Sealing material and semiconductor device

Abstract

This sealing material contains an epoxy resin, an inorganic filler, and carbon black having a density of 1.82 g / cm3 or more.

Description

Encapsulating materials and semiconductor devices

[0001] This disclosure relates to encapsulating materials and semiconductor devices.

[0002] Epoxy resin encapsulants are widely used in the field of encapsulating electronic components such as transistors and ICs. This is because epoxy resins offer a good balance of electrical properties, moisture resistance, heat resistance, mechanical properties, and adhesion to insert components.

[0003] In recent years, with the miniaturization, weight reduction, and increased performance of electronic devices, the density of components has increased, leading to a significant increase in heat generation from electronic components. Furthermore, the number of electronic components operating at high temperatures has also increased.

[0004] In particular, power semiconductors for automotive applications are expected to be exposed to high temperatures for extended periods. From the viewpoint of improving mass production efficiency, vibration resistance, and heat resistance, epoxy resin encapsulation is increasingly being used in automotive power modules (see, for example, Patent Documents 1 and 2).

[0005] Japanese Patent Publication No. 2014-118433 Japanese Patent Publication No. 2022-098698

[0006] The surface of a semiconductor package sealed with epoxy resin is printed with various identification information, such as the manufacturing lot number and logo. Laser marking, which involves engraving the package surface with a laser, is sometimes used as the printing method. Laser marking eliminates the need for additional processes such as cleaning, offers higher production efficiency than ink-based printing, and improves the durability of the markings.

[0007] When applying laser marking, which offers excellent printability, encapsulants containing carbon black are used. However, because carbon black is conductive, its presence can lower the dielectric breakdown value of the encapsulant, potentially causing a short circuit. Short circuits are particularly likely to occur in applications where high voltages are applied, such as power semiconductor modules.

[0008] This disclosure is made in view of the above circumstances and aims to provide a sealing material that can suppress a decrease in dielectric breakdown value while maintaining laser marking properties when a sealing portion is formed, and a semiconductor device sealed using the same.

[0009] This disclosure includes the following aspects: <1> an epoxy resin, an inorganic filler, and a material with a density of 1.82 g / cm³ ３ An encapsulant containing the above carbon black. <2> The encapsulant according to <1>, wherein the volatile content of the carbon black is 1.0% by mass or less. <3> The encapsulant according to <1> or <2>, wherein the ash content of the carbon black is 0.15% by mass or less. <4> The encapsulant according to any one of <1> to <3>, wherein the chloride ion content of the carbon black is 15 ppm by mass or less. <5> The encapsulant according to any one of <1> to <4>, wherein the sulfur content of the carbon black is 0.1% by mass or less. <6> The encapsulant according to any one of <1> to <5>, wherein the sodium ion content of the carbon black is 20 ppm by mass or less. <7> The encapsulant according to any one of <1> to <6>, wherein the potassium ion content of the carbon black is 15 ppm by mass or less. <8> The encapsulant according to any one of <1> to <7>, wherein the average particle size of the carbon black is 10 nm or more. <9> A sealing material according to any one of <1> to <8> for sealing power semiconductors. <10> A semiconductor device comprising: a semiconductor chip; a lead frame on which the semiconductor chip is mounted; and a cured product of the sealing material according to any one of <1> to <9> for sealing the semiconductor chip.

[0010] According to this disclosure, it is possible to provide a sealing material that can suppress a decrease in dielectric breakdown value while maintaining laser marking properties when a sealing portion is formed, and a semiconductor device sealed using the same.

[0011] This is a schematic cross-sectional view showing an example of the configuration of a semiconductor device in this disclosure.

[0012] The following describes in detail the forms for implementing this disclosure. However, this disclosure is not limited to the following embodiments. In the following embodiments, the components (including elemental steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and they do not limit this disclosure. In numerical ranges indicated using "~" in this disclosure, the numerical values ​​before and after "~" are included as the minimum and maximum values, respectively. In numerical ranges described in stages in this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Also, in numerical ranges described in this disclosure, the upper or lower limit of that numerical range may be replaced with the value shown in the example. In this disclosure, each component may contain multiple types of the corresponding substance. If multiple types of the substance 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 types of substances present in the composition unless otherwise specified. In this disclosure, each component may contain multiple types of particles. If multiple types of particles corresponding to each component are present in the composition, the particle size of each component refers to the value for a mixture of those multiple types of particles present in the composition, unless otherwise specified.

[0013] When embodiments of this disclosure are described with reference to the drawings, the configuration of such embodiments is not limited to the configuration shown in the drawings. Furthermore, the sizes of the members in each drawing are conceptual, and the relative relationships of the sizes of the members are not limited thereto. In addition, in each drawing, members having substantially the same function are given the same reference numeral in all drawings, and redundant descriptions are omitted. In this disclosure, the up and down direction is not limited to the vertical up and down direction, and may be reversed. Also, the up and down direction may be replaced with the left and right direction. In this disclosure, the term "layer" includes cases where the layer is formed in the entire region when the region in which the layer exists is observed, as well as cases where it is formed in only a part of the region. In this disclosure, the term "stacked" refers to stacking layers, and two or more layers may be joined together, or two or more layers may be detachable.

[0014] <Sealing material> The sealing material of this disclosure comprises an epoxy resin, an inorganic filler, and a material with a density of 1.82 g / cm³. ３ The above carbon black is contained in the encapsulant. According to the encapsulant having the configuration of the present disclosure, laser marking properties are maintained when a encapsulated portion is formed, and the decrease in dielectric breakdown value is suppressed. The reason for this is not clear, but it is presumed to be as follows. In the present invention, the type of carbon black to be added was examined, and a density of 1.82 g / cm³ was found. ３ As a result, air is less likely to be entrained during the kneading process when preparing the sealing material, and the generation of voids is more easily suppressed. Consequently, it is believed that the sealing portion obtained using the sealing material of this disclosure will have a higher dielectric breakdown value.

