JP7582179B2 - Encapsulating composition and semiconductor device - Google Patents

Description

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

In recent years, with miniaturization and high integration, there has been concern about heat generation inside semiconductor packages. Since heat generation may cause a decrease in the performance of electric or electronic components that have semiconductor packages, materials used in semiconductor packages are required to have high thermal conductivity. Therefore, there is a demand for high thermal conductivity of the encapsulating material of semiconductor packages.
On the other hand, materials used in semiconductor packages are also required to have durability in temperature cycle tests.
For example, when the inorganic filler is highly filled, the thermal conductivity of the encapsulant can be increased, but the elastic modulus increases, which may reduce durability in a temperature cycle test, and there is a trade-off between increasing the thermal conductivity and decreasing the elastic modulus of the encapsulant. Therefore, it may be difficult to achieve both high thermal conductivity and low elastic modulus at the same time.

An example of an encapsulating material highly filled with inorganic filler is an epoxy resin composition for semiconductor encapsulation, the essential components of which are (A) an epoxy resin, (B) a curing agent, and (D) an inorganic filler containing spherical alumina and spherical silica, the spherical alumina including (d1) a first spherical alumina having an average particle size of 40 μm or more and 70 μm or less, and (d2) a second spherical alumina having an average particle size of 10 μm or more and 15 μm or less, and the spherical silica including (d3) an average particle size of 4 μm or more and 8 μm or less. An epoxy resin composition for semiconductor encapsulation is known, which comprises (d3) a first spherical silica having an average particle size of 0.05 μm or less, (d4) a second spherical silica having an average particle size of 0.05 μm or more and 1.0 μm or less, wherein the total amount of (d3)+(d4) is 17% or more and 23% or less based on the total inorganic filler, the ratio of (d3)/(d4) is (d3)/(d4)=1/8 or more and 5/4 or less, and the amount of the inorganic filler is 85 to 95 mass% of the total resin composition (see, for example, Patent Document 1).

JP 2006-273920 A

However, in the epoxy resin composition for semiconductor encapsulation described in Patent Document 1, the elastic modulus of the encapsulant (i.e., the cured product of the epoxy resin composition for semiconductor encapsulation) can be increased by highly loading alumina, which is a highly thermally conductive filler. Therefore, the development of a highly thermally conductive encapsulant with a low elastic modulus is a difficult task.

The present disclosure has been made in consideration of the above-mentioned conventional circumstances, and aims to provide a sealing composition and a semiconductor device using the sealing composition that improves the thermal conductivity of the cured product while keeping the elastic modulus of the cured product low at high temperatures (260°C).

Specific means for achieving the above object are as follows.
＜1＞
a first epoxy resin having, in its molecule, at least two benzene rings and at least one ether bond connecting the two benzene rings directly or via a linking group, the two benzene rings having no substituents at the ortho- and meta-positions relative to the bonding positions of the ether bonds;
A hardener;
An inorganic filler;
A sealing composition comprising:
＜2＞
The sealing composition according to <1>, wherein a content of the inorganic filler is 78 volume % or more based on the entire sealing composition.
＜3＞
The encapsulating composition according to <1> or <2>, further comprising a second epoxy resin having a melting point or softening point of 50° C. or higher.
＜4＞
The sealing composition according to <3>, wherein a content of the second epoxy resin is 80 mass % or less based on a total amount of the epoxy resins contained in the sealing composition.
＜5＞
The sealing composition according to <3> or <4>, wherein the content of the second epoxy resin is 50 mass % or more based on the total amount of the epoxy resins contained in the sealing composition.
＜6＞
The sealing composition according to any one of <1> to <5>, wherein the first epoxy resin has two epoxy groups in a molecule.
＜７＞
The sealing composition according to any one of <1> to <6>, wherein the ether bond is directly bonded to at least one of the two benzene rings.
＜8＞
The sealing composition according to any one of <1> to <7>, wherein the group connecting the two benzene rings is a group consisting of one of the ether bonds.
＜9＞
The sealing composition according to any one of <1> to <7>, wherein the group connecting the two benzene rings is a group containing two or more of the ether bonds.
＜10＞
The sealing composition according to <9>, wherein the group connecting the two benzene rings is a divalent linking group represented by the following structural formula (1):

In the above structural formula (1), * indicates the bond to the benzene ring.
<11>
The encapsulating composition according to any one of <1> to <10>, further comprising a third epoxy resin other than the first epoxy resin, the third epoxy resin having a benzene ring and at least two epoxy groups bonded directly or via a linking group to para positions of the benzene ring, and the benzene ring having no substituents at ortho and meta positions relative to the bonding positions of the two epoxy groups.
＜12＞
A semiconductor device comprising: a semiconductor element; and a cured product of the encapsulating composition according to any one of <1> to <11>, which encapsulates the semiconductor element.

According to the present disclosure, it is possible to provide a sealing composition and a semiconductor device using the sealing composition that improves the thermal conductivity of the cured product while keeping the elastic modulus of the cured product low at high temperatures (260°C).

Below, the embodiments for implementing the sealing composition and semiconductor device of the present invention are described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including element steps, etc.) are not essential unless specifically stated. The same applies to numerical values and their ranges, and do not limit the present invention.

In the present disclosure, the numerical ranges indicated using "to" include the numerical values before and after "to" 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.
In the present disclosure, the particles corresponding to each component may include multiple types. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.
In the present disclosure, the term "(meth)acryloyl group" means at least one of an acryloyl group and a methacryloyl group, "(meth)acrylic" means at least one of an acrylic group and a methacrylic group, and "(meth)acrylate" means at least one of an acrylate and a methacrylate.

<Sealing composition>
The sealing composition of the present disclosure contains a first epoxy resin having, in its molecule, at least two benzene rings and at least one ether bond connecting the two benzene rings directly or via a linking group, and the two benzene rings do not have substituents at the ortho- and meta-positions of the bonding positions of the ether bonds; a curing agent; and an inorganic filler.

Since the sealing composition of the present disclosure contains the first epoxy resin, the elastic modulus at high temperature (260° C.) (hereinafter also referred to as “high temperature elastic modulus”) of the cured product is kept low, and the thermal conductivity of the cured product is improved. The reason for this is unclear, but is presumed to be as follows.
It is believed that the first epoxy resin having no substituents at the ortho and meta positions is more easily oriented and has higher crystallinity than an epoxy resin having a substituent, and therefore is more likely to undergo molecular vibration, reducing heat loss and enabling the cured product to have high thermal conductivity. In addition, it is believed that the first epoxy resin has flexibility due to the ether bond connecting two benzene rings, and therefore can improve the thermal conductivity of the cured product while suppressing an increase in the high-temperature elastic modulus of the cured product.

