WO2014200071A1

WO2014200071A1 - Adhesive sheet

Info

Publication number: WO2014200071A1
Application number: PCT/JP2014/065629
Authority: WO
Inventors: 友也津久井; 剛介中島
Original assignee: 電気化学工業株式会社
Priority date: 2013-06-14
Filing date: 2014-06-12
Publication date: 2014-12-18
Also published as: TW201502234A; TWI639673B; JPWO2014200071A1

Abstract

Provided is an adhesive sheet that is such that the total organic carbon concentration in washing water during a dicing process and after the dicing process is an extremely low level, there is no spattering of chips during the dicing process, pick-up is easily performed, and it is difficult for glue residue to arise. The present invention provides an adhesive sheet resulting from laminating an adhesive layer onto a substrate, wherein the adhesive layer is a photocurable adhesive layer, the photocurable adhesive layer contains 100 parts by mass of a (meth)acrylic ester copolymer, 5-200 parts by mass of a photocurable compound, 0.1-20 parts by mass of a polyfunctional isocyanate curing agent, and 0.1-20 parts by mass of a photoinitiator, the weight average molecular weight of the photocurable compound is at least 500, the adhesive sheet is adjusted to the size of 50 mm x 50 mm, and the total organic carbon (TOC) concentration leaching out when immersed in 500 mL of pure water for 24 hours is no greater than 5.0 mg/L.

Description

Adhesive sheet

The present invention relates to an adhesive sheet used in the manufacturing process of electronic components.

The semiconductor wafer or substrate is attached to each process such as cutting (dicing), stretching (expanding) the adhesive sheet, and peeling (pickup) the element small piece from the adhesive sheet after bonding the adhesive sheet. Is done. The pressure-sensitive adhesive sheet (dicing tape) used in these processes has sufficient adhesive strength to the cut element pieces (chips) in the dicing process, but does not have adhesive residue during the pick-up process. It is hoped that is reduced.

As the pressure-sensitive adhesive sheet, there is one in which a pressure-sensitive adhesive layer that undergoes a polymerization and curing reaction with ultraviolet light or the like is applied on a base material that is transparent to active rays such as ultraviolet light and / or electron beams. In this pressure-sensitive adhesive sheet, after the dicing step, ultraviolet light or the like is irradiated to the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is polymerized and cured to reduce the pressure-sensitive adhesive force, and then a cut chip is picked up.

As such a pressure-sensitive adhesive sheet, Patent Document 1 and Patent Document 2 disclose a compound having a photopolymerizable unsaturated double bond in its molecule (polyfunctional) that can be three-dimensionally reticulated on the substrate surface by, for example, actinic rays. An adhesive sheet coated with an adhesive containing an oligomer) is disclosed.

JP 2006-049509 A JP 2007-246633 A

Among semiconductor wafer or substrate processing steps, a dicing machine that performs a dicing step uses a thin grindstone called a blade that rotates at high speed, and processes a workpiece while applying grinding water or cooling water.

In addition, this dicing machine is extremely disliked by contaminants (contamination: hereinafter referred to as “contamination” for short) due to the fine grinding powder generated during machining, so it is in the vicinity of the rotating blade. A cleaning nozzle is provided to reduce adhesion of contamination during dicing, and the work after dicing processing is carried into a spin cleaning device provided in the dicing machine, and the cleaning nozzle is moved within the work surface while rotating the work. There is a step of performing spin cleaning by swinging.

In the cleaning water during and after the processing, pure water such as ultrapure water from which organic substances, ionic components, fine particles, bacteria, etc. are highly removed is used. In particular, when manufacturing an electronic component including a semiconductor device, a large amount of pure water is used in the cleaning process, and the demand for the water quality is increasing year by year. Pure water used in the cleaning process of electronic component manufacturing is one of the water quality management items in order to prevent the organic matter contained in the pure water from carbonizing in the subsequent heat treatment process and causing poor insulation. It has been demanded that the total organic carbon (TOC) concentration be extremely low.

Therefore, in the present invention, the total organic carbon concentration is very low in the cleaning water during and after the dicing process, the chips do not scatter during the dicing process, the pickup can be easily performed, and the adhesive residue hardly occurs. The main purpose is to provide an adhesive sheet.

The present invention
A pressure-sensitive adhesive sheet obtained by laminating a pressure-sensitive adhesive layer on a substrate, wherein the pressure-sensitive adhesive layer is a photocurable pressure-sensitive adhesive layer, and the photocurable pressure-sensitive adhesive is
100 parts by weight of a (meth) acrylic acid ester copolymer,
5 to 200 parts by mass of a photopolymerizable compound,
0.1 to 20 parts by mass of a polyfunctional isocyanate curing agent;
0.1 to 20 parts by mass of a photopolymerization initiator,
The photopolymerizable compound has a weight average molecular weight of 500 or more,
The pressure-sensitive adhesive sheet is adjusted to a size of 50 mm × 50 mm and has a total organic carbon (TOC) concentration of 5.0 mg / L or less that is eluted when immersed in 500 mL of pure water for 24 hours. .

