Protective film forming sheet

Abstract

The present invention addresses the issue of providing a protective film-forming sheet that is capable of suppressing short-circuiting between narrow-pitched bumps. The issue is solved by a protective film-forming sheet that: has a laminated structure comprising a curable resin film (x) and a support sheet (Y); has a plurality of bumps; is used to form a protective film (X) on a bump-formation surface of a semiconductor wafer that fulfills a prescribed requirement that indicates the presence of narrow-pitched bumps; and fulfills a prescribed requirement specified by tensile modulus E'.

Description

[Technical Field]

[0001] The present invention relates to a sheet for forming a protective film. [Background technology]

[0002] Conventionally, when mounting a multi-pin LSI package used in an MPU, gate array, etc. on a printed wiring board, a semiconductor chip with convex electrodes (hereinafter also referred to as "bumps") formed on its connection pads has been used, and the so-called face-down flip-chip mounting method has been adopted in which these bumps are brought face-to-face into contact with corresponding terminals on a chip-mounting substrate and fused or diffused to bond them.

[0003] In recent years, as electronic devices have become smaller, lighter, thinner, and more functional, high-density packaging is also required for the electronic components built in. Patent Documents 1 to 3 propose solder materials with low alpha radiation dose to avoid a problem associated with high-density packaging, namely, the problem of soft errors in which memory contents are rewritten due to the penetration of alpha rays into memory cells of semiconductor integrated circuits. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4472752 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-214040 [Patent Document 3] International Publication No. 2012 / 120982 Brochure Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, with the increasing demand for higher-density packaging of electronic components, there is also an increasing demand for narrower bump pitches on semiconductor chips. However, narrowing the bump pitch on semiconductor chips creates new problems. For example, in the process of electrically connecting a semiconductor chip to a wiring board via ball bumps, the ball bumps can be crushed and spread laterally, causing contact between the ball bumps and resulting in short circuits. Furthermore, to meet the demand for even higher-density packaging, three-dimensional high-density packaging in which semiconductor packages are stacked vertically is also being considered. In this case, the weight of the semiconductor package can gradually crush the ball bumps, potentially resulting in short circuits.

[0006] In light of the above problems, the inventors conducted extensive research and developed a sheet for forming a protective film that can prevent ball bumps from collapsing and spreading laterally. It is also believed that even in semiconductor chips with pillar bumps, bending of the pillar bumps can cause the pillar bumps to come into contact with each other, resulting in a short circuit. The developed sheet was found to be effective in solving such problems with pillar bumps.

[0007] Therefore, an object of the present invention is to provide a sheet for forming a protective film that can suppress short circuits between bumps with narrow pitches. [Means for solving the problem]

[0008] The present inventors have found that the above problems can be solved by the following invention. That is, the present invention relates to the following [1] to [9]. [1] A sheet for forming a protective film having a laminated structure of a curable resin film (x) and a support sheet (Y), The present invention is used to form a protective film (X) on a bump-forming surface of a semiconductor wafer having a plurality of bumps and satisfying the following requirements (α1) to (α2): Requirement (α1): The width of the bump (BM w ) (unit: μm) is 20 μm to 350 μm. Requirement (α2): The pitch of the bumps (BM P ) (unit: μm) and the width of the bump (BM w ) (unit: μm) satisfies the following formula (I). [(BM P ) / (BM w )]≦1.0 (I) A sheet for forming a protective film, which satisfies the following requirements (β1) to (β3): Requirement (β1): The protective film (X) formed by curing the curable resin film (x) has a tensile modulus E' (23°C) at 23°C of 1 x 10 7 Pa~1×10 10 It is Pa. Requirement (β2): The protective film (X) formed by curing the curable resin film (x) has a tensile modulus E' (260°C) at 260°C of 1×10 5 Pa~1×10 8 It is Pa. Requirement (β3): The thickness (X) of the protective film (X) formed by curing the curable resin film (x) at 23°C T ) (unit: μm) and the height of the bump (BM h ) (unit: μm) satisfies the following formula (II). [(X T ) / (BM h )] ≥ 0.2 (II) [2] The sheet for forming a protective film according to [1], further satisfying the following requirement (α3a): Requirement (α3a): The height of the bump (BM h ) and the width of the bump (BM w ) and satisfy the following formula (IIIa): 0.2≦[(BM h ) / (BM w )]≦1.0 (IIIa) [3] The sheet for forming a protective film according to [1], further satisfying the following requirement (α3b): Requirement (α3b): The height of the bump (BM h ) and the width of the bump (BM w ) satisfies the following formula (IIIb): 0.5≦[(BM h) / (BM w )]≦5.0 (IIIb) [4] The sheet for forming a protective film according to any one of [1] to [3], further satisfying the following requirement (α4): Requirement (α4): The height of the bump (BM h ) is 15μm to 300μm [5] The sheet for forming a protective film according to any one of [1] to [4], wherein the support sheet (Y) is a backgrind tape. [6] A method for manufacturing a semiconductor wafer with a protective film, comprising: The method includes the following steps (S1) to (S3): Step (S1): A step of preparing a semiconductor wafer having a bump-forming surface on which a plurality of bumps are provided. Step (S2): A step of adhering the sheet for forming a protective film according to any one of [1] to [5] to the bump-forming surface of the semiconductor wafer while pressing the curable resin film (x) onto the bump-forming surface. Step (S3): A step of curing the curable resin film (x) to form a protective film (X). A method for producing a semiconductor wafer with a protective film, wherein the semiconductor wafer prepared in the step (S1) satisfies the following requirements (α1) to (α2): Condition (α1): The width of the bump (BM w ) (unit: μm) is 20 μm to 350 μm Condition (α2): The pitch of the bumps (BM P ) (unit: μm) and the width of the bump (BM w ) (unit: μm) satisfies the following formula (I): [(BM P ) / (BM w )]≦1.0 (I) [7] A method for producing a semiconductor chip with a protective film, comprising the following steps (T1) to (T2): Step (T1): A step of obtaining a semiconductor wafer with a protective film by carrying out the manufacturing method described in [6]. Step (T2): A step of dividing the semiconductor wafer with the protective film into individual pieces. [8] A method for manufacturing a semiconductor package, comprising the following steps (U1) to (U2): Step (U1): A step of obtaining a semiconductor chip with a protective film by carrying out the manufacturing method described in [7]. Step (U2): A step of electrically connecting the wiring substrate and the semiconductor chip with the protective film via the bumps. [9] The method for manufacturing a semiconductor package according to [8], further comprising step (U3). Step (U3): A step of filling an underfill material between the wiring substrate and the semiconductor chip with the protective film. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a sheet for forming a protective film that can suppress short circuits between bumps with narrow pitches. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view showing the configuration of a sheet for forming a protective film of the present invention. [Figure 2] 1 is a schematic cross-sectional view showing an example of the configuration of a sheet for forming a protective film according to one embodiment of the present invention. [Figure 3] FIG. 2 is a schematic cross-sectional view showing another example of the configuration of the sheet for forming a protective film according to one embodiment of the present invention. [Figure 4] FIG. 2 is a schematic cross-sectional view showing still another example of the configuration of the sheet for forming a protective film according to one embodiment of the present invention. [Figure 5] 1 is a schematic cross-sectional view showing an example of a semiconductor wafer having a plurality of bumps. [Figure 6] FIG. 10 is a schematic cross-sectional view showing another example of a semiconductor wafer having a plurality of bumps. [Figure 7] FIG. 1 is a top view of three enlarged bumps on a semiconductor wafer to define the bump pitch (BMP) and bump width (BMw). [Figure 8] 3 is a schematic cross-sectional view illustrating step (S2) of the method for producing a semiconductor wafer with a protective film according to one embodiment of the present invention. FIG. [Figure 9]3 is a schematic cross-sectional view illustrating step (S3) of the method for producing a semiconductor wafer with a protective film according to one embodiment of the present invention. FIG. [Figure 10] 3 is a schematic cross-sectional view illustrating step (U2) of the semiconductor package manufacturing method according to one embodiment of the present invention. FIG. [Figure 11] FIG. 1 is a schematic cross-sectional view showing the relationship between the bump height (BMh) and the thickness (XT) (unit: μm) at 23° C. of a protective film (X) formed by curing a curable resin film (x). DETAILED DESCRIPTION OF THE INVENTION

[0011] In this specification, the term "active ingredient" refers to the components contained in the target composition, excluding diluent solvents such as water and organic solvents. In addition, in this specification, "(meth)acrylic acid" refers to both "acrylic acid" and "methacrylic acid", and the same applies to other similar terms. In this specification, the weight average molecular weight and number average molecular weight are values measured by gel permeation chromatography (GPC) in terms of polystyrene. Furthermore, in this specification, for preferred numerical ranges (e.g., ranges of content, etc.), the lower and upper limits described in stages can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to form "10 to 60."

[0012] [Embodiments of the protective film-forming sheet] The sheet for forming a protective film of the present invention has a laminated structure of a curable resin film (x) and a support sheet (Y). The sheet for forming a protective film of the present invention is used to form a protective film (X) on the bump-forming surface of a semiconductor wafer that has a plurality of bumps and satisfies the following requirements (α1) to (α2). Requirement (α1): The width of the bump (BM w ) (unit: μm) is 20 μm to 350 μm. Requirement (α2): The pitch of the bumps (BM P ) (unit: μm) and the width of the bump (BM w ) (unit: μm) satisfies the following formula (I). [(BM P ) / (BM w )]≦1.0 (I) The sheet for forming a protective film of the present invention satisfies the following requirements (β1) to (β3). Requirement (β1): The protective film (X) formed by curing the curable resin film (x) has a tensile modulus E' (23°C) at 23°C of 1 x 10 7 Pa~1×10 10 It is Pa. Requirement (β2): The protective film (X) formed by curing the curable resin film (x) has a tensile modulus E' (260°C) at 260°C of 1×10 5 Pa~1×10 8 It is Pa. Requirement (β3): The thickness (X) of the protective film (X) formed by curing the curable resin film (x) at 23°C T ) (unit: μm) and the height of the bump (BM h ) (unit: μm) satisfies the following formula (II). [(X T ) / (BM h )] ≥ 0.2 (II)

[0013] That is, the sheet for forming a protective film of the present invention is used on the bump formation surface of a semiconductor wafer having bumps with narrow pitches, which satisfies the above requirements (α1) to (α2).The sheet for forming a protective film of the present invention has, as a specific configuration, a laminated structure of a curable resin film (x) and a support sheet (Y), and satisfies the above requirements (β1) to (β3) related to the curable resin film (x).

[0014] The present inventors have found that by forming a protective film (X) on the bump-forming surface of a semiconductor wafer having narrow-pitched bumps that satisfy the above requirements (α1) to (α2) using a sheet for forming a protective film, which has a laminated structure of a curable resin film (x) and a support sheet (Y) and satisfies the above requirements (β1) to (β3) related to the curable resin film (x), it is possible to suppress crushing and deformation of the bumps and to suppress short circuits between the narrow-pitched bumps. The above requirements (β1) to (β3) related to the protective film (X) defined in the sheet for forming a protective film of the present invention will be explained below.

[0015] <Requirements (β1)> The requirement (β1) is that the tensile modulus E' (23°C) of the protective film (X) formed by curing the curable resin film (x) at 23°C is 1 × 10 7 Pa~1×10 10 It is stipulated that Pa. Tensile modulus E' (23°C) is 1 x 10 7 If it is less than Pa, the protective film (X) cannot prevent the bumps from being crushed and deformed, and the bumps may come into contact with each other and cause a short circuit. On the other hand, the tensile modulus E' (23°C) is 1 × 10 10 If it exceeds Pa, the stress during heating and cooling will be high, which will impose a load on the bumps and reduce their reliability. Here, in order to more easily suppress the crushing and deformation of the bumps and to reduce the load on the bumps during heating and cooling, the protective film (X) formed by curing the curable resin film (x) preferably has a tensile modulus E' (23°C) at 23°C of 3×10 7 Pa~8×10 9 Pa, more preferably 5×10 7 Pa ~ 7 × 10 9 Pa, more preferably 7×10 7 Pa~6×10 9 It is Pa. The protective film (X) having the tensile modulus E' (23°C) specified by requirement (β1) is formed by curing a curable resin film (x). The method for preparing the curable resin film (x) for forming the protective film (X) will be described later.

[0016] <Requirements (β2)> The requirement (β2) is that the tensile modulus E'(260°C) of the protective film (X) formed by curing the curable resin film (x) at 260°C is 1 × 10 5 Pa~1×10 8 It is stipulated that Pa. Tensile modulus E' (260°C) is 5 x 10 5 If it is less than Pa, the protective film (X) cannot suppress the crushing and deformation of the bumps, particularly in the heating temperature range (e.g., 250°C to 270°C) in the step of electrically bonding a wiring substrate and a semiconductor wafer having bumps via the bumps, and there is a risk that the bumps will come into contact with each other and cause a short circuit. On the other hand, the tensile modulus E' (260°C) is 5 × 10 7 If it exceeds Pa, the stress during heating and cooling will be high, which will impose a load on the bumps and reduce reliability and bonding properties. Here, in order to more easily suppress the crushing and deformation of the bumps and to reduce the load on the bumps during heating and cooling, the protective film (X) formed by curing the curable resin film (x) preferably has a tensile modulus E'(260°C) at 260°C of 7×10 5 Pa~3×10 7 Pa, more preferably 9×10 5 Pa~2×10 7 Pa, more preferably 1×10 6 Pa ~ 1.5 × 10 7 It is Pa. The protective film (X) having the tensile modulus E' (260°C) specified by requirement (β2) is formed by curing a curable resin film (x). The method for preparing the curable resin film (x) for forming the protective film (X) will be described later.

