JP2021097074A - Pressure-sensitive adhesive sheet for semiconductor processing - Google Patents

Abstract

To provide a pressure-sensitive adhesive sheet for semiconductor processing that is also suitable for usage modes including high temperature processes.SOLUTION: There is provided a pressure-sensitive adhesive sheet for semiconductor processing that includes an adhesive layer constituting an adhesive surface. In one aspect, the pressure-sensitive adhesive sheet for semiconductor processing has an initial normal peel-off force Fd0 of 0.10 N/20 mm or more, and a normal peel-off force Fda of 1.00 N/20 mm or less after heat treatment at 150°C for 15 minutes.SELECTED DRAWING: Figure 1

Description

The present invention relates to an adhesive sheet for semiconductor processing.

In the process of manufacturing a semiconductor element, a process of grinding, cutting, or the like on a circuit-formed semiconductor wafer is generally performed on the circuit-forming surface side of the semiconductor wafer (adhesive body) in order to protect or fix the semiconductor wafer. This is performed with an adhesive sheet (adhesive sheet for semiconductor processing) attached to the wafer. For example, when grinding (back grinding) the back surface of a semiconductor wafer, a back grind tape is used to protect the circuit forming surface (front surface) of the semiconductor wafer and to hold (fix) the semiconductor wafer. (For example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-212441

The back grind tape and other adhesive sheets for semiconductor processing are peeled off from the adherend at a desired timing after fulfilling the purpose of use. Therefore, the pressure-sensitive adhesive sheet for semiconductor processing is required to have both adhesion to an adherend at the time of processing and bonding reliability and peelability at the time of peeling from the adherend in a well-balanced manner. However, even in the room temperature range, even if the pressure-sensitive adhesive sheet for semiconductor processing has both of the above characteristics in a well-balanced manner, the peeling force greatly increases when it is exposed to a high temperature state of a predetermined temperature or higher after being attached to the adherend. There was a concern that adhesive residue on the adherend and damage to the adherend due to the load at the time of peeling might occur. In particular, in recent years, semiconductor wafers after backgrinding have tended to become thinner as semiconductor elements become smaller, thinner, and more integrated, and are adhered even after undergoing a processing process (high temperature process) that is exposed to high temperatures. An adhesive sheet for semiconductor processing that can be peeled off while suppressing the load on the body is desired.

The present invention has been created in view of the above circumstances, and an object of the present invention is to provide an adhesive sheet for semiconductor processing suitable for a usage mode including a high temperature process.

The pressure-sensitive adhesive sheet for semiconductor processing disclosed herein includes a pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive surface. In some aspects of the above-mentioned adhesive sheet for semiconductor processing (hereinafter, may be simply referred to as "adhesive sheet"), the adhesive sheet has an initial normal peeling force Fd ₀ of 0.10 N / 20 mm or more (hereinafter, may be simply referred to as "adhesive sheet"). hereinafter referred to as "condition a".), and also referred to as 0.99 ° C. for 15 minutes normal release force Fd _a after the heat treatment is not more than 1.00 N / 20 mm (hereinafter "condition B".). As described above, the adhesive sheet in which the lower limit of the initial normal peeling force Fd _{0 and the upper limit of the normal peeling force Fda a} after heat treatment at 150 ° C. for 15 minutes (hereinafter, also referred to as “normal peeling force after heating at 150 ° C.”) is limited. Even in the usage mode including the high temperature process, the adhesion to the adherend and the joining reliability at the time of processing and the peelability at the time of peeling from the adherend can be balanced in a well-balanced manner.

In some aspects of the pressure-sensitive adhesive sheet for semiconductor processing disclosed herein, the pressure-sensitive adhesive sheet satisfies the above-mentioned condition A and is heat-treated at 150 ° C. for 15 minutes, and then from the adherend of the pressure-sensitive adhesive sheet. water release force Fw _a measured by supplying water to the peeling front is less than 0.30 N / 20 mm (hereinafter referred to as "condition C".). Thus _(hereinafter also referred to as "0.99 ° C. After heating the water peel force".) Initial normal release force water peel force 15 minutes after heat treatment at lower and 0.99 ° C. of Fd ₀ Fw a pressure-sensitive adhesive sheet which limit is restricted in Even in the usage mode including the high temperature process, the adhesion to the adherend and the joining reliability at the time of processing and the peelability at the time of peeling from the adherend can be balanced in a well-balanced manner. By performing the peeling from the adherend by the water peeling method, the load on the adherend can be further reduced.

In some embodiments of the semiconductor processing adhesive sheet disclosed herein, the PSA sheet satisfies the above conditions A, and after the heat treatment for 15 minutes at 200 ° C. Normal peel force Fd _b is 3. It is 00 N / 20 mm or less (hereinafter, also referred to as “condition D”). Thus _(hereinafter also referred to as "200 ° C. After heating Normal peel strength".) Initial normal release force Fd ₀ lower and 200 ° C. Normal peel strength after heat treatment for 15 minutes at Fd b is pressure-sensitive adhesive sheet limit is restricted in Even in a usage mode including a high temperature process under stricter conditions, it is possible to achieve a good balance between adhesion to an adherend during processing and joint reliability and detachability when peeling from the adherend.

In some aspects of the pressure-sensitive adhesive sheet for semiconductor processing disclosed herein, the pressure-sensitive adhesive sheet satisfies the above-mentioned condition A and is heat-treated at 200 ° C. for 15 minutes, and then from the adherend of the pressure-sensitive adhesive sheet. _{The water peeling force Fw b} measured by supplying water to the peeling front is 2.00 N / 20 mm or less (hereinafter, also referred to as “condition E”). As described above, the adhesive sheet in which the lower limit of the initial normal peeling force Fd _{0 and the upper limit of the water peeling force Fw b} after heat treatment at 200 ° C. for 15 minutes (hereinafter, also referred to as “water peeling force after heating at 200 ° C.”) is limited. Even in a usage mode including a high temperature process under stricter conditions, the adhesion to the adherend during processing and the joining reliability can be balanced with the peelability when peeling from the adherend. By performing the peeling from the adherend by the water peeling method, the load on the adherend can be further reduced.

In some embodiments of the semiconductor processing adhesive sheet disclosed herein, the PSA sheet is an ordinary release force Fd a _[N / 20mm] after the heat treatment for 15 minutes at 0.99 ° C., at 200 ° C. since the normal peel strength after the heat treatment for 15 minutes _Fd b [N / 20mm], the following _equation: Fd b / Fd _a; normal release force ratios calculated by is 4.0 or less. As a result, the adhesive sheet is not easily affected by the peeling force even if processing unevenness such as temperature unevenness occurs in the high temperature process.

In some embodiments of the semiconductor processing adhesive sheet disclosed herein, the PSA sheet is an ordinary release force Fd a _[N / 20mm] after the heat treatment for 15 minutes at 0.99 ° C., at 200 ° C. since the normal peel strength after the heat treatment for 15 minutes _Fd b [N / 20mm], the following _equation: Fd b -Fd _a; normal peel force difference calculated by is less than 1.50N / 20mm. As a result, the adhesive sheet is not easily affected by the peeling force even if processing unevenness such as temperature unevenness occurs in the high temperature process.

It should be noted that an appropriate combination of the above-mentioned elements may be included in the scope of the invention for which protection by the patent is sought by the present patent application.

It is sectional drawing which shows typically one structural example of the pressure-sensitive adhesive sheet. It is sectional drawing which shows typically another structural example of the adhesive sheet. It is sectional drawing which shows typically another structural example of the adhesive sheet. It is sectional drawing which shows typically another structural example of the adhesive sheet. It is sectional drawing which shows typically another structural example of the adhesive sheet. It is sectional drawing which shows typically another structural example of the adhesive sheet.

Hereinafter, preferred embodiments of the present invention will be described. Matters other than those specifically mentioned in the present specification and necessary for the implementation of the present invention are based on the teachings regarding the implementation of the invention described in the present specification and the common general knowledge at the time of filing. Can be understood by those skilled in the art. The present invention can be carried out based on the contents disclosed in the present specification and common general technical knowledge in the art. Further, in the following drawings, members / parts having the same function may be described with the same reference numerals, and duplicate description may be omitted or simplified. Further, the embodiments described in the drawings are modeled for clearly explaining the present invention, and do not necessarily accurately represent the size and scale of the actually provided product.

In this specification, the adhesive sheet is peeled from the adherend by using an aqueous stripping solution such as water (typically, the aqueous stripping solution is supplied to the peeling front from the adherend to peel off). May be referred to as "water peeling" or "water peeling method".

As used herein, the term "acrylic polymer" refers to a polymer derived from a monomer 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 acrylic monomer means a monomer having at least one (meth) acryloyl group in one molecule. Further, in this specification, "(meth) acryloyl" means a comprehensively referring to acryloyl and methacryloyl. Similarly, "(meth) acrylate" means acrylate and methacrylate, and "(meth) acrylic" means acrylic and methacryl, respectively.

Further, in this specification, the "active energy ray" includes light such as ultraviolet rays, visible rays and infrared rays, and radiation such as α rays, β rays, γ rays, electron rays, neutron rays and X-rays. It is a concept to do.

<Structure example of adhesive sheet>
The pressure-sensitive adhesive sheet disclosed herein comprises a pressure-sensitive adhesive layer. This pressure-sensitive adhesive layer typically constitutes at least one surface of the pressure-sensitive adhesive sheet. The pressure-sensitive adhesive sheet may be a pressure-sensitive adhesive sheet with a base material having an adhesive layer on one side or both sides of the base material (support), and may be a pressure-sensitive adhesive sheet without a base material (base material-less pressure-sensitive adhesive sheet). There may be.
The concept of the pressure-sensitive adhesive sheet as used herein may include what is called an pressure-sensitive adhesive tape, a pressure-sensitive adhesive label, a pressure-sensitive adhesive film, or the like. Further, the pressure-sensitive adhesive layer is typically formed continuously, but is not limited to such a form, and the pressure-sensitive adhesive layer is formed in a regular or random pattern such as a dot shape or a stripe shape. It may be. In addition, the pressure-sensitive adhesive sheet provided by the present specification may be in the form of a roll or in the form of a single leaf. Alternatively, the pressure-sensitive adhesive sheet may be further processed into various shapes.

The pressure-sensitive adhesive sheet disclosed herein may have, for example, the cross-sectional structure schematically shown in FIGS. 1 to 6. Of these, FIGS. 1 and 2 are configuration examples of a single-sided adhesive base-attached pressure-sensitive adhesive sheet (base-based single-sided pressure-sensitive adhesive sheet). In the pressure-sensitive adhesive sheet 1 shown in FIG. 1, a pressure-sensitive adhesive layer 21 is provided on one surface 10A (non-peelable) of the base material 10, and the surface (adhesive surface) 21A of the pressure-sensitive adhesive layer 21 is peeled off at least on the pressure-sensitive adhesive layer side. It has a structure protected by a release liner 31 which is a surface. The pressure-sensitive adhesive sheet 2 shown in FIG. 2 has a structure in which the pressure-sensitive adhesive layer 21 is provided on one surface 10A (non-peelable) of the base material 10. In this pressure-sensitive adhesive sheet 2, the other surface 10B of the base material 10 is a peeling surface, and when the pressure-sensitive adhesive sheet 2 is wound, the pressure-sensitive adhesive layer 21 comes into contact with the other side surface 10B, and the surface of the pressure-sensitive adhesive layer (adhesive). Surface) 21A is protected by the other surface 10B of the base material 10.

3 and 4 are configuration examples of a double-sided adhesive type pressure-sensitive adhesive sheet with a base material (double-sided pressure-sensitive adhesive sheet with a base material). The pressure-sensitive adhesive sheet 3 shown in FIG. 3 has a pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer) 21 and a pressure-sensitive adhesive layer (second pressure-sensitive adhesive) on the first surface 10A and the second surface 10B (both non-peelable) of the base material 10. The agent layer) 22 is provided, and the surface of the first adhesive layer 21 (first adhesive surface) and the surface of the second adhesive layer 22 (second adhesive surface) are at least the peeling surface on the adhesive layer side. It has a structure protected by the release liners 31 and 32, respectively. In the pressure-sensitive adhesive sheet 4 shown in FIG. 4, a first pressure-sensitive adhesive layer 21 and a second pressure-sensitive adhesive layer 22 are provided on the first surface 10A and the second surface 10B (both are non-peelable) of the base material 10, respectively. Of these, the surface (first adhesive surface) of the first pressure-sensitive adhesive layer 21 has a structure protected by a release liner 31 having both sides as release surfaces. The adhesive sheet 4 is wound around the adhesive sheet 4 so that the front surface (second adhesive surface) of the second adhesive layer 22 is brought into contact with the back surface of the release liner 31, so that the second adhesive surface is also formed by the release liner 31. It can be a protected configuration.

5 and 6 are configuration examples of a base material-less double-sided adhesive adhesive sheet (base material-less double-sided adhesive sheet). In the pressure-sensitive adhesive sheet 5 shown in FIG. 5, one surface (first adhesive surface) 21A and the other surface (second adhesive surface) 21B of the base material-less pressure-sensitive adhesive layer 21 have at least the pressure-sensitive adhesive layer side as a peeling surface. It has a structure protected by the release liners 31 and 32, respectively. The pressure-sensitive adhesive sheet 6 shown in FIG. 6 has a structure in which one surface (first pressure-sensitive adhesive surface) 21A of the pressure-sensitive adhesive layer 21 is protected by a release liner 31 having both sides as release surfaces, and the adhesive sheet 6 is wound around the adhesive sheet 6. Then, the other surface (second adhesive surface) 21B of the pressure-sensitive adhesive layer 21 comes into contact with the back surface of the release liner 31, so that the other surface 21B can also be protected by the release liner 31.
A double-sided pressure-sensitive adhesive sheet without a base material or with a base material can be used as a single-sided pressure-sensitive adhesive sheet with a base material by laminating a non-peelable base material on one of the pressure-sensitive adhesive surfaces.

The pressure-sensitive adhesive sheet before use (before sticking to the adherend) may be in the form of a pressure-sensitive adhesive sheet with a release liner whose adhesive surface is protected by a release liner, for example, as shown in FIGS. 1 to 6. The release liner is not particularly limited, and is, for example, a release liner in which the surface of a liner base material such as a resin film or paper is peeled off, a fluoropolymer (polytetrafluoroethylene, etc.), a polyolefin resin (polyethylene, polypropylene, etc.). ), A release liner made of a low-adhesive material or the like can be used. For the peeling treatment, for example, a silicone-based peeling agent, a long-chain alkyl-based peeling agent, or the like can be used. In some embodiments, the stripped resin film can be preferably used as the strip liner.

