JP2023141696A - Protective film-forming film, protective film-forming composite sheet, protective film-equipped semiconductor chip, and semiconductor device - Google Patents

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 nitrogen atom-containing compound containing no phosphorus atom. The content of the nitrogen atom-containing compound (D) containing no phosphorus atom in the resin composition is 5.5-10 mass% 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

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.

2. Description of the Related Art In recent years, semiconductor devices have been manufactured using a mounting method called a so-called face down method, in which a semiconductor chip is mounted on a substrate with the circuit surface facing the substrate side.
In the face-down method, electrodes such as bumps formed on the circuit surface of the semiconductor chip are bonded to the substrate, so the back surface of the semiconductor chip is A protective film may be formed on the surface.
The protective film plays a role in protecting the semiconductor chip from external impacts during the manufacturing process of the semiconductor chip and after the semiconductor chip is mounted. Further, the protective film can be used for identification, decoration, etc. of semiconductor chips by laser printing. Furthermore, the protective film can also function as a light-shielding layer that prevents malfunction of the circuit.

The protective film is formed using, for example, a film for forming a protective film. As the film for forming a protective film, from the viewpoint of mechanical strength, heat resistance, etc., a curable film made of a thermosetting or energy ray curable resin composition is used. A 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 having a pencil hardness of 5H or more after curing.

Japanese Patent Application Publication No. 2009-147277

Before the film for forming a protective film is attached to the object to be protected, it is usually punched out in the same shape as the object to be protected, and then the release film that protects the surface is peeled off and then the film is attached to the object to be protected. affixed to the surface. The film for forming a protective film before curing is required to have flexibility so that the film for forming a protective film will not be torn by the mechanical force applied in each of these steps.

Incidentally, in recent years, the level of flame retardancy required for electronic components has been increasing from the viewpoint of improving safety. Halogen-based flame retardants have traditionally been used as flame retardants to improve the flame retardant properties of plastic products, but halogen-based flame retardants are suspected of emitting toxic substances when incinerated, so their use has been discouraged. The movement is progressing.
However, according to the studies conducted by the present inventors, if a flame retardant substitute for halogen-based flame retardants is used to make a film for forming a protective film flame retardant, the flexibility required for a film for forming a protective film before curing will be reduced. It was confirmed that the problem of insufficient quality occurred. Therefore, in a film for forming a protective film, it has been difficult to achieve both flexibility before curing and flame retardancy of the formed protective film.

The present invention has been made in view of the above-mentioned problems, and includes a protective film-forming film that can form a protective film with excellent flame retardancy and excellent flexibility before curing, and a protective film-forming film that uses the protective film-forming film. The present invention aims to provide a composite sheet for forming a protective film, a semiconductor chip with a protective film, and a semiconductor device.

The present inventors have found that the above problems can be solved by using a resin composition containing a thermoplastic resin, an epoxy resin, an inorganic filler, and a nitrogen atom-containing compound that does not contain a phosphorus atom. This discovery led to the completion of the present invention.

That is, the present invention relates to the following [1] to [14].
[1] Formed using a resin composition containing (A) a thermoplastic resin, (B) an epoxy resin, (C) an inorganic filler, and (D) a nitrogen atom-containing compound that does not contain a phosphorus atom. A film for forming a protective film, comprising:
The content of the nitrogen atom-containing compound (D) that does not contain a phosphorus atom in the resin composition is 5.5 to 10% by mass with respect to the solid content (100% by mass) of the resin composition. Film for forming a protective film.
[2] The film for forming a protective film according to [1] above, wherein the nitrogen atom-containing compound (D) that does not contain a phosphorus atom is a nitrogen atom-containing heterocyclic compound.
[3] The film for forming a protective film according to [2] above, wherein the nitrogen atom-containing heterocyclic compound is a compound having a triazine ring.
[4] The film for forming a protective film according to [3] above, wherein the compound having a triazine ring is melamine cyanurate.
[5] The film for forming a protective film according to any one of [1] to [4] above, wherein the thermoplastic resin (A) is an acrylic resin.
[6] The content of the inorganic filler (C) in the resin composition is 50% by mass or more based on the solid content (100% by mass) of the resin composition, [1] to [5] above. ] The film for forming a protective film according to any one of the above.
[7] The film for forming a protective film according to any one of [1] to [6] above, wherein the resin composition further contains (E) a curing accelerator.
[8] The film for forming a protective film according to any one of [1] to [7] above, wherein the resin composition further contains (F) a colorant.
[9] The film for forming a protective film according to any one of [1] to [8] above, which has a breaking elongation of 50% or more at a tensile speed of 1,000 mm/min.
[10] The film for forming a protective film according to any one of [1] to [9] above, which is attached to the back surface of a semiconductor wafer and used for manufacturing a semiconductor chip with a protective film.
[11] A composite sheet for forming a protective film, which has a structure in which the film for forming a protective film according to any one of [1] to [10] above is sandwiched between two release sheets.
[12] A composite sheet for forming a protective film, comprising a base material, an adhesive layer, and the film for forming a protective film according to any one of [1] to [10] above, in this order.
[13] A semiconductor chip with a protective film, comprising a protective film that is a cured product of the film for forming a protective film according to any one of [1] to [10] above.
[14] A semiconductor device comprising the protective film-equipped semiconductor chip according to [13] above.

According to the present invention, a protective film-forming film capable of forming a protective film with excellent flame retardancy and excellent flexibility before curing, a protective film-forming composite sheet using the protective film-forming film, and a semiconductor chip with a protective film and a semiconductor device can be provided.

FIG. 1 is a schematic cross-sectional view showing an example of the structure of a composite sheet for forming a protective film according to the first embodiment of the present invention. It is a typical sectional view showing an example of composition of a composite sheet for protective film formation of a second aspect of the present invention. It is a typical sectional view showing another example of composition of a composite sheet for protective film formation of a second aspect of the present invention.

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, as described in Examples. This is the value measured based on the method.

In this specification, the lower and upper limits described in stages for preferred numerical ranges (for example, ranges of content, etc.) can be independently combined. For example, from the description "preferably 10 to 90, more preferably 30 to 60", the "preferable lower limit (10)" and "more preferable upper limit (60)" are combined to become "10 to 60". You can also do that.

As used herein, the term "energy ray" refers to electromagnetic waves or charged particle beams that have energy quanta. Examples of energy rays include ultraviolet rays, radiation, electron beams, and the like. 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. The electron beam can be generated by an electron beam accelerator or the like.

