Base film for semiconductor manufacturing tape

Abstract

To provide a base film for a semiconductor manufacturing tape, which can reduce environmental load and has excellent uniform elongation, rigidity, and stress relaxation properties.SOLUTION: A base film 1 for a semiconductor manufacturing tape has a functional layer 2 and a surface layer 3 that is provided on at least one side of the functional layer 2. The functional layer 2 contains a homopolymer of 1-butene, a copolymer of pentene, and an olefin-based elastomer. A content of the olefin-based elastomer relative to a total of the functional layer 2 is 10 mass% or more to 40 mass% or less. At least one of the functional layer 2 and the surface layer 3 contains a plant-derived olefin-based resin. The biomass level in the entire base film 1 is 4 mass% or more and less than 49 mass%.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a substrate film for a tape for manufacturing semiconductors (hereinafter, sometimes simply referred to as "substrate film"). [Background technology]

[0002] As a method for manufacturing semiconductor devices such as IC chips, for example, a method is widely used in which a wafer circuit formed on a substantially disk-shaped semiconductor wafer is divided by dicing on a semiconductor manufacturing tape (dicing tape) for wafers to obtain individual semiconductor devices. After dicing, for example, the dicing tape is stretched to form gaps between the semiconductor devices (i.e., expanded), and then each semiconductor device is picked up by a robot or the like.

[0003] In addition, a dicing die attach film (DDAF), in which an adhesive layer is laminated on the adhesive layer of the above-mentioned dicing tape, is used as a semiconductor manufacturing tape for wafers. After the wafer circuits are divided by dicing on the dicing die attach film, the dicing die attach film is stretched to form gaps between the semiconductor devices, and then the adhesive layer is photocured. The semiconductor devices are then peeled off from the adhesive layer with the adhesive layer still attached and picked up.

[0004] In recent years, there has been an increasing need to reduce the amount of carbon dioxide emitted in order to reduce the environmental impact and combat global warming, and substrate films for semiconductor manufacturing tapes that contain plant-derived (biomass-derived) materials have been proposed.

[0005] For example, a substrate film has been proposed that contains a chlorine-containing resin such as polyvinyl chloride resin, a resin containing succinic acid and 1,4-butanediol, which are plant-derived components, as copolymer components, and an epoxy group-containing resin (see, for example, Patent Document 1).

[0006] In order to reduce the environmental impact, a substrate film using a polyolefin resin instead of the vinyl chloride resin has been proposed. For example, a random copolymer of propylene and ethylene and / or an α-olefin having 4 to 8 carbon atoms, in which the content of ethylene and / or an α-olefin having 4 to 8 carbon atoms is 6% by weight or more and the density measured according to ASTM D1505 is 885 kg / m 3 A substrate film has been proposed that is composed of a laminate of an intermediate layer containing the following propylene-based random copolymer (β) as a main component, and surface layers laminated on both sides of the intermediate layer and containing a propylene-based random copolymer (α) as a main component, the surface layer having a lower content of ethylene and / or an α-olefin having 4 to 8 carbon atoms and a higher density than the propylene-based random copolymer (β) (for example, see Patent Document 2). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2011-61189 A [Patent Document 2] JP 2018-65327 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, while the substrate film described in Patent Document 1 above is capable of reducing the environmental impact, it uses a chlorine-containing resin such as polyvinyl chloride resin, which causes chloride ions to migrate to the semiconductor wafer and contaminate the semiconductor element. This poses a problem.

[0009] In addition, the base film described in Patent Document 2 has stress relaxation properties that can replace vinyl chloride resin, but because a semi-crystalline resin is used instead of an amorphous resin, necking occurs when the base film is stretched to form gaps between semiconductor devices, and the uniform stretchability of the base film is insufficient. In addition, because the base film has poor rigidity, there is a problem that the unwinding of the base and tape formation, including the application of an adhesive, are unstable in the manufacturing process of the base film.

[0010] Therefore, the present invention has been made in consideration of the above problems, and aims to provide a base film for semiconductor manufacturing tape that can reduce the environmental impact and has excellent uniform elongation, rigidity, and stress relaxation properties. [Means for solving the problem]

[0011] In order to achieve the above-mentioned object, the base film for semiconductor manufacturing tape of the present invention is a base film for semiconductor manufacturing tape having a functional layer and a surface layer provided on at least one side of the functional layer, wherein the functional layer contains a 1-butene homopolymer, a pentene copolymer, and an olefin-based elastomer, the content of the olefin-based elastomer in the entire functional layer is 10% by mass or more and 40% by mass or less, at least one of the functional layer and the surface layer contains an olefin-based resin derived from plants, and the biomass content in the entire base film for semiconductor manufacturing tape is 4% by mass or more and less than 49% by mass. Effect of the Invention