When the pressure-sensitive adhesive sheet disclosed herein is in the form of a double-sided pressure-sensitive adhesive sheet with a base material or a double-sided pressure-sensitive adhesive sheet without a base material, the pressure-sensitive adhesive (first pressure-sensitive adhesive) constituting the first pressure-sensitive adhesive surface and the second pressure-sensitive adhesive surface are formed. The pressure-sensitive adhesive (second pressure-sensitive adhesive) may have the same composition or different compositions. A base-less double-sided pressure-sensitive adhesive sheet having different compositions on the first adhesive surface and the second adhesive surface is, for example, a multi-layered pressure-sensitive adhesive in which two or more pressure-sensitive adhesive layers having different compositions are directly laminated (without interposing a base material). It can be realized by layers.

<Adhesive layer>
The pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet disclosed herein is an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive (natural rubber-based, synthetic rubber-based, a mixture thereof, etc.), a silicone-based pressure-sensitive adhesive, and a polyester-based adhesive. A pressure-sensitive adhesive composed of one or more types of pressure-sensitive adhesives selected from various known pressure-sensitive adhesives such as pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, polyether-based pressure-sensitive adhesives, polyamide-based pressure-sensitive adhesives, and fluorine-based pressure-sensitive adhesives. It can be an agent layer. Here, the acrylic pressure-sensitive adhesive refers to a pressure-sensitive adhesive using an acrylic polymer as a base polymer. The same meaning applies to rubber-based pressure-sensitive adhesives and other pressure-sensitive adhesives.
In this specification, the "base polymer" of the pressure-sensitive adhesive means the main component of the polymer contained in the pressure-sensitive adhesive. Further, in this specification, the “main component” refers to a component contained in an amount of more than 50% by weight unless otherwise specified.

(Acrylic adhesive layer)
In some aspects of the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive layer may be an acrylic pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive as a main component. In the pressure-sensitive adhesive sheet provided with the acrylic pressure-sensitive adhesive layer, the pressure-sensitive adhesive properties suitable for semiconductor processing and the light peelability by water peeling can be preferably compatible with each other.

As the acrylic pressure-sensitive adhesive, for example, one containing an acrylic polymer, which is a polymer of a monomer raw material containing an alkyl (meth) acrylate, as a base polymer is preferable. As a constituent component of the monomer raw material, an alkyl (meth) acrylate having a linear or branched alkyl group having 1 to 20 carbon atoms at the ester terminal can be preferably used. Hereinafter, an alkyl (meth) acrylate having an alkyl group having an number of carbon atoms of X or more and Y or less at the ester terminal _{may be referred to as “CXY} alkyl (meth) acrylate”. _{As the C 1-20} alkyl (meth) acrylate, C _1-14 (for example, C _1-12 ) alkyl (meth) acrylate is preferable because it is easy to obtain adhesive properties suitable for semiconductor processing applications. Further, as the C _1-20 alkyl acrylate, a C _1-20 (for example, C _1-14 , typically C _1-12 ) alkyl acrylate is preferable.

Non-limiting specific examples of C _1-20 alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl (meth) acrylate. , Isobutyl (meth) acrylate, s-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) ) Acrylate, Isooctyl (meth) acrylate, Nonyl (meth) acrylate, Isononyl (meth) acrylate, Decyl (meth) acrylate, Isodecyl (meth) acrylate, Undecyl (meth) acrylate, Dodecyl (meth) acrylate, Tridecyl (meth) acrylate , Tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecil (meth) acrylate, ecocil (meth) acrylate and the like. These alkyl (meth) acrylates may 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 comprises at least one of EA, BA, 2EHA and LA, more preferably contains at least one of EA, BA and 2EHA, and at least one of BA and 2EHA. It is more preferable to include.

_{In some embodiments, the proportion of C 1-20} alkyl (meth) acrylate in the monomer raw material is usually 40% by weight or more, and 50% by weight, because it is easy to balance the characteristics. It is preferably more than%, for example, 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 ratio of C 1-20} alkyl (meth) acrylate in the above-mentioned monomer raw material is usually preferably 99.9% by weight or less, may be 99% by weight or less, or 98% by weight or less. Good. From the viewpoint of facilitating the formation of a pressure-sensitive adhesive sheet suitable for light peeling by supplying an aqueous stripping solution to the stripping front from the adherend, in some embodiments, C _1-20 alkyl (meth) in the above-mentioned monomer raw material. The proportion of the acrylate may be, for example, 95% by weight or less, 85% by weight or less, less than 80% by weight, 70% by weight or less, or 65% by weight or less.

The monomer raw material used in the synthesis of the acrylic polymer may further contain a submonomer having copolymerizability with the alkyl (meth) acrylate as described above. The submonomer can be useful for introducing cross-linking points into the acrylic polymer and increasing the cohesive force of the acrylic polymer.

As the submonomer, for example, the following functional group-containing monomers can be used alone or in combination of two or more.
Hydroxy group-containing monomers: For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (4-hydroxymethylcyclohexyl). Hydroxyalkyl (meth) acrylates such as methyl (meth) acrylate; unsaturated alcohols such as vinyl alcohol and allyl alcohol; ether compounds such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether and diethylene glycol monovinyl ether.
Carboxy group-containing monomer: Ethylene unsaturated monocarboxylic acid such as acrylic acid (AA), methacrylic acid (MAA), crotonic acid, isocrotonic acid; ethylenically non-ethylic acid such as maleic acid, fumaric acid, itaconic acid, citraconic acid Saturated dicarboxylic acid.
Acid anhydride group-containing monomer: For example, maleic anhydride, itaconic anhydride.
Monomers having a nitrogen atom-containing ring: for example, N-vinyl-2-pyrrolidone, methyl-N-vinylpyrrolidone, vinylpyridine, vinylpyrazine, vinylpyrimidine, N-vinylpiperidone, N-vinylpiperazine, N-vinylpyrol, N-vinyl. Imidazole, N-vinyloxazole, N-vinylmorpholin, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazine-2-one, N-vinyl-3,5- Morpholindione, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole, N-vinylisothiazole, N- (meth) acryloyl morpholine, N- (meth) acryloyl-2-pyrrolidone, N- (meth) acryloyl Piperidine, N- (meth) acryloylpyrrolidin, etc.
Amide group-containing monomers: For example, (meth) acrylamide; N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl (meth) acrylamide, N, N-diisopropyl (meth). N, N-dialkyl (meth) acrylamide such as acrylamide, N, N-di (n-butyl) (meth) acrylamide, N, N-di (t-butyl) (meth) acrylamide; N-ethyl (meth) acrylamide , N-alkyl (meth) acrylamide such as N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, Nn-butyl (meth) acrylamide; N-vinylcarboxylic acid amides such as N-vinylacetamide; Monomers having a hydroxyl group and an amide group, for example, N- (2-hydroxyethyl) (meth) acrylamide, N- (2-hydroxypropyl) (meth) acrylamide, N- (1-hydroxypropyl) (meth) acrylamide, N- (3-Hydroxypropyl) (meth) acrylamide, N- (2-hydroxybutyl) (meth) acrylamide, N- (3-hydroxybutyl) (meth) acrylamide, N- (4-hydroxybutyl) (meth) N-Hydroxyalkyl (meth) acrylamide such as acrylamide; monomers having an alkoxy group and an amide group, for example, N-methoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide. N-alkoxyalkyl (meth) acrylamide such as N, N-dialkylaminoalkyl (meth) acrylamide such as N, N-dimethylaminopropyl (meth) acrylamide and the like.
Amino group-containing monomer: for example, aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate.
Monomers having a succinimide skeleton: for example, N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, N- (meth) acryloyl-8-oxyhexamethylene succinimide and the like.
Maleimides: For example, N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide and the like.
Itaconimides: For example, N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-lauryl. Itaconimide, etc.
Epoxy group-containing monomers: for example, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, allyl glycidyl ether.
Cyano group-containing monomers: for example, acrylonitrile, methacrylonitrile.
Keto group-containing monomer: For example, diacetone (meth) acrylamide, diacetone (meth) acrylate, vinyl methyl ketone, vinyl ethyl ketone, allyl acetoacetate, vinyl acetoacetate.
Alkoxysilyl group-containing monomers: for example, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxipropylmethyldimethoxysilane, 3- (meth) acryloxy. Alkoxysilyl group-containing (meth) acrylates such as propylmethyldiethoxysilane, alkoxysilyl group-containing vinyl compounds such as vinyltrimethoxysilane and vinyltriethoxysilane, and the like.
Amino group-containing monomer: for example, aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate.
Monomers having an epoxy group: for example, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, allyl glycidyl ether.
Monomers containing sulfonic acid groups or phosphoric acid groups: for example, styrene sulfonic acid, allyl sulfonic acid, sodium vinyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfo. Propyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid, 2-hydroxyethylacryloyl phosphate, etc.
Isocyanate group-containing monomers: for example, 2-isocyanatoethyl (meth) acrylate, (meth) acryloyl isocyanate, m-isopropenyl-α, α-dimethylbenzyl isocyanate.

The amount of the functional group-containing monomer may be appropriately selected so as to achieve a desired cohesive force, and is not particularly limited. Usually, from the viewpoint of achieving a good balance between cohesive force and other properties (for example, adhesiveness), the amount of functional group-containing monomers (when two or more kinds of functional group-containing monomers are used, the total amount thereof) is a monomer. It is suitable to be 0.1% by weight or more of the whole raw material, preferably 0.3% by weight or more, for example, 1% by weight or more. The amount of the functional group-containing monomer may be, for example, 50% by weight or less of the total monomer raw material, or 40% by weight or less. From the viewpoint of facilitating the suppression of the increase in peeling force due to heating, in some embodiments, the amount of the functional group-containing monomer may be 30% by weight or less, 25% by weight or less, or 20% by weight or less of the total monomer raw material. It may be 10% by weight or less, or 5% by weight or less.

In some embodiments, the monomer raw material may include a hydroxyl group-containing monomer as the functional group-containing monomer. When a hydroxyl group-containing monomer is used, the amount used is not particularly limited, and may be, for example, 0.01% by weight or more, 0.1% by weight or more, or 0.5% by weight or more of the entire monomer raw material. It may be 1% by weight or more, 5% by weight or more, or 10% by weight or more. In some embodiments, the amount of the hydroxyl group-containing monomer used can be, for example, 50% by weight or less of the total monomer raw material, and is usually preferably 40% by weight or less from the viewpoint of suppressing water absorption of the pressure-sensitive adhesive. It may be 30% by weight or less, 25% by weight or less, or 20% by weight or less. Further, in some embodiments, the amount of the hydroxyl group-containing monomer used may be 15% by weight or less of the total monomer raw material, 10% by weight or less, or 5% by weight or less. Alternatively, it is not necessary to use a hydroxyl group-containing monomer.

In some embodiments, the monomer raw material may include a carboxy group-containing monomer as the functional group-containing monomer. The ratio of the carboxy group-containing monomer to the total monomer raw material used for the synthesis of the acrylic polymer may be, for example, 15% by weight or less, 10% by weight or less, and suppresses water absorption of the pressure-sensitive adhesive layer during semiconductor processing. From the viewpoint, it is preferably 7% by weight or less, 5% by weight or less, or 3% by weight or less. The monomer raw material does not have to contain substantially no carboxy group-containing monomer. Here, the fact that the carboxy group-containing monomer is substantially not contained means that the carboxy group-containing monomer is not used at least intentionally.

In some embodiments, the monomer raw material may include, as the functional group-containing monomer, a monomer having a nitrogen atom. The use of a monomer having a nitrogen atom can impart appropriate polarity to the pressure-sensitive adhesive. This can be advantageous in realizing an adhesive sheet suitable for light peeling by supplying an aqueous stripping liquid such as water. A preferred example of a monomer having a nitrogen atom is a monomer having a nitrogen atom-containing ring. Examples of the monomer having a nitrogen atom-containing ring include N-vinyl-type compounds such as N-vinyl-2-pyrrolidone (N-vinyl cyclic amide and the like) and N- (meth) acryloylmorpholine and the like from the viewpoint of compatibility and the like. -(Meta) acryloyl type compounds can be preferably adopted.

When a monomer having a nitrogen atom (for example, a monomer having a nitrogen atom-containing ring) is used, the amount used is not particularly limited, and may be, for example, 1% by weight or more of the entire monomer raw material, or 2% by weight or more. It may be 3% by weight or more, 5% by weight or more, or 7% by weight or more. From the viewpoint of obtaining a higher effect, in some embodiments, the amount of the monomer having a nitrogen atom used may be 10% by weight or more, 15% by weight or more, or 20% by weight or more of the total monomer raw material. Good. Further, from the viewpoint of facilitating the balance of characteristics, it is usually appropriate that the amount of the monomer having a nitrogen atom used is, for example, 40% by weight or less of the entire monomer raw material, and may be 35% by weight or less. It may be 50% by weight or less, or 25% by weight or less. In some embodiments, the amount of the monomer having a nitrogen atom used may be, for example, 20% by weight or less, 15% by weight or less, 10% by weight or less, or 5% by weight or less of the total monomer raw material. May be good. Alternatively, it is not necessary to use a monomer having a nitrogen atom.

The monomer raw material used for preparing the acrylic polymer contains an accessory monomer (hereinafter, also referred to as a copolymerizable monomer) other than the above-mentioned functional group-containing monomer for the purpose of enhancing the cohesiveness of the acrylic polymer. You may.
Non-limiting specific examples of the above-mentioned copolymerizable monomer include the following.
Alkoxy group-containing monomer: Alkoxyalkyl (meth) acrylate such as 2-methoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate (alkoxyalkyl (meth) acrylate) Classes: Alkoxy (poly) alkylene glycol (meth) acrylates such as methoxyethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, and methoxypolypropylene glycol (meth) acrylate.
Vinyl esters: For example, vinyl acetate, vinyl propionate and the like.
Vinyl ethers: For example, vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.
Aromatic vinyl compounds: for example, styrene, α-methylstyrene, vinyltoluene and the like.
Olefins: For example, ethylene, butadiene, isoprene, isobutylene and the like.
(Meta) acrylic acid ester having an alicyclic hydrocarbon group: For example, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate and the like. Alicyclic hydrocarbon group-containing (meth) acrylate.
Aromatic ring-containing (meth) acrylate: For example, aryl (meth) acrylate such as phenyl (meth) acrylate, aryloxyalkyl (meth) acrylate such as phenoxyethyl (meth) acrylate, and arylalkyl (meth) acrylate such as benzyl (meth) acrylate. ) Acrylate.
In addition, heterocyclic (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate, halogen atom-containing monomers such as vinyl chloride and fluorine atom-containing (meth) acrylates, and organosiloxane chain-containing monomers such as silicone (meth) acrylates. Terpen compound derivative (meth) acrylic acid ester obtained from alcohol, etc.
Such copolymerizable monomers may be used alone or in combination of two or more. The amount of the other copolymerizable monomer may be appropriately selected depending on the intended purpose and application, and is not particularly limited. For example, 20% by weight or less (for example, 2 to 20% by weight) of the total monomer raw material of the acrylic polymer. Typically, it is preferably 3 to 10% by weight).

