Dicing die bonding integrated film and manufacturing method thereof

Abstract

Disclosed is a dicing die bond film (10) provided with: a dicing film (5) comprising a base film (3) and a pressure-sensitive adhesive layer (2) provided on the base film (3); and an adhesive layer disposed on the pressure-sensitive adhesive layer (2) of the dicing film (5) and formed from the die bonding film (1). The loss tangent of the dicing film (5) at 0 DEG C is 0.15 or less.

Description

Technical Field

[0001] The invention relates to a dicing-die bonding integrated film and a manufacturing method thereof. Background Art

[0002] The semiconductor device is manufactured through the following steps: First, a dicing step is performed with the dicing pressure-sensitive adhesive film attached to the wafer, and then an expansion step, a pickup step, a die bonding step, etc. are performed.

[0003] In the manufacturing process of semiconductor devices, a dicing-die-bonding integrated film is sometimes used, which is formed by integrating a dicing film having a base film and a pressure-sensitive adhesive layer with a die-bonding film for bonding a substrate or other semiconductor chips. The dicing-die-bonding integrated film is used, for example, as follows. First, the surface of the die-bonding film (adhesive layer) side is attached to a wafer, and the wafer is cut while the wafer is fixed with a dicing ring. Thus, the wafer is singulated into a plurality of chips. Next, after the pressure-sensitive adhesive layer is irradiated with ultraviolet light to reduce the adhesive force of the pressure-sensitive adhesive layer on the die-bonding film, the die-bonding film sheet into which the chip and the die-bonding film are singulated is picked up from the pressure-sensitive adhesive layer together. Thereafter, the chip is mounted on a substrate, etc., via the die-bonding film sheet, and a semiconductor device is manufactured through this process. In addition, a stack formed by the chip obtained through the dicing process and the die-bonding film sheet attached thereto is referred to as a chip with a die-bonding film sheet.

[0004] In the past, as a method for cutting wafers and adhesive layers, cutting based on a blade or the like, i.e., blade cutting, is widely known. In recent years, with the high integration of semiconductor packages and the thinning of wafers, stealth dicing is becoming increasingly popular (see patent documents 1 and 2). Stealth dicing is a method in which a predetermined cutting line is formed inside the object to be processed by laser, and then the wafer and the die bonding film are cut along the predetermined cutting line, thereby obtaining a chip with a die bonding film attached.

[0005] Previous technical literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2002-192370

[0008] Patent Document 2: Japanese Patent Application Publication No. 2003-338467 Summary of the invention

[0009] Technical issues to be solved by the invention

[0010] In the manufacturing process of semiconductor devices, when the modified region is formed by stealth cutting for separation, expansion under cooling conditions (for example, below 0°C) (hereinafter sometimes referred to as "cooling expansion") is sometimes performed. However, when the conventional dicing die-bonding integrated film is applied to cooling expansion, it is sometimes difficult to separate the die-bonding film during cooling expansion. When the die-bonding film is not easy to separate, it becomes difficult to pick up the semiconductor chip with the die-bonding film sheet, and the yield in the manufacture of semiconductor devices may be reduced.

[0011] A main object of the present invention is to improve the cooling separation property of a die bonding film in a predetermined semiconductor device manufacturing method.

[0012] Means for solving technical problems

[0013] The present invention includes [1] to [6]. [1]

[0015] A cutting die bonding integrated film, comprising: a cutting film, including a base film and a pressure-sensitive adhesive layer provided on the base film, and an adhesive layer, arranged on the pressure-sensitive adhesive layer of the cutting film and formed by a die bonding film, wherein the loss tangent of the cutting film at 0°C is less than 0.15, and the loss tangent is a value obtained by a method including the following steps, wherein the steps are: preparing a measurement sample of the cutting film having a rectangular main surface with a short side of 5 mm and a long side of 8 mm; measuring the sample in a viscoelasticity measuring device (Rheogel-E4000, UBM) having a solid shearing fixture having a first plate-like component and a pair of second plate-like components Co., Ltd.), wherein two pieces of the measuring samples are arranged in a direction in which the main surface of the pressure-sensitive adhesive layer is in contact with the first plate-like member and in a manner in which the two measuring samples clamp the first plate-like member, and the measuring samples are respectively tightened from the thickness direction of the measuring samples by the pair of second plate-like members at a tightening pressure of 9 cN·m with a torque wrench, thereby fixing the measuring samples to the solid shearing fixture; and the loss tangent is determined by measuring the dynamic viscoelasticity of the shear mode of the solid shearing fixture to which the measuring samples are fixed, under the conditions of a measuring frequency of 10 Hz, a strain of 1% based on the total thickness of the cut film, and a heating rate of 2°C / min. [2]

[0017] The dicing die bonding integrated film according to [1], wherein:

[0018] The dicing film has a loss tangent of 0° C. or less. [3]

[0020] The dicing die bonding integrated film according to [1] or [2], wherein:

[0021] The pressure-sensitive adhesive layer has a thickness of 10 μm or less. [4]

[0023] A method for manufacturing a dicing die-bonding integrated film, comprising the following steps: selecting a dicing die including a substrate film and a pressure-sensitive adhesive layer disposed on the substrate film and having a loss tangent of less than 0.15 at 0°C; and bonding a die-bonding film to the pressure-sensitive adhesive layer of the dicing film, wherein the loss tangent is a value obtained by a method comprising the following steps: preparing a measurement sample of the dicing film having a rectangular main surface with a short side of 5 mm and a long side of 8 mm; measuring the sample in a viscoelasticity measuring device (Rheogel-E4000, UBM) having a solid shearing fixture having a first plate-like component and a pair of second plate-like components. Co., Ltd.), wherein two pieces of the measuring samples are arranged in a direction in which the main surface of the pressure-sensitive adhesive layer is in contact with the first plate-like member and in a manner in which the two measuring samples clamp the first plate-like member, and the measuring samples are respectively tightened from the thickness direction of the measuring samples by the pair of second plate-like members at a tightening pressure of 9 cN·m with a torque wrench, thereby fixing the measuring samples to the solid shearing fixture; and the loss tangent is determined by measuring the dynamic viscoelasticity of the shear mode of the solid shearing fixture to which the measuring samples are fixed, under the conditions of a measuring frequency of 10 Hz, a strain of 1% based on the total thickness of the cut film, and a heating rate of 2°C / min.

