JP2857441B2 - Sealing resin composition and semiconductor sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention has a small coefficient of thermal expansion, a large thermal conductivity,
The present invention relates to an epoxy-based encapsulating resin composition having excellent moisture resistance and moldability, and having a well-balanced property, and a semiconductor encapsulating device sealed with a cured product thereof.

(Prior Art) Conventionally, a method of sealing electronic components such as diodes, transistors, and integrated circuits using a thermosetting resin has been performed. This resin sealing is economically advantageous as compared with the hermetic sealing method using glass, metal, and ceramic, and is therefore widely used. As a sealing resin, an epoxy resin is most commonly used among thermosetting resins in terms of reliability and cost. Epoxy resins include
Curing agents such as acid anhydrides, aromatic amines, and novolak phenol resins are used. Among them, epoxy resin using novolak type phenol resin as curing agent is superior in moldability and moisture resistance, non-toxic, and inexpensive compared to those using other curing agents, so it is a resin for semiconductor encapsulation. Widely used as. As the filler, fused silica powder or crystalline silica powder is most commonly used together with the above-mentioned curing agent. 2. Description of the Related Art In recent years, with the increase in density and power consumption of semiconductor components, there has been a demand for a resin for semiconductor encapsulation with more heat dissipation.

(Problems to be Solved by the Invention) However, a resin composition comprising an epoxy resin using a novolak-type phenol resin as a curing agent and a fused silica powder has a small coefficient of thermal expansion, good moisture resistance, and bonding by a hot-cold cycle test. Although it has the characteristics of being excellent in wire opening, resin cracks, pellet cracks, and the like, it has a drawback that power semiconductors have poor heat dissipation due to low thermal conductivity and large power consumption, so that their functions cannot be performed. On the other hand, a resin composition comprising an epoxy resin using a novolak-type phenol resin as a curing agent and crystalline silica powder has a high thermal conductivity when the proportion of the crystalline silica powder is increased, and also has a good heat dissipation. However, there are disadvantages that the coefficient of thermal expansion is large and the reliability with respect to moisture resistance is deteriorated. Furthermore, the sealed product obtained from this resin composition has a drawback that the mechanical properties and moldability are reduced. Therefore, there is naturally a limit in increasing the thermal conductivity of the sealing resin composition using silica powder.

The present invention has been made to solve the above-mentioned drawbacks, and has excellent thermal conductivity, moisture resistance, moldability, a small coefficient of thermal expansion, good heat dissipation, a low elastic modulus, a good balance of properties, and reliability. It is an object of the present invention to provide a sealing resin composition and a semiconductor sealing device having high properties.

[Constitution of the Invention] (Means for Solving the Problems) The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have obtained a surface treatment with a methyl methacrylate / butadiene / styrene copolymer resin and a specific silazane compound. It has been found that the above object can be achieved by blending the silicon nitride powder, and the present invention has been completed.

That is, the present invention provides (A) an epoxy resin, (B) a novolak-type phenol resin, (C) a methyl methacrylate-butadiene-styrene copolymer resin, and (D) a silazane compound R ₃ Si-NH having the following general formula: -SiR ₃ (wherein R is an alkyl group or a phenyl group) and the surface-treated average particle size 10~50μm nitride-containing silicon powder as essential components, nitriding of the the resin composition (D) A sealing resin composition containing 25 to 90% by weight of silicon powder, and a semiconductor sealing device in which a semiconductor pellet is sealed with a cured product thereof.

The epoxy resin (A) used in the present invention is not particularly limited in molecular structure, molecular weight and the like as long as it is a compound having at least two epoxy groups in its molecule, and widely includes commonly used resins. Can be. For example, bisphenol-type aromatic resins, alicyclic resins such as cyclohexane derivatives, and epoxy novolak-based epoxy resins represented by the following general formulas are exemplified.

(In the formula, R ¹ represents a hydrogen atom, a halogen atom or an alkyl group, R ² represents a hydrogen atom or an alkyl group, and n represents an integer of 1 or more.) These epoxy resins may be used alone or in combination of two or more. Used.

