TW201428078A - Protective film forming film - Google Patents

Abstract

The film for forming a protective film of the present invention is a film for forming a protective film for protecting a protective film for a semiconductor wafer, and the film for forming a protective film contains (A) an acrylic polymer and (B) an epoxy-based curable component. (C) a filler, and (D1) a decane coupling agent, wherein the monomer of the (A) acrylic polymer does not contain an epoxy group-containing monomer, or contains 8% by mass or less of all monomers. The monomer of the epoxy group has a glass transition temperature of (A) the acrylic polymer of -3 ° C or more, and the molecular weight of the (D1) decane coupling agent is 300 or more.

Description

Protective film forming film

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

Heretofore, there has been a fabrication of a semiconductor device using a mounting method called a face down method. In the flip-chip method, the semiconductor wafer is bonded to the surface of the wafer through which the electrode or the like is formed, and the substrate is bonded to the substrate, and the back surface of the wafer is exposed, and is protected by a protective film. Further, the back surface of the semiconductor wafer protected by the protective film (hereinafter referred to as "wafer with protective film") is printed on the protective film by laser printing or the like.

The protective film is formed by, for example, resin coating. In recent years, for example, as disclosed in Patent Document 1, in order to ensure uniformity of film thickness and the like, a film formed by adhering a protective film is being put into practical use. In the film for forming a protective film, the film for forming a protective film is provided on a support sheet, and the film for forming a protective film contains a thermosetting component containing an epoxy resin or the like, and an adhesive containing an acrylic polymer or the like. Polymer composition.

On the other hand, a variety of adhesive films used in semiconductors are known. For example, as disclosed in Patent Document 2, resin A having an elastic modulus of 3,500 to 10,000 GPa and a bomb are separated from each other in a B-stage state. A mixture of the resin B having a modulus of 1 to 3000 MPa is used as an essential component, and is used as a film for use in a semiconductor package or the like. In the adhesive film of Patent Document 2, for example, an epoxy resin as the resin A and an acrylic rubber using a copolymer of methacrylate and acrylonitrile as the resin B are used.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2002-280329

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2001-220556

When the protective film for forming a semiconductor wafer is formed by the protective film forming sheet disclosed in Patent Document 1, the wafer with the protective film is liable to cause floating and peeling at the joint portion between the wafer and the protective film due to long-term use. The crack is generated on the protective film, and the reliability is deteriorated. Further, as disclosed in Patent Document 2, when the composition in which the two components are phase-separated is transferred to the sheet for forming a protective film, the reliability may be improved, but there is a case where sufficient reliability cannot be obtained. .

The present invention has been made in view of the above problems, and it has been a problem to obtain a wafer with a protective film which is sufficiently improved in reliability.

In order to solve the above problems, the inventors of the present invention have repeatedly studied the results, and found that the acrylic copolymer is set to a predetermined combination, and the glass transition temperature of the acrylic polymer is set to a predetermined range. In the meantime, a decane coupling agent having a molecular weight of a predetermined value or more is used in combination to improve the reliability of the film for forming a protective film, and the following invention is completed.

That is, the present invention provides the following (1) to (7).

(1) A film for forming a protective film for forming a film for forming a protective film for protecting a protective film of a semiconductor wafer, wherein the film for forming a protective film contains (A) an acrylic polymer and (B) an epoxy-based hardening film. a component, (C) filler, and (D1) a decane coupling agent; the monomer constituting the (A) acrylic polymer does not contain an epoxy group-containing monomer, or accounts for 8 mass% or less of all monomers. The epoxy group-containing monomer is contained, and the glass transition temperature of the (A) acrylic polymer is -3 ° C or higher; and the molecular weight of the (D1) decane coupling agent is 300 or more.

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

(3) The film for forming a protective film according to the above (2), wherein the single system comprising the (A) acrylic polymer has an alkyl group having a carbon number of 4 or more in an amount of 12% by mass or less based on the total of the monomers. The alkyl (meth)acrylate.

(4) The film for forming a protective film according to the above (3), wherein the alkyl group has a carbon number of 4 or more (meth)acrylic acid alkyl ester (butyl) methacrylate.

(5) The film for forming a protective film according to any one of the above (1), further comprising (E) a coloring agent.

(6) The thin film for forming a protective film according to any one of the above (1) to (5) A film wherein the (D1) decane coupling agent is a compound having an alkoxy equivalent weight of more than 13 mmol/g.

(7) A wafer with a protective film, which is a wafer with a protective film attached to a semiconductor wafer and a protective film provided on the semiconductor wafer; The protective film is formed by curing a film for forming a protective film, and the film for forming a protective film contains (A) an acrylic polymer, (B) an epoxy-based curable component, (C) a filler, and (D1). Decane coupling agent; The monomer constituting the (A) acrylic polymer does not contain an epoxy group-containing monomer, or contains an epoxy group-containing monomer in a proportion of 8% by mass or less of all monomers, and (A) acrylic polymerization The glass transition temperature of the object is above -3 ° C; (D1) The molecular weight of the decane coupling agent is 300 or more.

By using the film for forming a protective film of the present invention, a wafer with a protective film having excellent reliability can be obtained.

[Formation of the Invention]

Hereinafter, the present invention will be specifically described using its embodiment.

In the present specification, "(meth)acrylic acid" is used as a term indicating both "acrylic acid" and "methacrylic acid", and other similar terms are also the same.

[film for forming a protective film]

The film for forming a protective film of the present invention is a film for forming a protective film for protecting a semiconductor wafer, and comprises at least (A) an acrylic polymer, (B) an epoxy-based curable component, and (C) a filler. And (D1) decane coupling agent.

<(A) Acrylic Polymer>

(A) The acrylic polymer is a component which imparts flexibility and film formability to a film for forming a protective film and a protective film, wherein a single system constituting the acrylic polymer does not contain an epoxy group-containing monomer, or constitutes The proportion of 8% by mass or less of all monomers of the acrylic polymer contains a monomer containing an epoxy group.

