TW201502234A - Adhesive sheet - Google Patents

Abstract

There is provided an adhesive sheet which has an extremely low concentration of total organic carbon during a cutting process and a washing process after the cutting, prevents chips in cutting process from scattering, ensures an easy pickup, and inhibits remaining past. According to the present invention, the adhesive sheet is formed by laminating an adhesive layer on a substrate. The adhesive layer is a photo-curable adhesive layer which contains 100 parts by mass of a (meth)acrylate ester copolymer, 5-200 parts by mass of a photopolymerizable compound,0.1-20 parts by mass of a multifunctional isocyanate curing agent, and 0.1-20 parts by mass of a photopolymerization initiator. The photopolymerizable compound has a weight average molecular weight of 500 or more. The adhesive sheet has been adjusted to a size of 50mmx50mm, and the concentration of total organic carbon eluted after being dipped in 500 ml of pure water for 24 hours is 5. mg/L or lower.

Description

Adhesive film

The present invention relates to an adhesive sheet used in the manufacture of electronic parts.

After bonding the adhesive sheet, the semiconductor wafer or the substrate is diced into a small piece of the element, an expansion of the adhesive sheet, and a pick up of the small piece of the self-adhesive sheet. The dicing tape used in these steps is desirably having sufficient adhesion to the component piece to be cut from the cutting step to the drying step, and the adhesive force can be reduced to the picking step. The extent to which the adhesive does not remain.

The adhesive sheet is an adhesive layer which is subjected to a polymerization hardening reaction by ultraviolet rays or the like on a substrate having transparency to active light such as ultraviolet rays and/or electron beams. This adhesive sheet is a method in which the adhesive layer is irradiated with ultraviolet rays or the like after the cutting step, the adhesive layer is polymerized and cured, and the adhesive force is lowered, and then the cut wafer is picked up.

As such an adhesive sheet, Patent Document 1 and Patent Document 2 disclose, for example, an adhesive comprising a compound (polyfunctional oligomer) containing a photopolymerizable unsaturated double bond in a molecule on a substrate surface. The adhesive is three-dimensionally reticulated by active light.

[Patent Document 1] JP-A-2006-049509 (Patent Document 2) JP-A-2007-246633

In the processing step of the semiconductor wafer or the substrate, a thin grinding wheel called a high-speed rotating blade is used in the cutting machine that performs the cutting step, and the workpiece is processed while sprinkling the polishing liquid and the cooling liquid.

In addition, it is extremely sensitive to the adhesion of the surface of the workpiece and the contamination in the grinding groove caused by the fine abrasive powder generated in the processing of the cutting machine, and therefore, a cleaning nozzle is provided in the vicinity of the rotating blade, thereby reducing The contaminant in the cutting is attached, and further, the workpiece after the cutting process is transported to the rotary cleaning device provided in the cutting machine, and the step of rotating the cleaning nozzle in the workpiece surface to perform the rotary cleaning while rotating the workpiece .

Pure water such as ultrapure water which has been highly removed, such as organic matter, ionic components, fine particles, and bacteria, is used in the cleaning liquid during and after the processing. In particular, when manufacturing an electronic component including a semiconductor device, a large amount of pure water is used in the above-described cleaning step, and the requirements for its water quality are increasing year by year. In order to prevent the problem that the organic matter contained in the pure water is carbonized in the subsequent heat treatment step and cause insulation failure, it is required to be one of the water quality management items in the pure water used for the cleaning step of the electronic component manufacturing. The concentration of organic carbon (TOC: Total Organic Carbon) must be at a very low level.

Therefore, the main object of the present invention is to provide an extremely low level of total organic carbon in the cleaning liquid during the cutting process and after the cutting process, and the wafer does not scatter during the cutting process, can be easily picked up, and is not easily produced. The adhesive sheet left by the adhesive.

The adhesive sheet of the present invention is an adhesive sheet formed by laminating an adhesive layer on a substrate, the adhesive layer is a photocurable adhesive layer, and the photocurable adhesive comprises 100 parts by mass of a (meth) acrylate copolymer. 5 to 200 parts by mass of the photopolymerizable compound, 0.1 to 20 parts by mass of the polyfunctional isocyanate curing agent, and 0.1 to 20 parts by mass of the photopolymerization initiator, and the weight average molecular weight of the photopolymerizable compound is 500 or more, and the adhesive sheet is adjusted. The concentration of total organic carbon (TOC: Total Organic Carbon) dissolved and precipitated in 500 mL of pure water for 24 hours after being immersed in a size of 50 mm × 50 mm was 5.0 mg/L or less.

Further, the pressure-sensitive adhesive sheet of the present invention is an adhesive sheet comprising an adhesive layer laminated on a substrate, and the pressure-sensitive adhesive layer contains a (meth) acrylate copolymer, a photopolymerizable compound, and a hardener as essential components, and the adhesive layer The concentration of total organic carbon (TOC: Total Organic Carbon) dissolved and dissolved in pure water is 3.0 mg/L or less, and the adhesive layer contains 100 parts by mass of a (meth) acrylate copolymer, and a polyfunctional isocyanate hardener 0.1. To 20 parts by mass and 0.1 to 20 parts by mass of the photopolymerization initiator, the (meth) acrylate copolymer and the photopolymerizable compound contain a hydroxyl group.

Further, a (meth) acrylate copolymer, a photopolymerizable compound, and a hardener are contained as essential components, and if there is no chemical bond between the (meth) acrylate copolymer and the hardener, and the photopolymerizable compound and the hardener When combined, the organic component of the adhesive layer becomes easily dissolved and precipitated into the water. As a result, the concentration of TOC contained in the cleaning liquid at the time of cutting becomes easy to rise, resulting in poor insulation of electronic parts and the like.

(Effect of the Invention) According to the present invention, it is provided that the total organic carbon concentration in the cleaning liquid during the cutting process and after the cutting process is extremely low, so that insulation defects are less likely to occur, and the wafer does not fly during the cutting process. Adhesive sheets that can be easily picked up and are not easily damaged by adhesives.

Hereinafter, preferred embodiments of the present invention will be described. In addition, the embodiment described below shows an example of a representative embodiment of the present invention, and the explanation of the scope of the present invention is not narrow.

<<First embodiment>>

The adhesive sheet of the present embodiment is an adhesive sheet formed by laminating an adhesive layer on a substrate, the adhesive layer is a photocurable adhesive layer, and the photocurable adhesive comprises a (meth) acrylate copolymer 100 mass. 5 parts by mass of the photopolymerizable compound, 0.1 to 20 parts by mass of the polyfunctional isocyanate curing agent, and 0.1 to 20 parts by mass of the photopolymerization initiator, and the weight average molecular weight of the photopolymerizable compound is 500 or more. The sheet was adjusted to have a size of 50 mm × 50 mm, and the concentration of total organic carbon (TOC: Total Organic Carbon) dissolved and precipitated in 500 mL of pure water for 24 hours was 5.0 mg/L or less.

Further, in order to form an adhesive sheet composed of an adhesive layer on a substrate, the adhesive sheet was adjusted to a size of 100 mm × 100 mm, and the concentration of total organic carbon (TOC: Total Organic Carbon) dissolved and precipitated after being immersed in water for 24 hours. It is 0 to 5 mg/L or less.

<Adhesive layer>

As the adhesive constituting the adhesive layer, there are acrylic acid, methacrylic acid, a polymer obtained by polymerizing the ester monomers, and unsaturated monomers which can be copolymerized with the monomers (for example, vinyl acetate, A copolymer of styrene and acrylonitrile. In the adhesive sheet of the present embodiment, the adhesive constituting the adhesive layer may be an acrylic polymer which is easy to design an adhesive force, and the adhesive force can be more precisely adjusted by containing a hardener. Further, at least one of the acrylic monomers constituting the acrylic polymer is preferably one containing a monomer having a functional group. It is preferred that the functional group-containing monomer is polymerized in an amount of 0.01% by mass or more and 10% by mass or less based on the acrylic polymer. When the ratio of the monomer having a functional group is 0.01% by mass or more, the adhesion to the object is sufficiently strong, and there is a tendency to suppress the generation of surrounding water, and if the monomer containing the functional group is incorporated When the ratio is 10% by mass or less, the adhesion to the object is not excessively high, and there is a tendency to suppress the generation of the paste residue.

