Film for forming a protective film, composite sheet for forming a protective film, and method for manufacturing a semiconductor device.

Abstract

By placing the protective film-forming film and the protruding electrode-forming surface of the member with the protruding electrode facing each other and simultaneously pressing the entire surface of the member with the protruding electrode into the protective film-forming film, a protective film-forming film is provided that suppresses the generation of air bubbles in the center of the member while exhibiting excellent filling properties for the protruding electrode-forming surface when the protective film-forming film is applied to the protruding electrode-forming surface. [Solution] A protective film-forming film is used to form a protective film on the protruding electrode-forming surface of a member with a protruding electrode, wherein the protective film-forming film has a storage modulus G' of 3.5 MPa or less at 30°C before curing, and is used by placing the protective film-forming film and the protruding electrode-forming surface of the member with the protruding electrode facing each other and simultaneously pressing the entire surface of the member with the protruding electrode into the protective film-forming film, thereby attaching the protective film-forming film to the protruding electrode-forming surface.

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] In recent years, semiconductor devices have been manufactured using a mounting method known as the face-down method. In the face-down method, a semiconductor chip with bumps on its circuit surface and a substrate for mounting the semiconductor chip are stacked so that the circuit surface of the semiconductor chip and the substrate face each other, thereby mounting the semiconductor chip onto the substrate. Typically, these semiconductor chips are obtained by slicing a semiconductor wafer, which has bumps on its circuit surface, into individual pieces.

[0003] Incidentally, semiconductor wafers equipped with protruding electrodes such as bumps may have a protective film provided to protect the junction between the protruding electrode and the semiconductor wafer (hereinafter also referred to as the "base portion"). For example, in Patent Document 1, a laminate in which a substrate, an adhesive layer, and a thermosetting resin layer are stacked in this order is pressed and attached to the bump-forming surface of a semiconductor wafer having bumps, with the thermosetting resin layer as the bonding surface, and then the thermosetting resin layer is heated and cured to form a protective film. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2015-092594 [Overview of the project] [Problems that the invention aims to solve]

[0005] In recent years, various methods for applying film have been proposed, one of which involves simultaneously pressing the entire surface of the object to be applied to the film (hereinafter also referred to as the "full surface pressure pressing method"). However, the full-surface pressure pressing method has the disadvantage that it cannot release air bubbles generated during application by following the movement of the rollers during the application process, as is done with roller-type laminators. Therefore, if the object to be attached is, for example, a member with protruding electrodes, and the density of the protruding electrodes is sparse within the surface where the protruding electrodes are formed, or if there are extensive areas where no protruding electrodes are present (especially if such areas are located in the center of the surface where the protruding electrodes are formed), air bubbles are likely to form during attachment. As a result, these air bubbles may expand and burst during heating in a later process, potentially causing poor connection with the substrate.

[0006] Therefore, the present invention aims to provide a protective film forming film, a protective film forming composite sheet, and a method for manufacturing a semiconductor device, which exhibit excellent filling properties onto the protruding electrode forming surface while suppressing the generation of air bubbles, even when employing an application method in which the protective film forming film and the protruding electrode forming surface of the member with protruding electrodes are faced each other and the entire surface of the member with protruding electrodes is simultaneously pressed into the protective film forming film to adhere the protective film forming film to the protruding electrode forming surface. [Means for solving the problem]

[0007] The present invention provides the following [1] to [9]. [1] A protective film-forming film used to form a protective film on the surface of a protruding electrode of a member with a protruding electrode, The protective film is a curable resin film (x) having a storage modulus G' of 3.5 MPa or less at 30°C before curing. [2] The protective film-forming film according to [1] above, wherein the curable resin film (x) has a breaking energy of 2.6 J or less at 23°C before curing. [3] The protective film-forming film according to [1] or [2] above, wherein the curable resin film (x) has a storage modulus G' of 1,000 Pa or more at 30°C before curing. [4] The protective film forming film according to any one of [1] to [3] above, wherein the curable resin film (x) is a thermosetting resin film (x1). [5] The thermosetting resin film (x1) is a protective film for forming a protective film as described in [4] above, wherein the thermosetting resin film (x1) contains a flexible epoxy resin. [6] A protective film forming film according to any one of [1] to [5] above, wherein the protective film forming film and the protruding electrode forming surface of the member with the protruding electrode are placed facing each other, and the entire surface of the member with the protruding electrode is pressed simultaneously into the protective film forming film, thereby attaching the protective film forming film to the protruding electrode forming surface. [7] A composite sheet for forming a protective film, wherein the protective film-forming film and a support sheet described in any one of [1] to [6] above are laminated together. [8] A method for manufacturing a semiconductor device, comprising forming a protective film on the protruding electrode forming surface of a member with a protruding electrode using a protective film described in any one of [1] to [6] above, Step (S1) involves placing the protective film-forming film and the protruding electrode-forming surface of the member with the protruding electrode facing each other, and simultaneously pressing the entire surface of the member with the protruding electrode into the protective film-forming film, thereby attaching the protective film-forming film to the protruding electrode-forming surface. The process of curing the protective film (S2), A method for manufacturing a semiconductor device, including the method described above. [9] The method for manufacturing a semiconductor device according to [8] above, wherein the member with a protruding electrode is a semiconductor chip with a protruding electrode. [Effects of the Invention]

[0008] According to the present invention, by causing the protective film-forming film and the protruding electrode-forming surface of the member with protruding electrodes to face each other, and simultaneously pressing the entire surface of the member with protruding electrodes into the protective film-forming film, it is possible to provide a protective film-forming film, a protective film-forming composite sheet, and a method for manufacturing a semiconductor device that exhibit excellent filling performance to the protruding electrode-forming surface while suppressing the generation of air bubbles, even when employing a bonding method in which the protective film-forming film is bonded to the protruding electrode-forming surface. Brief Description of the Drawings

[0009] [Figure 1] It is a schematic cross-sectional view showing an example of the protective film-forming composite sheet of the present embodiment. [Figure 2] It is a schematic cross-sectional view showing another example of the protective film-forming composite sheet of the present embodiment. [Figure 3] It is a schematic cross-sectional view showing still another example of the protective film-forming composite sheet of the present embodiment. [Figure 4] It is a schematic cross-sectional view showing a part of the method for manufacturing the semiconductor device of the present embodiment. Modes for Carrying Out the Invention

[0010] In the present specification, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are values in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method, and specifically are values measured based on the methods described in the Examples.

[0011] In the present specification, for preferred numerical ranges (for example, ranges such as content), the lower limit values and upper limit values described stepwise can be independently combined. For example, from the description "preferably 10 to 90, more preferably 30 to 60", the "preferred lower limit (10)" and the "more preferred upper limit (60)" can be combined to form "10 to 60".

[0012] In the present specification, "energy ray" means an electromagnetic wave or a charged particle beam that has an energy quantum. Examples of energy rays include ultraviolet rays, radiation, electron beams, and the like. Ultraviolet rays can be irradiated using an electrodeless lamp, a high-pressure mercury lamp, a metal halide lamp, a xenon lamp, a black light, an LED lamp, or the like. Electron beams can be irradiated with those generated by an electron beam accelerator or the like. Further, in the present specification, "energy ray curable" means a property of curing upon irradiation with an energy ray, and "thermosetting" means a property of curing upon heating.

[0013] In the present specification, for example, "(meth)acrylic acid" indicates both "acrylic acid" and "methacrylic acid", and the same applies to other similar terms.

[0014] In the present specification, the "circuit surface" of a semiconductor wafer and a semiconductor chip refers to the surface on which a circuit is formed, and the "back surface" of a semiconductor wafer and a semiconductor chip refers to the surface opposite to the circuit surface.

[0015] In the present specification, the "thickness" of a certain object means the thickness of the entire object, and for example, when the object is composed of a plurality of layers, it means the total thickness of all layers constituting the object. Note that the "thickness" of an object in the present specification, unless otherwise specified, means the average value of thicknesses measured at 5 randomly selected positions on the object, and can be obtained using a constant-pressure thickness measuring instrument in accordance with JIS K 7130:1999.

[0016] In the present specification, "solid content" or "active ingredient" refers to components excluding diluent solvents such as water and organic solvents, among the components contained in the target composition.

[0017] The mechanism of action described in the present specification is speculative, and does not limit the mechanism by which the effects of the present invention are achieved.

[0018] In order to make the features of the present invention easier to understand, the drawings may show enlarged versions of key parts for convenience, and the dimensional ratios of each component may not be the same as in reality.

[0019] [Aspects of the protective film-forming film according to this embodiment] The protective film-forming film of this embodiment is a protective film-forming film used to form a protective film on the protruding electrode-forming surface of a member with a protruding electrode, and the protective film-forming film is a curable resin film (x) having a storage modulus G' of 3.5 MPa or less at 30°C before curing. The inventors, in an effort to solve the above problems, have found that the storage modulus G' at 30°C before curing of the curable resin film (x) used as a protective film-forming film greatly affects the adhesion (adhesion in the full-surface pressure pressing method) when the protective film-forming film is attached to the protruding electrode-forming surface by facing the protective film-forming film and simultaneously pressing the entire surface of the protruding electrode-forming member into the protective film-forming film. Furthermore, the inventors have found that if the storage modulus G' at 30°C before curing of the curable resin film (x) used as a protective film-forming film is 3.5 MPa or less, the adhesion in the full-surface pressure pressing method is good. Furthermore, if a curable resin film (x) with a storage modulus G' at 30°C before curing exceeds 3.5 MPa is used, the adhesive properties in the full-surface pressure pressing method will deteriorate, and problems such as the formation of air bubbles will be more likely to occur.

[0020] Here, from the viewpoint of making it easier to improve the adhesiveness in the full-surface pressure pressing method, the storage modulus G' of the curable resin film (x) at 30°C before curing is preferably 3.0 MPa or less, more preferably 2.5 MPa or less, and even more preferably 1.6 MPa or less. Furthermore, from the viewpoint of suppressing the leakage of the curable resin film (x), the storage modulus G' of the curable resin film (x) at 30°C before curing is preferably 1,000 Pa or more. The storage modulus G' of the curable resin film (x) at 30°C before curing can be measured by the method described in the examples. Furthermore, in this embodiment, "before curing" means the state before the curable resin film (x) is subjected to thermosetting treatment or energy ray curing treatment. For example, a curable resin composition (x1) described later that has been dried (drying temperature 70-130°C, drying time 10 seconds-5 minutes) is also included in the "before curing" thermosetting resin film (x).

[0021] Furthermore, from the viewpoint of further improving the adhesiveness in the full-surface pressure pressing method and making it easier to improve the filling ability of the curable resin film (x) into the protruding electrode formation surface, the breaking energy at 23°C before curing is preferably 2.6 J or less, more preferably 2.0 J or less, and even more preferably 1.0 J or less. The fracture energy of the curable resin film (x) at 23°C before curing can be measured by the method described in the examples.

[0022] The storage modulus G' (and furthermore, the fracture energy at 23°C) of the curable resin film (x) before curing at 30°C can be adjusted to the above range by adjusting one or both of the types and contents of components contained in the curable resin composition for forming the curable resin film (x). Here, an effective method for adjusting the storage modulus G' (and furthermore, the fracture energy at 23°C) of the curable resin film (x) at 30°C before curing to the above range is, for example, to use a flexible epoxy as the thermosetting component (B) described later. However, the method for controlling the storage modulus G' (and furthermore, the fracture energy at 23°C) of the curable resin film (x) at 30°C is not limited to these.

[0023] The following describes in detail the curable resin film (x) used as the protective film-forming film in this embodiment, including the method for adjusting the storage modulus G' (and furthermore, the fracture energy at 23°C) of the curable resin film (x) at 30°C before curing.

[0024] <Composition of curable resin film (x)> The curable resin film (x), upon curing, becomes a highly protective film with excellent protective properties, such as protection of the surface on which the protruding electrode is formed (especially the protection of the base of the bump if the protruding electrode is a bump) and impact resistance. The curable resin film (x) may be thermosetting, which hardens by heating, or energy-ray curable, which hardens by energy ray irradiation. However, from the viewpoint of ease of adjusting the storage modulus G' at 30°C (and furthermore, the fracture energy at 23°C), the thermosetting resin film (x1) is preferred. The thermosetting resin film (x1) and the energy ray curable resin film (x2) will be described below.

