Protective film forming sheet

Abstract

The present invention aims to provide a protective film-forming sheet capable of suppressing short circuits between bumps with narrowed pitches. This problem is solved by forming a protective film-forming sheet having a laminated structure of a curable resin film (x) and a support sheet (Y), the sheet being used to form a protective film (X) on the bump-forming surface of a semiconductor wafer having a plurality of bumps and meeting specific requirements for having narrowed-pitch bumps, wherein the protective film-forming sheet meets the specific requirements defined by a tensile modulus E'.

Description

Technical Field

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

[0002] Conventionally, when mounting multi-pin LSI packages used in MPUs, gate arrays, and other devices on printed wiring boards, semiconductor chips with protruding electrodes (hereinafter referred to as "bumps") formed on their connection pads have been used. This is done using a flip-chip mounting method, where these bumps are brought into face-to-face contact with corresponding terminals on the chip mounting substrate, followed by fusion / diffusion bonding.

[0003] In recent years, as electronic devices have become smaller, lighter, thinner, and more functional, high-density packaging has become increasingly common. Patent documents 1 to 3 propose solder materials with low α-radiation content to avoid issues associated with high-density packaging, namely, soft errors caused by α-radiation penetrating memory cells of semiconductor integrated circuits, which can overwrite stored data.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 4472752

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2011-214040

[0008] Patent Document 3: International Publication No. 2012 / 120982 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] However, as the demand for high-density installation of electronic components increases, the demand for narrower pitch of bumps on semiconductor chips is also increasing. However, when the bumps on semiconductor chips are narrowed, new problems arise. For example, in the process of electrically connecting the semiconductor chip to the wiring substrate via ball bumps, the ball bumps are flattened and expanded in the lateral direction, resulting in the problem of short circuits caused by contact between the ball bumps. In addition, in order to meet the demand for further high-density installation, three-dimensional high-density installation in which semiconductor packages are stacked in the height direction has also been explored. In this case, the ball bumps are gradually flattened by the weight of the semiconductor package, which sometimes causes short circuits.

[0011] In light of the aforementioned issues, the inventors conducted in-depth research and developed a sheet for forming a protective film that prevents ball bumps from flattening and expanding laterally. Furthermore, for semiconductor chips with stud bumps, the inventors also considered the potential for stud bumps to contact each other due to bending, which can cause short circuits. The inventors found that the developed sheet is also effective in addressing this issue with stud bumps.

[0012] 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 narrowed pitches.

[0013] Solutions to Problems

[0014] The present inventors have discovered that the above-mentioned problems can be solved by the following invention.

[0015] That is, the present invention relates to the following [1] to [9].

[0016] [1] A protective film-forming sheet having a laminated structure of a curable resin film (x) and a support sheet (Y),

[0017] The protective film forming sheet is used for forming a protective film (X) on the bump formation surface of a semiconductor wafer having a plurality of bumps and satisfying the following requirements (α1) to (α2).

[0018] Requirement (α1): The width of the bump (BM w )(unit: μm) is 20μm to 350μm.

[0019] 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).

[0020] [(BM P ) / (BM w )]≤1.0····(I)

[0021] The protective film-forming sheet satisfies the following requirements (β1) to (β3).

[0022] 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~1×10 10 Pa.

[0023] 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~1×108 Pa.

[0024] Requirement (β3): The thickness (X) of the protective film (X) formed by curing the curable resin film (x) at 23°C is T ) (unit: μm) and the height of the bump (BM h )(unit: μm) satisfies the following formula (II).

[0025] [(X T ) / (BM h )]≥0.2····(II).

[0026] [2] The protective film forming sheet according to [1], further satisfying the following requirement (α3a).

[0027] Requirement (α3a): The height of the bump (BM h ) and the width of the bump (BM w ) satisfies the following formula (IIIa),

[0028] 0.2≤[(BM h ) / (BM w )]≤1.0····(IIIa).

[0029] [3] The protective film forming sheet according to [1], further satisfying the following requirement (α3b).

[0030] Requirement (α3b): The height of the bump (BM h ) and the width of the bump (BM w ) satisfies the following formula (IIIb),

[0031] 0.5≤[(BM h ) / (BM w )]≤5.0····(IIIb).

[0032] [4] The protective film forming sheet according to any one of [1] to [3], further satisfying the following requirement (α4).

[0033] Requirement (α4): The height of the bump (BM h ) is 15μm~300μm.

[0034] [5] The protective film-forming sheet according to any one of [1] to [4], wherein

[0035] The above-mentioned supporting sheet (Y) is a back grinding tape.

[0036] [6] A method for manufacturing a semiconductor wafer with a protective film, the method comprising the following steps (S1) to (S3):

[0037] Step (S1): a step of preparing a semiconductor wafer having a bump formation surface provided with a plurality of bumps;

[0038] Step (S2): a step of laminating the protective film forming sheet according to any one of [1] to [5] to the bump formation surface of the semiconductor wafer while pressing the sheet with the curable resin film (x) as the adhesive surface;

[0039] Step (S3): a step of curing the curable resin film (x) to form a protective film (X).

[0040] The semiconductor wafer prepared in the step (S1) satisfies the following requirements (α1) to (α2).

[0041] Requirement (α1): The width of the bump (BM w )(unit: μm) is 20 μm to 350 μm,

[0042] 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),

[0043] [(BM P ) / (BM w )]≤1.0····(I).

[0044] [7] A method for manufacturing a semiconductor chip with a protective film, the method comprising the following steps (T1) to (T2):

[0045] Step (T1): a step of implementing the manufacturing method described in [6] to obtain a semiconductor wafer with a protective film,

[0046] Step (T2): a step of separating the semiconductor wafer with the protective film into individual pieces.

[0047] [8] A method for manufacturing a semiconductor package, the method comprising the following steps (U1) to (U2):

[0048] Step (U1): a step of implementing the manufacturing method described in [7] to obtain a semiconductor chip with a protective film,

[0049] Step (U2): A step of electrically connecting the wiring substrate and the semiconductor chip with the protective film via the bumps.

[0050] [9] The method for manufacturing a semiconductor package according to [8], further comprising a step (U3),

[0051] Step (U3): A step of filling an underfill material between the wiring substrate and the semiconductor chip with a protective film.

[0052] Effects of the Invention

[0053] According to the present invention, a protective film forming sheet capable of suppressing short circuits between bumps with narrowed pitches can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a schematic cross-sectional view showing the structure of the protective film-forming sheet of the present invention.

[0055] Figure 2 This is a schematic cross-sectional view showing an example of the structure of a protective film forming sheet according to one embodiment of the present invention.

[0056] Figure 3 This is a schematic cross-sectional view showing another example of the structure of the protective-film-forming sheet according to one embodiment of the present invention.

[0057] Figure 4 This is a schematic cross-sectional view showing another example of the structure of the protective-film-forming sheet according to one embodiment of the present invention.

[0058] Figure 5 1 is a schematic cross-sectional view showing an example of a semiconductor wafer having a plurality of bumps.

[0059] Figure 6 1 is a schematic cross-sectional view showing another example of a semiconductor wafer having a plurality of bumps.

[0060] Figure 7 is used for the pitch of the bumps (BM P ) and the width of the bump (BM w ) is a top view of three bumps on a semiconductor chip that are defined and enlarged.

[0061] Figure 8 This 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.

[0062] Figure 9 This 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.

[0063] Figure 10 This is a schematic cross-sectional view illustrating step ( U2 ) of the method for manufacturing a semiconductor package according to one embodiment of the present invention.

[0064] Figure 11 is the height of the bump (BM h) (unit: μm) and the thickness (X) of the protective film (X) formed by curing the curable resin film (x) at 23°C T )(unit: μm).

[0065] Explanation of symbols

[0066] 1, 1a, 1b, 1c Sheets for forming protective film

[0067] X curable resin film

[0068] x1 Thermosetting resin film

[0069] x2 Energy ray curable resin films

[0070] X Protective Film

[0071] Y support piece

[0072] 11. Substrate

[0073] 21 Adhesive layer

[0074] 31 Middle Layer

[0075] 40 Semiconductor wafer with bumps

[0076] 41 semiconductor chips

[0077] 41a Bump formation surface

[0078] BM Bump

[0079] CP semiconductor chip with protective film

[0080] Z wiring substrate

[0081] Z1 wiring DETAILED DESCRIPTION

[0082] In this specification, the "active ingredient" refers to the components contained in the target composition excluding diluents such as water and organic solvents.

[0083] In addition, in this specification, "(meth)acrylic acid" means both "acrylic acid" and "methacrylic acid", and the same applies to other similar terms.

[0084] In addition, in this specification, the weight average molecular weight and the number average molecular weight are polystyrene-equivalent values ​​measured by gel permeation chromatography (GPC).

[0085] In addition, in this specification, for preferred numerical ranges (e.g., content ranges), the lower limit and upper limit values ​​described in steps can be independently combined. For example, from the description "preferably 10 to 90, more preferably 30 to 60", the "preferable lower limit (10)" and the "more preferably upper limit (60)" can be combined to obtain "10 to 60".

[0086] [Form of protective film forming sheet]

[0087] The protective film-forming sheet of the present invention has a laminated structure of a curable resin film (x) and a support sheet (Y).

[0088] The protective film forming sheet of the present invention is used for forming a protective film (X) on the bump formation surface of a semiconductor wafer having a plurality of bumps and satisfying the following requirements (α1) to (α2).

[0089] Requirement (α1): The width of the bump (BM w )(unit: μm) is 20μm to 350μm.

[0090] 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).

[0091] [(BM P ) / (BM w )]≤1.0····(I)

[0092] Furthermore, the protective film-forming sheet of the present invention satisfies the following requirements (β1) to (β3).

[0093] 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~1×10 10 Pa.

[0094] 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 Pa.

[0095] Requirement (β3): The thickness (X) of the protective film (X) formed by curing the curable resin film (x) at 23°C is T )(unit: μm) and the height of the bump (BM h )(unit: μm) satisfies the following formula (II).

[0096] [(X T ) / (BM h )]≥0.2····(II)

[0097] Specifically, the protective film-forming sheet of the present invention is used for the bump-forming surface of a semiconductor wafer having narrowed-pitch bumps that satisfies the aforementioned requirements (α1) and (α2). Furthermore, the protective film-forming sheet of the present invention has a laminated structure of a curable resin film (x) and a support sheet (Y) as a specific configuration, and satisfies the aforementioned requirements (β1) to (β3) regarding the curable resin film (x).

[0098] The present inventors have discovered that by using a protective film forming sheet having a stacked structure of a curable resin film (x) and a supporting sheet (Y) and satisfying the above-mentioned requirements (β1) to (β3) related to the curable resin film (x), a protective film (X) is formed on the bump forming surface of a semiconductor chip having bumps with narrow pitches that satisfy the above-mentioned requirements (α1) to (α2), thereby suppressing the flattening and deformation of the bumps and suppressing short circuits between the bumps with narrow pitches.

[0099] Hereinafter, the above-mentioned requirements (β1) to (β3) regarding the protective film (X) defined in the protective film-forming sheet of the present invention will be described.

[0100] <Requirements (β1)>

[0101] The requirement (β1) specifies 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 Pa.

[0102] Tensile modulus E'(23℃) is less than 1×10 7 At Pa, the protective film (X) cannot suppress the flattening and deformation of the bumps, and there is a risk that the bumps may come into contact with each other and cause a short circuit.

[0103] On the other hand, the tensile modulus E'(23℃) exceeds 1×10 10 When the value is greater than 0.05 Pa, stress increases during heating and cooling, which puts a load on the bump and reduces reliability.

[0104] Here, from the viewpoint of more easily suppressing the collapse and deformation of the bumps and suppressing the load applied to the bumps during heating and cooling, the tensile modulus E'(23°C) of the protective film (X) formed by curing the curable resin film (x) at 23°C is preferably 3×10 7 Pa~8×10 9 Pa, more preferably 5×10 7 Pa~7×109 Pa, more preferably 7×10 7 Pa~6×10 9 Pa.

[0105] The protective film (X) having the tensile modulus E' (23°C) defined by the requirement (β1) can be formed by curing the curable resin film (x). The method for preparing the curable resin film (x) for forming the protective film (X) will be described later.

[0106] <Requirements (β2)>

[0107] The requirement (β2) specifies 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 Pa.

[0108] Tensile modulus E'(260℃) is less than 1×10 5 Pa, especially within the heating temperature range (for example, 250°C to 270°C) in the process of electrically connecting the wiring substrate to the semiconductor chip having the bumps via the bumps, the protective film (X) cannot suppress the flattening and deformation of the bumps, and there is a risk of the bumps contacting each other and causing a short circuit.

[0109] On the other hand, the tensile modulus E'(260℃) exceeds 1×10 8 When the value is greater than Pa, stress increases during heating and cooling, which applies a load to the bumps, thereby reducing reliability and bonding properties.

[0110] Here, from the viewpoint of more easily suppressing the collapse and deformation of the bumps and suppressing the load applied to the bumps during heating and cooling, the tensile modulus E'(260°C) of the protective film (X) formed by curing the curable resin film (x) at 260°C is preferably 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 Pa.

[0111] The protective film (X) having the tensile modulus E' (260°C) defined by requirement (β2) can be formed by curing the curable resin film (x). The method for preparing the curable resin film (x) for forming the protective film (X) will be described later.

[0112] <Requirements (β3)>

[0113] The requirement (β3) defines 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 Specifically, the following formula (II) is satisfied.

