JP7540164B2 - Encapsulating resin composition and electronic device - Google Patents

Description

The present invention relates to an encapsulating resin composition and an electronic device. More specifically, the present invention relates to an encapsulating resin composition having a specific composition, and an electronic device having an encapsulant that is a cured product of the composition.

Various types of encapsulating resin compositions containing epoxy resins are known, primarily for encapsulating electronic devices.

As communication information becomes larger and more diverse, communication speeds are increasing for printed circuit boards for communication base stations, servers, routers, and the like. In order to keep up with the increased communication speeds, signals need to be made higher frequency.

On the other hand, reducing transmission loss is important to ensure signal quality. Transmission loss is mainly classified into dielectric loss caused by the resin used in electronic devices and conductor loss caused by the conductor. The former dielectric loss tends to decrease as the dielectric constant and dielectric loss tangent of the resin used in electronic devices become smaller.

As a material capable of achieving low dielectric constant and low dielectric tangent, for example, Patent Document 1 discloses a technology in which an active ester compound obtained by reacting dicyclopentadiene-type phenolic resin with benzoyl chloride and bis(chlorocarbonyl)benzene is used as a curing agent for epoxy resin.

JP 2004-169021 A

However, conventional encapsulating resin compositions such as those described in Patent Document 1 have not been able to adequately meet the increasing frequency demands of recent years.

After extensive research, the inventors discovered that even with an encapsulating resin composition containing an epoxy resin, a curing agent, an inorganic filler, and a colorant, dielectric loss at high frequencies may be reduced in some cases and not in other cases. As a result of further research, they devised a new index for the encapsulating resin composition and found that dielectric loss at high frequencies can be reduced by the encapsulating resin composition satisfying this index, thereby completing the present invention.

According to the present invention,
Epoxy resin,
A hardener;
An inorganic filler;
A colorant;
and satisfying the following conditions:
Condition: the encapsulating resin composition is used and cured at 175° C. for 2 minutes, and the cured product has a dielectric loss tangent (Tan δ) at 5 GHz and 23° C. of less than 0.008.

Further, according to the present invention,
An electronic device comprising an electronic component and a sealant that seals the electronic component,
There is provided an electronic device, wherein the encapsulant is formed from a cured product of the encapsulating resin composition.

According to the present invention, the dielectric tangent of the cured product of the encapsulating resin composition can be reduced.

FIG. 1 is a cross-sectional view illustrating an example of a structure of an electronic device.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
In all drawings, similar components are given similar symbols and descriptions thereof are omitted where appropriate.
In order to avoid complexity, (i) when there are multiple identical components in the same drawing, only one of them will be given a reference symbol, and not all of them will be given a reference symbol, and (ii) particularly in Figure 2 and subsequent figures, components similar to those in Figure 1 will not be given a reference symbol again.
All drawings are for illustrative purposes only. The shapes and dimensional ratios of each component in the drawings do not necessarily correspond to the actual objects.

In this specification, the term "approximately" means that a range taking into consideration manufacturing tolerances, assembly variations, and the like, is included unless otherwise specified explicitly.
In this specification, the expression "a to b" in the description of a numerical range means from a to b, unless otherwise specified. For example, "1 to 5% by mass" means "1% by mass to 5% by mass."

In the description of groups (atomic groups) in this specification, when a notation does not specify whether the group is substituted or unsubstituted, the notation includes both groups having no substituents and groups having a substituent. For example, an "alkyl group" includes not only an alkyl group having no substituents (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).
In this specification, the term "(meth)acrylic" refers to a concept that includes both acrylic and methacrylic. The same applies to similar terms such as "(meth)acrylate."
In this specification, unless otherwise specified, the term "organic group" refers to an atomic group obtained by removing one or more hydrogen atoms from an organic compound. For example, a "monovalent organic group" refers to an atomic group obtained by removing one hydrogen atom from any organic compound.
In this specification, the term "electronic device" is used to include elements, devices, final products, etc. to which electronic engineering technology is applied, such as semiconductor chips, semiconductor elements, printed wiring boards, electric circuit display devices, information and communication terminals, light-emitting diodes, physical batteries, and chemical batteries.

<Sealing resin composition>
The encapsulating resin composition of the present embodiment contains an epoxy resin, a curing agent, an inorganic filler, and a colorant, and satisfies the following conditions.
Condition: the encapsulating resin composition is used and cured at 175° C. for 2 minutes, and the cured product has a dielectric loss tangent (Tan δ) at 5 GHz and 23° C. of less than 0.008.
This makes it possible to reduce the dielectric tangent of the cured product of the encapsulating resin composition to a greater extent.

Here, according to the findings of the present inventors, the dielectric loss tangent tends to increase as the amount of hydroxyl groups contained in the encapsulating resin composition increases, so reducing the amount of hydroxyl groups in the encapsulating resin composition is effective in reducing the dielectric loss tangent. Conventionally, carbon black has been included in the encapsulating resin composition to obtain a black molded body, but this generates electrical conductivity, making it difficult to achieve a low dielectric loss tangent. Therefore, in the encapsulating resin composition of this embodiment, a combination of the following known methods can be used to obtain an encapsulating resin composition that satisfies the above conditions, and it is believed that satisfying such conditions can achieve a low dielectric loss tangent. The encapsulating resin composition of this embodiment is obtained by appropriately combining known methods with the entire encapsulating resin composition, rather than relying on the contribution of only a specific component.
The epoxy resin, hardener, inorganic filler, and colorant of the encapsulating resin composition are appropriately combined according to their respective properties.
The contents of the epoxy resin, the curing agent, the inorganic filler and the colorant in the encapsulating resin composition are adjusted according to the combination.
For example, it is possible to select an epoxy resin or a curing agent with a small amount of hydroxyl groups, to perform a surface treatment in advance when an inorganic filler having hydroxyl groups on the surface is selected, to adjust the content of the colorant depending on the type of colorant, etc. However, such descriptions are merely examples, and the encapsulating resin composition of the present embodiment is not limited thereto.
Each component will be described in detail below.

