TW201632568A - Protective film forming film - Google Patents

Abstract

In order to form a protective film for protecting a semiconductor wafer, the film for forming a protective film of the present invention has a Shore D hardness of 55 or more on the surface of the film after curing, and a Young's modulus (23 ° C) after hardening of 1.0 × 109 Pa. the above.

Description

Protective film forming film

The present invention relates to a film for forming a protective film used for protecting a back surface of, for example, a semiconductor wafer.

Conventionally, a semiconductor device has been fabricated using a mounting method called a face down method. In the face-down method, the semiconductor wafer is bonded to the substrate or the like on the surface of the wafer on which the electrode is formed, such as a wafer, and the protective film is protected by peeling off the back surface of the wafer. The protective film is known to be formed, for example, by a film for forming a protective film. For the film for forming a protective film, for example, a thermosetting component made of an epoxy resin or the like disclosed in Patent Document 1 and a binder polymer component made of an acrylic polymer or the like are known.

When a film for forming a protective film is used, generally, a film for forming a protective film is attached to the back surface of a semiconductor wafer to cure the film for forming a protective film, and then a film is formed by laminating the semiconductor wafer and the cured protective film. The wafer is cut together and singulated to obtain a semiconductor wafer with a protective film. When the semiconductor wafer is diced, it is generally held by a dicing sheet or the like attached to the back surface of the wafer. And the semiconductor wafer singulated by cutting The cut sheet or the like is lifted by the needle from the back side, and picked up by a chuck or the like.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: WO2014/1587426

However, in order to perform stable cutting, the semiconductor wafer is desirably held by the dicing tape with a high adhesion force. However, if the adhesion force of the dicing tape is increased, the pickup force at the time of picking up the semiconductor wafer also becomes high, and the defect that the needle mark is attached to the surface of the protective film is likely to occur.

The present invention has been made in view of the above problems, and an object thereof is to provide a film for forming a protective film which can prevent needle marks from occurring on the surface of a protective film.

As a result of the positive review, the present inventors have found that by setting the Shore D hardness and Young's modulus of the film for forming a protective film after curing to a certain value or more, it is possible to suppress needle marks formed on the protective film during pick-up. The present invention has been completed. The present invention provides the following (1) to (10).

(1) A film for forming a protective film for forming a protective film for protecting a semiconductor wafer, wherein a surface hardness of the film after hardening is 55 or more, and a Young's modulus (23 ° C) after hardening is 1.0. ×10 ⁹ Pa or more.

(2) The film for forming a protective film according to the above (1), which comprises an acrylic polymer (A) and an epoxy curable component (B).

(3) The film for forming a protective film according to the above (2), wherein the epoxy-based curable component (B) is a condensed cyclic aromatic compound (b1) having an epoxy group.

(4) The film for forming a protective film according to the above (3), wherein the condensed cyclic aromatic compound (b1) having an epoxy group is a compound represented by the following formula (I) or (II),

(In the formula (I), CR represents a condensed polycyclic aromatic hydrocarbon group, R ¹ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and m represents an integer of 2 to 6).

(In the formula (II), CR ¹ and CR ² represent a condensed polycyclic aromatic hydrocarbon group, and the condensed polycyclic aromatic hydrocarbon groups may be the same or different, and R ² represents a divalent hydrocarbon group. The hydrocarbon group may have a substituent, R ³ represents an alkyl group having a carbon number of 1 to 10 or a glycidyl ether group, n represents an integer of 0 to 3, and p is an integer of 0 to 10. If p is 0, R ² represents a single bond. , q represents an integer from 1 to 3).

(5) The film for forming a protective film according to any one of the above (2), wherein the monomer constituting the acrylic polymer (A) is an alkyl group having a carbon number of 1 to 8 (methyl group). ) alkyl acrylate.

(6) The film for forming a protective film according to any one of the above (2), wherein the monomer constituting the acrylic polymer (A) contains methyl (meth)acrylate.

(7) The film for forming a protective film according to any one of the above (2), wherein the monomer constituting the acrylic polymer (A) contains methyl acrylate.

(8) The film for forming a protective film according to any one of the above (1), wherein the filler (C) is contained.

(9) A composite film for forming a protective film, comprising a support sheet, and a film for forming a protective film according to any one of the above (1) to (8), which is provided on the support sheet.

(10) A protective film-forming wafer comprising a semiconductor wafer and a protective film obtained by curing a film for forming a protective film according to any one of the above (1) to (8).

In the present invention, there is provided a film for forming a protective film which can be prevented from being formed on a needle on a protective film during pick-up.

Hereinafter, the present invention will be specifically described using the embodiments thereof.

In the present specification, "(meth)acrylic" is used as a term indicating both "acrylic" and "methacrylic", and the same applies to other similar terms. Further, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are values in terms of polystyrene measured by a gel permeation chromatography (GPC) method.

[film for forming a protective film]

The film for forming a protective film of the present invention is formed to protect a protective film of a semiconductor wafer, and the surface hardness of the film after hardening is 55 or more, and the Young's modulus (23 ° C) after hardening is 1.0 × 10 ⁹ Pa or more.

When the film for forming a protective film is less than 55 or the Young's modulus is less than 1.0 × 10 ⁹ Pa, the protective film is easily plastically deformed, and when the wafer is lifted by the needle, the needle mark is easily attached. The surface of the film does not provide the effect of the present invention.

The film for forming a protective film preferably has a Shore D hardness of 58 or more and a Young's modulus (23 ° C) of 2.0 × 10 ⁹ Pa or more, more preferably a Shore D hardness of 62 or more and a Young's modulus (23 ° C). It is 5.0 × 10 ⁹ Pa or more. In the present invention, the Shore D hardness and the Young's modulus are made higher, and even if the semiconductor wafer is picked up with a high pickup force, it is difficult to attach a needle mark to the surface of the protective film.

