JP2010287884A - Method for manufacturing semiconductor chip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor chip capable of improving an yield of a semiconductor chip by preventing a chip protection film from being damaged during the handling of a wafer, having an excellent cutting characteristic in a dicing process and capable of reducing a warp of the wafer. <P>SOLUTION: In the method for manufacturing a semiconductor chip, a protection film forming sheet including a base material film having a peeling property on one surface and a semiconductor chip protection film formed on one surface having the peeling property and composed of a thermosetting resin composition is stuck to a semiconductor wafer so that the protection film comes into contact with the rear surface of the semiconductor wafer, then the protection film is cured, and then the base material film is peeled off from the cured protection film. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a method for manufacturing a semiconductor chip having a protective film for a wafer for preventing the rear surface of the wafer from being chipped when a semiconductor wafer is diced.

  In order to reduce the mounting area of the semiconductor chip, a flip chip connection method is used. In this connection method, usually, (1) a circuit and connection bumps are formed on the front surface of the semiconductor wafer, (2) the back surface of the semiconductor wafer is polished to a predetermined thickness, and (3) the semiconductor wafer. The semiconductor chip is obtained by dicing, and (4) the circuit forming surface of the chip is connected to the substrate side, and (5) resin sealing or the like is performed to protect the semiconductor chip. It is done.

  However, in the polishing step (2), minute streak-like scratches are formed on the back surface of the chip, which may cause cracks after the dicing step or packaging. Therefore, a protective film (a protective film for a chip) is formed on the back surface after the polishing step (2) so that even if such a streak is generated in the polishing step, the subsequent steps are not adversely affected. Furthermore, as a sheet for forming such a protective film, a sheet comprising a release sheet and a protective film forming layer formed on the release surface is proposed (Patent Document 1, Patent Document). 2).

JP 2002-280329 A JP 2004-260190 A

  On the other hand, in the dicing process, it is known that the wafer may be damaged (hereinafter referred to as “chipping”) due to vibration of the rotary blade or the like.

  The chip protective film is also expected to prevent chipping in the dicing process. However, in order to remove the base film from the uncured chip protective film and handle the chip protective film, Yield decreases when touched and scratched. Further, since the damaged portion is not flat, a gap is generated between the dicing film and the chip protective film, and a portion where the dicing film and the protective film are not in contact is generated. Due to the non-flatness of the protective film, an air layer is generated unevenly between the chip protective film and the dicing film, resulting in a problem that the wafer is further damaged by vibrating the rotary blade when the wafer is cut. is there.

  A wafer to which a protective film for a chip is applied has a semiconductor circuit on the surface opposite to the back surface to which the protective film is applied. The surface further includes a solder ball and a circuit protection layer for protecting the circuit on the chip surface and electrically connecting the circuit and the mounting substrate.

  In general, since the protective film and the circuit protective layer are made of an organic substance, the linear expansion coefficient is larger than that of single crystal silicon constituting the wafer, so that the semiconductor chip is warped in a convex shape when the circuit surface is up. Occurs. This warp generates stress on the wafer, but if the stress is too large, it causes chipping.

  Therefore, an object of the present invention is to solve such a problem and prevent the protective film for chips from being damaged during handling of the wafer, thereby improving the yield, excellent cutting characteristics in the dicing process, and warping of the wafer. It is an object of the present invention to provide a method for manufacturing a semiconductor chip that is reduced.

As a result of the study, as a means for solving the above problems,
A protective film forming sheet having a base film having peelability on one side and a protective film for a semiconductor chip made of a thermosetting resin provided on the peelable single side of the base film, the protective film being a semiconductor Affixed to the back of the wafer,
Next, the protective film is cured,
Next, the base film is peeled from the protective film thus cured.
The manufacturing method of the semiconductor chip including this is provided.

  In the method for manufacturing a semiconductor chip of the present invention, the protective film for a semiconductor chip is cured with the base film attached thereto, so that it is difficult to be damaged during handling before curing, and the yield is improved. Further, the flatness of the protective film is improved, and chipping can be prevented in order to suppress warpage of the semiconductor wafer. Excellent cutting characteristics when dicing.

  Hereinafter, the present invention will be described in more detail. In this specification, “weight average molecular weight” (sometimes abbreviated as Mw) means a polystyrene-reduced weight average molecular weight measured by gel permeation chromatography.

[Composition for protective film formation]
First, the composition used for forming the protective film for a semiconductor chip is not particularly limited as long as it is a thermosetting resin composition, but a phenoxy resin composition, a polyimide resin composition, a (meth) acrylic resin composition, an epoxy. Examples thereof include a resin composition and a maleimide resin composition. These usually contain about 5 to 1500 parts by mass of an inorganic filler such as silica and alumina and a filler such as silicone powder in 100 parts by mass of the resin, and further contain an effective amount of a curing catalyst and / or a curing agent. . The resin, filler, curing catalyst, etc. may be used alone or in combination of two or more.

Particularly preferred thermosetting resin compositions used in the present invention are:
(A) 100 parts by mass of at least one resin selected from the group consisting of phenoxy resin, polyimide resin, and (meth) acrylic resin,
(B) 5 to 200 parts by mass of an epoxy resin,
(C) 10-900 parts by mass of filler, and (D) an effective amount of epoxy resin curing catalyst,
It is a composition containing.

