film

Abstract

The present invention addresses the problem of providing a film excellent in expandability (elongation percentage, uniform stretchability). The film satisfies (a) and (b). (a) The ratio E'(0) / E'(50) of the storage elastic modulus E'(0) at 0°C to the storage elastic modulus E'(50) at 50°C at an amplitude strain of 0.05% and 10 Hz is 5.0 or more. (b) The coefficient of static friction between surfaces of the film on at least one side is 0.5 or less.

Description

[Technical Field]

[0001] The present invention relates to a film that is excellent in expandability (elongation rate, uniform stretchability) and processability. [Background technology]

[0002] In the semiconductor chip manufacturing process, a semiconductor wafer such as a silicon wafer, sapphire wafer, or SiC wafer is diced (cut) into chips, and then expanded (stretched) to spread the chips apart to a fixed distance so that the chips can be picked up. A dicing film is used to secure the semiconductor wafer in place during the dicing and expanding processes.

[0003] The dicing film consists of an adhesive layer for fixing the semiconductor wafer and a base film that supports it. In the expanding process, the dicing film must be expanded radially to uniformly increase the spacing between the diced semiconductor chips. Therefore, the base film must have excellent expandability, i.e., the wafer loading area must be sufficiently stretched (high elongation) and stretched uniformly in all directions (uniform stretchability) during expansion.

[0004] Until now, polyvinyl chloride resin (PVC), which has high elongation and excellent uniform stretchability, has been the mainstream material used as the base film for this application. However, PVC has environmental issues, such as the inclusion of regulated substances such as dioctyl phthalate as a plasticizer, and its flame retardancy resulting in large CO2 emissions during disposal. As a result, dicing films using olefin-based resins as the base film have been proposed as an alternative material (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-9018 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-109808 Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Document 1 proposes a substrate film for dicing films that has improved elongation by adding components such as a copolymer of a vinyl aromatic compound and a conjugated diene or a hydrogenated derivative resin thereof to a polyolefin resin. However, because the material is flexible, there is a concern that the film will adhere to the stage of the device during expansion, resulting in insufficient slippage and insufficient elongation, which could cause problems with semiconductor chip pickup. Patent Document 2 also proposes a dicing tape with a slip layer, but there are concerns that processing the slip layer is expensive and that the substrate film is flexible, resulting in insufficient slippage and insufficient elongation, which could cause problems with semiconductor chip pickup.

[0007] An object of the present invention is to solve these problems and to provide a film that is excellent in expandability (elongation rate, uniform stretchability). [Means for solving the problem]

[0008] Preferred embodiments of the film of the present invention are as follows. (1) Films that satisfy the following (a) and (b): (a) The ratio E'(0) / E'(50) of the storage modulus E'(0) at 0°C to the storage modulus E'(50) at 50°C at an amplitude strain of 0.05% and 10 Hz is 5.0 or more. (b) The coefficient of static friction between at least one of the surfaces is 0.5 or less. (2) The film according to (1), wherein the storage modulus E'(0) is 800 MPa or more. (3) The film according to (1) or (2), wherein the indentation hardness of at least one surface is 33 MPa or more and 150 MPa or less in a loading / unloading test using nanoindentation. (4) The film according to any one of (1) to (3), wherein the height Spk of the protruding peaks on at least one surface is 0.2 μm or more and 2.0 μm or less, and the kurtosis Sku is 3.0 or more. (5) The film according to any one of (1) to (4), wherein the layer contains 40% by mass or more of a polyolefin resin when the total mass of at least one layer constituting the film is taken as 100% by mass. (6) The film according to any one of (1) to (5), which contains 10 to 60% by mass of a polypropylene-based resin. (7) The film according to any one of (1) to (6), which contains 5 to 60% by mass of a styrene-based elastomer and / or a 4-methyl-1-pentene-α-olefin copolymer. (8) The film according to any one of (1) to (5), which contains 10 to 60 mass% of a polypropylene-based resin relative to 100 mass% of the resin constituting the entire film, and further contains 5 to 60 mass% of a styrene-based elastomer and / or 5 to 60 mass% of a 4-methyl-1-pentene-α-olefin copolymer. (9) The film according to any one of (1) to (8), which has a tan δ peak at 5 to 50° C., and the peak value is 0.15 or more. (10) The film according to any one of (1) to (9), which has a melting point of 40 to 80°C. (11) The film according to any one of (1) to (10), which is used for wafer dicing.

[0009] In the expanding process, which is one of the manufacturing processes for semiconductor chips, a dicing film loaded with a wafer is typically placed on a circular stage, which is then pushed up to expand (stretch) the film. During this process, if there is significant friction between the outer edge of the circular stage and the film, the film may not be able to stretch sufficiently. Furthermore, the film on the top surface of the circular stage differs from the film positioned on the side after being pushed up. In this invention, we focused on the time-temperature conversion law of the film's slipperiness and viscoelasticity, and discovered that a film that satisfies the above (a) and (b) exhibits excellent expandability and processability. [Effects of the Invention]

[0010] According to the present invention, a film having excellent expandability (elongation rate, uniform stretchability) can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the film of the present invention will be described.

[0012] The film of the present invention is a film that satisfies the following (a) and (b). (a) The ratio E'(0) / E'(50) of the storage modulus E'(0) at 0°C to the storage modulus E'(50) at 50°C at an amplitude strain of 0.05% and 10 Hz is 5.0 or more. (b) The static friction coefficient of at least one of the outermost layers is 0.5 or less.

[0013] The film of the present invention preferably has at least a layer containing a resin, and may consist of one layer (i.e., a single layer) or two or more layers. When the film consists of multiple layers, these multiple layers may be the same or different from one another. That is, all layers may be the same, all layers may be different, or only some layers may be the same. When the multiple layers are different from one another, the combination of these multiple layers is not particularly limited as long as it does not impair the effects of the present invention. Here, "multiple layers are different from one another" means that at least one of the material and thickness of each layer is different from one another.

[0014] [E'(0) / E'(50)] The film of the present invention has a ratio E'(0) / E'(50) of the storage modulus E'(0) at 0°C to the storage modulus E'(50) at 50°C at an amplitude strain of 0.05% and 10 Hz, E'(0) / E'(50), of 5.0 or more. Here, the storage modulus E' refers to a value measured by DMA (dynamic mechanical analysis), and the measurement method is as described in the Examples. By controlling the E'(0) / E'(50) of the film of the present invention to 5.0 or more, the film of the present invention can be favorably stretched on the upper surface of the stage of a processing device when used in an expanding process, one of the manufacturing processes for semiconductor chips. From the above perspectives, E'(0) / E'(50) is preferably 7.0 or more, and more preferably 10.0 or more. Furthermore, from the viewpoint of maintaining excellent elongation during the dicing process while ensuring a balance of cuttability when cutting the film in each process, E'(0) / E'(50) is preferably 30.0 or less.

