JP2024091762A - Resin composition for transfer molding and semiconductor device - Google Patents

Abstract

The present invention provides an encapsulating resin composition capable of forming a cured product having excellent adhesion to silicon nitride while maintaining a low dielectric tangent at 20 GHz, and a semiconductor device including elements encapsulated therewith.
The encapsulating resin composition contains an epoxy resin and a curing agent including an active ester compound and a nitrogen-containing phenol compound.
[Selection diagram] None

Description

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

In recent years, computers, information and communication devices, etc., have become increasingly sophisticated and functional, and in order to process large amounts of data at high speed, the signals they handle tend to be of higher frequency. When handling signals in the high frequency range (e.g., 20 GHz or higher), it is desirable for the transmission loss to be small. From the viewpoint of keeping this transmission loss small, a material with a low dielectric loss tangent is also desirable for the cured product of an encapsulating resin composition that encapsulates elements of a semiconductor device.
Here, Patent Document 1 discloses a thermosetting resin composition containing an active ester resin as a curing agent for epoxy resin, and is said to be capable of keeping the dielectric tangent of the cured product low.

JP 2012-246367 A

In recent years, silicon nitride has tended to be used as a next-generation substrate material in semiconductor materials, and therefore high adhesion to silicon nitride is desired in cured products of encapsulating resin compositions for encapsulating elements of semiconductor devices.
In view of the above circumstances, an object of the present disclosure is to provide an encapsulating resin composition capable of forming a cured product having excellent adhesion to silicon nitride while maintaining a low dielectric tangent at 20 GHz, and a semiconductor device including an element encapsulated therewith.

The means for solving the above problems include the following embodiments:

[1] an epoxy resin;
a curing agent including an active ester compound and a nitrogen-containing phenolic compound;
An encapsulating resin composition comprising:

[2] The encapsulating resin composition according to [1], wherein the nitrogen-containing phenol compound has a hydroxyl group equivalent of 100 g/eq or more.

[3] The encapsulating resin composition according to [1] or [2], wherein the nitrogen-containing phenol compound includes a nitrogen-containing heterocyclic compound.

[4] The encapsulating resin composition according to [3], wherein the nitrogen-containing heterocyclic compound includes a heterocyclic compound having two or more nitrogen atoms as atoms constituting the heterocyclic skeleton.

[5] The encapsulating resin composition according to any one of [1] to [4], wherein the content of the nitrogen-containing phenol compound is 15 mass% or less relative to the total amount of the curing agent.

[6] The encapsulating resin composition according to any one of [1] to [5] above, further comprising an inorganic filler.

[7] The encapsulating resin composition according to [6], wherein the content of the inorganic filler in the encapsulating resin composition is 65% by volume or more.

[8] A semiconductor device comprising a semiconductor element and a cured product of the encapsulating resin composition described in any one of [1] to [7] above, which encapsulates the semiconductor element.

The present disclosure provides an encapsulating resin composition capable of forming a cured product with excellent adhesion to silicon nitride while maintaining a low dielectric tangent at 20 GHz, and a semiconductor device having an element encapsulated therewith.

In the present disclosure, the term "step" includes not only a step that is independent of other steps, but also a step that cannot be clearly distinguished from other steps as long as the purpose of the step is achieved.
In the present disclosure, the numerical range indicated using "to" includes 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.

-Sealing resin composition-
The encapsulating resin composition of the present disclosure contains an epoxy resin and a curing agent including an active ester compound and a nitrogen-containing phenol compound. The encapsulating resin composition may contain other additives.

The encapsulating resin composition of the present disclosure can form a cured product that has excellent adhesion to silicon nitride while maintaining a low dielectric tangent at 20 GHz. The reason for this is not entirely clear, but is thought to be as follows.

The encapsulating resin composition of the present disclosure contains an active ester compound as a curing agent. Phenol curing agents, which are generally used as curing agents for epoxy resins, tend to generate secondary hydroxyl groups in a reaction with the epoxy resin. In contrast, when an active ester compound is used as a curing agent, an ester group is generated instead of a secondary hydroxyl group in a curing reaction with the epoxy resin. The ester group has a lower polarity than a secondary hydroxyl group and is less likely to polarize. Therefore, it is considered that the dielectric tangent of the cured product can be kept low when an active ester compound is used, compared to when a curing agent such as a phenolic resin that generates secondary hydroxyl groups is used.
On the other hand, it was revealed that when an active ester compound is used as a curing agent, the adhesiveness of the resulting cured product to silicon nitride is reduced. Thus, it was found that there is a trade-off between using an active ester compound as a curing agent, which can keep the dielectric tangent of the resulting cured product low, but which also reduces the adhesiveness to silicon nitride.

In contrast, the encapsulating resin composition of the present disclosure contains a nitrogen-containing phenolic compound as a curing agent in addition to the active ester compound. It is believed that the nitrogen atom site in the nitrogen-containing phenolic compound improves adhesion to the silicon nitride substrate. In addition, although the degree of reactivity of the phenol site in the nitrogen-containing phenolic compound with the epoxy resin is not clear, it is believed that the curing reaction between the active ester compound and the epoxy resin is not inhibited because the dielectric tangent of the cured product is maintained low.

