JP2005336428A - Film for semiconductor manufacturing process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film for semiconductor manufacturing process, having toughness, chemical resistance, morphological stability and extensible property, stably keeping the shape at normal temperature, softened by heating, and capable of being easily peeled off from a semiconductor set on the film. <P>SOLUTION: The film for semiconductor manufacturing process has storage elastic moduli (E') of 1,500-10,000 MPa at 60°C, 10-1,000 MPa at 80°C and 1-350 MPa at 100°C, which moduli are measured at a frequency of 0.1 Hz. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a film for a semiconductor manufacturing process used as a semiconductor support in a manufacturing process of a semiconductor wafer or a semiconductor chip.

  In manufacturing a semiconductor chip, a semiconductor wafer on which a circuit pattern has been formed is polished to a thickness of 100 to 600 μm by a polishing process (back grinding process) or a chemical process, and then a process for cutting the semiconductor wafer into a semiconductor chip (dicing process) is performed. A technique of picking up chips by expanding the chip interval by expanding is often performed. In such a process, the semiconductor wafer needs to be stably supported. For this purpose, the semiconductor is attached to and supported by an adhesive sheet. Adhesive sheets are tough enough to withstand impact in the polishing process, chemical resistance in the chemical treatment process, shape stability to withstand impact in the dicing process, and easy to pick up semiconductor chips in the expanding and peeling processes It is desirable to have stretchability and flexibility.

  Currently, in such a process, a sheet made of polyvinyl chloride, polyethylene, and polypropylene is used, and these characteristics are relatively well satisfied. However, when a sheet made of these materials is used, there is a problem that the semiconductor chip is lost in the dicing process because of lack of toughness and shape stability. Polyvinyl chloride is not preferable from the viewpoint of environmental problems, and an alternative material is required. In recent years, for the purpose of cost reduction and the like, as semiconductor wafers are becoming larger and thinner, more severe characteristics are required for the aforementioned characteristics.

  In such a background, a method using a composite film of a urethane polymer and a vinyl polymer (Japanese Patent Application Laid-Open No. 2003-171475) is known. This method involves coating a resin solution on a polyester support, Since it is a method of creating a sheet by drying and peeling, there is a problem that the manufacturing cost is high.

  Further, although a dicing film (Japanese Patent Laid-Open No. 2003-92273) having at least one polyester resin layer having a glass transition temperature of 0 ° C. to 50 ° C. is known, it is inferior in toughness at room temperature and difficult to handle. The problem of becoming may occur.

JP 2003-171475 A JP 2003-92273 A JP 2003-142505 A Japanese Patent Laid-Open No. 10-284444 JP-A-10-214801

  The present invention solves such problems of the prior art, and particularly has a toughness, chemical resistance, shape stability and stretchability as a film used in a semiconductor manufacturing process, and maintains its shape stably at room temperature. An object of the present invention is to provide a film for a semiconductor manufacturing process, which becomes flexible by applying temperature and can easily peel the semiconductor material and the film placed on the film.

  That is, the present invention has a storage elastic modulus (E ′) at a frequency of 0.1 Hz of 1500 to 10,000 MPa at 60 ° C., 10 to 1000 MPa at 80 ° C., and 1 to 350 MPa at 100 ° C. It is a film.

  According to the present invention, particularly as a film used in a semiconductor manufacturing process, it has toughness, chemical resistance, shape stability and stretchability, and maintains its shape stably at room temperature and flexibly by applying temperature. The film for semiconductor manufacturing processes which can peel easily the semiconductor material and film which were mounted on the turn film can be provided.

Hereinafter, the present invention will be described in detail.
[Storage modulus]
The film for semiconductor manufacturing process of the present invention has a storage elastic modulus (E ′) at a frequency of 0.1 Hz of 1500 MPa to 10,000 MPa at 60 ° C., 10 MPa to 1000 MPa at 80 ° C., and 1 MPa to 350 MPa at 100 ° C. is required.

  When the storage elastic modulus (E ′) at 60 ° C. is within the range of the present invention, the film is tough at room temperature. If the pressure is less than 1500 MPa, the film has insufficient toughness at room temperature, causing problems such as chipping of the laminated semiconductor wafer during back grinding, and cannot be used as a support. If it exceeds 10,000 MPa, the film is too hard and the handleability is poor.

