TWI441889B - A UV-curable releasable adhesive composition, and an adhesive sheet using the same - Google Patents

Description

Ultraviolet-curing re-peelable adhesive composition and adhesive sheet using the same

The present invention relates to a method for protecting a surface of a semiconductor wafer during cutting processing such as formation of an integrated circuit of an IC package and a semiconductor wafer, and for fixing the small piece of the element to be used for maintaining the small piece of the element. A UV-curable re-peelable adhesive composition for use on a temporary fixing adhesive sheet.

In recent years, in the manufacturing process of semiconductors, chipping or cracking which occurs during dicing of wafer thinning is considered to be a more serious problem. For these reasons, it is mainly believed to be caused by the high-speed rotation of the blades during the cutting, which causes the wafers in the cutting to vibrate. The dicing tape used in this type is designed to suppress the vibration of the wafer during dicing, and the adhesive is also required to have a high adhesion and retention.

Among these, for example, an adhesive sheet for wafer adhesion has been disclosed (Patent Document 1), which is composed of a base film and a radiation-curable adhesive layer formed thereon, wherein the radiation The hardening type adhesive layer is composed of a propylene-based adhesive obtained by copolymerizing an acrylate and an OH group-containing polymerizable monomer, and a radiation polymerizable compound having two or more unsaturated bonds, and is radioactive. 20 to 80% by weight of the polymerizable compound has four or more unsaturated bonds, and the elastic modulus after radiation hardening is 1 × 10 ⁹ dyn/cm ² or more. Further, there is an active light-curing type re-peelable adhesive composition (Patent Document 2), which comprises an acrylic resin emulsion adhesive, a polyfunctional (meth) acrylate compound, and an active light curing type surfactant; Further, there is another adhesive resin composition (Patent Document 3) which is a polymer having a weight average molecular weight of 10,000 to 2,000,000, a glass transition temperature of -100 to 100 ° C, and a polymerizable carbon-carbon double bond. An adhesive resin composition of a monomer, a polymerizable carbon-carbon double bond oligomer, and a starter, and which is cured by ultraviolet light, from an ultraviolet curing layer to an ultraviolet curing layer. The adhesion will be less than 1/3.

Furthermore, an adhesive tape for processing a semiconductor substrate formed by using a fluoroacrylate polymer having five or more functional groups is disclosed (Patent Document 4), which is a spherical grid closed by an epoxy resin or the like. Casing tapes for packaging that are used to individualize IC packages, such as Ball Grid Array (BGA) or Chip Size Package (CSP), also require the same considerations, for example, for UV and / Or an adhesive formed of a base resin, a radiation polymerizable compound, a radiation polymerizable polymerization initiator, and a crosslinking agent on the surface of the film having a penetrating electron beam, and further prepared for processing a semiconductor substrate. tape.

Patent Document 1: Patent No. 3410202

Patent Document 2: JP-A-2003-171622

Patent Document 3: JP-A-2006-328160

Patent Document 4: JP-A-2005-50953

An object of the present invention is to provide an ultraviolet curable re-peelable adhesive which is useful as an ultraviolet curable adhesive for forming a film on a wafer or the like, which is useful for cutting tape. In the ideal range in which the strength of the adhesive film before and after curing is reduced, the holding strength is high, and when the cured film is peeled off, the cured film which does not cause a paste remains on the wafer surface.

As a result of the intensive study of the ultraviolet curable re-peelable adhesive, the present inventors have found that an ultraviolet curable re-peelable adhesive can be used to solve the above problems. Containing (a) an acrylic adhesive polymer, (b) a polyfunctional epoxy acrylate, (c) a photopolymerization initiator, and (d) a curing agent reactive with a hydroxyl group, a carboxyl group or an epoxy group, thereby The present invention has been completed.

That is, the present invention relates to an ultraviolet curable re-peelable adhesive composition characterized by (a) an acrylic adhesive polymer, (b) a polyfunctional epoxy acrylate, and (c) light. a polymerization initiator, (d) a curing agent reactive with a hydroxyl group, a carboxyl group or an epoxy group, and (b) a polyfunctional epoxy acrylate comprising any one of the following compounds: a compound represented by the formula (1) ,

[Chemical 1]

(wherein R ¹ is a hydrogen atom or a methyl group which may be the same or different from each other, R ² is a hydrogen atom or a group having an ethylenically unsaturated bond, and X is at least 2 epoxy groups in the molecule. a compound obtained by polymerizing a re-opening ring, wherein R ² is a hydrogen atom, X is a group having at least one ethylenically unsaturated bond, n is an integer) or a compound represented by formula (2),

[Chemical 2]

(wherein R ³ is a hydrogen atom or a methyl group which may be the same or different from each other, and R ⁴ is a hydrogen atom or a methyl group, which may be the same or different from each other, and further, R ⁴ is bonded thereto. The benzene skeleton may be substituted with another substituent, and R ⁵ is a hydrogen atom or a group having an ethylenically unsaturated bond, and at least one of R ⁵ has a group having an ethylenically unsaturated bond, and m is an integer or a formula ( 3) the compound shown,

[Chemical 3]

Wherein R ⁶ is a hydrogen atom or a methyl group which may be the same or different from each other, and R ⁷ is a hydrogen atom or a group having an ethylenically unsaturated bond, and at least one of R ₇ has an ethyl group. The base of the unsaturated bond).

Wherein X is preferably any one of the following: a group represented by formula (4),

[Chemical 4]

(wherein R ⁸ is a hydrogen atom or a methyl group, R ⁹ is a hydrogen atom or a group having an ethylenically unsaturated bond) or a group represented by the formula (5),

[Chemical 5]

(wherein R ¹⁰ is a hydrogen atom or a methyl group, and R ¹¹ is a hydrogen atom or a group having an ethylenically unsaturated bond).

