Composite sheet for forming protective film and method for manufacturing semiconductor device

Abstract

To provide a composite sheet for forming a protective film, which enables easy formation of a joint made of a joining material for connecting members to be joined, and a method for manufacturing a semiconductor device using the composite sheet for forming a protective film.SOLUTION: A composite sheet for forming a protective film used to form a protective film on a protruding electrode forming surface of a member with protruding electrodes on which protruding electrodes are formed, includes a base material, an adhesive layer, a sintered material layer, and a protective film forming layer in this order, and has an interface (X) where the adhesive layer and the sintered material layer are in direct contact, and an interface (Y) where the sintered material layer and the protective film forming layer are in direct contact.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] A known method for joining components together using a conductive joint (conductive joint) involves placing a joint material containing metal particles and a binder between the components to be joined, heating the components and the joint material while applying pressure, and firing the joint material to form a conductive joint. According to this method, the binder decomposes when the joint material is fired, causing the metal particles to adhere to each other and form a conductive joint, which bonds the components together.

[0003] As a method for joining components together using a conductive joint, for example, a method has been disclosed in which a joining material containing silver nanoparticles, silver carbonate or silver oxide, and carboxylic acids containing crystals is used, and the joining material is sandwiched between the components to be joined, and then the joining material is heated and pressurized so that the temperature of the joining material is equal to or higher than the joining temperature, thereby joining the components together (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-279649 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the wiring density of electronic components has been increasing, which has led to the miniaturization of terminal electrodes and the narrowing of the distance between terminal electrodes (pitch).As a result, it is becoming more difficult to precisely supply and apply bonding material to terminal electrodes and bond components together.

[0006] Therefore, the inventor focused on a composite sheet for forming a protective film for forming a protective film on the protruding electrode forming surface of a member with protruding electrodes, and came up with the idea of ​​easily forming a joint made of a joining material for connecting components to be joined, and conducted various studies.

[0007] Therefore, the object of the present invention is to provide a composite sheet for forming a protective film that can easily form a joint made of a joining material for connecting components to be joined, and a method for manufacturing a semiconductor device using the composite sheet for forming a protective film. [Means for solving the problem]

[0008] According to the present invention, the following [1] to [7] are provided. [1] A composite sheet for forming a protective film for forming a protective film on a protruding electrode-formed surface of a member with protruding electrodes, The adhesive layer includes a substrate, a pressure-sensitive adhesive layer, a fired metal material layer, and a protective film-forming layer in this order; An interface (X) where the pressure-sensitive adhesive layer and the fired metal material layer are in direct contact; The composite sheet for forming a protective film has an interface (Y) where the fired metal material layer and the protective film forming layer are in direct contact with each other. [2] The composite sheet for forming a protective film according to the above [1], wherein the adhesive strength of the interface (Y) is smaller than the adhesive strength of the interface (X). [3] The composite sheet for forming a protective film according to [2] above, wherein the adhesive strength between the bump electrodes and the fired metal material layer is greater than the adhesive strength at the interface (X). [4] The composite sheet for forming a protective film according to any one of the above [1] to [3], wherein the fired metal material layer has a thickness of less than 100 μm. [5] The composite sheet for forming a protective film according to any one of the above [1] to [4], further comprising a buffer layer between the substrate and the pressure-sensitive adhesive layer. [6] A step of attaching a protective film forming layer of the composite sheet for forming a protective film according to any one of the above [1] to [5] to a projecting electrode forming surface of a member with projecting electrodes on which projecting electrodes are formed; separating the composite sheet for forming a protective film at an interface (Y) to prepare a laminate of the member with protruding electrodes and the protective film forming layer. [7] The method for manufacturing a semiconductor device according to [6] above, further comprising the step of connecting the electrodes of the substrate and the protruding electrodes of the laminate by sintering. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a composite sheet for forming a protective film that can easily form a joint made of a joining material for connecting components to be joined, and a method for manufacturing a semiconductor device using the composite sheet for forming a protective film. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view showing a first aspect of a composite sheet for forming a protective film according to the present embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view showing a second aspect of the composite sheet for forming a protective film of the present embodiment. [Figure 3] 5A to 5C are schematic cross-sectional views showing a part of the method for manufacturing the semiconductor device according to the present embodiment. [Figure 4] 5A to 5C are schematic cross-sectional views showing a part of the method for manufacturing the semiconductor device according to the present embodiment. [Figure 5] 5A to 5C are schematic cross-sectional views showing a part of the method for manufacturing the semiconductor device according to the present embodiment. [Figure 6] 5A to 5C are schematic cross-sectional views showing a part of the method for manufacturing the semiconductor device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] In this specification, the weight average molecular weight (Mw) and number average molecular weight (Mn) 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.

[0012] 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."

[0013] 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.

[0014] In this specification, "energy ray curable" means a property of being cured by irradiation with energy rays. In addition, in this specification, "thermosetting" means a property of being cured by heating, and "non-curable" means a property of not being cured by heating or irradiation with energy rays.

[0015] In this specification, for example, "(meth)acrylic acid" refers to both "acrylic acid" and "methacrylic acid," and the same applies to other similar terms.

[0016] In this specification, the term "member with protruding electrodes" refers to a "semiconductor wafer with protruding electrodes" or a "semiconductor chip with protruding electrodes." Furthermore, 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 to the circuit side. In this specification, the term "projecting electrode" refers to a projecting electrode of a shape generally used on the circuit formation surface of a semiconductor wafer, for example, and refers to bumps such as ball bumps, columnar electrodes, and the like. In addition, in this specification, the term "member with bumps" means a "semiconductor wafer with bumps" or a "semiconductor chip with bumps."

[0017] In this specification, the "thickness" of an object means the thickness of the entire object, and for example, if the object is made up of multiple layers, it means the total thickness of all layers that make up the object. In this specification, unless otherwise specified, the "thickness" of an object refers to the average thickness measured at five randomly selected points on the object, and can be obtained using a constant pressure thickness gauge in accordance with JIS K 7130.

[0018] In this specification, the glass transition temperature (Tg) can be determined by calculation using the Fox formula. For example, the Tg of an acrylic resin can be determined by calculation 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. However, 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.

[0019] In this specification, the term "solid content" or "active ingredient" refers to the components contained in the target composition excluding water and diluting 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] In the drawings, for the sake of convenience, in order to make the features of the present invention easier to understand, the essential parts may be shown enlarged, and the dimensional ratios of each component may not necessarily be the same as in reality.

[0022] [Embodiments of the composite sheet for forming a protective film according to the present embodiment] The composite sheet for forming a protective film of this embodiment is a composite sheet for forming a protective film on the protruding electrode forming surface of a member with protruding electrodes on which protruding electrodes are formed, and includes a base material, an adhesive layer, a metal baked material layer, and a protective film forming layer in this order. In the composite sheet for forming a protective film of this embodiment, the pressure-sensitive adhesive layer and the baked metal material layer are in direct contact with each other, and the baked metal material layer and the protective film-forming layer are in direct contact with each other. In this embodiment, the interface where the adhesive layer and the baked metal material layer are in direct contact is referred to as "interface (X)", and the interface where the baked metal material layer and the protective film forming layer are in direct contact is referred to as "interface (Y)".

[0023] The present inventors conducted extensive research to solve the above-mentioned problems. As a result, they found that a sintered metal material is more compatible with a projecting electrode made of a metallic material than a protective film-forming layer made of a non-metallic material. The present inventors came up with the idea that by utilizing this property, it might be possible to easily form a joint made of a sintered metal material on the top of a projecting electrode. Therefore, the inventors attempted to prepare a composite sheet for forming a protective film having the above-mentioned configuration, attach the protective film forming layer to the protruding electrode forming surface of a member with protruding electrodes on which the protruding electrodes are formed, cause the tops of the protruding electrodes to protrude from the protective film forming layer so as to contact the tops of the protruding electrodes with the metal sintered material layer, and then separate the composite sheet for forming a protective film at the interface (Y). As a result, the following phenomena (1) to (3) were found to occur. (1) The fired metal material layer in contact with the protective film forming layer is easily peeled off from the protective film forming layer when they are separated at the interface (Y). (2) The fired metal material layer in contact with the top of the protruding electrode is not easily peeled off from the top of the protruding electrode when separation occurs at the interface (Y). (3) Due to the phenomena (1) and (2) above, when an attempt is made to separate the layers at the interface (Y), the force applied to the metal sintered material layer causes the metal sintered material layer to fracture, and the metal sintered material layer in contact with the protective film forming layer can be easily peeled off from the protective film forming layer, while the metal sintered material layer in contact with the top of the protruding electrode remains without being peeled off from the top of the protruding electrode. In other words, the inventor discovered that a joint made of a fired metal material can be formed on the top of a projecting electrode by the extremely simple method of separating a composite sheet for forming a protective film at the interface (Y), and thus completed the present invention.

[0024] <Adhesive strength of interface (X) and adhesive strength of interface (Y)> In the composite sheet for forming a protective film of this embodiment, from the viewpoint of facilitating the formation of a joint made of a fired metal material at the top of the protruding electrode due to the phenomena (1) to (3) above, it is preferable that the adhesive strength of the interface (Y) is smaller than the adhesive strength of the interface (X). From the same viewpoint, the ratio of the adhesive strength of interface (X) to the adhesive strength of interface (Y) [adhesive strength of interface (X) / adhesive strength of interface (Y)] is preferably 1.5 or more, more preferably 1.6 or more, and even more preferably 1.7 or more. In addition, the adhesive strength between the metal sintered material layer of the composite sheet for forming a protective film of this embodiment and the protruding electrode is preferably greater than the adhesive strength at the interface (X), from the viewpoint of facilitating the formation of a joint made of metal sintered material at the top of the protruding electrode due to the phenomena (1) to (3) above. The ratio of the adhesive strength between the fired metal material layer and the projecting electrode to the adhesive strength at the interface (X) [adhesive strength between the fired metal material layer and the projecting electrode / adhesive strength at the interface (X)] is preferably greater than 1.0. In the composite sheet for forming a protective film of this embodiment, the adhesive strength at interfaces (between layers) other than interface (X) and interface (Y) is preferably higher than the adhesive strength at interface (Y). Specifically, the adhesive strength between the substrate and the pressure-sensitive adhesive layer is preferably higher than the adhesive strength at interface (Y). Furthermore, when a buffer layer is provided between the substrate and the pressure-sensitive adhesive layer, the adhesive strength between the substrate and the buffer layer and the adhesive strength between the buffer layer and the pressure-sensitive adhesive layer are preferably higher than the adhesive strength at interface (Y). In this specification, the adhesive strength at each interface (between each layer) can be measured by the method described in the examples below.

[0025] Hereinafter, the configuration (layer configuration) of the composite sheet for forming a protective film will be described, and then each layer constituting the composite sheet for forming a protective film will be described in detail.

[0026] <Configuration of composite sheet for forming protective film (layer configuration)> The composite sheet for forming a protective film of this embodiment includes, in this order, a substrate, an adhesive layer, a fired metal material layer, and a protective film-forming layer, and has an interface (X) where the adhesive layer and the fired metal material layer are in direct contact, and an interface (Y) where the fired metal material layer and the protective film-forming layer are in direct contact. The composite sheet for forming a protective film of this embodiment may be formed only from the substrate, the adhesive layer, the burned metal material layer, and the protective film-forming layer, but may also have layers other than these layers, such as a buffer layer, an intermediate release layer, a release film, and an antistatic layer. Hereinafter, a first embodiment and a second embodiment will be described as examples of the layer structure of the composite sheet for forming a protective film of this embodiment.

[0027] (First aspect) A first aspect of the composite sheet for forming a protective film of this embodiment is shown in FIG. The composite sheet 1a for forming a protective film shown in Fig. 1 has a laminated structure in which a substrate 10, a pressure-sensitive adhesive layer 11, a fired metal material layer 12, and a protective film-forming layer 13 are laminated in this order. Although not shown, a release film or the like may be provided on the other surface of the protective film-forming layer 13. Furthermore, another layer may be provided between the substrate 10 and the pressure-sensitive adhesive layer 11.

[0028] (Second aspect) A second aspect of the composite sheet for forming a protective film of this embodiment is shown in FIG. The composite sheet 1b for forming a protective film shown in FIG. 2 has a laminated structure in which a substrate 10, a pressure-sensitive adhesive layer 11, a fired metal material layer 12, and a protective film-forming layer 13 are laminated in this order, and further has a buffer layer 14 between the substrate 10 and the pressure-sensitive adhesive layer 11. Although not shown, a release film or the like may be provided on the other surface of the protective film-forming layer 12. Furthermore, another layer may be provided between the substrate 10 and the buffer layer 14. Furthermore, another layer may be provided between the buffer layer 14 and the pressure-sensitive adhesive layer 11.

[0029] <Base material> The composite sheet for forming a protective film of this embodiment has a substrate. The substrate is in the form of a sheet or film, and examples of the constituent materials thereof include the following 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; and vinyl chloride-based resins (copolymers obtained using vinyl chloride as a monomer) such as polyvinyl chloride and vinyl chloride copolymer. resins obtained by the above method); polystyrene; polycycloolefin; 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 of the above polyesters; poly(meth)acrylic acid esters; polyurethanes; polyurethane acrylates; polyimides; polyamides; polycarbonates; fluororesins; polyacetals; modified polyphenylene oxides; polyphenylene sulfides; polysulfones; polyether ketones; and the like. Further, examples of the resin constituting the substrate include polymer alloys such as mixtures of the above polyesters with other resins. The polymer alloys of the above polyesters with other resins preferably contain a relatively small amount of resin other than polyester. Further, examples of the resin constituting the substrate include crosslinked resins in which one or more of the resins exemplified above are crosslinked; and modified resins such as ionomers using one or more of the resins exemplified above. The resin constituting the substrate may be used alone or in combination of two or more.

[0030] The substrate may be a single layer or a multi-layer substrate of two or more layers. When the substrate is a multi-layer substrate, the multi-layer substrate may be the same or different from one another, and the combination of the multi-layer substrate is not particularly limited.

[0031] The thickness of the substrate is not particularly limited, but is preferably 5 to 1,000 μm, more preferably 10 to 500 μm, even more preferably 15 to 300 μm, and even more preferably 20 to 150 μm.

[0032] The substrate preferably has a high thickness precision, i.e., a thickness variation that is suppressed regardless of location. Among the above-mentioned constituent materials, examples of materials with a high thickness precision that can be used to constitute the substrate include polyethylene, polyolefins other than polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyesters other than polyethylene terephthalate and polybutylene terephthalate, ethylene-vinyl acetate copolymer, etc.

[0033] In addition to the main constituent materials such as the resin, the substrate may contain various known additives such as fillers, colorants, antioxidants, organic lubricants, catalysts, softeners (plasticizers), and antistatic agents.

[0034] The substrate may be transparent or opaque, may be colored as desired, or may have other layers vapor-deposited thereon.

[0035] The substrate can be produced by a known method. For example, a substrate containing a resin can be produced by molding a resin composition containing the resin.

[0036] <Adhesive layer> The composite sheet for forming a protective film of this embodiment has a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer can be formed from, for example, a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive resin. The pressure-sensitive adhesive layer may be a single layer or may be a multi-layer structure of two or more layers. When the pressure-sensitive adhesive layer is a multi-layer structure, these multi-layer structures may be the same or different from each other, and the combination of these multi-layer structures is not particularly limited. The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 3 to 100 μm, more preferably 5 to 50 μm, even more preferably 5 to 30 μm, and still more preferably 5 to 20 μm.

[0037] (Adhesive resin) The adhesive resin may be a polymer that has adhesiveness by itself and has a weight average molecular weight (Mw) of 10,000 or more. The weight average molecular weight (Mw) of the adhesive resin is preferably from 10,000 to 2,000,000, more preferably from 20,000 to 1,500,000, and even more preferably from 30,000 to 1,000,000, from the viewpoint of adjusting the adhesive strength of the adhesive layer.

[0038] Specific examples of adhesive resins include rubber-based resins such as acrylic resins, urethane resins, and polyisobutylene resins, polyester resins, olefin resins, silicone resins, and polyvinyl ether resins. These adhesive resins may be used alone or in combination of two or more. Furthermore, 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.

[0039] In this embodiment, from the viewpoint of ease of adjusting the adhesive strength of the adhesive layer, the adhesive resin preferably contains an acrylic resin.

[0040] The content of the acrylic resin in the adhesive resin is preferably 30 to 100 mass%, more preferably 50 to 100 mass%, even more preferably 70 to 100 mass%, and still more preferably 85 to 100 mass%, relative to the total amount (100 mass%) of the adhesive resin contained in the adhesive composition or adhesive layer.

[0041] In this embodiment, examples of acrylic resins that can be used as adhesive resins include polymers containing structural units derived from alkyl (meth)acrylates having a linear or branched alkyl group, and polymers containing structural units derived from (meth)acrylates having a cyclic structure.

[0042] The weight average molecular weight (Mw) of the acrylic resin is preferably 100,000 to 1,500,000, more preferably 200,000 to 1,300,000, even more preferably 350,000 to 1,200,000, and still more preferably 500,000 to 1,100,000.

[0043] The acrylic resin used in this embodiment is more preferably an acrylic copolymer (A1) having a structural unit (a1) derived from an alkyl (meth)acrylate (a1′) (hereinafter also referred to as “monomer (a1′)”) and a structural unit (a2) derived from a functional group-containing monomer (a2′) (hereinafter also referred to as “monomer (a2′)”).