[Epoxy resin]
The encapsulating resin composition of the present embodiment contains an epoxy resin.
Specifically, the epoxy resin may be a monomer, oligomer, or polymer having two or more epoxy groups in one molecule. The molecular weight and molecular structure of the epoxy resin are not particularly limited.

As the epoxy resin used in the encapsulating resin composition of the present embodiment, any epoxy resin that is generally used in epoxy encapsulating resin compositions for semiconductor encapsulation can be used. Examples of these include phenols including phenol novolac type epoxy resins and orthocresol novolac type epoxy resins; epoxy resins obtained by epoxidizing novolac resins obtained by condensing or co-condensing phenols such as cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F, etc. and/or naphthols such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc. with compounds having an aldehyde group such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, salicylaldehyde, etc. under an acidic catalyst; diglycidyl ethers of bisphenol A, bisphenol F, bisphenol S, bisphenol A/D, etc.; biphenyl type epoxy resins which are diglycidyl ethers of alkyl-substituted or unsubstituted biphenols; epoxidized products of phenol aralkyl resins synthesized from phenols and/or naphthols and dimethoxy-para-xylene or bis(methoxymethyl)biphenyl; stilbenes, etc. glycidyl ester type epoxy resins obtained by reacting epichlorohydrin with polybasic acids such as diaminodiphenylmethane and isocyanuric acid; dicyclopentadiene type epoxy resins which are epoxidized products of co-condensation resins of dicyclopentadiene and phenols; epoxy resins having a naphthalene ring; triphenolmethane type epoxy resins; trimethylolpropane type epoxy resins; trishydroxyphenylmethane type epoxy resins; biphenol type epoxy resins; terpene-modified epoxy resins; linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid; alicyclic epoxy resins; and epoxy resins modified with silicone, acrylonitrile, butadiene, isoprene-based rubber, polyamide-based resin, or the like. These may be used alone or in combination of two or more.
Among these, it is preferable to use one or more selected from the group consisting of novolac type epoxy resins, biphenyl type epoxy resins, phenol aralkyl resins, trishydroxyphenylmethane type epoxy resins, and biphenol type epoxy resins.

The encapsulating resin composition may contain only one type of epoxy resin, or may contain two or more types of epoxy resin.
The content of the epoxy resin is, for example, 2 mass % or more, preferably 3 mass % or more, and more preferably 4 mass % or more, based on the entire encapsulating resin composition, from the viewpoint of obtaining suitable fluidity during molding and improving filling property and moldability.
From another viewpoint, from the viewpoint of improving the insulating properties of an encapsulating material obtained using the encapsulating resin composition, the content of the epoxy resin is, for example, 40 mass % or less, preferably 30 mass % or less, more preferably 15 mass % or less, and even more preferably 10 mass % or less, relative to the entire encapsulating resin composition.

[Curing agent]
Examples of the curing agent include amine compounds such as diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, imidazole, BF3-amine complex, and guanidine derivatives; amide compounds such as dicyandiamide and polyamide resins synthesized from a dimer of linoleic acid and ethylenediamine; acid anhydrides such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride; phenol novolac resins, cresol novolac resins, and aromatic hydrocarbon formaldehyde resins. Examples of polyhydric phenol compounds include modified phenol resins, dicyclopentadiene phenol addition type resins, phenol aralkyl resins, naphthol aralkyl resins, trimethylolmethane resins, tetraphenylolethane resins, naphthol novolak resins, naphthol-phenol co-condensed novolak resins, naphthol-cresol co-condensed novolak resins, biphenyl-modified phenol resins (polyhydric phenol compounds in which phenol nuclei are linked via bismethylene groups), biphenyl-modified naphthol resins (polyhydric naphthol compounds in which phenol nuclei are linked via bismethylene groups), and aminotriazine-modified phenol resins (polyhydric phenol compounds in which phenol nuclei are linked via melamine, benzoguanamine, etc.). These may be used alone or in combination of two or more.
From the viewpoint of realizing a highly low dielectric tangent, it is desirable to select the type of curing agent according to the type of epoxy resin.

The content of the curing agent is preferably 1 mass % or more, more preferably 2 mass % or more, and even more preferably 3 mass % or more, based on the total mass of the composition, from the viewpoint of improving excellent fluidity, filling property, moldability, and the like when sealing an electronic device.
On the other hand, from the viewpoint of improving the moisture resistance reliability and reflow resistance of electronic devices, the content of the curing agent is preferably 25 mass % or less, more preferably 15 mass % or less, and even more preferably 10 mass % or less, based on the total mass of the composition.

It is preferable to adjust the amount of epoxy resin and curing agent so that the equivalent ratio is an appropriate value. By appropriately adjusting the equivalent ratio, it becomes easier to realize a low dielectric tangent, and there is a tendency to obtain effects such as better moldability and further improved reliability when used as a sealing material.
For example, when the curing agent is a phenol-based curing agent, the equivalent ratio between the epoxy resin and the curing agent, i.e., the ratio of the number of moles of epoxy groups in the epoxy resin/the number of moles of phenolic hydroxyl groups in the curing agent, is, for example, 0.5 to 2, preferably 0.6 to 1.8, and more preferably 0.8 to 1.5.
When the curing agent is an amine-based curing agent, since the amino group (-NH ₂ ) has two active hydrogens, the ratio of the number of moles of epoxy groups in the epoxy resin to the number of moles of amino groups in the curing agent is, for example, 1 to 4, preferably 1.2 to 3.6, and more preferably 1.6 to 3.

