Adhesive sheets for semiconductor processing

Abstract

The objective of this invention is to provide an adhesive sheet for semiconductor processing that is also suitable for applications involving high-temperature processes. The solution of this invention is to provide an adhesive sheet for semiconductor processing comprising an adhesive layer constituting the adhesive surface. In one embodiment of the aforementioned adhesive sheet for semiconductor processing, the initial conventional peel force Fd0 is 0.10 N / 20 mm or more, and the conventional peel force Fd0 after heat treatment at 150°C for 15 minutes is... a It is below 1.00N / 20mm.

Description

Technical Field

[0001] This invention relates to adhesive sheets for semiconductor processing. Background Technology

[0002] In the manufacturing process of semiconductor devices, for processes such as grinding and cutting of semiconductor wafers that have formed circuits, in order to protect and fix the semiconductor wafer, the process is usually performed with an adhesive sheet (semiconductor processing adhesive sheet) attached to the circuit forming side of the semiconductor wafer (the object to be bonded). For example, when grinding the back side of a semiconductor wafer (backgrind), backgrind tape is used to protect the circuit forming side (front side) of the semiconductor wafer and to hold (fix) the semiconductor wafer (for example, Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-212441 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] For back-grinding tapes and other adhesive sheets used in semiconductor processing, after fulfilling their intended purpose, they must be peeled off from the substrate at the desired time. Therefore, for semiconductor processing adhesive sheets, a good balance is required to simultaneously achieve good adhesion to the substrate during processing, reliable bonding, and good peelability when peeled off. However, even for semiconductor processing adhesive sheets that achieve these characteristics well in a balanced manner within a room temperature range, the peel force increases significantly when exposed to high temperatures above a specified temperature after being attached to the substrate. This can result in adhesive residue on the substrate and damage to the substrate due to the load during peeling. In particular, in recent years, with the miniaturization, thinning, and high integration of semiconductor devices, there is a trend towards thinner semiconductor wafers after back-grinding. There is a need for semiconductor processing adhesive sheets that can peel off while suppressing the load on the substrate even after processing at high temperatures (high-temperature processes).

[0008] The present invention was made in view of the above circumstances, and the object is to provide an adhesive sheet for semiconductor processing that is also suitable for use in processes including high-temperature processes.

[0009] Methods for solving problems

[0010] The semiconductor processing adhesive sheet disclosed in this specification includes an adhesive layer constituting the adhesive surface. In some embodiments of the aforementioned semiconductor processing adhesive sheet (hereinafter, sometimes simply referred to as "adhesive sheet"), the initial conventional peel force Fd0 of the adhesive sheet is 0.10 N / 20 mm or more (hereinafter also referred to as "Condition A"), and the conventional peel force Fd0 after heat treatment at 150°C for 15 minutes is [not specified in the original text]. a The value is 1.00 N / 20 mm or less (hereinafter also referred to as "Condition B"). This limits the lower limit of the initial conventional peel force Fd0 and the conventional peel force Fd after heat treatment at 150°C for 15 minutes, as described above. a For adhesive sheets with an upper limit of (hereinafter also referred to as "normal peel force after heating to 150°C"), even in applications involving high-temperature processes, a good balance can be achieved simultaneously in terms of adhesion to the substrate during processing, bonding reliability, and peelability when peeling from the substrate.

[0011] In some embodiments of the semiconductor processing adhesive sheet disclosed in this specification, the adhesive sheet satisfies the above condition A, and the water peeling force Fw is measured by supplying water to the peeling front of the adhesive sheet after heat treatment at 150°C for 15 minutes and peeling it off from the substrate. a The value is below 0.30 N / 20 mm (hereinafter, also referred to as "Condition C"). This limits the lower limit of the initial conventional peel force Fd0 and the water peel force Fw after heat treatment at 150°C for 15 minutes, as described above. a For adhesive sheets with an upper limit of (hereinafter also referred to as "water peeling force after heating to 150°C"), even in applications involving high-temperature processes, a good balance can be achieved simultaneously in terms of adhesion to the substrate during processing, bonding reliability, and peelability when peeling from the substrate. By using the water peeling method for peeling from the substrate, the load on the substrate can be further reduced.

[0012] In some embodiments of the semiconductor processing adhesive sheet disclosed in this specification, the adhesive sheet satisfies condition A above, and has a conventional peel strength Fd after heat treatment at 200°C for 15 minutes. b The value is 3.00 N / 20 mm or less (hereinafter, also referred to as "Condition D"). This limits the lower limit of the initial conventional peel force Fd0 and the conventional peel force Fd after heat treatment at 200°C for 15 minutes, as described above. b For adhesive sheets with an upper limit of (hereinafter also referred to as "normal peel force after heating to 200°C"), even in high-temperature processes with more stringent conditions, a good balance can be achieved simultaneously in terms of adhesion to the substrate during processing, bonding reliability, and peelability when peeling from the substrate.

[0013] In some embodiments of the semiconductor processing adhesive sheet disclosed in this specification, the adhesive sheet satisfies the above condition A, and the water peeling force Fw is measured by supplying water to the peeling front of the adhesive sheet after heat treatment at 200°C for 15 minutes and peeling it off from the substrate. b The value is below 2.00 N / 20 mm (hereinafter, also referred to as "Condition E"). This limits the lower limit of the initial conventional peel force Fd0 and the water peel force Fw after heat treatment at 200°C for 15 minutes, as described above. b For adhesive sheets with an upper limit of (hereinafter also referred to as "water peeling force after heating to 200°C"), even in high-temperature processes with more stringent conditions, a good balance can be achieved simultaneously in terms of adhesion to the substrate during processing, bonding reliability, and peelability when peeling from the substrate. By using the water peeling method for peeling from the substrate, the load on the substrate can be further reduced.

[0014] In some methods of semiconductor processing adhesive sheets disclosed in this specification, for such adhesive sheets, the conventional peel force Fd after heat treatment at 150°C for 15 minutes is... a [N / 20mm] and the standard peel strength Fd after heat treatment at 200℃ for 15 minutes. b [N / 20mm], determined by the following formula: Fd b / Fd a The calculated standard peel strength ratio is below 4.0. Therefore, for adhesive sheets, even if uneven processing occurs during high-temperature processes, the peel strength is not easily affected.

[0015] In some methods of semiconductor processing adhesive sheets disclosed in this specification, for such adhesive sheets, the conventional peel force Fd after heat treatment at 150°C for 15 minutes is... a [N / 20mm] and the standard peel strength Fd after heat treatment at 200℃ for 15 minutes. b [N / 20mm], determined by the following formula: Fd b -Fd a The calculated difference in typical peel force is below 1.50 N / 20 mm. Therefore, for adhesive sheets, even if uneven processing occurs during high-temperature processes, the peel force is not easily affected.

[0016] It should be noted that the scope of the invention for which this patent application seeks patent protection may also include solutions that appropriately combine the above-mentioned elements. Attached Figure Description

[0017] [ Figure 1 This is a cross-sectional view schematically illustrating a structural example of an adhesive sheet.

[0018] [ Figure 2 This is a cross-sectional view schematically illustrating another structural example of an adhesive sheet.

[0019] [ Figure 3 This is a cross-sectional view schematically illustrating another structural example of an adhesive sheet.

[0020] [ Figure 4 This is a cross-sectional view schematically illustrating another structural example of an adhesive sheet.

[0021] [ Figure 5 This is a cross-sectional view schematically illustrating another structural example of an adhesive sheet.

[0022] [ Figure 6 This is a cross-sectional view schematically illustrating another structural example of an adhesive sheet.

[0023] Explanation of reference numerals in the attached figures

[0024] 1, 2, 3, 4, 5, 6 Adhesive sheets

[0025] 10 Substrate

[0026] 10A First Page

[0027] 10B Second Page

[0028] 21, 22 Adhesive layers

[0029] 21A First Adhesive Surface

[0030] 21B Second Adhesive Surface

[0031] 31, 32 Peeling off the gasket Detailed Implementation

[0032] The preferred embodiments of the present invention will be described below. It should be noted that matters necessary for the implementation of the present invention, other than those specifically described in this specification, can be understood by those skilled in the art based on the teachings on implementing the invention as described in this specification and common technical knowledge at the time of application. The present invention can be implemented based on the disclosure in this specification and common technical knowledge in the field. Furthermore, in the following drawings, sometimes the same reference numerals are used to describe components or parts that perform the same function, and sometimes repeated descriptions are omitted or simplified. Also, the embodiments described in the drawings are schematic for the purpose of clearly illustrating the present invention and do not necessarily accurately represent the dimensions or proportions of the actual provided article.

[0033] In this specification, the method of peeling adhesive sheets from the substrate using water or other water-based stripping fluid (typically, the method of peeling by supplying water-based stripping fluid to the peeling front of the substrate) is sometimes referred to as "water peeling" or "water peeling method".

[0034] In this specification, the term "acrylic polymer" refers to a polymer derived from a monomeric raw material containing more than 50% by weight (preferably more than 70% by weight, for example more than 90% by weight) of an acrylic monomer. The aforementioned acrylic monomer refers to a monomer having at least one (meth)acryloyl group in one molecule. Furthermore, in this specification, the term "(meth)acryloyl" means including both acryloyl and methacryloyl groups. Similarly, the term "(meth)acrylate" means including both acrylate and methacrylate, and the term "(meth)propylene-" means including both propylene- and methpropylene-.

[0035] In addition, in this specification, the term "active energy rays" refers to the concept of light such as ultraviolet rays, visible light, and infrared rays, as well as radiation such as alpha rays, beta rays, gamma rays, electron beams, neutron beams, and X-rays.

[0036] <Example of adhesive sheet structure>

[0037] The adhesive sheet disclosed in this specification has an adhesive layer. Typically, the adhesive layer forms at least one surface of the adhesive sheet. The adhesive sheet can be a substrate-supported adhesive sheet having an adhesive layer on one or both sides of a substrate (support), or it can be an adhesive sheet without a substrate (substrate-free adhesive sheet).

[0038] The concept of adhesive sheet as used herein can include products referred to as adhesive tape, adhesive label, adhesive film, etc. Furthermore, the adhesive layer described above is typically formed continuously, but is not limited to the aforementioned form; for example, it can be an adhesive layer formed as regular or irregular patterns such as dots or stripes. Additionally, the adhesive sheet provided in this specification can be in roll form or as a single sheet. Alternatively, it can be an adhesive sheet that has been further processed into various shapes.

[0039] The adhesive sheet disclosed in this specification may, for example, have... Figures 1-6 The cross-sectional structure of the adhesive sheet is schematically shown in the diagram. Among them, Figure 1 , Figure 2 This is a structural example of a single-sided adhesive sheet with a substrate (a single-sided adhesive sheet with a substrate). Figure 1 The adhesive sheet 1 shown has an adhesive layer 21 provided on one side 10A (non-peelable) of the substrate 10, and the surface (adhesive surface) 21A of the adhesive layer 21 is protected by a release liner 31 that at least the adhesive layer side becomes the release surface. Figure 2The adhesive sheet 2 shown has a structure in which an adhesive layer 21 is provided on one side 10A (non-peelable) of the substrate 10. For this adhesive sheet 2, the other side 10B of the substrate 10 becomes the peeling side. If the adhesive sheet 2 is rolled up, the adhesive layer 21 abuts against the other side 10B, and the surface (adhesive side) 21A of the adhesive layer will be protected by the other side 10B of the substrate 10.

[0040] Figure 3 , Figure 4 This is a structural example of a double-sided adhesive sheet with a substrate (a double-sided adhesive sheet with a substrate). Figure 3 The adhesive sheet 3 shown has the following structure: an adhesive layer (first adhesive layer) 21 and an adhesive layer (second adhesive layer) 22 are respectively provided on the first surface 10A and the second surface 10B (both non-peelable) of the substrate 10. The surface of the first adhesive layer 21 (first adhesive surface) and the surface of the second adhesive layer 22 (second adhesive surface) are respectively protected by release liner 31 and 32, which at least the adhesive layer side serves as the release surface. Figure 4 The adhesive sheet 4 shown has the following structure: a first adhesive layer 21 and a second adhesive layer 22 are respectively provided on the first surface 10A and the second surface 10B (both non-peelable) of the substrate 10. The surface of the first adhesive layer 21 (first adhesive surface) is protected by a release liner 31, which has two sides that are peelable surfaces. For the adhesive sheet 4, by winding the adhesive sheet 4 so that the surface of the second adhesive layer 22 (second adhesive surface) abuts against the back of the release liner 31, a structure can be formed in which the second adhesive surface is also protected by the release liner 31.

[0041] Figure 5 , Figure 6 This is a structural example of a substrate-free double-sided adhesive sheet (substrate-free double-sided adhesive sheet). Figure 5 The adhesive sheet 5 shown has a structure in which one surface (first adhesive surface) 21A and the other surface (second adhesive surface) 21B of the substrate-free adhesive layer 21 are respectively protected by release liner 31, 32 which at least the adhesive layer side serves as the release surface. Figure 6 The adhesive sheet 6 shown has a structure in which one surface (first adhesive surface) 21A of the adhesive layer 21 is protected by a release liner 31 on both sides, which are called release surfaces. If it is wound up, the other surface (second adhesive surface) 21B of the adhesive layer 21 abuts against the back of the release liner 31, thereby forming a structure in which the other side 21B is also protected by the release liner 31.

[0042] For double-sided adhesive sheets with or without a substrate, they can be used as single-sided adhesive sheets with a substrate by attaching a non-peelable substrate to one of the adhesive surfaces.

[0043] Before use (before attaching to the object), the adhesive sheet can be, for example, such as... Figures 1-6 The adhesive sheet shown is in the form of a release liner with an adhesive surface protected by a release liner. There are no particular limitations on the release liner; for example, a release liner whose surface has been treated with a release agent, such as a resin film or paper liner substrate, or a release liner made of a low-adhesion material such as a fluoropolymer (polytetrafluoroethylene, etc.) or a polyolefin resin (polyethylene, polypropylene, etc.) can be used. In the aforementioned release treatment, for example, a release agent based on silicone or long-chain alkyl groups can be used. In some embodiments, a resin film that has undergone release treatment is preferably used as the release liner.

