WO2025154795A1 - Adhesive tape - Google Patents

Abstract

The purpose of the present invention is to provide an adhesive tape which is capable of accurately suppressing or preventing the occurrence of breakage in the adhesive tape when a substrate such as a semiconductor wafer stuck on the adhesive tape is cut into individual pieces in the thickness direction by means of irradiation of a laser beam. An adhesive tape 100 according to the present invention includes a base material 4 and an adhesive layer 2. The adhesive tape 100 is used when a substrate is cut into pieces, in the thickness direction, so as to form a plurality of components by irradiating the substrate with a laser beam in a state where the substrate is fixed on the adhesive layer 2, and subsequently each component is separated from the adhesive layer 2. The base material 4 has a weight loss rate from room temperature to 420°C in the TG curve obtained by simultaneous thermogravimetry differential thermal analysis that is 50% or less.

Description

Adhesive tape

The present invention relates to an adhesive tape used to temporarily attach substrates and components.

In response to the increasing sophistication of electronic devices in recent years and the expansion into mobile applications, there is a growing demand for higher density and integration of semiconductor devices, leading to the trend toward larger capacity and higher density IC packages.

The manufacturing method of these semiconductor devices is, for example, to first apply an adhesive tape to a semiconductor substrate (semiconductor wafer) as a substrate. Then, a dicing process using a laser beam is performed while fixing the periphery of the semiconductor substrate with a wafer ring. In the dicing process, a laser beam is irradiated onto the semiconductor substrate to cut the semiconductor substrate in the thickness direction, thereby cutting and separating (singling) the semiconductor substrate into individual semiconductor elements (semiconductor chips). Next, an expanding process is performed in which the adhesive tape is stretched radially using a wafer ring to form gaps between adjacent semiconductor elements. Then, a pick-up process is performed in which the diced semiconductor elements are picked up while being pushed up by a needle. Next, the picked-up semiconductor elements are transferred to a mounting process for mounting them on a metal lead frame or substrate (e.g., a tape substrate, an organic hard substrate, etc.). In the mounting process, the picked-up semiconductor elements are adhered to a lead frame or substrate via, for example, an underfill material, and then the semiconductor elements are sealed on the lead frame or substrate with a sealing part to manufacture a semiconductor device.

In such a manufacturing method for semiconductor devices that uses a laser beam to dice a semiconductor substrate, an adhesive tape (dicing tape) is used to temporarily fix the semiconductor substrate (semiconductor wafer) and the semiconductor elements that are separated from the semiconductor substrate (see, for example, Patent Document 1).

This adhesive tape generally has a base material (film base material) and an adhesive layer formed on this base material, with the semiconductor substrate fixed to the adhesive layer. As in the manufacturing method of the semiconductor device described above, with an adhesive tape having this configuration, after the dicing process in which the semiconductor substrate is diced by irradiating it with a laser beam, an expanding process in which the adhesive tape is stretched radially is performed. This forms a gap between adjacent semiconductor elements. In this state, a pick-up process is performed in which the semiconductor elements are picked up.

Here, in the dicing process described above, when the semiconductor substrate is cut in the thickness direction by irradiation with a laser beam, the focus of the laser beam irradiated onto the semiconductor substrate is adjusted to the upper part of the semiconductor substrate or midway through the thickness direction of the semiconductor substrate. When the semiconductor substrate is thin, the laser beam is often focused on the upper part of the semiconductor substrate. This causes the semiconductor substrate to be cut along the thickness direction. At this time, due to the short distance between the focus of the laser beam and the adhesive tape, unintentional breakage occurs in the adhesive tape. As a result, in the expanding process and pick-up process following the dicing process, the semiconductor element cannot be positioned in the predesigned position, and therefore there is a problem in that the semiconductor element cannot be picked up with excellent precision.

Furthermore, this problem is not limited to cases where semiconductor elements are obtained as components by cutting a semiconductor substrate (semiconductor wafer) in the thickness direction as a substrate, but also occurs in cases where various substrates such as glass substrates, ceramic substrates, resin material substrates, and metal material substrates are cut in the thickness direction (divided into individual pieces), and then the individual pieces are obtained by picking up the individual pieces while the adhesive tape is stretched radially.

JP 2002-192370 A

The object of the present invention is to provide an adhesive tape that is used to detach components from the adhesive tape by sequentially going through an expanding process to stretch the adhesive tape and a pick-up process to pick up the components after a dicing process in which a substrate such as a semiconductor wafer attached to the adhesive tape is cut in the thickness direction by irradiation with a laser beam to separate the components into individual pieces, and that can accurately suppress or prevent breakage of the adhesive tape when the substrate is divided into individual pieces.

These objects can be achieved by the present invention described in (1) to (10) below.
(1) An adhesive tape comprising a base material and an adhesive layer containing an adhesive base resin as a main material and laminated on one side of the base material, the adhesive tape being used for cutting the substrate in its thickness direction and dividing the substrate into individual components by irradiating the substrate with a laser beam while the substrate is fixed on the adhesive layer, and then detaching each of the components from the adhesive layer,
The adhesive tape is characterized in that the substrate has a weight loss rate of 50% or less from room temperature to 420° C. in a TG curve obtained by simultaneous differential thermal and thermogravimetric measurement in accordance with JIS K 0129.

(2) The adhesive tape according to (1) above, wherein the tensile modulus of the substrate at 23°C is 200 MPa or less.

(3) The adhesive tape according to (1) or (2) above, in which the substrate contains a polyolefin resin as a main material.

(4) An adhesive tape according to any one of (1) to (3) above, in which the polyolefin resin is a polyethylene resin.

(5) An adhesive tape according to any one of (1) to (4) above, in which the polyethylene resin mainly contains a component whose specific gravity is 0.94 or less.

(6) An adhesive tape according to any one of (1) to (5) above, in which the base resin is an acrylic resin.

(7) The adhesive tape according to any one of (1) to (6) above, wherein the adhesive layer further contains a curable resin that is cured by the application of energy, and is configured such that the adhesive strength of the adhesive layer to the substrate and the component is reduced by the application of energy.

(8) An adhesive tape according to any one of (1) to (7) above, in which the substrate has a thickness of 30 μm or more and 300 μm or less.

(9) An adhesive tape according to any one of (1) to (8) above, in which the adhesive layer has a thickness of 5 μm or more and 30 μm or less.

(10) The adhesive tape according to any one of (1) to (9) above, configured so that the removal of the component from the adhesive layer is achieved by pulling the component from the opposite side of the substrate while pushing the component up from the substrate side while stretching the adhesive tape in the planar direction.

According to the present invention, a substrate such as a semiconductor wafer attached to an adhesive tape is cut in the thickness direction by irradiation with a laser beam to separate it into individual pieces. After a dicing process in which components such as semiconductor chips are formed on the adhesive tape, an expanding process in which the adhesive tape is stretched and a pick-up process in which the components are picked up are sequentially performed. This makes it possible to precisely suppress or prevent breakage of the adhesive tape used to detach components from the adhesive tape when the substrate is separated into individual pieces. Therefore, the pick-up of components in the pick-up process can be performed with excellent precision.

FIG. 1 is a vertical sectional view showing an example of a semiconductor device manufactured using the pressure-sensitive adhesive tape of the present invention. FIG. 2 is a vertical sectional view for illustrating a method for manufacturing the semiconductor device shown in FIG. 1 using the adhesive tape of the present invention. FIG. 3 is a vertical sectional view for illustrating a method for manufacturing the semiconductor device shown in FIG. 1 using the adhesive tape of the present invention. FIG. 4 is a vertical sectional view for illustrating a method for manufacturing the semiconductor device shown in FIG. 1 using the adhesive tape of the present invention. FIG. 5 is an enlarged cross-sectional view showing a semiconductor chip formed by cutting a semiconductor substrate in its thickness direction by irradiation with a laser beam, the semiconductor chip being located in an area [A] enclosed by a dotted line in FIG. FIG. 6 is a longitudinal sectional view showing an embodiment of the pressure-sensitive adhesive tape of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The pressure-sensitive adhesive tape of the present invention will now be described in detail with reference to preferred embodiments shown in the accompanying drawings.
First, prior to describing the pressure-sensitive adhesive tape of the present invention, an example of a semiconductor device manufactured using the pressure-sensitive adhesive tape of the present invention will be described.