[0015] [Has a tan δ peak between 5 and 50°C, and the peak value is 0.15 or more] A preferred embodiment of the film of the present invention in which E'(0) / E'(50) is controlled to 5.0 or greater is one in which the film has a tan δ peak in the range of 5 to 50°C. A more preferred embodiment is one in which the film of the present invention has a tan δ peak in the range of 5 to 50°C, and the peak value is 0.15 or greater. Here, the tan δ peak refers to the maximum value of the loss tangent (tan δ) measured by DMA (dynamic viscoelasticity measurement), and the loss tangent refers to the ratio (E" / E') of the storage modulus E' to the loss modulus E". The tan δ peak in the present invention is a value measured by DMA (dynamic viscoelasticity measurement) described in the Examples. When the film of the present invention has two or more tan δ peaks, it is preferable that at least one tan δ peak be in the range of 5 to 50°C, and it is more preferable that at least one tan δ peak be in the range of 10 to 50°C.

[0016] By controlling the tan δ peak of the film within the range of 5 to 50°C, the decrease in storage modulus with increasing temperature within the same temperature range increases, and E'(0) / E'(50) can be favorably controlled. Furthermore, by controlling the peak value of the tan δ peak of the film of the present invention within the range of 5 to 50°C to 0.15 or more, the degree of decrease in storage modulus increases, making it possible to more favorably control E'(0) / E'(50), and improving the cuttability of the film when cutting it in each step while maintaining the elongation during the dicing step.

[0017] A preferred method for controlling the tan δ peak of the film of the present invention within the range of 5 to 50°C is to use a resin having a tan δ peak at 5 to 50°C in at least one of the thickest layers contained in the film of the present invention (or the entire film if it is a single layer).Preferred examples of such resins include low-crystalline polypropylene, amorphous polypropylene, propylene-α-olefin copolymer, olefin-based elastomers such as 4-methyl-1-pentene-α-olefin, styrene-based elastomers, and mixed resins of styrene-based elastomers and softeners for adjusting the tan δ peak.

[0018] The α-olefin is preferably a linear or branched α-olefin having 2 to 20 carbon atoms, more preferably an α-olefin having 2 to 10 carbon atoms. The styrene-based elastomer preferably includes copolymers of styrene and dienes, such as styrene-butadiene copolymer (SBR), styrene-isoprene-styrene copolymer (SIS), and styrene-butadiene-styrene copolymer (SBS), as well as their hydrogenated products (e.g., styrene-ethylene-butadiene-styrene copolymer (SEBS)). Also, styrene-isobutylene copolymers (e.g., styrene-isobutylene-styrene triblock copolymer (SIBS), styrene-isobutylene diblock copolymer (SIB), and mixtures thereof) are preferably used. When the styrene-based elastomer has a tanδ peak in the range of 5 to 50°C, the styrene-based elastomer alone may be used as a resin for controlling E'(0) / E'(50). However, when the tanδ peak of the styrene-based elastomer is less than 5°C, it is preferable to use the elastomer in combination with a softener to adjust the tanδ peak. As the softener, one or more types selected from the group consisting of petroleum resins such as aliphatic copolymers, aromatic copolymers, aliphatic-aromatic copolymers, and alicyclic copolymers, terpene resins, terpene phenol resins, rosin resins, alkylphenol resins, xylene resins, and hydrogenated products thereof can be preferably used.

[0019] Furthermore, from the viewpoint of controlling the tan δ peak value of the film of the present invention at 5 to 50°C to 0.15 or more, more preferred examples of resins having a tan δ peak at 5 to 50°C that are used in at least one of the thickest layers contained in the film of the present invention (or the entire film if it is a single layer) include amorphous polypropylene, 4-methyl-1-pentene-α-olefin copolymer, SEB, SEBS, SIB, and SIBS. Other preferred examples include mixed resins of SEB and / or SEBS with the softeners, or mixed resins of SIB and / or SIBS with the softeners.

[0020] [E'(0) is 800 MPa or more] The film of the present invention preferably has a storage modulus E'(0) of 800 MPa or more at 0°C under an amplitude strain of 0.05% and 10 Hz. By setting the storage modulus E'(0) to 800 MPa or more, it becomes possible to ensure a high elongation percentage of the film of the present invention while favorably controlling the cuttability when cutting the film to a predetermined size. From the same viewpoint, it is more preferable that the storage modulus E'(0) at 0°C is 1,000 MPa or more.

[0021] In order to control the storage modulus E'(0) of the film of the present invention to 800 MPa or more, it is preferable that the film of the present invention contains a resin having a high storage modulus at 0°C, and more preferably, one or more polypropylene-based resins selected from the group consisting of homopolypropylene, random copolymer of propylene and ethylene and / or butene-1, block polypropylene, propylene-α-olefin copolymer, propylene-ethylene-α-olefin copolymer, etc. Furthermore, it is preferable that E'(0) is 4000 MPa or less.

[0022] [Contains 10 to 60% by mass of polypropylene resin] The content of the polypropylene resin is preferably 10% by mass or more from the viewpoint of improving cuttability, and 60% by mass or less from the viewpoint of achieving both good elongation, when the entire film of the present invention is taken as 100% by mass, and more preferably 25 to 50% by mass.

[0023] [Containing 5 to 60 mass% of styrene elastomer and / or 4-methyl-1-pentene / α-olefin copolymer] Furthermore, from the viewpoint of achieving both elongation and cuttability, the film of the present invention preferably contains 5 to 60 mass% of the above-mentioned styrene elastomer and / or 4-methyl-1-pentene-α-olefin copolymer, when the entire film is taken as 100 mass%. From the viewpoint of the balance between elongation and cuttability, the content of the styrene elastomer and / or 4-methyl-1-pentene-α-olefin copolymer is more preferably 10 mass% or more, even more preferably 20 mass% or more, and even more preferably 40 mass% or more. From the same viewpoint, the content of the styrene elastomer and / or 4-methyl-1-pentene-α-olefin copolymer is preferably 50 mass% or less.

[0024] [Melting point between 40 and 80°C] Another preferred embodiment in which E'(0) / E'(50) is controlled to 5.0 or more is one in which the film of the present invention has a melting point of 40 to 80° C. The melting point in the present invention refers to a value measured by DSC (differential scanning calorimetry) described in the examples.

[0025] By setting the melting point of the film of the present invention within the above range, the storage modulus E'(50) at 50°C can be reduced and E'(0) / E'(50) can be suitably controlled while maintaining the cuttability and film stability at room temperature. Resins having a melting point of 40 to 80°C are preferably polyethylene-based resins such as low-crystalline ethylene-α-olefin copolymers, polypropylene-based resins such as propylene-α-olefin copolymers and propylene-ethylene-α-olefin copolymers, polybutene-based resins such as polybutene-1-ethylene copolymers and polybutene-1-propylene copolymers, and one or more selected from ethylene-ethyl (meth)acrylate copolymers, ethylene-methyl (meth)acrylate copolymers, ethylene-n-butyl (meth)acrylate copolymers, and ethylene-vinyl acetate copolymers. The α-olefin is not particularly limited as long as it is copolymerizable with propylene or ethylene, and examples thereof include 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-pentene, and 1-heptene.