[0015] (A) Epoxy resins As the epoxy resin, any epoxy resin commonly used as a encapsulant may be applied as appropriate. In particular, it is preferable that it contains two or more epoxy groups in one molecule. Specifically, novolac-type epoxy resins obtained by condensing or co-condensing a novolac resin obtained by condensing or co-condensing a novolac resin with a compound having an aldehyde group such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, salicylaldehyde, etc., under an acidic catalyst, including phenol novolac-type epoxy resins, orthocresol novolac-type epoxy resins, and epoxy resins having a triphenylmethane skeleton, as well as phenols such as cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, etc., and naphthols such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc., under an acidic catalyst; epoxy resins which are diglycidyl ethers of alkyl-substituted, aromatic ring-substituted, or unsubstituted bisphenol A, bisphenol F, bisphenol S, biphenol, thiodiphenol, etc.; stilbene-type epoxy resins Examples include lipids; hydroquinone-type epoxy resins; glycidyl ester-type epoxy resins obtained by the reaction of polybasic acids such as phthalic acid and dimer acid with epichlorohydrin; glycidylamine-type epoxy resins obtained by the reaction of polyamines such as diaminodiphenylmethane and isocyanuric acid with epichlorohydrin; dicyclopentadiene-type epoxy resins obtained by epoxidizing a co-condensation resin of dicyclopentadiene and phenols; epoxy resins having a naphthalene ring; phenol aralkyl resins synthesized from at least one of phenols and naphthols with dimethoxyp-xylene or bis(methoxymethyl)biphenyl; epoxidized aralkyl-type phenol resins such as naphthol aralkyl resins; trimethylolpropane-type epoxy resins; terpene-modified epoxy resins; linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid; and alicyclic epoxy resins. These may be used individually or in combination of two or more.

[0016] In particular, from the viewpoint of achieving both fluidity and curability, it is preferable that the epoxy resin contains a biphenyl-type epoxy resin, which is a diglycidyl ether of alkyl-substituted, aromatic ring-substituted, or unsubstituted biphenol. From the viewpoint of curability, it is preferable that it contains a novolac-type epoxy resin. From the viewpoint of low hygroscopicity, it is preferable that it contains a dicyclopentadiene-type epoxy resin. From the viewpoint of heat resistance and low warping, it is preferable that it contains a naphthalene-type epoxy resin. From the viewpoint of achieving both fluidity and flame retardancy, it is preferable that it contains a bisphenol F-type epoxy resin, which is a diglycidyl ether of alkyl-substituted, aromatic ring-substituted, or unsubstituted bisphenol F. From the viewpoint of achieving both fluidity and reflowability, it is preferable that it contains a thiodiphenol-type epoxy resin, which is a diglycidyl ether of alkyl-substituted, aromatic ring-substituted, or unsubstituted thiodiphenol. From the viewpoint of achieving both curability and flame retardancy, it is preferable that it contains an epoxidized phenol aralkyl resin synthesized from alkyl-substituted, aromatic ring-substituted, or unsubstituted phenol and dimethoxyp-xylene or bis(methoxymethyl)biphenyl. Furthermore, from the viewpoint of achieving both storage stability and flame retardancy, it is preferable that the product contains an epoxidized naphthol aralkyl resin synthesized from alkyl-substituted, aromatic ring-substituted, or unsubstituted naphthols and dimethoxy-paraxylene.

[0017] The epoxy equivalent of the epoxy resin is not particularly limited. From the viewpoint of balancing various properties such as moldability, heat resistance, and electrical reliability, the epoxy equivalent of the epoxy resin is preferably 100 g / eq. to 1000 g / eq., and more preferably 150 g / eq. to 500 g / eq. Here, epoxy equivalent refers to the mass (g) of one mole of epoxy groups contained in the epoxy resin.

[0018] Furthermore, the softening point or melting point of the epoxy resin is not particularly limited. In particular, from the viewpoint of moldability and heat resistance, the softening point or melting point is preferably 40°C to 180°C, and from the viewpoint of handling when manufacturing thermosetting resin molding materials, it is more preferably 50°C to 130°C.

[0019] From the viewpoints of moldability and heat resistance, the content of the epoxy resin in the sealing material is preferably 3% by mass to 15% by mass, preferably 0.4% by mass to 28% by mass, and more preferably 1.1% by mass to 26% by mass.

[0020] (B) Carbon black Carbon black has a density of 1.82 g / cm ３ or more, preferably 1.85 g / cm ３ or more, and more preferably 1.90 g / cm ３ or more. Also, from the viewpoint of better controlling the uneven distribution of carbon black, the density of carbon black is preferably 3.0 g / cm ３ or less, more preferably 2.8 g / cm ３ or less, still more preferably 2.6 g / cm ３ or less, and particularly preferably 2.4 or less.

[0021] The density of the carbon black generally used in the sealing material conventionally is about 1.80 g / cm ３ The carbon black according to the present disclosure can be obtained by heating in a state of blocking air and performing graphitization treatment.

[0022] The density of carbon black can be measured in accordance with JIS Z 8901:2006.

[0023] The carbon black according to the present disclosure may be used alone or in combination of two or more. As an embodiment of using two or more kinds of carbon black in combination, for example, when using two or more kinds of carbon black of the same type but different average particle diameters, when using two or more kinds of carbon black of the same average particle diameter but different types, and when using two or more kinds of carbon black of different average particle diameters and types. Examples of carbon black of different types include those with different degrees of graphitization and those with different densities.

[0024] From the perspective of heat resistance, the ash content of carbon black is preferably 0.15% by mass or less, more preferably 0.14% by mass or less, and even more preferably 0.12% by mass or less. The lower the ash content of carbon black, the more preferable it is, and the lower limit is not limited, and it may be 0% by mass (not contained).

[0025] The ash content of carbon black can be measured by thermogravimetric analysis (TGA) in accordance with K6218-2:2005.

[0026] From the perspective of heat resistance, the volatile content of carbon black is preferably 1.0% by mass or less, more preferably 0.8% by mass or less, and even more preferably 0.5% by mass or less. The lower the volatile content of carbon black, the more preferable it is, and the lower limit is not limited, and it may be 0% by mass (not contained).

[0027] The volatile content of carbon black can be measured by thermogravimetric analysis in accordance with K6218-1:2005.

