JPS63219145A - Pps sealed electronic component - Google Patents

Abstract

PURPOSE:To augment the bonding properties while improving the humidity resistance of sealed electronic components by a method wherein polyphenylene sulfide as well as non-denatured silicon oil and denatured silicon oil are jointly used. CONSTITUTION:Electronic parts are sealed with resin composition in melting viscosity not exceeding 1000 poise produced using total 20-80 weight % of silica and glass fiber exceeding mean aspect ratio of 10 as well as 20-80 weight % of polyphenylene sulfide and 0.1-10 weight %, preferably 2-10 weight %, of both nondenatured silicon oil and denatured silicon oil jointly used. Through these procedures, the bonding properties of sealing resin to a lead frame or a bonding wire can be augmented to improve the humidity resistance and the thermal cycling characteristics of sealed electronic components.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a polyphenylene sulfide composition containing an unmodified silicone oil and a modified silicone oil, particularly a resin composition for encapsulating electronic components with excellent moisture resistance and thermal cycle characteristics. It is about things.

[Subject skill]

Conventional resin encapsulation was usually performed by transfer molding using thermosetting resins such as epoxy resins and soricone resins, but since thermosetting resins are used, the molding time is long and the process requires a long time. Post cure is required. As the number of molding shots increases, there are drawbacks such as mold staining.

Attempts have been made to use polyphenylene sulfide, a thermoplastic resin, as a substitute for thermosetting resins, which have the drawbacks mentioned above. Polyphenylene sulfide has properties suitable for sealing electronic components, such as good heat resistance, electrical properties, and flame retardancy, and because it is a thermoplastic resin, it can be used to reuse scraps such as sprues and runners. Although it has many advantages over thermosetting resins, such as being able to shorten the molding cycle for sealing by injection molding, electronic components sealed using polyphenylene sulfide are Compared to electronic components sealed using this method, it has the disadvantage that its moisture resistance and thermal cycle characteristics are significantly inferior.

In other words, polyphenylene sulfide resin has poor adhesion to lead frames of electronic components or bonding wires of ICs, and has weak mechanical strength, compared to epoxy resins and silicone resins. If placed in a high humidity atmosphere, the resin may be sealed incorrectly.
Water easily enters through the interface of the lead frame or the bonding wire, resulting in a decrease in electrical insulation.The inventors of Alki conducted repeated studies to improve these defects, and the inventors developed an unmodified silicone oil. By using together with modified silicone oil, the adhesion between the sealing resin and the lead frame or bonding wire is greatly improved.
It has been found that the moisture resistance and thermal cycle characteristics of sealed electronic components are significantly improved.

[Structure of the invention]

The present invention provides an electronic component sealing resin composition with a low melt viscosity, which is composed of a combination of polyphenylene sulfide (PPS), unmodified silicone oil, and modified silicone oil, silica, and glass fiber.

The polyphenylene sulfide resin (hereinafter abbreviated as PPS) used in the present invention is a thermoplastic resin having the general formula [-◎-8'l-7.There are several types depending on the degree of crosslinking, and which type is used. However, it is preferable to use the MR-11 grade of the present invention.

The unmodified silicone oil used in the present invention is polydimethylsiloxane oil, and the modified silicone oil has reactive properties such as epoxy groups, carboxyl groups, amino groups, and hydroxyl groups in some of the side chain methyl groups of polydimethylsiloxane oil. The total proportion of the substituents in the entire composition is preferably 0.1 to 10% by weight, particularly 2 to 10% by weight. If the proportion of silicone oil is less than 2% by weight, the sealed IC
Almost no improvement effect on moisture resistance and thermal cyclability was observed. Furthermore, even if it is used in an amount of 10% by weight or more, not only is no significant effect of improving moisture resistance and thermal cyclability observed, but also the mechanical strength of the sealed product is reduced.

Silica is necessary to improve mechanical strength, reduce linear expansion coefficient, and increase thermal conductivity. In the present invention, silica is used with an average particle size of 30μ or less, and glass fiber is used to improve melt viscosity and mechanical strength. , the coefficient of linear expansion, and the ratio of silica and glass fiber in total are preferably 20 to 80% by weight, preferably 30 to 80% by weight.

If it is less than 20% by weight, the mechanical strength is low and the thermal conductivity is also low. If it exceeds 80% by weight, the melt viscosity of the composition will be too high,
This will cause damage to the bonding wires of the encapsulated special electronic components.

Furthermore, it is preferable to surface-treat the silica and glass fibers with a silane coupling agent or the like in order to improve the mechanical strength and moisture resistance of the molded product.

The resin composition of the present invention has an extrusion pressure of 1,000 poise or less when measured using a die of 1.0φ, 1×10βIN% temperature, 300°C, and an extrusion pressure of IQ kg/cut according to the method of ASTM-1703, so that it will not damage the wires of electronic components. preferred for.

It is also possible to mix PPS resin and/or blend other thermoplastic resins without departing from the purpose of the present invention, and there is no problem in adding colorants, mold release agents, etc. as necessary. .

pps <Rydon MR-11), a combination of unmodified silicone oil and modified silicone oil, silica and glass fibers with an average aspect ratio of 10 or more using a Henschel mixer at the blending ratios (values are weight %) shown in Table 1. After uniformly mixing the mixture, it was extruded into a compound using a twin-screw extruder with a screw diameter of 30.1φ at a cylinder temperature of 290 to 320°C and a screw rotation speed of 1100 rpm. This compound was molded into a cylinder at a temperature of 30°C using an injection molding machine.
16pinDI at 0~320'C1 mold temperature 150~200'C1 injection pressure 50~100 kg/cnl
Injection molding was performed using a mold into which an empty IC frame of P was inserted. The obtained sealed product was treated with fluorescent liquid (Super Glow OD=
, 280 (manufactured by M Special Paints ■) at room temperature for 20 hours, the state of penetration of the fluorescent liquid from the interface between the frame and the sealing resin was investigated and shown in Table 1.

In this measurement, the criteria as shown in FIG. 1 were set, and the penetration positions (1 to 6) of the fluorescent liquid were indicated.

[Example of implementation B]

Injection molding was performed using a mold with a DIP frame inserted. Melt viscosity, bending strength, linear expansion coefficient, thermal cycle test (-65°C (30 minutes) -150°C) of this composition
(15 minutes): 1 cycle) and the Presso Shark and Kerr test results are shown in Table 2.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an island portion of an IC empty frame sealed with the composition of the present invention and a comparative product. Patent applicant: Sumitomo Heckleite Co., Ltd. Figure 1

Claims (1)

[Claims] Polyphenylene sulfide (PPS) 20-80% by weight, a combination of unmodified silicone oil and modified silicone oil 0.1-10% by weight, silica and glass fibers with an average aspect ratio of 10 or more total 20-80% by weight
An electronic component sealed using a PPS composition comprising: a PPS composition having a melt viscosity of 1000 poise or less.