[0025] (Thermosetting resin film (x1)) The thermosetting resin film (x1) contains a polymer component (A) and a thermosetting component (B). The thermosetting resin film (x1) is formed, for example, from a thermosetting resin composition (x1-1) containing a polymer component (A) and a thermosetting component (B). Polymeric component (A) is a component that can be considered to have been formed by a polymerization reaction of polymerizable compounds. Thermosetting component (B) is a component that can undergo a curing (polymerization) reaction triggered by heat. This curing (polymerization) reaction includes polycondensation reactions.

[0026] (Polymer component (A)) The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) contain a polymer component (A). Polymer component (A) is a polymer compound used to impart film-forming properties, flexibility, and other characteristics to the thermosetting resin film (x1). Polymer component (A) may be used alone or in combination of two or more types. When two or more polymer components (A) are used in combination, the combination and ratio can be arbitrarily selected.

[0027] Examples of polymer components (A) include acrylic resins, polyarylate resins, polyacetal resins, 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 polyacetal resins are preferred, with polyacetal resins being more preferred.

[0028] -Acrylic resin- Examples of acrylic resins include well-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. Having a weight-average molecular weight of the acrylic resin above the lower limit mentioned above makes it easier to improve the shape stability (stable over time during storage) of the thermosetting resin film (x1). Also, having a weight-average molecular weight of the acrylic resin below the upper limit mentioned above makes it easier for the thermosetting resin film (x1) to conform to the uneven surface of the adherend, for example, making it easier to suppress the generation of voids between the adherend and the thermosetting resin film (x1). Therefore, the coverage of the surface on which protruding electrodes are formed is improved, and the ability to fill grooves that these surfaces may have is also improved.

[0029] 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 adhesiveness and handling properties of the thermosetting resin film (x1).

[0030] 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, etc.

[0031] Examples of (meth)acrylic acid esters that constitute acrylic resins 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) Alkyl methacrylates 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), in which the alkyl group constituting the alkyl ester has a chain structure with 1 to 18 carbon atoms; Cycloalkyl esters of (meth)acrylates, such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate; (meth)acrylate aralkyl esters such as benzyl (meth)acrylate; (meth)acrylate dicyclopentenyl ester and other cycloalkenyl (meth)acrylates; (meth)acrylate cycloalkenyloxyalkyl esters such as (meth)acrylate dicyclopentenyloxyethyl ester; (meth)acrylimide; Glycidyl group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate; 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 other hydroxyl group-containing (meth)acrylate esters; Examples include (meth)acrylic acid esters containing substituted amino groups, such as N-methylaminoethyl (meth)acrylate. In this specification, "substituted amino group" means a group in which one or two hydrogen atoms of an amino group are replaced by a group other than a hydrogen atom. Among these, from the viewpoint of film-forming properties of the thermosetting resin film (x1) and the adherence of the thermosetting resin film (x1) to the protruding electrode forming surface, it is preferable that the alkyl group constituting the alkyl ester is a copolymer of (meth)acrylate alkyl ester having a chain structure with 1 to 18 carbon atoms, glycidyl group-containing (meth)acrylate ester, and hydroxyl group-containing (meth)acrylate ester; it is more preferable that the alkyl group constituting the alkyl ester is a copolymer of (meth)acrylate alkyl ester having a chain structure with 1 to 4 carbon atoms, glycidyl group-containing (meth)acrylate ester, and hydroxyl group-containing (meth)acrylate ester; and it is even more preferable that it is a copolymer of butyl acrylate, methyl acrylate, glycidyl acrylate, and 2-hydroxyethyl acrylate.

[0032] The acrylic resin may be obtained by copolymerizing one or more monomers selected from, for example, (meth)acrylic acid ester, (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, and N-methylolacrylamide, in addition to (meth)acrylic acid ester.

[0033] The monomers that make up the acrylic resin may be used individually or in combination of two or more. When the monomers that make up the acrylic resin are two or more, their combination and ratio can be arbitrarily selected.

[0034] -Polyarylate resin- Examples of the polyarylate resin in polymer component (A) include those that are well known. Examples of polyarylate resins include resins whose basic structure is the polycondensation of a divalent phenol with a dibasic acid such as phthalic acid or a carboxylic acid. Among these, polycondensates of bisphenol A and phthalic acid, poly-4,4'-isopropylidenediphenylene terephthalate / isophthalate copolymers, and their derivatives are preferred. Furthermore, by including polyarylate resin in the polymer component (A), it becomes easier to adjust the glass transition temperature (Tg) of the thermosetting resin film (x1) before curing to 40°C or below.

[0035] -Acetal resin- Examples of the polyacetal resin in polymer component (A) include those that are well known. Among these, preferred polyacetal resins include, for example, polyvinyl formal and polyvinyl butyral, with polyvinyl butyral being the most preferred. Examples of polyvinyl butyral include those having constituent units represented by the following formulas (i)-1, (i)-2, and (i)-3.

[0036] [ka]

[0037] (In the formula, l, m, and n are each an independent integer greater than or equal to 1.)

[0038] The weight-average molecular weight (Mw) of the polyvinyl acetal resin (preferably polyvinyl butyral) is preferably 5,000 to 200,000, more preferably 8,000 to 100,000, even more preferably 8,000 to 50,000, and even more preferably 10,000 to 35,000. Having a weight-average molecular weight of the polyvinyl acetal resin (preferably polyvinyl butyral) above the lower limit of the above-mentioned values ​​makes it easier to improve the shape stability (stable over time during storage) of the thermosetting resin film (x1). Furthermore, having a weight-average molecular weight of the polyvinyl acetal resin (preferably polyvinyl butyral) below the upper limit of the above-mentioned values ​​makes it easier for the thermosetting resin film (x1) to conform to the uneven surface of the adherend, for example, making it easier to suppress the generation of voids between the adherend and the thermosetting resin film (x1). Therefore, the coating properties on the surface where the protruding electrode is formed are improved, and the ability to embed into any irregularities that the material may have is also easily enhanced.

[0039] The glass transition temperature (Tg) of the polyvinyl acetal resin (preferably polyvinyl butyral) is preferably 40 to 80°C, and more preferably 50 to 70°C, from the viewpoint of film-forming properties of the thermosetting resin film (x1) and the protrusion of the tops of the protruding electrodes on the protruding electrode forming surface. Herein, in this specification, "the ability of the top of the protruding electrode to penetrate the thermosetting resin film (x1) when the thermosetting resin film (x1) is attached to the surface on which the protruding electrode is formed" refers to the ability of the top of the protruding electrode to penetrate the thermosetting resin film (x1), and is also referred to as "the ability of the top of the protruding electrode to penetrate".

[0040] The ratio of three or more monomers that make up the polyvinyl acetal resin (preferably polyvinyl butyral) can be arbitrarily selected.

[0041] In the thermosetting resin film (x1) and the thermosetting resin composition (x1-1), the content of polymer component (A) is preferably 2.0 to 30% by mass, more preferably 2.3 to 25% by mass, and even more preferably 2.5 to 15% by mass, based on the total amount of active ingredients.

[0042] Polymer component (A) may also correspond to thermosetting component (B). In this embodiment, if thermosetting resin composition (x1) and thermosetting resin composition (x1-1) contain components that correspond to both polymer component (A) and thermosetting component (B), thermosetting resin composition (x1) and thermosetting resin composition (x1-1) are considered to contain both polymer component (A) and thermosetting component (B).

[0043] (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 that cures the thermosetting resin film (x1) to form a hard, cured resin film. The thermosetting component (B) may be used alone or in combination of two or more types. If there are two or more types of thermosetting component (B), their combination and ratio can be arbitrarily selected.

[0044] Examples of thermosetting component (B) include epoxy thermosetting resins, thermosetting polyimides, polyurethanes, unsaturated polyesters, and silicone resins. Among these, epoxy thermosetting resins are preferred. When thermosetting component (B) is an epoxy thermosetting resin, the protective properties of the cured resin film and the protrusion of the top of the protruding electrode are improved, and warping of the cured resin film can be suppressed.

[0045] Epoxy thermosetting resins consist of an epoxy resin (B1) and a thermosetting agent (B2). Epoxy thermosetting resins may be used individually or in combination of two or more types. When two or more epoxy thermosetting resins are used, their combination and ratio can be arbitrarily selected.

[0046] -Epoxy resin (B1)- While the epoxy resin (B1) is not particularly limited, 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) from the viewpoint of making it easier to exhibit the effects of the present invention. Furthermore, from the viewpoint of making it easier to adjust the storage modulus G' of the thermosetting resin film (x1) at 30°C before curing to 40°C or less, and from the viewpoint of making it easier to adjust the breaking energy at 23°C to 2.6 J or less, it is preferable to use a flexible epoxy resin among liquid epoxy resins. In this specification, "room temperature" refers to 5 to 35°C, preferably 15 to 25°C.

[0047] The liquid epoxy resin is not particularly limited as long as it is liquid at room temperature. Examples include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, glycidyl ester type epoxy resin, biphenyl type epoxy resin, and phenylene skeleton type epoxy resin. Among these, bisphenol A type epoxy resin is preferred. Liquid epoxy resin may be used alone or in combination of two or more types. When two or more types of liquid epoxy resin are used, their combination and ratio can be arbitrarily selected.

[0048] 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 520 g / eq. The epoxy equivalent in this embodiment can be measured in accordance with JIS K 7236:2009.

[0049] As previously mentioned, it is preferable to use a flexible epoxy resin among liquid epoxy resins. In this embodiment, the term "flexible epoxy resin" refers to an epoxy resin into which a flexible skeleton has been introduced. Flexible skeletons in flexible epoxy resins include alkylene groups, alkenylene groups, alkylylene groups, polyoxyalkylene groups, polyoxyalkenylene groups, and polyoxyalkylene groups. The number of carbon atoms in the alkylene group, alkenylene group, and alkynylene group is preferably 1 to 30, more preferably 1 to 15, from the viewpoint of improving the stability of the flexible epoxy resin, facilitating the reduction of the glass transition temperature, and improving the embedding ability of the protruding electrode. Furthermore, the number of carbon atoms in the alkylene group, alkenylene group, and alkylylene group of the polyoxyalkylene group, polyoxyalkynylene group, and polyoxyalkynylene group is preferably 2 to 4, more preferably 3. Furthermore, from the viewpoint of easily adjusting the glass transition temperature (Tg) of the thermosetting resin film (x1) before curing to 40°C or lower, it is preferable that the flexible skeleton in the flexible epoxy resin does not have rigid bonds or skeletons, and it is particularly preferable that it does not have an aromatic ring skeleton. Furthermore, it is preferable that the flexible epoxy resin has the above-mentioned flexible skeleton introduced between the epoxy group and the bisphenol skeleton. More preferably, it is a flexible epoxy resin represented by the following general formula (2). EL 1 -BL 2 -E···(2) In the above general formula (1), E is an epoxy group. B is a bisphenol skeleton (for example, a divalent group obtained by removing a hydrogen atom from the hydroxyl group of bisphenol A). 1 and L 2 Each of these is an independent flexible skeleton as described above. Flexible epoxy resins may be used individually or in combination of two or more types. When two or more flexible epoxy resins are used, their combination and ratio can be arbitrarily selected.

[0050] The solid epoxy resin is not particularly limited as long as it is solid at room temperature. Examples include biphenyl-type epoxy resin, bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, orthocresol novolac epoxy resin, dicyclopentadiene-type epoxy resin, naphthalene-type epoxy resin, anthracene-type epoxy resin, and fluorene-based epoxy resin. Among these, naphthalene-type epoxy resin, dicyclopentadiene-type epoxy resin, and fluorene-based epoxy resin are preferred, and naphthalene-type epoxy resin and dicyclopentadiene-type epoxy resin are more preferred. Solid epoxy resins may be used individually or in combination of two or more types. If two or more types of solid epoxy resins are used, their combination and ratio can be arbitrarily selected.

