TWI727110B - Adhesive sheet for invisible cutting - Google Patents

Abstract

The present invention provides an adhesive sheet for invisible cutting, which is an adhesive sheet for invisible cutting provided with a substrate and an adhesive layer laminated on one side of the substrate. The substrate is used with a thermomechanical analysis device. The substrate is heated from 25°C to 120°C at a heating rate of 20°C/min, and the substrate is stretched with a load of 0.2g, and the length of the substrate at 60°C is subtracted from the initial length of the substrate. When the change in length of the material is set to △L _60℃ , and the length of the substrate obtained by subtracting the initial length of the substrate at 90℃ is set to △L _90℃ , it conforms to the following The relationship of formula (1): △L _90℃ -△L _60℃ <0μm...(1).

The adhesive sheet for stealth dicing has excellent heat shrinkability.

Description

Adhesive sheet for invisible cutting

The present invention relates to an adhesive sheet for invisible dicing (registered trademark), and preferably relates to an adhesive sheet for invisible dicing using a semiconductor wafer having a through electrode as an object to be processed.

In response to the increase in capacity and functionality of electronic circuits, the development of a multilayer circuit obtained by three-dimensionally layering a plurality of semiconductor chips is in progress. In such a multilayer circuit, wire bonding is generally used to conduct conductive connection of semiconductor wafers in the past. However, due to the necessity of miniaturization and high functionality in recent years, it has been developed not to perform wire bonding but to The semiconductor wafer is provided with electrodes (TSV) penetrating from the circuit formation surface to the back surface, and a method of electrically connecting the wafers located directly above and directly below is an effective technique. As a method of manufacturing a wafer with through-electrodes, for example, a through hole is provided at a predetermined position of a semiconductor wafer using plasma or the like, and a conductor such as copper is poured into the through hole, and then etching is applied to the semiconductor wafer. The method of setting the circuit and the through electrode on the surface of the circle, etc. At this time, the wafer will be heated.

Such ultra-thin wafers and TSV wafers are extremely easy to break, so they may be damaged in the back grinding step, subsequent processing steps, and transportation steps. Therefore, in these steps, the wafer is held on a hard support such as glass via an adhesive.

After the back grinding and processing of the wafer are completed, the wafer is transferred from the hard support to the dicing plate, and the periphery of the dicing plate is fixed with a ring frame, and then the wafer is diced and divided into multiple chips. The wafer is then picked up from the cutting board.

When picking up the wafer obtained by the above-mentioned dicing, a step of expanding (expand) the dicing plate to which the wafer is attached is performed. Thereby, the wafers are separated from each other, and it is easy to pick up the wafers separately. Such expansion is achieved by supporting the pedestal in the area where the chip is attached to the dicing board from the surface opposite to the surface where the chip is attached, so that the height of the ring frame attached to the periphery of the dicing board Relative to the height of the pedestal is lower.

In addition, when performing the expansion described above, it may be implemented to maintain the expanded state to suck the dicing plate by the suction table, and then heat the area between the area where the ring frame is attached and the area where the wafer is attached in the dicing plate. And make it shrink (heat shrink). This shrinkage generates a force extending in the peripheral direction of the area where the wafer is attached to the dicing board. As a result, even after the dicing board is released from the suction by the suction table, the wafers can be kept separated from each other.

One of the problems of Patent Document 1 is to exhibit sufficient shrinkage in the heat shrinking step, and no defects caused by slack after the heat shrinking step. It discloses a wafer processing tape that has a predetermined base film and uses The maximum thermal shrinkage stress caused by the predetermined test is the predetermined value.

[Prior Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent No. 5554118

However, among the dicing methods, there are a dicing method using a dicing blade, a dicing method (invisible dicing) in which a modified part is formed inside the wafer by irradiation of laser light and the modified part is divided into the modified part. Among them, in the method of using a dicing blade, since the part of the wafer that the dicing blade touches is cut, the obtained wafers are separated by the width component of the cut even if they are not expanded. On the other hand, in stealth dicing, a modified part is formed in the wafer by irradiation of laser light, and the wafer is divided into a plurality of wafers in the modified part. Therefore, the portion that is cut as described above does not appear in the wafer, and most of the obtained wafers are in contact with each other without expanding.

Compared with cutting with a dicing knife, it is more difficult to maintain a state where the wafers are separated by a large distance during the aforementioned heat shrinkage when performing stealth cutting, and problems such as picking failures are likely to occur. Therefore, for the adhesive sheets that are also used for invisible dicing, it is particularly required that the adhesive sheets can shrink well due to heat shrinkage and maintain a state in which the wafers are well separated from each other (hereinafter sometimes referred to as "good heat shrinkability" ).

However, conventional adhesive sheets such as the wafer processing tape disclosed in Patent Document 1 have insufficient heat shrinkability. Especially when stealth dicing is performed, it is difficult for the wafers to maintain a sufficiently large distance apart from each other, resulting in easy pickup. Bad problem.

In view of the actual situation, the present invention aims to provide an adhesive sheet for stealth dicing with excellent heat shrinkability.

In order to achieve the above object, the present invention provides an adhesive sheet for stealth dicing (Invention 1), which is an adhesive sheet for stealth dicing provided with a base material and an adhesive layer laminated on one side of the base material. This is: while the substrate is heated from 25°C to 120°C at a heating rate of 20°C/min using a thermomechanical analysis device, the substrate is stretched with a load of 0.2g, and the length of the substrate is at 60°C. The amount of change in the length of the substrate obtained by subtracting the initial length of the substrate is set as △L _60℃ , and the length of the substrate obtained by subtracting the initial length of the substrate from the length of the substrate at 90°C When the length change is set to △L _90℃ , it accords with the relationship of the following formula (1): △L _90℃ -△L _60℃ <0μm...(1).

The above-mentioned invention (Invention 1) of the adhesive sheet for stealth dicing, by using a thermomechanical analysis device to measure the length change of the substrate △L _{90 ℃} and △L _{60 ℃ in} accordance with the relationship of the above formula (1), can perform well Due to its thermal shrinkage, the wafers can be kept separated from each other well, and as a result, the problem of picking failure can be suppressed.

In the above invention (Invention 1), it is preferable that the substrate is heated from 0°C to 200°C at a heating rate of 10°C/min using a differential scanning calorimeter, and the DSC curve for the substrate is at 30°C. The minimum value of the measured value in the range of 100°C is set to H _30°C-100°C , and the measured value at _25°C is set to H. At 25°C, it conforms to the relationship of the following formula (2) (Invention 2) H _{30 ℃-100℃} /H _25℃ ≦4.0...(2).

In the above inventions (Inventions 1 and 2), it is preferable that the substrate is heated from 0°C to 200°C at a temperature increase rate of 10°C/min using a differential scanning calorimeter in the DSC curve for the substrate. The minimum value of the measured value in the range of 105°C to 200°C is set to H _{105°C-200°C} , and the measured value at _25°C is set to H 25°C, which conforms to the relationship of the following formula (3) (Invention 3 )H _{105℃-200℃} /H _25℃ ≧1.0...(3).

