TW202233781A - adhesive sheet - Google Patents

Abstract

The present invention provides an adhesive sheet which exhibits adequate adhesiveness to a semiconductor chip and a sealing resin that seals the semiconductor chip, and which is not likely to leave adhesive residue when removed, while being able to be easily removed from the sealing resin. An adhesive sheet according to the present invention is provided with a base material and an adhesive layer that is arranged on at least one side of the base material; the adhesive layer contains an acrylic adhesive; and the acrylic adhesive contains a base polymer that has an acid value of 16 mgKOH/g or less. According to one embodiment of the present invention, the adhesive sheet is provided with the base material, the adhesive layer that is arranged on one side of the base material, and a second adhesive layer that is arranged on the reverse side of the base material from the adhesive layer.

Description

adhesive sheet

The present invention relates to an adhesive sheet.

In recent years, in order to prevent damage to the semiconductor wafer, spread metal wiring, and the like when manufacturing a semiconductor component including a semiconductor wafer, an operation of sealing the semiconductor wafer with a resin is sometimes performed. In the resin sealing step, from the viewpoint of workability and the like, an operation of sealing a semiconductor wafer with a resin may be performed on an adhesive sheet. For example, a plurality of semiconductor chips are arranged on a specific adhesive sheet as a temporary fixing material, and the semiconductor chips are once sealed on the adhesive sheet to prevent the semiconductor chips from moving. Thereafter, in a specific subsequent step, the above-mentioned adhesive sheet is peeled off from the resin in which the semiconductor chip is sealed.

In the above-mentioned steps, if the conventional adhesive sheet is used, there is a problem that the adhesive remains on the structure when the adhesive sheet is peeled off from the structure including the sealing resin and the semiconductor wafer. [Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2001-308116 Patent Document 2: Japanese Patent Laid-Open No. 2001-313350 Patent Document 3: Japanese Patent Laid-Open No. 2018-193563

[Problems to be Solved by Invention]

The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to provide an adhesive sheet which has moderate adhesiveness to a sealing resin for sealing a semiconductor chip and a semiconductor wafer, can be easily peeled off from the sealing resin, and is less likely to produce paste when peeled off. agent residues. [Technical means to solve problems]

The adhesive sheet of the present invention comprises a base material and an adhesive layer disposed on at least one side of the base material, the adhesive layer contains an acrylic adhesive, and the acrylic adhesive contains a base with an acid value of 16 mgKOH/g or less polymer. In one embodiment, the above-mentioned adhesive sheet includes: the above-mentioned substrate, the above-mentioned adhesive layer arranged on one side of the substrate, and a second adhesive arranged on the opposite side of the substrate and the adhesive layer Floor. In one embodiment, the shear adhesion force B at 150° C. when the above-mentioned adhesive layer is attached to the silicon wafer is relative to that at 23° C. when the above-mentioned adhesive layer is attached to polyethylene terephthalate. The ratio of adhesion force A (shear adhesion force B/adhesion force A) is 32.0 g/(N/20 mm) or more. In one embodiment, the above-mentioned base polymer is a cross-linked body of an acrylic polymer. In one embodiment, the gel fraction of the adhesive layer is 75% or more. In one embodiment, the acrylic adhesive includes a crosslinking agent, and the compounding amount of the crosslinking agent relative to the carboxyl group of the acrylic polymer is 0.08 mol equivalent to 2 mol equivalent. In one embodiment, the above-mentioned cross-linking agent is an epoxy-based cross-linking agent. In one embodiment, the amount of nitrogen gas generated when the adhesive layer is heated is 0.05 wt % to 1.0 wt %. In one embodiment, the thickness of the adhesive layer is 1 μm˜300 μm. In one embodiment, the above-mentioned adhesive sheet is a temporary fixing material used in the resin sealing step of the semiconductor chip. In one embodiment, the above-mentioned adhesive sheet is used when the sealing resin is hardened on the adhesive sheet. [Effect of invention]

According to the present invention, an adhesive sheet can be provided which has moderate adhesiveness to the sealing resin for sealing the semiconductor chip and the semiconductor wafer, can be easily peeled from the sealing resin, and is less likely to leave paste residue during peeling.

A. Outline of Adhesive Sheet FIG. 1 is a schematic cross-sectional view of an adhesive sheet according to an embodiment of the present invention. The adhesive sheet 100 includes a substrate 10 and an adhesive layer (first adhesive layer) 20 arranged on at least one side of the substrate 10 .

The adhesive sheet of the present invention can be preferably used as a temporary fixing material when resin-sealing a semiconductor wafer. More specifically, in the adhesive sheet of the present invention, semiconductor chips are arranged on the adhesive layer of the adhesive sheet, the semiconductor chips are covered with resin (usually epoxy resin), and the sealing resin is cured by curing the sealing resin. The semiconductor wafer is sealed with resin, and can be used as a temporary fixing material for the semiconductor wafer at this time. After sealing the semiconductor wafer with resin, in specific subsequent steps (such as backside grinding of the sealing resin, patterning, bump formation, and dicing (dicing into wafers)), the above-mentioned adhesive sheet can be separated from the sealing resin and the semiconductor wafer. The constituent structures are peeled off. The epoxy equivalent of the sealing resin is, for example, 50 g/eq to 500 g/eq.

The said adhesive layer contains an acrylic adhesive. The acrylic adhesive contains a base polymer with an acid value of 16 mgKOH/g or less. This means that the components in the adhesive layer have less residual carboxyl groups. In the present invention, by reducing the residual carboxyl groups of the components in the adhesive layer, the compatibility between the sealing resin and the components of the adhesive layer can be reduced, and as a result, paste residues can be prevented when the adhesive sheet is peeled off from the sealing resin. In addition, by reducing the residual carboxyl groups of the components in the adhesive layer, the cohesive force of the acrylic adhesive can be improved, and as a result, it has better adhesive force even under high temperature (such as the heating environment in the resin sealing step). The semiconductor chip can be fixed with a high fixing force during resin sealing. It is one of the great achievements of the present invention to obtain an adhesive sheet which has excellent fixability at high temperature, prevents paste residue and is excellent in peelability.

2 is a schematic cross-sectional view of an adhesive sheet according to another embodiment of the present invention. The adhesive sheet 200 further includes a second adhesive layer on the opposite side of the base material 10 from the adhesive layer 20 . That is, the adhesive sheet 200 includes the adhesive layer 20 , the base material 10 , and the second adhesive layer 30 in this order. By providing the 2nd adhesive bond layer 30, when performing resin sealing on a stage, the 2nd adhesive bond layer 30 side is stuck to this stage, and the adhesive sheet 200 can be arrange|positioned with good fixability.

