TW201841738A - Film and method for producing film - Google Patents

Abstract

A film characterized by having a stress at 5% elongation at 25 DEG C, Ta, of 1.0-20.0 MPa. In cases when dimensional change at 90 DEG C during heating from 25 DEG C to 160 DEG C at a rate of 10 DEG C/min under a load of 120 g/mm2 is referred to as 90 DEG C dimensional change 1 and when the direction in which the 90 DEG C dimensional change 1 is maximum is referred to as X direction, the direction which is perpendicular to the X direction within the plane of the film is referred to as Y direction, and the X-direction 90 DEG C dimensional change is expressed by T*1 (%), then the film is characterized in that T*1 is -10.00% or greater but not greater than 10.00%. The film has both heat resistance sufficient for maintaining the flatness in heating steps and flexibility sufficient for uses as a dicing pressure-sensitive adhesive film, etc., and is suitable for use as a substrate for semiconductor production steps.

Description

   Film, and method for manufacturing film   

The present invention relates to a thin film and a method for manufacturing the thin film.

Conventionally, a variety of products, such as substrates for adhesive tapes, transfer substrates for molding, and cushioning materials under pressure, have been applied to film members with high flexibility that can be stretched at a low load at room temperature. As a use, it is also used in a wide range of fields such as circuit or semiconductor manufacturing or decoration.

For example, in the step of manufacturing a semiconductor, there is a step of attaching an adhesive tape for semiconductor wafer processing on a pattern surface of a semiconductor wafer, and a backside polishing step of polishing the back surface of the semiconductor wafer to reduce the thickness, Various steps such as the step of mounting the semiconductor wafer with the reduced thickness to the dicing tape, the step of peeling the aforementioned adhesive tape for semiconductor wafer processing from the semiconductor wafer, and the step of dividing the semiconductor wafer by dicing, etc. step.

In recent years, with the miniaturization of electronic devices, the thinning of semiconductor wafers has progressed. Due to their reduced strength, there are problems in these processes that they are easily damaged and yields are reduced. For example, after the dicing step, the dicing adhesive film is expanded into a radial shape, and in the step of picking up each wafer, an adhesive film having excellent softness to reduce the load on the semiconductor wafer is required. In addition, as a method for improving the flexibility of an adhesive film, for example, a film containing a polypropylene-based resin, an olefin-based elastomer, a styrene-based elastomer, or the like having excellent flexibility as a main component is known as a base of the adhesive film Method of thin film (Patent Document 1).

In addition, there is a step of bonding the adhesive film for dicing to the semiconductor wafer surface polished by the back surface polishing step, and peeling the back surface polishing sheet by thermal peeling. At that time, if the dimensional stability of the adhesive film for cutting that was heated simultaneously was insufficient, the film was deformed and wrinkles or sagging occurred. For such problems, for example, as a base material of an adhesive film for a dicing tape, a film having controlled heat shrinkage has been proposed (Patent Document 2).

    [Prior technical literature]         [Patent Literature]    

Patent Document 1: Japanese Patent Application Laid-Open No. 2011-119548

Patent Document 2: Japanese Patent Application Laid-Open No. 2014-157964

However, since the base material for the adhesive tape described in Patent Document 1 or Patent Document 2 is an unstretched film obtained by an extrusion method, there is a problem in that it expands under the application of tension and loses the flatness of the film. In addition, in the past, a non-stretched film used as a base film such as an adhesive film for dicing has been difficult to apply to semiconductor process applications because the film expands when heated under a low load. On the other hand, films with high dimensional stability, such as biaxially stretched films, have reduced flexibility during heating, but have insufficient flexibility. Therefore, it is similarly difficult to apply them to this application. As described above, conventional films cannot have both the heat resistance and flexibility required for a substrate for a semiconductor process, and improvements are desired.

The object of the present invention is to provide a film suitable as a substrate for a semiconductor process, which eliminates the problems of the conventional technology, has heat resistance to such an extent that it can maintain flatness in the heating step, and is used as an adhesive film for cutting. Fully soft.

To solve such a problem, the present invention includes the following configurations.

(1) A film characterized by a stress Ta of 1.0 MPa or more and 20.0 MPa or less at 5% stretching at 25 ° C, a load of 120 g / mm ² is applied, and a temperature of 10 ° C / min is applied from 25 ° C to 160 ° C. The rate of dimensional change at 90 ° C during temperature rise is regarded as the dimensional change rate 1 at 90 ° C. The direction in which the dimensional change rate 1 at 90 ° C is maximized is taken as the X direction, and the direction orthogonal to the X direction in the film plane is taken as When the 90 ° C dimensional change rate in the X direction is taken as Tx1 (%) in the Y direction, Tx1 is -10.00% or more and 10.00% or less.

(2) The film according to (1), in which a load of 5 g / mm ² is applied, and the dimensional change rate at 90 ° C. when the temperature is raised from 25 ° C. to 160 ° C. at a heating rate of 10 ° C./min is regarded as the 90 ° C. size When the change rate 2 is 90% of the dimensional change rate 2 in the X direction as Tx2 (%), Tx2 is -10.00% or more and 1.00% or less.

(3) The film according to (1) or (2), wherein the surface alignment coefficient on at least one side is 0.0080 or more and 0.0800 or less.

(4) The film according to any one of (1) to (3), wherein when the layer having a glass transition temperature of -40 ° C or higher and 40 ° C or lower is used as the A layer, the layer has one or more A layers.

(5) The film according to any one of (1) to (4), wherein when the 90 ° C dimensional change rate 1 in the Y direction is taken as Ty1 (%), the Tx1 and Ty1 satisfy the following formula 1; 1: 0.10 ≦ | Tx1-Ty1 | ≦ 3.00.

(6) The film according to any one of (1) to (5), wherein the static friction coefficient measured on the different surfaces of the laminated film is 0.10 or more and 0.80 or less.

(7) The film according to any one of (1) to (6), which is on at least one side, and the surface roughness SRa (μm) and ten-point average roughness SRzjis (μm) satisfy the following formula 2; Formula 2: 5.0 ≦ SRzjis / SRa ≦ 25.0.

(8) (1) to (7) according to any one of the thin film, wherein the heat shrinkage stress of the X direction and the Y direction of 90 deg.] C was 0.010N / mm ² or more 5.000N / mm ² or less.

(9) The film according to any one of (1) to (8), wherein the shrinkage rate after heating at 80 ° C for 1 hour exceeds 1.00% and is 10.00% or less.

(10) The film according to any one of (1) to (9), wherein the above-mentioned Ta and the stress Tb at 5% extension at 25 ° C after heating at 90 ° C for 10 minutes satisfy the following formula 3; formula 3: 0.85 ≦ Tb / Ta ≦ 1.30.

(11) The film according to any one of (1) to (10), wherein the maximum stress Ka after 50% elongation at 25 ° C and the stress Kb at 50% elongation satisfy the following formula 4; formula 4: 0.70 ≦ Kb /Ka≦1.00.

(12) The film according to any one of (1) to (11), wherein the 90 ° C dimensional change rate 1 in all directions is -25.00% or more and 10.00% or less.

(13) The film according to any one of (1) to (12), wherein the 90 ° C dimensional change rate 2 in all directions is -25.00% or more and 1.00% or less.

(14) The thin film according to any one of (1) to (13), wherein the number of adhered foreign matter having a diameter of 100 μm or more is 10 pieces / m ² or less.

(15) The film according to any one of (1) to (14), whose thickness is not all 10.0% or less

(16) A method for manufacturing a film, which is the method for manufacturing a film according to any one of (1) to (15), characterized in that it has a magnification of 1.04 times or more and 2.00 times or less and extends in at least one direction The steps.

According to the present invention, a thin film having both flexibility and heat resistance and a method for manufacturing the same can be provided. The thin film of the present invention can be suitably used as a substrate for a semiconductor process.

    [Form of Implementing Invention]    

The film of the present invention is characterized in that the stress Ta at 5% stretch at 25 ° C is 1.0 MPa or more and 20.0 MPa or less, a load of 120 g / mm ² is applied, and the temperature rise rate is from 10 ° C./min to 25 ° C. to 160 ° C. The dimensional change at 90 ° C when heating is regarded as the dimensional change rate 1 at 90 ° C, the direction in which the dimensional change rate 1 at 90 ° C becomes the largest is the X direction, and the direction orthogonal to the X direction in the film plane is the Y direction. When the 90 ° C dimensional change rate in the X direction is taken as Tx1 (%), Tx1 is -10.00% or more and 10.00% or less.

In the film of the present invention, from the viewpoints of improvement in heat resistance and reduction of wafer flaws in a semiconductor process, it is important that the stress Ta at 25 ° C during 5% stretching is 1.0 MPa to 20.0 MPa. If the stress Ta (hereinafter, also simply referred to as Ta) at 5% extension at 25 ° C is less than 1.0 MPa, the film will deform during heating due to the quality of the semiconductor wafer, or it will deform unevenly when expanding the film. On the other hand, if Ta is larger than 20.0 MPa, the load when picking up the wafer is large, and the wafer is damaged. From the above viewpoint, Ta is more preferably 1.5 MPa to 15.0 MPa, and even more preferably 2.0 MPa to 10.0 MPa. The method for making Ta into the above range is not particularly limited, and examples thereof include a casting film having a glass transition temperature of at least one layer or more and a temperature of -50 ° C or more and 50 ° C or less. Method, or a method of extending the cast film in at least one direction at a magnification of 2.00 times or less.

