JP7589435B2 - Encapsulating resin composition, electronic component device, and method for manufacturing electronic component device - Google Patents

Description

The present invention relates to an encapsulating resin composition, an electronic component device, and a method for manufacturing an electronic component device.

For example, Patent Document 1 discloses an encapsulating epoxy resin molding material that contains a silicone compound and the application of the encapsulating epoxy resin molding material to a thin package.

JP 2006-241307 A

Wafer level package (WLP) is a technology for encapsulating a relatively large area with an encapsulating resin composition. As the area encapsulated with the encapsulating resin composition becomes larger, molding warpage tends to become more pronounced, and therefore, there is a demand for an encapsulating resin composition that can suppress the occurrence of molding warpage.
In addition, when a redistribution layer (RDL) is formed after encapsulation with the encapsulating resin composition, a material for forming the RDL (hereinafter also referred to as an "RDL-forming material") is applied onto the cured product of the encapsulating resin composition. Therefore, the cured product of the encapsulating resin composition is required to have excellent wettability with respect to the RDL-forming material (hereinafter also referred to as "RDL wettability").

The embodiments of the present disclosure have been made under the above circumstances.
An object of the present disclosure is to provide an encapsulating resin composition for wafer-level packaging that suppresses the occurrence of molding warpage in a cured product and has excellent RDL wettability, an electronic component device encapsulated using the same, and a method for manufacturing an electronic component device encapsulated using the same.

Specific means for solving the above problems include the following:

＜1＞
Epoxy resin,
A hardener;
Silicone having a glass transition temperature of 70° C. or less;
Contains
The sealing resin composition for wafer-level packages, wherein the content of the silicone is 30 parts by mass or less based on 100 parts by mass of the epoxy resin.
＜2＞
The encapsulating resin composition according to <1>, wherein the silicone has a viscosity at 25° C. of 1.0×10 ⁻² Pa·s to 1.0×10 ⁵ Pa·s.
＜3＞
The encapsulating resin composition according to <1> or <2>, wherein the curing agent contains an active ester compound.
＜4＞
A support member;
An element disposed on the support member;
A cured product of the encapsulating resin composition according to any one of <1> to <3>, which encapsulates the element; and
An electronic component device comprising:
＜5＞
The electronic component device according to <4>, further comprising a rewiring layer disposed on the cured product.
＜6＞
disposing a plurality of devices on a wafer;
A step of collectively encapsulating the plurality of elements with the encapsulating resin composition according to any one of <1> to <3>;
A step of singulating each encapsulated element;
A method for manufacturing an electronic component device comprising the steps of:

The present disclosure provides an encapsulating resin composition for wafer-level packages that suppresses molding warpage of the cured product and has excellent RDL wettability, an electronic component device encapsulated using the composition, and a method for manufacturing an electronic component device encapsulated using the composition.

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 ranges indicated using "to" include the numerical values before and after "to" as the minimum and maximum values, respectively.
In the numerical ranges described in the present disclosure in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.
In the present disclosure, each component may contain multiple types of the corresponding substance. When multiple substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified.
In the present disclosure, the particles corresponding to each component may include multiple types. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.

The following describes in detail the form for implementing the present disclosure. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the components (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values and their ranges, and do not limit the present disclosure.

<Sealing resin composition>
The encapsulating resin composition according to one embodiment of the present disclosure is an encapsulating resin composition for wafer-level packaging, and is made of an epoxy resin, a curing agent, and a silicone having a glass transition temperature of 70° C. or less (hereinafter referred to as “ The content of the specific silicone is 30 parts by mass or less per 100 parts by mass of the epoxy resin.