  -(A) Resin selected from phenoxy resin, polyimide resin and (meth) acrylic resin-

・ Phenoxy resin:
The phenoxy resin is a resin derived from epichlorohydrin and bisphenol A or bisphenol resin F or the like. Preferably, the weight average molecular weight in terms of polystyrene is 10,000 to 200,000, more preferably 20,000 to 100,000, and most preferably 30,000 to 80,000. When the weight average molecular weight is less than the lower limit, it is difficult to form a film, whereas when the weight average molecular weight is larger than the upper limit, the gap is filled following the unevenness of the substrate surface having a fine circuit pattern. It is difficult to get enough softness.

  Examples of the phenoxy resin include those sold under the trade names PKHC, PKHH, and PKHJ (all manufactured by Sakai Chemical Co., Ltd.), and the commercial names Epicoat 4250, Epicoat 4275, and Epicoat 1255HX30 of bisphenol A and bisphenol F mixed types. (All manufactured by Nippon Kayaku Co., Ltd.), Epicoat 5580BPX40 (all manufactured by Nippon Kayaku Co., Ltd.) using brominated epoxy, bisphenol A type trade names YP-50, YP-50S, YP-55, YP -70 (all manufactured by Tohto Kasei Co., Ltd.), and those sold under the trade names JER E1256, E4250, E4275, YX6954BH30, YL7290BH30 (all manufactured by Japan Epoxy Resin). JER E1256 is preferably used in that it has the above preferred weight average molecular weight. The phenoxy polymer has an epoxy group at the end, which reacts with the component (B) described later.

  The phenoxy resin can be used alone or in combination of two or more.

・ Polyimide resin:
As a polyimide resin, what contains the repeating unit represented by following formula (1) can be used.

(In the formula, X is a tetravalent organic group containing an aromatic ring or an aliphatic ring, Y is a divalent organic group, and q is an integer of 1 to 300.)

  The polyimide resin preferably has a weight average molecular weight of 10,000 to 200,000, more preferably 20,000 to 100,000, and most preferably 30,000 to 80,000. When the weight average molecular weight is less than the lower limit, it is difficult to form a film, whereas when the weight average molecular weight is larger than the upper limit, the gap is filled following the unevenness of the substrate surface having a fine circuit pattern. It is difficult to get enough softness.

  The said polyimide silicone resin can be obtained by dehydrating and ring-closing the polyamic acid resin which has a repeating unit represented by following formula (2) by a conventional method.

(2)
(Wherein X, Y and q are as defined above.)

  The polyamic acid resin represented by the above formula is represented by the following formula (3):

(However, X has the same meaning as described above.)
A tetracarboxylic dianhydride represented by the following formula (4)
_{H 2 N-Y-NH 2} (4)
(However, Y has the same meaning as described above.)
Can be obtained by reacting in a substantially equimolar amount in an organic solvent according to a conventional method.

  Here, the following are mentioned as an example of the tetracarboxylic dianhydride represented by the said Formula (3), These may be used individually by 1 type or in combination of 2 or more types.

  Among the diamines represented by the above formula (4), the organic solvent is preferably 1 to 80 mol%, more preferably 1 to 60 mol% is a diaminosiloxane compound represented by the following formula (5). It is desirable from the viewpoint of solubility in water, adhesion to a substrate, low elasticity, and flexibility.

(In the formula, R ¹ is a divalent organic group having 3 to 9 carbon atoms, independently of each other, and R ² and R ³ are each independently a monovalent group having 1 to 8 carbon atoms, which is unsubstituted or substituted. A hydrocarbon group, and m is an integer of 1 to 200.)

The divalent organic group of the carbon atoms 3-9, for _{example, - (CH 2) 3 -} , - (CH 2) 4 -, - CH 2 CH (CH 3) -, - (CH 2) 6 Alkylene groups such as — and — (CH ₂ ) ₈ —,

An arylene group, an alkylene / arylene group, an oxyalkylene group such as — (CH ₂ ) ₃ —O— or — (CH ₂ ) ₄ —O—, represented by the following formula:

An oxyarylene group represented by any of the following formulae

And a divalent hydrocarbon group which may contain an ether bond, such as an oxyalkylene / arylene group represented by the formula:

Examples of the unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms represented by R ² and R ³ include, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert. -Alkyl groups such as butyl group, hexyl group, cyclohexyl group, 2-ethylhexyl group, octyl group, allyl group, propenyl group, isopropenyl group, alkenyl group such as butenyl group, isobutenyl group, hexenyl group, phenyl group, tolyl group , Aryl groups such as xylyl groups, aralkyl groups such as benzyl groups and phenylethyl groups, and some or all of the hydrogen atoms bonded to carbon atoms of these hydrocarbon groups are substituted with halogen atoms such as fluorine, bromine and chlorine Group, for example, halogen-substituted alkyl such as chloromethyl group, bromoethyl group, 3,3,3-trifluoropropyl group, etc. Groups and the like, and among them, a methyl group and a phenyl group are preferable.

  The diaminosiloxane compound of the formula (5) can be used alone or in combination of two or more.

