Base material film

Abstract

This base material film is for a tape for use in a semiconductor manufacturing process. The base material film comprises a base layer and an anti-static layer. The anti-static layer is laminated on the base layer. On the surface of the anti-static layer side, the difference between the maximum value of the arithmetic average roughness (Ra) and the minimum value of the arithmetic average roughness (Ra) is 1.1 μm or less.

Description

Base film

[0001] The present invention relates to a substrate film, and more particularly to a substrate film for tapes used in the semiconductor manufacturing process.

[0002] In the manufacturing process of semiconductor wafers and semiconductor packages, various tapes having a pressure-sensitive adhesive layer laminated on at least one surface of a base film are used. Examples of tapes include dicing tape and back-grinding tape. Dicing tape is applied to a semiconductor wafer in the dicing process, which divides the semiconductor wafer into multiple semiconductor chips. Back-grinding tape is applied to the patterned surface of a semiconductor wafer in the grinding process, which thins the semiconductor wafer.

[0003] Japanese Patent Laid-Open Publication No. 2018-125521 (Patent Document 1) discloses a substrate film used in a dicing tape. Japanese Patent Laid-Open Publication No. 2020-088231 (Patent Document 2) discloses a substrate film used in a backgrinding tape.

[0004] JP 2018-125521 A JP 2020-088231 A

[0005] In the case of substrate films for tapes used in semiconductor manufacturing processes (e.g., dicing tapes or backgrinding tapes), the surface resistance value may vary greatly within the plane. Substrate films with a large variation in the surface resistance value within the plane may not meet quality standards and may be considered defective. The above-mentioned Patent Documents 1 and 2 do not disclose a means for solving this problem.

[0006] The present invention has been made to solve such problems, and an object of the present invention is to provide a substrate film having a relatively small in-plane variation in surface resistance.

[0007] The substrate film according to the present invention is a substrate film for a tape used in a semiconductor manufacturing process. The substrate film includes a base layer and an antistatic layer. The antistatic layer is laminated on the base layer. On the surface facing the antistatic layer, the difference between the maximum arithmetic mean roughness (Ra) and the minimum arithmetic mean roughness (Ra) is 1.1 μm or less.

[0008] The present inventors have found that there is a correlation between the surface roughness of a substrate film and its surface resistance. With this substrate film, the difference between the maximum and minimum arithmetic mean roughness (Ra) on the surface of the antistatic layer side is 1.1 μm or less, and the in-plane variation in surface roughness of the substrate film is relatively small, thereby suppressing the in-plane variation in surface resistance.

[0009] On the surface of the substrate film facing the antistatic layer, the difference between the maximum value of the arithmetic mean roughness (Ra) and the minimum value of the arithmetic mean roughness (Ra) may be less than 0.30 μm.

[0010] With this substrate film, the difference between the maximum value of the arithmetic mean roughness (Ra) and the minimum value of the arithmetic mean roughness (Ra) on the surface on the antistatic layer side is 0.30 μm or less, and the variation in surface roughness within the plane of the substrate film is smaller, so that the variation in surface resistivity within the plane can be further suppressed.

[0011] In the substrate film, the maximum value of the arithmetic mean roughness (Ra) on the surface on the antistatic layer side may be divided by the thickness of the antistatic layer, and the result may be less than 1.0.

[0012] The inventors have found that when the maximum value of the arithmetic mean roughness (Ra) on the surface on the antistatic layer side is divided by the thickness of the antistatic layer and the result is less than 1.0, the surface resistance is within a desired range (for example, 10 ９ Ω / □ or more, 10 １０ With this substrate film, the maximum arithmetic mean roughness (Ra) on the surface on the antistatic layer side divided by the thickness of the antistatic layer is less than 1.0, so that the surface resistance can be kept within a desired range.

[0013] In the substrate film, the maximum value of the arithmetic mean roughness (Ra) on the surface on the antistatic layer side may be divided by the thickness of the antistatic layer to give a value of less than 0.16.