The components constituting the sealing composition are described below. The sealing composition of the present disclosure contains an epoxy resin, a curing agent, and an inorganic filler, and may contain other components as necessary.

-Epoxy resin-
Epoxy resins are generally those obtained by epoxidizing novolak resins obtained by condensing or co-condensing at least one selected from the group consisting of phenolic compounds (phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F, etc.) and naphthol compounds (α-naphthol, β-naphthol, dihydroxynaphthalene, etc.) with aldehyde compounds (formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, salicylaldehyde, etc.) under an acidic catalyst (phenol novolak type epoxy resin, orthocresol novolak type epoxy resin, etc.); bisphenols (bisphenol A, bisphenol AD, bisphenol F, bisphenol S, etc.). and at least one diglycidyl ether selected from the group consisting of biphenols (such as alkyl-substituted or 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 (such as phthalic acid and dimer acid) with epichlorohydrin; glycidyl amine type epoxy resins obtained by reacting polyamines (such as diaminodiphenylmethane and isocyanuric acid) with epichlorohydrin; linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids (such as peracetic acid); alicyclic epoxy resins; and the like. The epoxy resins may be used alone or in combination of two or more.

Among these epoxy resins, the encapsulating composition of the present disclosure contains a first epoxy resin having, in the molecule, at least two benzene rings and at least one ether bond linking the two benzene rings directly or via a linking group, and the two benzene rings do not have substituents at the ortho- and meta-positions relative to the bonding positions of the ether bonds, as described above.
In addition, the sealing composition of the present disclosure may contain an epoxy resin other than the first epoxy resin and the third epoxy resin described below, if necessary, and preferably further contains a second epoxy resin having a melting point or softening point of 50° C. or higher as a resin other than the first epoxy resin and the third epoxy resin described below.
Furthermore, the encapsulating composition of the present disclosure may contain, as necessary, a third epoxy resin other than the first epoxy resin, which has a benzene ring and at least two epoxy groups bonded directly or via a linking group to the para-position of the benzene ring, and the benzene ring does not have substituents at the ortho- and meta-positions relative to the bonding positions of the two epoxy groups.
The encapsulating composition of the present disclosure may contain an epoxy resin other than the first epoxy resin, the second epoxy resin, and the third epoxy resin (hereinafter also referred to as "other epoxy resins") as necessary. However, the total content of the first epoxy resin and the second epoxy resin and the third epoxy resin contained as necessary is preferably 90 mass% or more, more preferably 95 mass% or more, and even more preferably 98 mass% or more, based on the total amount of all epoxy resins contained in the encapsulating composition.

(First Epoxy Resin)
The first epoxy resin is not particularly limited as long as it is an epoxy resin having at least two benzene rings and at least one ether bond linking the two benzene rings directly or via a linking group in the molecule, and the two benzene rings do not have substituents at the ortho and meta positions of the bonding positions of the ether bonds.
Hereinafter, the benzene rings linked by the ether bonds are also referred to as "specific benzene rings".

The number of specific benzene rings that the first epoxy resin has in one molecule is not particularly limited as long as it is at least 2 or more, and can be in the range of 2 to 6, preferably 2 to 4, and more preferably 2.
The first epoxy resin may have an aromatic hydrocarbon ring other than the specific benzene ring bonded to the specific benzene ring directly or via a linking group. When the first epoxy resin has an aromatic hydrocarbon ring other than the specific benzene ring, the aromatic hydrocarbon ring possessed by the first epoxy resin may be one type or may be two or more types. When the first epoxy resin has an aromatic hydrocarbon ring other than the specific benzene ring, the number of aromatic hydrocarbon rings possessed by the first epoxy resin may be two or more, may be in the range of 2 to 4, or may be 2. Examples of aromatic hydrocarbon rings other than the specific benzene ring include a benzene ring and a naphthalene ring, and among these, a benzene ring is preferred.
When the first epoxy resin has a benzene ring as an aromatic hydrocarbon ring other than the specific benzene ring, it is preferable that the benzene ring other than the specific benzene ring does not have a substituent at the ortho-position and meta-position of the bonding position of the specific benzene ring.

The first epoxy resin has at least two epoxy groups in one molecule. The number of epoxy groups in one molecule of the first epoxy resin is not particularly limited as long as it is two or more, and may be 2 to 8, preferably 2 to 6, more preferably 2 to 3, and particularly preferably 2.
The epoxy group may be contained in the molecule of the first epoxy resin as part of at least one group selected from a glycidyl group, a glycidyloxy group, a glycidyloxycarbonyl group, a glycidylamino group, an epoxycycloalkyl group (an epoxycyclopentyl group, an epoxycyclohexyl group, an epoxycyclooctyl group, etc.), and the like.
Among them, the first epoxy resin preferably has a glycidyloxy group in the molecule, and more preferably has a glycidyloxy group in the molecule that is directly bonded to the specific benzene ring or an aromatic hydrocarbon ring other than the specific benzene ring. In other words, the glycidyloxy group may be directly bonded to the specific benzene ring, or may be directly bonded to an aromatic hydrocarbon ring other than the specific benzene ring.
Furthermore, when the first epoxy resin has two or more glycidyloxy groups, it is preferable that all of the two or more glycidyloxy groups are directly bonded to at least one selected from the specific benzene ring and the aromatic hydrocarbon ring other than the specific benzene ring, it is more preferable that all of the two or more glycidyloxy groups are directly bonded to the specific benzene ring or to an aromatic hydrocarbon ring other than the specific benzene ring, and it is even more preferable that all of the two or more glycidyloxy groups are directly bonded to the specific benzene ring or to a benzene ring other than the specific benzene ring.

The first epoxy resin may have at least one ether bond between the two specific benzene rings in one molecule, and may have two or more ether bonds between the two specific benzene rings.
The ether bond is preferably directly bonded to the specific benzene ring, or may be bonded to the specific benzene ring via a linking group other than an ether bond (a hydrocarbon group such as a substituted or unsubstituted alkylene group, a carbonyl group, etc.). The group linking two specific benzene rings may be a group consisting of one ether bond, a group containing an ether bond and a linking group other than an ether bond, a group containing two or more ether bonds, or a group containing two or more ether bonds and a linking group other than an ether bond.
Examples of the group containing two or more ether bonds and a linking group other than an ether bond include a divalent linking group represented by the following structural formula (1).
In the following structural formula (1), * indicates a bond to a specific benzene ring.

