Adhesive sheets for semiconductor device processing

Abstract

To provide a pressure-sensitive adhesive sheet for semiconductor element processing which protects a semiconductor element from electrostatic breakdown caused by peel charging and friction charging even in a case where the semiconductor element is under a high-humidity environment and / or in a case where a high voltage is applied.SOLUTION: A pressure-sensitive adhesive sheet 100 for semiconductor element processing includes a pressure-sensitive adhesive agent layer 20 and a substrate 10. Surface resistivity ρsBM of the substrate and surface resistivity ρsPA of the pressure-sensitive adhesive agent layer are equal to or less than 1.0×1013 Ω / square. Surface resistivity ρs10VBM of the substrate in a case where 10 V is applied, surface resistivity ρs10VPA of the pressure-sensitive adhesive agent layer in a case where 10 V is applied and surface resistivity ρs1000VBM of the substrate in a case where 1,000 V is applied satisfy formula (1) ρs1000VBM / ρs10VBM≤1000 and formula (2) ρs1000VPA / ρs10VPA≤1000.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an adhesive sheet for processing semiconductor elements. [Background technology]

[0002] Semiconductor elements are manufactured by subjecting silicon wafers to a back grinding process and a dicing process. In these processes, adhesive sheets for semiconductor element processing are used to support and protect the silicon wafer. In the manufacturing process of semiconductor elements, the silicon wafer and the adhesive sheet may become charged due to various factors. For example, peeling electrification when peeling the adhesive sheet from the chuck table after the dicing process, peeling electrification when picking up the semiconductor element, and frictional electrification due to scratching to recover the wafer from the adhesive sheet, etc. These peeling electrification and frictional electrification may cause electrostatic destruction of the semiconductor element, resulting in a decrease in yield.

[0003] It is known that antistatic properties are imparted to adhesive sheets used in semiconductor processing steps by using antistatic agents (for example, Patent Document 1 and Patent Document 2). The voltages generated by peeling electrification and frictional electrification are several hundred volts or more, which may not only electrostatically damage semiconductor elements but also reduce the antistatic properties of the adhesive sheet. In addition, the antistatic properties may decrease during transportation and storage of the adhesive sheet. In particular, the decrease in antistatic properties may be significant under high temperature and high humidity conditions such as in tropical regions. Therefore, appropriate antistatic properties may not be exhibited in situations where antistatic properties are required. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-174201 A [Patent Document 2] International Publication No. 2018 / 003893 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made to solve the above-mentioned conventional problems, and its object is to provide an adhesive sheet for processing semiconductor elements that can protect semiconductor elements from electrostatic destruction caused by peeling electrification and frictional electrification, even when placed in a high humidity environment and / or when a high voltage is applied. [Means for solving the problem]

[0006] The semiconductor processing adhesive sheet according to an embodiment of the present invention includes a substrate and an adhesive layer, and the substrate has a surface resistivity ρs BM and the surface resistivity ρs of the pressure-sensitive adhesive layer PA is 1.0×10 13 Ω / □ or less, and the surface resistivity ρs of the substrate when 10 V is applied 10VBM and the surface resistivity ρs of the adhesive layer when 10 V is applied 10VPA and the surface resistivity ρs of the substrate when 1000 V is applied 1000VBM and the surface resistivity ρs of the adhesive layer when 1000 V is applied 1000VPA and an adhesive sheet for semiconductor element processing, which satisfies the following formula (1) and formula (2): ρs 1000VBM / ρs 10VBM <=1000 (1) ρs 1000VPA / ρs 10VPA <=1000 (2) The adhesive sheet for semiconductor processing according to another embodiment of the present invention includes a substrate and an adhesive layer, and the substrate has a surface resistivity ρs BM and the surface resistivity ρs of the pressure-sensitive adhesive layer PA is 1.0×10 13 Ω / □ or less, and the surface resistivity ρs of the substrate at a humidity of 92% 92%BM and the surface resistivity ρs of the adhesive layer at a humidity of 92% 92%PA satisfies the following equations (3) and (4). ρs 92%BM / ρs BM <=1000 (3) ρs 92%PA / ρs PA <=1000 (4) In one embodiment, the pressure-sensitive adhesive layer contains an ionic liquid. In one embodiment, the content of the ionic liquid in the composition forming the pressure-sensitive adhesive layer is 0.1% by weight to 50% by weight. In one embodiment, the substrate has an antistatic layer on at least one surface, the antistatic layer comprising a quaternary ammonium salt. In one embodiment, the content of the quaternary ammonium salt in the composition for forming the antistatic layer is 0.1% by weight to 50% by weight. Effect of the Invention