[0014] In this substrate film, the maximum value of the arithmetic mean roughness (Ra) on the surface on the antistatic layer side divided by the thickness of the antistatic layer is less than 0.16, so that the surface resistance is within a desired range (for example, 10 ９ Ω / □ or more, 8.9×10 ９ It can be kept within the range of Ω / □ or less.

[0015] In the above substrate film, the surface resistance value is 10 ９ Ω / □ or more, 10 １０ It may be less than Ω / □.

[0016] According to the present invention, it is possible to provide a substrate film having a relatively small in-plane variation in surface resistance.

[0017] 1 is a diagram schematically illustrating a cross section of a substrate film. FIG. 2 is a diagram schematically illustrating a configuration of a substrate film manufacturing apparatus.

[0018] An embodiment according to one aspect of the present invention (hereinafter also referred to as "the present embodiment") will be described in detail below with reference to the drawings. Note that identical or corresponding parts in the drawings are designated by the same reference numerals, and their description will not be repeated. Furthermore, for ease of understanding, each drawing is drawn in a schematic manner with objects appropriately omitted or exaggerated.

[0019] [1. Structure of the Substrate Film] Fig. 1 is a diagram schematically illustrating a cross section of a substrate film 10 according to the present embodiment. As shown in Fig. 1, the substrate film 10 includes a base layer 20 and an antistatic layer 30 laminated on the base layer 20. In the substrate film 10, since the antistatic layer 30 is laminated on the base layer 20, static electricity is less likely to be generated on the surface on the antistatic layer 30 side. Therefore, the substrate film 10 is suitable for use as a substrate film for tapes used in semiconductor manufacturing processes (e.g., dicing tape or back-grinding tape). Each layer constituting the substrate film 10 will be described in detail below.

[0020] <1-1. Antistatic Layer> The antistatic layer 30 is composed of a resin composition containing at least a thermoplastic resin, a polymeric antistatic agent, and a thermoplastic elastomer. That is, this resin composition may contain, for example, a thermoplastic resin and a polymeric antistatic agent, but may not contain a thermoplastic elastomer, or may contain all of a thermoplastic resin, a polymeric antistatic agent, and a thermoplastic elastomer. Each component will be described below.

[0021] (1-1-1. Thermoplastic Resin) The thermoplastic resin contained in the antistatic layer 30 is not particularly limited, but is preferably selected from, for example, ethylene-based resins or propylene-based resins. Examples of ethylene-based resins include polyethylene, branched low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-methyl acrylate copolymer (EMMA), ethylene-methacrylic acid copolymer (EMAA), and ionomer resins. Of these, LDPE and EMMA are preferred.

[0022] Examples of propylene-based resins include propylene-based copolymers and propylene-based terpolymers, which contain propylene as the main component and an α-olefin as a copolymerization component. Among these, propylene-based terpolymers are preferred. Examples of the α-olefin as a copolymerization component include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene. The proportion of the α-olefin as a copolymerization component is preferably 1 to 10 mol %. Furthermore, the propylene-based resin may be a mixture of different propylene-α-olefin random copolymers.

[0023] The resin composition constituting the antistatic layer 30 preferably contains 30% by weight or more and 80% by weight or less of a thermoplastic resin, more preferably 35% by weight or more and 75% by weight or less, and even more preferably 40% by weight or more and 70% by weight or less, relative to 100% by weight of the entire layer.

[0024] (1-1-2. Polymer-Type Antistatic Agent) The polymer-type antistatic agent adjusts the surface resistance of the antistatic layer 30, thereby imparting to the base film 10 the function of suppressing static buildup and preventing direct discharge. Examples of polymer-type antistatic agents include polyether ester amide (PEEA) and hydrophilic olefin block copolymer. The resin composition constituting the antistatic layer 30 can contain either of these.