The first epoxy resin may further have other substituents (alkyl groups, alkoxy groups, aryl groups, aralkyl groups, amino groups, etc.).

An example of the first epoxy resin is an epoxy resin represented by the following general formula (2).

In the above general formula (2), ^E1 and ^E2 each independently represent a monovalent group containing an epoxy group, ^L1 represents a divalent linking group containing an ether bond, ^L2 and ^L3 each independently represent a divalent linking group containing an aromatic hydrocarbon ring, a1 and a2 each independently represent an integer of 0 to 3, and n represents an integer of 1 to 4.

Examples of the monovalent groups represented by ^E1 and ^E2 in general formula (2) include a glycidyl group, a glycidyloxy group, a glycidyloxycarbonyl group, a glycidylamino group, and an epoxycycloalkyl group (such as an epoxycyclopentyl group, an epoxycyclohexyl group, and an epoxycyclooctyl group), and among these, a glycidyloxy group is preferred.
Examples of the divalent linking group represented by L ¹ in the general formula (2) include an ether bond, a divalent linking group represented by the structural formula (1), a peroxy group, and an acetal group.
The divalent linking group represented by ^L2 and ^L3 in formula (2) includes a phenylene group, a naphthylene group, etc., with a phenylene group being preferred and a p-phenylene group being more preferred.
In the general formula (2), a1 and a2 are preferably integers of 0 to 2, and more preferably integers of 0 to 1.
In the general formula (2), n is preferably 1 to 3, more preferably 1 or 2, and further preferably 1.

In the case where the encapsulating composition does not contain a third epoxy resin described later, the epoxy group equivalent in the first epoxy resin is, for example, 180 g/eq or less. From the viewpoint of achieving both an improvement in thermal conductivity and suppression of an increase in the high-temperature elastic modulus, the epoxy group equivalent is preferably 130 g/eq to 180 g/eq, more preferably 135 g/eq to 175 g/eq, and even more preferably 140 g/eq to 170 g/eq.
Furthermore, when the encapsulating composition contains a third epoxy resin described later, the epoxy group equivalent in the mixture of the first epoxy resin and the third epoxy resin is, for example, 180 g/eq or less. From the viewpoint of achieving both an improvement in thermal conductivity and suppression of an increase in the high-temperature elastic modulus, the epoxy group equivalent is preferably 125 g/eq to 180 g/eq, more preferably 130 g/eq to 175 g/eq, and even more preferably 135 g/eq to 170 g/eq.
Here, the above-mentioned "epoxy group equivalent" is measured as follows. Specifically, the epoxy resin to be measured is weighed and dissolved in a solvent such as methyl ethyl ketone, and then acetic acid and a tetraethylammonium bromide acetate solution are added, followed by potentiometric titration with a perchloric acid/acetic acid standard solution. An indicator may be used in this titration.

When the sealing composition does not contain a third epoxy resin described later, the content of the first epoxy resin relative to the total amount of all epoxy resins contained in the sealing composition is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, from the viewpoint of both suppressing the increase in high-temperature elastic modulus and improving thermal conductivity. Also, when the sealing composition does not contain a third epoxy resin described later, the content of the first epoxy resin relative to the total amount of all epoxy resins contained in the sealing composition is preferably 70% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, from the viewpoint of moldability of the sealing composition. When the sealing composition does not contain a third epoxy resin described later, the content of the first epoxy resin relative to the total amount of all epoxy resins contained in the sealing composition is preferably 10% by mass to 70% by mass, more preferably 20% by mass to 50% by mass, and even more preferably 25% by mass to 40% by mass, from the viewpoint of suppressing the increase in high-temperature elastic modulus, improving thermal conductivity, and moldability of the sealing composition.

When the encapsulating composition contains a third epoxy resin described later, the total content of the first epoxy resin and the third epoxy resin relative to the total amount of all epoxy resins contained in the encapsulating composition is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, from the viewpoint of both suppressing an increase in the high-temperature elastic modulus and improving thermal conductivity. When the encapsulating composition contains a third epoxy resin described later, the total content of the first epoxy resin and the third epoxy resin relative to the total amount of all epoxy resins contained in the encapsulating composition is preferably 70% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, from the viewpoint of moldability of the encapsulating composition. When the encapsulating composition contains a third epoxy resin described later, the total content of the first epoxy resin and the third epoxy resin relative to the total amount of all epoxy resins contained in the encapsulating composition is preferably 10% by mass to 70% by mass, more preferably 20% by mass to 50% by mass, and even more preferably 25% by mass to 40% by mass, from the viewpoint of suppressing an increase in the high-temperature elastic modulus, improving thermal conductivity, and moldability of the encapsulating composition.
In addition, when the encapsulating composition contains a third epoxy resin described later, the content of the first epoxy resin relative to the total of the first epoxy resin and the third epoxy resin is, for example, 5 mass% to 35 mass%, and from the viewpoint of suppressing an increase in the high-temperature elastic modulus, is preferably 10 mass% to 35 mass%, and more preferably 20 mass% to 35 mass%.

When the sealing composition does not contain a third epoxy resin described later, the content of the first epoxy resin in the entire sealing composition is preferably 0.2 mass % to 3.0 mass %, more preferably 0.4 mass % to 1.5 mass %, and even more preferably 0.6 mass % to 1.1 mass %.
When the encapsulating composition contains a third epoxy resin described later, the total content of the first epoxy resin and the third epoxy resin in the entire encapsulating composition is preferably 0.2 mass% to 3.0 mass%, more preferably 0.4 mass% to 1.5 mass%, and even more preferably 0.6 mass% to 1.1 mass%.

(Second Epoxy Resin)
The second epoxy resin is not particularly limited as long as it is an epoxy resin other than the first epoxy resin and the third epoxy resin described below and has a melting point or softening point of 50° C. or higher.
Here, the melting point of the epoxy resin is a value measured by differential scanning calorimetry (DSC), and the softening point of the epoxy resin is a value measured by a method in accordance with JIS K 7234:1986 (ring and ball method).
From the viewpoint of moldability of the encapsulating composition, the melting point or softening point of the second epoxy resin is preferably 50° C. or higher, more preferably 60° C. or higher, and even more preferably 70° C. or higher. From the viewpoint of kneadability during production, the melting point or softening point of the second epoxy resin is preferably 150° C. or lower, more preferably 130° C. or lower, and even more preferably 120° C. or lower. From the viewpoint of moldability of the encapsulating composition and kneadability during production, the melting point or softening point of the second epoxy resin is preferably 50° C. to 150° C., more preferably 60° C. to 130° C., and even more preferably 70° C. to 120° C.