[0026] [Static friction coefficient is 0.5 or less] The film of the present invention has a static friction coefficient of 0.5 or less between at least one surface thereof. The static friction coefficient in the present invention refers to the static friction coefficient evaluated by the method described in the examples.

[0027] As mentioned above, in the expanding process, which is one of the manufacturing processes for semiconductor chips, a dicing film loaded with wafers is generally placed on a circular stage of a processing device, and the circular stage is then pushed up to expand (stretch) the film. In this process, if friction between the surface of the circular stage or the outer edge of the film and the circular stage is high, film stretching may be hindered, preventing sufficient expansion of the chip spacing. However, by ensuring that the static friction coefficient between at least one surface is 0.5 or less, process stability during the production of the film of the present invention is improved, and friction between the film and the processing device during expansion of the dicing film using the film of the present invention is reduced, enabling high expandability (elongation rate, uniform stretchability). From the same perspective, the static friction coefficient is more preferably 0.4 or less. Furthermore, the static friction coefficient is preferably 0.1 or more.

[0028] Specific methods for making the static friction coefficient between at least one surface of the film of the present invention 0.5 or less will be described later. When the film of the present invention consists of two or more layers, a method of providing a resin layer B described later on the outermost surface can be preferably used. When the film of the present invention consists of a single layer, a method of embossing or coating with a lubricant can be preferably used.

[0029] As described above, the film of the present invention preferably has at least one layer containing a resin, and may be composed of one layer (i.e., a monolayer) or two or more layers. When the film of the present invention is a multilayer film composed of two or more layers, it is not particularly limited, but it preferably has, for example, resin layer A and resin layer B described below. It may have two layers, resin layer A and resin layer B, or may contain other layers as needed as long as the effects of the present invention are not impaired. More preferred configurations include a three-layer configuration having resin layer B, resin layer A, and resin layer C described below in this order, a three-layer configuration having resin layer B, resin layer A, and resin layer D described below in this order, and a four-layer configuration having resin layer B, resin layer A, resin layer C, and resin layer D in this order.

[0030] [Surface indentation hardness: 33 MPa to 150 MPa] The film of the present invention preferably has an indentation hardness of at least one surface of 33 MPa to 150 MPa in a load-unload test using nanoindentation. The indentation hardness in the present invention refers to the indentation hardness evaluated by the method described in the examples.

[0031] By ensuring that the indentation hardness of at least one surface is 33 MPa or more, excessive adhesion between the film and the upper surface of the circular stage of the processing device or the edge surfaces near the outer corners can be prevented when expanding a dicing film using the film of the present invention, resulting in better slippage. This improves the stretchability of the film on the upper surface of the processing device stage, making it possible to more sufficiently widen the chip spacing. Furthermore, the film's cuttability during the manufacturing process, processing process, and use can also be improved. Furthermore, the indentation hardness of the film of the present invention is preferably 150 MPa or less in order to ensure slippage while maintaining appropriate flexibility and making the film easy to stretch. From the same perspective, the indentation hardness is more preferably 70 MPa or more and 140 MPa or less.

[0032] In order to set the indentation hardness of at least one surface of the film of the present invention to 33 MPa or more and 150 MPa or less, a method of providing the outermost surface with a resin layer B described below can be preferably used. Specific methods will be described later, but the indentation hardness can be adjusted, for example, by using one or more resins selected from homopolypropylene, random copolymers of propylene and ethylene and / or butene-1, and block polypropylene for resin layer B.

[0033] From the same viewpoint as above, the indentation hardness of the surface where the coefficient of static friction between the two surfaces is 0.5 or less is preferably 33 MPa or more and 150 MPa or less, and more preferably 70 MPa or more and 140 MPa or less.

[0034] [Protruding peak height Spk is 0.2 μm or more and 2.0 μm or less] As mentioned above, friction occurs between the film and the surface and peripheral edge of the circular stage during the semiconductor chip expansion process. In particular, the film is likely to be pressed tightly against the stage at the peripheral edge (near the corners) due to the stage's upward thrust. If the height of the convex structures on the film surface that come into contact with the circular stage surface is too large, localized friction increases and slippage may be impaired. Furthermore, if the convex structures on the film surface are too small, the contact area between the stage and film increases, potentially impairing slippage.

[0035] By controlling the height Spk of the protruding peak on at least one film surface to 0.2 μm or more and 2.0 μm or less, the contact area between the stage and the film surface is prevented from increasing, improving the slipperiness and enabling the film on the stage surface to be stretched more fully.

[0036] Furthermore, by setting Spk to 2.0 μm or less, local friction between the film surface and the vicinity of the stage corner can be suppressed, thereby preventing the film on the side of the stage from being stretched alone, and enabling the film to be stretched more sufficiently up to the center of the upper surface of the stage. From the same perspective, Spk is more preferably 0.5 to 1.5 μm.

[0037] Spk is measured in accordance with ISO 25178-2 (2012) by the method described in the Examples. A method for controlling the height Spk of the protruding peaks on the film surface of the present invention to 0.2 μm or more and 2.0 μm or less includes providing a resin layer B (described later) on the outermost surface, and this control can be achieved by adjusting the material constituting layer B of the film of the present invention.

[0038] Specific examples of the resin layer B include a method of using block polypropylene, a method of using two or more incompatible resins, and a method of incorporating inorganic or organic particles into the resin layer B, which will be described later.

[0039] From the same viewpoint as above, the height Spk of the protruding peaks on the surface where the coefficient of static friction between the two surfaces is 0.5 or less is preferably 0.2 μm or more and 2.0 μm or less, and more preferably 0.5 to 1.5 μm.

[0040] [Kurtosis Sku is 3.0 or more] The film of the present invention preferably has a surface kurtosis Sku of 3.0 or more. Sku is one of the three-dimensional surface texture parameters defined in ISO 25178-2 (2012) and is an index indicating the degree of peaking of the height distribution from the mean plane. When Sku is 3, the surface shape is symmetrical with respect to the mean plane (normal distribution), when Sku exceeds 3, the height distribution has a peaked shape, and when Sku is less than 3, the height distribution tends to have a flat shape.

[0041] As mentioned above, during the semiconductor chip expansion process, friction occurs between the film and the upper surface and peripheral edge of the circular stage. The film is particularly prone to being pressed strongly against the stage at the peripheral edge (near the corners) due to the stage's upward thrust. If Sku is less than 3.0, the convex structure of the film surface is gentle, increasing the contact area between the stage and the film surface, potentially impairing slipperiness. By setting Sku to 3.0 or greater, the contact area between the stage and the film surface is reduced, improving slipperiness and enabling the film on the stage surface to be stretched more fully. Furthermore, to prevent excessive deformation of the film surface when a load is applied, which would otherwise reduce slipperiness during the expansion process, Sku is preferably 40 or less, more preferably 10 or less.

[0042] Sku is in accordance with the above ISO and is measured by the method described in the Examples. Specific methods for controlling the kurtosis Sku of the film surface of the present invention to 3.0 or more will be described later, including a method of providing a resin layer B described later on the outermost surface, and the control can be achieved by adjusting the material constituting layer B of the film of the present invention.