  When the storage elastic modulus (E ′) at 80 ° C. is within the range of the present invention, the film becomes soft when an appropriate temperature is applied, and the semiconductor can be easily peeled off. If it is less than 10 MPa, the film is too soft and unsuitable as a support. If it exceeds 1000 MPa, the film is too hard and the handleability is poor.

  When the storage elastic modulus (E ′) at 100 ° C. is within the range of the present invention, the stretchability and flexibility when heated are good, and the semiconductor wafer and the support tape can be easily peeled off. it can. If it is less than 1 MPa, the film is too soft and does not function as a support. When it exceeds 350 MPa, the stretchability and flexibility of the film are inferior, and problems such as chipping of the semiconductor occur when the semiconductor is peeled off. Further, for example, in the process of picking up semiconductor chips after the dicing process, it is difficult to take out the chips individually.

[Laminated film]
The above storage elastic modulus characteristics can be preferably achieved by a laminated film comprising a substantially non-oriented polyester layer and an oriented polyester layer provided on both sides in contact with this layer. In this invention, Preferably this laminated | multilayer film is used as a film for semiconductor manufacturing processes.

[Polyester layer of oriented structure]
The polyester constituting the polyester layer having an oriented structure is preferably a polyester having a melting point of 205 to 270 ° C., and is preferably a crystalline polyester capable of forming an oriented structure. As this polyester, the polyester described below can be used. That is, the polyester constituting the oriented polyester layer is preferably a polyester in which the main dicarboxylic acid units are terephthalic acid units or terephthalic acid and isophthalic acid units, and the main glycol units are ethylene glycol units. This polyester may be, for example, 2,6-naphthalenedicarboxylic acid, orthophthalic acid, 2,7-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, 2,2- It may contain other carboxylic acid units such as biphenyldicarboxylic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, and for example, propylene glycol, 1,4-butanediol, 1,5-pentanediol, It may contain other glycol units such as 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, polyethylene glycol, polytetramethylene glycol.

  Specific examples of this polyester include polyethylene terephthalate, polyethylene terephthalate copolymerized with a small amount of the third component, polyethylene-2,6-naphthalate, polyethylene-2,6-naphthalate copolymerized with a small amount of the third component, and the like. it can.

  From the viewpoint of dimensional stability, deformation resistance and curl resistance of the film and its processed product, the glass transition temperature of the polyester constituting the polyester layer of the oriented structure is preferably 60 ° C. or higher, more preferably 70 ° C. or higher. is there.

[Non-oriented polyester layer]
The polyester constituting the non-orientated polyester layer is a polyester capable of forming an oriented structure (crystal structure) of the polymer by stretching treatment, and preferably has a melting point lower than the melting point of the polyester of the oriented structure polyester layer, preferably Uses a polyester having a melting point lower by at least 15 ° C., more preferably a melting point lower by at least 20 ° C., particularly preferably a melting point lower by at least 30 ° C., and a melting point of 190 ° C. or higher. Specifically, polyester having a melting point of 190 to 250 ° C. is preferably used.

  The polyester is preferably a copolyester in which the main dicarboxylic acid unit is terephthalic acid and / or 2,6-naphthalenedicarboxylic acid and / or isophthalic acid unit. Examples of the dicarboxylic acid unit to which this copolyester follows are those exemplified as other dicarboxylic acid units of the polyester constituting the polyester layer of the oriented structure, and glycol units of the polyester constituting the non-oriented polyester layer as the glycol unit. What was illustrated as can be mentioned preferably.

  Specific examples of this copolyester include 1) a copolyester composed of a dicarboxylic acid unit mainly composed of terephthalic acid units and naphthalenedicarboxylic acid units and a glycol unit mainly composed of ethylene glycol units, and 2) a terephthalic acid unit and an isophthalic acid unit. A copolyester composed of a dicarboxylic acid unit mainly composed of an ethylene glycol unit and a glycol unit composed mainly of an ethylene glycol unit, 3) a dicarboxylic acid unit mainly composed of a terephthalic acid unit, a naphthalenedicarboxylic acid unit and an isophthalic acid unit, and an ethylene glycol unit Preferred examples include copolyesters composed of glycol units. More preferable examples include a copolyester having a terephthalic acid unit of 90 to 60 mol%, a naphthalenedicarboxylic acid unit of 5 to 20 mol%, and an isophthalic acid unit of 5 to 20 mol% in the dicarboxylic acid unit.

