JP2000044894A - Peelable tacky agent composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition capable of exhibiting a good tacky property, peelable property, soil resistance, metal corrosion resistance, etc., by containing a specific acrylic tacky agent, a specific reaction material, a photopolymerization initiator and a cross-linking agent. SOLUTION: This peelable type tacky agent composition contains (A) an acrylic tacky agent having at least one kind of carboxyl group, hydroxy group, amide group, glycidyl group, amino group or sulfone group, also >=200,000 weight-average molecular weight and having (-)60-(-)30 deg.C glass transition temperature, (B) a reaction material of a trimer of a diisocyanate compound with an acrylic compound, (C) a photopolymerization initiator and (D) a cross- linking agent. Further, it is preferable that the blending amount of the component (B) is 5-75 wt.% based on the total amount of the components (A) and (B), and the blending amount of the compound (D) is 0.05-10 pt.wt. based on the 100 pts.wt. total amount of the components (A) and (B). This composition can be effectively used for a temporary adhesion as a tacky sheet for fixing a semiconductor in a dicing process of a semiconductor wafer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used as an adhesive such as an adhesive sheet for temporarily protecting a surface of a metal plate, a glass plate, a plastic plate or the like, or an adhesive sheet for fixing a semiconductor in a dicing process of a semiconductor wafer or the like. And a removable pressure-sensitive adhesive composition.

[0002]

2. Description of the Related Art In recent years, an adhesive sheet has been temporarily used as a protective sheet on a surface of a metal plate, a glass plate, a plastic plate, or the like in order to prevent rust on the surface (in the case of a metal plate), dirt or damage. For example, an adhesive sheet is used for temporary bonding in a dicing process of a semiconductor wafer or the like. The pressure-sensitive adhesive used for these pressure-sensitive adhesive sheets has a sufficient adhesive strength when applied to an adherend, and when peeled (cured by ultraviolet irradiation or the like), the adhesive strength is sufficiently reduced, In addition, it is required that the surface of the adherend has no contamination (residual adhesive). Japanese Patent Application Laid-Open No. 62-1533 discloses an adhesive for such use.
No. 76 discloses a pressure-sensitive adhesive in which a radiation-polymerizable compound comprising a urethane acrylate oligomer having a molecular weight of 3,000 to 10,000 is compounded. It is intended to sharply reduce the adhesive strength of the adhesive. Japanese Patent Application Laid-Open No. 9-328663 discloses a pressure-sensitive adhesive mainly composed of an elastomer, a tackifier, a curing agent, an ultraviolet-crosslinkable oligomer and / or monomer, and a polymerization initiator for the same purpose.

[0003]

However, as a result of examining the above disclosed technology, the pressure-sensitive adhesive disclosed in Japanese Patent Application Laid-Open No. 62-153376 shows that the pressure-sensitive adhesive strength at the time of re-peeling (after curing) of the pressure-sensitive adhesive does not decrease. Although it is recognized, the adhesive remains on the adhered surface after re-peeling, and further, when used for temporary bonding in the dicing process of the semiconductor wafer described above, chips are scattered at the time of dicing or chips are expanded at the time of expansion. There is a problem of peeling and falling off.
In the technology disclosed in Japanese Patent Publication No. 663, when used for the same purpose, a drawback that the force applied to the pickup is large and the chip may be broken particularly when the chip is thin is found to be satisfactory. It wasn't good.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve such a problem.
(A) having at least one functional group of a carboxyl group, a hydroxyl group, an amide group, a glycidyl group, an amino group, and a sulfonic acid group in the molecule, and having a weight average molecular weight of 200,000 or more and a glass transition temperature of -60 to A removable pressure-sensitive adhesive composition comprising an acrylic pressure-sensitive adhesive at −30 ° C., (b) a reaction product of a trimer of a diisocyanate compound and an acrylic compound, (c) a photopolymerization initiator, and (d) a crosslinking agent. However, the adhesiveness, removability, contamination resistance, etc. are good, and the dicing suitability for the temporary bonding application in the dicing process of the semiconductor wafer described above,
The present invention was found to be excellent in expandability, pickup efficiency, etc., and was very useful, and completed the present invention.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described specifically. The acrylic pressure-sensitive adhesive (a) used in the present invention includes:
It is necessary that the molecule has at least one functional group of a carboxyl group, a hydroxyl group, an amide group, a glycidyl group, an amino group, and a sulfonic acid group. Specifically, an acrylic acid alkyl ester or a methacrylic acid alkyl ester It is a copolymer of a main monomer of the system and a monomer containing the above functional group. As the main monomer, one or two or more alkyl acrylates or alkyl methacrylates having an alkyl group having about 1 to 12 carbon atoms are used. Among them, the alkyl group has about 4 to 12 carbon atoms. Of these, alkyl acrylates and alkyl methacrylates are preferably used. Examples of the alkyl acrylate having about 4 to 12 carbon atoms in the alkyl group include n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, n-hexyl acrylate, and acrylic 2-ethylhexyl acid, n-octyl acrylate, lauryl acrylate, and the like.
Examples of the alkyl methacrylate include n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, and n-methacrylic acid.
-Hexyl, n-octyl methacrylate, lauryl methacrylate and the like.