[0007] According to the adhesive sheet for semiconductor element processing of the embodiment of the present invention, even when placed in a high humidity environment and / or when a high voltage is applied, the semiconductor element can be protected from electrostatic damage caused by peeling electrification and frictional electrification. The adhesive sheet for semiconductor element processing of the embodiment of the present invention can prevent the deterioration of antistatic performance even when placed in a high humidity condition and when a high voltage is applied. Therefore, by using the adhesive sheet for semiconductor element processing of the embodiment of the present invention, semiconductor elements can be manufactured with a high yield. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view of an adhesive sheet for processing semiconductor elements according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A. Overall composition of adhesive sheet for semiconductor element processing FIG. 1 is a schematic cross-sectional view of a semiconductor element processing adhesive sheet (hereinafter, also referred to as processing adhesive sheet) according to an embodiment of the present invention. The semiconductor element processing adhesive sheet 100 has a substrate 10 and an adhesive layer 20 arranged on one side of the substrate. In one embodiment, the substrate 10 has an antistatic layer (not shown) on at least one side. The antistatic layer may be provided on the surface of the substrate 10 facing the adhesive layer 20, or on the surface of the substrate 10 not in contact with the adhesive layer 20, or on both sides. Preferably, the antistatic layer is formed at least on the surface of the substrate 10 not in contact with the adhesive layer 20. The semiconductor element processing adhesive sheet according to the embodiment of the present invention may include any other appropriate layer (not shown). For example, any appropriate layer may be formed between the substrate and the adhesive layer. The semiconductor element processing adhesive sheet may have a separator provided on the outside of the adhesive layer for the purpose of protecting the adhesive layer until it is used.

[0010] The adhesive sheet for processing semiconductor elements according to the embodiment of the present invention has a surface resistivity ρs of the substrate. BM and the surface resistivity ρs of the adhesive layer PA is 1.0×10 13 Ω / □ or less. ρs BM and ρ PA is 1.0×10 13 By having a surface resistivity ρs of Ω / □ or less, the semiconductor element can be protected from electrostatic damage due to peeling electrification and friction electrification. BM and ρ PA refers to the surface resistivity measured in accordance with JIS K 6911.

[0011] In one embodiment, the adhesive sheet for processing semiconductor elements according to the embodiment of the present invention has a surface resistivity ρs 10VBM and the surface resistivity ρs of the adhesive layer when 10 V is applied 10VPA and the surface resistivity ρs of the substrate when 1000V is applied 1000VBM and the surface resistivity ρs of the adhesive layer when 1000 V is applied 1000VPA and satisfy the following formula (1) and formula (2). 10VBM , ρs 10VPA , ρs1000VBM and ρ 1000VPA By satisfying formula (1) and formula (2), the semiconductor element can be appropriately protected from peeling electrification and frictional electrification even when a high voltage is applied. ρs 1000VBM / ρs 10VBM <=1000 (1) ρs 1000VPA / ρs 10VPA <=1000 (2) ρs 1000VBM / ρs 10VBM and ρ 1000VPA / ρs 10VPA is preferably 100 or less, more preferably 10 or less, and even more preferably 1 or less, that is, the surface resistivity can be maintained even when a high voltage is applied. In this specification, the surface resistivity ρs when 10 V is applied 10VBM and ρ 10VPA The surface resistivity ρs is measured according to JIS K 6911 after placing the adhesive sheet for semiconductor device processing under the condition of an applied voltage of 10V for 1 minute. Also, the surface resistivity ρs when 1000V is applied 1000VBM and ρ 1000VPA refers to the surface resistivity measured in accordance with JIS K 6911 after subjecting the adhesive sheet for semiconductor element processing to an applied voltage of 1000V for 1 minute.

[0012] In one embodiment, the adhesive sheet for processing semiconductor elements according to the embodiment of the present invention has a surface resistivity ρs of 92% humidity of the substrate. 92%BM and the surface resistivity ρs of the adhesive layer at 92% humidity 92%PA satisfies the following formula (3) and formula (4). 92%BM and ρ 92%PA By satisfying formulas (3) and (4), the semiconductor element can be appropriately protected from peel-off electrification and frictional electrification even when placed under high-humidity conditions. ρs 92%BM / ρs BM <=1000 (3) ρs 92%PA / ρs PA <=1000 (4) ρs 92%BM / ρs BMand ρ 92%PA / ρs PA is preferably 100 or less, more preferably 10 or less, and even more preferably 1 or less, that is, the surface resistivity can be maintained even after being placed in a high humidity environment (for example, a humidity of 92%). In this specification, the surface resistivity ρs at a humidity of 92% 92%BM and ρ 92%PA refers to the surface resistivity measured in accordance with JIS K 6911 after leaving the adhesive sheet for semiconductor element processing at rest for 3 days under conditions of 40°C and 92% RH.

[0013] The thickness of the adhesive sheet for processing semiconductor elements according to the embodiment of the present invention can be set to any appropriate thickness. The thickness of the adhesive sheet for processing semiconductor elements is, for example, 15 μm to 500 μm, more preferably 50 μm to 400 μm, and even more preferably 80 μm to 200 μm. By having the thickness within the above range, the semiconductor elements can be appropriately supported and the handleability can be maintained. In addition, the transportation in the device can be efficiently performed, and a decrease in yield can be prevented.

[0014] B. Base material Any appropriate substrate can be used as the substrate 10. The substrate can be one layer or two or more layers. When the substrate is two or more layers, the substrate is used so that the total thickness of the substrate becomes the thickness of the substrate described later.

