Method for manufacturing adhesive sheets for semiconductor processing and semiconductor devices

Abstract

The present invention relates to an adhesive sheet for semiconductor processing having a base material, a middle layer (X) having energy ray curability, and an adhesive agent layer (Y) in that order, that satisfies requirement (1). Requirement (1): using the storage modulus G'(x) (unit: MPa) of the middle layer (X) at 23°C when irradiated by ultraviolet rays at an illuminance of 230 mW / cm2 and a radiation intensity of 380 mJ / cm2 and the storage modulus G'(y) (unit: MPa) of the adhesive agent layer (Y) at 23°C, the Q value (unit: MPa) calculated by formula (1) is -30 to 30, inclusive. Q = {G'(y)-(G'(x) × 40)} … formula (1). The present invention also relates to a method for producing a semiconductor device using the adhesive sheet for semiconductor processing.

Description

[Technical Field]

[0001] This invention relates to an adhesive sheet for semiconductor processing and a method for manufacturing a semiconductor device. [Background technology]

[0002] As information terminal devices become thinner, smaller, and more multifunctional at an accelerating pace, the semiconductor devices installed in them are also required to be thinner and more densely packed, and there is a demand for thinner semiconductor wafers. Traditionally, to meet this demand, the back surface of semiconductor wafers has been ground down to make them thinner. In recent years, a method called pre-dicing has been used to obtain thin chips from semiconductor wafers (hereinafter also referred to as "wafers") by first forming grooves of a predetermined depth on the surface side of the wafer with a dicing blade, then grinding the wafer from the back side to separate the wafer into individual chips, thereby obtaining chips. As a variation of the pre-dicing method, a method has also been proposed in which a modified region is created inside the wafer using a laser, and the wafer is separated into individual chips by the stress during back-side grinding.

[0003] In each of the methods described above, backside grinding of the wafer is performed. In backside grinding of a wafer, a surface protection sheet for backside grinding (hereinafter also referred to as the "backgrind sheet") is attached to the surface of the wafer, and the process is carried out with the wafer surface protected by this sheet. The backgrind sheet is then peeled off and removed from the surface of the wafer after backside grinding. In recent years, wafers with bumps made of solder or similar materials, approximately tens to hundreds of micrometers in height, formed on their surface are sometimes used. When such bumped wafers are back-ground, a surface protection sheet is applied to the surface of the wafer where the bumps are formed, particularly to protect the bumped areas. As a surface protection sheet, for example, Patent Document 1 discloses an adhesive sheet for holding and protecting semiconductor wafers, characterized in that an intermediate layer satisfying a specific elastic modulus and gel content is provided on one side of a base layer, and an adhesive layer is formed on the surface of the intermediate layer. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 4367769 [Overview of the project] [Problems that the invention aims to solve]

[0005] Incidentally, adhesive sheets for semiconductor processing, such as surface protection sheets, are typically peeled off after being attached to a semiconductor device or similar object and the necessary processing has been carried out on the semiconductor device. Furthermore, in order to protect semiconductor devices more efficiently, or to easily peel semiconductor processing adhesive sheets from semiconductor devices, energy ray curability may be imparted to the intermediate layer and / or adhesive layer of semiconductor processing adhesive sheets. For example, Patent Document 1 describes a surface protection sheet in which the intermediate layer may contain a radiation-curable oligomer in order to slightly harden the intermediate layer when irradiated with radiation during peeling. Furthermore, Patent Document 1 describes a surface protection sheet in which the adhesive layer may be a radiation-curable adhesive layer containing a radiation-curable acrylic polymer having a carbon-carbon double bond in its molecule, from the viewpoint that a low-adhesion substance is generated when irradiated with radiation during peeling, allowing for easy peeling from the wafer. However, the intermediate layer and / or adhesive layer hardened by energy rays may change in properties compared to before being attached to the semiconductor device, potentially causing adverse effects. For example, when peeling a semiconductor processing adhesive sheet from a semiconductor device after curing an intermediate layer with energy rays, the adhesion strength between the intermediate layer and the adhesive layer may be insufficient, leading to delamination. In such cases, for example, adhesive residue may remain on the semiconductor device when the semiconductor processing adhesive sheet is peeled off, potentially contaminating the semiconductor device.

[0006] The present invention has been made in view of the above circumstances, and aims to provide a novel adhesive sheet for semiconductor processing that can suppress interlayer delamination that occurs between the intermediate layer and the adhesive layer when peeling from an adherend such as a semiconductor device. [Means for solving the problem]

[0007] The inventors of the present invention have found that the above problem can be solved by using an adhesive sheet for semiconductor processing in which the intermediate layer and the adhesive layer meet specific requirements, and have completed the present invention. In other words, the present invention provides the following [1] to

[13] . [1] An adhesive sheet for semiconductor processing having a base material, an energy ray curable intermediate layer (X), and an adhesive layer (Y) in that order, and satisfying the following requirement (1). Requirement (1): Illuminance 230mW / cm 2 , light intensity 380mJ / cm 2 Using the storage modulus G'(x) (unit: MPa) of the intermediate layer (X) at 23°C after irradiation with ultraviolet light under the specified conditions, and the storage modulus G'(y) (unit: MPa) of the adhesive layer (Y) at 23°C, the Q value (unit: MPa) calculated by the following formula (1) is between -30 and 30. Q = {G'(y) - (G'(x) × 40)} ... Equation (1) [2] The semiconductor processing adhesive sheet according to [1], wherein the storage modulus G'(x) is 2.00 MPa or less. [3] The semiconductor processing adhesive sheet according to [1] or [2], wherein the storage modulus G'(y) is 10.0 MPa or more. [4] The semiconductor processing adhesive sheet according to any one of [1] to [3], wherein the intermediate layer (X) is formed from an intermediate layer forming composition comprising an acrylic polymer (A) and an acrylic polymer (B), and the weight-average molecular weight of the acrylic polymer (A) is greater than the weight-average molecular weight of the acrylic polymer (B). [5] The semiconductor processing adhesive sheet according to [4], wherein the weight-average molecular weight of the acrylic polymer (B) is greater than 250,000. [6] The semiconductor processing adhesive sheet according to [4] or [5], wherein the weight-average molecular weight of the acrylic polymer (A) is greater than 450,000. [7] The semiconductor processing adhesive sheet according to any one of [4] to [6], wherein the acrylic polymer (A) is a non-energy ray curable acrylic polymer and the acrylic polymer (B) is an energy ray curable acrylic polymer. [8] An acrylic copolymer (A1) in which the acrylic polymer (A) has constituent units derived from alkyl (meth)acrylate (a1) and constituent units derived from functional group-containing monomer (a2), wherein the alkyl (meth)acrylate (a1) contains 2-ethylhexyl (meth)acrylate, as described in any one of [4] to [7] above, for use as an adhesive sheet for semiconductor processing. [9] The semiconductor processing adhesive sheet according to [8], wherein the content of constituent units derived from functional group-containing monomers (a2) in the acrylic polymer (A1) is 3 to 11% by mass of the total constituent units (100% by mass) of the acrylic polymer (A1).

[10] The semiconductor processing adhesive sheet according to any one of [4] to [9], wherein the content of acrylic polymer (B) in the intermediate layer forming composition is 30 parts by mass or more per 100 parts by mass of acrylic polymer (A).

[11] The semiconductor processing adhesive sheet according to any one of [1] to

[10] , wherein the tensile modulus of the substrate is 50 MPa or more.

[12] A semiconductor processing adhesive sheet according to any one of [1] to

[11] , used for processing a semiconductor device, wherein the semiconductor device has a surface having one or more protrusions, and the adhesive layer (Y) is attached to the surface of the semiconductor device having one or more protrusions.

[13] A method for manufacturing a semiconductor device, which includes a step of processing a semiconductor device having a surface having one or more protrusions, A method for manufacturing a semiconductor device, comprising processing the semiconductor device while the adhesive layer (Y) of the semiconductor processing adhesive sheet described in any one of [1] to

[11] is attached to a surface of the semiconductor device having one or more protrusions. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a novel adhesive sheet for semiconductor processing that can suppress delamination occurring between an intermediate layer and an adhesive layer when peeling from an adherend such as a semiconductor device.

Embodiment for Carrying out the Invention

[0009] Hereinafter, the present invention will be described in detail using embodiments. In this specification, the "solid content" refers to the components contained in the target composition excluding diluting solvents such as water and organic solvents. In this specification, for preferable numerical ranges (for example, ranges such as content), the lower limit value and the upper limit value described stepwise can be combined independently. For example, from the description "preferably 10 to 90, more preferably 30 to 60", it is also possible to combine the "preferred lower limit value (10)" and the "more preferred upper limit value (60)" to obtain "10 to 60". Similarly, from the description "preferably 10 or more, more preferably 30 or more" and "preferably 90 or less, more preferably 60 or less" for the same matter, it is also possible to combine the "preferred lower limit value (10)" and the "more preferred upper limit value (60)" to obtain "10 or more and 60 or less". In addition, in this specification, "(meth)acrylic" is used as a term meaning one or both of "acrylic" or "methacrylic". Similarly, "(meth)acrylate" is used as a term meaning one or both of "acrylate" or "methacrylate". Similarly, "(meth)acryloyl" is used as a term meaning one or both of "acryloyl" or "methacryloyl". In addition, in the descriptions in this specification, for example, the term "energy ray" means known energy rays such as γ-rays, electron beams, ultraviolet rays, visible light, etc. In this specification, "weight-average molecular weight (Mw)" is a value on a standard polystyrene basis measured by gel permeation chromatography (GPC), specifically a value measured according to the method described in the Examples.

[0010] [Adhesive sheets for semiconductor processing] The semiconductor processing adhesive sheet of the present invention (hereinafter also referred to as "adhesive sheet") comprises a substrate, an energy ray curable intermediate layer (X), and an adhesive layer (Y) in this order, and satisfies the following requirement (1). Requirement (1): Illuminance 230mW / cm 2 , light intensity 380mJ / cm 2 Using the storage modulus G'(x) (unit: MPa) of the intermediate layer (X) at 23°C after irradiation with ultraviolet light under the specified conditions, and the storage modulus G'(y) (unit: MPa) of the adhesive layer (Y) at 23°C, the Q value (unit: MPa) calculated by the following formula (1) is between -30 and 30. Q = {G'(y) - (G'(x) × 40)} ... Equation (1)

[0011] The adhesive sheet, by satisfying requirement (1), exhibits excellent adhesion between the intermediate layer (X) (hereinafter also referred to as "layer (X)") and the adhesive layer (Y) (hereinafter also referred to as "layer (Y)"). If the Q value calculated according to requirement (1) does not meet the range of -30 or more and 30 or less, it is considered that the adhesion between layer (X) and layer (Y) will decrease because layer (X) and layer (Y) have poor wettability to each other's surfaces at the interface between layer (X) and layer (Y). Therefore, the Q value calculated according to requirement (1) is preferably -20 MPa or higher, more preferably -15 MPa or higher, even more preferably -10 MPa or higher, even more preferably -5 MPa or higher, even more preferably -1 MPa or higher, and preferably 25 MPa or lower, more preferably 20 MPa or lower, even more preferably 15 MPa or lower, even more preferably 10 MPa or lower, even more preferably 5 MPa or lower, and even more preferably 1 MPa or lower. The illuminance of 230 mW / cm² is used to calculate the Q value calculated according to requirement (1). 2 , light intensity 380mJ / cm 2 The storage modulus G'(x) (hereinafter also referred to as "modulus G'(x)") of the intermediate layer (X) at 23°C after irradiation with ultraviolet light under the following conditions, and the illuminance of 230 mW / cm². 2 , light intensity 380mJ / cm 2 The storage modulus G'(y) (hereinafter also referred to as "modulus G'(y)") of the intermediate layer (X) at 23°C after irradiation with ultraviolet light under the conditions described above is, more specifically, a value measured based on the method described in the examples below.

