JPH06216178A - Molding die for resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To block the turning intrusion of resin at the outer surface through a gate sufficiently as the preventing countermeasure against the occurrence of the burr of the resin attached to the outer surface of a lead frame with regard to a molding die for forming the package of a resin sealed semiconductor device so as to hold the lead frame between a lower die and an upper die. CONSTITUTION:A wall surface 2a faces an outer side surface 21a of a lead frame 21, which is mounted on a cavity forming surface 7. A protruding part 13 is provided in the vicinity of a gate 5 of a lower die 2. The protruding part 13 is made to extend into the local region of the outer surface part of the lead frame 21 from the side wall 2a and made to protrude from the cavity forming surface 7. The protruding part 13 crushes the local region to the thin form by closing with an upper die 1. A protruding part 21b, which is locally formed at the outer shape of the lead frame by the crushing, narrows a part of a gap (g) between the outer side surface 21a and the side wall 2a. The turning intrusion of the resin into the outer surface of the lead frame 21 from the gate 5 is blocked when the resin is injected in the halfway in this constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-molded semiconductor device molding die for forming a package of a resin-molded semiconductor device by sandwiching a lead frame between a lower mold and an upper mold.

In the above resin-sealed semiconductor device, a semiconductor chip is mounted on the inner lead side of a lead frame having an inner lead and an outer lead, and the semiconductor chip is resin-sealed together with the inner lead by resin molding using the molding die. Package is formed, and unnecessary parts of the lead frame are cut and other post-processing is performed to complete the process.

In this resin molding, it is desirable to prevent unnecessary resin burrs from adhering to the outer periphery of the lead frame, and at least to prevent the adhesion of resin burrs that are difficult to remove. Therefore, necessary measures are taken for the mold. The present invention is a device related to that measure.

[0004]

2. Description of the Related Art FIG. 4 is a perspective view for explaining a molding die for a resin-sealed semiconductor device described above, and FIG. 5 is a plan view (a) of a lead frame and a plan view (b) when a package is formed. Is.

In FIG. 4, the molding die and the resin molding using the same are as follows. That is, 1 is the upper mold,
Reference numeral 2 denotes a lower mold. The lead frame 21 as shown in FIG. 5A is placed on the cavity forming surface 7 of the lower mold 2 (the surface in which the six cavities 6 are engraved in a line in the figure). The lead frame 21 is sandwiched from both sides by mold clamping in which the mold 1 and the lower mold 2 are butted against each other, the preheated resin tablet 15 is put into the pot 14 of the upper mold 1, and pressure is applied to the resin tablet 15 by the plunger 16. The resin of the tablet 15 is injected into the individual cavities 6 through the center cull 3 → runner 4 → gate 5 to form the package 25 of the resin-sealed semiconductor device as shown in FIG. 5B.

The lead frame 21 includes internal leads 22,
Since the semiconductor chip is fixed to the die stage 24 in advance and connected to the internal lead 22 (not shown), the package 25 includes the external lead 23 and the die stage 24. Is sealed with resin.

In order to facilitate manufacturing and maintenance, the above-mentioned molding die has a form in which the center block 8 and the chase block 9 shown in FIG. The center half 3 and the first half of the runner 4 are arranged, the second half of the runner 4 is arranged in the chase block 9, and the cavity blocks 10 whose upper surfaces serve as the cavity forming surfaces 7 are incorporated on both sides thereof. The gate 5 extends from the runner 4 of the chase block 9 to the cavity 6 of the cavity block 10.

Like the lower mold 2, the upper mold 1 has a form in which a center block and a chase block are incorporated, and a cavity is provided in the cavity block so that the pot 14 is located above the center cull 3 and forms a pair with the cavity 6. The runner and gate are generally omitted depending on the lower mold 2.

