Release film for semiconductor mold, method for manufacturing semiconductor chip encapsulated body, and semiconductor

Abstract

To provide a release film for compression molding that is less likely to leave peeling residue and that suppresses film tearing, and a method for manufacturing a semiconductor chip encapsulated body.SOLUTION: A release film for a semiconductor mold is a laminated film containing a release layer and a polyester resin layer, and has a film rigidity at 175°C in either the longitudinal or transverse direction of 5.0 N mm 10-3 or more and 20 N mm 10-3 or less, and the number of protrusions with a height of 1 μm or more on at least one of the outermost layers is 500 pieces / mm2 or more and 8000 pieces / mm2 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a release film used in the processing step of semiconductor mold packaging, and in particular, can be suitably used as a release film for compression molding carried out in the semiconductor encapsulation step. [Background technology]

[0002] Semiconductor chips are encapsulated 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. Epoxy resin and other hardening resins are used to encapsulate semiconductor chips. Known methods for encapsulating semiconductor chips include transfer molding (resin flow molding) and compression molding. However, in recent years, the introduction of compression molding has been progressing due to trends such as larger semiconductor wafers, thinner packages, and increased pin counts to accommodate more input terminals.

[0003] Compression molding is a technique in which molten encapsulating resin is compressed and hardened by moving a mold up and down while heated. This technique is used to manufacture an ultra-small packaging technology known as wafer-level chip-size packaging (WL-CSP). To ensure the mold-molding process, a release film is typically inserted to ensure the mold can be easily released. Ethylene-tetrafluoroethylene copolymer (ETFE) films have been widely used as release films, due to their excellent release properties, heat resistance, and mold conformability. However, because the gas generated by the hardening molding resin is highly permeable and prone to contaminating the mold, investigations are underway to find low-gas-permeable materials, primarily polyesters (Patent Document 1).

[0004] Among polyester films, in the case of release films based on polyethylene terephthalate (PET) film, which has excellent dimensional stability, it is necessary to provide a release layer separate from the base film, and release films in which polyethylene terephthalate is mainly used as a heat-resistant resin layer and polymethylpentene as a release layer are laminated together (Patent Document 2). Also, in order to impart design, a method is often used in which particles or other components that impart roughness to the release layer are added (Patent Document 3).

[0005] Furthermore, in recent years, technological trends such as larger semiconductor wafers, lower package heights, higher integration, 3D stacking, and functional integration have led to the widespread adoption of compression molding, and fan-out wafer-level packaging (FO-WLP) technology, in which package sizes exceed chip sizes, is expanding. Figure 1 shows a schematic diagram of the face-up compression molding process used to manufacture FO-WLP. Release films for compression molding, which offer excellent design and formability, are being investigated as release films compatible with these cutting-edge packaging technologies (Patent Document 4). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-158242 [Patent Document 2] Patent Publication No. 2021-28177 [Patent Document 3] Japanese Patent Application Laid-Open No. 2024-16755 [Patent Document 4] Japanese Patent Application Publication No. 2023-154397 Summary of the Invention [Problem to be solved by the invention]

[0007] In the latest packaging technologies, in addition to flange molding, in which the molding resin remains inside the wafer, full molding, in which the molding resin is thicker than 1.0 mm and even extends to the outside of the wafer, is being used to improve yield. In the full molding method, the increased thickness of the molding resin means that the film described in Patent Document 4, which has been used until now, lacks film rigidity at high temperatures, raising the risk of film tearing during molding. If film tearing occurs, resin leakage from the tear can occur, potentially contaminating the mold. Furthermore, Patent Documents 2 and 3 use biaxially oriented PET film, which is not particularly designed for moldability, resulting in poor mold conformability during compression molding and the risk of peeling residue due to localized uneven pressure.

[0008] Therefore, an object of the present invention is to provide a release film for a semiconductor mold that is less likely to leave peeling residue and that also suppresses film breakage, a method for producing a semiconductor chip encapsulated body, and a semiconductor. [Means for solving the problem]

[0009] In order to solve the above problems, a preferred embodiment of the present invention has the following configuration. (1) A laminated film containing a release layer and a polyester resin layer, and the film stiffness at 175°C in either the longitudinal or transverse direction is 5.0 N·mm·10 -3 More than 20N mm 10 -3 and the number of protrusions with a height of 1 μm or more on at least one of the outermost layers is 500 / mm 2 More than 8000 pieces / mm 2 A semiconductor mold release film as follows: (2) The release film for a semiconductor mold according to (1), wherein the polyester resin layer is a laminate of two or more layers having at least a polyester resin A layer and a polyester resin B layer, the inorganic particle content of the polyester resin A layer is 5% by mass or more and 19% by mass or less, and the inorganic particle content of the polyester resin B layer is less than 5% by mass. (3) A release film for a semiconductor mold according to (1) or (2), which has a breaking stress at 175°C of 20 MPa or more and 100 MPa or less in both the longitudinal and transverse directions. (4) The release film for a semiconductor mold according to any one of (1) to (3), which has a cushioning factor of 60% or more and less than 88%. (5) A release film for a semiconductor mold according to any one of (1) to (4), wherein the void content Va of the polyester resin A layer is 10.0% or more and 30.0% or less, and the void content Vz of the entire film is 2.0% or more and 10.0% or less. (6) Density is 1.10 g / cm 3 More than 1.34g / cm 3 The release film for a semiconductor mold according to any one of (1) to (5) below: (7) The release film for a semiconductor mold according to any one of (1) to (6), which has an optical density of 0.1 or more and 2.0 or less. (8) After heating at 185°C for 30 minutes, the oligomer extraction amount was 0 mg / m 2 More than 5.0mg / m 2 The release film for a semiconductor mold according to any one of (1) to (7) below: (9) The release film for a semiconductor mold according to any one of (1) to (8), having a crystallinity of 3.0% or more and 21.0% or less. (10) A method for producing a semiconductor chip sealed body, comprising the step of placing the release film for semiconductor molding according to any one of (1) to (9) in a mold in a compression device so that the release layer and molding resin come into contact with each other, and performing compression molding. (11) The method for producing a semiconductor chip sealing body according to (10), wherein the molding resin is in the form of granules. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a release film for a semiconductor mold that is less likely to leave peeling residue and that further suppresses film breakage, a method for producing a semiconductor chip encapsulated body, and a semiconductor. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of the face-up compression molding process for manufacturing FO-WLP. DETAILED DESCRIPTION OF THE INVENTION

[0012] The release film for a semiconductor mold in the present invention (hereinafter sometimes simply referred to as a release film) comprises a release layer and a polyester resin layer, and the release layer is a resin layer present on at least one surface, and on that surface, the water contact angle measured by the method described below is 85° or more.

[0013] <Composition and Structure of Polyester Resin Layer> The polyester resin layer in the present invention contains a polyester resin as a main component, which means that the polyester resin accounts for more than 70% by mass of the components constituting the film.

[0014] Polyester resins can be obtained by 1) polycondensation of dicarboxylic acids or their ester-forming derivatives (hereinafter collectively referred to as "dicarboxylic acid components") and diol components or their ester-forming derivatives (hereinafter collectively referred to as "diol components"), 2) polycondensation of compounds having carboxylic acids or carboxylic acid derivatives and hydroxyl groups in one molecule, and a combination of 1) and 2).

[0015] In 1), examples of the dicarboxylic acid component include aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, dimer acid, eicosanedioic 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, 1,4-naphthalenedicarboxylic acid, and 1,5-naphthalenedicarboxylic acid; Representative examples of aromatic dicarboxylic acids include dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 5-sodiumsulfoisophthalic acid, phenylendanedicarboxylic acid, anthracenedicarboxylic acid, phenanthrenedicarboxylic acid, and 9,9'-bis(4-carboxyphenyl)fluorene acid, or ester derivatives thereof. These may be used alone or in combination.

[0016] Also usable are dicarboxy compounds in which hydroxy acids such as l-lactide, d-lactide, hydroxybenzoic acid, and their derivatives, or a combination of multiple hydroxy acids, etc., are condensed to at least one carboxy terminal of the above-mentioned dicarboxylic acid component.

[0017] 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. These may be used alone or in combination as needed. Dihydroxy compounds formed by condensing diols with at least one hydroxyl terminal of the above-mentioned diol components may also be used.

[0018] On the other hand, in 2), examples of compounds having a carboxylic acid or a carboxylic acid derivative and a hydroxyl group in one molecule include oxyacids such as l-lactide, d-lactide, and hydroxybenzoic acid, as well as their derivatives, oligomers of oxyacids, and dicarboxylic acids condensed with one of the carboxyl groups of a oxyacid.

[0019] Specific examples of polyester resins include homopolymers such as polyethylene terephthalate, polyethylene-2,6-naphthalate, polypropylene terephthalate, polybutylene terephthalate, and polylactic acid, as well as copolymers thereof. The polyester resin constituting the polyester film of the present invention may be one selected from the above-mentioned homopolymers and copolymers, or may be a blend of homopolymers or a blend of a homopolymer and a copolymer.

[0020] Here, as the homopolymer of the polyester resin, it is preferable to use any one of polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, and polylactic acid from the viewpoint of film-forming properties, and among these, it is more preferable to use any one of polyethylene terephthalate and polyethylene-2,6-naphthalate from the viewpoint of ease of processability, and it is particularly preferable to use polyethylene terephthalate from the viewpoint of design properties.