[0028] From the perspective of heat resistance, the chlorine ion content of carbon black is preferably 15 ppm by mass or less, more preferably 10 ppm by mass or less, and even more preferably 0.5 ppm by mass or less. The lower the chlorine ion content of carbon black, the more preferable it is, and the lower limit is not limited, and it may be 0 ppm by mass (not contained). In the case of below the detection limit, it may be 0 ppm by mass (not contained).

[0029] The chlorine ion content of carbon black can be determined by using an ion chromatograph to quantify the chlorine ions in the sample by the calibration curve method and converting to the elemental content in the sample.

[0030] From the perspective of heat resistance, the sulfur content of carbon black is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.01% by mass or less. The lower the sulfur content of carbon black, the more preferable it is, and the lower limit is not limited, and it may be 0% by mass (not contained). In the case of below the detection limit, it may be 0% by mass (not contained).

[0031] The sulfur content of carbon black can be determined by using ion chromatography to quantify sulfate ions in the sample using a calibration curve method, and then converting this to the elemental content of the sample.

[0032] The sodium ion content of the carbon black is preferably 20 ppm by mass or less, more preferably 10 ppm by mass or less, and even more preferably 5 ppm by mass or less. A lower sodium ion content is preferable, and there is no lower limit; it may be 0 ppm by mass (no sodium ion content). In addition, if it is below the detection limit, it may be 0 ppm by mass (no sodium ion content).

[0033] The sodium ion content of carbon black can be determined by using on-chromatography to quantify the sodium ions in the sample using a calibration curve method, and then converting this to the elemental content in the sample.

[0034] The potassium ion content of carbon black is preferably 15 ppm by mass or less, more preferably 10 ppm by mass or less, and even more preferably 5 ppm by mass or less. A lower potassium ion content is preferable, and there is no lower limit; it may be 0 ppm by mass (no potassium ions). In addition, if the potassium ion content is below the detection limit, it may be 0 ppm by mass (no potassium ions).

[0035] The potassium ion content of carbon black can be determined by quantifying the potassium ions in the sample using an ion chromatograph and a calibration curve, and then converting this to the elemental content of the sample.

[0036] From the viewpoint of suppressing aggregation, the average particle size of carbon black is preferably 10 nm or more, more preferably 15 nm or more, and even more preferably 20 nm or more. From the viewpoint of colorability, the average particle size of carbon black is preferably 100 nm or less, more preferably 90 nm or less, and even more preferably 80 nm or less.

[0037] The average particle size of carbon black is measured using a laser diffraction particle size distribution analyzer and corresponds to the particle size that represents 50% of the cumulative volume particle size distribution from the small particle size side.

[0038] The BET specific surface area of ​​carbon black is 10 m² from the standpoint of colorability. ２ It is preferable that it be 20 m or more ２ It is more preferable that it be 25m or more per g. ２ It is even more preferable that the amount is 200 m² or more. The BET specific surface area of ​​carbon black is 200 m² from the viewpoint of dispersibility in resin. ２ It is preferable that it be less than or equal to 150m ２ It is more preferable that it be less than or equal to 100m ２ It is even more preferable that the amount is less than or equal to / g.

[0039] The BET specific surface area of ​​carbon black is calculated by the BET method after measuring nitrogen adsorption at liquid nitrogen temperature (77 K) using a multi-point method. When measuring the BET specific surface area, it is preferable to first perform a pretreatment to remove moisture by heating, as moisture adsorbed on the sample surface and within its structure is thought to affect the gas adsorption capacity.

[0040] The amount of DBP (dibutyl phthalate) absorbed by carbon black is 30 cm, from the perspective of insulation. ３ It is preferable that it be 100g or more, and 50cm ３ It is more preferable that the amount is 100g or more. The amount of DBP oil absorbed by carbon black should be 200cm from the viewpoint of dispersibility in the resin. ３ It is preferable that the amount be 100g or less, and 180cm ３ It is more preferable that the amount be 100g or less.

[0041] The amount of DBP absorbed by carbon black can be determined by using an absorption meter to calculate the amount of DBP dropped at 70% of the maximum torque, in accordance with the JIS K 6217-4:2017 standard.

[0042] From the viewpoint of printability, the carbon black content in the sealing material is preferably 0.20% by mass or more, more preferably 0.23% by mass or more, and even more preferably 0.26% by mass or more. From the viewpoint of suppressing dielectric breakdown, the carbon black content in the sealing material is preferably 0.35% by mass or less, more preferably 0.30% by mass or less, and even more preferably 0.28% by mass or less.

[0043] (C) The curing agent encapsulant may further contain at least one type of curing agent. The curing agent may be one that is commonly used in encapsulants. Examples of curing agents include acid anhydride-based curing agents, amine-based curing agents, phenol-based curing agents, mercaptan-based curing agents, and other latent curing agents such as imidazole. From the viewpoint of heat resistance and adhesion, amine-based curing agents or phenol-based curing agents are preferred. From the viewpoint of storage stability, phenol-based curing agents are preferred. Furthermore, from the viewpoint of obtaining a highly tough cured product, amine-based curing agents are preferred. One type of curing agent may be used alone, or two or more types may be used in combination.

[0044] As a phenolic curing agent, commonly used ones can be used without particular limitation. Examples of phenolic curing agents include novolac-type phenolic resins obtained by condensing or co-condensing at least one selected from the group consisting of phenols such as phenol, cresol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, thiodiphenol, and aminophenol, and naphthols such as α-naphthol, β-naphthol, and dihydroxynaphthalene, with a compound having an aldehyde group such as formaldehyde, benzaldehyde, and salicylaldehyde under an acidic catalyst; and at least one selected from the group consisting of phenols and naphthols. Examples include phenol aralkyl resins synthesized from dimethoxyp-xylene or bis(methoxymethyl)biphenyl; aralkyl-type phenol resins such as naphthol aralkyl resins; copolymer-type phenol aralkyl resins in which phenol novolac structures and phenol aralkyl structures are randomly, blocked, or alternately repeated; para-xylylene-modified phenol resins; meta-xylylene-modified phenol resins; melamine-modified phenol resins; terpene-modified phenol resins; dicyclopentadiene-modified phenol resins; cyclopentadiene-modified phenol resins; and polycyclic aromatic ring-modified phenol resins. These may be used individually or in combination of two or more.