[Epoxy resin]
The encapsulating resin composition contains an epoxy resin.
The type of epoxy resin contained in the encapsulating resin composition of the present disclosure is not particularly limited.
Specific examples of epoxy resins include novolac-type epoxy resins (phenol novolac-type epoxy resins, orthocresol novolac-type epoxy resins, etc.) obtained by epoxidizing a novolac resin 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, etc., and naphthol compounds such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc., with an aliphatic aldehyde compound such as formaldehyde, acetaldehyde, propionaldehyde, etc., under an acidic catalyst; and triphenylmethane-type epoxy resins obtained by epoxidizing a triphenylmethane-type phenolic resin obtained by condensing or co-condensing the above-mentioned phenolic compound with an aromatic aldehyde compound such as benzaldehyde, salicylaldehyde, etc., under an acidic catalyst. copolymer type epoxy resins obtained by epoxidizing novolak resins obtained by co-condensing the above-mentioned phenol compounds and naphthol compounds with aldehyde compounds under an acidic catalyst; diphenylmethane type epoxy resins which are diglycidyl ethers of bisphenol A, bisphenol F, etc.; biphenyl type epoxy resins which are diglycidyl ethers of aralkyl-substituted, alkyl-substituted or unsubstituted biphenols; stilbene type epoxy resins which are diglycidyl ethers of stilbene-based phenol compounds; sulfur atom-containing epoxy resins which are diglycidyl ethers of bisphenol S, etc.; epoxy resins which are glycidyl ethers of alcohols such as butanediol, polyethylene glycol, polypropylene glycol, etc.; glycidyl ester type epoxy resins which are glycidyl esters of polyvalent carboxylic acid compounds such as phthalic acid, isophthalic acid, tetrahydrophthalic acid, etc.; aniline, diamine glycidylamine-type epoxy resins in which active hydrogen bonded to nitrogen atoms of dicyclopentadiene, diphenylmethane, isocyanuric acid, etc. is replaced with a glycidyl group; dicyclopentadiene-type epoxy resins in which a co-condensation resin of dicyclopentadiene and a phenol compound is epoxidized; alicyclic epoxy resins such as vinylcyclohexene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane in which an olefin bond in a molecule is epoxidized; paraxylylene-modified epoxy resins which are glycidyl ethers of paraxylylene-modified phenolic resins; metaxylylene-modified epoxy resins which are glycidyl ethers of metaxylylene-modified phenolic resins; terpene-modified epoxy resins which are glycidyl ethers of terpene-modified phenolic resins. Epoxy resins; dicyclopentadiene-modified epoxy resins which are glycidyl ethers of dicyclopentadiene-modified phenolic resins; cyclopentadiene-modified epoxy resins which are glycidyl ethers of cyclopentadiene-modified phenolic resins; polycyclic aromatic ring-modified epoxy resins which are glycidyl ethers of polycyclic aromatic ring-modified phenolic resins; naphthalene-type epoxy resins which are glycidyl ethers of naphthalene ring-containing phenolic resins; halogenated phenol novolac-type epoxy resins; hydroquinone-type epoxy resins; trimethylolpropane-type epoxy resins; linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid; aralkyl-type epoxy resins obtained by epoxidizing aralkyl-type phenolic resins such as phenol aralkyl resins, naphthol aralkyl resins, and biphenyl aralkyl resins; aralkyl-type phenolic resins and biphenols. Furthermore, epoxy compounds of acrylic resins and the like can also be mentioned as epoxy resins.
Among the above, as the epoxy resin, aralkyl type epoxy resin, biphenyl type epoxy resin, etc. are preferred.
The epoxy resins may be used alone or in combination of two or more.

The epoxy equivalent (molecular weight/number of epoxy groups) of the epoxy resin is not particularly limited. From the viewpoint of the balance of various properties such as moldability, reflow resistance, and electrical reliability, it is preferably 100 g/eq to 1000 g/eq, and more preferably 150 g/eq to 500 g/eq.

The epoxy equivalent of the epoxy resin is the value measured using a method conforming to JIS K 7236:2009.

When the epoxy resin is a solid, its softening point or melting point is not particularly limited. From the viewpoints of moldability and reflow resistance, it is preferably 40°C to 180°C, and from the viewpoint of handleability when preparing the encapsulating resin composition, it is more preferably 50°C to 130°C.

The melting point or softening point of the epoxy resin is a value measured by differential scanning calorimetry (DSC) or a method conforming to JIS K 7234:1986 (ring and ball method).

From the viewpoints of strength, fluidity, heat resistance, moldability, etc., the content of the epoxy resin in the encapsulating resin composition is preferably 0.5% by mass to 50% by mass, and more preferably 2% by mass to 30% by mass.

[Curing agent]
The encapsulating resin composition contains a curing agent.
The curing agent includes an active ester compound and a nitrogen-containing phenol compound. The encapsulating resin composition may include a curing agent other than the active ester compound and the nitrogen-containing phenol compound.

(Active ester compound)
In the present disclosure, an active ester compound refers to a compound that has one or more ester groups in one molecule that react with an epoxy group and has a curing action for an epoxy resin.

As described above, the encapsulating resin composition of the present disclosure can maintain the dielectric tangent of the cured product low by using an active ester compound as a curing agent.
In addition, polar groups in the cured product increase the water absorption of the cured product, and the use of an active ester compound as a curing agent tends to reduce the polar group concentration of the cured product and thus reduce the water absorption of the cured product. It is believed that by reducing the water absorption of the cured product, that is, by reducing the content of H ₂ O, which is a polar molecule, the dielectric tangent of the cured product can be further reduced. The water absorption rate of the cured product is preferably 0% to 0.35%, more preferably 0% to 0.30%, and even more preferably 0% to 0.25%. Here, the water absorption rate of the cured product is the mass increase rate determined by a pressure cooker test (121°C, 2.1 atm, 24 hours).

