Semiconductor encapsulating material composition

Abstract

To provide a semiconductor encapsulating material composition that enables formation of a semiconductor encapsulating material exhibiting low thermal expansion, excellent water resistance, and excellent melt fluidity under heating.SOLUTION: A semiconductor encapsulating material composition comprises: 0.1-5 mass% of a polymer having a weight-average molecular weight of 3,000-100,000 and containing, as constitutional units, 10-100 mol% of a monomer (A) represented by formula (1) and 0-90 mol% of a hydroxyl-containing (meth)acrylate (B) represented by formula (2); 1-15 mass% of an epoxy resin; and 63-97 mass% of inorganic particles. (In formula (1), R1 is hydrogen or a methyl group, and R2 denotes -O- or -NH-.) CH2=CR3-COO-R4 (2). (In formula (2), R3 denotes a hydrogen atom or a methyl group, and R4 denotes a hydroxyalkyl group having 1-4 carbon atoms.)SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a semiconductor encapsulant composition containing a polymer. [Background technology]

[0002] Molding methods such as transfer molding are used to encapsulate semiconductors, in which a composition consisting of inorganic fillers such as silica, epoxy resin, and a curing agent is mixed at high temperatures and poured into a mold as a fluid slurry to harden. In this process, good fluidity is required, as poor fluidity of the slurry will prevent it from reaching the edges, resulting in molding defects.

[0003] In recent years, semiconductor packages have become smaller and thinner as semiconductor integration increases and devices become smaller. As the encapsulant becomes thinner, warping and cracking due to thermal expansion during encapsulation formation become more likely, so an even lower thermal expansion coefficient is required. At the same time, as the encapsulant becomes thinner, dimensional changes and package strength reduction in high temperature and humidity environments, as well as the impact of minute elution due to moisture, become more pronounced. Even minute changes can lead to semiconductor element malfunctions, so excellent water resistance is also required as the encapsulant becomes smaller and thinner.

[0004] Patent Document 1 describes an epoxy resin composition for molding optical components, which contains as essential ingredients (A) a specific epoxy resin, (B) a specific phenolic resin, and silica and / or alumina having different average particle size ranges, with the chemical equivalent ratio of components (A) and (B), the blending ratio of the silicas and / or alumina having different average particle size ranges, and the total amount of silica and / or alumina being a specified content. Although this epoxy resin composition is not intended for use as a semiconductor encapsulant, it has a similar composition and challenges, such as dispersing silica and / or alumina in an epoxy resin and a phenolic resin, and achieving low expansion for high-precision molding.

[0005] Patent Document 2 describes a semiconductor encapsulation resin composition that contains an epoxy resin, a phenolic resin curing agent, a curing accelerator, and an alumina powder, and that has high thermal conductivity and low alpha rays, with the cured product having an alpha dose and a predetermined thermal conductivity within a predetermined range. Patent Document 2 also describes a low-stress agent such as a silicone compound as an example of an additive that may be contained in this semiconductor encapsulation resin composition.

[0006] It is believed that low thermal expansion can be achieved in encapsulating materials by using the epoxy resin composition described in Patent Document 1 and the resin composition for semiconductor encapsulation containing a low-stress agent as described in Patent Document 2. However, with these resin compositions, there is concern that as layers become thinner in the future, molding defects may occur due to insufficient fluidity when molding using thinner molds, making it difficult to achieve both low thermal expansion and fluidity. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-292734 [Patent Document 2] Japanese Patent Application Publication No. 2023-109966 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a semiconductor encapsulant composition which can form a semiconductor encapsulant having low thermal expansion and excellent water resistance, and which also has excellent flowability when heated. [Means for solving the problem]

[0009] As a result of investigations aimed at solving the above problems, the present inventors have found that the above problems can be solved by using a specific polymer. That is, the present invention relates to the following semiconductor encapsulation material composition.

[0010] A semiconductor encapsulant composition comprising 0.1 to 5 mass% of a polymer having a weight average molecular weight of 3,000 to 100,000, the polymer comprising, as constituent units, 10 to 100 mol% of a monomer (A) represented by the following formula (1) and 0 to 90 mol% of a hydroxyl group-containing (meth)acrylate (B) represented by the following formula (2), 1 to 15 mass% of an epoxy resin, and 63 to 97 mass% of inorganic particles:

[0011] [ka]

[0012] (In formula (1), R 1 is hydrogen or a methyl group, and R 2 represents -O- or -NH-.)