[0012] One embodiment of the structure of the adhesive sheet, as described above, comprises a base material, an energy ray curable intermediate layer (X), and an adhesive layer (Y) in that order. That is, it comprises a base material, an intermediate layer (X) provided on one surface of the base material, and an adhesive layer (Y) further provided on the surface of the intermediate layer (X) opposite to the base material. Furthermore, in one embodiment of the configuration of the adhesive sheet, for example, the base material, the intermediate layer (X), and the adhesive layer (Y) may be directly laminated in this order. Here, "direct lamination" refers to a configuration in which, for example, there are no other layers between the base material, layer (X), and layer (Y), and each layer is in direct contact with the others. Furthermore, the adhesive sheet has a configuration in which at least layer (X) and layer (Y) are directly laminated together. Furthermore, in one embodiment of the configuration of the adhesive sheet, a release agent may be provided on the surface of layer (Y) opposite to layer (X). The release agent protects layer (Y) and is removed from layer (Y) when the adhesive sheet is attached to the object. Furthermore, one embodiment of the structure of the adhesive sheet may include layers other than those described above. For example, in order to improve the adhesion between the substrate and the intermediate layer (X), a primer layer made of various curable resins or the like may be provided on one surface of the substrate. Also, in order to prevent the adhesive sheet from becoming statically charged, an antistatic layer containing a known antistatic agent may be provided on one surface of the substrate.

[0013] The thickness of the adhesive sheet is preferably 50 μm or more, more preferably 150 μm or more, and preferably 900 μm or less, more preferably 500 μm or less. In this specification, "thickness of the adhesive sheet" means the thickness of the adhesive sheet excluding the release agent, in the case where the adhesive sheet is provided with a release agent as described later. The thickness of the adhesive sheet can be measured, for example, using the method described in the examples below. Alternatively, it can be calculated as the sum of the thicknesses of each layer described below. Furthermore, the thickness of each layer, as described later, can be measured, for example, using the method described in the examples described later. The following provides a more detailed explanation of each layer that makes up the adhesive sheet.

[0014] <Middle layer (X)> The intermediate layer (X) is an energy-ray curable layer provided between the substrate and the adhesive layer (Y). The intermediate layer (X) may be formed directly on the substrate, but as described above, if other layers such as a primer layer or an antistatic layer are provided on the substrate, it may be formed on top of those other layers. From the viewpoint of further improving adhesion with the adhesive layer (Y), the elastic modulus G'(x) of layer (X) is preferably 0.100 MPa or more, more preferably 0.250 MPa or more, even more preferably 0.450 MPa or more, even more preferably 0.500 MPa or more, and preferably 2.00 MPa or less, more preferably 1.80 MPa or less, even more preferably 1.50 MPa or less, and even more preferably 1.10 MPa or less. Furthermore, the elastic modulus G'(x) of layer (X) is a value measured based on the method described in the examples below.

[0015] The elastic modulus G'(x) of layer (X) can be adjusted, for example, by the amount of acrylic polymer (A) and acrylic polymer (B) blended, the type and content of monomers constituting each acrylic polymer, and the molecular weight of each acrylic polymer, when the intermediate layer forming composition that forms layer (X) contains acrylic polymer (A) and acrylic polymer (B) described later. For example, if acrylic polymer (B1), described later, is used as acrylic polymer (B), the elastic modulus G'(x) can be adjusted by the amount of energy-ray polymerizable groups introduced into acrylic polymer (B1) (the value of α described later). More specifically, increasing the amount of energy-ray polymerizable groups in acrylic polymer (B1) tends to increase the elastic modulus G'(x). Also, increasing the amount of energy-ray polymerizable polymers in the intermediate layer forming composition tends to increase the elastic modulus G'(x). Furthermore, the elastic modulus G'(x) can also be appropriately adjusted by the amount of crosslinking agent and photopolymerization initiator blended into the intermediate layer forming composition.

[0016] Layer (X) is a layer formed from an intermediate layer-forming composition containing acrylic polymer (A) and acrylic polymer (B), wherein the weight-average molecular weight of acrylic polymer (A) is preferably greater than the weight-average molecular weight of acrylic polymer (B). The following describes each component included in a suitable intermediate layer-forming composition for forming layer (X).

[0017] (Acrylic polymer (A)) Acrylic polymer (A) (hereinafter also referred to as "component (A)") is a polymer having constituent units derived from (meth)acrylate, and has a relatively large weight-average molecular weight compared to acrylic polymer (B) (hereinafter also referred to as "component (B)"), which will be described later. The weight-average molecular weight of component (A) is preferably greater than 450,000, more preferably greater than 500,000, and even more preferably greater than 550,000, from the viewpoint of easily maintaining the shape of the intermediate layer, and is preferably 1,500,000 or less, more preferably 1,200,000 or less, and even more preferably 900,000 or less, from the viewpoint of good compatibility with component (B).

[0018] Component (A) is preferably a non-energy ray curable acrylic polymer, from the viewpoint of easily adjusting the elastic modulus G'(x) of layer (X) to the aforementioned preferred range. Component (A) preferably contains an acrylic copolymer (A1) (hereinafter also referred to as "component (A1)") having structural units derived from alkyl (meth)acrylate (a1) and structural units derived from functional group-containing monomer (a2), and more preferably consists of this acrylic copolymer (A1). The copolymerization form of component (A1) is not particularly limited and may be a block copolymer or a random copolymer.

[0019] As alkyl(meth)acrylate(a1) (hereinafter also referred to as "monomer(a1)"), alkyl(meth)acrylates having 1 to 18 carbon atoms in the alkyl group are preferably used. Specifically, examples include methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, n-butyl(meth)acrylate, n-pentyl(meth)acrylate, n-hexyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, isooctyl(meth)acrylate, n-decyl(meth)acrylate, n-dodecyl(meth)acrylate, n-tridecyl(meth)acrylate, myristyl(meth)acrylate, palmityl(meth)acrylate, stearyl(meth)acrylate, and the like. Monomer (a1) may be used alone or in combination of two or more types.

[0020] Among the monomers described above, monomer (a1) preferably contains alkyl (meth)acrylates with 1 to 8 carbon atoms in the alkyl group, and more preferably contains alkyl (meth)acrylates with 4 to 8 carbon atoms in the alkyl group (hereinafter also referred to as "monomer (Y)"). Specifically, monomer (Y) preferably consists of one or more selected from 2-ethylhexyl (meth)acrylate and n-butyl (meth)acrylate, and more preferably 2-ethylhexyl (meth)acrylate. Here, all of the monomer (a1) constituting component (A1) may be monomer (Y), or some may be monomer (Y). The content of monomer (Y) in monomer (a1) is preferably 75 to 100% by mass, more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass, and even more preferably 95 to 100% by mass, based on the total amount of monomer (a1) (100% by mass).

[0021] In component (A1), the content of constituent units derived from monomer (a1) is preferably 50 to 99.5% by mass, more preferably 60 to 99% by mass, even more preferably 60 to 95% by mass, and even more preferably 60 to 92% by mass, relative to the total constituent units (100% by mass) of component (A1). If the content of the constituent units derived from monomer (a1) is 50% by mass or more, it is preferable because it enhances the holding performance of the adhesive sheet, making it easier to improve, for example, its ability to conform to adherends with large differences in surface irregularities. Furthermore, if the content of the constituent units derived from monomer (a1) is 99.5% by mass or less, it is preferable because it ensures a certain amount or more of the constituent units derived from the functional group-containing monomer (a2). Furthermore, when 2-ethylhexyl (meth)acrylate is used as monomer (a1), from the viewpoint of making it easier to adjust the elastic modulus G'(x) of layer (X) to the aforementioned preferred range, the content of constituent units derived from monomer (a1) in component (A1) is preferably 61% by mass or more, more preferably 62% by mass or more, and preferably 68% by mass or less, more preferably 67% by mass or less, even more preferably 66% by mass or less, and even more preferably 65% ​​by mass or less, based on the total constituent units (100% by mass) of component (A1). In this specification, the content of monomer constituent units relative to all constituent units of the polymer (100% by mass) may also be considered as the content of the monomer in 100% by mass of the total amount of monomer blended when synthesizing the polymer. Furthermore, the total constituent units of the polymer (100% by mass) shall not include, for example, the polymerization initiator and chain transfer agent used in the polymerization of the polymer, or constituent units derived from components other than monomers that form the main chain skeleton of the polymer, such as polymerizable compounds (Zb) and (Zc) having energy-ray polymerizable groups, as described later.

[0022] A functional group-containing monomer (a2) (hereinafter also referred to as "monomer (a2)") is a monomer having a functional group such as a hydroxyl group, carboxyl group, epoxy group, amino group, cyano group, nitrogen atom-containing ring group, or alkoxysilyl group. Among the above, one or more monomers selected from hydroxyl group-containing monomers, carboxyl group-containing monomers, and epoxy group-containing monomers are preferred as monomer (a2).

[0023] Examples of monomers containing a hydroxyl group include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; and unsaturated alcohols such as vinyl alcohol and allyl alcohol. Examples of monomers containing a carboxyl group include (meth)acrylic acid, maleic acid, fumaric acid, and itaconic acid. Examples of epoxy-containing monomers include epoxy-group-containing (meth)acrylic acid esters and non-acrylic epoxy-group-containing monomers. Examples of epoxy-group-containing (meth)acrylic acid esters include glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, (3,4-epoxycyclohexyl)methyl (meth)acrylate, and 3-epoxycyclo-2-hydroxypropyl (meth)acrylate. Examples of non-acrylic epoxy-group-containing monomers include glycidyl crotonate and allyl glycidyl ether. Monomer (a2) may be used alone or in combination of two or more types.

[0024] Among monomers (a2), carboxyl group-containing monomers are more preferred, (meth)acrylic acid is even more preferred, and acrylic acid is even more preferred. When a carboxyl group-containing monomer is used as monomer (a2), the cohesive force of the intermediate layer is increased, making it easier to further improve the retention performance of the intermediate layer.

[0025] In component (A1), the content of constituent units derived from monomer (a2) is preferably 0.5 to 40% by mass, more preferably 1 to 30% by mass, even more preferably 3 to 20% by mass, and even more preferably 3 to 15% by mass, relative to the total constituent units (100% by mass) of component (A1). If the content of constituent units derived from monomer (a2) is 0.5% by mass or more, the cohesive force of the intermediate layer increases, and the compatibility with component (B) tends to improve, which is preferable. On the other hand, if the content of constituent units derived from monomer (a2) is 40% by mass or less, it is preferable because a certain amount or more of constituent units derived from monomer (a1) can be secured. Furthermore, from the viewpoint of making it easier to adjust the elastic modulus G'(x) of layer (X) to the aforementioned preferred range, the content of constituent units derived from monomer (a2) in component (A1) is preferably 3% by mass or more, more preferably 5% by mass or more, even more preferably 7% by mass or more, and preferably 11% by mass or less, and more preferably 10% by mass or less, based on the total constituent units (100% by mass) of component (A1).

