Release film for semiconductor molds, method for manufacturing semiconductors, and semiconductors

Abstract

This invention provides a release film for semiconductor molds and a semiconductor manufacturing method that can suppress the occurrence of wrinkles during mold molding. [Solution] A release film for semiconductor molding comprising a base layer and a release layer, wherein the dimensional change rate S(150)( / °C) of the film at 150°C, measured by thermomechanical analysis (TMA) in the longitudinal and width directions, satisfies formula (I). -0.030≦S(150)≦0.030 (I)

Description

[Technical Field]

[0001] The present invention relates to a release film used in the processing steps of semiconductor mold packaging, and is particularly suitable for use as a mold release film in the semiconductor encapsulation process. [Background technology]

[0002] Semiconductor chips are sealed in resin to protect them from external disturbances such as light, heat, moisture, and physical shock, and are mounted on a substrate as a molded product called a package. Curable resins such as epoxy resin are used to seal semiconductor chips. As for methods of sealing semiconductor chips, the so-called transfer molding (resin flow molding) method and compression molding (compression molding) method are known, but in recent years, the introduction of the compression molding method has been progressing against the backdrop of trends in shape such as the increase in the area of ​​semiconductor wafers, the thinning of packages, and the increase in the number of pins to accommodate more input terminals.

[0003] Compression molding is a process in which molten sealing resin is compressed and cured by the up-and-down movement of a heated mold. In this process, it is common practice to insert a release film to ensure release between the mold and the sealing resin. Ethylene-tetrafluoroethylene copolymer (ETFE) films have been widely used as release films because they have excellent release properties, heat resistance, and conformability to the mold shape. However, because they have high permeability to gases generated from the curing molding resin and tend to contaminate the mold, research is being conducted on materials with low gas permeability, mainly polyester (Patent Document 1).

[0004] In the case of release films using polyethylene terephthalate (PET) film as a base material, which has excellent dimensional stability among polyester films, it is necessary to provide a release layer in addition to the base film. Release films in which polyethylene terephthalate is used as the heat-resistant resin layer and polymethylpentene as the release layer, and these are laminated together, have been investigated (Patent Document 2).

[0005] In recent years, against the backdrop of technological trends such as the increase in the area of semiconductor wafers, the reduction in the height of packages, high integration, 3D stacking, and functional integration, the introduction of the compression molding method has been progressing. Fan-out wafer-level packaging (FO-WLP) technology, in which the package size is larger than the chip size, and panel-level packaging (PLP) technology, in which a large area is sealed with a larger mold, are expanding. Fig. 1 shows a schematic diagram of the face-down compression molding process for manufacturing FO-WLP. As a release film corresponding to these latest package technologies, a release film for compression molding with excellent designability and formability has been studied (Patent Document 3).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0007] In these packaging processes, wrinkles tend to occur in the release film during processing, and the generated wrinkles are transferred to the mold resin, which is cited as a factor reducing the yield. Therefore, in Patent Document 4, an attempt is made to suppress wrinkles by controlling the dimensional change rate of the film. However, with the described method, although wrinkles in one direction can be suppressed, wrinkles in the direction orthogonal to that direction cannot be suppressed.

[0008] Furthermore, although the polyester films with laminated release layers described in Patent Documents 5 and 6 use polyester as a base material, which has higher dimensional stability than ethylene-tetrafluoroethylene copolymer films, the aforementioned problem of wrinkles forming during heating was not improved.

[0009] Based on the above, the problem that the present invention aims to solve is to provide a release film for semiconductor molding and a semiconductor manufacturing method that can suppress the occurrence of wrinkles during mold molding. [Means for solving the problem]

[0010] To solve the above problems, a preferred embodiment of the present invention has the following configuration. 1. A release film for semiconductor molding comprising a base layer and a release layer, wherein the dimensional change rate S(150)( / °C) of the film at 150°C, measured by thermomechanical analysis (TMA) in the longitudinal and width directions, satisfies formula (I). -0.030≦S(150)≦0.030 (I) (Method for measuring S(150)) The film was cut into rectangular pieces measuring 50 mm in length and 4 mm in width in both the longitudinal and transverse directions to form samples. The dimensional changes were measured using a thermomechanical analyzer (Seiko Instruments, TMA EXSTAR6000) when the temperature was increased from 25°C to 170°C under the following conditions. Trial length: 20mm Load: 29.4mN Heating rate: 10°C / min Measurement temperature range: 25~170℃ Measurement interval: 2 seconds The dimensional change T(K)(%) during heating at a temperature K(°C) is calculated using the following formula based on the results measured during the above heating process. T(K) = [{Film length at temperature K during the heating process (mm) - Film length at 30°C during the heating process (mm)} / Film length at 30°C during the heating process (mm)] × 100 The dimensional change rate S(150)( / °C) at a temperature of 150°C is calculated using the following formula, where K1(°C) is the temperature when the temperature first exceeds 150°C during measurement, and K2(°C) is the temperature observed 2 seconds after K1. S(150)=(T(K2)-T(K1)) / (K2-K1) The measurements were taken five times each in the longitudinal and widthwise directions, changing the sampling position each time. The average value calculated from the obtained measurements was then adopted as the value for each direction. 2. A release film for semiconductor molding according to 1., comprising a base layer and a release layer, wherein the dimensional change rate S(150)( / °C) of the film at 150°C, measured by thermomechanical analysis (TMA) in the longitudinal and width directions, satisfies formula (I'').

[0011] -0.030≦S(150)≦0.010 (I'') 3. A release film for semiconductor molding according to 1. or 2., wherein the dimensional change T(150)(%) at 150°C, measured by thermomechanical analysis (TMA) in the longitudinal and width directions, satisfies formula (II). -1.5 ≦T(150) ≦ 1.5 (II) 4. A release film for semiconductor molding according to any of 1. to 3., wherein the dimensional change T'(30) (%) of the film at 30°C after cooling from 170°C to 25°C, as measured by thermomechanical analysis (TMA) in the longitudinal and width directions, satisfies the following (III). -1.0≦T'(30) ≦0.0···(III) (Method for measuring T'(30)) The film was cut into rectangular pieces measuring 50 mm in length and 4 mm in width in both the longitudinal and transverse directions to form samples. Using a thermomechanical analyzer (Seiko Instruments, TMA EXSTAR6000), the dimensional changes were measured when the temperature was increased from 25°C to 170°C and then decreased from 170°C to 25°C under the following conditions. Trial length: 20mm Load: 29.4mN Temperature rise / fall rate: 10°C / min Measurement temperature range: 25~170℃ Measurement interval: 2 seconds T'(30) = [{Film length at 30°C during the cooling process (mm) - Film length at 30°C during the heating process (mm)} / Film length at 30°C during the heating process (mm)] × 100 5. The bending stiffness F at 150°C is 1.0 mN·mm in both the longitudinal and widthwise directions. 2 The above is 20.0 mN·mm 2 A release film for semiconductor molding described in any of the following 1. to 4. 6. In the longitudinal and widthwise directions, the deflection parameter σ given by equation (IV) below is 0.50 mN. -1 ·mm -1 A release film for semiconductor molds, as described in any of the following 1. to 5. σ = T(150) / F···(IV) Note that T(150) is the dimensional change T(150)(%) at 150°C, measured by thermomechanical analysis (TMA), and F is the bending stiffness F at 150°C. 7. A release film for semiconductor molding according to any one of 1 to 6, comprising a base layer and a release layer, wherein the air release time on at least one side after heating and pressing by the following method is 10 seconds or more and 500 seconds or less. Heating and pressing method: Using a press machine with the release film heated to 125°C for both the upper and lower molds, a three-layer structure consisting of "SUS304 plate with a thickness of 0.5 mm and an arithmetic mean roughness Ra of 0.1 μm" / release film / "SUS304 plate with a thickness of 0.5 mm and an arithmetic mean roughness Ra of 0.1 μm" is placed between the upper and lower molds. The SUS304 plate used is hairline finished and has a maximum height Rz (JIS B0601-2001) of 2 μm or less. After a preheating time of 5 minutes, heating and pressing is performed for 10 minutes under conditions of 4.0 MPa. 8. A release film for semiconductor molding according to any one of 1 to 7, wherein the release layer contains a long-chain alkyl group-containing compound. 9. A release film for semiconductor molding described in any of 1. to 8., wherein the peel force measured under the following conditions is 0 mN / cm or more and 100 mN / cm or less. (Measurement method, conditions) A "Kapton" (registered trademark) film is placed on a steel plate, and a 1mm thick metal frame with a 5cm x 5cm square hole is placed on top. 5.0g of mold resin (Nagase ChemteX Co., Ltd.: product name "R4508") is placed in the cavity of the metal frame, and a sample of mold release film measuring 6cm x 10cm is placed on top with the release layer facing the resin. A "Kapton" (registered trademark) film and a steel plate are then placed on top to create a laminate. This laminate is placed in a heated vacuum press machine heated to 150°C and pressurized at a pressure of 3MPa while maintaining the temperature at 150°C for 10 minutes. After being left for 24 hours in an atmosphere at room temperature (23°C) and relative humidity (65%), the release force between the mold resin and the film is measured for N=5 using a peel test machine (Kyowa Interface Chemical Co., Ltd.: Adhesive / film peel analysis device VPA-2) at a peel angle of 90° and a peel speed of 50mm / min, and the average value is calculated to determine the peel force. 10. A release film for semiconductor molding according to any one of 1 to 8, comprising a base layer mainly composed of polyester resin and a release layer provided on the base layer, wherein the copolymer content of the base layer is 3 mol% or more and 12 mol% or less. A method for manufacturing semiconductors, comprising using a release film for semiconductor molding described in any of sections 11.1 to 10 in the process of covering a semiconductor element with a molding resin. 12. The semiconductor manufacturing method according to 11, wherein the sum of the center surface average roughness SRa of the surface of the release film for semiconductor molding that contacts the mold after heating and pressing, and the center surface average roughness SRa of the mold surface of the molding apparatus used, is 0.5 μm or more and 3.0 μm or less. Heating and pressing method: Using a press machine with the release film heated to 125°C for both the upper and lower molds, a three-layer structure consisting of "SUS304 plate with a thickness of 0.5 mm and an arithmetic mean roughness Ra of 0.1 μm" / release film / "SUS304 plate with a thickness of 0.5 mm and an arithmetic mean roughness Ra of 0.1 μm" is placed between the upper and lower molds. The SUS304 plate used is hairline finished and has a maximum height Rz (JIS B0601-2001) of 2 μm or less. After a preheating time of 5 minutes, heating and pressing is performed for 10 minutes under conditions of 4.0 MPa. 13. The method for manufacturing a semiconductor according to 11., wherein the mold resin contains inorganic particles and the maximum particle size of the inorganic particles is 1 μm or more and 80 μm or less. 14. In the step of covering with the mold resin, the area of the substrate covered by the mold resin is 650 cm 2 or more and 15000 cm 2 or less. The method for manufacturing a semiconductor according to 11. 15. A semiconductor molded with a mold resin, wherein the mold resin contains inorganic particles, the maximum particle size of the inorganic particles is 1 μm or more and 80 μm or less, the thickness of the mold resin is 0.1 mm or more and 2.5 mm or less, the element area of the semiconductor is 100 mm 2 or more and 250000 mm 2 or less, the semiconductor has a plurality of semiconductor elements integrated into one package via an interposer, and the color difference ΔC * measured by a colorimeter is 0.20 or less.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a release film for semiconductor molding that can suppress the generation of wrinkles during molding, and a semiconductor manufacturing method. By suitably using such a release film as a release film for molding in the semiconductor encapsulation process, the mass productivity of semiconductor chips can be improved.

