Semiconductor encapsulant and semiconductor device

Abstract

To provide a semiconductor sealing resin composition that gives a cured product being low in dielectric constant and dielectric loss tangent and excellent in metal adhesion and moldability, a semiconductor sealing material composed of the composition, and a semiconductor device.SOLUTION: A semiconductor sealing material 6 is used to seal a semiconductor by the transfer molding or compression molding technique. The semiconductor sealant is in the form of a tablet or a crushed product. The semiconductor sealant is composed of a semiconductor sealing resin composition. The semiconductor sealing resin composition comprises an epoxy resin and an active ester resin.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a resin composition for semiconductor encapsulation and a semiconductor device. More specifically, the present invention relates to a resin composition used as a material for encapsulating semiconductor elements and a semiconductor device manufactured using the same.

Background Art

[0002] Epoxy resin, which is a type of thermosetting resin, is used in various fields such as electrical and electronic materials, paints, adhesives, and composite materials because its cured product has excellent properties such as heat resistance and electrical insulation. In particular, in the field of electrical and electronic materials, epoxy resin is used as a semiconductor encapsulant and a printed circuit board material.

[0003] In recent years, with the improvement in performance and miniaturization of electronic devices, the frequency of transmission signals has been increasing. Along with this increase in frequency, there is a strong demand for materials used in printed wiring boards and semiconductor encapsulants to have a lower dielectric constant in the high-frequency region. As materials capable of achieving these low dielectric constants and low dielectric tangents, a technique is known in which an active ester compound obtained by reacting a dicyclopentadiene-type phenol resin with benzoyl chloride and bis(chlorocarbonyl)benzene is used as a curing agent for epoxy resin (for example, Patent Document 1).

[0004] Patent Document 1 describes an epoxy resin composition using a specific active ester compound. Patent Document 1 describes that by using a specific active ester compound, a resin cured product having a lower dielectric constant and dielectric tangent can be obtained compared to the case of using a conventional curing agent such as a phenol novolac resin.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the epoxy resin composition described in Patent Document 1 does not satisfy the current dielectric properties, and is not sufficient in terms of adhesion to insert products such as metal lead frames of semiconductor elements to be encapsulated.

[0007] The present inventor has found that by blending an active ester resin having a specific structure into an epoxy resin composition, a cured product thereof has a low dielectric constant and a low dielectric loss tangent, is excellent in adhesion to insert products such as metal lead frames, and can be suitably used as a semiconductor encapsulating material, thereby completing the present invention.

Means for Solving the Problems

[0008] According to the present invention, a semiconductor encapsulant used for encapsulating a semiconductor by a transfer molding method or a compression molding method, wherein the semiconductor encapsulant is in the form of tablets or pulverized materials, the semiconductor encapsulant is composed of a resin composition for semiconductor encapsulation, the resin composition for semiconductor encapsulation contains an epoxy resin and an active ester resin, A curing accelerator, an inorganic filler, and and the inorganic filler is in an amount of 80% by mass or more and 96% by mass or less based on the total solid content of the resin composition for semiconductor encapsulation, the curing accelerator is in an amount of 1% by mass or more and 10% by mass or less based on the active ester resin, the active ester resin has an ester group equivalent of 200 g / eq or more, the blending amounts of the active ester resin and the epoxy resin are in a ratio such that the epoxy groups in the epoxy resin are 0.8 to 1.2 equivalents per 1 equivalent of the total active groups in the active ester resin, the active ester resin is provided in an amount of 1% by mass or more and 15% by mass or less based on the total solid content of the resin composition for semiconductor encapsulation.

[0009] Also according to the present invention, a substrate, a semiconductor element mounted on the substrate, and an encapsulant for encapsulating the semiconductor element, are provided. The encapsulant comprises a cured product of the above semiconductor encapsulation material to provide a semiconductor device.

Advantages of the Invention

[0010] According to the present invention, there are provided a resin composition for semiconductor encapsulation, in which the cured product has a low dielectric constant and dielectric loss tangent and excellent adhesion and moldability to metals, and a semiconductor device including the cured product of the resin composition as an encapsulant.