[0026] Component (A1) may be a copolymer consisting only of constituent units derived from monomer (a1) and monomer (a2) (excluding constituent units derived from components other than monomers, such as polymerization initiators and chain transfer agents). However, it may also be a copolymer that further includes constituent units derived from monomer (a1) and monomer (a2), as well as other monomers (a3) ​​other than monomers (a1) and (a2) (hereinafter also referred to as "monomer (a3)"), and it is preferable that the copolymer includes constituent units derived from monomer (a3).

[0027] Examples of monomers (a3) ​​include cyclic (meth)acrylates such as cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate, as well as vinyl acetate and styrene. Monomer (a3) ​​may be used alone or in combination of two or more types. Among the monomers (a3), vinyl acetate is preferred from the viewpoint of good compatibility with component (B).

[0028] When component (A) contains constituent units derived from monomer (a3), the content of constituent units derived from monomer (a3) ​​in component (A1) is preferably 1 to 45% by mass, more preferably 5 to 45% by mass, even more preferably 10 to 40% by mass, even more preferably 15 to 35% by mass, and even more preferably 20 to 30% by mass, relative to the total constituent units (100% by mass) of the acrylic copolymer (A1).

[0029] In the intermediate layer forming composition, the content of component (A) is preferably 50% by mass or more, more preferably 55% by mass or more, even more preferably 60% by mass or more, and preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less, based on the total amount (100% by mass) of the intermediate layer forming composition. Furthermore, when the intermediate layer forming composition is diluted with a diluent such as an organic solvent, as described later, the total amount of the intermediate layer forming composition refers to the total amount of solids excluding the diluent. The same applies to the adhesive composition described later.

[0030] (Acrylic polymer (B)) Acrylic polymer (B) is a polymer having constituent units derived from (meth)acrylate and has a relatively smaller weight-average molecular weight than acrylic polymer (A). The weight-average molecular weight of component (B) is preferably 50,000 or more, more preferably 100,000 or more, even more preferably 200,000 or more, even more preferably more than 250,000, even more preferably 300,000 or more, and preferably 800,000 or less, more preferably 600,000 or less, even more preferably 550,000 or less, even more preferably 500,000 or less, and even more preferably 450,000 or less, from the viewpoint of easily adjusting the elastic modulus G'(x) of layer (X) to the aforementioned preferred range.

[0031] Component (B) is preferably an energy-ray curable acrylic polymer, from the viewpoint of easily adjusting the elastic modulus G'(x) of layer (X) to the aforementioned preferred range. The energy-ray curable component (B) is an acrylic polymer into which an energy-ray polymerizable group is introduced and which has constituent units derived from (meth)acrylate. The energy-ray polymerizable group is preferably introduced into the side chain of the acrylic polymer. The energy-ray polymerizable group can be any group containing an energy-ray polymerizable carbon-carbon double bond, such as a (meth)acryloyl group or a vinyl group, but the (meth)acryloyl group is preferred.

[0032] Component (B) preferably contains an acrylic copolymer (B1) (hereinafter also referred to as "component (B1)") which is a reaction product obtained by reacting an acrylic copolymer (B0) (hereinafter also referred to as "component (B0)") having structural units derived from alkyl (meth)acrylate (b1) and structural units derived from functional group-containing monomer (b2) with a polymerizable compound (Zb) having an energy-ray polymerizable group, and more preferably consists of component (B1). The copolymerization form of component (B0) is not particularly limited and may be a block copolymer, a random copolymer, or any other form. The content of component (B1) is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass, and even more preferably 100% by mass, relative to the total amount (100% by mass) of component (B) contained in the intermediate layer forming composition.

[0033] Alkyl (meth)acrylate (b1) (hereinafter also referred to as "monomer (b1)") used is an alkyl (meth)acrylate having 1 to 18 carbon atoms in the alkyl group, and a specific example is the one exemplified as monomer (a1). These may be used individually or in combination of two or more types. In component (B0), the content of constituent units derived from monomer (b1) is preferably 50 to 95% by mass, more preferably 55 to 90% by mass, even more preferably 60 to 85% by mass, and even more preferably 65 to 80% by mass, relative to the total constituent units (100% by mass) of component (B0). If the content of the constituent units derived from the monomer (b1) is 50% by mass or more, the shape of the formed intermediate layer (X) can be sufficiently maintained. Furthermore, if the content of the constituent units derived from the monomer (b1) is 95% by mass or less, a certain amount of constituent units derived from the functional group-containing monomer (b2), which serve as reaction sites with the polymerizable compound (Zb), can be secured.

[0034] Furthermore, monomer (b1), like monomer (a1), is preferably an alkyl (meth)acrylate with 1 to 8 carbon atoms in the alkyl group, and more preferably contains monomer (Y) (i.e., an alkyl (meth)acrylate with 4 to 8 carbon atoms in the alkyl group). A preferred compound for monomer (Y) is n-butyl (meth)acrylate, and more preferably n-butyl acrylate. Here, all of the monomer (b1) contained in component (B0) may be monomer (Y), but it is preferable that a portion of it be monomer (Y). The amount of monomer (Y) in monomer (b1) is preferably 65 to 100% by mass, more preferably 70 to 100% by mass, and even more preferably 80 to 95% by mass, of the total amount of monomer (b1) (100% by mass). In one embodiment of the present invention, the monomer (b1) preferably contains one or more selected from methyl (meth)acrylate and n-butyl (meth)acrylate, more preferably contains methyl (meth)acrylate and n-butyl (meth)acrylate, and even more preferably contains methyl methacrylate and n-butyl acrylate.

[0035] Functional group-containing monomer (b2) (hereinafter also referred to as "monomer (b2)") includes monomers having the functional groups exemplified in monomer (a2), and preferably one or more selected from hydroxyl group-containing monomers, carboxyl group-containing monomers, and epoxy group-containing monomers. Specific examples of these compounds are the same as those exemplified as monomer (a2). Furthermore, as monomer (b2), a monomer containing a hydroxyl group is preferred, and among these, various hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate are more preferred, 2-hydroxyethyl (meth)acrylate is even more preferred, and 2-hydroxyethyl acrylate is even more preferred. By using hydroxyalkyl (meth)acrylate, it becomes possible to react the polymerizable compound (Zb) with component (B0) relatively easily.

[0036] Furthermore, the functional groups in monomer (a2) used in component (A) and monomer (b2) used in component (B) may be the same or different, but it is preferable that they be different. That is, for example, if monomer (a2) is a carboxyl group-containing monomer, it is preferable that monomer (b2) is a hydroxyl group-containing monomer. When the functional groups of each are different in this way, it becomes possible to preferentially crosslink component (B) with a crosslinking agent described later, for example, which makes it easier to improve the holding performance of the adhesive sheet described above.

[0037] In component (B0), the content of constituent units derived from monomer (b2) is preferably 5 to 50% by mass, more preferably 10 to 45% by mass, even more preferably 15 to 40% by mass, and even more preferably 20 to 35% by mass, relative to the total constituent units (100% by mass) of component (B0). If the content of constituent units derived from monomer (b2) is 5% by mass or more, a relatively large number of reaction sites with the polymerizable compound (Zb) can be secured, making it easier to introduce energetically polymerizable groups into the side chains. Furthermore, if the content of constituent units derived from monomer (b2) is 50% by mass or less, the shape of the formed intermediate layer (X) can be sufficiently maintained.

[0038] Component (B0) may be a copolymer consisting only of constituent units derived from monomer (b1) and monomer (b2) (excluding constituent units derived from components other than monomers, such as polymerization initiators and chain transfer agents), or it may be a copolymer that further includes constituent units derived from monomer (b1) and monomer (b2), as well as other monomers (b3) other than monomers (b1) and (b2) (hereinafter also referred to as "monomer (b3)"). Examples of monomer (b3) include those exemplified as monomer (a3) ​​mentioned above. The content of constituent units derived from monomer (b3) in component (B0) is preferably 0 to 30% by mass, more preferably 0 to 20% by mass, even more preferably 0 to 10% by mass, and even more preferably 0 to 5% by mass, relative to the total constituent units (100% by mass) of component (B0).

[0039] A polymerizable compound (Zb) is a compound having an energy-ray polymerizable group and a substituent (hereinafter also referred to as a "reactive substituent") that can react with a functional group in the constituent unit derived from the monomer (b2) of component (B0). As mentioned above, examples of energy-ray polymerizable groups include (meth)acryloyl groups and vinyl groups, with (meth)acryloyl groups being preferred. Furthermore, the polymerizable compound (Zb) is preferably a compound having 1 to 5 energy-ray polymerizable groups per molecule. The reactive substituent in the polymerizable compound (Zb) can be appropriately changed depending on the functional group of the monomer (b2), but examples include isocyanate groups, carboxyl groups, epoxy groups, etc., and an isocyanate group is preferred from the viewpoint of reactivity, etc. If the polymerizable compound (Zb) has an isocyanate group, it can react readily with component (B0), for example, when the functional group of monomer (b2) is a hydroxyl group.

[0040] Specific polymerizable compounds (Zb) include, for example, 2-(meth)acryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, (meth)acryloyl isocyanate, allyl isocyanate, glycidyl (meth)acrylate, and (meth)acrylic acid. These polymerizable compounds (Zb) may be used individually or in combination of two or more. Among these, 2-(meth)acryloyloxyethyl isocyanate is preferred, and 2-methacryloyloxyethyl isocyanate is more preferred, from the viewpoint of having an isocyanate group suitable as the reactive substituent and having an appropriate distance between the main chain and the energy-ray polymerizable group. Component (B1) is obtained by reacting a polymerizable compound (Zb) with a preferably 40 to 98 molar equivalents, more preferably 50 to 95 molar equivalents, even more preferably 60 to 90 molar equivalents, and even more preferably 70 to 85 molar equivalents, of the total amount of functional groups derived from monomer (b2) in component (B0) (100 molar equivalents).

[0041] Further, the value of α calculated from the following formula (2) serves as an index representing the number of energy ray-polymerizable groups possessed by component (B1). In component (B1), the value of α is preferably 5 to 40, more preferably 10 to 35, still more preferably 15 to 30. By using component (B1) having such a value of α in the blending amount described later, it becomes easier to adjust the elastic modulus G'(x) of the intermediate layer (X) to a desired range. Formula (2): α = [P b × [Q b × [R b / 100 (In formula (2), [P b represents the content of the structural unit derived from the functional group-containing monomer (b2) with respect to 100 parts by mass of all the structural units of the acrylic copolymer (B0). [Q b represents the molar equivalent of the polymerizable compound (Zb) with respect to 100 molar equivalents of the functional group derived from the functional group-containing monomer (b2) possessed by the acrylic copolymer (B0). [R b represents the number of energy ray-polymerizable groups possessed by the polymerizable compound (Zb).)

[0042] In the composition for forming the intermediate layer, the content of component (B) is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, still more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and preferably 90 parts by mass or less, more preferably 80 parts by mass or less, still more preferably 70 parts by mass or less, even more preferably 60 parts by mass or less, with respect to 100 parts by mass of component (A).

[0043] (Crosslinking agent) The composition for forming the intermediate layer preferably further contains a crosslinking agent. Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, and metal chelate-based crosslinking agents. These crosslinking agents may be used alone or in combination of two or more. Among these, one or more selected from isocyanate-based crosslinking agents and metal chelate-based crosslinking agents are preferred. The intermediate layer-forming composition is crosslinked by a crosslinking agent, for example, by heating after application. The crosslinking agent content is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 5 parts by mass, even more preferably 0.4 to 3 parts by mass, and even more preferably 0.5 to 1 part by mass, per 100 parts by mass of component (A).

