Protective film forming film, composite sheet for protective film forming film, semiconductor chip with protective film, and semiconductor device

Abstract

To provide a protective film-forming film which can form a protective film having excellent flame retardancy and has excellent flexibility before curing, and to provide a protective film-forming composite sheet, a protective film-equipped semiconductor chip, and a semiconductor device using the protective film-forming film.SOLUTION: The protective film-forming film is formed using a resin composition containing (A) a thermoplastic resin, (B) an epoxy resin, (C) an inorganic filler, and (D) a phosphoric acid compound derivative. The content of phosphorus atoms in the resin composition is 0.3 mass% or more based on the solid content (100 mass%) of the resin composition. The content of the phosphoric acid compound derivative (D) in the resin composition is 5.5 mass% or less based on the solid content (100 mass%) of the resin composition. The protective film-forming composite sheet, the protective film-equipped semiconductor chip, and the semiconductor device use the protective film-forming film.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a film for forming a protective film, a composite sheet for forming a protective film, a semiconductor chip with a protective film, and a semiconductor device. [Background technology]

[0002] 2. Description of the Related Art In recent years, semiconductor devices have been manufactured using a mounting method known as the face-down method, in which a semiconductor chip is mounted on a substrate with its circuit surface facing the substrate. In the face-down method, electrodes such as bumps formed on the circuit surface of the semiconductor chip are joined to the substrate, so a protective film may be formed on the back surface of the semiconductor chip to prevent the back surface opposite the circuit surface of the semiconductor chip from being exposed. The protective film protects the semiconductor chip from external impacts during the manufacturing process and after the semiconductor chip is mounted. The protective film can also be used for identifying and decorating the semiconductor chip by laser marking. Furthermore, the protective film can also function as a light-shielding layer to prevent circuit malfunctions.

[0003] The protective film is formed, for example, using a protective film-forming film. As the protective film-forming film, a curable film made of a thermosetting or energy ray-curable resin composition is used from the viewpoints of mechanical strength, heat resistance, etc. The curable protective film-forming film is attached to an object to be protected, such as a semiconductor wafer or a semiconductor chip, and then cured to form a protective film made of the cured product. For example, Patent Document 1 discloses a chip protection film characterized by having a curable protective film-forming layer that has a pencil hardness of 5H or more after curing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-147277 Summary of the Invention [Problem to be solved by the invention]

[0005] Before being attached to an object to be protected, the protective film-forming film is usually punched into the same shape as the object to be protected, the release film that protects the surface is peeled off and removed, and then the protective film-forming film is attached to the surface to be protected of the object to be protected. The protective film-forming film before curing is required to be flexible so that it will not be torn by the mechanical forces applied in each of these processes.

[0006] Recently, the flame retardancy required for electronic components has been increasing from the viewpoint of improving safety. Halogen-based flame retardants have been used to improve the flame retardancy of plastic products, but there is a growing trend to refrain from using halogen-based flame retardants because they are suspected of emitting toxic substances when incinerated. However, according to the investigations of the present inventors, it has been confirmed that when a flame retardant is used as an alternative to a halogen-based flame retardant to make a film for forming a protective film flame retardant, the flexibility before curing required for the film for forming a protective film becomes insufficient. Therefore, it has been difficult to achieve both flexibility before curing and flame retardancy of the protective film formed in the film for forming a protective film.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a film for forming a protective film that can form a protective film with excellent flame retardancy and has excellent flexibility before curing, a composite sheet for forming a protective film using the film for forming a protective film, a semiconductor chip with a protective film, and a semiconductor device. [Means for solving the problem]

[0008] The present inventors have found that the above-mentioned problems can be solved by using a resin composition containing a thermoplastic resin, an epoxy resin, an inorganic filler, and a phosphoric acid compound derivative, and have thus completed the present invention.

[0009] That is, the present invention relates to the following [1] to

[12] . [1] (A) a thermoplastic resin, (B) an epoxy resin, (C) an inorganic filler, and (D) a phosphoric acid compound derivative; A film for forming a protective film formed using a resin composition containing the content of phosphorus atoms in the resin composition is 0.3% by mass or more relative to the solid content (100% by mass) of the resin composition; The film for forming a protective film, wherein the content of the (D) phosphoric acid compound derivative in the resin composition is 5.5% by mass or less relative to the solid content (100% by mass) of the resin composition. [2] The film for forming a protective film according to the above [1], wherein the (D) phosphoric acid compound derivative is a metal phosphinate. [3] The film for forming a protective film according to the above [2], wherein the metal phosphinate is represented by the following general formula (D-1): [ka] (In the formula, R 1 and R 2 each independently represents a substituted or unsubstituted aliphatic hydrocarbon group, or a substituted or unsubstituted aromatic hydrocarbon group. M represents an n-valent metal atom. n represents an integer of 1 to 4. [4] The film for forming a protective film according to any one of the above [1] to [3], wherein the thermoplastic resin (A) is an acrylic resin. [5] A film for forming a protective film according to any one of [1] to [4] above, wherein the content of (C) inorganic filler in the resin composition is 50% by mass or more relative to the solid content (100% by mass) of the resin composition. [6] The film for forming a protective film according to any one of the above [1] to [5], wherein the resin composition further contains (E) a curing accelerator. [7] The film for forming a protective film according to any one of the above [1] to [6], wherein the resin composition further contains (F) a colorant. [8] The film for forming a protective film according to any one of the above [1] to [7], which is attached to the back surface of a semiconductor wafer and is used for producing a semiconductor chip with a protective film. [9] A composite sheet for forming a protective film, having a configuration in which the film for forming a protective film according to any one of [1] to [8] above is sandwiched between two release sheets.

[10] A composite sheet for forming a protective film, comprising a substrate, a pressure-sensitive adhesive layer, and the film for forming a protective film according to any one of [1] to [8] above, in this order.

[11] A semiconductor chip with a protective film, which has a protective film that is a cured product of the film for forming a protective film according to any one of [1] to [8] above.

[12] A semiconductor device having the semiconductor chip with a protective film according to

[11] above. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a film for forming a protective film that can form a protective film with excellent flame retardancy and has excellent flexibility before curing, a composite sheet for forming a protective film using the film for forming a protective film, a semiconductor chip with a protective film, and a semiconductor device. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view showing an example of the configuration of a composite sheet for forming a protective film according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing an example of the configuration of a composite sheet for forming a protective film according to a second embodiment of the present invention. [Figure 3] FIG. 3 is a schematic cross-sectional view showing another example of the configuration of the composite sheet for forming a protective film according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] In this specification, the number average molecular weight (Mn) and the mass average molecular weight (Mw) are values ​​measured by gel permeation chromatography (GPC) in terms of standard polystyrene, and specifically, are values ​​measured based on the method described in the examples.

[0013] In this specification, for preferred numerical ranges (e.g., ranges of content, etc.), the lower and upper limits described in stages can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to form "10 to 60."

[0014] As used herein, "energy rays" refers to electromagnetic waves or charged particle beams that have an energy quantum. Examples of energy rays include ultraviolet rays, radioactive rays, and electron beams. Ultraviolet rays can be irradiated using an electrodeless lamp, a high-pressure mercury lamp, a metal halide lamp, a xenon lamp, a black light, an LED lamp, or the like. Electron beams can be generated by an electron beam accelerator or the like.

[0015] In this specification, "energy ray curable" means a property of being cured by irradiation with energy rays, and "non-energy ray curable" means a property of not being cured even when irradiated with energy rays, and includes thermosetting and non-curing. "Thermosetting" means a property of being cured by heating, and "non-curing" means a property of not being cured by heating or irradiation with energy rays, etc.

[0016] In this specification, for example, "(meth)acrylic acid" refers to both "acrylic acid" and "methacrylic acid," and the same applies to other similar terms.

[0017] In this specification, the "circuit side" of a semiconductor wafer or semiconductor chip refers to the side on which a circuit is formed, and the "back side" of a semiconductor wafer or semiconductor chip refers to the side opposite the circuit side.

[0018] In this specification, the "thickness" of an object refers to the thickness of the entire object, and for example, when the object is made up of multiple layers, it refers to the total thickness of all layers that make up the object. Here, "object" refers to a protective film-forming film, a release film, a substrate, a pressure-sensitive adhesive layer, etc., which will be described later. The thicknesses in this specification are values ​​measured based on the method described in the examples.

[0019] In this specification, the term "solid content" refers to the components contained in the target composition excluding water and dilution solvents such as organic solvents.

[0020] The mechanism of action described in this specification is speculation and does not limit the mechanism by which the effects of the present invention are achieved.