In the above inventions (Inventions 1 to 3), it is preferable that the substrate is heated from 0°C to 200°C at a heating rate of 10°C/min using a differential scanning calorimeter in the DSC curve for the substrate. The minimum value of the measured value in the range of 30℃ to 100℃ is set to H _30℃-100℃ , and the minimum value of the measured value in the range of 105℃ to 200℃ is set to H _{105℃-200℃} When it meets the relationship of the following formula (4) (Invention 4) H _{105°C-200°C} /H _30°C-100°C ≧0.1...(4).

In the above inventions (Inventions 1 to 4), the tensile elastic modulus of the substrate at 23°C is preferably 50 MPa or more and 450 MPa or less (Invention 5).

In the above inventions (Inventions 1 to 5), it is preferable to use a semiconductor wafer having a through electrode as the object to be processed (Invention 6).

In the above inventions (Inventions 1 to 6), it is preferable to use a semiconductor device having a step of shrinking by heating in the region where the object is not laminated in the adhesive sheet for invisible dicing on which the object is laminated Manufacturing method (Invention 7).

The adhesive sheet for invisible cutting of the present invention has excellent heat shrinkability.

The following describes the embodiments of the present invention.

The adhesive sheet for invisible dicing of the present invention includes a base material and an adhesive layer laminated on one side of the base material.

1. Constituents of the adhesive sheet for invisible cutting

(1) Substrate

In the adhesive sheet for stealth dicing of this embodiment, the substrate is heated from 25°C to 120°C at a heating rate of 20°C/min using a thermomechanical analysis device, and the substrate is stretched with a load of 0.2g. , The length of the substrate obtained by subtracting the initial length of the substrate from the length of the substrate at 60°C is set to ΔL _60°C (μm), and the length of the substrate at 90°C is subtracted When the length change of the substrate obtained from the initial length of the substrate is set to △L _90℃ (μm), the substrate conforms to the relationship of the following formula (1): △L _90℃ -△L _60℃ <0μm. ..(1).

When the substrate meets the relationship of the above formula (1), it means that the length of the substrate at 90°C is shorter than the length at 60°C. Therefore, when the substrate is heated to a temperature of, for example, 90°C or higher and 200°C or lower when thermally shrinking, the substrate can shrink well. As a result, the adhesive sheet for invisible dicing provided with the substrate has excellent heat shrinkability. After heat shrinking, the wafers can be well maintained in a separated state, and the collision between the wafers can be suppressed. Pick up. In addition, the details of the aforementioned change amounts ΔL _90°C and ΔL _{60°C are} as described in the test example described later.

In addition, considering the viewpoint that the adhesive sheet for stealth dicing exhibits better heat shrinkability, the value of ΔL _90°C -ΔL _60°C is particularly preferably -10 μm or less. In addition, _{the lower limit of the value of ΔL 90°C} -ΔL _60°C is not particularly limited, but it is usually -3000 μm or more, particularly preferably -2000 μm or more.

In addition, the object to be processed using the adhesive sheet for stealth dicing of this embodiment is, for example, semiconductor components such as semiconductor wafers and semiconductor packages, and glass components such as glass plates. The above-mentioned semiconductor wafer may also be a semiconductor wafer (TSV wafer) having through-electrodes. The adhesive sheet for invisible dicing of this embodiment, as described above, can suppress the collision of the wafers after heat shrinkage. Therefore, it can be effective even when using thin processing objects that are prone to chip damage due to the collision. Suppress this damage. Therefore, as an object to be processed using an adhesive sheet for stealth dicing, in general, a semiconductor wafer having a through electrode having a very thin thickness is suitable.

The adhesive sheet for stealth dicing of this embodiment is preferably heated from 0°C to 200°C at a temperature increase rate of 10°C/min using a differential scanning calorimeter. The DSC curve for the substrate will be at 30°C. The minimum value of the measured value (mW) in the range of 100℃ is set to H _30℃-100℃ , and the measured value (mW) at _25℃ is set to H 25℃, the substrate conforms to the following formula (2) The relationship is H _30℃-100℃ /H _25℃ ≦4.0...(2).

When the base material conforms to the above formula (2), the tendency of the base material not to have an endothermic peak in the temperature range of 30°C to 100°C increases, and the melting point of the base material is higher. Therefore, the substrate and the adhesive sheet for invisible dicing provided with the substrate have excellent heat resistance. In particular, even when the adhesive sheet for invisible cutting is placed on a heated suction table, it is still possible to suppress adhesion to the suction table due to the softening of the base material, and it is possible to separate the adhesive sheet for invisible cutting from the suction table well. . In addition, the details of the measurement method using the above-mentioned differential scanning calorimeter are as described in the test example described later.

Considering that the adhesive sheet for stealth dicing exhibits better heat resistance, the value of H _30°C-100°C /H _25°C is particularly preferably 3.0 or less. In addition, the lower _{limit of the value of H 30°C-100°C} /H _25°C is not particularly limited, but it is usually preferably 0.1 or more.

The adhesive sheet for stealth dicing of this embodiment is preferably heated from 0°C to 200°C at a heating rate of 10°C/min using a differential scanning calorimeter. The DSC curve for the substrate will be at 105°C. The minimum value of the measured value (mW) in the range of 200℃ is set to H _{105℃-200℃} , and the measured value (mW) at _25℃ is set to H 25℃, the substrate conforms to the following formula (3) The relationship: H _{105℃-200℃} /H _25℃ ≧1.0...(3).

When the base material conforms to the above formula (3), the base material easily conforms to the relationship of the above formula (1), and the adhesive sheet for invisible dicing provided with the base material can effectively exhibit excellent heat shrinkability. As a result, after heat shrinking, the state of the wafers separated from each other can be maintained more satisfactorily, and good picking up with suppressed collision of the wafers can be effectively performed. In addition, the details of the measurement method using the differential scanning calorimeter described above are as described in the test example described later.

In addition, considering that the adhesive sheet for stealth dicing exhibits better heat resistance, the value of H _{105°C-200°C} /H _25°C is particularly preferably 1.1 or more. In addition, the _{upper limit of the value of H 105°C-200°C} /H _25°C is not particularly limited, but it is generally preferably 20 or less.

The adhesive sheet for stealth dicing of this embodiment is preferably heated from 0°C to 200°C at a temperature increase rate of 10°C/min using a differential scanning calorimeter. The DSC curve for the substrate will be at 30°C. The minimum value of the measured value (mW) in the range of 100℃ is set to H _30℃-100℃ , and the minimum value of the measured value (mW) at 105℃ to 200℃ is set to H _{105℃-200℃} When it is in accordance with the relationship of the following formula (4): H _{105℃-200℃} /H _30℃-100℃ ≧0.1...(4).

When the base material conforms to the above formula (4), the base material easily conforms to the relationship of the above formula (1), and the adhesive sheet for invisible dicing provided with the base material can effectively exhibit excellent heat shrinkability. As a result, after heat shrinking, the state of the wafers separated from each other can be maintained more satisfactorily, and good picking up with suppressed collision of the wafers can be effectively performed. In addition, when the substrate meets the above formula (4), the substrate has an increased tendency to have no endothermic peak in the temperature range of 30°C to 100°C, and the tendency to have an endothermic peak in the temperature range of 105°C to 200°C increases. The melting point of the substrate is higher than high. As a result, the substrate and the adhesive sheet for stealth dicing provided with the substrate have excellent heat resistance. In particular, even when the adhesive sheet for invisible cutting is placed on a heated suction table, it is still possible to suppress adhesion to the suction table due to the softening of the base material, and it is possible to separate the adhesive sheet for invisible cutting from the suction table well. . In addition, the details of the measurement method using the differential scanning calorimeter described above are as described in the test example described later.

