Substrate film for semiconductor-manufacturing tapes

Abstract

The present invention aims to provide a substrate film for semiconductor manufacturing tape, which contains at least a homopolymer of 1-butene, and has no yield point during elongation from 0% to 100% at a stretching speed of 300 mm / min, and a stress (at 25% elongation) of 5 MPa or more and 20 MPa or less.

Description

Technical Field

[0001] This invention relates to a substrate film (hereinafter, sometimes simply referred to as "substrate film") for use in manufacturing semiconductor tapes. Prior Technology

[0002] As a method for manufacturing semiconductor devices such as IC chips, a widely used approach is to divide the wafer circuitry formed on a roughly circular semiconductor wafer by cutting (dicing) on ​​a semiconductor manufacturing tape (wafer dicing tape) to obtain individual semiconductor devices. After cutting, for example, the wafer dicing tape is stretched to create gaps (i.e., expand) between the semiconductor devices, and then the individual semiconductor devices are picked up by a robot or the like.

[0003] As a semiconductor manufacturing tape for wafers, a die-attach film (DDAF) with an adhesive layer is deposited on the adhesive layer of the aforementioned wafer dicing tape. After the wafer circuit is divided by cutting on the die-attach film, the die-attach film is stretched to form gaps between semiconductor devices. Then, the adhesive layer is photocured, and the semiconductor devices are peeled off from the adhesive layer and picked up while the adhesive layer is attached.

[0004] Wafer dicing tapes and dicing / die bonding films are generally formed by an adhesive layer that fixes the wafer and a substrate film containing polyolefins, etc. For example, wafer dicing tapes including a substrate film are known, which are composed of a laminate of a polyolefin layer (intermediate layer) and a polyethylene resin layer (surface layer). The aforementioned polyolefin layer (intermediate layer) contains: 30 to 100% by weight of an amorphous polyolefin with a content of 50% or more of propylene and / or 1-butene, 0 to 70% by weight of a crystalline polypropylene resin, and 0 to 70% by weight of a polyethylene resin. The aforementioned polyethylene resin layer (surface layer) is laminated on both sides of the polyolefin layer and is formed of a polyethylene resin such as low-density polyethylene (for example, see Patent Document 1).

[0005] In addition, there are known substrate films composed of a laminate of an intermediate layer and a surface layer, wherein the intermediate layer contains at least 40% by mass of an amorphous polyolefin selected from the group consisting of ethylene, propylene, and 1-butene; and the surface layer is laminated on both sides of the intermediate layer and is mainly composed of crystalline polyethylene (for example, see Patent Document 2).

[0006] A substrate film is known to be composed of a laminate consisting of an intermediate layer and a surface layer. The intermediate layer is mainly composed of an propylene random copolymer (β), which is a random copolymer of propylene and ethylene and / or α-olefins with 4 to 8 carbons. The content of ethylene and / or α-olefins with 4 to 8 carbons is 6% by weight or more, and the density measured according to ASTM D1505 is 885 kg / m3 or less. The surface layer is laminated on both sides of the intermediate layer and is mainly composed of an propylene random copolymer (α) with less ethylene and / or α-olefins with 4 to 8 carbons than the propylene random copolymer (β) and with a higher density (for example, see Patent Document 3).

[0007] Patent Document 1: Japanese Patent Application Publication No. 11-323273

[0008] Patent Document 2: Japanese Patent Application Publication No. 2001-232683

[0009] Patent Document 3: Japanese Patent Application Publication No. 2018-65327 Summary of the Invention

[0010] -The technical problem the invention aims to solve-

[0011] However, the substrate film described in Patent Document 1, due to the addition of an equal or greater amount of crystalline atactic polypropylene compared to the amorphous butene copolymer, experiences necking during elongation, resulting in insufficient uniformity of elongation (uniform spreadability). Furthermore, the use of a low-viscosity butene copolymer leads to increased thickness variations caused by ejection variations such as pull resonance during substrate film forming, resulting in insufficient processing stability of the substrate film.

[0012] The substrate film described in the aforementioned Patent Document 2 has insufficient rigidity, resulting in instability during the unwinding process of the substrate film during manufacturing.

[0013] The substrate film described in Patent Document 3, due to the use of a semi-crystalline resin instead of an amorphous resin, suffers from problems such as necking during substrate film forming and insufficient uniformity of substrate film elongation. Due to insufficient rigidity of the substrate film, the unwinding process becomes unstable during substrate film manufacturing. Furthermore, the high adhesiveness of the substrate film surface leads to the following problems: the substrate film adheres to the conveyor rollers during transport, making transport and winding difficult, and adhesion occurs during winding, resulting in insufficient processing stability.