In the case where the monomer constituting the acrylic polymer contains an epoxy group-containing monomer, the monomer constituting the (A) acrylic polymer, specifically, it comprises: an epoxy group-containing (methyl group) One or more epoxy group-containing monomers of an acrylate and a non-acrylic epoxy group-containing monomer, and various (meth) acrylates and/or non-acrylic groups having no epoxy group A monomer that does not contain an epoxy group. In such a case, when the epoxy group-containing monomer contains only the non-acrylic epoxy group-containing monomer, the single system constituting the acrylic polymer contains various (meth)acrylic groups having no epoxy group. ester.

When the proportion of the epoxy group-containing monomer is more than 8% by mass, the compatibility between the (A) component and the cured product of the component (B) is improved, and the phase separation structure described later becomes difficult to form, and the wafer with the protective film is reliable. Reduced sex. From such a viewpoint, the content of the epoxy group-containing monomer is preferably 6% by mass or less based on the total monomers of the (A) acrylic copolymer.

Examples of the epoxy group-containing (meth) acrylate include (meth) Glycidyl acrylate, β-methyl glycidyl (meth)acrylate, (3,4-epoxycyclohexyl)methyl (meth)acrylate, 3-epoxy ring 2 (meth)acrylate Examples of the non-acrylic epoxy group-containing monomer include a hydroxypropyl ester and the like, and examples thereof include glycidyl butenoate and allyl glycidyl ether. The epoxy group-containing monomer is preferably an epoxy group-containing (meth) acrylate.

Further, by including the epoxy group-containing monomer, the monomer constituting the acrylic polymer (A) can easily suppress the decrease in the gloss value of the protective film caused by the phase separation, and it is easy to improve. The visibility of the printed portion printed by laser. Therefore, in applications requiring good print recognition, it is preferred to contain an epoxy group-containing monomer.

In the case of containing an epoxy group-containing monomer, the content of the epoxy group-containing monomer is generally 0.1% by mass or more based on the total monomers, and from the viewpoint of improving print recognition, it is preferred to account for all the monomers. The mass is 1% by mass or more, and more preferably 3% by mass or more.

When the monomer constituting the acrylic polymer does not contain an epoxy group-containing monomer, specifically, the monomer constituting the (A) acrylic polymer contains a hydroxyl group (meth) acrylate, (methyl group) Any of various (meth) acrylates such as alkyl acrylates which do not have various epoxy groups, and non-acrylic compounds which do not contain an epoxy group, such as styrene, ethylene, vinyl ether, vinyl acetate, etc. which are used together as needed. Monomer.

Further, as the monomer constituting the (A) acrylic polymer, it is preferred to contain an alkyl (meth)acrylate. Accordingly, it is easy to adjust (A) the glass transition of the acrylic polymer by the combination of the increase or decrease in the carbon number of the alkyl (meth)acrylate and the alkyl (meth)acrylate having different carbon numbers. Move the temperature. The alkyl (meth)acrylate is preferably 50% by mass or more, and more preferably 70% by mass or more, based on all monomers of the (A) acrylic polymer. Further, the alkyl (meth)acrylate is preferably 92% by mass or less of all the monomers constituting the (A) acrylic polymer.

Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and amyl (meth)acrylate. , 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, ( Methyl methacrylate, dodecyl (meth)acrylate, etc., alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms.

In addition, the monomer constituting the (A) acrylic polymer preferably contains the above (meth)acrylic acid alkyl ester in an amount of 12% by mass or less based on the total of the monomers constituting the (A) acrylic polymer. The alkyl (meth)acrylate having an alkyl group having 4 or more carbon atoms. Accordingly, it is easy to optimize the gloss value while adjusting the glass transition temperature to -3 ° C or higher. In order to maintain the reliability and increase the gloss value, the content of the alkyl (meth) acrylate having an alkyl group of 4 or more is preferably from 1 to 12% by mass, more preferably from 5 to 12% by mass. The (meth)acrylic acid alkyl ester having 4 or more carbon atoms in the alkyl group is preferably butyl (meth)acrylate.

Further, the monomer constituting the (A) acrylic polymer is preferably an alkyl (meth)acrylate containing an alkyl group in the alkyl (meth)acrylate having a carbon number of 3 or less. By improving the thermal stability and the like by the alkyl (meth)acrylate having an alkyl group having 3 or less carbon atoms, it is also easy to adjust the glass transition temperature of the (A) acrylic polymer to It is -3 ° C or more as described later. From such a viewpoint, the alkyl (meth)acrylate having an alkyl group having 3 or less carbon atoms is preferably 50% by mass or more, more preferably 60% by mass of all the monomers constituting the (A) acrylic polymer. %the above. Further, the alkyl (meth)acrylate having an alkyl group having 3 or less carbon atoms is preferably 90% by mass or less of all the monomers constituting the (A) acrylic polymer. Further, the alkyl (meth)acrylate having 3 or less carbon atoms of the alkyl group is preferably methyl (meth)acrylate or ethyl (meth)acrylate, more preferably (meth)acrylic acid. ester.

Further, the monomer constituting the (A) acrylic polymer preferably contains a hydroxyl group (meth) acrylate. When the hydroxyl group is introduced into the acrylic copolymer by containing a hydroxyl group (meth) acrylate, it is easy to control the adhesion and adhesion characteristics of the semiconductor wafer. Examples of the hydroxyl group-containing (meth) acrylate include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate.

The hydroxyl group-containing (meth) acrylate is preferably from 1 to 30% by mass, more preferably from 5 to 25% by mass, even more preferably from 10 to 20% by mass, based on the total of the monomers constituting the (A) acrylic polymer.

Further, the monomer constituting the (A) acrylic polymer may contain a non-acrylic epoxy group-free monomer such as styrene, ethylene, vinyl ether or vinyl acetate as described above.