[0015] The thickness of the substrate is preferably 10 μm to 500 μm, more preferably 30 μm to 300 μm, and further preferably 50 μm to 300 μm. When the substrate has a thickness within the above range, the semiconductor element can be appropriately supported and the occurrence of warping and / or bending can be prevented.

[0016] Surface resistivity of the substrate ρs BM is preferably 1.0×10 5 Ω / □~1.0×10 13 Ω / □, and more preferably 1.0×10 7 Ω / □~1.0×10 12 Ω / □. Surface resistivity of the substrate ρs BMBy ensuring that the thickness is within the above range, the semiconductor element can be appropriately protected from peel-off electrification and frictional electrification even when a high voltage is applied from the outside.

[0017] The substrate may be made of any suitable resin. Specific examples of the resin constituting the substrate include polyester resins such as polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polybutylene naphthalate (PBN), polyolefin resins such as ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, polyethylene, polypropylene, and ethylene-propylene copolymer, polyvinyl alcohol, polyvinylidene chloride, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyamide, polyimide, cellulose, fluorine resin, polyether, and polystyrene resins such as polystyrene, polycarbonate, polyethersulfone, and polyetheretherketone. Preferably, polyolefin resins such as ethylene-vinyl acetate copolymer, polyethylene, polypropylene, and ethylene-propylene copolymer are used.

[0018] The substrate may further contain other components within a range that does not impair the effects of the present invention. Examples of other components include antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, etc. The types and amounts of other components can be any appropriate amount depending on the purpose.

[0019] Preferably, the adhesive sheet for semiconductor element processing according to the embodiment of the present invention has an antistatic layer on at least one surface. By having the substrate have an antistatic layer, it is possible to more easily obtain an adhesive sheet for semiconductor element processing that satisfies the above formulas (1) and (2) or formulas (3) and (4). More preferably, the adhesive sheet for semiconductor element processing according to the embodiment of the present invention has an antistatic layer at least on the surface of the substrate that is not in contact with the adhesive layer. By having an antistatic layer on the surface that is not in contact with the adhesive layer, the semiconductor element can be protected even when a high voltage is applied from the outside.

[0020] The antistatic layer preferably contains a quaternary ammonium salt. The quaternary ammonium salt can function as an antistatic agent. By containing a quaternary ammonium salt in the antistatic layer, the semiconductor element can be protected from electrostatic breakdown due to peeling electrification and frictional electrification even when placed in a high humidity environment and / or when a high voltage is applied. The quaternary ammonium salt may be used alone or in combination of two or more kinds.

[0021] Any suitable quaternary ammonium salt can be used as the quaternary ammonium salt. Examples include quaternary ammonium salts such as tetraethylammonium, tetramethylammonium, tetrapropylammonium, N,N,N-triethyl-N-(2-hydroxyethyl)ammonium, N,N-diethyl-N,N-di(2-hydroxyethyl)ammonium, and quaternary ammonium hydroxide salts such as 2-hydroxyethyltrimethylammonium hydroxide (choline). Preferably, 2-hydroxyethyltrimethylammonium hydroxide can be used. By using these, the semiconductor element can be further protected from electrostatic destruction due to peeling electrification and frictional electrification even when placed in a high humidity environment and / or when a high voltage is applied.

[0022] The antistatic layer can be formed by any suitable method. For example, the antistatic layer can be formed by applying a composition (antistatic layer-forming composition) for forming the antistatic layer containing the above-mentioned quaternary ammonium salt to a substrate and drying it. Any suitable solvent can be used as the solvent used in the antistatic layer-forming composition. For example, organic solvents such as water, alcohols such as methanol, ethanol, isopropyl alcohol, and ketones such as acetone, methyl ethyl ketone, ethyl acetate, toluene, and xylene can be used.

[0023] In the antistatic layer-forming composition, the quaternary ammonium salt is used to reduce the surface resistivity ρs of the substrate. BM is 1.0×10 13It is used in any appropriate amount so that the resistivity is Ω / □ or less. The content of the quaternary ammonium salt in the antistatic layer-forming composition is, for example, 0.01% by weight to 50% by weight, preferably 0.1% by weight to 30% by weight, and more preferably 1% by weight to 10% by weight. When the content ratio of the quaternary ammonium salt is within the above range, the semiconductor element can be further protected from electrostatic breakdown due to peeling electrification and frictional electrification even when placed in a high humidity environment and / or when a high voltage is applied.

[0024] The thickness of the antistatic layer can be set to any appropriate thickness. For example, it is 50 nm to 5000 nm, preferably 70 nm to 1000 nm, and more preferably 80 nm to 200 nm. By setting the thickness of the antistatic layer within the above range, the semiconductor element can be protected from electrostatic breakdown due to peeling electrification and frictional electrification even when placed in a high humidity environment and / or when a high voltage is applied.