[0114] [(X T ) / (BM h )]≥0.2····(II)

[0115] [(X T ) / (BM h )]<0.2, the covering height of the protective film (X) is relative to the height of the bump (BM h ) is insufficient, and the protective film (X) cannot suppress the flattening and deformation of the bumps, and there is a risk of the bumps contacting each other and causing a short circuit.

[0116] It should be noted that [(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 top from the protective film (X).

[0117] Here, from the viewpoint of more easily suppressing the collapse and deformation of the bump and exposing the bump top from the protective film (X), in the requirement (β3), the following formula (IIa) is preferably satisfied.

[0118] P≤[(X T ) / (BM h )]≤Q····(IIa)

[0119] In formula (IIa), P is 0.2, preferably 0.30, more preferably 0.40, and even more preferably 0.50.

[0120] In formula (IIa), Q is preferably 1.0, more preferably 0.90, and even more preferably 0.80.

[0121] It should be noted that the thickness of the curable resin film (x) that satisfies the relationship defined by requirement (β3) can be adjusted based on information such as 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 the height of the bumps of the semiconductor chip to be used.

[0122] Figure 11 The height of the bump (BM h ) (unit: μm) and the thickness (X) of the protective film (X) formed by curing the curable resin film (x) at 23°CT )(unit: μm).

[0123] like Figure 11 As shown, the thickness (X) of the protective film (X) formed by curing the curable resin film (x) at 23°C is T ) (unit: μm) refers to the measurement of the bump height (BM h ) of the bump (bump BM), the height from the bump forming surface 41a at a position 50 farthest from the bump forming surface 41a in the contact portion between the bump and the protective film (X).

[0124] Among them, the position 50 farthest from the bump forming surface 41a is determined in the area where the protective film (X) formed on the bump forming surface 41a continuously exists. 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) that exists locally on the top of the bump and is removed by the exposure treatment (plasma etching treatment) described later and the bump. In addition, when the exposure treatment (plasma etching treatment) described later is performed, the thickness of the protective film (X) formed by the exposure treatment after retreating needs to satisfy the above formula (II) (being 0.2μm or more). That is, regardless of whether the exposure treatment described later is performed, the thickness of the protective film (X) must satisfy the above formula (II) (being 0.2μm or more) before the process of electrically connecting the semiconductor chip to the wiring substrate via the ball bump is about to be performed.

[0125] Bump height (BM h ) and the thickness (X) 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 through the center of the bump, and observing the cut cross section under an optical microscope.

[0126] Hereinafter, the protective film-forming sheet of the present invention will be described in detail based on a method for producing a curable resin film (x) for forming a protective film (X) satisfying the requirements (β1) and (β2).

[0127] 《Composition of Sheet for Forming Protective Film》

[0128] The configuration of the protective film forming sheet of the present invention is shown in Figure 1 .

[0129] A protective film forming sheet according to one embodiment of the present invention is Figure 1The protective film forming sheet 1 shown in the figure has a curable resin film (x) on one side of the support sheet (Y). By having the curable resin film (x) on one side of the support sheet (Y), the curable resin film (x) is stably supported and protected when the curable resin film (x) is transported as a product package or when the curable resin film (x) is transported within the process.

[0130] In addition, the structure of the protective film forming sheet of one embodiment of the present invention is shown in Figures 2-4 .

[0131] A protective film forming sheet according to one embodiment of the present invention is Figure 2 As shown in the protective film forming sheet 1 a , the support sheet (Y) is a base material 11 , and a curable resin film (x) is provided on one surface of the base material 11 .

[0132] In addition, a protective film forming sheet according to one embodiment of the present invention is Figure 3 Like the protective film-forming sheet 1 b shown, the support sheet (Y) is an adhesive sheet in which a base material 11 and an adhesive layer 21 are laminated. The adhesive layer 21 of the adhesive sheet can be bonded to the curable resin film (x).

[0133] Furthermore, a protective film forming sheet according to one embodiment of the present invention is Figure 4 As shown in the protective film forming sheet 1c, the support sheet (Y) is an adhesive sheet in which a base material 11, an intermediate layer 31 and an adhesive layer 21 are laminated in this order, and the adhesive layer 21 of the adhesive sheet can be bonded to the curable resin film (x). The adhesive sheet in which a base material 11, an intermediate layer 31 and an adhesive layer 21 are laminated in this order can be suitably used as a back grinding tape. That is, Figure 4 Since the protective film forming sheet 1c shown has a back grinding tape as a support sheet (Y), it can be suitably used when thinning the semiconductor wafer by grinding the side opposite to the bump forming surface of the semiconductor wafer (hereinafter also referred to as the "back side of the semiconductor wafer") after the curable resin film (x) of the protective film forming sheet 1c is bonded to the bump forming surface of the semiconductor wafer having multiple bumps.

[0134] Hereinafter, the curable resin film (x) and the support sheet (Y) used for the protective film-forming sheet of the present invention will be described.

[0135] 《Curable resin film (x)》

[0136] The curable resin film (x) is a film for protecting the bump-forming surface of a semiconductor wafer having a plurality of bumps, and is cured by heating or energy beam irradiation to form a protective film (X). That is, the curable resin film (x) may be a thermosetting resin film (x1) that is cured by heating, or an energy beam curable resin film (x2) that is cured by energy beam irradiation.

[0137] In this specification, "energy rays" refer to radiation having energy quanta among electromagnetic waves or charged particle beams. Examples thereof include ultraviolet rays and electron beams, with ultraviolet rays being preferred.

[0138] 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).

[0139] Hereinafter, the thermosetting resin film (x1) and the energy ray-curable resin film (x2) will be described.

[0140] <Thermosetting resin film (x1)>

[0141] The thermosetting resin film (x1) contains a polymer component (A) and a thermosetting component (B).

[0142] The thermosetting resin film (x1) is formed of, for example, a thermosetting resin composition (x1-1) containing a polymer component (A) and a thermosetting component (B).

[0143] The polymer component (A) can be considered to be a component formed by a polymerization reaction of a polymerizable compound. Furthermore, the thermosetting component (B) is a component that can undergo a curing (polymerization) reaction using heat as a triggering factor for the reaction. It should be noted that this curing (polymerization) reaction also includes a condensation reaction.

[0144] It should be noted that, in the following description of this specification, “the content of each component in the total amount of effective ingredients of the thermosetting resin composition (x1-1)” and “the content of each component in the thermosetting resin film (x1) formed by the thermosetting resin composition (x1-1)” have the same meaning.

[0145] (Polymer component (A))

[0146] The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) refer to the polymer component (A).

[0147] The polymer component (A) is a polymer compound for imparting film-forming properties, flexibility, etc. to the thermosetting resin film (x1). One 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, their combination and ratio may be arbitrarily selected.

[0148] Examples of the polymer component (A) include polyvinyl acetal, acrylic resins (resins having a (meth)acryloyl group), polyesters, urethane resins (resins having a urethane bond), acrylic urethane resins, silicone resins (resins having a siloxane bond), rubber resins (resins having a rubber structure), phenoxy resins, and thermosetting polyimides. These may be used alone or in combination of two or more.

[0149] Among them, at least one selected from polyvinyl acetal and acrylic resins is preferred.

[0150] Hereinafter, polyvinyl acetal and acrylic resin which are preferable as a polymer component (A) are demonstrated as an example.

[0151] Polyvinyl acetal

[0152] The polyvinyl acetal used as the polymer component (A) is not particularly limited, and for example, a known polyvinyl acetal can be used.

[0153] Here, among the polyvinyl acetals, for example, polyvinyl formal, polyvinyl butyral, etc. can be mentioned, and polyvinyl butyral is more preferable.

[0154] From the viewpoint of improving the adhesion between the bump formation surface of the semiconductor wafer and the protective film (X), the polyvinyl butyral preferably has structural units represented by the following formulae (i-1), (i-2), and (i-3).

[0155] [Chemical Formula 1]

[0156]

[0157] In the above formulae (i-1), (i-2) and (i-3), p, q and r are the content ratios (mol %) of the respective structural units.

[0158] The weight average molecular weight (Mw) of the polyvinyl acetal is preferably 5,000 to 200,000, more preferably 8,000 to 100,000, further preferably 9,000 to 80,000, and even more preferably 10,000 to 50,000. By setting the weight average molecular weight of the polyvinyl acetal to this range, it is easy to improve the adhesion between the bump-forming surface of the semiconductor wafer and the protective film (X). In addition, the effect of suppressing the residual protective film (X) on the upper part of the bump (the top of the bump and the area near the bump) is further improved.

[0159] The content ratio p (degree of butyralization) of the structural units of the butyral group represented by the above formula (i-1) is preferably 40 to 90 mol%, more preferably 50 to 85 mol%, and even more preferably 60 to 76 mol%, based on all the structural units of the polymer component (A).

[0160] The content ratio 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).

[0161] The content ratio 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).

[0162] The glass transition temperature (Tg) of the polyvinyl acetal is preferably 40 to 80° C., more preferably 50 to 70° C. By setting the Tg of the polyvinyl acetal within this range, when the thermosetting resin film (x1) is attached to the bump-forming surface of a wafer with bumps, the effect of suppressing the protective film (X) from remaining on the bumps is further improved, and the hardness of the protective film formed by thermally curing the thermosetting resin layer can be made sufficient.

[0163] In addition, in this specification, the glass transition temperature (Tg) of a polymer (resin) is a value measured by the method described in Examples as described later.

[0164] The content ratio of the above three structural units constituting polyvinyl butyral can be arbitrarily adjusted according to desired physical properties.

[0165] Polyvinyl butyral may have structural units other than the above three structural units. 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 polyvinyl butyral.

[0166] Acrylic resin

[0167] Examples of the acrylic resin include known acrylic polymers.

[0168] The weight average molecular weight (Mw) of the acrylic resin is preferably 10,000 to 2,000,000, more preferably 100,000 to 1,500,000.

[0169] By setting the weight average molecular weight of the acrylic resin to be greater than or equal to the aforementioned lower limit, the shape stability (temporal stability during storage) of the thermosetting resin film (x1) can be easily improved. Furthermore, by setting the weight average molecular weight of the acrylic resin to be less than or equal to the aforementioned upper limit, the thermosetting resin film (x1) can easily follow the uneven surface of the adherend, and, for example, the formation of voids between the adherend and the thermosetting resin film (x1) can be easily suppressed.

[0170] The glass transition temperature (Tg) of the acrylic resin is preferably -60 to 70°C, more preferably -30 to 50°C.

[0171] By setting the glass transition temperature (Tg) of the acrylic resin to be above the aforementioned lower limit, the adhesive force between the protective film (X) and the support sheet (Y) is suppressed, thereby improving the releasability of the support sheet (Y). Furthermore, by setting the glass transition temperature (Tg) of the acrylic resin to be below the aforementioned upper limit, the adhesive force between the thermosetting resin film (x1) and the protective film (X) to the adherend is improved.

[0172] Examples of acrylic resins include polymers of one or more (meth)acrylates; and copolymers of two or more monomers selected from (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, and N-methylolacrylamide.

[0173] Examples of the (meth)acrylates 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 isononyl (meth)acrylate. (Meth)acrylate alkyl esters wherein the alkyl group constituting the alkyl ester is a chain structure having 1 to 18 carbon atoms, such as 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);

[0174] Cycloalkyl (meth)acrylates such as isobornyl (meth)acrylate and dicyclopentyl (meth)acrylate;

[0175] Aralkyl (meth)acrylates such as benzyl (meth)acrylate;

[0176] Cycloalkenyl (meth)acrylates such as dicyclopentenyl (meth)acrylate;

[0177] Cycloalkenyloxyalkyl (meth)acrylates such as dicyclopentenyloxyethyl (meth)acrylate;

[0178] (Meth)acrylimide;

[0179] Glycidyl (meth)acrylates such as glycidyl (meth)acrylate;

[0180] (Meth)acrylates containing a hydroxy group, 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;

[0181] (Meth)acrylates containing a substituted amino group, such as N-methylaminoethyl (meth)acrylate, and the like.

[0182] In the present specification, a "substituted amino group" refers to a group in which one or two hydrogen atoms of an amino group are substituted with a group other than a hydrogen atom.

[0183] The acrylic resin may be obtained by copolymerizing one or more monomers selected from (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, and N-methylolacrylamide, in addition to (meth)acrylate.

[0184] The monomers constituting the acrylic resin may be a single species or two or more species. When the monomers constituting the acrylic resin are two or more species, their combination and ratio may be arbitrarily selected.

[0185] 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, and an isocyanate group.

[0186] The functional groups of the acrylic resin may be bonded to other compounds via a crosslinking agent (F) described below, or may be directly bonded to other compounds without the crosslinking agent (F). By utilizing the functional groups to bond the acrylic resin to other compounds, the reliability of the package obtained using the thermosetting resin film (x1) tends to be improved.

[0187] Other resins

[0188] Here, in one embodiment of the present invention, as the polymer component (A), polyvinyl acetal and a thermoplastic resin other than an acrylic resin (hereinafter sometimes simply referred to as "thermoplastic resin") may be used alone instead of an acrylic resin, or polyvinyl acetal and / or an acrylic resin may be used in combination.

[0189] By using a thermoplastic resin, the peelability of the protective film (X) from the support sheet (Y) is sometimes improved, the thermosetting resin film (x1) can easily follow the uneven surface of the adherend, and the formation of gaps between the adherend and the thermosetting resin film (x1) is suppressed.

