JPWO2018198864A1 - Film and method for producing film - Google Patents

Abstract

5% elongation stress Ta at 25 ° C. is 1.0 MPa or more and 20.0 MPa or less, and when 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 90 ° C dimensional change rate 1, the direction at which the 90 ° C dimensional change rate 1 is the maximum is the X direction, the direction orthogonal to the X direction in the film plane is the Y direction, and the 90 ° dimensional change in the X direction is 90 ° C. A film characterized in that Tx1 is -10.00% or more and 10.00% or less when the ratio is Tx1 (%). Provided is a film suitable as a substrate for a semiconductor manufacturing process, having heat resistance enough to maintain planarity in a heating process and sufficient flexibility to be used as an adhesive film for dicing or the like.

Description

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

  Conventionally, highly flexible film members that can be stretched with a low load even at room temperature have been applied to various products such as base materials such as adhesive tapes, transfer base materials for molding, and cushioning materials during pressing. It is also used in a wide range of fields such as circuit and semiconductor manufacturing processes and decoration.

  For example, in the process of manufacturing a semiconductor, a process of attaching an adhesive tape for processing a semiconductor wafer to a pattern surface of a semiconductor wafer, a back grinding process of polishing the back surface of the semiconductor wafer to reduce the thickness, and reducing the thickness in the process. There are various processes such as a process of mounting a semiconductor wafer on a dicing tape, a process of separating the semiconductor wafer processing adhesive tape from the semiconductor wafer, and a process of dividing the semiconductor wafer by dicing.

  In recent years, semiconductor wafers have become thinner with the downsizing of electronic devices, and their strength has been reduced. Therefore, the semiconductor wafers are liable to be damaged during the manufacturing process, and a reduction in yield has been a problem. For example, after the dicing step, a pressure-sensitive adhesive film having excellent flexibility is required which alleviates a load on a semiconductor wafer generated in a step of radially expanding the dicing adhesive film and picking up individual chips. As a method of increasing the flexibility of the pressure-sensitive adhesive film, for example, a film mainly composed of a resin having excellent flexibility such as a polypropylene-based resin or an olefin-based elastomer, and a styrene-based elastomer is used as a base film of the pressure-sensitive adhesive film. The method used is known (Patent Document 1).

  In some cases, a step of bonding a dicing adhesive film to the semiconductor wafer surface polished in the back grinding step and peeling the back grinding sheet by thermal peeling may be used. At that time, if the dimensional stability of the adhesive film for dicing, which is heated at the same time, is insufficient, the film is deformed, and there is a problem that wrinkles and loosening occur. In order to solve such a problem, for example, a film in which heat shrinkage is controlled has been proposed as a base material of an adhesive film for a dicing tape (Patent Document 2).

JP 2011-119548 A JP 2014-157964 A

  However, since the base material used for the pressure-sensitive adhesive tape described in Patent Document 1 or Patent Document 2 is a non-stretched film obtained by an extrusion method, there is a problem that the film expands under tension and loses the flatness of the film. is there. Conventionally, a non-stretched film used as a base film such as a pressure-sensitive adhesive film for dicing expands the film when heated under a low load, so that it is difficult to apply the film to a semiconductor manufacturing process. On the other hand, a film having high dimensional stability, such as a biaxially stretched film, can reduce deformation during heating, but lacks flexibility. As described above, conventionally known films cannot satisfy both the heat resistance and the flexibility required for a substrate for a semiconductor manufacturing process, and improvements have been desired.

  The present invention solves the above-mentioned problems of the prior art, and has sufficient heat resistance to maintain flatness in the heating step, and sufficient flexibility to be used as an adhesive film for dicing. An object of the present invention is to provide a film suitable as a substrate for a semiconductor manufacturing process.

  In order to solve such a problem, the present invention has the following configuration.

(1) The stress Ta at 5% elongation at 25 ° C. is 1.0 MPa or more and 20.0 MPa or less, and a load of 120 g / mm ² is applied to increase the temperature from 25 ° C. to 160 ° C. at a rate of 10 ° C./min. The dimensional change rate at 90 ° C. when heated is 90 ° dimensional change rate 1, the direction in which the 90 ° dimensional change rate 1 is maximum is the X direction, the direction orthogonal to the X direction in the film plane is the Y direction, and the X direction is the X direction. A film, wherein Tx1 is -10.00% or more and 10.00% or less when a 90 ° C dimensional change rate is Tx1 (%).

(2) The dimensional change rate at 90 ° C. when the temperature was raised from 25 ° C. to 160 ° C. at a rate of 10 ° C./min by applying a load of 5 g / mm ² was 90 ° C. dimensional change rate 2 in the X direction. The film according to (1), wherein Tx2 is -10.00% or more and 1.00% or less, where 90 ° C dimensional change 2 is Tx2 (%).

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

  (4) Any one of (1) to (3), wherein when the layer having a glass transition temperature of −40 ° C. or more and 40 ° C. or less is the A layer, the layer has at least one A layer. Film.

(5) When the dimensional change rate 1 at 90 ° C. in the Y direction is Ty1 (%), the Tx1 and Ty1 satisfy the following equation (1). The film as described.
Formula 1: 0.10 ≦ | Tx1-Ty1 | ≦ 3.00
(6) The film according to any one of (1) to (5), wherein a coefficient of static friction measured by overlapping different surfaces of the film is not less than 0.10 and not more than 0.80.

(7) The film according to any one of (1) to (6), wherein at least one surface has a surface roughness SRa (μm) and a ten-point average roughness SRzjis (μm) satisfying the following expression 2. .
Formula 2: 5.0 ≦ SRzjis / SRa ≦ 25.0
(8) Any one of (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 1.

  (9) The film according to any one of (1) to (8), wherein a shrinkage ratio when heated at 80 ° C. for 1 hour is more than 1.00% and not more than 10.00%.

(10) The method according to any one of (1) to (9), wherein the Ta and the stress Tb at 5% elongation at 25 ° C. after heating at 90 ° C. for 10 minutes satisfy the following expression 3. the film.
Formula 3: 0.85 ≦ Tb / Ta ≦ 1.30
(11) The film according to any one of (1) to (10), wherein the maximum stress Ka at 50% elongation at 25 ° C. and the stress Kb at 50% elongation satisfy the following expression 4.
Formula 4: 0.70 ≦ Kb / Ka ≦ 1.00
(12) The film according to any one of (1) to (11), wherein a dimensional change rate 1 at 90 ° C. 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 a dimensional change rate 2 at 90 ° C. in all directions is −25.00% or more and 1.00% or less.

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

  (15) The film according to any one of (1) to (14), wherein the thickness unevenness is 10.0% or less.

  (16) The method for producing a film according to any one of (1) to (15), comprising a step of stretching in at least one direction at a magnification of 1.04 or more and 2.00 or less. A method of manufacturing a film.

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

The film of the present invention has a stress Ta at 5% elongation at 25 ° C. of 1.0 MPa or more and 20.0 MPa or less, a load of 120 g / mm ² , and a temperature rise rate of 10 ° C./min from 25 ° C. to 160 ° C. The dimensional change rate at 90 ° C. when the temperature is raised by 90 minutes is 90 ° dimensional change rate 1, the direction in which the 90 ° dimensional change rate 1 is the maximum is the X direction, the direction orthogonal to the X direction in the film plane is the Y direction, Tx1 is not less than -10.00% and not more than 10.00% when the dimensional change rate at 90 ° C. in the X direction is Tx1 (%).

  In the film of the present invention, from the viewpoint of improving heat resistance and reducing chip damage in the semiconductor manufacturing process, it is important that the stress Ta at 5% elongation at 25 ° C. is 1.0 MPa or more and 20.0 MPa or less. If the stress Ta at 5% elongation at 25 ° C. (hereinafter sometimes simply referred to as Ta) is less than 1.0 MPa, the film may be deformed at the time of heating due to the mass of the semiconductor wafer, or may not be expanded when the film is expanded. May deform evenly. On the other hand, if Ta is larger than 20.0 MPa, the load at the time of picking up the chip is large, and the chip may be damaged. From the above viewpoint, Ta is more preferably 1.5 MPa or more and 15.0 MPa or less, and further preferably 2.0 MPa or more and 10.0 MPa or less. The method for setting Ta to the above range is not particularly limited, and for example, a method of forming a cast film having at least one layer having a glass transition temperature of −50 ° C. or more and 50 ° C. or less, preferably an A layer described below, or a cast film Is stretched in at least one direction at a magnification of 2.00 or less.

