JPH05347376A - Lead frame for resin-sealed semiconductor device and manufacture of resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To reduce a cost for manufacturing, maintenance, etc., of a die required for cutting and removing a tie bar, and to improve quality of a semiconductor device by eliminating a process of cutting and removing the tie bar. CONSTITUTION:A lead frame without a tie bar having an insulating tape 5 is used in an area near an outer periphery 4 of a part to be resin-sealed. Thermosetting resin is dropped onto the insulating tape 5 in a clearance between a plurality of adjacent leads 2 and thermally set. The resin can dam sealing resin instead of a tie bar during resin sealing by a resin sealing die.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a lead frame for a resin-sealed semiconductor device and a method of manufacturing a resin-sealed semiconductor device using the lead frame.

[0002]

2. Description of the Related Art Conventionally, in a resin-sealed semiconductor device, a semiconductor element is mounted on an element mounting portion 1 of a lead frame as shown in the plan view of FIG. 4, and the element and the tip of a lead 2 are connected by a fine metal wire. After that, the lead frame is clamped with a resin-sealing die, and the sealing resin is injected into the die to resin-seal the semiconductor element mounted on the element mounting portion 1, the thin metal wires, the internal leads, and the like. Manufactured.

In this case, the resin filled in the clearance between adjacent leads in a plurality of leads led out by being sandwiched between the upper mold and the lower mold of the resin-sealed mold, surrounds the mold at a predetermined interval. Generally, the tie bars 3 are arranged so as to surround the leads and connect a plurality of leads, so that the leads are generally restrained.

After that, the tie bar is cut and removed, the outer leads are subjected to an exterior treatment such as solder plating, and the outer leads are molded into a predetermined shape to complete the semiconductor device.

[0005]

In the above-mentioned conventional technique, the tie bar connecting the plurality of leads must be cut and removed after the resin sealing. The tie bar is usually cut and removed by a mold, but it is necessary to manufacture a dedicated mold for each different shape of the semiconductor device, which is very expensive, and at the same time, it takes a long time to manufacture the mold. There is a problem.

Further, as the pitch of the external leads becomes smaller, it becomes difficult to manufacture the mold, and various problems have occurred. For example, if the external lead pitch is 0.4 mm,
When the width of the outer lead is 0.2 mm, the thickness of the tip of the cutting blade is 0.4-0.2 = 0.2 mm at maximum. In such a thin cutting blade, the blade tip is easily damaged by a load such as clogging of dust, which causes a problem that maintenance is troublesome.

Positioning of the lead frame when the tie bar is cut and removed by the die is performed by inserting a positioning pin provided in the die into a positioning hole usually provided in the lead frame. However, some misalignment occurs due to an error in manufacturing the lead frame and the mold. In the case of a semiconductor device having a small external lead pitch, there is a problem that the cutting blade bites into the lead even if the positional deviation is slight, and the cutting yield and quality are reduced.

[0008]

The lead frame for a resin-sealed semiconductor device of the present invention does not have a tie bar, but has an insulating tape along the vicinity of the outer edge of the portion to be resin-sealed. When manufacturing a resin-encapsulated semiconductor device using such a lead frame, a plurality of adjacent leads of the lead frame are provided before the step of resin-encapsulating the lead frame with a resin-sealing die. An insulating material such as resin is formed on the insulating tape in the gap.

[0009]

The present invention will be described below with reference to the drawings. 1 is a partial perspective view of a lead frame according to a first embodiment of the present invention. FIG. 2 is a partial sectional view for explaining a method of using the lead frame of FIG.