[0013] CH2=CR 3 -COO-R 4 ···(2)

[0014] (In formula (2), R 3 represents a hydrogen atom or a methyl group, and R 4 represents a hydroxyalkyl group having 1 to 4 carbon atoms. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a semiconductor encapsulant composition that can form a semiconductor encapsulant having low thermal expansion and excellent water resistance, and that has excellent fluidity when heated. DETAILED DESCRIPTION OF THE INVENTION

[0016] In this specification, "(meth)acrylic" is a generic term that includes acrylic and methacrylic, "(meth)acrylate" is a generic term that includes acrylate and methacrylate, and "(meth)acrylonitrile" is a generic term that includes acrylonitrile and methacrylonitrile.

[0017] <Semiconductor encapsulant composition> A semiconductor encapsulant composition according to an embodiment of the present invention contains, as structural units, 10 to 100 mol % of a monomer (A) represented by the following formula (1) and 0 to 90 mol % of a hydroxyl group-containing (meth)acrylate (B) represented by the following formula (2), and contains 0.1 to 5 mass % of a polymer having a weight average molecular weight of 3,000 to 100,000, 1 to 15 mass % of an epoxy resin, and 63 to 97 mass % of inorganic particles.

[0018] [ka]

[0019] (In formula (1), R 1 is hydrogen or a methyl group, and R 2 represents -O- or -NH-.)

[0020] CH2=CR 3 -COO-R 4 ···(2)

[0021] (In formula (2), R 3 represents a hydrogen atom or a methyl group, and R 4 represents a hydroxyalkyl group having 1 to 4 carbon atoms.

[0022] Hereinafter, each component contained in the semiconductor encapsulant composition according to the embodiment of the present invention will be described.

[0023] [Polymer] The polymer usable in the embodiment of the present invention contains, as structural units, 10 to 100 mol % of the monomer (A) represented by the above formula (1) and 0 to 90 mol % of the monomer (B) represented by the above formula (2). The weight-average molecular weight of the polymer is 3,000 to 100,000.

[0024] The polymer may be a homopolymer composed only of structural units derived from monomer (A), or a copolymer composed only of structural units derived from monomers (A) and (B). Furthermore, the polymer may contain, in addition to monomers (A) and (B), structural units derived from monomer (C) copolymerizable with monomers (A) and (B). That is, the polymer may be a copolymer composed of structural units derived from monomers (A), (B), and (C). The copolymer may be in any form, such as a random copolymer, a block copolymer, or an alternating copolymer. Random copolymers are particularly preferred.

[0025] Each monomer will be described below.

[0026] [Monomer (A)] The monomer (A) used in the embodiment of the present invention may be a (meth)acrylate having a hydroxyphenyl group represented by the above formula (1). When the polymer used in the embodiment of the present invention contains such a monomer (A) as a constituent monomer, it becomes possible to impart good fluidity to a semiconductor encapsulant composition containing an epoxy resin or the like when heated. The monomer (A) may be used alone or in combination of two or more.

[0027] In formula (1), R 1 may be a hydrogen atom or a methyl group, and is preferably a methyl group from the viewpoint of ease of polymerization control.

[0028] In formula (1), R 2 may be -O- or -NH-. From the viewpoint of cost and availability, -O- is preferred.

[0029] The content of the structural units derived from monomer (A) during polymerization may be 10 to 100 mol %, preferably 30 to 90 mol %, and more preferably 60 to 80 mol %, relative to 100 mol % of the total of the structural monomers. By adjusting the content of the structural units derived from monomer (A) within the above range, the fluidity of the semiconductor encapsulant composition containing the polymer can be improved and thermal expansion of the semiconductor encapsulant can be suppressed. The content of the structural units derived from monomer (A) can be calculated from the blending ratio of the monomers during production of the polymer.

[0030] [Monomer (B)] The monomer (B) used in the embodiment of the present invention may be a hydroxyl group-containing (meth)acrylate represented by the formula (2), more specifically, a hydroxyalkyl (meth)acrylate. When the polymer used in the embodiment of the present invention contains such a monomer (B) as a constituent monomer, the thermal expansion of the semiconductor encapsulant obtained from the semiconductor encapsulant composition can be more effectively suppressed.

[0031] In formula (2), R 3 is a hydrogen atom or a methyl group, and is preferably a methyl group from the viewpoint of ease of controlling polymerization.

[0032] In formula (2), R 4 is a hydroxyalkyl group having 1 to 4 carbon atoms. Examples of such a hydroxyalkyl group include a 2-hydroxyethyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, a 2-hydroxybutyl group, and a 4-hydroxybutyl group. From the viewpoint of suppressing the thermal expansion of the semiconductor encapsulant obtained from the semiconductor encapsulant composition, R 4 The number of carbon atoms in the alkyl group constituting R is preferably 2 to 3, and more preferably 2. 4 The monomer (B) may be linear or branched, but is preferably linear. The monomer (B) may be used singly or in combination of two or more.