  The “stress Ta at 5% elongation at 25 ° C.” refers to a stress at 5% elongation at 25 ° C. measured at a test speed of 300 mm / min according to JIS K7127 (1999, specimen type 2). Further, “5% elongation stress at 25 ° C. at the time of 5% elongation is 1.0 MPa or more and 20.0 MPa or less” means that any direction parallel to the film surface is 0 ° direction, and 0 ° direction is parallel to the film surface. Assuming that the direction rotated 175 ° clockwise is the 175 ° direction, the test speed is 300 mm according to JIS K7127 (1999, test piece type 2) at 5 ° intervals in the range from the 0 ° direction to the 175 ° direction. Per minute at 5% elongation at 25 ° C. means that the maximum value of the 36 measured values obtained is 1.0 MPa or more and 20.0 MPa or less. In addition, a rectangular sample of 150 mm (measurement direction) × 10 mm (a direction perpendicular to the measurement direction) is used as an evaluation sample.

The film of the present invention has a dimensional change at 90 ° C. when the temperature is increased from 25 ° C. to 160 ° C. at a rate of 10 ° C./min under a load of 120 g / mm ² , and the dimensional change at 90 ° C. is 1,90. When the direction at which the dimensional change rate 1 ° C. becomes maximum is the X direction, the direction orthogonal to the X direction in the film plane is the Y direction, and the dimensional change rate at 90 ° C. in the X direction is Tx1 (%), Tx1 is −10. It is important that the content be 0.000% or more and 10.00% or less. By setting Tx1 within the above range, it is possible to reduce the deformation when the semiconductor wafers are stacked and the film is heated while an elongation load is applied. If Tx1 is less than -10.00%, wrinkles may occur due to shrinkage of the film, and if Tx1 is more than 10.00%, the fixing position of the semiconductor wafer fluctuates due to expansion of the film, and Failure may occur in the process. From the above viewpoint, Tx1 is preferably from -10.00% to 1.00%, more preferably from -8.00% to 1.00%, and more preferably from -4.50% to -1.00%. It is more preferable that the following is satisfied.

The film of the present invention has a dimensional change rate of 90 ° C. when the temperature is raised from 25 ° C. to 160 ° C. at a rate of 10 ° C./min under a load of 5 g / mm ² , and the dimensional change rate is 90 ° C. When the dimensional change rate 2 at 90 ° C. in the X direction is Tx2 (%), it is preferable that Tx2 be -10.00% or more and 1.00% or less. By setting Tx2 within the above range, it is possible to reduce deformation due to heating even when the load applied to the film is small. By setting Tx2 to -10.00% or more, generation of wrinkles due to shrinkage of the film can be reduced. Further, by setting Tx2 to 1.00% or less, it is possible to reduce the occurrence of problems in the post-process due to the fluctuation of the fixing position of the semiconductor wafer due to the expansion of the film. From the above viewpoint, Tx2 is more preferably −8.00% or more and 0.00% or less, and still more preferably −4.50% or more and −1.00% or less.

“90 ° C. dimensional change 1” can be measured by the following procedure. First, a film sample cut into a size of 15 mm (measurement direction) × 4 mm (a direction perpendicular to the measurement direction) in a room temperature environment was allowed to stand for 24 hours in an atmosphere at a temperature of 25 ° C. and a relative humidity of 65%. The length (L ₀ ) in the measurement direction is measured. Next, the film sample is heated from 25 ° C. to 160 ° C. with a load of 120 g / mm ² at a rate of 10 ° C./min, and the length (L ₁ ) at 90 ° C. in the measurement direction is measured. From the obtained values of L ₀ and L _1, a 90 ° C. dimensional change rate 1 is determined by the following equation 5.
Formula 5: 90 ° C. dimensional change rate 1 (%) = (L ₁ −L ₀ ) × 100 / L ₀ .

  The apparatus used for measuring the dimensions for calculating the dimensional change rate 1 at 90 ° C. is not particularly limited as long as the effects of the present invention are not impaired. For example, a thermal analyzer TMA / SS6000 (manufactured by Seiko Instruments Inc.) may be used. Can be. In the X direction, measure the dimensional change rate 1 at 90 ° C. in an arbitrary direction parallel to the film surface, and then rotate it clockwise 5 ° in parallel with the film surface to make the angle with the first selected direction 175 °. When the 90 ° C. dimensional change rate 1 is measured in the same manner until reaching, the direction of the 90 ° C. dimensional change rate 1 is the largest. The value of the dimensional change rate 1 at 90 ° C. at that time is defined as Tx1 (%). Here, “the value of the 90 ° C. dimensional change rate 1 is the largest” means that the value of the 90 ° C. dimensional change rate 1 obtained by Equation 5 is the largest. For example, if the measured 90 ° C dimensional change 1 in all directions is in the range of −5.00% to 3.00%, the direction in which the 90 ° C dimensional change 1 is 3.00% is the X direction.

  However, when there are a plurality of directions in which the value of the 90 ° C. dimensional change rate 1 obtained by Equation 5 is the largest, the 90 ° C. in the direction orthogonal to each measurement direction is obtained from the value of the 90 ° C. dimensional change rate 1 in each measurement direction. The absolute value of the value obtained by subtracting the value of the dimensional change rate 1 is determined, and the absolute value is in the range of 0.10% to 3.00% and the smallest direction is defined as the X direction. Can be. If the absolute value is out of the range of 0.10% to 3.00% in any measurement direction, the absolute value is closest to the range of 0.10% to 3.00%. Let the direction be the X direction.

The “90 ° C. dimensional change rate 2” refers to a dimensional change rate measured by the same method as the 90 ° C. dimensional change rate 1 except that the magnitude of the load is 5 g / mm ^2. The same device as that of the dimensional change rate of 1 ° C. can be used.

  The method for setting Tx1 to -10.00% or more and 10.00% or less or the above preferable range is not particularly limited as long as the effects of the present invention are not impaired. For example, the glass transition temperature is -50 ° C or more and 50 ° C or less. A method in which a cast film having at least one layer is stretched in at least one direction at a magnification of 1.04 to 2.00 times, etc. The method for setting Tx2 to -10.00% or more and 1.00% or less or the above preferable range is not particularly limited as long as the effects of the present invention are not impaired. At a temperature of 1.04 to 2.00 times at least in one direction.

  The value of the 90 ° C. dimensional change rate 1 in a direction other than the X direction is not particularly limited as long as the effects of the present invention are not impaired. However, from the viewpoint of reducing the dimensional change when heated by applying a load, the dimensional change rate 1 at 90 ° C. in all directions is preferably −25.00% or more and 10.00% or less, and −15.00%. It is preferably at least 1.00% and more preferably at least -10.00% and at most -1.00%. By adopting such an aspect, when the semiconductor wafer is laminated and heated in a state where an elongation load is applied to the film, excessive deformation of the film is suppressed, so that the dimensional stability required in the semiconductor manufacturing process can be easily achieved. realizable.

  The value of the 90 ° C. dimensional change 2 in directions other than the X direction is not particularly limited as long as the effects of the present invention are not impaired. However, from the viewpoint of reducing the dimensional change upon heating even when the load applied to the film is small, the 90 ° C. dimensional change rate 2 in all directions may be −25.00% or more and 1.00% or less. Preferably, it is -15.00% or more and 0.00% or less, and more preferably -10.00% or more and -1.00% or less. By adopting such an aspect, even when the semiconductor wafers are laminated and heated under a small load on the film, excessive deformation of the film is suppressed, so that the dimensional stability required in the semiconductor manufacturing process can be easily achieved. Can be realized.

The film of the present invention preferably has at least one surface orientation coefficient of 0.0080 or more and 0.0800 or less. The plane orientation coefficient is an index indicating the degree of orientation of the polymer within the film plane, and a larger plane orientation coefficient means a higher orientation state. Here, the plane orientation coefficient (fn) refers to a plane orientation coefficient measured by the following method. First, α is an arbitrary direction parallel to the film surface, β is a direction orthogonal to the film surface, and γ is a direction (thickness direction) orthogonal to α and β, and the refractive index (nα, nβ, nγ) is measured with an Abbe refractometer. Using the obtained values, the plane orientation coefficient (fn ₀ ) when the two directions on the film surface are α and β is calculated by the following equation 6.
Equation 6: fn ₀ = (nα + nβ) / 2−nγ.

Then, γ is fixed and α and β are rotated clockwise by 5 ° while maintaining the parallelism with the film surface, respectively, to obtain nα5 and nβ5, and the refractive index (nα5, nβ5, nγ) in each direction is Abbe. The surface orientation coefficient (fn ₅ ) when the two directions on the film surface are α5 and β5 is determined by measuring with a refractometer and replacing nα with nα5 and nβ5 with nβ5 in Equation 6 above. Hereinafter, the same measurement is repeated until the two directions on the film surface become α85 and β85. The average value of the 18 measured values from fn ₀ to fn ₈₅ is the plane orientation coefficient (fn).

