JP6001273B2 - Protective film for semiconductor wafer and method for manufacturing semiconductor chip - Google Patents

Description

  The present invention relates to a protective film for a semiconductor wafer and a method for manufacturing a semiconductor chip.

  In order to reduce the mounting area of the semiconductor chip and reduce the height, a flip chip connection method is used. In this connection method, a semiconductor chip is obtained by dicing a wafer having a circuit and connection bumps formed on the surface, and after the surface of the chip is connected to a substrate, resin sealing or the like is used to protect the semiconductor chip. To do.

  A chip protective film forming sheet that prevents the chip from being damaged by the vibration of the rotary blade in the dicing process (hereinafter referred to as “chipping”) and acts as a sealing film instead of resin sealing is known ( Patent Document 1 and Patent Document 2).

  In addition, one using a reinforcing material having a low linear expansion coefficient for preventing twisting of the IC card (Patent Document 3) and one using a reinforcing material for preventing cracking of the semiconductor chip in the IC card are known. (Patent Document 4).

  The chip protective film is used by being attached to the back surface of the wafer. Therefore, it is this protective film that is finally cut by the rotary blade in the dicing process. However, since the resin component contained in the protective film has stretchability, it is difficult to cut, and there is a problem that the rotary blade is clogged to vibrate the rotary blade and damage the wafer.

  When using a reinforcing material with a low coefficient of linear expansion to prevent twisting of the IC card, if the reinforcing material is not present when the IC card is subjected to twisting or bending stress, a semiconductor chip with a low elastic modulus Although the stress can be relieved in the portion without the crack, if the reinforcing material is contained in the whole, the thin semiconductor chip is cracked by the twisting or bending stress.

  In the method of attaching the reinforcing material to the semiconductor chip in the IC card, the quality of the product can be improved by multiple curing processes, adhesive sticking out, displacement and inclination of the reinforcing layer, and variation in reinforcing strength due to uneven thickness of the adhesive. Variations and a significant decrease in productivity occur.

JP 2002-280329 A JP 2004-260190 A Japanese Patent Laid-Open No. 10-24686 JP 2000-268152 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a semiconductor wafer protective film excellent in cutting characteristics by a dicer and a method of manufacturing a highly productive semiconductor chip.

In order to solve the above problems, according to the present invention,
A protective film for a semiconductor wafer comprising a base film and a protective film formed on the upper side of the base film, wherein the protective film contains the following components (A) to (E): A protective film for a semiconductor wafer is provided.
(A) At least one selected from the group consisting of phenoxy resin, polyimide resin, and (meth) acrylic resin: 100 parts by mass,
(B) Epoxy resin: 5-200 parts by mass,
(C) Fillers other than the fibrous inorganic filler: 100 to 400 parts by mass,
(D) Epoxy resin curing catalyst: catalyst amount, and (E) fibrous inorganic filler: 25-5000 parts by mass

  The protective film of such a protective film for a semiconductor wafer has a fibrous inorganic filler, so that chipping can be prevented when a semiconductor chip is obtained by dicing the semiconductor wafer. Moreover, the protective film of this protective film for semiconductor wafers has a high bending strength, and can prevent chip cracking due to bending stress when used in the market.

Further, the protective film comprises a reinforcing layer and an adhesive layer,
The adhesive layer preferably comprises the following components (A) to (D), and the reinforcing layer preferably comprises the following component (E).
(A) At least one selected from the group consisting of phenoxy resin, polyimide resin, and (meth) acrylic resin: 100 parts by mass,
(B) Epoxy resin: 5-200 parts by mass,
(C) Fillers other than the fibrous inorganic filler: 100 to 400 parts by mass,
(D) Epoxy resin curing catalyst: catalyst amount, and (E) fibrous inorganic filler: 1000 to 5000 parts by mass

  Thus, if the protective film is composed of two layers of the reinforcing layer and the adhesive layer, the chipping prevention and the bending strength of the semiconductor chip are further improved, and high productivity can be realized. .

  Moreover, the phenoxy resin in the component (A) is a bisphenol A type phenoxy resin or a bisphenol F type phenoxy resin, and the epoxy resin of the component (B) is a liquid bisphenol A type epoxy resin or a liquid bisphenol F type epoxy resin. Preferably there is.

  If it is a combination of such (A) component and (B) component, the protective film for semiconductor wafers will become further excellent in the cutting | disconnection characteristic by a dicer.

  The present invention also relates to a method of manufacturing a semiconductor chip by dicing a semiconductor wafer, wherein the semiconductor chip is attached to the back surface of the semiconductor wafer by attaching the protective film for the semiconductor wafer to the semiconductor wafer and dicing all at once. A method for manufacturing a semiconductor chip is provided, wherein a semiconductor chip having a protective film of the same size as that of the semiconductor chip is manufactured.

