Multilayer film for film base material of semiconductor manufacturing process film, and semiconductor manufacturing process film

Abstract

To provide a multilayered film suitable as the film base material of a semiconductor manufacturing process film substituted for the film of a soft polyvinyl chloride resin composition to fundamentally solve the problem caused by a plasticizer, and the semiconductor manufacturing process film using the multilayered film as a film base material.SOLUTION: A multilayer film for a film base material of a semiconductor process film, in which (α 1) a first polyolefin layer, (β) an elastomer layer, and (α 2) a second polyolefin layer are directly laminated in this order, the (α 1) first polyolefin layer includes polyethylene or polypropylene, the (β) elastomer layer includes a hydrogenated product of a block copolymer of an aromatic vinyl compound and a conjugated diene compound, and the (α 2) second polyolefin layer includes polyethylene or polypropylene.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a multilayer film suitable as a film substrate for a film in a semiconductor manufacturing process, and to a film in a semiconductor manufacturing process using the multilayer film as a film substrate. [Background technology]

[0002] Semiconductor chips are produced by forming a large number of chips together on a large-diameter silicon wafer, polishing the silicon wafer from its backside (the side opposite to the side on which circuits are formed (circuit side)) to the desired thickness, and then dicing (cutting and separating) into individual semiconductor chips. The silicon wafer polishing process is often performed after laminating an adhesive film (hereinafter referred to as a "backgrinding film") to the circuit side of the silicon wafer for the purpose of protecting the circuit side of the silicon wafer. The dicing process into individual semiconductor chips is often performed after laminating an adhesive film (hereinafter referred to as a "dicing film") on the circuit side and / or backside of the silicon wafer for the purpose of protecting the surface of the semiconductor chips and fixing and picking up the individual cut semiconductor chips. An adhesive film (hereinafter referred to as a "die attach film") that is imparted to the dicing film with the function of adhesively laminating and mounting semiconductor chips on a substrate is also often used. As such, many types of process films are used in the semiconductor manufacturing process.

[0003] Traditionally, films made of flexible polyvinyl chloride resin compositions have been widely used as film substrates for semiconductor manufacturing processes because of their many advantages, including tensile properties suitable for the expanding process (a process in which, after cutting a silicon wafer, the dicing film is pulled to increase the distance between individual semiconductor chips and facilitate their pickup); a well-balanced heat resistance and flexibility; high transparency; and low cost. However, films made of flexible polyvinyl chloride resin compositions contain large amounts of plasticizer, which can migrate into the adhesive, destabilizing the adhesive properties (reducing or increasing adhesive strength); and the plasticizer can contaminate semiconductor chips and other components. Therefore, polyolefin resin films have been proposed as film substrates for semiconductor manufacturing processes (e.g., Patent Documents 1 to 3). However, previous polyolefin resin films have not performed as well as films made of flexible polyvinyl chloride resin compositions in terms of their performance as film substrates for semiconductor manufacturing processes. In particular, when polyolefin resin films are intended to be given sufficient flexibility and expandability (tensile properties suitable for the expanding process), they have the disadvantage of being insufficient in terms of blocking resistance and heat resistance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-065327 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-232683 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-162787 [Patent Document 4] Japanese Patent Application Publication No. 09-109330 [Patent Document 5] Japanese Patent Application Laid-Open No. 2009-004568 [Patent Document 6] Japanese Patent Application Publication No. 2022-133959 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a multilayer film suitable as a film substrate for semiconductor manufacturing processes, which can replace films of soft polyvinyl chloride resin compositions and thereby fundamentally solves the problems caused by plasticizers, and a semiconductor manufacturing process film using the multilayer film as a film substrate. [Means for solving the problem]

[0006] As a result of extensive research, the present inventors have found that the above object can be achieved by a specific multilayer film.

[0007] That is, the various aspects of the present invention are as follows. [1]. A multilayer film for use as a film substrate for semiconductor process films, comprising an (α1) first polyolefin layer, a (β) elastomer layer, and an (α2) second polyolefin layer laminated directly in this order, wherein the (α1) first polyolefin layer is made of polyethylene or polypropylene, the (β) elastomer layer is made of a hydrogenated product of a block copolymer of an aromatic vinyl compound and a conjugated diene compound, and the (α2) second polyolefin layer is made of polyethylene or polypropylene. [2]. The first polyolefin layer (α1) has a density of 910 to 940 kg / m 3 and the (α2) second polyolefin layer is made of polyethylene having a density of 910 to 940 kg / m 3 The multilayer film for film substrate of semiconductor process film according to [1], which consists of polyethylene. [3]. The multilayer film for use as a film substrate for semiconductor manufacturing processes according to item [1], wherein the first polyolefin layer (α1) is made of polypropylene, and the second polyolefin layer (α2) is made of polypropylene. [4]. A multilayer film for a film substrate of a semiconductor processing film according to item [1], wherein the thickness of the first polyolefin layer (α1) is 1 μm or more, the thickness of the elastomer layer (β) is 70% or more of the total thickness of the multilayer film, and the thickness of the second polyolefin layer (α2) is 1 μm or more. [5]. The multilayer film for use as a film substrate for semiconductor manufacturing processes according to item [4], wherein the multilayer film has a total thickness of 50 to 300 μm. [6]. A film for semiconductor manufacturing processes, comprising the multilayer film for film substrate of a film for semiconductor manufacturing processes according to any one of items [1] to [5]. [7]. [2] A method for producing a multilayer film for use as a film substrate for semiconductor manufacturing processes, comprising the step of irradiating the multilayer film with an electron beam. [Effects of the Invention]

[0008] The multilayer film of the present invention fundamentally solves the problems caused by plasticizers in films of flexible polyvinyl chloride resin compositions by not incorporating plasticizers, and has good expandability. A preferred multilayer film of the present invention also has good flexibility, blocking resistance, and heat resistance, and exhibits a good balance between flexibility and expandability and blocking resistance and heat resistance. Therefore, the multilayer film of the present invention can be suitably used as a film substrate for semiconductor manufacturing processes, such as dicing films, backgrinding films, and die attach films. DETAILED DESCRIPTION OF THE INVENTION

[0009] In this specification, the term "resin" is used to include a resin mixture containing two or more resins and a resin composition containing components other than resin. The same applies to the term "elastomer."

[0010] In this specification, the term "film" is used interchangeably or interchangeably with "sheet." In this specification, the terms "film" and "sheet" are used to refer to materials that can be industrially wound into rolls. The term "plate" is used to refer to materials that cannot be industrially wound into rolls. In addition, in this specification, laminating one layer and another layer in order includes both directly laminating the layers and laminating the layers with one or more additional layers, such as an anchor coat, interposed between them.

[0011] In this specification, the term "more than or equal to" in relation to a numerical range means a certain number or more than a certain number. For example, 20% or more means 20% or more than 20%. The term "less than or equal to" in relation to a numerical range means a certain number or less than a certain number. For example, 20% or less means 20% or less than 20%. Furthermore, the symbol "to" in relation to a numerical range means a certain number, more than a certain number and less than another certain number, or another certain number. Here, another certain number is a number greater than the certain number. For example, 10 to 90% means 10%, more than 10% and less than 90%, or 90%. Furthermore, the upper and lower limits of a numerical range can be arbitrarily combined, and embodiments incorporating such combinations can be interpreted. For example, from a statement regarding the numerical range of a certain characteristic such as "usually 10% or more, preferably 20% or more. On the other hand, it is usually 40% or less, preferably 30% or less," or "usually 10 to 40%, preferably 20 to 30%," it can be read that the numerical range of the certain characteristic is 10 to 40%, 20 to 30%, 10 to 30%, or 20 to 40% in one embodiment.

