Release film for semiconductor encapsulation, marking film for semiconductor encapsulation, semiconductor package, and method for manufacturing a semiconductor package

Abstract

To provide a release film for semiconductor encapsulation having an outermost layer with excellent adhesion to the surface of a semiconductor package. [Solution] The release film for semiconductor encapsulation comprises a substrate, a release layer, and a thermosetting colored layer in that order, or a substrate, a release layer, and at least one functional layer in that order, wherein the outermost layer of the functional layer contains a thermosetting resin.

Description

Technical Field

[0001] The present disclosure relates to a release film for semiconductor encapsulation, a marking film for semiconductor encapsulation, a semiconductor package, and a method for manufacturing a semiconductor package.

Background Art

[0002] With the miniaturization, thinning, and lightening of electronic devices, the miniaturization and thinning of semiconductor packages have been progressing. By encapsulating semiconductor elements with a thermosetting resin encapsulant, the above-described semiconductor packages are obtained. However, with the thinning of the semiconductor packages, the encapsulation resin layer for encapsulating the semiconductor elements is also becoming thinner.

[0003] In resin-encapsulated semiconductor packages, various identification information such as manufacturing lot numbers and logo marks is printed on the surface of the encapsulation resin layer. As one of the printing methods for the surface of the encapsulation resin layer, a printing method using ink mainly composed of a thermosetting resin or an ultraviolet curable resin is performed. However, for printing with ink, it may be necessary to go through the steps of applying, curing, and cleaning the ink, which may complicate the manufacturing process of the semiconductor package or may not ensure the durability of the ink.

[0004] As a printing method for solving these problems, a laser marking method is performed in which the surface of the encapsulation resin layer is engraved with a laser for printing. The laser marking method is a technique in which the surface of the encapsulation resin layer is scraped off by laser light for printing. According to the laser marking method, since the encapsulation resin layer is directly engraved, additional processes such as cleaning are not required, the production efficiency is higher than that of the printing method, and the durability of the printing is improved.

[0005] In addition, a sealing sheet exhibiting excellent laser marking properties has been proposed (see, for example, Patent Document 1 or 2). In the sealing sheet described in Patent Document 1 or 2, a resin layer having excellent laser marking properties and an encapsulation resin layer for encapsulating semiconductor elements are laminated.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Patent No. 4682796 [Patent Document 2] Japanese Patent Publication No. 2015-043378 [Overview of the project] [Problems that the invention aims to solve]

[0007] The encapsulating resin layer that seals semiconductor elements is located on the outermost layer of the semiconductor package, and therefore requires an excellent appearance. On the other hand, because the encapsulating resin layer contains a large amount of filler, the amount of colorant added may be small. Furthermore, carbon black, which is widely used as a colorant, exhibits conductivity, so from a reliability standpoint, it may not be possible to add it in high concentrations to the encapsulating resin layer. For these reasons, the blackness of the encapsulating resin layer may be insufficient, resulting in a poor appearance of the semiconductor package. In addition, when various information is printed on the surface of the encapsulating resin layer using laser marking, insufficient colorant may reduce the contrast of the encapsulating resin layer, resulting in poor visibility of the print. Furthermore, as described above, the sealing sheets disclosed in Patent Document 1 or 2 have a structure in which a resin layer with excellent laser marking properties and a sealing resin layer for sealing semiconductor elements are pre-laminated. Therefore, the type of sealing material is limited to the material constituting the sealing resin layer. Consequently, there is less freedom in selecting the sealing material.

[0008] On the other hand, by using a release film for semiconductor package molding that has a colored layer to compress the semiconductor package, the colored layer is transferred to the surface of the semiconductor package after molding. However, when the colored layer is transferred, wrinkles may occur on the surface of the semiconductor package to which the colored layer has been transferred. Furthermore, when a semiconductor package is compression-molded using a release film for semiconductor encapsulation that has a colored layer as the outermost layer, the colored layer is transferred to the surface of the semiconductor package after molding. However, the adhesion of the colored layer transferred to the surface of the semiconductor package may be low. Low adhesion of the colored layer can lead to problems such as the colored layer peeling off from the semiconductor package. Therefore, there is a need to improve the adhesion of functional layers such as the colored layer to the surface of the semiconductor package.

[0009] One aspect of this disclosure has been made in view of the above-mentioned conventional circumstances and aims to provide a semiconductor encapsulation release film that has a colored layer and provides excellent appearance of the semiconductor package surface when the colored layer is transferred to the surface of the semiconductor package. Another aspect of this disclosure aims to provide a semiconductor package using a semiconductor encapsulation release film and a method for manufacturing the same. Furthermore, another aspect of this disclosure aims to provide a semiconductor encapsulation marking film that constitutes a part of the semiconductor encapsulation release film. Another aspect of this disclosure, made in view of the above-described conventional circumstances, aims to provide a release film for semiconductor encapsulation having an outermost layer with excellent adhesion to the surface of a semiconductor package, a semiconductor package using this release film, and a method for manufacturing the same. [Means for solving the problem]

[0010] The specific means for achieving the aforementioned objectives are as follows: <1> A release film for semiconductor encapsulation, comprising a base material, a release layer, and a thermosetting colored layer in that order. <2> The aforementioned colored layer contains a coloring agent, a thermosetting resin, and a curing agent. <1> Release film for semiconductor encapsulation as described above. <3> The thermosetting resin includes an epoxy resin. <2> Release film for semiconductor encapsulation as described above. <4> The aforementioned substrate contains polyester resin <1> ~ <3> A release film for semiconductor encapsulation as described in any one of the items. <5> The colored layer is transferred to the surface of the encapsulating resin layer of the semiconductor package. <1> ~ <4> A release film for semiconductor encapsulation as described in any one of the items. <6> A release film for semiconductor encapsulation, comprising a base material, a release layer, and at least one functional layer in that order, wherein the outermost of the functional layers contains a thermosetting resin. <7> The functional layer is transferred to the surface of the encapsulating resin layer of the semiconductor package. <6> Release film for semiconductor encapsulation as described above. <8> A semiconductor package is manufactured by compression molding using the aforementioned semiconductor encapsulation release film and a semiconductor encapsulation resin containing epoxy resin, under the conditions of a mold temperature of 165°C, a molding pressure of 6.86 MPa, and a molding time of 180 seconds, followed by thermal curing at a curing temperature of 175°C, under atmospheric pressure, and for a curing time of 120 minutes. Laser marking is performed on the surface of the functional layer transferred to the semiconductor package under the conditions of wavelength 1064 nm, intensity 4 W, scan speed 1000 mm / sec, and Q-switch frequency: 120 kHz. The laser-marked portion of the semiconductor package is cut into 100 squares of 1 mm each. Adhesive tape conforming to JIS K5600-5-6:1999 is applied to the cut portions. Within 5 minutes of application, the edge of the adhesive tape is grasped and peeled off at a 60° angle for 0.5 to 1.0 seconds. In this case, the remaining portion of the functional layer in the peeled portion is 70 squares or more. <6> or <7> Release film for semiconductor encapsulation as described above. <9> The functional layer includes a colored layer. <6> ~ <8> A release film for semiconductor encapsulation as described in any one of the items. <10> The functional layer includes the colored layer and a functional layer different from the colored layer as the outermost layer, in this order from the substrate side. <9> Release film for semiconductor encapsulation as described above. <11> The thermosetting resin includes an epoxy resin. <6> ~ <10> A release film for semiconductor encapsulation as described in any one of the items. <12> The aforementioned colored layer contains a coloring agent, a thermosetting resin, and a curing agent. <9> ~ <11> A release film for semiconductor encapsulation as described in any one of the items. <13> The thermosetting resin contained in the colored layer includes an epoxy resin. <12> Release film for semiconductor encapsulation as described above. <14> The aforementioned substrate contains polyester resin <6> ~ <13> A release film for semiconductor encapsulation as described in any one of the items. <15> The storage modulus of the cured product obtained by heat-treating the outermost layer under the conditions of a temperature of 165°C, a pressure of 6.86 MPa, and a time of 180 seconds is 0.1 GPa or higher at 165°C. <6> ~ <14> A release film for semiconductor encapsulation as described in any one of the items. <16> The outermost layer contains an inorganic filler, and the amount of the inorganic filler is 40% by mass or more based on the total mass of the outermost layer. <6> ~ <15> A release film for semiconductor encapsulation as described in any one of the items. <17> The semiconductor element comprises a sealing resin layer that encloses the semiconductor element, and a colored layer provided on the surface of the sealing resin layer, wherein the colored layer is <1> ~ <5> A semiconductor package having a layer derived from the colored layer of a release film for semiconductor encapsulation described in any one of the above items. <18> The device comprises a semiconductor element, a sealing resin layer that seals the semiconductor element, and a functional layer provided on the surface of the sealing resin layer, wherein the functional layer is <6> ~ <16> A semiconductor package having a layer derived from a functional layer of a release film for semiconductor encapsulation described in any one of the above items. <19> Semiconductor elements and <1> ~ <5> A method for manufacturing a semiconductor package, comprising the step of sealing a semiconductor element while arranging the semiconductor element and the semiconductor encapsulation release film in a mold such that the colored layer side of the semiconductor encapsulation release film described in any one of the items is facing the semiconductor element. <20> Semiconductor elements and <6> ~ <16> A method for manufacturing a semiconductor package, comprising the step of sealing a semiconductor element while arranging the semiconductor element and the semiconductor encapsulation release film in a mold such that they face each other with the outermost layer of the semiconductor encapsulation release film described in any one of the items. <21> A marking film for semiconductor encapsulation having a thermosetting colored layer. <22> It further comprises a functional layer different from the aforementioned colored layer. <21> The semiconductor encapsulation marking film described above. [Effect of the Invention]

[0011] According to one aspect of the present disclosure, there can be provided a release film for semiconductor encapsulation including a coloring layer, which has an excellent appearance of the surface of a semiconductor package when the coloring layer is transferred to the surface of the semiconductor package. Further, according to one aspect of the present disclosure, there can be provided a semiconductor package using the release film for semiconductor encapsulation and a method for manufacturing the same. Furthermore, according to one aspect of the present disclosure, there can be provided a marking film for semiconductor encapsulation that constitutes a part of the release film for semiconductor encapsulation. Also, according to another aspect of the present disclosure, there can be provided a release film for semiconductor encapsulation having an outermost layer with excellent adhesion to the surface of a semiconductor package, a semiconductor package using this release film for semiconductor encapsulation, and a method for manufacturing the same. [Modes for Carrying Out the Invention]

[0012] Hereinafter, embodiments for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, its components (including element steps, etc.) are not essential unless specifically stated. The same applies to numerical values and their ranges, which do not limit the present disclosure. In the present disclosure, the term "step" includes not only a step independent from other steps but also a step that cannot be clearly distinguished from other steps as long as the purpose of the step is achieved. In the numerical range indicated by "~" in the present disclosure, the numerical values described before and after "~" are included as the minimum value and the maximum value, respectively. In the numerical ranges described step by step in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other step-by-step descriptions. Also, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. In the present disclosure, each component may contain a plurality of corresponding substances. When a plurality of substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the plurality of substances present in the composition, unless otherwise specified. In the present disclosure, the particles corresponding to each component may include a plurality of types of particles. When a plurality of types of particles corresponding to each component are present in the composition, the particle size of each component means the value for the mixture of the plurality of types of particles present in the composition, unless otherwise specified. In the present disclosure, the term "layer" or "film" includes not only the case where it is formed over the entire region where the layer or film exists, but also the case where it is formed only in a part of the region when observing the region where the layer or film exists. In the present disclosure, the term "lamination" indicates stacking layers, and two or more layers may be bonded, and two or more layers may be detachable. In the present disclosure, "(meth)acryl" means at least one of acrylic and methacrylic, and "(meth)acrylate" means at least one of acrylate and methacrylate.