<Semiconductor Device>
Fig. 1 is a longitudinal sectional view showing an example of a semiconductor device manufactured using the pressure-sensitive adhesive tape of the present invention. In the following description, the upper side in Fig. 1 is referred to as "upper" and the lower side is referred to as "lower". In addition, in each drawing referred to in this specification, the dimensions in the left-right direction and/or thickness direction are exaggerated and significantly differ from the actual dimensions.

The semiconductor device 10 shown in FIG. 1 has a semiconductor chip 20 (semiconductor element), an interposer 30 (substrate) that supports the semiconductor chip 20, a plurality of conductive bumps 70 (terminals), and a molded portion 17 (sealing portion) that seals the semiconductor chip 20.

The interposer 30 is an insulating substrate, and is made of various resin materials, such as polyimide, epoxy, cyanate, bismaleimide triazine (BT resin), etc. The planar shape of the interposer 30 is usually a quadrangle, such as a square or a rectangle.

On the top surface (one surface) of the interposer 30, terminals 41 made of a conductive metal material such as copper are provided in a predetermined shape.

In addition, the interposer 30 has multiple vias (through holes) (not shown) formed through it in its thickness direction.

Each bump 70 has one end (upper end) electrically connected to a part of the terminal 41 through each via, and the other end (lower end) protrudes from the lower surface (other surface) of the interposer 30.

The portion of the bump 70 that protrudes from the interposer 30 is approximately spherical (ball-shaped).

The bumps 70 are primarily made of solder, silver solder, copper solder, or phosphorus copper solder.

Furthermore, a terminal 41 is formed on the interposer 30. The terminal 21 of the semiconductor chip 20 is electrically connected to this terminal 41 via a connection portion 81.

In this embodiment, as shown in FIG. 1, the terminals 21 are configured to protrude from the surface formed on the semiconductor chip 20, and the terminals 41 are also configured to protrude from the interposer 30.

The gap between the semiconductor chip 20 and the interposer 30 is filled with an underfill material made of various resin materials, and the hardened underfill material forms a sealing layer 80. This sealing layer 80 has the function of improving the bonding strength between the semiconductor chip 20 and the interposer 30, and the function of preventing the intrusion of foreign matter, moisture, etc. into the gap.

Furthermore, a molded portion 17 is formed on the upper side of the interposer 30 so as to cover the semiconductor chip 20 and the interposer 30. The molded portion 17 is made of a hardened semiconductor sealing material (sealant). This seals the semiconductor chip 20 within the semiconductor device 10, preventing the intrusion of foreign matter, moisture, etc. into the semiconductor chip 20.

1, the semiconductor chip 20 (semiconductor element) has a semiconductor chip body 23 (semiconductor element body) and terminals 21 protruding from the lower surface side of the semiconductor chip body 23. The semiconductor chip body 23 has a circuit (not shown) built in on its upper surface side, and is mainly made of a semiconductor material such _as Si, SiC, GaN, GaAs, or _Ga2O3 .

The semiconductor device 10 and semiconductor chip 20 having such a configuration are manufactured, for example, by a semiconductor device manufacturing method using adhesive tape as follows.

<Method of Manufacturing Semiconductor Device>
Figures 2 to 4 are longitudinal sectional views for explaining a method for manufacturing the semiconductor device shown in Figure 1 using the adhesive tape of the present invention, and Figure 5 is an enlarged sectional view showing a semiconductor chip formed by cutting a semiconductor substrate in the thickness direction by irradiation with a laser beam, located in the area [A] surrounded by a dotted line in Figure 2. In the following description, the upper side in Figures 2 to 5 will be referred to as "upper" and the lower side will be referred to as "lower". In addition, in each of the drawings referred to in this specification, the dimensions in the left-right direction and/or thickness direction are exaggerated and significantly differ from the actual dimensions.

[1A] First, prepare an adhesive tape 100 (dicing tape) composed of a laminate having a base material 4 and an adhesive layer 2 laminated on the upper surface of the base material 4. Next, as shown in FIG. 2(a), a semiconductor substrate 7 (semiconductor wafer) is placed on the adhesive layer 2 at a position corresponding to the center 122, and then lightly pressed. This causes the semiconductor substrate 7 to be laminated (attached) to the adhesive tape 100.

In this semiconductor substrate 7, circuits that will be included in the semiconductor chips 20 formed by singulation are formed in advance. A plurality of these circuits are built into the semiconductor substrate 7 so that the plurality of semiconductor chips 20 are arranged in a grid pattern. Therefore, the individual semiconductor chips 20 are obtained by cutting the semiconductor substrate 7 into a grid pattern in a plan view so that each circuit is independent. The lines along which the semiconductor substrate 7 should be cut into a grid pattern are called the planned cutting lines. Therefore, the planned cutting lines are formed in a grid pattern (matrix pattern) in the vertical and horizontal directions of the semiconductor substrate 7 when the semiconductor substrate 7 is viewed in a plan view, corresponding to the circuits of the semiconductor chips 20 arranged in a grid pattern in the semiconductor substrate 7.

[2A] Next, as shown in FIG. 2(b), the adhesive tape 100 with the semiconductor substrate 7 laminated thereon is placed on the dicer table 250.

[3A] Next, the outer periphery 121 of the adhesive layer 2 is fixed with a wafer ring 9. After that, the semiconductor substrate 7 as a substrate is cut (diced) in the thickness direction by irradiation with a laser beam 151 by a light irradiator 150 (see FIG. 2(c)). Then, the cutting in the thickness direction of the semiconductor substrate 7 by irradiation with this laser beam 151 is performed along the planned cutting lines of the semiconductor substrate 7, i.e., in a grid pattern.

As a result, the semiconductor substrate 7 is divided into individual pieces corresponding to the positions where the semiconductor chips 20 are fabricated. As a result, as shown in FIG. 2(d), a plurality of divided semiconductor chips 20 are formed as parts in a state where they are adhered to the adhesive layer 2 on the adhesive tape 100 (dividing process).

In this case, the adhesive tape 100 has a cushioning effect and prevents cracks, chips, etc., when the semiconductor substrate 7 is cut.

In addition, when cutting the semiconductor substrate 7 by irradiating the laser beam 151 using the light irradiator 150, the laser beam 151, which has a wavelength that is absorbed by the semiconductor substrate 7, is focused on the upper part of the semiconductor substrate 7 or midway along the thickness direction of the semiconductor substrate 7, and preferably, this focus is moved from the upper surface side of the semiconductor substrate 7 toward the lower surface side. This ensures that the semiconductor substrate 7 can be singulated.

Furthermore, the laser beam 151 irradiated by the light irradiator 150 is not particularly limited as long as it is capable of cutting the semiconductor substrate 7 along the thickness direction by irradiating the semiconductor substrate 7 with the laser beam 151. However, as shown in FIG. 5, the laser beam 151 is preferably a pulsed laser beam. When the laser beam 151 is a pulsed laser beam, it is possible to appropriately suppress or prevent debris from adhering to the edge of the semiconductor chip 20 formed by cutting the semiconductor substrate 7 in the thickness direction.

In this specification, the cutting of the semiconductor substrate 7 by irradiation with the laser beam 151 includes the case where the semiconductor substrate 7 is cut based on being heated and melted at the focus of the laser beam 151. In addition, for example, the case where the process shown below is followed may also be referred to as the cutting. That is, the case where the semiconductor substrate 7 is modified at the focus of the laser beam 151 based on the occurrence of cracks or a change in the refractive index in the semiconductor substrate 7, a modified layer (modified region) is formed in the semiconductor substrate 7, and then an external force is applied to the semiconductor substrate 7 with this modified layer formed, causing a break in the modified layer, and the semiconductor substrate 7 is cut may also be referred to as the cutting.

In this way, in this step [3A], while the semiconductor substrate 7 is stacked on the adhesive tape 100, the semiconductor substrate 7 is irradiated with the laser beam 151 to cut (diced) the semiconductor substrate 7 in the thickness direction to obtain semiconductor chips 20 into which the semiconductor substrate 7 is separated. By using the adhesive tape 100, it is possible to accurately suppress or prevent breakage of the adhesive tape 100 caused by going through this step [3A]. Furthermore, the expanding of the adhesive tape 100 in the subsequent step [5A] and the pick-up of the semiconductor chips 20 in the subsequent step [6A] can be performed with excellent precision. A detailed explanation of this will be given later.