The upper limit of the D hardness and the Young's modulus (23° C.) is not particularly limited. However, from the viewpoint of preventing the protective film from becoming brittle and easily improving the reliability, the D hardness is preferably 90 or less and the Young's modulus. (23 ° C) is 9.0 × 10 ¹⁰ Pa or less, more preferably, the Shore D hardness is 80 or less and the Young's modulus (23 ° C) is 5.0 × 10 ¹⁰ Pa or less.

The material of the film for forming a protective film of the present invention is not particularly limited, and is usually a material containing a binder resin and a thermosetting component. The binder resin is a component that imparts flexibility and film-forming properties to the protective film and the film for forming a protective film. As the binder resin, an acrylic resin, a polyester resin, a urethane resin, an urethane urethane resin, a polyoxymethylene resin, a rubber-based polymer, a phenoxy resin or the like can be used. The binder resin may be used alone or in combination of two or more.

The thermosetting component is a component for forming a hard protective film on a semiconductor wafer by curing, and is usually made of a thermosetting resin and a thermosetting agent which thermally cures the thermosetting resin. Examples of the thermosetting resin include an epoxy resin, a phenol resin, an amine resin, an unsaturated polyester resin, a polyurethane resin, a polyoxyxylene resin, and a thermosetting polyimide resin. The thermosetting resin and the thermosetting agent may be used alone or in combination of two or more.

The film for forming a protective film of the present invention preferably contains an acrylic polymer (A) as a binder resin and an epoxy-based curable component (B) as a thermosetting component. In the present invention, by using the above components (A) and (B), the reliability of the protective film can be improved and the above-mentioned Shore D hardness and Young's modulus can be easily controlled within a desired range. Therefore, even if the semiconductor wafer is picked up with a high pickup force, it is not easy to protect the additional pin marks on the film.

Hereinafter, the acrylic polymer (A) and the epoxy-based curable property are formed. Sub-paragraph (B) is described in detail.

<Acrylic Polymer (A)>

The acrylic polymer (A) constituting the acrylic resin contains at least a (meth) acrylate monomer as a monomer constituting the acrylic polymer. In other words, the acrylic polymer (A) is obtained by polymerizing a monomer containing at least a (meth) acrylate monomer.

Specific examples of the (meth) acrylate monomer are methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and butyl (meth) acrylate. Ester, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, (alkyl) (meth) acrylate, lauryl (meth) acrylate, etc., alkyl (meth) acrylate having 1 to 18 alkyl carbon atoms; cycloalkyl having 1 to 18 carbon atoms (methyl) Cycloalkyl acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, (meth) acrylate a (meth) acrylate having a cyclic skeleton such as dicyclopentenyloxyethyl ester or quinone imine (meth) acrylate; hydroxymethyl (meth) acrylate; 2-hydroxy ethane (meth) acrylate a hydroxyl group-containing (meth) acrylate such as an ester or 2-hydroxypropyl (meth)acrylate; glycidyl (meth)acrylate; β-methylglycidyl (meth)acrylate; (methyl) Acrylic (3,4-epoxy) Cyclohexyl) methyl (meth) acrylate, 3-epoxy-2-hydroxypropyl acrylate, etc. The epoxy group-containing (meth) acrylate.

And, acrylic acid, methacrylic acid, isaconic acid, vinyl acetate, and c A monomer other than the (meth) acrylate monomer such as a nitrile, styrene, vinyl ether or N-methylol acrylamide can also be used as the monomer constituting the acrylic polymer (A). These monomers may be used alone or in combination of two or more.

The monomer constituting the acrylic polymer (A) preferably contains an alkyl (meth)acrylate in the above monomer, and more preferably an alkyl (meth) acrylate having an alkyl group having 1 to 8 carbon atoms. Base ester. Further, the alkyl (meth)acrylate having an alkyl group having 1 to 8 carbon atoms is preferably 50% by mass or more, more preferably 60 to 95% by mass, based on the total of the monomers constituting the acrylic polymer. More preferably 70 to 90% by mass. Further, the alkyl group having 1 to 8 carbon atoms in the alkyl group is more preferably an alkyl group having 1 to 4 carbon atoms.

Further, in order to easily increase the Shore D hardness and the Young's modulus, the alkyl (meth)acrylate having a carbon number of 1 to 8 preferably contains methyl (meth)acrylate, and the methyl (meth)acrylate is relatively It is more preferably 50 to 80% by mass based on all the monomers constituting the acrylic polymer (A). Further, the (meth)acrylic acid methyl ester is more preferably methyl acrylate, from the viewpoint of improving the adhesion to the semiconductor wafer, improving the adhesion, and improving the handleability of the film for forming a protective film.

The monomer constituting the acrylic polymer (A) further preferably contains a hydroxyl group-containing (meth) acrylate or an epoxy group-containing (meth) acrylate, and further preferably contains the two monomers. By. By using these monomers, the above-mentioned D hardness and Young's modulus can be made appropriate, and the adhesion and adhesion characteristics of the film for forming a protective film to a semiconductor wafer can be easily controlled.

Hydroxy-containing (meth) acrylate relative to constituting acrylic polymerization The total monomer of the body (A) is preferably from 1 to 30% by mass, more preferably from 5 to 25% by mass, still more preferably from 10 to 20% by mass.

Further, the epoxy group-containing (meth) acrylate is preferably from 0.1 to 30% by mass, more preferably from 0.5 to 25% by mass, based on the total of the monomers constituting the acrylic polymer (A), and more preferably 1 to 8 mass%.

The weight average molecular weight (Mw) of the acrylic polymer (A) is preferably 10,000 or more in order to impart flexibility and film-forming properties to the film for forming a protective film. Further, the above weight average molecular weight is more preferably from 15,000 to 1,000,000, still more preferably from 20,000 to 500,000.

Further, the glass transition temperature of the acrylic polymer (A) is preferably -60 to 50 ° C, more preferably -30 to 30 ° C, still more preferably -20 to 20 ° C. Further, the glass transition temperature of the acrylic polymer (A) is a theoretical value obtained by the formula of Fox. By setting the glass transition temperature to the above range, the reliability of the protective film can be improved and the Shore D hardness and the Young's modulus can be easily made good.