The main monomer of the acrylic polymer may, for example, be butyl (meth)acrylate, 2-butyl (meth)acrylate, tert-butyl (meth)acrylate or amyl (meth)acrylate, ( Octyl methacrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, methyl (meth) acrylate , ethyl (meth)acrylate, isopropyl (meth)acrylate, tridecyl (meth)acrylate, myristyl (meth)acrylate, cetyl (meth)acrylate, (methyl) A (meth)acrylic monomer such as stearyl acrylate, cyclohexyl (meth) acrylate or benzyl (meth) acrylate.

It is particularly preferred that the acrylic monomer is at least partially a monomer having a functional group. The functional group-containing monomer is preferably a monomer having a hydroxyl group, a carboxyl group, an epoxy group, a decylamino group, an amine group, a methylol group, a sulfonic acid group, an aminosulfonic acid group or a (phosphite) group. . Further, among these, a vinyl compound having such a functional group may be particularly preferable, and among them, a vinyl compound having a hydroxyl group is preferred. Further, the vinyl compound therein also contains the acrylate described below.

The functional group-containing monomer having a hydroxyl group is, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate. The monomer having a carboxyl group may, for example, be (meth)acrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, acrylamide, N-glycolic acid, cinnamic acid or the like.

Examples of the monomer having an epoxy group include propenyl propyl triether ether and (meth)acrylic acid epoxy propyl ether.

Examples of the monomer having a guanamine group include (meth) acrylamide and the like.

Examples of the monomer having an amine group include acrylic acid-N,N-dimethylamine ethyl ester and the like.

Examples of the monomer having a methylol group include N-methylol acrylamide and the like.

Further, in the adhesive layer of the present embodiment, after the acrylic polymer and the curing agent are reacted to harden the adhesive layer, the carboxyl group-containing monomer of the acrylic polymer is formed to constitute 0.1 to 10 by mass of the acrylic polymer. % below is preferred. In other words, it is preferable that the functional group-containing monomer having a carboxyl group is contained in the functional group-containing monomer which reacts the adhesive with a curing agent in an amount of 10% by mass or less. By using a functional group-containing monomer having a carboxyl group, since the adhesion to the metal can be increased, if the functional group-containing monomer having a carboxyl group after reacting with the curing agent exceeds 10% by mass, the adhesion to the metal is high. Since the tendency of the paste residue is generated, it is preferably 10% by mass or less. Therefore, it is preferred that the monomer having a carboxyl group is easily removed as it reacts with the hardener, for example, using (meth)acrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, and fumar. Acid, acrylamide, N-glycolic acid and cinnamic acid are preferred.

(hardener)

In the adhesive sheet of the present embodiment, it is preferred to incorporate a curing agent into the adhesive used for the adhesive layer. When the curing agent is blended, the blending ratio of the curing agent is preferably 0.1 parts by mass or more and 10 parts by mass or less based on 100 parts by mass of the acrylic polymer. When the compounding ratio of the curing agent is 0.1 part by mass or more and 10 parts by mass or less, generation of a paste residue can be suppressed.

The hardener to be added to the adhesive layer may be a polyfunctional isocyanate hardener, a polyfunctional epoxy hardener, a nitrogen heterocyclic propylene compound, a melamine compound or the like, and a polyfunctional isocyanate hardener or a polyfunctional epoxy hardener is preferred. . By using a polyfunctional epoxy hardener or a polyfunctional isocyanate hardener as at least a part of the above-mentioned hardener, the functional group-containing monomer having a carboxyl group can be selectively reacted and disappeared, so that the functional group having a carboxyl group can be adjusted after hardening The amount of the base monomer.

Examples of the polyfunctional isocyanate curing agent include an aromatic polyisocyanate curing agent, an aliphatic polyisocyanate curing agent, and an alicyclic polyisocyanate curing agent. Further, an aliphatic polyisocyanate curing agent is preferred, and a hexamethylene diisocyanate curing agent is particularly preferred. The reason why the isocyanate curing agent is good is that it can impart flexibility to the adhesive, and is also effective for a body having irregularities.

The aromatic polyisocyanate is not particularly limited and may be, for example, 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-di Phenyl methane diisocyanate, 2,4-tolyl diisocyanate, 2,6-tolyl diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanatotoluene, 1 , 3,5-triisocyanatobenzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4',4"-triphenylmethane triisocyanate, ω,ω'- Diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanato-1,4-dimethylbenzene, ω,ω'-diisocyanato-1,4- Diethylbenzene, 1,4-tetramethylxylene diisocyanate, and 1,3-tetramethylxylene diisocyanate.

The aliphatic polyisocyanate is not particularly limited, and examples thereof include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, and 1,2-propyl group. Diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

The alicyclic polyisocyanate is not particularly limited, and examples thereof include 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, and 1,3-ring. Hexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylene double (cyclohexyl isocyanate), 1,4-bis(isocyanatomethyl)cyclohexane, and 1,4-bis(isocyanatomethyl)cyclohexane.

Among the polyisocyanates, 1,3-benzene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-toluene are preferably used. Diisocyanate, 2,6-toluene diisocyanate, 4,4'-toluidine diisocyanate, hexamethylene diisocyanate.

The polyfunctional epoxy hardener mainly means a compound having two or more epoxy groups and one or more tertiary nitrogen atoms, which may be N,N-glycidylaniline, N,N-glycidyltoluidine, or the like. -N,N-glycidylaminophenyl glycidyl ether, p-N,N-glycidylaminophenyl glycidyl ether, triglycidyl isocyanurate, N, N, N ',N'-tetraglycidyldiaminodiphenylmethane, N,N,N',N'-tetraglycidyl-m-xylylenediamine, N,N,N',N',N "-Furdose glycidyl di-ethyltriamine and the like.

The adhesive can be used as a pressure sensitive adhesive mainly comprising an acrylic polymer and a hardener, and can be used as a photocurable adhesive in addition to an acrylic polymer and a hardener, and the photocurable adhesive is photopolymerized. Compounds, photopolymerization initiators, tackifying resins, additives, and the like.

(photopolymerizable compound)

As the photopolymerizable compound, for example, trimethylolpropane triacrylate, neopentyltetraol tetraacrylate, pentaerythritol triacrylate, pentaerythritol triacrylate, dipentaerythritol monohydroxypentaacrylate, or the like can be used. Polydipentaerythritol hexaacrylate, 1,4-butanediol diacrylate, 1,6 hexanediol diacrylate, polyethylene glycol diacrylate, triethyl cyanate, commercially available low Polyester acrylate, etc.

As the photopolymerizable compound, a urethane acrylate oligomer can be used in addition to the above acrylate-based compound. a urethane acrylate oligomer having a hydroxyl group on a terminal isocyanate urethane prepolymer obtained by reacting a polyester compound and a polyether type compound with a polyvalent isocyanate compound; Methyl) acrylate derived.

Among the polyvalent isocyanate compounds, for example, 2,4-tolyl diisocyanate, 2,6-tolyl diisocyanate, 1,3-diisocyanate, 1,4-diisocyanate can be used. Xylene ester, 4,4-diphenylmethane diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and the like. Further, among the (meth) acrylate having a hydroxyl group, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, or polyethylene glycol (meth)acrylic acid can be used. Ester, pentaerythritol triacrylate, propylene glycol di(meth) acrylate, dipentaerythritol monohydroxy pentoxide, and the like.

The photopolymerizable compound is preferably a urethane acrylate oligomer having four or more vinyl groups, which is excellent in curing by an adhesive after irradiation with ultraviolet rays or the like.