[0190] The weight average molecular weight of the thermoplastic resin is preferably 1,000 to 100,000, more preferably 3,000 to 80,000.

[0191] The glass transition temperature (Tg) of the thermoplastic resin is preferably -30 to 150°C, more preferably -20 to 120°C.

[0192] Examples of the thermoplastic resin include polyester, polyurethane, phenoxy resin, polybutene, polybutadiene, and polystyrene.

[0193] Thermoplastic resins may be used alone or in combination of two or more. When two or more thermoplastic resins are used, their combination and ratio may be arbitrarily selected.

[0194] Content of polymer component (A)

[0195] From the viewpoint of easily obtaining a protective film (X) satisfying the requirements (β1) and (β2), the content of the polymer component (A) is preferably 5 to 85% by mass, more preferably 10 to 80% by mass, further preferably 15 to 70% by mass, further preferably 15 to 60% by mass, further preferably 15 to 50% by mass, based on the total amount of the active ingredients of the thermosetting resin composition (x1-1).

[0196] Preferred aspects of polymer component (A)

[0197] As described above, the polymer component (A) is preferably at least one selected from polyvinyl acetal and acrylic resin. From the viewpoint of more easily obtaining a protective film (X) satisfying the requirements (β1) and (β2), the polymer component (A) is preferably polyvinyl acetal.

[0198] It should be noted that the polymer component (A) may also be a thermosetting component (B). In the present invention, when the thermosetting resin composition (x1-1) contains components belonging to both the polymer component (A) and the thermosetting component (B), the thermosetting resin composition (x1-1) is deemed to contain both the polymer component (A) and the thermosetting component (B).

[0199] (Thermosetting component (B))

[0200] The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) contain a thermosetting component (B).

[0201] The thermosetting component (B) is a component for curing the thermosetting resin film (x1) to form a hard protective film (X).

[0202] The thermosetting component (B) may be used alone or in combination of two or more. When two or more thermosetting components (B) are used, their combination and ratio may be arbitrarily selected.

[0203] Examples of the thermosetting component (B) include epoxy-based thermosetting resins, thermosetting polyimides, polyurethanes, unsaturated polyesters, and silicone resins, among which epoxy-based thermosetting resins are preferred.

[0204] The epoxy thermosetting resin comprises an epoxy resin (B1) and a thermosetting agent (B2).

[0205] The epoxy thermosetting resin may be used alone or in combination of two or more. When two or more epoxy thermosetting resins are used, their combination and ratio may be arbitrarily selected.

[0206] Epoxy resin (B1)

[0207] Examples of the epoxy resin (B1) include known epoxy resins, such as polyfunctional epoxy resins, biphenyl compounds, bisphenol A diglycidyl ether and hydrogenated products thereof, o-cresol novolac epoxy resins, dicyclopentadiene epoxy resins, biphenyl epoxy resins, bisphenol A epoxy resins, bisphenol F epoxy resins, phenylene skeleton epoxy resins, and epoxy compounds having two or more functional groups.

[0208] Epoxy resins having unsaturated hydrocarbon groups can also be used as epoxy resins (B1). Epoxy resins having unsaturated hydrocarbon groups have higher compatibility with acrylic resins than epoxy resins without unsaturated hydrocarbon groups. Therefore, the use of epoxy resins having unsaturated hydrocarbon groups improves the reliability of the package obtained using the thermosetting resin film (x1).

[0209] Examples of epoxy resins having unsaturated hydrocarbon groups include compounds in which a portion of the epoxy groups of a polyfunctional epoxy resin has been converted to groups having unsaturated hydrocarbon groups. Such compounds can be obtained, for example, by an addition reaction of (meth)acrylic acid or its derivatives with epoxy groups. Examples of epoxy resins having unsaturated hydrocarbon groups include compounds in which groups having unsaturated hydrocarbon groups are directly bonded to aromatic rings, etc., constituting the epoxy resin.

[0210] The unsaturated hydrocarbon group is a polymerizable unsaturated group, and specific examples thereof include vinyl group (vinyl group, ethenyl group), 2-propenyl group (allyl group), (meth)acryloyl group, and (meth)acrylamide group, etc. Among them, acryloyl group is preferred.

[0211] The number average molecular weight of the epoxy resin (B1) is not particularly limited, but is preferably 300 to 30,000, more preferably 400 to 10,000, and even more preferably 500 to 3,000, from the viewpoint of the curability of the thermosetting resin film (x1) and the strength and heat resistance of the protective film (X) after curing.

[0212] The epoxy equivalent of the epoxy resin (B1) is preferably 100 to 1000 g / eq, more preferably 300 to 800 g / eq.

[0213] 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 may be arbitrarily selected.

[0214] Thermal curing agent (B2)

[0215] The thermosetting agent (B2) functions as a curing agent for the epoxy resin (B1).

[0216] Examples of the thermosetting agent (B2) include compounds having two or more functional groups capable of reacting with epoxy groups in one molecule. Examples of such functional groups include phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, carboxyl groups, and groups formed by acid anhydride reaction of acid groups. Phenolic hydroxyl groups, amino groups, or groups formed by acid anhydride reaction of acid groups are preferred, and phenolic hydroxyl groups or amino groups are more preferred.

[0217] Examples of the phenolic curing agent having a phenolic hydroxyl group in the thermosetting agent (B2) include polyfunctional phenolic resins, biphenols, novolac-type phenolic resins, dicyclopentadiene-based phenolic resins, and aralkylphenolic resins.

[0218] Examples of the amine curing agent having an amino group in the thermosetting agent (B2) include dicyandiamide (hereinafter, sometimes simply referred to as "DICY") and the like.

[0219] The heat curing agent (B2) may be a heat curing agent having an unsaturated hydrocarbon group.

[0220] Examples of the thermosetting agent (B2) having an unsaturated hydrocarbon group include compounds in which a portion of the hydroxyl groups of a phenolic resin are substituted with a group having an unsaturated hydrocarbon group, and compounds in which a group having an unsaturated hydrocarbon group is directly bonded to the 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.

[0221] When a phenolic curing agent is used as the thermosetting agent (B2), the thermosetting agent (B2) is preferably one having a high softening point or glass transition temperature from the viewpoint of easily improving the releasability of the protective film (X) from the support sheet (Y).

[0222] The number average molecular weight of the resin component in the thermosetting agent (B2), such as a polyfunctional phenolic resin, a novolac phenolic resin, a dicyclopentadiene phenolic resin, and an aralkylphenolic resin, is preferably 300 to 30,000, more preferably 400 to 10,000, and even more preferably 500 to 3,000.

[0223] The molecular weight of non-resin components such as biphenol and dicyandiamide in the thermosetting agent (B2) is not particularly limited, but is preferably 60 to 500, for example.

[0224] The thermosetting agent (B2) may be used alone or in combination of two or more. When two or more thermosetting agents (B2) are used, their combination and ratio may be arbitrarily selected.

[0225] In the thermosetting resin composition (x1-1), the content of the thermosetting agent (B2) is preferably 0.1 to 500 parts by mass, more preferably 1 to 200 parts by mass, relative to 100 parts by mass of the epoxy resin (B1). By making the content of the thermosetting agent (B2) greater than or equal to the above lower limit, curing of the thermosetting resin film (x1) is more easily performed. In addition, by making the content of the thermosetting agent (B2) less than or equal to 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.

[0226] In the thermosetting resin composition (x1-1), the content of the thermosetting component (B) (the total content of the epoxy resin (B1) and the thermosetting agent (B2)) is preferably 50 to 1000 parts by mass, more preferably 70 to 800 parts by mass, further preferably 80 to 600 parts by mass, further preferably 90 to 500 parts by mass, further preferably 100 to 400 parts by mass relative to 100 parts by mass of the content of the polymer component (A). By making the content of the thermosetting component (B) such a range, the adhesion between the protective film (X) and the support sheet (Y) is suppressed, and the peelability of the support sheet (Y) is improved. In addition, it is easy to obtain a protective film (X) that meets the requirements (β1) and (β2). It should be noted that the more the amount of the thermosetting component (B) relative to the polymer component (A) is increased, the easier it is to increase the tensile modulus E'. On the contrary, the tensile modulus E' tends to decrease as the amount of the thermosetting component (B) relative to the polymer component (A) decreases.

[0227] (Curing accelerator (C))

[0228] The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a curing accelerator (C).

[0229] The curing accelerator (C) is a component for adjusting the curing speed of the thermosetting resin composition (x1-1).

[0230] Preferred curing accelerators (C) include, for example, tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles (imidazoles in which one or more hydrogen atoms are replaced by 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 replaced by organic groups) such as tributylphosphine, diphenylphosphine, and triphenylphosphine; tetraphenylphosphine; Tetraphenylborate, triphenylphosphine tetraphenylborate and other tetraphenylborate, etc.

[0231] The curing accelerator (C) may be used alone or in combination of two or more. When two or more curing accelerators (C) are used, their combination and ratio may be arbitrarily selected.

[0232] In the thermosetting resin composition (x1-1), the content of the curing accelerator (C) when using the curing accelerator (C) is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass relative to 100 parts by mass of the content of the thermosetting component (B). By making the content of the curing accelerator (C) above the above lower limit, it is easy to more significantly obtain the effect brought about by the use of the curing accelerator (C). In addition, by making the content of the curing accelerator (C) below the above upper limit, for example, the effect of suppressing the high-polarity curing accelerator (C) from moving to the bonding interface side with the adherend in the thermosetting resin film (x1) under high temperature / high humidity conditions and segregating is increased, and the reliability of the package obtained using the thermosetting resin film (x1) is further improved.

[0233] (Filling material (D))

[0234] The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a filler (D).

[0235] By including the filler (D), the thermal expansion coefficient of the protective film (X) obtained by curing the curable resin film (x1) can be easily adjusted to an appropriate range, thereby further improving the reliability of the package obtained using the thermosetting resin film (x1). In addition, by including the filler (D) in the thermosetting resin film (x1), the moisture absorption rate of the protective film (X) can be reduced, thereby improving heat dissipation.

[0236] The filler (D) may be any of an organic filler and an inorganic filler, but is preferably an inorganic filler. Preferred inorganic fillers include, for example, powders of silica, alumina, talc, calcium carbonate, titanium dioxide, iron oxide red, silicon carbide, and boron nitride; spherical beads of these inorganic fillers; surface-modified products of these inorganic fillers; single crystal fibers of these inorganic fillers; and glass fibers.

[0237] The filler (D) may be used alone or in combination of two or more.

[0238] When there are two or more fillers (D), their combination and ratio can be arbitrarily selected.

[0239] When a filler (D) is used, the content of the filler (D) is preferably 5 to 80% by mass, more preferably 7 to 60% by mass, based on the total amount of the active ingredients of the thermosetting resin composition (x1-1). By setting the content of the filler (D) within this range, the above-mentioned thermal expansion coefficient can be more easily adjusted.

[0240] The average particle size of the filler (D) is preferably 5 nm to 1000 nm, more preferably 5 nm to 500 nm, and even more preferably 10 nm to 300 nm. The above average particle size is obtained by measuring the outer diameter of one particle at multiple locations and averaging the measured values.

[0241] (Coupling agent (E))

[0242] The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a coupling agent (E).

[0243] By using a coupling agent (E) having a functional group capable of reacting with an inorganic compound or an organic compound, the adhesion and tightness of the thermosetting resin film (x1) to the adherend can be easily improved. In addition, by using a coupling agent (E), the protective film (X) obtained by curing the thermosetting resin film (x1) can be easily improved in water resistance without compromising heat resistance.

[0244] The coupling agent (E) is preferably a compound having a functional group capable of reacting with the functional groups possessed by the polymer component (A) and the thermosetting component (B), and is more preferably a silane coupling agent. Preferred silane coupling agents include, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxymethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3- -(2-aminoethylamino)propylmethyldiethoxysilane, 3-(phenylamino)propyltrimethoxysilane, 3-anilinopropyltrimethoxysilane, 3-ureapropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfide, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazole silane, etc.

[0245] The coupling agent (E) may be used alone or in combination of two or more. When two or more coupling agents (E) are used, their combination and ratio may be arbitrarily selected.

[0246] In the thermosetting resin composition (x1-1), when a coupling agent (E) is used, 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 relative to 100 parts by mass of the total content of the polymer component (A) and the thermosetting component (B). By making the content of the coupling agent (E) greater than or equal to the above lower limit, the effects of using the coupling agent (E), such as improved dispersibility of the filler (D) in the resin and improved adhesion between the thermosetting resin film (x1) and the adherend, can be more significantly achieved. In addition, by making the content of the coupling agent (E) less than or equal to the above upper limit, the occurrence of outgassing can be further suppressed.

[0247] (Crosslinking agent (F))

[0248] When using as the polymer component (A) a component having a functional group such as a vinyl group, a (meth)acryloyl group, an amino group, a hydroxyl group, a carboxyl group or an isocyanate group that can bond with other compounds, the thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a crosslinking agent (F) for bonding the above-mentioned functional groups with other compounds to perform crosslinking.

[0249] By cross-linking using the cross-linking agent (F), the initial adhesive force and cohesive force of the thermosetting resin film (x1) can be adjusted.

[0250] Examples of the crosslinking agent (F) include organic polyisocyanate compounds, organic polyimine compounds, metal chelate crosslinking agents (crosslinking agents having a metal chelate structure), and aziridine crosslinking agents (crosslinking agents having an aziridine group).

