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

Abstract

The present invention provides a protective film-forming film used to form a protective film on the protruding electrode surface of a member with a protruding electrode, and which can effectively suppress the occurrence of warping of the member with the protective film. [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 is a curable resin film (x) having a glass transition temperature (Tg) of 40°C or less before curing.

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] However, when a protective film, such as a thermosetting resin layer, is applied to a semiconductor wafer or other component, and then the protective film is cured, warping may occur in the component with the protective film. In recent years, due to the increasing complexity of semiconductor processes and the increasing size and thinning of semiconductor wafers and other components, warping of components with protective films has become more likely than before. If a component with a protective film warps, it may cause poor suction when transporting the component using a suction conveyor, making it difficult to carry out the next process. Alternatively, insufficient suction may cause the component to fall during transport, potentially damaging the component with the protective film.

[0006] Therefore, the object of the present invention is to provide a protective film-forming film used to form a protective film on the protruding electrode-forming surface of a member with a protruding electrode, a protective film-forming film, a protective film-forming composite sheet, and a method for manufacturing a semiconductor device, which can effectively suppress the occurrence of warping of the member with the protective film. [Means for solving the problem]

[0007] The present invention provides the following [1] to [7]. [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 glass transition temperature (Tg) of 40°C or less before curing. [2] The curable resin film (x) is the protective film for forming a protective film as described in [1] above, wherein the glass transition temperature (Tg) before curing is 10°C or higher. [3] The protective film forming film according to [1] or [2] above, wherein the curable resin film (x) is a thermosetting resin film (x1). [4] The thermosetting resin film (x1) is the protective film according to [3] above, wherein the thermosetting resin film (x1) contains a flexible epoxy resin. [5] 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 [4] above are laminated together. [6] A method for manufacturing a semiconductor device, comprising the step of forming a protective film on the protruding electrode surface of a member with a protruding electrode using a protective film described in any one of [1] to [4] above. [7] The member with the protruding electrode is a semiconductor wafer having a protruding electrode forming surface equipped with a protruding electrode, and includes the following steps (S1) to (S4): • Step (S1): A step of preparing a semiconductor chip manufacturing wafer in which grooves, which are intended to be divided lines, are formed on the protruding electrode formation surface of the semiconductor wafer without reaching the back surface. Step (S2): A step in which the protective film forming film is attached to the protruding electrode formation surface of the semiconductor chip manufacturing wafer, covering the protruding electrode formation surface of the semiconductor chip manufacturing wafer with the protective film forming film, and embedding the protective film forming film into the grooves formed in the semiconductor chip manufacturing wafer. • Step (S3): A step to cure the protective film-forming film to obtain a wafer for manufacturing semiconductor chips with a protective film. • Step (S4): A step in which the wafer for fabricating the semiconductor chip with the protective film is divided into individual pieces along the planned division line to obtain a semiconductor chip in which at least the surface where the protruding electrodes are formed and the sides are covered with the protective film. Furthermore, the method for manufacturing a semiconductor device according to [6] above, further comprising the following step (S-BG) after step (S2) and before step (S3), after step (S3) and before step (S4), or in step (S4). • Process (S-BG): A process for grinding the back surface of the semiconductor chip manufacturing wafer. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a protective film-forming film used to form a protective film on the protruding electrode-forming surface of a member with a protruding electrode, which can effectively suppress the occurrence of warping of the member with the protective film, a protective film-forming composite sheet, and a method for manufacturing a semiconductor device. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view showing an example of the composite sheet for forming a protective film of the present embodiment. [Figure 2] This is a schematic cross-sectional view showing another example of the composite sheet for forming a protective film of the present embodiment. [Figure 3] This is a schematic cross-sectional view showing still another example of the composite sheet for forming a protective film of the present embodiment. [Figure 4] This is a schematic cross-sectional view showing a part of the method for manufacturing a semiconductor device according to the first aspect of the present embodiment. [Figure 5] This is a schematic cross-sectional view showing a part of the method for manufacturing a semiconductor device according to the first aspect of the present embodiment. [Figure 6] This is a schematic cross-sectional view showing a part of the method for manufacturing a semiconductor device according to the first aspect of the present embodiment. [Figure 7] This is a schematic cross-sectional view showing a part of the method for manufacturing a semiconductor device according to the first aspect of the present embodiment. [Figure 8] In the method for manufacturing a semiconductor device according to the second aspect of the present embodiment, this is a schematic cross-sectional view showing an example of the wafer for producing semiconductor chips prepared in step (S1). [Figure 9] This is a diagram showing an outline of step (S2) in the method for manufacturing a semiconductor device according to the second aspect of the present embodiment. [Figure 10] This is a diagram showing an outline of step (S3) in the method for manufacturing a semiconductor device according to the second aspect of the present embodiment. [Figure 11] This is a diagram showing an outline of step (S4) in the method for manufacturing a semiconductor device according to the second aspect of the present embodiment. [Figure 12] This is a diagram showing an outline of step (S-BG) in the method for manufacturing a semiconductor device according to the second aspect of the present embodiment. [Mode for Carrying Out the Invention]

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

[0011] In this specification, the lower and upper limits described in steps for a preferred numerical range (e.g., range of content, etc.) can be combined independently. 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 arrive at "10 to 60".

[0012] In this specification, "energy beam" means an electromagnetic wave or charged particle beam that has an energy quantum. Examples of energy beams include ultraviolet rays, radiation, and electron beams. Ultraviolet rays can be irradiated using electrodeless lamps, high-pressure mercury lamps, metal halide lamps, xenon lamps, black lights, LED lamps, etc. Electron beams can be irradiated using those generated by electron accelerators, etc. Furthermore, in this specification, "energy ray curability" means the property of hardening by irradiation with energy rays, and "thermosetting property" means the property of hardening by heating.