Wherein R ² , R ⁵ , R ⁷ , R ⁹ or R ¹¹ , which are preferably a hydrogen atom or a group represented by the formula (6),

[Chemical 6]

(wherein R ¹² is a hydrogen atom or a methyl group).

In particular, it is preferred to contain (b) a polyfunctional epoxy acrylate in an amount of 20 to 200 parts by mass based on 100 parts by mass of the (a) acrylic adhesive polymer.

Preferably, the (a) acrylic adhesive polymer has a weight average molecular weight of 200,000 to 2,000,000, a glass transition temperature of -50 ° C to 10 ° C, and copolymerization of a (meth) acrylate having a hydroxyl group. The object is made.

Among them, preferred are (b) a reactive product of a polyfunctional epoxy acrylate epoxy acrylate and an α,β-ethylenically unsaturated monoisocyanate.

Furthermore, the present invention relates to an adhesive sheet characterized by using the ultraviolet curable re-peelable adhesive composition described above.

According to the present invention, it is possible to provide an ultraviolet curable re-peelable adhesive which is an ultraviolet-curable adhesive having a film-forming property in forming an integrated circuit such as a wafer, and an adhesive after application. The appearance is excellent, and the holding strength is high in a desired range in which the strength of the adhesive film before and after hardening is useful for the dicing tape, and the cured film formed by ultraviolet irradiation is not peeled off on the wafer surface. A cured film of the paste residue.

The best form of implementing the invention

Hereinafter, the present invention will be specifically described. The (a) acrylic adhesive polymer in the ultraviolet curable re-peelable adhesive composition of the present invention is based on a hardener reactive with (d) a hydroxyl group, a carboxyl group or an epoxy group (hereinafter referred to as (d) Hardener) It is preferred to carry out a crosslinking reaction to increase the cohesive force of the acrylic adhesive polymer, and it is preferred to have a hydroxyl group in the molecule. (a) The acrylic adhesive polymer is specifically a main monomer of an acrylic alkyl ester or a methacrylic alkyl ester, and a copolymer of a hydroxyl group-containing (meth) acrylate. Among them, a monomer having a hydroxyl group, particularly a hydroxyalkyl (meth) acrylate (2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate) is preferred.

The main monomer constituting the (a) acrylic adhesive polymer can be, for example, acrylate (methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, Iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate Ester, stearyl (meth) acrylate, isobornyl (meth) acrylate, etc.), alkyl vinyl ether compound (2-methoxyethyl acrylate, 2-methoxyethyl methacrylate) , 3-methoxyethyl acrylate, 3-methoxyethyl methacrylate, methoxy diethylene glycol acrylate, methoxy diethylene glycol methacrylate).

Further, in the above copolymer, copolymerization with an unsaturated compound (monomer) other than the above may be carried out without departing from the gist of the invention, and such a monomer is preferably an aromatic vinyl compound (benzene). Ethylene, α-methylstyrene, p-methylstyrene, ethylvinylbenzene, etc.), heterocyclic vinyl compound (vinylpyrrolidone, etc.), polyalkylene glycol (meth)acrylate ( Ethylene glycol (meth) acrylate, butane diol (meth) acrylate, etc.), alkylamino (meth) acrylate (N, N-dimethylaminoethyl (meth) acrylate , N,N-dimethylaminopropyl (meth) acrylate, etc.), vinyl ester compound (vinyl formic acid ester, vinyl acetate, vinyl propionate, vinyl versatate), acrylic acid, methacrylic acid .

The copolymerization ratio (mass ratio) of the main monomer and the monomer having a hydroxyl group is preferably 99.9/0.1 to 70/30, and most preferably 99.5/0.5 to 90/10. When the copolymerization is outside this range, when re-peeling, the adhesive composition tends to remain on the surface to be faced.

Further, in the production of the (a) acrylic adhesive polymer, it is not particularly limited, but is preferably in an organic solvent, and the main monomer, the monomer having a hydroxyl group, and the polymerization initiator (azo diiso) It is preferable to mix or drip the nitrile, azobisisovaleronitrile, benzoyl peroxide, etc., and to carry out polymerization for 4 to 20 hours in a reflux state or at 50 to 90 °C.

The (a) acrylic pressure-sensitive adhesive obtained has a weight average molecular weight of 200,000 to 2,000,000, preferably 200,000 to 1,500,000, and most preferably 400,000 to 1,000,000. When the weight average molecular weight is less than 200,000, when it is peeled off again, the adhesive composition tends to remain on the surface.

Further, the glass transition temperature of the (a) acrylic adhesive polymer is preferably -50 to 10 ° C, and most preferably -40 to -15 ° C. (a) When the glass transition temperature of the acrylic adhesive polymer is less than -50 ° C, the compatibility with (b) the polyfunctional epoxy acrylate is poor, and the film is peeled off after irradiation with ultraviolet rays or radiation. Since the adhesive force is not completely lowered, the adhesive composition tends to remain on the surface to be faced. Conversely, if it exceeds 10 ° C, there is a tendency that sufficient adhesion cannot be obtained.

The (b) polyfunctional epoxy acrylate used in the present invention is a denatured epoxy acrylate. That is, it can be obtained by reacting a secondary hydroxyl group in an epoxy acrylate with an α,β-ethylenically unsaturated monoisocyanate.