  In the case of a film having a plane orientation coefficient of less than 0.0080, that is, a film in a non-oriented state or an almost non-oriented state, the flexibility is sufficient but the heat resistance may be poor. On the other hand, when the plane orientation coefficient exceeds 0.0800, the degree of orientation is increased and thus the heat resistance is excellent, but the flexibility may be insufficient. In light of achieving both the flexibility and the heat resistance of the film, the film of the present invention preferably has at least one surface orientation coefficient of 0.0120 or more and 0.0600 or less, and 0.0150 or more and 0.0400 or less. It is more preferred that there be.

  The method for setting the plane orientation coefficient of at least one surface of the film of the present invention to 0.0080 or more and 0.0800 or less or the above preferable range is not particularly limited as long as the effects of the present invention are not impaired. A method of stretching in at least one direction at a magnification of 04 times or more and 2.00 times or less is exemplified. By stretching at such a low magnification, the molecules of the resin can be oriented to such an extent that the flexibility of the film is not impaired. From the above viewpoint, when stretching in two or more directions, the area stretching ratio obtained by multiplying the stretching ratio in each direction is preferably from 1.20 to 1.80, and more preferably from 1.40 to 1.80. More preferably, it is not more than 70 times.

  The film of the present invention preferably has at least one layer A when the layer having a glass transition temperature of −40 ° C. or more and 40 ° C. or less is the layer A. By having the A layer, the film has sufficient flexibility even at room temperature. In addition, by controlling the orientation state of the molecules in an appropriate range for realizing the flexibility and heat resistance aimed at by the present invention, in combination with stretching at a magnification of 1.04 to 2.00, which will be described later. Can be. Here, the glass transition temperature means a temperature determined based on measurement of a calorific value change (DSC method) by differential scanning calorimetry (DSC) in accordance with JIS K7121 (2012). From the viewpoint of achieving both flexibility and heat resistance, the glass transition temperature of the layer A is more preferably from −25 ° C. to 20 ° C., and even more preferably from −10 ° C. to 5 ° C.

  The resin used for the film of the present invention is not particularly limited as long as the effects of the present invention are not impaired. For example, polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyarylate, Polyethylene, polypropylene, polyamide, polyimide, polymethylpentene, polyvinyl chloride, polystyrene, polymethyl methacrylate, polycarbonate, polyetheretherketone, polysulfone, polyethersulfone, fluororesin, polyetherimide, polyphenylenesulfide, polyurethane, and cyclic An olefin-based resin or the like can be used alone or in combination. Above all, polyesters such as polyethylene terephthalate and polybutylene terephthalate, and polyolefins such as polypropylene are preferably used from the viewpoints of handleability, dimensional stability, and economical efficiency during production.

  In the present invention, the polyester is a generic term for polymers having a main bond in the main chain as an ester bond. Usually, a polyester can be obtained by subjecting a dicarboxylic acid component and a glycol component to a polycondensation reaction.

  The dicarboxylic acid component for obtaining the polyester is not particularly limited as long as the effects of the present invention are not impaired, and for example, terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid Aromatic dicarboxylic acids such as diphenoxyethane dicarboxylic acid and 5-sodium sulfone dicarboxylic acid; aliphatic dicarboxylic acids such as oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid and fumaric acid; -Each component such as an alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid and an oxycarboxylic acid such as paraoxybenzoic acid can be used. The dicarboxylic acid component may be a dicarboxylic acid ester derivative component, and an esterified product of the dicarboxylic acid compound, for example, dimethyl terephthalate, diethyl terephthalate, 2-hydroxyethyl methyl terephthalate, 2,6-naphthalenedicarboxylic acid Each component such as dimethyl, dimethyl isophthalate, dimethyl adipate, diethyl maleate and dimethyl dimer can also be used.

  The glycol component for obtaining the polyester is not particularly limited as long as the effects of the present invention are not impaired. For example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, Aliphatic dihydroxy compounds such as 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetra Various components such as polyoxyalkylene glycols such as methylene glycol, alicyclic dihydroxy compounds such as 1,4-cyclohexanedimethanol and spiro glycol, and aromatic dihydroxy compounds such as bisphenol A and bisphenol S can be used. Among them, ethylene glycol, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, 1,4-cyclohexanedimethanol, and poly (ethylene glycol), 1,4-butanediol, It is preferable to use each component of tetramethylene glycol.

  Two or more of these dicarboxylic acid components and glycol components may be used in combination as long as the effects of the present invention are not impaired.

  Polyolefins that can be preferably used in the present invention include, for example, propylene homopolymers and propylene / α-olefin copolymers exhibiting isotactic or syndiotactic stereoregularity. Specific examples of the α-olefin include, for example, ethylene, 1-butene, 1-pentene, 3-methylpentene-1, 3-methylbutene-1, 1-hexene, 4-methylpentene-1, 5-ethylhexene- Examples thereof include 1,1-octene, 1-decene, 1-dodecene, vinylcyclohexene, styrene, allylbenzene, cyclopentene, norbornene, and 5-methyl-2-norbornene. The propylene / α-olefin copolymer contains more than 50 mol% of propylene units when all the constituent units constituting the polymer are 100 mol% from the viewpoint of improving handling during processing. preferable. 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. Any of these may be used. These propylene homopolymers and propylene / α-olefin copolymers may be used as a mixture of two or more kinds as long as the object of the present invention is not impaired.

  In addition, for the purpose of improving the flexibility of the film, it is also a preferable embodiment to blend a hydrocarbon elastomer with polyolefin. Examples of the hydrocarbon elastomer include styrene / butadiene copolymer (SBR), styrene / isobutylene / styrene copolymer (SIS), styrene / butadiene / styrene copolymer (SBS), and hydrogenated styrene / butadiene copolymer ( Styrene-conjugated diene copolymers such as HSBR) and hydrogenated products thereof, styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-isobutylene copolymer, and mixtures thereof. These hydrocarbon elastomers may be used alone or in combination of two or more as long as the effects of the present invention are not impaired.

  The method for setting the glass transition temperature of the A layer to −40 ° C. or more and 40 ° C. or less or the above preferred range is not particularly limited as long as the effects of the present invention are not impaired. A method using a material in the range of 40 ° C. or more and 40 ° C. or less or the above-mentioned preferable range may be mentioned. The glass transition temperature of the A layer is increased by setting the resin constituting the A layer to have a high glass transition temperature or by raising the ratio of the resin having the high glass transition temperature to the entire resin constituting the A layer. be able to.

From the viewpoint of improving the heat resistance and reducing the deformation due to the weight of the semiconductor wafer, the film of the present invention has Tx1 and Ty1 represented by the following formulas when the dimensional change rate 1 at 90 ° C. in the Y direction is Ty1 (%). It is preferable to satisfy 1.
Formula 1: 0.10 ≦ | Tx1-Ty1 | ≦ 3.00.

  | Tx1−Ty1 | is an index representing the variation in the direction of the dimensional change rate 1 at 90 ° C. in the plane. More specifically, as | Tx1-Ty1 | is larger, the variation in the 90 ° C. dimensional change rate 1 in the X and Y directions is larger, and as | Tx1-Ty1 | is smaller, the 90 ° C. dimensional change rate in the X and Y directions is larger. 1 means that the variation is small. When | Tx1−Ty1 | is 0.10 or more and 3.00 or less, the flatness of the film during heating can be further improved. That is, by making the deformation of the film non-uniform so as not to be excessive during heating, the effect of maintaining the flatness of the film due to a dimensional change is likely to appear. When | Tx1−Ty1 | is greater than 3.00, the deformation of the film during heating becomes excessively non-uniform depending on the direction, so that wrinkles and looseness may be likely to occur. When | Tx1−Ty1 | is less than 0.10 and the in-plane deformation does not substantially depend on the direction, the tension may decrease near the center of the fixed sample, and the deformation may be caused by the weight of the semiconductor wafer. There is. From the above viewpoint, | Tx1−Ty1 | is more preferably 0.10 or more and 2.20 or less. As a method for setting | Tx1−Ty1 | to 0.10 or more and 3.00 or less or the preferable range described above, for example, a method of biaxially stretching a cast film having the above-mentioned layer configuration may be mentioned. More specifically, the value of | Tx1−Ty1 | can be reduced by reducing the difference in the stretching ratio in each direction when the film is biaxially stretched.

  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 both surface layers the same or to make the lamination thickness of both surface layers equal.