The weight average molecular weight of the photopolymerizable compound is preferably 500 or more, more preferably 100 or more. When the weight average molecular weight of the photopolymerizable compound is too small, the concentration of TOC contained in the cleaning liquid at the time of dicing becomes easy to rise, resulting in poor insulation of electronic parts and the like.

The amount of the photopolymerizable compound is preferably 5 parts by mass or more and 200 parts by mass or less based on 100 parts by mass of the (meth) acrylate copolymer, and more preferably 40 parts by mass or more and 150 parts by mass or less. When the amount of the photopolymerizable compound is reduced, the peeling property of the adhesive sheet after the irradiation of the radiation is lowered, and the pickup failure of the semiconductor wafer is likely to occur. On the other hand, if the amount of the photopolymerizable compound is increased, picking up is likely to occur due to the sticking of the adhesive at the time of cutting, and contamination is caused by the occurrence of minute adhesive residue in the reaction residue.

(photopolymerization initiator)

As the photopolymerization initiator, benzoin, benzoin aralkyl ether, acetophenone, onion peptide, ketoxime, ketal, diphenylketone or xanthone can be used.

Examples of the benzoin include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin dipropyl ether and the like. Examples of the acetophenone system include benzoin aralkyl ether, acetophenone, 2,2-dimethoxy-2-acetophenone, 2,2-diethoxy-2-acetophenone, and 1, 1-Dichloroacetophenone and the like. Examples of the onion peptide system include 2-methyloxime, 2-ethylhydrazine, 2-tert-butylhydrazine, 1-chloroindole and the like. Examples of the ketoxime system include 2,4-dimethyl ketoxime, 2,4-diisopropyl ketoxime, 2-chloroseptone, 2,4-diisopropyl ketoxime, and the like. . Examples of the ketal system include acetophenone dimethyl ketal, benzyl dimethyl ketal, benzyl diphenyl sulphide, tetramethyl thiuram monosulfide, azobisisobutyronitrile, and Phenyl, diacetyl, β-chloropurine and the like. Among them, in order to prevent contamination by the body, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propenyl)-benzoic acid having a hydroxyl group obtained by reacting with an isocyanate hardener Peptidyl]-2-phenyl-propan-1-one (manufactured by BASF JAPAN, product name IRGACURE 127) is preferred.

The amount of the photopolymerization initiator to be used is preferably 0.1 part by mass or more and 20 parts by mass or less based on 100 parts by mass of the (meth) acrylate polymer. When the amount of the mixture is too small, the peeling property of the adhesive sheet after irradiation with radiation is lowered, and the pickup failure of the semiconductor wafer is likely to occur. On the other hand, if the amount of the mixture is too large, the photopolymerization initiator flows to the surface of the adhesive to cause contamination.

In the photopolymerization initiator, one or two kinds of previously known photopolymerization accelerators may be used in combination as needed. Among the photopolymerization accelerators, benzoic acid-based compounds and tertiary amines can be used. Examples of the tertiary amine include triethylamine, tetraethylenepentamine, dimethylamine ether and the like.

(tackifying resin)

As the tackifier resin, it is a terpene phenol resin in which a terpene phenol resin is completely or partially hydrogenated.

For example, terpene 1 mole can be reacted with a phenol type of 0.1 to 50 to produce a terpene phenol resin.

Examples of the terpene compound include myrcene, allo-ocimene, basilene, α-pinene, β-pinene, dipentene, decene, α-phellandrene, α-terpinene, and γ-terpinene. , terpinolene, 1,8-cineole, 1,4-cineole, alpha-terpineol, beta-terpineol, gamma-terpineol, terpene, tricycloolefin, terpene, pentahydrate Diene, terpene, and the like. Among these compounds, α-pinene, β-pinene, decene, myrcene, allo-ocimene, and α-terpinene are particularly preferably used in the present invention.

Examples of the phenol type include phenol, cresol, xylenol, catechol, resorcin, hydroquinone, and bisphenol A, but are not limited thereto.

The phenolic ratio of the terpene phenol resin is about 25 to 50 mol%, but is not limited thereto.

The completely or partially hydrogenated terpene phenol resin preferably has a hydroxyl value of from 50 to 250. When the hydroxyl value is less than 50, the reaction with the isocyanate-based hardener is insufficient, and it may bleed out to the surface of the adhesive to cause contamination; when the hydroxyl value is higher than 250, the viscosity will rise, resulting in copolymerization with (meth) acrylate. The mixing of the objects and the like is uneven, resulting in unstable pickup characteristics.

The method of hydrogenation is not particularly limited, and examples thereof include a noble metal such as palladium, rhodium or ruthenium, or a method of using these as a catalyst on a carrier such as activated carbon, activated alumina or diatomaceous earth. The hydrogenation rate can be measured by means of bromine number measurement, iodine value measurement or the like.

The hydrogenation ratio of the fully or partially hydrogenated terpene phenol resin is preferably 30 mol% or more, and more preferably 70 mol% or more. When the amount is less than 30% by mole, the reaction of the photopolymerizable compound irradiated with the active light is inhibited, and the adhesive force cannot be sufficiently lowered, so that the pickup property is lowered.

The mixing ratio of the completely or partially hydrogenated terpene phenol resin is preferably 0.5 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of the (meth) acrylate copolymer, and is preferably 1.0 part by mass or more and 50 parts by mass. The following are better. When the total or partial hydrogenated terpene phenol resin is 0.5 parts by mass or more, the adhesion is not excessively lowered, and the retention of the semiconductor wafer at the time of dicing can be maintained. When the amount is 100 parts by mass or less, the occurrence of pickup failure can be suppressed.

(additive)

Various additives such as a softener, an anti-aging agent, a filler, a conductive agent, an ultraviolet absorber, and a light stabilizer may be added to the adhesive.

The thickness of the adhesive layer is preferably 1 μm or more and 50 μm or less, and more preferably 5 μm or more and 35 μm or less. If the adhesive layer is too thick, the adhesive force becomes too high and the pickup property is lowered. Further, when the adhesive layer is too thin, the adhesive force is too low, and the wafer retainability at the time of dicing is lowered, and peeling may occur between the annular frame and the sheet.

<Substrate>

As the material of the substrate, there are, for example, polyvinyl chloride, polyethylene terephthalate, ethylene-vinyl acetate copolymer, ethylene-acrylic acid-acrylate film, ethylene-ethyl acrylate copolymer, polyethylene, polypropylene, An ethylene-acrylic acid copolymer, and an ionomer resin obtained by crosslinking a polymer such as an ethylene-(meth)acrylic copolymer and an ethylene-(meth)acrylic acid-(meth)acrylate copolymer by metal ions Wait. The substrate may be a mixture or copolymer of these resins, or a laminate of films or sheets which may be composed of these resins.

The material of the substrate film is preferably an ionomer resin. In the ionomer resin, an ionomer obtained by crosslinking a copolymer of an ethylene unit, a methacrylic acid unit, and an alkyl (meth) acrylate unit with a metal ion such as Na ⁺ , K ⁺ , or Zn ²⁺ The resin has a remarkable effect of suppressing chips, and therefore is preferably used.

The substrate may be a single layer or a multilayer film or sheet composed of the above materials, or may be formed of a film or the like which is formed by laminating different materials. The thickness of the substrate is 50 to 200 μm, preferably 70 to 150 μm.

For the substrate, it is preferred to carry out an antistatic treatment. As the antistatic treatment, there are a treatment of adding an antistatic agent to a substrate, a treatment of applying an antistatic agent to the surface of the substrate, and a treatment by corona discharge.

As the antistatic agent, for example, a quaternary amine salt monomer or the like can be used. Examples of the quaternary amine salt monomer include dimethylaminoethyl (meth)acrylate tetrachloride, diethylamine ethyl (meth)acrylate tetrachloride, and methyl ethylamine ethyl (meth)acrylate. Tetrachloride, p-dimethylamine styrene tetrachloride and p-diethylamine styrene tetrachloride. Among them, dimethylamine (meth) acrylate tetrachloride is preferred.

