JPH1121423A - Epoxy resin composition and semiconductor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition excellent in high-temperature storability without deteriorating flame retardance even if a halogen and an antimony compound are not contained and useful for sealing semiconductors by including zinc molybdate therein. SOLUTION: This composition is obtained by including (A) an epoxy resin such as a crystalline epoxy compound having two or more epoxy groups in one molecule (e.g. a compound represented by the formula), (B) a phenol resin curing agent having two or more phenolic hydroxyl groups in one molecule such as a phenolic novolak resin, (C) a curing accelerator such as 1,8- diazabicyclo[5.4.0]undecene-7, (D) an inorganic filler such as fused silica and (E) zinc molybdate. The component B is contained in an amount so as to provide preferably 0.8-1.3 ratio of the number of the epoxy groups in the component A to the number of the phenolic hydroxyl groups in the component B. The component D is contained in an amount of preferably 60-95 wt.% and the component E is contained in an amount of preferably 0.05-0.8 wt.%. The component E is preferably used in a state thereof applied onto the surface of an inorganic material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a halogen compound,
The present invention relates to an epoxy resin composition for semiconductor encapsulation which does not contain an antimony compound and has excellent high-temperature storage properties, and a semiconductor device using the same.

[0002]

2. Description of the Related Art Conventionally, electronic components such as diodes, transistors, and integrated circuits are mainly sealed with an epoxy resin composition. This epoxy resin composition (hereinafter, referred to as a resin composition) contains a halogen-based flame retardant as a flame retardant, or a combination of a halogen-based flame retardant and antimony trioxide. Gas is generated to achieve flame retardancy. However, these methods use a halogen compound or a combination system of a halogen compound and an antimony compound, so that while the electronic parts are exposed to high temperatures, corrosion of aluminum wiring by a halogen gas or an antimony halide gas or chip This causes a problem such as disconnection of the joint between the aluminum pad and the gold wire, which is a major problem. To solve such problems, use a resin composition such as a combination of epoxy resin and phenolic resin curing agent that has a higher glass transition temperature than the operating environment to reduce the diffusion of halogen gas and antimony halide gas during high-temperature storage. Method to improve high-temperature storage by adding an ion scavenger to trap halogen gas or antimony halide gas during high-temperature storage,
Further, a method combining these two types is used. However, in recent years, the surface mounting, miniaturization, and thinning of electronic components have been progressing, and the demand for improved solder resistance during mounting on circuit boards has become strict. Satisfaction is desired. However, even with a resin composition excellent in solder crack resistance containing a flame retardant system in which a halogen compound or a halogen compound and an antimony compound are used in combination, if the glass transition temperature is low, even if an ion scavenger is added, the high-temperature storability is low. On the other hand, a resin composition having a high glass transition temperature has insufficient solder crack resistance. For this reason, even if the glass transition temperature is low, an epoxy resin composition excellent in high-temperature storage property has not yet been provided.

[0003]

SUMMARY OF THE INVENTION The present invention is directed to an epoxy resin for semiconductor encapsulation which does not contain a halogen compound and an antimony compound without deteriorating flame retardancy and which has excellent high-temperature storage properties. A composition and a semiconductor device using the same are provided.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present invention has shown that by using zinc molybdate, long-term reliability at high temperatures can be achieved without reducing flame retardancy. The present inventors have found that an epoxy resin composition for semiconductor encapsulation that can significantly improve the properties can be obtained, and have completed the present invention. That is, the present invention provides (A) an epoxy resin,
(B) a phenolic resin curing agent, (C) a curing accelerator,
(D) An inorganic filler, and (E) a resin composition for semiconductor encapsulation containing zinc molybdate as an essential component. Particularly, as an epoxy resin, a crystalline epoxy compound represented by the formulas (1) to (3) is used. Optimal.

Embedded image (R in the formulas (1) to (3) represents a halogen atom or an alkyl group having 1 to 12 carbon atoms, and may be the same or different.)

[0005] Zinc molybdate used in the present invention acts as a flame retardant, and maintains the flame retardancy of a semiconductor device sealed with a resin composition containing the same, and significantly improves long-term reliability at high temperatures. . Although zinc molybdate may be used alone, it tends to absorb moisture, and when the amount is too large, the moisture absorption rate increases, and the solder crack resistance may decrease. Therefore, inorganic materials such as transition metals, silica, alumina clay, calcium carbonate, aluminum nitride, silicon nitride, aluminum silicate and magnesium silicate are coated with zinc molybdate so that only zinc molybdate on the surface acts as a flame retardant. By doing so, it is possible to suppress an increase in the moisture absorption rate due to an increase in the amount of zinc molybdate. The amount of zinc molybdate in the total resin composition is
0.05 to 0.8% by weight is preferred. Outside of this range, the amount of extracted impurities increases, and the reliability in environmental tests such as a pressure cooker test decreases. Examples of the substance coated with zinc molybdate include Sher.
It is commercially available from win Williams and the like.