  Examples of the diamine represented by the above formula (4) other than the diaminosiloxane compound represented by the above formula (5) include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, and 4,4. '-Diaminodiphenyl ether, 2,2'-bis (4-aminophenyl) propane, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (p-aminophenylsulfonyl) benzene, 1,4-bis (m-aminophenylsulfonyl) benzene, 1,4-bis (p-amino) Phenylthioether) benzene, 1,4-bis (m-aminophenylthioether) benzene, 2,2- [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3-methyl-4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3-chloro-4- (4) -Aminophenoxy) phenyl] propane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,1-bis [3-methyl-4- (4-aminophenoxy) phenyl] ethane, 1, 1-bis [3-chloro-4- (4-aminophenoxy) phenyl] ethane, 1,1-bis [3,5-dimethyl-4- (4-aminophenoxy) phenyl] ethane, bis [4- (4 -Aminophenoxy) phenyl] methane, bis [3-methyl-4- (4-aminophenoxy) phenyl] methane, bis [3-chloro-4- (4-aminophenoxy) phenyl] methane, bi [3,5-dimethyl-4- (4-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] per Examples thereof include aromatic ring-containing diamines such as fluoropropane, and preferably p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 1,4-bis (3- Aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3-methyl-4- (4) -Aminophenoxy) phenyl] propane and the like.

  Preferably, the polyimide resin has a phenolic hydroxyl group from the viewpoint of adhesiveness of the protective film. The phenolic hydroxyl group can be prepared by using a diamine compound having a phenolic hydroxyl group. Examples of such a diamine include those having a structure represented by the following formula (6). It is done.

  The representative group of B is a group represented by the following formula.

(Wherein R ^{4 s} are independently of each other a hydrogen atom; a halogen atom such as fluorine, bromine or iodine; or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and each aromatic ring Substituents attached to may be different, and n is an integer of 0 to 5. A and B may be one kind or a combination of two or more kinds, and R is independently a hydrogen atom or a halogen atom. Or an unsubstituted or substituted monovalent hydrocarbon group.)

Examples of the unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms include those exemplified above for R ² and R ³ , and alkynyl groups such as ethynyl group, propynyl group, butynyl group, and hexynyl group. Etc.

  Moreover, what is represented by Formula (7) is mentioned as diamine which has another phenolic hydroxyl group.

(In the above formula, R is a hydrogen atom, a halogen atom such as fluorine, bromine or iodine, or an unsubstituted alkyl group, alkenyl group, alkynyl group, trifluoromethyl group, phenyl group or the like having 1 to 8 carbon atoms. Or a halogen-substituted monovalent hydrocarbon group, the substituents attached to each aromatic ring may be different, and X is a single bond, a methylene group, or a propylene group.)

  Among the diamine compounds having a phenolic hydroxyl group, a diamine compound represented by the following formula (8) is preferable among those represented by the formula (6).

(Wherein R ⁴ is as defined above.)

  As a compounding quantity of the diamine compound which has the said phenolic hydroxyl group, it is preferable that it is 5-60 mass% of the whole diamine compound, and it is especially 10-40 mass%. When a polyimide silicone resin having a blending amount in this range is used, a high adhesive force and a flexible adhesive layer can be formed.

  In addition, the monoamine which has a phenolic hydroxyl group can also be used for introduction | transduction of a phenolic hydroxyl group, The monoamine which has the following structure is mentioned as the example.

(Where D is

The indicated, R ⁴ is as defined above, R ⁴ attached to the each aromatic ring may be the same or different. D may be used alone or in combination of two or more. P is an integer of 1 to 3. )

  When a monoamine having a phenolic hydroxyl group is used, the blending amount is 1 to 10 mol% with respect to the entire diamine compound.

  The polyamic acid resin can be synthesized by dissolving the above starting materials in a solvent under an inert atmosphere and reacting them usually at 80 ° C. or lower, preferably 0 to 40 ° C. The obtained polyamic acid resin is usually heated to 100 to 200 ° C., preferably 150 to 200 ° C., thereby dehydrating and ring-closing the acid amide portion of the polyamic acid resin to synthesize the target polyimide resin. it can.

  The solvent may not be one that can completely dissolve the starting material as long as it is inert to the resulting polyamic acid. Examples include tetrahydrofuran, 1,4-dioxane, cyclopentanone, cyclohexanone, γ-butyrolactone, N-methylpyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide and dimethyl sulfoxide, preferably aprotic Polar solvents, particularly preferably N-methylpyrrolidone, cyclohexanone and γ-butyrolactone. These solvents can be used singly or in combination of two or more.

  In order to facilitate the dehydration ring closure, it is desirable to use an azeotropic dehydrating agent such as toluene or xylene. Further, dehydration ring closure can be performed at a low temperature using an acetic anhydride / pyridine mixed solution.

  In order to adjust the molecular weight of the polyamic acid and polyimide resin, dicarboxylic anhydrides such as maleic anhydride and phthalic anhydride and / or aniline, n-butylamine, monoamines having the above-mentioned phenolic hydroxyl groups are polyamic. It can also be added in the synthesis of the acid. However, the addition amount of dicarboxylic anhydride is usually 0 to 2 parts by mass per 100 parts by mass of tetracarboxylic dianhydride, and the addition amount of monoamine is usually 0 to 2 parts by mass per 100 parts by mass of diamine. Part.

-(Meth) acrylic resin (Meth) acrylic resin is derived from, for example, two or more monomers selected from (meth) acrylic acid, (meth) acrylic acid ester monomers, and other derivatives of (meth) acrylic acid. (Meth) acrylic acid ester copolymer is mentioned. Here, the (meth) acrylic acid ester monomer is preferably a (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl group, such as methyl (meth) acrylate, ethyl (meth) acrylate, ( For example, propyl (meth) acrylate and butyl (meth) acrylate are used. Examples of other derivatives of (meth) acrylic acid include glycidyl (meth) acrylate and hydroxyethyl (meth) acrylate.

