JPH04368138A - Manufacture of resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To make cutting and eliminating tie bars unnecessary, and obtain a stable lead form, by using a lead frame without tie bars, and forming resin in gaps between a plurality of adjacent leads of said lead frame before it is resin sealed. CONSTITUTION:A semiconductor element is mounted on the element mounting part of a lead frame 10, and resin 4 is formed in gaps between a plurality of adjacent leads 2 after the element and lead tips are connected by using metal thin wires. Clamping is performed by using a resin seal metal mold, and resin sealing is performed by injecting sealing resin in the metal mold. Outer leads are subjected to sheathing process like solder plating, and formed in a specified shape. For forming the resin 4 in the gaps between a plurality of the adjacent leads 2 of the lead frame 10, thermosetting resin in a liquid state is dipped in the gaps between a plurality of the adjacent leads 2 of the lead frame 10, and cured by heated. Thereby an expensive press metal mold for cutting and eliminating tie bars is mode unnecessary, and a stable lead form can be obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a resin-sealed semiconductor device.

0002

2. Description of the Related Art Conventionally, resin-sealed semiconductor devices have been assembled according to the process diagram shown in FIG. First, in step S1, a semiconductor element is mounted on the element mounting part 1 of the lead frame 10 as shown in FIG. By sealing the lead frame 10 with a resin and clamping it with a mold, and injecting a sealing resin into the mold, the semiconductor elements, thin metal wires, internal leads, etc. mounted on the element mounting section 1 are sealed with the resin. Manufactured.

In this case, in the periphery of the mold formed in the upper and lower molds of the resin sealing mold, the resin filled into the gaps between the adjacent leads surrounds the mold at a predetermined interval. Generally, the lead is blocked by a tie bar 3 that connects a plurality of leads.

[0004] Thereafter, the tie bars are cut and removed in step S4a, the external leads are subjected to exterior treatment such as solder plating in step S5, and the external leads are formed into a predetermined shape in step S6, thereby completing the semiconductor device.

[0005]

In the conventional manufacturing method described above, the tie bars 3 connecting the plurality of leads must be cut and removed after resin sealing. This tie bar 3
is usually cut and removed using a mold, but a dedicated mold must be manufactured for each different shape of the semiconductor device, which poses a problem in that it costs a lot of money.

Furthermore, as the pitch of the external leads has become smaller, it has become more difficult to manufacture molds, and various problems have arisen. For example, if the pitch of external leads 2 is 0.4 mm,
If the width is 0.2 mm, the thickness at the tip of the cutting blade is only 0.4-0.2=0.2 mm at maximum. Since the cutting edge of such a thin cutting blade is easily damaged by loads such as dust clogging, there is a problem in that maintenance is time-consuming.

[0007] Furthermore, when the tie bar is cut and removed using a mold, the positioning of the lead frame 10 is usually done by inserting a positioning pin provided in the mold into a positioning hole provided in the lead frame. However, some positional deviation occurs due to errors in the manufacturing of the lead frame and mold. In the case of semiconductor devices with a small external lead pitch, even a slight misalignment
There is a problem that the cutting punch gets stuck in the lead, reducing the yield.

The purpose of the present invention is to solve these problems and
It is an object of the present invention to provide a method for manufacturing a resin-sealed semiconductor device, which eliminates the need to cut and remove tie bars, provides a stable lead shape, and improves quality.

[0009]

[Means for Solving the Problems] The structure of the method for manufacturing a resin-sealed semiconductor device of the present invention is such that a tie bar is not provided in a portion located at the root of an external lead in a gap between a plurality of adjacent leads of a lead frame in which a tie bar is not provided. A step of forming an insulator such as a resin, a step of clamping the lead frame with a resin sealing mold and sealing it with resin, and a step of cutting the lead frame and molding the external lead into a predetermined shape. It is characterized by having.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partial plan view of a lead frame illustrating an embodiment of the present invention, and FIG. 2 is a process diagram of this embodiment.