[0051] The epoxy equivalent of the solid epoxy resin is preferably 150 to 450 g / eq, and more preferably 150 to 400 g / eq.

[0052] The ratio of liquid epoxy resin (xe) to 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 above ratio [(xe) / (ye)] is within the above range, the effects of the present invention can be more easily improved. Furthermore, the content of the above-mentioned flexible epoxy resin in the liquid epoxy resin (XE) is preferably 30% to 100% by mass, more preferably 50% to 100% by mass, and even more preferably 60% to 100% by mass, based on the total amount of liquid epoxy resin (XE).

[0053] The number-average molecular weight of the epoxy resin (B1) is not particularly limited, but from the viewpoint of the curability of the thermosetting resin film (x1) 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.

[0054] -Thermosetting agent (B2)- The thermosetting agent (B2) functions as a curing agent for the epoxy resin (B1). Examples of the thermosetting agent (B2) include compounds having two or more functional groups capable of reacting with epoxy groups in one molecule. Examples of the above functional groups include phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, carboxyl groups, and groups in which an acid group has been converted into an anhydride. It is preferable that the functional group is a phenolic hydroxyl group, an amino group, or a group in which an acid group has been converted into an anhydride, and it is more preferable that the functional group is a phenolic hydroxyl group or an amino group.

[0055] Examples of thermosetting agents (B2) that include phenolic curing agents having phenolic hydroxyl groups include polyfunctional phenolic resins, biphenols, novolac-type phenolic resins, dicyclopentadiene-based phenolic resins, and aralkylphenolic resins. Among the thermosetting 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 phenolic hydroxyl groups are preferred, and novolac-type phenolic resins are more preferred.

[0056] Among the thermosetting agents (B2), the number average molecular weight of the resin components, such as polyfunctional phenolic resins, novolac-type phenolic resins, dicyclopentadiene-based phenolic resins, and aralkylphenolic resins, is preferably 300 to 30,000, more preferably 400 to 10,000, and even more preferably 500 to 3,000. The molecular weight of the non-resin component of the thermosetting agent (B2), such as biphenol or dicyandiamide, is not particularly limited, but is preferably 60 to 500.

[0057] The thermosetting agent (B2) may be used alone or in combination of two or more types. If there are two or more types of thermosetting agent (B2), their combination and ratio can be arbitrarily selected.

[0058] In the thermosetting resin film (x1) and 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, based on 100 parts by mass of epoxy resin (B1). When the content of the thermosetting agent (B2) is above the lower limit, the curing of the thermosetting resin film (x1) proceeds more easily. Furthermore, when the content of the thermosetting agent (B2) is below the upper limit, the moisture absorption rate of the thermosetting resin film (x1) is reduced, and the reliability of the package obtained using the thermosetting resin film (x1) is further improved.

[0059] In the thermosetting resin film (x1) and thermosetting resin composition (x1-1), the content of the thermosetting component (B) (total content of epoxy resin (B1) and thermosetting agent (B2)) is preferably 200 to 10,000 parts by mass, more preferably 300 to 5,000 parts by mass, and even more preferably 400 to 1,000 parts by mass, per 100 parts by mass of the polymer component (A), from the viewpoint of enhancing the protective properties of the cured resin film.

[0060] -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 an ingredient used to adjust the curing rate of the thermosetting resin film (x1). Preferred curing accelerators (C) include, for example, tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole (imidazoles in which one or more hydrogen atoms are substituted with groups other than hydrogen atoms); organophosphines such as tributylphosphine, diphenylphosphine, and triphenylphosphine (phosphines in which one or more hydrogen atoms are substituted with organic groups); 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.

[0061] The curing accelerator (C) may be used alone or in combination of two or more types. If there are two or more types of curing accelerator (C), their combination and ratio can be arbitrarily selected.

[0062] In the thermosetting resin film (x1) and thermosetting resin composition (x1-1), when a curing accelerator (C) is used, the content of the curing accelerator (C) is preferably 0.001 to 10 parts by mass, and more preferably 0.01 to 5 parts by mass, per 100 parts by mass of the content of the thermosetting component (B). When the content of the curing accelerator (C) is above the lower limit, the effect of using the curing accelerator (C) is more easily obtained. Furthermore, when the content of the curing accelerator (C) is below the upper limit, for example, the effect of suppressing the migration and segregation of highly polar curing accelerators (C) to the adhesive interface side with the adherend in the thermosetting resin film (x1) under high temperature and high humidity conditions is enhanced, and the reliability of the package obtained using the thermosetting resin film (x1) is further improved.

[0063] -Filling material (D)- The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a filler (D). By including a filler (D) and satisfying the above parameters, the chipping suppression of the cured resin film obtained by curing the thermosetting resin film (x) can be easily improved. Furthermore, by including the filler (D), it becomes easier to adjust the coefficient of thermal expansion of the cured resin film obtained by curing the thermosetting resin film (x) to an appropriate range, thereby further improving the reliability of the package obtained using the thermosetting resin film (x1). In addition, by including the filler (D) in the thermosetting resin film (x1), it is also possible to reduce the moisture absorption rate of the cured resin film and improve its heat dissipation.

[0064] The filler (D) may be either an organic filler or an inorganic filler, but it is preferably an inorganic filler or an organic / inorganic hybrid filler. Preferred inorganic fillers include, for example, powders such as silica, talc, calcium carbonate, and boron nitride; beads formed from these inorganic fillers in a spherical shape; surface modified products of these inorganic fillers; single crystal fibers of these inorganic fillers; and glass fibers. Preferred organic / inorganic hybrid fillers include, for example, component-mixed fillers such as silica-acrylic composite particles (e.g., Soliostar manufactured by Nippon Shokubai); and composite fillers incorporating inorganic fine particles with organic materials. Among these, inorganic fillers are preferred, and among inorganic fillers, silica is preferred.

[0065] The filler (D) may be used alone or in combination of two or more types. If there are two or more types of filler (D), their combination and ratio can be selected arbitrarily.

[0066] In the thermosetting resin film (x1) and thermosetting resin composition (x1-1), when a filler (D) is used, the content of the filler (D) is preferably 5 to 50% by mass, more preferably 7 to 40% by mass, and even more preferably 10 to 30% by mass, based on the total amount of the active ingredient, from the viewpoint of suppressing the peeling of the cured resin film from the chip due to thermal expansion and thermal contraction.

[0067] The average particle size of the filler (D) is preferably 500 nm or less, more preferably 5 to 300 nm, and particularly preferably 10 to 100 nm. In this specification, the particle size of the filler (D) refers to the arithmetic mean particle size obtained by randomly selecting and measuring the particle sizes of multiple primary particles of the filler (D) observed with an electron microscope, and then calculating the average value of these measurements.

[0068] -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 an energy-ray curable resin (E), allowing its properties to be altered by irradiation with energy rays.

[0069] Energy-ray curable resin (E) is obtained by polymerizing (curing) an energy-ray curable compound. Examples of energy-ray curable compounds include a polymer (e1) having energy-ray curable groups and a weight-average molecular weight of 80,000 to 2,000,000, and a compound (e2) having energy-ray curable groups and a molecular weight of 100 to 80,000. The polymer (e1) may be at least partially crosslinked with a crosslinking agent, or it may not be crosslinked.

[0070] (A polymer (e1) having energy-ray curable groups and a weight-average molecular weight of 80,000 to 2,000,000) Examples of polymers (e1) having energy ray curable groups and a weight-average molecular weight of 80,000 to 2,000,000 include acrylic resins (e1-1) formed by an addition reaction between an acrylic polymer (e11) having a functional group that can react with a group of another compound, and an energy ray curable compound (e12) having a group that reacts with the functional group and an energy ray curable group such as an energy ray curable double bond.

[0071] Examples of functional groups that can react with groups of 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 replaced by a group other than a hydrogen atom), and epoxy groups. However, in terms of preventing corrosion of circuits such as semiconductor wafers and semiconductor chips, it is preferable that the functional group is a group other than a carboxyl group. Among these, the functional group is preferably a hydroxyl group.

[0072] • Acrylic polymer having functional groups (e11) Examples of the acrylic polymer (e11) having the functional group include those obtained by copolymerizing an acrylic monomer having the functional group with an acrylic monomer not having the functional group, and those obtained by copolymerizing monomers other than acrylic monomers (non-acrylic monomers) in addition to these monomers. Furthermore, the acrylic polymer (e11) may be a random copolymer or a block copolymer.

[0073] Examples of acrylic monomers having the aforementioned functional groups include hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, substituted amino group-containing monomers, epoxy group-containing monomers, and the like.

[0074] Examples of the hydroxyl group-containing monomers 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 include hydroxyalkyl (meth)acrylates, vinyl alcohol, allyl alcohol, and other non-(meth)acrylic unsaturated alcohols (unsaturated alcohols that do not have a (meth)acryloyl skeleton).

[0075] Examples of the carboxyl 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 ethylenically unsaturated dicarboxylic acids; and carboxyalkyl esters of (meth)acrylic acid such as 2-carboxyethyl methacrylate.

[0076] The acrylic monomer having the aforementioned functional group is preferably a hydroxyl group-containing monomer or a carboxyl group-containing monomer, and more preferably a hydroxyl group-containing monomer.

[0077] The acrylic polymer (e11) may consist of only one acrylic monomer having the functional group, or two or more monomers. If there are two or more monomers, their combination and ratio can be arbitrarily selected.

[0078] Examples of acrylic monomers that do not have the aforementioned functional groups 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 methyl (meth)acrylate. Examples of alkyl esters include isononyl, 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, octadecyl ((meth)acrylate) (stearyl (meth)acrylate), etc., in which the alkyl group constituting the alkyl ester has a chain structure with 1 to 18 carbon atoms.

[0079] Furthermore, examples of acrylic monomers that do not have the aforementioned functional groups include alkoxyalkyl group-containing (meth)acrylic acid esters such as methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and ethoxyethyl (meth)acrylate; aromatic group-containing (meth)acrylic acid esters such as aryl (meth)acrylate such as phenyl (meth)acrylate; non-crosslinked (meth)acrylamide and its derivatives; and non-crosslinked (meth)acrylic acid esters having a tertiary amino group such as N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate.

[0080] The acrylic polymer (e11) may consist of only one acrylic monomer that does not have the functional group, or it may consist of two or more monomers. If there are two or more monomers, their combination and ratio can be arbitrarily selected.

[0081] Examples of the non-acrylic monomers include olefins such as ethylene and norbornene; vinyl acetate; and styrene. The non-acrylic monomers constituting the acrylic polymer (e11) may consist of only one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected.

[0082] In the acrylic polymer (e11), the ratio (content) of the amount of constituent units derived from the functional group-containing acrylic monomer to the total amount of constituent units is preferably 0.1 to 50% by mass, more preferably 1 to 40% by mass, and particularly preferably 3 to 30% by mass. Having this ratio within this range allows the content of energy-ray-curable groups in the acrylic resin (e1-1) obtained by copolymerization of the acrylic polymer (e11) and the energy-ray-curable compound (e12) to easily adjust the degree of curing of the protective film within a preferred range.

[0083] The acrylic polymer (e11) constituting the acrylic resin (e1-1) may consist of only one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected.

[0084] In the energy-ray curable resin (E), the content of the acrylic resin (e1-1) is preferably 1 to 40% by mass, more preferably 2 to 30% by mass, and particularly preferably 3 to 20% by mass.

[0085] • Energy ray curable compound (e12) The energy ray curable compound (e12) preferably has one or more groups selected from the group consisting of isocyanate groups, epoxy groups, and carboxyl groups as groups that can react with the functional groups of the acrylic polymer (e11), and more preferably has an isocyanate group as such. For example, if the energy ray curable compound (e12) has an isocyanate group as such, this isocyanate group readily reacts with the hydroxyl group of the acrylic polymer (e11) having a hydroxyl group as such as a functional group.

