JPH0680753B2 - Resin-sealed semiconductor device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin-encapsulated semiconductor device having excellent reliability, particularly moisture resistance reliability.

[Conventional technology]

Conventionally, as a resin-encapsulated semiconductor device in which semiconductor elements such as transistors, ICs, and LSIs are protected by a plastic package, a dual in-line package (DIP) type in which pins are mounted on a printed circuit board etc. is mounted Is used.

However, in recent years, with the flow of development of small high-performance products such as wristwatches, calculators, VTR cameras, etc., high density mounting and thinning of semiconductor devices are required, and so-called flat package type surface mounting type semiconductor devices have been developed. It is becoming popular.

Unlike the conventional DIP type, the surface mount type semiconductor device is not one in which only the lead pins are partially solder-immersed, but usually the whole semiconductor device is immersed in a solder bath at about 260 ° C and then connected to a printed circuit board. , It is mounted by fixing.

[Problems to be solved by the invention]

However, when the entire semiconductor device is immersed in the solder bath as described above, the semiconductor device undergoes a rapid temperature change from room temperature to 260 ° C, and a thermal shock causes a gap between the lead frame and the sealing resin. , The moisture resistance of the package will be impaired.

In order to solve such a problem, an epoxy resin composition containing polysiloxane has been proposed (JP-A-58).
-137804). However, in reality, such a resin composition cannot be sufficiently applied to a surface-mounting type semiconductor device, and its improvement is desired.

The present invention has been made in view of such circumstances,
It is an object of the present invention to provide a resin-encapsulated semiconductor device having excellent moisture resistance after solder immersion.

[Means for solving problems]

To achieve the above object, the resin-encapsulated semiconductor device of the present invention contains the following components (A) to (D) and further contains a water repellent agent containing polyethylene having a molecular weight of 1000 or more as a main component. The epoxy resin composition is used to seal the semiconductor element.

(A) Epoxy resin.

(B) a phenolic resin.

(C) Curing accelerator.

(D) Organopolysiloxane.

That is, the present inventors have developed a resin-encapsulated semiconductor device that exhibits excellent moisture resistance even after solder immersion,
As a result of a series of studies, they have found that the intended object can be achieved by using organopolysiloxane and polyethylene in combination and using polyethylene having a molecular weight of 1000 or more, and arrived at the present invention.

The epoxy resin composition used in the present invention is obtained by using an epoxy resin, a phenol resin, a curing accelerator, an organopolysiloxane, and polyethylene, and is usually in the form of powder or a tablet. It looks like a tablet.

The epoxy resin serving as the component A is not particularly limited, and various epoxy resins conventionally used as sealing resins for semiconductor devices, such as cresol novolak type, phenol novolak type, and bisphenol A type, are used. can give. Among these resins, those having a melting point over room temperature and exhibiting a solid state or a high-viscosity solution state at room temperature bring about good results. As the novolak type epoxy resin, those having an epoxy equivalent of 160 to 250 and a softening point of 50 to 130 ° C are usually used, and as the cresol novolak type epoxy resin, those having an epoxy equivalent of 180 to 210 and a softening point of 60 to 110 ° C are used. Commonly used.

The component B phenolic resin used together with the epoxy resin acts as a curing agent for the epoxy resin, and phenol novolac and cresol novolac are preferably used. It is preferable to use these novolak resins having a softening point of 50 to 110 ° C. and a hydroxyl group equivalent of 70 to 150. Particularly, it is preferable to use cresol novolak among the above novolak resins.

Examples of the C component curing accelerator used together with the phenol resin include various conventionally used curing accelerators, which may be used alone or in combination. Preferred examples of this type of curing accelerator include the following tertiary amines, quaternary ammonium salts, imidazoles and boron compounds.

Tertiary amine triethanolamine, tetramethylhexanediamine, triethylenediamine, dimethylaniline, dimethylaminoethanol, diethylaminoethanol, 2,4,
6- (dimethylaminomethyl) phenol, N, N'-dimethylpiperazine, pyridine, picoline, 1,8-diaza-
Bicyclo (5,4,0) undecene-7, benzyldimethylamine, 2- (dimethylamino) methylphenol quaternary ammonium salt dodecyltrimethylammonium iodide, cetyltrimethylammonium chloride, benzyldimethyltetrabutylammonium chloride, stearyltrimethylammonium chloride Imidazoles 2-methylimidazole, 2-undecylimidazole, 2-ethylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole boron compound tetraphenylboron, tetraphenylborate, N-
Methylmorpholine tetraphenyl borate, and the above-mentioned component D includes organopolysiloxanes represented by the following general formulas (I) to (III), which may be used alone or in combination.

The content of such an organopolysiloxane can be set within the range of 2 to 50% by weight, more preferably 5 to 30% by weight, based on the organic component in the epoxy resin composition.
It is within the wt% range.

