JP2003082068A - Epoxy resin composition and semiconductor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition that has excellent crack resistance and high adhesion and the semiconductor devices sealed with the cured product of the epoxy resin. SOLUTION: The epoxy resin composition comprises (A) an epoxy resin, (B) a curing agent and (C) a filler wherein (B) the curing agent is phenolic compounds bearing the recurring unit structures represented by specific chemical formulas (I) (wherein R1 -R4 are each H or methyl) and (II) (R5 -R8 are each H or methyl). In addition, the content of (C) the filler is 80-96 wt.% in the resin composition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an epoxy resin composition which is excellent in moldability and reliability and is particularly suitable for semiconductor encapsulation.

[0002]

2. Description of the Related Art Epoxy resins are excellent in heat resistance, moisture resistance, electrical characteristics and adhesiveness, and can be added with various characteristics by compounding formulation, so they are used as industrial materials such as paints, adhesives and electrical insulation materials. Has been done.

For example, as a sealing method for electronic circuit parts such as semiconductor devices, hermetic sealing by metal or ceramics and resin sealing by phenol compound, silicone resin, epoxy resin, etc. have been proposed conventionally. The resin used for such sealing is called a sealing material resin. Among them, the resin encapsulation with an epoxy resin is most actively used from the viewpoint of the balance of economic efficiency, productivity and physical properties. As a sealing method using an epoxy resin, a method of using a composition obtained by adding a curing agent, a filler, etc. to an epoxy resin, setting a semiconductor element in a mold, and sealing by a transfer molding method is generally performed. It is being appreciated.

The characteristics required of the epoxy resin composition for semiconductor encapsulation include reliability and moldability.
As for reliability, solder heat resistance, high temperature reliability, heat resistance reliability,
Moisture resistance and the like include moldability such as fluidity, hot hardness, and burrs.

Recently, the mounting of semiconductor device packages on a printed circuit board has been promoted with higher density and automation. Instead of the conventional "insertion mounting method" in which lead pins are inserted into holes in the board, the semiconductor device package is mounted on the surface of the board. "Surface mounting method" for soldering solder has become popular. Along with this, the semiconductor device package has changed from the conventional DIP (dual in-line package) to a thin FPP (flat plastic package) suitable for high-density mounting and surface mounting.
Package). Among them, recently
Due to advances in fine processing technology, TSO with a thickness of 2 mm or less
P, TQFP and LQFP are becoming mainstream. Therefore, it becomes more susceptible to external influences such as humidity and temperature, and reliability such as solder heat resistance, high temperature reliability, and heat resistance reliability will become more important in the future.

In surface mounting, solder reflow is usually used for mounting. In this method, a semiconductor device package is placed on a substrate, exposed to a high temperature of 200 ° C. or higher, and the solder previously attached to the substrate is melted to bond the semiconductor device package to the surface of the substrate. In such a mounting method, the entire semiconductor device package is exposed to high temperature. At this time, stress such as thermal stress is applied between the sealing resin and each member such as the lead frame and the semiconductor chip inside the package. At this time, if the adhesiveness of the sealing resin is poor, peeling occurs between the sealing material and the members inside the package.
When peeling occurs, cracks are generated starting from the peeling, or moisture is deposited on the peeled portion, which lowers the reliability of the semiconductor. Therefore, the adhesiveness to the member is very important in the semiconductor sealing resin.

Further, in recent years, lead-free solders containing no lead have been used from the viewpoint of environmental protection. Lead-free solder has a high melting point, and therefore the reflow temperature also rises, so that the semiconductor sealing resin is required to have higher adhesiveness than ever.

[0008]

An object of the present invention is to provide a resin composition having high adhesion to a semiconductor package member and having excellent reliability such as crack resistance during reflow, so The purpose is to enable a resin-sealed semiconductor corresponding to the reflow temperature.