Epoxy acrylate, which is an epoxy resin and an α,β-unsaturated monovalent acid, for example, acrylic acid and/or methacrylic acid, 50 mol% or more, preferably 80 mol, relative to the epoxy group. % or more, the resin obtained by the conventional method, for example, in "Shoyama Ryuichiro, Handbook of Polyester Resin" (edited by Nikkan Kogyo Shimbun, 1988) or "Dictionary of Coatings" (Edited by Color Materials Association, 1993) The annual report). Further, as described above, the epoxy acrylate has an α,β-unsaturated monovalent acid in an amount of 50 mol% or more, preferably 80 mol% or more, based on the epoxy group of the epoxy resin. The resin obtained by the reaction also contains those having an unreacted epoxy group.

Epoxy resin, for example, bisphenol type (for example, bisphenol, bisphenol A, hydrogenated bisphenol A, bisphenol F, bisphenol S, bisphenol SH, bisphenol Z, 4,4'-dihydroxybenzophenone) , 2,4'-dihydroxybenzophenone, bis(4-hydroxyphenyl)fluorene, catechol, resorcinol, hydroquinone, dihydroxynaphthalene, etc., bisphenols, tetrachlorobisphenol A, etc. ), novolac type (phenol novolac, cresol novolak, bisphenol A novolac, dicyclopentadiene-phenol novolac, etc.), naphthol aralkyl type, phenol aralkyl type, tetraphenyl B An alkyl epoxy resin, a cyclic aliphatic epoxy resin, a triepoxypropyl trimer isocyanate, or a halogen atom such as a bromine atom introduced thereto. Here, in order to completely reduce the adhesive force at the time of re-peeling after irradiation with ultraviolet rays, among them, bisphenol A type, bisphenol F type, hydrogenated bisphenol A type, and phenol novolak type are used. A cresol novolac type epoxy resin or a tri-epoxypropyl trimeric isocyanate is preferred. These epoxy resins may be used alone or in combination of two or more.

The α,β-ethylenically unsaturated monoisocyanate which reacts with the second-order hydroxyl group in the epoxy acrylate, for example, MAI (methacryl oxime isocyanate, manufactured by Nippon Paint Co., Ltd.), Karenz MOI (isocyanate ethyl group) Acrylate, manufactured by Showa Denko Co., Ltd., Karenz AOI (isocyanate ethyl acrylate, manufactured by Showa Denko), Karenz BEI (1,1-bisacryloyloxymethylethyl isocyanate, Showa Denko (share) system). Other polymerizable monoisocyanates, for example, m-TMI (3-isopropenyl-α, α'-dimethylbenzyl isocyanate, manufactured by Amino Cyanide Co., Ltd.) may also be used without departing from the gist of the present invention. Used internally. Among them, based on the viewpoint that the adhesion after ultraviolet curing can be sufficiently reduced, isocyanate ethyl acrylate, isocyanate ethyl methacrylate, 1,1-bispropenyl methoxymethyl ethyl isocyanate good.

The α,β-ethylenically unsaturated monoisocyanate which reacts with the hydroxyl group of the epoxy acrylate in a ratio of 1 mol to 1 mol of the epoxy acrylate, generally α,β-ethylene The monounsaturated monoisocyanate is preferably 0.1 mol or more, preferably 0.3 to 0.9 mol. When the α,β-ethylenically unsaturated monoisocyanate is less than 0.1 mol, the cohesive force is lowered, and the tendency of the adhesive film to remain from the adherend after the adhesive film is removed occurs.

a 2-stage hydroxyl group in an epoxy acrylate and an α,β-ethylenically unsaturated monoisocyanate, the addition reaction may be carried out under the conditions of a general urethanation reaction, and if necessary, dibutyltin may also be used. A urethane catalyst such as dilaurate or diazobiscyclooctane (DABCO) is reacted in the presence or absence of a solvent.

(b) a polyfunctional epoxy acrylate used in the present invention, which may comprise a compound represented by the formula (1),

[Chemistry 7]

(wherein R ¹ is a hydrogen atom or a methyl group which may be the same or different from each other, R ² is a hydrogen atom or a group having an ethylenically unsaturated bond, and X is at least 2 epoxy groups in the molecule. The compound obtained by polymerization reopening, and when R ² is a hydrogen atom, X has at least one ethylenically unsaturated bond group, and n is an integer).

Here, R ² is a hydrogen atom or a group having an ethylenically unsaturated bond, but in all of the polyfunctional epoxy acrylates, R ^{2 is} not necessarily substituted with a group having an ethylenically unsaturated bond, and R ^{2 is} also substituted. It may contain a molecule remaining in the case where the hydrogen atom is not replaced. When R ² is a hydrogen atom, it is obtained by (d) a hardening agent (a) an acrylic adhesive polymer and a crosslinked structure, and it is based on the viewpoint of speeding down the viscosity of the adhesive after ultraviolet irradiation. And ideal.

R ² is a hydrogen atom or a group having an ethylenically unsaturated bond, and is preferably a group represented by the formula (6).

[化8]

(wherein R ¹² is a hydrogen atom or a methyl group). The group represented by the formula (6) can be introduced by reacting an isocyanate ethyl methacrylate or an isocyanate ethyl acrylate with a secondary hydroxyl group in an epoxy acrylate.

In the formula (1), X is a group obtained by polymerizing and reopening a compound having at least two epoxy groups in the molecule, and is preferably any one of the following groups: a group represented by the formula (4).