The present invention also provides:
A pressure-sensitive adhesive sheet obtained by laminating a pressure-sensitive adhesive layer on a substrate,
The pressure-sensitive adhesive layer is
It contains (meth) acrylic acid ester copolymer, photopolymerizable compound, and curing agent as essential components, and the total organic carbon (TOC: Total Organic Carbon) concentration eluted in pure water is 3.0 mg / L or less. ,
The pressure-sensitive adhesive layer is
100 parts by weight of a (meth) acrylic acid ester copolymer,
0.1 to 20 parts by mass of a polyfunctional isocyanate curing agent;
Containing 0.1 to 20 parts by mass of a photopolymerization initiator,
The pressure-sensitive adhesive sheet in which the (meth) acrylic acid ester copolymer and the photopolymerizable compound contain a hydroxyl group.

In addition, (meth) acrylic acid ester copolymer, photopolymerizable compound, and curing agent are contained as essential components, and (meth) acrylic acid ester copolymer and curing agent, and photopolymerizable compound and curing agent, If is not chemically bonded, the organic component of the pressure-sensitive adhesive layer is likely to elute into water. As a result, the TOC concentration contained in the cleaning water at the time of dicing is likely to increase, resulting in an insulation failure of the electronic component.

According to the present invention, in the cleaning water during dicing and after dicing, the total organic carbon concentration is at a very low level, so insulation failure is unlikely to occur, chips do not scatter during dicing, and pickup can be performed easily. There is provided an adhesive sheet that hardly causes adhesive residue.

Hereinafter, preferred embodiments for carrying out the present invention will be described. In addition, embodiment described below shows an example of typical embodiment of this invention, and, thereby, the range of this invention is not interpreted narrowly.

<< First Embodiment >>
The pressure-sensitive adhesive sheet according to this embodiment is
A pressure-sensitive adhesive sheet obtained by laminating a pressure-sensitive adhesive layer on a substrate, wherein the pressure-sensitive adhesive layer is a photocurable pressure-sensitive adhesive layer, and the photocurable pressure-sensitive adhesive is
100 parts by weight of a (meth) acrylic acid ester copolymer,
5 to 200 parts by mass of a photopolymerizable compound,
0.1 to 20 parts by mass of a polyfunctional isocyanate curing agent;
0.1 to 20 parts by mass of a photopolymerization initiator,
The photopolymerizable compound has a weight average molecular weight of 500 or more,
The pressure-sensitive adhesive sheet is adjusted to a size of 50 mm × 50 mm, and the total organic carbon (TOC) concentration eluted when immersed in 500 mL of pure water for 24 hours is 5.0 mg / L or less.

In addition, the pressure-sensitive adhesive sheet according to this embodiment is
A pressure-sensitive adhesive sheet obtained by laminating a pressure-sensitive adhesive layer on a base material, wherein the pressure-sensitive adhesive sheet is adjusted to a size of 100 mm × 100 mm and is dissolved in water for 24 hours to dissolve all organic carbon (TOC: Total Organic) Carbon) concentration is 0-5 mg / L.

<Adhesive layer>
As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, polymers obtained by polymerizing acrylic acid, methacrylic acid and ester monomers thereof, unsaturated monomers copolymerizable with these monomers (for example, vinyl acetate, styrene, acrylonitrile) and There is a copolymer obtained by copolymerizing. In the pressure-sensitive adhesive sheet of the present embodiment, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is preferably an acrylic polymer that is easy to design the pressure-sensitive adhesive force, and the adhesive force can be adjusted more precisely by containing a curing agent. And it is preferable that at least one of the acrylic monomers constituting the acrylic polymer contains a functional group-containing monomer. This functional group-containing monomer is preferably blended and polymerized in an acrylic polymer in an amount of 0% by mass to 10% by mass. If the blending ratio of the functional group-containing monomer is 0.01% by mass or more, the adhesive strength to the adherend is sufficiently strong and the generation around the water tends to be suppressed. If the blending ratio is 10 mass% or less, the adhesive force to the adherend will not be too high, so that it is possible to suppress the occurrence of adhesive residue.

Examples of the main monomer of the acrylic polymer include butyl (meth) acrylate, 2-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, octyl (meth) acrylate, 2- Ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, tridecyl (meth) acrylate, myristyl ( Examples include (meth) acrylic monomers such as (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, and benzyl (meth) acrylate.

As the acrylic monomer, those having a monomer containing a functional group at least in part are particularly preferable. As the monomer containing this functional group, a monomer having a hydroxyl group, a carboxyl group, an epoxy group, an amide group, an amino group, a methylol group, a sulfonic acid group, a sulfamic acid group, or a (phosphite) ester group Is preferred. Of these, vinyl compounds having these functional groups are particularly preferable, and vinyl compounds having hydroxyl groups are particularly preferable. In addition, the acrylate mentioned later is included in the vinyl compound here.

Examples of the functional group-containing monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate.
Examples of the monomer having a carboxyl group include (meth) acrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, acrylamide N-glycolic acid, and cinnamic acid.

Examples of the monomer having an epoxy group include allyl glycidyl ether and (meth) acrylic acid glycidyl ether.

Examples of the monomer having an amide group include (meth) acrylamide.

Examples of the monomer having an amino group include N, N-dimethylaminoethyl (meth) acrylate.