[0009]

In order to solve the above problems, the present invention mainly has the following configuration. That is,
"Epoxy resin (A), curing agent (B) and filler (C)
An epoxy resin composition comprising: a curing agent (B) containing a phenol compound having a repeating unit structure represented by the following chemical formulas (I) and (II). Resin composition.

[0010]

[Chemical 5] (R _{1 to} R ₄ represent a hydrogen atom or a methyl group.)

[0011]

[Chemical 6] (R _{5 to} R ₈ represent a hydrogen atom or a methyl group.) ”.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The constitution of the present invention will be described in detail below.

The epoxy resin composition of the present invention contains an epoxy resin (A), a curing agent (B) and a filler (C).

The epoxy resin (A) in the present invention is not particularly limited as long as it has two or more epoxy groups in one molecule, and specific examples thereof include, for example, cresol novolac type epoxy resin and bishydroxybiphenyl type. Epoxy resin, bisphenol A type epoxy resin,
Bisphenol F type epoxy resin, linear aliphatic type epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin,
Examples thereof include halogenated epoxy resins and spiro ring-containing epoxy resins.

Among them, the biphenyl type epoxy represented by the chemical formula (III) and the bisphenol type epoxy represented by the chemical formula (IV), which have good adhesion to the lead frame member, are preferable.

[0016]

[Chemical 7] (In the formula, R _{9 to} R ₁₂ represent a hydrogen atom or a methyl group.)

[0017]

[Chemical 8] (In the formula, R _{13 to} R ₁₈ represent a hydrogen atom or a methyl group.)

Two or more kinds of epoxy resins may be used in combination depending on the application, but for the purpose of sealing a semiconductor device, a biphenyl type epoxy or a bisphenol type epoxy may be used alone or in combination, and all epoxy resins (A ) In 5
It is preferable to contain 0% by weight or more.

The compounding amount of the epoxy resin (A) is usually 5.0 to 10.0% by weight based on the whole composition.

The curing agent (B) in the present invention contains a phenol compound (b) having a repeating unit structure represented by the chemical formulas (I) and (II) as an essential component.

[0021]

[Chemical 9] (R _{1 to} R ₄ represent a hydrogen atom or a methyl group.)

[0022]

[Chemical 10] (R _{5 to} R ₈ represent a hydrogen atom or a methyl group.)

By using the phenol compound having the repeating unit structure represented by the chemical formulas (I) and (II), the adhesiveness of the resin composition is improved and the crack resistance is significantly improved.

The phenol compound having the repeating unit structure represented by the chemical formulas (I) and (II) has the formula (I)
Is a polymer in which the repeating unit of the biphenyl derivative represented by and the repeating unit of the xylene derivative represented by the chemical formula (II) are bonded. Of these, a random copolymer in which these units are randomly bonded is preferable. The method for producing the random copolymer is not particularly limited, and the random copolymer is produced in the same manner as a known phenol resin. However, the number of moles of repeating units of the biphenyl derivative represented by the chemical formula (I) in the polymer and the chemical formula ( The ratio of the number of moles of the repeating unit of the xylene derivative represented by II) is preferably 30:70 to 70:30, and particularly, the ratio of the starting materials at the time of polymerization is about equal to 45:55 to 55:45. It is preferable to make the number of moles the same. Further, the hydroxyl equivalent of this random copolymer is preferably about 180 to 200.
The end of the polymer may be end-capped with any compound, but is preferably end-capped with phenol.

Each homopolymer, that is, only the polymer having only the repeating unit represented by the chemical formula (I) (biphenyl-containing phenol aralkyl resin) or the polymer having only the repeating unit represented by (II) (phenol aralkyl resin) was used. In this case, the adhesiveness is insufficient when the phenol aralkyl resin alone is used, and the crack resistance is insufficient when the biphenyl-containing phenol aralkyl resin alone is used. Further, when these homopolymers are mixed and used, although the adhesion and crack resistance are slightly improved, they are not always sufficient. There is also the problem of reduced fluidity.