Brief Description of the Drawings

[0013] [Figure 1] FIG. is a schematic cross-sectional view of a face-down compression molding process for manufacturing FO-WLP. [Figure 2] FIG. is a top view for explaining a method of measuring peel strength. [Figure 3] FIG. is a cross-sectional view for explaining a method of measuring peel strength.

Embodiments for Carrying Out the Invention

[0014] The release film for semiconductor molding in the present invention (hereinafter sometimes simply referred to as "release film") has a two-layer structure including a base layer and a release layer. The release layer referred to here is a layer located on at least one surface, and it is preferable that the water contact angle on that surface, as measured by the method described later, is 85° or more.

[0015] A preferred embodiment of the release film for semiconductor molding in the present invention is such that the dimensional change rate S(150)( / °C) of the film at 150°C, as measured by thermomechanical analysis (TMA) in the longitudinal and width directions, satisfies equation (I). -0.030≦S(150)≦0.030 (I) In this context, the longitudinal direction refers to the direction measured within the film plane by the method described later in (4) Young's modulus, and the width direction refers to the direction perpendicular to the longitudinal direction within the film plane.

[0016] When using a release film in the semiconductor molding process, the release film is brought into contact with a mold that has been heated from room temperature to a high temperature, and then vacuum-suctioned to conform to the mold shape. However, it has been found that in this process, the rapid temperature rise when the release film is adsorbed to the mold causes the release film to expand and wrinkle, and these wrinkles may be transferred to the package molded in the molding process. As a result of diligent research by the inventors, it has been found that by setting the dimensional change rate S(150) at 150°C in the longitudinal and width directions to a specific range shown in equation (I), it is possible to suppress the occurrence of wrinkles and obtain a package with a good appearance. Regarding equation (I), it is more preferable to satisfy equation (I') from the viewpoint of suppressing wrinkles, and even more preferable if equation (I'') is satisfied. -0.030≦S(150)≦0.020 (I') -0.030≦S(150)≦0.010 (I'') By keeping S(150) within the above range, the amount of dimensional change due to rapid temperature changes when the film comes into contact with a heated mold or molding resin is reduced, and as a result, it is possible to suppress the occurrence of wrinkles. The inventors believe that the reason for this is as follows: Wrinkles occur in the molding process because the expanded film folds and wrinkles form in the film. S(150) indicates the slope of the dimensional change at 150°C, and the larger this value, the higher the expansion rate with temperature changes. Therefore, if S(150) is larger than the range of equation (I), the dimensions change rapidly due to the rapid temperature change when the film comes into contact with the mold, making it easier for wrinkles to occur. In addition, a large amount of dimensional change at 150°C (T(150)) is also a factor that makes it easier for wrinkles to occur, as will be explained later. However, since the film is constantly adsorbed by vacuum in the mold, even if T(150) is large, if S(150) is small and the change in dimensional change due to temperature changes is gradual, adsorption to the mold will be dominant and wrinkles will not easily occur, so the influence of S(150) is large. Also, even if S(150) in one direction is controlled to be low, if S(150) in the other direction is not within the above range and expands, wrinkles will occur, so it is important that both the longitudinal and width directions satisfy equation (I).

[0017] Furthermore, by controlling the temperature within the range of (I), it is possible to suppress the occurrence of wrinkles even in molding processes where the mold temperature is up to 190°C. This is because, even when the mold temperature is around 190°C, the temperature of the mold surface exposed to the atmosphere is low, and the temperature of the film in contact with it is also lower compared to the set temperature of the mold. Therefore, by effectively controlling the dimensional change rate S(150) at 150°C within the range of equation (I), it is possible to contribute to the suppression of wrinkles in processes up to a mold temperature of 190°C.

[0018] Furthermore, from the viewpoint of wrinkle suppression, a smaller S(150) is preferable. However, if S(150) falls below -0.030, rapid shrinkage of the film during heating can cause unevenness in the film thickness, resulting in unevenness on the surface of the molded product and an appearance defect. Therefore, it is preferable that S(150) be -0.030 or higher.

[0019] The method by which the release film of the present invention satisfies the above is not particularly limited, but for example, in the manufacturing process of the release film, S(150) can be controlled to be low by including a step in the last step (step Z) of all steps in which the film temperature is 50°C or higher, in which tension of 0.5 MPa to 5 MPa is applied in both the longitudinal and width directions, while holding the film at a temperature Tz in the temperature range of 50°C to 190°C. If the final step in the steps in the temperature range of 50°C to 190°C is in which tension is applied in only one direction, either the longitudinal or width direction, the film may shrink in the direction where no tension is applied, resulting in large expansion during heating in the molding step, causing one direction of the film to no longer satisfy (I), which may lead to the formation of wrinkles. Furthermore, it is more preferable to include a step Y immediately preceding step Z in which tension of 0.5 MPa to 5 MPa is applied in both the longitudinal and width directions at a temperature of Tz + 5°C to 195°C. By gradually decreasing the temperature while applying tension, rapid dimensional changes due to temperature changes can be suppressed. Furthermore, regarding the resin composition of the base layer, a higher crystallinity of the film is preferable. The higher the crystallinity, the less fluid it is even under high-temperature conditions, and the more expansion can be suppressed. From the viewpoint of suppressing crystallinity, it is preferable that the (8) cold crystallization heat ΔHc, described later, be 15 J / g or more, more preferably 20 J / g or more, and even more preferably 25 J / g or more.

[0020] This release film has a deflection parameter σ of 0.50 mN in both the longitudinal and width directions. -1 ·mm -1 The following is preferable. The deflection parameter σ referred to here is a value obtained from the bending stiffness F at 150°C and the dimensional change rate T(150) at 150°C, which is measured by thermomechanical analysis (TMA), as described later. The smaller σ is, the more effectively wrinkle formation can be suppressed.

[0021] The reason why a smaller deflection parameter σ makes wrinkles less likely is as follows: When wrinkles occur in a film, the areas that expand due to the heat of the mold bend, causing the film to fold and wrinkle. This deflection parameter σ represents the ease of bending; the larger the area that bends due to the expansion of the film, and the lower the bending stiffness of the film, the easier it is to fold, and the easier it becomes to bend. Based on the above, a deflection parameter σ of 0.50 mN is appropriate. -1 ·mm -1 The following is preferable: 0.30 mN -1 ·mm -1 The following is more preferable: 0.10 mN -1 ·mm -1 The following is even more preferable. The effect of controlling this deflection parameter σ is particularly significant in processes that seal large-area packages, such as PLP (Panel Level Package), which will be described later, as it helps to suppress wrinkles. This is because, in PLP, due to the large area of ​​the mold, when the film is drawn onto the mold by vacuum, the force of suction does not reach the center in particular, resulting in deflection and thus increased wrinkle formation. In other words, by controlling the deflection parameter σ, deflection can be suppressed, and the wrinkle suppression effect is greatly increased.

[0022] One method for controlling the deflection parameter σ to a low level is to appropriately control the dimensional change rate at 150°C and the bending stiffness F at 150°C.

[0023] From the viewpoint of suppressing the deflection parameter σ and preventing wrinkles, it is preferable that the dimensional change T(150)(%) at 150°C, measured by thermomechanical analysis (TMA) in the longitudinal and width directions, satisfies equation (II). -1.50 ≦T(150) ≦ 1.50 (II) While there are no limitations on the method of controlling within this range, for example, in the manufacturing process of a release film, when performing a relaxation treatment in a heating step where the film temperature reaches 50°C or higher, the amorphous structure of the film can be controlled by controlling S(150) to a low value and performing the relaxation treatment in two or more stages, thereby obtaining a film that falls within the above range. From the viewpoint of suppressing wrinkles, T(150) is preferably 1.50% or less, more preferably 1.00% or less, and most preferably 0.80% or less. On the other hand, if T(150) falls below -1.50%, rapid shrinkage of the film during heating causes unevenness in the film thickness, resulting in unevenness on the surface of the molded product and causing appearance defects. Therefore, T(150) is preferably -1.50% or higher.

[0024] Furthermore, from the viewpoint of controlling the deflection parameter σ to be low, the bending stiffness F at 150°C in both the longitudinal and width directions is set to 1.0 mN·mm 2 Preferably, the bending stiffness F at 150°C is 1.0 mN·mm. 2 By doing so, the deflection parameter σ can be controlled to be low, and the occurrence of wrinkles can be suppressed. In addition, the bending stiffness F is 1.0 mN·mm 2 By doing so, tearing of the film during molding can be suppressed. The bending stiffness F at 150°C is 2.0 mN·mm from the viewpoint of wrinkle suppression and handling. 2 The above is more preferable, 3mN·mm 2 The above is more preferable. On the other hand, from the viewpoint of improving mold conformability in the molding process and suppressing resin chipping during molding, the bending rigidity should be 15.0 mN·mm. 2 The following is preferable: 13.0 mN·mm 2 The following is more preferable: 10.0 mN·mm 2 The following is even more preferable: 8.0 mN·mm 2 The following are particularly preferable.