[0044] When the adhesive sheet disclosed in this specification is in the form of a double-sided adhesive sheet with a substrate or a double-sided adhesive sheet without a substrate, the adhesive constituting the first adhesive surface (first adhesive) and the adhesive constituting the second adhesive surface (second adhesive) may have the same composition or different compositions. For example, a double-sided adhesive sheet without a substrate in which the composition of the first adhesive surface and the composition of the second adhesive surface are different can be achieved by directly (without a substrate) laminating two or more adhesive layers with different compositions into a multilayer adhesive layer structure.

[0045] <Adhesive layer>

[0046] The adhesive layer constituting the adhesive surface of the adhesive sheet disclosed in this specification may be an adhesive layer comprising one or more adhesives selected from a variety of known adhesives, including acrylic adhesives, rubber adhesives (natural rubber, synthetic rubber, mixtures thereof, etc.), polysiloxane adhesives, polyester adhesives, urethane adhesives, polyether adhesives, polyamide adhesives, and fluorinated adhesives. Here, "acrylic adhesive" refers to an adhesive based on an acrylic polymer. The same meaning applies to other adhesives such as rubber adhesives.

[0047] It should be noted that, in this specification, the term "base polymer" in the adhesive refers to the main component of the polymer contained in the adhesive. Furthermore, unless otherwise specified, the term "main component" in this specification refers to the component contained in an amount exceeding 50% by weight.

[0048] (Acrylic adhesive layer)

[0049] In some embodiments of the adhesive sheet disclosed in this specification, the adhesive layer may be an acrylic adhesive layer containing an acrylic adhesive as the main component. In adhesive sheets having an acrylic adhesive layer, it is suitable to simultaneously achieve adhesive properties suitable for semiconductor processing and easy peelability based on water peeling.

[0050] As an acrylic adhesive, it is preferable to use an acrylic polymer as the base polymer, wherein the acrylic polymer is a polymer containing a monomer raw material of (meth)acrylate. As a component of the aforementioned monomer raw material, a (meth)acrylate alkyl ester is preferably used that has a straight-chain or branched alkyl group having 1 or more and 20 or fewer carbon atoms at the ester terminus. Hereinafter, a (meth)acrylate alkyl ester having an alkyl group having X or more and Y or fewer carbon atoms at the ester terminus is sometimes referred to as "(meth)acrylate C". X-Y Alkyl ester. Considering the ease of obtaining adhesive properties suitable for semiconductor processing applications, (meth)acrylic acid C... 1-20 Alkyl ester, preferably (meth)acrylic acid C 1-14 (e.g., C) 1-12 Alkyl esters. Additionally, as acrylic acid C... 1-20 Alkyl ester, preferably C14 acrylic acid 1-20 (e.g., C) 1-14 Typically C 1-12 Alkyl esters.

[0051] As (meth)acrylic acid C 1-20 Non-limiting specific examples of alkyl esters include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, pentyl methacrylate, isoamyl methacrylate, hexyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, isooctyl methacrylate, nonyl methacrylate, isononyl methacrylate, decyl methacrylate, isodecanyl methacrylate, undecyl methacrylate, dodecyl methacrylate, tridecyl methacrylate, tetradecyl methacrylate, pentadecyl methacrylate, hexadecyl methacrylate, heptadecanyl methacrylate, octadecyl methacrylate, nonadecanyl methacrylate, eicosyl methacrylate, etc. These alkyl (meth)acrylates can be used alone or in combination of two or more. Preferred alkyl (meth)acrylates include ethyl acrylate (EA), n-butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), and lauryl acrylate (LA). In some embodiments, the monomer raw material preferably contains at least one of EA, BA, 2EHA, and LA; more preferably, it contains at least one of EA, BA, and 2EHA; and even more preferably, it contains at least one of BA and 2EHA.

[0052] Considering the ease of obtaining a balance of properties, in some methods, (meth)acrylic acid C1-20 The proportion of alkyl esters in the aforementioned monomer raw materials is typically suitable to be 40% by weight or more, preferably more than 50% by weight, for example, it can be 55% by weight or more, 60% by weight or more, 65% by weight or more, or 70% by weight or more. For the same reason, the (meth)acrylic acid C in the aforementioned monomer raw materials... 1-20 The proportion of alkyl esters is typically suitable to be 99.9% by weight or less, and can be 99% by weight or less, or 98% by weight or less. From the viewpoint of easily forming adhesive sheets suitable for lightly peeling based on supplying an aqueous release agent to the peel front from the adherend, in some embodiments, the (meth)acrylic acid C in the aforementioned monomer raw materials... 1-20 The proportion of alkyl esters can be, for example, less than 95% by weight, less than 85% by weight, less than 80% by weight, less than 70% by weight, or less than 65% by weight.

[0053] The monomer feedstocks used in the synthesis of acrylic polymers may also include secondary monomers that are copolymerizable with the aforementioned alkyl (meth)acrylates. These secondary monomers can help introduce crosslinking points into the acrylic polymers or improve their cohesiveness.

[0054] As a secondary monomer, one or more monomers containing functional groups can be used alone or in combination, such as the following.

[0055] Monomers containing hydroxyl groups: such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, methyl methacrylate (4-hydroxymethylcyclohexyl) ester, etc. (meth)acrylate hydroxyalkyl esters; unsaturated alcohols such as vinyl alcohol and allyl alcohol; ether compounds such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, etc.

[0056] Monomers containing carboxyl groups: for example, olefinic unsaturated monocarboxylic acids such as acrylic acid (AA), methacrylic acid (MAA), crotonic acid, and isocrotonic acid; olefinic unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, and citraconic acid.

[0057] Monomers containing anhydride groups: for example, maleic anhydride and itaconic anhydride.

[0058] Monomers having a ring containing a nitrogen atom: for example, N-vinyl-2-pyrrolidone, methyl-N-vinylpyrrolidone, vinylpyridine, vinylpyrazine, vinylpyrimidine, N-vinylpiperidone, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazolium, N-vinyloxazole, N-vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole, N-vinylisothiazole, N-(meth)acryloylmorpholine, N-(meth)acryloyl-2-pyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, etc.

[0059] Monomers containing an amide group: for example, (meth)acrylamide; N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, N,N-di(n-butyl)(meth)acrylamide, N,N-di(tert-butyl)(meth)acrylamide, etc.; N-alkyl(meth)acrylamides such as N-ethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-butyl(meth)acrylamide, N-n-butyl(meth)acrylamide; N-vinylcarboxylic acid amides such as N-vinylacetamide; monomers having both hydroxyl and amide groups, for example, N-(2-hydroxyethyl)(methyl)acrylamide. Acrylamide, N-(2-hydroxypropyl)(methyl)acrylamide, N-(1-hydroxypropyl)(methyl)acrylamide, N-(3-hydroxypropyl)(methyl)acrylamide, N-(2-hydroxybutyl)(methyl)acrylamide, N-(3-hydroxybutyl)(methyl)acrylamide, N-(4-hydroxybutyl)(methyl)acrylamide, and other N-hydroxyalkyl(methyl)acrylamides; monomers having alkoxy and amide groups, such as N-alkoxyalkyl(methyl)acrylamide, N-methoxyethyl(methyl)acrylamide, N-butoxymethyl(methyl)acrylamide, and other N-alkoxyalkyl(methyl)acrylamides; N,N-dialkylaminoalkyl(methyl)acrylamides, such as N,N-dimethylaminopropyl(methyl)acrylamide, etc.

[0060] Monomers containing amino groups: for example, aminoethyl methacrylate, N,N-dimethylaminoethyl methacrylate, and tert-butylaminoethyl methacrylate.

[0061] Monomers having a succinimide backbone: for example, N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryloyl-8-oxyhexamethylenesuccinimide, etc.

[0062] Maleimides: For example, N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide, etc.

[0063] Itaconimides: For example, N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide, etc.

[0064] Monomers containing epoxy groups: for example, glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, and allyl glycidyl ether.

[0065] Monomers containing cyano groups: such as acrylonitrile and methacrylonitrile.

[0066] Monomers containing ketone groups: such as diacetone (meth)acrylamide, diacetone (meth)acrylate, vinyl methyl ketone, vinyl ethyl ketone, allyl acetoacetate, and vinyl acetoacetate.

[0067] Monomers containing alkoxysilyl groups: such as 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, etc., as well as vinyl compounds containing alkoxysilyl groups such as (meth)acrylates, vinyltrimethoxysilane, vinyltriethoxysilane, etc.

[0068] Monomers containing amino groups: for example, aminoethyl methacrylate, N,N-dimethylaminoethyl methacrylate, and tert-butylaminoethyl methacrylate.

[0069] Monomers with epoxy groups: for example, glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, and allyl glycidyl ether.

[0070] Monomers containing sulfonic acid or phosphoric acid groups: for example, styrene sulfonic acid, allyl sulfonic acid, sodium vinyl sulfonate, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, (meth)acrylate sulfopropyl ester, (meth)acryloyloxynaphthalene sulfonic acid, acryloyl phosphate 2-hydroxyethyl ester, etc.

[0071] Monomers containing isocyanate groups: for example, ethyl (meth)acrylate, methacryloyl isocyanate, and m-isopropenyl-α,α-dimethylbenzyl isocyanate.

[0072] The amount of the aforementioned monomers containing functional groups can be appropriately selected in a way that achieves the desired cohesiveness, without particular limitation. Generally, from the viewpoint of achieving good balance between cohesiveness and other properties (e.g., adhesiveness), the amount of monomers containing functional groups (the total amount when using two or more monomers containing functional groups) is preferably 0.1% by weight or more, preferably 0.3% by weight or more, for example, 1% by weight or more, of the total monomer raw material. Alternatively, the amount of monomers containing functional groups can be, for example, 50% by weight or less, or 40% by weight or less, of the total monomer raw material. From the viewpoint of easily suppressing the increase in peeling force due to heating, in some embodiments, the amount of monomers containing functional groups can be 30% by weight or less, 25% by weight or less, 20% by weight or less, 10% by weight or less, or 5% by weight or less, of the total monomer raw material.

[0073] In some embodiments, the aforementioned monomer raw material may include a monomer containing hydroxyl groups as the monomer containing the aforementioned functional group. There is no particular limitation on the amount of hydroxyl-containing monomer used; for example, it may be 0.01% by weight or more, 0.1% by weight or more, 0.5% by weight or more, 1% by weight or more, 5% by weight or more, or 10% by weight or more of the total monomer raw material. In some embodiments, the amount of hydroxyl-containing monomer used may be, for example, less than 50% by weight of the total monomer raw material. From the viewpoint of suppressing water absorption of the adhesive, it is generally suitable to be less than 40% by weight, less than 30% by weight, less than 25% by weight, or less than 20% by weight. Furthermore, in some embodiments, the amount of hydroxyl-containing monomer used may be less than 15% by weight, less than 10% by weight, or less than 5% by weight of the total monomer raw material. Alternatively, hydroxyl-containing monomers may not be used.

[0074] In some embodiments, the aforementioned monomer raw materials may include monomers containing carboxyl groups as the aforementioned monomers containing functional groups. The proportion of carboxyl-containing monomers in the total monomer raw materials used in the synthesis of acrylic polymers may, for example, be 15% by weight or less, or 10% by weight or less; from the viewpoint of suppressing water absorption in the adhesive layer during semiconductor processing, it is preferably 7% by weight or less, or 5% by weight or less, or 3% by weight or less. The aforementioned monomer raw materials may substantially not contain monomers containing carboxyl groups. Here, "substantially not containing monomers containing carboxyl groups" means that monomers containing carboxyl groups are at least not intentionally used.

[0075] In some embodiments, the monomer raw materials may include monomers having nitrogen atoms as the aforementioned monomers containing functional groups. By using monomers having nitrogen atoms, a suitable degree of polarity can be imparted to the adhesive. This can be advantageous for achieving a lightly peelable adhesive sheet suitable for supplying aqueous release liquids such as water. As a preferred example of a monomer having nitrogen atoms, a monomer having a ring containing nitrogen atoms can be cited. From the viewpoint of compatibility, N-vinyl-2-pyrrolidone and other N-vinyl-type compounds (such as N-vinyl cyclic amides), and N-(meth)acryloylmorpholine and other N-(meth)acryloyl-type compounds are preferred as monomers having a ring containing nitrogen atoms.

[0076] There is no particular limitation on the amount of monomers containing nitrogen atoms (e.g., monomers with a ring containing nitrogen atoms) used, for example, it can be 1% or more, 2% or more, 3% or more, 5% or more, or 7% or more of the total monomer raw material. From the viewpoint of obtaining higher performance, in some embodiments, the amount of monomers containing nitrogen atoms used can be 10% or more, 15% or more, or 20% or more of the total monomer raw material. Furthermore, from the viewpoint of easily achieving a balance of properties, the amount of monomers containing nitrogen atoms used is generally suitable to be, for example, 40% or less, 35% or less, 30% or less, or 25% or less of the total monomer raw material. In some embodiments, the amount of monomers containing nitrogen atoms used can be, for example, 20% or less, 15% or less, 10% or less, or 5% or less of the total monomer raw material. Alternatively, monomers containing nitrogen atoms may not be used.

[0077] For the monomer raw materials that can be used in the preparation of acrylic polymers, in order to improve the cohesiveness of the acrylic polymer, other than the monomers containing functional groups mentioned above (hereinafter also referred to as comonomers) may be included.

[0078] As a specific, non-limiting example of the aforementioned copolymerizable monomers, the following examples can be cited.

[0079] Monomers containing alkoxy groups: for example, alkoxyalkyl (meth)acrylates such as 2-methoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, and 2-ethoxyethyl (meth)acrylate (alkoxyalkyl meth)acrylates; alkoxy(poly)alkylene glycol (meth)acrylates such as methoxy polyethylene glycol (meth)acrylate, methoxy polyethylene glycol (meth)acrylate, and methoxy polypropylene glycol (meth)acrylate.

[0080] Vinyl esters: such as vinyl acetate, vinyl propionate, etc.

[0081] Vinyl ethers: For example, vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.

[0082] Aromatic vinyl compounds: for example, styrene, α-methylstyrene, vinyltoluene, etc.

[0083] Olefins: such as ethylene, butadiene, isoprene, isobutene, etc.

[0084] (Meth)acrylates containing alicyclic hydrocarbon groups: for example, cyclopentyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, dicyclopentanyl(meth)acrylate, adamantyl methacrylate, and other (meth)acrylates containing alicyclic hydrocarbon groups.