[0012] Other than in the examples, or where otherwise specified, all numerical values ​​used in the specification and claims should be understood to be modified by the term "about." Without attempting to limit the application of the doctrine of equivalents to the claims, each numerical value should be construed in light of the number of significant digits and by applying ordinary rounding techniques.

[0013] In this specification, terms specifying shapes or geometric conditions, such as parallel, orthogonal, and perpendicular, are intended to include not only the strict meanings but also substantially the same states.

[0014] In this specification, when it is explained that "comprises a certain substance," it is to be understood that, in one embodiment, it contains a certain substance, consists of a certain substance, or consists only of a certain substance. For example, from the explanation that "composition A comprises substances a1 and a2," it is to be understood that, in one embodiment, composition A comprises substances a1 and a2, composition A consists of substances a1 and a2, or composition A consists only of substances a1 and a2.

[0015] 1. Multilayer film: The multilayer film of the present invention comprises (α1) a first polyolefin layer, (β) an elastomer layer, and (α2) a second polyolefin layer laminated directly in this order.

[0016] The (α1) first polyolefin layer and the (α2) second polyolefin layer (hereinafter sometimes simply referred to as "(α) polyolefin layer") are made of (A) polyolefin. The (α) polyolefin layer functions to suppress problems during film formation of the multilayer film of the present invention and to impart sufficient blocking resistance, heat resistance, and solvent resistance to the multilayer film of the present invention. The component (A) polyolefin constituting the (α1) first polyolefin layer and the component (A) polyolefin constituting the (α2) second polyolefin layer may be the same polyolefin or different polyolefins.

[0017] The (β) elastomer layer is made of (B) a hydrogenated product of a block copolymer of an aromatic vinyl compound and a conjugated diene compound, and serves to impart sufficient flexibility and expandability to the multilayer film of the present invention.

[0018] The thickness of the multilayer film of the present invention is not particularly limited and can be appropriately selected taking into consideration the specific type of film to be used in semiconductor manufacturing processes and its intended use. The thickness of the multilayer film of the present invention may be usually 30 to 500 μm, preferably 50 to 300 μm, more preferably 60 to 200 μm, even more preferably 70 to 150 μm, and most preferably 80 to 120 μm.

[0019] The thickness of the (α1) first polyolefin layer can be appropriately selected from the viewpoints of blocking resistance, heat resistance, and solvent resistance, taking into account the specific type of the intended semiconductor manufacturing process film and its usage mode. From the viewpoints of blocking resistance, heat resistance, and solvent resistance, the thickness of the (α1) first polyolefin layer may be usually 1 μm or more, preferably 2 μm or more, and more preferably 3 μm or more. On the other hand, from the viewpoints of flexibility and expandability, the thickness may be usually 15% or less, preferably 12% or less, more preferably 10% or less, and even more preferably 8% or less of the thickness of the multilayer film of the present invention.

[0020] The thickness of the second polyolefin layer (α2) can be appropriately selected from the viewpoints of blocking resistance, heat resistance, and solvent resistance, taking into account the specific type of the intended semiconductor manufacturing process film and its usage mode. From the viewpoints of blocking resistance, heat resistance, and solvent resistance, the thickness of the second polyolefin layer (α2) may be usually 1 μm or more, preferably 2 μm or more, and more preferably 3 μm or more. On the other hand, from the viewpoints of flexibility and expandability, the thickness may be usually 15% or less, preferably 12% or less, more preferably 10% or less, and even more preferably 8% or less of the thickness of the multilayer film of the present invention.

[0021] The thickness of the (β) elastomer layer can be appropriately selected from the viewpoints of flexibility and expandability, taking into account the specific type of the intended semiconductor manufacturing process film and its usage mode. From the viewpoints of flexibility and expandability, the thickness of the (β) elastomer layer may be typically 70% or more, preferably 76% or more, more preferably 80% or more, and even more preferably 84% or more of the thickness of the multilayer film of the present invention. On the other hand, from the viewpoints of blocking resistance, heat resistance, and solvent resistance, the thickness may be typically 98% or less, preferably 96% or less, and more preferably 94% or less of the thickness of the multilayer film of the present invention.

[0022] The components constituting each layer of the multilayer film of the present invention will be described below.

[0023] (A) Polyolefin: The polyolefin component (A) constitutes the first polyolefin layer (α1) and the second polyolefin layer (α2) of the multilayer film of the present invention. The polyolefin component (A) is a polymer primarily containing structural units derived from α-olefins. Here, "primarily containing structural units derived from α-olefins" means that the content of structural units derived from α-olefins is 60 to 100 mol%. Examples of the α-olefins include ethylene, propylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-pentene-1.

[0024] Examples of the polyolefin component (A) include ethylene-based resins, propylene-based resins, and 4-methyl-1-pentene-based resins.

[0025] The ethylene-based resin is a polymer primarily containing structural units derived from ethylene. Here, "primarily containing structural units derived from ethylene" means that the content of structural units derived from ethylene is 60 to 100 mol %. Examples of the ethylene-based resin include polyethylene, ethylene-vinyl acetate copolymer, ethylene-unsaturated carboxylic acid ester copolymer, ethylene-unsaturated carboxylic acid copolymer, ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer, and ionomer.

[0026] Examples of the polyethylene include very low density polyethylene, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, and ethylene-α-olefin copolymers such as ethylene-1-butene copolymer, ethylene-1-hexene copolymer, and ethylene-1-octene copolymer.

[0027] Examples of the ethylene-unsaturated carboxylic acid ester copolymer include ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-butyl acrylate copolymer, and other ethylene-(meth)acrylic acid alkyl ester copolymers, where (meth)acrylic acid refers to acrylic acid or methacrylic acid.

[0028] Examples of the ethylene-unsaturated carboxylic acid copolymer include an ethylene-acrylic acid copolymer and an ethylene-methacrylic acid copolymer.

[0029] Examples of the ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer include ethylene-methacrylic acid-methacrylic acid alkyl ester copolymers such as ethylene-methacrylic acid-ethyl methacrylate copolymer, ethylene-methacrylic acid-acrylic acid alkyl ester copolymers such as ethylene-methacrylic acid-butyl acrylate copolymer, ethylene-acrylic acid-methacrylic acid alkyl ester copolymers such as ethylene-acrylic acid-ethyl methacrylate copolymer, and ethylene-acrylic acid-acrylic acid alkyl ester copolymers such as ethylene-acrylic acid-butyl acrylate copolymer.

[0030] The ionomer is a polymer in which some or all of the carboxyl groups of the ethylene-unsaturated carboxylic acid copolymer or the ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer have been neutralized with metal ions, such as lithium ions, sodium ions, potassium ions, rubidium ions, cesium ions, zinc ions, magnesium ions, and manganese ions.

[0031] The propylene-based resin is a polymer mainly containing structural units derived from propylene. Here, "mainly containing structural units derived from propylene" means that the content of structural units derived from propylene is 60 to 100 mol%. Examples of the propylene-based resin include polypropylenes such as propylene homopolymers and copolymers (including block copolymers and random copolymers) of propylene with one or more α-olefins (e.g., ethylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene).

