KR102110105B1 - Protective-membrane-forming film - Google Patents

Abstract

The film for forming a protective film according to the present invention is a film for forming a protective film for forming a protective film for protecting a semiconductor chip, wherein the film for forming a protective film includes (A) an acrylic polymer, (B) an epoxy curable component, and (C) a filler. And (A) the monomer constituting the acrylic polymer contains an epoxy group-containing monomer in a proportion of 8% by mass or less of the total monomers, and (A) the glass transition temperature of the acrylic polymer is -3 ° C or higher, and The gross value measured by JIS Z 8741 of at least one surface of the protective film obtained by curing the protective film forming film is 20 or more.

Description

Protective film forming film {PROTECTIVE-MEMBRANE-FORMING FILM}

The present invention relates to, for example, a film for forming a protective film used to protect the back surface of a semiconductor chip.

Conventionally, semiconductor devices using a mounting method called a face-down method have been manufactured. In the face-down method, the semiconductor chip is protected by a protective film because the surface of the chip on which an electrode such as a bump is formed is bonded to a substrate or the like and the back surface of the chip is exposed. In addition, marks, characters, and the like are printed on the protective film by laser printing or the like on the back surface of the semiconductor chip (hereinafter referred to as a "chip with a protective film") protected by the protective film.

Although the protective film was formed by, for example, resin coating or the like, recently, for example, as disclosed in Patent Document 1, in order to secure uniformity of the film thickness, the sheet for forming a protective film is continuously put into practical use. Is becoming. The sheet for forming a protective film is formed by forming a film for forming a protective film containing a thermosetting component containing an epoxy resin or the like and a binder polymer component containing an acrylic polymer or the like on the support sheet.

On the other hand, it is known variously as an adhesive film used for a semiconductor, for example, Patent Document 2, an adhesive film used for a semiconductor package, etc., separated from each other in the B-stage state, the resin A having an elastic modulus of 3500 to 10000 GPa, and an elastic modulus of 1 It is disclosed that a mixture of resin B to 3000 MPa is an essential component. In the adhesive film of Patent Document 2, for example, an epoxy resin is used as the resin A, and an acrylic rubber that is a copolymer of a methacrylic acid ester and acrylonitrile is used as the resin B.

Japanese Patent Publication No. 2002-280329 Japanese Patent Publication No. 2001-220556

When the protective film of the semiconductor chip is formed from the sheet for forming a protective film disclosed in Patent Literature 1, the chip provided with the protective film may be lifted or peeled off at the junction between the chip and the protective film or cracks in the protective film due to long-term use. Problems such as occurrence are likely to occur, and reliability may be poor. Further, as disclosed in Patent Literature 2, if a composition in which two components are phase-separated is converted to a protective film for a chip, the reliability of the chip with the protective film may be improved, but recognition of characters, etc. by laser printing A separate problem arises that this is easy to get worse.

The present invention has been made in view of the above problems, and it is possible to obtain a chip having a highly reliable protective film, and to provide a film for forming a protective film capable of forming a protective film excellent in character recognition by laser printing. Make it a task.

As a result of repeated studies in order to solve the above problems, the present inventors focused on the acrylic polymer of the resin for forming a protective film, and while containing the epoxy group-containing monomer in the monomer constituting the acrylic polymer, the blending ratio thereof was within a predetermined range. It was found that the above-mentioned problems can be solved by adjusting the glass transition temperature of the acrylic polymer to a predetermined range while adjusting to the following, thereby completing the present invention.

That is, the present invention provides the following (1) to (8).

(1) a film for forming a protective film for forming a protective film for protecting a semiconductor chip,

The film for forming a protective film contains (A) an acrylic polymer, (B) an epoxy-based curable component, and (C) a filler,

(A) while the monomer constituting the acrylic polymer contains an epoxy group-containing monomer in a proportion of 8% by mass or less of the total monomers, and (A) the glass transition temperature of the acrylic polymer is -3 ° C or higher,

A film for forming a protective film having a gross value of 20 or more as measured by JIS Z 8741 on at least one surface of the protective film obtained by curing the film for forming a protective film.

(2) The film for forming a protective film according to (1) above, wherein the glass transition temperature of the acrylic polymer (A) is 6 ° C or lower.

(3) The film for forming a protective film according to (1) or (2) above, wherein the monomer constituting the acrylic polymer (A) further comprises an alkyl (meth) acrylate.

(4) (A) Any one of (1) to (3) above, wherein the monomer constituting the acrylic polymer contains a (meth) acrylic acid alkyl ester having 4 or more carbon atoms in the alkyl group at a proportion of 12% by mass or less of the total monomers. The film for forming the protective film described.

(5) The film for forming a protective film according to the above (4), wherein the alkyl group having 4 or more carbon (meth) acrylate alkyl ester is (meth) acrylate butyl.

(6) The film for forming a protective film according to any one of (1) to (5) above, wherein the content of the filler (C) is 50% by mass or more of the film for forming a protective film.

(7) The film for forming a protective film according to any one of (1) to (6) above, which further contains (D) a colorant.

(8) A chip having a protective film, comprising a semiconductor chip and a protective film formed on the semiconductor chip,

While the protective film is formed by curing the film for forming a protective film, the film for forming a protective film contains (A) an acrylic polymer, (B) an epoxy-based curable component, and (C) a filler,

(A) while the monomer constituting the acrylic polymer contains an epoxy group-containing monomer in a proportion of 8% by mass or less of the total monomers, and (A) the glass transition temperature of the acrylic polymer is -3 ° C or higher,

The protective film is a chip having a protective film having a gross value of 20 or more as measured by JIS Z 8741 on a surface opposite to the surface on the semiconductor chip side.