Brief Description of the Drawings

[0011]

Figure 1

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described. The resin composition of the present embodiment is a resin composition for use as an encapsulating material for encapsulating a semiconductor, and includes an epoxy resin and an active ester resin. In the present embodiment, the active ester resin is a resin having a structure represented by formula (1).

Chemical formula

Chemical formula

[0013] By including a specific active ester resin, the resin composition of the present embodiment has excellent dielectric properties and excellent adhesion to insert parts.

[0014] Further, the semiconductor device of the present embodiment is characterized in that a semiconductor element is encapsulated with a cured product of the above-described resin composition. Thereby, a semiconductor device excellent in reliability can be obtained.

[0015] As the epoxy resin used in the resin composition of the present embodiment, those generally used in epoxy resin compositions for semiconductor encapsulation can be used. Examples thereof include epoxy resins obtained by epoxidizing novolak resins obtained by condensing or co-condensing phenols such as phenol novolak type epoxy resins and orthocresol novolak type epoxy resins; phenols such as cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, etc. and / or naphthols such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc. with compounds having aldehyde groups such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, salicylaldehyde, etc. under an acidic catalyst; diglycidyl ethers such as bisphenol A, bisphenol F, bisphenol S, bisphenol A / D, etc.; biphenyl type epoxy resins which are diglycidyl ethers of alkyl-substituted or unsubstituted biphenols; epoxy compounds of phenol aralkyl resins synthesized from phenols and / or naphthols and dimethoxyparaxylene or bis(methoxymethyl)biphenyl; stilbene type epoxy resins, hydroquinone type epoxy resins, glycidyl ester type epoxy resins obtained by reacting polybasic acids such as phthalic acid, dimer acid, etc. with epichlorohydrin; glycidyl amine type epoxy resins obtained by reacting polyamines such as diaminodiphenylmethane, isocyanuric acid, etc. with epichlorohydrin; dicyclopentadiene type epoxy resins which are epoxy compounds of co-condensation resins of dicyclopentadiene and phenols; epoxy resins having a naphthalene ring; triphenol methane type epoxy resins; trimethylolpropane type epoxy resins; terpene-modified epoxy resins; linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid; alicyclic epoxy resins; and epoxy resins modified with silicone, acrylonitrile, butadiene, isoprene-based rubbers, polyamide-based resins, etc. These may be used alone or in combination of two or more kinds.

[0016] The active ester resin used in the resin composition of the present embodiment has an active ester group represented by the formula (B). In the curing reaction between the epoxy resin and the active ester resin, the active ester group of the active ester resin reacts with the epoxy group of the epoxy resin to generate a secondary hydroxyl group. This secondary hydroxyl group is blocked by the ester residue of the active ester resin. Therefore, the dielectric constant and the dielectric loss tangent of the cured product are reduced.

[0017] In one embodiment, the structure represented by the above formula (B) is preferably at least one selected from the following formulas (B-1) to (B-6).

Chemical formula

[0018] Since the structures represented by the above formulas (B-1) to (B-6) all have high orientation, when an active ester resin containing this is used, the cured product of the obtained resin composition has a low dielectric constant and a low dielectric loss tangent, and also has excellent adhesion to metals. Therefore, it can be preferably used as a semiconductor encapsulating material. Among them, from the viewpoints of low dielectric constant and low dielectric loss tangent, an active ester resin having a structure represented by the formula (B-3) or (B-5) is preferable, and further, an active ester resin having a structure in which X in the formula (B-3) is an ether bond, or a structure in which two carbonyloxy groups in the formula (B-5) are in the 4,4'-position is more preferable. Also, it is preferable that all of R 1 in each formula are hydrogen atoms.

[0019] "Ar'" in formula (1) is an aryl group and can be, for example, a phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 3,5-xylyl group, o-biphenyl group, m-biphenyl group, p-biphenyl group, 2-benzylphenyl group, 4-benzylphenyl group, 4-(α-cumyl)phenyl group, 1-naphthyl group, 2-naphthyl group, etc. Among them, particularly since a cured product having low dielectric constant and dielectric loss tangent can be obtained, it is preferably a 1-naphthyl group or a 2-naphthyl group.

