Sealing composition and semiconductor device

Abstract

To provide a sealing composition that strikes a balance between flowability and heat dissipation, and an electronic component device having an element sealed therewith.SOLUTION: A sealing composition contains an epoxy resin, a curing agent, and an inorganic filler containing alumina. The inorganic filler accounts for 80 vol.% or more of the total nonvolatile content, and at least one of the epoxy resin and the curing agent has a melt viscosity of 120 mPa s or more.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an encapsulating composition and a semiconductor device.

[0002] In recent years, thin electronic devices such as smartphones have become smaller, lighter, and more functional. As a result, the amount of heat generated by electronic devices that handle large amounts of information at high speeds has increased, which can cause the electronic devices to malfunction. Therefore, there is a demand for efficient dissipation of heat generated inside the devices.

[0003] While structures that can easily dissipate heat have been developed to improve the heat dissipation of electronic devices, there is also a need to improve the heat dissipation properties of the encapsulants used in the electronic components built in. For example, mixing inorganic fillers into the encapsulants or increasing the amount of inorganic fillers mixed in have been considered. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4188634 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, there is a trade-off between the amount of inorganic filler contained in the encapsulant and the fluidity of the encapsulant. In other words, increasing the amount of inorganic filler improves heat dissipation, but decreases the fluidity of the encapsulant, which may result in insufficient reliability of electronic components. This tendency is particularly pronounced when alumina is used as the inorganic filler. Therefore, there is a need for a method for improving the heat dissipation of epoxy resin compositions other than increasing the amount of inorganic filler.

[0006] In view of the above circumstances, an object of the present invention is to provide an encapsulating composition that has an excellent balance between flowability and heat dissipation properties, and an electronic component device including an element encapsulated with the encapsulating composition. [Means for solving the problem]

[0007] Specific means for achieving the above object are as follows. <1> An encapsulating composition comprising an epoxy resin, a curing agent, and an inorganic filler containing alumina, wherein the content of the inorganic filler is 80 volume% or more of the total non-volatile matter, and at least one of the epoxy resin and the curing agent has a melt viscosity of 120 mPa s or more. <2> A semiconductor element and a package formed by sealing the semiconductor element. <1> A semiconductor device comprising a cured product of the sealing composition according to claim 1. Effect of the Invention

[0008] According to the present invention, it is possible to provide an encapsulating composition having an excellent balance between flowability and heat dissipation properties, and an electronic component device including an element encapsulated with the encapsulating composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiment for carrying out the encapsulating composition and semiconductor device of the present invention will be described in detail. However, the present invention is not limited to the following embodiment. In the following embodiment, the components (including element steps, etc.) are not essential unless specifically stated. The same applies to the numerical values ​​and their ranges, and do not limit the present invention. In the present disclosure, a numerical range indicated using "~" includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in the present disclosure in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples. In the present disclosure, each component may contain multiple types of the corresponding substance. When multiple substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified.

[0010] <Sealing composition> The sealing composition of the present disclosure contains an epoxy resin, a curing agent, and an inorganic filler containing alumina, wherein the content of the inorganic filler is 80 volume % or more of the total non-volatile content, and at least one of the epoxy resin and the curing agent has a melt viscosity of 120 mPa s or more.

[0011] It was found that the sealing composition having the above-mentioned structure has improved heat dissipation properties without further increasing the amount of inorganic filler. The reason for this is not entirely clear, but it is thought that when the sealing composition is made to flow, the inorganic filler exhibits flow behavior similar to that of other components because the melt viscosity of at least one of the epoxy resin and the curing agent is 120 mPa s or more. As a result, it is presumed that this is because uneven distribution of the inorganic filler after curing is suppressed.

[0012] The epoxy resin or curing agent contained in the encapsulating composition may be one kind or a combination of two or more kinds. When the epoxy resin or curing agent is a combination of two or more kinds, the melt viscosity is the melt viscosity of the entire combination of two or more kinds. The melt viscosity of the epoxy resin or hardener is measured by setting the cone at the measurement temperature using a cone-plate viscometer conforming to JIS K 7234:1986 and JIS K 7233:1986. The measurement temperature shall be the temperature stated in each purchase specification.