[0017] <Requirements (β3)> Requirement (β3) is the thickness (X) of the protective film (X) formed by curing the curable resin film (x) at 23°C. T ) (unit: μm) and the height of the bump (BM h ) (unit: μm). Specifically, the following formula (II) is satisfied. [(X T ) / (BM h )] ≥ 0.2 (II) [(X T ) / (BM h )]<0.2, the bump height (BM h ) is insufficient to cover the bumps, and the protective film (X) cannot prevent the bumps from being crushed or deformed, which may cause the bumps to come into contact with each other and short-circuit. In addition, [(X T ) / (BM h The upper limit of )] is not particularly limited, but is preferably 1.0 or less, more preferably less than 1.0, from the viewpoint of exposing the bump tops from the protective film (X). Here, from the viewpoint of making it easier to suppress the crushing and deformation of the bumps and from the viewpoint of exposing the tops of the bumps from the protective film (X), it is preferable that the requirement (β3) satisfies the following formula (IIa).

[0018] P≦[(X T ) / (BM h )]≦Q (IIa) In formula (IIa), P is 0.2, preferably 0.30, more preferably 0.40, and even more preferably 0.50. In addition, in formula (IIa), Q is preferably 1.0, more preferably 0.90, and even more preferably 0.80.

[0019] The thickness of the curable resin film (x) that satisfies the relationship specified in requirement (β3) can be adjusted based on the relationship between the thickness of the curable resin film (x) and the thickness of the protective film (X) formed by curing the curable resin film (x), and information such as the height of the bumps on the semiconductor wafer to be used. Figure 11 shows the bump height (BM h) and the thickness (X) at 23°C of the protective film (X) formed by curing the curable resin film (x). T ) (unit: μm). The thickness (X) of the protective film (X) formed by curing the curable resin film (x) at 23°C T ) (unit: μm) is the bump height (BM h ) is measured, the height from the bump forming surface 41a to the position 50 at the contact point between the bump and the protective film (X) that is the farthest from the bump forming surface 41a. However, the position 50 farthest from the bump-forming surface 41a is determined within the region where the protective film (X) formed on the bump-forming surface 41a is continuously present. Therefore, for example, the position 50 farthest from the bump-forming surface 41a is not determined from the contact portion between the protective film (X) and the bump, which is partially present on the top of the bump and is removed by the exposure treatment (plasma etching treatment) described below. Furthermore, when the exposure treatment (plasma etching treatment) described below is performed, the thickness of the protective film (X) after the receding due to the exposure treatment must satisfy the above formula (II) (0.2 μm or more). In other words, regardless of whether the exposure treatment described below is performed or not, the thickness of the protective film (X) must naturally satisfy the above formula (II) (0.2 μm or more) immediately before the process of electrically connecting the semiconductor chip and the wiring board via the ball bumps. Bump height (BM h ) and the thickness of the protective film (X) T ) can be measured, for example, by cutting a semiconductor wafer with a protective film (X) in a direction perpendicular to the bump-forming surface and passing through the center of the bump, and observing the cut cross section with an optical microscope.

[0020] The sheet for forming a protective film of the present invention will be described in detail below, taking into consideration the method for preparing the curable resin film (x) for forming the protective film (X) that satisfies the requirements (β1) and (β2).

[0021] <<Configuration of the protective film forming sheet>> An example of the configuration of the sheet for forming a protective film of the present invention is shown in FIG. A sheet for forming a protective film according to one embodiment of the present invention has a curable resin film (x) provided on one surface of a support sheet (Y), as in the sheet for forming a protective film 1 shown in Fig. 1. By providing the curable resin film (x) on one surface of the support sheet (Y), the curable resin film (x) is stably supported and protected when transporting the curable resin film (x) as a product package or when conveying the curable resin film (x) in a process.

[0022] 2 to 4 show examples of the configuration of the sheet for forming a protective film according to one embodiment of the present invention. In one embodiment of the sheet for forming a protective film of the present invention, as shown in the sheet for forming a protective film 1a in FIG. 2, the support sheet (Y) is a substrate 11, and a curable resin film (x) is provided on one side of the substrate 11. Furthermore, in one embodiment of the sheet for forming a protective film of the present invention, as in the sheet for forming a protective film 1b shown in Figure 3, the support sheet (Y) may be an adhesive sheet formed by laminating a substrate 11 and an adhesive layer 21, and the adhesive layer 21 of the adhesive sheet may be bonded to the curable resin film (x). Furthermore, in one embodiment of the protective film formation sheet of the present invention, as in the protective film formation sheet 1c shown in FIG. 4, the support sheet (Y) may be an adhesive sheet formed by laminating a substrate 11, an intermediate layer 31, and an adhesive layer 21 in this order, and the adhesive layer 21 of the adhesive sheet may be bonded to a curable resin film (x). An adhesive sheet formed by laminating a substrate 11, an intermediate layer 31, and an adhesive layer 21 in this order can be suitably used as a backgrinding tape. That is, since the protective film formation sheet 1c shown in FIG. 4 has a backgrinding tape as the support sheet (Y), it can be suitably used when laminating the curable resin film (x) of the protective film formation sheet 1c to the bump-formed surface of a semiconductor wafer having a plurality of bumps, and then grinding the surface of the semiconductor wafer opposite the bump-formed surface (hereinafter also referred to as the "back surface of the semiconductor wafer") to thin the semiconductor wafer.

[0023] The curable resin film (x) and the support sheet (Y) used in the sheet for forming a protective film of the present invention will be described below.

[0024] <<Curable resin film (x)>> The curable resin film (x) is a film for protecting the bump-forming surface of a semiconductor wafer having a plurality of bumps, and forms a protective film (X) by curing through heating or energy ray irradiation. That is, the curable resin film (x) may be a thermosetting resin film (x1) that is cured by heating, or an energy ray-curable resin film (x2) that is cured by energy ray irradiation. In this specification, the term "energy rays" refers to electromagnetic waves or charged particle beams that have an energy quantum. Examples of such beams include ultraviolet rays and electron beams, with ultraviolet rays being preferred.

[0025] The physical properties of the curable resin film (x) can be adjusted by adjusting either or both of the types and amounts of the components contained in the curable resin film (x).

[0026] The thermosetting resin film (x1) and the energy ray-curable resin film (x2) will be described below.

[0027] <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). The polymer component (A) is a component that can be considered to be formed by a polymerization reaction of a polymerizable compound. The thermosetting component (B) is a component that can undergo a curing (polymerization) reaction when triggered by heat. The curing (polymerization) reaction also includes a polycondensation reaction. In the following description of this specification, "the content of each component in the total amount of active ingredients of the thermosetting resin composition (x1-1)" is synonymous with "the content of each component of the thermosetting resin film (x1) formed from the thermosetting resin composition (x1-1)."

[0028] (Polymer component (A)) The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) contain a polymer component (A). The polymer component (A) is a polymer compound for imparting film-forming properties, flexibility, etc. to the thermosetting resin film (x1). The polymer component (A) may be used alone or in combination of two or more. When two or more polymer components (A) are used in combination, the combination and ratio thereof can be selected arbitrarily.

[0029] Examples of the polymer component (A) include polyvinyl acetal, acrylic resins (resins having (meth)acryloyl groups), 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. These may be used alone or in combination of two or more. Among these, one or more selected from polyvinyl acetal and acrylic resins are preferred. Hereinafter, the polymer component (A) will be described using polyvinyl acetal and acrylic resin as examples.

[0030] Polyvinyl acetal The polyvinyl acetal used as the polymer component (A) is not particularly limited, and for example, known polyvinyl acetals can be used. Among polyvinyl acetals, for example, polyvinyl formal and polyvinyl butyral are listed, with polyvinyl butyral being more preferred. As the polyvinyl butyral, those having structural units represented by the following formulas (i-1), (i-2), and (i-3) are preferred from the viewpoint of improving the adhesion between the bump-forming surface of the semiconductor wafer and the protective film (X).

[0031] [ka] In the above formulas (i-1), (i-2), and (i-3), p, q, and r represent the content (mol %) of each structural unit.

[0032] The weight-average molecular weight (Mw) of the polyvinyl acetal is preferably 5,000 to 200,000, more preferably 8,000 to 100,000, even more preferably 9,000 to 80,000, and even more preferably 10,000 to 50,000. When the weight-average molecular weight of the polyvinyl acetal is within this range, the adhesion between the bump-forming surface of the semiconductor wafer and the protective film (X) is easily improved. In addition, the effect of suppressing the protective film (X) from remaining on the top of the bump (the top of the bump and the area nearby) is further enhanced.

[0033] The proportion p of the butyral group structural unit represented by the above formula (i-1) (degree of butyralization) is preferably 40 to 90 mol %, more preferably 50 to 85 mol %, and even more preferably 60 to 76 mol %, based on all structural units of the polymer component (A).

[0034] The content q of the structural unit having an acetyl group represented by the above formula (i-2) is preferably 0.1 to 9 mol %, more preferably 0.5 to 8 mol %, and even more preferably 1 to 7 mol %, based on all structural units of the polymer component (A).

[0035] The content r of the structural unit having a hydroxyl group represented by the above formula (i-3) is preferably 10 to 60 mol %, more preferably 10 to 50 mol %, and even more preferably 20 to 40 mol %, based on all structural units of the polymer component (A).

[0036] The glass transition temperature (Tg) of the polyvinyl acetal is preferably 40 to 80° C., more preferably 50 to 70° C. When the Tg of the polyvinyl acetal is in this range, when the thermosetting resin film (x1) is attached to the bump-formed surface of a bumped wafer, the effect of suppressing the protective film (X) from remaining above the bumps is enhanced, and the hardness of the protective film formed by thermally curing the thermosetting resin layer can be made sufficient. In this specification, the glass transition temperature (Tg) of a polymer (resin) is a value measured by the method described in the examples below.

[0037] The content ratio of the above three types of structural units constituting the polyvinyl butyral may be adjusted as desired depending on the desired physical properties. Furthermore, the polyvinyl butyral may contain structural units other than the above three structural units, but the content of the above three structural units is preferably 80 to 100 mol %, more preferably 90 to 100 mol %, and even more preferably 100 mol %, based on the total amount of the polyvinyl butyral.

[0038] Acrylic resin Examples of the acrylic resin include known acrylic polymers. The weight average molecular weight (Mw) of the acrylic resin is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,500,000. When the weight-average molecular weight of the acrylic resin is equal to or greater than the above-mentioned lower limit, the shape stability (stability over time during storage) of the thermosetting resin film (x1) is easily improved. Also, when the weight-average molecular weight of the acrylic resin is equal to or less than the above-mentioned upper limit, the thermosetting resin film (x1) is easily able to conform to the uneven surface of the adherend, which makes it easier to suppress, for example, the generation of voids between the adherend and the thermosetting resin film (x1).

[0039] The glass transition temperature (Tg) of the acrylic resin is preferably from -60 to 70°C, more preferably from -30 to 50°C. When the glass transition temperature (Tg) of the acrylic resin is equal to or higher than the lower limit, the adhesive strength between the protective film (X) and the support sheet (Y) is suppressed, improving the releasability of the support sheet (Y). When the glass transition temperature (Tg) of the acrylic resin is equal to or lower than the upper limit, the adhesive strength between the thermosetting resin film (x1) and the protective film (X) and the adherend is improved.

[0040] 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.

[0041] Examples of the (meth)acrylic acid ester constituting the acrylic resin include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, and (meth) (meth)acrylic acid alkyl esters in which the alkyl group constituting the alkyl ester has a chain structure and has 1 to 18 carbon atoms, such as isononyl acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate (myristyl (meth)acrylate), pentadecyl (meth)acrylate, hexadecyl (meth)acrylate (palmityl (meth)acrylate), heptadecyl (meth)acrylate, and octadecyl (meth)acrylate (stearyl (meth)acrylate); (meth)acrylic acid cycloalkyl esters such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate; (Meth)acrylic acid aralkyl esters such as benzyl (meth)acrylate; (Meth)acrylic acid cycloalkenyl esters such as (meth)acrylic acid dicyclopentenyl ester; (Meth)acrylic acid cycloalkenyloxyalkyl esters such as (meth)acrylic acid dicyclopentenyloxyethyl ester; (Meth)acrylic acid imide; glycidyl group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate; hydroxyl group-containing (meth)acrylic acid esters such as hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; Examples include substituted amino group-containing (meth)acrylic acid esters such as N-methylaminoethyl (meth)acrylate. As used herein, the term "substituted amino group" refers to a group in which one or two hydrogen atoms of an amino group have been substituted with a group other than a hydrogen atom.

[0042] The acrylic resin may be, for example, a copolymer of one or more monomers selected from (meth)acrylic acid ester, (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, N-methylolacrylamide, and the like.

[0043] The monomer constituting the acrylic resin may be one type alone or two or more types. When the acrylic resin is composed of two or more types of monomers, the combination and ratio thereof can be selected arbitrarily.

[0044] The acrylic resin may have a functional group capable of bonding with other compounds, such as a vinyl group, a (meth)acryloyl group, an amino group, a hydroxyl group, a carboxyl group, or an isocyanate group. The functional group of the acrylic resin may be bonded to other compounds via a crosslinking agent (F) described below, or may be bonded directly to other compounds without the crosslinking agent (F). When the acrylic resin is bonded to other compounds via the functional group, the reliability of the package obtained using the thermosetting resin film (x1) tends to be improved.

[0045] Other resins In one embodiment of the present invention, a thermoplastic resin other than polyvinyl acetal and acrylic resin (hereinafter sometimes simply referred to as "thermoplastic resin") may be used as polymer component (A) alone without using an acrylic resin, or may be used in combination with polyvinyl acetal and / or an acrylic resin. The use of a thermoplastic resin may improve the peelability of the protective film (X) from the support sheet (Y), or may make it easier for the thermosetting resin film (x1) to conform to the uneven surface of the adherend, thereby further suppressing the occurrence of voids and the like between the adherend and the thermosetting resin film (x1).

[0046] The weight average molecular weight of the thermoplastic resin is preferably 1,000 to 100,000, and more preferably 3,000 to 80,000.

[0047] The glass transition temperature (Tg) of the thermoplastic resin is preferably from -30 to 150°C, more preferably from -20 to 120°C.

[0048] Examples of thermoplastic resins include polyester, polyurethane, phenoxy resin, polybutene, polybutadiene, and polystyrene.

[0049] The thermoplastic resin may be used alone or in combination of two or more kinds. When two or more kinds of thermoplastic resins are used, the combination and ratio thereof can be selected arbitrarily.