[Inorganic filler]
The encapsulating resin composition of the present embodiment contains an inorganic filler. As the inorganic filler, any inorganic filler that is generally used in encapsulating resin compositions for encapsulating electronic devices can be used.

Specific examples of inorganic fillers include silica (silicon dioxide) such as fused crushed silica, fused spherical silica, crystalline silica, and secondary agglomerated silica; alumina; titanium white; aluminum hydroxide; talc; clay; mica; and glass fiber. Among these, silica is preferred, and fused spherical silica is particularly preferred. In addition, from the viewpoint of achieving a highly low dielectric tangent, the filler may be surface-treated.

The particle shape of the inorganic filler is preferably approximately spherical.
The median diameter of the inorganic filler is not particularly limited. It is typically 0.01 to 100 μm, preferably 0.05 to 50 μm, and more preferably 0.5 to 30 μm. By having an appropriate median diameter, it is possible to further improve the flowability during molding, and to increase the filling ability of the composition into narrow spaces of electronic devices.
In addition, the particle size distribution may have peaks between 0.01 and 10 μm and between 10 and 100 μm, respectively. In other words, inorganic fillers having different average particle sizes may be mixed and used.

The content of the inorganic filler is preferably 60% by mass or more, more preferably 70% by mass or more, and further preferably 80% by mass or more, based on the entire encapsulating resin composition.
In addition, from the viewpoint of more effectively improving the fluidity and filling property of the encapsulating resin composition during molding, the content of the inorganic filler is preferably 95 mass % or less, and more preferably 90 mass % or less, based on the entire encapsulating resin composition.
By appropriately adjusting the content of the inorganic filler, it is possible to achieve a highly low dielectric tangent while also obtaining effects such as further improving the low moisture absorption and low thermal expansion of the encapsulant, further improving the moisture resistance reliability and reflow resistance of the resulting electronic device, and further improving the fluidity and filling properties during molding.

[Coloring agent]
The colorant is used to give the final sealing material a desired color while reducing the dielectric loss tangent. Examples of the colorant include orange dye, yellow dye, black dye, carbon black, and titanium oxide. Among them, it is preferable to include at least one of black titanium oxide and black dye from the viewpoint of obtaining a suitable black color while reducing the dielectric loss tangent.
The black titanium oxide more preferably contains a compound represented by TiO _x (wherein x is 1 or more and less than 2).
The black dye may be one or more selected from the group consisting of anthraquinone dyes, azine dyes, azo dyes, disazo dyes, and chromium complex dyes. These dyes are preferred because they have a relatively high decomposition temperature, so that deterioration or discoloration during curing is suppressed, and dyes with less halogen-based impurities that are undesirable for electronic materials are easily available.

Commercially available black dyes (d1) include NUBIAN BLACK PC-5857 (anthraquinone type, Orient Chemical Industry Co., Ltd.), SEP-L-0040 (anthraquinone type, Orient Chemical Industry Co., Ltd.), NUBIAN BLACK PC-8550 (mixture of anthraquinone type and azine type, Orient Chemical Industry Co., Ltd.), SOL-L-0693 (mixture of anthraquinone type and azo type, Orient Chemical Industry Co., Ltd.), VALIFAST BLACK 1821 (azine type, Orient Chemical Industry Co., Ltd.), OIL BLACK BS (azine type, Orient Chemical Industry Co., Ltd.), ORIPACS B-35 (azine type, Orient Chemical Industry Co., Ltd.), OIL BLACK 860 (disazo type, Orient Chemical Industry Co., Ltd.), OIL BLACK Examples of the VALIFAST BLACK 3830 include VALIFAST BLACK 3877 (chromium complex salt, Orient Chemical Industry Co., Ltd.), and the like.
Here, "NUBIAN", "ORIPACS" and "VARIFAST" are registered trademarks of Orient Chemical Industries Co., Ltd.

The content of the colorant is preferably 0.01 mass % or more and 3.0 mass % or less, more preferably 0.05 mass % or more and 2.0 mass % or less, and even more preferably 0.1 mass % or more and 1.0 mass % or less, based on the entire encapsulating resin composition.
By setting the content of the colorant to be equal to or greater than the above lower limit, the sealing body can be easily given a desired color, whereas by setting the content of the colorant to be equal to or less than the above upper limit, a low dielectric tangent can be achieved while obtaining a desired color.
However, when carbon black is contained as a colorant, in order to suppress an increase in the dielectric tangent, the content is preferably less than 0.1 mass % based on the entire encapsulating resin composition, and it is more preferable that carbon black is substantially not contained.

[Active ester resin]
The encapsulating resin composition of the present embodiment may further include an active ester resin. The active ester resin has an active ester group represented by the following formula (1). In the curing reaction between the epoxy resin and the active ester resin, the active ester group of the active ester resin reacts with the epoxy group of the epoxy resin to generate a secondary hydroxyl group. This secondary hydroxyl group is blocked by the ester residue of the active ester resin. Therefore, the dielectric constant and dielectric loss tangent of the cured product are reduced.

(In formula (1), A is a substituted or unsubstituted arylene group linked via an aliphatic cyclic hydrocarbon group, Ar' is a substituted or unsubstituted aryl group, k is the average value of the repeating units and is in the range of 0.25 to 3.5, and B is a structure represented by the following formula (2).)

(In formula (2), Ar is a substituted or unsubstituted arylene group, and Y is a single bond, a linear or cyclic alkylene group having 2 to 6 carbon atoms, an ether bond, a carbonyl group, a carbonyloxy group, a sulfide group, or a sulfone group.)

The structure represented by the above formula (2) is preferably at least one selected from the following formulas (2-1) to (2-6).