[0044] The number of carbon atoms in the alkyl group of the monomer (a1') is preferably 1 to 24, more preferably 1 to 12, even more preferably 2 to 10, and still more preferably 4 to 8, from the viewpoint of imparting excellent adhesive strength to the adhesive layer. The alkyl group contained in the monomer (a1') may be a linear alkyl group or a branched alkyl group.

[0045] Examples of the monomer (a1') include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, iso-butyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, and stearyl (meth)acrylate. These monomers (a1') may be used alone or in combination of two or more. As the monomer (a1'), n-butyl acrylate and 2-ethylhexyl acrylate are preferred, and n-butyl acrylate is more preferred.

[0046] The content of the structural unit (a1) is preferably 50 to 99.9 mass%, more preferably 60 to 99.0 mass%, even more preferably 70 to 97.0 mass%, and still more preferably 80 to 95.0 mass%, based on all structural units (100 mass%) of the acrylic copolymer (A1).

[0047] Examples of the functional group contained in the monomer (a2') include a hydroxyl group, a carboxyl group, an amino group, and an epoxy group. That is, examples of the monomer (a2') include hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, and epoxy group-containing monomers. These monomers (a2') may be used alone or in combination of two or more. Among these, as the monomer (a2'), hydroxyl group-containing monomers and carboxy group-containing monomers are preferred, and carboxy group-containing monomers are more preferred.

[0048] Examples of hydroxyl group-containing monomers include hydroxyalkyl (meth)acrylates such as 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 hydroxyl group-containing compounds such as unsaturated alcohols such as vinyl alcohol and allyl alcohol.

[0049] Examples of carboxy group-containing monomers include ethylenically unsaturated monocarboxylic acids such as (meth)acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid and citraconic acid and their anhydrides; 2-(acryloyloxy)ethyl succinate; and 2-carboxyethyl (meth)acrylate.

[0050] The content of the structural unit (a2) is preferably 0.1 to 30 mass%, more preferably 0.5 to 20 mass%, even more preferably 1.0 to 15 mass%, and even more preferably 3.0 to 10 mass%, based on all structural units (100 mass%) of the acrylic copolymer (A1).

[0051] The acrylic copolymer (A1) may further contain a structural unit (a3) ​​derived from a monomer (a3') other than the monomers (a1') and (a2'). In the acrylic copolymer (A1), the total content of the structural units (a1) and (a2) is preferably 70 to 100 mass%, more preferably 80 to 100 mass%, even more preferably 90 to 100 mass%, and still more preferably 95 to 100 mass%, based on all structural units (100 mass%) of the acrylic copolymer (A1).

[0052] Examples of the monomer (a3') include olefins such as ethylene, propylene, and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; diene monomers such as butadiene, isoprene, and chloroprene; (meth)acrylates having a cyclic structure such as cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and imide (meth)acrylate; styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, (meth)acrylamide, (meth)acrylonitrile, (meth)acryloylmorpholine, and N-vinylpyrrolidone.

[0053] The content of the adhesive resin in the adhesive composition is preferably 35 to 100 mass%, more preferably 50 to 100 mass%, even more preferably 60 to 100 mass%, and still more preferably 70 to 99.5 mass%, relative to the total amount (100 mass%) of the active ingredients of the adhesive composition.

[0054] (Crosslinking agent) In the present embodiment, when the pressure-sensitive adhesive composition contains a pressure-sensitive adhesive resin having a functional group, such as the above-mentioned acrylic copolymer (A1), it is preferable that the pressure-sensitive adhesive composition further contains a crosslinking agent. The crosslinking agent reacts with the adhesive resin having a functional group, and crosslinks the adhesive resins together using the functional group as the crosslinking starting point.

[0055] Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an aziridine-based crosslinking agent, and a metal chelate-based crosslinking agent. These crosslinking agents may be used alone or in combination of two or more. Among these crosslinking agents, isocyanate-based crosslinking agents are preferred from the viewpoints of increasing cohesive strength and improving adhesive strength, and of ease of availability. Examples of the isocyanate crosslinking agent include polyvalent isocyanate compounds such as aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; alicyclic polyisocyanates such as dicyclohexylmethane-4,4'-diisocyanate, bicycloheptane triisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, methylenebis(cyclohexylisocyanate), 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, and hydrogenated xylylene diisocyanate; and acyclic aliphatic polyisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate. Further, examples of the isocyanate crosslinking agent include a trimethylolpropane adduct modified product of the polyisocyanate compound, a biuret modified product obtained by reacting the polyisocyanate compound with water, and an isocyanurate modified product containing an isocyanurate ring. Among these, from the viewpoint of suppressing a decrease in the elastic modulus of the pressure-sensitive adhesive layer during heating and suppressing adhesion of residues derived from the pressure-sensitive adhesive layer to the adherend, it is preferable to use a trimethylolpropane adduct-type modified polyisocyanate compound, it is more preferable to use a trimethylolpropane adduct-type modified aromatic polyisocyanate compound, and it is even more preferable to use a trimethylolpropane adduct-type modified tolylene diisocyanate.

[0056] The content of the crosslinking agent is adjusted appropriately depending on the number of functional groups possessed by the adhesive resin, but is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 5 parts by mass per 100 parts by mass of the adhesive resin having functional groups.

[0057] (tackifier) In the present embodiment, the pressure-sensitive adhesive composition may further contain a tackifier from the viewpoint of further improving adhesive strength. In this specification, the term "tackifier" refers to a component that auxiliary improves the adhesive strength of an adhesive resin, and has a weight average molecular weight (Mw) of less than 10,000, and is distinguished from the adhesive resin described above. The weight average molecular weight (Mw) of the tackifier is less than 10,000, preferably 400 to 9,000, more preferably 500 to 8,000, and even more preferably 800 to 5,000.

[0058] Examples of tackifiers include rosin resins, terpene resins, styrene resins, C5 petroleum resins obtained by copolymerizing C5 fractions such as pentene, isoprene, piperine, and 1,3-pentadiene produced by thermal decomposition of petroleum naphtha, C9 petroleum resins obtained by copolymerizing C9 fractions such as indene and vinyltoluene produced by thermal decomposition of petroleum naphtha, and hydrogenated resins obtained by hydrogenating these.

[0059] The softening point of the tackifier is preferably 60 to 170°C, more preferably 65 to 160°C, and even more preferably 70 to 150°C. In this specification, the "softening point" of a tackifier means a value measured in accordance with JIS K 2531. The tackifier may be used alone or in combination with two or more types that differ in softening point, structure, etc. When two or more types of tackifiers are used, it is preferable that the weighted average of the softening points of the multiple tackifiers falls within the above range.

[0060] The content of the tackifier is preferably 0.01 to 65 mass%, more preferably 0.1 to 50 mass%, even more preferably 1 to 40 mass%, and even more preferably 2 to 30 mass%, relative to the total amount (100 mass%) of the active ingredients in the pressure-sensitive adhesive composition.

[0061] (adhesive additives) In this embodiment, the pressure-sensitive adhesive composition may contain, in addition to the additives described above, pressure-sensitive adhesive additives used in general pressure-sensitive adhesives, as long as the effects of the present invention are not impaired. Examples of such adhesive additives include antioxidants, softeners (plasticizers), rust inhibitors, pigments, dyes, retarders, reaction accelerators (catalysts), ultraviolet absorbers, energy ray-curable compounds and photopolymerization initiators, which will be described later. These adhesive additives may be used alone or in combination of two or more.

[0062] When these adhesive additives are contained, the content of each adhesive additive is preferably 0.0001 to 20 parts by mass, more preferably 0.001 to 10 parts by mass, based on 100 parts by mass of the adhesive resin.

[0063] <Metal fired material layer> The composite sheet for forming a protective film of this embodiment has a fired metal material layer. The metal sintered material layer is formed from a film-like sintered material. The film-shaped sintered material preferably contains a polymer of alkyl methacrylate having 9 to 13 carbon atoms, and more preferably contains sinterable metal particles and a binder component, wherein the binder component contains a copolymer of alkyl methacrylate having 8 or less carbon atoms and alkyl methacrylate having 9 to 13 carbon atoms. The film-shaped sintered material may consist of one layer (single layer), or may consist of two or more layers. When the film-shaped sintered material consists of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited as long as it does not impair the effects of the present invention. In this specification, not only in the case of film-shaped fired materials, "multiple layers may be the same or different" means "all layers may be the same, all layers may be different, or only some layers may be the same", and further "multiple layers are different" means "at least one of the constituent materials, the composition ratio of the constituent materials, and the thickness of each layer is different".

[0064] The thickness of the metal sintered material layer (thickness before sintering) is not particularly limited, but from the viewpoint of making it easy to cleave the metal sintered material layer when separating the composite sheet for forming a protective film at the interface (Y) and making it easy to leave the metal sintered material on the top of the projecting electrode, it is preferably less than 100 μm, more preferably 60 μm or less, even more preferably 40 μm or less, and even more preferably 20 μm or less. Also, from the viewpoint of formability of the metal sintered material layer, it is preferably 5 μm or more.

[0065] (Sinterable metal particles) Sinterable metal particles are metal particles that can be fused and bonded to form a sintered body by heat treatment at a temperature above the melting point of the metal particles when firing a film-shaped sintered material. By forming a sintered body, it is possible to sinter-bond the film-shaped sintered material with an article that is sintered in contact with it. Specifically, it is possible to sinter-bond a chip and a substrate via the film-shaped sintered material.

[0066] Examples of materials constituting the sinterable metal particles include elemental metals, barium titanate, oxides and alloys of the elemental metals. Examples of the elemental metals include silver, gold, copper, iron, nickel, aluminum, silicon, palladium, platinum, and titanium. Preferred materials for the sinterable metal particles are silver and silver oxide. Only one type of sinterable metal particle may be blended, or two or more types may be blended in combination.

[0067] The sinterable metal particles are preferably silver nanoparticles, which are nano-sized silver particles.

[0068] The particle size of the sinterable metal particles contained in the film-shaped sintered material is not particularly limited as long as it can exhibit the above-mentioned sinterability, but it may be 100 nm or less, 50 nm or less, or 30 nm or less. Note that the particle size of the metal particles contained in the film-shaped sintered material is the diameter of the projected area circle equivalent of the particle size of the metal particles observed with an electron microscope. Metal particles within the above particle size range are preferred because they have excellent sinterability. The particle size of the sinterable metal particles contained in the film-shaped sintered material may be 0.1 to 95 nm, 0.3 to 50 nm, or 0.5 to 30 nm, as determined by observing the particle size of metal particles with a projected area circle equivalent diameter of 100 nm or less under an electron microscope. Note that the number of metal particles to be measured is 100 or more randomly selected per film-shaped sintered material.

[0069] In addition to metal particles (sinterable metal particles) having a particle diameter of 100 nm or less, the film-shaped sintered material may further contain non-sinterable metal particles having a particle diameter exceeding 100 nm that do not fall into this category. The particle diameter of the non-sinterable metal particles having a particle diameter exceeding 100 nm may be a number average particle diameter of more than 150 nm and not more than 50,000 nm, 150 to 10,000 nm, or 180 to 5,000 nm, as determined for metal particles having a projected area circle equivalent diameter exceeding 100 nm as observed with an electron microscope.

[0070] The content of metal particles having a particle diameter (diameter of a circle equivalent to a projected area) of more than 300 nm relative to the total mass (100% by mass) of all metal particles is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more. The upper limit of this content may be, for example, 90% by mass or less, 85% by mass or less, or 80% by mass or less. As an example of the range of the above numerical value, the content of metal particles having the above particle diameter (diameter equivalent to a circle having a projected area) of more than 300 nm relative to the total mass (100 mass%) of all metal particles may be 10 to 90 mass%, 15 to 85 mass%, or 20 to 80 mass%.

[0071] Examples of metal species for non-sinterable metal particles having a particle size of more than 100 nm include the same metal species as those exemplified above for the sinterable metal particles, with silver, copper, and oxides of these being preferred. The metal particles having a particle size of 100 nm or less and the non-sinterable metal particles having a particle size of more than 100 nm may be the same metal species or different metal species. For example, the metal particles having a particle size of 100 nm or less may be silver particles, and the non-sinterable metal particles having a particle size of more than 100 nm may be silver or silver oxide particles. For example, the metal particles having a particle size of 100 nm or less may be silver or silver oxide particles, and the non-sinterable metal particles having a particle size of more than 100 nm may be copper or copper oxide particles.

[0072] In the film-shaped sintered material, the content of sinterable metal particles relative to the total mass (100 mass%) of all metal particles may be 10 mass% or more, 10 to 90 mass%, or 20 to 85 mass%.

[0073] The surfaces of the sinterable metal particles and / or the non-sinterable metal particles may be coated with an organic material, which improves compatibility with the binder component, prevents aggregation of particles, and allows for uniform dispersion. When the surfaces of sinterable metal particles and / or non-sinterable metal particles are coated with an organic substance, the mass and particle diameter of the sinterable metal particles and non-sinterable metal particles include the coating.

[0074] (binder component) The addition of a binder component allows the fired material to be formed into a film and provides adhesiveness to the fired film material before firing. The resin constituting the binder component (hereinafter sometimes referred to as "binder resin") may be thermally decomposable, so that it is thermally decomposed by heat treatment during firing of the fired film material.

[0075] From the viewpoint of easily adjusting the adhesive strength of the film-shaped sintered material to an appropriate level, the binder resin preferably contains a polymer of alkyl methacrylate having 9 to 13 carbon atoms, and more preferably contains a copolymer of alkyl methacrylate having 8 or less carbon atoms and alkyl methacrylate having 9 to 13 carbon atoms. Homopolymers of alkyl methacrylate having 8 or less carbon atoms have a relatively high glass transition temperature (Tg) of approximately -10°C to 110°C. Homopolymers of alkyl methacrylate having 9 to 13 carbon atoms have a relatively low glass transition temperature (Tg) of approximately -80°C to -10°C. When the binder resin contains a copolymer of alkyl methacrylate having 8 or less carbon atoms, which has a relatively high homopolymer glass transition temperature (Tg), and alkyl methacrylate having 9 to 13 carbon atoms, which has a relatively low homopolymer glass transition temperature (Tg), the adhesive strength of the film-shaped sintered material can be more easily adjusted to an appropriate level. Furthermore, since the binder component contains a structural unit derived from methacrylate, it can be fired at a relatively low temperature, and the conditions for obtaining sufficient adhesive strength after sintering can be easily met.

[0076] In this specification, "room temperature" means a temperature that is neither particularly cold nor hot, that is, an ordinary temperature, and examples thereof include temperatures of 15 to 25°C.

[0077] As the alkyl methacrylate having 8 or less carbon atoms, from the viewpoint of easily adjusting the adhesive strength of the film-shaped baked material to an appropriate level when combined with an alkyl methacrylate having 9 to 13 carbon atoms, alkyl methacrylates having 2 to 8 carbon atoms are preferred, alkyl methacrylates having 3 to 8 carbon atoms are more preferred, alkyl methacrylates having 4 to 8 carbon atoms are even more preferred, and branched alkyl methacrylates having 6 to 8 carbon atoms are particularly preferred. As the alkyl methacrylate having 9 to 13 carbon atoms, from the viewpoint of easily adjusting the adhesive strength of the film-shaped baked material to an appropriate level when combined with an alkyl methacrylate having 8 or less carbon atoms, alkyl methacrylates having 9 to 12 carbon atoms are preferred, and alkyl methacrylates having 10 to 12 carbon atoms are more preferred.

[0078] Specific examples of alkyl methacrylates having 8 or less carbon atoms include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, pentyl methacrylate, isopentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, isooctyl methacrylate, and 2-ethylhexyl methacrylate. Specific examples of alkyl methacrylates having 9 to 13 carbon atoms include nonyl methacrylate, decyl methacrylate, isodecyl methacrylate, undecyl methacrylate, dodecyl methacrylate, lauryl methacrylate, stearyl methacrylate, and isostearyl methacrylate.

[0079] The binder resin may contain a polymer compound derived from a (meth)acrylate compound that does not fall under the copolymer of the alkyl methacrylate having 8 or less carbon atoms and the alkyl methacrylate having 9 to 13 carbon atoms. "Derived from" here means that the monomer has undergone the structural changes necessary for polymerization.

[0080] The polymer or copolymer may contain a structural unit derived from another copolymerizable monomer that does not fall under the category of alkyl methacrylate having 13 or less carbon atoms. The other copolymerizable monomer is not particularly limited as long as it is a compound copolymerizable with the (meth)acrylate compound, and examples thereof include unsaturated carboxylic acids such as alkyl methacrylates, alkyl acrylates, (meth)acrylic acid, vinyl benzoic acid, maleic acid, and vinyl phthalic acid having 14 or more carbon atoms; and vinyl group-containing radically polymerizable compounds such as vinylbenzyl methyl ether, vinyl glycidyl ether, styrene, α-methylstyrene, butadiene, and isoprene.

[0081] The glass transition temperature (Tg) of the polymer or copolymer serving as the binder resin can be calculated using the Fox equation described above and may be between -80°C and -15°C, preferably between -65°C and -15°C, more preferably between -60°C and -20°C, and even more preferably between -55°C and -25°C. Having the Tg of the copolymer calculated using the Fox equation below the upper limit is preferable because, after forming the film-shaped sintered material with a support sheet, it can be attached to a semiconductor wafer at room temperature without heating. On the other hand, having the Tg of the copolymer calculated using the Fox equation above the lower limit makes it easier to maintain the shape of the film-shaped sintered material.