[0012] According to the present invention, it is possible to provide a substrate film for a tape for manufacturing a semiconductor device, which is capable of reducing the environmental load and has excellent uniform elongation, rigidity, and stress relaxation properties. [Brief description of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view showing a substrate film for a semiconductor manufacturing tape according to an embodiment of the present invention. [Diagram 2]1 is an SS curve (stress-strain curve) for the base film of Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The substrate film for semiconductor manufacturing tape of the present invention will be specifically described below. Note that the present invention is not limited to the following embodiments, and can be appropriately modified and applied within the scope of the present invention.

[0015] The substrate film of the present invention is a substrate film constituted by a laminate of a functional layer (intermediate layer) and a surface layer provided on at least one side of the functional layer.

[0016] An example of a substrate film having this multilayer structure is a substrate film 1 having a three-layer structure composed of a laminate of a functional layer 2 and a surface layer 3 laminated on both sides of the functional layer 2, laminated in the order of surface layer / functional layer / surface layer, as shown in Figure 1.

[0017] The functional layer may include a homopolymer of 1-butene, a copolymer of pentene, and an olefin-based elastomer.

[0018] <1-butene homopolymer> In the present invention, a homopolymer obtained by polymerizing 1-butene alone is used as the polybutene. This 1-butene homopolymer has a high molecular weight and bulky side chains, and the strong intermolecular forces due to these bulky side chains can improve the uniform stretchability of the base film, in the same way as in the case of amorphous polymers, despite being a crystalline polymer.

[0019] The 1-butene homopolymer used in the present invention may have a weight average molecular weight (Mw) of about 500,000 to 1,500,000.

[0020] The "weight average molecular weight" refers to that calculated in accordance with JIS K 7252-1:2016.

[0021] Furthermore, since the 1-butene homopolymer used in the present invention has a high molecular weight, it has low surface adhesion and is more rigid than amorphous polyolefins. Therefore, in the production process of the base film, it is possible to provide a base film having high rigidity that allows the base film to be unwound and made into a tape, including coating with an adhesive.

[0022] As described above, by using a homopolymer of 1-butene as the resin forming the base film, the uniform extensibility and rigidity of the base film can be improved.

[0023] In addition, from the viewpoint of improving uniform elongation and rigidity, the content of 1-butene homopolymer in the entire functional layer 2 is preferably 30% by mass or more and 85% by mass or less, and more preferably 30% by mass or more and 60% by mass or less, of 100% by mass of the functional layer.

[0024] <Pentene copolymer> In the base film 1 of the present invention, the functional layer 2 contains a pentene copolymer as polypentene from the viewpoint of improving the stress relaxation property that enables the dimensions of the semiconductor manufacturing tape to be maintained after expansion. The use of such a pentene copolymer improves the stress relaxation property of the base film 1, making it possible to hold the semiconductor manufacturing tape with a grip ring and to maintain the spacing between each semiconductor device (semiconductor chip).

[0025] The pentene copolymer is not particularly limited, but is preferably a copolymer of 4-methyl-1-pentene and an α-olefin, which has a glass transition temperature near room temperature, is excellent in stress relaxation properties, and has good flexibility due to the α-olefin as a copolymer component. Examples of the copolymer include "Absortomer (registered trademark) EP-1013" (a product name) manufactured by Mitsui Chemicals, Inc., which is a copolymer of 4-methyl-1-pentene and polypropylene, and "Absortomer (registered trademark) EP-1001" (a product name) manufactured by Mitsui Chemicals, Inc.

[0026] In addition, when a copolymer of 4-methyl-1-pentene and polypropylene is used, from the viewpoint of improving flexibility and stress relaxation properties, the content of polypropylene in the entire copolymer of 4-methyl-1-pentene and polypropylene is preferably 10 mol % or more and 30 mol % or less, based on 100 mol % of the copolymer of 4-methyl-1-pentene and polypropylene.

[0027] From the viewpoint of improving stress relaxation properties, the content of the pentene copolymer in the entire functional layer 2 is preferably 10% by mass or more and 40% by mass or less, with the functional layer being 100% by mass.