Considering that the adhesive sheet for stealth dicing exhibits better heat resistance, the value of H _{105°C-200°C} /H _30°C-100°C is particularly preferably 0.7 or more, and more preferably 1.5 or more. In addition, there is no particular restriction on the upper limit of the value of _{H 105°C-200°C} /H _{30°C-100°C, but it is generally preferably 20 or less.}

In the adhesive sheet for invisible cutting of this embodiment, the tensile elastic modulus of the substrate at 23° C. is preferably 450 MPa or less, especially 400 MPa or less, and more preferably 300 MPa or less. In addition, the tensile modulus of elasticity is preferably 50 MPa or more, particularly preferably 70 MPa or more, and more preferably 100 MPa or more.

With the coefficient of tensile elasticity of 450 MPa or less, the substrate is likely to shrink due to heating. Therefore, after the thermal shrinkage, the semiconductor wafer and the glass wafer can be effectively maintained in a separated state. On the other hand, when the tensile modulus of elasticity is 50 MPa or more, the base material has sufficient rigidity, and the adhesive sheet for stealth dicing provided with the base material is excellent in processability and handling properties. In addition, the details of the method for measuring the coefficient of tensile elasticity are as described in the test example described later.

As the material of the base material, it is not particularly limited as long as it satisfies the relationship of the above-mentioned formula (1) for the measurement performed by the thermomechanical analysis device, and at the same time performs the desired function in the use step of the adhesive sheet for invisible dicing. . In addition, when the adhesive layer is composed of an energy-ray curable adhesive, the material of the base material is preferably capable of exhibiting good penetration of energy rays irradiated for curing of the adhesive layer.

The substrate is preferably a resin film mainly made of a resin-based material. Specific examples thereof include polyethylene film, polypropylene film, polybutene film, polybutadiene film, and polymethylpentene film. , Polyolefin-based films such as ethylene-norbornene copolymer films, norbornene resin films; ethylene-(meth)acrylic acid copolymer films, ethylene-methyl(meth)acrylate copolymer films, other ethylene-( Ethylene copolymer films such as meth)acrylate copolymer films; ethylene-vinyl acetate copolymer films; polyvinyl chloride films such as polyvinyl chloride films and vinyl chloride copolymer films; (meth)acrylate copolymer films Material film; polyurethane film; polystyrene film; fluororesin film; polyimide film; polycarbonate film, etc. In the polyolefin-based film, the polyolefin may be a block copolymer or a random copolymer. Examples of polyethylene films include low-density polyethylene (LDPE) films, linear low-density polyethylene (LLDPE) films, high-density polyethylene (HDPE) films, and the like. In addition, modified films such as crosslinked films and ionic polymer films can also be used. In addition, the substrate may be a laminated film obtained by laminating several layers of the above-mentioned films. In this laminated film, the materials constituting each layer may be of the same kind or different kinds. In addition, in this specification, "(meth)acrylic acid" means both acrylic acid and methacrylic acid. The same applies to other similar terms.

As the substrate, among the above-mentioned films, considering that it is easy to meet the relationship of the above-mentioned formula (1) for the measurement by a thermomechanical analysis device, it is preferable to use a low-density polyethylene film, a linear low-density polyethylene film, or a non-linear low-density polyethylene film. A polypropylene film (atactic polypropylene film) or an ethylene-methacrylic acid copolymer film of a regular copolymer is ideal.

The base material may also contain various additives such as flame retardants, plasticizers, antistatic agents, lubricants, antioxidants, colorants, infrared absorbers, and ion trapping agents. The content of these additives is not particularly limited, but it is preferably set in a range where the substrate exerts a desired function.

In order to improve the adhesion with the adhesive layer on the side of the substrate on which the adhesive layer is laminated, surface treatments such as primer treatment, corona treatment, and plasma treatment can also be applied.

The thickness of the substrate is preferably 450 μm or less, especially 400 μm or less, and more preferably 350 μm or less. In addition, the thickness is preferably 20 μm or more, particularly 25 μm or more, and more preferably 50 μm or more. Since the thickness of the substrate is 450μm or less, the substrate is easily thermally contracted, and the semiconductor wafers and glass wafers can be well separated and maintained. In addition, since the thickness of the substrate is 20 μm or more, the substrate has good rigidity, and the adhesive sheet for stealth dicing can effectively support the object to be processed.

(2) Adhesive layer

In the adhesive sheet for stealth dicing of the present embodiment, the adhesive layer is not particularly limited as long as it can perform a desired function in the use step of the adhesive sheet for stealth dicing. The adhesive sheet for stealth dicing is provided with an adhesive layer, so that the object to be processed can be easily attached to the surface of the adhesive layer.

The adhesive layer may be composed of a non-energy-ray-curable adhesive or may be composed of an energy-ray-curable adhesive. As a non-energy-ray-curable adhesive, one having the desired adhesive strength and releasability is preferred, and it can be used, for example, acrylic adhesive, rubber adhesive, silicone adhesive, urethane Adhesives, polyester adhesives, polyvinyl ether adhesives, etc. Among them, an acrylic adhesive that can effectively suppress the peeling of semiconductor wafers and the like when the adhesive sheet for stealth dicing is stretched is preferable.

On the other hand, energy-ray-curable adhesives are hardened by energy ray irradiation, and the adhesive force is reduced. Therefore, when you want to separate the semiconductor wafer from the adhesive sheet for invisible dicing, it can be easily separated by irradiating energy rays. .

The energy ray curable adhesive constituting the adhesive layer may be a polymer with energy ray curability as the main component, or a non-energy ray curable polymer (polymer without energy ray curability) A mixture with at least one or more monomers and/or oligomers having energy ray-curable groups as the main component. In addition, it may be a mixture of an energy-ray-curable polymer and a non-energy-ray-curable polymer, or it may be an energy-ray-curable polymer and at least one monomer having an energy-ray-curable group. And/or a mixture of oligomers may also be a mixture of these three types.

First, the case where the energy ray curable adhesive is mainly composed of a polymer having energy ray curability is explained as follows.

The energy-ray-curable polymer is preferably a (meth)acrylate (co)polymer (A) having energy-ray-curable functional groups (energy-ray-curable groups) introduced into the side chain It is called "energy ray hardening polymer (A)"). The energy ray-curable polymer (A) is preferably an acrylic copolymer (a1) having a functional group-containing monomer unit and an unsaturated group-containing compound having a functional group bonded to the functional group (a2) The result of the reaction.

The acrylic copolymer (a1) preferably contains a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth)acrylate monomer or a derivative thereof.

The functional group-containing monomer as the structural unit of the acrylic copolymer (a1) preferably has a polymerizable double bond in the molecule, and a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, and an epoxy group. The monomer.

Examples of hydroxyl-containing monomers include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and (meth)acrylic acid. 2-hydroxybutyl, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc., can be used individually by 1 type or in combination of 2 or more types of these.

Examples of carboxyl group-containing monomers include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These can be used individually by 1 type or in combination of 2 or more types.

Examples of the amine group-containing monomer or the substituted amine group-containing monomer include, for example, aminoethyl (meth)acrylate, n-butylaminoethyl (meth)acrylate, and the like. These can be used individually by 1 type or in combination of 2 or more types.