  The glass transition temperature of the polyester constituting the polyester layer of the non-oriented structure is preferably 50 ° C. or higher so that the quality does not deteriorate even if the product is exposed to high temperatures during transportation and storage in the car in summer. More preferably, it has a glass transition temperature of 70 ° C. or higher, particularly preferably 80 ° C. or higher.

  In the present invention, the melting point of the polyester constituting the non-oriented polyester layer is 15 ° C. or more, more preferably 20 ° C. or more, particularly 30 ° C. or more lower than the melting point of the polyester constituting the oriented structure polyester layer. preferable.

  The difference between the glass transition temperature of the polyester constituting the non-oriented polyester layer and the glass transition temperature of the polyester constituting the oriented polyester layer is preferably 20 ° C. in order to improve film thickness unevenness. Hereinafter, it is more preferably 10 ° C. or less, particularly preferably 5 ° C. or less.

  In the present invention, the melting point refers to a melting endothermic peak temperature when a polyester, once melted, rapidly cooled and solidified, is heated at a rate of 20 ° C./min with a differential calorimeter.

  In the present invention, the glass transition temperature refers to a structural change (specific heat change) temperature when a polyester is once melted, rapidly cooled and solidified and then heated at a rate of 20 ° C./min with a differential calorimeter. .

[Additive]
The polyester constituting either the oriented polyester layer or the non-oriented polyester layer preferably contains a polyolefin resin. In this case, the polyolefin resin is preferably contained in an amount of 0.1 to 30% by weight per 100% by weight of the polyester layer. As the polyolefin resin, for example, polyethylene, polypropylene, or poly-4-methylpentene can be used.

  In order to impart an appropriate slipperiness and obtain a good handleability of the film, the polyester, particularly the polyester of the polyester layer having an oriented structure, preferably contains fine particles. The average particle diameter of the fine particles is preferably 2.5 μm or less. As fine particles, for example, inorganic fine particles such as silica, alumina, titanium oxide, calcium carbonate, and kaolin, precipitated fine particles of catalyst residue, for example, organic fine particles such as a crosslinked product of silicone, polystyrene, and acrylic can be used.

[Thickness]
The thickness of the film for a semiconductor production process of the present invention is preferably 25 to 300 μm, more preferably 50 to 250 μm, and particularly preferably 50 to 150 μm. When the film thickness is less than 25 μm, the film is weak and unpreferable as a support. When the film thickness is larger than 300 μm, the film is too stiff and inferior in handleability, and the absolute value (μm unit) of thickness spots is not preferable.

[Surface roughness]
In order to reduce the surface roughness of the semiconductor wafer to be supported in the film for semiconductor manufacturing process of the present invention, the surface roughness of the film for semiconductor manufacturing process is preferably 30 nm or less, and more preferably 20 nm or less.

[Thick spots]
The film for a semiconductor manufacturing process of the present invention has a thickness unevenness of preferably 10% or less, more preferably 5% or less, and particularly preferably 3% or less. In the semiconductor manufacturing process, the film is used as a support, and the thickness of the semiconductor wafer is adjusted while the films are bonded together. At that time, the thickness unevenness of the film is greatly related to the thickness unevenness of the semiconductor wafer. If the thickness unevenness exceeds 10%, the thickness unevenness of the stacked semiconductor wafers also increases in the semiconductor wafer manufacturing process, which is not preferable because the defect rate increases. In addition, problems such as chipping occur when the stacked semiconductor wafers are peeled off.

[Production method]
The polyester itself used in the present invention can be produced by a known method. Specific examples include 1) a method of reacting one or more dicarboxylic acid ester-forming derivatives with one or more glycols in the reaction step of polyester production, and 2) two or more polyesters. Examples thereof include a method of melt-mixing and performing a transesterification reaction (redistribution reaction) using a single-screw or twin-screw extruder. In these steps, if necessary, particles, polyolefin, and other various additives may be contained in the polyester.

