Marking film for semiconductor encapsulation, release film for semiconductor encapsulation, semiconductor package, and method for manufacturing semiconductor package

Abstract

The present invention provides a semiconductor encapsulation marking film, a semiconductor encapsulation release film, a semiconductor package, and a semiconductor package manufacturing method characterized by comprising two types of colored layers with different colors, one of the colored layers being a white colored layer that is stacked on an encapsulant layer surface and has a transmittance of 0.22 or less for a light with a wavelength of 1064 nm.

Description

Technical Field

[0001] The present disclosure relates to a marking film for semiconductor encapsulation, a release 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. Further, in the semiconductor package described above, the semiconductor element is encapsulated with a thermosetting resin encapsulant, and as the semiconductor package becomes thinner, the encapsulation resin layer for encapsulating the semiconductor element is also becoming thinner.

[0003] In a resin-encapsulated semiconductor package, various identification information such as a manufacturing lot number and a logo mark is printed on the surface of the encapsulation resin layer. As one of the printing methods on 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 processes 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 may be used in which printing is performed by removing the surface of the encapsulation resin layer with a laser. 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 printed portion is improved.

[0005] In addition, a sealing sheet having good laser markability has been proposed (see, for example, Patent Documents 1 and 2). The sealing sheets described in Patent Documents 1 and 2 have a resin layer excellent in laser markability and an encapsulation resin layer for encapsulating a semiconductor element laminated thereon.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] Since the encapsulation resin layer that encapsulates the semiconductor element is located on the outermost layer of the semiconductor package, an excellent appearance is required. On the other hand, since the encapsulation resin layer generally contains a large amount of filler, the addition amount of the colorant may be small. In addition, since carbon black widely used as a colorant exhibits conductivity, it may not be possible to add it at a high concentration in the encapsulation resin layer from the viewpoint of reliability. For these reasons, the blackness of the encapsulation resin layer may be insufficient, resulting in a poor appearance of the semiconductor package. In addition, the encapsulation sheet disclosed in Patent Documents 1 and 2 has a structure in which a resin layer excellent in laser marking property and an encapsulation resin layer that encapsulates the semiconductor element are laminated as described above. Therefore, the types of encapsulants are limited to the materials that constitute the encapsulation resin layer. As a result, the degree of freedom in the selection of the encapsulant is inferior. Furthermore, when a coloring layer excellent in laser marking property is disposed on the surface of the encapsulation resin layer to improve the appearance of the semiconductor package, peeling may occur at the interface between the coloring layer and the encapsulation resin layer in the marked portion due to printing.

[0008] One aspect of the present disclosure has been made in view of the above-described circumstances of the prior art, and an object thereof is to provide a marking film for semiconductor encapsulation that can suppress peeling of the coloring layer. Another aspect of the present disclosure is to provide a release film for semiconductor encapsulation capable of suppressing peeling of the coloring layer, a semiconductor package using this release film for semiconductor encapsulation, and a method for manufacturing a semiconductor package.

Means for Solving the Problems

[0009] Specific means for achieving the above problems are as follows. <1>A semiconductor encapsulation marking film comprising two types of colored layers with different colors, wherein one of the colored layers is laminated on the surface of a semiconductor encapsulant layer and is a white colored layer having a light transmittance of 0.22 or less at a wavelength of 1064 nm. <2>The semiconductor encapsulation marking film according to <1>, wherein the colored layer contains a coloring agent, a thermosetting resin, and a curing agent. <3>A release film for semiconductor encapsulation, in which a base material, a release layer, and the semiconductor encapsulation marking film according to <1> are laminated in this order. <4>A release film for semiconductor encapsulation, in which a base material, a release layer, and the semiconductor encapsulation marking film according to <2> are laminated in this order. <5>A semiconductor package, in which 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 are the colored layers of the release film for semiconductor encapsulation according to <3> or <4>. <6>A method for manufacturing a semiconductor package, which includes a step of arranging and sealing a semiconductor element and the colored layer of the release film for semiconductor encapsulation according to <3> or <4> opposite to each other in a mold.

Advantages of the Invention

[0010] According to one aspect of the present disclosure, it is possible to provide a marking film for semiconductor encapsulation that can suppress peeling of a laser-marked colored layer. Further, according to one aspect of the present disclosure, it is possible to provide a release film for semiconductor encapsulation that can suppress peeling of a laser-marked colored layer, a semiconductor package using this release film for semiconductor encapsulation, and a method for manufacturing a semiconductor package.

Modes for Carrying Out the Invention

[0011] Hereinafter, embodiments for implementing the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the components (including element steps, etc.) are not essential unless otherwise specified. 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 of 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 there are a plurality of substances corresponding to each component in the composition, the content rate or content of each component means the total content rate or content of the plurality of substances present in the composition, unless otherwise specified. In the present disclosure, the particles corresponding to each component may contain a plurality of types of particles. When there are a plurality of types of particles corresponding to each component in the composition, the particle diameter 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 or two or more layers may be detachable. In the present disclosure, "(meth)acrylic" means at least one of acrylic and methacrylic, and "(meth)acrylate" means at least one of acrylate and methacrylate.

[0012] In the present disclosure, the average thickness of a layer or film is defined as the value calculated as the arithmetic mean of the thicknesses measured 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 a plurality of layers are laminated or the total thickness of the plurality of layers, an electron microscope may be used to observe and measure the cross-section of the measurement target.