[0045] In particular, phenol aralkyl resins and naphthol aralkyl resins are preferred from the viewpoint of fluidity, flame retardancy, and reflow resistance. Dicyclopentadiene-modified phenol resins are preferred from the viewpoint of low hygroscopicity. Novolac-type phenol resins are preferred from the viewpoint of curability. The curing agent preferably contains at least one of these phenol resins.

[0046] The hydroxyl group equivalent of the curing agent is not particularly limited. However, from the viewpoint of balancing various properties such as moldability, reflow resistance, and electrical reliability, it is preferably 70 g / eq. to 1000 g / eq., and more preferably 80 g / eq. to 500 g / eq. Furthermore, the softening point or melting point of the curing agent is not particularly limited. However, from the viewpoint of moldability and reflow resistance, it is preferably 40°C to 180°C, and from the viewpoint of ease of handling when manufacturing epoxy resin molding materials for sealing, it is more preferably 50°C to 130°C.

[0047] As the amine-based curing agent, any commonly used one can be used without particular restriction, and commercially available ones may also be used. One type of amine-based curing agent may be used alone, or two or more types may be used in combination. In particular, from the viewpoint of heat resistance, it is preferable to use an amine-based curing agent having a benzene ring or a naphthalene ring, and it is more preferable to use an amine-based curing agent having an amino group on the benzene ring or naphthalene ring. Furthermore, from the viewpoint of curability, it is preferable to use a polyfunctional amine-based curing agent having two or more amino groups. When epoxy resins having a mesogenic skeleton are cured using an amine-based curing agent, a cured product with high toughness tends to be obtained.

[0048] Examples of amine-based curing agents include 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 2,4,4'-triaminodiphenyl ether, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diamino-3 Examples include 3'-dimethoxybiphenyl, 4,4'-diaminophenylbenzoate, 1,5-diaminonaphthalene, 1,3-diaminonaphthalene, 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylenediamine, 4,4'-diaminobenzanilide, 3,3'-diaminobenzanilide, trimethylene-bis-4-aminobenzoate, 1,4-diaminonaphthalene, and 1,8-diaminonaphthalene. From the viewpoint of heat resistance and storage stability, 4,4'-diaminodiphenylsulfone is preferred.

[0049] The content of the curing agent is not particularly limited. For example, when a phenolic curing agent is used, the ratio of the number of equivalents of active hydrogen in the phenolic hydroxyl groups contained in the phenolic curing agent (number of equivalents of phenolic hydroxyl groups) to the number of equivalents of epoxy groups contained in the epoxy resin (number of equivalents of phenolic hydroxyl groups / number of equivalents of epoxy groups) is preferably 0.5 to 2.0, and more preferably 0.8 to 1.2. Also, for example, when an amine-based curing agent is used, from the viewpoint of efficiently carrying out the curing reaction, the ratio of the number of equivalents of active hydrogen in the amine-based curing agent to the number of equivalents of epoxy groups in the epoxy resin (number of equivalents of active hydrogen / number of equivalents of epoxy groups) is preferably 0.3 to 3.0, and more preferably 0.5 to 2.0.

[0050] (D) The curing accelerator sealant may further contain at least one curing accelerator. As the curing accelerator, any commonly used sealant may be applied as appropriate. Examples of curing accelerators include cycloamidine compounds such as 1,8-diazabicyclo[5.4.0]undecene-7, 1,5-diazabicyclo[4.3.0]nonene-5, and 5,6-dibutylamino-1,8-diazabicyclo[5.4.0]undecene-7; and these cycloamidine compounds may be mixed with maleic anhydride, 1,4-benzoquinone, 2,5-thulquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, and 2,3-dimethoxy-5. Compounds having intramolecular polarization obtained by adding quinone compounds such as methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, and phenyl-1,4-benzoquinone, as well as compounds having π bonds such as diazophenylmethane and phenolic resins; tertiary amine compounds such as benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol and their derivatives; 2-methylimidazole, 2-phenylimidazole Examples include imidazole compounds such as zole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole, and their derivatives; 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 quinone compounds, diazophenylmethane, and phenolic resins to these organic phosphine compounds; tetra-substituted phosphonium / tetra-substituted borates such as tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium ethyltriphenylborate, and tetrabutylphosphonium tetrabutylborate; tetraphenylboron salts such as 2-ethyl-4-methylimidazole tetraphenylborate and N-methylmorpholine tetraphenylborate, and their derivatives; and the like. These curing accelerators may be used individually or in combination of two or more.

[0051] There are no particular restrictions on the organic phosphine used in the adduct between an organic phosphine compound (tertiary phosphine) and a quinone compound. Examples of organic phosphine compounds include those having an aryl group, such as dibutylphenylphosphine, butyldiphenylphosphine, ethyldiphenylphosphine, triphenylphosphine, tris(4-methylphenyl)phosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(isopropylphenyl)phosphine, tris(tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, and tris(4-ethoxyphenyl)phosphine. Among these, triphenylphosphine is preferred from the viewpoint of moldability. Furthermore, there are no particular restrictions on the quinone compound used in the adduct between an organophosphine compound (tertiary phosphine) and a quinone compound. Examples of quinone compounds include o-benzoquinone, p-benzoquinone, diphenoquinone, 1,4-naphthoquinone, and anthraquinone. Among these, p-benzoquinone is preferred from the viewpoint of moisture resistance and storage stability.

[0052] If the sealing material contains a curing accelerator, the amount of the curing accelerator is not particularly limited as long as the curing acceleration effect is achieved. The content of the curing accelerator in the sealing material is preferably 0.05% to 5% by mass, and more preferably 0.1% to 1% by mass.