[0020] In the present embodiment, "A" in the active ester resin represented by formula (1) is a substituted or unsubstituted arylene group linked via an aliphatic cyclic hydrocarbon group. Examples of such an arylene group include a structure obtained by a polyaddition reaction of an unsaturated aliphatic cyclic hydrocarbon compound containing two double bonds in one molecule and a phenolic compound.

[0021] Examples of the unsaturated aliphatic cyclic hydrocarbon compound containing two double bonds in one molecule include dicyclopentadiene, a multimer of cyclopentadiene, tetrahydroindene, 4-vinylcyclohexene, 5-vinyl-2-norbornene, limonene, etc. These may be used alone or in combination of two or more. Among these, dicyclopentadiene is preferred because a cured product having excellent heat resistance can be obtained. Since dicyclopentadiene is contained in petroleum fractions, industrial dicyclopentadiene may contain a multimer of cyclopentadiene and other aliphatic or aromatic diene compounds as impurities. However, considering properties such as heat resistance, curability, and moldability, it is desirable to use a product having a dicyclopentadiene purity of 90% by mass or more.

[0022] On the one hand, the phenolic compound may be, for example, phenol, cresol, xylenol, ethylphenol, isopropylphenol, butylphenol, octylphenol, nonylphenol, vinylphenol, isopropenylphenol, allylphenol, phenylphenol, benzylphenol, chlorophenol, bromophenol, 1-naphthol, 2-naphthol, 1,4-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, etc. Each of them may be used alone, or two or more of them may be used in combination. Among these, phenol is preferable because it becomes an active ester resin with high curability and excellent dielectric properties in the cured product.

[0023] In a preferred embodiment, "A" in the active ester resin represented by formula (1) has a structure represented by formula (A). A resin composition containing an active ester resin in which "A" in formula (1) has the following structure has a cured product with a low dielectric constant and a low dielectric tangent, and excellent adhesion to the insert article.

Chemical formula

[0024] Among the active ester resins represented by formula (1), particularly preferred are the resins represented by the following formula (1-1) and formula (1-2).

Chemical formula

Chemical formula

[0025] The active ester resin used in the present invention can be produced by a known method in which a phenolic compound (a) having a structure in which a plurality of aryl groups having phenolic hydroxyl groups are linked via an aliphatic cyclic hydrocarbon group, an aromatic nucleus-containing dicarboxylic acid or its halide (b), and an aromatic monohydroxy compound (c) are reacted.

[0026] The reaction ratios of the phenolic compound (a), the aromatic nucleus-containing dicarboxylic acid or its halide (b), and the aromatic monohydroxy compound (c) can be appropriately adjusted according to the desired molecular design. Among them, since a more highly curable active ester resin can be obtained, with respect to a total of 1 mol of the carboxyl groups or acid halide groups of the aromatic nucleus-containing dicarboxylic acid or its halide (b), the phenolic hydroxyl groups of the phenolic compound (a) are in the range of 0.25 to 0.90 mol, and it is preferable to use each raw material at a ratio such that the hydroxyl groups of the aromatic monohydroxy compound (c) are in the range of 0.10 to 0.75 mol. More preferably, the phenolic hydroxyl groups of the phenolic compound (a) are in the range of 0.50 to 0.75 mol, and the hydroxyl groups of the aromatic monohydroxy compound (c) are in the range of 0.25 to 0.50 mol.

[0027] In addition, when the functional group equivalent of the active ester resin is based on the total of the arylcarbonyloxy groups and phenolic hydroxyl groups in the resin structure as the number of functional groups of the resin, since a cured product with excellent curability and low dielectric constant and dielectric loss tangent can be obtained, it is preferably in the range of 200 g / eq or more and 230 g / eq or less, and more preferably in the range of 210 g / eq or more and 220 g / eq or less.

[0028] In the resin composition of the present embodiment, the blending amounts of the active ester resin and the epoxy resin are preferably at a ratio such that the epoxy groups in the epoxy resin are 0.8 to 1.2 equivalents with respect to a total of 1 equivalent of the active groups in the active ester resin, since a cured product with excellent curability and low dielectric constant and dielectric loss tangent can be obtained. Here, the active groups in the active ester resin refer to the arylcarbonyloxy groups and phenolic hydroxyl groups in the resin structure.