As described above, wafer level packaging is a technique for sealing a relatively large area with an encapsulating resin composition, and the larger the area sealed with the encapsulating resin composition, the more pronounced the warpage tends to be.
On the other hand, when silicone is added for the purpose of suppressing molding warpage, the wettability of the cured product of the encapsulating resin composition to the RDL-forming material (i.e., RDL wettability) may be reduced. In particular, when a silicone with a glass transition temperature of 70° C. or less (i.e., a specific silicone) is used as the silicone, the effect of suppressing molding warpage is high, but the RDL wettability is likely to be low. Although the reason is unclear, it is speculated that the specific silicone seeps out onto the surface during the curing process of the encapsulating resin composition, and the specific silicone is exposed on the surface of the cured product, making the RDL-forming material more likely to be repelled. And, when an RDL-forming material for forming a rewiring layer (RDL) is applied onto the cured product of the encapsulating resin composition with low RDL wettability, the RDL-forming material may be repelled, causing a defective appearance.
In contrast, the encapsulating resin composition of the present embodiment contains the specific silicone, and the content of the specific silicone is 30 parts by mass or less per 100 parts by mass of the epoxy resin. Therefore, even if the encapsulating resin composition contains the specific silicone, it is unlikely for the specific silicone to seep out to the surface during the curing process, and it is presumed that the cured product can achieve both suppression of molding warpage and excellent RDL wettability.

The glass transition temperature of the specific silicone herein is a temperature determined from a DSC curve obtained by differential scanning calorimetry (DSC), and is the "extrapolated glass transition onset temperature" described in "Method for determining glass transition temperature" of JIS K7121:1987 "Method for measuring transition temperature of plastics."
Specifically, for example, a DSC Q200 (TA Instruments) is used as a measuring device, and the measurement is performed in a temperature range from 25° C. to 300° C. at a temperature increase rate of 10° C./min.
Hereinafter, each component contained in the encapsulating resin composition according to this embodiment will be described.

(Epoxy resin)
The type of epoxy resin is not particularly limited as long as it has an epoxy group in the molecule.

Specific examples of epoxy resins include novolac-type epoxy resins (phenol novolac-type epoxy resins, orthocresol novolac-type epoxy resins, etc.) which are obtained by epoxidizing novolac 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, 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 acid catalyst; triphenylmethane-type phenolic resins which are obtained by condensing or co-condensing the above-mentioned phenolic compound with an aromatic aldehyde compound such as benzaldehyde, salicylaldehyde, etc., under an acid catalyst; diphenylmethane type epoxy resins; 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 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, and polypropylene glycol; glycidyl ester type epoxy resins which are glycidyl esters of polyvalent carboxylic acid compounds such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid. epoxy resins; glycidylamine-type epoxy resins in which active hydrogen attached to nitrogen atoms of aniline, diaminodiphenylmethane, isocyanuric acid, etc. is replaced with a glycidyl group; dicyclopentadiene-type epoxy resins in which a co-condensed 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 phenol resins; metaxylylene-modified epoxy resins which are glycidyl ethers of metaxylylene-modified phenol resins; terpene-modified phenols; Terpene-modified epoxy resins are glycidyl ethers of phenol resins; dicyclopentadiene-modified epoxy resins are glycidyl ethers of dicyclopentadiene-modified phenol resins; cyclopentadiene-modified epoxy resins are glycidyl ethers of cyclopentadiene-modified phenol resins; polycyclic aromatic ring-modified epoxy resins are glycidyl ethers of polycyclic aromatic ring-modified phenol resins; naphthalene-type epoxy resins are glycidyl ethers of naphthalene ring-containing phenol 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 phenol resins such as phenol aralkyl resins and naphthol aralkyl resins; and the like. Furthermore, epoxy-oxidized acrylic resins and the like can also be mentioned as epoxy resins. These 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, but from the viewpoint of a 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 a value measured by a method in accordance with JIS K 7236:2009.

When the epoxy resin is a solid, the softening point or melting point of the epoxy resin is not particularly limited, but is preferably 40° C. to 180° C. from the viewpoints of moldability and reflow resistance, and more preferably 50° C. to 130° C. from the viewpoint of handleability during preparation of the encapsulating resin composition.
The melting point or softening point of the epoxy resin is a value measured by differential scanning calorimetry (DSC) or a method in accordance with JIS K 7234:1986 (ring and ball method).

The mass ratio of the epoxy resin to the total amount of the encapsulating resin composition is preferably 0.5% by mass to 50% by mass, and more preferably 2% by mass to 30% by mass, from the viewpoints of strength, fluidity, heat resistance, moldability, etc.

(Hardening agent)
The encapsulating resin composition according to the present embodiment contains a curing agent. The type of the curing agent is not particularly limited.
The curing agent preferably contains an active ester compound. Here, the 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 the ability to cure an epoxy resin.

