Base material film for dicing and adhesive film for dicing

Abstract

To provide a base material film for dicing which can reduce cutting chips and whiskers generated by cutting, and has film forming property when the film is obtained and can suppress blocking of films.SOLUTION: A base material film for dicing has an ionomer resin and a layer (A) including high density polyethylene on a surface layer or a rear layer, and has tensile elastic modulus of 100 MPa or more and 500 MPa or less, tensile breaking strength of 10 MPa or more and 30 MPa or less, and tensile breaking elongation of 200% or more and 600% or less.

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic resin film that is suitable for use as a substrate for adhesive films (tapes) and the like used in a dicing process in which wafers or semiconductor wafers or packages on which circuits have been formed are cut into chips using a blade, laser, or the like, and to an adhesive film in which an adhesive layer is provided on the film. [Background technology]

[0002] BACKGROUND ART 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 traditionally been widely used as the substrate for adhesive films (tapes) used in semiconductor manufacturing processes, decorative adhesive films (tapes) such as stickers, labels, and marking films attached to signs, automobiles, etc. to add design features, and decorative sheets.

[0003] The PVC film itself has rigidity, but a plasticizer is added to impart flexibility so that it can function as an adhesive film. However, depending on the plasticizer used, there are problems such as poor compatibility with the adhesive, poor stability when used as an adhesive film, and significant bleeding out of the plasticizer. In addition, there is a tendency for regulations on the use of plasticizers themselves to be strengthened. Therefore, polyolefin resin films have come to be widely used as an alternative 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 problems described above, polyolefin resin films are increasingly being used (e.g., Patent Document 1).

[0005] In recent years, semiconductor elements have become smaller and thinner, and the effects of chips from the cut substrate and whisker-like residues (hereinafter referred to as whiskers) that grow from the cut parts of the film generated during the dicing process of cutting semiconductor wafers, packages, etc. have become greater, sometimes resulting in lower yields and reduced quality. While the generation of chips and whiskers is influenced by the dicing conditions, it would be desirable to be able to provide a base film that suppresses the generation of chips and whiskers regardless of the cutting conditions.

[0006] Patent Document 2 discloses a film that uses an ionomer resin as a resin that can reduce cutting waste during dicing, and that has excellent expandability even in the expansion step after dicing.

[0007] However, in the film described in Patent Document 2, only an ionomer is used as the resin used in the surface layer, which is considered to be an improvement in terms of film formability when obtaining the film and suppression of problems caused by blocking between films after the obtained film is wound up. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 09-008111 [Patent Document 2] Japanese Patent Publication No. 2023-155246 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0009] In view of the above problems, the present invention aims to provide a substrate film for dicing that can reduce cutting waste and whiskers generated by cutting the substrate in a dicing process in which a wafer or a semiconductor wafer or package having a circuit formed thereon is cut into chips using a blade, laser, or the like to separate the wafer into individual pieces, and that has excellent film-forming properties when obtaining a film. Another object of the present invention is to provide a pressure-sensitive adhesive film for dicing that is suitable for use in a dicing step by providing a pressure-sensitive adhesive layer on the substrate film for dicing. [Means for solving the problem]

[0010] The present inventors have conducted extensive research into a dicing substrate film that uses a specific resin composition for each layer, thereby achieving excellent film-forming properties, film handling properties, and flexibility, as well as reducing the generation of cutting chips and whiskers, and have completed the present invention.

[0011] That is, the gist of the present invention is as follows. [1] A dicing substrate film having a layer (A) containing an ionomer resin and high-density polyethylene as a surface or backing layer, and having a tensile modulus of elasticity of 100 MPa or more and 500 MPa or less, a tensile breaking strength of 10 MPa or more and 30 MPa or less, and a tensile breaking elongation of 200% or more and 600% or less. [2] The dicing substrate film according to [1], which has a three-layer structure of a surface layer / an intermediate layer / a back layer. [3] The substrate film for dicing according to [1] or [2], wherein the intermediate layer contains an ionomer resin and low-density polyethylene. [4] The substrate film for dicing according to any one of [1] to [3], wherein layer (B) constituting the surface opposite to layer (A) contains a high-density polyethylene resin and a low-density polyethylene resin. [5] The substrate film for dicing according to any one of [1] to [4], wherein the thickness of the layer (A) is 1 to 30 μm. [6] An adhesive film for dicing, comprising an adhesive layer provided on the surface of layer (A) of the base film for dicing according to any one of [1] to [5]. [Effects of the Invention]

[0012] By using the film described in the present invention, it is possible to reduce cutting waste and whiskers generated by cutting the substrate in the dicing process in which a wafer or a semiconductor wafer or package on which a circuit is formed is cut into chips using a blade, laser, or the like, and to provide a substrate film for dicing that has excellent film-forming properties when obtaining a film. Furthermore, by providing a pressure-sensitive adhesive layer on the dicing substrate film of the present invention, it is possible to produce a pressure-sensitive adhesive film for dicing that is suitable for use in the dicing process. Furthermore, it is expected that the film can be used not only in the dicing process but also as a film for semiconductor manufacturing processes such as back-grinding, if necessary. DETAILED DESCRIPTION OF THE INVENTION

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

[0014] The film of the present invention has a layer (A) containing an ionomer resin and high-density polyethylene as a front or back layer, and has a tensile modulus of elasticity of 100 MPa or more and 500 MPa or less, a tensile strength at break of 10 MPa or more and 30 MPa or less, and a tensile elongation at break of 200% or more and 600% or less. The resins constituting the film of the present invention will be described in detail below.

[0015] <Ionomer resin> The film of the present invention is a film having a layer (A) containing an ionomer resin and high-density polyethylene as a front or back layer. By incorporating an ionomer resin and high-density polyethylene into the surface layer or back layer, it is possible to reduce the amount of cutting chips and whiskers generated by cutting the substrate during the dicing process, improve film formability when obtaining a film, and prevent blocking between films when the film is wound into a roll. In particular, by incorporating an ionomer resin, it becomes easier to prevent the generation of cutting chips and whiskers.

[0016] The ionomer resin is not particularly limited, and known ionomer resins can be used. Examples of known ionomer resins include a resin in which a binary copolymer of ethylene and (meth)acrylic acid is crosslinked with a metal ion, and a resin in which a ternary copolymer of ethylene, (meth)acrylic acid, and a (meth)acrylic acid ester is crosslinked with a metal ion. Examples of metal ions used in the ionomer resin include potassium ions, sodium ions, magnesium ions, and zinc ions.

