JP2020097753A - Sealing epoxy resin composition, and semiconductor device and method for manufacturing the same - Google Patents

Abstract

To provide a sealing epoxy resin composition capable of forming a cured product which has a large thermal shrinkage from a molding temperature to a room temperature, and has high elasticity modulus in a reflow process.SOLUTION: There is provided a sealing epoxy resin composition which contains (A) an epoxy resin, (B) a phenol novolak resin that has an allyl group, and (C) an inorganic filler.SELECTED DRAWING: None

Description

The present disclosure relates to a sealing epoxy resin composition, a semiconductor device, and a method for manufacturing the same.

In recent years, the demand for high-density mounting due to the miniaturization and thinning of electronic devices has rapidly increased. For this reason, as the semiconductor package, a surface mount type suitable for high-density mounting has become mainstream instead of the conventional pin insertion type. This surface mount type semiconductor package is manufactured by directly soldering the leads to a printed circuit board or the like. As a heating method, there are infrared reflow, vapor phase reflow, solder dip, etc., and the semiconductor element is mounted on a printed circuit board or the like by heating the entire package by any heating method.

After surface mounting, the space between the semiconductor element and the substrate is filled with an underfill material in order to protect the surface of the semiconductor element and ensure the connection reliability between the semiconductor element and the substrate. ..

Since the shape of the single-sided resin sealed package filled with the underfill material is single-sided sealed, it is possible to reduce the difference in the coefficient of linear expansion and the difference in the elastic modulus between the package components such as the sealing resin and the substrate. Warpage occurs due to the thermal stress generated as a result. As a result, problems such as transportability problems and deterioration of mounting reliability during the reflow process occur.

In order to suppress such a phenomenon, it is desired to reduce thermal stress generated due to a difference in coefficient of linear expansion between package components such as a sealing resin and a substrate and a difference in elastic modulus. For example, Patent Document 1 proposes to reduce the difference in thermal response behavior among the semiconductor element, the cured product of the thermosetting resin composition, and the adherend in order to improve reliability.

JP, 2014-210880, A

In recent semiconductor packages, the number of packages having a thin sealing resin layer is increasing. To reduce the size and thickness of a semiconductor device, it is sufficient to reduce the thickness of the semiconductor element, but as the thickness of the semiconductor element progresses, the influence of thermal response behavior (warping, expansion, etc.) on the semiconductor element increases. .. This is because the coefficient of thermal expansion of the substrate or the like is generally larger than the value of the semiconductor element. In particular, stress due to the difference in thermal response behavior between the semiconductor element and the substrate tends to concentrate on the connecting member such as a solder bump that connects the semiconductor element and the substrate, and in some cases, the joint may break.

In a package form in which a sealing resin layer is formed on the upper side of a semiconductor element, an upward warp (hereinafter referred to as “cry warp”) occurs at room temperature and a downward warp at a reflow temperature (hereinafter referred to as “smile warp”). ")) phenomenon occurs. In order to suppress such a phenomenon, by increasing the elastic modulus at the reflow temperature while maintaining a large thermal contraction rate (coefficient of linear expansion: CTE1) of the sealing resin from the molding temperature to the room temperature, the cry warp caused by the substrate Can be suppressed.

The present invention provides an epoxy resin composition for encapsulation which has a large thermal shrinkage (linear expansion coefficient: CTE1) from the molding temperature to room temperature and can form a cured product having a high elastic modulus during a reflow process. The purpose is to do. Another object of the present invention is to provide a semiconductor device in which warpage is suppressed by using the encapsulating epoxy resin composition, and a method for manufacturing such a semiconductor device.

The present invention, in one aspect, provides an epoxy resin composition for encapsulation, which comprises (A) an epoxy resin, (B) an allyl group-containing phenol novolac resin, and (C) an inorganic filler. The encapsulating epoxy resin composition can form a cured product having a large thermal shrinkage (linear expansion coefficient: CTE1) from the molding temperature to room temperature and a high elastic modulus during the reflow process. This makes it possible to reduce the difference in thermal response behavior between the semiconductor element and the substrate when used for manufacturing a semiconductor device. Therefore, when a semiconductor device is manufactured by integrally molding a semiconductor element, a metal such as a bump, and a substrate, it is possible to sufficiently suppress the occurrence of warpage. As a result, the reliability of the package during the reflow process can be improved.

The (B) phenol novolac resin having an allyl group preferably has a structure represented by the following general formula (i).

In the general formula (i), n represents an integer of 0 or more.

The allyl group of the phenol novolac resin (B) having an allyl group is preferably in the ortho position. The content of the (B) phenol novolac resin having an allyl group is preferably 3 to 15% by mass. The inorganic filler (C) preferably contains silica.

The present invention, in another aspect, provides a semiconductor device comprising an element sealed with a cured product of the above-mentioned epoxy resin composition for sealing. The cured product of the epoxy resin composition for encapsulation in this semiconductor device has a large coefficient of thermal shrinkage (linear expansion coefficient: CTE1) from the molding temperature to room temperature, and has a high elastic modulus during the reflow process. Therefore, the occurrence of warpage is sufficiently reduced. Examples of the element include a semiconductor element.