[0013] In the present disclosure, the "average particle diameter" is determined as the particle diameter (50%D) at which the cumulative volume from the small particle diameter side is 50% in the particle size distribution curve of volume cumulative by the laser diffraction scattering particle size distribution measurement method. For example, it can be measured using a particle size distribution measuring device that utilizes the laser light scattering method (for example, "SALD-3000" manufactured by Shimadzu Corporation).

[0014] <Semiconductor Encapsulation Marking Film> The semiconductor encapsulation marking film of the present disclosure (hereinafter, may be referred to as "marking film") includes two types of colored layers having different colors, and the second colored layer in contact with the encapsulating resin layer among the colored layers is a white layer having a near-infrared transmittance of 1064 nm of 0.22 or less. The portion (printed portion) removed by the laser marking method or the like of the colored layer can be recognized from the outside of the semiconductor as identification information.

[0015] The components constituting the colored layer included in the marking film of the present disclosure are not particularly limited as long as the colored layer in contact with the encapsulating resin layer among the colored layers is a white layer having a near-infrared transmittance of 1064 nm of 0.22 or less, and various materials used in the technical field can be combined to form the colored layer.

[0016] The coloring layer may, for example, contain a colorant, a thermosetting resin, and a curing agent. The coloring layer may also contain other components such as a curing accelerator, a thermoplastic resin, and an inorganic filler. When there are two or more coloring layers, the colorants contained in each coloring layer may be the same or different, and it is preferable that they are different. When the marking film has two coloring layers with different colors, the coloring layer in contact with the encapsulating resin layer among the coloring layers may be a white layer with a near-infrared transmittance of 0.22 or less at a wavelength of 1064 nm.

[0017] The average thickness of the coloring layer is preferably 3 μm to 100 μm, and more preferably 5 μm to 60 μm. When there are two or more coloring layers, it is preferable that the average thickness of the entire coloring layer is within the above range.

[0018] -Colorant- The coloring layer may contain a colorant. As the colorant, various organic pigments, inorganic pigments, etc. can be used. Examples of the colorant include black pigments, white pigments, yellow pigments, magenta pigments, cyan pigments, red pigments, blue pigments, green pigments, etc. Among these, from the viewpoint of the visibility of various information printed on the surface of the encapsulating resin, it is preferable to use black pigments and white pigments. Examples of the black pigment include carbon black such as acetylene black and ketjen black, titanium black, aniline black, etc. Examples of the white pigment include basic lead carbonate (2PbCO 3 ·Pb(OH) 2 ), zinc oxide (ZnO), titanium oxide (TiO 2 ), strontium titanate (SrTiO 3 ), etc.

[0019] The content rate of the colorant in the coloring layer can be appropriately set according to the type of the colorant. The content rate of the colorant in the coloring layer is preferably in the range of 0.5 mass% to 12.0 mass%, more preferably in the range of 1 mass% to 10 mass% from the viewpoint of visibility, for example, when a black pigment is used as the colorant. The content rate of the colorant in the coloring layer is preferably in the range of 15 mass% to 60 mass%, more preferably in the range of 20 mass% to 50 mass% from the viewpoint of visibility, for example, when a white pigment is used as the colorant. When the marking film includes two types of coloring layers having different colors, a combination of a coloring layer containing a white pigment and a coloring layer containing a black pigment is preferable. When a coloring layer containing a white pigment and a coloring layer containing a black pigment are laminated in this order on the surface of the semiconductor package, by irradiating the surface with laser light, the coloring layer containing the black pigment can be sublimated and removed. At this time, since the coloring layer containing the white pigment appears from the portion where the coloring layer containing the black pigment has been removed, printing with high contrast and good visibility becomes possible.

[0020] As the laser used in the laser marking method, there are mainly a carbon dioxide laser and a YAG laser. Since the laser used in the laser marking method is often a YAG laser, as the black pigment contained in the coloring layer, it is preferable to use carbon black that is easily volatilized by the YAG laser. In addition, a YVO4 laser can also be used as the laser used in the laser marking method.

[0021] -Thermosetting resin- The coloring layer may contain a thermosetting resin. Examples of the thermosetting resin include an epoxy resin, a triazine resin, a phenol resin, a melamine resin, a cyanate ester resin, and modified products of these resins. These resins may be used alone or in combination of two or more. From the viewpoint of heat resistance, the thermosetting resin is preferably at least one selected from the group consisting of an epoxy resin, a phenol resin, and a triazine resin, and more preferably an epoxy resin.

[0022] As the epoxy resin, bifunctional epoxy resins such as bisphenol A type epoxy resin, novolak type epoxy resins such as phenol novolak type epoxy resin and cresol novolak type epoxy resin can be used. In addition, generally known resins such as polyfunctional epoxy resins, glycidylamine type epoxy resins, heterocyclic ring-containing epoxy resins, and alicyclic epoxy resins can be used. These epoxy resins may be used alone or in combination of two or more.

[0023] From the viewpoint of elastic modulus, 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 still more preferably 100 g / eq to 200 g / eq. The epoxy equivalent of the epoxy resin can be measured by the perchloric acid titration method in accordance with JIS K7236:2009.

[0024] Examples of bisphenol A type epoxy resins include products with trade names such as jER807, 815, 825, 827, 828, 834, 1001, 1004, 1007, 1009 manufactured by Mitsubishi Chemical Corporation, DER-330, 301, 361 manufactured by Dow Chemical Company, and YD8125, YDF8170 manufactured by Nippon Steel & Sumikin Epoxy Co., Ltd.