The weight average molecular weight (Mw) of the (A) acrylic polymer is preferably 10,000 or more in order to impart flexibility and film formability to the film for forming a protective film. Further, the weight average molecular weight is more preferably from 15,000 to 1,000,000, still more preferably from 20,000 to 500,000. The weight average molecular weight (Mw) can be measured according to the method of the examples described later.

In the (A) acrylic polymer of the present invention, the glass transition temperature is -3 ° C or higher. When the glass transition temperature is less than -3 ° C, the fluidity of the (A) acrylic polymer cannot be sufficiently suppressed, and the protective film is easily deformed by heat stagnation, and the reliability of the wafer with the protective film cannot be sufficiently improved. . In the present invention, the glass transition temperature of the (A) acrylic polymer is a theoretical value determined according to the formula of Fox.

Further, the glass transition temperature of the (A) acrylic polymer is preferably 6 ° C or lower. By setting the glass transition temperature to 6 ° C or lower, the gloss value described later can be improved, and the visibility of the printed portion can be improved. Although the reason is not necessarily clear, it is presumed that the acrylic polymer (A) has moderate fluidity, and the surface shape of the protective film after curing is smoothed.

The film for forming a protective film is obtained by completely eliminating the component derived from the epoxy group-containing monomer and suppressing the content thereof to a small amount so that the phase of the protective film is rich in the component (A) and is rich in the latter ( B) Phase separation of the hardened component of the component improves the reliability of the wafer with the protective film. It is presumed that the peeling of the protective film due to stress is less likely to occur because the soft (A)-rich phase relaxes the stress due to the deformation of the temperature even if the temperature changes after the wafer is assembled. . Further, the phase separation in the film for forming a protective film after heat hardening (i.e., the protective film) is preferably such that the phase rich in (A) forms a continuous phase. According to this, the effect of the above reliability improvement can be further improved.

The phase rich in (A) phase and the hardened phase rich in (B) can be determined by, for example, Raman scattering spectrometry, from the measurement chart of a certain phase, by observing what kind of substance can become the main component of the phase. Make a judgment. In addition, the size of the phase separation structure is the case below the decomposition energy of the Raman spectroscopy Next, the hardness measured by the Tapping Mode of the SPM (scanning probe microscope) is used as an index, and it is presumed that the harder one is the phase of the hardened material rich in the (B) component, and the softer one is rich (A) ) the phase of the ingredients. Therefore, in the present invention, it is possible to confirm whether or not a phase separation structure is formed by a protective film obtained by curing a film for forming a protective film by Raman scattering spectrometry or SPM observation.

Further, the ratio of the total mass (calculated as solid content) of the (A) acrylic polymer to the film for forming a protective film is generally 10 to 80% by mass, preferably 15 to 50% by mass.

<(B) epoxy-based curable component>

(B) The epoxy-based curable component is a component for forming a hard protective film formed on a semiconductor wafer, and generally contains an epoxy compound and a thermosetting agent.

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

By setting the content of the (B) epoxy-based curable component in the above range, sufficient adhesion to a member to be bonded such as a semiconductor wafer can be obtained, and the peeling force with a support sheet to be described later can be appropriately obtained. It is possible to prevent peeling failure or the like when the support sheet is peeled off from the film for forming a protective film. Further, by limiting the blending amount of the component (B) as described above to a range below the predetermined upper limit, the phase rich in the component (A) can be easily made continuous. The phase can improve the reliability of the semiconductor wafer and, in addition, it is easy to increase the gloss value.

In addition, the ratio of the total mass (calculated as solid content) of the epoxy-based curable component to the film for forming a protective film is generally from 5 to 60% by mass, preferably from about 10 to 40% by mass.

As the epoxy compound, a previously known epoxy compound can be used. Specific examples thereof include a biphenyl compound, bisphenol A diglycidyl ether and a hydrogenated product thereof, an o-cresol novolac epoxy resin, a dicyclopentadiene type epoxy resin, and a biphenyl type epoxy resin. An epoxy compound having two or more functional groups in a molecule such as a bisphenol A epoxy resin, a bisphenol F epoxy resin, or a phenylene skeleton epoxy resin. These may be used alone or in combination of two or more.

The thermosetting agent functions as a curing agent for an epoxy compound. Preferred examples of the thermosetting agent include compounds having two or more functional groups reactive with an epoxy group in one molecule. Examples of the functional group thereof include 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 include a polyfunctional phenol resin, a biphenol, a novolak type phenol resin, a dicyclopentadiene type phenol resin, a Xylok type phenol resin, and a aryl group. Alkyl phenol resin. Specific examples of the amine-based curing agent having an amine group include dicyandiamide. These may be used alone or in combination of two or more.

Further, it is thermally hardened with respect to 100 parts by mass of the epoxy compound. The content of the agent is preferably from 0.1 to 100 parts by mass, more preferably from 0.5 to 50 parts by mass, still more preferably from 1 to 20 parts by mass. When the content of the thermal curing agent is set to be equal to or higher than the above lower limit value, the component (B) is cured, and the adhesion to the adherend is easily obtained. In addition, by setting the amount to be equal to or lower than the above upper limit, the moisture absorption rate of the film for forming a protective film can be suppressed, and the reliability of the semiconductor device can be easily improved.

<(C) Filler>

(C) The filler is a component which imparts moisture resistance, dimensional stability, and the like to the protective film, and specific examples thereof include an inorganic filler. Further, in the case where a laser mark (a method of removing the surface of the protective film by laser light for printing) is applied to the protective film, the portion (printed portion) which is removed by the laser light is diffused by (C) the filler is exposed. The reflected light is enhanced to be distinguishable from the non-printed portion.

Examples of preferred inorganic fillers include powders such as cerium oxide, aluminum oxide, talc, calcium carbonate, titanium oxide, iron oxide, cerium carbide, and boron nitride, beads which are spheroidized, and single crystal fibers. And glass fiber and so on. Among these, it is particularly preferred to be a cerium oxide filler and an alumina filler. Further, the above inorganic fillers may be used singly or in combination of two or more kinds.