The method of using the lubricant and the antistatic agent is not particularly limited. For example, an adhesive may be applied to one side of the substrate film, and a lubricant and/or an antistatic agent may be applied to the back side, and the lubricant and/or the lubricant may be used. The antistatic agent is kneaded into the resin of the base film to form a film.

An adhesive may be laminated on one side of the substrate, and an embossed surface having an average surface roughness (Ra) of 0.3 to 1.5 μm may be formed on the other surface. By providing the embossed surface on the mechanical table side of the expansion device, the substrate can be easily expanded in the expansion process after cutting.

In order to improve the expandability after cutting, a lubricant may be applied to the non-contact surface of the adhesive of the base film, or the lubricant may be kneaded into the base film.

(lubricant)

The lubricant is not particularly limited as long as it can reduce the friction coefficient of the adhesive sheet and the expansion device, and examples thereof include organic bismuth resins such as organic oxime resins or (modified) organic eucalyptus oils, fluorine-containing resins, and hexagonal boron nitride. , carbon black and molybdenum disulfide. These friction reducing agents can be made by mixing a plurality of ingredients. Since the manufacture of electronic parts is carried out in a clean room, it is preferred to use an organic ruthenium compound or a fluorine-containing resin. Among the organic ruthenium compounds, since the copolymer having an organic oxime macromonomer unit has good compatibility with an antistatic layer and can achieve both antistatic property and expandability, it can be preferably used.

<Manufacturing process of electronic parts>

Specific steps of the method of manufacturing the electronic component of the present invention will be described in order.

(1) Bonding step: First, in the bonding step, the adhesive sheet is attached to the semiconductor wafer (or substrate) and the annular frame. The wafer can be a conventional wafer such as a germanium wafer and a gallium nitride wafer, a silicon carbide wafer, or a sapphire wafer. The substrate may be a general-purpose substrate such as a package substrate in which a wafer is sealed with a resin, an LED package substrate, or the like.

(2) Cutting step: In the cutting step, a germanium wafer or the like is cut to form a semiconductor wafer or a semiconductor component.

(3) Light irradiation step: In the light irradiation step, active light rays such as ultraviolet rays are irradiated from the substrate side to the photo-curable adhesive layer. As a light source of ultraviolet rays, a low pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, or a metal halide lamp can be used. Alternatively, an electron beam can be used instead of ultraviolet light. As the light source of the electron beam, an α line, a β line, or a γ line can be used.

The adhesive layer is hardened by three-dimensional reticulation by light irradiation, and the adhesion of the adhesive layer is lowered. At this time, as described above, the adhesive sheet of the present invention does not excessively adhere to the wafer or the like even when heated, so that the adhesion can be sufficiently reduced by irradiation with ultraviolet rays or the like.

(4) Expansion/pickup step: In the expansion/pickup step, the adhesive sheet is stretched to enlarge the distance between the semiconductor wafer and the semiconductor component, and the wafer or the component is lifted up by a ejector pin or the like. Next, the wafer or the part is adsorbed by a vacuum collet or a pneumatic tweezers, and the adhesive layer of the adhesive sheet is peeled off and picked up. In this case, since the adhesive sheet of the present invention can be sufficiently reduced in adhesion by irradiation with ultraviolet rays or the like, peeling between the wafer or the component and the adhesive layer is facilitated, and good pickup property can be obtained without Adverse conditions such as adhesive residue.

<Manufacture of adhesive sheets>

As a method of forming an adhesive layer on a substrate, for example, a coating machine such as a concave coater, a notch coater, a bar coater, a knife coater or a roll coater is used to directly apply an adhesive. A method of coating on a substrate, or a method of applying an adhesive to a release film, drying it, and bonding it to a substrate film. The adhesive can also be printed onto the substrate by letterpress, gravure, lithographic, flexographic, plano-convex or screen printing.

The adhesive sheet of the present invention is suitably used for the attachment of an electronic component assembly called a workpiece in the manufacturing process of the electronic component, that is, the cutting step and the back grinding step.

The adhesive composition and the adhesive sheet in the examples and the comparative examples were produced in accordance with the following formulations. The main formulations and the results of the respective experimental examples are shown in Tables 1 to 2.

The hardening type adhesive was applied onto a separator film made of polyethylene terephthalate, and the thickness of the adhesive layer after drying was 20 μm. The adhesive layer was laminated on a base film, and aged at 40 ° C for 7 days to obtain an adhesive sheet. In the base film, a Zn salt of an ethylene-methacrylic acid-alkyl methacrylate copolymer, which is an ionomer resin, is mainly used, and MFR 値 1.0 g/10 minutes (JIS K7210, 210 ° C), melting point 86 °C, containing Zn ²⁺ ions (manufactured by Mitsui DuPont Chemical Co., Ltd., part number: HM1855), which was extruded with a T die to form a 100 μm film.

[Photohardenable Adhesive]

[(Meth)acrylate copolymer]

A-1: Acrylic rubber AR53L manufactured by Zeon Co., Ltd.; can be obtained by emulsion polymerization of a copolymer of 54% ethyl acrylate, 19% butyl acrylate, and 24% methoxyethyl acrylate.

A-2: SK-Dyne 1496 manufactured by Soken Chemical Co., Ltd.; can be obtained by solution polymerization of a copolymer of 2-ethylhexyl acrylate 96% and 2-hydroxyethyl acrylate 4%.

[Photopolymerizable compound]

A terminal isocyanate compound obtained by reacting an OH terminal of pentaerythritol with hexamethylene diisocyanate, and further reacting with 2-hydroxyethyl acrylate to form an urethane acrylate oligomer (synthesis product) having 4 vinyl groups per molecule. . Further, the number average molecular weight is a value measured by gel permeation chromatography (GPC) in such a manner as to convert the number average molecular weight of polystyrene. B-1: weight average molecular weight 300 B-2: weight average molecular weight 500 B-3: weight average molecular weight 1,300 B-4: weight average molecular weight 4,100 B-5: weight average molecular weight 120,000 B-6: weight average molecular weight 230,000

[Polyfunctional isocyanate curing agent] C-1: CORONATE L-45E manufactured by Nippon Polyurethane Industry Co., Ltd.; trimethylolpropane adduct of 2,4-tolyl diisocyanate. C-2: CORONATE HL manufactured by Nippon Polyurethane Industry Co., Ltd.; trimethylolpropane adduct of hexamethylene diisocyanate.

[Photopolymerization initiator] D-1: IRGACURE127 manufactured by BASF JAPAN Co., Ltd.; 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propenyl)-benzyl]-benzene }}-2-methyl-propan-1-one. D-2: IRGACURE 651 manufactured by BASF JAPAN; diphenylmethyl ketal.

(1) Method for determining TOC concentration

The obtained adhesive sheet was adjusted in the following procedure, and the sample was measured by a total organic carbon meter (ON-LINE TOC-VCHS manufactured by Shimadzu Corporation) in accordance with the "combustion oxidation-infrared TOC analysis method" of JIS K 0101 20.1. TOC concentration. 1. Cut the adhesive sheet into 50 mm × 50 mm. 2. 500 Ml of pure water having a TOC concentration of 5 ppb or less was placed in a sampling bottle which had been thoroughly washed with pure water, and the adhesive sheet of the peeled separator film was shaken in pure water for 30 seconds. 3. Dip the adhesive sheet down in pure water. 4. Let stand at 23 °C. 5. Remove the adhesive after 24 hours. 6. The TOC concentration of the solution was measured three times, and the average value was taken as the measured value.

