JP2002212397A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition which is used for sealing semiconductors, does not contain a halogenated flame retardant and an antimony compound, and has excellent moldability, flame retardancy, high temperature storage characteristics and soldering crack resistance. SOLUTION: This epoxy resin composition for sealing semiconductors, containing (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator, (D) an inorganic filler, and (E) aluminum hydroxide as essential components, is characterized in that the content of Na2O contained in the aluminum hydroxide is <=0.1 wt.%.

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 usually 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. And it is known that the reliability of the semiconductor device is impaired. Even if a halogen-based flame retardant and an antimony compound are not used as the flame retardant, the flame retardant grade is UL-94 V-.
There is a demand for an epoxy resin composition that can achieve zero.
As described above, the semiconductor device is heated at a high temperature (for example, 185 ° C.).
Etc.), the corrosion resistance of the bonding portion (bonding pad portion) of the semiconductor element after storage is called high-temperature storage characteristics. As a method for improving the high-temperature storage characteristics, a method using diantimony pentoxide ( Japanese Patent Application Laid-Open No. 55-146950) 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. Some types of epoxy resin compositions are unsatisfactory for high required levels of properties. Conventionally,
A method of adding aluminum hydroxide as a flame retardant has been proposed. By adding a large amount of aluminum hydroxide, flame retardancy can be maintained and high-temperature storage characteristics can be improved. However, there has been a problem that the decomposition starting temperature is low, and dehydration decomposition is started at the temperature at the time of the soldering treatment, thereby lowering the solder crack resistance. That is,
There is a need for an epoxy resin composition that maintains flame retardancy, is excellent in solder crack resistance, and does not use a halogen-based flame retardant and an antimony compound.

[0003]

SUMMARY 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 moldability, flame retardancy, high-temperature storage properties, and solder crack resistance. An object and a semiconductor device obtained by sealing a semiconductor element using the same are provided.

[0004]

Means for Solving the Problems The present invention provides [1] (A)
An epoxy resin, (B) a phenol resin, (C) a curing accelerator, (D) an inorganic filler, and (E) aluminum hydroxide as essential components, and Na ₂ contained in aluminum hydroxide.
An epoxy resin composition for encapsulating a semiconductor, characterized in that O is 0.1% by weight or less, [2] The temperature at which the weight reduction rate of aluminum hydroxide reaches 10% is 270 ° C or more. ] The epoxy resin composition for semiconductor encapsulation according to the above item,
[3] The epoxy resin composition for semiconductor encapsulation according to [1] or [2], wherein the average particle size of the aluminum hydroxide is 1 to 30 μm, and the maximum particle size is 75 μm or less.
[4] The first [1], [2], wherein the total amount of the aluminum hydroxide contained in the epoxy resin composition is 1 to 20% by weight, and each of the bromine atom and the antimony atom is less than 0.01% by weight. Or a semiconductor element is encapsulated with the epoxy resin composition for semiconductor encapsulation according to the item [3], or the epoxy resin composition for semiconductor encapsulation according to any one of the items [1] to [4]. 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 type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, triphenolmethane type epoxy resin, alkyl-modified triphenolmethane type epoxy resin, naphthol type epoxy resin, epoxy resin containing triazine nucleus, dicyclopentadiene modified phenol type Epoxy resins, phenol aralkyl type epoxy resins (having a phenylene skeleton, biphenylene skeleton, etc.) and the like, and these may be used alone or
More than one kind may be used 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, biphenylene skeleton, etc.), and naphthol aralkyl resins (having a phenylene skeleton, biphenylene skeleton, etc.). More than one kind may be used in combination. Of these, phenol novolak resins,
Preferred are dicyclopentadiene-modified phenolic resins, phenol aralkyl resins, naphthol aralkyl resins, terpene-modified phenol resins, and the like. The compounding amount of the epoxy resin and the phenol resin is preferably 0.8 to 1.3 in the ratio of the number of epoxy groups of all epoxy resins to the number of phenolic hydroxyl groups of all phenol resins.

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 can be used alone or in combination of two or more kinds. No problem.