Further, the average particle diameter of the filler is not particularly limited, but is preferably 0.1 to 20 μm. 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 or the like, the composition for forming a protective film tends to have a property suitable for coating. Moreover, when it is 20 micrometer or less, it becomes easy to raise a gloss value further.

In addition, from these viewpoints, the average particle diameter of the filler is preferably 0.2. ~10 μm, further preferably 0.3 to 6 μm.

Further, the average particle diameter can be measured by a particle size distribution meter using Dynamic Light Scattering. Examples of the particle size distribution meter include Nanotrac 150 manufactured by Nikkiso Co., Ltd., and the like.

The content of the (C) filler in the film for forming a protective film is preferably 10% by mass or more, more preferably 30% by mass or more, and more preferably 30% by mass or more, more preferably 30% by mass or more. 50% by mass or more. In addition, the content of the (C) filler is preferably 80% by mass or less, more preferably 70% by mass or less, and still more preferably 63% by mass or less based on the total mass of the film for forming a protective film. By setting the content of the (C) filler in these ranges, it becomes easy to exert the effect of the above filler. Further, by setting the content of the (C) filler to 50% by mass or more, the contrast between the laser-printed portion and the non-printing portion can be improved, and the visibility of printing can be improved. Further, by setting it below the above upper limit value, it becomes easy to increase the gloss value.

<(D1) decane coupling agent>

(D1) A decane coupling agent is an oligomer-type decane coupling agent having a molecular weight of 300 or more, a reactive functional group capable of bonding to the surface of an inorganic material, and a reactive functional group bondable to an organic compound.

The oligomer type (D1) decane coupling agent is susceptible to hydrolysis reaction, and it is easy to bond the surface of the adherend having a physical distance to the polymer component forming the protective film. Therefore, when the (D1) decane coupling agent is heat-cured in the film for forming a protective film, it is likely to chemically react with the surface of the adherend (semiconductor wafer or wafer), and further has an interaction with the dipole on the surface of the adherend. It becomes easy to bond to the surface of the adherend. therefore, The adhesion of the protective film to the semiconductor wafer can be improved, and the reliability of the wafer with the protective film can be improved. In the oligomer-type decane coupling agent, especially an organopolysiloxane having a decane skeleton, and having an alkoxy group directly bonded to a ruthenium atom, which is preferable as an inorganic material surface The reactive functional groups bonded to each other enhance the tendency to enhance the adhesion of the protective film to the semiconductor wafer.

The (D1) decane coupling agent has an alkoxy group as a reactive functional group bondable to the surface of the inorganic material, and the alkoxy equivalent is preferably more than 13 mmol/g. The alkoxy group equivalent is more preferably 15 mmol/g or more. In the present invention, by increasing the alkoxy equivalent, the adhesion to the adherend can be improved, and the reliability of the semiconductor wafer can be easily improved. Further, the alkoxy group equivalent is not particularly limited, and its structure is preferably set to 22 mmol/g or less, more preferably 20 mmol/g or less. Further, the alkoxy group equivalent means the absolute number of alkoxy groups contained in the mass per unit of the compound.

Further, the alkoxy group is preferably an aliphatic hydrocarbon group having 1 to 6 carbon atoms, and specific examples thereof include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, etc., more preferably a methoxy group or a B group. Oxygen.

The molecular weight of the (D1) decane coupling agent is preferably 400 or more, more preferably 500 or more. Further, the molecular weight of the (D1) decane coupling agent is preferably 5,000 or less, more preferably 2,000 or less.

The (D1) decane coupling agent preferably has a reactive functional group bonded to an organic compound and reacts with a functional group such as (A) an acrylic copolymer or (B) an epoxy-based curable component. Examples thereof include epoxy groups other than glycidoxy or epoxy propoxy groups. And an amino group, a (meth) propylene fluorenyloxy group, a vinyl group other than a (meth) propylene methoxy group, a mercapto group, etc. Among them, preferred are a glycidoxy group and an epoxy group.

These reactive functional groups may also be directly bonded to a ruthenium atom, or may be bonded to a ruthenium atom through a hydrocarbon group or the like, for example, may also be a propylene-glycidoxypropyl epoxide propoxy group C1~ The C4 alkyl group is directly bonded to a ruthenium atom.

Further, the (D1) decane coupling agent may have an alkyl group having a carbon number of 1 to 4 or a phenyl group which is directly bonded to a methyl group of a halogen atom, or the like.

Specific examples of the (D1) decane coupling agent include an oligomer of a product obtained by condensing one or more of the following compounds by hydrolysis and dehydration condensation of an alkoxy group: γ- Glycidoxypropyltrimethoxydecane, γ-glycidoxypropyltriethoxydecane, γ-glycidoxypropylmethyldiethoxydecane, γ-(methacryl) a low molecular decane compound having 2 or 3 alkoxy groups and having at least one of the above reactive functional groups; having 2 or 3 alkoxy groups, having no such reactive functional group; a low molecular decane compound having four alkoxy groups, such as tetramethoxy decane or tetraethoxy decane.

In the film for forming a protective film, the content of the (D1) decane coupling agent is preferably from 0.01 to 7.0% by mass, more preferably from 0.1 to 2.0% by mass, based on the total mass (calculated as solid content) of the film for forming a protective film. .

When the content of the film for forming a protective film is heat-cured by setting the content to be equal to or higher than the above lower limit value, the (D1) decane coupling agent is sufficiently bonded to the surface of the substrate to be bonded, and as a result, high adhesion can be exhibited. When the content is set to be equal to or less than the above upper limit, the surface tension of the film for forming a protective film can be prevented from increasing, and when a film is formed, shrinkage or the like can be prevented. In addition, protection The film for film formation remains in the adherend in this manner, and the support sheet described later can be easily peeled off from the film for forming a protective film, which is less likely to cause troubles in manufacturing and processing.

The film for forming a protective film of the present invention may contain, in addition to the components (A) to (C) and (D1) described above, (D2) a low molecular weight decane coupling agent (E) and a coloring agent (E). F) Any one or more of a hardening accelerator and (G) other additives.