In the present invention, it is possible to provide a film for forming a protective film capable of forming a protective film having a highly reliable protective film and being capable of forming a protective film excellent in character recognition by laser printing.

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

In addition, in this specification, "(meth) acrylic" is used as a term showing both "acrylic" and "methacryl," and the same applies to other similar terms.

[Film for forming protective film]

The film for forming a protective film according to the present invention is a film for forming a protective film for protecting a semiconductor chip, and contains at least (A) an acrylic polymer, (B) an epoxy-based curable component, and (C) a filler.

<(A) Acrylic polymer>

(A) The acrylic polymer is a component that provides flexibility and film-forming properties to a protective film and a film for forming a protective film, and is obtained by copolymerizing an epoxy group-containing monomer and another monomer, and the ratio of the epoxy group-containing monomer is (A). It is 8 mass% or less among all the monomers which comprise an acrylic polymer. Specifically, the monomers constituting the acrylic polymer (A) include at least one epoxy group-containing monomer selected from epoxy group-containing (meth) acrylic acid esters and non-acrylic epoxy group-containing monomers, and various (meth) acrylic acid esters having no epoxy group, And / or non-acrylic epoxy group-free monomers. In this case, when the epoxy group-containing monomer contains only a non-acrylic epoxy group-containing monomer, the monomer constituting the acrylic polymer contains various (meth) acrylic acid esters having no epoxy group.

When the proportion of the epoxy group-containing monomer is more than 8% by mass, the compatibility of the cured product of the component (B) is improved, the phase-separated structure described later becomes difficult to form, and the reliability of the chip with the protective film is lowered. On the other hand, if the acrylic polymer (A) does not contain an epoxy group-containing monomer at all in the constituent monomers, the deterioration of the gross value of the protective film due to the progress of the phase separation is excessively decomposed, making it difficult to make the gross value within the range described later. Lose. That is, if the epoxy group-containing monomer is not included at all, minute unevenness due to the progress of phase separation occurs on the surface of the protective film, and as a result, scattering of reflected light at the surface of the protective film is caused, so the gross value becomes small and the laser printing part Recognition decreases.

From these viewpoints, the content of the epoxy group-containing monomer is preferably 0.1% by mass or more, and more preferably 1% by mass or more, of the total mass of all monomers. Moreover, it is especially preferable that it is 3 mass% or more in order to further improve reliability while continuing to make the gross value favorable. Moreover, it is preferable that content of the epoxy group containing monomer is 6 mass% or less of the whole monomer of (A) acrylic copolymer.

Examples of the epoxy group-containing (meth) acrylic acid ester include glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, (3,4-epoxycyclohexyl) methyl (meth) acrylate, and 3 -Epoxycyclo-2-hydroxypropyl (meth) acrylate etc., As a non-acrylic epoxy group containing monomer, glycidyl crotonate, allyl glycidyl ether, etc. are mentioned, for example. As the epoxy group-containing monomer, an epoxy group-containing (meth) acrylic acid ester is preferable.

(A) Other monomers in the acrylic polymer include (meth) acrylic acid alkyl esters and other (meth) acrylic acid derivatives.

(A) It is preferable that the monomer which comprises an acrylic polymer contains (meth) acrylic-acid alkylester as said other monomer. This makes it easy to adjust the glass transition temperature of the acrylic polymer (A) by increasing or decreasing the number of carbon atoms of the (meth) acrylic acid alkyl ester, or by combining (meth) acrylic acid alkyl esters of different carbon numbers. It is preferable that (meth) acrylic-acid alkylester is 50 mass% or more of all the monomers which comprise (A) acrylic polymer, and it is more preferable that it is 70 mass% or more. Moreover, it is preferable that (meth) acrylic-acid alkylester is 92 mass% or less of the whole monomer which comprises (A) acrylic polymer.

As the (meth) acrylic acid alkyl ester, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) The alkyl group having 1 to 18 carbon atoms, such as isooctyl acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, etc. And (meth) acrylic acid alkyl esters.

(A) The monomer constituting the acrylic polymer is 12% by mass or less of the (meth) acrylic acid alkyl ester of the (meth) acrylic acid alkyl ester, wherein the alkyl group has 4 or more carbon atoms in the (meth) acrylic acid alkyl ester. It is desirable to contain it in an amount. Thereby, it becomes easy to make a gross value more favorable, making a glass transition temperature into -3 degreeC or more continuously. In order to improve reliability while keeping the gross value satisfactory, the content of the (meth) acrylic acid alkyl ester having 4 or more carbon atoms in the alkyl group is more preferably 1 to 12% by mass, still more preferably 5 to 12% by mass. . Moreover, as the (meth) acrylic acid alkyl ester having 4 or more carbon atoms in the alkyl group, butyl (meth) acrylate is preferable.

Moreover, it is preferable that the monomer which comprises (A) acrylic polymer contains (meth) acrylic-acid alkylester whose alkyl group has 3 or less carbon atoms in the said (meth) acrylic-acid alkylester. By containing the (meth) acrylic acid alkyl ester having 3 or less carbon atoms in the alkyl group, it is easy to make the glass transition temperature of the acrylic polymer (A) to -3 ° C or higher, as described later, while still improving thermal stability and the like. From these viewpoints, the (meth) acrylic acid alkyl ester having 3 or less carbon atoms in the alkyl group is preferably 50% by mass or more, and more preferably 60% by mass or more, of all monomers constituting the acrylic polymer (A). Moreover, it is preferable that (meth) acrylic-acid alkylester whose alkyl group has 3 or less carbon atoms is (A) 90 mass% or less of all the monomers which comprise an acrylic polymer. In addition, as the (meth) acrylic acid alkyl ester having 3 or less carbon atoms in the alkyl group, methyl (meth) acrylate or ethyl (meth) acrylate is preferable, and methyl (meth) acrylate is more preferable.