[0013] In the present disclosure, the average thickness of a layer or film (also referred to as the average value of the thickness) is the value given as the arithmetic mean of the thicknesses at five points of the target layer or film. The thickness of a layer or film can be measured using a micrometer or the like. In the present disclosure, when the thickness of a layer or film can be directly measured, it is measured using a micrometer. On the other hand, when measuring the thickness of one layer among the plurality of layers in a state where the plurality of layers are laminated or the total thickness of the plurality of layers, it may be measured by observing the cross-section of the measurement target using an electron microscope.

[0014] In this disclosure, "average particle diameter" is determined as the particle diameter (50%D) at which the cumulative volume distribution curve from the small particle diameter side reaches 50% in the volume cumulative particle size distribution curve obtained by the laser diffraction scattering particle size distribution measurement method. For example, it can be measured using a particle size distribution analyzer that utilizes the laser light scattering method (for example, "SALD-3000" manufactured by Shimadzu Corporation).

[0015] <Release film for semiconductor encapsulation> The first semiconductor encapsulation release film of this disclosure (hereinafter sometimes referred to as the "first release film") comprises a substrate, a release layer, and a thermosetting colored layer in this order. The first semiconductor encapsulation release film of this disclosure exhibits excellent appearance of the semiconductor package surface when a colored layer is transferred to the surface of the semiconductor package. The reason for this is not clear, but it is presumed to be as follows. A semiconductor package is manufactured by encapsulating a semiconductor element with an encapsulant while the semiconductor element and the release film are placed in a mold so that the semiconductor element and the colored layer side of the release film face each other. When encapsulating the semiconductor element with the encapsulant, a pressurized treatment is performed under predetermined temperature conditions. Through this pressurized treatment, the colored layer is transferred to the surface of the encapsulating resin layer that encapsulates the semiconductor element (i.e., the surface of the semiconductor package). In the first semiconductor encapsulation release film of this disclosure, the colored layer is in a flexible state before curing when encapsulating a semiconductor element. Therefore, it is possible to alleviate the stress applied when encapsulating the semiconductor element, and as a result, it is presumed that the occurrence of appearance defects such as wrinkles in the colored layer will be suppressed, and the appearance of the semiconductor package surface when the colored layer is transferred to the surface of the semiconductor package will be excellent. Furthermore, since the colored layer is thermosetting, it hardens due to the heat of the heat curing process after encapsulation. It is presumed that as the colored layer hardens, it adheres firmly to the surface of the encapsulating material, resulting in a semiconductor package with excellent heat resistance. "The semiconductor element and the colored layer side of the release film face each other" means that the surface of the release film on the side with the colored layer faces the semiconductor element. If the surface of the release film is a colored layer, then the semiconductor element and the colored layer of the release film will face each other.

[0016] The first semiconductor encapsulation release film of this disclosure comprises a substrate, a release layer, and a colored layer, and may optionally have other layers. The following describes the various materials that constitute the first semiconductor encapsulation release film of this disclosure.

[0017] (base material) The first release film has a base material. The base material is not particularly limited and can be appropriately selected from resin-containing base materials used in the art. From the viewpoint of improving conformability to the shape of the mold, it is preferable to use a resin-containing base material with excellent stretchability. Considering that the encapsulation of semiconductor devices with encapsulating materials is performed at high temperatures (approximately 100°C to 200°C), it is desirable that the substrate has heat resistance above this temperature. Furthermore, in order to suppress the occurrence of wrinkles in the encapsulating resin and tears in the release film when the release film is attached to the mold and when the resin flows during molding, it is important to select a substrate that takes into account the elastic modulus and elongation at high temperatures.

[0018] The base material preferably contains a polyester resin from the viewpoint of heat resistance and elastic modulus at high temperatures. Examples of polyester resins include polyethylene terephthalate resin, polyethylene naphthalate resin, and polybutylene terephthalate resin, as well as copolymers and modified resins thereof. As the base material, a polyester resin molded into a film is preferred, a polyester film is more preferred, a biaxially oriented polyester film is even more preferred from the viewpoint of conformability to the mold, and a biaxially oriented polyethylene terephthalate film is particularly preferred. The average thickness of the substrate is not particularly limited, but is preferably 5 μm to 100 μm, and more preferably 10 μm to 70 μm. When the average thickness is 5 μm or more, it is easy to handle and tends to be less prone to wrinkling. When the average thickness is 100 μm or less, it is easy to follow the mold during molding, which tends to suppress the occurrence of wrinkles in the molded semiconductor package.

[0019] (Release layer) The first release film has a release layer. Delamination occurs between the release layer and the colored layer in the first release film, and the colored layer is transferred to the surface of the semiconductor package. The components constituting the release layer are not particularly limited, and various materials used in the art can be used in combination. The release layer may contain, for example, resin particles and a binder, and may also contain other components as needed.

[0020] -Resin particles- The type of resin constituting the resin particles is not particularly limited. Preferably, the resin particles contain at least one selected from the group consisting of acrylic resin, polyolefin resin, polystyrene resin, polyacrylonitrile resin, and silicone resin. From the viewpoint of release properties for semiconductor packages, it is more preferable that the resin particles contain at least one selected from acrylic resin, polystyrene resin, and polyacrylonitrile resin. From the viewpoint of uniformity of the surface appearance of semiconductor packages, it is preferable that the resin particles are insoluble or sparingly soluble in organic solvents (e.g., toluene, methyl ethyl ketone, and ethyl acetate) that can be used in the preparation of release layer forming compositions. Here, insoluble or sparingly soluble in organic solvents means that, in a gel fraction test in accordance with JIS K6769:2013, the gel fraction after dispersing the resin particles in an organic solvent such as toluene and holding them at 50°C for 24 hours is 97% or more.

[0021] Examples of acrylic resins include (meth)acrylic monomer (copolymers), such as (meth)acrylic acid resins and (meth)acrylic acid ester resins (e.g., alkyl (meth)acrylate resins and dimethylaminoethyl (meth)acrylate resins). Copolymers of (meth)acrylic monomers may also contain monomers other than (meth)acrylic monomers as copolymer components. (Meth)acrylic monomers include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, s-butyl acrylate, s-butyl methacrylate, t-butyl acrylate, t-butyl methacrylate, pentyl acrylate, methacrylate Pentyl acrylate, hexyl acrylate, hexyl methacrylate, heptyl acrylate, heptyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, octyl acrylate, octyl methacrylate, nonyl acrylate, nonyl methacrylate, decyl acrylate, decyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tetradecyl acrylate, tetradecyl methacrylate, hexadecyl acrylate, hexadecyl methacrylate Examples include octadecyl acrylate, octadecyl methacrylate, eicosyl acrylate, eicosyl methacrylate, docosyl acrylate, docosyl methacrylate, cyclopentyl acrylate, cyclopentyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, cycloheptyl acrylate, cycloheptyl methacrylate, benzyl acrylate, benzyl methacrylate, phenyl acrylate, phenyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, dimethylaminopropyl acrylate, dimethylaminopropyl methacrylate, dicyclopentanyl acrylate, dicyclopentanyl methacrylate, 2-chloroethyl acrylate, 2-chloroethyl methacrylate, 2-fluoroethyl acrylate, and 2-fluoroethyl methacrylate. Examples of monomers other than (meth)acrylic monomers include styrene, α-methylstyrene, cyclohexylmaleimide, vinyltoluene, vinyl chloride, vinyl acetate, N-vinylpyrrolidone, butadiene, isoprene, and chloroprene. These monomers may be used individually or in combination of two or more. The polyolefin resin is not particularly limited as long as it is a (co)polymer of olefin monomers. Specifically, examples include polyethylene, polypropylene, and polymethylpentene. Examples of polystyrene resins include (co)polymers of styrene or styrene derivatives. Examples of styrene derivatives include alkyl-substituted styrenes having alkyl chains such as α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, and 4-ethylstyrene; chlorine-substituted styrenes such as 2-chlorostyrene, 3-chlorostyrene, and 4-chlorostyrene; fluorine-substituted styrenes such as 4-fluorostyrene and 2,5-difluorostyrene; and vinylnaphthalene. Examples of polyacrylonitrile resins include (co)polymers of acrylonitrile monomers. From the viewpoint of suppressing the solubility of resin particles in organic solvents, it is preferable that the resin contained in the resin particles is a crosslinked resin.

[0022] The average particle size of the resin particles is preferably 1 μm to 55 μm. When the average particle size of the resin particles is 1 μm or more, it is possible to sufficiently form irregularities on the surface of the release layer, which improves the uniformity of the surface appearance of the molded semiconductor package and tends to suppress flow marks of the encapsulating material. Furthermore, when the average particle size of the resin particles is 55 μm or less, it is preferable from a cost standpoint because it is not necessary to excessively increase the thickness of the release layer in order to fix the resin particles in the release layer. From the viewpoint of semiconductor package surface appearance, the upper limit of the average particle diameter of the resin particles is preferably 55 μm, and more preferably 50 μm. From the viewpoint of cost, the lower limit of the average particle diameter of the resin particles is more preferably 2 μm, even more preferably 3 μm, and particularly preferably 5 μm.

[0023] The shape of the resin particles contained in the release layer is not particularly limited and may be spherical, elliptical, irregular, or any other shape.

[0024] Specific examples of resin particles include the Toughtic series, such as Toughtic FH-S010 (manufactured by Toyobo Co., Ltd.), which are acrylic resin particles.

[0025] The resin particle content in the release layer is preferably 5% to 65% by volume. When the content is 5% by volume or more, it is possible to sufficiently form irregularities on the surface of the release layer, which tends to improve the uniformity of the surface appearance of the molded semiconductor package and sufficiently suppress the flow marks of the encapsulant. From this viewpoint, the lower limit of the resin particle content is more preferably 10% by volume, and even more preferably 20% by volume. Furthermore, when the content is 65% by volume or less, the resin particles are more easily fixed by the binder in the release layer (described later), reducing the possibility of resin particle detachment, suppressing contamination of the molded semiconductor package surface, and also being economically preferable. From this viewpoint, the upper limit of the resin particle content is more preferably 60% by volume, and even more preferably 50% by volume.

[0026] -binder- There are no particular limitations on the type of binder that may be included in the release layer. The inclusion of a binder in the release layer helps to fix the resin particles within the layer. The binder is preferably made of acrylic resin or silicone resin, and more preferably of a cross-linked acrylic resin (hereinafter also referred to as "cross-linked acrylic copolymer"), from the viewpoint of release properties from the semiconductor package and heat resistance.

[0027] The acrylic resin is preferably an acrylic copolymer obtained by copolymerizing a low glass transition temperature (Tg) monomer, such as butyl acrylate, ethyl acrylate, or 2-ethylhexyl acrylate, with a functional group monomer such as acrylic acid, methacrylic acid, hydroxyethyl methacrylate, hydroxyethyl acrylate, acrylamide, or acrylonitrile. Furthermore, a crosslinked acrylic copolymer can be produced by crosslinking the above acrylic copolymer using a crosslinking agent. Known crosslinking agents used in the production of crosslinked acrylic copolymers include isocyanate compounds, melamine compounds, and epoxy compounds. Furthermore, in order to form a network structure that spreads gently within the acrylic resin, it is more preferable that the crosslinking agent be a polyfunctional crosslinking agent such as a trifunctional or tetrafunctional agent.