[0025] The resin composition constituting the antistatic layer 30 preferably contains one of the above polymer antistatic agents in an amount of 20 wt % or more and 40 wt % or less, more preferably 25 wt % or more and 35 wt % or less, and even more preferably 27 wt % or more and 33 wt % or less, based on 100 wt % of the total resin composition. By setting the content of one polymer antistatic agent to the above lower limit or more, sufficient antistatic function can be imparted to the antistatic layer 30. On the other hand, by setting the content of one polymer antistatic agent to the above upper limit or less, deterioration of the appearance of the substrate film 10 due to aggregation of the polymer antistatic agent and variation in surface resistance value depending on the position can be suppressed.

[0026] (1-1-3. Thermoplastic Elastomer) Examples of thermoplastic elastomers include hydrogenated styrene-based elastomers and modified products thereof. Thermoplastic elastomers improve the dispersibility of polymeric antistatic agents in the resin composition and promote the formation of conductive circuits by the polymeric antistatic agents in the antistatic layer 30. This reduces the variation in surface resistance depending on the position in the antistatic layer 30, improving the appearance. Note that poor appearance of the antistatic layer 30 refers to defects that impair the transparency of the base film 10, such as the appearance of streaky opaque marks or cloudiness that appears milky white. Such defects are thought to occur due to uneven distribution of components in the resin composition.

[0027] Transparency of the base film 10 is required for the following reasons. For example, when semiconductor processing equipment aligns semiconductor wafers using image processing and a light source, if the semiconductor processing tape has a visual defect, it may interfere with proper control of the processing equipment. Also, in a dicing process, for example, a laser is irradiated onto the semiconductor wafer through the dicing tape attached to the semiconductor wafer. In such a case, if the semiconductor processing tape has a visual defect, unevenness will occur in the amount of laser transmission through the dicing tape, which may result in poor dicing.

[0028] The resin composition constituting the antistatic layer 30 preferably contains 5 wt % to 40 wt % of the thermoplastic elastomer, more preferably 10 wt % to 35 wt % and even more preferably 15 wt % to 33 wt %, based on 100 wt % of the entire layer. By setting the content of the thermoplastic elastomer at or above the lower limit, a sufficient compatibilizing effect can be achieved. On the other hand, by setting the content of the thermoplastic elastomer at or below the upper limit, excessive promotion of compatibilization and the inhibition of the formation of a conductive circuit by the polymeric antistatic agent can be avoided.

[0029] The thickness of the antistatic layer 30 is preferably 2 μm or more and 20 μm or less, more preferably 3 μm or more and 15 μm or less, and even more preferably 4 μm or more and 12 μm or less. By making the thickness of the antistatic layer 30 equal to or more than the above-mentioned lower limit, a sufficient antistatic function is imparted to the base film 10, while by making the thickness of the antistatic layer 30 equal to or less than the above-mentioned upper limit, the cost of the base film 10 is reduced.

[0030] <1-2. Base Layer> The base layer 20 is a layer containing a thermoplastic resin as a main component, and is a layer that is dominant in achieving room temperature expandability and uniform expandability, which will be described later. The base layer 20 may be composed of a single layer or multiple layers. In the substrate film 10 according to the present embodiment, the base layer 20 includes a core layer 21, two adhesive layers 22 (adhesive layers 22A and 22B), and two surface layers 23 (surface layers 23A and 23B). Each of the surface layers 23A and 23B constitutes a surface of the base layer 20. The adhesive layer 22A is laminated between the core layer 21 and the surface layer 23A, and the adhesive layer 22B is laminated between the core layer 21 and the surface layer 23B. The base layer 20 has a symmetrical structure with respect to the core layer 21, which suppresses curling.

[0031] The thickness of the base layer 20 is preferably 40 μm or more and 200 μm or less, more preferably 45 μm or more and 190 μm or less, and even more preferably 50 μm or more and 180 μm or less.