There are no particular limitations on the type of active ester compound, so long as it is a compound that has one or more ester groups in the molecule that react with an epoxy group.

Examples of active ester compounds include phenol ester compounds, thiophenol ester compounds, N-hydroxyamine ester compounds, and esters of heterocyclic hydroxy compounds.

Examples of active ester compounds include ester compounds obtained from at least one of an aliphatic carboxylic acid and an aromatic carboxylic acid and at least one of an aliphatic hydroxy compound and an aromatic hydroxy compound. Ester compounds having an aliphatic compound as a polycondensation component tend to have excellent compatibility with epoxy resins due to the presence of an aliphatic chain. Ester compounds having an aromatic compound as a polycondensation component tend to have excellent heat resistance due to the presence of an aromatic ring.

Specific examples of active ester compounds include aromatic esters obtained by condensation reaction between aromatic carboxylic acids and phenolic hydroxyl groups. Among them, aromatic esters obtained by condensation reaction between aromatic carboxylic acids and phenolic hydroxyl groups using a mixture of raw materials: an aromatic carboxylic acid component in which 2 to 4 hydrogen atoms of the aromatic ring of benzene, naphthalene, biphenyl, diphenylpropane, diphenylmethane, diphenylether, diphenylsulfonic acid, etc. are substituted with carboxyl groups, a monohydric phenol in which one hydrogen atom of the aromatic ring is substituted with a hydroxyl group, and a polyhydric phenol in which 2 to 4 hydrogen atoms of the aromatic ring are substituted with a hydroxyl group. That is, aromatic esters having structural units derived from the aromatic carboxylic acid component, structural units derived from the monohydric phenol, and structural units derived from the polyhydric phenol are preferred.

Specific examples of active ester compounds include the active ester resin described in JP 2012-246367 A, which has a structure obtained by reacting a phenolic resin having a molecular structure in which phenolic compounds are bonded via alicyclic hydrocarbon groups with an aromatic dicarboxylic acid or its halide and an aromatic monohydroxy compound. As the active ester resin, a compound represented by the following structural formula (1) is preferable.

In structural formula (1), ^R1 is an alkyl group having 1 to 4 carbon atoms; X is a benzene ring, a naphthalene ring, a benzene ring or a naphthalene ring substituted with an alkyl group having 1 to 4 carbon atoms, or a biphenyl group; Y is a benzene ring, a naphthalene ring, or a benzene ring or a naphthalene ring substituted with an alkyl group having 1 to 4 carbon atoms; k is 0 or 1; and n represents the average number of repetitions and is 0.25 to 1.5.

Specific examples of the compound represented by structural formula (1) include the following exemplary compounds (1-1) to (1-10). In the structural formula, t-Bu is a tert-butyl group.

Other specific examples of active ester compounds include the compound represented by the following structural formula (2) and the compound represented by the following structural formula (3), which are described in JP 2014-114352 A.

In structural formula (2), ^R1 and ^R2 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; Z represents an ester-forming structural moiety (z1) selected from the group consisting of a benzoyl group, a naphthoyl group, a benzoyl group or a naphthoyl group substituted with an alkyl group having 1 to 4 carbon atoms, and an acyl group having 2 to 6 carbon atoms, or a hydrogen atom (z2); and at least one of the Z's is an ester-forming structural moiety (z1).

In structural formula (3), ^R1 and ^R2 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; Z represents an ester-forming structural moiety (z1) selected from the group consisting of a benzoyl group, a naphthoyl group, a benzoyl group or a naphthoyl group substituted with an alkyl group having 1 to 4 carbon atoms, and an acyl group having 2 to 6 carbon atoms, or a hydrogen atom (z2); and at least one of Z's is an ester-forming structural moiety (z1).

Specific examples of compounds represented by structural formula (2) include the following exemplary compounds (2-1) to (2-6).

Specific examples of compounds represented by structural formula (3) include the following exemplary compounds (3-1) to (3-6).

Commercially available products may be used as the active ester compound. Commercially available products of the active ester compound include "EXB9451", "EXB9460", "EXB9460S", and "HPC-8000-65T" (manufactured by DIC Corporation) as active ester compounds containing a dicyclopentadiene-type diphenol structure; "EXB9416-70BK", "EXB-8", and "EXB-9425" (manufactured by DIC Corporation) as active ester compounds containing an aromatic structure; "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester compound containing an acetylated product of phenol novolac; and "YLH1026" (manufactured by Mitsubishi Chemical Corporation) as an active ester compound containing a benzoylated product of phenol novolac.

The active ester compounds may be used alone or in combination of two or more.

The ester equivalent of the active ester compound is not particularly limited. From the viewpoint of the balance of various properties such as moldability, reflow resistance, and electrical reliability, 150 g/eq to 400 g/eq is preferable, 170 g/eq to 300 g/eq is more preferable, and 200 g/eq to 250 g/eq is even more preferable.

The ester equivalent of the active ester compound is a value measured by a method conforming to JIS K 0070:1992.