[0050] Polymer component (A) content From the viewpoint of facilitating the production of a protective film (X) that satisfies the requirements (β1) and (β2), the content of the polymer component (A) is preferably 5 to 85 mass%, more preferably 10 to 80 mass%, even more preferably 15 to 70 mass%, still more preferably 15 to 60 mass%, and even more preferably 15 to 50 mass%, based on the total amount of the active ingredients of the thermosetting resin composition (x1-1).

[0051] Preferred embodiments of polymer component (A) As described above, the polymer component (A) is preferably one or more selected from polyvinyl acetal and acrylic resin, but from the viewpoint of making it easier to obtain a protective film (X) that satisfies requirements (β1) and (β2), the polymer component (A) is preferably polyvinyl acetal. The polymer component (A) may also correspond to the thermosetting component (B). In the present invention, when the thermosetting resin composition (x1-1) contains components that correspond to both the polymer component (A) and the thermosetting component (B), the thermosetting resin composition (x1-1) is considered to contain both the polymer component (A) and the thermosetting component (B).

[0052] (Thermosetting component (B)) The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) contain a thermosetting component (B). The thermosetting component (B) is a component for curing the thermosetting resin film (x1) to form a hard protective film (X). The thermosetting component (B) may be used singly or in combination of two or more. When two or more thermosetting components (B) are used, the combination and ratio thereof can be selected arbitrarily.

[0053] Examples of the thermosetting component (B) include epoxy-based thermosetting resins, thermosetting polyimides, polyurethanes, unsaturated polyesters, silicone resins, etc. Among these, epoxy-based thermosetting resins are preferred.

[0054] The epoxy thermosetting resin is composed of an epoxy resin (B1) and a thermosetting agent (B2). The epoxy thermosetting resin may be used alone or in combination of two or more. When two or more epoxy thermosetting resins are used, the combination and ratio thereof can be selected arbitrarily.

[0055] Epoxy resin (B1) Examples of the epoxy resin (B1) include known epoxy resins, such as polyfunctional epoxy resins, biphenyl compounds, bisphenol A diglycidyl ether and its hydrogenated products, orthocresol novolac epoxy resins, dicyclopentadiene-type epoxy resins, biphenyl-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, phenylene skeleton-type epoxy resins, and bifunctional or higher epoxy compounds.

[0056] The epoxy resin (B1) may be an epoxy resin having an unsaturated hydrocarbon group. Epoxy resins having an unsaturated hydrocarbon group have higher compatibility with acrylic resins than epoxy resins without an unsaturated hydrocarbon group. Therefore, the use of an epoxy resin having an unsaturated hydrocarbon group improves the reliability of the package obtained using the thermosetting resin film (x1).

[0057] Examples of epoxy resins having unsaturated hydrocarbon groups include compounds obtained by converting some of the epoxy groups of a polyfunctional epoxy resin into groups having unsaturated hydrocarbon groups. Such compounds can be obtained, for example, by subjecting epoxy groups to an addition reaction with (meth)acrylic acid or a derivative thereof. Examples of epoxy resins having unsaturated hydrocarbon groups include compounds in which a group having an unsaturated hydrocarbon group is directly bonded to an aromatic ring or the like that constitutes the epoxy resin. The unsaturated hydrocarbon group is a polymerizable unsaturated group, and specific examples thereof include an ethenyl group (vinyl group), a 2-propenyl group (allyl group), a (meth)acryloyl group, and a (meth)acrylamide group. Among these, an acryloyl group is preferred.

[0058] The number average molecular weight of the epoxy resin (B1) is not particularly limited, but from the viewpoints of the curability of the thermosetting resin film (x1) and the strength and heat resistance of the protective film (X) after curing, it is preferably 300 to 30,000, more preferably 400 to 10,000, and even more preferably 500 to 3,000. The epoxy equivalent of the epoxy resin (B1) is preferably 100 to 1,000 g / eq, more preferably 300 to 800 g / eq.

[0059] The epoxy resin (B1) may be used alone or in combination of two or more. When two or more epoxy resins (B1) are used in combination, the combination and ratio thereof can be selected arbitrarily.

[0060] Heat hardener (B2) The heat curing agent (B2) functions as a curing agent for the epoxy resin (B1). The thermosetting agent (B2) may be, for example, a compound having two or more functional groups per molecule that can react with an epoxy group. Examples of the functional group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an anhydride group of an acid group. A phenolic hydroxyl group, an amino group, or an anhydride group of an acid group is preferred, and a phenolic hydroxyl group or an amino group is more preferred.

[0061] Among the heat curing agents (B2), examples of phenolic curing agents having a phenolic hydroxyl group include polyfunctional phenolic resins, biphenols, novolac-type phenolic resins, dicyclopentadiene-based phenolic resins, and aralkyl phenolic resins. Among the heat curing agents (B2), examples of amine-based curing agents having an amino group include dicyandiamide (hereinafter sometimes abbreviated as "DICY").

[0062] The heat curing agent (B2) may have an unsaturated hydrocarbon group. Examples of the thermosetting agent (B2) having an unsaturated hydrocarbon group include a compound in which some of the hydroxyl groups of a phenolic resin are substituted with a group having an unsaturated hydrocarbon group, or a compound in which a group having an unsaturated hydrocarbon group is directly bonded to an aromatic ring of a phenolic resin. The unsaturated hydrocarbon group in the thermosetting agent (B2) is the same as the unsaturated hydrocarbon group in the epoxy resin having an unsaturated hydrocarbon group described above.

[0063] When a phenol-based curing agent is used as the thermosetting agent (B2), it is preferable that the thermosetting agent (B2) has a high softening point or glass transition temperature, in order to facilitate improving the peelability of the protective film (X) from the support sheet (Y).

[0064] Of the thermosetting agents (B2), for example, the number average molecular weight of resin components such as polyfunctional phenol resins, novolac-type phenol resins, dicyclopentadiene-based phenol resins, and aralkyl phenol resins is preferably 300 to 30,000, more preferably 400 to 10,000, and even more preferably 500 to 3,000. Of the thermosetting agent (B2), the molecular weight of the non-resin component such as biphenol or dicyandiamide is not particularly limited, but is preferably 60 to 500, for example.

[0065] The heat curing agent (B2) may be used singly or in combination of two or more. When two or more types of heat curing agents (B2) are used, the combination and ratio thereof can be selected arbitrarily.

[0066] In the thermosetting resin composition (x1-1), the content of the thermosetting agent (B2) is preferably 0.1 to 500 parts by mass, and more preferably 1 to 200 parts by mass, per 100 parts by mass of the epoxy resin (B1). When the content of the thermosetting agent (B2) is equal to or greater than the above lower limit, the curing of the thermosetting resin film (x1) proceeds more easily. When the content of the thermosetting agent (B2) is equal to or less than the above 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.

[0067] In the thermosetting resin composition (x1-1), the content of the thermosetting component (B) (total content of the epoxy resin (B1) and the thermosetting agent (B2)) is preferably 50 to 1,000 parts by mass, more preferably 70 to 800 parts by mass, even more preferably 80 to 600 parts by mass, even more preferably 90 to 500 parts by mass, and even more preferably 100 to 400 parts by mass, relative to 100 parts by mass of the polymer component (A). When the content of the thermosetting component (B) is within this range, the adhesive strength between the protective film (X) and the support sheet (Y) is suppressed, improving the releasability of the support sheet (Y). Furthermore, it is easier to obtain a protective film (X) that satisfies the requirements (β1) and (β2). Note that the tensile modulus E' tends to increase as the amount of the thermosetting component (B) increases relative to the polymer component (A). Conversely, the tensile modulus E' tends to decrease as the amount of the thermosetting component (B) relative to the polymer component (A) decreases.

[0068] (Curing accelerator (C)) The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a curing accelerator (C). The curing accelerator (C) is a component for adjusting the curing rate of the thermosetting resin composition (x1-1). Preferred examples of the curing accelerator (C) include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles (imidazoles in which one or more hydrogen atoms are substituted with groups other than hydrogen atoms) such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole; organic phosphines (phosphines in which one or more hydrogen atoms are substituted with organic groups) such as tributylphosphine, diphenylphosphine, and triphenylphosphine; and tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate.

[0069] The curing accelerator (C) may be used singly or in combination of two or more. When two or more curing accelerators (C) are used, the combination and ratio thereof can be selected arbitrarily.

[0070] When a curing accelerator (C) is used in the thermosetting resin composition (x1-1), the content of the curing accelerator (C) is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the thermosetting component (B). When the content of the curing accelerator (C) is equal to or greater than the above-mentioned lower limit, the effect of using the curing accelerator (C) is more pronounced. Furthermore, when the content of the curing accelerator (C) is equal to or less than the above-mentioned upper limit, for example, the effect of suppressing the highly polar curing accelerator (C) from migrating and segregating to the adhesive interface with the adherend in the thermosetting resin film (x1) under high temperature and high humidity conditions is enhanced, thereby further improving the reliability of the package obtained using the thermosetting resin film (x1).

[0071] (Filling material (D)) The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a filler (D). The inclusion of the filler (D) makes it easier to adjust the thermal expansion coefficient of the protective film (X) obtained by curing the curable resin film (x1) to an appropriate range, thereby further improving the reliability of the package obtained using the thermosetting resin film (x1). Furthermore, the inclusion of the filler (D) in the thermosetting resin film (x1) can also reduce the moisture absorption rate of the protective film (X) and improve its heat dissipation properties.

[0072] The filler (D) may be either an organic filler or an inorganic filler, but is preferably an inorganic filler. Preferred inorganic fillers include, for example, powders of silica, alumina, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, boron nitride, etc.; beads obtained by spheronizing these inorganic fillers; surface-modified products of these inorganic fillers; single-crystal fibers of these inorganic fillers; glass fibers, etc. Among these, the inorganic filler is preferably silica or alumina.

[0073] The filler (D) may be used alone or in combination of two or more kinds. When two or more types of filler (D) are used, the combination and ratio thereof can be selected arbitrarily.

[0074] When the filler (D) is used, the content of the filler (D) is preferably 5 to 80 mass %, more preferably 7 to 60 mass %, based on the total amount of the active ingredients of the thermosetting resin composition (x1-1). When the content of the filler (D) is within this range, it becomes easier to adjust the thermal expansion coefficient.

[0075] The average particle diameter of the filler (D) is preferably 5 nm to 1,000 nm, more preferably 5 nm to 500 nm, and even more preferably 10 nm to 300 nm. The average particle diameter is determined by measuring the outer diameter of a single particle at several points and calculating the average value.

[0076] (Coupling agent (E)) The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a coupling agent (E). The use of a coupling agent (E) having a functional group capable of reacting with an inorganic or organic compound facilitates improving the adhesiveness and adhesion of the thermosetting resin film (x1) to an adherend. Furthermore, the use of the coupling agent (E) facilitates improving the water resistance of the protective film (X) obtained by curing the thermosetting resin film (x1) without impairing its heat resistance.

[0077] The coupling agent (E) is preferably a compound having a functional group capable of reacting with the functional groups of the polymer component (A) and the thermosetting component (B), and more preferably a silane coupling agent. Preferred silane coupling agents include, for example, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxymethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethylamino) ... Examples of suitable silanes include 3-(triethoxysilylpropyl)triethoxysilane, 3-(phenylamino)propyltrimethoxysilane, 3-(phenylamino)propyltrimethoxysilane, 3-anilinopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazole silane.

[0078] The coupling agent (E) may be used singly or in combination of two or more. When two or more coupling agents (E) are used, the combination and ratio thereof can be selected arbitrarily.

[0079] When a coupling agent (E) is used in the thermosetting resin composition (x1-1), the content of the coupling agent (E) is preferably 0.03 to 20 parts by mass, more preferably 0.05 to 10 parts by mass, and even more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the total content of the polymer component (A) and the thermosetting component (B). When the content of the coupling agent (E) is at or above the lower limit, the effects of using the coupling agent (E), such as improved dispersibility of the filler (D) in the resin and improved adhesion of the thermosetting resin film (x1) to the adherend, are more significantly obtained. Furthermore, when the content of the coupling agent (E) is at or below the upper limit, outgassing is further suppressed.

[0080] (Crosslinking agent (F)) When the polymer component (A), such as the above-mentioned acrylic resins, has a functional group capable of bonding to other compounds, such as a vinyl group, a (meth)acryloyl group, an amino group, a hydroxyl group, a carboxyl group, or an isocyanate group, the thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a crosslinking agent (F) for bonding the functional group to other compounds to form crosslinks. By crosslinking with the crosslinking agent (F), the initial adhesive strength and cohesive strength of the thermosetting resin film (x1) can be adjusted.

[0081] Examples of the crosslinking agent (F) include organic polyvalent isocyanate compounds, organic polyvalent imine compounds, metal chelate crosslinking agents (crosslinking agents having a metal chelate structure), and aziridine crosslinking agents (crosslinking agents having an aziridinyl group).

[0082] Examples of organic polyisocyanate compounds include aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, and alicyclic polyisocyanate compounds (hereinafter, these compounds may be collectively referred to as "aromatic polyisocyanate compounds, etc."); trimers, isocyanurates, and adducts of the aromatic polyisocyanate compounds, etc.; and isocyanate-terminated urethane prepolymers obtained by reacting the aromatic polyisocyanate compounds, etc. with polyol compounds. The "adduct" refers to a reaction product of the aromatic polyisocyanate compound, aliphatic polyisocyanate compound, or alicyclic polyisocyanate compound with a low-molecular-weight active hydrogen-containing compound such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, or castor oil, and examples thereof include the xylylene diisocyanate adduct of trimethylolpropane.

[0083] More specific examples of organic polyisocyanate compounds include 2,4-tolylene diisocyanate; 2,6-tolylene diisocyanate; 1,3-xylylene diisocyanate; 1,4-xylylene diisocyanate; diphenylmethane-4,4'-diisocyanate; diphenylmethane-2,4'-diisocyanate; 3-methyldiphenylmethane diisocyanate; hexamethylene diisocyanate; isophorone diisocyanate; dicyclohexylmethane-4,4'-diisocyanate; dicyclohexylmethane-2,4'-diisocyanate; compounds in which one or more of tolylene diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are added to all or some of the hydroxyl groups of a polyol such as trimethylolpropane; lysine diisocyanate, and the like.