[0032] (1-2-1. Surface Layer) The surface layer 23 is a layer that constitutes the surface of the base layer 20. In the substrate film 10, the antistatic layer 30 is laminated on the surface layer 23B. The surface layer 23 contains, for example, a thermoplastic resin. The thermoplastic resin contained in the surface layer 23 may be the same as the thermoplastic resin contained in the antistatic layer 30. The surface layer 23 may contain, for example, an ethylene-based resin or a propylene-based resin described in the section on the antistatic layer 30. Of these, LDPE is preferred as the thermoplastic resin contained in the surface layer 23. For example, if the thermoplastic resin contained in the antistatic layer 30 and the thermoplastic resin contained in the surface layer 23 are the same, uneven flow rates during co-extrusion of the resin compositions that constitute these layers are suppressed, thereby suppressing adverse effects on the appearance of the substrate film 10. In this case, the compatibility between the layers is improved, thereby improving the adhesive strength between the layers.

[0033] The thickness of the surface layer 23 is preferably 5 μm or more and 40 μm or less, more preferably 8 μm or more and 35 μm or less, and even more preferably 10 μm or more and 30 μm or less.

[0034] (1-2-2. Adhesive Layer) The adhesive layer 22 is a layer for adhering the core layer 21 and the surface layer 23. The adhesive layer 22 is made of a resin composition containing, for example, the ethylene-based resin, propylene-based resin, or amorphous olefin-based resin described below in the section on the antistatic layer 30. The resin composition constituting the adhesive layer 22 may contain two or more of these resins.

[0035] Examples of amorphous olefin-based resins include amorphous polypropylene (also called flexible polypropylene) obtained by homopolymerizing propylene using a specific catalyst, and copolymers obtained by copolymerizing at least one of propylene and 1-butene with an α-olefin having 2 to 20 carbon atoms (excluding propylene and 1-butene) using a specific catalyst. The polymerization ratio of propylene or 1-butene is preferably 50% by weight or more, more preferably 60% by weight or more, even more preferably 70% by weight or more, particularly preferably 80% by weight or more, and most preferably 90% by weight or more.

[0036] A resin composition containing a mixture of LDPE and LLDPE is preferred as the resin composition constituting the adhesive layer 22. The LDPE and LLDPE used in the adhesive layer 22 may be the same as or different from the LDPE and LLDPE used in the surface layer 23, respectively.

[0037] The thickness of the adhesive layer 22 is preferably 2 μm or more and 20 μm or less, more preferably 3 μm or more and 15 μm or less, and even more preferably 4 μm or more and 12 μm or less.

[0038] (1-2-3. Core Layer) The core layer 21 is the thickest layer in the base film 10. The core layer 21 is made of a resin composition containing, for example, at least one of the ethylene-based resin and propylene-based resin described in the section on the antistatic layer 30 and the amorphous olefin-based resin described in the section on the adhesive layer 22.

[0039] The thickness of the core layer 21 is preferably 30 μm or more and 160 μm or less, more preferably 40 μm or more and 150 μm or less, and even more preferably 50 μm or more and 140 μm or less.

[0040] [2. Various Parameters Related to the Base Film] <2-1. Arithmetic Mean Roughness (Ra)> As described above, the base film 10 is used as a base material for tapes (e.g., dicing tapes or back-grinding tapes) used in semiconductor manufacturing processes. If the surface resistance value of the base film 10 varies greatly within its plane, the base film 10 may be deemed a defective product.

[0041] The present inventor(s) have found that there is a correlation between the surface roughness of the base film 10 and the surface resistance value of the base film 10. Specifically, the present inventor(s) have found that there is a tendency that as the surface roughness value of the base film 10 increases, the measured surface resistance value of the base film 10 increases, and that as the surface roughness value of the base film 10 decreases, the measured surface resistance value of the base film 10 decreases.

