WO2020130097A1

WO2020130097A1 - Sealing composition and semiconductor device

Info

Publication number: WO2020130097A1
Application number: PCT/JP2019/049923
Authority: WO
Inventors: 実佳田中; 健太石橋; 拓也児玉; 慧地堀
Original assignee: 日立化成株式会社
Priority date: 2018-12-21
Filing date: 2019-12-19
Publication date: 2020-06-25
Also published as: JP7392659B2; TW202033726A; CN113242873B; JPWO2020130097A1; CN113242873A

Abstract

This sealing composition contains: a first epoxy resin having an epoxy group equivalent of 300 g/eq or greater and a glass transition temperature of 40°C or lower when cured using a polyfunctional phenol resin curing agent and a phosphorus curing promoter; a curing agent; and an inorganic filler.

Description

Sealing composition and semiconductor device

The present disclosure relates to a sealing composition and a semiconductor device.

In recent years, with the miniaturization and high integration, there is concern about heat generation inside the semiconductor package. High heat conductivity is required for members used for the semiconductor package because heat generation may cause a deterioration in performance of an electric component or an electronic component having the semiconductor package. Therefore, it is required that the sealing material of the semiconductor package has high thermal conductivity.
On the other hand, members used for semiconductor packages are also required to have durability against a temperature cycle test.
For example, if the inorganic filler is highly filled, the thermal conductivity of the encapsulant can be increased, but the durability of the encapsulant may decrease due to the high elastic modulus. There is a trade-off relationship between low elasticity and low elasticity. Therefore, it may be difficult to achieve both high thermal conductivity and low elastic modulus.

As an example of the encapsulant highly filled with the inorganic filler, a semiconductor encapsulation in which (A) an epoxy resin, (B) a curing agent, and (D) an inorganic filler containing spherical alumina and spherical silica are essential components An epoxy resin composition for use, wherein the spherical alumina is (d1) a first spherical alumina having an average particle diameter of 40 μm or more and 70 μm or less, and (d2) a second spherical alumina having an average particle diameter of 10 μm or more and 15 μm or less. And the spherical silica includes (d3) a first spherical silica having an average particle diameter of 4 μm or more and 8 μm or less and (d4) a second spherical silica having an average particle diameter of 0.05 μm or more and 1.0 μm or less. The total amount of (d3)+(d4) is 17% or more and 23% or less with respect to the total inorganic filler, and the ratio of (d3)/(d4) is (d3)/(d4)=1. /8 or more and 5/4 or less, and an epoxy resin composition for semiconductor encapsulation, which is characterized in that the amount of the inorganic filler is 85 to 95% by mass in the total resin composition, is known (for example, Patent Document 1). 1)

Patent Document 1: Japanese Patent Laid-Open No. 2006-273920

However, in the epoxy resin composition for semiconductor encapsulation described in Patent Document 1, by highly filling alumina, which is a high thermal conductive filler, a sealing material (that is, a cured product of the epoxy resin composition for semiconductor encapsulation) is obtained. The elastic modulus may increase. Therefore, the development of a high thermal conductive encapsulant having a low elastic modulus is a challenge.

According to one embodiment of the present invention, a sealing composition and a sealing composition which can obtain a cured product having a high elastic modulus at room temperature (ie, 25°C) and a low elastic modulus at high temperature (ie, 260°C) while obtaining high thermal conductivity. A semiconductor device using the antistatic composition is provided.

The present invention includes the following embodiments.
<1>
A first epoxy resin having an epoxy group equivalent of 300 g/eq or more and having a glass transition temperature of 40° C. or less when cured using a polyfunctional phenol resin curing agent and a phosphorus-based curing accelerator;
A curing agent,
An inorganic filler,
A sealing composition containing:
<2>
The content rate of the said inorganic filler is a sealing composition as described in <1> which is 78 volume% or more with respect to the whole sealing composition.
<3>
The encapsulating composition according to <1> or <2>, further containing a second epoxy resin having a melting point or a softening point of 50° C. or higher.
<4>
The encapsulating composition according to any one of <1> to <3>, in which the content of the first epoxy resin is 20% by mass or more based on the total amount of the epoxy resins contained in the encapsulating composition. Stuff.
<5>
The encapsulating composition according to any one of <1> to <4>, in which the content of the first epoxy resin is 50% by mass or less based on the total amount of the epoxy resin contained in the encapsulating composition. Stuff.
<6>
The first epoxy resin is the encapsulating composition as described in any one of <1> to <5>, which has two epoxy groups in the molecule.
<7>
The sealing composition according to any one of <1> to <6>, wherein the first epoxy resin has a divalent linking group represented by the following structural formula (1) in the molecule.

In the above structural formula (1), * indicates a binding part.
<8>
A semiconductor device comprising: a semiconductor element; and a cured product of the encapsulating composition according to any one of <1> to <7>, which is obtained by encapsulating the semiconductor element.

Hereinafter, modes for carrying out the encapsulating composition and the semiconductor device of the present disclosure will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the constituent elements (including element steps and the like) are not essential unless otherwise specified. The same applies to numerical values and ranges thereof, and does not limit the present invention.

In the present disclosure, the numerical ranges indicated by using “to” include the numerical values before and after “to” as the minimum value and the maximum value, respectively.
In the numerical ranges described stepwise in the present disclosure, the upper limit or the lower limit described in one numerical range may be replaced with the upper limit or the lower limit of the numerical range described in other stages. .. Further, in the numerical range described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.
In the present disclosure, each component may include a plurality of types of corresponding substances. When there are multiple types of substances corresponding to each component in the composition, the content rate or content of each component is the total content rate or content of the multiple types of substances present in the composition unless otherwise specified. Means quantity.
In the present disclosure, a plurality of types of particles corresponding to each component may be included. When a plurality of types of particles corresponding to each component are present in the composition, the particle size of each component means a value for a mixture of the plurality of types of particles present in the composition unless otherwise specified.