Moreover, it is preferable that the monomer which comprises (A) acrylic polymer contains another hydroxyl-containing (meth) acrylic acid ester as a (meth) acrylic acid derivative. When a hydroxyl group is introduced into the acrylic copolymer by a hydroxyl group-containing (meth) acrylic acid ester, control of adhesion to a semiconductor chip and adhesion properties becomes easy. Examples of the hydroxyl group-containing (meth) acrylic acid ester include hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and 2-hydroxypropyl (meth) acrylate.

The hydroxyl group-containing (meth) acrylic acid ester is preferably 1 to 30% by mass, more preferably 5 to 25% by mass, and even more preferably 10 to 20% by mass, of all monomers constituting the acrylic polymer (A). Do.

In addition, the monomer constituting the acrylic polymer (A) may include, as another monomer, a non-acrylic epoxy group-free monomer such as styrene, ethylene, vinyl ether, and vinyl acetate.

(A) The weight-average molecular weight (Mw) of the acrylic polymer is preferably 10,000 or more in order to provide flexibility and film-forming properties to the film for forming a protective film, and to easily make the gross value to be described later 20 or more. . In addition, the weight average molecular weight is more preferably 15,000 to 1,000,000, and more preferably 20,000 to 500,000. The weight average molecular weight (Mw) can be measured according to the method of Examples described later.

In the present invention, the acrylic polymer (A) has a glass transition temperature (Tg) of -3 ° C or higher. When the glass transition temperature is less than -3 ° C, the mobility of the acrylic polymer (A) is not sufficiently suppressed, and the protective film tends to deform due to thermal history, and the reliability of the chip with the protective film cannot be sufficiently improved. In the present invention, the glass transition temperature of the acrylic polymer (A) is a theoretical value obtained from the equation of Fox.

Moreover, it is preferable that the glass transition temperature of (A) acrylic polymer is 6 degrees C or less. When the glass transition temperature is 6 ° C or less, the gross value to be described later can be improved, and the printability can be improved. Although this reason is not necessarily obvious, it is estimated that it is because the surface shape of the protective film after hardening is smoothed because the acrylic polymer (A) has moderate mobility.

In the film for forming a protective film, since the epoxy group-containing monomer is suppressed in a small amount, the phase in which the (A) component is high and the phase in which the cured product of the component (B) is large in the protective film is easily phase-separated is easily separated. Reliability is improved. This is presumed to be because the stress caused by the temperature change after the chip mounting is subjected to the temperature change is less likely because the flexible (A) -rich phase relieves the peeling of the protective film due to the stress. In addition, in the phase separation in the protective film-forming film (that is, the protective film) after thermal curing, it is preferable that the phase with many (A) forms a continuous phase. Thereby, the effect of improving the reliability mentioned above can be further improved.

The phase having many (A) and many phases of the cured product of (B) can be determined by observing which substance is the main component of the phase from a measurement chart of which phase, for example, by Raman scattering spectroscopy. In addition, when the size of the phase-separated structure is less than or equal to the resolution of Raman spectroscopy, the hardness of the tapping mode measurement of the SPM (scanning probe microscope) is used as an index. It can be estimated that this (A) component is a large phase. Therefore, in the present invention, it is possible to confirm whether or not a phase separation structure is formed by performing Raman scattering spectroscopy or SPM observation on the protective film obtained by curing the protective film forming film.

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

<(B) Epoxy-based curable component>

(B) The epoxy-based curable component is a component for forming a hard protective film on a semiconductor chip by curing, and usually contains an epoxy-based compound and a thermosetting agent.

In the film for forming a protective film, the epoxy curable component (B) is preferably 250 parts by mass or less, more preferably 150 parts by mass or less, and even more preferably 100 parts by mass with respect to 100 parts by mass of the acrylic polymer (A). Less than wealth. Moreover, (B) epoxy-type curable component is (A) It is 20 mass parts or more with respect to 100 mass parts of acrylic polymers, More preferably, it is 40 mass parts or more, More preferably, it is 60 mass parts or more.

(B) By setting the content of the epoxy-based curable component in the above range, sufficient adhesiveness to an adherend such as a semiconductor chip is obtained, and the peeling force with the supporting sheet described later becomes appropriate, and the supporting sheet is used for forming a protective film. A peeling defect or the like when peeling from the film can also be prevented. In addition, as described above, by limiting the compounding amount of the component (B) to a range equal to or less than a predetermined upper limit, the phase with many components (A) tends to become a continuous phase, and the reliability of the semiconductor chip can be enhanced, and the gross value is also increased. It becomes easy to improve.

In addition, (B) The epoxy-based curable component is a proportion of the total mass (in terms of solid content) of the film for forming a protective film, and is usually about 5 to 60% by mass, preferably about 10 to 40% by mass.

As an epoxy compound, a conventionally well-known epoxy compound can be used. Specifically, a biphenyl compound, bisphenol A diglycidyl ether or a hydrogenated product thereof, orthocresol novolac epoxy resin, dicyclopentadiene type epoxy resin, biphenyl type epoxy resin, bisphenol A type epoxy resin, bisphenol F type Epoxy resins, phenylene skeleton-type epoxy resins, and the like, and epoxy compounds having two or more functionalities in the molecule. These can be used alone or in combination of two or more.