[0028] <Olefin elastomer> In addition, in the base film 1 of the present invention, the functional layer 2 contains an olefin-based elastomer. The olefin-based elastomer is composed of an olefin-based material that conforms to the definition of the term elastomer in JIS K 6200. More specifically, a material composed of a copolymer of amorphous or low crystalline α-olefin corresponds to the olefin-based elastomer, one mainly made of polyethylene is called an ethylene-based elastomer, and one mainly made of polypropylene is called a propylene-based elastomer. For example, an example of an ethylene-based elastomer is the product name "Tafmer (registered trademark)" manufactured by Mitsui Chemicals, and an example of a propylene-based elastomer is the product name "Vistamax (registered trademark)" manufactured by ExxonMobil.

[0029] When a propylene-based elastomer is used, the content of polyethylene in the entire propylene-based elastomer is preferably 9% or more and 30% or less, based on 100% of the propylene-based elastomer, from the viewpoint of improving flexibility.

[0030] By using such an olefin-based elastomer, the crystallinity is reduced and the occurrence of a yield point can be suppressed, thereby improving the uniform extensibility of the base film.

[0031] From the viewpoint of improving uniform stretchability, the content of the olefin-based elastomer in the entire functional layer 2 is 10% by mass or more and 40% by mass or less, with the functional layer being 100% by mass. If the content of the olefin-based elastomer is 40% by mass or more, the olefin-based elastomer component with low crystallinity becomes excessive, which may reduce rigidity and make it difficult to unwind the substrate and form it into a tape, including applying an adhesive.

[0032] The content of the olefin-based elastomer in the entire functional layer 2 is preferably 20% by mass or more and 30% by mass or less, based on 100% by mass of the functional layer.

[0033] From the viewpoint of further improving uniform elongation, the density of the olefin-based elastomer is 0.850 to 0.900 g / cm 3 It is preferable that the density is 0.860 to 0.890 g / cm 3 It is more preferable that:

[0034] Next, a description will be given of the surface layer 3 in the base film 1 of the present invention. Examples of the surface layer 3 include those containing the above-mentioned 1-butene homopolymer, or polyolefin resins such as polyethylene and polypropylene.

[0035] Despite its high molecular weight, 1-butene homopolymer can be molded using a general-purpose extruder. Since the high molecular weight components give the film low surface adhesion, when used in a surface layer, it can suppress adhesion to the transport roll when the base film is transported, as well as suppress blocking when the base film is wound up and draw resonance when the base film is molded, thereby improving the processing stability of the base film.

[0036] In addition, examples of polypropylene include homopolymers and copolymers of polypropylene. Among these, the homopolymer of polypropylene is homopolypropylene obtained by polymerizing propylene alone, and this homopolymer of polypropylene has high stereoregularity and a high degree of crystallinity that contributes to the melting point, and therefore has excellent heat resistance. In addition, since the degree of crystallinity is high, the rigidity is high, but by mixing with linear low-density polyethylene, flexibility that contributes to the expandability of the base film can be obtained.

[0037] <Low density polyethylene> The surface layer 3 is made of a polyolefin resin having a density of 0.860 g / cm 3 More than 0.93g / cm 3 It is preferred that the polyethylene comprises low density polyethylene (LDPE) having a density of 0.860 g / cm or less. 3 More than 0.93g / cm 3 The low-density polyethylene described below has low surface adhesion, and therefore, when used in a surface layer, can suppress adhesion to the transport roll when the base film is transported and can suppress blocking when the base film is wound up, thereby improving the processing stability of the base film.

[0038] Furthermore, among low-density polyethylenes, linear low-density polyethylene (LLDPE) has side-chain branches in the linear structure of high-density polyethylene, so compared to high-density polyethylene, its crystallinity is not too high and it has excellent flexibility.

[0039] From the viewpoint of strength, linear low-density polyethylene produced using a metallocene catalyst or a Ziegler catalyst may also be used.

[0040] The melt mass flow rate (MFR) of the linear low density polyethylene is preferably 0.5 to 7.5 g / 10 min, more preferably 1.0 to 6.0 g / 10 min, and even more preferably 2.0 to 5.0 g / 10 min. When the melt mass flow rate (MFR) is 0.5 g / 10 min or more, the molecular weight is not too large, and flexibility and processability can be improved, and when it is 7.5 g / 10 min or less, the molecular weight is not too small, and processing stability can be improved.

[0041] The melt mass flow rate is obtained by measurement in accordance with the standard of JIS K7210:1999.

[0042] From the viewpoint of improving uniform extensibility and rigidity, the content of linear low-density polyethylene in the entire surface layer 2 is preferably 12% by mass or more and 70% by mass or less, based on 100% by mass of the surface layer.

[0043] From the above, the density is 0.93g / cm 3 By using a low density polyethylene having a density of 100 or less, the flexibility and isotropy of the base film can be improved.