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

In the pressure-sensitive adhesive layer of this embodiment, after the pressure-sensitive adhesive layer is cured by reacting the acrylic polymer and the curing agent, the monomer containing a carboxyl group constituting the acrylic polymer is It is preferably 0.1 to 10% by mass or less in the acrylic polymer. That is, according to another expression, among functional group-containing monomers obtained by reacting an adhesive with a curing agent, the functional group-containing monomer containing a carboxyl group is preferably 10% by mass or less. By using a carboxyl group-containing functional group-containing monomer, the adhesion to metal increases, so the carboxyl group-containing functional group-containing monomer after reacting with the curing agent exceeds 10% by mass. In addition, the adhesive strength to the metal is high, and the adhesive residue tends to be generated. Therefore, the monomer having a carboxyl group is preferably one that easily disappears by reaction with a curing agent. For example, (meth) acrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, acrylamide N Glycolic acid and cinnamic acid are preferably used.

(Curing agent)
In the adhesive sheet of this embodiment, it is preferable to mix | blend a hardening | curing agent with the adhesive used for an adhesive layer. When mix | blending a hardening | curing agent, it is preferable that the compounding ratio of a hardening | curing agent is 0.1 to 10 mass parts with respect to 100 mass parts of acrylic polymers. This is because if the blending ratio of the curing agent is 0.1 parts by mass or more and 10 parts by mass or less, generation of adhesive residue can be suppressed.

As the curing agent to be blended in the pressure-sensitive adhesive layer, there are a polyfunctional isocyanate curing agent, a polyfunctional epoxy curing agent, an azirine compound, a melamine compound, and the like, and preferably a polyfunctional isocyanate curing agent and a polyfunctional epoxy curing agent. By using a polyfunctional epoxy curing agent or a polyfunctional isocyanate curing agent as at least a part of the above curing agent, it is possible to selectively cause a functional group-containing monomer having a carboxyl group to react and disappear. It is possible to adjust the amount of the functional group-containing monomer having a carboxyl group after curing.

Examples of the polyfunctional isocyanate curing agent include an aromatic polyisocyanate curing agent, an aliphatic polyisocyanate curing agent, and an alicyclic polyisocyanate curing agent. In addition, an aliphatic polyisocyanate curing agent, particularly a xamethylene diisocyanate curing agent among them is preferable. The reason why this isocyanate curing agent is good is that it can impart flexibility to the pressure-sensitive adhesive and is also effective for an adherend having irregularities.

The aromatic polyisocyanate is not particularly limited, and for example, 1,3-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2, , 6-tolylene diisocyanate, 4,4′-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4′-diphenyl ether diisocyanate, 4,4 ', 4 "-triphenylmethane triisocyanate, ω, ω'-diisocyanate-1,3-dimethylbenzene, ω, ω'-diisocyanate-1,4-dimethylbenzene, ω, ω'-diisocyanate-1,4- Diechi Benzene, 1,4-tetramethylxylylene diisocyanate, and 1,3-tetramethylxylylene diisocyanate and the like.

The aliphatic polyisocyanate is not particularly limited. For example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene Examples thereof include diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate.

The alicyclic polyisocyanate is not particularly limited. For example, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl -2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), 1,4-bis (isocyanatomethyl) cyclohexane, and 1,4-bis (isocyanatomethyl) cyclohexane There is.

Among polyisocyanates, 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate 4,4′-toluidine diisocyanate and hexamethylene diisocyanate are preferably used.

The polyfunctional epoxy curing agent mainly means a compound having two or more epoxy groups and one or more tertiary nitrogen atoms. N · N-glycidylaniline, N · N-glycidyltoluidine, mN · N— Glycidylaminophenyl glycidyl ether, pN · N-glycidylaminophenyl glycidyl ether, triglycidyl isocyanurate, N · N · N '· N'-tetraglycidyldiaminodiphenylmethane, N · N · N' · N'-tetraglycidyl -M-xylylenediamine, N · N · N ′ · N ′ · N ″ -pentaglycidyldiethylenetriamine and the like.

The pressure-sensitive adhesive can be a pressure-sensitive pressure-sensitive adhesive mainly composed of an acrylic polymer and a curing agent, but in addition to the acrylic polymer and the curing agent, a photopolymerizable compound, a photopolymerization initiator, a tackifying resin, and an additive It can be used as a photo-curing pressure-sensitive adhesive using etc.

(Photopolymerizable compound)
Examples of the photopolymerizable compound include trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene. Glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, cyanuric acid triethyl acrylate, commercially available oligoester acrylate, and the like are used.

As the photopolymerizable compound, a urethane acrylate oligomer can be used in addition to the acrylate compound. The urethane acrylate oligomer is obtained by reacting a (meth) acrylate having a hydroxy group with a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound such as a polyester type or a polyether type with a polyvalent isocyanate compound.

Examples of the polyvalent isocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane 4,4-diisocyanate, trimethylhexamethylene diisocyanate. , Hexamethylene diisocyanate, isophorone diisocyanate and the like can be used. Examples of the (meth) acrylate having a hydroxy group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol (meth) acrylate, pentaerythritol triacrylate, and glycidol di (meth). Acrylate, dipentaerythritol monohydroxypentaacrylate, etc. are used.

