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

film

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

[0002] In the manufacturing process of semiconductor chips, a semiconductor wafer such as a silicon wafer, a sapphire wafer, or a SiC wafer is diced (cut) into chips, and then expanded (stretched) to widen the gap between the chips and pick them up. A dicing film is used to fix 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 is required to have excellent expandability, i.e., to ensure that the wafer-loading area is sufficiently stretched (high elongation) and stretched uniformly in all directions (uniform stretchability) during expansion.

[0004] Until now, vinyl chloride resin (PVC), which has high elongation and excellent uniform stretchability, has been the mainstream material used for this purpose as a base film. However, PVC contains regulated substances such as dioctyl phthalate as a plasticizer, and is flame-retardant, emitting CO2 during disposal. ２ There are environmental load issues such as high emissions, and as an alternative material, dicing films using olefin resin as the base film have been proposed (Patent Documents 1 and 2).

[0005] JP 2002-9018 A JP 2007-109808 A

[0006] Patent Document 1 proposes a substrate film for dicing films that has improved elongation by adding a component 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 may 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 may 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).

[0008] Preferred embodiments of the film of the present invention are as follows. (1) 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 coefficient of static friction between at least one surface is 0.5 or less; (2) The film according to (1), in which the storage modulus E'(0) is 800 MPa or more; (3) The film according to (1) or (2), in which 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), in which the peak height Spk of 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-based 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), wherein the layer contains 10 to 60% by mass of a polypropylene-based resin. (7) The film according to any one of (1) to (6), wherein the layer 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), 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. (9) The film according to any one of (1) to (8), wherein the film 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, and the circular stage 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.

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

[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) 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), is 5.0 or more; and (b) the static friction coefficient of at least one outermost layer 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 layers may be the same or different from each other. 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 each other, 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 each other" means that at least one of the material and thickness of each layer is different from each other.

[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 and 50°C at an amplitude strain of 0.05% and 10 Hz, that is, the ratio of the storage modulus E'(0) to the storage modulus E'(50) at 50°C, 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 the method 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 excellently stretched on the upper surface of the processing device stage when used in the expanding process, which is 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] [Having a tan δ peak at 5 to 50°C, with the peak value being 0.15 or greater] One 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, with the peak value being 0.15 or greater. Here, the tan δ peak refers to the maximum value of the loss tangent (tan δ) measured by DMA (dynamic mechanical analysis), 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 mechanical analysis) as 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 becomes large, and E'(0) / E'(50) can be preferably controlled. Furthermore, by controlling the peak value of the tan δ peak of the film of the present invention at 5 to 50°C to 0.15 or more, the degree of decrease in storage modulus becomes large, and E'(0) / E'(50) can be more preferably controlled, thereby maintaining the elongation during the dicing process and improving the cuttability when cutting the film in each process.

[0017] A preferred method for controlling the tan δ peak of the film of the present invention to be in 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 (or the entire film if it is a single layer) among the layers contained in the film of the present invention. 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. As the styrene-based elastomer, 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 hydrogenated products thereof (e.g., styrene-ethylene-butadiene-styrene copolymer (SEBS)), and styrene-isobutylene copolymers (e.g., styrene-isobutylene-styrene triblock copolymer (SIBS), styrene-isobutylene diblock copolymer (SIB), and styrene-isobutylene block copolymers such as mixtures thereof) are preferably used. When the styrene elastomer has a tan δ peak in the range of 5 to 50° C., the styrene elastomer alone may be used as the resin for controlling E'(0) / E'(50), or when the tan δ peak of the styrene elastomer is less than 5° C., it is preferable to use the styrene elastomer in combination with a softener for adjusting the tan δ 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. and used in at least one of the thickest layers contained in the film of the present invention (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 softener, or mixed resins of SIB and / or SIBS with the softener.

[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 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 it is more preferable to use one or more polypropylene-based resins selected from the group consisting of homopolypropylene, random copolymers of propylene and ethylene and / or butene-1, block polypropylene, propylene-α-olefin copolymers, propylene-ethylene-α-olefin copolymers, etc. Furthermore, it is preferable that E'(0) is 4000 MPa or less.