In one embodiment, the second adhesive layer includes thermally expandable microspheres. The heat-expandable microspheres can expand at a specific temperature. By heating the adhesive layer containing such heat-expandable microspheres to a predetermined temperature or higher, the heat-expandable microspheres expand, resulting in unevenness on the adhesive surface (ie, the surface of the second adhesive layer), and the adhesive force decreases or disappears. When the second adhesive layer containing the thermally expandable microspheres is formed, the adhesiveness required when the adhesive sheet is fixed (for example, to a stage) can be exhibited, and when the adhesive sheet is peeled off (for example, peeled off from the stage) It exhibits good peelability due to the decrease or disappearance of the heating adhesive force.

The adhesive force A of the adhesive sheet of the present invention at 23° C. when the adhesive layer is attached to polyethylene terephthalate is preferably 0.05 N/20 mm to 1 N/20 mm, more preferably 0.05 N/20 mm to 10 N/20 mm, more preferably 0.05 N/20 mm to 5 N/20 mm, more preferably 0.1 N/20 mm to 2 N/20 mm, most preferably 0.1 N/20 mm ~1N/20mm. Within such a range, an adherend (eg, a semiconductor wafer) can be favorably fixed, and an adhesive sheet can be obtained that has less paste residue when peeled off. Furthermore, in this specification, the so-called "adhesive force at 23°C when the adhesive layer is attached to polyethylene terephthalate" refers to the following adhesive force: on the polyethylene terephthalate film (Thickness 25 μm) Laminate the adhesive layer of the adhesive sheet (width 20 mm × length 100 mm) (lamination conditions: roll back and forth with a 2 kg roller for 1 time), and place it at an ambient temperature of 23 ° C for 30 minutes Then, the sample was subjected to a tensile test (peeling speed: 300 mm/min, peeling angle 180°) and measured.

The shear adhesion force B at 150° C. of the adhesive sheet of the present invention when the adhesive layer is attached to the silicon wafer is preferably 500 g or more, more preferably 700 g to 1500 g, and more preferably 800 g to 1200 g . Within this range, the cohesive force of the acrylic adhesive is high, and even at a high temperature (for example, a heating step for hardening the sealing resin), it has a good adhesive force, and can prevent the adhesive from being placed on the adhesive sheet. The adherend (for example, a semiconductor wafer) is displaced in position. The shear adhesion force can be measured by the following method: after vertically attaching a mirror surface of a silicon wafer (size: 5 mm × 5 mm) on the adhesive layer without touching the corner of the wafer, heating at 130°C for 30 minutes The silicon wafer is adhered to the surface of the adhesive, and then, at the measurement temperature (150°C in the case of the shear adhesion force B measurement), an external force is applied in a direction horizontal to the wafer at a shear rate of 500 μm/sec. A load-displacement curve is obtained from which the maximum failure load is read.

The shear adhesion force B (hereinafter also referred to as shear adhesion force B) at 150°C when the adhesive layer is attached to the silicon wafer is 23 when the adhesive layer is attached to polyethylene terephthalate. The ratio of the adhesion force A (hereinafter also referred to as the adhesion force A) at ℃ (shear adhesion force B/adhesion force A) is preferably 32.0 g/(N/20 mm) or more, more preferably 150 g/(N /20 mm) or more, more preferably 1600 g/(N/20 mm) or more, particularly preferably 4000 g/(N/20 mm) or more. Within such a range, it is possible to prevent paste residue from occurring during peeling, and to prevent positional displacement (especially, positional displacement at high temperature) of the adherend.

The shear adhesion force of the adhesive sheet of the present invention at 190° C. when the adhesive layer is attached to the silicon wafer is preferably 300 g-1000 g, more preferably 350 g-750 g, and more preferably 400 g-600 g g. Within such a range, when the above-mentioned pressure-sensitive adhesive sheet includes a second pressure-sensitive adhesive layer containing heat-expandable microspheres, when the second pressure-sensitive adhesive layer side is made to express releasability, that is, heating is performed so that the When the heat-expandable microspheres expand, the adherend on the adhesive layer can be well fixed.

The thickness of the adhesive sheet of the present invention is preferably 3 μm to 300 μm, more preferably 5 μm to 150 μm, and still more preferably 10 μm to 100 μm.

B. Adhesive layer As mentioned above, the said adhesive layer contains an acrylic adhesive. The acrylic adhesive contains a base polymer with an acid value of 16 mgKOH/g or less. The acid value of the base polymer is preferably 10 mgKOH/g or less, more preferably 7.5 mgKOH/g or less, and still more preferably 5 mgKOH/g or less. Within such a range, the effect of the present invention is remarkable. The acid value of the base polymer is preferably as small as possible, and the lower limit is, for example, 0 mgKOH/g.

In this specification, the acid value of the above-mentioned base polymer is measured by the following method using the adhesive layer as a sample. In more detail, the acid value of the base polymer was measured as follows: after the adhesive layer was swelled with chloroform, excess methanol was added to separate it into soluble matter (sol) and insoluble matter (gel), and filter paper Filtration was carried out to recover the insoluble matter; this operation was carried out, and the acid value of the insoluble matter obtained after drying was measured. The acid value can be measured by potentiometric titration in accordance with JIS K 2501. The acid value of the base polymer can be adjusted to an appropriate range by adding a crosslinking agent capable of reacting with the carboxyl group of the base polymer to crosslink the base polymer while consuming the carboxyl group. In addition, in this specification, the so-called "base polymer" contained in the acrylic adhesive in the adhesive layer means a polymer formed by crosslinking a prepolymer (uncrosslinked polymer).

The gel fraction of the adhesive layer is preferably 75% or more, more preferably 85% or more, and still more preferably 90% or more. Within such a range, an adhesive layer formed by preferably adjusting the amount of carboxyl groups of the base polymer by crosslinking can be obtained. The higher the gel fraction of the adhesive layer, the better, and the upper limit is, for example, 99%. In addition, the gel fraction was obtained by (dry weight after immersion/dry weight before immersion)×100 after immersing the crosslinked adhesive layer in toluene for 7 days.

The amount of nitrogen gas generated when the adhesive layer is heated is preferably 0.05 wt% to 1.0 wt%, more preferably 0.07 wt% to 0.8 wt%, and still more preferably 0.15 wt% to 0.7 wt%. When the amount of nitrogen gas generated during the heat treatment of the adhesive layer is in this range, the carboxyl group of the base polymer is cross-linked and consumed, and the compatibility with the sealing resin is low, resulting in less paste residue. the adhesive layer. The amount of nitrogen gas when the adhesive layer is subjected to heat treatment is determined as follows: about 5.0 mg to 10.0 mg of the adhesive layer is collected, placed on a ceramic board, weighed by a microbalance, and then decomposed by thermal decomposition of the sample. The furnace was heated at 800° C./oxidizing furnace at 900° C., and the amount of nitrogen gas generated was determined using a TN (total trace nitrogen analyzer) apparatus.

The thickness of the above-mentioned adhesive layer is preferably 1 μm to 300 μm, more preferably 2 μm to 300 μm, further preferably 3 μm to 150 μm, more preferably 4 μm to 100 μm, and more preferably 5 μm ~50 μm.