[0251] 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 these aromatic polyisocyanate compounds, etc.; and isocyanate-terminated urethane prepolymers obtained by reacting these aromatic polyisocyanate compounds, etc., with polyol compounds. The "adducts" mentioned above refer to reaction products of the aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, or alicyclic polyisocyanate compounds with low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, or castor oil. Examples thereof include xylylene diisocyanate adducts of trimethylolpropane.

[0252] More specifically, the organic polyisocyanate compound includes, for example, 2,4-toluene diisocyanate; 2,6-toluene diisocyanate; 1,3-xylylene diisocyanate; 1,4-xylene diisocyanate; diphenylmethane-4,4'-diisocyanate; diphenylmethane-2,4'-diisocyanate; 3-methyldiphenylmethane diisocyanate; hexamethylene diisocyanate; isophorone diisocyanate; dicyclohexylmethane-4,4'-diisocyanate; dicyclohexylmethane-2,4'-diisocyanate; a compound in which one or more of toluene diisocyanate, hexamethylene diisocyanate and xylylene diisocyanate are added to all or part of the hydroxyl groups of a polyol such as trimethylolpropane; lysine diisocyanate, etc.

[0253] Examples of the organic polyimine compound include N,N′-diphenylmethane-4,4′-bis(1-aziridinecarboxamide), trimethylolpropane-tris-β-aziridinylpropionate, tetramethylolmethane-tris-β-aziridinylpropionate, and N,N′-toluene-2,4-bis(1-aziridinecarboxamide)triethylenemelamine.

[0254] When an organic polyisocyanate compound is used as the crosslinking agent (F), a hydroxyl-containing polymer is preferably used 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).

[0255] The crosslinking agent (F) may be used alone or in combination of two or more. When two or more crosslinking agents (F) are used, their combination and ratio may be arbitrarily selected.

[0256] In the thermosetting resin composition (x1-1), when a crosslinking agent (F) is used, 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 relative to 100 parts by mass of the polymer component (A). By setting the content of the crosslinking agent (F) to be greater than the lower limit, the effect of using the crosslinking agent (F) can be more significantly achieved. In addition, by setting the content of the crosslinking agent (F) to be less than the upper limit, excessive use of the crosslinking agent (F) can be suppressed.

[0257] (Energy ray curable resin (G))

[0258] The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain an energy ray-curable resin (G).

[0259] The thermosetting resin film (x1) can change its properties by being irradiated with energy rays by containing the energy ray curable resin (G).

[0260] The energy ray curable resin (G) is a resin 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, preferably acrylate compounds having a (meth)acryloyl group.

[0261] Examples of the acrylate compound include (meth)acrylates containing a chain aliphatic skeleton, 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-butanediol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate; (meth)acrylates containing a cyclic aliphatic skeleton, 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.

[0262] The weight average molecular weight of the energy ray-curable compound is preferably 100 to 30,000, more preferably 300 to 10,000.

[0263] 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, their combination and ratio may be arbitrarily selected.

[0264] When the energy ray curable resin (G) is used, the content of the energy ray curable resin (G) is preferably 1 to 95% by mass, more preferably 5 to 90% by mass, and even more preferably 10 to 85% by mass based on the total amount of the active ingredients in the thermosetting resin composition (x1-1).

[0265] (Photopolymerization initiator (H))

[0266] 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 carry out the polymerization reaction of the energy ray-curable resin (G).

[0267] Specific examples of the photopolymerization initiator (H) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoylbenzoic acid, methyl benzoylbenzoate, benzoin dimethyl ether, 2,4-diethylthiazolone, 1-hydroxycyclohexylphenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzil, bibenzyl, diacetyl, 1,2-diphenylmethane, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and 2-chloroanthraquinone.

[0268] The photopolymerization initiator (H) may be used alone or in combination of two or more. When two or more photopolymerization initiators (H) are used, their combination and ratio may be arbitrarily selected.

[0269] 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 based on 100 parts by mass of the energy ray-curable resin (G).

[0270] (General Additive (I))

[0271] The thermosetting resin film (x1) and the thermosetting resin composition (x1-1) may contain a general-purpose additive (I) within a range not impairing the effects of the present invention. The general-purpose additive (I) may be a known one and may be arbitrarily selected according to the purpose without particular limitation.

[0272] Preferred general additives (I) include, for example, plasticizers, antistatic agents, antioxidants, colorants (dyes, pigments), and getters.

[0273] The general-purpose additive (I) may be used alone or in combination of two or more. When two or more general-purpose additives (I) are used, their combination and ratio may be arbitrarily selected.

[0274] The content of the general-purpose additive (I) is not particularly limited and can be appropriately selected depending on the intended purpose.

[0275] (Solvent)

[0276] The thermosetting resin composition (x1-1) preferably further contains a solvent.

[0277] The thermosetting resin composition (x1-1) containing a solvent has good handleability.

[0278] The solvent is not particularly limited, and preferred solvents include, for example, hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, 2-propanol, isobutanol (2-methylpropane-1-ol), and 1-butanol; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; amides (compounds having an amide bond) such as dimethylformamide and N-methylpyrrolidone, etc.

[0279] The solvent may be used alone or in combination of two or more. When two or more solvents are used, their combination and ratio may be arbitrarily selected.

[0280] From the viewpoint of being able to more uniformly mix the components contained in the thermosetting resin composition (x1-1), the solvent is preferably methyl ethyl ketone or the like.

[0281] (Preparation method of thermosetting resin composition (x1-1))

[0282] The thermosetting resin composition (x1-1) can be prepared by blending the components constituting the thermosetting resin composition (x1-1).

[0283] The order of addition of the components 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 other components to dilute the components before use, or the solvent may be mixed with the components without diluting them before use.

[0284] The method for mixing the components during compounding is not particularly limited and may be appropriately selected from known methods such as a method of mixing by rotating a stirring bar or a stirring blade, a method of mixing using a mixer, and a method of mixing by applying ultrasonic waves.

[0285] The temperature and time during addition and mixing of the components are not particularly limited as long as they do not deteriorate the components and may be adjusted appropriately. However, the temperature is preferably 15 to 30°C.

[0286] Energy ray curable resin film (x2)

[0287] The energy ray curable resin film (x2) contains an energy ray curable component (a).

[0288] The energy ray curable resin film (x2) is formed of, for example, an energy ray curable resin composition (x2-1) containing an energy ray curable component (a).

[0289] The energy ray-curable component (a) is preferably uncured and preferably has adhesiveness, and more preferably is uncured and has adhesiveness.

[0290] It should be noted that in the following description of this specification, "the content of each component based on the total amount of effective ingredients of the energy ray-curable resin composition (x2-1)" and "the content of each component of the energy ray-curable resin film (x2) formed by the energy ray-curable resin composition (x2-1)" have the same meaning.

[0291] (Energy ray curable component (a))

[0292] The energy ray curable component (a) is a component that is cured by irradiation with energy rays, and is also a component for imparting film-forming properties, flexibility, and the like to the energy ray curable resin film (x2).

[0293] 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 be an uncrosslinked polymer.

[0294] (Polymer (a1))

[0295] 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 above-mentioned functional group and an energy ray-curable group such as an energy ray-curable double bond.

[0296] 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 replaced by groups other than hydrogen atoms), and epoxy groups. From the perspective of preventing corrosion of circuits such as semiconductor wafers and semiconductor chips, the functional groups are preferably groups other than carboxyl groups. Among these, the functional groups are preferably hydroxyl groups.

[0297] Acrylic polymer with functional group (a11)

[0298] Examples of the acrylic polymer (a11) having a functional group include polymers obtained by copolymerizing an acrylic monomer having a functional group with an acrylic monomer not having a functional group. In addition to these monomers, a monomer other than the acrylic monomer (non-acrylic monomer) may be further copolymerized. The acrylic polymer (a11) may be a random copolymer or a block copolymer.

[0299] Examples of the acrylic monomer having a functional group include a hydroxyl group-containing monomer, a carboxyl group-containing monomer, an amino group-containing monomer, a substituted amino group-containing monomer, and an epoxy group-containing monomer.

[0300] Examples of the hydroxyl group-containing monomer 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 that do not have a (meth)acryloyl skeleton) such as vinyl alcohol and allyl alcohol.

[0301] Examples of carboxyl group-containing monomers include: ethylenically unsaturated monocarboxylic acids (monocarboxylic acids having an ethylenically unsaturated bond) such as (meth)acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids (dicarboxylic acids having an ethylenically unsaturated bond) such as fumaric acid, itaconic acid, maleic acid, and citraconic acid; anhydrides of the above-mentioned ethylenically unsaturated dicarboxylic acids; (meth)acrylic acid carboxylalkyl esters such as 2-carboxyethyl methacrylate, and the like.

[0302] 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.

[0303] The acrylic monomer having a functional group constituting the acrylic polymer (a11) may be used alone or in combination of two or more. When two or more acrylic monomers having a functional group constituting the acrylic polymer (a11) are used, their combination and ratio may be arbitrarily selected.

[0304] 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, isononyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. (Meth)acrylate alkyl esters having a chain structure of 1 to 18 carbon atoms, such as 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).

[0305] Examples of acrylic monomers having a functional group include: (meth)acrylates containing alkoxyalkyl groups such as methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and ethoxyethyl (meth)acrylate; (meth)acrylates containing aromatic groups such as aryl (meth)acrylates such as phenyl (meth)acrylate; non-crosslinking (meth)acrylamide and its derivatives; and non-crosslinking (meth)acrylates containing tertiary amino groups such as N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate.

[0306] The acrylic monomer having no functional group constituting the acrylic polymer (a11) may be used alone or in combination of two or more. When two or more acrylic monomers having no functional group constituting the acrylic polymer (a11) are used, their combination and ratio may be arbitrarily selected.

[0307] Examples of the non-acrylic monomer include olefins such as ethylene and norbornene; vinyl acetate; and styrene.

[0308] The non-acrylic monomer constituting the acrylic polymer (a11) may be used alone or in combination of two or more. When two or more non-acrylic monomers are used to constitute the acrylic polymer (a11), their combination and ratio may be arbitrarily selected.

[0309] In the acrylic polymer (a11), the ratio (content) of the structural units derived from the 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% by mass, more preferably 1 to 40% by mass, and even more preferably 3 to 30% by mass. By setting the ratio within this range, the content of the energy ray-curable group in the acrylic resin (a1-1) obtained by copolymerizing the acrylic polymer (a11) and the energy ray-curable compound (a12) can be easily adjusted to a preferred range for the degree of curing of the protective film (X).

[0310] The acrylic polymer (a11) constituting the acrylic resin (a1-1) may be used alone or in combination of two or more. When two or more acrylic polymers (a11) are used to constitute the acrylic resin (a1-1), their combination and ratio may be arbitrarily selected.

[0311] The content of the acrylic resin (a1-1) is preferably 1 to 60% by mass, more preferably 3 to 50% by mass, and even more preferably 5 to 40% by mass based on the total amount of the active ingredients in the energy ray-curable resin composition (x2-1).

[0312] Energy ray curable compound (a12)

[0313] The energy ray-curable compound (a12) preferably has one or more selected from an isocyanate group, an epoxy group, and a carboxyl group as a group capable of reacting with the functional group of the acrylic polymer (a11), and more preferably has an isocyanate group as the above group.

[0314] When the energy ray-curable compound (a12) has an isocyanate group as the group, for example, the isocyanate group easily reacts with the hydroxyl group of the acrylic polymer (a11) having a hydroxyl group as the functional group.

[0315] The energy ray curable compound (a12) preferably has 1 to 5 energy ray curable groups in one molecule, and more preferably has 1 to 2 energy ray curable groups.

[0316] Examples of the energy ray-curable compound (a12) include 2-methacryloyloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, and 1,1-(bisacryloyloxymethyl)ethyl isocyanate; acryloyl monoisocyanate compounds obtained by reacting a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate; and acryloyl monoisocyanate compounds obtained by reacting a diisocyanate compound or a polyisocyanate compound, a polyol compound, and hydroxyethyl (meth)acrylate. Among these, the energy ray-curable compound (a12) is preferably 2-methacryloyloxyethyl isocyanate.

[0317] The energy ray curable compound (a12) constituting the acrylic resin (a1-1) may be used alone or in combination of two or more. When two or more energy ray curable compounds (a12) are used to constitute the acrylic resin (a1-1), their combination and ratio may be arbitrarily selected.

[0318] In acrylic resin (a1-1), relative to the content of the above-mentioned functional groups derived from acrylic polymer (a11), the ratio of the content of the energy ray curable group derived from energy ray curable compound (a12) is preferably 20 to 120 mol%, more preferably 35 to 100 mol%, and further preferably 50 to 100 mol%. By making the ratio of the above-mentioned content such a range, the adhesive force of the protective film (X) after curing becomes greater. It should be noted that, when the energy ray curable compound (a12) is a monofunctional (having one of the above-mentioned groups in one molecule) compound, the upper limit of the ratio of the above-mentioned content is 100 mol%, and when the energy ray curable compound (a12) is a polyfunctional (having two or more of the above-mentioned groups in one molecule) compound, the upper limit of the ratio of the above-mentioned content exceeds 100 mol%.

[0319] The weight average molecular weight (Mw) of the polymer (a1) is preferably 100,000 to 2,000,000, more preferably 300,000 to 1,500,000.

[0320] In the case where the polymer (a1) is a polymer at least a portion of which is cross-linked by a cross-linking agent, the polymer (a1) may be a polymer obtained by polymerizing the following monomers and cross-linking in the group that reacts with the above-mentioned cross-linking agent, wherein the monomer is a monomer that does not belong to any of the above-mentioned monomers and has a group that reacts with the cross-linking agent and is described as a monomer constituting the acrylic polymer (a11), and the polymer (a1) may also be a polymer derived from an energy line-curable compound (a12) and cross-linked in the group that reacts with the above-mentioned functional group.