[0084] Examples of the organic polyvalent imine compound include N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, and N,N'-toluene-2,4-bis(1-aziridinecarboxamide)triethylenemelamine.

[0085] When an organic polyisocyanate compound is used as the crosslinking agent (F), it is preferable to use a hydroxyl group-containing polymer as the polymer component (A). When the crosslinking agent (F) has an isocyanate group and the polymer component (A) has a hydroxyl group, a crosslinked structure can be easily introduced into the thermosetting resin film (x1) by the reaction between the crosslinking agent (F) and the polymer component (A).

[0086] The crosslinking agent (F) may be used singly or in combination of two or more. When two or more crosslinking agents (F) are used, the combination and ratio thereof can be selected arbitrarily.

[0087] When a crosslinking agent (F) is used in the thermosetting resin composition (x1-1), the content of the crosslinking agent (F) is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the polymer component (A). When the content of the crosslinking agent (F) is equal to or greater than the lower limit, the effect of using the crosslinking agent (F) is more pronounced. Furthermore, when the content of the crosslinking agent (F) is equal to or less than the upper limit, excessive use of the crosslinking agent (F) is suppressed.

[0088] (Energy ray curable resin (G)) The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain an energy ray-curable resin (G). The thermosetting resin film (x1) contains the energy ray curable resin (G), and thus the properties can be changed by irradiation with energy rays.

[0089] The energy ray curable resin (G) is obtained by polymerizing (curing) an energy ray curable compound. Examples of the energy ray curable compound include compounds having at least one polymerizable double bond in the molecule, and acrylate compounds having a (meth)acryloyl group are preferred.

[0090] Examples of acrylate compounds include chain acrylates such as trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate. Examples of the (meth)acrylate include aliphatic skeleton-containing (meth)acrylates; alicyclic skeleton-containing (meth)acrylates such as dicyclopentanyl di(meth)acrylate; polyalkylene glycol (meth)acrylates such as polyethylene glycol di(meth)acrylate; oligoester (meth)acrylates; urethane (meth)acrylate oligomers; epoxy-modified (meth)acrylates; polyether (meth)acrylates other than the above-mentioned polyalkylene glycol (meth)acrylates; and itaconic acid oligomers.

[0091] The weight average molecular weight of the energy ray-curable compound is preferably from 100 to 30,000, and more preferably from 300 to 10,000.

[0092] The energy ray-curable compound used for polymerization may be used alone or in combination of two or more. When two or more energy ray-curable compounds are used for polymerization, the combination and ratio thereof can be selected arbitrarily.

[0093] When the energy ray-curable resin (G) is used, the content of the energy ray-curable resin (G) is preferably 1 to 95 mass%, more preferably 5 to 90 mass%, and even more preferably 10 to 85 mass%, based on the total amount of the active ingredients of the thermosetting resin composition (x1-1).

[0094] (Photopolymerization initiator (H)) When the thermosetting resin film (x1) and the thermosetting resin composition (x1-1) contain an energy ray-curable resin (G), the thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a photopolymerization initiator (H) in order to efficiently proceed with the polymerization reaction of the energy ray-curable resin (G).

[0095] Examples of the photopolymerization initiator (H) 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.

[0096] The photopolymerization initiator (H) may be used singly or in combination of two or more. When two or more photopolymerization initiators (H) are used, the combination and ratio thereof can be selected arbitrarily.

[0097] In the thermosetting resin composition (x1-1), the content of the photopolymerization initiator (H) is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass, and even more preferably 2 to 5 parts by mass, relative to 100 parts by mass of the content of the energy ray-curable resin (G).

[0098] (General-purpose additives (I)) The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a general-purpose additive (I) within the range that does not impair the effects of the present invention. The general-purpose additive (I) may be a known additive and may be selected arbitrarily depending on the purpose, and is not particularly limited. Preferable general-purpose additives (I) include, for example, plasticizers, antistatic agents, antioxidants, colorants (dyes, pigments), gettering agents, and the like.

[0099] The general-purpose additive (I) may be used singly or in combination of two or more. When two or more general-purpose additives (I) are used, the combination and ratio thereof can be selected arbitrarily. The content of the general-purpose additive (I) is not particularly limited and may be appropriately selected depending on the purpose.

[0100] (solvent) The thermosetting resin composition (x1-1) preferably further contains a solvent. The thermosetting resin composition (x1-1) containing a solvent has good handleability. The solvent is not particularly limited, but preferred examples include hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, 2-propanol, isobutyl alcohol (2-methylpropan-1-ol), and 1-butanol; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; and amides (compounds having an amide bond) such as dimethylformamide and N-methylpyrrolidone. The solvent may be used alone or in combination of two or more. When two or more solvents are used, the combination and ratio thereof can be selected arbitrarily. The solvent is preferably methyl ethyl ketone or the like, since it allows the components contained in the thermosetting resin composition (x1-1) to be mixed more uniformly.

[0101] (Method for preparing thermosetting resin composition (x1-1)) The thermosetting resin composition (x1-1) is prepared by blending the components that constitute it. The order of addition of the components when blending is not particularly limited, and two or more components may be added simultaneously. When a solvent is used, the solvent may be mixed with any of the other components to pre-dilute the components, or the solvent may be mixed with any of the other components without pre-diluting them. The method for mixing the components during blending is not particularly limited, and may be appropriately selected from known methods such as a method of mixing by rotating a stirrer or stirring blades, a method of mixing using a mixer, or a method of mixing by adding ultrasound. The temperature and time for adding and mixing each component are not particularly limited as long as the components do not deteriorate, and may be adjusted appropriately. A temperature of 15 to 30°C is preferred.

[0102] <Energy ray curable resin film (x2)> The energy ray-curable resin film (x2) contains an energy ray-curable component (a). The energy ray-curable resin film (x2) is formed, for example, from an energy ray-curable resin composition (x2-1) containing an energy ray-curable component (a). The energy ray-curable component (a) is preferably uncured and has adhesive properties, and more preferably uncured and has adhesive properties. In the following description of this specification, "the content of each component based on the total amount of active ingredients of the energy ray-curable resin composition (x2-1)" is synonymous with "the content of each component of the energy ray-curable resin film (x2) formed from the energy ray-curable resin composition (x2-1)."

[0103] (Energy ray-curable component (a)) The energy ray-curable component (a) is a component that is cured by irradiation with energy rays, and is also a component that imparts film-forming properties, flexibility, and the like to the energy ray-curable resin film (x2). Examples of the energy ray-curable component (a) include a polymer (a1) having an energy ray-curable group and a weight-average molecular weight of 80,000 to 2,000,000, and a compound (a2) having an energy ray-curable group and a molecular weight of 100 to 80,000. The polymer (a1) may be at least partially crosslinked with a crosslinking agent, or may not be crosslinked.

[0104] (Polymer (a1)) Examples of the polymer (a1) having an energy ray-curable group and a weight average molecular weight of 80,000 to 2,000,000 include an acrylic resin (a1-1) obtained by polymerizing an acrylic polymer (a11) having a functional group capable of reacting with a group possessed by another compound, and an energy ray-curable compound (a12) having a group reactive with the functional group and an energy ray-curable group such as an energy ray-curable double bond.

[0105] Examples of functional groups that can react with groups possessed by other compounds include hydroxyl groups, carboxyl groups, amino groups, substituted amino groups (groups in which one or two hydrogen atoms of an amino group are substituted with groups other than hydrogen atoms), and epoxy groups. However, from the viewpoint of preventing corrosion of circuits such as semiconductor wafers and semiconductor chips, it is preferable that the functional group be a group other than a carboxyl group. Among these, it is preferable that the functional group be a hydroxyl group.

[0106] Acrylic polymer having functional groups (a11) The acrylic polymer (a11) having a functional group may be, for example, a copolymer of an acrylic monomer having a functional group and an acrylic monomer not having a functional group, or may be a copolymer of these monomers with a monomer other than the acrylic monomer (non-acrylic monomer). The acrylic polymer (a11) may be a random copolymer or a block copolymer.

[0107] Examples of the acrylic monomer having a functional group include a hydroxyl group-containing monomer, a carboxy group-containing monomer, an amino group-containing monomer, a substituted amino group-containing monomer, and an epoxy group-containing monomer.

[0108] Examples of hydroxyl group-containing monomers include hydroxyalkyl (meth)acrylates such as hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; and non-(meth)acrylic unsaturated alcohols (unsaturated alcohols not having a (meth)acryloyl skeleton) such as vinyl alcohol and allyl alcohol.

[0109] Examples of carboxy group-containing monomers include ethylenically unsaturated monocarboxylic acids (monocarboxylic acids having an ethylenically unsaturated bond) such as (meth)acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids (dicarboxylic acids having an ethylenically unsaturated bond) such as fumaric acid, itaconic acid, maleic acid and citraconic acid; anhydrides of the above ethylenically unsaturated dicarboxylic acids; and (meth)acrylic acid carboxyalkyl esters such as 2-carboxyethyl methacrylate.

[0110] The acrylic monomer having a functional group is preferably a hydroxyl group-containing monomer or a carboxyl group-containing monomer, and more preferably a hydroxyl group-containing monomer.

[0111] The acrylic monomer having a functional group that constitutes the acrylic polymer (a11) may be used alone or in combination of two or more. When the acrylic polymer (a11) contains two or more types of acrylic monomers having a functional group, the combination and ratio thereof can be selected arbitrarily.

[0112] Examples of acrylic monomers having no functional group include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, and isopropyl (meth)acrylate. Examples of (meth)acrylic acid alkyl esters include those in which the alkyl group constituting the alkyl ester has a chain structure and has 1 to 18 carbon atoms, such as nonyl, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate (myristyl (meth)acrylate), pentadecyl (meth)acrylate, hexadecyl (meth)acrylate (palmityl (meth)acrylate), heptadecyl (meth)acrylate, and octadecyl (meth)acrylate (stearyl (meth)acrylate).

[0113] Examples of acrylic monomers having no functional group include (meth)acrylic acid esters having an alkoxyalkyl group, such as methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and ethoxyethyl (meth)acrylate; (meth)acrylic acid esters having an aromatic group, including (meth)acrylic acid aryl esters, such as phenyl (meth)acrylate; non-crosslinkable (meth)acrylamide and derivatives thereof; and (meth)acrylic acid esters having a non-crosslinkable tertiary amino group, such as N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate.

[0114] The acrylic monomer having no functional group that constitutes the acrylic polymer (a11) may be used alone or in combination of two or more. When the acrylic polymer (a11) contains two or more types of acrylic monomers having no functional group, the combination and ratio thereof can be selected arbitrarily.

[0115] Examples of non-acrylic monomers include olefins such as ethylene and norbornene; vinyl acetate; and styrene.

[0116] The non-acrylic monomer constituting the acrylic polymer (a11) may be used singly or in combination of two or more. When the acrylic polymer (a11) is composed of two or more non-acrylic monomers, the combination and ratio thereof can be selected arbitrarily.

[0117] In the acrylic polymer (a11), the proportion (content) of the amount of structural units derived from an acrylic monomer having a functional group relative to the total mass of the structural units constituting the acrylic polymer (a11) is preferably 0.1 to 50 mass%, more preferably 1 to 40 mass%, and even more preferably 3 to 30 mass%. When the proportion is within this range, the content of the energy ray-curable group in the acrylic resin (a1-1) obtained by copolymerization of the acrylic polymer (a11) and the energy ray-curable compound (a12) makes it possible to easily adjust the degree of curing of the protective film (X) within a preferred range.

[0118] The acrylic polymer (a11) constituting the acrylic resin (a1-1) may be used singly or in combination of two or more. When the acrylic polymer (a11) constituting the acrylic resin (a1-1) is two or more types, the combination and ratio thereof can be selected arbitrarily.

[0119] The content of the acrylic resin (a1-1) is preferably 1 to 60 mass %, more preferably 3 to 50 mass %, and even more preferably 5 to 40 mass %, based on the total amount of active ingredients of the energy ray-curable resin composition (x2-1).

[0120] Energy ray curable compounds (a12) The energy ray-curable compound (a12) preferably has one or more groups selected from the group consisting of an isocyanate group, an epoxy group, and a carboxy group as a group reactive with the functional group of the acrylic polymer (a11), and more preferably has an isocyanate group as the group. When the energy ray-curable compound (a12) has, for example, an isocyanate group as the group, this isocyanate group readily reacts with the hydroxyl group of the acrylic polymer (a11) having a hydroxyl group as the functional group.

[0121] The energy ray-curable compound (a12) preferably has 1 to 5 energy ray-curable groups, and more preferably 1 or 2 energy ray-curable groups in one molecule.

[0122] Examples of the energy ray-curable compound (a12) include 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate; an acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate; and an acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with a polyol compound and hydroxyethyl (meth)acrylate. Among these, the energy ray-curable compound (a12) is preferably 2-methacryloyloxyethyl isocyanate.

[0123] The energy ray-curable compound (a12) constituting the acrylic resin (a1-1) may be used alone or in combination of two or more. When the energy ray-curable compound (a12) constituting the acrylic resin (a1-1) is two or more types, the combination and ratio thereof can be selected arbitrarily.

[0124] In the acrylic resin (a1-1), the ratio of the content of the energy ray-curable groups derived from the energy ray-curable compound (a12) to the content of the functional groups derived from the acrylic polymer (a11) is preferably 20 to 120 mol%, more preferably 35 to 100 mol%, and even more preferably 50 to 100 mol%. When the content is within this range, the adhesive strength of the protective film (X) after curing is increased. When the energy ray-curable compound (a12) is a monofunctional compound (having one such group per molecule), the upper limit of the content is 100 mol%. However, when the energy ray-curable compound (a12) is a polyfunctional compound (having two or more such groups per molecule), the upper limit of the content may exceed 100 mol%.