[Chemistry 9]

(wherein R ⁸ is a hydrogen atom or a methyl group, R ⁹ is a hydrogen atom or a group having an ethylenically unsaturated bond) or a group represented by the formula (5),

[化10]

(wherein R ¹⁰ is a hydrogen atom or a methyl group, and R ¹¹ is a hydrogen atom or a group having an ethylenically unsaturated bond). In order to obtain (b) a polyfunctional epoxy acrylate represented by the formulas (4) and (5), the epoxy resin can be obtained by using bisphenol A, hydrogenated bisphenol A, bisphenol F or the like.

Here, R ⁹ and R ¹¹ are the same as R ² and are a hydrogen atom or a group having an ethylenically unsaturated bond, but in all of the polyfunctional epoxy acrylates, R ⁹ and R ^{11 are} not required. Substitution with a group having an ethylenically unsaturated bond, and R ⁹ and R ¹¹ may also contain a molecule remaining in the case where the hydrogen atom is not replaced.

R ⁹ and R ¹¹ are a hydrogen atom or a group having an ethylenically unsaturated bond, and it is preferred to use a group represented by the above formula (6). The group represented by the formula (6) can be introduced by reacting an isocyanate ethyl methacrylate or an isocyanate ethyl acrylate with a secondary hydroxyl group in an epoxy acrylate.

In the formula (1), n is preferably 1 to 10, and 1 to 5 is most preferred. When n is larger than 10, the compatibility with the acrylic adhesive polymer tends to be inferior.

Further, the (b) polyfunctional epoxy acrylate used in the present invention may further contain a compound represented by the formula (2).

[11]

(wherein R ³ is a hydrogen atom or a methyl group, which may be the same or different from each other, R ⁴ is a hydrogen atom, a methyl group, which may be the same or different from each other, and the benzene skeleton to which R ⁴ is bonded may also be The other substituent is substituted, and R ⁵ is a hydrogen atom or a group having an ethylenically unsaturated bond, and at least one of R ⁵ is a group having an ethylenically unsaturated bond, and m is an integer). In order to obtain the (b) polyfunctional epoxy acrylate represented by the formula (2), the epoxy resin can be obtained by using a phenol novolak type, a cresol novolac type epoxy resin or the like.

Here, at least one of R ⁵ may be a group having an ethylenically unsaturated bond. When R ⁵ is a hydrogen atom, (a) an acrylic adhesive polymer and a crosslinked structure are obtained by (d) a curing agent, and it is based on the viewpoint of speeding up the decrease in adhesion after ultraviolet irradiation. And ideal.

R ⁵ is a group having an ethylenically unsaturated bond, and is preferably a group represented by the above formula (6).

In the formula (2), m is preferably 1 to 10, and 1 to 5 is most preferred. When m is larger than 10, the compatibility with the acrylic adhesive polymer tends to be inferior.

Further, the (b) polyfunctional epoxy acrylate used in the present invention may further contain a compound represented by the formula (3).

[化12]

Wherein R ⁶ is a hydrogen atom or a methyl group, which may be the same or different from each other, and R ⁷ is a hydrogen atom or a group having an ethylenically unsaturated bond, and at least one of R ⁷ has an ethylenicity. The base of the saturated bond). In order to obtain the (b) polyfunctional epoxy acrylate represented by the formula (2), an epoxy resin can be obtained by using tri epoxypropyl trimer isocyanate.

Here, at least one of R ⁷ may be a group having an ethylenically unsaturated bond. When R ⁷ is a hydrogen atom, (a) an acrylic adhesive polymer and a crosslinked structure are obtained by (d) a curing agent, and it is based on the viewpoint of speeding down the viscosity of the adhesive after ultraviolet irradiation. And ideal.

R ⁷ is a group having an ethylenically unsaturated bond, and is preferably a group represented by the above formula (6).

(b) The amount of the polyfunctional epoxy acrylate to be used is generally 20 to 200 parts by mass, preferably 40 to 150 parts by mass, per 100 parts by mass of the (a) acrylic adhesive polymer. (b) When the amount of the polyfunctional epoxy acrylate is less than 20 parts by mass, the three-dimensional network of the adhesive layer by the irradiation of the active light may be incomplete, so that the degree of reduction with respect to the adhesion of the wafer is reduced. It will be too small and not ideal. On the other hand, when the amount is more than 200 parts by mass, the plasticization of the adhesive layer is remarkable, the cohesive force is lowered, and the necessary adhesive force cannot be obtained when the semiconductor wafer is cut, which is not preferable.

In the ultraviolet curable re-peelable adhesive composition of the present invention, if necessary, it may contain (c) a photopolymerization initiator, and active light may be used in the coexistence of (c) photopolymerization initiator. . (c) Photopolymerization initiator used, for example, benzoin isopropyl ether, benzoin isobutyl ether, benzophenone, Michler's ketone, thioxanthone chloride, dodecyl thioxanthene Ketone, dimethyl thioxanthone, diethyl thioxanthone, acetophenone diethyl ketal, benzyl dimethyl ketal, 1-hydroxy-cyclohexyl phenyl ketone, 2-hydroxy-2-methyl Keto-1-phenylpropan-1-one and the like. Among them, benzyl dimethyl ketal, 1-hydroxy-cyclohexyl phenyl ketone, and 2-hydroxy-2-methyl-1-phenylpropan-1-one are particularly excellent in terms of surface hardenability. Preferably.