  When a glycidyl group is introduced into a (meth) acrylic resin by copolymerizing glycidyl methacrylate or the like as a comonomer, compatibility with an epoxy resin as a thermosetting adhesive component, which will be described later, is improved. Tg is increased and heat resistance is improved. Further, by introducing a hydroxyl group into the acrylic polymer with hydroxyethyl acrylate or the like, it becomes easy to control the adhesion of the protective film to the semiconductor chip and the physical properties of the adhesive.

  The weight average molecular weight of the (meth) acrylic resin is preferably 100,000 or more, more preferably 150,000 to 1,000,000. The glass transition temperature of the (meth) acrylic resin is preferably 20 ° C. or less, more preferably about −70 to 0 ° C., and has adhesiveness at room temperature (23 ° C.).

-(B) Epoxy resin-
The epoxy resin used as the component (B) in the present invention is a compound having at least two epoxy groups in the molecule. In particular, the epoxy equivalent is preferably 50 to 5000 g / eq, more preferably 100 to 500 g / eq.

  The epoxy resin has a weight average molecular weight of usually less than 10,000, preferably 400 to 9000, more preferably 500 to 8000.

  Such epoxy resins include, for example, bis (4-hydroxyphenyl) methane, 2,2′-bis (4-hydroxyphenyl) propane, or diglycidyl ethers of these halides; Polymers (so-called bisphenol F type epoxy resin, bisphenol A type epoxy resin, etc.); butadiene diepoxide; vinylcyclohexene dioxide; diglycidyl ether of resorcin; 1,4-bis (2,3-epoxypropoxy) benzene; 4′-bis (2,3-epoxypropoxy) diphenyl ether; 1,4-bis (2,3-epoxypropoxy) cyclohexene; bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate; 1,2-dihydroxy Benzene, resorcinol, etc. Epoxy glycidyl ether or polyglycidyl ester obtained by condensing polyhydric phenol or polyhydric alcohol and epichlorohydrin; condensing novolac-type phenol resin (or halogenated novolac-type phenol resin) such as phenol novolak and cresol novolak with epichlorohydrin Epoxy novolak (ie, novolak type epoxy resin) obtained by epoxidation, epoxidized polyolefin, epoxidized polybutadiene; naphthalene ring-containing epoxy resin; biphenyl type epoxy resin; phenol aralkyl type epoxy resin; biphenyl aralkyl type Epoxy resin; cyclopentadiene type epoxy resin and the like.

  Among these, bisphenol F type epoxy resin and bisphenol A type epoxy resin that are liquid at room temperature are preferable as the component (B).

  These epoxy resins can be used alone or in combination of two or more.

  (B) The compounding quantity of the epoxy resin of a component is 5-200 mass parts with respect to 100 mass parts of resin of (A) component, It is preferable that it is especially 10-100 mass parts. If the amount of the epoxy resin is too small, the adhesive strength of the adhesive composition may be inferior, and if it is too large, the flexibility of the adhesive layer may be insufficient.

-(C) Filler-
As the filler, an inorganic filler, for example, conductive particles such as silica, alumina, titanium oxide, carbon black, silver particles, or silicone resin powder can be used. Examples of the silicone resin powder include a crosslinked spherical dimethylpolysiloxane fine powder having a structure in which dimethylpolysiloxane is crosslinked (Japanese Patent Laid-Open No. 3-93934), and a crosslinked spherical polymethylsilsesquioxane fine powder (Japanese Patent Laid-Open No. 3-47848), fine powder (JP-A-7-196815, JP-A-9-20631) obtained by coating the surface of a crosslinked spherical polysiloxane rubber with a polymethylsilsesquioxane resin (hereinafter referred to as JP-A-9-20631) And silicone rubber fine particles coated with polymethylsilsesquioxane resin).

  The blending amount of the filler is 10 to 900 parts by weight, preferably 100 to 400 parts by weight, more preferably 150 to 350 parts by weight, and particularly preferably 150 to 300 parts by weight with respect to 100 parts by weight of the component (A). It is. If the blending amount is too small, it may be difficult to achieve low water absorption, low linear expansion, etc., which are blending purposes of the filler. On the other hand, when too large, the viscosity of the composition for forming a protective film is increased, and the fluidity when applied to a film substrate may be deteriorated.

  (C) Of the filler, 10 to 100 parts by mass, preferably 20 to 70 parts by mass, are preferably silicone rubber fine particles coated with a polyorganosilsesquioxane resin.

  By including the silicone rubber fine particles coated with such a polyorganosilsesquioxane resin, the cutting property of the protective film is remarkably improved. If the amount is less than the lower limit, it is difficult to improve the cutting property of the chipping protective film during dicing. On the other hand, when the upper limit is exceeded, the viscosity of the composition for forming a protective film becomes too high, and the fluidity of the composition when applied to a film substrate is deteriorated. In addition, the adhesive strength of the protective film to the wafer becomes poor, and a higher temperature is required when the protective film is attached to the wafer, and peeling from the wafer is likely to occur, which may reduce the reliability as the protective film.

  Silicone rubber fine particles whose surface is coated with a polyorganosilsesquioxane resin can be produced by the method described in the above-mentioned publications (Japanese Patent Application Laid-Open Nos. 7-196815 and 9-20631). Moreover, silicone composite powders, for example, those commercially available as trade name KMP600 series (manufactured by Shin-Etsu Chemical Co., Ltd.) can be used.