[0053] (E) The inorganic filler encapsulant contains an inorganic filler. Further inclusion of an inorganic filler more effectively reduces hygroscopicity, reduces the coefficient of thermal expansion, improves thermal conductivity, and improves strength. The inorganic filler is not particularly limited as long as it is commonly used in encapsulants. Examples of inorganic fillers include powders such as fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate, potassium titanate, silicon carbide, silicon nitride, aluminum nitride, boron nitride, beryllia, zirconia, zircon, fossilite, steatite, spinel, mullite, and titania, as well as beads formed from these, and glass fibers. These inorganic fillers may be used individually or in combination of two or more. Among these, fused silica is preferred from the viewpoint of reducing the coefficient of thermal expansion, and alumina is preferred from the viewpoint of high thermal conductivity. Furthermore, the shape of the inorganic filler is preferably spherical from the viewpoint of fluidity during molding and mold wear resistance. Spherical fused silica is particularly preferred as the inorganic filler from the viewpoint of balancing cost and performance.

[0054] The average particle size of the inorganic filler is not particularly limited. For example, the volume average particle size is preferably 0.2 μm to 80 μm, and more preferably 0.5 μm to 70 μm. When the volume average particle size is 0.2 μm or more, the increase in viscosity of the sealant tends to be further suppressed. When the volume average particle size is 80 μm or less, the ability to fill narrow gaps tends to be further improved. The volume average particle size of the inorganic filler can be measured as the volume average particle size (D50) using a laser diffraction scattering particle size distribution analyzer.

[0055] The volume-average particle size of inorganic fillers in encapsulants or their cured products can be measured by known methods. For example, inorganic fillers can be extracted from the encapsulant composition or cured product using an organic solvent, nitric acid, aqua regia, etc., and thoroughly dispersed using an ultrasonic disperser or the like to prepare a dispersion. Using this dispersion, the volume-average particle size of the inorganic fillers can be measured from the volume-based particle size distribution measured by a laser diffraction scattering particle size distribution analyzer. Alternatively, the volume-average particle size of the inorganic fillers can be measured from the volume-based particle size distribution obtained by embedding the cured product in a transparent epoxy resin or the like, polishing it, and observing the resulting cross-section with a scanning electron microscope. Furthermore, it can also be measured by continuously observing the two-dimensional cross-section of the cured product using a FIB (Focused Ion Beam SEM) and performing three-dimensional structural analysis.

[0056] From the viewpoint of flame retardancy, moldability, hygroscopicity, reduction of the coefficient of linear expansion, and improvement of strength, the inorganic filler content in the encapsulant is preferably 70% to 95% by mass. In this disclosure, carbon black is not included in the inorganic filler.

[0057] (F) Coupling agent The encapsulant may contain a coupling agent. The coupling agent plays a role in strengthening the adhesion between the resin component in the encapsulant and the inorganic filler, or between the resin component and components such as electronic components. The coupling agent is not particularly limited and can be selected from those commonly used as materials for encapsulants. Specifically, examples include silane compounds having primary, secondary, or tertiary amino groups, epoxysilanes, mercaptosilanes, alkylsilanes, ureidosilanes, vinylsilanes, and various other silane compounds, titanium compounds, aluminum chelates, and aluminum / zirconium compounds. Examples of these include vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-anilinopropyltrimethoxysilane, γ-anilinopropyltriethoxysilane, γ-(N-phenyl)aminopropyltrimethoxysilane, γ-(N γ-(N,N-dimethyl)aminopropyltrimethoxysilane, γ-(N,N-diethyl)aminopropyltrimethoxysilane, γ-(N,N-dibutyl)aminopropyltrimethoxysilane, γ-(N-methyl)anilinopropyltrimethoxysilane, γ-(N,N-ethyl)anilinopropyltrimethoxysilane, γ-(N,N-dimethyl)aminopropyltriethoxysilane, γ-(N,N-diethyl)aminopropyltriethoxysilane, γ-(N,N-dibutyl)aminopropyltriethoxysilane, γ-(N-methyl)anilinopropyltriethoxysilane, γ-(N-ethyl)anilinopropyltriethoxysilane, γ-(N,N-dimethyl)aminopropylmethyldimethoxysilane, γ-(N,Silane coupling agents such as N-dibutyl)aminopropylmethyldimethoxysilane, γ-(N-methyl)anilinopropylmethyldimethoxysilane, γ-(N-ethyl)anilinopropylmethyldimethoxysilane, N-(trimethoxysilylpropyl)ethylenediamine, N-(dimethoxymethylsilylisopropyl)ethylenediamine, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, vinyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, tetrasulfideditriethoxysilane, isopropyltriisostearoyl titanate, isopropyltris(dioctylpyrophosphate) titanate, isopropyltri(N-aminoethyl Examples of titanium coupling agents include -aminoethyl) titanate, tetraoctylbis(ditridecylphosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecylphosphite) titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, bis(dioctyl pyrophosphate) ethylene titanate, isopropyltrioctanoyl titanate, isopropyl dimethacrylate isostearoyl titanate, isopropyl toridodecylbenzenesulfonyl titanate, isopropyl isostearoyl diacrylic titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, and tetraisopropylbis(dioctylphosphite) titanate. The coupling agent may be used individually or in combination of two or more types.

[0058] When the encapsulant contains a coupling agent, the epoxy resin content in the encapsulant is preferably 0.01% to 2.0% by mass, and more preferably 0.1% to 1.5% by mass. When the amount of coupling agent is 0.01% by mass or more, a sufficient effect of improving the dispersibility of the filler tends to be obtained, and when it is 2.0% by mass or less, the generation of voids in the cured product tends to be suppressed.

[0059] (G) Other additives The encapsulant may further contain, as necessary, anion exchangers, release agents, flame retardants, other colorants other than carbon black, etc.

[0060] The encapsulant may further contain an anion exchanger as needed. Including an anion exchanger can further improve the moisture resistance and high-temperature storage characteristics of the IC. There are no particular restrictions on the anion exchanger; conventionally known ones can be used. Examples of anion exchangers include hydrotalcites, hydrated oxides of metal elements selected from the group consisting of magnesium, aluminum, titanium, zirconium, and bismuth. These anion exchangers may be used individually or in combination of two or more types.

[0061] When the encapsulating material contains an anion exchanger, the amount of anion exchanger is not particularly limited as long as it is in a sufficient amount to capture anions such as halogen ions. The amount of anion exchanger is preferably 0.1 to 30 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of epoxy resin.