The TOC concentration obtained by the above method was evaluated by the following criteria. ◎ (excellent): 0 to 2.0 mg / L ○ (good): 2.1 to 5.0 mg / L × (bad): more than 5.0 mg / L

(2) Evaluation of wafer retention and pick-up

The obtained adhesive sheet was bonded to a tantalum wafer having a diameter of 8 inches × 0.1 mm and a ring frame forming a virtual circuit pattern. Next, it was heated at 75 ° C for 30 minutes using an oven during heating. After that, each step of cutting and picking is performed.

The conditions of the cutting step are as follows. Cutting device: DAD341 manufactured by DISCO Cutting board: NBC-ZH205O-27HEEE manufactured by DISCO. Cutting board shape: outer diameter 55.56mm, tooth width 35μm, inner diameter 19.05mm. Cutting plate rotation speed: 40,000 rpm Cutting plate Feeding speed: 50 mm/sec Cutting size: 1.5 mm angle Cutting depth for adhesive sheet: 15 μm Cutting water temperature: 25°C Cutting water volume: 1.0 liter/min

The conditions for the pickup step are as follows. Pickup device: CAP-300II made by Canon-Machinery Co., Ltd. Expansion amount: 8mm Thimble shape: 70μmR Number of thimbles: 1 thimble jacking height: 0.5mm

In the cutting step and the picking step, the following evaluations were made.

(2-1) Wafer retention:

For wafer retention, after the dicing step, the residual rate of the semiconductor wafer fixed on the adhesive sheet by the semiconductor wafer was evaluated by the following criteria. ◎(Excellent): The wafer scatters less than 5% ○(good): The wafer scatters more than 5% and is less than 10% × (bad): the wafer scatters more than 10%

(2-2) Pickup

For the pickup property, in the pickup step, the transfer success rate (pickup success rate) of the transfer of the semiconductor wafer using the transfer adhesive sheet was evaluated by the following criteria. ◎(Excellent): The pick-up success rate of the wafer is over 95%. ○(Good): The pick-up success rate of the wafer is 80% or more and less than 95% × (bad): the chip pick-up success rate is less than 80%

<<Second embodiment>>

The adhesive sheet of the present embodiment is an adhesive sheet formed by laminating an adhesive layer on a substrate, and the adhesive layer contains a (meth) acrylate copolymer, a photopolymerizable compound, and a hardener as essential components, and the adhesive The concentration of total organic carbon (TOC: Total Organic Carbon) dissolved and dissolved in pure water is 3.0 mg/L or less, and the adhesive layer contains 100 parts by mass of a (meth) acrylate copolymer and a polyfunctional isocyanate curing agent 0.1 to 0.1. 20 parts by mass and 0.1 to 20 parts by mass of the photopolymerization initiator, the (meth) acrylate copolymer and the photopolymerizable compound contain a hydroxyl group.

<Adhesive layer>

As the adhesive constituting the adhesive layer, there are acrylic acid, methacrylic acid, a polymer obtained by polymerizing the ester monomers, and unsaturated monomers which can be copolymerized with the monomers (for example, vinyl acetate, A copolymer of styrene and acrylonitrile. In the adhesive sheet of the present embodiment, the adhesive constituting the adhesive layer may be an acrylic polymer which is easy to design an adhesive force, and the adhesive force can be more precisely adjusted by containing a hardener. Further, at least one of the acrylic monomers constituting the acrylic polymer is preferably one containing a monomer having a functional group. It is preferred that the functional group-containing monomer is polymerized in an amount of 0.01% by mass or more and 10% by mass or less based on the acrylic polymer. When the ratio of the monomer having a functional group is 0.01% by mass or more, the adhesion to the object is sufficiently strong, and there is a tendency to suppress the generation of surrounding water, and if the monomer containing the functional group is incorporated When the ratio is 10% by mass or less, the adhesion to the object is not excessively high, and there is a tendency to suppress the generation of the paste residue.

The main monomer of the acrylic polymer may, for example, be butyl (meth)acrylate, 2-butyl (meth)acrylate, tert-butyl (meth)acrylate or amyl (meth)acrylate, ( Octyl methacrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, methyl (meth) acrylate , ethyl (meth)acrylate, isopropyl (meth)acrylate, tridecyl (meth)acrylate, myristyl (meth)acrylate, cetyl (meth)acrylate, (methyl) A (meth)acrylic monomer such as stearyl acrylate, cyclohexyl (meth) acrylate or benzyl (meth) acrylate.

It is particularly preferred that the acrylic monomer is at least partially a monomer having a functional group. The functional group-containing monomer is preferably a monomer having a hydroxyl group, a carboxyl group, an epoxy group, a decylamino group, an amine group, a methylol group, a sulfonic acid group, an aminosulfonic acid group or a (phosphite) group. . Further, among these, a vinyl compound having such a functional group may be particularly preferable, and among them, a vinyl compound having a hydroxyl group is preferred. Further, the vinyl compound therein also contains the acrylate described below.

The functional group-containing monomer having a hydroxyl group is, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate.

The monomer having a carboxyl group may, for example, be (meth)acrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, acrylamide, N-glycolic acid, cinnamic acid or the like.

Examples of the monomer having an epoxy group include propenyl propyl triether ether and (meth)acrylic acid epoxy propyl ether.

Examples of the monomer having a guanamine group include (meth) acrylamide and the like.

Examples of the monomer having an amine group include acrylic acid-N,N-dimethylamine ethyl ester and the like.

Examples of the monomer having a methylol group include N-methylol acrylamide and the like.

Further, in the adhesive layer of the present embodiment, after the acrylic polymer and the curing agent are reacted to harden the adhesive layer, the carboxyl group-containing monomer of the acrylic polymer is formed to constitute 0.1 to 10 by mass of the acrylic polymer. % below is preferred. In other words, it is preferable that the functional group-containing monomer having a carboxyl group is contained in the functional group-containing monomer which reacts the adhesive with a curing agent in an amount of 10% by mass or less. By using a functional group-containing monomer having a carboxyl group, since the adhesion to the metal can be increased, if the functional group-containing monomer having a carboxyl group after reacting with the curing agent exceeds 10% by mass, the adhesion to the metal is high. Since the tendency of the paste residue is generated, it is preferably 10% by mass or less. Therefore, it is preferred that the monomer having a carboxyl group is easily removed as it reacts with the hardener, for example, using (meth)acrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, and fumar. Acid, acrylamide, N-glycolic acid and cinnamic acid are preferred.

(hardener)

In the adhesive sheet of the present embodiment, it is preferred to incorporate a curing agent into the adhesive used for the adhesive layer. When the curing agent is blended, the blending ratio of the curing agent is preferably 0.1 part by mass or more and 20 parts by mass or less based on 100 parts by mass of the acrylic polymer. When the ratio of the curing agent is 0.1 parts by mass or more and 15 parts by mass or less, generation of a paste residue can be suppressed.

The hardener to be added to the adhesive layer may be a polyfunctional isocyanate hardener, a polyfunctional epoxy hardener, a nitrogen heterocyclic propylene compound, a melamine compound or the like, and a polyfunctional isocyanate hardener or a polyfunctional epoxy hardener is preferred. . By using a polyfunctional epoxy hardener or a polyfunctional isocyanate hardener as at least a part of the above-mentioned hardener, the functional group-containing monomer having a carboxyl group can be selectively reacted and disappeared, so that the functional group having a carboxyl group can be adjusted after hardening The amount of the base monomer.

Examples of the polyfunctional isocyanate curing agent include an aromatic polyisocyanate curing agent, an aliphatic polyisocyanate curing agent, and an alicyclic polyisocyanate curing agent. Further, an aliphatic polyisocyanate curing agent is preferred, and a hexamethylene diisocyanate curing agent is particularly preferred. The reason why the isocyanate curing agent is good is that it can impart flexibility to the adhesive, and is also effective for a body having irregularities.