[0125] The weight average molecular weight (Mw) of the polymer (a1) is preferably from 100,000 to 2,000,000, and more preferably from 300,000 to 1,500,000.

[0126] When the polymer (a1) is at least partially crosslinked with a crosslinking agent, the polymer (a1) may be one which is obtained by polymerizing a monomer which does not correspond to any of the above-mentioned monomers described as constituting the acrylic polymer (a11) and has a group which reacts with the crosslinking agent, and which is crosslinked at the group which reacts with the crosslinking agent, or may be one which is derived from the energy ray-curable compound (a12) and which is crosslinked at a group which reacts with the functional group.

[0127] The polymer (a1) may be used singly or in combination of two or more. When two or more types of polymer (a1) are used, the combination and ratio thereof can be selected arbitrarily.

[0128] (Compound (a2)) The energy ray-curable group contained in the compound (a2) having an energy ray-curable group and a weight average molecular weight of 100 to 80,000 includes a group containing an energy ray-curable double bond, and preferred examples thereof include a (meth)acryloyl group or a vinyl group.

[0129] The compound (a2) is not particularly limited as long as it satisfies the above conditions, and examples thereof include a low-molecular-weight compound having an energy ray-curable group, an epoxy resin having an energy ray-curable group, and a phenolic resin having an energy ray-curable group.

[0130] Among the compounds (a2), examples of low molecular weight compounds having an energy ray-curable group include polyfunctional monomers or oligomers, and acrylate compounds having a (meth)acryloyl group are preferred. Examples of the acrylate compounds include 2-hydroxy-3-(meth)acryloyloxypropyl methacrylate, polyethylene glycol di(meth)acrylate, propoxylated ethoxylated bisphenol A di(meth)acrylate, 2,2-bis[4-((meth)acryloxypolyethoxy)phenyl]propane, ethoxylated bisphenol A di(meth)acrylate, 2,2-bis[4-((meth)acryloxydiethoxy)phenyl]propane, 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene, 2,2-bis[4-((meth)acryloxypolypropoxy)phenyl]propane, tricyclodecane dimethanol di(meth)acrylate, 1,10-decanediol ... bifunctional (meth)acrylates such as 6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 2,2-bis[4-((meth)acryloxyethoxy)phenyl]propane, neopentyl glycol di(meth)acrylate, ethoxylated polypropylene glycol di(meth)acrylate, and 2-hydroxy-1,3-di(meth)acryloxypropane;Examples of the polyfunctional (meth)acrylates include tris(2-(meth)acryloxyethyl)isocyanurate, ε-caprolactone-modified tris-(2-(meth)acryloxyethyl)isocyanurate, ethoxylated glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol poly(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; and polyfunctional (meth)acrylate oligomers such as urethane (meth)acrylate oligomers.

[0131] Of the compounds (a2), examples of epoxy resins having an energy ray-curable group and phenolic resins having an energy ray-curable group that can be used include those described in paragraph 0043 of JP 2013-194102 A.

[0132] The compound (a2) preferably has a weight average molecular weight of 100 to 30,000, more preferably 300 to 10,000.

[0133] The compound (a2) may be used singly or in combination of two or more. When two or more compounds (a2) are used, the combination and ratio thereof can be selected arbitrarily.

[0134] (Polymer (b) having no energy ray-curable group) When the energy ray-curable resin composition (x2-1) and the energy ray-curable resin film (x2) contain the compound (a2) as the energy ray-curable component (a), they preferably further contain a polymer (b) that does not have an energy ray-curable group. The polymer (b) having no energy ray-curable group may be at least partially crosslinked with a crosslinking agent, or may not be crosslinked.

[0135] Examples of the polymer (b) having no energy ray-curable group include acrylic polymers, phenoxy resins, urethane resins, polyesters, rubber-based resins, and acrylic urethane resins. Among these, the polymer (b) is preferably an acrylic polymer (hereinafter sometimes abbreviated as "acrylic polymer (b-1)").

[0136] The acrylic polymer (b-1) may be a known polymer, for example, a homopolymer of one acrylic monomer, or a copolymer of two or more acrylic monomers. Alternatively, the acrylic polymer (b-1) may be a copolymer of one or more acrylic monomers and one or more monomers other than the acrylic monomers (non-acrylic monomers).

[0137] Examples of the acrylic monomer constituting the acrylic polymer (b-1) include (meth)acrylic acid alkyl esters, (meth)acrylic acid esters having a cyclic skeleton, glycidyl group-containing (meth)acrylic acid esters, hydroxyl group-containing (meth)acrylic acid esters, and substituted amino group-containing (meth)acrylic acid esters.

[0138] Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, and isononyl (meth)acrylate. Examples of the alkyl (meth)acrylate include alkyl (meth)acrylates in which the alkyl group constituting the alkyl ester has a chain structure and has 1 to 18 carbon atoms, such as ethyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate (myristyl (meth)acrylate), pentadecyl (meth)acrylate, hexadecyl (meth)acrylate (palmityl (meth)acrylate), heptadecyl (meth)acrylate, and octadecyl (meth)acrylate (stearyl (meth)acrylate).

[0139] Examples of (meth)acrylic acid esters having a cyclic skeleton include (meth)acrylic acid cycloalkyl esters such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate; (meth)acrylic acid aralkyl esters such as benzyl (meth)acrylate; (meth)acrylic acid cycloalkenyl esters such as dicyclopentenyl (meth)acrylate; and (meth)acrylic acid cycloalkenyloxyalkyl esters such as dicyclopentenyloxyethyl (meth)acrylate.

[0140] Examples of the glycidyl group-containing (meth)acrylic acid ester include glycidyl (meth)acrylate, etc. Examples of the hydroxyl group-containing (meth)acrylic acid ester include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Examples of the substituted amino group-containing (meth)acrylic acid ester include N-methylaminoethyl (meth)acrylate.

[0141] Examples of non-acrylic monomers that constitute the acrylic polymer (b-1) include olefins such as ethylene and norbornene; vinyl acetate; and styrene.

[0142] The polymer (b) having no energy ray-curable group and at least a portion of which is crosslinked with a crosslinking agent may be, for example, a polymer in which a reactive functional group in the polymer (b) has reacted with a crosslinking agent. The reactive functional group is not particularly limited and may be appropriately selected depending on the type of crosslinking agent, etc. For example, when the crosslinking agent is a polyisocyanate compound, examples of the reactive functional group include a hydroxyl group, a carboxyl group, and an amino group, and among these, a hydroxyl group is preferred because of its high reactivity with an isocyanate group. When the crosslinking agent is an epoxy compound, examples of the reactive functional group include a carboxy group, an amino group, and an amide group, and among these, a carboxy group is preferred because it has high reactivity with an epoxy group. However, from the viewpoint of preventing corrosion of the circuits of semiconductor wafers and semiconductor chips, it is preferable that the reactive functional group is a group other than a carboxy group.

[0143] Examples of the polymer (b) having a reactive functional group but not having an energy ray-curable group include those obtained by polymerizing at least a monomer having a reactive functional group. In the case of the acrylic polymer (b-1), any one or both of the acrylic monomers and non-acrylic monomers listed as the constituent monomers may be used that have a reactive functional group. For example, examples of the polymer (b) having a hydroxyl group as a reactive functional group include those obtained by polymerizing a hydroxyl group-containing (meth)acrylic acid ester, and other examples include those obtained by polymerizing a monomer in which one or more hydrogen atoms in the acrylic monomer or non-acrylic monomer listed above are substituted with the reactive functional group.

[0144] In the polymer (b) having a reactive functional group, the proportion (content) of the amount of the structural units derived from the monomer having a reactive functional group relative to the total mass of the structural units constituting the polymer (b) is preferably 1 to 20 mass%, more preferably 2 to 10 mass%. When the proportion is in this range, the degree of crosslinking in the polymer (b) becomes a more preferable range.

[0145] The weight average molecular weight (Mw) of the polymer (b) having no energy ray-curable group is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,500,000, in order to improve the film-forming properties of the energy ray-curable resin composition (x2-1).

[0146] The polymer (b) having no energy ray-curable group may be used alone or in combination of two or more. When the polymer (b) having no energy ray-curable group is used in two or more types, the combination and ratio thereof can be selected arbitrarily.

[0147] The energy ray-curable resin composition (x2-1) may contain either or both of a polymer (a1) and a compound (a2). When the energy ray-curable resin composition (x2-1) contains the compound (a2), it preferably further contains a polymer (b) having no energy ray-curable group, and in this case, it is also preferable that it further contains a polymer (a1). Alternatively, the energy ray-curable resin composition (x2-1) may not contain the compound (a2) but may contain both the polymer (a1) and the polymer (b) having no energy ray-curable group.

[0148] When the energy ray-curable resin composition (x2-1) contains the polymer (a1), the compound (a2), and the polymer (b) having no energy ray-curable group, the content of the compound (a2) is preferably 10 to 400 parts by mass, and more preferably 30 to 350 parts by mass, per 100 parts by mass of the total content of the polymer (a1) and the polymer (b) having no energy ray-curable group.

[0149] The total content of the energy ray-curable component (a) and the polymer (b) having no energy ray-curable group is preferably 5 to 90 mass%, more preferably 10 to 80 mass%, and even more preferably 20 to 70 mass%, based on the total amount of active ingredients of the energy ray-curable resin composition (x2-1). When the content of the energy ray-curable component is within this range, the energy ray curability of the energy ray-curable resin film (x2) becomes better.

[0150] The energy ray-curable resin composition (x2-1) may contain, in addition to the energy ray-curable component, one or more selected from the group consisting of a thermosetting component, a photopolymerization initiator, a filler, a coupling agent, a crosslinking agent, and a general-purpose additive, depending on the purpose. For example, by using an energy ray-curable resin composition (x2-1) containing an energy ray-curable component and a thermosetting component, the adhesive strength of the formed energy ray-curable resin film (x2) to an adherend is improved by heating, and the strength of the protective film (X) formed from this energy ray-curable resin film (x2) is also improved.

[0151] The thermosetting component, photopolymerization initiator, filler, coupling agent, crosslinking agent, and general-purpose additives in the energy ray-curable resin composition (x2-1) may be the same as the thermosetting component (B), photopolymerization initiator (H), filler (D), coupling agent (E), crosslinking agent (F), and general-purpose additive (I) in the energy ray-curable resin composition (x2-1), respectively.

[0152] In the energy ray-curable resin composition (x2-1), the thermosetting component, photopolymerization initiator, filler, coupling agent, crosslinking agent, and general-purpose additive may each be used alone or in combination of two or more. When two or more are used in combination, the combination and ratio thereof can be selected arbitrarily. The contents of the thermosetting component, photopolymerization initiator, filler, coupling agent, crosslinking agent, and general-purpose additive in the energy ray-curable resin composition (x2-1) may be adjusted appropriately depending on the purpose, and are not particularly limited.

[0153] The energy ray-curable resin composition (x2-1) preferably further contains a solvent, since dilution improves its handleability. Examples of the solvent contained in the energy ray-curable resin composition (x2-1) include the same solvents as those in the thermosetting resin composition (x1-1). The solvent contained in the energy ray-curable resin composition (x2-1) may be used alone or in combination of two or more. When two or more types are used in combination, the combination and ratio thereof can be selected arbitrarily.

[0154] (Other ingredients) The energy ray-curable resin composition (x2-1) may contain, in addition to the above-described energy ray-curable component, appropriate amounts of components other than the curable component, such as a curing accelerator (C), a filler (D), a coupling agent (E), etc., as in the case of the thermosetting resin film (x1) described above.

[0155] (Method for producing energy ray-curable resin composition (x2-1)) The energy ray-curable resin composition (x2-1) can be obtained by blending the components that constitute it. The order in which the components are added when blended is not particularly limited, and two or more components may be added simultaneously. When a solvent is used, the solvent may be mixed with any of the other ingredients to dilute the ingredients before use, or the solvent may be mixed with any of the other ingredients without pre-diluting them. The method for mixing the ingredients during blending is not particularly limited, and may be appropriately selected from known methods such as a method of mixing by rotating a stirrer or stirring blades, a method of mixing using a mixer, or a method of mixing by applying ultrasound. The temperature and time for adding and mixing each component are not particularly limited as long as the components do not deteriorate, and may be adjusted appropriately. A temperature of 15 to 30°C is preferred.

[0156] <<Support sheet (Y)>> The support sheet (Y) functions as a support for supporting the curable resin film (x). The support sheet (Y) may be composed of only a substrate 11 as shown in Fig. 2, or may be a laminate of a substrate 11 and a pressure-sensitive adhesive layer 21 as shown in Fig. 3, or may be a laminate in which a substrate 11, an intermediate layer 31, and a pressure-sensitive adhesive layer 21 are laminated in this order as shown in Fig. 4. A laminate in which a substrate 11, an intermediate layer 31, and a pressure-sensitive adhesive layer 21 are laminated in this order is suitable for use as a backgrinding tape.

[0157] The substrate contained in the support sheet (Y), and the pressure-sensitive adhesive layer and intermediate layer that may be contained in the support sheet (Y) will be described below.

[0158] <Base material> The substrate is in the form of a sheet or film, and examples of the constituent materials thereof include the following various resins. Examples of resins constituting the substrate include polyethylenes such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE); polyolefins other than polyethylene such as polypropylene, polybutene, polybutadiene, polymethylpentene, and norbornene resin; ethylene-based copolymers (copolymers obtained using ethylene as a monomer) such as ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, and ethylene-norbornene copolymer; and vinyl chloride-based resins (copolymers obtained using vinyl chloride as a monomer) such as polyvinyl chloride and vinyl chloride copolymer. resins obtained by the above method); polystyrene; polycycloolefin; polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene isophthalate, polyethylene-2,6-naphthalenedicarboxylate, and wholly aromatic polyesters in which all structural units have aromatic cyclic groups; copolymers of two or more of the above polyesters; poly(meth)acrylic acid esters; polyurethanes; polyurethane acrylates; polyimides; polyamides; polycarbonates; fluororesins; polyacetals; modified polyphenylene oxides; polyphenylene sulfides; polysulfones; and polyether ketones. Further, examples of the resin constituting the substrate include polymer alloys such as mixtures of the polyester and other resins. The polymer alloys of the polyester and other resins preferably contain a relatively small amount of resin other than polyester. Further, examples of the resin constituting the substrate include crosslinked resins in which one or more of the resins exemplified above are crosslinked; and modified resins such as ionomers using one or more of the resins exemplified above.