In addition, in this specification, "energy ray curable" means a property that hardens by irradiation with energy rays, and "non-energy ray curable" means a property that does not harden even when irradiated with energy rays. and includes thermosetting and non-curing properties. "Thermosetting" means a property of being hardened by heating, and "non-curing" means a property of not being hardened by heating or irradiation with energy rays.

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

In this specification, the "circuit surface" of a semiconductor wafer and a semiconductor chip refers to the surface on which a circuit is formed, and the "back surface" of a semiconductor wafer and a semiconductor chip refers to the surface opposite to the circuit surface.

In this specification, the "thickness" of a certain object means the thickness of the whole object; for example, when the object consists of multiple layers, the total thickness of all the layers constituting the object. means the thickness of The "object" herein means a protective film-forming film, a release film, a base material, an adhesive layer, etc., which will be described later.
The thickness herein is a value measured based on the method described in Examples.

As used herein, "solid content" refers to the components contained in the target composition excluding diluent solvents such as water and organic solvents.

The mechanism of action described herein is speculative and does not limit the mechanism by which the effects of the present invention are achieved.

[Film for forming protective film]
The film for forming a protective film of this embodiment is
Protection formed using a resin composition containing (A) a thermoplastic resin, (B) an epoxy resin, (C) an inorganic filler, and (D) a nitrogen atom-containing compound that does not contain a phosphorus atom. A film for film formation,
The content of the nitrogen atom-containing compound (D) that does not contain a phosphorus atom in the resin composition is 5.5 to 10% by mass with respect to the solid content (100% by mass) of the resin composition. This is a film for forming a protective film.

The film for forming a protective film of this embodiment has at least thermosetting properties. Here, in this specification, the term "film for forming a protective film" means a film before curing, and the term "protective film" means a 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 thermally cured, thereby becoming a protective film that protects the object to be protected from external impacts and the like. In particular, the film for forming a protective film of this embodiment is applied to the back surface of a semiconductor wafer and is useful for manufacturing a semiconductor chip with a protective film.
Since the protective film formed from the film for forming a protective film of this embodiment has excellent flame retardancy, the object to be protected with the protective film formed from the film for forming a protective film of this embodiment is safe. Excellent in sex.
Moreover, since the film for forming a protective film of this embodiment has excellent flexibility before curing, the occurrence of tearing and the like when punching into the same shape as the object to be protected is suppressed.

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 is composed of multiple layers, the layers constituting the multiple layers may be the same or different from each other.

In addition, in the following description, the resin composition used for forming the film for forming a protective film of this embodiment may be called a "resin composition for forming a protective film."

[Resin composition for forming a protective film]
The resin composition for forming a protective film is a resin containing (A) a thermoplastic resin, (B) an epoxy resin, (C) an inorganic filler, and (D) a nitrogen atom-containing compound that does not contain a phosphorus atom. It is a composition.

Hereinafter, each component contained in the resin composition for forming a protective film will be explained in detail.

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

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

It is preferable that the raw material monomer of the acrylic resin 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.

(Meth)acrylic acid esters include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, ) 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 ) acrylate, alkyl (meth)acrylates such as pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate; cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl Cycloalkyl (meth)acrylates such as (meth)acrylate; Aralkyl (meth)acrylates such as benzyl (meth)acrylate; Cycloalkenyl (meth)acrylates such as dicyclopentenyl (meth)acrylate; Dicyclopentenyloxyethyl (meth) Cycloalkenyloxyalkyl (meth)acrylate such as acrylate; Imide (meth)acrylate; Glycidyl group-containing (meth)acrylate such as glycidyl (meth)acrylate; Hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2 - Hydroxy group-containing (meth)acrylate such as hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc. ) acrylates; substituted amino group-containing (meth)acrylates such as N-methylaminoethyl (meth)acrylate; and the like.

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 to 18, more preferably 1 to 10, and still more preferably 1 to 4.
The alkyl group constituting the alkyl ester of the alkyl (meth)acrylate may be in any of the n-, sec-, tert-, or iso- forms depending on the carbon position having a free valence. good.
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% by mass, more preferably 60 to 93% by mass, based on the raw material monomer (100% by mass) of the acrylic resin. % by mass, more preferably 70 to 90% by mass.

It is preferable that the raw material monomer of the acrylic resin contains a hydroxy group-containing (meth)acrylate as well as 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 the content of the raw material monomer of the acrylic resin (100% by mass %), preferably 2 to 50% by weight, more preferably 6 to 40% by weight, and even more preferably 10 to 30% by weight.

The raw material monomer of the acrylic resin may or may not contain monomers other than (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, N-methylolacrylamide, and the like.

(A) The weight average molecular weight (Mw) of the thermoplastic resin is not particularly limited, but is preferably 10,000 to 2,000,000, more preferably 100,000 to 1,500,000, even more preferably 150, 000 to 1,000,000.
(A) When the mass average molecular weight (Mw) of the thermoplastic resin is at least the above lower limit, the shape stability of the film for forming a protective film tends to be better. In addition, if the mass average molecular weight (Mw) of the thermoplastic resin (A) is below the above upper limit, the film for forming a protective film will easily follow the uneven surface of the object to be protected, and the The occurrence of voids and the like between the film and the film tends to be more suppressed.

(A) The glass transition temperature (Tg) (hereinafter also simply referred to as "Tg") of the thermoplastic resin is not particularly limited, but is preferably -60 to 70°C, more preferably -30 to 50°C, even more preferably -10 to 20°C.
(A) When the Tg of the thermoplastic resin is at least the above lower limit, the cohesive force of the film for forming a protective film tends to be better. Moreover, when the Tg of the thermoplastic resin (A) is below the above upper limit, the flexibility and adhesiveness of the film for forming a protective film tend to improve.

For example, the Tg of the acrylic resin can be calculated using the Fox equation 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 is the glass transition temperature of the homopolymer of each monomer that is the raw material for the acrylic resin, and W1, W2, ...Wm is the glass transition temperature of each monomer, which is the raw material for the acrylic resin.) It is the mass fraction of the monomer. However, W1+W2+...+Wm=1.)
For the glass transition temperature of the homopolymer of each monomer in the above Fox formula, values described in the Polymer Data Handbook, Adhesive Handbook, or Polymer Handbook can be used. For example, the Tg of methyl acrylate homopolymer is 10°C, the Tg of 2-hydroxyethyl acrylate homopolymer is -15°C, the Tg of 2-ethylhexyl acrylate is -70°C, and the Tg of 2-ethylhexyl methacrylate is -10°C.
Furthermore, Tg can also be determined in accordance with JIS K 7121 (2012).