  The film of the present invention has a static friction coefficient of 0.10 or more and 0.80 or less measured by overlapping different surfaces of the film from the viewpoint of improving handling and stretching accuracy during production and reducing occurrence of scratches on the surface. Is preferred. Here, the coefficient of static friction refers to a coefficient of static friction measured by arranging two films so that their opposite sides overlap each other and rubbing at a speed of 100 mm / min according to JIS K7125 (1999). By setting the coefficient of static friction measured by superimposing different surfaces of the film on each other, the handling at the time of production becomes good, and it is possible to improve the stretching accuracy when stretching by a roll, and also to improve the surface. Can be reduced. In the production process of the film of the present invention, it is required to appropriately control the draw ratio in a low region as described above. If the coefficient of static friction exceeds 0.80, especially when the friction with the roll is excessive, the draw ratio may be higher than designed, or the film surface may be damaged. When the coefficient of static friction is less than 0.10, the roll is likely to be displaced, and the productivity may be reduced. From the above viewpoint, the coefficient of static friction measured by superposing different surfaces of the film on each other is more preferably 0.10 or more and 0.70 or less, further preferably 0.10 or more and 0.60 or less.

  The method of adjusting the coefficient of static friction to 0.10 or more and 0.80 or less or the preferable range is not particularly limited as long as the effects of the present invention are not impaired, but when the film has a single-layer structure, In the case of a laminated structure, a method in which at least one outermost layer contains inorganic particles and / or organic particles having an average particle size of 1 μm or more and 10 μm or less can be used. More specifically, the static friction coefficient can be reduced by increasing the content of these particles. Here, the average particle size means a volume average particle size. In addition, a method of blending a polyolefin with a hydrocarbon elastomer having different crystallinity is also preferably used. By blending resins having different crystallinity, fine irregularities can be formed on the surface due to the difference in crystal growth and elongation during casting, and the static friction coefficient can be set in a preferable range.

  Examples of the particles include inorganic particles such as wet and / or dry silica, colloidal silica, aluminum silicate, titanium oxide, calcium carbonate, calcium phosphate, barium sulfate, alumina, mica, kaolin, clay, and hydroxyapatite, styrene, silicone, and acrylic. Polymerized acid, methacrylic acid, divinylbenzene, or the like, or organic particles containing polyester, polyamide, or the like as a component can be used. Among them, inorganic particles such as wet and / or dry silica and alumina, those obtained by polymerizing styrene, silicone, acrylic acid, methacrylic acid, divinylbenzene and the like, and organic particles containing polyester, polyamide and the like as components are preferably used. You. As the particles, two or more kinds of internal particles, inorganic particles and organic particles may be used, or two or more kinds of internal particles, inorganic particles and organic particles may be used in combination.

  Further, the content of the particles is preferably in the range of 0.01 to 5% by mass, more preferably 0.03 to 3% by mass, based on the entire resin composition constituting the outermost layer of the film. . If the amount is less than 0.01% by mass, winding of the film may be difficult. If the amount is more than 5% by mass, the glossiness may be reduced due to the coarse projections, and the transparency and the film-forming property may be deteriorated.

It is preferable that the film of the present invention has a surface roughness SRa (μm) and a ten-point average roughness SRzjis (μm) satisfying the following expression 2 on at least one surface.
Formula 2: 5.0 ≦ SRzjis / SRa ≦ 25.0.

  By adopting such an embodiment, the uniformity of the uneven shape on the film surface can be enhanced, and the adhesion between the film and the adhesive layer during the adhesive processing can be improved. By setting SRzjis / SRa to 25.0 or less, it is possible to reduce the inhibition of adhesion to the adhesive layer due to the coarse projections, and to shorten the aging time at the time of processing the adhesive layer, thereby improving the productivity. Further, setting SRzjis / SRa to less than 5.0 is difficult to realize in a manufacturing method usually used because slip occurs during film formation, and even if it can be realized, blocking or the like may occur. is there. From the above viewpoint, SRzjis / SRa is more preferably 5.0 or more and 22.0 or less, and further preferably 5.0 or more and 18.0 or less.

  The method for setting SRzjis / SRa to 5.0 or more and 25.0 or less or the above-mentioned preferable range is not particularly limited as long as the effects of the present invention are not impaired. And a method in which the obtained cast film is stretched in at least one direction at a low magnification of 1.04 to 2.00 times. Specifically, for example, SRzjis / SRa can be reduced by blending a hydrocarbon-based elastomer with the above-described polyolefin and increasing the draw ratio within the above-described range. By stretching at such a low magnification, it becomes easy to control and uniform the size and number of projections. Further, since the degree of orientation of the molecules is increased by the stretching, the strength of the projections is improved, and the change in the surface shape due to the scraping during the process can be reduced. Further, as a method for setting SRzjis / SRa to 5.0 or more and 25.0 or less or the preferable range described above, a method in which stretching is performed in two or more stages and a method in which simultaneous biaxial stretching is performed can also be employed. .

The film of the present invention preferably has a heat shrinkage stress at 90 ° C. in the X direction and the Y direction of 0.010 N / mm ² or more and 5.000 N / mm ² or less. By adopting such an embodiment, even when a load is applied to the film such as when the wafers are stacked, it is possible to reduce the elongation and the expansion and deformation of the film when heated. By setting the heat shrinkage stress at 90 ° C. to 0.010 N / mm ² or more, it is possible to reduce a decrease in the positional accuracy of the wafer due to a dimensional change during heating and to reduce the occurrence of wrinkles due to shrinkage deformation in the plane. it can. Further, by setting the heat shrinkage stress at 90 ° C. to 5.000 N / mm ² or less, the peeling and breakage of the wafer due to the stress generated on the wafer contact surface due to the shrinkage can be reduced. In view of the above, the thermal shrinkage stress of 90 ° C. in the X and Y directions more preferable to be 0.030N / mm ² or more 4.000N / mm ² or more, 0.050N / mm ² or more 3.300N / mm ² More preferably, it is the above.

Here, the heat shrinkage stress at 90 ° C. can be measured by the following method. First, a film of 15 mm (measurement direction) × 4 mm (a direction perpendicular to the measurement direction) is allowed to stand in an atmosphere of 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 rate of 10 ° C./min, and the heat shrinkage stress at 90 ° C. was measured. The load at the start of the measurement is 5 g / mm ² . The apparatus used for measuring the heat shrinkage stress at 90 ° C. is not particularly limited as long as it can perform the above measurement, and can be appropriately selected. For example, TMA / SS6000 (manufactured by Seiko Instruments Inc.) can be used.

The method for setting the heat shrinkage stress at 90 ° C. in the X direction and the Y direction at 0.010 N / mm ² or more and 5.000 N / mm ² or less in the preferable range is not particularly limited as long as the effects of the present invention are not impaired. For example, in a cast film having at least one layer A, the glass transition temperature of layer A is -30 ° C or more and 40 ° C or less, and stretched in at least one direction at a magnification of 1.04 or more and 2.00 or less. And the like.

  The film of the present invention preferably has a shrinkage ratio of more than 1.00% and not more than 10.00% when heated at 80 ° C. for 1 hour. By adopting such an embodiment, it is possible to reduce deformation when heated even in a heating process at a low temperature. When the shrinkage ratio when heated at 80 ° C. for 1 hour is 1.00% or less, it may be difficult to suppress a dimensional change during heating. If the shrinkage ratio after heating at 80 ° C. for 1 hour is more than 10.00%, the shrinkage occurs when heated in an adhesive processing step or the like, and the dimensional change occurs when heated in a subsequent semiconductor manufacturing process. May be larger. The shrinkage when heated at 80 ° C. for 1 hour is more preferably 2.00% or more and 8.00% or less, further preferably 3.00% or more and 6.00% or less. The method of setting the shrinkage when heated at 80 ° C. for 1 hour to more than 1.00% and not more than 10.00% or the above preferable range is not particularly limited as long as the effects of the present invention are not impaired. A method in which the film is stretched in at least one direction at a magnification of 1.40 times or more and 2.00 times or less can be used.

In the film of the present invention, it is preferable that the stress Tb at 5% elongation at 25 ° C. after heating at 90 ° C. for 10 minutes with Ta satisfies the following formula 3.
Formula 3: 0.85 ≦ Tb / Ta ≦ 1.30.

  When Tb / Ta satisfies the expression 3, it means that a change in elongation characteristics after heating is small. By adopting such an embodiment, the film can be preferably used even when expanding after the heating step. From the above viewpoint, Tb / Ta is more preferably 0.85 or more and 1.23 or less, further preferably 0.85 or more and 1.15 or less. The method of setting Tb / Ta to 0.85 or more and 1.30 or less or the above preferable range is not particularly limited as long as the effects of the present invention are not impaired. Examples of the method include a method of performing processing. The heat treatment can be performed by a conventionally known method such as a roll annealing or a tenter method, and the stretching may be performed simultaneously with the heating as long as the effects of the present invention are not impaired.