On the other hand, by using the phenolic compound having the repeating unit structure represented by the chemical formulas (I) and (II), the adhesion and the crack resistance are greatly improved and the fluidity is not lowered.

The viscosity of the phenolic compound having the repeating unit structure represented by the chemical formulas (I) and (II) is 15
From the viewpoint of fluidity, it is preferable that the ICI viscosity at 0 ° C. is 2 poise or less, further 1 poise or less.

The curing agent (B) may be 2 depending on the use.
Although more than one type of curing agent may be used in combination, the type is not particularly limited as long as it reacts with the epoxy resin (A) and is cured, and specific examples of the curing agent that can be used in combination include, for example, phenol. Novolak resins such as novolac and cresol novolac, bisphenol compounds such as bisphenol A, acid anhydrides such as maleic anhydride, phthalic anhydride, and pyromellitic dianhydride, and aromatic amines such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone. Can be given. Among them, a curing agent having a phenolic hydroxyl group is preferable for sealing a semiconductor device because of its excellent heat resistance, moisture resistance and storage stability. Specific examples of the curing agent having a phenolic hydroxyl group include novolac resins such as phenol novolac resin, cresol novolac resin and naphthol novolac resin, tris (hydroxyphenyl) methane, 1,1,2-tris (hydroxyphenyl) ethane, 1 , 1,3-tris (hydroxyphenyl) propane, a condensation compound of terpene and phenol, a dicyclopentadiene skeleton-containing phenol resin, a phenol aralkyl resin, and a naphthol aralkyl resin.

The compounding amount of the curing agent (B) to the total epoxy resin composition is usually 2.5 to 10% by weight, and the compounding ratio of the epoxy resin (A) and the curing agent (B) is usually 1. It is 5 to 0.5.

Further, in the present invention, the epoxy resin (A)
A curing catalyst may be used to accelerate the curing reaction of the curing agent (B). The curing catalyst is not particularly limited as long as it accelerates the curing reaction, and for example, 2-methylimidazole,
Imidazole compounds such as 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole, triethylamine, benzyldimethylamine, α-methylbenzyl Methylamine, 2- (dimethylaminomethyl) phenol,
Tertiary amine compounds such as 2,4,6-tris (dimethylaminomethyl) phenol, 1,8-diazabicyclo (5,4,0) undecene-7 and salts thereof, zirconium tetramethoxide, zirconium tetrapropoxide, Organometallic compounds such as tetrakis (acetylacetonato) zirconium and tri (acetylacetonato) aluminum, and triphenylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, Organic phosphine such as tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetrabenzoic acid borate, tetraphenylphosphonium tetranaphthoic acid borate Emissions compounds and such salts thereof. Particularly preferred are triphenylphosphine, 1,8-diazabicyclo (5,4,0) undecene-7, tetraphenylphosphonium tetraphenylborate and the like.

Two or more of these curing catalysts may be used in combination depending on the intended use, and the compounding amount is preferably in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the epoxy resin (A).

The type of the filler (C) in the present invention is preferably spherical silica (c), and the proportion thereof is the filler (C).
It is preferably 80% by weight or more based on the whole. Generally, as the proportion of the filler (C) increases, the moldability such as fluidity deteriorates, but by using the spherical silica (c), the deterioration of fluidity can be further suppressed.
Regarding the particle size of the spherical silica (c), the average particle size (median size) is preferably 20 μm or less.

The blending ratio of the filler (C) is preferably 80 to 96% by weight in the total resin composition. Further, since it is possible to deal with "lead-free solder" such that the solder reflow temperature becomes 260 ° C, it is more preferable that the proportion of the filler (C) is 85% by weight or more and 96% by weight or less. . When the proportion of the inorganic substance in the entire resin composition is high in this way, the flame retardancy becomes high and the flame retardancy can be maintained without using the conventionally used flame retardant. This eliminates the need to add a halogen component, which has been conventionally used as a flame retardant, to the resin composition, which is preferable from the viewpoint of environmental protection. From the viewpoint of environmental protection, the content of Br atom is 0.1% by weight or less based on the whole composition, and Sb
The content of atoms is preferably 0.05% by weight or less with respect to the entire composition, and both are particularly preferably 0.01% by weight or less with respect to the entire composition.