The amount of transmission loss that occurs when radio waves transmitted for communication are converted into heat in a dielectric is expressed as the product of frequency, the square root of the relative dielectric constant, and the dielectric loss tangent. In other words, since the transmission signal is more likely to turn into heat in proportion to the frequency, the lower the dielectric properties required of the materials used in communication components in order to suppress transmission loss, the higher the frequency band. In the field of information and communication, radio waves are becoming increasingly high frequency as the number of channels and the amount of information transmitted increase. Currently, the practical application of the fifth generation mobile communication system is progressing worldwide, and several frequency bands in the range of approximately 30 GHz to 70 GHz are being considered as candidates for the frequency bands to be used. Since communication in such high frequency bands will become the mainstream in wireless communication in the future, materials used in communication components are being required to have even lower dielectric loss tangents.

Conventionally, phenol curing agents, amine curing agents, etc. are generally used as curing agents for epoxy resins, but secondary hydroxyl groups are generated in the reaction between an epoxy resin and a phenol curing agent or an amine curing agent. In contrast, ester groups are generated instead of secondary hydroxyl groups in the reaction between an epoxy resin and an active ester compound. Since ester groups have a lower polarity than secondary hydroxyl groups, an encapsulating resin composition containing an active ester compound as a curing agent can reduce the dielectric tangent of the cured product compared to an encapsulating resin composition containing only a curing agent that generates secondary hydroxyl groups as a curing agent.
In addition, while polar groups in a cured product increase the water absorption of the cured product, the polar group concentration of the cured product can be reduced by using an active ester compound as a curing agent, and the water absorption of the cured product can be reduced. Furthermore, by reducing the water absorption of the cured product, that is, by reducing the content of _H2O , which is a polar molecule, the dielectric tangent of the cured product can be further reduced.

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 that use 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 that use 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).

As the active ester compound, commercially available products may be used. Commercially available active ester compounds 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, but from the viewpoint of the balance of various properties such as moldability, reflow resistance, and electrical reliability, it is preferably 150 g/eq to 400 g/eq, more preferably 170 g/eq to 300 g/eq, and even more preferably 200 g/eq to 250 g/eq.
The ester equivalent of the active ester compound is a value measured by a method in accordance with 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 0.9 or more, more preferably 0.95 or more, and even more preferably 0.97 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 1.1 or less, more preferably 1.05 or less, and even more preferably 1.03 or less.

The curing agent may contain other curing agents other than the active ester compound. In this case, the type of other curing agent is not particularly limited and can be selected according to the desired properties of the encapsulating resin composition. Examples of other curing agents include phenol curing agents, amine curing agents, acid anhydride curing agents, polymercaptan curing agents, polyaminoamide curing agents, isocyanate curing agents, blocked isocyanate curing agents, etc.

Specific examples of phenolic hardeners 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, phenylphenol, and aminophenol, and naphthol compounds such as α-naphthol, β-naphthol, and dihydroxynaphthalene, with aldehyde compounds such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and salicylaldehyde, under an acid catalyst; and polyphenolic compounds such as dimethoxyparaxylene, bis(methoxymethyl)biphenyl, and the like. Examples of the phenol curing agent include aralkyl-type phenolic resins such as phenol aralkyl resins and naphthol aralkyl resins synthesized from phenol and the like; paraxylylene-modified phenolic resins and metaxylylene-modified phenolic resins; melamine-modified phenolic resins; terpene-modified phenolic resins; dicyclopentadiene-type phenolic resins and dicyclopentadiene-type naphthol resins synthesized by copolymerization of the above-mentioned phenolic compounds 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 the other curing agent (hydroxyl group equivalent in the case of a phenolic curing agent) is not particularly limited, and 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 curing agents (hydroxyl group equivalent in the case of a phenolic curing agent) is a value measured by a method in accordance with JIS K 0070:1992.

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

The melting point or softening point of the hardener shall be a value measured in the same manner as the melting point or softening point of the epoxy resin.

The equivalent ratio of the epoxy resin to all curing agents (active ester 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.

The mass ratio of the active ester compound to the total amount of the active ester compound and other curing agents is preferably 80 mass% or more, more preferably 85 mass% or more, and even more preferably 90 mass% or more, from the viewpoint of keeping the dielectric tangent of the cured product low.