[0044] In addition, from the viewpoint of improving uniform elongation and rigidity, the content of 1-butene homopolymer in the surface layer 3 (i.e., each of the surface layers 3 laminated on both sides of the functional layer 2) is preferably more than 0 mass% and not more than 30 mass% of 100 mass% of the surface layer.

[0045] <Plant-derived olefin resin> In the base film 1 of the present invention, from the viewpoint of reducing the environmental load, at least one of the functional layer 2 and the surface layer 3 contains a plant-derived (biomass-derived) olefin resin.

[0046] Examples of plant-derived olefin resins that can be used include plant-derived low-density polyethylene (LDPE), plant-derived linear low-density polyethylene (LLDPE), and plant-derived high-density polyethylene (HDPE).

[0047] The plant-derived low-density polyethylene is a biomass polyethylene that is a polymer of monomers containing ethylene derived from biomass, and an example of such a low-density polyethylene is sugar cane-derived low-density polyethylene.

[0048] In the base film of the present invention, a low-density polyethylene having a biomass content of 95% or more is used.

[0049] The "biomass content" referred to here is specifically the percentage of radioactive carbon ( 14 It is a value measured based on the principle of radiocarbon dating by determining the concentration of carbon dioxide (C).

[0050] In the substrate film of the present invention, the biomass degree of the entire substrate film is 4% by mass or more and less than 49% by mass, based on 100% by mass of the substrate film. If the biomass degree is less than 4% by mass, the reduction in environmental load will be insufficient, and if the biomass degree is 49% by mass or more, the olefin resin derived from biomass, which has a low crystallinity, will be excessive, resulting in a decrease in rigidity and making it difficult to unwind the substrate and form it into a tape, including coating with an adhesive.

[0051] That is, if the biomass ratio relative to the entire base film is within the above range, it is possible to sufficiently reduce the environmental load and to sufficiently improve the rigidity of the base film.

[0052] The biomass ratio in the entire base film is preferably from 7.5% by mass to 45% by mass, and more preferably from 10% by mass to 40% by mass.

[0053] Furthermore, in the base film of the present invention, when the functional layer 2 contains a plant-derived olefin-based resin, the content of the plant-derived olefin-based resin in the entire functional layer 2 is not particularly limited as long as the biomass degree in the entire base film is the above-mentioned 4 mass% or more and less than 49 mass%, but can be, for example, 5 mass% or more and 45 mass% or less of 100 mass% of the functional layer.

[0054] Similarly, in the base film of the present invention, when the surface layer 3 contains a plant-derived olefin-based resin, the content of the plant-derived olefin-based resin in the entire surface layer 3 is not particularly limited as long as the biomass degree in the entire base film is the above-mentioned 4 mass% or more and less than 49 mass%, but can be, for example, 10 mass% or more and 90 mass% or less of the 100 mass% surface layer.

[0055] From the viewpoint of improving processing stability and reducing the environmental impact, the content of low-density polyethylene in the entire surface layer 2 (i.e., the total content of the above-mentioned low-density polyethylene and the plant-derived low-density polyethylene) is preferably 70% by mass or more and 100% by mass or less, based on 100% by mass of the surface layer.

[0056] In addition, when using plant-derived low-density polyethylene, the density is 0.930 g / cm 3 It is preferred that the polyethylene contains a plant-derived low-density polyethylene having a density of 0.930 g / cm or less. 3 In the following cases, the degree of crystallinity is not too high and flexibility is excellent.

[0057] In order to improve processing stability, the density of plant-derived low-density polyethylene is 0.860 g / cm 3 It is preferable that the content is 0.870 g / cm or more. 3 More preferably, it is equal to or greater than this.

[0058] The melt mass flow rate (MFR) of the plant-derived low-density polyethylene is preferably 0.5 to 7.5 g / 10 min, more preferably 1.0 to 6.0 g / 10 min, and even more preferably 2.0 to 5.0 g / 10 min. When the melt mass flow rate (MFR) is 0.5 to 7.5 g / 10 min, processing stability can be improved.

[0059] The above melt mass flow rate can be obtained by measurement in accordance with the standard of ASTM D1238.

[0060] <Base film> In the substrate film 1 of the present invention, the stress (at 20% elongation) in the mechanical axis (longitudinal) direction (hereinafter referred to as "MD") of the substrate film and the direction perpendicular thereto (hereinafter referred to as "TD") is preferably 7.0 MPa to 20 MPa, more preferably 7.5 MPa to 15 MPa, and even more preferably 8 MPa to 13 MPa. If the stress is greater than 20 MPa, the rigidity becomes too large, so that the pick-up ability of the semiconductor device decreases and the semiconductor device may be damaged, whereas if the stress is less than 7.0 MPa, the rigidity becomes low, so that in the manufacturing process of the substrate film, it becomes difficult to unwind the substrate and to form it into a tape, including coating with an adhesive.