As the (meth)acrylate monomer constituting the acrylic copolymer (a1), in addition to the alkyl (meth)acrylate having 1 to 20 carbon atoms in the alkyl group, it can be suitably used. For example, it has Monomers with alicyclic structure (monomers with alicyclic structure).

As alkyl (meth)acrylates, particularly alkyl (meth)acrylates with an alkyl group of 1 to 18 carbon atoms, they can be suitably used, for example, methyl (meth)acrylate, ethyl (meth)acrylate Ester, propyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. These can be used individually by 1 type or in combination of 2 or more types.

As the alicyclic structure-containing monomer, it can be suitably used, for example, cyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, adamantyl (meth)acrylate, (meth)acrylic acid Isocamphor, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, etc. are preferable. These can be used individually by 1 type or in combination of 2 or more types.

The acrylic copolymer (a1) preferably contains a constituent unit derived from the functional group-containing monomer at a ratio of 1% by mass or more, particularly preferably 5% by mass or more, and still more preferably 10% by mass or more. Furthermore, the acrylic copolymer (a1) preferably contains a constituent unit derived from the functional group-containing monomer at a ratio of preferably 35% by mass or less, particularly preferably 30% by mass or less, and still more preferably 25% by mass or less. .

The acrylic copolymer (a1) is preferably 50% by mass or more, particularly preferably 60% by mass or more, and more preferably 70% by mass or more, containing a (meth)acrylate monomer or derivative thereof The constituent unit. Furthermore, the acrylic copolymer (a1) is preferably 99% by mass or less, particularly preferably 95% by mass or less, and still more preferably 90% by mass or less, containing a (meth)acrylate monomer or its The building blocks of derivatives.

Acrylic copolymer (a1) can be obtained by copolymerizing the above-mentioned functional group-containing monomer with (meth)acrylate monomer or its derivative according to the usual method, but in addition to these monomers , Dimethyl acrylamide, vinyl formate, vinyl acetate, styrene, etc. can also be copolymerized.

By reacting the above-mentioned acrylic copolymer (a1) having a functional group-containing monomer unit with an unsaturated group-containing compound (a2) having a functional group bonded to the functional group, an energy ray curable type can be obtained Polymer (A).

The functional group possessed by the unsaturated group-containing compound (a2) can be appropriately selected according to the type of the functional group of the functional group-containing monomer unit possessed by the acrylic copolymer (a1). For example, when the functional group possessed by the acrylic copolymer (a1) is a hydroxyl group, an amino group or a substituted amino group, the functional group possessed by the unsaturated group-containing compound (a2) is preferably an isocyanate group or an epoxy group. When the functional group possessed by the copolymer (a1) is an epoxy group, the functional group possessed by the unsaturated group-containing compound (a2) is preferably an amino group, a carboxyl group, or an aziridinyl group.

In addition, in the above-mentioned unsaturated group-containing compound (a2), there are at least one in one molecule, preferably 1 to 6, and more preferably 1 to 4 energy ray polymerizable carbon-carbon double bonds. As specific examples of such an unsaturated group-containing compound (a2), for example, 2-methacryloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate, methyl Acrylic isocyanate, allyl isocyanate, 1,1-(bisacryloxymethyl) ethyl isocyanate; obtained by the reaction of a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate Acrylic monoisocyanate compound; Acrylic monoisocyanate compound obtained by reaction of diisocyanate compound or polyisocyanate compound, polyol compound, and hydroxyethyl (meth)acrylate; (meth) acrylic epoxy Propyl ester; (meth)acrylic acid, (meth)acrylic acid 2-(1-aziridinyl) ethyl ester, 2-vinyl-2-oxazoline (2-vinyl-2-oxazoline), 2- 2-isopropenyl-2-oxazoline etc. (2-isopropenyl-2-oxazoline).

The number of moles of the unsaturated group-containing compound (a2) relative to the functional group-containing monomer of the acrylic copolymer (a1) is preferably 50 mole% or more, particularly preferably 60 mole% or more , It is more preferable to use at a ratio of 70 mol% or more. In addition, the number of moles of the above-mentioned unsaturated group-containing compound (a2) relative to the functional group-containing monomer of the above-mentioned acrylic copolymer (a1) is preferably 95 mole% or less, particularly preferably 93 moles % Or less, more preferably 90 mol% or less.

In the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), it can be based on the difference between the functional group possessed by the acrylic copolymer (a1) and the functional group possessed by the unsaturated group-containing compound (a2) Combinations, and appropriately select the reaction temperature, pressure, solvent, time, presence or absence of catalyst, and type of catalyst. Thereby, the functional group existing in the acrylic copolymer (a1) reacts with the functional group in the unsaturated group-containing compound (a2), and the unsaturated group is introduced into the side chain in the acrylic copolymer (a1) to obtain Energy ray hardening polymer (A).

The weight average molecular weight (Mw) of the energy ray-curable polymer (A) obtained in this way is preferably 10,000 or more, particularly preferably 150,000 or more, and further preferably 200,000 or more. In addition, the weight average molecular weight (Mw) is preferably 1.5 million or less, particularly preferably 1 million or less. In addition, the weight average molecular weight (Mw) in this specification is a conversion value of standard polystyrene measured by gel permeation chromatography (GPC method).

Energy ray hardenable adhesive, even when energy ray hardenable polymer such as energy ray hardenable type (A) is used as the main component, the energy ray hardenable adhesive can further contain energy ray hardenable monomer And/or oligomer (B).

As the energy ray-curable monomer and/or oligomer (B), for example, esters of polyol and (meth)acrylic acid can be used.

As the energy ray-curable monomer and/or oligomer (B), for example, monofunctional acrylates such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and trihydroxy acrylates can be used. Trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate acrylate), dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate , Polyethylene glycol di(meth)acrylate, dimethylol tricyclodecane di(meth)acrylate, etc. Acrylates, polyester oligo(meth)acrylate, polyurethane oligo(meth)acrylate, etc.

When energy-ray-curable polymer (A) is blended with energy-ray-curable monomer and/or oligomer (B), the energy-ray-curable monomer and/or oligomer (B) The amount in the radiation-curable adhesive is preferably more than 0 parts by mass relative to 100 parts by mass of the energy ray-curable polymer (A), and more preferably 60 parts by mass or more. In addition, the content is preferably 250 parts by mass or less with respect to 100 parts by mass of the energy ray-curable polymer (A), particularly preferably 200 parts by mass or less.

Here, when using ultraviolet rays as the energy ray to harden the energy-ray curable adhesive, it is better to add a photopolymerization initiator (C). By using this photopolymerization initiator (C), the polymerization curing time can be reduced And the amount of light exposure.