<(D2) low molecular weight decane coupling agent>

The film for forming a protective film may contain a (D2) low molecular weight decane coupling agent having a molecular weight of less than 300 in addition to the (D1) decane coupling agent having a molecular weight of 300 or more.

(D2) The low molecular weight decane coupling agent has a reactive functional group bondable to the surface of the inorganic material, and a reactive functional group bondable to the organic compound. (D2) The low molecular weight decane coupling agent preferably contains an alkoxy group as a reactive functional group capable of bonding to the surface of the inorganic material, and the alkoxy equivalent is preferably set to 13 mmol/g or less. Further, the (D2) low molecular weight decane coupling agent may have a reactive functional group bonded to an organic compound, preferably (A) an acrylic polymer, (B) an epoxy-based curable component, or the like. Examples of the functional group reactive group include an epoxy group other than a glycidoxy group and a glycidoxy group, an amine group, a (meth)acryloxy group, and a vinyl group other than a (meth)acryloxy group.巯基等. Among them, preferred are a glycidoxy group and an epoxy group.

Specific examples of the (D2) low molecular weight decane coupling agent include γ-glycidoxypropyltrimethoxydecane, γ-glycidoxypropyltriethoxydecane, and γ-glycidoxypropoxide. Propylmethyldiethoxy decane, --(3,4-Epoxycyclohexyl)ethyltrimethoxydecane, γ-(methacryloylpropyl)trimethoxydecane, N-phenyl-γ-aminopropyltrimethoxy Decane, γ-ureidopropyltriethoxydecane, N-6-(aminoethyl)-γ-aminopropylmethyldiethoxydecane, γ-mercaptopropyltriethoxydecane, Γ-mercaptopropylmethyldimethoxydecane, vinyltriethoxydecane, and the like.

In the present invention, by blending the (D2) low molecular weight decane coupling agent, it is possible to ensure high adhesion even after storage for a long period of time, and the storage stability is excellent.

That is, the (D2) low molecular weight decane coupling agent is not easily hydrolyzed by the low reactivity, and the alkoxy group is likely to remain after storage for a certain period of time. Further, after the film for forming a protective film is formed, a part of the alkoxy group of the (D2) low molecular weight decane coupling agent undergoes a condensation reaction between the molecules and is polymerized after a predetermined storage period. Therefore, the (D2) low molecular weight decane coupling agent is difficult to immediately increase the adhesion after the production, but after the storage for a certain period of time, the bond to the surface of the adherend can be strengthened similarly to the high molecular weight (D1) decane coupling agent. Therefore, even after the long period of time, even if the adhesion of the (D1) decane coupling agent is lowered, by blending the (D2) low molecular weight decane coupling agent, an appropriate adhesion of the entire film for forming a protective film can be maintained.

In order to exert such an effect, the mass ratio (D2/D1) of the (D2) low molecular weight decane coupling agent to the (D1) decane coupling agent having a molecular weight of 300 or more is preferably 0.1 to 10, more preferably 0.2 to 5, further Good is 1.1~3.

<(E) colorant>

When the semiconductor wafer is mounted on a device, the film for protective film formation preferably contains (E) a colorant in order to shield infrared rays generated by the surrounding device and to prevent erroneous operation of the semiconductor wafer. Again, hardening The protective film obtained by the film for protective film formation can be improved by the (E) coloring agent by the identification of the character of a printed product number, a mark, etc.. That is, the product number or the like is printed by the laser marking method on the back surface of the protective film on which the semiconductor wafer is formed. In this case, the contrast between the printed portion and the non-printed portion is made by causing the protective film to contain (E) the colorant. Become bigger and improve recognition.

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

Among these, a black pigment is preferred, which is excellent in shielding properties by electromagnetic waves and infrared rays, and can further enhance the recognition by the laser marking method. As the black pigment, carbon black, iron oxide, manganese dioxide, aniline black, activated carbon or the like can be used, but it is not limited thereto. From the viewpoint of improving the reliability of the semiconductor wafer, it is particularly preferable to be carbon black. (E) The coloring agent may be used alone or in combination of two or more.

(E) The blending amount of the colorant is preferably from 0.01 to 25% by mass, and more preferably from 0.03 to 15% by mass, based on the total mass (calculated as solid content) of the film for forming a protective film.

<(F) hardening accelerator>

In order to adjust the curing rate of the protective film forming layer, the film for forming a protective film may further contain (F) a curing accelerator.

Preferred examples of the hardening accelerator include triethylene glycol diamine, dimethylbenzylamine, triethanolamine, dimethylamine ethanol, and dimethyl (dimethylaminomethyl) phenol. Grade 3 amines; 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dimethylolimidazole, 2-phenyl- An imidazole such as 4-methyl-5-hydroxymethylimidazole; an organic phosphine such as tributylphosphine, diphenylphosphine or triphenylphosphine; tetraphenylphosphonium tetraphenylborate, triphenylphosphine A tetraphenylboron salt such as tetraphenylborate. These may be used alone or in combination of two or more.

It is preferable to contain 0.01 to 10 parts by mass of the (F) hardening accelerator, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the (B) epoxy-based curable component. By containing the above-mentioned range of (F) hardening accelerator, the film for forming a protective film has excellent adhesion characteristics even when exposed to high temperature and high humidity, and high reliability can be achieved even under severe conditions. Sex.

<(G) Other Additives>

Examples of other additives which may be contained in the film for forming a protective film include a crosslinking agent, a phase solvent, a leveling agent, a plasticizer, an antistatic agent, an antioxidant, an ion trapping agent, a gettering agent, and a chain. The transfer agent, the energy ray polymerizable compound, the photopolymerization initiator, and the like are not particularly limited thereto. The film for forming a protective film can be appropriately adjusted in phase by blending, for example, a phase solvent, and appropriately adjusting the compatibility of the phase rich in the component (A) with the phase of the cured product rich in the component (B). structure.