[0044] Examples of isocyanate-based crosslinking agents include polyisocyanate compounds. Specific examples of polyisocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; and alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate. In addition, biuret and isocyanurate compounds of these compounds, as well as adduct compounds resulting from reactions with low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil, can also be used. These may be used individually or in combination of two or more. Among the above, polyhydric alcohol (e.g., trimethylolpropane) adducts of aromatic polyisocyanates such as tolylene diisocyanate are preferred.

[0045] Examples of metal chelating crosslinking agents include chelating compounds of polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium. For example, compounds in which acetylacetone, ethyl acetoethyl, tris(2,4-pentanedione), etc., are coordinated to these polyvalent metals are also included. Among these, aluminum chelating compounds are preferred. These may be used individually or in combination of two or more.

[0046] Examples of epoxy crosslinking agents include 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-m-xylylenediamine, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidylaniline, and diglycidylamine. These may be used individually or in combination of two or more.

[0047] Examples of aziridine-based crosslinking agents include diphenylmethane-4,4'-bis(1-aziridine carboxamide), trimethylolpropane tri-β-aziridinyl propionate, tetramethylolmethane tri-β-aziridinyl propionate, toluene-2,4-bis(1-aziridine carboxamide), triethylene melamine, bisisophthaloyl-1-(2-methylaziridine), tris-1-(2-methylaziridine)phosphine, trimethylolpropane tri-β-(2-methylaziridine)propionate, and hexa[1-(2-methyl)-aziridinyl]triphosphotriazine.

[0048] (Photopolymerization initiator) Preferably, the intermediate layer forming composition further contains a photopolymerization initiator. The inclusion of a photopolymerization initiator facilitates the curing of the intermediate layer forming composition by energy rays such as ultraviolet light. Examples of photopolymerization initiators include benzoin compounds, acetophenone compounds, acyl phosphinoxide compounds, titanocene compounds, thioxanthone compounds, azo compounds, peroxide compounds, and photosensitizers such as amines and quinones. More specifically, for example, acetophenone, 2,2-diethoxybenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, Michler ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl diphenysulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyldimethylketal, dibenzyl, diacetyl, 1-chloroanthraquinone, 2-chloroanthraquinone, 2-ethylanthraquinone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl Examples of low molecular weight polymerization initiators include phenyl ketones, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, diethylthioxanthone, isopropylthioxanthone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, as well as oligomerized polymerization initiators such as oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone}. These may be used alone or in combination of two or more. Among these, 1-hydroxycyclohexylphenyl ketone is preferred.

[0049] The amount of photopolymerization initiator is preferably 0.3 to 15 parts by mass, more preferably 1 to 10 parts by mass, and even more preferably 3 to 8 parts by mass, per 100 parts by mass of component (A).

[0050] (Other additives) The intermediate layer forming composition may contain other additives as long as they do not impair the effects of the present invention. Examples of other additives include antioxidants, plasticizers, fillers, rust inhibitors, pigments, dyes, tackifiers, and the like. When these additives are included, the content of each additive is preferably 0.01 to 6 parts by mass, more preferably 0.01 to 2 parts by mass, per 100 parts by mass of component (A).

[0051] Furthermore, the intermediate layer forming composition may be further diluted with an organic solvent to form a solution of the intermediate layer forming composition, from the viewpoint of improving the coatability when forming an intermediate layer on the surface of the substrate or release agent. Examples of organic solvents include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, and isopropanol. The organic solvent used may be the same organic solvent used during the synthesis of components (A) and (B), or one or more organic solvents other than those used during synthesis may be added. When the intermediate layer forming composition is in the form of a solution, the solid content concentration of the solution of the intermediate layer forming composition is preferably 5 to 70% by mass, more preferably 10 to 60% by mass, and even more preferably 15 to 50% by mass.

[0052] Furthermore, layer (X) may be a single layer or may be formed from multiple layers. Furthermore, the thickness of layer (X) can be appropriately selected depending on the semiconductor device to be adhered to. For example, when attaching to a wafer surface on which bumps are formed, the thickness can be appropriately selected depending on the height of the bumps on the semiconductor wafer to be adhered to. The thickness of the intermediate layer in one embodiment of the adhesive sheet is, for example, preferably 10 to 800 μm, more preferably 20 to 600 μm, even more preferably 40 to 400 μm, even more preferably 60 to 250 μm, and even more preferably 80 to 200 μm. Here, the thickness of layer (X) refers to the total thickness of the entire layer (X). For example, the thickness of a layer (X) consisting of multiple layers refers to the total thickness of all the layers that make up the layer (X).

[0053] <Adhesive layer (Y)> The adhesive layer (Y) is formed on top of the intermediate layer (X), and the adhesive sheet is attached to the substrate by layer (Y). Layer (Y) is usually laminated directly on top of layer (X). Furthermore, from the viewpoint of making the adhesive sheet more easily conform to the unevenness of the adherend surface, the elastic modulus G'(y) of layer (Y) is preferably 10.0 MPa or more, more preferably 20.0 MPa or more, even more preferably 30.0 MPa or more, even more preferably 35.0 MPa or more, and preferably 80.0 MPa or less, more preferably 70.0 MPa or less, even more preferably 60.0 MPa or less, and even more preferably 50.0 MPa or less. Furthermore, the elastic modulus G'(y) of layer (Y) is a value measured based on the method described in the examples below.

[0054] The elastic modulus G'(y) of layer (Y) can be adjusted, for example, by selecting the components and their content in the adhesive composition forming layer (Y). For example, if the adhesive composition contains an acrylic polymer (C) described later as an adhesive resin, the elastic modulus G'(y) can be adjusted by the amount of acrylic polymer (C) blended, the types and content of monomers constituting the acrylic polymer (C), and the molecular weight of the acrylic polymer (C). For example, if an acrylic polymer (C1) described later is used as the acrylic polymer (C), the elastic modulus G'(y) can be adjusted by the amount of energy-ray polymerizable groups introduced into the acrylic polymer (C1) (the value of β described later). More specifically, increasing the amount of energy-ray polymerizable groups tends to increase the elastic modulus G'(y). Also, increasing the amount of polymers with energy-ray polymerizability in the adhesive resin tends to increase the elastic modulus G'(y). Furthermore, the elastic modulus G'(y) can be appropriately adjusted by the amount of crosslinking agent and photopolymerization initiator blended into the adhesive composition.

[0055] The adhesive composition that forms the adhesive layer contains, for example, an acrylic polymer, polyurethane, rubber polymer, polyolefin, silicone, etc., as an adhesive component (adhesive resin) capable of exhibiting tackiness in the adhesive layer. Among these, acrylic polymers are preferred. Furthermore, it is preferable that layer (Y) is an energy-ray curable layer. When layer (Y) is energy-ray curable, it has high adhesive strength that can sufficiently hold the adherend before energy-ray irradiation, while after energy-ray irradiation, the adhesive strength is reduced by curing layer (Y), making it possible to create an adhesive sheet that can be easily peeled off the adherend, such as a wafer.

[0056] The adhesive composition forming the adhesive layer may have energy ray curability by incorporating an energy ray curable compound separately from the adhesive resin, but it is preferable that the adhesive resin itself has energy ray curability. When the adhesive resin itself has energy ray curability, energy ray polymerizable groups are introduced into the adhesive resin, and it is preferable that the energy ray polymerizable groups are introduced into the main chain or side chains of the adhesive resin.

[0057] Furthermore, when an energy-ray curable compound is added separately from the adhesive resin, the energy-ray curable compound used is a monomer or oligomer having an energy-ray polymerizable group. The oligomer is an oligomer with a weight-average molecular weight (Mw) of less than 10,000, and examples include urethane (meth)acrylate. Even if the adhesive resin itself is energy-ray curable, the adhesive composition may also contain energy-ray curable compounds other than the adhesive resin.

[0058] The following describes in more detail the case where the adhesive resin contained in the adhesive composition is an energy-ray curable acrylic polymer (C) (hereinafter also referred to as "component (C)"). Specifically, each component contained in a suitable adhesive composition that forms an energy-ray curable layer (Y), which is a preferred embodiment of the layer (Y) used in this embodiment, will be described.

[0059] (Acrylic polymer (C)) Acrylic polymer (C) is an acrylic polymer into which energy-ray polymerizable groups are introduced and which has constituent units derived from (meth)acrylate. It is preferable that the energy-ray polymerizable groups are introduced into the side chains of the acrylic polymer. The acrylic polymer (C) preferably contains an acrylic copolymer (C1) (hereinafter also referred to as "component (C1)") which is a reaction product obtained by reacting an acrylic copolymer (C0) (hereinafter also referred to as "component (C0)") having constituent units derived from alkyl (meth)acrylate (c1) and constituent units derived from functional group-containing monomer (c2) with a polymerizable compound (Zc) having an energy-ray polymerizable group, and more preferably consists of component (C1). The copolymerization form of component (C0) is not particularly limited and may be a block copolymer, a random copolymer, or any other form. The content of component (C1) is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass, and even more preferably 100% by mass, based on the total amount (100% by mass) of component (C) contained in the adhesive composition.

[0060] As alkyl (meth)acrylate (c1) (hereinafter also referred to as "monomer (c1)"), alkyl (meth)acrylates having 1 to 18 carbon atoms in the alkyl group are used. Specific examples include those exemplified as monomer (a1), and these may be used individually or in combination of two or more. From the viewpoint of improving the adhesive strength of the formed adhesive layer, the content of constituent units derived from monomer (c1) in component (C0) is preferably 50 to 99% by mass, more preferably 60 to 98% by mass, even more preferably 70 to 97% by mass, and even more preferably 75 to 96% by mass, relative to the total constituent units (100% by mass) of component (C0).

[0061] Furthermore, monomer (c1), like monomer (a1) and monomer (b1), preferably contains an alkyl (meth)acrylate with 1 to 8 carbon atoms in the alkyl group, and more preferably contains an alkyl (meth)acrylate with 4 to 8 carbon atoms in the alkyl group (i.e., monomer (Y)). The monomer (Y) constituting component (C1) is preferably one or more selected from 2-ethylhexyl (meth)acrylate and n-butyl (meth)acrylate, with 2-ethylhexyl (meth)acrylate being more preferred. Here, all of the monomer (c1) constituting component (C1) may be monomer (Y), or some may be monomer (Y). The content of monomer (Y) in monomer (c1) is preferably 75 to 100% by mass, more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass, and even more preferably 95 to 100% by mass, based on the total amount of monomer (c1) (100% by mass).

[0062] Functional group-containing monomer (c2) (hereinafter also referred to as "monomer (c2)") includes monomers having the functional groups exemplified as functional group-containing monomer (a2) above, and specifically, one or more selected from hydroxyl group-containing monomers, carboxyl group-containing monomers, and epoxy group-containing monomers are preferred. Specific examples of these compounds are the same as those exemplified as monomer (a2). Furthermore, as the monomer (c2), a monomer containing a hydroxyl group is preferred, and among these, various hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate are more preferred, 2-hydroxyethyl (meth)acrylate is even more preferred, and 2-hydroxyethyl acrylate is even more preferred. By using hydroxyalkyl (meth)acrylate, it becomes possible to react the polymerizable compound (Zc) with component (C0) relatively easily.

