (registered trademark) but not yet diced, along with a protective film or protective film, can be extended using the same method as described above, thereby simultaneously dicing the semiconductor wafer and cutting the protective film or protective film.

In cases where a dicing step is performed after a cutting step, the protective film formation film or protective film can be cut without dicing the wafer by using the same methods described above for each cutting step. Subsequently, the wafer can be diced by fracture or by using the same methods described above for each cutting step.

In the aforementioned pick-up step, the wafer with the cut protective film forming film or protective film can be separated from the diced wafer by known methods such as vacuum clamping.

Manufacturing method (1) may include, in addition to the aforementioned steps of attaching, hardening, printing, laminating, dividing, cutting, and picking, other steps that are not equivalent to any of these steps.

The types of the aforementioned steps and the timing of performing them can be chosen arbitrarily depending on the purpose, without any particular limitation.

[Manufacturing Method 2]

As a method for manufacturing a wafer with a protective film (sometimes referred to as "manufacturing method 2" in this specification) in which a protective film forming composite is attached to the inner surface of a wafer, the following method for manufacturing a wafer with a protective film can be described: the protective film is formed from the aforementioned protective film forming film in the aforementioned protective film forming composite; if the aforementioned protective film forming film is hardened, the hardened form of the aforementioned protective film forming film is the aforementioned protective film; and if the aforementioned protective film forming film is non-hardened, the aforementioned protective film forming film attached to the inner surface of the aforementioned wafer is the aforementioned protective film. The method for manufacturing a wafer with a protective film includes the following steps: attaching the protective film forming film to the inner surface of the aforementioned protective film forming composite... The process includes: an attachment step where the protective film is attached to the inner surface of the wafer to create a second laminate on the inner surface of the wafer, on which the protective film forming composite is deposited; a dicing step where the wafer is diced to create a wafer after the attachment step; a cutting step where the protective film is cut after the attachment step; and a picking step where the wafer having the cut protective film is peeled off from the support sheet; if the protective film is hardenable, a hardening step where the protective film is hardened after the attachment step to form the protective film.

The aforementioned manufacturing method 2 may also, after the aforementioned attachment step, include a printing step whereby laser light is irradiated from the outside of the aforementioned protective film forming film or protective film in the aforementioned protective film forming composite sheet within the aforementioned second laminate, from the side of the aforementioned protective film forming composite sheet, thereby printing text onto the aforementioned protective film forming film or protective film.

Manufacturing method 2 is identical to manufacturing method 1, except that it uses a protective film forming composite sheet instead of a protective film forming film that does not constitute a protective film forming composite sheet, and it omits the aforementioned lamination step. Other steps different from those in manufacturing method 1 may be added as needed.

◇Manufacturing Method of Substrate Device (Use of Chips with Protective Film)

After obtaining a chip with a protective film using the above-described manufacturing method, the substrate device can be manufactured using the same method as that used in the conventional substrate device manufacturing process, except that the chip with the protective film can be used instead of a conventional chip with a protective film.

As a method for manufacturing such a substrate device, one example is a method including a flip-chip interconnect step. This flip-chip interconnect step involves electrically connecting the protruding electrodes on a protective film-coated wafer (obtained by forming a protective film using the aforementioned protective film) to connection pads on a circuit substrate.

[Implementation Example]

The present invention will now be described in more detail with specific examples. However, the present invention is not limited to the examples shown below.

[Raw materials for resin production]

The following are the formal names of the raw materials used in the manufacture of resins, as abbreviated in this embodiment and comparative example.

MA: Methyl acrylate

HEA: 2-Hydroxyethyl acrylate

2EHA: 2-Ethylhexyl acrylate

GMA: Glyceryl methacrylate

AAc: Acrylic acid

MMA: Methyl methacrylate

[Raw materials for manufacturing components for protective film formation]

The following describes the raw materials used in the manufacture of components for forming protective films.

[Polymer Component (A)]

(A)-1: An acrylic polymer copolymer (weight average molecular weight 850,000, glass transition temperature -49°C) synthesized from 2EHA (65 parts by mass), MA (14 parts by mass), GMA (5 parts by mass), AAc (1 part by mass), and HEA (15 parts by mass).

(A)-2: An acrylic polymer (weight average molecular weight 500,000, glass transition temperature -38°C) copolymerized from 2EHA (65 parts by mass), MMA (25 parts by mass), and HEA (10 parts by mass).