[0014] Therefore, the present invention was made in view of the above-mentioned problems, and its object is to provide a substrate film for semiconductor manufacturing tape with excellent elongation uniformity, rigidity and processing stability.

[0015] -Technical means for solving technical problems-

[0016] To achieve the above objectives, the substrate film for semiconductor manufacturing tape of the present invention is characterized by: containing at least a homopolymer of 1-butene, having no yield point during elongation from 0% to 100% at a stretching speed of 300 mm / min, and having a stress (at 25% elongation) of 5 MPa or more and 20 MPa or less.

[0017] -The Effects of the Invention-

[0018] According to the present invention, a substrate film for semiconductor manufacturing tapes with excellent elongation uniformity, rigidity and processing stability can be provided. Simple Explanation of the Diagram

[0019] Figure 1 is a cross-sectional view of a substrate film for semiconductor manufacturing tape relating to the second embodiment of the present invention.

[0020] Figure 2 shows the SS curve (stress-strain curve) on the MD of the substrate film of Example 1.

[0021] Figure 3 shows the SS curve (stress-strain curve) on the TD of the substrate film of Example 1.

[0022] Figure 4 shows the SS curve (stress-strain curve) on the MD of the substrate film of Example 10.

[0023] Figure 5 shows the SS curve (stress-strain curve) on the TD of the substrate film of Example 10. Implementation

[0024] The substrate film for semiconductor manufacturing tapes of the present invention will now be described in detail. It should be noted that the present invention is not limited to the following embodiments, and appropriate modifications can be made and applied without altering the spirit of the invention.

[0025] (First Implementation)

[0026] The substrate film in this embodiment is a film formed from a polyolefin resin, containing at least a homopolymer of 1-butene.

[0027] <Homopolymer of 1-butene>

[0028] In this embodiment, a homopolymer obtained by polymerizing 1-butene alone is used as polybutene. This homopolymer of 1-butene has a high molecular weight and large side chains. The strong intermolecular forces generated by these large side chains can improve the elongation uniformity of the substrate film, just like in the case of amorphous polymers, even though it is a crystalline polymer.

[0029] The homopolymer of 1-butene used in this embodiment can be a homopolymer with a weight average molecular weight (Mw) of approximately 500,000 to 1,500,000.

[0030] It should be noted that the "weight-average molecular weight" mentioned above refers to the value calculated according to JIS K 7252-1:2016.

[0031] Since the homopolymer of 1-butene used in this embodiment has a high molecular weight, it has low surface adhesion and can be used as a surface layer. In addition, since it has high rigidity compared with amorphous polyolefins, it can provide a substrate film with high rigidity that can be unwound during the substrate film manufacturing process.

[0032] Although the homopolymer of 1-butene used in this embodiment is of high molecular weight, it can be formed using a common extruder. The surface adhesion of the film is low due to the high molecular weight component, thus suppressing adhesion to the conveyor rollers when conveying the substrate film, suppressing adhesion during the winding of the substrate film and draw resonance during the forming of the substrate film, thereby improving the processing stability of the substrate film.

[0033] As described above, by using a homopolymer of 1-butene as the resin for forming the substrate film, the elongation uniformity, rigidity, and processing stability of the substrate film can be improved.

[0034] Low-density polyethylene

[0035] The substrate film of this embodiment contains low-density polyethylene with a density of 0.930 g / cm³ or less. When the density of low-density polyethylene is 0.930 g / cm³ or less, excessive increase in crystallinity is suppressed and flexibility is improved, thus enhancing the homogeneity of the substrate film. It should be noted that when the density of low-density polyethylene is greater than 0.930 g / cm³, excessive crystallinity can occur, sometimes reducing homogeneity. Furthermore, excessive rigidity can lead to reduced pick-up capability of semiconductor devices, and may sometimes damage the semiconductor devices.

[0036] From the perspective of improving processing stability, the density of low-density polyethylene is preferably above 0.860 g / cm3, and more preferably above 0.880 g / cm3.

[0037] Linear low-density polyethylene has side chain branches in the linear structure of high-density polyethylene, so its crystallinity is not too high and its flexibility is excellent compared with high-density polyethylene.

[0038] It should be noted that, in terms of strength, linear low-density polyethylene manufactured with metallocene catalysts or Ziegler catalysts can be used.

