Substrate film for semiconductor manufacturing adhesive tape

Abstract

The base film (1) for a semiconductor manufacturing tape has at least a functional layer (2), the functional layer containing a 1-butene homopolymer, a pentene copolymer, and an olefin elastomer, and the content of the pentene copolymer is more than 0% by mass but less than 50% by mass with respect to the entire functional layer. The content of the olefin elastomer relative to the entire functional layer is more than 0% by mass but less than 50% by mass.

Description

Technical Field

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

[0002] As a method for manufacturing semiconductor devices such as IC chips, for example, the following method is widely used: using dicing, a wafer circuit having a circuit formed on a semiconductor wafer having a substantially circular plate shape is divided on a wafer semiconductor manufacturing tape (wafer dicing tape) to obtain individual semiconductor devices. After dicing, for example, the wafer dicing tape is stretched to form a gap (i.e., expand) between the semiconductor devices, and then each semiconductor device is picked up by a robot or the like.

[0003] In addition, as a semiconductor manufacturing tape for wafers, a dicing die attach film (DDAF: Dicing Die Attach Film) is used in which an adhesive layer is stacked on the adhesive layer of the above-mentioned wafer dicing tape. After the wafer circuit is divided by cutting on the dicing die attach film, the dicing die attach film is stretched to form a gap between the semiconductor devices, and then the adhesive layer is photocured, and the semiconductor device is peeled off the adhesive layer and picked up while the adhesive layer is adhered.

[0004] Wafer dicing tape or dicing die bonding film generally consists of an adhesive layer for fixing the wafer and a base film containing polyolefins, etc. For example, a base film consisting of a laminate of an intermediate layer and a surface layer is known, wherein the intermediate layer has a propylene-based random copolymer (β) as a main component, and the propylene-based random copolymer (β) is a random copolymer of propylene and ethylene and / or an α-olefin having a carbon number of 4 to 8, wherein the content of ethylene and / or an α-olefin having a carbon number of 4 to 8 is 6% by weight or more, and the density measured according to ASTM D1505 is 885 kg / m 3 Below; the surface layer is stacked on both sides of the intermediate layer, and its main component is a propylene random copolymer (α) with a content of ethylene and / or α-olefins having a carbon number of 4 to 8 less than that of the propylene random copolymer (β) and a high density (for example, refer to patent document 1).

[0005] In addition, there is also known a substrate film containing a polyolefin elastomer such as crystalline polypropylene, a copolymer of 4-methyl-1-pentene and propylene, having an internal haze of less than 20%, a gloss of less than 40% on at least one surface, a melting point of more than 150°C, and an enthalpy of fusion of 30 to 90 J / g (for example, refer to Patent Document 2).

[0006] In addition, there is known a substrate film comprising a thermoplastic resin A and a thermoplastic resin B. The thermoplastic resin A is a copolymer containing 70 mol% to 90 mol% of a structural unit derived from 4-methyl-1-pentene and 10 mol% to 30 mol% of a structural unit derived from an α-olefin having 2 or 3 carbon atoms, and the ratio of the structural unit derived from an α-olefin having 4 to 20 carbon atoms other than 4-methyl-1-pentene is 10 mol% or less; and the thermoplastic resin B is at least one polymer selected from the group consisting of ethylene polymers, propylene polymers, butene polymers, and 4-methyl-1-pentene polymers, and is a thermoplastic resin other than the thermoplastic resin A. The content of the thermoplastic resin A is 50 to 98% by mass relative to the total mass, and the content of the thermoplastic resin B is 2 to 50% by mass relative to the total mass (for example, see Patent Document 3).

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Publication No. 2018-65327

[0010] Patent Document 2: International Publication No. 2020 / 218468

[0011] Patent Document 3: International Publication No. 2014 / 208564 Summary of the invention

[0012] -Technical problem to be solved by the invention-

[0013] However, since the substrate film described in the above-mentioned Patent Document 1 uses a semi-crystalline resin instead of an amorphous resin, there are problems such as necking when the substrate film is stretched to form a gap between semiconductor devices and insufficient uniform elongation of the substrate film. In addition, since the substrate film lacks rigidity, there are problems such as unstable unwinding of the substrate and tape formation including application of an adhesive in the manufacturing process of the substrate film.

[0014] Furthermore, the substrate film described in Patent Document 2 has sufficient flexibility and transparency and is excellent in blocking resistance, but has a problem of lacking uniform elongation due to the occurrence of necking and a yield point.

[0015] Furthermore, the base film described in Patent Document 3 has excellent stress relaxation properties and impact resistance, but has a problem of lacking uniform elongation due to the presence of a yield point.

[0016] Therefore, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a substrate film for an adhesive tape for semiconductor manufacturing having excellent uniform elongation, rigidity and stress relaxation properties.

