JPH0669077B2 - Method for assembling semiconductor device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a semiconductor device assembling method, and more particularly to a lead frame end face processing technique for a resin-sealed semiconductor device.

[Background technology]

In assembling a resin-sealed semiconductor device, a long or short lead frame in which pellet supporting tabs and leads are integrated is used as a basic material for packaging.

These lead frames are formed by pressing or etching from a thin metal plate, and then formed as an integrated product with necessary plating, and various forms are supplied according to the purpose of use (Issued by the Industrial Research Board). , Electronic Materials Magazine, August 1982 issue, P69-P74).

In the present invention, there is a gassho type frame as a form of the lead frame used for the PIPOLAR DIGITAL IC. As shown in FIG. 4a, the outer leads of adjacent unit lead frames are alternately inserted to save the lead frame material by the length of one outer lead. When assembling a semiconductor device, as shown in Fig. 4b,
In the form of a short lead frame separated into 10 to 16 pieces, pelletization, wire bonding, resin sealing are performed, and solder plating is performed on a desired portion.

By the way, such a joint type short lead frame is separated by the frame (outer frame) of the lead frames at both ends as shown in FIG. 4a, so that the tips of the outer leads that enter alternately are the frame (outer frame). It becomes a shape that projects more laterally than.

Therefore, in the resin encapsulation process, the solder plating process, and the accompanying transport process, the protruding outer lead tips come into contact with the components such as the resin encapsulation device and the solder plating device delivery device, so that the outer lead does not bend. (Dotted line 5'in the figure) occurs. In such a semiconductor device having a bent lead, it is necessary to correct the bend of the lead before the inspection process for selecting a non-defective product and a defective product, which lowers the work efficiency of the inspection process.

Also, when pelletizing, wire bonding, and resin sealing are performed under the form of a long continuous lead frame and then separated into short continuous lead frames for each unit / lead frame, the same as in the case described above. In some cases, a bending defect of the outer lead occurs, which lowers the work efficiency in the inspection process and the like.

The present invention has been made to overcome such problems.

[Object of the Invention]

An object of the present invention is to protect the outer lead of the end face portion in the gassho type lead frame and improve the inspection work efficiency without lowering the efficiency of taking the frame material.

Objects and other objects and novel features of the present invention will be apparent from the description of the present specification and the accompanying drawings.

[Outline of Invention]

The outline of a typical one of the inventions disclosed in the present application will be briefly described as follows.

That is, after forming a long lead frame of the gassho type, pelletizing in the state of the long lead frame,
Wire bonding and resin sealing are performed. Next, when cutting the frame into short lead frames, the parts of the frame corresponding to the parts where the outer leads of the adjacent unit lead frames enter each other are cut diagonally and the two parts of the outer leads are separated from each other. A protective frame extending in parallel is formed, and the distal end portion of the outer lead is cut off to project the distal end of the protective frame to the outside of the distal end of the outer lead and cut into each set of unit lead frames. As a result, the protective frame protects the outer lead tips from the external force and prevents the outer lead from bending.

〔Example〕

1 and 2 are plan views showing an embodiment of the present invention.

In the method of assembling a semiconductor device, pelletization, wire bonding, and resin sealing are performed in a long lead frame state, and then the long frame is cut into short lead frames.

FIG. 1 illustrates a long reed flume. This long lead frame has two frames (outer frame) 1,
Plural sets of unit lead frames are integrally formed by the pellet mounting tab 2 integrated with the frame 1 via the tab leads 3 and the dam 6 having a large number of leads integrated therein. The lead is composed of an inner lead 4 on the side of the pellet mounting tab 2 side of the dam 6 and an outer lead 5 on the outer side. The outer leads 5 are parallel to the frame 1, and the tips of the outer leads 5 are thin as shown in FIG.

In the figure, reference numeral 7 is a sprocket hole used for positioning the dove at the time of pellet bonding, and reference numeral 8
Is a sprocket hole used for positioning the lead frame on the mold during resin molding.

The lead frame is a gas-sealed type, and as shown in FIG. 1, the outer leads 5 of one set of unit lead frames and the outer leads 5 of other adjacent unit lead frames are arranged alternately. Has been done.

The lead frame is formed into a shape as shown in FIG. 1 by pressing or etching, and then a pellet (not shown) is mounted on the pellet mounting tab 2, and a wire is connected between the electrode of the pellet and the inner lead. That is, wire bonding is performed, and the pellet is sealed with a resin mold. In FIG. 1, the broken line indicates the position where the resin mold body 9 is formed.

In this way, resin molding is performed and the resin molded body 9
The long lead frame after the formation of is formed is cut into each short unit lead frame corresponding to one unit lead frame.

At the time of this cutting, the portion of the frame 1 corresponding to the portion where the outer leads 5 of the lead frames of the adjacent units enter each other is cut diagonally with respect to the longitudinal direction (shown by a chain line in FIG. 1). And protective frame 11
To leave and cut. At the same time, the tip end portion of the outer lead 5 which is thinly shown in FIG. 1 is cut off.

As a result, the tip of the frame-separated portion a of the protective frame 11 is projected to the outside of the tip of the outer lead 5. As a result, the protection frame 11 is formed so as to extend along the outer lead 5 so as to surround it from both sides, and the outer lead 5 is protected. In this way, the protective frames 11 are formed on both sides of the outer lead 5 so as to extend outward from the outer lead 5 and protect the outer lead 5 from external force.

Preferably, the cutting angle θ is set to, for example, about 15 ° so that the sharp tip a of the protective frame 11 is projected to the outside of the outer lead 5. In this way, as shown in FIG. 2, a short lead frame in which the resin mold body 9 is integrated is formed.