The epoxy group equivalent in the second epoxy resin is not particularly limited, but is preferably less than 300 g/eq, and from the viewpoint of achieving both moldability and suppression of an increase in the high-temperature elastic modulus, is more preferably 120 g/eq to 270 g/eq, and even more preferably 150 g/eq to 240 g/eq.

The second epoxy resin has at least two epoxy groups in one molecule. The number of epoxy groups in one molecule of the second epoxy resin is not particularly limited, and may be 2 to 8, preferably 2 to 6, more preferably 2 to 3, and particularly preferably 2.
The epoxy group may be contained in the molecule of the first epoxy resin as part of at least one group selected from a glycidyl group, a glycidyloxy group, a glycidyloxycarbonyl group, a glycidylamino group, an epoxycycloalkyl group (an epoxycyclopentyl group, an epoxycyclohexyl group, an epoxycyclooctyl group, etc.), and the like.

The second epoxy resin preferably has, in addition to two or more epoxy groups, a divalent linking group represented by the following general formula (3) in the molecule.
In the following general formula (3), * represents a bond, and R ¹ to R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aromatic group having 4 to 18 carbon atoms.

In the general formula (3), R ¹ to R ⁴ each independently represent preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a methyl group.
In addition, in the general formula (3), R ⁵ to R ⁸ each independently preferably represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group, and further preferably a hydrogen atom.

The content of the second epoxy resin relative to the total amount of all epoxy resins contained in the encapsulating composition is preferably 30% by mass to 90% by mass, more preferably 50% by mass to 80% by mass, and further preferably 60% by mass to 75% by mass, from the viewpoint of achieving both suppression of an increase in high-temperature elastic modulus and moldability.
Furthermore, the content of the second epoxy resin in the entire sealing composition is preferably 1.0 mass % to 5.0 mass %, more preferably 1.5 mass % to 4.0 mass %, and even more preferably 1.7 mass % to 3.0 mass %.

(Third Epoxy Resin)
The third epoxy resin is not particularly limited as long as it is a resin other than the first epoxy resin, has a benzene ring and at least two epoxy groups bonded to the para-position of the benzene ring directly or via a linking group, and the benzene ring does not have substituents at the ortho- and meta-positions of the bonding positions of the two epoxy groups.

The number of benzene rings that the third epoxy resin has in one molecule is not particularly limited, and may be in the range of 1 to 3, preferably 1 to 2, and more preferably 1.
When the third epoxy resin has two or more benzene rings, it is preferable that each of the two or more benzene rings is substituted only at the para position (that is, has no substituents at the ortho and meta positions).
The third epoxy resin may further have an aromatic hydrocarbon ring other than a benzene ring.

The number of epoxy groups in one molecule of the third epoxy resin is not particularly limited as long as it is two or more, and two is preferred.
The epoxy group may be contained in the molecule of the third epoxy resin as a part of at least one group selected from a glycidyl group, a glycidyloxy group, a glycidyloxycarbonyl group, a glycidylamino group, an epoxycycloalkyl group (an epoxycyclopentyl group, an epoxycyclohexyl group, an epoxycyclooctyl group, etc.), and the like.
Among them, the third epoxy resin preferably has a glycidyloxy group in the molecule, more preferably has a glycidyloxy group directly bonded to a benzene ring in the molecule, and when the third epoxy resin has two or more glycidyloxy groups, it is preferable that all of the two or more glycidyloxy groups are directly bonded to a benzene ring.

An example of the third epoxy resin is an epoxy resin represented by the following general formula (4).

In the above general formula (4), ^E1 , ^E2 , and ^L2 respectively represent the same groups as ^E1 , ^E2 , and ^L2 in the above general formula (2). Also, in the above general formula (4), a1 represents the same number as a1 in the above general formula (2).

The total epoxy resin content in the sealing composition is preferably 2.0% by mass to 6% by mass, more preferably 3.0% by mass to 5.5% by mass, and even more preferably 3.0% by mass to 5.0% by mass.
The content of the total epoxy resin in the sealing composition excluding the inorganic filler is preferably 40% by mass to 70% by mass, more preferably 45% by mass to 64% by mass, and further preferably 48% by mass to 55% by mass.

- 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.
Examples of the curing agent include a phenol curing agent, an amine curing agent, an acid anhydride curing agent, a polymercaptan curing agent, a polyaminoamide curing agent, an isocyanate curing agent, and a blocked isocyanate curing agent. From the viewpoint of obtaining a sealing composition that has excellent reflow resistance while maintaining fluidity, the curing agent is preferably a phenol curing agent, an amine curing agent, or an acid anhydride curing agent, and more preferably a phenol curing agent. The curing agent may be used alone or in combination of two or more types.

Examples of phenolic hardeners include phenolic resins and polyhydric phenolic compounds having two or more phenolic hydroxyl groups in one molecule. Specifically, polyhydric phenolic compounds such as resorcin, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted biphenols; novolak-type phenolic resins obtained by condensing or co-condensing at least one phenolic compound selected from the group consisting of phenolic compounds such as phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol, and naphthol compounds such as α-naphthol, β-naphthol, and dihydroxynaphthalene, with an aldehyde compound such as formaldehyde, acetaldehyde, or propionaldehyde, under an acid catalyst; aralkyl phenols synthesized from the above-mentioned phenolic compounds and dimethoxy-para-xylene, bis(methoxymethyl)biphenyl, or the like. Examples of the phenolic resins include phenol aralkyl resins, naphthol aralkyl resins, etc.; paraxylylene-modified phenolic resins; metaxylylene-modified phenolic resins; melamine-modified phenolic resins; terpene-modified phenolic resins; dicyclopentadiene-type phenolic resins and dicyclopentadiene-type naphthol resins synthesized by copolymerization of the above-mentioned phenolic compounds with dicyclopentadiene; cyclopentadiene-modified phenolic resins; polycyclic aromatic ring-modified phenolic resins; biphenyl-type phenolic resins; triphenylmethane-type phenolic resins obtained by condensing or co-condensing the above-mentioned phenolic compounds with aromatic aldehyde compounds such as benzaldehyde and salicylaldehyde under an acid catalyst; and phenolic resins obtained by copolymerizing two or more of these. These phenolic resins and polyhydric phenolic compounds may be used alone or in combination of two or more.

Of these, the phenolic hardener is preferably a multifunctional phenolic resin, of which novolac-type phenolic resin, aralkyl-type phenolic resin, and triphenylmethane-type phenolic resin are preferred, with triphenylmethane-type phenolic resin being more preferred.

