JPH01123713A - Molding die - Google Patents

Abstract

PURPOSE:To prevent failure such as disconnection of gold wire or the like from occurring by uniformizing the quality of resin encapsulation of each semiconductor chip by a method wherein a shutter is openably and closably provided at each one of gate parts connecting to a plurality of cavities of a molding die. CONSTITUTION:A large number of cavities 3 are provided in the neighborhood of a runner 1 or a passage of resin 4 and connected through gate parts 2, which are normal to the runner 1, to the runner 1. At the runner 1 side end part of each gate part 2, a slit 5a, in which a shutter 5 is provided protrusively and retractably, is bored. The flows of the resin 4 running through the gate parts 2 are controlled by opening and closing the gate parts with the shutters 5 by means of an opening and closing mechanism. At resin encapsulation, when the whole runner 1 is filled with the resin 4 so far to its tip, the respective shutters 5 are simultaneously opened so as to release the gate parts 2. As a result, the resin 4 is poured simultaneously in the respective cavities 3. Accordingly, the resin is poured in the cavities 3 at the same speed at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a mold used mainly in the process of resin-sealing a semiconductor chip.

<Prior Art> A conventional mold will be explained based on FIGS. 6 and 7. FIG. 6 is a perspective view of the conventional example, and FIG. 7 is a plan view.

These drawings show the lower mold of the mold, and the reference numeral 20 is a runner;
21 is a gate portion, and 22 is a cavity. The cavity 22 is provided around the runner 20, which is a passage for the resin 25, and communicates with the runner 20 via a gate portion 21 that is perpendicular to the runner 20.

To seal the semiconductor chip with resin, first, the semiconductor chip 24 assembled in the lead frame 23 is placed in each cavity 22 . Then, an upper mold (not shown) that is paired with this mold is placed under pressure on the surface of the mold. After that, the resin 25 is removed from the pot part (not shown).
is poured into the runner 20, passes through the gate portion 21, fills the cavity 22, and hardens, thereby sealing the semiconductor chip 24 within the cavity 22.

<Problems to be Solved by the Invention> In the resin sealing process of the semiconductor chip 24 using such a mold, a large amount of resin 25 is poured into each cavity 22 in order to improve the quality of resin sealing. It is necessary to eliminate the time difference and to make the injection uniform. If there are large variations in the injection timing and injection speed of the resin 25 for each cavity 22, the quality of the resin formed body in each cavity 22 will be non-uniform. In addition, the resin 25, which has a high injection speed, is added to the gold wire that is the bonding wire of the semiconductor chip 24.
If this occurs, the gold wires may come into contact with each other or break.

However, in the mold having the above configuration, as shown in FIG. 7, the resin 25 that has flowed into the runner 20 first flows into the cavity 22 on the front side in the inflow direction (left side in the figure) and fills the inside. Therefore, there was considerable variation in the timing of resin injection into each cavity 22. Furthermore, even after the entire runner 20 is filled with the resin 25, the cavity 2 on the tip side of the runner 20 (on the right side in the figure)
Since the resin 25 is injected into the runner 20, the injection of the resin 25 after the runner 20 is full causes the -fragrance odor cavity 22 to be injected.
, and the injection speed and injection pressure of this cavity 22 tend to be excessive.

For the above reasons, products molded using conventional molds lack uniformity in quality, and the gold wires on the semiconductor chip 24 may come into contact with each other or break.
There was a risk of defective products being produced.

The present invention has been made in view of the above-mentioned problems, and provides a molding die that can uniformize the quality of resin encapsulation of semiconductor chips and prevent the occurrence of defective products such as broken gold wires. The purpose is to provide.

Means for Solving Problems> In order to achieve the above object, the present invention provides a mold in which a plurality of cavities are communicated with a runner through a gate part, and a shutter is provided in the gate part. The mold was configured so that it could be opened and closed freely.