[0013] From the viewpoint of improving heat dissipation, the melt viscosity of at least one of the epoxy resin and the curing agent is 120 mPa·s or more, preferably 140 mPa·s or more, and more preferably 160 mPa·s or more. From the viewpoint of ensuring sufficient fluidity, the melt viscosity of at least one of the epoxy resin and the curing agent is preferably 300 mPa·s or less, more preferably 240 mPa·s or less, and even more preferably 200 mPa·s or less.

[0014] Each component constituting the sealing composition will be described below. The sealing composition of the present disclosure contains an epoxy resin, a curing agent, and an inorganic filler containing alumina, and may contain other components as necessary.

[0015] -Epoxy resin- The sealing composition contains an epoxy resin. The type of the epoxy resin is not particularly limited, and any known epoxy resin can be used. Specifically, for example, novolak resins obtained by condensing or co-condensing at least one selected from the group consisting of phenolic compounds (e.g., phenol, cresol, xylenol, resorcin, catechol, bisphenol A, and bisphenol F) and naphthol compounds (e.g., α-naphthol, β-naphthol, and dihydroxynaphthalene) with an aldehyde compound (e.g., formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and salicylaldehyde) under an acidic catalyst are epoxidized (e.g., phenol novolak type epoxy resins and orthocresol novolak type epoxy resins); bisphenols (e.g., bisphenol A, bisphenol AD, bisphenol F, and bisphenol S) ) and biphenols (e.g., alkyl-substituted and unsubstituted biphenols); epoxidized products of phenol-aralkyl resins; epoxidized products of adducts or polyadditions of phenolic compounds with at least one selected from the group consisting of dicyclopentadiene and terpene compounds; glycidyl ester type epoxy resins obtained by reacting polybasic acids (e.g., phthalic acid and dimer acid) with epichlorohydrin; glycidylamine type epoxy resins obtained by reacting polyamines (e.g., diaminodiphenylmethane and isocyanuric acid) with epichlorohydrin; linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids (e.g., peracetic acid); and alicyclic epoxy resins. The epoxy resins may be used alone or in combination of two or more.

[0016] - Hardener - The sealing composition contains a curing agent. The type of the curing agent is not particularly limited, and any known curing agent can be used. Specifically, for example, novolak resins obtained by condensing or co-condensing at least one selected from the group consisting of phenolic compounds (e.g., phenol, cresol, resorcin, catechol, bisphenol A, and bisphenol F) and naphthol compounds (e.g., α-naphthol, β-naphthol, and dihydroxynaphthalene) with an aldehyde compound (e.g., formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and salicylaldehyde) under an acid catalyst; phenol-aralkyl resins; and naphthol-aralkyl resins; may be mentioned. The curing agent may be used alone or in combination of two or more kinds. Among them, the curing agent is preferably a phenol-aralkyl resin from the viewpoint of improving reflow resistance. The curing agent may be used alone or in combination of two or more kinds.

[0017] The amount of the curing agent is preferably set so that the equivalent of the functional group of the curing agent (for example, a phenolic hydroxyl group in the case of a novolac resin) is 0.5 to 1.5 equivalents per equivalent of the epoxy group of the epoxy resin, and more preferably set so that the equivalent is 0.7 to 1.2 equivalents.

[0018] -Inorganic filler- The sealing composition contains an inorganic filler containing alumina. When the sealing composition contains an inorganic filler, the moisture absorption of the sealing composition is reduced and the strength of the sealing composition in a cured state tends to be improved. In addition, when the inorganic filler contains alumina, the heat dissipation of the sealing composition tends to be further improved.

[0019] The inorganic filler may be used alone or in combination of two or more. When two or more inorganic fillers are used in combination, for example, two or more inorganic fillers having different components, average particle sizes, shapes, etc. may be used. The shape of the inorganic filler is not particularly limited, and examples thereof include powder, spheres, fibers, etc. From the viewpoints of flowability during molding of the sealing composition and mold abrasion, a spherical shape is preferred.