The proportion of the acrylic polymer (A) in the total mass (solid content conversion) of the film for forming a protective film is usually from 10 to 80% by mass, preferably from 15 to 50% by mass.

<epoxy hardening component (B)>

The epoxy-based curable component (B) is usually composed of an epoxy-based compound (epoxy resin) as a thermosetting resin and a thermosetting agent.

Specific examples of the epoxy compound are a biphenyl compound, bisphenol A diglycidyl ether or a hydride thereof, an o-cresol novolac epoxy resin, a dicyclopentadiene type epoxy resin, a biphenyl type epoxy resin, Bisphenol A type epoxy tree An epoxy compound having two or more functional groups in the molecule, such as a lipid, a bisphenol F-type epoxy resin, a phenylene skeleton type epoxy resin, or a condensed cyclic aromatic compound having an epoxy group. These may be used alone or in combination of two or more.

The epoxy compound is preferably 45 to 150 parts by mass, more preferably 55 to 120 parts by mass, even more preferably 68 to 110 parts by mass, more preferably 100 parts by mass to the acrylic polymer (A). 75 to 100 parts by mass. When the epoxy-based compound is in the above range, the reliability and the like of the protective film can be improved, and the Shore D hardness and the Young's modulus can be easily adjusted to desired values.

Further, the epoxy compound preferably contains a condensed cyclic aromatic compound (b1) having an epoxy group in the above compound. The condensed cyclic aromatic compound (b1) having an epoxy group means having a condensed polycyclic aromatic hydrocarbon group and an epoxy group, and the epoxy group is bonded to the condensed polycyclic aromatic group directly or through an alkyl ether group. Hydrocarbyl-based compound. The total number of carbon atoms of the condensed polycyclic aromatic hydrocarbon group in the condensed cyclic aromatic compound (b1) is not particularly limited, and is preferably from 8 to 55, more preferably from 12 to 45, still more preferably from 16 to 35. Further, the alkylene ether means a divalent group having an alkylene group and an etheric oxygen atom, and examples thereof include an oxymethylene group and the like.

By using the condensed cyclic aromatic compound (b1) having an epoxy group as the epoxy compound, the Shore D hardness and the Young's modulus of the film for forming a protective film are likely to be high. Further, the film for forming a protective film can be cured in a short time and the strength of the protective film can be increased, so that the reliability of the protective film and the productivity of the wafer with the protective film can be easily improved.

a condensed cyclic aromatic compound having an epoxy group (b1), as a glycidyl ether group bonded to a condensed ring (oxymethylene-bonded epoxy group), for example, a compound represented by the following formula (I) or (II).

However, in the formula (I), CR represents a condensed polycyclic aromatic hydrocarbon group, R ¹ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and m represents an integer of 2 to 6. When R ¹ is an alkyl group, the carbon number thereof is preferably from 1 to 6. And m is preferably 2 to 4.

However, in the formula (II), CR ¹ and CR ² represent a condensed polycyclic aromatic hydrocarbon group, and the condensed polycyclic aromatic hydrocarbon groups may be the same or different, and R ² represents a divalent hydrocarbon group, and the hydrocarbon group Further, the substituents a and R ³ represent an alkyl group having a carbon number of 1 to 10 or a glycidyl ether group, n is an integer of 0 to 3, and p is an integer of 0 to 10. If p is 0, R ² represents a single bond. , q represents an integer from 1 to 3. The carbon number of R ² is preferably from 1 to 6. Further, when R ³ is an alkyl group, the carbon number thereof is preferably from 1 to 6. n is preferably 1 to 2, p is preferably 0 to 4, and q is preferably 1 to 2, wherein p is more preferably 1.

The substituent a of R ² in the formula (II) is exemplified by a phenyl group or a phenyl group having a substituent b. The substituent b is exemplified by an alkyl group having 1 to 6 carbon atoms or a glycidyl ether group, and preferably an alkyl group having 1 to 4 carbon atoms.

When the condensed polycyclic aromatic hydrocarbon group is condensed by two or more aromatic rings, the carbon number of the condensed polycyclic aromatic hydrocarbon group in the above formula (I) or (II) is preferably from 8 to 22, more preferably Good for 10~20. The specific condensed polycyclic aromatic hydrocarbon group is exemplified by a hydrocarbon group composed of a naphthalene ring, an anthracene ring, a phenanthrene ring or a 3,4-benzofluorene ring, and the like, and also based on the viewpoint of the hardenability of the film for forming a protective film. It is preferably a naphthalene ring.

The condensed cyclic aromatic compound having an epoxy group is preferably a compound represented by the formula (II), more preferably a compound represented by the formula (II) having a naphthalene ring. An example of a specific compound represented by the formula (II) having a naphthalene ring is exemplified by 1,1-bis(2,7-diglycidoxy-1-naphthyl)alkane represented by the following formula (III). A compound such as 1-(2,7-diglycidoxy-1-naphthyl)-1-(2-glycidoxy-1-naphthyl)alkane represented by the following formula (IV) A compound or a compound such as 1,1-bis(2-glycidoxy-1-naphthyl)alkane represented by the following formula (V).

However, the general formula (III) ~ (V) in each of those, R ⁴ represents a single bond or a divalent hydrocarbon group which may have a substituent. Further, when two or more kinds of the compounds of the formulae (III) to (V) are used in combination, R ^{4 in} each of the compounds may be the same or different.

R formula (III) ~ (V) of ⁴ Further preferably represented by the following formula (VI) may have the substituent of the divalent hydrocarbon group.

In the above formula (VI), the bonding bond bonded to the upper and lower sides of the carbon is bonded to the naphthyl group, and R ⁵ and R ⁶ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a phenyl group or a substituted group. The phenyl group of the base c. When R ⁵ and R ⁶ are a phenyl group having a substituent c, the substituent c is, for example, an alkyl group having 1 to 10 carbon atoms or a glycidyl ether group, and preferably an alkyl group having 1 to 6 carbon atoms. R ⁵ and R ^{6 are} preferably hydrogen atoms from the viewpoint of curability of the film for forming a protective film. In the above formula (VI), r is 0 to 4, preferably an integer of 0 to 3, and further preferably 1. Further, when r is 0, it means that the structure of the above formula (VI) is a single bond.