[0028] Since the crosslinked acrylic copolymer produced using the crosslinking agent described above has a gently expanding network structure, using this crosslinked acrylic polymer as a binder for the release layer improves the stretchability of the release layer and suppresses the inhibition of the stretchability of the substrate, thereby improving the conformability of the release film to the mold during compression molding. From this perspective, the amount of crosslinking agent used in the production of crosslinked acrylic copolymer is preferably 3 to 100 parts by mass, and more preferably 5 to 70 parts by mass, per 100 parts by mass of acrylic copolymer. When the amount of crosslinking agent is 3 parts by mass or more, the strength of the binder is ensured, which reduces the possibility of resin particle detachment and tends to prevent contamination of the molded semiconductor package surface. When the amount of crosslinking agent is 100 parts by mass or less, the flexibility of the crosslinked acrylic copolymer tends to improve, and the stretchability of the release layer tends to improve.

[0029] -Other ingredients- The release layer may further contain, if necessary, a solvent, an anchoring enhancer, a crosslinking accelerator, an antistatic agent, a colorant, etc.

[0030] - Thickness of the release layer - The thickness of the release layer is not particularly limited and is set appropriately considering its relationship with the average particle size of the resin particles used. The average thickness of the release layer is preferably 0.1 μm to 100 μm, and more preferably 1 μm to 50 μm. If the average thickness of the release layer is not extremely thin compared to the average particle size of the resin particles used, it becomes less difficult to fix the resin particles within the release layer, and the likelihood of the resin particles falling off is less likely to increase. Therefore, contamination of the molded semiconductor package surface by the release layer tends to be less likely. Furthermore, if the average thickness of the release layer is not extremely thick compared to the average particle size of the resin particles used, it tends to be easier to obtain effects such as improved uniformity of the surface appearance of the molded semiconductor package and suppression of flow marks of the encapsulating material. In addition, it tends to be less economically disadvantageous. In this disclosure, the average thickness of the release layer refers to the dry thickness, which is obtained by measuring the release layer of the release film using the method described above for measuring the average thickness of the layer.

[0031] (colored layer) The first release film has a thermosetting colored layer. On the surface of the semiconductor package, the portion of the colored layer removed by laser marking or the like is recognized as identification information. The components constituting the colored layer are not particularly limited as long as they are components that cause the colored layer to exhibit thermosetting properties, and various materials used in the relevant art can be used in combination. The colored layer may, for example, contain a colorant, a thermosetting resin, and a curing agent. The colored layer may also contain other components such as a curing accelerator, a thermoplastic resin, an inorganic filler, a coupling agent, and various additives. Examples of additives that may be included in the colored layer include release agents, antioxidants, surface tension modifiers, leveling agents, ion exchangers, and ion scavengers. The colored layer may be one layer or two or more layers. If there are two or more colored layers, the colorants contained in each layer may be the same or different, but it is preferable that they be different.

[0032] In this disclosure, "a colored layer exhibits thermosetting properties" means that the heat generated by differential scanning calorimetry of the colored layer is 1 J / g or more. The conditions for measuring the heat generated by the colored layer are as follows: A differential scanning calorimeter (product name: DSC Q1000, manufactured by T.A. Instruments) is used to measure a 10 mg sample of the colored layer. The sample is heated from room temperature (25°C) to 300°C at a rate of 5°C / min to obtain a DSC curve during the heating process. The exothermic peak appearing in the obtained DSC curve is defined as the exothermic peak of the colored layer determined by differential scanning calorimetry. The amount of heat generated by the exothermic peak is calculated from the area of ​​the exothermic peak appearing in the DSC curve. The colored layer can be obtained by scraping it off the release film with a spatula or similar tool. The heat generation of the colored layer is preferably 1 J / g to 300 J / g, and more preferably 5 J / g to 100 J / g. If there are two or more colored layers, it is desirable that the total heat generated by the colored layers as a whole falls within the above range. To measure the total heat generated by the colored layers as a whole, you can use a sample obtained by scraping off two or more colored layers together from the release film as the measurement sample.

[0033] The average thickness of the colored layer is preferably 3 μm to 100 μm, and more preferably 5 μm to 60 μm. If there are two or more colored layers, it is preferable that the average thickness of each colored layer falls within the above range.

[0034] -Colorants- The colored layer may contain a coloring agent. Various organic pigments, inorganic pigments, etc., can be used as coloring agents. Examples of coloring agents include black pigment, white pigment, yellow pigment, magenta pigment, cyan pigment, red pigment, blue pigment, green pigment, etc. Among these, black pigment and white pigment are preferred from the viewpoint of visibility of various information printed on the surface of the semiconductor package. Examples of black pigments include acetylene black, carbon black such as Ketjen black, titanium black, and aniline black. Examples of white pigments include basic lead carbonate (2PbCO3·Pb(OH)2), zinc oxide (ZnO), titanium dioxide (TiO2), and strontium titanate (SrTiO3).

[0035] The concentration of the coloring agent in the colored layer can be set appropriately depending on the type of coloring agent. The content of the coloring agent in the colored layer is preferably 0.5% to 12% by mass, and more preferably 1% to 10% by mass, when a black pigment is used as the coloring agent. The content of the coloring agent in the colored layer is preferably 15% to 60% by mass, and more preferably 20% to 50% by mass, for example, when a white pigment is used as the coloring agent. When there are two colored layers, the first semiconductor encapsulation release film of this disclosure preferably has a substrate, a release layer, a colored layer containing a black pigment, and a colored layer containing a white pigment in this order. When a semiconductor package is molded using a release film with such a configuration, the colored layer containing a white pigment and the colored layer containing a black pigment are transferred to the surface of the semiconductor package in this order. By irradiating the surface of the semiconductor package to which the colored layers have been transferred with laser light, the resin in the colored layer containing the black pigment is sublimated, making it possible to scrape off the colored layer containing the black pigment. At this time, the colored layer containing the white pigment appears in the area where the colored layer containing the black pigment has been scraped off, resulting in high contrast and good visibility of the printed area. Furthermore, a colored layer containing a white pigment such as titanium dioxide as a coloring agent has a high ability to shield laser light and can be considered a functional layer (shielding layer) as described later.

[0036] The lasers used in laser marking are mainly carbon dioxide lasers and YAG lasers. Since YAG lasers are more commonly used in laser marking, it is preferable to use carbon black, which is easily volatile when exposed to a YAG laser, as the black pigment in the colored layer. Alternatively, a YVO4 laser can also be used in laser marking.

[0037] -Thermosetting resin- The colored layer may contain a thermosetting resin. Examples of thermosetting resins include epoxy resins, triazine resins, phenolic resins, melamine resins, cyanate ester resins, and modified versions of these resins. These resins may be used individually or in combination of two or more types. From the viewpoint of heat resistance, the thermosetting resin is preferably at least one selected from the group consisting of epoxy resins, phenolic resins, and triazine resins, and more preferably an epoxy resin.

[0038] As epoxy resins, difunctional epoxy resins such as bisphenol A type epoxy resin, novolac type epoxy resins such as phenol novolac type epoxy resin and cresol novolac type epoxy resin can be used. In addition, generally known resins such as polyfunctional epoxy resins, glycidylamine type epoxy resins, heterocyclic epoxy resins, and alicyclic epoxy resins can be applied. These epoxy resins may be used individually or in combination of two or more types.

[0039] The epoxy equivalent of the epoxy resin is preferably 10 g / eq to 20,000 g / eq, more preferably 20 g / eq to 5,000 g / eq, and even more preferably 50 g / eq to 1,000 g / eq. The epoxy equivalent of epoxy resin is measured by perchloric acid titration in accordance with JIS K7236:2009.

[0040] Examples of bisphenol A type epoxy resins include those manufactured by Mitsubishi Chemical Corporation, such as Epicote 807, 815, 825, 827, 828, 834, 1001, 1004, 1007, and 1009; those manufactured by Dow Chemical, such as DER-330, 301, and 361; and those manufactured by Shin-Nippon Chemical Epoxy Manufacturing Co., Ltd., such as YD8125 and YDF8170.

[0041] Examples of phenol novolac type epoxy resins include those manufactured by Mitsubishi Chemical Corporation (product names: Epicote 152, 154, etc.), Nippon Kayaku Co., Ltd. (product name: EPPN-201, etc.), and Dow Chemical Company (product name: DEN-438, etc.). Examples of o-cresol novolac type epoxy resins include those manufactured by Nippon Kayaku Co., Ltd. (product names: EOCN-102S, 103S, 104S, 1012, 1025, 1027, etc.) and those manufactured by Shin-Nippon Chemical Epoxy Manufacturing Co., Ltd. (product names: YDCN700-7A, YDCN701, 702, 703, 704, etc.).

[0042] Examples of polyfunctional epoxy resins include Epon 1031S (manufactured by Mitsubishi Chemical Corporation), Araldite 0163 (manufactured by Ciba Specialty Chemicals), and Denacol EX-611, 614, 614B, 622, 512, 521, 421, 411, and 321 (manufactured by Nagase Chemicals Ltd.). Examples of amine-type epoxy resins include Epicote 604 (manufactured by Mitsubishi Chemical Corporation), YH-434 (manufactured by Shin-Nippon Epoxy Manufacturing Co., Ltd.), TETRAD-X and TETRAD-C (manufactured by Mitsubishi Gas Chemical Company, Inc.), and ELM-120 (manufactured by Sumitomo Chemical Co., Ltd.).

[0043] Examples of heterocyclic epoxy resins include Araldite PT810 from Ciba Specialty Chemicals, ERL4234, 4299, 4221, 4206 from UCC, and TEPIC-S and TEPIC-PAS from Nissan Chemical Industries, Ltd.

[0044] Examples of alicyclic epoxy resins include those manufactured by Daicel Corporation, such as EHPE-3150, CEL2021P, and CEL2000.

[0045] The content of thermosetting resin in the colored layer is preferably 0.1% to 80% by mass, more preferably 1% to 60% by mass, and even more preferably 5% to 50% by mass. If there are two or more colored layers, it is preferable that the content of thermosetting resin in each colored layer is within the above range.

[0046] -Hardening agent- The colored layer may contain a curing agent. Any commonly used and known curing agent can be used. When the thermosetting resin is an epoxy resin, examples of curing agents include amines, polyamides, acid anhydrides, polysulfides, boron trifluoride, bisphenols having two or more phenolic hydroxyl groups in one molecule such as bisphenol A, bisphenol F, and bisphenol S, phenol novolac resins, bisphenol A novolac resins, cresol novolac resins, and other phenolic resins. Among these, phenolic resins, acid anhydrides, amines, etc. are preferred from the viewpoint of the curability of epoxy resins.

[0047] Examples of phenolic resins used as curing agents include those manufactured by DIC Corporation (product names: Phenolite LF2882, Phenolite LF2822, Phenolite TD-2090, Phenolite TD-2149, Phenolite VH-4150, Phenolite VH4170, etc.) and those manufactured by Mitsui Chemicals, Inc. (product names: XLC-LL, XLC-4L, etc.). These may be used individually or in combination of two or more types.

[0048] Examples of acid anhydrides used as curing agents include phthalic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, 4-methyltetrahydrophthalic anhydride, 3-methylhexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, Hymic anhydride, methylhymic anhydride, chlorendic anhydride, succinic anhydride, trimellitic anhydride, pyromellitic anhydride, trialkyltetrahydrophthalic anhydride maleic adduct, benzophenonetetracarboxylic dianhydride, hydrogenated methylnadic anhydride, dodecenyl succinic anhydride, etc. These may be used individually or in combination of two or more.