As the photopolymerizable compound, a urethane acrylate oligomer having 4 or more vinyl groups is preferable because the adhesive is cured well after irradiation with ultraviolet rays or the like.

The weight average molecular weight of the photopolymerizable compound is preferably 500 or more, and more preferably 1000 or more. If the weight average molecular weight of the photopolymerizable compound is small, the TOC concentration contained in the washing water at the time of dicing tends to increase, which may cause insulation failure of electronic components.

The blending 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 with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer. If the blending amount of the photopolymerizable compound is reduced, the peelability of the pressure-sensitive adhesive sheet after irradiation is reduced, and the pick-up failure of the semiconductor chip is likely to occur. On the other hand, when the blending amount of the photopolymerizable compound is increased, pick-up failure is liable to occur due to the glue being picked up during dicing, and a minute glue residue is generated due to a reaction residue, which causes contamination.

(Photopolymerization initiator)
As the photopolymerization initiator, benzoin, benzoin alkyl ethers, acetophenones, anthraquinones, thioxanthones, ketals, benzophenones or xanthones are used.

Examples of benzoin include benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin propyl ether.
Examples of acetophenones include benzoin alkyl ethers, acetophenone, 2,2-dimethoxy-2-acetophenone, 2,2-diethoxy-2-acetophenone, 1,1-dichloroacetophenone, and the like.
Anthraquinones include 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiarybutylanthraquinone, 1-chloroanthraquinone and the like.
Examples of thioxanthones include 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone.
Examples of ketals include acetophenone dimethyl ketal, benzyldimethylmethal, benzyldiphenylsulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, β-chloranthraquinone, and the like.
Of these, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] having a hydroxyl group capable of reacting with an isocyanate curing agent in order to prevent contamination of the adherend -Phenyl} -2-methyl-propan-1-one (manufactured by BASF Japan, product name IRGACURE127) is preferred.

The blending amount of the photopolymerization initiator is preferably 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic acid ester polymer. If the blending amount is too small, the peelability of the pressure-sensitive adhesive sheet after irradiation is lowered, and the pick-up failure of the semiconductor chip is likely to occur. On the other hand, if the amount is too large, the photopolymerization initiator bleeds out to the pressure-sensitive adhesive surface, causing contamination.

The photopolymerization initiator may be used in combination with one or more conventionally known photopolymerization accelerators, if necessary. A benzoic acid type | system | group, a tertiary amine, etc. can be used for a photoinitiator. Examples of the tertiary amine include triethylamine, tetraethylpentamine, dimethylamino ether and the like.

(Tackifying resin)
The tackifier resin is a terpene phenol resin that is completely or partially hydrogenated with a terpene phenol resin.

The terpene phenol resin can be produced, for example, by reacting 1 mol of a terpene compound with 0.1 to 50 phenols.

Examples of terpene compounds include myrcene, alloocimene, osmene, α-pinene, β-pinene, dipentene, limonene, α-ferrandrene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, Examples include α-terpineol, β-terpineol, γ-terpineol, camphene, tricyclene, sabinene, paramentadienes, and carenes. Among these compounds, α-pinene, β-pinene, limonene, myrcene, alloocimene and α-terpinene are particularly preferably used in the present invention.

Examples of the phenols include, but are not limited to, phenol, cresol, xylenol, catechol, resorcin, hydroquinone, bisphenol A, and the like.

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

The hydroxyl value of the fully or partially hydrogenated terpene phenol resin is preferably 50 to 250. When the hydroxyl value is less than 50, the reaction with the isocyanate curing agent is not sufficient, bleeds out to the surface of the pressure-sensitive adhesive, causing contamination, and when it exceeds 250, the viscosity increases and the (meth) acrylic acid ester This is because uneven mixing with a polymer or the like occurs and the pickup characteristics are not stable.

The hydrogenation method is not particularly limited, and for example, a noble metal such as palladium, ruthenium, rhodium or the like supported on a carrier such as activated carbon, activated alumina, or diatomaceous earth is used as a catalyst. The hydrogenation rate can be measured by bromine number measurement, iodine number measurement or the like.

The hydrogenation rate of the completely or partially hydrogenated terpene phenol resin is preferably 30 mol% or more, more preferably 70 mol% or more. When the amount is less than 30 mol%, the adhesive force is not sufficiently lowered due to the reaction inhibition of the photopolymerizable compound by irradiation with actinic rays, and the pickup property is lowered.

The blending ratio of the fully or partially hydrogenated terpene phenol resin is preferably 0.5 parts by mass or more and 100 parts by mass or less, and 1.0 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer. Less than the mass part is more preferable. If the completely or partially hydrogenated terpene phenol resin is 0.5 parts by mass or more, the adhesive strength is not too low, so the retention of the semiconductor chip is maintained during dicing, and if it is 100 parts by mass or less, the pickup is poor. Can be suppressed.