<Sealing composition>
The sealing composition of the present disclosure has an epoxy group equivalent of 300 g/eq or more, and a glass transition temperature of 40° C. or less when cured using a polyfunctional phenol resin curing agent and a phosphorus-based curing accelerator. 1 epoxy resin, a curing agent, and an inorganic filler.
Since the encapsulating composition of the present disclosure contains the first epoxy resin described above, while obtaining high thermal conductivity, the elastic modulus at room temperature (that is, 25° C.) (hereinafter also referred to as “room temperature elastic modulus”) and the high temperature ( That is, a cured product having a low elastic modulus at 260° C. (hereinafter also referred to as “high temperature elastic modulus”) can be obtained.
Here, the "multifunctional phenol resin curing agent" is a curing agent that is a phenol resin having three or more functional groups (that is, hydroxyl groups) in one molecule, and the "phosphorus curing accelerator" is a curing accelerator having a phosphorus atom. Is.

The above "glass transition temperature when cured using a polyfunctional phenol resin curing agent and a phosphorus-based curing accelerator" is measured as follows.
First, a mixture of an epoxy resin to be measured, a triphenylmethane type phenolic resin which is a polyfunctional phenolic resin curing agent, and a quinone adduct of an organic phosphine compound which is a phosphorus-based curing accelerator is mixed at 175°C. A cured product for measurement is obtained by heating for 6 hours. The polyfunctional phenol resin curing agent is added so that the number of epoxy groups (that is, the total number) of the epoxy resin that is the measurement target and the number of hydroxyl groups (that is, the total number) of the phenol resin are approximately the same. Further, the phosphorus-based curing accelerator is added such that the content of the phosphorus-based curing accelerator is 3 parts by mass to 6 parts by mass with respect to 100 parts by mass in total of the epoxy resin and the polyfunctional phenol resin curing agent.
Next, the obtained cured product for measurement is cut, 10 mg is weighed, and DSC (Differential scanning calorimetry) measurement is performed. Specifically, a differential scanning calorimeter (TA Instruments Japan Co., Ltd., product name “DSC Q100”) was used to measure the temperature rise rate of 10° C./min, and the obtained chart was changed. The intersection of the tangents before and after the bending point is the glass transition temperature.

Here, as the above-mentioned triphenylmethane type phenol resin which is a polyfunctional phenol resin curing agent, for example, “HE910-09” (Air Water Co., Ltd., hydroxyl group equivalent: 92 to 104 g/eq, softening point: 75 to 85° C.) ) Can be used. The type and amount of the curing agent contained in the encapsulating composition of the present disclosure may be the same as or different from the type and amount of the curing agent used to obtain the cured product for measurement. May be
As the quinone adduct of the above organic phosphine compound, which is a phosphorus-based curing accelerator, for example, an adduct of tributylphosphine and benzoquinone can be used. When the encapsulating composition of the present disclosure contains a curing accelerator, the type and the addition amount of the curing accelerator contained in the encapsulating composition are the curing acceleration used for obtaining the cured product for measurement. The type and the addition amount of the agent may be the same or different.
Hereinafter, the "glass transition temperature when cured using a polyfunctional phenol resin curing agent and a phosphorus-based curing accelerator" may be referred to as "glass transition temperature after curing".

▽The above "epoxy group equivalent" is measured as follows. Specifically, "epoxy group equivalent" is measured by dissolving the epoxy resin to be measured in a solvent such as methyl ethyl ketone, adding acetic acid and tetraethylammonium bromide acetic acid solution, and then measuring with perchloric acid acetic acid standard solution. It is measured by potentiometric titration. An indicator may be used for this titration.

The following describes each component that constitutes the sealing composition. 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-
The epoxy resin is generally selected from the group consisting of phenol compounds (phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F, etc.) and naphthol compounds (α-naphthol, β-naphthol, dihydroxynaphthalene, etc.). At least one of the above and an aldehyde compound (formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, salicylaldehyde, etc.) are condensed or co-condensed under an acidic catalyst to obtain an epoxidized novolak resin (phenol novolac type epoxy). Resin, ortho-cresol novolac type epoxy resin, etc.); at least one dicarboxylic acid selected from the group consisting of bisphenol (bisphenol A, bisphenol AD, bisphenol F, bisphenol S, etc.) and biphenol (alkyl-substituted or unsubstituted biphenol, etc.) Glycidyl ether; epoxidized product of phenol/aralkyl resin; epoxidized product of addition product or polyaddition product of phenol compound and at least one selected from dicyclopentadiene and terpene compound; polybasic acid (phthalic acid, dimer Glycidyl ester type epoxy resin obtained by the reaction of epichlorohydrin with acid; glycidyl amine type epoxy resin obtained by the reaction of polyamine (diaminodiphenylmethane, isocyanuric acid, etc.) with epichlorohydrin; olefinic bond with peracid (peracetic acid, etc.) Examples thereof include linear aliphatic epoxy resins obtained by oxidation; 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 sealing composition of the present disclosure is the first epoxy resin having an epoxy group equivalent of 300 g/eq or more and a glass transition temperature after curing of 40° C. or less as described above. Contains at least. Further, the sealing composition of the present disclosure may contain an epoxy resin other than the first epoxy resin as necessary, and the melting point or softening point of 50° C. or higher as the resin other than the first epoxy resin. It is preferable to further contain a certain second epoxy resin.
The encapsulating composition of the present disclosure may contain an epoxy resin other than the first epoxy resin and the second epoxy resin (hereinafter, also referred to as “other epoxy resin”), if necessary. However, the total content of the first epoxy resin and the second epoxy resin, which is optionally contained, is preferably 90% by mass or more based on the total amount of all epoxy resins contained in the encapsulating composition. Is more preferably 95 mass% or more, further preferably 98 mass% or more.