[0085] (Meth)acrylates containing an aromatic ring: for example, aryl methacrylates such as phenyl methacrylate, aryl methacrylates such as phenoxyethyl methacrylate, and aryl methacrylates such as benzyl methacrylate.

[0086] In addition, (meth)acrylates containing heterocyclic rings such as tetrahydrofurfuryl methacrylate, monomers containing halogen atoms such as vinyl chloride and (meth)acrylates containing fluorine atoms, monomers containing organosiloxane chains such as polysiloxane (meth)acrylates, and (meth)acrylates obtained from terpene compound derivative alcohols, etc.

[0087] Such comonomers can be used alone or in combination of two or more. There are no particular restrictions on the amount of the other comonomers mentioned above, and they can be selected appropriately according to the purpose and use. For example, it is preferred to be less than 20% by weight of all monomer raw materials of acrylic polymers (e.g., 2 to 20% by weight, typically 3 to 10% by weight).

[0088] In a preferred embodiment, from the viewpoint of inhibiting gelation, the total proportion of alkoxyalkyl methacrylate and alkoxypolyalkylene glycol (meth)acrylate in the monomer raw material is preferably limited to less than 20% by weight. More preferably, the total proportion of alkoxyalkyl methacrylate and alkoxypolyalkylene glycol (meth)acrylate is less than 10% by weight, further preferably less than 3% by weight, and particularly preferably less than 1% by weight. In one embodiment, the monomer raw material substantially does not contain alkoxyalkyl methacrylate and alkoxypolyalkylene glycol (meth)acrylate (in a content of 0-0.3% by weight).

[0089] Similarly, in one embodiment, the monomer raw material may contain alkoxy-containing monomers in a proportion of less than 20% by weight, or may not contain alkoxy-containing monomers. The amount of alkoxy-containing monomers in the monomer raw material is preferably less than 10% by weight, more preferably less than 3% by weight, even more preferably less than 1% by weight, and in a particularly preferred embodiment, the monomer raw material substantially does not contain alkoxy-containing monomers (in a content of 0 to 0.3% by weight).

[0090] There are no particular limitations on the method for polymerizing the monomer feedstock, and various polymerization methods known as synthesis methods for acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization, can be appropriately used. For example, solution polymerization is preferred. As for the monomer supply method during solution polymerization, appropriate methods such as simultaneous charging of all monomer feedstocks, continuous supply (droplet addition), and batch supply (droplet addition) can be used. The solvent (polymerization solvent) used in solution polymerization can be appropriately selected from existing known organic solvents. For example, any one solvent or a mixture of two or more solvents selected from aromatic compounds such as toluene (typically aromatic hydrocarbons); esters such as ethyl acetate and butyl acetate; aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane; haloalkanes such as 1,2-dichloroethane; lower alcohols such as isopropanol (e.g., monohydric alcohols with 1 to 4 carbon atoms); ethers such as tert-butyl methyl ether; ketones such as methyl ethyl ketone; etc. can be used. The polymerization temperature can be appropriately selected according to the type of monomer and solvent used, the type of polymerization initiator, etc., for example, it can be around 20℃ to 120℃ (typically, 40℃ to 80℃). Solution polymerization yields a polymerization reaction solution in which the polymer of the monomer raw material is dissolved in the polymerization solvent. The adhesive composition used to form the adhesive layer can preferably be manufactured using the above-mentioned polymerization reaction solution.

[0091] During polymerization, known or conventional thermal polymerization initiators and photopolymerization initiators can be used, depending on the polymerization method and polymerization mode. Examples of thermal polymerization initiators include azo-based initiators, peroxide-based initiators, redox initiators based on combinations of peroxides and reducing agents, and substituted ethane initiators. Examples of photopolymerization initiators include α-ketool-based photoinitiators, acetophenone-based photoinitiators, benzoin ether-based photoinitiators, ketal-based photoinitiators, aromatic sulfonyl chloride-based photoinitiators, photoactive oxime-based photoinitiators, benzophenone-based photoinitiators, thioxanone-based photoinitiators, and acylphosphine oxide-based photoinitiators. One polymerization initiator can be used alone or in appropriate combinations of two or more.

[0092] The amount of polymerization initiator used is the usual amount, for example, it can be selected from about 0.005 to 1 part by weight (typically 0.01 to 1 part by weight) relative to 100 parts by weight of all monomer raw materials.

[0093] In the above polymerization, various known chain transfer agents (which can also be understood as molecular weight regulators or degree of polymerization regulators) can be used as needed. Thiols such as n-dodecyl mercaptan, tert-dodecyl mercaptan, mercaptoacetic acid, and α-thioglycerol can be used as chain transfer agents. Alternatively, chain transfer agents that do not contain sulfur atoms (non-sulfur chain transfer agents) can be used. Specific examples of non-sulfur chain transfer agents include anilines such as N,N-dimethylaniline and N,N-diethylaniline; terpenoids such as α-pinene and terpinolene; styrene compounds such as α-methylstyrene and α-methylstyrene dimer; compounds containing benzylidene groups such as dibenzylideneacetone, cinnamyl alcohol, and cinnamaldehyde; hydroquinones such as hydroquinone and naphthol; quinones such as benzoquinone and naphthoquinone; alkenes such as 2,3-dimethyl-2-butene and 1,5-cyclooctadiene; alcohols such as phenol, benzyl alcohol, and allyl alcohol; benzyl hydrogen compounds such as diphenylbenzene and triphenylbenzene; and so on.

[0094] Chain transfer agents can be used alone or in combination of two or more. When using chain transfer agents, the amount used can be, for example, about 0.01 to 1 part by weight relative to 100 parts by weight of the monomer raw material. The technology disclosed in this specification can also preferably be implemented without the use of chain transfer agents.

[0095] There are no particular limitations on the molecular weight of acrylic polymers; it can be set to an appropriate range according to the required performance. The weight-average molecular weight (Mw) of acrylic polymers is typically about 10 × 10⁻⁶. 4 Above (e.g., 20×10) 4 From the perspective of achieving both good balance and cohesion, a value greater than 30 × 10 is suitable (as mentioned above). 4 Preferably about 40×10 4 The above can be approximately 50×10 4 The above can be approximately 55 × 10 4 That's all. There is no particular upper limit to the Mw of acrylic polymers. From the viewpoint of the coatability of the adhesive composition, the Mw of acrylic polymers is generally suitable to be about 500 × 10⁻⁶. 4 For example, it could be approximately 150×10 4 The following can be approximately 75×10 4 The above Mw can be the Mw of an acrylic polymer in either the adhesive composition or the adhesive layer.

[0096] The term Mw here refers to the value obtained using gel permeation chromatography (GPC) converted to standard polystyrene. For example, a GPC apparatus such as the "HLC-8320GPC" (column: TSKgelGMH-H(S), manufactured by Tosoh Corporation) can be used. The same applies to the examples described later.

[0097] The acrylic adhesive layer may, as needed, further include polymers other than acrylic polymers as by-polymers. Examples of such by-polymers include polymers other than acrylic polymers from various polymers that can be included in the adhesive layer. When the adhesive layer disclosed in this specification is an acrylic adhesive layer that includes not only an acrylic polymer but also by-polymers, the content of the by-polymer is preferably less than 100 parts by weight relative to 100 parts by weight of the acrylic polymer, preferably 50 parts by weight or less, more preferably 30 parts by weight or less, and even more preferably 10 parts by weight or less. The content of the by-polymer may be 5 parts by weight or less, or even 1 part by weight or less, relative to 100 parts by weight of the acrylic polymer. The technology disclosed in this specification can preferably be implemented, for example, by having 99.5% to 100% by weight of the polymer included in the adhesive layer be an acrylic polymer.

[0098] (Adhesive layers other than acrylic)

[0099] The adhesive layer constituting the adhesive surface in the adhesive sheet disclosed in this specification may be an adhesive layer with a polymer other than an acrylic polymer as the base polymer, i.e., an adhesive layer other than an acrylic polymer. For adhesive layers other than acrylic polymers, in addition to the base polymer, by-product polymers other than the base polymer may be further included as needed. In this case, the content of the by-product polymers in the adhesive layer other than acrylic polymers may be selected from the contents exemplified above as the content of by-product polymers in acrylic adhesive layers. Adhesive layers other than acrylic polymers may be adhesive layers containing acrylic polymers as by-product polymers.

[0100] (Glass transition temperature)

[0101] The glass transition temperature (Tg) of the base polymer (e.g., an acrylic polymer) constituting the adhesive layer is preferably about 15°C or lower. In some embodiments, from the viewpoint of adhesion to the adherends (e.g., conformity to the surface shape of the adherends), the aforementioned Tg is suitable to be 10°C or lower, preferably 0°C or lower, and can be -10°C or lower, -20°C or lower, -30°C or lower, or -40°C or lower. Furthermore, from the viewpoint of adhesive cohesiveness and ease of light peeling based on water stripping, the Tg of the base polymer can be, for example, -75°C or higher, -60°C or higher, or -55°C or higher.

[0102] Here, in this specification, the glass transition temperature (Tg) of a polymer refers to the glass transition temperature calculated using the Fox formula based on the composition of the monomer raw materials constituting the polymer. The aforementioned Fox formula, as shown below, is a formula relating the Tg of the copolymer to the glass transition temperature (Tgi) of the homopolymer obtained by homopolymerizing the monomers constituting the copolymer.

[0103] 1 / Tg=Σ(Wi / Tgi)

[0104] It should be noted that in the above Fox formula, Tg represents the glass transition temperature of the copolymer (unit: K), Wi represents the weight fraction of monomer i in the copolymer (weight-based copolymerization ratio), and Tgi represents the glass transition temperature of the homopolymer of monomer i (unit: K).

[0105] The glass transition temperature of the homopolymer used in the calculation of Tg is the value recorded in known sources. For example, for the monomers listed below, the following values ​​are used as the glass transition temperatures of the homopolymers of those monomers.

[0106]

[0107] For the glass transition temperatures of homopolymers of monomers other than those listed above, the values ​​described in the "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) are used. In cases where multiple values ​​are described in this literature, the highest value is adopted.

[0108] Regarding the monomer whose glass transition temperature of the homopolymer is not recorded in the aforementioned Polymer Handbook, the value obtained using the following determination method was used (see Japanese Patent Application Publication No. 2007-51271). Specifically, 100 parts by weight of monomer, 0.2 parts by weight of azobisisobutyronitrile, and 200 parts by weight of ethyl acetate as the polymerization solvent were added to a reactor equipped with a thermometer, stirrer, nitrogen inlet pipe, and reflux condenser, and stirred for 1 hour while passing nitrogen gas through. The oxygen in the polymerization system was removed by operating as described above, and then the temperature was raised to 63°C and the reaction was carried out for 10 hours. Next, it was cooled to room temperature to obtain a homopolymer solution with a solid content concentration of 33% by weight. Next, the homopolymer solution was cast onto a release liner, dried, and a test sample (sheet-shaped homopolymer) with a thickness of approximately 2 mm was prepared. The test sample was punched into a disc shape with a diameter of 7.9 mm, clamped with parallel plates, and viscoelasticity was measured in shear mode using a viscoelasticity testing machine (ARES, manufactured by Rheometrics Inc.) while providing shear strain at a frequency of 1 Hz, under conditions of -70 to 150 °C and a heating rate of 5 °C / min. The peak temperature of tanδ was taken as the Tg of the homopolymer.

[0109] (Compound A)

[0110] As needed, a heat-resistant release agent may be included in the adhesive layer. As a heat-resistant release agent, at least one compound A selected from the group consisting of surfactants and compounds having a polyoxyalkylene backbone can be used. By including the aforementioned heat-resistant release agent in the adhesive layer, the effect of suppressing the increase in peel force of the adhesive sheet due to exposure to high temperatures can be achieved. For example, by including a heat-resistant release agent in the adhesive layer, the conventional peel force Fd can be reduced. a 、Fd b and water peeling force Fw a 、Fw b At least one of the properties decreases. While not a particularly limiting explanation, the reason for this effect can be considered as follows: Generally, as adhesion between the adhered material and the adhesive layer progresses through high-temperature exposure, the peel force may increase. However, the presence of a heat-resistant release agent on the adhesive layer surface can suppress this increase in peel force. Surfactants and compounds with a polyoxyalkylene backbone, which can be used as such heat-resistant release agents, both possess hydrophilic regions, thus tending to be present moderately on the adhesive layer surface, effectively suppressing the increase in peel force. Furthermore, as mentioned above, heat-resistant release agents possess hydrophilic regions and tend to be present moderately on the adhesive layer surface, thus also functioning as water-based release additives that facilitate gentle peeling based on water.

[0111] As surfactants and compounds having a polyoxyalkylene backbone, one or more known surfactants and compounds having a polyoxyalkylene backbone can be used without particular limitation. Compound A is typically preferably contained in the adhesive layer in a free form. It should be noted that the above-mentioned surfactants include compounds having a polyoxyalkylene backbone, which is self-evident, and vice versa.

[0112] As a surfactant that can be used as compound A, known nonionic surfactants, anionic surfactants, cationic surfactants, etc., can be used. Among them, nonionic surfactants are preferred. One surfactant can be used alone or two or more surfactants can be used in combination.

[0113] Examples of nonionic surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkylphenyl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether; polyoxyethylene fatty acid esters such as polyoxyethylene monolaurate, polyoxyethylene monostearate, and polyoxyethylene monooleate; and sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, and sorbitan monostearate. Sorbitan fatty acid esters such as sorbitan monooleate; polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan triisostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, etc.; polyoxyethylene glycerol ether fatty acid esters; polyoxyethylene-polyoxypropylene block copolymers; etc. Nonionic surfactants can be reactive surfactants with free radical polymerizable functional groups such as propenyl, (meth)allyl, vinyl, and (meth)acryloyl groups (e.g., nonionic reactive surfactants such as polyoxyethylene nonylpropenyl phenyl ether). These nonionic surfactants can be used alone or in combination of two or more. From the viewpoint of properly leveraging the effect of compound A being moderately predominantly present on the surface of the adhesive layer and improving the performance stability of the adhesive sheet, it is preferable to use a (non-reactive) nonionic surfactant that does not have such free radical polymerizable functional groups as described above.