[0039] The melt flow rate (MFR) of 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 even more preferably 2.0 g to 5.0 g / 10 min. This is because when the melt flow rate (MFR) of linear low-density polyethylene is above 0.5 g / 10 min, the molecular weight will not be too large, which can improve flexibility and processability. When the melt flow rate (MFR) of linear low-density polyethylene is below 7.5 g / 10 min, the molecular weight will not be too small, which can improve processing stability.

[0040] It should be noted that the above-mentioned melt mass flow rate can be obtained by measurement in accordance with JIS K7210:1999.

[0041] As described above, by using low-density polyethylene with a density of less than 0.93 g / cm3 as the resin for forming the substrate film, the flexibility and homogeneity of the substrate film can be improved.

[0042] <Substrate Film>

[0043] In this embodiment, the stress (at 25% elongation) of the substrate film in the mechanical axis (length) direction (hereinafter referred to as "MD") and the direction orthogonal to it (hereinafter referred to as "TD") is 5 MPa to 20 MPa. When the stress on MD and TD is greater than 20 MPa, the rigidity becomes too high, thus reducing the pick-up capability of the semiconductor device and sometimes damaging the semiconductor device; when the stress on MD and TD is less than 5 MPa, the rigidity becomes low, thus sometimes making it difficult to unwind the substrate during the manufacturing process of the substrate film, and reducing the coating properties of the adhesive.

[0044] That is, since the stress (at 25% elongation) on MD and TD is between 5MPa and 20MPa, it is possible to provide a substrate film with excellent rigidity that can be unwound during the substrate film manufacturing process.

[0045] It should be noted that the stress on MD and TD (at 25% elongation) is preferably 6MPa to 15MPa, and more preferably 7MPa to 13MPa.

[0046] The substrate film of this embodiment does not have a yield point during the elongation process from 0% to 100% at a stretching speed of 300 mm / min. Therefore, a substrate film with excellent elongation uniformity can be provided.

[0047] In this embodiment, the mass ratio of 1-butene homopolymer to low-density polyethylene in the substrate film is preferably within the range of 10:90 to 70:30. By setting the mass ratio of 1-butene homopolymer to low-density polyethylene within this range, necking during substrate film forming can be prevented, resulting in more uniform expansion. Furthermore, the substrate can be unwound during the substrate film manufacturing process. This also prevents adhesion during substrate film winding and thickness variations caused by tensile resonance during substrate film forming. Therefore, a substrate film with excellent elongation uniformity, rigidity, and processing stability can be provided.

[0048] From the viewpoint of further improving the elongation uniformity of the substrate film, in this embodiment, the ratio of stress (at 40% elongation) to stress (at 20% elongation) on both the MD and TD (i.e., the elongation of the substrate film) is preferably 1 to 2, more preferably 1.05 to 1.8, and even more preferably 1.1 to 1.7. When the elongation of the substrate film is greater than 2, the excessive stress increases, and it is sometimes difficult to maintain the expansion ring. When the elongation of the substrate film is less than 1, necking may occur, making it difficult to achieve uniform expansion.

[0049] From the viewpoint of excellent homogeneity of the substrate film during expansion and suppression of relaxation, the ratio of stress on MD (at 25% elongation) to stress on TD (at 25% elongation) (i.e., the stress ratio of the substrate film at 25% elongation) is preferably 0.8 to 1.3, more preferably 0.85 to 1.15, and even more preferably 0.9 to 1.1.

[0050] It should be noted that the "stress" mentioned above refers to the stress measured in accordance with JIS K7161-2:2014.

[0051] The thickness of the substrate film 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 workability is improved; if the thickness is 300 μm or less, the flexibility (expansion) is improved. It should be noted that, in the case of substrate films for wafers, the thickness of the substrate film is preferably 50 μm to 150 μm, and more preferably 70 μm to 100 μm.

[0052] <Manufacturing Method>

[0053] The substrate film of this embodiment is manufactured by the following method: using a homopolymer containing the above-mentioned 1-butene and a resin material of low-density polyethylene with a density of 0.93 g / cm3 or less, the resin material is extruded at a specified temperature using, for example, an extruder equipped with a T-die. It should be noted that the substrate film of this embodiment can also be manufactured by known calendering or blow molding methods.

[0054] (Second Implementation)

[0055] The substrate film of this embodiment is a laminate composed of at least one intermediate layer and surface layers laminated on both sides of the intermediate layer, wherein the intermediate layer contains the homopolymer of 1-butene.