<gloss value>

The film for forming a protective film is preferably at least one surface of the protective film obtained by curing, and has a gloss value of 20 or more as measured according to JIS Z 8741. In the film for forming a protective film, when the opposite surface of the surface having a gloss value of 20 or more is bonded to the wafer and cured, the printed surface of the protective film by the laser mark becomes The gloss value is 20 or more. Therefore, the surface of the laser printing becomes smooth, the contrast between the printing portion and the non-printing portion is improved, and the visibility of the printed portion is improved.

Since the contrast is improved and the recognition of the characters is improved, the gloss value is preferably 27 or more. Further, the gloss value is not particularly limited, but is preferably 45 or less.

In addition, the gloss value is not particularly limited, and is adjusted according to, for example, the amount of the epoxy group-containing monomer or the alkyl group having 4 or more carbon atoms, and the component (A). The adjustment of the content of the component (B), the choice of the type of the filler, the adjustment of the content or particle diameter of the filler, or the addition of other additives may be appropriately adjusted.

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, still more preferably 7 to 200 μm.

[Composite sheet for forming a protective film]

In general, the film for forming a protective film of the present invention is formed on a support sheet in a peelable manner, and is used as a composite sheet for forming a protective film of a laminate. The film for forming a protective film can be formed in the same shape as the support sheet. In addition, the composite film for forming a protective film may have a configuration in which a film for forming a protective film is laminated on a support sheet having a larger size than a film for forming a protective film (hereinafter referred to as "preformed structure"), wherein the protective film is used. The formation film is formed into a shape that can completely include the shape of the wafer or the shape of the wafer.

The supporting sheet supports the film for forming a protective film, and 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, or the like can be used. Film, polyethylene terephthalate film, polyethylene naphthalate film , polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate copolymer film, ionic polymer resin film, ethylene/(meth)acrylic copolymer film, ethylene/(meth)acrylic acid A film of an ester copolymer film, a polystyrene film, a polycarbonate film, a polyimide film, a fluororesin film, or the like. In addition, such crosslinked films can also be used. Furthermore, it may be such a laminated film. Further, a film obtained by coloring these may also be used.

The surface of the support sheet on the side of the film for forming a protective film may be appropriately subjected to a release treatment. Examples of the release agent to be used in the release treatment include an alkyd type, a polyoxymethylene type, a fluorine type, an unsaturated polyester type, a polyolefin type, a wax type, and the like; and an alkyd type, a polyfluorene type, and a fluorine type. The release agent is preferred because it has heat resistance.

Further, in the composite sheet for forming a protective film, a peeling sheet having a light release property may be bonded to the opposite surface of the film for forming a protective film on the side of the support sheet, and the film for forming a protective film may be protected by the release sheet. .

The film for forming a protective film is obtained by coating and drying a composition for forming a protective film on a support sheet, and the composition for forming a protective film is mixed in an appropriate solvent or in a solvent-free manner at an appropriate ratio. to make. Further, the support sheet may be formed by applying a composition for forming a protective film to another engineering film, drying, forming a film, and appropriately transferring it to a support sheet or the like. The engineered film can also be used as the above-mentioned release sheet without being removed thereafter.

Further, the film may be laminated by wet lamination, dry lamination, hot melt lamination, melt extrusion lamination, co-extrusion processing, or the like to adjust the surface tension of the support sheet. That is, it is also possible to manufacture a laminate As a supporting sheet, the laminated system is formed by laminating a film having at least one surface tension in a preferred range of the surface of the supporting sheet which is in contact with the film for forming a protective film, and the other film, so that the surface becomes a protective film. The film is brought into contact with the surface.

Further, an adhesive sheet formed by forming an adhesive layer on the above film may be used as the support sheet. In this case, the film for forming a protective film is laminated on the adhesive layer provided on the support sheet. In such a configuration, in particular, when the film for forming a protective film or the wafer on the protective film is sliced into a wafer on a composite sheet for forming a protective film, the fixing property of the wafer and the wafer is changed. It is excellent, so it is better. By forming the adhesive layer as a re-adhesive adhesive layer, it is preferable to separate the film for forming a protective film or the protective film from the support sheet. The re-adhesive adhesive layer is preferably one which has a weak adhesiveness which can adhere to the film for forming a protective film, and an energy ray hardenability which reduces the adhesive force by energy ray irradiation. Specifically, the re-adhesive adhesive layer can be obtained by various conventionally known adhesives (for example, rubber-based, acrylic-based, polyfluorene-based, urethane-based, vinyl ether-based, and the like). It is formed by an adhesive having 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 sheet for forming a protective film is formed into a pre-formed structure, the energy ray is irradiated in a region where the protective film-forming film is laminated, and the adhesiveness is first lowered. On the other hand, in other areas, no energy line irradiation is performed. For example, for the purpose of the work of the jig, it is preferable to maintain high viscosity all the time. Focus on. It is performed in such a manner that only the other regions are not irradiated with the energy ray, and for example, the energy ray shielding layer may be provided by printing or the like on the region corresponding to the other region of the supporting sheet, or the energy ray may be irradiated from the supporting sheet side. Further, in order to obtain the same effect, a region in which the film for forming a protective film on the adhesive layer is laminated on the adhesive sheet is further laminated, and a re-peelable adhesive having a shape similar to that of the film for forming a protective film is further laminated. The composition of the agent layer. As the film for a re-peelable adhesive, the same as described above can be used.

When the film for forming a protective film is not formed in advance, the peripheral portion of the surface of the film for forming a protective film (the surface in contact with the adherend) may be fixed to other jigs such as a ring frame. In addition, an adhesive layer and a double-sided tape are provided. When the film for forming a protective film is formed by molding in advance, an adhesive layer may be additionally provided in order to fix other jigs such as a ring frame in a region where the film for protective film formation in the peripheral portion of the support sheet is not laminated. Layer, double-sided tape.