(First epoxy resin)
The first epoxy resin is not particularly limited as long as it has an epoxy group equivalent of 300 g/eq or more and a glass transition temperature after curing of 40° C. or less.
The epoxy group equivalent in the first epoxy resin is 300 g/eq or more, preferably 350 g/eq or more, and more preferably 400 g/eq or more from the viewpoint of reducing the high temperature elastic modulus. Further, the epoxy group equivalent in the first epoxy resin is preferably 600 g/eq or less, more preferably 570 g/eq or less, and more preferably 540 g/eq or less from the viewpoint of ensuring the hardness during heating. Is more preferable. The epoxy group equivalent in the first epoxy resin is preferably 300 g/eq to 600 g/eq, and is 350 g/eq to 570 g/eq, from the viewpoint of simultaneously achieving a reduction in high temperature elastic modulus and a guarantee of hardness during heating. More preferably, it is more preferably 400 g/eq to 540 g/eq.

The glass transition temperature after curing in the first epoxy resin is 40° C. or lower, preferably 35° C. or lower, and more preferably 20° C. or lower from the viewpoint of reducing room temperature elastic modulus and high temperature elastic modulus. Further, the lower limit of the glass transition temperature after curing in the first epoxy resin is not particularly limited. The glass transition temperature after curing of the first epoxy resin is preferably −100° C. or higher, more preferably −85° C. or higher, and −75 from the viewpoint of ensuring the hardness during heating and reducing the thermal expansion coefficient. It is more preferable that the temperature is not lower than °C. The glass transition temperature after curing of the first epoxy resin is from −100° C. to 40° C. from the viewpoint of simultaneously achieving a reduction in room temperature elastic modulus and a high temperature elastic modulus as well as a guarantee of hardness during heating and a reduction in thermal expansion coefficient. The temperature is preferably −85° C. to 30° C., more preferably −75° C. to 20° C.

The first epoxy resin has at least two epoxy groups in the molecule. The number of epoxy groups contained in one molecule of the first epoxy resin is not particularly limited as long as the epoxy group equivalent in the first epoxy resin is in the above range, and may be 2-8, 2-6. Is preferable, 2 to 3 is more preferable, and 2 is particularly preferable.
The epoxy group is at least one selected from the group consisting of glycidyl group, glycidyloxy group, glycidyloxycarbonyl group, and epoxycycloalkyl group (epoxycyclopentyl group, epoxycyclohexyl group, epoxycyclooctyl group, etc.). As a part, it may be contained in the molecule of the first epoxy resin.

The first epoxy resin preferably has a divalent linking group represented by the following structural formula (1) in the molecule, in addition to two or more epoxy groups.
In the structural formula (1) below, * indicates a bonding part.

The first epoxy resin preferably has, in the molecule, at least one selected from the group consisting of a rubber elastic skeleton and a flexible skeleton, in addition to two or more epoxy groups. The first epoxy resin may have at least one kind selected from the group consisting of a rubber elastic skeleton and a flexible skeleton in the molecule, or may have two or more kinds.
Here, the rubber elastic skeleton is a partial structure that imparts rubber elasticity to the epoxy resin, and specific examples of the rubber elastic skeleton include alkyleneoxy groups and the like.
The flexible skeleton is a partial structure that imparts flexibility to the epoxy resin, and specific examples of the flexible skeleton include an alkyleneoxy group, a long-chain alkyl group, and a siloxane skeleton.

The first epoxy resin may have a skeleton containing an aromatic ring in addition to two or more epoxy groups in the molecule.
Examples of the skeleton containing an aromatic ring include a benzene ring skeleton, a naphthalene skeleton, a biphenyl skeleton, a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol AD skeleton, and a bisphenol S skeleton.

A commercially available product may be used as the first epoxy resin. The first epoxy resin may be used alone or in combination of two or more.

The content of the first epoxy resin with respect to the total amount of all epoxy resins contained in the encapsulating composition is preferably 10% by mass or more and 20% by mass or more from the viewpoint of reducing the room temperature elastic modulus and the high temperature elastic modulus. Is more preferable and 25% by mass or more is further preferable. The content of the first epoxy resin with respect to the total amount of all epoxy resins contained in the encapsulating composition is preferably 50% by mass or less and 45% by mass or less from the viewpoint of moldability of the encapsulating composition. Is more preferable, and 40% by mass or less is further preferable. The content of the first epoxy resin with respect to the total amount of all epoxy resins contained in the encapsulating composition is 10% by mass from the viewpoint of achieving both reduction in room temperature elastic modulus and high temperature elastic modulus and moldability of the encapsulating composition. It is preferably ˜50% by mass, more preferably 20% by mass to 45% by mass, and further preferably 25% by mass to 40% by mass.
The content of the first epoxy resin in the whole sealing composition is preferably 0.2% by mass to 3% by mass, more preferably 0.4% by mass to 1.5% by mass. More preferably, it is from 0.6% by mass to 1.1% by 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 has a melting point or a 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 (ring and ball method) according to JIS K 7234:1986.
The melting point or softening point of the second epoxy resin is preferably 50° C. or higher, more preferably 60° C. or higher, and 70° C. or higher from the viewpoint of moldability of the sealing composition. Is more preferable. In addition, the melting point or softening point of the second epoxy resin is preferably 150° C. or lower, more preferably 130° C. or lower, and further preferably 120° C. or lower, from the viewpoint of kneading properties during production. preferable. The melting point or softening point of the second epoxy resin is preferably 50° C. to 150° C., and more preferably 60° C. to 130° C. from the viewpoint of moldability of the sealing composition and kneading property during production. It is preferably 70° C. to 120° C., further preferably.

