Thermoplastic resin film, adhesive film and adhesive film for semiconductor manufacturing process

Abstract

To provide a film which is excellent in film formation property when a resin is formed into a film, and is also excellent in expandability, restorability and heat resistance of the obtained film.SOLUTION: A thermoplastic resin film contains a polyolefin-based resin as a thermoplastic resin and a styrenic elastomer, and satisfies the following conditions. (i) Both tensile elastic moduli in an MD direction and a TD direction are 300 MPa or less. (ii) A ratio (MD / TD) of the tensile elastic modulus in the MD direction to the tensile elastic modulus in the TD direction is 1.0 or more and 2.0 or less. (iii) A resilience in the MD direction is 70% or more.

Description

[Technical field]

[0001] The present invention relates to an adhesive film (tape) used in the semiconductor manufacturing process, an adhesive film (tape) such as a sticker, label, or marking film attached to a signboard, automobile, or the like to impart design features, a thermoplastic resin film suitable for use as a substrate for a decorative sheet, and an adhesive film having an adhesive layer provided on the thermoplastic resin film. [Background technology]

[0002] Conventionally, films made of polyvinyl chloride resin (hereinafter also referred to as "PVC-based films"), which have excellent colorability, processability, scratch resistance, weather resistance, etc., have been widely used as the substrate for adhesive films (tapes), such as stickers, labels, and marking films that are affixed to signs, automobiles, etc. to impart design features, and decorative sheets, etc.

[0003] The PVC film itself has rigidity, but a plasticizer is added to impart flexibility so that the film can function as an adhesive film. However, depending on the plasticizer used, the film has poor compatibility with the adhesive, and when the film is made into an adhesive film, the film has poor stability and the plasticizer bleeds out significantly. In addition, there is a tendency for the use of plasticizers to be more strictly regulated. Therefore, polyolefin resin films have come to be widely used as an alternative material to PVC films.

[0004] Furthermore, in the process of manufacturing semiconductors, adhesive films for semiconductor wafer processing are used when cutting semiconductor wafers, packages, etc., and due to the above-mentioned problems, the use of polyolefin-based resin films is increasingly being used. Films using PVC-based and polyolefin-based resins have been developed as films for use in such semiconductor manufacturing processes (for example, Patent Document 1). Patent Document 2 discloses a substrate film for use in semiconductor manufacturing processes that is provided with antistatic properties and has excellent flexibility and heat resistance.

[0005] Furthermore, in recent years, semiconductor elements have become smaller and thinner, and there is a tendency for the expandability of the film to be more demanding in the expansion process to expand the space between chips on the semiconductor wafer. As chips become smaller, chips and devices are more likely to be damaged due to contact between chips, which leads to a decrease in yield and thus has a greater impact on economic efficiency.

[0006] To solve these problems, Patent Documents 3 and 4 disclose substrate films for dicing that contain a large amount of an olefin-based elastomer or a styrene-based elastomer and have excellent expandability. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 9-8111 [Patent Document 2] JP 2020-84143 A [Patent Document 3] Patent Publication No. 2022-133959 [Patent Document 4] JP2015-130395A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0008] However, in the inventions described in Patent Documents 1 and 2, although polyolefin resins and olefin elastomers are the main components, the type and content thereof are not optimized, and it is presumed that the expandability is insufficient. In addition, the invention described in Patent Document 3 uses a large amount of styrene-based elastomer, and although the film has excellent recovery properties, the material and content are not optimized in consideration of the processability and handling properties of the film, and there is room for improvement in the balance of physical properties in the MD and TD directions and the type and content of the styrene-based elastomer. The invention described in Patent Document 4 uses an olefin-based elastomer and a styrene-based elastomer, and is presumed to be a flexible film with sufficiently excellent handling properties and recovery properties. However, since it is presumed that the main component of the thermoplastic resin is an elastomer, it is considered that there is room for improvement in terms of imparting heat resistance to the film as well as flexibility and recovery properties.

[0009] In view of the above problems, the present invention aims to provide a film that has excellent film-forming properties when molding a resin into a film, has excellent heat resistance and a good balance of physical properties in the MD and TD directions, has good expandability, and can be easily restored to a state close to that of the film before expansion when the expansion is interrupted and the film with the wafer fixed thereto is recovered. Another object of the present invention is to provide an adhesive film for semiconductor manufacturing processes that has excellent expandability and can ensure sufficient spacing between chips. [Means for solving the problem]

[0010] The present inventors have conducted extensive research into a film that has excellent film-forming properties when a resin is molded into a film, and that has excellent heat resistance and a balance of physical properties in the MD and TD directions when the film is obtained, has good expandability, and can be easily restored to a state close to that of the film before expansion when the expansion is interrupted and the film with the wafer fixed thereto is recovered. As a result, the present invention has been completed.

[0011] That is, the gist of the present invention is as follows. [1] A thermoplastic resin film comprising a polyolefin resin and a styrene elastomer as thermoplastic resins, and satisfying the following requirements: (i) The tensile modulus in both the MD and TD directions is 300 MPa or less (ii) The ratio of the tensile modulus in the MD direction to the TD direction (MD / TD) is 1.0 or more and 2.0 or less. (iii) MD recovery rate is 70% or more [2] The thermoplastic resin film according to [1], wherein the styrene-based elastomer contains a styrene-based elastomer (A) having a styrene component content of 10% by mass or more and 20% by mass or less and a styrene-based elastomer (B) having a styrene component content of 40% by mass or more and 60% by mass or less. [3] A thermoplastic resin film according to [1] or [2], in which the ratio (A / B) of the content of the styrene-based elastomer (A) to the content of the styrene-based elastomer (B) is within the range of 0.7 to 2.0. [4] The thermoplastic resin film according to any one of [1] to [3], wherein the polyolefin resin is a polypropylene resin. [5] The thermoplastic resin film according to [4], characterized in that the polypropylene-based resin contains a polypropylene-based resin having a crystalline melting peak of 140°C or higher. [6] The thermoplastic resin film according to [5], wherein the polypropylene-based resin having a crystalline melting peak of 140°C or higher is a homopolypropylene. [7] The thermoplastic resin film according to any one of [1] to [6] above is a thermoplastic resin film having at least three layers including a surface layer, a back layer and an intermediate layer. [8] An adhesive film comprising a thermoplastic resin film according to any one of [1] to [7] and an adhesive layer provided on at least one surface of the thermoplastic resin film. [9] The adhesive film for semiconductor manufacturing process according to [8], which is used in the semiconductor manufacturing process. Effect of the Invention

[0012] The present invention makes it possible to provide a film that has excellent film-forming properties when molding a resin into a film, and has excellent heat resistance and a balance of physical properties in the MD and TD directions of the obtained film, and also has excellent expandability, and can be easily restored to a state close to that of the film before expansion when the expansion is interrupted and the film with the wafer fixed thereto is recovered.In addition, the present invention makes it possible to provide an adhesive film for semiconductor manufacturing processes that has excellent expandability and can ensure sufficient spacing between chips. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be modified and implemented in various ways within the scope of the gist. In addition, when the expression "~" is used in this specification, it is used as an expression including the numerical values ​​or physical property values ​​before and after it.