[0025] Examples of phenol novolak type epoxy resins include products with trade names such as jER152, 154 manufactured by Mitsubishi Chemical Corporation, EPPN-201 manufactured by Nippon Kayaku Co., Ltd., and DEN-438 manufactured by Dow Chemical Company. Examples of o-cresol novolak type epoxy resins include products with trade names such as EOCN-102S, 103S, 104S, 1012, 1025, 1027 manufactured by Nippon Kayaku Co., Ltd., and YDCN701, 702, 703, 704 manufactured by Nippon Steel & Sumikin Epoxy Co., Ltd.

[0026] Examples of polyfunctional epoxy resins include those manufactured by Mitsubishi Chemical Corporation under the trade name Epon 1031S, etc., those manufactured by Huntsman under the trade name Araldite 0163, etc., and those manufactured by Nagase Kasei Co., Ltd. under the trade name Denacol EX-611, 614, 614B, 622, 512, 521, 421, 411, 321, etc. Examples of amine-type epoxy resins include those manufactured by Mitsubishi Chemical Corporation under the trade name jER604, etc., those manufactured by Nippon Steel Epoxy Co., Ltd. under the trade name YH-434, etc., those manufactured by Mitsubishi Gas Chemical Company, Inc. under the trade name TETRAD-X, TETRAD-C, etc., and those manufactured by Sumitomo Chemical Co., Ltd. under the trade name ELM-120, etc.

[0027] Examples of epoxy resins containing a heterocyclic ring include those manufactured by Huntsman under the trade name Araldite PT810, etc., those manufactured by UCC under the trade name ERL4234, 4299, 4221, 4206, etc., and those manufactured by Nissan Chemical Industries, Ltd. under the trade name TEPIC-PAS, etc.

[0028] Examples of alicyclic epoxy resins include those manufactured by Daicel Corporation under the trade name EHPE-3150, CEL2021P, CEL2000, etc.

[0029] When a resin having a non-aromatic cyclic structure is an epoxy resin, examples of the epoxy resin include epoxy resins containing a heterocyclic ring, alicyclic epoxy resins, etc. From the viewpoint of solubility in a solvent, alicyclic epoxy resins are more preferable.

[0030] From the viewpoint of elastic modulus, the content of the thermosetting resin in the colored layer is preferably in the range of 5% by mass to 50% by mass, more preferably in the range of 10% by mass to 50% by mass, and still more preferably in the range of 15% by mass to 50% by mass. When there are two or more colored layers, the content of the thermosetting resin in each colored layer is preferably within the above range.

[0031] -Curing agent- The coloring layer may contain a curing agent. As the curing agent, known curing agents generally used can be used. When the thermosetting resin is an epoxy resin, examples of the curing agent 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, phenolic resins such as phenol novolak resin, bisphenol A novolak resin, and cresol novolak resin. Among these, from the viewpoint of the curability of the epoxy resin, phenolic resins, acid anhydrides, amines, etc. are preferable.

[0032] Examples of the phenolic resin used as the curing agent include those manufactured by DIC Corporation, trade names: Phenolite LF-2882, Phenolite LF-2822, Phenolite TD-2090, Phenolite TD-2149, Phenolite VH-4150, Phenolite VH-4170, etc., and those manufactured by Mitsui Chemicals, Inc., trade names: XLC-LL, XLC-4L, etc. These may be used alone or in combination of two or more.

[0033] Examples of the acid anhydride used as the curing agent include phthalic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, 4-methyltetrahydrophthalic anhydride, 3-methylhexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, hymic anhydride, methyl hymic anhydride, chlorendic anhydride, succinic anhydride, trimellitic anhydride, pyromellitic anhydride, trialkyltetrahydrophthalic anhydride maleic acid adduct, benzophenone tetracarboxylic dianhydride, hydrogenated methyl nadic anhydride, dodecenyl succinic anhydride, etc. These may be used alone or in combination of two or more.

[0034] Examples of the amines used as the curing agent include linear aliphatic amines, cyclic aliphatic amines, aliphatic aromatic amines, aromatic amines, etc. As amines used as curing agents, specifically, there are aromatic amine curing agents having 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, 2,4-diaminoanisole; aromatic amine curing agents having two aromatic rings such as 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 4,4'-methylenebis(2-ethylaniline), 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, 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, polytetramethylene oxide diparaaminobenzoate; condensates of aromatic diamines and epichlorohydrin; reaction products of aromatic diamines and styrene, and the like.

[0035] From the viewpoint of suppressing each unreacted component to a small amount and allowing the curing reaction to proceed sufficiently, 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 set in the range of 0.7 to 1.3, and even more preferably set in the range of 0.8 to 1.2 as the blending ratio of the thermosetting resin and the curing agent. When there are two or more colored layers, it is preferable that the ratio (equivalent number of thermosetting resin / equivalent number of curing agent) in each colored layer is within the above range.

[0036] -Curing accelerator- The coloring layer may contain a curing accelerator. As the curing accelerator, it is preferable to use various imidazoles. Examples of imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and the like. Examples of commercially available imidazoles include those manufactured by Shikoku Kasei Kogyo Co., Ltd., trade names: 2E4MZ, 2PZ-CN, 2PZ-CNS, 2P4MHZ-PW, and the like. Also, an organic phosphine compound can be used as the curing accelerator. Specific examples of the organic phosphine compound 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 the coloring layer contains a curing accelerator, the content of the curing accelerator in the coloring layer is preferably in the range of 0.01% to 5.0% by mass, more preferably in the range of 0.05% to 4.0% by mass, and even more preferably in the range of 0.1% to 3.0% by mass from the viewpoint of the curing rate.

