TW201819141A - Releasing film - Google Patents

Abstract

A releasing film, comprising a substrate and a releasing layer that is positioned on the substrate and includes a resin component and a filler, the releasing film satisfying a ratio of a volume average particle size of the filler A ([mu]m) and a mass per 1 m2 of the releasing layer B (g/m2) (A/B) of 1 or less.

Description

Release film

This invention relates to a release film.

The semiconductor wafer is usually sealed with a resin in order to block external air and protect it, and is mounted on the substrate in a state called a packaged molded article. This molded article is usually formed in the form of a packaged molded article of each wafer which is connected via a runner which is a flow path of a sealing resin. In this case, the mold release property of the molded article from the mold is obtained by the structure of the mold used for molding the molded article, the release agent or the like to the sealing resin.

On the other hand, due to the miniaturization and multi-needle requirements of the package, Ball Grid Array (BGA), Quad Flat Non-leaded (QFN), wafer level wafer size The demand for packages such as the Wafer Level-Chip Size Package (WL-CSP) method has increased. In the QFN method, in order to ensure the pitch and prevent the generation of the burrs of the terminal portion by the sealing material, in the BGA method and the WL-CSP method, in order to improve the mold release property of the package from the mold, the resin is used for mold release. Film (for example, refer to Patent Document 1). A molding method using such a release film is referred to as "film-assisted molding".

In the field of the BGA method and the WL-CSP system, the molding method is changing from the previous transfer molding method to the compression molding method for the purpose of increasing the size and efficiency of one shot.

Further, there has been proposed a process in which a functional sheet having a different function is mounted on a release film in advance, and a functional sheet is placed on a semiconductor package in a molding step, regardless of the molding methods. (For example, refer to Patent Document 2 and Patent Document 3). [Prior Art Document] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. JP-A-2007-158937 (Patent Document No. 2007-287937) [Patent Document 3] WO2013/183671

[Problems to be Solved by the Invention] In the methods described in Patent Document 2 and Patent Document 3, in the step of molding a semiconductor package, the functional sheet can be disposed on the semiconductor package. On the other hand, in the actual step, it is desirable that the release film satisfies the performance that the functional sheet is not released from the release layer in the step up to the molding step, and the functional sheet is in the molding step. The performance of demolding is performed well.

In the release film which is widely used by the compression molding method, the performance of retaining the functional sheet cannot be imparted. Therefore, in order to mold the functional sheet on the semiconductor package in the molding step using the release film, it is necessary to dispose the release film in the mold and then provide the functional sheet. However, the step of disposing the functional sheet on the release film disposed in the complicated shape and in the heated mold is difficult to automate, and there is a problem that work efficiency and safety are lacking in manual work.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a release film which is excellent in performance of a functional sheet and a performance of releasing a functional sheet in a molding step until a molding step. . [Means for solving the problem]

The following embodiments are included in the means for solving the above problems. <1> A release film comprising: a substrate; and a release layer provided on the substrate and comprising a resin component and a filler; a volume average particle diameter A (μm) of the filler and the release The ratio (A/B) of the mass B (g/m ² ) per 1 m ² of the mold layer is 1 or less. <2> The release film according to <1>, wherein the filler has a volume average particle diameter A of from 1 μm to 50 μm. <3> The release film according to <1>, wherein the release layer has a mass B per 1 m ² of from 0.1 g/m ² to 100 g/m ² . The release film according to any one of <1> to <3> wherein the resin component contains a thermosetting resin. The release film according to any one of <1> to <4> which further contains a crosslinking agent, and the content of the crosslinking agent is 1 part by mass based on 100 parts by mass of the resin component. ~10 parts by mass. The release film according to any one of <1> to <5> wherein the substrate contains a material selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polynaphthalene. At least one of the group consisting of ethylene diformate. [Effects of the Invention]

According to the present invention, it is possible to provide a release film which retains the performance of the functional sheet up to the molding step and which is excellent in the performance of releasing the functional sheet in the molding step.

Hereinafter, embodiments for carrying out the invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, constituent elements (including element steps, etc.) are not necessarily required unless otherwise specified. Numerical values and ranges thereof are also the same and do not limit the invention.

In the present specification, the term "step" is used in addition to the steps independent of the other steps, and even if it is not clearly distinguishable from other steps, the step is included as long as the purpose of the step is achieved. In the present specification, the numerical range indicated by "~" includes the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the numerical ranges described in the above paragraphs, the upper limit or the lower limit described in one numerical range may be replaced with the upper or lower limit of the numerical range described in the other stages. Further, in the numerical ranges described in the present specification, the upper limit or lower limit of the numerical range may be replaced with the value shown in the examples. In the present specification, the content or content of each component in the composition is such that when a plurality of substances corresponding to the respective components are present in the composition, unless otherwise specified, the plurality of substances present in the composition are used. The total content or content of the product. In the present specification, when the particle diameter of each component in the composition is a plurality of particles corresponding to the respective components in the composition, unless otherwise specified, it means a mixture of the plurality of particles present in the composition. Value. In the term "layer" or "film" as used in the specification, when the region in which the layer or the film is present is observed, in addition to the case where the entire region is formed, only a part of the region is formed. Happening. In the present specification, the term "layered" means that layers are accumulated, and two or more layers may be combined, and two or more layers may be attached or detached. In the present specification, "(meth)acryloyl group" means at least one of an acryloyl group and a methacrylic group, and "(meth)acrylic acid" means at least one of acrylic acid and methacrylic acid, "(A) By acrylate is meant at least one of acrylate and methacrylate.

<Release film> The release film of this embodiment has a base material, and a release layer provided on the base material and containing a resin component and a filler, and the volume average particle diameter A (μm) of the filler The ratio (A/B) of the mass B (g/m ² ) per 1 m ² of the release layer is 1 or less.