The thermosetting agent functions as a curing agent for the epoxy compound. As a preferable thermosetting agent, the compound which has 2 or more functional groups which can react with an epoxy group in 1 molecule is mentioned. Examples of the functional group include phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, carboxyl groups and acid anhydrides. Among these, phenolic hydroxyl group, amino group, acid anhydride, etc. are mentioned preferably, and phenolic hydroxyl group and amino group are more preferable.

Specific examples of the phenolic curing agent having a phenolic hydroxyl group include polyfunctional phenolic resins, biphenols, novolac-type phenolic resins, dicyclopentadiene-based phenolic resins, xylotype-type phenolic resins, and aralkylphenolic resins. Dicyandiamide is mentioned as a specific example of the amine-type hardener which has an amino group. These can be used individually by 1 type or in mixture of 2 or more types.

Moreover, it is preferable that content of a thermosetting agent is 0.1-100 mass parts with respect to 100 mass parts of epoxy compounds, It is more preferable that it is 0.5-50 mass parts, It is still more preferable that it is 1-20 mass parts. By making the content of the thermosetting agent more than the above lower limit, the component (B) is cured, and the adhesion with the adherend becomes easy to be obtained. Moreover, by setting it below the said upper limit, the moisture absorption rate of the film for protective film formation is suppressed, and it becomes easy to make the reliability of a semiconductor device favorable.

<(C) Filler>

(C) The filler is a component that imparts moisture resistance, dimensional stability, and the like to the protective film, and examples thereof include inorganic fillers. In addition, by subjecting the protective film to laser marking (a method of printing the surface of the protective film by using laser light), the portion (factor) cut off by the laser light exposes the filler (C) to diffuse the reflected light Therefore, the contrast with the non-factor part is improved, and recognition becomes possible.

Preferable inorganic fillers include powders such as silica, alumina, talc, calcium carbonate, titanium oxide, iron oxide, silicon carbide, and boron nitride, beads spheroidizing them, single crystal fibers, and glass fibers. Of these, silica fillers and alumina fillers are particularly preferred. In addition, the said inorganic filler can be used individually or in mixture of 2 or more types.

The average particle diameter of the filler is not particularly limited, but is preferably 0.1 to 20 μm. When it is 0.1 micrometer or more, when the composition for forming a protective film is applied and dried on a support sheet to obtain a film for forming a protective film, the composition for forming a protective film tends to be a property suitable for application. Moreover, if it is 20 micrometers or less, a gross value will become easy to improve more.

Moreover, from these viewpoints, the average particle diameter of the filler is more preferably 0.2 to 10 μm, and even more preferably 0.3 to 6 μm.

In addition, the average particle diameter was measured by the particle size distribution system using the dynamic light scattering method. Examples of the particle size distribution system include Nanotrac 150 manufactured by Nikkiso Co., Ltd., and the like.

The content of the filler (C) in the film for forming a protective film is a proportion of the total mass (in terms of solid content) of the film for forming a protective film, preferably 10% by mass or more, more preferably 30% by mass or more, and 50% by mass % Is more preferable. The content of the filler (C) is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 63% by mass or less, based on the total mass of the film for forming a protective film. (C) By making content of a filler into these ranges, it becomes easy to exhibit the effect of the said filler. In addition, by setting the content of the filler (C) to 50% by mass or more, the contrast between the laser-marked printing portion and the non-printing portion is improved, and the recognition performance of the printing is improved. Moreover, it becomes easy to improve a gross value by setting it below the said upper limit.

The film for forming a protective film according to the present invention includes any of the following (D) coloring agents, (E) coupling agents, (F) curing accelerators, and (G) other additives, in addition to the components (A) to (C) described above. It may contain more than one dog.

<(D) Coloring agent>

The film for forming a protective film preferably contains (D) a colorant because the semiconductor chip can be prevented from malfunctioning of the semiconductor chip by shielding infrared rays or the like generated from surrounding devices when the semiconductor chip is embedded in the device. In addition, by containing the colorant (D), character identification when printing a product number, mark, or the like on the protective film obtained by curing the protective film-forming film can be improved. That is, the product number or the like is usually printed on the back surface of the semiconductor chip formed with the protective film, but the protective film contains the colorant (D), thereby increasing the contrast difference between the printed part and the non-factor part, thereby improving identification. .

(D) As a colorant, an organic or inorganic pigment or dye is used. As the dye, any dye such as an acid dye, a reaction dye, a direct dye, a disperse dye, and a cationic dye can be used. Further, the pigment is not particularly limited, and may be appropriately selected from known pigments and used.

Among these, a black pigment that is capable of further improving the discrimination by a laser marking method while having good shielding properties of electromagnetic waves and infrared rays is more preferable. Carbon black, iron oxide, manganese dioxide, aniline black, activated carbon, and the like are used as the black pigment, but are not limited to these. Carbon black is particularly preferable from the viewpoint of increasing the reliability of the semiconductor chip. (D) The colorant may be used alone or in combination of two or more.

(D) The blending amount of the colorant is a proportion of the total mass (in terms of solid content) of the film for forming a protective film, preferably 0.01 to 25% by mass, more preferably 0.03 to 15% by mass.

<(E) Coupling agent>

(E) A coupling agent may be mix | blended with the film for protective film formation.

(E) As the coupling agent, a silane coupling agent having an alkoxy group such as a methoxy group or an ethoxy group is preferable. Moreover, as (E) coupling agent, the compound which has reactive functional groups other than an alkoxy group which reacts with the functional group which (A) acrylic polymer or (B) epoxy curable component etc. has is used preferably. Examples of the reactive functional group include glycidoxy groups, epoxy groups other than glycidoxy groups, amino groups, (meth) acryloxy groups, vinyl groups other than (meth) acryloxy groups, mercapto groups, and the like. Among these, a glycidoxy group and an epoxy group are preferable.