In a preferred embodiment, the monomer raw material preferably has a total ratio of alkoxyalkyl (meth) acrylate and alkoxypolyalkylene glycol (meth) acrylate limited to less than 20% by weight from the viewpoint of suppressing gelation. The total proportion of the alkoxyalkyl (meth) acrylate and the alkoxypolyalkylene glycol (meth) acrylate is more preferably less than 10% by weight, further preferably less than 3% by weight, particularly preferably less than 1% by weight, in one embodiment. The monomer raw material is substantially free of alkoxyalkyl (meth) acrylate and alkoxypolyalkylene glycol (meth) acrylate (content 0 to 0.3% by weight).
Similarly, in one embodiment, the monomer raw material may or may not contain an alkoxy group-containing monomer in a proportion of less than 20% by weight. The amount of the alkoxy group-containing monomer in the monomer raw material is preferably less than 10% by weight, more preferably less than 3% by weight, still more preferably less than 1% by weight, and in a particularly preferable aspect, the monomer raw material has an alkoxy group. It contains substantially no monomer (content 0 to 0.3% by weight).

The method for polymerizing the monomer raw material is not particularly limited, and various polymerization methods known as synthetic polymers of acrylic polymers such as a solution polymerization method, an emulsion polymerization method, a massive polymerization method, and a suspension polymerization method are appropriately adopted. be able to. For example, a solution polymerization method can be preferably adopted. As a monomer supply method for solution polymerization, a batch charging method, a continuous supply (dropping) method, a divided feeding (dropping) method, or the like in which all the monomer raw materials are supplied at once can be appropriately adopted. The solvent (polymerization solvent) used for solution polymerization can be appropriately selected from conventionally known organic solvents. For example, 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; 1,2- Alkane halides such as dichloroethane; lower alcohols such as isopropyl alcohol (for example, monohydric alcohols having 1 to 4 carbon atoms); ethers such as tert-butyl methyl ether; ketones such as methyl ethyl ketone; etc. Any one solvent or a mixed solvent of two or more can be used. The polymerization temperature can be appropriately selected depending on the type of monomer and solvent used, the type of polymerization initiator, etc., and may be, for example, about 20 ° C. to 120 ° C. (typically 40 ° C. to 80 ° C.). it can. By solution polymerization, a polymerization reaction solution in which the polymer of the monomer raw material is dissolved in the polymerization solvent can be obtained. The pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer can be preferably produced by using the above-mentioned polymerization reaction solution.

In the polymerization, a known or commonly used thermal polymerization initiator or photopolymerization initiator may be used depending on the polymerization method, polymerization mode and the like. Examples of the thermal polymerization initiator include an azo-based polymerization initiator, a peroxide-based initiator, a redox-based initiator obtained by combining a peroxide and a reducing agent, a substituted ethane-based initiator, and the like. Examples of photopolymerization initiators include α-ketor photoinitiators, acetophenone photoinitiators, benzoin ether photoinitiators, ketal photoinitiators, aromatic sulfonyl chloride photoinitiators, photoactive oxime photoinitiators. Examples thereof include an initiator, a benzophenone-based photoinitiator, a thioxanthone-based photoinitiator, and an acylphosphinoxide-based photoinitiator. As the polymerization initiator, one type may be used alone or two or more types may be used in combination as appropriate.

The amount of the polymerization initiator used may be a normal amount, for example, about 0.005 to 1 part by weight (typically 0.01 to 1 part by weight) with respect to 100 parts by weight of the total monomer raw material. You can choose from a range.

For the above polymerization, various conventionally known chain transfer agents (which can also be grasped as a molecular weight adjuster or a degree of polymerization adjuster) can be used, if necessary. As the chain transfer agent, mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, thioglycolic acid, and α-thioglycerol can be used. Alternatively, a chain transfer agent containing no sulfur atom (non-sulfur chain transfer agent) may be used. Specific examples of the non-sulfur chain transfer agent include anilins such as N, N-dimethylaniline and N, N-diethylaniline; terpenoids such as α-pinene and turpinolene; α-methylstyrene and α-methylstyrene dimer. Such as styrenes; compounds having a benzylidenyl group such as dibenzylidene acetone, cinnamyl alcohol, cinnamyl aldehyde; hydroquinones such as hydroquinone and naphthohydroquinone; quinones such as benzoquinone and naphthoquinone; 2,3-dimethyl-2-butene , 1,5-Cyclooctadiene and the like; alcohols such as phenol, benzyl alcohol and allyl alcohol; benzyl hydrogens such as diphenylbenzene and triphenylbenzene; and the like.
The chain transfer agent may be used alone or in combination of two or more. When a chain transfer agent is used, the amount used can be, for example, about 0.01 to 1 part by weight with respect to 100 parts by weight of the monomer raw material. The techniques disclosed herein may also be preferably practiced in aspects that do not use chain transfer agents.

The molecular weight of the acrylic polymer is not particularly limited and can be set in an appropriate range according to the required performance. The weight average molecular weight (Mw) of an acrylic polymer is usually about 10 × 10 ⁴ or more (for example, 20 × 10 ^{4 or more), and is more than 30 × 10 4} from the viewpoint of achieving a good balance between cohesive force and adhesive force. and it is appropriate to, is preferably about 40 × 10 ⁴ or more, may be approximately 50 × 10 ⁴ or more, may be approximately 55 × 10 ⁴ or more. The upper limit of Mw of the acrylic polymer is not particularly limited. From the viewpoint of coatability of the pressure-sensitive adhesive composition, the Mw of the acrylic polymer, usually suitably be at about 500 × 10 ⁴ or less, for example may be at about 0.99 × 10 ⁴ or less, approximately 75 × 10 ⁴ may be less. The Mw may be the Mw of the acrylic polymer in either the pressure-sensitive adhesive composition or the pressure-sensitive adhesive layer.
Here, Mw refers to a standard polystyrene-equivalent value obtained by gel permeation chromatography (GPC). As the GPC apparatus, for example, a model name "HLC-8320GPC" (column: TSKgelGMH-H (S), manufactured by Tosoh Corporation) can be used. The same applies to the examples described later.

The acrylic pressure-sensitive adhesive layer may further contain a polymer other than the acrylic polymer as a subpolymer, if necessary. As the above-mentioned subpolymer, among various polymers exemplified as polymers that can be contained in the pressure-sensitive adhesive layer, those other than the acrylic polymer can be mentioned as a preferable example. When the pressure-sensitive adhesive layer disclosed herein is an acrylic pressure-sensitive adhesive layer containing a subpolymer in addition to the acrylic polymer, the content of the subpolymer is less than 100 parts by weight with respect to 100 parts by weight of the acrylic polymer. It is appropriate, preferably 50 parts by weight or less, more preferably 30 parts by weight or less, and further preferably 10 parts by weight or less. The content of the subpolymer may be 5 parts by weight or less with respect to 100 parts by weight of the acrylic polymer, or may be 1 part by weight or less. The technique disclosed herein can be preferably carried out, for example, in an embodiment in which 99.5 to 100% by weight of the polymer contained in the pressure-sensitive adhesive layer is an acrylic polymer.

(Adhesive layer other than acrylic)
The pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive surface in the pressure-sensitive adhesive sheet disclosed herein may be a pressure-sensitive adhesive layer using a polymer other than the acrylic-based polymer as a base polymer, that is, a pressure-sensitive adhesive layer other than the acrylic-based polymer. The non-acrylic pressure-sensitive adhesive layer may further contain a subpolymer other than the base polymer in addition to the base polymer, if necessary. In this case, the content of the subpolymer in the non-acrylic pressure-sensitive adhesive layer can be selected from the above-mentioned contents exemplified as the content of the subpolymer in the acrylic pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer other than the acrylic-based adhesive layer may be a pressure-sensitive adhesive layer containing an acrylic-based polymer as a secondary polymer.

(Glass-transition temperature)
The glass transition temperature (Tg) of the base polymer (for example, an acrylic polymer) of the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive surface is preferably about 15 ° C. or lower. In some embodiments, the Tg is preferably 10 ° C. or lower, and is 0 ° C. or lower, from the viewpoint of adhesion to the adherend (for example, followability to the surface shape of the adherend). It may be −10 ° C. or lower, −20 ° C. or lower, −30 ° C. or lower, or −40 ° C. or lower. Further, from the viewpoint of the cohesiveness of the pressure-sensitive adhesive and the ease of light peeling due to water peeling, the Tg of the base polymer may be, for example, −75 ° C. or higher, −60 ° C. or higher, or −55 ° C. or higher.

Here, the glass transition temperature (Tg) of the polymer in the present specification means the glass transition temperature obtained by the Fox formula based on the composition of the monomer raw material constituting the polymer. As shown below, the Fox formula is a relational formula between the Tg of the copolymer and the glass transition temperature Tgi of the homopolymer in which each of the monomers constituting the copolymer is homopolymerized.
1 / Tg = Σ (Wi / Tgi)
In the Fox formula, Tg is the glass transition temperature (unit: K) of the copolymer, Wi is the weight fraction of the monomer i in the copolymer (copolymerization ratio based on the weight), and Tgi is the monomer i. Represents the glass transition temperature (unit: K) of the homopolymer.

As the glass transition temperature of the homopolymer used for calculating Tg, the value described in publicly known materials shall be used. For example, for the monomers listed below, the following values are used as the glass transition temperature of the homopolymer of the monomer.
2-Ethylhexyl acrylate-70 ° C
n-Butyl acrylate -55 ° C
Isostearyl acrylate -18 ° C
Methyl methacrylate 105 ° C
Methyl acrylate 8 ℃
Ethyl acrylate-22 ° C
N-Vinyl-2-pyrrolidone 54 ° C
N-Acryloyl Morpholine 145 ° C
2-Hydroxyethyl acrylate -15 ° C
4-Hydroxybutyl acrylate-40 ° C
Acrylic acid 106 ℃
Methacrylic acid 228 ° C

For the glass transition temperature of homopolymers of monomers other than those exemplified above, the numerical values described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) shall be used. When multiple types of values are described in this document, the highest value is adopted.

For the monomer in which the glass transition temperature of the homopolymer is not described in the Polymer Handbook, the value obtained by the following measurement method shall be used (see JP-A-2007-51271). Specifically, in a reactor equipped with a thermometer, a stirrer, a nitrogen introduction tube and a reflux condenser, 100 parts by weight of a monomer, 0.2 parts by weight of azobisisobutyronitrile and 200 parts by weight of ethyl acetate as a polymerization solvent were added. Add and stir for 1 hour while circulating nitrogen gas. After removing oxygen in the polymerization system in this way, the temperature is raised to 63 ° C. and the reaction is carried out for 10 hours. Then, the mixture is cooled to room temperature to obtain a homopolymer solution having a solid content concentration of 33% by weight. Next, this homopolymer solution is cast-coated on a release liner and dried to prepare a test sample (sheet-shaped homopolymer) having a thickness of about 2 mm. This test sample is punched into a disk shape with a diameter of 7.9 mm, sandwiched between parallel plates, and subjected to shear strain at a frequency of 1 Hz using a viscoelasticity tester (ARES, manufactured by Leometrics) in a temperature range of −70 to 150 ° C. The viscoelasticity is measured in a shear mode at a heating rate of 5 ° C./min, and the peak top temperature of tan δ is defined as Tg of the homopolymer.

(Compound A)
The pressure-sensitive adhesive layer may contain a heat-resistant release agent, if necessary. As the heat-resistant release agent, at least one compound A selected from the group consisting of a surfactant and a compound having a polyoxyalkylene skeleton is used. By incorporating such a heat-resistant release agent in the pressure-sensitive adhesive layer, the effect of suppressing an event in which the release force of the pressure-sensitive adhesive sheet increases due to high-temperature exposure can be exhibited. For example, by incorporating a heat-resistant release agent to the adhesive layer, usually peel force _Fd a, Fd _b and water release force _Fw a, it may reduce at least one Fw _b. Although the reason for obtaining such an effect is not particularly limited, it is generally found on the surface of the pressure-sensitive adhesive layer where the adhesion between the adherend and the pressure-sensitive adhesive layer can be promoted by high-temperature exposure and the peeling force can be increased. The presence of the heat-resistant release agent suppresses the increase in the release force, and the surfactant and the compound having a polyoxyalkylene skeleton used as the heat-resistant release agent all have a hydrophilic region, thereby adhering. Since it tends to be appropriately unevenly distributed on the surface of the agent layer, it is considered that the increase in the peeling force is effectively suppressed. Further, the heat-resistant release agent has a hydrophilic region as described above and tends to be appropriately unevenly distributed on the surface of the pressure-sensitive adhesive layer, so that it can also be useful as a water release additive that promotes light release by water release.

As the compound having a surfactant and a polyoxyalkylene skeleton, one or more of known surfactants and compounds having a polyoxyalkylene skeleton can be used without particular limitation. Compound A is typically preferably contained in the pressure-sensitive adhesive layer in free form. Needless to say, some of the above-mentioned surfactants have a compound having a polyoxyalkylene skeleton, and vice versa.

As the surfactant that can be used as compound A, known nonionic surfactants, anionic surfactants, cationic surfactants and the like can be used. Of these, nonionic surfactants are preferable. The surfactant may be used alone or in combination of two or more.

Examples of nonionic surfactants are polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene octylphenyl ether, polyoxy. Polyoxyethylene alkyl phenyl ethers such as ethylene nonylphenyl ether; polyoxyethylene fatty acid esters such as polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate; sorbitan monolaurate, sorbitan monopalmitate , Solbitan monostearate, sorbitan fatty acid esters such as sorbitan monooleate; polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxy Polyoxyethylene sorbitan fatty acid esters such as ethylene sorbitan triisostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate; polyoxyethylene glyceryl ether fatty acid esters; polyoxyelene-polyoxypropylene block copolymers; etc. Can be mentioned. Nonionic surfactants include reactive surfactants having radically polymerizable functional groups such as propenyl group, (meth) allyl group, vinyl group and (meth) acryloyl group (eg, polyoxyethylene nonylpropenylphenyl ether and the like). , Nonionic reactive surfactant). These nonionic surfactants can be used alone or in combination of two or more. From the viewpoint of preferably exerting the effect of the compound A being appropriately unevenly distributed on the surface of the pressure-sensitive adhesive layer and enhancing the performance stability of the pressure-sensitive adhesive sheet, it does not have the above-mentioned radically polymerizable functional group (non-reactive). ) A nonionic surfactant can be preferably adopted.