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 of two or more. In particular, fused silica is preferred. The content of the inorganic filler is preferably from 60 to 95% by weight, more preferably from 70 to 95% by weight in the total epoxy resin composition, from the balance between moldability and solder crack resistance.
90% by weight. If it is less than 60% by weight, the solder cracking resistance will be reduced due to an increase in water absorption, and if it exceeds 95% by weight, problems such as wire sweep and pad shift may occur.

The aluminum hydroxide used in the present invention is flame-retardant
It acts as an agent, and its flame retardant mechanism is
Aluminum chloride starts dehydrating and decomposing and absorbs heat.
This inhibits the combustion reaction. Also, hardened trees
It is known to promote carbonization of fat components,
It is considered that a flame-retardant layer that blocks oxygen is formed on the surface. This
Temperature of decomposition of aluminum hydroxide at 300 ° C
It is near, but Na _TwoContamination of impurities such as O
Is one of the factors that lower the decomposition onset temperature
Become. This Na_TwoO in the production process of aluminum hydroxide
Although it is mixed, Na_TwoHydroxide with reduced O
Use of aluminum suppresses a decrease in decomposition start temperature
Can be controlled. Contained in the aluminum hydroxide of the present invention.
Na_TwoThe amount of O is 0.1% by weight or less.
Is preferred. If it exceeds 0.1% by weight, the decomposition start temperature
Degree, the solder cracking resistance decreases.
Absent.

The decomposition start temperature of aluminum hydroxide is preferably 270 ° C. or more at a temperature at which the weight loss rate reaches 10%. If the temperature is 270 ° C. or lower, dehydration decomposition starts at the temperature at the time of the solder processing, and the solder crack resistance may be reduced. The temperature at which the weight loss rate of the aluminum hydroxide in the present invention reaches 10% is determined by weighing 10 mg of aluminum hydroxide and using a differential thermal / thermogravimetric analyzer (TG / DTA-220, manufactured by Seiko Denshi Kogyo KK).
Was measured at a temperature rising rate of 10 ° C./min. The average particle size of the aluminum hydroxide is preferably 1 to 30 μm, more preferably 1 to 15 μm. The maximum particle size is preferably 75 μm or less. When the average particle size is 1 μm or less, a large amount of Na ₂ O tends to be easily taken in, and when the average particle size is 30 μm or more, the specific surface area becomes small and the flame retardancy may be insufficient. The content of aluminum hydroxide is preferably from 1 to 20% by weight, more preferably from 1 to 15% by weight, based on the whole epoxy resin composition.
If it is less than 1% by weight, flame retardancy is insufficient, and if it exceeds 20% by weight, moldability such as fluidity and curability, and solder crack resistance may be reduced.

The total amount of the aluminum hydroxide 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. 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, there is a possibility that problems such as wire sweep and pad shift may occur.

The epoxy resin composition of the present invention comprises (A)
In addition to the component (E), a flame retardant such as a brominated epoxy resin or antimony oxide may be contained as necessary, but the semiconductor device must have stable electrical characteristics at a high temperature of 150 to 200 ° C. In such applications, the content of bromine atoms and antimony atoms is preferably less than 0.01% by weight in the total epoxy resin composition, and more preferably not completely contained. If either the bromine atom or the antimony atom is 0.01% by weight or more, the resistance value of the semiconductor device increases with time when left at a high temperature, and eventually the gold wire of the semiconductor element breaks. Can occur. Also, from the viewpoint of environmental protection, the content of each of bromine atoms and antimony atoms is less than 0.01% by weight,
It is desirable that they are not contained as much as possible.

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.

[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 abbreviation and structure of the phenol resin and the contents of aluminum hydroxide are shown below. Epoxy resin (E-1): an epoxy resin having a structure represented by the formula (E-1) as a main component (epoxy equivalent 190)

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

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Phenol resin (H-1): Formula (H-1)
Phenolic resin (hydroxyl equivalent 165)

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Phenol resin (H-2): Formula (H-2)
Phenolic resin (hydroxyl equivalent 104)