[0114] Examples of anionic surfactants include alkylbenzene sulfonates such as nonylbenzene sulfonate and dodecylbenzene sulfonate (e.g., sodium dodecylbenzene sulfonate); alkyl sulfates such as lauryl sulfate (e.g., sodium lauryl sulfate, ammonium lauryl sulfate), and octadecyl sulfate; fatty acid salts; polyoxyethylene alkyl ether sulfates such as polyoxyethylene octadecyl ether sulfate and polyoxyethylene lauryl ether sulfate (e.g., sodium polyoxyethylene alkyl ether sulfate), and polyoxyethylene alkylphenyl ether sulfates such as polyoxyethylene lauryl ether sulfate (e.g., sodium polyoxyethylene alkyl ether sulfate), and polyoxyethylene alkylphenyl ether sulfate (e.g., sodium polyoxyethylene alkyl ether sulfate). Polyoxyethylene alkylphenyl ether ammonium sulfate, polyoxyethylene alkylphenyl ether sodium sulfate, etc.; polyoxyethylene styrene phenyl ether sulfate and other polyether sulfates; polyoxyethylene stearyl ether phosphate, polyoxyethylene lauryl ether phosphate and other polyoxyethylene alkyl ether phosphates; sodium salts, potassium salts and other polyoxyethylene alkyl ether phosphate salts of the above polyoxyethylene alkyl ether phosphates; lauryl sulfosuccinate, polyoxyethylene lauryl sulfosuccinate (e.g., sodium polyoxyethylene alkyl sulfosuccinate) and other sulfosuccinates; polyoxyethylene alkyl ether acetates; etc. When anionic surfactants form salts, the salts can be, for example, metal salts (preferably monovalent metal salts) such as sodium salts, potassium salts, calcium salts, magnesium salts, ammonium salts, amine salts, etc. Anionic surfactants can be used alone or in combination of two or more. From the same viewpoint as nonionic surfactants, non-reactive anionic surfactants are preferred.

[0115] Examples of cationic surfactants include polyoxyethylene laurylamine and polyoxyethylene stearylamine, among other polyether amines. Cationic surfactants can be used alone or in combination of two or more.

[0116] Compounds with a polyoxyalkylene backbone that can be used as compound A include, for example, polyethylene glycol (PEG), polypropylene glycol (PPG), and other polyalkylene glycols; polyethers containing polyoxyethylene units, polyethers containing polyoxypropylene units, compounds containing oxyethylene units and oxypropylene units (these units can be arranged randomly or in a block configuration); their derivatives; and so on. Additionally, compounds with a polyoxyalkylene backbone from the aforementioned nonionic, anionic, and cationic surfactants can also be used. They can be used alone or in combination of two or more. Among these, compounds containing a polyoxyethylene backbone (also called polyoxyethylene segments) are preferred, and PEG is more preferred.

[0117] There is no particular limitation on the molecular weight (chemical weight) of compounds having a polyoxyalkylene backbone (e.g., polyethylene glycol). From the viewpoint of uniform mixing, it is suitable, for example, to be less than 1000, preferably about 600 or less (e.g., 500 or less). There is no particular limitation on the lower limit of the molecular weight of compounds having a polyoxyalkylene backbone (e.g., polyethylene glycol), but compounds with a molecular weight of about 100 or more (e.g., about 200 or more, and further about 300 or more) are preferred.

[0118] An adhesive layer containing compound A can typically be formed from an adhesive composition containing compound A. The adhesive composition containing compound A is preferably prepared by a method including adding compound A in a solvent-free form or in the form of an organic solvent solution. The term "solvent-free form" refers to a form that is not diluted by an organic solvent or water that does not form an adhesive layer, such as a form formed from compound A. The organic solvent used in the preparation of the organic solvent solution can be appropriately selected from existing known organic solvents. Specific examples of the organic solvent mentioned above include the same solvent used in the solution polymerization described later. Preferred examples include ethyl acetate, mixed solvents containing ethyl acetate (which may be a mixture of ethyl acetate and toluene), toluene, and mixed solvents containing toluene. For example, ethyl acetate or a mixed solvent with ethyl acetate as the main component is preferably used. For solvent-based or active energy ray-cured adhesive compositions, from the viewpoint of preventing the introduction of water into the adhesive composition, in some ways, it is preferable to add compound A in the form of a substantially water-free organic solvent solution (e.g., the water content is less than 10 parts by weight, less than 5 parts by weight, or less than 1 part by weight relative to 100 parts by weight of compound A). This results in the formation of an adhesive layer with higher uniformity.

[0119] In some approaches, nonionic compounds, such as compound A, are preferred for their ease of uniform incorporation into the adhesive composition. With an adhesive composition incorporating compound A in good uniformity, there is a tendency to form an adhesive layer in which compound A is uniformly present on the surface. This is preferable from the viewpoint of facilitating smoother peeling of the adhesive sheet from the adhered object and reducing the load on the adhered object due to variations in peel force (e.g., vibration or impact accompanying such variations).

[0120] There are no particular limitations on the HLB of compound A. The HLB of compound A can be, for example, 1 or more, or 3 or more. The HLB of compound A is preferably 5 or more, and can be 6 or more, 8 or more, or 9 or more. This tends to result in suitable water-stripping properties. The HLB of compound A is more preferably 10 or more, further preferably 11 or more, even more preferably 12 or more, particularly preferably 13 or more, can be 14 or more, 15 or more, and even more than 16. With compound A having an HLB within the above range, light water-stripping properties can be more effectively exhibited. The upper limit of the above HLB is 20 or less, for example, 18 or less. In some embodiments, for example from a compatibility viewpoint, the HLB of compound A can be 16 or less, for example, 15 or less.

[0121] It should be noted that HLB in this specification refers to the hydrophilic-lipophilic balance (HLB) proposed by Griffin, which is a value representing the degree of affinity of a surfactant for water and oil, expressed as a ratio of hydrophilicity to lipophilicity between 0 and 20. The definition of HLB is as described in W.G. Griffin: J. Soc. Cosmetic Chemists, 1, 311 (1949), and in "Surfactant Handbook," 3rd edition, published by Kogaku Toshosha, November 25, 1972, pp. 179-182, co-authored by Takahashi Koshimitsu, Naniwa Yoshiro, Koike Motoo, and Kobayashi Masao. Compound A having the above HLB can be selected based on the above references and the technical knowledge of those skilled in the art.

[0122] In some embodiments, compound A, from the viewpoint of affinity with aqueous stripping liquid, is preferably a compound having two or more hydroxyl groups per molecule, and more preferably a compound having three or more hydroxyl groups per molecule. Examples of compound A having two or three or more hydroxyl groups per molecule include sorbitan monoester, polyoxyalkylene sorbitan monoester, polyoxyalkylene glycerol ether, polyoxyalkylene diglycerol ether, and polyoxyalkylene glycerol ether monoester. There is no particular upper limit to the number of hydroxyl groups in compound A per molecule; from the viewpoint of solubility in organic solvents and ease of preparation of the adhesive composition, it is generally suitable to have 10 or less, preferably 8 or less, and can be 6 or less, or 4 or less.

[0123] In some approaches, from the viewpoint of solubility in organic solvents (e.g., esters such as ethyl acetate), a nonionic compound having a fatty acid ester structure is preferred as compound A. Compound A having a fatty acid ester structure also becomes advantageous in terms of compatibility within the adhesive layer. For example, compound A having a fatty acid ester structure is preferred as compound A contained in an acrylic adhesive layer. Examples of nonionic compounds having a fatty acid ester structure include sorbitan fatty acid esters, polyoxyalkylene fatty acid esters, and polyoxyalkylene fatty acid monoesters.

[0124] In some methods, as compound A, from the viewpoint of ease of preparation of organic solvent solution, it is preferred that it be in liquid state at room temperature (25°C) in the form of 100% solid component.

[0125] In some methods, compound A is preferably a compound that dissolves without phase separation in Test II below, and more preferably a compound that dissolves without phase separation in Test I below. It should be noted that in Tests I and II below, compound A is used in 100% solid form and is carried out at room temperature (23-25°C).

[0126] [Experiment I]

[0127] Place 90g of ethyl acetate and 10g of compound A into a 200ml container, stir with a glass rod for 1 minute, then let stand. After 5 minutes, observe visually whether phase separation has occurred.

[0128] [Experiment II]

[0129] 90g of ethyl acetate and 10g of compound A were placed in a 200mL container and stirred with a glass rod for 1 minute. Then, the mixture was treated with an ultrasonic disperser at 35kHz for 10 minutes, stirred with a glass rod for another minute, and then allowed to stand. After 5 minutes, the presence or absence of phase separation was observed visually.

[0130] It should be noted that, as an ultrasonic dispersion device, the "ULTRASONIC CLEANER" machine model manufactured by AS ONE or an equivalent device can be used.

[0131] There is no particular limitation on the amount of compound A used, and it can be set in a way that appropriately exerts the effect corresponding to the purpose (e.g., the effect of suppressing the increase in peel force due to exposure to high temperature, and the effect of facilitating light peeling based on water peeling, or both). In some embodiments, the amount of compound A used, relative to 100 parts by weight of the base polymer, can be, for example, about 5 parts by weight or less. From the viewpoint of the bonding reliability and water resistance reliability of the adhered objects in the stage where peeling is not desired, it is suitable to be about 3 parts by weight or less, preferably less than 2 parts by weight, more preferably less than 1 part by weight, less than 0.8 parts by weight, less than 0.6 parts by weight, less than 0.4 parts by weight, less than 0.2 parts by weight, or less than 0.1 parts by weight. For compound A with a high HLB (e.g., 5 or more, preferably 10 or more), there is a tendency to easily exert good water peeling properties even when added in small amounts. Furthermore, the amount of compound A relative to 100 parts by weight of the base polymer can be, for example, 0.001 parts by weight or more. From the viewpoint of ensuring that compound A is uniformly present on the surface of the adhesive layer and that the adhesive sheet can be peeled off from the adhered object more smoothly, it is generally suitable to be 0.01 parts by weight or more, preferably 0.03 parts by weight or more (e.g., 0.1 parts by weight or more). In compositions where water-repellent properties are important, the amount of compound A relative to 100 parts by weight of the base polymer can be 0.3 parts by weight or more (e.g., 0.5 parts by weight or more).

[0132] (Cross-linking agent)

[0133] In the adhesive layer, a crosslinking agent may be used as needed for purposes such as adjusting cohesion. The crosslinking agent may be included in the adhesive layer in its post-crosslinking form or in its pre-crosslinking form. There are no particular limitations on the type of crosslinking agent; for example, it can be selected from known crosslinking agents based on the composition of the adhesive composition and in a manner that allows the crosslinking agent to perform its appropriate crosslinking function within the adhesive layer. Examples of usable crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, carbodiimide-based crosslinking agents, melamine-based crosslinking agents, urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, hydrazine-based crosslinking agents, and amine-based crosslinking agents. They can be used alone or in combination of two or more. In some preferred embodiments, at least an isocyanate-based crosslinking agent is used as the crosslinking agent. Isocyanate-based crosslinking agents can be used in combination with other crosslinking agents (e.g., epoxy-based crosslinking agents).

[0134] As isocyanate-based crosslinking agents, multifunctional isocyanate compounds with two or more functions can be used. Examples include aromatic isocyanates such as toluene diisocyanate, xylene diisocyanate, polymethylene polyphenyl diisocyanate, tris(p-isocyanatophenyl) thiophosphate, and diphenylmethane diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; and aliphatic isocyanates such as 1,6-hexanediisocyanate; etc. Commercially available examples include trimethylolpropane / toluene diisocyanate trimer adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), trimethylolpropane / 1,6-hexanediisocyanate trimer adduct (manufactured by Tosoh Corporation, trade name "Coronate HL"), and isocyanurate derivatives of 1,6-hexanediisocyanate (manufactured by Tosoh Corporation, trade name "Coronate HX"), etc.

[0135] As epoxy crosslinking agents, epoxy crosslinking agents having two or more epoxy groups per molecule can be used without particular limitation. Epoxy crosslinking agents having three to five epoxy groups per molecule are preferred. Specific examples of epoxy crosslinking agents include N,N,N',N'-tetraglycidyl-m-phenylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, and polyglycerol polyglycidyl ether. Commercially available epoxy crosslinking agents include those manufactured by Mitsubishi Gas Chemical Co., Ltd. under the trade names "TETRAD-X" and "TETRAD-C", manufactured by DIC under the trade name "EPICLON CR-5L", manufactured by Nagase ChemteX Corporation under the trade name "Denacol EX-512", and manufactured by Nissan Chemical Industries Co., Ltd. under the trade name "TEPIC-G".

[0136] As an oxazoline crosslinking agent, oxazoline crosslinking agents having more than one oxazoline group per molecule can be used without particular restrictions.

[0137] Examples of aziridine-based crosslinking agents include trimethylolpropane tris[3-(1-aziridine)propionate] and trimethylolpropane tris[3-(1-(2-methyl)aziridine propionate)].

[0138] As a carbodiimide-based crosslinking agent, low-molecular-weight compounds or high-molecular-weight compounds having two or more carbodiimide groups can be used.

[0139] Metal chelate crosslinking agents are typically substances having a structure formed by covalent or coordinate bonding of a multivalent metal with an organic compound. Examples of such multivalent metal atoms include Al, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Ba, Mo, La, Sn, and Ti. Al, Zr, and Ti are preferred. Examples of such organic compounds include alkyl esters, alcohols, carboxylic acids, ethers, and ketones. Metal chelate crosslinking agents are typically compounds in which the oxygen atom of the organic compound is bonded (covalently or coordinately) to the aforementioned multivalent metal.

[0140] In some methods, peroxides can be used as crosslinking agents. Examples of peroxides include di(2-ethylhexyl) peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, disec-butyl peroxydicarbonate, tert-butyl peroxyneodecanate, tert-hexyl peroxyneopentate, tert-butyl peroxyneopentate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutyl peroxyisobutyrate, and benzoyl peroxide. Among these, di(4-tert-butylcyclohexyl) peroxydicarbonate, dilauroyl peroxide, and benzoyl peroxide are examples of peroxides with particularly excellent crosslinking reaction efficiency. It should be noted that when using peroxides as the above-mentioned polymerization initiators, the peroxide residues that were not used in the polymerization reaction can also be used in the crosslinking reaction. In this case, the residual amount of peroxide is quantified, and if the proportion of peroxide does not meet the specified amount, peroxide is added as needed to reach the specified amount. The quantification of peroxides can be performed using the method described in Japanese Patent No. 4971517.