As the photopolymerization initiator (C), specific examples include benzoin, acetophenone, benzoin, benzoin methyl ether, and benzoin ethyl ether. ), benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin benzoate methyl, Benzoin dimethyl ketal (benzoin dimethyl ketal), 2,4-diethylthioxanthone (2,4-diethylthioxanthone), 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide (benzyl diphenyl sulfide) sulfide), tetramethylthiuram monosulfide, azobisisobutyronitrile, benzil, dibenzil, diethyl thiuram (diacetyl), β-croll anthraquinone, (2,4,6-trimethylbenzyldiphenyl) phosphine oxide ((2,4,6-trimethylbenzyldiphenyl) phosphine oxide), 2- Benzothiazole-N,N-diethyl dithiocarbamate (2-benzothiazole-N,N-diethyl dithiocarbamate), oligo{2-hydroxy-2-methyl-1-[4-(1-propylene) Yl)phenyl]acetone)(oligo{2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl]propanone}), 2,2-dimethoxy-1,2-diphenyl Ethane-1-one (2,2-Dimethoxy-1,2-diphenylethane-1-one) and so on. These may be used alone, or two or more of them may be used in combination.

The photopolymerization initiator (C) is relative to the energy ray hardenable copolymer (A) (when an energy ray hardenable monomer and/or oligomer (B) is blended, it is an energy ray hardenable copolymer ( A) and 100 parts by mass of the total amount of the energy ray-curable monomer and/or oligomer (B) (100 parts by mass) are preferably used in an amount of 0.1 parts by mass or more, particularly preferably 0.5 parts by mass or more. In addition, the photopolymerization initiator (C) is relative to the energy ray curable copolymer (A) (when an energy ray curable monomer and/or oligomer (B) is blended, it is an energy ray curable copolymer The total amount of the substance (A) and the energy ray-curable monomer and/or oligomer (B) (100 parts by mass)) 100 parts by mass, preferably 10 parts by mass or less, particularly preferably 6 parts by mass or less use.

In the energy ray-curable adhesive, other components may be appropriately blended in addition to the above-mentioned components. As other components, for example, a non-energy ray-curable polymer component or an oligomer component (D), a crosslinking agent (E), and the like can be cited.

Examples of non-energy-ray-curable polymer components or oligomer components (D) include polyacrylates, polyesters, polyurethanes, polycarbonates, polyolefins, etc. The weight average molecular weight (Mw) is preferably 30 to 2.5 million polymers or oligomers. By blending the component (D) with an energy-ray curable adhesive, the adhesiveness and peelability before curing, the strength after curing, the adhesion to other layers, storage stability, etc. can be improved. The blending amount of the component (D) is not particularly limited, and can be appropriately determined within the range of more than 0 parts by mass and 50 parts by mass relative to 100 parts by mass of the energy ray curable copolymer (A).

As the crosslinking agent (E), a polyfunctional compound having reactivity with the functional group possessed by the energy ray curable copolymer (A) or the like can be used. Examples of such polyfunctional compounds include, for example, isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, and oxalamine compounds. Oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, reactive phenolic resins, etc.

The blending amount of the crosslinking agent (E) is preferably 0.01 parts by mass or more relative to 100 parts by mass of the energy ray curable copolymer (A), especially 0.03 parts by mass or more, and further 0.04 parts by mass or more good. In addition, the blending amount of the crosslinking agent (E) is preferably 8 parts by mass or less, particularly preferably 5 parts by mass or less, and further 3.5 parts by mass relative to 100 parts by mass of the energy ray curable copolymer (A) The following is better.

Next, for the case where the energy ray curable adhesive is mainly composed of a mixture of a non-energy ray curable polymer component and a monomer and/or oligomer having at least one energy ray curable group, the following is explained .

As the non-energy-ray curable polymer component, for example, the same component as the aforementioned acrylic copolymer (a1) can be used.

As the monomer and/or oligomer having at least one or more energy ray-curable groups, the same as the aforementioned component (B) can be selected. In terms of the blending ratio of the non-energy-ray-curable polymer component and the monomer and/or oligomer having at least one energy-ray-curable group, it is 100% relative to the non-energy-ray-curable polymer component. Parts by mass, monomers and/or oligomers having at least one energy ray-curable group are preferably at least 1 part by mass, especially at least 60 parts by mass. Moreover, the blending ratio is relatively Based on 100 parts by mass of the non-energy-ray curable polymer component, monomers and/or oligomers having at least one energy-ray curable group are preferably 200 parts by mass or less, especially 160 parts by mass or less. good.

In this case, similarly to the above, the photopolymerization initiator (C) and the crosslinking agent (E) may be appropriately blended.

The thickness of the adhesive layer is preferably 1 μm or more, especially 2 μm or more, and more preferably 3 μm or more. In addition, the thickness is preferably 50 μm or less, particularly 30 μm or less, and more preferably 20 μm or less. When the thickness of the adhesive layer is 1 μm or more, the adhesive sheet for stealth dicing can exhibit good adhesion to the object to be processed, and it is possible to effectively suppress the peeling of the object to be processed in an undesired stage. In addition, when the thickness of the adhesive layer is 50 μm or less, the adhesive force of the adhesive sheet for stealth dicing can be prevented from becoming too high, and the occurrence of pick-up failure can be effectively suppressed.

(3) Peel off the board

In the adhesive sheet for stealth dicing of this embodiment, until the adhesive surface of the adhesive layer is attached to the object to be processed, in order to protect the surface, the sheet may be peeled from the area layer. The composition of the release sheet is arbitrary, and a plastic film can be exemplified by a release treatment with a release agent or the like. Specific examples of plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, as well as polypropylene, polyethylene, etc. Of polyolefin film. As the release agent, a silicone-based, fluorine-based, long-chain alkyl-based, etc. can be used, and among these, a silicone-based low-cost and stable performance is preferred. The thickness of the release sheet is not particularly limited, but it is usually 20 μm or more and 250 μm or less.

2. Manufacturing method of adhesive plates for invisible cutting

In the adhesive sheet for stealth dicing of this embodiment, the manufacturing method of the substrate is not particularly limited as long as the method of manufacturing the substrate can meet the relationship of the above-mentioned formula (1) related to the measurement of the obtained substrate by the thermomechanical analysis device. For example, the aforementioned materials can be used to manufacture the base material by melt extrusion methods such as T-die method and round die method; roller compaction method; dry method, wet method and other solution methods. Among these manufacturing methods, the T-die method is more desirable.

In addition, in the adhesive sheet for stealth dicing of this embodiment, the method of forming the adhesive layer is not particularly limited. For example, the adhesive sheet for invisible dicing can be obtained by transferring the adhesive layer formed on the release sheet to the one-sided side of the base material manufactured in the above-mentioned manner. In this case, by preparing a coating solution containing an adhesive composition that constitutes the adhesive layer and optionally a solvent or dispersion medium, it can be applied to the peeled surface of the peeling sheet (hereinafter sometimes referred to as "Peeling surface"), use a die coater, curtain coater, sprayer, slit coater, knife coater, etc. to apply the coating solution to form a coating film, and then dry the coating film to form an adhesive Floor. The coating solution is not particularly limited as long as it can be applied, and its properties are not particularly limited. The components used to form the adhesive layer may be contained as a solute or as a dispersant. The release sheet in this laminate can be peeled off as a step material, and it can also be used to protect the adhesive surface of the adhesive layer until the invisible cutting adhesive sheet is attached to the object to be processed.

When the coating solution used to form the adhesive layer contains a cross-linking agent, the drying conditions (temperature, time, etc.) can be changed or additional heating treatment can be used to make the energy ray-curable polymer in the coating film ( A) or the cross-linking reaction between the non-energy-ray-curable polymer component and the cross-linking agent (E) proceeds, and a cross-linked structure is formed in the adhesive layer at a desired density. In order to make this crosslinking reaction fully proceed, after laminating the adhesive layer on the base material according to the above method etc., the obtained adhesive sheet for stealth dicing can be carried out, for example, in an environment of 23°C and 50% relative humidity. Leave it to mature for a few days.