The total mass ratio of the epoxy resin and the active ester compound to the total amount of the epoxy resin, the active ester compound, and other curing agents is preferably 80% by mass or more, more preferably 85% 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.

(Specific silicone)
The specific silicone is not particularly limited as long as it is a silicone having a glass transition temperature of not more than 70° C. The specific silicone may be used alone or in combination of two or more kinds.
The specific silicone has a glass transition temperature of 70° C. or less, and from the viewpoint of suppressing the occurrence of warping during molding of the cured product, it is more preferably 50° C. or less, and further preferably has a Tg of 30° C. or less.

Examples of the specific silicones include polyether-modified silicones having a polyether group introduced therein, epoxy-modified silicones having an epoxy group introduced therein, epoxy-polyether-modified silicones having a polyether group and an epoxy group introduced therein, acrylic-modified silicones having an acryloyl group introduced therein, methacrylic-modified silicones having a methacryloyl group introduced therein, and polycaprolactone-modified silicones having a polycaprolactone group introduced therein.
Of these, the specific silicone is preferably polyether-modified silicone, epoxy-modified silicone, epoxy-polyether-modified silicone, or acrylic-modified silicone, and from the viewpoint of RDL wettability, more preferably epoxy-polyether-modified silicone, which has low polarity.
The specific silicone may be a side-chain-modified silicone or a terminal-modified silicone, and among these, the specific silicone is preferably a side-chain-modified silicone.

As mentioned above, an example of the specific silicone is epoxy-polyether modified silicone. The epoxy-polyether modified silicone is not particularly limited as long as it is a compound in which a polyether group and an epoxy group are introduced into silicone, which is a polymeric compound having a main skeleton formed by siloxane bonds.
The epoxy polyether modified silicone may be a side chain modified epoxy polyether modified silicone, a terminal modified epoxy polyether modified silicone, or a side chain and terminal modified epoxy polyether modified silicone. The main skeleton of the epoxy polyether modified silicone is preferably polydimethylsiloxane. The polyether group is preferably a polyether group in which one or both of ethylene oxide and propylene oxide are polymerized.
The epoxy-polyether modified silicone is preferably a side-chain modified epoxy-polyether modified silicone in which a polyether group (preferably a polyether group in which one or both of ethylene oxide and propylene oxide are polymerized) and an epoxy group are present in the side chain of a silicone (preferably polydimethylsiloxane). An example of a commercially available product of the epoxy-polyether modified silicone is "SIM768E" manufactured by Momentive Performance Materials.

Another example of the specific silicone is polycaprolactone-modified silicone, as described above. The polycaprolactone-modified silicone is not particularly limited as long as it is a compound obtained by reacting caprolactone with silicone, which is a polymeric compound having a main skeleton formed by siloxane bonds.
The polycaprolactone-modified silicone may be a side-chain-modified polycaprolactone-modified silicone, a one-terminal-modified polycaprolactone-modified silicone, or a both-terminal-modified polycaprolactone-modified silicone, with both-terminal-modified polycaprolactone-modified silicone being preferred. The main skeleton of the polycaprolactone-modified silicone is preferably polydimethylsiloxane. An example of a commercially available product of polycaprolactone-modified silicone, which is a both-terminal-modified type of polydimethylsiloxane, is "DBL-C32" manufactured by Gelest.

The viscosity of the specific silicone at 25° C. is not particularly limited. From the viewpoint of suppressing the occurrence of molding warpage of the cured product of the encapsulating resin composition, the viscosity (25° C.) of the specific silicone is preferably 1.0×10 ⁻² Pa·s to 1.0×10 ⁵ Pa·s, more preferably 1.0×10 ⁻² Pa·s to 8.0×10 ⁴ Pa·s, even more preferably 1.0 Pa·s to 8.0×10 ⁴ Pa·s, particularly preferably 1.0 Pa·s to 4.0×10 Pa·s, extremely preferably 1.0 Pa·s to 1.0×10 Pa·s, and most preferably 1.0 Pa·s to 4.0 Pa·s.
Furthermore, the viscosity at 100°C of the specific silicone having a glass transition temperature of 40°C or higher and 70°C or lower is preferably 1.0 x 10 ^-2 Pa·s to 1.0 x 10 ² Pa·s, more preferably 1.0 Pa·s to 1.0 x 10 2 Pa·s, and even more preferably 1.0 Pa·s to 5.0 x ¹⁰ Pa·s, from the viewpoint of suppressing the occurrence of molding warpage of the cured product of the encapsulating resin composition.
The viscosity of the specific silicone at 25° C. and at 100° C. is a value measured by a method conforming to JIS Z 8803: 2011. Specifically, for example, a KINEXUS (Spectris Corporation, product name "KT4") is used as a measuring device, and the measurement is performed under conditions of a temperature of 25° C. or 100° C., a frequency of 1 Hz, and a strain of 1%.