[0037] -Thermoplastic resin- The coloring layer may contain a thermoplastic resin. Examples of the thermoplastic resin include, but are not limited to, 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. The thermoplastic resin preferably does not have an aromatic ring. When the thermoplastic resin is contained in the coloring layer, the content of the thermoplastic resin in the coloring layer is preferably in the range of 1% by mass to 30% by mass, more preferably in the range of 5% by mass to 20% by mass, and still more preferably in the range of 5% by mass to 17% by mass.

[0038] The weight average molecular weight (Mw) of the thermoplastic resin is preferably in the range of 500,000 to 2,000,000, more preferably in the range of 600,000 to 1,700,000, and still more preferably in the range of 700,000 to 1,500,000. In the present disclosure, the weight average molecular weight is a value determined by using gel permeation chromatography, under the following apparatus and measurement conditions, and converting using a calibration curve of standard polystyrene. In preparing the calibration curve, 5 sample sets (PStQuick MP-H, PStQuick B [trade names, manufactured by Tosoh Corporation]) were used as standard polystyrenes. Apparatus: High-speed GPC apparatus HLC-8320GPC (detector: differential refractometer) [trade name, manufactured by Tosoh Corporation] Solvent used: Tetrahydrofuran (THF) Column: Column TSKGEL SuperMultipore HZ-H [trade name, manufactured by Tosoh Corporation] Column size: Column length 15 cm, column inner diameter 4.6 mm Measurement temperature: 40 °C Flow rate: 0.35 mL / min Sample concentration: 10 mg / 5 mL of THF Injection volume: 20 μL

[0039] -Inorganic filler- The coloring layer may contain an inorganic filler. Examples of the inorganic filler include crystalline silica, amorphous silica, aluminum oxide, calcium carbonate, magnesium carbonate, aluminum nitride, boron nitride, etc. These inorganic fillers may be used alone or in combination of two or more. Among them, silica fillers such as crystalline silica and amorphous silica are preferable from the viewpoint of versatility. Examples of the silica filler include those manufactured by Nippon Aerosil Co., Ltd., trade names: R972, R972V, R972CF, etc., those manufactured by Admatechs Co., Ltd., trade names: SO-E1, SO-E2, SO-E5, SO-C1, SO-C2, SO-C3, SO-C5, etc., those manufactured by Ryushin Co., Ltd., trade names: PLV-6, PLV-4, TFC-12, TFC-24, USV-5, USV-10, etc. From the viewpoint of film-forming property, the average particle diameter (50%D) of the inorganic filler is preferably in the range of 0.01 μm to 20.0 μm, more preferably in the range of 0.1 μm to 10.0 μm, and still more preferably in the range of 0.2 μm to 1.0 μm. When the coloring layer contains an inorganic filler, the content of the inorganic filler in the coloring layer is preferably in the range of 0.5 mass% to 70.0 mass%, more preferably in the range of 1 mass% to 60 mass%, and still more preferably in the range of 5 mass% to 55 mass% from the viewpoint of elastic modulus.

[0040] The coloring layer provided in the marking film may be provided on the base material. As the base material used for the marking film, the same base material as that used for the release film for semiconductor encapsulation described later can be used.

[0041] (Manufacturing method of marking film for semiconductor encapsulation) The marking film can be manufactured by a known method. For example, the marking film can be manufactured by applying a composition for forming a coloring layer containing components constituting the coloring layer on one side of a substrate and drying it. The details of the composition for forming the coloring layer and the details when applying the composition for forming the coloring layer to the substrate are the same as those in the case of the manufacturing method of the release film for semiconductor encapsulation.

[0042] <Release Film for Semiconductor Encapsulation> The release film for semiconductor encapsulation of the present disclosure (hereinafter, may be referred to as a "release film") has a substrate, a release layer, and the marking film for semiconductor encapsulation in this order. The portion (printed portion) removed by a laser marking method or the like of the coloring layer contained in the marking film for semiconductor encapsulation is recognized as identification information.

[0043] In the release film of the present disclosure, discoloration of the printed portion is suppressed. The reason is not clear, but it is presumed as follows. A semiconductor package is manufactured by encapsulating a semiconductor element with a sealing material in a state where the semiconductor element and the coloring layer in the release film for semiconductor encapsulation are opposed to each other and arranged in a mold. When encapsulating the semiconductor element with the sealing material, a pressure treatment is performed under predetermined temperature conditions. After the pressure treatment, the coloring layer is laminated on the surface of the sealing resin layer that encapsulates the semiconductor element (that is, the surface of the semiconductor package). The resin contained in the coloring layer is less likely to be oxidized by heat during the laser marking method and the accompanying yellowing. Therefore, it is presumed that when a printed portion is formed on the coloring layer on the surface of the semiconductor package by the laser marking method, discoloration of the printed portion is likely to be suppressed. In this regard, it is preferable that the coloring layer contains a resin having a non-aromatic cyclic structure.

[0044] The release film of the present disclosure has a substrate, a release layer, and a coloring layer, and may have other layers as necessary. Hereinafter, various materials constituting the release film for semiconductor encapsulation of the present disclosure will be described.