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

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

[0024] [Having a melting point of 40 to 80° C.] Another preferred embodiment in which E′(0) / E′(50) is controlled to be 5.0 or more is an embodiment 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 of 0.5 or Less] The static friction coefficient between at least one surface of the film of the present invention is 0.5 or less. 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 case, if friction between the surface of the circular stage or the outer edge of the film and the film 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 is reduced when expanding the dicing film using the film of the present invention, 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 applying a embossing treatment or a lubricant coating treatment to at least one surface can be preferably used.

[0029] As described above, the film of the present invention preferably contains at least one layer containing a resin, and may be composed of one layer (i.e., a single layer) 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, a resin layer A and a resin layer B described below. It may be a two-layer film of 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 structures include a three-layer structure having, in this order, a resin layer B, a resin layer A, and a resin layer C described below; a three-layer structure having, in this order, a resin layer B, a resin layer A, and a resin layer D described below; and a four-layer structure having, in this order, a resin layer B, a resin layer A, a resin layer C, and a resin layer D.

[0030] [Surface indentation hardness of 33 MPa or more and 150 MPa or less] The film of the present invention preferably has an indentation hardness of at least one surface of 33 MPa or more and 150 MPa or less in a load-unloading test by 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, when expanding a dicing film using the film of the present invention, 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 suppressed, 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 cuttability during the film 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: 0.2 μm or More and 2.0 μm or Less] As mentioned above, during the semiconductor chip expanding process, friction occurs between the film and the upper surface or peripheral edge of the circular stage. In particular, at the peripheral edge (near the corners) of the stage, the film is likely to be pressed strongly against the stage due to the stage's thrust. If the height of the convex structure on the film surface that contacts the circular stage upper surface is too large, localized friction increases and slippage may be impaired. Furthermore, if the convex structure on the film surface is too small, the contact area between the stage and the 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, an increase in the contact area between the stage and the film surface is suppressed, improving the slipperiness, and further enabling the film on the stage surface to be stretched more sufficiently.

[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, it is more preferable that Spk is 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 surface of the film 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. These will be described later.

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

[0040] [Kurtosis Sku of 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 (normal distribution) with respect to the mean plane, and when Sku exceeds 3, the height distribution has a peaked shape, while when Sku is less than 3, the height distribution tends to have a flat shape.

[0041] As described above, during the semiconductor chip expansion process, friction occurs between the film and the upper surface or peripheral edge of the circular stage. In particular, the film is likely to be pressed strongly against the stage at the peripheral edge (near the corners) of the stage due to the stage being pushed up. When 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, which may impair slipperiness. By setting Sku to 3.0 or more, 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, from the viewpoint of preventing excessive deformation of the surface shape when a load is applied to the film surface and preventing a decrease in slipperiness during the expansion process, Sku is preferably 40 or less, more preferably 10 or less.

[0042] The Sku is in accordance with the ISO standard 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. Examples include 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 Sku is 3.0 or more on the surface where the coefficient of static friction between the two surfaces is 0.5 or less. The Sku is preferably 40 or less, and more preferably 10 or less.

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

[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 and 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 film 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 tear 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 a layer 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 (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 appropriately adjusted 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 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 be reduced. 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, even more preferably 60% or more. Furthermore, 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 polyolefins and polyesters can be used, but it is more preferable to use polyolefins as the main component from the viewpoints of environmental considerations, productivity, processability, etc. Here, "using polyolefins as the main component" means that the proportion of polyolefins is 50% by mass or more, more preferably 70% by mass or more, when the entire resin layer A is taken as 100% by mass.

[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 the above-mentioned 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 containing at least a resin, and is a layer 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, the surface shape (Spk, Sku) and surface hardness of resin layer B, which will be described later, can be controlled by adjusting the material constituting resin layer B and the production conditions, eliminating the need for processes such as embossing and lubricant coating, thereby improving productivity.