[0062] The sealing material may further contain at least one type of release agent as needed. Examples of release agents include low molecular weight polyethylene with a number average molecular weight of about 500 to 10,000, such as the PE and PED series manufactured by Clariant Japan Co., Ltd., which are oxidized or non-oxidized polyolefins. Other release agents include carnauba wax, montanic acid ester, montanic acid, and stearic acid. These release agents may be used individually or in combination of two or more.

[0063] When the encapsulant contains an oxidized or non-oxidized polyolefin as a release agent, its content is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass or less, per 100 parts by mass of epoxy resin. A content of 0.01 parts by mass or more tends to provide sufficient release properties. A content of 10 parts by mass or less tends to further improve adhesion. When the encapsulant contains other release agents in addition to the oxidized or non-oxidized polyolefin as a release agent, the total content of the release agent is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 3 parts by mass, per 100 parts by mass of epoxy resin.

[0064] The sealing material may further contain at least one adhesion promoter as needed. Examples of adhesion promoters include derivatives of imidazole, triazole, tetrazole, triazine, anthranilic acid, gallic acid, malonic acid, malic acid, maleic acid, aminophenol, quinoline, and their derivatives, aliphatic acid amide compounds, dithiocarbamates, and thiadiazole derivatives. These may be used individually or in combination of two or more.

[0065] The sealing material may further contain at least one of the conventionally known flame retardants as needed. Examples of flame retardants include phosphorus compounds such as red phosphorus coated with inorganic materials such as brominated epoxy resin, antimony trioxide, red phosphorus, aluminum hydroxide, magnesium hydroxide, zinc oxide, and / or thermosetting resins such as phenolic resin, melamine, melamine derivatives, melamine-modified phenolic resins, compounds having a triazine ring, nitrogen-containing compounds such as cyanuric acid derivatives and isocyanuric acid derivatives, phosphorus and nitrogen-containing compounds such as cyclophosphazene, and compounds containing metallic elements such as aluminum hydroxide, magnesium hydroxide, zinc oxide, zinc stinate, zinc borate, iron oxide, molybdenum oxide, zinc molybdate, and dicyclopentadienyl iron. These flame retardants may be used individually or in combination of two or more.

[0066] If the sealing material contains a flame retardant, its content is not particularly limited. The flame retardant content is preferably 1 to 30 parts by mass, and more preferably 2 to 15 parts by mass, per 100 parts by mass of epoxy resin.

[0067] The encapsulant may further contain other colorants besides carbon black. Examples of other colorants include organic dyes, organic pigments, titanium dioxide, red lead, and red iron oxide. Further additives such as stress relievers, including silicone oil and silicone rubber powder, may be added as needed.

[0068] <Physical Properties of the Sealing Material> From the viewpoint of fluidity, the spiral flow of the sealing material, as determined by the following method, is preferably 100 cm or more, more preferably 105 cm or more, and even more preferably 110 cm or more. The upper limit of the spiral flow is not particularly limited and may be 200 cm or less.

[0069] Spiral flow measurement is performed by determining the flow distance when the sealing material is molded using a spiral flow measurement mold conforming to EMMI-1-66 under the conditions of a mold temperature of 175°C, a molding pressure of 6.9 MPa, and a curing time of 90 seconds.

[0070] From the viewpoint of fluidity, the gel time of the sealing material at 175°C is preferably 15 seconds or more, more preferably 18 seconds or more, even more preferably 20 seconds or more, and particularly preferably 21 seconds or more. From the viewpoint of curability, the gel time is preferably 50 seconds or less, more preferably 47 seconds or less, and even more preferably 44 seconds or less.

[0071] Gel time is measured from the time 0.5 g of the sealant is placed on a hot plate preheated to 175°C until the sealant loses its viscosity. It is preferable to heat the sealant while periodically stirring it with a spatula or similar tool. "Loss of viscosity of the sealant" refers to the phenomenon where the sealant breaks or breaks when kneaded with a spatula or similar tool.

[0072] The viscosity of the sealing material at 175°C is preferably 0.01 Pa·s to 1000 Pa·s, more preferably 0.1 Pa·s to 200 Pa·s, even more preferably 1 Pa·s to 50 Pa·s, and particularly preferably 1 Pa·s to 20 Pa·s. The viscosity of the sealing material at 175°C is measured using a flow tester viscometer at a pressure of 1 MPa, a nozzle diameter of 1 mm, and a length of 10 mm.

[0073] The cured product obtained by the encapsulant preferably has a dielectric breakdown voltage of 16 kV / mm or higher, more preferably 18 kV / mm or higher, and even more preferably 20 kV / mm or higher, as determined by the short-time method described below. There is no particular upper limit to the dielectric breakdown voltage determined by the short-time method.

[0074] The short-time method for measuring dielectric breakdown voltage is performed in accordance with JIS-K-6911:2006, 5.11.3. The voltage is applied from zero and increased at a constant rate such that dielectric breakdown of the sample occurs over an average of 10 to 20 seconds. The breakdown voltage at which the test piece breaks is then measured. This procedure is performed three times, and the average value of the three measurements is divided by the measured average thickness of the test piece to obtain the short-time method dielectric breakdown voltage (kV / mm).

[0075] The cured product obtained by the sealing material preferably has a dielectric breakdown voltage of 12 kV / mm or higher, more preferably 14 kV / mm or higher, and even more preferably 16 kV / mm or higher, as determined by the following step-by-step method. A higher dielectric breakdown voltage determined by the step-by-step method is preferable, and there is no particular upper limit.

[0076] The step-by-step method for measuring dielectric breakdown voltage shall be performed in accordance with JIS-K-6911:2006, 5.11.3. The breakdown voltage shall be determined by the short-time method, and the voltage closest to 40% of that value shall be selected from the step voltages listed below. If the test specimen does not undergo dielectric breakdown after applying this voltage for 20 seconds, the next higher voltage shall be applied for 20 seconds each, and the test shall be continued until dielectric breakdown occurs. The voltage increase from one step to the next shall be performed as quickly as possible. In this case, the time required for this increase shall be included in the 20 seconds of the next step. The highest step voltage at which dielectric breakdown did not occur after 20 seconds shall be considered the dielectric breakdown voltage. This operation shall be performed three times, and the average value of the three measurements shall be divided by the measured average thickness of the test specimen to obtain the dielectric breakdown voltage (kV / mm) using the step method. Step voltage (kV): 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, 26, 28, 30, 32, 34, 36, 36, 38, 40, 42, 44, 46, 48, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100

[0077] The dielectric constant at 1 MHz of the cured product obtained by molding the sealing material under the conditions of a mold temperature of 175°C, a molding pressure of 6.9 MPa, a curing time of 90 seconds, and post-curing at 175°C for 6 hours is preferably 30 or less, more preferably 15 or less, and even more preferably 5 or less.