[0082] In addition, alkyl (meth)acrylates generally exhibit the following behavior regarding the glass transition temperature (Tg). That is, when a homopolymer of an alkyl (meth)acrylate compound is formed, the longer the alkyl group of the alkyl (meth)acrylate, the lower the glass transition temperature (Tg). Furthermore, when the alkyl group length is the same, the glass transition temperature (Tg) of a homopolymer of an alkyl acrylate compound tends to be lower than the glass transition temperature (Tg) of a homopolymer of an alkyl methacrylate compound. The glass transition temperature (Tg) of a copolymer of two or more alkyl (meth)acrylate compounds can be appropriately adjusted by adjusting the respective content ratios of the structural units derived from the alkyl (meth)acrylate compound in the copolymer.

[0083] The desired glass transition temperature (Tg) of the copolymer of the binder resin can be obtained by using a polymer of alkyl methacrylate having 9 to 13 carbon atoms and adjusting the copolymerization ratio of the alkyl methacrylate having 8 or less carbon atoms to the alkyl methacrylate having 9 or more and 13 carbon atoms. The copolymerization ratio (mass ratio of each monomer) of the alkyl methacrylate having 8 or less carbon atoms to the alkyl methacrylate having 9 or more and 13 carbon atoms is preferably 5 / 95 to 95 / 5, more preferably 10 / 90 to 90 / 10, still more preferably 20 / 80 to 80 / 20, and particularly preferably 30 / 70 to 70 / 30.

[0084] The weight-average molecular weight (Mw) of the binder resin is preferably 100,000 to 1,000,000, more preferably 150,000 to 800,000, and even more preferably 200,000 to 600,000. When the weight-average molecular weight of the resin is within the above range, the film exhibits sufficient strength and is easily imparted with flexibility.

[0085] In the binder resin, the content of the polymer of alkyl methacrylate having 9 to 13 carbon atoms, or the content of the copolymer of alkyl methacrylate having 8 or less carbon atoms and alkyl methacrylate having 9 to 13 carbon atoms, relative to the total mass (100 mass%) of the binder components, is preferably 50 to 100 mass%, more preferably 80 to 100 mass%, even more preferably 90 to 100 mass%, even more preferably 95 to 100 mass%, and may be 100 mass%.

[0086] The polymer or copolymer may contain structural units derived from other copolymerizable monomers that are not alkyl methacrylates having 13 or fewer carbon atoms. The content of the structural units derived from alkyl methacrylates having 13 or fewer carbon atoms is preferably 90 to 100% by mass, more preferably 95 to 100% by mass, and even more preferably 98 to 100% by mass, relative to the total mass (100% by mass) of the structural units of the copolymer, and may be 100% by mass.

[0087] In the binder resin, the content of the (meth)acrylate-derived structural unit relative to the total mass (100 mass%) of the structural units of the binder resin is preferably 50 to 100 mass%, more preferably 80 to 100 mass%, even more preferably 90 to 100 mass%, even more preferably 95 to 100 mass%, and may be 100 mass%.

[0088] The binder component may be thermally decomposable, being thermally decomposed by heat treatment as the firing of the film-shaped fired material. The thermal decomposition of the binder component can be confirmed by the mass reduction of the binder component due to firing. Note that the components blended as the binder component may be almost thermally decomposed by firing, but the entire mass of the components blended as the binder component may not be thermally decomposed by firing. The binder component may be one whose mass after firing is 10% by mass or less, 5% by mass or less, or 3% by mass or less of the total mass (100% by mass) of the binder component before firing.

[0089] Furthermore, copolymers or homopolymers containing a large amount of structural units derived from alkyl methacrylate compounds have better thermal decomposition properties when formed into a film-shaped fired material than copolymers or homopolymers containing a large amount of structural units derived from alkyl acrylate compounds. Therefore, the content of structural units derived from alkyl methacrylate compounds is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass, even more preferably 95 to 100% by mass, and may be 100% by mass, relative to the total mass (100% by mass) of the structural units of the binder resin.

[0090] In addition to the above-mentioned sinterable metal particles, non-sinterable metal particles, and binder components, the film-shaped sintered material may also contain other additives that do not fall under the category of sinterable metal particles, non-sinterable metal particles, and binder components, within a range that does not impair the effects of the present invention.

[0091] Other additives that may be contained in the film-shaped sintered material include, for example, solvents, dispersants, plasticizers, tackifiers, storage stabilizers, antifoaming agents, thermal decomposition accelerators, and antioxidants. Only one type of additive may be contained, or two or more types may be contained. These additives are not particularly limited, and can be appropriately selected from those commonly used in this field.

[0092] The binder component is preferably thermally decomposed by heat treatment during firing of the film-shaped fired material. Therefore, the content of thermosetting resin such as epoxy resin is preferably 10% by mass or less, more preferably 5% by mass or less, relative to 100% by mass of the binder component, and even more preferably substantially no thermosetting resin is contained. From the same viewpoint, the content of acrylate-derived structural units from "acrylate" and "methacrylate" relative to the total mass (100 mass%) of the structural units of the binder resin is preferably 10 mass% or less, more preferably 5 mass% or less, and even more preferably is substantially free of acrylate-derived structural units.

[0093] (Composition of film-shaped fired material) The film-shaped sintered material may be composed of sinterable metal particles, a binder component, and other additives, and the sum of their contents (mass%) may be 100 mass%. When the film-shaped sintered material contains non-sinterable metal particles, the film-shaped sintered material may be composed of sinterable metal particles, non-sinterable metal particles, a binder component, and other additives, and the sum of their contents (mass%) may be 100 mass%.

[0094] In the film-shaped sintered material, the content of sinterable metal particles relative to the total mass (100 mass%) of all components other than the solvent (hereinafter referred to as "solids") is preferably 15 to 88 mass%, more preferably 15 to 85 mass%, and even more preferably 20 to 80 mass%. When the content of sinterable metal particles is equal to or less than the above upper limit, the content of the binder component can be sufficiently ensured, making it easier to maintain the film shape. On the other hand, when the content of sinterable metal particles is equal to or greater than the above lower limit, sinterable metal particles or sinterable metal particles and non-sinterable metal particles fuse together during sintering, resulting in the effect of exhibiting high bonding strength (shear adhesive strength) after sintering.

[0095] When the film-shaped sintered material contains non-sinterable metal particles, the total content of sinterable metal particles and non-sinterable metal particles relative to the total mass (100 mass%) of the solid content in the film-shaped sintered material is preferably 50 to 98 mass%, more preferably 70 to 95 mass%, and even more preferably 80 to 95 mass%.

[0096] The content of the binder component relative to the total mass (100 mass%) of the solid content in the film-shaped sintered material is preferably 2 to 50 mass%, more preferably 5 to 30 mass%, and even more preferably 5 to 20 mass%. When the content of the binder component is equal to or less than the above upper limit, the content of the sinterable metal particles can be sufficiently ensured, thereby further improving the bonding and adhesive strength between the film-shaped sintered material and the adherend. On the other hand, when the content of the binder component is equal to or more than the above lower limit, it becomes easier to maintain the film shape.

[0097] In the film-shaped sintered material, the mass ratio of the sinterable metal particles to the binder component (sinterable metal particles:binder component) is preferably 50:1 to 1:5, more preferably 20:1 to 1:2, and even more preferably 10:1 to 1:1. When the film-shaped sintered material contains non-sinterable metal particles, the mass ratio of the sinterable metal particles and non-sinterable metal particles to the binder component ((sinterable metal particles + non-sinterable metal particles):binder component) is preferably 50:1 to 1:1, more preferably 20:1 to 2:1, and even more preferably 9:1 to 4:1.

[0098] (Release film) The film-shaped sintered material can be formed with a release film laminated thereon. When in use, the release film is peeled off and the film-shaped sintered material is placed on the object to be sinter-bonded. The release film also functions as a protective film to prevent damage to the film-shaped sintered material and adhesion of dirt. The release film needs to be provided on at least one side of the film-shaped sintered material, and may be provided on both sides of the film-shaped sintered material.

[0099] The thickness of the release film is usually about 10 to 500 μm, preferably about 15 to 300 μm, and particularly preferably about 20 to 250 μm.

[0100] (Method for producing film-shaped fired material) The film-shaped fired material can be formed using a fired material composition containing the constituent materials. For example, a firing material composition containing the components and solvent for constituting the film-shaped fired material can be coated or printed onto the surface on which the film-shaped fired material is to be formed, and the solvent can be evaporated as necessary to form the film-shaped fired material in the desired location. The surface on which the film-shaped fired material is formed can be the surface of a release film.

[0101] When applying the fired material composition, the solvent preferably has a boiling point of less than 200°C, such as n-hexane (boiling point: 68°C), ethyl acetate (boiling point: 77°C), 2-butanone (boiling point: 80°C), n-heptane (boiling point: 98°C), methylcyclohexane (boiling point: 101°C), toluene (boiling point: 111°C), acetylacetone (boiling point: 138°C), n-xylene (boiling point: 139°C), and dimethylformamide (boiling point: 153°C). These may be used alone or in combination.

[0102] The baking material composition may be applied by a known method, for example, a method using various coaters such as an air knife coater, a blade coater, a bar coater, a gravure coater, a Comma Coater (registered trademark), a roll coater, a roll knife coater, a curtain coater, a die coater, a knife coater, a screen coater, a Mayer bar coater, or a kiss coater.

[0103] When printing the sintered material composition, the solvent may be any solvent that can be evaporated and dried after printing, and preferably has a boiling point of 65 to 350° C. Examples of such solvents include the solvents with boiling points of less than 200° C. listed above, as well as isophorone (boiling point: 215° C.), butyl carbitol (boiling point: 230° C.), 1-decanol (boiling point: 233° C.), butyl carbitol acetate (boiling point: 247° C.), and isobornyl cyclohexanol (boiling point: 318° C.). If the boiling point exceeds 350°C, the solvent will be difficult to volatilize during evaporative drying after printing, making it difficult to obtain the desired shape, and the solvent may remain in the film during baking, potentially degrading bonding and adhesion. If the boiling point is below 65°C, the solvent will volatilize during printing, potentially compromising thickness stability. Using a solvent with a boiling point of 200 to 350°C can suppress the increase in viscosity due to solvent volatilization during printing, ensuring printability.

[0104] The firing material composition can be printed by a known printing method, but is preferably printed by a screen printing method such as silk screen printing or rotary screen printing.

[0105] The shape of the film-shaped sintered material may be appropriately set to match the shape of the object to be sintered and bonded, and is preferably circular or rectangular. A circular shape corresponds to the shape of a semiconductor wafer. A rectangular shape corresponds to the shape of a chip. The corresponding shape may be the same as or approximately the same as the shape of the object to be sintered and bonded. When the film-shaped baking material is circular, the area of ​​the circle is 3.5 to 1,600 cm 2 may be 85 to 1,400 cm 2 When the film-shaped fired material is rectangular, the area of ​​the rectangle may be 0.01 to 25 cm 2 may be 0.25 to 9 cm 2 It may be. In particular, if the fired material composition is printed, it is easy to form a film-shaped fired material in a desired shape.

[0106] The drying conditions for the fired material composition are not particularly limited. However, when the fired material composition contains a solvent, it is preferable to heat-dry it. In this case, it is preferable to dry it at a temperature of, for example, 70 to 250°C, e.g., 80 to 180°C, for 10 seconds to 10 minutes.

[0107] <Protective film forming layer> The protective film forming layer is used to form a protective film on the surface of the member with protruding electrodes on which the protruding electrodes are formed. The protective film-forming layer is soft and has high conformability to uneven surfaces such as the bump-forming surface of a member with protruding electrodes. Furthermore, as will be described later, by adjusting the storage modulus (G') at 80°C and the loss tangent (tanδ) at 80°C of the buffer layer to fall within specific ranges, the protective film-forming layer exhibits excellent protruding electrode penetration and protruding electrode embedding properties. The protective film forming layer may be non-curable or curable, but is preferably curable from the viewpoint of improving the protection of the projecting electrode forming surface (particularly the protection of the projecting electrode base) and from the viewpoint of forming a protective film with excellent protection capabilities such as impact resistance. The protective film forming layer may be a thermosetting layer that is cured by heating, or an energy ray curable layer that is cured by irradiation with energy rays.

[0108] The protective film-forming layer may be a single layer or may be a plurality of layers, such as two or more layers. When the protective film-forming layer is a plurality of layers, these layers may be the same or different from each other, and the combination of these layers is not particularly limited.

[0109] The thickness of the protective film-forming layer is not particularly limited, but is preferably 10 to 70 μm, more preferably 15 to 60 μm, and even more preferably 15 to 45 μm. When the thickness of the protective film-forming layer is equal to or greater than the lower limit, it is easy to produce a sheet with high in-plane uniformity, and it tends to be possible to form a protective film with higher protective ability. Also, when the thickness of the protective film-forming layer is equal to or less than the upper limit, it is possible to prevent the protective film from becoming excessively thick, and it is easy to improve bump penetration properties. The thickness of the protective film forming layer can be adjusted based on the relationship between the thickness of the protective film forming layer and the thickness of the protective film formed by hardening the protective film forming layer, and information such as the height of the bumps on the bumped component to be used. The curable resin film (x) as the protective film-forming layer will be described in detail below.

[0110] (Curable resin film (x)) The curable resin film (x) may be non-curable or curable, but is preferably curable from the viewpoint of improving the protection of the bump formation surface (particularly, the protection of the bump neck) and from the viewpoint of forming a protective film with high protection ability, such as excellent impact resistance. The curable resin film (x) may be a thermosetting resin that is cured by heating, or an energy ray curable resin that is cured by irradiation with energy rays. The thermosetting resin film (x1) and the energy ray-curable resin film (x2) will be described below.

[0111] (Thermosetting resin film (x1)) The thermosetting resin film (x1) of this embodiment forms a cured resin film by being cured by heating. The thermosetting resin film of this embodiment contains a polymer component (A) and a thermosetting component (B). The thermosetting resin film (x1) of this embodiment is formed, for example, from a thermosetting resin composition (x1-1) containing the polymer component (A) and the thermosetting component (B). The polymer component (A) is a component that can be considered to be formed by a polymerization reaction of a polymerizable compound. The thermosetting component (B) is a component that can undergo a curing (polymerization) reaction when triggered by heat. The curing (polymerization) reaction also includes a polycondensation reaction.

[0112] -Polymer component (A)- The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) contain a polymer component (A). The polymer component (A) is a polymer compound for imparting film-forming properties, flexibility, etc. to the thermosetting resin film (x1). The polymer component (A) may be used alone or in combination of two or more. When two or more polymer components (A) are used in combination, the combination and ratio thereof can be selected arbitrarily.

[0113] Examples of the polymer component (A) include acrylic resins, polyarylate resins, polyvinyl acetal, polyesters, urethane resins (resins having urethane bonds), acrylic urethane resins, silicone resins (resins having siloxane bonds), rubber resins (resins having a rubber structure), phenoxy resins, and thermosetting polyimides. Among these, acrylic resins, polyarylate resins, and polyvinyl acetals are preferred.

[0114] Examples of the acrylic resin include known acrylic polymers. The weight average molecular weight (Mw) of the acrylic resin is preferably 10,000 to 2,000,000, more preferably 300,000 to 1,500,000, and even more preferably 500,000 to 1,000,000. When the weight-average molecular weight of the acrylic resin is equal to or greater than the lower limit, the shape stability (stability over time during storage) of the thermosetting resin film (x1) is easily improved. Furthermore, when the weight-average molecular weight of the acrylic resin is equal to or less than the upper limit, the thermosetting resin film (x1) is easily conformable to the irregular surface of the adherend, which makes it easier to suppress the occurrence of voids between the adherend and the thermosetting resin film, for example. Therefore, the coverage of the surface on which the projecting electrodes are formed is improved, and the embedding of grooves is also easily improved.

[0115] The glass transition temperature (Tg) of the acrylic resin is preferably -60 to 70°C, more preferably -40 to 50°C, and even more preferably -30 to 30°C, from the viewpoint of the application and handling properties of the thermosetting resin film (x1).

[0116] Examples of acrylic resins include polymers of one or more (meth)acrylic acid esters; copolymers of two or more monomers selected from (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, and N-methylolacrylamide.

[0117] Examples of the (meth)acrylic acid ester constituting the acrylic resin include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, and (meth) (meth)acrylic acid alkyl esters in which the alkyl group constituting the alkyl ester has a chain structure and has 1 to 18 carbon atoms, such as isononyl acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate (myristyl (meth)acrylate), pentadecyl (meth)acrylate, hexadecyl (meth)acrylate (palmityl (meth)acrylate), heptadecyl (meth)acrylate, and octadecyl (meth)acrylate (stearyl (meth)acrylate); (meth)acrylic acid cycloalkyl esters such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate; (Meth)acrylic acid aralkyl esters such as benzyl (meth)acrylate; (Meth)acrylic acid cycloalkenyl esters such as (meth)acrylic acid dicyclopentenyl ester; (Meth)acrylic acid cycloalkenyloxyalkyl esters such as (meth)acrylic acid dicyclopentenyloxyethyl ester; (Meth)acrylic acid imide; glycidyl group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate; hydroxyl group-containing (meth)acrylic acid esters 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; Examples include substituted amino group-containing (meth)acrylic acid esters such as N-methylaminoethyl (meth)acrylate. As used herein, the term "substituted amino group" refers to a group in which one or two hydrogen atoms of an amino group have been substituted with a group other than a hydrogen atom. Among these, from the viewpoint of the film-forming properties of the thermosetting resin film (x1) and the adhesiveness of the thermosetting resin film (x1) to the protective film-forming surface of a semiconductor chip, it is preferable that the alkyl group constituting the alkyl ester is a copolymer of a (meth)acrylic acid alkyl ester, a glycidyl group-containing (meth)acrylic acid ester, and a hydroxyl group-containing (meth)acrylic acid ester, each of which has a chain structure containing 1 to 18 carbon atoms; it is more preferable that the alkyl group constituting the alkyl ester is a copolymer of a (meth)acrylic acid alkyl ester, a glycidyl group-containing (meth)acrylic acid ester, and a hydroxyl group-containing (meth)acrylic acid ester, each of which has a chain structure containing 1 to 4 carbon atoms; and it is even more preferable that the copolymer is a copolymer of a combination of butyl acrylate, methyl acrylate, glycidyl acrylate, and 2-hydroxyethyl acrylate.