(c) The amount of the photopolymerization initiator to be used is preferably in the range of 0.1 to 5 parts by mass based on 100 parts by mass of the (b) polyfunctional epoxy acrylate. (c) When the amount of the photopolymerization initiator is less than 0.1 part by mass, the curing speed of the adhesive composition due to irradiation with active light is slowed, and the degree of reduction of the adhesive force is too small. On the other hand, when the amount is more than 5 parts by mass, it is not only impossible to see the effect of matching with it, but the photopolymerization initiator is likely to remain on the surface of the wafer, or the photopolymerization initiator used is used for the photosensitive region. The range becomes larger, and the result of the sensitivity is relatively increased. Amines which can be used are, for example, N,N-dimethylethanolamine, N-methyldiethanolamine and the like. When the amine is used, it is the same amount as the (c) photopolymerization initiator.

Further, the (d) hardener used in the present invention is, for example, 2,4-methylphenylene diisocyanate, 2,6-methylphenylene diisocyanate, hydrogenated phenylene diisocyanate, 1,3- Benzene dimethyl diisocyanate, 1,4-phenylene dimethylene diisocyanate, diphenylmethane-4,4-diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanate methyl) ring Hexane, tetramethylphenyl dimethyl diisocyanate, 1,5-naphthalene diisocyanate, trimethylolpropane, phenylene diisocyanate adduct, trimethylolpropane, phenylene dimethylene Isocyanate compound such as isocyanate adduct, triphenylmethane triisocyanate, methylene bis(4-phenylmethane) triisocyanate, epoxy resin of bisphenol A ‧ epichlorohydrin type, ethylene glycol epoxide Propyl ether, polyethylene glycol diepoxypropyl ether, glycerol diepoxypropyl ether, glycerol triepoxypropyl ether, 1,6-hexanediol diepoxypropyl ether, three Hydroxymethylpropane triepoxypropyl ether, sorbitol polyepoxypropyl ether, polyglycerol polyepoxypropyl ether, pentaerythritol polyepoxypropyl erythritol, diglycerol polycyclic ring An epoxy compound such as oxypropyl ether, tetramethylolmethane-tri-β-azepine propionate, trimethylolpropane-tri-β-azepine propionate, N,N '-Diphenylmethane-4,4'-bis(1-azacyclopropanecarboxyguanamine), N,N'-hexamethylene-1,6-bis(1-azacyclopropanecarboxyguanamine), etc. Aziridine compound, hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxymethyl melamine, hexaethoxyoxymethyl melamine, hexahexyloxy A melamine-based compound such as methyl melamine or the like, and a phenylene diisocyanate adduct of trimethylolpropane, which is preferred from the viewpoint of good reactivity with a propylene-based polymer. (d) A curing agent which is not particularly limited as long as it is reactive with a hydroxyl group, a carboxyl group or an epoxy group, and is not limited to those which react with other functional groups. For example, when the (a) acrylic adhesive polymer has an amine group, the amine group may also react with the (d) hardener.

(d) The amount of the curing agent used is preferably 0.05 to 10 parts by mass, based on 100 parts by mass of the total of (a) the acrylic adhesive polymer and (b) the multifunctional epoxy acrylate. 0.1 to 5 parts by mass is the best. (d) When the amount of the hardener used is less than 0.05 parts by mass, the adhesive composition may remain on the surface to cause contamination when it is peeled off after irradiation with ultraviolet rays or radiation, especially for use in a semiconductor wafer. In the temporary application of the cutting step, there will be a flaw in the adhesive composition remaining on the wafer. Conversely, if it exceeds 10 parts by mass, the curing starts before the irradiation of ultraviolet rays or radiation, and in the ultraviolet or radiation The adhesion after irradiation is lowered, etc., which is not ideal.

In order to form an adhesive sheet using the re-peelable adhesive composition thus constituted, the adhesive composition can be applied to a substrate by a conventional method, and then dried as needed to form a film of generally 10 to 100 μm. It is preferably an adhesive layer having a thickness of about 10 to 50 μm. The substrate is not particularly limited as long as it is a transparent film through which active light is transmitted, and is excellent in elongation when extended. Specifically, polyvinyl chloride, polybutene, and poly can be used. Butadiene, polyurethane, ethylene-vinyl acetate copolymer, polyethylene, polypropylene, ethylene-propylene copolymer, polymethylpentene-1, polyurethane, polyethylene terephthalate A film of a formate or polybutylene terephthalate.

The re-peelable adhesive composition of the present invention is preferably used as an adhesive sheet for a wafer cutting step, but after the semiconductor wafer is attached to the adhesive sheet, the semiconductor wafer is rotated by a rotating blade. The wafer is cut into wafers. Thereafter, the substrate side of the adhesive sheet is irradiated with active light such as ultraviolet rays or electron beams to be hardened.

For the light source for ultraviolet irradiation, a high pressure mercury lamp, an ultrahigh pressure mercury lamp carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black lamp, or the like can be used. In the case of a high-pressure mercury lamp, it is generally carried out under the conditions of an ultraviolet irradiation amount of 50 to 3,000 mJ/cm ² , preferably 100 to 600 mJ/cm ² . For the irradiation of electron beams, for example, an electron beam having an energy in the range of 50 to 1000 KeV can be used, and an irradiation dose of 2 to 50 Mrad is preferable. When the amount of ultraviolet irradiation or the amount of electron beam irradiation is excessive or insufficient, the same condition is unsatisfactory when either or both of the photopolymerization start doses are excessive or insufficient.

The adhesion before and after hardening varies depending on the type of substrate and the type of wafer. However, the 180° peel adhesion force of JIS Z 2307 before curing is 150~2500g/25mm, and the adhesion after irradiation is 5~50g/25mm. The left and right are better. Next, the adhesive sheet is stretched by using a wafer expanding device, and the wafer is stretched to a certain interval, and then the wafer is pushed up by a needle or the like, and the air needle set is provoked by an adsorption method or the like, and the wafer is then transferred. A semiconductor wafer is formed on a substrate and connected by electrodes to form a product.

