JP2001226564A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition for sealing a semiconductor which does not contain a halogen-containing flame-retardant and an antimonic compound and is excellent in molding properties, flame retardancy, high temperature storage characteristics, moisture resistance reliability and solder crack resistance. SOLUTION: The epoxy resin composition for sealing a semiconductor comprises, as essential components, (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator and (D) an inorganic filler, (E) a metal hydroxide solid solution represented by the formula: Mg1-xM2+x(OH)2 (wherein M2+ is at least one divalent metal ion selected from the group consisting of Mn2+, Fe2+, Co2+, Zn2+, Cu2+ and Ni2+; and (x) is a number of 0.01<=x<=0.5), and (F) a red phosphorus-based flame-retardant which is obtained by coating the surface of red phosphorus with aluminum hydroxide and further coating the surface thereof with a phenolic resin and has an average particle size of 0.1-70 μm and a maximum particle size of not larger than 200 μm.

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, and a semiconductor device.

[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. These epoxy resin compositions contain a halogen-based flame retardant and an antimony compound in order to impart flame retardancy. However, development of an epoxy resin composition having excellent flame retardancy without using a halogen-based flame retardant and an antimony compound is demanded from the viewpoint of environment and hygiene. Further, when a semiconductor device sealed with an epoxy resin composition containing a halogen-based flame retardant and an antimony compound is stored at a high temperature, a thermally decomposed halide is liberated from these flame retardant components and the semiconductor element is bonded. Is known to corrode the semiconductor device and impair the reliability of the semiconductor device.
There is a need for an epoxy resin composition that can achieve a flame retardant grade of UL94 V-0 without using a halogen-based flame retardant and an antimony compound as the flame retardant.

[0003] As described above, the corrosion resistance of the bonding portion (bonding pad portion) of a semiconductor element after storing a semiconductor device at a high temperature (for example, 185 ° C or the like) is called high-temperature storage characteristics. As a method for improving the characteristics, a method using diantimony pentoxide (Japanese Patent Laid-Open No.
146950) and a method of combining antimony oxide with an organic phosphine (Japanese Patent Application Laid-Open No. 61-53321) have been proposed and their effects have been confirmed. On the other hand, some types of epoxy resin compositions are not satisfactory. Also, a red phosphorus-based flame retardant has been proposed as a flame retardant. A flame retardant grade V-0 can be achieved by adding a large amount thereof, and there is no problem in high-temperature storage characteristics. Moisture resistance reliability, moldability,
There is a problem that solder crack resistance is reduced. As a technique for improving the above-mentioned disadvantages, by using a combination of a specific metal hydroxide and a specific metal oxide, or by using a composite metal hydroxide of a specific metal hydroxide and a specific metal oxide,
There have been proposals to solve the flame retardancy and the moisture resistance reliability (JP-A-10-251486, JP-A-11-1194).
No. 5), in order to exhibit sufficient flame retardancy, a large amount of addition is required, and therefore, there is a problem that the moldability and the solder crack resistance are reduced. That is, there is a need for an epoxy resin composition that maintains flame retardancy, is excellent in moldability, high-temperature storage characteristics, moisture resistance reliability, and solder crack resistance, and does not use a halogen-based flame retardant and an antimony compound.

[0004]

SUMMARY OF THE INVENTION The present invention is directed to a semiconductor encapsulation which does not contain a halogen-based flame retardant and an antimony compound and has excellent moldability, flame retardancy, high-temperature storage characteristics, moisture resistance reliability and solder crack resistance. An epoxy resin composition and a semiconductor device obtained by encapsulating a semiconductor element using the same are provided.

[0005]

The present invention provides (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator,
The surfaces of (D) an inorganic filler, (E) a metal hydroxide solid solution represented by the general formula (1), and (F) red phosphorus were coated with aluminum hydroxide, and the surfaces were further coated with a phenol resin. The average particle size is 0.1 to 70 μm
m, a red phosphorus-based flame retardant having a maximum particle size of 200 μm or less as an essential component, and Mg _1-x M ²⁺ _x (OH) ₂ (1) (where M ²⁺ is Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Zn ²⁺ , Cu
^Represents at least one type of divalent metal ion selected from the group consisting of ²⁺ and Ni ²⁺ , and x represents a number satisfying 0.01 ≦ x ≦ 0.5) More preferably, the general formula (1) M ²⁺ metal hydroxide solid solution is shown, a semiconductor device obtained by encapsulating a semiconductor element using Zn ^{2 +} or a semiconductor encapsulating epoxy resin composition is Ni ^2+, and the same.