[0118] The acrylic resin may be, for example, a copolymer of one or more monomers selected from (meth)acrylic acid ester, (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, N-methylolacrylamide, and the like.

[0119] The monomers constituting the acrylic resin may be used alone or in combination of two or more. When the acrylic resin is composed of two or more monomers, the combination and ratio thereof can be selected arbitrarily.

[0120] The polyarylate resin in the polymer component (A) may be any known resin, such as a resin having a basic structure obtained by polycondensation of a dihydric phenol with a dibasic acid such as phthalic acid or carboxylic acid. Among these, a polycondensate of bisphenol A with phthalic acid, poly(4,4'-isopropylidenediphenylene terephthalate / isophthalate) copolymer, or a derivative thereof is preferred.

[0121] The polyvinyl acetal in the polymer component (A) may be any known polyvinyl acetal. Among these, preferred polyvinyl acetals include, for example, polyvinyl formal and polyvinyl butyral, with polyvinyl butyral being more preferred. Examples of polyvinyl butyral include those having structural units represented by the following formulas (i)-1, (i)-2, and (i)-3.

[0122] [ka]

[0123] (In the formula, l, m, and n each independently represent an integer of 1 or more.)

[0124] The weight-average molecular weight (Mw) of the polyvinyl acetal is preferably 5,000 to 200,000, more preferably 8,000 to 100,000. When the weight-average molecular weight of the polyvinyl acetal is equal to or greater than the above-mentioned lower limit, the shape stability (stability over time during storage) of the thermosetting resin film (x1) is easily improved. When the weight-average molecular weight of the polyvinyl acetal is equal to or less than the above-mentioned upper limit, the thermosetting resin film (x1) is easily conformable to the irregular surface of the adherend, which makes it easier to suppress the generation of voids, for example, between the adherend and the thermosetting resin film (x1). Therefore, the coverage of the surface on which the projecting electrodes are formed is likely to be good.

[0125] The glass transition temperature (Tg) of the polyvinyl acetal is preferably 40 to 80°C, more preferably 50 to 70°C, from the viewpoint of film-forming properties of the thermosetting resin film (x1) and protruding properties of the bump tops. Here, in this specification, the term "exposure property of the top of the projecting electrode" refers to the ability of the projecting electrode to penetrate the thermosetting resin film (x1) for forming a protective film when the thermosetting resin film (x1) is attached to the member with the projecting electrode, and is also referred to as the penetration property of the top of the projecting electrode.

[0126] The ratio of the three or more monomers constituting the polyvinyl acetal can be selected arbitrarily.

[0127] The content of the polymer component (A) is preferably 2 to 30 mass %, more preferably 3 to 25 mass %, and even more preferably 3 to 15 mass %, based on the total amount of the active ingredients of the thermosetting resin composition (x1-1).

[0128] The polymer component (A) may also correspond to the thermosetting component (B). In this embodiment, when the thermosetting resin composition (x1-1) contains components that correspond to both the polymer component (A) and the thermosetting component (B), the thermosetting resin composition (x1-1) is considered to contain both the polymer component (A) and the thermosetting component (B).

[0129] -Thermosetting component (B)- The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) contain a thermosetting component (B). The thermosetting component (B) is a component for curing the thermosetting resin film (x1) to form a hard cured resin film. The thermosetting component (B) may be used singly or in combination of two or more. When two or more thermosetting components (B) are used, the combination and ratio thereof can be selected arbitrarily.

[0130] Examples of the thermosetting component (B) include epoxy-based thermosetting resins, thermosetting polyimides, polyurethanes, unsaturated polyesters, and silicone resins. Among these, epoxy-based thermosetting resins are preferred. When the thermosetting component (B) is an epoxy-based thermosetting resin, the protective properties of the cured resin film and the protruding properties of the tops of the projecting electrodes can be improved, and warping of the cured resin film can be suppressed.

[0131] The epoxy thermosetting resin is composed of an epoxy resin (B1) and a thermosetting agent (B2). The epoxy thermosetting resin may be used alone or in combination of two or more. When two or more epoxy thermosetting resins are used, the combination and ratio thereof can be selected arbitrarily.

[0132] -Epoxy resin (B1)- The epoxy resin (B1) is not particularly limited, but from the viewpoint of making it easier to exhibit the effects of the present invention, it is preferable to use a combination of an epoxy resin that is solid at room temperature (hereinafter also referred to as a solid epoxy resin) and an epoxy resin that is liquid at room temperature (hereinafter also referred to as a liquid epoxy resin). In this specification, "room temperature" refers to 5 to 35°C, preferably 15 to 25°C.

[0133] The liquid epoxy resin is not particularly limited as long as it is liquid at room temperature, and examples thereof include bisphenol A type epoxy resins, bisphenol F type epoxy resins, novolac type epoxy resins, glycidyl ester type epoxy resins, biphenyl type epoxy resins, phenylene skeleton type epoxy resins, etc. Among these, bisphenol A type epoxy resins are preferred. The liquid epoxy resin may be used alone or in combination of two or more. When two or more liquid epoxy resins are used, the combination and ratio thereof can be selected arbitrarily.

[0134] The epoxy equivalent of the liquid epoxy resin is preferably 200 to 600 g / eq, more preferably 250 to 550 g / eq, and even more preferably 300 to 500 g / eq. The epoxy equivalent in this embodiment can be measured in accordance with JIS K 7236:2009.

[0135] The solid epoxy resin is not particularly limited as long as it is solid at room temperature, and examples thereof include biphenyl-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, orthocresol novolac epoxy resins, dicyclopentadiene-type epoxy resins, naphthalene-type epoxy resins, anthracene-type epoxy resins, fluorene-type epoxy resins, etc. Among these, naphthalene-type epoxy resins, dicyclopentadiene-type epoxy resins, and fluorene-type epoxy resins are preferred, and naphthalene-type epoxy resins and dicyclopentadiene-type epoxy resins are more preferred. The solid epoxy resin may be used alone or in combination of two or more. When two or more solid epoxy resins are used, the combination and ratio thereof can be selected arbitrarily.

[0136] The epoxy equivalent of the solid epoxy resin is preferably 150 to 450 g / eq, more preferably 150 to 400 g / eq.

[0137] The ratio of the content of the liquid epoxy resin (xe) to the content of the solid epoxy resin (ye) [(xe) / (ye)] is preferably 0.01 to 10.0 by mass, more preferably 0.02 to 8.0, and even more preferably 0.03 to 6.0. When the ratio [(xe) / (ye)] is within the above range, the generation of cutting waste and the like can be suppressed when cutting the cured resin film with a dicing blade, and processability can be easily improved.

[0138] The number average molecular weight (Mn) of the epoxy resin (B1) is not particularly limited, but from the viewpoints of the curability of the thermosetting resin film and the strength and heat resistance of the cured resin film after curing, it is preferably 300 to 30,000, more preferably 400 to 10,000, and even more preferably 500 to 3,000.

[0139] -Thermal hardener (B2)- The heat curing agent (B2) functions as a curing agent for the epoxy resin (B1). The thermosetting agent (B2) may be, for example, a compound having two or more functional groups per molecule that can react with an epoxy group. Examples of the functional group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an anhydride group of an acid group. A phenolic hydroxyl group, an amino group, or an anhydride group of an acid group is preferred, and a phenolic hydroxyl group or an amino group is more preferred.

[0140] Among the heat curing agents (B2), examples of phenolic curing agents having a phenolic hydroxyl group include polyfunctional phenolic resins, biphenols, novolac-type phenolic resins, dicyclopentadiene-based phenolic resins, and aralkyl phenolic resins. Among the heat curing agents (B2), examples of amine-based curing agents having an amino group include dicyandiamide (hereinafter sometimes abbreviated as "DICY"). Among these, phenolic curing agents having a phenolic hydroxyl group are preferred, and novolac-type phenolic resins are more preferred.

[0141] Of the thermosetting agents (B2), for example, the number average molecular weight (Mn) of resin components such as polyfunctional phenol resins, novolac-type phenol resins, dicyclopentadiene-based phenol resins, and aralkyl phenol resins is preferably 300 to 30,000, more preferably 400 to 10,000, and even more preferably 500 to 3,000. Of the thermosetting agent (B2), the molecular weight of the non-resin component such as biphenol or dicyandiamide is not particularly limited, but is preferably 60 to 500, for example.

[0142] The heat curing agent (B2) may be used singly or in combination of two or more. When two or more types of heat curing agents (B2) are used, the combination and ratio thereof can be selected arbitrarily.

[0143] In the thermosetting resin composition (x1-1), the content of the thermosetting agent (B2) is preferably 0.010 to 200 parts by mass, more preferably 0.020 to 150 parts by mass, even more preferably 0.050 to 100 parts by mass, and even more preferably 0.10 to 77 parts by mass, per 100 parts by mass of the epoxy resin (B1). When the content of the thermosetting agent (B2) is equal to or greater than the above-mentioned lower limit, curing of the thermosetting resin film (x1) proceeds more easily. Furthermore, when the content of the thermosetting agent (B2) is equal to or less than the above-mentioned upper limit, the moisture absorption rate of the thermosetting resin film is reduced, and the reliability of the package obtained using the thermosetting resin film (x1) is further improved.

[0144] In the thermosetting resin composition (x1-1), the content of the thermosetting component (B) (total content of the epoxy resin (B1) and the thermosetting agent (B2)) is preferably 200 to 10,000 parts by mass, more preferably 300 to 5,000 parts by mass, even more preferably 400 to 2,000 parts by mass, and even more preferably 500 to 1,000 parts by mass, per 100 parts by mass of the polymer component (A), from the viewpoint of improving the protective properties of the cured resin film.

[0145] -Curing accelerator (C)- The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a curing accelerator (C). The curing accelerator (C) is a component for adjusting the curing rate of the thermosetting resin composition (x1-1). Preferred examples of the curing accelerator (C) include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles (imidazoles in which one or more hydrogen atoms are substituted with groups other than hydrogen atoms) such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole; organic phosphines (phosphines in which one or more hydrogen atoms are substituted with organic groups) 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, from the viewpoint of making it easier to exhibit the effects of the present invention.

[0146] The curing accelerator (C) may be used singly or in combination of two or more. When two or more curing accelerators (C) are used, the combination and ratio thereof can be selected arbitrarily.

[0147] When a curing accelerator (C) is used in the thermosetting resin composition (x1-1), the content of the curing accelerator (C) is preferably 0.001 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, per 100 parts by mass of the thermosetting component (B). When the content of the curing accelerator (C) is equal to or greater than the above-mentioned lower limit, the effect of using the curing accelerator (C) is more pronounced. Furthermore, when the content of the curing accelerator (C) is equal to or less than the above-mentioned upper limit, for example, the effect of suppressing the highly polar curing accelerator (C) from migrating and segregating to the adhesive interface with the adherend in the thermosetting resin film (x1) under high temperature and high humidity conditions is enhanced, thereby further improving the reliability of the package obtained using the thermosetting resin film (x1).

[0148] -Filling material (D)- The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a filler (D). The inclusion of the filler (D) makes it easier to adjust the thermal expansion coefficient of the cured resin film obtained by curing the thermosetting resin film (x1) to an appropriate range, thereby further improving the reliability of the package obtained using the thermosetting resin film (x1). Furthermore, the inclusion of the filler (D) in the thermosetting resin film (x1) can also reduce the moisture absorption rate of the cured resin film and improve heat dissipation.

[0149] The filler (D) may be either an organic filler or an inorganic filler, but is preferably an inorganic filler. Preferred inorganic fillers include, for example, powders of silica, talc, calcium carbonate, boron nitride, etc.; beads obtained by spheronizing these inorganic fillers; surface-modified products of these inorganic fillers; single-crystal fibers of these inorganic fillers; glass fibers, etc. Among these, the inorganic filler is preferably silica.

[0150] The filler (D) may be used alone or in combination of two or more kinds. When two or more types of filler (D) are used, the combination and ratio thereof can be selected arbitrarily.

[0151] When filler (D) is used, the content of filler (D) is preferably 5 to 50 mass%, more preferably 7 to 40 mass%, and even more preferably 10 to 30 mass%, based on the total amount of active ingredients of the thermosetting resin composition, from the viewpoint of suppressing peeling of the cured resin film from the chip due to thermal expansion and thermal contraction.

[0152] The average particle size of the filler (D) is preferably from 5 nm to 1000 nm, more preferably from 5 nm to 500 nm, and even more preferably from 10 nm to 300 nm. In this specification, the particle size of the filler (D) refers to the arithmetic mean particle size obtained by measuring the particle sizes of multiple randomly selected primary particles of the filler (D) observed under an electron microscope and calculating the average value.

[0153] -Energy ray curable resin (E)- The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain an energy ray-curable resin (E). The thermosetting resin film (x1) contains the energy ray-curable resin (E), and thus its properties can be changed by irradiation with energy rays.

[0154] The energy ray curable resin (E) is obtained by polymerizing (curing) an energy ray curable compound. Examples of the energy ray curable compound include compounds having at least one polymerizable double bond in the molecule, and acrylate compounds having a (meth)acryloyl group are preferred.

[0155] Examples of acrylate compounds include chain acrylates such as trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate. Examples of the polyalkylene glycol (meth)acrylate include aliphatic skeleton-containing (meth)acrylates; alicyclic skeleton-containing (meth)acrylates such as dicyclopentanyl di(meth)acrylate; polyalkylene glycol (meth)acrylates such as polyethylene glycol di(meth)acrylate; oligoester (meth)acrylates; urethane (meth)acrylate oligomers; epoxy-modified (meth)acrylates; polyether (meth)acrylates other than the above polyalkylene glycol (meth)acrylates; and itaconic acid oligomers.

[0156] The weight average molecular weight of the energy ray-curable compound is preferably from 100 to 30,000, and more preferably from 300 to 10,000.

[0157] The energy ray-curable compound used for polymerization may be used alone or in combination of two or more. When two or more energy ray-curable compounds are used for polymerization, the combination and ratio thereof can be selected arbitrarily.

[0158] When the energy ray curable resin (E) is used, the content of the energy ray curable resin (E) is preferably 1 to 95 mass%, more preferably 5 to 90 mass%, and even more preferably 10 to 85 mass%, based on the total amount of the active ingredients of the thermosetting resin composition (x1-1).

[0159] -Photopolymerization initiator (F)- When the thermosetting resin film (x1) and the thermosetting resin composition (x1-1) contain an energy ray-curable resin (E), the thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a photopolymerization initiator (F) in order to efficiently proceed with the polymerization reaction of the energy ray-curable resin (E).

[0160] Examples of the photopolymerization initiator (F) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, 1,2-diphenylmethane, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and 2-chloroanthraquinone.

[0161] The photopolymerization initiator (F) may be used singly or in combination of two or more. When two or more photopolymerization initiators (F) are used, the combination and ratio thereof can be selected arbitrarily.

[0162] In the thermosetting resin composition (x1-1), the content of the photopolymerization initiator (F) is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass, and even more preferably 2 to 5 parts by mass, relative to 100 parts by mass of the content of the energy ray-curable resin (E).

[0163] -Additive (G)- The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain an additive (G) within the range that does not impair the effects of the present invention. The additive (G) may be a known additive and may be selected arbitrarily depending on the purpose, and is not particularly limited. Preferred examples of the additive (G) include coupling agents, crosslinking agents, surfactants, plasticizers, antistatic agents, antioxidants, leveling agents, and gettering agents.

[0164] The additive (G) may be used singly or in combination of two or more. When two or more additives (G) are used, the combination and ratio thereof can be selected arbitrarily. The content of the additive (G) is not particularly limited and may be appropriately selected depending on the purpose.

[0165] -solvent- The thermosetting resin composition (x1-1) preferably further contains a solvent. The thermosetting resin composition (x1-1) containing a solvent has good handleability. The solvent is not particularly limited, but preferred examples include hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, 2-propanol, isobutyl alcohol (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. The solvent may be used alone or in combination of two or more. When two or more solvents are used, the combination and ratio thereof can be selected arbitrarily. The solvent is preferably methyl ethyl ketone or the like, since it allows the components contained in the thermosetting resin composition (x1-1) to be mixed more uniformly.

[0166] -Method for preparing curable resin composition (x1-1)- The thermosetting resin composition (x1-1) is prepared by blending the components that constitute it. The order of addition of the components when blending is not particularly limited, and two or more components may be added simultaneously. When a solvent is used, the solvent may be mixed with any of the other components to pre-dilute the components, or the solvent may be mixed with any of the other components without pre-diluting them. The method for mixing the components during blending is not particularly limited, and may be appropriately selected from known methods such as a method of mixing by rotating a stirrer or stirring blades, a method of mixing using a mixer, or a method of mixing by adding ultrasound. The temperature and time for adding and mixing each component are not particularly limited as long as the components do not deteriorate, and may be adjusted appropriately. A temperature of 15 to 30°C is preferred.