[0017] The density of ionomer resin is 0.910 to 0.980 g / cm 3 It is preferable that the density is in the range of 0.910 to 0.980 g / cm 3 By using an ionomer resin in this range, film formability when obtaining a film can be improved, and the flexibility of the obtained film can also be improved. 3 The density is preferably in the range of 0.930 to 0.960, and more preferably in the range of 0.930 to 0.960. Methods for measuring the density include Method A (underwater displacement method), Method B (pycnometer method), Method C (float-sink method), and Method D (density gradient tube method) described in "JIS K 7112." There are no particular restrictions on the measurement method, and an appropriate method can be selected and used.

[0018] The ionomer resin preferably has a crystalline melting peak of 80°C or higher. Having a crystalline melting peak of 80°C or higher is preferable because it does not impair the heat resistance of the resulting thermoplastic resin film. The peak is more preferably 83°C or higher, and even more preferably 86°C or higher. The crystalline melting peak can be measured using a differential scanning calorimeter according to JIS K 7122.

[0019] Regarding the strength of the ionomer resin, the tensile modulus of a film obtained from the ionomer resin alone is preferably in the range of 50 to 500. If the tensile modulus is in the range of 50 to 500 MPa, it is possible to maintain appropriate strength and impart flexibility to the film of the present invention. It is more preferably in the range of 60 to 400 MPa, and even more preferably in the range of 70 to 300 MPa. The tensile modulus can be measured according to the method described in "JIS K 7127." Appropriate conditions can be selected for use during measurement, such as the shape of the test piece, the test speed, and the distance between chucks. Regarding the elongation of the ionomer resin, it is preferable that the tensile breaking elongation of a film obtained from the ionomer resin alone is 600% or less. If the tensile breaking elongation is 600% or less, it is possible to reduce cutting chips and whiskers generated when cutting the film. It is more preferably 550% or less, and even more preferably 500% or less. The tensile breaking elongation can be measured by the same method as the method for measuring the strength described above.

[0020] The melt flow rate of the ionomer resin is selected appropriately depending on the molding method and application, but preferably is 0.1 to 50 g / 10 min as measured at a temperature of 190°C under a load of 2.16 kg. A melt flow rate of 0.1 g / 10 min or higher provides good film formability, while a melt flow rate of 50 g / 10 min or lower enables the film thickness precision to be maintained at a high level. A melt flow rate of 0.5 to 40 g / 10 min is more preferable, and a melt flow rate of 1.0 to 30 g / 10 min is even more preferable. Examples of methods for measuring the melt flow rate include those described in "JIS K 7210." The measurement conditions, such as temperature and load, can be selected appropriately depending on the material used and its properties.

[0021] Commercially available ionomer resins include "Himilan" manufactured by Mitsui Dow Polychemicals. A single grade of Himilan may be used, or two or more grades may be used in combination. The grade can be selected as needed, taking into consideration factors such as film-forming properties, heat resistance and flexibility of the resulting film, and blocking between films.

[0022] <High-density polyethylene> The film of the present invention is a film having a layer (A) containing an ionomer resin and high-density polyethylene as a front or back layer. By including an ionomer resin and high-density polyethylene in the surface or back layer, it is possible to reduce cutting chips and whiskers generated by cutting the substrate during the dicing process, and it is also possible to suppress film formability when obtaining a film and blocking between films when the film is wound into a roll. In particular, by including high-density polyethylene, it is possible to improve the hardness of the surface or back layer of the film and improve the blocking between films. Furthermore, the inclusion of high-density polyethylene makes it easy to reduce the adhesion between the transport roll and the surface or back layer during film formation, thereby improving film formability when obtaining a film.

[0023] There are no particular limitations on the high-density polyethylene used in the present invention, and any common high-density polyethylene may be used, including a high-density polyethylene composed of an ethylene homopolymer and a copolymer of ethylene as the main component and another monomer copolymerizable with ethylene (hereinafter referred to as another monomer). Examples of other monomers include α-olefins having 3 or more carbon atoms. Examples of α-olefins having 3 or more carbon atoms include propylene, 1-butene, isobutene, 1-pentene, 2-methyl-butene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-pentene, 1-octene, 1-decene, and 1-dodecene. From the viewpoints of availability of the monomer and the performance of the resulting high-density polyethylene, α-olefins having 3 or more carbon atoms are preferably in the range of 3 to 20.

[0024] The density of high density polyethylene is 0.940 to 0.970 g / cm 3 It is preferable that the density is in the range of 0.940 to 0.970 g / cm 3 By using a high-density polyethylene within this range, it becomes easy to adjust the elastic modulus of the surface layer and / or back layer and intermediate layer of the obtained thermoplastic resin film. It is more preferably 0.942 to 0.968 g / cm 3 The density is preferably in the range of 0.944 to 0.966, and more preferably in the range of 0.944 to 0.966. Methods for measuring the density include Method A (underwater displacement method), Method B (pycnometer method), Method C (float-sink method), and Method D (density gradient tube method) described in "JIS K 7112." There are no particular restrictions on the measurement method, and an appropriate method can be selected and used.

[0025] The high-density polyethylene preferably has a crystalline melting peak of 120°C or higher. Having a crystalline melting peak of 120°C or higher makes it possible to impart sufficient heat resistance to the resulting thermoplastic resin film. The peak is more preferably 125°C or higher, and even more preferably 130°C or higher. The crystalline melting peak can be measured using a differential scanning calorimeter according to JIS K 7122.

[0026] Regarding the strength of the high-density polyethylene, the tensile modulus of a film obtained from high-density polyethylene alone is preferably in the range of 600 to 1800 MPa. If the tensile modulus is in the range of 600 to 1800 MPa, it is possible to impart appropriate strength and flexibility to the thermoplastic resin film of the present invention, and it is possible to improve the blocking properties of the obtained film. It is more preferably in the range of 650 to 1750 MPa, and even more preferably in the range of 700 to 1700 MPa. The tensile modulus can be measured according to the method described in "JIS K 7127." Appropriate conditions such as the shape of the test piece, the test speed, and the distance between chucks during measurement can be selected and used.

[0027] The melt flow rate of high-density polyethylene is selected appropriately depending on the molding method and application, but preferably is 0.1 to 50 g / 10 min as measured at a temperature of 190°C under a load of 2.16 kg. A melt flow rate of 0.1 g / 10 min or higher provides good film formability, while a melt flow rate of 50 g / 10 min or lower ensures good film thickness accuracy. A melt flow rate of 0.5 to 40 g / 10 min is more preferred, and 1.0 to 30 g / 10 min is even more preferred. Examples of methods for measuring the melt flow rate include those described in "JIS K 7210." Measurement conditions such as temperature and load can be selected appropriately depending on the material used and its properties.