[0021] Furthermore, a polyester resin copolymer refers to a polymer in which less than 50 mol% of the entire polyester resin is composed of either or both of different dicarboxylic acid components and diol components. When blending with a homopolymer, it is preferable to use a copolymer in which 50 mol% or more of the entire polyester resin contains the same molecular structure as the target homopolymer.

[0022] Here, as the polyester resin copolymer, from the viewpoint of excellent polymerization suitability, thermal stability, and compatibility with homopolymers, those containing alicyclic dicarboxylic acids, isophthalic acid, or naphthalenedicarboxylic acid as the dicarboxylic acid component and butanediol, ethylene glycol, spiroglycol, or cyclohexanedimethanol as the diol component are preferably used as copolymerization components, and these may be used alone or in combination as necessary. The inclusion of a copolymer component reduces the crystallinity of the film, making it easier for oligomers contained in the film to remain in the film bulk, and preventing them from precipitating on the film surface upon heating. By preventing oligomer precipitation on the film surface upon heating, for example, contamination of the molded resin surface and the mold surface opposite the molded resin can be more effectively prevented during compression molding.

[0023] In the polyester resin constituting the base layer of the release film of the present invention, the amount of isophthalic acid residues relative to the dicarboxylic acid component is preferably 0.5 mol% or more, since this improves the formability of the release film. Furthermore, the amount of isophthalic acid residues is preferably 10 mol% or less, since this suppresses a decrease in transfer efficiency of unevenness due to excessive softening and enhances designability. From the same viewpoint, the amount of isophthalic acid residues is preferably 1.0 mol% or more and 7.0 mol% or less, and even more preferably 1.5 mol% or more and 3.0 mol% or less. Furthermore, from the viewpoint of expecting the same effect, the amount of cyclohexanedimethanol residues or butylene glycol residues relative to the diol component is preferably 0.5 mol% or more and 20 mol% or less, more preferably 5.0 mol% or more and 17 mol% or less, and even more preferably 8.0 mol% or more and 15 mol% or less.

[0024] In order to improve moldability, it is preferable to contain a polyalkylene glycol component as a softening component in the polyester resin. As the polyalkylene glycol component, polyethylene glycol, polypropylene glycol, or polybutylene glycol is preferably used, and polyethylene glycol is more preferably used because of its high decomposition temperature and ease of melt-kneading with the polyester resin as a solid.

[0025] The polyalkylene glycol component content is preferably 0.1% by mass or more relative to 100% by mass of the polyester resin layer, as this further improves moldability. Furthermore, the polyalkylene glycol component content is preferably 3.0% by mass or less relative to 100% by mass of the polyester resin layer, as this suppresses poor mold releasability due to thermal decomposition of the polyalkylene glycol component. From the same perspective, the polyalkylene glycol component content is more preferably 0.3% by mass or more and 2.0% by mass or less, and even more preferably 0.5% by mass or more and 1.0% by mass or less, relative to 100% by mass of the polyester resin layer. However, if the content of the polyalkylene glycol component in the polyester resin is 0.5% by mass or more, the polyester resin may become too flexible, resulting in film tearing after molding.

[0026] The amount of the copolymerized component residues and the amount of the added components were measured by solvent extraction of the release film and then proton nuclear magnetic resonance spectroscopy ( 1 H-NMR) and carbon nuclear magnetic resonance spectroscopy ( 13 The analysis can be carried out by known techniques such as C-NMR.

[0027] In the present invention, the polyester resin layer is a laminate of two or more layers having at least a polyester resin A layer and a polyester resin B layer. The inorganic particle content of the polyester resin A layer is preferably 5% by mass or more and 19% by mass or less, and the inorganic particle content of the polyester resin B layer is preferably less than 5% by mass. This configuration facilitates maintaining film-forming stability and moldability even in a film containing a high concentration of particles due to the presence of the polyester resin B layer, which has a low inorganic particle content. Therefore, the particle content of the polyester resin B layer is preferably less than 5% by mass, and more preferably 0% by mass or more and 3% by mass or less. Considering film-forming stability alone, the most preferred embodiment is one in which no particles are added to the B layer. From the perspective of imparting design, the laminate preferably has a structure in the order of at least a release layer / A layer / B layer. As long as the structure is as described above, it may have a three-layer structure of A layer / B layer / A layer, in which the A layer is laminated on both sides of the B layer, or a structure in which 3 to 10,000 layers are alternately laminated. It is preferable that an A layer is also formed on the back side opposite the release layer side (such as a release layer / A layer / B layer / A layer configuration), because this allows for good air release when the release film and the mold are adsorbed and fixed by vacuuming, thereby preventing wrinkles from occurring. When there are two or more polyester resin A layers, it is preferable that at least one of them satisfies this aspect, and it is more preferable that all of the multiple A layers satisfy this aspect.

[0028] The lamination ratio of Layer A to Layer B is not limited, but if film-forming stability and formability are important, a higher ratio of Layer B is preferable, while if designability and air release are important, a higher ratio of Layer A is preferable. For example, the thickness-wise lamination ratio of Layer A to Layer B may be 1:1 to 1:40, and from the viewpoint of film-forming stability and designability, a ratio of 1:5 to 1:20 is preferable. The absolute thickness of Layer A is preferably 1 μm or more from the viewpoint of designability and air release, and is preferably less than 20 μm from the viewpoint of film-forming stability.

[0029] The thickness of the release film for a semiconductor mold in the present invention is preferably 39 μm or more and 100 μm or less, more preferably 39 μm or more and 75 μm or less, from the viewpoints of suppressing film breakage during molding and vacuum suction properties during molding.

[0030] In the release film of the present invention, it is preferable to set the average particle size of the particles contained in the polyester resin layer to 0.10 μm or more, since this further enhances the shape-imparting effect of the particles. Furthermore, it is preferable to set the average particle size of the particles contained in the polyester resin layer to 15 μm or less, since this suppresses deterioration of releasability and moldability due to uneven surface irregularities. From the same viewpoint, the average particle size of the particles contained in the polyester resin layer is more preferably 1.0 μm or more and 10 μm or less, and even more preferably 2.0 μm or more and 6.0 μm or less. The average particle size is determined by the method described below.

[0031] Furthermore, by setting the specific gravity of the particles contained in the polyester resin layer to 1.5 or more, it is possible to incorporate the particles in the resin layer at a high concentration, which is preferable because it enhances the design. Furthermore, by setting the specific gravity of the particles to 5.5 or less, it is possible to impart a more densely textured shape, which is preferable because it prevents deterioration in moldability and releasability. From the same perspective, the specific gravity of the particles contained in the polyester resin layer is more preferably 1.7 or more and 4.5 or less, and even more preferably 2.0 or more and 3.5 or less.

[0032] The particle specific gravity can be determined by a known method, for example, by heating a precisely weighed release film in an electric furnace to decompose the organic matter and then weighing the ash content, or by decomposing and liquefying the resin component of the release film with an alkaline solution or dissolving it in a solvent such as hexafluoro-2-propanol or o-chlorophenol, separating and washing the particle component, and then weighing and measuring the particle content.

[0033] Specific examples of inorganic particles used in the release film for semiconductor molds in the present invention include metals such as gold, silver, copper, platinum, palladium, rhenium, vanadium, osmium, cobalt, iron, zinc, ruthenium, praseodymium, chromium, nickel, aluminum, tin, zinc, titanium, tantalum, zirconium, antimony, indium, yttrium, and lanthanum; metal oxides such as zinc oxide, titanium oxide, cesium oxide, antimony oxide, tin oxide, indium tin oxide, yttrium oxide, lanthanum 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 zeolite; and carbon-based materials such as talc and kaolin, carbon black, fullerene, chopped or milled carbon fiber, and carbon nanotubes.

[0034] <Method of manufacturing polyester resin layer> The polyester resin layer of the release film of the present invention is preferably a biaxially oriented film from the viewpoint of generating a surface irregularity shape using inorganic particles. If particles are incorporated into an unstretched sheet, the particles may become embedded inside during film formation, resulting in insufficient design. Here, a biaxially oriented film can be obtained by stretching an unstretched film obtained by any conventionally known method, either in the longitudinal direction and then in the width direction, or in the width direction and then in the longitudinal direction, using a sequential biaxial stretching method, or by a simultaneous biaxial stretching method in which the film is stretched in the longitudinal and width directions almost simultaneously. The state of biaxial orientation achieved by biaxial stretching is determined by the method described in Evaluation Method (21) of the Invention, Determining the State of Biaxial Orientation by Laser Raman Spectroscopy.

[0035] In this stretching method, the stretching ratio in the longitudinal direction is preferably 2.7 to 3.6 times, more preferably 3.0 to 3.4 times. The stretching temperature in the longitudinal direction is preferably 70°C to 90°C. The stretching ratio in the width direction is preferably 3.0 to 5.0 times, more preferably 3.2 to 4.0 times. In the present invention, the machine direction (MD) is defined as the longitudinal direction, and the direction perpendicular to the longitudinal direction is defined as the width direction (TD). However, if the longitudinal and width directions of the film are unknown, the breaking strength is measured in any one direction (0°) of the film and in directions at 15°, 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135°, 150°, and 165° from that direction. The direction with the highest breaking strength is considered to be the width direction, and the direction perpendicular to the width direction is considered to be the longitudinal direction.