The epoxy group equivalent in the second epoxy resin is not particularly limited and is preferably less than 300 g/eq, and is 120 g/eq to 270 g/eq from the viewpoint of both moldability and reduction of high temperature elastic modulus. More preferably, it is more preferably 150 g/eq to 240 g/eq.
Further, the glass transition temperature after curing in the second epoxy resin is not particularly limited and is preferably higher than 40° C., and from the viewpoint of achieving both moldability and reduction of room temperature elastic modulus, it is from 80° C. to 200° C. More preferably, it is more preferably 120°C to 180°C.

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

The second epoxy resin preferably has a divalent linking group represented by the following general formula (2) in the molecule, in addition to two or more epoxy groups.
In the general formula (2) below, * represents a bond, and R ¹ to R ⁸ are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aromatic group having 4 to 18 carbon atoms. Indicates.

In the general formula (2), R ¹ to R ⁴ are each independently preferably 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 methyl group.
In the general formula (2), R ⁵ to R ⁸ are each independently preferably 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 with respect to the total amount of all epoxy resins contained in the encapsulating composition is 50% by mass to 90% by mass from the viewpoint of achieving both room temperature elastic modulus and high temperature elastic modulus reduction and moldability. It is preferably in the range of 55% by mass to 80% by mass, and more preferably in the range of 60% by mass to 75% by mass.
Further, the content ratio of the second epoxy resin to the entire sealing composition is preferably 1% by mass to 5% by mass, more preferably 1.5% by mass to 4% by mass, and 1.7. More preferably, it is from 3% by mass to 3% by mass.

The total epoxy resin content in the encapsulating composition is preferably 2.0% by mass to 6% by mass, more preferably 3.0% by mass to 5.5% by mass, and 3.0 It is more preferable that the content is from 5.0% 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 48% by mass to It is more preferably 55% by mass.

-Curing agent-
The sealing composition contains a curing agent. The type of curing agent is not particularly limited, and known curing agents 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. The curing agent is preferably a phenol curing agent, an amine curing agent, and an acid anhydride curing agent, and more preferably a phenol curing agent, from the viewpoint of obtaining a sealing composition having excellent reflow resistance while maintaining fluidity. The curing agent may be used alone or in combination of two or more.

Examples of phenol curing agents include phenol resins having two or more phenolic hydroxyl groups in one molecule, polyhydric phenol compounds, and the like. Specific examples of the phenol curing agent include resorcin, catechol, bisphenol A, bisphenol F, polyphenol compounds such as substituted or unsubstituted biphenol; phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F, At least one phenolic compound selected from the group consisting of phenol compounds such as phenylphenol and aminophenol and naphthol compounds such as α-naphthol, β-naphthol and dihydroxynaphthalene; and aldehyde compounds such as formaldehyde, acetaldehyde and propionaldehyde, An aralkyl-type phenol resin (phenol aralkyl resin, which is synthesized from the above-mentioned phenolic compound, dimethoxyparaxylene, bis(methoxymethyl)biphenyl, and the like; Naphthol aralkyl resin, etc.); para-xylylene-modified phenol resin; meta-xylylene-modified phenol resin; melamine-modified phenol resin; terpene-modified phenol resin; dicyclopentadiene-type phenol resin synthesized by copolymerization of the above phenolic compound and dicyclopentadiene Cyclopentadiene-type naphthol resin; cyclopentadiene-modified phenol resin; polycyclic aromatic ring-modified phenol resin; biphenyl-type phenol resin; the above phenolic compound and an aromatic aldehyde compound such as benzaldehyde or salicylaldehyde are condensed under an acidic catalyst or Examples thereof include a triphenylmethane type phenol resin obtained by cocondensation; a phenol resin obtained by copolymerizing two or more of these. These phenol resins and polyhydric phenol compounds may be used alone or in combination of two or more.

Among these, the phenol curing agent is preferably a polyfunctional phenol resin, of which a novolac type phenol resin, an aralkyl type phenol resin, and a triphenylmethane type phenol resin are preferable, and a triphenylmethane type phenol resin is more preferable.

Examples of the triphenylmethane type phenol resin include a phenol resin represented by the following general formula (3).

In the general formula (3), R ¹¹ to R ¹⁵ each independently represent a monovalent organic group having 1 to 18 carbon atoms, and b 1 to b 2 each independently represent an integer of 0 to 4, b3 represents an integer of 0 to 3, b4 to b5 each independently represents an integer of 0 to 4, and n represents 0 to 10.

The monovalent organic group having 1 to 18 carbon atoms represented by R ¹¹ to R ¹⁵ in the general formula (3) includes a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted Examples thereof include an aryl group and a substituted or unsubstituted aralkyl group.
B1 to b5 in the general formula (3) are preferably integers of 0 to 1, more preferably 0, and n in the general formula (3) is preferably 1 to 7. More preferably, it is -5.

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

When the curing agent is solid, its softening point or melting point is not particularly limited. The softening point or melting point of the curing agent is preferably 40° C. to 180° C. from the viewpoint of moldability and reflow resistance, and the softening point or melting point from the viewpoint of handleability during production of the sealing composition. Is more preferably 50° C. to 130° C., 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.

The mixing ratio of the epoxy resin and the curing agent is such that the equivalent of the functional group of the curing agent (for example, a phenolic hydroxyl group in the case of a phenol resin) is equal to one equivalent of the epoxy group of the epoxy resin from the viewpoint of suppressing each unreacted component. On the other hand, it is preferable to add the curing agent so as to be 0.5 equivalent to 1.5 equivalents, and particularly preferable to add the curing agent so as to be 0.7 equivalent to 1.2 equivalents. ..