In the release film of the present embodiment, the performance of the functional sheet is maintained until the molding step, and the performance of releasing the functional sheet during the molding step is excellent. Therefore, it can be suitably used for a method of arranging a functional sheet on the surface of a semiconductor package, for example, in a molding step of a semiconductor package.

The reason for maintaining the performance of the functional sheet and the performance of releasing the functional sheet during the molding step in the molding step of the release film of the present embodiment is not necessarily clear, but it is presumed to be released by the mold release. The appropriate adhesiveness imparted by the resin component contained in the layer and the appropriate surface unevenness imparted by the filler contained in the release layer are caused.

The volume average particle diameter A (μm) of the filler contained in the release layer is compared with the mass B (g/m ² ) per 1 m ² of the release layer from the viewpoint of maintaining the performance of the functional sheet. Preferably, it is 1.0 or less, more preferably 0.7 or less, and further preferably 0.5 or less.

The lower limit of A/B is not particularly limited. For example, depending on the type and application of the semiconductor package, when the pressure at the time of molding is to be increased, or when the finish of the semiconductor package is to be roughened, a high mold release is applied to the release film. The value of A/B is preferably larger from the viewpoint of performance or roughening of the roughness of the surface. For example, it is preferably 0.3 or more, more preferably 0.5 or more.

[Release Layer] The release layer contains a resin component and a filler, and a ratio of a volume average particle diameter A (μm) of the filler to a mass B (g/m ² ) per 1 m ² of the release layer (A) /B) is 1 or less.

In the present embodiment, the volume average particle diameter A (μm) of the filler is a value measured by a light diffraction/scattering method, and the particle diameter when the volume-based particle size distribution is 50% from the small-diameter side is set to (D50).

The range of the mass B (g/m ² ) per 1 m ² of the release layer is not particularly limited, and may be selected in consideration of the relationship with the average particle diameter of the filler. For example, it is preferably from 0.1 g/m ² to 100 g/m ² , more preferably from 1 g/m ² to 50 g/m ² . When the mass B per 1 m ² of the release layer is 0.1 g/m ² or more, a sufficient amount of the resin component is contained in the release layer, and the desired flexibility and elongation are sufficiently obtained in the molding step, and the suppression is performed. The tendency to peel off or fall off from the release layer of the substrate. Further, the flexibility is sufficiently obtained, and the ability to maintain the functional sheet is favorably maintained. When the mass B per 1 m ² of the release layer is 100 g/m ² or less, the release layer is prevented from becoming too thick, and the flatness of the release film is impaired due to heat shrinkage stress during thermal curing. The tendency of the phenomenon. In addition, there is a tendency that the release sheet is prevented from being too soft and the functional sheet to be mounted is buried in the release layer, so that it cannot be accurately placed on the surface of the package.

In the present embodiment, the method of determining the mass B (g/m ² ) per 1 m ² of the release layer is not particularly limited. For example, the mass (g) of the release film cut out in such a manner that the area is 100 cm ² (for example, a size of 10 cm × 10 cm), and the release layer after removing the release layer from the release film using an organic solvent or the like The mass (g) of the release layer is determined by the mass (g) of the substrate, and the obtained value is multiplied by 100 to obtain the mass (g) of the release layer per 1 m ² , thereby obtaining The mass B (g/m ² ) per 1 m ² of the release layer.

The thickness of the release layer is not particularly limited. For example, it is preferably from 0.1 μm to 100 μm. When the thickness of the mold release layer is 0.1 μm or more, the resin component can sufficiently retain the filler. Therefore, it is less likely to cause the filler to fall off during molding and to be mixed into the package, and the semiconductor package tends to be stably produced. When the thickness of the release layer is 100 μm or less, the raw material for the release layer can be saved, and it is preferable from the viewpoint of production cost.

In the present embodiment, the thickness of the release layer is an average value of the values obtained by measuring five points at an arbitrary position. The thickness of the release layer can be measured, for example, using a general-purpose micrometer.

The release layer may have irregularities on the outer surface (the surface opposite to the surface on the substrate side) depending on the application. When the release layer has irregularities on the outer surface, the arithmetic mean roughness (Ra) of the outer surface of the release layer (the surface opposite to the surface on the substrate side) from the viewpoint of the uniformity of the appearance of the package surface It is preferably 0.5 μm to 5 μm. Further, the ten-point average roughness (Rz) of the outer surface is preferably from 5 μm to 50 μm.

In the present embodiment, the arithmetic mean roughness (Ra) and the ten-point average roughness (Rz) of the outer surface of the release layer may be, for example, a surface roughness measuring device (for example, a small flaw research institute, model SE-). 3500) Results obtained by measuring the tip end diameter of the stylus: 2 μm, the conveying speed: 0.5 mm/s, and the scanning distance: 8 mm, and by Japanese Industrial Standards (JIS) B0601 (2013) A value obtained by analysis by a method specified in International Organization for Standardization (ISO) 4287 (1997).

The adhesive force at 25 ° C of the outer surface of the release layer is preferably 1.0 gf or more. When the adhesive force at 25 ° C of the outer surface is 1.0 gf or more, the performance of the functional sheet is maintained to be excellent even after the molding step.

The adhesive force at 170 ° C of the outer surface of the release layer is preferably 20.0 gf or less. When the adhesive force at 170 ° C of the outer surface is 20.0 gf or less, the performance of demolding the functional sheet in the molding step tends to be more excellent.

The adhesive force (gf) of the outer surface of the release layer in the present embodiment can be, for example, a viscosity tester (for example, manufactured by Rhesca) and a probe having a diameter of 5 mm to measure the front load to be 10 Gf, a value obtained by measuring the pre-measurement load time of 1 second and the measurement of the ascending speed of 600 mm/min.