In the film of the present invention, the maximum stress Ka at 50% elongation and the stress Kb at 50% elongation at 25 ° C. preferably satisfy the following formula 4.
Equation 4: 0.70 ≦ Kb / Ka ≦ 1.00.

  When Kb / Ka satisfies Equation 4, it means that the yield point stress is small or substantially not generated when the film is stretched at room temperature. When the yield point stress is high, unevenness in thickness and unevenness of stress at the central portion and at the end portion at the time of expansion tend to affect the degree of elongation, and the uniformity of in-plane elongation may be reduced. Therefore, by adopting such an embodiment, the uniformity of in-plane elongation can be further improved. From the above viewpoint, Kb / Ka is more preferably 0.80 or more and 1.00 or less, further preferably 0.90 or more and 1.00 or less. The method for setting Kb / Ka to a preferable range is not particularly limited as long as the effects of the present invention are not impaired. For example, a method in which a cast film is biaxially stretched at an area magnification of 1.04 to 2.00 times. Can be

In the film of the present invention, from the viewpoint of reducing the reduction in the yield in wafer dicing, the number of adhered foreign substances having a diameter of 100 μm or more is preferably 10 / m ² or less, more preferably 2 / m ² or less. Here, the diameter of the foreign substance is a distance between two points on the contour of the foreign substance, the value of which is the maximum. When the number of adhered foreign particles having a diameter of 100 μm or more is 10 particles / m ² or less, occurrence of chipping during wafer dicing can be suppressed, and a decrease in yield can be reduced. The method for setting the number of adhered foreign substances having a diameter of 100 μm or more to 10 particles / m ² or less or the above preferred range is not particularly limited as long as the effects of the present invention are not impaired. A method of removing adhering foreign matter by installing an adhesive roll or a dust remover, a method of stretching under an environment of hot air using an oven, and the like. The smaller the number of adhered foreign substances having a diameter of 100 μm or more, the better, and the lower limit is most preferably 0 / m ² .

The number of adhered foreign substances having a diameter of 100 μm or more can be measured by the following procedure. First, a visual inspection is performed using reflected light of a three-wavelength fluorescent lamp in a dark room to extract foreign substances on a film sample. When a foreign substance is observed, the foreign substance is observed under magnification with an electron microscope, the length of the major axis is measured, and only the substance whose major axis is 100 μm is extracted again. Thereafter, the number of extracted foreign substances is divided by the area of the film sample to determine the number of attached foreign substances having a diameter of 100 μm or more (pieces / m ² ).

  The film of the present invention preferably has a thickness unevenness of 10.0% or less from the viewpoint of reducing a decrease in yield in wafer dicing. When the thickness unevenness is 10.0% or less, the frequency of occurrence of chipping due to rattling at the time of wafer dicing is reduced, the reduction in yield is reduced, and the uniformity during expansion is improved. From the above viewpoint, the thickness unevenness is more preferably 8.0% or less. The method for controlling the thickness unevenness to 10.0% or less or the above preferable range is not particularly limited as long as the effects of the present invention are not impaired. For example, a method of stretching at a stretching ratio of 1.04 to 2.00 times and the like is exemplified. No. By stretching under such conditions, thickness unevenness can be reduced while suppressing a decrease in flexibility. When the stretching ratio is less than 1.04, the thickness unevenness of the cast film is hardly eliminated, and when the stretching ratio is 2.00 or more, the thickness unevenness may be increased. The smaller the thickness unevenness, the better, and the lower limit is most preferably 0.0%. As a stretching condition, a method of reducing the stretching tension by setting the stretching temperature to 90 ° C. or higher and the melting point of the film is also preferably used.

  Next, a method for producing the film of the present invention will be described. The method for producing a film of the present invention is characterized by comprising a step of stretching in at least one direction at a magnification of 1.04 or more and 2.00 or less. By adopting such an embodiment, dimensional stability during heating is improved. In view of the above, it is preferable to include a step of stretching in at least one direction at a magnification of 1.20 to 1.80 times, and to stretch in at least one direction at a magnification of 1.40 to 1.70 times. It is more preferred to have In the method for producing a film of the present invention, the film may be biaxially stretched as long as the effects of the present invention are not impaired.

  Hereinafter, the method for producing a film of the present invention will be specifically described with reference to a single-layer film made of polyester as an example, but the present invention is not construed as being limited to such an example.

  First, polyester is supplied to a twin-screw extruder and melt-extruded. At this time, it is preferable to control the oxygen concentration to 0.7 volume% or less in a flow nitrogen atmosphere in the extruder and to control the extrusion temperature to a range higher by 20 to 30 ° C. than the melting point of the polyester. Next, the foreign matter is removed and the amount of the extruded material is evened out through a filter or a gear pump, and then discharged from the T-die into a sheet on a cooling drum. At this time, an electrostatic application method in which the cooling drum and the resin are brought into close contact with each other by static electricity using an electrode to which a high voltage is applied, a casting method in which a water film is provided between the casting drum and the extruded polymer sheet, and a casting drum temperature of polyester glass A sheet-like polymer is adhered to a casting drum by a method of adhering an extruded polymer with a transition point of −20 ° C. or more and a glass transition temperature or less, or a combination of these methods, and is cooled and solidified to obtain a casting film. . Among these casting methods, the electrostatic application method is preferably used from the viewpoint of productivity and flatness.

  In the method for producing a film of the present invention, for the purpose of imparting dimensional stability during heating, the film is stretched in at least a uniaxial direction at a magnification of 1.04 to 2.00. The stretching ratio in the case of stretching in the uniaxial direction is preferably from 1.20 to 1.80, and more preferably from 1.40 to 1.70. Further, when the film is stretched in the biaxial direction, it is a preferred embodiment that the area magnification is in the above range. Also, the stretching speed is desirably 100% / min to 200,000% / min. Stretching can be performed at any temperature of room temperature or higher, but is preferably 20 ° C. or higher and 160 ° C. or lower, and is preferably preheated for 1 second or longer before stretching. In addition, the stretching, after stretching the casting film in the longitudinal direction, stretching in the width direction, or, after stretching in the width direction, successively biaxial stretching method of stretching in the longitudinal direction, or the longitudinal and width directions of the film And a uniaxial stretching method in which stretching is performed only in the longitudinal direction or the width direction. Here, the longitudinal direction refers to the running direction of the film, and the width direction refers to a direction parallel to the film surface and orthogonal to the longitudinal direction. The stretching may be performed in one step or in multiple steps as long as the effects of the present invention are not impaired.

  Further, the film may be subjected to a heat treatment after the stretching. The heat treatment can be performed by any conventionally known method such as in an oven or on a heated roll. This heat treatment is preferably performed at a temperature equal to or higher than the stretching temperature and equal to or lower than the stretching temperature + 50 ° C. The heat treatment temperature here means the highest temperature among the heat treatment temperatures performed after stretching. Further, the heat treatment time can be arbitrarily set within a range that does not deteriorate the characteristics.

  The heat-set film is cooled and then wound up as an intermediate product roll. Further, the film can be unwound from the intermediate product roll and cut in parallel with the longitudinal direction so as to have a desired width to obtain a wound final product roll. Note that the number of final product rolls obtained from one intermediate product roll may be one or more.

  In the film of the present invention, the stretching characteristics at room temperature and the dimensional change characteristics at high temperatures are controlled. Therefore, the film of the present invention has both flexibility and heat resistance, and can be suitably used as a substrate for a semiconductor manufacturing process.

  Hereinafter, the present invention will be described in detail with reference to examples. The characteristics were 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), it was measured at 25 ° C. and 65% RH using a film strength / elongation measuring apparatus (AMF / RTA-100) manufactured by Orientec Co., Ltd. First, a sample cut into a size of 150 mm in length and 10 mm in width in an arbitrary direction was stretched at an original length of 50 mm and a pulling speed of 300 mm / min, and a stress Ta (unit: MPa) at 5% elongation was determined. . The same measurement was performed five times for each sample, and the average value was calculated. Further, the measurement was performed in the same manner while changing the direction clockwise by 5 °, and the maximum value in each direction from 0 ° to 175 ° was defined as the stress at 5% elongation at 25 ° C (Ta (MPa)).