[0141] There is no particular limitation on the amount of crosslinking agent used (the total amount of both when using two or more crosslinking agents), and it can be appropriately set in a way that achieves the desired effect. From the viewpoint of preventing residue and suppressing the increase in peel force due to high-temperature exposure after application, the amount of crosslinking agent used relative to 100 parts by weight of the base polymer (e.g., acrylic polymer) is generally suitable to be about 0.01 parts by weight or more, preferably about 0.1 parts by weight or more, more preferably about 0.5 parts by weight or more, and can be about 1.0 parts by weight or more, about 1.5 parts by weight or more, or about 2.0 parts by weight or more.

[0142] Furthermore, the amount of crosslinking agent used relative to 100 parts by weight of the base polymer is generally suitable to be about 15 parts by weight or less. From the viewpoint of adhesion and bonding reliability relative to the adhered objects during semiconductor processing, it is preferably about 12 parts by weight or less, and more preferably about 10 parts by weight or less. In some methods that place greater emphasis on the initial conventional peel strength Fd0, the amount of crosslinking agent used relative to 100 parts by weight of the base polymer can be, for example, less than 7.0 parts by weight, less than 5.0 parts by weight, less than 4.0 parts by weight, or less than 3.0 parts by weight. In methods that include a certain amount (e.g., more than 0.2 parts by weight relative to 100 parts by weight of the base polymer) of compound A, it is also advantageous from the viewpoint of suppressing the decrease in the initial conventional peel strength Fd0 caused by excessive presence of compound A on the surface of the adhesive layer, provided that the amount of crosslinking agent used is not excessive.

[0143] In the use of isocyanate-based crosslinking agents as crosslinking agents, from the viewpoint of preventing residual adhesive and suppressing the increase in peel force caused by high temperature exposure after application, the amount of isocyanate-based crosslinking agent used relative to 100 parts by weight of the base polymer is generally suitable to be about 0.1 parts by weight or more, preferably about 0.5 parts by weight or more, more preferably about 0.7 parts by weight or more, and can be about 1.0 parts by weight or more, or about 1.5 parts by weight or more.

[0144] In addition, the amount of isocyanate-based crosslinking agent used relative to 100 parts by weight of the base polymer is generally suitable to be about 15 parts by weight or less. From the viewpoint of the adhesion and bonding reliability of the adhered objects during semiconductor processing, it is preferably about 12 parts by weight or less, more preferably about 10 parts by weight or less, and can be less than 7.0 parts by weight, less than 5.0 parts by weight, less than 4.0 parts by weight, less than 3.0 parts by weight, or less than 2.5 parts by weight.

[0145] In the use of an epoxy crosslinking agent (which may involve the combined use of an isocyanate crosslinking agent and an epoxy crosslinking agent), from the viewpoint of suppressing the increase in peel force due to high-temperature exposure after adhesion, the amount of epoxy crosslinking agent used relative to 100 parts by weight of the base polymer is typically suitable to be about 0.01 parts by weight or more, preferably about 0.05 parts by weight or more, more preferably about 0.1 parts by weight or more, and may be about 0.3 parts by weight or more, or about 0.5 parts by weight or more. In a preferred embodiment, the amount of epoxy crosslinking agent used relative to 100 parts by weight of the base polymer may, for example, be greater than 0.5 parts by weight, and may be 0.6 parts by weight or more.

[0146] Furthermore, from the viewpoint of adhesion and bonding reliability relative to the adhered object during semiconductor processing, the amount of epoxy crosslinking agent used relative to 100 parts by weight of the base polymer is generally suitable to be about 5 parts by weight or less, preferably about 3 parts by weight or less, more preferably about 2 parts by weight or less, and can be 1.5 parts by weight or less, or 1.0 parts by weight or less.

[0147] When using both isocyanate-based and epoxy-based crosslinking agents, the amount of epoxy-based crosslinking agent used, W EPO relative to the amount of isocyanate-based crosslinking agent used W NCO The ratio (weight ratio W) EPO :W NCO For example, it can be 0.005:1 or higher and 2:1 or lower, usually suitable is 0.01:1 or higher and 1:1 or lower, preferably greater than 0.10:1 and 0.80:1 or lower, more preferably greater than 0.25:1 and 0.60:1 or lower (for example, 0.30:1 or higher and 0.50:1 or lower).

[0148] To make the crosslinking reaction proceed more efficiently, a crosslinking catalyst can be used. Examples of crosslinking catalysts include tetrabutyl titanate, tetraisopropyl titanate, iron acetylacetone, butyltin oxide, and dioctyltin dilaurate, among other metal-based crosslinking catalysts. Tin-based crosslinking catalysts, such as dioctyltin dilaurate, are preferred. There is no particular limitation on the amount of crosslinking catalyst used. The amount of crosslinking catalyst used relative to 100 parts by weight of the base polymer can be, for example, about 0.0001 parts by weight or more and 1 part by weight, 0.001 parts by weight or more and 0.1 parts by weight, or 0.005 parts by weight or more and 0.5 parts by weight or less.

[0149] (Other optional ingredients)

[0150] The adhesive layer may, as needed, contain tackifying resins (e.g., rosin-based, petroleum-based, terpene-based, phenolic, ketone-based, etc.), viscosity modifiers (e.g., tackifiers), leveling agents, plasticizers, fillers, colorants such as pigments and dyes, stabilizers, preservatives, antioxidants, anti-aging agents, and various other additives conventional in the field of adhesives as optional components. Such additives can be obtained using existing known additives through conventional methods; detailed descriptions are omitted as these are not substances that particularly characterize the present invention.

[0151] From the viewpoint of simultaneously achieving a good balance between adhesion to the adhered material during semiconductor processing and peelability (e.g., peelability based on water peeling) when removing the adhered material, in some methods, the content of the adhesive resin in the adhesive layer is, for example, less than 5 parts by weight, and further less than 3 parts by weight, less than 1 part by weight, less than 0.5 parts by weight, or less than 0.1 parts by weight, relative to 100 parts by weight of the base polymer. It can be an adhesive layer that substantially does not contain the adhesive resin (e.g., the content of the adhesive layer relative to 100 parts by weight of the base polymer is 0 to 0.05 parts by weight).

[0152] In some preferred embodiments, the adhesive layer may contain a polymer (typically a base polymer) comprising approximately 80% by weight or more of the total weight of the adhesive layer. This ideally achieves the effect of reduced peel force when water is applied for peeling (a gentler peeling effect). From this perspective, the polymer content is preferably approximately 85% by weight or more of the total weight of the adhesive layer, more preferably approximately 90% by weight or more, approximately 92% by weight or more, approximately 95% by weight or more, or approximately 98% by weight or more.

[0153] In some other embodiments of the adhesive sheet disclosed in this specification, the adhesive sheet may have an adhesive surface composed of an adhesive layer having active energy radiation (preferably ultraviolet) curability, i.e., an active energy radiation curable adhesive layer. The aforementioned active energy radiation curable adhesive layer may, for example, be an adhesive layer based on an active energy radiation curable polymer (e.g., an acrylic polymer) containing curable functional groups at at least one position in the side chain, main chain, and main chain end. Other examples of active energy radiation curable adhesive layers include adhesive layers containing monomers or oligomers having two or more curable functional groups within the molecule. Examples of the polymers, monomers, and oligomers that can be used to make the adhesive layer curable by active energy radiation include polymers having functional groups with carbon-carbon double bonds in the side chains (e.g., (meth)acryloyl, vinyl, etc.), polyfunctional (meth)acrylates (e.g., trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, etc.), isocyanate compounds having carbon-carbon double bonds (e.g., ethyl 2-isocyanate (meth)acrylate, m-isopropenyl-α,α-dimethylbenzyl isocyanate, etc.), urethane oligomers, urethane (meth)acrylates, etc., but not limited to these. Known photoinitiators may be included in the active energy radiation curable adhesive layer as needed.

[0154] The adhesive sheet disclosed in this specification preferably has an adhesive surface composed of an adhesive layer that is not curable by active energy rays (an adhesive layer that is not curable by active energy rays). Adhesive sheets with an adhesive surface composed of an adhesive layer that is not curable by active energy rays exhibit good performance stability relative to irradiation by active energy rays (such as ultraviolet rays), and are also preferably used in semiconductor processing methods that include irradiation by active energy rays.

[0155] <Formation of Adhesive Layer>

[0156] The adhesive layer constituting the adhesive surface of the adhesive sheet disclosed in this specification can be an adhesive layer formed from an adhesive composition comprising a base polymer (e.g., an acrylic polymer) and, if necessary, other optional components. The adhesive composition can be in various forms, including: solvent-based adhesive compositions containing the adhesive (adhesive component) in an organic solvent; active energy radiation-cured adhesive compositions prepared by curing with active energy rays such as ultraviolet light or radiation to form an adhesive; water-dispersible adhesive compositions in which the adhesive is dispersed in water; hot-melt adhesive compositions that are applied in a molten state and form an adhesive upon cooling to near room temperature; and so on. It should be noted that the aforementioned active energy radiation-cured adhesive compositions are typically liquid compositions that exhibit a degree of fluidity suitable for application at room temperature (approximately 0°C to 40°C, for example, around 25°C) and are cured by irradiation with active energy rays to form an adhesive (viscoelastic).

[0157] Some methods involve adhesive sheets that have an adhesive layer formed using a solvent-based adhesive composition or an active energy radiation-curable adhesive composition. In the case where the adhesive layer contains compound A, a solvent-based adhesive composition is preferred from the viewpoint of ease of preparation of the adhesive composition containing compound A.

[0158] The adhesive layer of the adhesive sheet disclosed in this specification can be formed by applying an adhesive composition to a suitable surface (e.g., coating) and then appropriately performing a curing treatment (drying, crosslinking, etc.). If two or more curing treatments are performed, they can be performed simultaneously or in multiple steps. Multilayer adhesive layers with two or more layers can be fabricated by bonding pre-formed adhesive layers together. Alternatively, an adhesive composition can be applied to a pre-formed first adhesive layer and cured to form a second adhesive layer.

[0159] The coating of the adhesive composition can be carried out using conventional coating machines such as gravure roller coaters, reverse roller coaters, kiss roller coaters, dip roller coaters, bar coaters, doctor blade coaters, and spray coaters. For adhesive sheets having a support structure, as a method for forming an adhesive layer on the support, a direct method can be used to directly apply the adhesive composition to the support to form the adhesive layer, or a transfer method can be used to transfer the adhesive layer formed on the release surface to the support.

[0160] In the adhesive sheet disclosed in this specification, the thickness of the adhesive layer is not particularly limited and can be appropriately selected according to the purpose. Generally, the thickness of the adhesive layer is suitable to be about 5 to 200 μm. From the viewpoint of adhesion, it is preferably 10 μm or more, for example, about 15 μm or more, preferably 150 μm or less, more preferably 100 μm or less, and even more preferably about 80 μm or less, for example, 60 μm or less. From the viewpoint of easily suppressing the increase in peel force due to heating, in some embodiments, the thickness of the adhesive layer can be, for example, 40 μm or less, 30 μm or less, or 25 μm or less. In the case of a double-sided adhesive sheet in which adhesive layers are provided on both sides of a substrate, the thickness of each adhesive layer can be the same or different.

[0161] <Additional adhesive layer>

[0162] In some embodiments of the adhesive sheet disclosed in this specification, the adhesive sheet may be a structure in which an additional adhesive layer is laminated on the back side (the side opposite to the adhesive surface) of the adhesive layer constituting the adhesive surface. The adhesive layer constituting the adhesive surface and the additional adhesive layer are preferably laminated in direct contact. That is, it is preferable that there is no separator layer (e.g., a resin film such as a polyester film) completely separating the two adhesive layers between the adhesive layer constituting the adhesive surface and the additional adhesive layer. The additional adhesive layer may, for example, be an adhesive layer comprising one or more adhesives selected from various known adhesives such as acrylic adhesives, rubber adhesives (natural rubber, synthetic rubber, mixtures thereof, etc.), polysiloxane adhesives, polyester adhesives, urethane adhesives, polyether adhesives, polyamide adhesives, and fluorinated adhesives. From the viewpoint of transparency, weather resistance, etc., in some embodiments, acrylic adhesives are preferably used as the constituent material of the additional adhesive layer. Regarding other matters concerning the additional adhesive layer, the same configuration as the adhesive layer described above may be adopted, or an appropriate configuration may be adopted based on known or conventional techniques and common technical knowledge, depending on the application and purpose. Therefore, detailed descriptions are omitted here.

[0163] <Substrate>

[0164] In single-sided or double-sided adhesive sheets with a substrate, the substrate serving as the supporting (lining) adhesive layer can be various sheet-like substrates such as resin film, paper, cloth, rubber sheet, foam sheet, metal foil, or composites thereof. The aforementioned substrate can be a single layer or a laminate of the same or different substrates. It should be noted that, in this specification, a single layer refers to a layer formed from the same composition, including layers formed by stacking multiple layers of the same composition.

[0165] In a preferred embodiment, a substrate (resin film substrate) primarily composed of resin sheets can be used. Examples of resins constituting the substrate include, for instance, low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolymer polypropylene, polybutene, polymethylpentene, ethylene-vinyl acetate copolymer (EVA), ion-crosslinked polymers, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid (random, alternating) copolymers, ethylene-butene copolymers, ethylene-hexene copolymers, and other polyolefin resins; polyurethanes; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate, and polybutylene terephthalate (PBT); polycarbonate; polyimide; polyetheretherketone; polyetherimide; aromatic polyamides, fully aromatic polyamides, and other polyamides; polyphenylene sulfide; fluoropolymers; polyvinyl chloride; polyvinylidene chloride; cellulose resins; polysiloxane resins; and so on. The aforementioned resins can be used alone or in combination of two or more for the formation of the entire substrate or a portion thereof (e.g., any layer of a substrate with two or more laminated structures).

[0166] Depending on the requirements, various additives such as fillers (inorganic fillers, organic fillers, etc.), anti-aging agents, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, plasticizers, and colorants (pigments, dyes, etc.) can be added to the substrate.