  With such a method of manufacturing a semiconductor chip, chipping at the time of cutting is suppressed, and furthermore, since the bending strength of the protective film on the back surface of the semiconductor chip is high, the semiconductor chip has high productivity. Can be realized.

  In the semiconductor wafer protective film of the present invention, since the protective film has a fibrous inorganic filler, it can be easily cut by a dicer, chipping prevention and bending strength of the semiconductor chip are improved, and high productivity can be realized. it can.

It is sectional drawing which shows an example of the protective film for semiconductor wafers of this invention. It is sectional drawing which shows another example of the protective film for semiconductor wafers of this invention. It is sectional drawing which shows another example of the protective film for semiconductor wafers of this invention.

As a result of intensive studies to achieve the above object, the present inventors
A protective film for a semiconductor wafer comprising a base film and a protective film formed on the upper side of the base film, wherein the protective film contains the following components (A) to (E): It has been found that the protective film for semiconductor wafers can be a protective film for semiconductor wafers having excellent cutting characteristics.
(A) At least one selected from the group consisting of phenoxy resin, polyimide resin, and (meth) acrylic resin: 100 parts by mass,
(B) Epoxy resin: 5-200 parts by mass,
(C) Fillers other than the fibrous inorganic filler: 100 to 400 parts by mass,
(D) Epoxy resin curing catalyst: catalyst amount, and (E) fibrous inorganic filler: 25-5000 parts by mass

(A) At least one phenoxy resin selected from the group consisting of a phenoxy resin, a polyimide resin, and a (meth) acrylic resin is a resin derived from epichlorohydrin and bisphenol A or bisphenol F or the like. Preferably, the polystyrene equivalent weight average molecular weight measured by GPC 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 equal to or higher than the lower limit value, it is easy to form a film, while when the weight average molecular weight is equal to or lower than the upper limit value, sufficient softness along the unevenness of the substrate surface having a fine circuit pattern is obtained. This is preferable.

  Examples of the phenoxy resin include those sold under the trade names PKHC, PKHH, and PKHJ (all manufactured by Sakai Chemical Industry Co., Ltd.), and the commercial names Epicoat 4250, Epicoat 4275, and Epicoat 1255HX30 of the mixed type of bisphenol A and bisphenol F. (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 Toto 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-described weight average molecular weight. The phenoxy polymer has an epoxy group at the end, which reacts with the component (B) described later.

（式中、Ｘは芳香族環又は脂肪族環を含む四価の有機基、Ｙは二価の有機基、ｑは１〜３００の整数である。） As a polyimide resin, what contains the following repeating unit 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.)

  Preferably, the polystyrene equivalent weight average molecular weight measured by GPC 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 equal to or higher than the lower limit value, it is easy to form a film, while when the weight average molecular weight is equal to or lower than the upper limit value, sufficient softness along the unevenness of the substrate surface having a fine circuit pattern is obtained. This is preferable.

（式中、Ｘ、Ｙ、ｑは上で定義したとおりである。） The polyimide resin can be obtained by dehydrating and ring-closing a polyamic acid resin having the following repeating units by a conventional method.

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

（但し、Ｘは上記と同様の意味を示す。）
で表されるテトラカルボン酸二無水物と、下記構造式（４）
Ｈ₂Ｎ−Ｙ−ＮＨ₂ （４）
（但し、Ｙは上記と同様の意味を示す。）
で表されるジアミンを、常法に従って、ほぼ等モルで、有機溶剤中で反応させることによって得ることができる。 The polyamic acid resin represented by the above formula has the following structural formula (3)

(However, X has the same meaning as described above.)
A tetracarboxylic dianhydride represented by the following structural 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), You may use combining these.

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

（式中、Ｒ¹は互いに独立に炭素数３〜９の二価の有機基であり、Ｒ²およびＲ³は、それぞれ独立に、非置換もしくは置換の炭素原子数１〜８の一価炭化水素基であり、ｍは１〜２００の整数である。）

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

Examples of R ¹ that is a divalent organic group having 3 to 9 carbon atoms include — (CH ₂ ) ₃ —, — (CH ₂ ) ₄ —, —CH ₂ CH (CH ₃ ) —, — ( An alkylene group such as CH ₂ ) ₆ — and — (CH ₂ ) ₈ —,

のいずれかで表されるアリーレン基、アルキレン・アリーレン基、
−（ＣＨ₂）₃−Ｏ−，−（ＣＨ₂）₄−Ｏ−等のオキシアルキレン基、下記式

An arylene group represented by any one of the following: an alkylene / arylene group,
Oxyalkylene groups such as — (CH ₂ ) ₃ —O— and — (CH ₂ ) ₄ —O—,