Further, among the compounds represented by the general formulae (III) to (V), a compound represented by the formula (III) is preferred, and it is particularly preferred that R ⁴ in the formula (III) is a methylene group (-CH). ₂ -) compounds.

Further, the epoxy equivalent of the condensed cyclic aromatic compound (b1) having an epoxy group is preferably from 120 to 250 g/eq, more preferably from 130 to 180 g/eq. When the epoxy equivalent is within the above range, the curability of the film for forming a protective film is improved, and the Shore D hardness and the Young's modulus are easily made good.

The glass transition temperature of the cured product of the epoxidized cyclic aromatic compound (b1) having an epoxy group is preferably 220 ° C or higher, more preferably 220 to 350 ° C, further preferably 240 to 345 ° C, and most preferably 300 °. 330 ° C. When the glass transition temperature of the cured product of the compound (b1) is in the above range, the film for forming a protective film can be made to have good curability and high strength. Further, it is easy to make the aforementioned D hardness and Young's modulus into good values.

Further, the glass transition temperature of the cured product of the compound (b1) and the other epoxy compound (b2) described later is determined by using a viscoelasticity by hardening a curing agent in the compound (b1) or (b2). Device measurer. The detailed measurement conditions can be described in the examples described later.

The softening point of the condensed cyclic aromatic compound (b1) having an epoxy group is preferably from 60 to 110 ° C, more preferably from 70 to 100 ° C, still more preferably from 80 to 97 ° C. When the softening point of the condensed cyclic aromatic compound having an epoxy group is in the above range, the curability of the film for forming a protective film can be improved, and the above-mentioned Shore D hardness and Young's modulus can be easily made good. Further, the softening point is measured by the method described in the GM method according to JIS K2207:2006, specifically, the method described in the examples described later.

The fused condensed aromatic compound having an epoxy group preferably has a melt viscosity of 1.0 to 25.0 dPa. s, better for more than 2.0dPa. s and 15.0dPa. s below, and further preferably 2.5~7.0dPa. s. When the melt viscosity of the condensed cyclic aromatic compound having an epoxy group is in the above range, the curability of the film for forming a protective film can be improved. Further, the melt viscosity was measured by a capillary rheometer at a measurement temperature of 150 ° C and a measurement frequency of 1 Hz.

Further, the number average molecular weight (Mn) of the condensed cyclic aromatic compound (b1) having an epoxy group is preferably from 200 to 1,000, more preferably from 300 to 900, still more preferably from 400 to 800, most preferably from 450 to 0.45. 750. When the number average molecular weight (Mn) of the condensed cyclic aromatic compound having an epoxy group is in the above range, the curability of the film for forming a protective film can be improved, and further, the above-mentioned Xiao D hardness and Young's mode can be easily obtained. The number becomes a good value.

In the film for forming a protective film, it is preferred to use another epoxy compound (b2) together with the condensed cyclic aromatic compound (b1) having an epoxy group. The other epoxy compound (b2) to be used in combination is exemplified by the above-exemplified epoxy compound other than the condensed cyclic aromatic compound (b1) having an epoxy group, and among them, a bisphenol A type epoxy resin is preferably used. At least one of the dicyclopentadiene type epoxy resins is preferably used.

When a condensed cyclic aromatic compound (b1) having an epoxy group and another epoxy compound (b2) are used, the condensed cyclic aromatic compound (b1) having an epoxy group in the film for forming a protective film and other rings are used. The mass ratio (b1:b2) of the oxygen compound (b2) is preferably from 1:3 to 1:15, more preferably from 1:5 to 1:10. By using two or more epoxy compounds in combination with the above mass ratio, the strength, curability, reliability, and the like of the film for forming a protective film can be improved, and the Shore D hardness and Young's modulus can be easily adjusted to desired. range.

Further, the number average molecular weight of the other epoxy compound (b2) is not particularly limited, but is preferably from 250 to 10,000, preferably from 300 to 3,000, from the viewpoint of the hardenability of the adhesive or the strength or heat resistance after curing. . The epoxy equivalent of the other epoxy compound (b2) is preferably from 100 to 1000 g/eq, more preferably It is 150~800g/eq.

Further, the glass transition temperature of the cured product of the other epoxy compound (b2) is preferably lower than that of the condensed cyclic aromatic compound (b1) having an epoxy group in order to improve adhesion to a semiconductor wafer. 150 to 240 ° C, more preferably 165 to 225 ° C, and even more preferably 170 to 220 ° C.

The thermosetting agent to be used together with the epoxy compound is exemplified by a compound having two or more functional groups reactive with an epoxy group in one molecule. The functional groups thereof are exemplified by a phenolic hydroxyl group, an alcoholic hydroxyl group, an amine group, a carboxyl group, and an acid anhydride. Among these, a phenolic hydroxyl group, an amine group, an acid anhydride, etc. are preferable, and a phenolic hydroxyl group and an amine group are further preferable.

Specific examples of the phenolic curing agent having a phenolic hydroxyl group are polyfunctional phenol resins, bisphenols, novolac type phenol resins, dicyclopentadiene phenol resins, xylose (Xyloc) type phenol resins, and aralkylphenols. Resin. A specific example of the amine-based amine hardener is dicyanodiamine. These may be used alone or in combination of two or more.

The content of the thermal curing agent in the film for forming a protective film is preferably from 0.1 to 100 parts by mass, more preferably from 0.5 to 50 parts by mass, even more preferably from 1 to 20 parts by mass, per 100 parts by mass of the epoxy compound.

In addition, the ratio of the epoxy-based curable component (B) (that is, the total amount of the epoxy-based compound and the thermosetting agent) to the total mass (solid content conversion) of the film for forming a protective film is usually 5 to 60. The mass% is preferably 15 to 40% by mass.