[0167] The aforementioned substrate can be manufactured using any suitable method. For example, it can be manufactured using known methods such as calendering, casting, expansion extrusion, and T-die extrusion. Additionally, it can be manufactured by stretching treatment as needed.

[0168] To improve adhesion to and retention of the adhesive layer, physical treatments such as corona discharge, plasma treatment, sanding, ozone exposure, flame exposure, high-voltage electric shock exposure, and ionized radiation treatment can be applied to the adhesive layer side surface of the substrate; chemical treatments such as acid treatment, alkali treatment, and chromic acid treatment can be applied; and known or conventional surface treatments such as easy-to-bond treatment based on the coating agent (primer) can be used. Additionally, to impart antistatic properties, a conductive vapor-deposited layer containing metals, alloys, or their oxides can be formed on the substrate surface.

[0169] In some preferred embodiments, a primer layer may be provided on the adhesive layer side surface of the substrate. In other words, a primer layer may be disposed between the substrate and the adhesive layer. There are no particular limitations on the primer layer forming material; one or more of the following can be used: urethane (polyisocyanate) resins, polyester resins, acrylic resins, polyamide resins, melamine resins, olefin resins, polystyrene resins, epoxy resins, phenolic resins, isocyanurate resins, and polyvinyl acetate resins. When an acrylic or other adhesive layer is provided on a resin film substrate through a primer layer, polyester, urethane, or acrylic primer layers are preferred. When an acrylic adhesive layer is provided on a polyester substrate such as a PET film through a primer layer, a polyester primer layer is particularly preferred. The thickness of the primer layer is not particularly limited and is typically in the range of about 0.1 μm to 10 μm (e.g., 0.1 μm to 3 μm, typically 0.1 μm to 1 μm). The base coating can be formed using known or conventional coating machines such as gravure roller coating machines and reverse roller coating machines.

[0170] In the case of a single-sided adhesive sheet with an adhesive layer provided on one side of a substrate, the non-adhesive layer (back side) of the substrate can be peeled off using a release agent (back side treatment agent). There are no particular limitations on the back side treatment agent that can be used to form the back side treatment layer; known or conventional treatment agents such as polysiloxane-based, fluorine-based, and long-chain alkyl-based back side treatment agents can be used depending on the purpose and application.

[0171] The thickness of the substrate is not particularly limited and can be appropriately selected depending on the purpose; typically, it can be around 3μm to 800μm. From the viewpoint of the processability and operability of the adhesive sheet (e.g., ease of application and peeling from the adherend), a substrate thickness of 5μm or more is suitable, preferably 10μm or more. From the viewpoint of improving the protection of the adherend, 20μm or more is preferred, but 30μm or more, or 40μm or more, is also acceptable. In some cases where greater emphasis is placed on protection, the substrate thickness can be, for example, 55μm or more, 75μm or more, or 90μm or more. Furthermore, from the viewpoint of reducing the load on the adherend during peeling, a substrate thickness of 300μm is generally suitable, preferably 200μm or less, but can be 150μm or less, 125μm or less, 80μm or less, or 60μm or less.

[0172] The total thickness of the adhesive sheet (which may include an adhesive layer and a substrate, but excluding a release liner) disclosed in this specification is not particularly limited, but is suitable in the range of about 10 μm to 1000 μm. Considering adhesion and operability, the total thickness of the adhesive sheet is preferably in the range of about 15 μm to 300 μm, more preferably in the range of about 20 μm to 300 μm, and can be in the range of 20 μm to 200 μm. Furthermore, from the viewpoint of improving the protection of the adhered object, a total thickness of about 30 μm or more is advantageous, preferably about 40 μm or more, and more preferably about 50 μm or more (e.g., 60 μm or more). In some embodiments where greater emphasis is placed on protection, the total thickness of the adhesive sheet can be greater than 65 μm, greater than 80 μm, or greater than 100 μm.

[0173] <Adhesive Sheet>

[0174] (Initial conventional peel force Fd0)

[0175] The initial conventional peel force Fd0 of the adhesive sheet disclosed in this specification is preferably 0.10 N / 20 mm or more. This provides the adhesive sheet with appropriate adhesion for semiconductor processing, contributing to improved processability. For example, when the adhesive sheet disclosed in this specification is used as a back-grinding tape to protect the circuit-forming surface of a semiconductor wafer (adhesive) during the back-grinding process, peeling of the adhesive sheet and damage to the semiconductor wafer during back-grinding can be prevented. There is no particular upper limit to the initial conventional peel force Fd0. From the viewpoint of easily suppressing the peel force after heating below a specified value, it is generally suitable to be less than 1.00 N / 20 mm, more preferably 0.60 N / 20 mm or less, and can be 0.40 N / 20 mm or less, or 0.30 N / 20 mm or less. The initial conventional peel force Fd0 can be measured using the methods described above, and more specifically, the methods described in the embodiments described later. The initial conventional peel force Fd0 can be adjusted by the selection of the base polymer, the type and amount of compound A when using compound A, and the type and amount of crosslinking agent when using crosslinking agent.

[0176] (Conventional peel force Fd) a )

[0177] The conventional peel force Fd of the adhesive sheet disclosed in this specification aThe (normal peel force after heating to 150°C) is preferably 1.00 N / 20 mm or less. This prevents an increase in the load on the adherend during subsequent peeling, even when the adhesive sheet is exposed to high temperatures after being applied to the adherend. Further reduction of the load on the adherend can be achieved by using a water peeling method for peeling. In some embodiments, from the viewpoint of reducing the load on the adherend during peeling, the normal peel force after heating to 150°C is more preferably 0.60 N / 20 mm or less, and more preferably 0.40 N / 20 mm or less. There is no particular limitation on the lower limit of the normal peel force after heating to 150°C; from the viewpoint of achieving a balance between adhesion and bonding reliability relative to the adherend during processing, it can be, for example, 0.005 N / 20 mm or more, 0.01 N / 20 mm or more, or 0.02 N / 20 mm or more. The normal peel force after heating to 150°C can be measured using the methods described above, and more specifically, the methods described in the embodiments described later. The standard peel strength after heating to 150℃ can be adjusted by the selection of the base polymer, the type and amount of compound A when using compound A, and the type and amount of crosslinking agent when using crosslinking agent.

[0178] It should be noted that even with a standard peel force Fd a For adhesive sheets exceeding any of the above upper limits, if they are designed to be sufficiently lightly peeled off by water (e.g., if the water peeling force Fw...), a If the peel force is 0.40 N / 20 mm or less, more preferably 0.30 N / 20 mm or less, then the adhesive sheet can also be peeled off after heating using a water peeling method, thereby appropriately suppressing the load on the adhered object and the generation of residual adhesive. Therefore, in the above method, the conventional peel force Fd of the adhesive sheet is... a It can be greater than 1.00 N / 20 mm. The typical peel force Fd of the adhesive sheet in this method... a There are no special restrictions; for example, it can be below 2.00N / 20mm or below 1.00N / 20mm.

[0179] (Conventional peel force Fd) b )

[0180] The conventional peel force Fd of the adhesive sheet disclosed in this specification bThe (normal peel force after heating to 200°C) is preferably 3.00 N / 20 mm or less. This prevents an increase in the load on the adherend during subsequent peeling, even when exposed to higher temperatures under more severe conditions. By using a water-based peeling method to peel from the adherend, the load on the adherend during peeling can be further reduced. In some embodiments, from the viewpoint of reducing the load on the adherend during peeling, the normal peel force after heating to 200°C is more preferably 2.00 N / 20 mm or less, 1.50 N / 20 mm or less, 1.20 N / 20 mm or less, or 1.00 N / 20 mm or less. There is no particular limitation on the lower limit of the normal peel force after heating to 200°C; from the viewpoint of achieving a balance between the adhesion and bonding reliability relative to the adherend during processing, it can be, for example, 0.01 N / 20 mm or more, 0.02 N / 20 mm or more, or 0.03 N / 20 mm or more. The standard peel strength after heating to 200°C can be determined using the methods described above, and more specifically, the methods described in the examples below. The standard peel strength after heating to 200°C can be adjusted by the selection of the base polymer, the type and amount of compound A when using compound A, and the type and amount of crosslinking agent when using crosslinking agent.

[0181] It should be noted that even with a standard peel force Fd b For adhesive sheets exceeding any of the above upper limits, if they are designed to be sufficiently lightly peeled off by water (e.g., if the water peeling force Fw...), b If the peel force is 2.00 N / 20 mm or less, preferably 1.00 N / 20 mm or less, then the adhesive sheet can also be peeled off after heating using a water peeling method, thereby appropriately suppressing the load on the adhered object and the generation of residual adhesive. Therefore, in the above method, the conventional peel force Fd of the adhesive sheet is... b It can be greater than 3.00 N / 20 mm. The typical peel force Fd of the adhesive sheet in this method... b There are no special restrictions; for example, it can be below 5.00N / 20mm or below 4.00N / 20mm.

[0182] (water stripping force Fw) a )

[0183] The water peel strength Fw of the adhesive sheet disclosed in this specification aThe water peel force after heating to 150°C is preferably 0.30 N / 20 mm or less. Therefore, even if the adhesive sheet is exposed to high temperatures after being attached to the substrate, subsequent peeling using the water peel method can suppress the load on the substrate. In some embodiments, from the viewpoint of reducing the load on the substrate during peeling, the water peel force after heating to 150°C is more preferably less than 0.30 N / 20 mm, and even more preferably 0.25 N / 20 mm or less. There is no particular limitation on the lower limit of the water peel force after heating to 150°C; from the viewpoint of achieving a balance between adhesion and bonding reliability relative to the substrate during processing, it can be, for example, 0.01 N / 20 mm or more, 0.05 N / 20 mm or more, or 0.01 N / 20 mm or more. The water peel force after heating to 150°C can be measured using the methods described above, and more specifically, the methods described in the embodiments described later. The water peeling force after heating to 150℃ can be adjusted by selecting the base polymer, the type and amount of compound A when using compound A, and the type and amount of crosslinking agent when using crosslinking agent.

[0184] (water stripping force Fw) b )

[0185] The water peel strength Fw of the adhesive sheet disclosed in this specification b The water peel force after heating to 200°C is preferably 2.00 N / 20 mm or less. Therefore, even when exposed to higher temperatures under more severe conditions, subsequent peeling using the water peel method can suppress the load on the adhered material. In some embodiments, from the viewpoint of reducing the load on the adhered material during peeling, the water peel force after heating to 200°C can be 1.50 N / 20 mm or less, 1.00 N / 20 mm or less, 0.80 N / 20 mm or less, or 0.60 N / 20 mm or less. There is no particular limitation on the lower limit of the water peel force after heating to 200°C; from the viewpoint of achieving a balance between adhesion and bonding reliability relative to the adhered material during processing, it can be, for example, 0.05 N / 20 mm or more, 0.01 N / 20 mm or more, or 0.03 N / 20 mm or more. The water peel force after heating to 200°C can be measured using the methods described above, and more specifically, the methods described in the embodiments described later. The water peeling force after heating to 200℃ can be adjusted by the selection of the base polymer, the type and amount of compound A when using compound A, and the type and amount of crosslinking agent when using crosslinking agent.

[0186] (Conventional peel strength ratio Fd) b / Fd a )

[0187] For the adhesive sheet disclosed in this specification, the ratio of the conventional peel force [N / 20mm] after heating at 200°C to the conventional peel force [N / 20mm] after heating at 150°C (Fd) b / Fd a The conventional peel strength ratio is preferably 4.0 or less. This ensures that the adhesive sheet's peel strength after the high-temperature process is less affected by temperature unevenness that may occur during the process. For this adhesive sheet, when peeling it off from the substrate after a high-temperature process, the risk of adhesive residue is reduced, and the load on the substrate due to variations in peel strength is also reduced, which is therefore preferable. From the viewpoint of further reducing the impact of temperature unevenness, a conventional peel strength ratio of 3.5 or less is more preferable, and 3.0 or less is even more preferable. A conventional peel strength ratio is typically 1.0 or more.

[0188] (Conventional peel strength difference Fd) b -Fd a )

[0189] For the adhesive sheet disclosed in this specification, the difference between the conventional peel force [N / 20mm] after heating at 150°C and the conventional peel force [N / 20mm] after heating at 200°C (Fd) b -Fd a The defined conventional peel force difference is preferably 1.50 N / 20 mm or less. This ensures that the adhesive sheet's peel force after the high-temperature process is not easily affected by temperature unevenness that may occur during the process. For this adhesive sheet, when peeling it off from the substrate after a high-temperature process, the risk of residual adhesive is reduced, and the load on the substrate due to variations in peel force is also reduced, which is therefore preferable. From the viewpoint of further reducing the impact of temperature unevenness, the conventional peel force difference is more preferably 1.20 N / 20 mm or less, and can be 1.00 N / 20 mm or less, 0.80 N / 20 mm or less, or 0.60 N / 20 mm or less. After heating, the conventional peel force difference typically becomes 0 N / 20 mm or more, so there is no particular limitation on the lower limit; the closer it is to 0 N / 20 mm, the more preferred.

[0190] (Initial water stripping force Fw0)

[0191] The initial water peel force Fw0 of the adhesive sheet disclosed in this specification is preferably less than 0.10 N / 20 mm. Therefore, for the adhesive sheet, for example in semiconductor processing methods that do not involve high-temperature processes (e.g., high-temperature processes above 100°C, preferably above 60°C), water peeling can be used to appropriately reduce the load imposed on the adherend during peeling. Thus, for example, for adhesive sheets that can be used as back-grinding tapes, not only can damage to the semiconductor wafer that has been thinned by back-grinding be avoided, but the adhesive sheet can also be efficiently peeled from the semiconductor wafer. In some embodiments, the initial water peel force Fw0 is more preferably less than 0.09 N / 20 mm, can be less than 0.07 N / 20 mm, and can be less than 0.05 N / 20 mm. There is no particular limitation on the lower limit of the initial water peel force Fw0; from the viewpoint of reducing the load on the adherend, the smaller the value, the more advantageous it is. On the other hand, from the viewpoint of achieving a balance between the adhesion and bonding reliability relative to the adhered objects during processing, in some methods, the initial water peel force Fw0 can be, for example, 0.005 N / 20 mm or more, 0.01 N / 20 mm or more, 0.02 N / 20 mm or more, or 0.03 N / 20 mm or more. The initial water peel force Fw0 can be measured using the methods described above, and more specifically, the methods described in the examples described later. The initial water peel force Fw0 can be adjusted by the selection of the base polymer, the type and amount of compound A when using compound A, and the type and amount of crosslinking agent when using crosslinking agent, etc.

