TW201433595A - Protective-membrane-forming film - Google Patents

Abstract

This protective-membrane-forming film, which is used to form a protective membrane that protects a semiconductor chip, contains an acrylic polymer (A), a curable epoxy component (B), and a filler (C). Epoxy-group-containing monomers constitute no more than 8% of the total mass of the monomers constituting the acrylic polymer (A). The glass transition temperature of the acrylic polymer (A) is greater than or equal to -3 DEG C, and at least one surface of the protective membrane obtained by curing this protective-membrane-forming film has a gloss value of at least 20 as measured in accordance with JIS Z 8741.

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, a composition in which two components are phase-separated is transferred to a protective film for a wafer, and the reliability of a wafer with a protective film is improved, but there is a so-called Other problems such as the recognition of characters such as laser printing are likely to be deteriorated.

The present invention has been made in view of the above problems, and it is an object of the invention to provide a film for forming a protective film which is capable of obtaining a highly reliable protective film wafer and capable of forming a laser. A protective film with excellent visibility for printed characters.

In order to solve the above problems, the inventors of the present invention have focused on the acrylic polymer of the resin for forming a protective film, and found that the monomer constituting the acrylic polymer contains an epoxy group-containing monomer. Further, the above-described problems can be solved by setting the glass transition temperature of the acrylic polymer to a predetermined range while adjusting the blending ratio within a predetermined range, and the following invention is completed.

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

(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. The component and the (C) filler; the single system constituting the (A) acrylic polymer contains the epoxy group-containing monomer in an amount of 8% by mass or less of the total monomers, and (A) the acrylic polymer The glass transition temperature is -3 ° C or higher, and the gloss value measured by JIS Z 8741 is at least 20 on at least one side of the protective film obtained by curing the film for forming a protective film.

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

(3) The film for forming a protective film according to the above (1) or (2), wherein the single system comprising the (A) acrylic polymer further contains an alkyl (meth)acrylate.

The film for forming a protective film according to any one of the above aspects (1), wherein the single system comprising the (A) acrylic polymer is contained in an amount of 12% by mass or less based on the total of the monomers. The alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms.

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

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

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

(8) A wafer with a protective film which is provided with a protective film of 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 protection is performed. The film for film formation contains (A) an acrylic polymer, (B) an epoxy-based curable component, and (C) a filler; and a single system constituting the (A) acrylic polymer to constitute 8 mass% of all monomers. The ratio of the following contains an epoxy group-containing monomer, and (A) the acrylic polymer has a glass transition temperature of -3 ° C or more; the surface of the protective film opposite to the surface of the semiconductor wafer is JIS Z 8741 The measured gloss value was 20 or more.

According to the present invention, it is possible to provide a film for forming a protective film which can provide a highly reliable protective film-containing wafer and can form a protective film excellent in visibility of a letter printed by laser.

[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) Filler.

<(A) Acrylic Polymer>

(A) an acrylic polymer-based component which imparts flexibility and film-forming property to a film for forming a protective film and a protective film, which is obtained by copolymerizing an epoxy group-containing monomer and another monomer, and contains a ring. The ratio of the monomer of the oxy group is 8% by mass or less based on the total of the monomers constituting the (A) acrylic polymer. Specifically, the single system constituting the (A) acrylic polymer includes one or more selected from the group consisting of an epoxy group-containing (meth) acrylate and a non-acrylic epoxy group-containing monomer. A monomer of an epoxy group, and various (meth) acrylates having no epoxy group, and/or a monomer other than an epoxy group which 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 with the cured product of the component (B) is improved, and the phase separation structure to be described later is less likely to be formed, and the reliability of the wafer with the protective film is lowered. On the other hand, like When the acrylic polymer (A) does not contain the epoxy group-containing monomer at all in the constituent monomer, the gloss value of the protective film due to the progress of phase separation becomes excessively lowered, and it becomes difficult to maintain the latter. The range of gloss values. That is to say, if the epoxy group-containing monomer is not contained at all, fine concavities and convexities due to the progress of phase separation occur on the surface of the protective film, and as a result, scattering of reflected light on the surface of the protective film is caused. Therefore, the gloss value becomes small, and the visibility of the laser printed portion is lowered.

From such a viewpoint, the content of the epoxy group-containing monomer is preferably 0.1% by mass or more, and more preferably 1% by mass or more based on the total mass of all the monomers. Further, in order to improve the gloss value and to further improve the reliability, it is particularly preferably 3% by mass or more. Further, 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 glycidyl (meth) acrylate and β-methyl glycidyl (meth) acrylate. (3,4-epoxycyclohexyl)methyl acrylate, 3-epoxycyclo-2-hydroxypropyl (meth) acrylate, etc., as a non-acrylic epoxy group-containing monomer For example: glycidyl butenoate, allyl glycidyl ether, and the like. The epoxy group-containing monomer is preferably an epoxy group-containing (meth) acrylate.