[0049] Examples of amines used as curing agents include linear aliphatic amines, cyclic aliphatic amines, fatty aromatic amines, and aromatic amines. Specifically, amines used as curing agents include aromatic amine curing agents with one aromatic ring, such as m-phenylenediamine, 1,3-diaminotoluene, 1,4-diaminotoluene, 2,4-diaminotoluene, 3,5-diethyl-2,4-diaminotoluene, 3,5-diethyl-2,6-diaminotoluene, and 2,4-diaminoanisole; 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 4,4'-methylenebis(2-ethylaniline), and 3,3'-diethyl-4,4'-diaminodiphenylmethane. Examples include aromatic amine curing agents with two aromatic rings, such as tan, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, and 3,3',5,5'-tetraethyl-4,4'-diaminodiphenylmethane; hydrolysis condensates of aromatic amine curing agents; aromatic amine curing agents having a polyether structure, such as polytetramethylene oxide di-p-aminobenzoate and polytetramethylene oxide di-para-aminobenzoate; condensates of aromatic diamines and epichlorohydrins; and reaction products of aromatic diamines and styrene.

[0050] Regarding the mixing ratio of thermosetting resin and curing agent, from the viewpoint of minimizing unreacted portions of each and ensuring sufficient curing reaction, the ratio of the equivalent number of thermosetting functional groups contained in the thermosetting resin to the equivalent number of functional groups contained in the curing agent (equivalent number of thermosetting resin / equivalent number of curing agent) is preferably set in the range of 0.6 to 1.4, more preferably in the range of 0.7 to 1.3, and even more preferably in the range of 0.8 to 1.2. If there are two or more colored layers, it is preferable that the ratio (equivalent amount of thermosetting resin / equivalent amount of curing agent) in each colored layer is within the above range.

[0051] -Curing accelerator- The colored layer may contain a curing accelerator. It is preferable to use various imidazoles as the curing accelerator. Examples of imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, and 2-phenyl-4-methyl-5-hydroxymethylimidazole. Imidazoles are commercially available from Shikoku Chemicals, Inc. under trade names such as 2E4MZ, 2PZ-CN, 2PZ-CNS, and 2P4MHZ-PW. Furthermore, organic phosphine compounds can also be used as curing accelerators. Specific examples of organic phosphine compounds include triphenylphosphine, diphenyl(p-tolyl)phosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, tris(alkylalkoxyphenyl)phosphine, tris(dialkylphenyl)phosphine, tris(trialkylphenyl)phosphine, tris(tetraalkylphenyl)phosphine, tris(dialkoxyphenyl)phosphine, tris(trialkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, trialkylphosphine, dialkylarylphosphine, alkyldiarylphosphine, and the like. When a hardening accelerator is contained in the colored layer, the hardening accelerator content in the colored layer is preferably 0.01% to 10% by mass, more preferably 0.1% to 8% by mass, and even more preferably 0.2% to 6% by mass.

[0052] -Thermoplastic resin- The colored layer may contain a thermoplastic resin. Examples of thermoplastic resins include polyimide resin, (meth)acrylic resin, urethane resin, polyphenylene ether resin, polyetherimide resin, phenoxy resin, modified polyphenylene ether resin, polystyrene resin, polyethylene resin, polyester resin, polyamide resin, butadiene rubber, acrylic rubber, polycarbonate resin, polyphenylene ether resin, and mixtures thereof, but the thermoplastic resin is not limited to these specific examples. When a thermoplastic resin is contained in the colored layer, the content of the thermoplastic resin in the colored layer is preferably 0.1% to 40% by mass, more preferably 0.1% to 30% by mass, even more preferably 0.5% to 30% by mass, even more preferably 0.5% to 20% by mass, particularly preferably 1% to 20% by mass, and extremely preferably 1% to 10% by mass.

[0053] The weight-average molecular weight (Mw) of the thermoplastic resin is preferably 10,000 to 3,000,000, more preferably 50,000 to 2,500,000, and even more preferably 100,000 to 2,000,000. In this disclosure, the weight-average molecular weight is determined by gel permeation chromatography using the following apparatus and measurement conditions, and by conversion using a calibration curve for standard polystyrene. For the preparation of the calibration curve, five sample sets (PStQuick MP-H, PStQuick B [manufactured by Tosoh Corporation, product name]) are used as standard polystyrene. Equipment: High-speed GPC system HLC-8320GPC (Detector: Differential Refractometer) (Manufactured by Tosoh Corporation, product name) Solvent used: Tetrahydrofuran (THF) Column: TSKGEL SuperMultipore HZ-H column (manufactured by Tosoh Corporation, product name) Column size: Column length 15cm, column inner diameter 4.6mm Measurement temperature: 40℃ Flow rate: 0.35mL / min Sample concentration: 10 mg / THF 5 mL Injection volume: 20μL

[0054] -Inorganic filler- The colored layer may contain inorganic fillers. Examples of inorganic fillers include crystalline silica, amorphous silica such as fumed silica, aluminum oxide, calcium carbonate, magnesium carbonate, aluminum nitride, and boron nitride. These inorganic fillers may be used individually or in combination of two or more. Among these, silica fillers such as crystalline silica and amorphous silica are preferred from the viewpoint of versatility. Silica fillers are commercially available from Nippon Aerosil Co., Ltd. under product names such as R972, R972V, and R972CF, from Admatex Co., Ltd. under product names such as SO-E1, SO-E2, SO-E5, SO-C1, SO-C2, SO-C3, and SO-C5, and from Ryumori Co., Ltd. under product names such as PLV-6, PLV-4, TFC-12, TFC-24, USV-5, and USV-10. The average particle size of the inorganic filler is preferably 0.01 μm to 20 μm, more preferably 0.1 μm to 10 μm, and even more preferably 0.2 μm to 2 μm. The inorganic filler may be used alone or in combination of two or more types. From the viewpoint of improving the mechanical properties of the cured film, it is preferable to use two types of inorganic fillers of different sizes in combination, and it is even more preferable to use two types of silica fillers of different sizes in combination. When the colored layer contains an inorganic filler, the inorganic filler content in the colored layer is preferably 1% to 90% by mass, more preferably 5% to 80% by mass, and even more preferably 10% to 70% by mass.

[0055] -Coupling agent- The colored layer may contain a coupling agent. Examples of coupling agents include silane compounds having at least one of a primary amino group, a secondary amino group, and a tertiary amino group, various silane compounds such as epoxysilane, mercaptosilane, alkylsilane, ureidosilane, and vinylsilane (e.g., silane coupling agents listed below), titanium compounds (e.g., titanate coupling agents listed below), aluminum chelates, and aluminum / zirconium compounds.

[0056] Specific examples of coupling agents include vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropylmethyldi Methoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-anilinopropyltrimethoxysilane, γ-anilinopropyltriethoxysilane, γ-(N,N-dimethyl)aminopropyltrimethoxysilane, γ-(N,N-diethyl)aminopropyltrimethoxysilane, γ-(N,N-dibutyl)aminopropyltrimethoxysilane, γ-(N-methyl)anilinopropyltrimethoxysilane, γ-(N-ethyl)anilinopropyltrimethoxysilane, γ-( N,N-dimethyl)aminopropyltriethoxysilane, γ-(N,N-diethyl)aminopropyltriethoxysilane, γ-(N,N-dibutyl)aminopropyltriethoxysilane, γ-(N-methyl)anilinopropyltriethoxysilane, γ-(N-ethyl)anilinopropyltriethoxysilane, γ-(N,N-dimethyl)aminopropylmethyldimethoxysilane, γ-(N,N-diethyl)aminopropylmethyldimethoxysilane, γ-(N,N-dibutyl)aminopropylmethyldimethoxysilane, Silane coupling agents such as γ-(N-methyl)anilinopropylmethyldimethoxysilane, γ-(N-ethyl)anilinopropylmethyldimethoxysilane, N-(trimethoxysilylpropyl)ethylenediamine, N-(dimethoxymethylsilylisopropyl)ethylenediamine, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, vinyltrimethoxysilane, and γ-mercaptopropylmethyldimethoxysilane;Isopropyl triisostearoyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl phosphite) titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, bis(dioctyl pyrophosphate) Examples of titanate coupling agents include ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacrylate isostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl isostearoyl diacrylic titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, and tetraisopropyl bis(dioctyl phosphite) titanate. These coupling agents may be used individually or in combination of two or more. When a coupling agent is contained in the colored layer, the content of the coupling agent in the colored layer is preferably 0.01% to 10% by mass, more preferably 0.05% to 5% by mass, and even more preferably 0.1% to 3% by mass.

[0057] (Other configurations) The base material is the layer that comes into contact with the mold surface, and depending on the material used, a greater peeling force may be required to remove the release film from the mold. When using a base material that is difficult to peel from the mold, it is preferable to adjust it to make it easier to peel the release film from the mold. For example, the surface of the base material opposite to the surface on which the release layer is provided, i.e., the surface of the base material facing the mold, may be given a surface treatment such as a matte finish to improve its release properties from the mold, or a new release layer (second release layer) may be provided. The material of the second release layer is not particularly limited as long as it satisfies the requirements for heat resistance, release properties from the mold, etc., and the same material as the release layer may be used. The average thickness of the second release layer is not particularly limited, but is preferably 0.1 μm to 100 μm.

[0058] Furthermore, if necessary, layers such as an anchoring-enhancing layer (primer layer), an antistatic layer, etc., may be provided between the release layer and the substrate, between the substrate and the second release layer, etc., to improve adhesion between the release layer or the second release layer and the substrate.

[0059] A protective film may be provided on the colored layer of the first release film. Examples of protective films include plastic films such as polytetrafluoroethylene film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, and polyimide film.

[0060] The first release film may optionally have a non-thermosetting colored layer, a metal layer made of metal foil, etc. The non-thermosetting colored layer may be a colored layer obtained by curing a thermosetting colored layer and deactivating its thermosetting properties.

[0061] The second semiconductor encapsulation release film of this disclosure (hereinafter sometimes referred to as the "second release film") comprises a substrate, a release layer, and at least one functional layer in this order, wherein the outermost layer of the functional layer contains a thermosetting resin. The release film has an outermost layer that provides excellent adhesion to the semiconductor package surface. The reason for this is not entirely clear, but it can be inferred as follows: A semiconductor package is manufactured by encapsulating a semiconductor element using an encapsulant while the semiconductor element and the release film are placed in a mold so that the outermost layer, such as the colored layer of the release film, faces each other. When encapsulating the semiconductor element using the encapsulant, a pressurized treatment is performed under predetermined temperature conditions. After the pressurized treatment, the functional layers, including the outermost layer, are transferred to the surface of the encapsulating resin layer that encapsulates the semiconductor element (i.e., the surface of the semiconductor package). Since the outermost layer of the second semiconductor encapsulation release film of this disclosure contains a thermosetting resin, the thermosetting resin in the outermost layer hardens due to the heat generated when encapsulating the semiconductor element. As the thermosetting resin hardens, the outermost layer adheres firmly to the surface of the encapsulant. As a result, it is presumed that the adhesion of the outermost layer to the surface of the semiconductor package will be excellent. "The semiconductor element and the outermost layer of the release film face each other" means that the surface of the outermost layer of the release film on the side with the colored layer faces the semiconductor element. If the surface of the release film is a colored layer, then the semiconductor element and the colored layer of the release film will face each other.

[0062] The second release film of this disclosure comprises a substrate, a release layer, and at least one functional layer, and may optionally have other layers. The following describes the various materials that make up the second release film. Specific examples of the base material and release layer constituting the second release film are the same as those of the base material and release layer constituting the first release film.