The present invention, in yet another aspect, provides a method for manufacturing a semiconductor device, which includes a step of sealing using the above-mentioned sealing epoxy resin composition. A cured product of the epoxy resin composition for encapsulation has a large coefficient of thermal shrinkage (coefficient of linear expansion: CTE1) from the molding temperature to room temperature, and has a high elastic modulus during the reflow process. Therefore, it is possible to manufacture a semiconductor device in which warpage is sufficiently reduced.

ADVANTAGE OF THE INVENTION According to this invention, the epoxy resin composition for sealing which can form the hardened|cured material which has a large thermal contraction rate (linear expansion coefficient: CTE1) from molding temperature to normal temperature, and has a high elastic modulus at the time of a reflow process. Will be provided. Further, by using the encapsulating epoxy resin composition, a semiconductor device in which the occurrence of warpage is suppressed, and a method for manufacturing such a semiconductor device are provided.

Hereinafter, embodiments of the present invention will be described. However, the following embodiments are examples for explaining the present invention and are not intended to limit the present invention to the following contents.

In the present specification, the numerical range indicated by using "to" indicates the range including the numerical values before and after "to" as the minimum value and the maximum value, respectively. Furthermore, when referring to the amounts of the respective components in the composition in the present specification, when there are a plurality of substances corresponding to the respective components in the composition, the plurality of the substances present in the composition are used unless otherwise specified. Means the total amount of a substance.

<Epoxy resin composition for sealing>
The encapsulating epoxy resin composition of the present embodiment contains at least (A) epoxy resin, (B) allyl group-containing phenol novolac resin, and (C) inorganic filler. The encapsulating epoxy resin composition may be in powder form. The (B) phenol novolac resin having an allyl group has a higher viscosity than the general phenol novolac resin, but has a low softening point.

The encapsulating epoxy resin composition of the present embodiment is solid at room temperature and pressure. The shape is not limited, and may be any shape such as powder, granules, or tablets. The encapsulating epoxy resin composition of the present embodiment has a high filling property required as an underfill material when used for flip chip mounting. Therefore, since molding defects such as voids can be reduced, its industrial value is great. The encapsulating epoxy resin composition of the present embodiment has fine-pitch bumps, and is suitable for encapsulating a flip-chip-mounted semiconductor device having a large number of inputs/outputs (bumps).

In the present specification, normal temperature is 20° C., and normal pressure is atmospheric pressure. Below, each component contained in the epoxy resin composition for closure is explained in detail.

<(A) Epoxy resin>
The (A) epoxy resin is generally used in epoxy resin compositions for sealing and is not particularly limited. For example, phenol, cresol, xylenol, resorcin, catechol, including biphenyl type epoxy resin, phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, epoxy resin having triphenylmethane skeleton (triphenylmethane type epoxy resin), Acid catalysts of phenols such as bisphenol A and bisphenol F, naphthols such as α-naphthol, β-naphthol and dihydroxynaphthalene, and compounds having an aldehyde group such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde and salicylaldehyde Examples thereof include epoxidized novolak resins obtained by condensation or cocondensation below.

In addition, bisphenol A, bisphenol F, bisphenol S, diglycidyl ether such as alkyl-substituted or non-substituted biphenol, or stilbene-type epoxy resin, hydroquinone-type epoxy resin, polybasic acid such as phthalic acid, dimer acid, and epichlorohydrin Glycidyl ester type epoxy resin obtained, glycidyl amine type epoxy resin obtained by reaction of polyamines such as diaminodiphenylmethane, isocyanuric acid and epichlorohydrin, epoxidized product of co-condensation resin of dicyclopentadiene and phenols (dicyclopentadiene type epoxy resin) , Epoxy resin having naphthalene ring (naphthalene type epoxy resin), epoxide of aralkyl type phenol resin such as phenol/aralkyl resin, naphthol/aralkyl resin, trimethylolpropane type epoxy resin, terpene modified epoxy resin, peracetic acid of olefin bond Examples thereof include linear aliphatic epoxy resins, alicyclic epoxy resins, and sulfur atom-containing epoxy resins obtained by oxidation with peracids such as

One of these may be contained alone, or two or more may be contained in combination. Among these epoxy resins, from the viewpoints of reliability and moldability, it is preferable to include a biphenyl type epoxy resin or a low hygroscopic type epoxy resin in which a lower alkyl group is added to the phenyl ring. As such an epoxy resin, for example, one having an epoxy equivalent of 150 to 250 g/eq and a softening point or melting point of 50 to 130° C. is preferable.

From the viewpoint of filling property and reflow resistance, biphenyl type epoxy resin, bisphenol F type epoxy resin, stilbene type epoxy resin and sulfur atom-containing epoxy resin are preferable, and it is more preferable to increase the ratio of bisphenol F type epoxy resin. From the viewpoint of curability, a novolac type epoxy resin is preferable, from the viewpoint of low hygroscopicity, a dicyclopentadiene type epoxy resin is preferable, and from the viewpoint of heat resistance and low warpage, a naphthalene type epoxy resin and triphenylmethane. Type epoxy resins are preferable, and it is preferable to contain at least one of these epoxy resins.