[0045] (Substrate) The release film includes a base material. The material of the base material is not particularly limited and can be appropriately selected from resin-containing base materials used in the relevant technical field. From the perspective of improving the followability to the shape of the mold, it is preferable to use a resin-containing base material with excellent stretchability. Considering that the encapsulation of the semiconductor element with the encapsulant is performed at a high temperature (about 100°C to 200°C), it is desirable that the base material has heat resistance at this temperature or higher. Also, when arranging the release film on the mold and when the resin during molding flows, in order to suppress the occurrence of wrinkles in the encapsulating resin, breakage of the release film, etc., it is desirable to select the material of the base material in consideration of the elastic modulus, elongation, etc. at high temperatures.

[0046] From the perspectives of heat resistance and elastic modulus at high temperatures, the base material preferably contains a polyester resin. Examples of the polyester resin include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, and copolymers and modified resins thereof. Among them, those obtained by molding the polyester resin into a sheet shape are preferable, more preferably a polyester film, and even more preferably a biaxially stretched polyester film from the perspective of followability to the mold, and particularly preferably a biaxially stretched polyethylene terephthalate film. The average thickness of the base material is not particularly limited, preferably in the range of 5 μm to 100 μm, and more preferably in the range of 10 μm to 70 μm. When the average thickness of the base material is 5 μm or more, the handleability is excellent and wrinkles are less likely to occur. When the average thickness of the base material is 100 μm or less, the followability to the mold during molding is excellent, so the occurrence of wrinkles in the molded semiconductor package is likely to be suppressed. Incidentally, the average thickness is measured by the micrometer method in accordance with general JIS 2151.

[0047] (Release layer) The release film includes a release layer. The components constituting the release layer are not particularly limited, and various materials used in the relevant technical field can be combined and used. The release layer may contain, for example, resin particles and a binder, and may contain other components as necessary.

[0048] - Resin particles - The type of resin constituting the resin particles is not particularly limited. The resin particles preferably contain at least one selected from the group consisting of acrylic resins, polyolefin resins, polystyrene resins, polyacrylonitrile resins, and silicone resins. From the viewpoint of releasability with respect to the semiconductor package, it is more preferable that the resin particles contain at least one selected from acrylic resins, polystyrene resins, and polyacrylonitrile resins. From the viewpoint of the uniformity of the surface appearance of the semiconductor package, the resin particles preferably have the property of being insoluble or hardly soluble in an organic solvent (for example, toluene, methyl ethyl ketone, and ethyl acetate) that can be used in the preparation of the composition for forming the release layer. Here, the property of being insoluble or hardly soluble in an organic solvent means that the gel fraction is 97% or more after dispersing the resin particles in an organic solvent such as toluene and holding at 50°C for 24 hours in a gel fraction test conforming to JIS K6769:2013.

[0049] The average particle diameter (50%D) of the resin particles is preferably in the range of 1 μm to 55 μm. When the average particle diameter of the resin particles is 1 μm or more, it is possible to sufficiently form irregularities on the surface of the release layer, and the uniformity of the surface appearance of the molded semiconductor package is improved and the flow marks of the encapsulant tend to be suppressed. Also, when the average particle diameter of the resin particles is 55 μm or less, it is not necessary to excessively increase the average thickness of the release layer to fix the resin particles in the release layer, which is preferable from the viewpoint of cost. The upper limit value of the average particle diameter of the resin particles is preferably 55 μm, more preferably 50 μm, from the viewpoint of the surface appearance of the semiconductor package. The lower limit value of the average particle diameter of the resin particles is more preferably 2 μm, even more preferably 3 μm, from the viewpoint of cost.

[0050] The shape of the resin particles contained in the release layer is not particularly limited and may be any of spherical, elliptical, amorphous, etc.

[0051] The content ratio of the resin particles contained in the release layer is preferably in the range of 5% to 65% by volume. When the content ratio is 5% by volume or more, it is possible to sufficiently form irregularities on the surface of the release layer, improving the uniformity of the surface appearance of the molded semiconductor package and tending to sufficiently obtain the effect of suppressing the flow marks of the sealing material. From this perspective, the lower limit value of the content ratio of the resin particles is preferably 10% by volume, and more preferably 20% by volume. In addition, when the content ratio is 65% by volume or less, the resin particles are more likely to be fixed by the binder in the release layer described later, the possibility of the resin particles falling off is reduced, the falling off onto the surface of the molded semiconductor package can be suppressed, and it is also preferably economical. From this perspective, the upper limit value of the content ratio of the resin particles is preferably 60% by volume, and more preferably 50% by volume.

[0052] -Binder- The type of the binder that may be contained in the release layer is not particularly limited. When the release layer contains a binder, the resin particles are fixed in the release layer. From the perspectives of releasability from the semiconductor package, heat resistance, etc., the binder is preferably an acrylic resin or a silicone resin, and more preferably a crosslinked acrylic resin (hereinafter, also referred to as "crosslinked acrylic copolymer").

[0053] The acrylic resin may be an acrylic copolymer obtained by copolymerizing a low glass transition temperature (Tg) monomer such as butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, etc. as the main monomer and, if necessary, a functional group monomer such as acrylic acid, methacrylic acid, hydroxyethyl methacrylate, hydroxyethyl acrylate, acrylamide, acrylonitrile, etc. Also, the crosslinked acrylic copolymer can be produced by crosslinking the above acrylic resin. Examples of the crosslinking agent used in the production of the crosslinked acrylic copolymer include known crosslinking agents such as isocyanate compounds, melamine compounds, and epoxy compounds. Further, in order to form a gently spreading network structure in the acrylic resin, the crosslinking agent is more preferably a polyfunctional crosslinking agent having three or four functional groups or the like.