The above-mentioned functional group-containing monomers include carboxyl groups such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, acrylamide N-glycolic acid and cinnamic acid. Monomers, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-chloro-2-hydroxy methacrylate Propyl, tetrahydrofurfuryl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, diethylene glycol acrylate, polyethylene glycol acrylate, N-
Hydroxyl-containing monomers such as methylol acrylamide and N-methylol methacrylamide; glycidyl group-containing monomers such as glycidyl methacrylate and allyl glycidyl methacrylate; acrylamide, methacrylamide;
(N-butoxyalkyl) acrylamide, N- (n-
Amide group-containing monomers such as butoxyalkyl) methacrylamide, amino group-containing monomers such as acrylamido-3-methylbutylmethylamine, dimethylaminoalkylacrylamide, and dimethylaminoalkylmethacrylamide; olefinsulfonic acids (ethylenesulfonic acid,
Sulfonic acid group-containing monomers such as allylsulfonic acid and methallylsulfonic acid), 2-acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid and salts thereof are used.

[0007] The copolymerization ratio (weight ratio) of the main monomer and the monomer containing the above functional group is 99.9 / 0.1-70 /
When the copolymerization ratio is out of the above range, the pressure-sensitive adhesive composition may remain on the surface to be adhered upon re-peeling, which is not preferable. Further, the above copolymer may be copolymerized with an unsaturated compound (monomer) other than the above without departing from the gist of the present invention. Examples of such a monomer include 2-methoxyethyl acrylate and methacrylic acid. Alkyl vinyl ethers such as 2-methoxyethyl acrylate, 3-methoxyethyl acrylate, 3-methoxyethyl methacrylate, methoxydiethylene glycol acrylate, methoxydiethylene glycol methacrylate, N-acrylamidomethyltrimethylammonium chloride, allyltrimethylammonium chloride, dimethylallyl Examples thereof include vinyl ketone, N-vinylpyrrolidone, vinyl propionate, vinyl stearate, vinyl chloride, vinylidene chloride, vinyl acetate, and styrene.

In the production of the (a) acrylic pressure-sensitive adhesive, there is no particular limitation, but a main monomer, a monomer having a functional group, a polymerization initiator (azobisisobutyronitrile, azobisisobutylene) in an organic solvent. (Valeronitrile, benzoyl peroxide, etc.) are mixed or added dropwise, and polymerization is performed at reflux or at 50 to 90 ° C. for 4 to 20 hours.

The weight-average molecular weight of the obtained acrylic pressure-sensitive adhesive (a) must be 200,000 or more, preferably 200,000 to 1.5 million, more preferably 400,000 to 1,000,000. When the weight average molecular weight is less than 200,000, the pressure-sensitive adhesive composition is unsuitable because it has a disadvantage that the adhesive composition remains on the surface to be adhered upon re-peeling.

The glass transition temperature of (a) the acrylic pressure-sensitive adhesive must be in the range of -60 to -30 ° C, preferably in the range of -55 to -30 ° C. When the glass transition temperature is lower than -60 ° C, the compatibility with the reactant (b) is inferior, and the adhesive strength upon re-peeling after irradiation with ultraviolet rays or radiation is not sufficiently reduced. Remains on the surface to be adhered, and conversely, if the temperature exceeds -30 ° C, a sufficient adhesive strength cannot be obtained, which is inappropriate.