[0021] [Protective film forming film] The protective film-forming film of this embodiment is A film for forming a protective film formed using a resin composition containing (A) a thermoplastic resin, (B) an epoxy resin, (C) an inorganic filler, and (D) a phosphoric acid compound derivative, the content of phosphorus atoms in the resin composition is 0.3% by mass or more relative to the solid content (100% by mass) of the resin composition; In the film for forming a protective film, the content of the (D) phosphoric acid compound derivative in the resin composition is 5.5% by mass or less relative to the solid content (100% by mass) of the resin composition.

[0022] The film for forming a protective film of the present embodiment has at least thermosetting properties. Here, in this specification, the term "film for forming a protective film" refers to the film before curing, and the term "protective film" refers to the film for forming a protective film after curing. The film for forming a protective film of this embodiment is attached to an object to be protected, such as a semiconductor wafer or a semiconductor chip, and then heat-cured to become a protective film that protects the object to be protected from external impacts, etc. In particular, the film for forming a protective film of this embodiment is attached to the back surface of a semiconductor wafer and is useful for producing semiconductor chips with a protective film. The protective film formed from the film for forming a protective film of this embodiment has excellent flame retardancy, and therefore, an object to be protected provided with a protective film formed from the film for forming a protective film of this embodiment has excellent safety. Furthermore, since the film for forming a protective film of this embodiment has excellent flexibility before hardening, the occurrence of tearing and the like when punched into the same shape as the object to be protected is suppressed.

[0023] The film for forming a protective film of this embodiment may consist of only one layer, or may consist of two or more layers. When the film for forming a protective film of this embodiment consists of multiple layers, the layers constituting the multiple layers may be the same as or different from each other.

[0024] In the following description, the resin composition used to form the film for forming a protective film of this embodiment may be referred to as the "resin composition for forming a protective film."

[0025] [Resin composition for forming a protective film] The resin composition for forming a protective film is a resin composition containing (A) a thermoplastic resin, (B) an epoxy resin, (C) an inorganic filler, and (D) a phosphoric acid compound derivative.

[0026] <Phosphorus atom content> In this embodiment, the content of phosphorus atoms in the resin composition for forming a protective film is 0.3% by mass or more with respect to the solid content (100% by mass) of the resin composition for forming a protective film. When the content of phosphorus atoms in the resin composition for forming a protective film is within the above range, the protective film formed from the film for forming a protective film of this embodiment will have excellent flame retardancy. The content of phosphorus atoms in the resin composition for forming a protective film is preferably 0.4 to 1.5 mass%, more preferably 0.5 to 1.3 mass%, and even more preferably 0.55 to 1.0 mass%, from the viewpoints of the flame retardancy of the protective film and the flexibility of the film for forming a protective film before curing.

[0027] Each component contained in the resin composition for forming a protective film will be described in detail below.

[0028] <(A) Thermoplastic resin> By including the thermoplastic resin (A) in the resin composition for forming a protective film, the film for forming a protective film of this embodiment has excellent flexibility before curing and excellent adhesion to the object to be protected. The (A) thermoplastic resin may be used alone or in combination of two or more kinds.

[0029] Examples of the (A) thermoplastic resin include acrylic resin, urethane resin, phenoxy resin, silicone resin, saturated polyester resin, polybutene resin, polybutadiene resin, polystyrene resin, etc. Among these, acrylic resin is preferred.

[0030] The raw material monomer of the acrylic resin preferably contains a (meth)acrylic acid ester. The raw material monomers for the acrylic resin may be used alone or in combination of two or more.

[0031] Examples of (meth)acrylic acid esters include alkyl(meth)acrylates such as methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, butyl(meth)acrylate, pentyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, nonyl(meth)acrylate, decyl(meth)acrylate, undecyl(meth)acrylate, dodecyl(meth)acrylate, tridecyl(meth)acrylate, tetradecyl(meth)acrylate, pentadecyl(meth)acrylate, hexadecyl(meth)acrylate, heptadecyl(meth)acrylate, and octadecyl(meth)acrylate; and cycloalkyl(meth)acrylates such as cyclohexyl(meth)acrylate, isobornyl(meth)acrylate, and dicyclopentanyl(meth)acrylate. cycloalkenyl (meth)acrylates such as dicyclopentenyl (meth)acrylate; cycloalkenyloxyalkyl (meth)acrylates such as dicyclopentenyloxyethyl (meth)acrylate; imide (meth)acrylates; glycidyl group-containing (meth)acrylates such as glycidyl (meth)acrylate; hydroxy group-containing (meth)acrylates such as hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; and substituted amino group-containing (meth)acrylates such as N-methylaminoethyl (meth)acrylate.

[0032] Among these, it is preferable that the raw material monomer of the acrylic resin contains alkyl(meth)acrylate. The number of carbon atoms in the alkyl group constituting the alkyl ester of the alkyl (meth)acrylate is not particularly limited, but is preferably 1-18, more preferably 1-10, and even more preferably 1-4. The alkyl group constituting the alkyl ester of the alkyl (meth)acrylate may be in any form, provided that it can be n-, sec-, tert- or iso-, depending on the carbon position having a free valence. The content of alkyl (meth)acrylate in the raw material monomer of the acrylic resin is not particularly limited, but is preferably 50 to 97 mass%, more preferably 60 to 93 mass%, and even more preferably 70 to 90 mass%, relative to the raw material monomer of the acrylic resin (100 mass%).

[0033] The raw material monomers of the acrylic resin preferably contain a hydroxy group-containing (meth)acrylate together with an alkyl (meth)acrylate. When the raw material monomer of the acrylic resin contains a hydroxy group-containing (meth)acrylate, the content of the hydroxy group-containing (meth)acrylate in the raw material monomer of the acrylic resin is not particularly limited, but is preferably 2 to 50 mass %, more preferably 6 to 40 mass %, and even more preferably 10 to 30 mass %, relative to the raw material monomer of the acrylic resin (100 mass %).

[0034] The raw material monomers for the acrylic resin may or may not contain a monomer other than a (meth)acrylic acid ester. Examples of monomers other than (meth)acrylic acid esters include (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, acryloylmorpholine, styrene, acrylamide, and N-methylolacrylamide.

[0035] The mass average molecular weight (Mw) of the (A) thermoplastic resin is not particularly limited, but is preferably 10,000 to 2,000,000, more preferably 100,000 to 1,500,000, and even more preferably 150,000 to 1,000,000. When the mass average molecular weight (Mw) of the (A) thermoplastic resin is equal to or greater than the lower limit, the shape stability of the film for forming a protective film tends to be better. On the other hand, when the mass average molecular weight (Mw) of the (A) thermoplastic resin is equal to or less than the upper limit, the film for forming a protective film tends to be able to easily conform to the uneven surface of the object to be protected, and the occurrence of voids between the object to be protected and the film for forming a protective film tends to be more suppressed.

[0036] The glass transition temperature (Tg) (hereinafter simply referred to as "Tg") of the (A) thermoplastic resin is not particularly limited, but is preferably -60 to 70°C, more preferably -30 to 50°C, and even more preferably -10 to 20°C. When the Tg of the thermoplastic resin (A) is equal to or greater than the lower limit, the cohesive strength of the film for forming a protective film tends to be better, and when the Tg of the thermoplastic resin (A) is equal to or less than the upper limit, the flexibility and adhesiveness of the film for forming a protective film tend to be improved.

[0037] For example, the Tg of an acrylic resin can be calculated using the Fox formula shown below. 1 / Tg=(W1 / Tg1)+(W2 / Tg2)+…+(Wm / Tgm) (In the formula, Tg is the glass transition temperature of the acrylic resin, Tg1, Tg2, ... Tgm are the glass transition temperatures of the homopolymers of the monomers that are the raw materials for the acrylic resin, and W1, W2, ... Wm are the mass fractions of the respective monomers, provided that W1 + W2 + ... + Wm = 1.) The glass transition temperatures of the homopolymers of each monomer in the Fox equation can be found in the Polymer Data Handbook, Adhesive Handbook, or Polymer Handbook. For example, the Tg of methyl acrylate homopolymer is 10°C, that of 2-hydroxyethyl acrylate homopolymer is -15°C, that of 2-ethylhexyl acrylate is -70°C, and that of 2-ethylhexyl methacrylate is -10°C. Alternatively, Tg can be determined in accordance with JIS K 7121 (2012).