[0017] -Technical solutions to solve technical problems-

[0018] In order to achieve the above-mentioned purpose, the substrate film for semiconductor manufacturing tape of the present invention is characterized in that it has at least a functional layer, the functional layer contains a homopolymer of 1-butene, a copolymer of pentene and an olefin-based elastomer, the content of the copolymer of pentene relative to the whole functional layer is greater than 0 mass% and less than 50 mass%, and the content of the olefin-based elastomer relative to the whole functional layer is greater than 0 mass% and less than 50 mass%.

[0019] - Effects of the Invention -

[0020] According to the present invention, it is possible to provide a substrate film for a semiconductor manufacturing tape having excellent uniform elongation, rigidity, and stress relaxation properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 2 is a cross-sectional view showing a substrate film for a semiconductor manufacturing tape according to an embodiment of the present invention;

[0022] Figure 2 is the S-S curve (stress-strain curve) of the substrate film of Example 9;

[0023] Figure 3 is the S-S curve (stress-strain curve) of the substrate film of Example 8;

[0024] Figure 4 This is an S-S curve (stress-strain curve) of the base film of Comparative Example 3. DETAILED DESCRIPTION

[0025] Hereinafter, the substrate film for semiconductor manufacturing tape of the present invention will be specifically described. It should be noted that the present invention is not limited to the following embodiments, and can be applied with appropriate changes within the scope of the present invention.

[0026] The base film of the present invention is a base film composed of a laminate composed of a functional layer (intermediate layer) and a surface layer provided on at least one side of the functional layer.

[0027] Examples of the substrate film having a multilayer structure include: Figure 1 The substrate film 1 shown is composed of a laminate of a functional layer 2 and surface layers 3 laminated on both surfaces of the functional layer 2, and has a three-layer structure laminated in the order of surface layer / functional layer / surface layer.

[0028] Examples of the functional layer include a functional layer containing a homopolymer of 1-butene, a copolymer of pentene, and an olefin-based elastomer.

[0029] <Homopolymer of 1-butene>

[0030] In the present invention, as polybutene, a homopolymer obtained by polymerizing 1-butene alone is used. Since the homopolymer of 1-butene has a high molecular weight and a bulky side chain, although the homopolymer of 1-butene is a crystalline polymer, the strong intermolecular force generated by the bulky side chain can improve the uniform elongation of the substrate film like an amorphous polymer.

[0031] 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.

[0032] It should be noted that the “weight average molecular weight” refers to a value calculated according to Japanese Industrial Standard JIS K 7252-1:2016.

[0033] Since the homopolymer of 1-butene used in the present invention has a high molecular weight, it has low surface adhesion. In addition, since it has higher rigidity than amorphous polyolefins, it is possible to provide a substrate film having high rigidity, which allows the substrate to be unwound during the manufacturing process of the substrate film and can be tape-formed including coating with an adhesive.

[0034] As described above, by using a homopolymer of 1-butene as the resin forming the base film, the uniform elongation and rigidity of the base film can be improved.

[0035] It should be noted that, from the viewpoint of improving uniform elongation and rigidity, the content of the homopolymer of 1-butene relative to the entire functional layer 2 is preferably 30% by mass or more and 85% by mass or less in 100% by mass of the functional layer, and more preferably 30% by mass or more and 60% by mass or less in 100% by mass of the functional layer.

[0036] <Copolymer of pentene>

[0037] The base film 1 of the present invention contains a copolymer of pentene as polypentene in order to improve the stress relaxation property so as to maintain the size of the semiconductor manufacturing tape after expansion. Since the stress relaxation property of the base film 1 is improved by using such a copolymer of pentene, the semiconductor manufacturing tape can be held by the clamp ring and the intervals between the semiconductor devices (semiconductor chips) can be maintained.

[0038] The copolymer of pentene is not particularly limited, but preferably is 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, and has good flexibility due to the α-olefin as a copolymer component. For example, there can be mentioned a copolymer of 4-methyl-1-pentene and polypropylene, namely, a product name "ABSORTOMER (registered trademark) EP-1013" manufactured by Mitsui Chemicals, Inc., a product name "ABSORTOMER (registered trademark) EP-1001" manufactured by Mitsui Chemicals, Inc., and the like.

[0039] It should be noted that when a copolymer of 4-methyl-1-pentene and polypropylene is used, the content of polypropylene relative to the entire copolymer of 4-methyl-1-pentene and polypropylene is preferably 10 mol% or more and 30 mol% or less in 100 mol% of the copolymer of 4-methyl-1-pentene and polypropylene from the viewpoint of improving flexibility and stress relaxation properties.

[0040] From the viewpoint of improving stress relaxation, the content of the copolymer of pentene relative to the entire functional layer 2 is more than 0% by mass and less than 50% by mass in 100% by mass of the functional layer. It should be noted that when the content of the copolymer of pentene is 50% by mass or more, the content of the homopolymer of 1-butene that contributes to uniform elongation is reduced, so that the uniform elongation may be reduced.