<Filling material (C)>

The film for forming a protective film preferably further contains a filler (C). By containing the filler (C), it is possible to impart moisture resistance and dimensional stability to the protective film, and it is also possible to improve the reliability of the protective film. Furthermore, it is easy to set the Shore D hardness and the Young's modulus to a good value. As the filler (C), an inorganic filler is specifically exemplified. Preferred inorganic fillers are exemplified by powders of cerium oxide, aluminum oxide, talc, calcium carbonate, titanium oxide, iron oxide, cerium carbide, boron nitride, etc., spheroidized beads, single crystal fibers, glass fibers, and the like. Among these, a cerium oxide filler and an alumina filler are preferred, and a cerium oxide filler is more preferred. Further, the above inorganic fillers may be used singly or in combination of two or more.

The content of the filler (C) is preferably from 10 to 70% by mass, more preferably from 40 to 65% by mass, based on the total mass of the film for forming a protective film (in terms of solid content).

Further, the average particle diameter of the inorganic filler is preferably from 0.02 to 20 μm, more preferably from 0.05 to 10 μm. The average particle diameter of the inorganic filler is determined by an electron microscope to measure the long axis diameter of 20 randomly selected inorganic fillers, and the number average particle diameter calculated from the arithmetic mean value thereof.

<hardening accelerator (D)>

The film for forming a protective film may further contain a curing accelerator (D). The film for protective film formation contains the hardening accelerator (D), and the rate of thermal hardening can be adjusted.

As preferred curing accelerators (D), tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, ginseng (dimethylaminomethyl)phenol; 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methyl Imidazoles such as imidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole; tributylphosphine, diphenylphosphine, three An organic phosphine such as phenylphosphine; a tetraphenylboron salt such as tetraphenylphosphonium tetraphenyl borate or triphenylphosphine tetraphenyl borate; These may be used alone or in combination of two or more.

The curing accelerator (D) is contained in the film for forming a protective film in an amount of preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the epoxy compound. By including the curing accelerator (D) in the above range, the film for forming a protective film can have excellent adhesion properties even when exposed to high temperature and high humidity, and can be made high even when exposed to severe conditions. Trustworthiness.

<Colorant (E)>

The film for forming a protective film may further contain a coloring agent (E). By containing the coloring agent (E), infrared rays or the like can be blocked, so that malfunction of the semiconductor device due to infrared rays generated from the surrounding device can be prevented. Further, when the protective film is marked by a laser mark or the like, it is easy to recognize marks such as characters and symbols.

As the colorant, an organic or inorganic pigment or dye is used. As the dye, any dye such as an acid dye, a reactive dye, a direct dye, a disperse dye, a cationic dye or the like can also be used. Further, the pigment is not particularly limited, and the pigment can be appropriately selected and used. Among these, the black paint has a good shielding property against electromagnetic waves or infrared rays, and the visibility by the laser marking method can be further improved. As a black pigment, carbon black, iron oxide, and dioxane can be used. Manganese, aniline black, activated carbon, etc., but are not limited to these. From the viewpoint of improving the reliability of the protective film, carbon black is preferred. The coloring agent (E) may be used alone or in combination of two or more.

The ratio of the content of the colorant (E) to the total mass (in terms of solid content) of the film for forming a protective film is preferably from 0.01 to 10% by mass, more preferably from 0.1 to 5% by mass.

<Coupling agent (F)>

The film for forming a protective film may further contain a coupling agent. The coupling agent has a functional group capable of reacting with an inorganic substance and a functional group reactive with an organic functional group, and can improve the adhesion and adhesion of the film for forming a protective film to the adherend. Further, the aggregability of the protective film can also be improved. The coupling agent is exemplified by a titanate coupling agent, an aluminate coupling agent, a decane coupling agent, and the like, and among these, a decane coupling agent is preferred.

As the decane coupling agent, a compound having a group reactive with a functional group of at least one of the above-described binder resin and a thermosetting resin constituting the thermosetting component can be preferably used. Specific examples of the decane coupling agent are γ-glycidoxypropyltrimethoxydecane, γ-glycidoxypropylmethyldiethoxydecane, and β-(3,4-epoxycyclohexyl). Ethyltrimethoxydecane, γ-(methacryloxypropyl)trimethoxydecane, γ-aminopropyltrimethoxydecane, N-6-(aminoethyl)-γ-amino group Propyltrimethoxydecane, N-6-(aminoethyl)-γ-aminopropylmethyldiethoxydecane, N-phenyl-γ-aminopropyltrimethoxydecane, γ- Ureidopropyltriethoxydecane, γ-mercaptopropyltrimethoxydecane, γ-mercaptopropylmethyldimethoxy Decane, bis(3-triethoxydecylpropyl)tetrasulfane, methyltrimethoxydecane, methyltriethoxydecane, vinyltrimethoxydecane, vinyltriethoxydecane, Imidazolyl decane and the like. These may be used alone or in combination of two or more.

The ratio of the content of the coupling agent to the total mass (in terms of solid content) of the film for forming a protective film is preferably from 0.1 to 10% by mass, more preferably from 0.1 to 3.0% by mass.

<Other additives>

The other additives which may be contained in the film for forming a protective film are not particularly limited, but may be, for example, a crosslinking agent, a compatibilizing agent, a leveling agent, a plasticizer, an antistatic agent, an antioxidant, an ion scavenger, and a gettering. A agent, a chain transfer agent, an energy ray polymerizable compound, a photopolymerization initiator, and the like.

The thickness of the film for forming a protective film is not particularly limited, but is preferably from 3 to 300 μm, more preferably from 5 to 250 μm, still more preferably from 7 to 200 μm.

[Composite sheet for forming a protective film]

The composite sheet for forming a protective film of the present invention includes a support sheet and a film for forming a protective film provided on the support sheet, and the film for forming a protective film can be peeled off from the support sheet.

In the composite sheet for forming a protective film, the film for forming a protective film can be formed in the same shape as the support sheet. Further, the composite sheet for forming a protective film may have a film for forming a protective film to have a shape substantially the same as or similar to a circular shape, and the support sheet is formed to be larger than the protective film. The composition of a film having a larger size (hereinafter also referred to as "pre-formed structure").