The aromatic polyisocyanate is not particularly limited and may be, for example, 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-di Phenyl methane diisocyanate, 2,4-tolyl diisocyanate, 2,6-tolyl diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanatotoluene, 1 , 3,5-triisocyanatobenzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4',4"-triphenylmethane triisocyanate, ω,ω'- Diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanato-1,4-dimethylbenzene, ω,ω'-diisocyanato-1,4- Diethylbenzene, 1,4-tetramethylxylene diisocyanate, and 1,3-tetramethylxylene diisocyanate.

The aliphatic polyisocyanate is not particularly limited, and examples thereof include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, and 1,2-propyl group. Diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

The alicyclic polyisocyanate is not particularly limited, and examples thereof include 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, and 1,3-ring. Hexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylene double (cyclohexyl isocyanate), 1,4-bis(isocyanatomethyl)cyclohexane, and 1,4-bis(isocyanatomethyl)cyclohexane.

Among the polyisocyanates, 1,3-benzene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-toluene are preferably used. Diisocyanate, 2,6-toluene diisocyanate, 4,4'-toluidine diisocyanate, hexamethylene diisocyanate.

The polyfunctional epoxy hardener mainly means a compound having two or more epoxy groups and one or more tertiary nitrogen atoms, which may be N,N-glycidylaniline, N,N-glycidyltoluidine, or the like. -N,N-glycidylaminophenyl glycidyl ether, p-N,N-glycidylaminophenyl glycidyl ether, triglycidyl isocyanurate, N, N, N ',N'-tetraglycidyldiaminodiphenylmethane, N,N,N',N'-tetraglycidyl-m-xylylenediamine, N,N,N',N',N "-Furdose glycidyl di-ethyltriamine and the like.

The adhesive can be used as a pressure sensitive adhesive mainly comprising an acrylic polymer and a hardener, and can be used as a photocurable adhesive in addition to an acrylic polymer and a hardener, and the photocurable adhesive is photopolymerized. Compounds, photopolymerization initiators, tackifying resins, additives, and the like.

(photopolymerizable compound)

As the photopolymerizable compound, a hydroxyl group is preferred. As the photopolymerizable compound containing a hydroxyl group, for example, pentaerythritol triacrylate, dipentaerythritol monohydroxypentaacrylate, or the like is used.

As the photopolymerizable compound, an epoxy acrylate oligomer such as a bisphenol A epoxy acrylate represented by the following formula may be used in addition to the acrylate compound.

(1)

(In the chemical formula, R represents a hydrogen molecule or a (meth) acrylate group. n represents an integer of 1 or more.)

The photopolymerizable compound preferably has four or more vinyl groups, and is excellent in curing by an adhesive after irradiation with ultraviolet rays or the like.

The amount of the photopolymerizable compound is preferably 5 parts by mass or more and 200 parts by mass or less, and more preferably 20 parts by mass or more and 120 parts by mass or less, based on 100 parts by mass of the (meth) acrylate copolymer. When the amount of the photopolymerizable compound is reduced, the peeling property of the adhesive sheet after the irradiation of the radiation is lowered, and the pickup failure of the semiconductor wafer is likely to occur. On the other hand, if the amount of the photopolymerizable compound is increased, picking up is likely to occur due to the sticking of the adhesive at the time of cutting, and contamination is caused by the occurrence of minute adhesive residue in the reaction residue.

(photopolymerization initiator)

As the photopolymerization initiator, benzoin, benzoin aralkyl ether, acetophenone, onion peptide, ketoxime, ketal, diphenylketone or xanthone can be used.

Examples of the benzoin include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin dipropyl ether and the like.

Examples of the acetophenone system include benzoin aralkyl ether, acetophenone, 2,2-dimethoxy-2-acetophenone, 2,2-diethoxy-2-acetophenone, and 1, 1-Dichloroacetophenone and the like.

Examples of the onion peptide system include 2-methyloxime, 2-ethylhydrazine, 2-tert-butylhydrazine, 1-chloroindole and the like.

Examples of the ketoxime system include 2,4-dimethyl ketoxime, 2,4-diisopropyl ketoxime, 2-chloroseptone, 2,4-diisopropyl ketoxime, and the like. .

Examples of the ketal system include acetophenone dimethyl ketal, benzyl dimethyl ketal, benzyl diphenyl sulphide, tetramethyl thiuram monosulfide, azobisisobutyronitrile, and Phenyl, diacetyl, β-chloropurine and the like.

Among them, in order to prevent contamination by the body, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propenyl)-benzoic acid having a hydroxyl group obtained by reacting with an isocyanate hardener Peptidyl]-2-phenyl-propan-1-one (manufactured by BASF JAPAN, product name IRGACURE 127) is preferred.

The amount of the photopolymerization initiator to be used is preferably 0.1 part by mass or more and 20 parts by mass or less based on 100 parts by mass of the (meth) acrylate polymer. When the amount of the mixture is too small, the peeling property of the adhesive sheet after irradiation with radiation is lowered, and the pickup failure of the semiconductor wafer is likely to occur. On the other hand, if the amount of the mixture is too large, the photopolymerization initiator flows to the surface of the adhesive to cause contamination.

In the photopolymerization initiator, one or two kinds of previously known photopolymerization accelerators may be used in combination as needed. Among the photopolymerization accelerators, benzoic acid-based compounds and tertiary amines can be used. Examples of the tertiary amine include triethylamine, tetraethylenepentamine, dimethylamine ether and the like.

(tackifying resin)

As the tackifier resin, it is a terpene phenol resin in which a terpene phenol resin is completely or partially hydrogenated.

For example, terpene 1 mole can be reacted with a phenol type of 0.1 to 50 to produce a terpene phenol resin.

Examples of the terpene compound include myrcene, allo-ocimene, basilene, α-pinene, β-pinene, dipentene, decene, α-phellandrene, α-terpinene, and γ-terpinene. , terpinolene, 1,8-cineole, 1,4-cineole, alpha-terpineol, beta-terpineol, gamma-terpineol, terpene, tricycloolefin, terpene, pentahydrate Diene, terpene, and the like. Among these compounds, α-pinene, β-pinene, decene, myrcene, allo-ocimene, and α-terpinene are particularly preferably used in the present invention.

Examples of the phenol type include phenol, cresol, xylenol, catechol, resorcin, hydroquinone, and bisphenol A, but are not limited thereto.

The phenolic ratio of the terpene phenol resin is about 25 to 50 mol%, but is not limited thereto.

The completely or partially hydrogenated terpene phenol resin preferably has a hydroxyl value of from 50 to 250. When the hydroxyl value is less than 50, the reaction with the isocyanate-based hardener is insufficient, and it may bleed out to the surface of the adhesive to cause contamination; when the hydroxyl value is higher than 250, the viscosity will rise, resulting in copolymerization with (meth) acrylate. The mixing of the objects and the like is uneven, resulting in unstable pickup characteristics.

The method of hydrogenation is not particularly limited, and examples thereof include a noble metal such as palladium, rhodium or ruthenium, or a method of using these as a catalyst on a carrier such as activated carbon, activated alumina or diatomaceous earth. The hydrogenation rate can be measured by means of bromine number measurement, iodine value measurement or the like.

The hydrogenation ratio of the fully or partially hydrogenated terpene phenol resin is preferably 30 mol% or more, and more preferably 70 mol% or more. When the amount is less than 30% by mole, the reaction of the photopolymerizable compound irradiated with the active light is inhibited, and the adhesive force cannot be sufficiently lowered, so that the pickup property is lowered.

The mixing ratio of the completely or partially hydrogenated terpene phenol resin is preferably 0.5 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of the (meth) acrylate copolymer, and is preferably 1.0 part by mass or more and 50 parts by mass. The following are better. When the total or partial hydrogenated terpene phenol resin is 0.5 parts by mass or more, the adhesion is not excessively lowered, and the retention of the semiconductor wafer at the time of dicing can be maintained. When the amount is 100 parts by mass or less, the occurrence of pickup failure can be suppressed.

(additive)

Various additives such as a softener, an anti-aging agent, a filler, a conductive agent, an ultraviolet absorber, and a light stabilizer may be added to the adhesive.