As the novolak type phenol resin (B) used in the present invention, a novolak type phenol resin obtained by reacting phenols such as phenol and alkylphenol with formaldehyde or paraformaldehyde, and modified resins thereof, for example, epoxidized or butylated novolak type Phenol resins and the like are used, and these are used alone or in combination of two or more. The mixing ratio of the novolak type phenolic resin is determined by the molar ratio of the epoxy group (a) of the epoxy resin (A) to the phenolic hydroxyl group (b) of the novolak type phenolic resin [(a) / (b)].
Is desirably in the range of 0.1 to 10. 0.1 molar ratio
If it is less than 10 or more than 10, the moisture resistance, the molding workability and the electrical properties of the cured product will be poor, and any case is not preferred.

The (C) methyl methacrylate / butadiene / styrene copolymer resin used in the present invention may be any copolymer of methyl methacrylate, butadiene and styrene, and is not limited to the composition ratio of each monomer.
The mixing ratio of the methyl methacrylate / butadiene / styrene copolymer resin is 0.1 to 10% by weight based on the resin composition.
Is desirable. If the proportion is less than 0.1% by weight, the effect of lowering the elasticity is not obtained, and if it exceeds 10% by weight, the moldability is poor, which is not preferable. Preferably 1.0 to 5.0
% By weight. The method of compounding the methyl methacrylate / butadiene / styrene copolymer resin is not particularly limited, but is preferably dispersed uniformly in a novolak-type phenol resin.

The silicon nitride powder (D) having an average particle size of 10 to 50 μm used in the present invention is a surface treated with a silazane compound having the following general formula.

R ₃ Si—NH—SiR ₃ (where R represents an alkyl group or a phenyl group) This is obtained by pulverizing silicon nitride while supplying a silazane compound quantitatively and adjusting the particle size. Examples of the silicon nitride used here include a trigonal type (α-Si ₃ N ₄ ) and a hexagonal type (β-Si ₃ N ₄ ), and these can be used alone or in combination of two or more. Further, specific examples of the silazane compound include hexamethylsilazane, tetramethyldiphenylsilazane, and the like, and these can be used alone or in combination of two or more. The amount used for the surface treatment is not particularly limited, but may be any amount as long as the surface layer of the silicon nitride powder is treated into a monomolecular layer. The surface-treated silicon nitride powder has a 150 mesh pass, and preferably has an average particle size of 10 to 50 μm.
If the average particle size is less than 10 μm or more than 50 μm, fluidity,
A problem arises in the workability, and in particular, if the coarse particle diameter is 104 μm or more, the wire flows during molding and the gate is clogged, and the flowability is impaired, which is not preferable. By treating the surface of the silicon nitride with a silazane compound, the surface of the silicon nitride is made water-repellent to prevent hydrolysis of the silicon nitride and enhance compatibility with the matrix resin. The compounding ratio of the silicon nitride powder is 25 to 90% by weight based on the resin composition. If the proportion is less than 25% by weight, the coefficient of thermal expansion is large and the thermal conductivity is small, which is not preferable. On the other hand, if it exceeds 90% by weight, bulkiness is large and moldability is poor, which is not suitable for practical use and is not preferred.

The encapsulating resin composition of the present invention contains an epoxy resin, a novolak type phenol resin, a methyl methacrylate / butadiene / styrene copolymer resin, and a silicon nitride powder surface-treated with a silazane compound as essential components. To the extent not contrary to the above, and if necessary, release agents such as natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, paraffins, chlorinated paraffins, bromotoluene, hexa Flame retardants such as bromobenzene and antimony trioxide, carbon black,
A coloring agent such as redwood, various curing agents, and the like can be appropriately added and blended.

A general method for preparing the encapsulating resin composition of the present invention as a molding material includes epoxy resin, novolak type phenol resin, methyl methacrylate / butadiene / styrene copolymer resin, and silicon nitride surface-treated with a silazane compound. After mixing the powder and other raw materials in a predetermined composition ratio sufficiently uniformly using a material mixer, etc., further perform a melt mixing process using a hot roll, or a mixing process using a kneader, etc., then solidify by cooling, and pulverize to an appropriate size. To form a molding material. If the molding material thus obtained is applied to sealing, coating, insulating and the like of electronic components such as semiconductor devices or electronic components, excellent characteristics and reliability can be imparted.

The semiconductor encapsulation device of the present invention can be easily manufactured by encapsulating a semiconductor pellet using the above-described encapsulation resin composition. The semiconductor pellet to be sealed is not particularly limited, for example, with an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, and the like. The most common sealing method is a low-pressure transfer molding method, but sealing by injection molding, compression molding, casting or the like is also possible. After molding, the sealing resin composition is further heated and thermoset, and finally a semiconductor encapsulation device sealed with a cured product of the composition is obtained. The post-curing by heating is desirably performed by heating at 150 ° C. or higher.