By the way, since the lead frame 21 is carried in and out of the lower die 2, the lower die 2 is slightly (for example, 0.
A gap of about 05 mm) is formed, and the gate 5 crosses the gap. For this reason, in resin molding, when the resin is injected into the cavity 6, the resin also wraps around the gap from the middle of the gate 5,
As shown in FIG. 5B, a required package 25 is formed on the lead frame 21, and unnecessary resin burrs 26 and 27 are attached to the outer periphery thereof.

The resin burr 26 adheres to the flat outer surface of the side portion of the lead frame 21 and can be easily removed after the fact. However, the resin burr 27 wraps around the end portion of the lead frame 21. Since it adheres to the external leads 23, it is extremely difficult to prevent the external leads 23 from being deformed during subsequent removal. In particular, in the case where the cavity forming surface 7 is provided with a recess in the outer lead 23 for stabilizing the mold clamping, the resin burr 27 also wraps around the surface of the outer lead 23 and is thus almost impossible to remove. .
Therefore, it is necessary to take measures to prevent the resin burr 27 from adhering to the mold.

The above-mentioned measures of the conventional example of the molding die described above are shown in FIGS. 6 and 7. FIG. 6 is a perspective view of a chase block in a lower die of a conventional example, and FIG. 7 is a perspective view (a) and a partially enlarged perspective view (b) of a cavity block in a lower die of the conventional example. Resin burr 27 at the boundary between 9 and the cavity block 10.
A resin rotation-stop block 11 is arranged in a portion to be the gap around which the resin is blocked so that a part of the gap is narrowed (for example, about 0.05 mm).

As a result, even if the resin that is about to become the resin burr 27 slightly bleeds from the position of the resin rotation-stop block 11 to the end portion side of the lead frame 21, it does not come around to the portion where the external leads 23 are lined up. As a result, the resin burr 27 does not become the resin burr 27 and is similar to the resin burr 26 and is easily removed.

The size of the gap narrowed by the resin rotation preventing block 11 is ideally set to 0, but the resin rotation preventing block 11 projects from the cavity forming surface 7 by the thickness of the lead frame 21. Therefore, in order to prevent the lead frame 21 placed on the cavity forming surface 7 from overlapping with the resin rotation-stop block 11, it is necessary to make it at least about 0.01 mm or more.

[0014]

However, in recent years, the development of new type resins has progressed, and as a result, the resin with extremely good flowability and the flow at the time of injection, which requires a significantly high resin filling pressure, are larger than before. The resin that becomes becomes available. If such a resin is used, the above-mentioned function of the resin rotation-stop block 11 becomes insufficient, and the resin burr 27 may be generated. In that case, it is necessary to more strongly prevent the resin from flowing from the gate 5 around the outer periphery of the lead frame 21.

The present invention relates to a resin-molded semiconductor device molding die for forming a package of a resin-molded semiconductor device by sandwiching a lead frame between a lower mold and an upper mold. The purpose of the present invention is to reliably prevent the resin from wrapping around.

[0016]

1A and 1B are explanatory views of the principle of the present invention. FIG. 1A is a partial plan view of a lower mold, and FIG.
-A sectional drawing, (c) is BB sectional drawing similarly.

In order to achieve the above-mentioned object, the resin-molded semiconductor device molding die according to the present invention is provided with a lead frame 21 on the cavity forming surface 7 of the lower die 2 with reference to FIG.
The lead frame 21 by mounting the
Is a mold die for forming a package of the resin-sealed semiconductor device on the lead frame 21 by injecting resin into the cavity 6 through the gate 5 provided on the surface of the lower mold 2 with the lower mold 2 In the vicinity of the gate 5 of the lead frame 21 extending from the wall surface 2a facing the outer surface 21a of the lead frame 21 to the local area of the outer peripheral portion of the lead frame 21 and projecting from the cavity forming surface 7 by the mold clamping. Has a convex portion 13 that crushes the region thinly,
The protruding portion 21b locally generated on the outer shape of the lead frame 21 by the squeezing narrows a part of the gap g between the outer surface 21a and the wall surface 2a, and the resin gate 5 to the lead frame 21 at the time of the injection. The feature is that it is prevented from wrapping around the outer circumference.