Examples of the other monomer in the (A) acrylic polymer include an alkyl (meth)acrylate and another (meth)acrylic acid derivative.

Among the monomers constituting the (A) acrylic polymer, the other monomer is preferably an alkyl (meth)acrylate. Accordingly, it is easy to adjust (A) the glass 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. Glass transfer 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.

The monomer constituting the (A) acrylic polymer preferably contains the alkyl group in the alkyl (meth) acrylate 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 a carbon number of 4 or more. According to this, it is easy to optimize the gloss value while adjusting the glass transition temperature to -3 ° C or higher. In order to optimize the gloss value and improve the reliability, the content of the alkyl (meth)acrylate 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. Further, the alkyl (meth)acrylate 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 as another (meth)acrylic acid derivative. 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, as the other monomer, a non-acrylic epoxy group-free monomer such as styrene, ethylene, vinyl ether or vinyl acetate as described above. .

In order to impart flexibility and film formability to the film for forming a protective film, and to easily make the gloss value to be described later 20 or more, the weight average molecular weight (Mw) of the (A) acrylic polymer is preferably 10,000 or more. Further, the above weight average molecular weight is more preferably from 15,000 to 1,000,000, further Good is 20,000~500,000. 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 (Tg) 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 print recognition property 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 suppressing a monomer having an epoxy group to a small amount so that a phase rich in the component (A) in the protective film and a phase rich in a hardened component rich in the component (B) described later are easily obtained. Separate and improve 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 When the size of the phase separation structure is less than the decomposition energy of the Raman spectroscopy, the hardness measured by the Tapping Mode of the SPM (scanning probe microscope) is used as an index, and it is estimated that the harder one is rich (B). The phase of the hardened component of the component is softer and is the phase rich in the component (A). 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. Furthermore, by limiting the blending amount of the component (B) as described above to a predetermined In the range below the upper limit value, the phase rich in the component (A) can be easily made into a continuous phase, the reliability of the semiconductor wafer can be improved, and the gloss value can be easily improved.

In addition, the ratio of the (B) epoxy-based curable component to the total mass (calculated as solid content) of 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, the content of the thermosetting agent is preferably from 0.1 to 100 parts by mass, more preferably from 0.5 to 50 parts by mass, even more preferably from 1 to 20 parts by mass, per 100 parts by mass of the epoxy compound. 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, by applying a laser mark on the protective film (the method of removing the surface of the protective film by laser light for printing), the portion (printing portion) which is removed by the laser light diffuses the reflected light due to (C) the filler is exposed. , the comparison with the non-printed part becomes identifiable.

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.

Further, from these viewpoints, the average particle diameter of the filler is more preferably 0.2 to 10 μm, still more 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.

The film for forming a protective film of the present invention may contain the following (D) coloring agent, (E) coupling agent, (F) curing accelerator, and (G) in addition to the components (A) to (C) described above. Any one or more of the other additives.

<(D) colorant>

The film for forming a protective film preferably contains (D) a colorant when the semiconductor wafer is mounted on a device so as to shield infrared rays generated by the surrounding device and to prevent erroneous operation of the semiconductor wafer. Further, on the protective film obtained by curing the film for forming a protective film, the printed article number The recognizability of the characters such as marks and symbols can be improved by containing (D) a coloring agent. That is, in the back surface of the protective film on which the semiconductor wafer is formed, the product number or the like is printed by a general laser marking method, and the contrast of the printed portion and the non-printed portion is made larger by including the protective film (D) coloring agent. And enhance recognition.

As the (D) 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. (D) The coloring agent may be used alone or in combination of two or more.

(D) The blending amount of the coloring agent 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.

<(E) coupling agent>

The (E) coupling agent may also be blended in the film for forming a protective film.

The (E) coupling agent is preferably a decane coupling agent having an alkoxy group such as a methoxy group or an ethoxy group. Further, it is preferable to use a functional group having a functional group such as (A) an acrylic polymer or (B) an epoxy-based curable component, and having a reactive functional group other than an alkoxy group, as the (E) coupling agent. Combination Things. Examples of the reactive functional group include an epoxy group other than a glycidoxy group, a glycidoxy group, an amine group, a (meth)acryloxy group, and a (meth)acryloxy group. Base, base, etc. Among them, preferred are a glycidoxy group and an epoxy group.

