JP2778332B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-sealing mold for a resin-sealed semiconductor device, and more particularly to a resin-sealing mold used for a transfer resin-sealing molding machine.

[0002]

2. Description of the Related Art Conventionally, this type of resin sealing mold is shown in FIG.
As shown in FIG. 1, the structure has a cavity 4 serving as a sealing body of a semiconductor device, a gate 3 for injecting resin into the cavity 4 from a runner, and an air vent 58 for discharging air from the cavity 4. ing.

When the semiconductor device 12 is sealed with resin using the above-described mold, the element 12 is mounted on the element mounting portion of the lead frame 11.
Is mounted and the wire-bonded lead frame 11 is clamped by the upper mold 7 and the lower mold 9, and thereafter,
As shown in FIGS. 13 and 14, a resin 14 is generally injected into the cavity 4 through the gate 3.

[0004]

In the resin-molding mold having the conventional structure described above, when a semi-finished product subjected to wire bonding is resin-sealed, the package size is increased due to the recent increase in the number of pins, the upper cavity thickness and the lower cavity are reduced. Due to the non-uniform thickness, the resin injected into the upper cavity and the lower cavity tended to flow non-uniformly as shown in FIG.

As a result, when the filling rate of the resin into the cavity 4 is increased, the resin flows from the upper cavity to the lower cavity from the gap between the leads as shown in FIG. Although the air vent 58 is not completed, the air vent 58 may be closed by the resin, and the air remaining in the lower cavity opposite the gate is not exhausted from the air vent 58. Therefore, even if the injection pressure is completely applied to the resin, As shown in FIG. 15, air bubbles 15 tend to remain in the resin 14 in the cavity below the gate-facing portion.

Since the bubbles 15 remaining inside the resin 14 have a poor appearance, there is a problem that the yield in the manufacturing process is reduced.

[0007]

The gist of the present invention is that a resin is
The second is provided between the runner to be injected and the cavity.
1 gate and air for discharging air from the cavity
A vent, provided between the air vent and the cavity
Between the resin reservoir and the cavity.
Using a resin sealing mold having a second gate provided in
In the method for manufacturing a semiconductor device,
For holding a lead frame with a semiconductor element mounted on it
And from the runner through the first gate
Injecting resin into the cavity and into the resin reservoir,
Closing the second gate; and
Pressurizing the injected resin to seal the resin.
It is to do.

[0008]

When the semiconductor chip is housed in the cavity, the resin is injected from the first gate with the second gate pin connecting the cavity and the resin reservoir. With the injection of the resin, the air in the cavity is discharged to the resin reservoir. When the resin fills the cavity, the second gate pin blocks the cavity from the resin reservoir.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing an upper mold portion of a first embodiment of the present invention, and FIG. 2 is a diagram showing a bonded lead frame 11 in a cross section taken along line AA 'in FIG. FIG. 3 to FIG. 6 are cross-sectional views showing a tightened state, and FIGS. In FIG. 2, 1 is a main runner, 2 is a sub-runner, 3 is a first gate, 4 is a cavity, 5 is an upper mold second gate opening / closing pin, 6 is an upper resin reservoir, 7 is an upper mold, and 8 is an upper mold. Air vent, 9 is lower mold, 10
Denotes an upper second gate.

FIG. 2 shows a state before the resin injection with the lead frame 11 clamped in the encapsulating mold according to the first embodiment of the present invention, wherein the second gate opening / closing pin 5 is raised,
Gate 10 is open.

FIGS. 3 to 5 show a state in which the resin is injected into the cavity 4 and the resin reservoir 6 in the state shown in FIG. 2, and the air pressed to the tip of the resin in the cavity 4 is a conventional air vent. 58, it is not possible to discharge all of them. However, in the mold of this embodiment, as shown in FIG. Is discharged.

When the state shown in FIG. 5 is reached in which all the air located at the tip of the resin in the cavity 4 is discharged into the resin reservoir 6, the second gate opening / closing pin 5 is lowered as shown in FIG. Then, the second gate 10 is shut off and pressurized until the injection pressure reaches a set value, whereby the resin can be sealed without leaving air bubbles in the cavity 4.

Further, since the resin reservoir 6 is separated by the cavity 4 and the second gate opening / closing pin 5 during the resin injection process, even if the volume of the resin reservoir 6 is relatively large, the shape of the package after molding can be reduced. There is no loss.

FIG. 7 is a sectional view showing a state in which the bonded lead frame 11 is clamped by using the encapsulating mold according to the second embodiment of the present invention, and FIGS. 8 to 11 show the state of resin injection. .