Examples of triphenylmethane type phenolic resins include phenolic resins represented by the following general formula (5).

In the above general formula (5), R ¹¹ to R ¹⁵ each independently represent a monovalent organic group having 1 to 18 carbon atoms, b1 and b2 each independently represent an integer of 0 to 4, b3 each independently represent an integer of 0 to 3, b4 and b5 each independently represent an integer of 0 to 4, and n represents 0 to 10.

Examples of the monovalent organic group having 1 to 18 carbon atoms represented by R ¹¹ to R ¹⁵ in general formula (5) include a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted aralkyl group.
In the general formula (5), b1 to b5 are preferably integers of 0 to 1, and more preferably 0.
In the general formula (5), n is preferably 1 to 7, and more preferably 2 to 5.

The functional group equivalent of the curing agent is not particularly limited, and from the viewpoint of moldability, it is preferably 70 g/eq to 500 g/eq, more preferably 70 g/eq to 300 g/eq, and even more preferably 80 g/eq to 250 g/eq. The functional group equivalent is a value measured in accordance with JIS K0070:1992.

When the curing agent is a solid, its softening point or melting point is not particularly limited. From the viewpoints of moldability and reflow resistance, the softening point or melting point is preferably 40° C. to 180° C., and from the viewpoint of handleability during production of the encapsulating composition, the softening point or melting point is more preferably 50° C. to 130° C., and further preferably 55° C. to 100° C.
The melting point or softening point of the curing agent is a value measured in the same manner as the melting point or softening point of the epoxy resin.

With regard to the compounding ratio of epoxy resin to hardener, from the viewpoint of minimizing the amount of unreacted components of each, it is preferable that the hardener is compounded so that the equivalent of the functional group of the hardener (e.g., phenolic hydroxyl group in the case of phenolic resin) is 0.5 to 1.5 equivalents per equivalent of epoxy group of the epoxy resin, and it is particularly preferable that the hardener is compounded so that the equivalent is 0.7 to 1.2 equivalents.

- Inorganic filler -
The inorganic fillers may be used alone or in combination of two or more kinds.
In the case of using two or more kinds of inorganic fillers in combination, there can be mentioned the case of using two or more kinds of inorganic fillers different in components, average particle size, shape, etc.
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.

The inorganic filler preferably contains alumina from the viewpoint of high thermal conductivity. The inorganic filler may be entirely alumina or may be a combination of alumina and other inorganic fillers.
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, zirconia, etc. Furthermore, inorganic fillers having a flame retardant effect include aluminum hydroxide, zinc borate, etc.

When alumina and other inorganic fillers are used in combination as the inorganic filler, it is preferable to use silica as the other inorganic filler from the viewpoint of flowability.
When alumina and silica are used in combination as the inorganic filler, the content of alumina in the inorganic filler is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 85% by mass or more, and particularly preferably 95% by mass or more. The content of alumina in the inorganic filler may be 99.6% by mass or less.

The content of the inorganic filler is preferably 60 vol. % or more, more preferably 70 vol. % or more, and even more preferably 75 vol. % or more, based on the entire sealing composition, from the viewpoints of moisture absorption, reduction of the linear expansion coefficient, improvement of strength, and solder heat resistance.
Moreover, from the viewpoint of high thermal conductivity, the content of the inorganic filler is particularly preferably 78% by volume or more, and extremely preferably 80% by volume or more, based on the entire sealing composition. From the viewpoint of moldability and flowability of the sealing composition, the content of the inorganic filler is preferably 95% by volume or less, more preferably 90% by volume or less, and even more preferably 85% by volume or less, based on the entire sealing composition. From the viewpoint of achieving both high thermal conductivity and moldability and flowability of the sealing composition, the content of the inorganic filler is preferably 78% by volume to 90% by volume, more preferably 78% by volume to 85% by volume, and even more preferably 80% by volume to 85% by volume.

The average particle size of the inorganic filler is preferably 4 μm to 100 μm, more preferably 7 μm to 70 μm, and even more preferably 7 μm to 40 μm. In the present disclosure, the average particle size of the inorganic filler refers to the average particle size of alumina when alumina is used alone as the inorganic filler, and refers to the average particle size of the inorganic filler as a whole when alumina is used in combination with other inorganic fillers as the inorganic filler.
The thermal conductivity of the cured product of the sealing composition tends to increase as the average particle size of the inorganic filler increases.
The average particle size of the inorganic filler can be measured by the following method.

The inorganic filler to be measured is added to the solvent (pure water) in the range of 1% to 5% by mass together with 1% to 8% by mass of a surfactant, and the mixture is vibrated for 30 seconds to 5 minutes in a 110W ultrasonic cleaner to disperse the inorganic filler. Approximately 3 mL of the dispersion is poured into a measurement cell and measured at 25°C. A laser diffraction particle size distribution analyzer (HORIBA, Ltd., LA920) is used as the measurement device to measure the volumetric particle size distribution. The average particle size is determined as the particle size (D50%) when the cumulative amount from the small diameter side in the volumetric particle size distribution is 50%. The refractive index is that of alumina. When the inorganic filler is a mixture of alumina and other inorganic fillers, the refractive index of alumina is used.

From the viewpoints of fluidity and moldability, the specific surface area of the inorganic filler is preferably 0.7 ^{m 2} /g to 4.0 m ² /g, more preferably 0.9 m ² /g to 3.0 m ² /g, and even more preferably 1.0 ^m 2 /g to 2.5 m ² /g.
The fluidity of the sealing composition tends to increase as the specific surface area of the inorganic filler decreases.
In the present disclosure, the specific surface area of an inorganic filler refers to the specific surface area of alumina when, for example, alumina is used alone as the inorganic filler, and refers to the specific surface area of a mixture of inorganic fillers when alumina is used in combination with other inorganic fillers as the inorganic filler.
The specific surface area (BET specific surface area) of the inorganic filler can be measured from the nitrogen adsorption capacity in accordance with JIS Z 8830: 2013. As an evaluation device, AUTOSORB-1 (product name) manufactured by QUANTACROME can be used. When measuring the BET specific surface area, it is preferable to first perform a pretreatment to remove moisture by heating, since it is considered that moisture adsorbed on the sample surface and in the structure affects the gas adsorption capacity.
In the pretreatment, a measurement cell containing 0.05 g of a measurement sample is depressurized to 10 Pa or less using a vacuum pump, heated to 110° C., and held for 3 hours or more, and then naturally cooled to room temperature (25° C.) while maintaining the depressurized state. After this pretreatment, the evaluation temperature is set to 77 K, and the evaluation pressure range is set to less than 1 in terms of relative pressure (equilibrium pressure with respect to the saturated vapor pressure).