[0042] In the base film 10, the difference between the maximum value of the arithmetic mean roughness (Ra) and the minimum value of the arithmetic mean roughness (Ra) is 1.1 μm or less on the surface F1 facing the antistatic layer 30. According to the base film 10, the difference between the maximum value of the arithmetic mean roughness (Ra) and the minimum value of the arithmetic mean roughness (Ra) is 1.1 μm or less on the surface F1 facing the antistatic layer 30, and the in-plane variation in surface roughness of the base film 10 is relatively small, so that the in-plane variation in surface resistance can be suppressed.

[0043] Furthermore, it is preferable that the difference between the maximum value of the arithmetic mean roughness (Ra) and the minimum value of the arithmetic mean roughness (Ra) of the substrate film 10 is 0.30 μm or less on the surface F1 facing the antistatic layer 30. In this case, with the substrate film 10, the difference between the maximum value of the arithmetic mean roughness (Ra) and the minimum value of the arithmetic mean roughness (Ra) of the surface F1 facing the antistatic layer 30 is 0.30 μm or less, and the in-plane variation in surface roughness of the substrate film 10 is smaller, thereby further suppressing the in-plane variation in surface resistance.

[0044] The arithmetic mean roughness (Ra) is measured in accordance with JIS B 0601: 1994. For measuring the arithmetic mean roughness (Ra), for example, a Retrofit 1400D-3DF manufactured by Tokyo Seimitsu Co., Ltd. is used (for example, needle tip size: 5 μm, cutoff: 0.08 mm, length: 1.2 mm, T-SPEED: 0.03 mm / s).

[0045] <2-2. Surface Resistivity> The surface resistance of the substrate film 10 is, for example, 10 ９ Ω / □ or more, 10 １０ Ω / □ or less, and ９ Ω / □ or more, 8.9×10 ９ The surface resistance is preferably less than Ω / □. The surface resistance is measured in accordance with JIS K6911:1995. For example, a Hiresta UP MCP-450 model manufactured by Nitto Seiko Analytech Co., Ltd. is used to measure the surface resistance (for example, probe: UR100, measurement mode: surface resistance, applied voltage: 500 V, timer: 10 seconds).

[0046] <2-3. Result of Dividing Maximum Value of Arithmetic Average Roughness (Ra) by Thickness of Antistatic Layer> The present inventors have determined that when the result of dividing the maximum value of the arithmetic average roughness (Ra) on the surface on the antistatic layer 30 side by the thickness of the antistatic layer 30 is less than 1.0, the surface resistance of the substrate film 10 is within a desired range (for example, 10 ９ Ω / □ or more, 10 １０It was found that the surface resistance of the substrate film 10 falls within a desired range (less than Ω / □). In the substrate film 10, the maximum value of the arithmetic mean roughness (Ra) on the surface facing the antistatic layer 30 divided by the thickness of the antistatic layer 30 is less than 1.0. Therefore, with the substrate film 10, the maximum value of the arithmetic mean roughness (Ra) on the surface facing the antistatic layer 30 divided by the thickness of the antistatic layer 30 is less than 1.0, and therefore the surface resistance of the substrate film 10 can be kept within a desired range.

[0047] In addition, it is preferable that the result of dividing the maximum value of the arithmetic mean roughness (Ra) on the surface F1 of the base film 10 on the antistatic layer 30 side by the thickness of the antistatic layer 30 is less than 0.16. In this case, according to the base film 10, the result of dividing the maximum value of the arithmetic mean roughness (Ra) on the surface F1 on the antistatic layer 30 side by the thickness of the antistatic layer 30 is less than 0.16, and therefore the surface resistance value is within a desired range (for example, 10 ９ Ω / □ or more, 8.9×10 ９ It can be kept within the range of Ω / □ or less.

[0048] <2-4. Room-Temperature Expandability> The room-temperature expandability of the substrate film 10 is evaluated, for example, by the tensile elongation (%). Regarding the MD (Machine Direction) and TD (Transverse Direction) of the substrate film 10, a film sample processed to a width of 15 mm and a chuck distance of 40 mm is stretched at a stretching speed of 200 mm / min. The tensile elongation measured in both the MD and TD is preferably 100% or more. This is because a tensile elongation of less than 100% can cause tearing or wrinkling during expansion in the processing of semiconductor wafers, etc. The MD is the extrusion direction of the substrate film 10 and is also the longitudinal direction. The TD is the direction perpendicular to the MD.