The content of the specific silicone is 30 parts by mass or less relative to 100 parts by mass of the epoxy resin. From the viewpoint of achieving both suppression of molding warpage of the cured product and excellent RDL wettability, the content is preferably 8 parts by mass to 30 parts by mass, more preferably 8 parts by mass to 20 parts by mass, and even more preferably 10 parts by mass to 15 parts by mass.
In particular, when a silicone having a glass transition temperature of 40° C. or more and 70° C. or less is used as the specific silicone, the content of the specific silicone is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 8 parts by mass to 20 parts by mass, relative to 100 parts by mass of the epoxy resin, also from the viewpoint of obtaining flowability of the encapsulating resin composition.

(Cure Accelerator)
The encapsulating resin composition may contain a curing accelerator as necessary. The type of the curing accelerator is not particularly limited and can be selected depending on the type of epoxy resin or curing agent, the desired properties of the encapsulating resin composition, and the like.

Examples of hardening accelerators include diazabicycloalkenes such as 1,5-diazabicyclo[4.3.0]nonene-5 (DBN) and 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), cyclic amidine compounds such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole; derivatives of the cyclic amidine compounds; phenol novolac salts of the cyclic amidine compounds or their derivatives; and mixtures of these compounds with maleic anhydride. compounds having intramolecular polarization obtained by adding a compound having a π bond, such as quinone compounds, such as diazophenylmethane, quinone compounds, such as phenyl-1,4-benzoquinone, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, and phenyl-1,4-benzoquinone; tetraphenylborate salt of DBU, tetraphenylborate salt of DBN, Cyclic amidinium compounds such as tetraphenylborate salt of 2-ethyl-4-methylimidazole and tetraphenylborate salt of N-methylmorpholine; tertiary amine compounds such as pyridine, triethylamine, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; derivatives of the above tertiary amine compounds; ammonium salt compounds such as tetra-n-butylammonium acetate, tetra-n-butylammonium phosphate, tetraethylammonium acetate, tetra-n-hexylammonium benzoate, and tetrapropylammonium hydroxide; triphenylphosphine, diphenyl(p-tolyl)phosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, tris(alkyl.alkoxyphenyl)phosphine, tris(dialkylphenyl)phosphine, tris(trialkylphenyl)phosphine, and tris(tetraalkylphenyl). Tertiary phosphines such as phosphine, tris(dialkoxyphenyl)phosphine, tris(trialkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, trialkylphosphine, dialkylarylphosphine, and alkyldiarylphosphine; phosphine compounds such as complexes of the above-mentioned tertiary phosphines with organic borons; compounds having intramolecular polarization obtained by adding a compound having a π bond to the above-mentioned tertiary phosphine or the above-mentioned phosphine compound, such as maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, and phenyl-1,4-benzoquinone, and diazophenylmethane; the above-mentioned tertiary phosphine or the above-mentioned phosphine compound and 4-bromophenol, 3-bromophenol, 2-bromophenol, 4-chlorophenol, Compounds having intramolecular polarization obtained by reacting a halogenated phenol compound such as 3-chlorophenol, 2-chlorophenol, 4-iodophenol, 3-iodophenol, 2-iodophenol, 4-bromo-2-methylphenol, 4-bromo-3-methylphenol, 4-bromo-2,6-dimethylphenol, 4-bromo-3,5-dimethylphenol, 4-bromo-2,6-di-tert-butylphenol, 4-chloro-1-naphthol, 1-bromo-2-naphthol, 6-bromo-2-naphthol, or 4-bromo-4'-hydroxybiphenyl with the resulting compound and then carrying out a dehydrohalogenation process; tetra-substituted phosphonium compounds such as tetraphenylphosphonium compounds, tetra-substituted phosphonium compounds and tetra-substituted borates that do not have a phenyl group bonded to a boron atom, such as tetra-p-tolylborate compounds; salts of tetraphenylphosphonium compounds and phenol compounds; salts of tetraalkylphosphonium compounds and partial hydrolysates of aromatic carboxylic acid anhydrides.