[0014] One embodiment of the present invention is a thermoplastic resin film comprising a polyolefin resin and a styrene elastomer as thermoplastic resins, and satisfying the following requirements: (i) The tensile modulus in both the MD and TD directions is 300 MPa or less (ii) The ratio of the tensile modulus in the MD direction to the TD direction (MD / TD) is 1.0 or more and 2.0 or less. (iii) MD recovery rate is 70% or more

[0015] <Polyolefin resin> The thermoplastic resin film used in the present invention contains a polyolefin resin and a styrene elastomer as essential components. Polyolefin resins are preferably used from the viewpoints of availability, the comparative ease with which heat resistance and flexibility can be adjusted, and compatibility with the styrene elastomer described below. As the polyolefin resin, one or more resins selected from polypropylene resins, polyethylene resins, and olefin elastomers are preferably used from the viewpoints of availability, flexibility, ease of handling, economic efficiency, etc. Among them, polypropylene resins and polyethylene resins are preferred from the viewpoints of availability and economic efficiency, and because it is relatively easy to adjust the heat resistance and flexibility.

[0016] Examples of polypropylene-based resins include homopolymers of propylene (homopolypropylene), copolymers containing propylene as the main component and other monomers copolymerizable with propylene, and mixtures of these. Examples of the copolymers containing propylene as a main component and other monomers copolymerizable with propylene include random copolymers (random polypropylenes) and block copolymers (block polypropylenes) of propylene and ethylene or other α-olefins, and block or graft copolymers containing a rubber component. The α-olefin used as the other monomer copolymerizable with propylene preferably has 4 to 12 carbon atoms, and examples thereof include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-1-pentene, and 1-decene. One or a mixture of two or more of these is used. Among polypropylene-based resins, it is preferable to use homopolypropylene and random polypropylene because it is easy to adjust flexibility and heat resistance. Among homopolypropylene and random polypropylene, it is more preferable to use one that shows a crystalline melting peak of 140°C or more from the viewpoint of imparting heat resistance to the film. By having a crystalline melting peak of 140°C or more, it is possible to impart sufficient heat resistance to the obtained thermoplastic resin film. It is more preferably 145°C or more, and even more preferably 150°C or more. The crystalline melting peak can be measured using a differential scanning calorimeter according to "JIS K 7122". As a resin having a crystal melting peak of 140° C. or more, homopolypropylene is preferably used. Commercially available homopolypropylene products include, for example, Novatec PP "MA3U" and Novatec PP "FY6HA" (both manufactured by Japan Polypropylene Corporation), PC412A, PC600A, PC600S, PLA00A (all manufactured by SunAllomer Corporation), F-730NV, F-744NP (all manufactured by Prime Polypropylene Corporation), Sumitomo Noblen "WF836DG3", and Sumitomo Noblen "FLX80H5" (all manufactured by Sumitomo Chemical Co., Ltd.). The random polypropylene or homopolypropylene may be used alone or in combination of two or more kinds. They can be appropriately selected as necessary in consideration of film formability when obtaining a thermoplastic resin film, heat resistance, flexibility, etc. of the obtained film.

[0017] Examples of polyethylene-based resins include ethylene homopolymers, copolymers of ethylene mainly composed of ethylene and other monomers copolymerizable therewith (low-density polyethylene (LDPE), high-pressure low-density polyethylene, linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), ethylene-based copolymers obtained by polymerization using a metallocene catalyst (metallocene-based polyethylene), ethylene-vinyl acetate copolymers, ethylene-methyl (meth)acrylate copolymers, ethylene-ethyl (meth)acrylate copolymers, ethylene-butyl (meth)acrylate copolymers, ethylene-(meth)acrylic acid copolymers, and metal ion crosslinked resins (ionomers) of ethylene-(meth)acrylic acid copolymers. Among these, it is preferable to use high density polyethylene (HDPE), low density polyethylene (LDPE), and linear low density polyethylene (LLDPE) from the viewpoints of ease of availability, ease of handling of the resin, and ease of adjusting the flexibility of the resulting film.

[0018] The olefin-based elastomer is a soft resin containing a polyolefin-based resin and a rubber component, and may be one in which the rubber component is dispersed in the polyolefin-based resin, or one in which the two are copolymerized with each other. Specific examples of olefin-based elastomers include amorphous elastic copolymers mainly composed of olefins, such as ethylene-propylene copolymer elastomers, ethylene-1-butene copolymer elastomers, ethylene-propylene-1-butene copolymer elastomers, ethylene-1-hexene copolymer elastomers, ethylene-1-octene copolymer elastomers, ethylene-styrene copolymer elastomers, ethylene-norbornene copolymer elastomers, propylene-1-butene copolymer elastomers, ethylene-propylene-non-conjugated diene copolymer elastomers, ethylene-1-butene-non-conjugated diene copolymer elastomers, and ethylene-propylene-1-butene-non-conjugated diene copolymer elastomers, as well as derivatives and acid-modified derivatives thereof.

[0019] The melt flow rates of the polypropylene resins, polyethylene resins, olefin elastomers, etc. described above are appropriately selected depending on the molding method and application, but are preferably 0.1 to 50 g / 10 min as measured under a load of 2.16 kg at a temperature of 190° C. or 230° C. If it is 0.1 g / 10 min or more, the formability of the film is good, and if it is 50 g / 10 min or less, it is possible to maintain good thickness precision of the film. The rate is more preferably 0.5 to 40 g / 10 minutes, and further preferably 1.0 to 30 g / 10 minutes.

