JP2001226561A - 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 antimony 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 ingredients, (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator, (D) an inorganic filler and (E) a metal hydroxide solid solution represented by the general formula: Mg1-xM2+x(OH)2 (wherein M2+ is at least one divalent metal ion selected from the group consisting of Mn2+, Fe2+, Co2+, Ni2+, Cu2+ and Zn2+; and (x) is a number of 0.01<=x<=0.5), and the specific surface area of the metal hydroxide solid solution represented by the general formula is 1.5-4.5 m2/g.

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 released from these flame retardant components, and the semiconductor device is bonded. (Bonding pad portion) is known to corrode and impair the reliability of the semiconductor device, and the flame retardant grade is U even if a halogen-based flame retardant and an antimony compound are not used as the flame retardant.
An epoxy resin composition capable of achieving V-0 with L94 is required. As described above, the corrosion resistance of the junction of the semiconductor elements after the semiconductor device is stored at a high temperature (for example, 185 ° C.) is referred to as high-temperature storage characteristics. As a method for improving the high-temperature storage characteristics, A method using diantimony pentoxide (JP-A-55-146950) and a method of combining antimony oxide with an organic phosphine (JP-A-61-53321) have been proposed and their effects have been confirmed. However, some types of epoxy resin compositions are not satisfactory with respect to recent high levels of high-temperature storage characteristics required for semiconductor devices. Further, zinc borate has been proposed as a flame retardant other than the above, and when added in a large amount, a flame retardant grade of UL94 can achieve V-0, and there is no problem with high-temperature storage characteristics. There is a problem that reliability, moldability, and solder crack resistance deteriorate. Furthermore, as a technology that has improved the above disadvantages,
Solves flame retardancy and moisture resistance reliability by using a combination of a specific metal hydroxide and a specific metal oxide, or using a composite metal hydroxide of a specific metal hydroxide and a specific metal oxide Although proposals have been made (JP-A-10-251486, JP-A-11-11945, etc.), a large amount of addition is required in order to develop sufficient flame retardancy. There is a problem that causes deterioration of cracking property. 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.

[0003]

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.

[0004]

The present invention provides (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator,
(D) an inorganic filler and (E) a metal hydroxide solid solution represented by the general formula (1) as essential components, and (E) a specific surface area of the metal hydroxide solid solution represented by the general formula (1) is 1.
5 to 4.5 m ² / g; Mg _1−x M ²⁺ _x (OH) ₂ (1) (where M ²⁺ is Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu
^Represents at least one type of divalent metal ion selected from the group consisting of ²⁺ and Zn ²⁺ , and x represents a number satisfying 0.01 ≦ x ≦ 0.5) More preferably, in general formula (1) The epoxy resin composition for semiconductor encapsulation, wherein M ^{2+ of the} metal hydroxide solid solution shown is Zn ²⁺ or Ni ²⁺ , and a semiconductor element is encapsulated using the same. A semiconductor device characterized by the following.

[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, 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. 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 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,
In the total amount of the metal hydroxide solid solution and the inorganic filler,
From the balance between moldability and solder crack resistance, 60 to 95% by weight in the total epoxy resin composition is 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. Its flame retarding mechanism is that the metal hydroxide solid solution starts dehydration and absorbs heat during combustion. This inhibits the combustion reaction. Further, it is known that the metal contained in the metal hydroxide solid solution used in the present invention promotes the carbonization of the resin component during combustion, and when the cured product burns, forms a carbonized layer of the resin component on the surface. It is believed that the layer acts as a flame retardant layer that blocks oxygen. Further, the metal hydroxide solid solution of the present invention has an effect of appropriately lowering the endothermic onset 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 resin component, the flame retardancy decreases, but the endothermic start temperature of the metal hydroxide solid solution of the present invention is reduced. Is an appropriate value around 300 to 350 ° C. Of these, particularly preferred M ²⁺ is N ²⁺
i ²⁺ and Zn ²⁺ . The compounding amount of the metal hydroxide solid solution of the present invention is preferably 1 to 25% by weight, more preferably 1 to 10% by weight, based on the whole epoxy resin composition.
If it is less than 1% by weight, the flame retardancy is insufficient, and if it exceeds 25% by weight, the water absorption increases, so that the solder crack resistance is reduced, or the curing of the resin is inhibited, and the moldability and the strength of the cured product are reduced. It is not preferable. The specific surface area of the metal hydroxide solid solution of the present invention is preferably from 1.5 to 4.5 m ² / g. If it is less than 1.5 m ² / g, the efficiency of the expression of the flame retardancy becomes poor, and it is necessary to increase the addition amount, which is not preferable.
If it exceeds 4.5 m ² / g, it is not preferable because the fluidity is reduced and the curability and the strength of the cured product are reduced. The average particle diameter of the metal hydroxide solid solution of the present invention is 0.5 to 3
It is preferably 0 μm, more preferably 0.5 to 10 μm.