Examples of the biphenyl type epoxy resin include epoxy resins represented by the following general formula (I). Examples of the bisphenol F type epoxy resin include epoxy resins represented by the following general formula (II). Examples of the stilbene type epoxy resin include epoxy resins represented by the following general formula (III). Examples of the sulfur atom-containing epoxy resin include epoxy resins represented by the following general formula (IV).

In formula (I), R ^{1 to} R ⁸ represent a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms. Each of the plurality of R ^{1 to} R ⁸ may be the same or different. n shows the integer of 0-3.

In the general formula (II), R ^{1 to} R ⁸ are a hydrogen atom, a substituted or unsubstituted C 1-10 alkyl group, a substituted or unsubstituted C 1-10 alkoxy group, a substituted or unsubstituted carbon An allyl group having 6 to 10 carbon atoms or a substituted or unsubstituted aralkyl group having 6 to 10 carbon atoms is shown. Each of the plurality of R ^{1 to} R ⁸ may be the same or different. n shows the integer of 0-3.

In formula (III), R ^{1 to} R ⁸ represent a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 5 carbon atoms. Each of the plurality of R ^{1 to} R ⁸ may be the same or different. n shows the integer of 0-10.

In formula (IV), R ^{1 to} R ⁸ represent a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms. Each of the plurality of R ^{1 to} R ⁸ may be the same or different. n shows the integer of 0-3.

Examples of the substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms include a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms and a substituted or unsubstituted allyl group having 6 to 10 carbon atoms. To be

Examples of the substituted or unsubstituted alkyl group having 1 to 10 carbon atoms include methyl group, ethyl group, propyl group, butyl group, isopropyl group, and isobutyl group. Examples of the substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.

Examples of the biphenyl type epoxy resin represented by the general formula (I) include 4,4′-bis(2,3-epoxypropoxy)biphenyl or 4,4′-bis(2,3-epoxypropoxy)-3. ,3',5,5'-Tetramethylbiphenyl-based epoxy resin, and epichlorohydrin and 4,4'-biphenol or 4,4'-(3,3',5,5'-tetramethyl) An epoxy resin obtained by reacting with biphenol can be mentioned. Among these, an epoxy resin containing 4,4'-bis(2,3-epoxypropoxy)-3,3',5,5'-tetramethylbiphenyl as a main component is preferable.

Examples of the bisphenol F type epoxy resin represented by the general formula (II) include, for example, R ¹ , R ³ , R ⁶ and R ⁸ are methyl groups, and R ² , R ⁴ , R ⁵ and R ⁷ are hydrogen atoms. Yes, a trade name YSLV-80XY (manufactured by Nippon Steel Chemical Co., Ltd.) containing n=0 as a main component is available as a commercial product.

The stilbene type epoxy resin represented by the above general formula (III) can be obtained by reacting the stilbene-based phenols, which are the raw materials, with epichlorohydrin in the presence of a basic substance. Examples of stilbene-based phenols as the raw material include 3-t-butyl-4,4'-dihydroxy-3',5,5'-trimethylstilbene, 3-t-butyl-4,4'-dihydroxy-3. ',5',6-Trimethylstilbene, 4,4'-dihydroxy-3,3',5,5'-tetramethylstilbene, 4,4'-dihydroxy-3,3'-di-t-butyl-5 , 5'-dimethylstilbene and 4,4'-dihydroxy-3,3'-di-t-butyl-6,6'-dimethylstilbene. Among these, 3-t-butyl-4,4'-dihydroxy-3',5,5'-trimethylstilbene and 4,4'-dihydroxy-3,3',5,5'-tetramethylstilbene are preferable. .. These stilbene type phenols may be contained alone or in combination of two or more.

Among the sulfur atom-containing epoxy resins represented by the general formula (IV), R ² , R ³ , R ⁶ and R ⁷ are hydrogen atoms, and R ¹ , R ⁴ , R ⁵ and R ⁸ are alkyl groups. An epoxy resin is preferred, and an epoxy resin in which R ² , R ³ , R ⁶ and R ⁷ are hydrogen atoms, R ¹ and R ⁸ are t-butyl groups, and R ⁴ and R ⁵ are methyl groups is more preferred. As such a compound, a trade name YSLV-120TE (manufactured by Nippon Steel Chemical Co., Ltd.) and the like are available as commercial products.

The epoxy resins represented by the general formulas (I) to (IV) may contain any one kind alone, or may contain two kinds or more in combination. The content is preferably 40% by mass or more, more preferably 60% by mass or more, and further preferably 80% by mass or more in total with respect to the total amount of the epoxy resin in order to exert its performance. preferable.

Examples of the novolac type epoxy resin include epoxy resins represented by the following general formula (V).

In the general formula (V), plural Rs each independently represent a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms. n shows the integer of 0-10.

The novolac type epoxy resin represented by the general formula (V) can be easily obtained by reacting a novolac type phenol resin with epichlorohydrin. Among them, R in the general formula (V) is a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, an isobutyl group or another alkyl group having 1 to 10 carbon atoms, a methoxy group, an ethoxy group. , An alkoxy group having 1 to 10 carbon atoms such as a propoxy group and a butoxy group are preferable, and a hydrogen atom or a methyl group is more preferable. n is preferably an integer of 0 to 3. Among the novolac type epoxy resins represented by the general formula (V), orthocresol novolac type epoxy resins are preferable.

