JPH0233509B2 - JUSHIFUSHIGATAHANDOTAISOCHOMOORUDOKANAGATA - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention involves positioning and mounting a lead frame to which semiconductor devices such as ICs and transistors are attached in a bonding process, and injecting resin under pressure into the semiconductor device portion to produce a resin-sealed semiconductor. The present invention relates to a mold die (hereinafter simply referred to as a die) used when molding the device.

1A and 1B are a perspective view and a side view, respectively, showing the outer shape of an example of a resin-sealed IC.

Figure 2 shows the resin-sealed type shown in Figure 1 a and b.
FIG. 3 is a perspective view showing a state in which an IC is molded into a lead frame.

FIG. 3 is a plan view showing a conventional lower mold for molding a resin-sealed IC, and FIG. 4 is a sectional view taken along the - line in FIG. 3.

In these figures, 1 is a lower mold, 2 is a runner processed into the lower mold 1, and 4 is a resin-sealed part of the resin-sealed IC processed into the lower mold 1 and shown in FIG. 3 is a gate machined into the lower mold 1 and guides the resin from the runner 2 to the cavity 4; 5 is a positioning pin, which is a positioning hole machined on the lead frame 14; 14a to correctly position the lead frame 14 on the lower mold 1 and place it on the frame mounting surfaces 6 and 7. 8 is an air vent, which is a shallow groove machined at the end of the runner 2. 9 and 10 are the lower mold 1
Ejector holes 9 and 10 are equipped with ejector pins 1.
1 and 12 are slidably inserted, and after molding is completed, the cavity surface runner etc. are ejected and released from the mold. 12a, 12 in Figure 1 a and b
b, 11a, 11b, 12a, 12b in Fig. 2 are ejector pin marks.

The upper mold has a resin-sealed mold shown in FIG. 1 on the surface of the lower mold 1 facing the cavity 4.
A cavity having the same shape as the upper half of the resin-sealed portion of the IC is formed, and a positioning pin insertion hole into which the positioning pin 5 can be inserted is machined in the surface portion facing the positioning pin 5. Since this is the same as the state without the runner 2, gate 3, and air vent 8, illustration and description of the upper mold will be omitted, and only the lower mold 1 will be described below.

A resin-encapsulated IC is molded using the lower mold 1 and upper mold described above. First, the molding temperature of the resin used, such as a thermosetting resin such as epoxy resin or silicone resin, is lowered. The temperatures of the mold 1 and the upper mold are raised, the lead frame 14 is placed correctly on the lower mold 1, and the lower mold 1 and the upper mold are clamped by a press.

Next, when resin is injected and pressurized from the direction of the bold arrow in FIG. 3, the resin is filled in the runner 2 → gate 3 → cavity 4 in this order. After injecting the resin and applying pressure, wait for the resin to harden before opening the mold. First, the ejector pin provided on the upper mold releases the resin attached to the upper mold, and the lower mold is released at the bottom dead center of the press. 1
The resin part is released from the mold by ejector pins 11 and 12 provided in the molded parts, and a molded product as shown in FIG. 2 is obtained.

In the mold structure according to the above conventional example, when releasing the mold at the bottom dead center of the press, the terminal end face B of the runner 2 (Fig. 4)
Due to the resin adhesion stress between and the ejector pin 11, a bending moment acts between C shown in FIG.
When the runner 2a (Fig. 2) is released from the mold, it may vibrate or
A phenomenon occurred in which the runner 2a remained broken.

In conventional molds for resin-sealed semiconductor devices, due to this vibration phenomenon and the bending phenomenon of the runner 2a, the lead frame 14 may come off the runner 2a and the lead frame 14 may remain in the mold, or the broken runner 2a may fall into the mold. There was something left to do. Therefore, there are drawbacks such as the need to take out the molded product and check whether the runner 2a remains in the mold, and it also becomes a cause of hindering automation of resin sealing work.

The present invention has been made in view of the above-mentioned problems, and provides a mold for a resin-sealed semiconductor device that eliminates the vibration caused by the resin being caught at the end surface of the runner, and eliminates the unbent portion of the resin. The purpose is to do. Below, a mold according to an embodiment of the present invention used for molding the resin-sealed IC shown in FIG. 1 is shown in FIG.
FIG. 6 will be explained.

In this example as well, the upper mold is almost the same as the lower mold as in the conventional example shown in FIGS. 3 and 4, so the explanation of the upper mold will be omitted and only the lower mold will be explained. .

FIG. 5 is a plan view showing the lower mold of this embodiment, and FIG. 6 is a sectional view taken along the - line in FIG. In these figures, 1 to 12 are equivalent to the conventional example described above, and 13 is an end plate for sealing the resin injected from the runner 2 from flowing out from the lower mold 1; The plate 13 is connected to the lower mold 1 by screws (not shown). An air vent 8 is machined into the end plate 13. 15 is processed into the end plate 13 and the end plate 13 on the end face side of the runner 2 so that the resin stuck to the contact surface between the end face of the runner 2 and the end plate 13 can be easily released from the mold after molding. This is the open slope, which is a feature of the present invention.

According to the mold having the above configuration, the generated moment explained in the conventional example can be significantly reduced due to the draft slope 15 formed on the contact surface between the end face of the runner 2 and the end plate 13.

In addition, in the description of this invention, the runner 2 is attached to the lower mold 1.
The same effect can be achieved even if the upper mold is hit by a runner by similarly providing a punching gradient.

As explained in detail above, in this invention, the cutout slope is formed on the end face of the runner of the mold, so that the fixed resin can be easily released from the mold after molding, resulting in work efficiency and time reduction. This has the advantage of improving the operating rate.

[Brief explanation of drawings]

Figures 1a and b are a perspective view and a side view showing an example of the outer shape of a resin-sealed IC, respectively, and Figure 2 is a side view of an example of a resin-sealed IC.
FIG. 3 is a plan view of the lower mold in the conventional example, FIG. 4 is a sectional view taken along the - line in FIG. 3, and FIG. FIG. 5 is a plan view of a lower mold showing an embodiment of the present invention, and FIG. 6 is a sectional view taken along the - line in FIG. 5. In the figure, 1 is the lower mold, 2 is the runner, 3 is the gate,
4 is a cavity, 5 is a positioning pin, 6 and 7 are frame mounting surfaces, 8 is an air vent, 9 and 10 are ejector holes, 11 and 12 are ejector pins, 13 is an end plate, 14 is a lead frame, and 15 is a vent slope. be. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A lead frame on which a semiconductor device is assembled, a runner for positioning and mounting this lead frame and injecting resin into a portion of the semiconductor device,
1. A mold for a resin-sealed semiconductor device, characterized in that a pair of upper and lower molds each have a gate and a cavity, and a recessed slope is formed on the end face of the runner of the mold.