[0041] The content of the copolymer of pentene based on the entire functional layer 2 is preferably 10% by mass or more and 40% by mass or less in 100% by mass of the functional layer.

[0042] <Olefin-based elastomer>

[0043] In the substrate film 1 of the present invention, the functional layer 2 contains an olefin-based elastomer. The olefin-based elastomer is formed by an olefin-based material that conforms to the definition of elastomer terms in JIS K6200. More specifically, a material formed by a copolymer of amorphous or low-crystalline α-olefins is equivalent to an olefin-based elastomer, and a material with polyethylene as the main component is called an ethylene-based elastomer, and a material with polypropylene as the main component is called a propylene-based elastomer. For example, as an ethylene-based elastomer, there is a product name "TAFMER (registered trademark)" manufactured by Mitsui Chemicals, and as a propylene-based elastomer, there is a product name "Vistamaxx (registered trademark)" manufactured by Exxon Mobil.

[0044] When a propylene-based elastomer is used, the content of polyethylene relative to the entire propylene-based elastomer is preferably 9% to 30% based on 100% of the propylene-based elastomer from the viewpoint of improving flexibility.

[0045] By using such an olefin-based elastomer, the crystallinity is reduced and the occurrence of a yield point can be suppressed, so that the uniform elongation of the base film can be improved.

[0046] From the viewpoint of improving uniform elongation, the content of the olefin elastomer relative to the entire functional layer 2 is more than 0% by mass and less than 50% by mass in 100% by mass of the functional layer. When the content of the olefin elastomer is 50% by mass or more, the olefin elastomer component with low crystallinity is excessive, so the rigidity is reduced, and it may be difficult to unwind the substrate and form a tape including applying an adhesive.

[0047] The content of the olefin-based elastomer relative to the entire functional layer 2 is preferably 5% by mass or more and 40% by mass or less in 100% by mass of the functional layer.

[0048] From the viewpoint of further improving uniform elongation, the density of the olefin-based elastomer is preferably 0.850 to 0.900 g / cm 3 , more preferably 0.860 to 0.890 g / cm 3 .

[0049] In the base film 1 of the present invention, the functional layer 2 may contain a polyolefin-based resin such as polyethylene or polypropylene.

[0050] As polypropylene, for example, homopolymers of polypropylene and copolymers of polypropylene can be cited. Among them, the homopolymer of polypropylene is a homopolypropylene obtained by polymerizing propylene alone, and the homopolymer of polypropylene has high stereoregularity, a large crystallinity that contributes to the melting point, and therefore excellent heat resistance. Furthermore, since the crystallinity is large, the rigidity is large, but by mixing with the linear low-density polyethylene described later, the softness that contributes to the expansibility of the substrate film can be obtained.

[0051] <Low-density polyethylene>

[0052] The functional layer 2 preferably contains a polyolefin resin having a density of 0.930 g / cm 3 The density of low-density polyethylene (LDPE) is 0.930 g / cm 3 In the following cases, excessive increase in crystallinity is suppressed and flexibility is improved, thereby improving the isotropy of the substrate film. It should be noted that when the density of the low-density polyethylene is greater than 0.930 g / cm 3 In the case of , the crystallinity may be excessively increased, and the isotropy may be reduced. In addition, since the rigidity becomes too large, the pickup property of the semiconductor device is reduced, and the semiconductor device may be damaged.

[0053] From the viewpoint of improving processing stability, the density of the low-density polyethylene is preferably 0.860 g / cm 3More preferably 0.880 g / cm 3 above.

[0054] Among low-density polyethylenes, linear low-density polyethylene (LLDPE) has side chain branches in the linear structure of high-density polyethylene, and therefore has a less high crystallinity than high-density polyethylene and is superior in flexibility.

[0055] In addition, from the viewpoint of strength, linear low-density polyethylene produced by a metallocene catalyst or a Ziegler catalyst can be used.

[0056] The melt mass flow rate (MFR) of the linear low-density polyethylene is preferably 0.5 g to 7.5 g / 10 min, more preferably 1.0 to 6.0 g / 10 min, and further preferably 2.0 g to 5.0 g / 10 min. This is because, when the melt mass flow rate (MFR) of the linear low-density polyethylene is 0.5 g / 10 min or more, the molecular weight will not be too large, and the flexibility and processability can be improved; when it is 7.5 g / 10 min or less, the molecular weight will not be too small, and the processing stability can be improved.

[0057] It should be noted that the melt mass flow rate can be measured according to the provisions of JIS K7210:1999.

[0058] From the viewpoint of improving uniform elongation and rigidity, the content of the linear low-density polyethylene relative to the entire functional layer 2 is preferably 20% by mass or more and 25% by mass or less in 100% by mass of the functional layer.