[0192] The tensile testing machine used for the above-mentioned conventional peel strength and water peel strength measurements can be the Shimadzu Autograph EZ-S precision universal testing machine or an equivalent device. During the measurement, if necessary, a suitable lining material (e.g., a PET film with a thickness of about 25 μm) can be attached to the adhesive sheet being tested to reinforce it.

[0193] It should be noted that in the embodiments described later, conventional peel force and water peel force were continuously measured for each test piece. However, different test pieces can also be used to measure conventional peel force and water peel force. For example, in cases where it is difficult to prepare test pieces of sufficient length to perform continuous measurements, different test pieces can be used for the measurement.

[0194] In some preferred embodiments of the adhesive sheet disclosed in this specification, the water peeling force Fw after heating at 200°C is... b [N / 20mm] Relative to the standard peel force Fd after heating at 200℃ bThe decrease rate of [N / 20mm] can be greater than 30%, for example. That is, the decrease rate of water peeling force after heating at 200°C, calculated using the following formula, is preferably 10% or more.

[0195] Water stripping force reduction rate after heating at 200℃ = 1 - (Fw) b / Fd b )

[0196] For adhesive sheets with a high rate of decrease in water peel strength after heating to 200°C, even if the peel strength increases due to heating after bonding, subsequent peeling using a water peel method can significantly reduce the peel strength compared to peeling using a conventional peel method, effectively reducing the load imposed on the adherends during peeling. In some preferred embodiments, the rate of decrease in water peel strength after heating to 200°C can be 15% or more, 25% or more, or 30% or more. There is no particular upper limit to the rate of decrease in water peel strength after heating to 200°C, which is typically below 100%, but from a practical point of view, it can be, for example, below 95% or below 90%.

[0197] <Uses>

[0198] The adhesive sheet disclosed in this specification can be used in the processing of various semiconductor wafers. These semiconductor wafers can be, for example, silicon wafers, silicon carbide (SiC) wafers, nitride semiconductor wafers (silicon nitride (SiN), gallium nitride (GaN), etc.), gallium arsenide wafers, and other compound semiconductor wafers. Regarding the adhesive sheet disclosed in this specification, in the process of manufacturing semiconductor devices (e.g., semiconductor chips) from such semiconductor wafers, it is typically preferred to use it as a semiconductor processing adhesive sheet for protecting and / or fixing the semiconductor wafer during processing, in cases where the semiconductor wafer has been bonded to the semiconductor wafer through preceding processes. Examples of processing that can be performed on the semiconductor wafer after the adhesive sheet disclosed in this specification is bonded and before the adhesive sheet is peeled off include back-grinding and dicing, but are not limited to these. It should be noted that in this specification, when the shape of the semiconductor wafer to be processed changes due to processing (e.g., overall or partial thinning based on back-grinding, single-wafer obtained by dicing, etc.), the processed article is sometimes still referred to as a semiconductor wafer.

[0199] The bonding of the adhesive sheet to the semiconductor wafer disclosed in this specification can be performed using any suitable method. The temperature for bonding the adhesive sheet can be around room temperature (e.g., 10°C to 35°C) or a temperature higher than room temperature (e.g., higher than 35°C, preferably 60°C to 90°C). Bonding the adhesive sheet at a temperature higher than room temperature is advantageous from the viewpoint of improving the adhesion between the adhesive sheet and the semiconductor wafer. After bonding the adhesive sheet within the room temperature range, a heat-pressurization process can be performed, applying a temperature higher than room temperature (e.g., 40°C to 90°C, preferably 40°C to 60°C) and a pressure higher than atmospheric pressure (e.g., 1.5 to 10 atm, preferably 3 to 7 atm). There is no particular limitation on the time for performing the above heat-pressurization process, and it can be set in a way that yields a suitable processing effect. In some methods, considering the stability of the processing effect and the balance of productivity, the time for performing the above heat-pressurization process can be set to 3 minutes to 1 hour (e.g., 5 minutes to 30 minutes).

[0200] For the adhesive sheet disclosed in this specification, by satisfying condition A above and at least one of conditions B to E, it can be well peeled from the substrate even when exposed to high temperatures during the period from application to peeling, for example, by suppressing residual adhesive and load on the substrate. Taking advantage of the above advantages, the adhesive sheet disclosed in this specification can preferably be used in a manner where a high-temperature process is performed after it is applied to the substrate and until it is peeled off from the substrate. Non-limiting examples of the high-temperature process include ion implantation for semiconductor wafers, ashing processes for removing resist, and annealing processes such as laser annealing. Such a high-temperature process can be performed, for example, with a semiconductor processing adhesive sheet (back-grinding tape) used in a back-grinding process attached, before and / or after the back-grinding process. Therefore, the adhesive sheet disclosed in this specification is preferably used as an adhesive sheet for semiconductor processing in a manner that includes a back-grinding process and a high-temperature process (which is performed before and / or after the back-grinding process) between the process of attaching to the substrate and the process of peeling off from the substrate.

[0201] The adhesive sheet disclosed in this specification can be peeled from the adhered object using conventional peeling methods (i.e., peeling methods without using water or other aqueous peeling solutions) or using an aqueous peeling method. From the viewpoint of improving peelability, the aqueous peeling method is preferred in some cases. The aqueous peeling solution used in the aqueous peeling method can be a liquid obtained by adding a small amount of additives to water or a water-based mixed solvent as needed. As a solvent other than water constituting the aforementioned mixed solvent, lower alcohols (e.g., ethanol), lower ketones (e.g., acetone), etc., that are homogeneous with water can be used. As the aforementioned additives, known surfactants, pH adjusters, etc., can be used. From the viewpoint of avoiding contamination of the adhered object, the aqueous peeling solution that is substantially free of additives is preferred in some cases. From an environmental hygiene viewpoint, water is particularly preferred as the aqueous peeling solution. There are no particular limitations on the type of water; considering the required purity and ease of access depending on the application, distilled water, ion-exchanged water, tap water, etc., can be used, for example.

[0202] <Semiconductor Device Manufacturing Methods>

[0203] The following describes one embodiment of a semiconductor device manufacturing method using the adhesive sheet disclosed in this specification. The semiconductor device manufacturing method of this embodiment includes the following steps: step (1), attaching the adhesive surface of the semiconductor processing adhesive sheet to the circuit forming surface side of a semiconductor wafer having a circuit forming surface; step (2), processing the semiconductor wafer with the adhesive sheet attached from the side opposite to the adhesive sheet; and step (3), peeling the adhesive sheet from the processed semiconductor wafer.

[0204] The above-described step (3) is preferably performed by supplying an aqueous stripping solution to the peeling front of the adhesive sheet as it is peeled from the processed semiconductor wafer (adhesive). This allows for gentle peeling of the adhesive sheet, thereby suppressing residual adhesive and reducing the load on the adhesive (processed semiconductor wafer). In some embodiments, the above-described step (3) may preferably be performed using the adhesive sheet peeling method described later.

[0205] Preferably, the high-temperature process described above is performed after step (1) and before step (3). Alternatively, an irradiation process with active energy rays (e.g., ultraviolet light) can be performed after step (1) and before step (3). The high-temperature process and the active energy irradiation process described above can each be performed in step (2), before step (2), or after step (2).

[0206] In some embodiments, step (2) can be a back-side grinding process. In this case, the adhesive sheet can be used as a back-side grinding tape. The back-side grinding process can be performed by any suitable method. The back-side grinding process can be the following process: thinning the semiconductor wafer with the adhesive sheet attached until the thickness of the semiconductor wafer becomes, for example, 150 μm or less, 100 μm or less, 50 μm or less, or 30 μm or less. As described above, in the thinning process, the effect of water stripping the adhesive sheet in step (3) can be appropriately utilized. It should be noted that the back-side grinding process can be performed in such a way that the inner side of the annular protrusion becomes a concave portion (i.e., in such a way that a TAIKO (registered trademark) wafer can be obtained). In this case, the thickness of the thinned semiconductor wafer refers to the thickness of the concave portion. In addition, although not particularly limited, the thickness of the semiconductor wafer before back-side grinding can be, for example, about 500 μm to 1000 μm.

[0207] The semiconductor device manufacturing method disclosed in this specification may further include any suitable steps. Examples of such arbitrary steps include, but are not limited to, etching, photolithography, ion implantation, dicing, die bonding, wire bonding, and packaging. The steps listed above may be performed in step (2) above, after step (2) above, before step (3) above, or after step (3) above.

[0208] <Adhesive Sheet Peeling Method>

[0209] According to this specification, a method for peeling an adhesive sheet that has been attached to an adhesive substrate from the substrate is provided. This method may include a water-based peeling step, wherein, at the peeling front of the adhesive sheet from the substrate, while an aqueous peeling liquid is present at the interface between the substrate and the adhesive sheet, the aqueous peeling liquid is introduced into the interface following the movement of the peeling front, and the adhesive sheet is peeled from the substrate. The peeling front, as referred to here, is the position where the adhesive surface of the adhesive sheet begins to separate from the substrate during the peeling process. This water-based peeling step effectively utilizes the aqueous peeling liquid to peel the adhesive sheet from the substrate. The peeling method may preferably be implemented, for example, by peeling any of the adhesive sheets disclosed in this specification from the substrate.

[0210] The substrate in the peeling method disclosed in this specification can be any of the semiconductor wafers exemplified above. These semiconductor wafers can be semiconductor wafers with circuits formed on them. The peeling method disclosed in this specification is preferably used as a method for peeling an adhesive sheet that has been attached to the circuit-forming surface of a semiconductor wafer from the circuit-forming surface. A high-temperature process can be performed after the adhesive sheet is attached to the substrate and before the start of the water peeling process.

[0211] As an adhesive sheet that can be peeled off from the adhered object using the above-described peeling method, any of the adhesive sheets disclosed in this specification may preferably be used. Therefore, the above-described peeling method is suitable as a peeling method for any of the adhesive sheets disclosed in this specification.

[0212] In some embodiments, the above-described peeling method can preferably be implemented by including the following steps: forcibly lifting the adhesive sheet from the adhered object at one end of its outer edge, thereby forming an initial peeling front; supplying an aqueous peeling liquid to the peeling front; and peeling the adhesive sheet from the adhered object while the aqueous peeling liquid enters the interface between the adhesive sheet and the adhered object following the movement of the peeling front. The initial peeling front can be formed, for example, by inserting the tip of a tool such as a cutter or needle into the interface between the adhesive sheet and the adhered object; grasping and lifting the adhesive sheet with a hook or claw; attaching a strong adhesive tape or suction cup to the back of the adhesive sheet and lifting the end of the adhesive sheet; etc. After forming the initial peeling front as described above, supplying the aqueous peeling liquid to the peeling front initiates water peeling, thereby enabling efficient supply of the aqueous peeling liquid to the peeling front. Furthermore, in the above-described peeling method and the adhesive sheet used in the peeling method, it is ideal to simultaneously achieve: good water-repellent properties after the start of peeling is achieved by performing an operation to forcibly form an initial peeling front; and high water resistance reliability without performing the operation.

[0213] In some methods, the above-described peeling method can preferably be performed by supplying an aqueous peeling liquid to the initial peeling front (i.e., supplying the aqueous peeling liquid at the start of aqueous peeling), and then peeling the adhesive sheet without supplying new aqueous peeling liquid. Alternatively, if the aqueous peeling liquid that follows the movement of the peeling front to the interface between the adhesive sheet and the adhered object dries up or becomes insufficient during the aqueous peeling process, the aqueous peeling liquid can be supplied intermittently or continuously after the start of the aqueous peeling. For example, in cases where the length of the peeling front increases as peeling progresses (e.g., in cases where aqueous peeling is performed radially from one end of the outer edge of the disc-shaped adhered object), or where aqueous peeling liquid tends to remain on the surface of the adhered object, it is preferable to supply the aqueous peeling liquid after the start of the aqueous peeling. Furthermore, the location for supplying the aqueous peeling liquid can be one location or multiple locations. When supplying the aqueous peeling liquid after the start of the aqueous peeling, the number of locations where the aqueous peeling liquid is supplied after the start of the aqueous peeling can be increased or decreased.

[0214] It should be noted that the matters disclosed in this specification include the following solutions.

[0215] [1] A semiconductor processing adhesive sheet, which includes an adhesive layer constituting an adhesive surface.

[0216] The initial conventional peel force Fd0 of the adhesive sheet for semiconductor processing is 0.10 N / 20 mm or more, and,

[0217] Standard peel strength Fd after heat treatment at 150℃ for 15 minutes a It is below 1.00N / 20mm.

[0218] [2] A semiconductor processing adhesive sheet, which includes an adhesive layer constituting an adhesive surface.

[0219] The initial conventional peel force Fd0 of the adhesive sheet for semiconductor processing is 0.10 N / 20 mm or more, and,

[0220] Water stripping force Fw a The water stripping force Fw is below 0.30 N / 20 mm. a The test was conducted by supplying water to the peeling front of the adhesive sheet after heat treatment at 150°C for 15 minutes.

[0221] [3] A semiconductor processing adhesive sheet, which includes an adhesive layer constituting an adhesive surface.

[0222] The initial conventional peel force Fd0 of the adhesive sheet for semiconductor processing is 0.10 N / 20 mm or more, and,

[0223] Standard peel strength Fd after heat treatment at 200℃ for 15 minutes b It is below 3.00N / 20mm.

[0224] [4] A semiconductor processing adhesive sheet, which includes an adhesive layer constituting an adhesive surface.

[0225] The initial conventional peel force Fd0 of the adhesive sheet for semiconductor processing is 0.10 N / 20 mm or more, and,

[0226] Water stripping force Fw b The water stripping force Fw is below 2.00 N / 20 mm. b The test was conducted by supplying water to the peeling front of the adhesive sheet after heat treatment at 200°C for 15 minutes.

[0227] [5] The adhesive sheet for semiconductor processing as described in any one of [1] to [4] above, wherein the conventional peel force Fd after heat treatment at 150°C for 15 minutes is... a [N / 20mm] and the standard peel strength Fd after heat treatment at 200℃ for 15 minutes. b [N / 20mm], determined by the following formula: Fd b / Fd a The calculated standard peel force ratio is below 4.0.