[0049] <2-5. Uniform Expandability> The uniform expandability of the substrate film 10 is evaluated, for example, by the 25% modulus ratio (MD / TD). A film sample processed to a width of 15 mm and a chuck distance of 40 mm is stretched at a tension speed of 200 mm / min in the MD and TD of the substrate film 10 to obtain a stress-strain curve (SS curve). The ratio of the MD stress value at a tensile elongation of 25% to the TD stress value at a tensile elongation of 25% in the obtained SS curve is calculated and used as the modulus ratio (MD / TD). The modulus ratio (MD / TD) is preferably less than 1.5. If the modulus ratio (MD / TD) is less than 1.5, the uniform expansion of the semiconductor processing tape results in uniform spacing between individual semiconductor chips (kerf width), preventing the semiconductor chips from tilting and improving pickup properties. On the other hand, if the modulus ratio (MD / TD) is 1.5 or more, the kerf width becomes non-uniform, which may cause misalignment of the semiconductor chips, collisions between semiconductor chips, and damage due to these.

[0050] 2 is a diagram schematically illustrating the configuration of a manufacturing apparatus 50 for the base film 10. As shown in FIG. 2, the manufacturing apparatus 50 includes a T-die 500, casting rolls 510 and 520, and a take-up roll 530.

[0051] The T-die 500 is configured to heat and melt materials fed into six raw material feed sections (not shown) to produce molten materials and extrude them. The first feed section receives the material for the surface layer 23A, the second feed section receives the material for the adhesive layer 22A, and the third feed section receives the material for the core layer 21. The fourth feed section receives the material for the adhesive layer 22B, the fifth feed section receives the material for the surface layer 23B, and the sixth feed section receives the material for the antistatic layer 30.

[0052] The casting rolls 510 and 520 are configured to cool the extruded molten material and send it downstream. The surface roughness of the base film 10 is caused, for example, by the roughness of the surfaces of the casting rolls 510 and 520. The winding roll 530 is configured to pull and wind the molten material cooled by the casting rolls 510 and 520 at a predetermined speed. A roll of the base film 10 is produced through the manufacturing process in the manufacturing apparatus 50.

[0053] For example, the temperature of the casting roll 510 is 10° C. or higher and 80° C. or lower, and preferably 20° C. or higher and 60° C. or lower. Also, for example, the predetermined speed at which the molten material is pulled by the take-up roll 530 is 3 m / min. or higher and 30 m / min. or lower, and preferably 9 m / min. or higher and 25 m / min. or lower.

[0054] [4. Features] As described above, the substrate film 10 according to the present embodiment is a substrate film for a tape used in a semiconductor manufacturing process. The substrate film 10 includes a base layer 20 and an antistatic layer 30. The antistatic layer 30 is laminated on the base layer 20. On the surface facing the antistatic layer 30, the difference between the maximum and minimum arithmetic mean roughness (Ra) is 1.1 μm or less. With the substrate film 10, the difference between the maximum and minimum arithmetic mean roughness (Ra) on the surface facing the antistatic layer 30 is 1.1 μm or less, and the variation in surface roughness within the surface of the substrate film 10 is relatively small, thereby suppressing variation in surface resistance within the surface.

[0055] 5. Other Embodiments The concept of the above-described embodiment is not limited to the embodiment described above. Hereinafter, examples of other embodiments to which the concept of the above-described embodiment can be applied will be described.

[0056] <5-1> In the base film 10 according to the above embodiment, additives such as antistatic agents other than polymeric antistatic agents, antioxidants, heat stabilizers, ultraviolet absorbers, light stabilizers, lubricants, flame retardants, antibacterial agents, fluorescent brightening agents, colorants, and fillers may be added to the resin compositions constituting the core layer 21, the adhesive layer 22, the surface layer 23, and the antistatic layer 30, as long as the effects of the present invention are not impaired.