[0032] The 4-methyl-1-pentene resin is a polymer mainly containing structural units derived from 4-methyl-1-pentene. Here, "mainly containing structural units derived from 4-methyl-1-pentene" means that the content of structural units derived from 4-methyl-1-pentene is 60 to 100 mol%. Examples of the 4-methyl-1-pentene resin include poly(4-methyl-1-pentene), such as a 4-methyl-1-pentene homopolymer and a copolymer (including a block copolymer and a random copolymer) of 4-methyl-1-pentene with one or more α-olefins (e.g., ethylene, propylene, 1-butene, 1-hexene, and 1-octene).

[0033] Among these, polyethylene, polypropylene, and poly(4-methyl-1-pentene) are preferred as the component (A) polyolefin from the viewpoints of blocking resistance, heat resistance, and solvent resistance, and polyethylene and polypropylene are more preferred from the viewpoint of interlayer strength between the (α) polyolefin layer and the (β) elastomer layer.

[0034] The polyethylene that can be used as the polyolefin component (A) (hereinafter, sometimes referred to as "polyethylene (A1)") will be described below.

[0035] The density of the polyethylene component (A1), measured by the underwater displacement method in accordance with JIS K7112:1999, is preferably 905 kg / m from the viewpoints of blocking resistance, heat resistance, and solvent resistance. 3 More preferably, 910 kg / m 3 More preferably, 915 kg / m 3 On the other hand, the density of the polyethylene component (A1) is preferably 960 kg / m or more from the viewpoints of expandability, flexibility, and transparency. 3 Less than 950 kg / m 3 or less, more preferably 940 kg / m 3 or less, even more preferably 930 kg / m 3 It may be the following:

[0036] From the viewpoints of blocking resistance, heat resistance, and solvent resistance, the fusion enthalpy of the polyethylene component (A1) may be preferably 80 J / g or more, more preferably 90 J / g or more, even more preferably 95 J / g or more, and still more preferably 100 J / g or more. On the other hand, from the viewpoints of expandability, flexibility, and transparency, the fusion enthalpy of the polyethylene component (A1) may be preferably 220 J / g or less, more preferably 200 J / g or less, even more preferably 180 J / g or less, and still more preferably 160 J / g or less.

[0037] From the viewpoints of blocking resistance, heat resistance, and solvent resistance, the melting point of the polyethylene component (A1) may be preferably 95° C. or higher, more preferably 100° C. or higher, and even more preferably 105° C. or higher. From the viewpoints of blocking resistance, heat resistance, and solvent resistance, the melting point of the polyethylene component (A1) is preferably higher.

[0038] In this specification, the melting point and melting enthalpy of the polyethylene component (A1) are calculated from the DSC second melting curve (the melting curve measured during the final heating process) measured using a differential scanning calorimeter (DSC) in accordance with JIS K7121-1987, using a program that involves holding at 190°C for 5 minutes, cooling to -50°C at 10°C / min, holding at -50°C for 5 minutes, and then heating to 190°C at 10°C / min. The melting point is the peak-top temperature of the melting peak that appears in the second melting curve. When two or more melting peaks are observed, the melting point is the peak-top temperature of the melting peak with the greatest peak top height. Figure 1 shows a measurement example of the polyethylene component (A1-1) used in the examples. The lower curve in Figure 1 is the DSC second melting curve, and the upper curve is the DSC crystallization curve. It should be noted that the melting peak appearing in a DSC second melting curve of polyethylene usually has a long, gradual base on the low-temperature side; and that the baseline should be drawn so that the line extending from the high-temperature side baseline to the low-temperature side, as shown in Figure 1 of JIS K7121-1987, Section 9. How to read DTA or DSC curves, coincides with the line extending from the same low-temperature side baseline to the high-temperature side.

[0039] The melt mass flow rate of the polyethylene component (A1), measured in accordance with JIS K7210-1:2014 under conditions of 190°C and 21.18N, may be preferably 0.1 to 50 g / 10 min, more preferably 0.5 to 30 g / 10 min, and even more preferably 1 to 20 g / 10 min, from the viewpoint of film formability.

[0040] The polyethylene component (A1) can be one of these or a mixture of two or more of them. When a mixture of two or more polyethylene components (A1) is used, it goes without saying that the mixture must satisfy the above-mentioned properties.

[0041] The polypropylene (hereinafter sometimes referred to as "(A2) polypropylene") that can be used as the above-mentioned component (A) polyolefin will be explained. From the viewpoints of blocking resistance, heat resistance, and solvent resistance, the melting enthalpy of the above-mentioned component (A2) polypropylene may be preferably 50 J / g or more, more preferably 60 J / g or more, even more preferably 70 J / g or more, and even more preferably 80 J / g or more. On the other hand, from the viewpoints of expandability and flexibility, the melting enthalpy of the above-mentioned component (A2) polypropylene may be preferably 120 J / g or less, more preferably 115 J / g or less, and even more preferably 110 J / g or less.

[0042] From the viewpoints of blocking resistance, heat resistance, and solvent resistance, the melting point of the polypropylene component (A2) is preferably 120°C or higher, more preferably 130°C or higher, even more preferably 140°C or higher, still more preferably 150°C or higher, and most preferably 160°C or higher. From the viewpoints of blocking resistance, heat resistance, and solvent resistance, the melting point of the polypropylene component (A2) is preferably higher. Furthermore, from the viewpoints of blocking resistance, heat resistance, and solvent resistance, the polypropylene component (A2) is preferably one that does not exhibit a sub-peak with a peak top temperature of less than 120°C in the DSC second melting curve described below.

[0043] In this specification, the melting point and melting enthalpy of the above-mentioned component (A2) polypropylene are calculated from the DSC second melting curve (the melting curve measured during the final heating process) measured using a differential scanning calorimeter (DSC) in accordance with JIS K7121-1987, using a program that involves holding at 230°C for 5 minutes, cooling to -50°C at 10°C / min, holding at -50°C for 5 minutes, and then heating to 230°C at 10°C / min. The melting point is the peak-top temperature of the melting peak that appears in the second melting curve. When two or more melting peaks are observed, the peak-top temperature of the melting peak with the greatest peak top height is taken as the melting point. Figure 1 shows an example of measurement of the following component (A2-1), propylene homopolymer, used in the examples. The lower curve in Figure 1 is the DSC second melting curve, and the upper curve is the DSC crystallization curve. It should be noted that the melting peak appearing in the DSC second melting curve of polypropylene usually has a long, gradual base on the low-temperature side; and that the baseline should be drawn so that the line extending from the high-temperature side baseline to the low-temperature side in Figure 1 of JIS K7121-1987, Section 9. How to read DTA or DSC curves, coincides with the line extending from the same low-temperature side baseline to the high-temperature side.

[0044] The melt mass flow rate of the polypropylene component (A2), measured in accordance with JIS K7210-1:2014 under conditions of 230°C and 21.18N, may be preferably 0.1 to 50 g / 10 min, more preferably 1 to 40 g / 10 min, and even more preferably 3 to 30 g / 10 min, from the viewpoint of film formability.

[0045] Examples of polypropylenes having the above-described properties that can be used as the component (A2) polypropylene include isotactic polypropylenes such as propylene homopolymers and copolymers (including block copolymers and random copolymers) of propylene with small amounts of one or more of other α-olefins (e.g., ethylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene).

[0046] The mesodiad fraction of the isotactic polypropylene (the proportion of structural units derived from two consecutive propylene units that have an isotactic structure) may be usually 90 mol% or more, more preferably 95 mol% or more, and typically 97 to 100 mol%.

[0047] From the viewpoint of transparency, the polypropylene component (A2) may preferably contain one or more selected from the group consisting of propylene homopolymers and random copolymers of propylene and small amounts of other α-olefins, and more preferably may consist of one or more selected from the group consisting of propylene homopolymers and random copolymers of propylene and small amounts of other α-olefins.