The support sheet is a film for supporting a film for forming a protective film, and is provided with a substrate. Examples of the substrate include, for example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, and polyethylene terephthalate. Ester film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate copolymer film, ionic polymer resin film, ethylene / (methyl) An acrylic copolymer film, an ethylene/(meth)acrylate copolymer film, a polystyrene film, a polycarbonate film, a polyimide film, a fluororesin film, and the like. Further, a laminate film obtained by laminating two or more layers of the film or a film obtained by using the film may be used as a substrate.

Further, the support film may be composed of a single substrate, but may have various layers other than the substrate.

For example, the support sheet may be a release film having a release agent layer on the side of the substrate on which the film for protective film formation is provided. The release agent used for the release treatment is, for example, an alkyd type, a polyoxymethylene type, a fluorine type, an unsaturated polyester type, a polyolefin type, a wax type, or the like, and an alkyd type, a polyoxymethylene type, or a fluorine type release agent is used. It is preferred to have heat resistance.

Further, in the composite sheet for forming a protective film, a release film may be further bonded to the surface of the film for forming a protective film opposite to the side on which the support sheet is provided, and the film for forming a protective film may be protected or supported by the release film.

Moreover, it is also possible to use an adhesive layer on the substrate and the substrate. The adhesive sheet serves as a support sheet. In this case, the film for forming a protective film is provided on the adhesive layer. According to this configuration, in particular, when the wafer is singulated together with the film for forming a protective film or the protective film on the support sheet, the wafer or the wafer can be appropriately fixed by the support sheet.

Further, by using the adhesive layer as the re-peelable adhesive layer, it is preferable that the film for forming a protective film or the protective film can be easily separated from the support film. The re-adhesive adhesive layer may be a weak adhesive having a degree of adhesion to a film for forming a peelable protective film, or an energy ray-curable one which reduces the adhesive force by irradiation with an energy ray. Specifically, the re-peelable adhesive layer can be variously used in various adhesives (for example, rubber, acrylic, polyoxyl, urethane, vinyl ether, etc.) It is formed by an adhesive for surface irregularities, an energy ray-curable adhesive, an adhesive containing a thermal expansion component, and the like.

When the energy ray-curable re-peelable adhesive layer is used, when the composite film for forming a protective film is formed into a pre-formed structure, the region of the film for forming a protective film is irradiated with energy rays in advance to reduce the adhesiveness. On the one hand, it is also possible to perform energy beam irradiation on other regions, and to maintain a high adhesive force for the purpose of, for example, the attachment of a ring frame or the like. When the energy ray irradiation is not performed in other regions, the energy ray shielding layer may be provided by printing a region corresponding to, for example, the support sheet corresponding to the other regions, and the energy ray irradiation may be performed from the support sheet side. Moreover, in order to obtain the same effect, it is also possible to form a region in which the film for protective film formation on the adhesive layer of the adhesive sheet is laminated, and further to form a re-peelable adhesive layer having substantially the same shape as the film for forming a protective film. .

When the film for forming a protective film is not formed in advance, it may be provided on the outer surface of the surface of the film for forming a protective film (the surface in contact with the adherend), and another jig for fixing the ring frame or the like may be provided. Adhesive tape on the agent layer or on both sides. When the film for forming a protective film is formed into a pre-formed structure, a region in which the film for forming a protective film is not laminated in the outer peripheral portion of the support sheet may be provided, and an adhesive layer or a double-sided layer for fixing other jigs such as a ring frame may be provided. Adhesive tape.

The film for forming a protective film can be formed by applying a protective film forming composition obtained by mixing the above components in a suitable solvent or in a solvent-free manner to a support sheet at an appropriate ratio, followed by drying. Further, the protective film-forming composition may be applied onto a process film different from the support sheet, dried to form a film, and formed by appropriately transferring onto a support sheet. The process film is then removed and used as the release film described above.

[How to use the film for forming a protective film]

The film for forming a protective film is attached to an adherend such as a semiconductor wafer or a semiconductor wafer, and then thermally cured to be used as a protective film. When the film for forming a protective film is attached to the adherend as a composite sheet for forming a protective film, first, the release film is peeled off as necessary, and then, a laminate of the film for forming a protective film and the support sheet is used as a protective film. The film for formation is brought into contact with the adherend, and after being attached to the adherend, a suitable support sheet is peeled off from the film for forming a protective film as necessary.

Further, the film for forming a protective film is not particularly limited, but may be cured by, for example, heating at 100 to 180 ° C for 30 to 180 minutes.

In the following, an example in which a film for forming a protective film is used for producing a film with a protective film for protecting the back surface of a semiconductor wafer is described. However, the present invention is not limited to the examples described below.

In the method, first, the film for forming a protective film is laminated on the back surface of the semiconductor wafer. For example, when a composite sheet for forming a protective film is used, a laminate of a film for forming a protective film and a substrate sheet is attached to the back surface of the semiconductor wafer. Subsequently, the film for forming a protective film laminated on the semiconductor wafer is thermally cured to form a protective film on the entire surface of the wafer.

The support sheet may be peeled off from the film for forming a protective film before the heat curing, but the peeling may be performed after the heat curing of the protective film, or may be performed after the cutting. Further, when the peeling of the support sheet is performed after the cutting, the support sheet can function as a cut sheet. When the support sheet functions as a dicing sheet, it is preferably the above-mentioned adhesive sheet.

Further, the semiconductor wafer may be a germanium wafer, and may be a compound semiconductor wafer such as gallium/arsenic. Further, the semiconductor wafer may have a thickness of 50 to 500 μm, such as a circuit formed on the surface thereof and appropriately ground on the back surface.

Next, the laminate of the semiconductor wafer and the protective film is cut together with each circuit formed on the surface of the wafer. The dicing is performed by cutting the wafer together with the protective film, and the laminated system of the semiconductor wafer and the protective film is diced by a plurality of wafers by dicing, and becomes a semiconductor wafer having a protective film on the back surface (attached) Protective film wafer).