[0321] The polymer (a1) may be used alone or in combination of two or more. When two or more polymers (a1) are used, their combination and ratio may be arbitrarily selected.

[0322] (Compound (a2))

[0323] Examples of the energy ray curable group of the compound (a2) having an energy ray curable group and a weight average molecular weight of 100 to 80,000 include groups containing energy ray curable double bonds, and preferred groups include (meth)acryloyl groups and vinyl groups.

[0324] The compound (a2) is not particularly limited as long as it satisfies the above conditions, and examples thereof include low molecular weight compounds having energy ray curable groups, epoxy resins having energy ray curable groups, and phenolic resins having energy ray curable groups.

[0325] Among the compounds (a2), examples of low molecular weight compounds having energy line curable groups include multifunctional monomers or oligomers, and preferably acrylate compounds having (meth) acryloyl groups. Examples of 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) acryloyloxypolyethoxy) phenyl] propane, ethoxylated bisphenol A di(meth) acrylate, 2,2-bis[4-((meth) acryloyloxydiethoxy) phenyl] propane, 9,9-bis[4-(2-(meth) acryloyloxyethyl] methacrylate. [((meth)acryloyloxy)phenyl]fluorene, 2,2-bis[4-((meth)acryloyloxypolypropoxy)phenyl]propane, tricyclodecane dimethanol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate difunctional (meth)acrylates such as acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 2,2-bis[4-((meth)acryloyloxyethoxy)phenyl]propane, neopentyl glycol di(meth)acrylate, ethoxylated polypropylene glycol di(meth)acrylate, 2-hydroxy-1,3-di(meth)acryloyloxypropane; tri(2-(meth)acryloyloxyethyl)isocyanurate, ε-caprolactone-modified tri-(2-(meth)acryloyloxyethyl)isocyanurate Polyfunctional (meth)acrylates such as urate, ethoxylated glycerol 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.

[0326] Among the compounds (a2), examples of the epoxy resin having an energy ray-curable group and the phenol resin having an energy ray-curable group include those described in paragraph 0043 of JP-A-2013-194102.

[0327] The weight average molecular weight of the compound (a2) is preferably 100 to 30,000, more preferably 300 to 10,000.

[0328] The compound (a2) may be used alone or in combination of two or more. When two or more compounds (a2) are used, their combination and ratio may be arbitrarily selected.

[0329] (Polymer (b) Not Having an Energy Ray-Curable Group)

[0330] 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) having no energy ray-curable group.

[0331] The polymer (b) having no energy ray-curable group may be a polymer at least part of which is cross-linked by a cross-linking agent, or may be an uncross-linked polymer.

[0332] Examples of the polymer (b) not having an energy ray-curable group include acrylic polymers, phenoxy resins, urethane resins, polyesters, rubber resins, and acrylic urethane resins. Among these, the polymer (b) is preferably an acrylic polymer (hereinafter sometimes referred to as "acrylic polymer (b-1)").

[0333] 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. Furthermore, the acrylic polymer (b-1) may be a copolymer of one or more acrylic monomers and one or more monomers other than acrylic monomers (non-acrylic monomers).

[0334] Examples of the acrylic monomer constituting the acrylic polymer (b-1) include alkyl (meth)acrylates, (meth)acrylates having a cyclic skeleton, glycidyl group-containing (meth)acrylates, hydroxyl group-containing (meth)acrylates, and substituted amino group-containing (meth)acrylates.

[0335] Examples of the alkyl (meth)acrylate 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, isononyl (meth)acrylate, and (meth)acrylate. (Meth)acrylate alkyl esters such as 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) are chain structures having 1 to 18 carbon atoms.

[0336] Examples of the (meth)acrylate having a cyclic skeleton include cycloalkyl (meth)acrylates such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; cycloalkenyl (meth)acrylates such as dicyclopentenyl (meth)acrylate; and cycloalkenyloxyalkyl (meth)acrylates such as dicyclopentenyloxyethyl (meth)acrylate.

[0337] Examples of the glycidyl group-containing (meth)acrylate include glycidyl (meth)acrylate, etc. Examples of the hydroxyl group-containing (meth)acrylate 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.

[0338] Examples of the substituted amino group-containing (meth)acrylate include N-methylaminoethyl (meth)acrylate.

[0339] Examples of the non-acrylic monomer constituting the acrylic polymer (b-1) include olefins such as ethylene and norbornene; vinyl acetate; and styrene.

[0340] Examples of the polymer (b) having no energy ray-curable group and at least partially cross-linked by a cross-linking agent include polymers obtained by reacting a reactive functional group in the polymer (b) with a cross-linking agent.

[0341] The reactive functional group can be appropriately selected according to the type of cross-linking agent, and is not particularly limited. For example, when the cross-linking agent is a polyisocyanate compound, examples of the reactive functional group include hydroxyl, carboxyl, and amino groups, among which hydroxyl groups having high reactivity with isocyanate groups are preferred.

[0342] When the crosslinking agent is an epoxy compound, examples of the reactive functional group include a carboxyl group, an amino group, and an amide group. Among them, a carboxyl group having high reactivity with an epoxy group is preferred.

[0343] Among them, from the viewpoint of preventing circuit corrosion of a semiconductor wafer or semiconductor chip, the reactive functional group is preferably a group other than a carboxyl group.

[0344] As polymers (b) having reactive functional groups but not having energy ray-curable groups, for example, polymers obtained by polymerizing monomers having at least reactive functional groups can be mentioned. In the case of acrylic polymers (b-1), any one or both of the acrylic monomers and non-acrylic monomers listed as monomers constituting the same may be monomers having reactive functional groups. For example, as polymers (b) having hydroxyl groups as reactive functional groups, for example, polymers obtained by polymerizing hydroxyl-containing (meth)acrylates can be mentioned. In addition, polymers obtained by polymerizing monomers in which one or two or more hydrogen atoms in the acrylic monomers or non-acrylic monomers listed above are replaced by the reactive functional groups can be mentioned.

[0345] In the polymer (b) having a reactive functional group, the ratio (content) of the amount of the structural unit 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% by mass, more preferably 2 to 10% by mass. When the ratio falls within this range, the degree of crosslinking in the polymer (b) falls within a more preferred range.

[0346] From the viewpoint of further improving the film-forming property of the energy ray-curable resin composition (x2-1), the weight average molecular weight (Mw) of the polymer (b) having no energy ray-curable group is preferably 10,000 to 2,000,000, more preferably 100,000 to 1,500,000.

[0347] The polymer (b) not having an energy ray curable group may be used alone or in combination of two or more. When two or more polymers (b) not having an energy ray curable group are used, their combination and ratio may be arbitrarily selected.

[0348] Examples of the energy ray-curable resin composition (x2-1) include compositions containing either or both of the polymer (a1) and the compound (a2).

[0349] Among these, when the energy ray-curable resin composition (x2-1) contains the compound (a2), it is preferred to further contain a polymer (b) having no energy ray-curable group. In this case, it is preferred to further contain the polymer (a1).

[0350] Moreover, the energy ray-curable resin composition (x2-1) may contain not the compound (a2) but the polymer (a1) and the polymer (b) having no energy ray-curable group.

[0351] When the energy ray-curable resin composition (x2-1) contains a polymer (a1), a compound (a2), and a 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, relative to 100 parts by mass of the total content of the polymer (a1) and the polymer (b) having no energy ray-curable group.

[0352] 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% by mass, more preferably 10 to 80% by mass, and even more preferably 20 to 70% by mass, based on the total amount of active ingredients in the energy ray-curable resin composition (x2-1). By setting the content of the energy ray-curable component within this range, the energy ray curability of the energy ray-curable resin film (x2) becomes even better.

[0353] The energy ray-curable resin composition (x2-1) may contain, in addition to the energy ray-curable component, one or more selected from thermosetting components, photopolymerization initiators, fillers, coupling agents, crosslinking agents, and general additives depending on the purpose.

[0354] For example, by using an energy ray-curable resin composition (x2-1) containing an energy ray-curable component and a thermosetting component, the formed energy ray-curable resin film (x2) has improved adhesion to the adherend by heating, and the strength of the protective film (X) formed by the energy ray-curable resin film (x2) is also improved.

[0355] As the thermosetting component, photopolymerization initiator, filler, coupling agent, crosslinker and general additive in the energy ray-curable resin composition (x2-1), the same substances as the thermosetting component (B), photopolymerization initiator (H), filler (D), coupling agent (E), crosslinker (F) and general additive (I) in the energy ray-curable resin composition (x2-1) can be listed respectively.

[0356] In the energy ray-curable resin composition (x2-1), the thermosetting component, photopolymerization initiator, filler, coupling agent, crosslinking agent, and general additive may be used alone or in combination of two or more. When two or more are used in combination, their combination and ratio may be arbitrarily selected.

[0357] The contents of the thermosetting component, photopolymerization initiator, filler, coupling agent, crosslinking agent, and general additives in the energy ray-curable resin composition (x2-1) can be appropriately adjusted depending on the purpose and are not particularly limited.

[0358] The energy ray-curable resin composition (x2-1) preferably further contains a solvent because its handling properties are improved by dilution.

[0359] 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).

[0360] 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 solvents are used in combination, the combination and ratio thereof may be arbitrarily selected.

[0361] (Other ingredients)

[0362] In addition to the above-mentioned energy ray curing components, the energy ray curing resin composition (x2-1) may also contain appropriate amounts of components other than curing components, 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 previously.

[0363] (Method for producing energy ray-curable resin composition (x2-1))

[0364] The energy ray-curable resin composition (x2-1) can be obtained by mixing the components constituting the composition. The order of adding the components during mixing is not particularly limited, and two or more components may be added simultaneously.

[0365] When a solvent is used, the solvent may be mixed with any other ingredients other than the solvent to dilute the ingredients before use, or the solvent may be mixed with the ingredients without diluting them before use. The method for mixing the ingredients during mixing is not particularly limited and may be appropriately selected from among the following known methods: mixing by rotating a stirring bar or paddle, mixing using a mixer, mixing by applying ultrasonic waves, and the like.

[0366] The temperature and time during addition and mixing of the components are not particularly limited as long as the components do not deteriorate, and can be adjusted appropriately. However, the temperature is preferably 15 to 30°C.

[0367] Support Plate (Y)

[0368] The support sheet (Y) functions as a support for supporting the curable resin film (x).

[0369] like Figure 2 As shown, the support sheet (Y) can be composed only of the substrate 11, as shown in FIG. Figure 3 As shown, it can be a laminate of a substrate 11 and an adhesive layer 21, such as Figure 4 As shown, the laminate may be a laminate formed by sequentially laminating the substrate 11, the intermediate layer 31, and the adhesive layer 21. The laminate formed by sequentially laminating the substrate 11, the intermediate layer 31, and the adhesive layer 21 is suitable for use as a back grinding tape.

[0370] Hereinafter, the base material of the support sheet (Y), the adhesive layer and the intermediate layer which the support sheet (Y) optionally has will be described.

[0371] <Base material>

[0372] The substrate is in a sheet or film shape, and examples of its constituent materials include the following various resins.

[0373] Examples of the resin constituting the substrate include polyethylenes such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE); polyolefins other than polyethylenes such as polypropylene, polybutene, polybutadiene, polymethylpentene, and norbornene resins; ethylene copolymers (copolymers obtained using ethylene as a monomer) such as ethylene-vinyl acetate copolymers, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylate copolymers, and ethylene-norbornene copolymers; and vinyl chlorides such as polyvinyl chloride and vinyl chloride copolymers. Polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene isophthalate, polyethylene 2,6-naphthalate, and wholly aromatic polyesters in which all structural units have aromatic cyclic groups; copolymers of two or more of the above polyesters; poly(meth)acrylates; polyurethanes; polyurethane acrylates; polyimides; polyamides; polycarbonates; fluororesins; polyacetals; modified polyphenylene ethers; polyphenylene sulfides; polysulfones; and polyether ketones.

[0374] In addition, examples of the resin constituting the substrate include polymer alloys such as mixtures of the aforementioned polyester and other resins. In the polymer alloys of the aforementioned polyester and other resins, the amount of the resin other than the polyester is preferably relatively small.

[0375] Examples of the resin constituting the substrate include crosslinked resins obtained by crosslinking one or more of the resins listed above; and modified resins such as ionomers using one or more of the resins listed above.

[0376] The resin constituting the substrate may be used alone or in combination of two or more. When two or more resins are used to constitute the substrate, their combination and ratio may be arbitrarily selected.

[0377] The substrate may be a single layer (single layer) or may be a multilayer of two or more layers. When the substrate is a multilayer, the multilayers may be the same or different from each other, and the combination of the multilayers is not particularly limited.

[0378] The thickness of the substrate is preferably 5 μm to 1000 μm, more preferably 10 μm to 500 μm, further preferably 15 μm to 300 μm, and even more preferably 20 μm to 150 μm.

[0379] Here, the “thickness of the substrate” refers to the thickness of the entire substrate. For example, the thickness of a substrate including multiple layers refers to the total thickness of all layers constituting the substrate.