Examples of anionic surfactants include alkylbenzene sulfonates such as nonylbenzene sulfonate, dodecylbenzene sulfonate (eg sodium dodecylbenzene sulfonate); lauryl sulfate (eg sodium lauryl sulfate, ammonium lauryl sulfate), etc. Alkyl sulfate such as octadecyl sulfate; fatty acid salt; polyoxyethylene alkyl ether sulfate such as polyoxyethylene octadecyl ether sulfate and polyoxyethylene lauryl ether sulfate (for example, sodium polyoxyethylene alkyl ether sulfate), polyoxy Polyoxyethylene alkyl phenyl ether sulfate such as ethylene lauryl phenyl ether sulfate (for example, sodium polyoxyethylene alkyl phenyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, etc.), polyoxyethylene styrene phenyl ether sulfate, etc. Polyether sulfate; polyoxyethylene alkyl ether phosphate such as polyoxyethylene stearyl ether phosphate, polyoxyethylene lauryl ether phosphate, etc .; sodium salt, potassium salt, etc. of the above polyoxyethylene alkyl ether phosphate, etc. Polyoxyethylene alkyl ether phosphate ester salts; sulfosuccinates such as lauryl sulfosuccinate, polyoxyethylene lauryl sulfosuccinate (eg, sodium polyoxyethylene alkyl sulfosuccinate); polyoxyethylene alkyl ether acetate; etc. Can be mentioned. When the anionic surfactant forms a salt, the salt may be, for example, a metal salt such as a sodium salt, a potassium salt, a calcium salt or a magnesium salt (preferably a monovalent metal salt), an ammonium salt, an amine salt or the like. Can be. The anionic surfactant may be used alone or in combination of two or more. From the same viewpoint as the nonionic surfactant, a non-reactive anionic surfactant can be preferably adopted.

Examples of cationic surfactants include polyether amines such as polyoxyethylene lauryl amine and polyoxyethylene stearyl amine. The cationic surfactant may be used alone or in combination of two or more.

Examples of the compound having a polyoxyalkylene skeleton that can be used as compound A include polyalkylene glycols such as polyethylene glycol (PEG) and polypropylene glycol (PPG); polyethers containing polyoxyethylene units, and polyoxypropylene units. Compounds containing polyethers, oxyethylene units and oxypropylene units (the sequences of these units may be random or block-like); derivatives thereof; and the like can be used. Further, among the above-mentioned nonionic, anionic and cationic surfactants, compounds having a polyoxyalkylene skeleton can also be used. These can be used alone or in combination of two or more. Among them, it is preferable to use a compound containing a polyoxyethylene skeleton (also referred to as a polyoxyethylene segment), and PEG is more preferable.

The molecular weight (chemical formula) of the compound having a polyoxyalkylene skeleton (for example, polyethylene glycol) is not particularly limited. From the viewpoint of uniform mixing, it is suitable, for example, less than 1000, and preferably about 600 or less (for example, 500 or less). The lower limit of the molecular weight of the compound having a polyoxyalkylene skeleton (for example, polyethylene glycol) is not particularly limited, and a compound having a molecular weight of about 100 or more (for example, about 200 or more, further about 300 or more) is preferably used.

The pressure-sensitive adhesive layer containing compound A is typically formed from a pressure-sensitive adhesive composition containing the compound A. The pressure-sensitive adhesive composition containing Compound A can be preferably prepared by a method comprising adding Compound A in the form of no solvent or in the form of an organic solvent solution. The solvent-free form refers to a form that is not diluted with an organic solvent or water that does not form a pressure-sensitive adhesive layer, and may be, for example, a form composed of compound A. The organic solvent used for preparing the organic solvent solution can be appropriately selected from conventionally known organic solvents. Specific examples of such an organic solvent include the same solvents as those used for solution polymerization described later. Preferable examples include a mixed solvent containing ethyl acetate and ethyl acetate (which may be a mixed solvent of ethyl acetate and toluene), and a mixed solvent containing toluene and toluene. For example, a mixed solvent containing ethyl acetate or ethyl acetate as a main component can be preferably adopted. The solvent-based or active energy ray-curable pressure-sensitive adhesive composition is substantially water-free in some embodiments (eg, 100 parts by weight of Compound A) from the viewpoint of preventing water from being brought into the pressure-sensitive adhesive composition. It is preferred that Compound A be added in the form of an organic solvent solution (with a water content of less than 10 parts by weight or less than 5 parts by weight or less than 1 part by weight). As a result, a more homogeneous pressure-sensitive adhesive layer can be formed.

In some embodiments, as the compound A, a nonionic compound is preferably used because it can be easily blended into the pressure-sensitive adhesive composition with good uniformity. According to the pressure-sensitive adhesive composition in which the compound A is uniformly blended, a pressure-sensitive adhesive layer in which the compound A is uniformly present on the surface tends to be formed. This is preferable from the viewpoint of allowing the adhesive sheet to be peeled off from the adherend more smoothly and reducing the load on the adherend due to fluctuations in the peeling force (for example, vibration or impact accompanying the fluctuations).

The HLB of compound A is not particularly limited. 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, 6 or more, 8 or more, or 9 or more. As a result, water releasability tends to be preferably exhibited. The HLB of compound A is more preferably 10 or more, still more preferably 11 or more, still more preferably 12 or more, particularly preferably 13 or more, and may be 14 or more, 15 or more, or even 16 or more. According to the compound A having an HLB in the above range, the light exfoliation property due to water exfoliation can be more effectively exhibited. The upper limit of the HLB is 20 or less, and may be 18, for example. In some embodiments, the HLB of compound A may be 16 or less, for example 15 or less, for example in terms of compatibility.

The HLB in the present specification is a Hydrophilic-Lipophile Balance by Griffin, which is a value indicating the degree of affinity of the surfactant with water or oil, and the ratio of hydrophilicity to lipophilicity is between 0 and 20. It is expressed by the numerical value of. The definition of HLB is W. C. Griffin: J. Soc. Cosmetic Chemists, 1,311 (1949), Koshimitsu Takahashi, Yoshiro Namba, Motoo Koike, Masao Kobayashi, "Surfactant Handbook", 3rd Edition, Kogaku Shosha Publishing, November 25, 1972, p179- As described in 182 and the like. The compound A having the above HLB can be selected based on the common general technical knowledge of those skilled in the art by referring to the above references as necessary.

In some correspondences, the compound A preferably has 2 or more hydroxyl groups in one molecule, and more preferably has 3 or more hydroxyl groups in one molecule, from the viewpoint of affinity with the aqueous stripping solution. .. Examples of compound A having 2 or 3 or more hydroxyl groups in one molecule include sorbitan monoester, polyoxyalkylene sorbitan monoester, polyoxyalkylene glyceryl ether, polyoxyalkylene diglyceryl ether, polyoxyalkylene glyceryl ether monoester and the like. Can be mentioned. The upper limit of the number of hydroxyl groups contained in one molecule of compound A is not particularly limited, but it is usually appropriate to be 10 or less from the viewpoint of solubility in an organic solvent and ease of preparation of a pressure-sensitive adhesive composition. It is preferably 8 or less, 6 or less, or 4 or less.

In some correspondences, as the compound A, a nonionic compound having a fatty acid ester structure can be preferably selected from the viewpoint of solubility in an organic solvent (for example, esters such as ethyl acetate). Compound A having a fatty acid ester structure can also be advantageous in terms of compatibility in the pressure-sensitive adhesive layer. For example, as the compound A to be contained in the acrylic pressure-sensitive adhesive layer, a compound having a fatty acid ester structure can be preferably adopted. Examples of nonionic compounds having a fatty acid ester structure include sorbitan fatty acid ester, polyoxyalkylene fatty acid ester, polyoxyalkylene fatty acid monoester and the like.

In some embodiments, the compound A is preferably in the form of 100% solid content and is liquid at room temperature (25 ° C. in this case) from the viewpoint of ease of preparation of the organic solvent solution.
Further, in some embodiments, the compound A is preferably one that dissolves without phase separation in Test II below, and more preferably one that dissolves without phase separation in Test I below. The following tests I and II shall be carried out in an environment of room temperature (23 to 25 ° C.) using compound A in the form of 100% solid content.
[Test I]
90 g of ethyl acetate and 10 g of compound A are placed in a container having a capacity of 200 ml (mL), stirred for 1 minute using a glass rod, allowed to stand, and visually observed for phase separation after 5 minutes.
[Test II]
90 g of ethyl acetate and 10 g of compound A are placed in a container having a capacity of 200 mL, stirred for 1 minute using a glass rod, treated at 35 kHz for 10 minutes using an ultrasonic disperser, and further stirred for 1 minute using a glass rod. After 5 minutes, visually observe the presence or absence of phase separation.
As the ultrasonic disperser, a model name "ULTRASONIC CLEANER" manufactured by AS ONE or an equivalent product thereof can be used.

The amount of compound A used is not particularly limited, and the effect of use according to the purpose (for example, one or both of an effect of suppressing an increase in peeling force due to high temperature exposure and an effect of promoting light peeling due to water peeling). Can be set so that is properly exhibited. In some embodiments, the amount of Compound A used may be, for example, approximately 5 parts by weight or less relative to 100 parts by weight of the base polymer, such as bonding reliability and water resistance to the adherend at a stage not intended for peeling. From the viewpoint of reliability, it is appropriate 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, and 0.6 parts by weight. It may be less than 0.4 parts by weight, less than 0.2 parts by weight, or less than 0.1 parts by weight. Compound A having a high HLB (for example, 5 or more, preferably 10 or more) tends to exhibit good water peelability even when added in a small amount. Further, the amount of the compound A with respect to 100 parts by weight of the base polymer can be, for example, 0.001 part by weight or more, and the compound A is uniformly present on the surface of the pressure-sensitive adhesive layer so that the pressure-sensitive adhesive sheet can be peeled off from the adherend. From the viewpoint of smoother progress, it is usually appropriate to set the amount to 0.01 parts by weight or more, preferably 0.03 parts by weight or more (for example, 0.1 parts by weight or more). In a composition that emphasizes water releasability, the amount of compound A with respect to 100 parts by weight of the base polymer may be 0.3 parts by weight or more (for example, 0.5 parts by weight or more).

(Crosslinking agent)
A cross-linking agent may be used for the pressure-sensitive adhesive layer, if necessary, for the purpose of adjusting the cohesive force and the like. The cross-linking agent may be contained in the pressure-sensitive adhesive layer in the form after the cross-linking reaction, or may be contained in the form before the cross-linking reaction. The type of the cross-linking agent is not particularly limited, and is selected from the conventionally known cross-linking agents so that the cross-linking agent exhibits an appropriate cross-linking function in the pressure-sensitive adhesive layer, for example, depending on the composition of the pressure-sensitive adhesive composition. be able to. Examples of the cross-linking agent that can be used include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, carbodiimide-based cross-linking agents, melamine-based cross-linking agents, urea-based cross-linking agents, metal alkoxide-based cross-linking agents, and metals. Examples thereof include a chelate-based cross-linking agent, a metal salt-based cross-linking agent, a hydrazine-based cross-linking agent, and an amine-based cross-linking agent. These can be used alone or in combination of two or more. In some preferred embodiments, at least an isocyanate-based crosslinker is used as the crosslinker. An isocyanate-based cross-linking agent and another cross-linking agent (for example, an epoxy-based cross-linking agent) may be used in combination.

As the isocyanate-based cross-linking agent, a polyfunctional isocyanate compound having two or more functionalities can be used. For example, aromatic isocyanates such as tolylene diisocyanate, xylene diisocyanate, polymethylene polyphenyl diisocyanate, tris (p-isocyanatophenyl) thiophosphate, diphenylmethane diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; aliphatic isocyanates such as hexamethylene diisocyanate. Isocyanate; etc. Commercially available products include trimethylolpropane / tolylene diisocyanate adduct (manufactured by Toso Co., Ltd., trade name "Coronate L") and trimethylolpropane / hexamethylene diisocyanate adduct (manufactured by Toso Co., Ltd., trade name "Coronate L"). Examples thereof include isocyanate adducts such as "Coronate HL") and isocyanurates of hexamethylene diisocyanate (manufactured by Toso Co., Ltd., trade name "Coronate HX").

As the epoxy-based cross-linking agent, one having two or more epoxy groups in one molecule can be used without particular limitation. An epoxy-based cross-linking agent having 3 to 5 epoxy groups in one molecule is preferable. Specific examples of the epoxy-based cross-linking agent include N, N, N', N'-tetraglycidyl-m-xylene diamine, 1,3-bis (N, N-diglycidyl aminomethyl) cyclohexane, and 1,6-hexane. Examples thereof include diol diglycidyl ether, polyethylene glycol diglycidyl ether, and polyglycerol polyglycidyl ether. Commercially available epoxy cross-linking agents include Mitsubishi Gas Chemical's product names "TETRAD-X" and "TETRAD-C", DIC's product name "Epicron CR-5L", and Nagase ChemteX's products. Examples thereof include the name "Denacol EX-512" and the product name "TEPIC-G" manufactured by Nissan Chemical Industries, Ltd.

As the oxazoline-based cross-linking agent, those having one or more oxazoline groups in one molecule can be used without particular limitation.
Examples of the aziridine-based cross-linking agent include trimethylolpropane tris [3- (1-aziridinyl) propionate], trimethylolpropane tris [3- (1- (2-methyl) aziridinyl propionate)], and the like. Be done.
As the carbodiimide-based cross-linking agent, a low molecular weight compound or a high molecular weight compound having two or more carbodiimide groups can be used.

The metal chelate-based cross-linking agent can typically have a structure in which a polyvalent metal is covalently or coordinated to an organic compound. Examples of the polyvalent metal atom include Al, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Ba, Mo, La, Sn, Ti and the like. Of these, Al, Zr, and Ti are preferable. Examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, and a ketone compound. The metal chelate-based cross-linking agent can typically be a compound having a structure in which an oxygen atom in the organic compound is bonded (covalent bond or coordinate bond) to the polyvalent metal.

Peroxides may be used as the cross-linking agent in some embodiments. Peroxides include di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, and t-butylperoxyneodecanoate. , T-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxyisobutyrate, di Examples thereof include benzoyl peroxide. Among these, peroxides having particularly excellent cross-linking reaction efficiency include di (4-t-butylcyclohexyl) peroxydicarbonate, dilauroyl peroxide, dibenzoyl peroxide and the like. When a peroxide is used as the polymerization initiator, the peroxide remaining without being used in the polymerization reaction can also be used in the crosslinking reaction. In that case, the residual amount of peroxide may be quantified, and if the ratio of peroxide is less than a predetermined amount, the peroxide may be added so as to be a predetermined amount, if necessary. The quantification of peroxide can be carried out by the method described in Japanese Patent No. 4971517.