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

The film for forming a protective film is attached to a member to be bonded such as a semiconductor wafer or a semiconductor wafer, and then thermally cured to be used as a protective film. In the case where the film for forming a protective film is attached to the adherend as a composite sheet for forming a protective film, first, when the film is protected by the release sheet, the release sheet is peeled off, and then formed on the protective film. After the laminate of the film and the support film is attached to the adherend, the support sheet is peeled off from the film for forming a protective film.

In the following, a method for using a film for forming a protective film will be described. The film for forming a protective film is used on the back side of a semiconductor wafer. An example of a wafer with a protective film is manufactured for use, but is not limited to the examples shown below.

First, in the present method, 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 substrate sheet is attached to the back surface of the semiconductor wafer. Thereafter, the support sheet is peeled off from the film for forming a protective film, and then a 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.

In addition, the semiconductor wafer may be a germanium wafer or a compound semiconductor wafer such as gallium/arsenic. Further, the semiconductor wafer is formed by forming a circuit on its surface and appropriately polishing the back surface thereof to form a thickness of about 50 to 500 μm.

Next, the circuit formed on the surface of the wafer is diced one by one for the laminated body of the semiconductor wafer and the protective film. The dicing is performed by simultaneously cutting the wafer and the protective film, and dividing the laminated body of the semiconductor wafer and the protective film into a plurality of wafers by dicing. In addition, the cutting of the wafer is performed by a general method of using a diced sheet. Next, the cut wafer is picked up by a general means such as a jig, and a semiconductor wafer (a wafer with a protective film) having a protective film on the back surface is obtained.

Further, the method of manufacturing the semiconductor wafer is not limited to the above examples, and for example, the peeling of the support sheet may be performed after the heat curing of the protective film, or may be performed after the cutting. Further, in the case where the peeling of the support sheet is performed after the cutting, the support sheet can function as a cut sheet. Further, the film for forming a protective film may be thermally cured or may be subjected to dicing.

[wafer with protective film]

The protective film-attached wafer of the present invention can be obtained, for example, by the above-described production method, comprising a semiconductor wafer and a protective film laminated on the back surface of the semiconductor wafer; and the protective film is formed by curing the protective film forming film. It protects the back of the wafer. Further, it is preferable that the surface of the protective film opposite to the surface on the side of the semiconductor wafer has a gloss value of 20 or more as measured by JIS Z 8741.

A semiconductor device can be manufactured by flip-chip bonding a wafer with a protective film onto a substrate or the like. Further, the wafer with the protective film can be manufactured 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 in the present invention are as follows.

(1) Weight average molecular weight (Mw)

The weight average molecular weight Mw in terms of standard polystyrene was measured by a gel permeation chromatography (GPC) method.

Measuring device: The high-speed column "TSK guard column H _XL -H", "TSK Gel GMH _XL ", and "TSK Gel G2000 H _XL " (all of which are manufactured by Tosoh Corporation) are connected in this order to Tosoh Corporation. The high-speed GPC device "HLC-8120GPC" was measured.

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

(2) Reliability assessment

The film for forming a protective film of the composite sheet for forming a protective film which has been peeled off from the release sheet is peeled off to 70° C., and is attached to the warp by using Tape Mounter (Adwill RAD-3600 F/12, manufactured by LINTEC Co., Ltd.). #2000 Grinding surface of a polished wafer (200 mm diameter, thickness 280 μm). Next, after the support sheet was peeled off, the film for forming a protective film was cured by heating at 130 ° C for 2 hours to form a protective film on the germanium wafer. Then, a dicing tape (Adwill D-676H manufactured by LINTEC Co., Ltd.) was attached to the side of the protective film, and it was cut into a size of 3 mm × 3 mm using a cutting device (manufactured by DISCO Co., Ltd., DFD651) to obtain a protection for reliability evaluation. Film wafer.

First, the wafer with the protective film for reliability evaluation described above is processed under the condition (precondition) which mimics the process of actually mounting the semiconductor wafer. Specifically, the wafer with the protective film was baked at 125 ° C for 20 hours, and then placed at 85 ° C, 85% RH for 168 hours to absorb moisture, followed by preheating at 160 ° C, peak temperature 260 The IR reflow furnace under the conditions of °C and heating time of 30 seconds was passed 3 times. A wafer with 25 protective films treated under such necessary conditions was placed in a thermal shock device (TSE-11-A, manufactured by ESPEC Co., Ltd.), and repeated 1000 times at -65 ° C for 10 minutes. The cycle was maintained at 150 ° C for 10 minutes.

Thereafter, 25 wafers with a protective film were taken out from the thermal shock device to evaluate the reliability. Specifically, the scanning type ultrasonic flaw detection apparatus (Hye-Focus manufactured by Hitachi Construction Machinery Co., Ltd.) and the cross-sectional observation are used to evaluate the floating/peeling of the joint portion between the wafer and the protective film, and the crack in the protective film. If there is any, if there is floating, peeling or cracking, it is judged as not Good (NG). The number of NGs in the 25 wafers is shown in Table 3.

(3) Gloss value

The film for forming a protective film of the composite sheet for forming a protective film which has been peeled off from the release sheet is attached to the film by heating at 70 ° C while using Tape Mounter (Adwill RAD-3600 F/12, manufactured by LINTEC Co., Ltd.). Grinding surface of the wafer (200 mm diameter, thickness 280 μm) polished by #2000. Next, after the support sheet was peeled off, the film for forming a protective film was cured by heating at 130 ° C for 2 hours to form a protective film on the germanium wafer. The specular gloss of 60 degrees on the surface of the protective film was measured as the gloss value by the following measuring apparatus and measurement conditions.

Measuring device: VG 2000 Nippon Denshoku Industries Co., Ltd.

Measurement conditions: According to JIS Z 8741.