[0063] (Functional layer) The second release film has at least one functional layer. The outermost of the at least one functional layer contains a thermosetting resin. The thermosetting resin is preferably an epoxy resin, as described later. If there is one functional layer, that one functional layer contains a thermosetting resin. If there are two or more functional layers, all of the functional layers may contain a thermosetting resin. The functional layer can offer various benefits, including improved strength, heat dissipation, conductivity, visibility, and shielding. The components that make up the functional layer are not particularly limited, as long as they enable the functional layer to exhibit various functions; a combination of various materials used in the relevant technical field can be used. The types of functional layers are not particularly limited and include coloring layers, adhesive layers, shielding layers, heat dissipation layers, etc. For example, the heat dissipation layer may be a metal layer using metal foil such as aluminum foil or copper foil, or a metal particle resin layer containing metal particles in a resin. The shielding layer may be a layer made of metal mesh. Details of the coloring layer and adhesive layer are described below. If the functional layer includes a colored layer, the colored layer may or may not contain a thermosetting resin. In one configuration, the outermost layer of the functional layers is preferably a colored layer. By including a thermosetting resin in the outermost colored layer, it is possible to impart adhesive function to the outermost colored layer. Therefore, it becomes unnecessary to provide an adhesive layer in the second release film, and the layer structure of the second release film can be simplified. In other configurations, the functional layer may include a colored layer and a functional layer different from the colored layer as the outermost layer, in that order from the substrate side. In this case, the functional layer different from the colored layer as the outermost layer contains a thermosetting resin. There may be two or more colored layers. When there are two or more colored layers, it is preferable that the colored layer in contact with the functional layer different from the colored layer contains a thermosetting resin. In this disclosure, "outermost layer" refers to the functional layer that is furthest from the substrate in the thickness direction of the release film. The outermost layer is in direct contact with the encapsulating resin layer of the semiconductor package. In this disclosure, "functional layer" means a layer that is transferred to the surface of the encapsulating resin layer of a semiconductor package.

[0064] A semiconductor package is fabricated by compression molding using a second release film and a semiconductor encapsulating resin containing epoxy resin, under conditions of mold temperature 165°C, molding pressure 6.86 MPa, and molding time 180 seconds, followed by thermal curing at a curing temperature of 175°C, under atmospheric pressure, and for a curing time of 120 minutes. Laser marking is performed on the surface of the functional layer transferred to the semiconductor package under conditions of wavelength 1064 nm, intensity 4 W, scan speed 1000 mm / sec, and Q-switch frequency: 120 kHz. The laser-marked portion of the semiconductor package is cut into 100 squares of 1 mm each. Adhesive tape having adhesive strength compliant with JIS K5600-5-6:1999 is applied to the cut portion. Within 5 minutes after application, the edge of the adhesive tape is grasped and peeled off at an angle of 60° for 0.5 to 1.0 seconds. Preferably, the amount of unpeeled functional layer in the peeled portion is 70 squares or more, more preferably 80 squares or more, and even more preferably 90 squares or more. To ensure that the unpeeled portion consists of 70 or more squares, one possible method is to use epoxy resin as the thermosetting resin included in the outermost layer.

[0065] The storage modulus at 165°C of the cured product obtained by heat-treating the outermost layer under the conditions of a temperature of 165°C, a pressure of 6.86 MPa, and a time of 180 seconds is preferably 0.1 GPa or higher, more preferably 0.3 GPa or higher, and even more preferably 0.5 GPa or higher. When the storage modulus at 165°C of the cured product is 0.1 GPa or higher, the occurrence of adsorption marks during compression molding tends to be suppressed. The storage modulus at 165°C of the cured product may be 1 GPa or less. To achieve a storage modulus of 0.1 GPa or higher at 165°C for a cured product, examples include a method in which the inorganic filler content in the outermost layer is 40% by mass or higher, or a method in which fumed silica with an average primary particle diameter of 10 nm to 50 nm and silica with an average particle diameter of 0.2 μm to 3 μm are used in combination as the inorganic filler.

[0066] -Colored layer- If the functional layer is a colored layer, the colored layer may contain, for example, a colorant, a thermosetting resin, and a curing agent. The colored layer may also contain a curing accelerator, a thermoplastic resin, an inorganic filler, various additives, etc. If there are two or more colored layers, the colorants contained in each colored layer may be the same or different, but it is preferable that they be different.

[0067] From the viewpoint of minimizing the impact on the thickness of the semiconductor package, the average thickness of the colored layer is preferably 1 μm to 100 μm, more preferably 3 μm to 60 μm, and even more preferably 3 μm to 40 μm. If there are two or more colored layers, it is preferable that the average thickness of the entire colored layer falls within the above range.

[0068] The colored layer may contain a coloring agent. Specific examples of coloring agents are the same as the specific examples of coloring agents used in the colored layer constituting the first release film.

[0069] The coloring agent content in the colored layer is preferably 0.1% to 60% by mass, and more preferably 0.5% to 50% by mass. If there are two or more colored layers, it is preferable that the colorant content in each colored layer falls within the above range. The functional layer may comprise two colored layers of different colors. When the functional layer comprises two colored layers of different colors, it is preferable that the combination consists of a colored layer containing a white pigment and a colored layer containing a black pigment. When a colored layer containing white pigment and a colored layer containing black pigment are transferred to the surface of a semiconductor package in that order, irradiating the surface of the semiconductor package with the transferred colored layers with laser light sublimes the resin in the colored layer containing black pigment, making it possible to scrape off the surface of the colored layer. At this time, the colored layer containing white pigment becomes visible where the colored layer containing black pigment has been scraped off, resulting in high-contrast and highly visible printing.

[0070] The colored layer may contain a thermosetting resin. Examples of thermosetting resins include epoxy resins, triazine resins, phenolic resins, melamine resins, cyanate ester resins, and modified versions of these resins. These resins may be used individually or in combination of two or more types. The content of thermosetting resin in the colored layer is the same as that of the colored layer constituting the first release film, and the content of thermosetting resin in each colored layer when there are two or more colored layers is also the same as in the case of the first release film. From the viewpoint of heat resistance, the thermosetting resin is preferably at least one selected from the group consisting of epoxy resins, phenolic resins, and triazine resins, and more preferably an epoxy resin.

[0071] As epoxy resins, difunctional epoxy resins such as bisphenol A type epoxy, novolac type epoxy resins such as phenol novolac type epoxy resins and cresol novolac type epoxy resins can be used. In addition, generally known epoxy resins such as polyfunctional epoxy resins, glycidylamine type epoxy resins, heterocyclic epoxy resins, and alicyclic epoxy resins can be applied. These epoxy resins may be used individually or in combination of two or more types. Specific examples of epoxy resin are the same as the specific examples of epoxy resin given for the colored layer constituting the first release film.

[0072] The epoxy equivalent of the epoxy resin is preferably 80 g / eq to 220 g / eq, more preferably 90 g / eq to 210 g / eq, and even more preferably 100 g / eq to 200 g / eq. The method for measuring the epoxy equivalent of epoxy resin is as described above.

[0073] When the thermosetting resin is an epoxy resin, heterocyclic epoxy resins and alicyclic epoxy resins are preferred, and alicyclic epoxy resins are more preferred from the viewpoint of solubility in solvents and suppression of discoloration of the printed area.

[0074] The colored layer may contain a hardening agent. Specific examples of the hardening agent are the same as the specific examples of the hardening agent used in the colored layer that constitutes the first release film. When the functional layer of the second release film is a colored layer, an acid anhydride is more preferable as the curing agent from the viewpoint of heat resistance and insulation. The mixing ratio of thermosetting resin to curing agent in the second release film is the same as that for the colored layer constituting the first release film, and the mixing ratio when there are two or more colored layers is also the same as that for the first release film.

[0075] As a curing agent, from the viewpoint of suppressing discoloration of the printed area, it is preferable that the curing agent does not contain an aromatic ring in its molecule, more preferably that it is an acid anhydride that does not contain an aromatic ring, and even more preferably that it is hexahydrophthalic anhydride.

[0076] The colored layer may contain a curing accelerator. The curing accelerator is not particularly limited. For example, the curing accelerator may be at least one selected from the group consisting of amine-based curing accelerators, imidazole-based curing accelerators, urea-based curing accelerators, and phosphorus-based curing accelerators. Examples of amine-based curing accelerators include 1,8-diazabicyclo[5.4.0]-7-undecene and 1,5-diazabicyclo[4.3.0]-5-nonene. Examples of imidazole-based curing accelerators include 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, and 2-phenyl-4-methyl-5-hydroxymethylimidazole. Examples of urea-based curing accelerators include 3-phenyl-1,1-dimethylurea. Examples of phosphorus-based curing accelerators include triphenylphosphine and its addition reaction products, diphenyl(p-tolyl)phosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, tris(alkylalkoxyphenyl)phosphine, tris(dialkylphenyl)phosphine, tris(trialkylphenyl)phosphine, tris(tetraalkylphenyl)phosphine, tris(dialkoxyphenyl)phosphine, tris(trialkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, trialkylphosphine, dialkylarylphosphine, alkyldiarylphosphine, (4-hydroxyphenyl)diphenylphosphine, bis(4-hydroxyphenyl)phenylphosphine, tris(4-hydroxyphenyl)phosphine, and the like. In this disclosure, an imidazole-based curing accelerator is preferred from the viewpoint of having a wide variety of derivatives and being able to easily obtain the desired activity temperature.

[0077] Commercially available imidazole-based curing accelerators may be used. Examples include those manufactured by Shikoku Chemicals Co., Ltd., such as "Curezol 2PHZ-PW," "Curezol 2P4MHZ-PW," "Curezol 2E4MZ," "Curezol 2PZ-CN," and "Curezol 2PZ-CNS." If the colored layer contains a curing accelerator, the content of the curing accelerator in the colored layer is the same as the content of the curing accelerator in the colored layer constituting the first release film.

[0078] The colored layer may contain a thermoplastic resin. The inclusion of a thermoplastic resin in the colored layer tends to improve its handling properties when it is uncured. Specific examples of thermoplastic resins, desirable weight-average molecular weight and its measurement method, and content are the same as those for thermoplastic resins used in the colored layer constituting the first release film. From the viewpoint of improving the flexibility and film-forming properties of the colored layer, rubber components such as butadiene rubber and acrylic rubber are preferred, and from the viewpoint of suppressing discoloration of the printed area, acrylic rubber is more preferred.

[0079] The colored layer may contain inorganic fillers. The inclusion of inorganic fillers in the colored layer tends to improve the elastic modulus of the hardened colored layer. Examples of inorganic fillers include barium sulfate, barium titanate, amorphous silica, crystalline silica, amorphous silica, fused silica, spherical silica, aluminum oxide, calcium carbonate, magnesium carbonate, aluminum nitride, boron nitride, silicon nitride, talc, and clay. These inorganic fillers may be used individually or in combination of two or more types. From the viewpoint of easily obtaining improved dispersibility in the resin and suppression of sedimentation in the varnish through surface modification, and from the viewpoint of easily obtaining desired cured film characteristics due to having a relatively small coefficient of thermal expansion, silica fillers such as crystalline silica and amorphous silica are preferred. Specific examples of silica fillers, the average particle size of inorganic fillers, and their content are the same as those for the colored layer constituting the first release film.

[0080] Examples of additives that may be included in the colored layer include release agents, antioxidants, surface tension modifiers, leveling agents, ion exchangers, ion scavenging agents, and coupling agents.

[0081] -Adhesive layer- If the functional layer is an adhesive layer, the adhesive layer may contain, for example, a thermosetting resin and a curing agent. The adhesive layer may also contain a curing accelerator, a thermoplastic resin, an inorganic filler, various additives, etc. The details of the components contained in the adhesive layer are the same as those of the colored layer described above, except for the coloring agent.

[0082] Details of other components such as the second release layer and protective film, which may be provided on the second release film as needed, are the same as in the case of the first release film. Note that the protective film is not transferred to the surface of the encapsulating resin layer of the semiconductor package, and therefore the protective film does not constitute a functional layer.