(A) The thermoplastic resin may have a functional group. Examples of the functional group include a vinyl group, a (meth)acryloyl group, an amino group, a hydroxy group, a carboxy group, an isocyanate group, and the like.
(A) When the thermoplastic resin has a functional group, the functional group may be bonded to another compound via (H) a crosslinking agent, which will be described later, or may be bonded to another compound without using a (H) crosslinking agent. It may also be directly bonded to other compounds. When (A) the thermoplastic resin is bonded to another compound through a functional group (H) via a crosslinking agent or directly, the reliability of the protective film tends to be improved.
As the thermoplastic resin (A) having a functional group, an acrylic resin having a functional group is preferable, and an acrylic resin having a hydroxy group as a functional group is more preferable.

The content of the thermoplastic resin (A) in the resin composition for forming a protective film is not particularly limited, but is preferably 5 to 80% by mass based on the solid content (100% by mass) of the resin composition for forming a protective film. %, more preferably 7 to 50% by weight, even more preferably 10 to 30% by weight.
(A) When the content of the thermoplastic resin is at least the above lower limit, the flexibility and adhesion to the object to be protected tend to be better before curing of the film for forming a protective film. Moreover, when the content of the thermoplastic resin (A) is below the above upper limit, the flame retardance, mechanical strength, and heat resistance of the protective film tend to be better.

<(B) Epoxy resin>
Since the resin composition for forming a protective film contains the epoxy resin (B), the film for forming a protective film of this embodiment has thermosetting properties, and forms a protective film with excellent mechanical strength, heat resistance, etc. Become what you can.
(B) Epoxy resins may be used alone or in combination of two or more.

(B) As the epoxy resin, an epoxy resin having two or more epoxy groups in one molecule is preferable.
(B) Epoxy resins include known ones, such as bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin, and hydrogenated products thereof; phenol novolac type epoxy resin, cresol novolac type epoxy resin Novolac type epoxy resins such as orthocresol novolak type epoxy resins; aralkyl type epoxy resins such as phenol aralkyl type epoxy resins; dicyclopentadiene type epoxy resins; biphenyl type epoxy resins; naphthalene type epoxy resins; and the like.
Among these, dicyclopentadiene-type epoxy resins, bisphenol-type epoxy resins, and naphthalene-type epoxy resins are preferred from the viewpoint of handleability, heat resistance, etc. of the film for forming a protective film.

(B) The number average molecular weight (Mn) of the 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, or more. It is preferably 250 to 10,000, more preferably 300 to 3,000.

The epoxy equivalent of the epoxy resin (B) is not particularly limited, but is preferably 100 to 1,500 g/eq, more preferably 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 130 to 1,200 g/eq, more preferably 160 to 1,000 g/eq.
In addition, in this specification, "epoxy equivalent" means the number of grams (g/eq) of an epoxy resin containing 1 gram equivalent of epoxy group, and can be measured according to JIS K 7236:2001.

The content of the epoxy resin (B) in the resin composition for forming a protective film is not particularly limited, but is preferably 2 to 60% by mass based on the solid content (100% by mass) of the resin composition for forming a protective film. , more preferably 4 to 40% by weight, still more preferably 7 to 20% by weight.
(B) When the content of the epoxy resin is at least the above lower limit, the curability of the film for forming a protective film and the mechanical strength and heat resistance of the protective film tend to be better. Moreover, when the content of the epoxy resin (B) is below the above upper limit, the flexibility of the film for forming a protective film before curing tends to be better.

<(C) Inorganic filler>
By containing the inorganic filler (C) in the resin composition for forming a protective film, the film for forming a protective film of this embodiment has excellent shape retention properties, and the film for forming a protective film of this embodiment The protective film formed from this material has excellent flame retardancy, low thermal expansion, and low moisture absorption.
(C) Inorganic fillers may be used alone or in combination of two or more.

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

The average particle diameter (D ₅₀ ) of the inorganic filler (C) 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) The average particle diameter (D ₅₀ ) of the inorganic filler is determined by measuring the particle size distribution by the Coulter counter method using a Multisizer Three machine (manufactured by Beckman Coulter) or the like.

The content of the inorganic filler (C) in the resin composition for forming a protective film is not particularly limited, but is preferably 50% by mass or more based on the solid content (100% by mass) of the resin composition for forming a protective film. , more preferably 53% by mass or more, still more preferably 55% by mass or more, and preferably 90% by mass or less, more preferably 85% by mass or less, still more preferably 80% by mass or less.
(C) When the content of the inorganic filler is equal to or higher than the above lower limit, the shape retention of the film for forming a protective film, the flame retardance of the protective film, the low thermal expansion property, and the low hygroscopicity tend to be better. . Moreover, when the content of the inorganic filler (C) is below the above upper limit, the flexibility of the film for forming a protective film before curing tends to be better.

<(D) Nitrogen atom-containing compound containing no phosphorus atom>
By containing (D) a nitrogen atom-containing compound that does not contain a phosphorus atom (hereinafter also simply referred to as "(D) nitrogen atom-containing compound"), the resin composition for forming a protective film of this embodiment can be used for forming a protective film. The protective film formed from the film has excellent flame retardancy.
(D) The nitrogen atom-containing compound may be used alone or in combination of two or more.

(D) Examples of the nitrogen atom-containing compound include an aliphatic amine compound, an aromatic amine compound, a nitrogen atom-containing heterocyclic compound, a cyanide compound, an aliphatic amide compound, an aromatic amide compound, and urea. Among these, nitrogen atom-containing heterocyclic compounds are preferred from the viewpoint of flame retardancy.

Examples of the nitrogen atom-containing heterocyclic compound include compounds having a triazine ring and compounds having an isocyanurate ring. Among these, compounds having a triazine ring are preferred. The triazine ring possessed by the compound having a triazine ring may be any of a 1,2,3-triazine ring, a 1,2,4-triazine ring, or a 1,3,5-triazine ring, but 1,3, A 5-triazine ring is preferred.

Examples of compounds having a 1,3,5-triazine ring include melamine, melamine cyanurate, N ² ,N ⁴ -diethylmelamine, N,N'-diallylmelamine, hexamethylmelamine, acetoguanamine, benzoguanamine, and acrylic acid. Guanamine, methacryloguanamine, melam, ammeline, ammelide, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-ethoxy-1,3,5-triazine, 2, 4-diamino-6-propoxy-1,3,5-triazine, 2,4-diamino-6-isopropoxy-1,3,5-triazine, 2,4-diamino-6-nonyl-1,3,5 - Triazines and the like. Among these, melamine cyanurate is preferred from the viewpoint of flame retardancy of the protective film and flexibility of the film for forming the protective film before curing.

