JP2001049084A - Epoxy resin composition and semiconductor apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition for sealing a semiconductor, which is excellent in moldability, flame retardancy, a storage characteristic at a high temperature, the reliability of moisture resistance and a solder cracking property without containing a halogenic flame retardant or an antimony compound. SOLUTION: The epoxy resin composition comprises (A) an epoxy resin, (B) a phenolic resin, (C) a curing promotor, (D) an inorganic filler, (E) a metal hydroxide solid solution represented by formula I and (F) a zinc borate represented by formula II, as essential components. formula I: Mg1-xM2+x(OH)2. (M2+ is at least one divalent metallic ion selected from the group consisting of Mn2+, Fe2+, Co2+, Ni2+, Cu2+, and Z2+, and (x) is a number of 0.01<=x<=0.5). formula II: pZnO.qB2O3.rH2O. (each of (p), (q) and (r) is a positive number).

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, from the viewpoint of environment and hygiene, development of a resin composition having excellent flame retardancy without using a halogen-based flame retardant and an antimony compound has been demanded. 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. It is known that corrosion resistance is impaired and the reliability of semiconductor devices is impaired, and an epoxy 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. ing. As described above, the corrosion resistance of the bonding portion (bonding pad portion) of the semiconductor element after storing the semiconductor device at a high temperature (for example, 185 ° C.) is called a high-temperature storage characteristic, and the high-temperature storage characteristic is improved. A method using diantimony pentoxide (Japanese Unexamined Patent Application Publication No.
146950) and a method of combining antimony oxide with an organic phosphine (Japanese Unexamined Patent Publication No. 61-53321).
Patent Publication No. JP-A-2003-17753), and the effect has been confirmed, but some types of epoxy resin compositions are not satisfactory with respect to recent high levels of high-temperature storage characteristics required for semiconductor devices. In addition, zinc borate has been proposed as a flame retardant, and by adding a large amount thereof, a flame retardant grade V-0 can be achieved, and there is no problem in high-temperature storage characteristics. There is a problem that solder crack resistance is reduced. As a technique for improving the above-mentioned drawbacks, flame retardancy is achieved 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. There have been proposals to solve the problems of reliability and humidity resistance (JP-A-10-25148).
No. 6, JP-A-11-11945), in order to develop sufficient flame retardancy, a large amount of addition is required,
Therefore, there is a problem that the moldability and the solder crack resistance are deteriorated. 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, (E) a metal hydroxide solid solution represented by the general formula (1), and (F) zinc borate represented by the general formula (2) as essential components, and 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 kind of divalent metal ion selected from the group consisting of ²⁺ and Zn ²⁺ , and x represents a number of 0.01 ≦ x ≦ 0.5) pZnO · qB ₂ O ₃ · rH ₂ O (2) (where p, q, and r are positive numbers) More preferably, M ^{2+ of the} metal hydroxide solid solution represented by the general formula (1) is Zn ²⁺ or Ni ²⁺ , and zinc borate is 2Z
epoxy resin composition for semiconductor encapsulation, characterized in that nO · 3B is a ₂ O ₃ · 3.5H ₂ O, and a semiconductor device obtained by encapsulating 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, 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 powder, crystalline silica powder, talc, alumina, silicon nitride and the like can be mentioned, and these may be used alone or in combination. As the blending amount of the inorganic filler, the total amount of the metal hydroxide solid solution and zinc borate and the inorganic filler is 60 to 95% in the total epoxy resin composition from the balance of moldability and solder crack resistance. It is preferable that the content be contained by weight. 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 starts dehydration and absorbs heat during combustion. This inhibits the combustion reaction.
Further, it is known that carbonization of the cured resin component 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) is Mg _1-x M ²⁺ _x (OH) ₂ (1) (where M ²⁺ is Mn ²⁺ , Fe ²⁺ , Co ^{2 +} , Ni ²⁺ , Cu
²⁺ and Zn ^{2+ represent} at least one type of divalent metal ion, and x represents a number of 0.01 ≦ x ≦ 0.5.) This has the effect of improving performance. When the endothermic start temperature is low, moldability and reliability are adversely affected, and when the endothermic start temperature is higher than the decomposition temperature of the resin, the flame retardancy is reduced.However, the endothermic start temperature of the metal hydroxide solid solution used in the present invention is , Around 300 to 350 ° C. Of these, particularly preferred M ²⁺ is N ²⁺
i ²⁺ and Zn ²⁺ . The amount of the metal hydroxide solid solution represented by the general formula (1) is 1 to 1 in the total resin composition.
It is preferably 5% by weight, more preferably 1 to 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, and more preferably 0.5 to 30 μm.
5 to 10 μm.

The zinc borate represented by the general formula (2) used in the present invention acts as a flame retardant similarly to the metal hydroxide solid solution. Zinc borate represented by the general formula (2) is 2ZnO.3B ₂ O ₃ from the viewpoint of a balance between flame retardancy and moisture resistance reliability.
· 3.5 H ₂ O and _{4ZnO · B 2 O 3 · H} 2 O and the like, in _{particular, 2ZnO · 3B 2 O 3 ·} 3.5H 2 O exhibits a high flame retardancy. The compounding amount of zinc borate is preferably 1 to 20% by weight, more preferably 1 to 20% by weight in the whole resin composition.
10% by weight. If it is less than 1% by weight, the flame retardancy is insufficient,
If it exceeds 20% by weight, the moisture resistance reliability and the moldability are undesirably reduced. The average particle size is 1 to 30 μm, more preferably 5 to 20 μm.