[0059] As mentioned above, by using a density of 0.93 g / cm 3 The following low-density polyethylene is used as the resin forming the functional layer 2, and can improve the flexibility and isotropy of the base film.

[0060] Next, the surface layer 3 of the substrate film 1 of the present invention is described. As the surface layer 3, for example, a surface layer containing a polyolefin resin such as a homopolymer of 1-butene, polyethylene, polypropylene, etc. It should be noted that as the polyolefin resin, the same polyolefin resin as the polyolefin resin of the functional layer 2 can be used.

[0061] Although the homopolymer of 1-butene has a high molecular weight, it can be formed by a general extruder. The surface adhesion of the film is low due to the high molecular weight component, so when the homopolymer of 1-butene is used in the surface layer, it is possible to suppress the adhesion of the substrate film to the conveying roller when the substrate film is conveyed, and it is possible to suppress the adhesion when the substrate film is rolled up and the draw resonance when the substrate film is formed, thereby improving the processing stability of the substrate film.

[0062] Density: 0.860g / cm 3 Above 0.93g / cm 3 The following low-density polyethylene has low surface adhesion. Therefore, when low-density polyethylene is used in the surface layer, it can inhibit the adhesion of the substrate film to the conveying roller when the substrate film is conveyed, and can inhibit the adhesion of the substrate film when it is rolled up, thereby improving the processing stability of the substrate film.

[0063] From the viewpoint of suppressing surface adhesion, the ratio of the content of the homopolymer of 1-butene to the content of the low-density polyethylene in the surface layer 3 (i.e., each surface layer 3 stacked on the two surfaces of the functional layer 2) is preferably 1-butene homopolymer: low-density polyethylene = 0:100 to 30:70.

[0064] <Base film>

[0065] The substrate film 1 of the present invention preferably has a stress (at 20% elongation) in the mechanical axis (length) direction (hereinafter referred to as "MD") and in the direction orthogonal thereto (hereinafter referred to as "TD") of 6.5 MPa or more and 20 MPa or less, more preferably 7.5 MPa or more and 15 MPa or less, and further preferably 8 MPa or more and 13 MPa or less. When the stress (at 20% elongation) in MD and TD is greater than 20 MPa, the pick-up property of the semiconductor device is reduced due to excessive rigidity, and the semiconductor device may be damaged; when the stress is less than 6.5 MPa, the rigidity is reduced, and therefore, in the manufacturing process of the substrate film, it may be difficult to unwind the substrate, and it may be difficult to tape the substrate including the application of the adhesive.

[0066] That is, when the stress in MD and TD (at 20% elongation) is 6.5 MPa or more and 20 MPa or less, a rigid substrate film can be provided which can be unwound during the manufacturing process of the substrate film and can be tape-formed including applying an adhesive.

[0067] In the case of a conventional polyolefin-containing substrate film, when the substrate film is stretched by 20%, necking does not occur and the film can be stretched uniformly. However, when the substrate film is stretched by 40%, necking begins to occur and uniform stretching becomes difficult.

[0068] Therefore, from the viewpoint of improving the uniform elongation of the substrate film, the ratio of stress (at 40% elongation) to stress (at 20% elongation) (i.e., the elongation of the substrate film) in the substrate film 1 of the present invention in MD and TD is preferably 0.95 or more and 2 or less. When the elongation of the substrate film is greater than 2, it is sometimes difficult to maintain the expansion loop due to the excessive increase in stress; when the elongation of the substrate film is less than 0.95, necking may occur, making it difficult to perform uniform expansion.

[0069] That is, when the elongation percentage of the base film is 0.95 or more and 2 or less, necking does not occur and the film can be expanded uniformly.

[0070] The elongation of the base film is more preferably 1.05 to 1.8, and from the viewpoint of preventing necking and enabling reliable uniform expansion, the elongation of the base film is further preferably 1.1 to 1.7.

[0071] From the viewpoint of further improving the uniform elongation of the substrate film, the ratio of stress (at 5% elongation) to stress (at 40% elongation) in the substrate film 1 of the present invention in MD and TD is preferably less than 1.05. If the ratio of stress (at 5% elongation) to stress (at 40% elongation) is less than 1.05, the occurrence of the yield point (the yield point during the elongation process from 0% to 100% at a tensile rate of 300 mm / min) described later can be suppressed, thereby suppressing the occurrence of necking and enabling uniform expansion.

[0072] It should be noted that the ratio of stress (at 5% elongation) to stress (at 40% elongation) is more preferably 0.40 or more and less than 1.05. From the viewpoint of preventing the occurrence of necking and reliably performing uniform expansion, the ratio of stress (at 5% elongation) to stress (at 40% elongation) is more preferably 0.50 or more and less than 0.90.

[0073] The stress relaxation rate of the substrate film 1 of the present invention is preferably 25% or more, more preferably 30% or more, and further preferably 35% or more. When the stress relaxation rate of the substrate film is less than 25%, it is sometimes difficult to maintain the size of the semiconductor manufacturing tape due to the lack of stress absorption performance.