By forming the protective frame 11 so that the tips of the outer leads 5 are projected to the outside of the outer leads 5 as described above, the outer leads 5 can be protected from external force and the bending thereof can be effectively prevented. it can.

Protective frame 11 protruding from the tip of the outer lead 5
It has been clarified by the present inventor that the protruding length Δl (see FIG. 6) sufficiently exhibits a role as a protective frame if Δl = 0.05 mm or more. That is,
If there is an external force applied to the outside of the outer lead 5 prior to the outer lead 5, it means that the outer lead 5 is protected. According to a study by the present inventor, the outer lead 5 is likely to be bent so that the outer lead close to the frame is generated, and the bending direction is a direction in which the tip of the outer lead 5 moves away from the frame. In other words, the bending of the outer lead 5 occurs because the outermost outer lead 5 collides first.

Therefore, the present invention contemplates attaching the protective frame 11 using the frame 1 on the outer side of the outer lead 5.

FIG. 3 is a short lead frame 1 before the appearance inspection step formed by the method of the present invention. The characteristic feature of the figure is that both ends of the short lead frame 1 are cut by the cutting method according to the present invention. Thereby, there is an effect that there is no concern that the outer leads 5 located at both ends bend together.

After that, a lead appearance inspection is performed to select defective products.
Then, separate the leads, the frame, and the leads,
The outer leads 5 are bent in the same direction to complete a resin-sealed device including individual elements.

Then, the completed semiconductor device enters a characteristic inspection process (selection) and is separated into a good product and a defective product. At this time, since the semiconductor device assembled by applying the present invention has almost no outer lead bending, the work is efficiently performed.

The present invention has been described above with reference to the drawings.

The present invention has not only the above-mentioned effects but also the following effects.

That is, during resin molding, resin injection is performed through the gate 10 opened in contact with a part of the mold frame 1 near the inner lead side. In the examples so far, as shown in FIG. 5, the distance l1 from the gate 10 to the tip is short because the frame 1 is cut at a portion close to the dam 6,
A part of the injection resin leaked from the gate 10 may come around from the outside of the frame 1 and cover the outer lead 5 with the resin, resulting in defective solder adhesion.

However, according to the present invention, as shown in FIG.
Since the outer leads are cut off at a slanting angle, the distance l2 from the gate 10 to the tip of the frame 1 can be increased, the wraparound of the resin from the gate is reduced accordingly, and the solder adhesion failure of the outer leads 5 It can be reduced.

〔The invention's effect〕

According to the present invention described in the above embodiments, the following effects can be obtained.

(1). The part of the frame that corresponds to the outer lead is cut diagonally to form a protective frame that extends parallel to each other on both sides of the outer lead, and the tip of the outer lead is cut to remove the end of the protective frame from the outer lead. The outer lead tip is physically protected from an external object and the lead bend can be prevented by projecting the tip of the outer lead to the outside and cutting each set of unit lead frames.

(2). As shown in FIG. 6, the effect of (1) above is further enhanced by making the tip of the frame longer than the tip of the outer lead by Δl = 0.05 mm or more.

(3). Due to the above (1) and (2), the appearance inspection work for the lead bending defect and the reproduction work process for the lead correction are reduced. Moreover, according to the present invention, the material collecting efficiency is secured by utilizing the gassho type lead frame.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention. Nor. For example, as shown in FIG. 7, the tip end shape of the protective frame 11 may be a shape having sides perpendicular to the longitudinal direction of the frame 1. In this case, cutting is performed as shown by the dotted line in FIG. Since the protective frame 11 having the cut shape has an increased mechanical strength, the effect of the present invention becomes remarkable.

[Field of application]

INDUSTRIAL APPLICABILITY The present invention can be applied to semiconductor devices in general that use a chisel-type lead frame.

The present invention is effective when used for assembling a bipolar IC, for example.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, and is a plan view showing a cut portion of a long continuous gassho type lead frame, and FIG. 2 shows an embodiment of the present invention, which is an enlarged plan view of a short lead frame. Fig. 3 is an overall plan view of a lead frame cut into short strips according to the present invention, Fig. 4a is an enlarged plan view showing an example of an open type lead frame, and Fig. 4b is a lead cut into short strips. FIG. 5 is an overall plan view of the frame, FIG. 5 is an enlarged plan view of a cut portion of a conventional lead frame, and FIG. 6 is a view for explaining the effect of the present invention, which is a partially enlarged plan view of the cut portion of the lead frame. FIG. 7 and FIG. 7 show an embodiment of the present invention and are plan views showing the cut shape of the frame. 1 ... Frame, 1a ... Frame separation part, 3 ... Tab lead, 4 ... Inner lead, 5 ... Outer lead, 6 ... Dam, 7,8 ... Sprocket hole, 9 ... Resin mold body, 10 …… Gate, 11 …… Protective frame.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-49-29073 (JP, A) JP-A-55-86124 (JP, A) Actually open 51-35960 (JP, U) Actual-open Sho 60- 37252 (JP, U)

Claims (1)

[Claims] 1. A plurality of sets of unit lead frames are integrally arranged on two frames extending in parallel with each other, and a tab for pellets and a dam in which a large number of leads are integrated into one set. At the same time, the outer lead located outside the dam of each of the leads is alternately inserted into the outer leads of other adjacent unit lead frames to form a long lead frame. Pellet attachment for attaching the pellet to the pellet attaching tab, wire bonding for connecting a wire between the pellet and the lead, and resin sealing for molding the pellet with resin are performed, and then outer leads of the frame Protective frame extending diagonally to both sides of the outer lead by cutting the part corresponding to Along with the formation, the tip of the outer lead is cut off so that the tip of the protective frame is protruded outside the tip of the outer lead, and is cut for each set of unit lead frames. A method for assembling a characteristic semiconductor device.