-Other ingredients-
(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.
Specific examples of the curing accelerator include 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 containing maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, and 2,3-dimethoxy-5-methyl-1 quinone compounds such as phenyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, and phenyl-1,4-benzoquinone; compounds having intramolecular polarization obtained by adding compounds having a π bond 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 Examples of the curing accelerator include imidazole compounds such as 4-methylimidazole, 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 a compound having a π bond such as maleic anhydride, the above-mentioned quinone compound, diazophenylmethane, and phenolic resin to an organic phosphine compound, tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, 2-ethyl-4-methylimidazole tetraphenylborate, and N-methylmorpholine tetraphenylborate, derivatives of tetraphenylboron salts, and adducts of phosphine compounds such as triphenylphosphonium-triphenylborane and N-methylmorpholine tetraphenylphosphonium-tetraphenylborate with tetraphenylboron salts. One type of curing accelerator may be used alone, or two or more types may be used in combination.

Of these, the curing accelerator is preferably a phosphorus-based curing accelerator, of which organic phosphine compounds, adducts of organic phosphine compounds, and adducts of phosphine compounds and tetraphenylboron salts are more preferred, organic phosphine compounds and adducts of organic phosphine compounds are even more preferred, and compounds formed by the addition of a quinone compound to an organic phosphine compound are particularly preferred.

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

(Ion trapping agent)
The sealing composition may further include 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 that is generally used in sealing materials used in the manufacture of semiconductor devices. Examples of the ion trapping agent include compounds represented by the following general formula (6) or the following general formula (7).

Mg _1-a Al _a (OH) ₂ (CO ₃ ) _a/2・uH ₂ O (6)
(In the general formula (6), a is 0<a≦0.5, and u is a positive number.)
BiO _b (OH) _c (NO ₃ ) _d (7)
(In the general formula (7), b is 0.9≦b≦1.1, c is 0.6≦c≦0.8, and d is 0.2≦d≦0.4.)

Ion trapping agents are commercially available. An example of a compound represented by general formula (6) is "DHT-4A" (Kyowa Chemical Industry Co., Ltd., product name). An example of a compound represented by general formula (7) is "IXE500" (Toagosei Co., Ltd., product name).

Other examples of ion trapping agents include hydrous oxides of elements selected from magnesium, aluminum, titanium, zirconium, antimony, and the like.
The ion trapping agent may be used alone or in combination of two or more kinds.

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 epoxy resin from the viewpoint of realizing sufficient moisture resistance reliability. From the viewpoint of fully exerting the effects of other components, the content of the ion trapping agent is preferably 15 parts by mass or less per 100 parts by mass of epoxy resin.

The average particle size of the ion trapping agent is preferably 0.1 μm to 3.0 μm, and the maximum particle size is preferably 10 μm or less. The average particle size of the ion trapping agent can be measured in the same manner as for the inorganic filler.

(Coupling Agent)
The sealing composition may further contain a coupling agent. The type of the coupling agent is not particularly limited, and any known coupling agent may 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.

Silane coupling agents include vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, 8-methacryloxyoctyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-[bis(β-hydroxyethyl)]aminopropyltriethoxysilane, N-β-(aminoethyl)-γ N-aminopropyltrimethoxysilane, 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.

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.

-Specific silane compounds-
The sealing composition may contain, as the coupling agent, a silane compound having a structure in which a chain hydrocarbon group having 6 or more carbon atoms is bonded to a silicon atom (hereinafter, also referred to as a "specific silane compound").
The chain hydrocarbon group may be branched or may have a substituent. In the present disclosure, the carbon number of the chain hydrocarbon group means the carbon number not including the carbon of the branch or the substituent. The chain hydrocarbon group may or may not contain an unsaturated bond, and preferably does not contain an unsaturated bond.

The number of chain hydrocarbon groups bonded to the silicon atom in the specific silane compound may be 1 to 4, preferably 1 to 3, more preferably 1 or 2, and even more preferably 1.

When the number of linear hydrocarbon groups bonded to the silicon atom in the specific silane compound is 1 to 3, the atoms or atomic groups other than the linear hydrocarbon groups bonded to the silicon atom are not particularly limited and may each independently be a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group, an aryl group, an aryloxy group, etc. Among these, it is preferable that one or more alkoxy groups are bonded to the linear hydrocarbon group in addition to the linear hydrocarbon group, and it is more preferable that one linear hydrocarbon group and three alkoxy groups are bonded to the silicon atom.

The carbon number of the chain hydrocarbon group of the specific silane compound is 6 or more, and from the viewpoint of suppressing viscosity, it is preferably 7 or more, and more preferably 8 or more. There is no particular limit to the upper limit of the carbon number of the chain hydrocarbon group of the specific silane compound, and from the viewpoint of dispersibility in resin, balance of physical properties of the cured product, etc., it is preferably 12 or less, more preferably 11 or less, and even more preferably 10 or less.

When the chain hydrocarbon group has a substituent, the substituent is not particularly limited. The substituent may be present at the end of the chain hydrocarbon group or on a side chain of the chain hydrocarbon group.

The linear hydrocarbon group preferably has at least one functional group (hereinafter also referred to as a specific functional group) selected from a (meth)acryloyl group, an epoxy group, and an alkoxy group, more preferably has at least one functional group selected from a (meth)acryloyl group and an epoxy group, and even more preferably has a (meth)acryloyl group. The specific functional group may be present at the end of the linear hydrocarbon group, or may be present in a side chain of the linear hydrocarbon group. From the viewpoint of suppressing viscosity, it is preferable that the specific functional group is present at the end of the linear hydrocarbon group.

When the chain hydrocarbon group has a (meth)acryloyl group, the (meth)acryloyl group may be directly bonded to the chain hydrocarbon group, or may be bonded via another atom or atomic group. For example, the chain hydrocarbon group may have a (meth)acryloyloxy group. In particular, it is preferable that the chain hydrocarbon group has a methacryloyloxy group.

When the chain hydrocarbon group has an epoxy group, the epoxy group may be directly bonded to the chain hydrocarbon group, or may be bonded via another atom or atomic group. For example, the chain hydrocarbon group may have a glycidyloxy group, an alicyclic epoxy group, or the like. In particular, it is preferable that the chain hydrocarbon group has a glycidyloxy group.