[0038] The (A) thermoplastic resin may have a functional group, such as a vinyl group, a (meth)acryloyl group, an amino group, a hydroxy group, a carboxy group, or an isocyanate group. When the (A) thermoplastic resin has a functional group, the functional group may be bonded to another compound via a (H) crosslinking agent described below, or may be bonded directly to another compound without the use of a (H) crosslinking agent. Bonding the (A) thermoplastic resin to another compound via the functional group via a (H) crosslinking agent or directly tends to improve the reliability of the protective film. The (A) thermoplastic resin having a functional group is preferably an acrylic resin having a functional group, and more preferably an acrylic resin having a hydroxy group as the functional group.

[0039] The content of the (A) thermoplastic resin in the resin composition for forming a protective film is not particularly limited, but is preferably 5 to 80 mass %, more preferably 7 to 50 mass %, and even more preferably 10 to 30 mass %, relative to the solid content (100 mass %) of the resin composition for forming a protective film. When the content of the (A) thermoplastic resin is equal to or greater than the lower limit, the pre-curing flexibility of the film for forming a protective film and its adhesion to the object to be protected tend to be better. When the content of the (A) thermoplastic resin is equal to or less than the upper limit, the flame retardancy, mechanical strength, and heat resistance of the protective film tend to be better.

[0040] <(B) Epoxy resin> By containing (B) epoxy resin in the resin composition for forming a protective film, the film for forming a protective film of this embodiment becomes thermosetting, and a protective film having excellent mechanical strength, heat resistance, etc. can be formed. The (B) epoxy resin may be used alone or in combination of two or more kinds.

[0041] The (B) epoxy resin is preferably an epoxy resin having two or more epoxy groups in one molecule. Examples of the (B) epoxy resin include known ones, such as bisphenol-type epoxy resins such as bisphenol A-type epoxy resins and bisphenol F-type epoxy resins, and hydrogenated products thereof; novolac-type epoxy resins such as phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, and orthocresol novolac-type epoxy resins; aralkyl-type epoxy resins such as phenol aralkyl-type epoxy resins; dicyclopentadiene-type epoxy resins; biphenyl-type epoxy resins; and naphthalene-type epoxy resins. Among these, dicyclopentadiene-type epoxy resins, bisphenol-type epoxy resins, and naphthalene-type epoxy resins are preferred from the viewpoint of the handleability and heat resistance of the protective film-forming film.

[0042] The number average molecular weight (Mn) of the (B) epoxy resin is not particularly limited, but from the viewpoint of the curability of the film for forming a protective film and the mechanical strength and heat resistance of the protective film, it is preferably 200 to 30,000, more preferably 250 to 10,000, and even more preferably 300 to 3,000.

[0043] The epoxy equivalent of (B) epoxy resin is not particularly limited, but from the viewpoint of the curability of the film for forming a protective film and the mechanical strength and heat resistance of the protective film, it is preferably 100 to 1,500 g / eq, more preferably 130 to 1,200 g / eq, and even more preferably 160 to 1,000 g / eq. In this specification, the term "epoxy equivalent" means the number of grams (g / eq) of an epoxy resin containing 1 gram equivalent of epoxy groups, and can be measured according to JIS K 7236:2001.

[0044] The content of (B) epoxy resin in the resin composition for forming a protective film is not particularly limited, but is preferably 2 to 60 mass %, more preferably 4 to 40 mass %, and even more preferably 7 to 20 mass %, relative to the solid content (100 mass %) of the resin composition for forming a protective film. When the content of the (B) epoxy resin is equal to or greater than the lower limit, the curability of the film for forming a protective film, as well as the mechanical strength and heat resistance of the protective film, tend to be better. When the content of the (B) epoxy resin is equal to or less than the upper limit, the flexibility of the film for forming a protective film before curing tends to be better.

[0045] <(C) Inorganic filler> Because the resin composition for forming a protective film contains (C) an inorganic filler, the film for forming a protective film of this embodiment has excellent shape retention properties, and the protective film formed from the film for forming a protective film of this embodiment has excellent flame retardancy, low thermal expansion, low moisture absorption, etc. The (C) inorganic filler may be used alone or in combination of two or more kinds.

[0046] (C) Examples of inorganic fillers include silica, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, etc. Among these, silica and alumina are preferred, and silica is more preferred. The shape of the (C) inorganic filler is not particularly limited and may be, for example, spherical, crushed, fibrous, etc., but is preferably spherical. The inorganic filler (C) may be surface-modified with a surface treatment agent, etc. As the surface treatment agent, a coupling agent (I) described below can be used.

[0047] (C) Average particle size of inorganic filler (D 50 ) is not particularly limited, but is preferably 0.1 to 10 μm, more preferably 0.2 to 5 μm, and even more preferably 0.3 to 1 μm. (C) Average particle size of inorganic filler (D 50 ) can be determined by measuring the particle size distribution using the Coulter counter method, using a Multisizer Three (manufactured by Beckman Coulter) or similar.

[0048] The content of (C) inorganic filler in the resin composition for forming a protective film is not particularly limited, but is preferably 50% by mass or more, more preferably 53% by mass or more, and even more preferably 55% by mass or more, relative to the solid content (100% by mass) of the resin composition for forming a protective film, and is also preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. When the content of the (C) inorganic filler is equal to or greater than the above lower limit, the shape retention of the film for forming a protective film, the flame retardancy, low thermal expansion, and low moisture absorption of the protective film tend to be better. Also, when the content of the (C) inorganic filler is equal to or less than the above upper limit, the flexibility of the film for forming a protective film before curing tends to be better.

[0049] <(D) Phosphate Compound Derivatives> By including (D) the phosphoric acid compound derivative in the resin composition for forming a protective film, the protective film formed from the film for forming a protective film of this embodiment will have excellent flame retardancy.

[0050] In this embodiment, the term "phosphate compound" refers to a compound having at least a hydroxyl group bonded to a phosphorus atom, and examples of such compounds include organic and inorganic phosphate compounds. Examples of the phosphoric acid compound include phosphoric acid, phosphorous acid, hypophosphorous acid, phosphonic acid, and phosphinic acid. In this specification, the term "phosphonic acid" includes not only inorganic phosphonic acids represented by H3PO3, but also organic phosphonic acids in which one hydrogen atom bonded to the phosphorus atom is substituted with an organic group. Similarly, in this specification, the terms "hypophosphorous acid" and "phosphinic acid" include not only inorganic hypophosphorous acid and inorganic phosphinic acid represented by HPO, but also organic hypophosphorous acid and organic phosphinic acid in which one or two hydrogen atoms bonded to the phosphorus atom are replaced by organic groups. (D) The phosphoric acid compound derivatives may be used alone or in combination of two or more.

[0051] (D) Examples of the phosphoric acid compound derivatives include metal salts and ester compounds of the above phosphoric acid compounds. Specific examples include metal phosphinates, phosphinate ester compounds, metal phosphonates, phosphonate diester compounds, metal phosphates, and phosphate ester compounds. Among these, metal phosphinates and phosphate ester compounds are preferred, and metal phosphinates are more preferred.

[0052] The metal phosphinate is preferably a compound represented by the following general formula (D-1). [ka] (In the formula, R 1 and R 2 each independently represents a substituted or unsubstituted aliphatic hydrocarbon group, or a substituted or unsubstituted aromatic hydrocarbon group. M represents an n-valent metal atom. n represents an integer of 1 to 4.

[0053] R in the above general formula (D-1) 1 and R 2 Examples of the substituted or unsubstituted aliphatic hydrocarbon group represented by the formula (I) include a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, etc. These aliphatic hydrocarbon groups may be either linear or branched. R 1 and R 2 The number of carbon atoms in the substituted or unsubstituted aliphatic hydrocarbon group represented by the formula (I) is not particularly limited, but is preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3. When the aliphatic hydrocarbon group has a substituent, the number of carbon atoms does not include the number of carbon atoms in the substituent. The total number of carbon atoms in all the aliphatic hydrocarbon groups in the general formula (D-1) is not particularly limited, but is preferably 1 to 30, more preferably 3 to 20, and even more preferably 6 to 15. When the aliphatic hydrocarbon group has a substituent, the total number of carbon atoms does not include the number of carbon atoms in the substituent. Examples of the substituent that the aliphatic hydrocarbon group may have include a halogen atom, a hydroxy group, a carboxy group, an alkoxy group, a cyano group, and an aromatic hydrocarbon group. The aromatic hydrocarbon group as a substituent is a group represented by R 1 or R 2 Examples of the aromatic hydrocarbon group include the same as those shown by the formula: As the substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted alkyl group is preferred, a substituted or unsubstituted ethyl group is more preferred, and an unsubstituted ethyl group is even more preferred.