The content of the filler in the release layer is not particularly limited. For example, it is preferably 1.0% by mass to 50.0% by mass based on the total mass of the release layer. When the content of the filler is 1.0% by mass or more based on the total mass of the release layer, the surface of the molded semiconductor package can be finished to have a non-uniform and uniform appearance by the surface roughness of the release layer. tendency. When the content of the filler is 50.0% by mass or less based on the total mass of the release layer, the resin component can sufficiently retain the filler component. Therefore, the filler component is less likely to be detached during molding and mixed into the package, and the resin component can be stably stabilized. The tendency to produce semiconductor packages.

The release layer may contain, in addition to the resin component and the filler, other components such as a solvent, an anchoring enhancer, a crosslinking accelerator, an antistatic agent, and a colorant.

(Resin Component) The type of the resin component contained in the release layer is not particularly limited. For example, it may be a resin (thermosetting resin) having a property of causing a crosslinking reaction by heating and curing. Examples of the resin which can be used as the resin component include an acrylic resin, an olefin resin, a styrene resin, an acrylonitrile resin, an anthrone resin, an epoxy resin, a cyanate resin, a maleimide resin, and an allyl Nadick.醯imine resin, phenol resin, urea resin, melamine resin, alkyd resin, unsaturated polyester resin, diallyl phthalate resin, resorcinol formaldehyde resin, xylene resin, furan resin, amine group Formate resin, ketone resin, triallyl cyanurate resin, isocyanate resin, resin containing tris(2-hydroxyethyl)isocyanurate, resin containing triallyl trimellitate, A thermosetting resin synthesized by cyclopentadiene or a thermosetting resin formed by trimerization of aromatic dicyandiamide. The resin component contained in the release layer may be one type or two or more types.

The release layer preferably contains at least one selected from the group consisting of an acrylic resin, an olefin resin, a styrene resin, and an acrylonitrile resin as a resin component from the viewpoint of mold release property of the semiconductor package.

The acrylic resin may, for example, be a homopolymer or a copolymer containing at least a (meth)acrylic monomer in a polymerization component. Specific examples thereof include poly(meth)acrylic acid, poly(meth)acrylate, and the like.

Examples of the (meth)acrylic acid monovalent constituting the acrylic resin include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, and n-propyl (meth)acrylate, and (methyl). Isopropyl acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, second butyl (meth)acrylate, tert-butyl (meth)acrylate, butyl (meth)acrylate Ester, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, (methyl) Ethyl acrylate, dodecyl (meth)acrylate, tetradecyl (meth)acrylate, cetyl (meth)acrylate, octadecyl (meth)acrylate, (meth)acrylic acid Decaalkyl ester, behenyl (meth)acrylate, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, benzyl (meth)acrylate, Phenyl (meth)acrylate, methoxyethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, (meth)acrylic acid Dimethylaminopropyl ester (Meth) acrylate, 2-chloroethyl acrylate, (meth) acrylate, 2-fluoro-ethyl (meth) acrylate, cyclopentyl acrylate.

Examples of the monomer other than the (meth)acrylic monomer constituting the acrylic resin include styrene, α-methylstyrene, cyclohexylmaleimide, vinyltoluene, vinyl chloride, and vinyl acetate. N-vinylpyrrolidone, butadiene, isoprene, chloroprene, and the like.

Examples of the olefin resin include a homopolymer of an olefin monomer or an alkene monolith, and a copolymer containing an olefin monomer or an olefinic monomer as a polymerization component. Specific examples thereof include polyolefins such as polyethylene, polypropylene, and polymethylpentene.

Examples of the styrene resin include a homopolymer of styrene or a styrene derivative, a copolymer containing styrene or a styrene derivative as a polymerization component, and the like. Examples of the styrene derivative include α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 2-ethylstyrene, and 3-ethylstyrene. Alkyl-substituted styrene having an alkyl chain such as 4-ethylstyrene, halogen-substituted styrene such as 2-chlorostyrene, 3-chlorostyrene or 4-chlorostyrene, 4-fluorostyrene, 2,5 - Fluorine-substituted styrene such as difluorostyrene, vinyl naphthalene, and the like.

The acrylonitrile resin may, for example, be a homopolymer of a (meth)acrylonitrile monolith or a copolymer containing a (meth)acrylonitrile monolith as a polymerization component.

When a thermosetting resin is used as the resin component, a crosslinking agent can be used. In the case of using a crosslinking agent, the content of the crosslinking agent relative to 100 parts by mass of the thermosetting resin is not particularly limited. For example, the content of the crosslinking agent per 100 parts by mass of the thermosetting resin may be from 1 part by mass to 10 parts by mass.

The type of the crosslinking agent is not particularly limited, and can be selected depending on the type of the thermosetting resin, the desired curing rate, and the like. For example, when an acrylic resin is used as the thermosetting resin, it can be selected from known crosslinking agents such as an isocyanate compound, a melamine compound, and an epoxy compound.

[Filler] The volume average particle diameter of the filler is such that the ratio (A/B) of the volume average particle diameter A (μm) to the mass B (g/m ² ) per 1 m ² of the release layer is 1 or less. Conditions are not particularly limited. For example, it is preferably from 1 μm to 50 μm.

When the volume average particle diameter of the filler is 1 μm or more, sufficient unevenness is formed on the outer surface of the release layer, and the uniformity of the appearance of the surface of the formed semiconductor package is improved, and the flow marks of the sealing material are suppressed. tendency. When the volume average particle diameter of the filler is 50 μm or less, the thickness of the release layer required to suppress the fall of the filler from the release layer tends to be suppressed.

The upper limit of the volume average particle diameter of the filler is preferably 50 μm, more preferably 20 μm, from the viewpoint of the appearance of the surface of the semiconductor package. From the viewpoint of adjusting the surface roughness of the formed semiconductor package, the lower limit of the volume average particle diameter of the filler is preferably 1 μm.

The shape of the filler contained in the release layer is not particularly limited. For example, a spherical shape, an elliptical shape, an amorphous shape, etc. are mentioned.