[0036] Furthermore, the film is heat-treated after biaxial stretching. Heat treatment can be carried out by any conventionally known method, such as in an oven. This heat treatment is preferably carried out in an atmosphere at a temperature of at least -40°C below the crystalline melting peak temperature (Tm) of the film and at most Tm - 5°C. By setting the heat treatment temperature at Tm - 40°C or higher, stretching stress can be sufficiently relaxed, improving formability during compression molding. Furthermore, by setting the heat treatment temperature at Tm - 5°C or lower, embedding of particles near the surface of the polyester resin layer can be suppressed, improving designability. From the same viewpoint, the heat treatment temperature is more preferably at least Tm - 30°C and at most Tm - 8°C, and even more preferably at least Tm - 20°C and at most Tm - 10°C.

[0037] The heat treatment time can be set to any value within a range that does not deteriorate the properties, but a time of 5 to 60 seconds is preferred because it can enhance the effects of the heat treatment temperature described above. From the same viewpoint, the heat treatment time is more preferably 7 to 40 seconds, and even more preferably 10 to 25 seconds.

[0038] <Composition and structure of release layer> The release layer in the present invention preferably contains a binder resin, because this improves adhesion to the polyester resin layer and also enables adjustment of the peel strength from the object to be released. Specific examples of the binder resin include polyester resin, polystyrene resin, acrylic resin, urethane resin, polyvinyl, polyalkylene glycol, polyalkyleneimine, cellulose, starch, etc., and acrylic resin is preferably used from the viewpoint of improving moldability and releasability.

[0039] Examples of the acrylic resin include a homopolymer or copolymer of a (meth)acrylic acid alkyl ester, and a (meth)acrylic acid ester copolymer having a curable functional group on the side chain and / or main chain end, and examples of the curable functional group include a hydroxyl group, a carboxyl group, an epoxy group, an amino group, etc. Among these, an acrylic monomer copolymer in which an acrylic monomer and an acrylic acid ester having a curable functional group on the side chain and / or main chain end are copolymerized is preferred.

[0040] Furthermore, it is preferable to add a crosslinking agent as a component constituting the release layer. The use of various crosslinking agents in combination with the aforementioned resins can dramatically improve heat resistance. The crosslinking agent is preferably one or more selected from oxazoline resins, melamine resins, epoxy resins, carbodiimide resins, and isocyanate resins. From the viewpoint of the solvent resistance of the release layer, melamine resins are more preferably used. Crosslinking agents can be mixed in any ratio, but from the viewpoint of improving release properties, it is preferable to add 5 to 50 parts by mass of crosslinking agent per 100 parts by mass of binder resin, more preferably 10 to 40 parts by mass. Adding less than 5 parts by mass of crosslinking agent can result in insufficient release properties and scratches during roll transport. Adding more than 50 parts by mass can easily cause unevenness during application, resulting in reduced release properties, which may be undesirable.

[0041] In the present invention, the resin composition forming the release layer preferably contains, in addition to the binder resin and crosslinking agent, an additive for the purpose of imparting releasability. The additive is preferably 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 using an additive mass of 3 parts by mass or more, releasability can be imparted, and by using an additive mass of 50 parts by mass or less, it is possible to impart heat resistance to the release layer that can withstand compression molding, thereby suppressing a decrease in releasability. The additive mass is preferably 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.

[0042] The additives referred to in the present invention refer to compounds that impart mold-releasing properties to the surface of a resin when added to the resin. Specific 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 chain-containing compounds are preferred from the viewpoint of mold-releasing properties and suppressing poor appearance. The long-chain alkyl compound referred to in the present invention 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 compounds having a long-chain alkyl group in the side chain of the main chain polymer.

[0043] In compounds having a long-chain alkyl group in the side chain of the main chain polymer, examples of the main chain polymer include acrylate polymers or copolymers, polyvinyl alcohol (including partially saponified polyvinyl acetate), ethylene-vinyl alcohol copolymers (including partially saponified ethylene-vinyl acetate copolymers), vinyl alcohol-acrylic acid copolymers (including partially saponified vinyl acetate-acrylic acid copolymers), polyethylimine, polyvinylamine, styrene-maleic anhydride copolymers, and polyurethanes.

[0044] <Method for forming release layer> A preferred embodiment of the release film for a semiconductor mold of the present invention is characterized in that a release layer is provided on one or both sides of the polyester resin layer.

[0045] Providing a release layer on only one side of the polyester resin layer is preferable because it shortens the manufacturing process of the release layer. When the surface composition or properties of the polyester resin layers are different, providing a release layer on the side with the lower 60° gloss in the surface gloss measurement described below and arranging it on the surface that comes into contact with the mold resin during molding can achieve both excellent releasability and design. Providing release layers on both sides of the polyester resin layer is also preferable because it imparts releasability to the mold side and prevents precipitated oligomers and the like from adhering to the mold. Similarly, in this case, it is more preferable to arrange the side with the lower 60° gloss on the surface that comes into contact with the resin during molding.

[0046] As a method for providing a release layer on a polyester resin layer, the resin composition of the release layer is dissolved or dispersed in a solvent, and then coated on the polyester resin layer, and the solvent is dried and heated after coating; the resin composition of the release layer is melt-extruded together with the polyester resin layer, and then formed into a sheet together with the polyester resin layer by the above-mentioned method; the resin composition of the release layer is extruded molten on a polyester resin layer that has been subjected to corona treatment or the like to provide a resin layer; and the polyester resin layer and the release layer are laminated together, which are separately produced.Among these, the method of providing a release layer by coating is preferred, from the viewpoint of being able to freely select the preferred binder resin, additives, and crosslinking agent.

[0047] A preferred method for applying a release layer to a polyester resin layer is to uniformly apply the layer using a metaling bar or gravure roll, followed by drying in an oven. When applying using a coating method such as gravure coating, it is preferable to apply the layer in a manner that does not inhibit the flow and leveling of the coating layer. The oven temperature is preferably 70 to 245°C, more preferably 80 to 235°C, and most preferably 90 to 225°C. If the drying temperature is lower than 70°C, the release layer may not cure sufficiently, resulting in poor adhesion between the polyester resin layer and the release layer. Furthermore, if the temperature is higher than 245°C, thermal deformation of the film may result in a decrease in coating thickness accuracy. The heat treatment time is preferably 1 to 60 seconds, more preferably 5 to 40 seconds, and most preferably 10 to 30 seconds.

[0048] In the semiconductor mold release film of the present invention, in order to ensure stable releasability, the release layer can also be provided by in-line coating. Specifically, in the production process of the polyester resin layer, a resin composition of the release layer is dissolved or dispersed on a film that has been at least uniaxially stretched, and the resin composition is uniformly applied using a metaling bar or gravure roll, and the coating material is dried while stretching. By using this method, the thickness of the release layer can be made more uniform. In addition, by increasing the molecular affinity with the polyester resin layer, the adhesion between the polyester resin layer and the release layer can be improved, and by heat treatment at a higher temperature than offline coating, the degree of hardening of the coating film is increased, improving heat resistance and chemical resistance, and at the same time, there is the advantage that aging treatment after production is unnecessary or can be shortened.

[0049] In the release film for semiconductor molds of the present invention, the thickness of the release layer after drying is preferably 10 nm or more, since the release layer can maintain its conformity to the surface shape of the polyester resin layer even when subjected to high pressure such as compression molding. Furthermore, the thickness of the release layer after drying is preferably 2000 nm or less, since this enhances the design without damaging the uneven shape of the polyester resin layer. From the same viewpoint, the thickness of the release layer after drying is preferably 50 nm or more and 1500 nm or less, and more preferably 100 nm or more and 1200 nm or less.

[0050] Similarly, if particles are contained in the release layer, this may result in a decrease in release properties due to unevenness and may cause process contamination due to particle shedding. It is preferable that the particle content in the release layer is 4% by mass or less per 100% by mass of the layer, since this allows for both release properties and moldability to be achieved without impairing the effects of the surface shape of the polyester resin layer. The particle content in the release layer is more preferably 1% by mass or less, and even more preferably, no particles are contained.

[0051] The release surface of the release film for a semiconductor mold in the present invention preferably has a water contact angle of 85° or more, since this improves releasability. Furthermore, a water contact angle of 120° or less is preferred, since this improves the conformability of the mold resin and enhances design. From the same viewpoint, the water contact angle is more preferably 90° or more and 115° or less, and even more preferably 95° or more and 110° or less.

[0052] <Film characteristics> A preferred embodiment of the release film for a semiconductor mold of the present invention has a film rigidity of 5.0 N·mm·10 at 175°C in either the longitudinal direction or the width direction. -3 More than 20N mm 10 -3 This range ensures good formability and prevents film tearing after compression molding at 175°C. To provide the film with compression molding formability, the film stiffness must be 20 N·mm·10 -3The lower the better, but from the viewpoint of suppressing film breakage after molding, it is preferable that the film stiffness at 175°C in either the longitudinal direction or the width direction is 5.0 N·mm·10 -3 More than 8.0N·mm·10 is preferable. -3 More preferably, it is 10N·mm·10 -3 From the same viewpoint, it is more preferable that the release film for a semiconductor mold of the present invention has a film rigidity of 5.0 N·mm·10 at 175°C in the longitudinal direction and the width direction. -3 More than 20N mm 10 -3 It is preferable that the load is less than 8.0 N·mm·10 -3 More than 20N·mm·10 -3 It is more preferable that it is 10 N·mm·10 -3 More than 20N·mm·10 -3 It is more preferable that the film stiffness at 175°C is determined by the method described below.