It is desirable that the vicinity of the gate 5 having the convex portion 13 is a portion for preventing resin from wrapping around to the end portion of the lead frame 21 where the external leads are lined up. It is desirable that the convex portion 13 disposed on the cavity block is formed by a resin rotation stop block that is removable from the cavity block.

[0019]

As described above, since the lead frame 21 is placed on the cavity forming surface 7, the wall surface 2a of the lower mold 2 is used.
Must be arranged such that a gap of, for example, about 0.05 mm is formed between the mounted lead frame 21 and the outer side surface 21a. Since the limit is about 0.01 mm even if it is narrowed, the conventional mold die cannot sufficiently prevent the above-mentioned wraparound when a new type resin having a good resin flow at the time of injection is used.

On the other hand, in the molding die of the present invention,
Since the projecting portion 21a is formed on the lead frame 21 in the mold clamping after the lead frame 21 is placed, and a part of the gap g with respect to the wall surface 2a is narrowed thereby, the placement of the lead frame 21 is not hindered. However, it is possible to reliably prevent the resin from flowing around from the gate 5 on the outer periphery of the lead frame 21.

Then, the convex portion 13 forming the protruding portion 21a
Is disposed in the vicinity of the gate 5 that prevents the resin from wrapping around the end of the lead frame 21 where the external leads are lined up, the resin burr 27 described above can be suppressed from being generated, and the resin that is difficult to remove afterwards. It is possible to prevent the adhesion of burrs. Needless to say, if the convex portions 13 are arranged on both sides of each gate 5, the resin burr 27 and the resin burr 2 described above will be used.
6 can be suppressed.

Further, the molding die has a cavity 6
Is arranged in the cavity block, and the convex portion 13 is formed in the cavity block by the removable resin blocking block, which facilitates manufacturing and maintenance.

[0023]

Embodiments of the present invention will be described below with reference to FIGS. 2 is a perspective view of the chase block in the lower mold of the embodiment, and FIG. 3 is a perspective view (a) and a partially enlarged perspective view (b) of the cavity block in the lower mold of the embodiment. Indicates the same object.

This embodiment has the form of FIG. 4 described above, and as a measure for preventing the adhesion of the resin burr 27 described above, the conventional resin whirl-stop block 11 is shown in FIG. 2 and FIG. The resin rotation stop block 12 shown in FIG.

That is, in FIG. 2 and FIG. 3, the resin whirl-stop block 12 is specifically a cavity block 10 at a portion in contact with the chase block 9 where a gap for letting the resin burr 27 around is formed, specifically, the cavity block. The convex portion 1 described above with reference to FIG. 1 is arranged at the corner (end face side) of 10 and a part of the upper end portion projects from the cavity forming face 7.
3 and a wall surface 2a continuous with the wall surface 3 are formed.

The height of the wall surface 2a as viewed from the cavity forming surface 7 substantially matches the thickness of the lead frame 21,
The gap g between the mounted lead frame 21 and the outer surface 21a is set to about 0.01 mm, and the convex portion 1
3, the height h is about 3 of the thickness of the lead frame 21.
At 5%, the depth toward the lead frame 21 side is about 1 mm. The width of the resin rotation-stop block 12 is about 10 mm for easy handling, but the widths of the wall surface 2a and the protrusion 13 are about 3 mm from the corner of the cavity block 10.
mm.

In the embodiment in which the resin rotation preventing block 12 is arranged, as described with reference to FIG. 1, the convex portion 13 crushes the local area of the outer peripheral portion of the lead frame 21 at the time of mold clamping, so that Since the gap g of about 0.01 mm is narrowed to about 0 mm, the resin burr 27 which does not hinder the placement of the lead frame 21 and is difficult to remove afterwards even if a resin having a good flow at the time of injection is used. Can be suppressed.