[0054] Since the crosslinked acrylic copolymer produced using the above crosslinking agent has a gently spreading network structure, when this crosslinked acrylic polymer is used as a binder for the release layer, the stretchability of the release layer is improved, and the inhibition of the stretchability of the base material is suppressed. Therefore, the followability of the release film to the mold during compression molding can be improved. From this viewpoint, the amount of the crosslinking agent used in the production of the crosslinked acrylic copolymer is preferably in the range of 3 parts by mass to 100 parts by mass, and more preferably in the range of 5 parts by mass to 70 parts by mass with respect to 100 parts by mass of the acrylic copolymer. When the amount of the crosslinking agent is 3 parts by mass or more, the strength of the binder is ensured, and thus the tendency to prevent the resin particles from falling off can be achieved. When the amount of the crosslinking agent is 100 parts by mass or less, the flexibility of the crosslinked acrylic copolymer is improved, and the stretchability of the release layer tends to be improved.

[0055] -Other components- The release layer may further contain a solvent, an anchoring improver, a crosslinking accelerator, an antistatic agent, a colorant, etc., if necessary.

[0056] -Average thickness of the release layer- The average thickness of the release layer is not particularly limited and is appropriately set in consideration of the relationship with the average particle diameter (50%D) of the resin particles used. The average thickness of the release layer is preferably in the range of 0.1 μm to 100 μm, and more preferably in the range of 1 μm to 50 μm. If the average thickness of the release layer is not extremely thinner than the average particle diameter of the resin particles to be used, it is difficult for the resin particles to become fixed in the release layer, and the resin particles are unlikely to fall off. Therefore, contamination of the surface of the molded semiconductor package by the resin particles is less likely to occur. Also, if the average thickness of the release layer is not extremely thicker than the average particle diameter of the resin particles to be used, effects such as improving the uniformity of the appearance of the surface of the molded semiconductor package and suppressing the flow marks of the encapsulant are likely to be obtained. Also, there is a tendency that it is less likely to result in economic disadvantages. Note that the average thickness of the release layer in the present disclosure means the average thickness in the dry state, and the release layer of the release film can be measured by the above-described method for measuring the average thickness of the layer.

[0057] (Coloring layer) The release film has one or two or more coloring layers. Details of the components constituting the coloring layer are the same as in the case of the above-described marking film. The release film may include two types of coloring layers having different colors on the release layer. In this case, it is preferable that the coloring layer that contacts the encapsulant resin layer after molding among the coloring layers is a white coloring layer having a near-infrared transmittance of 0.22 or less at a wavelength of 1064 nm. It is preferable to arrange the base material, the release layer, the coloring layer containing a black pigment, and the coloring layer containing a white pigment in this order in the release film for semiconductor encapsulation of the present disclosure. When a semiconductor package is molded using the release film for semiconductor encapsulation having such a configuration, the coloring layer containing the white pigment and the coloring layer containing the black pigment are laminated in this order on the surface of the semiconductor package. By irradiating the surface of the semiconductor package on which the coloring layer is laminated with laser light, the coloring layer containing the black pigment can be sublimated and removed. At this time, since the coloring layer containing the white pigment appears from the portion where the coloring layer containing the black pigment has been removed, printing with high contrast and good visibility becomes possible.

[0058] (Other configurations) The base material is the layer that contacts the mold surface, and depending on the material used, a larger peeling force may be required to peel the release film from the mold. When using a material that is difficult to peel from the mold for the base material, it is preferable to perform a treatment or the like to make it easier to peel. For example, the surface of the base material on the side opposite to the surface where the release layer is provided, that is, the surface of the base material on the mold side, is subjected to surface treatment such as embossing to improve the releasability from the mold, or a new separate release layer (second release layer) may be provided. The material of the second release layer is not particularly limited as long as it satisfies heat resistance, releasability 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, and it is preferably in the range of 0.1 μm to 100 μm.

[0059] Furthermore, if necessary, an anchoring improvement layer (primer layer), an antistatic layer, etc. may be provided between the release layer and the base material, between the base material and the second release layer, etc.

[0060] A protective film may be provided on the coloring layer of the release film for semiconductor encapsulation. Examples of the protective film include plastic films such as polytetrafluoroethylene film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, and polyimide film.

[0061] (Manufacturing method of release film for semiconductor encapsulation) The release film for semiconductor encapsulation can be manufactured by a known method. For example, a composition for forming a release layer containing components constituting the release layer is applied to one side of the base material and dried to form a release layer on the base material, and then a composition for forming a coloring layer containing components constituting the coloring layer is applied on the release layer and dried to form a coloring layer on the release layer, whereby the release film for semiconductor encapsulation may be manufactured. As another method, a release layer is formed on one substrate by applying a release layer-forming composition containing components constituting the release layer to one side of the substrate and drying it. On the other hand, a colored layer is formed on the other substrate by applying a colored layer-forming composition containing components constituting the colored layer to one side of the other substrate and drying it. Then, the release layer on one substrate and the colored layer on the other substrate may be bonded together to produce a release film for semiconductor encapsulation. The solvent used for adjusting the viscosity of the release layer-forming composition or the colored layer-forming composition is not particularly limited, and it is preferably an organic solvent capable of dispersing or dissolving each component constituting the release layer or the colored layer. Examples of the organic solvent include toluene, methyl ethyl ketone, ethyl acetate, and the like. As the other substrate, it may be a film that can serve as a protective film provided on the colored layer as necessary, and examples thereof include plastic films such as polytetrafluoroethylene film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, and polyimide film. Further, a treatment for improving the releasability may be performed on the surface of the other substrate as necessary.