[0020] Regarding the strength of polypropylene-based resins, polyethylene-based resins, olefin-based elastomers, etc., the tensile modulus of a film obtained from these resins alone is preferably within the range of 50 to 2000 MPa. If the tensile modulus is within the range of 50 to 2000 MPa, it is possible to impart appropriate flexibility to the film of the present invention. It is more preferably within the range of 80 to 1900 MPa, and even more preferably within the range of 100 to 1800 MPa. The polyolefin resin may be used alone or in combination of two or more kinds. It can be appropriately selected as needed in consideration of the flexibility, heat resistance, film formability, etc. of the resulting thermoplastic resin film.

[0021] <Styrene-based elastomer> The thermoplastic resin film used in the present invention contains a styrene-based elastomer as an essential component in addition to the polyolefin-based resin described above. By including the styrene-based elastomer, it becomes easy to impart flexibility and restorability to the obtained film.

[0022] The styrene-based elastomer is preferably a block copolymer represented by the following formula (I) or (II). X-(YX)n …(I) (XY)n …(II) In general formulas (I) and (II), X is an aromatic vinyl polymer block (hereinafter, styrene component) typified by styrene, and in formula (I), the degree of polymerization at both ends of the molecular chain may be the same or different. Y is at least one selected from a butadiene polymer block, an isoprene polymer block, a butadiene / isoprene copolymer block, a hydrogenated butadiene polymer block, a hydrogenated isoprene polymer block, a hydrogenated butadiene / isoprene copolymer block, a partially hydrogenated butadiene polymer block, a partially hydrogenated isoprene polymer block, and a partially hydrogenated butadiene / isoprene copolymer block. n is an integer of 1 or more.

[0023] Specific examples include styrene-ethylene-butylene-styrene copolymer, styrene-ethylene-propylene-styrene copolymer, styrene-ethylene-ethylene-propylene-styrene copolymer, styrene-butadiene-butene-styrene copolymer, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, styrene-hydrogenated butadiene diblock copolymer, styrene-hydrogenated isoprene diblock copolymer, styrene-butadiene diblock copolymer, styrene-isoprene diblock copolymer, etc., among which styrene-ethylene-butylene-styrene copolymer, styrene-ethylene-propylene-styrene copolymer, styrene-ethylene-ethylene-propylene-styrene copolymer, and styrene-butadiene-butene-styrene copolymer are preferred. Also, a block copolymer of styrene-ethylene-butylene-crystalline olefin copolymer can be used. The styrene-based elastomer may be used alone or in combination of two or more kinds. It can be appropriately selected as necessary in consideration of film-forming properties when obtaining a thermoplastic resin film, and flexibility, handling properties, and expandability of the obtained film.

[0024] The melt flow rate of the styrene-based elastomer (measured under a temperature condition of 230°C and a load of 2.16 kg) is preferably 0.1 to 10 g / 10 min, more preferably 0.15 to 9 g / 10 min, and particularly preferably 0.2 to 8 g / 10 min. If the melt flow rate of the styrene-based elastomer is less than 0.1 g / 10 minutes or exceeds 10 g / 10 minutes, the compatibility with the polyolefin-based resin decreases and the film-forming properties deteriorate, so that sufficient flexibility and expandability may not be achieved.

[0025] In the present invention, it is preferable to use two or more of the above-mentioned styrene-based elastomers in combination, and it is more preferable to use a styrene-based elastomer (A) having a styrene component content in the range of 10% by mass or more and 20% by mass or less in combination with a styrene-based elastomer (B) having a styrene component content of 40% by mass or more and 60% by mass or less in combination. The inclusion of the styrene-based elastomer (A) makes it easy to impart flexibility and recovery to the film, while the inclusion of the styrene-based elastomer (B) makes it easy to maintain recovery while maintaining appropriate flexibility. The content of styrene components and other components is as follows: 1 H-NMR and 13 It can be measured by C-NMR. Here, the "styrene component content" refers to the content ratio (mass%) of aromatic vinyl polymer blocks, typically styrene, based on the mass of the styrene-based elastomer.

[0026] Examples of commercially available styrene-based elastomers (A) include Tuftec H1221, Tuftec H1062, Tuftec H1521, Tuftec H1052, and Tuftec P1083 (all manufactured by Asahi Kasei Corporation), Hybler 2004F, Hybler 2063, Hybler 5125, Hybler 5127, Hybler 7125F, and Hybler 7311F (all manufactured by Kuraray Co., Ltd.), Dynaron 1320P, Dynaron 1321P, Dynaron 4600P, Dynaron 8600P, and Dynaron 8300P (all manufactured by ENEOS Materials Corporation).

[0027] Examples of commercially available styrene-based elastomers (B) include Tuftec H1051, Tuftec H1517, Tuftec P5051 (all manufactured by Asahi Kasei Corporation), and Dynaron 9901P (all manufactured by ENEOS Materials Corporation).

[0028] Furthermore, when the styrene-based elastomer (A) and the styrene-based elastomer (B) are used in combination, the content ratio (A / B) thereof is preferably in the range of 0.7 to 2.0. By setting the content ratio (A / B) in the range of 0.7 to 2.0, it becomes easy to set the ratio of the elastic modulus in the MD direction to the TD direction (MD / TD) of the obtained film in the range of 1.0 to 2.0. The content ratio (A / B) is more preferably in the range of 0.8 to 1.9, and even more preferably in the range of 1.0 to 1.8.

[0029] <Other resins> To the thermoplastic resin film of the present invention, a cyclic olefin resin, a polymethylpentene resin, etc. may be added as a resin other than the above-mentioned olefin resin and styrene elastomer.

[0030] Examples of cyclic olefin resins include norbornene polymers, vinyl alicyclic hydrocarbon polymers, and cyclic conjugated diene polymers. Among these, norbornene polymers are preferred. Examples of norbornene polymers include ring-opening polymers of norbornene monomers and norbornene copolymers obtained by copolymerizing norbornene monomers with α-olefins such as ethylene. Hydrogenated products of these may also be used.

[0031] <Other ingredients> In order to impart the required performance to the resulting film, the thermoplastic resin film of the present invention may contain various additives other than the polyolefin-based resin and styrene-based elastomer to impart heat resistance, weather resistance, antistatic performance, etc. Specific examples of the additives that may be used include antistatic agents, antioxidants, neutralizing agents, lubricants, antiblocking agents, plasticizers, heat stabilizers, light stabilizers, dyes and pigments, crystal nucleating agents, ultraviolet absorbers, fillers, inorganic fillers that impart rigidity, and elastomers other than those mentioned above that impart flexibility, within the scope of not impairing the effects of the present invention. When it is necessary to impart different properties to each layer of the film, various additives can be added to each layer.