(Additives, etc.)
Various additives such as a softening agent, 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 pressure-sensitive adhesive layer is preferably 1 μm to 50 μm, particularly preferably 5 μm to 35 μm. If the pressure-sensitive adhesive layer is too thick, the pressure-sensitive adhesive strength becomes too high and the pick-up property is lowered. On the other hand, if the pressure-sensitive adhesive layer is too thin, the pressure-sensitive adhesive force becomes too low, chip retention during dicing is lowered, and peeling may occur between the ring frame and the sheet.

<Base material>
Examples of the base material include polyvinyl chloride, polyethylene terephthalate, ethylene-vinyl acetate copolymer, ethylene-acrylic acid-acrylate film, ethylene-ethyl acrylate copolymer, polyethylene, polypropylene, propylene-based copolymer Polymers, ethylene-acrylic acid copolymers, and ionomer resins obtained by crosslinking ethylene- (meth) acrylic acid copolymers, ethylene- (meth) acrylic acid- (meth) acrylic acid ester copolymers, etc. with metal ions Is mentioned. The base material may be a mixture or copolymer of these resins, and may be a laminate of films and sheets made of these resins.

It is preferable to use an ionomer resin as a material for the base film. Among ionomer resins, if an ionomer resin obtained by crosslinking a copolymer having an ethylene unit, a methacrylic acid unit, and a (meth) acrylic acid alkyl ester unit with a metal ion such as Na ⁺ , K ⁺ , or Zn ²⁺ is used, cutting is performed. The dust suppressing effect is remarkable and is preferably used.

The base material may be a single layer or a multilayer film or sheet made of the above material, or may be a laminate of films made of different materials. The thickness of the substrate is 50 to 200 μm, preferably 70 to 150 μm.

It is preferable to apply an antistatic treatment to the substrate. Examples of the antistatic treatment include a treatment for adding an antistatic agent to the substrate, a treatment for applying the antistatic agent to the substrate surface, and a treatment by corona discharge.

As the antistatic agent, for example, a quaternary amine salt monomer can be used. Examples of the quaternary amine salt monomer include dimethylaminoethyl (meth) acrylate quaternary chloride, diethylaminoethyl (meth) acrylate quaternary chloride, methylethylaminoethyl (meth) acrylate quaternary chloride, p-dimethyl. Examples include aminostyrene quaternary chloride and p-diethylaminostyrene quaternary chloride. Of these, dimethylaminoethyl methacrylate quaternary chloride is preferred.

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

It is possible to laminate an adhesive on one side of the substrate and make the other side an embossed surface with an average surface roughness (Ra) of 0.3 to 1.5 μm. By installing the embossed surface on the machine table side of the expanding device, the base film can be easily expanded in the expanding process after dicing.

(Slip agent)
In order to improve the expandability after dicing, a slip agent can be applied to the non-adhesive surface of the base material, or the slip agent can be kneaded into the base material.

The slip agent is not particularly limited as long as it is a substance that reduces the friction coefficient of the pressure-sensitive adhesive sheet and the expanding device. For example, silicone compounds such as silicone resins and (modified) silicone oils, fluororesins, hexagonal boron nitride, carbon black, And molybdenum disulfide. These friction reducing agents may mix a plurality of components. Since manufacture of an electronic component is performed in a clean room, it is preferable to use a silicone compound or a fluororesin. Among silicone compounds, a copolymer having a silicone macromonomer unit is particularly preferred because it has good compatibility with the antistatic layer and can achieve a balance between antistatic properties and expandability.

<Manufacturing process of electrical parts>
Specific steps of the electronic component manufacturing method according to the present invention will be described in order.

(1) Affixing process First, in an affixing process, an adhesive sheet is affixed on a semiconductor wafer (or substrate) and a ring frame. The wafer may be a conventional general-purpose wafer such as a silicon 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 chip is sealed with a resin or an LED package substrate.

(2) Dicing process In the dicing process, a silicon wafer or the like is diced into semiconductor chips or semiconductor components.

(3) Light irradiation process In a light irradiation process, actinic rays, such as an ultraviolet-ray, are irradiated to a photocurable adhesive layer from the base material side. As the ultraviolet light source, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, or a metal halide lamp can be used. In addition, an electron beam may be used instead of ultraviolet rays, and α-rays, β-rays, and γ-rays can be used as a light source for the electron beams.

The light-sensitive adhesive layer is three-dimensionally reticulated and cured by light irradiation, and the adhesive strength of the pressure-sensitive adhesive layer is reduced. At this time, as described above, since the pressure-sensitive adhesive sheet according to the present invention does not excessively adhere to a wafer or the like even when heated, a sufficient decrease in adhesive force can be obtained by irradiation with ultraviolet rays or the like.

(4) Expanding and Picking Up Step In the expanding and picking up step, the adhesive sheet is stretched to widen the gap between the semiconductor chips or semiconductor components, and the chip or components are pushed up with a needle pin or the like. Thereafter, the chip or component is adsorbed by a vacuum collet or air tweezers, peeled off from the adhesive layer of the adhesive sheet and picked up. At this time, in the pressure-sensitive adhesive sheet according to the present invention, a sufficient decrease in the adhesive strength is obtained by irradiation with ultraviolet rays or the like, so that peeling between the chip or component and the pressure-sensitive adhesive layer becomes easy, and good pick-up properties are obtained. And no defects such as glue residue occur.