When the encapsulating resin composition contains a curing accelerator, the amount is preferably 0.1 to 30 parts by mass, and more preferably 1 to 15 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 curing accelerator is 0.1 parts by mass or more per 100 parts by mass of the resin component, the composition tends to cure well in a short time. When the amount of the curing accelerator is 30 parts by mass or less per 100 parts by mass of the resin component, the curing speed is not too fast and a good molded product tends to be obtained.

(Inorganic filler)
The encapsulating resin composition may contain an inorganic filler as necessary. The type of inorganic filler is not particularly limited. Specific examples of inorganic materials include fused silica, crystalline silica, glass, alumina, calcium carbonate, zirconium silicate, calcium silicate, silicon nitride, aluminum nitride, boron nitride, beryllia, zirconia, zircon, fosterite, steatite, spinel, mullite, titania, 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 obtained by sphering 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 further suppressed. When the average particle size is 100 μm or less, the filling property tends to be further improved. The average particle size of the inorganic filler is determined as the volume average particle size (D50) using a laser scattering diffraction particle size distribution measuring device.

From the viewpoint of controlling the elastic modulus of the cured product of the encapsulating resin composition, the content of the inorganic filler contained in the encapsulating resin composition is preferably 60% by volume to 82% by volume of the entire encapsulating resin composition, more preferably 62% by volume to 80% by volume, even more preferably 65% by volume to 80% by volume, and even more preferably 65% by volume to 78% by volume.

The volume ratio of the inorganic filler in the encapsulating resin composition can be determined by the following method.
A thin sample of the cured product of the encapsulating resin composition is photographed with a scanning electron microscope (SEM). An arbitrary area S is specified in the SEM image, and the total area A of the inorganic filler contained in the area S is calculated. The total area A of the inorganic filler is divided by the area S to convert it into a percentage (%), and this value is regarded as the volume ratio of the inorganic filler in the encapsulating resin composition.
The area S is set to be sufficiently large relative to the size of the inorganic filler, for example, a size that contains 100 or more inorganic fillers. The area S may be the total area of a plurality of cut surfaces.
The inorganic filler may have a biased presence ratio in the direction of gravity when the encapsulating resin composition is cured. In such a case, when imaging with an SEM, an image of the entire cured product in the direction of gravity is taken, and the area S including the entire cured product in the direction of gravity is specified.

[Various additives]
In addition to the above-mentioned components, the encapsulating resin composition may contain various additives such as coupling agents, ion exchangers, release agents, flame retardants, colorants, etc., as exemplified below. 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, vinylsilane, and disilazane, 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 an electronic component device including an element to be encapsulated. The ion exchanger is not particularly limited, and a conventionally known ion exchanger can be used. Specific examples include hydrotalcite compounds and hydrous oxides of at least one element selected from the group consisting of magnesium, aluminum, titanium, zirconium, and bismuth. The ion exchanger may be used alone or in combination of two or more types. Among them, hydrotalcite represented by the following general formula (A) is preferred.

Mg _(1-X) Al _X (OH) ₂ (CO ₃ ) _X/2・mH ₂ O ... (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 a sufficient amount to capture ions such as halogen ions. For example, it 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 (total amount of epoxy resin and 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 retardant)
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, such as carbon black, an organic dye, an organic pigment, titanium oxide, red lead, or red iron oxide.
The content of the colorant can be appropriately selected depending on the purpose, etc. 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 uniformly 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.