The reaction product of the (b) dimer of a diisocyanate compound and a (meth) acrylate compound used in the present invention is tolylene diisocyanate (TDI), hydrogenated TDI, 4,4'-diphenylmethane diisocyanate (MDI). ), Hydrogenated MDI, crude MDI, modified MD
I, xylylene diisocyanate (XDI), hydrogenated XD
I, tetraxylylene diisocyanate (TMXD
I), isophorone diisophorone (IPDI), norbornene diisophorone (NBDI), dimer of tolylene diisocyanate (TT), hexamethylene diisocyanate (HMDI), trimethylhexamethylene diisocyanate (TMHMDI), o-tolidine diisocyanate (TODI), naphthalene Diisocyanate (ND
I), diphenyl ether diisocyanate (PED)
I), dianisidine diisocyanate (DADI), p
-Phenylene diisocyanate (PPDI), isopropylidenebis-4-cyclohexyl diisocyanate (IPCI), lysine diisocyanate methyl ester (LDI), trimethylhexamethylene diisocyanate (TMDI), dimer acid diisocyanate (DD)
Trimer of diisocyanate compound such as I) and 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-chloro-2 -Hydroxypropyl methacrylate, tetrahydrofurfuryl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, diethylene glycol acrylate, polyethylene glycol acrylate, N-methylol acrylamide, N-methylol methacrylamide, glycidol dimethacrylate, 2-acryloyloxyethyl acid phosphate , Hydroxypropylated trimethylolpropane triacrylate, pentaerythritol Acrylates, is dipentaerythritol pentaacrylate, dipentaerythritol tetraacrylate, a reaction product of an acrylic compound such as tetra-triacrylate or (meth) acrylic acid, as such acrylic compound (meth)
Acrylate compounds are preferred and such reactants include HDI, LDI, XDI, hydrogenated XDI, IP
A combination of a trimer of a diisocyanate compound such as DI and a (meth) acrylate compound having a hydroxyl group is preferred.

The method for producing the reactant (b) is not particularly limited, but a trimer of a diisocyanate compound and an acrylic compound are mixed in an inert gas atmosphere,
The reaction is performed at 100 ° C for 2 to 20 hours. In the reaction, it is preferable to use a urethanization catalyst such as tin octenoate, di-n-butyltin dilaurate, lead octylate, potassium octylate, potassium acetate, stannas octoate, and triethylenediamine.

It is preferable to select the reaction product (b) having a cure shrinkage of 3 to 15%, more preferably 4 to 10%. If the curing shrinkage is less than 3%, the adhesive strength at the time of re-peeling after irradiation with ultraviolet rays or radiation is insufficiently reduced. Conversely, if it exceeds 15%, the pressure-sensitive adhesive after irradiation becomes too hard. When used for temporary bonding in a dicing process of a semiconductor wafer, it is not preferable because expansion cannot be performed or chips are liable to be scattered even if expanded.

The curing shrinkage can be measured by the following method. (B) 4 g of α-hydroxyisobutylphenone was added to and mixed with 100 g of the reaction product, and bubbles were removed.
The specific gravity of the liquid is measured by the specific gravity cup method of JIS K 5400, and the specific gravity at that time is defined as d (g / cm ³ ). Next, a part of the liquid was cylindrically shaped (diameter 5.0 cm, height 1.0 c).
m, an inner volume of 19.6 cm ³ ), poured into a polyethylene mold, irradiated with ultraviolet rays at 500 mJ / cm ² , cured, removed from the mold, and placed in the above specific gravity cup (internal volume 100 cm ³ ). Further, the entire specific gravity cup is weighed by filling with water, the specific gravity s (g / cm ³ ) after curing is determined by the following equation (1), and the curing shrinkage is determined by the following equation (2).

S = a × b / (100a + bc) (1)

## EQU2 ## Curing shrinkage = [(sd) / s)] × 100 (%) (2) [where a: specific gravity of water (g / cm ³ ), b: weight after curing (G): weight of water in specific gravity cup + weight after curing (g), d: specific gravity before curing (g / cm ³ )]

The photopolymerization initiator (c) used in the present invention includes benzoin, isopropyl benzoin ether, isobutyl benzoin ether, benzophenone,
Michler's ketone, chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, acetophenone diethylketal, benzyldimethylketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and the like. Benzylbenzyl ketal, 1-hydroxycyclohexyl phenyl ketone, and 2-hydroxy-2-methyl-1-phenylpropan-1-one are preferred.