[0380] The substrate is preferably a substrate with high thickness accuracy, that is, preferably a substrate with suppressed thickness variation regardless of location. Among the above-mentioned constituent materials, examples of such materials with high thickness accuracy that can be used to constitute the substrate include polyethylene, polyolefins other than polyethylene, polyethylene terephthalate, and ethylene-vinyl acetate copolymer.

[0381] The base material may contain various known additives such as fillers, colorants, antistatic agents, antioxidants, organic lubricants, catalysts, and softeners (plasticizers) in addition to the above-mentioned main constituent materials such as the resin.

[0382] The substrate may be transparent or opaque, may be colored according to the purpose, or may have other layers deposited thereon. Furthermore, when the curable resin film (x) is an energy ray-curable resin film (x2), and when the adhesive layer is an energy ray-curable adhesive layer, the substrate is preferably an energy ray-transmitting substrate.

[0383] 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 above resin.

[0384] <Adhesive layer>

[0385] The adhesive layer is in a sheet or film form and contains an adhesive.

[0386] Examples of adhesives include adhesive resins such as acrylic resins (adhesives formed from resins having a (meth)acryloyl group), urethane resins (adhesives formed from resins having a urethane bond), rubber resins (adhesives formed from resins having a rubber structure), silicone resins (adhesives formed from resins having a siloxane bond), epoxy resins (adhesives formed from resins having an epoxy group), polyvinyl ether, and polycarbonate. Among these, acrylic resins are preferred.

[0387] It should be noted that, in the present invention, "adhesive resin" refers to a concept that includes both resins having adhesive properties and resins having adhesion properties. For example, it includes not only resins that have adhesive properties themselves, but also resins that show adhesive properties by being used in combination with other components such as additives, and resins that show adhesive properties due to the presence of triggering factors such as heat or water.

[0388] The adhesive layer may be a single layer (single layer) or may be a plurality of layers. When the adhesive layer is a plurality of layers, the plurality of layers may be the same or different from each other, and the combination of the plurality of layers is not particularly limited.

[0389] The thickness of the adhesive layer is preferably 1 μm to 1000 μm, more preferably 5 μm to 500 μm, and even more preferably 10 μm to 100 μm. Here, the "thickness of the adhesive layer" refers to the thickness of the entire adhesive layer. For example, the thickness of an adhesive layer comprising multiple layers refers to the total thickness of all layers constituting the adhesive layer.

[0390] The adhesive layer may be formed using an energy ray curable adhesive or a non-energy ray curable adhesive. The adhesive layer formed using an energy ray curable adhesive can easily adjust the physical properties before and after curing.

[0391] <Middle layer>

[0392] The intermediate layer is in the form of a sheet or film, and its constituent material can be appropriately selected depending on the intended purpose and is not particularly limited. For example, when the purpose is to suppress deformation of the protective film (X) by reflecting the shape of bumps present on the semiconductor surface on the protective film covering the semiconductor surface, preferred constituent materials for the intermediate layer include urethane (meth)acrylates, etc., from the perspectives of improving unevenness conformability, improving bump penetration, and further improving the adhesiveness of the intermediate layer.

[0393] The intermediate layer may be a single layer (single layer) or may be a plurality of layers. When the intermediate layer is a plurality of layers, the plurality of layers may be the same or different from each other, and the combination of the plurality of layers is not particularly limited.

[0394] The thickness of the intermediate layer can be appropriately adjusted according to the height of the bumps on the semiconductor surface to be protected. From the perspective of easily absorbing the effects of taller bumps, the thickness is preferably 50 μm to 600 μm, more preferably 70 μm to 500 μm, and even more preferably 80 μm to 400 μm. Here, the "thickness of the intermediate layer" refers to the thickness of the entire intermediate layer. For example, the thickness of an intermediate layer comprising multiple layers refers to the total thickness of all layers constituting the intermediate layer.

[0395] Next, a method for producing the protective film-forming sheet will be described.

[0396] [Method for producing a protective film-forming sheet]

[0397] The protective film-forming sheet can be produced by sequentially laminating the above-mentioned layers so as to have corresponding positional relationships.

[0398] For example, when manufacturing a support sheet, when laminating an adhesive layer or an intermediate layer on a substrate, the adhesive layer or the intermediate layer can be laminated by applying an adhesive composition or an intermediate layer-forming composition on the substrate and drying or irradiating the substrate with energy rays as needed.

[0399] Examples of the coating method include spin coating, spray coating, bar coating, knife coating, roll coating, knife roll coating, blade coating, die coating, and gravure coating.

[0400] On the other hand, for example, when a curable resin film (x) is further laminated on an adhesive layer already laminated on a substrate, a thermosetting resin composition (x1-1) or an energy line curable resin composition (x2-1) can be applied on the adhesive layer to directly form the curable resin film (x).

[0401] Likewise, when a pressure-sensitive adhesive layer is further laminated on an intermediate layer laminated on a substrate, the pressure-sensitive adhesive layer can be directly formed by applying a pressure-sensitive adhesive composition on the intermediate layer.

[0402] In this way, when forming a laminate structure with two continuous layers using any composition, a further composition can be applied to the layer formed with the aforementioned composition to form a new layer. Preferably, the layer to be laminated later is pre-formed using the aforementioned composition on a separate release film. The exposed surface of the completed layer, opposite to the side in contact with the release film, is then bonded to the exposed surface of the remaining layer, thereby forming a laminate structure with two continuous layers. In this case, the aforementioned composition is preferably applied to the release-treated surface of the release film. After the laminate structure is formed, the release film can be removed as needed.

[0403] [Method for Manufacturing a Semiconductor Wafer with a Protective Film Using a Protective Film-Forming Sheet]

[0404] The method for producing a semiconductor wafer with a protective film of the present invention can be implemented using the above-mentioned protective film-forming sheet of the present invention.

[0405] Specifically, it includes the following steps (S1) to (S3).

[0406] Step (S1): a step of preparing a semiconductor wafer having a bump forming surface provided with a plurality of bumps

[0407] Step (S2): a step of laminating the protective film-forming sheet of the present invention to the bump-forming surface of the semiconductor wafer while pressing the sheet with the curable resin film (x) as the adhesive surface.

[0408] Step (S3): a step of curing the curable resin film (x) to form a protective film (X)

[0409] Hereinafter, a semiconductor wafer to which the present invention is applied will be described in detail, and a method for manufacturing a semiconductor wafer with a protective film according to the present invention will be described.

[0410] <Step (S1)>

[0411] In step ( S1 ), a semiconductor wafer having a bump formation surface on which a plurality of bumps are provided is prepared.

[0412] An example of a semiconductor wafer having a bump forming surface provided with a plurality of bumps used in the method for producing a semiconductor wafer with a protective film of the present invention is shown in FIG. Figure 5 The semiconductor wafer 40 with bumps includes a plurality of bumps BM on a bump formation surface (circuit surface) 41 a of a semiconductor wafer 41 .

[0413] In the following description, a "semiconductor wafer having bumps" is also referred to as a "wafer with bumps." A "semiconductor wafer" is also simply referred to as a "wafer."

[0414] Circuits such as wiring, capacitors, diodes, and transistors are formed on the surface of the wafer 41. The material of the wafer is not particularly limited, and examples thereof include silicon wafers, silicon carbide wafers, compound semiconductor wafers, sapphire wafers, and glass wafers.

[0415] The size of the wafer 41 is not particularly limited. From the perspective of improving batch processing efficiency, it is generally 8 inches (200 mm in diameter) or larger, and preferably 12 inches (300 mm in diameter) or larger. It should be noted that the shape of the wafer is not limited to a circle, and can be a quadrilateral such as a square or rectangle. In the case of a quadrilateral wafer, from the perspective of improving batch processing efficiency, the length of the longest side of the wafer 41 is preferably greater than the above-mentioned size (diameter).

[0416] The thickness of the wafer 41 is not particularly limited, but is preferably 100 μm to 1000 μm, more preferably 200 μm to 900 μm, and even more preferably 300 μm to 800 μm from the viewpoint of easily suppressing warping of the wafer 41 associated with curing the curable resin film (x).

[0417] The shape of the bump BM is not particularly limited, and can be any shape as long as it can contact and fix the electrode on the substrate for chip mounting. Figure 5 In the embodiment, the bump BM is formed into a spherical shape, but the bump BM may also be a rotational ellipsoid. The rotational ellipsoid may be, for example, a rotational ellipsoid extending in the vertical direction relative to the bump forming surface 41a of the wafer 41 or a rotational ellipsoid extending in the horizontal direction relative to the bump forming surface 41a of the wafer 41.

[0418] In addition, if Figure 6 As shown, the bump BM may be pillar-shaped.

[0419] In addition, as a material of the bump BM, solder can be mentioned, for example.

[0420] Here, in the present invention, a semiconductor wafer having bumps with a narrowed pitch, which is defined by the requirements described below, is an application target.

[0421] Specifically, the present invention forms a protective film (X) on the bump-forming surface of a semiconductor wafer having narrowed-pitch bumps using a protective film-forming sheet, thereby suppressing the flattening and deformation of the narrowed-pitch bumps and preventing short circuits between the bumps. In other words, the semiconductor wafer to which the present invention is applied is a semiconductor wafer having narrowed-pitch bumps, which, without the protective film (X) formed, presents a risk of short circuits due to flattening and deformation of the bumps.

[0422] The semiconductor wafer described below is a semiconductor wafer having bumps with a narrowed pitch, which has a risk of causing a short circuit due to collapse or deformation of the bumps when a protective film (X) is not formed.

[0423] Semiconductor Chip

[0424] The protective film forming sheet of the present invention is used for forming a protective film (X) on the bump formation surface of a semiconductor wafer that satisfies the following requirements (α1) to (α2).

[0425] Furthermore, 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).

[0426] Requirement (α1): The width of the bump (BM w )(unit: μm) is 20μm to 350μm.

[0427] 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).

[0428] [(BM P ) / (BM w )]≤1.0····(I)

[0429] The above requirements (α1) to (α2) are indicators indicating that a semiconductor wafer having bumps with narrowed pitches is susceptible to short circuits caused by crushing and deformation of the bumps.

[0430] To express the bump pitch (BM P )(unit: μm) and the width of the bump (BM w ) (unit: μm), the three bumps BM_a, BM_b, and BM_c formed on the bump forming surface of the wafer 41 are shown in an enlarged top view. Figure 7 .

[0431] Bump pitch (BM P ) is the shortest distance between two bumps. Figure 7 In FIG, the shortest distance between bump BM_a and bump BM_b is P1. In addition, the shortest distance between bump BM_b and bump BM_c is P2.

[0432] Bump width (BM w) is the length of the straight line b1-b2 connecting b1 and point b2, b1 is the intersection of the straight line P1 connecting bump BM_a and bump BM_b and bump BM_b, and b2 is the intersection of the straight line P2 connecting bump BM_b and bump BM_c and bump BM_b.

[0433] It should be noted that the bump pitch (BM P )(unit: μm) and the width of the bump (BM w ) (unit: μm) can be measured based on the above definition by, for example, optical microscope observation.

[0434] It should be noted that when at least one of the bumps among the plurality of bumps on the wafer satisfies the above requirements (α1) to (α2), there is a risk of short circuits occurring between the bumps due to the narrow pitch between the bumps.

[0435] Therefore, a wafer to which the present invention is applied is a wafer in which the above-mentioned requirements (α1) to (α2) are satisfied between at least any one of the plurality of bumps present on the wafer.

[0436] Here, the width of the bump (BM) defined by the requirement (α1) w ) (unit: μm) is 20 μm to 350 μm. That is, according to the present invention, it is possible to w ) is targeted at wafers with multiple bumps of 20 μm or more and less than 150 μm (particularly 20 μm to 100 μm). In other words, wafers with narrow pitch and multiple tiny bumps can be targeted. In addition, wafers with a bump width (BM) of w ) wafers with multiple bumps ranging in size from 150μm to 350μm. In other words, wafers with narrow pitch and multiple wide bumps can also be targeted. Wafers with narrow pitch and multiple wide bumps are particularly susceptible to short circuits between bumps, but the present invention can suppress short circuits between bumps in such wafers.

[0437] Here, the value of [(BMP) / (BMw)] defined by the requirement (α2) is one of the indicators indicating the susceptibility of short circuits between bumps, and this value may be 0.9 or less, or 0.8 or less.

[0438] Here, the chip may also satisfy the following requirement (α3a) or the following requirement (α3b).

[0439] Requirement (α3a): The height of the bump (BM h ) and the width of the bump (BM w ) satisfies the following formula (IIIa)

[0440] 0.2≤[(BMh ) / (BM w )]≤1.0····(IIIa)

[0441] Requirement (α3b): The height of the bump (BM h ) and the width of the bump (BM w ) satisfies the following formula (IIIb)

[0442] 0.5≤[(BM h ) / (BM w )]≤5.0····(IIIb)

[0443] The above requirement (α3a) is an indicator indicating that the bump is a ball bump, [(BM h ) / (BM w The closer the value of )] is to 1.0, the closer it is to a true sphere, and the closer it is to 0.2, the closer it is to a rotational ellipsoid that is extended in the horizontal direction relative to the bump forming surface 41a of the wafer 41.

[0444] When semiconductor wafers with such ball bumps are singulated into semiconductor chips and electrically connected to a wiring substrate via the ball bumps, the ball bumps are flattened and expanded laterally, causing short circuits due to contact between the ball bumps. Furthermore, to meet the demand for even higher-density packaging, three-dimensional high-density packaging, in which semiconductor packages are stacked vertically, has been explored. In this case, the ball bumps are gradually flattened by the weight of the semiconductor packages, sometimes leading to short circuits. The present invention can suppress short circuits caused by contact between ball bumps.