Example

Hereinafter, the present invention will be specifically described by way of Examples and Comparative Examples, but the present invention is not limited to the examples below. In addition, the "%" and "part" in the following description are based on the definition of quality.

The evaluation of the re-peelable adhesive sheet in the following examples and comparative examples is as follows. The obtained adhesive sheet was attached to the surface of SUS304 using a pressure roller having a weight of 1 kg, and placed in a chamber adjusted to 23 ° C and 65% RH for 1 hour, and then a belt type ultraviolet irradiation device (manufactured by Eyegraphics Co., Ltd.) After the ultraviolet irradiation of 100 mJ/cm ² and 300 mJ/cm ^{2 was} carried out, the change of the adhesion force and the holding force before and after the irradiation was measured in accordance with JIS 0237 by the following method.

(1) Adhesive force: Adhesive tape or adhesive sheet is attached to the test plate or the back surface, and after applying pressure, the force required to peel the adhesive tape or the adhesive sheet at an angle of 180° before and after UV irradiation is measured.

(2) Retention force: At one end of the test plate, the area of the 25 × 25 mm area of the test piece was brought into contact with and attached, and the unattached portion was placed on the inner side and folded. Above the test piece, the roll was pressed back and forth once. After 20 minutes or more, one end of the test plate is stopped with a safety baffle, and then the test plate and the test piece can be vertically suspended, and a weight of 1 kg is terminated at one end of the folded portion. The time from the test plate to the drop of the test tape at a test temperature of 80 ° C was calculated.

(3) Appearance: After applying the adhesive to the substrate and drying it, it was visually confirmed that there was no elastic force, bubbles, foreign matter, or the like on the adhesive layer.

○: Adhesive layer in perfect condition

△: Elastic or sputum is slightly visible

×: Elastomers or sputum are clearly visible

(4) Paste residue: After attaching the adhesive film to the adherend and performing UV irradiation (500 mJ/cm ² ), the adhesive film was peeled off to visually confirm whether or not the adhesive remained on the adherend.

○: no adhesive residue on the adherend

△: Some micro-adhesive residue remains on the adherend

×: There is a significant adhesive residue on the adherend

Production Example 1 <Acrylic Adhesive (1)>

In a reaction apparatus equipped with a stirrer, a temperature regulator, a reflow cooler, a dropping funnel, and a thermometer, 80 parts of n-butyl acrylate, 60 parts of ethyl acrylate, 6.3 parts of methyl methacrylate, 1 part of acrylic acid, and acrylic acid were added. 0.8 parts of 2-hydroxyethyl ester and 130 parts of ethyl acetate, after the start of heating and reflux, 0.1 part of azobisisobutyronitrile as a polymerization initiator was added, and the reaction was carried out for 3 hours at the reflux temperature of ethyl acetate to obtain an azo. 0.1 part of diisobutyronitrile was dissolved in 4 parts of toluene, and then further reacted at a reflux temperature for 4 hours, and diluted with toluene to obtain an acrylic acid having a resin content of 40%, a weight average molecular weight of 550,000, and a glass transition temperature of -35.2 ° C. Adhesive (1). Further, the weight average molecular weight is determined by a gel permeation chromatography method, and the glass transition temperature is determined by a differential scanning calorimeter (DSC).

Production Example 2 <Acrylic Adhesive (2)>

In a reaction device equipped with a stirrer, a temperature regulator, a reflow cooler, a dropping funnel, and a thermometer, 80 parts of n-butyl acrylate, 60 parts of methyl acrylate, 6.3 parts of methyl methacrylate, 1 part of acrylic acid, acrylic acid were added. 0.8 parts of 2-hydroxyethyl ester and 130 parts of ethyl acetate, after the start of heating and reflux, 0.2 parts of azobisisobutyronitrile as a polymerization initiator was added, and the reaction was carried out at a reflux temperature of methyl acetate for 8 hours, and then diluted with toluene. Further, an acrylic pressure-sensitive adhesive (2) having a resin component of 40%, a weight average molecular weight of 610,000, and a glass transition temperature of -25.3 ° C was obtained.

Production Example 3 <Polyfunctional epoxy acrylate (1)>

A bisphenol A type epoxy resin (manufactured by Asahi Kasei Epoxy Co., Ltd., trade name ARALDITE AER 2603, epoxy equivalent 189) was added to a reaction apparatus equipped with a stirrer, a temperature regulator, a reflow cooler, a dropping funnel, and a thermometer. 100 parts (1.0 equivalents), 37 parts of acrylic acid (1.0 moles), 0.6 parts of triphenylphosphine, and 0.12 parts of methylhydroquinone, and the reaction was continued at 120 ° C for 8 hours while blowing air to obtain an acid value of 0.5. KOHmg/g of reactant. Next, the temperature was lowered to 60 ° C, and a mixture of 62 parts of isocyanate ethyl methacrylate (manufactured by Showa Denko Co., Ltd., trade name Karenz MOI) and 0.02 parts of dibutyltin dilaurate was dropped by a dropping funnel. After the completion of the dropwise addition, the reaction system was kept at 70 ° C for 4 hours to remove the isocyanate group, thereby obtaining a polyfunctional epoxy acrylate (1) having a weight average molecular weight of 1300.