[0086] The energy ray curable compound (e12) preferably has 1 to 5 energy ray curable groups per molecule, and more preferably 1 to 2.

[0087] Examples of the energy-ray curable compound (e12) include 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, and 1,1-(bisacryloyloxymethyl)ethyl isocyanate; Acryloyl monoisocyanate compounds obtained by the reaction of a diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth)acrylate; Examples include acryloyl monoisocyanate compounds obtained by the reaction of a diisocyanate compound or polyisocyanate compound with a polyol compound and hydroxyethyl (meth)acrylate. Among these, the energy ray curable compound (e12) is preferably 2-methacryloyloxyethyl isocyanate.

[0088] The energy ray curable compound (e12) constituting the acrylic resin (e1-1) may consist of only one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected.

[0089] In the acrylic resin (e1-1), the ratio of the content of energy-ray-curable groups derived from the energy-ray-curable compound (e12) to the content of the functional groups derived from the acrylic polymer (e11) is preferably 20 to 120 mol%, more preferably 35 to 100 mol%, and particularly preferably 50 to 100 mol%. Having the content within this range increases the adhesive strength of the protective film after curing. Note that if the energy-ray-curable compound (e12) is a monofunctional compound (having one of the groups in one molecule), the upper limit of the content ratio is 100 mol%, but if the energy-ray-curable compound (e12) is a polyfunctional compound (having two or more of the groups in one molecule), the upper limit of the content ratio may exceed 100 mol%.

[0090] The weight-average molecular weight (Mw) of the polymer (e1) is preferably 100,000 to 2,000,000, and more preferably 300,000 to 1,500,000. Here, "weight-average molecular weight" is as explained earlier.

[0091] If the polymer (e1) is crosslinked with a crosslinking agent in at least a portion thereof, the polymer (e1) may be a monomer that does not fall under any of the above-described monomers that constitute the acrylic polymer (e11) and has a group that reacts with the crosslinking agent, which is polymerized and crosslinked at the group that reacts with the crosslinking agent, or it may be a group that reacts with the functional group derived from the energy ray curable compound (e12).

[0092] The polymer (e1) contained in the thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected.

[0093] (Compounds with energy-ray curable groups and a molecular weight of 100 to 80,000 (e2)) Examples of energy-ray curable groups in compound (e2) having an energy-ray curable group and a molecular weight of 100 to 80,000 include groups containing energy-ray curable double bonds, and preferred examples include (meth)acryloyl groups and vinyl groups.

[0094] The compound (e2) is not particularly limited as long as it satisfies the above conditions, but examples include low molecular weight compounds having energy ray curable groups, epoxy resins having energy ray curable groups, and phenolic resins having energy ray curable groups.

[0095] Among the compounds (e2) mentioned above, 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, polyalkylene glycol (meth)acrylates such as polyethylene glycol di(meth)acrylate, propoxylated ethoxylated bisphenol E 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, tricyclodecanedimethanol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, and 1,4-butylene glycoside. Difunctional (meth)acrylates such as di(meth)acrylate, 1,6-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, 2-hydroxy-1,3-di(meth)acryloxypropane, and dicyclopentanyl di(meth)acrylate; 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, tetramethylolmethane tetra(meth)acrylate, ethoxylated pentaerythritol tetra( Polyfunctional (meth)acrylates such as meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol poly(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; Oligoester (meth)acrylate; urethane (meth)acrylate oligomer; epoxy-modified (meth)acrylate; polyether (meth)acrylate other than the above polyalkylene glycol (meth)acrylate; Examples include polyfunctional (meth)acrylate oligomers such as urethane (meth)acrylate oligomers; and itaconic acid oligomers.

[0096] Of the aforementioned compounds (e2), epoxy resins having energy-ray curable groups and phenolic resins having energy-ray curable groups also fall under the category of resins constituting thermosetting component (B), but in this invention they are treated as compounds (e2).

[0097] The compound (e2) preferably has a weight-average molecular weight of 100 to 30,000, and more preferably 300 to 10,000.

[0098] The compound (e2) contained in the thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected.

[0099] The energy-curable compounds used in polymerization may be used individually or in combination of two or more. When two or more energy-curable compounds are used in polymerization, their combination and ratio can be arbitrarily selected. For example, the polymer (e1) and the compound (e2) may be used individually or in combination.

[0100] In thermosetting resin films (x1) and thermosetting resin compositions (x1-1), when an energy-ray curable resin (E) is used, the content of the energy-ray curable resin (E) is preferably 1 to 95% by mass, more preferably 5 to 90% by mass, and even more preferably 10 to 85% by mass, based on the total amount of active ingredients in the thermosetting resin composition (x1-1). -Photopolymerization initiator (F)- If the thermosetting resin film (x1) and thermosetting resin composition (x1-1) contain an energy ray curable resin (E), the thermosetting resin film (x1) and thermosetting resin composition (x1-1) may contain a photopolymerization initiator (F) in order to efficiently advance the polymerization reaction of the energy ray curable resin (E).

[0101] Examples of photopolymerization initiators (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.

[0102] The photopolymerization initiator (F) may be used alone or in combination of two or more types. If there are two or more types of photopolymerization initiator (F), their combination and ratio can be arbitrarily selected.

[0103] In the thermosetting resin film (x1) and thermosetting resin composition (x1-1), when a photopolymerization initiator (F) is used, 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, based on 100 parts by mass of the energy ray curable resin (E).

[0104] -Additive (G)- The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain additive (G) as long as the effects of the present invention are not impaired. Additive (G) may be any known additive and can be arbitrarily selected depending on the purpose, and is not particularly limited. Preferred additives (G) include, for example, rheology control agents, coupling agents, crosslinking agents, surfactants, plasticizers, antistatic agents, antioxidants, leveling agents, gettering agents, and silicone oils.

[0105] Additive (G) may be used alone or in combination of two or more types. If there are two or more types of additive (G), their combination and ratio can be arbitrarily selected. The amount of additive (G) is not particularly limited and should be selected as appropriate depending on the purpose.

[0106] -solvent- The thermosetting resin composition (x1-1) preferably further contains a solvent. A thermosetting resin composition (x1-1) containing a solvent has good handling properties. The solvent is not particularly limited, but preferred solvents include, for example, 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 types. If two or more solvents are used, their combination and ratio can be arbitrarily selected. The solvent is preferably methyl ethyl ketone or the like, as it allows for more uniform mixing of the components contained in the thermosetting resin composition (x1-1).

[0107] -Method for preparing a thermosetting resin composition (x1-1)- A thermosetting resin composition (x1-1) is prepared by blending the components that make it up. The order in which each component is added during formulation is not particularly limited, and two or more components may be added simultaneously. When using a solvent, the solvent may be used after pre-diluting the formulation by mixing it with any of the other components, or the solvent may be used by mixing it with the other components without pre-diluting them. The method of mixing each component during formulation is not particularly limited; it can be appropriately selected from known methods such as mixing by rotating a stirring bar or impeller, mixing using a mixer, or mixing by applying ultrasonic waves. The temperature and time during the addition and mixing of each component are not particularly limited as long as the components do not deteriorate, and can be adjusted as appropriate, but a temperature of 15 to 30°C is preferred.

[0108] (Energy-ray curable resin film (x2)) The energy ray-curable resin film (x2) contains an energy ray-curable component (α). The energy ray-curable resin film (x2) is formed from, for example, an energy ray-curable resin composition (x2-1) containing an energy ray-curable component (α). The energy ray curable component (α) is preferably uncured, more preferably tacky, and even more preferably both uncured and tacky. In this specification, the following description of "the content of each component on a total basis of the 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)".

[0109] -Energy ray curing component (α)- The energy ray curable component (α) is a component that hardens upon irradiation with energy rays, and is also a component that imparts film-forming properties and flexibility to the energy ray curable resin film (x2). Examples of the energy-ray curable component (α) include a polymer (α1) having an energy-ray curable group and a weight-average molecular weight of 80,000 to 2,000,000, and a compound (α2) having an energy-ray curable group and a molecular weight of 100 to 80,000. The polymer (α1) may be at least partially crosslinked with a crosslinking agent, or it may not be crosslinked.

[0110] Furthermore, the polymer (α1) and compound (α2) in the energy-ray curable resin composition (x2-1) are the same as the polymer (e1) and compound (e2) in the thermosetting resin composition (x1-1), and their preferred embodiments are also the same as those of the polymer (e1) and compound (e2) in the thermosetting resin composition (x1-1).

[0111] - A polymer (β) that does not have energy-ray curable groups - When the energy-ray curable resin composition (x2-1) and the energy-ray curable resin film (x2) contain compound (α2) as the energy-ray curable component (α), it is preferable that they also contain a polymer (β) that does not have an energy-ray curable group. The polymer (β) that does not have energy-ray curable groups may be crosslinked with a crosslinking agent in at least a portion of it, or it may not be crosslinked.

[0112] Examples of polymers (β) that do not have energy-ray curable groups include acrylic polymers, phenoxy resins, urethane resins, polyesters, rubber resins, acrylic urethane resins, and polyvinyl acetals. Among these, polymers (β) are preferably acrylic polymers (hereinafter sometimes abbreviated as "acrylic polymer (β-1)") and polyvinyl acetals.

[0113] The acrylic polymer (β-1) may be any known polymer, for example, a homopolymer of one acrylic monomer, or a copolymer of two or more acrylic monomers. Alternatively, the acrylic polymer (β-1) may be a copolymer of one or more acrylic monomers and one or more monomers other than acrylic monomers (non-acrylic monomers).

[0114] Examples of the acrylic monomers constituting the acrylic polymer (β-1) include alkyl (meth)acrylates, (meth)acrylates having a cyclic skeleton, glycidyl group-containing (meth)acrylates, hydroxyl group-containing (meth)acrylates, and substituted amino group-containing (meth)acrylates.

[0115] Examples of alkyl (meth)acrylates 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 isono(meth)acrylate. Examples of alkyl esters include (meth)acrylates such as nyl, 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), in which the alkyl group constituting the alkyl ester has a chain structure with 1 to 18 carbon atoms.

[0116] Examples of (meth)acrylic acid esters having a cyclic skeleton include cycloalkyl (meth)acrylate esters such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate; aralkyl (meth)acrylate esters such as benzyl (meth)acrylate; cycloalkenyl (meth)acrylate esters such as dicyclopentenyl (meth)acrylate; and cycloalkenyloxyalkyl (meth)acrylate esters such as dicyclopentenyloxyethyl (meth)acrylate.

[0117] Examples of glycidyl group-containing (meth)acrylic acid esters include glycidyl (meth)acrylate. Examples of hydroxyl group-containing (meth)acrylic acid esters 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)acrylic acid.

[0118] Examples of non-acrylic monomers that constitute the acrylic polymer (β-1) include olefins such as ethylene and norbornene; vinyl acetate; and styrene.

[0119] As for the polyvinyl acetal, as explained in the section on polymer component (A), polyvinyl formal and polyvinyl butyral are preferred, with polyvinyl butyral being more preferred. Furthermore, as for the polyvinyl butyral, those having the constituent units represented by the above formulas (i)-1, (i)-2, and (i)-3 are preferred. The preferred embodiments of polyvinyl butyral are as described in polymer component (A), and the explanation is omitted.

[0120] Examples of polymers (β) that do not have energy-ray curable groups and are crosslinked by a crosslinking agent include polymers (β) in which reactive functional groups react with the crosslinking agent. The reactive functional group can be appropriately selected depending on the type of crosslinking agent, etc., and is not particularly limited. For example, when the crosslinking agent is a polyisocyanate compound, the reactive functional group can be a hydroxyl group, a carboxyl group, or an amino group, and among these, the hydroxyl group, which has high reactivity with the isocyanate group, is preferred. Furthermore, when the crosslinking agent is an epoxy compound, the reactive functional group can be a carboxyl group, an amino group, or an amide group, and among these, the carboxyl group, which has high reactivity with epoxy groups, is preferred. However, in terms of preventing corrosion of semiconductor wafers and semiconductor chip circuits, it is preferable that the reactive functional group is a group other than a carboxyl group.