[0033] The content of the structural units derived from monomer (B) in the polymer may be 0 to 90% by mass, preferably 10 to 50% by mass, and more preferably 20 to 40% by mass, relative to 100% by mass of the total of the structural monomers. By adjusting the content of the structural units derived from monomer (B) within the above range, it is possible to improve the suppression of thermal expansion of a semiconductor encapsulant obtained from a semiconductor encapsulant composition containing the polymer. The content of the structural units derived from monomer (B) can be calculated from the blending ratio of the monomers during the production of the polymer. [Monomer (C)] Polymers that can be used in embodiments of the present invention may contain a monomer (C) in addition to the monomers (A) and (B). The monomer (C) may be any monomer copolymerizable with the monomers (A) and (B), and may be, for example, a vinyl compound other than the monomers (A) and (B). Examples of such vinyl compounds include styrene-based monomers such as styrene, vinyltoluene, and α-methylstyrene; N-alkylmaleimides such as N-methylmaleimide, N-butylmaleimide, and N-cyclohexylmaleimide; N-arylmaleimides such as N-phenylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-methoxyphenylmaleimide, and N-tribromophenylmaleimide; polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, methoxypolyethylene glycol (meth)acrylate, and methoxypolypropylene glycol. Examples of suitable vinyl monomers include polyalkylene glycol (meth)acrylates such as (meth)acrylates; alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; fluorine-containing vinyl monomers such as perfluoroethylene, perfluoropropylene, and vinylidene fluoride; chlorine-containing vinyl monomers such as vinyl chloride, vinylidene chloride, and allyl chloride; cyano group-containing vinyl monomers such as (meth)acrylonitrile; carbamoyl group-containing vinyl monomers such as (meth)acrylamide; and vinyl esters such as vinyl acetate and vinyl benzoate. Among these, styrene-based monomers, N-alkylmaleimides, polyalkylene glycol (meth)acrylates, and alkyl (meth)acrylates are preferred, and N-alkylmaleimides are more preferred.

[0034] The content of the structural units derived from monomer (C) in the polymer is preferably 0 to 40% by mass, relative to 100% by mass of the total of the structural monomers. When the content of the structural units of monomer (C) is more than 0%, the content of monomer (C) may be within a range in which its function is exhibited, and can be appropriately determined depending on the types of monomers (A) and (B). The content of the structural units derived from monomer (C) can be calculated from the blending ratio of the monomers during the production of the polymer.

[0035] [Weight average molecular weight of polymer (Mw)] The weight-average molecular weight of the polymer is 3,000 to 100,000, preferably 3,000 to 50,000, and more preferably 5,000 to 30,000. If the weight-average molecular weight of the polymer is lower than 3,000, low thermal expansion and water resistance may be insufficient, while if the weight-average molecular weight is higher than 100,000, the viscosity may increase, resulting in poor flowability. The weight-average molecular weight of the polymer can be determined in polystyrene equivalent terms using gel permeation chromatography (GPC).

[0036] [Polymer manufacturing method] The polymer can be produced, for example, by radically polymerizing the monomers in the presence of a polymerization initiator. Examples of the polymerization method include solution polymerization, suspension polymerization, and emulsion polymerization. Among these, solution polymerization is preferred because it is easy to adjust the weight-average molecular weight of the polymer to fall within the preferred range.

[0037] Known polymerization initiators can be used. Examples of the polymerization initiator include organic peroxides and azo compounds. The polymerization initiators may be used alone or in combination of two or more.

[0038] Examples of organic peroxides include cumyl peroxyneodecanoate, tert-butyl peroxyneodecanoate, tert-hexyl peroxypivalate, methyl ethyl ketone peroxide, 2,5-dimethylhexane-2,5-dihydroperoxide, tert-butylcumyl peroxide, dicumyl peroxide, and α,α'-bis(tert-butylperoxy-m-isopropyl)benzene.

[0039] Examples of azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2-(carbamoylazo)isobutyronitrile, 2-phenylazo-4-methoxy-2,4-dimethyl-valeronitrile, 2,2'-azobis(2-methyl-N-phenylpropionamidine) dihydrochloride, 2,2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis(2-methylpropionamide) dihydrate, and 2,2'-azobis(2,4,4-trimethylpentane).