-Inorganic filler-
The inorganic filler may be used alone or in combination of two or more.
Examples of the case where two or more kinds of inorganic fillers are used in combination include a case where two or more kinds of inorganic fillers having different components, average particle diameters, shapes, etc. are used.
The shape of the inorganic filler is not particularly limited, and examples thereof include powder, sphere, and fiber. The shape of the inorganic filler is preferably spherical from the viewpoints of fluidity during molding of the encapsulating composition and mold wear resistance.

The inorganic filler preferably contains alumina from the viewpoint of high thermal conductivity. All the inorganic fillers may be alumina, or alumina and other inorganic fillers may be used in combination.
Other inorganic fillers that can be used in combination with alumina include spherical silica, silica such as crystalline silica, zircon, magnesium oxide, calcium silicate, calcium carbonate, potassium titanate, silicon carbide, silicon nitride, boron nitride, beryllia and zirconia. Are listed. Furthermore, examples of the inorganic filler having a flame retardant effect include aluminum hydroxide and zinc borate.

When alumina and other inorganic fillers are used together as the inorganic filler, silica is preferably used as the other inorganic filler from the viewpoint of fluidity.
When alumina and silica are used together 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, and 85% by mass or more. Is more preferable, and 95% by mass or more is particularly preferable. Further, the content rate of alumina in the inorganic filler may be 99.6% by mass or less.

From the viewpoint of hygroscopicity, reduction of linear expansion coefficient, strength improvement, and solder heat resistance, the content of the inorganic filler is preferably 60% by volume or more, and 70% by volume with respect to the entire sealing composition. More preferably, it is more preferably 75% by volume or more.
From the viewpoint of high thermal conductivity, the content of the inorganic filler is preferably 78% by volume or more, more preferably 80% by volume or more, based on the whole sealing composition. From the viewpoint of moldability and fluidity of the sealing composition, the content of the inorganic filler is preferably 95% by volume or less, and more preferably 90% by volume or less with respect to the entire sealing composition. It is preferably 85% by volume or less, and more preferably 85% by volume or less. The content of the inorganic filler is preferably 78% by volume to 90% by volume, more preferably 78% by volume to 85% by volume, from the viewpoint of achieving both high thermal conductivity and moldability and fluidity of the sealing composition. 80% by volume to 85% by volume is more preferable.

The average particle size of the inorganic filler is preferably 4 μm to 100 μm, more preferably 7 μm to 70 μm, and further preferably 7 μm to 40 μm. In the present disclosure, the average particle diameter of the inorganic filler is the average particle diameter of alumina when alumina is used alone as the inorganic filler, and alumina and other inorganic fillers are used as the inorganic filler in combination. In this case, the average particle size of the whole inorganic filler is referred to.
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) together with 1% to 8% by mass of the surfactant within the range of 1% to 5% by mass, and the ultrasonic cleaning machine of 110 W is used for 30 seconds to 5%. Vibrate for minutes to disperse the inorganic filler. About 3 mL of the dispersion liquid is injected into the measuring cell and measurement is performed at 25°C. A laser diffraction type particle size distribution meter (LA920, Horiba, Ltd.) is used as a measuring device, and the particle size distribution based on volume is measured. The average particle diameter is obtained as the particle diameter (D50%) when the accumulation from the small diameter side is 50% in the volume-based particle size distribution. The refractive index of alumina is used as the refractive index. When the inorganic filler is a mixture of alumina and another inorganic filler, the refractive index of alumina is used as the refractive index.

The specific surface area of the inorganic filler, from the viewpoint of fluidity and moldability, is preferably from 0.7m ^² /g~4.0m ² / g, with 0.9m ^² /g~3.0m ² / g more preferably in, still more preferably 1.0m ^² /g~2.5m 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 the inorganic filler is the specific surface area of alumina when, for example, alumina is used alone as the inorganic filler, and alumina and other inorganic fillers are used in combination as the inorganic filler. If so, it refers to the specific surface area of the mixture of inorganic fillers.
The specific surface area (BET specific surface area) of the inorganic filler can be measured from the nitrogen adsorption capacity according to JIS Z 8830:2013. As an evaluation device, QUANTACHROME company: AUTOSORB-1 (trade name) can be used. When the BET specific surface area is measured, it is considered that the water adsorbed on the sample surface and structure influences the gas adsorption ability. Therefore, it is preferable to first perform a pretreatment for removing water by heating. ..
In the pretreatment, the measurement cell charged with 0.05 g of the measurement sample was depressurized to 10 Pa or less by a vacuum pump, heated at 110° C., held for 3 hours or more, and then kept at room temperature (vacuum) while maintaining the depressurized state. Cool naturally to 25°C). After performing this pretreatment, the evaluation temperature is set to 77K, and the evaluation pressure range is measured as relative pressure (equilibrium pressure to saturated vapor pressure) of less than 1.

-Other ingredients-
(Curing accelerator)
The sealing composition may further contain a curing accelerator. The type of curing accelerator is not particularly limited, and known curing accelerators can be used.
Specific examples of the curing accelerator include 1,8-diaza-bicyclo[5.4.0]undecene-7, 1,5-diaza-bicyclo[4.3.0]nonene and 5,6-dibutyl. Cycloamidine compounds such as amino-1,8-diaza-bicyclo[5.4.0]undecene-7; cycloamidine compounds with maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, phenyl-1,4-benzoquinone Compounds having an intramolecular polarization formed by adding a compound having a π bond such as a quinone compound such as diazophenylmethane or phenol resin; benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris(dimethylaminomethyl)phenol, etc. Tertiary amine compounds; derivatives of tertiary amine compounds; imidazole compounds such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole; derivatives of imidazole compounds; tributylphosphine, methyldiphenylphosphine, triphenyl Organic phosphine compounds such as phosphine, tris(4-methylphenyl)phosphine, diphenylphosphine and phenylphosphine; Maleic anhydride, the above quinone compound, diazophenylmethane, compounds having a π bond such as phenol resin are added to the organic phosphine compound. A phosphorus compound having an intramolecular polarization: tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, 2-ethyl-4-methylimidazole tetraphenylborate, tetraphenylboron salt such as N-methylmorpholine tetraphenylborate; Derivatives of tetraphenylboron salts; adducts of phosphine compounds such as triphenylphosphonium-triphenylborane, N-methylmorpholine tetraphenylphosphonium-tetraphenylborate and tetraphenylboron salts; and the like. The curing accelerator may be used alone or in combination of two or more.