<Electronic component device>
The electronic component device according to an embodiment of the present disclosure is manufactured by wafer level package (WLP). That is, the electronic component device of the present embodiment is manufactured by mounting a plurality of elements (active elements such as semiconductor chips, transistors, diodes, and thyristors, and passive elements such as capacitors, resistors, and coils) on a wafer, encapsulating the plurality of elements with an encapsulating resin composition, and then dividing the encapsulated elements into individual pieces. WLP may be FOWLP (Fan Out Wafer Level Package) or FIWLP (Fan In Wafer Level Package, also called WLCSP (Wafer level Chip Size Package).).
The electronic component device of the present embodiment includes a support member, an element disposed on the support member, and a cured product of the encapsulating resin composition of the present disclosure encapsulating the element. The electronic component device of the present embodiment may further include a redistribution layer disposed on the cured product.

<Method of Manufacturing Electronic Component Device>
The method for manufacturing an electronic component device according to an embodiment of the present disclosure includes a step of arranging a plurality of elements on a wafer, a step of collectively encapsulating the plurality of elements with the encapsulating resin composition of the present disclosure, and a step of singulating each of the encapsulated elements. That is, the method for manufacturing an electronic component device according to the present embodiment is a manufacturing method including wafer-level packaging. The method for manufacturing an electronic component device according to the present embodiment may further include a step of forming a rewiring layer on the cured product of the encapsulating resin composition formed by the encapsulating step. In this case, the singulating step is performed, for example, after the step of forming the rewiring layer.

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 types of wafers and elements used in the manufacture of electronic component devices are not particularly limited, and wafers and elements commonly used in the manufacture of electronic component devices can be used.

The wafer material used in WLP is usually a crystal of a semiconductor material, typically a single crystal of silicon. The size of the wafer is not particularly limited, but may be, for example, 6 to 12 inches in diameter, and preferably 10 to 12 inches in diameter.

Methods for encapsulating elements using the encapsulating resin composition of the present disclosure include low-pressure transfer molding, injection molding, compression molding, and the like. Of these, low-pressure transfer molding is the most common.

As a method for forming the rewiring layer, for example, a method in which an RDL forming material is applied onto an encapsulating resin composition and then spin-coated to form the rewiring layer can be mentioned.
Examples of materials for forming the RDL include HD-7110 (manufactured by Hitachi Chemical), HD-8820 (manufactured by Hitachi Chemical), and BL-301 (manufactured by Asahi Chemical).

The above embodiment will be explained in detail below using examples, but the scope of the above embodiment is not limited to these examples.

<Preparation of Encapsulating Resin Composition>
The encapsulating resin compositions of Examples and Comparative Examples were prepared by mixing the components shown below in the blending ratios (parts by mass) shown in Table 1. The encapsulating resin compositions were solid at room temperature and normal pressure.

Epoxy resin 1: biphenyl type epoxy resin, epoxy equivalent 186 g/eq (Mitsubishi Chemical Corporation, product name "YX-4000")
Epoxy resin 2: triphenylmethane type epoxy resin, epoxy equivalent 167 g/eq (Mitsubishi Chemical Corporation, product name "1032H60")

Hardener 1: Active ester compound (DIC Corporation, product name "EXB-8")
Hardener 2: Phenol hardener, phenol aralkyl resin, hydroxyl equivalent 175 g/eq (Meiwa Kasei Co., Ltd., product name "MEH7800SS")

Release agent 1: Montan acid ester wax (Clariant Japan Co., Ltd., product name "HW-E")
Coupling agent 1: 3-methacryloxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., product name "KBM-503")
Coupling agent 3: N-phenyl-3-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., product name "KBM-573")
Curing accelerator 1: Triphenylphosphine/1,4-benzoquinone adduct Colorant 1: Carbon black (Mitsubishi Chemical Corporation, product name "MA600")
Inorganic filler 1: fused silica (average particle size 4.5 μm)
Inorganic filler 2: fused silica (average particle size 0.6 μm)

Specific silicone 1: end-modified polyether-modified silicone, Tg: 60° C., viscosity (25° C.): 8.0×10 ⁴ Pa·s, viscosity (100° C.): 30 Pa·s
Specific silicone 2: Side chain modified epoxy/polyether modified silicone, Tg: 25° C. or less, Viscosity (25° C.): 1.5 Pa·s
Specific silicone 3: Side chain modified epoxy-polyether modified silicone, Tg: 25°C or less, Viscosity (25°C): 4.5 Pa·s (Shin-Etsu Chemical Co., Ltd., Product name "KF-1002")
Specific silicone 4: Side chain modified epoxy-polyether modified silicone, Tg 25°C or less, viscosity (25°C): 0.35 Pa·s (Shin-Etsu Chemical Co., Ltd., product name "X-22-4741")
Specific silicone 5: terminally modified acrylic modified silicone, Tg 25°C or less, viscosity (25°C): 0.3 Pa·s (Siltech, product name "Silmer ACR Di-50")