[0029] In addition, other thermosetting resins may be blended into the resin composition of the present embodiment as needed. Examples of other thermosetting resins that can be used here include cyanate ester compounds, vinyl benzyl compounds, acrylic compounds, maleimide compounds, copolymers of styrene and maleic anhydride, and the like. Among them, an acrylic compound is preferably used because the resulting resin composition has good fluidity. When using the above-mentioned other thermosetting resins, the amount used is not particularly limited as long as the effects of the present invention are not impaired, but it is preferably in the range of 1% by mass or more and 50% by mass or less based on the total solid content of the resin composition.

[0030] In the composition of the present embodiment, the active ester resin is used in an amount of 1% by mass or more and 15% by mass or less, preferably 3% by mass or more and 10% by mass or less based on the total solid content of the resin composition.

[0031] The resin composition of the present invention preferably contains a curing agent. Examples of the curing agent include amine compounds such as diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, imidazole, BF3-amine complex, and guanidine derivatives; amide compounds such as dicyandiamide and polyamide resins synthesized from dimers of linolenic acid and ethylenediamine; acid anhydrides such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride; polyhydric phenol compounds such as phenol novolac resin, cresol novolac resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin, dicyclopentadiene phenol addition type resin, phenol aralkyl resin, naphthol aralkyl resin, trimethylolmethane resin, tetraphenylol ethane resin, naphthol novolac resin, naphthol-phenol co-condensed novolac resin, naphthol-cresol co-condensed novolac resin, biphenyl-modified phenol resin (a polyhydric phenol compound in which phenol nuclei are linked by bismethylene groups), biphenyl-modified naphthol resin (a polyhydric naphthol compound in which phenol nuclei are linked by bismethylene groups), and aminotriazine-modified phenol resin (a polyhydric phenol compound in which phenol nuclei are linked by melamine or benzoguanamine).

[0032] When using a curing agent, its blending amount is preferably in an amount of 1% by mass or more and 40% by mass or less with respect to the active ester resin. The lower limit value of the blending amount of the curing agent with respect to the active ester resin can be, for example, 1% by mass or more, 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, or 30% by mass or more, and the upper limit value can be 40% by mass or less, 35% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less. By using the curing agent in the amount within the above range, a resin composition having excellent curability can be obtained.

[0033] In one embodiment, an inorganic filler is compounded into the resin composition to reduce moisture absorption, reduce the coefficient of linear expansion, improve thermal conductivity, and improve strength. Examples of the inorganic filler include powders such as fused silica, crystalline silica, alumina, calcium silicate, calcium carbonate, potassium titanate, silicon carbide, silicon nitride, aluminum nitride, boron nitride, beryllia, zirconia, zircon, forsterite, steatite, spinel, mullite, titania, etc., or beads obtained by spheroidizing these, glass fibers, and the like. These inorganic fillers may be used alone or in combination of two or more. Among the above inorganic fillers, fused silica is preferable from the viewpoint of reducing the coefficient of linear expansion, and alumina is preferable from the viewpoint of high thermal conductivity. The shape of the filler is preferably spherical from the viewpoints of fluidity during molding and mold wear.

[0034] From the viewpoints of moldability, reduction of thermal expansibility, and improvement of strength, the compounding amount of the inorganic filler is preferably in the range of 80% by mass or more and 96% by mass or less, more preferably in the range of 82% by mass or more and 92% by mass or less, and even more preferably in the range of 86% by mass or more and 90% by mass or less with respect to the total solid content of the resin composition. If it is less than the lower limit value, the effect of reducing thermal expansibility may not be obtained, and if it exceeds the upper limit value, the moldability may decrease.

[0035] In addition to the above components, the resin composition of the present embodiment may contain various components such as a silane coupling agent, a release agent, and a pigment, if necessary.

[0036] The resin composition of the present embodiment can be produced by uniformly mixing the above-mentioned respective components. Examples of the production method include a method in which raw materials in a predetermined compounding amount are sufficiently mixed by a mixer or the like, then melt-kneaded by a mixing roll, a kneader, an extruder, etc., and then cooled and pulverized. The obtained resin composition may be tableted with dimensions and mass suitable for molding conditions, if necessary.

