JP2000230111A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition for semiconductor sealing use which contains neither halogen nor antimony and is excellent in moldability, flame retardancy, high-temperature preservation characteristics and moisture resistance reliability. SOLUTION: This epoxy resin composition for semiconductor sealing use is characterized by essentially comprising an epoxy resin, a phenolic resin, a curing accelerator, an inorganic filler, a fused spherical silica or talc coated with zinc molybdate, and zinc borate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for semiconductor encapsulation which does not contain a halogen-based flame retardant and an antimony compound and has excellent flame retardancy and high-temperature storage characteristics. The present invention relates to a stopped semiconductor device.

[0002]

2. Description of the Related Art Conventionally, electronic components such as diodes, transistors, and integrated circuits are mainly composed of an epoxy resin composition (hereinafter, referred to as an epoxy resin composition).
(Referred to as a resin composition). These resin compositions contain a halogen-based flame retardant and an antimony compound in order to impart flame retardancy. However, when a semiconductor device sealed with this resin composition is stored at a high temperature, the thermally decomposed halide is released from these flame retardant components, corroding the junction of the semiconductor element, and reducing the reliability of the device. It is known that the resin composition is damaged, and a resin composition capable of achieving a flame retardant grade V-0 without using a halogen-based flame retardant and an antimony compound as a flame retardant is required. As described above, the semiconductor device is operated under a high temperature (for example, 18
The corrosion resistance of the bonding portion (bonding pad portion) of the semiconductor element after storage at 5 ° C. or the like is called high-temperature storage characteristics. As a method for improving the high-temperature storage characteristics, diantimony pentoxide is used. Method (Japanese Patent Laid-Open No. 55-14695)
No. 0) and a method of combining antimony oxide and an organic phosphine (Japanese Patent Application Laid-Open No. 61-53321) have been studied and their effects have been confirmed. On the other hand, some types of resin compositions are not satisfactory. In addition, red phosphorus-based flame retardants are effective with a small amount of addition, and are useful for flame retardation of resin compositions.However, red phosphorus reacts with a small amount of water to produce phosphine and corrosive phosphoric acid. , There is a problem in the moisture resistance reliability. There is a need for a resin composition that is compatible with flame retardancy, high-temperature storage characteristics, and moisture resistance reliability and that does not use a halogen-based flame retardant or an antimony compound.

[0003]

SUMMARY OF THE INVENTION The present invention relates to an epoxy resin composition for semiconductor encapsulation which is excellent in moldability, flame retardancy, high-temperature storage characteristics, and humidity resistance, and for encapsulating a semiconductor element using the same. A semiconductor device is provided.

[0004]

The present invention provides (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator,
Semiconductor encapsulation characterized by comprising (D) an inorganic filler, (E) fused spherical silica coated with zinc molybdate, or talc coated with zinc molybdate, and (F) zinc borate as essential components. Epoxy resin composition for use and a semiconductor device obtained by sealing a semiconductor element using the same.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin used in the present invention refers to all monomers, oligomers and polymers having two or more epoxy groups in one molecule, and their molecular weight and molecular structure are not particularly limited. For example, biphenyl type epoxy resin, bisphenol type epoxy resin,
Stilbene epoxy resin, phenol novolak epoxy resin, cresol novolak epoxy resin, triphenolmethane epoxy resin, alkyl-modified triphenolmethane epoxy resin, epoxy resin containing triazine nucleus, dicyclopentadiene-modified phenol epoxy resin, biphenylene Novolak-type epoxy resins may be included, and these may be used alone or in combination.

The phenolic resin used in the present invention includes:
Monomers, oligomers and polymers generally having two or more phenolic hydroxyl groups in one molecule are not particularly limited in molecular weight and molecular structure. For example, phenol novolak resin, cresol novolak resin, dicyclopentadiene-modified phenol Resins, terpene-modified phenolic resins, triphenolmethane-type resins, novolak-type phenol resins containing biphenylene, and the like can be used, and these may be used alone or as a mixture.
Particularly, a phenol novolak resin, a dicyclopentadiene-modified phenol resin, a phenol aralkyl resin, a terpene-modified phenol resin and the like are preferable. The ratio of the number of epoxy groups of all epoxy resins to the number of phenolic hydroxyl groups of all phenol resins is 0.8 to 1.3.
Is preferred.