When the chain hydrocarbon group has an alkoxy group, the alkoxy group may be directly bonded to the chain hydrocarbon group or may be bonded via another atom or atomic group, and is preferably directly bonded to the chain hydrocarbon group. The alkoxy group is not particularly limited and may be a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, or the like. In particular, from the viewpoint of availability, it is preferable that the chain hydrocarbon group has a methoxy group.

In the specific silane compound, the equivalent weight (molecular weight/number of functional groups) of at least one functional group selected from a (meth)acryloyl group, an epoxy group, and an alkoxy group is not particularly limited. From the viewpoint of reducing the viscosity of the sealing composition, it is preferably 200 g/eq to 420 g/eq, more preferably 210 g/eq to 405 g/eq, and even more preferably 230 g/eq to 390 g/eq.

Examples of specific silane compounds include hexyltrimethoxysilane, heptyltrimethoxysilane, octyltrimethoxysilane, hexyltriethoxysilane, heptyltriethoxysilane, octyltriethoxysilane, 6-glycidoxyhexyltrimethoxysilane, 7-glycidoxyheptyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, 6-(meth)acryloxyhexyltrimethoxysilane, 7-(meth)acryloxyheptyltrimethoxysilane, 8-(meth)acryloxyoctyltrimethoxysilane, and decyltrimethoxysilane. Among these, from the viewpoint of reducing the viscosity of the sealing composition, 8-glycidoxyoctyltrimethoxysilane and 8-methacryloxyoctyltrimethoxysilane are preferred. The specific silane compounds may be used alone or in combination of two or more.

The specific silane compound may be synthesized, or a commercially available product may be used. Commercially available specific silane compounds include KBM-3063 (hexyltrimethoxysilane), KBE-3063 (hexyltriethoxysilane), KBE-3083 (octyltriethoxysilane), KBM-4803 (8-glycidoxyoctyltrimethoxysilane), KBM-5803 (8-methacryloxyoctyltrimethoxysilane), and KBM-3103C (decyltrimethoxysilane), all manufactured by Shin-Etsu Chemical Co., Ltd.

When the sealing composition contains a coupling agent, the content of the coupling agent is preferably 3 mass % or less, more preferably 2 mass % or less, and even more preferably 1 mass % or less, based on the total amount of the sealing composition. From the viewpoint of exerting its effect, the content of the coupling agent is preferably 0.1 mass % or more, more preferably 0.15 mass % or more, and even more preferably 0.2 mass % or more.
The content of the coupling agent may be 0.01 parts by mass or more, or 0.02 parts by mass or more, relative to 100 parts by mass of the inorganic filler. The content of the coupling agent is preferably 5 parts by mass or less, and more preferably 2.5 parts by mass or less, relative to 100 parts by mass of the inorganic filler. From the viewpoint of achieving both flowability and moldability of the package, the content of the coupling agent is preferably 0.05 parts by mass to 2.0 parts by mass, more preferably 0.1 parts by mass to 1.5 parts by mass, and even more preferably 0.2 parts by mass to 1.0 parts by mass, relative to 100 parts by mass of the inorganic filler.

(Release Agent)
The sealing composition may further contain a release agent. The type of the release agent is not particularly limited, and a known release agent may be used. Specific examples include higher fatty acids, carnauba wax, montan wax, and polyethylene wax. The release agent may be used alone or in combination of two or more types.
When the sealing composition contains a release agent, the content of the release agent is preferably 10 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 mass % or more.

(Colorants and Modifiers)
The encapsulating composition may contain a colorant (carbon black, etc.). The encapsulating composition may also contain a modifier (silicone, silicone rubber, etc.). The colorant and modifier may each be used alone or in combination of two or more kinds.

When conductive particles such as carbon black are used as the colorant, the conductive particles preferably have a content of particles having a particle diameter of 10 μm or more of 1 mass % or less.
When the sealing composition contains conductive particles, the content of the conductive particles is preferably 3 mass % or less based on the total amount of the epoxy resin and the curing agent.

(Other additives)
The sealing composition may further contain other additives, if necessary.
Other additives include flame retardants, anion exchangers, plasticizers, etc. Furthermore, various additives well known in the art may be added to the composition as necessary.

<Method of producing sealing composition>
The method for producing the sealing composition is not particularly limited, and can be performed by a known method. For example, a mixture of raw materials in a predetermined amount is thoroughly mixed by a mixer or the like, and then kneaded by a hot roll, an extruder, or the like, and then cooled, crushed, or the like to produce the sealing composition. The state of the sealing composition is not particularly limited, and may be a powder, solid, liquid, or the like.

<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.

The method for encapsulating a semiconductor element using the encapsulating composition is not particularly limited, and any known method can be applied. The transfer molding method is common, but compression molding, injection molding, compression molding, etc. may also be used.

The semiconductor device disclosed herein is suitable as an IC (Integrated Circuit), an LSI (Large-Scale Integration), etc.

Examples of the present invention are described below, but the present invention is not limited thereto. In addition, the numerical values in the table mean "parts by mass" unless otherwise specified.

<Examples 1 to 6 and Comparative Examples 1 to 2>
The components shown below were premixed (dry blended) in the mixing ratios (parts by mass) shown in Table 1, then kneaded in a twin-axis kneader, cooled and pulverized to produce a powdered sealing composition.
The details of the components shown in Table 1 are as follows.

(A) Epoxy Resin Epoxy resin A1-1: First epoxy resin, an epoxy resin represented by the general formula (2) ( ^E1 and ^E2 are both glycidyloxy groups, ^L1 is an ether bond, a1 and a2 are both 0, and n is 1), epoxy group equivalent "165 g/eq", melting point "83°C"
Epoxy resin A1-2: a mixture of a first epoxy resin and a third epoxy resin, a mixture of an epoxy resin represented by the general formula (2) ( ^E1 and ^E2 are both glycidyloxy groups, ^L1 is a linking group represented by the structural formula (1), ^L2 and ^L3 are both p-phenylene groups, a1 and a2 are both 0 or 1, n is 1) and an epoxy resin represented by the general formula (4) ( ^E1 and ^E2 are both glycidyloxy groups, ^L2 is a p-phenylene group, a1 is 0 or 1), epoxy group equivalent "140 g/eq"
Epoxy resin A2-1: Second epoxy resin, Mitsubishi Chemical Corporation, product name "YX4000H", epoxy group equivalent "192 g/eq", softening point "107°C", biphenyl type epoxy resin Epoxy resin A2-2: Second epoxy resin, Nippon Steel Chemical & Material Corporation, product name "YSLV-70XY", epoxy group equivalent "192 g/eq", melting point "67°C", bisphenol type epoxy resin

(B) Hardener Phenolic resin B1: Triphenylmethane type phenolic resin, Air Water Inc., product name "HE910-09", hydroxyl equivalent "92 to 104 g/eq", softening point "75 to 85° C."