[0040] From the viewpoint of compatibility with the epoxy resin contained in the semiconductor encapsulant composition, it is preferable to use a polymerization initiator containing a cyclic structure, and more preferable are those containing a benzene ring such as cumyl peroxy neodecanoate, tert-butylcumyl peroxide, dicumyl peroxide, and α,α'-bis(tert-butylperoxy-m-isopropyl)benzene.

[0041] The amount of polymerization initiator used can be appropriately set depending on the combination of monomers used, reaction conditions, etc. The method for adding the polymerization initiator and monomers to the reactor is not particularly limited. For example, the entire amount of the polymerization initiator and monomers may be added to the reactor at once, or the polymerization initiator and monomers may be added to the reactor in portions (e.g., dropwise).

[0042] The solvent used in the solution polymerization is not particularly limited as long as it can dissolve the monomer and the polymerization initiator. Examples of the solvent include 2-propanol, n-butanol, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate.

[0043] When solution polymerization is carried out, the total concentration of each monomer in the solution is preferably 10 to 60% by mass, more preferably 20 to 50% by mass. If the total concentration is too low, the monomers tend to remain after polymerization, which may result in a decrease in the weight-average molecular weight of the resulting polymer. If the total concentration is too high, the molecular weight may become too high, and it may become difficult to control heat generation during polymerization.

[0044] The polymerization temperature can be set appropriately depending on the type of monomer, type of polymerization initiator, type of solvent, etc. The polymerization temperature is, for example, 50°C to 120°C. The polymerization time can be set appropriately depending on the type of polymerization initiator, polymerization temperature, etc. For example, when cumyl peroxy neodecanoate is used as the polymerization initiator and the polymerization temperature is 70°C, the polymerization time is, for example, about 5 hours.

[0045] For example, the polymer solution obtained by solution polymerization is dried under reduced pressure to remove the solvent, thereby isolating the polymer, which can be used in the production of a semiconductor encapsulant composition.

[0046] The polymers used in the embodiments of the present invention may be used alone or in combination of two or more. From the viewpoint of molding stability of the semiconductor encapsulant composition, the content of the polymer is 0.1 to 5 mass %, more preferably 0.5 to 2 mass %, and even more preferably 0.7 to 1.3 mass % of the total semiconductor encapsulant composition.

[0047] [Epoxy resin] As the epoxy resin used in the embodiment of the present invention, any monomer, oligomer, or polymer having two or more epoxy groups in one molecule can be used, and there are no limitations on the molecular weight or molecular structure.

[0048] Examples of epoxy resins include: Biphenyl type epoxy resin; Bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and tetramethylbisphenol F-type epoxy resins; polyfunctional epoxy resins such as stilbene-type epoxy resins, novolac-type epoxy resins such as phenol novolac-type epoxy resins and cresol novolac-type epoxy resins, trisphenol-type epoxy resins exemplified by triphenolmethane-type epoxy resins and alkyl-modified triphenolmethane-type epoxy resins; phenol aralkyl type epoxy resins such as phenol aralkyl type epoxy resins having a phenylene skeleton, naphthol aralkyl type epoxy resins having a phenylene skeleton, phenol aralkyl type epoxy resins having a biphenylene skeleton, and naphthol aralkyl type epoxy resins having a biphenylene skeleton; naphthol-type epoxy resins such as dihydroxynaphthalene-type epoxy resins and epoxy resins obtained by glycidyl etherifying dihydroxynaphthalene dimers; Triazine nucleus-containing epoxy resins such as triglycidyl isocyanurate and monoallyl diglycidyl isocyanurate; Examples include bridged cyclic hydrocarbon compound-modified phenolic epoxy resins such as dicyclopentadiene-modified phenolic epoxy resins. These may be used alone or in combination of two or more.

[0049] Among these, it is preferable to include one or more types selected from biphenyl-type epoxy resins, bisphenol-type epoxy resins, polyfunctional epoxy resins, and phenol aralkyl-type epoxy resins, and it is more preferable to include biphenyl-type epoxy resins and polyfunctional epoxy resins.

[0050] From the viewpoint of molding stability of the semiconductor encapsulant composition, the content of the epoxy resin may be 1 to 25 mass % of the entire semiconductor encapsulant composition, preferably 3 to 20 mass %, more preferably 5 to 15 mass %.

[0051] [Hardening agent] The semiconductor encapsulant composition according to the embodiment of the present invention may contain a curing agent. The curing agent is not particularly limited, and a curing agent generally used as an epoxy resin curing agent can be used, for example, an amine-based curing agent, an acid anhydride-based curing agent, a phenol-based curing agent, etc.