The crosslinking agent (d) used in the present invention includes bisphenol A / epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether,
Epoxy compounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl erythritol, diglycerol polyglycidyl ether, tetramethylolmethane-tri-β-aziridinylpropionate, trimethylolpropane-tri-β -Aziridinylpropionate, N, N'-diphenylmethane-4,4'-bis (1-aziridinecarboxamide), N, N'-hexamethylene-1,6-bis (1-aziridinecarboxamide) and the like Aziridine compounds, hexamethoxymethylmelamine, hexaethoxymethylmelamine, hexapropoxymethylmelamine, hexaptoxymethylmelamine, hexapentyloxymethylmelamine, hexahexyloxymethylmethamine Melamine compounds such as lamin, 2,
4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hydrogenated tolylene diisocyanate, 1,
3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4,4-diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, tetramethyl xylylene diisocyanate, 1,5-naphthalene diisocyanate, Tolylene diisocyanate adduct of trimethylolpropane, xylylene diisocyanate adduct of trimethylolpropane, isocyanate compounds such as triphenylmethane triisocyanate, methylenebis (4-phenylmethane) triisocyanate, and the like, among which trimethylolpropane Is preferred.

(A) in the removable pressure-sensitive adhesive composition of the present invention
The amount of each of (a) to (d) is not particularly limited, but the amount of (b) is preferably 5 to 75% by weight based on the total amount of (a) and (b). 70% by weight is preferred. If the amount is less than 5% by weight, the adhesive strength after irradiation with ultraviolet rays or radiation is reduced (removability).
In particular, when the chip is used for temporary bonding in a dicing process of a semiconductor wafer, the chip may be broken if the chip is thin at the time of picking up. Conversely, if the chip exceeds 75% by weight, the adhesive strength is insufficient. In particular, when used for the above applications, the fixing force of a silicon wafer or the like during dicing is too weak, which may cause miscuts or the like, which is not preferable.

The amount of (c) is (a) and (b)
Is preferably 0.1 to 10 parts by weight, more preferably 1.0 to 5.0 parts by weight based on 100 parts by weight of the total amount of If the amount is less than 0.1 part by weight, the decrease in adhesive strength (removability) after irradiation with ultraviolet rays or radiation becomes insufficient, and particularly when the compound is used for temporary bonding in the dicing step of a semiconductor wafer. May be damaged if the chip is thin at the time of pickup.
If the amount exceeds the weight part, (c) the photopolymerization initiator remains on the adhered surface and causes contamination. Particularly, when the photopolymerization initiator is used for temporary bonding in a dicing process of a semiconductor wafer, the photopolymerization initiator is left on the chip. It is not preferable because the agent may remain.

Further, the compounding amounts of (d) are (a) and (b)
Is preferably 0.05 to 10 parts by weight, and more preferably 0.1 to 4% by weight, based on 100 parts by weight of the total amount. When the compounding amount is less than 0.05% by weight, the adhesive composition remains on the adhered surface at the time of re-peeling after irradiation with ultraviolet rays or radiation, causing contamination, and in particular, temporary use in the dicing step of the semiconductor wafer. When used for bonding, the pressure-sensitive adhesive composition may remain on the chip. Conversely, if it exceeds 10% by weight, curing proceeds before irradiation with ultraviolet rays or radiation, and The adhesive strength after irradiation may not be sufficiently reduced, which is not preferable.

As a method for preparing the removable pressure-sensitive adhesive composition of the present invention, the above-mentioned (a) to (d) may be mixed (mixed), and the mixing order and the like are not particularly limited. ,
It is preferable to mix (b) in a solvent and then blend (c) and (d).

The solvents used at this time include (a)
There is no particular limitation as long as it dissolves (d),
Esters such as methyl acetate, ethyl acetate, methyl acetoacetate, and ethyl acetoacetate; ketones such as acetone and methyl isobutyl ketone; aromatic compounds such as toluene and xylene; In view of this, ethyl acetate and toluene are preferably used.

Thus, the removable pressure-sensitive adhesive composition of the present invention can be obtained. However, as long as the effects of the present invention are not impaired, a pressure-sensitive adhesive other than the above (a), urethane resin, rosin, rosin ester, water Rosin ester, phenolic resin, aromatic modified terpene resin, aliphatic petroleum resin,
Known additives for tackifiers such as alicyclic petroleum resins, styrene resins, xylene resins and the like, and compounds which cause coloration or discoloration upon irradiation with ultraviolet rays or radiation can be added.

The removable pressure-sensitive adhesive composition of the present invention is usually applied to a base sheet or the like and is often put to practical use as a pressure-sensitive adhesive sheet or a pressure-sensitive adhesive tape. First, the re-peelable pressure-sensitive adhesive composition of the present invention, as it is or with an appropriate organic solvent, adjusts the concentration, and is applied to the treated surface of the substrate subjected to silicon treatment or the like, or directly to the substrate. Coating, for example, 80 to 105
The adhesive layer can be formed by drying by heat treatment or the like at 30 ° C. for 30 seconds to 10 minutes.