[0083] (Method for manufacturing release film for semiconductor encapsulation) The first or second release film can be manufactured by known methods. For example, the first or second release film may be manufactured by applying a release layer-forming composition containing components for the release layer to one side of a substrate and drying it to form a release layer on the substrate, and then applying a color layer-forming composition or a functional layer-forming composition containing components for the color layer or functional layer onto the release layer and drying it to form a color layer or functional layer on the release layer. Alternatively, a release layer can be formed on one substrate by applying a release layer-forming composition containing components for the release layer to one side of the substrate and drying it. On the other hand, a colored layer-forming composition or a functional layer-forming composition containing components for the colored layer or functional layer can be applied to one side of another substrate and dried to form a colored layer or functional layer on the other substrate. Then, the two substrates can be bonded together so that the release layer on one substrate and the colored layer or functional layer on the other substrate are in contact, thereby producing a first or second release film. When manufacturing a second release film, a colored layer is formed on one substrate by applying a colored layer-forming composition containing components that constitute the colored layer to one side of a substrate and drying it, thereby obtaining a colored resin film. Next, a functional layer is formed on the other substrate by applying a functional layer-forming composition containing components that constitute the functional layer to one side of another substrate and drying it, thereby obtaining a functional layer resin film. Then, the colored resin film and the functional layer resin film are laminated together using a roll laminator or the like with the colored layer and functional layer in contact, to obtain a colored layer and functional layer resin film in which the colored layer and functional layer are laminated. A second release film may also be manufactured by laminating the colored layer or functional layer in the colored layer and functional layer resin film with the release layer in a release layer-attached film obtained as described above, with the release layer and colored layer or functional layer in contact, using a roll laminator. When manufacturing the second release film, it is preferable to prepare the release layer and the functional layer separately, as this allows the functional layer to be processed into any shape, such as by pre-cutting, and then integrated with the release layer at any desired position, thus enabling its application in various ways. The solvent used in preparing the release layer-forming composition, the colored layer-forming composition, or the functional layer-forming composition is not particularly limited, but is preferably an organic solvent capable of dispersing or dissolving each component constituting the release layer or colored layer. Examples of organic solvents include toluene, methyl ethyl ketone, cyclohexanone, and ethyl acetate. Other substrates may include films that can serve as protective films provided on the colored or functional layers as needed, such as plastic films like polytetrafluoroethylene film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, and polyimide film. Surface treatments such as mold release treatments may also be applied to the surface of other substrates as needed.

[0084] The method for applying the release layer-forming composition, the colored layer-forming composition, or the functional layer-forming composition is not particularly limited, and known coating methods such as the roll coating method, bar coating method, kiss coating method, and comma coating method can be used. The method for drying the applied release layer-forming composition, colored layer-forming composition, or functional layer-forming composition is not particularly limited, and known drying methods can be used. For example, drying at 20°C to 150°C for 0.1 to 60 minutes is also an option. By appropriately adjusting the drying temperature and drying time when drying the colored layer-forming composition, the state in which the colored layer exhibits thermosetting properties can be maintained. The drying temperature and drying time of the colored layer-forming composition can be appropriately set in consideration of the type and amount of components contained in the colored layer-forming composition.

[0085] <Marking film for semiconductor encapsulation> The semiconductor encapsulation marking film of this disclosure has a thermosetting colored layer. The details of the colored layer included in the semiconductor encapsulation marking film are the same as those of the colored layer included in the first release film, and the range of materials, composition, thickness, etc. used in the colored layer are also the same. One form of the semiconductor encapsulation marking film may have a substrate and a thermosetting colored layer in that order. Another method for manufacturing a semiconductor encapsulation marking film is to apply a colored layer-forming composition to one side of a substrate and dry it. This forms a semiconductor encapsulation marking film on the substrate. The method of applying the colored layer-forming composition, the drying method of the colored layer-forming composition, and other conditions, as well as the type of substrate, are the same as those for the first method of manufacturing a release film. The semiconductor encapsulation marking film of this disclosure may further have a functional layer different from the colored layer. Details of the functional layer are as previously described.

[0086] <Semiconductor package and method for manufacturing the same> The first semiconductor package of this disclosure comprises a semiconductor element, a sealing resin layer that seals the semiconductor element, and a colored layer provided on the surface of the sealing resin layer, wherein the colored layer is a layer derived from the colored layer of the first release film of this disclosure. The second semiconductor package of this disclosure comprises a semiconductor element, a sealing resin layer for sealing the semiconductor element, and a functional layer provided on the surface of the sealing resin layer, wherein the functional layer is a layer derived from the functional layer of the second release film of this disclosure. Since the outermost layer of the functional layer of the second release film of this disclosure contains a thermosetting resin, when a semiconductor element is heated and pressurized using a sealing resin to seal it, the outermost layer of the functional layer undergoes a thermosetting reaction and hardens. As a result, the hardened outermost layer (i.e., the layer derived from the functional layer) can adhere firmly to the sealing resin layer. Therefore, it is presumed that the adhesion of the outermost layer to the semiconductor package surface is improved.

[0087] The first or second semiconductor package of this disclosure may be manufactured by any method. The first or second semiconductor package of this disclosure may be manufactured, for example, by a process of sealing a semiconductor element while the semiconductor element and the first or second release film are placed in a mold such that the semiconductor element and the first or second release film face each other. Conventional solid or liquid sealing materials can be used as the sealing material used in the process of sealing the semiconductor element. In the first semiconductor package, laser marking may be applied to the colored layer after the semiconductor element has been sealed. Furthermore, in the second semiconductor package, if the functional layer includes a colored layer, laser marking may be applied to the colored layer after the semiconductor element has been sealed. In the process of encapsulating the semiconductor element, the semiconductor element may be encapsulated by compression molding or transfer molding, and compression molding is preferred.

[0088] Typically, in the compression molding of semiconductor packages, a release film is placed in the mold of the compression molding apparatus, and the release film is made to conform to the shape of the mold by vacuum suction or the like. Then, the encapsulant for the semiconductor package (e.g., epoxy resin) is placed in the mold, the semiconductor elements are placed on top, and the encapsulant is hardened by compressing the mold while heating, thereby molding the semiconductor package. After that, the mold is opened and the molded semiconductor package is removed. In this way, semiconductor packages can be manufactured. At this time, the colored layer (or functional layer) of the release film is transferred to the surface of the encapsulating resin layer of the semiconductor package. The thermosetting resin contained in the colored layer (or functional layer) preferably contains epoxy resin. Since the encapsulating material of semiconductor packages often contains epoxy resin, including epoxy resin as the thermosetting resin in the colored layer (or the outermost layer of the functional layer) tends to improve the adhesion between the encapsulating resin layer and the colored layer (or the outermost layer). Therefore, the occurrence of wrinkles and other defects in the colored layer is more easily suppressed, resulting in a superior appearance of the semiconductor package surface. In addition, the adhesion of the outermost layer to the semiconductor package surface tends to improve. [Examples]

[0089] The present disclosure will be described below based on examples, but the present disclosure is not limited to the following examples. In the following examples, parts and % refer to parts by mass and mass %, respectively, unless otherwise specified.

[0090] [Example 1A] (Preparation of release film) A primer layer solution with a solid content of 1% was prepared by mixing 65 parts of acrylic resin (monomer components: ethyl acrylate, butyl acrylate, and acrylonitrile), 35 parts of tin catalyst (dinor octyl tin dilaurate), and toluene. Next, a release layer solution with a solid content of 15% was prepared by mixing 100 parts of acrylic resin (monomer component: alkyl acrylate), 17 parts of polyisocyanate as a crosslinking agent, 10 parts of filler (acrylic resin particles, average particle size: 10 μm), and toluene. As a substrate, a biaxially oriented polyethylene terephthalate film with an average thickness of 25 μm was coated on one side using a roll coater with the primer layer solution. Then, the release layer solution was applied in layers and dried to form a release layer, resulting in an average thickness of 10 μm after drying, and a release film was obtained. The drying temperature was 100°C and the drying time was 2 minutes.

[0091] (Preparation of colored resin film) A colored layer-forming composition with a solid content of 35.0% was prepared by mixing 15 parts of an acrylic ester polymer (monomer components: butyl acrylate and acrylonitrile, weight-average molecular weight: 900,000), 54 parts of epoxy resin (alicyclic epoxy resin, epoxy equivalent: 175 g / eq), 46 parts of an acid anhydride curing agent (hexahydrophthalic anhydride), 21 parts of carbon black (average particle size: 0.5 μm), 5 parts of a curing accelerator (2-phenyl-4-methyl-5-hydroxymethylimidazole), 140 parts of silica filler (average particle size: 0.5 μm), and methyl ethyl ketone.

[0092] This colored layer-forming composition was applied to a polyethylene terephthalate film with a thickness of 38 μm using a comma coater, and then dried at 80°C for 5 minutes to produce a colored resin film having a colored layer with an average thickness of 10 μm.

[0093] (Preparation of release film with integrated colored layer) The release film and the colored resin film obtained as described above were laminated together using a roll laminator with the release layer and the colored layer in contact, to produce a release film with an integrated colored layer. The conditions for the roll laminator were as follows. Lamination pressure: 0.4 MPa Laminating temperature: 80℃ Laminating speed: 2m / min

[0094] (Compression molding process) A semiconductor bare chip was set in the upper mold of a compression molding die, and a release film with an integrated colored layer was attached to the lower mold. The polyethylene terephthalate film on the colored layer was peeled off, and the semiconductor bare chip and the colored layer of the release film were positioned so that they faced each other. A encapsulant (manufactured by Showa Denko Materials Co., Ltd.: product name "CEL-9750ZHF10") was supplied onto the release film with an integrated colored layer. After fixing the release film with an integrated colored layer to the lower mold of the compression molding die under vacuum, the mold was clamped, and the encapsulant was molded (compression molding) to obtain a semiconductor package. The mold temperature was 165°C, and the molding pressure was 6.86 MPa (70 kgf / cm²). 2 The molding time was set to 180 seconds.

[0095] (hardening) Next, the semiconductor package was heat-cured. The curing temperature was 175°C, under atmospheric pressure, and the curing time was 120 minutes.

[0096] (Laser marking) The semiconductor package was marked with characters (120 characters in a 10mm x 11mm cell, the characters are not particularly limited) and rectangles (15mm x 15mm). The laser marking conditions are as follows. Laser marking device: Product name "MD-S9900", manufactured by Keyence Corporation. Wavelength: 1064nm Strength: 4W Scanning speed: 1000mm / sec Q-switch frequency: 120kHz

[0097] [Example 2A] A release film with an integrated colored layer was prepared in the same manner as in Example 1A, except that the drying conditions after applying the colored layer-forming composition onto a polyethylene terephthalate film with a comma coater were changed to 10 minutes at 100°C. A semiconductor package was fabricated using the obtained release film with an integrated colored layer by compression molding, and laser marking was performed in the same manner as in Example 1A.

[0098] [Example 3A] A release film with an integrated colored layer was prepared in the same manner as in Example 1A, except that the drying conditions after applying the colored layer-forming composition onto a polyethylene terephthalate film with a comma coater were changed to 120°C for 10 minutes. A semiconductor package was fabricated using the obtained release film with an integrated colored layer by compression molding, and laser marking was performed in the same manner as in Example 1A.

[0099] [Comparative Example 1A] A release layer from the release film used in Example 1A and a colored layer from the colored resin film used in Example 1A, heated at 175°C for 2 hours to reach the C stage (cured state), were prepared. With the release layer of the release film and the colored layer of the colored resin film in contact, the two were laminated together using a roll laminator under the same conditions as in Example 1A to produce a release film with an integrated colored layer. A semiconductor package was fabricated by compression molding using the obtained release film with an integrated colored layer, and laser marking was performed in the same manner as in Example 1A.