[0074] That is, when the stress relaxation rate of the base film is 25% or more, the dimensions of the tape for semiconductor manufacturing can be maintained, and thus a base film for a tape for semiconductor manufacturing having excellent stress relaxation properties can be provided.

[0075] It should be noted that the “stress relaxation rate” referred to here can be obtained by the method described in Examples below.

[0076] From the viewpoint of suppressing relaxation by utilizing the isotropy of the substrate 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 substrate film at 20% elongation) is preferably greater than 0.8 and less than 1.2, more preferably greater than 0.85 and less than 1.15, and further preferably greater than 0.9 and less than 1.1.

[0077] The thickness of the substrate film 1 of the present invention is preferably 50 μm to 300 μm, and more preferably 80 μm to 150 μm. If the thickness of the substrate film is 50 μm or more, the operability is improved; if the thickness is 300 μm or less, the flexibility (expandability) can be improved. It should be noted that in the case of a substrate film for a wafer, the thickness of the substrate film is preferably 50 μm to 150 μm, and more preferably 70 μm to 110 μm.

[0078] For example, in the case of a substrate film having a three-layer structure stacked in the order of surface layer / functional layer / surface layer, the thickness of the surface layer is not particularly limited, preferably 2 to 60 μm, more preferably 4 to 40 μm. The thickness of the functional layer is not particularly limited, preferably 40 to 120 μm, more preferably 50 to 80 μm.

[0079] For example, in the case of a substrate film having a three-layer structure stacked in the order of surface layer / functional layer / surface layer, from the viewpoint of processability and low cost, the ratio of the functional layer to the entire substrate film is preferably 40 to 95%, more preferably 50 to 90%.

[0080] <Manufacturing method>

[0081] like Figure 1 As shown, when manufacturing the base film 1 having a three-layer structure stacked in the order of surface layer / functional layer / surface layer, first, a resin material for forming a surface layer and a resin material for forming a functional layer are prepared.

[0082] Next, using three types of three-layer co-extruders including a T-die, the resin material for forming the surface layer and the resin material for forming the functional layer are simultaneously extruded and formed at a predetermined temperature, thereby manufacturing the substrate film 1 having a multilayer structure of the present invention, the multilayer structure consisting of a laminate of a functional layer 2 and a surface layer 3 laminated on both surfaces of the functional layer 2. It should be noted that the substrate film of the present invention can also be manufactured by a known calendering method or inflation method.

[0083] <Other forms>

[0084] The base film 1 of the present invention may contain various additives. As additives, known additives commonly used in semiconductor manufacturing tapes can be used, for example, crosslinking aids, antistatic agents, heat stabilizers, antioxidants, ultraviolet absorbers, lubricants, antiblocking agents, colorants, nucleating agents, processing aids, etc. It should be noted that these additives can be used alone or in combination of two or more.

[0085] As a cross-linking aid, for example, triallyl isocyanurate and the like can be cited. When the substrate film contains a cross-linking aid, the content of the cross-linking aid in the substrate 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 substrate film.

[0086] Although a substrate film having a three-layer structure stacked in the order of surface layer / functional layer / surface layer has been described as an example, the substrate film having a multi-layer structure of the present invention only needs to be provided with the functional layer and is not limited to a three-layer structure. For example, it may also be a substrate film having a five-layer structure stacked in the order of surface layer / functional layer / functional layer / functional layer / surface layer.

[0087] In the above embodiment, the substrate film 1 having a three-layer structure stacked in the order of surface layer / functional layer / surface layer is described as an example, but the substrate film of the present invention may also be a substrate film having a single-layer structure consisting only of the functional layer 2.

[0088] In this case, first, a resin material for forming a functional layer is prepared, and then three types of three-layer co-extruders including a T-die are used to extrude the resin material for forming a functional layer at a predetermined temperature to form a substrate film having a single-layer structure consisting only of the functional layer 2. It should be noted that, as in the case of the above-mentioned embodiment, the substrate film can also be manufactured by a known calendering method or inflation method.

[0089] [Example]

[0090] The present invention is described below based on the following embodiments. It should be noted that the present invention is not limited to the following embodiments, and various modifications and changes can be made based on the following embodiments according to the main purpose of the present invention, and they all fall within the protection scope of the present invention.

[0091] The materials used to prepare the base film are as follows.