[0053] In addition, from the viewpoint of suppressing peeling residue, the release film for a semiconductor mold of the present invention has a film rigidity of 5.0 N·mm·10 at 175°C in either the longitudinal direction or the width direction. -3 More than 20N mm 10 -3 It is preferable that the film stiffness is 5.0 N·mm·10 -3 This suppresses peel residue caused by cohesive failure of the film, and -3 By satisfying the condition below, localized uneven pressure can be avoided and peeling residue can be suppressed.

[0054] Film stiffness at 175°C is 5.0 N·mm·10 -3 To achieve this, the raw material composition must have a copolymerization component content of at least 15 mol% in the polyester resin, be stretched by biaxial stretching to an areal ratio of 10 times or more, and have a film thickness of 39 μm or more after biaxial stretching.

[0055] Furthermore, even if the amount of copolymerization components in the polyester resin is 15 mol% or less, film tearing may occur if low-molecular-weight components, etc., are contained in an amount of 0.5 mass% or more. Therefore, the release film for semiconductor molding in the present invention preferably has a low-molecular-weight component content of less than 0.5 mass%. Here, low-molecular-weight components refer to organic substances with a molecular weight of 2000 or less. Examples of such low-molecular-weight components include polyalkylene glycol components, and among these, polyalkylene glycol components refer to polyethylene glycol, polypropylene glycol, and polybutylene glycol. Previous inventions have focused on mixing flexible resins such as plasticizers to impart processability during molding. However, when using full molding, the latest packaging technology, film tearing must be considered. The optimal film stiffness for this process is 5.0 N·mm·10. -3 More than 20N mm 10 -3 The present inventors have clarified that the following facts have led to the present invention. Furthermore, film breakage after compression molding also depends on the particle content of the polyester resin layer. Regardless of the particle concentration of the entire film, if the polyester resin layer has a particle content of 18% by mass or more, film breakage may occur due to the presence of a high-concentration particle resin layer. The lower the particle content, the more effectively film breakage can be suppressed. Therefore, in order to suppress film breakage, it is necessary to maintain the film stiffness at 175°C at 5.0 N·mm·10 -3 In addition to the above, it is preferable that the resin layer does not contain low-molecular-weight components and has a particle content of 18% by mass or less. The inventors have found that the content of the low-molecular-weight components has a relatively small effect on the amount of oligomer extraction and process contamination, while the void content and crystallinity have a greater effect.

[0056] The release film for a semiconductor mold according to the present invention preferably has a breaking stress at 175°C of 20 MPa or more and 100 MPa or less in both the longitudinal and width directions. A breaking stress of 20 MPa or more at 175°C can increase the rigidity of the film, thereby further enhancing the effect of suppressing film breakage. Furthermore, a breaking stress of 100 MPa or less at 175°C is preferable because it can improve the vacuum suction properties during molding. From the same viewpoint, the breaking stress at 175°C is more preferably 60 MPa or less, and most preferably 40 MPa or less, in both the longitudinal and width directions.

[0057] The breaking stress at 175°C can be adjusted by including copolymerization components in the resin that makes up the polyester resin layer. For example, copolymerizing isophthalic acid or cyclohexanedimethanol components with the homopolyester polyethylene terephthalate promotes amorphization (suppression of orientation), thereby lowering the breaking stress. The particle content of the entire film, the particle content of the particle-containing layer, and the lamination ratio of each layer also contribute to the breaking stress. For example, the higher the particle content in the film, the greater the likelihood of particle-based breakage, resulting in a lower breaking stress. On the other hand, if the film contains a polyester resin layer with a high particle content, even if the particle content is low overall, the breaking stress may be lower. Furthermore, in films composed only of homopolyester and particles, the biaxial stretching process significantly increases the degree of orientation crystallization, making it difficult to achieve a breaking stress of 60 MPa or less at 175°C.

[0058] In a preferred embodiment of the release film for a semiconductor mold of the present invention, the number of protrusions having a height of 1 μm or more on at least one of the outermost layers is 500 / mm 2 More than 8000 pieces / mm 2 The number of protrusions with a height of 1 μm or more on the release film is 500 / mm 2 By having these surface protrusions, it is possible to transfer fine irregularities to the surface of the molded resin, which improves the processing accuracy of marking the surface of the molded resin during the subsequent processing step of laser irradiation. 2If the number of projections is less than 8000, the design may be inferior and the marking accuracy may be reduced. 2 In order to exceed this limit, a large amount of particles must be contained, which may result in poor film formation stability. Even if the particle content of the entire film is less than 19%, a film having a resin layer with a particle content of more than 19% or a film having a number of protrusions with a height of 1 μm or more of 8,000 / mm 2 If the pressure exceeds this limit, particles or protrusions may cause film tearing after compression molding.

[0059] By keeping the thickness in this range, excellent design can be achieved during compression molding. From the viewpoint of design, the number of protrusions having a height of 1 μm or more on at least one of the outermost layers is more preferably 1000 / mm 2 More than 7000 pieces / mm 2 2000 pieces / mm or less 2 More than 6000 pieces / mm 2 It is most preferable that the number of protrusions is 500 / mm or less. The number of protrusions is determined by the method described below. 2 More than 8000 pieces / mm 2 The number of protrusions with a height of 1 μm or more is 500 / mm 2 More than 8000 pieces / mm 2 The number of protrusions with a height of 1 μm or more is 500 / mm or less, resulting in a finer uneven shape, which is excellent in design and improves marking accuracy. 2To achieve a height of 1 μm or more, a method of including a large number of inorganic particles having a height of 1 μm or more can be mentioned. Note that, due to the mechanism by which inorganic particles contained in polyester resins form irregularities on the surface layer through biaxial stretching, it is difficult to efficiently form protrusions of 1 μm in height with a particle size of 1 μm. Therefore, it is preferable to include a large number of inorganic particles having an average particle size of 1.5 μm or more, and the release film for semiconductor molds of the present invention preferably includes a polyester resin layer having an inorganic particle content of 10% by mass or more but less than 18% by mass. From the same perspective, the average particle size of the inorganic particles in the polyester resin layer is preferably 2.0 μm or more but less than 8.0 μm. Note that, from the viewpoints of design transfer efficiency and suppression of peeling residues during mold release, it is preferable that the thickness of each polyester resin A layer be 0.5 to 2 times the average particle size of the inorganic particles. Furthermore, when the polyester resin layer is constructed as a single layer, even if the film is thick and the inorganic particle content is less than 10% by mass, the number of protrusions of 1 μm or more in height can be 500 / mm. 2 Although it is possible to achieve a thickness of 1 μm or more, particle-induced film tearing during film production, which can reduce productivity, is preferable. Therefore, a laminate structure consisting of a polyester resin layer A containing a high concentration of particles and a polyester resin layer B containing as few particles as possible is preferred. Furthermore, the number of protrusions 1 μm or more in height is not simply determined by the particle size and amount added. The resin composition of the polyester resin layer plays a major role. For example, biaxial stretching of a film containing particles can result in the formation of voids originating from the particles. Even with the same particle addition amount, the formation of voids tends to flatten the surface irregularities due to the voids, resulting in a decrease in the number of protrusions 1 μm or more in height. On the other hand, the absence of voids results in a relatively high number of protrusions 1 μm or more in height. Therefore, for the purpose of efficiently imparting design features, a low void content (Vz) in the polyester resin is preferable; ultimately, a void-free state is ideal. Furthermore, the formation of voids tends to lower the Young's modulus and breaking stress of the film.

[0060] In the present invention, the 60° gloss measured from the release layer side is preferably 1% or more and 20% or less. In the present invention, from the viewpoint of design, the lower the surface gloss of the molding resin after the release film is peeled off, the more preferable it is. Since the design is achieved by transferring the surface shape of the release film in an inverted manner, the lower the gloss of the release film, the lower the gloss of the molding resin to which the inverted shape is transferred. Therefore, the 60° gloss measured from the release layer side is preferably 1% or more and 20% or less. To achieve a 60° gloss measured from the release layer side of 1% or more and 20% or less, a preferred control method is to include particles having an average particle size of 1 μm or more in the polyester resin A layer (e.g., polyester resin A layer) that transfers the irregularities to the molding resin, in an amount of 10% by mass or more. As mentioned above, if the resin layer contains a particle content of 18% by mass or more, film tearing may occur after molding.

[0061] The release film for semiconductor molds of the present invention preferably has a cushioning ratio of 60% or more and less than 88% from the viewpoint of suppressing peeling residues caused by the film during mold release. The cushioning ratio is determined by the method described below, and a higher cushioning ratio indicates lower cushioning (harder). The cushioning ratio can be controlled by the void content, described below. As described above, the conventional design concept is to efficiently transfer texture to the mold resin by minimizing voids in the polyester resin layer. However, in the present invention, high cushioning during compression molding suppresses unevenness in contact with the mold surface, and localized pressure unevenness is avoided by applying pressure evenly to the film. This has led to the achievement of suppressing peeling residues caused by cohesive failure of the polyester resin A layer, which has a high particle content and is the cause of peeling residues. Because film peeling residues on the mold resin can cause defects in precision semiconductors, it is important to suppress peeling residues as much as possible. For this reason, when texture transfer is performed by incorporating particles into the polyester resin layer, it is preferable to suppress peeling residues caused by the film. For this reason, it is preferable to set the cushioning ratio in the range of 60% or more and less than 88%. From the viewpoint of further expecting the same effect, a cushion ratio of 60% or more and 70% or less is more preferable. A cushion ratio of 88% or more is excellent in efficient transfer of the design, but peeling residue of the film may remain on the mold resin side when the film is released. Furthermore, a cushion ratio of less than 60% may reduce the transfer efficiency of the design.

