JP3209664B2 - Resin composition for semiconductor encapsulation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly reliable resin composition for semiconductor encapsulation having excellent thermal conductivity.

[0002]

2. Description of the Related Art As a method for encapsulating semiconductor devices such as transistors, ICs and LSIs, a method by transfer molding of an epoxy resin composition has been adopted as a method suitable for mass production at low cost, and has been used up to the present day. On the other hand, semiconductor packages, particularly LSIs, are becoming more highly integrated, have more pins, operate at higher speeds, and generate more heat. Since the heat generated by this element hinders high speed operation, the conventional lead frame is made of copper,
Further, a copper heat radiating plate is attached to the package, and a die pad on which the Si chip is mounted is made thicker to radiate heat from the lower surface of the package. However, there have been problems of a complicated structure and an increase in cost. In addition, as a filler for the sealing resin composition, any one of crystalline silica, alumina, and silicon nitride, which have excellent thermal conductivity, is used as a main component to improve the heat dissipation of the package, but the heat dissipation is limited. Or there was a problem of mold wear.

[0003]

SUMMARY OF THE INVENTION The present invention provides a resin composition for semiconductor encapsulation for dramatically improving the heat dissipation of such semiconductor products.

[0004]

The present invention comprises an epoxy resin, a phenol resin curing agent, a curing accelerator, aluminum nitride and silica as essential components, and contains 80 to 96% by weight of aluminum nitride and silica in the total composition. And in a total of 100% by weight of aluminum nitride and silica,
(A) The average particle size is 10 to 30 μm and the maximum particle size is 200 μm
m to 30% by weight of aluminum nitride, (b)
2 to 10% by weight of spherical fine silica having an average particle size of 0.1 to 1.0 μm and a maximum particle size of 5 μm or less;
Spherical silica having a particle size of 30 μm and a maximum particle size of 74 μm or less
It is a resin composition for semiconductor encapsulation characterized by containing 8% by weight.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The epoxy resin used in the present invention is not particularly limited as long as it contains two or more epoxy groups. For example, cresol novolak type epoxy, trifunctional epoxy, biphenyl type epoxy, bisphenol type epoxy, brominated epoxy and the like can be mentioned. These epoxy resins may be used alone or as a mixture. The phenol resin curing agent is not particularly limited as long as it contains two or more hydroxyl groups. Examples include phenol novolak type, cresol novolak type, phenol aralkyl type, dicyclopentadiene type, and modified resins thereof. These phenol resins may be used alone or in combination. The amount of these curing agents is preferably such that the number of epoxy groups of the epoxy resin and the number of hydroxyl groups of the phenolic resin curing agent match. Examples of the curing accelerator include, but are not particularly limited to, imidazole, organic phosphine, tertiary amine, and 1,8-diazabicycloundecene. These may be used alone or as a mixture.

A feature of the present invention is that aluminum nitride (hereinafter referred to as ALN) is coated with an inorganic material composed of SiO _2, ALN having the characteristics of (a), spherical fine-grained silica having the characteristics of (b), and (c). This means that spherical silica having characteristics is optimally blended, whereby a highly reliable and highly thermally conductive resin composition with less mold wear can be obtained.
ALN and silica comprise 80-96% by weight in the total composition and in a total of 100% by weight of ALN and silica,
(A) The average particle size is 10 to 30 μm and the maximum particle size is 200 μm
m to 30% by weight of ALN, (b) 2 to 10% by weight of spherical fine silica having an average particle size of 0.1 to 1.0 μm and a maximum particle size of 5 μm or less, and (c) 10 to 30 μm of average particle size.
m, containing 3 to 68% by weight of spherical silica having a maximum particle size of 74 μm or less.