[4A] Next, as shown in FIG. 3(a), the adhesive tape 100 on which the singulated semiconductor chips 20 are laminated (attached) is placed on the pickup table 200 with the outer periphery 121 of the adhesive layer 2 fixed by the wafer ring 9. Thereafter, the adhesive layer 2 is irradiated with energy rays via the substrate 4, thereby reducing the adhesive force of the adhesive layer 2 to the semiconductor chips 20.

In addition, examples of the energy beam include ultraviolet light, electron beams, particle beams such as ion beams, and the like, or two or more of these energy beams may be combined. Among these, it is particularly preferable to use ultraviolet light. The ultraviolet light can efficiently reduce the adhesion of the adhesive layer 2 to the semiconductor chip 20.

Note that the reduction in adhesive strength to the semiconductor chip 20 by irradiating the adhesive layer 2 with energy rays may be performed prior to the expanding step, as in step [5A], or may be performed after the expanding step. Furthermore, irradiation with energy rays is one example of a method for imparting energy, and energy may be imparted by other methods.

[5A] Next, while maintaining the adhesive layer 2 fixed at its outer periphery 121 by the wafer ring 9 on the pickup table 200, the center 210 is pushed upward against the outer periphery 220 of the pickup table 200. As a result, the adhesive tape 100 is expanded radially along its surface. This forms gaps 25 with a fixed distance between the individual semiconductor chips 20 (see FIG. 3(b)).

[6A] Next, with the gap 25 formed through step [5A], the semiconductor chip 20 is picked up by suction using a vacuum collet or air tweezers (pick-up step; see Figure 3(c)).

The semiconductor chip 20 can be picked up as follows. After the adhesive tape 100 is expanded radially in step [5A], a needle (not shown) provided on the pickup table 200 is protruded from the pickup table 200 in the thickness direction. As a result, the semiconductor chip 20 attached to the adhesive tape 100 is pushed up using the needle, and the semiconductor chip 20 is picked up in a state in which it can be easily peeled off from the adhesive tape 100, as shown in FIG. 3(c). In other words, the semiconductor chip 20 can be detached from the adhesive layer 2 by pulling out the semiconductor chip 20 (component) from the opposite side of the substrate 4 while pushing it up from the substrate 4 side while the adhesive tape 100 is stretched in the planar direction.

By going through the above steps [1A] to [6A], the individual semiconductor chips 20 are separated from the semiconductor substrate 7 using the adhesive tape 100.

[7A] Next, the picked up semiconductor chip 20 is transferred from the vacuum collet or air tweezers to a mounting probe or the like. Thereafter, as shown in FIG. 4(a), the terminals 21 of the semiconductor chip 20 face the terminals 41 of the interposer 30 via the solder bumps 85 provided on the terminals 41, and the semiconductor chip 20 is placed on the interposer 30. That is, the semiconductor chip 20 (semiconductor element) is placed on the interposer 30 (substrate) with the surface on which the terminals 21 of the semiconductor chip 20 are formed facing down.

[8A] Next, as shown in FIG. 4(b), the interposer 30 and the semiconductor chip 20 are brought close to each other while the solder bumps 85 interposed between the terminals 21 and 41 are heated.

As a result, the molten solder bump 85 comes into contact with both the terminal 21 and the terminal 41, and by cooling in this state, the connection portion 81 is formed. As a result, the terminal 21 and the terminal 41 are electrically connected via the connection portion 81 (see FIG. 4(c)).

[9A] Next, an underfill material (sealing material) made of various resin materials is filled into the gap formed between the semiconductor chip 20 and the interposer 30. The underfill material is then cured to form a sealing layer 80 made of the cured underfill material (see FIG. 4(d)).

[10A] Next, a molded portion 17 (sealing portion) is formed on the upper side of the interposer 30 so as to cover the semiconductor chip 20 and the interposer 30. This seals the semiconductor chip 20 with the interposer 30 and the molded portion 17. In addition, a bump 70 is formed so as to protrude from the lower side of the interposer 30 and is electrically connected to a part of the terminal 41 through a via provided in the interposer 30 (see FIG. 4(e)).

Here, sealing with the molded portion 17 can be performed, for example, as follows. First, a molding die is prepared that has an internal space corresponding to the shape of the molded portion 17 to be formed. Powdered semiconductor encapsulation material is filled into this internal space so as to cover the semiconductor chip 20 and interposer 30 that are placed within the internal space. Then, in this state, the semiconductor encapsulation material is heated to harden it, resulting in a hardened semiconductor encapsulation material. This completes sealing with the molded portion 17.

The semiconductor device 10 can be obtained by the semiconductor device manufacturing method having the above-mentioned steps. More specifically, after carrying out the steps [1A] to [10A], the steps [6A] to [10A] are repeatedly carried out, whereby multiple semiconductor devices 10 can be manufactured in one batch from a single semiconductor substrate 7.

The present invention is applied to the adhesive tape 100 (dicing tape) used in the manufacturing method of the semiconductor device described above. The adhesive tape 100 will be described below.

<Adhesive Tape 100>
Fig. 6 is a longitudinal sectional view showing an embodiment of the pressure-sensitive adhesive tape of the present invention. In the following description, the upper side in Fig. 6 is referred to as "upper" and the lower side is referred to as "lower". In addition, in each drawing referred to in this specification, the dimensions in the left-right direction and/or thickness direction are exaggerated and significantly different from the actual dimensions.

In the manufacturing method of the semiconductor chip 20 as described above, when a conventional adhesive tape is used instead of the adhesive tape 100, the following problem occurs. Specifically, in the step [3A], when the semiconductor substrate 7 is irradiated with the laser beam 151 to cut (diced) the semiconductor substrate 7 in the thickness direction to obtain the individual semiconductor chips 20 from the semiconductor substrate 7, breakage occurs in the conventional adhesive tape. Therefore, in the expanding of the conventional adhesive tape in the step [5A] subsequent to the step [3A], and in the picking up of the semiconductor chip 20 in the step [6A], the semiconductor chip 20 cannot be positioned in the pre-designed position, and as a result, there is a problem that the picking up of the semiconductor chip 20 cannot be performed with excellent precision.

Here, in step [3A], when the semiconductor substrate 7 is cut (diced) in the thickness direction by irradiating the semiconductor substrate 7 with the laser beam 151, the focus of the laser beam 151 irradiated to the semiconductor substrate 7 is adjusted to the top of the semiconductor substrate 7 or midway through the thickness direction of the semiconductor substrate 7, thereby cutting the semiconductor substrate 7 along the thickness direction. At this time, due to the short distance between the focus of the laser beam 151 and the conventional adhesive tape, unintentional breakage occurs in the conventional adhesive tape.

In contrast, in the present invention, the substrate 4 of the adhesive tape 100 (adhesive tape of the present invention) is a substrate whose weight loss rate from room temperature (25°C) to 420°C in the TG curve of the substrate 4 obtained by simultaneous differential thermal and thermogravimetric measurement in accordance with JIS K 0129 is 50% or less.

In this way, by selecting a substrate having a weight reduction rate of 50% or less as the substrate 4, even if the laser beam 151 is irradiated onto the semiconductor substrate 7 in the step [3A] to cut the semiconductor substrate 7 in the thickness direction and the laser beam 151 is focused midway through the thickness direction of the semiconductor substrate 7, the breakage is limited to the adhesive layer 2 of the adhesive tape 100, and the occurrence of breakage in the substrate 4 can be appropriately suppressed or prevented (see FIG. 5). Also, even if the laser beam 151 is focused on the upper part of a thin semiconductor substrate 7 (e.g., a semiconductor substrate 7 having a thickness of 100 μm or less), the occurrence of breakage in the substrate 4 can be appropriately suppressed or prevented.

Therefore, in the expanding of the adhesive tape 100 in step [5A], which is a process subsequent to step [3A], and in the picking up of the semiconductor chip 20 in step [6A], the semiconductor chip 20 can be accurately positioned in a pre-designed position, so that the picking up of the semiconductor chip 20 can be performed with excellent precision.

The adhesive tape 100 to which the adhesive tape of the present invention is applied as described above is composed of a laminate including a sheet-like substrate 4 containing a resin material and an adhesive layer 2 laminated on the upper surface (one surface) of the substrate 4. The substrate 4 and adhesive layer 2 will be described below.