[0037] Alternatively, the resin composition of the present embodiment can be dissolved in an organic solvent and used as a liquid encapsulating material. In this case, it can also be used as a sheet or film-like material obtained by thinly applying the liquid resin composition on a plate or film and dispersing the organic solvent under conditions where the curing reaction of the resin does not proceed much.

[0038] Next, the semiconductor device of the present embodiment will be described. The semiconductor device of the present embodiment is obtained by encapsulating a semiconductor element with the above-described resin composition. Examples of such a semiconductor device include those in which elements such as semiconductor chips, active elements such as transistors, diodes, and thyristors, and passive elements such as capacitors, resistors, and coils are mounted on a support member of a copper lead frame, and the necessary parts are encapsulated with the epoxy resin composition for semiconductor encapsulation of the present invention. Further, examples of such a semiconductor device include, for example, a semiconductor element fixed on a copper lead frame, the terminals and leads of the elements such as bonding pads are connected by wire bonding or bumps, and then encapsulated by transfer molding or the like using the epoxy resin composition for semiconductor encapsulation of the present invention, general resin-encapsulated ICs such as DIP (Dual Inline Package), PLCC (Plastic Leaded Chip Carrier), QFP (Quad Flat Package), SOP (Small Outline Package), SOJ (Small Outlaine J-lead package), TSOP (Thin Small Outline Package), and TQFP (Thin Quad Flat Package). Also included are semiconductor packages in which semiconductor chips such as MCP (Multi Chip Stacked Package) are stacked in multiple layers.

[0039] FIG. 1 is a cross-sectional view showing an example of a semiconductor device using the resin composition for semiconductor encapsulation according to the present invention. In FIG. 1, semiconductor elements 1 are laminated and fixed in two stages on a die pad 3 via a cured die bonding material 2. The electrode pads of the semiconductor element 1 and the lead frame 5 are connected by a gold wire 4. The semiconductor element 1 is encapsulated with an encapsulant 6 made of a cured product of the above-described resin composition for encapsulation. Since the semiconductor element 1 is encapsulated with a cured product of the above-described resin composition having excellent dielectric properties and excellent adhesion to insert products, a semiconductor device with excellent reliability can be obtained.

[0040] As a method for encapsulating an element using the resin composition for semiconductor encapsulation of the present invention, the low-pressure transfer molding method is the most common, but an injection molding method, a compression molding method, etc. may also be used. When the resin composition for semiconductor encapsulation is liquid or paste-like at room temperature, a dispensing method, a casting method, a printing method, etc. can be mentioned.

[0041] In addition, there is also a hollow package method in which the element is not in direct contact with the resin composition for semiconductor encapsulation, not just a general encapsulation method of directly resin-encapsulating the element, and it can also be suitably used as the resin composition for semiconductor encapsulation for a hollow package.

[0042] As described above, the embodiments of the present invention have been described, but these are examples of the present invention, and various configurations other than the above can be adopted.

Examples

[0043] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

[0044] (Example 1) (Preparation of active ester resin (1)) Into a flask equipped with a thermometer, a dropping funnel, a condenser, a fractionating column, and a stirrer, 279.1 g (number of moles of acid chloride groups: 2.0 moles) of biphenyl-4,4'-dicarboxylic acid dichloride and 1338 g of toluene were charged, and the system was purged with nitrogen under reduced pressure and dissolved. Next, 96.5 g (0.67 mole) of α-naphthol and 219.5 g of dicyclopentadiene phenol resin (number of moles of phenolic hydroxyl groups: 1.33 moles) were charged, and the system was purged with nitrogen under reduced pressure and dissolved. Then, while purging with nitrogen gas, the temperature inside the system was controlled to 60 °C or lower, and 400 g of a 20% aqueous sodium hydroxide solution was added dropwise over 3 hours. Subsequently, stirring was continued for 1.0 hour under these conditions. After completion of the reaction, the mixture was allowed to stand and separated, and the aqueous layer was removed. Further, water was added to the toluene phase in which the reaction product was dissolved, and the mixture was stirred and mixed for about 15 minutes, allowed to stand and separated, and the aqueous layer was removed. This operation was repeated until the pH of the aqueous layer reached 7. Thereafter, water was removed by decanter dehydration to obtain an active ester resin (1) in the form of a toluene solution having a non-volatile content of 65%. The solution viscosity of this toluene solution having a non-volatile content of 65% by mass was 5540 mPa·S (25 °C). Also, the softening point of the solid content of the active ester resin obtained by drying this was 138 °C.