[0025] The method for controlling the bending stiffness at 150°C is not particularly limited, but it can be controlled by designing the film thickness and Young's modulus at 150°C. From the viewpoint of controlling the bending stiffness as described above, the film thickness is preferably 10 μm to 100 μm, and more preferably 20 μm to 70 μm. After controlling the film thickness within the above range, the bending stiffness F can be controlled to a preferred range by adjusting the Young's modulus of the film. In order to control the Young's modulus at 150°C to a high level, for example, it is preferable to use a polyester resin with a relatively high Young's modulus as the main component. Here, using polyester resin as the main component means that the polyester resin is contained in an amount greater than 70% by mass relative to the components constituting the base layer. By using polyester resin as the main component and orienting it biaxially, oriented crystallization is promoted, and the Young's modulus can be increased. In the present invention, it is preferable that the base layer is mainly composed of polyester resin.

[0026] As for the polyester resin, from the viewpoint of film-forming properties, it is preferable to use polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, or polylactic acid. Among these, polyethylene terephthalate or polyethylene-2,6-naphthalate is more preferable due to its ease of processing, and polyethylene terephthalate is particularly preferable from the viewpoint of design.

[0027] Furthermore, in order to keep the bending rigidity below the upper limit described above, it is preferable to add copolymer components to the polyester resin. Here, the copolymer components of the polyester resin refer to polymers composed of either or both dicarboxylic acid components and diol components that are different from the main constituent components that make up 50 mol% or more of the total polyester resin. When blending with homopolymers is considered, it is preferable to use a copolymer in which the same molecular structure as the target homopolymer makes up 50 mol% or more of the total. Here, as the copolymer components of the polyester resin, the dicarboxylic acid components include aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedionic acid, dimer acid, eicosanedionic acid, pimelic acid, azelaic acid, methylmalonic acid, and ethylmalonic acid; alicyclic dicarboxylic acids such as adamantanedicarboxylic acid, norbornenedicarboxylic acid, cyclohexanedicarboxylic acid, and decalindicarboxylic acid; terephthalic acid, isophthalic acid, phthalic acid, and 1,4-naphthalenedicarboxylate. Examples of diol components include aromatic dicarboxylic acids such as nic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylsulfondicarboxylic acid, 5-sodium sulfisophthalic acid, phenylendanedicarboxylic acid, anthracenedicarboxylic acid, phenantradiocarboxylic acid, 9,9'-bis(4-carboxyphenyl)fluorenic acid, or their ester derivatives. Representative examples of diol components include aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, and 1,3-butanediol; alicyclic diols such as cyclohexanedimethanol, spiroglycol, and isosorbide; and aromatic diols such as bisphenol A, 1,3-benzenedimethanol, 1,4-benzenedimethanol, and 9,9'-bis(4-hydroxyphenyl)fluorene.Among these, alicyclic dicarboxylic acids, isophthalic acid, and naphthalenedicarboxylic acid are particularly preferred from the viewpoint of excellent polymerization suitability, thermal stability, and compatibility with homopolymers. Diol components preferably include butanediol, ethylene glycol, spiroglycol, and cyclohexanedimethanol as copolymer components. These may be used individually or in combination as needed.

[0028] When the total amount of copolymer components in 100 mol% of dicarboxylic acid components is A mol%, and the total amount of copolymer components in 100 mol% of glycol components is B mol%, the amount of copolymer components calculated as A + B is preferably 12 mol% or less, and more preferably 10 mol% or less, from the viewpoint of controlling S(150) to a low level. On the other hand, from the viewpoint of improving moldability, the amount of copolymer components is preferably 3 mol% or more. In the case where the base layer has a laminated structure and the amount of copolymer components in each layer is different, the amount of copolymer components in the base layer is considered to be the sum of the products of the lamination ratio and the amount of copolymer components of each layer for all layers.

[0029] From the viewpoint of controlling the bending stiffness within the above range, it is preferable to control the crystallinity of the film, and from the viewpoint of suppressing crystallinity, it is preferable that the amount of heat of cold crystallization ΔHc, described later, be 15 J / g or more, more preferably 20 J / g or more, and most preferably 25 J / g or more.

[0030] By controlling T(150) and F within the above range, and further suppressing the deflection parameter σ within the above range, it is possible to significantly suppress the occurrence of wrinkles, especially on large screens such as PLPs.

[0031] From the viewpoint of further suppressing wrinkles, it is preferable that the dimensional change T'(30)(%) of the film at 30°C after cooling from 170°C to 25°C, as measured by thermomechanical analysis (TMA), in the longitudinal and width directions satisfies the following condition (III). -1.0≦T'(30) ≦0.0···(III).

[0032] T'(30) is the dimensional change when the film is heated to 170°C and then returned to room temperature. By controlling this value within this range, the occurrence of wrinkles can be reduced. The inventors estimate the reason for this as follows: A T'(30) of 0.0 or less indicates that even if the dimensional change is large during heating, the film tends to shrink as the temperature decreases. When the film comes into contact with the resin during the molding process after being adsorbed onto the mold, the temperature of the resin is lower than that of the mold, so it is presumed that the temperature of the film will drop slightly. In other words, in a film where T'(30) is controlled to 0.0 or less, the film shrinks, and some of the wrinkles that occurred during mold adsorption are eliminated, so the final number of wrinkles is thought to be reduced. Furthermore, controlling T'(30) to 0.0 or less is preferable because it prevents the film itself from bending due to poor dimensional change after the molding process, making it impossible to reuse the same film. From the same viewpoint, a T'(30) of -0.2 or less is even more preferable. While there are no limitations on the method of controlling within this range, for example, in the manufacturing process of release film, it can be achieved by applying tension of 0.5 MPa to 5 MPa in both the longitudinal and width directions during the relaxation process in step Z, and controlling the total relaxation rate (hereinafter sometimes referred to as Rx rate) to 4% or less. From the viewpoint of wrinkle suppression, a smaller T'(30) is preferable, but a film with an excessively small T'(30) tends to shrink even when heated, and may shrink excessively when adhering to the mold, preventing it from following the mold properly and potentially causing defects such as tearing of the film. Therefore, a T'(30) of -1.0 or higher is preferable. Furthermore, from the same viewpoint, a T'(30) of -0.8 or higher is more preferable.

[0033] As mentioned above, wrinkles that occur in film include not only those caused by dimensional changes in the film due to temperature fluctuations, but also wrinkles that start from air bubbles remaining in the film when it is adsorbed onto the mold. If the air release properties of the film after it has been adsorbed onto the mold are high, it is possible to prevent the formation of air bubbles during the adsorption process, thereby suppressing the occurrence of wrinkles.

[0034] From this perspective, it is preferable that the release film of the present invention has an air release time of 10 seconds or more and 500 seconds or less on at least one side after being heated and pressed by the following method.

[0035] Heating and pressing method: Using a press machine with the release film heated to 125°C for both the upper and lower molds, a three-layer structure consisting of "SUS304 plate with a thickness of 0.5 mm and an arithmetic mean roughness Ra of 0.1 μm" / release film / "SUS304 plate with a thickness of 0.5 mm and an arithmetic mean roughness Ra of 0.1 μm" is placed between the upper and lower molds. The SUS304 plate used is hairline finished and has a maximum height Rz (JIS B0601-2001) of 2 μm or less. After a preheating time of 5 minutes, heating and pressing is performed for 10 minutes under conditions of 4.0 MPa.

[0036] By keeping the air release time after pressing within the above range, the occurrence of wrinkles can be suppressed. It is difficult to keep the air release time below 10 seconds, and from the viewpoint of suppressing wrinkles, it is preferable to keep it below 500 seconds, more preferably below 300 seconds, and most preferably below 200 seconds. The method for controlling the air release time within this range is not limited, but creating an uneven surface on the film is a suitably used method. From the viewpoint of keeping the air release time within the above range, the average center surface roughness SRa is preferably 0.2 μm or more, more preferably 0.3 μm or more, and most preferably 0.4 μm or more. From the viewpoint of suppressing wrinkles, there is no upper limit to the average center surface roughness SRa, but from the viewpoint of suppressing a decrease in release properties and moldability due to uneven surface irregularities, it is preferable to keep it below 1.5 μm.

[0037] Methods for creating an uneven surface on a film include kneading particles into the substrate and adding particles to a release layer before coating. However, from the viewpoint of preventing contamination of the process due to the shedding of added particles, the method of kneading particles into the substrate is preferably used. The average particle size of the added particles is preferably 1.0 μm or larger, as this enhances the shape-forming effect due to particle inclusion; more preferably 1.5 μm or larger; and most preferably 2.0 μm or larger.

[0038] Furthermore, it is preferable to set the average particle size of the particles contained in the resin layer to 15 μm or less, as this suppresses the reduction in release properties and moldability due to uneven surface irregularities. Specific examples of particles to be added include metals such as gold, silver, copper, platinum, palladium, rhenium, vanadium, osmium, cobalt, iron, zinc, ruthenium, praseodymium, silica, chromium, nickel, aluminum, tin, titanium, tantalum, zirconium, antimony, indium, yttrium, and lanthanium; metal oxides such as zinc oxide, titanium oxide, cesium oxide, antimony oxide, tin oxide, indium tin oxide, yttrium oxide, lanthanium oxide, zirconium oxide, aluminum oxide, and silicon oxide; metal fluorides such as lithium fluoride, magnesium fluoride, aluminum fluoride, and cryolite; metal phosphates such as calcium phosphate; carbonates such as calcium carbonate; sulfates such as barium sulfate; aluminosilicates such as zeolites; and other carbon-based materials such as talc and kaolin, carbon black, fullerenes, chopped or milled carbon fibers, and carbon nanotubes.

[0039] <Method for manufacturing the base layer> The substrate layer of the present invention may be a single-layer structure, or it may be a structure in which layers A and B having different resin compositions are laminated together. The laminated structure may also be a two-layer structure such as layer A / layer B, a three-layer laminated structure such as layer A / layer B / layer A where layer A is laminated on both sides of layer B, or a multiple-layer laminated structure of 3 to 10,000 layers alternatingly. Furthermore, it may be a three-layer structure in which layers A, B, and C having different resin compositions are laminated in order.