[0028] Commercially available high-density polyethylenes include, for example, Novatec HD "HJ360," Novatec HD "HJ491," Novatec HD "HF560," and Novatec HD "HY350" (all manufactured by Japan Polyethylene Corporation), Santech HD "B161," Santech HD "J340," and Santech HD "J241" (all manufactured by Asahi Kasei Corporation), Nipolon Hard "4000," Nipolon Hard "2000," Nipolon Hard "2500," and Nipolon Hard "LW13D" (all manufactured by Tosoh Corporation). These high-density polyethylenes may be used alone or in combination of two or more. They can be appropriately selected as needed, taking into consideration the film-forming properties when obtaining a thermoplastic resin film, the heat resistance and flexibility of the resulting film, and blocking between films.

[0029] <Other resins> Resins other than ionomer resins and high-density polyethylene can be added as needed to the film of the present invention, as long as they do not affect heat resistance, flexibility, film-forming properties, blocking properties, or the suppression of chipping and whisker formation. Examples of other resins include polypropylene-based resins such as random polypropylene and homopolypropylene, polyethylene-based resins such as low-density polyethylene resin (LDPE) and linear low-density polyethylene (LLDPE), thermoplastic elastomers such as olefin-based elastomers and styrene-based elastomers, cyclic olefin-based resins, and polymethylpentene-based resins. Among these, polyethylene-based resins are preferred because of their compatibility with ionomer resins and high-density polyethylene and their ease of adjusting heat resistance and flexibility.

[0030] Examples of polyethylene resins include ethylene homopolymers, copolymers of ethylene, primarily composed of ethylene, with other monomers copolymerizable with ethylene (low-density polyethylene (LDPE), high-pressure low-density polyethylene, linear low-density polyethylene (LLDPE), ethylene copolymers obtained by polymerization using a metallocene catalyst (metallocene polyethylene), ethylene-vinyl acetate copolymers, ethylene-methyl (meth)acrylate copolymers, ethylene-ethyl (meth)acrylate copolymers, and ethylene-butyl (meth)acrylate copolymers. Among these, it is preferable to use 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 heat resistance and flexibility of the resulting film.

[0031] The density of low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) is 0.900 to 0.940 g / cm 3 It is preferable that the density is in the range of 0.900 to 0.940 g / cm 3 By using a material in this range, it is easy to adjust the heat resistance and flexibility of the resulting thermoplastic resin film. More preferably, it is 0.902 to 0.938 g / cm 3 The density is preferably in the range of 0.904 to 0.936, and more preferably in the range of 0.904 to 0.936. The density can be measured by the same method as described in the section on high-density polyethylene.

[0032] The crystalline melting peak of low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) preferably exhibits a temperature of 70°C or higher. Having a crystalline melting peak of 70°C or higher makes it easy to adjust the heat resistance of the resulting thermoplastic resin film. The temperature is more preferably 75°C or higher, and even more preferably 80°C or higher. The crystalline melting peak can be measured using the same method as described in the section on high-density polyethylene.

[0033] Regarding the strength of low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE), the tensile modulus of a film obtained from these resins alone is preferably within the range of 30 to 400 MPa. If the tensile modulus is within the range of 30 to 400 MPa, it becomes easy to adjust the flexibility of the thermoplastic resin film of the present invention. It is more preferably within the range of 40 to 350 MPa, and even more preferably within the range of 50 to 300 MPa. The tensile modulus can be measured using the same method as described in the section on high-density polyethylene.

[0034] Commercially available low-density polyethylene (LDPE) products include, for example, Novatec LD "LC500," Novatec LD "LC520," and Novatec LD "LC720" (all manufactured by Japan Polyethylene Co., Ltd.), as well as F224N, F324C, and F522N (all manufactured by Ube Maruzen Polyethylene Co., Ltd.). Commercially available linear low-density polyethylene (LLDPE) products include, for example, Novatec LL "UF420" and Novatec LL "UF641" (both manufactured by Japan Polyethylene Co., Ltd.), Yumerit "0540F" and Yumerit "4040F" (both manufactured by Ube Maruzen Polyethylene Co., Ltd.).

[0035] 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.

[0036] The polymethylpentene resin is preferably a homopolymer containing methylpentene as a monomer or a copolymer with other monomers, such as a copolymer of α-olefins and 4-methylpentene-1, which are listed as examples of other monomers copolymerizable with propylene for polypropylene resins. When the polymethylpentene resin is a copolymer, the content of the α-olefin component used in the copolymerization is preferably 20% by mass or less. By setting the content to 20% by mass or less, it is possible to suppress a decrease in the crystalline melting peak. It is more preferably 10% by mass or less. Examples of polypropylene-based resins include homopolypropylene, which is a homopolymer of propylene; random polypropylene, which is a copolymer containing propylene as the main component and other monomers copolymerizable with propylene; and block polypropylene, which is typified by a block copolymer of ethylene and propylene. Examples of thermoplastic elastomers include olefin-based elastomers, styrene-based elastomers, acrylic-based elastomers, vinyl chloride-based elastomers, urethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, fluorine-based elastomers, silicone-based elastomers, etc. Among these, it is preferable to select from olefin-based elastomers and / or styrene-based elastomers from the viewpoints of compatibility with ionomer resins and high-density polyethylene, heat resistance, and ease of adjusting flexibility.

[0037] <Other ingredients> The film of the present invention may contain various additives to impart antistatic properties, heat resistance, weather resistance, and the like. 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, nucleating agents, ultraviolet absorbers, bulking agents, inorganic fillers that impart rigidity, and elastomers other than those described above that impart flexibility, within the scope of not impairing the effects of the present invention.

[0038] Known polymer antistatic agents can be used, such as block copolymers of a hydrophobic block and a hydrophilic block, in which the hydrophobic block and the hydrophilic block form a block copolymer via ester bonds, ether bonds, amide bonds, imide bonds, urethane bonds, urea bonds, etc.

[0039] As the ultraviolet absorber, known ones can be used, and examples thereof include benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, and triazine-based ultraviolet absorbers.

[0040] As the light stabilizer, known ones can be used, and examples thereof include hindered amine light stabilizers.

[0041] As the lubricant or antiblocking agent, it is preferable to use a silicone-olefin copolymer, since it has excellent compatibility with the above-mentioned polypropylene-based resins, polyethylene-based resins, etc., and can prevent defects caused by bleed-out onto the surface of the resulting film and can impart long-term scratch resistance and slip properties.