Instead of transferring the adhesive layer formed on the release sheet to one side of the substrate as described above, the adhesive layer may be directly formed on the substrate. In this case, a coating film is formed by applying the coating solution for forming the aforementioned adhesive layer on one side of the substrate, and the coating film is dried to form the adhesive layer.

3. How to use the adhesive plate for invisible cutting

The adhesive sheet for invisible cutting of this embodiment can be used for invisible cutting. In addition, the adhesive sheet for stealth dicing of this embodiment can be used in a method of manufacturing a semiconductor device having a step of stealth dicing.

The adhesive sheet for stealth dicing of the present embodiment can suppress collision of wafers after heat shrinkage as described above, and therefore can be suitably used for processing objects whose thickness is thin and wafer breakage is likely to occur. For example, the adhesive sheet for stealth dicing of this embodiment can be suitably used for a semiconductor wafer (TSV) having a through electrode.

The following describes an example of a method of manufacturing a semiconductor device with a step of stealth dicing. First, a step of backgrinding one side of the object to be processed (semiconductor wafer) fixed on a hard support is performed. The semiconductor wafer is fixed to a hard support by, for example, an adhesive. As the rigid support, for example, glass or the like can be used. The back grinding can be performed by a general method.

Then, the semiconductor wafer that has been polished back is transferred from the hard support to the adhesive sheet for stealth dicing. At this time, after bonding the back-polished surface of the semiconductor wafer and the surface on the adhesive layer side of the invisible dicing adhesive sheet, the hard support is separated from the semiconductor wafer. The separation of the hard support from the semiconductor wafer can be implemented in accordance with the type of adhesive used to fix the hard support to the semiconductor wafer. For example, the hard support is removed from the semiconductor after the adhesive is softened by heating. The method of wafer sliding; the method of using laser light to decompose the adhesive, etc. In addition, after separating the semiconductor wafer from the hard support, the peripheral portion of the adhesive sheet for stealth dicing is attached to the ring frame.

Then, the semiconductor wafer laminated on the adhesive sheet for stealth dicing is cleaned with a solvent. In this way, the adhesive remaining on the semiconductor wafer can be removed. The cleaning can be carried out by a general method, for example, a method of immersing a laminate of an adhesive sheet for stealth dicing and a semiconductor wafer in a solvent; a frame slightly larger than the semiconductor wafer is arranged around the wafer The method of putting a solvent into the frame on the adhesive plate for invisible cutting, etc.

Then, as needed, another semiconductor wafer can be layered on the semiconductor wafer that has been layered on the adhesive sheet for stealth dicing. At this time, the semiconductor wafers can be fixed to each other with adhesives, for example, you can use Non-conductive adhesive film (Nonconductive film; NCF) is fixed. The build-up of semiconductor wafers can be repeated until the necessary number of build-ups is reached. Such a build-up of semiconductor wafers is particularly suitable for use when manufacturing build-up circuits using TSV wafers as semiconductor wafers.

Then, the semiconductor wafer or the laminate of semiconductor wafers implemented on the adhesive sheet for stealth dicing (hereinafter referred to as "semiconductor wafer", unless otherwise specified, refers to the semiconductor wafer or laminate of semiconductor wafers) The invisible cutting. In this step, the semiconductor wafer is irradiated with laser light to form a modified part in the semiconductor wafer. The laser light can be irradiated with the equipment and conditions generally used in invisible cutting.

Then, the semiconductor wafer is divided in the modified part formed by stealth dicing to obtain a plurality of semiconductor wafers. The division can be performed by, for example, placing a laminate of an adhesive sheet for stealth dicing and a semiconductor wafer in an expansion device, and expanding it under an environment of 0° C. to room temperature.

Then, the invisible cutting adhesive sheet is expanded again. The main purpose of this expansion is to separate the obtained semiconductor wafers from each other. Furthermore, maintaining the expanded state, the adhesive sheet for stealth cutting is adsorbed by the suction table. The expansion here can be carried out at room temperature or under heating. In addition, the expansion can be performed by a general method using a general device, and the adsorption table used can also be performed by using a general one.

Then, while maintaining the state in which the adhesive sheet for stealth dicing is adsorbed by the suction table, the area of the unlaminated semiconductor wafer in the obtained adhesive sheet for stealth dicing on which the semiconductor wafer is laminated is heated to shrink (thermal shrinkage). Specifically, the area between the laminated semiconductor wafer in the adhesive sheet for invisible dicing and the area between the area where the ring frame is attached in the adhesive sheet for invisible dicing is heated to shrink the area. As the heating conditions at this time, the temperature of the adhesive sheet for stealth dicing is preferably 90°C or higher. In addition, the temperature of the adhesive sheet for stealth dicing is preferably 200°C or lower. In the adhesive sheet for stealth cutting of this embodiment, the change in the length of the substrate measured by the thermomechanical analysis device △L _90℃ and △L _90℃ conform to the relationship of the aforementioned formula (1), so that the substrate will be affected by It shrinks well when heated. As a result, as described later, even if the adhesive sheet for stealth dicing is released from the suction by the suction table, the semiconductor wafers are maintained in a separated state well, and the pickup of the semiconductor wafers can be performed well.

Then, the adhesive sheet for invisible cutting is sucked and released from the suction table described above. In the above heat shrinking step, the area between the laminated semiconductor wafer in the adhesive sheet for invisible dicing and the area between the area where the ring frame is attached in the adhesive sheet for invisible dicing shrinks, thereby The adhesive sheet for stealth dicing generates a force that stretches the area where the semiconductor chip is attached to the peripheral edge. As a result, even after the adhesive sheet for stealth dicing is released from the suction by the suction table, the semiconductor wafers can still be maintained in a separated state.

After that, each semiconductor wafer is picked up from the adhesive sheet for stealth dicing in a state of being separated from the adjacent semiconductor wafer. This picking can be carried out by a general method using general equipment. As described above, the adhesive sheet for stealth dicing of the present embodiment exhibits excellent heat shrinkability, and as a result, semiconductor wafers can be maintained in a good separated state, thereby enabling good picking.

The embodiments described above are described to facilitate the understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiment also includes all design changes and equivalents belonging to the technical scope of the present invention.

For example, another layer may be provided between the substrate and the adhesive layer, or the surface of the substrate on the opposite side to the adhesive layer.

[Example]

Hereinafter, the present invention will be described in more detail using examples and the like, but the scope of the present invention is not limited to these examples and the like.

[Example 1]

(1) Production of base material

A resin composition containing low-density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., product name "SUMIKATHENE F-412-1") was applied to a small T-die extruder (manufactured by Toyo Seiki Co., Ltd., product name "LABO PLASTOMILL") Extrusion is performed to obtain a substrate with a thickness of 70 μm.

(2) Preparation of adhesive composition

Acrylic copolymer (a1) obtained by reacting 62 parts by mass of n-butyl acrylate (BA), 10 parts by mass of methyl methacrylate (MMA) and 28 parts by mass of 2-hydroxyethyl acrylate (HEA), and 80 mol% of methacryloxyethyl isocyanate (MOI) was reacted with respect to the HEA of the acrylic copolymer (a1) to obtain an energy ray-curable polymer (A). The molecular weight of this energy ray-curable polymer (A) was measured by the method described later, and the weight average molecular weight (Mw) was 500,000.