[0024] Effects of the Invention

[0025] According to the present invention, it is possible to improve the cooling interruption property of a die bonding film in a predetermined method for manufacturing a semiconductor device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic cross-sectional view showing one embodiment of a dicing film.

[0027] Figure 2 This is a schematic diagram for explaining a method for measuring the loss tangent of a diced film at 0°C.

[0028] Figure 3 It is a schematic cross-sectional view showing one embodiment of a dicing die bonding integrated film.

[0029] Figure 4 is a cross-sectional view schematically showing a method for manufacturing a semiconductor device, Figure 4 (a) Figure 4 (b) and Figure 4 (c) is a cross-sectional view schematically showing each step.

[0030] Figure 5 is a cross-sectional view schematically showing a method for manufacturing a semiconductor device, Figure 5 (a) and Figure 5 (b) is a cross-sectional view schematically showing each step. DETAILED DESCRIPTION

[0031] Hereinafter, the embodiments of the present invention will be described with appropriate reference to the accompanying drawings. However, the present invention is not limited to the following embodiments. In the following embodiments, except for the cases specifically indicated, the constituent elements (including the processes, etc.) are not essential. The sizes of the constituent elements in each figure are conceptual, and the relative relationship between the sizes of the constituent elements is not limited to the contents shown in each figure.

[0032] The numerical values ​​and their ranges in this specification are also similarly not intended to limit the present invention. In this specification, the numerical range represented by "~" represents a range in which the numerical values ​​before and after "~" are included as the minimum and maximum values, respectively. In the numerical ranges recorded in stages in this specification, the upper limit or lower limit recorded in one numerical range can be replaced by the upper limit or lower limit of other numerical ranges recorded in stages. Furthermore, in the numerical ranges recorded in this specification, the upper limit or lower limit of its numerical range can be replaced by the value shown in the embodiments.

[0033] In this specification, "(meth)acrylate" refers to at least one of acrylate and its corresponding methacrylate. The same applies to other similar expressions such as "(meth)acryloyl". Regarding "A or B", it only needs to contain any one of A and B, or both. Regarding the materials exemplified below, unless otherwise specified, one type may be used alone, or two or more types may be used in combination. When there are multiple substances that meet the requirements of each component in the composition, unless otherwise specified, the content of each component in the composition refers to the total amount of the multiple substances present in the composition.

[0034] [Cutting film]

[0035] Figure 1 This is a schematic cross-sectional view showing one embodiment of a dicing film (dicing tape). Figure 1 The dicing film 5 shown includes a base film 3 and a pressure-sensitive adhesive layer 2 provided on the base film 3. The base film 3 has, for example, a rectangular main surface. The main surface of the pressure-sensitive adhesive layer 2 may be a surface of the same size as the main surface of the die bonding film.

[0036] <Loss tangent (tanδ)>

[0037] The loss tangent of the dicing film (5) at 0°C was 0.15 or less. The loss tangent is the ratio of the loss modulus to the storage modulus. The loss tangent was measured using a dynamic viscoelasticity measuring device (Rheogel-E4000, manufactured by UBM Co., Ltd.) equipped with a solid shearing jig.

[0038] Figure 2 Schematic diagram for explaining the loss tangent measurement method. Two measuring samples 5A and 5B having a pressure-sensitive adhesive layer 2 and a base film 3 are fixed on a solid shearing jig 50. The solid shearing jig 50 has: a first plate-like member 51; and a pair of second plate-like members 52a and 52b. By fastening the measuring samples 5A and 5B in the thickness direction of the measuring samples 5A and 5B, that is, in the direction indicated by the directions d2 and d3, the measuring samples 5A and 5B can be fixed and can vibrate in the direction indicated by the direction d1. The first plate-like member 51 and the second plate-like members 52a and 52b can be plate-like members made of stainless steel (SUS). When the first plate-shaped part is fixed to the dynamic viscoelasticity measuring device and the measuring samples 5A, 5B are fixed to the solid shearing fixture 50 through the second plate-shaped parts 52a, 52b, the measuring samples 5A, 5B are vibrated in the direction indicated by the direction d1, thereby applying stress to the measuring samples 5A, 5B along the shear direction (direction d1).

[0039] The measuring samples 5A and 5B are arranged in a direction that the main surface of the pressure-sensitive adhesive layer 2 is in contact with the first plate-shaped member 51 and in a manner that the first plate-shaped member 51 is clamped. The measuring samples 5A and 5B are arranged in a direction that the main surface on the substrate film 3 side is in contact with the second plate-shaped members 52a and 52b, respectively. The measuring samples 5A and 5B are fixed to the solid shearing jig 50 by being fastened by a pair of second plate-shaped members 52a and 52b from directions d2 and d3. The main surface of the first plate-shaped member 51 in contact with the pressure-sensitive adhesive layer 2 can be the same or substantially the same size as the main surface of the pressure-sensitive adhesive layer 2 of the measuring samples 5A and 5B. The main surface of the second plate-shaped members 52a and 52b in contact with the substrate film 3 can be the same or substantially the same size as the main surface of the substrate film 3 of the measuring samples 5A and 5B.

[0040] As the measurement samples 5A and 5B, a diced film 5 of the measurement object having a rectangular main surface with a short side of 5 mm and a long side of 8 mm is used. The measurement samples 5A and 5B are samples made from the same diced film of the measurement object, and are made by cutting the diced film 5 of the measurement object as needed.

[0041] The measurement samples 5A and 5B are fixed to the solid shearing jig 50 in such a manner that the MD direction of the substrate film 3 is the short side and is the same direction as the direction d1 in which the solid shearing jig 50 vibrates. The measurement samples 5A and 5B are fixed to the solid shearing jig 50 in such a manner that the TD direction of the substrate film 3 is the long side and is orthogonal to the direction d1 in which the solid shearing jig 50 vibrates. The MD direction (Machine Direction) is a direction (flow direction) parallel to the long side direction in the original substrate film given to the substrate film 3. The TD direction (Transverse Direction) is a direction (vertical direction) orthogonal to the MD direction.

[0042] The measurement samples 5A and 5B are fixed to the solid shearing jig by being tightened from the thickness directions d2 and d3 by a pair of second plate-shaped members 52a and 52b under a tightening pressure of 9 cN·m with a torque wrench.