[0159] The resin constituting the substrate may be one type used alone or two or more types used in combination. When the substrate is composed of two or more types of resins, the combination and ratio thereof can be selected arbitrarily.

[0160] The substrate may be one layer (single layer) or two or more layers. When the substrate is a multilayer substrate, these layers may be the same or different from each other, and the combination of these layers is not particularly limited.

[0161] The thickness of the substrate is preferably 5 μm to 1,000 μm, more preferably 10 μm to 500 μm, even more preferably 15 μm to 300 μm, and even more preferably 20 μm to 150 μm. Here, the "thickness of the substrate" means the thickness of the entire substrate, and for example, the thickness of a substrate consisting of multiple layers means the total thickness of all layers that make up the substrate.

[0162] The substrate preferably has a high thickness precision, i.e., a thickness variation that is suppressed regardless of location. Among the above-mentioned constituent materials, examples of materials with a high thickness precision that can be used to constitute the substrate include polyethylene, polyolefins other than polyethylene, polyethylene terephthalate, and ethylene-vinyl acetate copolymer.

[0163] In addition to the main constituent materials such as the resin, the substrate may contain various known additives such as fillers, colorants, antistatic agents, antioxidants, organic lubricants, catalysts, and softeners (plasticizers).

[0164] The substrate may be transparent or opaque, may be colored depending on the purpose, or may have other layers vapor-deposited thereon. When the curable resin film (x) is an energy ray-curable resin film (x2), and when the pressure-sensitive adhesive layer is an energy-curable pressure-sensitive adhesive layer, the substrate is preferably one that transmits energy rays.

[0165] The substrate can be produced by a known method. For example, a substrate containing a resin can be produced by molding a resin composition containing the resin.

[0166] <Adhesive layer> The pressure-sensitive adhesive layer is in the form of a sheet or film and contains a pressure-sensitive adhesive. Examples of adhesives include adhesive resins such as acrylic resins (adhesives made of resins having (meth)acryloyl groups), urethane resins (adhesives made of resins having urethane bonds), rubber resins (adhesives made of resins having a rubber structure), silicone resins (adhesives made of resins having siloxane bonds), epoxy resins (adhesives made of resins having epoxy groups), polyvinyl ethers, polycarbonates, etc. Among these, acrylic resins are preferred.

[0167] In the present invention, the term "adhesive resin" is a concept that includes both a resin having adhesive properties and a resin having adhesive properties, and includes, for example, not only resins that are adhesive in themselves, but also resins that become adhesive when used in combination with other components such as additives, and resins that become adhesive in the presence of a trigger such as heat or water.

[0168] The pressure-sensitive adhesive layer may be one layer (single layer) or two or more layers. When the pressure-sensitive adhesive layer is multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited.

[0169] The thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 1,000 μm, more preferably 5 μm to 500 μm, and even more preferably 10 μm to 100 μm. Here, the "thickness of the pressure-sensitive adhesive layer" refers to the thickness of the entire pressure-sensitive adhesive layer, and for example, the thickness of a pressure-sensitive adhesive layer consisting of multiple layers refers to the total thickness of all layers that make up the pressure-sensitive adhesive layer.

[0170] The pressure-sensitive adhesive layer may be formed using an energy ray-curable pressure-sensitive adhesive or a non-energy ray-curable pressure-sensitive adhesive. The pressure-sensitive adhesive layer formed using an energy ray-curable pressure-sensitive adhesive can easily adjust its physical properties before and after curing.

[0171] <Middle class> The intermediate layer is in the form of a sheet or film, and its constituent material may be appropriately selected depending on the purpose and is not particularly limited. For example, when the purpose is to prevent the protective film (X) covering the semiconductor surface from being deformed due to the shape of the bumps present on the semiconductor surface being reflected in the protective film, preferred constituent materials for the intermediate layer include urethane (meth)acrylate, etc., from the viewpoints of improving conformability to irregularities, improving bump penetration, and further improving the adhesion of the intermediate layer.

[0172] The intermediate layer may be one layer (single layer) or two or more layers. When the intermediate layer is a multi-layer structure, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited.

[0173] The thickness of the intermediate layer can be adjusted appropriately depending on the height of the bumps on the semiconductor surface to be protected, but is preferably 50 μm to 600 μm, more preferably 70 μm to 500 μm, and even more preferably 80 μm to 400 μm, so as to easily absorb the effects of relatively tall bumps. Here, the "thickness of the intermediate layer" refers to the thickness of the entire intermediate layer; for example, the thickness of an intermediate layer consisting of multiple layers refers to the total thickness of all the layers that make up the intermediate layer.

[0174] Next, a method for producing the sheet for forming a protective film will be described.

[0175] [Method of manufacturing the protective film-forming sheet] The protective film-forming sheet can be produced by laminating the above-mentioned layers in order so that they are in a corresponding positional relationship. For example, when manufacturing a support sheet, if a pressure-sensitive adhesive layer or an intermediate layer is laminated on a substrate, the pressure-sensitive adhesive composition or a composition for forming an intermediate layer can be applied to the substrate, and then dried or irradiated with energy rays as necessary, thereby laminating the pressure-sensitive adhesive layer or intermediate layer. Examples of the coating method include spin coating, spray coating, bar coating, knife coating, roll coating, roll knife coating, blade coating, die coating, and gravure coating.

[0176] On the other hand, for example, when a curable resin film (x) is laminated on a pressure-sensitive adhesive layer already laminated on a substrate, the curable resin film (x) can be directly formed by applying a thermosetting resin composition (x1-1) or an energy ray-curable resin composition (x2-1) on the pressure-sensitive adhesive layer. Similarly, when a pressure-sensitive adhesive layer is laminated on an intermediate layer already laminated on a substrate, the pressure-sensitive adhesive composition can be applied onto the intermediate layer to directly form the pressure-sensitive adhesive layer.

[0177] Thus, when forming a continuous two-layer laminate structure using any of the compositions, it is possible to form a new layer by applying another composition on the layer formed from the composition. However, it is preferable that the layer to be laminated later is first formed on a separate release film using the composition, and the exposed surface of this formed layer opposite the side in contact with the release film is bonded to the exposed surface of the remaining layer already formed to form a continuous two-layer laminate structure. In this case, it is preferable that the composition is applied to the release-treated surface of the release film. The release film can be removed as needed after the laminate structure is formed.

[0178] [Method for manufacturing a semiconductor wafer with a protective film using a protective film forming sheet] The method for producing a semiconductor wafer with a protective film of the present invention is carried out using the sheet for forming a protective film of the present invention described above. Specifically, the method includes the following steps (S1) to (S3). Step (S1): A step of preparing a semiconductor wafer having a bump-forming surface on which a plurality of bumps are provided. Step (S2): A step of adhering the sheet for forming a protective film of the present invention to the bump-forming surface of the semiconductor wafer while pressing the curable resin film (x) onto the bump-forming surface. Step (S3): A step of curing the curable resin film (x) to form a protective film (X). The method for producing a semiconductor wafer with a protective film of the present invention will be described below in detail with reference to the semiconductor wafer to which the method is applied.

[0179] <Process (S1)> In step (S1), a semiconductor wafer having a bump-forming surface on which a plurality of bumps are provided is prepared. An example of a semiconductor wafer having a bump-forming surface on which a plurality of bumps are provided, which is used in the method for manufacturing a semiconductor wafer with a protective film of the present invention, is shown in Fig. 5. A semiconductor wafer 40 having bumps has a plurality of bumps BM on a bump-forming surface (circuit surface) 41a of a semiconductor wafer 41. In the following description, a "semiconductor wafer having bumps" will also be referred to as a "bumped wafer." A "semiconductor wafer" will also be simply referred to as a "wafer."

[0180] The wafer 41 has circuits such as wiring, capacitors, diodes, and transistors formed on its surface. The material of the wafer is not particularly limited, and examples thereof include a silicon wafer, a silicon carbide wafer, a compound semiconductor wafer, a sapphire wafer, and a glass wafer.

[0181] The size of wafer 41 is not particularly limited, but from the viewpoint of improving batch processing efficiency, it is usually 8 inches (diameter 200 mm) or more, and preferably 12 inches (diameter 300 mm) or more. The shape of the wafer is not limited to a circle, and may be a polygonal shape such as a square or rectangle. In the case of a polygonal wafer, from the viewpoint of improving batch processing efficiency, it is preferable that the length of the longest side of wafer 41 is equal to or greater than the above size (diameter).

[0182] The thickness of the wafer 41 is not particularly limited, but from the viewpoint of easily suppressing warpage of the wafer 41 caused by curing the curable resin film (x), it is preferably 100 μm to 1,000 μm, more preferably 200 μm to 900 μm, and even more preferably 300 μm to 800 μm.

[0183] The shape of the bump BM is not particularly limited, and may be any shape as long as it can be brought into contact with and fixed to an electrode or the like on a chip-mounting substrate. For example, although the bump BM is shown as being ball-shaped in Fig. 5, the bump BM may also be a spheroid. The spheroid may be, for example, a spheroid stretched in a direction perpendicular to the bump-forming surface 41a of the wafer 41, or a spheroid stretched in a direction horizontal to the bump-forming surface 41a of the wafer 41. Moreover, the bump BM may be in the shape of a pillar, as shown in FIG. The bumps BM may be made of, for example, solder.

[0184] The present invention is applicable to semiconductor wafers having bumps with narrow pitches, as defined by the requirements described below. That is, in the present invention, a protective film (X) is formed on the bump formation surface of a semiconductor wafer having narrow-pitched bumps using a protective film forming sheet, thereby suppressing crushing and deformation of the narrow-pitched bumps and preventing short-circuiting between the bumps. In other words, the semiconductor wafer to which the present invention is applied is a semiconductor wafer having narrow-pitched bumps that, if the protective film (X) is not formed, may be short-circuited due to crushing or deformation of the bumps. The semiconductor wafer described below is a semiconductor wafer having narrow-pitch bumps that may be short-circuited due to crushing or deformation of the bumps if a protective film (X) is not formed.

[0185] <<Semiconductor wafers>> The sheet for forming a protective film of the present invention is used to form a protective film (X) on the bump-forming surface of a semiconductor wafer that satisfies the following requirements (α1) to (α2). The method for producing a semiconductor wafer with a protective film of the present invention is carried out using a semiconductor wafer that satisfies the following requirements (α1) to (α2). Requirement (α1): The width of the bump (BM w) (unit: μm) is 20 μm to 350 μm. Requirement (α2): The pitch of the bumps (BM P ) (unit: μm) and the width of the bump (BM w ) (unit: μm) satisfies the following formula (I). [(BM P ) / (BM w )]≦1.0 (I)

[0186] The above requirements (α1) and (α2) are indicators that indicate that the semiconductor wafer has bumps with narrow pitches, i.e., indicators that indicate that short circuits are likely to occur due to crushing or deformation of the bumps. Bump pitch (BM P ) (unit: μm) and the bump width (BM w ) (unit: μm), an enlarged top view of three bumps BM_a, BM_b, and BM_c formed on the bump formation surface of the wafer 41 is shown in FIG. Bump pitch (BM P ) is the shortest distance between two bumps. In FIG. 7, the shortest distance between bumps BM_a and BM_b is P1. The shortest distance between bumps BM_b and BM_c is P2. Bump width (BM w ) is the length of the straight line b1-b2 connecting the point of contact b1 with the bump BM_b of the straight line P1 connecting the bump BM_a and the bump BM_b, and the point of contact b2 with the bump BM_b of the straight line P2 connecting the bump BM_b and the bump BM_c. In addition, the bump pitch (BM P ) (unit: μm) and the bump width (BM w ) (unit: μm) can be measured based on the above definition, for example, by observation with an optical microscope.

[0187] Furthermore, if the above requirements (α1) to (α2) are satisfied between at least one of the bumps present on the wafer, there is a risk of short-circuiting occurring between the bumps due to the narrow pitch between the bumps. Therefore, the wafer to which the present invention is applied is a wafer that satisfies the above requirements (α1) to (α2) between at least one of the bumps present on the wafer.

[0188] Here, the width of the bump (BM w ) (unit: μm) is 20 μm to 350 μm. That is, according to the present invention, the width (BM w The target may also be a wafer having a plurality of small bumps with a size of 20 μm or more and less than 150 μm (particularly, 20 μm to 100 μm). In other words, the target may also be a wafer having a plurality of fine bumps with a narrow pitch. In addition, the target may also be a wafer having a small bump width (BM w The present invention can also be applied to wafers having a plurality of large bumps with a pitch of 150 μm to 350 μm. In other words, the present invention can be applied to wafers having a plurality of narrow-pitch, wide bumps. Wafers having a plurality of narrow-pitch, wide bumps are particularly prone to short circuits between the bumps, but the present invention can suppress short circuits between the bumps on such wafers.

[0189] Here, requirement (α2) specifies [(BM P ) / (BM w The value of )] is one of the indices that indicates the likelihood of short-circuiting between bumps, and this value may be 0.9 or less, or may be 0.8 or less.

[0190] Here, the wafer may further satisfy the following requirement (α3a) or the following requirement (α3b). Requirement (α3a): The height of the bump (BM h ) and the width of the bump (BM w ) satisfies the following formula (IIIa): 0.2≦[(BM h ) / (BM w )]≦1.0 (IIIa) Requirement (α3b): The height of the bump (BM h ) and the width of the bump (BM w ) and satisfy the following formula (IIIb): 0.5≦[(BM h ) / (BM w )]≦5.0 (IIIb)

[0191] The above requirement (α3a) is an index that indicates that the bump is a ball bump, and [(BM h ) / (BM w The closer the value of )] is to 1.0, the closer it is to a perfect sphere, and the closer it is to 0.2, the closer it is to a spheroid that is elongated in the horizontal direction relative to the bump formation surface 41 a of the wafer 41 . A semiconductor wafer having such ball bumps is singulated into semiconductor chips, and in the process of electrically connecting the semiconductor chips to a wiring substrate via the ball bumps, the ball bumps are crushed and spread laterally, causing contact between the ball bumps and resulting in a short circuit. Furthermore, to meet the demand for even higher density packaging, three-dimensional high-density packaging in which semiconductor packages are stacked vertically is also being considered. In this case, the weight of the semiconductor packages gradually crushes the ball bumps, which can lead to a short circuit. According to the present invention, short circuits caused by contact between ball bumps can be suppressed.