The epoxy resin used in the present invention includes 1
Refers to all monomers, oligomers and polymers having two or more epoxy groups in the molecule, such as biphenyl type epoxy compounds, hydroquinone type epoxy compounds, stilbene type epoxy compounds, bisphenol type epoxy compounds, phenol novolak type epoxy resins, cresol novolak type Epoxy resins, triphenolmethane-type epoxy resins, alkyl-modified triphenolmethane-type epoxy resins, triazine nucleus-containing epoxy resins, dicyclopentadiene-modified phenol-type epoxy resins, and the like may be used alone or in combination. .
In the present invention, as in the resin composition using the crystalline epoxy compounds represented by the formulas (1) to (3), a low viscosity and a large amount of silica are blended, and the solder crack resistance is excellent, It is particularly effective for a resin composition having a low glass transition temperature of a product and having difficulty in storing at high temperatures.

The phenolic resin curing agent used in the present invention refers to all monomers, oligomers and polymers having two or more phenolic hydroxyl groups in one molecule.
Phenol novolak resin, cresol novolak resin, dicyclopentadiene-modified phenol resin, xylylene-modified phenol resin, terpene-modified phenol resin, triphenolmethane-type novolak resin, and the like may be used, and these may be used alone or in combination.
Particularly, a phenol novolak resin, a dicyclopentadiene-modified phenol resin, a xylylene-modified phenol resin, a terpene-modified phenol resin, and the like are preferable. The ratio of the number of epoxy groups in the epoxy resin to the number of phenolic hydroxyl groups in the phenol resin 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 the curing reaction between the epoxy group and the phenolic hydroxyl group, and those generally used for a sealing material can be widely used. For example, 1,8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, 2-methylimidazole, and the like,
These may be used alone or as a mixture.

As the inorganic filler used in the present invention, those generally used for a sealing material can be widely used, and examples thereof include fused silica powder, crystalline silica powder, alumina, and silicon nitride. These may be used alone or as a mixture. The blending amount is 60% in the total resin composition from the balance between moldability and solder crack resistance.
Preferably, it is contained in an amount of up to 95% by weight. If the amount is less than 60% by weight, the solder crack resistance is reduced due to an increase in the water absorption. If the amount exceeds 95% by weight, problems such as wire sweep and pad shift during molding are undesirable.

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. By using the ion trapping agent of the present invention, the ionic impurities are trapped and corrosion of aluminum is prevented. . Formulas (4) to (6) are given as examples of the ion scavenger, and these may be used alone or as a mixture. As the compounding amount,
It is preferably 0.1 to 5% by weight in the whole resin composition. 0.1
If the content is less than 5% by weight, the amount of extracted impurities is increased, and the reliability in environmental tests such as a pressure cooker test is insufficient. _{BiO a (OH) b (NO} 3) c (4) ( wherein, a = 0.9~1.1, b = 0.6~0.8 , c = 0~0.4) BiO a (OH ) _B (NO ₃ ) _c (HSiO ₃ ) _d (5) (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 (6) (where 0 <y / x ≦ 1, 0 ≦ z / y <1.5, and m is a positive number)

The resin composition of the present invention comprises the components (A) to (E) or the components (A) to (F) as essential components. In addition, if necessary, a silane coupling agent and carbon black may be used. And various additives such as a releasing 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 components (A) to (E),
Alternatively, after the components (A) to (F) and other additives are sufficiently and uniformly mixed using a mixer or the like, the mixture is further melt-kneaded with a hot roll or a kneader, cooled, and pulverized after cooling. These resin compositions can be applied to covering, insulating, sealing, and the like of transistors and integrated circuits, which are electric or electronic components.