  The film for semiconductor manufacturing process of the present invention is typically a laminated film having a three-layer structure. This film has an oriented structure polyester on both sides of a polyester layer (hereinafter sometimes referred to as “polyester B”) constituting a non-oriented polyester layer. A layer (hereinafter sometimes referred to as “polyester A”) of a polyester that constitutes the layer is further laminated and stretched by coextrusion to obtain a laminated film. And this laminated film is manufactured by performing the heat processing which is set to the temperature higher than the melting point of the polyester B and lower than the melting point of the polyester A. By this heat treatment, the polyester B of the core layer becomes a molten state, the oriented structure of the polyester of the core layer becomes a substantially non-oriented structure, and a non-oriented polyester layer is formed.

  This heat treatment can be preferably performed by performing the heat setting treatment after the stretching treatment in the coextrusion film forming method at a temperature higher than the melting point of the polyester of the polyester B and lower than the melting point of the polyester of the polyester A.

  In the present invention, the laminated film typically comprises a surface layer of polyester A and a core layer of polyester B. Specific configurations include a three-layer configuration of A / B / A (where / indicates the configuration of layers) type, a five-layer configuration of A / B / A / B / A type, and 7 according to these orders. Multi-layer configurations such as a layer, 9 layers, 2n + 1 (n is a natural number) configuration, and the like can be given. Further, if necessary, when two or more layers of polyester A are used, one or more layers can be composed of different polymers. The same applies when there are two or more layers of polyester B. For example, when the polyester A layer is composed of two types of polymers (A1, A2) and the polyester B layer is composed of two types of polymers (B1, B2), a three-layer configuration of A1 / B1 / A2 type, A1 / B1 / A 5-layer structure of A2 / B2 / A1 type can be exemplified. Of these layer configurations, 3 layers and 5 layers are preferable, and 3 layers are particularly preferable.

  In the present invention, the laminated film requires that the layer of polyester A having an oriented structure formed by stretching uniaxially or more constitutes the outermost layer. When the layer of polyester B having a substantially non-oriented structure constitutes the outermost layer, there is a problem that the film tends to stick to various rolls in the process during film production.

  In addition, as long as the effect of the present invention is not impaired on one side or both sides of the outermost surface of the laminated film in the present invention, surface modification such as improved lubricity, improved adhesion, improved antistatic property, improved releasability, etc. Therefore, surface treatment such as coating treatment or corona discharge treatment may be performed.

  As a surface treatment method such as a coating treatment, a polyester coating agent, a urethane coating agent, an acrylic coating agent or the like is used alone or in combination, and is applied within a process in film production. The method of apply | coating with another process later is mentioned.

  In the present invention, the laminated film is preferably produced by a coextrusion film forming method. A specific example thereof will be described in the case of the three-layer film (A / B / A), for example. First, the polyester A chip is dried and melted. In parallel with this, the polyester B chip is dried and melted. Subsequently, these molten polymers are laminated in three layers inside the die. For example, the molten polymer is laminated in three layers inside the die provided with a feed block, and then cast on a cooling drum to form an unstretched laminated film. A multilayer stretched film having an oriented structure formed by stretching the film in one or more directions on the vertical axis and / or the horizontal axis to be stretched in one or more axes is obtained.

  The same applies to the case of five or more layers. The stretching treatment is performed under the condition that the layer of polyester A forms a desired orientation structure, for example, at a temperature (Tc) of Tg (glass transition temperature) -10 ° C. to Tg + 50 ° C. of the polyester constituting the layer of polyester A. 2.5 times or more, preferably 3 to 6 times, more preferably 3 to 4 times, and then at a temperature of Tg + 10 to Tg + 50 ° C., 2.5 times or more, preferably 3 to 6 times in the transverse direction. Stretching, more preferably 3 to 4 times, is preferable in terms of improving the thickness unevenness of the film.

  The laminated film obtained as described above is further subjected to heat treatment. It is important that the heat treatment temperature is higher than the melting point of the polyester B. By this heat treatment, the polyester B is melted and the stretched orientation structure formed by the uniaxial stretching treatment is substantially free. It changes to an orientation structure. The heat treatment temperature is preferably 5 ° C. or more higher than the melting point of polyester B and 10 ° C. or lower than the melting point of polyester A.

  In addition, the effect of a heat setting process reaches polyester A by this heat processing. As the heat treatment method, for example, a method of performing heat treatment in the process immediately after stretching during film production, or a method of performing heat treatment after winding the film into a roll after completion of film production can be used.