The "stress at 5% extension at 25 ° C Ta" refers to the stress at 5% extension at 25 ° C measured at a test speed of 300 mm / min in accordance with JIS K7127 (1999, test piece type 2). In addition, the so-called "stress Ta at 5% elongation at 25 ° C is 1.0 MPa or more and 20.0 MPa or less" means that an arbitrary direction parallel to the film surface is regarded as a 0 ° direction, and from 0 ° direction parallel to the film surface When the right-handed 175 ° rotation direction is taken as the 175 ° direction, the test speed is 300mm / min in the range of 0 ° to 175 ° at 5 ° intervals in accordance with JIS K7127 (1999, test piece type 2). Measure the stress at 5% elongation at 25 ° C. The maximum value of the 36 batches obtained is 1.0 MPa or more and 20.0 MPa or less. In addition, the evaluation sample was a rectangular shape of 150 mm (measurement direction) x 10 mm (direction orthogonal to the measurement direction).

When the film of the present invention is subjected to a load of 120 g / mm ² and the temperature is increased from 25 ° C. to 160 ° C. at a temperature increase rate of 10 ° C./min, the dimensional change at 90 ° C. is regarded as the 90 ° dimensional change rate 1, and 90 ° C. The direction in which the dimensional change rate 1 becomes the largest is regarded as the X direction, the direction orthogonal to the X direction in the film plane is regarded as the Y direction, and the 90 ° C dimensional change rate in the X direction is regarded as Tx1 (%). Tx1 is -10.00% or more and 10.00% or less. Since Tx1 is set to the said range, the deformation | transformation at the time of heating can be reduced in the state which laminated semiconductor wafer and applied the elongation load to a thin film. If Tx1 is less than -10.00%, wrinkles may occur due to the shrinkage of the film, and if Tx1 is more than 10.00%, the fixed position of the semiconductor wafer may be changed due to the expansion of the film, and a defective condition may occur in subsequent steps. Based on the above viewpoint, Tx1 is preferably -10.00% or more and 1.00% or less, more preferably -8.00% or more and 1.00% or less, and even more preferably -4.50% or more and 1.00% or less.

When the film of the present invention is applied with a load of 5 g / mm ² and the temperature is increased from 25 ° C. to 160 ° C. at a temperature increase rate of 10 ° C./min, the dimensional change at 90 ° C. is regarded as the 90 ° C. dimensional change rate 2 and the aforementioned X When the 90 ° C dimensional change rate 2 in the direction is taken as Tx2 (%), Tx2 is preferably -10.00% or more and 1.00% or less. Since Tx2 is set to the said range, even if the load applied to a film is small, the deformation | transformation by heating can be reduced. By setting Tx2 to -10.00% or more, the occurrence of wrinkles due to film shrinkage can be reduced. In addition, by setting Tx2 to 1.00% or less, it is possible to reduce the occurrence of a defect in a subsequent step due to a change in the fixed position of the semiconductor wafer due to the expansion of the film. Based on the above point of view, Tx2 is more preferably -8.00% or more and 0.00% or less, and particularly preferably -4.50% or more and 1.00% or less.

The "90 ° C dimensional change rate 1" can be measured by the following procedure. First, a thin film sample of 15 mm (measurement direction) x 4 mm (direction orthogonal to the measurement direction) is cut at room temperature, and the sample is left to stand for 24 hours under the environment of a temperature of 25 ° C and a relative humidity of 65%. The length (L ₀ ) in the measurement direction. Next, this film sample was heated from 25 ° C to 160 ° C under a load of 120 g / mm ² at a temperature increase rate of 10 ° C / min, and the length (L ₁ ) in the measurement direction at 90 ° C was measured. From the obtained values of L ₀ and L ₁ , the 90 ° C dimensional change rate 1 was determined by the following Equation 5.

Formula 5: Size change rate 90 ℃ 1 (%) = ( L 1 -L 0) × 100 / L 0.

The device used for the measurement for calculating the size at 90 ° C. dimensional change rate 1 is not particularly limited as long as the effect of the present invention is not impaired. For example, a thermal analysis device TMA / SS6000 (manufactured by SEIKO Instruments Corporation) can be used. In the X direction, the 90 ° C dimensional change rate 1 in any direction parallel to the film surface is measured. Thereafter, it is rotated parallel to the film surface and rotated right every 5 ° until the angle from the direction originally selected reaches 175 °. When the 90 ° C dimensional change rate 1 is taken as the direction in which the value of the 90 ° C dimensional change rate 1 is the largest. Then, the value of the dimensional change rate 1 at 90 ° C at that time was taken as Tx1 (%). Here, "the value of the dimensional change rate 1 at 90 ° C is the largest" means that the value of the dimensional change rate 1 at 90 ° C obtained by Expression 5 is the largest. For example, if the measured 90 ° C dimensional change rate 1 in the entire direction is in the range of -5.00% to 3.00%, the direction in which the 90 ° C dimensional change rate 1 is 3.00% becomes the X direction.

However, when the direction at which the value of the 90 ° C dimensional change rate 1 obtained by Equation 5 is the largest exists, the values of the 90 ° C dimensional change rate 1 from each measurement direction are respectively calculated and subtracted from each measurement direction. The absolute value of the value obtained from the 90 ° C dimensional change rate 1 in the direction of intersection can be regarded as the X direction with the smallest direction within the range of 0.10% to 3.00%. When the absolute value is outside the range of 0.10% to 3.00% in any of the measurement directions, the direction in which the absolute value is closest to the range of 0.10% to 3.00% is regarded as the X direction.

The "90 ° C dimensional change rate 2" refers to the dimensional change rate measured by the same method as the 90 ° C dimensional change rate 1 except that the magnitude of the load is set to 5 g / mm ² . The same apparatus as the 90 ° C dimensional change rate 1 was used.

The method of making Tx1 from -10.00% to 10.00% or less or the above-mentioned preferable range is not particularly limited as long as the effect of the present invention is not impaired. For example, a method having at least one glass transition temperature of -50 ° C to 50 ° C is mentioned. The method of extending the cast film of the following layers in at least one direction at a magnification of 1.04 times or more and 2.00 times or less. The method for making Tx2 equal to or more than -10.00% and not more than 1.00% or the above-mentioned preferred range is not particularly limited as long as the effects of the present invention are not impaired. A method of extending in at least one direction at a magnification of 1.04 times or more and 2.00 times or less.

The value of the 90 ° C dimensional change rate 1 in directions other than the X direction is not particularly limited as long as the effect of the present invention is not impaired. However, from the viewpoint of reducing the dimensional change during heating under an applied load, the 90 ° C dimensional change rate 1 in all directions is preferably -25.00% or more and 10.00% or less, more preferably -15.00% or more and 1.00% or less, and particularly preferably It is above -10.00% and below 1.00%. By adopting such a configuration, when the semiconductor wafer is heated while an elongation load is applied to the film, excessive deformation of the film is suppressed, and thus it is possible to easily achieve necessary dimensional stability in a semiconductor process.

The value of the 90 ° C. dimensional change rate 2 in directions other than the X direction is not particularly limited as long as the effect of the present invention is not impaired. However, from the viewpoint of reducing the dimensional change during heating even when the load applied to the film is small, the 90 ° C dimensional change rate 2 in all directions is preferably -25.00% or more and 1.00% or less, and more preferably -15.00% or more. 0.00% or less, particularly preferably -10.00% or more and 1.00% or less. By adopting such a state, even when the semiconductor wafer is laminated and heated with a small load applied to the thin film, the excessive deformation of the thin film is suppressed, so that necessary dimensional stability can be easily achieved in a semiconductor process.

The film alignment coefficient of at least one surface of the film of the present invention is preferably 0.0080 or more and 0.0800 or less. The surface alignment coefficient is an index indicating the degree of alignment of the polymer in the film surface. The larger the surface alignment coefficient, the higher the alignment state. The surface alignment coefficient (fn) referred to here means the surface alignment coefficient measured by the following method. First, let any direction parallel to the film surface be α, let the direction orthogonal to the film surface be β, and the direction (thickness direction) orthogonal to α and β be γ. Measure the refractive index (nα, nβ, nγ) in each direction. Using the obtained values, the surface alignment coefficients (fn ₀ ) when the two directions on the film surface are α and β are obtained by the following Equation 6.

Formula 6: fn ₀ = (nα + nβ) / 2-nγ.

Next, γ is fixed. While maintaining the parallelism of α and β to the film surface, they are rotated right every 5 ° to become nα5 and nβ5. The refractive index (nα5, nβ5) in each direction is measured with an Abbe refractometer. , Nγ), where nα in Equation 6 is replaced by nα5, and nβ is replaced by nβ5, and the surface alignment coefficients (fn ₅ ) when the two directions on the film surface are α5 and β5 are obtained. Hereinafter, the same measurement is repeated in the same manner until the two directions on the film surface become α85 and β85. The average value of the measured values of the obtained 18 batches of fn ₀ to fn _{85 is} the surface alignment coefficient (fn).