[0167] (Energy ray curable resin film (x2)) The energy ray-curable resin film (x2) contains an energy ray-curable component (a). The energy ray-curable resin film (x2) is formed, for example, from an energy ray-curable resin composition (x2-1) containing an energy ray-curable component (a). The energy ray-curable component (a) is preferably uncured and has adhesive properties, and more preferably uncured and has adhesive properties. In the following description of this specification, "the content of each component based on the total amount of active ingredients of the energy ray-curable resin composition (x2-1)" is synonymous with "the content of each component of the energy ray-curable resin film (x2) formed from the energy ray-curable resin composition (x2-1)."

[0168] - Energy ray curable component (a) - The energy ray-curable component (a) is a component that is cured by irradiation with energy rays, and is also a component that imparts film-forming properties, flexibility, and the like to the energy ray-curable resin film (x2). Examples of the energy ray-curable component (a) include a polymer (a1) having an energy ray-curable group and a weight-average molecular weight of 80,000 to 2,000,000, and a compound (a2) having an energy ray-curable group and a molecular weight of 100 to 80,000. The polymer (a1) may be at least partially crosslinked with a crosslinking agent, or may not be crosslinked.

[0169] -Polymer (a1)- Examples of the polymer (a1) having an energy ray-curable group and a weight average molecular weight of 80,000 to 2,000,000 include an acrylic resin (a1-1) obtained by polymerizing an acrylic polymer (a11) having a functional group capable of reacting with a group possessed by another compound, and an energy ray-curable compound (a12) having a group reactive with the functional group and an energy ray-curable group such as an energy ray-curable double bond.

[0170] Examples of functional groups that can react with groups possessed by other compounds include hydroxyl groups, carboxyl groups, amino groups, substituted amino groups (groups in which one or two hydrogen atoms of an amino group are substituted with groups other than hydrogen atoms), and epoxy groups. However, from the viewpoint of preventing corrosion of circuits such as semiconductor wafers and semiconductor chips, it is preferable that the functional group be a group other than a carboxyl group. Among these, it is preferable that the functional group be a hydroxyl group.

[0171] Acrylic polymer having functional groups (a11) The acrylic polymer (a11) having a functional group may be, for example, a copolymer of an acrylic monomer having a functional group and an acrylic monomer not having a functional group, or may be a copolymer of these monomers with a monomer other than the acrylic monomer (non-acrylic monomer). The acrylic polymer (a11) may be a random copolymer or a block copolymer.

[0172] Examples of the acrylic monomer having a functional group include a hydroxyl group-containing monomer, a carboxy group-containing monomer, an amino group-containing monomer, a substituted amino group-containing monomer, and an epoxy group-containing monomer.

[0173] Examples of hydroxyl group-containing monomers include hydroxyalkyl (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 non-(meth)acrylic unsaturated alcohols (unsaturated alcohols not having a (meth)acryloyl skeleton) such as vinyl alcohol and allyl alcohol.

[0174] Examples of carboxy group-containing monomers include ethylenically unsaturated monocarboxylic acids (monocarboxylic acids having an ethylenically unsaturated bond) such as (meth)acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids (dicarboxylic acids having an ethylenically unsaturated bond) such as fumaric acid, itaconic acid, maleic acid and citraconic acid; anhydrides of the above ethylenically unsaturated dicarboxylic acids; and (meth)acrylic acid carboxyalkyl esters such as 2-carboxyethyl methacrylate.

[0175] The acrylic monomer having a functional group is preferably a hydroxyl group-containing monomer or a carboxyl group-containing monomer, and more preferably a hydroxyl group-containing monomer.

[0176] The acrylic monomer having a functional group that constitutes the acrylic polymer (a11) may be used alone or in combination of two or more. When the acrylic polymer (a11) contains two or more types of acrylic monomers having a functional group, the combination and ratio thereof can be selected arbitrarily.

[0177] Examples of acrylic monomers having no functional group include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, and isopropyl (meth)acrylate. Examples of (meth)acrylic acid alkyl esters include those in which the alkyl group constituting the alkyl ester has a chain structure and has 1 to 18 carbon atoms, such as nonyl, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate (myristyl (meth)acrylate), pentadecyl (meth)acrylate, hexadecyl (meth)acrylate (palmityl (meth)acrylate), heptadecyl (meth)acrylate, and octadecyl (meth)acrylate (stearyl (meth)acrylate).

[0178] Examples of acrylic monomers having no functional group include (meth)acrylic acid esters having an alkoxyalkyl group, such as methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and ethoxyethyl (meth)acrylate; (meth)acrylic acid esters having an aromatic group, including (meth)acrylic acid aryl esters, such as phenyl (meth)acrylate; non-crosslinkable (meth)acrylamide and derivatives thereof; and (meth)acrylic acid esters having a non-crosslinkable tertiary amino group, such as N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate.

[0179] The acrylic monomer having no functional group that constitutes the acrylic polymer (a11) may be used alone or in combination of two or more. When the acrylic polymer (a11) contains two or more types of acrylic monomers having no functional group, the combination and ratio thereof can be selected arbitrarily.

[0180] Examples of non-acrylic monomers include olefins such as ethylene and norbornene; vinyl acetate; and styrene.

[0181] The non-acrylic monomer constituting the acrylic polymer (a11) may be used singly or in combination of two or more. When the acrylic polymer (a11) is composed of two or more non-acrylic monomers, the combination and ratio thereof can be selected arbitrarily.

[0182] In the acrylic polymer (a11), the proportion (content) of the amount of structural units derived from an acrylic monomer having a functional group relative to the total mass of the structural units constituting the acrylic polymer (a11) is preferably 0.1 to 50 mass%, more preferably 1 to 40 mass%, and even more preferably 3 to 30 mass%. When the proportion is within this range, the content of the energy ray-curable group in the acrylic resin (a1-1) obtained by copolymerization of the acrylic polymer (a11) and the energy ray-curable compound (a12) makes it possible to easily adjust the degree of curing of the protective film (X) within a preferred range.

[0183] The acrylic polymer (a11) constituting the acrylic resin (a1-1) may be used singly or in combination of two or more. When the acrylic polymer (a11) constituting the acrylic resin (a1-1) is two or more types, the combination and ratio thereof can be selected arbitrarily.

[0184] The content of the acrylic resin (a1-1) is preferably 1 to 60 mass %, more preferably 3 to 50 mass %, and even more preferably 5 to 40 mass %, based on the total amount of active ingredients of the energy ray-curable resin composition (x2-1).

[0185] Energy ray curable compounds (a12) The energy ray-curable compound (a12) preferably has one or more groups selected from the group consisting of an isocyanate group, an epoxy group, and a carboxy group as a group reactive with the functional group of the acrylic polymer (a11), and more preferably has an isocyanate group as the group. When the energy ray-curable compound (a12) has, for example, an isocyanate group as the group, this isocyanate group readily reacts with the hydroxyl group of the acrylic polymer (a11) having a hydroxyl group as the functional group.

[0186] The energy ray-curable compound (a12) preferably has 1 to 5 energy ray-curable groups, and more preferably 1 or 2 energy ray-curable groups, in one molecule.

[0187] Examples of the energy ray-curable compound (a12) include 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate; an acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate; and an acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with a polyol compound and hydroxyethyl (meth)acrylate. Among these, the energy ray-curable compound (a12) is preferably 2-methacryloyloxyethyl isocyanate.

[0188] The energy ray-curable compound (a12) constituting the acrylic resin (a1-1) may be used alone or in combination of two or more. When the energy ray-curable compound (a12) constituting the acrylic resin (a1-1) is two or more types, the combination and ratio thereof can be selected arbitrarily.

[0189] In the acrylic resin (a1-1), the ratio of the content of the energy ray-curable groups derived from the energy ray-curable compound (a12) to the content of the functional groups derived from the acrylic polymer (a11) is preferably 20 to 120 mol%, more preferably 35 to 100 mol%, and even more preferably 50 to 100 mol%. When the content is within this range, the adhesive strength of the protective film (X) after curing is increased. When the energy ray-curable compound (a12) is a monofunctional compound (having one such group per molecule), the upper limit of the content is 100 mol%. However, when the energy ray-curable compound (a12) is a polyfunctional compound (having two or more such groups per molecule), the upper limit of the content may exceed 100 mol%.

[0190] The weight average molecular weight (Mw) of the polymer (a1) is preferably from 100,000 to 2,000,000, and more preferably from 300,000 to 1,500,000.

[0191] When the polymer (a1) is at least partially crosslinked with a crosslinking agent, the polymer (a1) may be one which is obtained by polymerizing a monomer which does not correspond to any of the above-mentioned monomers described as constituting the acrylic polymer (a11) and has a group which reacts with the crosslinking agent, and which is crosslinked at the group which reacts with the crosslinking agent, or may be one which is derived from the energy ray-curable compound (a12) and which is crosslinked at a group which reacts with the functional group.

[0192] The polymer (a1) may be used singly or in combination of two or more. When two or more types of polymer (a1) are used, the combination and ratio thereof can be selected arbitrarily.

[0193] -Compound (a2)- The energy ray-curable group contained in the compound (a2) having an energy ray-curable group and a weight average molecular weight (Mw) of 100 to 80,000 includes, for example, a group containing an energy ray-curable double bond, and preferred examples thereof include a (meth)acryloyl group or a vinyl group.

[0194] The compound (a2) is not particularly limited as long as it satisfies the above conditions, and examples thereof include a low-molecular-weight compound having an energy ray-curable group, an epoxy resin having an energy ray-curable group, and a phenolic resin having an energy ray-curable group.

[0195] Among the compounds (a2), examples of low molecular weight compounds having an energy ray-curable group include polyfunctional monomers or oligomers, and acrylate compounds having a (meth)acryloyl group are preferred. Examples of the acrylate compounds include 2-hydroxy-3-(meth)acryloyloxypropyl methacrylate, polyethylene glycol di(meth)acrylate, propoxylated ethoxylated bisphenol A di(meth)acrylate, 2,2-bis[4-((meth)acryloxypolyethoxy)phenyl]propane, ethoxylated bisphenol A di(meth)acrylate, 2,2-bis[4-((meth)acryloxydiethoxy)phenyl]propane, 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene, 2,2-bis[4-((meth)acryloxypolypropoxy)phenyl]propane, tricyclodecane dimethanol di(meth)acrylate, 1,10-decanediol ... bifunctional (meth)acrylates such as 6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 2,2-bis[4-((meth)acryloxyethoxy)phenyl]propane, neopentyl glycol di(meth)acrylate, ethoxylated polypropylene glycol di(meth)acrylate, and 2-hydroxy-1,3-di(meth)acryloxypropane;Examples of the polyfunctional (meth)acrylates include tris(2-(meth)acryloxyethyl)isocyanurate, ε-caprolactone-modified tris-(2-(meth)acryloxyethyl)isocyanurate, ethoxylated glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol poly(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; and polyfunctional (meth)acrylate oligomers such as urethane (meth)acrylate oligomers.

[0196] Of the compounds (a2), examples of epoxy resins having an energy ray-curable group and phenolic resins having an energy ray-curable group that can be used include those described in paragraph 0043 of JP 2013-194102 A.

[0197] The compound (a2) preferably has a weight average molecular weight (Mw) of 100 to 30,000, more preferably 300 to 10,000.

[0198] The compound (a2) may be used singly or in combination of two or more. When two or more compounds (a2) are used, the combination and ratio thereof can be selected arbitrarily.

[0199] -Polymer (b) having no energy ray-curable group- When the energy ray-curable resin composition (x2-1) and the energy ray-curable resin film (x2) contain the compound (a2) as the energy ray-curable component (a), they preferably further contain a polymer (b) that does not have an energy ray-curable group. The polymer (b) having no energy ray-curable group may be at least partially crosslinked with a crosslinking agent, or may not be crosslinked.

[0200] Examples of the polymer (b) having no energy ray-curable group include acrylic polymers, phenoxy resins, urethane resins, polyesters, rubber-based resins, acrylic urethane resins, and polyvinyl acetals. Among these, the polymer (b) is preferably an acrylic polymer (hereinafter sometimes abbreviated as "acrylic polymer (b-1)") or polyvinyl acetal.

[0201] The acrylic polymer (b-1) may be a known polymer, for example, a homopolymer of one acrylic monomer, or a copolymer of two or more acrylic monomers. Alternatively, the acrylic polymer (b-1) may be a copolymer of one or more acrylic monomers and one or more monomers other than the acrylic monomers (non-acrylic monomers).

[0202] Examples of the acrylic monomer constituting the acrylic polymer (b-1) include (meth)acrylic acid alkyl esters, (meth)acrylic acid esters having a cyclic skeleton, glycidyl group-containing (meth)acrylic acid esters, hydroxyl group-containing (meth)acrylic acid esters, and substituted amino group-containing (meth)acrylic acid esters.

[0203] Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, and isononyl (meth)acrylate. Examples of the alkyl (meth)acrylate include alkyl (meth)acrylates in which the alkyl group constituting the alkyl ester has a chain structure and has 1 to 18 carbon atoms, such as ethyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate (myristyl (meth)acrylate), pentadecyl (meth)acrylate, hexadecyl (meth)acrylate (palmityl (meth)acrylate), heptadecyl (meth)acrylate, and octadecyl (meth)acrylate (stearyl (meth)acrylate).

[0204] Examples of (meth)acrylic acid esters having a cyclic skeleton include (meth)acrylic acid cycloalkyl esters such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate; (meth)acrylic acid aralkyl esters such as benzyl (meth)acrylate; (meth)acrylic acid cycloalkenyl esters such as dicyclopentenyl (meth)acrylate; and (meth)acrylic acid cycloalkenyloxyalkyl esters such as dicyclopentenyloxyethyl (meth)acrylate.

[0205] Examples of the glycidyl group-containing (meth)acrylic acid ester include glycidyl (meth)acrylate, etc. Examples of the hydroxyl group-containing (meth)acrylic acid ester include 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. Examples of the substituted amino group-containing (meth)acrylic acid ester include N-methylaminoethyl (meth)acrylate.

[0206] Examples of non-acrylic monomers that constitute the acrylic polymer (b-1) include olefins such as ethylene and norbornene; vinyl acetate; and styrene.

[0207] As described in the section on polymer component (A), preferred examples of polyvinyl acetal include polyvinyl formal and polyvinyl butyral, with polyvinyl butyral being more preferred. Furthermore, preferred polyvinyl butyrals have structural units represented by the above formulae (i)-1, (i)-2, and (i)-3. Suitable embodiments of polyvinyl butyral are as described for polymer component (A), and therefore further description is omitted.

[0208] The polymer (b) having no energy ray-curable group and at least a portion of which is crosslinked with a crosslinking agent may be, for example, a polymer in which a reactive functional group in the polymer (b) has reacted with a crosslinking agent. The reactive functional group is not particularly limited and may be appropriately selected depending on the type of crosslinking agent, etc. For example, when the crosslinking agent is a polyisocyanate compound, examples of the reactive functional group include a hydroxyl group, a carboxyl group, and an amino group, and among these, a hydroxyl group is preferred because of its high reactivity with an isocyanate group. When the crosslinking agent is an epoxy compound, examples of the reactive functional group include a carboxy group, an amino group, and an amide group, and among these, a carboxy group is preferred because it has high reactivity with an epoxy group. However, from the viewpoint of preventing corrosion of the circuits of semiconductor wafers and semiconductor chips, it is preferable that the reactive functional group is a group other than a carboxy group.

[0209] Examples of the polymer (b) having a reactive functional group but not having an energy ray-curable group include those obtained by polymerizing at least a monomer having a reactive functional group. In the case of the acrylic polymer (b-1), one or both of the acrylic monomers and non-acrylic monomers listed as the monomers constituting it may be one having a reactive functional group. Examples of the polymer (b) having a hydroxyl group as a reactive functional group include those obtained by polymerizing a hydroxyl group-containing (meth)acrylic acid ester, and also those obtained by polymerizing a monomer in which one or more hydrogen atoms in the acrylic monomer or non-acrylic monomer listed above are substituted with the reactive functional group.

[0210] In the polymer (b) having a reactive functional group, the proportion (content) of the amount of the structural units derived from the monomer having a reactive functional group relative to the total mass of the structural units constituting the polymer (b) is preferably 1 to 20 mass%, more preferably 2 to 10 mass%. When the proportion is in this range, the degree of crosslinking in the polymer (b) becomes a more preferable range.

[0211] The weight average molecular weight (Mw) of the polymer (b) having no energy ray-curable group is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,500,000, in order to improve the film-forming properties of the energy ray-curable resin composition (x2-1).

[0212] The polymer (b) having no energy ray-curable group may be used alone or in combination of two or more. When the polymer (b) having no energy ray-curable group is used in two or more types, the combination and ratio thereof can be selected arbitrarily.

[0213] The energy ray-curable resin composition (x2-1) may contain one or both of a polymer (a1) and a compound (a2). When the energy ray-curable resin composition (x2-1) contains the compound (a2), it preferably further contains a polymer (b) having no energy ray-curable group, and in this case, it is also preferable that it further contains a polymer (a1). Alternatively, the energy ray-curable resin composition (x2-1) may not contain the compound (a2) but may contain both the polymer (a1) and the polymer (b) having no energy ray-curable group.