The amount of the cross-linking agent used (when two or more cross-linking agents are used, the total amount thereof) is not particularly limited, and can be appropriately set so as to obtain a desired effect of use. The amount of the cross-linking agent used with respect to 100 parts by weight of the base polymer (for example, acrylic polymer) is usually about 0.01 part by weight or more from the viewpoint of preventing adhesive residue and suppressing an increase in peeling force due to high temperature exposure after application. It is appropriate, preferably about 0.1 parts by weight or more, more preferably about 0.5 parts by weight or more, about 1.0 part by weight or more, or about 1.5 parts by weight or more. It may be about 2.0 parts by weight or more.
Further, it is usually appropriate that the amount of the cross-linking agent used with respect to 100 parts by weight of the base polymer is about 15 parts by weight or less, and from the viewpoint of adhesion to the adherend during semiconductor processing, bonding reliability and the like, it is appropriate. It is preferably about 12 parts by weight or less, more preferably about 10 parts by weight or less. In some embodiments where the initial normal peeling force Fd ₀ is more important, the amount of the cross-linking agent used per 100 parts by weight of the base polymer may be, for example, less than 7.0 parts by weight or less than 5.0 parts by weight. It may be less than 4.0 parts by weight or less than 3.0 parts by weight. In an embodiment containing a certain amount of compound A (for example, more than 0.2 parts by weight with respect to 100 parts by weight of the base polymer), the fact that the amount of the cross-linking agent used is not too large means that compound A is excessive on the surface of the pressure-sensitive adhesive layer. It can also be advantageous from the viewpoint of suppressing a decrease in the initial normal peeling force Fd _{0 due to uneven distribution.}

In the embodiment in which the isocyanate-based cross-linking agent is used as the cross-linking agent, the amount of the isocyanate-based cross-linking agent used with respect to 100 parts by weight of the base polymer is usually set from the viewpoint of preventing adhesive residue and suppressing an increase in peeling force due to high temperature exposure after application. It is appropriate that the amount is about 0.1 part by weight or more, preferably about 0.5 part by weight or more, more preferably about 0.7 part by weight or more, and about 1.0 part by weight or more, and about 1.0 part by weight or more. It may be 1.5 parts by weight or more.
Further, it is usually appropriate that the amount of the isocyanate-based cross-linking agent used with respect to 100 parts by weight of the base polymer is about 15 parts by weight or less, and from the viewpoint of adhesion to the adherend and bonding reliability during semiconductor processing, etc. Therefore, it is preferably about 12 parts by weight or less, more preferably about 10 parts by weight or less, and may be less than 7.0 parts by weight, less than 5.0 parts by weight, or less than 4.0 parts by weight. It may be less than 0 parts by weight or less than 2.5 parts by weight.

In a mode in which an epoxy-based cross-linking agent is used as the cross-linking agent (a mode in which an isocyanate-based cross-linking agent and an epoxy-based cross-linking agent are used in combination), the amount of the epoxy-based cross-linking agent used with respect to 100 parts by weight of the base polymer is determined after application. From the viewpoint of suppressing the increase in peeling force due to high temperature exposure, it is usually appropriate to set the amount to about 0.01 part by weight or more, preferably about 0.05 part by weight or more, and more preferably about 0.1 part by weight or more. It may be about 0.3 parts by weight or more, and may be about 0.5 parts by weight or more. In a preferred embodiment, the amount of the epoxy-based cross-linking agent used with respect to 100 parts by weight of the base polymer may be, for example, more than 0.5 parts by weight, and may be 0.6 parts by weight or more.
Further, it is usually appropriate that the amount of the epoxy-based cross-linking agent used with respect to 100 parts by weight of the base polymer is about 5 parts by weight or less from the viewpoint of adhesion to the adherend during semiconductor processing, bonding reliability, and the like. Yes, preferably about 3 parts by weight or less, more preferably about 2 parts by weight or less, 1.5 parts by weight or less, or 1.0 part by weight or less.

When used in combination with an isocyanate-based crosslinking agent and an epoxy crosslinking agent, the ratio of the amount W _EPO of epoxy crosslinking agent to the amount W _NCO of isocyanate crosslinking agent (weight ratio W _EPO: W _NCO), for example It can be 0.005: 1 or more and 2: 1 or less, and usually 0.01: 1 or more and 1: 1 or less is appropriate, and it is more than 0.10: 1 and 0.80: 1 or less. It is preferably more than 0.25: 1 and 0.60: 1 or less (for example, 0.30: 1 or more and 0.50: 1 or less).

A cross-linking catalyst may be used to allow the cross-linking reaction to proceed more effectively. Examples of the cross-linking catalyst include metal-based cross-linking catalysts such as tetra-n-butyl titanate, tetraisopropyl titanate, ferric nasem, butyl tin oxide, and dioctyl tin dilaurate. Of these, tin-based cross-linking catalysts such as dioctyl tin dilaurate are preferable. The amount of the cross-linking catalyst used is not particularly limited. The amount of the cross-linking catalyst used with respect to 100 parts by weight of the base polymer may be, for example, approximately 0.0001 parts by weight or more and 1 part by weight or less, 0.001 parts by weight or more and 0.1 parts by weight or less, and 0.005 parts by weight or more. It may be 0.5 parts by weight or less.

(Other optional ingredients)
The pressure-sensitive adhesive layer may contain, if necessary, a pressure-imparting resin (for example, a rosin-based, petroleum-based, terpen-based, phenol-based, ketone-based, etc. pressure-imparting resin), a viscosity modifier (for example, a thickener), and a leveling agent. , Plasticizers, fillers, colorants such as pigments and dyes, stabilizers, preservatives, antioxidants, antioxidants, and various other additives that are common in the field of adhesives, as other optional ingredients. Can be included. As for such various additives, conventionally known ones can be used by a conventional method and do not particularly characterize the present invention, and thus detailed description thereof will be omitted.
In some embodiments, the pressure-sensitive adhesive layer is used from the viewpoint of achieving a good balance between adhesion to an adherend during semiconductor processing and peelability during removal of the adherend (for example, peelability due to water peeling). The content of the tackifier resin can be, for example, less than 5 parts by weight, further less than 3 parts by weight, less than 1 part by weight, or less than 0.5 parts by weight with respect to 100 parts by weight of the base polymer. It may be less than 0.1 parts by weight. The pressure-sensitive adhesive layer may be substantially free of the tack-imparting resin (for example, the content of the pressure-sensitive adhesive layer with respect to 100 parts by weight of the base polymer is 0 to 0.05 parts by weight).

In some preferred embodiments, the pressure-sensitive adhesive layer may have a composition in which the content of the polymer (typically the base polymer) accounts for approximately 80% by weight or more of the total weight of the pressure-sensitive adhesive layer. As a result, the effect of applying water peeling to reduce the peeling force (light peeling effect) can be preferably realized. From such a viewpoint, the content of the polymer is preferably about 85% by weight or more, more preferably about 90% by weight or more, and may be about 92% by weight or more based on the total weight of the pressure-sensitive adhesive layer. , It may be about 95% by weight or more, and may be about 98% by weight or more.

In some other aspects of the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive sheet is composed of an active energy ray (preferably ultraviolet) curable pressure-sensitive adhesive layer, that is, an active energy ray-curable pressure-sensitive adhesive layer. It may have an adhesive surface. The active energy ray-curable pressure-sensitive adhesive layer is based on, for example, an active energy ray-curable polymer (for example, an acrylic polymer) having a curable functional group at at least one of a side chain, a main chain and a terminal of the main chain. It can be a pressure-sensitive adhesive layer contained as a polymer. Another example of the active energy ray-curable pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer containing a monomer or oligomer having two or more curable functional groups in the molecule. Examples of the polymers, monomers and oligomers that can be used to make the pressure-sensitive adhesive layer ray-curable include functional groups having a carbon-carbon double bond (eg, (meth) acryloyl group, vinyl group, etc.). Polymers on the side chains, polyfunctional (meth) acrylates (eg, trimethylolpropantri (meth) acrylates, pentaerythritol tri (meth) acrylates, dipentaerythritol hexa (meth) acrylates, 1,6-hexanedioldi (meth) ) Acrylate, etc.), isocyanate-based compounds having a carbon-carbon double bond (for example, 2-isocyanatoethyl (meth) acrylate, m-isopropenyl-α, α-dimethylbenzyl isocyanate, etc.), urethane oligomer, urethane (meth) ) Acrylate and the like can be mentioned, but the present invention is not limited to these. The active energy ray-curable pressure-sensitive adhesive layer may contain a known photoinitiator, if necessary.

The pressure-sensitive adhesive sheet disclosed herein preferably has a pressure-sensitive adhesive surface composed of a pressure-sensitive adhesive layer (non-active energy ray-curable pressure-sensitive adhesive layer) having no active energy ray-curable property. The pressure-sensitive adhesive sheet having an adhesive surface composed of a non-active energy ray-curable pressure-sensitive adhesive layer has good performance stability against irradiation with active energy rays (ultraviolet rays, etc.), and is used including a semiconductor processing process involving irradiation with active energy rays. It can also be preferably applied to aspects.

<Formation of adhesive layer>
The pressure-sensitive adhesive layer constituting the pressure-sensitive surface of the pressure-sensitive adhesive sheet disclosed herein is a pressure-sensitive adhesive formed from a pressure-sensitive adhesive composition containing a base polymer (for example, an acrylic polymer) and optionally other optional components. Can be a layer. The pressure-sensitive adhesive composition is a solvent-type pressure-sensitive adhesive composition in which a pressure-sensitive adhesive (adhesive component) is contained in an organic solvent, and is prepared so as to be cured by active energy rays such as ultraviolet rays and radiation to form a pressure-sensitive adhesive. Active energy ray-curable pressure-sensitive adhesive composition, water-dispersed pressure-sensitive adhesive composition in which the pressure-sensitive adhesive is dispersed in water, hot-melt type pressure-sensitive adhesive that is applied in a heat-melted state and forms a pressure-sensitive adhesive when cooled to around room temperature. It can be in various forms such as a composition. The active energy curable pressure-sensitive adhesive composition typically exhibits fluidity that can be applied at room temperature (approximately 0 ° C. to 40 ° C., for example, about 25 ° C.), and is cured by irradiation with active energy. It is a liquid composition that forms a pressure-sensitive adhesive (viscoelastic body).
The pressure-sensitive adhesive sheet according to some aspects may have a structure having a pressure-sensitive adhesive layer formed by using a solvent-type pressure-sensitive adhesive composition or an active energy ray-curable pressure-sensitive adhesive composition. In the embodiment in which the pressure-sensitive adhesive layer contains compound A, a solvent-type pressure-sensitive adhesive composition can be preferably adopted from the viewpoint of ease of preparation of the pressure-sensitive adhesive composition containing the compound A.

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet disclosed herein can be formed by applying (for example, coating) the pressure-sensitive adhesive composition to an appropriate surface and then appropriately performing a curing treatment (drying, cross-linking, etc.). When performing two or more types of curing treatments, these can be performed simultaneously or in multiple stages. The pressure-sensitive adhesive layer having a multi-layer structure of two or more layers can be produced by laminating the pressure-sensitive adhesive layers formed in advance. Alternatively, the pressure-sensitive adhesive composition may be applied onto the first pressure-sensitive adhesive layer formed in advance, and the pressure-sensitive adhesive composition may be cured to form a second pressure-sensitive adhesive layer.

The pressure-sensitive adhesive composition can be applied using a conventional coater such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, or a spray coater. In the pressure-sensitive adhesive sheet having a support, as a method of providing the pressure-sensitive adhesive layer on the support, a direct method of directly applying the pressure-sensitive adhesive composition to the support to form the pressure-sensitive adhesive layer may be used, and peeling may be used. A transfer method may be used in which the pressure-sensitive adhesive layer formed on the surface is transferred to the support.

In the pressure-sensitive adhesive sheet disclosed herein, the thickness of the pressure-sensitive adhesive layer is not particularly limited, and can be appropriately selected depending on the intended purpose. Usually, the thickness of the pressure-sensitive adhesive layer is preferably about 5 to 200 μm, and from the viewpoint of adhesion and the like, 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 further. It is preferably about 80 μm or less, and may be, for example, 60 μm or less. From the viewpoint of facilitating the suppression of the increase in the peeling force due to heating, the thickness of the pressure-sensitive adhesive layer may be, for example, 40 μm or less, 30 μm or less, or 25 μm or less in some embodiments. When the pressure-sensitive adhesive sheet disclosed herein is a double-sided pressure-sensitive adhesive sheet having pressure-sensitive adhesive layers on both sides of a base material, the thickness of each pressure-sensitive adhesive layer may be the same or different.

<Additional adhesive layer>
In some aspects of the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive sheet is configured such that an additional pressure-sensitive adhesive layer is laminated on the back side (opposite side of the pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive surface. There may be. It is preferable that the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive surface and the additional pressure-sensitive adhesive layer are directly in contact with each other and laminated. That is, it is preferable that a separator layer (for example, a resin film such as a polyester film) that completely separates the two pressure-sensitive adhesive layers is not interposed between the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive surface and the additional pressure-sensitive adhesive layer. Additional adhesive layers include, for example, acrylic adhesives, rubber adhesives (natural rubber, synthetic rubber, mixed systems, etc.), silicone adhesives, polyester adhesives, urethane adhesives, poly. The pressure-sensitive adhesive layer may be composed of one or more types of pressure-sensitive adhesives selected from various known pressure-sensitive adhesives such as ether-based pressure-sensitive adhesives, polyamide-based pressure-sensitive adhesives, and fluorine-based pressure-sensitive adhesives. From the viewpoint of transparency, weather resistance, and the like, an acrylic pressure-sensitive adhesive may be preferably adopted as a constituent material of the additional pressure-sensitive adhesive layer in some embodiments. For other matters of the additional pressure-sensitive adhesive layer, the same structure as the pressure-sensitive adhesive layer described above can be adopted, or an appropriate structure is adopted according to the application and purpose based on known or commonly used techniques and common general knowledge. Therefore, detailed description thereof will be omitted here.

<Base material>
In a single-sided adhesive type or double-sided adhesive type pressure-sensitive adhesive sheet with a base material, examples of the base material that supports (backs) the pressure-sensitive adhesive layer include a resin film, paper, cloth, rubber sheet, foam sheet, metal foil, and a composite thereof. Various sheet-like base materials such as a body can be used. The base material may be a single layer, or may be a laminate of the same type or different types of base materials. In addition, in this specification, a single layer means a layer having the same composition, and includes the form in which a plurality of layers having the same composition are laminated.

In a preferred embodiment, a base material having a resin sheet as a main component (resin film base material) can be used. Examples of the resin constituting the base material include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymerized polypropylene, block copolymerized polypropylene, homopolyprolene, and polybutene. , Polymethylpentene, ethylene-vinyl acetate copolymer (EVA), ionomer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester (random, alternating) copolymer, ethylene-butene Polypropylene resins such as polymers, ethylene-hexene copolymers; polyurethane; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate, polybutylene terephthalate (PBT); polycarbonate; polyimide; polyether ether ketone; polyetherimide; aramid , Polypropylene such as total aromatic polyamide; polyphenyl sulfide; fluororesin; polyvinyl chloride; polyvinylidene chloride; cellulose resin; silicone resin; and the like. The above resins may be used alone or in combination of two or more to form all or part of a substrate (eg, any layer in a substrate having a laminated structure of two or more layers).