When the surface alignment coefficient is less than 0.0080, that is, a film having no orientation or very close to the state without orientation, although the flexibility is sufficient, the heat resistance is poor. On the other hand, if the surface alignment coefficient exceeds 0.0800, the degree of alignment becomes high and the heat resistance is excellent, but the flexibility becomes insufficient. From the viewpoint of considering the flexibility and heat resistance of the film, the film alignment coefficient of at least one surface of the film of the present invention is preferably 0.0120 or more and 0.0600 or less, and more preferably 0.0150 or more and 0.0400 or less.

The method for setting the surface alignment coefficient of at least one side of the film of the present invention to be 0.0080 or more and 0.0800 or less or the above-mentioned preferable range is not particularly limited as long as the effect of the present invention is not impaired. A method in which the magnification is greater than or equal to 2.00 times and extended in at least one direction. By stretching at such a low magnification, it is possible to orient the molecules of the resin to such an extent that the flexibility of the film is not impaired. Based on the above viewpoint, when extending in a direction more than biaxial, the area extension ratio obtained by multiplying the extension ratio in each direction is preferably 1.20 times or more and 1.80 times or less, and more preferably 1.40 times or more and 1.70 times or less.

In the film of the present invention, when a layer having a glass transition temperature of -40 ° C to 40 ° C is used as the A layer, it is preferable to have at least one layer of A. Due to the A layer, the film has sufficient flexibility even at room temperature. In addition, by combining with an extension described later at a magnification of 1.04 times or more and 2.00 times or less, the alignment state of the molecules can be controlled within an appropriate range of flexibility and heat resistance that can achieve the object of the present invention. The glass transition temperature referred to here is a temperature obtained based on the measurement of thermal change (DSC method) of differential scanning calorimetry (DSC) in accordance with JIS K7121 (2012). From the viewpoint of considering both flexibility and heat resistance, the glass transition temperature of the layer A is preferably -25 ° C or higher and 20 ° C or lower, and more preferably -10 ° C or higher and 5 ° C or lower.

The resin used in the film of the present invention is not particularly limited as long as the effects of the present invention are not impaired. For example, polyethylene terephthalate (PET), polybutylene terephthalate ( PBT), polyesters such as polyethylene naphthalate (PEN), polyarylate, polyethylene, polypropylene, polyamide, polyimide, polymethylpentene, polyvinyl chloride, polystyrene , Polymethyl methacrylate, polycarbonate, polyetheretherketone, polyfluorene, polyetherfluorene, fluororesin, polyetherfluorine imine, polyphenylenesulfide, polyurethane, and cyclic olefin resin use. Among them, polyesters, polypropylene, and the like, such as polyethylene terephthalate or polybutylene terephthalate, are more preferably used from the viewpoints of handling, dimensional stability, and economical efficiency at the time of production of the film. Of polyolefins.

The so-called polyester in the present invention is a general term for polymers whose main bonds in the main chain are ester bonds. Generally, a polyester system is obtained by subjecting a dicarboxylic acid component and a diol component to a polycondensation reaction.

The dicarboxylic acid component used to obtain the polyester is not particularly limited as long as the effects of the present invention are not impaired. For example, terephthalic acid, isophthalic acid, phthalic acid, and 2,6-naphthalene dicarboxylic acid can be used. Acid, diphenyldicarboxylic acid, diphenylsulfodicarboxylic acid, diphenoxyethanedicarboxylic acid, aromatic sodium dicarboxylic acid such as 5-sodium sulfodicarboxylic acid; oxalic acid, succinic acid, hexane Aliphatic dicarboxylic acids such as diacid, sebacic acid, dimer acid, maleic acid, fumaric acid, etc .; cycloaliphatic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid; p-hydroxybenzoic acid, etc. Hydroxycarboxylic acid and other components. The dicarboxylic acid component may be a dicarboxylic acid ester derivative component, and an esterified product of the dicarboxylic acid compound such as dimethyl terephthalate, diethyl terephthalate, or terephthalic acid 2 may also be used. -Hydroxyethyl methyl ester, dimethyl 2,6-naphthalene dicarboxylate, dimethyl isophthalate, dimethyl adipate, diethyl maleate, dimethyl dimer, etc. Ingredients.

The diol component for obtaining polyester is not particularly limited as long as the effects of the present invention are not impaired. For example, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, and 1,3-butane can be used. Aliphatic dihydroxy compounds such as alcohols, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol; diethylene glycol Polyoxyalkylene glycols such as alcohols, polyethylene glycols, polypropylene glycols, polytetramethylene glycols, etc .; cycloaliphatic dihydroxy compounds such as 1,4-cyclohexanedimethanol, spirodiols, and bisphenol A , Bisphenol S, and other components such as aromatic dihydroxy compounds. Among them, in terms of both flexibility and heat resistance, and operability, ethylene glycol, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, and 1,4- Components of cyclohexanedimethanol and polytetramethylene glycol.

These dicarboxylic acid components and diol components may be used in combination of two or more kinds as long as the effects of the present invention are not impaired.

Examples of the polyolefin that can be preferably used in the present invention include homopolymers of propylene or propylene · α-olefin copolymers that exhibit stereoregularity in the same or opposite rows. Specific examples of the α-olefin include ethylene, 1-butene, 1-pentene, 3-methylpentene-1, 3-methylbutene-1, 1-hexene, 4- Methylpentene-1, 5-ethylhexene-1, 1-octene, 1-decene, 1-dodecene, vinylcyclohexene, styrene, allylbenzene, cyclopentene, drop Ene, 5-methyl-2-nor Olefin and so on. In addition, from the standpoint of making the processing at the time of processing propylene and α-olefin copolymers good, when all the constituent units constituting the polymer are taken as 100 mol%, it is preferable to contain more than 50 mol%. Propylene units. Further, the propylene · α-olefin copolymer may be any of a binary system, a ternary system, and a quaternary system as long as the effects of the present invention are not impaired, and may be a random copolymer or a block copolymer. Either. These propylene homopolymers and propylene · α-olefin copolymers are used within a range that does not impair the object of the present invention, and may be used in combination of plural kinds.

In addition, for the purpose of improving the flexibility of the film, it is also preferable to blend a hydrocarbon-based elastomer into a polyolefin. Examples of the hydrocarbon-based elastomer include a styrene-butadiene copolymer (SBR), a styrene-isobutylene-styrene copolymer (SIS), a styrene-butadiene-styrene copolymer (SBS), and hydrogenation. Styrene-conjugated diene copolymers such as styrene-butadiene copolymer (HSBR) or its hydride, styrene-ethylene-butene-styrene copolymer (SEBS), styrene-isobutylene copolymer And these mixtures. As long as these hydrocarbon-based elastomers do not impair the effects of the present invention, only one kind may be used, or two or more kinds may be used in combination.

The method for setting the glass transition temperature of the layer A to -40 ° C to 40 ° C or the above-mentioned preferred range is not particularly limited as long as the effect of the present invention is not impaired. Examples of the resin that constitutes the A layer include glass transfer. A method in which the temperature is from -40 ° C to 40 ° C or the above-mentioned preferred range. The glass transition temperature of the layer A can be increased by making the resin constituting the layer A higher in the glass transition temperature or by increasing the ratio of the resin having a higher glass transition temperature in the entire resin constituting the layer A.

From the viewpoint of improving the heat resistance and reducing the deformation caused by the weight of the semiconductor wafer, when the 90 ° C dimensional change rate 1 in the Y direction is taken as Ty1 (%), Tx1 and Ty1 are preferably The following formula 1 is satisfied.

Formula 1: 0.10 ≦ | Tx1-Ty1 | ≦ 3.00.

| Tx1-Ty1 | is an index showing the deviation due to the direction of the in-plane 90 ° C dimensional change rate 1. More specifically, the larger | Tx1-Ty1 | means the greater the deviation of the dimensional change rate 1 at 90 ° C in the X direction and the Y direction, and | the smaller | Tx1-Ty1 | means the 90 ° C in the X direction and the Y direction The smaller the deviation of the dimensional change rate 1 is. Since | Tx1-Ty1 | is 0.10 or more and 3.00 or less, the planarity of the film during heating can be made better. That is, since the deformation of the thin film during heating is not excessively uneven, the flatness maintaining effect of the thin film according to the dimensional change can be easily expressed. If | Tx1-Ty1 | is larger than 3.00, since the deformation of the film during heating is excessively non-uniform due to the direction, wrinkles or sagging are likely to be exhibited. Also, the in-plane deformation of | Tx1-Ty1 | is less than about 0.10 regardless of the direction. In the vicinity of the center of the fixed sample, the tension may decrease, which may cause deformation due to the weight of the semiconductor wafer. From the above viewpoint, | Tx1-Ty1 | is more preferably 0.10 to 2.20. As a method for making | Tx1-Ty1 | to be 0.10 or more and 3.00 or less, or the above-mentioned preferable range, for example, a method of biaxially stretching a cast film composed of the aforementioned layer may be mentioned. More specifically, the value of | Tx1-Ty1 | can be reduced by reducing the difference in the stretching magnification in each direction when the biaxial stretching is performed.