(A)-3: Acrylic acid copolymer (TEISANRESIN SG-P3 manufactured by Nagase ChemteX)

(A)-4: An acrylic polymer copolymerized from MA (87 parts by mass) and HEA (13 parts by mass) (weight average molecular weight 500,000, glass transition temperature 6°C)

(A)-5: An acrylic polymer copolymerized from MA (97 parts by mass) and HEA (3 parts by mass) (weight average molecular weight 500,000, glass transition temperature 9°C)

[Epoxy Resin (B1)]

(B1)-1: Bisphenol A type epoxy resin (Mitsubishi Chemical Corporation "jER828", epoxy equivalent 184 g/eq to 194 g/eq)

(B1)-2: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd., "jER834", epoxy equivalent 230 g/eq to 270 g/eq)

(B1)-3: Dicyclopentadiene-type epoxy resin (manufactured by DIC, "EPICLON HP-7200", epoxy equivalent 254g/eq to 264g/eq)

(B1)-4: Dicyclopentadiene-type epoxy resin ("XD-1000" manufactured by Nippon Kayaku Co., Ltd.), epoxy equivalent 245 g/eq to 260 g/eq)

[Thermosetting agent (B2)]

(B2)-1: Dicyandiamide (a thermally active latent epoxy resin hardener, manufactured by Mitsubishi Chemical Corporation as "DICY7")

[Hardening Accelerator (C)]

(C)-1: 2-Phenylon-4,5-Dihydroxymethylimidazol (CUREZOL 2PHZ, manufactured by Shikoku Chemical Industry Co., Ltd.)

[Fill Material (D)]

(D)-1: Silica filler (SC2050MA manufactured by Admatechs, a spherical silica filler with surface modification using epoxy compounds, with an average particle size of 0.5 μm )

[Coupler(E)]

(E)-1: An oligomeric silane coupling agent with epoxy, methyl, and methoxy groups (Shin-Etsu Chemical Co., Ltd., "X-41-1056", epoxy equivalent 280 g/eq)

[Colorant (I)]

(I)-1: Organic black pigment ("6377 Black" manufactured by Daiichi Seika Co., Ltd.)

[Implementation Example 1]

[Manufacturing of Protective Film Forming Film]

[Manufacturing of Component (III)-1 for Protective Film Formation]

Polymer component (A)-1 (25 parts by mass), epoxy resin (B1)-1 (10 parts by mass), epoxy resin (B1)-3 (5 parts by mass), thermosetting agent (B2)-1 (0.1 parts by mass), curing accelerator (C)-1 (0.1 parts by mass), filler (D)-1 (57.5 parts by mass), coupling agent (E)-1 (0.3 parts by mass), and colorant (I)-1 (2 parts by mass) were dissolved or dispersed in methyl ethyl ketone and stirred at 23°C to obtain a thermosetting protective film forming composition (III)-1 with a total concentration of 60% by mass for all components except the solvent. The amounts of components other than methyl ethyl ketone shown here are all solvent-free target amounts.

[Manufacturing of Protective Film Forming Film]

A protective film forming component (III)-1, obtained above, is formed by applying a single-sided polysiloxane-treated peel film (second peel film, "SP-PET502150" manufactured by Lintec Corporation, with a thickness of 50 μm ) to the peeled side of the aforementioned peel film and drying it at 100 ° C for 2 minutes.

Furthermore, the exposed surface of the protective film forming film without the second release membrane is bonded to the release treatment surface of the release membrane (the first release membrane, "SP-PET381031" manufactured by Lintec Corporation, with a thickness of 38 μm ) under the conditions of a bonding speed of 2 m/min, a bonding temperature of 60°C, and a bonding pressure of 0.5 MPa, thereby obtaining a protective film forming film with a release membrane. This protective film forming film with a release membrane is composed of a protective film forming film, a first release membrane disposed on one side of the aforementioned protective film forming film, and a second release membrane disposed on the other side of the aforementioned protective film forming film.

[Evaluation of Protective Film Formation]

[Measurement of Surface Roughness (Ra)]

The first release film is removed from the protective film forming film with the release film obtained above. Then, the surface roughness (Ra) of the exposed surface of the protective film forming film (the surface facing the wafer; the first surface) is measured according to ANSI/ASME B46.1 using an optical interferometry surface shape measuring device (WYKO NT1100 manufactured by Veeco Metrology Group) under the following measurement conditions. The results are shown in Table 1.