[0063] The content of constituent units derived from monomer (c2) in component (C0) is preferably 1 to 40% by mass, more preferably 2 to 35% by mass, even more preferably 3 to 30% by mass, and even more preferably 4 to 25% by mass, relative to the total constituent units (100% by mass) of component (C0). If the content of the constituent units derived from the monomer (c2) is 1% by mass or more, a certain amount of functional groups that serve as reaction sites with the polymerizable compound (Zc) can be secured. Therefore, the adhesive layer can be properly cured by energy ray irradiation, making it possible to reduce the adhesive strength after energy ray irradiation. Furthermore, it becomes easier to improve the interlayer strength between the adhesive layer (Y) and the intermediate layer (X) after energy ray irradiation. In addition, if the content of the constituent units derived from the monomer (c2) is 40% by mass or less, a sufficient pot life can be secured when applying the adhesive composition solution to form the adhesive layer.

[0064] Component (C0) may be a copolymer consisting only of constituent units derived from monomer (c1) and monomer (c2) (excluding constituent units derived from components other than monomers, such as polymerization initiators and chain transfer agents), or it may be a copolymer that further includes constituent units derived from monomer (c3) other than monomers (c1) and (c2) (hereinafter also referred to as "monomer (c3)"). Examples of monomer (c3) include those exemplified as monomer (a3) ​​mentioned above. The content of constituent units derived from monomer (c3) in component (C0) is preferably 0 to 30% by mass, more preferably 0 to 20% by mass, even more preferably 0 to 10% by mass, and even more preferably 0 to 5% by mass, relative to the total constituent units (100% by mass) of component (C0).

[0065] The polymerizable compound (Zc), like the polymerizable compound (Zb) described above, is a compound having an energy-ray polymerizable group and a substituent (reactive substituent) that can react with a functional group in the constituent unit derived from the monomer (c2) of component (C0). Preferably, it is a compound having 1 to 5 energy-ray polymerizable groups per molecule. Specific examples of reactive substituents and energy-ray polymerizable groups are the same as those for polymerizable compound (Zb). Therefore, isocyanate groups are preferred as reactive substituents, and (meth)acryloyl groups are preferred as energy-ray polymerizable groups. Furthermore, specific polymerizable compounds (Zc) can be the same as those exemplified as polymerizable compounds (Zb) above, with 2-(meth)acryloyloxyethyl isocyanate being preferred and 2-methacryloyloxyethyl isocyanate being more preferred. Note that polymerizable compounds (Zc) may be used alone or in combination of two or more. Component (C1) is obtained by reacting a polymerizable compound (Zc) with a preferably 40 to 98 molar equivalents, more preferably 50 to 95 molar equivalents, even more preferably 60 to 90 molar equivalents, and even more preferably 70 to 85 molar equivalents, of the total amount of functional groups derived from monomer (c2) in component (C0) (100 molar equivalents).

[0066] Furthermore, the value of β calculated from the following formula (3) is an indicator of the number of energy-ray polymerizable groups in component (C1). In component (C1), the value of β calculated from the following formula (3) is preferably 0.5 to 30, more preferably 1.0 to 25, even more preferably 5 to 20, and even more preferably 10 to 20. By including a component (C1) with such a β value in the adhesive layer, it becomes easier to adjust the elastic modulus G'(y) of the adhesive layer (Y) to a desired range. Equation (3):β=[P c ] × [Q c ] × [R c 〕 / 100 (In formula (3), [P c [Q] indicates the content of constituent units derived from functional group-containing monomers (c2) relative to 100 parts by mass of all constituent units of the acrylic copolymer (C0). c [R] represents the molar equivalent of the polymerizable compound (Zc) relative to 100 molar equivalents of functional groups derived from the functional group-containing monomer (c2) of the acrylic copolymer (C0). c ] indicates the number of energy-ray polymerizable groups in the polymerizable compound (Zc).

[0067] The weight-average molecular weight of component (C) is preferably 100,000 to 1,500,000, more preferably 250,000 to 1,000,000, even more preferably 300,000 to 900,000, and even more preferably 350,000 to 800,000. Having such a weight-average molecular weight makes it possible to impart appropriate tackiness to the adhesive layer.

[0068] The content of component (C) in the adhesive composition is preferably 70 to 99% by mass, more preferably 75 to 98% by mass, and even more preferably 80 to 96% by mass, based on the total amount (100% by mass) of the adhesive composition.

[0069] (Crosslinking agent) Preferably, the adhesive composition further contains a crosslinking agent. The adhesive composition is crosslinked by the crosslinking agent, for example, by heating after application. When component (C) is crosslinked by the crosslinking agent, the adhesive layer forms a proper coating film and is more likely to exhibit its function as an adhesive layer. Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, and chelate-based crosslinking agents, with isocyanate-based crosslinking agents being preferred among these. The crosslinking agent may be used alone or in combination of two or more types. Specific examples of isocyanate-based crosslinking agents include those exemplified as crosslinking agents that can be used in intermediate layer-forming compositions, and the preferred compounds are similar. The crosslinking agent content is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 7 parts by mass, and even more preferably 0.3 to 4 parts by mass, per 100 parts by mass of component (C).

[0070] (Photopolymerization initiator) The adhesive composition preferably further contains a photopolymerization initiator. Examples of photopolymerization initiators include those used as photopolymerization initiators in the aforementioned intermediate layer forming composition. The photopolymerization initiator may be used alone or in combination of two or more. Among the above, 1-hydroxycyclohexylphenyl ketone is preferred. The content of the photopolymerization initiator is preferably 0.3 to 15 parts by mass, more preferably 1 to 10 parts by mass, and even more preferably 3 to 8 parts by mass, per 100 parts by mass of component (C).

[0071] (Other additives) The adhesive composition may contain other additives as long as they do not impair the effects of the present invention. Examples of other additives include tackifiers, antioxidants, plasticizers, fillers, rust inhibitors, pigments, dyes, and the like. When these additives are included, the content of each additive is preferably 0.01 to 6 parts by mass, more preferably 0.01 to 2 parts by mass, per 100 parts by mass of component (C).

[0072] Furthermore, when forming a layer (Y) on the surface of layer (X) or the release agent, the adhesive composition may be further diluted with an organic solvent to form a solution of the adhesive composition, from the viewpoint of improving its applicability. Examples of organic solvents include those exemplified in the description of the intermediate layer-forming composition mentioned above. The organic solvent used may be the same organic solvent used during the synthesis of the adhesive resin component (C), or one or more organic solvents other than those used during the synthesis may be added. When the adhesive composition is in the form of a solution, the solid content concentration of the solution of the adhesive composition is preferably 5 to 70% by mass, more preferably 10 to 60% by mass, and even more preferably 15 to 50% by mass.

[0073] Furthermore, layer (Y) may be a single layer or may be formed from multiple layers. Furthermore, the thickness of layer (Y) can be appropriately selected depending on the semiconductor device to be deposited on, for example, preferably 1 to 100 μm, more preferably 1 to 75 μm, and even more preferably 3 to 50 μm. Here, the thickness of layer (Y) refers to the total thickness of the entire layer (Y). For example, the thickness of a layer (Y) consisting of multiple layers refers to the total thickness of all the layers that make up the layer (Y).

[0074] <Base material> Regarding the substrate, a resin film is preferred from the viewpoint of being able to achieve good retention performance with respect to the adherend. Examples of resin films include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, ethylene-vinyl acetate copolymer (EVA) film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, ethylene-(meth)acrylic acid copolymer film, ethylene-(meth)acrylic acid ester copolymer film, polycarbonate film, polystyrene film, polyphenylene sulfide film, cycloolefin polymer film, polyurethane film, ionomer resin film, polyimide film, fluororesin film, and films formed from energy ray curable resin compositions.

[0075] Among the aforementioned resin films, in order to further improve the adhesion performance, films formed from polyethylene film, polypropylene film, ethylene-vinyl acetate copolymer (EVA) film, polyethylene terephthalate film, or energy ray curable resin composition are preferred, and films formed from energy ray curable resin composition are more preferred. The following describes an energy-ray curable resin composition used for forming a suitable substrate and the components contained in the energy-ray curable resin composition.

[0076] (Energy ray curable resin composition) The energy-ray curable composition that can be used to form the aforementioned suitable substrate can be cured by irradiation with energy rays. The energy-ray curable composition preferably contains, more specifically, a urethane (meth)acrylate (d1) (hereinafter also referred to as "component (d1)") and a polymerizable compound (d3) (hereinafter also referred to as "component (d3)") having an alicyclic, aromatic, or heterocyclic structure, as energy-ray polymerizable compounds. In addition, the energy-ray curable composition may contain, in addition to components (d1) and (d3), a polyfunctional polymerizable compound (d2) (hereinafter also referred to as "component (d2)") and / or a polymerizable compound (d4) (hereinafter also referred to as "component (d4)") having a functional group. Furthermore, the energy-ray curable composition may contain, in addition to the above components, a photopolymerization initiator. Moreover, the energy-ray curable composition may contain other additives and resin components to the extent that they do not impair the effects of the present invention.

[0077] [Urethane (meth)acrylate (d1)] Urethane (meth)acrylate (d1) is a compound having at least a (meth)acryloyl group and a urethane bond, and possessing the property of polymerization curing by energy ray irradiation. Urethane (meth)acrylate (d1) may be an oligomer, a polymer, or a mixture thereof, but it is preferably an oligomer. The weight-average molecular weight of component (d1) is preferably 1,000 to 100,000, more preferably 2,000 to 60,000, and even more preferably 3,000 to 20,000. The number of (meth)acryloyl groups in component (d1) (hereinafter also referred to as "number of functional groups") may be monofunctional, difunctional, or trifunctional or more, but monofunctional or difunctional is preferred.

[0078] Component (d1) can be obtained, for example, by reacting a terminal isocyanate urethane prepolymer, which is obtained by reacting a polyol compound with a polyvalent isocyanate compound, with a (meth)acrylate having a hydroxyl group. Component (d1) may be used alone or in combination of two or more components.

[0079] The polyol compound used as the raw material for component (d1) is not particularly limited as long as it is a compound having two or more hydroxyl groups. It may be a bifunctional diol, a trifunctional triol, or a polyol with four or more functions, but a bifunctional diol is preferred, and a polyester-type diol or a polycarbonate-type diol is more preferred.

[0080] Examples of polyvalent isocyanate compounds include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate, norbornane diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, and ω,ω'-diisocyanate dimethylcyclohexane; and aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tolidine diisocyanate, tetramethylene xylylene diisocyanate, and naphthalene-1,5-diisocyanate. Among these, one or more selected from the group consisting of isophorone diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are preferred, with isophorone diisocyanate being more preferred.

[0081] Component (d1) can be obtained by reacting the aforementioned polyol compound with a polyvalent isocyanate compound to obtain a terminal isocyanate urethane prepolymer, and then reacting the (meth)acrylate having a hydroxyl group with the prepolymer. The (meth)acrylate having a hydroxyl group is not particularly limited as long as it is a compound having at least one molecule containing both a hydroxyl group and a (meth)acryloyl group.

[0082] Specific examples of (meth)acrylates having a hydroxyl group include, for example, hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, 5-hydroxycyclooctyl (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate, polyethylene glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate; hydroxyl group-containing (meth)acrylamides such as N-methylol (meth)acrylamide; and reaction products obtained by reacting vinyl alcohol, vinyl phenol, and diglycidyl esters of bisphenol A with (meth)acrylic acid. Among these, hydroxyalkyl (meth)acrylate is preferred, and 2-hydroxyethyl (meth)acrylate is more preferred.