The film of the present invention may be a single-layer film or a laminated film of two or more layers as long as the effect is not impaired. In the case of a three-layer structure, from the viewpoint of productivity, it is preferable to make the composition of the two surface layers the same or to make the thickness of the stacked layers of the two surface layers equal.

The film of the present invention preferably has a static friction coefficient of 0.10 or more and 0.80 or less measured from the viewpoints of improvement in operation or elongation accuracy during production and reduction of surface scratches. The so-called static friction coefficient here refers to a coefficient of static friction measured in accordance with JIS K7125 (1999), in which two films are arranged so that opposite sides overlap each other and are rubbed at a speed of 100 mm / minute. By setting the static friction coefficients of different surfaces of the laminated film to each other within the above range, the operation at the time of manufacturing is improved, the elongation accuracy at the time of roll stretching can be improved, and the occurrence of surface scratches can be reduced. In the production process of the film of the present invention, it is required to appropriately control the stretching ratio in a low range as described above. When the static friction coefficient exceeds 0.80, especially when the friction with the roller becomes excessive, the stretching ratio is higher than the design, or scratches may occur on the film surface. When the coefficient of static friction is less than 0.10, the winding deviation of the roll is liable to occur, and productivity is lowered. From the above viewpoints, the static friction coefficient measured on different surfaces of the laminated film is more preferably 0.10 or more and 0.70 or less, and even more preferably 0.10 or more and 0.60 or less.

As a method for setting the static friction coefficient to be 0.10 or more and 0.80 or less, as long as the effect of the present invention is not impaired, the method is not particularly limited, but examples include a case where the film is a single layer, and a case where the film is a laminate. In the constitution, a method of making inorganic particles and / or organic particles having an average particle diameter of 1 μm or more and 10 μm or less included in the outermost layer on at least one side at the time of construction. More specifically, by increasing the content of these particles, the static friction coefficient can be reduced. The average particle diameter referred to herein is a volume average particle diameter. Furthermore, it is also preferable to use a method of blending a hydrocarbon-based elastomer having a different crystallinity into a polyolefin. Due to the blending of resins with different crystallinity, fine unevenness is formed on the surface due to the difference in crystal growth or extensibility during casting, which can make the static friction coefficient a better range.

As the particles, for example, wet and / or dry silica, colloidal silica, aluminum silicate, titanium oxide, calcium carbonate, calcium phosphate, barium sulfate, alumina, mica, kaolin, clay, hydroxyapatite, etc. can be used. The inorganic particles are those obtained by polymerizing styrene, polysiloxane, acrylic acid, methacrylic acid, divinylbenzene, or the like, or organic particles containing polyester, polyamide, or the like as constituents. Among them, it is more suitable to use inorganic particles such as wet and / or dry silica, alumina, etc., and polymerize styrene, polysiloxane, acrylic acid, methacrylic acid, divinylbenzene, or polyester, polyfluorene Organic particles and the like as amines. The particles are preferably two or more of internal particles, inorganic particles, and organic particles, or two or more of internal particles, inorganic particles, and organic particles may be used in combination.

In addition, the content of particles is preferably in a range of 0.01 to 5% by mass, and more preferably 0.03 to 3% by mass with respect to the entire resin composition constituting the outermost layer of the film. When it is less than 0.01% by mass, film winding may become difficult. When it exceeds 5% by mass, there may be a case where glossiness is reduced due to coarse protrusions, and transparency and film forming properties may be deteriorated.

The thin film of the present invention preferably has at least one surface, and the surface roughness SRa (μm) and the ten-point average roughness SRzjis (μm) preferably satisfy the following formula 2.

Formula 2: 5.0 ≦ SRzjis / SRa ≦ 25.0.

By adopting such a state, the uniformity of the uneven shape on the surface of the film can be improved, and the adhesion between the film and the adhesive layer during the adhesion processing can be improved. By setting SRzjis / SRa to 25.0 or less, it is possible to reduce the adhesion obstacle with the adhesive layer due to the large protrusions, or to shorten the curing time during the processing of the adhesive layer and improve productivity. In addition, if SRzjis / SRa is set to less than 5.0, slippage occurs during film formation, which is difficult to achieve in a commonly used manufacturing method, and even if it is achieved, blocking or the like may occur. From the above viewpoints, SRzjis / SRa is more preferably 5.0 or more and 22.0 or less, and even more preferably 5.0 or more and 18.0 or less.

The method for setting SRzjis / SRa to be 5.0 or more and 25.0 or less, as long as the effect of the present invention is not impaired, is not particularly limited, and examples thereof include forming protrusions by blending resins having different crystallinities, and obtaining A method in which the cast film is stretched in at least one direction at a low magnification of 1.04 times or more and 2.00 times or less. Specifically, for example, SRzjis / SRa can be reduced by increasing the stretching ratio in the above-mentioned range by blending a hydrocarbon-based elastomer into the aforementioned polyolefin. By extending at such a low magnification, the size and number of protrusions can be easily controlled to be uniform. In addition, since the degree of alignment of the molecules is also increased due to extension, the strength of the protrusions is increased, and the change in surface shape caused by cutting in the manufacturing process can also be reduced. In addition, as a method for making SRzjis / SRa to be 5.0 or more and 25.0 or less, or a preferable range as described above, a multi-stage method of extending to two or more stages, or a method of simultaneous biaxial extension may be adopted.

The film of the present invention has a thermal shrinkage stress at 90 ° C. in the X and Y directions of preferably 0.010 N / mm ² or more and 5.000 N / mm ² or less. By being in such a state, even in a state where a load is applied to the thin film when a wafer is laminated, elongation or expansion deformation of the thin film during heating can be reduced. By setting the thermal shrinkage stress at 90 ° C to 0.010 N / mm ² or more, it is possible to reduce the decrease in the position accuracy of the wafer caused by dimensional changes during heating or the occurrence of wrinkles caused by in-plane shrinkage deformation. In addition, since the thermal shrinkage stress at 90 ° C. is set to 5.000 N / mm ² or less, it is possible to reduce the peeling or breakage of the wafer caused by the stress caused by the shrinkage of the wafer. Based on the above viewpoint, the heat shrinkage stress at 90 ° C. in the X and Y directions is more preferably 0.030 N / mm ² or more and 4.000 N / mm ² or more, and particularly preferably 0.050 N / mm ² or more and 3.300 N / mm ² or more.

Here, the thermal shrinkage stress at 90 ° C can be measured by the following method. First, a 15 mm (measurement direction) × 4 mm (direction orthogonal to the measurement direction) film was allowed to stand in an environment at a temperature of 25 ° C. and a relative humidity of 65% for 24 hours to obtain a sample. Next, the sample was heated from 25 ° C to 160 ° C at a temperature increase rate of 10 ° C / minute, and the heat shrinkage stress at the time point of 90 ° C was measured, and this was taken as the heat shrinkage stress of 90 ° C. The load at the start of the measurement is 5 g / mm ² . The device used for measuring the thermal shrinkage stress at 90 ° C is not particularly limited as long as it can be used for the above measurement, and may be appropriately selected. For example, TMA / SS6000 (manufactured by SEIKO Instruments Co., Ltd.) can be used.

The method for making the heat shrinkage stress at 90 ° C in the X direction and the Y direction to be 0.010 N / mm ² or more and 5.000 N / mm ² or less, as long as the effect of the present invention is not impaired is not particularly limited, and for example, it may be An example is a cast film having at least one layer of layer A. The glass transition temperature of layer A is set to -30 ° C or higher and 40 ° C or lower, and is extended in at least one direction at a magnification of 1.04 times to 2.00 times. Method, etc.

The shrinkage rate of the film of the present invention after heating at 80 ° C for 1 hour is preferably more than 1.00% and 10.00% or less. By being in such a state, even in a low-temperature heating step, deformation during heating can be reduced. When the shrinkage after heating at 80 ° C. for 1 hour is 1.00% or less, it may be difficult to suppress dimensional change during heating. In addition, when the shrinkage rate after heating at 80 ° C for 1 hour is greater than 10.00%, it shrinks when heated in an adhesive processing step or the like, and the dimensional change may increase when heated in subsequent semiconductor processes. The shrinkage after heating at 80 ° C for 1 hour is preferably 2.00% or more and 8.00% or less, and particularly preferably 3.00% or more and 6.00% or less. The method for making the shrinkage rate after heating at 80 ° C for more than 1.00% to 10.00% or less in the above-mentioned preferred range is not particularly limited as long as the effect of the present invention is not impaired. For example, a cast film may be used. 1.40 times or more and 2.00 times or less, a method of extending in at least one direction, etc.

The film T of the present invention preferably satisfies the following formula 3 when the stress Tb is at 5% stretching at 25 ° C after heating at 90 ° C for 10 minutes.

Formula 3: 0.85 ≦ Tb / Ta ≦ 1.30.

Tb / Ta satisfying Equation 3 means that the change in elongation characteristics after heating is small. By being in such a state, the film can also be preferably used in the case where the film is expanded after the heating step. From the above viewpoints, Tb / Ta is more preferably 0.85 to 1.23, and particularly preferably 0.85 to 1.15. The method for setting Tb / Ta to be 0.85 or more and 1.30 or less or the above-mentioned preferred range is not particularly limited as long as the effect of the present invention is not impaired. For example, for a cast film, a temperature of 70 ° C or higher and a film melting point or lower A method for performing heat treatment. The heat treatment can be performed by a conventional method such as a roll annealing or a tenter method. In addition, as long as the effect of the present invention is not impaired, stretching can be performed simultaneously with heating.