The elastic modulus of the adhesive layer measured by the nanoindentation method at 25°C is preferably less than 100 MPa, more preferably 0.1 MPa to 50 MPa, and still more preferably 0.1 MPa to 10 MPa. Within such a range, an adhesive sheet having moderate adhesive force can be obtained. The so-called elastic modulus measured by the nanoindentation method refers to the continuous measurement of the load applied to the indenter when the indenter is pressed into the sample and the indentation during the entire process including loading and unloading. Depth, the elastic modulus calculated from the obtained load load-indentation depth curve. In this specification, the so-called elastic modulus measured by nanoindentation method refers to the measurement obtained by the above method under the measurement conditions of load: 1 mN, load/unload speed: 0.1 mN/s, holding time: 1s modulus of elasticity.

The tensile modulus of elasticity of the adhesive layer at 25°C is preferably less than 100 MPa, more preferably 0.1 MPa to 50 MPa, and still more preferably 0.1 MPa to 10 MPa. Within such a range, an adhesive sheet having moderate adhesive force can be obtained. In addition, the tensile modulus of elasticity can be measured according to JIS K 7161:2008.

The probe tack value of the adhesive layer is preferably 50 N/5 mmϕ or higher, more preferably 75 N/5 mmϕ or higher, and more preferably 100 N/5 mmϕ or higher. Within such a range, positional displacement of the adherend (eg, semiconductor wafer) arranged on the adhesive sheet can be prevented. The measurement conditions of the probe viscosity value were set as follows: probe processing speed: 30 mm/min, test speed: 30 mm/min, contact load: 100 gf, contact retention time: 1 second, and probe area: 5 mmϕSUS.

The value of sp (Solubility Parameter) of the base polymer is preferably 7(cal/cm ³ ) ^1/2 to 10(cal/cm ³ ) ^1/2 , more preferably 7(cal/cm ³ ) ^{1 /2} to 9(cal/cm ³ ) ^1/2 , more preferably 7(cal/cm ³ ) ^1/2 to 8(cal/cm ³ ) ^1/2 . Within such a range, an adhesive sheet having moderate adhesiveness and less paste residue at the time of peeling can be obtained.

(acrylic adhesive) Examples of the above-mentioned acrylic adhesive include, for example, an acrylic adhesive using an acrylic polymer (homopolymer or copolymer) as a prepolymer, and a cross-linked body of the prepolymer as a base polymer, and the like. The acrylic polymer (homopolymer or copolymer) is obtained by using one or two or more types of alkyl (meth)acrylates as monomer components. In one embodiment, the above-mentioned base polymer has a cross-linked structure based on an acrylic polymer and an epoxy cross-linking agent.

Specific examples of the above-mentioned alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and isopropyl (meth)acrylate. , butyl (meth)acrylate, isobutyl (meth)acrylate, 2-butyl (meth)acrylate, 3-butyl (meth)acrylate, amyl (meth)acrylate, (meth)acrylate Hexyl acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, ( isononyl meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, (meth)acrylate ) Tridecyl acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate C1-20 alkyl esters of (meth)acrylates such as octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. Among them, alkyl (meth)acrylates having a linear or branched alkyl group having a carbon number of 4 to 20 (more preferably 6 to 20, particularly preferably 8 to 18) are preferred, and (meth)acrylates are more preferred. 2-ethylhexyl meth)acrylate.

In order to improve cohesion, heat resistance, crosslinking properties, etc., the above-mentioned acrylic polymer (prepolymer) may contain other monomer components which can be copolymerized with the above-mentioned alkyl (meth)acrylate, if necessary. the unit. Examples of such monomer components include carboxyl-containing groups such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Monomers; anhydride monomers such as maleic anhydride and itaconic anhydride; hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, (meth)acrylic acid Hydroxyhexyl, hydroxyoctyl (meth)acrylate, hydroxydecyl (meth)acrylate, hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl methacrylate, etc. body; styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate , (meth)acryloyloxynaphthalenesulfonic acid and other monomers containing sulfonic acid groups; (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (methyl) (N-substituted) amide monomers such as acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, etc.; (meth)acrylate amine Aminoalkyl (meth)acrylate monomers such as ethyl ethyl ester, N,N-dimethylaminoethyl (meth)acrylate, tert-butylaminoethyl (meth)acrylate, etc.; ( (meth)acrylic acid alkoxyalkyl ester monomers such as methoxyethyl meth)acrylate and ethoxyethyl (meth)acrylate; N-cyclohexylmaleimide, N- Isopropyl maleimide, N-lauryl maleimide, N-phenylmaleimide and other maleimide monomers; N-methyl Iconimide, N-Ethyl Iconimide, N-Butyl Iconimide, N-Octyl Iconimide, N-2-Ethylhexyl Iconimide, N -Iconimide monomers such as Cyclohexyl Iconimide, N-Lauryl Iconimide, etc.; Butadiimide such as meth)acryloyl-6-oxyhexamethylene butadiimide, N-(meth)acryloyl-8-oxyoctamethylene butadiimide, etc. Monomers; vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperidone, vinyl Ethylene such as pyridine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinylcarboxyamide, styrene, α-methylstyrene, N-vinylcaprolactam cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy-containing acrylic monomers such as glycidyl (meth)acrylate; polyethylene glycol (meth)acrylate, ( Glycol acrylate monomers such as polypropylene glycol meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; tetrahydrofurfuryl (meth)acrylate , fluorinated (meth)acrylate, (meth)acrylate silicone ester and other acrylate monomers containing heterocycles, halogen atoms, silicon atoms, etc.; hexanediol di(meth)acrylate, (poly) Ethylene glycol bis(methyl) Acrylates, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol Multifunctional monomers such as tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, urethane acrylate; isoprene, butadiene, Olefin-based monomers such as isobutylene; vinyl ether-based monomers such as vinyl ether, etc. These monomer components may be used alone or in combination of two or more.

In one embodiment, the above-mentioned acrylic polymer (prepolymer) further includes a structural unit derived from a hydroxyl group-containing monomer. By using the acrylic polymer including the structural unit derived from the hydroxyl group-containing monomer, the interaction with the sealing resin becomes small compared to the acrylic polymer including the structural unit derived from the carboxyl group-containing monomer, so Paste residue can be suppressed. The content of the structural unit derived from the hydroxyl group-containing monomer is preferably 0.1% by weight to 20% by weight, more preferably 0.5% by weight to 10% by weight, particularly preferably 1 % by weight to 7% by weight.

The said acrylic adhesive may contain arbitrary appropriate additives as needed. As the additive, for example, a crosslinking agent, an adhesion imparting agent, a plasticizer (for example, a trimellitic acid ester-based plasticizer, a pyromellitic acid ester-based plasticizer, etc.), pigments, dyes, fillers, etc. may be mentioned. agent, anti-aging agent, conductive material, antistatic agent, ultraviolet absorber, light stabilizer, peeling regulator, softener, surfactant, flame retardant, antioxidant, etc.