[0092] (1) LLDPE-1: Linear low-density polyethylene, melting point: 121°C, density: 0.922 g / cm 3 , MFR: 1.6g / 10 minutes

[0093] (2) LLDPE-2: Linear low-density polyethylene, melting point: 119°C, density: 0.923 g / cm 3 , MFR: 3.8 g / 10 min (manufactured by PRIME POLYMER, trade name: Evolue (registered trademark) SP2540)

[0094] (3) 1-Bu: Homopolymer of 1-butene, melting point: 128°C, density: 0.920 g / cm 3 、MFR: 0.5g / 10min

[0095] (4) PP elastomer 1: propylene elastomer, density: 0.862 g / cm 3 , MFR: 3.0 g / 10 minutes (230°C), polyethylene content: 16% (manufactured by Exxon Mobil Corporation, trade name: Vistamaxx (registered trademark) 6102FL)

[0096] (5) PP elastomer 2: propylene elastomer, density: 0.889 g / cm 3 , MFR: 8.0 g / 10 minutes (230°C), polyethylene content 4% (manufactured by Exxon Mobil Corporation, trade name: Vistamaxx (registered trademark) 3588FL)

[0097] (6) Copolymer of pentene 1: Copolymer of 4-methyl-1-pentene and polypropylene, melting point: 130°C, density: 0.838 g / cm 3 , MFR: 10.0 g / 10 minutes, 4-methyl-1-pentene content 85 mol%, polypropylene content 15 mol%

[0098] (7) Copolymer of pentene 2: Copolymer of 4-methyl-1-pentene and polypropylene, amorphous, density: 0.84 g / cm 3 , MFR: 10.0 g / 10 minutes, 4-methyl-1-pentene content 71.9 mol%, polypropylene content 28.1 mol%

[0099] (8) h-PP: homopolymer of polypropylene, density: 0.90 g / cm 3 , MFR: 3.0 g / 10 min (manufactured by SunAllomer, trade name: SunAllomer (registered trademark) PL500A)

[0100] (Example 1)

[0101] <Production of base film>

[0102] First, the materials shown in Table 1 were mixed 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, three types of three-layer co-extruders were used to simultaneously extrude the resin materials using a T-die head at a die temperature of 180 to 230° C. and a cooling roll temperature of 30° C., thereby obtaining a substrate film having a three-layer structure stacked in the order of surface layer / functional layer / surface layer and having the thickness shown in Table 1.

[0103] <Evaluation of the existence of yield point>

[0104] Using the produced substrate film, a sample for measurement was obtained in accordance with JIS K7161-2: 2014. Next, the obtained sample for measurement was set on a tensile testing machine (manufactured by Shimadzu Corporation, trade name: AG-5000A) with a distance between the clamps being 40 mm, and a tensile test was performed in accordance with JIS K7161-2: 2014 at a temperature of 23° C. and a relative humidity of 40% at a tensile rate of 300 mm / min.

[0105] For the S-S curves (stress-strain curves) of MD and TD, the curves in which the yield point was not confirmed during the elongation process from 0% to 100% at an elongation rate (the curve in which necking did not occur and uniform extension could be reliably performed) were set as ◎; the curves in which the yield point was almost not confirmed during the elongation process from 0% to 100% at an elongation rate (the curve in which the occurrence of necking was suppressed and roughly uniform extension could be performed) were set as 0; the curves in which the yield point was confirmed (the curve in which necking occurred and uniform extension could not be performed) were set as ×. The above results are shown in Table 1.

[0106] <Measurement of stress in MD and TD>

[0107] Using the produced substrate film, a sample for measurement was obtained in accordance with JIS K7161-2: 2014. Next, the obtained sample for measurement was set on a tensile testing machine (manufactured by Shimadzu Corporation, trade name: AG-5000A) with a distance between the clamps being 40 mm, and a tensile test was performed in accordance with JIS K7161-2: 2014 at a temperature of 23° C. and a relative humidity of 40% at a tensile rate of 300 mm / min.

[0108] Then, the stress (20% stress) at 20% elongation in MD and TD of the substrate film was measured, and the ratio of the stress (20% elongation) in MD to the stress (20% elongation) in TD was calculated (i.e., the stress ratio of the substrate film at 20% elongation). The above results are shown in Table 1.

[0109] Similarly, the stress (40% stress) at 40% elongation in MD and TD of the substrate film was measured, and the ratio of the stress (40% elongation) to the stress (20% elongation) in MD (i.e., the elongation of the substrate film in MD) and the ratio of the stress (40% elongation) to the stress (20% elongation) in TD (i.e., the elongation of the substrate film in TD) were calculated. The above results are shown in Table 1.

[0110] Similarly, the stress (5% stress) at 5% elongation in MD and TD of the substrate film was measured, and the ratio of the stress (5% elongation) to the stress (40% elongation) in MD and the ratio of the stress (5% elongation) to the stress (40% elongation) in TD were calculated. The above results are shown in Table 1.

[0111] <Calculation of stress relaxation rate>

[0112] Using the produced base film, a measurement sample having a dumbbell shape (width 10 mm, length 120 mm) was obtained. Next, the obtained measurement sample was set on a tensile tester (manufactured by Shimadzu Corporation, trade name: AG-5000A) in a manner such that the distance between the clamps was 80 mm, and the sample was stretched 25% in MD (or TD) at a stretching rate of 300 mm / min under an environment of a temperature of 23°C and a relative humidity of 40%.