The substrate is not particularly limited as long as it is a film through which ultraviolet rays and the like can pass, and examples thereof include polyvinyl chloride, polybutene, polybutadiene, polyurethane, ethylene-vinyl acetate copolymer, polyethylene terephthalate, polyethylene, and polypropylene. Examples include transparent films such as ethylene-propylene copolymer, polymethylpentene, and polybutylene terephthalate. Particularly, in a dicing process of a semiconductor wafer, when used for an application requiring expansion, polychloride having excellent stretchability at the time of expansion is used. A transparent or ultraviolet-permeable colored film such as vinyl, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, etc. is preferably used.

The removable pressure-sensitive adhesive composition of the present invention is particularly useful for temporary bonding in a dicing step of a semiconductor wafer, and such a usage will be specifically described.

In this application, a semiconductor wafer (silicon wafer) is fixed to a pressure-sensitive adhesive sheet or a pressure-sensitive adhesive tape or the like coated with a removable pressure-sensitive adhesive composition of the present invention on a substrate, and then the rotary round blade is used. To cut the semiconductor wafer into chips. Thereafter, the substrate is cured by irradiating ultraviolet rays or radiation from the substrate side such as an adhesive sheet or an adhesive tape. As a light source for performing ultraviolet irradiation, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light, or the like is used. 5 to 3000 mJ / c for high pressure mercury lamp
m ² , preferably 10 to 500 mJ / cm ² . The irradiation time varies depending on the type of light source, the distance between the light source and the coated surface, the coating thickness, and other conditions, but is usually several seconds, and may be a fraction of a second in some cases. In the case of electron beam irradiation, for example, an electron beam having an energy in the range of 50 to 1000 Kev is used, and the irradiation amount is preferably 2 to 50 Mrad.

Adhesion force before and after curing (JIS Z 0237)
180 degree peel strength) varies depending on the type of the base material and the type of the wafer.
25 mm, 5-30 g / 25 m after irradiation (at the time of re-peeling)
m is preferable. In addition, when the wafer is large and has no expansion, 500 to 1000 g / 25 before curing.
mm, after irradiation (at the time of re-peeling), preferably about 5 to 30 g / 25 mm. When used for temporary surface protection of a metal plate other than a wafer, a glass plate, a plastic plate, etc., about 200 to 900 g / 25 mm before curing, and about 5 to 30 g / 25 mm after irradiation (at the time of re-peeling). Is preferred. Then, after expanding (stretching) the pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape or the like using a wafer expanding device to widen the chip interval, the chips are pushed up with a needle or the like,
The semiconductor chip is picked up by a method of suction with air tweezers or the like, the chip is adhered to the base, and the electrodes are connected by gold wires to form a semiconductor chip as a product. The temporary adhesive application (adhesive sheet for fixing a semiconductor or the like) in the dicing process of a semiconductor wafer has been described above. However, the removable adhesive composition of the present invention is not limited thereto, and may be a metal plate, a glass plate, or the like. It is a very useful removable pressure-sensitive adhesive composition that can be used as a temporary surface protection pressure-sensitive adhesive sheet such as a plastic plate or a silicon wafer.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below.
In the following description, “%” and “parts” are based on weight unless otherwise specified. Example 1 <(a) Acrylic adhesive> A reflux condenser, a stirrer, a dropping funnel and a thermometer were attached to a four-necked round bottom flask, and 74 parts of n-butyl acrylate and 10 parts of methyl methacrylate were added.
Parts, 1.5 parts of acrylic acid, 14.5 parts of 2-hydroxyethyl acrylate and 80 parts of ethyl acetate, and after heating under reflux, 0.07 part of azobisisobutyronitrile was added as a polymerization initiator, and acetic acid was added. After reacting at the ethyl reflux temperature for 3 hours, a solution prepared by dissolving 0.07 part of azobisisobutyronitrile in 5 parts of toluene was added, and the reaction was further conducted at the reflux temperature for 4 hours. 40
%, A weight average molecular weight of 710,000, and an acrylic pressure-sensitive adhesive having a glass transition temperature of -39 ° C. The weight average molecular weight was determined by gel permeation chromatography, and the glass transition temperature was determined by a differential scanning calorimeter (DSC).