(D) The content of nitrogen atoms in the nitrogen atom-containing compound is not particularly limited, but from the viewpoint of further improving the flame retardance of the protective film, the content of nitrogen atoms in the (D) nitrogen atom-containing compound (100% by mass) is The amount is preferably 10 to 65% by weight, more preferably 30 to 60% by weight, and even more preferably 40 to 55% by weight.

The content of the nitrogen atom-containing compound (D) in the resin composition for forming a protective film is 5.5 to 10% by mass based on the solid content (100% by mass) of the resin composition for forming a protective film.
(D) When the content of the nitrogen atom-containing compound is at least the above lower limit, the flame retardance of the protective film becomes good. Moreover, when the content of the nitrogen atom-containing compound (D) is at most the above upper limit, the flexibility of the film for forming a protective film before curing becomes good.
The content of the nitrogen atom-containing compound (D) in the resin composition for forming a protective film is preferably 6.0 to 9 from the viewpoint of flexibility before curing of the film for forming a protective film and flame retardancy of the protective film. .7% by weight, more preferably 6.5-9.5% by weight, even more preferably 6.7-9.3% by weight.

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

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

When the resin composition for forming a protective film contains (E) a curing accelerator, the content of the curing accelerator (E) in the resin composition for forming a protective film is not particularly limited, but (B) epoxy resin 100 It is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, and even more preferably 1 to 3 parts by weight.
(E) When the content of the curing accelerator is at least the above lower limit, the curability of the film for forming a protective film tends to be better. Moreover, when the content of the curing accelerator (E) is below the above upper limit, the homogeneity of the cured product tends to be better.

<(F) Colorant>
The resin composition for forming a protective film may contain (F) a coloring agent.
By containing the colorant (F) in the resin composition for forming a protective film, the protective film formed from the film for forming a protective film of this embodiment is provided with laser printability, light shielding property, designability, etc. I can do it.
(F) Colorants may be used alone or in combination of two or more.

Examples of the coloring agent (F) include known ones, such as inorganic pigments, organic pigments, and organic dyes.
Examples of inorganic pigments include carbon black, cobalt pigments, iron pigments, chromium pigments, titanium pigments, vanadium pigments, zirconium pigments, molybdenum pigments, ruthenium pigments, platinum pigments, and ITO (indium pigments). Examples include tin oxide (tin oxide) dyes and ATO (antimony tin oxide) dyes.
Examples of organic pigments and organic dyes include aminium pigments, cyanine pigments, merocyanine pigments, croconium pigments, squalium pigments, azulenium pigments, polymethine pigments, naphthoquinone pigments, pyrylium pigments, and phthalocyanine pigments. Pigments, naphthalocyanine dyes, naphtolactam dyes, azo dyes, condensed azo dyes, indigo dyes, perinone dyes, perylene dyes, dioxazine dyes, quinacridone dyes, isoindolinone dyes, quinophthalone dyes, Pyrrole dyes, thioindigo dyes, metal complex dyes (metal complex dyes), dithiol metal complex dyes, indolephenol dyes, triallylmethane dyes, anthraquinone dyes, naphthol dyes, azomethine dyes, benzimidazolone Examples include pyranthrone dyes, pyranthrone dyes, thren dyes, and the like.

When the resin composition for forming a protective film contains a coloring agent (F), the content of the coloring agent (F) in the resin composition for forming a protective film is not particularly limited, but from the viewpoint of obtaining an appropriate coloring effect. Based on the solid content (100% by mass) of the resin composition for forming a protective film, preferably 0.01 to 10% by mass, more preferably 0.05 to 7.5% by mass, and even more preferably 0.1% by mass. ~5% by weight, particularly preferably 1-3% by weight.

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

(G) Examples of the epoxy resin curing agent include compounds having two or more functional groups in one molecule that can react with epoxy groups.
Examples of the functional group that can react with an epoxy group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxy group, and an anhydride of an acid group. Among these, phenolic hydroxyl groups, amino groups, and groups obtained by anhydrating acid groups are preferable, and phenolic hydroxyl groups and amino groups are more preferable.

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

(G) Among the epoxy resin curing agents, the molecular weight of non-resin components such as biphenol and dicyandiamide is not particularly limited, but is preferably 60 to 500, more preferably 70 to 200, and still more preferably 80 to 120. .

When the resin composition for forming a protective film contains (G) an epoxy resin curing agent, 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, preferably 0.1 to 200 parts by mass, more preferably 0.5 to 100 parts by mass, and even more preferably 0 to 100 parts by mass of the epoxy resin (B). .7 to 50 parts by weight, particularly preferably 1 to 10 parts by weight.

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

(H) As a crosslinking agent, for example, an organic polyvalent isocyanate compound, an organic polyvalent imine compound, a metal chelate type crosslinking agent (a crosslinking agent having a metal chelate structure), an aziridine type crosslinking agent (a crosslinking agent having an aziridinyl group), etc. can be mentioned.

Examples of organic polyvalent isocyanate compounds include aromatic polyvalent isocyanate compounds, aliphatic polyvalent isocyanate compounds, and alicyclic polyvalent isocyanate compounds (hereinafter, these compounds are collectively abbreviated as "aromatic polyvalent isocyanate compounds, etc.") trimers, isocyanurates and adducts of the aromatic polyisocyanate compounds, etc.; terminal isocyanate urethane prepolymers obtained by reacting the aromatic polyisocyanate compounds, etc. with polyol compounds, etc. can be mentioned.
The above-mentioned "adduct" refers to a reaction product of the above-mentioned aromatic polyvalent isocyanate compound and a low-molecular active hydrogen-containing compound such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. means. Specific examples include tolylene diisocyanate adducts of trimethylolpropane, which will be described later.

Examples of organic polyvalent isocyanate 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; examples include lysine diisocyanate.

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

Among the above options, as the crosslinking agent (H), an organic polyvalent isocyanate compound is preferable, and it is composed of tolylene diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate for all or part of the hydroxyl groups of a polyol such as trimethylolpropane. A compound to which one or more selected from the group is added is more preferable, and a tolylene diisocyanate adduct of trimethylolpropane is even more preferable.

(H) When using an organic polyvalent isocyanate compound as the crosslinking agent, it is preferable that the thermoplastic resin (A) has a hydroxy group. When the (H) crosslinking agent has an isocyanate group and the (A) thermoplastic resin has a hydroxyl group, the reaction between the (H) crosslinking agent and the (A) thermoplastic resin creates a crosslinked structure in the film for forming a protective film. can be easily introduced.