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

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

[0015] In this specification, the "thickness" of an object means the total thickness of the object as a whole. For example, if the object consists of multiple layers, it means the total thickness of all the layers that make up the object. In this specification, unless otherwise specified, the "thickness" of an object refers to the average value of the thickness measured at five randomly selected locations on the object, and can be obtained using a constant-pressure thickness measuring instrument in accordance with JIS K 7130:1999.

[0016] In this specification, "solid content" or "active ingredient" refers to the components of the composition in question, excluding diluting solvents such as water and organic solvents.

[0017] The mechanism of action described herein is speculative and does not limit the mechanism by which the present invention achieves its effects.

[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 glass transition temperature (Tg) of 40°C or less before curing. The inventors of the present invention, in order to solve the above problems, conducted diligent research and found that the glass transition temperature (Tg) of the curable resin film (x) used as a protective film-forming film greatly affects the amount of warping that occurs when the protective film-forming film is applied to the protruding electrode-forming surface of a member with protruding electrodes and cured. They then found that by using a curable resin film (x) with a glass transition temperature (Tg) of 40°C or less before curing, it is possible to effectively suppress the warping that occurs when the protective film-forming film is applied to the protruding electrode-forming surface of a member with protruding electrodes and cured. Furthermore, if a curable resin film (x) with a glass transition temperature (Tg) exceeding 40°C before curing is used as the protective film, warping is likely to occur when the protective film is applied to the protruding electrode surface of the protruding electrode-equipped member and cured.

[0020] Here, from the viewpoint of making it easier to suppress the occurrence of warping, the glass transition temperature (Tg) of the curable resin film (x) before curing is preferably 35°C or lower, more preferably 30°C or lower, even more preferably 25°C or lower, and even more preferably 20°C or lower. Furthermore, from the viewpoint of suppressing the bleeding of the curable resin film (x), the glass transition temperature (Tg) of the curable resin film (x) before curing is preferably 10°C or higher. The glass transition temperature (Tg) of the curable resin film (x) before curing can be measured by the method described in the examples below. Furthermore, in this embodiment, "before curing" means the state before the curable resin film (x) is subjected to heat curing or energy ray curing. For example, a curable resin composition (x-1) described later that has been dried (drying temperature 70-130°C, drying time 10 seconds-5 minutes) is also included in the "before curing" curable resin film (x).

[0021] The glass transition temperature (Tg) of the curable resin film (x) before curing can be adjusted to the above range by adjusting one or both of the types and contents of the components contained in the curable resin composition for forming the curable resin film (x). Here, a particularly effective method for adjusting the glass transition temperature (Tg) of the curable resin film (x) before curing to the above range is, for example, using a flexible epoxy as the thermosetting component (B) described later. However, the method for controlling the glass transition temperature (Tg) of the curable resin film (x) before curing is not limited to these.

[0022] The curable resin film (x) may consist of only one layer or two or more layers. If the curable resin film (x) consists of multiple layers, these layers may be identical or different from each other, and the combination of these layers is not particularly limited.

[0023] The thickness of the protective film is not particularly limited, but is preferably 10 to 70 μm, more preferably 15 to 60 μm, and even more preferably 15 to 50 μm. When the thickness of the protective film is greater than or equal to the lower limit mentioned above, it is easier to produce a sheet with high in-plane uniformity, and a protective film with higher protective performance tends to be formed. Conversely, when the thickness of the protective film is less than or equal to the upper limit mentioned above, excessive thickness of the protective film is suppressed, making it easier to achieve good bump penetration. The thickness of the protective film can be adjusted based on the relationship between the thickness of the protective film and the thickness of the protective film formed by curing the protective film, as well as information such as the height of the protruding electrodes on the component with the protruding electrodes to be used.

[0024] The curable resin film (x) used as a protective film-forming film in this embodiment will be described in detail below, including the method for adjusting the glass transition temperature (Tg) of the curable resin film (x) before curing.

[0025] <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 glass transition temperature (Tg), the thermosetting resin film (x1) is preferred. The thermosetting resin film (x1) and the energy ray curable resin film (x2) will be described below.

[0026] (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.

[0027] (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.

[0028] 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.

[0029] -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.

[0030] 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).

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] -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.

[0036] -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.

[0037] [ka]

[0038] (In the formula, l, m, and n are each an independent integer greater than or equal to 1.)

[0039] 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.

[0040] 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".

[0041] The ratio of three or more monomers that make up the polyvinyl acetal resin (preferably polyvinyl butyral) can be arbitrarily selected.

[0042] In the thermosetting resin film (x1) and the thermosetting resin composition (x1-1), the content of polymer component (A) is preferably 2 to 30% by mass, more preferably 3 to 25% by mass, and even more preferably 3 to 15% by mass, based on the total amount of active ingredients.

[0043] 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).

[0044] (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.

[0045] 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 easily suppressed.

[0046] 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.

[0047] -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 easily adjusting the glass transition temperature (Tg) of the thermosetting resin film (x1) before curing to 40°C or lower, 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.

[0048] 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.

[0049] 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.

[0050] 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, polyoxyalkernylene group, and polyoxyalkylynylene group is preferably 2 to 4, more preferably 3, from the viewpoint of availability, improvement of the stability of the flexible epoxy resin, ease of reducing the glass transition temperature, and improvement of the embedding ability of the protruding electrode. 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 (2), 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.

[0051] 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.

[0052] The epoxy equivalent of the solid epoxy resin is preferably 150 to 450 g / eq, and more preferably 150 to 400 g / eq.

[0053] 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).

[0054] 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.

[0055] -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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] -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.

[0062] 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.

[0063] 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.

[0064] -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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] -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.

[0070] 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.

[0071] (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.

[0072] 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.

[0073] • 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.

[0074] 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.

[0075] 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).

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] • 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.