In formulas (2-1) to (2-6),
R ¹ 's each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, or an aralkyl group;
^R2 is independently any one of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a phenyl group; X is any one of a linear alkylene group having 2 to 6 carbon atoms, an ether bond, a carbonyl group, a carbonyloxy group, a sulfide group, and a sulfone group;
n and p are integers from 1 to 4.

Since the structures represented by the above formulas (2-1) to (2-6) are all highly oriented structures, when an active ester resin containing such an active ester resin is used, the resulting cured product of the encapsulating resin composition has a low dielectric constant and a low dielectric loss tangent, and is excellent in adhesion to metals, and therefore can be suitably used as a semiconductor encapsulating material. Among these, from the viewpoint of low dielectric constant and low dielectric loss tangent, an active ester resin having a structure represented by formula (2-3) or (2-5) is preferred, and an active ester resin having a structure in which X in formula (2-3) is an ether bond, or a structure in which two carbonyloxy groups are at the 4,4'-position in formula (2-5) is more preferred. In addition, it is preferable that all R ^1s in each formula are hydrogen atoms.

In formula (1), "Ar'" is an aryl group, and may be, for example, a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 3,5-xylyl group, an o-biphenyl group, an m-biphenyl group, a p-biphenyl group, a 2-benzylphenyl group, a 4-benzylphenyl group, a 4-(α-cumyl)phenyl group, a 1-naphthyl group, or a 2-naphthyl group. Among these, a 1-naphthyl group or a 2-naphthyl group is preferable, since a cured product having a particularly low dielectric constant and dielectric dissipation factor can be obtained.

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

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

On the other hand, examples of the phenolic compound include phenol, cresol, xylenol, ethylphenol, isopropylphenol, butylphenol, octylphenol, nonylphenol, vinylphenol, isopropenylphenol, allylphenol, phenylphenol, benzylphenol, chlorophenol, bromophenol, 1-naphthol, 2-naphthol, 1,4-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, etc., and each may be used alone or two or more types may be used in combination. Among these, phenol is preferred because it is highly curable and becomes an active ester resin with excellent dielectric properties in the cured product.

In a preferred embodiment, "A" in the active ester resin represented by formula (1) has a structure represented by the following formula (3). The encapsulating resin composition containing the active ester resin in which "A" in formula (1) has the following structure has a cured product with a low dielectric constant and a low dielectric tangent, and has excellent adhesion to the insert product.

In formula (3), ^R3 is independently any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, and an aralkyl group, l is 0 or 1, and m is an integer of 1 or more.

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

(In formula (1-1), R ¹ and R ³ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, or an aralkyl group; Z represents a phenyl group, a naphthyl group, or a phenyl group or naphthyl group having 1 to 3 alkyl groups having 1 to 4 carbon atoms on the aromatic nucleus; l represents 0 or 1; and k represents the average of the repeating units and is 0.25 to 3.5.)

(In formula (1-2), R ¹ and R ³ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, or an aralkyl group; Z represents a phenyl group, a naphthyl group, or a phenyl group or naphthyl group having 1 to 3 alkyl groups having 1 to 4 carbon atoms on the aromatic nucleus; l is 0 or 1; and k is the average of the repeating units and is 0.25 to 3.5.)

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

The reaction ratio of the phenolic compound (a), aromatic nucleus-containing dicarboxylic acid or its halide (b), and aromatic monohydroxy compound (c) can be adjusted appropriately according to the desired molecular design. Among them, since an active ester resin with higher curing properties can be obtained, it is preferable to use each raw material in a ratio such that the phenolic hydroxyl group of the phenolic compound (a) is in the range of 0.25 to 0.90 moles and the hydroxyl group of the aromatic monohydroxy compound (c) is in the range of 0.10 to 0.75 moles per 1 mole of the total of carboxyl groups or acid halide groups of the aromatic nucleus-containing dicarboxylic acid or its halide (b), and it is more preferable to use each raw material in a ratio such that the phenolic hydroxyl group of the phenolic compound (a) is in the range of 0.50 to 0.75 moles and the hydroxyl group of the aromatic monohydroxy compound (c) is in the range of 0.25 to 0.50 moles.

In addition, the functional group equivalent of the active ester resin, when the total number of arylcarbonyloxy groups and phenolic hydroxyl groups in the resin structure is taken as the number of functional groups of the resin, is preferably in the range of 200 g/eq to 230 g/eq, more preferably in the range of 210 g/eq to 220 g/eq, since this gives a cured product with excellent curability and low dielectric constant and dielectric loss tangent.

When the encapsulating resin composition of this embodiment contains an active ester resin, the amount of the active ester resin and the epoxy resin is preferably such that the epoxy groups in the epoxy resin are 0.8 to 1.2 equivalents per equivalent of the total active groups in the active ester resin, since this gives a cured product with excellent curing properties and low dielectric constant and dielectric tangent. Here, the active groups in the active ester resin refer to the arylcarbonyloxy groups and phenolic hydroxyl groups in the resin structure.

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

[Other ingredients]
The encapsulating resin composition of the present embodiment may contain other components that do not fall under any of the above. Specific examples of other components include other thermosetting resins, curing accelerators, coupling agents, mold release agents, ion scavengers, flame retardants, antioxidants, and stress reducing agents. When the encapsulating resin composition contains other components, it may contain only one type, or may contain two or more types.

The other thermosetting resins mentioned above include cyanate ester compounds, vinylbenzyl compounds, acrylic compounds, maleimide compounds, copolymers of styrene and maleic anhydride, etc. Among them, it is preferable to use acrylic compounds because the resulting encapsulating resin composition has good fluidity. When using the other thermosetting resins mentioned above, there is no particular restriction on the amount used as long as it does not inhibit the effects of the present invention, but it is preferable that the amount is in the range of 1% by mass to 50% by mass based on the total solid content of the encapsulating resin composition.