[0083] The conditions for reacting the terminal isocyanate urethane prepolymer and the (meth)acrylate having a hydroxyl group are preferably such that the reaction is carried out at 60-100°C for 1-4 hours in the presence of a solvent and catalyst, which may be added as needed.

[0084] The content of component (d1) in the energy ray curable composition is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and even more preferably 25 to 55% by mass, of the total amount (100% by mass) of the energy ray curable composition.

[0085] [Polyfunctional polymerizable compound (d2)] A polyfunctional polymerizable compound (d2) is a compound having two or more photopolymerizable unsaturated groups. Photopolymerizable unsaturated groups are functional groups containing a carbon-carbon double bond, such as (meth)acryloyl groups, vinyl groups, allyl groups, and vinylbenzyl groups. Two or more types of photopolymerizable unsaturated groups may be combined. A three-dimensional network structure (crosslinked structure) is formed by the reaction of a photopolymerizable unsaturated group in component (d2) with a (meth)acryloyl group in component (d1), or by the reaction of photopolymerizable unsaturated groups in component (d2) with each other. The number of photopolymerizable unsaturated groups (number of functional groups) in a polyfunctional polymerizable compound is preferably 2 to 10, and more preferably 3 to 6. Furthermore, the weight-average molecular weight of component (d2) is preferably 30 to 40,000, more preferably 100 to 10,000, and even more preferably 200 to 1,000.

[0086] Note that there is some overlap between the definition of component (d2) and the definitions of components (d3) and (d4) described later, but the overlapping portion is included in component (d2). For example, a compound having an alicyclic structure, an aromatic ring structure, or a heterocyclic structure and having two or more (meth)acryloyl groups is included in the definitions of both component (d2) and component (d3), but in this invention, such a compound is included in component (d2). Also, a compound containing a functional group such as a hydroxyl group, an epoxy group, an amide group, or an amino group and having two or more (meth)acryloyl groups is included in the definitions of both component (d2) and component (d4), but in this invention, such a compound is included in component (d2).

[0087] Specific examples of component (d2) include diethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, divinylbenzene, vinyl (meth)acrylate, divinyl adipate, N,N'-methylenebis(meth)acrylamide, etc. Component (d2) may be used alone or in combination of two or more.

[0088] If the energy ray curable composition contains component (d2), the content of component (d2) in the energy ray curable composition is preferably 1 to 40% by mass, more preferably 3 to 20% by mass, and even more preferably 5 to 15% by mass, of the total amount (100% by mass) of the energy ray curable composition.

[0089] [Polymerizable compounds having an alicyclic, aromatic ring, or heterocyclic structure (d3)] Component (d3) is a polymerizable compound having an alicyclic, aromatic, or heterocyclic structure, and more preferably a compound having at least one (meth)acryloyl group, and more preferably a compound having one (meth)acryloyl group. By using component (d3), the film-forming properties of the resulting energy ray-curable composition can be improved. Although there is some overlap between the definition of component (d3) and the definition of component (d4) described later, the overlapping portion is included in component (d4). For example, a compound having at least one (meth)acryloyl group, an alicyclic structure, an aromatic ring structure, or a heterocyclic structure, and a functional group such as a hydroxyl group, an epoxy group, an amide group, or an amino group is included in the definitions of both component (d3) and component (d4), but in this invention, such a compound is included in component (d4).

[0090] As for (meth)acrylates having an alicyclic structure, (meth)acrylates having an alicyclic structure with 6 to 20 ring-forming atoms are preferred, and examples include isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, adamantane (meth)acrylate, and the like. Examples of (meth)acrylates having an aromatic ring structure include phenyl(meth)acrylate; benzyl(meth)acrylate; phenol ethylene oxide-modified acrylates such as phenoxyethyl(meth)acrylate; p-cresol ethylene oxide-modified acrylates such as p-methylphenoxyethyl acrylate; o-cresol ethylene oxide-modified acrylates such as o-methylphenoxyethyl acrylate; p-nonylphenol ethylene oxide-modified acrylate; o-phenylphenol ethylene oxide-modified acrylate; p-cumylphenol ethylene oxide-modified acrylate; and the like. Examples of (meth)acrylates having a heterocyclic structure include tetrahydrofurfuryl(meth)acrylate and morpholin(meth)acrylate. Furthermore, component (d3) may be used alone or in combination of two or more types.

[0091] Component (d3) preferably contains one or more selected from (meth)acrylates having an alicyclic structure and (meth)acrylates having an aromatic ring structure, and more preferably contains both (meth)acrylates having an alicyclic structure and (meth)acrylates having an aromatic ring structure. Among the (meth)acrylates having an alicyclic structure, isobornyl (meth)acrylate is preferred. Among the (meth)acrylates having an aromatic ring structure, p-cresol ethylene oxide modified acrylate is preferred, and p-methylphenoxyethyl acrylate is more preferred.

[0092] The content of component (d3) in the energy ray curable composition is preferably 10 to 90% by mass, more preferably 20 to 85% by mass, even more preferably 30 to 80% by mass, even more preferably 40 to 75% by mass, and even more preferably 50 to 70% by mass, based on the total amount (100% by mass) of the energy ray curable composition.

[0093] [Polymerizable compounds having functional groups (d4)] Component (d4) is a polymerizable compound containing functional groups such as hydroxyl groups, epoxy groups, amide groups, and amino groups, and more preferably a compound having at least one (meth)acryloyl group, and more preferably a compound having one (meth)acryloyl group. Note that "functional group" in component (d4) refers to a functional group located at the end of the molecular structure, and does not include, for example, ether bonds or ester bonds. Furthermore, the functional group in component (d4) does not include a (meth)acryloyl group.

[0094] Examples of component (d4) include hydroxyl group-containing (meth)acrylate, epoxy group-containing compound, amide group-containing compound, and amino group-containing (meth)acrylate. Among these, hydroxyl group-containing (meth)acrylate is preferred. Examples of hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, phenylhydroxypropyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl acrylate. Component (d4) may be used alone or in combination of two or more.

[0095] If the energy ray curable composition contains component (d4), the content of component (d4) in the energy ray curable composition is preferably 1 to 40% by mass, more preferably 7 to 35% by mass, and even more preferably 10 to 30% by mass, of the total amount (100% by mass) of the energy ray curable composition.

[0096] [Polymerizable compounds other than components (d1) to (d4) (d5)] The energy ray curable composition may also contain other polymerizable compounds (d5) other than the components (d1) to (d4) mentioned above, as long as the effects of the present invention are not impaired. Examples of component (d5) include alkyl (meth)acrylates having an alkyl group with 1 to 20 carbon atoms; vinyl compounds such as styrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinylformamide, N-vinylpyrrolidone, and N-vinylcaprolactam. Component (d5) may be used alone or in combination of two or more.

[0097] If the energy ray curable composition contains component (d5), the content of component (d5) in the energy ray curable composition is preferably 1 to 10% by mass, more preferably 1 to 5% by mass, and even more preferably 1 to 2% by mass, based on the total amount (100% by mass) of the energy ray curable composition.

[0098] [Photopolymerization initiator] The energy ray curable composition preferably further contains a photopolymerization initiator, from the viewpoint of shortening the polymerization time by light irradiation and reducing the amount of light irradiation when forming the substrate. Examples of photopolymerization initiators include those exemplified as photopolymerization initiators used in the aforementioned intermediate layer forming compositions. The photopolymerization initiators may be used alone or in combination of two or more. Among those mentioned above, 1-hydroxycyclohexylphenyl ketone is preferred. The amount of photopolymerization initiator in the energy ray curable composition is preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.3 to 5 parts by mass, based on 100 parts by mass of the total amount of components (d1) to (d5).

[0099] [Other additives] The energy ray curable composition may contain other additives, to the extent that they do not impair the effects of the present invention. Examples of other additives include antistatic agents, antioxidants, plasticizers, fillers, rust inhibitors, pigments, dyes, and the like. When these additives are included, the content of each of the other additives in the energy ray curable composition is preferably 0.01 to 6 parts by mass, more preferably 0.1 to 3 parts by mass, based on 100 parts by mass of the total amount of components (d1) to (d5).

[0100] The film formed from the energy ray curable composition is obtained by polymerization curing of the energy ray curable composition having the above composition by energy ray irradiation. In other words, the film formed from the energy ray curable composition is a cured product of the energy ray curable composition. Therefore, it is preferable that the film formed from the energy-ray-curable composition contains polymerization units derived from component (d1) and polymerization units derived from component (d3). Furthermore, the film formed from the energy-ray-curable composition may also contain polymerization units derived from component (d2) and / or component (d4), or it may contain polymerization units derived from component (d5). The content ratio of each polymerization unit in the film formed from the energy-ray-curable composition usually corresponds to the ratio (compounding ratio) of each component constituting the energy-ray-curable composition.

[0101] The substrate may be a resin film having only one of the aforementioned resins, or it may have two or more. For example, it may be a single-layer film made of one resin film, or a multi-layer film made by laminating multiple resin films. Furthermore, the resin film may contain known fillers, colorants, antistatic agents, antioxidants, organic lubricants, catalysts, etc. Also, the resin film may be transparent or colored as desired. Furthermore, surface treatments such as sputtering, corona discharge, flame irradiation, ultraviolet irradiation, electron beam irradiation, oxidation, etching, or priming may be applied to at least one surface of the substrate as needed. The thickness of the substrate is preferably 10 to 500 μm, more preferably 15 to 300 μm, and even more preferably 20 to 200 μm. Here, "substrate thickness" refers to the total thickness of the substrate. For example, when using a multilayer film consisting of two or more layers as described above, the substrate thickness refers to the total thickness of all the layers that make up the substrate.

[0102] Furthermore, from the viewpoint of excellent handling of the adhesive sheet, the tensile modulus of the substrate used in this embodiment is preferably 50 MPa or more, more preferably 100 MPa or more, even more preferably 150 MPa or more, and preferably 3,000 MPa or less, more preferably 1,500 MPa or less, and even more preferably 500 MPa or less. Furthermore, the tensile modulus of the substrate is a value measured based on the method described in the examples below.

[0103] <Release agent> The adhesive sheet may further have a release agent on the surface of the adhesive layer (Y) opposite to layer (X). Examples of release agents include release sheets that have been treated on both sides and release sheets that have been treated on one side. These release sheets are made by coating a release agent onto a release agent substrate. Examples of substrates for release agents include resin films used as substrates as described above, and polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene are preferred. Examples of release agents include rubber elastomers such as isoprene resins and butadiene resins, silicone resins, olefin resins, long-chain alkyl resins, alkyd resins, and fluororesins. There are no particular restrictions on the thickness of the release agent, but it is preferably 10 to 200 μm, and more preferably 20 to 150 μm.

[0104] [Method for manufacturing adhesive sheets for semiconductor processing] The method for manufacturing the semiconductor processing adhesive sheet of the present invention is not particularly limited, as long as it is possible to manufacture an adhesive sheet having a substrate, an intermediate layer (X), and an adhesive layer (Y) in that order, and can be manufactured by known methods. For example, it can be manufactured by preparing a substrate with an intermediate layer (X) on one side of the substrate, and then laminating an adhesive layer (Y) on top of the intermediate layer (X) of the substrate with the intermediate layer. A substrate with an intermediate layer can be prepared, for example, by applying an intermediate layer-forming composition or a solution thereof to one side of the substrate, and then heating and drying it to form an intermediate layer (X). Alternatively, an intermediate layer-forming composition or a solution thereof may be applied to the release treatment surface of a release agent, and then heated and dried to form an intermediate layer (X) on the release agent, and this layer (X) may be bonded to the substrate to obtain a substrate with an intermediate layer. The release agent should be removed before laminating the adhesive layer (Y) onto the intermediate layer (X).