[0062] In the semiconductor mold release film of the present invention, it is preferable that the void content Va of the polyester resin A layer be 10% to 30% and the void content Vz of the entire film be 2% to 10% from the viewpoint of the cushioning properties of the film and reducing the amount of oligomer extraction due to heating. The void content of each layer is determined by the method described below. Void formation in the polyester resin layer occurs by biaxial stretching while containing particles. Therefore, the void content is influenced by the particle concentration and the affinity of the particles for the polyester resin. For example, silica-based particles have a high affinity with polyester resin and are less likely to form voids even when biaxially stretched. Therefore, particles with a low affinity for polyester resin and a large average particle size are more likely to form voids efficiently. Furthermore, voids are more easily formed by setting the film stretching temperature in the biaxial stretching process lower than the glass transition temperature of the resin constituting the polyester resin layer or by heat treatment at a temperature lower than the melting point of the resin constituting the polyester resin layer. Furthermore, to achieve a void content Va of 10% to 30% in the polyester resin A layer, a preferred control method is to use only homopolyester and inorganic particles. For example, the polyester resin A layer can be formed using only polyethylene terephthalate and silica particles. When a copolymerization component is included, the melting point of the polyester resin A layer drops, and the formed voids tend to disappear during heat treatment after biaxial stretching, reducing the void formation efficiency. While lowering the heat treatment temperature may prevent void disappearance, this can lead to deterioration in dimensional stability and the transfer of wrinkles due to the deterioration in dimensional stability during molding. Taking all factors into consideration, a polyester resin A layer containing only homopolyester and inorganic particles is preferred to achieve a void content Va of 10% to 30% in the polyester resin A layer. The type and concentration of inorganic particles can be appropriately selected depending on other required properties. Furthermore, even if the film is heated with voids formed, oligomers contained in the film bulk are trapped in the voids and are less likely to reach the surface, thereby reducing the amount of oligomer extraction due to heating. Therefore, the greater the void content of the entire film, the more the amount of oligomer extraction can be reduced.

[0063] The release film for a semiconductor mold in the present invention has a density of 1.10 g / cm 3 More than 1.34g / cm 3 It is preferable that the density is not more than 1.40 g / cm. In the case of a normal biaxially oriented polyethylene terephthalate film, the density is about 1.40 g / cm. 3 Similar to the effect of void content, the film density is 1.34 g / cm 3 If the density is 1.10 g / cm or less, uniform pressure can be applied during molding, and the effect of suppressing peeling residue can be further improved. 3 More than 1.34g / cm 3 To achieve this, it is preferable to suppress the orientation crystallization of the film and to set the void content Vz of the film to 2% or more. The density is determined by the method described below.

[0064] The release film for semiconductor molds in the present invention preferably has an optical density of 0.1 or more and 2.0 or less. The optical density in this range makes it easy to see and helps prevent forgetting to release the film after molding. In order to set the optical density in the range of 0.1 or more and 2.0 or less, a pigment such as titanium oxide may be added, or it is also a preferred embodiment that the void content Vz in the film is 2% or more.

[0065] The release film for semiconductor molds of the present invention has an oligomer extraction amount of 0 mg / m after heating at 185°C for 30 minutes. 2 More than 5.0mg / m 2 By suppressing oligomer precipitation on the film surface layer by heating, it is possible to prevent the molded resin surface and the mold surface opposite to the molded resin from being contaminated with oligomers, for example, when compression molding is performed. More preferably, it is 0 mg / m 2 More than 3.0mg / m 2 or less, more preferably 0 mg / m 2 More than 2.0mg / m 2 Below, particularly preferably 0 mg / m 2 More than 1.0mg / m 2The amount of oligomer extracted after heating at 185°C for 30 minutes is determined by the method described below.

[0066] The release film for semiconductor molds of the present invention preferably has a crystallinity of 3.0% or more and 21.0% or less. By setting the crystallinity within this range, oligomers contained in the film tend to remain in the film bulk, which is preferable because it prevents precipitation on the film surface upon heating. The crystallinity is more preferably 5.0% or more and 18.0% or less, and even more preferably 8.0% or more and 15.0% or less. To control the film crystallinity within this range, for example, a resin with low crystallinity can be used. For example, in the case of polyester, the crystallinity can be reduced by adding a copolymer component to the homopolyester. However, since the crystallinity of the film significantly affects dimensional stability, strength, etc., it is desirable not to deviate from the scope of the present invention. The crystallinity is determined by the method described below.

[0067] <Method of Manufacturing Semiconductor Chip Sealing Body> A method for producing a semiconductor chip encapsulated body using the release film for semiconductor molding of the present invention includes stacking the release film and a silicon wafer with a semiconductor chip arranged thereon in a molding device, placing a measured amount of molding resin on the wafer, and then transporting the release film of the present invention from above so that the release layer side faces the molding resin side and vacuum-adsorbing it, and performing compression pressing while heating the mold. That is, a preferred embodiment of the method for producing a semiconductor chip encapsulated body of the present invention is a method for producing a semiconductor chip encapsulated body that includes a step of placing the release film for semiconductor molding in a mold in a compression device so that the release layer and the molding resin contact each other, and performing compression molding. At this time, since the release film of the present invention is located between the molding resin and the mold, a design that provides excellent moldability and releasability is simultaneously required while forming a surface shape on the resin surface to impart design.

[0068] As described above, the release film of the present invention suppresses film breakage during compression molding while achieving both formability and releasability during compression molding, and its surface shape can impart a design suitable for compression molding. Furthermore, it is preferable for the molding resin to be granular from the viewpoint of improving formability and yield, and the release film of the present invention is particularly suitable for use because it can suppress film breakage. Furthermore, when a design is imparted to the molding resin, it is possible to improve the processing accuracy of laser irradiation and other processes in subsequent processing steps. Because these have the effect of suppressing processing defects due to the detachment of particle components, the release film of the present invention is suitable as a release film for circuit manufacturing processes and semiconductor manufacturing processes, and is particularly suitable for use as a release film for semiconductor encapsulation processes.

[0069] Furthermore, by using it in compression molding processing of semiconductor face-up methods, which have less resin flow during processing compared to face-down methods, the resin flow during processing can be improved, and wrinkles such as resin chipping can be suppressed. From this perspective, it can be suitably used in face-up methods.

[0070] However, as described above, when a polyester resin A layer is formed on the back side opposite the release layer side (e.g., a release layer / A layer / B layer / A layer configuration), it can be used preferably in a face-down method from the viewpoint of good air venting when the release film and mold are vacuum-attached and fixed. Furthermore, although the release film of the present invention has an uneven surface to impart design, its resin flowability during processing is good, preventing resin chipping and allowing the mold resin to extend wider than the semiconductor, enabling more accurate unevenness transfer. Therefore, it can be used preferably in a fan-out wafer-level packaging process among compression molding methods. For the same reason, it can be used preferably in a panel-level packaging method among fan-out wafer-level packaging.

[0071] [Methods for measuring and evaluating characteristics] (1) Polyester composition The film was dissolved in hexafluoroisopropanol (HFIP), 1 H-NMR and 13 The content of each monomer residue component is quantified using C-NMR. In the case of a laminated film, each layer of the film is scraped off depending on the laminate thickness to collect and evaluate the components that make up each layer.

[0072] (2) Cross-section observation of release film The film is embedded in epoxy resin, and two cross sections, one perpendicular to the thickness direction, are cut out using a known method (microtome or ion milling) appropriate for the type of particle. The cross sections are then observed using either a transmission electron microscope (Hitachi TEM H7100) or a scanning electron microscope (JEOL SEM JSM-6700F).

[0073] (2-1) Release film thickness, base film thickness, release layer thickness Using the above method, a magnification at which the release film thickness, base film thickness, and release layer thickness can be observed is selected, images of three different locations are obtained on cross sections in two directions, and the average value of a total of six points is calculated.

[0074] (2-2) Average particle size Using the above method, a magnification that can capture the particles in the polyester resin layer is selected, and images of three different locations are obtained on the cross section in two directions.Then, from the obtained images, an image analyzer is used to calculate the area-equivalent diameter per particle, and the average value of a total of six points is obtained.

[0075] (3) Film density The measurement sample is measured using a dry automatic density meter (AccuPycII 1345) manufactured by Micromeritics under the following conditions. Analysis gas: N2 Number of purges: 5 Purge fill pressure: 134.447kPaG (gauge pressure) Number of cycles: 5 Cycle fill pressure: 134.447kPaG (gauge pressure) ·End equilibration by: "Rate" "0.0345 psiG / min" (0.23788kPaG / min).

[0076] (4) Inorganic particle content in the film The measurement sample is dried under vacuum at 150°C for 24 hours and weighed. Next, it is dissolved in o-cresol / chloroform (mass ratio 7 / 3) at a temperature of 80°C, and then insoluble matter is separated using a centrifuge. The resulting insoluble matter is washed five times by adding the above solvent heated to a temperature of 80°C, and then dried under vacuum at 150°C for 24 hours and weighed. The content of insoluble matter relative to the sample before dissolution is taken as the content of inorganic particles in the film.

[0077] (5) Inorganic particle content in polyester resin layer A and polyester resin layer B The measurement sample, obtained by scraping out the polyester resin A layer, is dried under vacuum at 150°C for 24 hours and weighed. It is then dissolved in o-cresol / chloroform (7 / 3 by mass) at 80°C, after which the insoluble matter is separated using a centrifuge. The resulting insoluble matter is then washed five times with the solvent heated to 80°C. The sample is then dried under vacuum at 150°C for 24 hours and weighed. The inorganic particle content in the polyester resin A layer is determined by the same method as in the sample before dissolution.