[0056] As a substrate film having this multilayer structure, for example, the substrate film 1 shown in FIG1 can be used as an example. The substrate film 1 is composed of an intermediate layer 2 and a surface layer 3 stacked on both sides of the intermediate layer 2, and has a three-layer structure stacked in the order of surface layer / intermediate layer / surface layer.

[0057] As a surface layer, examples include the surface layer containing 1-butene homopolymer and the surface layer containing polypropylene homopolymer described in the first embodiment above.

[0058] <Homopolymer of Polypropylene>

[0059] The homopolymer of polypropylene is homopolymer formed by polymerizing propylene alone. This homopolymer of polypropylene has high stereoregularity and high crystallinity, which contributes to its high melting point, resulting in excellent heat resistance. Due to its high crystallinity, it has high rigidity, but by mixing it with the aforementioned linear low-density polyethylene, it can achieve flexibility, which contributes to the spreadability of the substrate film.

[0060] As an intermediate layer, for example, an intermediate layer containing the above-mentioned homopolymer of 1-butene and an olefin-based elastomer can be used.

[0061] <Olefin-based elastomers>

[0062] Olefin elastomers are formed from olefin materials that conform to the definition of elastomers in JIS K 6200. More specifically, materials formed from copolymers of amorphous or low-crystallinity α-olefins are equivalent to olefin-based elastomers, materials with polyethylene as the main component are called ethylene-based elastomers, and materials with polypropylene as the main component are called propylene-based elastomers. For example, as an ethylene-based elastomer, there is the trade name "TAFMER (registered trademark)" manufactured by Mitsui Chemicals Co., Ltd., and as a propylene-based elastomer, there is the trade name "Vistamaxx (registered trademark)" manufactured by Exxon Mobil Co., Ltd.

[0063] It should be noted that the density of olefin elastomers is preferably 0.850~0.900 g / cm3, and more preferably 0.860~0.890 g / cm3.

[0064] From a processability and cost perspective, the preferred mass ratio of 1-butene homopolymer to olefin elastomer in the intermediate layer is in the range of 60:40 to 90:10.

[0065] <Substrate Film>

[0066] In this embodiment, the stress (at 25% elongation) on the substrate film in the MD and TD is between 5 MPa and 20 MPa. When the stress on the MD and TD is greater than 20 MPa, the rigidity becomes too high, thus reducing the pick-up capability of the semiconductor device and sometimes damaging the semiconductor device; when the stress on the MD and TD is less than 5 MPa, the rigidity becomes low, thus sometimes making it difficult to unwind the substrate during the manufacturing process of the substrate film, and reducing the coating properties of the adhesive.

[0067] That is, since the stress (at 25% elongation) on MD and TD is between 5MPa and 20MPa, it is possible to provide a substrate film with excellent rigidity that can be unwound during the substrate film manufacturing process.

[0068] The substrate film of this embodiment does not have a yield point during the elongation process from 0% to 100% at a stretching speed of 300 mm / min. Therefore, a substrate film with excellent elongation uniformity can be provided.

[0069] Similar to the substrate film of the first embodiment described above, from the viewpoint of further improving the elongation uniformity of the substrate film, the ratio of stress (at 40% elongation) to stress (at 20% elongation) (i.e., the elongation rate of the substrate film) in MD and TD is preferably 1 to 2, more preferably 1.05 to 1.8, and even more preferably 1.1 to 1.7.

[0070] Similar to the substrate film of the first embodiment described above, from the viewpoint of suppressing relaxation by utilizing the homogeneity of the substrate film during expansion, the ratio of the stress on MD (at 25% elongation) to the stress on TD (at 25% elongation) (i.e., the stress ratio of the substrate film at 25% elongation) is preferably 0.8 or more and 1.3 or less, more preferably 0.85 or more and 1.15 or less, and even more preferably 0.9 or more and 1.1 or less.

[0071] Similar to the substrate film in the first embodiment described above, the mass ratio of 1-butene homopolymer to low-density polyethylene in the substrate film forming the surface layer is preferably in the range of 10:90 to 70:30.

[0072] The thickness of the substrate film with a multilayer structure in this embodiment is the same as in the first embodiment described above, preferably 50~300μm, and more preferably 80~150μm. It should be noted that, in the case of a substrate film for wafers, the thickness of the substrate film is preferably 50μm~150μm, and more preferably 70μm~100μm.