[Thickness ratio]
The film for a semiconductor manufacturing process of the present invention has a ratio (a / b) of the total thickness (a) of the polyester layer having a substantially non-oriented structure and the total thickness (b) of the polyester layer having an oriented structure, It is preferably 0.01 to 1, more preferably 0.03 to 0.67, and particularly preferably 0.05 to 0.43. For example, when the layer structure is composed of three layers of A1 (thickness: a1) / B (thickness: b) / A2 (thickness: a2), the total thickness ratio of layer A and layer B (a / b) That is, (a1 + a2) / (b) means 0.01 to 1, and the layer structure is A1 (thickness: a1) / B1 (thickness: b1) / A2 (thickness: a2) / B2 (thickness). : B2) / A3 (thickness: a3), the total thickness ratio (a / b) of layer A and layer B, that is, (a1 + a2 + a3) / (b1 + b2) is 0.01 to 1. means. If the total thickness ratio (a / b) is less than 0.01, the thickness of the outermost layer of the polyester A layer is small. Therefore, it is difficult to control the thickness during film production, and the polyester B layer is partially exposed on the surface layer. The problem that it is easy to produce is caused, and the dimensional stability of the film is insufficient, which is not preferable. If the total thickness ratio exceeds 1, the proportion of the polyester B layer that has a substantially amorphous structure is small. Therefore, when the film is subjected to deformation processing such as molding or embossing, the film is sandwiched between holding fixtures. In use, the processability and flexibility of the film are insufficient, which is not preferable.

Hereinafter, the present invention will be described in more detail with reference to examples. Various physical properties were evaluated by the following methods.
(1) Dynamic viscoelasticity Using a dynamic viscoelasticity measuring apparatus (RHEOVIBRON model DDV-01FP manufactured by Orientec Co., Ltd.), a sample was set and measured under the following condition settings.
Measurement mode: Temperature characteristics Tensile Sample dimensions: Between chucks = 30 mm, W = 3 mm
Static load: 10g
Measurement temperature: room temperature to 200 ° C
Temperature rising rate: 2 ° C / min Interval: 2 ° C
Excitation mode: Single waveform Constant displacement amplitude: 25 μm
Minimum load amplitude: 0g
Measurement frequency 0.1Hz

(2) Thickness variation In a 20 cm × 20 cm sample, the film thickness was measured at 1 cm intervals in the vertical and horizontal directions with a dot-type thickness measuring instrument (manufactured by Anritsu Co., Ltd.), and a total of 400 data points were obtained. . Among the obtained data, the maximum thickness, the minimum thickness, and the average thickness were obtained, and the thickness unevenness was calculated by the following formula.
Thickness unevenness (%) = {(maximum thickness−minimum thickness) / (average thickness)} × 100

(3) Film thickness 100 points were measured with an external micrometer, and the average value was obtained as the film thickness.

(4) Thickness of each layer A sample was cut into a triangle, fixed in an embedded capsule, and then embedded in an epoxy resin. Then, the embedded sample was made into a thin film section having a thickness of 50 nm with a microtome (ULTRACUT-S) and then observed and photographed with a transmission electron microscope at an acceleration voltage of 100 kV. From these, the thickness of each layer was measured, and the average thickness and relative standard deviation were determined.

(5) Glass transition temperature / melting point About 10 mg of sample was sealed in an aluminum pan for measurement and mounted on a differential calorimeter (DuPont V4.OB2000 type DSC) at a rate of 25 ° C. to 20 ° C./min. The temperature was raised to 300 ° C., held at 300 ° C. for 5 minutes, then taken out, immediately transferred onto ice and rapidly cooled. The pan was again attached to the differential calorimeter, and the glass transition temperature (Tg) (unit: ° C) and melting point (Tm) (unit: ° C) were measured by increasing the temperature from 25 ° C to 20 ° C / min.

(6) Intrinsic viscosity Intrinsic viscosity (unit: [η] dl / g) was measured with an o-chlorophenol solution at 25 ° C.