[0032] Any known antistatic agent can be used as the antistatic agent. However, from the viewpoints of compatibility with the resulting film, imparting long-term antistatic performance, and suppressing bleed-out of the antistatic agent over time, it is preferable to use a polymer-type antistatic agent.

[0033] Known polymer-type antistatic agents can be used, for example, block copolymers of a hydrophobic block and a hydrophilic block. In the polymer-type antistatic agent, the hydrophobic block and the hydrophilic block form a block copolymer through ester bonds, ether bonds, amide bonds, imide bonds, urethane bonds, urea bonds, etc.

[0034] The hydrophobic block may be, for example, a polyolefin block, and the polyolefin block may be, for example, a block made of polyethylene, polypropylene, or an ethylene-propylene copolymer.

[0035] A hydrophobic block such as a polyolefin block has polar groups such as a carbonyl group, a hydroxyl group, and an amino group at both ends thereof. A block copolymer of a hydrophobic block and a hydrophilic block can be obtained by polymerizing the polar groups at both ends of the hydrophobic block with the carbonyl group, the hydroxyl group, and the amino group present at both ends of the hydrophilic block, or by crosslinking the polar groups with a diisocyanate, a diglycidyl ether, or the like.

[0036] Hydrophilic blocks can include, for example, polyether blocks, polyether-containing hydrophilic polymer blocks, cationic polymer blocks, and anionic polymer blocks. In addition, the polymer-type antistatic agent may contain an alkali metal or alkaline earth metal salt, a quaternary ammonium salt, a surfactant, an ionic liquid, etc., in order to further improve the antistatic properties, within the range that does not impair the effects of the present invention.

[0037] Commercially available polyether-polyolefin block copolymers, which are one type of polymeric antistatic agent, include, for example, Pelestat 300, Pelestat 230, Pelestat UC, Pelestat PVL, and Pelestat PVH (all manufactured by Sanyo Chemical Industries, Ltd.).

[0038] As the ultraviolet absorbing agent, known agents can be used, and examples thereof include benzotriazole-based ultraviolet absorbing agents, benzophenone-based ultraviolet absorbing agents, and triazine-based ultraviolet absorbing agents.

[0039] As the light stabilizer, a known one can be used, and examples thereof include hindered amine light stabilizers.

[0040] As the lubricant or antiblocking agent, known agents such as organic particles, inorganic particles, and amide compounds can be used. In addition, it is preferable to use a silicone-olefin copolymer, since it has excellent compatibility with the above-mentioned polyolefin resin, prevents defects caused by bleeding out on the surface of the obtained film, and can provide long-term scratch resistance and slipperiness.

[0041] <Thermoplastic resin film> The thermoplastic resin film of the present invention is a thermoplastic resin film containing the above-mentioned polyolefin-based resin and styrene-based elastomer, and is characterized by satisfying the following: (i) The tensile modulus in both the MD and TD directions is 300 MPa or less (ii) The ratio of the tensile modulus in the MD direction to the TD direction (MD / TD) is 1.0 or more and 2.0 or less. (iii) MD recovery rate is 70% or more

[0042] The thermoplastic resin film of the present invention is preferably a thermoplastic resin film having at least three layers including a surface layer, a back layer, and an intermediate layer. This configuration of the surface layer, the back layer, and the intermediate layer is preferable because it makes it easier to adjust the film formability and the flexibility and blocking property of the obtained film. The surface layer and the back layer may be layers made of the same resin composition, or layers made of different resin compositions. From the viewpoint of film-forming properties, it is preferable to use layers made of the same resin composition. In addition, from the viewpoint of compatibility with the intermediate layer and adhesion between layers, it is preferable to use a resin similar to or the same as the resin used in the intermediate layer. The resin composition constituting the surface layer and the back layer preferably contains the above-mentioned polyolefin resin and styrene elastomer. In the surface layer and the back layer, when the total mass of the polyolefin resin and styrene elastomer constituting each layer is 100 mass%, it is preferable to adjust the polyolefin resin to 70 to 100 mass% and the styrene elastomer to 0 to 30 mass%. By setting the above ratio, it becomes easy to suppress the film from sticking to the transport roll when forming the film, and further, it becomes easy to improve the blocking property between the films without impairing the flexibility and recovery of the obtained film. More preferably, the polyolefin resin is 75 to 100% by mass and the styrene elastomer is 0 to 25% by mass, and even more preferably, the polyolefin resin is 80 to 100% by mass and the styrene elastomer is 0 to 20% by mass. The ratio of the polyolefin resin and the styrene elastomer constituting the back layer is also preferably within the same range. As the polyolefin resin contained in each layer in the front layer and the back layer, it is preferable to use homopolypropylene or random polypropylene because it is easy to adjust the flexibility and heat resistance as described above, and it is more preferable to use one that shows a crystalline melting peak of 140 ° C or more from the viewpoint of imparting heat resistance to the film among homopolypropylene and random polypropylene. As the one that shows a crystalline melting peak of 140 ° C or more, it is preferable to use homopolypropylene described in the section on polyolefin resins from the viewpoint of heat resistance and ease of availability. In addition, it is more preferable to use random polypropylene and homopolypropylene in combination because it is easy to adjust the flexibility and heat resistance of the film. When the total mass of the polyolefin resin is 100 mass%, it is preferable that the random polypropylene is 30 to 100 mass% and the homopolypropylene is 0 to 70 mass%, and more preferably that the random polypropylene is 40 to 100 mass% and the homopolypropylene is 0 to 60 mass%. By setting the contents of the random polypropylene and the homopolypropylene in such ranges, it is possible to impart heat resistance without impairing the flexibility of the film.