[Testing Conditions]

Magnification of the lens: 10x

Built-in lens magnification: 1x

Mode: PSI (Phase-Shifting Interferometry)

Measurement area: 0.35 ^mm²

[Determination of strain (0.1 N/ ^mm² ) and strain (0.6 N/ ^mm² )]

Using the five protective film forming membranes with peelable membranes obtained above, while removing the first or second peelable membrane of these protective film forming membranes, the exposed surfaces of the protective film forming membranes are sequentially laminated together to create a laminate consisting of a second peelable membrane, five protective film forming membranes (total thickness 200 μm ), and the second peelable membrane. Then, slices with a width of 15 mm are cut from this laminate.

Next, the two outermost layers of the second exfoliating membrane were removed from this section, and the resulting laminate was used as a test piece.

For the obtained test piece (200 μm thick), a pair (2) of clamps were installed at 30 mm intervals to hold the test piece at two points. Then, a tensile test was performed using a precision universal testing machine (Shimadzu Autograph AG-IS). The test piece was stretched at a speed of 1000 mm/min between the two clamps in a direction parallel to the surface of the test piece. This tensile test ended when the strain of the test piece reached 350%. The strain (0.1 N/ ^mm² ) and strain (0.6 N/ ^mm² ) were then measured. The results are shown in Table 1.

[Evaluation of Wafer Recyclability]

The protective film forming film is formed by grinding the surface that becomes the attachment surface (hereinafter referred to as the "inner surface") with #340, which prepares a silicon wafer with a diameter of 200 mm and a thickness of 350 μm that is rougher than usual.

From the protective film with a release membrane obtained above, cut out a protective film with a diameter 5 mm smaller than the diameter of the silicon wafer. Then remove the first release membrane from the protective film forming membrane, exposing one side of the protective film forming membrane.

Next, with the exposed surface (first surface) of the protective film facing the inner surface (grinding surface) of the silicon wafer, the protective film is heated to 70°C and then adhered to the inner surface of the silicon wafer using a roller at a bonding speed of 0.3 m/min and a bonding pressure of 0.3 MPa. At this point, the protective film and the silicon wafer are positioned concentrically.

Next, after the protective film is applied, the second peeling film is removed. On the exposed side of the protective film formed therefrom (the side opposite to the side facing the silicon wafer; the second side), a "D-841" (hereinafter referred to as "peeling tape") manufactured by Lintec Corporation is applied as a peeling tape using a scraper. Then, the peeling tape is irradiated with ultraviolet light at an illuminance of 230 mW/ ^cm² and a light intensity of 190 mJ/ ^cm² to harden the peeling tape.

Next, the protective film and the deposits on the stripping layer are peeled off from the inner surface of the silicon wafer to determine the extent of protective film residue on the inner surface.

Secondly, even if only a small amount of protective film remains on the inner surface of the silicon wafer, a peeling tape (Lintec's "D-841") is attached to the corresponding area on the inner surface. The peeling tape is then irradiated with ultraviolet light under the same conditions to harden it. Then, the peeling tape is peeled off from the inner surface of the silicon wafer to attempt to remove any remaining protective film. The extent of the remaining protective film on the inner surface is then assessed.

Next, the regeneration suitability of the wafers from which the protective film was formed was evaluated according to the following criteria. The results are shown in Table 1.

[Evaluation Criteria]

A: No protective film residue was observed on the inner surface of the wafer, so there is no need to apply a release tape.

B1: Residues of the protective film formation are observed on the inner surface of the wafer, but the area of this region is less than 10% of the total inner surface area of the wafer. These residues can be completely removed using a reattached peel-off tape.

B2: Residues of the protective film formation layer were observed on the inner surface of the wafer. Although this area accounts for less than 10% of the total inner surface area of the wafer, the reattached peeling tape was unable to completely remove the aforementioned residues.

C1: Residues of the protective film formation are observed on the inner surface of the wafer. Although this area accounts for more than 10% to less than 40% of the total inner surface area of the wafer, the aforementioned residues can be completely removed by reattaching a peel-off tape.

C2: Residues of the protective film formation layer are observed on the inner surface of the wafer, and this area accounts for more than 10% to less than 40% of the total inner surface area of the wafer. The reattached peeling tape was unable to completely remove these residues.

D: Residues of the protective film formation were observed on the inner surface of the wafer, and this area accounted for more than 40% to less than 80% of the total inner surface area of the wafer.

E: Residues of the protective film formation were observed on the inner surface of the wafer, and this area accounts for more than 80% of the total inner surface area of the wafer.