Examples of the curing accelerator include phosphorus atom-containing compounds such as organic phosphines, tetra-substituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, and adducts of phosphonium compounds and silane compounds; and nitrogen atom-containing compounds such as amidines or tertiary amines such as 1,8-diazabicyclo[5.4.0]-7-undecene, benzyldimethylamine, and 2-methylimidazole, and quaternary salts of amidines or amines.
Among these, from the viewpoint of improving the curability, phosphorus atom-containing compounds are preferred.Moreover, from the viewpoint of improving the balance between moldability and curability, it is more preferred to include compounds having latency, such as tetra-substituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, and adducts of phosphonium compounds and silane compounds.
When a curing accelerator is used, the amount thereof is, taking into consideration the balance with other components, etc., preferably 0.01 mass % or more, and more preferably 0.05 mass % or more, and preferably 2.0 mass % or less, and more preferably 1.0 mass % or less, based on the entire encapsulating resin composition.

Examples of the coupling agent include known coupling agents such as aminosilanes such as epoxysilane, mercaptosilane, and phenylaminosilane; various silane-based compounds such as alkylsilane, ureidosilane, vinylsilane, and methacrylsilane; titanium-based compounds; aluminum chelates; and aluminum/zirconium-based compounds.
Among these, it is more preferable to contain an epoxy silane or an amino silane, and it is even more preferable to contain a secondary amino silane, from the viewpoint of flowability, etc. A specific example of a preferable coupling agent is phenylaminopropyltrimethoxysilane.

When the above coupling agent is used, the content of the coupling agent is, taking into consideration the balance with other components, preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and preferably 2.0% by mass or less, more preferably 1.0% by mass or less, based on the total encapsulating resin composition.

Examples of the release agent include natural waxes such as carnauba wax, synthetic waxes such as oxidized polyethylene wax and montanic acid ester wax, higher fatty acids such as zinc stearate and metal salts thereof, and paraffin.
When a release agent is used, the content thereof, taking into consideration the balance with other components, etc., is preferably such that the lower limit is 0.01 mass % or more, more preferably 0.05 mass % or more, and the upper limit is preferably 2.0 mass % or less, more preferably 1.0 mass % or less, based on the entire encapsulating resin composition.

An example of the ion scavenger is hydrotalcite.
When an ion scavenger is used, the content of the ion scavenger in the encapsulating resin composition, from the viewpoint of improving the reliability of the electronic device, is preferably such that the lower limit is 0.03 mass % or more, more preferably 0.05 mass % or more, and the upper limit is preferably 2.0 mass % or less, more preferably 1.0 mass % or less, based on the entire encapsulating resin composition.

Examples of the flame retardant include aluminum hydroxide, magnesium hydroxide, zinc borate, zinc molybdate, and phosphazene.
When a flame retardant is used, the content of the flame retardant in the encapsulating resin composition is, for example, 0.1 to 20 mass %, preferably 1 to 15 mass %, and more preferably 3 to 10 mass %, based on the entire encapsulating resin composition, from the viewpoint of a balance between improving flame retardancy and other performance properties.

Examples of the above-mentioned low stress agent include silicone oil, silicone rubber, and carboxyl-terminated butadiene acrylonitrile rubber.
When a low stress agent is used, the content of the low stress agent in the encapsulating resin composition is, for example, 0.1 to 5 mass %, preferably 0.15 to 3 mass %, and more preferably 0.2 to 1 mass %, based on the entire encapsulating resin composition in terms of balance with other performances.

Examples of the antioxidant include hindered phenol compounds, hindered amine compounds, and thioether compounds.
When an antioxidant is used, the content of the antioxidant in the encapsulating resin composition is, for example, 0.1 to 5 mass %, preferably 0.15 to 3 mass %, and more preferably 0.2 to 1 mass %, based on the entire encapsulating resin composition in terms of balance with other performances.

[Properties of the encapsulating resin composition]
The shape of the encapsulating resin composition of the present embodiment is not particularly limited, and examples of the shape include particles, granules, tablets, and sheets.
When the encapsulating resin composition is in a tablet form, the encapsulating resin composition can be molded, for example, by a transfer molding method. When the encapsulating resin composition is in a powder form, the encapsulating resin composition can be molded, for example, by a compression molding method. Here, the encapsulating resin composition being in a powder form refers to the case where the encapsulating resin composition is in either a powder form or a granular form.

The encapsulating resin composition of the present embodiment has a thermal conductivity of 2 W/mK or more and 50 W/mK or less, as calculated by the following procedure.
Procedure: A molded body (1.0×1.0 mm, thickness 1.0 mm) of the encapsulating resin composition is produced under conditions of a mold temperature of 175° C., an injection pressure of 6.9 MPa, and a curing time of 120 seconds, and then post-cured at 175° C. for 2 hours to obtain a test piece. Using the obtained test piece, the thermal diffusivity is measured by a laser flash method, and further, the specific gravity and specific heat are measured, and the thermal conductivity in the thickness direction of the test piece is calculated from the obtained measured values.
This makes it possible to reduce the dielectric tangent more stably.

That is, by controlling the thermal conductivity measured and calculated under predetermined conditions to within a range of 0.1 W/mK or more and 20 W/mK or less, heat dissipation suitable for the application of the encapsulating resin composition can be obtained. The thermal conductivity is preferably 0.2 W/mK or more, more preferably 0.5 W/mK or more. On the other hand, the thermal conductivity is preferably 15 W/mK or less, more preferably 8 W/mK or less, even more preferably 2 W/mK or less, and particularly preferably 1 W/mK or less.
By setting the thermal conductivity to be equal to or higher than the lower limit, the heat dissipation property is improved while maintaining a low dielectric tangent, whereas by setting the thermal conductivity to be equal to or lower than the upper limit, the production stability is improved.