As the silane coupling agent, a low molecular weight silane coupling agent having a molecular weight of less than 300 may be used, or an oligomeric type silane coupling agent having a molecular weight of 300 or more may be used, or they may be used in combination.

As a low molecular weight silane coupling agent, specifically, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4- Epoxycyclohexyl) ethyltrimethoxysilane, γ- (methacrylopropyl) trimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, N-6- And (aminoethyl) -γ-aminopropylmethyldiethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, and vinyl triacetoxysilane.

It is preferable that the oligomeric type silane coupling agent is an organopolysiloxane having a siloxane skeleton and has an alkoxy group directly bonded to a silicon atom.

(E) The content of the coupling agent is a proportion of the total mass (in terms of solid content) of the film for forming a protective film, preferably 0.01 to 10.0 mass%, more preferably 0.1 to 3.0 mass%.

<(F) Curing accelerator>

(F) The curing accelerator may be contained in the film for forming a protective film in order to adjust the curing rate of the protective film forming layer.

Preferred curing accelerators include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris (dimethylaminomethyl) phenol; 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5 -Imidazoles such as hydroxymethyl imidazole; Organic phosphine such as tributylphosphine, diphenylphosphine, and triphenylphosphine; And tetraphenyl boron salts such as tetraphenyl phosphonium tetraphenyl borate and triphenylphosphine tetraphenyl borate. These can be used individually by 1 type or in mixture of 2 or more types.

The curing accelerator (F) is contained in an amount of preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the epoxy curable component (B). (F) By containing the curing accelerator in an amount in the above range, the film for forming a protective film has excellent adhesion properties even when exposed to high temperature and high humidity, and high reliability can be achieved even when exposed to strict conditions.

<(G) Other additives>

Other additives that may be included in the film for forming a protective film are not particularly limited, but crosslinking agents, compatibilizers, leveling agents, plasticizers, antistatic agents, antioxidants, ion trapping agents, gettering agents, chain transfer agents, energy rays Polymerizable compounds, photopolymerization initiators, and the like. For the film for forming a protective film, for example, by mixing a compatibilizer, the compatibility between the phases with many (A) components and the phases with many cured products of (B) components is appropriately adjusted, and an appropriate phase separation structure can be designed.

<Gross value>

The film for protective film formation has a gloss value of 20 or more as measured by JIS Z 8741 on at least one surface of the protective film obtained by curing by having the above-mentioned compounding. In the present invention, the surface on the opposite side to the surface having the gross value of 20 or more is attached to the wafer and cured, so that the surface of the target by laser marking of the protective film has a gross value of 20 or more. Therefore, in the present invention, the contrast of the printing portion and the non-printing portion is improved, and the discrimination of the printing portion is improved.

It is preferable that the gross value is 27 or more, because the contrast is further improved to increase the discrimination of characters. Moreover, although a gross value is not specifically limited, It is preferable that it is 45 or less.

In addition, although the gross value is not specifically limited, For example, adjustment of the amount of the epoxy group containing monomer or the alkyl group (meth) acrylic acid alkyl ester having 4 or more carbon atoms, the content of the component (B) to the component (A) It can be appropriately adjusted according to adjustment, selection of the type of filler, adjustment of the content or particle size of the filler, or addition of other additives.

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

[Composite sheet for forming a protective film]

The film for forming a protective film of the present invention is usually formed to be peelable on a support sheet, and is used as a composite sheet for forming a protective film as a laminate. The film for forming a protective film can be made into the same shape as a support sheet. In addition, the composite sheet for forming a protective film is produced in a shape in which the film for forming a protective film can have a shape substantially the same as a wafer or a shape of a wafer, and is laminated on a support sheet having a size larger than the film for forming a protective film. In other words, it may be taking a so-called pre-molding configuration.

The support sheet supports a film for forming a protective film, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate Film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate copolymer film, ionomer resin film, ethylene · (meth) acrylic acid copolymer film, ethylene · (meth) acrylic acid ester copolymer film , Polystyrene films, polycarbonate films, polyimide films, films such as fluororesin films are used. In addition, these crosslinked films are also used. Moreover, it may be two or more laminated films selected from these. Moreover, the film which colored these can also be used.

The surface on the side of the support sheet on which the film for forming a protective film is formed may be appropriately subjected to a peeling treatment. Examples of the peeling agent used in the peeling treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based adhesives, but the alkyd-based, silicone-based, and fluorine-based peeling agents are preferred because they have heat resistance.

In addition, in the composite sheet for forming a protective film, a light peeling release sheet is bonded to a surface opposite to the surface on the side where the support sheet of the film for forming a protective film is formed, and the film for forming a protective film is protected by the release sheet. It may be.

The film for forming a protective film is obtained by applying and drying the composition for forming a protective film formed by mixing the above components in an appropriate ratio in a suitable solvent or without a solvent. In addition, a protective film forming composition may be applied onto a process film different from the support sheet, dried and formed into a film, and appropriately transferred to a support sheet or the like to form the film. The process film can also be used as the above-mentioned release sheet without being removed thereafter.

In addition, the surface tension of the support sheet can also be adjusted by laminating the film by wet lamination, dry lamination, hot melt lamination, melt extrusion lamination, coextrusion, or the like. That is, the film in which the surface tension of at least one surface is within a preferred range as that of the surface contacting the film for forming a protective film of the support sheet described above is laminated with another film so that the surface becomes a surface contacting the film for forming a protective film. A laminate can also be produced and used as a support sheet.