(7) Preparation of polyester pellets Using dimethyl terephthalate and ethylene glycol as starting materials, and using manganese acetate, phosphoric acid and antimony trioxide as a catalyst, transesterification and polycondensation reactions were carried out in the usual manner. The polymer obtained was discharged from a reaction kettle and cooled to obtain polyethylene terephthalate pellets (hereinafter referred to as PET). The obtained PET had a glass transition temperature of 80 ° C., a melting point of 255 ° C., and an intrinsic viscosity of 0.65.
Transesterification and polycondensation in the same manner as PET except that 88 mol% dimethyl terephthalate (based on the total acid component) and 12 mol% dimethyl isophthalate (based on the total acid component) and ethylene glycol are used as starting materials. The reaction was carried out, and the resulting polymer was discharged from a reaction kettle and cooled to obtain copolymer polyethylene terephthalate pellets (hereinafter referred to as IA-CO-PET). The obtained IA-CO-PET had a glass transition temperature of 65 ° C., a melting point of 223 ° C., and an intrinsic viscosity of 0.69.
Esters are similar to PET except that 88 mol% dimethyl terephthalate (based on total acid components) and 12 mol% dimethyl 2,6-naphthalenedicarboxylate (based on total acid components) and ethylene glycol are used as starting materials. The exchange reaction and the polycondensation reaction were carried out, and the resulting polymer was discharged from the reaction kettle and cooled to obtain copolymerized polyethylene terephthalate pellets (hereinafter referred to as NDC-CO-PET). The obtained NDC-CO-PET had a glass transition temperature of 82 ° C, a melting point of 223 ° C, and an intrinsic viscosity of 0.69.
As a polybutylene terephthalate (hereinafter referred to as PBT) pellet, Duranex 500FP manufactured by Wintech Polymer Co., Ltd. was used.

[Example 1]
The mixture obtained by mixing the pellets of IA-CO-PET and PBT obtained above so as to be (IA-CO-PET) / (PBT) = 45/55 wt% was dried and melted with a single screw extruder. Then, it was melt-extruded from a die and cast on a cooling drum to obtain an unstretched film. Subsequently, the film was sequentially biaxially stretched 3.0 times at 100 ° C. in the longitudinal direction and 3.2 times at 100 ° C. in the transverse direction, and then heat-set at 195 ° C. to obtain a biaxially stretched film having a thickness of 75 μm. Obtained. The composition of the obtained film is shown in Table 1, and the characteristics are shown in Table 2.

[Example 2]
A biaxially stretched film was obtained in the same manner as in Example 1 except that the film thickness after biaxial stretching was 100 μm. The composition of the obtained film is shown in Table 1, and the characteristics are shown in Table 2.

[Example 3]
Mixture obtained by mixing PET and IA-CO-PET obtained above so that (PET) / (IA-CO-PET) = 42/58% by weight (after forming a film, it becomes a layer of polyester A) IA-CO-PET and NDC-CO-PET are mixed so that IA-CO-PET / NDC-CO-PET = 50/50% by weight (after forming into a film, a layer of polyester B) Were separately dried and melted with a single screw extruder, and then inside the die (mixture of PET and IA-CO-PET) | (IA-CO-PET and NDC-CO-PET mixture) | (PET and IA- The molten polymer was laminated on three layers of the CO-PET mixture), and cast on a cooling drum in this state to obtain an unstretched laminated film. Subsequently, the laminated film was successively biaxially stretched 3.0 times at 110 ° C. in the vertical direction and 3.2 times at 120 ° C. in the horizontal direction, and then heat-set at 235 ° C. to obtain a three-layer film. The thickness of this three-layer film is 75 μm in total, with 3.8 μm for each surface layer made of PET and IA-CO-PET and 67.4 μm for the core layer made of IA-CO-PET and NDC-CO-PET. there were. The structure of the obtained three-layer film is shown in Table 1, and the characteristics are shown in Table 2.

[Example 4]
Example of the thickness of the three-layer film, except that the surface layer on both sides composed of PET and IA-CO-PET is 5 μm each, and the core layer composed of IA-CO-PET and NDC-CO-PET is 90 μm, which is a total of 100 μm. Similar to 3, a three-layer film was obtained. The structure of the obtained three-layer film is shown in Table 1, and the characteristics are shown in Table 2.

[Example 5]
A three-layer film having a film thickness of 75 μm was obtained in the same manner as in Example 3 except that the stretching ratio was successively biaxially stretched 3.0 times in the longitudinal direction and 3.9 times in the transverse direction. The composition of the obtained three-layer film is shown in Table 1 and the characteristics are shown in Table 2. The film obtained in this example was a sample with particularly good thickness spots.