100 parts by mass of the obtained energy ray-curable polymer (in terms of solid content, the same below), and 3.0 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name "Irgacure 184") as a photopolymerization initiator 1. 1.0 part by mass of toluene diisocyanate (manufactured by Tosoh Corporation, product name "CORONATE L") as a crosslinking agent was mixed in a solvent to obtain an adhesive composition.

(3) Formation of adhesive layer

For a release sheet (manufactured by LINTEC Corporation, product name "SP-PET381031") formed by forming a silicone release agent layer on one side of a 38μm thick polyethylene terephthalate (PET) film The above-mentioned adhesive composition was applied to the release surface, and dried by heating to form an adhesive layer with a thickness of 20 μm on the release sheet.

(4) Production of adhesive plates for invisible cutting

The adhesive layer formed in the above step (3) and the side opposite to the release sheet are bonded to the single side of the base material produced in the above step (1) to obtain an adhesive sheet for invisible cutting.

[Example 2]

As a base material, a resin composition containing low-density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., product name "SUMIKATHENE F-723P") was used, and a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "LABO PLASTOMILL") was used. ") Extrusion molding was performed to obtain a base material having a thickness of 70 μm, except for this, the same procedure as in Example 1 was performed to obtain an adhesive sheet for stealth dicing.

[Example 3]

As a base material, a resin composition containing low-density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., product name "SUMIKATHENE CE3506") is used with a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "LABO PLASTOMILL") Extrusion molding was performed to obtain a base material having a thickness of 70 μm. Except for this, the same procedure as in Example 1 was carried out to obtain an adhesive sheet for stealth dicing.

[Example 4]

As a base material, a resin composition containing random polypropylene (manufactured by PRIME POLYMER, product name "PRIME TPO J-5710") was used, and a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd. product name "LABO") was used. PLASTOMILL") Extrusion molding was performed to obtain a base material having a thickness of 70 μm. Except for this, the same procedure as in Example 1 was carried out to obtain an adhesive sheet for stealth dicing.

[Example 5]

As a base material, a resin composition containing random polypropylene (manufactured by PRIME POLYMER, product name "PRIME F-3740") was used, and a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd. product name "LABO PLASTOMILL") was used. ") Extrusion molding was performed to obtain a base material having a thickness of 70 μm, except for this, the same procedure as in Example 1 was performed to obtain an adhesive sheet for stealth dicing.

[Example 6]

As the base material, a resin composition containing an ethylene-methacrylic acid copolymer (manufactured by Mitsui Dupont polychemical, product name "NUCREL NH903C") was used with a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name " LABO PLASTOMILL") was extruded to obtain a substrate with a thickness of 70 μm, except that it was carried out in the same manner as in Example 1 to obtain an adhesive sheet for invisible dicing.

[Comparative Example 1]

As the base material, a polybutylene terephthalate film having a thickness of 80 μm was used. Except for this, the same procedure as in Example 1 was carried out to obtain an adhesive sheet for stealth dicing.

Here, the aforementioned weight average molecular weight (Mw) is a weight average molecular weight in terms of polystyrene obtained by measuring (GPC) using gel permeation chromatography (GPC) under the following conditions.

<Measurement conditions>

‧GPC measuring device: manufactured by Tosoh Corporation, HLC-8020

‧GPC string (pass in the following order): manufactured by Tosoh Corporation

TSK protection column HXL-H

TSK gel GMHXL(×2)

TSK gel G2000HXL

‧Measuring solvent: Tetrahydrofuran

‧Measuring temperature: 40℃

[Test Example 1] (Measurement of the coefficient of tensile elasticity of the substrate)

The substrates produced in the Examples and Comparative Examples were cut into 15mm×140mm test pieces, and the tensile elasticity coefficient was measured at a temperature of 23° C. and a relative humidity of 50% in accordance with JIS K7161: 2014. Specifically, the above-mentioned test piece was subjected to a tensile tester (manufactured by ORIENTEC, product name "TENSILON RTA-T-2M"), and the distance between the chucks was set to 100 mm, and then the tensile test was performed at a speed of 200 mm/min. , Determine the coefficient of tensile elasticity. In addition, the measurement is performed on both the extrusion direction (MD) and the direction at right angles (CD) when the base material is formed, and the average value of these measurement results is defined as the tensile elasticity coefficient of elongation at break. The results are shown in Table 1.

[Experimental example 2] (Measurement by differential scanning calorimeter)

A 4.0 mg portion was cut out from the base materials prepared in the Examples and Comparative Examples and used as a measurement sample. This measurement sample was heated from 0°C to 200°C at a temperature increase rate of 10°C/min using a differential scanning calorimeter (manufactured by TA Instruments, product name "Q2000") to obtain a DSC curve.

Set the measured value (mW) at 25°C in the obtained DSC curve as H _25°C , and set the minimum value of the measured value (mW) in the range of 30°C to 100°C as H _30°C-100°C . The minimum value of the measured value (mW) in the range of 105°C to 200°C is set to H _{105°C-200°C} . These results are shown in Table 1.

And, calculating H _{30 ℃ -100 ℃ 25 deg.] C} with respect to the ratio of H _{(H 30 ℃ -100 ℃ / H} 25 ℃), H 105 ℃ -200 ℃ _{25 deg.] C} with respect to the ratio of H (H _{105 ℃ -200 ℃} / H _{25 ℃),} and H _{105 ℃ -200 ℃ -100 ℃} with respect to the ratio of H _{(H 105 ℃ -200 ℃ / H} 30 ℃ -100 ℃) 30 ℃. These results are shown in Table 1.

[Experimental example 3] (Measurement by thermomechanical analysis device)

The base materials prepared in the Examples and Comparative Examples were cut into a size of 4.5 mm×20 mm, and used as measurement samples. Put the measurement sample in a thermomechanical analyzer (manufactured by BRUKER, product name "TMA 4000SA"), set the distance between the chucks to 15mm, and heat it from 25°C to 120°C at a temperature increase rate of 20°C/min. A load of 0.2g stretches in the long axis direction. And, measure the distance between the chucks of the measurement sample at 60°C and 90°C, respectively.

And, subtract the initial distance between the chucks of the measured sample at 60°C from the distance between the chucks to calculate the change in the distance between the chucks of the measured sample ΔL _60°C (μm). Also, subtract the initial distance between the chucks from the distance between the chucks of the measured sample at 90°C to calculate the change in the distance between the chucks of the measured sample ΔL _90°C (μm). Then calculate △ L _{90 ℃} △ L a value obtained by subtracting _{60 ℃ (△ L 90 ℃ -} △ L 60 ℃) (μm). These results are shown in Table 1.

[Test Example 4] (Evaluation of Heat Resistance)

After peeling the release sheet from the adhesive sheet for invisible dicing manufactured in the examples and comparative examples, the substrate side surface of the adhesive sheet for invisible dicing was adsorbed on a multi-wafer holder (manufactured by LINTEC, product name) "RAD-2700 F/12") is equipped with the adsorption table for 2 minutes. During the adsorption period, the adsorption table is heated to 70°C.