[0105] The adhesive layer (Y) can be formed by applying an adhesive composition or a solution thereof to the release surface of a release agent different from the one used to prepare the intermediate layer (X), heating and drying it, and then bonding the adhesive layer (Y) with the release agent attached onto the intermediate layer (X). The release agent may be peeled off from the adhesive layer (Y) or used as a release agent provided on the adhesive layer (Y) as is. Alternatively, the adhesive layer (Y) may be formed by directly applying the adhesive composition onto the intermediate layer (X) of the substrate with the intermediate layer, and then heating and drying it. In this case, a release agent may be further bonded onto the adhesive layer (Y).

[0106] Methods for applying the intermediate layer-forming composition, adhesive composition, or solution thereof onto a substrate or release agent include, for example, spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating. Furthermore, when forming a relatively thick intermediate layer (X), a solution of the intermediate layer forming composition may be applied to the release treatment surface of the release agent and dried to form two or more intermediate layers (X), and these intermediate layers (X) may be bonded together, or multiple intermediate layers (X) may be sequentially laminated on the substrate to form the intermediate layer (X). The same applies to the adhesive layer (Y).

[0107] [Applications of adhesive sheets for semiconductor processing] The semiconductor processing adhesive sheet of this embodiment is preferably used to apply a predetermined process to a substrate, such as a semiconductor device, while protecting the substrate, by being attached to the substrate. After the predetermined process is performed, the adhesive sheet of this embodiment is peeled off and removed from the substrate. In this specification, "semiconductor device" refers to any device that can function by utilizing semiconductor properties, such as semiconductor wafers, semiconductor chips, electronic components including said semiconductor chips, and electronic devices equipped with said electronic components. Among these, the adhesive sheet of this embodiment is suitable for processing semiconductor wafers.

[0108] Examples of processing performed with the adhesive sheet of this embodiment attached include backgrinding, where the other side of a semiconductor device is ground with the adhesive sheet attached to one side; dicing, where a semiconductor device is divided into individual pieces with the adhesive sheet attached to one side; transport of semiconductor devices; and pickup of semiconductor chips. Among these, the adhesive sheet of this embodiment is particularly suitable for backgrinding, and is especially suitable for backgrinding, where the back surface of a semiconductor wafer is ground with the adhesive sheet of this embodiment attached to the circuit formation surface of the semiconductor wafer.

[0109] The adhesive sheet of this embodiment is preferably used to process a semiconductor device having a surface with one or more protrusions, with the adhesive layer (Y) attached to the surface of the semiconductor device having one or more protrusions. As mentioned above, when an object having protrusions is applied, the protrusions become embedded in the adhesive layer of the adhesive sheet, making it prone to adhesive residue. On the other hand, with the adhesive sheet of this embodiment, the adhesion between the intermediate layer (X) and the adhesive layer (Y) is good, and adhesive residue can be suppressed to a high degree. Therefore, by applying it to a surface having one or more protrusions, the functions of the adhesive sheet of this embodiment can be expressed more effectively. The height of the above-mentioned protrusions is not particularly limited, but from the viewpoint of more effectively exhibiting the function of the adhesive sheet of this embodiment, it is preferably 10 μm or more, more preferably 12 μm or more, and even more preferably 14 μm or more. The height of the above-mentioned protrusions is not particularly limited, but for example, it may be 150 μm or less, 100 μm or less, or 50 μm or less. The pitch of the above-mentioned protrusions is not particularly limited, but from the viewpoint of more effectively exhibiting the function of the adhesive sheet of this embodiment, it is preferably 5 to 100 μm, more preferably 10 to 50 μm, and even more preferably 15 to 25 μm. Here, "pitch" refers to the shortest distance between the centers of adjacent protrusions in a plan view. The shape of the convex portion in plan view is not particularly limited and can be spherical, cylindrical, elliptic, ellipsoid, cone, elliptic cone, cube, rectangular prism, trapezoid, etc. A semiconductor device having a surface with one or more protrusions is preferably a semiconductor wafer having bumps as protrusions.

[0110] [Manufacturing method for semiconductor devices] The semiconductor device manufacturing method of this embodiment is a method for manufacturing a semiconductor device that includes a step of processing a semiconductor device having a surface having one or more protrusions, wherein the semiconductor device is processed with the adhesive layer (Y) of the semiconductor processing adhesive sheet of this embodiment attached to the surface having one or more protrusions of the semiconductor device.

[0111] A description of a semiconductor device having a surface with one or more protrusions, and a description of the semiconductor device and its processing, are as described in the section on the uses of the semiconductor processing adhesive sheet. Among these, the processing in the manufacturing method of the semiconductor device of this embodiment is preferably a back grinding process in which the adhesive sheet of this embodiment is attached to one surface of the semiconductor device and the other surface is ground. A known method can be used for the back grinding process. [Examples]

[0112] The present invention will be specifically described by the following examples, but the present invention is not limited to these examples. The physical properties in the following manufacturing examples and examples were measured by the following methods.

[0113] [Weight average molecular weight (Mw)] The weight-average molecular weight (Mw) was measured using a gel permeation chromatograph under the following conditions and determined on a standard polystyrene basis. (Measuring equipment) • Measuring device: Product name "HLC-8220GPC", manufactured by Tosoh Corporation • Detector: Differential refractometer • Column: One "TSK guard column HXL-H", two "TSK gel GMHXL" in series, and one "TSK gel G2000HXL" (all manufactured by Tosoh Corporation) are connected in this order from the sample inlet side. (Measurement conditions) Column temperature: 40°C • Developing solvent: tetrahydrofuran ·Flow rate: 1.0mL / min

[0114] [Thickness of adhesive sheets for semiconductor processing, etc.] The thicknesses of the substrates, intermediate layer (X), adhesive layer (Y), release agent, and semiconductor processing adhesive sheets obtained therefrom in each example and comparative example, as well as the thickness of the samples prepared for evaluation, were measured using a constant-pressure thickness gauge manufactured by Teclock Corporation [Model number: "PG-02J", Standard specifications: JIS K6783:1994, JIS Z1702:1994, JIS Z1709:1995]. Note that the total thickness of the adhesive sheet for semiconductor processing is the thickness of the adhesive sheet excluding the release agent.

[0115] [Tensile modulus of the substrate at 23°C] A substrate was prepared to a length of 100 mm and a width of 15 mm to obtain a sample for measuring the tensile modulus. Using a tensile testing machine (product name "Autograph®", manufactured by SHIMADZU), the sample was stretched in the longitudinal direction of the substrate at a speed of 200 mm / min to measure the tensile modulus, and the value of the tensile modulus (E') at 23°C was calculated from the measurement results. This value was defined as the tensile modulus of the substrate at 23°C (unit: MPa).

[0116] [Storage modulus G'(x) of the intermediate layer (X) at 23°C] The intermediate layer compositions used in the examples and comparative examples were coated with polyethylene terephthalate (PET) release films (product name "SP-PET381031", thickness 38 μm, manufactured by Lintec Corporation) on both sides using a knife coater to form a 50 μm thick intermediate layer. Multiple intermediate layers formed in this manner were prepared, and by peeling off the PET release film and sequentially laminating them with the release surfaces facing each other, a laminate of intermediate layers (thickness 1,000 μm) was prepared. Next, the resulting intermediate layer laminate was subjected to an illuminance of 230 mW / cm². 2 , light intensity 380mJ / cm 2 Ultraviolet light was irradiated under the following conditions. Then, the laminated intermediate layer, which had been irradiated with ultraviolet light, was punched out into a circle with a diameter of 10 mm to obtain a sample for measuring viscoelasticity. Using a viscoelasticity measuring device (product name "ARES", manufactured by T.A. Instruments Corporation), a strain at a frequency of 1 Hz was applied to the sample, and the storage modulus (G') was measured from -30 to 120°C at a heating rate of 10°C / min. From the measured values, the storage modulus (G') at 23°C was calculated, and this value was defined as the storage modulus G'(x) (unit: MPa) of the intermediate layer at 23°C.

[0117] [Storage modulus G'(y) of the adhesive layer (Y) at 23°C] In the measurement of the storage modulus G'(x) of the intermediate layer (X) at 23°C, the storage modulus G'(y) (unit: MPa) of the adhesive layer at 23°C was calculated using the same method as for the measurement of the storage modulus G'(x) of the intermediate layer (X), except that the intermediate layer composition was changed to the adhesive composition used in the examples and comparative examples, and the laminate formed from the adhesive layer was used as the measurement sample.

[0118] [Adhesion] For the semiconductor processing adhesive sheets prepared in the examples and comparative examples, an illuminance of 230 mW / cm was applied from the substrate side surface. 2 , light intensity 380mJ / cm 2 The intermediate layer and adhesive layer were cured by irradiating them with ultraviolet light under the specified conditions. Next, the release liner of the semiconductor processing adhesive sheet was removed, and 11 vertical x 11 horizontal cuts were made in the hardened adhesive layer at 5 mm intervals, creating a grid pattern (100 squares). The depth of the cuts was adjusted so as to completely cut through the adhesive layer (40 μm), but not so deeply into the intermediate layer (110 μm) (specifically, between 40 μm and 150 μm). Then, cellophane adhesive tape (manufactured by Nichiban Co., Ltd., product name "Cellotape (registered trademark)") was attached to the surface of the adhesive layer, and after standing at 23°C and 50% RH (relative humidity) for 20 minutes, while holding down the adhesive sheet with one hand, the end of the cellophane adhesive tape was held with the other hand and the cellophane adhesive tape was pulled in a direction perpendicular to the semiconductor processing adhesive sheet, causing it to instantly peel off from the surface of the adhesive layer of the semiconductor processing adhesive sheet. After peeling off the cellophane adhesive tape, the grid-like cuts on the adhesive layer of the semiconductor processing adhesive sheet were visually inspected. The number of squares in which delamination between the adhesive layer and the intermediate layer of the semiconductor processing adhesive sheet was observed was counted, and the adhesion between the intermediate layer and the adhesive layer of the semiconductor processing adhesive sheet after UV irradiation was evaluated. Table 1 shows the number of squares in which delamination between the intermediate layer and the adhesive layer was observed out of 100 squares. The fewer the number of squares listed in Table 1, the better the adhesion between the intermediate layer and the adhesive layer of the semiconductor processing adhesive sheet after UV irradiation.

[0119] [Manufacturing of adhesive sheets for semiconductor processing] A semiconductor processing adhesive sheet was manufactured using the method described below. In Table 1, the notation "L / M / N=S / T / U" indicating the composition of the copolymer indicates that the copolymer is a copolymer of monomer L, monomer M, and monomer N, and was obtained by copolymerizing part S by mass of monomer L, part T by mass of monomer M, and part U by mass of monomer N. Furthermore, the abbreviations for each monomer in Table 1 are as follows: 2EHA:2-Ethylhexylacrylate BA: n-butyl acrylate MMA: Methyl methacrylate VAc: vinyl acetate AA: Acrylic acid HEA: 2-hydroxyethyl acrylate MOI: 2-Methacryloyloxyethyl isocyanate For example, the description "2EHA / VAc / AA=66 / 28 / 6" indicates that the copolymer is a copolymer of 2EHA, VAc, and AA, and was obtained by copolymerizing 66 parts by mass of 2EHA, 28 parts by mass of VAc, and 6 parts by mass of AA. Furthermore, the statement "BA / MMA / HEA(MOI)=62 / 10 / 28(80%)" indicates that the copolymer is an acrylic copolymer obtained by copolymerizing 62 parts by mass of BA, 10 parts by mass of MMA, and 28 parts by mass of HEA, and that the MOI is a polymer obtained by reacting such that it is added to 80 mol% of the total hydroxyl groups of the acrylic copolymer.