[0048] When the isotactic polypropylene is a random copolymer of the propylene and a small amount of one or more other α-olefins, the content of structural units derived from the α-olefins may be, depending on the mesodiad fraction and the amount of abnormal insertion, preferably 10 mol % or less, more preferably 8 mol % or less, even more preferably 6 mol % or less, still more preferably 4 mol % or less, and most preferably 2 mol % or less, from the viewpoints of suppressing trouble during film formation, blocking resistance, heat resistance, and solvent resistance.

[0049] The polypropylene component (A2) can be one of these or a mixture of two or more of them. When a mixture of two or more polypropylene components (A2) is used, it goes without saying that the mixture must satisfy the above-mentioned properties.

[0050] The polyolefin component (A) may contain, as desired, additives commonly used in polyolefins, provided that the purpose of the present invention is not adversely affected. Examples of such additives include antioxidants, neutralizing agents, slip agents, antiblocking agents, antifogging agents, antioxidants, weather resistance stabilizers, light resistance stabilizers, antistatic agents such as glycerin fatty acid esters, nucleating agents, inorganic colorants, organic colorants, and masterbatches for dry blending of these additives.

[0051] Examples of the antioxidant include hindered phenol-based antioxidants, phosphite-based antioxidants, and thioether-based antioxidants.

[0052] Examples of the neutralizing agent include fatty acid metal salts such as calcium stearate, zinc stearate, and magnesium stearate, hydrotalcites, and composite metal hydroxides such as lithium aluminum composite hydroxide.

[0053] Examples of the slip agent include fatty acid amides such as erucic acid amide, oleic acid amide, stearic acid amide, behenic acid amide, ethylene bisstearic acid amide, ethylene bisoleic acid amide, stearyl erucamide, and oleyl palmitamide.

[0054] Examples of the anti-blocking agent include inorganic fine particles such as silica, and organic fine particles such as cross-linked acrylic resin.

[0055] As the additive, one or more of these can be used.

[0056] The amount of the additives is not particularly limited as long as it does not detract from the object of the present invention, since they are optional components. In one embodiment, the amount of the additives may be 5 parts by mass or less, 4 parts by mass or less, 3 parts by mass or less, 2 parts by mass or less, 1 part by mass or less, 0.5 parts by mass or less, 0 to 0.5 parts by mass, or about 0.01 to 5 parts by mass, per 100 parts by mass of the polyolefin component (A).

[0057] In one embodiment, the component (A) polyolefin may be free of any one or more of the additives listed above.

[0058] As used herein, "not containing a certain component" means that the component is not intentionally blended. In the technical field of resin compositions, when a component is intentionally blended, it is usually blended in an amount of 0.01 part by mass or more. Therefore, "not containing a certain component" can also be rephrased as meaning that the content of the component is usually less than 0.01 part by mass, preferably 0.001 part by mass or less, and more preferably 0 to 0.0001 part by mass, per 100 parts by mass of the polyolefin component (A).

[0059] The component (A) polyolefin constituting the (α1) first polyolefin layer and the component (A) polyolefin constituting the (α2) second polyolefin layer may be the same or different. The type and amount of additive contained in the component (A) polyolefin constituting the (α1) first polyolefin layer and the type and amount of additive contained in the component (A) polyolefin constituting the (α2) second polyolefin layer may be the same or different.

[0060] (B) Hydrogenated block copolymer of aromatic vinyl compound and conjugated diene compound: The component (B), a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, constitutes the elastomer layer (β).

[0061] The hydrogenated product of the block copolymer of the aromatic vinyl compound and the conjugated diene compound (B) is a substance obtained by adding hydrogen to a block polymer containing one or more aromatic vinyl compound polymer segments (b1) and one or more conjugated diene compound polymer segments (b2), thereby converting some or all of the carbon-carbon double bonds of the block polymer into carbon-carbon single bonds. Examples of the hydrogenated product of the block copolymer of the aromatic vinyl compound and the conjugated diene compound (B) include those having segment structures such as (b1)-(b2), (b1)-(b2)-(b1), (b2)-(b1)-(b2), (b1)-(b2)-(b1)-(b2), and (b1)-(b2)-(b1)-(b2)-(b1).

[0062] The aromatic vinyl compound is a polymerizable monomer having a polymerizable carbon-carbon double bond and an aromatic ring. Examples of the aromatic vinyl compound include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N,N-diethyl-p-aminoethylstyrene, vinyltoluene, and p-tert-butylstyrene. The aromatic vinyl compound may preferably contain styrene. One or more of these compounds may be used as the aromatic vinyl compound.

[0063] The conjugated diene compound is a polymerizable monomer having a structure in which two carbon-carbon double bonds are bonded by one carbon-carbon single bond. Examples of the conjugated diene compound include 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3-octadiene, 1,3-cyclohexadiene, 2-methyl-1,3-octadiene, 1,3,7-octatriene, 7-methyl-3-methyleneocta-1,6-diene (β-myrcene), 3,7,11-trimethyl-1,3,6,10-dodecatetraene (α-farnesene), 7,11-dimethyl-3-methylene-1,6,10-dodecatriene (β-farnesene), and chloroprene (2-chloro-1,3-butadiene). The conjugated diene compound may preferably contain one or more selected from the group consisting of 1,3-butadiene, isoprene, β-myrcene, α-farnesene, and β-farnesene, and one or more of these can be used as the conjugated diene compound.

[0064] The (b1) aromatic vinyl compound polymer segment is a polymer segment mainly containing structural units derived from the aromatic vinyl compound. Here, "mainly containing" means that the content of structural units derived from the aromatic vinyl compound is 60 to 100% by mass. From the viewpoint of heat resistance, the content of structural units derived from the aromatic vinyl compound may be preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, still more preferably 95% by mass or more, and most preferably 99 to 100% by mass.

[0065] Examples of the (b1) aromatic vinyl compound polymer segment include one or more polymer segments of the above aromatic vinyl compounds, and copolymer segments of the above aromatic vinyl compounds and the above conjugated diene compounds. When there are two or more (b1) aromatic vinyl compound polymer segments, they may have the same structure or different structures.

[0066] The (b2) conjugated diene compound polymer segment is a polymer segment mainly containing structural units derived from the conjugated diene compound. Here, "mainly containing" means that the content of structural units derived from the conjugated diene compound is 60 to 100% by mass. From the viewpoints of flexibility and expandability, the content of structural units derived from the conjugated diene compound may be preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, still more preferably 95% by mass or more, and most preferably 99 to 100% by mass.

[0067] Examples of the (b2) conjugated diene compound polymer segment include one or more polymer segments of the conjugated diene compound, and a copolymer segment of the conjugated diene compound and the aromatic vinyl compound. When there are two or more (b2) conjugated diene compound polymer segments, they may have the same structure or different structures.

[0068] The hydrogenation rate of the hydrogenated product of the block copolymer of the aromatic vinyl compound and the conjugated diene compound (component (B)) (the ratio of the number of carbon-carbon single bonds resulting from hydrogenation to the number of carbon-carbon double bonds in the block copolymer of the aromatic vinyl compound and the conjugated diene compound before hydrogenation) may be, from the viewpoint of heat resistance, usually 50 mol % or more, preferably 60 mol % or more, more preferably 70 mol % or more, even more preferably 80 mol % or more, and most preferably 90 to 100 mol %.