[0445] The above requirement (α3b) is an indicator indicating that the bump is a stud bump, [(BM h ) / (BM w The closer the value of )] is to 5.0, the higher the aspect ratio of the stud bump is, and the closer it is to 0.5, the lower the aspect ratio of the stud bump is.

[0446] For semiconductor wafers with such column bumps, during the process of singulating them into semiconductor chips and electrically connecting the semiconductor chips to the wiring substrate via the column bumps, the column bumps deform and bend, and the column bumps may come into contact with each other, causing a short circuit. In addition, there is also the problem of poor connection caused by the deformation and bending of the column bumps. In addition, in order to meet the requirements of further high-density installation, three-dimensional high-density installation in which semiconductor packages are stacked in the height direction has also been explored. In this case, the column bumps are gradually flattened by the weight of the semiconductor package, which sometimes causes a short circuit. According to the present invention, short circuits caused by contact between column bumps can be suppressed. In addition, poor connection caused by deformation of the column bumps can also be suppressed.

[0447] It should be noted that the height of the bump (BM h ) refers to the distance between the straight line connecting the contact point of the bump with the bump forming surface and the part of the bump located farthest from the bump forming surface when focusing on one bump.

[0448] Bump height (BM h ) can specifically be a value limited by the following requirement (α4).

[0449] Requirement (α4): The height of the bump (BM h ) is 15μm~300μm

[0450] That is, in one embodiment of the present invention, it is also possible to have a bump height (BM h ) as the target. In addition, it is also possible to target wafers with multiple bumps of 20μm or more and less than 150μm (especially 20μm to 100μm). h ) The target is a wafer with multiple bumps of 150μm to 350μm in height.

[0451] Bump height (BM h ) can be measured by, for example, cutting a semiconductor wafer with bumps in a direction perpendicular to the bump forming surface and through the center of the bumps, and observing the cut cross section under an optical microscope.

[0452] <Step (S2)>

[0453] The outline of step (S2) is shown in Figure 8 .

[0454] In step ( S2 ), the protective film forming sheet 1 of the present invention is bonded to the bump forming surface 41 a of the semiconductor wafer 41 while being pressed with the curable resin film (x) serving as the bonding surface.

[0455] Thus, the bump formation surface 41a of the semiconductor wafer 41 can be covered with the curable resin film (x), and the curable resin film (x) can also be filled between the plurality of bumps BM.

[0456] It should be noted that, from the perspective of filling the curable resin film (x) well between the multiple bumps BM, the pressing pressure when the protective film forming sheet 1 is adhered to the bump forming surface 41a of the semiconductor chip 41 is preferably 1kPa to 200kPa, more preferably 5kPa to 150kPa, and further preferably 10kPa to 100kPa.

[0457] It should be noted that the pressing force when laminating the protective film forming sheet 1 to the bump forming surface 41a of the semiconductor wafer 41 can be appropriately varied from the initial stage to the final stage of lamination. For example, from the perspective of better filling the curable resin film (x) between the plurality of bumps BM, it is preferable to reduce the pressing force at the initial stage of lamination and gradually increase the pressing force.

[0458] In addition, when the protective film forming sheet 1 is attached to the bump forming surface 41a of the semiconductor wafer 41, if the curable resin film (x) is a thermosetting resin film (x1), it is preferably heated from the perspective of better filling the curable resin film (x) between the multiple bumps BM. In the case where the curable resin film (x) is a thermosetting resin film (x1), the fluidity of the thermosetting resin film (x1) is temporarily improved by heating, and it is cured by continuing to heat. Therefore, by heating within a range that improves the fluidity of the thermosetting resin film (x1), the thermosetting resin film (x1) easily fills the space between the multiple bumps BM, and the filling property of the thermosetting resin film (x1) between the multiple bumps BM is further improved.

[0459] As a specific heating temperature (lamination temperature), 50-150 degreeC is preferable, 60-130 degreeC is more preferable, and 70-110 degreeC is further more preferable.

[0460] It should be noted that the heat treatment performed on the thermosetting resin film (x1) is not included in the curing treatment of the thermosetting resin film (x1).

[0461] Furthermore, when attaching the protective film-forming sheet 1 to the bump-forming surface 41a of the semiconductor wafer 41, the process can be performed under a reduced pressure environment. This creates a negative pressure between the plurality of bumps BM, making it easier for the curable resin film (x) to fill the space between the plurality of bumps BM. As a result, the filling capacity of the curable resin film (x) between the plurality of bumps BM is further 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.

[0462] <Step (S3)>

[0463] After the step (S2) is performed, the step (S3) is performed. Specifically, Figure 9 As shown, the curable resin film (x) is cured to obtain a semiconductor wafer with a protective film.

[0464] 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.), so the bump neck can be well protected by forming the protective film (X).

[0465] In addition, in the present invention, since a sheet for forming a protective film that meets the above-mentioned requirements (β1) to (β3) is used, as described above, for a semiconductor chip with bumps having narrowed pitches, which has the potential risk of short circuits due to flattening or deformation of the bumps, the flattening and deformation of the bumps can be suppressed, and short circuits caused by contact between the bumps can be avoided.

[0466] The curing of the curable resin film (x) can be performed by either thermal curing or curing by energy ray irradiation, depending on the type of the curable component contained in the curable resin film (x).

[0467] As conditions for thermal curing, the curing temperature is preferably 90° C. to 200° C., and the curing time is preferably 1 hour to 3 hours.

[0468] The conditions for curing by energy ray irradiation can be appropriately set according to the type of energy ray to be used. For example, when ultraviolet rays are used, the illuminance is preferably 170 mW / cm 2 ~250mw / cm 2 , the light intensity is preferably 300mJ / cm 2 ~3000mJ / cm 2 .

[0469] Here, in the process of curing the curable resin film (x) to form the protective film (X), from the perspective of removing bubbles and the like that are trapped when the curable resin film (x) is used to fill 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) is temporarily increased by heating, and the film is cured by continuing to heat the film. When the fluidity of the thermosetting resin film (x1) is increased by utilizing this phenomenon, bubbles and the like that are trapped when the thermosetting resin film (x1) is used to fill the spaces between the plurality of bumps BM can be removed, and the thermosetting resin film (x1) can be cured on the basis of achieving a better filling property of the thermosetting resin film (x1) between the plurality of bumps BM.

[0470] Moreover, from the viewpoint of shortening the curing time, the curable resin film (x) is preferably an energy ray-curable resin film (x1).

[0471] It should be noted that by peeling off the support sheet (Y) before curing the curable resin film (x), curing the curable resin film (x) to form the protective film (X), a semiconductor wafer with a protective film can be obtained. However, the present invention is not limited to this embodiment, and a semiconductor wafer with a protective film can be obtained by peeling off the support sheet (Y) after curing the curable resin film (x) to form the protective film (X).

[0472] 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) to thin the semiconductor wafer 41. The back grinding may be performed before or after curing the curable resin film (x).

[0473] Moreover, when performing a back grinding process, from the viewpoint of performing the back grinding process satisfactorily, the support sheet (Y) is preferably a back grinding tape.

[0474] Alternatively, after curing the curable resin film (x), the protective film (X) covering the bump top or the protective film (X) adhering to a portion of the bump top may be removed to expose the bump top.

[0475] Examples of the exposure process for exposing the bump tops include etching processes such as wet etching and dry etching.

[0476] Here, as the dry etching process, for example, plasma etching process or the like can be cited.

[0477] In addition, when the top of the bump is not exposed on the surface of the protective film, an exposure process may be performed for the purpose of retreating the protective film until the top of the bump is exposed.

[0478] [Method for manufacturing a semiconductor chip with a protective film]

[0479] The method for producing a semiconductor chip with a protective film of the present invention includes the following steps (T1) to (T2).

[0480] Step (T1): A step of carrying out the method for producing a semiconductor wafer with a protective film of the present invention to obtain a semiconductor wafer with a protective film.

[0481] Step (T2): a step of singulating the semiconductor wafer with the protective film

[0482] <Process (T1)>

[0483] In step (T1), the 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.

[0484] <Process (T2)>

[0485] In step (T2), the semiconductor wafer with a protective film obtained in step (T1) is divided into individual pieces.

[0486] The singulation method is not particularly limited, and a known singulation method can be appropriately adopted. Specific examples include laser dicing, blade dicing, and stealth dicing (registered trademark).

[0487] Note that, before performing 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 a protective film may be included.

[0488] [Method for manufacturing a semiconductor package]

[0489] The method for manufacturing a semiconductor package of the present invention includes the following steps (U1) to (U2).

[0490] Step (U1): A step of carrying out the method for producing a semiconductor chip with a protective film of the present invention to obtain a semiconductor chip with a protective film.

[0491] Step (U2): A step of electrically connecting the wiring substrate and the semiconductor chip with the protective film via the bumps.

[0492] <Process (U1)>

[0493] In step (U1), the method for manufacturing a semiconductor chip with a protective film of the present invention is carried out to obtain a semiconductor chip with a protective film.

[0494] <Process (U2)>

[0495] like Figure 10 As shown, in step (U2), the wiring substrate (Z) having the wiring Z1 and the semiconductor chip CP with a protective film are electrically connected via the bumps BM.

[0496] More specifically, the bump-forming surface of the semiconductor chip CP with the protective film and the wiring Z1-forming surface of the wiring substrate (Z) are heated so as to face each other with the bump BM interposed therebetween (hereinafter also referred to as the "heating and connecting step"). This allows for good electrical connection between the top of the bump BM and the wiring Z1.

[0497] Moreover, in the present invention, although a semiconductor chip obtained from a semiconductor wafer having bumps with narrowed pitch, which has the potential risk of short circuit due to flattening or deformation of the bumps, is used, by making the protective film forming sheet of the present invention satisfy the above-mentioned requirements (β1) to (β3), among which, in particular, by satisfying the above-mentioned requirement (β2), the contact between the bumps caused by the flattening or deformation of the bumps can be suppressed during the heating connection process, and the short circuit caused by the contact between the bumps can be avoided.

[0498] The conditions of the heat connection step are, for example, a temperature of 250° C. to 270° C. and a time of 30 seconds to 5 minutes.

[0499] <Process (U3)>

[0500] The method for manufacturing a semiconductor package according to one embodiment of the present invention further includes the following step (U3).

[0501] Step (U3): Filling the gap between the wiring substrate and the semiconductor chip with the protective film with an underfill material

[0502] In the present invention, as described above, it is possible to prevent bumps from coming into contact with each other due to the flattening or deformation of the bumps. In other words, it is possible to prevent bumps from coming close to each other due to the flattening or deformation of the bumps. In the past, if the bumps were close to each other, even if you wanted to fill the gap with underfill material, it was difficult to fill the gap with underfill material because the gap between the bumps was narrow. However, in the present invention, since the approach of the bumps is suppressed, it is possible to well fill the gap between the protective film (X) and the wiring substrate (Z), including the gap between the bumps, with underfill material.

[0503] Example

[0504] The present invention will be described in detail with reference to the following examples, but the present invention is not limited to the following examples.

[0505] [Measurement methods of various physical properties]

[0506] The physical property values ​​in the following Examples and Comparative Examples are values ​​measured by the following methods.

[0507] <Weight average molecular weight>

[0508] The measurement was performed using a gel permeation chromatography apparatus (manufactured by Tosoh Corporation, product name "HLC-8020") under the following conditions, and the measured value in terms of standard polystyrene was used.

[0509] (Measurement conditions)

[0510] Column: A column made by connecting "TSK guard column HXL-L," "TSK gel G2500HXL," "TSK gel G2000HXL," and "TSK gel G1000HXL" (all manufactured by Tosoh Corporation) in this order

[0511] Column temperature: 40°C

[0512] Elution solvent: tetrahydrofuran

[0513] Flow rate: 1.0 mL / min

[0514] <Measurement of thickness of each layer>

[0515] Thicknesses other than the thickness (XT) of the protective film (after curing) were measured using a constant pressure thickness gauge manufactured by Teclock (model: "PG-02J", standard specifications: in accordance with JIS K6783, Z1702, and Z1709).

[0516] Glass transition temperature

[0517] 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 ramp rate of 10°C / min using a differential scanning calorimeter (PYRIS Diamond DSC) manufactured by PerkinElmer, and identifying an inflection point.

[0518] <Epoxy equivalent>

[0519] Measured in accordance with JIS K 7236:2009.

[0520] <Average particle size>

[0521] The particles to be measured were dispersed in water using ultrasound, and the particle size distribution of the particles was measured on a volume basis using a dynamic light scattering particle size distribution analyzer (LB-550, manufactured by Horiba, Ltd.). The median particle size (D 50 ) as the average particle size.

[0522] [Examples 1-4, Comparative Examples 1-2]

[0523] The thermosetting resin composition (x1-1) used for producing the thermosetting resin film (x1) used in the examples was prepared by the following method.

[0524] <Raw materials of thermosetting resin composition (x1-1)>

[0525] (Polymer component (A))

[0526] Polyvinyl butyral (S-LEC (registered trademark) B BL-10 manufactured by Sekisui Chemical Co., Ltd., with a weight-average molecular weight of 25,000 and a glass transition temperature of 59°C, having structural units represented by the following formula (i-1), the following formula (i-2), and the following formula (i-3) was used. In the following formula, p is 68 to 74 mol%, q is 1 to 3 mol%, and r is approximately 28 mol%).