The adhesive tape 100 has a function of reducing the adhesiveness of the adhesive layer 2 to the semiconductor substrate 7 and the semiconductor chip 20 on the adhesive layer 2 by applying energy to the adhesive layer 2. Methods of applying energy to the adhesive layer 2 include irradiating the adhesive layer 2 with energy rays and heating the adhesive layer 2. Among these, the method of irradiating the adhesive layer 2 with energy rays is preferably used because the semiconductor chip 20 does not need to undergo unnecessary thermal history. Therefore, in the following, a configuration in which the adhesive layer 2 has a reduced adhesiveness due to irradiation with energy rays will be described as a representative example.

<Base material 4>
The substrate 4 is mainly made of a resin material, has a sheet shape, and has a function of supporting the adhesive layer 2 provided on the substrate 4. The substrate 4 is also configured to realize elongation of the adhesive tape 100 in the planar direction in the step [5A].

In addition, in the present invention, as described above, the weight loss rate of the substrate 4 from room temperature (25°C) to 420°C in the TG curve obtained by simultaneous differential thermal and thermogravimetric measurement in accordance with JIS K 0129 is 50% or less. Therefore, even if the laser beam 151 is focused midway through the thickness direction of the semiconductor substrate 7 in order to cut the semiconductor substrate 7 in the thickness direction in the step [3A], the occurrence of breakage in the substrate 4 and thus the adhesive tape 100 can be appropriately suppressed or prevented. Also, even if the laser beam 151 is focused on the top of the thin semiconductor substrate 7, the occurrence of breakage in the substrate 4 and thus the adhesive tape 100 can be appropriately suppressed or prevented.

Such resin materials include, for example, thermoplastic resins such as polyolefin resins, polyester resins (ester polymers) such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate, polyvinyl chloride resins, polyurethane, polyimide, polyamide, polyether ketones such as polyether ether ketone, polyether sulfone, polystyrene, fluororesin, silicone resin, cellulose resin, styrene thermoplastic elastomers (styrene polymers), acrylic resins, polyester thermoplastic elastomers, polyvinyl isoprene, and polycarbonate (carbonate polymers), as well as mixtures of these thermoplastic resins. This makes it relatively easy to keep the weight reduction rate of the substrate 4 to 50% or less.

These resin materials are materials that can transmit energy rays such as light (visible light, near infrared rays, ultraviolet rays), X-rays, and electron beams, and therefore can be preferably used when irradiating the adhesive layer 2 with energy rays from the substrate 4 side, passing through the substrate 4. Therefore, by irradiating the adhesive layer 2 with energy rays from the substrate 4 side, the adhesiveness of the adhesive layer 2 can be reduced, making it easier to pick up the semiconductor chip 20. In addition, the weight reduction rate of the substrate 4 can be set to 50% or less with relative ease.

In particular, it is preferable to use a polyolefin-based resin as the resin material. By using a polyolefin-based resin, it is possible to reliably impart extensibility (expandability) to the base material 4 in the expanding process, and it is also possible to more easily set the weight loss rate of the base material 4 to 50% or less.

Such polyolefin resins are not particularly limited, but examples include polyethylene resins such as linear low-density polyethylene, low-density polyethylene, and very low-density polyethylene; ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-methacrylate copolymer (EMAA); and ethylene copolymers such as ionomers such as ethylene-based ionomers crosslinked with zinc ions, sodium ions, or potassium ions. One or more of these can be used in combination.

Furthermore, it is preferable that the polyolefin resin, particularly the polyethylene resin, mainly contains components with a specific gravity of 0.94 or less, and more preferably contains components with a specific gravity of 0.92 or less. This allows the weight loss rate of the substrate 4 to be reliably set to 50% or less. Note that "mainly" means that the weight fraction of the components that satisfy the above specific gravity range in the polyolefin resin (polyethylene resin) is more than 50%.

Also, the polyolefin resin, particularly the polyethylene resin, may be a mixture (blend) of a low-specific gravity component with a relatively low specific gravity and a high-specific gravity component with a higher specific gravity. This makes it possible to obtain a substrate 4 that can more accurately suppress or prevent breakage in the adhesive tape 100. The weight ratio of the low-specific gravity component is preferably higher than the weight ratio of the high-specific gravity component. Specifically, the weight fraction of the low-specific gravity component in the polyolefin resin (polyethylene resin) is preferably 55% or more and 90% or less, and more preferably 60% or more and 80% or less. This makes it possible to obtain a substrate 4 that can particularly accurately suppress or prevent breakage in the adhesive tape 100.

The specific gravity of the low specific gravity component is preferably within the above range (preferably 0.94 or less, more preferably 0.92 or less). Furthermore, from the viewpoint of effectively improving the properties of the substrate 4, the difference in specific gravity between the low specific gravity component and the high specific gravity component is preferably 0.10 or more, and more preferably 0.15 or more and 0.50 or less.

The base material 4 preferably contains a conductive material that has electrical conductivity. By including such a conductive material, the conductive material can function as an antistatic agent, and can accurately suppress or prevent the generation of static electricity in the semiconductor chips 20 formed by cutting the semiconductor substrate 7 during cutting of the semiconductor substrate 7 in the step [3A].

The conductive material is not particularly limited as long as it is a material that is conductive. Examples of conductive materials include surfactants, permanently antistatic polymers (IDPs), metal materials, metal oxide materials, and carbon-based materials, and one or more of these can be used in combination.

Among these, examples of surfactants include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants.

As permanently antistatic polymers (IDPs), all IDPs can be used, such as polyether and polyolefin block polymers, polyesteramides, polyesteramides, polyetheresteramides, polyurethanes, etc.

Metal materials include gold, silver, copper or silver-coated copper, nickel, etc., and powders of these metals are preferably used.

Examples of metal oxide materials include indium tin oxide (ITO), indium oxide (IO), antimony tin oxide (ATO), indium zinc oxide (IZO), tin oxide (SnO ₂ ), zinc oxide (ZnO), and the like, and powders of these metal oxides are preferably used.

Furthermore, examples of carbon-based materials include carbon black, carbon nanotubes such as single-walled carbon nanotubes and multi-walled carbon nanotubes, carbon nanofibers, CN nanotubes, CN nanofibers, BCN nanotubes, BCN nanofibers, graphene, etc.

Among these, the conductive material is preferably at least one of permanently antistatic polymers (IDPs), metal oxide materials, and carbon black. These have a small humidity dependency of resistivity, so that even if the semiconductor substrate 7 is exposed to a dry environment, the amount of change in the surface resistance value can be reduced.

In addition, the surface resistivity of the upper surface (one surface) of the substrate 4 is preferably set to more than 1.0×10 ⁸ (Ω/□), more preferably more than 1.0×10 ⁸ (Ω/□) and 1.0×10 ¹⁶ (Ω/□) or less, and the volume resistivity is preferably set to 1.0×10 ¹⁶ (Ω·m) or less, more preferably 1.0×10 ¹¹ (Ω·m) or more and 1.0×10 ¹³ (Ω·m) or less. By setting the surface resistivity of the upper surface (one surface) of the substrate 4 and the volume resistivity of the substrate 4 as described above, the conductive material contained in the substrate 4 can suitably exhibit the function as an antistatic agent, and the generation of static electricity in the semiconductor substrate 7 and the semiconductor chip 20 can be more appropriately suppressed or prevented during the dicing of the semiconductor substrate 7 in the step [3A], the expanding of the adhesive tape 100 in the step [5A], and the picking up of the semiconductor chip 20 in the step [6A].

Furthermore, the base material 4 may contain softeners such as mineral oil, fillers such as calcium carbonate, silica, talc, mica, and clay, antioxidants, light stabilizers, lubricants, dispersants, neutralizing agents, colorants, etc.

The thickness of the substrate 4 is, for example, preferably 30 μm or more and 300 μm or less, and more preferably 50 μm or more and 250 μm or less. When the thickness of the substrate 4 is within this range, the substrate 4 can more reliably perform its function, and the expansion (stretching) of the adhesive tape 100 in the step [5A] and the pick-up of the semiconductor chip 20 in the step [6A] can be performed with excellent workability while accurately suppressing or preventing breakage of the substrate 4 during dicing of the semiconductor substrate 7 by irradiation with the laser beam 151 in the step [3A].

Furthermore, the substrate 4 may have exposed on its surface a functional group, such as a carboxyl group, a hydroxyl group, or an amino group, that is reactive with the constituent material contained in the adhesive layer 2.

The substrate 4 may also be made of a laminate (multilayer body) in which multiple layers made of different resin materials are laminated together. Furthermore, the substrate 4 may be made of a blend film in which the resin materials are dry-blended.