When a novolac type epoxy resin is used, its content is preferably 20% by mass or more, and more preferably 30% by mass or more, based on the total amount of the epoxy resin in order to exert its performance.

Examples of the dicyclopentadiene type epoxy resin include epoxy resins represented by the following general formula (VI).

In general formula (VI), a plurality of R ^1's each independently represent a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and a plurality of R ^2's each independently represent. Represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms. n shows the integer of 0-10, m shows the integer of 0-6.

Examples of R ¹ in the general formula (VI) include a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, and a t-butyl group, a vinyl group, an allyl group, and a butenyl group. And other substituted or unsubstituted monovalent hydrocarbon groups having 1 to 5 carbon atoms such as alkenyl groups, halogenated alkyl groups, amino group-substituted alkyl groups, and mercapto group-substituted alkyl groups. Among these, an alkyl group such as a methyl group and an ethyl group and a hydrogen atom are preferable, and a hydrogen atom and a methyl group are more preferable.

Examples of R ² in the above formula (VI) include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group and a t-butyl group, an alkenyl group such as a vinyl group, an allyl group and a butenyl group. , A substituted or unsubstituted monovalent hydrocarbon group having 1 to 5 carbon atoms such as a halogenated alkyl group, an amino group-substituted alkyl group, and a mercapto group-substituted alkyl group. Among these, it is preferable that m is 0.

When a dicyclopentadiene type epoxy resin is used, its content is preferably 20% by mass or more, and more preferably 30% by mass or more, based on the total amount of the epoxy resin in order to exert its performance.

Examples of the naphthalene type epoxy resin include epoxy resins represented by the following general formula (VII). Examples of the triphenylmethane type epoxy resin include epoxy resins represented by the following general formula (VIII).

In formula (VII), R ^{1 to} R ³ represent a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms. Each of the plurality of R ^{1 to} R ⁴ may be the same or different. p is 1 or 0, and l and m each represent an integer of 0-11. Here, (l+m) is an integer of 1 to 11, and (l+p) is an integer of 1 to 12. i is an integer of 0 to 3, j is an integer of 0 to 2, and k is an integer of 0 to 4.

Examples of the naphthalene-type epoxy resin represented by the general formula (VII) include a random copolymer randomly containing 1 constitutional unit and m constitutional units, an alternating copolymer containing alternately, a copolymer containing regularly. Examples thereof include a block copolymer and a block copolymer containing them in the form of blocks. Any one of these may be contained alone, or two or more thereof may be contained in combination.

In general formula (VIII), a plurality of R's represent a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and n represents an integer of 1 to 10.

The epoxy resins represented by the above general formulas (VII) and (VIII) may contain any one kind alone or may contain two kinds or more in combination, but the content thereof exerts its performance. Therefore, the total amount of the epoxy resin is preferably 20% by mass or more, more preferably 30% by mass or more, and further preferably 50% by mass or more.

Any of the above-mentioned biphenyl type epoxy resin, bisphenol F type epoxy resin, stilbene type epoxy resin, sulfur atom-containing epoxy resin, novolac type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin and triphenylmethane type epoxy resin may be used. One may be contained alone, or two or more may be contained in combination.

<(B) Phenol novolac resin having an allyl group>
Along with the (A) epoxy resin, the (B) allyl group-containing phenol novolac resin (hereinafter, may be referred to as “(B) allylated phenol novolac resin” for convenience) contained in the encapsulating epoxy resin composition. It has a function as a curing agent for the above (A) epoxy resin, and refers to all monomers, oligomers and polymers having two or more phenolic hydroxyl groups in one molecule.

The (B) allylated phenol novolac resin preferably has a structure represented by the following general formula (i).

In the general formula (i), n represents an integer of 0 or more. The hydroxyl group equivalent of the (B) allylated phenol novolac resin is, for example, 140 to 200 g/eq and the softening point is 50 to 130°C.

The allyl group of the (B) allylated phenol novolac resin is preferably in the ortho position. The content of the phenol novolac resin (B) having an allyl group is preferably 3 to 15% by mass based on the whole epoxy resin composition for sealing, from the viewpoint of further increasing the flexural modulus. It is more preferably 10% by mass.

The (A) epoxy resin curing agent may include (B) allylated phenol novolac resin alone, or (B) other allyl phenol novolac resin in combination with another phenol resin or the like. Good. The content of the (B) allylated phenol novolac resin with respect to the total amount of the curing agent is preferably 30% by mass or more, and more preferably 40% by mass or more.

Other phenolic resins include, for example, phenols such as phenol, cresol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol and aminophenol, and/or naphthols such as α-naphthol, β-naphthol, dihydroxynaphthalene and formaldehyde. From novolac-type phenolic resins, phenols and/or naphthols and dimethoxyparaxylene or bis(methoxymethyl)biphenyl obtained by condensation or co-condensation with aldehyde-containing compounds such as benzaldehyde and salicylaldehyde under an acidic catalyst Synthesized phenol/aralkyl resins, aralkyl-type phenol resins such as naphthol/aralkyl resins, diclopentadiene-type phenol novolac resins, and dichropentadiene-type phenol novolac resins synthesized by copolymerization of phenols and/or naphthols and cyclopentadiene. Examples include pentadiene type phenolic resins and terpene modified phenolic resins.