[0025] C. Adhesive layer The adhesive layer 20 is formed using a composition containing any suitable adhesive (hereinafter, also referred to as an adhesive layer-forming composition). Preferably, the adhesive layer 20 contains an ionic liquid. The ionic liquid can function as an antistatic agent. By including an ionic liquid, the semiconductor element can be protected from electrostatic breakdown due to peeling electrification and frictional electrification even when placed in a high humidity environment and / or when a high voltage is applied.

[0026] Surface resistivity of adhesive layer ρs PA is preferably 1.0×10 5 Ω / □~1.0×10 13 Ω / □, and more preferably 1.0×10 8 Ω / □~1.0×10 12 Even when a semiconductor element and the adhesive sheet for processing a semiconductor element are subjected to a process in which a high voltage is applied, the semiconductor element can be appropriately protected from peeling electrification and frictional electrification.

[0027] The thickness of the pressure-sensitive adhesive layer can be set to any appropriate value. The thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 100 μm, more preferably 1 μm to 20 μm, and even more preferably 1 μm to 10 μm. When the thickness of the pressure-sensitive adhesive layer is within the above range, the pressure-sensitive adhesive layer can exert sufficient adhesive strength to the adherend.

[0028] C-1. Pressure-sensitive adhesive composition As the adhesive layer-forming composition (adhesive), any appropriate adhesive can be used, such as an acrylic adhesive, a rubber adhesive, a silicon adhesive, or a polyvinyl ether adhesive.

[0029] In one embodiment, the adhesive layer-forming composition is preferably an active energy ray curable adhesive composition.By using an active energy ray curable adhesive, for example, the adhesive strength is reduced by irradiation with active energy rays (typically ultraviolet rays) after dicing, so that the pick-up of the small pieces of work (for example, semiconductor chips) becomes easy, and the peeling electrification during pick-up can be suppressed.

[0030] C-1-1. Base polymer The pressure-sensitive adhesive composition may contain a base polymer exhibiting pressure-sensitive adhesive properties. Examples of monomers constituting the base polymer include hydrophilic monomers. As the hydrophilic monomer, any appropriate monomer having a polar group may be used. Specifically, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; acid anhydride monomers such as maleic anhydride and itanoic anhydride; hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl methacrylate; styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, (meth) Sulfonic acid group-containing monomers such as acryloyloxynaphthalenesulfonic acid; phosphate group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; (N-substituted) amide monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane(meth)acrylamide, and acryloylmorpholine; (meth)acrylic acid aminoalkyl monomers such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate; (meth)acrylic acid alkoxyalkyl monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide;Itaconimide monomers such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, and N-laurylitaconimide; succinimide monomers such as N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, and N-(meth)acryloyl-8-oxyoctamethylenesuccinimide; acetic acid Vinyl monomers such as vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinyl carboxylic acid amides, styrene, α-methylstyrene, and N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; and epoxies such as glycidyl (meth)acrylate. Group-containing acrylic monomers; glycol-based acrylic ester monomers such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; acrylic ester monomers having heterocycles, halogen atoms, silicon atoms, and the like, such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, and silicon (meth)acrylate; and polyfunctional monomers such as hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate. Hydrophilic monomers can be suitably used as hydroxyl group-containing monomers and / or (N-substituted) amide monomers. The hydrophilic monomer may be used alone or in combination of two or more kinds.

[0031] Furthermore, a combination of a hydrophilic monomer and a hydrophobic monomer may be used. As the hydrophobic monomer, any appropriate monomer may be used as long as it has hydrophobicity. Specific examples thereof include vinyl alkyl or aryl ethers having an alkyl group having 9 to 30 carbon atoms, such as vinyl 2-ethylhexanoate, vinyl laurate, vinyl stearate, and stearyl vinyl ether; hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl acrylate, isononyl acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, benzyl (meth)acrylate, lauryl (meth)acrylate, oleyl (meth)acrylate, palmityl (meth)acrylate, and stearyl (meth)acrylate; unsaturated vinyl esters of (meth)acrylic acid derived from fatty acids and aliphatic alcohols; monomers derived from cholesterol; and olefin monomers such as 1-butene, 2-butene, 1-pentene, 1-hexene, 1-octene, isobutylene, and isoprene. The hydrophobic monomer may be used alone or in combination of two or more kinds. The hydrophobic monomer used in the present invention refers to a monomer having a solubility of 0.02 g or less in 100 g of water.

[0032] The base polymer may further contain a monomer component other than the hydrophilic monomer and the hydrophobic monomer. Examples of the other monomer components include alkyl acrylates such as butyl acrylate and ethyl acrylate. The other monomer components may be used alone or in combination of two or more.

[0033] The base polymer may further contain a structural unit derived from an isocyanate-based compound having a curable functional group in the molecule. The base polymer containing a structural unit derived from an isocyanate-based compound can be obtained, for example, by reacting a substituent (e.g., OH group) of the structural unit derived from the hydrophilic monomer with an NCO group of an isocyanate-based compound. Examples of the isocyanate-based compound include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-acryloyloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate, and the like.

[0034] The weight average molecular weight of the base polymer constituting the pressure-sensitive adhesive is preferably 300,000 to 2,000,000, and more preferably 500,000 to 1,500,000. The weight average molecular weight can be measured by GPC (solvent: THF).