Effects> According to the above configuration, the timing and injection speed of resin injection into each cavity are controlled by opening and closing the shutter provided in the gate portion. Thus, by opening and closing the shutters in conjunction with the flow of resin into the runner, resin can be injected into each cavity simultaneously and at a uniform rate.

<Example> Hereinafter, the present invention will be described in detail based on an example shown in the drawings. FIG. 1 is a perspective view showing an embodiment of the present invention, and FIGS. 2 and 3 are plan views.

These figures show the lower mold of the mold, where l is a runner, 2 is a gate part, and 3 is a cavity.A large number of cavities 3 are provided around the runner l, which is a passage for the resin 4, and the runner 1 and 3 are cavities. It communicates with the runner 1 via the orthogonal gate section 2 . A slit 5a is provided at the end of the gate portion 2 on the runner 1 side.
A shutter 5 is provided in the slit 5a so as to be able to protrude and retract. The shutter 5 opens and closes the gate section 2 by an opening/closing mechanism (for example, a hydraulic mechanism or a motor mechanism, etc.) not shown, and controls the flow of the resin 4 through the gate section 2. Note that this shutter 5 is made of the same material as the mold body, for example, J
Made of tool steel such as IS 5KD-11.

For resin sealing, as shown in FIG. 2, first, a semiconductor chip 7 assembled in a lead frame 6 is placed in each cavity 3. Then, an upper mold (not shown) that is paired with this mold is placed under pressure on the surface of this mold, and each shutter 5 is closed. Thereafter, resin 4 is poured into the runner 1 from a pot portion (not shown). Then, since all the shutters 5 are in a closed state, the resin 4 in the runner l does not flow into each cavity 3, but fills up to the tip of the runner l. When the runner l is filled with resin 4 up to its tip, the third
As shown in the figure, each shutter 5 is opened simultaneously to open the gate section 2. As a result, the resin 4 is injected into each cavity 3 all at once. At this time, since the entire runner 1 is filled with the resin 4, the resin flows into each cavity 3 at the same speed. Therefore, resin is injected into the cavity 3 at the same time and at a uniform rate.

In the above embodiment, the shutter 5 is provided on the runner l side of the gate section 2, but the invention is not limited to this.
As shown in FIG. 5, it is also conceivable to provide the shutter 5 at the end of the gate section 2 on the side of the cavity 3. By doing this, the shutter 5 is closed once more before the resin 4 injected into the cavity 3 hardens, so that it bites into the resin 4 that is in the middle of hardening, and the resin at the boundary between the cavity 3 and the gate part 2 is deeply penetrated. A notch can be formed. This cutout makes it easier to cut the resin-sealed semiconductor chip 7 and the resin 4 of the gate part 2 after the resin 4 has hardened, and also allows a part of the resin 4 of the gate part 2 to be removed from the semiconductor chip. 6. This can prevent the particles from becoming sticky and remaining.

<Effects of the Invention> As described above, according to the present invention, the resin injection timing and injection speed are controlled by the shutter of the gate part.
By appropriately setting the opening and closing timing of the shutter, resin can be injected into each cavity simultaneously and at a uniform speed. Therefore, the quality of the resin sealing in each cavity is made uniform, and the occurrence of defects such as gold wire contact is prevented.

[Brief explanation of the drawing]

1 to 3 relate to one embodiment of the present invention, in which FIG. 1 is a partially enlarged perspective view showing the main parts thereof, and FIGS. 2 and 3 are plan views showing the state in which it is used. 4 and 5 relate to other embodiments, and FIG. 4 is a plan view;
FIG. 5 is a sectional view thereof. FIGS. 6 and 7 relate to a conventional example, with FIG. 6 being a partially enlarged perspective view showing the main parts thereof, and FIG. 7 being a plan view showing its usage state. 1...Runner 2...Gate section 3...Cavity 4...Resin 5...Shutter 7...Semiconductor chip

Claims (1)

[Claims] (1) A mold in which a plurality of cavities are communicated with a runner via a gate portion, wherein the gate portion is provided with a shutter that can be freely opened and closed.