[0057] <5-2> In the above embodiment, the antistatic layer 30 is laminated on the base layer 20 by co-extrusion. However, the method for laminating the antistatic layer 30 on the base layer 20 is not limited to this. The antistatic layer 30 may be laminated on the base layer 20 by, for example, coating.

[0058] The above describes exemplary embodiments of the present invention. That is, the detailed description and the accompanying drawings are disclosed for the purpose of illustrative explanation. Therefore, some of the components described in the detailed description and the accompanying drawings may be non-essential components for solving the problems. Therefore, just because these non-essential components are described in the detailed description and the accompanying drawings, it should not be immediately recognized that these non-essential components are essential.

[0059] Furthermore, the above-described embodiments are merely illustrative of the present invention in all respects. Various improvements and modifications to the above-described embodiments are possible within the scope of the present invention. For example, at least a portion of the configuration of any of the embodiments may be combined with at least a portion of the configuration of any of the other embodiments. In other words, when implementing the present invention, specific configurations can be appropriately adopted depending on the embodiment.

[0060] Next, examples of the present invention will be described, but the present invention is not limited to the following examples.

[0061] [1. Examples and Comparative Examples] Substrate films were produced in Examples 1 to 9 and Comparative Examples 1 to 3. Each of the substrate films in Examples 1 to 9 and Comparative Examples 1 to 3 had a four-type, six-layer structure in which a surface layer / adhesive layer / core layer / adhesive layer / surface layer / antistatic layer were laminated in this order. The thermoplastic resins used in the base layers of the substrate films in Examples 1 to 9 and Comparative Examples 1 to 3 were LDPE, LDPE, LDPE, LDPE, PP, EVA, ionomer, LDPE, ionomer, PP, LDPE, and ionomer, respectively. The thermoplastic resins used in the antistatic layers of the substrate films of Examples 1 to 9 and Comparative Examples 1 to 3 were LDPE, LDPE, LDPE, LDPE, PP, EVA, ionomer, LDPE, ethylene-methacrylic acid copolymer, PP, LDPE, and ionomer, respectively, to which a hydrophilic olefin block copolymer antistatic resin was added in an amount of 30 wt % based on the total weight of the layer to exhibit antistatic properties. The thicknesses of the substrate films of Examples 1 to 9 and Comparative Examples 1 to 3 were 70 μm, 150 μm, 150 μm, 150 μm, 150 μm, 125 μm, 150 μm, 70 μm, 80 μm, 70 μm, 150 μm, and 100 μm, respectively.

[0062] [2. Measurement of Various Parameters] <2-1. Surface Roughness (Rz)> The ten-point average roughness (Rz) was measured in accordance with JIS B 0601:1994. A Tokyo Seimitsu Retrofit 1400D-3DF (needle tip size: 5 μm, cutoff: 0.08 mm, length: 1.2 mm, T-SPEED: 0.03 mm / s) was used to measure the ten-point average roughness (Rz). A substrate film 600 mm wide and 600 mm long was prepared, and the ten-point average roughness (Rz) was measured at 10 points at 60 mm intervals in the width direction starting from 30 mm from the end, and at 10 points in the length direction, for a total of 100 points.

[0063] <2-2. Surface roughness (Ra)> The arithmetic mean roughness (Ra) was measured in accordance with JIS B 0601:1994. A Retrofit 1400D-3DF manufactured by Tokyo Seimitsu Co., Ltd. was used to measure the arithmetic mean roughness (Ra) (needle tip size: 5 μm, cutoff: 0.08 mm, length: 1.2 mm, T-SPEED: 0.03 mm / s). A substrate film 600 mm wide and 600 mm long was prepared, and the arithmetic mean roughness (Ra) was measured at 10 points at 60 mm intervals in the width direction starting from 30 mm from the end, and at 10 points in the length direction, for a total of 100 points.