[0043] From the same viewpoint as above, it is preferable that the Sku of the surface where the coefficient of static friction between the two surfaces is 0.5 or less is 3.0 or more, and the Sku is preferably 40 or less, and more preferably 10 or less.

[0044] [Contains 40% or more by mass of polyolefin resin] From an environmental perspective, the film of the present invention is preferably a film in which the layer contains 40% by mass or more of a polyolefin resin when the total mass of at least one layer constituting the film is taken as 100% by mass.

[0045] The polyolefin resin in the present invention is preferably one or more selected from the group consisting of polyethylene resins such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and low-crystalline or amorphous ethylene-α-olefin copolymers; polypropylene resins such as homopolypropylene, random copolymers of propylene with ethylene and / or butene-1, block polypropylene, propylene-α-olefin copolymers, and propylene-ethylene-α-olefin copolymers; polybutene resins such as polybutene-1, polybutene-1-ethylene copolymers, and polybutene-1-propylene copolymers; 4-methyl-1-pentene-α-olefin copolymers; ethylene-ethyl (meth)acrylate copolymers; ethylene-methyl (meth)acrylate copolymers; ethylene-n-butyl (meth)acrylate copolymers; and ethylene-vinyl acetate copolymers. Examples of the α-olefin include propylene, ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-pentene, and 1-heptene.

[0046] Thickness The thickness of the film of the present invention can be adjusted appropriately depending on the required properties, but is preferably 10 to 200 μm, more preferably 20 to 150 μm, and particularly preferably 40 to 100 μm. If the film is thinner than 10 μm, the strength is insufficient, and it may be difficult to transport in the manufacturing process or may be torn during processing or use. If the film is thicker than 200 μm, the cutting ability may be reduced.

[0047] [Resin layer A] The resin layer A in the present invention will be described. The resin layer A is a layer containing at least a resin and is different from other layers. Furthermore, this resin layer A refers to a layer having a finite thickness, and is preferably a layer having excellent expandability (elongation rate, uniform stretchability) in the film of the present invention.

[0048] Furthermore, the resin layer A is preferably the thickest layer (or the entire film if it is a single layer) among the layers contained in the film of the present invention. The thickness of the resin layer A can be adjusted appropriately according to the required properties of the film of the present invention, but it is preferably a layer structure of 40% or more and 95% or less when the thickness of all layers of the film of the present invention is taken as 100%. If the layer structure of the resin layer A is less than 40%, the expandability (elongation rate, uniform stretchability) of the film of the present invention may decrease. The expandability (elongation rate, uniform stretchability) becomes more stable as the layer structure ratio of the resin layer A increases, so it is more preferably 50% or more, and even more preferably 60% or more. If the layer structure of the resin layer A exceeds 95%, the effect of the easy slip property of the resin layer B described below may be impaired.

[0049] The resin used in the resin layer A of the film of the present invention is not particularly limited, and thermoplastic resins such as polyolefin and polyester can be used, but it is more preferable to use polyolefin as the main component from the viewpoints of environmental considerations, productivity, processability, etc. Here, "using polyolefin as the main component" means that when the entire resin layer A is taken as 100% by mass, the proportion of polyolefin is 50% by mass or more, more preferably 70% by mass or more.

[0050] The polyolefin may preferably be at least one selected from the group consisting of polyethylene-based resins such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and low-crystalline or amorphous ethylene-α-olefin copolymers; polypropylene-based resins such as homopolypropylene, random copolymers of propylene and ethylene and / or butene-1, block polypropylene, propylene-α-olefin copolymers, and propylene-ethylene-α-olefin copolymers; polybutene-based resins such as polybutene-1, polybutene-1-ethylene copolymers, and polybutene-1-propylene copolymers; 4-methyl-1-pentene-α-olefin copolymers; ethylene-ethyl (meth)acrylate copolymers; ethylene-methyl (meth)acrylate copolymers; ethylene-n-butyl (meth)acrylate copolymers; and ethylene-vinyl acetate copolymers. Examples of the α-olefin include propylene, ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-pentene, and 1-heptene. Among these polyolefins, polyethylene resins, polypropylene resins, polybutene resins, and 4-methyl-1-pentene-α-olefin copolymers are more preferably used from the viewpoint of improving processability and expandability (elongation and uniform stretchability).

[0051] [Resin layer B] Next, the resin layer B in the present invention will be described. The resin layer B is a layer that contains at least a resin, and is a layer that is different from the resin layer A and other layers. Furthermore, this resin layer B refers to a layer having a finite thickness.

[0052] The film of the present invention is characterized in that the static friction coefficient between at least one surface thereof is 0.5 or less. As described above, one specific method for controlling the friction coefficient to 0.5 or less is to provide a resin layer B having excellent slip properties on at least one surface.

[0053] For example, when a film including resin layer A and resin layer B is produced by a co-extrusion method, it is possible to control the surface shape (Spk, Sku) and surface hardness of resin layer B, which will be described later, by adjusting the material constituting resin layer B and the production conditions. This eliminates the need for processes such as embossing and lubricant coating, thereby improving productivity.

[0054] Although thermoplastic resins such as polyolefin and polyester can be used for the resin layer B, it is more preferable that the resin layer B be mainly composed of polyolefin from the viewpoints of productivity, processability, etc. Here, "mainly composed of polyolefin" means that the proportion of polyolefin is 50% by mass or more, and more preferably 70% by mass or more, when the entire resin layer B is taken as 100% by mass.

[0055] Resins similar to the polyolefins suitable for the resin layer A described above can be preferably used for the resin layer B. Among these, from the viewpoint of improving productivity, processability, and the lubricity of the film of the present invention, there are mentioned a method using block polypropylene, a method using two or more incompatible resins selected from the group consisting of high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), homopolypropylene, a random copolymer of propylene and ethylene and / or butene-1, and block polypropylene, a method using inorganic particles or organic particles to roughen at least one surface, and a method using an additive such as a lubricant. These methods may be used alone or in combination of two or more.

[0056] The inorganic particles may be one or more types of inorganic particles selected from the group consisting of inorganic oxide particles (silica particles, alumina particles, titanium oxide particles, etc.), inorganic carbonate particles (calcium carbonate particles, barium carbonate particles, etc.), and inorganic silicate particles (aluminum silicate particles, talc particles, kaolin particles, etc.). The organic particles may be one or more types of organic particles selected from the group consisting of acrylic resin particles, polyolefin resin particles (polyethylene resin particles, polypropylene resin particles), and polystyrene resin particles.

[0057] The lubricant is preferably at least one selected from the group consisting of fatty acid amides, metal soaps, fluorine-based polymers, silicone-based lubricants, fatty acids, and vegetable oils.

[0058] Furthermore, the film of the present invention preferably has a peak height Spk of 0.2 μm or more and 2.0 μm or less, and a kurtosis Sku of 3.0 or more.