(2) 90 ° C. dimensional change rate 1 (Tx1, Ty1)
First, a film sample cut into a size of 15 mm (measurement direction) × 4 mm (a direction perpendicular to the measurement direction) in a room temperature environment was allowed to stand for 24 hours in an atmosphere at a temperature of 25 ° C. and a relative humidity of 65%. The length (L ₀ ) in the measurement direction was measured. Next, the film sample was heated from 25 ° C. to 160 ° C. at a load of 120 g / mm ² at a 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 , a 90 ° C. dimensional change rate 1 of the film sample was determined by the following equation 5.
Formula 5: 90 ° C. dimensional change rate 1 (%) = (L ₁ −L ₀ ) × 100 / L ₀ .

  The measurement direction was arbitrarily selected, five measurements were performed in the selected measurement direction, and the average value of the obtained measured values was set to a 90 ° C. dimensional change rate (%) in the direction. Further, the same measurement was performed by rotating the measurement direction clockwise by 5 °, 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 maximum value of the obtained values was defined as Tx1 (%), and the direction in which Tx1 (%) was obtained was defined as the X direction. Further, the direction orthogonal to the X direction in the plane was defined as the Y direction, and the dimensional change rate Ty1 (%) in the Y direction was determined from the value obtained by the previous measurement.

(3) 90 ° C. dimensional change rate 2 (Tx2)
The measurement was performed in the same manner as described in (2) except that the load at the time of measurement was 5 g / mm ² and the measurement direction was the X direction, and the obtained value was Tx2 (%). Note that the X direction here is the same as the X direction specified in (2).

(4) Plane Orientation Coefficient The refractive index in each direction of the film was measured using an Abago refractometer 4T manufactured by Atago Co., Ltd. equipped with a polarizer, and the plane orientation coefficient was determined by the following equation. The light source was a halogen lamp, the upper prism had a refractive index of 1.740, and the immersion liquid was methylene iodide (refractive index: 1.740). In addition, the measurement was performed on both surfaces of the film in a 23 ° C., 65 RH% environment for 24 hours using a temperature- and humidity-controlled sample under the environment. First, α is an arbitrary direction parallel to the film surface, β is a direction perpendicular to the film surface, and γ is a direction perpendicular to α and β (thickness direction), and the refractive index (nα) in each direction is α. , Nβ, nγ) were measured with an Abbe refractometer. Using the obtained values, the plane orientation coefficient (fn ₀ ) when the two directions on the film surface were α and β was determined by the following equation 6.
Equation 6: fn ₀ = (nα + nβ) / 2−nγ.

Then, γ is fixed and α and β are rotated clockwise by 5 ° while maintaining the parallelism with the film surface, respectively, to obtain nα5 and nβ5, and the refractive index (nα5, nβ5, nγ) in each direction is Abbe. The surface orientation coefficient (fn ₅ ) when the two directions on the film surface were α5 and β5 was determined by measuring with a refractometer and substituting nα5 for nα and nβ5 for nβ in Equation 6 above. Hereinafter, the same measurement was repeated until the two directions on the film surface became α85 and β85. The average value of the 18 measured values from fn ₀ to fn ₈₅ was defined as the plane orientation coefficient (fn).

(5) Glass transition temperature of each layer According to JIS K7121 (2012) using a differential calorimetric analysis (DSC), the sample was held at -120 ° C for 5 minutes in a nitrogen atmosphere, and the sample was measured at a rate of 20 ° C / min up to 250 ° C. The temperature was raised, and calculated from the measurement results by the following equation (7).
Equation 7: Glass transition temperature = (Extrapolated glass transition start temperature + Extrapolated glass transition end temperature) / 2
Equipment: Robot DSC-RDC220 manufactured by Seiko Electronic Industry Co., Ltd.
Data analysis system: Disk session SSC / 5200
Sample mass: 5mg
When the film has a laminated structure, first, a cross section in the thickness direction of the film cut out using a microtome is measured under a condition of an acceleration voltage of 75 kV using a transmission electron microscope H-7100FA (manufactured by Hitachi, Ltd.). An image was taken at a magnification of 40,000 times, and the layer configuration was specified and the thickness of each layer was measured. In some cases, a known staining method using RuO ₄ , OsO _4, or the like was used to increase the contrast of each layer. From the obtained values of the thickness of each layer, a sample at a depth corresponding to each layer was collected, and the glass transition temperature of each layer was measured by the above method.

  When a plurality of glass transition temperatures were confirmed as a result of the measurement, a value obtained by the following method was adopted as the glass transition temperature of the layer. First, the glass transition temperature of the film was measured by the above method, and the measured values were defined as Tg1, Tg2,. Next, in accordance with JIS K7244 (1999), tan δ for each temperature of the film is obtained using a dynamic viscoelasticity measuring device “DMS6100” manufactured by Seiko Instruments Inc., and Tg1, Tg2,. Corresponded to. When the value corresponding to each layer among Tg1, Tg2,... Tgn was separated, the temperature at which the value of tan δ was the largest was adopted as the glass transition temperature of the layer. The measurement conditions of the dynamic viscoelasticity measurement were a tensile mode, a driving frequency of 1 Hz, a distance between chucks of 5 mm, and a temperature rising rate of 2 ° C./min.

(6) Specification of Layer Configuration From the glass transition temperature of each layer of the film measured in (5), the layer A and the other layers (described as layer B) were specified.

(7) Coefficient of Static Friction Using a Toray-type slip tester 200G-15C (manufactured by MAKINO SEISAKUSHO), according to JIS K7125 (1999), two films are contacted so that one surface and the opposite surface are in contact with each other. The value at the time of arrangement and friction was measured three times, and the average value was defined as the static friction coefficient.

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

Measuring device: 3D fine shape measuring instrument (Model ET-4000A), manufactured by Kosaka Laboratory Co., Ltd. Analytical equipment: 3D surface roughness analysis system (Model TDA-31)
Stylus: tip radius 0.5 μmR, diameter 2 μm, diamond needle pressure: 100 μN
Measurement direction: Film longitudinal direction, film width direction once each (calculate the average value of both after measurement)
X measurement length: 1.0mm
X feed speed: 0.1 mm / s (measuring speed)
Y feed pitch: 5 μm (measurement interval)
Number of Y lines: 81 (number of measurement lines)
Z magnification: 20 times (vertical magnification)
Low frequency cutoff: 0.20mm (undulation cutoff value)
High frequency cutoff: R + Wmm (roughness cutoff value), R + W means no cutoff.

Filter method: Gaussian space type Leveling: Yes (tilt correction)
Reference area: 1 mm ² .

(9) Heat shrinkage stress of 90 ° C. A film of 15 mm (measurement direction) × 4 mm (direction orthogonal to the measurement direction), which was allowed to stand at a temperature of 25 ° C. and a relative humidity of 65% for 24 hours, was subjected to TMA / SS6000 (Seiko Instruments). The temperature was raised from 25 ° C. to 160 ° C. at a rate of 10 ° C./min in the L-assembly control mode, 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 were the X direction and the Y direction specified in (2).

(10) Shrinkage when heated at 80 ° C. for 1 hour The film was heated at 80 ° C. for 1 hour, and calculated from the dimensions before heating and the dimensions after heating according to the following equation 8. In addition, each dimension was measured by the method prescribed | regulated to JISK7133 (1999).
Equation 8: Shrinkage (%) = (dimension before heating−dimension after heating) / dimension before heating × 100.

(11) Stress Tb at 5% elongation at 25 ° C. after heating at 90 ° C. for 10 minutes
The stress at 5% elongation at 25 ° C. was measured in the same manner as in (1), except that a measurement sample that had been allowed to stand in an oven set to 90 ° C. in advance for 10 minutes was used, and the obtained value was defined as Tb.

(12) Ratio of maximum stress Ka at 50% elongation at 25 ° C. to stress Kb at 50% elongation Tensile test was performed on the film by the method described in (1) to obtain a stress at 50% elongation. Then, the maximum stress at the time of elongation by 50% from the maximum value of the stress value in the region of elongation of 50% or less of the stress-strain curve obtained by the measurement was read. The same measurement was performed five times using samples in the same measurement direction, and the average value was calculated for each of the stress at 50% elongation and the maximum stress at 50% elongation. The ratio (Kb / Ka) of Ka and Kb in the direction was calculated as the maximum stress Ka at the time of% elongation and the stress Kb at the time of 50% elongation. Further, the same measurement is repeated while changing the measurement direction clockwise by 5 °, and the ratio of Ka and Kb in each direction from 0 ° (initial measurement direction) to 175 ° is calculated, and the average value in all directions is calculated. Adopted.

