JP2857444B2 - 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 relates to a sealing resin composition excellent in moisture resistance, solder heat resistance and moldability, and a semiconductor sealing device.

(Prior Art) In recent years, at the same time as the development of high integration and high reliability technologies in the field of semiconductors and integrated circuits, automation of a semiconductor device mounting process has been promoted. For example, when attaching a flat package type semiconductor device to a circuit board, soldering has conventionally been performed for each lead pin, but recently, the entire semiconductor device has been immersed in a solder bath heated to 250 ° C and soldered all at once. Is performed.

A conventional semiconductor device encapsulated with a resin composition comprising an epoxy resin, a novolak-type phenol resin and an inorganic filler has a drawback that when the entire device is immersed in a solder bath, the moisture resistance is reduced. In particular, when a semiconductor device that has absorbed moisture is immersed in a solder bath, peeling occurs between the sealing resin and the semiconductor chip or between the sealing resin and the frame, causing significant moisture resistance deterioration, disconnection due to electrode corrosion, and leakage due to moisture. There is a disadvantage that current is generated and long-term reliability cannot be guaranteed. For this reason, there has been a strong demand for the development of an encapsulating resin that has little influence on moisture resistance and has good moldability with little moisture resistance deterioration even when the entire semiconductor device is immersed in a solder bath.

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned drawbacks and to meet the demand, and has a small influence of moisture absorption, and particularly has excellent moisture resistance and solder heat resistance after immersion in a solder bath. An object of the present invention is to provide a sealing resin composition having good moldability and a semiconductor sealing device.

[Constitution of the Invention] (Means for Solving the Problems) As a result of intensive studies to achieve the above object, the present inventor has found that by adding a phosphazene-based fluororubber, moisture resistance after immersion in a solder bath and Improved solder heat resistance,
In addition, they found that the moldability was improved, and completed the present invention. That is, the present invention provides (A) an epoxy resin, (B) a novolak-type phenol resin, and (C) a phosphazene-based fluororubber represented by the following general formula: (Where R ¹ is C _p H _2p C _q F _{2q + 1} and R ² is C _t H _2t C _s F
_{2s + 1} , l, m, n, p, q, s, and t represent an integer of 1 or more.) (D) Inorganic filler is an essential component, and the phosphazene-based resin (C) is used for the resin composition. A sealing resin composition comprising 0.1 to 5% by weight of a fluororubber and 25 to 90% by weight of the inorganic filler (D), and a cured product of the sealing resin composition. Wherein the semiconductor pellet is sealed.

 Hereinafter, the present invention will be described in detail.

The epoxy resin (A) used in the present invention is not particularly limited in molecular structure, molecular weight, etc., as long as it is a compound having at least two epoxy groups in its molecule. Can be widely encompassed. Examples thereof include bisphenol-type aromatic resins, aliphatic resins such as cyclohexane derivatives, and epoxy novolak resins represented by the following general formula.

(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.

Novolak-type phenol resins (B) used in the present invention include novolak-type phenol resins 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 these resins are used alone or in combination of two or more. The mixing ratio of the novolak type phenol resin is the equivalent ratio of the epoxy group (a) of the epoxy resin and the phenolic hydroxyl group (b) of the novolak type phenol resin [(a) /
(B)] is preferably in the range of 0.1 to 10. If the equivalent ratio is less than 0.1 or exceeds 10, the moisture resistance, the molding workability and the electrical properties of the cured product are deteriorated, and any case is not preferred. Therefore, it is better to limit to the above range.

As the (C) phosphazene-based fluororubber used in the present invention, for example, those represented by the above general formula are used. As the phosphazene-based fluororubber, for example, a long-chain rubber (PNCl ₂ ) obtained by thermally decomposing a trimer of dichlorophosphonitrile
Is reacted with a fluorinated alcohol. Specific compounds include the following.

These can be used alone or in combination of two or more. The phosphazene-based fluororubber is desirably contained in an amount of 0.1 to 5% by weight based on the entire resin composition. If this ratio is less than 0.1% by weight, there is no effect on solder heat resistance, and if it exceeds 5% by weight, the resin viscosity increases.
This has an adverse effect on moldability and is not suitable for practical use and is not preferred.

As the inorganic filler (D) used in the present invention, silica powder, alumina, antimony trioxide, talc, calcium carbonate, titanium white, clay, mica, red iron oxide,
Glass fibers and the like can be mentioned, and these can be used alone or in combination of two or more. Among these, silica powder and alumina powder are particularly preferable and are often used. The mixing ratio of the inorganic filler is 25 to 90% by weight based on the whole resin composition. If the proportion is less than 25% by weight, moisture resistance, solder heat resistance, mechanical properties and moldability deteriorate, and if it exceeds 90% by weight, burrs increase and moldability deteriorates, which is not suitable for practical use.

The encapsulating resin composition of the present invention contains an epoxy resin, a novolak-type phenol resin, a phosphazene-based fluororubber, and an inorganic filler as essential components, as long as the object of the present invention is not impaired, and if necessary, natural. Waxes,
Release agents such as synthetic waxes, metal salts of linear fatty acids, acid amides, esters, and paraffins; flame retardants such as chlorinated paraffins, brominated toluene, hexabromobenzene, and antimony trioxide; carbon black; , A silane coupling agent, various curing accelerators, and the like can be appropriately added and blended.