[0061] In other words, when the stress (at 20% elongation) in MD and TD is 7.0 MPa or more and 20 MPa or less, a substrate film having excellent rigidity that can be made into a tape, including unwinding the substrate and coating with an adhesive, can be provided in the substrate film manufacturing process.

[0062] Furthermore, in the case of conventional base films containing polyolefins, no necking occurs when the base film is stretched by 20%, allowing uniform expansion. However, once the base film is stretched by 40%, necking begins to occur, making uniform expansion difficult.

[0063] Therefore, from the viewpoint of improving the uniform extensibility of the base film, in the base film 1 of the present invention, the ratio of the stress (at 40% elongation) to the stress (at 20% elongation) in the MD and TD (i.e., the elongation percentage of the base film) is preferably from 0.95 to 2. If the elongation percentage of the base film is greater than 2, the expansion ring may become difficult to hold due to an excessive increase in stress, and if the elongation percentage of the base film is less than 0.95, necking may occur, making uniform expansion difficult.

[0064] That is, if the elongation percentage of the base film is 0.95 or more and 2 or less, necking does not occur and uniform expansion becomes possible.

[0065] The elongation percentage of the base film is more preferably 1 or more and 1.80 or less, and from the viewpoint of preventing necking and ensuring uniform expansion, the elongation percentage of the base film is even more preferably 1.05 or more and 1.70 or less.

[0066] In the base film 1 of the present invention, from the viewpoint of further improving the uniform extensibility of the base film, the ratio of stress (at 5% elongation) to stress (at 40% elongation) is preferably 1.05 or less in MD and TD. If the ratio of stress (at 5% elongation) to stress (at 40% elongation) is 1.05 or less, the occurrence of the later-described yield point (the yield point during the elongation rate from 0% to 100% under the condition of a tensile speed of 300 mm / min) can be suppressed, thereby suppressing the occurrence of necking and enabling uniform expansion.

[0067] It is more preferable that the ratio of the stress (at 5% elongation) to the stress (at 40% elongation) is 0.40 or more and 1.05 or less, and from the viewpoint of preventing the occurrence of necking and ensuring uniform expansion, it is even more preferable that the ratio of the stress (at 5% elongation) to the stress (at 40% elongation) is 0.60 or more and less than 0.90.

[0068] In addition, the base film 1 of the present invention preferably has a stress relaxation rate of 25% or more, more preferably 30% or more, and even more preferably 35% or more. If the stress relaxation rate is less than 25%, the stress absorption performance is poor, and it may become difficult to maintain the dimensions of the tape for semiconductor production.

[0069] That is, when the stress relaxation rate is 25% or more, the dimensions of the tape for semiconductor production can be maintained, and a substrate film for a tape for semiconductor production having excellent stress relaxation properties can be provided.

[0070] The "stress relaxation rate" referred to here can be determined by the method described in the Examples section below.

[0071] In addition, from the viewpoint of suppressing the occurrence of sagging due to the isotropy of the base film during expansion, the ratio of the stress in MD (at 20% elongation) to the stress in TD (at 20% elongation) (i.e., the stress ratio of the base film at 20% elongation) is preferably 0.80 or more and 1.30 or less, more preferably 0.85 or more and 1.25 or less, and even more preferably 0.90 or more and 1.20 or less.

[0072] The thickness of the base film 1 of the present invention is preferably 50 to 300 μm, and more preferably 80 to 150 μm. If the thickness of the base film is 50 μm or more, the handleability is improved, and if the thickness is 300 μm or less, the flexibility (expandability) can be improved. In the case of a base film for a wafer, the thickness of the base film is preferably 50 to 150 μm, and more preferably 70 to 110 μm.

[0073] For example, in the case of a substrate film having a three-layer structure in which a surface layer / functional layer / surface layer are laminated in this order, the thickness of the surface layer is not particularly limited, but is preferably 2 to 60 μm, more preferably 4 to 40 μm, and the thickness of the functional layer is not particularly limited, but is preferably 40 to 120 μm, more preferably 50 to 80 μm.

[0074] For example, in the case of a base film having a three-layer structure in which surface layer / functional layer / surface layer are laminated in that order, from the viewpoints of processability and low cost, the ratio of the functional layer to the entire base film is preferably 40 to 95%, and more preferably 50 to 90%.