The filler is not particularly required as long as it can be contained in the release layer in a state in which it retains its form (that is, it is difficult to dissolve in the organic solvent used in the formation of the release layer, the resin component contained in the release layer, etc.). The restriction may be a filler containing an organic substance, a filler containing an inorganic substance, or a filler containing both an organic substance and an inorganic substance. The filler contained in the release layer may be one type or two or more types.

Examples of the inorganic substance to be used as the filler include metals such as silver, gold, and copper, ceria, alumina, titania, and iron oxide. The inorganic substance may or may not have electrical conductivity.

In the case of using a filler containing an inorganic substance, an inorganic ion exchanger can also be used in combination. As an inorganic ion exchanger, it is effective to extract ions (Na ⁺ , K ⁺ , Cl ^- , F ^- , RCOO ^- , Br ^- etc.) extracted in an aqueous solution when the release layer film is extracted in a hot aqueous solution. , R is the capture of alkyl, aryl, etc.). Examples of such inorganic ion exchangers include natural minerals such as zeolites, zeolites, acid clays, dolomites, and hydrotalcites, and synthetic zeolites synthesized by artificial synthesis.

Examples of the organic substance to be used as the filler include an acrylic resin, a quinone imine resin, a guanamine resin, an amidoxime resin, an olefin resin, a styrene resin, a carbonate resin, an anthrone resin, and an acrylonitrile-butadiene. Acrylonitrile Butadiene Styrene (ABS) resin and the like. These resins are preferably in a state of being cured by a crosslinking reaction.

Among the fillers, a filler containing an acrylic resin (hereinafter also referred to as a cross-linking type acrylic resin) in a state of being cured by a crosslinking reaction is excellent in dispersibility of a resin component, and is selected as a polymerization component. The type of the monomer is preferable because it is easy to adjust the properties such as the shape of the filler, the particle diameter, and the heat resistance.

The crosslinked acrylic resin is preferably a (meth) group which does not contain a functional group such as butyl (meth)acrylate, ethyl (meth)acrylate or 2-ethylhexyl (meth)acrylate. Acrylic acid mono-substrate, (meth)acrylic acid mono-substrate having functional groups such as (meth)acrylic acid, (meth)acrylic acid hydroxyethyl ester, (meth)acrylamide, (meth)acrylonitrile or the like Or a (meth)acrylic copolymer obtained by copolymerization of other monomers.

Examples of the (meth)acrylic monomer which is a polymerization component of the crosslinked acrylic resin include (1) a (meth)acrylic monomer having a chain alkyl group and (2) an alicyclic skeleton ( (meth)acrylic acid mono-body, (3) polyfunctional (meth)acrylic acid mono-body, (4) functional group-containing (meth)acrylic monomer, and the like. Hereinafter, the (meth)acrylic acid single body will be described.

(1) A (meth)acrylic acid monomer having a chain alkyl group as a (meth)acrylic acid monomer having a chain hydrocarbon group, and a (meth) acrylate having a chain hydrocarbon group in the ester portion (hereinafter, Also, a (meth)acrylic acid ester is sometimes referred to as (meth)acrylate.

The (meth) acrylate having a chain hydrocarbon group is, for example, a (meth) acrylate having a chain hydrocarbon group having 1 to 20 carbon atoms. When the number of carbon atoms of the hydrocarbon group is 20 or less, it tends to have a low modulus of elasticity. The carbon number is preferably from 2 to 18 in view of the solubility of the acrylic polymer, and the carbon number is more preferably from 4 to 18 from the viewpoint of heat resistance in the molding step. The chain hydrocarbon group is preferably an alkyl group having 1 to 20 carbon atoms.

The chain hydrocarbon group may be linear or branched, and in the case of branching, it preferably does not contain tertiary carbon atoms. By not including a tertiary carbon atom, it is difficult to reduce the mass due to thermal decomposition at a low temperature, and it is advantageous in terms of heat resistance.

Specific examples of the (meth) acrylate having a chain-like hydrocarbon group having 1 to 20 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, and n-propyl (meth)acrylate. Ester, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, second butyl (meth)acrylate, amyl (meth)acrylate, (methyl) ) n-hexyl acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, 1-dodecanol (meth) acrylate, (methyl) ) Isostearyl acrylate and the like.

(2) (Meth)acrylic acid monovalent body having an alicyclic skeleton As the (meth)acrylic acid monovalent body having an alicyclic skeleton, a (meth) acrylate having an alicyclic skeleton can be mentioned. Examples of the alicyclic skeleton include a cycloalkane skeleton, a bicycloalkane skeleton, a norbornene skeleton, and an isobornyl skeleton. Among them, from the viewpoint of improving transparency, a bicycloalkane skeleton and a norbornene skeleton are preferred.

Specific examples of the (meth)acrylic acid monovalent body having an alicyclic skeleton include (meth)acrylate cyclopentyl (meth)acrylate cyclopentyl (meth)acrylate cyclopentyl ester (meth). Acrylate cyclopentanyl), cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, norbornene (meth)acrylate, (meth)acrylic acid Norborn methyl ester, phenyl norbornene (meth)acrylate, cyanonorbornyl (meth)acrylate, isobornyl (meth)acrylate, borneol (meth)acrylate, (meth)acrylic acid Menthyl ester, decyl (meth) acrylate, adamantyl (meth) acrylate, dimethyl adamantyl (meth) acrylate, tricyclo(methyl) acrylate [5.2.1.0 ^2,6 ] 癸-8 - a base ester, a tricyclo[(methyl)) acrylate [5.2.1.0 ^2,6 ] 癸-4-methyl ester, a cyclomethacrylate (meth) acrylate or the like.