(Examples) The present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples. In Examples and Comparative Examples, “%” means “% by weight”.

Example 1 Cresol novolak epoxy resin (epoxy equivalent 21
5) Silicon nitride powder treated with 8% of novolak type phenol resin (phenol equivalent: 107) and hexamethylsilazane at 16% (average particle size of 150 mesh cut 30 μm) 71.
5%, 2% of methyl methacrylate / butadiene / styrene copolymer resin and 2.5% of release agent etc. are mixed at room temperature,
The mixture was further kneaded at 90 to 95 ° C and cooled and pulverized to produce a molding material.

Example 2 In Example 1, instead of 71.5% of silicon nitride powder treated with hexamethylsilazane, 31.5% of silicon nitride powder treated with hexamethylsilazane (average particle size of 150 mesh cut 30 μm) and crystalline silica powder ( Average particle size 38
(m) A molding material was produced in the same manner as in Example 1 except that a 40% mixed system was used.

Comparative Example 1 Cresol novolak epoxy resin (epoxy equivalent 21
5) Novolak type phenol resin (phenol equivalent 107) 8%, methyl methacrylate butadiene
Styrene copolymer resin 2.0%, fused silica powder surface-treated with hexamethylsilazane 71.5%, other release agents 2.5
% In the same manner as in Example 1 to produce a molding material.

Comparative Example 2 A molding material was produced in the same manner as in Comparative Example 1 except that crystalline silica powder (average particle size: 28 μm) was used instead of the fused silica powder surface-treated with hexamethylsilazane.

Comparative Example 3 Cresol novolak epoxy resin (epoxy equivalent 21
5) Novolak type phenol resin (phenol equivalent: 107) 9%, silicon nitride powder (average particle size of 60 mesh pass: 60 μm) 70%, and other 3% were added to 18%, and a molding material was prepared in the same manner as in Comparative Example 1 by adding 3%. Manufactured.

Semiconductor pellets were sealed using the molding materials manufactured in Examples 1 and 2 and Comparative Examples 1 to 3, and were heated and cured at 170 ° C. to manufacture a semiconductor sealing device. Various tests were performed on the molding material and the semiconductor sealing device, and the results are shown in Table 1. The present invention has good thermal properties, and is excellent in moisture resistance and moldability, confirming the effects of the present invention.

[Effects of the Invention] As is clear from the above description and Table 1, the sealing resin composition and the semiconductor sealing device of the present invention have thermal characteristics,
It is excellent in moisture resistance and moldability, has a low elastic modulus, has a good balance of these properties, and has high reliability.

Continuation of the front page (51) Int.Cl. ⁶ identification code FI H01L 23/31 // (C08K 9/06 3:34 5:54) (56) References JP-A-3-43444 (JP, A) JP-A-63-225617 (JP, A) JP-A-3-205444 (JP, A) JP-A-1-240556 (JP, A) JP-A-62-74924 (JP, A) JP-A-64-90253 (JP, A) JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 63/00-63/10 C08L 55/00 C08G 59/62 C08K 9/06 C08K 3/34 C08K 5/54 H01L 23 / 29

Claims (2)

(57) [Claims] 1. An epoxy resin, (B) a novolak type phenol resin, (C) a methyl methacrylate / butadiene / styrene copolymer resin, and (D) a silazane compound R ₃ Si—NH— having the following general formula: A silicon nitride powder having an average particle diameter of 10 to 50 μm surface-treated with SiR ₃ (wherein R represents an alkyl group or a phenyl group) as an essential component; , 25 to 90% by weight of the resin composition for sealing. 2. An epoxy resin, (B) a novolak type phenol resin, (C) a methyl methacrylate / butadiene / styrene copolymer resin, and (D) a silazane compound R ₃ Si—NH— having the following general formula: A silicon nitride powder having an average particle diameter of 10 to 50 μm surface-treated with SiR ₃ (wherein R represents an alkyl group or a phenyl group) as an essential component; Semiconductor sealing device, wherein a semiconductor pellet is sealed with a cured product of a sealing resin composition containing 25 to 90% by weight.