[0042] <Dicing substrate film> The film of the present invention is a film having a layer (A) containing an ionomer resin and high-density polyethylene as a front or back layer. By incorporating ionomer resin and high-density polyethylene into the surface or back layer, it is possible to reduce the amount of cutting debris and whiskers generated by cutting the substrate during the dicing process, making the film suitable for use in the dicing process, which is one of the semiconductor manufacturing processes. Furthermore, in order to suppress the generation of cutting chips and whiskers, as well as to improve film formability and prevent film-to-film blocking when wound into a roll, it is preferable to not only incorporate an ionomer resin and high-density polyethylene but also to have a three-layer structure consisting of a surface layer, an intermediate layer, and a back layer. The three-layer structure allows layer (A) to be provided on the surface that comes into contact with the blade or laser during the dicing process, making it possible to produce a film that easily suppresses the generation of cutting chips and whiskers. Layer (A) must be present in either the front or back layer, but both the front and back layers may be layer (A). When both layers are layer (A), they may be made of resins having the same composition, or they may be made of resins having different compositions. When both layers are layer (A), the layer can be selected appropriately taking into consideration the desired film performance, film-forming properties when obtaining a film, and blocking properties.

[0043] The content of the ionomer resin in Layer (A) is preferably 15 to 95% by mass based on 100% by mass of the resin constituting Layer (A). By setting the content within the range of 15 to 95% by mass, it becomes possible to adjust the tensile elongation at break of the obtained film within a desired range. The content is more preferably 20 to 93% by mass, and even more preferably 25 to 91% by mass. The content of high-density polyethylene in Layer (A) is preferably 5 to 75% by mass based on 100% by mass of the resin constituting Layer (A). By setting the content within this range, the film can be easily peeled from the transport roll during film production, and the resulting film can have good anti-blocking properties. The content is more preferably 7 to 65% by mass, and even more preferably 9 to 55% by mass.

[0044] Other resins may be added to Layer (A) as long as they do not impair film-forming properties or blocking properties and do not affect the reduction of cutting chips or whiskers. The amount of other resins added is preferably 0 to 80% by mass, more preferably 0 to 75% by mass, and even more preferably 0 to 70% by mass, based on 100% by mass of the resin constituting Layer (A).

[0045] The thickness of layer (A) in the film is preferably within the range of 1 to 30 μm. A thickness of 1 to 30 μm facilitates the suppression of the generation of cutting chips and whiskers, and is therefore preferred because it does not impair the flexibility of the resulting film. A thickness of 3 to 27 μm is more preferred, and a thickness of 5 to 24 μm is even more preferred. Furthermore, when it is anticipated that the film will be cut to a greater depth using a blade or laser, and a desired film thickness is required, the thickness of layer (A) can be set to 30 μm or more. In such cases, the thickness of layer (A) can be appropriately selected and determined taking into account the depth of cutting. It is also possible to control layer (A) as a percentage of the total film thickness rather than its thickness. When controlling as a percentage of the total thickness, the proportion of layer (A) when the total thickness is taken as 100% is preferably within the range of 1 to 40%. A more preferred range is 3 to 35%, and even more preferred is 5 to 30%.

[0046] It is preferable that the surface or back layer is layer (A), and that the layer opposite layer (A) contains high-density polyethylene and low-density polyethylene. The inclusion of high-density polyethylene makes it possible to improve the blocking properties between films, while the inclusion of low-density polyethylene is preferable because it makes it possible to impart flexibility without impairing blocking properties. The content of high-density polyethylene and low-density polyethylene used in the layer opposite Layer (A) is preferably 20 to 80% by mass of high-density polyethylene relative to 100% by mass of the resin constituting the opposite layer. It is more preferably 30 to 70% by mass, and even more preferably 40 to 60% by mass. The content of low-density polyethylene is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, and even more preferably 40 to 60% by mass. Resins other than high-density polyethylene and low-density polyethylene can also be added to the extent that they do not affect the performance of the film. The amount of other resins added is preferably 0 to 50% by mass, more preferably 0 to 40% by mass, and even more preferably 0 to 30% by mass. The thickness of the layer (A) and the layer on the opposite side may be the same or different, and can be appropriately selected and determined taking into consideration the properties of the resulting film and the film-forming properties when obtaining the film.

[0047] The intermediate layer in a three-layer structure is not particularly limited, and can be appropriately selected from ionomer resins, high-density polyethylene, and other resins described in the section on other resins. From the viewpoint of interlayer adhesion between the intermediate layer and the front or back layer, it is preferable to incorporate an ionomer resin and high-density polyethylene. The intermediate layer may also be layer (A). When the intermediate layer is layer (A), it may have the same composition as the front or back layer, or a different composition. Furthermore, in order to ensure adhesion between the resulting dicing substrate film and the front or back layer, and to anticipate the blade or laser reaching the intermediate layer and the need to suppress the generation of cutting chips and whiskers, it is preferable to add an ionomer resin to the intermediate layer. It is more preferable to incorporate low-density polyethylene to impart flexibility to the film. The composition of the intermediate layer preferably contains 10 to 50% by mass of ionomer resin, 5 to 50% by mass of high-density polyethylene, and 0 to 85% by mass of low-density polyethylene and / or other resins relative to 100% by mass of the resin constituting the intermediate layer; more preferably contains 10 to 30% by mass of ionomer resin, 5 to 40% by mass of high-density polyethylene, and 0 to 85% by mass (preferably 30 to 85%) of low-density polyethylene and / or other resins relative to 100% by mass of the resin constituting the intermediate layer; and particularly preferably contains 10 to 25% by mass of ionomer resin, 5 to 30% by mass of high-density polyethylene, and 0 to 85% by mass (preferably 45 to 85%) of low-density polyethylene and / or other resins relative to 100% by mass of the resin constituting the intermediate layer. By keeping the ionomer resin and high-density polyethylene, low-density polyethylene and / or other resins in the intermediate layer within the above ranges, it is possible to obtain a film with good handleability without excessively reducing the breaking elongation of the film, and this is preferable because it makes it easier to maintain the adhesion between the intermediate layer and the front and back layers, the flexibility of the obtained film, and the effect of suppressing cutting chips and whiskers. The intermediate layer may also be composed of two or more layers. In this case, a film configuration consisting of three or more layers is also included. In this case, all layers of the intermediate layer consisting of two or more layers may have the same composition or different compositions. From the viewpoint of film productivity and economic efficiency, a three-layer film consisting of a front layer, a back layer, and one intermediate layer is preferred. In this case, whether to use a two-kind three-layer film in which the front and back layers are made of the same resin composition or a three-kind three-layer film in which the front and back layers are made of different resin compositions can be selected appropriately as needed, taking into consideration the required performance and use of each of the front and back layers of the film, and processability when providing a pressure-sensitive adhesive layer, which will be described later.

