JPS62158754A - Thermoplastic resin composition for use in sealing electronic component - Google Patents

Abstract

PURPOSE:To provide the titled compsn. having excellent sealing moldability and moisture resistance, by blending a specified polyphenylene sulfide with a fibrous filler, an epoxysilane and silica. CONSTITUTION:35-50wt% polyphenylene sulfide (A) having a melt flow index of 2,000g/10min or above, composed of at least 70mol% of a repeating unit of formula I and less than 30mol% of repeating units of formulas III, IV, V, VI, VII and VIII is blended with 8-30wt% fibrous filler (B) having a fiber length of 0.03-1.0mm (e.g., glass fiber) after kneading and extrusion, 0.3-3wt% epoxysilane (C) (e.g., gamma-glycidoxypropoyltrimethoxysilane) and 30-65wt% fused and/or crystalline silica (D).

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a thermoplastic resin composition for encapsulating electronic components,
More specifically, it is a thermoplastic resin composition for encapsulating electronic components that has improved encapsulation moldability and moisture resistance, and is mainly used as a encapsulation material for semiconductors such as ICs.

C. Prior Art] The use of a polyphenylene sulfide resin composition, which is characterized by heat resistance and flame retardancy, as a thermoplastic resin composition for encapsulating electronic components is known from JP-A-52-149348. There is. Also, the melt flow index is 100 to 10,000g/
A composition using 10% polyphenylene sulfide is disclosed in Japanese Patent Application Laid-Open No. 158256/1983 as an electronic component encapsulating material.

[Problem that the invention seeks to solve].

However, the melt flow index disclosed in JP-A-57-158256 is 100 to 10.
Compositions using polyphenylene sulfide of 000g/10min have the disadvantage that the lead wires are significantly displaced and damaged due to insufficient fluidity. Furthermore, when attempting to avoid displacement or damage to the lead wire with such a composition with poor fluidity, it is necessary to control the filling pressure during molding to an extremely low value, resulting in insufficient filling.

Furthermore, when an electronic component is sealed with such a composition with poor fluidity, the stress during molding and the stress on the sealing element or the lead wire joint during molding, as is evident in the deformation of the lead wire. Since the residual stress in the state of the sealed component is large, the electronic component is likely to fail due to thermal history such as high temperature use, and the heat resistance is poor, which is undesirable.

The present inventors studied to solve the drawbacks of the above-mentioned conventional technology,
This led to the present invention.

Therefore, an object of the present invention is to provide a thermoplastic resin composition for encapsulating electronic components that prevents lead wire displacement or damage during encapsulation molding of electronic components and has excellent heat resistance and can be used even at high temperatures.

[Means for solving problems]

In order to solve the above problems, the means of the present invention consists of 30 to 50% by weight of polyphenylene sulfide, 8 to 30% by weight of fibrous filler, and 0.3 to 3% of epoxy silane on a melt flow index of 12.000 g/10 parts. wt% and silica3
This is a thermoplastic resin composition for encapsulating electronic components, comprising 0 to 65% by weight.

Polyphenylene sulfide (hereinafter pps) used in the present invention
) is a polymer containing 70 mol% or more, more preferably 90 mol% or more of repeating units represented by the structural formula +S+; if the repeating unit is less than 70 mol%, heat resistance will be impaired. Therefore, it is undesirable.

Further, less than 30 mol% of the repeating units of PPS can be composed of repeating units having the following structural formula, etc.

The melt flow index of PPS used in the present invention is 12
．． 000 g/10 portions, preferably 13,000 g/10 portions, more preferably 15,000 g/10 portions.
000 g/10 portions are used. If this melt flow index is less than 12.000 g/10 minutes, the fluidity of the final composition will be poor.

The melt flow index of PPS in the present invention is ASTM
Performed according to method D-1238-74, temperature 316°C,
This is a value measured under the condition of a load of 5 kg.

The blending ratio of such PPS in the composition is 30 to 5
0! %, preferably 35 to 40 ffiffi%. If it is less than 30% by weight, the fluidity during encapsulation molding will be poor; if it exceeds 50% by weight, the filler content will be too small and the coefficient of linear expansion of the encapsulation molded product will increase. It is possible to add ordinary additives such as antioxidants, heat stabilizers, lubricants, ultraviolet water absorbers, colorants, and mold release agents to the PPS used.