(13) Number of adhered foreign substances having a diameter of 100 μm or more A 1 m (width direction) × 10 m (longitudinal direction) film is cut out at the center of the roll sample in the width direction to form a sample, and reflected light from a three-wavelength fluorescent lamp is used in a dark room. And a visual inspection was performed. When a foreign substance was observed, the foreign substance was observed with an electron microscope (LEICA DMLM, manufactured by Leica Microsystems, Inc.) at a magnification of 100 times, and the length of the major axis of the foreign substance was measured by the length measuring function of the microscope. The number of foreign substances having a long diameter of 100 μm or more was defined as C, and the number of adhered foreign substances having a diameter of 100 μm or more (number / m ² ) was calculated by the following equation (9). In addition, when the size of the film was less than the above dimensions, a visual inspection was performed using the entire film as a sample.
Formula 9: Number of attached foreign substances having a diameter of 100 μm or more (pieces / m ² ) = C (pieces) / 10 (m ² ).

(14) Unevenness in thickness Ten films of 10 cm × 10 cm were cut out from the center part in the width direction and both ends of the roll sample to obtain a sample for evaluation. For each sample, the thickness was measured at 5 points in the longitudinal direction, 5 points in the width direction, and a total of 10 points, and the thickness unevenness was obtained from the average value, the maximum value, and the minimum value according to the following expression 10.
Formula 10: Thickness unevenness (%) = (maximum thickness−minimum thickness) / average thickness Thickness unevenness of each of the obtained three samples in the width direction at three points (both ends and center) is calculated as follows. The average value was calculated and adopted as thickness unevenness. When the film was a sheet sample, 30 sheets of 10 cm × 10 cm were cut out at an arbitrary position on the sheet, and the average value of the thickness unevenness of each sample was calculated and adopted as the thickness unevenness.

(15) Uniform stretchability Nine straight lines are drawn on a 300 mm x 300 mm square film cut at random at intervals of 30 mm in parallel with one set of sides, and 9 straight lines are drawn at intervals of 30 mm in parallel with another set of sides. Was drawn as a measurement sample. Using a simultaneous biaxial stretching device, the obtained measurement sample is stretched under the following conditions in a direction parallel to one set of sides and in a direction parallel to the other set of sides, and based on the following criteria from the interval between straight lines. evaluated. In addition, the distance of the straight line measured the 6 intervals (a total of 12 intervals in 2 directions) formed by seven straight lines except the two straight lines at both ends in each direction, and was the most distant from 39 mm. Values were taken as measurements. The uniform stretchability was evaluated as B or more.

<Stretching conditions>
Stretching equipment: KARO IV lab stretcher manufactured by BRUCKNER Stretching temperature: 25 ° C
Stretching speed: 10 mm / min. Stretching ratio: 1.30 times.

<Evaluation criteria>
S: The linear interval in the stretched film was 39 ± 1 mm.
A: Not applicable to S, and the distance between straight lines in the stretched film was 39 ± 3 mm.
B: Not applicable to S and A, and the linear interval in the stretched film was 39 ± 6 mm.
C: Not applicable to any of S, A, and B.

(16) Uniform stretchability after heating A 300 mm x 300 mm square film that was arbitrarily cut out was heat-treated at 90 ° C for 10 minutes, and then similarly evaluated by the method described in (15).

(17) Dimensional stability at 90 ° C (heat resistance)
A 200 mm × 200 mm square film cut out arbitrarily was used as double-sided tape No. No. manufactured by Nitto Denko Corporation. It was attached to a stainless steel metal frame (outside: 200 mm × 200 mm, inside: 180 mm × 180 mm) at 500 AB to obtain a measurement sample. Next, the measurement sample was allowed to stand on a hot plate heated to 90 ° C. so that the film attached to the metal frame was in contact with the heated surface, and the amount of lifting with respect to the reference plane when left for 240 minutes was measured. From the obtained results, the dimensional stability was evaluated based on the following criteria. In the measurement of the lifting amount, the reference plane was set as the heated surface of the hot plate. The measurement was performed by changing the thickness of the metal frame used to 1 mm, 2 mm, and 3 mm. When the sample was observed from a horizontal position, the thickness of the metal frame where the deformed film could not be confirmed was adopted. When the film was confirmed even in the frame, it was evaluated as C. As for the dimensional stability, B or more was regarded as acceptable.
S: The lifting of the film was 1 mm or less.
A: Not applicable to S, and the lifting of the film was 2 mm or less.
B: Not applicable to S and A, and the lifting of the film was 3 mm or less.
C: Not applicable to any of S, A, and B.

(18) Dimensional stability at 120 ° C (heat resistance)
The heat resistance was evaluated in the same manner as in (17) except that the temperature of the hot plate was set to 120 ° C.

(19) Quality A total of 30 film samples of 200 mm × 200 mm each were cut out from the center position in the width direction of the sample collected in (13) and both end positions in the width direction. All samples were observed with an optical microscope at 100 magnifications for 10 fields of view, and the presence or absence of scratches having a length of 1 μm or more was confirmed. The value obtained by rounding off the first decimal place of the average value of the number of visual fields in which flaws of 1 μm or more were observed in each sample was defined as the number of visual fields in which flaws of 1 μm or more were observed. Based on the number of adhered foreign substances having a diameter of 100 μm or more measured in (13) and the number of visual fields in which flaws having a length of 1 μm or more were observed, the quality was evaluated according to the following criteria. In addition, when the number of visual fields in which flaws having a length of 1 μm or more were observed and the number of attached foreign substances having a diameter of 100 μm or more were evaluated differently (for example, the former was A and the latter was B), the worse one was used. (B) was adopted.
S: The number of visual fields where flaws having a length of 1 μm or more were observed was 0, and the number of adhered foreign substances having a diameter of 100 μm or more was more than 0 and 5 or less.
A: The number of visual fields where flaws having a length of 1 μm or more were observed was 1. Alternatively, the number of adhered foreign substances having a diameter of 100 μm or more exceeded 5 and was 8 or less.
B: The number of visual fields where flaws having a length of 1 μm or more were observed was 2-3. Alternatively, the number of adhered foreign substances having a diameter of 100 μm or more exceeded 8 and was 10 or less.
C: The number of visual fields where flaws having a length of 1 μm or more were observed was 4 or more. And / or the number of attached foreign substances having a diameter of 100 μm or more was more than 10.

(20) Adhesion A solution of an adhesive layer composition (adhesive: acrylic ester manufactured by Nippon Carbide Industry Co., Ltd.) was arbitrarily cut on a 200 mm × 200 mm square film surface so as to have a thickness of about 10 μm by a wire bar coating method. Resin-based solvent-type pressure-sensitive adhesive "Nissetsu" (registered trademark) "KP-2369" 100 parts by mass / crosslinking agent "CK-131" 2 parts by mass) is applied, and then a hot air oven HIGH manufactured by Espec Corporation. -It dried at 100 degreeC by TEMP-OVEN PHH-200 for 1 minute, and left still at room temperature 25 degreeC atmosphere of 65% of relative humidity for 3 days. The sample thus obtained was cut into a size of 150 mm × 30 mm, and a speed of 300 mm / min at room temperature and 25 ° C. using a film strength / elongation measuring device (AMF / RTA-100) manufactured by Orientec Co., Ltd. For 50%. Thereafter, an acrylic pressure-sensitive adhesive tape (Nitto 31B, manufactured by Nitto Denko Corporation) was adhered to the surface of the pressure-sensitive adhesive with a rubber roll, pressed with a 5 kg pressure roller, left standing for 24 hours, cut out to a width of 10 mm, and cut with a sample for evaluation. The end portion of the acrylic pressure-sensitive adhesive tape of the evaluation sample was folded at 180 °, the peel strength was measured with a tensile tester, and evaluated according to the following criteria.
S: Peel strength is 10 N / 25 mm or more.
A: Peel strength is 8 N / 25 mm or more and less than 10 N / 25 mm.
B: Peel strength is 6 N / 25 mm or more and less than 8 N / 25 mm.
C: Peel strength is less than 6 N / 25 mm.

(resin)
The resins used in the production of the film are as follows.

(Polyester A)
Polymerization was carried out from terephthalic acid and ethylene glycol using antimony trioxide as a catalyst by a conventional method to obtain a polyester A having an intrinsic viscosity of 0.65.

(Polyester B)
A polyethylene terephthalate particle master having an intrinsic viscosity of 0.65 and containing an aggregated silica particle having a volume average particle diameter of 4.5 μm at a particle concentration of 10% by mass in polyester A.