[0192] The above requirement (α3b) is an indicator that the bump is a pillar bump, and [(BM h ) / (BM w The closer the value of )] is to 5.0, the higher the aspect ratio of the pillar bump is, and the closer it is to 0.5, the lower the aspect ratio of the pillar bump is. A semiconductor wafer having such pillar bumps is diced into individual semiconductor chips, and in the process of electrically connecting the semiconductor chips to a wiring substrate via ball bumps, the pillar bumps may deform and bend, causing contact between the pillar bumps and resulting in a short circuit. In addition, the deformation and bending of the pillar bumps can also cause connection defects. Furthermore, to meet demands for even higher density packaging, three-dimensional high-density packaging in which semiconductor packages are stacked in the vertical direction is also being considered. In this case, the pillar bumps may gradually deform due to the weight of the semiconductor package, leading to a short circuit. According to the present invention, short circuits caused by contact between pillar bumps can be suppressed. Furthermore, connection defects that may be caused by pillar bump deformation can also be suppressed.

[0193] In addition, the bump height (BM h ) means, when focusing on one bump, the distance in a straight line connecting the point of contact between the bump on the bump-forming surface and the part of the bump that is farthest from the bump-forming surface. Bump height (BM h ) may specifically be a value defined by the following requirement (α4). Requirement (α4): The height of the bump (BM h ) is 15μm to 300μm That is, in one aspect of the present invention, the bump height (BM h The target may also be a wafer having a plurality of bumps with a low bump height (BM) of 20 μm or more and less than 150 μm (particularly, 20 μm to 100 μm). h The present invention can also be applied to wafers having a plurality of bumps with high surface roughness (150 μm to 350 μm). Bump height (BM h ) can be measured, for example, by cutting a semiconductor wafer with bumps in a direction perpendicular to the bump-forming surface and passing through the center of the bumps, and observing the cross section with an optical microscope.

[0194] <Process (S2)> An outline of step (S2) is shown in FIG. In the step (S2), the sheet for forming a protective film 1 of the present invention is attached to the bump formation surface 41a of the semiconductor wafer 41 while being pressed, with the curable resin film (x) facing the attachment surface. As a result, the bump formation surface 41a of the semiconductor wafer 41 is covered with the curable resin film (x), and the curable resin film (x) is also filled between the plurality of bumps BM.

[0195] The pressure applied when adhering the protective film forming sheet 1 to the bump formation surface 41a of the semiconductor wafer 41 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 filling the curable resin film (x) well between the multiple bumps BM. The pressing force when attaching the protective film forming sheet 1 to the bump formation surface 41a of the semiconductor wafer 41 may be varied as appropriate from the beginning to the end of attachment. For example, from the viewpoint of better filling the curable resin film (x) between the plurality of bumps BM, it is preferable to lower the pressing force at the beginning of attachment and gradually increase the pressing force.

[0196] Furthermore, when the protective film forming sheet 1 is attached to the bump formation surface 41a of the semiconductor wafer 41, if the curable resin film (x) is a thermosetting resin film (x1), it is preferable to heat the curable resin film (x) from the viewpoint of more effectively filling the spaces between the plurality of bumps BM. If the curable resin film (x) is a thermosetting resin film (x1), the fluidity of the thermosetting resin film (x1) temporarily increases when heated, and the thermosetting resin film (x1) hardens when heated continuously. Therefore, by heating within a range that improves the fluidity of the thermosetting resin film (x1), the thermosetting resin film (x1) can easily spread between the plurality of bumps BM, and the filling ability of the thermosetting resin film (x1) between the plurality of bumps BM can be further improved. Specifically, the heating temperature (adhesion temperature) is preferably 50°C to 150°C, more preferably 60°C to 130°C, and even more preferably 70°C to 110°C. The heat treatment performed on the thermosetting resin film (x1) is not included in the curing treatment of the thermosetting resin film (x1).

[0197] Furthermore, the protective film forming sheet 1 may be attached to the bump formation surface 41a of the semiconductor wafer 41 in a reduced pressure environment. This creates a negative pressure between the bumps BM, making it easier for the curable resin film (x) to spread between the bumps BM. As a result, the filling of the curable resin film (x) between the bumps BM is more likely to be improved. The specific pressure of the reduced pressure environment is preferably 0.001 kPa to 50 kPa, more preferably 0.01 kPa to 5 kPa, and even more preferably 0.05 kPa to 1 kPa.

[0198] <Process (S3)> After the step (S2) is performed, the step (S3) is performed. Specifically, as shown in Fig. 9, the curable resin film (x) is cured to obtain a semiconductor wafer with a protective film. The protective film (X) formed by curing the curable resin film (x) is stronger than the curable resin film (x) at room temperature (23°C). Therefore, by forming the protective film (X), the bump neck is well protected. Furthermore, in the present invention, a sheet for forming a protective film that satisfies the above requirements (β1) to (β3) is used, and therefore, as mentioned above, it is possible to suppress the crushing and deformation of bumps on semiconductor wafers having narrow-pitch bumps that may cause short circuits due to the crushing and deformation of the bumps, and to avoid short circuits due to contact between the bumps.

[0199] The curable resin film (x) can be cured by either heat curing or curing by irradiation with energy rays, depending on the type of curable component contained in the curable resin film (x). When thermal curing is carried out, the curing temperature is preferably 90° C. to 200° C., and the curing time is preferably 1 hour to 3 hours. The conditions for curing by energy ray irradiation are appropriately set depending on 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 intensity is preferably 300 mJ / cm 2 ~3000mJ / cm 2 is.

[0200] Here, in the process of curing the curable resin film (x) to form the protective film (X), from the viewpoint of removing air bubbles and the like that may be trapped when the curable resin film (x) fills the spaces between the plurality of bumps BM in step (S2), the curable resin film (x) is preferably a thermosetting resin film (x1). That is, when the curable resin film (x) is a thermosetting resin film (x1), the fluidity of the thermosetting resin film (x1) temporarily increases when heated, and the thermosetting resin film (x1) hardens when heated continuously. By utilizing this phenomenon, when the fluidity of the thermosetting resin film (x1) increases, air bubbles and the like that may be trapped when the thermosetting resin film (x1) fills the spaces between the plurality of bumps BM are removed, and the thermosetting resin film (x1) can be hardened in a state in which the filling ability of the thermosetting resin film (x1) between the plurality of bumps BM is improved. From the viewpoint of shortening the curing time, the curable resin film (x) is preferably an energy ray-curable resin film (x1).

[0201] The support sheet (Y) is peeled off before the curable resin film (x) is cured, and the curable resin film (x) is cured to form the protective film (X), thereby obtaining a semiconductor wafer with a protective film. However, the present invention is not limited to this embodiment, and the support sheet (Y) may be peeled off after the curable resin film (x) is cured to form the protective film (X), thereby obtaining a semiconductor wafer with a protective film. Alternatively, without peeling off the support sheet (Y), the surface of the semiconductor wafer 41 opposite to the bump-forming surface 41a (i.e., the back surface of the semiconductor wafer 41) may be ground (back-grinding process) to thin the semiconductor wafer 41. The back-grinding process may be performed before or after the curable resin film (x) is cured. When back-grinding is performed, the support sheet (Y) is preferably a back-grinding tape in order to perform the back-grinding well.

[0202] Furthermore, after the curable resin film (x) is cured, the protective film (X) covering the top of the bump or the protective film (X) attached to part of the top of the bump may be removed to expose the top of the bump. Examples of the exposure process for exposing the tops of the bumps include etching processes such as wet etching and dry etching. Here, the dry etching process may be, for example, a plasma etching process. If the tops of the bumps are not exposed on the surface of the protective film, the exposing process may be performed to recede the protective film until the tops of the bumps are exposed.

[0203] [Method of manufacturing semiconductor chips with protective film] The method for producing a semiconductor chip with a protective film of the present invention includes the following steps (T1) and (T2). Step (T1): A step of obtaining a semiconductor wafer with a protective film by carrying out the method for producing a semiconductor wafer with a protective film of the present invention. Step (T2): A step of dividing the semiconductor wafer with the protective film into individual pieces.

[0204] <Process (T1)> In the step (T1), the above-described method for producing a semiconductor wafer with a protective film of the present invention is carried out to obtain a semiconductor wafer with a protective film.

[0205] <Process (T2)> In the step (T2), the semiconductor wafer with the protective film obtained in the step (T1) is divided into individual pieces. The method of singulation is not particularly limited, and any known singulation method can be appropriately employed, such as laser dicing, blade dicing, and Stealth Dicing (registered trademark).

[0206] Before carrying out the step (T1), a step of forming a back surface protective film on the back surface (the surface opposite to the bump formation surface) of the semiconductor wafer with the protective film may be included.

[0207] [Semiconductor package manufacturing method] The method for producing a semiconductor package of the present invention includes the following steps (U1) to (U2). Step (U1): A step of obtaining a semiconductor chip with a protective film by carrying out the method for producing a semiconductor chip with a protective film of the present invention. Step (U2): A step of electrically connecting the wiring substrate and the semiconductor chip with the protective film via the bumps.

[0208] <Process (U1)> In the step (U1), the above-described method for producing a semiconductor chip with a protective film of the present invention is carried out to obtain a semiconductor chip with a protective film.

[0209] <Process (U2)> In the step (U2), as shown in FIG. 10, the wiring board (Z) having the wiring Z1 and the semiconductor chip CP with the protective film are electrically connected via bumps BM. More specifically, the bump-forming surface of the protective film-attached semiconductor chip CP and the wiring Z1-forming surface of the wiring substrate (Z) are heated in a state where they face each other with the bumps BM interposed therebetween (hereinafter also referred to as the "heat connection step"). This allows for good electrical connection between the tops of the bumps BM and the wiring Z1. Furthermore, although the present invention uses semiconductor chips obtained from semiconductor wafers having narrowly-pitched bumps that may cause short circuits due to crushing or deformation of the bumps, by satisfying the above requirements (β1) to (β3), and particularly by satisfying the above requirement (β2), contact between bumps due to crushing or deformation of the bumps can be suppressed during the heating connection process, and short circuits caused by contact between bumps can be avoided. The conditions for the heat connection step are, for example, a temperature of 250° C. to 270° C. and a time of 30 seconds to 5 minutes.

[0210] <Process (U3)> The method for producing a semiconductor package according to one aspect of the present invention further includes the following step (U3). Step (U3): A step of filling an underfill material between the wiring substrate and the semiconductor chip with the protective film. As described above, the present invention can prevent bumps from coming into contact with each other due to crushing or deformation of the bumps. In other words, it can prevent bumps from coming into close proximity to each other due to crushing or deformation of the bumps. In the past, when bumps came into close proximity, the gaps between the bumps were narrow, making it difficult to fill the gaps with underfill material. However, the present invention can also prevent bumps from coming into close proximity, making it possible to successfully fill the gaps between the protective film (X) and the wiring substrate (Z) with underfill material, including the gaps between the bumps. [Example]

[0211] The present invention will be specifically described with reference to the following examples, but the present invention is not limited to these examples.

[0212] [Methods for measuring various physical properties] The physical properties in the following examples and comparative examples were measured by the following methods.

[0213] <Weight average molecular weight> Measurement was carried out using a gel permeation chromatograph (manufactured by Tosoh Corporation, product name "HLC-8020") under the conditions below, and the values measured were converted into standard polystyrene equivalents. (Measurement conditions) Column: "TSK guard column HXL-L", "TSK gel G2500HXL", "TSK gel G2000HXL", and "TSK gel G1000HXL" (all manufactured by Tosoh Corporation) connected in series Column temperature: 40℃ Developing solvent: tetrahydrofuran ·Flow rate: 1.0mL / min

[0214] <Measurement of thickness of each layer> Thickness of protective film (after curing) (X T ) The thicknesses other than those were measured using a constant pressure thickness measuring instrument manufactured by Teclock Corporation (model number: "PG-02J", standard specifications: compliant with JIS K6783, Z1702, Z1709).

[0215] <Glass transition temperature> The glass transition temperature (Tg) of the polymer component (A) described below was determined by measuring a temperature profile from -70°C to 150°C at a temperature increase / decrease rate of 10°C / min using a differential scanning calorimeter (PYRIS Diamond DSC) manufactured by PerkinElmer Co., Ltd., and confirming the inflection point.

[0216] <Epoxy equivalent> Measurements were performed in accordance with JIS K 7236:2009.

[0217] <Average particle size> The particles to be measured were dispersed in water using ultrasonic waves, and the particle size distribution of the particles was measured on a volume basis using a dynamic light scattering particle size distribution analyzer (HORIBA Ltd., LB-550). The median diameter (D 50 ) was taken as the average particle size.

[0218] [Examples 1-4, Comparative Examples 1-2] The thermosetting resin composition (x1-1) used in the production of the thermosetting resin film (x1) used in the examples was prepared by the following method.

[0219] <Raw materials for thermosetting resin composition (x1-1)> (Polymer component (A)) Polyvinyl butyral having structural units represented by the following formulae (i-1), (i-2), and (i-3) (S-LEC (registered trademark) B BL-10, manufactured by Sekisui Chemical Co., Ltd., weight average molecular weight 25,000, glass transition temperature 59°C, in the following formulae, p is 68 to 74 mol%, q is 1 to 3 mol%, and r is approximately 28 mol%) was used. [ka]

[0220] (Epoxy resin (B1)) The following two types of epoxy resins were used: Epoxy resin (B1-1): Liquid bisphenol A type epoxy resin (DIC Corporation, EPICLON (registered trademark) EXA-4850-1000, epoxy equivalent 404 to 412 g / eq) Epoxy resin (B1-2): dicyclopentadiene-type epoxy resin (manufactured by DIC Corporation, EPICLON (registered trademark) HP-7200, epoxy equivalent 254 to 264 g / eq)

[0221] (Thermal curing agent (B2)) A novolac type phenolic resin (Shonoru (registered trademark) BRG-556, manufactured by Showa Denko KK) was used.

