JPH04359436A - Mold for forming resin sealed type semiconductor device - Google Patents

Abstract

PURPOSE:To make it possible to fill the whole cavities in a mold for the formation of a resin seal type semiconductor device simultaneously. CONSTITUTION:The depth 9a of a sub-runner 9 which connects a gate 5 of a cavity 4 with a runner 3 is increased as the cavity 4 is separated from an injection point which supplies resin to a mold.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for molding a resin-sealed semiconductor device for sealing a semiconductor pellet.

0002

2. Description of the Related Art FIG. 3 is a plan view schematically showing a conventional resin-sealed semiconductor device molding die (hereinafter referred to as the molding die), and FIG. 4 is a cross-sectional view taken along the line IV--IV in FIG. It is. In these figures, an upper die 1 is provided with a gate 5 that connects a runner 3 and a cavity 4. The gate 5 has a gate width 6, a gate depth 7, an incident angle α, and a sub-runner depth 9a. Resin enters each cavity through this gate 5. The lead frame 10 with the assembled semiconductor pellets is placed on the lower mold 2, and after the upper and lower molds are brought together and tightened, resin is supplied from the injection point 11 in the direction of the arrow to seal the semiconductor pellets. It looks like this.

The resin from the runner 3 is injected into the cavity 4 through the gate 5, but the gate width 6, gate depth 7, incident angle α, and sub-runner depth 9a are the same for all cavities. Therefore, the further the injection point 11 is, the longer it takes to inject into the cavity 4 than the closer it is, and since the mold uses a thermosetting resin, the inflow speed also changes.

In view of this, there is a method in which the gate width 6, gate depth 7, and incident angle α are changed so that all cavities are filled at the same time, and as another conventional technique, a sub-runner 9 is used as shown in FIG. One in which the angle θ with respect to the runner 3 is sequentially changed (see Utility Model Application No. 196009/1983), or one in which the length of the sub-runner is shortened as it gets farther from the injection point 11 as shown in FIG. 157
No. 932), however, there were problems with gate breakability (product releasability) and difficulty in manufacturing the mold.

[0005]

[Problems to be Solved by the Invention] Particularly, the conventional molds shown in FIGS. 3 and 4 have good gate break properties, but the resin remains in the cavity where filling is completed early, so the filling of the entire mold is completed. However, the gate part solidifies before the final injection pressure is applied, and the pressure does not propagate into the cavity, making it impossible to collapse the air bubbles remaining in the cavity (void defect), and the same occurs in cavities located downstream. As the number of cavities filled at any given time gradually decreases, the flow rate of the resin flowing inside the cavities increases. In addition, as the viscosity of the resin increases as the curing reaction progresses, the gold wire receives a large drag force and deforms (defective gold wire deformation).

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a mold that is easy to manufacture and does not cause void defects or wire deformation defects.

[0007]

[Means for Solving the Problems] The molding die according to the present invention increases the depth of the sub-runner in each cavity as the distance from the resin injection point increases, thereby simultaneously filling all cavities and filling the inside of the cavity. The injection time and injection rate are kept constant.

[0008]

[Operation] In the mold according to the present invention, all the cavities are filled at the same time, so that the injection time and injection speed into the cavity are constant, and void defects and gold wire deformation defects do not occur. Furthermore, since the gate width, gate depth, and incidence angle are not changed, processing is easy and gate breakability can be maximized.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Figure 1 is a plan view showing the gate section, and Figure 2 is II of Figure 1.
It is a sectional view taken along the line -II. The upper mold 1 has a gate width 6 connecting the runner 3 and the cavity 4, a gate depth 7, an incident angle α,
A gate 5 consisting of a sub-runner 9 is provided, and the depth 9a of the sub-runner for each cavity increases as it becomes farther from the resin injection point, such as 9a'.

The resin from the runner 3 passes through the gate 5 and is injected into the cavity 4. In order to increase the depth 9a of the sub-runner in each cavity as the distance from the resin injection point increases, Regardless of the distance from point 11, the injection time and injection rate into the cavities 4 can be constant, and all cavities are filled at the same time.

[0011]

As described above, according to the present invention, since all the cavities are filled at the same time, the injection pressure is uniformly applied to all the cavities, and the air bubbles remaining in the cavities can be crushed. and to fill all cavities at the same time,
The flow rate of the resin flowing inside the cavity is kept constant, and even if the viscosity of the resin increases as the curing reaction progresses, the gold wire will not experience a large drag force. Further, since the gate width 6 and the incident angle α are not changed, the gate breakability can be set to the best value, and mass production is good.

[Brief explanation of drawings]

FIG. 1 is a plan view schematically showing an embodiment of a mold for molding a resin-sealed semiconductor device of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG. 1;

FIG. 3 is a plan view schematically showing a conventional mold for molding a resin-sealed semiconductor device.

FIG. 4 is a sectional view taken along line IV-IV in FIG. 3;

FIG. 5 is a plan view schematically showing another conventional resin-sealed semiconductor device molding die.

FIG. 6 is a plan view schematically showing another conventional mold for molding a resin-sealed semiconductor device.

[Explanation of symbols]

1 Upper mold 2 Lower mold 3 Runner 4 Cavity 5 Gate 6 Gate width 7 Gate depth 9 Subrunner 9a Sub-runner depth 10 Lead frame 11 Injection point

Claims (1)

[Claims] Claim 1: Consisting of an upper mold and a lower mold, a lead frame on which semiconductor pellets are assembled is placed on the lower mold,
In a mold for resin sealing of a semiconductor device, in which the upper mold and the lower mold are combined and tightened, resin is injected to seal the semiconductor pellet, between the runner and the gate of the path for feeding the resin into each cavity. A sub-runner part is provided on the
A resin-sealed type characterized in that by increasing the depth of the sub-runner as the distance from the resin injection point increases, each cavity can be filled with resin at the same time, eliminating gold wire deformation defects and void defects. Mold for molding semiconductor devices.