[0078] The dielectric constant is measured using a dielectric constant measuring device (for example, Agilent Technologies, product name "Network Analyzer N5227A") at a temperature of 25 ± 3°C.

[0079] The dielectric loss tangent at 1 MHz of the cured product obtained by molding the sealing material under the conditions of a mold temperature of 175°C, a molding pressure of 6.9 MPa, a curing time of 90 seconds, and post-curing at 175°C for 6 hours is preferably 0.011 or less, and more preferably 0.010 or less.

[0080] The dielectric loss tangent is measured using a dielectric constant measuring device (for example, Agilent Technologies, product name "Network Analyzer N5227A") at a temperature of 25 ± 3°C.

[0081] <Method for Manufacturing Sealing Material> There are no limitations on the method for manufacturing sealing material as long as the various components can be uniformly dispersed and mixed. A common method involves thoroughly mixing predetermined amounts of components using a mixer, then melt-kneading them using a mixing roll, extruder, etc., followed by cooling and pulverization. Alternatively, the sealing material can be obtained by uniformly stirring and mixing predetermined amounts of the above-mentioned components, kneading them in a kneader, roll, extruder, etc., preheated to 70°C to 140°C, then cooling and pulverizing. Furthermore, sealing material is easier to use when it is made into tablets with dimensions and mass that suit the molding conditions.

[0082] <Semiconductor Device> The semiconductor device of this disclosure comprises an element and a cured product of the sealing material that seals the element. Examples of semiconductor devices include electronic component devices in which a semiconductor chip, an active element such as a transistor, a diode, or a thyristor, and a passive element such as a capacitor, a resistor, or a coil are mounted on a support member such as a lead frame, a wired tape carrier, a wiring board, glass, or a silicon wafer, and the necessary parts are sealed with the sealing material of this disclosure. In particular, the sealing material of this disclosure can be suitably used for sealing power semiconductors from the viewpoint of maintaining the dielectric breakdown value. The most common method for sealing an element using the sealing material of this disclosure is transfer molding, but injection molding, compression molding, etc., may also be used.

[0083] Figure 1 is a schematic cross-sectional view showing an example of the configuration of the semiconductor device 10 of this disclosure. The semiconductor device 10 has a semiconductor chip (element) 20, a lead frame 30, and a sealing portion 40. The semiconductor chip 20 is mounted on the lead frame 30. The lead frame 30 is manufactured by precision pressing (punching, drawing, bending, etc.) of a thin sheet of Cu alloy material or Fe alloy material that has excellent electrical conductivity, mechanical strength, thermal conductivity, corrosion resistance, etc. The lead frame 30 has a die pad 31 on which the semiconductor chip 20 is mounted, and leads 33 connected to the die pad 31.

[0084] The die pad 31 has a plurality of electrically isolated segments 32, each corresponding to a plurality of connection terminals 55 of the semiconductor chip 20. Each of the plurality of connection terminals 55 is connected to the corresponding segment 32 among the plurality of segment segments 32. The connection terminals 55 are made of solder balls. The rewiring (not shown) of the semiconductor chip 20 and the die pad 31 of the lead frame 30 are electrically connected by the connection terminals 55. In this form of semiconductor device 10, bonding wires are not used for the electrical connection between the semiconductor chip 20 and the lead frame 30. Note that the connection terminals 55 may be made of something other than solder balls. For example, solder paste or conductive adhesive supplied onto the die pad 31 may be used to connect the rewiring to the die pad 31. Alternatively, the semiconductor chip 20 and the lead frame 30 may be electrically connected by bonding wires instead of the connection terminals 55.

[0085] The sealing portion 40 seals the die pad 31 and the semiconductor chip 20. That is, the die pad 31 and the semiconductor chip 20 are embedded inside the sealing portion 40. The sealing portion 40 is a cured product of the sealing material of this disclosure. The leads 33 connected to each of the segmented pieces 32 of the die pad 31 extend to the outside of the sealing portion 40.

[0086] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0087] <Preparation of sealing material> Each of the materials listed below was blended in the parts by mass shown in Table 1 below, and roll kneading was performed at a kneading temperature of 80°C for a kneading time of 10 minutes to prepare the sealing materials of Examples 1 to 5 and Comparative Examples 1 to 5.

[0088] (A) Epoxy resin / Epoxy resin 1: Triphenylmethane type epoxy resin with epoxy equivalent of 163-175 g / eq. and a softening point of 57°C-63°C / Epoxy resin 2: Biphenyl type epoxy resin with epoxy equivalent of 195 g / eq. and a softening point of 105°C