  The filler other than the silicone rubber fine particles whose surface is coated with the polyorganosilsesquioxane resin as the filler of the component (C) is preferably an inorganic filler, more preferably silica. As silica, for example, silica produced by a deflagration method, fused silica, or crystalline silica is preferably used. The average particle diameter of silica is preferably 0.1 to 10 μm, and more preferably 0.5 to 7 μm. When the average particle diameter of silica is within this range, good smoothness of the surface of the applied adhesive layer can be obtained. Further, in recent years, the thickness of the adhesive layer is often required to be 15 to 50 μm. If the average particle diameter of the silica is within the above range, this requirement is present even if secondary agglomerated particles exist. Easy to meet. Silica produced by the deflagration method is most preferred, and spherical silica produced by the deflagration method is particularly preferred.

  Silica is easily wetted by the resin component and may be surface-treated according to a conventional method. As the surface treatment agent, a silane (silane coupling agent) is preferable because of its versatility and cost merit. As the silane coupling agent, the alkoxysilane includes glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, α-glycidoxyethyltrimethoxysilane, α-glycidoxyethyltriethoxysilane, β- Glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, α-glycidoxypropyltrimethoxysilane, α-glycidoxypropyltriethoxysilane, β-glycidoxypropyltrimethoxysilane, β- Glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, α-glycidoxybutyltrimethoxysilane, α-glycidoxybutyltriethoxysilane, β -Glycidoxybutyl Limethoxysilane, β-glycidoxybutyltriethoxysilane, γ-glycidoxybutyltrimethoxysilane, γ-glycidoxybutyltriethoxysilane, δ-glycidoxybutyltrimethoxysilane, δ-glycidoxybutyl Triethoxysilane, (3,4-epoxycyclohexyl) methyltrimethoxysilane, (3,4-epoxycyclohexyl) methyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3, 4-epoxycyclohexyl) ethyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltripropoxysilane, β- (3,4-epoxycyclohexyl) ethyltributoxysilane, β- (3,4-epoxycyclohexyl) Ethyltriphenoxysilane, -(3,4-epoxycyclohexyl) propyltrimethoxysilane, γ- (3,4-epoxycyclohexyl) propyltriethoxysilane, δ- (3,4-epoxycyclohexyl) butyltrimethoxysilane, δ- (3,4, -Epoxycyclohexyl) trialkoxysilane such as butyltrimethoxysilane, N-β- (aminoethyl) γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) γ-aminopropylmethyldiethoxysilane, γ-amino Propyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, trimethoxysilylpropyl nadic acid anhydride, etc., γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane are preferably used.

-(D) Epoxy resin curing catalyst-
Examples of the epoxy resin curing catalyst (D) include phosphorus catalysts and amine catalysts.

  Examples of the phosphorus catalyst include triphenylphosphine, triphenylphosphonium triphenylborate, tetraphenylphosphonium tetraphenylborate, and a compound represented by the following formula.

(Wherein R ^{8 to} R ¹⁵ are each independently a halogen atom such as a hydrogen atom, fluorine, bromine or iodine, or an alkyl having 1 to 8 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group. A alkenyl group having 2 to 8 carbon atoms such as a group, a vinyl group or an allyl group, an alkynyl group having 2 to 8 carbon atoms such as a propynyl group or a butynyl group, a 6 to 8 carbon atom such as a phenyl group or a toluyl group. Monovalent unsubstituted hydrocarbon groups such as aryl groups, and substituted carbons such as trifluoromethyl groups in which at least a part of the hydrogen atoms of these hydrocarbon groups are substituted with halogen atoms such as fluorine, bromine and iodine And a hydrocarbon group substituted with an alkoxy group having 1 to 8 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, etc. In the substituted monovalent hydrocarbon group All of the substituents may be different each be the same.

  Specific examples of particularly preferred phosphorus catalysts are triphenylphosphine, triphenylphosphonium triphenylborate, tetraphenylphosphonium tetraphenylborate and the like.

  Examples of the amine catalyst include imidazole derivatives such as dicyandiamide, 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-methylimidazole, and 2-phenyl-4,5-dihydroxymethylimidazole. Can be mentioned. Among these, dicyandiamide and 2-phenyl-4,5-dihydroxymethylimidazole are preferable.

  (D) As a catalyst of a component, the catalyst mentioned above can be used individually by 1 type or in mixture of 2 or more types. Particular preference is given to using dicyandiamide.

  (D) The compounding quantity of the epoxy resin curing catalyst of a component is an effective amount, and is specifically 5-50 mass parts per 100 mass parts of resin of (A) component.

-Other optional components-
The composition for forming a protective film used in the present invention can contain other components and various additives as necessary in addition to the components described above.

-Monoepoxy compound In addition to the epoxy resin (having two or more epoxy groups) as the component (B), the monoepoxy compound may be blended in an amount that does not impair the object of the present invention. For example, examples of the monoepoxy compound include styrene oxide, cyclohexene oxide, propylene oxide, methyl glycidyl ether, ethyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, octylene oxide, and dodecene oxide.

・ Epoxy resin curing agent:
Although the curing agent is not essential, the addition of the curing agent makes it possible to control the resin matrix, and can expect effects such as a low linear expansion coefficient, a high Tg, and a low elastic modulus.