In this embodiment, the thermal conductivity can be achieved by selecting the material or by devising a manufacturing method. For example, the curing agent can be selected according to the type of epoxy resin, the type of inorganic filler can be selected, the content can be adjusted, two or more types of particles with different average particle sizes can be used as the inorganic filler, or the kneading conditions can be controlled during the manufacture of the encapsulating resin composition. However, the encapsulating resin composition of this embodiment is not limited to such materials or manufacturing methods.

[Cured product]
In addition, it is preferable that the cured product of the encapsulating resin composition of the present embodiment (molding temperature 175° C., curing time 100 seconds, molding pressure 8 MPa) has an L ^* value of 24 to 30, an a ^* value of −2.0 to −0.1, and a b ^* value of −5.0 to −2.5 in the L ^* a ^* b ^* color coordinates.
By designing the encapsulating resin composition so that the L ^* , a ^* and b ^* of the cured product are within the above numerical ranges, it is possible to reduce the dielectric properties while obtaining a color (blackness) similar to that of conventional encapsulating resin compositions containing carbon black.
The values of L ^* , a ^* and b ^* can be controlled by known methods, for example, by selecting the type of colorant or adjusting the content.

Here, the values of L ^* , a ^* , and b ^* are values according to the definition of the Commission Internationale de l'Eclairage (CIE) in 1976. L ^* , a ^* , and b ^* can be measured using a commercially available colorimeter.

[Method of producing encapsulating resin composition]
The method for producing the encapsulating resin composition of the present embodiment is not particularly limited.
For example, the above-mentioned components are mixed by a known means, melt-kneaded in a kneading machine such as a roll, a kneader or an extruder, cooled, and then pulverized to obtain the toner.
If necessary, the powder may be compressed into tablets.
If necessary, after pulverization, the resin composition may be formed into a sheet shape by, for example, vacuum lamination or compression molding. Alternatively, the encapsulating resin composition of the present embodiment may be dissolved in an organic solvent and used as a liquid encapsulating material. In this case, the liquid encapsulating resin composition may be thinly applied onto a plate or film, and the organic solvent may be evaporated under conditions that do not allow the resin curing reaction to proceed very much, to obtain a sheet or film-like material.
If necessary, the degree of dispersion, flowability, etc. of the resulting encapsulating resin composition may be adjusted.

<Semiconductor Device>
Next, the semiconductor device of this embodiment will be described. The semiconductor device of this embodiment includes an electronic component and an encapsulant that encapsulates the electronic component, and the encapsulant is composed of a cured product of the encapsulating resin composition described above. That is, the semiconductor device is obtained by encapsulating a semiconductor element with the encapsulating resin composition described above.
Examples of such semiconductor devices include semiconductor devices in which elements such as active elements such as semiconductor chips, transistors, diodes, and thyristors, and passive elements such as capacitors, resistors, and coils are mounted on a supporting member such as a copper lead frame, and necessary parts are encapsulated with the epoxy encapsulating resin composition for semiconductor encapsulation of the present invention. Examples of such semiconductor devices include general resin-sealed ICs such as DIP (Dual Inline Package), PLCC (Plastic Leaded Chip Carrier), QFP (Quad Flat Package), SOP (Small Outline Package), SOJ (Small Outline J-lead package), TSOP (Thin Small Outline Package), and TQFP (Thin Quad Flat Package), which are produced by fixing a semiconductor element onto a copper lead frame, connecting the terminal portion of the element, such as a bonding pad, and the lead portion by wire bonding or bumps, and then sealing the semiconductor element by transfer molding or the like using the epoxy encapsulating resin composition for semiconductor encapsulation of the present invention. Another example is a semiconductor package in which semiconductor chips are stacked in multiple stages, such as an MCP (Multi Chip Stacked Package).

Figure 1 is a diagram showing the cross-sectional structure of an example of a semiconductor device using the encapsulating resin composition according to the present invention. In Figure 1, a semiconductor element 1 is stacked in two stages and fixed on a die pad 3 via a hardened die bond material 2. The electrode pads of the semiconductor element 1 are connected to a lead frame 5 by gold wires 4. The semiconductor element 1 is encapsulated with an encapsulant 6 made of a hardened product of the above-mentioned encapsulating resin composition. Since the semiconductor element 1 is encapsulated with the hardened product of the above-mentioned encapsulating resin composition, which has excellent dielectric properties and excellent adhesion to the insert product, a semiconductor device with excellent reliability can be obtained.

The most common method for encapsulating elements using the encapsulating resin composition of the present invention is low-pressure transfer molding, but injection molding, compression molding, etc. may also be used. When the encapsulating resin composition is in a liquid or paste form at room temperature, methods such as a dispense method, a casting method, and a printing method may be used.

In addition to the general sealing method of directly sealing the element with resin, there is also a hollow package method in which the sealing resin composition does not come into direct contact with the element, and the resin composition can also be suitably used as a sealing resin composition for hollow packages.

Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of the present invention are included in the present invention.
Below, examples of reference forms are given.
1. An epoxy resin;
A hardener;
An inorganic filler;
A colorant;
and satisfying the following conditions:
Condition: the encapsulating resin composition is used and cured at 175° C. for 2 minutes, and the cured product has a dielectric loss tangent at 5 GHz and 23° C. of less than 0.008.
2. The encapsulating resin composition according to 1., wherein the content of the colorant is 0.01% by mass or more and 3.0% by mass or less with respect to the entire encapsulating resin composition.
3. The encapsulating resin composition according to 1. or 2., wherein the colorant contains at least one of black titanium oxide and a black dye.
4. The encapsulating resin composition according to 3., wherein the black titanium oxide contains a compound represented by TiOx (wherein X is 1 or more and less than 2).
5. The encapsulating resin composition according to 3. or 4., wherein the black dye comprises one or more dyes selected from the group consisting of anthraquinone dyes, azine dyes, azo dyes, disazo dyes, and chromium complex dyes.
6. The encapsulating resin composition according to any one of 1. to 5., wherein the thermal conductivity calculated by the following procedure is 0.1 W/mK or more and 20 W/mK or less.
Procedure: A molded body (1.0×1.0 mm, thickness 1.0 mm) of the encapsulating resin composition is produced under conditions of a mold temperature of 175° C., an injection pressure of 6.9 MPa, and a curing time of 120 seconds, and a test piece is obtained by post-curing at 175° C. for 2 hours. The thermal diffusivity of the obtained test piece is measured by a laser flash method, and further, the specific gravity and specific heat are measured, and the thermal conductivity of the test piece in the thickness direction is calculated from the measured values.
7. In the L ^* a ^* b ^* color coordinates of the cured product of the encapsulating resin composition ,
The lightness L ^* value is 24 to 30;
the value of a ^* is −2.0 to −0.1;
7. The encapsulating resin composition according to any one of 1. to 6., wherein the b ^* value is −5.0 to −2.5.
8. The encapsulating resin composition according to any one of 1. to 7., further comprising an active ester resin.
9. The encapsulating resin composition according to any one of 1. to 8., which is in the form of particles, granules, tablets or sheets.
10. An electronic device comprising an electronic component and a sealing material that seals the electronic component,
10. An electronic device, wherein the encapsulant is a cured product of the encapsulating resin composition according to any one of 1. to 9.

The embodiments of the present invention will be described in detail based on examples and comparative examples. Note that the present invention is not limited to the examples.

<Preparation of Encapsulating Resin Composition>
The encapsulating resin compositions of the Examples, Comparative Examples, and Reference Examples were prepared as follows.
First, the components shown in Tables 1 and 2 were mixed using a mixer. The mixture was then roll-kneaded, cooled, and pulverized to obtain a powdered encapsulating resin composition.

Details of each component used are as follows:

(Epoxy resin)
Epoxy resin 1: Biphenylaralkyl type epoxy resin "NC3000" manufactured by Nippon Kayaku Co., Ltd. Epoxy resin 2: Biphenylaralkyl type epoxy resin "NC3000L" manufactured by Nippon Kayaku Co., Ltd. Epoxy resin 3: Orthocresol novolac type epoxy resin "EOCN-1020-55" manufactured by Chang Chun Plastics Co., Ltd. Epoxy resin 4: Trishydroxyphenylmethane type + biphenol type epoxy resin "YL6677" manufactured by Mitsubishi Chemical Corporation

(Hardening agent)
Curing agent 1: Biphenyl aralkyl type curing agent "MEH-7851SS" manufactured by Meiwa Kasei Co., Ltd. Curing agent 2: Ester type curing agent "EXB-8" manufactured by DIC Corporation Curing agent 3: Phenol-p-xylene glycol dimethyl ether polycondensate, manufactured by Air Water Co., Ltd. Curing agent 4: Phenol hydroxybenzaldehyde type curing agent "MEH-7500" manufactured by Meiwa Kasei Co., Ltd.

(Inorganic filler)
Inorganic filler 1: Silicon dioxide "SC-2500-SQ" manufactured by Adma, average particle size 0.5 μm
Inorganic filler 2: Silicon dioxide "TS-6021" manufactured by Micron, average particle size 10 μm
Inorganic filler 3: silicon dioxide "Rheolosil CP102" manufactured by Tokuyama Corporation, average particle size <1 μm
Inorganic filler 4: silicon dioxide, manufactured by Tokai Mineral Co., Ltd., average particle size 25 μm
Inorganic filler 5: silicon dioxide, "SC-2500-SQ" manufactured by Adma Co., Ltd., particle size 0.5 μm

(Coloring Agent)
Colorant 1: Black titanium oxide, manufactured by Ako Kasei Co., Ltd., average particle size 0.5 μm
Colorant 2: Carbon black, manufactured by Tokai Carbon Co., Ltd.

(Coupling Agent)
Coupling agent 1: Phenylaminopropyltrimethoxysilane "CF-4083" manufactured by Dow Corning Toray Co., Ltd. Coupling agent 2: γ-glycidoxypropylmethyldimethoxysilane "KE-6137" manufactured by Kyushu Sumitomo Bakelite Co., Ltd.

(Other adjusting ingredients)
Release agent 1: low molecular weight ethylene, manufactured by Sanyo Chemical Industries, Ltd., viscosity (140°C) 3500 to 5100 mPa·s
Release agent 2: Glycerol trimontanic acid ester "Licorb WE-4" manufactured by Clariant Japan Release agent 3: Oxidized polyethylene "Licowax PED191" manufactured by Clariant Japan Ion scavenger 1: Magnesium-aluminum compound, manufactured by Toagosei Ion scavenger 2: Magnesium-aluminum compound "DHT-4H" manufactured by Kyowa Chemical Industry Catalyst 1: 4-hydroxy-2-(triphenylphosphonium)phenolate, manufactured by Kei-I Chemical Industry Catalyst 2: 2,3-hydroxynaphthalene, manufactured by Air Water Inc. Flame retardant 1: Aluminum hydroxide "CL-303" manufactured by Sumitomo Chemical Industry Additive 1: Phenol-biphenylene resin and 4,4-sulfonyldiphenol Additive 1: Mixture of phenol-biphenylene resin and 4,4-sulfonyldiphenolate "MC11AC" manufactured by Kyushu Sumitomo Bakelite Co., Ltd. Additive 2: Mixture of phenol-biphenylene resin and 4,4-sulfonyldiphenolate "MC70E" manufactured by Kyushu Sumitomo Bakelite Co., Ltd. Additive 3: Silicone "Melted reaction product A described in paragraph 0068 of Japanese Patent No. 5157473" manufactured by Kyushu Sumitomo Bakelite Co., Ltd. Stress reducing agent 1: Carboxyl-terminated butadiene-acrylonitrile copolymer "CTBN1008SP" manufactured by PTI Japan Co., Ltd. Stress reducing agent 2: Epoxidized polybutadiene, manufactured by Nippon Soda Co., Ltd.