From the viewpoint of keeping the dielectric tangent of the cured product low, the equivalent ratio of the epoxy resin to the active ester compound (ester group/epoxy group) is preferably 0.75 or more, more preferably 0.80 or more, and even more preferably 0.85 or more.
From the viewpoint of minimizing the amount of unreacted active ester compound, the equivalent ratio of the epoxy resin to the active ester compound (ester group/epoxy group) is preferably 1.10 or less, more preferably 1.05 or less, and even more preferably 1.03 or less.

The lower limit of the content of the active ester compound relative to the total amount of the curing agent is preferably 85% by mass or more, more preferably 88% by mass or more, and even more preferably 90% by mass or more, from the viewpoint of keeping the dielectric tangent of the cured product low.
The upper limit of the content of the active ester compound relative to the total amount of the curing agent is preferably 98% by mass or less, more preferably 97% by mass or less, and even more preferably 96% by mass or less.

(Nitrogen-containing phenolic compounds)
The curing agents of the present disclosure include nitrogen-containing phenolic compounds.
The nitrogen-containing phenol compound refers to a compound having a group having a nitrogen atom and an aromatic group having a hydroxyl group in one molecule. The nitrogen-containing phenol compound may be used alone or in combination of two or more kinds.

The group having a nitrogen atom is not particularly limited, and may be a nitrogen-containing functional group or a group obtained by removing one hydrogen atom from a nitrogen-containing heterocyclic compound. The nitrogen-containing functional group and the group obtained by removing one hydrogen atom from a nitrogen-containing heterocyclic compound may be used alone or in combination of two or more types in one molecule of the nitrogen-containing phenolic compound.

Examples of the nitrogen-containing functional group include an amino group, an amide group, and a cyano group.
Examples of the group obtained by removing one arbitrary hydrogen atom from a nitrogen-containing heterocyclic compound include groups obtained by removing one arbitrary hydrogen atom from a nitrogen-containing alicyclic compound, a nitrogen-containing aromatic compound, and the like.
Examples of the nitrogen-containing alicyclic compounds include pyrrolidine, piperidine, morpholine, diazabicycloundecene, and diazabicyclononene.
Examples of the nitrogen-containing aromatic compound include pyridine, melamine, diazole compounds (imidazole, pyrazole, etc.), oxadiazole compounds (1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-oxadiazole, etc.), triazine compounds (1,2,3-triazine, 1,2,4-triazine, 1,3,5-triazine, etc.), triazole compounds (1,2,3-triazole, 1,2,4-triazole, etc.), and benzotriazole compounds (1,2,3-benzotriazole, 1,2,4-benzotriazole, etc.).
Of the above, the nitrogen-containing aromatic compound is preferably at least one selected from the group consisting of melamine, triazole compounds, and benzotriazole compounds, from the viewpoint of further improving the adhesion of the cured product to a silicon nitride substrate.

The aromatic group in the aromatic group having a hydroxy group is not particularly limited, and any group in which one hydrogen atom has been removed from a known aromatic compound may be used.
Examples of the aromatic group in the aromatic group having a hydroxy group include groups in which any one hydrogen atom has been removed from an aromatic compound such as benzene, naphthalene, or a triazine compound (1,2,3-triazine, 1,2,4-triazine, 1,3,5-triazine, etc.).
Among the above, the aromatic group in the aromatic group having a hydroxyl group is preferably a group in which one hydrogen atom has been removed from benzene, from the viewpoint of further improving the adhesiveness of the cured product to the silicon nitride substrate, i.e., the aromatic group having a hydroxyl group is preferably a phenol group.

Among the above, the nitrogen-containing phenolic compound is preferably one that contains a nitrogen-containing heterocyclic compound. The nitrogen-containing heterocyclic compound may be contained as a group having a nitrogen atom, or may be contained as an aromatic group in an aromatic group having a hydroxyl group. The nitrogen-containing heterocyclic compound is more preferably one that contains a nitrogen-containing aromatic compound.
When the nitrogen-containing phenol compound contains a nitrogen-containing heterocyclic compound, when an encapsulating resin composition containing this is cured, the adhesion of the cured product to a silicon nitride substrate tends to be further improved.

The number of nitrogen atoms constituting the heterocyclic skeleton in the nitrogen-containing heterocyclic compound is not particularly limited.For example, the nitrogen-containing heterocyclic compound preferably comprises a heterocyclic compound having two or more nitrogen atoms as the atoms constituting the heterocyclic skeleton, and more preferably comprises a heterocyclic compound having three or more nitrogen atoms.
When the nitrogen-containing heterocyclic compound contains the heterocyclic compound having two or more nitrogen atoms, when the encapsulating resin composition containing the heterocyclic compound is cured, the nitrogen atoms in the nitrogen-containing phenolic compound tend to cooperatively interact with the silicon nitride substrate, and therefore the adhesiveness of the cured product to the silicon nitride substrate tends to be improved.

The nitrogen-containing phenol compound may have a substituent.
The position of the substituent in the nitrogen-containing phenol compound is not particularly limited as long as a hydrogen atom other than the hydrogen atom of the hydroxy group in the hydroxy group-containing aromatic group is substituted.
The substituent in the nitrogen-containing phenol compound is not particularly limited, and examples thereof include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms, a heteroaryl group having 5 to 14 carbon atoms, a halogen atom (such as a fluorine atom, an iodine atom, a chlorine atom, etc.), etc. The alkyl group, aralkyl group, and alkoxy group in the substituent may be linear, branched, or cyclic.
When there are two or more substituents in the nitrogen-containing phenol compound, the multiple substituents bonded to adjacent positions may be bonded to each other and may be linked to an aromatic ring in an aromatic group having a hydroxy group, a heterocyclic compound having a nitrogen atom, etc. to form a ring.