[0214] When the energy ray-curable resin composition (x2-1) contains the polymer (a1), the compound (a2), and the polymer (b) having no energy ray-curable group, the content of the compound (a2) is preferably 10 to 400 parts by mass, and more preferably 30 to 350 parts by mass, per 100 parts by mass of the total content of the polymer (a1) and the polymer (b) having no energy ray-curable group.

[0215] The total content of the energy ray-curable component (a) and the polymer (b) having no energy ray-curable group is preferably 5 to 90 mass%, more preferably 10 to 80 mass%, and even more preferably 20 to 70 mass%, based on the total amount of active ingredients of the energy ray-curable resin composition (x2-1). When the content of the energy ray-curable component is within this range, the energy ray curability of the energy ray-curable resin film (x2) becomes better.

[0216] The energy ray-curable resin composition (x2-1) may contain, in addition to the energy ray-curable component, one or more selected from the group consisting of a thermosetting component, a photopolymerization initiator, a filler, a coupling agent, a crosslinking agent, and an additive, depending on the purpose. For example, by using an energy ray-curable resin composition (x2-1) containing an energy ray-curable component and a thermosetting component, the adhesive strength of the formed energy ray-curable resin film (x2) to an adherend is improved by heating, and the strength of the protective film (X) formed from this energy ray-curable resin film (x2) is also improved.

[0217] The thermosetting component, photopolymerization initiator, filler, coupling agent, crosslinking agent, and additive in the energy ray-curable resin composition (x2-1) may be the same as the thermosetting component (B), photopolymerization initiator (F), filler (D), and additive (G) in the energy ray-curable resin composition (x2-1), respectively.

[0218] In the energy ray-curable resin composition (x2-1), the thermosetting component, the photopolymerization initiator, the filler, and the additive may each be used alone or in combination of two or more. When two or more are used in combination, the combination and ratio thereof can be selected arbitrarily. The contents of the thermosetting component, photopolymerization initiator, filler, and additive in the energy ray-curable resin composition (x2-1) may be adjusted appropriately depending on the purpose, and are not particularly limited.

[0219] The energy ray-curable resin composition (x2-1) preferably further contains a solvent, since dilution improves its handling properties. Examples of the solvent contained in the energy ray-curable resin composition (x2-1) include the same solvents as those in the thermosetting resin composition (x1-1). The solvent contained in the energy ray-curable resin composition (x2-1) may be used alone or in combination of two or more. When two or more types are used in combination, the combination and ratio thereof can be selected arbitrarily.

[0220] -Other ingredients- The energy ray-curable resin composition (x2-1) may contain, in addition to the above-described energy ray-curable component, appropriate amounts of components other than the curable component, namely, a curing accelerator (C), a filler (D), an additive (G), etc., as in the case of the thermosetting resin film (x1) described above.

[0221] -Method for preparing energy ray-curable resin composition (x2-1)- The energy ray-curable resin composition (x2-1) can be obtained by blending the components that constitute it. The order in which the components are added when blending them is not particularly limited, and two or more components may be added simultaneously. When a solvent is used, the solvent may be mixed with any of the other ingredients to dilute the ingredients before use, or the solvent may be mixed with any of the other ingredients without pre-diluting them. The method for mixing the ingredients during blending is not particularly limited, and may be appropriately selected from known methods such as a method of mixing by rotating a stirrer or stirring blades, a method of mixing using a mixer, or a method of mixing by applying ultrasound. The temperature and time for adding and mixing each component are not particularly limited as long as the components do not deteriorate, and may be adjusted appropriately. A temperature of 15 to 30°C is preferred.

[0222] (Preparation of protective film forming layer) The protective film forming layer of this embodiment can be produced, for example, by applying the protective film forming composition of this embodiment to the surface on which it is to be formed, and drying it as necessary. The protective film-forming composition may be applied by a known method, such as a method using various coaters such as an air knife coater, blade coater, bar coater, gravure coater, roll coater, roll knife coater, curtain coater, die coater, knife coater, screen coater, Mayer bar coater, or kiss coater. The drying conditions after applying the protective film-forming composition are not particularly limited, but may be, for example, a drying temperature of 70 to 130° C. and a drying time of 10 seconds to 5 minutes.

[0223] <Buffer layer> The composite sheet for forming a protective film of this embodiment may further have a buffer layer between the substrate and the pressure-sensitive adhesive layer. The buffer layer is a layer that has a buffering effect against forces applied to the buffer layer and a layer directly or indirectly adjacent thereto. Here, the "layer directly or indirectly adjacent to the buffer layer" mainly refers to the protective film-forming layer of this embodiment.

[0224] The buffer layer may be a single layer or a plurality of layers, two or more of which may be the same or different, and the combination of these layers is not particularly limited.

[0225] The thickness of the buffer layer can be adjusted appropriately depending on the height of the projecting electrode to be protected, but from the viewpoint of making it easier to achieve the effects of the present invention even for relatively tall projecting electrodes, the thickness is preferably 50 to 700 μm, more preferably 100 to 600 μm, and even more preferably 150 to 500 μm.

[0226] (Storage modulus (G') of buffer layer at 80°C) In the composite sheet for forming a protective film of this embodiment, the storage modulus (G') of the buffer layer at 80°C is preferably 0.08 MPa or more. When the storage modulus (G') of the buffer layer at 80°C is 0.08 MPa or more, it is easier to ensure the protruding electrode penetration of the protective film forming layer (hereinafter also referred to as "protective film forming film"), and it is easier to ensure the connection reliability between the chip with protruding electrodes and the substrate. Here, from the viewpoint of more easily ensuring the projecting electrode penetration ability of the protective film-forming film, the storage modulus (G') of the buffer layer at 80°C is more preferably 0.10 MPa or more, even more preferably 0.12 MPa or more, even more preferably 0.14 MPa or more, and even more preferably 0.16 MPa or more. In addition, the storage modulus (G') of the buffer layer at 80°C is preferably 0.4 MPa or less, from the viewpoint of making it easier to adjust the loss tangent (tanδ) of the buffer layer at 80°C described later to 1.02 or more, and making it easier to ensure the embeddability of the projecting electrode in the protective film-forming film. The storage modulus (G') of the buffer layer at 80°C is a value measured by the method described in the examples below.

[0227] (loss tangent (tanδ) of buffer layer at 80°C) In the composite sheet for forming a protective film of this embodiment, the loss tangent (tan δ) of the buffer layer at 80° C. is preferably 1.02 or more. When the loss tangent (tan δ) of the buffer layer at 80° C. is 1.02 or more, the embedding ability of the protective film-forming film into the projecting electrodes (the penetration ability of the protective film-forming film into the periphery of the base of the projecting electrodes) is easily ensured. Here, from the viewpoint of more easily ensuring the embedding ability of the projecting electrode in the protective film-forming film, the loss tangent (tanδ) of the buffer layer at 80°C is more preferably 1.05 or more, even more preferably 1.08 or more, even more preferably 1.12 or more, and even more preferably 1.16 or more. In addition, the loss tangent (tanδ) of the buffer layer at 80°C is preferably 2.00 or less, from the viewpoint of making it easier to adjust the storage modulus (G') of the buffer layer at 80°C to 0.08 or more and making it easier to ensure the projecting electrode penetration ability of the protective film-forming film. The loss tangent (tan δ) of the buffer layer at 80° C. means a value measured by the method described in the examples below.

[0228] In this embodiment, the storage modulus (G') at 80° C. and the loss tangent (tan δ) at 80° C. of the buffer layer can be adjusted appropriately by adjusting the composition of the buffer layer, etc. The buffer layer will be described in detail below, taking into consideration the method for adjusting the storage modulus (G') at 80°C and the loss tangent (tan δ) at 80°C of the buffer layer.

[0229] (urethane (meth)acrylate) Urethane (meth)acrylate is a compound having at least a (meth)acryloyl group and a urethane bond, and has the property of polymerizing upon irradiation with energy rays. The use of urethane (meth)acrylate imparts flexibility to the buffer layer, making it easier to adjust the storage modulus (G') at 80°C and loss tangent (tanδ) at 80°C of the buffer layer within the above ranges. The urethane (meth)acrylate may be monofunctional or polyfunctional. In this embodiment, polyfunctional urethane (meth)acrylate is preferred, and from the viewpoint of easily adjusting the storage modulus (G') at 80°C and the loss tangent (tanδ) at 80°C of the buffer layer to the above ranges, bifunctional urethane (meth)acrylate is preferred. The urethane (meth)acrylate may be an oligomer, a polymer, or a mixture thereof. In this embodiment, a urethane (meth)acrylate oligomer is preferred. The urethane (meth)acrylate can be obtained, for example, by reacting a polyol compound with a polyvalent isocyanate compound to obtain a terminal isocyanate urethane prepolymer, and then reacting the resulting prepolymer with a (meth)acrylate having a hydroxy group. The urethane (meth)acrylate may be used alone or in combination of two or more. The content of the urethane (meth)acrylate in the buffer layer-forming composition is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more, from the viewpoint of easily adjusting the storage modulus (G') at 80°C and the loss tangent (tanδ) at 80°C of the buffer layer within the above ranges. The content of the urethane (meth)acrylate in the intermediate layer-forming composition is preferably 70% by mass or less, more preferably 65% ​​by mass or less, and even more preferably 50% by mass or less.

[0230] (Polymerizable monomer) The polymerizable monomer is preferably a polymerizable compound other than the above-mentioned urethane (meth)acrylate, which is polymerizable with other components upon irradiation with energy rays. Specifically, the polymerizable monomer is preferably a compound having at least one (meth)acryloyl group. Examples of the polymerizable monomer include (meth)acrylates having an alkyl group having 1 to 30 carbon atoms; (meth)acrylates having a functional group such as a hydroxyl group, an amide group, an amino group, or an epoxy group; (meth)acrylates having an alicyclic structure; (meth)acrylates having an aromatic structure; (meth)acrylates having a heterocyclic structure; and vinyl compounds such as styrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinylformamide, N-vinylpyrrolidone, and N-vinylcaprolactam. Examples of (meth)acrylates having an alkyl group having 1 to 30 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, and eicosyl (meth)acrylate. Examples of the (meth)acrylate having a functional group include hydroxyl group-containing (meth)acrylates such as 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; (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, and N-methylol (meth)acrylamide. Amide group-containing compounds such as N-methylolpropane(meth)acrylamide, N-methylolpropane(meth)acrylamide, N-methoxymethyl(meth)acrylamide, and N-butoxymethyl(meth)acrylamide; amino group-containing (meth)acrylates such as primary amino group-containing (meth)acrylates, secondary amino group-containing (meth)acrylates, and tertiary amino group-containing (meth)acrylates; and epoxy group-containing (meth)acrylates such as glycidyl(meth)acrylate, methylglycidyl(meth)acrylate, and allyl glycidyl ether. Examples of (meth)acrylates having an alicyclic structure include isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxy (meth)acrylate, cyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, and adamantane (meth)acrylate. Examples of the (meth)acrylate having an aromatic structure include phenylhydroxypropyl (meth)acrylate, benzyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate. Examples of the (meth)acrylate having a heterocyclic structure include tetrahydrofurfuryl (meth)acrylate and morpholine (meth)acrylate. In this embodiment, the polymerizable monomer preferably includes a (meth)acrylate having an alkyl group with 1 to 30 carbon atoms and a (meth)acrylate having an alicyclic structure. From the viewpoint of easily adjusting the storage modulus (G') at 80°C and the loss tangent (tanδ) at 80°C of the buffer layer to the above ranges, a (meth)acrylate having an alkyl group with 4 to 14 carbon atoms is preferred, and as the (meth)acrylate having an alicyclic structure, isobornyl (meth)acrylate and trimethylcyclohexyl (meth)acrylate are preferred. When a crosslinking agent is contained in the buffer layer-forming composition, a (meth)acrylate having a functional group that can react with the crosslinking agent is not preferred. This is because the crosslinked structure formed by the crosslinking reaction may increase the residual stress in the buffer layer. For example, a buffer layer-forming composition containing a polyisocyanate-based crosslinking agent and a (meth)acrylate having a hydroxyl group is not preferred. The content of the polymerizable monomer in the buffer layer-forming composition is preferably 20% by mass or more, and more preferably 30% by mass or more, from the viewpoint of easily adjusting the storage modulus (G') at 80°C and the loss tangent (tanδ) at 80°C of the buffer layer within the above ranges. The content of the polymerizable monomer in the buffer layer-forming composition is preferably 80% by mass or less, and more preferably 70% by mass or less. Furthermore, the mass ratio of the urethane (meth)acrylate to the polymerizable monomer (urethane (meth)acrylate / polymerizable monomer) in a total of 100 parts by mass of the urethane (meth)acrylate and the polymerizable monomer is preferably 20 / 80 to 80 / 20, and more preferably 30 / 70 to 70 / 30, from the viewpoint of easily adjusting the storage modulus (G') at 80°C and the loss tangent (tanδ) at 80°C of the buffer layer within the above ranges.

[0231] (Photopolymerization initiator) When the buffer layer-forming composition contains the urethane (meth)acrylate and polymerizable monomer, it preferably contains a photopolymerization initiator, which ensures that polymerization proceeds reliably and makes it easier to adjust the storage modulus (G') at 80°C and loss tangent (tanδ) at 80°C of the buffer layer to fall within the above-mentioned ranges. Examples of photopolymerization initiators include benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, and peroxide compounds, as well as photosensitizers such as amines and quinones. Specific examples include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and 2,2-dimethoxy-1,2-diphenylethan-1-one. These photopolymerization initiators may be used alone or in combination of two or more. The amount of the photopolymerization initiator is preferably 0.05 to 15 parts by mass, more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the total of the urethane (meth)acrylate and the polymerizable monomer.

[0232] (chain transfer agent) The buffer layer-forming composition preferably contains a chain transfer agent. The chain transfer agent can initiate a chain transfer reaction and adjust the progress of the curing reaction of the buffer layer-forming composition. The inclusion of a chain transfer agent allows components with short molecular chains to remain relatively even after curing, resulting in a polymer with a relatively flexible structure after curing. As a result, the storage modulus (G') at 80°C and loss tangent (tanδ) at 80°C of the buffer layer can be easily adjusted to fall within the above-mentioned ranges. Examples of the chain transfer agent include thiol group-containing compounds. Examples of the thiol group-containing compounds include nonyl mercaptan, 1-dodecanethiol, 1,2-ethanedithiol, 1,3-propanedithiol, triazine thiol, triazine dithiol, triazine trithiol, 1,2,3-propane trithiol, tetraethylene glycol-bis(3-mercaptopropionate), trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetraki ... Examples of the chain transfer agent include erythritol tetrakisthioglucarate, dipentaerythritol hexakis(3-mercaptopropionate), tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, 1,4-bis(3-mercaptobutyryloxy)butane, pentaerythritol tetrakis(3-mercaptobutyrate), and 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione. One or more types of chain transfer agents may be used in combination. The amount (content) of the chain transfer agent is preferably 1.0 parts by mass or more and 2.5 parts by mass or less, more preferably 1.2 parts by mass or more and 2.0 parts by mass or less, and even more preferably 1.3 parts by mass or more and 1.8 parts by mass or less, relative to 100 parts by mass of the total of the urethane (meth)acrylate and the polymerizable monomer, from the viewpoint of easily adjusting the storage modulus (G') at 80°C and the loss tangent (tanδ) at 80°C of the buffer layer within the above ranges.

[0233] (Other ingredients) The buffer layer may contain other components (for example, an antistatic agent, a fluxing agent, etc.) The other components are not particularly limited and are appropriately selected depending on the purpose.

[0234] (Creating a buffer layer) As a composition for forming a buffer layer (buffer layer-forming composition), for example, a buffer layer-forming composition containing the above-mentioned components, or a composition obtained by diluting the buffer layer-forming composition with a solvent or the like is prepared. Examples of the solvent include organic solvents such as methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, and isopropanol. The buffer layer-forming composition or the like is then applied to a release film or a substrate by a known method such as spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, or gravure coating to form a coating film, and the coating film is cured to form an intermediate layer on the substrate. In this embodiment, the coating film is preferably cured by irradiation with energy rays. Examples of energy rays include ultraviolet rays and electron beams, with ultraviolet rays being preferred. Furthermore, in this embodiment, it is preferable to cure the coating film by irradiating it with energy rays multiple times, which allows the degree of cure of the buffer layer to be controlled, and makes it easier to adjust the storage modulus (G') at 80°C and the loss tangent (tanδ) at 80°C of the buffer layer to fall within the above ranges. When the energy rays are ultraviolet rays, the ultraviolet irradiation conditions are preferably such that the illuminance of the ultraviolet rays is 30 to 500 mW / cm 2 , more preferably 50 to 340 mW / cm 2 and the irradiation amount (integrated light amount) of ultraviolet light is preferably 100 to 2500 mJ / cm 2 , more preferably 150 to 2000 mJ / cm 2 is. When ultraviolet irradiation is performed multiple times, the irradiation conditions are preferably such that the illuminance and dose are greater than those of the previous irradiation. Furthermore, after the coating film is exposed to oxygen and irradiated with energy rays, the coating film may be further irradiated with energy rays while being shielded from oxygen.