[0054] Examples of the substituted or unsubstituted aromatic hydrocarbon group include a substituted or unsubstituted phenyl group and a substituted or unsubstituted naphthyl group. The number of carbon atoms in the substituted or unsubstituted aromatic hydrocarbon group is not particularly limited, but is preferably 6 to 12, and more preferably 6 to 8. When the aromatic hydrocarbon group has a substituent, the number of carbon atoms does not include the number of carbon atoms in the substituent. Examples of the substituent that the aromatic hydrocarbon group may have include a halogen atom, a hydroxy group, a carboxy group, an alkoxy group, a cyano group, an aliphatic hydrocarbon group, etc. The aliphatic hydrocarbon group as a substituent is the same as the above-mentioned R 1 or R 2 The aliphatic hydrocarbon groups are the same as those shown by the formula (1).

[0055] Examples of the metal represented by M in the general formula (D-1) include lithium, sodium, potassium, calcium, magnesium, aluminum, titanium, zinc, etc. Among these, aluminum is preferred.

[0056] In the above general formula (D-1), n ​​is an integer of 1 to 4, preferably an integer of 2 to 4, and more preferably 3.

[0057] Examples of the phosphoric acid ester compound include aliphatic phosphoric acid ester compounds such as triethyl phosphate; aromatic phosphoric acid ester compounds such as triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, and xylyl diphenyl phosphate; and aromatic condensed phosphoric acid ester compounds such as resorcinol bis(diphenyl)phosphate, resorcinol bis(dicresyl)phosphate, resorcinol bis(di-2,6-xylenyl)phosphate, bisphenol A bis(diphenyl)phosphate, bisphenol A bis(dicresyl)phosphate, bisphenol A bis(di-2,6-xylenyl)phosphate, p-biphenol bis(diphenyl)phosphate, p-biphenol bis(dicresyl)phosphate, and p-biphenol bis(di-2,6-xylenyl)phosphate.

[0058] (D) The phosphoric acid compound derivative may be a solid or a liquid at 23° C., but is preferably a solid from the viewpoint of ease of handling. The solid (D) phosphoric acid compound derivative is preferably in the form of particles.

[0059] (D) When the phosphoric acid compound derivative is in a particulate form, the average particle diameter (D 50 ) is not particularly limited, but is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less. (D) Average particle size of the phosphoric acid compound derivative (D 50 ) can be determined by measuring the particle size distribution using the Coulter counter method, using a Multisizer Three (manufactured by Beckman Coulter) or similar.

[0060] The content of phosphorus atoms in the (D) phosphoric acid compound derivative is not particularly limited, but from the viewpoint of further improving the flame retardancy of the protective film, it is preferably 5 to 40 mass %, more preferably 10 to 30 mass %, and even more preferably 20 to 25 mass %, relative to the (D) phosphoric acid compound derivative (100 mass %).

[0061] In this embodiment, the content of (D) the phosphoric acid compound derivative in the resin composition for forming a protective film is 5.5% by mass or less relative to the solid content (100% by mass) of the resin composition for forming a protective film. By ensuring that the content of (D) the phosphoric acid compound derivative is equal to or less than the upper limit, the film for forming a protective film has excellent flexibility before curing, and the occurrence of curing inhibition is suppressed, making it easier to obtain good curability. The content of (D) the phosphoric acid compound derivative in the resin composition for forming a protective film is preferably 0.5 to 5.3 mass %, more preferably 1 to 4 mass %, and even more preferably 2 to 3 mass %, relative to the solid content (100 mass %) of the resin composition for forming a protective film, from the viewpoints of the flexibility of the film for forming a protective film before curing and the flame retardancy of the protective film.

[0062] <(E) Curing accelerator> The resin composition for forming a protective film may contain (E) a curing accelerator. By including the curing accelerator (E) in the resin composition for forming a protective film, the film for forming a protective film of this embodiment tends to have better curability. The (E) curing accelerator may be used alone or in combination of two or more kinds.

[0063] Examples of the (E) curing accelerator include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole; organic phosphines such as tributylphosphine, diphenylphosphine, and triphenylphosphine; and tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate. Among these, imidazoles are preferred, and 2-phenyl-4,5-dihydroxymethylimidazole is more preferred.

[0064] When the resin composition for forming a protective film contains (E) a curing accelerator, the content of (E) the curing accelerator in the resin composition for forming a protective film is not particularly limited, but is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 1 to 3 parts by mass per 100 parts by mass of the (B) epoxy resin. When the content of the (E) curing accelerator is equal to or greater than the lower limit, the curability of the protective film-forming film tends to be better. When the content of the (E) curing accelerator is equal to or less than the upper limit, the uniformity of the cured product tends to be better.

[0065] <(F) Colorant> The resin composition for forming a protective film may contain (F) a colorant. By including the colorant (F) in the resin composition for forming a protective film, it is possible to impart laser printability, light-blocking properties, design properties, and the like to the protective film formed from the film for forming a protective film of this embodiment. The (F) colorant may be used alone or in combination of two or more kinds.

[0066] (F) Colorants include known ones, such as inorganic pigments, organic pigments, and organic dyes. Examples of inorganic pigments include carbon black, cobalt-based pigments, iron-based pigments, chromium-based pigments, titanium-based pigments, vanadium-based pigments, zirconium-based pigments, molybdenum-based pigments, ruthenium-based pigments, platinum-based pigments, ITO (indium tin oxide)-based pigments, and ATO (antimony tin oxide)-based pigments. Examples of organic pigments and organic dyes include aminium-based dyes, cyanine-based dyes, merocyanine-based dyes, croconium-based dyes, squarium-based dyes, azulenium-based dyes, polymethine-based dyes, naphthoquinone-based dyes, pyrylium-based dyes, phthalocyanine-based dyes, naphthalocyanine-based dyes, naphtholactam-based dyes, azo-based dyes, condensed azo-based dyes, indigo-based dyes, perinone-based dyes, perylene-based dyes, dioxazine-based dyes, quinacridone-based dyes, isoindolinone-based dyes, quinophthalone-based dyes, pyrrole-based dyes, thioindigo-based dyes, metal complex-based dyes (metal complex dyes), dithiol metal complex-based dyes, indolephenol-based dyes, triallylmethane-based dyes, anthraquinone-based dyes, naphthol-based dyes, azomethine-based dyes, benzimidazolone-based dyes, pyranthrone-based dyes, and threne-based dyes.

[0067] When the resin composition for forming a protective film contains a colorant (F), the content of the colorant (F) in the resin composition for forming a protective film is not particularly limited, but from the viewpoint of obtaining an appropriate coloring effect, it is preferably 0.01 to 10 mass %, more preferably 0.05 to 7.5 mass %, even more preferably 0.1 to 5 mass %, and particularly preferably 1 to 3 mass %, relative to the solid content (100 mass %) of the resin composition for forming a protective film.

[0068] <(G) Epoxy resin hardener> The resin composition for forming a protective film may contain (G) an epoxy resin curing agent. By including the epoxy resin curing agent (G) in the resin composition for forming a protective film, the film for forming a protective film of this embodiment tends to have better curability. The (G) epoxy resin curing agent may be used alone or in combination of two or more kinds.

[0069] (G) Epoxy resin curing agents include, for example, compounds having two or more functional groups capable of reacting with epoxy groups in one molecule. Examples of functional groups that can react with an epoxy group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, an anhydride acid group, etc. Among these, a phenolic hydroxyl group, an amino group, and an anhydride acid group are preferred, and a phenolic hydroxyl group and an amino group are more preferred.

[0070] Examples of the (G) epoxy resin curing agent having a phenolic hydroxyl group include phenol-based curing agents such as biphenol, novolac-type phenolic resin, dicyclopentadiene-type phenolic resin, and aralkyl-type phenolic resin. Examples of the (G) epoxy resin curing agent having an amino group include amine-based curing agents such as dicyandiamide.

[0071] Of the (G) epoxy resin curing agent, the molecular weight of the non-resin components such as biphenol and dicyandiamide is not particularly limited, but is preferably 60-500, more preferably 70-200, and even more preferably 80-120.

[0072] When the resin composition for forming a protective film contains an epoxy resin curing agent (G), the content of the epoxy resin curing agent (G) in the resin composition for forming a protective film is not particularly limited, but from the viewpoint of improving the curability of the film for forming a protective film, it is preferably 0.1 to 200 parts by mass, more preferably 0.5 to 100 parts by mass, even more preferably 0.7 to 50 parts by mass, and particularly preferably 1 to 10 parts by mass per 100 parts by mass of the epoxy resin (B).

[0073] <(H) Crosslinking Agent> When the (A) thermoplastic resin has a functional group, the resin composition for forming a protective film may contain (H) a crosslinking agent. By crosslinking the (A) thermoplastic resin having a functional group with the (H) crosslinking agent, the initial adhesive strength and cohesive strength of the film for forming a protective film can be adjusted. The (H) crosslinking agent may be used alone or in combination of two or more kinds.