The film of the present invention preferably has a maximum stress Ka at 50 ° C and 50% elongation and a stress Kb at 50% elongation that preferably satisfy the following formula 4.

Formula 4: 0.70 ≦ Kb / Ka ≦ 1.00.

Kb / Ka satisfying Equation 4 means that when the film is stretched at room temperature, the drop point stress is small or does not substantially occur. When the stress at the falling point is high, the thickness unevenness or the stress unevenness at the central portion and the end portion during expansion is likely to affect the degree of elongation, and the uniformity of elongation in the surface may be reduced. Therefore, the uniformity of the in-plane elongation can be further improved by adopting such an aspect. From the above viewpoint, Kb / Ka is more preferably 0.80 or more and 1.00 or less, and even more preferably 0.90 or more and 1.00 or less. The method of making Kb / Ka into a preferable range is not particularly limited as long as the effect of the present invention is not impaired. For example, a method of biaxially stretching a cast film at an area magnification of 1.04 times or more and 2.00 times or less can be mentioned. .

From the viewpoint of reducing the decrease in the yield during wafer dicing, the film of the present invention is preferably 10 pieces / m ² or less of adhered foreign matter having a diameter of 100 μm or more, and more preferably 2 pieces / m ² or less. Here, the diameter of the foreign object refers to the distance between two points on the outline of the foreign object, and the value becomes the largest. Since the number of adhered foreign matter having a diameter of 100 μm or more is 10 pieces / m ² or less, occurrence of chipping during wafer dicing can be suppressed, and the decrease in yield can be reduced. The method for making the attached foreign matter having a diameter of 100 μm or more to 10 pieces / m ² or less, or the above-mentioned preferred range is not particularly limited as long as the effect of the present invention is not impaired, and a method for improving the cleanliness of the film forming room may be mentioned. In the film-making production line, there are a method of removing an adherent foreign body by setting an adhesive roller or a dust collector, a method of using an oven, and extending in a hot air environment. In addition, the smaller the number of attached foreign matter having a diameter of 100 μm or more, the better, and the lower limit thereof is preferably 0 / m ² .

The number of attached foreign matter having a diameter of 100 μm or more can be measured by the following procedure. First, use a reflected light from a 3-wavelength fluorescent lamp in a dark room to perform a visual inspection to extract foreign objects from the film sample. When a foreign object was observed, the foreign object was observed under magnification with an electron microscope, the length of the major axis was measured, and the one having a major axis length of 100 μm was again extracted. Then, the number of the extracted foreign matter was divided by the area of the thin film sample, and the number of attached foreign matter (diameter / m ² ) having a diameter of 100 μm or more was obtained.

The thin film of the present invention preferably has a thickness unevenness of 10.0% or less from the viewpoint of reducing the decrease in yield during wafer dicing. Since the thicknesses are all less than 10.0%, the frequency of chipping caused by sloshing during wafer dicing is reduced, the decrease in yield is reduced, and the uniformity during expansion is improved. From the above viewpoint, the thickness unevenness is preferably 8.0% or less. The method of reducing the thickness unevenness to 10.0% or less is not particularly limited as long as the effect of the present invention is not impaired. For example, a method of stretching at a stretch ratio of 1.04 times or more and 2.00 times or less can be mentioned. By stretching under such conditions, it is possible to reduce thickness unevenness while suppressing a decrease in flexibility. When the stretching ratio is less than 1.04, it is difficult to eliminate thickness unevenness of the cast film, and if the stretching ratio is 2.00 times or more, the thickness unevenness may increase. The smaller the thickness unevenness, the better, and the lower limit is preferably 0.0%. As the stretching conditions, it is also preferable to use a method of reducing the stretching tension by setting the stretching temperature to 90 ° C or higher and below the melting point of the film.

Next, a method for producing a thin film of the present invention will be described. The method for producing a film of the present invention is characterized by having a step of extending in at least one direction at a magnification of 1.04 times to 2.00 times. By being in such a state, dimensional stability during heating is increased. Based on the above viewpoint, it is preferable to have a step extending in at least one direction at a magnification of 1.20 times to 1.80 times, and more preferably a step extending in at least one direction at a magnification of 1.40 times to 1.70 times. Moreover, in the manufacturing method of the film of this invention, as long as the effect of this invention is not impaired, the film may be biaxially stretched.

Hereinafter, the method for producing the film of the present invention will be specifically described using a single-layer film made of polyester as an example, but the present invention is not limited to this example in terms of explanation.

First, polyester is supplied to a biaxial extruder and melt-extruded. At this time, it is preferable to set the oxygen concentration to 0.7% by volume or less under an environment where nitrogen flows in the extruder, and the extrusion temperature is controlled to be within a range of 20 to 30 ° C higher than the melting point of the polyester. Next, a filter or a gear pump is used to remove foreign matter and equalize the extrusion amount, respectively, and spit it out from the T-shaped die on the cooling drum. At that time, by using an electrostatic application method in which a high-voltage electrode was used to statically close a cooling roller and a resin, a casting method in which a water film was placed between a casting roller and an extruded polymer sheet was used to set the temperature of the casting roller. Polyester has a glass transition point of -20 ° C or higher and a glass transition temperature or lower, and the method of adhering the extruded polymer, or a combination of these methods, makes the sheet-like polymer adhere to the casting drum and cool and solidify A cast film was obtained. Among these casting methods, an electrostatic application method is preferably used from the viewpoint of productivity or planarity.

In the method for producing a film of the present invention, the film is stretched in at least one axial direction at a magnification of 1.04 times or more and 2.00 times or less in order to impart dimensional stability during heating. The stretching magnification when extending in the uniaxial direction is preferably 1.20 times or more and 1.80 times or less, and more preferably 1.40 times or more and 1.70 times or less. When the film is stretched in the biaxial direction, the area magnification is preferably in the above range. The elongation speed should be 100% / minute or more and 200,000% / minute or less. The stretching system can be performed at any temperature above room temperature, but it is preferably 20 ° C or higher and 160 ° C or lower, and more preferably preheated for 1 second or longer before stretching. In addition, the stretching system can be a biaxial stretching method in which the cast film is stretched in the longitudinal direction and then stretched in the width direction, or stretched in the width direction and then stretched in the length direction, or the length of the film is stretched. The simultaneous biaxial stretching method, which extends substantially simultaneously in the direction and the width direction, and the uniaxial stretching method, which extends only in the longitudinal direction or the width direction, are performed. Here, the so-called length direction refers to the direction of travel of the film, and the so-called width direction refers to a direction parallel to the film surface and orthogonal to the length direction. In addition, as long as the effect of the present invention is not impaired, the stretching may be performed in one stage or in multiple stages.

Furthermore, the film may be heat-treated after stretching. The heat treatment can be carried out in an oven, on a heated roll, or the like by any conventional method. This heat treatment is preferably performed at a temperature equal to or higher than the elongation temperature and an elongation temperature + 50 ° C or lower. The temperature of the heat treatment mentioned here means the temperature which becomes the highest temperature among the heat treatment temperatures performed after stretching. In addition, the heat treatment time may be any one within a range that does not deteriorate the characteristics.

After the heat-set film is cooled, it is rolled up into an intermediate product roll. In addition, the film was unwound from the intermediate product roll, cut in parallel with the longitudinal direction so as to have a desired width, and wound up to obtain a final product roll. In addition, the final product roll obtained from one intermediate product roll may be one or plural.

The film of the present invention controls the elongation characteristics at room temperature and the dimensional change characteristics at elevated temperatures. Therefore, the film of the present invention has both flexibility and heat resistance, and can be suitably used as a substrate for a semiconductor process.

    [Example]    

Hereinafter, the present invention will be described in detail through examples. The characteristics are measured and evaluated by the following methods.

    (1) Stress Ta at 5% elongation at 25 ° C    

According to JIS K7127 (1999, test piece type 2), measurement was performed at 25 ° C. and 65% RH using a film strength elongation measuring device (AMF / RTA-100) manufactured by ORIENTEC Corporation. First, a sample having a length of 150 mm and a width of 10 mm was cut out in an arbitrary direction, and stretched at an original length of 50 mm and a stretching speed of 300 mm / min to obtain a stress Ta (unit: MPa) at 5% stretch. The same measurement was performed five times for one sample, and the average value was calculated. In addition, the direction was changed clockwise every 5 °, and similarly measured, the maximum value of the values in each direction from 0 ° to 175 ° was taken as the stress Ta (MPa) at 5% elongation at 25 ° C.

    (2) 90 ° C dimensional change rate 1 (Tx1, Ty1)    

First, a thin film sample of 15 mm (measurement direction) x 4 mm (direction orthogonal to the measurement direction) is cut at room temperature, and it is left to stand for 24 hours under the environment of a temperature of 25 ° C and a relative humidity of 65%. The length in the measurement direction (L ₀ ). Next, this film sample was heated from 25 ° C to 160 ° C under a load of 120 g / mm ² at a temperature increase rate of 10 ° C / min, and the length (L ₁ ) in the measurement direction at 90 ° C was measured. From the obtained values of L ₀ and L ₁ , the 90 ° C dimensional change rate 1 of the thin film sample was determined by the following Equation 5.