The position at which the group having a nitrogen atom and the aromatic group having a hydroxy group are linked is not particularly limited, and may be on a carbon atom or on a nitrogen atom.
For example, when the group having a nitrogen atom is a group obtained by removing one arbitrary hydrogen atom from a benzotriazole compound, the nitrogen-containing phenol compound may have a structure in which the nitrogen atom at the 2nd position of the benzotriazole compound is linked to the carbon atom at the 2nd position on the aromatic group in the aromatic group having a hydroxy group.

The group having a nitrogen atom and the aromatic group having a hydroxyl group may be linked via a linking group, or may be linked directly without a linking group. When the group having a nitrogen atom and the aromatic group having a hydroxyl group are linked via a linking group, the type of linking group is not particularly limited, and examples of the linking group include an alkylene group having 1 to 5 carbon atoms.

The nitrogen-containing phenolic compounds may be synthetic or commercially available.
Commercially available nitrogen-containing phenol compounds include HPM-J3 manufactured by Hitachi Chemical Co., Ltd.; SEESORB709, SEESORB707, SEESORB706, SEESORB704, and the like manufactured by Shipro Chemical Co., Ltd.; Tinuvin 928, and the like manufactured by BASF Japan Ltd.; Cyasorb UV1164 manufactured by Sun Chemical Co., Ltd.; and EP-3980S and LA-31 manufactured by ADEKA Corporation.

The hydroxyl equivalent of the nitrogen-containing phenol compound is preferably 100 g/eq or more, more preferably 110 g/eq to 600 g/eq, and even more preferably 115 g/eq to 550 g/eq.

When the hydroxyl equivalent of the nitrogen-containing phenolic compound is 100 g/eq or more, there tends to be no excessive hydroxyl groups in one molecule of the nitrogen-containing phenolic compound. Therefore, when the encapsulating resin composition is cured, the crosslink density in the cured product does not become excessively high, and the increase in the dielectric tangent tends to be further suppressed.

The content of the nitrogen-containing phenol compound is preferably 15% by mass or less, more preferably 1% by mass to 12% by mass, and even more preferably 3% by mass to 10% by mass, based on the total amount of the curing agent.
When the content of the nitrogen-containing phenol compound is 15 mass% or less relative to the total amount of the curing agent, when the encapsulating resin composition is cured, an increase in the dielectric tangent of the cured product tends to be further suppressed.

The content of the nitrogen-containing phenol compound is preferably 15% by mass or less, more preferably 1% by mass to 12% by mass, and even more preferably 3% by mass to 10% by mass, based on the total amount of the active ester compound.
When the content of the nitrogen-containing phenol compound is 15% by mass or less based on the total amount of the active ester compound, the increase in the dielectric loss tangent of the cured product tends to be suppressed when the encapsulating resin composition is cured, whereas when the content of the nitrogen-containing phenol compound is 1% by mass or more based on the total amount of the active ester compound, the cured product tends to have excellent adhesion to silicon nitride while maintaining the dielectric loss tangent.

(Other hardeners)
The curing agent may contain other curing agents other than the active ester compound and the nitrogen-containing phenol compound. When the other curing agent is contained, the type of the other curing agent is not particularly limited and can be selected according to the desired properties of the encapsulating resin composition. Examples of the other curing agent include a phenol curing agent having no nitrogen atom, an acid anhydride curing agent, a polymercaptan curing agent, a polyaminoamide curing agent, an isocyanate curing agent, and a blocked isocyanate curing agent.

Specific examples of the phenolic hardener not having a nitrogen atom include polyhydric phenolic compounds such as resorcin, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted biphenol; 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, and phenylphenol, and naphthol compounds such as α-naphthol, β-naphthol, and dihydroxynaphthalene, with an aldehyde compound such as formaldehyde, acetaldehyde, and propionaldehyde, under an acidic catalyst; and mixtures of the above phenolic compounds with dimethoxyparaxylene, bis(methoxymethyl)biphenyl, and the like. and the like; aralkyl-type phenolic resins such as phenol aralkyl resins and naphthol aralkyl resins synthesized from the above-mentioned phenolic compounds and the like; paraxylylene-modified phenolic resins and metaxylylene-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 and 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 curing agents may be used alone or in combination of two or more.

The functional group equivalent of other curing agents (hydroxyl group equivalent in the case of phenolic curing agents) is not particularly limited. From the viewpoint of the balance of various properties such as moldability, reflow resistance, and electrical reliability, it is preferably 70 g/eq to 1000 g/eq, and more preferably 80 g/eq to 500 g/eq.

The functional group equivalent of other hardeners (hydroxyl group equivalent in the case of phenolic hardeners) is specified in JIS K
The value is measured by a method conforming to Japanese Patent Application Laid-Open No. 0070:1992.

(Properties of the hardener)
The softening point or melting point of the curing agent is not particularly limited, but is preferably 40° C. to 180° C. from the viewpoint of moldability and reflow resistance, and more preferably 50° C. to 130° C. from the viewpoint of handleability during production of the encapsulating resin composition.

The melting point or softening point of the curing agent is the value measured by the single cylinder rotational viscometer method described in JIS K 7234:1986 and JIS K 7233:1986.