Two or more kinds of fillers may be used in combination depending on the use. As the fillers used in combination, inorganic fillers are preferable, and specifically, fused silica, crystalline silica,
Examples thereof include calcium carbonate, magnesium carbonate, alumina, magnesia, clay, talc, calcium silicate, titanium oxide, asbestos and glass fiber. The shape and average particle size of the fillers used in combination are not particularly limited, but spherical is preferable from the viewpoint of fluidity and moldability, and the average particle size is preferably 20 μm or less.

In the present invention, it is preferable to add a silane coupling agent (D) for the purpose of improving reliability. As the silane coupling agent (D), a known silane coupling agent can be used. Specific examples thereof include γ-glycidoxypropyltrimethoxysilane,
γ-glycidoxypropylmethyldiethoxysilane, N
-Β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ -Mercaptopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane and the like are mentioned, and two or more kinds may be added depending on the use.
When adding two or more silane coupling agents,
It is preferable to use γ-aminopropyltrimethoxysilane or γ-mercaptopropyltrimethoxysilane as one of them because the effect of improving reliability is large.

The compounding amount of the silane coupling agent (D) is
From the viewpoint of moldability and reliability, usually 0.1 to 5 parts by weight, preferably 0.2 to 3 parts by weight, relative to 100 parts by weight of the filler,
It is particularly preferably 0.3 to 1.5 parts by weight. The silane coupling agent (D) can be added by mixing with other components, but in the present invention, the surface treatment of the filler (C) with the silane coupling agent (D) in advance, It is preferable in terms of improving reliability, adhesiveness and fluidity.

The epoxy resin composition of the present invention includes a coloring agent such as carbon black and iron oxide, silicone rubber,
Styrene block copolymers, olefin polymers, elastomers such as modified nitrile rubber and modified polybutadiene rubber, thermoplastic resins such as polystyrene, coupling agents such as titanate coupling agents, long chain fatty acids, metal salts of long chain fatty acids. A long-chain fatty acid ester, a long-chain fatty acid amide, a release agent such as paraffin wax, and a cross-linking agent such as an organic peroxide can be optionally added.

The epoxy resin composition of the present invention is preferably produced by melt kneading. Specifically, the raw materials are mixed to some extent with a mixer or the like, and the mixed raw materials are mixed at a temperature of 60 to 140 ° C. using a known kneading method such as Banbury mixer, kneader, roll, single-screw or twin-screw extruder, and cokneader. It is manufactured by melt-kneading in the temperature range of. This epoxy resin composition is usually used in the form of powder or tablet for molding a semiconductor by molding. As a method for sealing the semiconductor element, a low-pressure transfer molding method is generally used, but an injection molding method or a compression molding method is also possible. The molding conditions include, for example, an epoxy resin composition at a molding temperature of 1
A semiconductor device is manufactured by molding at 50 ° C. to 200 ° C., a molding pressure of 5 to 15 MPa, and a molding time of 30 to 300 seconds to obtain a cured product of an epoxy resin composition. Further, if necessary, the above-mentioned molded product is subjected to additional heat treatment at 100 to 200 ° C for 2 to 15 hours.