[0020] The inorganic filler may contain alumina, and may be entirely alumina or may be a combination of alumina and other inorganic fillers. Examples of other inorganic fillers that can be used in combination with alumina include silica such as spherical silica and crystalline silica, zircon, magnesium oxide, calcium silicate, calcium carbonate, potassium titanate, silicon carbide, silicon nitride, boron nitride, beryllia, and zirconia. Examples of inorganic fillers that have a flame retardant effect include aluminum hydroxide and zinc borate.

[0021] When alumina is used in combination with other inorganic fillers as the inorganic filler, the proportion of alumina in the entire inorganic filler is preferably 50 volume % or more, more preferably 70 volume % or more, and even more preferably 80 volume % or more.

[0022] The content of the inorganic filler in the sealing composition is not particularly limited as long as it is 80% by volume or more of the total non-volatile content, and can be set according to the desired properties, etc. From the viewpoint of ensuring flowability, it is preferably 95% by volume or less of the total non-volatile content, and more preferably 90% by volume or less.

[0023] (Cure accelerator) The sealing composition may further contain a curing accelerator. The type of the curing accelerator is not particularly limited, and any known curing accelerator may be used. Specifically, cycloamidine compounds such as 1,8-diaza-bicyclo[5.4.0]undecene-7, 1,5-diaza-bicyclo[4.3.0]nonene, and 5,6-dibutylamino-1,8-diaza-bicyclo[5.4.0]undecene-7, cycloamidine compounds with maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, and 2,3-dimethoxy-5-methyl-1,4-benzoquinone, quinone compounds such as 2,3-dimethoxy-1,4-benzoquinone and phenyl-1,4-benzoquinone; compounds with intramolecular polarization formed by adding compounds with π bonds such as diazophenylmethane and phenol resin; tertiary amine compounds such as benzyldimethylamine, triethanolamine, dimethylaminoethanol and tris(dimethylaminomethyl)phenol; derivatives of tertiary amine compounds; 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methyl-2-phenyl-2-phenyl-1,4 ... Examples of the curing accelerator include imidazole compounds such as thiimidazole, derivatives of imidazole compounds, organic phosphine compounds such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, tris(4-methylphenyl)phosphine, diphenylphosphine, and phenylphosphine, phosphorus compounds having intramolecular polarization obtained by adding compounds having π bonds such as maleic anhydride, the above-mentioned quinone compounds, diazophenylmethane, and phenolic resins to organic phosphine compounds, tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, 2-ethyl-4-methylimidazole tetraphenylborate, and N-methylmorpholine tetraphenylborate, and other tetraphenylborate salts, derivatives of tetraphenylborate salts, and adducts of phosphine compounds and tetraphenylborate salts such as triphenylphosphonium-triphenylborane and N-methylmorpholine tetraphenylphosphonium-tetraphenylborate. One type of curing accelerator may be used alone, or two or more types may be used in combination.

[0024] The content of the curing accelerator is preferably 0.1% by mass to 8% by mass based on the total amount of the epoxy resin and the curing agent.

[0025] (Ion trapping agent) The encapsulating composition may further contain an ion trapping agent. The ion trapping agent that can be used in the present disclosure is not particularly limited as long as it is an ion trapping agent generally used in encapsulating materials for semiconductor device manufacturing applications. Examples of the ion trapping agent include compounds represented by the following general formula (II-1) or the following general formula (II-2).

[0026] Mg 1-a Al a (OH)2(CO3) a / 2 ·uH2O (II-1) (In general formula (II-1), a satisfies 0 < a ≤ 0.5, and u is a positive number.) BiO b (OH) c (NO3) d (II-2) (In general formula (II-2), b satisfies 0.9 ≤ b ≤ 1.1, c satisfies 0.6 ≤ c ≤ 0.8, and d satisfies 0.2 ≤ d ≤ 0.4.)