のいずれかで表されるオキシアリーレン基、下記式

An oxyarylene group represented by any of the following formulae

で表されるオキシアルキレン・アリーレン基等の、エーテル結合を含んでもよい二価炭化水素基が挙げられる。

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

Examples of R ² or R ³ include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a hexyl group, a cyclohexyl group, a 2-ethylhexyl group, and an octyl group. Allyl group, propenyl group, isopropenyl group, butenyl group, isobutenyl group, alkenyl group such as hexenyl group, aryl group such as phenyl group, tolyl group, xylyl group, aralkyl group such as benzyl group, phenylethyl group, etc. Groups in which part or all of the hydrogen atoms bonded to the carbon atoms of the hydrocarbon group are substituted with halogen atoms such as fluorine, bromine, chlorine, etc., for example, chloromethyl group, bromoethyl group, 3,3,3-trifluoro Examples include halogen-substituted alkyl groups such as propyl group, and among them, methyl group and phenyl group are preferable. A combination of two or more diaminosiloxane compounds can also be used.

  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.

式中、Ａは下記のいずれかの基

式中、Ｂは下記のいずれかの基

（式中、Ｒ⁴は、互いに独立に、水素原子又はフッ素、臭素、よう素などのハロゲン原子、あるいはアルキル基、アルケニル基、アルキニル基、トリフルオロメチル基、フェニル基などの非置換又は置換の炭素原子数１〜８の一価炭化水素基であり、各芳香環に付いている置換基は異なっていてもよく、ｎは０〜５の整数である。Ａ、Ｂはおのおの１種単独でも、２種以上の組み合わせでもよい。Ｒは水素原子、ハロゲン原子又は非置換もしくは置換の一価炭化水素基である。） Preferably, the polyimide resin has a phenolic hydroxyl group from the viewpoint of adhesiveness. 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 the following structure.

In the formula, A is any of the following groups:

In the formula, B is any of the following groups:

(In the formula, R ⁴ is independently of each other a hydrogen atom or a halogen atom such as fluorine, bromine or iodine, or an unsubstituted or substituted alkyl group, alkenyl group, alkynyl group, trifluoromethyl group, phenyl group or the like. It is a monovalent hydrocarbon group having 1 to 8 carbon atoms, and the substituents attached to each aromatic ring may be different, and n is an integer of 0 to 5. A and B may each be a single type. A combination of two or more may be used, and R is a hydrogen atom, 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 of R ⁴ include those similar to those exemplified for R ² and R ³ , and ethynyl, propynyl, and butynyl groups. And alkynyl groups such as a hexynyl group.

（上式中、Ｒ’は水素原子、フッ素、臭素、よう素などのハロゲン原子、又は炭素数１〜８の、アルキル基、アルケニル基、アルキニル基、トリフルオロメチル基、フェニル基などの非置換又はハロゲン置換の１価炭化水素基であり、各芳香族環に付いている置換基は異なっていてもよく、Ｘは単結合、メチレン基、又はプロピレン基である。ｎは上で定義したとおりである。） Moreover, the following are 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, X is a single bond, a methylene group, or a propylene group, and n is as defined above. .)

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

（式中、Ｒ⁴は上で定義したとおりである。）

(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 composition having a high adhesive force and forming a flexible adhesive layer can be obtained.

  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.

（式中、Ｒ⁴は上記と同じであり、各芳香環に付いている置換基は異なっていても構わない。Ｄは１種単独で用いても２種以上を併用してもよい。また、ｐは１〜３の整数である。）

(In the formula, R ⁴ is the same as above, and the substituents attached to each aromatic ring may be different. D may be used alone or in combination of two or more. , P is an integer from 1 to 3.)

  When a monoamine having a phenolic hydroxyl group is used, the amount is preferably 1 to 10 mol% based on 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 addition, in order to adjust the molecular weight of polyamic acid and polyimide resin, dicarboxylic acid anhydrides such as maleic anhydride and phthalic anhydride and / or aniline, n-butylamine, and monoamines having the above-mentioned phenolic hydroxyl groups are added. You can also 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.

  Examples of the (meth) acrylic resin include (meth) acrylic acid ester copolymers composed of structural units derived from (meth) acrylic acid ester monomers and (meth) acrylic acid derivatives. Here, the (meth) acrylic acid ester monomer is preferably a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 18 carbon atoms, such as methyl (meth) acrylate, ethyl (meth) acrylate, (meth ) Propyl acrylate, butyl (meth) acrylate, etc. are used. Examples of the (meth) acrylic acid derivative include (meth) acrylic acid, glycidyl (meth) acrylate, hydroxyethyl (meth) acrylate, and the like.