The thickness of the adhesive layer is preferably 1 μm or more and 50 μm or less, and more preferably 5 μm or more and 35 μm or less. If the adhesive layer is too thick, the adhesive force becomes too high and the pickup property is lowered. Further, when the adhesive layer is too thin, the adhesive force is too low, and the wafer retainability at the time of dicing is lowered, and peeling may occur between the annular frame and the sheet.

<Substrate>

As the material of the substrate, there are, for example, polyvinyl chloride, polyethylene terephthalate, ethylene-vinyl acetate copolymer, ethylene-acrylic acid-acrylate film, ethylene-ethyl acrylate copolymer, polyethylene, polypropylene, An ethylene-acrylic acid copolymer, and an ionomer resin obtained by crosslinking a polymer such as an ethylene-(meth)acrylic copolymer and an ethylene-(meth)acrylic acid-(meth)acrylate copolymer by metal ions Wait. The substrate may be a mixture or copolymer of these resins, or a laminate of films or sheets which may be composed of these resins.

The material of the substrate film is preferably an ionomer resin. In the ionomer resin, an ionomer obtained by crosslinking a copolymer of an ethylene unit, a methacrylic acid unit, and an alkyl (meth) acrylate unit with a metal ion such as Na ⁺ , K ⁺ , or Zn ²⁺ The resin has a remarkable effect of suppressing chips, and therefore is preferably used.

The substrate may be a single layer or a multilayer film or sheet composed of the above materials, or may be formed of a film or the like which is formed by laminating different materials. The thickness of the substrate is 50 to 200 μm, preferably 70 to 150 μm.

For the substrate, it is preferred to carry out static electricity prevention treatment. As the static electricity prevention treatment, there is a treatment of adding an antistatic agent to the substrate, a treatment of applying an antistatic agent to the surface of the substrate, and a treatment by corona discharge.

As the antistatic agent, for example, a quaternary amine salt monomer or the like can be used. Examples of the quaternary amine salt monomer include dimethylaminoethyl (meth)acrylate tetrachloride, diethylamine ethyl (meth)acrylate tetrachloride, and methyl ethylamine ethyl (meth)acrylate. Tetrachloride, p-dimethylamine styrene tetrachloride and p-diethylamine styrene tetrachloride. Among them, dimethylamine (meth) acrylate tetrachloride is preferred.

The method of using the lubricant and the antistatic agent is not particularly limited. For example, an adhesive may be applied to one side of the substrate film, and a lubricant and/or an antistatic agent may be applied to the back side, and the lubricant and/or the lubricant may be used. The antistatic agent is kneaded into the resin of the base film to form a film.

An adhesive may be laminated on one side of the substrate, and an embossed surface having an average surface roughness (Ra) of 0.3 to 1.5 μm may be formed on the other surface. By providing the embossed surface on the mechanical table side of the expansion device, the substrate can be easily expanded in the expansion process after cutting.

In order to improve the expandability after cutting, a lubricant may be applied to the non-contact surface of the adhesive of the base film, or the lubricant may be kneaded into the base film.

(lubricant)

The lubricant is not particularly limited as long as it can reduce the friction coefficient of the adhesive sheet and the expansion device, and examples thereof include organic bismuth resins such as organic oxime resins or (modified) organic eucalyptus oils, fluorine-containing resins, and hexagonal boron nitride. , carbon black and molybdenum disulfide. These friction reducing agents can be made by mixing a plurality of ingredients. Since the manufacture of electronic parts is carried out in a clean room, it is preferred to use an organic ruthenium compound or a fluorine-containing resin. Among the organic ruthenium compounds, since the copolymer having an organic oxime macromonomer unit has good compatibility with an antistatic layer and can achieve both antistatic property and expandability, it can be preferably used.

<Manufacturing process of electronic parts>

Specific steps of the method of manufacturing the electronic component of the present invention will be described in order.

(1) Lamination step

First, in the bonding step, the adhesive sheet is attached to the semiconductor wafer (or substrate) and the annular frame. The wafer can be a conventional wafer such as a germanium wafer and a gallium nitride wafer, a silicon carbide wafer, or a sapphire wafer. The substrate may be a general-purpose substrate such as a package substrate in which a wafer is sealed with a resin, an LED package substrate, or the like.

(2) Cutting step

In the dicing step, a germanium wafer or the like is diced to form a semiconductor wafer or a semiconductor component.

(3) Light irradiation step

In the light irradiation step, the photocurable adhesive layer is irradiated with active light such as ultraviolet rays from the substrate side. As a light source of ultraviolet rays, a low pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, or a metal halide lamp can be used. Alternatively, an electron beam can be used instead of ultraviolet light. As the light source of the electron beam, an α line, a β line, or a γ line can be used.

The adhesive layer is hardened by three-dimensional reticulation by light irradiation, and the adhesion of the adhesive layer is lowered. At this time, as described above, the adhesive sheet of the present invention does not excessively adhere to the wafer or the like even when heated, so that the adhesion can be sufficiently reduced by irradiation with ultraviolet rays or the like.

(4) Expansion and pickup steps

In the expansion/pickup step, the adhesive sheet is stretched to enlarge the distance between the semiconductor wafer or the semiconductor component, and the wafer or the component is lifted up by a thimble or the like. Next, the wafer or the part is adsorbed by a vacuum collet or a pneumatic tweezers, and the adhesive layer of the adhesive sheet is peeled off and picked up. In this case, since the adhesive sheet of the present invention can be sufficiently reduced in adhesion by irradiation with ultraviolet rays or the like, peeling between the wafer or the component and the adhesive layer is facilitated, and good pickup property can be obtained without Adverse conditions such as adhesive residue.

<Manufacture of adhesive sheets>

As a method of forming an adhesive layer on a substrate, for example, a coating machine such as a concave coater, a notch coater, a bar coater, a knife coater or a roll coater is used to directly apply an adhesive. A method of coating on a substrate, or a method of applying an adhesive to a release film, drying it, and bonding it to a substrate film. The adhesive can also be printed onto the substrate by letterpress, gravure, lithographic, flexographic, plano-convex or screen printing.

The adhesive sheet of the present embodiment is suitably used for attaching an electronic component assembly called a workpiece in a cutting step and a back grinding step in the manufacturing process of an electronic component.

The adhesive composition and the adhesive sheet in the examples and the comparative examples were produced in accordance with the following formulations. The main formulations and the results of the respective experimental examples are shown in Table 3.

The hardening type adhesive was applied onto a separator film made of polyethylene terephthalate, and the thickness of the adhesive layer after drying was 20 μm. The adhesive layer was laminated on a base film, and aged at 40 ° C for 7 days to obtain an adhesive sheet. In the base film, a Zn salt of an ethylene-methacrylic acid-alkyl methacrylate copolymer, which is an ionomer resin, is mainly used, and MFR 値 1.0 g/10 minutes (JIS K7210, 210 ° C), melting point 86 °C, containing Zn ²⁺ ions (manufactured by Mitsui DuPont Chemical Co., Ltd., part number: HM1855), which was extruded with a T die to form a 100 μm film.

[Photohardenable Adhesive]

[(Meth)acrylate copolymer] A-1: Acrylic rubber AR53L manufactured by Zeon Co., Ltd.; can be made up of 54% ethyl acrylate, 19% butyl acrylate, and 24% methoxyethyl acrylate. The copolymer is obtained by emulsion polymerization. A-2: SK-Dyne 1496 manufactured by Soken Chemical Co., Ltd.; can be obtained by solution polymerization of a copolymer of 2-ethylhexyl acrylate 96% and 2-hydroxyethyl acrylate 4%.

[Photopolymerizable compound]

B-1: a bisphenol A type epoxy acrylate represented by the following formula. It is a commercially available product of a tetrafunctional acrylate and a weight average molecular weight of 1,000 (manufactured by Showa Denko Co., Ltd., product name: RIPOXY PX-390HT). Contains hydroxyl groups.