As the fibrous filler used in the present invention, glass fibers, ceramic fibers, asbestos, potassium titanate fibers, other inorganic fibers, polyamides, polyesters, and other organic synthetic fibers are suitable, and among these, glass fibers are particularly suitable. preferable.

The amount of such fibrous filler in the composition is 8 to 8.
A range of 30% by weight is selected, preferably from 10 to 20% by weight. If it is less than 8% by weight, the mechanical strength of the composition will be insufficient, and if it exceeds 30% by weight, the fluidity during sealing molding will be poor.

Further, the fiber length of the fibrous filler after extrusion kneading is preferably 0.03 mm to 1.0 l from the viewpoint of mechanical strength of the composition and fluidity during sealing molding.

The epoxy silane used in the present invention is used for the purpose of mechanically reinforcing the composition as well as improving moisture resistance. Specific examples include T-glycidoxypropyltrimethoxysilane, T-glycidoxypropyltriethoxysilane, β
Examples include -(3,4-cyclohexyl)ethyltrimethoxysilane, and two or more of these can be used in combination. In the case of the composition of the present invention, these epoxysilanes in particular have a remarkable improvement effect, and the same improvement effect cannot be obtained even if other typical silane compounds such as unsaturated silanes and aminosilanes are used. That is, the epoxy silane of the present invention strengthens the adhesive strength at the interface between PPS and the fibrous filler or silica, improves the mechanical properties of the encapsulated molded product, and at the same time improves the moisture resistance.

The amount of epoxysilane in the composition is 0.3 to 3
Weight % is required. If it is less than 0.3% by weight, the effect of improving water resistance and mechanical properties will not be sufficiently achieved (and if it is less than 3% by weight)
If it exceeds, the above improvement effect will reach saturation (
, impairing the fluidity of the composition.

In addition, as a method for blending these epoxysilanes, a solution of epoxysilane (aqueous solution,
A method in which fibrous filler, fused silica, or crystalline silica is immersed in water/organic solvent mixed solution) and then dried, or a method in which fibrous filler or silica and epoxy silane are mixed and blended using a mixer with Henschel Mixture Jat. etc., but these are not particularly limited.

The fused silica and/or crystalline silica used in the present invention is
It is used for the purpose of improving the coefficient of linear expansion and thermal conductivity of the composition. The composition used for this purpose is required to have a low coefficient of linear expansion in order to reduce thermal stress on the element, and is also required to have high thermal conductivity in order to avoid accumulation of heat generated by the element. . Types of silica can be divided into fused silica and crystalline silica, both of which are suitable fillers for this purpose. Comparing fused silica and crystalline silica, the former has a particularly low linear expansion coefficient, and the latter has a particularly high thermal conductivity. Therefore, it is preferable to use fused silica when the requirement for linear expansion coefficient is relatively strict, and it is preferable to use crystalline silica when the requirement for thermal conductivity is relatively strict. Note that these silicas can be used in combination depending on the case.

The amount of fused silica and/or crystalline silica in the composition is selected from 30 to 65% by weight, preferably from 45 to 60% by weight. If it is less than 30% by weight, the effect of improving linear expansion coefficient and thermal conductivity will be insufficient, and if it exceeds 65% by weight, fluidity during sealing molding will deteriorate.

The method for producing the composition of the present invention is not particularly limited and may be a general method. For example, after mixing each component together at room temperature using a ribbon blade type mixer or a drum type rotary mixer, the components are melt-kneaded using a single screw extruder, multi-screw extruder, or kneader, and then pelletized. It can be manufactured by The pelletized composition can be introduced into an injection molding machine to encapsulate a semiconductor component, such as a chip.

〔Example〕

The present invention will be specifically explained below using Examples.