Moreover, the adhesive sheet which formed the adhesive layer on the said film can also be used as a support sheet. In this case, the film for forming a protective film is laminated on the pressure-sensitive adhesive layer formed on the support sheet. By setting it as such a structure, it is preferable because the fixing performance of a wafer or a chip becomes excellent especially when a wafer is divided into chips for every film or protective film for forming a protective film on a composite sheet for forming a protective film. It is preferable to use the pressure-sensitive adhesive layer as a releasable pressure-sensitive adhesive layer because it is easy to separate the protective film forming film or protective film from the support sheet. As the releasable pressure-sensitive adhesive layer, a weakly adhesive substance having an adhesive strength sufficient to release the protective film-forming film may be used, or an energy ray-curable substance having reduced adhesive strength by energy ray irradiation may be used. Specifically, the releasable pressure-sensitive adhesive layer is a variety of pressure-sensitive adhesives conventionally known (for example, rubber-based, acrylic-based, silicone-based, urethane-based, vinyl ether-based general-purpose adhesives, adhesives with surface irregularities, energy ray curable adhesives, thermal expansion) Component-containing adhesives, and the like).

In the case of using the energy ray-curable releasable pressure-sensitive adhesive layer, when the composite sheet for forming a protective film has a preformed configuration, energy ray irradiation is performed in advance on the region where the film for forming a protective film is laminated to reduce the adhesiveness. On the other hand, other regions may not be irradiated with energy rays, and for example, for the purpose of adhesion to a jig, the adhesive force may be kept high. In order not to perform energy ray irradiation only in other regions, an energy ray shielding layer may be formed, for example, by printing or the like in a region corresponding to other regions of the support sheet, and energy ray irradiation may be performed from the support sheet side. In addition, in order to obtain the same effect, a structure in which a film for forming a protective film and a removable pressure-sensitive adhesive layer having a substantially the same shape as the film for forming a protective film are further laminated on a region where the film for forming a protective film on the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet is laminated may be used. have. As the film for the removable pressure-sensitive adhesive, the same ones as described above can be used.

When the film for forming a protective film does not take a pre-formed configuration, a separate adhesive layer or double-sided adhesive tape is provided on the outer circumference of the surface of the film for forming a protective film (the surface in contact with the adherend) to fix other jigs such as ring frames. It may be formed. When the film for forming a protective film takes a pre-formed configuration, a separate adhesive layer or double-sided adhesive tape is used to fix another jig such as a ring frame in an area where the film for forming a protective film in the outer circumference of the support sheet is not laminated. May be formed.

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

The film for forming a protective film is adhered to an adherend such as a semiconductor wafer or a semiconductor chip, and then thermally cured to be used as a protective film. Here, when the film for forming a protective film is adhered to an adherend as a composite sheet for forming a protective film, first, when it is protected by a release sheet, the release sheet is peeled off, and then, the film for protection film formation and the supporting film are laminated. After the body is attached to the adherend, the support sheet is peeled from the film for forming a protective film.

Hereinafter, the method of using the film for forming a protective film will be described as an example in which the film for forming a protective film is used for protecting the back surface of a semiconductor chip, and a chip with a protective film is produced, but is not limited to the examples shown below.

In this method, first, the film for forming a protective film is laminated on the back surface of a 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 base sheet is attached to the back surface of the semiconductor wafer. Then, after peeling the support sheet from the film for forming a protective film, the film for forming a protective film laminated on a semiconductor wafer is thermally cured to form a protective film on the entire surface of the wafer.

Further, the semiconductor wafer may be a silicon wafer or a compound semiconductor wafer such as gallium arsenide. In addition, the semiconductor wafer has a circuit formed on its surface, the back surface is appropriately ground, and the like, and has a thickness of about 50 to 500 µm.

Subsequently, the laminate of the semiconductor wafer and the protective film is diced for each circuit formed on the wafer surface. Dicing is performed so as to cut both the wafer and the protective film, and the dicing of the semiconductor wafer and the protective film is divided into a plurality of chips by dicing. In addition, dicing of a wafer is performed by the usual method using a dicing sheet. Subsequently, the diced chip is picked up by a general-purpose means such as collet to obtain a semiconductor chip (a chip with a protective film) having a protective film on the back surface.

In addition, the manufacturing method of a semiconductor chip is not limited to the above example, For example, peeling of a support sheet may be performed after thermosetting of a protective film, or after dicing. Moreover, when peeling of a support sheet is performed after dicing, the support sheet can serve as a dicing sheet. Moreover, the thermosetting of the film for protective film formation can also be performed after dicing.

[Chip with protective film]

The chip provided with the protective film of the present invention is obtained, for example, by the above manufacturing method, and includes a semiconductor chip and a protective film laminated on the back surface of the semiconductor chip, and the protective film cures the film for forming the protective film described above. It is formed to protect the back side of the chip. In the protective film, the surface opposite to the surface on the semiconductor chip side has a gross value of 20 or more as measured by JIS Z 8741.

A semiconductor device can be manufactured by mounting a chip with a protective film on a substrate or the like in a face-down method. In addition, the semiconductor device can also be manufactured by adhering a chip with a protective film onto another member (on a chip mounting portion) such as a die pad portion or a separate semiconductor chip.

<Example>

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

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

(1) Weight average molecular weight (Mw)

The weight average molecular weight Mw of standard polystyrene conversion was measured by the gel permeation chromatography (GPC) method.

Measuring device: Tosoh's high-speed GPC device `` HLC-8120GPC '', the high-speed column `` TSK guard column (guard column) H _XL- H '', `` TSK gel (Gel) GMH <sub>XL</sub> '', `` TSK gel G2000 H _XL '' ( As described above, all manufactured by Tosoh Corporation) were connected and measured in this order.