[0043] The measurement based on the dynamic viscoelasticity measuring device is carried out under the conditions of a measurement frequency of 10 Hz, a strain amount of 1% in terms of the total thickness ratio of the cut film, and a heating rate of 2°C / min. The measurement temperature range can be -20°C to 60°C. The loss tangent is obtained by dynamic viscoelasticity measurement in a shear mode using a solid shear fixture 50 to which the measurement samples 5A and 5B are fixed. The strain amount is the set value of the dynamic viscoelasticity measurement.

[0044] The loss tangent at 0°C is less than 0.15. When the loss tangent at 0°C is less than 0.15, the breaking property based on cooling and expansion is improved. The present inventors speculate that when the loss tangent is less than 0.15, the loss based on the fracture stress of the dicing film in cooling and expansion is sufficiently reduced, thereby increasing the stress transmitted to the grain bonding film, and as a result, the breaking property in the cooling and expansion process is improved, but the mechanism is not limited to this.

[0045] From the viewpoint of making it easier to obtain a dicing die bonding integrated film having excellent disengagement properties based on cooling expansion, the loss tangent at 0° C. may be 0.15 or less, 0.14 or less, 0.13 or less, 0.12 or less, 0.11 or less, 0.10 or less, 0.08 or less, 0.06 or less, or 0.04 or less. The loss tangent may be 0.01 or more or 0.02 or more.

[0046] The loss tangent at 0° C. can be controlled to fall within the above numerical range by adjusting the composition of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer (eg, pressure-sensitive adhesive composition, amount of cross-linking agent used, type and amount of initiator used, etc.).

[0047] From the viewpoint of economic efficiency and film handling properties, the thickness of the dicing film 5 (the total thickness of the base film 3 and the thickness of the pressure-sensitive adhesive layer 2 ) may be 60 to 150 μm or 70 to 130 μm.

[0048] <Pressure-sensitive adhesive layer>

[0049] The pressure-sensitive adhesive layer 2 may be a layer formed of a pressure-sensitive adhesive commonly used in dicing films. The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 2 may be an ultraviolet curing pressure-sensitive adhesive or a non-ultraviolet curing pressure-sensitive adhesive. An ultraviolet curing pressure-sensitive adhesive is a pressure-sensitive adhesive having a property of reducing adhesiveness by ultraviolet irradiation. By using an ultraviolet curing pressure-sensitive adhesive, for example, before picking up a semiconductor chip with a die bonding film attached, the adhesive strength of the pressure-sensitive adhesive layer 2 can be reduced by ultraviolet irradiation.

[0050] The ultraviolet curing pressure-sensitive adhesive may include, for example, an acrylic resin having a (meth)acryloyl group. The acrylic resin may include, for example, a hydroxyl group. The acrylic resin is a polymer containing a (meth)acrylate as a monomer unit. The ultraviolet curing pressure-sensitive adhesive may further include other components such as a photopolymerization initiator and a crosslinking agent (e.g., a polyisocyanate compound) as required. The crosslinking agent is a compound having a reactive group that reacts with the acrylic resin. As the crosslinking agent, for example, a polyisocyanate compound may be mentioned.

[0051] From the perspective of making it easier to obtain a dicing die bonding integrated film with excellent disengagement based on cooling and expansion, the thickness of the pressure-sensitive adhesive layer 2 can be 20 μm or less, 18 μm or less, 16 μm or less, 14 μm or less, 12 μm or less, 10 μm or less, 8 μm or less, 6 μm or less, 4 μm or less, or 2 μm or less. From the perspective of adhesion during cooling and expansion and adhesion to the dicing ring, the thickness of the pressure-sensitive adhesive layer 2 can be, for example, 1 μm or more, 3 μm or more, or 5 μm or more. The thickness of the pressure-sensitive adhesive layer 2 can be, for example, 1 to 10 μm.

[0052] The ratio of the thickness (unit: μm) of the pressure-sensitive adhesive layer 2 to the thickness (unit: μm) of the substrate film 3 may be less than 1, 1 / 2 or less, 1 / 3 or less, 1 / 4 or less, 1 / 6 or less, 1 / 8 or less, 1 / 10 or less, or 1 / 15 or less. The ratio of the thickness (unit: μm) of the pressure-sensitive adhesive layer 2 to the thickness (unit: μm) of the substrate film 3 may be 1 / 150 or more, 1 / 125 or more, 1 / 100 or more, 1 / 75 or more, or 1 / 50 or more.

[0053] The thickness (unit: μm) of the pressure-sensitive adhesive layer 2 can be less than 1, less than 1 / 2, less than 1 / 4, less than 1 / 6, less than 1 / 8, less than 1 / 10 or less than 1 / 15 relative to the thickness (unit: μm) of the dicing film 5, and can be greater than 1 / 100, greater than 1 / 75 or greater than 1 / 50.

[0054] <Base film>

[0055] The resin constituting the substrate film 3 may include single polymers of olefins such as ethylene, propylene, butene, hexene, methylpentene, 4-methyl-1-pentene, vinyl acetate, and copolymers thereof; polyethylene terephthalate, polyethylene naphthalate, Polyesters such as polynaphthalate; ethylene copolymers such as ethylene-vinyl acetate copolymers, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, and ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymers; ionomer resins having an ion-crosslinked structure by forming salts between an acid component and a metal ion (sodium ion, zinc ion, etc.) in a copolymer containing an olefin such as ethylene and (meth)acrylic acid; engineering plastics such as polycarbonate, polyamide, polyimide, polyetheretherketone, polyetherimide, wholly aromatic polyamide, and polyphenylene sulfide; aramid (paper); glass; glass cloth; fluorine resins; chlorine resins such as polyvinyl chloride and polyvinylidene chloride; cellulose resins; silicone resins; or mixtures obtained by mixing these with plasticizers or cured products crosslinked by electron beam irradiation. The substrate film may be composed of a single resin or a mixed resin obtained by mixing two or more resins. In addition, the substrate film may be a film having a laminated structure in which two or more films are laminated. From the viewpoint of controlling the adhesion with the pressure-sensitive adhesive layer 2, the substrate film may be subjected to a surface roughening treatment such as a matte treatment or a corona treatment. The substrate film 3 may be a substrate film containing at least one resin selected from the group consisting of polyester, ethylene copolymer, ion crosslinked polymer resin and engineering plastic.