[0048] The total thickness of the dicing substrate film of the present invention is preferably 30 to 250 μm. If it is 30 μm or more, the film production properties and the handleability of the resulting film are good when producing the film, and good flexibility can be maintained. If it is 250 μm or less, the handleability and processability of the film in the step of laminating a pressure-sensitive adhesive layer onto the film can be maintained good. The total thickness of the dicing substrate film of the present invention is more preferably 40 to 230 μm, and even more preferably 50 to 210 μm.

[0049] The tensile modulus of the dicing substrate film of the present invention must be in the range of 100 MPa or more and 500 MPa or less. If it is 100 MPa or more, the film is not too flexible and can maintain good handleability, and if it is 500 MPa or less, the flexibility of the film is not impaired and the film can maintain good handleability and processability in the step of laminating a pressure-sensitive adhesive layer thereon. It is more preferably in the range of 110 MPa or more and 450 MPa or less, and even more preferably in the range of 120 MPa or more and 400 MPa or less.

[0050] The tensile breaking strength of the dicing substrate film of the present invention must be 10 MPa or more and 30 MPa or less. If the tensile breaking strength is 10 MPa or more, the film will not easily break even in the process of laminating a pressure-sensitive adhesive layer to the film, making it possible to maintain good handleability and processability. If the tensile breaking strength is 30 MPa or less, it is possible to prevent whiskers that occur when the film is cut from breaking easily and remaining on the film or semiconductor wafer. The tensile breaking strength is more preferably in the range of 11 MPa or more and 29 MPa or less, and even more preferably in the range of 12 MPa or more and 28 MPa or less. The tensile elongation at break of the dicing substrate film of the present invention must be 200% or more and 600 MPa or less. If it is 200% or more, the film will not easily break even in the process of laminating a pressure-sensitive adhesive layer to the film, making it possible to maintain good handleability and processability. If it is 600% or less, it will be possible to prevent whiskers that occur when the film is cut from extending too long and remaining on the film or semiconductor wafer. More preferably, it is in the range of 210% or more and 590% or less, and even more preferably, it is in the range of 220% or more and 580% or less. The tensile modulus and elongation at break can be measured using the same methods as those described in the section on ionomer resins.

[0051] Although known methods can be used to form the film of the present invention, melt extrusion molding is preferred. Among melt extrusion molding methods, T-die molding is more preferred, in which a molten resin is extruded from an extruder having a T-die and cooled and solidified to obtain a film. 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, which can be the film of the present invention consisting of a surface layer, a back layer, and an intermediate layer. It is also possible to obtain an intermediate layer consisting of two or more layers.

[0052] Examples of co-extrusion 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 within the T-die to form a multi-layered film; and a method in which multiple resins are brought into contact with each other using a device that combines molten resins called a feed block, and then the resins are brought into contact with each other to form a multi-layered film.

[0053] The resin extruded in a molten state from a T-die can be cooled and solidified by contacting it with a chill roll set at a predetermined temperature. The chill roll temperature setting is not particularly limited, but it is preferably set to 80°C or lower. A temperature of 80°C or lower can prevent the molten resin from adhering to the chill roll and becoming unable to be peeled off. It is more preferably set to 70°C or lower, and even more preferably set to 60°C or lower. Furthermore, the surface temperature of the chill roll is preferably set to 100°C or lower, from the viewpoint of preventing similar problems caused by film sticking. When using a molding method using a nip with a rubber roll or metal roll, as described below, it is preferable to adjust the temperature setting and surface temperature of these rolls to be similar to that of the chill roll. The method for adhering the film to the cooling roll is not particularly limited, and examples thereof include an air knife, an air chamber, electrostatic pinning, and a nip between a rubber roll or a metal roll. When using a nip molding method using rubber or metal rolls, the appearance and surface roughness of the resulting film will vary depending on the surface shape of the rolls used, so it is possible to adjust the surface roughness (Ra) and maximum height (Rz) of the rubber or metal roll appropriately depending on the appearance and surface roughness required for the film. Among the above-mentioned molding methods, from the viewpoint of adjusting the surface roughness (Ra) and maximum height (Rz) and film productivity, it is more preferable to use a molding method using an air knife or an air chamber, or a molding method using a nip with a touch roll, a rubber roll, or a metal roll.

[0054] If necessary, one or both sides of the film may be subjected to a surface treatment such as plasma treatment, corona treatment, ozone treatment, flame treatment, etc. Depending on the intended use of the resulting film and the prevention of blocking between films, it is possible to select whether to perform a surface treatment on one or both sides, or whether to perform no corona treatment on either side.

[0055] <Adhesive film> The substrate film for dicing of the present invention can be made into an adhesive film for dicing by providing an adhesive layer on at least one of the front and back surfaces (hereinafter also referred to as "adhesive film of the present invention"). The adhesive used in 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. Furthermore, a functional layer such as an adhesive layer or a thermosetting resin layer may be further provided on the adhesive layer.

[0056] The pressure-sensitive adhesive layer can be provided by directly coating the pressure-sensitive adhesive onto the thermoplastic resin film of the present invention, or by laminating the pressure-sensitive adhesive layer onto a separator or the like having a release layer, and then attaching the pressure-sensitive adhesive layer side of the separator to the surface layer of the film of the present invention, thereby transferring the pressure-sensitive adhesive layer. In the pressure-sensitive adhesive film of the present invention, one or both surfaces of the film may be subjected to the above-mentioned surface treatment before the pressure-sensitive adhesive layer is provided. Furthermore, a primer layer may be provided between the film and the pressure-sensitive adhesive layer, if necessary. The thickness of the adhesive layer and the primer layer can be appropriately determined as needed.

[0057] By using the film of the present invention, it is possible to reduce cutting waste and whiskers generated by cutting the substrate in the dicing process in which a wafer or a semiconductor wafer or package on which a circuit is formed is cut into chips using a blade, laser, or the like, and to provide a substrate film for dicing that has good film formability when obtaining a film and that can suppress blocking between films. Furthermore, by providing a pressure-sensitive adhesive layer on the dicing substrate film of the present invention, it is possible to produce a pressure-sensitive adhesive film for dicing that is suitable for use in the dicing process. Furthermore, it is expected that the film can be used not only in the dicing process but also as a film for semiconductor manufacturing processes such as back-grinding, if necessary. [Example]

[0058] The present invention will be specifically explained below by showing 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.

[0059] [Materials used] The thermoplastic resins used to form the respective layers were high density polyethylene, low density polyethylene, ionomer resin, and masterbatch of antioxidant, as shown below.