Wafer cutting is performed in a conventional manner using a cut sheet. Here, protection When the support sheet used in film formation is not peeled off, the support sheet itself can also be used as a cut sheet. Further, when the support sheet is peeled off, a conventional cut sheet may be attached to the surface of the protective film side of the laminate of the semiconductor wafer and the protective film before the dicing.

At the end of the dicing, the surface of the wafer on which the protective film is diced is lifted up from the surface on the side of the dicing sheet by a needle, and picked up by a wide-purpose means such as a jig to recover the wafer with the protective film. In the present invention, since the Shore D hardness and the Young's modulus after curing of the film for forming a protective film are at a specific value or more, it is possible to prevent the pick-up marks from sticking to the protective film during pick-up.

In the above description, an example in which the film for forming a protective film is thermally cured before dicing is exemplified, but the film for forming a protective film may be thermally cured after the semiconductor wafer is diced and before being picked up. Further, the wafer with the protective film can also be thermally hardened when mounted face down or after mounting.

[wafer with protective film]

The film with a protective film of the present invention is obtained by, for example, a semiconductor wafer obtained by the above-described production method and a protective film provided on the semiconductor wafer, and the protective film is obtained by curing the film for forming a protective film. The protective film is usually laminated on the back side of the wafer to protect the back side of the wafer. The wafer with a protective film of the present invention can be mounted on a substrate or the like by a face-down method to manufacture a semiconductor device. Further, the wafer with the protective film can be fabricated by following a die pad portion or another member such as a semiconductor wafer (on the wafer mounting portion).

[Examples]

Hereinafter, the present invention will be described in further detail based on examples, but the present invention is not limited by the examples.

The measurement method and evaluation method of the present invention are as follows.

[Xiao's D hardness]

The film for forming a protective film was laminated so as to have a thickness of 6 mm or more, and then hardened by heating at 130 ° C for 2 hours. The Shore D hardness of the surface of the film for forming a cured protective film was measured at a measurement temperature of 23 ° C using a constant pressure loader (CL-150, manufactured by Polymer Timer Co., Ltd.).

[Young's modulus]

The film for forming a protective film was cured by heating at 130 ° C for 2 hours. The cured film for forming a protective film was measured for Young's modulus at a test speed of 200 mm/min in accordance with JIS K 7127 at 23 ° C.

[Glass transfer temperature after hardening of epoxy compound]

2 g of 2-phenyl-4,5-dihydroxymethylimidazole (CURAZOLE 2PHZ, manufactured by Shikoku Chemicals Co., Ltd.) as a curing agent was added to 100 g of the epoxy compound at a curing temperature of 160 ° C and a hardening time of 120 minutes. The epoxy compound is cured. Next, the cured product of the epoxy compound was cut into a short strip having a width of 4.5 mm, a length of 20.0 mm, and a thickness of 0.18 mm to prepare a test piece. Subsequently using a viscoelasticity measuring device (TAinstruments DMAQ800), the tan δ (the ratio of the loss elastic modulus to the storage elastic modulus) of the test piece was measured in a tensile mode at a frequency of 11 Hz and a temperature increase rate of 3 ° C/min at 0 to 350 ° C under atmospheric pressure. The temperature at which tan δ shows the maximum value in this temperature range was read as the glass transition temperature (Tg) of the cured product of the epoxy compound.

[Softening point of epoxy compound]

According to JIS K 2207:2006, a ball of a certain weight is placed in the center of the support ring in a bath of water or glycerin, and after the bath temperature is raised at a predetermined speed, the temperature at which the sample hangs due to the weight of the ball is measured as a softening point (ring and ball method).

[Fused viscosity of epoxy compound]

The melt viscosity of the epoxy compound was determined by a capillary rheometer (manufactured by Shimadzu Corporation, CFT-100D) under the conditions of a measurement temperature of 150 ° C and a measurement frequency of 1 Hz.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]

The weight average molecular weight (Mw) and the number average molecular weight (Mn) were determined by a gel permeation chromatography (GPC) method under the following measurement conditions, and were obtained in terms of standard polystyrene.

Measuring device: The high-speed GPC device "HLC-8120GPC" manufactured by TOSOH Co., Ltd., "TSKguard column H _XL -H", "TSKGel GMH _XL ", "TSK GelG2000 H _XL " (all of which are TOSOH shares) Co., Ltd.) is measured in this order.

Column temperature: 40 ° C, feed rate: 1.0 mL / min, detector: differential refractometer

[Needle mark check when picking up]

First, the release film was peeled off from the composite sheet for forming a protective film obtained in each of the examples and the comparative examples. Then, using a film laminator (Adwill RAD-3600F/12, manufactured by LINTEC Co., Ltd.), the exposed film for forming a protective film was formed to face the polished surface of the #2000-polished silicon wafer (200 mm diameter, thickness: 280 μm). A composite sheet for forming a protective film is attached to the wafer. At this time, the temperature at which the wafer was placed was heated to 70 °C.

Then, the composite sheet for protective film formation was further peeled off from the support sheet, and then heated at 130 ° C for 2 hours to cure the film for forming a protective film to form a protective film on the tantalum wafer. Subsequently, an adhesive sheet (Adwill D-676H, manufactured by LINTEC Co., Ltd.) as a dicing sheet was attached to the side of the protective film, and cut into a size of 5 mm × 5 mm using a dicing apparatus (DFD651, manufactured by DISCO Co., Ltd.) to be twinned. The circle is singulated with the protective film.

Next, UV irradiation was carried out under irradiation conditions of 230 mW/cm ² and a cumulative light amount of 170 mJ/cm ^{2 to} cure the adhesive layer of the adhesive sheet by UV irradiation, and then a pick-up test was carried out to confirm the presence or absence of a needle mark. In the pick-up test, a needle No. 5 was placed on a push-pull force meter (MODEL-RE, manufactured by Aiki Chemical Co., Ltd.), and the portion of the cut sheet that was in contact with the semiconductor wafer to be picked up was lifted from the side of the cut sheet by 1.5. In mm. Those who had no needle marks on the protective film were evaluated as A, and those with needle marks were evaluated as B.