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

<(I) Coupling agent>
The protective film-forming resin composition may contain (I) a coupling agent.
When the resin composition for forming a protective film contains the coupling agent (I), 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.

Examples of the coupling agent (I) include silane coupling agents and titanate coupling agents. Among these, silane coupling agents are preferred.
As the coupling agent (I), for example, one having a functional group that can react with (A) a thermoplastic resin, (B) an epoxy resin, etc. having a functional group is preferable. 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, and an imidazole group. Among these, those having a glycidyl group are preferred.

Examples of the coupling agent (I) include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 2-glycidyloxypropylmethyldimethoxysilane, (3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-amino ethylamino)propylmethyldiethoxysilane, 3-anilinopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl) ) Tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane, and partially hydrolyzed condensates of one or more of these. Among these, 3-glycidyloxypropyltrimethoxysilane is preferred.

When the resin composition for forming a protective film contains (I) a coupling agent, the content of the coupling agent (I) in the resin composition for forming a protective film is not particularly limited, but (A) the thermoplastic resin and (B) 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 parts by mass, based on 100 parts by mass of the epoxy resin. .
When the content of the coupling agent (I) is at least the above lower limit, the dispersibility of the inorganic filler (C), the adhesiveness of the protective film, the water resistance, etc. tend to be better. Moreover, when the content of the coupling agent (I) is below the above upper limit, the generation of outgas tends to be further suppressed.

<Solvent>
The resin composition for forming a protective film may contain a solvent from the viewpoint of facilitating the formation of a film.
One type of solvent may be used alone, or two or more types may be used in combination.

Examples of solvents 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; and ketones such as acetone and methyl ethyl ketone. ; ethers such as tetrahydrofuran; amides (compounds having an amide bond) such as dimethylformamide and N-methylpyrrolidone; and the like. Among these, toluene, ethyl acetate, and methyl ethyl ketone are preferred.

<Other ingredients>
The resin composition for forming a protective film may or may not contain components other than the above-mentioned components.
Other components include, for example, resin components other than the above-mentioned components, plasticizers, antistatic agents, antioxidants, gettering agents, flame retardants other than component (D), and the like.
Regarding the other components, one kind may be used alone, or two or more kinds may be used in combination.
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.

<Method for producing resin composition for forming protective film>
The resin composition for forming a protective film can be manufactured by blending the components for forming the resin composition.
The order of addition when blending each component is not particularly limited, and two or more components may be added simultaneously or sequentially.
When using a solvent, any component other than the solvent may be used after being diluted with the solvent, or may be mixed with other components without being diluted with the solvent.
The method of mixing each component is not particularly limited, and for example, known methods such as mixing by rotating a stirring bar, stirring blade, etc.; mixing using a mixer; mixing by applying ultrasonic waves; You can select as appropriate.
The temperature and time for adding and mixing each component are not particularly limited, and may be adjusted as appropriate depending on the components used.

[Thickness and shape of protective film forming film]
The thickness of the film for forming a protective film of this embodiment is not particularly limited, but is preferably 1 to 100 μm, more preferably 3 to 75 μm, and still more preferably 5 to 50 μm.
When the thickness of the film for forming a protective film is equal to or more than the above lower limit, the protective function of the protective film tends to be better. Moreover, when the thickness of the film for forming a protective film is less than or equal to the above upper limit, it is not only economically efficient, but also tends to facilitate processing such as cutting of the protective film.

The shape of the protective film forming 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 protective film forming film has a circular shape in plan view, its diameter is, for example, 200 mm (for 8-inch wafers), 300 mm (for 12-inch wafers), etc.

[Elongation at break of protective film forming film]
The elongation at break of the film for forming a protective film of the present 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, still more preferably 120% or more, and particularly preferably is 140% or more.
When the elongation at break 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 before being applied to the object to be protected.
The upper limit of the elongation at break of the film for forming a protective film of the present embodiment at a tensile speed of 1,000 mm/min is not particularly limited, but may be 1,500% or less, and may be 1,000% or less. It may be 500% or less.
The elongation at break 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 Examples.

[How to use the film for forming a protective film]
The film for forming a protective film of this embodiment can be attached to an object to be protected by pressing it onto the object. When pressing, the film for forming a protective film may be heated if necessary.

Examples of objects to be protected to which the film for forming a protective film of this embodiment is attached include semiconductor wafers, semiconductor chips, and the like. When attaching a protective film-forming film 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 attached. By dividing into pieces, it is possible to obtain a semiconductor chip with a protective film having 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; glass wafers; and the like.
Examples of semiconductor chips include those obtained by dividing the above semiconductor wafer into individual pieces.

It is preferable that the semiconductor wafer or semiconductor chip to which the film for forming a protective film of this embodiment is attached has been subjected to 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 still more preferably 10 to 45 μm.

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

The timing of applying the protective film-forming film of this embodiment to the object to be protected and the timing of thermosetting it are not particularly limited, and may be appropriately determined depending on the process to which the protective film-forming film of this embodiment is applied.
For example, in the process of manufacturing semiconductor chips by back-grinding a semiconductor wafer and then singulating it, there is a At the same time, a protective film-forming film may be attached to a semiconductor wafer or a semiconductor chip and thermally cured to form a protective film.
However, from the perspective of suppressing damage etc. when singulating semiconductor wafers, a protective film forming film is pasted on the back side of the semiconductor wafer after grinding the back side of the semiconductor wafer and before singulation. It is preferable to form a semiconductor wafer with a protective film by thermal curing.
As a method for dividing the semiconductor wafer with a protective film into pieces, a known singulation method such as a blade dicing method, a laser dicing method, a stealth dicing (registered trademark) method, etc. can be applied.
Semiconductor chips with a protective film are obtained by dividing the semiconductor wafer with a protective film into pieces.

[Method for manufacturing film for forming protective film]
The film for forming a protective film can be manufactured, for example, by forming a resin composition for forming a protective film into a film. Specifically, for example, a protective film-forming film is formed on the support sheet by coating a protective film-forming resin composition on a support sheet such as a release film and drying as necessary. I can do it.

[Composite sheet for forming a protective film according to the first embodiment]
The composite sheet for forming a protective film of the first aspect of this embodiment has a structure in which the film for forming a protective film of this embodiment is sandwiched between two release films.
Note that in this specification, the term "release film" refers to a film that has a peelable function, and is a film that is applied to the surface of a protective film-forming film in order to protect the protective film-forming film before being applied to the object to be protected. It can be attached.
Preferred embodiments of the film for forming a protective film included in the composite sheet for forming a protective film of the first embodiment are as described above.