[0064] <2-3. Surface Resistivity> The surface resistance of the substrate film was measured in accordance with JIS K6911:1995. The surface resistance was measured using a Hiresta UP MCP-450 model manufactured by Nitto Seiko Analytech Co., Ltd. (probe: UR100, measurement mode: surface resistance, applied voltage: 500 V, timer: 10 seconds). A substrate film measuring 600 mm in width and 600 mm in length was prepared and left overnight in an environment with a temperature of 23±2°C and a humidity of 50±10%, and then the surface resistance was measured in the same environment at 10 points in the width direction at 60 mm intervals starting from a position 30 mm from the edge and at 10 points in the length direction, for a total of 100 points.

[0065] <2-4. Room-temperature expandability> The room-temperature expandability of the substrate film was evaluated by tensile elongation (%). A film sample processed to a width of 15 mm and a chuck distance of 40 mm was stretched at a stretching speed of 200 mm / min in the MD and TD of the substrate film, and the tensile elongation (%) was measured.

[0066] <2-5. Uniform Expandability> The uniform expandability of the substrate film was evaluated by the 25% modulus ratio (MD / TD). A film sample processed to a width of 15 mm and a chuck distance of 40 mm was stretched at a stretching speed of 200 mm / min to obtain a stress-strain curve (SS curve) for the MD and TD of the substrate film. The ratio of the MD stress value at a tensile elongation of 25% to the TD stress value at a tensile elongation of 25% was calculated from the obtained SS curve, and this was taken as the modulus ratio (MD / TD).

[0067] <2-6. Antistatic Layer Thickness> The thickness of the antistatic layer was measured by taking a cross-sectional photograph of the substrate film using a laser microscope VK-X100 manufactured by Keyence Corporation.

[0068] [3. Measurement Results] The measurement results for each item are shown in the following Table 1. In Table 1, "AS layer" refers to the antistatic layer.

[0069] As shown in Table 1, the expandability was good in each of the substrate films of Examples 1 to 9 and Comparative Examples 1 to 3. The substrate films of Examples 1 to 9 had a smaller difference between the maximum and minimum surface roughness values ​​than the substrate films of Comparative Examples 1 to 3, and therefore had a smaller difference between the maximum and minimum surface resistance values. Furthermore, in each of the substrate films of Examples 1 to 9, unlike the substrate films of Comparative Examples 1 to 3, the maximum surface resistance value was 10 １０ It was less than Ω / □.

[0070] 10 Base film, 20 Base layer, 21 Core layer, 22 Adhesive layer, 23 Surface layer, 30 Antistatic layer, 50 Manufacturing apparatus, 500 T-die, 510, 520 Cast roll, 530 Winding roll, F1 surface.

Claims

1. A substrate film for a tape used in the semiconductor manufacturing process, comprising: a base layer; and an antistatic layer laminated on the base layer, wherein the difference between the maximum value of the arithmetic mean roughness (Ra) and the minimum value of the arithmetic mean roughness (Ra) on the surface facing the antistatic layer is 1.1 μm or less.

2. The substrate film according to claim 1, wherein the difference between the maximum value of the arithmetic mean roughness (Ra) and the minimum value of the arithmetic mean roughness (Ra) on the surface on the antistatic layer side is less than 0.30 μm.

3. The substrate film according to claim 1, wherein the maximum value of the arithmetic mean roughness (Ra) on the surface on the antistatic layer side is divided by the thickness of the antistatic layer, and the result is less than 1.

0.

4. The substrate film according to claim 3, wherein the maximum value of the arithmetic mean roughness (Ra) on the surface on the antistatic layer side is divided by the thickness of the antistatic layer, and the result is less than 0.

16.

5. Surface resistance is 10 ９ Ω / □ or more, 10 １０ The substrate film according to any one of claims 1 to 4, having a resistance of less than Ω / □.

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