[0060] <High-density polyethylene> "HF560" manufactured by Japan Polyethylene Corporation (high-density polyethylene, melt flow rate at 190°C and 2.16 kg: 7.0 g / 10 min, crystalline melting peak: 134°C, density: 0.963 g / cm 3 , Tensile modulus of the film alone: ​​1000 MPa) <Low-density polyethylene> Japan Polyethylene Corporation, "LC500" (low-density polyethylene, melt flow rate at 190°C and 2.16 kg: 4.0 g / 10 min, crystalline melting peak: 106°C, density: 0.923 g / cm 3 , Tensile modulus of the film alone: ​​140 MPa)

[0061] <Ionomer resin> Mitsui Dow Polychemicals, "Himilan 1705" (ionomer resin, melt flow rate at 190°C and 2.16 kg: 5.0 g / 10 min, crystalline melting peak: 91°C, density: 0.950 g / cm 3 , Tensile modulus of the film alone: ​​290 MPa)

[0062] <Antioxidant masterbatch> Novatec LL LXAO (film masterbatch containing 5% by mass of antioxidant), manufactured by Japan Polyethylene Corporation

[0063] <Preparation of Resin Composition> The above thermoplastic resins were blended to a total of 100 parts by mass. When using a masterbatch of antioxidant, 3 parts of the masterbatch of antioxidant were added, and blending was carried out to a total of 103 parts by mass. When using two or more types of thermoplastic resins, they were mixed by dry blending, and it was confirmed by visual inspection that they were uniformly mixed.

[0064] <Film production method> Each resin composition was charged into the hopper 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), and the extruder temperature of each extruder was set to 190-230°C. The three-layer structure of surface layer / middle layer / back layer was merged in the feed block section and extruded through a 650mm wide T-die (temperature setting 210-230°C, lip opening 0.5mm). The rotation speed of each extruder was set to obtain the thickness structure shown in Table 1. The extruded molten resin was nipped between a mirror-finished metal cooling roll (700 mm wide x φ350 mm, surface roughness Ra approximately 0.1 μm) and a matte rubber roll (700 mm wide x φ200 mm, surface roughness Ra approximately 1.0 μm) through which cooling water set at approximately 30°C was passed. After cooling and solidifying into a film, the film was taken up on a winding machine to obtain two-type, three-layer and three-type, three-layer films with a thickness of approximately 80 μm. In the present invention, the surface of the obtained film facing the metal cooling roll is referred to as the surface layer.

[0065] [Thickness of each layer] The thickness of each layer was calculated from the amount of resin extruded from each extruder. [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. [Film forming property] When a film was obtained by the above-mentioned film production method, the adhesion of the film to the metal cooling roll was evaluated according to the following criteria. ◎: No sticking and easy to transport 〇: Slight sticking is observed, but it can be easily transported △: Sticking is observed, but it is possible to peel it off from the roll and transport it. ×: Significant sticking occurs, and transport is difficult due to problems such as wrapping around the roll.

[0066] Tensile modulus Test pieces were taken from the obtained 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 the following conditions, which refer to JIS K7127: 23°C, 50% RH. The tensile modulus was measured in the extrusion direction (MD) of the film.

[0067] [Tensile strength] Test pieces were taken from the obtained film using a dumbbell "SDK-600" manufactured in accordance with JIS K6732, and the tensile breaking strength (MPa) was measured at a tension 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 breaking strength was measured in the extrusion direction (MD) of the film.

[0068] [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 elongation at break (%) was measured at a tension 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.

[0069] [Example 1] The resin compositions for the surface, intermediate and back layers were prepared by mixing high density polyethylene, low density polyethylene and ionomer resin in the amounts shown in Table 1. Using the resin compositions for the surface, middle, and back layers, a three-layer, three-type film with a total thickness of 80 μm was obtained by nip molding using the mirror-finished metal cooling roll and matte rubber roll described above. The film-forming conditions were adjusted so that the thickness of each layer was 16 μm for the surface layer, 60 μm for the middle layer, and 4 μm for the back layer. This film was prone to sticking to the metal cooling roll because it contained 90% by mass of ionomer resin in the surface layer. However, because it contained 10% by mass of high-density polyethylene, although sticking was observed, it was possible to peel it off and transport it without any problems, so it was determined that it was possible to produce a film. Furthermore, no blocking was observed between the wound films. This film exhibited a tensile modulus of 230 MPa, confirming that it has sufficient flexibility and handleability for use in semiconductor manufacturing processes such as dicing. The film consisting of the above-mentioned surface layer, middle layer, and back layer has a tensile breaking strength of 16 MPa and a tensile breaking elongation of 350%.Since it has moderate breaking strength and breaking elongation, it does not easily break when produced or handled, and when cut, it generates little cutting debris, which is thought to prevent long whiskers from growing and remaining on the film or semiconductor wafer. Therefore, it was confirmed that this film has sufficient film-forming properties when obtained as a film, is excellent in flexibility and handling when used in semiconductor manufacturing processes such as dicing, and is capable of suppressing the generation of debris and whisker residue when cut.

[0070] [Example 2] The same procedure as in Example 1 was carried out except that the high-density polyethylene and ionomer resin in the surface layer were used in the amounts shown in Table 1. The resulting film was a three-layer film with a total thickness of 80 μm. The film-forming conditions were adjusted so that the thickness of each layer was 16 μm for the surface layer, 60 μm for the middle layer, and 4 μm for the back layer. Although slight sticking to the metal cooling roll was observed due to the film containing 85% by mass of ionomer resin in the surface layer, there was no problem with peeling and the film could be easily transported due to the 15% by mass of high-density polyethylene content. Furthermore, no blocking was observed between the wound films. This film exhibited a tensile modulus of 240 MPa, confirming that it has sufficient flexibility and handleability for use in semiconductor manufacturing processes such as dicing. The film consisting of the above-mentioned surface layer, middle layer, and back layer has a tensile breaking strength of 17 MPa and a tensile breaking elongation of 380%.Since it has moderate breaking strength and breaking elongation, it does not easily break when produced or handled, and when cut, it generates little cutting debris, which is thought to prevent long whiskers from growing and remaining on the film or semiconductor wafer. Therefore, it was confirmed that this film has excellent film-forming properties when obtained as a film, is flexible and easy to handle when used in semiconductor manufacturing processes such as dicing, and is capable of suppressing the generation of debris and whisker residue when cut.