[0075] <Manufacturing method> For example, when producing a base film 1 having a three-layer structure in which a surface layer / functional layer / surface layer are laminated in this order as shown in Figure 1, first, a resin material for forming the surface layer and a resin material for forming the functional layer are prepared.

[0076] Next, a three-kind, three-layer co-extruder equipped with a T-die is used to simultaneously extrude and mold the resin material for forming the surface layer and the resin material for forming the functional layer at a predetermined temperature to produce the base film 1 having the multilayer structure of the present invention, which is composed of a laminate of the functional layer 2 and the surface layers 3 laminated on both sides of the functional layer 2. The base film of the present invention may also be produced by a known calendar method or inflation method.

[0077] <Other forms> The substrate film 1 of the present invention may contain various additives. As the additives, known additives that are usually used in semiconductor manufacturing tapes can be used, such as crosslinking assistants, antistatic agents, heat stabilizers, antioxidants, ultraviolet absorbers, lubricants, antiblocking agents, colorants, crystal nucleating agents, processing assistants, etc. These additives may be used alone or in combination of two or more.

[0078] Furthermore, examples of the crosslinking aid include triallyl isocyanurate. When the base film contains a crosslinking aid, the content of the crosslinking aid in the base film is preferably 0.05 to 5 parts by mass, and more preferably 1 to 3 parts by mass, relative to 100 parts by mass of the resin forming the base film.

[0079] In addition, the above description has been given using as an example a substrate film having a three-layer structure in which surface layer / functional layer / surface layer is laminated in that order; however, the substrate film having a multilayer structure of the present invention is not limited to a three-layer structure as long as it has the above-mentioned functional layer, and may be, for example, a substrate film having a five-layer structure in which surface layer / functional layer / functional layer / functional layer / surface layer is laminated in that order.

[0080] In addition, in the above-mentioned embodiment, a substrate film 1 having a three-layer structure in which surface layer / functional layer / surface layer are laminated in this order has been described as an example, but the substrate film of the present invention may also be a substrate film having a single-layer structure consisting of only the above-mentioned functional layer 2.

[0081] In this case, first, a resin material for forming the functional layer is prepared, and then, using a three-kind, three-layer co-extruder equipped with a T-die, the resin material for forming the functional layer is extruded and molded at a predetermined temperature to produce a substrate film having a single-layer structure consisting of only the functional layer 2. As in the above-mentioned embodiment, the substrate film may be produced by a known calendar method or inflation method. EXAMPLES

[0082] The present invention will be described below based on examples. Note that the present invention is not limited to these examples, and these examples can be modified or changed based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

[0083] The materials used to prepare the base film are shown below. (1) LLDPE: Linear low-density polyethylene, melting point: 121°C, density: 0.922g / cm 3 , MFR: 1.6g / 10min (2) LDPE: Low-density polyethylene derived from plants, biomass content: 95%, density: 0.918 g / cm 3 , MFR(190℃):8.3g / 10min (3) 1-Bu: homopolymer of 1-butene, melting point: 128°C, density: 0.920g / cm 3 , MFR: 0.5g / 10min (4) PP elastomer 1: Propylene-based elastomer, density: 0.862 g / cm 3 , MFR: 3.0 g / 10 min (230° C.), polyethylene content: 16% (manufactured by Exxon Mobil Corporation, product name: Vistamax (registered trademark) 6102FL) (5) PP elastomer 2: Propylene-based elastomer, density: 0.889 g / cm 3 , MFR: 8.0 g / 10 min (230° C.), polyethylene content: 4% (manufactured by Exxon Mobil Corporation, product name: Vistamax (registered trademark) 3588FL) (6) Pentene copolymer: copolymer of 4-methyl-1-pentene and polypropylene, melting point: 130°C, density: 0.838g / cm 3 , MFR: 10.0g / 10min, 4-methyl-1-pentene content 85mol%, polypropylene content 15mol%

[0084] Example 1 <Preparation of base film> First, the materials shown in Table 1 were blended to prepare a resin material for forming a surface layer and a resin material for forming a functional layer having the composition (parts by mass) shown in Table 1. Next, these resin materials were simultaneously extruded through a T-die using a three-kind, three-layer co-extruder under conditions of a die temperature of 180 to 230°C and a chill roll temperature of 30°C to obtain a substrate film having the thickness shown in Table 1 and a three-layer structure in which the surface layer / functional layer / surface layer were laminated in this order.

[0085] Table 1 also shows the biomass content [mass %] of the entire base film.