  By copolymerizing glycidyl methacrylate and the like to introduce a glycidyl group into the (meth) acrylic resin, compatibility with an epoxy resin as a thermosetting adhesive component described later is improved, and the glass transition temperature after curing ( Tg) is increased and the heat resistance is also improved. Further, by introducing a hydroxyl group into the acrylic polymer with hydroxyethyl acrylate or the like, it becomes easy to control the adhesion to the 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 is a resin different from the component (A), and preferably has an epoxy equivalent of 50 to 5000 g / eq, more preferably 100 to 500 g / eq.
Examples of such epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins (particularly liquid bisphenol A type epoxy resins or liquid bisphenol F type epoxy resins); glycidyls of phenols such as resorcinol, phenol novolac, and cresol novolac. Ethers: Glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; Glycidyl ethers of carboxylic acids such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; Active hydrogen bonded to nitrogen atoms such as aniline isocyanurate glycidyl group Glycidyl type or alkyl glycidyl type epoxy resins substituted with vinylcyclohexane diepoxide, 3,4-epoxycyclohexylmethy Carbon-carbon dicarbons in the molecule, such as -3,4-dicyclohexanecarboxylate, 2- (3,4-epoxy) cyclohexyl-5,5-spiro (3,4-epoxy) cyclohexane-m-dioxane. Examples include so-called alicyclic epoxides in which an epoxy is introduced by, for example, oxidizing a heavy bond. In addition, an epoxy resin having a biphenyl skeleton, a dicyclohexadiene skeleton, or a naphthalene skeleton can be used.

  Among these, bisphenol A type epoxy resin, bisphenol F type epoxy resin (particularly liquid bisphenol A type epoxy resin or liquid bisphenol F type epoxy resin), o-cresol novolak type epoxy resin and phenol novolak type epoxy resin are preferably used. . Two or more of these epoxy resins may be used in combination.

  (B) An epoxy resin is 5-200 mass parts with respect to 100 mass parts of (A) component, Preferably it is 10-200 mass parts, More preferably, 50-150 mass parts is mix | blended. When the component (A) and the component (B) are blended at such a ratio, an appropriate tack is exhibited before curing, and a sticking operation to the wafer can be stably performed. An excellent protective film can be obtained.

  In the combination of the component (A) and the component (B), the phenoxy resin in the component (A) is bisphenol A type phenoxy resin or bisphenol F type phenoxy resin, and the epoxy resin of the component (B) is liquid bisphenol A It is preferably a type epoxy resin or a liquid bisphenol F type epoxy resin.

(C) Fillers other than fibrous inorganic fillers (C) Component fillers include inorganic fillers other than fibrous inorganic fillers (non-fibrous inorganic fillers), such as silica, alumina, titanium oxide, carbon Conductive particles such as black and silver particles, and silicone resin powder, for example, a crosslinked spherical dimethylpolysiloxane fine powder having a structure in which dimethylpolysiloxane is crosslinked (Japanese Patent Laid-Open No. 3-93834), a crosslinked spherical polymethylsilsesquioxide Oxane fine powder (Japanese Patent Laid-Open No. 3-47848), fine powder obtained by coating the surface of a crosslinked spherical polysiloxane rubber with polymethylsilsesquioxane particles (Japanese Patent Laid-Open No. 7-196815, Japanese Patent Laid-Open No. 9-20631) Gazette) can be used.

  The blending amount of the filler is 100 to 400 parts by mass, preferably 150 to 350 parts by mass with respect to 100 parts by mass of the component (A). When the blending amount is equal to or more than the lower limit value, low water absorption, low linear expansion, and the like, which are blending purposes of the filler, can be sufficiently achieved. When the low water absorption cannot be achieved, the semiconductor device fails the moisture absorption reliability test, and when the low linear expansion coefficient cannot be achieved, the linear expansion coefficient mismatch occurs when the composite of the protective film for semiconductor wafer and the silicon wafer is cured. Occurs, causing a large warp and subsequent dicing becomes impossible. On the other hand, in the case of the upper limit or less, there is no fear that the viscosity of the composition for forming the protective layer is excessively increased, there is no possibility that the fluidity when applied to the base film is deteriorated, and the protective film is applied to the silicon wafer. There is no possibility that sticking at a low temperature becomes difficult, and it is possible to prevent the composite of the wafer and the protective film for a semiconductor wafer from warping greatly. It is preferable that the content rate of a filler is 30-80 mass% of a protective film.

  As silica, fused silica or crystalline silica is 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 protective film (adhesive layer) can be obtained. Further, in recent years, the thickness of the adhesive layer is often required to be 15 to 50 μm. However, if the average particle diameter of silica is within the above range, even if secondary agglomerated particles are present, the requirement is satisfied. Easy to fill.