[0071] [Example 3] The same procedure as in Example 1 was carried out except that the high-density polyethylene and ionomer resin in the surface layer were used in the amounts shown in Table 1. The resulting film was a three-layer film with a total thickness of 80 μm. The film-forming conditions were adjusted so that the thickness of each layer was 16 μm for the surface layer, 60 μm for the middle layer, and 4 μm for the back layer. Although this film contains 72% by mass of ionomer resin in the surface layer, it also contains 28% by mass of high-density polyethylene, so it did not stick to the metal cooling roll and could be easily transported. Furthermore, no blocking was observed between the wound films. This film exhibited a tensile modulus of 270 MPa, confirming that it has sufficient flexibility and handleability for use in semiconductor manufacturing processes such as dicing. The film consisting of the above-mentioned surface layer, middle layer, and back layer has a tensile breaking strength of 18 MPa and a tensile breaking elongation of 410%.Since it has moderate breaking strength and breaking elongation, it does not easily break when produced or handled, and when cut, it generates little cutting debris, which is thought to prevent long whiskers from growing and remaining on the film or semiconductor wafer. Therefore, it was confirmed that this film has excellent film-forming properties when obtained as a film, is flexible and easy to handle when used in semiconductor manufacturing processes such as dicing, and is capable of suppressing the generation of debris and whisker residue when cut.

[0072] [Example 4] The same procedure as in Example 3 was carried out except that the thicknesses of the surface layer and the intermediate layer were changed. The resulting film was a three-layer film with a total thickness of 80 μm. The film-forming conditions were adjusted so that the thickness of each layer was 20 μm for the surface layer, 56 μm for the middle layer, and 4 μm for the back layer. Although this film contains 72% by mass of ionomer resin in the surface layer, it also contains 28% by mass of high-density polyethylene, so it did not stick to the metal cooling roll and could be easily transported. Furthermore, no blocking was observed between the wound films. This film exhibited a tensile modulus of 250 MPa, confirming that it has sufficient flexibility and handleability for use in semiconductor manufacturing processes such as dicing. The film consisting of the above-mentioned surface layer, middle layer, and back layer has a tensile breaking strength of 20 MPa and a tensile breaking elongation of 430%.Since it has moderate breaking strength and breaking elongation, it does not easily break when produced or handled, and when cut, it generates little cutting debris, which is thought to prevent long whiskers from growing and remaining on the film or semiconductor wafer. Therefore, it was confirmed that this film has excellent film-forming properties when obtained as a film, is flexible and easy to handle when used in semiconductor manufacturing processes such as dicing, and is capable of suppressing the generation of debris and whisker residue when cut.

[0073] [Example 5] The same procedure as in Example 3 was carried out except that the thicknesses of the surface layer and the intermediate layer were changed. The resulting film was a three-layer film with a total thickness of 80 μm. The film-forming conditions were adjusted so that the thickness of each layer was 4 μm for the surface layer, 72 μm for the middle layer, and 4 μm for the back layer. Although this film contains 72% by mass of ionomer resin in the surface layer, it also contains 28% by mass of high-density polyethylene, so it did not stick to the metal cooling roll and could be easily transported. Furthermore, no blocking was observed between the wound films. This film exhibited a tensile modulus of 210 MPa, confirming that it has sufficient flexibility and handleability for use in semiconductor manufacturing processes such as dicing. The film consisting of the above-mentioned surface layer, middle layer, and back layer has a tensile breaking strength of 19 MPa and a tensile breaking elongation of 460%.Since it has moderate breaking strength and breaking elongation, it does not easily break when produced or handled, and when cut, it generates little cutting debris, which is thought to prevent long whiskers from growing and remaining on the film or semiconductor wafer. Therefore, it was confirmed that this film has excellent film-forming properties when obtained as a film, is flexible and easy to handle when used in semiconductor manufacturing processes such as dicing, and is capable of suppressing the generation of debris and whisker residue when cut.

[0074] [Example 6] The same procedure as in Example 1 was carried out except that the thermoplastic resins used in the surface layer were high-density polyethylene, low-density polyethylene, and ionomer resin in the amounts shown in Table 1. The resulting film was a three-layer film with a total thickness of 80 μm. The film-forming conditions were adjusted so that the thickness of each layer was 16 μm for the surface layer, 60 μm for the middle layer, and 4 μm for the back layer. This film contained only 55% by mass of ionomer resin in the surface layer and 10% by mass of high-density polyethylene, so it did not stick to the metal cooling roll and could be easily transported. Furthermore, no blocking was observed between the wound films. This film exhibited a tensile modulus of 200 MPa, confirming that it has sufficient flexibility and handleability for use in semiconductor manufacturing processes such as dicing. The film consisting of the above-mentioned surface layer, middle layer, and back layer has a tensile breaking strength of 19 MPa and a tensile breaking elongation of 440%.Since it has moderate breaking strength and breaking elongation, it does not easily break when produced or handled, and when cut, it generates little cutting debris, which is thought to prevent long whiskers from growing and remaining on the film or semiconductor wafer. Therefore, it was confirmed that this film has excellent film-forming properties when obtained as a film, is flexible and easy to handle when used in semiconductor manufacturing processes such as dicing, and is capable of suppressing the generation of debris and whisker residue when cut.

[0075] [Example 7] The same procedure as in Example 3 was carried out except that the high-density polyethylene, low-density polyethylene, and ionomer resin in the intermediate layer were blended in the amounts shown in Table 1. The resulting film was a three-layer film with a total thickness of 80 μm. The film-forming conditions were adjusted so that the thickness of each layer was 16 μm for the surface layer, 60 μm for the middle layer, and 4 μm for the back layer. Although this film contains 72% by mass of ionomer resin in the surface layer, it also contains 28% by mass of high-density polyethylene, so it did not stick to the metal cooling roll and could be easily transported. Furthermore, no blocking was observed between the wound films. This film exhibited a tensile modulus of 290 MPa, confirming that it has sufficient flexibility and handleability for use in semiconductor manufacturing processes such as dicing. The film consisting of the above-mentioned surface layer, middle layer, and back layer has a tensile breaking strength of 19 MPa and a tensile breaking elongation of 430%.Since it has moderate breaking strength and breaking elongation, it does not easily break when produced or handled, and when cut, it generates little cutting debris, which is thought to prevent long whiskers from growing and remaining on the film or semiconductor wafer. Therefore, it was confirmed that this film has excellent film-forming properties when obtained as a film, is flexible and easy to handle when used in semiconductor manufacturing processes such as dicing, and is capable of suppressing the generation of debris and whisker residue when cut.