[0074] Examples of the (H) crosslinking agent include organic polyvalent isocyanate compounds, organic polyvalent imine compounds, metal chelate crosslinking agents (crosslinking agents having a metal chelate structure), and aziridine crosslinking agents (crosslinking agents having an aziridinyl group).

[0075] Examples of organic polyisocyanate compounds include aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, and alicyclic polyisocyanate compounds (hereinafter, these compounds may be collectively referred to as "aromatic polyisocyanate compounds, etc."); trimers, isocyanurates, and adducts of the above aromatic polyisocyanate compounds, etc.; and isocyanate-terminated urethane prepolymers obtained by reacting the above aromatic polyisocyanate compounds, etc. with polyol compounds. The "adduct" refers to a reaction product of the aromatic polyisocyanate compound or the like with a low-molecular-weight active hydrogen-containing compound such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor oil, etc. Specific examples thereof include the tolylene diisocyanate adduct of trimethylolpropane, which will be described later.

[0076] Examples of organic polyisocyanate compounds include 2,4-tolylene diisocyanate; 2,6-tolylene diisocyanate; 1,3-xylylene diisocyanate; 1,4-xylylene diisocyanate; diphenylmethane-4,4'-diisocyanate; diphenylmethane-2,4'-diisocyanate; 3-methyldiphenylmethane diisocyanate; hexamethylene diisocyanate; isophorone diisocyanate; dicyclohexylmethane-4,4'-diisocyanate; dicyclohexylmethane-2,4'-diisocyanate; compounds in which one or more selected from the group consisting of tolylene diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are added to all or some of the hydroxyl groups of a polyol such as trimethylolpropane; lysine diisocyanate, and the like.

[0077] Examples of organic polyvalent imine compounds include N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, and N,N'-toluene-2,4-bis(1-aziridinecarboxamide)triethylenemelamine.

[0078] Among the above options, the crosslinking agent (H) is preferably an organic polyvalent isocyanate compound, more preferably a compound in which one or more species selected from the group consisting of tolylene diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are added to all or some of the hydroxyl groups of a polyol such as trimethylolpropane, and even more preferably a tolylene diisocyanate adduct of trimethylolpropane.

[0079] When an organic polyisocyanate compound is used as the (H) crosslinking agent, the (A) thermoplastic resin preferably has a hydroxy group. When the (H) crosslinking agent has an isocyanate group and the (A) thermoplastic resin has a hydroxy group, a crosslinked structure can be easily introduced into the protective film-forming film by the reaction between the (H) crosslinking agent and the (A) thermoplastic resin.

[0080] When the resin composition for forming a protective film contains a (H) crosslinking agent, the content of the (H) crosslinking agent in the resin composition for forming a protective film is not particularly limited, but from the viewpoint of improving the initial adhesive strength and cohesive strength of the film for forming a protective film, it is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.5 to 5 parts by mass per 100 parts by mass of the (A) thermoplastic resin having a functional group.

[0081] <(I) Coupling Agent> The resin composition for forming a protective film may contain (I) a coupling agent. By including the coupling agent (I) in the resin composition for forming a protective film, the dispersibility of the inorganic filler (C) is improved, and the adhesiveness, water resistance, etc. of the protective film tend to be improved. (I) The coupling agent may be used alone or in combination of two or more kinds.

[0082] (I) Examples of the coupling agent include silane coupling agents, titanate coupling agents, etc. Among these, silane coupling agents are preferred. The (I) coupling agent is preferably one having a functional group capable of reacting with, for example, the (A) thermoplastic resin, (B) epoxy resin, etc., which have a functional group. Examples of the functional group include a glycidyl group, an amino group, a mercapto group, a vinyl group, a (meth)acryloyl group, a hydroxy group, a carboxy group, an imidazole group, etc. Among these, one having a glycidyl group is preferred.

[0083] (I) Examples of coupling agents include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2- Examples of suitable silanes include (aminoethylamino)propylmethyldiethoxysilane, 3-anilinopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane, and partial hydrolysis condensates of one or more of these. Among these, 3-glycidyloxypropyltrimethoxysilane is preferred.

[0084] When the resin composition for forming a protective film contains (I) a coupling agent, the content of (I) the coupling agent in the resin composition for forming a protective film is not particularly limited, but is preferably 0.001 to 10 parts by mass, more preferably 0.005 to 1 part by mass, and even more preferably 0.01 to 0.1 part by mass per 100 parts by mass of the total amount of (A) thermoplastic resin and (B) epoxy resin. When the content of the (I) coupling agent is equal to or greater than the above lower limit, the dispersibility of the (C) inorganic filler, the adhesiveness of the protective film, water resistance, etc. tend to be better. When the content of the (I) coupling agent is equal to or less than the above upper limit, the generation of outgassing tends to be further suppressed.

[0085] <Solvent> The resin composition for forming a protective film may contain a solvent from the viewpoint of facilitating the formation of a film. The solvent may be used alone or in combination of two or more kinds.

[0086] Examples of the solvent include hydrocarbons such as toluene and xylene, alcohols such as methanol, ethanol, 2-propanol, 2-methylpropan-1-ol, and 1-butanol, esters such as ethyl acetate, ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran, and amides (compounds having an amide bond) such as dimethylformamide and N-methylpyrrolidone. Among these, toluene, ethyl acetate, and methyl ethyl ketone are preferred.

[0087] <Other ingredients> The resin composition for forming a protective film may or may not contain components other than the above-mentioned components. Examples of other components include resin components other than the above components, plasticizers, antistatic agents, antioxidants, gettering agents, and flame retardants other than component (D). The other components may each be used alone or in combination of two or more. The content of other components in the resin composition for forming a protective film is not particularly limited and may be appropriately selected depending on the purpose.

[0088] <Method of manufacturing a resin composition for forming a protective film> The resin composition for forming a protective film can be produced by blending the components that constitute the composition. The order of addition when blending the components is not particularly limited, and two or more components may be added simultaneously or sequentially. When a solvent is used, any of the components other than the solvent may be diluted with the solvent before use, or may be mixed with the other components without being diluted with the solvent. The method for mixing the components is not particularly limited, and may be appropriately selected from known methods such as a method of mixing by rotating a stirrer, stirring blades, etc.; a method of mixing using a mixer; or a method of mixing by applying ultrasound. The temperature and time for adding and mixing the components are not particularly limited, and may be adjusted appropriately depending on the components used.

[0089] [Thickness and shape of protective film forming film] The thickness of the film for forming a protective film of the present embodiment is not particularly limited, but is preferably 1 to 100 μm, more preferably 3 to 75 μm, and even more preferably 5 to 50 μm. When the thickness of the protective film-forming film is equal to or greater than the above lower limit, the protective function of the protective film tends to be better. On the other hand, when the thickness of the protective film-forming film is equal to or less than the above upper limit, the protective film tends to be economically advantageous and easy to process, such as by cutting.

[0090] The shape of the film for forming a protective film of this embodiment is not particularly limited, but may be circular in plan view from the viewpoint of being attached to a circular semiconductor wafer. When the shape of the film for forming a protective film is circular in plan view, its diameter is, for example, 200 mm (for an 8-inch wafer), 300 mm (for a 12-inch wafer), etc.

[0091] [Breaking elongation of protective film-forming film] The breaking elongation of the protective film-forming film of this embodiment at a tensile speed of 1,000 mm / min is not particularly limited, but is preferably 50% or more, more preferably 100% or more, even more preferably 130% or more, and particularly preferably 160% or more. When the breaking elongation is within the above range, the film for forming a protective film of the present embodiment tends to be less prone to tearing during processing performed before being attached to an object to be protected. The upper limit of the breaking elongation of the protective film-forming film of this embodiment at a tensile speed of 1,000 mm / min is not particularly limited, but may be 1,500% or less, 1,000% or less, or 500% or less. The breaking elongation of the film for forming a protective film at a tensile speed of 1,000 mm / min can be measured by the method described in the examples.

[0092] [Method of using the protective film] The protective film-forming film of this embodiment can be attached to the object to be protected by pressing it against the object to be protected. When pressing, the protective film-forming film may be heated as necessary.