[0056] The substrate film 3 can be made by making a film using a conventionally known method. For example, the resin composition obtained by adding additives such as an antistatic agent to the resin raw material of the substrate as needed and melt-mixing can be processed into a film-like shape by using various molding methods such as T-die die casting, T-die nip molding, expansion molding, extrusion lamination, and calendering molding. In addition, when the substrate film has a laminated structure, the laminated structure can be made by laminating each layer using methods such as calendering molding, extrusion, and expansion molding, etc., and laminating them using methods such as thermal lamination or bonding based on adhesives. As an adhesive, an adhesive commonly used when making a laminated structure can be used. In addition, the laminated structure can also be made by simultaneously extruding the resin composition of each layer by co-extrusion lamination. Furthermore, for the purpose of stabilizing winding when manufacturing the base film 3 and preventing blocking after film formation, the surface of the base film opposite to the surface in contact with the pressure-sensitive adhesive layer may be embossed using an embossing roll.

[0057] From the viewpoint of being able to more easily obtain a dicing die bonding integrated film having excellent disengagement properties based on cooling expansion, the thickness of the base film 3 may be 20 μm or more, 30 μm or more, 40 μm or more, 50 μm or more, 60 μm or more, 70 μm or more, or 80 μm or more. From the viewpoint of being economically advantageous, the thickness of the base film 3 may be 200 μm or less, 150 μm or less, 130 μm or less, 110 μm or less, 100 μm or less, or 90 μm or less. The thickness of the base film 3 may be, for example, 30 to 150 μm, or 30 to 90 μm.

[0058] The shape of the substrate film 3 may have a rectangular main surface, but is not limited thereto. The substrate film 3 may be a long film, and for example, a plurality of pressure-sensitive adhesive layers 2 may be disposed on a single long substrate film 3 .

[0059] <Method for producing dicing film>

[0060] The dicing film 5 can be produced, for example, by a method including a step (selection step) of selecting a dicing film having a loss tangent of 0.15 or less at 0° C. as described above.

[0061] [Dicing and Die Bonding Integrated Film]

[0062] Figure 3 The dicing die bonding integrated film 10 includes a die bonding film 1 (hereinafter sometimes referred to as an "adhesive layer") and a dicing film 5 having a pressure-sensitive adhesive layer 2 bonded to the die bonding film 1.

[0063] The die-bonding film 1 is an adhesive film for bonding a semiconductor chip to a substrate or another semiconductor chip, and is sometimes referred to as a die attach film (DAF). The die-bonding film 1 has, for example, a circular main surface that covers the entire main surface of a semiconductor wafer.

[0064] The thickness of the grain bonding film 1 (adhesive layer) can be, for example, less than 150 μm, less than 120 μm, less than 100 μm, less than 70 μm, less than 60 μm, less than 50 μm, less than 40 μm, less than 30 μm, less than 25 μm or less than 20 μm, and can be greater than 3 μm, greater than 5 μm, greater than 7 μm or greater than 10 μm.

[0065] The die bonding film 1 may be a film formed of an adhesive generally used for bonding semiconductor chips. The die bonding film 1 may be a thermosetting adhesive. The thermosetting adhesive constituting the die bonding film 1 contains, for example, a thermosetting component and a high molecular weight resin component (elastomer).

[0066] The thermosetting component is a compound (resin) having a reactive group that forms a cross-linked structure by self-polymerization and / or reaction with a curing agent. The thermosetting component may include, for example, an epoxy resin, and in addition to the epoxy resin, may also include a phenolic resin that acts as a curing agent for the epoxy resin. The content of the thermosetting component may be 5 to 250 parts by mass relative to 100 parts by mass of the total amount of the die bonding film.

[0067] The high molecular weight resin component (elastomer) may include, for example, at least one resin selected from the group consisting of acrylic rubber, polyimide and phenoxy resin, and may also include acrylic rubber. The high molecular weight resin component may have a reactive group such as an epoxy group. The weight average molecular weight (based on the standard polystyrene conversion value of the GPC method) of the high molecular weight resin component may be 100,000 to 3,000,000. The content of the high molecular weight resin component may be 30 to 80 parts by mass relative to the total amount of 100 parts by mass of the die bonding film.

[0068] The thermosetting adhesive may contain other components as necessary. Examples of other components include a curing accelerator that accelerates the reaction between the epoxy resin and the phenolic resin, a coupling agent (eg, a silane coupling agent), and an inorganic filler (eg, silica).

[0069] The dicing die-bonding integrated film can be preferably used in a method for manufacturing a semiconductor device including the step of forming semiconductor chips with die-bonding film sheets by expanding the dicing film under cooling conditions (eg, 0° C. or less) to separate the die-bonding film.

[0070] <Method for manufacturing dicing die bonding integrated film>

[0071] The dicing die bonding integrated film 10 can be manufactured by a method including a step of bonding a die bonding film and the pressure-sensitive adhesive layer 2 of the dicing film 5 , for example.

[0072] [Method for manufacturing semiconductor device]

[0073] Figure 4 and Figure 5 : is a cross-sectional view schematically showing a method for manufacturing a semiconductor device. The method for manufacturing a semiconductor device includes the following steps: (A) preparing a stacked body 40 having a dicing die bonding integrated film 10 and a plurality of semiconductor chips C, wherein the dicing die bonding integrated film 10 has a dicing film 5 having a base film 3 and a pressure-sensitive adhesive layer 2 provided on the base film 3, and a die bonding film 1 provided on the pressure-sensitive adhesive layer 2, wherein the plurality of semiconductor chips C are provided on the die bonding film 1 of the dicing die bonding integrated film 10 and are obtained by singulating the semiconductor chips; and (B) preparing a semiconductor chip 30 with a die bonding film sheet having semiconductor chips C and a die bonding film sheet 1a obtained by singulating the die bonding film 1 by expanding the dicing film 5 of the stacked body 40 under cooling conditions. The method for manufacturing a semiconductor device may further include the following steps: (C) picking up the semiconductor chip 30 with a die-bonding film from the pressure-sensitive adhesive layer 2; and (D) mounting the picked-up semiconductor chip 30 with a die-bonding film on a substrate or another semiconductor chip.