[0073] For example, in the case of a substrate film having a three-layer structure with layers stacked in the order of surface layer / intermediate layer / surface layer, the thickness of the surface layer is not particularly limited, but is preferably 5 to 15 μm, more preferably 8 to 10 μm. The thickness of the intermediate 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 substrate film having a three-layer structure with layers stacked in the order of surface layer / intermediate layer / surface layer, from the viewpoint of processability and low cost, the ratio of the intermediate layer to the entire substrate film is preferably 40-95%, more preferably 50-90%.

[0075] <Manufacturing Method>

[0076] For example, in the case of manufacturing a substrate film having a three-layer structure with layers stacked in the order of surface layer / intermediate layer / surface layer, firstly, a resin material for forming the surface layer and a resin material for forming the intermediate layer are prepared.

[0077] Next, using an extruder equipped with a T-die, the surface layer forming resin material and the intermediate layer forming resin material are simultaneously extruded at a specified temperature to form a multilayer substrate film of this embodiment. This substrate film is a laminate consisting of an intermediate layer and surface layers laminated on both sides of the intermediate layer. It should be noted that the substrate film of this embodiment can also be manufactured by known calendering or blow molding methods.

[0078] <Other Implementation Methods>

[0079] Various additives can be included in the substrate film of the present invention. As additives, well-known additives commonly used in semiconductor tape manufacturing can be used, such as crosslinking aids, antistatic agents, heat stabilizers, antioxidants, ultraviolet absorbers, lubricants, anti-adhesion agents, and colorants. It should be noted that these additives can be used individually or in combination with two or more.

[0080] As a crosslinking aid, examples include triallyl isocyanurate. When the substrate film contains a crosslinking aid, the content of the crosslinking aid in the substrate film is preferably 0.05 parts to 5 parts by mass relative to 100 parts by mass of the resin forming the substrate film, and more preferably 1 part to 3 parts by mass.

[0081] In the second embodiment described above, a substrate film with a three-layer structure having layers stacked in the order of surface layer / intermediate layer / surface layer was used as an example. However, the substrate film with a multi-layer structure of the present invention is not limited to a three-layer structure. For example, it may also be a substrate film with a five-layer structure having layers stacked in the order of surface layer / intermediate layer / intermediate layer / intermediate layer / surface layer.

[0082] (Example)

[0083] The present invention will now be described with reference to the embodiments. It should be noted that the present invention is not limited to these embodiments, and modifications and alterations can be made to these embodiments according to the spirit of the present invention, and such modifications and alterations are also included within the scope of the present invention.

[0084] The materials used in the fabrication of the substrate film are shown below.

[0085] (1) LLDPE-1: linear low-density polyethylene, melting point: 120℃, density: 0.913g / cm3, MFR: 2.0g / 10min

[0086] (2) LLDPE-2: linear low-density polyethylene, melting point: 108℃, density: 0.921g / cm3, MFR: 2.5g / 10min

[0087] (3) LLDPE-3: linear low-density polyethylene, melting point: 93℃, density: 0.903g / cm3, MFR: 2.0g / 10min

[0088] (4) LLDPE-4: linear low-density polyethylene, melting point: 124℃, density: 0.936g / cm3, MFR: 2.0g / 10min

[0089] (5) LLDPE-5: linear low-density polyethylene, density: 0.923 g / cm3, MFR: 0.5 g / 10 min (manufactured by Priam Polymer, trade name: ULTZEX (registered trademark) 2005HC)

[0090] (6) LDPE-1: Low-density polyethylene, melting point: 108℃, density: 0.918g / cm3, MFR: 7.5g / 10min (manufactured by Ube-Maruzen Polyethylene Company, trade name: UBE polyethylene L719)

[0091] (7) LDPE-2: Low-density polyethylene, melting point: 110℃, density: 0.922g / cm3, MFR: 5.0g / 10min (manufactured by Ube-Maruzen Polyethylene Company, trade name: UBE POLYETHYLENE F522N)

[0092] (8) PP elastomer 1: Acrylic elastomer, density: 0.889 g / cm3, MFR: 8.0 g / 10 min (230℃), polyethylene content 4% (manufactured by Exxon Corporation, trade name: Vistamaxx (registered trademark) 3588FL)

[0093] (9) PP elastomer 2: Propylene elastomer, density: 0.862 g / cm3, MFR: 3.0 g / 10 min (230℃), polyethylene content: 16% (manufactured by Exxon Corporation, trade name: Vistamaxx (registered trademark) 6102FL)

[0094] (10) PP elastomer 3: Acrylic elastomer, melting point: 160℃, density: 0.868g / cm3, MFR: 6.0g / 10min (230℃)