[0069] The content of structural units derived from the aromatic vinyl compound in the hydrogenated block copolymer of component (B) an aromatic vinyl compound and a conjugated diene compound may be preferably 55% by mass or less, more preferably 45% by mass or less, even more preferably 35% by mass or less, and even more preferably 25% by mass or less, from the viewpoints of flexibility and expandability. On the other hand, the content of structural units derived from the aromatic vinyl compound in component (B) may be preferably 3% by mass or more, more preferably 6% by mass or more, and even more preferably 9% by mass or more, from the viewpoints of heat resistance and suppressing the generation of whiskers when the semiconductor process film is mechanically cut.

[0070] The melt mass flow rate of the hydrogenated block copolymer of component (B), an aromatic vinyl compound and a conjugated diene compound, measured in accordance with JIS K7210-1:2014 at 190°C and 21.18N may be preferably 0.01 to 50 g / 10 min, more preferably 0.1 to 30 g / min, from the viewpoint of film formability.

[0071] The melt mass flow rate of the hydrogenated block copolymer of component (B), an aromatic vinyl compound and a conjugated diene compound, measured in accordance with JIS K7210-1:2014 at 230°C and 21.18N may be preferably 0.1 to 100 g / 10 min, more preferably 0.3 to 50 g / min, from the viewpoint of film formability.

[0072] Examples of component (B), hydrogenated block copolymers of aromatic vinyl compounds and conjugated diene compounds, include styrene-ethylene-butene block copolymer (SEB), styrene-ethylene-propylene block copolymer (SEP), styrene-ethylene-butene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-butadiene-butylene-styrene copolymer (partially hydrogenated styrene-butadiene-styrene copolymer: SBBS), partially hydrogenated styrene-isoprene-styrene copolymer, partially hydrogenated styrene-isoprene-butadiene-styrene copolymer, and hydrogenated styrene-β-farnesene block copolymer.

[0073] In one embodiment, the component (B), a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, may comprise a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound having a structural unit derived from β-farnesene, such as the hydrogenated styrene-β-farnesene block copolymer. β-Farnesene is obtained by fermenting sugars from sugarcane, which reduces the environmental impact.

[0074] As the component (B), the hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, one or a mixture of two or more of these compounds can be used. When a mixture of two or more compounds is used as the component (B), the hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, it goes without saying that the mixture should satisfy the above-mentioned properties.

[0075] The hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound (component (B)) may contain additives commonly used in so-called styrene elastomers, as desired, to the extent that the object of the present invention is not adversely affected. Examples of such additives include antioxidants, neutralizing agents, slip agents, antiblocking agents, antifogging agents, antioxidants, weather resistance stabilizers, light resistance stabilizers, antistatic agents such as glycerin fatty acid esters, inorganic colorants, organic colorants, and masterbatches for dry blending of these additives.

[0076] Examples of the antioxidant include hindered phenol-based antioxidants, phosphite-based antioxidants, and thioether-based antioxidants.

[0077] Examples of the neutralizing agent include fatty acid metal salts such as calcium stearate, zinc stearate, and magnesium stearate, hydrotalcites, and composite metal hydroxides such as lithium aluminum composite hydroxide.

[0078] Examples of the slip agent include fatty acid amides such as erucic acid amide, oleic acid amide, stearic acid amide, behenic acid amide, ethylene bisstearic acid amide, ethylene bisoleic acid amide, stearyl erucamide, and oleyl palmitamide.

[0079] Examples of the anti-blocking agent include inorganic fine particles such as silica and talc, and organic fine particles such as cross-linked acrylic resin.

[0080] As the additive, one or more of these can be used.

[0081] The amount of the additives is not particularly limited as long as it does not detract from the object of the present invention, since they are optional components. In one embodiment, the amount of the additives may be 5 parts by mass or less, 4 parts by mass or less, 3 parts by mass or less, 2 parts by mass or less, 1 part by mass or less, 0.5 parts by mass or less, 0 to 0.5 parts by mass, or about 0.01 to 5 parts by mass, relative to 100 parts by mass of the hydrogenated block copolymer of component (B) an aromatic vinyl compound and a conjugated diene compound.

[0082] In one embodiment, the component (B), a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, may not contain any one or more of the above additives.

[0083] As used herein, "not containing a certain component" means that the component is not intentionally blended. In the technical field of resin compositions, when a component is intentionally blended, it is typically blended in an amount of 0.01 part by mass or more. Therefore, "not containing a certain component" can also be rephrased as meaning that the content of the component is typically less than 0.01 part by mass, preferably 0.001 part by mass or less, and more preferably 0 to 0.0001 part by mass, per 100 parts by mass of the hydrogenated block copolymer of component (B) of an aromatic vinyl compound and a conjugated diene compound.

[0084] 2. Film forming method: The method for producing the multilayer film of the present invention is not particularly limited, and any known multilayer film production method can be appropriately selected. A preferred method for producing the multilayer film of the present invention is, for example, to use a film production apparatus equipped with a plurality of extruders, a coextrusion T-die, a first chill roll, and a take-up device having a mechanism for pressing a molten film against the first chill roll, (1) continuously co-extruding a molten multilayer film from the co-extrusion T-die; (2) a step of pressing the molten multilayer film extruded in the step (1) against and enveloping the rotating first chill roll by the pressing mechanism; and (3) A step of delivering the multilayer film held by the first chill roll in the step (2) from the first chill roll to the next rotating roll.

[0085] The extruder is not particularly limited and may be appropriately selected from known extruders, such as a single-screw extruder, a co-rotating twin-screw extruder, and a counter-rotating twin-screw extruder.

[0086] To prevent deterioration of the raw material resin, it is preferable to purge the inside of the extruder with nitrogen. It is also preferable to dry the raw material resin before using it for film formation. It is also preferable to transport the dried resin directly from the dryer to the extruder and charge it.

[0087] The coextrusion T-die is not particularly limited, and any known coextrusion T-die can be appropriately selected and used. Examples of the coextrusion T-die include multi-manifold type, stack plate type, and feed block type.

[0088] The first chill roll is not particularly limited, and any known rotating roll having a cooling mechanism can be appropriately selected and used. Examples of the first chill roll include a mirror-finished or matte metal rotating roll having a mechanism for circulating a cooling medium such as water or oil inside the roll.

[0089] The pressing mechanism is not particularly limited, and any known pressing mechanism can be appropriately selected and used. Examples of the pressing mechanism include an air knife, an air chamber, a vacuum chamber, a nip roll, and combinations thereof.

[0090] The set temperature of the co-extrusion T-die outlet (lip) in step (1) can be appropriately selected from the viewpoints of stably performing the step of continuously co-extruding the molten multilayer film and suppressing deterioration of the raw material resins. From the viewpoint of stably performing the step of continuously co-extruding the molten multilayer film, the set temperature may be usually 200°C or higher, preferably 220°C or higher, and more preferably 230°C or higher. On the other hand, from the viewpoint of suppressing deterioration of the raw material resins, the set temperature may be usually 300°C or lower, preferably 280°C or lower, and more preferably 260°C or lower.

[0091] The surface temperature of the first chill roll can be appropriately selected from the viewpoints of completely cooling and solidifying the multilayer film when it is delivered from the first chill roll to the next rotating roll in step (3) and preventing condensation from forming on the surface of the first chill roll. From the viewpoint of completely cooling and solidifying the multilayer film when it is delivered from the first chill roll to the next rotating roll in step (3), the surface temperature of the first chill roll may be typically 80°C or lower, preferably 70°C or lower, more preferably 60°C or lower, and even more preferably 50°C or lower. On the other hand, from the viewpoint of preventing condensation from forming on the surface of the first chill roll, the surface temperature may be typically 15°C or higher, preferably 20°C or higher, more preferably 25°C or higher, and even more preferably 30°C or higher, depending on the temperature and humidity of the film-forming environment.