<Structure of the composite sheet for forming a protective film according to the first embodiment>
FIG. 1 is a cross-sectional view schematically showing an example of a composite sheet for forming a protective film according to the first embodiment. Note that the drawings used in the following explanation may show important parts enlarged for convenience, and the dimensional ratios of each component are not necessarily the same as in reality.

The composite sheet 1 for forming a protective film shown in FIG. 1 has a first release film 111 on one surface 10a of the film 10 for forming a protective film, and has a second release film 112 on the other surface 10b.
A composite sheet for forming a protective film having such a configuration is suitable for storing, for example, in the form of a roll.
The first release film 111 and the second release film 112 may be the same or different. For example, the first release film 111 and the second release film 112 may have different release forces from each other when they are removed from the protective film forming film 10.

<Release film>
Examples of release films that can be used in the composite sheet for forming a protective film include those obtained by coating a release agent on a release film base material.
Examples of base materials for release films include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, and polyethylene naphthalate film. Butylene 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, Transparent films such as polyimide films and fluororesin films; crosslinked films of these films; colored films of these films; opaque films; papers such as high-quality paper, glassine paper, and kraft paper; and the like. These may be used in a single layer or in a stack of two or more layers.

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 resins. One type of release agent may be used alone, or two or more types may be used in combination.

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 at least the above lower limit, the deformation resistance of the composite sheet for forming a protective film tends to be better. Moreover, when the thickness of the release film is less than or equal to the above upper limit value, appropriate flexibility is obtained, and the handling properties of the composite sheet for forming a protective film tend to be better.

<Method for manufacturing 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 manufactured according to the above-mentioned [Method for manufacturing a film for forming a protective film]. Specifically, for example, after forming a protective film-forming film on the release film with the object to which the protective film-forming resin composition is applied as the release-treated surface of the release film, the protective film-forming film is The protective film-forming composite sheet of the first embodiment can be manufactured by attaching the release-treated surface of another release film to the exposed surface.

[Second embodiment of composite sheet for forming a protective film]
The composite sheet for forming a protective film according to the second aspect of the present embodiment is a composite sheet for forming a protective film, which has a base material, an adhesive layer, and a film for forming a protective film according to the present embodiment in this order. .
Preferred embodiments of the film for forming a protective film included in the composite sheet for forming a protective film of the second embodiment are as described above.

The composite sheet for forming a protective film of the second embodiment has a base material and an adhesive layer in addition to the film for forming a protective film. Therefore, for example, when the protective film forming film of the protective film forming composite sheet of the second aspect is attached to a semiconductor wafer and thermally cured to form a protective film, the protective film is supported by the base material through the adhesive layer. A semiconductor wafer with a film is obtained. A semiconductor wafer with a protective film supported by a base material via an adhesive layer can be separated into individual pieces by fixing the surface on the base material side, for example. That is, the composite sheet for forming a protective film of the second aspect can be used as one in which a film for forming a protective film and a dicing sheet having a base material and an adhesive layer are integrated.

<Structure of the composite sheet for forming a protective film according to the second embodiment>
The composite sheet for forming a protective film of the second aspect may consist only of a base material, an adhesive layer, and a film for forming a protective film, but other than the base material, the adhesive layer, and the film for forming a protective film. It may have the following constituent members. Other structural members include, for example, a release film laminated on the surface of the protective film-forming film opposite to the pressure-sensitive adhesive layer.
Preferred embodiments of the release film that may be included in the composite sheet for forming a protective film of the second embodiment are as described above.

2 and 3 are cross-sectional views schematically showing an example of a composite sheet for forming a protective film according to the second aspect.
In each figure, the same components as those shown in the already explained figures are given the same reference numerals as in the already explained figures, and detailed explanation thereof will be omitted.

A composite sheet 1A for forming a protective film shown in FIG. 2 has an adhesive layer 13 on a base material 12 and a film 10 for forming a protective film on the adhesive layer 13. In the protective film-forming composite sheet 1A, a release film 11 is further laminated on the surface 10a (upper surface) of the protective film-forming film 10 and the surface 13a (upper surface) of the adhesive layer 13. In the composite sheet 1A for forming a protective film, the back surface of a semiconductor wafer (not shown) is attached to a part of the central area of the surface 10a of the film 10 for forming a protective film, with the release film 11 removed. Furthermore, the area near the peripheral edge of the protective film forming film 10 is used by being attached to a jig such as a ring frame.

The composite sheet 1B for forming a protective film shown in FIG. It is the same as the protective film forming composite sheet 1A shown in FIG. 2, except that a release film 11 is laminated on the surface 10a (top surface) and the surface 14a (top surface) of the jig adhesive layer 14. be.
The jig adhesive layer 14 may have, for example, a single layer structure containing an adhesive component, or a multi-layer structure in which layers containing an adhesive component are laminated on both sides of a sheet serving as a core material. It may be of a structure.
In the protective film forming composite sheet 1B, the back side of a semiconductor wafer (not shown) is attached to the front surface 10a of the protective film forming film 10 with the release film 11 removed, and the jig adhesive layer 14 The upper surface of the surface 14a is used by being attached to a jig such as a ring frame.

The composite sheet for forming a protective film according to the second aspect of this embodiment is not limited to the one shown in FIGS. 2 and 3, but may be any of the ones shown in FIGS. 2 and 3 within the range that does not impair the effects of this embodiment. The structure of the parts may be changed or deleted, or other structures may be added to those described above.

<Base material>
Examples of the constituent materials of the base material include various resins.
Examples of the resin constituting the base material include polyethylene such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE); polypropylene, polybutene, polybutadiene, polymethylpentene, norbornene resin, etc. Polyolefins other than polyethylene; ethylene copolymers such as ethylene-vinyl acetate copolymers, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, and ethylene-norbornene copolymers (Copolymers obtained using ethylene as a monomer); Vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers (resins obtained using vinyl chloride as a monomer); Polystyrene; Polycycloolefin; Polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene isophthalate, polyethylene-2,6-naphthalene dicarboxylate, fully aromatic polyesters in which all constituent units have an aromatic cyclic group; two or more types Polyester copolymer; poly(meth)acrylic acid ester; polyurethane; polyurethane acrylate; polyimide; polyamide; polycarbonate; fluororesin; polyacetal; modified polyphenylene oxide; polyphenylene sulfide; polysulfone; polyether ketone; one of these resins or Examples include crosslinked resins in which two or more types are crosslinked; modified resins such as ionomers using one or more of these resins. One type of resin constituting the base material may be used alone, or two or more types may be used in combination.
Among these, polypropylene and polybutylene terephthalate are preferred from the viewpoint of heat resistance.