<Manufacture of adhesive sheet>
As a method of forming a pressure-sensitive adhesive layer on a substrate to form a pressure-sensitive adhesive sheet, for example, a method of directly applying a pressure-sensitive adhesive on a substrate with a coater such as a gravure coater, comma coater, bar coater, knife coater or roll coater, There is a method in which a pressure-sensitive adhesive is applied to a release film and dried and bonded to a base film. The adhesive may be printed on the substrate by convex printing, concave printing, flat printing, flexographic printing, offset printing, screen printing, or the like.

The pressure-sensitive adhesive sheet of the present invention is suitably used for attaching an electronic component assembly called a workpiece in a dicing process and a back grinding process, which are electronic component manufacturing processes.

The pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet according to Examples and Comparative Examples were produced with the following prescription. Tables 1 and 2 show the main formulations and the results of each experimental example.

The curable pressure-sensitive adhesive was coated on a polyethylene terephthalate separator film, and coated so that the thickness of the pressure-sensitive adhesive layer after drying was 20 μm. This pressure-sensitive adhesive layer was laminated on a base film and aged at 40 ° C. for 7 days to obtain a pressure-sensitive adhesive sheet. The base film is mainly composed of Zn salt of ethylene-methacrylic acid-methacrylic acid alkyl ester copolymer, which is an ionomer resin, MFR value 1.0 g / 10 min (JIS K7210, 210 ° C.), melting point 86 ° C., A Zn ²⁺ ion-containing (Mitsui / DuPont Polychemical Co., Ltd., product number: HM1855) film formed to 100 μm by T-die extrusion was used.

[Photo-curing adhesive]
[(Meth) acrylic acid ester copolymer]
A-1: Acrylic rubber AR53L manufactured by Nippon Zeon Co., Ltd .; a copolymer of 54% ethyl acrylate, 19% butyl acrylate and 24% methoxyethyl acrylate, obtained by emulsion polymerization.
A-2: SK dyne 1496 manufactured by Soken Chemical Co .; a copolymer of 96% 2-ethylhexyl acrylate and 4% 2-hydroxyethyl acrylate, obtained by solution polymerization.
[Photopolymerizable compound]
Urethane acrylate having 4 vinyl groups per molecule (synthetic product) obtained by further reacting 2-hydroxyethyl acrylate with a terminal isocyanate compound obtained by reacting hexamethylene diisocyanate with the OH terminal of pentaerythritol. The number average molecular weight is a value measured as a number average molecular weight in terms of polystyrene by gel permeation chromatography (GPC).
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
[Multifunctional isocyanate curing agent]
C-1: Coronate L-45E manufactured by Nippon Polyurethane; Trimethylolpropane adduct of 2,4-tolylene diisocyanate.
C-2: Coronate HL manufactured by Nippon Polyurethane Co .; trimethylolpropane adduct of hexamethylene diisocyanate.
(Photopolymerization initiator)
D-1: IRGACURE127 manufactured by BASF Japan; 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one.
D-2: IRGACURE651 manufactured by BASF Japan Ltd .; benzyldimethyl ketal.

(1) Measuring method of TOC concentration The obtained pressure-sensitive adhesive sheet was prepared according to the following procedure, and an all organic carbon meter (manufactured by Shimadzu Corporation) in accordance with JIS K 0101 20.1 “combustion oxidation-infrared TOC analysis method” ON-LINE TOC-VCHS), the TOC concentration in the sample was measured.
1. Cut the adhesive sheet to 50 mm x 50 mm.
2. 500 mL of pure water having a TOC concentration of 5 ppb or less is added to a sample bottle sufficiently washed with pure water, and the pressure-sensitive adhesive sheet from which the separator film has been peeled is shaken in pure water for 30 seconds.
3. Immerse it in pure water with the adhesive side of the adhesive sheet facing down.
4). Let stand at 23 ° C.
5. After 24 hours, the adhesive sheet is taken out.
6). The TOC concentration of the solution is measured three times, and the average value is taken as the measured value.

The TOC concentration obtained by the above method was evaluated according to the following criteria.
◎ (excellent): 0-2.0mg / L
○ (good): 2.1 to 5.0 mg / L
X (impossible): More than 5.0 mg / L

(2) Evaluation of chip holding property and pick-up property The obtained adhesive sheet was bonded to a ring frame and a silicon wafer having a diameter of 8 inches and a thickness of 0.1 mm on which a dummy circuit pattern was formed. Then, when heating, it heated in oven at 75 degreeC for 30 minutes. Thereafter, dicing and pick-up processes were performed.

The conditions for the dicing process were as follows.
Dicing machine: DAD341 manufactured by DISCO
Dicing blade: NBC-ZH205O-27HEEE made by DISCO
Dicing blade shape: outer diameter 55.56 mm, blade width 35 μm, inner diameter 19.05 mm
Dicing blade rotation speed: 40,000 rpm
Dicing blade feed rate: 50 mm / sec. Dicing size: 1.5 mm square. Cutting depth into adhesive sheet: 15 μm
Cutting water temperature: 25 ° C
Cutting water volume: 1.0 l / min

The conditions for the pick-up process were as follows.
Pickup device: CAP-300II manufactured by Canon Machinery
Expanding amount: 8mm
Needle pin shape: 70μmR
Number of needle pins: 1 Needle pin push-up height: 1.5 mm

The following evaluation was performed in the dicing process and the pickup process.