The metal hydroxide solid solution and zinc borate each have the property of imparting flame retardancy even when used alone. However, a large amount of the compound is required to exhibit sufficient flame retardancy. When 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 combined use of the metal hydroxide solid solution and zinc borate further enhances the flame retardancy as a synergistic effect, and makes it possible to reduce the blending amount. Each of the flame retardants generates heat upon combustion, the metal hydroxide solid solution promotes the carbonization of the cured resin component, and zinc borate has the effect of improving the strength of the carbonized layer by forming a glassy film. Although the reason is not clear, the combined use of the two makes it possible to complement each other's abilities and obtain high flame retardancy as a synergistic effect. As a result, flame retardancy can be maintained even if the blending amount is reduced, and a decrease in moldability and strength, an increase in water absorption, and the like can be prevented.

The resin composition of the present invention comprises the components (A) to (F) as essential components, and optionally, a silane coupling agent, a coloring agent such as carbon black, a natural wax, and a synthetic wax. And various additives such as low-stress additives such as silicone oil and rubber. Further, the resin composition of the present invention,
After sufficiently mixing the components (A) to (F) and other additives and the like using a mixer or the like, the mixture is melt-kneaded with a hot roll or a kneader, cooled, and pulverized after cooling. 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.

[0013]

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)

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Phenol resin (H-1): Formula (H-1)
Phenolic resin (hydroxyl equivalent 165 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 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) 780 parts by weight of fused spherical silica Metal hydroxide solid solution (Mg _0.8 Zn _0.2 (OH) ₂ , average particle size 1 μm) 30 parts by weight zinc borate (2ZnO.3B ₂ O ₃ .3.5H ₂ O, average particle size 10 μm) 30 parts by weight Epoxy silane coupling agent 5 parts by weight Carbon black 3 parts by weight Carnauba wax 5 parts by weight at room temperature using a supermixer, 70 to 10 parts
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 Spiral flow: Measurement was performed 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: molding temperature 1 using low pressure transfer molding machine
A test piece (127 mm × 12.7 mm × 3.2 mm) was molded at 75 ° C., a pressure of 70 kg / cm ² and a curing time of 120 seconds, and after-baked at 175 ° C. for 8 hours, followed by the UL-94 vertical method. Measure F and Fmax,
The 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 as an after-bake at 175 ° C. for 8 hours. Later, 240
The flexural strength at ° C. was measured according to JIS K 6911. The unit is N / mm ² . Water absorption: molding temperature 1 using low pressure transfer molding machine
A test disk (diameter 50 mm, thickness 4 mm) was molded at 75 ° C., pressure 70 kg / cm ² , and curing time 120 seconds, and treated at 175 ° C. for 8 hours as an after-bake, then 150 ° C.
For 16 hours at 85 ° C. and a relative humidity of 85% for 168 hours, the percentage of increase in weight relative to the initial weight was determined. Units%. Solder crack resistance: Using low pressure transfer molding machine
Molding temperature 175 ° C, pressure 70kg / cm ² , curing time 1
In 20 seconds, 80 pQFP (2 mm thick, chip size 9.
0 mm × 9.0 mm), and after-baking at 175 ° C. for 8 hours, 85 ° C. and 85% relative humidity
96 hours of processing, and IR reflow processing (240
C., 10 seconds). Observe the processed package using an ultrasonic flaw detector and observe defects such as peeling and cracks inside the package. 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 percentage defective in 15 packages is shown as a percentage. Units%.

Examples 2 to 5 and Comparative Examples 1 to 5 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 results. The epoxy equivalent of the brominated bisphenol A type epoxy resin used in Comparative Example 1 was 365 g / eq. .

[Table 1]

[0020]

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 cracking.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 23/31 F-term (Reference) 4J002 CC032 CC042 CC052 CC072 CD001 CD031 CD041 CD051 CD061 CD071 CD141 CE002 DE078 DE098 DE108 DE118 DE147 DJ007 DJ017 DJ047 DK009 EU116 EU136 EW016 EW176 EY016 FD017 FD138 FD139 FD156 GQ05 4M109 AA01 BA01 CA21 EA02 EB03 EB04 EB07 EB12 EB18 EC01 EC03 EC14 EC20

Claims (4)

[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)
An epoxy resin composition for semiconductor encapsulation, comprising zinc borate represented by the general formula (2) as an essential component. 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 kind of divalent metal ion selected from the group consisting of ²⁺ and Zn ²⁺ , and x represents a number of 0.01 ≦ x ≦ 0.5) pZnO · qB ₂ O ₃ · rH ₂ O (2) (where p, q, and r are positive numbers) 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 method according to claim 1, wherein the zinc borate is 2ZnO.3B ₂ O _3.
3.5 H ₂ O in which claim 1 or 2 semiconductor encapsulating epoxy resin composition. 4. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1.