(C) Curing Accelerator Curing Accelerator C1: Phosphorus-based curing accelerator (adduct of tributylphosphine and benzoquinone)
(D) Coupling Agent Coupling Agent D1: 8-methacryloxyoctyltrimethoxysilane, Shin-Etsu Chemical Co., Ltd., product name "KBM-5803"
(E) Release Agent Release Agent E1: Montan wax, Clariant, product name "HW-E"
(F) Colorant Pigment F1: Carbon black, Mitsubishi Chemical Corporation, product name "MA600"
(G) Additives Additive G1: Triphenylphosphine oxide, Hokko Chemical Industry Co., Ltd., product name "TP-50"
(H) Modifier Modifier H1: Silicone, Toray Dow Corning Co., Ltd., product name "BY16-876"

(I) Inorganic Filler Filler I1: Silica particles, Tokuyama Corporation, product name "CP-102", spherical, specific surface area "190 m ² /g to 230 m ² /g"
Filler I2: Alumina particles, Admatechs Co., Ltd., product name "AE2000", spherical, average particle size "0.7 μm"
Filler I3: Alumina particles, Denka Co., Ltd., product name "DAB10SITS1", spherical, average particle size "10 μm"

-evaluation-
The properties of the sealing compositions prepared in the examples and comparative examples were evaluated by the following property tests. The evaluation results are shown in Table 1 below.

(High temperature elastic modulus)
Using the encapsulating composition obtained above, a test piece having a size of 127 mm x 12.7 mm x 4 mm was produced by a transfer molding machine under the conditions of a mold temperature of 175 ° C, a molding pressure of 6.9 MPa, and a curing time of 90 seconds. Then, post-curing was performed at 175 ° C for 6 hours. Using a Tensilon (A & D Co., Ltd.) as an evaluation device, a three-point support bending test in accordance with JIS-K-7171 (2016) was performed at 260 ° C to determine the bending modulus of the test piece.
The flexural modulus E is defined by the following formula, and the flexural modulus obtained by measurement at 260° C. is taken as the “high temperature modulus”.
In the following formula, E is the flexural modulus (MPa), P is the load cell value (N), y is the displacement (mm), l is the span = 64 mm, w is the test piece width = 12.7 mm, and h is the test piece thickness = 4 mm.

(Thermal Conductivity)
Using the encapsulating composition obtained above, a transfer molding machine was used to prepare a test piece for evaluating thermal conductivity under the conditions of a mold temperature of 175°C to 180°C, a molding pressure of 7 MPa, and a curing time of 300 seconds. Next, the thermal diffusivity in the thickness direction of the molded test piece was measured. The thermal diffusivity was measured by a laser flash method (apparatus: LFA467 nanoflash, NETZSCH). Pulse light irradiation was performed under conditions of a pulse width of 0.31 (ms) and an applied voltage of 247 V. The measurement was performed at an ambient temperature of 25°C ± 1°C. The density of the test piece was measured using an electronic specific gravity meter (AUX220, Shimadzu Corporation). The specific heat was calculated from the theoretical specific heat of the encapsulating composition calculated from the literature values of the specific heat of each material and the blending ratio.
The thermal conductivity value was then obtained by multiplying the thermal diffusivity by the specific heat and density using equation (8).
λ=α×Cp×ρ...Formula (8)
(In formula (8), λ is thermal conductivity (W/(m·K)), α is thermal diffusivity (m ² /s), Cp is specific heat (J/(kg·K)), and ρ is density (kg/m ³ ).)

As is clear from the evaluation results in Table 1, the sealing compositions of Examples 1 to 6, which contain the first epoxy resin, give cured products with higher thermal conductivity than the sealing compositions of Comparative Examples 1 and 2, which do not contain the first epoxy resin. Furthermore, the high-temperature elastic modulus of the cured products of the sealing compositions of Examples 1 to 6 is equivalent to the high-temperature elastic modulus of the cured products of the sealing compositions of Comparative Examples 1 and 2. In other words, it can be seen that the sealing compositions of Examples 1 to 6 have improved thermal conductivity in the cured products while keeping the high-temperature elastic modulus of the cured products low, compared to the sealing compositions of Comparative Examples 1 and 2.

The disclosure of Japanese Patent Application No. 2019-035227 is incorporated by reference in its entirety into this disclosure.
All publications, patent applications, and standards in this disclosure are incorporated by reference into this disclosure to the same extent as if each individual publication, patent application, or standard was specifically and individually indicated to be incorporated by reference.

Claims (6)

a first epoxy resin having, in its molecule, at least two benzene rings and at least one ether bond connecting the two benzene rings directly or via a linking group, the two benzene rings having no substituents at the ortho- and meta-positions relative to the bonding positions of the ether bonds;
An epoxy resin represented by the following general formula (4),
A hardener;
An inorganic filler;
Contains
The inorganic filler contains alumina and silica, and the content of alumina in the inorganic filler is 50 mass% or more;
The encapsulating composition, wherein the first epoxy resin comprises an epoxy resin represented by the following general formula (2):


(In general formula (2), ^E1 and ^E2 each independently represent a monovalent group containing an epoxy group, ^L1 represents a divalent linking group represented by the following structural formula (1) , ^L2 and ^L3 each independently represent an aromatic hydrocarbon ring , a1 and a2 each represent 0 or 1 and are a mixture thereof, and n represents an integer of 1 to 2. )

(In the above structural formula (1), * indicates the bond to the benzene ring.)

(In general formula (4), E1 ^and E2 ^each independently represent a monovalent group containing an epoxy group, L2 ^represents an aromatic hydrocarbon ring, and a1 represents 0 or 1.) The sealing composition according to claim 1, wherein the content of the inorganic filler is 78% by volume or more relative to the entire sealing composition. The sealing composition according to claim 1 or 2, further comprising a second epoxy resin having a melting point or softening point of 50°C or higher. The sealing composition according to claim 3, wherein the content of the second epoxy resin is 80 mass% or less based on the total amount of epoxy resins contained in the sealing composition. The sealing composition according to claim 3 or 4, wherein the content of the second epoxy resin is 50 mass% or more based on the total amount of the epoxy resins contained in the sealing composition. A semiconductor device comprising: a semiconductor element; and a cured product of the sealing composition according to any one of claims 1 to 5, which seals the semiconductor element.