[0052] Specific examples of amine-based curing agents include aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), and metaxylylenediamine (MXDA); aromatic polyamines such as diaminodiphenylmethane (DDM) and m-phenylenediamine (MPDA); and polyamine compounds such as dicyandiamide (DICY) and organic acid dihydralazide.

[0053] Specific examples of acid anhydride curing agents include alicyclic acid anhydrides such as hexahydrophthalic anhydride (HHPA) and methyltetrahydrophthalic anhydride (MTHPA), and aromatic acid anhydrides such as trimellitic anhydride (TMA) and benzophenonetetracarboxylic acid (BTDA).

[0054] Specific examples of phenol-based curing agents include novolac-type phenolic resins such as phenol novolac resin and cresol novolac resin; polyfunctional phenolic resins such as phenolic resins having a triphenylmethane skeleton; modified phenolic resins such as terpene-modified phenolic resin and dicyclopentadiene-modified phenolic resin; phenol aralkyl-type phenolic resins such as phenol aralkyl resins having a phenylene skeleton and / or biphenylene skeleton and naphthol aralkyl resins having a phenylene and / or biphenylene skeleton; and the like.

[0055] Other examples include polymercaptan compounds such as thioesters and thioethers, isocyanate compounds such as isocyanate prepolymers and blocked isocyanates, and organic acids such as carboxylic acid-containing polyester resins.

[0056] These curing agents may be used alone or in combination of two or more.

[0057] When a curing agent is used, its content is preferably 1 to 25 mass %, more preferably 3 to 20 mass %, and even more preferably 5 to 15 mass %, of the entire semiconductor encapsulant composition, from the viewpoint of molding stability of the semiconductor encapsulant composition.

[0058] [Curing accelerator] The semiconductor encapsulant composition according to the embodiment of the present invention may contain a curing accelerator. The curing accelerator is not limited as long as it accelerates the curing reaction of the epoxy resin, and can be selected depending on the type of epoxy resin, etc. Specific examples of such curing accelerators include: phosphorus atom-containing compounds such as organic phosphines such as triphenylphosphine, tetra-substituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, and adducts of phosphonium compounds and silane compounds; Examples include imidazole compounds such as 2-methylimidazole, 2-ethyl-4-methylimidazole (EMI24), 2-phenylimidazole (2PZ), and 1-benzyl-2-phenylimidazole (1B2PZ), as well as amidines and tertiary amines such as 1,8-diazabicyclo[5.4.0]undecene-7 and benzyldimethylamine.

[0059] The curing accelerator may be used alone or in combination of two or more.

[0060] When a curing accelerator is used, its content is preferably 0.1 to 2 mass %, more preferably 0.1 to 1 mass %, and even more preferably 0.1 to 0.5 mass %, of the entire semiconductor encapsulant composition, from the viewpoint of molding stability of the semiconductor encapsulant composition.

[0061] [Inorganic particles] As the inorganic particles used in the semiconductor encapsulant composition according to the embodiment of the present invention, those used in semiconductor encapsulants can be applied.

[0062] Specific examples of inorganic particles include silica such as synthetic spherical silica, fused crushed silica, fused spherical silica, crystalline silica, secondary agglomerated silica, and finely divided silica, alumina, silicon nitride, aluminum nitride, boron nitride, titanium oxide, silicon carbide, metal compounds such as aluminum hydroxide, magnesium hydroxide, and titanium white, talc, clay, mica, and glass fiber. Among the specific examples, silica such as synthetic spherical silica, fused crushed silica, fused spherical silica, crystalline silica, secondary agglomerated silica, and finely divided silica is preferably used, and synthetic spherical silica and fused spherical silica are more preferably used.

[0063] The inorganic particles may be used alone or in combination of two or more kinds.

[0064] The inorganic particles have an average particle size D50 of preferably 1.0 μm or more, more preferably 5.0 μm or more, from the viewpoint of suppressing shrinkage during molding. Furthermore, from the viewpoint of improving filling properties during molding, the inorganic particles have an average particle size D50 of preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 15 μm or less. Here, the average particle size D50 of the inorganic particles is the average particle size measured using a commercially available laser particle size distribution analyzer (e.g., SALD-7000 manufactured by Shimadzu Corporation).

[0065] From the viewpoint of suppressing thermal expansion, the content of the inorganic particles may be 63 to 97 mass % of the entire semiconductor encapsulant composition, preferably 70 to 93 mass %, and more preferably 77 to 90 mass %.