As mentioned above, the weight reduction rate of the base material 4 may be 50% or less, but it is preferable that the weight reduction rate is 45% or less, and more preferably 40% or less. This makes it possible to more accurately suppress or prevent breakage of the base material 4 and thus the adhesive tape 100 due to the irradiation of the laser beam 151 to the semiconductor substrate 7 in the step [3A].

On the other hand, the lower limit of the weight loss rate (weight loss rate from room temperature to 420°C) does not have to be set, but taking into consideration the balance with other properties of the substrate 4, it is preferably set to 15% or more, and more preferably 20% or more. This gives the substrate 4 an appropriate degree of flexibility, and makes it possible to more accurately suppress or prevent breakage of the substrate 4 during dicing, expanding, and picking up.

Furthermore, in the substrate 4, the weight loss rate from room temperature (25°C) to 450°C in the TG curve obtained by simultaneous differential thermal and thermogravimetric measurement in accordance with JIS K 0129 is higher than the weight loss rate from room temperature to 420°C described above. Even in this case, the upper limit of the weight loss rate (weight loss rate from room temperature to 450°C) is preferably 95% or less, more preferably 90% or less, and even more preferably 80% or less. This makes it possible to more accurately suppress or prevent breakage in the substrate 4 and thus the adhesive tape 100 due to the irradiation of the semiconductor substrate 7 with the laser beam 151 in the step [3A].

On the other hand, the lower limit of the weight loss rate (weight loss rate from room temperature to 450°C) does not have to be set, but taking into consideration the balance with other properties of the substrate 4, it is preferably set to more than 50%, and more preferably 55% or more. This gives the substrate 4 an appropriate degree of flexibility, and makes it possible to more accurately suppress or prevent breakage of the substrate 4 during dicing, expanding, and picking up.

Furthermore, in the substrate 4, the weight loss rate from room temperature (25°C) to 400°C in the TG curve obtained by simultaneous differential thermal and thermogravimetric measurement in accordance with JIS K 0129 is lower than the weight loss rate from room temperature to 420°C described above. Even in this case, the upper limit of the weight loss rate (weight loss rate from room temperature to 400°C) is preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less. This makes it possible to more accurately suppress or prevent the occurrence of breakage in the substrate 4 and thus the adhesive tape 100 due to the irradiation of the laser beam 151 to the semiconductor substrate 7 in the step [3A]. Also, good heat resistance can be imparted to the substrate 4.

On the other hand, the lower limit of the weight loss rate (weight loss rate from room temperature to 400°C) does not have to be set, but taking into consideration the balance with other properties of the substrate 4, it is preferably set to 3% or more, and more preferably 5% or more. This gives the substrate 4 an appropriate degree of flexibility, and makes it possible to more accurately suppress or prevent breakage of the substrate 4 during dicing, expanding, and picking up.

Furthermore, the tensile modulus of elasticity of the substrate 4 at 23°C is preferably 200 MPa or less, more preferably 40 MPa or more and 150 MPa or less, and even more preferably 50 MPa or more and 130 MPa or less. This allows the expansion (stretching) of the adhesive tape 100 in the step [5A], and furthermore the pick-up of the semiconductor chip 20 in the step [6A], which is carried out after this expansion, to be carried out with excellent workability.

The substrate 4 may also be configured to be irradiated with an electron beam. In this case, the substrate 4 is preferably irradiated with an electron beam under conditions of an absorbed dose of 20 to 300 kGy. In this case, the accelerating voltage of the electron beam irradiation is preferably 100 to 300 kV.

By irradiating the substrate 4 with an electron beam, it is possible to more accurately suppress or prevent breakage in the substrate 4 and, in turn, the adhesive tape 100 caused by irradiation of the semiconductor substrate 7 with the laser beam 151 in the step [3A].

<Adhesive layer 2>
The adhesive layer 2 has a function of adhering and supporting the semiconductor substrate 7 when the semiconductor substrate 7 is diced in the step [3A]. The adhesive layer 2 is configured such that the adhesiveness to the semiconductor chip 20 is reduced by applying energy to the adhesive layer 2 in the step [4A]. This allows the semiconductor chip 20 obtained by dicing the semiconductor substrate 7 to be easily peeled off from the adhesive layer 2. As a result, the adhesive layer 2 can exert an adhesive force sufficient to allow the semiconductor chip 20 to be picked up in the step [6A].

The adhesive layer 2 having such a function is composed of a resin composition containing as its main materials (1) a base resin having adhesive properties and (2) a curable resin that hardens the adhesive layer 2. Below, each component contained in the resin composition will be explained in order.

(1) Base Resin The base resin has adhesiveness and is contained in the resin composition in order to impart adhesiveness to the semiconductor substrate 7, and ultimately to the semiconductor chip 20, to the adhesive layer 2 before the adhesive layer 2 is irradiated with energy rays.

Such base resins include known resins used as adhesive layer components, such as acrylic resins (adhesives), silicone resins (adhesives), polyester resins (adhesives), polyvinyl acetate resins (adhesives), polyvinyl ether resins (adhesives), styrene elastomer resins (adhesives), polyisoprene resins (adhesives), polyisobutylene resins (adhesives), and urethane resins (adhesives). Among these, it is preferable to use acrylic resins. Acrylic resins are preferably used as base resins because they have excellent heat resistance and are relatively easy and inexpensive to obtain.

Acrylic resins are resins whose base polymer is a polymer (homopolymer or copolymer) whose main monomer component is (meth)acrylic acid ester.

The (meth)acrylic acid ester is not particularly limited, but examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, and decyl (meth)acrylate. Examples of the acrylate include alkyl (meth)acrylate esters such as isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, and octadecyl (meth)acrylate, cycloalkyl (meth)acrylate esters such as cyclohexyl (meth)acrylate, and aryl (meth)acrylate esters such as phenyl (meth)acrylate, and these may be used alone or in combination of two or more. Among these, alkyl (meth)acrylate esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and octyl (meth)acrylate are preferred. Alkyl (meth)acrylate esters are particularly excellent in heat resistance and can be obtained relatively easily and inexpensively.

In this specification, the term (meth)acrylic acid ester is used to include both acrylic acid ester and methacrylic acid ester.

　The acrylic resin is configured to contain copolymerizable monomers as monomer components that make up the polymer, if necessary, for the purpose of modifying the cohesive strength, heat resistance, etc.

Such copolymerizable monomers are not particularly limited, but include, for example, hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate, epoxy group-containing monomers such as glycidyl (meth)acrylate, carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride, amide monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane(meth)acrylamide, N-methoxymethyl(meth)acrylamide, and N-butoxymethyl(meth)acrylamide, and amino group-containing monomers such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate. , cyano group-containing monomers such as (meth)acrylonitrile, olefin-based monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene, styrene-based monomers such as styrene, α-methylstyrene, and vinyl toluene, vinyl ester-based monomers such as vinyl acetate and vinyl propionate, vinyl ether-based monomers such as methyl vinyl ether and ethyl vinyl ether, halogen atom-containing monomers such as vinyl chloride and vinylidene chloride, alkoxy group-containing monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, and monomers having a nitrogen atom-containing ring such as N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, and N-(meth)acryloylmorpholine. These can be used alone or in combination of two or more.

The content of these copolymerizable monomers is preferably 40% by weight or less, and more preferably 10% by weight or less, based on the total monomer components constituting the acrylic resin.

The copolymerizable monomer may be contained at the end of the main chain of the polymer constituting the acrylic resin, or may be contained within the main chain, or may be contained both at the end of the main chain and within the main chain.

Furthermore, the copolymerizable monomer may contain a multifunctional monomer for the purpose of crosslinking between polymers, etc.

Examples of polyfunctional monomers include 1,6-hexanediol (meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, glycerin di(meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, urethane (meth)acrylate, divinylbenzene, butyl di(meth)acrylate, hexyl di(meth)acrylate, etc., and one or more of these can be used in combination.

Ethylene-vinyl acetate copolymers and vinyl acetate polymers can also be used as copolymerizable monomer components.

In addition, it is preferable that the glass transition point of this acrylic resin is 20°C or lower. This allows the adhesive layer 2 to exhibit excellent adhesiveness before the adhesive layer 2 is irradiated with energy rays.

Such acrylic resins (polymers) can be produced by polymerizing a single monomer component or a mixture of two or more monomer components. The polymerization of these monomer components can be carried out using a polymerization method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, etc.