From the viewpoint of heat resistance, cyclopentyl acrylate, cyclohexyl acrylate, isobornyl acrylate, norbornyl acrylate, norbornyl acrylate, and tricyclohexyl acrylate [5.2.1.0 ^2,6 ]癸 are ^preferred . -8-yl ester, tricyclo[5.1.02 ^2,6 ]indole-4-methyl ester, adamantyl acrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, methylcyclohexyl methacrylate Ester, trimethylcyclohexyl methacrylate, norbornyl methacrylate, norbornyl methacrylate, isobornyl methacrylate, borneol methacrylate, menthyl methacrylate, methacrylic acid Oxime ester, adamantyl methacrylate, dimethyl hydroxyalkyl methacrylate, tricyclo [5.0.1.02 ^2,6 ] 癸-8-yl methacrylate, tricyclomethacrylate [5.2.1.0 ^{2 , 6} ] 癸-4-methyl ester, cyclodecyl methacrylate, phenyl norbornene methacrylate, and the like.

Further, in terms of high heat resistance, cyclopentyl acrylate, cyclohexyl acrylate, isobornyl acrylate, norbornyl acrylate, acrylonitrile norbornyl methyl ester, acrylic tricyclo[5.2.1.0 ^2,6癸-8-yl ester, tricyclo[5.1.02.0 ^2,6 ] 癸-4-methyl ester, adamantyl acrylate, and the like.

(3) Polyfunctional (meth)acrylic Monomer The polyfunctional (meth)acrylic monomer is not particularly limited as long as it has two or more (meth)acrylinyl groups. Examples of the polyfunctional (meth)acrylic acid monovalent body include a (meth)acrylic acid monomeric body having two or more (meth)acrylonyl groups and an alicyclic skeleton, and two or more (meth) groups. a (meth)acrylic acid mono-body having an acryl fluorenyl group and an aliphatic skeleton, a (meth)acrylic acid mono-body having two or more (meth) acrylonitrile groups and a dioxane glycol skeleton, A (meth)acrylic acid monocomponent having two or more (meth)acryl fluorenyl groups and a functional group which the (meth)acrylic acid mono-substrate having a functional group (4) described later has.

Examples of the polyfunctional (meth)acrylic acid monovalent body include cyclohexane-1,4-dimethanol di(meth)acrylate and cyclohexane-1,3-dimethanol di(meth)acrylate. Tricyclodecane dimethylol di(meth) acrylate (for example, manufactured by Nippon Kayaku Co., Ltd., KAYARAD R-684, tricyclodecane dimethylol diacrylate, etc.) ), tricyclodecane dimethanol di(meth) acrylate (for example, manufactured by Shin-Nakamura Chemical Co., Ltd., A-DCP, tricyclodecane dimethanol diacrylate, etc.), dioxane diol di(a) Acrylate (for example, manufactured by Nippon Kayaku Co., Ltd., KAYARAD R-604, dioxanediol diacrylate, etc.), neopentyl glycol di(meth)acrylate, two Cyclopentyl di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, ethylene oxide modified 1,6-hexanediol di(meth)acrylate, new Pentyl glycol di(meth)acrylate, (poly)ethylene oxide modified neopentyl glycol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, polyethyl b Diol diol Acrylate, polypropylene glycol di(meth)acrylate, ethylene oxide modified bisphenol A type di(meth)acrylate (preferably polyethylene oxide modified bisphenol A type II (A) Acrylate, more preferably ethylene oxide 5 moles to 15 moles modified bisphenol A type di(meth)acrylate) and (poly)ethylene oxide modified phosphoric acid di(meth)acrylic acid Ester and the like.

(4) A (meth)acrylic monomer having a functional group as a (meth)acrylic monomer having a functional group, which may be exemplified by having a carboxyl group, a hydroxyl group, an acid anhydride group, an amine group, or a guanamine group in the molecule. And a (meth)acrylic monocomponent of at least one functional group in the group consisting of epoxy groups.

Examples of the (meth)acrylic mono-unit having a carboxyl group as a functional group include (meth)acrylic acid, 2-(meth)acryloxyethyl succinic acid, and 2-(methyl)acryloxyethyloxy group. Phthalic acid, 2-(meth)acryloxyethyl hexahydrophthalic acid, 2-(meth)acryloxypropylhexahydrophthalic acid, and the like.

Examples of the (meth)acrylic mono-unit having a hydroxyl group as a functional group include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and cyclohexanedimethanol ( Methyl) acrylate, N-methylol (meth) acrylamide, and the like.

Examples of the (meth)acrylic mono-compound having an acid anhydride group as a functional group include trimellitic anhydride (meth) propylene decyloxyethyl ester, cyclohexane tricarboxylic anhydride (methyl) propylene decyloxyethyl ester, and the like.

The mono(meth)acrylic acid group having an amine group as a functional group may, for example, diethylaminoethyl (meth)acrylate or 2,2,6,6-tetramethylpiperidine (meth)acrylate. , (meth) acrylamide, and the like.

Examples of the (meth)acrylic acid monovalent body having a mercapto group as a functional group include N-(meth)acrylonitrile glycine decylamine.

Examples of the (meth)acrylic mono-unit having an epoxy group as a functional group include glycidyl (meth)acrylate, glycidyl α-ethyl (meth)acrylate, and α-n-propyl (meth)acrylic acid. Glycidyl ester, 2-(2,3-epoxypropoxy)ethyl (meth) acrylate, 3-(2,3-epoxypropoxy)propyl (meth) acrylate, 4- (2,3-epoxypropoxy)butyl (meth) acrylate, 5-(2,3-epoxypropoxy)pentyl (meth) acrylate, 6-(2,3-ring Oxypropoxy)hexyl (meth) acrylate, 3,4-epoxybutyl (meth) acrylate, 4,5-epoxypentyl (meth) acrylate, (meth) acrylate-6 , 7-epoxyheptyl ester, α-ethyl (meth)acrylic acid-6,7-epoxyheptyl ester, (meth)acrylic acid-3-methyl-3,4-epoxybutyl ester, (methyl )-4-methyl-4,5-epoxypentyl acrylate, 5-methyl-5,6-epoxyhexyl (meth)acrylate, β-methylglycidyl (meth)acrylate , α-ethyl (meth)acrylic acid-β-methyl glycidyl ester, (meth)acrylic acid-3-methyl-3,4-epoxybutyl ester, (meth)acrylic acid-4-methyl- 4,5-epoxypentyl ester, 5-methyl-5,6-epoxyhexyl (meth)acrylate, and the like.