[0074] The semiconductor chip C is formed by singulating a semiconductor wafer. The semiconductor wafer may be a silicon wafer, and the semiconductor chip C may be a silicon chip. The semiconductor chip C has a main surface F1 and a main surface F2, for example, the main surface F1 may be a circuit surface (front surface) and the main surface F2 may be a back surface opposite to the circuit surface.

[0075] Regarding the thickness of the semiconductor wafer, for example, a wafer having a thickness of 8 inches or 12 inches can be used.

[0076] The method of singulating the semiconductor wafer may be a stealth dicing method such as an SDBG (Stealth Dicing Before Grinding) method or a half cut dicing method such as a DBG (Dicing Before Grinding) method.

[0077] The stealth cutting method, for example, can be a method including the following steps: attaching a protective tape (back grinding tape) on the circuit surface of a semiconductor wafer; forming a modified area inside the semiconductor wafer by irradiating laser light; and grinding the semiconductor wafer from the back side, using the modified area as a starting point for cutting the semiconductor wafer.

[0078] The half-cut method, for example, may be a method comprising the following steps: forming a groove on the surface of a semiconductor wafer by a cutting blade; attaching a protective tape (back grinding tape) to the circuit surface of the semiconductor wafer; and grinding from the back side of the semiconductor wafer to the groove.

[0079] By using this method of singulating a semiconductor wafer, a stacked body 20 (see FIG. 1 ) including a protective tape 7 (back grinding tape) and a plurality of semiconductor chips C disposed on the protective tape 7 can be obtained. Figure 4 (a) In the laminated body 20 , the semiconductor chip C is provided on the protective tape 7 .

[0080] The thickness of the semiconductor chip C is smaller than that of the semiconductor wafer, and may be, for example, 10 to 200 μm. The thickness of the semiconductor chip C may be 15 μm or more or 20 μm or less, and 150 μm or less, 100 μm or less, or 50 μm or less.

[0081] Next, the die bonding film 1 of the diced die bonding integrated film 10 is attached to the semiconductor chip C (see FIG. 1 ) under heating conditions in such a direction that the die bonding film 1 is in contact with the main surface F2 of the semiconductor chip C. Figure 4 (a)). The temperature of the heating condition can be, for example, 40 to 80°C. Thus, a stack 40 of a plurality of semiconductor chips C obtained by singulating a semiconductor wafer and having a diced die bonding integrated film 10 and a die bonding film 1 disposed on the diced die bonding integrated film 10 can be obtained. The die bonding film 1 is attached to the semiconductor chip C, and a dicing ring DR is attached to the main surface 2b of the die bonding film 1 side of the pressure-sensitive adhesive layer 2 in a manner that surrounds the plurality of semiconductor chips C (refer to Figure 4 (b)) When the laminated body 40 is bonded to the semiconductor chip C, the laminated body 40 may include a dicing ring DR on the main surface 2b of the pressure-sensitive adhesive layer 2 on the die bonding film 1 side. In addition, the protective tape 7 is peeled off from the semiconductor chip C at an appropriate time.

[0082] Next, under cooling conditions, the area inside the dicing ring DR of the dicing film 5 is pushed up using the ring Ra, thereby expanding (stretching) the dicing film 5 (reference Figure 4 (c)). The temperature of the cooling condition may be, for example, -15 to 0°C. The die bonding film 1 is cut by expanding the dicing film 5. By this cutting, a semiconductor chip 30 with a die bonding film sheet is formed on the pressure-sensitive adhesive layer 2, which includes a semiconductor chip C and a die bonding film sheet 1a obtained by singulating the die bonding film 1.

[0083] After the ring Ra is removed, the area between the dicing ring DR and the semiconductor chip 30 with the die-bonding film attached in the dicing film 5 (reference Figure 5(a) Heating is performed. Due to the heat contraction of the dicing film 5 in the heated portion, the kerf width between the semiconductor chips 30 with the die-bonding film tends to be further expanded.

[0084] When the pressure-sensitive adhesive layer 2 is a layer formed of an ultraviolet curing pressure-sensitive adhesive, the adhesive strength of the pressure-sensitive adhesive layer 2 can be reduced by ultraviolet irradiation. After the adhesive strength of the pressure-sensitive adhesive layer 2 is reduced, the semiconductor chips 30 with die-bonding films pushed out by the push-up jig 42 are picked up by the suction chuck 44 (refer to Figure 5 (b)).

[0085] The semiconductor chip 30 with the die-bonding film thus picked up is mounted on a substrate or another semiconductor chip. By stacking a plurality of semiconductor chips, for example, a 3D NAND flash memory can be manufactured.

[0086] Example

[0087] Hereinafter, the present invention will be specifically described based on Examples, but the present invention is not limited to these.

[0088] Example 1

[0089] 1-1. Preparation of pressure-sensitive adhesive layer (Production Example A-1)

[0090] A copolymer of the following monomers, namely, acrylic polymer 1 was prepared. The weight average molecular weight (Mw) of acrylic polymer 1 was 910,000, the number average molecular weight (Mn) was 140,000, and Mw / Mn was 6.5. The hydroxyl value of acrylic polymer 1 was 2.5 mgKOH / g.

[0091] Butyl acrylate: 88.1 parts by mass

[0092] 2-Hydroxyethyl methacrylate: 0.6 parts by mass

[0093] Acrylonitrile: 11.2 parts by mass

[0094] Coronate L38ET (manufactured by Tosoh Corporation, TMP adduct of toluene diisocyanate, Nv37.5N, TDI adduct, trifunctional NCO% 6.6%) as a crosslinking agent was mixed in the following ratio, i.e., 2.2 parts by mass in terms of solid content relative to 100 parts by mass of the acrylic polymer 1, and the mixture was diluted with methyl ethyl ketone (MEK) and stirred to prepare a pressure-sensitive adhesive solution A-1.

[0095] The pressure-sensitive adhesive solution A-1 was applied to a polyethylene terephthalate film (thickness 38 μm) subjected to a release treatment on one side to a thickness of 10 μm after drying, and dried at 80° C. for 3 minutes to form a pressure-sensitive adhesive layer of Production Example A-1 on the polyethylene terephthalate film.

[0096] 1-2. Preparation of substrate film (Production Example B-1)

[0097] Based on Zn 2+ Neutralization degree of ions: 60 mol%, melting point: 86°C, MFR: 1 g / 10 min (190°C / 2.16 kg load), density: 0.96 g / cm 3 A terpolymer of a resin having a mass ratio of ethylene / methacrylic acid / 2-methyl-propyl acrylate=80 / 10 / 10 was formed into a film having a thickness of 90 μm and the produced film was used as the base film of Production Example B-1.