[0092] When a nip roll is used as the pressing mechanism, it is preferable to use one having a mechanism for controlling the surface temperature of the nip roll. In this case, the surface temperature of the nip roll can be appropriately selected taking into consideration the surface material of the nip roll from the viewpoint of suppressing or preventing the problem of the molten multilayer film adhering to the nip roll and from the viewpoint of preventing condensation on the surface of the nip roll. From the viewpoint of suppressing or preventing the problem of the molten multilayer film adhering to the nip roll, the surface temperature of the nip roll may be usually 80°C or lower, preferably 70°C or lower, more preferably 60°C or lower, and even more preferably 50°C or lower, although it depends on the surface material of the nip roll. On the other hand, from the viewpoint of preventing condensation on the surface of the nip roll, it may be usually 15°C or higher, preferably 20°C or higher, more preferably 25°C or higher, and even more preferably 30°C or higher, although it depends on the temperature and humidity of the film production environment.

[0093] The step (3) is a step of sending the multilayer film, which has been pressed against and embraced by the first chill roll in the step (2), to the next rotating roll. By pressing the molten multilayer film against and embraced by the first chill roll, it is possible to ensure that the multilayer film is completely cooled and solidified when sent to the next rotating roll.

[0094] Figure 3 is a conceptual diagram of the film-forming apparatus used in the examples. The film-forming apparatus is equipped with a two-kind, three-layer multi-manifold co-extrusion T-die 1, extruders 2 for both outer layers, an extruder 3 for an intermediate layer, and a winding device having a nipping mechanism with a first chill roll (mirror-finish metal roll) 5 and a nip roll (matt-finish silicone rubber roll) 6. (1) The raw resins for the outer layers are continuously extruded by extruder 2, and the raw resin for the middle layer is continuously extruded by extruder 3 from a coextrusion T-die 1 as a two-kind, three-layer molten multilayer film 4. (2) The molten multilayer film 4 extruded in the above step (1) is nipped by nip rolls 6 and pressed against and embraced by the rotating first chill roll 5. (3) The multilayer film 4 held by the first chill roll 5 in the above step (2) is sent from the first chill roll 5 to the next rotating roll 7, where a multilayer film 8 is formed.

[0095] In the multilayer film of the present invention, when both the resin constituting the first polyolefin layer (α1) and the second polyolefin layer (α2) are the ethylene-based resin, the production method thereof may, in one embodiment, further include a step of irradiating the multilayer film with an electron beam after obtaining the multilayer film by a known multilayer film production method. Both the ethylene-based resin and the component (B), a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, are crosslinked by electron beam irradiation, which can suppress the generation of so-called whiskers when the film is mechanically cut in the semiconductor manufacturing process and can improve heat resistance.

[0096] The dose of electron beam irradiation is appropriately selected from the viewpoint of obtaining the desired effect, taking into consideration the type of constituent resin of each layer forming the multilayer film, and the thickness of each layer and the entire film. The dose of electron beam irradiation may be preferably 10 to 300 KGy, more preferably 20 to 200 KGy, and even more preferably 30 to 100 KGy.

[0097] It is preferable to irradiate the multilayer film with electron beams while cooling it by holding it against a cooling roll or the like, as this can prevent the multilayer film from generating heat due to electron beam irradiation and causing production problems.

[0098] 3. Semiconductor manufacturing process film: The semiconductor manufacturing process film of the present invention includes the multilayer film of the present invention. The semiconductor manufacturing process film of the present invention is usually produced by using the multilayer film of the present invention as a film substrate, forming a pressure-sensitive adhesive layer on one side of the film substrate directly or via an anchor coat, and then slitting the film to a desired width.

[0099] Examples of adhesives for forming the adhesive layer include acrylic adhesives such as poly(meth)acrylic acid alkyl esters and copolymers of (meth)acrylic acid alkyl esters with other monomers copolymerizable with (meth)acrylic acid alkyl esters, such as (meth)acrylic acid; rubber adhesives such as natural rubber and butyl-isoprene rubber; polyurethane adhesives; polyester adhesives; polystyrene adhesives; and silicone adhesives.

[0100] In one preferred embodiment, the adhesive may be one that can be cured by heat treatment or active energy ray irradiation to reduce its adhesive strength. By reducing the adhesive strength, the semiconductor manufacturing process film can be easily peeled cleanly from the workpiece without leaving any adhesive residue. Furthermore, the amount of static electricity generated when peeling the semiconductor manufacturing process film from the workpiece can be reduced. Examples of adhesives that can reduce their adhesive strength include adhesives having two or more reactive functional groups per molecule (e.g., amino groups, vinyl groups, epoxy groups, methacryloxy groups, acryloxy groups, isocyanate groups, etc.), and adhesive compositions containing such adhesives and at least one of an isocyanate-based curing agent, a photopolymerization initiator, and an organic peroxide.

[0101] In one preferred embodiment, the pressure-sensitive adhesive may have excellent transparency, which is required for films used in semiconductor manufacturing processes, for example, from the viewpoint of ensuring sufficient visibility during laser marking. Here, "a pressure-sensitive adhesive with excellent transparency" refers to a pressure-sensitive adhesive having a visible light transmittance of typically 50% or more, preferably 70% or more, more preferably 80% or more, and even more preferably 85% or more. Here, the visible light transmittance can be calculated as the ratio of the integrated area of ​​the transmission spectrum of the pressure-sensitive adhesive at wavelengths of 380 to 780 nanometers, measured using a Shimadzu Corporation spectrophotometer "Solid Spec-3700" (trade name) and a quartz cell with an optical path length of 10 mm, to the integrated area of ​​the transmission spectrum assuming a transmittance of 100% over the entire wavelength range of 380 to 780 nanometers.

[0102] In one preferred embodiment, the pressure-sensitive adhesive may be an antistatic pressure-sensitive adhesive. The surface resistivity of the pressure-sensitive adhesive layer formed using the antistatic pressure-sensitive adhesive is typically 1×10 6 ~1×10 11 Ω / □, preferably 1×10 7 ~1×10 10 Ω / □, more preferably 1×10 8 ~1×10 9 The surface resistance may be Ω / □. Examples of the antistatic adhesive include adhesives disclosed in JP 2007-191532 A, JP 2008-007702 A, JP 2009-242745 A, and WO 2015 / 030186 A.

[0103] As the pressure-sensitive adhesive, one of these or a mixture of two or more thereof can be used.

[0104] The method for forming the pressure-sensitive adhesive layer using the pressure-sensitive adhesive is not particularly limited, and any known web coating method can be appropriately selected and used. As the web coating method, from the viewpoint of applying a coating material with good productivity by a roll-to-roll method, methods such as rod coating, roll coating, gravure coating, reverse coating, kiss reverse coating, and die coating are preferred.

[0105] The thickness of the pressure-sensitive adhesive layer is not particularly limited and can be appropriately selected taking into consideration the specific type of the target semiconductor manufacturing process film, its usage mode, and the properties of the pressure-sensitive adhesive used. The thickness of the pressure-sensitive adhesive layer may be generally about 1 to 30 μm, preferably about 5 to 25 μm, and more preferably about 10 to 20 μm. [Example]

[0106] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0107] Measurement method The following tests (i) to (iii) were carried out after conditioning the samples in an environment of 23±2°C temperature and 50±10% humidity for 16 hours or more, and then under the same temperature and humidity conditions unless otherwise specified.