Examples of the crosslinking agent contained in the acrylic adhesive include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, and urea-based crosslinking agents. agent, metal alkoxide-based cross-linking agent, metal chelate-based cross-linking agent, metal salt-based cross-linking agent, carbodiimide-based cross-linking agent, oxazoline-based cross-linking agent, aziridine-based cross-linking agent Linking agent, amine crosslinking agent, etc.

In one embodiment, the compounding amount of the crosslinking agent relative to the carboxyl group of the acrylic polymer (prepolymer) is preferably 0.08 mol equivalent to 2 mol equivalent, more preferably 0.3 mol equivalent to 1.6 mol equivalent equivalent. Within such a range, an adhesive sheet with less residual carboxyl groups of components in the adhesive layer can be obtained. Here, the compounding amount of the crosslinking agent means the content of the crosslinking agent before the crosslinking of the acrylic polymer.

Specific examples of the above-mentioned isocyanate-based crosslinking agent contained in the above-mentioned acrylic adhesive include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; cyclopentylene diisocyanate, Cyclohexylene diisocyanate, isophorone diisocyanate and other alicyclic isocyanates; 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate and other aromatic isocyanates ; Trimethylolpropane/toluene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry, trade name "Coronate L"), trimethylolpropane/hexamethylene diisocyanate trimer adduct ( Isocyanate adducts such as Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HL"), isocyanurate of hexamethylene diisocyanate (Nippon Polyurethane Industry, trade name "Coronate HX") and the like. The compounding amount of the isocyanate-based crosslinking agent can be set to any suitable amount according to the required adhesive force, with respect to 100 parts by weight of the acrylic polymer, typically 0.1 part by weight to 20 parts by weight, more preferably 1 part by weight ~10 parts by weight. Within such a range, an adhesive sheet with less residual carboxyl groups of components in the adhesive layer can be obtained. Here, the compounding amount of the crosslinking agent means the content of the crosslinking agent before the crosslinking of the acrylic polymer.

In one embodiment, as the above-mentioned cross-linking agent, an epoxy-based cross-linking agent is preferably used. If an epoxy-based crosslinking agent is used, an adhesive layer with a high cohesive force can be formed, and the positional displacement of the adherend can be prevented more effectively.

As the epoxy-based crosslinking agent contained in the acrylic adhesive, for example, N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidylaniline, 1, 3-bis(N,N-glycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C"), 1,6-hexanediol diglycidyl ether (Kyoeisha Chemical Co., Ltd. manufactured by the company, trade name "Epolight 1600"), neopentyl glycol diglycidyl ether (manufactured by Kyeisha Chemical Co., Ltd., trade name "Epolight 1500NP"), ethylene glycol diglycidyl ether (manufactured by Kyeisha Chemical Co., Ltd., Trade name "Epolight 40E"), propylene glycol diglycidyl ether (manufactured by Kyeisha Chemical Co., Ltd., trade name "Epolight 70P"), polyethylene glycol diglycidyl ether (manufactured by NOF Corporation, trade name "EPIOL E-400" ”), polypropylene glycol diglycidyl ether (manufactured by NOF Corporation, trade name “EPIOL P-200”), sorbitol polyglycidyl ether (manufactured by Nagase chemteX, trade name “DENACOL EX-611”), glycerin polyglycidyl Glyceryl ether (manufactured by Nagase chemteX, trade name "DENACOL EX-314"), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (manufactured by Nagase chemteX, trade name "DENACOL EX-512"), sorbitan polyglycidyl ether Glycidyl ether, trimethylolpropane polyglycidyl ether, diglycidyl adipate, diglycidyl phthalate, triglycidyl tris(2-hydroxyethyl) isocyanurate, isophthalic acid Phenol diglycidyl ether, bisphenol-S-diglycidyl ether, epoxy resins having two or more epoxy groups in the molecule, and the like. The compounding amount of the epoxy-based crosslinking agent can be set to any suitable amount according to the required adhesive force, with respect to 100 parts by weight of the acrylic polymer, typically 0.01 parts by weight to 50 parts by weight, more preferably 1 part by weight parts by weight to 30 parts by weight, more preferably 2 parts by weight to 20 parts by weight, particularly preferably 3 parts by weight to 15 parts by weight. Within such a range, an adhesive sheet with less residual carboxyl groups of components in the adhesive layer can be obtained. Here, the compounding amount of the crosslinking agent means the content of the crosslinking agent before the crosslinking of the acrylic polymer.

In one embodiment, an N atom-containing crosslinking agent is used as the epoxy-based crosslinking agent. If a crosslinking agent containing N atoms is used, it is advantageous in that the crosslinking reaction is accelerated by the action of a catalyst, and the adhesive is easily gelled.

Any suitable adhesion-imparting agent can be used as the above-mentioned adhesion-imparting agent contained in the above-mentioned acrylic adhesive. As the adhesion imparting agent, for example, an adhesion imparting resin can be used. Specific examples of the adhesion-imparting resins include rosin-based adhesion-imparting resins (for example, unmodified rosin, modified rosin, rosin phenol-based resins, rosin ester-based resins, etc.), terpene-based adhesion-imparting resins (for example, terpenes). olefin-based resin, terpene-phenol-based resin, styrene-modified terpene-based resin, aromatic-modified terpene-based resin, hydrogenated terpene-based resin), hydrocarbon-based adhesion-imparting resin (such as aliphatic hydrocarbon resin, aliphatic Cyclic hydrocarbon resins, aromatic hydrocarbon resins (such as styrene resins, xylene resins, etc.), aliphatic-aromatic petroleum resins, aliphatic-alicyclic petroleum resins, hydrogenated hydrocarbon resins, benzos Furan-based resins, benzofuran-indene-based resins, etc.), phenol-based adhesion-imparting resins (such as alkylphenol-based resins, xylaldehyde-based resins, resole, novolak, etc.), ketone-based adhesion-imparting resins, polyphenolic Amine based adhesion imparting resin, epoxy based adhesion imparting resin, elastic system adhesion imparting resin, etc. Among them, rosin-based tackifying resins, terpene-based tackifying resins, or hydrocarbon-based tackifying resins (styrene-based resins, etc.) are preferred. The adhesion imparting agent may be used alone or in combination of two or more. The addition amount of the adhesion imparting agent is preferably 5 parts by weight to 100 parts by weight, more preferably 8 parts by weight to 50 parts by weight, relative to 100 parts by weight of the base polymer.

It is preferable to use a resin with a relatively high softening point or glass transition temperature (Tg) as the above-mentioned adhesion imparting resin. If a resin with a high softening point or glass transition temperature (Tg) is used, an adhesive layer that can exhibit high adhesion even in a high temperature environment (eg, in a high temperature environment such as processing during sealing of semiconductor wafers) can be formed. The softening point of the adhesion imparting agent is preferably 100°C to 180°C, more preferably 110°C to 180°C, and still more preferably 120°C to 180°C. The glass transition temperature (Tg) of the adhesion imparting agent is preferably 100°C to 180°C, more preferably 110°C to 180°C, and still more preferably 120°C to 180°C.