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

[0055] For the resin layer B, the same resins as the polyolefins suitable for the resin layer A described above can be preferably used. Among these, from the viewpoint of improving productivity, processability, and the lubricity of the film of the present invention, there can be 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 are a method using block polypropylene, a method using two or more incompatible resins in resin layer B, and a method containing inorganic or organic particles in resin layer B. Furthermore, from the viewpoint of suppressing process contamination due to particle shedding during processing, a method using two or more incompatible resins in resin layer B is even more preferred. In the method using two or more incompatible resins, it is 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 two or more incompatible resins are used in resin layer B and Spk and Sku are controlled by the combination of resins, they can be controlled by the difference in melt viscosity at the temperature at which extrusion is performed, 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 by nanoindentation. As a method for controlling the indentation hardness within the above-mentioned range and enhancing the lubricity, 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) which is incompatible with the polypropylene-based resin b.

[0062] When polypropylene-based resin b and high-density polyethylene are used in combination in resin layer B, the proportion of polypropylene-based resin b used in resin layer B 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), when the entire resin layer B is taken as 100% by mass. 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 the polypropylene resin b and high-density polyethylene are used in combination in the resin layer B, in order to improve the Spk to 0.2 μm or more, the resin layer B is heated at 230° C. and a shear rate of 122 s －１ Similarly, from the viewpoint of controlling the Spk to 2.0 μm or less, 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 －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 thickness of all layers of the film of the present invention is 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 homocopolymers, 1-butene-ethylene copolymers, 1-butene-propylene copolymers, 4-methylpentene-1 homocopolymers, 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 suppressing cutting debris during dicing, propylene elastomers and 1-butene elastomers are more preferable, and propylene elastomers are particularly preferable.

[0069] 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 the 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 the 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 the resin layer C is less than 10%, the film of the present invention may become thin-film laminated during film formation, making production more difficult, or the cuttability that is the effect of the resin layer C may not be fully exhibited. Furthermore, if the layer structure of the resin layer C exceeds 25%, the elongation of the film of the present invention may be insufficient.

[0071] [Resin Layer D] In addition to the resin layer A, resin layer B, and resin layer C, the film of the present invention may have a resin layer D having adhesive properties 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 (for example, styrene-ethylene-butadiene-styrene copolymer (SEBS)), and styrene-isobutylene copolymers (for example, 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 copolymer; 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 can preferably be 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 imparting 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 for example, in the case of 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 then 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, but production by the coextrusion method is preferred from the viewpoint of productivity. As the coextrusion method, known methods such as an inflation method and a T-die method can be used, but from the viewpoint of excellent thickness accuracy and surface shape 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.

[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) Film Storage Modulus E' and Loss Tangent tanδ Measurement samples were cut into 10 mm wide rectangles to form test pieces. Based on the tensile vibration-non-resonance method of JIS K7244-4 (1999) (referred to as the dynamic viscoelasticity method), 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), respectively, and the storage modulus at each temperature was determined. E'(0) / E'(50) was also calculated. Regarding 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 in the range of 5 to 50°C, this was indicated as "-" in Tables 1 and 2. Measurement mode: tension; Test piece width: 5 mm; Frequency: 10 Hz; Amplitude distortion: 0.05%; Measurement temperature: -50°C to 100°C; Heating rate: 3°C / min.

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

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

[0084] (3) Measurement of melting point According to 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) at a rate of 20 ° C. / min to obtain a differential scanning calorimeter chart. From the obtained differential scanning calorimeter chart, the melting peak temperature was determined based on the method described in JIS K-7121 (1987), and the presence or absence of a melting peak temperature (melting point) at 40 to 80 ° C. and the temperature were confirmed. In addition, if a melting peak temperature (melting point) was not observed at 40 to 80 ° C., it was indicated as "-" in Tables 1 and 2.

[0085] (3-2) Crystallization Temperature of Resin According to JIS K-7121 (2012), the resins used in the examples and comparative examples were measured using a differential scanning calorimeter (Rigaku Thermo plus EVO2 DSCvesta) under the following conditions, and the crystallization temperature was determined from the differential scanning calorimetry curve obtained in step (iii). Sample amount: 3 mg Heating rate, cooling rate: 20°C / min Temperature program: Step (i) Heat from 30°C to 250°C, Step (ii) Hold at 250°C for 5 minutes, Step (iii) Cool 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 the resin layer B, the resin layer A, and the resin layer C were measured.