[0040] The release film for semiconductor molding of the present invention is preferably stretched in at least one direction from the viewpoint of dimensional stability, mechanical strength, flatness, and thickness uniformity. When biaxial orientation is desired, it can be obtained by a sequential biaxial stretching method in which the unstretched film is stretched in the longitudinal direction and then in the width direction, or in the width direction and then in the longitudinal direction, or by a simultaneous biaxial stretching method in which the longitudinal and width directions of the film are stretched almost simultaneously. Alternatively, the film may be further stretched in the longitudinal or width direction after biaxial orientation. In this invention, the machine flow direction (MD direction) is defined as the longitudinal direction, and the direction perpendicular to the longitudinal direction is defined as the width direction (TD direction). However, if the longitudinal and width directions of the film are unknown, the Young's modulus is measured in any one direction of the film (0°) and in directions at 15°, 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135°, 150°, and 165° from that direction. The direction with the highest Young's modulus is considered the width direction, and the direction perpendicular to the width direction is considered the longitudinal direction.

[0041] In this stretching method, the stretching ratio for the first axis is preferably 2.5 times or more and 4.0 times or less. If the stretching ratio for the first axis is less than 2.5 times, orientation crystallization will not proceed sufficiently, the film will be more prone to expansion due to heat, and wrinkles will easily form. Furthermore, the stretching speed is preferably 5,000% / min or more and 100,000% / min or less. In addition, the preheating temperature is preferably 30°C or more below the glass transition temperature of the resin and 10°C or less below the glass transition temperature of the resin, and the stretching temperature is preferably 40°C or more above the glass transition temperature of the resin.

[0042] The secondary stretching ratio is preferably 2.8 times or more and 4.2 times or less. The secondary stretching speed is preferably 500% / min or more and 100,000% / min or less. Furthermore, the preheating temperature is preferably 20°C or more above the glass transition temperature of the resin and 20°C or less above the glass transition temperature of the resin, and the stretching temperature is preferably 60°C or more above the glass transition temperature of the resin.

[0043] Furthermore, the film is heat-treated after biaxial stretching. The heat treatment can be carried out by any conventionally known method, such as in an oven. Preferably, this heat treatment is performed in a temperature atmosphere of -40°C or higher and Tm-5°C or lower than the film's crystal melting peak temperature (Tm). Setting the heat treatment temperature to Tm-40°C or higher allows for sufficient relaxation of the stretch stress, improving moldability during compression molding. Also, setting the heat treatment temperature to Tm-5°C or lower enables stable film formation. In this process, relaxation treatment can be performed in both the longitudinal and width directions. Preferably, this relaxation treatment is performed within a range of ±20° in the longitudinal direction when performed in the longitudinal direction, and within a range of ±20° in the width direction when performed in the width direction. From the viewpoint of dimensional stability, it is preferable to perform relaxation treatment in two or more stages in at least one of the longitudinal or width directions, and the total relaxation ratio is preferably 4% or less. Furthermore, from the viewpoint of controlling S(150) in the final heat treatment step, it is preferable to apply and maintain a tension of 0.5 MPa to 5 MPa in both the longitudinal and width directions within a temperature range of 50°C to 190°C.

[0044] The heat treatment time can be set arbitrarily within a range that does not degrade the properties, but it is preferable to set it to 5 seconds or more and 60 seconds or less, as this enhances the effect of the heat treatment temperature as described above. From the same viewpoint, a heat treatment time of 7 seconds or more and 40 seconds or less is more preferable, and 10 seconds or more and 25 seconds or less is even more preferable.

[0045] <Release layer> The release film preferably has a peel force of 100 mN / cm or less from the mold resin, as evaluated by the method described below. By suppressing the peel force to a low level, the film and molded product can be easily separated after molding, contributing to efficient production. The method for controlling the peel force within this range is not particularly limited, but by suppressing the occurrence of wrinkles using the method described above, the increase in peel force starting from wrinkles can be reduced, and low peeling can be achieved.

[0046] In the present invention, the release layer is preferable because it contains a binder resin, which improves adhesion to the substrate layer and allows adjustment of the release force to the object to be removed. Specific examples of binder resins include polyester resin, polystyrene resin, acrylic resin, urethane resin, polyvinyl, polyalkylene glycol, polyalkyleneimine, cellulose, starches, etc., but polyester resin and acrylic resin are preferably used from the viewpoint of improving moldability and release properties.

[0047] The polyester resin described above is preferably one having ester bonds in its main chain or side chains, and is obtained by polycondensation of a dicarboxylic acid and a diol. Aromatic, aliphatic, and alicyclic dicarboxylic acids can be used as raw materials for the polyester resin. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-bisphenoxyethane-p-p'-dicarboxylic acid, and phenylindanedicarboxylic acid. Examples of aliphatic and alicyclic dicarboxylic acids include succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedionic acid, dimer acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and their ester-forming derivatives. These may be used individually or in combination.

[0048] The diol components used as raw materials for the polyester resin include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl- 1,6-Hexanediol, 1,2-Cyclohexanedimethanol, 1,3-Cyclohexanedimethanol, 1,4-Cyclohexanedimethanol, 2,2,4,4-Tetramethyl-1,3-Cyclobutanediol, 4,4'-Thiodiphenol, Bisphenol A, 4,4'-Methylenediphenol, 4,4'-(2-Norbornylidene)diphenol, 4,4'-Dihydroxybiphenol, o-, m-, and p-Dihydroxybenzene, 4,4'-Isopropylidenephenol, 4,4'-Isopropylidenebinediol, Cyclopentane-1,2-Diol, Cyclohexane-1,2'-Diol, Cyclohexane-1,2-Diol, Cyclohexane-1,4-Diol, etc. can be used. These can be used individually or in combination of multiple types.

[0049] Furthermore, it is also possible to use modified polyester copolymers, such as block copolymers or graft copolymers modified with acrylic, urethane, epoxy, etc. Examples of the above-mentioned acrylic resins include homopolymers or copolymers of alkyl (meth)acrylate esters, and (meth)acrylate ester copolymers having curable functional groups in the side chains and / or main chain ends. Examples of curable functional groups include hydroxyl groups, carboxyl groups, epoxy groups, and amino groups. Among these, acrylic monomer copolymers obtained by copolymerizing an acrylic monomer with an acrylic ester having curable functional groups in the side chains and / or main chain ends are preferred.

[0050] Furthermore, it is preferable to add a crosslinking agent as a component of the release layer. By using various crosslinking agents in combination with the aforementioned resin, the heat resistance can be dramatically improved. The crosslinking agent is preferably one or more selected from oxazoline resin, melamine resin, epoxy resin, carbodiimide resin, and isocyanate resin. From the viewpoint of the release layer's resistance to solvents, melamine resin is even more preferably used. The crosslinking agent can be mixed and used in any ratio, but in terms of improving release properties, it is preferable to add 5 parts by mass or more and 50 parts by mass or less of the crosslinking agent per 100 parts by mass of the binder resin, and more preferably 10 parts by mass or more and 40 parts by mass or less. If the amount of crosslinking agent added is less than 5 parts by mass, the release effect may be insufficient, or scratches may occur during roll transport. Also, by setting it to 50 parts by mass or less, unevenness is more likely to occur during application, which can prevent a decrease in release properties.

[0051] In the present invention, it is preferable that the resin composition forming the release layer contains an additive suitable for imparting release properties, in addition to the binder resin and crosslinking agent. The additive is preferably in an amount of 3 parts by mass or more and 50 parts by mass or less, when the sum of the masses of the binder resin and crosslinking agent is 100 parts by mass. By adding 3 parts by mass or more of the additive, release properties can be imparted, and by adding 50 parts by mass or less, it is possible to impart heat resistance to the release layer that can withstand compression molding, and as a result, the decrease in release properties can be suppressed. Preferably, it is 10 parts by mass or more and 42 parts by mass or less, and most preferably 20 parts by mass or more and 34 parts by mass or less.

[0052] In this invention, the term "additive" refers to a compound that, when added to a resin, has mold-release properties on the surface of the resin. Specifically, examples include silicone-containing compounds, fluorine compounds, waxes such as paraffin wax, polyethylene wax, and carnauba wax, long-chain alkyl group-containing compounds, and resins. Among these, long-chain alkyl group-containing compounds are preferred from the viewpoint of suppressing mold release and surface defects. In this invention, the term "long-chain alkyl compound" refers to a compound having a long-chain alkyl group, and is not particularly limited as long as it contains a long-chain alkyl group, but examples include those having a long-chain alkyl group in the side chain of the main chain polymer.

[0053] In compounds having a long-chain alkyl group in the side chain of the main chain polymer, examples of main chain polymers include acrylate-based polymers or copolymers, polyvinyl alcohol (including partially saponified polyvinyl acetate), ethylene-vinyl alcohol copolymer (including partially saponified ethylene-vinyl acetate copolymer), vinyl alcohol-acrylic acid copolymer (including partially saponified vinyl acetate-acrylic acid copolymer), polyethylimine, polyvinylamine, styrene-maleic anhydride copolymer, and polyurethane.

[0054] A preferred embodiment of the laminated film in the present invention is characterized in that a release layer is provided on one or both sides of the base layer.

[0055] Providing a release layer on only one side of the base layer is preferable because it shortens the manufacturing process of the release layer. Furthermore, providing a release layer on both sides of the base layer is preferable because it also provides release properties to the mold, preventing precipitated oligomers from adhering to the mold.

[0056] Methods for providing a release layer on a substrate layer include: dissolving or dispersing the resin composition of the release layer in a solvent and applying it to the substrate layer, drying the solvent after application, and then heating it; melt co-extruding the resin composition of the release layer together with the substrate layer to form a sheet together with the substrate layer using the method described above; extruding the molten resin composition of the release layer onto a substrate layer that has been subjected to processing such as corona treatment to provide a resin layer; and laminating a substrate layer and a release layer that are manufactured separately. Among these, the method of applying the release layer is preferred from the viewpoint of being able to freely select the preferred binder resin, additives, and crosslinking agents.

[0057] Methods for applying a release layer to a substrate layer include uniform application using a metering bar or gravure roll followed by drying in an oven, or in-line coating of the release layer. In particular, in-line coating, which includes a drying process at a temperature of 50°C or higher while applying tension in both the longitudinal and width directions, is preferable from the viewpoint of controlling S(150).