It is preferable to use a low-polarity adhesion-imparting resin as the above-mentioned adhesion-imparting resin. If a low-polarity adhesion-imparting resin is used, an adhesive layer with low affinity with the sealing material can be formed. Examples of low-polarity adhesion-imparting resins include aliphatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aromatic hydrocarbon resins (eg, styrene-based resins, xylene-based resins, etc.), aliphatic/aromatic Hydrocarbon-based adhesion imparting resins such as family-based petroleum resins, aliphatic/alicyclic petroleum resins, and hydrogenated hydrocarbon resins. Among them, an adhesion imparting agent having 5 to 9 carbon atoms is preferable. The reason for this is that such an adhesion-imparting agent is not only low in polarity, but also has excellent compatibility with acrylic polymers, does not undergo phase separation in a wide temperature range, and can form an adhesive layer with excellent stability.

The acid value of the adhesion-imparting resin is preferably 40 or less, more preferably 20 or less, and still more preferably 10 or less. Within such a range, an adhesive layer having a low affinity with the sealing material can be formed. The hydroxyl value of the adhesion-imparting resin is preferably 60 or less, more preferably 40 or less, and still more preferably 20 or less. Within such a range, an adhesive layer having a low affinity with the sealing material can be formed.

C. Substrates As the above-mentioned substrates, for example, resin sheets, non-woven fabrics, paper, metal foils, woven fabrics, rubber sheets, foamed sheets, and laminates thereof (especially those containing resin sheets can be exemplified) laminate), etc. As resin constituting the resin sheet, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), wholly aromatic polyamide (aramid), polyimide (PI) ), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), fluorine-based resin, polyether ether ketone (PEEK), etc. Examples of non-woven fabrics include non-woven fabrics made of natural fibers having heat resistance, such as non-woven fabrics including Manila hemp, and synthetic resin non-woven fabrics such as polypropylene resin non-woven fabrics, polyethylene resin non-woven fabrics, and ester-based resin non-woven fabrics. As metal foil, copper foil, stainless steel foil, aluminum foil, etc. are mentioned. As paper, Japanese paper, kraft paper, etc. are mentioned.

The thickness of the above-mentioned base material can be set to any suitable thickness according to the required strength, flexibility, and purpose of use. The thickness of the substrate is preferably 1000 μm or less, more preferably 1 μm to 1000 μm, further preferably 1 μm to 500 μm, particularly preferably 3 μm to 300 μm, and most preferably 5 μm to 250 μm.

The above-mentioned base material may also be subjected to surface treatment. As the surface treatment, for example, corona treatment, chromic acid treatment, ozone exposure, flame exposure, high voltage electric shock exposure, ionizing radiation treatment, treatment of coating a primer layer, etc. may be mentioned.

As the above-mentioned organic coating material, for example, the material described in Plastic Hard Coating Material II (CMC Publishing, (2004)) can be exemplified. Preferably, urethane-based polymers are used, and more preferably, polyacrylate urethane, polyester urethane, or these precursors are used. The reason is that the coating and coating on the substrate are simple, and there are many kinds of industrial products to choose from, and the acquisition cost is low. The urethane-based polymer is, for example, a polymer comprising a reaction mixture of an isocyanate monomer and an alcoholic hydroxyl group-containing monomer (eg, a hydroxyl group-containing acrylic compound or a hydroxyl group-containing ester compound). The organic coating material may also contain chain extenders such as polyamines, anti-aging agents, oxidation stabilizers, etc. as optional additives. The thickness of the organic coating is not particularly limited, for example, it is preferably about 0.1 μm to 10 μm, preferably about 0.1 μm to 5 μm, and more preferably about 0.5 μm to 5 μm.

D. 2nd adhesive layer The said 2nd adhesive layer can be an adhesive layer which consists of any suitable adhesive. In one embodiment, as described above, the second adhesive layer further includes thermally expandable microspheres.

The adhesive contained in the second adhesive layer may be a curable adhesive (eg, an active energy ray curable adhesive) or a pressure-sensitive adhesive. As a pressure-sensitive adhesive, an acrylic adhesive, a rubber-type adhesive, etc. are mentioned, for example. Details of the adhesive contained in the second adhesive layer can be referred to, for example, the description of Japanese Patent Laid-Open No. 2018-009050. The full text of the publication is incorporated by reference in this specification.

As the thermally expandable microspheres, any suitable thermally expandable microspheres can be used as long as the microspheres can be expanded or foamed by heating. As the above-mentioned thermally expandable microspheres, for example, microspheres formed by enclosing a substance that is easily expandable by heating in an elastic shell can be used. Such heat-expandable microspheres can be produced by any appropriate method, for example, a coacervation method, an interfacial polymerization method, or the like.

Examples of substances that can be easily expanded by heating include propane, propylene, butene, n-butane, isobutane, isopentane, neopentane, n-pentane, n-hexane, isohexane, heptane, Octane, petroleum ether, halides of methane, tetraalkylsilanes and other low-boiling liquids; azodimethylamides which are vaporized after thermal decomposition, etc.

Examples of the material constituting the above-mentioned shell include nitrile monomers such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, and fumaric nitrile; acrylic acid, methacrylic acid, Iconic acid, maleic acid, fumaric acid, citraconic acid and other carboxylic acid monomers; vinylidene chloride; vinyl acetate; methyl (meth)acrylate, ethyl (meth)acrylate, n-Butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, cyclohexyl (meth)acrylate, (meth)acrylate (Meth)acrylates such as benzyl acrylate, β-carboxyethyl acrylate; styrene monomers such as styrene, α-methylstyrene, chlorostyrene; acrylamide, substituted acrylamide, methacrylamide A polymer composed of amide monomers such as amines and substituted methacrylamides. The polymer composed of these monomers may be a homopolymer or a copolymer. Examples of the copolymer include vinylidene chloride-methyl methacrylate-acrylonitrile copolymer, methyl methacrylate-acrylonitrile-methacrylonitrile copolymer, methyl methacrylate-acrylonitrile Copolymer, Acrylonitrile-Methacrylonitrile-Iconic Acid Copolymer, etc.

As the thermally expandable microspheres, an inorganic foaming agent or an organic foaming agent can be used. As an inorganic foaming agent, ammonium carbonate, ammonium hydrogencarbonate, sodium hydrogencarbonate, ammonium nitrite, sodium borohydride, various azides, etc. are mentioned, for example. In addition, as the organic foaming agent, for example, chlorofluoroalkane-based compounds such as trichloromonofluoromethane and dichloromonofluoromethane; azobisisobutyronitrile, azodimethylamide, azobis Azo compounds such as barium formate; p-toluenesulfohydrazine, diphenyl-3,3'-disulfohydrazine, 4,4'-oxybis(benzenesulfohydrazine), allylbis(sulfohydrazine) hydrazine) and other hydrazine compounds; p-toluenesulfonamidourea, 4,4'-oxybis (benzenesulfonamidourea) and other aminourea compounds; 5-morpholino-1,2,3, Triazole compounds such as 4-thitriazole; N,N'-dinitrosopentamethylenetetramine, N,N'-dimethyl-N,N'-dinitrosoterephthalide N-nitroso compounds such as amines, etc.