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

Specific examples of the low molecular weight decane coupling agent include γ-glycidoxypropyltrimethoxydecane, γ-glycidoxypropyltriethoxydecane, and γ-glycidoxypropyl group. Methyldiethoxydecane, β-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, γ-(methacryloylpropyl)trimethoxynonane, N-phenyl-γ -Aminopropyltrimethoxydecane, γ-ureidopropyltriethoxydecane, N-6-(aminoethyl)-γ-aminopropylmethyldiethoxydecane, γ-mercapto Propyltriethoxydecane, γ-mercaptopropylmethyldimethoxydecane, vinyltriethoxydecane, and the like.

The oligomer type decane coupling agent is preferably an organopolyoxane having a fluorene skeleton and having an alkoxy group directly bonded to a ruthenium atom.

The content of the (E) coupling agent is preferably from 0.01 to 10.0% by mass, more preferably from 0.1 to 3.0% 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 the like. The chain 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 has a gloss value of at least 20 on at least one surface of the protective film obtained by the above-described combination curing, and the gloss value is measured by JIS Z 8741. For the purposes of the present invention, it The surface opposite to the surface of 20 or more is bonded to the wafer to be hardened, and the printed surface of the protective film by the laser mark has a gloss value of 20 or more. Therefore, in the present invention, 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 selection of the type of the filler, the adjustment of the content of the filler or the particle diameter, 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. Further, the composite sheet for forming a protective film may have a so-called pre-formed structure in which a film for forming a protective film is formed into a shape which completely includes a shape similar to a wafer or a shape of a wafer, and is protected. The film for film formation is laminated on a support sheet having a size larger than that of the film for forming a protective film.

The support sheet is used to support a film for forming a protective film, and for example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film can be used. Membrane, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, poly A urethane film, an ethylene vinyl acetate copolymer film, an ionic polymer resin film, an ethylene/(meth)acrylic copolymer film, an ethylene/(meth)acrylate copolymer film, a polystyrene film, a polycarbonate A film of an ester film, a polyimide film, a fluororesin film or the like. In addition, such crosslinked films can also be used. Further, it may be a laminated film selected from two or more of these. 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.

In addition, it can also be formed by wet lamination, dry lamination, and hot melt. The film is laminated by a melt layer, a melt-extruded laminate, a co-extrusion process, etc. to adjust the surface tension of the support sheet. In other words, a laminate may be produced as a support sheet which is formed by laminating a film having at least one surface tension in a preferred range of the surface of the support sheet which is in contact with the film for forming a protective film, and other films. This surface is brought into contact with the film for forming a protective film.

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 film for forming a protective film is laminated. First, the adhesion is lowered first, and on the other hand, the energy line is not irradiated in other areas. For example, for the purpose of the attachment of the jig, it is preferable to maintain high adhesion at all times. 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, an example in which the film for forming a protective film is used for the back surface protection of a semiconductor wafer to produce a film with a protective film will be described. However, the present invention 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. In addition, the peeling of the support sheet, in the case of performing the cutting, the support sheet can be used as a cut The role of cutting thin slices. 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. The surface of the protective film opposite to the surface on the side of the semiconductor wafer was measured to have 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 feeding speed: 1.0 mL / min, detector : Differential Refractometer

(2) 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 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 the polished surface of the wafer (200mm diameter, thickness 280μm). 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 Industrial Co., Ltd.

Measurement conditions: in accordance with JIS Z 8741

(3) Identification of characters (printability)

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. On the surface of the protective film, four characters of a character having a width of 300 μm or less were printed using a laser printing apparatus (LP-V10U manufactured by Panasonic Device SUNX Co., Ltd., laser wavelength: 1056 nm). The printed protective film surface was confirmed by a digital microscope, and it was confirmed by image whether the printing was readable. When the judgment standard is observed by a digital microscope, when the printing unit is irradiated with direct light, the full reading is indicated as "A". The reading possibility is not clearly indicated as "B", and cannot be read as "F".

(4) 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 cut into a size of 3 mm × 3 mm using a cutting device (DFD651, manufactured by DISCO Co., Ltd.) 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 make it absorb moisture, and then immediately preheated at 160 ° C, peak temperature. The IR reflow furnace at 260 ° C and a heating time of 30 seconds was passed three 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, by means of a scanning ultrasonic flaw detection device ( Hitachi Construction Machinery FINETECH Co., Ltd. Hye-Focus) and cross-sectional observation, evaluate the floating/peeling of the joint between the wafer and the protective film, and the presence or absence of cracks in the protective film. If there is floating, peeling, or cracking, It was judged to be bad (NG). The number of NGs in the 25 wafers is shown in Table 4.