Further, the (B) phenol novolac resin contained together with the allylated phenol novolac resin is preferably a biphenyl type phenol resin from the viewpoint of flame retardancy, and is preferably an aralkyl type phenol resin from the viewpoint of reflow resistance and curability. From the viewpoint of low hygroscopicity, dicyclopentadiene type phenolic resin is preferable, from the viewpoint of heat resistance, low expansion coefficient and low warp, triphenylmethane type phenolic resin is preferable, and from the viewpoint of curability, novolak Type phenolic resins are preferred. From the viewpoint of improving any of the above-mentioned characteristics, it is preferable to contain at least one of these phenol resins.

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

In formula (IX), R ^{1 to} R ⁹ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, or a substituted group. Alternatively, an unsubstituted allyl group having 6 to 10 carbon atoms, or a substituted or unsubstituted aralkyl group having 6 to 10 carbon atoms is shown. Each of the plurality of R ^{1 to} R ⁹ may be the same or different. n shows the integer of 0-3.

R ^{1 to} R ⁹ in the general formula (IX) preferably each independently have a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, an isobutyl group or the like having 1 to 10 carbon atoms. Alkyl group, methoxy group, ethoxy group, propoxy group, butoxy group, etc., C1-C10 alkoxy group, phenyl group, tolyl group, xylyl group, etc., C6-C10 allyl group, and benzyl group, phenethyl group. It is selected from an aralkyl group having 6 to 10 carbon atoms such as a group, and more preferably selected from a hydrogen atom and a methyl group.

Examples of the biphenyl type phenol resin represented by the general formula (IX) include compounds in which all of R ^{1 to} R ⁹ are hydrogen atoms. Among them, a mixture of condensates containing 50% by mass or more of a condensate having n of 1 or more is preferable from the viewpoint of melt viscosity. As such a compound, MEH-7851 (trade name, manufactured by Meiwa Kasei Co., Ltd.) is commercially available.

When a biphenyl type phenol resin is used, its content is preferably 30% by mass or more, more preferably 50% by mass or more, and more preferably 80% by mass with respect to the total amount of the curing agent in order to exert its performance. % Or more is more preferable.

Examples of the aralkyl type phenol resin include phenol/aralkyl resin and naphthol/aralkyl resin. Among these, a phenol/aralkyl resin represented by the following general formula (X) is preferable, and a phenol/aralkyl resin in which R in the general formula (X) is a hydrogen atom and the average value of n is 0 to 8 is more preferable. preferable. Specific examples thereof include p-xylylene type phenol/aralkyl resin and m-xylylene type phenol/aralkyl resin. When using these aralkyl type phenol resins, the content thereof is preferably 30 to 70% by mass, and more preferably 50 to 60% by mass based on the total amount of the curing agent in order to exert its performance. ..

In general formula (X), R represents a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and n represents an integer of 0 to 10.

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

In general formula (XI), plural R ^1's each independently represent a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and plural R ^2's each independently represent A substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms is shown. n shows the integer of 0-10, m shows the integer of 0-6.

When the dicyclopentadiene type phenol resin is contained, its content is preferably 30 to 70% by mass, and 50 to 60% by mass or more based on the total amount of the curing agent in order to exert its performance. Is more preferable.

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

In general formula (XII), plural Rs each independently represent a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and n represents an integer of 1 to 10.

When the triphenylmethane type phenol resin is contained, the content thereof is preferably 30 to 70% by mass, and preferably 50 to 60% by mass based on the total amount of the curing agent in order to exert its performance. More preferable.

Examples of the novolac type phenolic resin include phenol novolac resin, cresol novolac resin, and naphthol novolac resin. Among these, phenol novolac resin is preferable. (B) When containing a novolak type phenol resin different from the allylated phenol novolac resin, the content thereof is preferably 30 to 70% by mass relative to the total amount of the curing agent in order to exert its performance, 50 More preferably, it is from 60 to 60% by mass.

The above-mentioned biphenyl-type phenol resin, aralkyl-type phenol resin, dicyclopentadiene-type phenol resin, triphenylmethane-type phenol resin and novolac-type phenol resin may contain any one kind alone, or two or more kinds. You may include in combination. The content of the phenol resin is preferably 60% by mass or more, and more preferably 80% by mass or more, based on the total amount of the curing agent.

The melt viscosity of the (B) allylated phenol novolac resin at 150° C. is preferably 2 poises or less, more preferably 1 poise or less, from the viewpoint of filling property. Here, the melt viscosity refers to a viscosity measured by an ICI cone plate viscometer.

Equivalent ratio of (A) epoxy resin and (B) allylated phenol novolac resin, that is, ratio of number of hydroxyl groups in allylated phenol novolac resin to number of epoxy groups in epoxy resin (number of hydroxyl groups in allylated phenol novolac resin/ The number of epoxy groups in the epoxy resin is not particularly limited, but is preferably 0.5 to 2 and more preferably 0.6 to 1.3 in order to suppress the unreacted content of each. In order to obtain an epoxy resin composition for sealing which is excellent in moldability and reflow resistance, 0.8 to 1.2 is more preferable.