[0228] [6] The semiconductor processing adhesive sheet as described in any one of [1] to [5] above, wherein the conventional peel force Fd after heat treatment at 150°C for 15 minutes is... a [N / 20mm] and the standard peel strength Fd after heat treatment at 200℃ for 15 minutes. b [N / 20mm], determined by the following formula: Fd b -Fd a The calculated difference in conventional peel force is below 1.50 N / 20 mm.

[0229] [7] The semiconductor processing adhesive sheet as described in any one of [1] to [6] above includes a substrate supporting the adhesive layer.

[0230] [8] A semiconductor processing adhesive sheet, which includes an adhesive layer constituting an adhesive surface, satisfies condition A below and satisfies at least one of conditions B to E below.

[0231] (Condition A) The initial conventional peel force Fd0 is above 0.10 N / 20 mm.

[0232] (Condition B) Standard peel strength Fd after heat treatment at 150°C for 15 minutes a It is below 1.00N / 20mm.

[0233] (Condition C) After heat treatment at 150°C for 15 minutes, water is supplied to the peeling front of the adhesive sheet as it peels from the adherend, and the water peeling force Fw is measured. a It is below 0.30N / 20mm.

[0234] (Condition D) Standard peel strength Fd after heat treatment at 200℃ for 15 minutes b It is below 3.00N / 20mm.

[0235] (Condition E) After heat treatment at 200°C for 15 minutes, water was supplied to the peeling front of the adhesive sheet as it peels from the adherend, and the water peeling force Fw was measured. b It is below 2.00N / 20mm.

[0236] [9] The adhesive sheet described in [8] above satisfies at least conditions A and C above.

[0237]

[10] The adhesive sheet for semiconductor processing as described in any one of [1] to [9] above, wherein the adhesive layer is an acrylic adhesive layer.

[0238]

[11] The semiconductor processing adhesive sheet as described in any one of [1] to

[10] above, wherein the adhesive layer, as a heat-resistant release agent, comprises at least one compound A selected from the group consisting of surfactants and compounds having a polyoxyalkylene backbone.

[0239]

[12] The semiconductor processing adhesive sheet as described in any one of [1] to

[11] above, wherein a crosslinking agent is used in the adhesive layer.

[0240]

[13] The semiconductor processing adhesive sheet as described in any one of [1] to

[12] above, wherein the crosslinking agent comprises an isocyanate-based crosslinking agent.

[0241]

[14] The semiconductor processing adhesive sheet as described in any one of [1] to

[12] above, wherein the crosslinking agent comprises an isocyanate-based crosslinking agent and an epoxy-based crosslinking agent.

[0242]

[15] A semiconductor device manufacturing method, which is a method for manufacturing a semiconductor device using any one of [1] to

[14] above, comprising the following steps:

[0243] Step (1) involves attaching the bonding surface of the semiconductor processing adhesive sheet to the circuit forming surface side of the semiconductor wafer having a circuit forming surface.

[0244] Step (2) involves processing the semiconductor wafer to which the adhesive sheet has been attached from the side opposite to the adhesive sheet; and

[0245] Step (3) involves peeling the adhesive sheet from the processed semiconductor wafer.

[0246]

[16] The semiconductor device manufacturing method as described in

[15] above includes a high-temperature exposure process: a high-temperature process (e.g., a high-temperature process of 100°C or above, preferably 60°C or above) is performed after the above process (1) and before the above process (3).

[0247]

[17] The semiconductor device manufacturing method as described in

[15] or

[16] above, wherein the above-mentioned step (3) is performed using a water stripping method.

[0248] Example

[0249] The following describes some embodiments of the present invention, but it is not intended to limit the invention to the contents shown in the embodiments. It should be noted that, unless otherwise specified, "parts" and "%" in the following description are based on weight.

[0250] <Evaluation Methods>

[0251] 1. Determination of initial conventional peel force Fd0

[0252] The adhesive sheet to be tested was cut into strips with a width of 20 mm to prepare test pieces. Under an environment of 23°C and 50% RH, the adhesive surface of the test piece was pressed against the mirror surface of a 6-inch silicon wafer (manufactured by Shin-Etsu Chemical Co., Ltd., 6-inch N<100>-100) using a hand roller and left for 30 minutes to prepare an evaluation sample.

[0253] Then, at 23°C and 50% RH, a cutter was inserted into the interface between the test piece and the substrate of the above-mentioned evaluation sample, and one end of the test piece in the longitudinal direction was peeled from the substrate. The peel strength was determined according to JIS Z0237:2009, "10.4.1 Method 1: Peel Adhesion Force at 180° Relative to the Test Plate." Specifically, at a test temperature of 23°C, a tensile testing machine (Shimadzu Autograph EZ-S precision universal testing machine) was used at a tensile speed of 300 mm / min and a peel angle of 180 degrees. The peel strength was measured by peeling the test piece attached to the substrate from bottom to top. Three measurements were performed, and their average value was taken as the initial conventional peel force Fd0 [N / 20 mm].

[0254] 2. Determination of initial water stripping force Fw0

[0255] In the determination of the initial conventional peel force Fd0, 20 μL of distilled water was supplied to the position where the test piece began to separate from the adhered material (the peel front) during the peeling process, and the peel strength after the supply of distilled water was measured. For the measurement, each peel strength was measured sequentially (i.e., 3 times), and their average value was taken as the initial water peel force Fw0 [N / 20 mm].

[0256] 3. Determination of conventional peel force after heating

[0257] (Standard peel force Fd after heating at 150℃) a )

[0258] Evaluation samples prepared in the same manner as the initial conventional peel force Fd0 determination described above were heated at 150°C for 15 minutes. After heating, they were cooled at room temperature (25°C) for 30 minutes. After cooling, the peel strength was measured in the same manner as the initial conventional peel force Fd0 determination described above. Three measurements were performed, and their average value was taken as the conventional peel force Fd0 after heating at 150°C. a [N / 20mm].

[0259] (Standard peel force Fd after heating at 200℃) b )

[0260] Except for changing the heating conditions to 200°C and 15 minutes, the standard peel force Fd after heating at 150°C as described above was maintained. a The same method was used to measure the conventional peel force Fd after heating at 200℃. b [N / 20mm].

[0261] 4. Determination of water stripping force after heating

[0262] (Water peeling force Fw after heating at 150℃) a )

[0263] The standard peel force Fd after heating to 150℃ is as described above. a In the test, 20 μL of distilled water was supplied to the point where the test piece began to separate from the adhered material (the peeling front) midway through the process, and the peel strength after the supply of distilled water was measured. For the test, each peel strength was measured sequentially (i.e., three times), and the average value was taken as the water peel force Fw after heating at 150°C. a [N / 20mm].

[0264] (Water peeling force Fw after heating at 200℃) b )

[0265] In addition to changing the heating conditions to 200°C and 15 minutes, the water peeling force Fw after heating at 150°C was also adjusted accordingly. a The same method was used to measure the water peel force Fw after heating at 200℃. b [N / 20mm].

[0266] <Example 1>

[0267] (Preparation of the adhesive composition)

[0268] A monomer composition was prepared by mixing 100 parts of n-butyl acrylate (BA) and 3 parts of acrylic acid as monomer raw materials, 0.2 parts of 2,2'-azobisisobutyronitrile (AIBN) as polymerization initiator, and toluene as polymerization solvent.

[0269] The above monomer composition was placed into a polymerization apparatus consisting of a 1L round-bottom detachable flask equipped with a detachable cap, separatory funnel, thermometer, nitrogen inlet tube, Liebig condenser, vacuum seal, stir bar, and stirring blades. The mixture was stirred while being purged with nitrogen at room temperature for 2 hours. Then, polymerization was carried out under a nitrogen flow, with stirring, at 60°C for 5 hours, yielding a solution of polymer P1 (Mw approximately 1 million). The Tg calculated using the Fox equation based on the composition of the above monomer raw materials was -52.3°C.

[0270] The solution of polymer P1 was cooled to room temperature. 2.0 parts of an isocyanate-based crosslinking agent (trimethylolpropane / toluene diisocyanate trimer adduct, manufactured by Tosoh Corporation, trade name "Coronate L", solid content concentration 75% by weight) and 0.7 parts of an epoxy-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "TETRAD C") were added relative to 100 parts of polymer P1 in the solution. The mixture was then prepared to obtain adhesive composition C1.

[0271] (Production and evaluation of adhesive sheets)

[0272] Adhesive composition C1 was applied to the release surface of a 38 μm thick release film (Mitsubishi Resin Co., Ltd., MRF38) with a polysiloxane-treated release surface on one side of a polyethylene terephthalate (PET) film. The film was dried at 140°C for 2 minutes to form an adhesive layer with a thickness of 20 μm. This adhesive layer was then bonded to the easy-to-bond surface of an easy-to-bond treated PET film (50 μm thick) serving as a substrate. The film was then aged at 50°C for 2 days to obtain the adhesive sheet (single-sided adhesive sheet with a substrate) described in this example.

[0273] For the obtained adhesive sheet, the peel force was measured using the above method, and the conventional peel force ratio (Fd) was calculated from the measured value. b / Fd a ) and poor conventional peel strength (Fd) b -Fd a The results are shown in Table 1.

[0274] <Example 2>

[0275] To the solution of polymer P1, relative to 100 parts of polymer P1 in the solution, 0.1 parts of compound A, i.e., nonionic surfactant A1 (polyoxyethylene sorbitan monolaurate, sorbitan fatty acid ester manufactured by Kao Corporation, trade name "Rheodol TW-L120", with 20 moles of ethylene oxide addition and HLB of 16.7), which does not undergo phase separation in test I above, are added. Except as described above, adhesive composition C2 is prepared in the same manner as adhesive composition C1.

[0276] It should be noted that the aforementioned nonionic surfactant A1 is used in the form of an ethyl acetate solution and in the amount described above, based on the solid component. The same applies to the preparation of adhesive compositions C3 to C5.

[0277] In addition to using the adhesive composition C2 described above, the adhesive sheet involved in this example was obtained in the same manner as in Example 1.

[0278] The obtained adhesive sheet was evaluated in the same way as in Example 1. The results are shown in Table 1.

[0279] <Examples 3~5>

[0280] As shown in Table 1, the amount of nonionic surfactant A1 added relative to 100 parts of polymer P1 was varied, and the adhesive compositions C3 to C5 of Examples 3 to 5 were prepared in the same manner as the preparation of adhesive composition C2. Except for using the adhesive compositions C3 to C5 described above, the adhesive sheets of Examples 3 to 5 were obtained in the same manner as in Example 1. The obtained adhesive sheets were evaluated in the same way as in Example 1. The results are shown in Table 1.

[0281] [Table 1]

[0282] Table 1

[0283]

[0284] As shown in Table 1, the adhesive sheets of Examples 2-5 exhibit significantly lower peel strength after high-temperature exposure compared to the adhesive sheet of Example 1, demonstrating excellent balance between adhesion and bonding reliability relative to the adhered objects during processing. Examples 3-5 show particularly outstanding results.

[0285] The specific examples of the present invention have been described in detail above, but they are merely examples and do not limit the scope of the claims. The technology described in the claims includes technologies that have undergone various modifications and alterations to the specific examples illustrated above.

Claims

1. A semiconductor processing adhesive sheet which is a semiconductor processing adhesive sheet comprising an adhesive layer constituting an adhesive surface, the adhesive layer comprises a base polymer, a surfactant, and a crosslinking agent in a state after crosslinking reaction or in a state before crosslinking reaction, the surfactant is a compound having two or more hydroxyl groups in one molecule, the surfactant is used in an amount of 0.5 parts by weight or more and less than 1.0 parts by weight with respect to 100 parts by weight of the base polymer, the crosslinking agent is used in an amount of 1.5 parts by weight or more and 12 parts by weight or less with respect to 100 parts by weight of the base polymer, the initial general peeling force Fd0 of the semiconductor processing adhesive sheet is 0.10 N / 20 mm or more, and The regular peeling force Fd after the heat treatment at 150°C for 15 minutes is 0.5 N / 20 mm or less, compared with the initial regular peeling force FdO a The regular peeling force Fd a is 1.00 N / 20 mm or less.

2. The adhesive sheet for semiconductor processing according to claim 1, wherein the initial general peeling force Fd0 of the semiconductor processing adhesive sheet is 0.10 N / 20 mm or more and less than 1.00 N / 20 mm, and Water peel force Fw a is 0.30 N / 20 mm or less, the water peel force Fw a is measured by supplying water to the peel front of the adhesive sheet peeled from the adherend after heat treatment at 150°C for 15 minutes.

3. The adhesive sheet for semiconductor processing according to claim 1, wherein The regular peeling force Fd after the heat treatment at 200°C for 15 minutes is 3.00 N / 20 mm or less compared to the initial regular peeling force Fd0 b The regular peeling force Fd b is 3.00 N / 20 mm or less.

4. The adhesive sheet for semiconductor processing according to claim 1, wherein the initial general peeling force Fd0 of the semiconductor processing adhesive sheet is 0.10 N / 20 mm or more and less than 1.00 N / 20 mm, and water peeling force Fw b is 2.00 N / 20 mm or less, the water peeling force Fw b is measured by supplying water to the peeling front of the adhesive sheet peeled from the adherend after heat treatment at 200°C for 15 minutes, The regular peeling force Fd after the heat treatment at 200°C for 15 minutes compared with the initial regular peeling force FdO b goes up.

5. The adhesive sheet for semiconductor processing according to any one of claims 1 to 4, wherein Conventional peel strength Fd after heat treatment at 150°C for 15 minutes a [N / 20 mm] and conventional peel strength Fd after heat treatment at 200°C for 15 minutes b [N / 20 mm], by the following formula: Fd b / Fd a The calculated conventional peel strength ratio was 4.0 or less.

6. The adhesive sheet for semiconductor processing according to any one of claims 1 to 4, wherein The regular peel force Fd after heat treatment at 150°C for 15 minutes a [N / 20mm] and the regular peel force Fd after heat treatment at 200°C for 15 minutes b [N / 20mm], by the following formula: Fd b -Fd a The difference in the calculated regular peel force is 1.50 N / 20mm or less.

7. The semiconductor processing adhesive sheet according to any one of claims 1 to 4, comprising a substrate supporting the adhesive layer.

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