[0095] (11) Amorphous polyolefin + crystalline polypropylene (1-butene·propylene copolymer: crystalline polypropylene = 50:50): density: 0.880 g / cm3, MFR: 11.7 g / 10 min (manufactured by Daihatsu Seika Co., Ltd., trade name: PERICON CAP350S)

[0096] (12) Homopolymer of 1-Bu: 1-Butene, melting point: 128℃, density: 0.920 g / cm3, MFR: 0.5 g / 10 min

[0097] (13) PE elastomer: ethylene-based elastomer, melting point: below 50℃, density: 0.864g / cm3, MFR: 6.7g / 10min (230℃)

[0098] (14) h-PP: Homopolymer of polypropylene, melting point: 163℃, density: 0.900g / cm3, MFR: 0.5g / 10min

[0099] (Example 1)

[0100] <Fabrication of Substrate Film>

[0101] First, the materials shown in Table 1 were mixed to prepare the resin material of Example 1 having the composition (parts by mass) shown in Table 1. Next, the resin material was extruded using three three-layer co-extruders with a T-die at a die temperature of 180°C to 200°C and a cooling roller temperature of 40°C, thereby obtaining a substrate film with the thickness shown in Table 1.

[0102] <Evaluation of the existence of the surrender point>

[0103] Using the prepared substrate film, a measurement sample was obtained according to JIS K7161-2:2014. Next, the obtained measurement sample was placed on a tensile testing machine (Shimadzu Corporation, product name: AG-5000A) with a clamping distance of 40 mm, and a tensile test was conducted at a tensile speed of 300 mm / min in an environment of 23°C and 40% relative humidity, according to JIS K7161-2:2014.

[0104] Then, in the SS curves (stress-strain curves) of MD and TD, cases where no yielding point was identified during elongation from 0% to 100% (no necking occurred, and uniform expansion was achieved) were marked as 0, and cases where a yielding point was identified (necking occurred, and uniform expansion was not achieved) were marked as ×. The results are shown in Table 1.

[0105] It should be noted that the S-S curves (stress-strain curves) of the MD and TD of the base film of this embodiment are shown in FIGS. 2 to 3. As shown in FIGS. 2 to 3, it can be seen that in the S-S curves (stress-strain curves) of the MD and TD, there is no yield point during the elongation process where the elongation rate ranges from 0% to 100%.

[0106] <Measurement of Stress on MD and TD>

[0107] Using the fabricated base film, measurement samples were obtained in accordance with JIS K7161-2:2014. Then, the obtained measurement samples were set on a tensile testing machine (manufactured by Shimadzu Corporation, product name: AG-5000A) with a distance between the clamps of 40 mm, and a tensile test was conducted in an environment of 23°C and a relative humidity of 40% at a tensile speed of 300 mm / min in accordance with JIS K7161-2:2014.

[0108] Then, the stress at 25% elongation (25% stress) on the MD and TD of the base film was measured, and at the same time, the ratio of the stress on the MD (at 25% elongation) to the stress on the TD (at 25% elongation) (i.e., the stress ratio of the base film at 25% elongation) was calculated. The above results are shown in Table 1.

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

[0110] <Rigidity Evaluation>

[0111] The fabricated base film was used to evaluate the rigidity. More specifically, in the manufacturing process of the base film, when the base material can be unrolled smoothly, it is marked as ○ (the rigidity of the base film is excellent), while in the manufacturing process of the base film, when the unrolling of the base material is unstable, it is marked as × (the rigidity of the base film is poor). The above results are shown in Table 1.

[0112] <Processing Stability Evaluation>

[0113] Processing stability was evaluated using pre-fabricated substrate films. More specifically, cases where the substrate film could be suppressed from sticking to the conveyor rollers during transport, prevent sticking during winding, and minimize thickness variations caused by tensile resonance during substrate film forming were denoted as 0 (excellent processing stability of the substrate film). Cases where the substrate film stuck to the conveyor rollers during transport, transport and winding were difficult, or thickness variations caused by tensile resonance during substrate film forming were denoted as × (lack of processing stability of the substrate film). The results are shown in Table 1.

[0114] (Examples 2-9, Comparative Examples 1-3)

[0115] Except for changing the composition of the resin components to the compositions (parts by mass) shown in Tables 1 and 3, a substrate film with the thicknesses shown in Tables 1 and 3 was prepared in the same manner as in Example 1 above.

[0116] Then, similar to Example 1 above, the existence of the yield point, stress on the MD and TD were evaluated, rigidity was evaluated, and processing stability was evaluated. The results are shown in Tables 1 and 3.