[0045] (Preparation and Physical Property Evaluation of Resin Composition) According to the formulation shown in Table 1 below, as an epoxy resin, HP-7200H manufactured by DIC (dicyclopentadiene phenol type epoxy resin, melt viscosity at 150 °C: 0.30 poise, epoxy group equivalent: 277 g / equivalent) was blended, and as a curing agent, the active ester resin (1) obtained above was blended. Further, an amount of 0.5 phr of dimethylaminopyridine was added as a curing catalyst, and finally, methyl ethyl ketone was blended and adjusted so that the non-volatile content (N.V.) of each composition was 58% by mass. The spiral flow of the obtained resin composition was prepared by the following method. (Measurement of Spiral Flow) Using a mold for measuring spiral flow according to EMMI-I-66, the measurement was carried out at a mold temperature of 175 °C, an injection pressure of 6.8 MPa, and a curing time of 2 minutes, and the result was 120 cm. (Measurement of Dielectric Properties) Next, the obtained resin composition was molded at a mold temperature of 175°C, an injection pressure of 10 MPa, and a curing time of 2 minutes to produce a disk with a diameter of 50 mm and a thickness of 3 mm. Regarding the obtained cured product, in accordance with JIS-C-6481, the dielectric constant and dielectric tangent at 1 GHz of the test piece after being stored in a room at 23°C and 50% humidity for 24 hours after absolute drying were measured using the impedance material analyzer "HP4291B" manufactured by Agilent Technologies Co., Ltd. The results are shown in Table 1.

[0046] (Fabrication and Physical Property Evaluation of Semiconductor Devices) The adhesion to each metal (Ag, Cu, Ni) was evaluated by the following method. The resin composition obtained above was molded on substrates made of various metals (silver, copper, nickel) under the conditions of 175°C, 6.9 MPa, and 2 minutes, and post-cured for 4 hours. Then, the shear adhesion to each substrate was measured at room temperature. The results are shown in Table 1.

[0047]

Table 1

[0048] The cured product of the resin composition of Example 1 had excellent dielectric properties and excellent adhesion to the above metals. Therefore, it can be suitably used as a material for encapsulating semiconductor elements provided with lead frames and the like.

Explanation of Reference Numerals

[0049] 1 Semiconductor element 2 Cured die bonding material 3 Die pad 4 Gold wire 5 Lead frame 6 Encapsulant (cured product of encapsulating resin composition)

Claims

1. A semiconductor encapsulant used for encapsulating a semiconductor by a transfer molding method or a compression molding method, wherein the semiconductor encapsulant is in the form of tablets or pulverized materials, the semiconductor encapsulant is composed of a resin composition for semiconductor encapsulation, the resin composition for semiconductor encapsulation contains an epoxy resin, an active ester resin, a curing accelerator, and an inorganic filler, the inorganic filler is in an amount of 80% by mass or more and 96% by mass or less based on the total solid content of the resin composition for semiconductor encapsulation, the curing accelerator is in an amount of 1% by mass or more and 10% by mass or less based on the active ester resin, the active ester resin has an ester group equivalent of 200 g / eq or more, the blending amount of the active ester resin and the epoxy resin is such that the epoxy groups in the epoxy resin are 0.8 to 1.2 equivalents with respect to a total of 1 equivalent of the active groups in the active ester resin, the active ester resin is in an amount of 1% by mass or more and 15% by mass or less based on the total solid content of the resin composition for semiconductor encapsulation, a semiconductor encapsulant.

2. The semiconductor encapsulant according to claim 1, wherein the active ester resin has an ester group equivalent of 200 g / eq or more and 230 g / eq or less.

3. a substrate, a semiconductor element mounted on the substrate, and an encapsulant for encapsulating the semiconductor element, wherein the encapsulant is composed of a cured product of the semiconductor encapsulant according to claim 1 or 2, a semiconductor device.

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