[0076] [Example 8] The blending amounts and thicknesses of the front and back layers described in Example 3 were reversed, and an antioxidant masterbatch was blended into each layer as shown in Table 1. Other than that, the same procedures as in Example 3 were carried out. This film was produced assuming that the back layer would be diced with a laser, blade, or the like. The resulting film was a three-layer film with a total thickness of 80 μm. The film-forming conditions were adjusted so that the thickness of each layer was 4 μm for the surface layer, 60 μm for the middle layer, and 16 μm for the back layer. Because this film does not contain ionomer resin in the surface layer, it did not stick to the metal cooling roll and could be easily transported. Furthermore, no blocking was observed between the wound films. This film exhibited a tensile modulus of 280 MPa, confirming that it has sufficient flexibility and handleability for use in semiconductor manufacturing processes such as dicing. The film consisting of the above-mentioned surface layer, middle layer, and back layer has a tensile breaking strength of 18 MPa and a tensile breaking elongation of 420%.Since it has moderate breaking strength and breaking elongation, it does not easily break when produced or handled, and when cut, it generates little cutting debris, which is thought to prevent long whiskers from growing and remaining on the film or semiconductor wafer. Therefore, it was confirmed that this film has excellent film-forming properties when obtained as a film, is flexible and easy to handle when used in semiconductor manufacturing processes such as dicing, and is capable of suppressing the generation of debris and whisker residue when cut.

[0077] [Example 9] The same procedure as in Example 6 was carried out except that the thermoplastic resin used in the surface layer was high-density polyethylene, low-density polyethylene, and ionomer resin in adjusted amounts. The resulting film was a three-layer film with a total thickness of 80 μm. The film-forming conditions were adjusted so that the thickness of each layer was 16 μm for the surface layer, 60 μm for the middle layer, and 4 μm for the back layer. This film contained only 20% by mass of ionomer resin in the surface layer and 10% by mass of high-density polyethylene, so it did not stick to the metal cooling roll and could be easily transported. Furthermore, no blocking was observed between the wound films. This film exhibited a tensile modulus of 190 MPa, confirming that it has sufficient flexibility and handleability for use in semiconductor manufacturing processes such as dicing. The film consisting of the above-mentioned surface layer, middle layer, and back layer has a tensile breaking strength of 21 MPa and a tensile breaking elongation of 520%.Since it has moderate breaking strength and breaking elongation, it does not easily break when produced or handled, and when cut, it generates little cutting debris, which is thought to prevent long whiskers from growing and remaining on the film or semiconductor wafer. Therefore, it was confirmed that this film has excellent film-forming properties when obtained as a film, is flexible and easy to handle when used in semiconductor manufacturing processes such as dicing, and is capable of suppressing the generation of debris and whisker residue when cut.

[0078] [Comparative Example 1] The same procedure as in Example 1 was carried out, except that the thermoplastic resin used in the surface layer was only an ionomer resin. The surface layer of this film was composed only of ionomer resin, and it was found to stick significantly to the metal cooling roll. It was difficult to peel off, and problems with wrapping around the metal cooling roll were also observed, confirming that the film was extremely poor in terms of film-forming properties.

[0079] Comparative Example 2 The same procedures as in Example 1 were carried out except that the thermoplastic resins used were only high-density polyethylene and low-density polyethylene in the amounts shown in Table 1, and no ionomer resin was used. The resulting film was a two-type, three-layer film with a total thickness of 80 μm. The film-forming conditions were adjusted so that the thickness of each layer was 4 μm for the surface layer, 72 μm for the middle layer, and 4 μm for the back layer. This film does not contain ionomer resin in the surface layer, but contains high-density polyethylene, so it did not stick to the metal cooling roll and could be easily transported. Furthermore, no blocking was observed between the wound films. This film exhibited a tensile modulus of 150 MPa, confirming that it has sufficient flexibility and handleability for use in semiconductor manufacturing processes such as dicing. However, although the tensile breaking strength was 21 MPa, the tensile breaking elongation was 700%, which suggests that the whiskers that are generated when cutting grow long and remain on the film or semiconductor wafer. Therefore, although this film has excellent film-forming properties when obtained as a film and is thought to have excellent flexibility and ease of handling when used in semiconductor manufacturing processes such as dicing, it is highly likely that whisker residue will remain when cut, and it is presumed that this film is not suitable for semiconductor manufacturing processes including dicing.

[0080] [Table 1]

[0081] [Example 10] An acrylic adhesive (SK Dyne 1502C manufactured by Soken Chemical & Engineering Co., Ltd.) was applied onto the separator using the comma coating 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 the adhesive layer. The adhesive layer side of the prepared separator was then subjected to corona treatment and bonded to the surface of the film obtained in Example 1, thereby achieving sufficient adhesion between the film of the present invention and the adhesive layer, and obtaining a laminated adhesive film. Since an adhesive film was obtained that is highly flexible and easy to handle, and that can suppress the generation of debris and residual whiskers when cut, it is presumed that an adhesive film has been obtained that can be suitably used in semiconductor manufacturing processes that include a dicing process.

[0082] [Industrial Applicability] According to the present invention, in the dicing process in which a wafer or a semiconductor wafer or package having a circuit formed thereon is cut into chips using a blade, a laser, or the like to separate the wafer into individual chips, it is possible to reduce the cutting waste and whiskers generated by cutting the substrate, and it is also possible to provide a substrate film for dicing that has good film formability when obtaining a film and that can suppress blocking between films. Furthermore, by providing a pressure-sensitive adhesive layer on the dicing substrate film of the present invention, it is possible to produce a pressure-sensitive adhesive film for dicing that is suitable for use in the dicing process. Furthermore, it is expected that the film can be used not only in the dicing process but also as a film for semiconductor manufacturing processes such as back-grinding, if necessary.

Claims

1. A dicing substrate film having a layer (A) containing an ionomer resin and high-density polyethylene as a surface layer or a back layer, and having a tensile modulus of elasticity of 100 MPa or more and 500 MPa or less, a tensile breaking strength of 10 MPa or more and 30 MPa or less, and a tensile breaking elongation of 200% or more and 600% or less.

2. The substrate film for dicing according to claim 1 , which has a three-layer structure of a surface layer, an intermediate layer and a back layer.

3. The dicing substrate film according to claim 2 , wherein the intermediate layer contains an ionomer resin and a low-density polyethylene.

4. The substrate film for dicing according to claim 2 , wherein the layer constituting the surface opposite to the layer (A) contains a high-density polyethylene resin and a low-density polyethylene resin.

5. The dicing substrate film according to claim 2, wherein the thickness of the layer (A) is 1 to 30 μm.

6. A pressure-sensitive adhesive film for dicing, comprising a pressure-sensitive adhesive layer provided on the surface of layer (A) of the substrate film for dicing according to any one of claims 1 to 5.

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