As this curing agent, conventionally known various curing agents for epoxy resins can be used. For example, diethylenetriamine, triethylenetetramine, diethylaminopropylamine, N-aminoethylpiperazine, bis (4-amino-3-methylcyclohexyl) methane, metaxylylenediamine, menthanediamine, 3,9-bis (3-aminopropyl) -Amine compounds such as 2,4,8,10-tetraoxaspiro [5.5] undecane; epoxy resins-modified aliphatic polyamines such as diethylenetriamine adduct, amine-ethylene oxide adduct, cyanoethylated polyamine; bisphenol A, tri Methylol allyloxyphenol, low polymerization degree phenol novolac resin, epoxidized or butylated phenol resin, “Super Becksite” 1001 [manufactured by Nippon Reichhold Chemical Co., Ltd.], “ Hitanol "4010 (manufactured by Hitachi, Ltd.), Scadoform L. Phenol resin containing at least two phenolic hydroxyl groups in the molecule known under the trade name such as 9 (manufactured by Scado Zwoll, The Netherlands), Methylon 75108 (manufactured by General Electric, USA); “Beckamine” P. 138 [manufactured by Nippon Reichhold Chemical Co., Ltd.], “Melan” [manufactured by Hitachi, Ltd.], “U-Van” 10R [manufactured by Toyo Kodan Kogyo Co., Ltd.], etc. resin; formula _{HS (C 2 H 4 OCH 2} OC 2 H 4 SS) n C 2 H 4 OCH 2 OC 2 H 4 SH (n = 1~10 integer); melamine resins, amino resins such as aniline resins Polysulfide resin having at least two mercapto groups in one molecule; phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, pyromellitic anhydride, methyl nadic acid, dodecyl succinic anhydride, chlorendic anhydride Examples thereof include organic acids such as acids or anhydrides (acid anhydrides) thereof.

  Among the curing agents described above, phenolic resins (particularly phenol novolac resins) give good molding workability to the protective film-forming composition used in the present invention, give excellent moisture resistance, and are toxic. It is desirable because it is relatively inexpensive.

  The above-mentioned curing agents may be used alone or in combination of two or more according to the curing performance of each curing agent.

  The amount of the curing agent is appropriately adjusted according to the type of the curing agent as long as the reaction between the phenoxy resin as the component (A) and the epoxy resin as the component (B) is not disturbed. Generally, it is used in the range of 1 to 100 parts by mass, preferably 5 to 50 parts by mass with respect to 100 parts by mass of the epoxy resin. When the amount exceeds 100 parts by mass, it is economically disadvantageous, and the epoxy resin is diluted so that it takes a long time to cure, and further, there may be a disadvantage that the physical properties of the cured product are lowered.

·solvent:
If necessary, a solvent such as cyclohexanone, MIBK, MEK or the like can be used for the composition, and other components can be dissolved or dispersed to improve the coating property.

・ Other additives:
In the composition for forming a protective film used in the present invention, a colorant such as an inorganic or organic pigment or dye, a silane coupling agent, an antioxidant, or a flame retardant, as long as the effects of the present invention are not impaired. Further, an antistatic agent, a heat stabilizer and the like can be added. For example, when a protective film is colored by blending pigments, dyes, etc., visibility and optical device recognition performance are improved when a laser mark or the like is engraved.

  The protective film is a known method such as a gravure coater so that the protective film forming composition obtained by mixing the above components on the base film has a thickness after drying of 5 to 100 μm, preferably 10 to 60 μm. It can be obtained by applying.

[Base film]
As the base film, a heat resistant film is preferable, and examples of a film having excellent heat resistance include a polyethylene terephthalate film, a polyimide film, a fluororesin film, and the like.

  The base film needs to have peelability on one side. In this specification, such a base film having peelability on one side may be referred to as a “release sheet”. Although some of the fluororesin film itself has releasability without being subjected to a mold release treatment, it is generally preferable to perform a mold release treatment on the surface of the substrate film to impart the releasability. Specifically, it can be applied by coating a release agent and providing a release agent layer. As the release agent, a silicone resin release agent and an alkyd resin release agent are preferable. Preferably, it is a polyethylene terephthalate film coated with a release agent and provided with a release agent layer.

  The film thickness of the substrate is about 5 to 200 μm, preferably about 10 to 150 μm, and particularly preferably about 20 to 100 μm.

  The average thickness of the release agent layer in the dry state is not particularly limited, but is preferably 0.01 to 10 μm, and more preferably 0.03 to 0.3 μm. When the average thickness of the release agent layer exceeds the upper limit, when the release sheet is wound up in a roll shape, the surface of the release agent layer and the back surface of the release sheet come into contact with each other, and both are likely to be blocked. The peeling performance of the film may be reduced by this blocking.

  Conventionally known silicone resin release agents and alkyd resin release agents can be used.

  As the silicone resin release agent, an addition reaction curable type having dimethylpolysiloxane as a basic skeleton is preferable. Further, it is more preferable that no non-functional long-chain silicone oil or silicone rubber is contained.

  The alkyd resin release agent is mainly composed of a polybasic acid and a polycondensation product (alkyd resin) of a polyhydric alcohol, and includes a thermosetting alkyd resin modified with a modifier. Examples of the polybasic acid include aromatic polybasic acids such as phthalic anhydride and terephthalic acid, and aliphatic polybasic acids such as succinic acid, adipic acid, maleic acid, maleic anhydride, and fumaric acid. Examples of the polyhydric alcohol include dihydric alcohols such as ethylene glycol, diethylene glycol, and propylene glycol, trihydric alcohols such as glycerin and trimethylolpropane, and polyhydric alcohols such as pentaerythritol, dipentaerythritol, and sorbitol. Examples of the modifier include stearic acid, oleic acid, linoleic acid and the like.