The equivalent ratio of the epoxy resin to all the curing agents (active ester compounds, nitrogen-containing phenolic compounds, and other curing agents), i.e., the ratio of the number of functional groups in the curing agent to the number of functional groups in the epoxy resin (number of functional groups in the curing agent/number of functional groups in the epoxy resin), is not particularly limited. From the viewpoint of keeping the amount of unreacted components low, it is preferably set in the range of 0.5 to 2.0, and more preferably in the range of 0.6 to 1.3. From the viewpoint of moldability and reflow resistance, it is even more preferable to set it in the range of 0.8 to 1.2.

[Inorganic filler]
The encapsulating resin composition of the present disclosure may contain an inorganic filler. The type of inorganic filler is not particularly limited. Specific examples of inorganic materials include fused silica, crystalline silica, glass, alumina, talc, clay, and mica. An inorganic filler having a flame retardant effect may be used. Examples of inorganic fillers having a flame retardant effect include aluminum hydroxide, magnesium hydroxide, composite metal hydroxides such as composite hydroxides of magnesium and zinc, and zinc borate.

Among inorganic fillers, silica such as fused silica is preferred from the viewpoint of reducing the linear expansion coefficient, and alumina is preferred from the viewpoint of high thermal conductivity. One type of inorganic filler may be used alone, or two or more types may be used in combination. Inorganic fillers may be in the form of powder, beads formed by spheroidizing powder, fibers, etc.

When the inorganic filler is particulate, its average particle size is not particularly limited. For example, the average particle size is preferably 0.2 μm to 100 μm, and more preferably 0.5 μm to 50 μm. When the average particle size is 0.2 μm or more, the increase in viscosity of the encapsulating resin composition tends to be more suppressed. When the average particle size is 100 μm or less, the filling property tends to be more improved. The average particle size of the inorganic filler is determined as the volume average particle size (D50) by a laser scattering diffraction method particle size distribution measuring device.

The content of the inorganic filler in the encapsulating resin composition is not particularly limited.
The content of the inorganic filler in the encapsulating resin composition is preferably 60% by volume to 90% by volume, more preferably 65% by volume to 85% by volume, and even more preferably 70% by volume to 80% by volume.
When the content of the inorganic filler in the encapsulating resin composition is 60% by volume or more, the properties of the cured product, such as the thermal expansion coefficient, thermal conductivity, and elastic modulus, tend to be further improved.
When the content of the inorganic filler in the encapsulating resin composition is 90% by volume or less, an increase in viscosity of the encapsulating resin composition is suppressed, and the flowability is improved, tending to result in better moldability.

[Various additives]
In addition to the above-mentioned components, the encapsulating resin composition may contain various additives such as a coupling agent, an ion exchanger, a release agent, a flame retardant, a colorant, a stress relaxation agent, etc. The encapsulating resin composition may contain various additives known in the art as necessary, in addition to the additives exemplified below.

(Coupling Agent)
The encapsulating resin composition may contain a coupling agent. From the viewpoint of increasing the adhesion between the resin component and the inorganic filler, the encapsulating resin composition preferably contains a coupling agent. Examples of the coupling agent include known coupling agents such as silane-based compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, and vinylsilane, titanium-based compounds, aluminum chelate compounds, and aluminum/zirconium-based compounds.

When the encapsulating resin composition contains a coupling agent, the amount of the coupling agent is preferably 0.05 parts by mass to 5 parts by mass, and more preferably 0.1 parts by mass to 2.5 parts by mass, per 100 parts by mass of the inorganic filler. When the amount of the coupling agent is 0.05 parts by mass or more per 100 parts by mass of the inorganic filler, the adhesion to the frame tends to be further improved. When the amount of the coupling agent is 5 parts by mass or less per 100 parts by mass of the inorganic filler, the moldability of the package tends to be further improved.

(Ion exchanger)
The encapsulating resin composition may contain an ion exchanger. The encapsulating resin composition preferably contains an ion exchanger from the viewpoint of improving the moisture resistance and high-temperature storage characteristics of the semiconductor device including the encapsulated element. The ion exchanger is not particularly limited, and a conventionally known ion exchanger can be used. Specifically, hydrotalcite compounds and hydrated oxides of at least one element selected from the group consisting of magnesium, aluminum, titanium, zirconium, and bismuth can be mentioned. The ion exchanger may be used alone or in combination of two or more kinds. Among them, hydrotalcite represented by the following general formula (A) is preferred.

Mg _{(1-X) AlX} (OH) ₂ ( _CO3 ) _{X/ 2.mH2O} ...(A)
(0<X≦0.5, m is a positive number)

When the encapsulating resin composition contains an ion exchanger, the content is not particularly limited as long as it is an amount sufficient to capture ions such as halogen ions, etc. For example, the content is preferably 0.1 to 30 parts by mass, and more preferably 1 to 10 parts by mass, per 100 parts by mass of the resin component (the total amount of the epoxy resin and the curing agent).

(Release agent)
The encapsulating resin composition may contain a mold release agent from the viewpoint of obtaining good releasability from the mold during molding. The mold release agent is not particularly limited, and a conventionally known one may be used. Specific examples include carnauba wax, higher fatty acids such as montanic acid and stearic acid, higher fatty acid metal salts, ester waxes such as montanic acid esters, polyolefin waxes such as oxidized polyethylene and non-oxidized polyethylene, etc. The mold release agent may be used alone or in combination of two or more kinds.