[0108] (a) Tensile test: (A-1) Measurement of stress-strain curve in machine direction: In accordance with JIS K7127:1999, a tensile testing machine "Autograph AGS-1kNG (product name)" manufactured by Shimadzu Corporation was used to punch out samples from the multilayer film into the shape of the above-mentioned standard type 1B test piece (Figure 3 of the JIS standard) with the machine direction as the tensile direction. A tensile test was conducted at a tensile speed of 200 mm / min, and a stress-strain curve in the machine direction was obtained.

[0109] (A-2) Measurement of stress-strain curve in the transverse direction: A tensile test was carried out in the same manner as in (A-1) above, except that the samples used were punched so that the tensile direction was the transverse direction of the multilayer film, and a stress-strain curve in the transverse direction was obtained.

[0110] (A-3) Calculation of strain tensile stress (unit: MPa): In accordance with Section 10.1 of JIS K7161-1:2014, the 5% machine direction strain tensile stress (referred to as "5% MD" in the table), the 10% machine direction strain tensile stress (referred to as "10% MD" in the table), the 25% machine direction strain tensile stress (referred to as "25% MD" in the table), and the 100% machine direction strain tensile stress (referred to as "100% MD" in the table) were calculated from the obtained machine direction stress-strain curve. Similarly, from the obtained transverse stress-strain curves, the 5% strain tensile stress in the transverse direction (marked as "5% CD" in the table), the 10% strain tensile stress in the transverse direction (marked as "10% CD" in the table), the 25% strain tensile stress in the transverse direction (marked as "25% CD" in the table), and the 100% strain tensile stress in the transverse direction (marked as "100% CD" in the table) were calculated.

[0111] The ratio of the strain tensile stress in the machine direction to the strain tensile stress in the transverse direction measured by the above-mentioned test (a) tensile test method may be preferably 0.7 to 1.3, more preferably 0.8 to 1.2, and even more preferably 0.9 to 1.1, at any of 5%, 10%, 25%, and 100%, from the viewpoint of ensuring that the film is uniformly stretched in the expanding step.

[0112] (b) Heat seal initiation temperature (heat resistance): Measurements were performed using JIS Z1707:2019, Section 7.4, Heat Seal Strength Test. Using a heat seal bar calibrated with a surface thermometer, two sample pieces taken from the multilayer film were heat-sealed together, with the glossy side (the side facing the first chill roll 5) facing each other. The seal area was 15 mm x 10 mm, the seal pressure was 0.20 MPa, the seal time was 1 second, and the seal temperature was adjusted to allow for the interpolation of the heat seal initiation temperature. The long side of the test piece was aligned parallel to the machine direction. The heat-sealed samples were then conditioned for at least 16 hours at a temperature of 23 ± 2°C and humidity of 50 ± 10%. Then, under the same conditions, a T-peel test was performed at a peel speed of 200 mm / min. Peel strength was measured at each seal temperature, and a seal temperature-peel strength curve was created. The temperature at which the peel strength reached 300 g / 15 mm was defined as the heat seal initiation temperature.

[0113] From the viewpoint of heat resistance, the heat seal initiation temperature measured by the above-mentioned test (ii) heat seal initiation temperature (heat resistance) method may be preferably 90°C or higher, more preferably 95°C or higher, and even more preferably 100°C or higher.

[0114] (c) Blocking strength (blocking resistance): Two sample pieces measuring 30 cm in the machine direction and 12 cm in the horizontal direction were taken from the multilayer film, and the glossy surfaces (the surfaces that were on the first chill roll 5 side) of the two sample pieces were overlapped so that the two sample pieces were approximately aligned, and the pieces were set in a jig with a contact area of ​​10 × 10 cm, and a load of 36 g / cm was applied. 2Blocking was performed under conditions of 100°C, a temperature of 60°C, and 3 hours. Figure 4 shows a conceptual diagram of the state in which two stacked sample pieces were set on the jig. The top view is the plan view, Figure 4(a) is a right side view, and Figure 4(b) is a front view. On the surface of a lower metal plate 11 measuring 15 cm x 15 cm and 3 mm thick, a lower silicone rubber sheet 12 measuring 10 cm x 10 cm and 1 mm thick, a stack of two sample pieces 13, an upper silicone rubber sheet 14 measuring 10 cm x 10 cm and 1 mm thick, and an upper metal plate 15 measuring 15 cm x 15 cm and 3 mm thick were set in this order with each side approximately parallel to each other, and a weight 16 was placed on the surface of the upper metal plate 15. After blocking, the two stacked sample pieces 13 were removed from the jig and conditioned for 16 hours or more at a temperature of 23±2°C and a humidity of 50±10%. Then, under the same conditions, a T-peel test was conducted at a peel rate of 20 mm / min to measure the peel strength. A load cell with a rated capacity of 2 kg was used.

[0115] The blocking strength measured by the above-mentioned test (c) blocking strength (blocking resistance) method may be, from the viewpoint of blocking resistance, preferably 2.0 N / 10 cm or less, more preferably 1.6 N / 10 cm or less, even more preferably 1.2 N / 10 cm or less, still more preferably 0.8 N / 10 cm or less, and most preferably 0.4 N / 10 cm or less.

[0116] Raw materials used (A) Polyolefin: (A1-1) Polyethylene "Kernel KC581 (trade name)" from Japan Polyethylene Co., Ltd., melt mass flow rate (190°C, 21.18N) 10g / 10min, density 919kg / m 3 , melting point 108°C, enthalpy of fusion 104 J / g. (A1-2) Evolue SP2520 (trade name) polyethylene from Prime Polymer Co., Ltd., melt mass flow rate (190°C, 21.18N) 1.9g / 10min, density 925kg / m 3It has a melting point of 121°C, a melting enthalpy of 154 J / g, and a sub-peak with a peak top temperature of 107°C.

[0117] (A2-1) Novatec MA1B (trade name), a propylene homopolymer manufactured by Japan Polypropylene Corporation, with a melt mass flow rate (230°C, 21.18N) of 21 g / 10 min, a melting point of 162°C, and a melting enthalpy of 104 J / g. (A2-2) Propylene-ethylene random copolymer "Nobatec MG03B (trade name)" manufactured by Japan Polypropylene Corporation, melt mass flow rate (230°C, 21.18N) 30g / 10min, melting point 153°C, fusion enthalpy 89J / g.

[0118] (B) Hydrogenated block copolymer of aromatic vinyl compound and conjugated diene compound: (B-1) Asahi Kasei Corporation's hydrogenated block copolymer of styrene and 1,3-butadiene (styrene-ethylene-butene-styrene copolymer) "Tuftec H1052 (trade name)", melt mass flow rate (230°C, 21.18N) 13.0 g / 10 min, content of structural units derived from styrene 20% by mass. (B-2) Asahi Kasei Corporation's hydrogenated block copolymer of styrene and 1,3-butadiene (styrene-ethylene-butene-styrene copolymer) "Tuftec P1083 (trade name)", melt mass flow rate (190°C, 21.18N) 3.0g / 10min, content of structural units derived from styrene 20% by mass. (B-3) Kuraray Co., Ltd., hydrogenated block copolymer of styrene and isoprene (styrene-ethylene-ethylene-propylene-styrene copolymer) "Hybrar 7311F (trade name)", melt mass flow rate (190°C, 21.18N) 0.5g / 10 minutes, melt mass flow rate (230°C, 21.18N) 2g / 10 minutes, content of structural units derived from styrene 12% by mass.