Example 1

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

(A) Acrylic copolymer: copolymerized with 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 a weight average molecular weight (Mw) of 370,000 and a glass transition temperature (Tg) of 7 ° C

(B) epoxy-based hardening component

Epoxy compound: bisphenol A epoxy resin (made by Nippon Shokubai Co., Ltd., BPA-328), dicyclopentadiene epoxy resin (made by Dainippon Ink and Chemicals Co., Ltd., EPICLON HP-7200HH)

Thermal hardener: dicyandiamide (made by ADEKA Co., Ltd., ADEKA HARDENER 3636AS)

(C) Filler: fused silica filler with an average particle size of 8 μm (cerium oxide filling Material, Longsen company, will SV-10 physical smasher)

(D1) decane coupling agent: oligo-type decane coupling agent (X-4, 56-methoxy equivalent of X-41-1056, molecular weight of 500-1500, having a glycidoxyalkyl group) Reactive functional group)

(D2) Low molecular weight decane coupling agent: γ-glycidoxypropyltriethoxydecane (KBE-403 methoxy equivalent of 8.1 mmol/g, molecular weight 278.4), γ-ring Oxypropoxypropyltrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd. KBM-403 methoxy equivalent 12.7 mmol/g, molecular weight 236.3)

(E) Colorant: carbon black (manufactured by Mitsubishi Chemical Corporation, MA600, average particle diameter: 28 nm)

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

The protective film-forming composition obtained by blending each of the above materials in the ratio shown in Table 1 was diluted with methyl ethyl ketone, and applied to a polyethylene terephthalate film which was subjected to release treatment ( The peeling-treated surface of the support sheet made of LINTEC Co., Ltd., SP-PET 5011, thickness 50 μm) was dried to a thickness of 25 μm, and dried at 100 ° C for 3 minutes to form a protective film on the support sheet. film. Then, a release sheet (SP-PET 3811, thickness: 38 μm, manufactured by LINTEC Co., Ltd.) was laminated on the film for forming a protective film to obtain a composite sheet for forming a protective film of Example 1.

Example 2, 3, Comparative Example 1~5

As the (A) acrylic copolymer, except for the materials shown in Table 2 Except for the part, it was carried out in the same manner as in the first embodiment. Further, the weight average molecular weight (Mw) and the glass transition temperature (Tg) of the (A) acrylic copolymer of each of the examples and the comparative examples are shown in Table 2.

Comparative Example 6

As shown in Tables 1 and 2, as a decane coupling agent, a (D1) decane coupling agent having a molecular weight of 300 or more is not blended, and only a (D2) low molecular weight decane coupling agent (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.) is blended. The same procedure as in Example 2 was carried out except that 1 part by mass was used.

With respect to each of Examples 1 to 3 and Comparative Examples 1 to 6, the reliability was evaluated, and the gloss value was also measured. The results are shown in Table 3.

As shown in Table 3, in the examples 1 to 3, the (A) acrylic polymer contains 8 mass% or less of an epoxy group-containing monomer or no epoxy group-containing monomer as a constituent sheet. In the case where the glass transition temperature is -3 ° C or higher, the phase separation property of the cured product of the component (A) and the component (B) is excellent, and the reliability of the wafer with the protective film is also excellent. In addition, in the examples 1 and 2, since the (A) acrylic polymer contains 8% by mass or less of an epoxy group-containing monomer as a constituent monomer, the gloss value is 20 or more, and printing by laser printing is performed. The recognition is also getting better.

On the other hand, in Comparative Examples 1, 2, and 5, since the glass transition temperature of the (A) acrylic polymer was less than -3 ° C, it was estimated that the protective film was deformed by heat stagnation, and the reliability of the wafer with the protective film could not be obtained. Fully upgraded. Further, in Comparative Examples 3 and 4, since the (A) acrylic polymer contains a large amount of the epoxy group-containing monomer as a constituent monomer, the phase separation property is lowered, and the reliability of the wafer with the protective film is lowered. In addition, in Comparative Example 6, since the film for forming a protective film does not contain the (D1) decane coupling agent having a molecular weight of 300 or more, the adhesion to the semiconductor wafer cannot be sufficiently improved, and the reliability is sufficiently improved.

Claims (7)

A film for forming a protective film for forming a film for forming a protective film for protecting a protective film of a semiconductor wafer, wherein the film for forming a protective film contains (A) an acrylic polymer, (B) an epoxy-based curable component, (C) a filler and (D1) a decane coupling agent; the monomer constituting the (A) acrylic polymer does not contain an epoxy group-containing monomer, or contains a ring in an amount of 8% by mass or less based on the total of the monomers. The monomer of the oxy group, and the glass transition temperature of the (A) acrylic polymer is -3 ° C or higher; and the molecular weight of the (D1) decane coupling agent is 300 or more. The film for forming a protective film according to claim 1, wherein the monomer constituting the (A) acrylic polymer contains an alkyl (meth)acrylate. The film for forming a protective film according to claim 2, wherein the single system constituting the (A) acrylic polymer contains the alkyl group having a carbon number of 4 or more (methyl) in an amount of 12% by mass or less based on the total of the monomers. Alkyl acrylate. The film for forming a protective film according to claim 3, wherein the alkyl group has a carbon number of 4 or more (meth)acrylic acid alkyl ester (butyl) (meth)acrylate. The film for forming a protective film according to any one of claims 1 to 4, further comprising (E) a colorant. The film for forming a protective film according to any one of claims 1 to 5, wherein the (D1) decane coupling agent is a compound having an alkoxy equivalent of more than 13 mmol/g. A protective film-attached wafer comprising a semiconductor wafer and a protective film provided on a protective film of the semiconductor wafer; wherein the protective film is formed by curing a film for forming a protective film; Further, the film for forming a protective film contains (A) an acrylic polymer, (B) an epoxy-based curable component, (C) a filler, and (D1) a decane coupling agent; and a monomer constituting the (A) acrylic polymer. The epoxy group-free monomer is not contained, or the epoxy group-containing monomer is contained in an amount of 8% by mass or less based on the total of the monomers, and the glass transition temperature of the (A) acrylic polymer is -3 ° C or higher; (D1) The molecular weight of the decane coupling agent is 300 or more.