[0058] A specific method for providing a release layer by in-line coating is to uniformly apply a dissolved or dispersed resin composition of the release layer onto a film that has been at least uniaxially stretched during the manufacturing process of the base layer, using a metering ring bar or gravure roll, and then dry the coating while stretching it. By performing the above method, the thickness of the release layer can be made more uniform. In addition, by increasing the molecular affinity with the base layer, the adhesion between the base layer and the release layer can be improved, and the degree of hardening of the coating film is increased by heat treatment at a higher temperature compared to offline coating, improving heat resistance and chemical resistance, while also having the advantage of eliminating or shortening the aging treatment after manufacturing.

[0059] In the present invention, the laminated film is preferable because the release layer thickness after drying is 10 nm or more, which allows the release layer to maintain conformity to the surface shape of the substrate layer even when subjected to high pressure such as in a compression mold. Furthermore, a release layer thickness of 2000 nm or less after drying is preferable because it enhances the design without impairing the uneven shape of the substrate layer. From a similar viewpoint, the release layer thickness after drying is more preferably 50 nm or more and 1500 nm or less, and even more preferably 100 nm or more and 1200 nm or less.

[0060] Similarly, if particles are included in the release layer, it may lead to a decrease in release properties due to unevenness and process contamination due to particle detachment. It is preferable that the particle content in the release layer be 4% by mass or less per 100% by mass of the layer, as this allows for both release properties and moldability without hindering the effects of the surface shape of the base layer. It is more preferable that the particle content in the release layer be 1% by mass or less, and even more preferable that it be free of particles.

[0061] In the present invention, the release surface of the laminated film is preferable if the water contact angle is 85° or higher, as this improves release properties. Furthermore, a water contact angle of 120° or lower is preferable because it improves the conformability of the mold resin and enhances the design. From a similar viewpoint, a water contact angle of 90° or higher and 115° or lower is more preferable, and 95° or higher and 110° or lower is even more preferable.

[0062] <Manufacturing method for semiconductor chip encapsulants> A method for manufacturing a semiconductor chip encapsulant using the semiconductor mold release film of the present invention includes stacking the release film, a silicon wafer on which a semiconductor chip is placed, or a resin substrate in order in a molding apparatus, placing a measured amount of molding resin on the wafer, then transporting the release film of the present invention from the top so that the release layer side faces the molding resin side, vacuum adsorption, and performing compression pressing while heating the mold. That is, a preferred embodiment of the semiconductor chip encapsulant manufacturing method of the present invention is a method for manufacturing a semiconductor chip encapsulant that includes a step of performing compression molding by placing the release film of the semiconductor mold release film in a mold inside a compression apparatus so that the release layer and the molding resin are in contact. At this time, since the release film of the present invention is located between the molding resin and the mold, a design is required that is excellent in moldability and release properties while simultaneously forming a surface shape on the resin surface to provide aesthetic appeal.

[0063] As described above, the release film of the present invention can suppress the occurrence of wrinkles during compression molding, thereby reducing the occurrence of defects caused by wrinkles. In the molding process, the higher the mold temperature, the greater the expansion rate of general release films, and the lower their bending rigidity, making them more prone to wrinkles. From this perspective, this release film can be suitably used in molding processes at low temperatures of 110°C to 125°C, but it is particularly suitable for use under high-temperature conditions of 125°C to 190°C, as it can suppress the occurrence of wrinkles even under these conditions. Furthermore, in recent years, packages such as PLP (Panel Level Packages) have emerged where the mold resin covers a large area of ​​the substrate. As a result, as the mold size increases, the force that adheres the film to the mold by vacuuming decreases due to the increased surface area, which tends to make the film more prone to wrinkles. This release film is suitable for molds where the mold resin covers an area of ​​650 cm². 2 It can be suitably used in relatively large-area molding processes as described above, and the occurrence of wrinkles can be suppressed. The area covered by the molding resin on the substrate can be up to 15,000 cm² from the viewpoint of handling and other factors. 2 The following applies:

[0064] Furthermore, as the substrate area increases, package warping due to the difference in the coefficient of thermal expansion between the molding resin and the substrate becomes more pronounced, making defects more likely. To suppress warping, it is preferable to add inorganic particles, which are fillers, to the molding resin. The smaller the maximum particle size, the better. Preferably, the maximum particle size is 1 μm to 80 μm, more preferably 1 μm to 50 μm, and most preferably 1 μm to 30 μm. By controlling within this range, warping during the molding process can be suppressed. Note that reducing the particle size increases the viscosity of the molding resin, making the release film more likely to get caught in the molding resin and causing wrinkles. However, the occurrence of wrinkles can be reduced by using the semiconductor molding release film described here.

[0065] Furthermore, from the viewpoint of air release, if the mold surface of the molding device used also has an uneven shape, the occurrence of wrinkles due to trapped air bubbles can be suppressed. From the viewpoint of wrinkle suppression, it is preferable that the sum of the SRa of the surface of the semiconductor mold release film that contacts the mold after heating and pressing, and the SRa of the mold surface of the molding device used, be 0.3 μm or more and 3.0 μm or less, and more preferably 0.4 μm or more and 2.5 μm or less.

[0066] <Semiconductors> The semiconductor of the present invention is characterized by the fact that a large-scale circuit integrated on a single chip is deliberately fragmented into multiple small chips, mounted on a substrate called an interposer that connects the chiplets, and then enlarged and housed in a single package. The use of chiplets allows for the housing of large-scale circuits combining chiplets from different process nodes (generations of microfabrication technology) and different process technologies (logic, memory, analog ICs, RF circuits, power semiconductors, etc.) in a single package. In other words, the semiconductor of the present invention consists of multiple semiconductor elements connected via an interposer in a single package. Furthermore, as described above, because the semiconductor of the present invention houses multiple semiconductor elements via an interposer, the area is 100 mm². 2 More than 250000mm 2The following is preferable. For similar reasons, the semiconductor of the present invention preferably has a mold resin thickness of 0.1 mm or more and 2.5 mm or less. Furthermore, the semiconductor has a chroma unevenness ΔC when measured by (15) chroma unevenness. * It is preferable that the value is between 0 and 0.20. Saturation unevenness ΔC * By setting the above range, a high-quality semiconductor package can be obtained that is free of wrinkles not only visible on the semiconductor surface but also when observed under a microscope. From the viewpoint of keeping ΔC* within the above range, it is preferable that the semiconductor package of the present invention be obtained by a manufacturing method using the semiconductor mold release film of the present invention.

[0067] [Methods for measuring and evaluating characteristics] (1) Composition of polyester Dissolve the film in hexafluoroisopropanol (HFIP), 1 H-NMR and 13 The content of each monomer residue component is quantified using 1C-NMR. In the case of laminated films, the components constituting each layer are collected and evaluated by scraping off each layer of the film according to the laminate thickness.

[0068] (2) Cross-sectional observation of the release film The film is embedded in epoxy resin, and two cross-sections—one in an arbitrary direction and the other perpendicular to it—are cut perpendicular to the thickness direction using a known method (microtome method or ion milling method) suitable for the type of particles. The cross-sections are then observed using either a transmission electron microscope (Hitachi TEM H7100) or a scanning electron microscope (JEOL SEM JSM-6700F).

[0069] (3) Release film thickness, base film thickness, release layer thickness Using the method described above, select a magnification that allows observation of the release film thickness, base film thickness, and release layer thickness. Acquire images of three different points in two different cross-sections, and calculate the average value of the total of six images.

[0070] (4) Young's modulus A rectangular section measuring 150 mm in length and 10 mm in width is cut from the film at an arbitrary position along the longitudinal direction (MD) to form a sample. A tensile test is performed along the longitudinal direction of the film using a tensile testing machine (Orientec "Tensilon" (registered trademark) UCT-100) according to the method specified in JIS Z1702 (1994), with an initial tensile chuck distance of 50 mm and a tensile speed of 300 mm / min. Five samples are taken at arbitrary positions, and the average value obtained from each sample is adopted. The Young's modulus in the width direction (TD) is also determined in the same manner. In this invention, the machine flow direction (MD direction) is defined as the longitudinal direction, and the direction perpendicular to the longitudinal direction is defined as the width direction (TD direction). However, if the longitudinal and width directions of the film are unknown, the Young's modulus is measured in any one direction of the film (0°) and in directions at 15°, 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135°, 150°, and 165° from that direction. The direction with the highest Young's modulus is considered the width direction (TD direction), and the direction perpendicular to the width direction is considered the longitudinal direction (MD direction).

[0071] (5)Thermomechanical analysis (TMA) The film was cut into rectangular pieces measuring 50 mm in length and 4 mm in width along its longitudinal and lateral directions to form samples. Using a thermomechanical analyzer (Seiko Instruments, TMA EXSTAR6000), the dimensional changes were measured under the following conditions when the temperature was increased from 25°C to 170°C and then decreased from 170°C to 25°C. Trial length: 20mm Load: 29.4mN Temperature rise / fall rate: 10°C / min Measurement temperature range: 25~170℃ Measurement interval: 2 seconds The dimensional change T(K)(%) during heating at a temperature K(°C) is calculated using the following formula based on the results measured during the above heating process. T(K) = [{Film length at temperature K(°C) during the heating process (mm) - Film length at 30°C during the heating process (mm)} / Film length at 30°C during the heating process (mm)] × 100 The dimensional change T'(30)(%) after cooling at a temperature of 30(°C) is calculated using the following formula based on the results of the above cooling measurement. T'(30) = [{Film length at 30°C during the cooling process (mm) - Film length at 30°C during the heating process (mm)} / Film length at 30°C during the heating process (mm)] × 100 The dimensional change rate S(150)( / °C) at a temperature of 150°C is calculated using the following formula, where K1(°C) is the temperature when the temperature first exceeds 150°C during measurement, and K2(°C) is the temperature observed 2 seconds after K1(°C). S(150)=(T(K2)-T(K1)) / (K2-K1) The measurements were taken five times each in the longitudinal and widthwise directions, changing the sampling position each time. The average value calculated from the obtained measurements was then adopted as the value for each direction.