[0121] Examples of polymers (β) having reactive functional groups but not energy-ray curable groups include those obtained by polymerizing monomers having at least reactive functional groups. In the case of acrylic polymers (β-1), either or both of the acrylic and non-acrylic monomers listed as constituent monomers may have reactive functional groups. For example, an example of a polymer (β) having a hydroxyl group as a reactive functional group is one obtained by polymerizing a hydroxyl group-containing (meth)acrylic acid ester. In addition, polymers obtained by polymerizing monomers in which one or more hydrogen atoms are substituted with the reactive functional group in the aforementioned acrylic or non-acrylic monomers may also be used.

[0122] In a polymer (β) having a reactive functional group, the ratio (content) of the amount of constituent units derived from the monomer having a reactive functional group to the total mass of the constituent units is preferably 1 to 20% by mass, and more preferably 2 to 10% by mass. When the ratio is within this range, the degree of crosslinking in polymer (β) is within a more preferable range.

[0123] The weight-average molecular weight (Mw) of the polymer (β) that does not have energy-ray curable groups is preferably 10,000 to 2,000,000, and more preferably 20,000 to 1,500,000, from the viewpoint that the film-forming properties of the energy-ray curable resin composition (x2-1) will be better.

[0124] The polymer (β) that does not have energy-ray curable groups may be used alone or in combination of two or more types. When there are two or more polymers (β) that do not have energy-ray curable groups, their combination and ratio can be arbitrarily selected.

[0125] Examples of energy-ray curable resin compositions (x2-1) include those containing either or both of the polymer (α1) and the compound (α2). Furthermore, if the energy-ray curable resin composition (x2-1) contains compound (α2), it is preferable that it also contains a polymer (β) that does not have an energy-ray curable group, and in this case, it is also preferable that it contains polymer (α1). Furthermore, the energy-ray curable resin composition (x2-1) may not contain compound (α2) and may contain both polymer (α1) and polymer (β) that does not have an energy-ray curable group.

[0126] When the energy-ray curable resin composition (x2-1) contains a polymer (α1), a compound (α2), and a polymer (β) that does not have an energy-ray curable group, the content of compound (α2) is preferably 10 to 400 parts by mass, and more preferably 30 to 350 parts by mass, based on 100 parts by mass of the total content of polymer (α1) and polymer (β) that does not have an energy-ray curable group.

[0127] The total content of the energy ray-curable component (α) and the polymer (β) without energy ray-curable groups is preferably 5 to 90% by mass, more preferably 10 to 80% by mass, and even more preferably 20 to 70% by mass, based on the total amount of active ingredients in the energy ray-curable resin composition (x2-1). Having the energy ray-curable component content within this range results in better energy ray curability of the energy ray-curable resin film (x2).

[0128] The energy-ray curable resin composition (x2-1) may contain, in addition to the energy-ray curable component, one or more components selected from the group consisting of thermosetting components, photopolymerization initiators, fillers, coupling agents, crosslinking agents, and additives, 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 energy-ray curable resin film (x2) formed has improved adhesion to the adherend upon heating, and the strength of the cured resin film formed from this energy-ray curable resin film (x2) is also improved.

[0129] The thermosetting component, photopolymerization initiator, and additive in the energy ray curable resin composition (x2-1) are the same as those in the thermosetting component (B), photopolymerization initiator (F), filler (D), and additive (G) in the thermosetting resin composition (x1-1), respectively.

[0130] In the energy-ray curable resin composition (x2-1), the thermosetting component, photopolymerization initiator, filler, and additive may each be used individually or in combination of two or more. When two or more are used in combination, the combination and ratio can be arbitrarily selected. The content of thermosetting components, photopolymerization initiators, fillers, and additives in the energy ray curable resin composition (x2-1) can be adjusted as appropriate depending on the purpose, and is not particularly limited.

[0131] The energy-ray curable resin composition (x2-1) is preferable to further contain a solvent, as its handling properties are improved by dilution. Examples of solvents contained in the energy-ray-curable resin composition (x2-1) include the same solvent as that 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 types. When using two or more types in combination, the combination and ratio can be arbitrarily selected.

[0132] -Other ingredients- The energy-ray curable resin composition (x2-1) may contain, in addition to the energy-ray curable component described above, appropriate amounts of components other than the curable component, namely curing accelerators (C), fillers (D), additives (G), etc., similar to the case of the thermosetting resin film (x1) described earlier.

[0133] -Method for preparing an energy-curable resin composition (x2-1)- The energy-ray curable resin composition (x2-1) is obtained by blending the components that constitute it. The order in which the components are added is not particularly limited, and two or more components may be added simultaneously. When using a solvent, the solvent may be used after pre-diluting the mixture by mixing it with any of the other components, or the solvent may be used by mixing it with the other components without pre-diluting them. The method of mixing each component during formulation is not particularly limited, and any known method may be appropriately selected, such as mixing by rotating a stirring bar or impeller; mixing using a mixer; or mixing by applying ultrasound. The temperature and time during the addition and mixing of each component are not particularly limited as long as the components do not deteriorate, and can be adjusted as appropriate, but a temperature of 15 to 30°C is preferred.

[0134] (Preparation of a curable resin film (x)) The curable resin film (x) can be manufactured, for example, by coating the surface to be formed with a curable resin composition such as the thermosetting resin composition (x1-1) or the energy ray curable resin composition (x2-1) of this embodiment (hereinafter also referred to as curable resin composition (x-1)), and drying it as necessary. The curable resin composition (x-1) can be applied by known methods, such as using various coaters including an air knife coater, blade coater, bar coater, gravure coater, roll coater, roll knife coater, curtain coater, die coater, knife coater, screen coater, Meyer bar coater, and kiss coater. The drying conditions after applying the curable resin composition (x-1) are not particularly limited, but for example, the drying temperature can be set to 70 to 130°C and the drying time to 10 seconds to 5 minutes.

[0135] <Structure of a composite sheet> The composite sheet for forming a protective film in this embodiment (hereinafter also simply referred to as the "composite sheet") is a sheet in which a protective film and a support sheet are laminated together. The protective film is a curable resin film (x) having a storage modulus G' of 3.5 MPa or less at 30°C before curing. The following describes the configuration of the composite sheet of this embodiment, specifically the first to third embodiments. However, the configuration of the composite sheet of this embodiment is not limited to the first to third embodiments. For example, the first to third embodiments may have other layers, as long as they do not significantly impair the effects of the present invention. Examples of other layers include adhesive layers.

[0136] (First aspect) Figure 1 shows a first embodiment of the composite sheet of this embodiment. The composite sheet 1a shown in Figure 1 comprises a base material 10 and a curable resin film (x) as a protective film-forming film. In the first embodiment, the support sheet is the base material 10. Although not shown, a release film or the like may be provided on the side of the curable resin film (x) opposite to the base material 10.

[0137] (Second aspect) A second embodiment of the composite sheet of this embodiment is shown in Figure 2. The composite sheet 1b shown in Figure 2 comprises a base material 10, a buffer layer 11, and a curable resin film (x) as a protective film-forming film, in that order. In the second embodiment, the support sheet is a laminate of the base material 10 and the buffer layer 11. Although not shown, a release film or the like may be provided on the side of the curable resin film (x) opposite to the buffer layer 11.

[0138] (Third aspect) A third embodiment of the composite sheet of this embodiment is shown in Figure 3. The composite sheet 1c of the third embodiment has a base material 10, a buffer layer 11, an intermediate release layer 12, and a curable resin film (x) as a protective film-forming film, in this order. That is, as shown in Figure 3, the composite sheet 1c of the third embodiment has a base material 10, a buffer layer 11 laminated on one surface 10a of the base material 10, an intermediate release layer 12 laminated on the side of the buffer layer 11 opposite to the base material 10, and a curable resin film (x) laminated on the side of the intermediate release layer 12 opposite to the buffer layer 13. In the third embodiment, the support sheet is a laminate of the base material 10, the buffer layer 11, and the intermediate release layer 12. Although not shown, a release film or the like may be provided on the side of the curable resin film (x) opposite to the intermediate release layer 12.

[0139] (buffer layer) As described above, the composite sheet of this embodiment may have a buffer layer between the substrate and the curable resin film (x). The buffer layer is a layer that has a buffering effect against forces applied to the buffer layer and layers directly or indirectly adjacent to it. Here, "layers directly or indirectly adjacent to the buffer layer" mainly refers to the curable resin film (x) of this embodiment.

[0140] The buffer layer may consist of only one layer or two or more layers. If the buffer layer consists of multiple layers, these layers may be identical or different from each other, and there are no particular limitations on the combination of these layers.

[0141] The thickness of the buffer layer can be adjusted as appropriate according to the height of the protruding electrodes on the surface of the member, but from the viewpoint of making it easier to exert the effects of the present invention even with relatively tall protruding electrodes, it is preferably 150 to 1,000 μm, more preferably 180 to 800 μm, and even more preferably 200 to 600 μm.

[0142] -Storage modulus (G') of the buffer layer at 80°C- In the composite sheet of this embodiment, the storage modulus (G') of the buffer layer at 80°C is preferably 0.08 MPa or higher. If the storage modulus (G') of the buffer layer at 80°C is 0.08 MPa or higher, it becomes easier to ensure the penetration of the protruding electrode into the curable resin film (x), and thus easier to ensure the reliability of the connection between the chip with the protruding electrode and the substrate. Here, from the viewpoint of making it easier to ensure the penetration of the protruding electrode of the curable resin film (x), the storage modulus (G') of the buffer layer at 80°C is more preferably 0.10 MPa or higher, even more preferably 0.12 MPa or higher, even more preferably 0.14 MPa or higher, and still more preferably 0.16 MPa or higher. Furthermore, 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, thereby making it easier to ensure the embedding ability of the protruding electrodes of the curable resin film (x).

[0143] -Loss tangent (tanδ) of the buffer layer at 80°C- In the composite sheet of this embodiment, the loss tangent (tanδ) of the buffer layer at 80°C is preferably 1.02 or greater. If the loss tangent (tanδ) of the buffer layer at 80°C is 1.02 or higher, it is easier to ensure the embedding ability of the curable resin film (x) into the area around the base of the protruding electrode (penetration of the curable resin film (x) into the area around the base of the protruding electrode). Here, from the viewpoint of making it easier to ensure the embedding ability of the protruding electrodes in the curable resin film (x), the loss tangent (tanδ) of the buffer layer at 80°C is more preferably 1.05 or higher, even more preferably 1.08 or higher, even more preferably 1.12 or higher, and still most preferably 1.16 or higher. Furthermore, 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 higher, thereby making it easier to ensure the penetration of the protruding electrode of the curable resin film (x).

[0144] The storage modulus (G') and loss tangent (tanδ) of the buffer layer at 80°C can be measured, for example, by the following method. The sample size to be measured is 8 mm in diameter and 1 mm thick (5 layers of 200 μm buffer layers stacked together). Using a rheometer (Anton Paar MCR302), the sample, with the release film removed, is sandwiched between parallel plates from above and below. Shear stress is 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, and the shear storage modulus G' and loss tangent tanδ at 80 °C are calculated.

[0145] In this embodiment, the storage modulus (G') and loss tangent (tanδ) of the buffer layer at 80°C can be appropriately adjusted by adjusting the composition of the buffer layer, etc. The details of the buffer layer will be explained below, taking into account the method for adjusting the storage modulus (G') and loss tangent (tanδ) of the buffer layer at 80°C.

[0146] -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 energy ray irradiation. By using urethane (meth)acrylate, flexibility can be provided to the buffer layer, and the storage modulus (G') and loss tangent (tanδ) of the buffer layer at 80°C can be easily adjusted to the above range. The urethane (meth)acrylate may be monofunctional or polyfunctional. In this embodiment, polyfunctional urethane (meth)acrylate is preferred, and bifunctional urethane (meth)acrylate is preferred from the viewpoint of easily adjusting the storage modulus (G') and loss tangent (tanδ) of the buffer layer at 80°C to the above range. The urethane (meth)acrylate may be an oligomer, a polymer, or a mixture thereof. In this embodiment, a urethane (meth)acrylate oligomer is preferred. Urethane (meth)acrylate can be obtained, for example, by reacting a terminal isocyanate urethane prepolymer, which is obtained by reacting a polyol compound with a polyvalent isocyanate compound, with a (meth)acrylate having a hydroxyl group. Note that one or more types of urethane (meth)acrylate may be used. From the viewpoint of easily adjusting the storage modulus (G') and loss tangent (tanδ) of the buffer layer at 80°C to the above range, the content of 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. Furthermore, the content of urethane (meth)acrylate in the buffer 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.