After 2 minutes, the suction by the suction table is stopped, and then the transport mechanism of the multi-wafer rack is driven to separate the adhesive sheet for stealth dicing from the suction table. At this time, the separation proceeded well, and those who could transport the adhesive plate for invisible cutting were rated as "○", and there was a little adhesion of the adhesive plate for invisible cutting to the porous table, but the adhesive plate for invisible cutting could be transported. The film was rated as "△", and the adhesive plate for invisible cutting was completely adhered to the porous table, and the adhesive plate for invisible cutting could not be transported was rated as "×". The heat resistance of the adhesive plate for invisible cutting was evaluated. The results are shown in Table 1.

The above heat resistance evaluation was also performed for the case where the adsorption table was heated to 90°C. The results are shown in Table 1.

[Test Example 5] (Evaluation of Thermal Shrinkage)

The peeling plate was peeled from the adhesive plate for stealth dicing manufactured in the Examples and Comparative Examples, and the adhesive surface of the exposed adhesive layer was used with a multi-wafer holder (manufactured by LINTEC, product name "RAD-2700 F/12 "), attached to a silicon wafer (outer diameter: 8 inches, thickness: 100μm) and ring frame (stainless steel).

Then, using a laser saw (manufactured by DISCO, product name "DFL7361") on the above-mentioned silicon wafer attached to the adhesive plate for invisible dicing, laser light with a wavelength of 1342nm was irradiated to obtain a wafer size of 8mm× In the 8mm method, the modified part is formed in the silicon wafer.

Then, the silicon wafer irradiated with the laser light to which the adhesive sheet for invisible dicing is attached, and the ring frame are set in a separating and expanding machine (manufactured by DISCO, product name "DDS 2300"), and then pulled down at 0°C Expansion (cold expansion) at a speed of 100mm/sec and an expansion amount of 10mm. Thereby, the semiconductor wafer is divided in the reforming part, and a plurality of semiconductor wafers each having a wafer size of 8 mm×8 mm are obtained.

Then, the adhesive sheet for stealth cutting was expanded at a pull-down speed of 1 mm/sec and an expansion amount of 7 mm. Furthermore, after maintaining the expanded state, the invisible dicing adhesive sheet is sucked by the suction table, and then the region of the invisible dicing adhesive sheet to which the semiconductor wafer is attached and the area to which the ring frame is attached is heated. The heating conditions at this time are: the set temperature of the IR heater is 600°C, the rotation speed is 1 deg/sec, and the distance between the suction table and the heater for the adhesive plate for invisible cutting is set to 13 mm. Thereby, the adhesive sheet for invisible cutting is heated to about 180°C.

After that, the adhesive sheet for stealth dicing was released from the suction by the suction table, and the distance between adjacent semiconductor wafers was measured at 5 points, and the average value was calculated. Then, when the average value was 20 μm or more, it was rated as "○", and when the average value was less than 20 μm, it was rated as "×", and the heat shrinkability was evaluated. The results are shown in Table 1.

It can be seen from Table 1 that the adhesive sheets for stealth dicing obtained in the examples have excellent heat shrinkability. In addition, the adhesive sheets for stealth dicing obtained in Examples 1 to 3 are also excellent in heat resistance.

[Industrial Utilization]

The adhesive sheet for invisible dicing of the present invention can be suitably used in invisible dicing of semiconductor wafers with through electrodes.

Claims (6)

An adhesive sheet for invisible cutting, which is an adhesive sheet for invisible cutting provided with a substrate and an adhesive layer laminated on one side of the substrate. The adhesive sheet is characterized in that the substrate is analyzed by thermomechanical analysis. The device is heated from 25°C to 120°C at a heating rate of 20°C/min, and the substrate is stretched with a load of 0.2g, and the length of the substrate at 60°C is subtracted from the initial length of the substrate. The length change of the substrate is set to △L _60℃ , and the length of the substrate obtained by subtracting the initial length of the substrate from the length of the substrate at _90℃ is set to △L 90℃. The relationship of the following formula (1): △L _90℃ -△L _60℃ <0μm...(1), the substrate is heated from 0℃ to 200℃ at a heating rate of 10℃/min using a differential scanning calorimeter In the obtained DSC curve for the substrate, the minimum value of the measured value in the range of 30°C to 100°C is set to H _30°C-100°C , and the measured value at _{25°C is set to H 25°C} When it meets the relationship of the following formula (2): H _30℃-100℃ /H _25℃ ≦4.0...(2). An adhesive sheet for invisible cutting, which is an adhesive sheet for invisible cutting provided with a substrate and an adhesive layer laminated on one side of the substrate. The adhesive sheet is characterized in that the substrate is analyzed by thermomechanical analysis. The device is heated from 25°C to 120°C at a heating rate of 20°C/min, and the substrate is stretched with a load of 0.2g, and the length of the substrate at 60°C is subtracted from the initial length of the substrate. The length change of the substrate is set to △L _60℃ , and the length of the substrate obtained by subtracting the initial length of the substrate from the length of the substrate at _90℃ is set to △L 90℃. The relationship of the following formula (1): △L _90℃ -△L _60℃ <0μm...(1), where the substrate is heated from 0℃ to 0℃ at a heating rate of 10℃/min using a differential scanning calorimeter In the DSC curve obtained at 200°C for the substrate, the minimum value of the measured value in the range of 105°C to 200°C is set to H _{105°C-200°C} , and the measured value at 25°C is set to H _{At 25°C} , it conforms to the relationship of the following formula (3): H _{105°C-200°C} /H _25°C ≧1.0...(3). An adhesive sheet for invisible cutting, which is an adhesive sheet for invisible cutting provided with a substrate and an adhesive layer laminated on one side of the substrate. The adhesive sheet is characterized in that the substrate is analyzed by thermomechanical analysis. The device is heated from 25°C to 120°C at a heating rate of 20°C/min, and the substrate is stretched with a load of 0.2g, and the length of the substrate at 60°C is subtracted from the initial length of the substrate. The length change of the substrate is set to △L _60℃ , and the length of the substrate obtained by subtracting the initial length of the substrate from the length of the substrate at _90℃ is set to △L 90℃. The relationship of the following formula (1): △L _90℃ -△L _60℃ <0μm...(1), where the substrate is heated from 0℃ to 0℃ at a heating rate of 10℃/min using a differential scanning calorimeter In the DSC curve obtained at 200°C for the substrate, the minimum value of the measured value in the range of 30°C to 100°C is set to H _30°C-100°C , and it will be in the range of 105°C to 200°C When the minimum value of the measured value is set to H _{105℃-200℃} , it conforms to the relationship of the following formula (4): H _{105℃-200℃} /H _30℃-100℃ ≧0.1...(4). For example, the adhesive sheet for invisible cutting of any one of items 1 to 3 in the scope of patent application, wherein the tensile elastic coefficient of the substrate at 23° C. is 50 MPa or more and 450 MPa or less. For example, the adhesive sheet for stealth dicing in any one of items 1 to 3 of the scope of patent application uses a semiconductor wafer with through electrodes as the object to be processed. For example, the adhesive sheet for invisible dicing in any one of items 1 to 3 of the scope of patent application is used in the area where the object is not laminated in the adhesive sheet for invisible dicing on which the object is laminated. In the manufacturing method of the semiconductor device in the step of heating to shrink.