[0072] (6) Young's modulus E at 150°C, bending stiffness F at 150°C, deflection parameter σ A rectangular sample of 150 mm in length and 10 mm in width is cut from the film at an arbitrary position along the longitudinal direction (MD). A tensile test is performed along the longitudinal direction of the film using a tensile testing machine (Orientec "Tensilon" (registered trademark) UCT-100) with an initial tensile chuck distance of 50 mm and a tensile speed of 300 mm / min. For measurement, the film sample is placed in a constant temperature chamber preheated to 150°C, and after 90 seconds of preheating, the tensile test is performed under air. Sampling is performed at 5 points at arbitrary positions, and the average of the Young's modulus values ​​obtained from each sample is taken as the Young's modulus E (MPa) at 150°C. The bending stiffness at 150°C is defined as the value obtained from the following formula using the obtained Young's modulus E (MPa) at 150°C and the thickness h (μm) of the measurement sample obtained by the method described in (3) Release film thickness, base film thickness, and release layer thickness. Bending rigidity F (mN·mm) 2 ) = (2.5 × E × h) 3 ×10 -6 ) / 12 Furthermore, the deflection parameter σ is the bending stiffness F (mN·mm) at 150°C. 2 (5) Using the dimensional change T(150)(%) at 150°C obtained by thermomechanical analysis (TMA), the following formula is used to calculate it.

[0073] Deflection parameter σ(mN) -1 ·mm -2 ) = T(150) / F Sampling is performed at five points at arbitrary locations, and the average value obtained from each sample is adopted. (7) Peeling force As shown in Figures 2 and 3, a "Kapton" (registered trademark) film is placed on a steel plate, and a 1mm thick metal frame with a 5cm x 5cm square hole is placed on top. 5.0g of molding resin (Nagase ChemteX Co., Ltd.: product name "R4508") is placed in the cavity of the metal frame, and a sample of mold release film measuring 6cm x 10cm is placed on top with the release layer facing the resin side. A "Kapton" (registered trademark) film and a steel plate are then placed on top to create a laminate. This laminate is placed in a heated vacuum press machine heated to 150°C and pressurized at a pressure of 3MPa while maintaining the temperature at 150°C for 10 minutes. After leaving the molded film in an atmosphere of 23°C and 65% relative humidity for 24 hours, the release force between the molded resin and the film is measured using a release tester (Kyowa Interface Chemical Co., Ltd.: Adhesive / film peel analysis device VPA-2) at a peel angle of 90° and a peel speed of 50 mm / min. The average value is calculated for N=5, and the peel force is then calculated.

[0074] (8) Heat of cold crystallization ΔHc, crystal melting peak temperature Tm A 5 mg sample was weighed from the center of the film width using an electronic balance and placed in an aluminum sample pan. The sample was then heated from 25°C to 300°C at a rate of 20°C / min using a Rigaku Thermo plus ECO2 series DSC vesta, in accordance with JIS K7121 (1987) and JIS K7122 (1987). After heating, the sample was cooled to room temperature and then heated again from 25°C to 300°C at a rate of 20°C / min. The melting point Tm was determined from the results of this first measurement using the Rigaku Thermo plus ECO2 system. If multiple melting point peaks were observed, they were named Tm1, Tm2, ​​etc., in descending order of peak temperature. The results of the second measurement were also analyzed using the Rigaku Thermo plus ECO2 system to determine the heat of cold crystallization ΔHc from the obtained DSC data.

[0075] (9) Center surface average roughness SRa The surface morphology of the film will be measured using a 3D micro-morphometer (model ET-4000A, manufactured by Kosaka Research Institute Co., Ltd.) under the following measurement conditions. (Measurement conditions) • Measuring device: 3D micro-shape measuring instrument (model ET-4000A), manufactured by Kosaka Research Institute Co., Ltd. • Stylus: Model ET-1480 (tip radius 0.5 μmR, diameter 2 μm, made of diamond) ·Stylus pressure: 100μN • Measurement direction: Film width direction • X-axis (film width direction) measurement length: 1.0 mm • Y-axis (longitudinal direction of film) measurement length: 0.40 mm ·Measurement speed: 0.1mm / sec • X-axis feed pitch: 1 μm (measurement interval) • Y-axis feed pitch: 5 μm (measurement interval) • Number of Y-axis lines: 81 (number of measurement lines) • Z-axis measurement magnification: 10,000x (vertical magnification) • Evacuation amount: 2mm Next, the obtained measurement data is imported into a 3D surface roughness analysis system (model TDA-31), and the mean center surface roughness SRa, a 3D parameter extended to three dimensions according to JIS-B0601 (1994) as defined in the manual accompanying the measuring instrument and analysis system, is calculated under the following analysis conditions. The above measurement is performed by taking a measurement with an arbitrary direction as the X-axis and another measurement with a direction perpendicular to that direction as the X-axis, and the average of the two measurements is adopted.

[0076] (Analysis conditions) • Analysis equipment: 3D surface roughness analysis system (Model TDA-31) • Filtering method: Gaussian space type • Leveling: Yes, full range (tilt correction) • Low-frequency cutoff: 0.250mm • Low-frequency reserve length: λc × 0.5 • Recommended low-frequency cutoff range: 1 / 5 of the wavelength • High-frequency cutoff: 0mm • High-frequency buffer length: None.

[0077] (10) Hot press Using a press machine with both the upper and lower die temperatures heated to 125°C, a structure consisting of a SUS304 plate with a thickness of 0.5 mm and an arithmetic mean roughness Ra of 0.1 μm, a laminated film, and another SUS304 plate with a thickness of 0.5 mm and an arithmetic mean roughness Ra of 0.1 μm is placed between the upper and lower dies. After a preheating time of 5 minutes, heating and pressing is performed for 10 minutes under conditions of 4.0 MPa. After heating and pressing, the laminated film is removed and heated and pressed between the metal plates. The SRa of the laminated film after heating and pressing is measured by the method described in (9) Center surface average roughness SRa.

[0078] (11) Air release time Using a Digibec smoothness tester manufactured by Toyo Seiki Co., Ltd., the sample was set on the sample stage with the measurement surface aligned with the air intake, a 200g weight was placed on top of the film, the vacuum level was set to 385mmHg using a vacuum pump, and then the vacuum pump was stopped. The time (in seconds) it took for the vacuum level to decrease from 382mmHg to 381mmHg was defined as the air release time. For the measurement, 10cm x 10cm sections of film were randomly cut, and the same location was not measured twice. The average value of 10 measurements taken for each surface was adopted.

[0079] (12) Contact angle of water After leaving the release film in an atmosphere of 23°C and 65% relative humidity for 24 hours, the contact angle of pure water with respect to the measurement surface, which is held horizontally under the same atmosphere, is measured at five points using a contact angle meter DM-501 (manufactured by Kyowa Interface Science Co., Ltd.), and the average of these measurements is taken as the water contact angle.

[0080] (13) Appearance evaluation 1 A silicon wafer with a thickness of 0.775 mm and a diameter of 300 mm (12 inches) is coated with sealing resin (Sumitomo Bakelite G311Q) on one side and placed on the lower mold of a compression mold (average surface roughness of the mold center, SRa = 0.3 μm). A release film is vacuum-suctioned and fixed to the concave upper mold, and then molded to obtain a sealing test sample. The mold temperature is 150°C, the resin pressure is 4 MPa, and the curing time is 5 minutes. 100 of these samples are prepared and evaluated visually and by observing their appearance at 100x magnification using a digital microscope (Keyence VHX-5000), according to the following criteria. A: Wrinkles were observed in one or fewer samples by visual inspection or microscopic observation. B: Two to five samples showed wrinkles upon visual inspection or microscopic observation. C: Six to ten samples showed wrinkles upon visual inspection or microscopic observation. D: Between 11 and 15 samples showed wrinkles upon visual inspection or microscopic observation. E: More than 16 samples showed wrinkles upon visual inspection or microscopic observation.

[0081] (14) Appearance evaluation 2 A silicon wafer with a thickness of 0.775 mm and a diameter of 300 mm (12 inches) is coated with sealing resin (Sumitomo Bakelite G311Q) on one side and placed on the lower mold of a compression mold (average surface roughness of the mold center surface SRa = 0.01 μm). A release film is vacuum-suctioned and fixed to the concave upper mold, and then molded to obtain a sealing test sample. The mold temperature is 175°C, the resin pressure is 4 MPa, and the curing time is 5 minutes. 100 of these samples are prepared and evaluated visually and by observing their appearance at 100x magnification using a digital microscope (Keyence VHX-5000), according to the following criteria. A: Wrinkles were observed in one or fewer samples by visual inspection or microscopic observation. B: Two to five samples showed wrinkles upon visual inspection or microscopic observation. C: Six to ten samples showed wrinkles upon visual inspection or microscopic observation. D: Between 11 and 15 samples showed wrinkles upon visual inspection or microscopic observation. E: More than 16 samples showed wrinkles upon visual inspection or microscopic observation.

[0082] (15) Appearance evaluation 3 A glass substrate measuring 0.8 mm thick and 500 mm x 500 mm in size is coated with sealing resin (Sumitomo Bakelite G311Q) and placed on the lower mold of a compression mold (average surface roughness of the mold center, SRa = 0.01 μm). A release film is vacuum-suctioned and fixed to the concave upper mold, and then molded to obtain a sealing test sample. The mold temperature is 150°C, the resin pressure is 4 MPa, and the curing time is 5 minutes. 100 of these samples are prepared and evaluated visually and by observing their appearance at 100x magnification using a digital microscope (Keyence VHX-5000), according to the following criteria. A: Wrinkles were observed in one or fewer samples by visual inspection or microscopic observation. B: Two to five samples showed wrinkles upon visual inspection or microscopic observation. C: Six to ten samples showed wrinkles upon visual inspection or microscopic observation. D: Between 11 and 15 samples showed wrinkles upon visual inspection or microscopic observation. E: More than 16 samples showed wrinkles upon visual inspection or microscopic observation.