[0007] With ALN alone, the fluidity and filling property during molding,
Although there is a problem with burrs, a resin composition having excellent fluidity, filling properties, burrs, and high thermal conductivity can be obtained by setting the blending ratio of the present invention. ALN has an average particle size of 10 to 3
0 μm and the maximum particle size is 200 μm or less. If the average particle size is out of any of 10 to 30 μm, the fluidity and the burr are deteriorated. When the maximum grain size exceeds 200 μm, unfilling occurs due to gate clogging. Total 10 of ALN and silica
In 0% by weight, ALN contains 30 to 95% by weight, but if it is less than 30% by weight, sufficient thermal conductivity cannot be obtained, and if it exceeds 96% by weight, the fluidity is poor and unfilled, and burrs are poor. Become. Spherical fine silica is essential for deburring and improving fluidity, and has an average particle size of 0.1 to 1.0 μm and a maximum particle size of 5 μm or less. If the average particle size is not 0.1 to 1.0 μm, there is no effect on fluidity and burrs. If the maximum particle size exceeds 5 μm, there is no effect on fluidity and burrs. Furthermore, ALN and silica in total of 10
Although 0 to 10% by weight is contained in 0% by weight, excellent fluidity cannot be obtained if it is less than 2% by weight or exceeds 10% by weight. Spherical silica is essential for ensuring fluidity, and has an average particle size of l0 to
30 μm, maximum particle size 74 μm or less. Average particle size 1
If it is outside any of 0 to 30 μm, there is no improvement in fluidity. If the maximum particle size exceeds 74 μm, the filling property is undesirably reduced. In a total of 100% by weight of ALN and silica, 3
When the content is less than 3% by weight or more than 68% by weight, thermal conductivity and fluidity cannot be balanced. ALN
The mixing ratio between silica and silica is important, and proper moldability and sufficient thermal conductivity can be obtained within the scope of the present invention. Particle size and average particle size are measured using a laser-based particle size analyzer (Horiba, Ltd. LA-5)
00). ALN is coated with an inorganic material of SiO ₂ , and the weight change rate of the coated ALN is 1%.
It is required to be 5% by weight or less after the pressure cooker treatment at 25 ° C. and a relative humidity of 100% for 500 hours. If the content is not more than 5% by weight, the hydrolysis of ALN becomes large, and the molded product swells. By suppressing the hydrolysis resistance of the ALN itself, the moisture resistance reliability of the semiconductor element can be guaranteed. This inorganic-coated ALN is produced by Dow Chemical, Toyo Aluminum Co., Ltd. and can be easily obtained from the market.

The coefficient of thermal expansion of the resin composition for encapsulating a semiconductor of the present invention must be 2.0 × 10 ⁻⁵ 1 / ° C. or lower at a glass transition temperature or lower. If it exceeds 2.0 × 10 ⁻⁵ 1 / ° C., the temperature cycle resistance deteriorates especially in LSI applications. Further, the thermal conductivity of the resin composition needs to be 1.25 W / m ° C. or more. If it is less than this, the heat dissipation property of the LSI particularly deteriorates. The present invention comprises an epoxy resin, a phenolic resin curing agent, a curing accelerator, ALN and silica as essential components. In addition to these, a filler surface treating agent such as a silane coupling agent, a brominated epoxy resin, Flame retardants such as antimony oxide, coloring agents such as carbon black and red iron oxide, release agents such as natural wax and synthetic wax, and low stress additives such as silicone oil and rubber, and other various additives may be appropriately compounded. . Further, in order to produce the resin composition for semiconductor encapsulation of the present invention as a molding material,
Epoxy resin, phenolic resin curing agent, curing accelerator, A
After sufficiently mixing LN, silica, and other additives uniformly using a mixer or the like, the mixture is melt-kneaded with a hot roll or a kneader or the like, and then cooled and pulverized to obtain a sealing material.

Hereinafter, the present invention will be described by way of examples. The mixing ratio is shown in parts by weight. Example 1 90 parts by weight of a biphenyl type epoxy resin (manufactured by Yuka Shell Co., Ltd., YX4000H, epoxy equivalent 190, melting point 170 ° C.) 90 parts by weight brominated epoxy resin (manufactured by Dainippon Ink and Chemicals, Epicron 152) Epoxy equivalent 360, softening point 65 ° C) 8 parts by weight phenol novolak resin (manufactured by Sumitomo Durez Co., Ltd., hydroxyl equivalent 105, softening point 70 ° C) 52 parts by weight Surface-coated ALN (Dow Chemical, XU, average) Particle size 25 μm, maximum particle size 130 μm, surface coated with SiO ₂ ) 750 parts by weight Spherical fine silica (average particle size 0.5 μm, maximum particle size 3 μm) 20 parts by weight Spherical silica (average particle size 23 μm, maximum particle size) 74 μm) 200 parts by weight γ-glycidoxypropyltrimethoxysilane (Nippon Unicar Co., Ltd.) 6 parts by weight 2-methylimidazole (Shikoku Chemicals) 1 part by weight Antimony trioxide 8 parts by weight Hoechst wax E 3 parts by weight Carbon plaque 2 parts by weight is sufficiently mixed at room temperature, then kneaded at 80 to 110 ° C. using a biaxial heat roll and cooled. Thereafter, the resultant was pulverized to obtain a resin composition for semiconductor encapsulation.