[0059] During the semiconductor chip expanding process, friction occurs between the film and the upper surface of the circular stage or the outer edge face. However, by controlling the convex structure of the film surface within the above-mentioned range, the contact area of ​​the film surface that comes into contact with the upper surface of the circular stage is prevented from increasing, improving the slipperiness and enabling the film on the upper surface of the stage to be sufficiently stretched.

[0060] More preferred methods for controlling Spk and Sku within preferred ranges include using block polypropylene, using two or more incompatible resins in resin layer B, and incorporating inorganic or organic particles in resin layer B. Furthermore, from the viewpoint of suppressing process contamination due to particle shedding during processing, using two or more incompatible resins in resin layer B is even more preferred. The method of using two or more incompatible resins makes it possible to control the dispersion state (matrix / domain) by changing the combination of resins constituting resin layer B, extrusion conditions, and film-forming conditions, thereby enabling flexible design of the convex structure on the film surface. For example, when using two or more incompatible resins in resin layer B and controlling Spk and Sku by the combination of resins, these can be controlled by the difference in melt viscosity at the extrusion temperature, as described below.

[0061] Furthermore, it is more preferable that the indentation hardness of at least one surface of the film of the present invention is 40 MPa or more and 150 MPa or less in a load-unloading test using nanoindentation. As a method for controlling the indentation hardness within the above-mentioned range and increasing the ease of slippage, it is particularly preferable to use, in the resin layer B of the present invention, one or more polypropylene-based resins b selected from homopolypropylene, random copolymers of propylene and ethylene and / or butene-1, and block polypropylene, in combination with high-density polyethylene (HDPE) that is incompatible with the polypropylene-based resins b.

[0062] When polypropylene resin b and high-density polyethylene are used in combination in resin layer B, the proportion of polypropylene resin b used in resin layer B, when the entire resin layer B is taken as 100% by mass, is preferably 10% by mass or more, and more preferably 20% by mass or more, from the viewpoint of favorably controlling the indentation hardness and the ratio E'(0) / E'(50) of the storage modulus E'(50). Similarly, from the viewpoint of improving lubricity, the proportion of high-density polyethylene used in resin layer B is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more.

[0063] When polypropylene resin b and high-density polyethylene are used in combination in resin layer B, in order to improve the Spk to 0.2 μm or more, the temperature is set at 230°C, the shear rate is set at 122 s -1 The difference in melt viscosity between the polypropylene-based resin b and the high-density polyethylene at 230°C and a shear rate of 122 s is preferably 300 Pa·s or more. -1 The difference in melt viscosity between the polypropylene resin b and the high-density polyethylene in the resin layer B is preferably 1000 Pa s or less. The melt viscosity is evaluated by the method described in the examples. When two or more types of polypropylene resin b are used in the resin layer B or when two or more types of high-density polyethylene are used, the melt viscosity can be evaluated using a resin obtained by melt-kneading two or more types of polypropylene resin b together or two or more types of high-density polyethylene together in advance.

[0064] The thickness of resin layer B can be adjusted appropriately according to the required properties of the film of the present invention, but is preferably 5% or more and 20% or less when the total thickness of the entire film layer of the film of the present invention is taken as 100%. If the thickness of resin layer B is less than 5%, the film of the present invention may become thin-film laminated during film formation, making production more difficult, or the lubricity that is the effect of resin layer B may not be fully exhibited. Furthermore, if the layer structure of resin layer B exceeds 20%, the expandability (elongation rate, uniform stretchability) of the film of the present invention may be insufficient.

[0065] [Resin layer C] The resin layer C in the present invention is a layer containing at least a resin. The resin layer C refers to a layer having a finite thickness, and is preferably a layer having excellent dicing properties in the film of the present invention.

[0066] Here, dicing property means that cutting waste is less likely to be generated on the base film during the process of dicing (cutting) semiconductor wafers such as silicon wafers, sapphire wafers, and SiC wafers into chips in the semiconductor chip manufacturing process.

[0067] An olefin-based elastomer is preferably used as the resin used in the resin layer C of the film of the present invention. By using an olefin-based elastomer, cutting debris during dicing is suppressed and a sufficient elongation percentage is obtained.

[0068] Although known olefin elastomers can be used as the olefin elastomer, it is preferable to use one or more α-olefin elastomers selected from the group consisting of ethylene elastomers, propylene elastomers, 1-butene elastomers, and 4-methylpentene-1 elastomers (propylene-ethylene copolymers, propylene-1-butene copolymers, propylene-ethylene-1-butene copolymers, 1-butene homopolymers, 1-butene-ethylene copolymers, 1-butene-propylene copolymers, 4-methylpentene-1 homopolymers, 4-methylpentene-1-propylene copolymers, 4-methylpentene-1-1-butene copolymers, 4-methylpentene-1-propylene-1-butene copolymers, and combinations thereof). From the viewpoint of reducing chips during dicing, propylene elastomers and 1-butene elastomers are particularly preferred, with propylene elastomers being particularly preferred.

[0069] Furthermore, the resin layer C may contain one or more resins selected from the group consisting of these α-olefin elastomers in combination with LLDPE, LDPE, HDPE, homopolypropylene, random copolymers of propylene and ethylene and / or butene-1, block polypropylene, propylene-α-olefin copolymers, and propylene-ethylene-α-olefin copolymer polypropylenes.

[0070] The thickness of resin layer C can be adjusted appropriately according to the required properties of the film of the present invention, but it is preferable that the thickness of resin layer C is 10% or more and 25% or less when the thickness of all layers of the film of the present invention is 100%. If the layer structure of resin layer C is less than 10%, thin film lamination occurs during film formation of the film of the present invention, making production more difficult, or the cuttability that is the effect of resin layer C may not be fully exhibited. Furthermore, if the layer structure of resin layer C exceeds 25%, the elongation of the film of the present invention may be insufficient.

[0071] [Resin layer D] In the film of the present invention, in addition to the above-mentioned resin layer A, resin layer B, and resin layer C, a resin layer D having adhesive properties can be disposed as the outermost layer.

[0072] The resin layer D may be made of any of a cross-linked material such as an acrylic or silicone material, or a non-cross-linked or pseudo-cross-linked (thermoplastic) material such as a natural rubber or synthetic rubber material. For example, when a film including the resin layer D is produced by a co-extrusion method, it is preferable that the main component be a thermoplastic resin from the viewpoint of recyclability. Here, "mainly made of a thermoplastic resin" means that the proportion of the thermoplastic resin in the composition is 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more.