[Composition for forming a protective film]

The components constituting the film for forming a protective film in the examples and the comparative examples are as follows.

(acrylic copolymer)

Acrylic polymer 1 : an acrylic polymer obtained by copolymerizing 8 parts by mass of butyl acrylate, 70 parts by mass of methyl acrylate, 17 parts by mass of 2-hydroxyethyl acrylate, and 5 parts by weight of glycidyl methacrylate ( Polymerization average molecular weight: 300,000, glass transition temperature: 0 ° C)

Acrylic polymer 2: an acrylic polymer obtained by copolymerizing 15 parts by mass of butyl acrylate, 65 parts by mass of methyl acrylate, 10 parts by mass of 2-hydroxyethyl acrylate, and 10 parts by weight of glycidyl methacrylate ( Polymerization average molecular weight: 400,000, glass transition temperature: -1 ° C)

Acrylic polymer 3: an acrylic polymer obtained by copolymerizing 55 parts by mass of butyl acrylate, 10 parts by mass of methyl acrylate, 15 parts by mass of 2-hydroxyethyl acrylate, and 20 parts by weight of glycidyl methacrylate ( Polymerization average molecular weight: 800,000, glass transition temperature: -28 ° C)

(epoxy compound)

Epoxy compound 1:1,1-bis(2,7-diglycidoxy-1-naphthyl)methane (glass transition temperature of hardened material: 326 ° C, softening point: 92 ° C, melting Viscosity: 4.5dPa. s, number average molecular weight: 550, epoxy equivalent: 160 g / eq)

Epoxy compound 2: bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER828, glass transition temperature of cured product: 180 ° C, number average molecular weight: 370, epoxy equivalent: 184 to 194 g / eq)

Epoxy compound 3: Dicyclopentadiene type epoxy resin (made by DIC Co., Ltd., EPICLON HP-7200HH, glass transition temperature of cured product: 210 ° C, softening point: 88 ° C, melt viscosity: 8 dPa.s, number Average molecular weight: 760, epoxy equivalent: 275~280g/eq)

Thermal hardener: dicyanodiamine (made by ADEKA Co., Ltd., ADEKA HARDNER 3636AS)

Hardening accelerator: 2-phenyl-4,5-dihydroxymethylimidazole (CURAZOLE 2PHZ, manufactured by Shikoku Chemical Industry Co., Ltd.)

Inorganic filler: cerium oxide filler (fused silica filler, average particle size 8μm)

Colorant: Carbon Black (Mitsubishi Chemical Co., Ltd., MA600B)

(coupling agent)

Coupling agent 1: decane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., X-41-1056)

Coupler 2: decane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-403)

Coupler 3: decane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403)

Examples 1 to 4 and Comparative Examples 1 to 4

In each of the examples and the comparative examples, a composition for forming a protective film having the formulation shown in Table 1 was applied to a release-treated surface of a release film (SP-PET 38,031, manufactured by LINTEC Co., Ltd., thickness: 38 μm). The diluted solution obtained by diluting the ethyl ketone (solid content concentration: 61% by mass) was applied to a dried thickness of 25 μm by a knife coater, followed by drying at 120 ° C for 3 minutes to form a film for forming a protective film on the release film. .

Then, on the film for forming a protective film, a support sheet (SP-PET381130, thickness: 38 μm, manufactured by LINTEC Co., Ltd.) was laminated to obtain a three-layer structure composed of a release film, a film for forming a protective film, and a support sheet. A composite sheet for forming a protective film.

In the above Examples 1 to 4, by making the D hardness and the Young's modulus both high, no needle marks were observed during the pick-up test, and it was possible to manufacture. A wafer with a protective film of good performance. On the other hand, in Comparative Examples 1 to 4, since at least one of the Shore D hardness and the Young's modulus was a low value, it was found that a needle mark was observed during the pick-up test, and a wafer with a protective film having good performance could not be manufactured. .

Claims (10)

A film for forming a protective film for forming a protective film for protecting a semiconductor wafer, characterized in that the surface hardness of the film after hardening is 55 or more, and the Young's modulus (23 ° C) after hardening is 1.0. ×10 ⁹ Pa or more. The film for forming a protective film according to claim 1, which comprises an acrylic polymer (A) and an epoxy curable component (B). The film for forming a protective film according to claim 2, wherein the epoxy-based curable component (B) is a condensed cyclic aromatic compound (b1) having an epoxy group. The film for forming a protective film according to claim 3, wherein the condensed cyclic aromatic compound (b1) having an epoxy group is a compound represented by the following formula (I) or (II), (In the formula (I), CR represents a condensed polycyclic aromatic hydrocarbon group, R ¹ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and m represents an integer of 2 to 6) (In the formula (II), CR ¹ and CR ² represent a condensed polycyclic aromatic hydrocarbon group, and the condensed polycyclic aromatic hydrocarbon groups may be the same or different, and R ² represents a divalent hydrocarbon group. The hydrocarbon group may have a substituent, R ³ represents an alkyl group having a carbon number of 1 to 10 or a glycidyl ether group, n represents an integer of 0 to 3, and p is an integer of 0 to 10. If p is 0, R ² represents a single bond. , q represents an integer from 1 to 3). The film for forming a protective film according to any one of claims 2 to 4, wherein the monomer constituting the acrylic polymer (A) is an alkyl (meth)acrylate having an alkyl group and having 1 to 8 carbon atoms. The film for forming a protective film according to any one of claims 2 to 5, wherein the monomer constituting the acrylic polymer (A) contains methyl (meth)acrylate. The film for forming a protective film according to any one of claims 2 to 6, wherein the monomer constituting the acrylic polymer (A) contains methyl acrylate. The film for forming a protective film according to any one of claims 1 to 7, which contains a filler (C). A composite sheet for forming a protective film, comprising a support sheet and a film for forming a protective film according to any one of claims 1 to 8 which is provided on the support sheet. A protective film-forming wafer comprising a semiconductor wafer and a protective film obtained by curing a film for forming a protective film according to any one of claims 1 to 8 which is provided on the semiconductor wafer.