Production Example 4 <Multifunctional Epoxy Acrylate (2)>

A cresol novolac type epoxy resin (manufactured by Tohto Kasei Epoxy Co., Ltd., trade name YD-704L, epoxy equivalent) is added to a reaction apparatus equipped with a stirrer, a temperature regulator, a reflow cooler, a dropping funnel, and a thermometer. 209) 100 parts (1.0 equivalent), 33 parts of acrylic acid (1.0 moles), 0.4 parts of triphenylphosphine, and 0.08 parts of methylhydroquinone, and the reaction was continued at 120 ° C for 8 hours while blowing air to obtain an acid. The reactant was priced at 0.5 KOHmg/g. Next, the temperature was lowered to 60 ° C, and a mixture of 56 parts of isocyanate ethyl methacrylate (manufactured by Showa Denko Co., Ltd., trade name Karenz MOI) and 0.02 parts of dibutyltin dilaurate was dropped by a dropping funnel. After the completion of the dropwise addition, the reaction system was kept at 70 ° C for 4 hours to cause the isocyanate group to disappear, thereby obtaining a polyfunctional epoxy acrylate (2) having a weight average molecular weight of 4,000.

Production Example 5 <Multifunctional Epoxy Acrylate (3)>

A trivalent epoxy compound having a triazine core as a skeleton (manufactured by Nissan Chemical Industries, Ltd., trade name TEPIC) is added to a reaction apparatus equipped with a stirrer, a temperature regulator, a reflow cooler, a dropping funnel, and a thermometer. -S, epoxy equivalent 100) 100 parts (1.0 equivalent), 72 parts of acrylic acid (1.0 moles), 0.6 parts of triphenylphosphine, 0.12 parts of methylhydroquinone, and kept at 120 ° C while blowing air The reaction was carried out for 8 hours to obtain a reactant having an acid value of 0.5 KOHmg/g. Next, the temperature was lowered to 60 ° C, and 70 parts of isocyanate ethyl methacrylate (manufactured by Showa Denko Co., Ltd., trade name Karenz MOI) and 0.02 parts of dibutyltin dilaurate were dropped by dropping the funnel. After the completion of the dropwise addition, the reaction system was kept at 70 ° C for 4 hours to remove the isocyanate group, thereby obtaining a polyfunctional epoxy acrylate (3) having a weight average molecular weight of 1,100.

Example 1 <Manufacture of Re-peelable Adhesive and Re-peelable Adhesive Sheet>

In the chamber blocked by ultraviolet light, 70 parts of propylene-based adhesive (1), 30 parts of polyfunctional epoxy acrylate (1), 1-hydroxy-cyclohexyl-phenyl-ketone (steam) were added to the plastic container. Manufactured by Nippon Special Chemicals Co., Ltd., IRGACURE 184), a 45% methyl acetate solution of a methyl phenylene diisocyanate adduct of trimethylolpropane (manufactured by Japan Polyurethane Industrial Co., Ltd., 2.0 parts of CORONET L-45E), stirred and prepared as a re-peelable adhesive, further coated on a polyethylene terephthalate film having a thickness of 50 μm to have a film thickness of 20 μm after drying, and then This was heated and dried at 105 ° C for 2 minutes to prepare a re-peelable adhesive sheet. Then, the change in properties before and after ultraviolet curing was evaluated by the aforementioned method. The measurement results are shown in Table 1.

Example 2

In the production of the re-peelable adhesive sheet of Example 1, except that the amount of the acrylic adhesive (1) used was changed to 60 parts, and the amount of the polyfunctional epoxy acrylate (1) was 40 parts, the remainder was In the same manner as in Example 1, a re-peelable adhesive sheet was produced, and the change in properties before and after ultraviolet curing was evaluated. The measurement results are shown in Table 1.

Example 3

In the production of the re-peelable adhesive sheet of Example 1, except that the amount of the acrylic adhesive (1) used was changed to 50 parts, and the amount of the polyfunctional epoxy acrylate (1) used was 50 parts, the remainder was In the same manner as in Example 1, a re-peelable adhesive sheet was produced, and the change in properties before and after ultraviolet curing was evaluated. The measurement results are shown in Table 1.

Example 4

In the production of the re-peelable adhesive sheet of Example 1, except that the amount of the acrylic adhesive (2) used was changed to 60 parts, and the amount of the polyfunctional epoxy acrylate (1) was 40 parts, the remainder was In the same manner as in Example 1, a re-peelable adhesive sheet was produced, and the change in properties before and after ultraviolet curing was evaluated. The measurement results are shown in Table 1.

Example 5

In the production of the re-peelable adhesive sheet of Example 1, except that the amount of the acrylic adhesive (2) used was changed to 50 parts, and the amount of the polyfunctional epoxy acrylate (1) used was 50 parts, In the same manner as in Example 1, a re-peelable adhesive sheet was produced, and the change in properties before and after ultraviolet curing was evaluated. The measurement results are shown in Table 1.

Example 6

In the production of the re-peelable adhesive sheet of Example 1, except that the amount of the acrylic adhesive (1) used was changed to 70 parts, and the amount of the polyfunctional epoxy acrylate (2) used was 30 parts, the remainder was In the same manner as in Example 1, a re-peelable adhesive sheet was produced, and the change in properties before and after ultraviolet curing was evaluated. The measurement results are shown in Table 1.

Example 7

In the production of the re-peelable adhesive sheet of Example 1, except that the amount of the acrylic adhesive (1) used was changed to 70 parts, and the amount of the polyfunctional epoxy acrylate (3) used was 30 parts, the rest was In the same manner as in Example 1, a re-peelable adhesive sheet was produced, and the change in properties before and after ultraviolet curing was evaluated. The measurement results are shown in Table 1.