[0087] (5) Evaluation of expandability (elongation, uniform stretchability) A sample was cut out to a size of 300 mm × 200 mm so that the film production line direction (MD) of the measurement sample was the longitudinal direction. 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 contacted the surface on the stage of an expander (manufactured by Hugle) and the printed grid overlapped on 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 in the film production line direction (MD) and the perpendicular direction (TD) was calculated to evaluate the expandability. The elongation at 20 points in each of the MD and TD was calculated, and the average value in the MD and TD 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: 40 mm Stage temperature: 25°C

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

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

[0091] (6) Evaluation of Cuttability a When the sample film was cut with a cutter knife in an atmosphere of 23°C and 65% RH, 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. B or higher is within the practical range. A: A smooth cut was possible. B: A relatively good cut was possible. C: After cutting, notches or whiskers appeared on the cross section, and in some cases the sample stretched.

[0092] (6-2) Evaluation of Cutting Ability 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 Layer A side using an OLFA rotary compass cutter. The condition of the cut circumference was visually observed to check for cutting defects such as notches, whiskers, and film stretching, and the cutting ability of the film was evaluated according to the following criteria. The blade was replaced with a new one after each measurement. A: Cutting defects occurred in less than one-eighth of the circumference. B: Cutting defects occurred in less than one-quarter of the circumference. C: Cutting defects occurred in less than one-third of the circumference. D: Cutting defects occurred in less than two-fifths of the circumference. E: Cutting defects occurred in two-fifths or more of the circumference.

[0093] (7) Loss tangent tanδ of elastomer Samples were prepared by melt-molding pellets of the elastomer used in the examples to a thickness of 1 mm. Measurements were performed using a rheometer AR2000ex manufactured by TA Instruments, Inc. 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 tanδ was evaluated during the heating process.

[0094] (8) Indentation Hardness An indentation test was performed on the surface of the resin layer B using a nanoindentation tester ENT-2100 manufactured by Elionix under the following conditions: A random point was used as the base point for one type of film, and measurements were taken at 1 mm intervals in the cross direction in the MD and TD directions, three points on each side (13 points in total) from this base point (13 points in total). Of the obtained indentation hardness values, the average of six measurements, excluding the top two and bottom two points, was taken as the indentation hardness of the surface of the resin layer B. Indenter: Berkovich indenter manufactured by Elionix (triangular pyramid tip, made of diamond) Temperature: 23 ° C Maximum load: 0.10 mN Loading rate / unloading rate: 0.01 mN / s Load at the start of the load-unloading test: 0 mN Holding time at maximum load: 1 second Surface detection method: Inclined method Surface detection threshold coefficient: 1.5 Spring correction: Real-time spring correction.

[0095] (9) Spk, Sku The surface of the resin layer B was measured using a scanning white light interference microscope (VS1540) manufactured by Hitachi High-Tech Science Corporation in accordance with ISO25178-2 (2012) under the following conditions and device configuration, and the photographed image was subjected to a complementary process (complete complement) using the attached analysis software below. After surface correction using a polynomial quartic approximation, the protruding peak height Spk (μm) and kurtosis Sku were obtained by processing with a median filter (3 × 3 pixels). Five measurements were performed for each type of film, and the arithmetic mean value of the five Spk (μm) values ​​was taken as the film's Spk (μm). Similarly, the arithmetic mean value of the five Sku values ​​was taken as the film's Sku.

[0096] <Measurement conditions and device configuration> Objective lens: 10x Lens tube: 1x Zoom lens: 1x Wavelength filter: 530 nm 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 (a total of four fields of view, 2 fields of view x 2 fields of view, were connected to measure the above range) Number of pixels: 1842 x 1844.

[0097] (10) Melt viscosity: Using a Capillograph (1D) manufactured by Toyo Seiki Seisakusho, the temperature was 230°C and the shear rate was 122 s －１The 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 having a melt viscosity of 410 Pa·s, a crystallization temperature of 113°C, and a melting point of 165°C.