[0066] [Other ingredients] The semiconductor encapsulant composition according to the embodiment of the present invention may contain other components different from the polymer, epoxy resin, curing agent, curing accelerator, and inorganic particles described above, as long as the effects of the present invention are not impaired. The other components may be used singly or in combination of two or more.

[0067] Examples of other components include coupling agents, heat resistance improvers, mold release agents, flame retardants, colorants, neutralizers, etc. The total content of other components is preferably 0 to 10% by mass, more preferably 0 to 7% by mass, and even more preferably 0 to 5% by mass, based on the entire semiconductor encapsulant composition.

[0068] [Method of manufacturing semiconductor encapsulant composition] The semiconductor encapsulant composition according to an embodiment of the present invention can be produced by mixing the polymer, epoxy resin, and inorganic particles described above, and, if necessary, the curing agent, curing accelerator, and other components. The method for mixing the components is not particularly limited; all components may be mixed simultaneously, or each component may be added sequentially and mixed. From the viewpoint of uniform mixing, a method in which a mixture of a polymer, an epoxy resin, and other optional components is melt-kneaded, and then the inorganic particles are added and kneaded uniformly is preferred, and it is more preferred to add the inorganic particles in multiple batches and knead them. The conditions for mixing and kneading can be appropriately set according to standard methods, taking into account the types and blending ratios of the various components.

[0069] The semiconductor encapsulant composition according to the embodiment of the present invention can be molded and cured using a molding machine used in the technical field to function as a semiconductor encapsulant. The semiconductor encapsulant composition containing the polymer described above has excellent fluidity and moldability when heated, and the semiconductor encapsulant obtained as a cured product has low thermal expansion and good water resistance. In this way, the semiconductor encapsulant composition can satisfactorily achieve both fluidity, low thermal expansion, and water resistance. These properties can be evaluated, for example, by the method described in the Examples section below. [Example]

[0070] Hereinafter, the embodiments of the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples.

[0071] The monomers used in the synthesis of polymers 1 to 19 and silicones A and B used in comparative examples 4 and 5, which will be described later, are shown below. <Monomer (A)> 4-Hydroxyphenyl methacrylate: Shounol ARP-029P, manufactured by Resonac Co., Ltd. N-(4-hydroxyphenyl)methacrylamide: HMAd manufactured by Osaka Organic Chemical Industry Co., Ltd. <Monomer (B)> 2-Hydroxyethyl methacrylate: NOF Corporation, Blenmer E 2-Hydroxyethyl acrylate: 2-Hydroxyethyl acrylate manufactured by Tokyo Chemical Industry Co., Ltd. 2-Hydroxypropyl methacrylate: NOF Corporation, Blenmer P 2-Hydroxybutyl acrylate: Osaka Organic Industry Co., Ltd., 4HBA <Monomer (C)> Styrene: NS Styrene Monomer Co., Ltd. PME-200: Methoxypolyethyleneglycol methacrylate, NOF Corporation, Blenmar PME-200 Butyl methacrylate: NOF Corporation, Blemmer BMA Cyclohexylmaleimide: N-cyclohexylmaleimide, manufactured by Nippon Shokubai Co., Ltd., Imilex-C

[0072] Silicone A: Polyoxyalkylene-modified silicone oil, manufactured by Shin-Etsu Silicone Co., Ltd., product name X-22-4272 Silicone B: Silicone resin, manufactured by Shin-Etsu Silicone Co., Ltd., KR-480

[0073] [Synthesis Example 1] (Synthesis of Polymer 1) A 1-L separable flask equipped with a stirrer, thermometer, condenser, dropping funnel, and nitrogen gas inlet tube was charged with 150 g of propylene glycol monomethyl ether as a solvent, and the atmosphere inside the flask was replaced with nitrogen to create a nitrogen atmosphere. A monomer solution containing 125 g of hydroxyphenyl methacrylate as monomer (A) dissolved in 120 g of propylene glycol monomethyl ether was prepared, and a polymerization initiator solution containing 25 g of propylene glycol monomethyl ether as a solvent and 25 g of cumyl peroxyneodecanoate (Percumyl ND, manufactured by NOF Corporation) as a polymerization initiator was also prepared. The temperature inside the reaction vessel was raised to 70°C, and the monomer solution and the polymerization initiator solution were simultaneously added dropwise to a 1 L separable flask over 2 hours. The reaction mixture was then reacted at 70°C for 3 hours to obtain a propylene glycol monomethyl ether solution of polymer A. The propylene glycol monomethyl ether solution of polymer 1 was heated to 80±10°C and dried under reduced pressure at a vacuum of 100±50 torr (13.3±6.7 kPa) to distill off the solvent, thereby isolating polymer 1. The weight-average molecular weight of the obtained polymer 1 was measured by the method described below.