Of these, the curing accelerator is preferably a phosphorus-based curing accelerator, and among them, an organic phosphine compound, an adduct of an organic phosphine compound, and an adduct of a phosphine compound and a tetraphenylboron salt are more preferable, and an organic phosphine compound and An adduct of an organic phosphine compound is more preferable, and a compound obtained by adding a quinone compound to an organic phosphine compound is particularly preferable.

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

(Ion trap agent)
The sealing composition may further contain an ion trap agent.
The ion trap agent that can be used in the present disclosure is not particularly limited as long as it is an ion trap agent that is generally used in the encapsulating material used for manufacturing semiconductor devices. Examples of the ion trapping agent include compounds represented by the following general formula (4) or the following general formula (5).

Mg _1-a Al _a (OH) ₂ (CO ₃ ) _a/2 ·uH ₂ O (4)
(In the general formula (4), a is 0<a≦0.5, and u is a positive number.)
BiO _b (OH) _c (NO ₃ ) _d (5)
(In the general formula (5), b is 0.9≦b≦1.1, c is 0.6≦c≦0.8, and d is 0.2≦d≦0.4.)

Ion trap agents are available as commercial products. As the compound represented by the general formula (4), for example, “DHT-4A” (Kyowa Chemical Industry Co., Ltd., trade name) is commercially available. As the compound represented by the general formula (5), for example, “IXE500” (Toagosei Co., Ltd., trade name) is commercially available.

Examples of ion trapping agents other than those mentioned above include hydrous oxides of elements selected from the group consisting of magnesium, aluminum, titanium, zirconium, antimony and the like.
The ion trap agents may be used alone or in combination of two or more.

When the sealing composition contains an ion trap agent, the content of the ion trap agent is preferably 1 part by mass or more based on 100 parts by mass of the epoxy resin from the viewpoint of realizing sufficient moisture resistance reliability. .. From the viewpoint of sufficiently exerting the effect of other components, the content of the ion trap agent is preferably 15 parts by mass or less with respect to 100 parts by mass of the epoxy resin.

The average particle size of the ion trap 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 trap agent can be measured in the same manner as in the case of the inorganic filler.

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

Examples of 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-aminopropyltrimethoxysilane, γ-(β-aminoethyl)aminopropyldimethoxymethylsilane, N-(trimethoxysilylpropyl)ethylenediamine, N-( Dimethoxymethylsilylisopropyl)ethylenediamine, methyltrimethoxysilane, methyltriethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, Examples include γ-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane and the like.

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). 2-diallyloxymethyl-1-butyl)bis(ditridecyl phosphite)titanate, bis(dioctylpyrophosphate)oxyacetate titanate, bis(dioctylpyrophosphate)ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate , Isopropyl tridodecyl benzene sulfonyl titanate, isopropyl isostearoyl diacrylic titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, tetraisopropyl bis(dioctyl phosphite) titanate and the like.

-Specific silane compound-
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 “specific silane compound”). Good.
The chain hydrocarbon group may be branched or may have a substituent. In addition, in this indication, carbon number of a chain hydrocarbon group means carbon number which does not contain carbon of a branch or a 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 a silicon atom in the specific silane compound may be 1 to 4, preferably 1 to 3, more preferably 1 or 2, and 1 Is more preferable.

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

The carbon number of the chain hydrocarbon group of the specific silane compound is 6 or more, preferably 7 or more, and more preferably 8 or more from the viewpoint of suppressing the viscosity. The upper limit of the number of carbon atoms of the chain hydrocarbon group of the specific silane compound is not particularly limited, and is preferably 12 or less, and more preferably 11 or less from the viewpoint of dispersibility in resin, physical property balance of the cured product, and the like. More preferably, it is 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 may be present at the side chain of the chain hydrocarbon group.

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

When the chain hydrocarbon group has an epoxy group, the epoxy group may be bonded directly 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. Among them, the chain hydrocarbon group preferably 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 the chain hydrocarbon group may be bonded. It is preferred that it is directly bonded to. The alkoxy group is not particularly limited and may be a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group and the like. Among them, the chain hydrocarbon group preferably has a methoxy group from the viewpoint of easy availability.

The equivalent (molecular weight/number of functional groups) of at least one functional group selected from the group consisting of (meth)acryloyl group, epoxy group, and alkoxy group in the specific silane compound is not particularly limited. From the viewpoint of lowering 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 further preferably 230 g/eq to 390 g/eq. More preferable.

Specific silane compounds include hexyltrimethoxysilane, heptyltrimethoxysilane, octyltrimethoxysilane, hexyltriethoxysilane, heptyltriethoxysilane, octyltriethoxysilane, 6-glycidoxyhexyltrimethoxysilane, 7-glycid Xyheptyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, 6-(meth)acryloxyhexyltrimethoxysilane, 7-(meth)acryloxyheptyltrimethoxysilane, 8-(meth)acryloxyoctyltrimethoxysilane Examples thereof include silane and decyltrimethoxysilane. Among them, 8-glycidoxyoctyltrimethoxysilane and 8-methacryloxyoctyltrimethoxysilane are preferable as the specific silane compound from the viewpoint of lowering the viscosity of the sealing composition. 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 one may be used. Specific commercially available silane compounds include Shin-Etsu Chemical Co., Ltd. KBM-3063 (hexyltrimethoxysilane), KBE-3063 (hexyltriethoxysilane), KBE-3083 (octyltriethoxysilane), KBM-4803 ( 8-glycidoxyoctyltrimethoxysilane), KBM-5803 (8-methacryloxyoctyltrimethoxysilane), KBM-3103C (decyltrimethoxysilane) and the like can be mentioned.