<(B) Reaction product of trimer of diisocyanate compound and acrylic compound> A four-necked round bottom flask was equipped with a reflux condenser, a stirrer, a nitrogen gas inlet, and a thermometer. HMD
56 parts of the trimer of I), 20 parts of 2-hydroxypropyl acrylate, 24 parts of dipentaerythritol pentaacrylate, and 0.02 of di-n-butyltin dilaurate
And 0.03 part of hydroquinone monoethyl ether were charged and reacted at 50 ° C. for 7 hours to obtain a reaction product of a trimer of a diisocyanate compound and an acrylic compound. The cure shrinkage of the reaction product was 8.9%.

<Preparation of Removable Adhesive Composition> In a room protected from ultraviolet rays, 30 parts of toluene and 20 parts of the reactant (b) were placed in a 250 ml polyethylene container, and
After dissolution at 0 ° C., 50 parts of the above-mentioned (a) toluene solution of an acrylic pressure-sensitive adhesive (resin content: 40%) and (c) 1.4 parts of 1-hydroxycyclohexylphenyl ketone (Irgacure 184, manufactured by Nippon Ciba Geigy). 55d of tolylene diisocyanate adduct of trimethylolpropane
0.5 part of an ethyl acetate solution (manufactured by Nippon Polyurethane Co., Coronate L-55E) was added and stirred to obtain a uniform solution (removable adhesive composition of the present invention). Using the obtained removable pressure-sensitive adhesive composition, evaluation was performed in the following manner. First, a pressure-sensitive adhesive sheet was prepared in the following manner in order to evaluate the pressure-sensitive adhesive composition. <Production of pressure-sensitive adhesive sheet> In a state where ultraviolet rays are blocked, the re-peelable pressure-sensitive adhesive composition (solution) is coated on a 38 μm-thick polyester film subjected to silicone release treatment so that the thickness after drying becomes 10 μm. Then, it was dried by heating at 100 ° C. for 2 minutes. Then, it was transcribed on an 80 μm polyethylene film as a base material and aged at 40 ° C. for 3 days to produce a pressure-sensitive adhesive sheet.

Using the obtained pressure-sensitive adhesive sheet, the adhesive force, removability, stain resistance, and dicing suitability when used for temporary bonding in a dicing process of a semiconductor wafer, specifically, in the following manner. , Expandability and pickup efficiency were evaluated. (Adhesive strength) In a state where ultraviolet rays are blocked, a silicon wafer, a SUS, and a glass plate are used as adherends, and the 180-degree peel strength (g / 25 mm) before ultraviolet irradiation is determined by JI.
It was measured according to SZ0237. (Removability) Using a silicon wafer, SUS, and a glass plate as adherends, irradiate with ultraviolet rays (2
180 degree peel strength (g / 25) after 50 mJ / cm ² )
mm) was measured according to JIS Z 0237. (Contamination resistance) The above-mentioned adhesive sheet is stuck on each surface of a 4-inch square silicon wafer, SUS, and glass plate to which no foreign matter is attached, and left for 1 hour in a room adjusted to 23 ° C. and 65% RH. After irradiating ultraviolet rays (250 mJ / cm ² with a high-pressure mercury lamp), the adhesive sheet was peeled off from the surface of each adherend, and the surface of each adherend after peeling was measured using a laser surface inspection device. The number of remaining foreign substances having a size of 0.3 μm or more was measured and evaluated as follows. ○ −−− less than 10 pieces △ −−− 10 to less than 30 pieces × −−− 30 or more (suitable for dicing) After sticking the above-mentioned pressure-sensitive adhesive sheet to a semiconductor wafer having a diameter of 5 inches, dicing into a 10 mm square chip shape is performed. Was performed, and the state of the chip at that time was evaluated as follows. ○ −−− No chip scattering is observed △ −−− Chips formed on the edge of the wafer are scattered only × −−− Chips are scattered on the whole

(Suitability for Expanding) After the above dicing, ultraviolet irradiation (same as above) was performed, and the wafer was expanded at an air pressure of 2.0 kg / cm ² using a wafer expansion device. Was observed and evaluated as follows. ○ −−− No chip scattering is observed × −−− Chip scattering is observed (Pickup efficiency) After the above-mentioned expansion, if there is no breakage of the adhesive sheet or chip separation (scattering), use a die bonder. When picking up
The number picked up out of 000 pieces was measured and evaluated as follows. ○ −−− 10000 pieces △ −−− 9995 to 9999 pieces × −−− 9994 pieces or less

Example 2 A peelable pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that (a) the acrylic pressure-sensitive adhesive was changed as follows, and a similar evaluation was performed. <(A) Acrylic pressure-sensitive adhesive> A 4-neck round bottom flask was equipped with a reflux condenser, a stirrer, a dropping funnel and a thermometer, and 85 parts of n-butyl acrylate and 10 parts of methyl methacrylate were added.
, 2.5 parts of acrylic acid, 2.5 parts of 2-hydroxyethyl acrylate and 80 parts of ethyl acetate, and after heating under reflux, 0.07 part of azobisisobutyronitrile was added as a polymerization initiator. After reacting at the ethyl reflux temperature for 7 hours, the reaction mixture was diluted with toluene to obtain an acrylic pressure-sensitive adhesive having a resin content of 40%, a weight average molecular weight of 810,000 and a glass transition temperature of -43 ° C.