[0098] 1-3. Preparation of cutting film

[0099] A base film (Manufacture Example B-1) having one surface subjected to a corona discharge treatment was bonded to the pressure-sensitive adhesive layer of Manufacture Example A-1. The bonded sample was aged in a thermostatic chamber at 23°C for 96 hours to produce a dicing film.

[0100] 1-4. Preparation of Adhesive Layer (Production Example C-1)

[0101] 100 parts by weight of HTR-860P-3 (product name, manufactured by Nagase ChemteX Corporation, glycidyl-containing acrylic rubber, molecular weight 1 million, Tg -7°C), 20 parts by weight of YDCN-700-10 (product name, manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD., o-cresol novolac type epoxy resin, epoxy equivalent 210), 17 parts by weight of Milex XLC-LL (product name, manufactured by Mitsui Chemicals, Inc., phenol aralkyl resin), 0.04 parts by weight of 1-(2-cyanoethyl)-2-phenylimidazole (2PZ-CN), 12 parts by weight of AEROSIL R972 (product name, manufactured by NIPPON AEROSIL CO., LTD., silica, average particle size 0.016 μm), and 12 parts by weight of A-189 (product name, manufactured by NIPPON UNICAR CO., LTD., γ-mercaptopropyltrimethoxysilane) 0.6 parts by weight, A-1170 (NIPPON UNICAR CO., LTD., γ-ureidopropyltriethoxysilane) 1.7 parts by weight, and vacuum degassed. The adhesive varnish was applied on a 75 μm thick surface release treated polyethylene terephthalate (Teijin DuPont Films Co., Ltd., Teijin Tetoron Films: A-31) to obtain a 20 μm thick adhesive layer (die bonding film).

[0102] 1-5. Preparation of Dicing and Bonding Integrated Film (Example 1)

[0103] The adhesive layer (die bonding film) and the dicing film were bonded together so that the adhesive layer of the die bonding film came into contact with the pressure-sensitive adhesive layer of the dicing film, thereby obtaining a dicing die bonding integrated film of Example 1.

[0104] Example 2

[0105] 2-1. Preparation of pressure-sensitive adhesive layer (Production Example A-2)

[0106] The following monomer copolymer, namely, acrylic polymer 2 was prepared. The weight average molecular weight (Mw) of acrylic polymer 2 was 610,000, the number average molecular weight (Mn) was 140,000, and Mw / Mn was 4.4. The hydroxyl value of acrylic polymer 2 was 19.5 mgKOH / g.

[0107] Butyl acrylate: 71.2 parts by mass

[0108] ·2-Hydroxyethyl methacrylate: 4.8 parts by mass

[0109] Acrylonitrile: 24.0 parts by mass

[0110] The following ratios were used: 70 parts by mass of acrylic polymer 1, 30 parts by mass of acrylic polymer 2, and 2.2 parts by mass of Coronate L38ET (manufactured by Tosoh Corporation, TMP adduct of toluene diisocyanate, Nv 37.5%, TDI adduct trifunctional NCO 6.6%) as a crosslinking agent, and the mixture was diluted with methyl ethyl ketone (MEK) and stirred to prepare a pressure-sensitive adhesive solution A-2. The pressure-sensitive adhesive layer of Manufacturing Example A-2 was prepared in the same manner as Manufacturing Example A-1 except that the pressure-sensitive adhesive solution A-2 was used instead of the pressure-sensitive adhesive solution A-1.

[0111] 2-2. Preparation of Dicing and Bonding Integrated Film (Example 2)

[0112] A dicing die bonding integrated film of Example 2 was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive layer of Production Example A-2 was used as the pressure-sensitive adhesive layer.

[0113] Comparative Example 1

[0114] 3-1. Preparation of pressure-sensitive adhesive layer (Production Example A-3)

[0115] As comonomer components, 2-ethylhexyl acrylate (EHA), 2-hydroxyethyl acrylate (HEA) and methyl methacrylate (MMA) were prepared. These comonomer components were mixed in a copolymerization ratio of EHA / HEA / MMA = 78 parts by mass / 21 parts by mass / 1 part by mass, ethyl acetate was used as a solvent, and 0.08 parts by mass of azobisisobutyronitrile (AIBN) was used as an initiator, and an acrylic copolymer was obtained by solution free radical polymerization. For the acrylic copolymer, 0.05 parts by mass of hydroquinone monomethyl ether (Hydroquinone Monomethyl Ether) was used as a polymerization inhibitor, and 16 parts by mass of 2-isocyanatoethyl methacrylate (product name: Karenz MOI, molecular weight: 155.15) was reacted to synthesize a UV-curable pressure-sensitive adhesive with a carbon-carbon double bond. The weight average molecular weight of the obtained UV-curable pressure-sensitive adhesive is 350,000. The hydroxyl value and acid value of the ultraviolet curable pressure-sensitive adhesive were 37.6 mgKOH / g and 6.5 mgKOH / g, respectively. The obtained ultraviolet curable pressure-sensitive adhesive was mixed in the following ratios: 100 parts by mass of the obtained ultraviolet curable pressure-sensitive adhesive in terms of solid content, 1.0 parts by mass of an α-hydroxyalkylphenone photopolymerization initiator (product name: Omnirad184) manufactured by IGM Resins BV, 0.2 parts by mass of an acylphosphine oxide photopolymerization initiator (product name: Omnirad819) manufactured by IGM Resins B.V., and 2.07 parts by mass of a TDI polyisocyanate crosslinking agent (product name: Coronate L-45E) manufactured by Tosoh Corporation as a crosslinking agent in terms of solid content, diluted with ethyl acetate, and stirred to prepare a pressure-sensitive adhesive solution A-3. A pressure-sensitive adhesive layer of Production Example A-3 was produced by the same method as in Production Example A-1, except that pressure-sensitive adhesive solution A-3 was used instead of pressure-sensitive adhesive solution A-1.

[0116] 3-2. Preparation of Dicing and Bonding Integrated Film (Comparative Example 1)

[0117] A dicing die bonding integrated film of Comparative Example 1 was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive layer of Production Example A-3 was used as the pressure-sensitive adhesive layer.