Formula 5: Size change rate 90 ℃ 1 (%) = ( L 1 -L 0) × 100 / L 0.

The measurement direction was selected arbitrarily. The selected measurement direction was measured five times, and the average value of the obtained measurement values was taken as the 90 ° C dimensional change rate 1 (%) in that direction. Further, the measurement direction was rotated 5 ° to the right, and the same measurement was performed, and the value of the dimensional change rate 1 (%) at 90 ° C in each direction until the rotation angle reached 175 ° was similarly obtained. The direction in which Tx1 (%) and Tx1 (%) of the maximum value obtained are defined as the X direction. In addition, the direction orthogonal to the X direction in the plane is defined as the Y direction, and the dimensional change rate Ty1 (%) in the Y direction is determined from the value obtained by the previous measurement.

    (3) 90 ° C dimensional change rate 2 (Tx2)    

The measurement was carried out in the same manner as in the method described in (2), except that the load during measurement was set to 5 g / mm ² and the measurement direction was set to the X direction. The obtained value was taken as Tx2 (%). The X direction referred to here is the same as the X direction defined in (2).

    (4) Surface alignment coefficient    

Using an Abbe refractometer 4T made by ATAGO Co., Ltd. equipped with a polarizer, the refractive index in each direction of the film was measured, and the surface alignment coefficient was determined by the following formula. The light source is a halogen lamp, the upper one is a refractive index of 1.740, and the immersion liquid is a diiodomethane (refractive index of 1.740). In addition, the measurement was performed using a sample that was temperature-controlled and humidity-controlled for 24 hours in an environment of 23 ° C. and 65 RH%, and performed on both sides of the film in this environment. The measurement system first regards any direction parallel to the film surface as α, the direction orthogonal to the film surface as β, the direction orthogonal to α and β (thickness direction) as γ, and Abbe's refraction The rate meter measures the refractive index (nα, nβ, nγ) in each direction. Using the obtained values, the surface alignment coefficients (fn ₀ ) when the two directions on the film surface are α and β are obtained by the following Equation 6.

Formula 6: fn ₀ = (nα + nβ) / 2-nγ.

Next, γ is fixed. While maintaining the parallelism of α and β to the film surface, they are rotated right every 5 ° to become nα5 and nβ5. The refractive index (nα5, nβ5) in each direction is measured with an Abbe refractometer. , Nγ), where nα in Equation 6 is replaced by nα5, and nβ is replaced by nβ5, and the surface alignment coefficients (fn ₅ ) when the two directions on the film surface are α5 and β5 are obtained. Hereinafter, the same measurement is repeated in the same manner until the two directions on the film surface become α85 and β85. The average value of the measured values of the obtained 18 batches of fn ₀ to fn ₈₅ was taken as the surface alignment coefficient (fn).

    (5) Glass transition temperature of each layer    

Using differential thermal analysis (DSC), in accordance with JIS K7121 (2012), in a nitrogen environment, after holding at -120 ° C for 5 minutes, the measurement sample was heated at a rate of 20 ° C / min to 250 ° C, and the measurement results were obtained from the measurement results. It is calculated by the following Equation 7.

Equation 7: Glass transition temperature = (extended glass transition start temperature + extrapolated glass transition end temperature) / 2

Device: Robot DSC-RDC220 made by SEIKO Electronics Industry Co., Ltd.

Data analysis system: Discsession SSC / 5200

Sample weight: 5mg

When the film has a laminated structure, firstly use a transmission electron microscope H-7100FA (manufactured by Hitachi, Ltd.) for the thickness direction section of the film cut with a microtome, and enlarge it at an acceleration voltage of 75 kV. Up to 40,000 times, an image is taken, and the layer structure is identified and the thickness of each layer is measured. Also, depending on the situation, in order to improve the contrast of the layers, a well-known dyeing method such as RuO ₄ or OsO ₄ is used. From the value of the thickness of each layer obtained, a sample corresponding to the depth portion of each layer was collected, and the glass transition temperature of each layer was measured according to the method described above.

In addition, when the measurement result is a multiple glass transition temperature, the value obtained by the following method is taken as the glass transition temperature of this layer. First, the glass transition temperature of the film was measured by the method described above, and the obtained measured values were set to Tg1, Tg2‧‧‧Tgn in order of decreasing temperature. Next, in accordance with JIS K7244 (1999), a dynamic viscoelasticity measuring device "DMS6100" manufactured by SEIKO Instrument Co., Ltd. was used to obtain the tan δ per temperature of the film, and the temperature at which the maximum value was given corresponded to Tg1, Tg2‧‧‧ in order of decreasing. Tgn. Among Tg1, Tg2‧‧‧Tgn, when the value corresponding to each layer is separated, the temperature at which the value of tanδ is the maximum is used as the glass transition temperature of the layer. The measurement conditions for the dynamic viscoelasticity measurement are in the tensile mode, the driving frequency is 1 Hz, the distance between the chucks is 5 mm, and the temperature rise rate is 2 ° C / min.

    (6) Specification of layer structure    

From the glass transition temperature of each layer of the film measured in (5), the layer A and the other layers (referred to as layer B) are specified.

    (7) Static friction coefficient    

Using a Toray sliding tester 200G-15C (manufactured by MAKINO SEISAKUSHO), in accordance with JIS K7125 (1999), two films were arranged so that one side was in contact with the opposite side, and the value at the time of rubbing was measured three times. Take the average value as the coefficient of static friction.

    (8) Surface roughness SRa, ten-point average roughness SRzjis    

Using a stylus method, a high-definition fine shape measuring device (three-dimensional surface roughness meter), in accordance with JIS B0601 (2001), the three-dimensional surface roughness of the sample surface was measured under the following conditions. Then, the surface roughness SRa and ten-point average roughness SRzjis were calculated using the analysis system (type TDA-31) built in the measuring instrument.

Measuring device: 3-dimensional fine shape measuring device (type ET-4000A) manufactured by Kosaka Research Institute

Analysis equipment: 3-dimensional surface roughness analysis system (type TDA-31)

Stylus: 0.5μmR radius, 2μm diameter, diamond

Acupressure: 100μN

Measurement direction: once in the film length direction and film width direction (calculate the average of both after measurement)

X measurement length: 1.0mm

X travel speed: 0.1mm / s (measurement speed)

Y travel distance: 5μm (measurement interval)

Y lines: 81 (measured)

Z magnification: 20 times (vertical magnification)

Low domain cut-off: 0.20mm (cutoff value)

High-end cutoff: R + Wmm (roughness cutoff value), R + W means not cut-off.

Filtering method: Gaussian space type

Leveling: Yes (Tilt Correction)

Reference area: 1mm ² .

    (9) Thermal shrinkage stress at 90 ° C    

A film of 15 mm (measurement direction) x 4 mm (direction orthogonal to the measurement direction) after standing for 24 hours at a temperature of 25 ° C and a relative humidity of 65% was assembled using TMA / SS6000 (manufactured by SEIKO Instruments Co., Ltd.) in L In the control mode, the temperature was increased from 25 ° C. to 10 ° C./min to 160 ° C. at a temperature increase rate of 10 ° C./min, and the heat shrinkage stress at 90 ° C. was determined. The load at the start of the measurement was 5 g / mm ² . The measurement directions are the X direction and the Y direction defined by (2).

    (10) Shrinkage after heating at 80 ° C for 1 hour    

The film was heated at 80 ° C. for 1 hour, and calculated from the dimension before heating and the dimension after heating by the following formula 8. In addition, each dimension is measured by the method prescribed | regulated by JIS K7133 (1999).

Formula 8: Shrinkage (%) = (size before heating-size after heating) / size before heating × 100.

    (11) Stress Tb at 5% extension at 25 ° C after heating at 90 ° C for 10 minutes    

A stress at 5% elongation at 25 ° C was measured in the same manner as in (1), except that a measurement sample that was left standing in an oven set at 90 ° C for 10 minutes was used, and the obtained value was taken as Tb.

    (12) The ratio of the maximum stress Ka after 50% elongation at 25 ° C to the stress Kb at 50% elongation    

A tensile test of the film was performed by the method described in (1), and the stress at 50% elongation was obtained. Then, from the maximum value of the stress value in the area where the elongation of the stress-strain curve obtained by the measurement is 50% or less, the maximum stress after 50% elongation is read. The same measurement was performed five times using samples in the same measurement direction. The average stress was calculated for the stress at 50% elongation and the maximum stress after 50% elongation, and the obtained value was regarded as 50% elongation in the measurement direction. The maximum stress Ka and the stress Kb at 50% elongation are calculated as the ratio of Ka to Kb in that direction (Kb / Ka). Furthermore, the measurement direction was changed clockwise every 5 °, and the same measurement was repeated to calculate the ratio of Ka to Kb in each direction from 0 ° (the initial measurement direction) to 175 °, and the average value in all directions was used. .