[0147] -Polymerizable monomer- The polymerizable monomer is preferably a polymerizable compound other than the urethane (meth)acrylate mentioned above, and is a compound that can be polymerized with other components by irradiation with energy rays. Specifically, the polymerizable monomer is preferably a compound having at least one (meth)acryloyl group. Examples of polymerizable monomers include (meth)acrylates having alkyl groups with 1 to 30 carbon atoms; (meth)acrylates having functional groups such as hydroxyl groups, amide groups, amino groups, and epoxy groups; (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 alkyl groups with 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 functional group-containing (meth)acrylates 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. Examples include amide group-containing compounds such as lylamide, 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 allylglycidyl 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 (meth)acrylates having an aromatic structure include phenylhydroxypropyl (meth)acrylate, benzyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate. Examples of (meth)acrylates having a heterocyclic structure include tetrahydrofurfuryl(meth)acrylate and morpholine(meth)acrylate. In this embodiment, the polymerizable monomer preferably includes (meth)acrylates having an alkyl group with 1 to 30 carbon atoms and (meth)acrylates having an alicyclic structure. From the viewpoint of easily adjusting the storage modulus (G') and loss tangent (tanδ) of the buffer layer at 80°C to the above range, (meth)acrylates having an alkyl group with 4 to 14 carbon atoms are preferred, and as (meth)acrylates having an alicyclic structure, isobornyl (meth)acrylate and trimethylcyclohexyl (meth)acrylate are preferred. Furthermore, if a buffer layer-forming composition contains a crosslinking agent, (meth)acrylates having functional groups that can react with the crosslinking agent are undesirable. 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 hydroxyl groups is undesirable. The content of polymerizable monomers 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') and loss tangent (tanδ) of the buffer layer at 80°C to the above range. Furthermore, the content of polymerizable monomers 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 urethane (meth)acrylate to polymerizable monomer (urethane (meth)acrylate / polymerizable monomer) in a total of 100 parts by mass of urethane (meth)acrylate and 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') and loss tangent (tanδ) of the buffer layer at 80°C to the above range.

[0148] -Photopolymerization initiator- When the buffer layer forming composition contains the above-mentioned urethane (meth)acrylate and polymerizable monomer, it is preferable that the buffer layer forming composition also contains a photopolymerization initiator. By including a photopolymerization initiator, polymerization proceeds reliably, and the storage modulus (G') and loss tangent (tanδ) of the buffer layer at 80°C can be easily adjusted to the above range. 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. Specifically, examples include 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and 2,2-dimethoxy-1,2-diphenylethane-1-one. These photopolymerization initiators may be used individually or in combination of two or more. The amount of photopolymerization initiator added is preferably 0.05 parts by mass or more and 15 parts by mass or less, and more preferably 0.5 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the total of urethane (meth)acrylate and polymerizable monomer.

[0149] -Chain Transfer Agent- The buffer layer forming composition preferably contains a chain transfer agent. The chain transfer agent can induce a chain transfer reaction and regulate the progress of the curing reaction of the buffer layer forming composition. By including a chain transfer agent, components with relatively short molecular chains can remain even after curing, so that the cured polymer has a relatively flexible structure. As a result, the storage modulus (G') and loss tangent (tanδ) of the buffer layer at 80°C can be easily adjusted to the above range. Examples of chain transfer agents include thiol group-containing compounds. Examples of thiol group-containing compounds include nonyl mercaptan, 1-dodecanethiol, 1,2-ethanedithiol, 1,3-propanedithiol, triazinethiol, triazinedithiol, triazinetrithiol, 1,2,3-propanetrithiol, tetraethylene glycol-bis(3-mercaptopropionate), trimethylolpropanetris(3-mercaptopropionate), pentaerythritoltetrakis(3-mercaptopropionate), and pentaerythritol. Examples include thritol tetrakisthioglucolate, 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. The chain transfer agent may be used individually or in combination of two or more types. From the viewpoint of easily adjusting the storage modulus (G') and loss tangent (tanδ) of the buffer layer at 80°C to the above range, the amount of chain transfer agent is preferably 1.0 to 2.5 parts by mass, more preferably 1.2 to 2.0 parts by mass, and even more preferably 1.3 to 1.8 parts by mass, per 100 parts by mass of the total of urethane (meth)acrylate and polymerizable monomer.

[0150] -Other ingredients- The buffer layer may contain other components. These other components are not particularly limited and can be appropriately selected depending on the purpose.

[0151] -Preparation of a buffer layer- As a composition for forming a buffer layer, 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, can be prepared. Examples of solvents include organic solvents such as methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, and isopropanol. Then, a buffer layer-forming composition or the like is applied to a release film or 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 this coating film is cured to form a buffer layer on the substrate. In this embodiment, it is preferable to cure the coating film 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. By doing so, the degree of curing of the buffer layer can be controlled, and the storage modulus (G') and loss tangent (tanδ) of the buffer layer at 80°C can be easily adjusted to the above range. If the energy source is ultraviolet light, the ultraviolet irradiation conditions are preferably such that the ultraviolet irradiance is 30-500 mW / cm². 2 More preferably 50-340 mW / cm² 2 The ultraviolet radiation dose (cumulative light dose) is preferably 100 to 2,500 mJ / cm². 2 More preferably 150 to 2,000 mJ / cm² 2 That is the case. When irradiating with ultraviolet light multiple times, it is preferable that the illuminance and irradiation dose are greater than those of the previous irradiation. Alternatively, the coated film may be exposed to oxygen and irradiated with energy rays, and then the coated film may be shielded from oxygen and irradiated with energy rays again.

[0152] (Intermediate delamination layer) As described above, the composite sheet of this embodiment may have an intermediate release layer between the buffer layer and the curable resin film (x). The intermediate release layer is provided to easily peel off the buffer layer from the curable resin film (x) after the curable resin film (x) has been attached to the protruding electrode forming surface of the member with protruding electrodes by attaching the composite sheet to the protruding electrode forming surface.

[0153] The intermediate delamination layer is in the form of a sheet or film, and its constituent material is not particularly limited. The intermediate delamination layer preferably contains ethylene-vinyl acetate copolymer (EVA). The intermediate peeling layer may contain other components besides those mentioned above. These other components are not particularly limited and can be appropriately selected depending on the purpose.

[0154] The interdebris layer may be a single layer or a multi-layer structure of two or more layers. If the interdebris layer consists of multiple layers, these layers may be identical or different from each other, and there are no particular limitations on the combination of these layers.

[0155] The thickness of the interlayer is not particularly limited, but is preferably 5 to 30 μm, more preferably 6 to 25 μm, and even more preferably 7 to 20 μm.

[0156] (base material) The base material is in the form of a sheet or film, and its constituent materials include, for example, the following various resins. Examples of resins constituting the base material include polyethylene 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 such as ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, and ethylene-norbornene copolymer (polymers obtained using ethylene as a monomer); and vinyl chloride-based resins such as polyvinyl chloride and vinyl chloride copolymer (using vinyl chloride as a monomer). Examples of resins obtained from this process include: polystyrene; polycycloolefin; polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene isophthalate, polyethylene-2,6-naphthalenedicarboxylate, and all aromatic polyesters having aromatic cyclic groups as all constituent units; copolymers of two or more of the above polyesters; poly(meth)acrylic acid esters; polyurethane; polyurethane acrylate; polyimide; polyamide; polycarbonate; fluororesin; polyacetal; modified polyphenylene oxide; polyphenylene sulfide; polysulfone; polyether ketone; and the like. Furthermore, examples of resins constituting the base material include polymer alloys such as mixtures of the above-mentioned polyester and other resins. It is preferable that the polymer alloy of polyester and other resins contains a relatively small amount of the resin other than polyester. Furthermore, examples of resins constituting the base material include crosslinked resins obtained by crosslinking one or more of the above-mentioned resins; and modified resins such as ionomers using one or more of the above-mentioned resins. The resins that make up the base material may be used individually or in combination of two or more types.

[0157] The base material may consist of only one layer or two or more layers. If the base material consists of multiple layers, these layers may be identical or different from each other, and there are no particular limitations on the combination of these layers.

[0158] 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.

[0159] The base material is preferably one with high thickness accuracy, that is, one in which thickness variation is suppressed regardless of the location. Among the constituent materials mentioned above, examples of materials with high thickness accuracy that can be used to construct such a base material include polyethylene, polyolefins other than polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyesters other than polyethylene terephthalate and polybutylene terephthalate, and ethylene-vinyl acetate copolymers.

[0160] In addition to the main constituent materials such as the resin mentioned above, the base material may also contain various known additives such as fillers, colorants, antioxidants, organic lubricants, catalysts, and plasticizers.

[0161] The substrate may be transparent or opaque, may be colored depending on the purpose, or may have other layers deposited on it.

[0162] The substrate can be manufactured by known methods. For example, a substrate containing a resin can be manufactured by molding a resin composition containing the above-mentioned resin.

[0163] (Method of manufacturing composite sheets) The composite sheet of this embodiment can be manufactured by sequentially stacking the above-mentioned layers in corresponding positional relationships. For example, a composite sheet having a laminated structure of a substrate and a curable resin film (x) can be manufactured by the method shown below. The curable resin composition (x-1) of this embodiment is applied to the release surface of the release film, and a curable resin film (x) is formed on the release film by drying as necessary. Next, the substrate and the exposed surface of the curable resin film (x) opposite to the release film are bonded together. This yields a composite sheet having a laminated structure of the substrate and the curable resin film (x). The laminate of the substrate and the curable resin film exhibits good adhesion to formation surfaces with a protruding electrode height of 150 μm or less, and even better adhesion to formation surfaces with a protruding electrode height of 80 μm or less. The release film provided on the curable resin film (x) in the composite sheet can be removed at any stage between the time of manufacture of the composite sheet and the time of use. Furthermore, a composite sheet having a laminated structure of a substrate and a curable resin film (x) can also be manufactured by coating one side of the substrate with a curable resin composition (x-1) and drying it as necessary.

[0164] Furthermore, for example, a composite sheet having a base material, a buffer layer, and a curable resin film (x) in this order can be manufactured by the method shown below. A buffer layer-forming composition is applied to the release surface of the release film and dried to form a buffer layer on the release film. Then, the side of the buffer layer that is not in contact with the release film is bonded to the substrate to obtain a laminate (first laminated sheet) in which the substrate, buffer layer, and release film are stacked in this order. Separately, the curable resin composition (x-1) of this embodiment is applied to the release surface of the release film and dried as necessary to form a curable resin film (x) on the release film. Next, after removing the release film from the first laminated sheet, the exposed surface of the buffer layer opposite to the substrate and the exposed surface of the curable resin film (x) opposite to the release film are bonded together. This yields a composite sheet for forming a protective film having a laminated structure of a substrate, a buffer layer, and a curable resin film (x). The release film provided on the curable resin film (x) in the composite sheet can be removed at any stage between the time of manufacture of the composite sheet and the time of use.

[0165] A composite sheet including layers other than the above-mentioned respective layers can be produced by appropriately adding or omitting steps in the above-mentioned production method so that the lamination position of each layer becomes a desired position.

[0166] [Applications of Protective Film-Forming Film] The protective film-forming film of the present embodiment can of course be used when being attached to the protruding electrode-forming surface of a member with protruding electrodes using a roller attaching apparatus such as a laminating roller, and by opposing the protective film-forming film to the protruding electrode-forming surface of the member with protruding electrodes and simultaneously pressing the entire surface of the member with protruding electrodes into the protective film-forming film, generation of air bubbles can be suppressed even when the protective film-forming film is attached to the protruding electrode-forming surface. Therefore, it can be suitably used also in the latter application (entire surface pressing).