When the sealing composition contains a coupling agent, the content of the coupling agent is preferably 3% by mass or less, more preferably 2% by mass or less, and more preferably 1% by mass, based on the entire sealing composition. % Or less is more preferable, and from the viewpoint of exerting the effect, it is preferably 0.1% by mass or more, more preferably 0.15% by mass or more, and further preferably 0.2% by mass or more.
The content of the coupling agent may be 0.01 parts by mass or more, and may be 0.02 parts by mass or more, based on 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 with respect to 100 parts by mass of the inorganic filler. The content of the coupling agent is preferably 0.05 parts by mass to 2.0 parts by mass, and 0.1 parts by mass with respect to 100 parts by mass of the inorganic filler, from the viewpoint of achieving both fluidity and moldability of the package. It is more preferably to 1.5 parts by mass, still more preferably 0.2 parts to 1.0 parts by mass.

(Release agent)
The sealing composition may further contain a release agent. The type of release agent is not particularly limited, and known release agents can be used. Specifically, examples of the release agent include higher fatty acids, carnauba wax, montan wax, polyethylene wax and the like. The release agent may be used alone or in combination of two or more.
When the sealing composition contains a release agent, the content of the release agent is preferably 10% by mass or less based on the total amount of the epoxy resin and the curing agent, and from the viewpoint of exerting the effect. Is preferably 0.5% by mass or more.

(Colorants and modifiers)
The sealing composition may contain a colorant (carbon black or the like). Further, the sealing composition may contain a modifier (silicone, silicone rubber, etc.). Each of the colorant and the modifier may be used alone or in combination of two or more.

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% by mass or less.
When the sealing composition contains conductive particles, the content of the conductive particles is preferably 3% by 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 and the like. Further, various additives well known in the art may be added to the composition, if necessary.

<Method for producing sealing composition>
The method for producing the sealing composition is not particularly limited, and a known method can be used. For example, a sealing composition can be prepared by thoroughly mixing a mixture of raw materials in a predetermined amount with a mixer or the like, kneading the mixture with a heat roll, an extruder, or the like, and then cooling, pulverizing, or the like. The state of the sealing composition is not particularly limited and may be powdery, solid, liquid or the like.

<Semiconductor device>
A semiconductor device of the present disclosure includes a semiconductor element and a cured product of the sealing composition of the present disclosure obtained by sealing the semiconductor element.

The method of sealing the semiconductor element with the sealing composition is not particularly limited, and a known method can be applied. A transfer molding method or the like is generally used, but a compression molding method, an injection molding method, a compression molding method or the like may be used.

The semiconductor device of the present disclosure is suitable as an IC (Integrated Circuit, integrated circuit), an LSI (Large-Scale Integration, large-scale integrated circuit), or the like.

An embodiment of the present invention will be described below with reference to the following examples, but the present invention is not limited to these. The numerical values in the table mean "parts by mass" unless otherwise specified.

<Examples 1 to 5 and Comparative Example 1>
The components shown below were premixed (dry blended) at the blending ratio (parts by mass) shown in Table 1, kneaded with a biaxial kneader, and cooled and pulverized to produce a powdery sealing composition.
The details of the components shown in Table 1 are as follows.

(A) Epoxy resin Epoxy resin A1-1: First epoxy resin, Mitsubishi Chemical Corporation, epoxy group equivalent “440 g/eq”, glass transition temperature after curing “−57° C.”, two epoxy groups in the molecule, Epoxy Resin Having Rubber Elastic Skeleton and Divalent Linking Group Represented by Structural Formula (1) Epoxy Resin A1-2: First Epoxy Resin, Mitsubishi Chemical Co., Epoxy Group Equivalent “489 g/eq”, Epoxy resin having a glass transition temperature after curing “31° C.”, two epoxy groups in the molecule, a flexible skeleton, a skeleton containing an aromatic ring, and a divalent linking group represented by the structural formula (1). Epoxy resin A1 -3: First epoxy resin, Mitsubishi Chemical Corporation, epoxy group equivalent "501 g/eq", glass transition temperature after curing "19°C", epoxy resin having two epoxy groups in the molecule Epoxy resin A2: second Epoxy resin, Mitsubishi Chemical Corporation, product name "YX4000H", epoxy group equivalent "192 g/eq", glass transition temperature after curing "150°C", softening point "107°C", biphenyl type epoxy resin

Here, the value of the glass transition temperature after curing in the epoxy resin is the epoxy resin to be measured, "HE910-09" (Air Water Co., Ltd.) which is a polyfunctional phenol resin curing agent, and phosphorus-based curing acceleration. It is the value of the glass transition temperature in the cured product for measurement, which was obtained by heating the mixture obtained by mixing the agent "addition product of tributylphosphine and benzoquinone" at 175°C for 6 hours.
In the preparation of the cured product for measurement, the number of epoxy groups (that is, the total number) of the epoxy resin that is the measurement target of the polyfunctional phenol resin curing agent and the number of the hydroxyl groups (that is, the total number) of the phenol resin are approximately the same. The phosphorus-based curing accelerator is added so that the content of the phosphorus-based curing accelerator is 3 to 6 parts by mass with respect to 100 parts by mass of the epoxy resin and the polyfunctional phenol resin curing agent in total. did.
Further, the glass transition temperature is measured by cutting the obtained cured product for measurement, weighing 10 mg, and using a differential scanning calorimeter (TA Instruments Japan Co., product name "DSC Q100"). The temperature was raised at a rate of 10° C./min, and the glass transition temperature was defined as the intersection of tangents before and after the inflection point of the obtained chart.