    (13) Number of adhered foreign matter with a diameter of 100 μm or more    

A film of 1m (width direction) × 10m (length direction) was cut out at the central part of the roll sample in the width direction as a sample, and the reflected light of a 3-wavelength fluorescent lamp was used in a dark room for visual inspection. When a foreign substance is observed, the foreign substance is observed with an electron microscope (LEICA DMLM Leica Microsystems Co., Ltd.) at a magnification of 100 times, and the length of the major axis of the foreign substance is measured by the measuring function of the microscope. The number of those having a long diameter of 100 μm or more in the foreign body is regarded as C, and the number of attached foreign materials (pieces / m ² ) having a diameter of 100 μm or more is converted by using Equation 9 below. When the size of the film does not satisfy the above-mentioned size, the entire film is used as a sample and a visual inspection is performed.

Formula 9: The number of adhered foreign matter (100 / m in diameter) (piece / m ² ) = C (piece) / 10 (m ² ).

    (14) Uneven thickness    

From the positions of the central portion and the both end portions in the width direction of the roll sample, 10 pieces of film were cut out at 10 cm × 10 cm and used as samples for evaluation. For each sample, a thickness of 5 points in the longitudinal direction and 5 points in the width direction was measured, and a total thickness of 10 points was measured. From the average value, the maximum value, and the minimum value, the thickness unevenness was determined according to the following Equation 10.

Equation 10: Uneven thickness (%) = (maximum thickness-minimum thickness) / average thickness

The average value of the thickness unevenness of each of the 10 samples obtained at each of three points (both end portions and central portion) in the width direction was calculated and used as the thickness unevenness. When the film is a sheet sample, 30 pieces of 10 cm × 10 cm are cut out at any position on the sheet, and the average value of the thickness unevenness of each sample is calculated and adopted as the thickness unevenness.

    (15) Uniform extensibility    

On a 300mm × 300mm square film cut out randomly, draw 9 straight lines at 30mm intervals parallel to the sides of one group, and draw 9 straight lines at 30mm intervals parallel to the sides of the other group. A straight line is used as the measurement sample. Using a simultaneous biaxial extension device, the obtained measurement sample was extended in a direction parallel to one side of the group and a direction parallel to the side of the other group under the following conditions. From the interval of the straight line, the following criteria were used: Evaluation. In addition, the interval of a straight line is obtained by removing two straight lines at both ends in each direction, and then measuring 6 intervals formed by 7 straight lines (a total of 12 intervals in 2 directions), and using the value that is farthest from 39 mm as the measurement value . Uniform elongation is considered acceptable for B or higher.

    <Extended conditions>    

Extension device: KARO IV experimental tensioner made by BRUCKNER

Extension temperature: 25 ℃

Extension speed: 10mm / min

Extension magnification: 1.30 times.

    <Evaluation Criteria>    

S: The linear interval in the stretched film is 39 ± 1 mm.

A: Does not meet S, and the linear interval in the stretched film is 39 ± 3mm.

B: Does not meet S and A. The linear interval in the stretched film is 39 ± 6mm.

C: Does not meet any of S and A and B.

    (16) Uniform extensibility after heating    

A 300 mm × 300 mm square film cut out at random was heat-treated at 90 ° C. for 10 minutes, and then evaluated in the same manner as described in (15).

    (17) Dimensional stability (heat resistance) at 90 ° C    

A 200 mm × 200 mm square film cut out arbitrarily was attached to a stainless steel metal frame (outside: 200 mm × 200 mm, inside: 180 mm × 180 mm) with a double-sided adhesive tape No.500AB made by Nitto Denko Corporation and measured as a measurement. sample. Next, the measurement sample was left standing on a hot plate heated to 90 ° C. so that the film attached to the metal frame contacted the heating surface, and the amount of arching relative to the reference plane after standing for 240 minutes was measured. From the obtained results, dimensional stability was evaluated on the following basis. In the measurement of the amount of bulging, the reference plane was set as the heating surface of the hot plate. The measurement is performed by changing the thickness of the metal frame used to 1mm, 2mm, and 3mm. When the sample is viewed from a horizontal position, the thickness of the metal frame cannot be seen with a deformed film, and even a metal frame with a thickness of 3mm can be used. The case where the film was seen was regarded as C evaluation. For dimensional stability, B or higher is considered acceptable.

S: The dome of the film is 1 mm or less.

A: Does not meet S, and the dome of the film is 2 mm or less.

B: Does not meet S and A, and the dome of the film is 3 mm or less.

C: Does not meet any of S and A and B.

    (18) Dimensional stability (heat resistance) at 120 ° C    

The heat resistance was evaluated in the same manner as in the method described in (17), except that the temperature of the hot plate was 120 ° C.

    (19) Quality    

From the center position in the width direction and the positions in both ends of the width direction of the sample collected in (13), 10 pieces of 200 mm × 200 mm film samples were cut out, and 30 pieces were cut out in total. All the samples were observed with an optical microscope at a magnification of 100 times and a field of view of 10, and the presence or absence of scars having a length of 1 m or more was confirmed. The rounded value of the first decimal place of the average of the number of visual fields where a flaw having a length of 1 μm or more was observed in each sample was taken as the number of visual fields where a flaw having a length of 1 μm or more was observed. Based on the number of attached foreign matter having a diameter of 100 μm or more measured in (13) and the number of visual fields where a flaw of 1 μm or more in length was observed, the following criteria were used to evaluate the quality. In addition, when the number of visual fields in which a length of 1 μm or more is observed and the number of attached foreign matter having a diameter of 100 μm or more are different from each other (for example, when the former is A and the latter is B), the poorer evaluation is used ( B).

S: The number of visual fields where a flaw having a length of 1 μm or more is observed is 0, and the number of attached foreign matter having a diameter of 100 μm or more exceeds 0 and is 5 or less.

A: The number of visual fields where a flaw having a length of 1 μm or more was observed was one. Or, the number of attached foreign matter having a diameter of 100 μm or more exceeds 5 and is 8 or less.

B: The number of visual fields where a flaw having a length of 1 μm or more was observed was 2 to 3. Or, the number of attached foreign matter having a diameter of 100 μm or more exceeds 8 and is 10 or less.

C: The number of visual fields where a flaw having a length of 1 μm or more was observed was 4 or more. In addition, the number of attached foreign matter having a diameter of 100 μm or more is more than ten.

    (20) Adhesiveness    

An adhesive layer composition solution (adhesive: 100 parts by mass of Japan Carbide Industrial Co., Ltd.) acrylic acid was applied on the surface of a square film of 200 mm × 200 mm cut out arbitrarily by a wire rod coating method so that the thickness became about 10 μm. Ester resin-based solvent-based pressure-sensitive adhesive "Nissetsu" (registered trademark) "KP-2369" / 2 parts by mass of cross-linking agent "CK-131"), and then high-temp hot air oven made by ESPEC -OVEN PHH-200, dried at 100 ° C for 1 minute, and left to stand for 3 days in an environment of room temperature 25 ° C and relative humidity 65%. The sample thus obtained was cut into a size of 150 mm × 30 mm, and was stretched by 50% at a speed of 300 mm / minute at a room temperature of 25 ° C. using a film tensile strength measuring device (AMF / RTA-100) made by ORIENTEC Corporation. Then, an acrylic adhesive tape (Nitto 31B (manufactured by Nitto Denko Corporation)) was bonded to the adhesive surface with a rubber roller, and crimped with a 5 kg crimping roller. After standing for 24 hours, a 10 mm width was cut out. As an evaluation sample, the end portion of the acrylic pressure-sensitive adhesive tape of this evaluation sample was turned back to 180 °, and the peel strength was measured with a tensile tester, and evaluated using the following criteria.

S: Peel strength is 10N / 25mm or more.

A: The peel strength is 8N / 25mm or more and less than 10N / 25mm.

B: Peel strength is 6N / 25mm or more and less than 8N / 25mm.

C: Peel strength is less than 6N / 25mm.

    (Resin)    

The resin used in the production of the film is as follows.

    (Polyester A)    

Starting from terephthalic acid and ethylene glycol, antimony trioxide was used as a catalyst, and polymerization was performed by a common method to obtain a polyester A having an inherent viscosity of 0.65.

    (Polyester B)    

The polyester A contains a polyethylene terephthalate particle masterbatch having an intrinsic viscosity of 0.65 and an intrinsic viscosity of aggregated silica particles having a volume average particle size of 4.5 μm having a particle concentration of 10% by mass.

    (Polyester C)    

PBT-polyether copolymer "Hytrel" (registered trademark) 5557 manufactured by Toray-DuPont

    (Polyester D)    

Polybutylene terephthalate with inherent viscosity of 0.8

    (Polyester E)    

PBT-polyether copolymer "Hytrel" (registered trademark) 3001 manufactured by Toray-DuPont

    (Polyolefin A)    

Crystalline polypropylene made from Prime Polymer (stock), TF850H

    (Polyolefin B)    

Ethylene-octene-1 copolymer "Engage" (registered trademark) EG8200 made by DuPont Dow

    (Polyolefin C)    

Hydrogenated styrene butadiene copolymer (HSBR) "SRNARON" (registered trademark) 1320P manufactured by JSR Corporation.