A commercial item can also be used for the said heat-expandable microsphere. Specific examples of commercially available heat-expandable microspheres include trade name "Matsumoto Microsphere" (grades: F-30, F-30D, F-36D, F-36LV, F- 50, F-50D, F-65, F-65D, FN-100SS, FN-100SSD, FN-180SS, FN-180SSD, F-190D, F-260D, F-2800D), the trade name manufactured by Japan's Fillite company "Expancel" (Grades: 053-40, 031-40, 920-40, 909-80, 930-120), "DAIFOAM" manufactured by Kureha Chemical Industry Co., Ltd. (Grades: H750, H850, H1100, S2320D, S2640D, M330 , M430, M520), "ADVANCELL" manufactured by Sekisui Chemical Industry Co., Ltd. (grades: EML101, EMH204, EHM301, EHM302, EHM303, EM304, EHM401, EM403, EM501), etc.

The particle size of the heat-expandable microspheres before heating is preferably 0.5 μm to 80 μm, more preferably 5 μm to 45 μm, further preferably 10 μm to 20 μm, particularly preferably 10 μm to 15 μm. Therefore, the particle size of the thermally expandable microspheres before heating is preferably 6 μm to 45 μm, more preferably 15 μm to 35 μm, in terms of the average particle diameter. The above-mentioned particle diameter and average particle diameter are values that can be determined by a particle size distribution measurement method in a laser scattering method.

It is preferable that the said heat-expandable microspheres have suitable intensity|strength so that they do not break until the volume expansion rate becomes preferably 5 times or more, more preferably 7 times or more, and still more preferably 10 times or more. In the case of using such heat-expandable microspheres, the adhesive force can be efficiently reduced by heat treatment.

The content ratio of the heat-expandable microspheres in the above-mentioned adhesive layer can be appropriately set according to the desired reduction of the adhesive force and the like. The content ratio of the heat-expandable microspheres is, for example, 1 part by weight to 150 parts by weight, preferably 10 parts by weight to 130 parts by weight, and more preferably 25 parts by weight relative to 100 parts by weight of the base polymer forming the second adhesive layer. parts to 100 parts by weight.

When the above-mentioned adhesive layer contains heat-expandable microspheres, the arithmetic surface roughness Ra of the adhesive layer before the expansion of the heat-expandable microspheres (that is, before heating) is preferably 500 nm or less, more preferably 400 nm or less, and further Preferably it is 300 nm or less. Within such a range, an adhesive sheet excellent in adhesion to an adherend can be obtained. Such an adhesive layer excellent in surface smoothness can be obtained, for example, by setting the thickness of the adhesive layer to the above-mentioned range.

When the above-mentioned adhesive layer contains thermally expandable microspheres, the above-mentioned adhesive layer preferably contains a dynamic storage modulus at 80°C in the range of 5 kPa to 1 MPa (more preferably 10 kPa to 0.8 MPa). Adhesive made from the base polymer. If it is such an adhesive layer, it can form the adhesive sheet which has moderate adhesiveness before heating, and the adhesive force is easily reduced by heating. Furthermore, the dynamic storage modulus can be measured under the measurement conditions of a frequency of 1 Hz and a heating rate of 10° C./min using a dynamic viscoelasticity measuring device (eg, trade name “ARES” manufactured by Rheometrics).

E. Manufacturing method of an adhesive sheet The adhesive sheet of this invention can be manufactured by any suitable method. For example, the adhesive sheet of the present invention can be exemplified by the method of directly coating the composition containing the acrylic adhesive on the substrate, or the method of coating the composition containing the acrylic adhesive on any suitable substrate. The method of transferring the coating layer to the substrate, etc. The composition containing the acrylic adhesive may contain any suitable solvent.

In the case of forming the adhesive layer containing the heat-expandable microspheres, the adhesive layer can be formed by coating a composition containing the heat-expandable microspheres, the adhesive and any suitable solvent on the substrate. Alternatively, the heat-expandable microspheres may be sprinkled on the adhesive coating layer, and the heat-expandable microspheres may be embedded in the adhesive using a laminating machine or the like to form an adhesive layer containing the heat-expandable microspheres.

As a coating method of the above-mentioned adhesive agent and each composition, any suitable coating method can be adopted. For example, each layer can be formed by drying after coating. As a coating method, the coating method using a multi-coater (Multi Coater), a die coater, a gravure coater, an applicator, etc. is mentioned, for example. As a drying method, natural drying, heat drying, etc. are mentioned, for example. In the case of heating and drying, the heating temperature can be set to any suitable temperature according to the properties of the material to be dried. [Example]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention should not be limited to the examples. The evaluation methods in the examples are as follows. In addition, in the Example, unless otherwise specified, "part" and "%" are based on weight.