The water repellent used together with the above components (A) to (D) has polyethylene having a molecular weight of 1000 or more as a main component, and particularly a water repellent having polyethylene having a molecular weight of 10,000 to 100,000 as a main component gives good results. Bring Here, the term “main component” is intended to include a case where the entire component is the main component. A resin containing polyethylene having a molecular weight of less than 1000 as a main component does not sufficiently improve the moisture resistance of the resin-sealed semiconductor device, and the object of the present invention cannot be achieved. Here, the above-mentioned molecular weight indicates a weight average molecular weight determined by gel permeation chromatography using polystyrene as a reference substance and tetrahydrofuran as a developing solvent. The amount of the water repellent used is preferably set to 0.1 to 1.5% by weight (hereinafter abbreviated as "%") of the entire epoxy resin composition, and more preferably 0.3 to 1%. If the amount of water repellent used is less than 0.1%, the moisture resistance of the resin-encapsulated semiconductor device will not be sufficiently improved, while if it exceeds 1.5%, the appearance of the resin-encapsulated semiconductor device will be poor and at the same time surface printing will be performed. This is because it tends to be difficult.

In the epoxy resin composition used in the present invention, waxes such as carnauba wax can be used in combination with the water repellent having polyethylene as a main component, and, if necessary, other than the above raw materials. In addition, a flame retardant such as an inorganic filler, antimony trioxide or a phosphorus compound, a pigment, or a coupling agent such as a silane coupling agent can be used. The above-mentioned inorganic filler is not particularly limited, and commonly used quartz glass powder, talc, silica powder, alumina powder and the like are appropriately used.

The epoxy resin composition used in the present invention can be produced by a conventionally known method. More specifically, the epoxy resin, the phenol resin, the organopolysiloxane, and the polyethylene wax having a molecular weight of 1000 or more are used. In some cases, an inorganic filler, a pigment, a coupling agent, and other additives are appropriately mixed, and the mixture is kneaded in a kneading machine such as a mixing roll machine in a heated state to form a semi-cured resin composition, which is stored at room temperature. The desired epoxy resin composition can be obtained by cooling to 1, then pulverizing by a known means, and tableting if necessary.

The encapsulation of the semiconductor element using such an epoxy resin composition is not particularly limited, and can be performed by an ordinary method, for example, a known molding method such as transfer molding.

The semiconductor device thus obtained has excellent reliability,
In particular, it has excellent moisture resistance after solder immersion.

〔The invention's effect〕

The present invention is characterized by encapsulating a semiconductor element using an epoxy resin composition in which a water-repellent agent containing polyethylene having a molecular weight of 1000 or more as a main component and an organopolysiloxane are used in combination, Due to the action of the above-mentioned organopolysiloxane, the interfacial peeling between the cured resin and the element in which the stress strain generated at the time of thermal shock such as immersing the entire device in a solder bath is significantly reduced can be suppressed. In addition, since the polyethylene water repellent in the composition is melted by the heating at the time of resin sealing or the temperature at the time of solder immersion to cover and protect the element surface, a gap is temporarily provided between the package and the element. Even if it occurs, the water-repellent effect of the water-repellent agent prevents the intrusion of water. That is, according to the present invention, due to the above effects, the moisture resistance reliability when sealing the semiconductor block can be made extremely high, and the thermal shock during the surface mounting of the package and the miniaturization and thinning of the plastic package can be achieved. And so on.

Next, examples will be described together with comparative examples.

[Examples 1 to 7 and Comparative Examples 1 to 3] First, each raw material was blended in a composition shown in Table 1 below, and the blended material was kneaded with a hot roll at 120 ° C for 5 minutes, cooled, and then ground, It was a powdery composition. Then, using the obtained powdery composition, a linear IC was formed into an 8-pin SOP (Small Outline
It was formed by transfer molding under the conditions of pressure 70 kg / cm ² , temperature 175 ° C., and time 2 minutes.

Next, the obtained resin-encapsulated semiconductor device was placed in an atmosphere at a temperature of 85 ° C. and a humidity of 85% RH to allow the package to absorb moisture, and then dipped in solder (260 ° C. × 10S) to 121 ° C. × 100% RH. As a result of carrying out the Presqueak Tuker Test (PCT), the average lifetime (MTTF) shown in Table 1 was obtained.

From the results shown in Table 1, it can be seen that the example products are remarkably excellent in moisture resistance after solder immersion.

In contrast, Comparative Examples 1 and 2 did not use a polyethylene water repellent, and Comparative Example 3 used a polyethylene water repellent, but did not use it in combination with organopolysiloxane, and therefore the results are poor.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C08L 63/00 NKB B 8830-4J H01L 23/31

Claims (2)

[Claims] 1. A semiconductor element is encapsulated using an epoxy resin composition containing the following components (A) to (D), and further containing a water repellent agent containing polyethylene having a molecular weight of 1000 or more as a main component. A resin-sealed semiconductor device obtained by (A) Epoxy resin. (B) a phenolic resin. (C) Curing accelerator. (D) Organopolysiloxane. 2. The resin-encapsulated semiconductor device according to claim 1, wherein the water repellent has a molecular weight of 10,000 or more.