JPS6328616A - Molding equipment - Google Patents

Abstract

PURPOSE:To uniformize the quality of molded products by uniformize the pressure of resin sent under pressure from pots to respective cavities by a method wherein a plurality of pots are connected to one another by communicating passages. CONSTITUTION:The cylinders 6, 6... of a plurality of pots 4, 4... are connected to one another by communicating passages 10. Resin tablets R are charged in the pots 4, 4... and respective plungers 7, 7... are simultaneously driven by a driving mechanism 8. The resin tablet R in each pot 4 is pressed by the plunger 7 and sent under pressure through a runner 5 to each cavity 3. In this time, because the interiors of the cylinders 6, 6... of a plurality of the pots 4, 4... are connected to one another by the communicating passage 10, the resins in the respective pots 4 uniformly flow through the communicating passages 10, even if the weights of the respective resin tablets R and the pressing force applied to the tablets differ from one another, resulting in uniformizing the resin in the respective cavities 3 and consequently obtaining molded products having uniform quality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a molding device, and particularly to a molding device suitable for application to a transfer molding device having a plurality of tablet pressing ports.

[Conventional technology]

Generally, a resin mold structure is adopted as a package for a semiconductor device, and this package is formed by a molding method using a transfer molding device or the like. Conventionally, this type of molding equipment has a single pot that communicates with multiple cavities through a runner, and a resin tablet is placed in this pot and pressed with a plunger, and the resin is forced through the runner and into each cavity. The system is configured to do this.

However, in this molding equipment, the runners from the pot to each cavity are long, and the resin that remains on these runners is wasted, reducing the resin yield and causing an increase in the cost of semiconductor devices. There is.

For this reason, in recent years, multiple pots have been installed in one molding device to reduce the number of cavities handled by these pots.
Molding apparatuses have been proposed in which the length of the runner that communicates between each cavity and each pot is shortened (by which the waste of resin is reduced).

[Problem that the invention seeks to solve]

In order to simplify the structure of the above-mentioned molding apparatus having a plurality of pots, a configuration is adopted in which the plungers provided corresponding to the plurality of pots are pressed and driven by the same mechanism. That is, the resin put into each pot is simultaneously pressed by each plunger to force-feed the resin to each cavity.

For this reason, if there is a difference in weight (volume) of the resin tablets put into each pot, the compression ratio of the resin tablets in each pot will be different, and this will appear as a difference in the pressure of the resin pressed in each pot. .

Therefore, even in the same molding apparatus, the resin mold pressure in each cavity is different, leading to variations in the quality of molded products and, depending on the case, problems such as mold defects occurring in some parts.

The reality is that it is almost impossible to manufacture and manage a plurality of resin tablets so that they all have the same weight.

SUMMARY OF THE INVENTION An object of the present invention is to provide a molding apparatus that can equalize the resin pressure in each cavity and can equalize and improve the quality of molded products.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Means for solving problems]

A brief overview of typical inventions disclosed in this application is as follows.

That is, a plurality of pots connected to a plurality of cavities with runners are provided with a communication path that communicates these pots with each other, and the resin pressed in each pot is communicated with each other through this communication path. This is what I did.

[Effect]

According to the above-mentioned means, the resins pressed in each pot are communicated with each other through the communication path, so the pressing force of each resin is averaged through the communication path, and the resin is pumped from each pot to the cavity it is in charge of. The pressure of the resin applied can be made uniform.

〔Example〕

FIGS. 1 and 2 are a plan view and a sectional view taken along line 1 and 2 of an embodiment of the present invention.

In these figures, the molding apparatus is composed of a lower mold 1 and an upper mold 2, and a large number of cavities 3 are formed at the interface between the upper mold 1 and the lower mold 2.