[0089] (B) Carbon Black Carbon 1: Density 1.79 g / cm³ ３ , average particle diameter 24 nm, BET specific surface area 110 m ２ / g, DBP oil absorption 100cm ３ / 100g, volatile matter 1.9% by mass, ash 0.01% by mass • Carbon 2: density 1.80g / cm ３ Average particle diameter 20 nm, BET specific surface area 140 m² ２ / g, DBP oil absorption 129cm ３ / 100g, volatile matter 1.5% by mass, ash 0.02% by mass • Carbon 3: density 1.81g / cm ３ Average particle diameter 25 nm, BET specific surface area 225 m² ２ / g, DBP oil absorption 155cm ３ / 100g, volatile content 1.4% by mass, ash content 0.06% by mass, sulfur 0.5% by mass, ナトリウムイオン55% by mass pm, カリウムイオン18 mass ppm, カイオン1 mass ppm or less・カーボン4: Density 2.05g / cm ３ Average particle diameter 70 nm, BET specific surface area 27 m² ２ / g, DBP oil absorption 60cm ３ / 100g, volatile content 0.12 mass%, ash content 0.02 mass%, sulfur 0.002 mass%, natrotron 5 masspp m or less, カリウムイオン3 mass ppm or less, イイオン 10 mass ppm or less・カーボン5: Density 1.93g / cm ３ Average particle diameter 40 nm, BET specific surface area 57 m² ２ / g, DBP oil absorption 161cm ３ / 100g, volatile content 0.38% by mass, ash content 0.08% by mass, sulfur 0.005% by mass, ナトリウムイオン 5 masspp m or less, カリウムイオン3 mass ppm or less, イイオン 10 mass ppm or less・カーボン6: Density 1.82g / cm ３ Average particle diameter 25 nm, BET specific surface area 95 m² ２ / g, DBP oil absorption 125cm ３ / 100g, volatile content 0.12 mass%, ash content 0.11 mass%, sulfur 0.004 mass%, natrotron 5 masspp m or less, カリウムイオン3 mass ppm or less, chlorine 10 mass ppm or less ・Black acidified チタン: Density 3.9g / cm ３

[0090] (C) Curing agent / Phenol resin 1: Hydroxyl group equivalent 205 g / eq., phenol aralkyl type phenol resin with a softening point of 60°C to 70°C; Phenolic resin 2: Hydroxyl group equivalent 108 g / eq., phenol novolac resin with a softening point of 65°C

[0091] (D) Curing accelerator: 2-phenyl-4-methylimidazole

[0092] (E) Inorganic filler - Inorganic filler 1: Spherical fused silica with an average particle size of 19.4 μm - Inorganic filler 2: Spherical fused silica with an average particle size of 0.6 μm

[0093] (F) Coupling agents Coupling agent 1: N-phenyl-3-aminopropyltrimethoxysilane Coupling agent 2: 3-mercaptopropyltrimethoxysilane Coupling agent 3: Tetrasulfide ditriethoxysilane

[0094] • Release agent 1: Carnauba wax • Release agent 2: Montanoic acid ester • Adhesion promoter: Gallic acid

[0095] <Evaluation> The sealing materials of the examples and comparative examples obtained above were evaluated by various characteristic tests (1) to (3). The evaluation results are shown in Table 1 below. The sealing materials were molded using a transfer molding machine at a mold temperature of 175°C, a molding pressure of 6.9 MPa, and a curing time of 90 seconds, followed by post-curing at 175°C for 6 hours. Tests (4) and (5) were performed on the cured products of the obtained sealing materials. The evaluation results are shown in Tables 1 and 2 below.

[0096] (1) The spiral flow of the spiral flow encapsulant was measured using the method described above.

[0097] (2) The viscosity of the viscous sealing material at 175°C was measured using a flow tester viscometer in the manner described above.

[0098] (3) The gel time of the gel time of the gel time encapsulating material at 175°C was measured using the method described above.

[0099] (4) Dielectric breakdown voltage The dielectric breakdown voltage of the obtained cured material was measured using an automatic dielectric breakdown voltage measuring device (HAT-300S manufactured by Resonaq Corporation) in the manner described above. The thickness of the measurement sample was 2.0 mm.

[0100] (5) Dielectric Properties The dielectric constant and dielectric loss tangent of the hardened product were determined by the method described above.

[0101] (6) Printability The hardened material (50 mm in diameter, 3 mm in thickness) was imprinted on a disc using a UV laser marker manufactured by Keyence Corporation. Printability was evaluated according to the following criteria: A: Has visibility equal to or better than Comparative Example 1. B: Has inferior visibility compared to Comparative Example 1.

[0102] (7) The color of the samples used for evaluating color printability was visually evaluated by the evaluator according to the following criteria: A: Has the same black color as Comparative Example 1 B: Compared to Comparative Example 1, the black is lighter and closer to other colors.

[0103]

[0104] As shown in Table 1, Examples 1 to 5 had higher dielectric breakdown voltages compared to Comparative Examples 1 to 4. Furthermore, since Examples 1 to 5 contained the same amount of carbon black as Comparative Examples 1 to 4, their laser marking properties were equally excellent. On the other hand, while Comparative Example 5 had a high dielectric breakdown voltage, the cured product was not black, resulting in inferior laser marking properties compared to Examples 1 to 5. Also, Examples 1 to 5 had similarly low dielectric constants and significantly lower dielectric loss tangents compared to Comparative Examples 1, 2, 4, and 5 (data for Comparative Example 3 is unavailable).

[0105] The disclosure of Japanese Patent Application No. 2024-180822 is incorporated in its entirety by reference. All documents, patent applications, and technical standards in this disclosure are incorporated by reference to the same extent as if each individual document, patent application, and technical standard had been specifically and individually noted as being incorporated by reference.

[0106] 10 Semiconductor device 20 Semiconductor chip 30 Lead frame 31 Die pad 32 Divided piece 33 Lead 40 Encapsulating member 55 Connection terminal

Claims

1. Epoxy resin, inorganic filler, and a density of 1.82 g / cm³ ３ The carbon black and the encapsulating material containing it.

2. The sealing material according to claim 1, wherein the volatile content of the carbon black is 1.0% by mass or less.

3. The sealing material according to claim 1 or claim 2, wherein the ash content of the carbon black is 0.15% by mass or less.

4. The sealing material according to claim 1 or claim 2, wherein the chloride ion content of the carbon black is 15 ppm by mass or less.

5. The sealing material according to claim 1 or claim 2, wherein the sulfur content of the carbon black is 0.1% by mass or less.

6. The sealing material according to claim 1 or claim 2, wherein the sodium ion content of the carbon black is 20 ppm by mass or less.

7. The sealing material according to claim 1 or claim 2, wherein the potassium ion content of the carbon black is 15 ppm by mass or less.

8. The sealing material according to claim 1 or claim 2, wherein the average particle size of the carbon black is 10 nm or more.

9. The encapsulating material according to claim 1 or claim 2, for encapsulating power semiconductors.

10. A semiconductor device comprising: a semiconductor chip; a lead frame on which the semiconductor chip is mounted; and a cured product of the sealing material according to claim 1 or claim 2 for sealing the semiconductor chip.

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