[0035] C-1-2. Active energy ray reactive oligomers and thermosetting oligomers The pressure-sensitive adhesive composition preferably further contains an active energy ray reactive oligomer and / or a thermosetting oligomer, more preferably contains an active energy ray reactive oligomer. The active energy ray reactive oligomer and the thermosetting oligomer may be used alone or in combination of two or more kinds.

[0036] Examples of the active energy ray reactive oligomer include urethane acrylate oligomers, epoxy (meth)acrylate oligomers, acrylic (meth)acrylate oligomers, etc. Preferably, urethane acrylate oligomers, acrylic (meth)acrylate oligomers, etc. are used.

[0037] The active energy ray reactive oligomer may be a commercially available product, such as Shikoh (registered trademark) UV-3000B (weight average molecular weight: 18,000) manufactured by Nippon Synthetic Chemical Industry Co., Ltd., or Aronix M321 (weight average molecular weight: 10,000) manufactured by Toagosei Co., Ltd.

[0038] As the thermosetting oligomer, any suitable oligomer having at least one thermosetting functional group such as a glycidyl group, a carboxyl group, a hydroxyl group, or an amino group can be used.

[0039] The active energy ray reactive oligomer and the thermosetting oligomer preferably have a weight average molecular weight of 5000 or more, more preferably 7000 or more, even more preferably 8000 or more, and particularly preferably 10000 or more. The active energy ray reactive oligomer and the thermosetting oligomer preferably have a weight average molecular weight of 70000 or less, and even more preferably 50000 or less. The active energy ray reactive oligomer and the thermosetting oligomer weight average molecular weight can be measured, for example, by GPC (solvent: THF).

[0040] C-1-3. Polymerization initiator The pressure-sensitive adhesive layer-forming composition typically contains a polymerization initiator. As the polymerization initiator, any appropriate initiator can be used, and preferably a photopolymerization initiator is used. As the photopolymerization initiator, any appropriate initiator can be used. As the photopolymerization initiator, for example, α-ketol-based compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and 1-hydroxycyclohexylphenylketone; acetophenone-based compounds such as methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, and 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin ether-based compounds such as benzoin ethyl ether, benzoin isopropyl ether, and anisoin methyl ether; and ketal-based compounds such as benzyl dimethyl ketal. ; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; benzophenone compounds such as benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone; camphorquinone; halogenated ketones; acylphosphinoxides; acylphosphonates, etc. The photopolymerization initiator may be used alone or in combination of two or more. The amount of the photopolymerization initiator used may be set to any appropriate amount. The amount of the photopolymerization initiator used is preferably 1 to 10 parts by weight, and more preferably 3 to 7 parts by weight, based on 100 parts by weight of the base polymer.

[0041] The photopolymerization initiator may be a commercially available product, such as "Irgacure 651", "Irgacure 184", "Irgacure 369", "Irgacure 819", or "Irgacure 2959" manufactured by BASF, or "Omnirad 2959" manufactured by IGM RESINS BV.

[0042] C-1-4. Crosslinking agent The pressure-sensitive adhesive layer-forming composition preferably further contains a crosslinking agent, such as an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a melamine-based crosslinking agent, a peroxide-based crosslinking agent, a urea-based crosslinking agent, a metal alkoxide-based crosslinking agent, a metal chelate-based crosslinking agent, a metal salt-based crosslinking agent, a carbodiimide-based crosslinking agent, or an amine-based crosslinking agent.

[0043] In one embodiment, an isocyanate-based crosslinking agent is preferably used. The isocyanate-based crosslinking agent is preferred because it can react with various functional groups. Specific examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate; and isocyanate adducts such as trimethylolpropane / tolylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, product name "Coronate L"), trimethylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate HL"), and isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate HX"). Preferably, a crosslinking agent having three or more isocyanate groups is used.

[0044] The active energy ray-curable pressure-sensitive adhesive composition may further contain any suitable additive, such as an active energy ray polymerization accelerator, a radical scavenger, a tackifier, a plasticizer (e.g., a trimellitic acid ester-based plasticizer, a pyromellitic acid ester-based plasticizer), a pigment, a dye, a filler, an antiaging agent, a conductive material, an antistatic agent, an ultraviolet absorbing agent, a light stabilizer, a release regulator, a softener, a surfactant, a flame retardant, an antioxidant, etc.

[0045] The content of the crosslinking agent can be any appropriate amount. For example, it is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 8 parts by weight, relative to 100 parts by weight of the base polymer. If it is within such a range, a pressure-sensitive adhesive layer with an appropriately adjusted elastic modulus can be formed.

[0046] C-2. Ionic Liquids Any appropriate ionic liquid can be used as the ionic liquid. An ionic liquid is a salt composed of a cation and an anion, and is liquid at 25° C. Only one type of ionic liquid may be used, or two or more types may be used in combination.