In the (meth)acrylic acid monomer having a functional group, an acrylic resin obtained by polymerizing a (meth)acrylic mono-compound (preferably glycidyl methacrylate) having an epoxy group as a functional group Since it is excellent in airtightness, it is preferable from the viewpoint of improving the antifouling property of a release film.

(Other monomer) The crosslinked acrylic resin may contain a monomer (other monomer) other than the (meth)acrylic monomer as a polymerization component. Examples of the other monomer include a (meth)acrylic acid monovalent body containing a benzene ring or a hetero ring, an aromatic vinyl compound, a vinyl cyanide compound, an unsaturated dicarboxylic anhydride, and an N-substituted maleimide.

Examples of the (meth)acrylic acid monovalent body containing a benzene ring or a hetero ring include phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, and (methyl). Naphthyl acrylate, tetrahydroxy hydroxy (meth) acrylate, and the like.

Examples of the aromatic vinyl compound include 4-vinylpyridine, 2-vinylpyridine, α-methylstyrene, α-ethylstyrene, α-fluorostyrene, α-chlorostyrene, and α-bromine. Styrene, fluorostyrene, chlorostyrene, bromostyrene, methylstyrene, methoxystyrene, (o-, m-, p-)hydroxystyrene, styrene, and the like.

Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile.

Examples of the unsaturated dicarboxylic acid anhydride include maleic anhydride and the like.

Examples of the N-substituted maleimide group include N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, and N-isopropylmaline. Yttrium, N-butyl maleimide, N-isobutyl maleimide, N-tert-butyl maleimide, N-lauryl maleimide, N-ring Hexylmadanimine, N-benzylmaleimide, N-phenylmaleimide, and the like.

(Crosslinking Agent) The kind of the crosslinking agent used to generate the crosslinking reaction of the crosslinking type acrylic resin is not particularly limited. For example, a known crosslinking agent, such as an isocyanate compound, a melamine compound, and an epoxy compound, is mentioned. In order to form a slowly expanding network structure in the crosslinked acrylic resin, it is preferred to use a polyfunctional crosslinking agent. In the present specification, "polyfunctional" means a trifunctional or higher.

[Substrate] The type of the substrate is not particularly limited. The base material preferably has heat resistance that can withstand a predetermined period of time for heating the mold at the time of molding, and flexibility that can sufficiently follow the structure of the mold. Examples of the substrate having such characteristics include a substrate containing a resin having heat resistance. In the case where the substrate contains a resin, the resin may be used alone or in combination of two or more.

When the sealing material is formed at a high temperature (usually about 100 ° C to 200 ° C), the substrate preferably has heat resistance to withstand the temperature for a predetermined period of time. In addition, in order to suppress the occurrence of wrinkles of the sealing resin, cracking of the release film, and the like when the release film is attached to the mold, it is important to select the elastic modulus, the elongation, and the like at a high temperature.

The base material preferably contains a polyester as a resin from the viewpoint of heat resistance and an elastic modulus at a high temperature. Examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and a resin containing a polymerization component of two or more kinds of these polyesters as a polymerization component. A resin obtained by modifying these polyesters. Among them, it is preferable to contain at least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

The substrate is preferably in the form of a sheet. Specifically, the resin is molded into a sheet shape. From the viewpoint of followability to the mold, a biaxially stretched resin sheet (film) is preferred.

The thickness of the substrate is not particularly limited. For example, it is preferably 1 μm to 100 μm, more preferably 3 μm to 20 μm. When the thickness of the base material is 1 μm or more, the release film is excellent in handleability, and wrinkles are less likely to occur. When the thickness is 100 μm or less, the film has excellent followability to the mold and suppresses generation of wrinkles or the like of the formed semiconductor package.

In the present embodiment, the thickness of the substrate is an average value of the values obtained by measuring five points at an arbitrary position. The thickness of the substrate can be measured, for example, using a general-purpose micrometer.

Since the base material is in contact with the surface of the mold, depending on the material thereof, a larger peeling force is sometimes required in order to peel the release film from the mold. In the case where it is difficult for the substrate to be peeled off from the mold, it is preferred to adjust the substrate so as to be easily peeled off from the mold.

As a method of adjusting the substrate so as to be easily peeled off from the mold, the surface opposite to the surface on the side of the release layer of the substrate (the surface on the side in contact with the mold) is subjected to pear processing equal to the surface. A method of imparting processing to the unevenness, a method of further providing another release layer (second release layer) on the substrate, and the like.

When the second release layer is provided on the substrate, the material of the second release layer is not particularly limited. For example, it can be formed using the same material as that used in the release layer. The thickness of the second release layer is not particularly limited, but is preferably 0.1 μm to 100 μm. The thickness of the second release layer is defined to be the same as the thickness of the release layer.

[Other members] The release film may have a member other than the release layer and the substrate as needed. For example, a member such as an anchor lifting layer, an anchor lifting layer, an antistatic layer, or a colored layer of the release layer or the second release layer may be provided between the release layer and the substrate, or between the substrate and the second release layer. Further, in order to protect the surface of the release film, a protective layer may be provided.

