JPH10217276A - Transfer molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the working efficiency and prevent the deterioration of the durability of a plunger by loading a material tablet in a state in which the plunger is inserted into a material loading chamber, heating and melting the material tablet and pushing the plunger into the molten resin for distribution and packing thereof. SOLUTION: A material tablet B of a thermoset synthetic resin is loaded into a material loading chamber 3 in a lower mold 1 from between two mold. In this case, a plunger is inserted into a lower part of the material loading chamber 3 from a bottom side of the lower mold 1, and thus the material tablet B loaded in the material loading chamber 3 rides on a tip end face of the plunger. In this state, after the material tablet B is heated to be molten, the plunger is pushed into the material loading chamber 3 so as to push the synthetic resin in the molten state from a distribution chamber 6 into respective cavities 4, 5 via respective runner grooves 7, 8 to thereby form molded parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a transfer molding method for molding a molded part or the like in a semiconductor component.

[0002]

2. Description of the Related Art In general, to mold a molded part of a semiconductor component, a raw material tablet of a thermosetting synthetic resin is supplied into a material loading chamber, and the raw material tablet is heated and melted in the material loading chamber. The application of so-called transfer molding, in which a plunger is pushed into a material loading chamber to inject into a molding cavity and mold, is described in, for example, Kiyoichi Ogawa, Seibundo Shinkosha Co., Ltd. It is well known as described in "Mold Handbook", September 25, 1965, 1st edition, pages 178 to 180.

[0003]

However, in the conventional transfer molding described in the above-mentioned document, the material loading chamber is inserted into the upper die of the pair of upper and lower dies so as to penetrate the upper die. In the transfer molding, the molds are first combined, and then the plunger is pulled out of the material loading chamber into the material loading chamber in the upper mold. After loading the raw material tablet and then heating and melting the raw material tablet, the plunger must be pushed into the material loading chamber. In other words, each time the raw material tablet is loaded into the material loading chamber, The plunger must be pulled out of the material loading chamber, and the time required for a single transfer molding is reduced by pulling out the plunger. Since the time required for reinserting the plunger becomes longer, the working efficiency is low, and the durability of the plunger is reduced due to the removal and insertion of the plunger, and the cost required for transfer molding is considerably increased. There was a problem.

An object of the present invention is to provide a transfer molding method capable of solving this problem.

[0005]

SUMMARY OF THE INVENTION In order to achieve this technical object, the present invention relates to a method of manufacturing a lower mold of a pair of upper and lower molds having a plurality of molding cavities in one or both. A raw material tablet of a thermosetting synthetic resin is loaded into a material loading chamber provided so as to penetrate the same, with a plunger inserted from the lower surface of the lower mold into a lower portion of the material loading chamber, and then, in this state, Heat the raw material tablet
After being melted, the molten resin is distributed and filled into each of the molding cavities by a pushing movement of the plunger. Is the thing.

[0006]

According to the present invention, as described above, the material loading chamber is provided in the lower mold, and the plunger is inserted into the lower part of the material loading chamber from the lower surface of the lower mold. In this state, the raw material tablet of the thermosetting synthetic resin is loaded, and then, in this state, the raw material tablet is heated and melted, and then the plunger is pushed in.The raw material tablet is loaded into the material loading chamber. Since the two dies can be separated from each other, it is not necessary to insert and remove the plunger each time the raw material tablet is loaded as in the conventional case.

Therefore, according to the present invention, the time required for one transfer molding can be shortened, the work efficiency can be improved, and the decrease in the durability of the plunger can be prevented. This has the effect of significantly reducing costs.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of the present invention applied to forming a plurality of molded portions on a lead frame for manufacturing semiconductor components. In the drawings, reference numeral 1 denotes a lower mold for molding, and reference numeral 2 denotes an upper mold for the lower mold 1, respectively. Two lead frames A1 and A2 formed by forming a1 and a2 at a constant pitch in the longitudinal direction are sandwiched in a state of being arranged in parallel.

In the lower mold 1 at a substantially central portion,
A material loading chamber 3 for loading a raw material tablet B of a thermosetting synthetic resin is provided so as to penetrate the lower mold 1,
A plunger 9 is inserted into the material loading chamber 3 from the lower surface side of the lower mold 1 so as to be able to reciprocate. Also, on the mating surface of the lower mold 1 with respect to the upper mold 2, each semiconductor component a1,
The cavities 4 and 5 for molding the mold portion are formed in the location a2, and the distribution chamber 6 communicating with the filling chamber 3 is formed in the recess.

Further, on the mating surface of the lower mold 1 with the upper mold 2, runner grooves 7, 8 for communicating the distribution chamber 6 with the molding cavities 4, 5 are provided. The two lead frames A1 and A2 are formed so as to be recessed so as to extend along one longitudinal side edge, and the end of the one of the two runner grooves 7 or in the vicinity thereof.
Sub-runner grooves 10 and 11 are formed so as to communicate with each other at the end of the other two runner grooves 8 or in the vicinity thereof.

A portion of the outer peripheral surface of the plunger 9 inserted reciprocally into the material loading chamber 3 near the distal end surface 9a has, for example, a width W of 0.5 to 0.9 mm and a depth H of Is formed into a narrow annular groove 12 having a width W of 0.1 to 0.5 mm. In this configuration, in a state where the two dies 1 and 2 are separated from each other, the raw material tablet B of the thermosetting synthetic resin is placed in the material loading chamber 3 of the lower die 1.
Load between two. In this case, the plunger 9 is inserted into the lower part of the material loading chamber 3 from the lower surface side of the lower mold 1, so that the raw material tablet B loaded in the material loading chamber 3 is 9 is on the tip surface 9a.

In this state, the raw material tablet B is heated and melted, and then the plunger 9 is pushed into the material loading chamber 3 so that the synthetic resin in the molten state is discharged from the distribution chamber 6 to the respective runner grooves 7 and 8. The molded part is molded by being pushed into the cavities 4 and 5 through the holes. In this molding, the annular groove 12 on the outer peripheral surface of the plunger 9 is filled with the molten synthetic resin and filled. The synthetic resin that has penetrated and filled therein comes into close contact with the inner peripheral surface of the material loading chamber 3 without any gap.

[Brief description of the drawings]

FIG. 1 is a plan view of a lower mold.

FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged sectional view taken along line III-III of FIG. 1;

[Explanation of symbols]

A1, A2 Lead frame 1 Lower mold 2 Upper mold B Raw material tablet 3 Material loading chamber 4,5 Mold part molding cavity 6 Distribution chamber 7,8 Runner groove 9 Plunger 10,11 Sub-runner groove 12 Narrow annular groove

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29L 31:34

Claims (1)

[Claims] 1. A material loading chamber provided in a lower mold of a pair of upper and lower molds having a plurality of molding cavities in one or both of them, and a material is inserted into the material loading chamber. A raw material tablet of a thermosetting synthetic resin is loaded in a state where the plunger is inserted from the lower surface of the lower mold into the lower part, and then the raw material tablet is heated and melted in this state, and then the molten resin is pushed into the plunger. A transfer molding method characterized by distributing and filling the molding cavities by movement.