The resin detent block 12 is detachably attached to the cavity block 10.
As a result, the mold of the embodiment is easy to manufacture and maintain.

The above-described dimensions of the resin rotation-stop block 12 may be appropriately determined depending on the situation.
Further, the position where the resin rotation-stop block 12 is arranged may be adjacent to the gate, if possible, instead of the above-mentioned end surface of the cavity block 10. Furthermore, by disposing resin blocking blocks similar to the resin locking block 12 on both sides of each gate 5, the resin burr 26 described above can also be suppressed.

[0030]

As described above, the present invention relates to a resin-molded semiconductor device molding die for forming a package of a resin-molded semiconductor device by sandwiching a lead frame between a lower mold and an upper mold. It is possible to sufficiently prevent the resin from wrapping around from the gate on the outer periphery of the lead frame, and even when using a resin that has a good flow at the time of injection, the resin burr that adheres to the outer periphery of the lead frame due to the wraparound There is an effect that the generation is appropriately suppressed and the lead frame is prevented from being deformed by the removal of the resin burr which is performed later.

[Brief description of drawings]

FIG. 1 is an explanatory view of the principle of the present invention.

FIG. 2 is a perspective view of a chase block in the lower mold of the embodiment.

FIG. 3 is a perspective view and a partially enlarged perspective view of a cavity block in the lower mold of the embodiment.

FIG. 4 is a perspective view for explaining a molding die for a resin-sealed semiconductor device.

FIG. 5 is a plan view of the lead frame and a plan view of the package formation.

FIG. 6 is a perspective view of a chase block in a lower mold of a conventional example.

FIG. 7 is a perspective view and a partially enlarged perspective view of a cavity block in a lower mold of a conventional example.

[Explanation of symbols]

 1 Upper Mold 2 Lower Mold 2a Lower Mold Wall 3 Center Cull 4 Runner 5 Gate 6 Cavity 7 Cavity Forming Surface 8 Center Block 9 Chase Block 10 Cavity Block 11, 12 Resin Rotation Block 13 Convex 14 Pot 15 Resin Tablet 16 Plan Jar 21 Lead frame 21a Outer surface of lead frame 21b Projection 22 Internal lead 23 External lead 24 Die stage 25 Package 26, 27 Resin burr g Gap between outer surface of lead frame and lower mold wall h Convex height

Claims (3)

[Claims] 1. A lead frame (21) is placed on a cavity (6) forming surface (7) of a lower mold (2), and an upper mold (1) is mounted on the lead frame (21).
The lead frame (21) is sandwiched from both sides by mold clamping with and resin is injected into the cavity (6) through the gate (5) provided on the surface of the lower mold (2),
A molding die for forming a package of a resin-sealed semiconductor device on the lead frame (21), wherein the lead frame (21) is placed near the gate (5) of the lower die (2). It extends from the wall surface (2a) facing the outer side surface (21a) to the local area of the outer peripheral portion of the lead frame (21) and projects from the cavity forming surface (7), and the local area is pressed thinly by the mold clamping. A protrusion (21b) having a crushing convex portion (13) locally generated on the outer shape of the lead frame (21) by the crushing is formed on the outer surface (21).
Part of the gap (g) between a) and the wall surface (2a) is narrowed to prevent the resin from wrapping around the lead frame (21) from the gate (5) during the injection. A mold die for a resin-sealed semiconductor device, which is characterized in that 2. The vicinity of the gate (5) having the convex portion (13) is a portion for preventing resin from wrapping around to an end portion of the lead frame (21) where the external leads are arranged. The mold for a resin-sealed semiconductor device according to claim 1. 3. In the lower mold (2), the cavity (6) is arranged in a cavity block, and the projection (1) is formed.
3. The mold for a resin-sealed semiconductor device according to claim 1 or 2, wherein 3) is formed by a resin blocking block which can be removed from the cavity block.