(Polyester C)
PBT-polyether copolymer “Hytrel” (registered trademark) 5557 manufactured by Toray-Dupont
(Polyester D)
Polybutylene terephthalate with an intrinsic viscosity of 0.8 (Polyester E)
PBT-polyether copolymer "Hytrel" (registered trademark) 3001 manufactured by Toray-Dupont
(Polyolefin A)
Crystalline polypropylene Prime Polymer Co., Ltd., TF850H
(Polyolefin B)
Ethylene-octene-1 copolymer “Engage” (registered trademark) EG8200 manufactured by Dupont Dow
(Polyolefin C)
Hydrogenated styrene-butadiene copolymer (HSBR) "DYNARON" (registered trademark) 1320P manufactured by JSR.

(Example 1)
A raw material for obtaining the layer A adjusted to the composition shown in Table 1 was supplied to a twin-screw extruder having an oxygen concentration of 0.2% by volume. The raw material for obtaining the layer A is melted by setting the cylinder temperature of the twin-screw extruder to 270 ° C., and then sent to a T-die through a short tube and a die at a temperature of 270 ° C., and the temperature is controlled to 25 ° C. from the T-die. It was discharged in the form of a sheet on the cooled cooling drum. At that time, a casting film was obtained by applying static electricity using a wire-like electrode having a diameter of 0.1 mm and closely contacting the cooling drum. Then, the film is stretched at a preheating temperature of 80 ° C. and a stretching temperature of 90 ° C. at a magnification of 1.44 times in both the longitudinal direction and the width direction using a simultaneous biaxial stretching apparatus. A single-layer film having a thickness of 180 μm was obtained. 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, the extrusion temperature, and the stretching conditions were as shown in Tables 1 to 6. Tables 1 to 6 show the evaluation results of each characteristic. In Examples 18 and 19, since the A layer does not exist, the “raw material for obtaining the A layer” in the first embodiment is a “raw material for obtaining the B layer”.

(Example 15)
A casting film was obtained in the same manner as in Example 8. Then, in a simultaneous biaxial stretching apparatus, after stretching at a preheating temperature of 100 ° C. and a stretching temperature of 120 ° C. in both the longitudinal direction and the width direction at a magnification of 1.44 times, a heat treatment was performed for 10 seconds in a zone heated to 130 ° C. Before winding, dust was removed from both surfaces of the film using a dust remover to obtain a single-layer film having a total thickness of 180 μm. Table 3 shows the evaluation results of each characteristic.

(Example 16)
The film configuration was as 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 supplied to separate twin-screw extruders each having an oxygen concentration of 0.2% by volume. After setting the cylinder temperature of each extruder to 270 ° C and merging the raw materials, they are merged and sent to a T-die through a short tube and a die with the temperature set to 270 ° C, and the temperature is controlled from the T-die to 25 ° C on a cooling drum. Discharged in sheet form. After that, a laminated film having a total thickness of 180 μm was obtained in the same manner as in Example 1. Table 3 shows the evaluation results of each characteristic.

(Example 17)
The film configuration was as 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 supplied to separate twin-screw extruders each having an oxygen concentration of 0.2% by volume. The cylinder temperature of the extruder that supplied the raw material for obtaining the layer A and the cylinder temperature of the extruder that supplied the raw material for obtaining the layer B were both set to 260 ° C. After passing through a short tube and a base, the mixture was sent to a T-die, and discharged from the T-die into a sheet on a cooling drum whose temperature was controlled at 25 ° C. Thereafter, a laminated film having a total thickness of 180 μm was obtained in the same manner as in Example 1 except that the stretching temperature was as shown in Table 3. Table 3 shows the evaluation results of each characteristic.

(Examples 29 to 33)
A casting film was obtained in the same manner as in Example 1. Next, the film is stretched in the longitudinal direction at a preheating temperature of 80 ° C. and a stretching temperature of 90 ° C. at a magnification shown in Table 5 using a roll stretching machine. Then, dust on both surfaces of the film was removed with a dust remover to obtain a single-layer film having a total thickness of 180 μm. Table 5 shows the evaluation results of each characteristic.

(Example 35)
A casting film was obtained in the same manner as in Example 1. Next, the film is stretched in the longitudinal direction at a preheating temperature of 80 ° C. and a stretching temperature of 90 ° C. at a magnification shown in Table 5 using a roll stretching machine. And a monolayer film having a total thickness of 180 μm was obtained. Table 5 shows the evaluation results of each characteristic.

(Example 39)
A casting film was obtained in the same manner as in Example 1 except that the raw material composition for obtaining the layer A was as shown in Table 6. Then, the film is stretched by a simultaneous biaxial stretching machine at a preheating temperature of 100 ° C. and a stretching temperature of 120 ° C. in both the longitudinal direction and the width direction at a ratio of 1.44 times, and is held for 3 seconds. Then, dust on both surfaces of the film is removed by a dust remover. Thus, a single-layer film having a total thickness of 180 μm was obtained. Table 6 shows the evaluation results of each characteristic.

(Comparative Examples 1 to 5)
A monolayer film having a total thickness of 180 μm was obtained in the same manner as in Example 1 except that the film configuration, the extrusion temperature, and the stretching conditions were as shown in Table 7. Table 7 shows the evaluation results of each characteristic. Note that the stretching method “−” in Comparative Examples 2 and 5 means that stretching was not performed.

  The resin composition in the film configuration was calculated assuming that the entire resin component constituting each layer was 100% by mass. The D surface refers to the surface that was in contact with the cast drum during film formation, and the ND surface refers to the surface opposite to the D surface. The same applies to Tables 2 to 7.

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

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

Claims (16)

5% elongation stress Ta at 25 ° C. is 1.0 MPa or more and 20.0 MPa or less,
When a load of 120 g / mm ² was applied and the temperature was raised from 25 ° C. to 160 ° C. at a rate of 10 ° C./min at 90 ° C., the dimensional change at 90 ° C. was 90 ° C. When the maximum direction is the X direction, the direction orthogonal to the X direction in the film plane is the Y direction, and the 90 ° C. dimensional change rate in the X direction is Tx1 (%), Tx1 is -10.00% or more. A film, which is not more than 00%. When a load of 5 g / mm ² was applied and the temperature was raised from 25 ° C. to 160 ° C. at a rate of 10 ° C./min at 90 ° C., the dimensional change at 90 ° C. was 90 ° C. dimensional change 2, the 90 ° C. dimension in the X direction. The film according to claim 1, wherein Tx2 is -10.00% or more and 1.00% or less when a rate of change 2 is Tx2 (%).   The film according to claim 1, wherein at least one surface has a plane orientation coefficient of 0.0080 or more and 0.0800 or less.   The film according to any one of claims 1 to 3, wherein when the layer having a glass transition temperature of -40C or more and 40C or less is the A layer, the film has one or more A layers. The film according to any one of claims 1 to 4, wherein the Tx1 and Ty1 satisfy the following equation (1) when the 90 ° C dimensional change rate 1 in the Y direction is Ty1 (%).
Formula 1: 0.10 ≦ | Tx1-Ty1 | ≦ 3.00   The film according to any one of claims 1 to 5, wherein a static friction coefficient measured by overlapping different surfaces of the film is 0.10 or more and 0.80 or less. The film according to any one of claims 1 to 6, wherein at least one surface has a surface roughness SRa (μm) and a ten-point average roughness SRzjis (μm) satisfying the following expression (2).
Formula 2: 5.0 ≦ SRzjis / SRa ≦ 25.0 The film according to any one of claims 1 to 7, wherein a 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, wherein a shrinkage ratio when heated at 80 ° C for 1 hour is more than 1.00% and not more than 10.00%. The film according to any one of claims 1 to 9, wherein the Ta and the stress Tb at 5% elongation at 25 ° C after heating at 90 ° C for 10 minutes satisfy the following expression (3).
Formula 3: 0.85 ≦ Tb / Ta ≦ 1.30 The film according to any one of claims 1 to 10, wherein a maximum stress Ka at 50% elongation at 25 ° C and a stress Kb at 50% elongation satisfy the following formula 4.
Formula 4: 0.70 ≦ Kb / Ka ≦ 1.00   The film according to any one of claims 1 to 11, wherein a 90 ° C dimensional change rate 1 in all directions is −25.00% or more and 10.00% or less.   The film according to any one of claims 1 to 12, wherein a 90 ° C dimensional change rate 2 in all directions is −25.00% or more and 1.00% or less. The film according to any one of claims 1 to 13, wherein the number of adhered foreign substances having a diameter of 100 µm or more is 10 particles / m ² or less.   The film according to any one of claims 1 to 14, wherein the thickness unevenness is 10.0% or less. The method for producing a film according to any one of claims 1 to 15, comprising a step of stretching in at least one direction at a magnification of 1.04 to 2.00 times. Method.