[0043] The intermediate layer preferably contains a polyolefin resin and a styrene elastomer, as in the front and back layers, but it is preferable to adjust the polyolefin resin to 20-65% by mass and the styrene elastomer to 35-80% by mass when the total mass of the polyolefin resin and the styrene elastomer constituting the intermediate layer is 100% by mass. By adjusting the ratios as above, it is possible to improve the flexibility and restorability of the obtained film. More preferably, the polyolefin resin is in the range of 25-60% by mass and the styrene elastomer is in the range of 40-75% by mass, and even more preferably, the polyolefin resin is in the range of 30-55% by mass and the styrene elastomer is in the range of 45-70% by mass. As the types of polyolefin resin and styrene elastomer constituting each layer, those described in the respective sections are preferably used. As the polyolefin resin contained in the intermediate layer, homopolypropylene and random polypropylene are preferably used because the flexibility and heat resistance can be easily adjusted, as in the front and back layers. Among homopolypropylene and random polypropylene, it is more preferable to use one that shows a crystal melting peak of 140°C or more from the viewpoint of imparting heat resistance to the film. As the one that shows a crystal melting peak of 140°C or more, it is preferable to use homopolypropylene described above in the section on polyolefin resins from the viewpoint of heat resistance and ease of availability. In addition, it is more preferable to use random polypropylene and homopolypropylene in combination, because it is easy to adjust the flexibility and heat resistance of the film. When the total mass of the polyolefin resins is 100 mass%, it is preferable that the random polypropylene is 30 to 100 mass% and the homopolypropylene is 0 to 70 mass%, and more preferably that the random polypropylene is 40 to 100 mass% and the homopolypropylene is 0 to 60 mass%. By setting the contents of the random polypropylene and homopolypropylene in such ranges, it is possible to impart heat resistance without impairing the flexibility of the film. The random polypropylene and homopolypropylene used in the front layer, back layer and intermediate layer may be the same or different, and the content of each may be the same or different. They can be appropriately selected and used in consideration of the performance required for the obtained film. However, it is preferable that the intermediate layer contains the same resin as that used in the front layer and back layer from the viewpoint of improving the adhesion between each layer.

[0044] The thermoplastic resin film of the present invention preferably has a basic structure of a three-layer film having a front layer, a back layer, and an intermediate layer. By using a three-layer structure consisting of a front layer, a back layer, and an intermediate layer, it is possible to impart performance to each layer, such as improving the flexibility and recovery of the film and the blocking properties between films, making it easier to obtain a film that is suitable for use in the semiconductor manufacturing process. In this three-layer film configuration, the resin compositions constituting the front layer and the back layer may be the same or different. The intermediate layer may be composed of two or more layers. In this case, a film configuration of three or more layers is also included. In this case, all layers of the intermediate layer composed of two or more layers may be layers composed of the same resin composition or may be different layers. From the viewpoint of productivity and economic efficiency of the film, it is preferable that the film is a three-layer film composed of a front layer, a back layer, and one intermediate layer. In this case, whether the film is a two-kind three-layer film in which the front layer and the back layer are composed of the same resin composition, or a three-kind three-layer film in which the front layer and the back layer are composed of different resin compositions, can be appropriately selected as necessary in consideration of the performance and use of each layer of the front and back of the film required, and the processability and adhesion when providing an adhesive layer or a printed layer described later.

[0045] The total thickness of the thermoplastic resin film of the present invention is preferably 30 to 250 μm. If the thickness is 30 μm or more, the film forming property during film production and the handleability of the obtained film are good, and flexibility and heat resistance can be maintained at a good level, and if the thickness is 250 μm or less, the handleability and processability of the film in the step of laminating a printing layer or an adhesive layer on the film can be maintained at a good level. The total thickness of the thermoplastic resin film of the present invention is more preferably 40 to 230 μm, and further preferably 50 to 210 μm.

[0046] The thickness of each of the front layer and the back layer is preferably within the range of 1 to 30% of the total thickness of the thermoplastic resin film. By making it 1% or more of the total thickness, it is possible to impart the effect of suppressing blocking between the films, and by making it 30% or less, it is preferable that the flexibility of the obtained film is not impaired. More preferably, it is within the range of 3 to 25%, and further preferably within the range of 5 to 20%. The thickness of each of the front layer and the back layer may be the same thickness or different thicknesses as long as it can suppress the performance required for each of the front layer and the back layer of the obtained thermoplastic resin film and the blocking between the films. From the viewpoint of the productivity and economic efficiency of the film, it is preferable that the thickness of the front layer and the back layer is the same thickness.

[0047] The tensile modulus of the thermoplastic resin film of the present invention is preferably within the range of 50 to 1500 MPa. If it is 50 MPa or more, sufficient rigidity is imparted to the film, so that good handleability can be maintained, and if it is 1500 MPa or less, good processability of the film in the step of laminating an adhesive layer on the film can be maintained, and further, the load applied to the film and the device during expansion can be made appropriate. It is more preferably within the range of 50 to 1000 MPa, and even more preferably within the range of 50 to 500 MPa. The elastic modulus of the film in both the extrusion direction (MD) and the direction perpendicular to the extrusion direction (TD) is preferably within the above ranges. By having both within the above ranges, the film can be easily handled, and the ratio of the elastic modulus in the MD direction to the TD direction (MD / TD), which will be described later, can be easily adjusted within a desired range. The ratio of the tensile modulus of elasticity in the MD direction to the tensile modulus of elasticity in the TD direction (MD / TD) of the thermoplastic resin film of the present invention must be 1.0 or more and 2.0 or less. By having the ratio of the tensile modulus of elasticity (MD / TD) in the range of 1.0 or more and 2.0 or less, when the film is expanded during the semiconductor manufacturing process, it is possible to uniformly expand the gap between the cleaved wafers, and it is possible to suppress defects when picking up the wafers and a decrease in yield. It is more preferably in the range of 1.0 or more and 1.8 or less, and even more preferably in the range of 1.0 or more and 1.6 or less. The thermoplastic resin film of the present invention is required to have a restoration rate of 70% or more in the method described later in the Examples section. By having a restoration rate of 70% or more, when the expansion is interrupted and the film with the wafer fixed thereto is recovered, it becomes possible to easily restore the film to a state close to that before the expansion, and the film with the wafer fixed thereto becomes easy to recover and store. The restoration rate is more preferably 72% or more, and even more preferably 74% or more. The tensile elongation at break of the thermoplastic resin film of the present invention is preferably 300% or more. If the tensile elongation at break is 300% or more, breakage during handling of the film is suppressed, and therefore defects due to breakage are suppressed even when adhesive processing or the like is performed, and breakage during expansion is less likely to occur in the expansion step in the semiconductor manufacturing process, which is preferable. It is more preferably 400% or more, and even more preferably 500% or more. The tensile elongation at break can be measured by the same method as that described in the section on the measurement method of tensile elongation at break described later.

[0048] The thermoplastic resin film of the present invention can be formed by any known method, but it is preferable to use a melt extrusion method. Among the melt extrusion methods, a T-die molding method in which a molten resin is extruded from an extruder having a T-die and cooled and solidified to obtain a film is more preferable.