The acrylic resin preferably has a functional group (reactive functional group) that is reactive to a crosslinking agent or a photopolymerization initiator, such as a hydroxyl group or a carboxyl group (particularly a hydroxyl group). This allows the crosslinking agent or photopolymerization initiator to be linked to the acrylic resin, which is a polymer component, and therefore it is possible to appropriately suppress or prevent the crosslinking agent or photopolymerization initiator from leaking out of the adhesive layer 2. As a result, the adhesiveness of the adhesive layer 2 to the semiconductor substrate 7, and in turn to the semiconductor chip 20, is reliably reduced by the energy ray irradiation in the step [4A].

(2) Curable Resin The curable resin has a curing property of being cured by, for example, irradiation with energy rays. As a result of this curing, the base resin is incorporated into the cross-linked structure of the curable resin, and as a result, the adhesive strength of the adhesive layer 2 decreases.

As such a curable resin, for example, a low molecular weight compound is used that has at least two polymerizable carbon-carbon double bonds in the molecule as functional groups that can be three-dimensionally crosslinked by irradiation with energy rays such as ultraviolet rays or electron beams.

Specific examples of the curable resin include esters of (meth)acrylic acid and polyhydric alcohols such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and glycerin di(meth)acrylate, ester acrylate oligomers, cyanurate compounds having a carbon-carbon double bond-containing group such as 2-propenyl-di-3-butenyl cyanurate, and tris(2-acryloxyethyl)isocyanurate. Examples of the acrylates include isocyanurate compounds having a carbon-carbon double bond-containing group such as tris(2-methacryloxyethyl)isocyanurate, 2-hydroxyethyl bis(2-acryloxyethyl)isocyanurate, bis(2-acryloxyethyl)2-[(5-acryloxyhexyl)-oxy]ethyl isocyanurate, tris(1,3-diacryloxy-2-propyl-oxycarbonylamino-n-hexyl)isocyanurate, tris(1-acryloxyethyl-3-methacryloxy-2-propyl-oxycarbonylamino-n-hexyl)isocyanurate, and tris(4-acryloxy-n-butyl)isocyanurate; commercially available oligoester acrylates, epoxy acrylates such as bis-F type epoxy acrylate and bis-A type epoxy acrylate; urethane acrylates; polyester acrylates; and aromatic and aliphatic urethane acrylates, and any combination of two or more of these may be used. Among these, it is preferable to contain at least one of epoxy acrylate, urethane acrylate, and polyester acrylate, and urethane acrylate is more preferable.

The urethane acrylate is not particularly limited, but can be obtained, for example, by reacting a polyol compound such as a polyester type or polyether type with a polyisocyanate compound (e.g., 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane 4,4-diisocyanate, etc.) to obtain an isocyanate-terminated urethane prepolymer, which is then reacted with a (meth)acrylate having a hydroxyl group (e.g., 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, polyethylene glycol (meth)acrylate, etc.).

An example of a polyester acrylate is polyester (meth)acrylate.

The curable resin may be a mixture of two or more curable resins with different weight average molecular weights, although this is not particularly limited. By using such a curable resin, the degree of crosslinking of the resin by energy ray irradiation can be easily controlled, and the semiconductor chip 20 can be easily picked up from the adhesive layer 2. As such a curable resin, for example, a mixture of a first curable resin and a second curable resin having a weight average molecular weight larger than that of the first curable resin may be used.

The curable resin is preferably mixed in an amount of 5 parts by weight to 100 parts by weight, more preferably 10 parts by weight to 100 parts by weight, and even more preferably 20 parts by weight to 100 parts by weight. By adjusting the amount of the curable resin mixed as described above, the semiconductor chip 20 can be easily picked up from the adhesive layer 2.

In addition, when a double bond-introduced acrylic resin is used as the base resin described above, that is, when an acrylic resin having a carbon-carbon double bond in a side chain, in the main chain, or at the end of the main chain is used, the addition of this curable resin to the resin composition may be omitted. This is because when the acrylic resin is a double bond-introduced acrylic resin, the adhesive layer 2 is cured by irradiation with energy rays due to the function of the carbon-carbon double bond contained in the double bond-introduced acrylic resin, and as a result, the adhesive strength of the adhesive layer 2 is reduced.

(3) Photopolymerization Initiator The adhesive layer 2 is configured so that its adhesiveness to the semiconductor substrate 7 and ultimately to the semiconductor chip 20 decreases when irradiated with energy rays. When ultraviolet rays or the like are used as the energy rays, it is preferable that the curable resin contains a photopolymerization initiator to facilitate the initiation of polymerization of the curable resin.

Examples of photopolymerization initiators include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, 4-(2-hydroxyethoxy)phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, 1-hydroxycyclohexyl phenyl ketone, Michler's ketone, ton, acetophenone, methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropan-1-one, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl, benzoin, dibenzyl, α-hydroxycyclohexyl phenyl ketone, benzil dimethyl ketal, 2-hydroxymethylphenylpropane, 2-naphthalenesulfonyl chloride, 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime, benzophenone , benzoylbenzoic acid, 4,4'-dimethylaminobenzophenone, 4,4'-diethylaminobenzophenone, 4,4'-dichlorobenzophenone, 3,3'-dimethyl-4-methoxybenzophenone, o-acryloxybenzophenone, p-acryloxybenzophenone, o-methacryloxybenzophenone, p-methacryloxybenzophenone, p-(meth)acryloxyethoxybenzophenone, benzophenone-4-carboxylic acid esters of acrylates such as 1,4-butanediol mono(meth)acrylate, 1,2-ethanediol mono(meth)acrylate, 1,8-octanediol mono(meth)acrylate, thioxanthone, 2-chlorothioxanthone, Examples include 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, azobisisobutyronitrile, β-chloroanthraquinone, camphorquinone, halogenated ketone, acylphosphinoxide, acylphosphonate, polyvinylbenzophenone, chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, 2-ethylanthraquinone, t-butylanthraquinone, 2,4,5-triaryl-imidazole dimer, and the like. One or more of these can be used in combination.

Among these, benzophenone derivatives and alkylphenone derivatives are preferred. These compounds have a hydroxyl group as a reactive functional group in the molecule, and can be linked to a base resin or a curable resin via this reactive functional group, allowing them to more reliably function as a photopolymerization initiator.

The photopolymerization initiator is preferably mixed in an amount of 0.1 parts by weight or more and 50 parts by weight or less, and more preferably 0.5 parts by weight or more and 10 parts by weight or less, per 100 parts by weight of the base resin. By adjusting the amount of the photopolymerization initiator mixed as described above, the pickup properties of the semiconductor chip 20 are optimized.

(4) Crosslinking Agent The curable resin may further contain a crosslinking agent, which improves the curability of the curable resin.

The crosslinking agent is not particularly limited, but examples thereof include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, urea resin-based crosslinking agents, methylol-based crosslinking agents, chelate-based crosslinking agents, aziridine-based crosslinking agents, melamine-based crosslinking agents, polyvalent metal chelate-based crosslinking agents, acid anhydride-based crosslinking agents, polyamine-based crosslinking agents, and carboxyl group-containing polymer-based crosslinking agents. Of these, isocyanate-based crosslinking agents are preferred.

Isocyanate-based crosslinking agents are not particularly limited, but examples include polyisocyanate compounds of polyisocyanates, trimers of polyisocyanate compounds, trimers of terminal isocyanate compounds obtained by reacting a polyisocyanate compound with a polyol compound, and blocked polyisocyanate compounds in which terminal isocyanate urethane prepolymers are blocked with phenols, oximes, etc.

Furthermore, examples of polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, 4,4'-diphenylether diisocyanate, 4,4'-[2,2-bis(4-phenoxyphenyl)propane]diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, and the like, and one or more of these can be used in combination. Among these, at least one polyisocyanate selected from the group consisting of 2,4-tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, and hexamethylene diisocyanate is preferred.

The crosslinking agent is preferably mixed in an amount of 0.01 parts by weight or more and 50 parts by weight or less, and more preferably 5 parts by weight or more and 50 parts by weight or less, per 100 parts by weight of the base resin. By adjusting the amount of crosslinking agent mixed as described above, the pick-up properties of the semiconductor chip 20 from the adhesive layer 2 can be optimized.

(5) Plasticizer Furthermore, a plasticizer may be contained in the resin composition constituting the adhesive layer 2. By containing a plasticizer, it is possible to improve the flexibility of the adhesive layer 2, the adhesive strength of which decreases due to the application of energy.