[0087] The energy ray curable compound (e12) preferably has 1 to 5 energy ray curable groups per molecule, and more preferably 1 to 2.

[0088] 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.

[0089] 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.

[0090] 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%.

[0091] 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.

[0092] 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).

[0093] 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.

[0094] (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.

[0095] 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.

[0096] 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.

[0097] 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).

[0098] The compound (e2) preferably has a weight-average molecular weight of 100 to 30,000, and more preferably 300 to 10,000.

[0099] 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.

[0100] 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.

[0101] 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).

[0102] -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).

[0103] 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.

[0104] 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.

[0105] 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).

[0106] -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.

[0107] 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.

[0108] -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).

[0109] -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.

[0110] (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)".

[0111] -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.

[0112] 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).

[0113] - 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.

[0114] 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.

[0115] 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).

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] Examples of non-acrylic monomers that constitute the acrylic polymer (β-1) include olefins such as ethylene and norbornene; vinyl acetate; and styrene.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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).

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] -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.

[0135] -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.

[0136] (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.

[0137] <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 glass transition temperature (Tg) of 40°C or less 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.

[0138] (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. The base material 10 may also be a release sheet with a release surface.

[0139] (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.

[0140] (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.

[0141] (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.

[0142] 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.

[0143] 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.

[0144] -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).

[0145] -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).

[0146] 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.

[0147] 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.

[0148] -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.

[0149] -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.

[0150] -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.

[0151] -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.

[0152] -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.

[0153] -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.

[0154] (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.

[0155] 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.

[0156] 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.

[0157] 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.

[0158] (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.

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] The substrate may be transparent or opaque, may be colored depending on the purpose, or may have other layers deposited on it.

[0164] 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.

[0165] <Method for 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.

[0166] 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.

[0167] A composite sheet comprising layers other than those described above can be manufactured by adding or omitting steps as appropriate in the manufacturing method described above, so that the stacking positions of each layer are at desired positions.

[0168] [Method for manufacturing a semiconductor device according to the first embodiment] The first embodiment of the semiconductor device manufacturing method includes a step of forming a protective film on the protruding electrode formation surface of a member with protruding electrodes using a protective film forming film. In the first embodiment of the semiconductor device manufacturing method, it is preferable to perform the step of forming a protective film on the protruding electrode formation surface of a member with protruding electrodes using a protective film forming composite sheet. Here, taking as an example the case where the member with protruding electrodes is a semiconductor wafer with bumps and the surface on which the protruding electrodes are formed is the surface on which the bumps are formed, the manufacturing method of the semiconductor device according to the first embodiment of this embodiment is preferably a manufacturing method that includes the following steps 1 to 5. Step 1: The step of attaching the protective film-forming film of the protective film-forming composite sheet of this embodiment to the bump-forming surface of a semiconductor wafer, causing the tops of the bumps to protrude from the protective film-forming film, thereby laminating the protective film-forming composite sheet onto the semiconductor wafer (hereinafter also referred to as the "attachment step"). Step 2: A step to remove layers other than the protective film-forming film from the composite sheet laminated in Step 1 (hereinafter also referred to as the "removal step"). Step 3: A step to form a protective film by curing a protective film-forming film on a semiconductor wafer (hereinafter also referred to as the "curing step"). Step 4: A step to manufacture semiconductor chips by dividing the semiconductor wafer after Step 3 (hereinafter also referred to as the "dividing step"), and a step to cut the protective film after Step 3 (hereinafter also referred to as the "cutting step"). Step 5: The process of mounting the semiconductor chip with a protective film onto the substrate using a flip-chip connection (hereinafter also referred to as the "mounting process"). The following explains each process with reference to the diagrams. In Figures 4 to 7, the protective film 13 is synonymous with the curable resin film (x). Furthermore, Figures 4 to 7 describe an embodiment using a composite sheet 1 in which a substrate 10, a buffer layer 11, an intermediate release layer 12, and a protective film-forming film 13 are laminated in this order. However, the method for manufacturing a semiconductor device according to the first embodiment of this embodiment is not limited to this embodiment, and composite sheets with other configurations may be used, or only the protective film-forming film 13 may be used. Furthermore, although bumps will be used as an example of protruding electrodes in the following explanation, other types of protruding electrodes may, of course, be used in this invention.

[0169] Examples of semiconductor wafers include semiconductor wafers on which circuits such as wiring, capacitors, diodes, and transistors are formed on the surface. The material of the wafer is not particularly limited and examples include silicon wafers, silicon carbide wafers, compound semiconductor wafers, glass wafers, and sapphire wafers. Furthermore, while the size of the semiconductor wafer is not particularly limited, from the viewpoint of improving batch processing efficiency, it is usually 8 inches (200 mm in diameter) or larger, and preferably 12 inches (300 mm in diameter) or larger. The shape of the semiconductor wafer is not limited to circular, and may be square, rectangular, or other angular shapes. In the case of an angular semiconductor wafer, from the viewpoint of improving batch processing efficiency, it is preferable that the length of the longest side is equal to or greater than the above-mentioned size (diameter). The thickness of the semiconductor wafer is not particularly limited, but from the viewpoint of making it easier to suppress warping due to shrinkage when curing the curable resin film (x), and from the viewpoint of reducing the amount of grinding on the back surface of the semiconductor wafer in a later process and shortening the time required for back surface grinding, it is preferably 10 μm to 2,000 μm, more preferably 15 μm to 1,500 μm, and even more preferably 20 μm to 1,000 μm. It may also be 800 μm or less, or 700 μm or less.