In addition to the resins mentioned above, the base material contains various known additives such as fillers, colorants, antistatic agents, antioxidants, organic lubricants, catalysts, and softeners (plasticizers). Good too.

The base material may be surface-treated to improve adhesion with other layers such as the adhesive layer.
Surface treatment methods include, for example, unevenness treatment by sandblasting, solvent treatment, etc.; oxidation such as corona discharge treatment, electron beam irradiation treatment, plasma treatment, ozone/ultraviolet irradiation treatment, flame treatment, chromic acid treatment, hot air treatment, etc. treatment; primer treatment; etc. Among these, those subjected to electron beam irradiation treatment are preferred from the viewpoint of suppressing the generation of fragments of the base material due to blade friction when applying the protective film-forming composite sheet to blade dicing.

The base material may consist of only one layer, or may consist of two or more layers. When the base material consists of multiple layers, the layers constituting the multiple layers may be the same or different.
Furthermore, the base material prevents the base material from adhering to other sheets and from adhering to the suction table, for example, when storing the antistatic coating layer and the composite sheet for forming a protective film on top of each other. It may also have a layer or the like for this purpose.

The thickness of the base material 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 base material is within the above range, the flexibility and adhesion of the composite sheet for forming a protective film tend to be better.

<Adhesive layer>
The adhesive layer is an adhesive layer provided between the base material and the film for forming a protective film.
The adhesive layer may consist of only one layer, or may consist of two or more layers. When the adhesive layer consists of multiple layers, the layers constituting the multiple layers may be the same or different.

Examples of the adhesive resin constituting the adhesive layer include adhesive resins such as acrylic resin, urethane resin, rubber resin, silicone resin, epoxy resin, polyvinyl ether resin, polycarbonate resin, and ester resin. 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 include block copolymers, random copolymers, and graft copolymers. It may be either.
Among these, acrylic resin is preferred from the viewpoint of exhibiting excellent adhesive strength.

In addition, in this embodiment, "adhesive resin" is a concept that includes both resins that have adhesiveness and resins that have adhesive properties. It also includes resins that exhibit adhesiveness when used in combination with other components such as additives; resins that exhibit adhesiveness in the presence of triggers such as heat and water; and the like.

The thickness of the adhesive layer is not particularly limited, but is preferably 3 to 30 μm, more preferably 4 to 20 μm, and still more preferably 5 to 17 μm.
When the thickness of the adhesive layer is at least the above lower limit, the tack and adhesive strength tend to be better. Moreover, when the thickness of the adhesive layer is less than or equal to the above upper limit value, blade dicing suitability and pick-up suitability tend to be better when the composite sheet for forming a protective film is applied to blade dicing.

The adhesive layer may be formed using an energy ray curable adhesive or may be formed using a non-energy ray curable adhesive. Note that the non-energy ray curable adhesive includes a thermosetting adhesive and a non-curing adhesive.

<Method for manufacturing a composite sheet for forming a protective film according to the second embodiment>
The composite sheet for forming a protective film according to the second aspect can be manufactured by sequentially stacking the layers constituting the composite sheet for forming a protective film in a corresponding positional relationship. Each layer can be formed according to the above-described [method for producing a film for forming a protective film].
Specifically, for example, a protective film-forming resin composition may be applied to the surface of an adhesive layer laminated on a base material to form a protective film-forming film on the adhesive layer, or A film for forming a protective film is formed in advance on the release-treated surface of the release film, and the exposed surface of the film for forming a protective film is bonded to the surface of the adhesive layer laminated on the base material to form a protective film. A film may be laminated onto the adhesive layer.
Similarly, when laminating an adhesive layer on a base material, the composition may be applied to the surface of the base material to form the adhesive layer, or the composition may be applied to the adhesive layer formed on the release-treated surface of the release film. The release film may be removed after the exposed surface of the substrate is bonded to the surface of the base material. Even when the composite sheet for forming a protective film of the second embodiment has an arbitrary layer such as an intermediate layer, the arbitrary layer may be provided at a necessary position according to the above method.

[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 description of the protective film-forming film used to form the protective film of the protective film-equipped semiconductor chip of this embodiment, the protective film formed from the protective film-forming film, and the preferred embodiments of the semiconductor chip can be found above. That's exactly what I did.
The size of the semiconductor chip in plan view is not particularly limited, but is preferably less than 600 mm ² , more preferably less than 400 mm ² , and even more preferably less than 300 mm ² . Note that "planar view" refers to viewing in the thickness direction.
The shape of the semiconductor chip in plan view may be square, or may be elongated such as a rectangle.
The semiconductor chip with a protective film of this embodiment can be manufactured by the method described in the method of using the film for forming a protective film of this embodiment.

[Semiconductor device]
The semiconductor device of this embodiment is a semiconductor device including the semiconductor chip with a protective film of this embodiment.
Examples of the semiconductor device of this embodiment include a semiconductor package in which the semiconductor chip with a protective film of this embodiment is flip-chip connected to a substrate having a circuit.

The present invention will be specifically explained with reference to the following examples, but the present invention is not limited to the following examples. In addition, the physical property values in each example are values measured by the following method.

[Mass average molecular weight (Mw)]
Measurements were made using a gel permeation chromatography device (manufactured by Tosoh Corporation, product name "HLC-8020") under the following conditions, and the values measured in terms of standard polystyrene were used.
(Measurement condition)
・Column: “TSK guard column SuperH-H”, “TSK gel SuperHM-H”, “TSK gel SuperHM-H”, “TSK gel SuperH2000” (all manufactured by Tosoh Corporation) connected in sequence ・Column temperature: 40°C
・Developing solvent: Tetrahydrofuran ・Flow rate: 1.0 mL/min

[Thickness of each layer]
Using a constant pressure thickness measuring device manufactured by Techrock Co., Ltd. (model number: "PG-02J", standard specifications: JISK6783, Z1702, Z1709 compliant), the thickness was measured at 5 arbitrary locations at 23 ° C. The average value of the measured values was calculated.

[Manufacture of protective film forming film]
Examples 1 to 3, Comparative Examples 1 to 3
(Manufacture of resin composition)
After dissolving or dispersing each component shown in Table 1 in a mixed solvent of methyl ethyl ketone, toluene, and ethyl acetate according to the formulation shown in Table 1, the mixture was stirred at 23°C to produce a resin with a solid content concentration of 62% by mass. A composition was obtained.