<(C) Inorganic filler>
Examples of the inorganic filler (C) contained in the epoxy resin composition for sealing together with the epoxy resin (A) and the allylated phenol novolac resin (B) include silica powder or alumina powder. Examples of the silica powder include fused silica powder and crystalline silica powder. These inorganic fillers may be contained alone or in combination of two or more. Among the above silica powders, it is particularly preferable to include fused silica powder from the viewpoint of high packing property and high fluidity. Examples of the fused silica powder include spherical fused silica powder and crushed fused silica powder. From the viewpoint of fluidity, it is preferable to include the spherical fused silica powder. Further, when thermal conductivity is required, it is preferable to contain alumina powder.

The inorganic filler (C) preferably has an average particle size of 1 to 100 μm from the viewpoint of improving fluidity. Furthermore, it is more preferable that the inorganic filler (C) has an average particle size of 3 to 30 μm and a particle size distribution in which particles having a particle size of 2 μm or less account for 5 to 40% by mass of the entire inorganic filler. As a result, the excellent narrow gap filling property of the mold underfill can be exhibited.

The average particle size and the particle size distribution of the inorganic filler (C) in the present specification are the same as JIS M 8100:1992 (powder lump mixture-general rules for sampling methods), in which the inorganic filler (fused spherical silica, etc.) is sampled, and the JIS An inorganic filler was prepared as a sample for measurement according to R 1622:1995 (general rules for sample preparation for measuring fine ceramic raw material particle size distribution), and JIS R 1629:1997 (particles of a fine ceramic raw material measured by a laser diffraction/scattering method). Diameter measurement method), using a laser diffraction particle size distribution analyzer SALD-7000 (laser wavelength: 405 nm) manufactured by Shimadzu Corporation, water is used as a solvent, and the refractive index of the inorganic filler is a real part 1. Under the condition of 45 and imaginary part 0.00, the particle diameter is measured with the volume as the reference.

If the average particle diameter of the inorganic filler (C) exceeds 30 μm, the filling property tends to decrease. Further, if the average particle diameter of the inorganic filler (C) is less than 3 μm, the melt viscosity increases and wire flow tends to occur. Further, in the particle size distribution of the inorganic filler (C), if the content of particles having a particle size of 2 μm or less is less than 5% by mass, the underfill filling property decreases, and if the content of particles having a particle size of 2 μm or less exceeds 40% by mass, it melts. Viscosity tends to increase.

The content of the inorganic filler (C) is preferably 60 to 92 mass% of the total epoxy resin composition, and more preferably 75 to 85 mass %. The volume fraction of the inorganic filler (C) is preferably 60 to 85% by volume, and more preferably 65 to 80% by volume. That is, if the content of the inorganic filler (C) is too small, the effect of reducing the water absorption rate by the inorganic filler becomes small, and the absolute value of the water absorption rate of the epoxy resin composition itself becomes large in the first place, resulting in high temperature and high temperature. Wet reliability tends to decrease. On the other hand, if the content of the inorganic filler (C) is too large, the fluidity of the epoxy resin composition tends to decrease, and wire flow and unfilling tend to occur.

In the epoxy resin composition for encapsulation (epoxy resin composition for semiconductor encapsulation) of the present embodiment, a curing accelerator, a coupling agent, a release agent, and carbon black may be added, if necessary, in addition to the above A to C. Other additives such as pigments and the like may be included as optional components.

As the curing accelerator, conventionally known ones are used. Specifically, tetraphenylphosphonium/tetraphenylborate, organic phosphorus compounds such as triphenylphosphine, imidazole compounds such as phenylimidazole, and 1,8-diazabicyclo(5.4.0)undecene-7,1, Examples thereof include diazabicycloalkene compounds such as 5-diazabicyclo(4.3.0)nonene-5. These may be contained alone or in combination of two or more. The content ratio of the curing accelerator is preferably 0.05 to 0.5 mass% of the entire encapsulating epoxy resin composition.

As the silane coupling agent, one having two or more alkoxy groups is preferably used. Specifically, 3-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-( 2-aminoethyl)aminopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-anilinopropyltrimethoxysilane, and hexamethyldisilazane. These may be contained alone or in combination of two or more.

Examples of the release agent include higher fatty acids, higher fatty acid esters, and higher fatty acid calcium compounds. Examples include carnauba wax and polyethylene wax. These may be contained alone or in combination of two or more.

Further, for the purpose of improving the reliability in the humidity resistance reliability test, an ion trap agent such as hydrotalcites or magnesium hydroxide may be included.

The epoxy resin composition for sealing of the present embodiment can be manufactured, for example, as follows. That is, (A) epoxy resin, (B) allylated phenol novolac resin, (C) inorganic filler, and if necessary, other additives are appropriately blended according to a conventional method, and a kneading machine such as a mixing roll machine is used. Is melt-kneaded in a heated state to obtain a kneaded product. Then, the kneaded product is cooled and solidified at room temperature. Then, it is crushed by a known means and tableted if necessary. The target epoxy resin composition for encapsulation can be manufactured by such a series of steps.