[0078] (6) Number of protrusions with a height of 1 μm or more Using a scanning white light interference microscope, measurements are taken in 10 different fields of view. The sample is set so that the direction perpendicular to the X-axis of the sample stage (the Y-axis direction) is the longitudinal direction of the sample film (the longitudinal direction is the direction in which the film runs during the film manufacturing process), and measurements are taken under the following measurement conditions. After performing the following image processing on all obtained images using the accompanying analysis software (VS-Viewer), particle analysis is carried out for the entire field of view under the following conditions, and the number of protrusions 1 μm or higher in height from the reference plane (height zero) is determined and the average value is taken as the number of protrusions 1 μm or higher in height. <Device>: Hitachi High-Tech Science VS-1540 <Measurement conditions> Objective lens: 20x Wavelength filter: 530white Measuring device: Piezo Measurement mode: Wave Measurement field size: 283μm×283μm <Image processing conditions> Interpolation: Full Interpolation Filter: Median 3x3 Surface correction: 4th order <Particle analysis> Analysis: sudden analysis Image correction: None Height threshold: 1 μm Reference height: Zero plane. (Reference plane: Reference height = zero plane) The "zero plane" in the reference height setting is determined by observing the microscope image using the method described above, and then performing the image processing described above on the measurement image (113 μm × 113 μm) to determine the plane of the "average height (Ave)" automatically using the following formula (1).

[0079]

number

[0080] lx: Range length in the X direction in each measurement image after the image processing described above ly: Range length in the Y direction in each measurement image after the image processing described above ·h(x,y): Height at each image point (x,y) in the measurement image after the image processing described above.

[0081] (7) 60° gloss of release film According to the method specified in JIS-Z-8741 (1997), a Suga Test Instruments UGV-5D digital variable angle glossmeter is used to set the sample so that the release surface of the release film is the measurement surface, and the 60° specular gloss is measured with N=3, and the average value is taken as the 60° gloss. Similarly, the 60° gloss is also measured on the ND side of the polyester resin A layer.

[0082] (8) Young's modulus and breaking stress at 175°C The film was cut at a random position in the longitudinal direction (MD) into a rectangular sample measuring 150 mm long and 10 mm wide. Using a tensile tester (Orientec "Tensilon" (registered trademark) UCT-100) according to the method specified in JIS Z1702 (1994), a tensile test was performed in the longitudinal direction of the film with an initial tensile chuck distance of 50 mm and a tensile speed of 300 mm / min. The film sample was placed in a thermostatic chamber preheated to 175°C and preheated for 90 seconds before the tensile test was performed in air. Sampling was performed at five random positions, and the average of the measured values ​​was used for each sample. Similarly, the Young's modulus and breaking stress at 175°C in the transverse direction (TD) were also determined. In this invention, the machine direction (MD) is defined as the longitudinal direction, and the direction perpendicular to the longitudinal direction is defined as the transverse direction (TD). However, if the longitudinal and width directions of the film are unknown, the breaking strength 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, and the direction with the highest breaking strength is regarded as the width direction, and the direction perpendicular to the width direction is regarded as the longitudinal direction.

[0083] (9) Film stiffness at 175°C (8) Young's modulus at 175°C, Young's modulus obtained by the evaluation of breaking stress is E (N / mm 2), the measured width of the sample size is b (mm), and the thickness of the measurement sample obtained by method (2-1) is h (mm), and the value obtained from the following calculation formula (i) is the film rigidity at 175°C. Film stiffness at 175°C N·mm 2 10 -3 =(E×b×h 3 ) / 12···(i) (10) Cushioning rate (%) Using an Upright Dial Gauge manufactured by PEACOCK Ozaki Manufacturing Co., Ltd., the initial thickness of the release film is T0, the thickness when a load of 1 kg is applied is T1, and the thickness after the load is removed is T2. The thickness recovery rate is calculated using the following formula (ii). Formula (iii) is the thickness recovery rate. The cushioning rate and recovery rate are measured at 10 points on the release layer side of the film, and the average values ​​are used as the cushioning rate and thickness recovery rate of the film.

[0084] Cushioning rate (%) = T1 / T0 × 100 (ii) Thickness recovery rate (%) = T2 / T0 × 100···(iii).

[0085] (11) Void content Va (%) and void content Vz This is determined by the following steps (a1) to (a5). (a1) Using an ion milling device (IM4000 manufactured by Hitachi High-Tech Corporation), the film is cut perpendicular to the film surface while being cooled with liquid nitrogen to prevent deformation or damage to the film, and measurement samples are prepared. The cutting direction is rotated clockwise in 5° increments relative to the film surface, and a vertical cross section is prepared at each rotation angle until the total rotation angle reaches 90°, resulting in a total of 19 vertical cross-section samples. (a2) The prepared cross section was observed by the method described in (2) Cross-section observation of release film at a magnification of 1000 times and a measurement area of ​​1000 μm 2 If it is a single-layer structure, obtain scaled cross-sectional analysis data for the polyester resin layer, and if it is a composite structure, obtain scaled cross-sectional analysis data for each of the polyester resin A layer and polyester resin B layer. Before obtaining each cross-sectional analysis data, press AUTO CONTRAST. (a3) Image analysis software: ImageJ (National Institutes of Health open source) version 1.53k is used, and the cross-sectional analysis data is opened in ImageJ. Next, the image data is converted to 8 bits, and scale calibration is performed using the scaled cross-sectional analysis data obtained in (a2), and smoothing is performed. Next, Saturated pixels is set to 0.5%. After that, Black background is turned ON, the threshold is applied at Auto, and binarization is performed so that void areas become white. The area of ​​the areas that become white in Analyze Particles is taken as the void area, and in the case of a single-layer structure, the void area of ​​the polyester resin layer is calculated as St (μm 2 ), and if it is a composite structure, the void area of ​​the polyester resin A layer is Sa (μm 2 ), and the void area of ​​the polyester resin B layer is Sb (μm 2 ) (a4)Measurement area 1000μm 2 From the void area of ​​each layer obtained from the above, the void content of each layer is calculated as follows. Void content of polyester resin layer Vt (%) = St (μm 2 ) / 1000(μm 2 ) x 100 Void content of polyester resin A layer Va (%) = Sa (μm 2 ) / 1000(μm 2 ) x 100 Void content of polyester resin B layer Vb (%) = Sab μm 2 ) / 1000(μm 2 ) x 100 (a5) For all 19 vertical cross sections created in (a1), the void contents Vt, Va, and Vb are calculated using the procedures (a2) to (a4), and the value in the cutting direction of the sample with the highest void content Va is defined as the void content Va. The void contents Va and Vz are defined as follows: Void content Va: Polyester resin A layer measurement area 1000 μm 2 Void content V in Void content Vb: Polyester resin B layer measurement area 1000 μm 2 Void content V in Void content Vz: In the case of a single-layer structure, the polyester resin layer measurement area is 1000 μm 2 Void content V in When the polyester resin A layer and polyester resin B layer are combined, it is calculated using the following formula.

[0086] Vz = Σ [(void content of each layer) × (thickness of that layer / total film thickness)] The ion milling device, shape analysis laser microscope and its head unit, and analysis software may be replaced with alternatives that comply with equivalent standards.

[0087] (12) Optical density The optical density of the film is measured using an X-lite 361T tabletop black and white transmission densitometer. Measurements are taken at points 5 cm away from an arbitrary point on a straight line in the longitudinal and transverse directions of the film, and the arithmetic mean value of a total of nine measurements is taken as the optical density. If the directionality is unknown or there is no concept, measurements are taken on an arbitrary straight line and on a straight line perpendicular to it.

[0088] (13) Water contact angle After leaving the release film in an atmosphere of room temperature 23°C and relative humidity 65% ​​for 24 hours, the contact angle of pure water is measured at five points on the measurement surface held horizontally in the same atmosphere using a contact angle meter DM-501 (manufactured by Kyowa Interface Science Co., Ltd.), and the average value of the measured values ​​is taken as the contact angle of water.

[0089] (14) Crystal melting peak temperature Tm of the resin that constitutes the film 5 mg of sample is weighed on an electronic balance, placed in an aluminum sample pan, and measured using a Rigaku Corporation Thermo plus ECO2 series DSC Vesta, in accordance with JIS K7121 (1987) and JIS K7122 (1987), by raising the temperature from 25°C to 300°C at a rate of 20°C / min. Data analysis is performed using the same company's Thermo plus ECO2 system. The crystal melting peak temperature and crystal melting enthalpy of each peak are determined from the obtained DSC data. If multiple crystal melting peaks are observed, they are named Tm1, Tm2, ​​etc., in order of lowest peak temperature.

[0090] (15) Formability The evaluation is carried out using a 150mm square, 5mm deep concave mold and a vacuum forming machine (Seiko Sangyo Co., Ltd.: device name "300X"). Release film cut to A4 size is preheated with an infrared heater and then vacuum-sucked into a mold heated to 175°C, allowing it to conform to the mold. The vacuum is then released, and the depth at the corners of the removed release film is measured, with the average value for the four corners being taken as the mold depth. Based on the average value of the obtained mold depth and the reproducibility of the mold shape, conformability to the mold is evaluated as follows: A: The average molding depth is 4.8 mm or more, and the corners at the center of the mold recess on the bottom side of the mold are sharply molded. B: The average molding depth is 4.5 mm or more, and the corners on the bottom side of the mold are rounded, but molded. C: The average molding depth is less than 4.5 mm. A grade of B or above is considered a pass.