[0049] In order to obtain a film, it is preferable to use a co-extrusion T-die molding method using multiple extruders. By using a co-extrusion T-die molding method using multiple extruders, it is possible to obtain a multi-layer film, and it is possible to make the front and back layers of the same resin composition, or to make the front and back layers of resin compositions with different properties. Furthermore, it is also possible to make a multi-layer thermoplastic resin with characteristics only in the intermediate layer. Furthermore, by extruding the same resin from all the extruders, it is possible to obtain a substantially single-layer film in which all layers are made of the same resin composition.

[0050] Examples of coextrusion T-die molding methods include a method in which multiple resin layers are formed into a film using a multi-manifold die, and then the layers are brought into contact inside the T-die to form a multi-layered film; and a method in which multiple resins are joined and bonded together using a device that joins molten resins called a feed block, to obtain a multi-layered film.

[0051] If necessary, one or both sides of the film may be subjected to a surface treatment such as a plasma treatment, a corona treatment, an ozone treatment, a flame treatment, etc. Depending on the application of the resulting film, it is possible to select whether to perform the surface treatment on one or both sides.

[0052] <Adhesive film> The thermoplastic resin film of the present invention can be made into an adhesive film by laminating an adhesive layer on at least one surface of the film (hereinafter also referred to as "adhesive film of the present invention").

[0053] The adhesive used as the adhesive layer is not particularly limited, and various adhesives such as natural rubber resins, acrylic resins, styrene resins, silicone resins, polyvinyl ether resins, etc. may be used. In addition, a functional layer such as an adhesive layer or a thermosetting resin layer may be further provided on the adhesive layer.

[0054] In the pressure-sensitive adhesive film of the present invention, one or both sides of the film before laminating the pressure-sensitive adhesive layer may be subjected to the above-mentioned surface treatment. In addition, a primer layer may be provided between the base film and the pressure-sensitive adhesive layer, if necessary. The thickness of the adhesive layer and the primer layer can be appropriately determined according to need.

[0055] The pressure-sensitive adhesive film of the present invention uses a film having excellent expandability, and therefore can be suitably used in semiconductor manufacturing processes. EXAMPLES

[0056] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The materials used in the following examples and comparative examples and the methods for measuring the evaluated properties are as follows.

[0057] [Materials used] <Polyolefin resin> Random Polypropylene: SunAllomer Corporation's "PC630A" (random polypropylene, melt flow rate at 230°C and 2.16 kg: 7.5 g / 10 min, melting point: 135°C, tensile modulus of film alone: ​​600 MPa) Homopolypropylene: Japan Polypropylene, "FLX80H5" (homopolypropylene, melt flow rate at 230°C and 2.16 kg: 8.0 g / 10 min, melting point: 163°C, tensile modulus of film alone: ​​900 MPa) Low density polyethylene: "Novatec LC500" manufactured by Japan Polyethylene Corporation (low density polyethylene, melt flow rate at 190°C and 2.16 kg: 4.0 g / 10 min, melting point: 106°C, tensile modulus of single film: 140 MPa)

[0058] <Styrene-based elastomer> Styrene-based elastomer (A): Asahi Kasei Corporation's "Tuftec H1221" (Melt flow rate at 230°C and 2.16 kg: 4.5 g / 10 min, styrene content: 12% by mass, styrene-ethylene-butylene-styrene copolymer) Styrene-based elastomer (B): Asahi Kasei Corporation's "Tuftec H1517" (Melt flow rate at 230°C and 2.16 kg: 3.0 g / 10 min, styrene content: 43% by mass, styrene-ethylene-butylene-styrene copolymer) Styrene-based elastomer (C): Asahi Kasei Corporation's "Tuftec H1041" (Melt flow rate at 230°C and 2.16 kg: 5.0 g / 10 min, styrene content: 30% by mass, styrene-ethylene-butylene-styrene copolymer)

[0059] <Preparation of Resin Composition> The polyolefin resin and the styrene elastomer were mixed to a total of 100 parts by mass and mixed by dry blending. After visually confirming that the mixture was uniform, a resin composition for film molding was prepared for each of the surface layer, the middle layer, and the back layer.

[0060] <Film production method> The dry blended raw materials were fed into the hoppers of three Toshiba Machine single-screw extruders (surface layer: 35φmm, L / D=25mm, middle layer: 50φmm, L / D=32, back layer: 35φmm, L / D=25mm), the extruder temperature of each extruder was set to 190-240°C, and the three-layer structure of surface layer / middle layer / back layer was merged in the feed block section and extruded from a 650mm wide T-die (temperature setting 240°C, lip opening 0.5mm). The rotation speed of each extruder was set so that the thickness structure was as shown in Table 1.

[0061] The extruded molten resin was cooled and solidified on a winding machine equipped with a mirror-like cooling roll (cooling roll 700 mm wide x φ350 mm, roll temperature approximately 30°C), after which a corona treatment was performed on the surface side of the film (the surface in contact with the mirror-like cooling roll) and the film was wound up to obtain a multilayer thermoplastic resin film having a specified thickness, consisting of two types and three layers or three types and three layers. In the present invention, the surface of the obtained film that is in contact with the mirror-finished cooling roll is referred to as the surface layer.

[0062] [Thickness of each layer] The thickness of each layer was calculated from the amount of resin extruded from each extruder, and was set. Furthermore, the cross-sectional observation of the obtained film confirmed that the thickness was as set.

[0063] [Total film thickness] The thickness of the film was measured at the center and both ends using a contact thickness meter to confirm that the film had the desired thickness.

[0064] [Tensile modulus] Test pieces were taken from the obtained multilayer film using a dumbbell "SDK-600" manufactured in accordance with JIS K6732, and the tensile modulus (MPa) was measured at a tension speed of 50 mm / min using an autograph (Shimadzu Corporation AGS-X) under an atmosphere of 23°C and 50% RH, referring to JIS K7127. The tensile modulus was measured in the extrusion direction (MD) of the film and in the direction perpendicular to the extrusion direction (TD). The ratio of the tensile modulus of elasticity was calculated as MD / TD, which is the tensile modulus obtained in each of the MD and TD directions.

[0065] [Tensile elongation at break] Test pieces were taken from the obtained film using a dumbbell "SDK-600" manufactured in accordance with JIS K6732, and the tensile breaking elongation (%) was measured at a tensile speed of 300 mm / min using a small tabletop testing machine (Shimadzu EZ-L) in an atmosphere of 23°C and 50% RH. The tensile elongation at break was measured in the extrusion direction (MD) of the film.