[0117] (Examples 10-15, Comparative Examples 4-8)

[0118] First, in each embodiment and comparative example, the materials shown in Tables 2 and 4 were mixed to prepare a surface layer forming resin material and an intermediate layer forming resin material having the compositions (parts by mass) shown in Tables 2 and 4.

[0119] Next, using three co-extrusion presses equipped with T-die for three layers, the resin material for forming the surface layer and the resin material for forming the intermediate layer are simultaneously extruded at 180°C to 200°C and the temperature of the cooling roller is 40°C, thereby obtaining a substrate film with the thicknesses shown in Tables 2 and 4 (i.e., the ratio of the intermediate layer to the entire substrate film is 80%) and a three-layer structure with the surface layer / intermediate layer / surface layer stacked sequentially.

[0120] Then, similar to Example 1 above, the existence of yield points, stress on MD and TD, rigidity, and processing stability were evaluated. The results are shown in Tables 2 and 4.

[0121] It should be noted that the MD and TD SS curves (stress-strain curves) of the substrate film of Example 10 are shown in Figures 4 and 5. As shown in Figures 4 and 5, it can be seen that in the MD and TD SS curves (stress-strain curves), there is no yielding point during the elongation process from 0% to 100%. Table 3

[0122] As shown in Tables 1 and 2, it can be seen that the substrate films in Examples 1 to 15 contain at least a homopolymer of 1-butene. Under the condition of a stretching speed of 300 mm / min, there is no yielding point during the elongation process from 0% to 100%, and the stress (at 25% elongation) is more than 5 MPa and less than 20 MPa. Therefore, the elongation uniformity is excellent, and the rigidity and processing stability are also excellent.

[0123] On the other hand, as shown in Table 3, it can be seen that in the substrate film of Comparative Example 1, due to the excessive addition of homopolymer of crystalline 1-butene, a yield point was identified, and on TD, the ratio of stress (at 40% elongation) to stress (at 20% elongation) was less than 1, lacking elongation uniformity.

[0124] As shown in Table 3, it can be seen that in the substrate film of Comparative Example 2, since there is no homopolymer containing 1-butene, the yield point was confirmed, and the elongation uniformity was lacking. In addition, the processing stability was also lacking.

[0125] As shown in Table 3, it can be seen that in the substrate film of Comparative Example 3, since high-density and highly crystalline linear low-density polyethylene was used, a yield point was identified, and on TD, the ratio of stress (at 40% elongation) to stress (at 20% elongation) was less than 1, lacking elongation uniformity.

[0126] As shown in Table 4, it can be seen that in the substrate film of Comparative Example 4, since there is no 1-butene homopolymer, a yield point was identified, resulting in a lack of elongation uniformity. Since the ratio of stress on MD (at 25% elongation) to stress on TD (at 25% elongation) is greater than 1.3, homogeneity is also lacking. Because a low-viscosity butene copolymer was used, the thickness variation caused by tensile resonance during substrate film forming is increased, resulting in a lack of processing stability.

[0127] As shown in Table 4, it can be seen that the substrate film of Comparative Example 5 does not contain a homopolymer of 1-butene, and the stress on TD (at 25% elongation) is less than 5 MPa. Therefore, during the manufacturing process of the substrate film, the unwinding of the substrate becomes unstable and lacks rigidity.

[0128] As shown in Table 4, it can be seen that in the substrate film of Comparative Example 6, which is a homopolymer without 1-butene, the ratio of stress (at 40% elongation) to stress (at 20% elongation) on MD and TD is less than 1, thus confirming a yield point and a lack of elongation uniformity. Since the stress (at 25% elongation) on MD and TD is less than 5 MPa, the unwinding of the substrate becomes unstable and lacks rigidity during the substrate film manufacturing process. Because the film surface has high adhesion, it can be seen that the substrate film adheres to the conveyor rollers during transport, making the transport and winding of the substrate film difficult, indicating a lack of processing stability.

[0129] As shown in Table 4, it can be seen that in the substrate film of Comparative Example 7, the stress on TD (at 25% elongation) is less than 5 MPa. Therefore, during the manufacturing process of the substrate film, the substrate unwinding becomes unstable and lacks rigidity.

[0130] As shown in Table 4, it can be seen that in the substrate film of Comparative Example 8, the ratio of stress on MD (at 25% elongation) to stress on TD (at 25% elongation) is greater than 1.3, thus lacking homogeneity. On TD, the ratio of stress (at 40% elongation) to stress (at 20% elongation) is less than 1, confirming the yield point, indicating a lack of elongation uniformity.