[0118] Comparative Example 2

[0119] 4-1. Preparation of pressure-sensitive adhesive layer (Production Example A-4)

[0120] The following ratios were prepared: 100 parts by mass of the ultraviolet curable pressure-sensitive adhesive prepared in Preparation Example A-3, 1.0 parts by mass of an α-hydroxyalkylphenone photopolymerization initiator (product name: Omnirad184) manufactured by IGM Resins BV, 0.2 parts by mass of an acylphosphine oxide photopolymerization initiator (product name: Omnirad819) manufactured by IGM Resins BV, and 4.14 parts by mass of a TDI-based polyisocyanate crosslinking agent (product name: Coronate L-45E) manufactured by Tosoh Corporation as a crosslinking agent, diluted with ethyl acetate, and stirred to prepare a pressure-sensitive adhesive solution A-4. A pressure-sensitive adhesive layer of Preparation Example A-4 was prepared in the same manner as Preparation Example A-1 except that the pressure-sensitive adhesive solution A-4 was used instead of the pressure-sensitive adhesive solution A-1.

[0121] 4-2. Preparation of Dicing and Bonding Integrated Film (Comparative Example 2)

[0122] A dicing die bonding integrated film of Comparative Example 1 was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive layer of Production Example A-4 was used as the pressure-sensitive adhesive layer.

[0123] Embodiments 3 to 5

[0124] 5-1. Preparation of pressure-sensitive adhesive layer (Production Example A-5)

[0125] As a copolymerization monomer component, the copolymerization ratio of EHA / HEA / MMA=78 parts by mass / 21 parts by mass / 1 part by mass was set, and 19 parts by mass of 2-isocyanatoethyl methacrylate (product name: Karenz MOI, molecular weight: 155.15) was reacted. In addition, a UV-curable pressure-sensitive adhesive was synthesized by the same method as the preparation of the UV-curable pressure-sensitive adhesive in Comparative Example 1. The weight average molecular weight of the obtained UV-curable pressure-sensitive adhesive was 350,000. The hydroxyl value and acid value of the obtained UV-curable pressure-sensitive adhesive were 27.5 mgKOH / g and 6.5 mgKOH / g, respectively. Using the obtained UV-curable pressure-sensitive adhesive and changing the thickness of the pressure-sensitive adhesive layer to the thickness shown in Table 2, the pressure-sensitive adhesive layer of Manufacturing Example A-5 was prepared in the same manner as Manufacturing Example A-1.

[0126] 5-2. Preparation of Dicing and Bonding Integrated Film (Examples 3 to 5)

[0127] Dicing die bonding integrated films of Examples 3 to 5 were prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive layer of Production Example A-5 was used as the pressure-sensitive adhesive layer and the thickness of the adhesive layer of Production Example C-1 was changed to 7 μm.

[0128] 6. Evaluation

[0129] <Measurement of hydroxyl value and acid value>

[0130] The hydroxyl value was measured according to the method described in JIS K0070: 1992. The acid value was measured according to the method described in JIS K2501: 2003.

[0131] <Measurement of weight average molecular weight and number average molecular weight>

[0132] The weight average molecular weight and number average molecular weight are values ​​calculated in terms of standard polystyrene by the GPC method. The details of the measurement conditions are as follows.

[0133] GPC measurement was performed using SD-8022 / DP-8020 / RI-8020 manufactured by Tosoh Corporation, Gelpack GL-A150-S / GL-A160-S manufactured by Hitachi Chemical Company, Ltd. as a column, and tetrahydrofuran as an eluent.

[0134] <Measurement of loss tangent>

[0135] As a sample for measurement, a diced film having a rectangular main surface with a short side of 5 mm and a long side of 8 mm was prepared. Figure 2 As shown, the sample for measurement was arranged on a solid shearing fixture, and the MD direction (Machine Direction: the direction parallel to the long side direction (flow direction) in the original substrate film given to the substrate film) of the substrate film was fixed as the short side. Viscoelasticity measurement was performed under the following apparatus and measurement conditions, and the loss tangent at 0°C (0°C tanδ) was obtained.

[0136] [Device information]

[0137] Rheogel-E4000 manufactured by UBM Co., Ltd. "Dynamic Viscoelasticity Measurement Device (DMA)"

[0138] [Measurement conditions]

[0139] Measuring fixture: Solid shear fixture M039

[0140] Frequency: 10Hz

[0141] Sine wave

[0142] ·Strain (amount of strain): 1% based on the total thickness ratio

[0143] Sample size: 5×8mm

[0144] Heating rate: 2℃ / min

[0145] Tightening pressure: torque wrench 9cN·m

[0146] <Discontinuity evaluation>

[0147] [Preparation of Evaluation Samples]

[0148] The evaluation samples were prepared according to the following process. A protective tape was attached to the surface of a silicon wafer (diameter: 12 inches, thickness: 775 μm). Thereafter, the silicon wafer was singulated by stealth dicing. That is, a modified region was formed inside the silicon wafer by irradiating the surface (back side) of the silicon wafer on the opposite side to the side with the protective tape attached with laser light under the following conditions.

[0149] (Stealth cutting conditions)

[0150] Stealth cutting device: DFL7361 (manufactured by DISCO Corporation)

[0151] Laser oscillator type: semiconductor laser pumped Q-switched solid-state laser

[0152] Wavelength: 1342nm

[0153] Frequency: 60kHz

[0154] Output: 0.8W

[0155] Number of paths: 2

[0156] Chip size: 3mm×12mm

[0157] Cutting speed: 800mm / sec

[0158] Next, a grinding and polishing device (DGP8761, manufactured by DISCO Corporation) is used to grind (polish) the surface of the silicon wafer on the side opposite to the protective tape until the thickness of the silicon wafer becomes 30 μm, and the silicon wafer is singulated to obtain a silicon chip. Under the following attachment conditions, the die bonding film of the diced die bonding integrated film is attached to the surface of the silicon chip on the side opposite to the protective tape. At this time, the attachment direction is adjusted in such a way that the direction of the dividing line of the silicon chip is along the MD direction and TD direction (Transverse Direction: lateral direction, direction orthogonal to the MD direction (vertical direction)) of the substrate film of the diced die bonding integrated film. In addition, the wafer is attached in such a way that the long side of the chip is perpendicular to the MD direction. Moreover, the pressure-sensitive adhesive layer of the portion overflowing from the die bonding film is attached to the dicing ring, and thereafter, the protective tape is peeled off from the silicon wafer.