[0047] The cation of the ionic liquid is preferably a non-metallic ion, such as an imidazolium cation, a pyridinium cation, a pyrrolidium cation, a quaternary ammonium cation, and a quaternary phosphonium cation. Preferably, an imidazolium cation can be used. By using these, a semiconductor element can be protected from electrostatic destruction due to peeling electrification and frictional electrification even when placed in a high humidity environment and / or when a high voltage is applied.

[0048] The anion of the ionic liquid is, for example, an anion represented by the following general formula (A), CF3CO2 - , CF3(CF2)3SO3 - , CF3SO3 - , (CF3SO2)3C - , CF3(CF2)2CO2 - , BF3(CF3) -, BF3(C2F5) - , BF3(C3F7) - , BF2(CF3)2 - , BF2(CF3)(C2F5) - , PF5(CF3) - , PF5(C2F5) - , PF5(C3F7) - , PF4(CF3)2 - , PF4(CF3)(C2F5) - , PF3(CF3)3 - , B(C2O4)2 - , CH3CH2OSO3 - , CH3CO2 - etc. [ka] (In formula (A), R 1 and R 2 is a fluorine atom or a perfluoroalkyl group having 1 to 8 carbon atoms, and R 1 and R 2 may be the same or different)

[0049] Above R 1 and R 2 Each of R is preferably a fluorine atom. 1 and R 2 Since each of the groups is a fluorine atom, the semiconductor element can be protected from electrostatic destruction due to peeling electrification and frictional electrification even when placed in a high humidity environment and / or when a high voltage is applied.

[0050] In the pressure-sensitive adhesive layer-forming composition, the ionic liquid is PA is 1.0×10 13The ionic liquid is used in any appropriate amount so that the resistivity is Ω / □ or less. The content of the ionic liquid in the adhesion prevention layer-forming composition is, for example, 0.1% by weight to 50% by weight, preferably 0.5% by weight to 30% by weight, and more preferably 1% by weight to 10% by weight. When the content of the ionic liquid is within the above range, the semiconductor element can be further protected from electrostatic breakdown due to peel electrification and friction electrification even when placed in a high humidity environment and / or when a high voltage is applied.

[0051] C-3.Additives The pressure-sensitive adhesive layer-forming composition may contain any suitable additives, such as crosslinkers, light release agents, catalysts (e.g., platinum catalysts, zirconium catalysts), tackifiers, plasticizers, pigments, dyes, fillers, antioxidants, UV absorbers, light stabilizers, release regulators, softeners, flame retardants, solvents, and the like.

[0052] D. Manufacturing method of adhesive sheet for semiconductor element processing The adhesive sheet for semiconductor element processing can be produced by any suitable method. For example, it can be obtained by a method of applying an adhesive solution (adhesive layer forming composition) to a separator, drying the adhesive layer on the separator, and then laminating the adhesive layer on a substrate. Alternatively, the adhesive layer forming composition can be applied to a substrate and dried to obtain an adhesive sheet for semiconductor element processing. As a method for applying the adhesive layer forming composition, various methods such as bar coater application, air knife application, gravure application, gravure reverse application, reverse roll application, lip application, die application, dip application, offset printing, flexographic printing, and screen printing can be adopted. As a drying method, any suitable method can be adopted.

[0053] E. Applications of adhesive sheets for semiconductor element processing The adhesive sheet for semiconductor element processing can be suitably used in the processing of semiconductor elements. In one embodiment, the adhesive sheet for semiconductor element processing of the embodiment of the present invention can be suitably used as a dicing tape. As described above, the adhesive sheet for semiconductor element processing of the embodiment of the present invention can adequately protect the semiconductor element even when a high voltage is applied from the outside. For example, after the dicing process, the adhesive sheet for semiconductor element processing is peeled off from the chuck table. When peeled off, a high voltage (e.g., 8000V) may be applied to the adhesive sheet for semiconductor element processing. The adhesive sheet for semiconductor element processing of the embodiment of the present invention can maintain antistatic performance even when a high voltage is applied. As a result, electrostatic destruction of the element due to peeling electrification and frictional electrification occurring in the subsequent pick-up process or the like can be prevented. EXAMPLES

[0054] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the examples, "parts" and "%" are by weight unless otherwise specified.

[0055] [Production Example 1] Preparation of Base Polymer 1 In a 500 mL three-neck flask-type reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser, 30 parts by weight of 2-ethylhexyl acrylate, 70 parts by weight of methyl acrylate, 10 parts by weight of acrylic acid, and 0.2 parts by weight of benzoyl peroxide were put in. Next, the mixture was stirred while introducing nitrogen gas for about 1 hour, and the air inside was replaced with nitrogen. After that, the inside temperature was raised to 60°C, and polymerization was carried out by maintaining this state for about 6 hours, to obtain a polymer solution. The weight average molecular weight of this polymer measured by gel permeation chromatography (GPC) was 1.2 million.