[0113] Then, the stress at 25% elongation (initial stress S0) was measured, and the elongation of the test piece was maintained for 60 seconds, and the stress after 60 seconds (relaxed stress S1) was measured. Then, the stress relaxation rate [%] in MD and TD of the substrate film was calculated from the difference between the initial stress S0 and the relaxed stress S1 using the following formula (1). The above results are shown in Table 1.

[0114] [Formula 1]

[0115] Stress relaxation rate [%] = [(initial stress S0 - stress after relaxation S1) / initial stress S0] × 100 (1)

[0116] (Example 2 to Example 11, Comparative Example 1 to Comparative Example 6)

[0117] Except for changing the composition of the resin component to the composition (mass parts) shown in Tables 1 and 2, other aspects are the same as the above-mentioned Example 1, and a substrate film having a three-layer structure stacked in the order of surface layer / functional layer / surface layer is obtained having the thickness shown in Tables 1 and 2.

[0118] Then, the presence or absence of a yield point was evaluated, the stress in MD and TD was measured, and the stress relaxation rate was calculated in the same manner as in Example 1. The above results are shown in Tables 1 and 2.

[0119] It should be noted that the S-S curve (stress-strain curve) of MD and TD of the substrate film of Example 9 is shown in Figure 2 As shown in Table 1, in MD and TD, the ratio of stress (at 5% elongation) to stress (at 40% elongation) is greater than 0.50 and less than 0.90. Figure 2 As shown, it is known that in the S-S curves (stress-strain curves) in MD and TD, there is no yield point in the elongation process from 0% to 100% at an elongation rate.

[0120] The S-S curve (stress-strain curve) of MD and TD of the substrate film of Example 8 is shown in Figure 3 As shown in Table 1, in MD and TD, the ratio of stress (at 5% elongation) to stress (at 40% elongation) is greater than 0.40 and less than 1.05. Figure 3 As shown, in the S-S curve (stress-strain curve) in MD and TD, it is found that there is almost no yield point in the elongation process from 0% to 100% at an elongation rate.

[0121] The S-S curve (stress-strain curve) of MD and TD of the substrate film of Comparative Example 3 is shown in FIG. Figure 4 As shown in Table 2, in MD and TD, the ratio of stress (at 5% elongation) to stress (at 40% elongation) is 1.05 or more. Figure 4 As shown, it can be seen that in the S-S curve (stress-strain curve) in MD and TD, there is a yield point in the elongation process of elongation from 0% to 100%.

[0122] (Example 12)

[0123] First, the materials shown in Table 3 were mixed to prepare a resin material for forming a functional layer having the composition (mass parts) shown in Table 3. Next, the resin material was extruded using three types of three-layer co-extruders using a T-die head at a die temperature of 180 to 230° C. and a cooling roll temperature of 30° C., thereby obtaining a substrate film having a single-layer structure consisting only of a functional layer and having a thickness shown in Table 3.

[0124] Then, the presence or absence of a yield point was evaluated, the stress in MD and TD was measured, and the stress relaxation rate was calculated in the same manner as in Example 1. Table 3 shows the results.

[0125] (Example 13 to Example 16)

[0126] Except for changing the composition of the resin component to the composition (mass parts) shown in Table 3, the same procedures as in Example 12 were carried out to obtain a substrate film having a single-layer structure having the thickness shown in Table 3 and consisting only of a functional layer.

[0127] Then, the presence or absence of a yield point was evaluated, the stress in MD and TD was measured, and the stress relaxation rate was calculated in the same manner as in Example 1. Table 3 shows the results.

[0128] [Table 1]

[0129]

[0130] [Table 2]

[0131]

[0132] [Table 3]

[0133]

[0134] As shown in Table 1, it can be seen that the functional layer contains a homopolymer of 1-butene, a copolymer of pentene, and a propylene-based elastomer, and the content of the pentene copolymer relative to the entire functional layer exceeds 0% by mass and is less than 50% by mass (10% by mass or more and 40% by mass or less), and the content of the propylene-based elastomer relative to the entire functional layer exceeds 0% by mass and is less than 50% by mass (5% by mass or more and 40% by mass or less). That is, the substrate films of Examples 1 to 11 have a ratio of stress (at 5% elongation) to stress (at 40% elongation) of less than 1.05 in MD and TD, so the occurrence of a yield point can be suppressed, and the ratio of stress (at 40% elongation) to stress (at 20% elongation) (that is, the elongation of the substrate film in MD and TD) is 0.95 or more, so that necking does not occur, and it can be uniformly extended, and the uniform elongation is excellent. Since the stress (at 20% elongation) in MD and TD is 6.5 MPa or more and 20 MPa or less, it is known that the rigidity is excellent. Since the stress relaxation rate is 25% or more, it is understood that the stress relaxation property is excellent.