[0006]

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, phenol aralkyl Type epoxy resin (having a phenylene skeleton, a diphenylene skeleton and the like) and the like, 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, phenol aralkyl resins (having a phenylene skeleton, diphenylene skeleton, and the like) and the like can be used alone or in combination. Of these, phenol novolak resins, dicyclopentadiene-modified phenol resins, phenol aralkyl resins, terpene-modified phenol resins, and the like are particularly preferable. The ratio of the number of epoxy groups in all epoxy resins to the number of phenolic hydroxyl groups in all phenolic resins is preferably 0.8 to 1.3.

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, crystalline silica, talc, alumina, silicon nitride and the like can be mentioned, and these may be used alone or in combination. As the compounding amount of the inorganic filler,
The total amount of the metal hydroxide solid solution, the red phosphorus-based flame retardant, and the inorganic filler is preferably 60 to 95% by weight in the total epoxy resin composition in view of the balance between moldability and solder crack resistance. preferable. 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 metal hydroxide solid solution represented by the general formula (1) used in the present invention acts as a flame retardant, and its flame retarding mechanism is such that the metal hydroxide solid solution starts dehydration and absorbs heat during combustion. This inhibits the combustion reaction. Further, it is known that carbonization of the cured resin is promoted, and it is considered that a flame retardant layer that blocks oxygen is formed on the surface of the cured product. Further, the metal hydroxide solid solution represented by the general formula (1) has an effect of appropriately lowering the endothermic start temperature and improving the flame retardancy. If the endothermic start temperature is low, the moldability and reliability are adversely affected, and if the endothermic start temperature is higher than the decomposition temperature of the cured resin, the flame retardancy is reduced, but the endothermic start of the metal hydroxide solid solution of the present invention is started. The temperature is an appropriate value around 300 to 350 ° C. Among them, particularly preferred M ²⁺ are Zn ²⁺ and Ni ²⁺ . The amount of the metal hydroxide solid solution represented by the general formula (1) is preferably 1 to 15% by weight, more preferably 1 to 15% by weight, based on the total epoxy resin composition.
-10% by weight. If it is less than 1% by weight, the flame retardancy is insufficient, and if it exceeds 15% by weight, the solder crack resistance and the moldability are undesirably reduced. The average particle size of the metal hydroxide solid solution represented by the general formula (1) is 0.5 to 30 μm.
m is preferred, and more preferably 0.5 to 10 μm.

The red phosphorus flame retardant used in the present invention is obtained by coating the surface of red phosphorus with aluminum hydroxide and further coating with a phenol resin. When red phosphorus is crushed into fine particles, the red phosphorus in the fractured surface has a very high activity and becomes unstable, and the moisture resistance tends to deteriorate. However, by coating with phenol resin after coating with aluminum hydroxide in advance, deterioration of moisture resistance can be prevented. Further, more preferred red phosphorus is fine particles made of red phosphorus or an aggregate thereof obtained by directly spheroidizing yellow phosphorus, and it is not necessary to use these particles by breaking them. The content of red phosphorus in the coated red phosphorus flame retardant is preferably 90 to 96% by weight. If the content of red phosphorus is less than 90% by weight, it is necessary to increase the amount added in the epoxy resin composition, and the moisture resistance deteriorates. on the other hand,
If it exceeds 96% by weight, there is a problem in the stability of red phosphorus.
The red phosphorus flame retardant preferably has an average particle size of 0.1 to 70 μm and a maximum particle size of 200 μm or less. The average particle size is 0.
If it is less than 1 μm, agglomeration or the like occurs, and if it exceeds 70 μm, dispersibility deteriorates. In order to improve the dispersibility, it is preferable that the maximum particle size is 200 μm or less, and if it exceeds 200 μm, the dispersibility deteriorates. The compounding amount of the red phosphorus-based flame retardant is preferably 0.2 to 2% by weight in the total epoxy resin composition.
If it is less than 0.2% by weight, the flame retardancy is insufficient, and if it exceeds 2% by weight, the moisture resistance is greatly reduced. As a red phosphorus flame retardant,
For example, there is Nova Excel manufactured by Rin Kagaku Kogyo Co., Ltd., which can be easily obtained from the market.