As the curing accelerator used in the present invention, any one can be used as long as it promotes a curing reaction between an epoxy group and a phenolic hydroxyl group, and those generally used for a sealing material can be used. For example, 1,8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, 2-methylimidazole, tetraphenylphosphonium / tetraphenylborate and the like can be mentioned, and these may be used alone or as a mixture. Absent.

As the inorganic filler used in the present invention, those generally used for a sealing material can be used. For example, fused silica powder, crystalline silica powder, talc, alumina, silicon nitride and the like can be mentioned, and these may be used alone or in combination. The amount of these components is preferably 60 to 95% by weight in the total resin composition in consideration of the balance between moldability and solder crack resistance, including the inorganic substance used as a core material of zinc molybdate described later. . If it is less than 60% by weight, the solder cracking resistance decreases with an increase in water absorption, and if it exceeds 95% by weight, problems such as wire sweep and pad shift are caused, which is not preferable.

The zinc molybdate used in the present invention acts as a flame retardant. Zinc molybdate has conventionally been known to be effective as a smoke suppressant and flame retardant for vinyl chloride resins, but has not been applied to semiconductor encapsulants. Regarding the flame retardant mechanism of zinc molybdate, it is known that zinc molybdate promotes the carbonization of the cured resin component during combustion, shuts off oxygen in the air, stops combustion, and reduces flame retardancy. It is expected to be achieved.

Although zinc molybdate may be used alone, it tends to absorb moisture easily, and if the amount is too large, the moisture absorption rate of the semiconductor device increases, and the moisture resistance reliability may decrease. Moldability decreases. Accordingly, inorganic materials, for example, transition metals, silica, alumina clay, talc, zinc oxide, calcium carbonate, aluminum nitride, silicon nitride, aluminum silicate, magnesium silicate, and other core materials coated with zinc molybdate are exemplified. But,
As the core material, fused spherical silica or talc is preferable in terms of ease of handling and cost. By coating the core material, only zinc molybdate on the surface acts as a flame retardant, and it is not necessary to mix a large amount of zinc molybdate, so that the increase in the moisture absorption rate can be suppressed and the moldability can be improved. it can.

The coating amount of zinc molybdate on fused spherical silica or talc is preferably 5 to 40% by weight. The average particle size of the fused spherical silica or talc coated with zinc molybdate is preferably 0.5 to 30 μm, and the maximum particle size is preferably 75 μm or less. The amount of zinc molybdate in the total resin composition is 0.05 to 5% by weight.
And more preferably 0.1 to 3% by weight.
If the content is less than 0.05% by weight, flame retardancy cannot be obtained. If the content exceeds 5% by weight, ionic impurities in the resin composition increase, and the moisture resistance reliability in a pressure cooker test or the like decreases, and the moldability also decreases. Is not preferred. The present invention obtained by coating fused spherical silica or talc with zinc molybdate can be obtained, for example, as follows. A slurry is prepared by mixing molybdenum oxide and fused spherical silica or talc in water, heated to 70 ° C., and a slurry of zinc oxide is slowly mixed with the slurry and stirred for about 1 hour. The solid is taken out by filtration, and after removing water at 110 ° C., it is pulverized. Thereafter, it is obtained by firing at 550 ° C. for 8 hours.

The zinc borate used in the present invention, like zinc molybdate, acts as a flame retardant. Zinc borate is 4ZnO.B ₂ O ₃ because of its balance between flame retardancy and humidity resistance.
· H ₂ O and _{2ZnO · 3B 2 O 3 · 3.5H} 2 O are preferred, in particular, ₂ O ₃ · 4ZnO · B from consideration of the moldability
H ₂ O is more preferred. The zinc borate of the present invention can be easily obtained from the market. The content of zinc borate is preferably 1 to 20% by weight, more preferably 1 to 5% by weight, based on the whole resin composition. If it is less than 1% by weight, the flame retardancy is insufficient, and if it exceeds 20% by weight, the moisture resistance reliability and the moldability are undesirably reduced.