Reference Examples 1 to 5 (Polymerization of PPS) 30% sodium hydrogen sulfide aqueous solution 3.7 in an autoclave
4 kg, 1.60 kg of 50% sodium hydroxide and N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) 4
kg was charged, and the temperature was gradually raised to 205° C. while stirring, and 3.81 kg of distilled water containing 3.5 kg of water was removed. 3.00 kg of 1,4-dichlorobenzene and 0.5 kg of NMP were added to the residual mixture, and the temperature was raised to 230°C and held for the time indicated in Table 1. The reaction product was diluted with water for 2 hours. Washed twice with water at a temperature of 70°C. This was placed in an autoclave with three times the amount of ion-exchanged water, sealed at normal pressure, and heated to 180°C while stirring.
After holding for about 2 hours, it was cooled. The contents were taken out from the autoclave, filtered, and washed with ion-exchanged water at room temperature until the pH of the filtrate reached 7, and then dried under reduced pressure at 120° C. for 24 hours to obtain about 2 kg of powdered PPS.

The melt flow of the obtained PPS was as shown in Table 1.

(Margin below the sailor) Table 1 Example 1 PPS powder of Reference Example 1 and chopped glass fiber (manufactured by Nippon Electric Glass ■, TN-101, diameter 13 microns,
length of about 10 vm), fused silica (Toshiba Ceramics GR-80, average particle size 20 microns), and epoxy silane (γ-glycidoxypropyltrimethoxysilane, Toshi Silicone@@5H-6040), Black colorant (
Carbon blank and Toyo Ink TS-0171) were prepared in the proportions shown in Table 2 to give a total weight ffi of 2.5 kg, and placed in a 10 Il ribbon blade mixer.
Mixed for a minute. The resulting mixture was passed through a screw with a diameter of 30 mm.
The mixture was put into a twin-screw extruder, and melt-kneaded at a cylinder temperature of about 290° C. and a screw rotation speed of 45 revolutions per minute, and pelletized using a hot cutter installed at the tip of the extruder.

This pellet was supplied to an injection molding machine exclusively for inserts, and a semiconductor element was encapsulated at a cylinder temperature of 340°C and a mold temperature of 200°C. For the semiconductor device, a semiconductor chip was placed on each of 10 support frames, and the electrodes of the semiconductor chip and the terminals of the support frame were connected using gold wires (hereinafter referred to as lead wires) with a diameter of 30 microns. there was. The molding pressure was selected to be the lowest pressure that would completely fill the mold with resin. The lower limit pressure for molding was as shown in Table 2.

Displacement or damage to the lead wire of the sealed molded product was evaluated using a soft X-ray method, and the amount of displacement was evaluated as the average value of the maximum displacement ffi (mm) for 10 sealed parts with respect to the normal lead wire position. Heat resistance is 150 for 10 sealed parts
A high-temperature operation test was conducted at ℃, and evaluation was made based on the time required for failure to occur in five sealed components.

In addition, the heat resistance is 100℃ in pressurized steam at 121℃ and 2 atmospheres.
The value of leakage current after time holding (this operation is referred to as PCT in Table 2) was evaluated as an average value for 10 sealed parts. The results are shown in Table 2.

Example 2.3 Encapsulation molding and its evaluation were carried out in exactly the same manner as in Example 1, except that PPS of Reference Examples 2 and 3 were used instead of PPS of Reference Example 1 in Example 1. The results are shown in Table 2.

Comparative Example 1.2 Sealing molding and molding were carried out in exactly the same manner as in Example 1, except that PPS of Reference Examples 4 and 5 was used instead of PPS of Reference Example 1. We conducted an evaluation. The results are shown in Table 2.

Comparative Examples 3 and 4 Same as Example 1 except that the epoxy silane used in Example 1 was not added and the amount was reduced to 0.3% by weight (sealing molding and evaluation were performed in the same manner. Results) is as described in Table 2.

Comparative Example 5.6 Sealing molding and evaluation were performed in exactly the same manner as in Example 1, except that the blending ratio of the glass fibers used in Example 1 was 32% by weight and 7% by weight, respectively. The results are shown in Table 2.

(Margin below for sailor) [Effects of the Invention] The thermoplastic resin composition for encapsulating electronic components of the present invention exhibits the following excellent effects.

(1) Due to good fluidity during molding, displacement of the lead wire is small.

(2) Electronic components sealed with the composition of the present invention have fewer failures and less current leakage.

Claims (1)

[Claims] Melt flow index 12,000 g/10 parts by weight polyphenylene sulfide 30-50%, fibrous filler 8
30% by weight of epoxy silane, 0.3 to 3% by weight of epoxysilane, and 30 to 65% by weight of silica.