[0056] [Example 1] A pressure-sensitive adhesive layer-forming composition was obtained by mixing 100 parts by weight of base polymer 1, 50 parts by weight of UV oligomer 1 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name: Shikoh UV-1700TL), 45 parts by weight of UV oligomer 2 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name: Shikoh UV-3000TL), 15 parts by weight of tackifier (manufactured by Yasuhara Chemical Co., Ltd., product name: M-G125), 0.2 parts by weight of light release agent (manufactured by Toho Chemical Industry Co., Ltd., product name: Phosphanol RL-210), 4.5 parts by weight of ionic liquid (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Elexel AS-110), 3 parts by weight of polymerization initiator (manufactured by GM Resins BV, product name: Omnirad 2959), 0.05 parts by weight of crosslinker 1 (manufactured by Mitsubishi Gas Chemical Co., Ltd., product name: TETRAD-C), and 5 parts by weight of crosslinker 2 (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate L") with toluene. Separately, an antistatic layer-forming composition containing 1 part by weight of 2-hydroxyethyltrimethylammonium hydroxide (choline) and 100 parts by weight of a solvent (a 1:1 (by weight) mixture of water and isopropyl alcohol) was applied to both sides of a substrate (manufactured by Nitto Denko Corporation, product name: polyethylene (PE) film, thickness: 150 μm) to form an antistatic layer with a thickness of 100 nm. The above adhesive composition was applied to one surface of the substrate on which the antistatic layer had been formed to form an adhesive layer having a thickness of 10 μm, thereby obtaining an adhesive sheet for processing semiconductor elements.

[0057] [Example 2] An adhesive sheet for processing semiconductor elements was obtained in the same manner as in Example 1, except that in the antistatic layer-forming composition, 1 part by weight of a quaternary ammonium salt (manufactured by Colcoat Co., Ltd., product name: Colcoat NR-121X-9) was used instead of choline.

[0058] Comparative Example 1 An adhesive sheet for processing semiconductor elements was obtained in the same manner as in Example 1, except that in the antistatic layer-forming composition, 1 part by weight of poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonic acid) (PDOT / PSS) (manufactured by Chukyo Yushi Co., Ltd., product name: U-940) was used instead of choline.

[0059] Comparative Example 2 A commercially available adhesive tape (Innox, product name: IPT-S10PLA-E1) was used.

[0060] <Evaluation 1> The adhesive sheets for processing semiconductor elements obtained in the examples and comparative examples were subjected to the following evaluations. The results are shown in Table 1. 1.Surface resistivity The surface resistance values ​​of the substrate and the adhesive layer were measured according to JIS K 6911. Specifically, a probe was pressed against the adhesive layer side surface or the substrate side surface of the obtained adhesive sheet for processing semiconductor elements, and a stable value was read after 30 seconds. The measurement was performed under the following measurement conditions. <Measurement conditions> Resistance meter: Hirester MCP-HT450 (manufactured by Mitsubishi Chemical) Probe: URS Temperature: 23±2℃ Humidity: 50±5%RH

[0061] 2. Surface resistivity ρs when 10V is applied 10VBM and ρ 10VPA and surface resistivity ρs when 1000V is applied 1000VBM and ρ 1000VPA A voltage of 10 V was applied for 1 minute or 1000 V was applied for 1 minute to the adhesive sheet for processing semiconductor elements obtained in the examples or comparative examples using a product (manufactured by Mitsubishi Chemical Corporation, product name: Hiresta MCP-HT450). Then, the surface resistance values ​​of the substrate and adhesive layer were measured in accordance with JIS K 6911. Specifically, a probe was pressed against the adhesive layer side surface or substrate side surface of the obtained adhesive sheet for processing semiconductor elements, and a stable value was read after 30 seconds had elapsed. The measurement was performed under the following measurement conditions. <Measurement conditions> Resistance meter: Hirester MCP-HT450 (manufactured by Mitsubishi Chemical) Probe: URS Temperature: 23±2℃ Humidity: 50±5%RH

[0062] 3. Surface resistivity after exposure to high humidity The adhesive sheet for processing semiconductor elements obtained in the examples or comparative examples was left to stand for 3 days under conditions of 40°C and 92% RH. After standing, the surface resistance values ​​of the substrate and adhesive layer were measured in accordance with JIS K 6911. Specifically, a probe was pressed against the adhesive layer side surface or substrate side surface of the obtained adhesive sheet for processing semiconductor elements, and a stable value was read after 30 seconds had elapsed. The measurement was performed under the following measurement conditions. <Measurement conditions> Resistance meter: Hirester MCP-HT450 (manufactured by Mitsubishi Chemical) Probe: URS Temperature: 23±2℃ Humidity: 50±5%RH Similarly, the adhesive sheets for processing semiconductor elements obtained in the Examples and Comparative Examples were left to stand for 3 days under conditions of 60° C. and 95% RH. After standing, the surface resistance values ​​of the substrate and the adhesive layer were measured in accordance with JIS K 6911.