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

(C) Curing accelerator Curing accelerator C1: Phosphorus curing accelerator (addition product 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 Company, Product Name “HW-E”
(F) Colorant Pigment F1: Carbon black, Mitsubishi Chemical Corporation, trade name "MA600"
(G) Additive Additive G1: Triphenylphosphine oxide (H) Modifier Modifier H1: Silicone, Toray Dow Corning Co., Ltd., product name "BY16-876"

(I) Inorganic filler filler I1: silica particles, spherical, specific surface area "190 m ² /g to 230 m ² /g"
Filler I2: Alumina particles, spherical, average particle size “0.7 μm”
Filler I3: Alumina particles, spherical, average particle size “10 μm”

-Evaluation-
The characteristics of the sealing compositions produced in the examples and comparative examples were evaluated by the following characteristic tests. The evaluation results are shown in Table 1 below.

(Hardness when heated)
Using the sealing composition obtained above, a transfer molding machine was used to perform molding at a mold temperature of 175° C., a molding pressure of 6.9 MPa, and a curing time of 90 seconds, and a disk-shaped test with a diameter of 50 mm and a thickness of 3 mm was performed. Pieces were made. Immediately after molding, the hot hardness of the cured product was measured using a Shore D hardness meter (Kobunshi Keiki Co., Ltd., Asker, type D durometer).

(Room temperature elastic modulus and high temperature elastic modulus)
Using the sealing composition obtained above, a test piece having a shape of 127 mm×12.7 mm×4 mm was formed 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. Was produced. Then, post-curing was performed at 175° C. for 6 hours. Using Tensilon (A&D Co.) as an evaluation device, a three-point support type bending test based on JIS-K-7171 (2016) was carried out at 25° C. and 260° C., and the bending elastic modulus of the test piece was obtained.
The flexural modulus E is defined by the following formula, and the flexural modulus obtained by measurement at 25° C. is referred to as “room temperature modulus” and the flexural modulus obtained at 260° C. is referred to as “high temperature modulus”. To do.
In the following formula, E is a bending elastic modulus (MPa), P is a load cell value (N), y is a displacement amount (mm), l is a span=64 mm, w is a test piece width=12.7 mm, and h is a test piece. Thickness=4 mm.

(Thermal conductivity)
Using the above-obtained sealing composition, a transfer molding machine was used to prepare a test piece for thermal conductivity evaluation 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 of the molded test piece in the thickness direction was measured. The thermal diffusivity was measured by the laser flash method (apparatus: LFA467 nanoflash, NETZSCH). The pulsed light irradiation was performed under the conditions of a pulse width of 0.31 (ms) and an applied voltage of 247V. The measurement was performed at an ambient temperature of 25°C ± 1°C. The density of the test piece was measured using an electronic hydrometer (AUX220, Shimadzu Corporation). As the specific heat, the theoretical specific heat of the sealing composition calculated from the literature value of the specific heat of each material and the compounding ratio was used.
The thermal diffusivity was then obtained by multiplying the thermal diffusivity by the specific heat and density using equation (6).
λ=α×Cp×ρ... Formula (6)
(In Formula (6), 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. (Indicates kg/m ³ respectively.)
The results are shown in Table 1.

In Table 1, "average particle size of filler" means the volume-based average particle size of the whole inorganic filler used, and "filler content" is the content of the whole inorganic filler used with respect to the entire sealing composition. Means
As is clear from the evaluation results of Table 1, the sealing compositions of Examples 1 to 5 containing the first epoxy resin were compared with the sealing composition of Comparative Example 1 containing no first epoxy resin. As a result, a cured product having a low room temperature elastic modulus and a high temperature elastic modulus is obtained. Further, the thermal conductivity of the cured products of the sealing compositions of Examples 1 to 5 is equal to or higher than the thermal conductivity of the cured products of the sealing composition of Comparative Example 1. Further, the sealing compositions of Examples 1 to 5 have lower room temperature elastic modulus and high temperature elastic modulus as compared with the sealing composition of Comparative Example 1, while maintaining the hot hardness.

The disclosure of Japanese Patent Application No. 2018-239253 filed on Dec. 21, 2018 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned herein are to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference, Incorporated herein.

Claims

A first epoxy resin having an epoxy group equivalent of 300 g/eq or more and having a glass transition temperature of 40° C. or less when cured using a polyfunctional phenol resin curing agent and a phosphorus-based curing accelerator;
A curing agent,
An inorganic filler,
A sealing composition containing:
The encapsulating composition according to claim 1, wherein the content of the inorganic filler is 78% by volume or more based on the entire encapsulating composition.
The encapsulating composition according to claim 1 or 2, further comprising a second epoxy resin having a melting point or a softening point of 50°C or higher.
The encapsulating composition according to any one of claims 1 to 3, wherein the content of the first epoxy resin is 20% by mass or more based on the total amount of the epoxy resins contained in the encapsulating composition. Stuff.
The encapsulating composition according to any one of claims 1 to 4, wherein the content of the first epoxy resin is 50% by mass or less based on the total amount of the epoxy resins contained in the encapsulating composition. Stuff.
The encapsulating composition according to any one of claims 1 to 5, wherein the first epoxy resin has two epoxy groups in the molecule.
The sealing composition according to any one of claims 1 to 6, wherein the first epoxy resin has a divalent linking group represented by the following structural formula (1) in the molecule.

(In the structural formula (1), * represents a bonding portion.)
A semiconductor device comprising a semiconductor element and a cured product of the encapsulating composition according to any one of claims 1 to 7 obtained by encapsulating the semiconductor element.