[0093] Examples of objects to be protected to which the protective film forming film of this embodiment is attached include semiconductor wafers, semiconductor chips, etc. When the protective film forming film is attached to a semiconductor wafer, for example, the protective film forming film is attached to the back surface of the semiconductor wafer and thermally cured to form a semiconductor wafer with a protective film, and then the semiconductor wafer with a protective film is singulated to obtain semiconductor chips with a protective film on the back surface. Examples of semiconductor wafers include silicon wafers; wafers of gallium arsenide, silicon carbide, sapphire, lithium tantalate, lithium niobate, gallium nitride, indium phosphide, and the like; and glass wafers. The semiconductor chips include those obtained by cutting the semiconductor wafer into individual pieces.

[0094] The semiconductor wafer or semiconductor chip to which the protective film forming film of this embodiment is attached is preferably one that has undergone back grinding. The thickness of the semiconductor wafer or semiconductor chip after back grinding is not particularly limited, but is preferably 5 to 150 μm, more preferably 7 to 100 μm, and even more preferably 10 to 45 μm.

[0095] The curing conditions after the protective film-forming film is attached to the object to be protected are not particularly limited and may be determined appropriately depending on the type of protective film-forming film. For example, the heating temperature when thermally curing the protective film-forming film may be 100 to 200°C, 110 to 180°C, or 120 to 170°C. The heating time when thermally curing the protective film-forming film may be 0.5 to 5 hours, 0.7 to 4 hours, or 1 to 3 hours.

[0096] The timing of attaching the film for forming a protective film of this embodiment to the object to be protected and the timing of thermal curing are not particularly limited, and may be determined appropriately depending on the process in which the film for forming a protective film of this embodiment is used. For example, in a process for manufacturing semiconductor chips by grinding the backside of a semiconductor wafer and then dicing it, a protective film forming film can be attached to the semiconductor wafer or semiconductor chip and thermally cured to form a protective film at any time between after grinding the backside of the semiconductor wafer and before mounting the diced semiconductor chips on a substrate. However, from the viewpoint of suppressing breakage and the like when the semiconductor wafer is diced, it is preferable to form a semiconductor wafer with a protective film by attaching a protective film-forming film to the back surface of the semiconductor wafer after grinding the back surface of the semiconductor wafer and thermally curing it before dicing. As a method for dividing the semiconductor wafer with the protective film, for example, a known dividing method such as a blade dicing method, a laser dicing method, or a Stealth Dicing (registered trademark) method can be applied. The semiconductor wafer with the protective film is divided into individual pieces to obtain semiconductor chips with the protective film.

[0097] [Method for producing a film for forming a protective film] The film for forming a protective film can be produced, for example, by forming a resin composition for forming a protective film into a film shape. Specifically, for example, the resin composition for forming a protective film can be applied to a support sheet such as a release film and dried as necessary to form the film for forming a protective film on the support sheet.

[0098] [First embodiment of composite sheet for forming protective film] The composite sheet for forming a protective film according to the first aspect of this embodiment has a configuration in which the film for forming a protective film according to this embodiment is sandwiched between two release films. In this specification, "peeling film" means a film that has the ability to be peeled off, and is attached to the surface of a film for forming a protective film in order to protect the film for forming a protective film before it is attached to an object to be protected. The preferred embodiment of the film for forming a protective film included in the composite sheet for forming a protective film of the first embodiment is as described above.

[0099] <Configuration of the first embodiment of the composite sheet for forming a protective film> 1 is a cross-sectional view schematically illustrating an example of a composite sheet for forming a protective film according to the first embodiment. Note that, for convenience, the drawings used in the following description may show enlarged essential parts, and the dimensional ratios of the components may not necessarily be the same as those in the actual cases.

[0100] The composite sheet 1 for forming a protective film shown in FIG. 1 has a first release film 111 on one surface 10a of a film 10 for forming a protective film, and a second release film 112 on the other surface 10b. The composite sheet for forming a protective film having such a configuration is suitable for storage, for example, in a roll form. The first release film 111 and the second release film 112 may be the same as or different from each other. For example, the first release film 111 and the second release film 112 may be different in the peeling force required to peel them from the protective film-forming film 10.

[0101] <Release film> An example of a release film that can be used in the composite sheet for forming a protective film is one in which a release agent is applied to a substrate for the release film. Examples of substrates for release films include transparent films such as polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, ionomer resin film, ethylene-(meth)acrylic acid copolymer film, ethylene-(meth)acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, and fluororesin film; crosslinked films thereof; colored films thereof; opaque films; and papers such as fine paper, glassine paper, and kraft paper. These may be used as a single layer or as a laminate of two or more layers.

[0102] Examples of the release agent include rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins; long-chain alkyl resins, alkyd resins, and fluorine-containing resins. One type of release agent may be used alone, or two or more types may be used in combination.

[0103] The thickness of the release film is not particularly limited, but is preferably 10 to 500 μm, more preferably 15 to 300 μm, and even more preferably 20 to 100 μm. When the thickness of the release film is equal to or greater than the lower limit, the composite sheet for forming a protective film tends to have better deformation resistance, whereas when the thickness of the release film is equal to or less than the upper limit, the composite sheet for forming a protective film tends to have appropriate flexibility and be easier to handle.

[0104] <Method for producing the composite sheet for forming a protective film according to the first embodiment> The composite sheet for forming a protective film of the first embodiment can be produced in accordance with the above-mentioned [Method for producing a film for forming a protective film]. Specifically, for example, the target to which the resin composition for forming a protective film is applied is the release-treated surface of a release film, a film for forming a protective film is formed on the release film, and then the release-treated surface of another release film is attached to the exposed surface of the film for forming a protective film, thereby producing the composite sheet for forming a protective film of the first embodiment.

[0105] [Second embodiment of composite sheet for forming protective film] The composite sheet for forming a protective film according to the second aspect of this embodiment is a composite sheet for forming a protective film that includes a substrate, a pressure-sensitive adhesive layer, and the film for forming a protective film according to this embodiment in this order. The preferred embodiment of the film for forming a protective film that the composite sheet for forming a protective film of the second embodiment has is as described above.

[0106] The composite sheet for forming a protective film of the second embodiment has a substrate and a pressure-sensitive adhesive layer in addition to a film for forming a protective film. Therefore, for example, when the film for forming a protective film of the composite sheet for forming a protective film of the second embodiment is attached to a semiconductor wafer and thermally cured to form a protective film, a semiconductor wafer with a protective film supported by the substrate via the pressure-sensitive adhesive layer is obtained. The semiconductor wafer with a protective film supported by the substrate via the pressure-sensitive adhesive layer can be divided into individual pieces, for example, by fixing the surface on the substrate side. In other words, the composite sheet for forming a protective film of the second embodiment can be used as a dicing sheet in which the film for forming a protective film and a substrate and a pressure-sensitive adhesive layer are integrated.

[0107] <Configuration of the second embodiment of the composite sheet for forming a protective film> The composite sheet for forming a protective film of the second embodiment may consist of only a substrate, a pressure-sensitive adhesive layer, and a film for forming a protective film, or may have other components in addition to the substrate, the pressure-sensitive adhesive layer, and the film for forming a protective film. Examples of other components include a release film laminated on the surface of the film for forming a protective film opposite to the pressure-sensitive adhesive layer. The preferred embodiments of the release film that the composite sheet for forming a protective film of the second embodiment may have are as described above.

[0108] 2 and 3 are cross-sectional views schematically showing examples of the composite sheet for forming a protective film according to the second embodiment. In each figure, the same components as those shown in figures that have already been described are given the same reference numerals as in the figures that have already been described, and detailed description thereof will be omitted.

[0109] The composite sheet 1A for forming a protective film shown in Fig. 2 has an adhesive layer 13 on a substrate 12, and has a film 10 for forming a protective film on the adhesive layer 13. The composite sheet 1A for forming a protective film further has a release film 11 laminated on a surface 10a (upper surface) of the film 10 for forming a protective film and a surface 13a (upper surface) of the adhesive layer 13. With the release film 11 removed, the composite sheet 1A for forming a protective film is used with the back surface of a semiconductor wafer (not shown) attached to a central region of the surface 10a of the film 10 for forming a protective film, and further with an area near the periphery of the film 10 for forming a protective film attached to a jig such as a ring frame.

[0110] The composite sheet 1B for forming a protective film shown in Figure 3 is the same as the composite sheet 1A for forming a protective film shown in Figure 2, except that a jig adhesive layer 14 is laminated on a portion of the surface 13a of the pressure-sensitive adhesive layer 13, i.e., the area near the peripheral portion, and a release film 11 is laminated on the surface 10a (top surface) of the film 10 for forming a protective film and the surface 14a (top surface) of the jig adhesive layer 14. The jig adhesive layer 14 may be, for example, a single-layer structure containing an adhesive component, or a multi-layer structure in which layers containing adhesive components are laminated on both sides of a core sheet. The composite sheet 1B for forming a protective film is used by removing the release film 11, attaching the back surface of a semiconductor wafer (not shown) to the surface 10a of the film 10 for forming a protective film, and further attaching the upper surface of the surface 14a of the jig adhesive layer 14 to a jig such as a ring frame.