[0063] [Table 1]

[0064] <Evaluation 2> Charge amount after chuck table peeling A silicon wafer (manufactured by Shin-Etsu Chemical Co., Ltd.) was attached to the adhesive layer side surface of the adhesive sheet for semiconductor element processing of Example 1, and dicing was performed using a dicing device (manufactured by DISCO Co., Ltd.). Thereafter, the adhesive sheet for semiconductor element processing was peeled off from the chuck table. Next, the charge amount of the adhesive layer surface and the substrate surface of the adhesive sheet for semiconductor element processing was measured for 1 second using a digital low potential meter (manufactured by Kasuga Electric Co., Ltd., product name: KSD-0202). The charge amount of the substrate surface was 0.0V, and the charge amount of the adhesive layer surface was 0.1V, and charging was prevented on both surfaces.

[0065] <Evaluation 3> Charge amount after scratching Evaluation was performed using the adhesive sheet for semiconductor element processing of Example 1 and the commercially available adhesive tape of Comparative Example 2. The adhesive sheet substrate that had been diced in the same manner as in Evaluation 2 was scratched by moving a rubber back and forth 10 times. The charge amount of the substrate surface was measured for 1 second using a digital low potential meter (manufactured by Kasuga Electric Co., Ltd., product name: KSD-0202) at the 0th, 3rd, 7th, and 10th times. All measured values ​​of the adhesive sheet for semiconductor element processing of Example 1 were 0V. On the other hand, the charge amount of the commercially available adhesive tape of Comparative Example 2 was 0V at the 0th time, but increased to 200V at the 3rd time, 450V at the 7th time, and 850V at the 10th time.

[0066] <Evaluation 4> Charge amount during pickup A dicing process was carried out in the same manner as in Evaluation 2 using the adhesive sheet for semiconductor element processing of Example 1. Next, a needle was continuously pushed up from the substrate surface to remove the diced wafers from the adhesive sheet. The charge amounts of the adhesive layer side and substrate layer side of the portion of the adhesive sheet for semiconductor element processing from which the diced wafers had been removed, as well as the removed diced wafers and adjacent wafers, were measured for 1 second using a digital low potential meter (manufactured by Kasuga Electric Co., Ltd., product name: KSD-0202). The charge amounts of the adhesive sheet for semiconductor element processing of Example 1 were 0V for the adhesive layer, 0V for the substrate, and 0V for the adjacent layer. Note that a general adhesive tape without antistatic properties (all of which had a surface resistivity of 1.0×10 measured in the above Evaluation 1) was used. 14 When a similar measurement was performed using a tape with a resistance of 1000V or more (exceeding Ω / □), the charge on the adhesive tape was 1,300V for the adhesive layer, 1,200V for the substrate, and 1,400V for the adjacent layer. [Industrial Applicability]

[0067] The pressure-sensitive adhesive sheet for processing semiconductor elements of the present invention can be suitably used for processing semiconductor elements in the transport process of the semiconductor elements. [Explanation of symbols]

[0068] 10 Base material 20 Adhesive layer 100 Adhesive sheet for semiconductor element processing

Claims

1. A substrate and a pressure-sensitive adhesive layer are included, The surface resistivity ρs of the substrate ＢＭ and the surface resistivity ρs of the pressure-sensitive adhesive layer ＰＡ is 1.0 x 10 １３ Ω / □ or less, The surface resistivity ρs of the substrate when 10 V is applied １０ＶＢＭ and the surface resistivity ρs of the pressure-sensitive adhesive layer when 10 V is applied １０ＶＰＡ and the surface resistivity ρs of the substrate when 1000 V is applied １０００ＶＢＭ and the surface resistivity ρs of the pressure-sensitive adhesive layer when 1000 V is applied １０００ＶＰＡ and satisfy the following formula (1) and formula (2): ρs １０００ＶＢＭ / ρs １０ＶＢＭ ≦1000 (1) ρs １０００ＶＰＡ / ρs １０ＶＰＡ ≦1000 (2)

2. A substrate and a pressure-sensitive adhesive layer are included, The surface resistivity ρs of the substrate ＢＭ and the surface resistivity ρs of the pressure-sensitive adhesive layer ＰＡ is 1.0 x 10 １３ Ω / □ or less, The surface resistivity ρs of the substrate at a humidity of 92% ９２％ＢＭ and the surface resistivity ρs of the pressure-sensitive adhesive layer at a humidity of 92% ９２％ＰＡ An adhesive sheet for processing semiconductor elements, which satisfies the following formula (3) and formula (4): ρs ９２％ＢＭ / ρs ＢＭ ≦1000 (3) ρs ９２％ＰＡ / ρs ＰＡ ≦1000 (4)

3. The adhesive sheet for processing semiconductor elements according to claim 1 or 2, wherein the adhesive layer contains an ionic liquid.

4. The adhesive sheet for processing semiconductor elements according to claim 3, wherein the content of the ionic liquid in the composition forming the adhesive layer is 0.1% by weight to 50% by weight.

5. The substrate has an antistatic layer on at least one surface thereof, 5. The adhesive sheet for processing semiconductor elements according to claim 1, wherein the antistatic layer contains a quaternary ammonium salt.

6. 6. The adhesive sheet for processing semiconductor elements according to claim 5, wherein the content of the quaternary ammonium salt in the composition forming the antistatic layer is 0.1% by weight to 50% by weight.

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