[0120] [Example 1] (1) Preparation of the base material A terminal isocyanate urethane prepolymer obtained by polymerizing polycarbonate diol and isophorone diisocyanate was reacted with 2-hydroxyethyl acrylate to obtain a urethane acrylate oligomer with a weight-average molecular weight (Mw) of 5,000. 40 parts by mass of this urethane acrylate oligomer, 20 parts by mass of p-methylphenoxyethyl acrylate, 40 parts by mass of isobornyl acrylate, and 2.0 parts by mass (by solids content) of 1-hydroxycyclohexyl phenyl ketone (product name "OMNIRAD® 184", manufactured by IGM Resins BV) as a photopolymerization initiator were combined to obtain an energy-ray curable resin composition. The obtained energy-ray curable resin composition was coated onto the release surface of a PET-based release film (product name "SP-PET381031", manufactured by Lintec Corporation, thickness 38 μm), which is a casting process sheet, using a fountain die method to form a resin composition layer with a thickness of 160 μm. Immediately after coating, the resin composition layer was semi-cured using a high-pressure mercury lamp, and then the same PET-based release film was laminated onto it. Subsequently, the energy-ray curable resin composition was crosslinked and cured using a high-pressure mercury lamp. Then, the PET-based release films on both sides were peeled off to obtain a film with a thickness of 160 μm. This film was used as a substrate. Furthermore, the tensile modulus of the substrate at 23°C, as measured by the method described above, was 210 MPa. (2) Preparation of substrate with intermediate layer An acrylic copolymer (Mw=600,000) was prepared as acrylic polymer (A) by copolymerizing 66 parts by mass of 2-ethylhexyl acrylate, 28 parts by mass of vinyl acetate, and 6 parts by mass of acrylic acid. Furthermore, an acrylic copolymer (Mw=400,000) was prepared as acrylic polymer (B) by reacting 2-methacryloyloxyethyl isocyanate with an acrylic copolymer obtained by copolymerizing 62 parts by mass of n-butyl acrylate, 10 parts by mass of methyl methacrylate, and 28 parts by mass of 2-hydroxyethyl acrylate, so that 80 mol% of the total hydroxyl groups of the acrylic copolymer were added. To 100 parts by mass of the acrylic polymer (A), 50 parts by mass of acrylic polymer (B), 0.57 parts by mass of isocyanate crosslinking agent (product name "Coronate® L", manufactured by Tosoh Corporation), 0.076 parts by mass of metal chelate crosslinking agent (product name "BXX4805", manufactured by Toyo Chem Co., Ltd.), and 3.71 parts by mass of 1-hydroxycyclohexyl phenyl ketone (product name "OMNIRAD® 184", manufactured by IGM Resins BV Co., Ltd.) as a photopolymerization initiator were mixed together, diluted with toluene to a solid content concentration of 30% by mass, and stirred for 30 minutes to prepare a solution of the intermediate layer forming composition. Next, a solution of the prepared intermediate layer-forming composition was applied to the release surface of a PET-based release film (product name "SP-PET381031", manufactured by Lintec Corporation, thickness 38 μm) using the comma method, and heated and dried at 100°C for 2 minutes to form two intermediate layers with release films, each with an intermediate layer thickness of 55 μm. Next, one of the intermediate layers with a release film was bonded to the substrate prepared in (1), and then the release film on the intermediate layer was peeled off to produce a laminate. Furthermore, the other intermediate layer with a release film was bonded to the surface of the intermediate layer of the laminate to create a substrate with an intermediate layer of 270 μm thickness (intermediate layer thickness of 110 μm). (3) Preparation of adhesive composition An acrylic polymer (C) obtained by copolymerizing 80 parts by mass of 2-ethylhexyl acrylate and 20 parts by mass of 2-hydroxyethyl acrylate was reacted with 2-methacryloyloxyethyl isocyanate so as to add to 80 mol% of the total hydroxyl groups of the acrylic polymer (C) to obtain an energy-ray curable acrylic resin (Mw: 500,000). To 100 parts by mass of this energy-ray curable acrylic resin, 1 part by mass of an isocyanate-based crosslinking agent (product name "Coronate® L", manufactured by Tosoh Corporation) and 3.75 parts by mass of 1-hydroxycyclohexyl phenyl ketone (product name "OMNIRAD® 184", manufactured by IGM Resins BV) were added as a photopolymerization initiator. The mixture was then diluted with toluene to prepare a solution of an adhesive composition with a solid content of 28% by mass. (4) Fabrication of adhesive sheets for semiconductor processing A solution of the adhesive composition obtained in (3) above was applied to the release surface of a PET-based release film (product name "SP-PET381031", manufactured by Lintec Corporation, thickness 38 μm) using a comma method, and heated and dried at 100°C for 2 minutes to form an adhesive layer with a thickness of 40 μm on the PET-based release film. Next, the adhesive layer was bonded to the surface of the intermediate layer-attached substrate obtained in (2) above, to produce an adhesive sheet for semiconductor processing consisting of a substrate (160 μm) / intermediate layer (110 μm) / adhesive layer (40 μm) / release agent (38 μm).

[0121] [Examples 2 and 3, and Comparative Examples 1 and 2] A semiconductor processing adhesive sheet was prepared in the same manner as in Example 1, except that the acrylic polymer (A) used in the intermediate layer was changed to an acrylic polymer formed from the monomer compositions shown in Table 1.

[0122] [Comparative Example 3] A semiconductor processing adhesive sheet was prepared in the same manner as in Example 1, except that the solution of the intermediate layer forming composition was changed to the solution of the intermediate layer forming composition shown below. (Preparation of the intermediate layer forming composition used in Comparative Example 3) An acrylic copolymer (A-2) (Mw=600,000) obtained by copolymerizing 91 parts by mass of n-butyl acrylate and 9 parts by mass of acrylic acid was prepared as the acrylic polymer (A). Furthermore, an acrylic copolymer (B-2) (Mw=100,000) was prepared as acrylic polymer (B) by reacting 2-methacryloyloxyethyl isocyanate with an acrylic copolymer obtained by copolymerizing 62 parts by mass of n-butyl acrylate, 10 parts by mass of methyl methacrylate, and 28 parts by mass of 2-hydroxyethyl acrylate, so as to add 80 mol% of the hydroxyl groups of the acrylic copolymer. To prepare a solution of the intermediate layer-forming composition, 100 parts by mass of the acrylic polymer (A) was mixed with 50 parts by mass of acrylic polymer (B), 2.8 parts by mass of an isocyanate crosslinking agent (product name "Coronate® L", manufactured by Tosoh Corporation), and 2.1 parts by mass of 1-hydroxycyclohexyl phenyl ketone (product name "OMNIRAD® 184", manufactured by IGM Resins BV) as a photopolymerization initiator. The mixture was then diluted with toluene to a solid content concentration of 30% by mass and stirred for 30 minutes.

[0123] [Table 1]

[0124] As shown in Table 1, the semiconductor processing adhesive sheets of Examples 1 to 3 that satisfy the aforementioned requirement (1) were confirmed to have excellent adhesion between the intermediate layer and the adhesive layer after ultraviolet irradiation. Therefore, the semiconductor processing adhesive sheets of Examples 1 to 3 can suppress delamination that occurs between the intermediate layer and the adhesive layer when peeling them off a substrate such as a semiconductor device after they have been attached to the substrate. On the other hand, in the semiconductor processing adhesive sheets of Comparative Examples 1 to 3, which did not meet the aforementioned requirement (1), it was confirmed that the adhesion between the intermediate layer and the adhesive layer after ultraviolet irradiation was significantly inferior to that of Examples 1 to 3.

Claims

1. An adhesive sheet for semiconductor processing comprising, in this order, a base material, an intermediate layer (X) having energy ray curability and containing an acrylic polymer, and an adhesive layer (Y) containing an acrylic polymer, and satisfying the following requirement (1). Requirement (1): Illuminance 230mW / cm ２ , light intensity 380mJ / cm ２ Using the storage modulus G'(x) (in MPa) of the intermediate layer (X) at 23°C after irradiation with ultraviolet light under the specified conditions, and the storage modulus G'(y) (in MPa) of the adhesive layer (Y) at 23°C, the Q value (in MPa) calculated by the following formula (1) is between -30 and 30. Q = {G'(y) - (G'(x) × 40)} ... Equation (1)

2. The semiconductor processing adhesive sheet according to claim 1, wherein the storage modulus G'(x) is 2.00 MPa or less.

3. The semiconductor processing adhesive sheet according to claim 1 or 2, wherein the storage modulus G'(y) is 10.0 MPa or more.

4. The semiconductor processing adhesive sheet according to any one of claims 1 to 3, wherein the intermediate layer (X) is formed from an intermediate layer forming composition comprising an acrylic polymer (A) and an acrylic polymer (B), and the weight-average molecular weight of the acrylic polymer (A) is greater than the weight-average molecular weight of the acrylic polymer (B).

5. The semiconductor processing adhesive sheet according to claim 4, wherein the weight-average molecular weight of the acrylic polymer (B) is greater than 250,000.

6. The semiconductor processing adhesive sheet according to claim 4 or 5, wherein the weight-average molecular weight of the acrylic polymer (A) is greater than 450,000.

7. The semiconductor processing adhesive sheet according to any one of claims 4 to 6, wherein the acrylic polymer (A) is a non-energy ray curable acrylic polymer, and the acrylic polymer (B) is an energy ray curable acrylic polymer.

8. The acrylic polymer (A) is an acrylic copolymer (A1) having structural units derived from alkyl (meth)acrylate (a1) and structural units derived from functional group-containing monomer (a2), wherein the alkyl (meth)acrylate (a1) contains 2-ethylhexyl (meth)acrylate, as described in any one of claims 4 to 7, for use as an adhesive sheet for semiconductor processing.

9. The semiconductor processing adhesive sheet according to claim 8, wherein the content of constituent units derived from functional group-containing monomers (a2) in the acrylic copolymer (A1) is 3 to 11% by mass of the total constituent units (100% by mass) of the acrylic copolymer (A1).

10. The semiconductor processing adhesive sheet according to any one of claims 4 to 9, wherein the content of the acrylic polymer (B) in the intermediate layer forming composition is 30 parts by mass or more per 100 parts by mass of the acrylic polymer (A).

11. The semiconductor processing adhesive sheet according to any one of claims 1 to 10, wherein the tensile modulus of the substrate is 50 MPa or more.

12. A semiconductor processing adhesive sheet according to any one of claims 1 to 11, used for processing a semiconductor device, the semiconductor device having a surface with one or more protrusions, with the adhesive layer (Y) attached to the surface of the semiconductor device having one or more protrusions.

13. A method for manufacturing a semiconductor device, which includes a step of processing a semiconductor device having a surface with one or more protrusions, A method for manufacturing a semiconductor device, comprising processing the semiconductor device while the adhesive layer (Y) of the semiconductor processing adhesive sheet described in any one of claims 1 to 11 is attached to a surface of the semiconductor device having one or more protrusions.

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