[0086] In this embodiment, each surface layer contains 14 parts by mass of plant-derived low-density polyethylene (biomass content: 95%) per 100 parts by mass, and the total thickness of the two surface layers is 40 μm relative to the overall thickness of the base film (20 μm + 70 μm + 20 μm = 110 μm). Therefore, the biomass content of the entire base film is 95 × (14 / 100) × (40 / 110) = 4.8% by mass.

[0087] <Evaluation of the presence or absence of yield point> Using the produced base film, a sample for measurement was obtained in accordance with JIS K7161-2:2014. Next, the obtained sample for measurement was set in a tensile testing machine (manufactured by Shimadzu Corporation, product name: AG-5000A) so that the distance between the gripping tools was 40 mm, and a tensile test was conducted at a tensile speed of 300 mm / min in an environment where the temperature was 23°C and the relative humidity was 40% in accordance with JIS K7161-2:2014.

[0088] Then, in the S-S curves (stress-strain curves) in the MD and TD directions, those in which no yield point was confirmed during the elongation from an elongation rate of 0% to 100% (no necking occurs and uniform expansion is surely possible) were marked as ◎, those in which almost no yield point was confirmed during the elongation from an elongation rate of 0% to 100% (necking generation is suppressed and almost uniform expansion is possible) were marked as 〇, and those in which a yield point was confirmed (necking occurs and uniform expansion is impossible) were marked as ×. The above results are shown in Table 1.

[0089] <Measurement of stress in MD and TD> Using the produced base film, a sample for measurement was obtained in accordance with JIS K7161-2:2014. Next, the obtained sample for measurement was set in a tensile testing machine (manufactured by Shimadzu Corporation, product name: AG-5000A) so that the distance between the gripping tools was 40 mm, and a tensile test was conducted at a tensile speed of 300 mm / min in an environment where the temperature was 23°C and the relative humidity was 40% in accordance with JIS K7161-2:2014.

[0090] Then, the stress at 20% elongation (20% stress) in the MD and TD directions of the base film was measured, and the ratio of the stress in the MD direction (at 20% elongation) to the stress in the TD direction (at 20% elongation) (that is, the stress ratio of the base film at 20% elongation) was calculated. The above results are shown in Table 1.

[0091] Similarly, the stress at 40% elongation (40% stress) was measured in the MD and TD of the substrate film, and the ratio of the stress (at 40% elongation) to the stress (at 20% elongation) in the MD (i.e., the elongation rate of the substrate film in the MD) and the ratio of the stress (at 40% elongation) to the stress (at 20% elongation) in the TD (i.e., the elongation rate of the substrate film in the TD) were calculated. The results are shown in Table 1.

[0092] Similarly, the stress at 5% elongation (5% stress) was measured in the MD and TD of the substrate film, and the ratio of the stress (at 5% elongation) to the stress (at 40% elongation) in the MD and the ratio of the stress (at 5% elongation) to the stress (at 40% elongation) in the TD were calculated. The results are shown in Table 1.

[0093] <Calculation of stress relaxation rate> Using the prepared base film, a measurement sample having a No. 1 dumbbell shape (width 10 mm, length 120 mm) was obtained. Next, the obtained measurement sample was set in a tensile tester (manufactured by Shimadzu Corporation, product name: AG-5000A) so that the distance between the grippers was 80 mm, and the sample was stretched by 25% in the MD (or TD) at a tensile speed of 300 mm / min in an environment of a temperature of 23°C and a relative humidity of 40%.

[0094] The stress (initial stress S0) was measured when the specimen was stretched by 25%, and the specimen was held stretched for 60 seconds, after which the stress (stress after relaxation S1) was measured. The stress relaxation rate [%] of the substrate film in MD and TD was calculated from the difference between the initial stress S0 and the stress after relaxation S1 using the following formula (1). The results are shown in Table 1.

[0095] [Number 1] Stress relaxation rate [%] = [(initial stress S0 - stress after relaxation S1) / initial stress S0] × 100 (1)

[0096] (Examples 2 to 7, Comparative Examples 1 to 4) Except for changing the composition of the resin component to the composition (parts by mass) shown in Tables 1 and 2, a substrate film having the thickness shown in Tables 1 and 2 and a three-layer structure laminated in the order of surface layer / functional layer / surface layer was obtained in the same manner as in Example 1 described above.

[0097] The biomass ratio of the entire substrate film was calculated, the presence or absence of a yield point was evaluated, the stresses in MD and TD were measured, and the stress relaxation rate was calculated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[0098] The SS curves (stress-strain curves) in MD and TD for the substrate film of Example 1 are shown in Figure 2. As shown in Table 1, the ratio of stress (at 5% elongation) to stress (at 40% elongation) in MD and TD is 1.05 or less, and therefore, as shown in Figure 2, the SS curves (stress-strain curves) in MD and TD show no yield point between the elongation rate of 0% and 100%.