As required, fillers (inorganic fillers, organic fillers, etc.), antioxidants, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, plasticizers, colorants (pigments, dyes, etc.) are used for the base material. Etc.) and other various additives may be blended.

The base material can be produced by any suitable method. For example, it can be produced by a known method such as a calendar method, a casting method, an inflation extrusion method, or a T-die extrusion method. Further, if necessary, it may be produced by performing a stretching treatment.

For the purpose of improving the adhesion to the pressure-sensitive adhesive layer and the retention of the pressure-sensitive adhesive layer on the surface of the base material on the pressure-sensitive adhesive layer side, for example, corona discharge treatment, plasma treatment, sand mat processing treatment, ozone exposure treatment, etc. Known or commonly used, such as physical treatments such as flame exposure treatment, high piezoelectric impact treatment, ionizing radiation treatment; chemical treatments such as acid treatment, alkali treatment, and chromium acid treatment; easy adhesion treatment with a coating agent (undercoating agent); Surface treatment may be applied. Further, a conductive vapor-deposited layer containing a metal, an alloy, an oxide thereof, or the like may be provided on the surface of the base material for the purpose of imparting antistatic ability.

In some preferred embodiments, an undercoat layer is provided on the pressure-sensitive surface of the substrate. In other words, an undercoat layer may be placed between the substrate and the pressure-sensitive adhesive layer. The undercoat layer forming material is not particularly limited, and is urethane (polyisocyanate) resin, polyester resin, acrylic resin, polyamide resin, melamine resin, olefin resin, polystyrene resin, epoxy resin, and phenol resin. One or more kinds of resins, isocyanurate-based resins, polyvinyl acetate-based resins and the like can be used. When an acrylic-based adhesive layer is provided on the resin film base material via an undercoat layer, a polyester-based, urethane-based, or acrylic-based undercoat layer is preferable. When an acrylic pressure-sensitive adhesive layer is provided on a polyester-based substrate such as a PET film via an undercoat layer, a polyester-based undercoat layer is particularly preferable. The thickness of the undercoat layer is not particularly limited and may generally be in the range of approximately 0.1 μm to 10 μm (eg, 0.1 μm to 3 μm, typically 0.1 μm to 1 μm). The undercoat layer can be formed using a known or conventional coater such as a gravure roll coater or a reverse roll coater.

When the pressure-sensitive adhesive sheet disclosed herein is a single-sided adhesive pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is provided on one side of the base material, a release treatment agent (back surface treatment) is applied to the non-formation surface (back surface) of the pressure-sensitive adhesive layer of the base material. The peeling treatment may be performed by the agent). The back treatment agent that can be used for forming the back treatment layer is not particularly limited, and is intended for silicone-based back treatment agents, fluorine-based back treatment agents, long-chain alkyl-based back treatment agents, and other known or conventional treatment agents. It can be used according to the application.

The thickness of the base material is not particularly limited and can be appropriately selected depending on the intended purpose, but generally it can be about 3 μm to 800 μm. From the viewpoint of processability and handleability of the pressure-sensitive adhesive sheet (for example, workability at the time of sticking or peeling to an adherend), it is appropriate that the thickness of the base material is 5 μm or more, and 10 μm or more. From the viewpoint of enhancing the protection of the adherend, it is preferably 20 μm or more, and may be 30 μm or more, or 40 μm or more. In some embodiments where protection is more important, the thickness of the substrate can be, for example, 55 μm or greater, 75 μm or greater, or 90 μm or greater. Further, from the viewpoint of reducing the load on the adherend at the time of peeling from the adherend, the thickness of the base material is usually preferably 300 μm, preferably 200 μm or less, and is preferably 150 μm. It may be 125 μm or less, 80 μm or less, or 60 μm or less.

The total thickness of the pressure-sensitive adhesive sheet (which may include the pressure-sensitive adhesive layer and the base material but does not include the release liner) disclosed herein is not particularly limited, and is appropriately in the range of approximately 10 μm to 1000 μm. The total thickness of the pressure-sensitive 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 may be in the range of 20 μm to 200 μm in consideration of adhesion and handleability. .. Further, from the viewpoint of enhancing the protection of the adherend, it is advantageous that the total thickness of the adhesive sheet is about 30 μm or more, preferably about 40 μm or more, and about 50 μm or more (for example, 60 μm or more). Is more preferable. In some embodiments where protection is more important, the total thickness of the pressure-sensitive adhesive sheet may be greater than 65 μm, greater than 80 μm, or greater than 100 μm.

<Adhesive sheet>
(Initial normal peeling force Fd ₀ )
The pressure-sensitive adhesive sheet disclosed here preferably has an initial normal peeling force Fd ₀ of 0.10 N / 20 mm or more. As a result, the pressure-sensitive adhesive sheet exhibits appropriate adhesiveness as a pressure-sensitive adhesive sheet for semiconductor processing, and can contribute to the improvement of workability. For example, when the pressure-sensitive adhesive sheet disclosed herein is used as a back-glide tape that protects the circuit forming surface of the semiconductor wafer (adhesive body) in the back-glide process of the semiconductor wafer, the pressure-sensitive adhesive sheet is peeled off during back-glide. It is possible to prevent the semiconductor wafer from being chipped. The upper limit of the initial normal peeling force Fd ₀ is not particularly limited, but from the viewpoint of facilitating the peeling force after heating to be suppressed to a predetermined value or less, it is usually appropriate to be less than 1.00 N / 20 mm, and 0.60 N / It is more preferably 20 mm or less, and may be 0.40 N / 20 mm or less, or 0.30 N / 20 mm or less. The initial normal peeling force Fd ₀ is measured by the method described above, and more specifically by the method described in Examples described later. The initial normal peeling force Fd ₀ is adjusted by selecting the base polymer, selecting the type and amount of the compound A when using compound A, selecting the type and amount of the cross-linking agent when using a cross-linking agent, and the like. be able to.

(Normal peeling force Fd _a )
The PSA sheet disclosed herein is typically release force _Fd a (0.99 ° C. after heating Normal peel force) is preferably not more than 1.00 N / 20 mm. As a result, even if the adhesive sheet is exposed to a high temperature after being attached to the adherend, it is possible to suppress an increase in the load received on the adherend during the subsequent peeling. By performing the peeling from the adherend by the water peeling method, the load on the adherend can be further reduced. In some embodiments, the normal peeling force after heating at 150 ° C. is more preferably 0.60 N / 20 mm or less, more preferably 0.40 N / 20 mm or less, from the viewpoint of reducing the load on the adherend at the time of peeling. Is even more preferable. Normally, the lower limit of the peeling force after heating at 150 ° C. is not particularly limited, but from the viewpoint of balancing the adhesion to the adherend and the joining reliability during processing, for example, it may be 0.005N / 20mm or more, and is 0. It may be 0.01 N / 20 mm or more, or 0.02 N / 20 mm or more. The normal peeling force after heating at 150 ° C. is measured by the method described above, and more specifically by the method described in Examples described later. The normal peeling force after heating at 150 ° C. is adjusted by selecting a base polymer, selecting the type and amount of the compound A when using compound A, selecting the type and amount of the cross-linking agent when using a cross-linking agent, and the like. can do.

Incidentally, even at high pressure-sensitive adhesive sheet from any one of the upper limit usually peel force Fd _a is described above, if possible embodiment sufficient light release by water stripping (e.g., water release force Fw _a is 0. 40N / 20mm or less, more preferably 0.30N / 20mm or less), the adhesive sheet is preferably peeled off after heating by a water peeling method to cause a load on the adherend and generation of adhesive residue. Can be suppressed. Therefore, usually peel force Fd _a pressure-sensitive adhesive sheet in such embodiments may be 1.00 N / 20 mm greater. Normal release force Fd _a pressure-sensitive adhesive sheet in this embodiment is not particularly limited, it may be less for example, 2.00 N / 20 mm or less or 1.00 N / 20 mm.

(Usually peel force _Fd b)
The PSA sheet disclosed herein is typically release force _Fd b (200 ° C. after heating Normal peel force) is preferably not more than 3.00N / 20mm. Thereby, even if it is exposed to a high temperature under more severe conditions, it is possible to suppress an increase in the load on the adherend during the subsequent peeling. By performing the peeling from the adherend by the water peeling method, the load on the adherend at the time of peeling can be further reduced. In some embodiments, the normal peeling force after heating at 200 ° C. is 2.00 N / 20 mm or less, 1.50 N / 20 mm or less, 1.20 N / 20 mm or less, or It is more preferably 1.00 N / 20 mm or less. Normally, the lower limit of the peeling force after heating at 200 ° C. is not particularly limited, but from the viewpoint of balancing the adhesion to the adherend and the joining reliability during processing, for example, it may be 0.01 N / 20 mm or more, and is 0. It may be .02N / 20mm or more, or 0.03N / 20mm or more. The normal peeling force after heating at 200 ° C. is measured by the method described above, and more specifically by the method described in Examples described later. The normal peeling force after heating at 200 ° C. is adjusted by selecting a base polymer, selecting the type and amount of the compound A when using compound A, selecting the type and amount of the cross-linking agent when using a cross-linking agent, and the like. can do.

Incidentally, even at high pressure-sensitive adhesive sheet from any one of the upper limit is usually peel force Fd _b described above, if the aspect that can sufficiently light release by water stripping (e.g., water release force Fw _b is 2. 00N / 20mm or less, preferably 1.00N / 20mm or less), the adhesive sheet preferably suppresses the load on the adherend and the generation of adhesive residue by peeling after heating by the water peeling method. Can be. Therefore, usually peel force Fd _b of the pressure-sensitive adhesive sheet in such embodiments may be 3.00N / 20mm greater. Normal release force Fd _b of the adhesive sheet in this embodiment is not particularly limited, it may be less e.g. 5.00N / 20mm or less, or 4.00N / 20mm.

(Water peeling force Fw _a )
The PSA sheet disclosed herein is preferably water release force _Fw a (0.99 ° C. after heating water peel force) is equal to or less than 0.30 N / 20 mm. As a result, even if the adhesive sheet is exposed to a high temperature after being attached to the adherend, the load on the adherend can be suppressed by performing the subsequent peeling by the water peeling method. In some embodiments, the water peeling force after heating at 150 ° C. is more preferably less than 0.30 N / 20 mm, more preferably 0.25 N / 20 mm or less, from the viewpoint of reducing the load on the adherend at the time of peeling. Is even more preferable. The lower limit of the water peeling force after heating at 150 ° C. is not particularly limited, but from the viewpoint of balancing the adhesion to the adherend and the joining reliability during processing, it may be, for example, 0.01 N / 20 mm or more, and is 0. It may be 0.05 N / 20 mm or more, or 0.01 N / 20 mm or more. The water peeling force after heating at 150 ° C. is measured by the method described above, and more specifically by the method described in Examples described later. The water peeling force after heating at 150 ° C. is adjusted by selecting the base polymer, selecting the type and amount of the compound A when using compound A, selecting the type and amount of the cross-linking agent when using a cross-linking agent, and the like. can do.

(Water peeling force Fw _b )
The pressure-sensitive adhesive sheet disclosed herein preferably has a water peeling force Fw _b (water peeling force after heating at 200 ° C.) of 2.00 N / 20 mm or less. As a result, even if the body is exposed to a high temperature under stricter conditions, the load on the adherend can be suppressed by performing the subsequent peeling by the water peeling method. In some embodiments, the water peeling force after heating at 200 ° C. is 1.50 N / 20 mm or less, 1.00 N / 20 mm or less, 0.80 N / 20 mm or less, or It can be 0.60 N / 20 mm or less. The lower limit of the water peeling force after heating at 200 ° C. is not particularly limited, but from the viewpoint of balancing the adhesion to the adherend and the joining reliability during processing, it may be, for example, 0.05 N / 20 mm or more, and is 0. It may be 0.01 N / 20 mm or more, or 0.03 N / 20 mm or more. The water separation force after heating at 200 ° C. is measured by the method described above, and more specifically by the method described in Examples described later. The water peeling force after heating at 200 ° C. is adjusted by selecting the base polymer, selecting the type and amount of the compound A when using compound A, selecting the type and amount of the cross-linking agent when using a cross-linking agent, and the like. can do.

(Normal peeling force ratio Fd _b / Fd _a )
The PSA sheet disclosed herein is typically release force, defined as the ratio of 0.99 ° C. after heating usually peel strength [N / 20mm] 200 ℃ after heating usually peel force to _{[N / 20mm] (Fd b} / Fd a) The ratio is preferably 4.0 or less. As a result, the adhesive sheet is less susceptible to the peeling force after the high temperature process due to the temperature unevenness that may occur in the high temperature process. Such an adhesive sheet can reduce the risk of adhesive residue when the adhesive sheet that has undergone the high temperature process is peeled off while being attached to the adherend, and the adherend is affected by fluctuations in the peeling force. It is preferable because the load can be reduced. From the viewpoint of further reducing the influence of the temperature unevenness, the peeling force ratio is usually more preferably 3.5 or less, and further preferably 3.0 or less. Usually, the peeling force ratio is typically 1.0 or more.

(Normal peeling force difference Fd _b −Fd _a )
The PSA sheet disclosed herein is generally peeled is defined as the difference between the 0.99 ° C. after heating usually peel strength [N / 20 mm] and 200 ° C. After heating normal peel strength _{[N / 20mm] (Fd b} -Fd a) The force difference is preferably 1.50 N / 20 mm or less. As a result, the adhesive sheet is less susceptible to the peeling force after the high temperature process due to the temperature unevenness that may occur in the high temperature process. Such an adhesive sheet can reduce the risk of adhesive residue when the adhesive sheet that has undergone the high temperature process is peeled off while being attached to the adherend, and the adherend is affected by fluctuations in the peeling force. It is preferable because the load can be reduced. From the viewpoint of further reducing the influence of the temperature unevenness, the difference in peeling force is usually more preferably 1.20 N / 20 mm or less, 1.00 N / 20 mm or less, 0.80 N / 20 mm or less, and 0. It may be .60 N / 20 mm or less. Since the difference in peeling force after heating is usually 0 N / 20 mm or more, the lower limit is not particularly limited, and the closer to 0 N / 20 mm is preferable.