Incidentally, zinc molybdate and zinc borate are
Each of them alone has flame retardancy, but when used in combination, the flame retardancy is further improved and the amount of addition can be reduced. The flame-retardant mechanism of zinc molybdate is to promote the carbonization of the cured resin component, and the flame-retardant mechanism of zinc borate is to release moisture and improve the strength of the carbonized layer. By using them in combination, the flame retardancy can be improved even if they are added in small amounts. In addition, both zinc molybdate and zinc borate also have a structure in which the curing accelerator is easily deactivated, so that the curability of the resin composition tends to decrease.However, by combining these flame retardants, Since a resin composition with a small amount is obtained, a decrease in curability can be minimized. In addition, since zinc molybdate is expensive, when used together with zinc borate, the amount of zinc molybdate used can be reduced, so that the cost can be reduced.

The ion scavenger used in the present invention reduces ionic impurities contained in resin components and the like by trapping halogen anions, organic acid anions and the like. These ionic impurities are known to corrode aluminum wirings and pads, but by using the ion scavenger of the present invention, it is possible to trap ionic impurities and prevent aluminum corrosion. it can. Examples of the ion scavenger of the present invention include Formulas (1) to (3), and these may be used alone or as a mixture. The compounding amount is preferably from 0.1 to 5% by weight in the whole resin composition. If the amount is less than 0.1% by weight, ionic impurities in the resin composition are insufficiently trapped, and the moisture resistance reliability in a pressure cooker test or the like is insufficient. If the amount exceeds 5% by weight, flame retardancy decreases, which is not preferable. . BiO _a (OH) _b (NO ₃ ) _c (1) (where a = 0.9 to 1.1, b = 0.6 to 0.8, c
= 0 to 0.4) BiO _a (OH) _b (NO ₃ ) _c (HSiO ₃ ) _d (2) (where a = 0.9 to 1.1, b = 0.6 to 0.8, c
+ D = 0.2 to 0.4) Mg _x Al _y (OH) _{2x + 3y-2z} (CO ₃ ) _z · mH ₂ O (3) (where 0 <y / x ≦ 1, 0 ≦ z / y <1.5, m is a positive number)

The resin composition of the present invention comprises the components (A) to (F) or the components (A) to (G) as essential components. And other additives such as a release agent such as natural wax and synthetic wax, and a low stress additive such as silicone oil and rubber. Further, the resin composition of the present invention comprises the components (A) to (F) or (A)
After sufficiently mixing the components (G) and other additives using a mixer or the like, the mixture is further melt-kneaded with a hot roll or a kneader, cooled, and pulverized. Using the resin composition of the present invention, to encapsulate various electronic components such as semiconductors, and to manufacture a semiconductor device, transfer molding, compression molding, injection molding and other conventional molding methods such as curing molding Good.

[0016]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to these examples. The mixing ratio is by weight. In addition, the epoxy resin used in the Examples and Comparative Examples,
The abbreviations and structures of the phenolic resins are summarized below. Epoxy resin (E-1): an epoxy resin having a structure represented by the formula (E-1) as a main component (epoxy equivalent 190 g /
eq)

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Epoxy resin (E-2): an epoxy resin represented by the formula (E-2) (epoxy equivalent: 210 g / eq)

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Phenol resin (H-1): Formula (H-1)
Phenolic resin (hydroxyl equivalent 175 g / e)
q)

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Phenol resin (H-2): Formula (H-2)
Phenolic resin (hydroxyl equivalent 104g / e)
q)

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Example 1 Epoxy resin (E-1) 85 parts by weight Phenol resin (H-1) 60 parts by weight 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) 2 parts by weight 740 parts by weight of fused spherical silica Flame retardant A (coated with 2 parts by weight of zinc molybdate per 8 parts by weight of fused spherical silica having an average particle size of 18 μm and a specific surface area of 2.0 m ² / g. Diameter 24 μm, Maximum particle size 74 μm.) 50 parts by weight Zinc borate (4ZnO.B ₂ O ₃ .H ₂ O) 50 parts by weight Epoxysilane coupling agent 5 parts by weight Carbon black 3 parts by weight Carnauba wax 5 parts by weight at room temperature Mix using a super mixer at 70 to 10
Roll kneading was performed at 0 ° C., followed by cooling and pulverization to obtain a resin composition. The obtained resin composition was evaluated by the following method. Table 1 shows the results.