<Semiconductor device>
Next, the semiconductor device of this embodiment will be described. In addition, suitable applications and usages of the encapsulating epoxy resin composition of the present embodiment will be described through the description of the semiconductor device.

The semiconductor device of this embodiment is a semiconductor device including an element sealed with a cured product of the above-mentioned sealing epoxy resin composition. A semiconductor device includes, for example, a supporting member such as a lead frame, a pre-wired tape carrier, a wiring board, glass, and a silicon wafer, an element mounted on the supporting member, and a curing of an epoxy resin composition for sealing the element. And a thing.

Examples of the element include active elements such as semiconductor chips, transistors, diodes, and thyristors, and passive elements such as capacitors, resistors, and coils. A semiconductor device is manufactured through a process in which such an element is sealed with the epoxy resin composition according to the above embodiment.

As a specific example of the semiconductor device, a semiconductor chip is encapsulated with the epoxy resin composition according to the above-described embodiment, TCP (Tape Carrier Package); wire bonding, flip-chip bonding, wiring on a wiring board or glass. A COB (an active element such as a semiconductor chip, a transistor, a diode, or a thyristor connected by solder or the like, and/or a passive element such as a capacitor, a resistor, or a coil is sealed with the epoxy resin composition according to the above-mentioned embodiment. Chip On Board module; Hybrid IC; Multi-chip module; Device is mounted on the surface of the organic substrate having terminals for wiring board connection formed on the back surface, and the device and the wiring formed on the organic substrate are connected by bumps or wire bonding. After that, BGA (Ball Grid Array), CSP (Chip Size Package), etc., in which an element is sealed with the epoxy resin composition according to the above-mentioned embodiment, are exemplified. Further, the epoxy resin composition according to the above embodiment can be effectively used in a printed circuit board.

The contents of the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(Examples 1-2, reference examples 1-2, comparative examples 1-2)
<Preparation of epoxy resin composition for sealing>
(A) Epoxy resin The following was used as the epoxy resin.
Epoxy resin 1: o-cresol novolac type epoxy resin, manufactured by Nippon Kayaku Co., Ltd., trade name: EOCN-1020, epoxy equivalent: 195 g/eq, melting point: 67° C.
Epoxy resin 2: epoxy resin, Hitachi Chemical Co., Ltd., trade name: PYB-3K2, epoxy equivalent: 192 g/eq, melting point: 106°C.
Epoxy resin 3: biphenyl type epoxy resin, manufactured by Japan Epoxy Resin Co., Ltd., trade name: Epicoat YX-4000H, epoxy equivalent: 196 g/eq, melting point: 106° C.

(B) Curing agent The following were used as a curing agent.
-Curing agent 1: Phenol-xylylene resin, manufactured by Meiwa Kasei Co., Ltd., trade name: MEHC-7800SS, hydroxyl group equivalent: 170 g/eq, softening point: 65°C.
-Curing agent 2: Phenolic resin, manufactured by Hitachi Chemical Co., Ltd., trade name: HPM-J3, hydroxyl group equivalent: 120 g/eq, softening point: 90°C.
-Curing agent 3: Phenol novolac resin, manufactured by Meiwa Kasei Co., Ltd., trade name: MEH-5000S, hydroxyl group equivalent: 168 g/eq, softening point: 73°C.

(C) Inorganic filler The following was used as the inorganic filler.
Inorganic filler 1: fused silica, average particle size: 17 μm, manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: FB-9454FC
Inorganic filler 2: fused silica, average particle size: 0.7 μm, manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: SFP-30M

(D) Coupling agent The following was used as a coupling agent.
-Coupling agent: 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-403

The following were used as other additives.
-Curing accelerator: Addition product of tributylphosphine and benzoquinone-Colorant: Carbon black (Mitsubishi Chemical Co., Ltd., trade name: MA-600MJ)
-Release agent: Hoechst wax (Clariant, trade name: HW-E)
・Ion trap agent (trade name: HT-P, manufactured by Sakai Chemical Industry Co., Ltd.)

The respective components were blended in the proportions shown in Table 1, sufficiently mixed with a mixer, and then melt-kneaded for 2 minutes at about 100° C. using a biaxial kneader. After cooling this melt, the solidified powder was pulverized into powder to prepare powdery epoxy resin compositions of Examples 1-2, Reference Examples 1-2, and Comparative Examples 1-2, respectively. .. Unless otherwise specified, the compounding unit in Table 1 is part by mass. In addition, "-" indicates that it is unassigned. In Table 1, the filler amount (Vf) indicates the volume fraction (volume %) of the inorganic filler contained in the powdery epoxy resin composition.

Using the epoxy resin compositions of Examples, Reference Examples and Comparative Examples thus obtained, each evaluation was performed according to the methods described below.

<Evaluation>
(1) Coefficient of linear expansion (α1, α2) and glass transition temperature (Tg)
The epoxy resin compositions of Examples, Reference Examples and Comparative Examples were molded using a transfer molding machine and cured to prepare trapezoidal test pieces (20 mm×lower side 5 mm, upper side 4 mm×3 mm). Molding and curing were performed under conditions of a molding temperature of 175° C. and a molding time of 90 seconds. Post-curing was performed at 175° C. for 5 hours.