[0170] <Step 1: Pasting Process> Figure 4 is a schematic cross-sectional view illustrating the application process. Figures 4(a) and (b) show the process of attaching the protective film-forming composite sheet 1 to the bump-forming surface 20a of the semiconductor wafer 20. In the bonding process, for example, first, as shown in Figure 4(a), the composite sheet 1 for forming the protective film is positioned so that the protective film 13 faces the bump-forming surface 20a of the semiconductor wafer 20. Next, the protective film-forming film 13 is brought into contact with the bumps 21 on the semiconductor wafer 20, and the protective film-forming composite sheet 1 is pressed against the semiconductor wafer 20. By pressing, the protective film-forming film 13 is sequentially pressed onto the surface of the bumps 21 and the bump-forming surface 20a of the semiconductor wafer 20. When the protective film-forming composite sheet 1 is pressed onto the semiconductor wafer 20, the protective film-forming film 13 is subjected to pressure from the bumps 21 through the buffer layer 11, causing it to tear. Finally, as shown in Figure 4(b), the upper part of the bumps 21 protrudes through the protective film-forming film 13.

[0171] The height of the bump 21 is not particularly limited, but is preferably 120 to 300 μm, more preferably 150 to 270 μm, and even more preferably 180 to 240 μm. In this specification, "bump height" means the height of the bump at the highest point of the bump from the bump-forming surface.

[0172] The width of the bump 21 is not particularly limited, but is preferably 170 to 350 μm, more preferably 200 to 320 μm, and even more preferably 230 to 290 μm. In this specification, "bump width" means the maximum length of a line segment obtained by drawing a straight line between two different points on the bump surface when the bump is viewed from above in a plan view from a direction perpendicular to the bump-forming surface.

[0173] The distance between adjacent bumps 21 is not particularly limited, but is preferably 250 to 800 μm, more preferably 300 to 600 μm, and even more preferably 350 to 500 μm. In this specification, "distance between adjacent bumps" means the minimum distance between the surfaces of adjacent bumps.

[0174] As a method for pressing the protective film-forming composite sheet 1 onto the semiconductor wafer 20, known methods for pressing and attaching various sheets to an object can be applied, such as using a roller-type laminator. The heating temperature when pressing the protective film-forming composite sheet 1 onto the semiconductor wafer 20 is not particularly limited and may be, for example, 80 to 100°C, and preferably 85 to 95°C. The pressure applied when pressing the protective film-forming composite sheet 1 onto the semiconductor wafer 20 is not particularly limited and may be, for example, 0.1 to 1.5 MPa, and preferably 0.3 to 1 MPa. The speed at which the protective film-forming composite sheet 1 is attached to the semiconductor wafer 20 is not particularly limited, but is usually around 2 mm / s.

[0175] After the bonding process, the side of the semiconductor wafer 20 opposite to the bump-forming surface 20a (the back side) may be ground as needed, and further, another protective film-forming composite sheet (not shown) may be attached to the back side after grinding.

[0176] <Step 2: Removal step> Figure 5 is a schematic cross-sectional view illustrating the removal process. After the bonding process, as shown in Figure 5, layers other than the protective film forming film 13 are removed from the protective film forming composite sheet 1 to obtain a semiconductor wafer 30 with a protective film forming film, which comprises a semiconductor wafer 20 and a protective film forming film 13 provided on the bump-forming surface 20a of the semiconductor wafer 20. Layers other than the protective film 13 can be removed by known methods.

[0177] <Process 3: Curing process> Figure 6 is a schematic cross-sectional view illustrating the curing process. After the removing step, as shown in Figure 6, the protective film forming film 13 is cured to form a protective film 13' formed by curing the protective film forming film 13 on the bump forming surface 20a of the semiconductor wafer 20. Thereby, the semiconductor wafer 40 with a protective film having the protective film 13' on the bump forming surface 20a of the semiconductor wafer 20 is obtained. The conditions for curing the protective film forming film are not particularly limited, and may be appropriately adjusted and determined according to the type of materials constituting the protective film forming film and the like. As the conditions for performing thermal curing, the curing temperature is preferably 90°C to 200°C (more preferably 110°C to 170°C, still more preferably 120°C to 140°C), and the curing time is preferably 1 hour to 5 hours. As the conditions for performing curing by energy ray irradiation, the conditions are appropriately set according to the type of energy ray used. For example, when ultraviolet rays are used, the illuminance is preferably 170 mw / cm 2 ~250mw / cm 2 , and the light quantity is preferably 300 mJ / cm 2 ~3,000mJ / cm 2 . Here, in the process of curing the curable resin film (x) to form the cured resin film (r), from the viewpoint of removing bubbles and the like that may enter when the groove portion 23 is filled with the first curable resin film (X1) in the step (S2), the curable resin film (x) is preferably a thermosetting resin film. In the present embodiment, since the curable resin film (x) having a glass transition temperature (Tg) of 40°C or lower before curing is used as the protective film forming film 13, shrinkage is suppressed in the process of curing the protective film forming film 13, and the occurrence of warpage of the semiconductor wafer 40 with a protective film provided with the protective film 13' can be effectively suppressed.

[0178] <Step 4: Dividing Step, Cutting Step> Figure 7 is a schematic cross-sectional view for explaining the dividing step and the cutting step. After the curing process, as shown in Figure 7, the semiconductor wafer 20 is divided in the splitting process to produce a semiconductor chip 50. In the cutting process, the protective film 13' is cut to form the protective film 130' after cutting. This results in a semiconductor chip 60 with a protective film, having the protective film 130' after cutting on the bump-forming surface of the semiconductor chip 50.

[0179] The dividing and cutting processes can be carried out by known methods. The order in which the dividing and cutting processes are performed is not particularly limited, but it is preferable to perform the dividing and cutting processes simultaneously or in that order. When the dividing and cutting processes are performed in this order, for example, the dividing process may be performed by a known dicing method, and then the cutting process may be performed immediately afterward. Dicing can be performed by providing a dicing sheet (not shown) on the back surface of the semiconductor wafer 20 (which may be the back surface after grinding). In the cutting process, the protective film 13' is cut along the planned or already divided portion of the semiconductor wafer 20 (in other words, the outer periphery of the semiconductor chip 40).