[0100] [Comparative example 2A] A release film with an integrated colored layer was fabricated by laminating the release film used in Example 1A with a commercially available acrylic resin-based laser marking label. A semiconductor package was fabricated using the obtained integrated colored layer release film by compression molding, and laser marking was performed in the same manner as in Example 1A.

[0101] [Evaluation Method] The following evaluations were performed using the obtained colored layer integrated release film and semiconductor package.

[0102] (Heat generation from the colored layer) The heat generated by the colored layer was measured using the following method. A portion of the colored layer in a release film with an integrated colored layer was scraped off with a spatula to obtain the colored layer to be measured. 10 mg of the colored layer to be measured was placed in a differential scanning calorimeter (product name: DSC Q1000, manufactured by T.A. Instruments Corporation) and heated from room temperature (25°C) to 300°C at a heating rate of 5°C / min to obtain a DSC curve during the heating process. The exothermic peak appearing in the obtained DSC curve was defined as the exothermic peak of the colored layer determined by differential scanning calorimetry. Furthermore, the heat generation amount of the exothermic peak was calculated from the area of ​​the exothermic peak appearing in the DSC curve.

[0103] (Surface appearance) The presence or absence of wrinkles on the surface of the colored layer transferred after molding was visually evaluated. A: Good appearance (no wrinkles) B: Cosmetic defects (wrinkles present)

[0104] (Heat resistance) The presence or absence of delamination of the colored layer on the semiconductor package after thermal curing was observed and evaluated visually and under a microscope. A: No peeling B: Peeling present

[0105] (Adhesion) The surface of a heat-cured semiconductor package, before laser marking, was cut into 100 squares of 1 mm each using a guide jig and cutter. Transparent tape with adhesive strength conforming to JIS K5600-5-6:1999 (e.g., LP18 and LP24, manufactured by Nichiban Co., Ltd.) was applied to the cut areas. Within 5 minutes of application, the tape was peeled off at an angle of approximately 60° and at a speed of approximately 0.5 to 1.0 seconds. After peeling, the presence or absence of delamination of the colored layer was visually observed and evaluated. A: No peeling (100 / 100) B: Peeling present

[0106] [Table 1]

[0107] [Example 4A] (Preparation of colored cured resin film) A colored cured layer-forming composition with a solid content of 38.0% was prepared by mixing 41 parts of an acrylic ester polymer (monomer components: butyl acrylate and acrylonitrile, weight-average molecular weight: 900,000), 54 parts of an epoxy resin (alicyclic epoxy resin, epoxy equivalent: 175 g / eq), 46 parts of an acid anhydride-based curing agent (hexahydrophthalic anhydride), 105 parts of a white pigment (titanium dioxide, average particle size: 0.4 μm), 5 parts of a curing accelerator (2-phenyl-4-methyl-5-hydroxymethylimidazole), 14 parts of a silica filler (average particle size: 0.5 μm), and methyl ethyl ketone.

[0108] This colored cured layer-forming composition was applied to a polyethylene terephthalate film with a thickness of 38 μm using a comma coater, dried at 80°C for 5 minutes, and then heated at 175°C for 2 hours to reach the C stage (cured state), thereby producing a colored cured resin film having a colored cured layer with an average thickness of 10 μm.

[0109] (Preparation of colored layer and colored cured layer resin film) The colored resin film and the colored cured resin film of Example 1A were laminated together using a roll laminator at 80°C and 0.4 MPa with the colored layer and the colored cured layer in contact, thereby producing a colored layer and colored cured layer resin film in which the colored layer and the colored cured layer were laminated.

[0110] (Preparation of release film with integrated colored layer) The polyethylene terephthalate film on the colored layer of the colored layer and colored cured layer resin film was removed. Next, the release film obtained in Example 1A and the colored layer and colored cured layer resin film were laminated together using a roll laminator with the release layer and colored layer in contact, to produce a release film with an integrated colored layer. The conditions of the roll laminator were the same as in Example 1A. A semiconductor package was fabricated by compression molding using the obtained colored layer integrated release film, and laser marking was performed in the same manner as in Example 1A.

[0111] [Example 5A] Instead of a colored curing resin film, a 12 μm thick copper foil was used. The colored layer of the colored resin film in Example 1A and the copper foil were in contact and laminated together using a roll laminator at 80°C and 0.4 MPa to produce a colored layer and copper foil film in which the colored layer and copper foil were laminated. The polyethylene terephthalate film on the colored layer and the copper foil film was removed. Next, the release film obtained in Example 1A, the colored layer, and the copper foil film were laminated together using a roll laminator with the release layer and the colored layer in contact, to produce a release film with an integrated colored layer. The conditions of the roll laminator were the same as in Example 1A. A semiconductor package was fabricated by compression molding using the obtained colored layer integrated release film, and laser marking was performed in the same manner as in Example 1A.

[0112] The semiconductor packages obtained in Examples 4A and 5A were evaluated for their surface appearance in the same manner as in Example 1A. Furthermore, the heat generated by the colored layer-integrated release films of Examples 4A and 5A was measured in the same manner as in Example 1A. Furthermore, the presence or absence of delamination between the heat-cured colored hardened layer (Example 4A) or copper foil (Example 5A) and the sealing resin layer of the semiconductor package was observed visually and under a microscope, and the heat resistance was measured in the same manner as in Example 1A. A: No peeling B: Peeling present

[0113] [Table 2]

[0114] [Example 1B] (Preparation of release film) A release film was obtained in the same manner as in Example 1A.

[0115] (Preparation of colored resin film) A colored layer-forming composition was prepared in the same manner as in Example 1A.

[0116] This colored layer-forming composition was applied to a polyethylene terephthalate film with a thickness of 38 μm using a comma coater, and then dried at 85°C for 2 minutes to produce a colored resin film having a colored layer with an average thickness of 10 μm.

[0117] (Preparation of release film with integrated colored layer) The release film and the colored resin film obtained as described above were laminated together using a roll laminator under the same conditions as in Example 1A, with the release layer and the colored layer in contact, to produce a release film with an integrated colored layer.

[0118] (Compression molding process) A semiconductor package was obtained by performing a compression molding process in the same manner as in Example 1A.

[0119] (hardening) Next, the semiconductor package was heat-cured. The curing temperature was 175°C, under atmospheric pressure, and the curing time was 300 minutes.

[0120] [Comparative example 1B] A release layer of the release film used in Example 1B and a colored resin film used in Example 1B, heated at 140°C for 2 hours to reach the C stage (cured state), were brought into contact and laminated using a roll laminator under the same conditions as in Example 1B to produce a release film with an integrated colored layer. A semiconductor package was fabricated by compression molding using the obtained release film with an integrated colored layer.

[0121] [Comparative Example 2B] A release film with an integrated colored layer was fabricated by laminating the release film used in Example 1B with a commercially available acrylic resin-based laser marking label. A semiconductor package was fabricated using the obtained integrated colored layer release film by compression molding.

[0122] (Evaluation method) The heat resistance and adhesion of the heat-cured semiconductor package were evaluated in the same manner as in Example 1A.

[0123] [Table 3]

[0124] From the evaluation results of Example 1B and Comparative Examples 1B and 2B in Table 3, it can be seen that the second semiconductor encapsulation release film of the present disclosure, which has a functional layer containing a thermosetting resin in its outermost layer, exhibits excellent adhesion to the semiconductor package surface.

[0125] [Example 2B] A release film was obtained in the same manner as in Example 1B. A colored resin film was obtained in the same manner as in Example 1B, except that the drying conditions after applying the colored layer-forming composition with a comma coater were set to 80°C for 5 minutes.

[0126] (Fabrication of functional layer resin film) A functional layer-forming composition with a solid content of 38.0% was prepared by mixing 41 parts of an acrylic ester polymer (monomer components: butyl acrylate and acrylonitrile, weight-average molecular weight: 900,000), 54 parts of an epoxy resin (alicyclic epoxy resin, epoxy equivalent: 175 g / eq), 46 parts of an acid anhydride curing agent (hexahydrophthalic anhydride), 105 parts of a white pigment (titanium dioxide, average particle size: 0.4 μm), 5 parts of a curing accelerator (2-phenyl-4-methyl-5-hydroxymethylimidazole), 14 parts of a silica filler (average particle size: 0.5 μm), and methyl ethyl ketone.

[0127] A functional layer resin film having a functional layer with an average thickness of 10 μm was prepared by applying this functional layer-forming composition onto a polyethylene terephthalate film with a thickness of 38 μm using a comma coater, and then drying it at 80°C for 5 minutes.

[0128] (Preparation of colored layer and functional layer resin film) The above-mentioned colored resin film and the functional layer resin film were laminated together using a roll laminator under the same conditions as in Example 1A, with the colored layer and the functional layer in contact, to produce a colored layer and functional layer resin film in which the colored layer and the functional layer were laminated.

[0129] (Fabrication of release films for semiconductor encapsulation) The polyethylene terephthalate film on the colored layer of the colored layer and functional layer resin film was removed. Next, the release film obtained as described above and the colored layer and functional layer resin film were laminated using a roll laminator with the release layer and colored layer in contact to produce a release film for semiconductor encapsulation. The conditions of the roll laminator were the same as in Example 1A.

[0130] (Compression molding process) A bare semiconductor chip was set in the upper mold of a compression molding die, and a release film for semiconductor encapsulation was attached to the lower mold. The polyethylene terephthalate film on the functional layer was peeled off, and the bare semiconductor chip and the functional layer of the release film for semiconductor encapsulation were positioned facing each other. Encapsulation material (manufactured by Showa Denko Materials Co., Ltd.: product name "CEL-9750ZHF10") was supplied onto the release film for semiconductor encapsulation. After fixing the release film for semiconductor encapsulation to the lower mold of the compression molding die under vacuum, the mold was clamped, and the encapsulation material was molded (compression molding) to obtain a semiconductor package. The mold temperature was 165°C, and the molding pressure was 6.86 MPa (70 kgf / cm²). 2 The molding time was set to 180 seconds.

[0131] (hardening) Next, the semiconductor package was heat-cured. The curing temperature was 175°C, under atmospheric pressure, and the curing time was 120 minutes. Then, the semiconductor package was laser-marked in the same manner as in Example 1A.

[0132] [Example 3B] A semiconductor encapsulation release film was prepared in the same manner as in Example 2B, except that the drying conditions after applying the colored layer-forming composition and the functional layer-forming composition onto a polyethylene terephthalate film with a comma coater were changed to 10 minutes at 100°C. A semiconductor package was prepared by compression molding using the obtained semiconductor encapsulation release film, and laser marking was performed in the same manner as in Example 2B.

[0133] [Example 4B] A semiconductor encapsulation release film was prepared in the same manner as in Example 2B, except that the drying conditions after applying the colored layer-forming composition and the functional layer-forming composition onto a polyethylene terephthalate film with a comma coater were changed to 120°C for 10 minutes. A semiconductor package was prepared by compression molding using the obtained semiconductor encapsulation release film, and laser marking was performed in the same manner as in Example 2B.

[0134] [Example 5B] A semiconductor encapsulation release film was prepared in the same manner as in Example 2B, except that the colored resin film used in Example 2B was changed to a colored layer that had been heated at 175°C for 2 hours to reach the C stage (cured state). A semiconductor package was fabricated using the obtained semiconductor encapsulation release film by compression molding, and laser marking was performed in the same manner as in Example 2B.