Column temperature: 40 ° C, feeding rate: 1.0 mL / min, detector: differential refractive index meter

(2) Gross value

A film for forming a protective film of a composite sheet for forming a protective film obtained by peeling a release sheet on a polished surface of a # 2000 polished silicon wafer (200 mm diameter, 280 μm thick), a tape mounter (Adwill, manufactured by Lintec Co., Ltd.) ) RAD-3600 F / 12) was used while heating to 70 ° C. Subsequently, after peeling a support sheet, the film for protective film formation was hardened by heating at 130 degreeC for 2 hours, and the protective film was formed on the silicon wafer. Under the following measurement apparatus and measurement conditions, the mirror surface glossiness of 60 degrees of the protective film surface was measured, and it was set as the gross value.

Measuring device: VG 2000 Nippon Denshoku High School, Ltd.

Measurement conditions: according to JIS Z 8741

(3) Recognition of characters (humanity)

A film for forming a protective film of a composite sheet for forming a protective film obtained by peeling a release sheet on a polished surface of a # 2000 polished silicon wafer (200 mm diameter, 280 μm thick), a tape mounter (made by Lintec Co., Ltd., Adwill RAD- 3600 F / 12) while heating to 70 ° C. Subsequently, after peeling a support sheet, the film for protective film formation was hardened by heating at 130 degreeC for 2 hours, and the protective film was formed on the silicon wafer. A laser printing apparatus (LP-V10U manufactured by Panasonic Device SUNX, laser wavelength: 1056 nm) was used on the surface of the protective film to print four characters of characters having a width of 300 µm or less. The obtained printed protective film surface was checked with a digital microscope to confirm whether the printing was readable. As for the judgment criteria, when observing the digital microscope, when the printing part was illuminated with direct sunlight, "A" was readable enough, "B" was readable but not clear, and "F" was not readable.

(4) Reliability evaluation

A film for forming a protective film of a composite sheet for forming a protective film obtained by peeling a release sheet on a polished surface of a # 2000 polished silicon wafer (200 mm diameter, 280 μm thick), a tape mounter (made by Lintec Co., Ltd., Adwill RAD- 3600 F / 12), while heating to 70 ° C. Subsequently, after peeling a support sheet, the film for protective film formation was hardened by heating at 130 degreeC for 2 hours, and the protective film was formed on the silicon wafer. Reliability by attaching the protective film side to a dicing tape (AdWill D-676H manufactured by Lintec Co., Ltd.) and dicing to a size of 3 mm x 3 mm using a dicing device (manufactured by Disco Co., Ltd., DFD651) A chip with a protective film for evaluation was obtained.

The chip provided with the protective film for reliability evaluation was first processed under conditions (preconditions) that mimic the process in which the semiconductor chip is actually mounted. Specifically, the chip with the protective film was baked at 125 ° C for 20 hours, and then left to stand for 168 hours under the conditions of 85 ° C and 85% RH to absorb moisture, and then immediately preheat 160 ° C, peak temperature 260 ° C, and heating It was passed through the IR reflow furnace three times under the condition of time 30 seconds. Twenty-five chips with protective films treated with these pre-conditions were installed in a cold heat shock device (ESPEC manufactured by TSE-11-A), held at -65 ° C for 10 minutes, and thereafter. The cycle of holding at 150 ° C for 10 minutes was repeated 1000 times.

Thereafter, chips with 25 protective films were taken out from the cold heat shock device to evaluate reliability. Specifically, the presence or absence of excitation / exfoliation at the junction between the chip and the protective film or the presence or absence of cracks in the protective film is observed by a scanning ultrasonic inspection device (Hye-Focus manufactured by Hitachi Genki Fine Tech Co., Ltd.) and cross-section. Evaluated by, it was referred to as NG if any of the lifting, peeling and cracking. Table 4 shows the number of NGs among the 25 chips.

Example 1

In Example 1, the components forming the protective film-forming film were as follows.

(A) Acrylic copolymer: weight average obtained by copolymerizing 1 part by mass of n-butyl acrylate, 79 parts by mass of methyl methacrylate, 15 parts by mass of 2-hydroxyethyl acrylate, and 5 parts by mass of glycidyl methacrylate Copolymer with molecular weight (Mw) of 370,000 and glass transition temperature (Tg) of 7 ° C

(B) Epoxy-based curable component

Epoxy-based compounds: bisphenol A-type epoxy resin (manufactured by Nippon Shokubai Co., Ltd., BPA-328) and dicyclopentadiene-type epoxy resin (manufactured by Dai Nippon Ink Chemical Co., Ltd., Epiclon HP-7200HH)

Heat curing agent: Dicyandiamide (made by ADEKA, Adeka Hardner 3636AS)

(C) Filler: Fused quartz filler with an average particle diameter of 8 µm (silica filler, manufactured by Tatsumori, physically crushed SV-10)

(D) Coloring agent: Carbon black (Mitsubishi Chemical Co., Ltd., MA600, average particle diameter: 28 nm)

(E) Silane coupling agent: Oligomer type silane coupling agent (X-41-1056 methoxy equivalent of 17.1 mmol / g, molecular weight 500 to 1500, manufactured by Shin-Etsu Chemical Co., Ltd.) and γ-glycidoxypropyl tree Ethoxysilane (KBE-403 methoxy equivalent, 8.1 mmol / g, molecular weight 278.4 by Shin-Etsu Chemical Co., Ltd.) and γ-glycidoxypropyl trimethoxysilane (Shin-Etsu Chemical Co., Ltd. KBM-403 methoxy equivalent 12.7mmol / g, molecular weight 236.3)

(F) Curing accelerator: 2-phenyl-4,5-dihydroxymethylimidazole (Shikoku Chemical Co., Ltd., Cursol 2PHZ)

A polyethylene terephthalate film (SP-PET5011 manufactured by Lintec Co., Ltd., 50 µm thick) obtained by diluting the composition for forming a protective film blended with each of the materials in the ratio shown in Table 1 with methyl ethyl ketone and peeling treatment on one side. On the peeling treatment surface of the support sheet containing, the thickness after drying and removal was applied to be 25 µm, and dried at 100 ° C for 3 minutes to form a film for forming a protective film on the support sheet. Subsequently, another release sheet (made by Lintec Co., Ltd., SP-PET3811, thickness 38 µm) was superimposed on the film for forming a protective film to obtain a composite sheet for forming a protective film of Example 1.