[Manufacturing and Evaluation of Protective Film Formation]

[Examples 2 to 7, Comparative Examples 1 to 3]

The protective film was manufactured and evaluated using the same method as in Example 1, except that at least one of the types and amounts of the formulation components was changed, with the composition and content of the protective film forming film as shown in Table 1 or Table 2. The results are shown in Table 1 or Table 2.

The results above clearly show that the regeneration suitability of the wafers forming the protective film is good in Examples 1 to 7. Furthermore, in Examples 1 to 7, no silicon wafer damage was observed when evaluating the regeneration suitability of the wafers forming the protective film.

In Examples 1 to 7, the surface roughness (Ra) of the protective film forming the surface facing the wafer is 43 nm or less, exhibiting low unevenness. Then, the strain (0.1 N/ ^mm² ) of the aforementioned test piece is 0.7% or more, and the strain (0.6 N/ ^mm² ) of the aforementioned test piece is 15.2% or less. The aforementioned test pieces in Examples 1 to 7 did not break until the aforementioned strain reached 350% (i.e., until the end of the aforementioned tensile test).

In contrast, the regeneration suitability of the wafers forming the protective film in Comparative Examples 1 to 3 was significantly worse. However, in Comparative Examples 1 to 3, no silicon wafer damage was observed when evaluating the regeneration suitability of the wafers forming the protective film.

In Comparative Examples 1 to 3, the surface roughness (Ra) of the protective film forming the surface facing the wafer was 42 nm or less, exhibiting the same low unevenness as in Examples 1 to 7. However, in Comparative Examples 1 to 2, the strain (0.1 N/ ^mm² ) of the aforementioned test piece was 0.2% or less, while in Comparative Example 3, the strain (0.6 N/ ^mm² ) of the aforementioned test piece was 330%. The aforementioned test pieces in Comparative Examples 1 to 3 did not break until the aforementioned strain reached 350%.

Furthermore, it was confirmed that the protective film forming films of Examples 1 to 7 and Comparative Examples 1 to 3 could all be normally formed into the target protective film through thermosetting.

[Industry Availability]

This invention can be used to manufacture various substrate devices, primarily semiconductor devices.

13: Protective film forming membrane 13a: One side of the protective film forming membrane (side 1) 13b: The other side of the protective film forming membrane (side 2) 151: First peeling membrane 152: Second peeling membrane

Claims (4)

A protective film is formed, which is thermosetting; when the aforementioned protective film is subjected to a tensile test, the strain is more than 0.5% when the stress is initially 0.1 N/ ^mm² , and more than 0.5% when the stress is initially 0.6 N/mm². The strain at ^2° C is less than 200%; the aforementioned tensile test involves holding the test piece, which is a multi-piece laminate of the aforementioned protective film forming film, at two 30mm intervals, and stretching the test piece at a speed of 1000mm/min in a direction parallel to the surface of the test piece between the two intervals. The stress generated in the test piece and the strain of the test piece in the tensile direction are measured; the aforementioned protective film forming film contains polymer component (A), epoxy resin (B1), thermosetting agent (B2), and filler (D); the content of the aforementioned polymer component (A) in the aforementioned protective film forming film is relative to the total content of the aforementioned protective film forming film. The proportion of the amount is 10% to 85% by mass; in the aforementioned protective film forming film, relative to the content of the aforementioned epoxy resin (B1) 100 parts by mass, the content of the aforementioned thermosetting agent (B2) is 0.1 parts by mass to 100 parts by mass; in the aforementioned protective film forming film, relative to the total content of the aforementioned polymer component (A), the aforementioned epoxy resin (B1) and the aforementioned thermosetting agent (B2) 100 parts by mass, the total content of the aforementioned epoxy resin (B1) and the aforementioned thermosetting agent (B2) is 10 parts by mass to 70 parts by mass; in the aforementioned protective film forming film, the proportion of the content of the aforementioned filler (D) relative to the total mass of the aforementioned protective film forming film is 15% by mass to 70% by mass. The protective film formed as described in claim 1, wherein in the aforementioned tensile test, the aforementioned test piece does not break until the aforementioned strain becomes 350%. A composite sheet for forming a protective film comprises: a support sheet and a protective film forming film disposed on one side of the support sheet; the protective film forming film is the protective film forming film as described in claim 1 or 2. A wafer regeneration method involves attaching a protective film forming film as described in claim 1 or 2, or a protective film forming composite as described in claim 3, to the inner surface of a wafer, and then peeling the protective film forming film off the inner surface of the wafer, thereby making the inner surface of the wafer suitable for attaching the protective film forming film again, thus regenerating the wafer.