When the encapsulating resin composition contains a release agent, the amount is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the resin component (total amount of epoxy resin and curing agent). When the amount of the release agent is 0.01 parts by mass or more per 100 parts by mass of the resin component, sufficient release properties tend to be obtained. When the amount is 10 parts by mass or less, better adhesion tends to be obtained.

(Flame retardants)
The encapsulating resin composition may contain a flame retardant. The flame retardant is not particularly limited, and a conventionally known flame retardant may be used. Specific examples include organic or inorganic compounds containing halogen atoms, antimony atoms, nitrogen atoms, or phosphorus atoms, metal hydroxides, etc. The flame retardant may be used alone or in combination of two or more.

When the encapsulating resin composition contains a flame retardant, the amount is not particularly limited as long as it is an amount sufficient to obtain the desired flame retardant effect. For example, it is preferably 1 to 30 parts by mass, and more preferably 2 to 20 parts by mass, per 100 parts by mass of the resin component (total amount of epoxy resin and curing agent).

(Coloring Agent)
The encapsulating resin composition may contain a colorant. Examples of the colorant include known colorants such as carbon black, organic dyes, organic pigments, titanium oxide, red lead, and red iron oxide. The content of the colorant can be appropriately selected depending on the purpose. The colorant may be used alone or in combination of two or more kinds.

[Method for preparing encapsulating resin composition]
The method for preparing the encapsulating resin composition is not particularly limited. A typical method is to thoroughly mix the components in a predetermined amount with a mixer or the like, melt-knead them with a mixing roll, an extruder, or the like, cool them, and pulverize them. More specifically, for example, a method is to stir and mix the predetermined amounts of the components described above, knead them with a kneader, roll, extruder, or the like that has been heated to 70°C to 140°C in advance, cool them, and pulverize them.

The encapsulating resin composition is preferably solid at room temperature and normal pressure (e.g., 25°C, atmospheric pressure). When the encapsulating resin composition is solid, the shape is not particularly limited, and examples include powder, granules, and tablets. When the encapsulating resin composition is in tablet form, it is preferable from the viewpoint of handleability that the dimensions and mass are set to be suitable for the molding conditions of the package.

- Semiconductor device -
A semiconductor device according to one embodiment of the present disclosure includes a semiconductor element and a cured product of the encapsulating resin composition according to the present disclosure that encapsulates the semiconductor element.

Examples of the semiconductor device include a semiconductor element (active elements such as semiconductor chips, transistors, diodes, and thyristors, and passive elements such as capacitors, resistors, and coils) mounted on a support member such as a lead frame, a pre-wired tape carrier, a wiring board, glass, a silicon wafer, or an organic substrate, and the resulting element portion is encapsulated with an encapsulating resin composition.
More specifically, a semiconductor element is fixed on a lead frame, and terminals of the semiconductor element, such as bonding pads, and leads are connected by wire bonding, bumps, or the like, and then the semiconductor element is encapsulated by transfer molding or the like using an encapsulating resin composition. These include DIPs (Dual Inline Packages), PLCCs (Plastic Leaded Chip Carriers), QFPs (Quad Flat Packages), SOPs (Small Outline Packages), SOJs (Small Outline J-lead packages), TSOPs (Thin Small Outline Packages), TQFPs (Thin Quad Flat Packages), and the like. Examples of such a semiconductor device include a general resin-sealed IC such as a tape carrier package (TCP); a tape carrier package (TCP) having a structure in which a semiconductor element connected to a tape carrier by bumps is sealed with an encapsulating resin composition; a chip-on-board (COB) module, hybrid IC, multi-chip module, and the like having a structure in which a semiconductor element connected to wiring formed on a support member by wire bonding, flip chip bonding, solder, or the like is sealed with an encapsulating resin composition; and a ball grid array (BGA), chip size package (CSP), and multi-chip package (MCP) having a structure in which a semiconductor element is mounted on the surface of a support member having terminals for wiring board connection formed on the back surface thereof, the semiconductor element is connected to the wiring formed on the support member by bumps or wire bonding, and then the semiconductor element is sealed with an encapsulating resin composition. The encapsulating resin composition can also be suitably used in printed wiring boards.

-Method of manufacturing semiconductor device-
The method for manufacturing the semiconductor device of the present disclosure is not particularly limited, and may include a step of placing a semiconductor element on a support member and a step of encapsulating the semiconductor element with the encapsulating resin composition of the present disclosure.

The method for carrying out each of the above steps is not particularly limited, and can be carried out by a general method. In addition, the type of support member and semiconductor element used in the manufacture of the semiconductor device is not particularly limited, and support members and semiconductor elements commonly used in the manufacture of semiconductor devices can be used.

The method of encapsulating electronic components using the encapsulating resin composition of the present disclosure is not particularly limited and can be selected according to the application. For example, it can be encapsulated by a known molding method such as transfer molding. Examples of electronic component devices include ICs, LSIs, power devices, etc.

The present invention will be described in more detail below based on examples, but the present invention is not limited to the following examples. The materials, amounts used, ratios, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of this disclosure. Note that "parts" means "parts by mass" unless otherwise specified.

- Preparation of encapsulating resin composition -
The components shown below were mixed in the amounts (parts by mass) shown in Table 1 to prepare encapsulating resin compositions of Examples and Comparative Examples.