(1) Acid value The acid value of the base polymer constituting the adhesive layer was measured by the following method. After a specific amount of the adhesive layer was swelled with chloroform, excess methanol was added to separate it into soluble matter (sol) and insoluble matter (gel), which were filtered with filter paper to recover the insoluble matter (this operation was performed three times in total), After drying, an insoluble matter (gel) was obtained, and this was used as a measurement sample. For this measurement sample, according to JIS K 2501, a potentiometric titration apparatus AT-500 N (manufactured by Kyoto Electronics Co., Ltd.), glass electrodes H-171 and R-173 (manufactured by Kyoto Electronics Co., Ltd.) as electrodes, The acid value was measured by potentiometric titration and used as the acid value of the base polymer. The measurement procedure is as follows: add the measurement sample and 200 mL of the mixed solvent to a 300 mL conical flask, make it swell, and then carry out titration. A blank test was performed by the same method, and the acid value was calculated according to the following formula (1). Acid value (mgKOH/g)=(V ₁ -V ₀ )×f×0.1×56.11/S・・・(1) S: Mass of sample collected (g) V ₀ : Titration required in blank test Amount of solution (mL) V ₁ : Amount of titration solution (mL) required for this test f: Coefficient of titration solution (f=1.002) Furthermore, the measurement conditions in the above measurement are as follows.・Titration solution: 0.1 mol/L KOH alcohol solution (commercially available) ・Mixed solvent: Toluene: Water: Isopropanol = 500: 5: 495 (width 20 mm x length 140 mm) on the entire surface opposite to the adhesive layer was attached to a SUS304 board via a double-sided tape (manufactured by Nitto Denko Co., Ltd., trade name "No. 531"). Next, a polyethylene terephthalate film (manufactured by Toray Co., Ltd., trade name "" Lumirror S-10”, thickness: 25 μm, width: 30 mm). The sample for evaluation obtained in the above manner was used for the tensile test. As a tensile tester, a trade name "Shimadzu Autograph AG-120kN" manufactured by Shimadzu Corporation was used. The tensile test was started after the sample for evaluation was installed in the tensile tester and left to stand at an ambient temperature of 23° C. for 30 minutes. The conditions of the tensile test were set as peeling angle: 180°, peeling speed (tensile speed): 300 mm/min. The load at the time of peeling the adhesive sheet from the PET film was measured, and the maximum load at that time was taken as the adhesive force of the adhesive sheet. (3) Shear Adhesion Using double-sided tape No. 585 manufactured by Nitto Denko Co., Ltd., the adhesive sheets (dimensions: 20 mm×20 mm) obtained in Examples 1 to 7 and the comparative example were mixed with an adhesive The surface on the opposite side of the layer (the second adhesive layer in Example 7) is attached and fixed on a specific stage (20 mm × 20 mm silicon wafer), and the 5 mm × 5 mm silicon wafer (mirror surface) is fixed with tweezers. It is vertically attached to the surface of the adhesive layer of the adhesive sheet so that the corner of the wafer does not contact the surface layer of the adhesive. Then, it heated at 130 degreeC for 30 minutes, the silicon wafer was made to adhere to the adhesive surface, and the sample for evaluation was produced. The samples for evaluation were measured at the measurement temperature (150°C, 190°C) using a dage 4000 manufactured by Nordson Corporation, mounted on the side of a 5 mm × 5 mm silicon wafer at a height of 250 μm from the attachment surface. A load-displacement curve was obtained by applying an external force in a direction horizontal to the wafer at a shear rate of 500 μm/sec. The maximum breaking load was read from the load-displacement curve and used as the shear bond strength. (4) The gel fraction collects about 0.5 g of adhesive layer (weight W1), wraps it into a purse with a porous PTFE membrane (weight W2) with an average pore size of 0.2 μm, and bundles it with kite string (weight W3). mouth. The purse was immersed in 50 mL of toluene, kept at room temperature (25° C.) for 7 days, only after the sol component in the adhesive layer was dissolved out of the above-mentioned film, the above-mentioned purse was taken out, and the toluene attached to the outer surface was wiped off, After drying the purse at 130° C. for 2 hours, the weight (W4) of the purse was measured. Then, the gel fraction was obtained by substituting each value into the following formula. Gel fraction (%)=[(W4－W2－W3)/W1]×100 (5) Nitrogen generation amount As for the amount of nitrogen gas generated when the adhesive layer is heated, the adhesive layer is collected and placed on the ceramic After the plate was weighed with a microbalance, the evaluation sample was determined using a TN (total nitrogen analyzer) apparatus. In addition, regarding the porcelain plate, the one that was preliminarily introduced into the apparatus and was fired in the air was used. The measurement was performed twice, and the average value was calculated. In addition, the measurement conditions in the said measurement are as follows.・Temperature: thermal decomposition furnace 800℃, oxidation furnace 900℃ ・Carrier gas: O ₂ (300 mL/min), Ar (300 mL/min) ・Standard sample: Pyridine/toluene solution ・Detector: reduced pressure chemiluminescence Detector Scope: High Concentration (6) Evaluation of Paste Residues A frame-shaped spacer ( Internal dimensions 25 mm × 95 mm), sprinkle a granular epoxy resin-based sealant (manufactured by Sumitomo Bakelite Co., G730) on the inside of the spacer in such a way that the thickness of the resin after hardening is 0.3 mm, and then cover the spacer. The silicone-treated release liner was then subjected to compression molding at 130°C for 600 seconds using a vacuum compression molding machine, and then heated at 140°C for 1 hour to harden, and the adhesive sheet was adhered to the adhesive sheet. A sealing resin is formed on the agent layer to form a structure. After cooling the structure obtained as described above, the adhesive sheet was peeled off from the structure using a tensile tester. After the structure was installed on the tensile tester, the tensile test was started in each temperature environment after standing at an ambient temperature of 23° C. or 80° C. for 30 minutes. The conditions of the tensile test were set as peeling angle: 180°, peeling speed (tensile speed): 300 mm/min. After peeling the adhesive sheet from the sealing resin, the residue of the paste on the attached surface of the structure was visually observed and evaluated under the following conditions. ◎: No paste residue was observed on the epoxy resin-based sealing material at both ambient temperatures of 23°C and 80°C ○: No paste was observed on the epoxy resin-based sealing material only at an ambient temperature of 80°C Residual ×: Residue of paste was observed on the epoxy resin sealant at an ambient temperature of 80°C

[Example 1] 100 parts by weight of acrylic copolymer A (copolymer of 2-ethylhexyl acrylate and acrylic acid, 2-ethylhexyl acrylate structural unit: acrylic structural unit=95:5 (weight ratio)), epoxy-based cross-linked 3 parts by weight of joint agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C"), 10 parts by weight of rosin-based adhesion imparting resin (manufactured by Sumitomo Bakelite Co., Ltd., trade name "SUMILITERESIN PR-12603"), and 100 parts by weight of toluene parts were mixed to prepare a composition for forming an adhesive layer. The composition for forming an adhesive layer was coated on one surface of a polyethylene terephthalate film (manufactured by Toray Corporation, trade name "Lumirror S10", thickness 38 μm) as a substrate to obtain a substrate and an adhesive. Adhesive sheet composed of layers (thickness 5 μm). The obtained adhesive sheet was used for the above-mentioned evaluations (1) to (6). The results are shown in Table 1.

[Example 2] Adhesion was obtained in the same manner as in Example 1, except that the compounding amount of the epoxy-based crosslinking agent was 5 parts by weight, and the rosin-based adhesion-imparting resin was not compounded to prepare a composition for forming an adhesive layer. Sheet. The obtained adhesive sheet was used for the above-mentioned evaluations (1) to (6). The results are shown in Table 1.

[Example 3] An adhesive sheet was obtained in the same manner as in Example 1, except that the compounding amount of the epoxy-based crosslinking agent was 5 parts by weight to prepare a composition for forming an adhesive layer. The obtained adhesive sheet was used for the above-mentioned evaluations (1) to (6). The results are shown in Table 1.

[Example 4] An adhesive sheet was obtained in the same manner as in Example 1, except that the compounding amount of the epoxy-based crosslinking agent was 10 parts by weight to prepare a composition for forming an adhesive layer. The obtained adhesive sheet was used for the above-mentioned evaluations (1) to (6). The results are shown in Table 1.

[Example 5] Acrylic copolymer B (copolymer of 2-ethylhexyl acrylate and hydroxyethyl acrylate, 2-ethylhexyl acrylate structural unit: hydroxyethyl acrylate structural unit=100:4 (weight ratio)) 100 weight 3 parts by weight of an isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Industry, trade name "Coronate L"), 10 parts by weight of a rosin-based tackifier resin (manufactured by Sumitomo Bakelite, trade name "SUMILITERESIN PR-12603") , and 100 parts by weight of toluene were mixed to prepare a composition for forming an adhesive layer. The composition for forming an adhesive layer was coated on one surface of a polyethylene terephthalate film (manufactured by Toray Corporation, trade name "Lumirror S10", thickness 38 μm) as a substrate to obtain a substrate and an adhesive. Adhesive sheet composed of layers (thickness 5 μm).