[0222] (Curing accelerator (C)) 2-phenyl-4,5-dihydroxymethylimidazole (Curezol (registered trademark) 2PHZ, manufactured by Shikoku Chemicals Corporation) was used.

[0223] (Filling material (D)) Spherical silica modified with epoxy groups (manufactured by Admatechs Co., Ltd., Admanano (registered trademark) YA050C-MKK, average particle size 0.05 μm) was used.

[0224] <Preparation of Thermosetting Resin Composition (x1-1)> The polymer component (A), the epoxy resin (B1-1), the epoxy resin (B1-2), the heat curing agent (B2), the curing accelerator (C), and the filler (D) were dissolved or dispersed in methyl ethyl ketone so as to have the contents shown below based on the total amount (100 mass%) of the thermosetting resin composition (x1-1), and the mixture was stirred at 23°C to prepare a thermosetting resin composition (x1-1) having an active ingredient (solid content) concentration of 55 mass%. In Examples 1 and 2, the protective film (X) was formed using a thermosetting resin composition (x1-1) prepared according to the following formulation 1. In Examples 3 and 4, the protective film (X) was formed using a thermosetting resin composition (x1-1) prepared according to the following formulation 2. (Formulation 1) ·Polymer component (A): 41.4% by mass Epoxy resin (B1-1): 23.2% by mass Epoxy resin (B1-2): 15.2% by mass ·Thermosetting agent (B2): 11.2% by mass ·Curing accelerator (C): 0.2% by mass ·Filler (D): 8.8% by mass (Formulation 2) ·Polymer component (A): 19.9% by mass Epoxy resin (B1-1): 33.1% by mass Epoxy resin (B1-2): 21.7% by mass ·Thermosetting agent (B2): 16.1% by mass ·Curing accelerator (C): 0.2% by mass ·Filler (D): 9.0% by mass

[0225] <Production of thermosetting resin film (x1)> The thermosetting resin composition (x1-1) prepared in Blend 1 was applied to the release-treated surface of a polyethylene terephthalate release liner (SP-PET381031, manufactured by Lintec Corporation, thickness 38 μm) having a release-treated surface treated with silicone, and the applied surface was dried by heating at 120°C for 2 minutes to obtain a thermosetting resin film (x1: Blend 1) having a thickness of 30 μm. A thermosetting resin film (x1: Blend 2) having a thickness of 50 μm was also obtained in the same manner, except that the thermosetting resin composition (x1-1) prepared in Blend 2 was used instead.

[0226] <Production of protective film forming sheet> As the support sheet (Y), an adhesive tape (E-8510HR, manufactured by Lintec Corporation) consisting of a substrate (thickness: 100 μm), an intermediate layer (thickness: 400 μm), and an adhesive layer (thickness: 10 μm) laminated in this order was used, and the adhesive layer of this adhesive tape was bonded to a 30 μm thick thermosetting resin film (x1: Blend 1) formed on a release material to produce a protective film forming sheet 1 consisting of the support sheet (Y), thermosetting resin film (x1), and release material laminated in this order. A sheet for forming a protective film 2 was also produced using a 50 μm thick thermosetting resin film (x1: Blend 2) in the same manner.

[0227] [Measurement of tensile modulus E' of protective film (X)] After the thermosetting resin film (x1) was cured, the tensile modulus E' of the protective film (X) was measured by the following method. First, six 30 μm thick thermosetting resin films (x1: Blend 1) were stacked to prepare a sample with a thickness of 0.18 mm, a width of 4.5 mm, and a length of 20.0 mm. The sample was then heat-treated in a pressure oven (RAD-9100 manufactured by Lintec Corporation) under heating conditions of a temperature of 130°C, a time of 2 hours, and an internal furnace pressure of 0.5 MPa to obtain a protective film (X). Next, the tensile modulus E' (23°C) of the protective film (X) was measured in tension mode using a dynamic viscoelasticity measuring device (manufactured by TA instruments, product name "DMA Q800") at a frequency of 11 Hz, 23°C, and atmospheric pressure. The tensile modulus E' (260°C) of the protective film (X) was also measured under the same conditions except that the temperature during measurement was set to 260°C. For the thermosetting resin film (x1: Blend 2), a protective film (X) was obtained using the same procedure, except that four 50 μm thick thermosetting resin films (x1: Blend 2) were stacked to a thickness of 0.20 mm, and the tensile modulus E' (23°C) of the protective film (X) and the tensile modulus E' (260°C) of the protective film (X) were measured.

[0228] [Short-circuit evaluation] The release material was removed from the protective film-forming sheet obtained above, and the exposed surface of the thermosetting resin layer (exposed surface) was pressed against the bump-forming surface of the semiconductor wafer to attach the protective film-forming sheet to the bump-forming surface of the semiconductor wafer. The protective film-forming sheet was attached using an attachment device (a roller-type laminator, manufactured by Lintec Corporation, model RAD-3510 F / 12) at a table temperature of 90°C, an attachment speed of 2 mm / sec, and an attachment pressure of 0.5 MPa while heating the thermosetting resin film (x1). Details of the ball-bumped wafers to which protective film-forming sheets 1 and 2 were attached (requirements (α1), (α2), (α3a), and (α4)) are shown in Table 1. Next, ultraviolet light was irradiated using RAD-2700 manufactured by Lintec Corporation, and the support sheet (Y) of the sheet for forming a protective film was peeled off. The bumped wafer with the thermosetting resin film (x1) attached thereto was heat-treated in a pressure oven (RAD-9100 manufactured by Lintec Corporation) under heating conditions of temperature: 130°C, time: 2 hours, and furnace pressure: 0.5 MPa to thermally cure the thermosetting resin film (x1), thereby obtaining semiconductor wafers with a protective film (X) (Examples 1 to 4). Thickness of protective film (X) T) was measured by cutting the semiconductor wafer with the protective film (X) in a direction perpendicular to the bump-forming surface and passing through the center of the bump, and observing the cut cross section with an optical microscope. Then, the bump-forming surface of the semiconductor wafer with the protective film (X) and the wiring-forming surface of the wiring board were placed opposite each other with the bumps interposed between them, and a heat treatment (heat connection process) was carried out at 260°C for 1 minute, and the presence or absence of contact between the bumps (presence or absence of short circuit) was evaluated. As a comparative test, a thermal connection process was carried out on wafers with bumps similar to those in Examples 1 and 3 and Examples 2 and 4, but without a protective film (X), and the presence or absence of short circuits was evaluated (Comparative Examples 1 and 2). The results are shown in Table 1.

[0229] [Table 1]

[0230] Table 1 reveals the following: It can be seen that in Examples 1 to 4, short-circuiting of the bumps can be suppressed despite the use of semiconductor wafers having bumps with narrower pitches. On the other hand, when the protective film (X) is not provided as in Comparative Examples 1 and 2, it is clear that short-circuiting of bumps in a semiconductor wafer having bumps with narrow pitches cannot be suppressed. [Explanation of symbols]

[0231] 1, 1a, 1b, 1c Protective film forming sheet x Hardening resin film x1 Thermosetting Resin Film x2 Energy ray curable resin film X Protective film Y Support Sheet 11 Base material 21 adhesive layer 31 Middle Class 40 Bumped semiconductor wafer 41 Semiconductor wafers 41a Bump forming surface BM Bump CP Semiconductor chip with protective film Z wiring board Z1 wiring

Claims

1. A sheet for forming a protective film having a laminated structure of a curable resin film (x) and a support sheet (Y), the curable resin film (x) is a thermosetting resin film (x1) containing a polymer component (A) including polyvinyl acetal and a thermosetting component including an epoxy resin (B1), The present invention is used to form a protective film (X) on a bump-forming surface of a semiconductor wafer having a plurality of bumps and satisfying the following requirements (α1) to (α2): Requirement (α1): The width of the bump (BM ｗ ) (unit: μm) is 20 μm to 350 μm. Requirement (α2): The pitch of the bumps (BM Ｐ ) (unit: μm) and the width of the bump (BM ｗ ) (unit: μm) satisfy the following formula (I). [(BM) Ｐ ) / (BM ｗ )]≦1.0・・・・(I) A sheet for forming a protective film, which satisfies the following requirements (β1) to (β3): Requirement (β1): The protective film (X) formed by curing the curable resin film (x) has a tensile modulus E′ (23° C.) at 23° C. of 1×10 ７ Pa ~ 1 x 10 １０ It is Pa. Requirement (β2): The protective film (X) formed by curing the curable resin film (x) has a tensile modulus E′ (260°C) at 260°C of 1×10 ５ Pa ~ 1 x 10 ８ It is Pa. Requirement (β3): The thickness (X) of the protective film (X) formed by curing the curable resin film (x) at 23°C Ｔ ) (unit: μm) and the height of the bump (BM ｈ ) (unit: μm) satisfy the following formula (II). [(︸ Ｔ )|(#* ｈ ≽≧|.(･･･(E))

2. A sheet for forming a protective film having a laminated structure of a curable resin film (x) and a support sheet (Y), The present invention is used to form a protective film (X) on a bump-forming surface of a semiconductor wafer having a plurality of bumps and satisfying the following requirements (α1) to (α2): Requirement (α1): The width (BM w ) (unit: μm) of the bump is 20 μm to 350 μm. Requirement (α2): The bump pitch (BM P ) (unit: μm) and the bump width (BM W ) (unit: μm) satisfy the following formula (I). [(BM P ) / (BM w )]≦0.70...(I) A sheet for forming a protective film, which satisfies the following requirements (β1) to (β3): Requirement (β1): The protective film (X) formed by curing the curable resin film (x) has a tensile modulus E′ (23° C.) at 23° C. of 1×10 7 Pa to 1×10 10 Pa. Requirement (β2): The protective film (X) formed by curing the curable resin film (x) has a tensile modulus E′(260° C.) at 260° C. of 1×10 5 Pa to 1×10 8 Pa. Requirement (β3): The thickness (X T ) (unit: μm) at 23° C. of the protective film (X) formed by curing the curable resin film (x) and the height (BM h ) (unit: μm) of the bump satisfy the following formula (II): [(X T ) / (BM h )]≧0.2 (II)

3. The sheet for forming a protective film according to claim 1 or 2, further satisfying the following requirement (α3a): Requirement (α3a): The height of the bump (BM ｈ ) and the width of the bump (BM ｗ ) satisfies the following formula (IIIa): 0.2≦[(BM ｈ ) / (BM ｗ )]≦1.0・・・・(---a)

4. The sheet for forming a protective film according to claim 1 or 2, further satisfying the following requirement (α3b): Requirement (α3b): The height of the bump (BM ｈ ) and the width of the bump (BM ｗ ) satisfies the following formula (IIIb): 0.5≦[(BM) ｈ ) / (BM ｗ )]≦5.0・・・・(IIIｬ)

5. The sheet for forming a protective film according to any one of claims 1 to 4, further satisfying the following requirement (α4): Requirement (α4): The height of the bump (BM ｈ ) is 15 μm to 300 μm

6. The sheet for forming a protective film according to any one of claims 1 to 5, wherein the support sheet (Y) is a backgrind tape.

7. A method for manufacturing a semiconductor wafer with a protective film, comprising: The method includes the following steps (S1) to (S3): Step (S1): A step of preparing a semiconductor wafer having a bump-forming surface on which a plurality of bumps are provided. Step (S2): A step of adhering the sheet for forming a protective film according to claim 1 to the bump-forming surface of the semiconductor wafer while pressing the curable resin film (x) as an attachment surface. Step (S3): A step of curing the curable resin film (x) to form a protective film (X) The method for producing a semiconductor wafer with a protective film, wherein the semiconductor wafer prepared in the step (S1) satisfies the following requirements (α1) to (α2): Condition (α1): The width of the bump (BM ｗ ) (unit: μm) is 20 μm to 350 μm Condition (α2): The pitch of the bumps (BM Ｐ ) (unit: μm) and the width of the bump (BM ｗ ) (unit: μm) satisfy the following formula (I): [(BM) Ｐ ) / (BM ｗ )]≦1.0・・・・(I)

8. A method for manufacturing a semiconductor wafer with a protective film, comprising: The method includes the following steps (S1) to (S3): Step (S1): A step of preparing a semiconductor wafer having a bump-forming surface on which a plurality of bumps are provided. Step (S2): A step of adhering the sheet for forming a protective film according to claim 2 to the bump-forming surface of the semiconductor wafer while pressing the curable resin film (x) as an attachment surface. Step (S3): A step of curing the curable resin film (x) to form a protective film (X) The method for producing a semiconductor wafer with a protective film, wherein the semiconductor wafer prepared in the step (S1) satisfies the following requirements (α1) to (α2): Condition (α1): The width (BM w ) of the bump (unit: μm) is 20 μm to 350 μm. Condition (α2): The bump pitch (BM P ) (unit: μm) and the bump width (BM W ) (unit: μm) satisfy the following formula (I): [(BM P ) / (BM w )]≦0.70...(I)

9. A method for manufacturing a semiconductor chip with a protective film, comprising the following steps (T1) to (T2): Step (T1): A step of obtaining a semiconductor wafer with a protective film by carrying out the manufacturing method according to claim 7 or 8. Step (T2): step of dividing the semiconductor wafer with the protective film into individual pieces

10. A method for manufacturing a semiconductor package, comprising the following steps (U1) to (U2): Step (U1): A step of obtaining a semiconductor chip with a protective film by carrying out the manufacturing method according to claim 9. Step (U2): A step of electrically connecting the wiring substrate and the semiconductor chip with the protective film via the bumps.

11. The method for manufacturing a semiconductor package according to claim 10, further comprising a step (U3). Step (U3): A step of filling an underfill material between the wiring substrate and the semiconductor chip with the protective film.

Images