Example 3 The procedure of Example 1 was repeated, except that the reactant (b) was changed as follows, to obtain a removable pressure-sensitive adhesive composition, which was similarly evaluated. <(B) Reaction product of trimer of diisocyanate compound and acrylic compound> A four-necked round-bottomed flask was equipped with a reflux condenser,
Attach a stirrer, nitrogen gas inlet and thermometer,
30 parts of hexamethylene diisocyanate (HMDI) trimer, dipentaerythritol pentaacrylate 6
0 parts, 10 parts of pentaerythritol triacrylate,
0.03 parts of stannas octoate and 0.03 parts of hydroquinone monoethyl ether were charged and reacted at 50 ° C. for 7 hours to obtain a reaction product of a trimer of a diisocyanate compound and an acrylic compound. The cure shrinkage of the reaction product is 9.
4%.

Example 4 In the production of the removable pressure-sensitive adhesive composition of Example 1,
(A) Toluene solution of acrylic pressure-sensitive adhesive (resin content 40
%) Was changed to 65 parts, and the amount of the reactant (b) was changed to 14 parts, to obtain a removable pressure-sensitive adhesive composition in the same manner as in Example 1, and similarly evaluated. .

Example 5 In Example 1, (c) 1.4 parts of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, manufactured by Nippon Ciba Geigy) was replaced with 1.4 parts of benzyl methyl ketal (Irgacure 651, manufactured by Nippon Ciba Geigy). 4
Was performed in the same manner as in Example 1 to obtain a removable pressure-sensitive adhesive composition, which was similarly evaluated.

Example 6 Example 1 was repeated except that (d) a 55% ethyl acetate solution of tolylene diisocyanate adduct of trimethylolpropane (Coronate L-55E, manufactured by Nippon Polyurethane Co.) was changed to 1.0 part. The same procedure as in Example 1 was carried out to obtain a removable pressure-sensitive adhesive composition, which was similarly evaluated.

Comparative Example 1 A removable pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that (a) the acrylic pressure-sensitive adhesive was changed as follows, and a similar evaluation was performed. <(A) Acrylic adhesive> A reflux condenser, a stirrer, a dropping funnel and a thermometer were attached to a four-necked round bottom flask, and 64 parts of n-butyl acrylate and 30 parts of methyl methacrylate were added.
Parts, 1 part of acrylic acid, 5 parts of 2-hydroxyethyl methacrylate and 60 parts of ethyl acetate were charged and polymerized in the same manner as in Example 1 to obtain a resin having a resin content of 40%, a weight average molecular weight of 830,000, and a glass transition temperature of -17 ° C. An acrylic adhesive was obtained.

Comparative Example 2 A removable pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that (a) the acrylic pressure-sensitive adhesive was changed as follows, and a similar evaluation was performed. <(A) Acrylic pressure-sensitive adhesive> A reflux condenser, a stirrer, a dropping funnel and a thermometer were attached to a four-neck round bottom flask, and 80 parts of 2-ethylhexyl acrylate, 10 parts of methyl methacrylate, and 2-hydroxy acrylate were used. After charging 10 parts of ethyl and 60 parts of ethyl acetate, starting heating under reflux, adding 0.07 parts of azobisisobutyronitrile as a polymerization initiator, reacting at the reflux temperature of ethyl acetate for 7 hours, and diluting with toluene. Resin content 40%, weight average molecular weight 26
An acrylic pressure-sensitive adhesive having a glass transition temperature of -66 ° C was obtained.