[0180] <Process 5: Assembly Process> In the mounting process, the semiconductor chip 60 with the protective film obtained in the curing process is flip-chip connected to the substrate at the top of the bump 21 (not shown). At this time, the semiconductor chip 60 with the protective film is connected to the circuit formation surface of the substrate. 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.

[0181] [Method for manufacturing semiconductor manufacturing apparatus according to the second embodiment] A second embodiment of this invention provides a method for manufacturing a semiconductor device, wherein the member with a protruding electrode is a semiconductor wafer having a protruding electrode forming surface equipped with a protruding electrode, and includes the following steps (S1) to (S4). • Step (S1): A step of preparing a semiconductor chip manufacturing wafer in which grooves, which are intended to be divided lines, are formed on the protruding electrode formation surface of the semiconductor wafer without reaching the back surface. Step (S2): A step in which the protective film forming film is attached to the protruding electrode formation surface of the semiconductor chip manufacturing wafer, covering the protruding electrode formation surface of the semiconductor chip manufacturing wafer with the protective film forming film, and embedding the protective film forming film into the grooves formed in the semiconductor chip manufacturing wafer. • Step (S3): A step to cure the protective film-forming film to obtain a wafer for manufacturing semiconductor chips with a protective film. • Step (S4): A step in which the wafer for fabricating the semiconductor chip with the protective film is divided into individual pieces along the planned division line to obtain a semiconductor chip in which at least the surface where the protruding electrodes are formed and the sides are covered with the protective film. Furthermore, the following step (S-BG) is included after step (S2) and before step (S3), after step (S3) and before step (S4), or during step (S4). • Process (S-BG): A process for grinding the back surface of the semiconductor chip manufacturing wafer.

[0182] The following explains each step with reference to the diagrams. Figures 8 to 11 describe an embodiment using a composite sheet α1 in which a support sheet (y) and a curable resin film (x) are laminated in this order. However, the method for manufacturing a semiconductor device according to the second embodiment of this embodiment is not limited to this embodiment, and composite sheets with other configurations may be used, or only a curable resin film (x) may be used. Furthermore, in the following explanation, bumps will be used as an example of protruding electrodes, but of course, other types of protruding electrodes may be used in this embodiment.

[0183] <Process (S1)> A schematic cross-sectional view of an example of a semiconductor wafer prepared in process (S1) is shown in Figure 8. In step (S1), a semiconductor wafer 70 for semiconductor chip fabrication is prepared, in which grooves 23, which are intended to be divided lines, are formed on the bump-forming surface 20a of a semiconductor wafer 20 having bumps 21, without reaching the back surface 20b.

[0184] The shape of the bump 21 is not particularly limited and can be any shape as long as it can be in contact with and fixed to electrodes on the substrate for chip mounting. For example, although the bump 21 is spherical in Figure 8, the bump 21 may be a spheroid. This spheroid may be, for example, a spheroid stretched perpendicularly to the bump-forming surface 20a of the wafer 20, or a spheroid stretched horizontally to the bump-forming surface 20a of the wafer 20. The bump 21 may also be pillar-shaped.

[0185] The height of the bump 21, the width of the bump 21, and the distance between adjacent bumps 21 are not particularly limited, but examples include the height of the bump 21, the width of the bump 21, and the distance between adjacent bumps 21 as described in the first embodiment of the semiconductor device manufacturing method.

[0186] The type, size, and thickness of the wafer 20 are not particularly limited, but examples include the semiconductor wafers listed in the semiconductor device manufacturing method of the first embodiment.

[0187] In step (S1), a plurality of grooves 23 are formed in a grid pattern on the bump-forming surface 20a of the semiconductor chip manufacturing wafer 70, which is prepared as the planned division lines when the semiconductor chip manufacturing wafer 70 is divided into individual pieces. The plurality of grooves 23 are notches formed when the blade-first dicing method (Dicing Before Grinding) is applied, and are formed to a depth shallower than the thickness of the wafer 20, so that the deepest part of the groove 23 does not reach the back surface 20b of the wafer 20. The plurality of grooves 23 can be formed by dicing using a conventionally known wafer dicing apparatus equipped with a dicing blade. It should be noted that the plurality of groove portions 23 may be formed so that the semiconductor chips to be manufactured have a desired size and shape. The size of the semiconductor chip is usually about 0.5 mm × 0.5 mm to 1.0 mm × 1.0 mm, but is not limited to this size.

[0188] The width of the groove portion 23 is preferably from 10 μm to 2,000 μm, more preferably from 30 μm to 1,000 μm, still more preferably from 40 μm to 500 μm, and even more preferably from 50 μm to 300 μm, from the viewpoint of improving the embedding property of the curable resin film (x).

[0189] The depth of the groove portion 23 is adjusted according to the thickness of the wafer to be used and the required chip thickness, and is preferably from 30 μm to 700 μm, more preferably from 60 μm to 600 μm, and still more preferably from 100 μm to 500 μm.

[0190] The wafer 70 for manufacturing semiconductor chips prepared in the step (S1) is subjected to the step (S2).

[0191] <Step (S2)> The outline of the step (S2) is shown in Figure 9. In the step (S2), the curable resin film (x) is pressed and attached to the bump forming surface 20a of the wafer 70 for manufacturing semiconductor chips. In Figure 9, the curable resin film (x) of the first composite sheet (α1) is pressed and attached to the bump forming surface 21a of the wafer 30 for manufacturing semiconductor chips, with the curable resin film (x) serving as the attaching surface.

[0192] By the step (S2), as shown in Figure 9, the bump forming surface 20a of the wafer 70 for manufacturing semiconductor chips is covered with the curable resin film (x), and the curable resin film (x) is embedded into the groove portions 23 formed in the wafer 70 for manufacturing semiconductor chips.