[0012] The metal hydroxide solid solution and the red phosphorus-based flame retardant are
Each of them has the property of imparting flame retardancy even if used alone, but a large amount of compounding is required to express sufficient flame retardancy. However, if it is blended in a large amount, the moldability and strength tend to decrease, and the water absorption tends to increase, and the solder crack resistance decreases. In order to prevent these physical properties from deteriorating, it is necessary to reduce the compounding amount as much as possible. The present inventor has found that by using a metal hydroxide solid solution and a red phosphorus-based flame retardant in combination, flame retardancy can be further improved as a synergistic effect and the blending amount can be reduced. The metal hydroxide solid solution has an endothermic effect at the time of combustion, further promotes carbonization of the cured resin, and red phosphorus has an effect of improving the strength of the carbonized layer by forming a polyphosphoric acid film. Although the reason is not clear, the combined use of both makes it possible to complement each other's abilities and obtain high flame retardancy as a synergistic effect. As a result, even if the blending amount is reduced, the flame retardancy is maintained, the moldability and the strength are reduced,
An increase in the water absorption can be prevented.

The epoxy resin composition of the present invention comprises (A)
The component (F) is an essential component, but if necessary, a silane coupling agent, a coloring agent such as carbon black, a release agent such as natural wax and synthetic wax, and a low stress such as silicone oil and rubber. Various additives such as additives may be appropriately compounded. In addition, the epoxy resin composition of the present invention is prepared by mixing the components (A) to (F) and other additives sufficiently and uniformly using a mixer or the like, and then melt-kneading with a hot roll or a kneader. , After cooling and pulverized. Various electronic components such as semiconductor elements are encapsulated using the epoxy resin composition of the present invention, and semiconductor devices are manufactured by curing and molding using conventional molding methods such as transfer molding, compression molding, and injection molding. do it.

[0014]

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 resin and the red phosphorus flame retardant 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)

Embedded image

Epoxy resin (E-2): an epoxy resin represented by the formula (E-2) (epoxy equivalent: 265 g / eq)

Embedded image

Phenol resin (H-1): Formula (H-1)
Phenolic resin (hydroxyl equivalent 165 g / e)
q)

Embedded image

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

Embedded image Red Phosphorus Flame Retardant 1: A surface of red phosphorus converted directly from yellow phosphorus into spheres, coated with aluminum hydroxide, and then further coated with a phenol resin.
% By weight, average particle size 20 μm, maximum particle size 51 μm. Red Phosphorus Flame Retardant 2: A substance obtained by coating the surface of ground red phosphorus with aluminum hydroxide and then further coating the surface with a phenol resin. The content of red phosphorus is 94% by weight, and the average particle size is 22 μm.
m, maximum particle size 50 μm.

Example 1 77 parts by weight of epoxy resin (E-1) 68 parts by weight of phenol resin (H-1) 2 parts by weight of 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) Fused spherical silica 805 parts by weight Metal hydroxide solid solution (Mg _0.8 Zn _0.2 (OH) ₂ , average particle size 1 μm) 30 parts by weight Red phosphorus-based flame retardant 1 5 parts by weight Epoxysilane coupling agent 5 parts by weight Carbon black 3 parts by weight 5 parts by weight of carnauba wax were mixed at room temperature using a super mixer,
Roll kneading was performed at 0 ° C., followed by cooling and pulverization to obtain an epoxy resin composition. The obtained epoxy resin composition was evaluated by the following method. Table 1 shows the results.