Using a TMA high-precision two-sample thermal analysis (Seiko Instruments, trade name: SS6100), a linear expansion coefficient (α) and a glass transition temperature (Tg) of the test piece under the conditions of a load of 10 g and a heating rate of 5°C/min. And were measured. The linear expansion coefficient (α) between the two measured temperatures is calculated by the following formula.

α=1/(LΔt)
L=length of test piece at room temperature (mm)
l = elongation (mm)
Δt = measurement temperature difference (°C)

The linear expansion coefficient α between the two measurement temperatures of 80° C. and 100° C. was α1, and the linear expansion coefficient α between the two measurement temperatures of 200° C. and 230° C. was α2. The glass transition temperature was the temperature at the intersection of both straight lines. The results are shown in Table 2.

(2) Bending Strength/Bending Elastic Modulus The epoxy resin compositions of each Example, each Reference Example and each Comparative Example were molded and cured under the same conditions as in (1) above, and a rectangular parallelepiped test piece (length x Width×height=80 mm×10 mm×4 mm) was produced. The tensile test of this test piece was performed using a universal tensile tester TENSILON under the conditions of a load speed of 5 mm/min and a temperature of 260°C. Then, the bending strength and the bending elastic modulus were calculated by the following formulas. The results are shown in Table 2.

бf=(3PLv)/(2Wh ² )
Ef=(Lv ³ m)/(4Wh ³ )
бf: Bending strength (MN/m ² )
Ef: Flexural modulus (GN/m ² )
P: Load when the test piece is broken (N)
Lv: Distance between fulcrums (m)
W: width of test piece (m)
h: Height of test piece (m)
m: Gradient (N/m) of tangent line of initial straight line portion of load-deflection curve

Compared to the epoxy resin compositions containing the curing agent 3 (Examples 1 and 2 and Reference Examples 1 and 2), the epoxy resin compositions containing no curing agent 3 (Comparative Examples 1 and 2) had a high-temperature flexural modulus. It was small. The epoxy resin compositions containing the curing agent 3 (Examples 1 and 2 and Reference Examples 1 and 2) had a high bending elastic modulus at high temperature while maintaining a large α1. Moreover, when the content of the curing agent 3 increased, the linear expansion coefficient α1 and the high temperature bending elastic modulus tended to improve.

Therefore, by using the epoxy resin composition of the present invention, the elastic modulus at the reflow temperature can be increased while increasing the linear expansion coefficient α1 from the molding temperature to room temperature. Therefore, it is possible to reduce the thermal stress generated due to the difference in the coefficient of linear expansion between the sealing resin and the package constituent member such as the substrate, and the difference in the elastic modulus. Therefore, it is possible to suppress the warp of the package.

According to the present disclosure, a sealing epoxy resin composition capable of forming a cured product having a large thermal shrinkage (linear expansion coefficient: CTE1) from the molding temperature to room temperature and having a high elastic modulus during a reflow process. Will be provided. Further, by using the encapsulating epoxy resin composition, a semiconductor device in which warpage is suppressed and a method for manufacturing such a semiconductor device are provided.

Claims (9)

(A) Epoxy resin,
(B) curing agent, and (C) inorganic filler,
An epoxy resin composition for sealing which is solid at room temperature and atmospheric pressure, including:
The (A) epoxy resin includes an ortho-cresol novolac type epoxy resin,
The curing agent (B) contains a phenol novolac resin having an allyl group,
The phenol novolac resin having an allyl group,
It has a structure represented by the following general formula (i), the allyl group is in the ortho position, and the hydroxyl equivalent is 140 to 200 g/eq,
The flexural modulus (260° C.) of the cured product when molded and cured under the conditions of a molding temperature of 175° C. and a molding time of 90 seconds and post-cured at 175° C. for 5 hours is 1.55 GPa or more. Stopping epoxy resin composition.

[In the formula (i), n represents an integer of 0 or more. ] The epoxy resin composition for encapsulation according to claim 1, wherein the curing agent (B) contains a phenol/aralkyl resin having a structure represented by the following general formula (X).

[In the formula (X), R represents a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and n represents an integer of 0 to 10. ] The epoxy resin composition for encapsulation according to claim 2, wherein the content of the phenol/aralkyl resin with respect to the total amount of the (B) curing agent is 30 to 70% by mass. The epoxy resin composition for encapsulation according to claim 1, wherein the epoxy resin (A) contains a biphenyl type epoxy resin. The epoxy resin composition for encapsulation according to claim 1, wherein the content of the phenol novolac resin having an allyl group is 3 to 15 mass %. The epoxy resin composition for encapsulation according to claim 1, wherein the content of the inorganic filler (C) is 75 to 85 mass %. The average particle size of the (C) inorganic filler is 3 to 30 μm, and the particle size distribution is such that particles having a particle size of 2 μm or less account for 5 to 40% by mass of the entire (C) inorganic filler. The epoxy resin composition for encapsulation according to any one of 1. A semiconductor device comprising an element encapsulated with the cured product of the epoxy resin composition for encapsulation according to claim 1. A method for manufacturing a semiconductor device, comprising a step of encapsulating an element with the encapsulating epoxy resin composition according to claim 1.