  1000-80000 is preferable and, as for the weight average molecular weight of alkyd resin, 3000-20000 is especially preferable.

More specifically, the method of the present invention is carried out, for example, as follows to manufacture a semiconductor chip.
(1) A step of attaching a protective film side of a protective film forming sheet comprising a base film and a protective film to the back surface of a semiconductor wafer having a circuit formed on the front (front) surface;
(2) A step of curing the protective film by heating with the base film attached to the protective film,
(3) The process of peeling a base film from a protective film,
(4) A step of dicing the semiconductor wafer and the protective film.

  The dicing in the step (4) can be performed according to a conventional method using a dicing sheet. A semiconductor chip having a protective film on the back surface is obtained by dicing. The chip is picked up by a general-purpose means such as a collet and placed on the substrate. By using the protective film of the present invention, it is difficult for minute damage to occur on the cut surface of the chip, and a semiconductor device can be manufactured with a high yield.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not restrict | limited to the following Example.

<Preparation of composition for forming protective film>
In each example and each comparative example, the component (A) in an amount shown in Table 1 was dissolved in about 50 parts by mass of cyclohexane. The obtained solution was mixed with other components in the amounts shown in Table 1 to obtain a composition having a solid content of about 70% by mass.

Each component shown in Table 1 is as follows.
-(A) component (A-1) Phenoxy resin: Mw about 60,000, JER 1256 (made by Japan Epoxy Resin Co., Ltd.)
(A-2) Polyimide resin: obtained by the synthesis method described later.

(A-3) Acrylic resin: copolymer of 55 parts by mass of butyl acrylate, 15 parts by mass of methyl methacrylate, 20 parts by mass of glycidyl methacrylate, and 15 parts by mass of 2-hydroxyethyl acrylate (weight average molecular weight 900,000, (Glass transition temperature -28 ° C)
Component (B) Epoxy resin: RE310S (manufactured by Nippon Kayaku Co., Ltd.), viscosity at 25 ° C. and 15 Pa. s (Bisphenol A type epoxy resin)
Component (C) Silica: SE2050, average particle size 0.5 μm, maximum particle size 5 μm, KBM-403 treated product, manufactured by Admatechs Co., Ltd. (spherical silica manufactured by deflagration method)
Silicone fine particles coated with polyorganosilsesquioxane resin (trade name: KMP600, manufactured by Shin-Etsu Chemical Co., Ltd.)
-(D) component Dicyandiamide (DICY-7): Japan Epoxy Resin Co., Ltd.

..Synthesis of polyimide resin (A-2):
Diaminosiloxane (KF-8010, manufactured by Shin-Etsu Chemical Co., Ltd.) represented by the following structural formula 49 in a 1-liter separable flask equipped with a 25 ml water quantitative receiver with a cock connected to a reflux condenser, a thermometer, and a stirrer 0.01 parts by mass and 100 parts by mass of 2-methylpyrrolidone as a reaction solvent were added and stirred at 80 ° C. to disperse the diamine. A solution of 42.68 parts by mass of 6FDA (2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane) and 100 parts by mass of 2-methylpyrrolidone as an acid anhydride was added dropwise thereto at room temperature for 2 hours. By carrying out a stirring reaction, an acid anhydride-rich amic acid oligomer was synthesized.

次に、下記式：

Next, the following formula:

25 ml water quantitative receiver with a cock connected to a reflux condenser, 8.31 parts by mass of a diamine having a phenolic hydroxyl group (HAB, manufactured by Wakayama Seika) and 100 parts by mass of 2-methylpyrrolidone, A 1-liter separable flask equipped with a total and a stirrer was charged and dispersed, and the above-mentioned acid anhydride-rich amic acid oligomer was added dropwise, followed by stirring at room temperature for 16 hours to synthesize a polyamic acid solution. Thereafter, 25 ml of xylene was added, the temperature was raised, and the mixture was refluxed at about 180 ° C. for 2 hours. Confirm that the specified amount of water has accumulated in the moisture meter and that no water has flowed out, and remove xylene at 180 ° C while removing the effluent collected in the meter. did. After completion of the reaction, the reaction solution obtained in a large excess of methanol was added dropwise to precipitate a polymer and dried under reduced pressure to obtain a polyimide resin having a phenolic hydroxyl group in the skeleton.

When the infrared absorption spectrum of the obtained polyimide resin was measured, absorption based on polyamic acid indicating that there was an unreacted functional group did not appear, and absorption based on an imide group was confirmed at 1780 cm ⁻¹ and 1720 cm ^−1. Absorption based on a phenolic hydroxyl group was confirmed at 3500 cm ⁻¹ . The obtained resin had a polystyrene equivalent weight average molecular weight of 55,000 and a functional group equivalent of 760 g / eq.

<Preparation of peelable substrate film>
-A base film provided with an alkyd resin release agent layer on one side was prepared as follows. Untreated polyethylene terephthalate resin film (Mitsubishi Polyester Film Co., Ltd., trade name “T-100”, thickness 50 μm, center line average roughness (Ra) 0.0833 μm, maximum protrusion height (Rp) 0.6833 μm) On one side, a mixture of stearyl-modified alkyd resin and methylated melamine (manufactured by Hitachi Chemical Polymer Co., Ltd., trade name “Tesfine 303”, solid content 20 mass%) 100 parts by mass of acid catalyst p-toluenesulfonic acid 3 The thermosetting alkyd resin liquid added with and mixed with parts by mass was applied by Meyer bar # 4, dried at 140 ° C. for 1 minute, and thermally cured to form a release agent layer (thickness 0.1 μm).