FIG. 7 shows a state before the resin injection with the lead frame 11 clamped in the encapsulating mold according to the second embodiment of the present invention. 5 and 16 are open up and down respectively, and the second gate 1
Reference numerals 0 and 17 are open.

In the state shown in FIG. 7, when the lead frame 11 has a narrow lead interval due to the recent increase in the number of pins, the lead gap becomes narrow. The resin flow in the direction is reduced. Therefore, as shown in FIGS. 8 to 10, the flow of the resin in the cavities 4 of the upper and lower dies 7, 9 is similar to the state in which the upper and lower cavities are separated and the resin flows. As shown in FIG. 10, in the second embodiment, the upper and lower molds 7 and 9 are provided with the resin reservoirs 6 and 18, respectively. As shown, upper and lower mold 7,
9 can be completely discharged to the resin reservoirs 6 and 18.

When the state shown in FIG. 10 is reached in which all the air located at the tip of the resin in the cavity is discharged into the resin reservoirs 6 and 18, as shown in FIG. By moving 16 to shut off the second gates 10 and 17 and applying pressure until the injection pressure reaches the set pressure, resin sealing can be performed without leaving bubbles in the cavity 4.

[0019]

As described above, the present invention has a resin reservoir formed continuously in a cavity, and can be opened and closed by a second gate pin when resin is injected from the cavity into the resin reservoir. All the air located at the tip of the resin in the cavity is discharged into the resin reservoir and then pressurized to the set injection pressure, so that the resin can be sealed without leaving any bubbles in the cavity, resulting in poor appearance. Can be reduced. The resin reservoir formed continuously in the cavity is separated into the cavity and the resin reservoir by the second gate pin during the resin sealing, so that the shape of the package after the resin sealing is not impaired. The size of the resin reservoir can be arbitrarily increased.

In the first embodiment, since the resin reservoir and the gate opening / closing pins need to be provided only in the upper mold, the mold can be easily manufactured. Further, in the second embodiment, since the upper and lower molds have resin reservoirs, the distance between the internal leads is small, so that the resin does not easily flow in the vertical direction from the gap between the leads, and the resin flows in the upper and lower cavities are separated from each other. In this case, the air at the tip of each resin in the upper and lower cavities is discharged to the resin reservoirs arranged vertically. As a result, void defects can be reduced even in a package having a narrow lead interval. Also actually 160p
A comparison of the void defect occurrence rate between the sealing mold of the present invention and the mold having the conventional structure in QFP showed the following results, and proved to be effective.

[0021]

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment.

FIG. 2 is a sectional view taken along the line A-A 'of FIG.

FIG. 3 is a sectional view showing a resin injection state of the first embodiment.

FIG. 4 is a sectional view showing another resin injection state of the first embodiment.

FIG. 5 is a sectional view showing still another resin injection state of the first embodiment.

FIG. 6 is a cross-sectional view showing a completed state of resin injection according to the first embodiment.

FIG. 7 is a sectional view showing a second embodiment.

FIG. 8 is a sectional view showing a resin injection state of a second embodiment.

FIG. 9 is a sectional view showing another resin injection state of the second embodiment.

FIG. 10 is a sectional view showing still another resin injection state of the second embodiment.

FIG. 11 is a cross-sectional view showing a completed state of resin injection according to the second embodiment.

FIG. 12 is a sectional view of a conventional example.

FIG. 13 is a cross-sectional view showing a conventional resin injection state.

FIG. 14 is a cross-sectional view showing another resin injection state of the conventional example.

FIG. 15 is a cross-sectional view showing a state of completion of resin injection according to a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Main runner 2 Sub runner 3 First gate 4 Cavity 5 Upper die second gate opening / closing pin 6 Upper die reservoir 7 Upper die 8, 58 Air vent 9 Lower die 10 Upper second gate 11 Lead frame 12 Element 13 Wire 14 Resin 15 Bubble 16 Lower second gate opening / closing pin 17 Lower second gate 18 Lower resin reservoir

Claims (1)

(57) [Claims] 1. A runner and a cavity into which a resin is injected.
And a first gate provided between
An air vent for discharging air, and the air vent and the key.
And a resin reservoir provided between the cavity and the cavity.
A second gate provided between the cavity and the cavity.
Method of Manufacturing Semiconductor Device Using Resin Sealing Die
A lead having a semiconductor element mounted in the cavity.
Holding a frame; and
Through the gate in the cavity and the resin reservoir
A step of injecting fat and a step of closing the second gate
Pressurizing the resin injected into the cavity,
And a resin sealing step .