(2-1) Chip Retention The chip retention was evaluated according to the following criteria based on the remaining ratio of the semiconductor chips held on the adhesive sheet after the dicing process.
◎ (excellent): Chip skipping is less than 5% ○ (good): Chip skipping is 5% or more and less than 10% × (impossible): Chip skipping is 10% or more

(2-2) Pickup property Pickup property was evaluated according to the following criteria based on the rate at which a semiconductor chip could be picked up in the pickup process.
◎ (Excellent): Chip pickup success rate is 95% or more ○ (Good): Chip pickup success rate is 80% or more and less than 95% × (Not possible): Chip pickup success rate is less than 80%

<< Second Embodiment >>
The pressure-sensitive adhesive sheet according to this embodiment is
A pressure-sensitive adhesive sheet obtained by laminating a pressure-sensitive adhesive layer on a substrate,
The pressure-sensitive adhesive layer is
It contains (meth) acrylic acid ester copolymer, photopolymerizable compound, and curing agent as essential components, and the total organic carbon (TOC: Total Organic Carbon) concentration eluted in pure water is 3.0 mg / L or less. ,
The pressure-sensitive adhesive layer is
100 parts by weight of a (meth) acrylic acid ester copolymer,
0.1 to 20 parts by mass of a polyfunctional isocyanate curing agent;
Containing 0.1 to 20 parts by mass of a photopolymerization initiator,
The (meth) acrylic acid ester copolymer and the photopolymerizable compound contain a hydroxyl group.

Examples of the functional group-containing monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate.

Examples of the monomer having a carboxyl group include (meth) acrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, acrylamide N-glycolic acid, and cinnamic acid.

Examples of the monomer having an amide group include (meth) acrylamide.

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

(Curing agent)
In the adhesive sheet of this embodiment, it is preferable to mix | blend a hardening | curing agent with the adhesive used for an adhesive layer. When mix | blending a hardening | curing agent, it is preferable that the compounding ratio of a hardening | curing agent is 0.1 to 20 mass parts with respect to 100 mass parts of acrylic polymers. It is because it can suppress that the adhesive residue generate | occur | produces if the compounding ratio of this hardening | curing agent is 0.1 to 15 mass parts.

(Photopolymerizable compound)
The photopolymerizable compound preferably contains a hydroxyl group. Examples of the photopolymerizable compound containing a hydroxyl group include pentaerythritol triacrylate and dipentaerythritol monohydroxypentaacrylate.

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

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

As the photopolymerizable compound, those having 4 or more vinyl groups are preferred in that the adhesive is cured well after irradiation with ultraviolet rays or the like.

The blending amount of the photopolymerizable compound is preferably 5 parts by mass or more and 200 parts by mass or less, and more preferably 40 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer. If the blending amount of the photopolymerizable compound is reduced, the peelability of the pressure-sensitive adhesive sheet after irradiation is reduced, and the pick-up failure of the semiconductor chip is likely to occur. On the other hand, when the blending amount of the photopolymerizable compound is increased, pick-up failure is liable to occur due to the glue being picked up during dicing, and a minute glue residue is generated due to a reaction residue, which causes contamination.

<Manufacturing process of electronic parts>
Specific steps of the electronic component manufacturing method according to the present invention will be described in order.

The pressure-sensitive adhesive sheet of this embodiment is suitably used for attaching an electronic component assembly called a workpiece in a dicing step and a back grinding step, which are electronic component manufacturing steps.

The pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet according to Examples and Comparative Examples were produced with the following prescription. Table 3 shows the main formulations and the results of each experimental example.

[Photo-curing adhesive]
[(Meth) acrylic acid ester copolymer]
A-1: Acrylic rubber AR53L manufactured by Nippon Zeon Co., Ltd .; a copolymer of 54% ethyl acrylate, 19% butyl acrylate and 24% methoxyethyl acrylate, obtained by emulsion polymerization.
A-2: SK dyne 1496 manufactured by Soken Chemical Co .; a copolymer of 96% 2-ethylhexyl acrylate and 4% 2-hydroxyethyl acrylate, obtained by solution polymerization.
[Photopolymerizable compound]
B-1: A bis-A type epoxy acrylate represented by the following general formula. Commercially available tetrafunctional acrylate having a weight average molecular weight of 1000 (manufactured by Showa Denko KK, product name: Lipoxy PX-390HT). Contains hydroxyl groups.

(In the 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 hexamethylene diisocyanate with the OH terminal of pentaerythritol, further reacted with 2-hydroxyethyl acrylate, and has 4 vinyl groups per molecule and a weight average molecular weight of 1000. Urethane acrylate (synthetic product). No hydroxyl group.
In addition, a weight average molecular weight is the value measured as a weight average molecular weight of polystyrene conversion by the gel permeation chromatography method (GPC).
[Multifunctional isocyanate curing agent]
C-1: Coronate L-45E manufactured by Nippon Polyurethane; Trimethylolpropane adduct of 2,4-tolylene diisocyanate.
C-2: Coronate HL manufactured by Nippon Polyurethane Co .; trimethylolpropane adduct of hexamethylene diisocyanate.
(Photopolymerization initiator)
D-1: IRGACURE127 manufactured by BASF Japan; 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one.
D-2: IRGACURE651 manufactured by BASF Japan Ltd .; benzyldimethyl ketal.