[0066] [Recovery rate] Test pieces were taken from the obtained film using a dumbbell "SDK-600" made in accordance with JIS K6732, and measurements were performed under the following conditions using an autograph (Shimadzu Corporation AGS-X) in an atmosphere of 23°C and 50% RH. Test speed: 200mm / min Chuck distance: 40mm Tensile elongation: 50% Holding time: After 50% elongation, hold for 1 minute After the retention time had elapsed, the test piece was removed from the test machine, and the recovery rate was calculated from the test piece after 5 minutes using the following formula. TIFF2025033557000001.tif18149 The restoration rate was measured in the extrusion direction (MD) of the film.

[0067] [Crystal melting peak] Using a differential scanning calorimeter (DSC823e manufactured by Mettler Toledo), approximately 5 mg of test pieces taken from pellets of each of the polyolefin resins used were heated from 25°C to 230°C at a heating rate of 10°C / min, then cooled to 25°C at a cooling rate of 10°C / min, and then heated again to 230°C at a heating rate of 10°C / min. The crystal melting peak was calculated from the chart measured.

[0068] [Example 1] Random polypropylene and homopolypropylene were used as the resins for the front and back layers, and random polypropylene, homopolypropylene, styrene-based elastomer (A) and styrene-based elastomer (B) were used as the resins for the middle layer in the amounts shown in Table 1. A 150 μm-thick film consisting of two types and three layers was obtained by the film-forming method described above. The thicknesses of each layer were 7.5 μm for the front layer, 135 μm for the middle layer, and 7.5 μm for the back layer, and the ratio of each thickness was 5% for the front layer, 90% for the middle layer, and 5% for the back layer. The film formability was good, and the thickness did not change significantly, so that the film could be obtained. The tensile modulus of the obtained film in the MD direction was 100 MPa, in the TD direction was 90 MPa, and the tensile elongation at break was 780%, confirming that the film was flexible and suppressed defects due to breakage even when expanded. In addition, the ratio of the styrene-based elastomers (A) and (B) used was 1.4, which was within the preferred range, and the ratio of the tensile moduli (MD / TD) was 1.1, which was within the desired range of 1.0 or more and 2.0 or less. Therefore, it is presumed that the film has an excellent balance of the moduli in the MD and TD directions and can be expanded uniformly. Furthermore, the recovery rate of the film was 84%, which was confirmed to be 70% or more. This suggests that the film can be easily restored to a state close to that of the film before expansion when the expansion is interrupted and the film with the fixed wafer is recovered. Therefore, the obtained film has uniform expandability with an excellent balance of flexibility and physical properties in the MD and TD directions, and is also excellent in recovery. Since it contains a resin with a crystalline melting peak of 140°C or higher, it is presumed to be a film with good heat resistance.

[0069] [Example 2] A film was produced in the same manner as in Example 1, except that the contents of the random polypropylene, the styrene-based elastomer (A) and the styrene-based elastomer (B) as the resin for the intermediate layer were changed. The film formability was good, and the thickness did not change significantly, so that the film could be obtained. The tensile modulus of the obtained film in the MD direction was 130 MPa, that in the TD direction was 100 MPa, and the tensile elongation at break was 790%, confirming that the film was flexible and suppressed defects due to breakage even when expanded. In addition, the ratio of the styrene-based elastomers (A) and (B) used was 1.2, which was within the preferred range, and the ratio of the tensile moduli (MD / TD) was 1.3, which was within the desired range of 1.0 or more and 2.0 or less. Therefore, it is presumed that the film has an excellent balance of the moduli in the MD and TD directions and can be expanded uniformly. Furthermore, the recovery rate of the film was 81%, which was confirmed to be 70% or more. This suggests that the film can be easily restored to a state close to that of the film before expansion when the expansion is interrupted and the film with the fixed wafer is recovered. Therefore, the obtained film has uniform expandability with an excellent balance of flexibility and physical properties in the MD and TD directions, and is also excellent in recovery. Since it contains a resin with a crystalline melting peak of 140°C or higher, it is presumed to be a film with good heat resistance.

[0070] [Example 3] A film was produced in the same manner as in Example 1, except that the contents of the random polypropylene, the styrene-based elastomer (A) and the styrene-based elastomer (B) as the resin for the intermediate layer were changed. The film formability was good, and the thickness did not change significantly, so that the film could be obtained. The tensile modulus of the obtained film in the MD direction was 170 MPa, that in the TD direction was 120 MPa, and the tensile elongation at break was 790%, confirming that the film was flexible and suppressed defects due to breakage even when expanded. In addition, the ratio of the styrene-based elastomers (A) and (B) used was 1.0, which was within the preferred range, and the ratio of the tensile moduli (MD / TD) was 1.4, which was within the desired range of 1.0 or more and 2.0 or less. Therefore, it is presumed that the film has an excellent balance of the moduli in the MD and TD directions and can be expanded uniformly. Furthermore, the recovery rate of the film was 79%, which was confirmed to be 70% or more. This suggests that the film can be easily restored to a state close to that of the film before expansion when the expansion is interrupted and the film with the fixed wafer is recovered. Therefore, the obtained film has uniform expandability with an excellent balance of flexibility and physical properties in the MD and TD directions, and is also excellent in recovery. Since it contains a resin with a crystalline melting peak of 140°C or higher, it is presumed to be a film with good heat resistance.

[0071] [Example 4] A film was produced in the same manner as in Example 1, except that the contents of the random polypropylene, the styrene-based elastomer (A) and the styrene-based elastomer (B) as the resin for the intermediate layer were changed. The film formability was good, and the thickness did not change significantly, so that the film could be obtained. The tensile modulus of the obtained film in the MD direction was 230 MPa, that in the TD direction was 140 MPa, and the tensile elongation at break was 790%, confirming that the film was flexible and suppressed defects due to breakage even when expanded. In addition, the ratio of the styrene-based elastomers (A) and (B) used was 0.8, which was within the preferred range, and the ratio of the tensile moduli (MD / TD) was 1.6, which was within the desired range of 1.0 or more and 2.0 or less. Therefore, it is presumed that the film has an excellent balance of the moduli in the MD and TD directions and can be expanded uniformly. Furthermore, the recovery rate of the film was 75%, which was confirmed to be 70% or more. Therefore, it is inferred that this film can be easily restored to a state close to that of the film before expansion when the expansion is interrupted and the film with the fixed wafer is recovered. Therefore, the obtained film has uniform expandability with an excellent balance of flexibility and physical properties in the MD and TD directions, and is also excellent in recovery. Since it contains a resin with a crystalline melting peak of 140°C or higher, it is presumed to be a film with good heat resistance.