<Performance Evaluation of Encapsulating Resin Composition>
(Dielectric constant and dielectric loss tangent)
The encapsulating resin composition was charged into a vacuum hand press and molded under the conditions of a mold temperature of 175°C, molding pressure of 6.9 MPa, and curing time of 600 seconds, and post-curing was performed at 180°C for 6 hours to obtain a plate-shaped cured product (length 12.5 mm, width 25 mm, thickness 0.2 mm). The plate-shaped cured product was used as a test piece and the relative dielectric constant and dielectric loss tangent were measured at a temperature of 25±3°C and about 60 GHz using a dielectric constant measuring device (Agilent Technologies, product name "Network Analyzer N5227A"). The results are shown in Table 1.

(Molding warpage)
A mold and a release film were prepared for molding, by compression molding, a laminate in which a 200 μm-thick cured resin product was laminated on a 12-inch diameter silicon wafer. Using this mold, release film, 12-inch diameter silicon wafer, and encapsulating resin composition, a laminate in which a cured product of the encapsulating resin composition was laminated on a silicon wafer was molded under conditions of a mold temperature of 175° C., a molding pressure of 7 MPa, and a curing time of 300 seconds.
The laminate was measured for mold warpage using a shadow moire measuring device (TherMoireAXP, manufactured by Akrometrix). Warpage of 2.0 mm or less was within the acceptable range (◯).

(RDL wettability)
HD-7110 (manufactured by Hitachi Chemical) was used as the RDL forming material.
The surface of the cured product of the encapsulating resin composition molded into a disk shape with a diameter of 10 cm and a thickness of 3 mm was polished with #3000 and dried at 110° C. for 1 hour. The RDL-forming material was applied onto the cured product of the encapsulating resin composition by spin coating, and dried at 200° C. for 1 hour, and then the RDL wettability was evaluated according to the following criteria. The results are shown in Table 1.

-Evaluation criteria-
A (◯): 5 or less defects B (△): 6 to 20 defects C (×): 21 or more defects

Compared to the encapsulating resin composition of the comparative example, the encapsulating resin composition of the example achieved both suppression of molding warpage of the cured product and excellent RDL wettability.

Claims (8)

Epoxy resin,
A hardener;
Silicone with a glass transition temperature of 40°C to 70°C;
An encapsulating resin composition comprising:
The silicone includes an epoxy-polyether modified silicone,
the content of the silicone is 8 parts by mass to 30 parts by mass relative to 100 parts by mass of the epoxy resin,
The encapsulating resin composition is solid at 25° C. and atmospheric pressure.
An encapsulating resin composition for wafer-level packaging. 2. The encapsulating resin composition according to claim 1, wherein the silicone has a viscosity at 25° C. of 1.0×10 ⁻² Pa·s to 1.0×10 ⁵ Pa·s. 2. The encapsulating resin composition according to claim 1, wherein the silicone has a viscosity at 25° C. of 1.0 Pa·s to 1.0×10 ⁵ Pa·s. The encapsulating resin composition according to any one of claims 1 to 3, wherein the curing agent comprises an active ester compound. A support member;
An element disposed on the support member;
A cured product of the encapsulating resin composition according to any one of claims 1 to 4 which encapsulates the element; and
An electronic component device comprising: The electronic component device according to claim 5 , further comprising a rewiring layer disposed on the cured product. disposing a plurality of devices on a wafer;
a step of collectively encapsulating the plurality of elements with the encapsulating resin composition according to any one of claims 1 to 4 ;
A step of singulating each encapsulated element;
A method for manufacturing an electronic component device comprising the steps of: The method further includes a step of forming a rewiring layer on the cured product of the encapsulating resin composition formed in the encapsulating step,
The method for manufacturing an electronic component device according to claim 7 , wherein the step of dividing the semiconductor device into individual pieces is carried out after the step of forming the rewiring layer.