In this embodiment, according to the process diagram shown in FIG. 2, first, in step S1, a semiconductor device is mounted on the device mounting portion 1 of the lead frame 10, and then, in step S2, the device and the tip of the lead are bonded with metal. After connecting with thin wires, resin 4 is formed in the gaps between the adjacent leads 2 in step S3 (FIG. 1(b)), and the mold is clamped with a resin sealing mold in step S4, and the sealing resin is filled in the mold. The semiconductor device is manufactured by resin-sealing the semiconductor device by injecting it with a resin, then performing an exterior treatment such as solder plating on the external leads in step S5, and molding the external leads into a predetermined shape in step S6.

In this embodiment, a lead frame 10 without tie bars shown in FIG. 1(a) is used. In order to form a resin in the gaps between a plurality of adjacent leads, liquid thermosetting resin may be dropped into the gaps between a plurality of adjacent leads 2 of the lead frame 10 in FIG. 1(a) and then thermoset. . The size of the resin to be formed is as shown in FIG. 1(b).

That is, in FIG. 1(b), the width of the lead 2 is 0.2 mm, and the gap between the adjacent leads 2 is 0.2 mm.
The resin 4 is formed so as to straddle the outer edge of the part to be sealed with resin, and the width of this resin 4 is 0.2 m.
A length of approximately 0.5 mm is sufficient.

Next, this lead frame is clamped with a resin sealing mold, and a sealing resin is injected into the mold to perform resin sealing. The sealing resin is blocked by the formed resin 4.

In the conventional technology, as shown in FIG. 4, it was necessary to cut and remove the tie bars after resin sealing, but in this embodiment, as shown in FIG. 2, the tie bars were cut and removed after resin sealing. There is no need to do this, and the external lead can be packaged as is.

FIG. 3 is a partial plan view of a lead frame illustrating a second embodiment of the present invention. In this example, a semiconductor device is manufactured using a lead frame 10 without tie bars in accordance with the process diagram shown in FIG. 2, as in the first example. A lead frame 10 provided with protrusions 6 is used.

When such a lead frame 10 is used, the resin 4 formed in the gaps between the adjacent leads 2 is firmly fixed by the projections 6, as shown in FIG. There is an advantage that the resin 4 does not move due to the pressure of the sealing resin during sealing, and the sealing resin can be stably applied.

[0018]

[Effects of the Invention] As explained above, the present invention uses a lead frame without tie bars, and before sealing the lead frame with resin, provides resin in the gaps between a plurality of adjacent leads of the lead frame without tie bars. This has the effect of eliminating the need for an expensive press mold for cutting and removing tie bars, which conventionally had to be manufactured for each different shape of a semiconductor device. In addition, conventionally, as the pitch between leads became smaller, defects due to tie bar cutting misalignment tended to increase, but with the present invention, defects due to tie bar cutting misalignment can be completely eliminated, and a stable lead shape can be obtained. Moreover, there is an effect that the impact caused by pressing when cutting and removing the tie bars is completely eliminated, and the quality of the semiconductor device can be improved.

[Brief explanation of the drawing]

FIG. 1 is a partial plan view of a lead frame portion explaining an embodiment of the present invention.

FIG. 2 is a process diagram of the embodiment of FIG.

FIG. 3 is a partial plan view of a lead frame illustrating a second embodiment of the present invention.

FIG. 4 is a process diagram illustrating a conventional semiconductor manufacturing method.

FIG. 5 is a partial plan view of the lead frame for explaining FIG. 4;

[Explanation of symbols]

1 Element mounting part 2 Lead 3 Tie bar 4 Resin 5 Outer edge of the part to be sealed with resin 6.Protrusion 10 Lead frame

Claims (1)

[Claims] 1. A step of forming an insulating material such as resin in a portion located at the root of an external lead among the gaps between a plurality of adjacent leads of a lead frame without a tie bar;
A resin-sealed semiconductor comprising the steps of clamping the lead frame with a resin-sealing mold and sealing it with a resin, and cutting the lead frame and molding the external leads into a predetermined shape. Method of manufacturing the device.