  Silicone rubber fine particles whose surface is coated with a polyorganosilsesquioxane resin can be produced by the method described in the above-mentioned publications (JP-A-7-196815, JP-A-9-20631), or Commercially available silicone composite powder KMP600 series (manufactured by Shin-Etsu Chemical Co., Ltd.) can be used. KMP600 is preferably used from the viewpoint of particle size.

The filler (C) is preferably an inorganic filler, more preferably silica, and most preferably silica produced by a deflagration method. The silica is easily wetted by the resin component and is 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- Glycidoxypropyl-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, α-glycidoxybutyltrimethoxysilane, α-glycidoxybutyl Triethoxysilane, -Glycidoxybutyltrimethoxysilane, β-glycidoxybutyltriethoxysilane, γ-glycidoxybutyltrimethoxysilane, γ-glycidoxybutyltriethoxysilane, δ-glycidoxybutyltrimethoxysilane, δ -Glycidoxybutyltriethoxysilane, (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) ethyl Riphenoxysilane, γ- (3,4-epoxycyclohexyl) propyltrimethoxysilane, γ- (3,4-epoxycyclohexyl) propyltriethoxysilane, δ- (3,4-epoxycyclohexyl) butyltrimethoxysilane, δ Trialkoxysilanes such as-(3,4-epoxycyclohexyl) butyltriethoxysilane, N-β- (aminoethyl) γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) γ-aminopropylmethyldiethoxysilane Γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, trimethoxysilylpropyl nadic acid anhydride, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane are preferably used.

(D) Epoxy resin curing catalyst The epoxy resin curing catalyst is preferably a type that cures when heated, so-called thermally activated latent epoxy resin curing agent. Examples include dicyandiamide, imidazole compounds, various onium salts, dibasic acid dihydrazide compounds, and the like, and two or more of these may be used in combination. The amount of the curing catalyst may be an amount effective as a catalyst (catalytic amount), but is usually 0.1 to 20 parts by mass, preferably 1 to 12 parts by mass with respect to 100 parts by mass of the epoxy resin. Used part.

(E) Fibrous inorganic filler As the fibrous inorganic filler, ceramic whisker such as glass fiber, calcium silicate fiber, potassium titanate fiber, carbon fiber, silicon nitride, potassium titanate, ceramic fiber, metal fiber, etc. Can be mentioned. Of these, glass fiber is most preferred. The form of the glass fiber is not particularly specified, and any of roving, strand, chopped strand, milled fiber, a pulverized strand called glass powder, and the like may be used.

The shape of the fibrous inorganic filler of component (E) is not particularly limited. For example, in the case of glass fiber and carbon fiber, the fiber diameter is preferably 10 to 100 μm, and more preferably 15 to arbitrariness favored those that are 60μm. Further, the aspect ratio (fiber length / fiber diameter ratio) is preferably 3 or more, more preferably 5 or more in the molded body.
If the fiber diameter is 10 μm or more, the production thereof is not likely to be difficult, and if it is 100 μm or less, the mechanical properties of the molded article, particularly the impact strength, is not liable to decrease, which is preferable. An aspect ratio of 3 or more is preferable because a sufficient reinforcing effect can be obtained.

  As a method of improving the reinforcing effect of the protective film, a glass nonwoven fabric in which a fibrous inorganic filler is randomly distributed in the protective film, a glass nonwoven fabric (Nippon Vilene Co., Ltd. glass nonwoven fabric cumulus), or a long one It is preferable to use a knitted fiber (IPC standard 3313 glass cloth, etc., manufactured by Nittobo Co., Ltd.). As the matrix resin, an epoxy resin, a polyamide resin, a phenol resin, or the like is preferably used because the protective film contains an epoxy resin as the component (B).

The fibrous inorganic filler may be randomly dispersed in the protective film, but the protective film has a two-layer structure of an adhesive layer and a reinforcing layer, and the fibrous inorganic filler is dispersed only in the reinforcing layer. Preferably it is. As the matrix resin for the reinforcing layer, a resin for the adhesive layer may be used.
When the fibrous inorganic filler is dispersed in the protective film, at least one selected from the group consisting of the phenoxy resin, the polyimide resin, and the (meth) acrylic resin as the component (A) is 100 parts by mass. 25 to 5000 parts by mass are preferred. More preferably, it is 40 to 3000 parts by mass. If the blending amount is equal to or greater than the lower limit value, the protective film has a high linear expansion coefficient and is not likely to be greatly warped, and it is preferable that the bending strength is not lowered due to chipping during dicing. Further, when the blending amount is not more than the upper limit value, there is no fear that the smoothness of the adhesion surface of the protective film with respect to the silicon wafer is lowered, there is no possibility that the adhesion force is lowered, and the bending strength is high. .