[0062] The method of applying the release layer-forming composition or the colored layer-forming composition is not particularly limited, and known methods such as a roll coating method, a bar coating method, a kiss coating method, and a comma coating method can be used. The method of drying the applied release layer-forming composition or colored layer-forming composition is not particularly limited, and a known drying method can be used. For example, a method of drying at 50°C to 150°C for 0.1 minute to 60 minutes may be used.

[0063] <Semiconductor Package and Method for Manufacturing the Same> The semiconductor package of the present disclosure includes a semiconductor element, a sealing resin layer that seals the semiconductor element, and a colored layer on the surface of the sealing resin layer, and the colored layer is derived from the colored layer provided on the release film for semiconductor encapsulation of the present disclosure.

[0064] The semiconductor package of the present disclosure may be manufactured by any method. The semiconductor package of the present disclosure may be manufactured, for example, through a process of disposing a semiconductor element and a coloring layer in a semiconductor encapsulation release film of the present disclosure opposite to each other in a mold and encapsulating the semiconductor element. After the process of encapsulating the semiconductor element, laser marking may be performed on the coloring layer. In the process of encapsulating the semiconductor element, the semiconductor element may be encapsulated by compression molding or transfer molding. From the viewpoint of being able to encapsulate a wide area at once, compression molding is preferable.

[0065] Generally, in the compression molding of a semiconductor package, a semiconductor encapsulation release film is disposed in a mold of a compression molding apparatus, and the semiconductor encapsulation release film is made to follow the shape of the mold by vacuum suction or the like. Thereafter, a sealing material (for example, an epoxy resin or the like) of the semiconductor package is put into the mold, the semiconductor element is disposed thereon, and the sealing material is cured by compressing the mold while heating to mold the semiconductor package. Thereafter, the mold is opened and the molded semiconductor package is taken out. In this way, the semiconductor package can be manufactured. At this time, the coloring layer of the semiconductor encapsulation release film is laminated on the surface of the sealing resin layer of the semiconductor package. The thermosetting resin contained in the coloring layer is preferably an epoxy resin. Since the sealing material of the semiconductor package often contains an epoxy resin, when the coloring layer contains an epoxy resin as the thermosetting resin, the adhesion between the sealing resin layer and the coloring layer is likely to be improved. Therefore, it is easy to suppress the occurrence of wrinkles or the like in the coloring layer, and the appearance of the semiconductor package surface can be made more excellent.

Example

[0066] Hereinafter, the present disclosure will be described based on examples, but the present disclosure is not limited to the following examples. In the following examples, parts and % indicate parts by mass and mass % unless otherwise specified.

[0067] [Example 1] (Preparation of Release Film) 65 parts of an acrylic resin (monomer components: ethyl acrylate, butyl acrylate, and acrylonitrile), 35 parts of a tin catalyst (dinormal octyltin dilaurate), and a mixed solvent of isooctane and toluene (isooctane / toluene: 1 / 9 (mass basis)) were mixed to prepare a solution for the primer layer. Next, 100 parts of an acrylic resin (monomer component: alkyl acrylate), 17 parts of polyisocyanate as a crosslinking agent, 10 parts each of fillers (acrylic resin particles with an average particle diameter of 10 μm, acrylic resin particles with an average particle diameter of 3 μm, polyacrylonitrile resin particles with an average particle diameter of 7 μm), and a mixed solvent of toluene and methyl ethyl ketone (MEK) (toluene / MEK: 1 / 4 (mass basis)) were mixed to prepare a solution for the release layer. As a substrate, on one side of a biaxially stretched polyethylene terephthalate film with an average thickness of 25 μm, using a roll coater, the solution for the primer layer was applied, and then the solution for the release layer was overlaid and applied and dried so that the average thickness after drying was 10 μm to form a release layer, and a release film was obtained. The drying temperature was 100 °C and the drying time was 2 minutes.

[0068] (Preparation of First Coloring Layer) 6.1 parts of a thermoplastic resin (acrylate-based polymer, monomer components: butyl acrylate and acrylonitrile, weight average molecular weight 9,000,000), 22.1 parts of a thermosetting resin (epoxy equivalent: 138 g / eq), 18.9 parts of a curing agent (hexahydrophthalic anhydride), 8.6 parts of a black pigment (carbon black, average particle diameter (50%D): 0.5 μm), 1.9 parts of a curing accelerator (2-ethyl-4-methylimidazole), 41.1 parts of a silica filler (average particle diameter (50%D): 0.5 μm), and methyl ethyl ketone were mixed to prepare a solution of a composition for forming the first coloring layer with a solid content concentration of 35.0 mass%.

[0069] The solution of the composition for forming the first colored layer was applied onto a polyethylene terephthalate film with an average thickness of 38 μm using a comma coater, and then dried at 85°C for 2 minutes to produce a black first colored resin film with an average thickness of 10 μm.