Further, the cavities 3 are divided into a plurality of groups in the lower mold 1, and each group is provided with a pot 4, so that each pot 4 is in charge of a predetermined number of cavities 3. The plurality of cavities 3 and pots 4 for each group are communicated with each other by runners 5, and the resin pressed by the pots 4 is force-fed to each cavity 3 through the runners 5. Needless to say.

The pot 4 is composed of a cylinder 6 into which a resin tablet can be placed, and a plunger 7 that is pressed inside the cylinder 6. Each plunger 7 is connected to a drive mechanism 8 (details of which will be omitted), and the structure is such that all the plungers 7 are simultaneously pressed by the operation of the drive mechanism 8. Openings 9 are provided in part of the side walls of the cylinders 6 of the plurality of pots 4, and the insides of the cylinders 6 of the respective pots 4 are communicated with each other through communication passages 10 communicating with these openings 9.

According to this configuration, each pot 4 has a resin tab I-R.
, and the plungers 7 are simultaneously driven by the driving mechanism 8, so that the resin tablet R is pressed by the plunger 7 in each pot 4, and the resin is force-fed into each cavity 3 through the runner 5.

At this time, since the insides of the cylinders 6 of each pot 4 are communicated with each other by the communication path 10, even if the weight of each resin tablet R is different and the pressing force by the plunger 7 is different, the resin of each pot is communicated with each other. It flows through the passage 10 to equalize each pressure. As a result, the resin pressure in each pot 4 and the runner 5 communicating therewith is all equalized, and the resin is fed under pressure to each cavity 3 to perform a predetermined molding. Therefore, the resin pressure in each cavity 3 is equalized, and the quality of the molded product can be equalized and improved.

According to the embodiment described above, the following effects can be obtained.

(1) Since multiple pots are connected to each other using a communication path, the resin pressing force in each pot is equalized,
The resin pressure in the runners and cavities communicating with this can be made uniform, and the quality of molded products can be made uniform and improved.

(2) Since a plurality of pots are provided and a large number of cavities are divided between these pots and used for each injection, the runner that communicates the pots and cavities can be shortened, and waste of resin can be reduced.

(3) Even if the plungers in a plurality of pots are operated by one drive mechanism, the resin pressure can be made uniform, and the structure of the molding apparatus can be simplified.

Although the invention made by the present inventor has been specifically explained above based on examples, the present invention is not limited to the above-mentioned examples (although it is possible to make various changes without departing from the gist of the invention). Needless to say, for example, the number of pots and their arrangement positions can be changed arbitrarily, and the arrangement pattern of communication passages can also be changed arbitrarily.

In the above description, the invention made by the present inventor was mainly applied to a molding apparatus for a resin mold for forming a package for a semiconductor element, which is the field of application in which the invention was made, but the present invention is not limited thereto. Rather, it can be used for molding various electronic parts and for molding ordinary molded products.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

That is, a plurality of pots that can communicate with a plurality of cavities by lunch are provided with a communication path that communicates these pots with each other, and the resin pressed in each pot is configured to communicate with each other through this communication path. Because I am doing
The pressed resin in each pot is communicated with each other through a communication path, and the pressing force is averaged through this communication path, which equalizes the pressure of the resin pumped into each cavity and improves the quality of the molded product. - and improve quality.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line ■■■. l...lower mold, 2...upper mold, 3...cavity, 4
...Pot, 5...Runner, 6...Cylinder, 7
... Plunger, 8... Drive mechanism, 9... Opening,
10...Communication path, R...Resin tablet. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A molding device in which a plurality of pots are arranged for a plurality of cavities, each of the cavities is divided into groups, and each of the cavities is connected to the different pots by a runner, A molding device characterized in that a communication path is established to communicate with each other, and the resin pressed in each pot is communicated with each other through this communication path. 2. The molding device according to claim 1, wherein a part of the cylinder side wall of the pot is opened, and a communicating path is connected through this opening. 3. The molding device according to claim 2, wherein the plungers of each pot are configured to be operated simultaneously by one drive mechanism.