[0167] [Method for Producing Semiconductor Device] The method for producing a semiconductor device of the present embodiment is a method for producing a semiconductor device, in which a protective film is formed on the protruding electrode-forming surface of a member with protruding electrodes using a protective film-forming film, the method comprising: a step (S1) of opposing the protective film-forming film to the protruding electrode-forming surface of the member with protruding electrodes, and simultaneously pressing the entire surface of the member with protruding electrodes into the protective film-forming film, to attach the protective film-forming film to the protruding electrode-forming surface; a step (S2) of curing the protective film-forming film; The protective film-forming film of the present embodiment can be particularly suitably used in the above-described method for producing a semiconductor device. The member with protruding electrodes is not limited, but is preferably a semiconductor chip with protruding electrodes. Examples of the semiconductor chip include semiconductor chips on which circuits such as wirings, capacitors, diodes, and transistors are formed on the surface. The material of the chip is not particularly limited, and examples thereof include silicon, silicon carbide, compound semiconductors, glass, and sapphire. The chip size is not particularly limited, and for example, 4 mm 2~100mm 2 That is the case. The chip thickness is not particularly limited, but for example, it is between 50 μm and 1,000 μm. The method for manufacturing the semiconductor device of this embodiment will be described below with reference to the drawings. In Figure 4, for the sake of simplification, an example is given in which a single chip with a protruding electrode is used, but multiple protective film-forming films may be attached to the chip with the protruding electrode simultaneously.

[0168] <Process (S1): Pasting Process> Figure 4 is a schematic cross-sectional view illustrating the application process. In the bonding process, the entire surface of the semiconductor chip 80 with protruding electrodes is simultaneously pressed onto the curable resin film (x) used as a protective film, thereby bonding the curable resin film (x) to the protruding electrode forming surface 20a. The method for simultaneously pressing the entire surface of the semiconductor chip 80 with protruding electrodes into the curable resin film (x) is not particularly limited, but one example is the method using the pressurizing device 30 shown in Figure 4. The pressurizing device 30 shown in Figure 4 is broadly composed of an adsorption stage 31 and a head 32. The object to be pressed is pressed by pressing the head 32 against the object placed on the adsorption stage 31, thereby pressurizing the object. In this embodiment, a curable resin film (x) as a protective film is placed on the adsorption stage 31, and a semiconductor chip 80 with protruding electrodes is placed on the curable resin film (x) with the protruding electrode forming surface 20a facing downwards. Then, by pressing the entire back surface of the semiconductor chip 80 with protruding electrodes with the head 32, the entire surface of the semiconductor chip 80 with protruding electrodes is simultaneously pressed against the curable resin film (x), thereby attaching the curable resin film (x) to the protruding electrode forming surface 20a. Here, it is preferable that the pressurizing device 30 is provided with a temperature control device (not shown). The temperature control device is provided on either the adsorption stage 31 or the head 32, or both, but from the viewpoint of controlling the application temperature, it is preferable that the temperature control device is provided on the adsorption stage 31. Furthermore, from the viewpoint of evenly pressing the entire surface of the semiconductor chip 80 with protruding electrodes, it is preferable to provide a material (for example, aluminum foil, etc.) larger than the area of ​​the back surface of the semiconductor chip 80 with protruding electrodes between the head 32 and the back surface of the semiconductor chip 80 with protruding electrodes. Alternatively, the contact surface of the head 32 with the back surface of the semiconductor chip 80 with protruding electrodes may be made of a material larger than the area of ​​the back surface of the semiconductor chip 80 with protruding electrodes. In addition, by providing a material (for example, aluminum foil, etc.) larger than the area of ​​the back surface of the semiconductor chip 80 with protruding electrodes, contamination of the head 32 when the protective film-forming film seeps out from the chip edge can also be prevented. Furthermore, it is preferable that the curable resin film (x) is a composite sheet (α) placed on the support sheet (y). By using a composite sheet (α), the back surface of the support sheet (y) (the surface not in contact with the curable resin film (x)) can be used as the adsorption surface of the adsorption stage 31 to securely fix the composite sheet (α), while the protruding electrode forming surface 20a of the semiconductor chip 80 with protruding electrodes can be well pressed into the curable resin film (x), making it easier to achieve good embedding of the protruding electrodes 21 by the curable resin film (x).

[0169] The heating temperature used when simultaneously pressing the entire back surface of the semiconductor chip with protruding electrodes into the curable resin film (x) for forming a protective film is not particularly limited and may be, for example, 23°C to 100°C, but preferably 30°C to 90°C. The pressure applied when simultaneously pressing the entire back surface of the semiconductor chip with protruding electrodes into the curable resin film (x) used as a protective film is not particularly limited and may be, for example, 2 MPa to 20 MPa, but is preferably 4 MPa to 10 MPa.

[0170] The height of the protruding electrode is not particularly limited, but is preferably 100 μm to 400 μm, more preferably 150 μm to 300 μm, and even more preferably 200 μm to 280 μm. In this specification, "height of the protruding electrode" means the height of the portion of the protruding electrode that is located at the highest position from the surface on which the protruding electrode is formed. The width of the protruding electrode is not particularly limited, but is preferably 100 μm to 350 μm, more preferably 150 μm to 300 μm, and even more preferably 200 to 280 μm. In this specification, "width of the protruding electrode" means the maximum length of a line segment obtained by drawing a straight line between two different points on the surface of the protruding electrode when the protruding electrode is viewed from above in a plan view from a direction perpendicular to the surface on which the protruding electrode is formed. The distance between adjacent protruding electrodes is not particularly limited, but is preferably 80 μm to 250 μm, more preferably 100 μm to 200 μm, and even more preferably 130 μm to 160 μm. In this specification, "distance between adjacent protruding electrodes" means the minimum distance between the surfaces of adjacent protruding electrodes. Herein, the semiconductor device manufacturing method of this embodiment is particularly effective in suppressing the generation of bubbles when attaching a cured resin film (x) as a protective film to a semiconductor chip having a region on the protruding electrode formation surface where protruding electrodes are absent (protruding electrode-free region). When a protruding electrode-free region exists, bubbles tend to form in that area during attachment. However, the protective film-forming film of this embodiment is a curable resin film (x) whose storage modulus G' at 30°C before curing is 3.5 MPa or less, and it can suppress the generation of bubbles even in such a region. For example, the area of ​​the region where the protruding electrode is absent is 3 mm². 2 ~7mm 2 That is the case. The protruding electrode is preferably a bump.

[0171] <Process (S2): Curing process> After attaching a protective film to the surface of a semiconductor chip with protruding electrodes, the protective film is cured to form a protective film on the surface of the semiconductor chip with protruding electrodes. This results in a semiconductor chip with a protective film on the surface of the protruding electrodes. The conditions for curing the protective film are not particularly limited and can be appropriately adjusted and determined depending on the type of material constituting the protective film.

[0172] <Other processes: Exposure process, cutting process, mounting process> After performing step (S2), a step may be performed to remove the protective film covering the top of the protruding electrode, or the protective film attached to a part of the top of the protruding electrode, in order to expose the top of the protruding electrode. Exposure treatments that expose the top of a protruding electrode include etching treatments such as wet etching and dry etching. Examples of dry etching processes include plasma etching. Furthermore, if the top of the protruding electrode is not exposed on the surface of the protective film, the exposure process may be performed to retract the protective film until the top of the protruding electrode is exposed.

[0173] In the cutting process, the protective film is cut along the chip shape. The cutting process is carried out as appropriate by known methods such as dicing. The cutting process may be carried out after process (S1) and before process (S2). In the mounting process, the semiconductor chip with the protective film obtained in the curing process is flip-chip connected to the substrate at the top of the protruding electrode (not shown). At this time, the semiconductor chip with the protective film is connected to the circuit formation surface of the substrate.

[0174] Subsequently, using the circuit board with the semiconductor chip already mounted, obtained in this manner, a semiconductor package can be fabricated according to a known method, and the desired semiconductor device can be manufactured using this semiconductor package. [Examples]

[0175] The present invention will be specifically described by the following examples, but the present invention is not limited to these examples. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or other reasons, measurements can be taken using other instruments with equivalent performance.

[0176] [Method for measuring weight-average molecular weight (Mw)] The method for measuring the weight-average molecular weight (Mw) in this embodiment is described below. Measurements were taken using a gel permeation chromatograph (manufactured by Tosoh Corporation, product name "HLC-8320GPC") under the following conditions, and the values ​​measured in terms of standard polystyrene equivalent were used. (Measurement conditions) • Column: A series of "TSKgel guardcolumn SuperHzH", "TSKgel SuperHZM-M", "TSKgel SuperHZM-M", and "TSKgel SuperHZ2000" (all manufactured by Tosoh Corporation) linked together in sequence. Column temperature: 40°C • Developing solvent: tetrahydrofuran • Standard material: Polystyrene • Injection volume: 20 μL • Flow rate: 0.35 mL / min • Detector: Differential refractometer

[0177] [Manufacturing of thermosetting resin films] A thermosetting resin film was manufactured using the method described below.

[0178] <Raw materials for thermosetting resin films> The raw materials used in the manufacture of the thermosetting resin film are listed below.

[0179] "Polymer component (A)" (A)-1: Polyvinyl butyral having constituent units represented by the following formulas (i)-1, (i)-2, and (i)-3 (Sekisui Chemical Co., Ltd.'s "Eslec BL-10", weight-average molecular weight 25,000, glass transition temperature 59°C). [ka] (In the formula, l is approximately 28, m is between 1 and 3, and n is an integer between 68 and 74.) (A)-2: Polyarylate (manufactured by Unitika Corporation, product name "Unifiner M-2040")

[0180] "Epoxy resin (B1)" • (B1)-1: Liquid modified bisphenol A type epoxy resin (DIC Corporation's "Epiclon EXA-4850-150", number average molecular weight 900, epoxy equivalent 450 g / eq, liquid epoxy resin) • (B1)-2: Liquid special epoxy resin (ADEKA Corporation's "ADEKA Resin EP-4005", epoxy equivalent 510g / eq) • (B1)-3: Dicyclopentadiene type epoxy resin (DIC Corporation's "Epiclon HP-7200HH", epoxy equivalent 254-264 g / eq, solid epoxy resin) • (B1)-4: Naphthalene-type epoxy resin (DIC Corporation's "Epiclon HP-5000", epoxy equivalent 252 g / eq, solid epoxy resin) • (B1)-5: Naphthalene-type epoxy resin (DIC Corporation's "Epiclon HP-4710", epoxy equivalent 170g / eq, solid epoxy resin) (B1)-2 is a flexible epoxy resin, and in the above general formula (2), B is a divalent group obtained by removing a hydrogen atom from the hydroxyl group of bisphenol A, and L 1 and L 2 Each of these is a flexible epoxy resin in which polyoxypropylene groups are independently present.

[0181] "Thermosetting agent (B2)" (B2)-1: o-cresol type novolac resin (DIC Corporation's "Phenolite KA-1160")

[0182] "Curing accelerator (C)" (C)-1:2-phenyl-4,5-dihydroxymethylimidazole (Shikoku Chemicals Co., Ltd. "Curesol 2PHZ-PW")

[0183] "Filling material (D)" (D)-1: Spherical silica modified with epoxy groups (Admanano YA050C-MKK, manufactured by Admatex, with an average particle size of 50 nm)

[0184] "Additives (G)" • (G)-1: Surfactant (acrylic polymer, manufactured by BYK, product name "BYK-361N") • (G)-2: Silicone oil (aralkyl-modified silicone oil, manufactured by Momentive Performance Materials Japan, product name "XF42-334")

[0185] [Example 1] A polymer component (A), epoxy resin (B1), thermosetting agent (B2), curing accelerator (C), filler (D), and additive (G) were dissolved or dispersed in methyl ethyl ketone according to the formulations shown in Table 1, and stirred at 23°C to obtain a thermosetting resin composition (x1-1)-1 in which the total concentration of all components other than the solvent was 60% by mass. Note that all amounts of components other than the solvent shown here are the amounts of the target product excluding the solvent. Next, the thermosetting resin composition (x1-1)-1 obtained above was applied to the release surface of a double-release film (Lintec Corporation's "SP-PET502150"), in which one side of a polyethylene terephthalate film had been peeled by silicone treatment, and dried at 120°C for 2 minutes to produce a thermosetting resin film (x1)-1 with a thickness of 45 μm on the double-release film. Next, a thermosetting resin film (x1)-1 with double-sided release films was obtained by laminating a polyethylene terephthalate film (Lintec Corporation, product name "SP-PET381130*", thickness 38 μm), in which one side of the film was peeled off by silicone treatment, onto the exposed surface of the thermosetting resin film (x1)-1.