[0193] The pressing force applied when attaching the curable resin film (x) to the semiconductor chip wafer 70 is preferably 1 kPa to 200 kPa, more preferably 5 kPa to 150 kPa, and even more preferably 10 kPa to 100 kPa, from the viewpoint of ensuring good embedding of the curable resin film (x) into the grooves 23. Furthermore, the pressing force applied when attaching the curable resin film (x) to the semiconductor chip wafer 70 may be appropriately varied from the initial stage to the final stage of attachment. For example, from the viewpoint of improving the embedding of the curable resin film (x) into the grooves 23, it is preferable to keep the pressing force low at the initial stage of attachment and gradually increase it.

[0194] Furthermore, when attaching the curable resin film (x) to the semiconductor chip wafer 70, if the curable resin film (x) is a thermosetting resin film (x1), it is preferable to heat it in order to improve the embedding properties of the thermosetting resin film (x1) into the grooves 23. The specific heating temperature (application temperature) is preferably 50°C to 150°C, more preferably 60°C to 130°C, and even more preferably 70°C to 110°C. Note that the heat treatment performed on the curable resin film (x) is not included in the curing treatment of the curable resin film (x).

[0195] Furthermore, when attaching the curable resin film (x) to the semiconductor chip wafer 70, it is preferable to do so under reduced pressure. This creates negative pressure in the grooves 23, making it easier for the curable resin film (x) to spread throughout the grooves 23. As a result, the embedding of the curable resin film (x) into the grooves 23 becomes better. The specific pressure of the reduced pressure environment is preferably 0.001kPa to 50kPa, more preferably 0.01kPa to 5kPa, and even more preferably 0.05kPa to 1kPa.

[0196] After the bonding process, the support sheet (y) is removed from the first composite sheet (α1). The support sheet (y) can be removed by known methods.

[0197] <Process (S3)> A schematic of process (S3) is shown in Figure 10. In step (S3), the curable resin film (x) is cured to obtain a wafer 70 for semiconductor chip fabrication with a cured resin film (r) attached. The cured resin film (r) formed by curing the curable resin film (x) becomes stronger than the curable resin film (x) at room temperature. Therefore, the bump neck is well protected by forming the cured resin film (r). In this embodiment, a curable resin film (x) having a glass transition temperature (Tg) of 40°C or less before curing is used as the protective film-forming film. As a result, shrinkage is suppressed during the curing process of the protective film-forming film, and the occurrence of warping of the protective film-equipped semiconductor wafer 70, which has a cured resin film (r) as the protective film 13', can be effectively suppressed.

[0198] The curable resin film (x) can be cured by either thermal curing or curing by irradiation with energy rays, depending on the type of curable component contained in the curable resin film (x). When performing thermal curing, the curing temperature is preferably 90°C to 200°C (more preferably 110°C to 170°C, and even more preferably 120°C to 140°C), and the curing time is preferably 1 hour to 5 hours. The conditions for curing by energy ray irradiation are set appropriately depending on the type of energy ray used. For example, when using ultraviolet light, the illuminance is preferably 170 mw / cm². 2 ~250mw / cm 2 The light intensity is preferably 300 mJ / cm². 2 ~3,000 mJ / cm 2 That is the case. Here, in the process of curing a curable resin film (x) to form a cured resin film (r), it is preferable that the curable resin film (x) is a thermosetting resin film, from the viewpoint of removing air bubbles and the like that may get trapped when filling the groove portion 23 with the first curable resin film (X1) in step (S2).

[0199] <Process (S4)> A schematic of process (S4) is shown in Figure 11. In step (S4), the portion of the cured resin film (r) of the wafer 70 for semiconductor chip fabrication with the cured resin film (r) that is formed in the groove 23 is cut along the planned division line. Cutting is performed by blade dicing. This makes it possible to obtain a semiconductor chip 80 in which at least the bump-forming surface 20a and the side surface are covered with a cured resin film (r). The semiconductor chip 80 has excellent strength because its bump-forming surface 20a and side surface are covered with a first cured resin film (r1). Furthermore, because the bump-forming surface 20a and side surface are continuously covered with the cured resin film (r) without any breaks, the bonding surface (interface) between the bump-forming surface 20a and the cured resin film (r) is not exposed on the side surface of the semiconductor chip 80. Of the bonding surface (interface) between the bump-forming surface 20a and the cured resin film (r), the exposed portion on the side surface of the semiconductor chip 80 is prone to becoming a starting point for film peeling. In this embodiment, since such exposed portions do not exist in the semiconductor chip 80, film peeling from such exposed portions is less likely to occur during the process of cutting the semiconductor chip wafer 70 to manufacture the semiconductor chip 80, or after manufacturing. Therefore, a semiconductor chip 80 is obtained in which peeling of the cured resin film (r) as a protective film is suppressed.

[0200] Furthermore, in step (S4), when cutting the portion of the cured resin film (r) of the semiconductor chip fabrication wafer 70 with the cured resin film (r) that is formed in the groove 23 along the planned division line, it is preferable that the cured resin film (r) is transparent. Because the cured resin film (r) is transparent, the semiconductor wafer 21 is visible through it, ensuring visibility of the planned division line. Therefore, it becomes easier to cut along the planned division line.

[0201] <Process (S-BG)> A schematic of the process (S-BG) is shown in Figure 12. In the step (S-BG), as shown in (1-a) of FIG. 12, first, with the first composite sheet (α1) attached, the back surface 20b of the wafer 70 for semiconductor chip production is ground. "BG" in FIG. 12 means back grind. Next, as shown in (1-b) of FIG. 12, the support sheet (y) is peeled off from the composite sheet (α1). The grinding amount when grinding the back surface 20b of the wafer 70 for semiconductor chip production may be an amount that at least exposes the bottom of the groove 23 of the wafer 70 for semiconductor chip production, and further grinding may be performed to grind the curable resin film (x) or cured resin film (r) embedded in the groove 23 together with the wafer 70 for semiconductor chip production.