The plasticizer is not particularly limited, but examples thereof include phthalate ester plasticizers such as DOP (dioctyl phthalate), DBP (dibutyl phthalate), DIBP (diisobutyl phthalate), and DHP (diheptyl phthalate), aliphatic dibasic acid ester plasticizers such as DOA (di-2-ethylhexyl adipate), DIDA (diisodecyl adipate), and DOS (di-2-ethylhexyl sebacate), aromatic carboxylic acid ester plasticizers such as ethylene glycol benzoates, and trimellitic acid ester plasticizers such as TOTM (trioctyl trimellitate), adipate ester plasticizers, and polyester plasticizers, and one or more of these may be used in combination. Among these, polyester plasticizers are preferred. By using a polyester plasticizer as the plasticizer, the effect obtained by including a plasticizer in the resin composition constituting the adhesive layer 2 can be more significantly exhibited.

Polyester plasticizers are obtained, for example, by the condensation polymerization reaction of polycarboxylic acids such as adipic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, and terephthalic acid with glycols such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, and hexanediol.

The content of the plasticizer in the adhesive layer 2, i.e., the resin composition, is not particularly limited, but is preferably, for example, 8% by weight to 60% by weight, more preferably 10% by weight to 58% by weight, and even more preferably 15% by weight to 55% by weight. This reliably improves the flexibility of the adhesive layer 2, and the effect of the adhesive layer 2 containing a plasticizer can be more significantly exhibited.

(6) Conductive materials (antistatic agents)
Furthermore, it is preferable that the resin composition constituting the adhesive layer 2 contains a conductive material having electrical conductivity. By containing such a conductive material, the conductive material can function as an antistatic agent, and the generation of static electricity in the semiconductor chip 20 in the above-mentioned manufacturing method of the semiconductor chip 20 can be appropriately suppressed or prevented.

This conductive material is not particularly limited as long as it has conductivity. As with the conductive material that may be contained in the substrate 4, examples of this conductive material include surfactants, permanently antistatic polymers (IDPs), metal materials, metal oxide materials, and carbon-based materials, and one or more of these may be used in combination.

When a conductive material is contained in either the base material 4 or the adhesive layer 2, it is preferable that the conductive material is contained in the base material 4. This makes it possible to more accurately suppress or prevent the generation of static electricity in the semiconductor chip 20 without having to reliably attach the conductive material to the semiconductor chip 20.

(7) Other Components The resin composition constituting the adhesive layer 2 may further contain, in addition to the above-mentioned components (1) to (6), at least one of other components selected from the group consisting of a tackifier, an antiaging agent, an adhesion adjuster, a filler, a colorant, a flame retardant, a softener, an antioxidant, and a surfactant as a leveling agent.

The tackifiers among these are not particularly limited, but examples include rosin resins, terpene resins, coumarone resins, phenolic resins, aliphatic petroleum resins, aromatic petroleum resins, and aliphatic-aromatic copolymer petroleum resins, and one or more of these can be used in combination.

The average thickness of the adhesive layer 2 is not particularly limited, but is preferably, for example, 5 μm to 30 μm, more preferably 7 μm to 25 μm, and even more preferably 10 μm to 20 μm. By setting the average thickness of the adhesive layer 2 within this range, the adhesive layer 2 exhibits good adhesive strength before energy is applied to the adhesive layer 2, and exhibits good peelability between the adhesive layer 2 and the semiconductor chip 20 after energy is applied to the adhesive layer 2.

The adhesive layer 2 may be composed of a laminate (multilayer body) in which multiple layers composed of different resin compositions are laminated together.

In addition, the adhesive tape 100 having such a configuration can be manufactured by, for example, applying or spraying a liquid material, which is a varnish-like material made by dissolving the resin composition that constitutes the adhesive layer 2 in a solvent, onto a separator, and then volatilizing the solvent to form the adhesive layer 2, and then pressing the substrate 4 onto the surface of this adhesive layer 2 opposite the separator, so that the adhesive layer 2 is formed on the separator.

The adhesive tape 100 manufactured as described above is used after peeling the adhesive tape 100 from the separator in the method for manufacturing a semiconductor device using the adhesive tape 100 described above.

The adhesive tape of the present invention has been described above, but the present invention is not limited to these.

For example, any component capable of exerting the same function may be added to each layer of the adhesive tape of the present invention, or the substrate may be composed of one layer as described in the above embodiment, or may be composed of multiple layers, and for example, an antistatic layer may be provided on the surface of the substrate opposite the adhesive layer.

In addition, the configuration of each layer of the adhesive tape can be replaced with any configuration that can exert a similar function, or any configuration can be added.

Furthermore, the adhesive tape can be used when semiconductor chips (semiconductor elements) are obtained as individual components by irradiating a semiconductor substrate as a substrate with a laser beam, but it can also be used in the same way when cutting (individing) various substrates such as glass substrates, ceramic substrates, resin material substrates, and metal material substrates in the thickness direction by irradiating them with a laser beam.

Furthermore, depending on the configuration of the semiconductor device formed using adhesive tape, it may be possible to omit the formation of the molded portion 17 of the semiconductor device 10.

The semiconductor chip 20 manufactured using the adhesive tape of the present invention can be widely used in, for example, mobile phones, digital cameras, video cameras, car navigation systems, personal computers, game consoles, liquid crystal televisions, liquid crystal displays, organic electroluminescence displays, printers, etc.

Next, specific examples of the present invention will be described.
However, the present invention is not limited to the descriptions in these examples.

1. Preparation of Raw Materials First, the raw materials used in the production of the pressure-sensitive adhesive tapes of the Examples and Comparative Examples are shown below.

(Polyolefin Resin 1)
As polyolefin resin 1, a mixture containing linear low density polyethylene (LLDPE) and low density polyethylene (LDPE) in a weight ratio (LLDPE:LDPE) of 7:3 was prepared.

(Polyolefin Resin 2)
As the polyolefin resin 2, a mixture containing linear low density polyethylene (LLDPE) and low density polyethylene (LDPE) in a weight ratio (LLDPE:LDPE) of 6:4 was prepared.

(Polyolefin Resin 3)
As the polyolefin resin 3, a mixture containing linear low density polyethylene (LLDPE) and low density polyethylene (LDPE) in a weight ratio (LLDPE:LDPE) of 8:2 was prepared.

(Polyolefin Resin 4)
As the polyolefin resin 4, an ethylene-methacrylic acid copolymer (EMAA) having an acid content of 9% was prepared.

(Polyolefin Resin 5)
As the polyolefin resin 5, an ethylene-vinyl acetate copolymer (EVA) having a vinyl acetate content of 16% was prepared.

(Polyolefin Resin 6)
As the polyolefin resin 6, a mixture containing polypropylene (PP) and a styrene-isoprene-styrene block copolymer (SIS) in a weight ratio (PP:SIS) of 6:4 was prepared.

(Antistatic Agent)
As the antistatic agent, a polyether-based antistatic agent ("Pelectron PVL" manufactured by Sanyo Chemical Industries, Ltd.) was prepared.

(Base resin)
As the base resin 1, an acrylic copolymer was prepared by mixing four types of resin, acrylic acid, 2-hydroxyethyl acrylate, 2-ethylhexyl acrylate, and butyl methacrylate, and subjecting the mixture to solution polymerization in a toluene solvent by a conventional method.

The glass transition point and weight average molecular weight of base resin 1 (acrylic copolymer) were -37°C and 600,000, respectively.

(curable resin)
As the curable resin, urethane acrylate (manufactured by Miwon Specialty Chemical Co., Ltd., product number: SC2152) was prepared.

(Crosslinking Agent)
As a crosslinking agent, polyisocyanate (manufactured by Tosoh Corporation, product number: Coronate L) was prepared.

(Photopolymerization initiator)
As a photopolymerization initiator, benzyl dimethyl ketal (manufactured by Tokyo Chemical Industry Co., Ltd.) was prepared.

2. Preparation of adhesive tape [Example 1]
The polyolefin resin 1 (100 parts by weight) was extruded as a resin composition by an extruder to prepare a substrate 4 having a thickness of 150 μm.

Next, a liquid material containing a resin composition containing a base resin (100 parts by weight), a curable resin (40 parts by weight), a crosslinking agent (2 parts by weight), and a photopolymerization initiator (5 parts by weight) was prepared. This liquid material was bar-coated onto a PET separator so that the thickness of the adhesive layer 2 after drying would be 10 μm, and then dried at 80°C for 1 minute to form an adhesive layer 2 on the top surface (one side) of the separator.