The following evaluations and measurements were carried out using the obtained encapsulating resin composition. The results are shown in Tables 1 and 2.

<Measurement of dielectric properties>
The obtained resin composition was molded at a mold temperature of 175°C, injection pressure of 10 MPa, and curing time of 2 minutes to produce a cured product of 100 x 3.8 x 0.8 mm. The obtained cured product was stored in a room at 23°C and 50% humidity for 24 hours after drying, and the dielectric constant (Dk) and dielectric loss tangent (Df) of the test piece at 5 GHz and 23°C were measured using "ASMS01Oc1" manufactured by AET Corporation in accordance with JIS-C-6481.

<Evaluation of color>
Each composition was cured by compression molding under conditions of a molding temperature of 175° C., a curing time of 100 seconds, and a molding pressure of 8 MPa to obtain a rectangular cured product.
The L ^* value, a ^* value and b ^* value of the surface of the cured product were measured using a Color Reader CR-13 (manufactured by Konica Minolta Sensing Co., Ltd.).

<Evaluation of thermal conductivity>
The obtained encapsulating resin composition was injected into a low pressure transfer molding machine ("KTS-30" manufactured by Kotaki Seiki Co., Ltd.) at a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a curing time of 120 seconds to obtain a molded body having a width of 10 mm, a thickness of 1 mm, and a length of 10 mm. The obtained molded body was then post-cured at 175°C for 2 hours to obtain a test piece. The thermal diffusivity of the obtained test piece was measured using a laser flash method (Xenon Flash Analyzer LFA447 manufactured by NETZSCH). In addition, the specific gravity of the test piece used for the thermal conductivity measurement was measured using an electronic specific gravity meter SD-200L manufactured by Alpha Mirage Co., Ltd., and further, the specific heat of the test piece used for the thermal conductivity and specific gravity measurement was measured using a differential scanning calorimeter DSC8230 manufactured by Rigaku Corporation. The thermal conductivity in the thickness direction of the test piece was calculated from the measured values of thermal diffusivity, specific gravity, and specific heat.

The composition of the encapsulating resin composition and the evaluation results are shown in Table 1.

1 Semiconductor element 2 Hardened die bond material 3 Die pad 4 Gold wire 5 Lead frame 6 Encapsulating material (hardened product of encapsulating resin composition)

Claims (10)

Epoxy resin,
A hardener;
An inorganic filler;
A colorant;
An encapsulating resin composition comprising:
the epoxy resin comprises one or more selected from a biphenyl aralkyl type epoxy resin, a novolac type epoxy resin, a trishydroxyphenylmethane type epoxy resin, and a biphenol type epoxy resin, and the content of the epoxy resin is 7.18 mass% or less based on the entire encapsulating resin composition;
The content of the inorganic filler is 60% by mass or more and 95% by mass or less with respect to the entire encapsulating resin composition,
the colorant contains at least one of black titanium oxide and a black dye, and the content of the colorant is 0.01% by mass or more and 3.0% by mass or less with respect to the entire encapsulating resin composition,
An encapsulating resin composition that satisfies the following conditions:
Condition: the encapsulating resin composition is used and cured at 175° C. for 2 minutes, and the cured product has a dielectric loss tangent at 5 GHz and 23° C. of less than 0.008. The encapsulating resin composition according to claim 1, wherein the colorant comprises carbon black. The encapsulating resin composition according to claim 1 or 2, wherein the black titanium oxide contains a compound represented by TiOx (wherein X is 1 or more and less than 2). The encapsulating resin composition according to any one of claims 1 to 3, wherein the black dye includes one or more selected from the group consisting of anthraquinone dyes, azine dyes, azo dyes, disazo dyes, and chromium complex dyes. The encapsulating resin composition according to claim 1 , wherein the thermal conductivity calculated by the following procedure is 0.1 W/mK or more and 20 W/mK or less.
Procedure: A molded body (1.0×1.0 mm, thickness 1.0 mm) of the encapsulating resin composition is produced under conditions of a mold temperature of 175° C., an injection pressure of 6.9 MPa, and a curing time of 120 seconds, and a test piece is obtained by post-curing at 175° C. for 2 hours. The thermal diffusivity of the obtained test piece is measured by a laser flash method, and further, the specific gravity and specific heat are measured, and the thermal conductivity of the test piece in the thickness direction is calculated from the measured values. In the L ^* a ^* b ^* color coordinates of the cured product of the encapsulating resin composition,
The lightness L ^* value is 24 to 30;
the value of a ^* is −2.0 to −0.1;
The encapsulating resin composition according to any one of claims 1 to 5, wherein the value of b ^* is -5.0 to -2.5. The encapsulating resin composition according to any one of claims 1 to 6, further comprising an active ester resin. The encapsulating resin composition according to claim 1 , wherein the curing agent comprises one or more selected from the group consisting of an ester type curing agent, a biphenyl aralkyl type curing agent , a phenol aralkyl resin, and an aromatic hydrocarbon formaldehyde resin-modified phenol resin. The encapsulating resin composition according to any one of claims 1 to 8, which is in the form of particles, granules, tablets or sheets. An electronic device comprising an electronic component and a sealant that seals the electronic component,
An electronic device, comprising an encapsulant comprising a cured product of the encapsulating resin composition according to claim 1 .

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