[0091] (16) Film tearing during molding Using a TOWA Corporation compression molding device LCM1010 (manual), film breakage after molding is judged under the following conditions: The release film is positioned so that the mold resin and the release surface of the release film are in contact. Molding resin: Sumitomo Bakelite (EME G311 Q Ver.GR) Molding resin amount: 19g (filled flat using a resin filling jig) Mold temperature: 175℃ Preheat time: 24 seconds Molding mode: Compression molding Forming load 1: 89.5kN (7MPa) Forming load 2: 89.5kN (7MPa) Cure time: 180 seconds Molding speed 7:0.5mm / sec Forming speed changeover 7-8: 195 mm Molding speed 8:0.5mm / sec Forming speed changeover 8-9: 195 mm Molding speed 9:0.5mm / sec Forming speed changeover 9-10: 195 mm Molding speed 10:0.5mm / sec Forming load switching 1-2: 600 sec Pressure position (position): 185mm Pressure position (%): 95%

[0092] Compression molding was performed under the above conditions, and after molding, the film was released from the molding resin. The released film was observed and the film breakage was evaluated as follows. A: There is no film tearing. B: There is one tear in the film, but the length of the tear is less than 3 mm. C: There is one tear in the film, but the length of the tear is less than 5 mm. D: There are two or more tears in the film. A grade of C or above is considered a pass.

[0093] (17) Mold releasability Using a vacuum press, a 2 mm thick mold resin (Nagase ChemteX Corporation: product name "R4212") is applied to the release layer surface of the release film and pressed under vacuum at a pressure of 2 MPa while being held at 125°C for 10 minutes. After leaving the film in an atmosphere at room temperature of 23°C and relative humidity of 65% for 24 hours, a peel test was performed on the release film at a peel angle of 90° and a peel speed of 300 mm / min. The peel force between the mold resin and the film was measured with N=3, the average value was calculated, and the results were evaluated according to the following criteria. A: Less than 3.0N / 25mm B:3.0N / 25mm or more A is a pass. Natural peeling is also an A. If the film breaks during peeling and it is difficult to measure the peel strength, an additional sample is prepared and the measurement is carried out once more. If it is still difficult to measure, the test is rated as B.

[0094] (18) Designability during compression molding Five molded samples are prepared using the method of (16), and the surface gloss of the molded resin after peeling off the release film is measured using a gloss meter (Suga Test Instruments Co., Ltd.: device name "Gloss Meter GM-1") for N=5, the average value is calculated, and the results are evaluated according to the following criteria. A: 60° glossiness is less than 10% B: 60° gloss is 10% or more and less than 20% C: 60° glossiness is 20% or more and less than 30% D: 60° glossiness is 30% or more A grade of C or above is considered a pass.

[0095] (19) Peeling residue caused by release film after compression molding A molded sample was prepared using method (16), and the molded resin surface after peeling off the release film was observed at 100x magnification using a Keyence microscope (VHX8000). Each white foreign object was counted as one piece of peeling residue, and the total peeling residue value for the nine fields of view was evaluated according to the following criteria. Each field of view was observed at a distance of at least 10mm. A: 0 to 10 residues from peeling caused by the release film are observed. B: 11 to 20 residues from peeling caused by the release film are observed. C: 21 to 30 peeling residues caused by the release film are observed. D: 31 or more peeling residues caused by the release film are observed. A grade of C or above is considered a pass.

[0096] (20) Vacuum suction during compression molding Using a compression molding machine (Apic Yamada Corporation: Machine name "WCM-300"), a mold resin (Nagase ChemteX Corporation: Product name "R4507") measured with a dispenser is dropped onto a 12-inch silicon dummy wafer so that it covers the dummy chips to a thickness of 1.5 mm, and the wafer is placed on the lower mold of the molding die. The mold temperature is set to 150°C, and the release surface of the release film is placed on the concave upper mold so that it is in contact with the mold resin, and then vacuum is applied to prevent wrinkles. At this time, the vacuum suction ability is evaluated based on the achieved vacuum level as follows. A: The vacuum level increased without any problems, and we were able to proceed to the next process and perform molding. B: The vacuum level did not increase, an error occurred, and the device stopped. A is a pass and B is a fail.

[0097] (21) Determination of biaxial alignment state by laser Raman spectroscopy The orientation parameters defined below are measured under the following conditions. The measurement sample is cut into cross sections in the longitudinal and width directions, and the orientation parameters for each direction are calculated by measurements from the cross-sectional direction. Cross-sectional measurements are performed on the front, center, and back sides, and the orientation distribution in the thickness direction is also confirmed. For measurements from the front side, the polarization angle is rotated in 15-degree increments to measure the angular distribution of orientation on the longitudinal and width directions. The orientation parameters for the longitudinal and width directions obtained from the cross-sectional measurements are used to convert the obtained scattering intensity into the orientation parameters for each direction. The orientation parameter is a unified standard across all directions and levels, and directly reflects the degree of orientation (it is not linear with respect to the degree of orientation). In the case of no orientation, the value is 1, and the higher the value, the more components are oriented in that direction. An orientation parameter of more than 2 is considered to be biaxially oriented. Device: T-64000 (Jobin Yvon / Atago Bussan) Conditions: Measurement mode; Microscopic Raman Objective lens: ×100 Beam diameter: 1 μm Light source; Ar+ Laser / 514.5nm Laser power: 60 mW Diffraction grating: Single 1800gr / mm Slit: 100 μm Detector: CCD / Jobin Yvon 1024×256 Intensity with polarization parallel to the longitudinal or transverse direction ((I 1615 ) parallel) and perpendicularly polarized light ((I 1615 The ratio of the perpendicular to the perpendicular is used as a parameter for evaluating the degree of orientation. Orientation parameter R=I 1615 Parallel / I 1615 vertical I 1615 Parallel: 1615cm with polarization parallel to the longitudinal and transverse directions -1 Raman band intensity I 1615 Vertical: 1615cm when polarized perpendicular to the longitudinal and width directions -1 Raman band intensity.

[0098] (22) Content of low molecular weight components in the film Measurements were performed using gel permeation chromatography (GPC). The instrument was a Tosoh HPLC 8120 series, with TSKgel SuperHM-H H4000 / H3000 / H2000 columns (7.8 mm diameter, 150 mm x 3), eluent THF (tetrahydrofuran), flow rate 1 mL / min, injection volume 20 μL, detector RI, measurement temperature 40 °C. The sample was dissolved in THF and then filtered through a 0.45 μm filter to remove additives such as silica. The resin components were measured. The column was stabilized in a heat chamber at 40 °C. THF was then passed through the column at this temperature at a flow rate of 1 mL / min. 50–200 μL of the resin THF sample solution, adjusted to a sample concentration of 0.05–0.6% by mass, was injected. When measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithm of the calibration curve created using several monodisperse polystyrene standard samples and the count number. From this, the area ratio (%) of peaks with molecular weights of less than 2000 to the total is calculated, and this value is taken as the content of low molecular weight components in the film.

[0099] (23) Oligomer extraction amount The film was heat-treated in an oven at 185°C for 30 minutes. After heat treatment, the measurement surface of the film was attached to the 50mm x 50mm x 30mm surface of a rectangular aluminum box, and the edges were folded along the box to secure it in place. The box was then immersed in dimethylformamide solvent to a depth of 5mm for 3 minutes, film-side down, to extract the surface-precipitated oligomer. Next, to prepare the standard solution, 11.2 mg of polyethylene terephthalate cyclic oligomer (trimer purity 89%) was placed in a 100mL volumetric flask and dissolved in 2mL of a 1,1,1,3,3,3-hexafluoro-2-propanol / chloroform mixed solvent (=1 / 1). This solution was then diluted to 100mL with chloroform to form the standard stock solution (trimer concentration 100µg / mL). This solution was serially diluted with dimethylformamide to prepare standard solutions with trimer concentrations of 10 μg / mL, 1 μg / mL, and 0.1 μg / mL. The surface oligomer extraction solvent and standard solution were analyzed by high-performance liquid chromatography (HPLC) under the following conditions to measure the amount of cyclic trimer and determine the amount of oligomer extracted per measured film area [mg / m].2 ]. Equipment: Shimadzu LC-10A Column: Inertsil ODS-3 Mobile phase: acetonitrile / water = 70 / 30 Flow rate: 1.5mL / min Detector: UV242nm Injection volume: 10μL.

[0100] (24) Crystallinity Measurements and analysis were performed in accordance with JIS K-7121 (1987 edition) using a Seiko Instruments Inc. DSC-RDC6220 differential scanning calorimeter robot and SII NanoTechnology Inc.'s "Muse" thermal analysis rheology system software for data analysis. A 5 mg film sample was placed on an aluminum pan and heated from room temperature to 300°C at a rate of 20°C / min, then held at 300°C for 5 minutes. The endothermic peak heat ΔHm, cold crystallization heat ΔHc, and heat of fusion ΔHm0 (140.1 J / g) of fully crystalline PET were used to calculate ΔHm using the following formula. Note that if there are multiple endothermic peaks, the sum of all ΔHm values ​​was used. Crystallinity (%) = ((ΔHm-ΔHc) / ΔHm0)×100.