[0073] Resins suitable for the resin layer D include styrene-based elastomers such as copolymers of styrene and dienes, such as styrene-butadiene copolymer (SBR), styrene-isoprene-styrene copolymer (SIS), and styrene-butadiene-styrene copolymer (SBS), and hydrogenated products thereof (e.g., styrene-ethylene-butadiene-styrene copolymer (SEBS)), and styrene-isobutylene copolymers (e.g., styrene-isobutylene block copolymers, such as styrene-isobutylene-styrene triblock copolymer (SIBS), styrene-isobutylene diblock copolymer (SIB), or mixtures thereof); polyethylene-based resins, such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and ethylene-α-olefin copolymers; polypropylene-based resins, such as propylene-α-olefin copolymer and propylene-ethylene-α-olefin copolymer; and polybutene-based resins, such as polybutene-1-ethylene copolymer and polybutene-1-propylene copolymer. In addition to the resin suitable for the resin layer D described above, it is more preferable that the adhesive layer further contains a tackifier such as a petroleum resin such as an aliphatic copolymer, an aromatic copolymer, an aliphatic-aromatic copolymer, or an alicyclic copolymer, a terpene resin, a terpene phenol resin, a rosin resin, an alkylphenol resin, a xylene resin, or a hydrogenated product thereof, in order to enhance the adhesiveness of the adhesive layer.

[0074] When the film of the present invention is made up of one layer (i.e., a single layer), the resin used in the film of the present invention is preferably the same as the polyolefin suitable for the resin layer A described above, in order to ensure the expandability (elongation rate, uniform stretchability) of the film. Furthermore, when the film of the present invention is made up of one layer (i.e., a single layer), from the viewpoint of controlling the static friction coefficient between at least one surface to 0.5 or less, it is preferable that at least one surface is textured or coated with a lubricant.

[0075] Each layer of the film of the present invention may contain, as necessary, particles other than those described above, lubricants, crystal nucleating agents, antioxidants, heat resistance agents, weather resistance agents, antistatic agents, etc. The amount of these components added is preferably 5% by mass or less, and more preferably 3% by mass or less, when the total mass of each layer is taken as 100% by mass.

[0076] Next, the method for producing the film of the present invention will be described.

[0077] The method for producing the film of the present invention is not particularly limited, and examples thereof include a three-layer laminate structure of resin layer B, resin layer A, and resin layer C, or a three-layer laminate structure of resin layer B, resin layer A, and resin layer D. Examples include a so-called coextrusion method in which the respective constituent resins are melt-extruded from separate extruders and laminated together in a die, and a method in which resin layer B, resin layer A, and resin layer C, or resin layer B, resin layer A, and resin layer D, are each melt-extruded separately and then laminated by a lamination method. From the viewpoint of productivity, production by the coextrusion method is preferred. As the coextrusion method, known methods such as an inflation method and a T-die method are used, but from the viewpoint of excellent thickness precision and surface profile control, hot-melt coextrusion using a T-die method is particularly preferred.

[0078] As a manufacturing method other than the above, after "resin layer B, resin layer A" or "resin layer B, resin layer A, resin layer C" are manufactured by hot melt co-extrusion, resin layer D can also be provided by coating.

[0079] The film of the present invention can be preferably used as an industrial film such as a protective film or a process film, and in particular can be preferably used as a substrate film for a dicing film or a dicing film used to fix a semiconductor wafer when dicing the semiconductor wafer into chips. [Example]

[0080] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Measurements and evaluations of various physical properties were carried out by the following methods, and unless otherwise specified, the measurements were carried out indoors at 23°C and 65% RH.

[0081] <Evaluation method> (1) Storage modulus E' and loss tangent tanδ of the film Measurement samples were cut into 10 mm wide rectangular specimens. Based on the tensile vibration-nonresonance method (referred to as the dynamic viscoelasticity method) of JIS K7244-4 (1999), the storage modulus and loss tangent of the film at a frequency of 10 Hz were determined using a Seiko Instruments Inc. DMS6100 dynamic viscoelasticity measuring device. The storage modulus at 0°C was read as E'(0) and the storage modulus at 50°C as E'(50), and the storage modulus at each temperature was determined. E'(0) / E'(50) was also calculated. For the loss tangent tanδ, the peak temperature and the peak value of the loss tangent tanδ at the peak temperature were read from the loss tangent chart. When no peak value of the loss tangent tanδ was observed within the range of 5 to 50°C, this was indicated as "-" in Tables 1 and 2. Measurement mode: Tensile Test piece width: 5mm Frequency: 10Hz Amplitude distortion: 0.05% Measurement temperature: -50℃ to 100℃ Heating rate: 3°C / min.

[0082] (2) Measurement of static friction coefficient After conditioning the film at 23°C and 65% RH, it was cut into a strip of 75 mm wide and 100 mm long, with the longitudinal direction of the film production line, to prepare a sample. The slip coefficient was measured in an atmosphere of 23°C and 65% RH using a slip coefficient measuring device (Model ST-200, manufactured by Techno Needs Corporation).

[0083] Specifically, a sample cut into a strip was placed on the measurement sample stage of the device so that the pulling direction was longitudinal, and the end of the sample was fixed to the load detection U-gauge of the device. The film was then left to stand, and a Teflon (registered trademark) sheet with a sample contact surface of 6.5 cm x 6.5 cm and a 200 g weight was placed on top of it to bring the samples into close contact with each other. After that, the static friction coefficient was measured 10 times when the upper film was pulled under the following conditions, and the static friction coefficient μs was calculated by averaging the six measurements, excluding the top two and bottom two points. Measurement distance: 15mm Measurement speed: 300mm / min.

[0084] (3) Melting point measurement In accordance with JIS K-7122 (1987), 3.0 mg of film was weighed and heated at a rate of 20°C / min from -30°C to 200°C using a differential scanning calorimeter (Rigaku Thermo plus EVO2 DSCvesta) to obtain a differential scanning calorimeter chart. The melting peak temperature was determined from the obtained differential scanning calorimeter chart according to the method described in JIS K-7121 (1987), and the presence or absence of a melting peak temperature (melting point) between 40 and 80°C and its temperature were confirmed. When a melting peak temperature (melting point) was not observed between 40 and 80°C, it was indicated as "-" in Tables 1 and 2.

[0085] (3-2) Resin crystallization temperature In accordance with JIS K-7121 (2012), the resins used in the examples and comparative examples were measured under the following conditions using a differential scanning calorimeter (Rigaku Thermo plus EVO2 DSCvesta), and the crystallization temperature was determined from the differential scanning calorimeter curve obtained in step (iii). Sample amount: 3 mg Heating rate, cooling rate: 20℃ / min Temperature Program: Step (i) increasing the temperature from 30°C to 250°C; Step (ii) maintaining at 250°C for 5 minutes; Step (iii) The temperature is lowered from 250°C to -30°C.

[0086] (4) Thickness When the film was a laminate film, a cross-sectional slice having a cross section in the width direction and thickness direction of the laminate film was prepared using a microtome method, and the cross section was platinum-coated to prepare an observation sample. Next, the cross section of the laminate film was observed at an arbitrary magnification using a field emission scanning electron microscope (S-4800) manufactured by Hitachi, Ltd., and the thicknesses of resin layer B, resin layer A, and resin layer C were measured.

[0087] (5) Evaluation of expandability (elongation rate, uniform stretchability) A sample was cut out to a size of 300 mm x 200 mm so that the film production line direction (MD) of the measurement sample was the long side. A 5 mm grid was printed horizontally and vertically on a 100 mm square from the center of the cut-out sample, based on the film production line direction (MD) of the measurement sample. The sample was set so that the surface of resin layer B was in contact with the surface on the stage of an expander (manufactured by Hugle) and so that the printed grid overlapped the stage, and expanded at a stage temperature of 25°C.