The epoxy resin composition of the present invention comprises (A)
The component (E) 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. Further, the epoxy resin composition of the present invention is obtained by sufficiently mixing the components (A) to (E) and other additives uniformly using a mixer or the like, and then melt-kneading the mixture 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.

[0011]

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: 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 Metal hydroxide solid solution 1: Mg _0.8 Zn _0.2 (OH) ₂ , specific surface area 2.0 m ² / g, average particle size 1.5 μm Metal hydroxide solid solution 2: Mg _0.8 Zn _0.2 (OH) ₂ , specific surface area 4 0.1 m ² / g, average particle size 0.9 μm metal hydroxide solid solution 3: Mg _0.8 Zn _0.2 (OH) ₂ , specific surface area 0.9 m ² / g, average particle size 3.2 μm metal hydroxide solid solution 4: Mg _0.8 Zn _0.2 (OH) ₂ , specific surface area 6.3 m ² / g, average particle diameter 0.6 μm

Example 1 Epoxy resin (E-1) 6.0 parts by weight Phenol resin (H-1) 5.5 parts by weight 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) 0.2 parts by weight Fused spherical silica 77.0 parts by weight Metal hydroxide solid solution 1 10.0 parts by weight Epoxysilane coupling agent 0.5 parts by weight Carbon black 0.3 parts by weight Carnauba wax 0.5 parts by weight Mix at room temperature using a supermixer, 70-10
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 as a percentage. Units%. High-temperature storage characteristics: using a low-pressure transfer molding machine, molding temperature 175 ° C., pressure 70 kg / cm ² , curing time 12
16pDIP in 0 seconds (chip size 3.0mm × 3.5
mm), and after-baked at 175 ° C. for 8 hours, subjected to a high-temperature storage test (185 ° C., 1000 hours).
The increased package was determined to be defective. The percentage defective in the 15 packages is shown as a percentage. Units%.

Examples 2 to 4 and Comparative Examples 1 to 6 According to the formulations 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. The epoxy equivalent of the brominated bisphenol A type epoxy resin used in Comparative Examples 1 and 2 was 365 g / e.
q. .

[Table 1]

[0018]

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.

Continued on the front page F-term (reference) 4J002 CC032 CC072 CD031 CD041 CD051 CD052 CD061 CD062 CD071 CD131 DE077 DE097 DE107 DE117 DE146 DJ006 DJ016 DJ046 EQ018 EU118 EW138 EW178 EX000 EY018 FD016 FD090 FD137 FD142 FD158 FD160 G01 EA160 G03 EB12 EB18 EC01 EC03 EC14 EC20

Claims (3)

[Claims] An essential component is (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator, (D) an inorganic filler, and (E) a metal hydroxide solid solution represented by the general formula (1). (E) The epoxy resin composition for semiconductor encapsulation, wherein (E) the specific surface area of the metal hydroxide solid solution represented by the general formula (1) is from 1.5 to 4.5 m ² / g. Mg _1-x M ²⁺ _x (OH) ₂ (1) (where M ²⁺ is Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu
^Represents at least one type of divalent metal ion selected from the group consisting of ²⁺ and Zn 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. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1.