[0039]

EXAMPLES The present invention will be specifically described below with reference to examples. [Examples 1 to 18, Comparative Examples 1 to 4] The raw materials used in the present invention are as follows. <Epoxy resin I> Bisphenol F type epoxy resin (epoxy equivalent 192) represented by the following chemical formula (IV)

[0040]

[Chemical 11] <Epoxy resin II>4,4'-bis (2,3-epoxypropoxy) -3,3 ', 5,5'-tetramethylbiphenyl (epoxy equivalent 193) <Epoxy resin III> o-cresol novolac type epoxy Resin (Epoxy equivalent 194) <Curing agent I> Phenolic compound in which repeating unit structures represented by the following chemical formulas (I) and (II) are randomly bonded (repeating units of the chemical formulas (I) and (II) in the molecule) Is about 50:50, R1 to R8 are all hydrogen atoms, MEH-7860SS manufactured by Meiwa Kasei, hydroxyl equivalent 18
7, ICI viscosity (150 ° C) 0.75 Pa · s)

[0041]

[Chemical 12]

[0042]

[Chemical 13] <Curing agent II> Phenol novolac resin having a hydroxyl equivalent of 108 <Curing agent III> Phenol aralkyl resin having a hydroxyl equivalent of 175 <Curing agent IV> A phenol curing agent represented by the following chemical formula having a hydroxyl equivalent of 203 (ICI viscosity (175 ℃) 0.07
Pa · s)

[0043]

[Chemical 14] (However, 90% by weight of the component having n of 1 to 3 is included.) <Inorganic filler> Amorphous spherical fused silica having an average particle size of about 10 μm <Silane coupling agent I> N-phenyl-γ-aminopropyltri Methoxysilane <silane coupling agent II> γ-glycidoxypropyltrimethoxysilane <silane coupling agent III> γ-aminopropyltrimethoxysilane <silane coupling agent IV> γ-mercaptopropyltrimethoxysilane <silane coupling Agent V> γ-ureidopropyltriethoxysilane (silane coupling agent was previously mixed with the inorganic filler.) <Curing accelerator I> Triphenylphosphine <Curing accelerator II> 1,8-diazabicyclo (5 , 4,
0) Undecene-7 <Curing accelerator III> Tetraphenylphosphonium tetraphenylborate <Curing accelerator IV> Tetraphenylphosphonium tetranaphthoic acid borate <Curing accelerator V> Tetraphenylphosphonium tetrabenzoic acid borate <Colorant> Carbon Black (the same compounding amount is 0.2% by weight based on the resin composition) <Release agent> Carnauba wax (The same compounding amount is 0.3% by weight based on the resin composition) Table 1 shows each component. The composition ratio was dry blended with a mixer. This was heated and kneaded for 5 minutes using a mixing roll having a roll surface temperature of 90 ° C., cooled and pulverized to produce an epoxy resin composition for semiconductor encapsulation. Since the amounts of the silane coupling agent, carbon black and carnauba wax to be added to the composition were uniform, they were omitted from the table. The numbers in the table represent% by weight.

Next, using this resin composition, a low pressure transfer molding method was performed at 175 ° C. and a cure time of 90.
176pin LQ with a chip size of 10 x 10 mm, equipped with a simulated device with a nitride film on the surface under the condition of seconds
FP (outer shape: 24 × 24 × 1.4 mm, frame material:
Molded copper, lead frame part: silver plating) 175
Post-curing was carried out under the conditions of 4 ° C. for 4 hours, and the physical properties of each resin composition were evaluated by the following physical property measuring methods. The post cure was 175 ° C. for 4 hours. Crack resistance: Molded 20 pieces of 176pin LQFP,
After post-curing, after humidifying at 85 ° C./60% RH for 168 hours, heat treatment was performed for 2 minutes in an IR reflow furnace having a maximum temperature of 260 ° C., and the number of packages with external cracks was visually examined. Adhesion: Molded 20 pieces of 176pin LQFP, post-cured, and humidified at 85 ° C./60% RH for 168 hours,
After heat treatment for 2 minutes in an IR reflow furnace with a maximum temperature of 260 ° C., the ultrasonic wave flaw detector (manufactured by Hitachi Construction Machinery Co., Ltd. “mi-s”
and the number of packages in which peeling occurred was checked for each of them. Moldability: The appearance of the molded 176pin LQFP was visually observed to check whether there was any unfilled or void, and those without unfilled or void were regarded as good. Flame retardance test: 5 ″ × 1/2 ″ × 1/16 ″ combustion test pieces were molded under conditions of 175 ° C. and 90 seconds of curing time. After post-curing under conditions of 175 ° C. and 4 hours, UL94 standard. The flame retardancy was evaluated according to.