Other Components The protective film of the present invention may contain an epoxy resin curing agent and various additives in addition to the components described above. As the curing agent, phenol resins, for example, condensates of phenols such as alkylphenols, polyhydric phenols, naphthols, and aldehydes are used, preferably phenol novolak resins, o-cresol novolak resins, p-cresol novolak resins. T-butylphenol novolak resin, dicyclopentadiene cresol resin, polyparavinylphenol resin, bisphenol A type novolak resin, bisphenol F type novolak resin, or modified products thereof.

  Examples of the additive include pigments and dyes. When these are blended and the protective film in the present invention is colored, the laser mark performance is improved. Furthermore, a silane coupling agent can be added for the purpose of improving the adhesion and adhesion between the protective film and the chip back surface. In addition, you may mix | blend a flame retardant, an antistatic agent, etc.

  The elastic modulus after curing of the protective film for a semiconductor wafer of the present invention is preferably 10 to 100 GPa. If the elastic modulus after curing is 10 GPa or more, the protective film for a semiconductor wafer can sufficiently withstand bending stress at the time of bending, and there is no possibility of causing a decrease in bending strength. In addition, when the elastic modulus is 100 GPa or less, there is no possibility that a large stress is generated on the silicon wafer side when the composite cured product of the semiconductor wafer protective film and the silicon wafer is warped, and a lot of chipping occurs. There is no risk of lowering the folding strength.

The protective film for semiconductor wafers in this invention is a semiconductor wafer provided with the base film 1 and the protective film 2 formed above the base film 1, as shown in FIGS. The protective film 10 for use. And the protective film 2 contains the (A)-(E) component mentioned above.
FIG. 1 shows a protective film 10 for a semiconductor wafer in which a fibrous inorganic filler 3 of component (E) is randomly dispersed in a protective film 2.
In FIG. 2, the protective film 2 is composed of a reinforcing layer 3 ′ and an adhesive layer 4. The adhesive layer 4 contains components (A) to (D), and the reinforcing layer 3 ′ (E) It contains a component. As the reinforcing layer 3 ′, glass cloth or the like is preferable. In this case, the content of the fibrous inorganic filler is preferably 25 to 1000 parts by mass with respect to 100 parts by mass of the component (A).
In FIG. 3, the protective film 2 comprises a reinforcing layer 3 ″ and an adhesive layer 4, and the adhesive layer 4 contains the components (A) to (D), and the reinforcing layer 3 ′. 'Contains the component (E). As the reinforcing layer 3 ″, a prepreg (for example, a glass cloth impregnated with an epoxy resin) is preferable. In this case, it is preferable that content of a fibrous inorganic filler is 1000-5000 mass parts with respect to 100 mass parts of (A) component. The arrangement with respect to the semiconductor wafer is preferably an arrangement method in which the coefficient of linear expansion is small in order to prevent warpage, and is preferably a semiconductor wafer (not shown), an adhesive layer 4 and a reinforcing layer 3 ″.

Although the following (Method 1)-(Method 3) are mentioned as a production method of the protective film for semiconductor wafers of this invention, It is not restrict | limited to these methods.
(Method 1) A fibrous inorganic filler (component (E)) is mixed and dispersed by a conventional method in an adhesive layer composition containing the components (A) to (D) dispersed with a solvent. Then, the protective film 2 is formed by coating on the base film 1 to form a protective film 10 for a semiconductor wafer in which the adhesive layer and the reinforcing layer are integrated (FIG. 1).
(Method 2) The above-described (A) to (A), in which a reinforcing layer 3 ′ composed of a network-like fibrous inorganic filler (component (E)) is disposed on the base film 1 and dispersed with a solvent from above. D) An adhesive layer composition containing the component is applied to produce a protective film 10 for a semiconductor wafer having a protective film 2 having a two-layer structure in which the adhesive layer 4 and the reinforcing layer 3 ′ are arranged in an inclined manner (FIG. 2). .
(Method 3) A film-like reinforcing layer 3 ″ made of a network-like fibrous inorganic filler impregnated with a matrix resin (component (E)) and an adhesive layer composition ((A) to A protective film 10 for a semiconductor wafer having a protective film 2 having a two-layer structure in which the film-like adhesive layer 4 prepared from the component (D) is bonded is prepared (FIG. 3).

  The protective film 2 in (Method 1) and the adhesive layer 4 in (Method 2) and (Method 3) are made of a composition obtained by mixing the corresponding components on the base film 1, and have a thickness of 5 to 100 μm, preferably Can be obtained by applying by a known method such as a gravure coater so as to be 10 to 60 μm. In addition, said composition can be apply | coated by disperse | distributing to a solvent, for example, cyclohexanone, as needed.