[0083] (16) Appearance Rating 4 A glass substrate measuring 0.8 mm thick and 500 mm x 500 mm in size is coated with sealing resin (Sumitomo Bakelite G311Q) and placed on the lower mold of a compression mold (average surface roughness of the mold center, SRa = 0.01 μm). A release film is vacuum-suctioned and fixed to the concave upper mold, and then molded to obtain a sealing test sample. The mold temperature is 175°C, the resin pressure is 4 MPa, and the curing time is 5 minutes. 100 of these samples are prepared and evaluated visually and by observing their appearance at 100x magnification using a digital microscope (Keyence VHX-5000), according to the following criteria. A: Wrinkles were observed in one or fewer samples by visual inspection or microscopic observation. B: Two to five samples showed wrinkles upon visual inspection or microscopic observation. C: Six to ten samples showed wrinkles upon visual inspection or microscopic observation. D: Between 11 and 15 samples showed wrinkles upon visual inspection or microscopic observation. E: More than 16 samples showed wrinkles upon visual inspection or microscopic observation.

[0084] (17) Appearance of the film after molding test (13) Observe the appearance of 100 film samples used in Appearance Evaluation 1 and evaluate them according to the following criteria. A: Fewer than 20 film samples were unusable due to bending or tearing. B: Fewer than 40 film samples were unusable due to bending or tearing. C: More than 41 film samples were unusable due to bending or tearing.

[0085] (18) Resin chipping of the molded sample (13) Visually inspect the resin edges of the sample obtained in Visual Evaluation 1 and evaluate whether there are any resin chips caused by the resin not being filled to the edge of the mold, and evaluate according to the following criteria. A: One or fewer samples showed visible signs of resin chipping. B: Two to five samples showed visible signs of resin chipping. C: Six to ten samples showed visible signs of resin chipping. D: More than 11 samples showed visible signs of resin chipping.

[0086] (19) Saturation ΔC of semiconductor package Using a Konica Minolta Sensing Co., Ltd. CM-3600d spectrophotometer, the chromaticity (a) at each of 10 arbitrary points on a semiconductor manufactured using the semiconductor mold release film of the present invention was measured. * , b * The chromaticity (a) was measured. Saturation was determined from the obtained chromaticity, and the difference between the maximum and minimum saturation values ​​was defined as the unevenness of saturation. The measurement procedure was as follows: zero configuration of reflectance was performed using the zero configuration box attached to the spectrophotometer, followed by 100% calibration using the attached white calibration plate, and then the chromaticity (a) of the film was measured under the following conditions. * , b * ) was measured.

[0087] Mode: Reflection, SCI / SCE simultaneous measurement Measurement diameter: 8mm Next, chromaticity (a * , b * ) from saturation C * The following was calculated. The definition of saturation is as follows: C * =((a * ) 2 +(b * ) 2 ) 1 / 2 The chromaticity (a) used in the calculation of saturation * , b * The SCI (including specular reflection) value was used. [Examples]

[0088] The present invention will be described below with reference to examples, but the present invention is not necessarily limited to these examples.

[0089] <Resin manufacturing> The resin used for film formation was prepared as follows:

[0090] (Resin A) A polyethylene terephthalate resin (intrinsic viscosity 0.65) containing 100 mol% terephthalic acid as the dicarboxylic acid component and 100 mol% ethylenediol as the diol component.

[0091] (Resin B) A cyclohexanedimethanol copolymer polyethylene terephthalate resin (intrinsic viscosity 0.75) in which 1,4-cyclohexanedimethanol is copolymerized with the diol component at a concentration of 20 mol%.

[0092] (Resin C) Isophthalic acid copolymer polyethylene terephthalate resin (intrinsic viscosity 0.7) in which the isophthalic acid component is copolymerized with the dicarboxylic acid component at a concentration of 10 mol%.

[0093] (Resin D) A masterbatch (intrinsic viscosity 0.65) containing aggregated silica particles (specific gravity 2.2) with an average particle size of 3.5 μm in resin A at a particle concentration of 10% by mass. (Resin E) A masterbatch (intrinsic viscosity 0.65) containing aggregated silica particles (specific gravity 2.2) with an average particle size of 2.0 μm in resin A at a particle concentration of 10% by mass.

[0094] (Resin F) A masterbatch (intrinsic viscosity 0.65) containing aggregated silica particles (specific gravity 2.2) with an average particle size of 1.2 μm in resin A at a particle concentration of 2% by mass.

[0095] <Manufacturing of release layer coatings> The coating material used for the release layer was prepared by mixing the following components.

[0096] (Coating material A) 200 parts by mass of xylene and 600 parts by mass of octadecyl isocyanate were added to a four-necked flask and heated with stirring. From the point when the xylene began to reflux, 100 parts by mass of polyvinyl alcohol with an average degree of polymerization of 500 and a degree of saponification of 88 mol% was added in small amounts at 10-minute intervals over approximately 2 hours. After the addition of polyvinyl alcohol was completed, reflux was continued for another 2 hours to terminate the reaction. The reaction mixture was then cooled to approximately 80°C and added to methanol, and the resulting white precipitate was filtered off. 140 parts by mass of xylene was added to the obtained white precipitate, heated to completely dissolve it, and then methanol was added again to precipitate it. This process was repeated several times. The obtained precipitate was then washed with methanol and dried and ground to obtain a long-chain alkyl group-containing resin (having an alkyl group with 18 carbon atoms in the side chain) having a hydroxyl group as a reactive functional group. This was diluted with deionized water to a concentration of 20% by mass to obtain release agent 1.

[0097] A release agent 1, a polyester binder, and an oxazoline crosslinking agent were mixed in a solid content mass ratio of 8 / 60 / 32. Next, water was added to adjust the solid content concentration according to the target coating film thickness. Furthermore, 3 parts by mass of p-toluenesulfonic acid were added to 100 parts by mass of the entire mixed coating composition, and an acetylenediol-based surfactant was added to 0.4 parts by mass of the entire mixed coating composition to obtain a coating composition for forming a resin layer.

[0098] (Coating material B) A paint composition was obtained by mixing 10 parts by mass of long-chain alkyl group-containing polyvinyl resin (based on solid content), 2.5 parts by mass of melamine-based crosslinking agent (based on solid content), 1.5 parts by mass of p-toluenesulfonic acid (based on solid content), 200 parts by mass of toluene, and 70 parts by mass of methyl ethyl ketone.

[0099] <Manufacturing of release films for semiconductor molds> (Examples 1-12, 16, 17, Comparative Example 2) Mixed raw materials according to the composition shown in the table were supplied to separate twin-screw extruders with vents and an oxygen concentration of 0.2 volume%. The extruder cylinder temperature for the A-layer resin was set to 270°C, and the extruder cylinder temperature for the B-layer polyester resin resin was set to 280°C to melt the material. After the A-layer and B-layer polyester resin resins merged, the short-pipe temperature was set to 270°C, and the die temperature was set to 270°C. The material was extruded in a sheet form with an A-layer / B-layer / A-layer laminate structure onto a cooling drum temperature controlled to 25°C from the T-die. At this time, electrostatic discharge was applied using a wire electrode with a diameter of 0.1 mm to ensure close contact with the cooling drum and obtain an unstretched sheet. The side in contact with the drum surface was designated as the D-side, and the opposite side as the ND-side. Next, before stretching in the longitudinal direction, the film temperature was raised using a heated roll. After stretching in the longitudinal direction at the stretching ratio and stretching temperature shown in Table 2, it was immediately cooled with a metal roll temperature controlled to 30°C.

[0100] After the obtained uniaxially oriented film was subjected to corona discharge treatment in air, coating material A, as described in Table 2, was applied to a thickness of approximately 6 μm using a wire bar coat. Next, the uniaxially oriented film coated with the material was gripped at both ends in the width direction with clips and guided to a tenter-type transverse stretcher. Then, after preheating at a preheating temperature of 85°C in the tenter-type transverse stretcher, it was stretched in the width direction at the stretching ratio and stretching temperature described in Table 2. As heat treatment 1, the film was gripped in the width direction and tension was applied in the longitudinal and width directions while it was relaxed in the width direction at the temperature and relaxation rate described in Table 2. As heat treatment 2, the film was gripped in the width direction and tension was applied in the longitudinal and width directions while it was relaxed in the width direction at the temperature and relaxation rate described in Table 2, to obtain a release film for semiconductor molding with the thickness described in the table. Note that heat treatment 2 was the last step in the film manufacturing process, which involved holding the film at a temperature in the range of 50°C to 190°C.

[0101] When an appearance evaluation test was performed using the release films described in Examples 1-4 and 7, the occurrence of wrinkles was relatively good due to the high thermal dimensional stability.

[0102] Examples 5 and 6 exhibited high thermal dimensional stability, but the surface irregularities were small, and wrinkles formed under relatively harsh conditions, possibly due to trapped air bubbles. However, this was within a range that did not pose a practical problem.

[0103] Examples 8-12, 16, and 17 did not have proper control over the film formation conditions or the crystallinity of the film, resulting in some wrinkles under relatively harsh conditions such as appearance evaluations 2, 3, and 4. However, these were within a range that did not pose a practical problem.

[0104] In Comparative Example 2, the film had high amorphous properties, and as a result of not being able to properly control dimensional stability and the deflection parameter σ, many wafers developed wrinkles in the appearance evaluation test 1, and the evaluation result was poor.

[0105] (Examples 13-15, Comparative Examples 1 and 3) Mixed raw materials according to the composition shown in the table were supplied to separate twin-screw extruders with vents and an oxygen concentration of 0.2 volume%. The extruder cylinder temperature for the A-layer resin was set to 270°C, and the extruder cylinder temperature for the B-layer polyester resin resin was set to 280°C to melt the material. After the A-layer and B-layer polyester resin resins merged, the short-pipe temperature was set to 270°C, and the die temperature was set to 270°C. The material was extruded in a sheet form with an A-layer / B-layer / A-layer laminate structure onto a cooling drum temperature controlled to 25°C from the T-die. At this time, electrostatic discharge was applied using a wire electrode with a diameter of 0.1 mm to ensure close contact with the cooling drum and obtain an unstretched sheet. The side in contact with the drum surface was designated as the D-side, and the opposite side as the ND-side. Next, before stretching in the longitudinal direction, the film temperature was raised using a heated roll. After stretching in the longitudinal direction at the stretching ratio and stretching temperature shown in Table 2, it was immediately cooled with a metal roll temperature controlled to 30°C. The obtained uniaxially oriented film was gripped at both ends in the width direction with clips and guided to a tenter-type transverse stretcher. Next, after preheating at a preheating temperature of 85°C in the tenter-type transverse stretcher, it was stretched in the width direction at the stretching ratio and stretching temperature shown in Table 2. As heat treatment 1, the film was gripped in the width direction and tension was applied in the longitudinal and width directions while it was relaxed in the width direction at the temperature and relaxation rate shown in Table 2. As heat treatment 2, the film was gripped in the width direction and tension was applied in the longitudinal and width directions while it was relaxed in the width direction at the temperature and relaxation rate shown in Table 2, and release films for semiconductor molding with the thickness shown in the table were obtained.