[0070] (Production of the second colored layer) A thermoplastic resin (acrylate polymer, monomer components: butyl acrylate and acrylonitrile, weight average molecular weight 9 million), a thermosetting resin (epoxy equivalent: 138 g / eq), a curing agent (hexahydrophthalic anhydride), a white pigment A (spherical titanium oxide, average particle diameter (50%D): 0.25 μm, surface treatment: alumina, silica, siloxane), a curing accelerator (2-ethyl-4-methylimidazole), a silica filler (average particle diameter (50%D): 0.5 μm), and methyl ethyl ketone were mixed to prepare a solution of the composition for forming the second colored layer with a solid content concentration of 38.0% by mass. The composition ratio based on the mass of the composition is shown in Table 1. The unit is "parts by mass".

[0071] The solution of the composition for forming the second colored layer was applied onto a polyethylene terephthalate film with an average thickness of 38 μm using a comma coater, and then dried at 85°C for 2 minutes to produce a white second colored resin film with an average thickness of 10 μm.

[0072] The above-mentioned first colored resin film and the second colored resin film were laminated using a roll laminator at 80°C and 0.4 MPa in a state where the black first colored layer and the white second colored layer were in contact with each other to produce a marking film in which the black colored layer and the white colored layer were laminated.

[0073] [Production of the release film integrated with the colored layer] The above-mentioned release film and the marking film were laminated using a roll laminator at 80°C and 0.4 MPa in a state where the release film and the black first colored layer were in contact with each other to produce a release film integrated with the colored layer.

[0074] (Compression molding process) The colored layer integrated release film was attached to the upper mold of a compression molding die in which a semiconductor bare chip was set in the lower mold, and the semiconductor bare chip and the colored layer of the colored layer integrated release film were arranged opposite to each other. After fixing the colored layer integrated release film to the upper mold of the compression molding die under vacuum, the mold was clamped, and a sealing material was molded (compression molded) to obtain a semiconductor package. The mold temperature was 165 °C, the molding pressure was 6.86 MPa (70 kgf / cm 2 ), and the molding time was 180 seconds.

[0075] (Curing) Next, the semiconductor package was thermally cured. The curing temperature was 175 °C, under atmospheric pressure, and the curing time was 300 minutes.

[0076] (Laser Marking) The semiconductor package was printed under the following conditions. The conditions for laser marking are as follows. Laser marking device: Trade name "MD-H9800", manufactured by Keyence Corporation Wavelength: 1064 nm Output (intensity): 2 W, 8 W Scan speed: 700 mm / s Q-switch frequency: 50 kHz Marking shape: Rectangle (15 mm × 15 mm)

[0077] [Examples 2 to 4 and Comparative Examples] The first colored resin film was the same as in Example 1, and white pigment B (rod-shaped titanium oxide, average particle diameter (50%D): 0.3 - 0.5 μm, surface treatment: alumina), white pigment C (spherical titanium oxide, average particle diameter (50%D): 1.0 μm, surface treatment: alumina), and white pigment D (spherical titanium oxide, average particle diameter (50%D): 0.25 μm, surface treatment: alumina, silica, polyol) were used. A colored layer integrated release film was produced using the second colored resin film with the composition ratios shown in Table 1. A semiconductor package was produced and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0078] [Table 1]

[0079] (Evaluation method) -Transmittance- The transmittance of the second colored layer (white colored layer) was measured using a spectrophotometer U2900 (manufactured by Hitachi High-Technologies Corporation, trade name), the transmittance at 1064 nm was read, and shown in Table 2.

[0080] -Appearance- The appearance of the second colored layer exposed by laser marking was visually evaluated. A: No defect in the colored layer B: Partial defect in the colored layer C: Disappearance of the colored layer

[0081] -Checkerboard test- The adhesion between the encapsulant and the second colored layer was evaluated according to the checkerboard test defined in JIS K5400 for the rectangular portion formed by laser marking. Evaluation was made based on the number of squares remaining without peeling. A: 90 or more B: 50 or more and less than 90 C: Less than 50 The results are shown in Table 2.

[0082]

Table 2

[0083] It can be seen from Table 2 that the release film for semiconductor encapsulation of the present disclosure having a white colored layer with a light transmittance of 0.22 or less at a wavelength of 1064 nm suppresses peeling of the colored layer by laser marking and imparts excellent adhesion to the semiconductor package. This is presumably because it is difficult for the laser light to penetrate the colored layer, so the encapsulant located below the colored layer is hardly affected by the laser light, and a decrease in the adhesiveness with the colored layer is suppressed.

Claims

1. A semiconductor encapsulation marking film comprising two kinds of colored layers with different colors from each other, wherein one of the colored layers is laminated on the surface of a semiconductor encapsulant layer and is a white colored layer with a light transmittance of 1064 nm of 0.22 or less.

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

3. A release film for semiconductor encapsulation, in which a base material, a release layer, and the semiconductor encapsulation marking film according to claim 1 are laminated in this order.

4. A release film for semiconductor encapsulation, in which a base material, a release layer, and the semiconductor encapsulation marking film according to claim 2 are laminated in this order.

5. A semiconductor package having 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 the colored layer of the release film for semiconductor encapsulation according to claim 3 or 4.

6. A method for manufacturing a semiconductor package, which comprises a step of disposing a semiconductor element and the colored layer of the release film for semiconductor encapsulation according to claim 3 or 4 opposite to each other in a mold and sealing them.

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