[0101] <RPP> Commercially available metallocene 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 of 1090 Pa s, a crystallization temperature of 116°C, a melting point of 136°C, and a density of 0.960 g / cm ３ 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 Commercially available high-density polyethylene <LLDPE-1>: Trade name "Evolue" (registered trademark) SP0540, manufactured by Prime Polymer Co., Ltd. Melt viscosity: 780 Pa s, density: 0.904 g / cm ３ , MFR 3.8 g / 10 min (measured at 190°C).

[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 3.8 g / 10 min (measured at 190°C).

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

[0104] <TPE-2> PP elastomer, trade name "Toughmer" (registered trademark) PN2060, manufactured by Mitsui Chemicals, Inc., density 0.868 g / cm ３, MFR 6.0 g / 10 min (measured at 230°C).

[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 10 g / 10 min (measured at 230°C), 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 "Absoutomer" (registered trademark) EP-1001, manufactured by Mitsui Chemicals, Inc. MFR 10 g / 10 min (measured at 230°C), tan δ peak temperature 32°C, tan δ (32°C) 2.4.

[0107] <TPE-5> Styrene-based elastomer, product name "S.O.E." S1605, Asahi Kasei, density 1.0 g / cm ３ , MFR 5g / 10min (measured at 230°C), tan δ peak temperature 16°C, tan δ (16°C) 1.3.

[0108] <PB> Trade name "Tafmer" (registered trademark) BL4000, manufactured by Mitsui Chemicals, Inc. MFR 1.8 g / 10 min (measured at 190°C).

[0109] <PE Particle Masterbatch (PE Particle MB)> A polyethylene particle masterbatch consisting of high-molecular-weight polyethylene particles "Mipelon" (registered trademark) PM200 manufactured by Mitsui Chemicals, Inc. and having an average particle diameter of 10 μm and metallocene-based linear low-density polyethylene ("Evolue" (registered trademark) SP2040 manufactured by Prime Polymer Co., Ltd., MFR 3.8 g / min (measured at 190°C and 21.17 N)) in a mass ratio of 10:90 was prepared.

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

[0111] Examples 3 to 6 The constituent resins of each layer shown in Table 1 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 extruders with diameters of 115 mm (for resin layer A), 90 mm (for resin layer C), and 65 mm (for resin layer B). The output rate 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%. Each film was extruded from the composite T-die at an extrusion temperature of 200°C to form a three-layer film having a film thickness of 80 μm and a resin layer B / resin layer A / resin layer C configuration.

[0112] Examples 7 to 14, 16 to 31 Three-layer films having a resin layer B / resin layer A / resin layer C configuration were 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 configuration was formed in the same manner as in Examples 3 to 6, except that the constituent resins of each layer shown in Table 3 were used, and then the surface of resin layer B (commercially available metallocene-based random polypropylene having a melt viscosity of 510 Pa s, a crystallization temperature of 101°C, and a melting point of 136°C, a 100% surface) was hot-pressed with an embossing roll to apply a graining treatment.

[0114] Comparative Example 1 The constituent resins of each layer shown in Table 5 were fed into each extruder of a multi-manifold T-die composite film-forming machine having a nozzle width of 2,400 mm and having two extruders consisting of a φ115 mm (for resin layer A) and a φ90 mm (for resin layer C). The output rate 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 two-layer films with a film thickness of 80 μm.

[0115] Comparative Examples 2 and 3 The constituent resins of each layer shown 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 extruders with diameters of 115 mm (for resin layer A), 90 mm (for resin layer C), and 65 mm (for resin layer B). The output rate 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 having a film thickness of 80 μm and a resin layer B / resin layer A / resin layer C configuration was formed.

[0116]

[0117]

[0118]

[0119]

[0120]

Claims

1. The following (a) and (b) are satisfied: A film having an indentation hardness of at least one surface of 33 MPa or more and 150 MPa or less in a load-unloading test using nanoindentation. (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. 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, comprising 5 to 60% by mass of a styrene-based elastomer and / or a 4-methyl-1-pentene·α-olefin copolymer.

7. 3. The film according to claim 1 or 2, which contains 10 to 60% by mass of a polypropylene-based resin relative to 100% by mass of the resin constituting the entire film, 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.

8. 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.

9. The film according to claim 1 or 2, having a melting point of 40 to 80°C.

10. The film according to claim 1 or 2, which is for use in wafer dicing.