[0111] The composite sheet for forming a protective film of the second aspect of this embodiment is not limited to that shown in Figures 2 and 3, and may have some of the configurations shown in Figures 2 and 3 changed or deleted, or may have other configurations added to those described so far, within the scope that does not impair the effects of this embodiment.

[0112] <Base material> Examples of materials that can be used for the substrate include various resins. Examples of resins constituting the substrate include polyethylenes such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE); polyolefins other than polyethylene such as polypropylene, polybutene, polybutadiene, polymethylpentene, and norbornene resin; ethylene-based copolymers (copolymers obtained using ethylene as a monomer) such as ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, and ethylene-norbornene copolymer; vinyl chloride-based resins (resins obtained using vinyl chloride as a monomer) such as polyvinyl chloride and vinyl chloride copolymer; polystyrene; polycycloolefins; Examples of the resin include polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene isophthalate, polyethylene-2,6-naphthalenedicarboxylate, and wholly aromatic polyesters in which all structural units have aromatic cyclic groups; copolymers of two or more polyesters; poly(meth)acrylic acid esters; polyurethanes; polyurethane acrylates; polyimides; polyamides; polycarbonates; fluororesins; polyacetals; modified polyphenylene oxides; polyphenylene sulfides; polysulfones; polyether ketones; crosslinked resins in which one or more of these resins are crosslinked; and modified resins such as ionomers using one or more of these resins. The resin constituting the substrate may be used alone or in combination of two or more. Among these, polypropylene and polybutylene terephthalate are preferred from the viewpoint of heat resistance.

[0113] In addition to the resins described above, the substrate may contain various known additives such as fillers, colorants, antistatic agents, antioxidants, organic lubricants, catalysts, and softeners (plasticizers).

[0114] The substrate may be surface-treated to improve adhesion to other layers such as a pressure-sensitive adhesive layer. Examples of surface treatment methods include roughening treatments such as sandblasting and solvent treatment, oxidation treatments such as corona discharge treatment, electron beam irradiation treatment, plasma treatment, ozone / ultraviolet irradiation treatment, flame treatment, chromic acid treatment and hot air treatment, primer treatment, etc. Among these, those that have been subjected to electron beam irradiation treatment are preferred from the viewpoint of suppressing the generation of base fragments due to blade friction when the composite sheet for forming a protective film is used in blade dicing.

[0115] The substrate may consist of only one layer, or may consist of two or more layers. When the substrate consists of multiple layers, the layers constituting the multiple layers may be the same as or different from each other. Furthermore, the substrate may have, for example, an antistatic coating layer, a layer for preventing the substrate from adhering to other sheets or the substrate from adhering to an adsorption table when the composite sheet for forming a protective film is stacked and stored, or the like.

[0116] The thickness of the substrate is not particularly limited, but is preferably 40 to 300 μm, more preferably 50 to 200 μm, and even more preferably 60 to 150 μm. When the thickness of the substrate is within the above range, the flexibility and application properties of the composite sheet for forming a protective film tend to be better.

[0117] <Adhesive layer> The pressure-sensitive adhesive layer is a layer having adhesiveness and provided between the substrate and the film for forming a protective film. The pressure-sensitive adhesive layer may consist of only one layer, or may consist of two or more layers. When the pressure-sensitive adhesive layer consists of multiple layers, the layers constituting the multiple layers may be the same as or different from each other.

[0118] Examples of adhesive resins constituting the adhesive layer include acrylic resins, urethane resins, rubber-based resins, silicone resins, epoxy resins, polyvinyl ether resins, polycarbonate resins, ester-based resins, etc. When these adhesive resins are copolymers having two or more types of structural units, the form of the copolymer is not particularly limited and may be any of a block copolymer, a random copolymer, and a graft copolymer. Among these, acrylic resins are preferred from the viewpoint of exhibiting excellent adhesive strength.

[0119] In this embodiment, the term "adhesive resin" is a concept that includes both resins that have adhesive properties and resins that have adhesive properties, and includes, for example, not only resins that are adhesive in themselves, but also resins that become adhesive when used in combination with other components such as additives; resins that become adhesive in the presence of a trigger such as heat or water; etc.

[0120] The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 3 to 30 μm, more preferably 4 to 20 μm, and even more preferably 5 to 17 μm. When the thickness of the pressure-sensitive adhesive layer is equal to or greater than the lower limit, the tack and adhesive strength tend to be better. When the thickness of the pressure-sensitive adhesive layer is equal to or less than the upper limit, the blade dicing suitability and pick-up suitability tend to be better when the composite sheet for forming a protective film is used in blade dicing.

[0121] The pressure-sensitive adhesive layer may be formed using an energy ray-curable pressure-sensitive adhesive or a non-energy ray-curable pressure-sensitive adhesive. The non-energy ray-curable pressure-sensitive adhesive includes a thermosetting pressure-sensitive adhesive and a non-curable pressure-sensitive adhesive.

[0122] <Method for producing the composite sheet for forming a protective film according to the second embodiment> The composite sheet for forming a protective film of the second embodiment can be produced by sequentially laminating the layers constituting the composite sheet for forming a protective film in a corresponding positional relationship. Each layer can be formed in accordance with the above-mentioned [Method for producing a film for forming a protective film]. Specifically, for example, a resin composition for forming a protective film may be applied to the surface of an adhesive layer laminated on a substrate to form a film for forming a protective film on the adhesive layer, or a film for forming a protective film may be formed in advance on the release-treated surface of a release film, and the exposed surface of the film for forming a protective film may be attached to the surface of the adhesive layer laminated on the substrate to laminate the film for forming a protective film on the adhesive layer. Similarly, when a pressure-sensitive adhesive layer is laminated on a substrate, a composition for forming the pressure-sensitive adhesive layer may be applied to the surface of the substrate, or the exposed surface of the pressure-sensitive adhesive layer formed on the release-treated surface of a release film may be attached to the surface of the substrate, and then the release film may be removed. When the composite sheet for forming a protective film of the second embodiment has an optional layer such as an intermediate layer, the optional layer may be provided at a required position in accordance with the above method.

[0123] [Semiconductor chip with protective film] The semiconductor chip with a protective film of this embodiment is a semiconductor chip with a protective film that has a protective film that is a cured product of the film for forming a protective film of this embodiment. The preferred embodiments of the protective film-forming film used to form the protective film of the semiconductor chip with a protective film of this embodiment, the protective film formed from the protective film-forming film, and the semiconductor chip have been described above. The size of the semiconductor chip in plan view is not particularly limited, but is preferably 600 mm 2 Less than 400mm, preferably 2 Less than 300 mm, more preferably 2 The plan view refers to a view in the thickness direction. The shape of the semiconductor chip in plan view may be square or may be an elongated shape such as a rectangle. The semiconductor chip with a protective film of this embodiment can be manufactured by the method explained in the method of using the film for forming a protective film of this embodiment.

[0124] [Semiconductor Devices] The semiconductor device of this embodiment is a semiconductor device having the semiconductor chip with the protective film of this embodiment. An example of the semiconductor device of this embodiment is a semiconductor package in which the semiconductor chip with the protective film of this embodiment is flip-chip connected to a substrate having a circuit. [Example]

[0125] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The physical properties in each example were measured by the following methods.

[0126] [Mass average molecular weight (Mw)] Measurement was carried out using a gel permeation chromatograph (manufactured by Tosoh Corporation, product name "HLC-8020") under the conditions below, and the values ​​measured were converted into standard polystyrene equivalents. (Measurement conditions) Column: "TSK guard column SuperH-H", "TSK gel SuperHM-H", "TSK gel SuperHM-H", "TSK gel SuperH2000" (all manufactured by Tosoh Corporation) connected in series Column temperature: 40℃ Developing solvent: tetrahydrofuran ·Flow rate: 1.0mL / min

[0127] [Thickness of each layer] Using a constant pressure thickness gauge manufactured by Teclock Corporation (model number: "PG-02J", standard specifications: JIS K6783, Z1702, Z1709), the thickness was measured at any five points at 23°C, and the average of the measured values ​​was calculated.

[0128] [Manufacturing of protective film] Examples 1 to 4, Comparative Examples 1 to 4 (Production of Resin Composition) Each component shown in Table 1 was dissolved or dispersed in a mixed solvent of methyl ethyl ketone, toluene, and ethyl acetate according to the formulation shown in Table 1, and then the mixture was stirred at 23°C to obtain a resin composition with a solid content of 62% by mass.