The obtained resin composition for encapsulating a semiconductor is heated at a temperature of 175 ° C. and an injection pressure of 120 K using a transfer molding machine.
A test piece was obtained by molding at g / cm ² , and the following items were evaluated. Evaluation method Spiral flow: Measured at 175 ° C. and an injection pressure of 70 kg / cm ² using a mold conforming to EMII-I-66. The unit is cm. Gel time: Measured on a hot plate at 175 ° C. The unit is seconds. Thermal conductivity: Measured at room temperature using a probe-type thermal conductivity measuring instrument (manufactured by Showa Denko KK) on a molded product of 50 mm x 50 mm.
The unit is W / m ° C. Filling property: The filling property of a thin QFP having a package size of 28 × 28 × 1.4 mm and a chip size of 14 × 14 × 0.3 mm was evaluated based on a void generation rate, a die pad shift defective rate, and a wire flow defective rate. Mold abrasion: Evaluated by the weight loss rate (%) of the aluminum orifice when 500 g of the resin composition for semiconductor encapsulation was passed at 175 ° C. through the aluminum orifice based on the SEMI method. Moisture resistance reliability: 8 at 300 mil SOP using simulated device
After moisture absorption at 5 ° C. and 85% RH for 72 hours, a soldering treatment at 260 ° C. was performed for 10 seconds, and then a pressure cooker treatment at 125 ° C. and a relative humidity of 100% was performed for 500 hours. Table 1 shows the evaluation results. Thermal expansion coefficient is 15 × 4 × 4m
m test piece at 175 ° C, post-curing at 175 ° C for 8 hours, and then TMA (Seiko
Co., Ltd.) at 60 ° C. The unit is × 10
^-5 1 / ° C.

Examples 2 to 4 A resin composition for encapsulating a semiconductor was obtained in the same manner as in Example 1 with the composition shown in Table 1. The cresol novolak type epoxy resin used in Example 3 had an epoxy equivalent of 200 and a softening point of 6.
Orthocresol novolak epoxy resin at 5 ° C. The phenol aralkyl resin used in Examples 2 to 4 and Comparative Example 3 was manufactured by Mitsui Toatsu Chemicals, Inc., XL-225-3.
L. Table 1 shows the evaluation results. Comparative Examples 1 to 5 A resin composition for encapsulating a semiconductor was obtained in the same manner as in Example 1 with the composition shown in Table 2. ALN (without surface coating) used in Comparative Example 5 was manufactured by Dow Chemical Co. and had an average particle size of 25 μm and a maximum particle size of 130 μm. Table 2 shows the evaluation results.

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

By using the resin composition of the present invention, abrasion of a molding die can be reduced, and heat dissipation of a semiconductor product can be greatly improved.

Continuation of the front page (51) Int.Cl. ⁷ identification symbol FI // H01L 23/29 H01L 23/30 R 23/31 (58) Field surveyed (Int.Cl. ⁷ , DB name) C08L 63/00- 63/10 C08K 3/36 C08K 3/28 C08K 9/02 C08G 59/62 H01L 23/29

Claims (2)

(57) [Claims] An epoxy resin, a phenol resin curing agent,
A curing accelerator, aluminum nitride and silica as essential components, aluminum nitride is coated with SiO ₂ , and
The coated aluminum nitride has a temperature of 125 ° C. and a relative humidity of 100.
%, Weight change after 500 hours of pressure cooker treatment
Conversion ratio is 5% by weight or less, aluminum nitride and silica are contained in the entire composition in an amount of 80 to 96% by weight, and in a total of 100% by weight of aluminum nitride and silica, (a) an average particle size of 10 to 30 μm; 30 to 95% by weight of aluminum nitride having a maximum particle diameter of 200 μm or less, (b) 2 to 10% by weight of spherical micro silica having an average particle diameter of 0.1 to 1.0 μm and 5 μm or less, (c) average Particle size 10-30μ
m. A resin composition for encapsulating a semiconductor, comprising 3 to 68% by weight of spherical silica having a maximum particle size of 74 μm or less. 2. The resin composition for semiconductor encapsulation according to claim 1, which has a thermal expansion coefficient and a thermal conductivity of 2.0 × 10 ^-5 1 / ° C. or less and 1.25 W / m or less at a glass transition temperature or less, respectively. A resin composition for encapsulating a semiconductor having a temperature of at least ℃.