-The base film which provided the silicone resin-type release agent layer in the single side | surface was produced as follows. Untreated polyethylene terephthalate resin film (Mitsubishi Polyester Film Co., Ltd., trade name “T-100”, thickness 50 μm, center line average roughness (Ra) 0.0833 μm, maximum protrusion height (Rp) 0.6833 μm) On one side, a peelable silicone (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “Silicone KS-847H”, solid content 1.4% by mass) is added to 100 parts by mass of a platinum catalyst (Shin-Etsu Chemical Co., Ltd., trade name “ PL-50T ") was added and mixed with 2 parts by weight of a release agent applied by Meyer bar # 4 and dried at 130 ° C for 1 minute to form a release agent layer (thickness 0.1 µm).

<Creation of protective film forming sheet>
The composition for forming a protective film prepared as described above is applied to each release agent layer side of the PET film provided with the alkyd resin release agent layer prepared above and the PET film provided with the silicone resin release agent layer. After coating with a blade coater at 0.1 m / min, it was dried by heating at 110 ° C. for 10 minutes to form a protective film with a thickness of 25 μm, and a protective film-forming sheet was produced.

  For comparison, a protective film with a thickness of 25 μm was formed on one side of an untreated PET film with a thickness of 50 μm in the same manner, to produce a protective film-forming sheet.

<Evaluation test>
Using the above protective film forming sheet, the protective film according to the method of the present invention was evaluated as follows. The results are shown in Table 1.

..Scratch test:
The protective film side of the protective film forming sheet prepared above was attached to one side of a silicon wafer having dimensions of 220 μm × 45 mm × 45 mm at 70 ° C. (silicon wafer surface temperature). Next, a scratch test was performed on the PET film before peeling the PET film from the cured protective film. Further, a scratch test was performed on the protective film exposed by peeling the PET film from the cured protective film. Thus, it was examined whether or not the protective film was damaged.

  In the scratch test, a protective film or a protective film with a PET film was directly reciprocated 10 times at a speed of 20 mm / sec and a stroke of 4 cm using a scratch test device (manufactured by KNT Corporation).

.. Warpage measurement test:
On the mirror surface of an 8-inch silicon wafer having a thickness of 220 μm, KJR-651 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) was spin-coated at 1500 rpm as an organic resin circuit protective layer to obtain a circuit protective layer having a thickness of 8 μm. . The amount of warpage of the 8-inch wafer at this time was 300 μm. Thereafter, the protective film side of the protective film-forming sheet prepared above is attached to the back surface of the 8-inch silicon wafer having the circuit protective layer at 70 ° C., and then cured by heating at 190 ° C. for 1 hour. It was. Next, the curvature measurement at room temperature was performed with the curvature measuring apparatus (Acrometrics company make, brand name: PS400). The warpage amount was displayed as a positive value when a warp that protruded downward was shown with the circuit protective layer side up. The difference in height between the two points on the outer peripheral portion having the largest warpage and the central portion was taken as the amount of warpage.

..Chipping test:
Using the protective film-forming sheet obtained above and using a protective film application apparatus (FM-114 manufactured by Technovision), a silicon wafer (8-inch unpolished wafer having a thickness of 725 μm at 70 ° C. The wafer was affixed to a wafer having a thickness of 220 μm by polishing # 2000 using DAG-810 manufactured by Co., Ltd. Thereafter, the base sheet is peeled off from the attached protective film, and then the silicon wafer is diced into 10 mm × 10 mm square chips under the following conditions. The presence or absence of chipping of 25 μm or more was examined.

Dicing conditions:
Device used: DISCO Dicer DAD-341
Cutting method: Single Blade rotation speed: 30000rpm
Blade speed: 50 mm / sec
Dicing film thickness 85μm, cutting into dicing film: 15μm

  The protective film of the present invention can improve the yield of silicon chips and is useful for the manufacture of semiconductor devices.

Claims (5)

A protective film-forming sheet comprising a base film having peelability on one side and a protective film for a semiconductor chip made of a thermosetting resin composition provided on the peelable single side of the base film. Pasted so that it touches the back of the semiconductor wafer,
Next, the protective film is cured,
Next, the base film is peeled from the protective film thus cured.
A method for manufacturing a semiconductor chip. The thermosetting resin composition is
(A) 100 parts by mass of at least one resin selected from the group consisting of phenoxy resin, polyimide resin, and (meth) acrylic resin,
(B) 5 to 200 parts by mass of an epoxy resin,
(C) 10-900 parts by mass of filler, and (D) an effective amount of epoxy resin curing catalyst,
The method for manufacturing a semiconductor chip according to claim 1, wherein the semiconductor chip is a composition containing the semiconductor chip.   The method for producing a semiconductor chip according to claim 2, wherein 10 to 100 parts by mass of the filler (C) are silicone rubber fine particles coated with a polyorganosilsesquioxane resin.   The method for producing a semiconductor chip according to any one of claims 1 to 3, wherein the peelability of the base film on one side is provided by forming a release agent coating on the surface of the base film. .   The semiconductor chip manufacturing method according to claim 4, wherein the release agent is a silicone release agent or an alkyd release agent.