[0088] After expanding, the lattice size at the center of the sample was measured, and the elongation rates in the film production line direction (MD) and the perpendicular direction (TD) were calculated to evaluate the expandability. The elongation was calculated at 20 points in each of the MD and TD, and the average value of the MD and TD values ​​was used as the elongation. The uniform stretchability was evaluated using the ratio of the expanded elongation obtained in the MD and TD. Stage height: 40mm Stage temperature: 25℃.

[0089] <Growth rate evaluation criteria> The elongation rate was calculated for 20 points each in MD and TD. The average value of the elongation rates in MD and TD. D or above is within the practical range. S: 15% or more A: 12% or more B: 10% or more C: 7% or more D: 5% or more E: Less than 5%.

[0090] <Evaluation criteria for uniform stretchability> The ratio of the expanded elongation obtained in MD and TD (MD / TD). B or higher is within the practical range. A: 0.9 or more and less than 1.1 B: 0.8 or more and less than 0.9, or 1.1 or more and less than 1.2 C: Less than 0.8 or more than 1.2.

[0091] (6) Cutting performance evaluation a The sample film was cut with a cutter knife in an atmosphere of 23°C and 65% RH, and the state of the edge formed was visually observed, and the cuttability of the film was evaluated according to the following criteria. A commonly available commercially available circle cutter was used to cut a circle with a diameter of 150 mm. The blade was replaced with a new one after each measurement. A grade of B or higher is within the practical range. A: Smooth cutting was possible. B: A relatively good cut was possible. C: After cutting, notches and whiskers appeared on the cross section, and in some cases the sample stretched.

[0092] (6-2) Cutting performance evaluation b In an atmosphere of 23°C and 65% RH, the film was cut into a circle with a diameter of 150 mm from the A layer side using an OLFA rotary compass cutter. The condition of the cut circumference was visually inspected to check for cutting defects such as notches, whiskers, and film stretching, and the film's cuttability was evaluated according to the following criteria. The blade was replaced with a new one after each measurement. A: The cutting defect was less than one-eighth of the circumference. B: The cut defect was less than one-quarter of the circumference. C: The cut defect was less than one-third of the circumference. D: Defective cuts occurred in less than two-fifths of the circumference. E: Defective cutting occurred in more than two-fifths of the circumference.

[0093] (7) Loss tangent of elastomer (tanδ) Pellets made from the elastomer used in the examples were melt-molded to a thickness of 1 mm to prepare samples. Measurements were performed using a TA Instruments AR2000ex rheometer. The sample was cooled from 200°C to -20°C at a rate of 20°C / min, and then heated from -20°C to 80°C at a rate of 10°C / min, while being subjected to dynamic shear deformation at a frequency of 1 Hz and a strain of 0.01%, and tan δ was evaluated during the heating process.

[0094] (8) Indentation hardness Using an Elionix nanoindentation tester ENT-2100, an indentation test was carried out on the surface of resin layer B using a load-unload test under the following conditions: For each type of film, an arbitrary point was set as the base point, and measurements were taken at 1 mm intervals in the cross direction in MD and TD, three points on each side (13 points in total), from this base point (13 points in total). Of the indentation hardness values ​​obtained, the top two and bottom two points were excluded, and the average of six measurements was taken as the indentation hardness of the surface of resin layer B. Indenter: Elionix Berkovich indenter (triangular pyramid tip, made of diamond) Temperature: 23℃ Maximum load: 0.10mN Loading speed / unloading speed: 0.01mN / s Load at the start of the load-unload test: 0 mN Hold time at maximum load: 1 second Surface detection method: Tilt method Surface detection threshold factor: 1.5 Spring compensation: Real-time spring compensation.

[0095] (9) Spk, Sku The surface of resin layer B was measured using a Hitachi High-Tech Science Corporation scanning white light interference microscope (VS1540) under the following conditions and with the following equipment configuration in accordance with ISO 25178-2 (2012). The images were interpolated (fully interpolated) using the accompanying analysis software, and surface correction was performed using a polynomial fourth-order approximation. The image was then processed using a median filter (3 x 3 pixels) to determine the peak height Spk (μm) and kurtosis Sku. Five measurements were performed for each type of film, and the arithmetic mean of the five Spk (μm) values ​​was used to determine the film's Spk (μm). Similarly, the arithmetic mean of the five Sku values ​​was used to determine the film's Sku.

[0096] <Measurement conditions and equipment configuration> Objective lens: 10x Telescope tube: 1x Zoom lens: 1x Wavelength filter: 530nm white Measurement mode: Wave Measurement software: VS-Measure 10.0.4.0 Analysis software: VS-Viewer 10.0.3.0 Measurement range: 1009.7 μm x 1010.5 μm (The above range was measured by connecting 2 fields of view x 2 fields of view, a total of 4 fields of view) Number of pixels: 1842 x 1844.

[0097] (10) Melt viscosity Using a Toyo Seiki Capillograph (1D), the temperature was 230°C and the shear rate was 122 s -1 The melt viscosity of the resins used in the examples and comparative examples was measured.

[0098] The resins used in the examples and comparative examples are shown below.

[0099] <bpp> Commercially available block polypropylene, MFR 8.5 g / 10 min (measured at 230°C), melt viscosity 370 Pa·s (temperature 230°C, shear rate 122 s -1 (Measured at . The same applies below.)

[0100] <hpp> A commercially available homopolypropylene with a melt viscosity of 410 Pa·s, a crystallization temperature of 113°C, and a melting point of 165°C.

[0101] <rpp> A commercially available metallocene-based random polypropylene with a melt viscosity of 510 Pa·s, a crystallization temperature of 101°C, and a melting point of 136°C. <hdpe1> Melt viscosity 1090 Pa s, crystallization temperature 116°C, melting point 136°C, density 0.960 g / cm 3 of commercially available high density polyethylene <hdpe2> Melt viscosity 1290 Pa s, crystallization temperature 114°C, melting point 132°C, density 0.962 g / cm 3 of commercially available high density polyethylene <lldpe-1> Product name: "Evolue" (registered trademark) SP0540, manufactured by Prime Polymer Co., Ltd. Melt viscosity 780 Pa s, density 0.904 g / cm 3 , MFR 3.8g / 10min (measured at 190℃).

[0102] <lldpe-2> Product name: Evolue (registered trademark) SP2040, manufactured by Prime Polymer Co., Ltd. Melt viscosity: 830 Pa·s, density: 0.918 g / cm 3 , MFR 3.8g / 10min (measured at 190℃).

[0103] <tpe-1> PP elastomer Product name: Vistamax (registered trademark) 3980FL, manufactured by ExxonMobil Corporation Density 0.879g / cm 3 , MFR 8.0 g / min (measured at 230°C).

[0104] <tpe-2> PP elastomer Product name: "Tafmer" (registered trademark) PN2060, manufactured by Mitsui Chemicals, Inc. Density 0.868g / cm 3 , MFR 6.0g / 10min (measured at 230℃).