[0101] (25) Mold contamination by oligomers (23) The value obtained by measuring the amount of oligomer extracted is evaluated according to the following criteria. A: Oligomer extraction amount is 1.0 mg / m 2 less than B: Oligomer extraction amount is 1.0 mg / m 2 More than 2.0mg / m 2 less than C: Oligomer extraction amount is 2.0 mg / m 2 More than 3.0mg / m 2 less than D: Oligomer extraction amount is 3.0 mg / m 2 More than 5.0mg / m 2 less than E: Oligomer extraction amount is 5.0 mg / m 2 Exceeds. A grade of D or above is considered a pass.

[0102] (26) Frequency of mold cleaning due to oligomer deposition on release film The frequency of mold cleaning required due to mold contamination caused by oligomer deposition on the release film is evaluated according to the following criteria. A: Cleaning frequency due to oligomer deposition is less than four times a year B: Cleaning frequency due to oligomer deposition is 4 to 8 times per year C: Cleaning frequency due to oligomer deposition is 8 to 12 times per year D: Cleaning frequency due to oligomer deposition is 12 to 24 times per year E: Cleaning frequency due to oligomer deposition is 24 times or more per year A grade of D or above is considered a pass. [Example]

[0103] The present invention will be described below with reference to examples, but the present invention is not necessarily limited to these examples.

[0104] 1. Polyester manufacturing The polyester resin used to form the layer A was prepared as follows.

[0105] (Polyester A) Polyethylene terephthalate resin (intrinsic viscosity 0.65) containing 100 mol % terephthalic acid as the dicarboxylic acid component and 100 mol % ethylene glycol as the glycol component.

[0106] (Polyester B) Isophthalic acid copolymerized polyethylene terephthalate resin (intrinsic viscosity 0.70) in which 17.5 mol% of the isophthalic acid component is copolymerized with the acid component.

[0107] (Polyester C) Spiroglycol copolymerized polyethylene terephthalate resin (intrinsic viscosity 0.72) in which spiroglycol is copolymerized at 20 mol% of the glycol component.

[0108] (Polyester D) Cyclohexanedimethanol copolymerized polyethylene terephthalate resin (intrinsic viscosity 0.75) in which 1,4-cyclohexanedimethanol is copolymerized at 33 mol% with respect to the glycol component.

[0109] (Polyester E) 2,6-Naphthalenedicarboxylic acid copolymerized polyethylene terephthalate resin (intrinsic viscosity 0.70) in which 2,6-naphthalenedicarboxylic acid is copolymerized at 15 mol% relative to the acid component.

[0110] (Polyester F) Isosorbide copolymerized polyethylene terephthalate resin (intrinsic viscosity 0.73) in which 25 mol% of isosorbide is copolymerized with the glycol component.

[0111] (Polyester G) A resin (intrinsic viscosity 0.70) made by blending isophthalic acid copolymerized polyethylene terephthalate resin (intrinsic viscosity 0.70), in which 11 mol% of isophthalic acid components are copolymerized with the acid components, with polyethylene glycol 1000 (molecular weight 1000) in a ratio (mass ratio) of 94:6.

[0112] (Polyester H) Thermoplastic polyether ester elastomer "Hytrel" (registered trademark) 7247 manufactured by Toray DuPont Co., Ltd.

[0113] 2. Particle Master Fabrication (Particle Master A) A masterbatch (intrinsic viscosity 0.65) containing agglomerated silica particles (specific gravity 2.2) with an average particle size of 1.6 μm in polyester A at a particle concentration of 10 mass %.

[0114] (Particle Master B) A masterbatch (intrinsic viscosity 0.60) containing zeolite particles (specific gravity 2.2) with an average particle size of 2.5 μm in polyester A at a particle concentration of 50 mass %.

[0115] (Particle Master C) A masterbatch (intrinsic viscosity 0.60) containing barium sulfate particles (specific gravity 4.5) with an average particle size of 6.0 μm in polyester A at a particle concentration of 50 mass%.

[0116] 3. Manufacturing of coating materials for release layers The coating material used for the release layer was prepared by mixing the following composition.

[0117] (Coating material α-1) 10 parts by mass, in terms of solid content, of long-chain alkyl group-containing polyvinyl resin ("Peiroil" (registered trademark) 1050, manufactured by Lion Specialty Chemicals Co., Ltd.), 2.5 parts by mass, in terms of solid content, of melamine-based crosslinking agent ("Sumimal" (registered trademark) M-55, manufactured by Sumitomo Chemical Co., Ltd.), 1.5 parts by mass, in terms of solid content, of p-toluenesulfonic acid ("TAYCACURE" (registered trademark) AC-700, manufactured by Tayca Corporation), 200 parts by mass, and 70 parts by mass of methyl ethyl ketone.

[0118] 4. Manufacturing of release films for semiconductor molds (Examples 1 to 18, Comparative Examples 1 to 5) The raw materials were mixed to the composition and layer structure shown in the table and fed into separate vented co-rotating twin-screw extruders with an oxygen concentration of 0.2% by volume. The extruder cylinder for the polyester resin A layer was set to 270°C, and the extruder cylinder for the polyester resin B layer was set to 280°C. The temperature of the short pipe where the polyester resin A layer and polyester resin B layer merged was set to 270°C, the die temperature was set to 270°C, and the extruder was extruded into a sheet form from a T-die onto a cooling drum temperature-controlled at 25°C. Electrostatic charge was applied using a 0.1 mm diameter wire electrode, and the film was brought into close contact with the cooling drum to obtain an unstretched sheet. The side in contact with the drum surface was designated the D-side, and the opposite side was designated the ND-side. The film temperature was then increased using a heated roll before longitudinal stretching. The film was stretched 3.3 times in the longitudinal direction at a stretching temperature of 85°C, and immediately cooled using a metal roll temperature-controlled at 30°C.

[0119] The film was then stretched 3.6 times in the width direction using a tenter-type transverse stretching machine at a preheating temperature of 85°C and a stretching temperature of 95°C, and then heat-treated at constant length in an atmosphere of 235°C for 12 seconds.After that, it was subjected to a 2% relaxation treatment at the same temperature, and then further to a 2% relaxation treatment at a temperature of 200°C to obtain a polyester film of the thickness shown in the table.

[0120] Next, to form a release layer, the polyester film obtained above was cooled to room temperature, and then coating material α-1 was applied to the D side of the film using a gravure coating method.The film was then transported to an oven at 110°C to pre-dry the coating, and then heated and dried in an oven at 160°C to obtain a release film for semiconductor molds with a release layer thickness of 250 nm.

[0121] The properties of the release films obtained above are as shown in the table, and it was found that the release films for semiconductor molds in the examples had very good compression mold processability.

[0122] [Table 1]

[0123] [Table 2]

[0124] [Table 3]

[0125] [Table 4]

[0126] [Table 5]

[0127] [Table 6]

[0128] [Table 7]

[0129] [Table 8] [Industrial Applicability]

[0130] The release film for a semiconductor mold of the present invention can provide an excellent design, has excellent formability during molding, and suppresses film breakage, and can provide a method for producing a semiconductor chip encapsulated body and a semiconductor. By suitably using such a release film as a release film for compression molding performed in the semiconductor encapsulation step, mass productivity of semiconductor chips can be improved. [Explanation of symbols]

[0131] 1. Mold 2 guide pins 3 Tent diameter 4 Suction hole 5 Lower release film 6 silicon wafers 7 Molding resin 8 Upper release film

Claims

1. A laminated film including a release layer and a polyester resin layer, the film stiffness at 175°C in either the longitudinal direction or the width direction being 5.0 N·mm·10 －３ Above, 20N・mm・10 －３ or less, and the number of protrusions with a height of 1 μm or more on at least one of the outermost layers is 500 / mm ２ More than 8000 pieces / mm ２ A semiconductor mold release film as follows:

2. 2. The release film for a semiconductor mold according to claim 1, wherein the polyester resin layer is a laminate of two or more layers having at least a polyester resin A layer and a polyester resin B layer, the polyester resin A layer having an inorganic particle content of 5% by mass or more and 19% by mass or less, and the polyester resin B layer having an inorganic particle content of less than 5% by mass.

3. 3. The release film for a semiconductor mold according to claim 1, wherein the breaking stress at 175°C is 20 MPa or more and 100 MPa or less in both the longitudinal direction and the width direction.

4. 3. The release film for a semiconductor mold according to claim 1, wherein the cushioning factor is 60% or more and less than 88%.

5. 3. The release film for a semiconductor mold according to claim 2, wherein the void content Va of the polyester resin A layer is 10.0% or more and 30.0% or less, and the void content Vz of the entire film is 2.0% or more and 10.0% or less.

6. Density is 1.10 g / cm ３ 1.34g / cm or more ３ 3. The release film for a semiconductor mold according to claim 1 or 2, wherein:

7. 3. The release film for a semiconductor mold according to claim 1, wherein the optical density is from 0.1 to 2.

0.

8. After heating at 185°C for 30 minutes, the amount of oligomer extracted was 0 mg / m ２ Above, 5.0mg / m ２ 3. The release film for a semiconductor mold according to claim 1 or 2, wherein:

9. 3. The release film for a semiconductor mold according to claim 1, wherein the crystallinity is from 3.0% to 21.0%.

10. 10. A method for producing a semiconductor chip sealed body, comprising the step of placing the release film for semiconductor molding according to claim 1 in a mold in a compression device so that the release layer and molding resin come into contact with each other, and performing compression molding.

11. 11. The method for manufacturing a semiconductor chip sealing body according to claim 10, wherein the molding resin is in the form of granules.

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