[0135] [Comparative example 3B] The colored layer and functional layer resin film used in Example 2B were heated at 175°C for 2 hours to prepare the colored layer and functional layer in the C stage (cured state). With the release layer of the release film and the colored layer of the colored layer and functional layer resin film in contact, the two were laminated together using a roll laminator under the same conditions as in Example 2B to produce a semiconductor encapsulation release film. A semiconductor package was fabricated by compression molding using the obtained semiconductor encapsulation release film, and laser marking was performed in the same manner as in Example 2B.

[0136] [Comparative example 4B] The colored layer and copper foil film obtained in Example 5A were heated at 175°C for 2 hours to bring the colored layer to the C stage (cured state). With the release layer of the release film and the colored layer and copper foil film in contact, the two were laminated together using a roll laminator under the same conditions as in Example 2B to produce a semiconductor encapsulation release film. A semiconductor package was fabricated by compression molding using the obtained semiconductor encapsulation release film, and laser marking was performed in the same manner as in Example 2B.

[0137] [Comparative Example 5B] The colored layer-integrated release film of Comparative Example 2B was used as the semiconductor encapsulation release film of Comparative Example 5B, and a semiconductor package was fabricated by compression molding. Laser marking was then performed in the same manner as in Example 2B.

[0138] [Evaluation Method] The following evaluations were performed using the obtained semiconductor encapsulation release film and semiconductor package. Adhesion was evaluated in the same manner as in Example 1A.

[0139] (Heat generation) The heat generated by the colored layer and the functional layer was measured using the same method as in Example 1A.

[0140] (Heat resistance) The presence or absence of delamination between the functional layer of the thermally cured semiconductor package and the sealing resin layer of the semiconductor package was observed and evaluated visually and under a microscope. A: No peeling B: Peeling present

[0141] [Table 4]

[0142] [Example 6B] (Preparation of release film) A release film was prepared in the same manner as in Example 1A.

[0143] (Preparation of colored resin film) A colored layer-forming composition with a solid content of 35.0% was prepared by mixing an acrylic ester polymer (monomer components: butyl acrylate and acrylonitrile, weight-average molecular weight 900,000), an epoxy resin (alicyclic epoxy resin, epoxy equivalent: 175 g / eq), an acid anhydride curing agent (hexahydrophthalic anhydride), carbon black (average particle size: 0.5 μm), a curing accelerator (2-phenyl-4-methyl-5-hydroxymethylimidazole), a silica filler (average particle size: 0.5 μm), and methyl ethyl ketone. The formulation is as shown in Table 5 (unit: parts by mass).

[0144] This colored layer-forming composition was applied to a polyethylene terephthalate film with a thickness of 38 μm using a comma coater, and then dried at 85°C for 2 minutes to produce a colored resin film with an average thickness of 10 μm.

[0145] (Preparation of release film with integrated colored layer) The release film and the colored resin film obtained as described above were laminated together using a roll laminator under the same conditions as in Example 1A, with the release layer and the colored layer in contact, to produce a release film with an integrated colored layer.

[0146] (Compression molding process) A semiconductor package was obtained under the same conditions as in Example 1A, except that the molding time was set to three conditions: 90 seconds, 120 seconds, or 180 seconds.

[0147] [Examples 7B and 8B] Using the colored resin film prepared by blending each component according to the formulations shown in Table 5 (unit: parts by mass), a colored layer-integrated release film was prepared in the same manner as in Example 6B, and a semiconductor package was obtained by compression molding under the same conditions as in Example 6B.

[0148] [Table 5]

[0149] -Storage modulus- The colored resin film obtained as described above was heat-treated at a temperature of 165°C, a pressure of 6.86 MPa, and a time of 180 seconds to obtain a sample for measuring the storage modulus. Viscoelasticity measurements were performed in tensile mode using a dynamic viscoelasticity analyzer, RSA GII (manufactured by TA instruments). The measurement conditions were a heating rate of 10°C / min, a temperature range of 0°C to 300°C, a frequency of 10 Hz, and a strain of 0.1%, and the storage modulus at 165°C was measured.

[0150] -exterior- The surface of semiconductor packages fabricated by compression molding was visually observed and evaluated. A: No adhesive marks B: Slight adhesive marks present C: Uneven surface due to adsorption Adhesion evaluation was performed in the same manner as in Example 1A, using a sample obtained by thermal curing a semiconductor package, which was molded in a compression molding process under conditions of a molding time of 180 seconds, at 175°C, atmospheric pressure, and a curing time of 120 minutes.

[0151] [Table 6]

[0152] [Example 9B] (Preparation of release film) A release film was prepared in the same manner as in Example 1A.

[0153] (Preparation of colored resin film) A colored layer-forming composition was prepared in the same manner as in Example 1A.

[0154] This colored layer-forming composition was applied to a polyethylene terephthalate film with a thickness of 38 μm using a comma coater, and then dried at 80°C for 3 minutes to produce a colored resin film having a colored layer with an average thickness of 10 μm.

[0155] (Preparation of release film with integrated colored layer) The release film and the colored resin film obtained as described above were laminated together using a roll laminator with the release layer and the colored layer in contact, to produce a release film with an integrated colored layer. The conditions for the roll laminator were the same as in Example 1A.

[0156] (Compression molding process) A semiconductor package was obtained under the same conditions as in Example 1A.

[0157] (hardening) Next, the semiconductor package was heat-cured. The curing temperature was 175°C, under atmospheric pressure, and the curing time was 120 minutes. Then, the semiconductor package was laser-marked in the same manner as in Example 1A.

[0158] [Example 10B] A release film with an integrated colored layer was prepared in the same manner as in Example 9B, except that the colored resin film used in Example 9B was heated for an additional 10 minutes at 120°C. A semiconductor package was fabricated using the obtained release film with an integrated colored layer by compression molding, and laser marking was performed in the same manner as in Example 9B.

[0159] [Comparative Example 6B] In Example 9B, the release layer of the release film used in Example 9B and the colored resin film used in Example 9B, which had been heated at 140°C for 2 hours to reach the C stage (cured state), were in contact with each other. Under the same conditions as in Example 9B, the release film and the colored resin film were laminated together using a roll laminator to produce a release film with an integrated colored layer. Using the obtained release film with an integrated colored layer, a semiconductor package was fabricated by compression molding, and laser marking was performed in the same manner as in Example 9B.

[0160] [Comparative Example 7B] A release film with an integrated colored layer was fabricated by laminating the release film used in Example 9B with a commercially available acrylic resin-based laser marking label. A semiconductor package was fabricated using the obtained integrated colored layer release film, and laser marking was performed in the same manner as in Example 9B.

[0161] [Evaluation Method] The following evaluations were performed using the obtained semiconductor packages. The heat generated by the colored layer was measured in the same manner as in Example 1A. The heat resistance was evaluated in the same manner as in Example 1B.

[0162] (Adhesion after laser marking) The adhesion to the surface of the semiconductor package after laser marking was evaluated in the same manner as in Example 1A. The table shows the number of squares remaining on the surface of the semiconductor package after tape removal.

[0163] [Table 7]

[0164] The disclosures of Japanese Patent Application No. 2020-056782, filed on 26 March 2020, and International Patent Application No. PCT / JP2020 / 013792, filed on 26 March 2020, are incorporated herein by reference in their entirety. All documents, patent applications, and technical standards described herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted as being incorporated by reference.

Claims

1. A release film for semiconductor encapsulation, comprising a base material, a release layer, and a thermosetting colored layer in that order.

2. The semiconductor encapsulation release film according to claim 1, wherein the colored layer contains a coloring agent, a thermosetting resin, and a curing agent.

3. The semiconductor encapsulation release film according to claim 2, wherein the thermosetting resin includes an epoxy resin.

4. The semiconductor encapsulation release film according to any one of claims 1 to 3, wherein the substrate comprises a polyester resin.

5. The semiconductor encapsulation release film according to any one of claims 1 to 4, wherein the colored layer is transferred to the surface of the encapsulation resin layer of the semiconductor package.

6. A release film for semiconductor encapsulation, comprising a base material, a release layer, and at least one functional layer in this order, wherein the outermost of the functional layers contains a thermosetting resin.

7. The semiconductor encapsulation release film according to claim 6, wherein the functional layer is transferred to the surface of the encapsulation resin layer of the semiconductor package.

8. A semiconductor package is manufactured by compression molding using the aforementioned semiconductor encapsulation release film and a semiconductor encapsulation resin containing epoxy resin, under the conditions of a mold temperature of 165°C, a molding pressure of 6.86 MPa, and a molding time of 180 seconds, followed by thermal curing at a curing temperature of 175°C, under atmospheric pressure, and for a curing time of 120 minutes. Laser marking is performed on the surface of the functional layer transferred to the semiconductor package under the conditions of wavelength 1064 nm, intensity 4 W, scan speed 1000 mm / sec, and Q-switch frequency: 120 kHz. The release film for semiconductor encapsulation according to claim 6 or claim 7, wherein the laser-marked portion of the semiconductor package is cut into 100 squares of 1 mm each, an adhesive tape having adhesive strength compliant with JIS K5600-5-6:1999 is applied to the cut portion, and within 5 minutes after application, the end of the adhesive tape is grasped and the adhesive tape is peeled off at an angle of 60° for 0.5 to 1.0 seconds, and the remaining unpeeled portion of the functional layer in the peeled portion is 70 squares or more.

9. The semiconductor encapsulation release film according to any one of claims 6 to 8, wherein the functional layer includes a colored layer.

10. The semiconductor encapsulation release film according to claim 9, wherein the functional layer comprises the colored layer and a functional layer different from the colored layer as the outermost layer, in this order from the substrate side.

11. The release film for semiconductor encapsulation according to any one of claims 6 to 10, wherein the thermosetting resin comprises an epoxy resin.

12. The semiconductor encapsulation release film according to any one of claims 9 to 11, wherein the colored layer contains a coloring agent, a thermosetting resin, and a curing agent.

13. The semiconductor encapsulation release film according to claim 12, wherein the thermosetting resin contained in the colored layer includes an epoxy resin.

14. The semiconductor encapsulation release film according to any one of claims 6 to 13, wherein the substrate comprises a polyester resin.

15. The semiconductor encapsulation release film according to any one of claims 6 to 14, wherein the storage modulus at 165°C of the cured product obtained by heat-treating the outermost layer under the conditions of a temperature of 165°C, a pressure of 6.86 MPa, and a time of 180 seconds is 0.1 GPa or more.

16. The semiconductor encapsulation release film according to any one of claims 6 to 15, wherein the outermost layer contains an inorganic filler, and the amount of the inorganic filler is 40% by mass or more based on the total mass of the outermost layer.

17. A semiconductor package comprising a semiconductor element, a sealing resin layer for sealing the semiconductor element, and a colored layer provided on the surface of the sealing resin layer, wherein the colored layer is a layer derived from the colored layer of the semiconductor encapsulation release film described in any one of claims 1 to 5.

18. A semiconductor package comprising a semiconductor element, a sealing resin layer for sealing the semiconductor element, and a functional layer provided on the surface of the sealing resin layer, wherein the functional layer is a layer derived from the functional layer of the semiconductor encapsulation release film described in any one of claims 6 to 16.

19. A method for manufacturing a semiconductor package, comprising the step of sealing a semiconductor element while arranging the semiconductor element and the semiconductor encapsulation release film in a mold such that the semiconductor element and the colored layer side of the semiconductor encapsulation release film described in any one of claims 1 to 5 face each other.

20. A method for manufacturing a semiconductor package, comprising the step of sealing a semiconductor element while arranging the semiconductor element and the semiconductor encapsulation release film in a mold such that the semiconductor element and the outermost layer of the semiconductor encapsulation release film described in any one of claims 6 to 16 face each other.

21. A marking film for semiconductor encapsulation having a thermosetting colored layer.

22. The semiconductor encapsulation marking film according to claim 21, further comprising a functional layer different from the colored layer.

Images