[0135] On the other hand, as shown in Table 2, since the functional layer of the substrate film of Comparative Example 1 is formed only of a propylene-based elastomer, the ratio of stress in MD and TD (at 40% elongation) to stress (at 20% elongation) (i.e., the elongation in MD and TD of the substrate film) is less than 0.95, indicating a lack of uniform elongation. The stress in MD and TD (at 20% elongation) is less than 6.5 MPa, indicating a lack of rigidity.

[0136] As shown in Table 2, the substrate film of Comparative Example 2 does not contain a homopolymer of 1-butene and a propylene-based elastomer in the functional layer. Therefore, in MD and TD, the ratio of stress (at 5% elongation) to stress (at 40% elongation) is greater than 1.05, and the yield point is confirmed. The ratio of stress (at 40% elongation) to stress (at 20% elongation) (that is, the elongation of the substrate film in MD and TD in MD and TD) is less than 0.95, which shows that necking occurs and uniform elongation is lacking.

[0137] As shown in Table 2, the substrate film of Comparative Example 3 does not contain a homopolymer of 1-butene and a propylene-based elastomer in the functional layer. Therefore, in MD and TD, the ratio of stress (at 5% elongation) to stress (at 40% elongation) is greater than 1.05, and the yield point is confirmed, indicating a lack of uniform elongation.

[0138] As shown in Table 2, in the base film of Comparative Example 4, the content of pentene copolymer relative to the whole functional layer is more than 50 mass %, so on MD, the ratio of stress (at 5% elongation) to stress (at 40% elongation) is more than 1.05, and the yield point is confirmed, which shows the lack of uniform elongation.

[0139] As shown in Table 2, the substrate film of Comparative Example 5 does not contain a copolymer of pentene in the functional layer, and therefore has a stress relaxation rate of less than 25%, indicating that the substrate film lacks stress relaxation properties.

[0140] As shown in Table 2, the base film of Comparative Example 6 has a propylene elastomer content of 50 mass % or more relative to the entire functional layer, and therefore has a stress in TD (at 20% elongation) of less than 6.5 MPa, indicating a lack of rigidity.

[0141] As shown in Table 3, the substrate film having a single-layer structure consisting only of a functional layer contains a homopolymer of 1-butene, a copolymer of pentene, and a propylene-based elastomer, the content of the copolymer of pentene relative to the entire substrate film exceeds 0% by mass and is less than 50% by mass (10% by mass or more and 40% by mass or less), and the content of the propylene-based elastomer relative to the entire substrate film exceeds 0% by mass and is less than 50% by mass (10% by mass or more and 30% by mass or less). In other words, the substrate films of Examples 12 to 16 can suppress the occurrence of a yield point because the ratio of stress (at 5% elongation) to stress (at 40% elongation) in MD and TD is less than 1.05. The ratio of stress (at 40% elongation) to stress (at 20% elongation) (i.e., the elongation in MD and TD of the substrate film) is 0.95 or more, so that necking does not occur, and the film can be uniformly extended, and the uniform elongation is excellent. Since the stress in MD and TD (at 20% elongation) is 6.5 MPa or more and 20 MPa or less, it is known that the rigidity is excellent. Since the stress relaxation rate is 25% or more, it is known that the stress relaxation property is excellent.

[0142] - Industrial Applicability -

[0143] As described above, the present invention is applicable to a base film for a semiconductor manufacturing tape.

[0144] - Explanation of symbols -

[0145] 1. Base film

[0146] 2. Functional layer (substrate film)

[0147] 3 surface layer.

Claims

1. A substrate film for a semiconductor manufacturing tape, the substrate film for a semiconductor manufacturing tape having at least a functional layer, characterized in that: The functional layer contains a homopolymer of 1-butene, a copolymer of pentene and an olefin-based elastomer. The content of the pentene copolymer relative to the entire functional layer is more than 0% by mass and less than 50% by mass, The content of the olefin-based elastomer relative to the entire functional layer is more than 0% by mass and less than 50% by mass.

2. The substrate film for semiconductor manufacturing tape according to claim 1, characterized in that: The olefin-based elastomer is a propylene-based elastomer.

3. The substrate film for semiconductor manufacturing tape according to claim 1 or 2, characterized in that: The pentene copolymer is a copolymer of 4-methyl-1-pentene and α-olefin.

4. The substrate film for semiconductor manufacturing tape according to claim 1 or 2, characterized in that: The substrate film for semiconductor manufacturing tape has a surface layer provided on at least one side of the functional layer. The surface layer contains at least a density of 0.93 g / cm 3 The following low density polyethylene.

5. The substrate film for semiconductor manufacturing tape according to claim 4, characterized in that: The surface layer contains a homopolymer of 1-butene.

Images