    (Example 1)    

The raw materials for layer A adjusted to the composition shown in Table 1 were supplied to a biaxial extruder having an oxygen concentration of 0.2% by volume, and the barrel temperature of the biaxial extruder was set to 270 ° C. so as to reach the layer A. After the raw materials used are melted, they are sent to a T-shaped die through a short tube and a nozzle set at a temperature of 270 ° C, and a thin sheet is discharged from the T-shaped die on a cooling roller whose temperature is controlled at 25 ° C. At that time, a linear electrode with a diameter of 0.1 mm was used and static electricity was applied to make it adhere to a cooling drum to obtain a cast film. Next, a simultaneous biaxial stretching device was used to stretch at a preheating temperature of 80 ° C and an extension temperature of 90 ° C in the length and width directions at a rate of 1.44 times. Then, the dust on both surfaces of the film was removed with a dust collector to obtain a total thickness of 180 μm single-layer film. Table 1 shows the evaluation results of each characteristic.

    (Examples 2 to 14, 18 to 28, 34, 36 to 38, 40)    

A single-layer film having a total thickness of 180 μm was obtained in the same manner as in Example 1 except that the film configuration, extrusion temperature, and stretching conditions were as shown in Tables 1 to 6. Tables 1 to 6 show the evaluation results of each characteristic. In addition, since the layer A does not exist in Examples 18 and 19, the "raw material for obtaining the A layer" in Example 1 becomes the "raw material for obtaining the B layer".

    (Example 15)    

A cast film was obtained in the same manner as in Example 8. Next, using a simultaneous biaxial stretching device, at a preheating temperature of 100 ° C and an extension temperature of 120 ° C, the film was stretched at a ratio of 1.44 times in the length and width directions, and then heat-treated in a zone heated to 130 ° C for 10 seconds. Before winding, the dust on the surface of the film was removed by using a dust collector to obtain a single-layer film with a total thickness of 180 μm. Table 3 shows the evaluation results of each characteristic.

    (Example 16)    

The film configuration is shown in Table 3. The raw materials for obtaining the A1 layer and the raw materials for obtaining the A2 layer shown in Table 3 were each supplied to each biaxial extruder having an oxygen concentration of 0.2% by volume. The barrel temperature of each extruder is set to 270 ° C, and the raw materials are melted and merged. After passing through the short tube and nozzle set at 270 ° C, they are sent to the T-shaped die, and the T-shaped die is cooled at a temperature controlled at 25 ° C Thin flakes are ejected from the drum. Then, in the same manner as in Example 1, a laminated film having a total thickness of 180 μm was obtained. Table 3 shows the evaluation results of each characteristic.

    (Example 17)    

The film configuration is shown in Table 3. The raw materials for obtaining the layer A and the raw materials for obtaining the layer B shown in Table 3 were each supplied to each biaxial extruder having an oxygen concentration of 0.2% by volume. Both the barrel temperature of the extruder supplied with the raw material for layer A and the barrel temperature of the extruder supplied with the raw material for layer B were set to 260 ° C, and the raw materials were melted and merged, and the passing temperature was set at 260. The short tube and nozzle at ℃ are sent to the T-shaped die, and the sheet is ejected from the T-shaped die on a cooling roller whose temperature is controlled at 25 ° C. Then, a laminated film having a total thickness of 180 μm was obtained in the same manner as in Example 1 except that the elongation temperature was set as shown in Table 3. Table 3 shows the evaluation results of each characteristic.

    (Examples 29 to 33)    

A cast film was obtained in the same manner as in Example 1. Next, use a roll stretcher to stretch at a preheating temperature of 80 ° C and a stretching temperature of 90 ° C in the longitudinal direction at the magnifications shown in Table 5. Then use a tenter stretcher at a preheating temperature of 80 ° C and a stretching temperature of 90 ° C. The width direction was extended at the magnification described in Table 5, and then the dust on both surfaces of the film was removed with a dust collector to obtain a single-layer film with a total thickness of 180 μm. Table 5 shows the evaluation results of each characteristic.

    (Example 35)    

A cast film was obtained in the same manner as in Example 1. Next, use a roll stretcher to stretch at a preheating temperature of 80 ° C and a stretching temperature of 90 ° C in the longitudinal direction at the magnifications shown in Table 5. Then use a tenter stretcher at a preheating temperature of 80 ° C and a stretching temperature of 90 ° C. The width direction was extended at the magnification shown in Table 5, and a single-layer film having a total thickness of 180 μm was obtained. Table 5 shows the evaluation results of each characteristic.

    (Example 39)    

A cast film was obtained in the same manner as in Example 1 except that the raw material composition for obtaining the layer A was shown in Table 6. Next, using a simultaneous biaxial stretching machine, at a preheating temperature of 100 ° C and an extension temperature of 120 ° C, after stretching at 1.44 times in the length and width directions, hold for 3 seconds, and then use a dust collector to remove dust on both surfaces of the film to obtain Single-layer film with a total thickness of 180 μm. Table 6 shows the evaluation results of each characteristic.

    (Comparative Examples 1 to 5)    

A single-layer film having a total thickness of 180 μm was obtained in the same manner as in Example 1 except that the film configuration, extrusion temperature, and extension conditions were as shown in Table 7. Table 7 shows the evaluation results of each characteristic. It should be noted that the extension mode "-" of Comparative Examples 2 and 5 means that the extension itself is not performed.

The resin composition in the film structure is calculated by taking the entire resin component constituting each layer as 100% by mass. The so-called D surface is the surface that contacts the casting drum during film formation, and the so-called ND surface is the surface opposite to the D surface. The same applies to Tables 2 to 7.

Example 16 is a three-layer thin film having two types of layers equivalent to the layer A, and each layer is described as the layer A1 and the layer A2.

    [Industrial availability]    

According to the present invention, a thin film having both flexibility and heat resistance and a method for manufacturing the same can be provided. The thin film of the present invention can be suitably used as a substrate for a semiconductor process.

Claims (16)

A film characterized by a stress Ta of 1.0 MPa or more and 20.0 MPa or less at 5% extension at 25 ° C, a load of 120 g / mm ² is applied, and the temperature is raised from 25 ° C to 160 ° C at a rate of 10 ° C / min. The dimensional change rate at 90 ° C is taken as the 90 ° C dimensional change rate 1, the direction in which the 90 ° C dimensional change rate is the largest is taken as the X direction, and the direction orthogonal to the X direction in the film plane is taken as the Y direction. When the 90 ° C dimensional change rate in the X direction is taken as Tx1 (%), Tx1 is -10.00% or more and 10.00% or less. For example, if the film of claim 1 is applied with a load of 5 g / mm ² , the dimensional change rate at 90 ° C. when the temperature is raised from 25 ° C. to 160 ° C. at a temperature increase rate of 10 ° C./min is regarded as the 90 ° dimensional change rate 2, When the 90 ° C dimensional change rate 2 in the X direction is taken as Tx2 (%), Tx2 is -10.00% or more and 1.00% or less.     For example, the film of claim 1 or 2 has a surface alignment coefficient of at least one side of 0.0080 to 0.0800.         The thin film according to any one of claims 1 to 3, wherein when the layer having a glass transition temperature of -40 ° C or higher and 40 ° C or lower is used as the A layer, it has one or more A layers.         For example, if the film of any one of claims 1 to 4 uses the 90 ° C dimensional change rate 1 in the Y direction as Ty1 (%), the Tx1 and Ty1 satisfy the following formula 1; -Ty1 | ≦ 3.00.         The film according to any one of claims 1 to 5, wherein the static friction coefficients of different surfaces of the laminated film measured from each other are 0.10 or more and 0.80 or less.         For example, the film of any one of claims 1 to 6, which is on at least one side, has a surface roughness SRa (μm) and a ten-point average roughness SRzjis (μm) satisfying the following formula 2; formula 2: 5.0 ≦ SRzjis /SRa≦25.0.     The film according to any one of claims 1 to 7, wherein the heat shrinkage stress at 90 ° C in the X direction and the Y direction is 0.010 N / mm ² or more and 5.000 N / mm ² or less.     The film according to any one of claims 1 to 8, which has a shrinkage of more than 1.00% and 10.00% or less after heating at 80 ° C for 1 hour.         The film according to any one of claims 1 to 9, wherein the Ta and the stress Tb at 5% stretching at 25 ° C after heating at 90 ° C for 10 minutes satisfy the following formula 3; formula 3: 0.85 ≦ Tb / Ta ≦ 1.30.         For example, the film of any one of claims 1 to 10, the maximum stress Ka at 50% elongation at 25 ° C and the stress Kb at 50% elongation satisfy the following formula 4; formula 4: 0.70 ≦ Kb / Ka ≦ 1.00.         As for the film of any one of claims 1 to 11, the 90 ° C dimensional change rate 1 in all directions is -25.00% or more and 10.00% or less.         For example, the film of any one of claims 1 to 12 has a 90 ° C dimensional change rate 2 in all directions of -25.00% or more and 1.00% or less.     For the film according to any one of claims 1 to 13, the number of attached foreign matter having a diameter of 100 μm or more is 10 pieces / m ² or less.     If the film of any one of claims 1 to 14, its thickness is not all 10.0% or less.         A method for manufacturing a thin film, which is the method for manufacturing a thin film according to any one of claims 1 to 15, characterized in that it has a step of extending in at least one direction at a magnification of 1.04 times to 2.00 times.