[0099] [Table 1]

[0100] [Table 2]

[0101] As shown in Table 1, in the substrate films of Examples 1 to 7, in which the functional layer contains a homopolymer of 1-butene, a copolymer of pentene, and a propylene-based elastomer, and the content of the propylene-based elastomer in the entire functional layer is 10% by mass or more and 40% by mass or less, the ratio of the stress (at 5% elongation) to the stress (at 40% elongation) in MD and TD is 1.05 or less, so that the occurrence of the yield point can be suppressed, and the ratio of the stress (at 40% elongation) to the stress (at 20% elongation) (i.e., the elongation rate of the substrate film in MD and TD) is 0.95 to 2 or less, so that necking does not occur, uniform expansion is possible, and it is found that the substrate films have excellent uniform elongation. In addition, the stress (at 20% elongation) in MD and TD is 7.0 MPa to 20 MPa, so that the substrate films have excellent rigidity. In addition, the stress relaxation rate is 25% or more, so that the substrate films have excellent stress relaxation.

[0102] Furthermore, as shown in Table 1, in the base films of Examples 1 to 7, at least one of the functional layer and the surface layer contains plant-derived low-density polyethylene, and the biomass content of the entire base film is 4% by mass or more and less than 49% by mass, so that it is clear that the environmental load can be sufficiently reduced.

[0103] On the other hand, as shown in Table 2, in the substrate film of Comparative Example 1, since the functional layer and the surface layer contain only a propylene-based elastomer, the ratio of the stress (at 40% elongation) to the stress (at 20% elongation) (i.e., the elongation rate of the substrate film in MD and TD) is less than 0.95, which shows poor uniform elongation. In addition, the stress (at 20% elongation) in MD and TD is less than 7.0 MPa, which shows poor rigidity. In addition, since the functional layer and the surface layer do not contain plant-derived low-density polyethylene, it is not possible to sufficiently reduce the environmental load.

[0104] Furthermore, as shown in Table 2, in the base film of Comparative Example 2, the biomass content in the entire base film was 49 mass% or more, so there was an excess of biomass-derived low-density polyethylene with a low degree of crystallinity, and the stress in TD (at 20% elongation) was less than 7.0 MPa, indicating poor rigidity.

[0105] Furthermore, as shown in Table 2, in the base film of Comparative Example 3, the functional layer and surface layer do not contain plant-derived low-density polyethylene, and therefore it is understood that the environmental load cannot be sufficiently reduced.

[0106] Furthermore, as shown in Table 4, in the base film of Comparative Example 4, the content of the propylene-based elastomer in the entire functional layer was greater than 40 mass%, resulting in an excess of the propylene-based elastomer component with low crystallinity, and the stress in TD (at 20% elongation) being less than 7.0 MPa, indicating poor rigidity. [Industrial Applicability]

[0107] As described above, the present invention is suitable for use as a base film for a tape for manufacturing semiconductors. [Explanation of symbols]

[0108] 1. Base film 2. Functional Layer 3 Surface layer

Claims

1. A substrate film for a semiconductor manufacturing tape having a functional layer and a surface layer provided on at least one side of the functional layer, the functional layer comprises a homopolymer of 1-butene, a copolymer of pentene, and an olefin-based elastomer; The content of the olefin-based elastomer in the functional layer is 10% by mass or more and 40% by mass or less, At least one of the functional layer and the surface layer contains a plant-derived olefin-based resin, The biomass ratio in the entire substrate film for semiconductor manufacturing tape is 4% by mass or more and less than 49% by mass.

1. A substrate film for a tape for semiconductor manufacturing.

2. 2. The substrate film for a tape for semiconductor manufacturing according to claim 1, wherein the plant-derived olefin resin is a plant-derived polyethylene.

3. 2. The substrate film for a tape for semiconductor manufacturing according to claim 1, wherein the olefin-based elastomer is a propylene-based elastomer.

4. 2. The substrate film for a semiconductor manufacturing tape according to claim 1, wherein the content of the pentene copolymer in the entire functional layer is 10% by mass or more and 40% by mass or less.

5. 5. The substrate film for a tape for semiconductor production according to claim 1, wherein the pentene copolymer is a copolymer of 4-methyl-1-pentene and an α-olefin.

6. the surface layer comprises a homopolymer of 1-butene; 2. The substrate film for a tape for semiconductor production according to claim 1, wherein the content of the 1-butene homopolymer in the entire surface layer is more than 0 mass % and 30 mass % or less.

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