(1) Measuring method of TOC concentration The obtained pressure-sensitive adhesive sheet was prepared according to the following procedure, and an all organic carbon meter (manufactured by Shimadzu Corporation) in accordance with JIS K 0101 20.1 “combustion oxidation-infrared TOC analysis method” ON-LINE TOC-VCHS), the TOC concentration in the sample was measured.
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 is added to a sample bottle sufficiently washed with pure water, and the pressure-sensitive adhesive sheet from which the separator film has been peeled is shaken in pure water for 30 seconds.
3) Soak the adhesive sheet in pure water with the adhesive side down.
4) Let stand at 23 ° C.
5) Remove the adhesive sheet after 24 hours.
6) Measure the TOC concentration of the solution three times, and use the average value as the measured value.

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

Claims

A pressure-sensitive adhesive sheet obtained by laminating a pressure-sensitive adhesive layer on a substrate, wherein the pressure-sensitive adhesive layer is a photocurable pressure-sensitive adhesive layer, and the photocurable pressure-sensitive adhesive is
100 parts by weight of a (meth) acrylic acid ester copolymer,
5 to 200 parts by mass of a photopolymerizable compound,
0.1 to 20 parts by mass of a polyfunctional isocyanate curing agent;
0.1 to 20 parts by mass of a photopolymerization initiator,
The photopolymerizable compound has a weight average molecular weight of 500 or more,
The pressure-sensitive adhesive sheet is adjusted to a size of 50 mm × 50 mm and has a total organic carbon (TOC) concentration of 5.0 mg / L or less that is eluted when immersed in 500 mL of pure water for 24 hours. .
The photocurable pressure-sensitive adhesive includes 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 by mass of a photopolymerizable initiator. Adhesive sheet.
The pressure-sensitive adhesive sheet is a dicing tape, and the dicing tape is
(A) A sticking step of attaching a dicing tape to a semiconductor wafer or substrate and a ring frame;
(B) a dicing step of dicing a semiconductor wafer or substrate into a semiconductor chip or a semiconductor component;
(C) a light irradiation step of irradiating the adhesive sheet with actinic rays,
(D) an expanding step of stretching the pressure-sensitive adhesive sheet to widen the gap between the semiconductor chips or the semiconductor components;
(E) a pickup step of picking up a semiconductor chip or semiconductor component from the adhesive sheet;
The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive sheet is used in a production process of an electronic component including
The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the electronic component is an LED.
A pressure-sensitive adhesive sheet obtained by laminating a pressure-sensitive adhesive layer on a substrate,
The pressure-sensitive adhesive layer is
It contains (meth) acrylic acid ester copolymer, photopolymerizable compound, and curing agent as essential components, and the total organic carbon (TOC: Total Organic Carbon) concentration eluted in pure water is 3.0 mg / L or less. ,
The pressure-sensitive adhesive layer is
100 parts by weight of a (meth) acrylic acid ester copolymer,
0.1 to 20 parts by mass of a polyfunctional isocyanate curing agent;
Containing 0.1 to 20 parts by mass of a photopolymerization initiator,
The pressure-sensitive adhesive sheet in which the (meth) acrylic acid ester copolymer and the photopolymerizable compound contain a hydroxyl group.
The pressure-sensitive adhesive sheet according to claim 5, wherein a chemical bond is formed between the hydroxyl group and the isocyanate group.
The pressure-sensitive adhesive layer is
The pressure-sensitive adhesive sheet according to claim 5, comprising 5 to 200 parts by mass of a photopolymerizable compound.
The pressure-sensitive adhesive layer comprises 100 parts by weight of a (meth) acrylic acid ester copolymer, 40 to 150 parts by weight of a photopolymerizable compound, 1 to 15 parts by weight of a polyfunctional isocyanate curing agent, 1 to 1 part of a photopolymerizable initiator. The pressure-sensitive adhesive sheet according to any one of claims 5 to 7, comprising 10 parts by mass.
The pressure-sensitive adhesive sheet is a dicing tape, and the dicing tape is
(A) A sticking step of attaching a dicing tape to a semiconductor wafer or substrate and a ring frame;
(B) a dicing step of dicing a semiconductor wafer or substrate into a semiconductor chip or a semiconductor component;
(C) a light irradiation step of irradiating the adhesive sheet with actinic rays,
(D) an expanding step of stretching the pressure-sensitive adhesive sheet to widen the gap between the semiconductor chips or the semiconductor components;
(E) a pickup step of picking up a semiconductor chip or semiconductor component from the adhesive sheet;
The pressure-sensitive adhesive sheet according to any one of claims 5 to 8, wherein the pressure-sensitive adhesive sheet is used in a production process of an electronic component comprising
The pressure-sensitive adhesive sheet according to claim 9, wherein the electronic component is an LED.