[0106] Next, in order to form a release layer, the polyester film obtained above was cooled to room temperature, and then coating material B was applied to the D side of the film by roll-to-roll gravure coating method under conditions where tension was applied only in the longitudinal direction without gripping in the width direction. After that, the film was transported to a 110°C oven to pre-dry the coating, and then heated and dried in a 160°C oven under conditions where tension was applied only in the longitudinal direction without gripping in the width direction, to obtain a release film for semiconductor molding with a release layer thickness of 250 nm. Of all the steps in the film manufacturing process that were held at a temperature in the range of 50°C to 190°C, the final step was the heating and drying of the coating in a 160°C oven.

[0107] In Examples 13-15, the film formation conditions and the crystallinity of the film were not properly controlled, resulting in some wrinkles under relatively harsh conditions such as appearance evaluations 2, 3, and 4. However, these were within a range that did not pose a practical problem.

[0108] In comparative examples 1 and 3, the films had high amorphous properties, and as a result of not being able to properly control dimensional stability and the deflection parameter σ, many wafers developed wrinkles in the appearance evaluation test 1, and the evaluation results were poor.

[0109] [Table 1]

[0110] [Table 2]

[0111] [Table 3]

[0112] [Table 4] [Industrial applicability]

[0113] The semiconductor mold release film according to the present invention can suppress the generation of wrinkles during mold forming, and can provide a semiconductor chip encapsulation method and a semiconductor. By suitably using such a release film as a mold release film in the semiconductor encapsulation process, the mass productivity of semiconductor chips can be improved. [Explanation of Symbols]

[0114] 101 mold 102 Release film for molds 103 Silicon wafers 104 Molding resin before curing 105 Mold resin after curing 200 iron plate 210 Release film 211 Base material layer 212 Release layer 220 Mold resin 230 Perforated gold frame 240 “Kapton” (registered trademark) film

Claims

1. A release film comprising a base layer and a release layer, wherein the dimensional change rate S(150) ( / °C) of the film at 150°C, measured by thermomechanical analysis (TMA) in the longitudinal and width directions, satisfies formula (I). -0.030≦S(150)≦0.030...(I) (Method for measuring S(150)) The film was cut into rectangular pieces measuring 50 mm in length and 4 mm in width in both the longitudinal and transverse directions to form samples. Using a thermomechanical analyzer (Seiko Instruments, TMA EXSTAR 6000), the dimensional changes when the temperature was increased from 25°C to 170°C under the following conditions were measured. Trial length: 20mm Load: 29.4 mN Heating rate: 10°C / min Measurement temperature range: 25 to 170°C Measurement interval: 2 seconds The dimensional change T (K) (%) during heating at a temperature K (°C) is calculated using the following formula based on the results measured during the above heating process. T(K) = [{Film length at temperature K during the heating process (mm) - Film length at 30°C during the heating process (mm)} / Film length at 30°C during the heating process (mm)] × 100 The dimensional change rate S(150) ( / °C) at a temperature of 150°C is calculated using the following formula, where K1 (°C) is the temperature when the temperature first exceeds 150°C during measurement, and K2 (°C) is the temperature observed 2 seconds after K1. S(150)=(T(K2)-T(K1)) / (K2-K1) The measurements were taken five times each in the longitudinal and widthwise directions, changing the sampling position each time. The average value calculated from the obtained measurements was adopted as the value for each direction.

2. A release film for semiconductor molding according to claim 1, comprising a base layer and a release layer, wherein the dimensional change rate S(150) ( / °C) of the film at 150°C, measured by thermomechanical analysis (TMA) in the longitudinal and width directions, satisfies formula (I''). -0.030≦S(150)≦0.010...(I'')

3. A release film for semiconductor molds according to claim 1 or 2, wherein the dimensional change T(150)(%) at 150°C, measured by thermomechanical analysis (TMA) in the longitudinal and width directions, satisfies formula (II). -1.5 ≦T (150) ≦ 1.5...(II)

4. The release film for semiconductor molds according to claim 1 or 2, wherein the dimensional change T'(30)(%) of the film at 30°C after cooling from 170°C to 25°C, as measured by thermomechanical analysis (TMA) in the longitudinal and width directions, satisfies the following condition (III). -1.0≦T'(30) ≦0.0...(III) (Method for measuring T'(30)) The film was cut into rectangular pieces measuring 50 mm in length and 4 mm in width in both the longitudinal and transverse directions to form samples. Using a thermomechanical analyzer (Seiko Instruments, TMA EXSTAR 6000), the dimensional changes were measured when the temperature was increased from 25°C to 170°C and then decreased from 170°C to 25°C under the following conditions. Trial length: 20mm Load: 29.4 mN Temperature rise / fall rate: 10°C / min Measurement temperature range: 25 to 170°C Measurement interval: 2 seconds T'(30) = [{Film length at 30°C during the cooling process (mm) - Film length at 30°C during the heating process (mm)} / Film length at 30°C during the heating process (mm)] × 100

5. In both the longitudinal and widthwise directions, the bending stiffness F at 150°C is 1.0 mN·mm ２ The above is 20.0 mN・mm ２ The following is the release film for semiconductor molds according to claim 1 or 2.

6. In the longitudinal and widthwise directions, the deflection parameter σ given by the following equation (IV) is 0.50 mN. －１ mm －１ The following is the release film for semiconductor molds according to claim 1 or 2. σ=T(150) / F...(IV) Note that T(150) is the dimensional change T(150) (%) at 150°C, measured by thermomechanical analysis (TMA), and F is the bending stiffness F at 150°C.

7. A release film for semiconductor molding according to claim 1 or 2, comprising a base layer and a release layer, wherein the air release time on at least one side after heating and pressing by the following method is 10 seconds or more and 500 seconds or less. Heating and pressing method: Using a press machine with the release film heated to 125°C for both the upper and lower molds, a three-layer structure consisting of "SUS304 plate with a thickness of 0.5 mm and an arithmetic mean roughness Ra of 0.1 μm" / release film / "SUS304 plate with a thickness of 0.5 mm and an arithmetic mean roughness Ra of 0.1 μm" is placed between the upper and lower molds. The SUS304 plate used is hairline finished and has a maximum height Rz (JIS B0601-2001) of 2 μm or less. After a preheating time of 5 minutes, heating and pressing is performed for 10 minutes under conditions of 4.0 MPa.

8. The release film for semiconductor molds according to claim 1 or 2, wherein the release layer contains a long-chain alkyl group-containing compound.

9. A release film for semiconductor molds according to claim 1 or 2, wherein the peel force measured under the following conditions is 0 mN / cm or more and 100 mN / cm or less. (Measurement method, conditions) A "Kapton" (registered trademark) film is placed on a metal plate, and then a 1mm thick metal frame with a 5cm x 5cm square hole is placed on top. 5.0g of molding resin (Nagase ChemteX Co., Ltd.: product name "R4508") is placed in the cavity of the metal frame, and a sample of mold release film measuring 6cm x 10cm is placed on top with the release layer facing the resin side. Next, a laminate is created by covering it with a "Kapton" (registered trademark) film and an iron plate. This laminate is placed in a heated vacuum press machine heated to 150°C and pressurized at a pressure of 3 MPa while being held at 150°C for 10 minutes. After being left for 24 hours in an atmosphere of room temperature 23°C and relative humidity 65%, a peel test is performed on the release film using a peel test machine (Kyowa Interface Chemical Co., Ltd.: Adhesion / film peel analysis device VPA-2) at a peel angle of 90° and a peel speed of 50 mm / min. The peel force between the mold resin and the film is measured for N=5, the average value is calculated, and the peel force is calculated.

10. A release film for semiconductor molds according to claim 1 or 2, comprising a base layer mainly composed of polyester resin and a release layer provided on the base layer, wherein the copolymer content of the base layer is 3 mol% or more and 12 mol% or less.

11. A method for manufacturing a semiconductor, comprising using the release film for semiconductor molding described in claim 1 or 2 in a step of covering a semiconductor element with a molding resin.

12. The semiconductor manufacturing method according to claim 11, wherein the sum of the center surface average roughness SRa of the surface of the release film for semiconductor molding that contacts the mold after heating and pressing, and the center surface average roughness SRa of the mold surface of the molding apparatus used, is 0.5 μm or more and 3.0 μm or less. Heating and pressing method: Using a press machine with the release film heated to 125°C for both the upper and lower molds, a three-layer structure consisting of "SUS304 plate with a thickness of 0.5 mm and an arithmetic mean roughness Ra of 0.1 μm" / release film / "SUS304 plate with a thickness of 0.5 mm and an arithmetic mean roughness Ra of 0.1 μm" is placed between the upper and lower molds. The SUS304 plate used is hairline finished and has a maximum height Rz (JIS B0601-2001) of 2 μm or less. After a preheating time of 5 minutes, heating and pressing is performed for 10 minutes under conditions of 4.0 MPa.

13. The method for manufacturing a semiconductor according to claim 11, wherein the molding resin contains inorganic particles, and the maximum particle size of the inorganic particles is 1 μm or more and 80 μm or less.

14. In the process of covering a semiconductor element with the aforementioned molding resin, the area covered by the molding resin on the substrate is 650 cm². ２ More than 15000cm ２ The semiconductor manufacturing method according to claim 11, which is as follows:

15. A semiconductor molded with a molding resin, wherein the molding resin contains inorganic particles, the maximum particle size of the inorganic particles is 1 μm or more and 80 μm or less, the thickness of the molding resin is 0.1 mm or more and 2.5 mm or less, and the element area of the semiconductor is 100 mm ２ or more and 250,000 mm ２ or less, the semiconductor has a plurality of semiconductor elements integrated into one package via an interposer, and the color difference ΔC ＊ measured by a colorimeter is 0.20 or less.

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