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

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

(Flame retardancy evaluation method)
Two films with release film 2 removed from the films for forming a protective film with double-sided release films obtained in each example were prepared, and the exposed surfaces of the films for forming a protective film were pressed together using a roll laminator heated to 70°C. After laminating them directly to produce a film for forming a protective film having a thickness of about 50 μm, the release film 1 was removed from one side. Place a silicon wafer piece (a 100 μm thick silicon wafer with a No. 2,000 polished surface cut into a rectangular shape with a length of 125 mm and a width of 13 mm) so that the exposed protective film forming film becomes the attachment surface. Attached. Thereafter, the release film 1 was removed, and the film for forming a protective film attached to the silicon wafer piece was cured by heating at 140° C. for 2 hours in an air atmosphere to form a protective film. Next, unnecessary portions of the protective film were cut and removed so as to have the same shape as the silicon wafer piece, and the obtained silicon wafer piece with the protective film was used as a test piece for flame retardancy testing. Note that five test pieces were prepared in each example.
The obtained test piece was kept in a constant temperature room with a temperature of 23°C and a humidity of 50% for 48 hours, and was tested under the UL94 test (combustion of plastic materials for equipment parts) specified by Underwriters Laboratories (UL) in the United States. A flame retardancy test was conducted in accordance with the UL94V test (vertical combustion test). In addition, after carrying out the flame contact test on the five test pieces included in the UL94V test, the length of unburned remains on each test piece was measured, and the average value of the unburned length of the five test pieces was calculated. Calculated.
Table 1 shows the average value of the grade and unburned length of the test piece in the UL94V test. Note that "NOT" in Table 1 means that the V-2 standard in the UL94V test could not be met.

(Method of measuring elongation at break)
Prepare one sheet from which release film 2 has been removed from the film for forming a protective film with a double-sided release film obtained in each example, fold it in half with the exposed surface of the film for forming a protective film inside, and heat it to 70°C. The protective film-forming films were directly laminated together by pressing with a rolled laminator. Next, one of the release films 1 was removed, the film was bent in half again with the exposed protective film forming film surface facing inward, and pressed under the same conditions as above. Furthermore, the same operation was repeated to produce a film for forming a protective film with a double-sided release film having a thickness of about 200 μm. The film for forming a protective film with a double-sided release film was cut into pieces with a length of 60 mm and a width of 15 mm, and the release films on both sides were removed to obtain a test piece for measuring the elongation at break.
The test piece obtained above was tested using a tensile tester (manufactured by Shimadzu Corporation, trade name "Autograph AG-IS1kN") at 23°C, relative humidity 50%, and tensile speed 1,000 mm/min. A tensile test was conducted under the condition that the distance between the chucks was 10 mm, and the elongation at break was measured.
Note that the elongation at break is calculated by the following formula.
Breaking elongation (%) = {(LL ₀ )/L ₀ }×100
L = Length of test piece at break L ₀ = Length of test piece before test

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)

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

<(C) Inorganic filler>
Spherical silica (manufactured by Admatex Co., Ltd., trade name "SC2050MA", average particle diameter (D ₅₀ ) 0.5 μm)

<(D) Nitrogen atom-containing compound>
Melamine cyanurate (manufactured by Nissan Chemical Co., Ltd., product name "MC-6000")

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

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

<(G) Epoxy resin curing agent>
Dicyandiamide type latent curing agent (manufactured by ADEKA Co., Ltd., trade name "ADEKA Hardener EH-3636AS", active hydrogen equivalent 21g/eq)

<(H) Crosslinking agent>
Tolylene diisocyanate adduct of trimethylolpropane

<(I) Coupling agent>
3-glycidyloxypropyltrimethoxysilane

From Table 1, it can be seen that the protective film forming films of Examples 1 to 3 of the present embodiment have excellent flexibility before curing, and the protective film also has excellent flame retardancy. On the other hand, the protective film formed from Comparative Example 1 in which (D) the nitrogen atom-containing compound was not blended and (D) the film for forming a protective film in which the content of the nitrogen atom-containing compound was less than 5.5% by mass was flame retardant. The film for forming a protective film of Comparative Example 3, in which the content of the nitrogen atom-containing compound (D) exceeded 10% by mass, had poor flexibility before curing.

1, 1A, 1B Composite sheet for forming a protective film 10 Film for forming a protective film 10a, 10b Surface of the film for forming a protective film on the release film side 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 adhesive layer for jig on the release film side

Claims (14)

Protection formed using a resin composition containing (A) a thermoplastic resin, (B) an epoxy resin, (C) an inorganic filler, and (D) a nitrogen atom-containing compound that does not contain a phosphorus atom. A film for film formation,
The content of the nitrogen atom-containing compound (D) that does not contain a phosphorus atom in the resin composition is 5.5 to 10% by mass with respect to the solid content (100% by mass) of the resin composition. Film for forming a protective film. The film for forming a protective film according to claim 1, wherein the nitrogen atom-containing compound (D) that does not contain a phosphorus atom is a nitrogen atom-containing heterocyclic compound. The film for forming a protective film according to claim 2, wherein the nitrogen atom-containing heterocyclic compound is a compound having a triazine ring. The film for forming a protective film according to claim 3, wherein the compound having a triazine ring is melamine cyanurate. The film for forming a protective film according to any one of claims 1 to 4, wherein the thermoplastic resin (A) is an acrylic resin. Any one of claims 1 to 5, wherein the content of the inorganic filler (C) in the resin composition is 50% by mass or more based on the solid content (100% by mass) of the resin composition. A film for forming a protective film as described in . The film for forming a protective film according to any one of claims 1 to 6, wherein the resin composition further contains (E) a curing accelerator. The film for forming a protective film according to any one of claims 1 to 7, wherein the resin composition further contains (F) a colorant. The film for forming a protective film according to any one of claims 1 to 8, which has a breaking elongation of 50% or more at a tensile speed of 1,000 mm/min. The film for forming a protective film according to any one of claims 1 to 9, which is attached to the back side of a semiconductor wafer and used for manufacturing a semiconductor chip with a protective film. A composite sheet for forming a protective film, wherein the film for forming a protective film according to any one of claims 1 to 10 is sandwiched between two release sheets. A composite sheet for forming a protective film, comprising a base material, an adhesive layer, and the film for forming a protective film according to any one of claims 1 to 10, in this order. A semiconductor chip with a protective film, comprising a protective film that is a cured product of the film for forming a protective film according to any one of claims 1 to 10. A semiconductor device comprising the protective film-equipped semiconductor chip according to claim 13.