[0527] [Chemical Formula 2]

[0528]

[0529] (Epoxy resin (B1))

[0530] The following two types of epoxy resins were used.

[0531] Epoxy resin (B1-1): liquid bisphenol A-type epoxy resin (manufactured by DIC Corporation, EPICLON (registered trademark) EXA-4850-1000, epoxy equivalent 404 to 412 g / eq)

[0532] Epoxy resin (B1-2): dicyclopentadiene-type epoxy resin (manufactured by DIC Corporation, EPICLON (registered trademark) HP-7200, epoxy equivalent 254 to 264 g / eq)

[0533] (Thermosetting agent (B2))

[0534] A novolac-type phenolic resin (Shonol (registered trademark) BRG-556 manufactured by Showa Denko K.K.) was used.

[0535] (Curing accelerator (C))

[0536] 2-Phenyl-4,5-dihydroxymethylimidazole (CUREZOL (registered trademark) 2PHZ manufactured by Shikoku Chemicals Co., Ltd.) was used.

[0537] (Filling material (D))

[0538] Spherical silica modified with an epoxy group (manufactured by Admatechs, admanano (registered trademark) YA050C-MKK, average particle size 0.05 μm) was used.

[0539] <Preparation of thermosetting resin composition (x1-1)>

[0540] The polymer component (A), epoxy resin (B1-1), epoxy resin (B1-2), thermosetting agent (B2), curing accelerator (C) and filler (D) were dissolved or dispersed in methyl ethyl ketone so as to achieve the following contents based on the total amount (100% by 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% by mass.

[0541] 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.

[0542] (Cooperation 1)

[0543] Polymer component (A): 41.4% by mass

[0544] Epoxy resin (B1-1): 23.2% by mass

[0545] Epoxy resin (B1-2): 15.2% by mass

[0546] Thermal curing agent (B2): 11.2% by mass

[0547] Curing accelerator (C): 0.2 mass%

[0548] Filler (D): 8.8 mass%

[0549] (Cooperation 2)

[0550] Polymer component (A): 19.9% ​​by mass

[0551] Epoxy resin (B1-1): 33.1% by mass

[0552] Epoxy resin (B1-2): 21.7% by mass

[0553] Thermal curing agent (B2): 16.1% by mass

[0554] Curing accelerator (C): 0.2 mass%

[0555] Filler (D): 9.0 mass%

[0556] <Production of thermosetting resin film (x1)>

[0557] A thermosetting resin composition (x1-1) prepared according to Formulation 1 was applied to the release-treated surface of a polyethylene terephthalate release material (SP-PET381031, manufactured by Lintec Co., Ltd., 38 μm thick) having a release-treated surface treated with silicone. The film was then heat-dried at 120°C for 2 minutes to obtain a 30 μm thick thermosetting resin film (x1: Formulation 1). A 50 μm thick thermosetting resin film (x1: Formulation 2) was obtained by the same method, except that the thermosetting resin composition (x1-1) prepared according to Formulation 2 was used.

[0558] <Manufacturing of a protective film-forming sheet>

[0559] As a support sheet (Y), an adhesive tape (manufactured by Lintec Co., Ltd., E-8510HR) was used in which a base material (thickness: 100 μm), an intermediate layer (thickness: 400 μm) and an adhesive layer (thickness: 10 μm) were stacked in this order. The adhesive layer of the adhesive tape was bonded to a thermosetting resin film (x1: combination 1) with a thickness of 30 μm formed on a release material to produce a sheet 1 for forming a protective film in which a support sheet (Y), a thermosetting resin film (x1) and a release material were stacked in this order.

[0560] A protective film-forming sheet 2 was produced by the same procedure for a thermosetting resin film (x1: blend 2) having a thickness of 50 μm.

[0561] [Measurement of tensile modulus E' of protective film (X)]

[0562] After curing the thermosetting resin film (x1), the tensile modulus E' of the protective film (X) was measured by the following method.

[0563] First, six sheets of 30 μm thick thermosetting resin films (x1: combination 1) were overlapped to produce 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 heat-treated in a pressurized oven (RAD-9100 manufactured by Lintec Co., Ltd.) at a temperature of 130°C, a time of 2 h, and a furnace pressure of 0.5 MPa to obtain a protective film (X).

[0564] Next, the tensile modulus E' (23°C) of the protective film (X) was measured using a dynamic viscoelasticity measuring apparatus (manufactured by TA Instruments, product name "DMA Q800") in a tensile mode at a frequency of 11 Hz, at 23°C, and in an air atmosphere. Separately, the tensile modulus E' (260°C) of the protective film (X) was measured under the same conditions, except that the temperature during measurement was set at 260°C.

[0565] For the thermosetting resin film (x1: combination 2), four sheets of thermosetting resin films (x1: combination 2) with a thickness of 50 μm were overlapped and the thickness was set to 0.20 mm. In addition, a protective film (X) was obtained by the same steps, 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.

[0566] [Short Circuit Evaluation]

[0567] The release material was removed from the protective film-forming sheet obtained above, and the surface of the thermosetting resin layer thus exposed (exposed surface) was press-bonded to the bump-forming surface of the wafer with ball bumps, thereby attaching the protective film-forming sheet to the bump-forming surface of the semiconductor wafer. The protective film-forming sheet was attached using a laminating device (a roll laminator, "RAD-3510F / 12" manufactured by Lintec Co., Ltd.) at a table temperature of 90°C, a laminating speed of 2 mm / sec, and a laminating pressure of 0.5 MPa while heating the thermosetting resin film (x1). The details of the wafer with ball bumps attached to which the protective film-forming sheet 1 or 2 was attached (elements (α1), (α2), (α3a), and (α4)) are shown in Table 1.

[0568] Next, ultraviolet irradiation was performed using RAD-2700 manufactured by Lintec Corporation, and the support sheet (Y) of the protective film forming sheet was peeled off.

[0569] The chip with bumps attached to a thermosetting resin film (x1) was heat-treated in a pressurized oven (RAD-9100 manufactured by Lintec Corporation) at a temperature of 130°C, a time of 2 hours, and a furnace pressure of 0.5 MPa to thermally cure the thermosetting resin film (x1) and obtain a semiconductor chip with a protective film (X) (Examples 1 to 4).

[0570] The semiconductor wafer with the protective film (X) was cut in a direction perpendicular to the bump formation surface and passing through the center of the bump, and the cut cross section was observed under an optical microscope to measure the thickness (X) of the protective film (X). T ).

[0571] Then, the bump-forming surface of the semiconductor wafer with the protective film (X) and the wiring-forming surface of the wiring substrate were placed opposite each other with the bumps interposed therebetween, and a heat treatment (heat connection step) was performed at 260°C for 1 minute to evaluate whether there was contact between the bumps (whether there was a short circuit).

[0572] As a comparative test, wafers with bumps similar to those in Examples 1 and 3 and Examples 2 and 4 but without a protective film (X) formed thereon were subjected to a heat connection step to evaluate the presence or absence of short circuits (Comparative Examples 1 and 2).

[0573] The results are shown in Table 1.

[0574] [Table 1]

[0575]

[0576] The following conclusions can be drawn from Table 1.

[0577] In Examples 1 to 4, although a semiconductor wafer having bumps with narrowed pitches was used, short circuiting of the bumps was achieved.

[0578] On the other hand, it was found that when the protective film (X) was not provided as in Comparative Examples 1 and 2, it was not possible to suppress bump short circuits in a semiconductor wafer having bumps with narrowed pitches.

Claims

1. A protective film-forming sheet 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) and a thermosetting component (B), wherein the polymer component (A) includes polyvinyl acetal and the thermosetting component (B) includes an epoxy resin (B1). The protective film forming sheet is used for forming a protective film (X) on the bump formation 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 ) is 20μm~350μm, Requirement (α2): The pitch of the bumps (BM P ) and the width of the bump (BM w ) satisfies the following formula (I), [(BM P ) / (BM w )]≤1.0····(I) in, The protective film forming sheet 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~1×10 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~1×10 8 Pa, Requirement (β3): The thickness (X) of the protective film (X) formed by curing the curable resin film (x) at 23°C is T ) and the height of the bump (BM h ) satisfies the following formula (II), The width of the bump (BM w ), the pitch of the bumps (BM P ), the width of the bump (BM w ), the thickness (X) of the protective film (X) at 23°C T ) and the height of the bump (BM h ) are all in μm, [(X T ) / (BM h )]≥0.2····(II).

2. The protective film-forming sheet according to claim 1, 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····(IIIa)。 3. The protective film-forming sheet according to claim 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 protective film-forming sheet according to any one of claims 1 to 3, further satisfying the following requirement (α4): Requirement (α4): The height of the bump (BM h ) is 15μm~300μm. 5 . The protective film-forming sheet according to claim 1 , wherein The support sheet (Y) is a back grinding tape.

6. The protective film-forming sheet according to claim 4, wherein The support sheet (Y) is a back grinding tape.

7. A method for manufacturing a semiconductor wafer with a protective film, the method comprising the following steps (S1) to (S3): Step (S1): a step of preparing a semiconductor wafer having a bump formation surface provided with a plurality of bumps; Step (S2): a step of laminating the protective film-forming sheet according to any one of claims 1 to 6 to the bump-forming surface of the semiconductor wafer while pressing the sheet with the curable resin film (x) as the adhesive surface; Step (S3): a step of curing the curable resin film (x) to form a protective film (X). in, The semiconductor wafer prepared in the step (S1) satisfies the following requirements (α1) to (α2), Requirement (α1): The width of the bump (BM w ) is 20μm~350μm, Requirement (α2): The pitch of the bumps (BM P ) and the width of the bump (BM w ) satisfies the following formula (I), The width of the bump (BM w ), the pitch of the bumps (BM P ) and the width of the bump (BM w ) are all in μm. [(BM P ) / (BM w )]≤1.0····(I).

8. A method for manufacturing a semiconductor chip with a protective film, the method 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. Step (T2): a step of dividing the semiconductor wafer with the protective film into individual pieces.

9. A method for manufacturing a semiconductor package, comprising the following steps (U1) to (U2): Step (U1): a step of carrying out the manufacturing method according to claim 8 to obtain a semiconductor chip with a protective film. Step (U2): A step of electrically connecting a wiring substrate and the semiconductor chip with a protective film via the bumps.

10. The method for manufacturing a semiconductor package according to claim 9, further comprising a step (U3): Step (U3): A step of filling an underfill material between the wiring substrate and the semiconductor chip with a protective film.

11. A protective film-forming sheet having a laminated structure of a curable resin film (x) and a support sheet (Y). The protective film forming sheet is used for forming a protective film (X) on the bump formation 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 ) is 20μm~350μm, Requirement (α2): The pitch of the bumps (BM P ) and the width of the bump (BM w ) satisfies the following formula (I), [(BM P ) / (BM w )]≤0.70····(I) in, The protective film forming sheet 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~1×10 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~1×10 8 Pa, Requirement (β3): The thickness (X) of the protective film (X) formed by curing the curable resin film (x) at 23°C is T ) and the height of the bump (BM h ) satisfies the following formula (II), The width of the bump (BM w ), the pitch of the bumps (BM P ), the width of the bump (BM w ), the thickness (X) of the protective film (X) at 23°C T ) and the height of the bump (BM h ) are all in μm, [(X T ) / (BM h )]≥0.2····(II).

12. The protective film forming sheet according to claim 11, 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····(IIIa)。 13. The protective film forming sheet according to claim 11, 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).

14. The protective film-forming sheet according to any one of claims 11 to 13, further satisfying the following requirement (α4): Requirement (α4): The height of the bump (BM h ) is 15μm~300μm. 15 . The protective film-forming sheet according to claim 11 , wherein The support sheet (Y) is a back grinding tape.

16. The protective film-forming sheet according to claim 14, wherein The support sheet (Y) is a back grinding tape.

17. A method for manufacturing a semiconductor wafer with a protective film, the method comprising the following steps (S1) to (S3): Step (S1): a step of preparing a semiconductor wafer having a bump formation surface provided with a plurality of bumps; Step (S2): a step of laminating the protective film-forming sheet according to any one of claims 11 to 16 to the bump-forming surface of the semiconductor wafer while pressing the sheet with the curable resin film (x) as the adhesive surface; Step (S3): a step of curing the curable resin film (x) to form a protective film (X). in, The semiconductor wafer prepared in the step (S1) satisfies the following requirements (α1) to (α2), Requirement (α1): The width of the bump (BM w ) is 20μm~350μm, Requirement (α2): The pitch of the bumps (BM P ) and the width of the bump (BM w ) satisfies the following formula (I), The width of the bump (BM w ), the pitch of the bumps (BM P ) and the width of the bump (BM w ) are all in μm. [(BM P ) / (BM w )]≤0.70····(I).

18. A method for manufacturing a semiconductor chip with a protective film, the method comprising the following steps (T1) to (T2): Step (T1): a step of carrying out the manufacturing method according to claim 17 to obtain a semiconductor wafer with a protective film, Step (T2): a step of dividing the semiconductor wafer with the protective film into individual pieces.

19. A method for manufacturing a semiconductor package, comprising the following steps (U1) to (U2): Step (U1): a step of carrying out the manufacturing method according to claim 18 to obtain a semiconductor chip with a protective film. Step (U2): A step of electrically connecting a wiring substrate and the semiconductor chip with a protective film via the bumps.

20. The method for manufacturing a semiconductor package according to claim 19, further comprising a step (U3): Step (U3): A step of filling an underfill material between the wiring substrate and the semiconductor chip with a protective film.

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