  As the base film 1, a polyethylene film, a polypropylene film, a polyvinyl chloride film, a polyethylene terephthalate film, a polyimide film, or the like is used. When the base film 1 is peeled after the protective film 2 is cured, a polyethylene terephthalate film or a polyimide film excellent in heat resistance is preferably used. At that time, a silicone resin or the like may be applied to the surface of the base film to perform a release treatment, or a peelable layer may be formed between the base film 1 and the protective film 2.

  The film thickness of the base film 1 is 5 to 200 μm, preferably 10 to 150 μm, particularly preferably about 20 to 100 μm.

The protective film for a semiconductor wafer is used, for example, by the following method.
(1) The process of sticking the protective film of the protective film for semiconductor wafers in this invention on the back surface of the semiconductor wafer in which the circuit was formed in the surface,
(2) The process of peeling the base film of the protective film for semiconductor wafers,
(3) a step of curing the protective film by heating,
(4) A step of dicing the semiconductor wafer and the protective film.
Here, steps (3) and (4) may be performed in reverse order.

  The dicing 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 for a semiconductor wafer 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.

The cyclohex non Preparation about 50 parts by weight of the protective layer-forming composition was dissolved (A) component of the mass parts shown in Table 1. 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 and components used below are as follows.
(A) component Phenoxy resin: Mw about 60,000, JER 1256 (made by Japan Epoxy Resin Co., Ltd.)
Polyimide resin 1: The synthesis method will be described later.
Acrylic resin 1: 55 parts by weight of butyl acrylate, 15 parts by weight of methyl methacrylate, 20 parts by weight of glycidyl methacrylate, and 15 parts by weight of 2-hydroxyethyl acrylate (weight average molecular weight 900,000, glass transition temperature − 28 ℃)
(B) Component Epoxy resin: RE310S (manufactured by Nippon Kayaku Co., Ltd.), viscosity at 25 ° C. and 15 Pa. s
(C) Component Silica: SC2050 , average particle size 0.5 μm, maximum particle size 5 μm, KBM-403 treated product, (D) component dicyandiamide (DICY-7): manufactured by Japan Epoxy Resin Co., Ltd. ( E) Component Epoxy impregnated glass cloth EG tape Type S: Arisawa Seisakusho glass cloth: Nittobo IPC standard 3313 Glass cloth Glass fiber: Nippon Electric Glass milled fiber GP-10MA (fiber diameter 10 μm, average fiber length 70 μm, Aspect ratio 7)

次に、下記式：

で示されるフェノール性水酸基を有するジアミン（ＨＡＢ、和歌山精化製）８.３１質量部と１００質量部の２−メチルピロリドンを、還流冷却器が連結されたコック付きの２５ｍｌ水分定量受器、温度計、攪拌器を備えた１リットルのセパラブルフラスコに仕込み、分散させ、前出の酸無水物リッチのアミック酸オリゴマーを滴下した後、室温で１６時間攪拌し、ポリアミック酸溶液を合成した。その後、キシレン２５ｍｌを投入してから温度を上げ、約１８０℃で２時間還流させた。水分定量受器に所定量の水がたまっていること、水の流出が見られなくなっていることを確認し、水分定量受器にたまっている流出液を除去しながら、１８０℃でキシレンを除去した。反応終了後、大過剰のメタノール中に得られた反応液を滴下し、ポリマーを析出させ、減圧乾燥して、骨格中にフェノール性の水酸基を有するポリイミド樹脂を得た。
得られたポリイミド樹脂の赤外吸光スペクトルを測定したところ、未反応の官能基があることを示すポリアミック酸に基づく吸収は現れず、１７８０ｃｍ^-1及び１７２０ｃｍ^-1にイミド基に基づく吸収を確認し、３５００ｃｍ^-1にフェノール性水酸基に基づく吸収を確認した。得られた樹脂のポリスチレン換算の重量平均分子量は５５，０００であり、官能基当量は７６０ｇ／ｅｑであった。 A diaminosiloxane (KF-8010, Shin-Etsu) represented by the following structural formula was placed in a 1-liter separable flask equipped with a 25 ml moisture determination receiver with a cock connected to a synthetic reflux condenser of polyimide resin 1, a thermometer, and a stirrer. (Chemical Co., Ltd.) 49.01 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.

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 protective film for semiconductor wafer (Examples 1 to 5 and Comparative Example 1)
The adhesive layer composition liquids (coating liquids 1 to 5) shown in Table 1 were prepared, and the layer thickness was 20 μm on the 115 μm epoxy prepreg reinforcing layer in the example and on the 50 μm SUS304 reinforcing layer in the comparative example. The adhesive layer was applied as described above, and dried by heating at 110 ° C. for 10 minutes to form 135 and 70 μm protective films.

