JP2532490B2 - Method for manufacturing resin-sealed semiconductor device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a resin-sealed semiconductor device,
In particular, the present invention relates to a method for efficiently removing a thin layer of resin (usually called a burr) when the resin is sealed without forcibly suppressing the generation of the thin layer.

2. Description of the Related Art FIGS. 4 and 5 show a conventional method for manufacturing a resin-sealed semiconductor device.

In FIGS. 4 and 5, 1 and 2 are upper and lower molds, 3 is a cavity formed between these molds 1 and 2, and 4 is a lead frame sandwiched between the molds 1 and 2. , 4a are a plurality of lead portions 4b formed in the lead frame 4 in a comb shape.
A tie bar 5 connecting the two is a semiconductor chip welded onto the lead frame 4 located in the cavity 3.

In the above structure, when the lead frame 4 is sandwiched between the upper and lower molds 1 and the molten resin is injected into the cavity 3 in this state, the resin is filled in the cavity 3. After the resin is cooled and solidified, the lead frame 4 is taken out from the molds 1 and 2, and a package 6 for protecting the chip 5 is formed as shown in FIG.

Problems to be Solved by the Invention However, when the molten resin is injected, the resin also flows into the thin gap between the molds 1 and 2 and the lead frame 4. For this reason,
When the lead frame 4 is removed from the molds 1 and 2 after cooling and solidification,
As shown in FIG. 5, a thin layer 7 of resin called a burr is attached to the surfaces of the leads 4b and the tie bars 4a of the lead frame 4. For this reason, it is necessary to remove the thin layer 7 in a later step, and there is a problem that the number of additional work steps increases. Particularly, in the conventional example shown in FIGS. 4 and 5, since the thin layer 7 reaches a position beyond the tie bar 4a, the work of removing the thin layer 7 becomes very complicated.

On the other hand, in order to suppress the generation of such a thin layer 7, it is necessary to make the precision of the mold extremely high, and there is a drawback that the facility cost of the mold and the like becomes expensive.

It is an object of the present invention to provide a method of manufacturing a resin-sealed semiconductor device that solves such conventional problems.

Means for Solving the Problems In order to achieve this object, the present invention forms two protrusions on a mold, and these protrusions are provided in the vicinity of the tie bar of the lead frame and the portion where the resin sealing body is to be formed. The resin flow that flows out from the gap between the upper and lower molds that are abutted by being pressed against each of the lead frames is blocked near the tie bars. The thin layer of resin adhering to the lead surface is peeled off.

Function In this way, the thin layer can be removed without requiring expensive equipment and without requiring a special step for removing the thin layer.

Embodiment FIG. 1 to FIG. 3 are explanatory views in the order of steps of an embodiment of the present invention, and in each drawing, parts having substantially the same functions as those of the conventional example of FIG. 4 and FIG. The description is omitted by giving the reference numerals and omitting the description, focusing on the part different from the conventional example. As shown in FIG. 1, the lower surface of the upper die 1 has a width of about 0.2 mm.
The second protrusions 1a and 1b are provided, the first protrusion 1a is pressed against the end of the tie bar 4a, and the second protrusion 1b is pressed against the surface of the lead frame 4 in the immediate vicinity of the cavity 3. To be

When molten resin is injected into the cavity 3 in this state, the package 6 which is a resin sealing body that protects the semiconductor chip 5 is formed by the resin filled in the cavity 3. At this time, part of the molten resin enters the gap between the mold 1 and the lead frame 4. The first and second protrusions 1a and 1b are tie bars 4a
There is a case where it is pressed against the end of the mold and the vicinity of the cavity 3 and a part of it bites into the lead frame 4, but it completely bites due to the relationship between the precision of the mold and the capability of the manufacturing machine that are normally used. is not. Therefore, the resin penetrates not only between the cavity 3 and the second protrusion 1b but also between the first protrusion 1a and the second protrusion 1b to form a thin layer. However, this thin layer does not leak out from the protrusion 1a, and is almost shielded from the package 6 by the protrusion 1b. That is, when the lead frame 4 is taken out from the molds 1 and 2 after the resin is cooled and solidified, the first and second protrusions 1a and 1b are formed on the leads 4b as shown in FIG.
The two types of thin layers 7a and 7b that are blocked by this will remain. After the package 6 is formed as described above, the tie bar 4a is punched out and each lead is further removed.
4b is bent as shown in FIGS.

When the lead 4b is bent during this bending process, the thin layer 7a separated from the package 6 is naturally peeled off as shown in FIG. 3b according to the bending of the lead 4b. In this way, the thin layer 7a is removed without any special steps.

 The protrusions 1a and 1b may be provided on both upper and lower molds.

EFFECTS OF THE INVENTION As described above, according to the present invention, a thin resin layer (burr) can be easily formed at the time of forming a package without requiring a special process and without requiring an expensive mold or equipment. It can be reliably removed.

[Brief description of drawings]

FIG. 1 is a sectional view of a mold part used in one embodiment of the present invention,
2 is a perspective view of a main part of the lead frame obtained in the same embodiment, and FIGS. 3a, 3b, 3c are side views in order of steps for explaining the lead bending process of the same embodiment, FIG. FIG. 5 is a cross-sectional view and a perspective view of a main part of a conventional example. 1 ... Upper mold, 2 ... Lower mold, 2a ... First protrusion, 2b ...
... second protrusion, 3 ... cavity, 4 ... lead frame,
4a ... tie bar, 4b ... lead, 5 ... semiconductor chip,
6 ... Package, 7, 7a, 7b ... Thin layer.

Claims (1)

(57) [Claims] 1. A lead frame is arranged so that a semiconductor chip is positioned in a cavity formed by a pair of upper and lower molds, and first and second protrusions formed on the mold are used as tie bars of the lead frame. Pressing in the vicinity of the cavity,
The lead frame is sandwiched, resin is injected into the cavity to form a resin sealing body, and a thin layer of resin remaining on the lead frame located between the first and second protrusions is bent into a lead. A method for manufacturing a resin-encapsulated semiconductor device, which comprises peeling and removing by processing.