[0202] The above step (S-BG) may be performed after the above step (S2) and before the above step (S3), may be performed after the above step (S3) and before the above step (S4), or may be performed in the above step (S4). Above all, from the viewpoint of making the effects of the present invention easier to exert, it is preferable to perform the step after the above step (S3) and before the above step (S4), or in the above step (S4).

[0203] <Step(T)> The method for manufacturing a semiconductor chip according to the second aspect of the present embodiment preferably further includes the following step (T). Step (T): A step of forming a backside cured resin film (rb) on the back surface of the wafer for semiconductor chip production

[0204] According to the manufacturing method according to the above embodiment, it is possible to obtain the semiconductor chip 80 at least the bump forming surface 20a and the side surfaces of which are covered with the cured resin film (r). However, the back surface of the semiconductor chip 80 is exposed. Therefore, from the viewpoint of protecting the back surface of the semiconductor chip 80 and further improving the strength of the semiconductor chip 80, it is preferable to perform the above step (T).

[0205] More specifically, the above step (T) preferably includes the following step (T1) and the following step (T2) in this order. • Process (T1): A process of attaching a back-side curable resin film (xb) to the back surface of a wafer for semiconductor chip fabrication. • Process (T2): A process to cure the back-side curable resin film (xb) to form a back-side curable resin film (rb).

[0206] In step (T1), a composite sheet for the back surface (α2) is used, which is formed by laminating a support sheet (y2) and a curable resin film for the back surface (xb). In this case, it is preferable that the support sheet (y2) of the composite sheet for the back surface (α2) not only supports the curable resin film for the back surface (xb) but also functions as a dicing sheet. Furthermore, in process (S4), the composite sheet for the back surface (α2) is attached to the back surface 20b of the semiconductor wafer 70 with the cured resin film (r). This allows the support sheet (y2) to function as a dicing sheet when dicing to separate the wafer into individual pieces, making the dicing process easier.

[0207] Here, if process (S3) is performed after process (S-BG), process (T1) may be performed before process (S3), and then process (S3) and process (T2) may be performed simultaneously. In other words, the curable resin film (x) and the curable resin film for the back surface (xb) may be cured together at the same time. This reduces the number of curing treatments.

[0208] <Process (U)> The semiconductor chip manufacturing method according to the second aspect of this embodiment may further include the following step (U). Step (U): A step of removing the hardened resin film (r) covering the top of the bump, or the hardened resin film (r) adhering to a part of the top of the bump, to expose the top of the bump. Exposure treatments to expose the top of the bump include etching treatments such as wet etching and dry etching. Examples of dry etching processes include plasma etching. Furthermore, exposure processing may be performed to retract the protective film until the tops of the bumps are exposed, if the tops of the bumps are not exposed on the surface of the protective film.

[0209] The timing of performing step (U) is not particularly limited as long as the cured resin film (r) is exposed. In addition, step (U) may be performed after step 3 in the semiconductor chip manufacturing method of the first embodiment of this model. [Examples]

[0210] 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.

[0211] [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

[0212] [Manufacturing of thermosetting resin films] A thermosetting resin film was manufactured using the method described below.

[0213] <Raw materials for thermosetting resin films> The raw materials used in the manufacture of the thermosetting resin film are listed below.

[0214] "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")

[0215] "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)-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.

[0216] "Thermosetting agent (B2)" (B2)-1: o-cresol type novolac resin (DIC Corporation's "Phenolite KA-1160")

[0217] "Curing accelerator (C)" (C)-1:2-phenyl-4,5-dihydroxymethylimidazole (Shikoku Chemicals Co., Ltd. "Curesol 2PHZ-PW")

[0218] "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)

[0219] "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")

[0220] [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.

[0221] [Example 2] Thermosetting resin film (x1)-2 was prepared by changing the formulation of thermosetting resin film (x1)-1 as shown in Example 2 of Table 1, and thermosetting resin film (x1)-2 with release films on both sides was obtained.

[0222] [Example 3] Thermosetting resin film (x1)-3 was prepared by changing the formulation of thermosetting resin film (x1)-1 as shown in Example 3 of Table 1, and thermosetting resin film (x1)-3 with double-sided release film was obtained.

[0223] [Example 4] Thermosetting resin film (x1)-4 was prepared by changing the formulation of thermosetting resin film (x1)-1 as shown in Example 4 of Table 1, and thermosetting resin film (x1)-4 with release films on both sides was obtained.

[0224] [Comparative Example 1] Thermosetting resin film (x1')-1 was prepared by changing the formulation of thermosetting resin film (x1)-1 as shown in Comparative Example 1 in Table 1, and thermosetting resin film (x1')-1 with release films on both sides was obtained.

[0225] [Comparative Example 2] Thermosetting resin film (x1')-2 was prepared by changing the formulation of thermosetting resin film (x1)-1 as shown in Comparative Example 2 in Table 1, and thermosetting resin film (x1')-2 with release films on both sides was obtained.

[0226] [Comparative Example 3] Thermosetting resin film (x1')-3 was prepared by changing the formulation of thermosetting resin film (x1)-1 as shown in Comparative Example 3 in Table 1, and thermosetting resin film (x1')-3 with double-sided release film was obtained.

[0227] [evaluation] In this embodiment, the following evaluations 1 to 3 were performed.