[0119] Example 1 A film-making apparatus, the conceptual diagram of which is shown in Figure 3, was used, namely, a film-making apparatus equipped with a two-kind, three-layer multi-manifold coextrusion T-die 1, an extruder 2 for both outer layers, an extruder 3 for the middle layer, and a take-up device having a nipping mechanism with a first chill roll (mirror-finish metal roll) 5 and a nip roll (matt-finish silicone rubber roll) 6. The above (A1-1) was continuously coextruded from the coextrusion T-die 1 as both outer layers by extruder 2, and the above (B-1) was continuously coextruded from the coextrusion T-die 1 as a two-kind, three-layer molten multilayer film 4 by extruder 3. The extruded molten multilayer film 4 was nipped by the rotating nip roll 6 and pressed against the rotating first chill roll 5, after which it was sent from the first chill roll 5 to the next rotating roll 7, and a multilayer film 8 was produced, each with a thickness of 6 μm for both outer layers, a thickness of 88 μm for the middle layer, and an overall thickness of 100 μm. The resin temperature at the T-die exit was 230°C, the surface temperature of the first chill roll 5 was 25°C, the temperature of the cooling water flowing through the nip roll 6 was 20°C, and the take-up speed was 5 m / min. Annealing was performed at a temperature of 40°C (humidity was not controlled) for 24 hours, and then conditioning was performed at a temperature of 23±2°C and a humidity of 50±10% for 16 hours or more. After that, the above tests (A) to (C) were performed under the same temperature and humidity conditions unless otherwise noted. The results are shown in Table 1.

[0120] Examples 2-8 A multilayer film was produced in the same manner as in Example 1, except that the layer structure of the multilayer film was changed as shown in Table 1, and the above tests (a) to (c) were carried out. The results are shown in Table 1.

[0121] [Table 1]

[0122] Figure 5 shows the stress-strain curve in the machine direction for Example 1, and Figure 6 shows the stress-strain curve in the transverse direction for Example 1. It was found that the stress of the multilayer film of Example 1 increased monotonically and gradually at strains of approximately 50 to 200% in both the machine direction and the transverse direction, and that the stress-strain curve was very similar to that of a film made of a flexible polyvinyl chloride resin composition. Therefore, it was considered that the multilayer film of Example 1 had excellent expandability, similar to that of a film made of a flexible polyvinyl chloride resin composition.

[0123] Example 9 Onto the matte surface of the multilayer film of Example 1 (the surface that was on the nip roll 6 side), an applicator was used to apply an adhesive layer-forming paint consisting of 333 parts by mass (100 parts by mass in terms of solid content) of Fujikura Chemical Co., Ltd.'s transparent adhesive "ACRYBASE LKG-1013 (trade name)", 1 part by mass of Fujikura Chemical Co., Ltd.'s isocyanate-based curing agent "CL-201 (trade name)", and 222 parts by mass of ethyl acetate, so that the film thickness after drying would be 10 μm, and the film was dried at a temperature of 85°C to form an adhesive layer, and a semiconductor manufacturing process film was obtained.

[0124] The haze of the semiconductor manufacturing process film of Example 9 (measured in accordance with JIS K7136:2000 using a turbidity meter "NDH2000 (product name)" manufactured by Nippon Denshoku Industries Co., Ltd., with light incident on the glossy side of the multilayer film (the side that was on the side of the first chill roll 5)) was 3.4%.

[0125] The multilayer film of the present invention fundamentally solves the problems caused by plasticizers in films of flexible polyvinyl chloride resin compositions by not incorporating plasticizers, and has been found to have high flexibility and good blocking resistance. It has also been found that preferred multilayer films of the present invention also have good expandability and heat resistance, and exhibit a good balance between flexibility and expandability, blocking resistance, and heat resistance. It has also been found that preferred multilayer films of the present invention have sufficient transparency to be used as a film substrate for films used in semiconductor manufacturing processes. Therefore, it has been considered that the multilayer film of the present invention can be suitably used as a film substrate for films used in semiconductor manufacturing processes, such as dicing films, backgrinding films, and die attach films.

[0126] Example 10 The multilayer film of Example 1 was subjected to electron beam irradiation treatment under the condition of an irradiation dose of 80 KGy, to obtain a multilayer film of Example 10 (multilayer film subjected to electron beam irradiation treatment).

[0127] The multilayer films of Examples 1 and 10 were mechanically cut using an office paper cutter. The cut surfaces of the multilayer films were visually inspected, and the number of so-called whiskers that occurred was compared between Example 1 and Example 10. The number of whiskers that occurred in Example 10 was about one-fifth of that in Example 1.

[0128] It has been confirmed that when the resin constituting both the (α1) first polyolefin layer and the (α2) second polyolefin layer of the multilayer film of the present invention is the above-mentioned ethylene-based resin, electron beam irradiation treatment can suppress the generation of so-called whiskers when mechanically cutting. [Brief explanation of the drawings]

[0129] [Figure 1] 1 is a DSC curve of polyethylene (A1-1) used in the examples. [Figure 2] 1 is a DSC curve of the propylene homopolymer (A2-1) used in the examples. [Figure 3]FIG. 1 is a conceptual diagram of an apparatus used for film formation in the examples. [Figure 4] FIG. 1 is a conceptual diagram showing a state in which a sample is set on a jig used in evaluating blocking resistance. [Figure 5] 1 is a machine direction stress-strain curve for Example 1. [Figure 6] 1 is a transverse stress-strain curve of Example 1. [Explanation of symbols]

[0130] 1: Co-extrusion T-die 2: Extruder for both outer layers 3: Intermediate layer extruder 4: Multilayer film in molten state 5: First chill roll (mirror-finished metal roll) 6: Nip roll (matt silicone rubber roll) 7: Rotating roll 8: Multilayer film 11: Lower metal plate 12: Lower silicone rubber sheet 13: Two sample pieces stacked on top of each other 14: Upper silicone rubber sheet 15: Upper metal plate 16: Weight

Claims

1. A multilayer film for a film substrate of a semiconductor processing film, (α1) a first polyolefin layer, (β) an elastomer layer, and (α2) a second polyolefin layer are directly laminated in this order; the first polyolefin layer (α1) is made of polyethylene or polypropylene, the (β) elastomer layer is made of a hydrogenated block copolymer of an aromatic vinyl compound and a conjugated diene compound, The second polyolefin layer (α2) is made of polyethylene or polypropylene. The multilayer film.

2. The first polyolefin layer (α1) has a density of 910 to 940 kg / m ３ and The second polyolefin layer (α2) has a density of 910 to 940 kg / m ３ consisting of polyethylene The multilayer film for use as a film substrate for semiconductor processing films according to claim 1 .

3. The first polyolefin layer (α1) is made of polypropylene, and The second polyolefin layer (α2) is made of polypropylene. The multilayer film for use as a film substrate for semiconductor processing films according to claim 1 .

4. The thickness of the first polyolefin layer (α1) is 1 μm or more, the thickness of the (β) elastomer layer is 70% or more of the total thickness of the multilayer film, The thickness of the second polyolefin layer (α2) is 1 μm or more. The multilayer film for use as a film substrate for semiconductor processing films according to claim 1.

5. The multilayer film for film substrate of semiconductor process film according to claim 4, wherein the thickness of the multilayer film as a whole is 50 to 300 μm.

6. A semiconductor manufacturing process film, comprising the multilayer film for a film substrate of a semiconductor manufacturing process film according to any one of claims 1 to 5.

7. The method for producing a multilayer film for use as a film substrate for semiconductor processing films according to claim 2, further comprising a step of irradiating the multilayer film with an electron beam.

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