[0186] [Example 2] The formulation of thermosetting resin composition (x1-1)-1 was changed as shown in Example 2 of Table 1 to prepare thermosetting resin film (x1)-2, and thermosetting resin film (x1)-2 with release films on both sides was obtained.

[0187] [Example 3] The formulation of thermosetting resin composition (x1-1)-1 was modified as shown in Example 3 of Table 1 to produce thermosetting resin film (x1)-3, and the thermosetting resin film (x1)-3 with double-sided release films was obtained.

[0188] [Example 4] The formulation of thermosetting resin composition (x1-1)-1 was modified as shown in Example 4 of Table 1 to produce thermosetting resin film (x1)-4, and the thermosetting resin film (x1)-4 with double-sided release films was obtained.

[0189] [Example 5] The formulation of thermosetting resin composition (x1-1)-1 was modified as shown in Example 5 of Table 1 to produce thermosetting resin film (x1)-5, and the thermosetting resin film (x1)-5 with double-sided release films was obtained.

[0190] [Comparative Example 1] The formulation of thermosetting resin composition (x1-1)-1 was modified as shown in Comparative Example 1 of Table 1 to produce thermosetting resin film (x1')-1, and the thermosetting resin film (x1')-1 with double-sided release films was obtained.

[0191] [Comparative Example 2] The formulation of thermosetting resin composition (x1-1)-1 was modified as shown in Comparative Example 2 of Table 1 to produce thermosetting resin film (x1')-2, and the thermosetting resin film (x1')-2 with double-sided release films was obtained.

[0192] [Comparative Example 3] The formulation of thermosetting resin composition (x1-1)-1 was modified as shown in Comparative Example 3 of Table 1 to produce thermosetting resin film (x1')-3, and the thermosetting resin film (x1')-3 with double-sided release films was obtained.

[0193] [Comparative Example 4] The formulation of thermosetting resin composition (x1-1)-1 was modified as shown in Comparative Example 4 of Table 1 to produce thermosetting resin film (x1')-4, and the thermosetting resin film (x1')-4 with double-sided release films was obtained.

[0194] [evaluation] In this embodiment, the following evaluations 1 to 5 were performed.

[0195] <Evaluation 1: Evaluation of the storage modulus of thermosetting resin film at 30°C before curing> Twenty sheets each of the thermosetting resin films (x1)-1 to (x1)-5 and thermosetting resin films (x1')-1 to (x1')-4 prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were prepared. Next, 22 thermosetting resin films were laminated together and then cut into a 25mm diameter disc (25mmφ) to produce a test specimen of thermosetting resin film with a thickness of 990μm. The lamination conditions for stacking 20 thermosetting resin films are shown below. (Lamination conditions) • Equipment: Desktop laminator (Product name: "LPD3212", manufactured by Fujipla Co., Ltd.) • Adhesion pressure: 0.3 MPa • Application temperature: 60℃ • Application speed: 1 mm / second

[0196] Then, the storage modulus at 30°C was measured for the uncured test specimens. The storage modulus at 30°C was measured by the following method. A viscoelasticity measuring device (Anton Paar's "MCR301") was used, and the installation location for the viscoelasticity measuring device was preheated to 70°C. Then, the test specimen was placed on this installation location, and the test specimen was fixed in place by pressing a measuring jig against the top surface of the specimen. Next, under conditions of a strain of 0.1% and a measurement frequency of 1 Hz, the temperature of the test specimen was increased at a heating rate of 5°C / min in the temperature range of 0°C to 150°C, and the storage modulus G' of the test specimen was measured, obtaining the measured value at 30°C.

[0197] <Evaluation 2: Evaluation of the fracture energy of thermosetting resin film before curing> Five sheets each of the thermosetting resin films (x1)-1 to (x1)-5 and thermosetting resin films (x1')-1 to (x1')-4 prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were prepared. Next, five thermosetting resin films were laminated together and then cut into rectangular shapes measuring 5 mm in width and 100 mm in length to prepare test specimens. The lamination conditions for stacking five thermosetting resin films are shown below. (Lamination conditions) • Equipment: Desktop laminator (Product name: "LPD3212", manufactured by Fujipla Co., Ltd.) • Adhesion pressure: 0.3 MPa • Application temperature: 60℃ • Application speed: 1 mm / second Then, the uncured test specimens were placed in a Tensilon with a constant temperature chamber (Tensilon Universal Material Tester (RTG-1210, manufactured by Orientec Co., Ltd.), constant temperature chamber for the tester (TKC-R3T-GS, manufactured by Orientec Co., Ltd.)) with a chuck length of 50 mm, and the fracture energy was measured under conditions of a temperature of 23°C and a speed of 200 mm / min.

[0198] <Evaluation 3: Evaluation of adhesion by pressing down on the entire surface simultaneously> Five layers each of the thermosetting resin films (x1)-1 to (x1)-5 and thermosetting resin films (x1')-1 to (x1')-4 prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were used to prepare a laminated film with a thickness of 225 μm. The lamination conditions for stacking five thermosetting resin films are shown below. (Lamination conditions) • Equipment: Desktop laminator (Product name: "LPD3212", manufactured by Fujipla Co., Ltd.) • Adhesion pressure: 0.3 MPa • Application temperature: 60℃ • Application speed: 1 mm / second Next, this laminated film was attached to glass to prepare a test sample. The lamination conditions for attaching the laminated film to glass are shown below. (Lamination conditions) ·Apparatus: Tabletop laminator (Product name: "LPD3212", manufactured by FUJIPLA Inc.) ·Lamination pressure: 0.3MPa ·Lamination temperature: 60°C ·Lamination speed: 0.5 mm / sec ·Number of reciprocations: 1 reciprocation Then, the singulated chip (bump height 210 µm, bump pitch 400 µm, chip size 6 mm × 6 mm, chip thickness 0.5 mm, having a bump-free region of 2400 µm × 2400 µm at the center) was pressed into the thermosetting resin film of the test sample using a pressurizing apparatus ("HTB-MM" from Alpha Design Co., Ltd.). Inside the pressurizing apparatus, a laminated structure was configured by stacking a copper plate (thickness 1 mm) as a temperature controller, a test sample (glass (thickness 1 m), laminated film (thickness 0.225 mm)), a chip (thickness 0.5 mm), and an aluminum foil (0.1 mm) in this order from the bottom, this structure was placed on a suction stage with the copper plate as the lowermost layer, and the chip was pressed from above by a head through the aluminum foil to be pushed into the laminated film formed by stacking the thermosetting resin film. The glass and the copper plate were used in an adhered state. The pressing conditions by the pressurizing apparatus are shown below. (Pressing conditions) ·Load control ·Load: 250 N ·Load time: 10 sec ·Height: 3.0 mm (This value is determined in consideration of the thickness of the laminated structure inside the pressurizing apparatus.) ·Suction stage temperature: 30°C

[0199] After the pressing was completed, the chip was observed through the glass with a digital microscope ("VHX-7000" manufactured by Keyence Corporation), and it was evaluated whether air bubbles were mixed into the 2400 µm × 2400 µm bump-free region at the center of the chip. In this example, samples with no mixed air bubbles were regarded as acceptable. Furthermore, the glass was placed upright, and the chip was observed from the side using a digital microscope (Keyence Corporation's "VHX-7000") to evaluate whether there was a gap between the chip and the thermosetting resin film (whether a bump was visible between the chip and the thermosetting resin film). In this example, chips without gaps were considered acceptable. The absence of gaps indicates good filling of the thermosetting resin film, meaning that the thermosetting resin film is filled all the way to the edge of the chip.

[0200] <Evaluation 4: Evaluation of adhesiveness using a roller-type laminator> Using the test samples and chips prepared in Evaluation 3, the thermosetting resin film of the test sample and the chips were attached using a roller-type laminator under the following conditions. (Attachment conditions) • Laminating device: Desktop laminator (Product name: "LPD3212", manufactured by Fujipla Co., Ltd.) Roller temperature: 80℃ • Application speed: 0.1 mm / min • Number of round trips: 1 round trip After application, the chips were observed through glass using a digital microscope (Keyence Corporation's "VHX-7000") to evaluate whether air bubbles were present in the 2400 μm × 2400 μm bump-free region in the center of the chip. In this example, chips without air bubbles were considered acceptable.

[0201] The evaluation results are shown in Table 1. In Table 1, a rating of A indicates a pass, and a rating of B indicates a fail.

[0202] [Table 1]

[0203] From Table 1, the following can be seen. The results shown in Examples 1 to 5 indicate that when the storage modulus G' of the thermosetting resin film at 30°C before curing is 3.5 MPa or less, good adhesion is achieved by pressing the entire surface simultaneously. In contrast, the results shown in Comparative Examples 1 to 4 indicate that when the storage modulus G' of the thermosetting resin film at 30°C before curing exceeds 3.5 MPa, good adhesion cannot be achieved by pressing the entire surface simultaneously. Furthermore, when using a roller-type laminator for application, the application properties were good in all of Examples 1-5 and Comparative Examples 1-4, and no significant differences were observed. [Explanation of Symbols]

[0204] 1a, 1b, 1c Composite Sheet 10 Base material 11 Buffer layer 12 Intermediate delamination layer 13. Film for forming protective film 20 components (chips) 21. Protruding electrodes (bumps) 80. Tips with protruding electrodes (tips with bumps) (x) Curable resin film (y) Support sheet 30 Pressurizing device 31 Adsorption Stage 32 heads

Claims

1. A protective film-forming film used to form a protective film on the surface where a protruding electrode is formed of a member with a protruding electrode, The protective film is a curable resin film (x) having a storage modulus G' of 3.5 MPa or less at 30°C before curing.

2. The protective film forming film according to claim 1, wherein the curable resin film (x) has a breaking energy of 2.6 J or less at 23°C before curing.

3. The protective film-forming film according to claim 1 or 2, wherein the curable resin film (x) has a storage modulus G' of 1,000 Pa or more at 30°C before curing.

4. The protective film forming film according to claim 1 or 2, wherein the curable resin film (x) is a thermosetting resin film (x1).

5. The protective film-forming film according to claim 4, wherein the thermosetting resin film (x1) contains a flexible epoxy resin.

6. The protective film forming film according to claim 1 or 2, wherein the protective film forming film and the protruding electrode forming surface of the member with the protruding electrode are placed facing each other, and the entire surface of the member with the protruding electrode is simultaneously pressed into the protective film forming film, thereby attaching the protective film forming film to the protruding electrode forming surface.

7. A composite sheet for forming a protective film, wherein the protective film-forming film and the support sheet described in claim 1 or 2 are laminated together.

8. A method for manufacturing a semiconductor device, comprising forming a protective film on the protruding electrode forming surface of a member with a protruding electrode using the protective film forming film described in claim 1 or 2, Step (S1) involves placing the protective film-forming film and the protruding electrode-forming surface of the member with the protruding electrode facing each other, and simultaneously pressing the entire surface of the member with the protruding electrode into the protective film-forming film, thereby attaching the protective film-forming film to the protruding electrode-forming surface. The process of curing the protective film (S2), A method for manufacturing a semiconductor device, including the method described above.

9. The method for manufacturing a semiconductor device according to claim 8, wherein the member with the protruding electrode is a semiconductor chip with a protruding electrode.

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