[0159] (Attachment conditions)

[0160] Attachment device: DFM2800 (manufactured by DISCO Corporation)

[0161] Attachment temperature: 65℃

[0162] Attachment speed: 10mm / s

[0163] ·Attachment tension level: Level 5

[0164] Next, a die dividing machine (DDS2300, manufactured by DISCO Corporation) was used to extend the dicing film for dicing the die-bonding integrated film by cooling and expanding under the following cooling and expanding conditions, thereby dividing the die-bonding film.

[0165] (Cooling extension conditions)

[0166] Cooling temperature: 0℃

[0167] Cooldown: 120 seconds

[0168] ·Push up amount: 8mm

[0169] Pushing speed: 120mm / sec

[0170] Hold time after push-up: 10 seconds

[0171] [Discontinuity evaluation]

[0172] The samples after the grain bonding film was divided by cooling and expansion were evaluated for the splitting property by the following procedure. The results are shown in Tables 1 and 2.

[0173] Using a measuring microscope (MF-U) manufactured by Mitutoyo Corporation, the chips were magnified and observed from above along the long side (12 mm) of the chip and along the short side (3 mm) of the chip to confirm the disconnection state of the grain bonding film. 216 locations on the long side and 216 locations on the short side of the chip (total number of observations: 432) were used as observation objects. The long side and short side of the chip as the observation object were selected from one side of the chip (216 locations on the long side, 216 locations on the short side, a total of 432 locations) formed by dividing by any one of the dividing lines in the 3rd, 8th, 13th, 18th and 23rd columns of the 26 columns of dividing lines along the direction of the short side of the chip. If the entire grain bonding film edge is cut off, it is judged as OK. If the entire or part of the edge is not cut off and remains, it is judged as NG. The disconnection property was evaluated based on the disconnection NG rate calculated using the formula: (NG number / total number of observations) × 100. The case where the discontinuity NG rate was 1% or less was evaluated as "A", the case where it was more than 1% and 3% or less was evaluated as "B", and the case where it was more than 3% was evaluated as "C".

[0174] [Table 1]

[0175]

[0176] [Table 2]

[0177]

[0178] As shown in Tables 1 and 2, the dicing die bonding integrated films of Examples 1 to 5 having a tan δ at 0°C of 0.15 or less were superior in breaking properties compared to the dicing die bonding integrated films of Comparative Examples 1 and 2 having a tan δ at 0°C of more than 0.15.

[0179] From the above, it was confirmed that according to the present invention, the cooling separation property of the die bonding film can be improved in a predetermined method for manufacturing a semiconductor device.

[0180] Explanation of symbols

[0181] 1-die bonding film, 1a-die bonding film sheet, 2-pressure-sensitive adhesive layer, 3-base film, 5-cutting film, 5A, 5B-measurement samples, 7-protective tape, 10-cutting die bonding integrated film, 30-semiconductor chip with die bonding film sheet, 50-solid shearing fixture, 51-first plate-shaped component, 52a, 52b-second plate-shaped components, C-semiconductor chip.

Claims

1. A dicing die bonding integrated film, comprising: A cutting film, comprising a substrate film and a pressure-sensitive adhesive layer disposed on the substrate film; and an adhesive layer disposed on the pressure-sensitive adhesive layer of the dicing film and formed of a die bonding film, The loss tangent of the dicing film at 0°C is less than 0.15, The loss tangent is a value obtained by a method including the following steps: A measurement sample of the diced film having a rectangular main surface with a short side of 5 mm and a long side of 8 mm is prepared; In a viscoelasticity measuring device having a solid shearing fixture having a first plate-like member and a pair of second plate-like members, namely, a Rheogel-E4000 viscoelasticity measuring device manufactured by UBM Co., Ltd., two sheets of the measuring samples are arranged in a direction in which the main surface of the pressure-sensitive adhesive layer is in contact with the first plate-like member and in a manner in which the first plate-like member is sandwiched by the two sheets of the measuring samples, and the measuring samples are respectively tightened from the thickness direction of the measuring samples by the pair of second plate-like members under a tightening pressure of 9 cN·m with a torque wrench, thereby fixing the measuring samples to the solid shearing fixture; and The loss tangent is determined by dynamic viscoelasticity measurement in a shear mode using the solid shear jig to which the measurement sample is fixed, under conditions of a measurement frequency of 10 Hz, a strain amount of 1% based on the total thickness ratio of the diced film, and a heating rate of 2° C. / min.

2. The dicing die bonding integrated film according to claim 1, wherein: The loss tangent at 0° C. is 0.07 or less.

3. The dicing die bonding integrated film according to claim 1 or 2, wherein: The pressure-sensitive adhesive layer has a thickness of 10 μm or less.

4. A method for manufacturing a dicing die bonding integrated film, comprising the following steps: Selecting a cutting mold including a substrate film and a pressure-sensitive adhesive layer disposed on the substrate film and having a loss tangent of 0.15 or less at 0° C.; and bonding a die bonding film to the pressure-sensitive adhesive layer of the dicing film, The loss tangent is a value obtained by a method including the following steps: A measurement sample of the diced film having a rectangular main surface with a short side of 5 mm and a long side of 8 mm is prepared; In a viscoelasticity measuring device having a solid shearing fixture having a first plate-like member and a pair of second plate-like members, namely, a Rheogel-E4000 viscoelasticity measuring device manufactured by UBM Co., Ltd., two sheets of the measuring samples are arranged in a direction in which the main surface of the pressure-sensitive adhesive layer is in contact with the first plate-like member and in a manner in which the first plate-like member is sandwiched by the two sheets of the measuring samples, and the measuring samples are respectively tightened from the thickness direction of the measuring samples by the pair of second plate-like members under a tightening pressure of 9 cN·m with a torque wrench, thereby fixing the measuring samples to the solid shearing fixture; and The loss tangent is determined by dynamic viscoelasticity measurement in a shear mode using the solid shear jig to which the measurement sample is fixed, under conditions of a measurement frequency of 10 Hz, a strain amount of 1% based on the total thickness ratio of the diced film, and a heating rate of 2° C. / min.

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