[Example 6]
A three-layer film having a film thickness of 75 μm was obtained in the same manner as in Example 3 except that the stretching ratio was successively biaxially stretched 3.6 times in the longitudinal direction and 3.9 times in the transverse direction. The composition of the obtained three-layer film is shown in Table 1 and the characteristics are shown in Table 2. The film obtained in this example was a sample with particularly good thickness spots.

[Example 7]
A three-layer film having a film thickness of 100 μm was obtained in the same manner as in Example 4 except that IA-CO-PET obtained above was used alone as the resin for forming the layer of polyester B. The structure of the obtained three-layer film is shown in Table 1, and the characteristics are shown in Table 2.

[Example 8]
A three-layer film having a film thickness of 100 μm was obtained in the same manner as in Example 4 except that NDC-CO-PET obtained above was used alone as a resin for forming the layer of polyester B. The structure of the obtained three-layer film is shown in Table 1, and the characteristics are shown in Table 2. The biaxially stretched films obtained in Examples 1 to 8 have favorable film thickness unevenness, and the storage elastic modulus E ′ at each temperature of 60 ° C., 80 ° C., and 100 ° C. is in an appropriate range. It was suitable as a film used for semiconductor manufacturing applications.

[Comparative Example 1]
The PET pellets obtained above were dried, melted with a single screw extruder, melt extruded from a die, and cast on a cooling drum to obtain an unstretched film. Subsequently, the film was successively biaxially stretched 3.0 times at 100 ° C. in the longitudinal direction and 3.2 times at 110 ° C. in the transverse direction, and then heat-set at 230 ° C. to obtain a 75 μm thick biaxially stretched film. Obtained. Table 1 shows the physical properties of the obtained film.

[Comparative Example 2]
The IA-CO-PET pellets obtained above were dried, melted with a single screw extruder, melt extruded from a die, and cast on a cooling drum to obtain an unstretched film. Subsequently, the film was successively biaxially stretched 3.0 times at 90 ° C. in the vertical direction and 3.2 times at 100 ° C. in the horizontal direction, and then heat-set at 230 ° C. to obtain a biaxially stretched film having a thickness of 75 μm. Obtained. Table 1 shows the physical properties of the obtained film.

[Comparative Example 3]
The mixture obtained by mixing the PET and PBT pellets obtained above so that PET / PBT = 40/60% by weight is dried, melted with a single screw extruder, melt-extruded from a die, and then on a cooling drum. To obtain an unstretched film. Subsequently, the film was successively biaxially stretched 3.0 times at 100 ° C. in the longitudinal direction and 3.2 times at 100 ° C. in the transverse direction, and then heat-set at 185 ° C. to obtain a 75 μm-thick biaxially stretched film. Obtained. Table 1 shows the physical properties of the obtained film.

  The biaxially stretched films obtained in Comparative Examples 1 to 3 have good film thickness unevenness, but the value of the storage elastic modulus E ′ at each temperature of 60 ° C., 80 ° C., and 100 ° C. is inappropriate. It was inappropriate as a film for semiconductor production.

  The film for a semiconductor production process of the present invention can be suitably used as a support in the production process of a semiconductor chip or a semiconductor wafer.

Claims (6)

  A film for a semiconductor manufacturing process having a storage elastic modulus (E ′) at a frequency of 0.1 Hz of 1500 to 10,000 MPa at 60 ° C., 10 to 1000 MPa at 80 ° C., and 1 to 350 MPa at 100 ° C.   The film for a semiconductor manufacturing process according to claim 1, comprising: a substantially non-oriented polyester layer; and an oriented polyester layer provided on both sides in contact with the layer.   The ratio (a / b) of the total thickness (a) of the substantially non-oriented polyester layer to the total thickness (b) of the oriented polyester layer is 0.01 to 1. The film for semiconductor manufacturing processes as described.   The film for a semiconductor manufacturing process according to claim 1, wherein the thickness unevenness of the film is 10% or less.   The film for a semiconductor manufacturing process according to claim 1, wherein the film has a thickness of 25 to 300 μm.   The film for semiconductor manufacturing processes which consists of the film for semiconductor manufacturing processes of Claim 1, and the adhesion layer provided on it.