 Example 2, Comparative Examples 1-6

(A) It carried out similarly to Example 1 except having used what was shown in Table 2 as an acrylic copolymer. Table 2 also shows the weight average molecular weight (Mw) and glass transition temperature (Tg) for the acrylic copolymer (A) of each of Examples and Comparative Examples.

Example 3

(C) It carried out similarly to Example 2 except having used the silica filler (made by Tokuyama Corporation, UF310) of an average particle diameter of 3 micrometers instead of the silica filler of average particle diameter 8 micrometers as a component.

Example 4

As a component (C), it carried out similarly to Example 2 except having used the silica filler (SC2050MA by Admatex Corporation) with an average particle diameter of 0.5 micrometer instead of the silica filler of average particle diameter of 8 micrometers.

Examples 5 and 6

(C) It carried out similarly to Example 2 except having changed the compounding quantity of a component as shown in Table 3.

Examples 7, 8

It carried out similarly to Example 2 except having changed the compounding quantity of (A) and (B) component as shown in Table 3.

For each of Examples 1 to 8 and Comparative Examples 1 to 6, the gross value was measured, and the factor recognition and reliability were evaluated. Table 4 shows the results.

As is apparent from Table 4, in Examples 1 to 8, (A) the acrylic polymer contained 8 mass% or less of an epoxy group-containing monomer as a constituent monomer, and the glass transition temperature was -3 ° C or higher, (A ) As the phase separation property of the phase with many components and the phase with many cured products of component (B) became good, and the gross value could also be set to 20 or more, both the factor recognition and reliability could be improved.

On the other hand, in Comparative Example 1, since the acrylic polymer (A) did not contain an epoxy group-containing monomer as a constituent monomer, minute unevenness occurred on the surface of the protective film due to phase separation, and as a result, scattering of reflected light on the surface of the protective film Effect. Therefore, the gross value became small, and the printability was deteriorated. In Comparative Examples 2, 3, and 6, the glass transition temperature of the acrylic polymer (A) was less than -3 ° C, so it was estimated that the protective film was deformed by thermal history, and the number of NG chips increased, and the protective film was provided. The reliability of one chip could not be sufficiently improved. In addition, in Comparative Examples 4 and 5, since the (A) acrylic polymer contained a large amount of the epoxy group-containing monomer as a constituent monomer, the affinity between the (A) component and the (B) component was high, and phase separation was unlikely to occur, resulting in a protective film. The reliability of the chip equipped with was lowered.

Claims (8)

A film for forming a protective film for forming a protective film for protecting a semiconductor chip,
The film for forming a protective film contains (A) an acrylic polymer, (B) an epoxy-based curable component, and (C) a filler,
(A) while the monomer constituting the acrylic polymer contains an epoxy group-containing monomer in a proportion of 8% by mass or less of the total monomers, and (A) the glass transition temperature of the acrylic polymer is -3 ° C or higher,
(A) While the monomer constituting the acrylic polymer further contains an (meth) acrylic acid alkyl ester, and among the (meth) acrylic acid alkyl esters, the (meth) acrylic acid alkyl ester having 4 or more carbon atoms in the alkyl group is (A) an acrylic polymer. And 12% by mass or less of all monomers constituting
A film for forming a protective film having a gross value of 20 or more as measured by JIS Z 8741 on at least one surface of the protective film obtained by curing the film for forming a protective film. The film for forming a protective film according to claim 1, wherein the glass transition temperature of the acrylic polymer (A) is 6 ° C. or less. The film for forming a protective film according to claim 1 or 2, wherein the alkyl group has a (meth) acrylic acid alkyl ester having 4 or more carbon atoms (butyl) (meth) acrylate. The film for forming a protective film according to claim 1 or 2, wherein the content of the filler (C) is 50% by mass or more of the film for forming a protective film. The film for forming a protective film according to claim 1 or 2, further comprising a colorant (D). A semiconductor chip and a chip having a protective film, the protective film being formed on the semiconductor chip,
While the protective film is formed by curing the film for forming a protective film, the film for forming a protective film contains (A) an acrylic polymer, (B) an epoxy-based curable component, and (C) a filler,
(A) while the monomer constituting the acrylic polymer contains an epoxy group-containing monomer in a proportion of 8% by mass or less of the total monomers, and (A) the glass transition temperature of the acrylic polymer is -3 ° C or higher,
(A) While the monomer constituting the acrylic polymer further contains an (meth) acrylic acid alkyl ester, and among the (meth) acrylic acid alkyl esters, the (meth) acrylic acid alkyl ester having 4 or more carbon atoms in the alkyl group is (A) an acrylic polymer. And 12% by mass or less of all monomers constituting
The protective film is a chip provided with a protective film having a gross value of 20 or more on a surface opposite to the surface on the semiconductor chip side measured by JIS Z 8741. delete delete