(Initial water peeling force Fw ₀ )
The pressure-sensitive adhesive sheet disclosed herein preferably has an initial water peeling force Fw ₀ of less than 0.10 N / 20 mm. Thereby, the pressure-sensitive adhesive sheet can be suitably lightly peeled by the water peeling method in a mode used for semiconductor processing, for example, which does not involve a high temperature process (for example, a high temperature process of 100 ° C. or higher, preferably 60 ° C. or higher). The load applied to the adherend at the time of peeling can be reduced. Thereby, for example, in the pressure-sensitive adhesive sheet used as a back glide tape, the pressure-sensitive adhesive sheet can be efficiently peeled off from the semiconductor wafer while avoiding damage to the semiconductor wafer thinned by the back grind. In some embodiments, the initial water peeling force Fw ₀ is more preferably less than 0.09 N / 20 mm, not less than 0.07 N / 20 mm, or less than 0.05 N / 20 mm. The lower limit of the initial water peeling force Fw _{0 is not particularly limited, and the smaller the initial water peeling force Fw 0,} the more advantageous it is from the viewpoint of reducing the load on the adherend. On the other hand, from the viewpoint of balancing the adhesion to the adherend and the joining reliability during processing, the initial water peeling force Fw ₀ may be, for example, 0.005N / 20mm or more in some embodiments. It may be 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 peeling force Fw ₀ is measured by the method described above, and more specifically by the method described in Examples described later. The initial water peeling force Fw ₀ is adjusted by selecting the base polymer, selecting the type and amount of the compound A when using compound A, selecting the type and amount of the cross-linking agent when using a cross-linking agent, and the like. be able to.

As the tensile tester used for measuring each of the above-mentioned normal peeling forces and water peeling forces, a precision universal testing machine "Autograph EZ-S" manufactured by Shimadzu Corporation or an equivalent product thereof can be used. In the measurement, if necessary, an appropriate backing material (for example, a PET film having a thickness of about 25 μm) can be attached to the adhesive sheet to be measured to reinforce it.

In the examples described later, the measurement of the normal peeling force and the measurement of the water peeling force were continuously performed for each test piece, but the measurement of the normal peeling force and the measurement of the water peeling force are different test pieces. May be done by. For example, when it is difficult to prepare a test piece having a sufficient length for carrying out continuous measurement, a mode in which measurement is performed using different test pieces can be adopted.

In some preferred embodiments of the PSA sheet disclosed herein, 200 ° C. reduction rate of heating after normal release force _{Fd b [N / 20mm] 200} ℃ after heating water peel force to _Fw b [N / 20mm], for example It can be over 30%. That is, it is preferable that the rate of decrease in water peeling force after heating at 200 ° C. calculated by the following formula is 10% or more.
Water peeling force reduction rate after heating at 200 ° C = 1- (Fw _b / Fd _b )
An adhesive sheet with a high rate of decrease in water peeling power after heating at 200 ° C. can be peeled off by the water peeling method even if the peeling power increases due to heating after sticking, as compared with the case where it is peeled off by the normal peeling method. The force can be significantly reduced, and the load applied to the adherend at the time of peeling can be effectively reduced. In the pressure-sensitive adhesive sheet according to some preferred embodiments, the rate of decrease in water peeling power after heating at 200 ° C. can be 15% or more, 25% or more, or 30% or more. The upper limit of the rate of decrease in water peeling force after heating at 200 ° C. is not particularly limited, but is usually 100% or less, and may be, for example, 95% or less or 90% or less from a practical point of view. ..

<Use>
The pressure-sensitive adhesive sheet disclosed herein can be used for processing various semiconductor wafers. The semiconductor wafer may be, for example, a silicon wafer, a silicon carbide (SiC) wafer, a nitride semiconductor wafer (silicon nitride (SiN), gallium nitride (GaN), etc.), a compound semiconductor wafer such as a gallium hydride wafer, or the like. .. The pressure-sensitive adhesive sheet disclosed herein is attached to the semiconductor wafer, which is typically circuit-formed in the previous step, in the process of manufacturing a semiconductor element (for example, a semiconductor chip) from such a semiconductor wafer. It can be preferably used as a semiconductor processing pressure-sensitive adhesive sheet for protecting and / or fixing the semiconductor wafer during processing of the semiconductor wafer. Examples of processing that can be performed on the semiconductor wafer after the pressure-sensitive adhesive sheets disclosed herein are bonded and before the pressure-sensitive adhesive sheets are peeled off include, but are not limited to, back grind processing and dicing processing. In this specification, even if the shape of the semiconductor wafer to be processed changes due to processing (for example, thinning of the whole or part by back grind processing, individual pieces by dicing processing, etc.), the processed article is continued. Sometimes called a semiconductor wafer.

The bonding of the pressure-sensitive adhesive sheet disclosed herein to a semiconductor wafer can be performed by any suitable method. The temperature at which the adhesive sheets are bonded may be around room temperature (for example, 10 ° C. to 35 ° C.), or may be higher than the room temperature range (for example, over 35 ° C., preferably 60 ° C. to 90 ° C.). .. Laminating the pressure-sensitive adhesive sheets at a temperature higher than the room temperature range can be advantageous from the viewpoint of improving the adhesion of the pressure-sensitive adhesive sheets to the semiconductor wafer. After laminating the adhesive sheet in the room temperature range, the temperature is higher than the room temperature range (for example, 40 ° C. to 90 ° C., preferably 40 ° C. to 60 ° C.) and the pressure is higher than the atmospheric pressure (for example, 1.5 to 10 atm, preferably 3 to 3 to 3 to A heat-pressurizing treatment for imparting 7 atm) may be performed. The time for performing the heat and pressurization treatment is not particularly limited, and can be set so that an appropriate treatment effect can be obtained. In some embodiments, the time for performing the heat-pressurizing treatment can be set to 3 minutes to 1 hour (for example, 5 minutes to 30 minutes) in consideration of the balance between the stability of the treatment effect and the productivity.

The pressure-sensitive adhesive sheet disclosed herein satisfies the above-mentioned condition A and at least one of conditions B to E, so that even if it is exposed to a high temperature during the period from attachment to the adherend to peeling, after that. It can be satisfactorily peeled off from the adherend, and for example, adhesive residue and a load on the adherend can be suppressed. Taking advantage of these features, the pressure-sensitive adhesive sheet disclosed herein can be preferably used in a mode in which a high temperature process is performed after being attached to the adherend and before being peeled off from the adherend. Non-limiting examples of the high temperature process include an ion implantation step into a semiconductor wafer, an ashing step for removing a resist, an annealing step such as laser annealing, and the like. Such a high temperature process can be performed before and / or after the back grind processing, for example, with the adhesive sheet for semiconductor processing (back grind tape) used in the back grind process attached. Therefore, the pressure-sensitive adhesive sheet disclosed herein is subjected to a back grind step and a high temperature before and / or after the back grind step between the step of attaching to the adherend and the step of peeling from the adherend. It can be preferably used as an adhesive sheet for semiconductor processing used in an embodiment including a process.

The pressure-sensitive adhesive sheet disclosed herein may be peeled from the adherend by a normal peeling method (that is, a peeling method that does not use an aqueous stripping liquid such as water), or by a water stripping method. From the viewpoint of improving the peelability, the water peeling method can be preferably adopted in some embodiments. As the aqueous stripping solution used in the water stripping method, water or a mixed solvent containing water as a main component containing a small amount of additives as necessary can be used. As the solvent other than water constituting the mixed solvent, a lower alcohol (for example, ethyl alcohol) or a lower ketone (for example, acetone) that can be uniformly mixed with water can be used. As the additive, a known surfactant, pH adjuster, or the like can be used. From the viewpoint of avoiding contamination of the adherend, in some embodiments, an aqueous stripping solution that is substantially free of additives may be used. From the viewpoint of environmental hygiene, it is particularly preferable to use water as the aqueous stripping solution. The water is not particularly limited, and for example, distilled water, ion-exchanged water, tap water, or the like can be used in consideration of the purity and availability required according to the application.

<Semiconductor device manufacturing method>
An embodiment of a semiconductor device manufacturing method using the pressure-sensitive adhesive sheet disclosed herein will be described below. The semiconductor element manufacturing method of this embodiment includes a step (1) of adhering an adhesive surface of an adhesive sheet for semiconductor processing to the circuit forming surface side of a semiconductor wafer having a circuit forming surface, and the semiconductor to which the adhesive sheet is attached. The wafer includes a step (2) of processing the wafer from the side opposite to the pressure-sensitive adhesive sheet, and a step (3) of peeling the pressure-sensitive adhesive sheet from the processed semiconductor wafer.

The step (3) is preferably performed by supplying an aqueous stripping liquid to the stripping front of the pressure-sensitive adhesive sheet from the processed semiconductor wafer (adhesion). As a result, by lightly peeling the adhesive sheet, it is possible to suppress adhesive residue and reduce the load on the adherend (semiconductor wafer after processing). In some embodiments, the step (3) can be preferably carried out by the pressure-sensitive adhesive sheet peeling method described later.

Preferably, after the step (1) and before the step (3), the high temperature process as described above is performed. After the step (1) and before the step (3), a process involving irradiation with active energy rays (for example, ultraviolet rays) may be performed. The high temperature process and the active energy ray irradiation process may be performed in the step (2), before the step (2), or after the step (2), respectively.

In some embodiments, the step (2) can be a backgrinding step. In this case, the adhesive sheet is used as a back grind tape. The backgrinding process can be performed by any suitable method. The backgrinding step may be a step of thinning the semiconductor wafer to which the adhesive sheet is bonded until the thickness of the semiconductor wafer is, for example, 150 μm or less, 100 μm or less, 50 μm or less, or 30 μm or less. In the aspect of thinning in this way, the effect of peeling the pressure-sensitive adhesive sheet with water in the step (3) can be preferably exhibited. The back grind step may be performed so that the inside of the annular convex portion becomes a concave portion (that is, a TAIKO (registered trademark) wafer can be obtained). In this case, the thickness of the thinned semiconductor wafer means the thickness of the recess. Further, although not particularly limited, the thickness of the semiconductor wafer before backgrinding may be, for example, about 500 μm to 1000 μm.

The semiconductor device manufacturing method disclosed herein may further include any suitable steps. Examples of such an optional step include, but are not limited to, an etching step, a photolithograph step, an ion injection step, a dicing step, a die bonding step, a wire bonding step, a packaging step, and the like. Each of the steps exemplified above may be performed in the step (2), after the step (2), before the step (3), or after the step (3). It may be done.

<Adhesive sheet peeling method>
According to this specification, there is provided a pressure-sensitive adhesive sheet peeling method for peeling a pressure-sensitive adhesive sheet attached to an adherend from the adherend. The method is such that the aqueous stripping liquid follows the movement of the stripping front in a state where the aqueous stripping solution is present at the interface between the adherend and the adhesive sheet in the peeling front of the adhesive sheet from the adherend. It may include a water stripping step of stripping the pressure-sensitive adhesive sheet from the adherend while advancing the liquid's entry into the interface. Here, the peeling front refers to a portion where the adhesive surface of the pressure-sensitive adhesive sheet begins to separate from the adherend when the pressure-sensitive adhesive sheet is peeled off from the adherend. According to the water peeling step, the adhesive sheet can be peeled from the adherend by effectively utilizing the aqueous stripping liquid. The peeling method can be preferably carried out, for example, by peeling any of the pressure-sensitive adhesive sheets disclosed herein from the adherend.

The adherend in the peeling method disclosed herein can be various semiconductor wafers exemplified above. The semiconductor wafer may be a circuit-formed semiconductor wafer. The peeling method disclosed herein can be preferably used as a method for peeling the pressure-sensitive adhesive sheet attached to the circuit-forming surface of the circuit-formed semiconductor wafer from the circuit-forming surface. After the adhesive sheet is attached to the adherend, a high temperature process may be performed before the start of the water peeling.

As the pressure-sensitive adhesive sheet to be peeled off from the adherend by the above-mentioned peeling method, any of the pressure-sensitive adhesive sheets disclosed herein can be preferably used. Therefore, the peeling method is suitable as a peeling method for any of the pressure-sensitive adhesive sheets disclosed herein.

In some embodiments, the peeling method comprises forming an initial peeling front by forcibly lifting the adhesive sheet from the adherend at one end of the outer edge of the adhesive sheet attached to the adherend. The above-mentioned adhesion is carried out while supplying the aqueous release liquid to the peeling front and advancing the invasion of the aqueous peeling liquid into the interface between the adhesive sheet and the adherend following the movement of the peeling front. It can be preferably carried out in a mode including peeling the pressure-sensitive adhesive sheet from the body. The initial peeling front is formed, for example, by inserting the tip of a jig such as a cutter knife or a needle into the interface between the adhesive sheet and the adherend, scratching the adhesive sheet with a hook or a nail, and lifting the adhesive sheet. A strong adhesive tape, a suction cup, or the like is attached to the back surface of the adhesive sheet to lift the edge of the adhesive sheet. By forming the initial peeling front in this way and then supplying the water-based stripping liquid to the peeling front to start water peeling, the water-based stripping liquid can be efficiently supplied to the peeling front. Further, in the peeling method and the pressure-sensitive adhesive sheet used in the peeling method, good water peelability after the operation of forcibly forming the initial peeling front to create a trigger for peeling and such an operation are not performed. It is possible to preferably achieve both high water resistance and reliability in some cases.

In some embodiments, the stripping method supplies a new aqueous stripping solution after supplying the aqueous stripping solution to the initial stripping front (ie, after supplying the aqueous stripping solution at the start of water stripping). It can be preferably carried out in a manner in which the peeling of the pressure-sensitive adhesive sheet is promoted without any trouble. Alternatively, if the aqueous stripping liquid that follows the movement of the stripping front and enters the interface between the adhesive sheet and the adherend is exhausted or insufficient during the progress of water stripping, the water stripping is started. Later, an additional aqueous stripping solution may be supplied intermittently or continuously. For example, when the length of the peeling front increases as the peeling progresses (for example, when water peeling proceeds from one end of the outer edge of the disk-shaped adherend in the radial direction of the circle), or on the surface of the adherend. When the aqueous stripping solution is likely to remain, a mode in which the aqueous stripping solution is additionally supplied after the start of water stripping can be preferably adopted. Further, the position for supplying the aqueous stripping solution may be one place or a plurality of places. When an additional aqueous stripping solution is supplied after the start of water stripping, the number of positions for supplying the aqueous stripping solution may be increased or decreased after the start of water stripping.