[0027] The ion trapping agent is commercially available. As the compound represented by general formula (II-1), for example, "DHT-4A" (trade name, Kyowa Chemical Industry Co., Ltd.) is commercially available. Also, as the compound represented by general formula (II-2), for example, "IXE500" (trade name, Toagosei Co., Ltd.) is commercially available.

[0028] In addition, examples of ion trapping agents other than the above include hydrated oxides of elements selected from magnesium, aluminum, titanium, zirconium, antimony, etc. The ion trapping agent may be used alone or in combination of two or more.

[0029] When the sealing composition contains an ion trapping agent, the content of the ion trapping agent is preferably 1 part by mass or more per 100 parts by mass of the total amount of the epoxy resin and the curing agent from the viewpoint of realizing sufficient moisture resistance reliability, and is preferably 15 parts by mass or less per 100 parts by mass of the total amount of the epoxy resin and the curing agent from the viewpoint of fully exerting the effects of the other components.

[0030] (Coupling Agent) The sealing composition may further contain a coupling agent. The type of the coupling agent is not particularly limited, and a known coupling agent can be used. Examples of the coupling agent include a silane coupling agent and a titanium coupling agent. The coupling agent may be used alone or in combination of two or more types.

[0031] Examples of the silane coupling agent include vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-[bis(β-hydroxyethyl)]aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethoxysilane, Examples of the silane include trimethoxysilane, γ-(β-aminoethyl)aminopropyldimethoxymethylsilane, N-(trimethoxysilylpropyl)ethylenediamine, N-(dimethoxymethylsilylisopropyl)ethylenediamine, methyltrimethoxysilane, methyltriethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, γ-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, and γ-mercaptopropylmethyldimethoxysilane.

[0032] Examples of titanium coupling agents include isopropyl triisostearoyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl phosphite) titanate, bis(dioctyl pyrophosphate)oxyacetate titanate, bis(dioctyl pyrophosphate)ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl tridodecyl benzenesulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, and tetraisopropyl bis(dioctyl phosphite) titanate.

[0033] When the sealing composition contains a coupling agent, the content of the coupling agent is preferably 3% by mass or less based on the total amount of the sealing composition, and from the viewpoint of exerting its effect, it is preferably 0.1% by mass or more.

[0034] (Release agent) The encapsulating composition may further contain a release agent. The type of the release agent is not particularly limited, and a known release agent can be used. Specific examples include higher fatty acids, higher fatty acid esters, carnauba wax, and polyethylene wax. The release agent may be used alone or in combination of two or more types. When the encapsulating composition contains a release agent, the content of the release agent is preferably 10% by mass or less based on the total amount of the epoxy resin and the curing agent, and from the viewpoint of exerting its effect, it is preferably 0.5% by mass or more.

[0035] (Colorants and modifiers) The sealing composition may contain a colorant (e.g., carbon black). The sealing composition may also contain a modifier (e.g., silicone and silicone rubber). The colorant and modifier may each be used alone or in combination of two or more kinds.

[0036] When conductive particles such as carbon black are used as the colorant, the conductive particles preferably contain particles having a particle diameter of 10 μm or more in an amount of 1 mass % or less. When the sealing composition contains conductive particles, the content of the conductive particles is preferably 4 mass % or less based on the total amount of the epoxy resin and the curing agent.

[0037] <Method of producing sealing composition> The method for producing the encapsulating composition is not particularly limited, and can be performed by a known method. For example, the encapsulating composition can be produced by thoroughly mixing a mixture of raw materials in a predetermined amount using a mixer or the like, kneading the mixture using a hot roll, an extruder, or the like, and then cooling, pulverizing, or the like. The state of the encapsulating composition is not particularly limited, and may be in a powder, solid, liquid, or the like.

[0038] <Semiconductor device> The semiconductor device of the present disclosure includes a semiconductor element and a cured product of the sealing composition of the present disclosure that seals the semiconductor element.