Evaluation method Flame retardancy: 175 ° C. using a low pressure transfer molding machine
A test piece (127 mm × 1) was prepared at 70 kg / cm ² for 120 seconds.
(2.7 mm × 3.2 mm) and treated at 175 ° C. for 8 hours. Then, ΔF and Fmax were measured in accordance with the UL94 vertical method to determine the flame retardancy. Curability: Using a JSR Curastometer IVPS manufactured by Orientec Co., Ltd., the diameter of the die was 35 mm, the amplitude angle was 1 °, the molding temperature was 175 ° C., and the torque value after 90 seconds from the start of molding was measured. The unit is kgf · cm. High temperature storage characteristics: 17 using low pressure transfer molding machine
A 16 pDIP (chip size: 3.0 mm × 3.5 mm) was formed at 5 ° C., 70 kg / cm ² , 120 seconds, and 175
After 8 hours treatment at 185 ° C, 10 hours
00 hours), and the package in which the electric resistance between the wirings increased by 20% from the initial value was determined to be defective. The percentage defective in 15 packages was shown as a percentage. Units%.

Examples 2 to 9 and Comparative Examples 1 to 3 Resin compositions were prepared in the same manner as in Example 1 according to the formulations in Tables 1 and 2, and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2. In addition, the ion scavenger 1 of Example 4
Is BiO _1.0 (OH) _0.7 (NO ₃ ) _0.3 . The ion scavenger 2 of Example 5 was BiO _1.0 (OH) _0.7 (N
O ₃ ) _c (HSiO ₃ ) _d (where c + d = 0.3). In Example 6 and Comparative Example 1, DHT-4H (hydrotalcite-based compound) manufactured by Kyowa Chemical Industry Co., Ltd. was used as an ion scavenger. Flame retardant B of Example 8 was talc 7
It was coated with 3 parts by weight of zinc molybdate per part by weight (average particle size: 2.1 μm, maximum particle size: 10 μm).
In Comparative Example 1, a brominated bisphenol A type epoxy resin (epoxy equivalent: 365 g / eq.) Was used as a flame retardant.

[Table 1]

[0023]

[Table 2]

[0024]

According to the present invention, an epoxy resin composition for semiconductor encapsulation which does not contain halogen and antimony and has excellent moldability can be obtained.
Excellent in high temperature storage characteristics and humidity resistance reliability.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/36 C08K 3/36 3/38 3/38 9/02 9/02 H01L 23/29 H01L 23 / 30 R 23/31 F-term (reference) 4J002 CC03X CC04X CC05X CC07X CD00W CD03W CD05W CD06W CD07W CD13W DE147 DE289 DF039 DJ007 DJ009 DJ017 DJ018 DJ047 DJ048 DK009 EU096 EU116 EW016 EY016 FB078 FD017 FD018 AD03 FA01 DA03 FA01 DA03 FB07 JA07 4M109 AA01 BA01 CA21 EA02 EB03 EB04 EB06 EB08 EB09 EB12 EB13 EB17 EB19 EC01 EC14 EC20

Claims (4)

[Claims] 1. An epoxy resin, (B) a phenolic resin, (C) a curing accelerator, (D) an inorganic filler, (E) fused spherical silica coated with zinc molybdate, or zinc molybdate. An epoxy resin composition for encapsulating a semiconductor, comprising coated talc and (F) zinc borate as essential components. 2. Zinc borate is 4ZnO.B ₂ O ₃ .H ₂
2. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the composition is O. 3. The epoxy resin composition for semiconductor encapsulation according to claim 1, further comprising (G) an ion scavenger selected from the formulas (1), (2) and (3). An epoxy resin composition for semiconductor encapsulation, comprising: BiO _a (OH) _b (NO ₃ ) _c (1) (where a = 0.9 to 1.1, b = 0.6 to 0.8, c
= 0-0.4) BiO _a (OH) _b (NO ₃ ) _c (HSiO ₃ ) _d (2) (where a = 0.9-1.1, b = 0.6-0.8, c
+ D = 0.2 to 0.4) Mg _x Al _y (OH) _{2x + 3y-2z} (CO ₃ ) _z · mH ₂ O (3) (where 0 <y / x ≦ 1, 0 ≦ z / y <1.5, m is a positive number) 4. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1, 2 or 3.