[Chemical 2]

(In the chemical formula, R represents a hydrogen molecule or a (meth) acrylate group. n represents an integer of 1 or more.)

B-2: a terminal isocyanate compound obtained by reacting an OH terminal of pentaerythritol with hexamethylene diisocyanate, and further reacting with 2-hydroxyethyl acrylate to form a vinyl group having 4 weight average molecular weights of 1000 per molecule. Amino acrylate oligomer (synthetic). Does not contain hydroxyl groups.

Further, the weight average molecular weight is a value measured by gel permeation chromatography (GPC) in such a manner as to convert the weight average molecular weight of polystyrene.

[Polyfunctional isocyanate curing agent] C-1: CORONATE L-45E manufactured by Nippon Polyurethane Industry Co., Ltd.; trimethylolpropane adduct of 2,4-tolyl diisocyanate. C-2: CORONATE HL manufactured by Nippon Polyurethane Industry Co., Ltd.; trimethylolpropane adduct of hexamethylene diisocyanate.

[Photopolymerization initiator] D-1: IRGACURE127 manufactured by BASF JAPAN Co., Ltd.; 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propenyl)-benzyl]-benzene }}-2-methyl-propan-1-one. D-2: IRGACURE 651 manufactured by BASF JAPAN; diphenylmethyl ketal.

(1) Method for determining TOC concentration

The obtained adhesive sheet was adjusted in the following procedure, and the sample was measured by a total organic carbon meter (ON-LINE TOC-VCHS manufactured by Shimadzu Corporation) in accordance with the "combustion oxidation-infrared TOC analysis method" of JIS K 0101 20.1. TOC concentration. 1. Cut the adhesive sheet into 50 mm × 50 mm. 2. 500 Ml of pure water having a TOC concentration of 5 ppb or less was placed in a sampling bottle which had been thoroughly washed with pure water, and the adhesive sheet of the peeled separator film was shaken in pure water for 30 seconds. 3. Dip the adhesive sheet down in pure water. 4. Let stand at 23 °C. 5. Remove the adhesive after 24 hours. 6. The TOC concentration of the solution was measured three times, and the average value was taken as the measured value.

The TOC concentration obtained by the above method was evaluated by the following criteria. ◎ (excellent): less than 1.0 mg / L ○ (good): 1.0 mg / L or more and 3.0 mg / L or less × (bad): more than 3.0 mg / L

(2) Evaluation of wafer retention and pick-up

The obtained adhesive sheet was bonded to a tantalum wafer having a diameter of 8 inches × 0.1 mm and a ring frame forming a virtual circuit pattern. Next, it was heated at 75 ° C for 30 minutes using an oven during heating. After that, each step of cutting and picking is performed.

The conditions of the cutting step are as follows. Cutting device: DAD341 manufactured by DISCO Cutting board: NBC-ZH205O-27HEEE manufactured by DISCO. Cutting board shape: outer diameter 55.56mm, tooth width 35μm, inner diameter 19.05mm. Cutting plate rotation speed: 40,000 rpm Cutting plate Feeding speed: 50 mm/sec Cutting size: 1.5 mm angle Cutting depth for adhesive sheet: 15 μm Cutting water temperature: 25°C Cutting water volume: 1.0 liter/min

The conditions for the pickup step are as follows. Pickup device: CAP-300II made by Canon-Machinery Co., Ltd. Expansion amount: 8mm Thimble shape: 70μmR Number of thimbles: 1 thimble jacking height: 0.5mm

In the cutting step and the picking step, the following evaluations were made.

(2-1) Wafer retention

For wafer retention, after the dicing step, the residual rate of the semiconductor wafer fixed on the adhesive sheet by the semiconductor wafer was evaluated by the following criteria. ◎(Excellent): The wafer scatters less than 5% ○(good): The wafer scatters more than 5% and is less than 10% × (bad): the wafer scatters more than 10%

(2-2) Pickup

For the pickup property, in the pickup step, the transfer success rate (pickup success rate) of the transfer of the semiconductor wafer using the transfer adhesive sheet was evaluated by the following criteria. ◎(Excellent): The pick-up success rate of the wafer is over 95%. ○(Good): The pick-up success rate of the wafer is 80% or more and less than 95% × (bad): the chip pick-up success rate is less than 80%

no

no

Claims (10)

An adhesive sheet comprising an adhesive sheet formed by laminating an adhesive layer on a substrate, the adhesive layer being a photocurable adhesive layer comprising a (meth) acrylate copolymer 100 5 parts by mass to 200 parts by mass of the photopolymerizable compound, 0.1 to 20 parts by mass of the polyfunctional isocyanate curing agent, and 0.1 to 20 parts by mass of the photopolymerization initiator, and the weight average molecular weight of the photopolymerizable compound is 500 or more. The adhesive sheet was adjusted to have a size of 50 mm × 50 mm, and after immersing in 500 mL of pure water for 24 hours, the concentration of total organic carbon (TOC: Total Organic Carbon) dissolved and precipitated was 5.0 mg/L or less. The adhesive sheet according to claim 1, wherein the photocurable adhesive contains 40 to 150 parts by mass of a photopolymerizable compound, 1 to 15 parts by mass of a polyfunctional isocyanate curing agent, and 1 to 10 parts of a photopolymerization initiator. Parts by mass. The adhesive sheet according to any one of claims 1 to 2, wherein the adhesive sheet is a dicing tape used in a manufacturing process of an electronic component, the manufacturing process comprising: (a) a step of attaching the dicing tape to the semiconductor wafer or substrate and the annular frame; (b) cutting the semiconductor wafer or substrate to form a semiconductor wafer or a semiconductor component; (c) illuminating the adhesive sheet with active light a step of illuminating the light; (d) an expanding step of stretching the adhesive sheet for expanding the distance between the semiconductor wafer or the semiconductor component; and (e) a step of picking up the semiconductor wafer or the semiconductor component from the adhesive sheet. The adhesive sheet according to any one of claims 1 to 3, wherein the electronic component is an LED. An adhesive sheet comprising an adhesive layer formed by laminating an adhesive layer on a substrate, the adhesive layer containing as an essential component a (meth) acrylate copolymer, a photopolymerizable compound, and a hardener, the adhesive The concentration of total organic carbon (TOC: Total Organic Carbon) dissolved and dissolved in pure water is 3.0 mg/L or less, and the adhesive layer contains 100 parts by mass of a (meth) acrylate copolymer and a polyfunctional isocyanate curing agent 0.1 to 0.1. 20 parts by mass and 0.1 to 20 parts by mass of the photopolymerization initiator, the (meth) acrylate copolymer and the photopolymerizable compound contain a hydroxyl group. The adhesive sheet of claim 5, wherein the hydroxyl group forms a chemical bond with the isocyanate group. The adhesive sheet according to claim 5, wherein the adhesive layer contains 5 to 200 parts by mass of the photopolymerizable compound. The adhesive sheet according to any one of claims 5 to 7, wherein the adhesive layer contains 100 parts by mass of a (meth) acrylate copolymer, 40 to 150 parts by mass of a photopolymerizable compound, and a polyfunctional group. 1 to 15 parts by mass of the isocyanate curing agent and 1 to 10 parts by mass of the photopolymerization initiator. The adhesive sheet according to any one of claims 5 to 8, wherein the adhesive sheet is a dicing tape used in a manufacturing process of an electronic component, the manufacturing process comprising: (a) a step of attaching the dicing tape to the semiconductor wafer or substrate and the annular frame; (b) cutting the semiconductor wafer or substrate to form a semiconductor wafer or a semiconductor component; (c) illuminating the adhesive sheet with active light a step of illuminating the light; (d) an expanding step of stretching the adhesive sheet for expanding the distance between the semiconductor wafer or the semiconductor component; and (e) a step of picking up the semiconductor wafer or the semiconductor component from the adhesive sheet. The adhesive sheet according to claim 9, wherein the electronic component is an LED.