[0235] <Method of manufacturing the composite sheet for forming a protective film> The composite sheet for forming a protective film of this embodiment can be produced by laminating the above-mentioned layers in order so that they are in a corresponding positional relationship. A composite sheet for forming a protective film, which has a substrate, an adhesive layer, a fired metal material layer, and a protective film forming layer in this order, can be produced, for example, by the method shown below. A pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer is applied to the release-treated surface of a release film and dried to form a pressure-sensitive adhesive layer on the release film. Thereafter, the surface of the pressure-sensitive adhesive layer that is not in contact with the release film is attached to a substrate to obtain a laminate (first laminate sheet) in which the substrate, pressure-sensitive adhesive layer, and release film are laminated in this order. Separately, a composition for forming a fired metal material layer is applied to the release-treated surface of a release film, and dried as necessary, to form a fired metal material layer on the release film. Furthermore, a protective film-forming composition is applied to the release-treated surface of the release film and dried as necessary to form a protective film-forming layer on the release film. Next, after removing the release film from the first laminate sheet, the exposed surface of the pressure-sensitive adhesive layer opposite the substrate and the exposed surface of the fired metal material layer opposite the release film are bonded together. After removing the release film from the fired metal layer, the exposed surface of the fired metal layer is bonded to the exposed surface of the protective film-forming layer opposite the release film, thereby obtaining a composite sheet for forming a protective film having a structure in which the substrate, the pressure-sensitive adhesive layer, the protective film-forming layer, and the release film are laminated in this order. The release film provided on the protective film forming layer in the composite sheet for forming a protective film may be removed at any stage from the production of the composite sheet for forming a protective film to the end of use.

[0236] A composite sheet for forming a protective film having layers other than the above-mentioned layers can be produced by adding or omitting appropriate steps in the above-mentioned production method so that the stacking positions of each layer are in the desired positions.

[0237] [Method of manufacturing semiconductor device] The method for manufacturing a semiconductor device according to this embodiment will be described below with reference to the drawings.

[0238] The method for manufacturing a semiconductor device of this embodiment includes a step of attaching a protective film forming layer of the composite sheet for forming a protective film of this embodiment to the projecting electrode forming surface of a member with projecting electrodes on which projecting electrodes are formed, and a step of separating the composite sheet for forming a protective film at the interface (Y) to produce a laminate of the member with projecting electrodes and the protective film forming layer. The method for manufacturing a semiconductor device of this embodiment further includes a step of connecting the electrodes of the substrate and the protruding electrodes of the laminate by sintering. In detail, the method for manufacturing a semiconductor device according to this embodiment is preferably a manufacturing method including the following steps 1 to 4. Step 1: A step of laminating the composite sheet for forming a protective film on a semiconductor wafer by attaching the protective film forming layer of the composite sheet for forming a protective film of this embodiment to the protruding electrode forming surface of a member with protruding electrodes and causing the tops of the protruding electrodes to protrude from the protective film forming layer (hereinafter also referred to as the "attaching step"). Step 2: A step of separating the composite sheets for forming a protective film laminated in Step 1 at the interface (Y) (hereinafter also referred to as the "separation step"). Step 3: After Step 2, a step of dividing the semiconductor wafer to produce semiconductor chips (hereinafter also referred to as the "dividing step"), and a step of cutting the protective film after Step 2 (hereinafter also referred to as the "cutting step"). Step 4: A step of connecting the electrodes of the substrate and the protruding electrodes of the laminate by sintering (hereinafter also referred to as the "mounting step"). Each step will be described below with reference to the drawings. In the following description, the case where the composite sheet 1a for forming a protective film is used will be described as an example, but it is of course also possible to use the composite sheet 1b for forming a protective film.

[0239] <Process 1: Pasting process> FIG. 3 is a schematic cross-sectional view for explaining the bonding step. 3(a) and (b) show a process of attaching the composite sheet for forming a protective film 1a to the surface of the semiconductor wafer 20 on which the protruding electrodes are formed. In the bonding step, for example, first, as shown in FIG. 3(a), the composite sheet 1a for forming a protective film is placed so that the protective film forming layer 13 faces the surface of the semiconductor wafer 20 on which the protruding electrodes are formed. Next, the protective film forming layer 13 is brought into contact with the projecting electrodes 21 on the semiconductor wafer 20, and the composite sheet 1a for forming a protective film is pressed against the semiconductor wafer 20. By pressing, the protective film forming layer 13 is successively pressure-bonded to the surfaces of the projecting electrodes 21 and the projecting electrode forming surface of the semiconductor wafer 20. When the composite sheet 1a for forming a protective film is pressure-bonded to the semiconductor wafer 20, pressure is applied to the protective film forming layer 13 from the projecting electrodes 21, causing tears in the protective film forming layer 13. Ultimately, as shown in FIG. 3(b), the upper portions of the projecting electrodes 21 penetrate the protective film forming layer 13.

[0240] The height of the projecting electrodes 21 is not particularly limited, but when the projecting electrodes are ball bumps, it is preferably 120 to 300 μm, more preferably 150 to 270 μm, and even more preferably 180 to 240 μm. When the projecting electrodes are columnar electrodes (pillars), it is preferably 5 to 120 μm, more preferably 10 to 100 μm, and even more preferably 15 to 80 μm. In this specification, the "height of the projecting electrode" means the height of the projecting electrode at the highest position from the projecting electrode forming surface. The width of the projecting electrodes 21 is not particularly limited, but when the projecting electrodes are ball bumps, it is preferably 170 to 350 μm, more preferably 200 to 320 μm, and even more preferably 230 to 290 μm.When the projecting electrodes are columnar electrodes (pillars), it is preferably 5 to 80 μm, more preferably 10 to 70 μm, and even more preferably 15 to 50 μm. In this specification, the "width of the protruding electrode" means the maximum length of the line segment obtained by drawing a straight line between two different points on the surface of the protruding electrode when viewed in a planar view looking down on the protruding electrode from a direction perpendicular to the surface on which the protruding electrode is formed. The distance between adjacent projecting electrodes 21 is not particularly limited, but when the projecting electrodes are ball bumps, it is preferably 250 to 800 μm, more preferably 300 to 600 μm, and even more preferably 350 to 500 μm.When the projecting electrodes are columnar electrodes (pillars), it is preferably 5 to 300 μm, more preferably 10 to 150 μm, and even more preferably 20 to 100 μm. In this specification, the "distance between adjacent projecting electrodes" means the minimum distance between the surfaces of adjacent projecting electrodes.

[0241] The composite sheet for forming a protective film 1a can be pressure-bonded to the semiconductor wafer 20 by any known method for pressing and attaching various sheets to an object, such as a method using a roller laminator. The heating temperature when the composite sheet for forming a protective film 1a is pressure-bonded to the semiconductor wafer 20 is not particularly limited, and may be, for example, 60 to 100°C, and preferably 70 to 90°C. The pressure when the composite sheet for forming a protective film 1a is pressure-bonded to the semiconductor wafer 20 is not particularly limited, and may be, for example, 0.1 to 1.5 MPa, and preferably 0.3 to 1 MPa. The speed at which the composite sheet for forming a protective film 1a is attached to the semiconductor wafer 20 is not particularly limited, and is usually about 2 to 3 mm / s.

[0242] After the attachment step, if necessary, the surface (back surface) of the semiconductor wafer 20 opposite to the surface on which the protruding electrodes are formed may be ground, and further, another composite sheet for forming a protective film (not shown) may be attached to the back surface after grinding.

[0243] <Process 2: Separation process> FIG. 4 is a schematic cross-sectional view for explaining the separation step. After the bonding process, as shown in Figure 4, the composite sheet 1a for forming a protective film is separated at the interface (Y), and layers other than the protective film forming layer 13 are removed from the composite sheet 1a for forming a protective film, thereby obtaining a semiconductor wafer 30 with a protective film forming layer, which comprises a semiconductor wafer 20 and the protective film forming layer 13 provided on the protruding electrode forming surface of the semiconductor wafer 20. The layers other than the protective film forming layer 13 can be removed by a known method (for example, an adsorption pad, etc.). In step 2, the sintered metal material layer 12 in contact with the protective film forming layer 13 is peeled off from the protective film forming layer 13 when they are separated at the interface (Y). On the other hand, the sintered metal material layer 12 in contact with the top of the projecting electrode 21 is broken off when they are separated at the interface (Y) and remains on the top of the projecting electrode 21. This forms a joint made of sintered metal material on the top of the projecting electrode.

[0244] <Process 3: Division process, cutting process> FIG. 5 is a schematic cross-sectional view for explaining the dividing step and the cutting step. After step 2, as shown in Fig. 5, in a dividing step, the semiconductor wafer 20 is divided to produce semiconductor chips. In addition, in a cutting step, the protective film forming layer 13 is cut to form a cut protective film forming layer 13. This results in a protective film-coated semiconductor chip 40 having the cut protective film forming layer 13 on the protruding electrode forming surface of the semiconductor chip.

[0245] The dividing step and cutting step can be carried out by known methods. The order in which the dividing step and the cutting step are performed is not particularly limited, but it is preferable to perform the dividing step and the cutting step simultaneously, or to perform the dividing step and the cutting step in that order. When the dividing step and the cutting step are performed in this order, for example, the dividing step may be performed by a known dicing method, and then the cutting step may be performed immediately thereafter. Dicing can be performed by providing a dicing sheet (not shown) on the back surface of the semiconductor wafer 20 (which may be the back surface after grinding). In the cutting step, the protective film forming layer 13 is cut along the planned or completed dividing points of the semiconductor wafer 20 (in other words, along the outer periphery of the semiconductor chip 40).

[0246] <Process 4: Mounting process> In the mounting process, the electrodes 61 of the substrate 60 and the protruding electrodes 21 of the laminate are connected by sintering. The heat of sintering heats the protective film forming layer 13, making it temporarily fluid and flowing into the periphery of the connection between the electrode 61 of the substrate 60 and the projecting electrode 21, and then thermally hardening. As a result, while the electrode 61 and the projecting electrode 21 are electrically connected, the periphery of the connection is covered with the protective film 13'. That is, the electrical connection between the electrode 61 and the projecting electrode 21 and the thermal curing of the protective film forming layer 13 can be carried out simultaneously, and furthermore, a reinforcing effect is achieved by covering the periphery of the connection with the protective film 13'. However, the protective film forming layer 13 does not necessarily have to be hardened during sintering, and it is of course possible to separately harden the protective film forming layer 13 before sintering. The protective film forming layer 13 may be thermosetting or energy ray curable, but is preferably thermosetting from the viewpoint of exerting the reinforcing effect of covering the periphery of the connection portion with the protective film 13'. The pressure applied to the laminate during sintering may be 3 MPa or more, 8 MPa or more, 3 to 25 MPa, or 8 to 25 MPa. The temperature during sintering may be 260 to 400°C, 260 to 3800°C, or 280 to 360°C.

[0247] Thereafter, a semiconductor package is produced according to a known method using the circuit board thus obtained on which the semiconductor chip is already mounted, and the desired semiconductor device can be manufactured using this semiconductor package. [Example]

[0248] The present invention will be specifically described with reference to the following examples, but the present invention is not limited to these examples.

[0249] [Production of film-shaped sintered metal material] <Ingredients used> (1) Sinterable metal particle-containing paste Silver nanopaste (Alconano silver paste ANP-4 (organic coated composite silver nanopaste, Applied Nanoparticles Research Institute Co., Ltd.: alcohol derivative coated silver particles, metal content 80 wt% or more, average particle size 100 nm or less, 25 wt% or more silver particles))

[0250] (2) Binder resin Acrylic copolymer (1) (2-ethylhexyl methacrylate (2EHMA) / lauryl methacrylate (LMA) copolymer, copolymer mass ratio 60 / 40, weight average molecular weight (Mw): 260,000, glass transition temperature (Tg): -35°C) Acrylic copolymer (2) (2-ethylhexyl methacrylate (2EHMA) / lauryl methacrylate (LMA) copolymer, copolymer mass ratio 50 / 50, weight average molecular weight (Mw): 230,000, glass transition temperature (Tg): -41°C) Acrylic polymer (3) (isodecyl methacrylate polymer, weight average molecular weight (Mw): 230,000, glass transition temperature (Tg): -40°C) Tg was calculated using the Fox equation.

[0251] (Production Example A1: Production of Film-Shaped Metal Sintered Material A1) 12 parts by mass of the acrylic copolymer (1) and 88 parts by mass of silver nanopaste were mixed, and the solid concentration was adjusted to 80% by mass using butyl carbitol acetate as a dilution solvent to obtain a fired metal material composition. Next, the obtained metal sintered material composition was printed on one side (release-treated side) of a release film ("SP-PET381031" manufactured by Lintec Corporation, thickness 38 μm) to form a printed layer. The printed layer was then dried at 150 ° C for 10 minutes to obtain a film-like metal sintered material A1 with a thickness of 20 μm.

[0252] (Production Example A2: Production of Film-Shaped Metal Sintered Material A2) The printing amount per unit area of ​​the fired metal material composition during printing layer formation was increased, and a 60 μm-thick fired metal film A2 was obtained in the same manner as in Production Example A1.

[0253] (Production Example A3: Production of Film-Shaped Metal Sintered Material A3) A film-shaped sintered metal material A3 having a thickness of 20 μm was obtained in the same manner as in Production Example A1, except that the acrylic copolymer (1) was changed to the acrylic copolymer (2).

[0254] (Production Example A4: Production of film-shaped metal baking material A4) A film-shaped sintered metal material A4 having a thickness of 20 μm was obtained in the same manner as in Production Example A1, except that the acrylic copolymer (1) was changed to the acrylic polymer (3).

[0255] [Preparation of adhesive layer] 91 parts by mass of n-butyl acrylate and 9 parts by mass of acrylic acid were copolymerized by solution polymerization to obtain an acrylic copolymer (weight average molecular weight (Mw): 600,000). Next, 100 parts by mass of this acrylic copolymer and 2 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate L") as a crosslinking agent were mixed in ethyl acetate to a solids concentration of 25% by mass to prepare a pressure-sensitive adhesive composition. The adhesive composition was then applied to one side of a substrate (Toray Industries, Inc., "Lumirror" T60 polyester film, thickness 50 μm) to form a coating film, and the coating film was dried at 100°C for 60 seconds to produce a substrate (1) with an adhesive layer having a thickness of 10 μm. Also, an adhesive tape (manufactured by Lintec Corporation, product name "Adwill D-841") consisting of a substrate and an adhesive layer was prepared as the substrate (2) with an adhesive layer. Furthermore, the above-mentioned adhesive composition was applied to the release-treated surface of a PET-based release film (manufactured by Lintec Corporation, product name "SP-PET381130", thickness 38 μm) to form a coating film, and the coating film was dried at 100°C for 60 seconds to produce an adhesive layer with a single-sided release film having an adhesive layer with a thickness of 10 μm.

[0256] [Preparation of protective film forming layer] (1) Raw materials for the protective film-forming composition The raw materials used in the production of the protective film-forming composition are shown below. Polymer component (A) (A)-1: Polyvinyl butyral having structural units represented by the following formulas (i)-1, (i)-2, and (i)-3 ("S-LEC BL-10" manufactured by Sekisui Chemical Co., Ltd., weight average molecular weight (Mw): 25,000, glass transition temperature (Tg): 59°C). [ka] (In the formula, l is about 28, m is 1 to 3, and n is an integer of 68 to 74.) Epoxy resin (B1) (B1)-1: Liquid modified bisphenol A epoxy resin (DIC Corporation, "Epicron EXA-4850-150", molecular weight 900, epoxy equivalent 450 g / eq) (B1)-2: Dicyclopentadiene-type epoxy resin (DIC Corporation "Epicron HP-7200HH", epoxy equivalent 254-264g / eq) Heat hardener (B2) (B2)-1: O-cresol novolac resin (DIC Corporation "Phenolite KA-1160") Curing accelerator (C) (C)-1: 2-Phenyl-4,5-dihydroxymethylimidazole ("Curezol 2PHZ-PW" manufactured by Shikoku Chemicals Corporation) ·Filling material (D) (D)-1: Spherical silica modified with epoxy groups ("Admanano YA050C-MKK" manufactured by Admatechs Co., Ltd., average particle size 50 nm) Additives (G) (G)-1: Surfactant (acrylic polymer, BYK "BYK-361N") (G)-2: Silicone oil (aralkyl-modified silicone oil, "XF42-334" manufactured by Momentive Performance Materials Japan)

[0257] (2) Production of protective film-forming composition Polymer component (A)-1 (100 parts by weight), epoxy resin (B1)-1 (290 parts by weight), epoxy resin (B1)-2 (220 parts by weight), heat curing agent (B2)-1 (160 parts by weight), curing accelerator (C)-1 (2 parts by weight), filler (D)-1 (200 parts by weight), additive (G)-1 (25 parts by weight), and additive (G)-2 (3 parts by weight) were dissolved or dispersed in methyl ethyl ketone and stirred at 23°C to obtain a protective film-forming composition with a total concentration of all components other than the solvent of 45% by weight. Note that the amounts of all components other than the solvent shown here are the amounts of the target product excluding the solvent.

[0258] (3) Manufacturing of the protective film forming layer A PET-based release film (manufactured by Lintec Corporation, product name "SP-PET381031", thickness 38 μm) was used, and the protective film-forming composition obtained above was applied to the release-treated surface and dried at 100°C for 2 minutes to produce a thermosetting protective film-forming composition with a thickness of 30 μm.