[0131] -Industry availability-

[0132] As described above, the present invention is applicable to substrate films for semiconductor manufacturing tapes.

[0133] 1: Substrate film 2: Intermediate layer 3: Surface layer

Claims

1. A substrate film for semiconductor manufacturing tape, characterized in that it contains at least a homopolymer of 1-butene and linear low-density polyethylene with a density of 0.93 g / cm3 or less; wherein the mass ratio of the aforementioned homopolymer of 1-butene to linear low-density polyethylene is 10:90 to 70:30; under the conditions of a thickness of 80 μm and a tensile speed of 300 mm / min, the substrate film does not have a yield point during the elongation process from 0% to 100%; and under the condition of a thickness of 80 μm, the stress (at 25% elongation) is more than 5 MPa and less than 20 MPa.

2. The substrate film for semiconductor manufacturing tape as described in claim 1, wherein, under a thickness of 80 μm, the ratio of stress (at 40% elongation) to stress (at 20% elongation) is 1 to 2.

3. The substrate film for semiconductor manufacturing tape as described in claim 1 or 2, wherein, under the condition of a thickness of 80 μm, the ratio of the stress (at 25% elongation) in the mechanical axis (length) direction MD of the substrate film to the stress (at 25% elongation) in the direction orthogonal to MD is 0.8 or more and 1.3 or less.

4. A substrate film for semiconductor manufacturing tape, characterized in that it comprises at least an intermediate layer containing a homopolymer of 1-butene; and a surface layer laminated on both sides of the intermediate layer; the surface layer comprises the homopolymer of 1-butene and linear low-density polyethylene with a density of 0.930 g / cm3 or less, wherein the mass ratio of the homopolymer of 1-butene to the linear low-density polyethylene is 40:60; under the conditions of an intermediate layer thickness of 64 μm, a surface layer thickness of 8 μm, and a tensile speed of 300 mm / min, the substrate film does not have a yield point during elongation from 0% to 100%; and under the conditions of an intermediate layer thickness of 64 μm and a surface layer thickness of 8 μm, the stress (at 25% elongation) is 5 MPa or more and 20 MPa or less.

5. The substrate film for semiconductor manufacturing tape as described in claim 4, wherein, under the conditions that the thickness of the aforementioned intermediate layer is 64 μm and the thickness of the aforementioned surface layer is 8 μm, the ratio of stress (at 40% elongation) to stress (at 20% elongation) is more than 1 and less than 2.

6. The substrate film for semiconductor manufacturing tape as described in claim 4 or 5, wherein, under the condition that the thickness of the aforementioned intermediate layer is 64 μm and the thickness of the aforementioned surface layer is 8 μm, the ratio of the stress (at 25% elongation) in the mechanical axis (length) direction MD of the substrate film to the stress (at 25% elongation) in the direction orthogonal to MD is 0.8 or more and 1.3 or less.

7. A substrate film for semiconductor manufacturing tape, characterized in that it comprises at least a homopolymer of 1-butene and a linear low-density polyethylene with a density of 0.93 g / cm3 or less, wherein the mass ratio of the homopolymer of 1-butene to the linear low-density polyethylene is 40:60, an intermediate layer, and surface layers laminated on both sides of the intermediate layer; under the conditions that the thickness of the intermediate layer is 64 μm, the thickness of the surface layer is 8 μm, and the tensile speed is 300 mm / min, the substrate film does not have a yield point during elongation from 0% to 100%; and under the conditions that the thickness of the intermediate layer is 64 μm and the thickness of the surface layer is 8 μm, the stress (at 25% elongation) is 5 MPa or more and 20 MPa or less.

8. The substrate film for semiconductor manufacturing tape as described in claim 7, wherein, under the conditions that the thickness of the aforementioned intermediate layer is 64 μm and the thickness of the aforementioned surface layer is 8 μm, the ratio of stress (at 40% elongation) to stress (at 20% elongation) is more than 1 and less than 2.

9. The substrate film for semiconductor manufacturing tape as described in claim 7 or 8, wherein, under the condition that the thickness of the aforementioned intermediate layer is 64 μm and the thickness of the aforementioned surface layer is 8 μm, the ratio of the stress (at 25% elongation) in the mechanical axis (length) direction MD of the substrate film to the stress (at 25% elongation) in the direction orthogonal to MD is 0.8 or more and 1.3 or less.

Images