The lead frame of Example 1 is a lead frame having no tie bar, and as shown in FIG. 1, an insulating tape is formed on the back surface of the lead 2 at right angles to the lead so as to straddle the outer edge 4 of the resin-sealed portion. 5 is glued. In FIG. 1, the lead 2 has a thickness of 0.15 mm and a width of 0.2.
mm, the clearance between adjacent leads 2 is 0.2 mm, and the width of the insulating tape 5 is 1 mm. Insulation tape 5
Is made of polyimide, and an acrylic adhesive is used to bond the insulating tape 5 and the lead 2. Next, FIG.
A method of manufacturing a resin-encapsulated semiconductor device using the lead frame will be described. First, a semiconductor element is mounted on the element mounting portion (not shown) of the lead frame of FIG. 1, the element and the tip of the lead are connected by a thin metal wire, and then, as shown in FIG. A liquid thermosetting resin 6 is dropped onto the insulating tape 5 having a clearance and is thermoset. Figure 2
The cross-sectional position of corresponds to the outer edge 4 of the resin-sealed portion in FIG. In FIG. 2, the insulating tape 5 is adhered to the back surface of the lead 2, and the insulating tape 5 in the clearance of the lead 2 is attached.
The resin 6 is formed on the top.

Next, the lead frame is clamped with a resin-sealing die and the resin is sealed by injecting a sealing resin into the mold. The sealing resin is dammed by the resin 6 already formed in the gap. In the prior art, it was necessary to cut and remove the tie bar after resin sealing, but this is not necessary in this embodiment.

Next, a second embodiment will be described. FIG. 3 is a partial perspective view of the lead frame of the second embodiment. In the second embodiment, as shown in FIG. 3, the insulating tape is adhered to the vicinity of the outer edge 4 of the resin-sealed portion as in the first embodiment, but unlike the first embodiment, three types of insulating tapes are used. Are glued together. Here, the width of the first insulating tape 7 and the second insulating tape 8 is 0.5 mm, and the width of the third insulating tape 9 is 2 mm.
mm. In the second embodiment, a liquid thermosetting resin is dropped between the first insulating tape and the second insulating tape 8 so that the resin is placed on the third insulating tape 9 in the gap between the adjacent leads 2. Let it form.

In this way, the dropped liquid thermosetting resin is supported by the first insulating tape 7 and the second insulating tape 8, so that the resin can be stably formed in the clearances between the leads. The advantage is that

[0014]

As described above, according to the present invention, the insulating tape is provided in the vicinity of the outer edge of the resin-sealed portion of the lead frame having no tie bar, and the resin or the like is provided on the insulating tape having the clearances between the adjacent leads. By forming the above-mentioned insulator, it is possible to eliminate the need for an expensive press die for tie bar cutting and removing which was required to be manufactured for each different shape of the semiconductor device in the prior art.
Further, in the conventional technology, defects due to tie bar cutting misalignment tended to increase as the lead pitch decreased, but in the present invention, defects due to tie bar cutting misalignment can be completely eliminated, and a stable lead shape can be obtained. There is an effect that can be obtained. Further, in the prior art, the impact due to the press occurred when the tie bar was cut and removed, but the present invention has the effect of eliminating the impact at all and improving the quality of the semiconductor device.

[Brief description of drawings]

FIG. 1 is a partial perspective view of a lead frame according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view illustrating a method of using the lead frame of FIG.

FIG. 3 is a partial perspective view of a lead frame according to a second embodiment of the present invention.

FIG. 4 is a partial plan view of a conventional lead frame.

[Explanation of symbols]

 1 Element mounting part 2 Lead 3 Tie bar 4 Outer edge of resin-sealed part 5 Insulating tape 6 Resin 7 First insulating tape 8 Second insulating tape 9 Third insulating tape

Claims (3)

[Claims] 1. A resin-encapsulated semiconductor device lead frame, wherein an insulating tape is attached along the vicinity of an outer edge of a resin-sealed portion of a lead frame in which a tie bar is not formed. Lead frame for encapsulated semiconductor device. 2. A method for manufacturing a resin-encapsulated semiconductor device, wherein the lead frame is used, and before the die is clamped by a resin-encapsulated mold, the gap among a plurality of leads adjacent to each other in the lead frame is used. A method of manufacturing a resin-encapsulated semiconductor device, comprising a step of forming an insulator on an insulating tape. 3. A method of manufacturing a resin-sealed semiconductor device, wherein a lead frame formed by the manufacturing method is used, and an outer edge portion of a cavity of the resin-sealed mold is mounted on the lead frame. A method of manufacturing a resin-encapsulated semiconductor device, comprising the steps of: locating at, and clamping with a resin.