<Method for Producing Release Film> The method for producing the release film is not particularly limited. For example, a composition for forming a release layer is prepared and imparted to one side of the substrate, and if necessary, the volatile component in the composition is removed by drying to form a release layer on the substrate. Make a release film. In this case, the volume average particle diameter A (μm) of the filler contained in the formed release layer can be adjusted by adjusting the amount of the composition imparted to the substrate and the amount of the filler to be used. The ratio (A/B) of the mass B (g/m ² ) per 1 m ² of the mold layer was set to 1 or less.

The preparation method of the composition for forming the release layer is not particularly limited. For example, a resin component, a filler, and a solvent can be mixed and prepared. From the viewpoint of forming a release layer in which thickness unevenness is suppressed on a substrate, it is preferred to use an organic solvent capable of dissolving a resin component as a solvent. Examples of the organic solvent include toluene, methyl ethyl ketone, and ethyl acetate.

The method of imparting the composition to the substrate is not particularly limited. For example, it can be provided by a known coating method such as a roll coating method, a bar coating method, or an anastomosis coating method. When the composition for forming the release layer is applied to the substrate, it is preferably provided so that the thickness of the release layer formed is from 0.1 μm to 100 μm.

The composition to be applied to the substrate can be dried as needed to remove volatile components such as a solvent in the composition. The method of drying is not particularly limited and can be carried out by a known method. Drying can be carried out, for example, at 50 ° C to 150 ° C for 0.1 minutes to 60 minutes.

[Method of Using Release Film] Hereinafter, an example of a method of using the release film of the present embodiment will be described with reference to the drawings. In addition, the size of the members in each drawing is conceptually large, and the relative relationship between the sizes of the members is not limited thereto.

Fig. 1 is a view schematically showing a cross section of a release film in a state in which a functional sheet is held. In FIG. 1, the release film 10 has the base material 1 and the release layer 2, and the functional sheet 3 is arrange|positioned on the mold release layer 2.

FIG. 2 is a cross-sectional view of the apparatus when the release film 10 that is wind-off from the state of being wound is schematically illustrated and molded by a molding apparatus using a transfer molding method. In Fig. 2, reference numeral 4 denotes a mold, and reference numeral 5 denotes a plunger for injecting a sealing resin into a gap in the mold. Reference numeral 6 denotes a support member for a semiconductor package, and in a BGA type package form or the like, a circuit is often provided inside the support member. Reference numeral 7 is a semiconductor wafer, and a circuit on a semiconductor wafer is generally connected to a circuit in a supporting member by a metal wire (not shown) such as gold or copper.

As shown in FIG. 2, the release film 10 is wound up from the roll 8A and placed in the concave portion of the mold 4. At this time, the functional sheet 3 mounted on the release film 10 is also placed in the concave portion of the mold 4. Further, the mold 4 is heated (for example, at about 170 ° C) and set to melt the sealing resin injected in the subsequent step.

FIG. 3 is a view schematically showing a state in which the upper and lower molds 4 are brought into contact with each other, and the sealing resin 9 is injected into the gap in the mold 4 using the plunger 5.

Fig. 4 is a view schematically showing a state in which the upper and lower molds 4 are separated after the molding is completed. As shown in FIG. 4, the functional sheet 3 mounted on the release film 10 is separated from the release film 10 and placed on the semiconductor package. The release film 10 after use is wound around the roll 8B and collected.

Since the functional sheet of the release film of the present embodiment has excellent retention of the functional sheet until the molding step, the functional sheet is placed in the mold without falling off from the release film. Further, in the molding step, the performance of releasing the functional sheet is excellent. Therefore, when the upper and lower molds are separated after the molding is completed, the functional sheet is separated from the release sheet and placed on the semiconductor package. [Examples]

Hereinafter, the present invention will be specifically described with reference to the embodiments. However, the invention is not limited by the embodiments.

<Examples 1 to 10 and Comparative Examples 1 to 7> (Preparation of a composition for forming a release layer) The acrylic resin, the crosslinking agent, and the filler as a resin component are made into a nonvolatile component of each material. The amount (parts by mass) described in Table 1 or Table 2 was mixed with toluene to prepare a toluene solution having a solid content of 15% by mass to prepare a composition for forming a release layer.

As the acrylic resin, a copolymer of acrylate, ethyl acetate, and a 24 mass% toluene solution of n-butyl acrylate (Integrated Chemical Co., Ltd., trade name "S-43") was used. As a crosslinking agent, a 75 mass% toluene solution of an isocyanate compound (Tosoh Corporation, trade name "Coronate L"), and an adduct of hexamethylene diisocyanate are used to modify polyisocyanate. (Asahi Kasei Chemical Co., Ltd., trade name "Duranate AE710-100"). As a filler, particles of a crosslinked acrylic resin which is a copolymer of methacrylate (Comprehensive Chemical Co., Ltd., trade name "MX-150 (volume average particle diameter: 1.5 μm)", "MX-300 (volume) Average particle diameter: 3.0 μm), and "MX-1000 (volume average particle diameter: 10.0 μm)" or cerium oxide particles (volume average particle diameter: 5.0 μm, FUJI Silysia Chemical Co., Ltd. The product name is "Sylosphere C-0809").

(Production of Release Film) The prepared release layer-forming composition was applied to one side of the substrate at a rate of 0.5 m/min to 3 m/min using a roll coater, in this state. The mold was dried in a drying oven having a length of 3 m at 100 ° C to form a release layer on the substrate to obtain a release film. At this time, the gap at the time of coating was adjusted so that the coating amount per 1 m ² of the composition after drying (the mass of the release layer) became the value (g) shown in Table 1 or Table 2.

As the substrate, a biaxially stretched polyethylene terephthalate (PET) film having a thickness of 25 μm (Dupont Teijin Films Co., Ltd., trade name "FT3-25" was used. "), and the biaxially stretched polybutylene terephthalate (PBT) film (Dakura Industry Co., Ltd.) for corona treatment.