Comparative Example 3 A peelable pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that (a) the acrylic pressure-sensitive adhesive was changed as follows, and a similar evaluation was performed. <(A) Acrylic pressure-sensitive adhesive> A 4-neck round bottom flask was equipped with a reflux condenser, a stirrer, a dropping funnel and a thermometer, and 74 parts of n-butyl acrylate and 10 parts of methyl methacrylate were added.
, 1.5 parts of acrylic acid, 14.5 parts of 2-hydroxyethyl acrylate and 80 parts of toluene, and after heating and refluxing, adding 0.3 parts of azobisisobutyronitrile as a polymerization initiator, and refluxing toluene. After reacting at a temperature for 7 hours, the mixture was diluted with toluene to obtain an acrylic pressure-sensitive adhesive having a resin content of 40%, a weight average molecular weight of 140,000 and a glass transition temperature of -39 ° C.

Comparative Example 4 In the production of the removable pressure-sensitive adhesive composition of Example 1,
(A) The same procedure was performed except that the blending of the acrylic pressure-sensitive adhesive was omitted to obtain a removable pressure-sensitive adhesive composition, which was similarly evaluated.

Comparative Example 5 In the production of the removable pressure-sensitive adhesive composition of Example 1,
The same procedure was performed except that the compounding of the reactant (b) was omitted to obtain a removable pressure-sensitive adhesive composition, which was similarly evaluated. Tables 1 and 2 show the evaluation results of the examples and comparative examples.

[0043]

[Table 1] Adhesive strength (g / 25mm) Removability (g / 25mm) Stain-resistant silicon wafer SUS glass plate Silicon wafer SUS glass plate Silicon wafer SUS glass plate Example 1 525 460 470 11 10 13 ○ ○ ○ 〃 2 700 510 545 10 10 11 ○ ○ ○ ３ 3 505 460 465 9 7 9 ○ ○ ○ 〃 4 630 525 555 13 12 14 ○ ○ ○ ５ 5 525 465 475 10 10 12 ○ ○ ○ 〃 6 420 285 290 13 11 14 ○ ○ ○ Comparative Example 1 30 23 26 14 11 13 ○ ○ ○ 〃 2 530 470 480 185 180 190 × × × 〃 3 540 480 485 40 37 45 × × × ４ 400 0 * * * * * * 〃 5 670 555 580 670 550 575 ○ ＊ ＊ * Adhesion was poor and no subsequent evaluation was performed.

[0044]

[Table 2] Dicing suitability Expandability Pickup efficiency Example 1 ○ ○ ○ 〃 2 ○ ○ ○ 〃 3 ○ ○ ○ 〃 4 ○ ○ ○ 〃 5 ○ ○ ○ 〃 6 ○ ○ ○ Comparative example 1 × * * 〃 2 ○ × 〃 3 △ △ 〃 〃 4 ** ** ** ５ 5 ○ × × * Dicing suitability was poor, and subsequent evaluation was not performed. ** Poor adhesion was not evaluated.

[0045]

The removable pressure-sensitive adhesive composition of the present invention uses a specific acrylic pressure-sensitive adhesive and a specific urethane acrylate compound (adduct), so that the adhesiveness to various adherends, It has excellent re-peelability and post-curing resistance after curing, etc., and especially excellent in dicing suitability, expandability and pickup efficiency when used for temporary bonding in the dicing process of semiconductor wafers. Useful for

Continued on the front page F-term (reference) 4J004 AA10 AA14 AA17 AB01 AB07 CA03 CA04 CA05 CA06 CC02 FA04 FA05 FA08 4J040 DF041 DF042 DF051 DF052 EC022 EC032 EC062 EF181 FA071 FA072 GA05 GA07 GA11 GA12 GA14 GA15 HC22 GA19 HC19 HC13 J KA13 KA16 LA01 LA02 LA06 MA02 MA05 MA10 NA20

Claims (4)

[Claims] 1. (a) having at least one functional group of a carboxyl group, a hydroxyl group, an amide group, a glycidyl group, an amino group and a sulfonic acid group in a molecule, and having a weight average molecular weight of 200,000 or more and a glass transition. An acrylic pressure-sensitive adhesive having a temperature of −60 to −30 ° C., (b) a reaction product of a trimer of a diisocyanate compound and an acrylic compound, (c) a photopolymerization initiator, and (d) a crosslinking agent. A removable pressure-sensitive adhesive composition characterized by the following: 2. The removable pressure-sensitive adhesive composition according to claim 1, wherein the amount of (b) is 5 to 75% by weight based on the total amount of (a) and (b). . 3. The method according to claim 1, wherein the amount of (d) is 0.05 to 10 parts by weight based on 100 parts by weight of the total of (a) and (b). Removable adhesive composition. 4. The removable pressure-sensitive adhesive composition according to claim 1, which is used for a pressure-sensitive adhesive sheet for fixing a semiconductor in a dicing step of a semiconductor wafer.