[0228] <Evaluation 1: Evaluation of the glass transition temperature of thermosetting resin film before curing> Twenty-two sheets each of the thermosetting resin films (x1)-1 to (x1)-4 and thermosetting resin films (x1')-1 to (x1')-3 prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were prepared. Next, after laminating 22 thermosetting resin films, a test specimen of a protective film with a thickness of 990 μm was prepared by cutting it into a disc shape with a diameter of 25 mm (25 mmφ). The lamination conditions for stacking 22 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

[0229] Then, the glass transition temperature (Tg) was measured for the uncured test specimens. The glass transition temperature (Tg) was measured by the following method. The storage modulus G' was measured at a constant frequency and amplitude over a temperature range from 0°C to 150°C, and the temperature dependence of the storage modulus G' (vertical axis) was evaluated. Subsequently, the temperature at which the material transitions from a rubbery state to a solidified state (glassy state) was determined and defined as the glass transition temperature (Tg). The measurement conditions for the glass transition temperature are shown below. (Measurement conditions for glass transition temperature) • Equipment: Anton Paar "MCR301" ·Measurement frequency: 1Hz • Swing angle: gamma=0.1%

[0230] <Evaluation 2: Evaluation of curvature> An 8-inch circular piece of electrolytic copper foil (35 μm thick, manufactured by Kansai Electronics Industry Co., Ltd.) was cut to size. The release film from the double-sided release film thermosetting resin film prepared in Examples 1-4 and Comparative Examples 1-3 was removed, and the film was heated and attached so that it came into contact with the copper foil. The heating and application conditions are as follows. (Conditions for heat application) • Equipment: Desktop laminator (Product name: "LPD3212", manufactured by Fujipla Co., Ltd.) • Adhesion pressure: 0.3 MPa • Application temperature: 60℃ • Application speed: 1 mm / second • Number of round trips: 1 round trip Next, the composite sheet for forming a protective film, which had been heat-bonded to the electrolytic copper foil, was cut along the circular copper foil using a cutter to form a test piece. After visually confirming that the test piece was not warped, the release film was removed, leaving only the thermosetting resin film on the test piece. The thermosetting resin film was then formed by heat curing at a temperature of 130°C for 240 minutes. Afterward, the electrolytic copper foil with the thermosetting resin film, which had been allowed to cool to room temperature (25°C), was placed on a horizontal table with the electrolytic copper foil side facing downwards. Tape (Nichiban Co., Ltd., product name "Cellotape (registered trademark) LP-24", tape width 24 mm) was attached to three roughly equal points around the outer circumference of the electrolytic copper foil with the thermosetting resin film, and fixed to the horizontal table. The height between the fixing points with tape (the lift from the horizontal table) was measured, and the maximum value was defined as the warp (unit: mm). In this embodiment, a curvature of 15 mm or less was considered acceptable. A smaller curvature value is preferable.

[0231] <Evaluation 3: Evaluation of bleeding properties> A roll was prepared by winding 50 m of thermosetting resin film with double-sided release film, as prepared in Examples 1-4 and Comparative Examples 1-3, onto a core. The maximum width of the thermosetting resin film seepage from the end of the roll was measured after it was left standing vertically for one week under 30°C conditions, and the amount of seepage was determined.

[0232] The evaluation results are shown in Table 1.

[0233] [Table 1]

[0234] From Table 1, the following can be seen. The results shown in Examples 1 to 4 indicate that when the glass transition temperature (Tg) of the thermosetting resin film before curing is 40°C or lower, the occurrence of warping of the electrolytic copper foil is suppressed. In contrast, the results shown in Comparative Examples 1 to 3 indicate that when the glass transition temperature (Tg) of the thermosetting resin film before curing exceeds 40°C, warping occurs in the electrolytic copper foil. Furthermore, the results shown in Examples 1 to 4 indicate that the thermosetting resin films (x1)-1 to (x1)-4 produced in Examples 1 to 4 all exhibited low leaching and were thermosetting resin films with excellent long-term stability. [Explanation of Symbols]

[0235] 1a, 1b, 1c Composite Sheet (x) Curable resin film (y) Support sheet 10 Base material 11 Buffer layer 12 Intermediate delamination layer 13. Film for forming protective film 20 Semiconductor wafers 21. Protruding electrodes (bumps) 23 Groove 70 Wafers for semiconductor chip fabrication 80 Semiconductor chip with cured resin film (x)'

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 glass transition temperature (Tg) of 40°C or less before curing.

2. The protective film-forming film according to claim 1, wherein the curable resin film (x) has a glass transition temperature (Tg) of 10°C or higher before curing.

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

4. The protective film for forming a protective film according to claim 3, wherein the thermosetting resin film (x1) contains a flexible epoxy resin.

5. 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.

6. A method for manufacturing a semiconductor device, comprising the step of 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.

7. The member with the protruding electrode is a semiconductor wafer having a protruding electrode forming surface equipped with a protruding electrode, and includes the following steps (S1) to (S4): Step (S1): A step to prepare a semiconductor wafer for semiconductor chip fabrication in which grooves, which are intended to be divided lines, are formed on the protruding electrode formation surface of the semiconductor wafer without reaching the back surface. Step (S2): The process of attaching the protective film-forming film to the protruding electrode formation surface of the semiconductor chip manufacturing wafer, covering the protruding electrode formation surface of the semiconductor chip manufacturing wafer with the protective film-forming film, and embedding the protective film-forming film in the grooves formed in the semiconductor chip manufacturing wafer. Step (S3): A step to cure the protective film-forming film to obtain a wafer for manufacturing semiconductor chips with a protective film. Step (S4): A step to obtain a semiconductor chip in which at least the surface on which the protruding electrode is formed and the sides are covered with the protective film, by separating the wafer for fabricating the semiconductor chip with the protective film along the planned division line. Furthermore, the method for manufacturing a semiconductor device according to claim 6, comprising the following step (S-BG) after step (S2) and before step (S3), after step (S3) and before step (S4), or in step (S4). • Process (S-BG): A process for grinding the back surface of the semiconductor chip manufacturing wafer.

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