Tables 1 to 5 show the evaluation results.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

[0049]

[Table 4]

[0050]

[Table 5]

As shown in Tables 1 to 5, the epoxy resin composition of the present invention is excellent in crack resistance and adhesion.
On the other hand, in the comparative examples not containing the phenol compound represented by the chemical formula (I), the adhesion and crack resistance are inferior, and when the mixture of the homopolymer is used as the curing agent, the formability is inferior.

As described above, it can be seen that sufficient performance is exhibited by adding the specific phenolic curing agent.

[0053]

EFFECT OF THE INVENTION An epoxy resin composition comprising an epoxy resin (A), a curing agent (B) and a filler (C), wherein the curing agent (B) is represented by the following chemical formulas (I) and (II) By containing a phenol compound having a repeating unit structure represented by (4), an epoxy encapsulant having excellent crack resistance and adhesiveness can be obtained.

[0054]

[Chemical 15] (R _{1 to} R ₄ represent a hydrogen atom or a methyl group.)

[0055]

[Chemical 16] (R _{5 to} R ₈ represent a hydrogen atom or a methyl group.)

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) H01L 23/31 F Term (Reference) 4J002 CD001 CD051 CE002 DE076 DE146 DJ026 DJ036 DJ046 DL006 EN048 EU118 EU138 EW018 EW178 EX037 EX057 EX067 EX077 EX087 FA086 FD016 FD090 FD140 FD142 FD158 FD160 GQ05 4J036 AA02 AC02 AC03 AC06 AC08 AC15 AD07 AD08 BA02 BA03 DB03 DC05 DC41 DC46 DD07 FA05 FA10 FA12 FA13 FB06 GA04 GA07 GA16 GA17 GA28 JA07 KA05 4M109 EA02 EB09 EB09 EB09EB02

Claims (8)

[Claims] 1. An epoxy resin composition comprising an epoxy resin (A), a curing agent (B) and a filler (C), wherein the curing agent (B) is represented by the following chemical formulas (I) and (II). ] The epoxy resin composition containing the phenol compound which has a repeating unit structure represented by these. [Chemical 1] (R _{1 to} R ₄ represent a hydrogen atom or a methyl group.) (R _{5 to} R ₈ represent a hydrogen atom or a methyl group.) 2. The epoxy resin composition according to claim 1, wherein the amount of the filler (C) is 80 to 96% by weight. 3. The epoxy resin composition according to claim 1, further comprising a silane coupling agent (D). 4. The epoxy resin (A) has the following chemical formula (III):
The epoxy resin composition according to any one of claims 1 to 3, comprising an epoxy compound represented by: [Chemical 3] (In the formula, R _{9 to} R ₁₂ represent a hydrogen atom or a methyl group.) 5. The epoxy resin composition according to any one of claims 1 to 4, wherein the epoxy resin (A) contains an epoxy compound represented by the following chemical formula (IV). [Chemical 4] (In the formula, R _{13 to} R ₁₈ represent a hydrogen atom or a methyl group.) 6. The content of Br atom is 0.1% by weight or less with respect to the entire resin composition, wherein the content is 1 to 5.
The epoxy resin composition according to any one of 1. 7. The content of Sb atoms is 0.05% by weight or less based on the whole resin composition.
The epoxy resin composition according to any one of 6 above. 8. A semiconductor device, which is encapsulated with the cured product of the epoxy resin composition according to any one of claims 1 to 7.