(Measurement of mass of release layer) The produced release film was cut into a size of 10 cm × 10 cm to measure the mass. Thereafter, the release layer was removed using methyl ethyl ketone, the mass was measured again after air drying, and the quality of the release layer was calculated from the difference in mass before and after. The obtained value was multiplied by 100, and the mass (g/m ² ) of the release layer per 1 m ² was calculated. The results are shown in Table 1 or Table 2.

(Measurement of Adhesion) The release film was placed on a viscosity tester (manufactured by Rhesca) under the trade name "TAC-II" by measuring the contact between the probe and the release layer during measurement. ). Thereafter, the viscosity (gf) was measured using a probe having a diameter of 5 mm at a probe lowering speed of 120 mm/min, a pre-measurement load: 10 gf, and a rising speed at the time of measurement: 600 mm/min. The measurement of the adhesive force was carried out at a temperature (25 ° C) assumed for room temperature and a temperature (170 ° C) assumed for the molding step. The results are shown in Table 1 or Table 2.

(Evaluation of Retention Property) In order to evaluate the ability of a release film to hold a functional sheet, the following test was performed. The produced release film was cut into a size of 15 cm × 30 cm, and 50 cm × 100 cm of dust-free paper was attached to the release layer of the cut release film using an anthrone rubber roller. Thereafter, the paper was placed on the stage with the dust-free paper under the environment at 25 ° C, and the end of the release film was lifted by 50 cm to 100 cm in the direction of 90° to observe whether the adhered dust-free paper was peeled off. The case where the dust-free paper was not peeled off was set to "OK", and the case where peeling was performed was "NG", and the result is shown in Table 1 or Table 2.

(Evaluation of surface roughness) Using a surface roughness measuring device (Otaru Research Institute Co., Ltd., model SE-3500), the tip diameter of the stylus was 2 μm, the conveying speed was 0.5 mm/s, and the scanning distance was 8 mm. The conditions were measured, and the measured results were analyzed by JIS B0601 (2013) or ISO 4287 (1997) to obtain an arithmetic mean roughness (Ra) and a ten-point average roughness (Rz) of the outer surface of the release layer. The results are shown in Table 1 or Table 2.

<Comparative Example 8> An Ethylene Tetra Fluoro Ethylene (ETFT) film which is widely used as a release film by a compression molding method (Asahi Glass Co., Ltd., trade name: "Afulex" Aflex) 50HK") was evaluated in the same manner as in the examples. The results are shown in Table 2. Further, since Aflex 50HK does not have a resin layer (release layer), the measurement of the quality of the release layer is not performed.

[Table 1]

[Table 2]

As shown in Table 1, the ratio (A/B) of the volume average particle diameter A (μm) of the filler to the mass B (g/m ² ) per 1 m ² of the release layer was 1 or less. In the release film of 1 to 10, the adhesive strength at 25 ° C was high, and the peeling of the dust-free paper was not observed in the evaluation test of the retention property, and the retention property was excellent. On the other hand, it was found that the adhesive strength at 170 ° C was low and the mold release property was good in the molding step. Further, it has been found that even if the surface roughness is changed by adjusting the type and content of the filler contained in the release layer, good results can be obtained, so that desired characteristics can be maintained and the combination of the material and the package of the release film can be dealt with. diversification.

The release film of Comparative Example 1 to Comparative Example 7 in which the ratio (A/B) of the volume average particle diameter A (μm) of the filler to the mass B (g/m ² ) per 1 m ² of the release layer exceeded 1 The adhesive strength at 25 ° C was remarkably low, and the peeling of the dust-free paper was also observed in the evaluation test of the retention property, and the retention was inferior to the examples.

The adhesive force of Aflex 50HK used as a release film of Comparative Example 8 at 25 ° C and the adhesive strength at 170 ° C were both low, and the mold release property was excellent. However, the peeling of the dust-free paper was observed in the evaluation test of the retention property, and the retention property was inferior to that of the examples.

From the above results, it is understood that the performance of the functional sheet of the release film of the present embodiment up to the molding step is excellent in the performance of releasing the functional sheet during the molding step.

The disclosure of Japanese Patent Application No. 2016-101820 is incorporated herein by reference in its entirety. All the documents, patent applications, and technical specifications described in the specification are specifically and individually described as being incorporated by reference to the respective documents, patent applications, and technical specifications. To this manual.

1‧‧‧Substrate

2‧‧‧ release layer

3‧‧‧ functional sheets

4‧‧‧Mold

5‧‧‧Plunger

6‧‧‧Support members

7‧‧‧Semiconductor wafer

8A, 8B‧‧ ‧ volumes

9‧‧‧ Sealing resin

10‧‧‧ release film

FIG. 1 is a view schematically showing a cross section of a release film in a state in which a functional sheet is held. Fig. 2 is a view schematically showing a cross section of an apparatus when a release film is used and molded by a transfer molding method. Fig. 3 is a view schematically showing a cross section of an apparatus when a release film is used and molded by a transfer molding method. Fig. 4 is a view schematically showing a cross section of an apparatus when a release film is used and molded by a transfer molding method.

Claims (6)

A release film having: a substrate; and a release layer disposed on the substrate and comprising a resin component and a filler; a volume average particle diameter A (μm) of the filler and the release layer The ratio (A/B) of mass B (g/m ² ) per 1 m ² is 1 or less. The release film according to claim 1, wherein the filler has a volume average particle diameter A of from 1 μm to 50 μm. The release film according to claim 1 or 2, wherein the release layer has a mass B per 1 m ² of from 0.1 g/m ² to 100 g/m ² . The release film according to any one of claims 1 to 3, wherein the resin component contains a thermosetting resin. The release film according to any one of claims 1 to 4, further comprising a crosslinking agent, wherein the content of the crosslinking agent is 1 part by mass based on 100 parts by mass of the resin component. ~10 parts by mass. The release film according to any one of claims 1 to 5, wherein the substrate comprises a material selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, and polynaphthalene. At least one of the group consisting of ethylene diformate.