Epoxy resin 1: biphenyl aralkyl type epoxy resin, epoxy equivalent 275 g/eq (Nippon Kayaku Co., Ltd., product name "NC-3000")
Epoxy resin 2: biphenyl type epoxy resin, epoxy equivalent 192 g/eq (Mitsubishi Chemical Corporation, product name "YX-4000")

Hardener 1: Biphenyl aralkyl type phenolic resin (hydroxyl equivalent 199 g/eq, Air Water Inc., product name "HE200C-10")
Hardener 2: Active ester compound (DIC Corporation, product name "EXB-8")
Curing agent 3: Nitrogen-containing phenol compound (melamine-modified phenolic resin, hydroxyl equivalent 120 g/eq, manufactured by Hitachi Chemical Co., Ltd., product name "HPM-J3", has three nitrogen atoms as atoms constituting a heterocyclic skeleton.)
Curing agent 4: Nitrogen-containing phenol compound (benzotriazole-phenolic compound, hydroxyl equivalent 323 g/eq, manufactured by Shipro Kasei Co., Ltd., product name "SEEORB709", having three nitrogen atoms as atoms constituting a heterocyclic skeleton).
Curing agent 5: Nitrogen-containing phenol compound (benzotriazole-phenolic compound, hydroxyl equivalent 441 g/eq, manufactured by BASF, product name "Tinuvin 928", having three nitrogen atoms as atoms constituting a heterocyclic skeleton).
Curing agent 6: Nitrogen-containing phenol compound (triazole-phenol compound, hydroxyl equivalent 509 g/eq, manufactured by Sun Chemical Co., Ltd., product name "Cyasorb UV1164", having three nitrogen atoms as atoms constituting a heterocyclic skeleton).

Curing accelerator: p-benzoquinone adduct of triphenylphosphine Coupling agent: N-phenyl-3-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., product name "KBM-573")
Release agent: Montan acid ester wax (Clariant Japan Co., Ltd., product name "HW-E")
Colorant: Carbon black (Mitsubishi Chemical Corporation, product name "MA600")
Inorganic filler: Silica filler (Denka Co., Ltd., product name "FB-9454FC", average particle size 18 μm)

[Evaluation of the cured product of the encapsulating resin composition]
The encapsulating resin compositions of each example, which were formulated in the composition ratios shown in Table 1, were evaluated for the following test items. The evaluation results are shown in Table 1 below. The curable resin compositions were molded using a transfer molding machine at a mold temperature of 175°C, a molding pressure of 6.9 MPa, and a curing time of 90 seconds, unless otherwise specified. In addition, post-curing was performed at 175°C for 6 hours, as necessary.

(Dielectric constant and dielectric loss tangent)
The encapsulating resin composition was charged into a transfer molding machine, molded under the conditions of a mold temperature of 180°C, molding pressure of 6.9 MPa, and curing time of 90 seconds, and post-cured at 175°C for 6 hours to obtain a rod-shaped cured product (length 0.8 mm, width 0.6 mm, thickness 90 mm). The cured product was used as a test specimen to measure the relative dielectric constant and dielectric loss tangent at 25±1°C and 20 GHz using a cavity resonator (Kanto Electronics Application Development Co., Ltd., "CP561") and a network analyzer (Keysight Technologies, Inc., "PNA E8364B").

(Hot hardness)
The epoxy resin composition prepared in each example was molded under the above conditions into a disk having a diameter of 50 mm and a thickness of 3 mm, and immediately after molding, the Shore D hardness was measured using a Shore D durometer (Asker, Type D durometer, manufactured by Kobunshi Keiki Co., Ltd.).

(260°C shear adhesive strength (Pd-PPF))
The curable resin composition was molded under the above conditions onto a silicon nitride substrate to have a bottom diameter of 4 mm, a top diameter of 3 mm, and a height of 4 mm, and post-cured under the above conditions.
The shear adhesive strength (MPa) was determined at a shear rate of 50 μm/s using a shear tester (Nordson Advanced Technology Co., Ltd., Series 4000) while maintaining the temperature of the copper plate at 260° C.

As shown in Table 1, the encapsulating resin composition of the embodiment was found to improve adhesion to silicon nitride substrates while maintaining a low dielectric tangent at 20 GHz compared to the encapsulating resin composition of the comparative example.

The present invention relates to a resin composition for transfer molding encapsulation and a semiconductor device.

Claims (8)

Epoxy resin,
a curing agent including an active ester compound and a nitrogen-containing phenolic compound;
An encapsulating resin composition comprising: The encapsulating resin composition according to claim 1, wherein the nitrogen-containing phenol compound has a hydroxyl group equivalent of 100 g/eq or more. The encapsulating resin composition according to claim 1 or 2, wherein the nitrogen-containing phenolic compound includes a nitrogen-containing heterocyclic compound. The encapsulating resin composition according to claim 3, wherein the nitrogen-containing heterocyclic compound includes a heterocyclic compound having two or more nitrogen atoms as atoms constituting the heterocyclic skeleton. The encapsulating resin composition according to any one of claims 1 to 4, wherein the content of the nitrogen-containing phenol compound is 15 mass% or less relative to the total amount of the curing agent. The encapsulating resin composition according to any one of claims 1 to 5, further comprising an inorganic filler. The encapsulating resin composition according to claim 6, wherein the content of the inorganic filler in the encapsulating resin composition is 65% by volume or more. A semiconductor device comprising a semiconductor element and a cured product of the encapsulating resin composition according to any one of claims 1 to 7, which encapsulates the semiconductor element.