Evaluation method Spiral flow: Spiral flow was measured using a mold for measuring spiral flow according to EMMI-1-66 at a mold temperature of 175 ° C., a pressure of 70 kg / cm ² and a curing time of 120 seconds. 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 smaller the value, the slower the curing. The unit is kgf · cm. Flame retardancy: A test piece (127 mm × 12.7 mm × 3.2 mm) was molded using a low pressure transfer molding machine at a molding temperature of 175 ° C., a pressure of 70 kg / cm ² and a curing time of 120 seconds, and 175 ° C. as an after-bake. , After treatment for 8 hours, ΔF and Fmax were measured according to the UL-94 vertical method,
Flame retardancy was determined. Hot strength: A test piece (80 mm × 10 mm × 4 mm) was molded using a low pressure transfer molding machine at a molding temperature of 175 ° C., a pressure of 70 kg / cm ² and a curing time of 120 seconds, and treated at 175 ° C. for 8 hours as an after-bake. After that, 24
The flexural strength at 0 ° C. was measured according to JIS K 6911. The unit is N / mm ² . Water absorption: A test disk (diameter 50 mm, thickness 4 mm) was molded using a low-pressure transfer molding machine at a molding temperature of 175 ° C., a pressure of 70 kg / cm ² , and a curing time of 120 seconds. After that, 150
Dry at 16 ° C for 16 hours, 85 ° C, 85% relative humidity
168 hours, the percentage of increase in weight relative to the initial weight was determined. Units%. Solder crack resistance: 80 pQFP (2 mm thick, chip size 9.0 mm × 9.0 mm) was molded using a low pressure transfer molding machine at a molding temperature of 175 ° C., a pressure of 70 kg / cm ² , and a curing time of 120 seconds, followed by after-baking. After treatment at 175 ° C for 8 hours, 85 ° C and relative humidity of 8
96 hours processing at 5%, IR reflow processing (24
(0 ° C., 10 seconds). Using an ultrasonic flaw detector, defects such as peeling and cracks inside the package were observed. The number of defective packages in the six packages is shown. High-temperature storage characteristics: using a low-pressure transfer molding machine, molding temperature 175 ° C., pressure 70 kg / cm ² , curing time 120
16pDIP in seconds (chip size 3.0mm x 3.5m
m) was molded and treated as an after-bake at 175 ° C. for 8 hours, followed by a high-temperature storage test (185 ° C., 1000 hours)
The package in which the electric resistance between the wirings increased by 20% from the initial value was determined to be defective. The number of defective packages in the 15 packages is shown.

Examples 2 to 5 and Comparative Examples 1 to 5 According to the composition shown in Table 1, an epoxy resin composition was obtained in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 1 shows the results. Brominated bisphenol A used in Comparative Example 1
The epoxy equivalent of the epoxy resin is 365 g / eq. .

[Table 1]

[0021]

According to the present invention, an epoxy resin composition for encapsulating a semiconductor which does not contain a halogen-based flame retardant and an antimony compound and has excellent moldability can be obtained. Excellent high temperature storage characteristics, moisture resistance reliability and solder crack resistance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 23/29 H01L 23/30 R 23/31 F-term (Reference) 4J002 CC042 CC052 CC072 CD031 CD051 CD061 CD071 CD131 CD201 DA059 DE078 DE098 DE108 DE118 DE147 DJ007 DJ017 DJ047 EU116 EU136 EW146 EW176 FB079 FB269 FD017 FD138 FD139 FD142 FD156 4J036 AA01 FA01 FA02 FA04 FB07 4M109 AA01 EA02 EB07 EB12 EB18

Claims (5)

[Claims] 1. An epoxy resin, (B) a phenolic resin, (C) a curing accelerator, (D) an inorganic filler, (E) a metal hydroxide solid solution represented by the general formula (1), F)
After coating the surface of red phosphorus with aluminum hydroxide, the surface is further coated with a phenol resin, and a red phosphorus-based flame retardant having an average particle size of 0.1 to 70 μm and a maximum particle size of 200 μm or less is essential. An epoxy resin composition for encapsulating a semiconductor, comprising: a component. Mg _1-x M ²⁺ _x (OH) ₂ (1) (where M ²⁺ is Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Zn ²⁺ , Cu
^Represents at least one type of divalent metal ion selected from the group consisting of ²⁺ and Ni ²⁺ , and x represents a number satisfying 0.01 ≦ x ≦ 0.5) 2. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein M ^{2+ of the} metal hydroxide solid solution represented by the general formula (1) is Zn ²⁺ or Ni ²⁺ . 3. The epoxy resin composition according to claim 1, wherein the red phosphorus is red phosphorus or an aggregate thereof which is directly spheroidized upon conversion from yellow phosphorus. 4. The content of red phosphorus in the red phosphorus flame retardant is 90 to 90.
The epoxy resin composition according to claim 1, 2 or 3, which is 96% by weight. 5. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1.