[0105] <tpe-3> Polyolefin elastomer (4-methyl-1-pentene-α-olefin copolymer) Product name: "Absortomer" (registered trademark) EP-1013, manufactured by Mitsui Chemicals, Inc. MFR 10g / 10min (measured at 230℃). Tan δ peak temperature 34°C, tan δ (34°C) 0.5.

[0106] <tpe-4> Polyolefin elastomer (4-methyl-1-pentene-α-olefin copolymer) Product name: "Absortomer" (registered trademark) EP-1001, manufactured by Mitsui Chemicals, Inc. MFR 10g / 10min (measured at 230℃) Tan δ peak temperature 32°C, tan δ (32°C) 2.4.

[0107] <tpe-5> styrene elastomer Product name "SOE" S1605, Asahi Kasei Density 1.0g / cm 3 , MFR 5g / 10min (measured at 230℃), Tan δ peak temperature 16°C, tan δ(16°C) 1.3.

[0108] <pb> Product name: "Tufmer" (registered trademark) BL4000, manufactured by Mitsui Chemicals MFR 1.8 g / 10 min (measured at 190°C).

[0109] <PE particle masterbatch (PE particle MB)> A polyethylene particle masterbatch with a mass ratio of 10:90 was prepared from high molecular weight polyethylene fine particles "Mipelon" (registered trademark) PM200, with an average particle diameter of 10 μm and manufactured by Mitsui Chemicals, and metallocene linear low density polyethylene ("Evolue" (registered trademark) SP2040, manufactured by Prime Polymer Co., Ltd., MFR 3.8 g / min (measured at 190°C, 21.17 N)). The following Examples 1-7, 13, and 27 should be read as Reference Examples 1-7, 13, and 27.

[0110] <Examples 1 and 2> The constituent resins of each layer described in Table 1 were charged into each extruder of a T-die composite film forming machine with a multi-manifold having a die width of 2,400 mm and two extruders with diameters of φ115 mm (for resin layer A) and φ65 mm (for resin layer B). The discharge amounts of each extruder were adjusted so that the thickness ratio of resin layer B was 15% and the thickness ratio of resin layer A was 85%. The resin was extruded from the composite T-die at an extrusion temperature of 200°C each to form a two-layer film with a film thickness of 80 μm.

[0111] <Examples 3 to 6> The constituent resins of each layer described in Table 1 were charged into each extruder of a T-die composite film forming machine with a multi-manifold having a die width of 2,400 mm and three extruders with diameters of φ115 mm (for resin layer A), φ90 mm (for resin layer C), and φ65 mm (for resin layer B). The discharge amounts of each extruder were adjusted so that the thickness ratio of resin layer C was 20%, the thickness ratio of resin layer B was 15%, and the thickness ratio of resin layer A was 65%. The resin was extruded from the composite T-die at an extrusion temperature of 200°C each to form a three-layer film with a film thickness of 80 μm and a structure of resin layer B / resin layer A / resin layer C.

[0112] <Examples 7 to 14, 16 to 31> A three-layer film having a resin layer B / resin layer A / resin layer C structure was formed in the same manner as in Examples 3 to 6, except that the constituent resins of each layer shown in Tables 2, 3 and 4 were used.

[0113] Example 15 A three-layer film having a resin layer B / resin layer A / resin layer C structure was formed in the same manner as in Examples 3 to 6, except that the constituent resins of each layer listed in Table 3 were used. Then, the surface of resin layer B (commercially available metallocene-based random polypropylene with a melt viscosity of 510 Pa·s, a crystallization temperature of 101°C, and a melting point of 136°C, 100% surface) was hot-pressed with an embossing roll to apply a graining finish.

[0114] <Comparative Example 1> The constituent resins of each layer listed in Table 5 were fed into each extruder of a multi-manifold T-die composite film-forming machine with a nozzle width of 2,400 mm, which had two extruders consisting of a φ115 mm (for resin layer A) and a φ90 mm (for resin layer C).The output of each extruder was adjusted so that the thickness ratio of resin layer C was 20% and the thickness ratio of resin layer A was 80%, and the films were extruded from the composite T-die at an extrusion temperature of 200°C to form a two-layer film with a film thickness of 80 μm.

[0115] <Comparative Examples 2 and 3> The constituent resins of each layer listed in Table 5 were fed into each extruder of a multi-manifold T-die composite film-forming machine with a nozzle width of 2,400 mm, which had three extruders consisting of φ115 mm (for resin layer A), φ90 mm (for resin layer C), and φ65 mm (for resin layer B).The output of each extruder was adjusted so that the thickness ratio of resin layer C was 20%, the thickness ratio of resin layer B was 15%, and the thickness ratio of resin layer A was 65%.The films were extruded from the composite T-die at an extrusion temperature of 200°C, and a three-layer film with a resin layer B / resin layer A / resin layer C composition and a film thickness of 80 μm was formed.

[0116] [Table 1]

[0117] [Table 2]

[0118]

Table 3

[0119]

Table 4

[0120]

Table 5

Claims

1. It consists of at least two layers and satisfies the following (a), (b), and (c): When the thickness of all layers of the film is taken as 100%, the thickness of the resin layer B having a surface satisfying (b) and (c) is 5% or more and 20% or less, A film containing 16% by mass or more and 60% by mass or less of a styrene-based elastomer and / or a 4-methyl-1-pentene / α-olefin copolymer when the entire film is taken as 100% by mass. (a) The ratio E'(0) / E'(50) of the storage modulus E'(0) at 0°C and the storage modulus E'(50) at 50°C at an amplitude strain of 0.05% and 10 Hz is 5.0 or more. (b) The coefficient of static friction between at least one of the surfaces is 0.5 or less. (c) In a loading / unloading test using nanoindentation, the indentation hardness of at least one surface is 33 MPa or more and 150 MPa or less.

2. 2. The film of claim 1, wherein the storage modulus E'(0) is 800 MPa or greater.

3. 3. The film according to claim 1, wherein at least one surface has a peak height Spk of 0.2 μm or more and 2.0 μm or less, and a kurtosis Sku of 3.0 or more.

4. 3. The film according to claim 1, wherein the layer contains 40% by mass or more of a polyolefin resin when the total mass of at least one layer constituting the film is taken as 100% by mass.

5. The film according to claim 1 or 2, comprising 10 to 60% by mass of a polypropylene-based resin.

6. 3. The film according to claim 1, wherein the film contains 10 to 60% by mass of a polypropylene-based resin, and further contains 5 to 60% by mass of a styrene-based elastomer and / or 5 to 60% by mass of a 4-methyl-1-pentene / α-olefin copolymer, relative to 100% by mass of the resin constituting the entire film.

7. 3. The film according to claim 1, which has a tan δ peak at 5 to 50° C., the peak value being 0.15 or more.

8. 3. The film according to claim 1, having a melting point of 40 to 80°C.

9. The film according to claim 1 or 2, which is used for wafer dicing.

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