A general method for producing the encapsulating resin composition of the present invention as a molding material is an epoxy resin, a novolak-type phenol resin, a phosphazene-based fluororubber, an inorganic filler, and other raw material components in a predetermined composition ratio. After selecting and mixing sufficiently uniformly by a mixer, etc., further perform a melt mixing process with a hot roll, or a mixing process with a kneader, etc.
Next, it is cooled and solidified, and pulverized to an appropriate size to obtain a molding material. Then, this molding material can be applied to sealing of electronic parts or electric parts, and their coating, insulation and the like, so that excellent characteristics and reliability can be imparted.

The semiconductor sealing device of the present invention can be easily manufactured by sealing a semiconductor pellet using the sealing resin composition obtained as described above. 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. The sealing resin composition is cured by heating at the time of sealing,
Finally, a semiconductor sealing device sealed with a cured product of the composition is obtained. Curing by heating is desirably performed by heating at a temperature of 150 ° C. or higher. 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.

(Function) In the present invention, desired properties can be obtained by using a phosphazene-based fluororubber.
The phosphazene-based fluororubber improves the adhesion between the sealing resin composition and the semiconductor pellet, and the adhesion between the sealing resin composition and the lead frame, and reduces the moisture resistance even when immersed in a solder bath. Can be reduced.

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

Example 1 Cresol novolak epoxy resin (epoxy equivalent 21
5) Novolak type phenol resin (phenol equivalent: 107) 9% to 18%, next phosphazene-based fluoro rubber 0.3%, 71% of fused silica powder, 0.3% of ester-based wax and 0.4% of silane-based coupling agent were blended, mixed at room temperature, kneaded and cooled at 90 to 95 ° C, and then pulverized to produce a molding material. This molding material was transferred into a mold heated to 170 ° C. and cured to form a molded product (sealed product). The molded article was tested for properties such as moisture resistance, and the results are shown in Table 1. In particular, a remarkable effect of the present invention was recognized on moisture resistance.

Examples 2-3 Cresol novolak epoxy resin (epoxy equivalent 21
5) To 19%, 9% of novolak type phenol resin (phenol equivalent 107), the following phosphazene-based fluoro rubber, 0.3% in Example 2, 0.3% in Example 3, silica powder 71
%, Ester wax 0.3% and silane coupling agent 0.4% were blended, kneaded and pulverized in the same manner as in Example 1 to produce a molding material. In addition, a molded product was prepared and a characteristic test such as moisture resistance was performed in the same manner as in Example 1. The results are shown in Table 1. The remarkable effect of the present invention on the moisture resistance was recognized.

Comparative Example Cresol novolak epoxy resin (epoxy equivalent 21
5) 19%, 9% of novolak type phenol resin (phenol equivalent 107), silica powder 71%, curing accelerator 0.3%, ester wax 0.3% and silane coupling agent
0.4% was blended, and a molding material was produced in the same manner as in Example 1. A molded article was formed using this molding material, and a test was performed on various characteristics of the molded article in the same manner as in Example 1. The results are shown in Table 1.

[Effects of the Invention] As is clear from the above description and Table 1, the sealing resin composition of the present invention has a good adhesion to a semiconductor chip and a lead frame, so that it is less affected by moisture absorption and has a small effect on a solder bath. It is excellent in moisture resistance even after immersion in the electrode. As a result, disconnection due to electrode corrosion and occurrence of leak current due to moisture can be significantly reduced, and reliability can be guaranteed for a long time. In addition, it exhibited excellent solder heat resistance despite immersion in a solder bath at 250 ° C.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ identification symbol FI // (C08L 63/00 85:02) (58) Investigated field (Int.Cl. ⁶ , DB name) C08L 63/00- 63/10 C08L 85/02 C08G 59/62 H01L 23/29

Claims (2)

(57) [Claims] 1. An epoxy resin (B) a novolak type phenolic resin (C) a phosphazene-based fluororubber represented by the following general formula: (Where R ¹ is C _p H _2p C _q F _{2q + 1} and R ² is C _t H _2t C _s F
_{2s + 1} , l, m, n, p, q, s, and t represent an integer of 1 or more. (D) Inorganic filler is an essential component, and the phosphazene-based fluoro rubber of (C) is used with respect to the resin composition. 0.1 to 5% by weight, and 25 to 90% by weight of the inorganic filler (D). (A) an epoxy resin; (B) a novolak-type phenolic resin; (C) a phosphazene-based fluororubber represented by the following general formula: (Where R ¹ is C _p H _2p C _q F _{2q + 1} and R ² is C _t H _2t C _s F
_{2s + 1} , l, m, n, p, q, s, and t represent an integer of 1 or more.) (D) Inorganic filler is an essential component, and the phosphazene-based resin (C) is used for the resin composition. The semiconductor pellet is sealed with a cured product of a sealing resin composition containing 0.1 to 5% by weight of a fluororubber and 25 to 90% by weight of the inorganic filler (D). Semiconductor sealing device.