Next, the substrate 4 prepared above was attached to the top surface of the adhesive layer 2 to obtain the adhesive tape 100 of Example 1 covered with a separator.

[Examples 2 to 8, Comparative Examples 1 to 2]
Except for changing the type and content of each constituent material in the resin composition as shown in Table 1, the pressure-sensitive adhesive tapes of Examples 2 to 8 and Comparative Examples 1 and 2 were obtained in the same manner as in Example 1.

3. Evaluation <Measurement of weight loss rate in TG curve of substrate>
For the substrate 4 included in the pressure-sensitive adhesive tape 100 of each of the Examples and Comparative Examples, simultaneous differential thermal and thermogravimetric measurements were performed using the apparatus and conditions described below in accordance with a method conforming to JIS K 0129 to obtain a TG curve for the substrate 4. Then, using the obtained TG curve, the weight loss rate from room temperature (25° C.) to 400° C., the weight loss rate from room temperature (25° C.) to 420° C., and the weight loss rate from room temperature (25° C.) to 450° C. were each determined.
Measurement device: STA200 (Hitachi High-Tech Science Corporation)
Atmospheric gas: nitrogen Gas introduction amount: 200 ml/min Temperature increase rate: 5° C./min

<Measurement of tensile modulus of substrate>
The tensile modulus of the substrate 4 of each of the pressure-sensitive adhesive tapes 100 of the Examples and Comparative Examples was measured using a universal tensile tester (manufactured by A&D Co., Ltd., "RTH-1225") The measurement was performed in accordance with JIS K 7161:2014 at a tension speed of 2 mm/min in an environment of 23°C.

<Evaluation of the presence or absence of breakage in adhesive tape>
For each of the adhesive tapes 100 in each of the examples and comparative examples, the adhesive tape 100 was peeled off from the separator, with the adhesive layer 2 facing up, and a pulsed laser beam was irradiated five times with a focus set on a 50 μm portion of the upper part, i.e., a portion 50 μm above the surface of the adhesive layer 2 in the thickness direction of the adhesive tape 100.

The conditions for irradiating the pulsed laser beam onto the top 50 μm portion of the adhesive tape 100 were as follows:

(Pulse laser beam irradiation conditions)
Light source: Q-switched Nd:YVO4 pulse laser Wavelength: 355 nm pulse laser Repetition rate: 500 kHz
Laser Intensity:
The strength of the pulsed laser beam to cut a 50 μm deep cut into a 125 μm thick PET film (A4130: manufactured by Toyobo Co., Ltd.) with one shot.

Then, after irradiation with the pulsed laser beam, the adhesive tapes of each Example and Comparative Example were visually inspected for the presence or absence of breakage in the adhesive tape (substrate) and were evaluated according to the following criteria.

(Evaluation Criteria)
In adhesive tapes (substrates),
A: 50% or more of the thickness of the substrate remains. B: No obvious breakage is observed. D: Obvious breakage is observed, which significantly affects the function of the adhesive tape.

<Evaluation of silicon chip pick-up ability>
First, a silicon wafer (manufactured by SUMCO) made of silicon was prepared and ground in a conventional manner to obtain a silicon wafer having a thickness of 130 μm, and then the silicon wafer was ground to a thickness of 100 μm with a #2000 wheel, and the adhesive tape 100 of each of the examples and comparative examples was fixed to the ground surface with the adhesive layer 2 facing the silicon wafer side. Then, the silicon wafer was cut in the thickness direction by irradiation with a pulsed laser beam to obtain individual pieces, thereby obtaining a plurality of silicon chips each having a size of 6 mm long x 6 mm wide.

The conditions for irradiating the silicon wafer with the pulsed laser beam were as follows:

(Pulse laser beam irradiation conditions)
Light source: Q-switched Nd:YVO4 pulse laser Wavelength: 355 nm pulse laser Repetition rate: 500 kHz

Thereafter, the adhesive layer 2 was irradiated with ultraviolet light under conditions of ultraviolet illuminance: 55 W/cm ² and ultraviolet irradiation amount: 200 mJ/cm ² to impart energy thereto, thereby curing the adhesive layer 2 .

Then, while the adhesive tape 100 was being expanded radially along its surface, the silicon chip was pushed up using a needle with a tip diameter of 100 μm, with the needle pushing up by a distance of 400 μm.

Next, while the needle was still pushing up the silicon chip, the silicon chip was picked up by suction with the vacuum collet.

By going through the above process, the pick-up of silicon chips by suction was repeated 50 times for each adhesive tape of each example and comparative example.

Then, for the adhesive tapes of each Example and Comparative Example, the success or failure of picking up the silicon chip by adsorption (pickup ability) was evaluated for each obtained silicon chip according to the following criteria.

(Evaluation Criteria)
A: 50 silicon chips could be picked up. B: 48 or more but less than 50 silicon chips could be picked up. C: 40 or more but less than 48 silicon chips could be picked up. D: Less than 40 silicon chips could be picked up. The evaluation results obtained as described above are shown in Table 1.

As shown in Table 1, in each example, by satisfying the requirement that the weight loss rate in the TG curve of the substrate be 50% or less from room temperature to 420°C, the occurrence of breakage in the adhesive tape (substrate) was suppressed, and the silicon chip could be picked up with excellent accuracy.

In contrast, in each of the comparative examples, the weight loss rate in the TG curve of the substrate from room temperature to 420°C did not meet the requirement of 50% or less. As a result, breaks occurred in the adhesive tape (substrate), and as a result, the silicon chip could not be picked up with excellent precision.

According to the present invention, a substrate such as a semiconductor wafer attached to an adhesive tape is cut in the thickness direction by irradiation with a laser beam to separate it into individual pieces. After a dicing process in which components such as semiconductor chips are formed on the adhesive tape, an expanding process in which the adhesive tape is stretched and a pick-up process in which the components are picked up are sequentially performed. This makes it possible to precisely suppress or prevent breakage of the adhesive tape when the substrate is separated into individual pieces in the adhesive tape used to detach components from the adhesive tape. Therefore, the pick-up of components in the pick-up process can be performed with excellent precision. Thus, the present invention has industrial applicability.

Reference Signs List 2 Adhesive layer 4 Base material 7 Semiconductor substrate 9 Wafer ring 10 Semiconductor device 17 Molded portion 20 Semiconductor chip 21 Terminal 23 Semiconductor chip body 25 Gap 30 Interposer 41 Terminal 70 Bump 80 Sealing layer 81 Connection portion 85 Solder bump 100 Adhesive tape 121 Outer periphery 122 Center portion 150 Light beam irradiator 151 Laser beam 200 Pickup table 210 Center portion 220 Outer periphery 250 Dicer table

Claims (10)

An adhesive tape comprising a base material and an adhesive layer containing an adhesive base resin as a main material and laminated on one side of the base material, the adhesive layer being used for cutting the substrate in its thickness direction and dividing the substrate into individual components by irradiating the substrate with a laser beam while the substrate is fixed on the adhesive layer, and then for detaching each of the components from the adhesive layer,
The adhesive tape is characterized in that the substrate has a weight loss rate of 50% or less from room temperature to 420° C. in a TG curve obtained by simultaneous differential thermal and thermogravimetric measurement in accordance with JIS K 0129. The adhesive tape according to claim 1, wherein the tensile modulus of the substrate at 23°C is 200 MPa or less. The adhesive tape according to claim 1, wherein the substrate contains a polyolefin resin as a main material. The adhesive tape according to claim 3, wherein the polyolefin resin is a polyethylene resin. The adhesive tape according to claim 4, wherein the polyethylene resin mainly contains a component whose specific gravity is 0.94 or less. The adhesive tape according to claim 1, wherein the base resin is an acrylic resin. The adhesive tape according to claim 6, wherein the adhesive layer further contains a curable resin that is cured by the application of energy, and is configured such that the adhesive strength of the adhesive layer to the substrate and the component is reduced by the application of energy. The adhesive tape according to claim 1, wherein the substrate has a thickness of 30 μm or more and 300 μm or less. The adhesive tape according to claim 1, wherein the adhesive layer has a thickness of 5 μm or more and 30 μm or less. The adhesive tape according to claim 1, wherein the removal of the component from the adhesive layer is achieved by stretching the adhesive tape in the planar direction, pushing the component up from the substrate side, and then pulling it out from the opposite side of the substrate.