(Example 6)
75 μm glass cloth IPC standard 3313 was placed on a 38 μm PET film surface-treated with silicone, and coating liquid 1 in Table 1 was applied from above so that the adhesive layer had a thickness of 15 μm. The film was dried by heating at 110 ° C. for 10 minutes to form a 90 μm protective film.

(Example 7)
The coating solution 6 containing glass fiber in Table 2 was applied on a 38 μm PET film surface-treated with silicone so that the protective film had a thickness of 50 μm, and dried by heating at 110 ° C. for 10 minutes, to 50 μm. A protective film was formed.
(Note that the coating liquid 6 has a composition in which glass fibers are contained in the coating liquid 1.)

(Comparative Examples 2 and 3)
A protective film of 135 μm was formed in the same manner as in Example 7 except that the coating liquids 4 and 5 were used.

The protective film obtained was cured at 175 ° C. for 4 hours, and then a strip sample having a width of 5 mm and a length of 40 mm was prepared as a measurement sample. Using Seiko Instruments DMA6100, data at 25 ° C. when the temperature was raised from 3 ° C./min from 1 ° C. to a strain width of 10 μm from 0 ° C. to 200 ° C. was taken as the tensile modulus.

The protective film obtained by the dicing test was obtained by using Technovision FM-114 at 50 ° C. and using a 75 μm thick silicon wafer (8-inch unpolished wafer, manufactured by DISCO Corporation, DAG-810). The wafer was abraded to a thickness of 75 μm by polygrind polishing. The protective film was cured by curing the silicon wafer with the protective film at 175 ° C./4 hours with a dryer. The silicon wafer with protective film was diced into 10 mm × 10 mm square chips under the following conditions, and the cut end surfaces of the 40 chips obtained were observed, and when there was no chipping of 50 μm or more, the chip was accepted.

Dicing condition equipment: DISCO Dicer DAD-341
Cutting method: Single dicing blade: ZH05-SD3500-N1-70EE
Blade rotation speed: 30000 rpm
Blade speed: 30 mm / sec
Dicing film thickness 110 μm, cutting into dicing film: 50 μm

Folding strength measurement test The bending strength of 40 chips of 10 mm × 10 mm square obtained in the dicing test of the test destination was measured under the following conditions, and the average value was taken as the measurement result. The results are shown in Table 3 .

Folding strength measurement condition equipment: Shimadzu Corporation Autograph
Anti-folding jig: 4 mm wide Distance between wedge-shaped fulcrums: 6 mm
Wedge jig speed: 0.01 m / min

  The protective films for semiconductors in which the protective films of Examples 1 to 7 contain a fibrous inorganic filler have high tensile elastic modulus, dicing performance, and bending strength, and can realize high productivity of semiconductor chips. On the other hand, the protective film for semiconductors not containing the fibrous inorganic filler of Comparative Examples 1 to 3 had low dicing performance and inferior bending strength.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. It is contained in the technical range.

  DESCRIPTION OF SYMBOLS 1 ... Base film, 2 ... Protective film, 3 ... Fibrous inorganic filler, 3 ', 3 "... Reinforcement layer, 4 ... Adhesive layer, 10 ... Protective film for semiconductor wafers.

Claims (3)

A protective film for a semiconductor wafer comprising a base film and a protective film formed on the upper side of the base film,
The protective film comprises a reinforcing layer and an adhesive layer,
Wherein the adhesive layer is to be contain the following (A) ~ (D) component, the reinforcing layer is Ri greens contain the following component (E), those that are inclined arranged A protective film for semiconductor wafers.
(A) At least one selected from the group consisting of phenoxy resin, polyimide resin, and (meth) acrylic resin: 100 parts by mass,
(B) Epoxy resin: 5-200 parts by mass,
(C) Fillers other than the fibrous inorganic filler: 100 to 400 parts by mass,
(D) Epoxy resin curing catalyst: catalyst amount, and (E) network-like fibrous inorganic filler: 25 to 5000 parts by mass   The phenoxy resin in the component (A) is a bisphenol A type phenoxy resin or a bisphenol F type phenoxy resin, and the epoxy resin in the component (B) is a liquid bisphenol A type epoxy resin or a liquid bisphenol F type epoxy resin. The protective film for a semiconductor wafer according to claim 1. A method of manufacturing a semiconductor chip by dicing a semiconductor wafer, wherein the protective film for a semiconductor wafer according to claim 1 or 2 is attached to the semiconductor wafer, and dicing is performed on the back surface. A method of manufacturing a semiconductor chip, comprising manufacturing a semiconductor chip having a protective film of the same size as the semiconductor chip.

Images