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Aluminum hydroxide 1: The temperature at which the Na ₂ O content is 0.07% by weight and the weight reduction rate reaches 10% is 2%.
Aluminum hydroxide having an average particle diameter of 10 μm and a maximum particle diameter of 50 μm at 80 ° C. Aluminum hydroxide 2: Na ₂ O content of 0.03 wt%, temperature of 285 ° C. to a weight reduction rate reaches 10%, an average particle diameter of 4 [mu] m, maximum particle diameter 20μm aluminum hydroxide. Aluminum hydroxide 3: Na ₂ O content 0.3% by weight,
Aluminum hydroxide having a temperature at which the weight loss reaches 10% at 255 ° C., an average particle size of 3 μm, and a maximum particle size of 20 μm. Aluminum hydroxide 4: Na ₂ O content 0.5% by weight,
Aluminum hydroxide having a temperature at which the weight loss rate reaches 10% at 250 ° C., an average particle size of 0.8 μm, and a maximum particle size of 15 μm.

Example 1 78 parts by weight of epoxy resin (E-1) 67 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 790 parts by weight Aluminum hydroxide 1 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 using a mixer, roll kneading at 70-100 ° C, After cooling, the mixture was pulverized 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 6.9 MPa and a curing time of 120 seconds. The unit is cm. 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 higher the value, the faster the curing. The unit is N · m. 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 6.9 MPa, and a curing time of 120 seconds. After the treatment for 8 hours, the flame retardancy was determined according to the UL-94 vertical method. 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 6.9 MPa, and a curing time of 120 seconds, and treated at 175 ° C. for 8 hours as an after-bake. After, 240 ° C
Was measured in accordance with JIS K 6911. The unit is N / mm ² . Water absorption: A 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 6.9 MPa, and a curing time of 120 seconds, and treated at 175 ° C. for 8 hours as an after-bake. Then, at 150 ° C, 16
Drying time is 168 at 85 ° C and 85% relative humidity.
The percentage of the increase in weight relative to the initial weight was determined for those subjected to the time treatment. Units%. Solder crack resistance: Using a low-pressure transfer molding machine, molding temperature 175 ° C, pressure 6.9 MPa, curing time 1
In 20 seconds, 80pQFP (thickness 2 mm, chip size 9.0 mm × 9.0 mm) was formed, and after-baked at 175 ° C. for 8 hours, 85 ° C. and relative humidity 8
96 hours processing at 5%, IR reflow processing (26
(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, a molding temperature of 175 ° C., a pressure of 6.9 MPa, and a curing time of 120 seconds, 16 pDIP (chip size: 3.0 mm × 3.5 m)
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)
Was performed, 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 is shown as a percentage. Units%. Content of bromine atom and antimony atom: Compression molded to a diameter of 40 mm and a thickness of 5 to 7 mm at a pressure of 5.9 MPa, and the obtained molded product was subjected to X-ray fluorescence spectroscopy to obtain bromine atoms in all epoxy resin compositions. And the content of antimony atoms were quantified. The unit is% by weight.

Examples 2 to 6 and Comparative Examples 1 to 4 An epoxy resin composition was obtained in the same manner as in Example 1 according to the composition 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 Example 6 and Comparative Example 1 is 365.

[Table 1]

[0022]

According to the present invention, an epoxy resin composition for semiconductor encapsulation which does not contain a halogen-based flame retardant and an antimony compound and has excellent moldability such as fluidity and curability can be obtained.
A semiconductor device using this is excellent in flame retardancy, high-temperature storage characteristics, and solder crack resistance.

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Claims (5)

[Claims] 1. An epoxy resin, (B) a phenolic resin, (C) a curing accelerator, (D) an inorganic filler, and (E) aluminum hydroxide as essential components. An epoxy resin composition for semiconductor encapsulation, wherein ₂ O is 0.1% by weight or less. 2. The weight loss rate of aluminum hydroxide is 10
%. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the temperature to reach% is 270 ° C. or more. 3. The aluminum hydroxide has an average particle size of 1 to 3.
The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the epoxy resin composition has a particle size of 0 μm and a maximum particle size of 75 μm or less. 4. The method according to claim 1, wherein the total amount of the aluminum hydroxide contained in the total epoxy resin composition is 1 to 20% by weight, and each of the bromine atom and the antimony atom is less than 0.01% by weight. 4. The epoxy resin composition for semiconductor encapsulation according to 3. 5. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1.