[0259] [Creating the buffer layer] (1) Preparation of buffer layer (measurement sample) A buffer layer-forming composition A was obtained by blending 40 parts by mass of aliphatic urethane acrylate (CN966J75 NS, manufactured by Arkema Inc.), 40 parts by mass of isobornyl acrylate (IBXA), and 20 parts by mass of dodecyl acrylate, for a total of 100 parts by mass, with 3.0 parts by mass of a photopolymerization initiator (Irgacure 1173 (2-hydroxy-2-methyl-1-phenyl-propan-1-one), manufactured by BASF) and 1.5 parts by mass of a chain transfer agent (Karenz MT PE1 (pentaerythritol tetrakis(3-mercaptobutyrate)), manufactured by Showa Denko K.K.). The obtained buffer layer-forming composition A was applied to a PET-based release film (manufactured by Lintec Corporation, SP-PET382150, thickness 38 μm) using a knife method to a thickness of 200 μm to form a buffer layer composition layer. Next, the formed buffer layer composition layer was laminated with a PET-based release film (manufactured by Lintec Corporation, SP-PET381130, thickness 38 μm) to insulate the buffer layer composition layer from oxygen. Subsequently, a high-pressure mercury lamp was used to illuminate the buffer layer composition layer at an illuminance of 80 mW / cm. 2 , cumulative light intensity 200mJ / cm 2 After ultraviolet irradiation under the conditions of 330 mW / cm using a metal halide lamp, 2 , irradiation amount 1260mJ / cm 2 The buffer layer composition layer was cured by irradiating it with ultraviolet light under the conditions above, thereby obtaining a buffer layer A having a thickness of 200 μm.

[0260] Next, a sample for measuring the shear storage modulus and loss tangent of the buffer layer A was prepared. The sample had a diameter of 8 mm and a thickness of 1 mm (five 200 μm buffer layers stacked together). The shear storage modulus G' and loss tangent tanδ were measured using an Anton Paar MCR302 rheometer. The measurement conditions were as follows: The sample, from which the release films had been removed from the top and bottom, was sandwiched between parallel plates, and shear stress was applied to the sample at a measurement temperature of 0 to 100°C, a gap of 1 mm, a strain of 0.05 to 0.5%, and an angular frequency of 1 Hz. The shear storage modulus G' and loss tangent tanδ at 80°C were calculated. The shear storage modulus G' and loss tangent tanδ of the buffer layer A at 80°C were as follows. Shear storage modulus G' at 80°C: 0.16 MPa Loss tangent tanδ at 80℃: 1.17

[0261] (2) Preparation of a buffer layer (a buffer layer for a composite sheet for forming a protective film) The buffer layer-forming composition A was applied to one side of a polyethylene terephthalate film (manufactured by Toray Industries, Inc., "Polyester Film "Lumilar" U34", thickness 50 μm) as a substrate using a knife method to form a buffer layer composition layer with a thickness of 200 μm. Next, the formed buffer layer composition layer was laminated with a PET-based release film (manufactured by Lintec Corporation, SP-PET381130, thickness 38 μm) to insulate the buffer layer composition layer from oxygen. Next, a high-pressure mercury lamp was used to illuminate the buffer layer composition layer at an illuminance of 80 mW / cm. 2 , cumulative light intensity 200mJ / cm 2 After ultraviolet irradiation under the conditions of 330 mW / cm using a metal halide lamp, 2 , irradiation amount 1260mJ / cm 2 The buffer layer composition layer was cured by irradiating it with ultraviolet light under the conditions above, thereby forming a buffer layer A1 having a thickness of 200 μm. As a result, a laminate sheet (hereinafter also referred to as "second laminate sheet") was obtained in which the substrate, the buffer layer, and the release film were laminated in this order in the thickness direction.

[0262] [Examples 1 to 4, Comparative Examples 1 and 2] Example 1 (1) Preparation of composite sheet for forming protective film The release film was removed from the second laminate sheet obtained above, and the pressure-sensitive adhesive layer with a single-sided release film obtained above was attached to the exposed surface of the resulting buffer layer. The release film was removed from the pressure-sensitive adhesive layer after this attachment, and the film-shaped sintered metal material A1 with a single-sided release film obtained above was attached to the exposed surface of the resulting pressure-sensitive adhesive layer. Then, the release film was removed from the film-shaped sintered metal material A1, and the exposed surface of the film for forming a protective film with a single-sided release film obtained above was attached to the exposed surface of the resulting film-shaped sintered metal material A1, to obtain a composite sheet for forming a protective film. (2) Preparation of samples for adhesive strength measurement A film-shaped sintered metal material A1 with a single-sided release film was attached to the adhesive layer side of the adhesive layer-attached substrate (1). The release film was then removed from the film-shaped sintered metal material A1, and the exposed surface of the protective film-forming film with a single-sided release film obtained above was attached to the exposed surface of the resulting film-shaped sintered metal material A1, to prepare a sample for measuring the adhesive strength of the interface (Y) (measurement sample type 1). In addition, a film-like metal baked material A1 with a one-sided release film was attached to the adhesive layer side of the adhesive layer-attached substrate (1) to prepare a sample (measurement sample type 2) for measuring the adhesive strength of the interface (X). Furthermore, a film-like metal sintered material A1 with a one-sided release film was attached to the adhesive layer side of the adhesive layer-attached substrate (2) to prepare a sample (measurement sample type 3) for measuring the adhesive strength between the protruding electrode and the metal sintered material layer. The release film was removed from each sample before measurement.

[0263] <Example 2> A composite sheet for forming a protective film and each sample were produced in the same manner as in Example 1, except that the film-shaped sintered metal material A1 was changed to the film-shaped sintered metal material A2.

[0264] Example 3 A composite sheet for forming a protective film and each sample were produced in the same manner as in Example 1, except that the film-shaped sintered metal material A1 was changed to the film-shaped sintered metal material A3.

[0265] Example 4 A composite sheet for forming a protective film and each sample were produced in the same manner as in Example 1, except that the film-shaped sintered metal material A1 was changed to the film-shaped sintered metal material A4.

[0266] <Comparative Example 1> A film-like baked metal material A1 was attached to the surface of the adhesive layer side of the adhesive layer-attached substrate (1) to prepare a composite sheet.

[0267] <Comparative Example 2> A protective film-forming layer was attached to the surface of the substrate (1) with the adhesive layer on which the adhesive layer was formed, to prepare a composite sheet.

[0268] <Configurations of the composite sheets for forming protective films in Examples 1 to 4 and the composite sheets in Comparative Examples 1 and 2> Example 1: Base material / buffer layer / adhesive layer / film-shaped metal baked material A1 (metal baked material layer A1) / protective film forming layer / release film Example 2: Base material / buffer layer / adhesive layer / film-shaped metal baked material A2 (metal baked material layer A2) / protective film forming layer / release film Example 3: Base material / buffer layer / adhesive layer / film-shaped metal baked material A3 (metal baked material layer A3) / protective film forming layer / release film Example 4: Base material / buffer layer / adhesive layer / film-shaped metal baked material A4 (metal baked material layer A4) / protective film forming layer / release film Comparative Example 1: Substrate / Adhesive layer / Film-shaped metal baked material A1 (metal baked material layer A1) / Release film Comparative Example 2: Substrate / Adhesive Layer / Protective Film-Forming Layer / Release Film

[0269] [evaluation] In this example, the following evaluations 1 to 6 were carried out.

[0270] <Evaluation 1: Measurement of adhesive strength at interface (Y)> Measurement sample type 1 of Examples 1 to 4 was cut to a width of 10 mm, and the release film protecting the protective film forming layer was peeled off from the cut sample. Then, measurement sample type 1 was attached to the mirror surface of a silicon wafer using an attachment device. The surface of measurement sample type 1 attached to the silicon wafer was the surface on the protective film forming layer side. The laminating device used was a roller type laminator (manufactured by Lintec Corporation, product name "RAD-3520 F / 12"), and lamination was carried out under the following laminating conditions. (Attachment conditions) Table temperature: 70℃ Application speed: 0.3m / s - Application pressure: 0.3MPa Roller application height: 0 μm The silicon wafer was then fixed to a universal tensile tester (manufactured by Orientec Co., Ltd., product name "Tensilon UTM-4-100"), and the layers other than the protective film forming layer (substrate, adhesive layer, and fired metal material layer) were then pulled from the protective film forming layer in a 180° direction at a pulling rate of 100 mm / min in accordance with JIS Z0237:2009 under conditions of 23°C and 50% RH, and the adhesive strength was measured (unit: N / 10 mm) when peeling at the interface (Y) leaving only the protective film forming layer remaining from the measurement sample type 1 fixed to the silicon wafer.

[0271] <Evaluation 2: Evaluation of adhesive strength at interface (X)> Measurement sample type 2 of Examples 1 to 4 and Comparative Example 1 was cut to a width of 10 mm, and after the release film was peeled off from the cut sample, measurement sample type 2 was attached to a copper plate using an attachment device. The surface of measurement sample type 2 attached to the copper plate was the surface on the fired metal material layer side. The laminating device used was a roller type laminator (manufactured by Lintec Corporation, RAD-3520 F / 12), and lamination was carried out under the following laminating conditions. (Attachment conditions) Table temperature: 70℃ Application speed: 0.3m / s - Application pressure: 0.3MPa Roller application height: 0 μm The copper plate was then fixed to a universal tensile tester (manufactured by Orientec Co., Ltd., product name "Tensilon UTM-4-100"). Next, the layers other than the baked metal material layer (substrate and adhesive layer) from the adhesive strength measurement sample (Type 2) at interface (X) were pulled at a 180° direction at a pulling rate of 100 mm / min under conditions of 23°C and 50% RH in accordance with JIS Z0237:2009, and the adhesive strength when only the baked metal material layer was left and peeled off at interface (X) was measured (unit: N / 10 mm).

[0272] <Evaluation 3: Evaluation of adhesive strength between protruding electrodes and fired metal material layer> Measurement sample type 2 was changed to measurement sample type 3, and it was attached to a copper plate in the same manner as in Evaluation 2. The copper plate was then fixed to a universal tensile testing machine (manufactured by Orientec Co., Ltd., product name "Tensilon UTM-4-100"). Next, measurement sample type 3 was pulled in a 180° direction at a pulling rate of 100 mm / min in accordance with JIS Z0237:2009 under conditions of a temperature of 23°C and 50% RH, and the adhesive strength between the copper and the fired metal material layer was measured (unit: N / 10 mm). Note that the projecting electrode is often made of copper, and this value can be interpreted as the adhesive strength between the projecting electrode and the fired metal material layer.

[0273] <Evaluation 4: Evaluation of the cleavability of the metal baked material layer> After peeling off the release film protecting the protective film forming layer of the composite sheet for forming a protective film in Examples 1 to 4, the composite sheet for forming a protective film was attached to the pillar formation surface of a semiconductor wafer having Cu pillars using an attachment device. The surface of the composite sheet for forming a protective film that was attached to the pillar formation surface of the semiconductor wafer having pillars was the surface on the protective film forming layer side. The specifications of the semiconductor wafer having pillars are as follows: (Specifications) Wafer size: 8 inches Cu pillar height: 40 μm Cu pillar diameter: 20 μm Distance between pillars: 80μm The laminating device used was a roller type laminator (manufactured by Lintec Corporation, product name "RAD-3520 F / 12"), and lamination was carried out under the following laminating conditions. (Attachment conditions) Table temperature: 70℃ ·Application speed: 3mm / s - Application pressure: 0.5MPa Roller application height: 0μm

[0274] Thereafter, the wafer was attached to a table using a tape remover RAD-3010 manufactured by Lintec, and peeled off at the interface (Y) under the following conditions to evaluate the cleavability of the fired metal material layer. Table temperature: 23°C Peeling speed: Table: 1mm / sec Arm: 1mm / sec When peeling, the table and arm were moved in opposite directions at the same speed (both input values ​​were positive. The relative peeling speed was 2 mm / sec). The evaluation criteria were as follows, with a rating of 0 and a rating of △ being considered a pass. Evaluation: At any position on the wafer surface, the metal sintered material layer was fractured due to separation at the interface (Y), and while the metal sintered material layer remained on the top of the Cu pillar, the metal sintered material layer that was not in contact with the top of the Cu pillar was peeled off along with the adhesive layer. Evaluation: △: There were areas in the wafer where the fracture toughness of the metal sintered material layer was poor due to separation at the interface (Y) in part or all of the wafer surface. Specifically, during separation at the interface (Y), cracks occurred due to cohesive failure or the like in a direction approximately perpendicular to the thickness direction of the metal sintered material layer, resulting in cases where the metal sintered material layer remained at the top of the Cu pillar but was thinner (i.e., cases where the thickness of the joint formed by the metal sintered material layer was thinner at the top of some Cu pillars) or where the metal sintered material layer remained between the tops of adjacent Cu pillars. · Evaluation ×: In a part of the wafer surface, separation at the interface (Y) resulted in poor cleavability of the fired metal material layer, and the metal layer was absent from part or all of the top of the Cu pillar.

[0275] <Evaluation 5: Conductivity evaluation> After evaluation 4, the sample was divided into individual chips. The resulting semiconductor chips with protective films were then bonded to a wiring substrate to prepare a bonding sample. The wiring substrate was a glass epoxy substrate with copper wiring (width: 35 μm, spacing between adjacent wiring: 35 μm). The glass epoxy substrate was 30 mm wide x 30 mm long and 2 mm thick. The bonding sample was then sintered at 350°C, 10 MPa, and for 3 hours to prepare a sample for conductivity evaluation. Then, for the samples for conductivity evaluation, the resistance between the wiring of the board was measured and a continuity test was performed. A resistance measuring device (Card HiTester 3244-60, manufactured by Hioki E.E. Corporation) was used to measure the resistance. The conductivity was evaluated based on the following criteria: when the resistance could be measured in this continuity test (i.e., when the device had a predetermined resistance value), it was evaluated as ◯, and when the resistance value showed a maximum value (i.e., when the device had a significantly higher resistance value than the predetermined resistance value), it was evaluated as ×. A rating of ◯ was considered a pass.

[0276] <Evaluation 6: Evaluation of the bonding strength of the bonded body> For the conductivity evaluation sample (Comparative Example 1) obtained above, a force was applied in a direction parallel to the chip surface at a speed of 200 μm / s in an environment of 23°C. A stainless steel plate-shaped pressing means was used to apply the force, and the tip of the pressing means was positioned 20 μm above the surface of the substrate in the bonded body so that the pressing means did not come into contact with the substrate. The maximum force applied until the metal sintered layer was destroyed or peeled off from the substrate was measured, and this measured value was used as the shear strength of the bonded body. The same shear strength was measured for all other samples for conductivity evaluation, and the average value was finally adopted as the shear strength of the bonded structure. The bond strength of the bonded structure was then evaluated according to the following criteria. A rating of ◯ was considered to be acceptable. The results are shown in Table 1. (Evaluation criteria) ◯: The shear strength is equal to or greater than that of Comparative Example 1, and the bonding strength is particularly high. ×: Shear strength is lower than Comparative Example 1.

[0277] The evaluation results are shown in Table 1.

[0278] [Table 1]

[0279] From Table 1, we can see the following: It can be seen that by using the composite sheets for forming a protective film of Examples 1 to 4, the sintered metal material layer has excellent cleavability, and electrical connection between the wiring on the substrate and the protruding electrodes (pillars) can be sufficiently ensured. From this, it can be seen that when the composite sheets for forming a protective film of Examples 1 to 4 are separated at the interface (Y), the force applied to the sintered metal material layer at that time causes the sintered metal material layer to cleave, and the metal sintered metal layer in contact with the protective film forming layer can be easily peeled off from the protective film forming layer, and the metal sintered metal layer in contact with the top of the protruding electrode remains without being peeled off from the top of the protruding electrode, resulting in sufficient electrical connection between the wiring on the substrate and the protruding electrodes (pillars). Therefore, from the results shown in this example, it can be seen that it is possible to easily form a joint made of a joining material for connecting components to be joined. [Explanation of symbols]

[0280] 1a, 1b Composite sheet for forming protective film 10 Base material 11 Adhesive layer 12. Metal baking layer 13 Protective film forming layer 14 Buffer layer 20 Semiconductor wafers 21 Protruding electrode 30 Semiconductor wafer with protective film forming layer 40 Semiconductor chip with protective film 60 boards 61 Wiring

Claims

1. A composite sheet for forming a protective film for forming a protective film on a protruding electrode-formed surface of a member with protruding electrodes, The adhesive layer includes a substrate, a pressure-sensitive adhesive layer, a fired metal material layer, and a protective film-forming layer in this order; An interface (X) where the pressure-sensitive adhesive layer and the fired metal material layer are in direct contact with each other; The composite sheet for forming a protective film has an interface (Y) where the fired metal material layer and the protective film forming layer are in direct contact with each other.

2. The composite sheet for forming a protective film according to claim 1 , wherein the adhesive strength of the interface (Y) is smaller than the adhesive strength of the interface (X).

3. 3. The composite sheet for forming a protective film according to claim 2, wherein the adhesive strength between the bump electrode and the fired metal material layer is greater than the adhesive strength at the interface (X).

4. 3. The composite sheet for forming a protective film according to claim 1, wherein the fired metal material layer has a thickness of less than 100 [mu]m.

5. The composite sheet for forming a protective film according to claim 1 or 2, further comprising a buffer layer between the substrate and the pressure-sensitive adhesive layer.

6. a step of attaching the protective film forming layer of the composite sheet for forming a protective film according to claim 1 or 2 to a projecting electrode forming surface of a member with projecting electrodes on which projecting electrodes are formed; separating the composite sheet for forming a protective film at an interface (Y) to prepare a laminate of the member with protruding electrodes and the protective film forming layer.

7. 7. The method for manufacturing a semiconductor device according to claim 6, further comprising the step of connecting the electrodes of the substrate and the projecting electrodes of the laminate by sintering.

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