[0074] [Synthesis Examples 2 to 19] (Synthesis of Polymers 2 to 19) Polymers 2 to 19 were obtained in the same manner as in Example 1, except that the blending ratios of monomers (A) to (C) were as shown in Tables 1 and 2. The weight-average molecular weights of the obtained polymers 2 to 19 were measured by the method described below. The measurement results are shown in Tables 1 and 2.

[0075] [Measurement of weight-average molecular weight] The weight average molecular weight of each of Polymers 1 to 19 was determined using gel permeation chromatography (GPC) under the following conditions. Equipment: Tosoh Corporation, HLC-8220 Column: Shodex LF-804, manufactured by Resonac Co., Ltd. Standard material: polystyrene Eluent: THF (tetrahydrofuran) Flow rate: 1.0ml / min Column temperature: 40℃ Detector: RID (refractive index detector)

[0076] [Example 1] (Preparation of semiconductor encapsulant composition 1) 0.63 g of polymer 1 obtained in Synthesis Example 1, 3.14 g of biphenyl-type epoxy resin (manufactured by Mitsubishi Chemical Corporation, YX4000H) as an epoxy resin, 3.14 g of phenol novolac-type epoxy resin (manufactured by Epiclon N-775), and 0.095 g of triphenylphosphine (manufactured by Tokyo Chemical Industry Co., Ltd.) as a curing accelerator were kneaded in a mortar, placed in a stainless steel tray, melted on a hot plate heated to 110 °C, and uniformly mixed with a spatula. Approximately 1 / 4 of 43.0 g of silica (manufactured by Denka Co., Ltd., Denka Fused Silica FB-15D, spherical) was added to the resulting melt and uniformly mixed with a spatula. This silica addition procedure was repeated approximately four times to obtain semiconductor encapsulant composition 1 in which all silica and other components were uniformly mixed.

[0077] [Examples 2 to 17, Comparative Examples 1 to 5] (Preparation of Semiconductor Encapsulant Compositions 2 to 22) Semiconductor encapsulant compositions 2 to 22 were obtained in the same manner as in Example 1, except that the amounts of polymers 2 to 19 and silicones A and B added were adjusted to the mass ratios shown in Tables 1 and 2 based on the amount of polymer 1 added in Example 1.

[0078] [Rating 1] (Liquidity assessment) The fluidity of semiconductor encapsulant compositions 1 to 22 is influenced by the resin mixture of the component composition excluding the curing accelerator and silica from the respective component compositions of semiconductor encapsulant compositions 1 to 22. Therefore, the fluidity of semiconductor encapsulant compositions 1 to 22 when heated was evaluated using the resin mixture. The fluidity was also evaluated by measuring the shear viscosity of the resin mixture.

[0079] (Production Example 1) <Preparation of Resin Mixture 1 Constituting Semiconductor Encapsulant Composition 1> 0.63 g of polymer 1, 3.14 g of biphenyl-type epoxy resin (YX4000H, manufactured by Mitsubishi Chemical), and 3.14 g of phenol novolac-type epoxy resin (Epiclon N-775, manufactured by DIC) were weighed out and kneaded in a mortar to obtain resin mixture 1. That is, the blending ratio of polymer 1 to epoxy resin in resin mixture 1 was the same as in the case of semiconductor encapsulant composition 1.

[0080] (Examples 2 to 22) <Preparation of Resin Mixtures 2 to 22 Constituting Semiconductor Encapsulant Compositions 2 to 22> Resin mixtures 2 to 22 were obtained in the same manner as in Preparation Example 1, except that the curing accelerator and silica were not included and the other components were mixed in the same ratio as in semiconductor encapsulant compositions 2 to 22.

[0081] (shear viscosity measurement) The shear viscosity (mPa·s) at 100°C of the resin mixtures 1 to 22 obtained as described above was measured using a rheometer (MCR302, manufactured by Anton Paar Japan Co., Ltd.). Jig used: Parallel plate (D-CP / PP7, manufactured by Anton Paar Japan Co., Ltd.) Rotation speed: Changed from 0.1 / S to 300 / S in 1 minute, and then measured at 300 / S for about 7 minutes. The value at which the shear viscosity became constant was taken as the measured value. Fluidity was evaluated as follows: a shear viscosity of 14 mPa·s or less was rated as ◎, a shear viscosity of more than 14 mPa·s but less than 23 mPa·s was rated as 〇, and a shear viscosity of 23 mPa·s or more was rated as ×.