[0072] [Comparative Example 1] A film was produced in the same manner as in Example 4, except that the contents of the styrene-based elastomer (A) and the styrene-based elastomer (B) as the resin for the intermediate layer were changed. The film formability was good, and the thickness did not change significantly, so that the film could be obtained. The tensile modulus of the obtained film in the MD direction was 280 MPa, that in the TD direction was 160 MPa, and the tensile elongation at break was 790%, confirming that the film was flexible and suppressed defects due to breakage even when expanded. However, the ratio of the styrene-based elastomers (A) and (B) used was 0.6, which was outside the preferred range. As a result, the tensile modulus ratio (MD / TD) was 1.8, which was within the desired range of 1.0 to 2.0, but it was confirmed that the recovery rate of the film was below 70%. Therefore, it is presumed that the obtained film has heat resistance and an excellent balance of elastic modulus in the MD and TD directions, and that it is possible to expand the film uniformly. However, it is considered that it is difficult to easily restore the film to a state close to that of the film before expansion when the physical properties and expansion are interrupted and the film with the wafer fixed thereto is recovered.

[0073] [Comparative Example 2] A film was produced in the same manner as in Example 4, except that the contents of the styrene-based elastomer (A) and the styrene-based elastomer (B) as the resin for the intermediate layer were changed. The film formability was good, and the thickness did not change significantly, so that the film could be obtained. The tensile modulus of the obtained film in the MD direction was 320 MPa, that in the TD direction was 160 MPa, and the tensile elongation at break was 730%, confirming that the film was flexible and suppressed defects due to breakage even when expanded. However, the ratio of the styrene-based elastomers (A) and (B) used was 0.5, which was outside the preferred range of the ratio of the styrene-based elastomers. Therefore, although the ratio of the tensile moduli (MD / TD) was 2.0, which was within the desired range of 1.0 or more and 2.0 or less, it was confirmed that the recovery rate of the film was below 70%. Therefore, it is presumed that the obtained film has heat resistance and an excellent balance of elastic modulus in the MD and TD directions, and that it is possible to expand the film uniformly. However, it is considered that it is difficult to easily restore the film to a state close to that of the film before expansion when the physical properties and expansion are interrupted and the film with the wafer fixed thereto is recovered.

[0074] [Comparative Example 3] A 150μm-thick film consisting of three types and three layers was obtained by the above-mentioned film-forming method using random polypropylene as the resin for the surface layer, random polypropylene, low-density polyethylene, styrene-based elastomer (B) and styrene-based elastomer (C) as the resin for the intermediate layer, and low-density polyethylene as the resin for the back layer in the amounts shown in Table 1. The thicknesses of each layer were 7.5μm for the surface layer, 127.5μm for the intermediate layer, and 15μm for the back layer, and the ratio of each thickness was 5% for the surface layer, 85% for the intermediate layer, and 10% for the back layer. The film formability was good, and the thickness did not change significantly, so that the film could be obtained. However, the obtained film had a tensile modulus of 270 MPa in the MD direction, 120 MPa in the TD direction, and a tensile elongation at break of 680%. These results indicate that although the film has flexibility and good elongation at break, it does not contain a styrene-based elastomer (A), and the tensile modulus ratio (MD / TD) is 2.3, which is outside the desired range of 1.0 or more and 2.0 or less, and therefore the film does not have uniform expandability. Therefore, although the obtained film has excellent restorability, it is considered that the heat resistance and the balance of the elastic modulus in the MD and TD directions is poor, and the film does not have uniform expandability.

[0075] [Example 5] An acrylic adhesive (SK Dyne 1502C manufactured by Soken Chemical Industries, Ltd.) was applied onto the separator using the comma coat method so that the adhesive layer would be 25 μm thick after drying, and the adhesive layer was then dried for 5 minutes in a hot air dryer at 80°C to form an adhesive layer. The adhesive layer side of the prepared separator was bonded to the surface side of the film obtained in Example 1 after corona treatment, whereby the film of the present invention and the adhesive layer were sufficiently adhered to each other, thereby obtaining a laminated adhesive film. The obtained adhesive film has uniform expandability with an excellent balance of flexibility and physical properties in the MD and TD directions, and also has excellent recovery and heat resistance. Therefore, it is presumed that this adhesive film can be suitably used in processes in which expansion occurs after dicing, and in semiconductor manufacturing processes where heat resistance is required for processing using laser light, etc.

[0076] [Table 1]

[0077] [Industrial Applicability] The present inventors have been able to provide a film which has excellent film-forming properties when molding a resin into a film, and which has excellent heat resistance and a balance of physical properties in the MD and TD of the obtained film, has good expandability, and can be easily restored to a state close to that of the film before expansion when the expansion is interrupted and the film with the wafer fixed thereto is recovered.

Claims

1. A thermoplastic resin film comprising a polyolefin resin and a styrene elastomer as thermoplastic resins, and satisfying the following requirements: (i) The tensile modulus in both the MD and TD directions is 300 MPa or less (ii) The ratio of the tensile modulus in the MD direction to the TD direction (MD / TD) is 1.0 or more and 2.0 or less. (iii) Recovery rate in MD is 70% or more

2. The thermoplastic resin film according to claim 1, wherein the styrene-based elastomer contains a styrene-based elastomer (A) having a styrene component content of 10% by mass or more and 20% by mass or less and a styrene-based elastomer (B) having a styrene component content of 40% by mass or more and 60% by mass or less.

3. 3. The thermoplastic resin film according to claim 1, wherein the ratio (A / B) of the content of the styrene-based elastomer (A) to the content of the styrene-based elastomer (B) is within the range of 0.7 to 2.

0.

4. 3. The thermoplastic resin film according to claim 1, wherein the polyolefin resin is a polypropylene resin.

5. 5. The thermoplastic resin film according to claim 4, wherein the polypropylene-based resin contains a polypropylene-based resin having a crystalline melting peak of 140° C. or higher.

6. 6. The thermoplastic resin film according to claim 5, wherein the polypropylene-based resin having a crystalline melting peak of 140° C. or more is a homopolypropylene.

7. The thermoplastic resin film according to claim 1 or 2, which has at least three layers including a surface layer, a back layer and an intermediate layer.

8. 3. An adhesive film comprising the thermoplastic resin film according to claim 1 or 2 and an adhesive layer provided on at least one surface of the film.

9. The adhesive film for use in a semiconductor manufacturing process according to claim 8, which is used in a semiconductor manufacturing process.

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