[0012]

The present invention will be specifically described below with reference to examples. Example 1 The following composition. The mixing unit is parts by weight. Biphenyl type epoxy compound (YX4000K, manufactured by Yuka Shell Epoxy Co., Ltd .: melting point 105 ° C., epoxy equivalent 185 g / eq) 23.2 parts by weight Zinc molybdate 1.0 part by weight (3MgO · 4SiO ₂ is coated with zinc molybdate) The phenol novolak resin (softening point: 95 ° C., hydroxyl equivalent: 104 g / eq) 13.0 parts by weight 1,8-diazabicyclo (5,4,0) ) Undecene-7 (hereinafter referred to as DBU) 0.8 parts by weight Fused spherical silica powder (average particle size 15 μm) 696 parts by weight Carbon black 2.4 parts by weight Carnauba wax 2.4 parts by weight using a super mixer at room temperature And 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 tableted and evaluated by the following method. Table 1 shows the evaluation results.

Evaluation method Glass transition temperature: 1 using a low pressure transfer molding machine
A sample for measuring flame retardancy was molded under the conditions of 75 ° C., 70 kg / cm ² , and 120 seconds. Thereafter, post cure was performed at 175 ° C. for 8 hours. Sample size is 15mm x 6mm
× 3 mm. The measurement was performed using a thermomechanical analyzer to measure the thermal expansion of the test piece with the temperature rise, and the glass transition temperature was determined. Flame retardancy: 175 ° C using low pressure transfer molding machine
A sample for measuring flame retardancy was molded under the conditions of 70 kg / cm ² and 120 seconds. Thereafter, treatment was performed at 23 ° C. and 50% humidity for 48 hours. The sample size is 127 mm x 12.7
mm × 1.6 mm. The measuring method followed the UL94 vertical method. High temperature storage: 175 using low pressure transfer molding machine
3.0 ° C. under the conditions of 70 ° C., 70 kg / cm ² and 120 seconds.
A test chip element of × 3.2 mm was sealed in 16 pDIP. Thereafter, post cure was performed at 175 ° C. for 8 hours. The test semiconductor device was stored in an air atmosphere at 185 ° C., and the electrical resistance was measured at regular temperature at regular intervals. The total number of the test semiconductor devices was set to 10, and a device whose electric resistance value was twice as large as the initial value was regarded as a defect. Solder crack resistance: 0.1% at 175 ° C., 70 kg / cm ² , 120 seconds using a low pressure transfer molding machine.
A 9mm x 0.9mm test chip element is 80pQF
P sealed. Thereafter, post cure was performed at 175 ° C. for 8 hours. Processing at 85 ° C and 85% humidity, IR reflow 2
Surface cracks were observed at 40 ° C.

Examples 2 to 7 and Comparative Examples 1 and 2 Resin compositions were prepared in the same manner as in Example 1 according to the formulations shown in Table 1, and evaluated in the same manner as in Example 1. Table 1 shows the evaluation results. The epoxy resin of Example 4 used the hydroquinone type epoxy compound of the formula (7). The stilbene type epoxy compound of the formula (8) was used as the epoxy resin of Example 5. The ion scavenger 1 of Example 6 was obtained from BiO _a (OH) _b (N
O ₃ ) _c (HSiO ₃ ) _d (where a = 1, b = 0.7, c
+ D = 0.3). The ion scavenger 2 of Example 7 is DHT-4H (hydrotalcite-based compound) manufactured by Kyowa Chemical Industry Co., Ltd.

[0015]

Embedded image

[0016]

[Table 1]

[0017]

As described above, by encapsulating a semiconductor element with the resin composition of the present invention, a semiconductor device excellent in high-temperature storage property can be obtained.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08K 3/22 C08K 3/22 3/24 3/24 3/26 3/26 9/02 9/02 H01L 23/29 H01L 23/30 R 23/31

Claims (5)

[Claims] 1. An epoxy resin, (B) a phenol resin curing agent, (C) a curing accelerator, (D) an inorganic filler, and (E) zinc molybdate as essential components. Epoxy resin composition for semiconductor encapsulation. 2. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the zinc molybdate is coated with an inorganic material. 3. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the epoxy resin is a crystalline epoxy compound represented by formulas (1) to (3). Embedded image (R in the formulas (1) to (3) represents a halogen atom or an alkyl group having 1 to 12 carbon atoms, and may be the same or different.) 4. The semiconductor sealing epoxy resin composition according to claim 1, further comprising an ion scavenger represented by the formulas (4) to (6). Epoxy resin composition. _{BiO a (OH) b (NO} 3) c (4) ( wherein, a = 0.9~1.1, b = 0.6~0.8 , c = 0~0.4) BiO a (OH ) _B (NO ₃ ) _c (HSiO ₃ ) _d (5) (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 (6) (where 0 <y / x ≦ 1, 0 ≦ z / y <1.5, and m is a positive number) 5. A semiconductor device encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1, 2, 3, or 4.