[0129] (Preparation of protective film) The resin composition obtained above was applied using a knife coater to the release-treated surface of release film 1 (manufactured by Lintec Corporation, product name "SP-PET502150", a 50 μm-thick polyethylene terephthalate film with one side release-treated with a silicone resin), and dried at 100°C for 2 minutes to form a 25 μm-thick protective film-forming film on release film 1. The release-treated surface of release film 2 (manufactured by Lintec Corporation, product name "SP-PET381130", a 38 μm-thick polyethylene terephthalate film with one side release-treated with a silicone resin) was then attached to the protective film-forming film, producing a protective film-forming film sandwiched between two release films (hereinafter also referred to as "protective film-forming film with double-sided release films").

[0130] [Evaluation method] The protective film-forming films obtained in each example were evaluated by the methods shown below.

[0131] (Flame retardancy evaluation method) Two sheets of the protective film-forming film with double-sided release film obtained in each example were prepared by removing release film 2. The exposed protective film-forming film surfaces were directly laminated together while being pressed with a roll laminator heated to 70°C to produce a protective film-forming film approximately 50 μm thick. Release film 1 was then removed from one side. The exposed protective film-forming film was attached to a silicon wafer piece (a 100 μm-thick silicon wafer with a #2,000 polished surface cut into a rectangular shape 125 mm long and 13 mm wide). Release film 1 was then removed, and the protective film-forming film attached to the silicon wafer piece was cured by heating at 180°C for 2 hours in an air atmosphere to form a protective film. Next, unnecessary portions of the protective film were cut and removed to the same shape as the silicon wafer piece, and the resulting silicon wafer piece with the protective film was used as a test piece for flame retardancy testing. Five test pieces were prepared for each example. The obtained test specimens were conditioned for 48 hours in a temperature-controlled room at 23°C and 50% humidity, and then a flame retardancy test was conducted in accordance with the UL94V test (vertical flame test) of the UL94 test (flammability test for plastic materials for equipment components) established by Underwriters Laboratories (UL) in the United States. In addition, after conducting a flame contact test on five test specimens included in the UL94V test, the length of the unburned residue for each test specimen was measured, and the average length of the unburned residue for the five test specimens was calculated. The grades in the UL94V test and the average unburned length of the test specimens are shown in Table 1. Note that "NOT" in Table 1 means that the V-2 standard in the UL94V test was not met.

[0132] (Method for measuring breaking elongation) One sheet of the protective film-forming film with double-sided release film obtained in each example was prepared by removing release film 2, folding it in half with the exposed protective film-forming film surface facing inward, and pressing it with a roll laminator heated to 70°C to directly laminate the protective film-forming films together. Next, one release film 1 was removed, and the film was folded in half again with the exposed protective film-forming film surface facing inward, and pressed under the same conditions as above. The same procedure was repeated to produce a protective film-forming film with double-sided release films having a thickness of approximately 200 μm. The protective film-forming film with double-sided release films was cut to a size of 60 mm in length and 15 mm in width, and the release films on both sides were removed to prepare a test piece for measuring breaking elongation. The test pieces obtained above were subjected to a tensile test using a tensile testing machine (Shimadzu Corporation, product name "Autograph AG-IS1kN") under conditions of 23°C, relative humidity of 50%, tensile speed of 1,000 mm / min, and chuck distance of 10 mm, to measure the breaking elongation. The breaking elongation is calculated by the following formula. Breaking elongation (%) = {(L-L0) / L0} × 100 L = length of specimen at break L0 = length of specimen before test

[0133] [Table 1]

[0134] The details of each component shown in Table 1 are as follows: <(A) Thermoplastic resin> Acrylic resin obtained by copolymerizing 85 parts by mass of methyl acrylate and 15 parts by mass of 2-hydroxyethyl acrylate (mass average molecular weight (Mw): 370,000, glass transition temperature: 6°C)

[0135] <(B) Epoxy resin> (B)-1: Dicyclopentadiene-type epoxy resin (manufactured by DIC Corporation, product name "Epiclon HP-7200HH", epoxy equivalent 255 to 260 g / eq) (B)-2: Bisphenol A epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "jER1055", epoxy equivalent 800 to 900 g / eq) (B)-3: Bisphenol A epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "jER828", epoxy equivalent 184 to 194 g / eq)

[0136] <(C) Inorganic filler> Spherical silica (manufactured by Admatechs Co., Ltd., product name "SC2050MA"), average particle diameter (D 50 )0.5μm)

[0137] <(D) Phosphate Compound Derivatives> (D)-1: Aluminum trisdiethylphosphinate (manufactured by Clariant Chemicals, product name "EXOLIT OP935"), average particle size (D 50 )2~3μm) (D)-2: Aluminum trisdiethylphosphinate (manufactured by Clariant Chemicals, product name "EXOLIT OP945"), average particle size (D 50 )2μm or less)

[0138] <(E) Curing accelerator> 2-phenyl-4,5-dihydroxymethylimidazole

[0139] <(F) Colorant> Carbon black (manufactured by Mitsubishi Chemical Corporation, product name "MA600")

[0140] <(G) Epoxy resin hardener> Dicyandiamide-type latent hardener (ADEKA Corporation, product name "ADEKA Hardener EH-3636AS", active hydrogen equivalent 21g / eq)

[0141] <(H) Crosslinking Agent> Tolylene diisocyanate adduct of trimethylolpropane

[0142] <(I) Coupling Agent> 3-Glycidyloxypropyltrimethoxysilane

[0143] It can be seen from Table 1 that the films for forming a protective film of Examples 1 to 4 of this embodiment had excellent flexibility before curing and the flame retardancy of the protective film was also excellent. On the other hand, the protective film formed from the film for forming a protective film of Comparative Example 1, which did not contain the (D) phosphoric acid compound derivative, had poor flame retardancy, and the films for forming a protective film of Comparative Examples 2 to 4, which had a content of the (D) phosphoric acid compound derivative exceeding 5.5 mass%, had poor flexibility before curing. [Explanation of symbols]

[0144] 1, 1A, 1B Composite sheet for forming protective film 10 Protective film forming film 10a, 10b Surface of the release film side of the protective film forming film 11 release film, 111 First release film 112 Second release film 12 Base material 13 Adhesive layer 13a Surface of the adhesive layer on the protective film forming film side 14 Adhesive layer for jig 14a Surface of the jig adhesive layer on the release film side

Claims

1. (A) a thermoplastic resin, (B) an epoxy resin, (C) an inorganic filler, and (D) a phosphoric acid compound derivative; A film for forming a protective film formed using a resin composition containing the content of phosphorus atoms in the resin composition is 0.3% by mass or more relative to the solid content (100% by mass) of the resin composition; The film for forming a protective film, wherein the content of the (D) phosphoric acid compound derivative in the resin composition is 5.5 mass % or less relative to the solid content (100 mass %) of the resin composition.

2. The film for forming a protective film according to claim 1 , wherein the (D) phosphoric acid compound derivative is a metal phosphinate.

3. The film for forming a protective film according to claim 2, wherein the metal phosphinate is represented by the following general formula (D-1): 【Chemistry 1】 (In the formula, R １ and R ２ each independently represents a substituted or unsubstituted aliphatic hydrocarbon group or a substituted or unsubstituted aromatic hydrocarbon group; M represents an n-valent metal atom; and n represents an integer of 1 to 4.

4. The film for forming a protective film according to any one of claims 1 to 3, wherein the thermoplastic resin (A) is an acrylic resin.

5. The content of the inorganic filler (C) in the resin composition is 50% by mass or more relative to the solid content (100% by mass) of the resin composition. The film for forming a protective film according to any one of claims 1 to 4.

6. The film for forming a protective film according to any one of claims 1 to 5, wherein the resin composition further contains (E) a curing accelerator.

7. The film for forming a protective film according to any one of claims 1 to 6, wherein the resin composition further contains (F) a colorant.

8. The film for forming a protective film according to any one of claims 1 to 7, which is attached to the back surface of a semiconductor wafer and used in the manufacture of a semiconductor chip with a protective film.

9. A composite sheet for forming a protective film, comprising the film for forming a protective film according to any one of claims 1 to 8 sandwiched between two release sheets.

10. A composite sheet for forming a protective film, comprising a substrate, a pressure-sensitive adhesive layer, and the film for forming a protective film according to any one of claims 1 to 8, in this order.

11. A semiconductor chip with a protective film, comprising a protective film which is a cured product of the film for forming a protective film according to any one of claims 1 to 8.

12. A semiconductor device comprising the semiconductor chip with a protective film according to claim 11.

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