[Example 6] 100 parts by weight of acrylic copolymer A (copolymer of 2-ethylhexyl acrylate and acrylic acid, 2-ethylhexyl acrylate structural unit: acrylic structural unit=95:5 (weight ratio)), epoxy-based cross-linked 5 parts by weight of a linking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C"), 10 parts by weight of terpene phenol-based tackifying resin (manufactured by YASUHARA Chemicals, trade name "YS POLYSTER S145"), and 100 parts by weight of toluene Mixing was performed, and the composition for adhesive layer formation was prepared. The composition for forming an adhesive layer was coated on one surface of a polyethylene terephthalate film (manufactured by Toray Corporation, trade name "Lumirror S10", thickness 38 μm) as a substrate to obtain a substrate and an adhesive. Adhesive sheet composed of layers (thickness 10 μm). The obtained adhesive sheet was used for the above-mentioned evaluations (1) to (6). The results are shown in Table 1.

[Example 7] Acrylic copolymer C (copolymer of 2-ethylhexyl acrylate, ethyl acrylate, methyl methacrylate and hydroxyethyl acrylate, 2-ethylhexyl acrylate structural unit: ethyl acrylate structural unit: methyl acrylate) Methyl methacrylate structural unit: acrylic structural unit = 30:70:5:4 (weight ratio)) 100 parts by weight, thermally expandable microspheres (manufactured by Matsumoto Oil Pharmaceutical Co., Ltd., trade name "Matsumoto Microsphere F-190D") 30 weight parts parts, 1.4 parts by weight of an isocyanate-based crosslinking agent (manufactured by Tosoh Corporation, trade name "Coronate L"), 10 parts by weight of an adhesion imparting agent (manufactured by YASUHARA Chemicals, trade name "Mighty Ace G125"), and 100 parts by weight of toluene The composition for forming an adhesive layer was prepared by mixing, and the composition for forming an adhesive layer was coated on the opposite side of the polyethylene terephthalate film of the adhesive sheet of Example 3 to the side opposite to the adhesive layer. A second adhesive layer (thickness: 45 μm) was formed to obtain a double-sided adhesive sheet. The adhesive layer of the obtained double-sided adhesive sheet was used for the above-mentioned evaluations (1) to (6). The results are shown in Table 1.

[Comparative Example 1] 100 parts by weight of acrylic copolymer (copolymer of 2-ethylhexyl acrylate and acrylic acid, 2-ethylhexyl acrylate structural unit: acrylic structural unit=95:5 (weight ratio)), epoxy-based crosslinking 0.5 parts by weight of a chemical agent (Mitsubishi Gas Chemicals, trade name "Tetrad C"), 10 parts by weight of a terpene phenol-based tackifier resin (manufactured by YASUHARA Chemicals, trade name "YS POLYSTER S145"), and 100 parts by weight of toluene The mixture was mixed to prepare a composition for forming an adhesive layer. The composition for forming an adhesive layer was coated on one surface of a polyethylene terephthalate film (manufactured by Toray Corporation, trade name "Lumirror S10", thickness 38 μm) as a substrate to obtain a substrate and an adhesive. Adhesive sheet composed of layers (thickness 10 μm).

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Adhesive composition ingredient formulation amount (parts by weight) prepolymer Polymer A (2EHA/AA=95/5) 100 100 100 100 100 100 100 Polymer B (2EHA/HEA=100/4) 100 cross-linking agent Epoxy Crosslinker (Tetrad C) 3 5 5 10 5 5 0.5 Isocyanate based crosslinking agent (Coronate L) 3 adhesion imparting agent Rosinol-based adhesion imparting resin (SUMILITERESIN PR-12603) 10 10 10 10 10 Terpene phenolic tackifying resin (YS POLYSTER S145) 10 10 Evaluation Acid value (mgKOH/g) 9.5 3.7 3.8 0.12 0.01 3.6 3.8 16.6 Adhesion (N/20 mm) 0.68 0.12 0.23 0.11 0.84 0.22 0.22 7.24 Shear Adhesion @150℃(g) 1067 918 965 948 901 960 957 226 Shear Adhesion @190℃(g) 535 505 493 463 443 498 489 294 Shear Adhesion @150℃/Adhesion(g/(N/20 mm)) 1569 7650 4196 8618 1073 4364 4350 31 Gel fraction (%) 88.5 98 92.5 95 86.5 92 92.4 83 Nitrogen production 0.19 0.31 0.31 0.62 0.26 0.31 0.31 0.049 Paste Residue Evaluation ○ ◎ ◎ ◎ ○ ◎ ◎ ×

10: Substrate 20: Adhesive layer 30: Second adhesive layer 100,200: Adhesive sheet

FIG. 1 is a schematic cross-sectional view of an adhesive sheet according to an embodiment of the present invention. 2 is a schematic cross-sectional view of an adhesive sheet according to another embodiment of the present invention.

10: Substrate

20: Adhesive layer

100: Adhesive sheet

Claims (11)

An adhesive sheet comprising a base material and an adhesive layer disposed on at least one side of the base material, The adhesive layer contains an acrylic adhesive, The acrylic adhesive contains a base polymer with an acid value of 16 mgKOH/g or less. The adhesive sheet according to claim 1, comprising: the substrate, the adhesive layer disposed on one side of the substrate, and a second adhesive disposed on the side opposite to the adhesive layer of the substrate Floor. According to the adhesive sheet of claim 1 or 2, the shear adhesion force B at 150° C. when the above-mentioned adhesive layer is attached with a silicon wafer is relative to that when the above-mentioned adhesive layer is attached to polyethylene terephthalate. The ratio of the adhesive force A (shear adhesive force B/adhesion force A) at 23°C in the case of ester is 32.0 g/(N/20 mm) or more. The adhesive sheet according to any one of claims 1 to 3, wherein the above-mentioned base polymer is a cross-linked body of an acrylic polymer. The adhesive sheet according to any one of claims 1 to 4, wherein the gel fraction of the adhesive layer is 75% or more. The adhesive sheet of claim 4 or 5, wherein the above-mentioned acrylic adhesive comprises a crosslinking agent, The compounding quantity of this crosslinking agent is 0.08 mol equivalent - 2 mol equivalent with respect to the carboxyl group of the said acrylic polymer. The adhesive sheet according to claim 6, wherein the cross-linking agent is an epoxy-based cross-linking agent. The adhesive sheet according to any one of claims 1 to 7, wherein the amount of nitrogen gas generated when the adhesive layer is subjected to heat treatment is 0.05 wt % to 1.0 wt %. The adhesive sheet according to any one of claims 1 to 8, wherein the thickness of the adhesive layer is 1 μm to 300 μm. The adhesive sheet according to any one of claims 1 to 9, which is a temporary fixing material usable in a resin sealing step of a semiconductor wafer. The adhesive sheet according to claim 10 is used for curing the sealing resin on the above-mentioned adhesive sheet.

Images