[0082] [Rating 2] The thermal expansion properties and water resistance of the semiconductor encapsulant compositions 1 to 22 obtained in Examples 1 to 17 and Comparative Examples 1 to 5 were evaluated by the following methods. The results are shown in Tables 1 and 2.

[0083] (Evaluation of thermal expansion) The semiconductor encapsulant compositions 1 to 22 obtained as described above were heated on a hot plate heated to 110°C, spread on an aluminum pan heat-resistant to 400°C or higher, and the top surface was pressed into a flat plate to form a flat surface. The resulting pan was then cooled to room temperature to obtain semiconductor encapsulant test pieces. The flat surface of the test pieces thus obtained was heated from 30°C to 320°C (10°C / min) using a thermomechanical analyzer (Seiko Instruments Inc., EXSTAR6000) to measure the thermal expansion of each test piece. The magnitude of the slope of the temperature-TMA line (hereinafter simply referred to as the "TMA line") obtained under the heating conditions was used as an index of thermal expandability. A semiconductor encapsulant composition prepared without polymer or silicone was used as a blank, and the value calculated so that the slope of the blank TMA line was 100 was used as an evaluation value of thermal expandability. The thermal expansion property was evaluated as follows: a rating of 79 or less was ⊚; a rating of more than 79 but less than 101 was ◯; and a rating of 101 or more was x.

[0084] (Water resistance evaluation) The semiconductor encapsulant compositions 1 to 22 obtained as described above were heated on a hot plate heated to 110°C, filled into a mold having a cavity of 3 cm x 3 cm x 0.5 cm in length x width x thickness, and held for 180 minutes. The mold was then cooled and removed to obtain test pieces of the semiconductor encapsulant. The test pieces and 20 g of ion-exchanged water were placed in a 50 ml screw-cap test tube and shaken continuously for 6 hours in a water bath at 80°C. After that, water droplets adhering to the test pieces were wiped off, and the weights were measured. The mass change was calculated using the following formula. [Mass change (%)] = [Weight after test (g)] / [Weight before test (g)] x 100 The mass change was evaluated as follows: less than 1.0%: Excellent; 1.0% to less than 2.0%: Good; 2.0% or more: Bad.

[0085] (Evaluation of elution resistance) The electrical conductivity of the ion-exchanged water after the water resistance evaluation described above was measured using an electrical conductivity meter (tabletop electrical conductivity meter DS-72, manufactured by Horiba, Ltd.). Electrical conductivity is 1.1μS / m 2 Less than 1.1μS / cm 2 If it is more than 1.5 and less than 1.5, it is OK. 1.5μS / cm 2 If it was more than this, it was marked as ×.

[0086] [Table 1]

[0087] [Table 2]

[0088] As shown in Tables 1 and 2, the semiconductor encapsulant compositions of the examples, which contain components such as predetermined polymers within predetermined content ranges, can form semiconductor encapsulants that have excellent fluidity when heated, low thermal expansion, and excellent water resistance. Comparative Example 1 did not contain a polymer, and therefore the water resistance and resistance to elution were insufficient. In Comparative Example 2, the weight average molecular weight of the polymer was too high, and although the thermal expansion properties, water resistance, and elution resistance were excellent, the fluidity was significantly reduced. In Comparative Example 3, the polymer did not contain any structural units derived from the monomer (A), and therefore the fluidity and thermal expansion properties were low, and the water resistance and resistance to elution were also low. Comparative Example 4 contained silicone oil instead of the specified polymer, and therefore had excellent thermal expansion properties, but had low compatibility with resins, resulting in poor fluidity and resistance to elution. Comparative Example 5 contained a silicone resin instead of the specified polymer, and therefore exhibited excellent thermal expansion properties, and also had good water resistance and resistance to elution, but the fluidity was significantly reduced.

Claims

[Claim 1] A semiconductor encapsulant composition comprising, as structural units, 10 to 100 mol % of a monomer (A) represented by the following formula (1), and 0 to 90 mol % of a hydroxyl group-containing (meth)acrylate (B) represented by the following formula (2), in an amount of 0.1 to 5 mass % of a polymer having a weight average molecular weight of 3,000 to 100,000, 1 to 25 mass % of an epoxy resin, and 63 to 97 mass % of inorganic particles: 【Chemistry 1】 (In formula (1), R １ represents hydrogen or a methyl group, and R ２ represents —O— or —NH—.) CH ２ =CR ３ -COO-R ４ ・・・(2) (In formula (2), R ３ represents a hydrogen atom or a methyl group, and R ４ represents a hydroxyalkyl group having 1 to 4 carbon atoms.

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