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 (BPA-328, manufactured by Nippon Shokubai Co., Ltd.), dicyclopentadiene epoxy resin (manufactured 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 diameter of 8 μm (manganese dioxide filler, manufactured by Ronson Corporation, physically crushed by SV-10)

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

(E) decane coupling agent: oligomer type decane coupling agent (X-4-56, methoxy equivalent of 17.01 mmol/g, molecular weight 500-1500), γ-glycidoxypropyl propylene Triethoxy decane (KBE-403 methoxy equivalent of 8.1 mmol/g, molecular weight 278.4), γ-glycidoxypropyltrimethoxy 矽 ( (KBM-403 methoxy equivalent of 12.7mmol/g, molecular weight 236.3)

(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, Comparative Examples 1 to 6

The (A) acrylic copolymer was carried out in the same manner as in Example 1 except that the portions shown in Table 2 were used. 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.

Example 3

The (C) component was carried out in the same manner as in Example 2 except that a cerium oxide filler (manufactured by TOKUYAMA Co., Ltd., UF310) having an average particle diameter of 3 μm was used instead of the cerium oxide filler having an average particle diameter of 8 μm.

Example 4

The (C) component was carried out in the same manner as in Example 2 except that a cerium oxide filler (manufactured by ADMATECHS Co., Ltd., SC2050MA) having an average particle diameter of 0.5 μm was used instead of the cerium oxide filler having an average particle diameter of 8 μm.

Example 5, 6

Except that the part of the component (C) was changed as shown in Table 3, the same procedure as in Example 2 was carried out.

Examples 7, 8

Except that part of the blending amount of the components (A) and (B) was changed as shown in Table 3, the same procedure as in Example 2 was carried out.

With respect to each of Examples 1 to 8 and Comparative Examples 1 to 6, the gloss value was measured, and the print visibility and reliability were evaluated. The results are shown in Table 4.

As shown in Table 4, in the examples 1 to 8, the (A) acrylic polymer contains 8% by mass or less of an epoxy group-containing monomer as a constituent monomer, and the glass transition temperature is -3 ° C. As described above, the phase separation property of the phase rich in the component (A) and the phase of the cured product rich in the component (B) is excellent, and the gloss value is also 20 or more, so that the printability and reliability are printed. Both can be excellent.

On the other hand, in Comparative Example 1, since the (A) acrylic polymer does not contain an epoxy group-containing monomer as a constituent monomer, fine irregularities are formed on the surface of the protective film due to phase separation, and as a result, Reflected light scattering from the surface of the protective film. Therefore, the gloss value becomes small, and the print recognition property is deteriorated. Further, in Comparative Examples 2, 3, and 6, since the glass transition temperature of the (A) acrylic polymer was less than -3 ° C, it was presumed that the protective film was deformed by heat stagnation. As the number of NG wafers increases, the reliability of wafers with protective films cannot be sufficiently improved. Further, in Comparative Examples 4 and 5, since the (A) acrylic polymer contains a large amount of the epoxy group-containing monomer as a constituent monomer, the affinity between the component (A) and the component (B) is high, and it is difficult to cause The phase separation, the reliability of the wafer with the protective film becomes low.

Claims (8)

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, And (C) a filler; a single system constituting the (A) acrylic polymer contains an epoxy group-containing monomer in a proportion of 8% by mass or less of the total monomers, and (A) a glass transition of the acrylic polymer The temperature is -3 ° C or higher, and the gloss value measured by JIS Z 8741 is at least 20 on at least one side 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 (A) acrylic polymer is 6 ° C or lower. The film for forming a protective film according to claim 1 or 2, wherein the single system constituting the (A) acrylic polymer further contains an alkyl (meth)acrylate. The film for forming a protective film according to any one of claims 1 to 3, wherein the single system constituting the (A) acrylic polymer has a carbon number of 4 in an amount of 12% by mass or less based on the total of the monomers. The above alkyl (meth)acrylate. The film for forming a protective film according to claim 4, 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 5, wherein the content of the (C) filler is 50% by mass or more of the film for forming a protective film. The film for forming a protective film according to any one of claims 1 to 6, which further comprises (D) a colorant. A protective film wafer having a semiconductor wafer and disposed thereon a protective film of a protective film on a 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 a curable component and (C) a filler; a single system constituting the (A) acrylic polymer contains an epoxy group-containing monomer in an amount of 8% by mass or less based on the total monomers, and (A) an acrylic system The glass transition temperature of the polymer is -3 ° C or higher; the gloss value measured by JIS Z 8741 of the surface of the protective film opposite to the surface on the semiconductor wafer side is 20 or more.