JPS60179215A - Mold for resin sealing - Google Patents

Abstract

PURPOSE:To enable elimination of a void, by providing a narrowed part on a part of a resin passage, especially between a cull and a gate. CONSTITUTION:Resin is supplied to a gate 14 and a cavity 11 from a cull 15 through a resin passage 16. A narrowed part 17 is provided on a part of the resin passage 16. Then the resin loaded into a pot is turned into a molten state through heating, pressed and filled into the cull 15 of a mold. The resin receives uniform heating and pressing as a whole, the unmolten resin and the resin, which is in a state of a lump of particles and a floating island, disappear from the inside of the titled mold and the resin is turned into a fluid of the uniform liquidized resin as the resin is unable to pass through the passage 16 in large quantities due to the narrowed part 17. As a heat transfer area per unit weight at the time of passing of the resin through the narrowed part 17 can be set large, fluidity of the resin is improved through sufficient heating, and generation of bubbles and voids are controlled effectively without taking in air at the time of transference of the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold for sealing electrical parts, semiconductor elements, etc. with resin.

Currently, electrical parts and circuit elements such as integrated circuit ICs, ultra-integrated circuit LSIs, and laser resistors are produced by resin encapsulation, and in this case, transfer molding is used.

In this manufacturing method, resin powder or tablet-shaped resin is heated and melted in a pot, then immediately injected into a mold cavity and hardened to obtain resin-sealed (resin-molded) electrical parts and semiconductor devices.

However, in conventional transfer molding methods of this type, air is interposed between the pot and the resin in the form of a tapelet or tray, or when powdered resin is used, many air bubbles and voids are generated within the product. The reliability of sealing was deteriorated. Furthermore, it has the disadvantage of inducing corrosion of aluminum, which is the element wiring, resulting in poor characteristics.

Therefore, a proposal was made to provide a void trap groove in the resin passage in the mold to hold the void there. However, this proposal was unable to sufficiently remove these voids and could not eliminate product defects.

An object of the present invention is to provide a new mold for resin sealing for producing products in which voids of this type are eliminated.

In order to achieve such effects, the present invention includes a cavity for substantially sealing N gas components, semiconductor elements, etc.
A resin sealing mold in which a passage for transferring the sealing resin is arranged in the cavity, wherein a part of the resin passage, particularly a constricted part between the force μ and the gate, is provided. Provide the type.

The present invention will be described in detail below based on embodiments and with reference to the drawings.

FIG. 1 is a sectional view of the main part of the mold apparatus of the present invention, FIG. 2 is a top view of the lower mold part, and FIGS. 6 and 4 are sectional views of the main part of the lower mold.

In FIG. 1, the mold device includes an upper mold 1 and a lower mold 2, and an upper mold plate 3 of the press body. Attached to the lower mold plate 4, a pressurizing cylinder 5. *For mold clamping, the mold is opened and closed by the movable surface plate 6, and the upper mold 1 and the lower mold 2 are positioned relative to each other by the guide posts 7 and guide bushes 8.

After the sealing resin is put into the bot 9 of the upper die plate 3, it is heated and melted. This molten resin is injected under pressure into a cavity 11 inside the mold by a plunger 10, and is immediately cured while being heated inside the cavity 11 to seal the product. Thereafter, the upper mold 1 and the lower mold 2 of the mold are opened, and the product is released from the mold by the action of the ejector bin 13 and taken out.

FIG. 2 is a part of a plan view of the lower mold 2. The mold has a number of cavities 11 arranged therein, and a gate 14 is provided at the entrance of the cavities 11. It is supplied to the gate 14 and the cavity H via. A constricted portion 17 is provided in this resin passage 16 portion. 5 and 4 are sectional views of the main parts of the lower mold 2,
It shows a cross section of a constricted portion 17 provided in a resin passage 16.

According to the present invention, the resin charged into the bot 9 is heated and melted, and is filled into the mold force μ15 by pressurization of the plunger 10. It is not possible to pass. Therefore, since this resin can be heated and pressurized almost entirely and evenly, there is no unmelted resin or floating island-like resin that is agglomerated particles inside. By obtaining a uniform liquid resin fluid, it is possible to eliminate the causes of large voids or bubbles that occur in the conventional method. Furthermore, resin passage 1
When the resin No. 6 passes through the constriction part 17, the heat transfer area per unit weight is larger than that of conventional molds (it can be set), so it can be heated sufficiently and the flow characteristics of the resin are improved. Since pressure can be injected into the cavity 11 through the gate 14 without taking in air, the generation of air bubbles and voids can be effectively suppressed.

This makes it possible to significantly reduce the rate of product failure due to the presence of voids or bubbles, compared to conventional molds that do not have a drawing section, regardless of whether powdered resin or tablets are used. By providing this constriction part 17, the resin can be heated efficiently, and as a result, the fluidity of the resin is improved, so when pressurized injection into the cavity 11, air, which causes voids and bubbles, will not be taken into the resin. . Furthermore, it contributes to eliminating unmelted powder resin inside the molten resin.

Further detailed experiments have shown that the efficiency is highest when the reduction ratio is between 0.8 and 0.5 (as the reduction ratio becomes less than 0.2, more injection time is required and the injection pressure loss increases. Therefore, when the drawing ratio was selected from 0.8 to 0.3, the number of bubbles or voids with a diameter of 0.5 mm or more was the lowest.IC products manufactured using the mold of the present invention The inspection results showed that there were very few voids and bubbles.

This can be achieved by

The present invention relates to a conventional resin sealing device and a mold used in a transformer 7 amomand molding machine, which can eliminate sealing defects of electrical components 9 circuit elements, etc. due to voids and air bubbles, and always It is a mold that can produce products that hold well. Further, by adopting the present invention, molding defects can be reduced, so the reliability of the mold can be improved, and the mold has good durability.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a mold apparatus using this mold, with the right side showing a cross section passing through the center of the pot, and the left side showing a cross section passing through the center of a guide post. FIG. 2 is a top view of the lower mold, and FIGS. 3 and 4 are cross-sectional views of essential parts of the lower mold.

Claims (1)

[Claims] In a mold for resin sealing in which a cavity for substantially sealing an electrical component, a semiconductor element, etc. and a passage for transferring the entire sealing resin to the cavity are arranged, a part of the resin passage,
In particular, a mold for resin sealing is characterized in that a crest is provided between the force p and the gate.