Comparative example 1

In the production of the re-peelable adhesive sheet of Example 1, the polyfunctional epoxy acrylate (1) was changed to bisphenol A type epoxy acrylate (manufactured by Showa Polymer Co., Ltd., trade name VR-77). A re-peelable adhesive sheet was produced in the same manner as in Example 1 except that the change in performance before and after ultraviolet curing was evaluated. The measurement results are shown in Table 2.

Comparative example 2

In the manufacture of the re-peelable adhesive sheet of Example 1, except that the amount of the acrylic adhesive (1) used was changed to 60 parts, the polyfunctional epoxy acrylate (1) was changed to bisphenol A type epoxy acrylate. A re-peelable adhesive sheet was produced in the same manner as in Example 1 except for 40 parts, and the change in properties before and after ultraviolet curing was evaluated. The measurement results are shown in Table 2.

Comparative example 3

In the production of the re-peelable adhesive sheet of Example 1, the polyfunctional epoxy acrylate (1) was changed to dipentaerythritol hexaacrylate (Japanese) except that the amount of the acrylic adhesive (1) was changed to 70 parts. A re-peelable adhesive sheet was produced in the same manner as in Example 1 except that 30 parts of the product, manufactured by Kokusai Co., Ltd., and the product name was KAYARAD DPHA, and the change in performance before and after ultraviolet curing was evaluated. The measurement results are shown in Table 2.

Comparative example 4

In the manufacture of the re-peelable adhesive sheet of Example 1, except that the amount of the acrylic adhesive (1) used was changed to 60 parts, the polyfunctional epoxy acrylate (1) was changed to bisphenol A type epoxy acrylate. A re-peelable adhesive sheet was produced in the same manner as in Example 1 except that 20 parts and 20 parts of dipentaerythritol hexaacrylate were used, and the change in performance before and after ultraviolet curing was evaluated. The measurement results are shown in Table 2.

Industrial availability

From the comparison of the examples and the comparative examples, it is understood that the ultraviolet curable re-peelable adhesive composition of the present invention has an excellent appearance of the adhesive layer after application, and has excellent adhesion and retention before ultraviolet irradiation, and is excellent in ultraviolet rays. After the irradiation, a cured film having no paste residue can be obtained.

Claims (6)

An ultraviolet curable re-peelable adhesive composition characterized by (a) an acrylic adhesive polymer, (b) a polyfunctional epoxy acrylate, (c) a photopolymerization initiator, and (d) a reactive product of a reactive hydroxyl group having a hydroxyl group, a carboxyl group or an epoxy group, and (b) a reactive product of a polyfunctional epoxy acrylate epoxy acrylate and an α,β-ethylenically unsaturated monoisocyanate, and the following Any one of the compounds represented by the formula (1), (wherein R ¹ is a hydrogen atom or a methyl group which may be the same or different from each other, R ² is a hydrogen atom or a group having an ethylenically unsaturated bond, and X is at least 2 epoxy groups in the molecule. a compound obtained by polymerizing a re-opening ring, wherein R ² is a hydrogen atom, X is a group having at least one ethylenically unsaturated bond, n is an integer) or a compound represented by formula (2), (wherein R ³ is a hydrogen atom or a methyl group which may be the same or different from each other, and R ⁴ is a hydrogen atom or a methyl group, which may be the same or different from each other, and further, R ⁴ is bonded thereto. The benzene skeleton may be substituted with another substituent, and R ⁵ is a hydrogen atom or a group having an ethylenically unsaturated bond, and at least one of R ⁵ has a group having an ethylenically unsaturated bond, and m is an integer or a formula ( 3) the compound shown, Wherein R ⁶ is a hydrogen atom or a methyl group which may be the same or different from each other, and R ⁷ is a hydrogen atom or a group having an ethylenically unsaturated bond, and at least one of R ⁷ has an ethyl group. The group having an unsaturated bond; the group having an ethylenically unsaturated bond is a group obtained by reacting a 2-stage hydroxyl group of α,β-ethylenically unsaturated monoisocyanate and epoxy acrylate. The ultraviolet curable re-peelable adhesive composition according to claim 1, wherein any one of the X systems is a group represented by the formula (4), (wherein R ⁸ is a hydrogen atom or a methyl group, R ⁹ is a hydrogen atom or a group having an ethylenically unsaturated bond) or a group represented by the formula (5), (wherein R ¹⁰ is a hydrogen atom or a methyl group, R ¹¹ is a hydrogen atom or a group having an ethylenically unsaturated bond); and the group having an ethylenically unsaturated bond of R ⁹ or R ¹¹ is α,β-ethylenic A group obtained by reacting a secondary hydroxyl group of an unsaturated monoisocyanate and an epoxy acrylate. The ultraviolet curable re-peelable adhesive composition according to any one of claims 1 to 2, wherein R ² , R ⁵ , R ⁷ , R ⁹ or R ¹¹ is a hydrogen atom or a formula (6) Base, (wherein R ¹² is a hydrogen atom or a methyl group). The ultraviolet curable re-peelable adhesive composition according to any one of claims 1 to 2, wherein (b) the polyfunctional epoxy is contained in 100 parts by mass of the (a) acrylic adhesive polymer. 20 to 200 parts by mass of acrylate. The ultraviolet curable re-peelable adhesive composition according to any one of claims 1 to 2, wherein (a) the acrylic-based adhesive polymer has a weight average molecular weight of 200,000 to 2,000,000, and a glass transition temperature. It is made up of -50 ° C to 10 ° C and is composed of a (meth) acrylate copolymer having a hydroxyl group. An adhesive sheet characterized by using the ultraviolet curable re-peelable adhesive composition according to any one of claims 1, 2, 3, 4 or 5.