[0039] The method for encapsulating a semiconductor element using the encapsulating composition is not particularly limited, and any known method can be applied. For example, a transfer molding method is generally used, but a compression molding method, an injection molding method, a compression molding method, etc. may also be used. EXAMPLES

[0040] Examples of the present invention will be described below, but the present invention is not limited thereto. Furthermore, the numerical values ​​in the tables mean "parts by mass" unless otherwise specified.

[0041] The materials shown in Table 1 were premixed (dry blended), then kneaded for about 15 minutes with a biaxial roll (roll surface temperature: about 80° C.), cooled, and pulverized to produce a powdered encapsulating composition. In Table 1, "-" indicates that the corresponding component is not included.

[0042] Details of the materials shown in Table 1 are as follows. Epoxy resin 1: Biphenyl type epoxy resin with an epoxy equivalent of 192g / eq, Mitsubishi Chemical Corporation, product name "YX4000H" Hardener 1: Aralkyl-type phenolic resin with a hydroxyl equivalent of 104 g / eq, Air Water Inc., product name "HE910-20" Hardener 2: Aralkyl-type phenolic resin with a hydroxyl equivalent of 104 g / eq, Air Water Inc., product name "HE910-09" Curing accelerator: Phosphorus-based curing accelerator Coupling agent: 3-glycidoxypropyltrimethoxysilane Release agent: Montan acid ester Colorant: Carbon black, Mitsubishi Chemical Corporation, product name "MA600" Modifier: Organofunctional siloxane, Toray Dow Corning, product name "BY16-876" Alumina 1: Alumina particles with a volume average particle size of 0.3 μm Alumina 2: Alumina particles with a volume average particle size of 21 μm Silica 1: Fused silica particles with a volume average particle size of 15 nm

[0043] <Melt Viscosity Measurement> The melt viscosity of the curing agent used was measured with a cone-plate viscometer in accordance with JIS K 7234:1986 and JIS K 7233:1986. The measurement temperature was 150° C. The results are shown in Table 1.

[0044] <Measurement of thermal conductivity> Using the encapsulating composition obtained above, a semiconductor element was encapsulated in a compression molding machine under the conditions of a mold temperature of 175°C to 180°C, a molding pressure of 7 MPa, and a curing time of 150 seconds to prepare a test piece for evaluating thermal conductivity. The thermal conductivity of the test piece was then measured by a xenon flash (Xe-flash) method. The results are shown in Table 1.

[0045] <Liquidity evaluation> Using a spiral flow measurement mold conforming to EMMI-1-66, the flow distance was measured when the encapsulating composition was molded with a transfer molding machine under the conditions of a mold temperature of 180°C, a molding pressure of 22.5 MPa, and a curing time of 300 seconds. The results are shown in Table 1.

[0046] <Hardness evaluation> Using a burr measurement mold conforming to EMMI-1-66, the prepared encapsulating composition was molded by a transfer molding machine under the conditions of a mold temperature of 180°C, molding pressure of 22.5 MPa, and curing time of 300 seconds, and then the mold was quickly removed, and the needle of a Shore hardness tester was pressed against the central cull 10±1 seconds after the mold opening started to measure the hardness. The results are shown in Table 1.

[0047] [Table 1]

[0048] As shown in Table 1, comparing Example 1, in which the proportion of inorganic filler is 82 volume % and the melt viscosity of the curing agent is 180 mPa s, with Comparative Example 1, which is the same as Example 1 except that the melt viscosity of the curing agent is 90 mPa s, it can be evaluated that Example 1 has a higher thermal conductivity of the cured product and is more excellent in heat dissipation. The fluidity (flow distance) of Example 1 is slightly lower than that of Comparative Example 1, but can be evaluated to be substantially the same.

Claims

1. 1. An encapsulating composition comprising an epoxy resin, a curing agent, and an inorganic filler containing alumina, wherein a content of the inorganic filler is 80 volume% or more of a total non-volatile content, and at least one of the epoxy resin and the curing agent has a melt viscosity of 120 mPa s or more.

2. A semiconductor device comprising a semiconductor element and a cured product of the encapsulating composition according to claim 1 encapsulating the semiconductor element.

Images