The matters disclosed in this specification include the following.
[1] An adhesive sheet for semiconductor processing including an adhesive layer constituting an adhesive surface.
Adhesive sheet for semiconductor processing, where the initial normal peeling force Fd ₀ is 0.10 N / 20 mm or more, and the normal peeling force Fd _a after heat treatment at 150 ° C. for 15 minutes is 1.00 N / 20 mm or less. ..
[2] An adhesive sheet for semiconductor processing including an adhesive layer constituting an adhesive surface.
Water measured by supplying water to the peeling front of the adhesive sheet from the adherend after the initial normal peeling force Fd ₀ is 0.10 N / 20 mm or more and the heat treatment is performed at 150 ° C. for 15 minutes. _{An adhesive sheet for semiconductor processing having a} peeling force Fw a of 0.30 N / 20 mm or less.
[3] An adhesive sheet for semiconductor processing including an adhesive layer constituting an adhesive surface.
Adhesive sheet for semiconductor processing, where the initial normal peeling force Fd ₀ is 0.10 N / 20 mm or more, and the normal peeling force Fd _b after heat treatment at 200 ° C. for 15 minutes is 3.00 N / 20 mm or less. ..
[4] An adhesive sheet for semiconductor processing including an adhesive layer constituting an adhesive surface.
The initial normal peeling force Fd ₀ is 0.10 N / 20 mm or more, and after heat treatment at 200 ° C. for 15 minutes, water is supplied to the peeling front of the adhesive sheet from the adherend to measure the pressure. An adhesive sheet for semiconductor processing having a water peeling force Fw _b of 2.00 N / 20 mm or less.
[5] Normal peel strength after the heat treatment was carried out in 0.99 ° C. for 15 minutes and _{Fd a} [N / 20mm], normal peel strength after the heat treatment for 15 minutes at 200 ℃ _Fd b [N / 20mm ] because the following formula: _Fd b / Fd _a; normal release force ratios calculated by is 4.0 or less, the [1] a semiconductor processing adhesive sheet according to any one of to [4].
[6] 0.99 ° C. at normal peel strength after the heat treatment was carried out for 15 minutes _Fd a and [N / 20mm], normal peel strength after the heat treatment for 15 minutes at 200 ℃ _Fd b [N / 20mm ], The adhesive sheet for semiconductor processing according to any one of the above [1] to [5], wherein the normal peeling force difference calculated by the following formula: Fd _b −Fd _{a; is 1.50 N / 20 mm or less.} ..
[7] The pressure-sensitive adhesive sheet for semiconductor processing according to any one of [1] to [6] above, which comprises a base material that supports the pressure-sensitive adhesive layer.
[8] An adhesive sheet for semiconductor processing including an adhesive layer constituting an adhesive surface, which satisfies the following conditions A and at least one of the following conditions B to E.
(Condition A) The initial normal peeling force Fd ₀ is 0.10 N / 20 mm or more.
(Condition B) 0.99 ° C. under normal release force Fd _a after the heat treatment was carried out for 15 minutes is not more than 1.00 N / 20 mm.
Water release force Fw _a measured by supplying water to the peeling front from the adherend of the adhesive sheet is not more than 0.30 N / 20 mm after the heat treatment (condition C) 0.99 ° C. for 15 minutes ..
Normal release force Fd _b after the heat treatment (condition D) 200 ° C. for 15 minutes is less than 3.00N / 20mm.
(Condition E) After heat treatment at 200 ° C. for 15 minutes, water is supplied to the peeling front of the adhesive sheet from the adherend, and the water peeling force Fw _b measured is 2.00 N / 20 mm or less. is there.
[9] The adhesive sheet according to the above [8], which satisfies at least the above conditions A and C.
[10] The pressure-sensitive adhesive sheet for semiconductor processing according to any one of [1] to [9] above, wherein the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer.
[11] The pressure-sensitive adhesive layer contains at least one compound A selected from the group consisting of a surfactant and a compound having a polyoxyalkylene skeleton as a heat-resistant release agent [1] to [10]. Adhesive sheet for semiconductor processing according to any one of.
[12] The pressure-sensitive adhesive sheet for semiconductor processing according to any one of [1] to [11] above, wherein a cross-linking agent is used for the pressure-sensitive adhesive layer.
[13] The pressure-sensitive adhesive sheet for semiconductor processing according to any one of [1] to [12] above, wherein the cross-linking agent contains an isocyanate-based cross-linking agent.
[14] The pressure-sensitive adhesive sheet for semiconductor processing according to any one of [1] to [12] above, wherein the cross-linking agent contains an isocyanate-based cross-linking agent and an epoxy-based cross-linking agent.
[15] A method for manufacturing a semiconductor element using the adhesive sheet for semiconductor processing according to any one of the above [1] to [14].
The step (1) of adhering the adhesive surface of the adhesive sheet for semiconductor processing to the circuit forming surface side of the semiconductor wafer having the circuit forming surface, and
The step (2) of processing the semiconductor wafer to which the adhesive sheet is attached from the side opposite to the adhesive sheet, and
A method for manufacturing a semiconductor element, which comprises a step (3) of peeling the pressure-sensitive adhesive sheet from the processed semiconductor wafer.
[16] The above [15] includes a high temperature exposure step of performing a high temperature process (for example, a high temperature process of 100 ° C. or higher, preferably 60 ° C. or higher) after the step (1) and before the step (3). The method for manufacturing a semiconductor device according to the description.
[17] The semiconductor device manufacturing method according to the above [15] or [16], wherein the step (3) is performed by a water peeling method.

Hereinafter, some examples of the present invention will be described, but the present invention is not intended to be limited to those shown in such examples. In the following description, "part" and "%" are based on weight unless otherwise specified.

<Evaluation method>
1. 1. Measurement of initial normal peeling force Fd ₀ A test piece is prepared by cutting the adhesive sheet to be measured into a strip having a width of 20 mm. In an environment of 23 ° C. and 50% RH, use a hand roller to apply the adhesive surface of the test piece to the mirror surface of a 6-inch silicon wafer (manufactured by Shin-Etsu Chemical Co., Ltd., 6-inch N <100> -100) as an adherend. Laminate and leave for 30 minutes to prepare a sample for evaluation.
Then, in an environment of 23 ° C. and 50% RH, a cutter knife is inserted into the interface between the test piece of the evaluation sample and the adherend to peel off one end of the test piece in the longitudinal direction from the adherend, and JIS According to Z0237: 2009 "10.4.1 Method 1: 180 ° peeling adhesive strength to test plate", specifically, a tensile tester (precision universal tester "Auto" manufactured by Shimadzu Corporation) at a test temperature of 23 ° C. Graph EZ-S ”) is used to measure the peel strength under the conditions of a tensile speed of 300 mm / min and a peel angle of 180 degrees. The peel strength is measured so that the test piece attached to the adherend is peeled from the bottom to the top. The measurement is performed three times, and the average value thereof is set to the initial normal peeling force Fd ₀ [N / 20 mm].

2. Measurement of initial water peeling force Fw _{0 In} the measurement of the normal peeling force Fd ₀ , 20 μL of distillation is performed at a portion (peeling front) where the test piece begins to separate from the adherend while the test piece is being peeled from the adherend. Water is supplied and the peel strength after the distilled water supply is measured. The measurement is performed for each measurement of each peel strength (that is, three times), and the average value thereof is defined as the initial water peeling force Fw ₀ [N / 20 mm].

3. 3. Measurement of normal peeling force after heating (normal peeling force Fd _a after heating at 150 ° C)
The evaluation sample prepared in the same manner as in the measurement of the initial normal peeling force Fd _{0 is heated at 150 ° C. for 15 minutes.} After heating, allow to cool in a normal temperature (25 ° C.) environment for 30 minutes. After allowing to cool, the peel strength is measured in the same manner as _{the above-mentioned measurement of the initial normal peeling force Fd 0.} The measurement is performed three times, and the average value thereof is set to _a normal peeling force Fda [N / 20 mm] after heating at 150 ° C.
_{(Normal peeling force Fd b} after heating at 200 ° C.)
200 ° C. The heating conditions, in addition to changing the 15 minutes in the same manner as in the measurement of the 0.99 ° C. After heating usually peel force Fd _a, to measure the post-200 ° C. usually heated peel force _Fd b [N / 20mm].

4. Measurement of water peeling force after heating (water peeling force after heating at 150 ° C. Fw _a )
In the above measurement 0.99 ° C. After heating usually peel force Fd _a, the test piece in the middle of peeling from the adherend, to supply distilled water 20μL from the adherend at a location (peeling front) of the test piece begins to leave , The peel strength after supplying the distilled water is measured. The measurement is performed for each measurement of each peel strength (that is, three times), and the average value thereof is set to 150 heat peeling forces Fw _a and Fw _b [N / 20 mm].
_{(Water peeling force Fw b} after heating at 200 ° C)
_{The water peeling force Fw b} [N / 20 mm] after heating at 200 ° C. is measured in the same manner as the measurement of the _{water peeling force Fw a} after heating at 150 ° C. except that the heating conditions are changed to 200 ° C. for 15 minutes.

<Example 1>
(Preparation of adhesive composition)
100 parts of n-butyl acrylate (BA) and 3 parts of acrylic acid as a monomer raw material, 0.2 parts of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and toluene as a polymerization solvent. And were mixed to prepare a monomer composition.
The above monomer composition is put into a 1L round bottom separable flask into an experimental apparatus for polymerization equipped with a separable cover, a separating funnel, a thermometer, a nitrogen introduction tube, a Liebig condenser, a vacuum seal, a stirring rod, and a stirring blade. The mixture was charged and replaced with nitrogen at room temperature for 2 hours with stirring. Then, it was kept at 60 ° C. for 5 hours for polymerization under a nitrogen stream with stirring to obtain a solution of polymer P1 (Mw about 1 million). The Tg calculated from the Fox formula based on the composition of the monomer raw material is −52.3 ° C.

The solution of the polymer P1 is cooled to room temperature, and per 100 parts of the polymer P1 in the solution, an isocyanate-based cross-linking agent (trimethylolpropane / tolylene diisocyanate trimer adduct, manufactured by Toso Co., Ltd., trade name "Coronate L" , Solid content concentration 75% by weight) based on solid content, 2.0 parts, and 0.7 part of epoxy cross-linking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C") is added and mixed to adhere. The agent composition C1 was prepared.

(Preparation and evaluation of adhesive sheet)
The pressure-sensitive adhesive composition C1 is applied to the peeling surface of a 38 μm-thick peeling film (MRF38, manufactured by Mitsubishi Resin Co., Ltd.) in which one side of the polyethylene terephthalate (PET) film is a peeling surface by silicone treatment, and the pressure is 2 at 140 ° C. It was dried for a minute to form a 20 μm thick pressure-sensitive adhesive layer. The adhesive layer is attached to the easy-adhesive surface of an easy-adhesion-treated PET film (thickness 50 μm) as a base material, and then aged at 50 ° C. for 2 days to obtain an adhesive sheet (with a base material) according to this example. Single-sided adhesive sheet) was obtained.
The obtained pressure-sensitive adhesive sheet, the peel strength was measured by the method described above, was calculated normal peel strength ratio from the measured values obtained _(Fd b / Fd _a) and usually peel force difference _(Fd b -Fd _a). The results are shown in Table 1.

<Example 2>
Nonionic surfactant A1 (polyoxyethylene sorbitan monolaurate, which is a compound A that dissolves in the solution of the polymer P1 without phase separation in the above-mentioned test I per 100 parts of the polymer P1 in the solution. A sorbitan fatty acid ester manufactured by Kao Co., Ltd., trade name "Leodor TW-L 120", number of moles of ethylene oxide added 20, 0.1 part of HLB 16.7) was further added. The pressure-sensitive adhesive composition C2 was prepared in the same manner as in the preparation of the pressure-sensitive adhesive composition C1 except for the above points.
The nonionic surfactant A1 was used in the form of an ethyl acetate solution so that the above amount was added based on the solid content. The same applies to the preparation of the pressure-sensitive adhesive compositions C3 to C5.
A pressure-sensitive adhesive sheet according to this example was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive composition C2 was used.
The obtained adhesive sheet was evaluated in the same manner as in Example 1. The results are shown in Table 1.

<Examples 3 to 5>
Similar to the preparation of the pressure-sensitive adhesive composition C2, except that the amount of the nonionic surfactant A1 added to 100 parts of the polymer P1 was changed as shown in Table 1, the pressure-sensitive adhesive compositions C3 to Examples 3 to 5 C5 was prepared. The pressure-sensitive adhesive sheets according to Examples 3 to 5 were obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive compositions C3 to C5 were used. The obtained adhesive sheet was evaluated in the same manner as in Example 1. The results are shown in Table 1.

As shown in Table 1, the pressure-sensitive adhesive sheets of Examples 2 to 5 have a clearly lower peeling force after high-temperature exposure than the pressure-sensitive adhesive sheets of Example 1, and have adhesion to an adherend and joint reliability during processing. It was excellent in balance with. Examples 3 to 5 were particularly favorable results.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples illustrated above.

1,2,3,4,5,6 Adhesive sheet 10 Base material 10A First surface 10B Second surface 21,22 Adhesive layer 21A First adhesive surface 21B Second adhesive surface 31,32 Peeling liner

Claims (7)

An adhesive sheet for semiconductor processing including an adhesive layer constituting an adhesive surface.
Adhesive sheet for semiconductor processing, where the initial normal peeling force Fd ₀ is 0.10 N / 20 mm or more, and the normal peeling force Fd _a after heat treatment at 150 ° C. for 15 minutes is 1.00 N / 20 mm or less. .. An adhesive sheet for semiconductor processing including an adhesive layer constituting an adhesive surface.
Water measured by supplying water to the peeling front of the adhesive sheet from the adherend after the initial normal peeling force Fd ₀ is 0.10 N / 20 mm or more and the heat treatment is performed at 150 ° C. for 15 minutes. _{An adhesive sheet for semiconductor processing having a} peeling force Fw a of 0.30 N / 20 mm or less. An adhesive sheet for semiconductor processing including an adhesive layer constituting an adhesive surface.
Adhesive sheet for semiconductor processing, where the initial normal peeling force Fd ₀ is 0.10 N / 20 mm or more, and the normal peeling force Fd _b after heat treatment at 200 ° C. for 15 minutes is 3.00 N / 20 mm or less. .. An adhesive sheet for semiconductor processing including an adhesive layer constituting an adhesive surface.
The initial normal peeling force Fd ₀ is 0.10 N / 20 mm or more, and after heat treatment at 200 ° C. for 15 minutes, water is supplied to the peeling front of the adhesive sheet from the adherend to measure the pressure. An adhesive sheet for semiconductor processing having a water peeling force Fw _b of 2.00 N / 20 mm or less. Normal peel strength after the heat treatment for 15 minutes at 0.99 ° C. and _{Fd a} [N / 20mm], since the normal peel strength after the heat treatment for 15 minutes at _{200 ℃ Fd b [N / 20mm} ] The pressure-sensitive adhesive sheet for semiconductor processing according to any one of claims 1 to 4, wherein the normal peeling force ratio calculated by the following formula: Fd _b / Fd _{a; is 4.0 or less.} Normal peel strength after the heat treatment for 15 minutes at 0.99 ° C. and _{Fd a} [N / 20mm], since the normal peel strength after the heat treatment for 15 minutes at _{200 ℃ Fd b [N / 20mm} ] The pressure-sensitive adhesive sheet for semiconductor processing according to any one of claims 1 to 5, wherein the normal peeling force difference calculated by the following formula: Fd _b −Fd _{a; is 1.50 N / 20 mm or less.} The pressure-sensitive adhesive sheet for semiconductor processing according to any one of claims 1 to 6, which includes a base material that supports the pressure-sensitive adhesive layer.

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