JPH0637232A - Method of manufacturing lead frame and semiconductor device using the same - Google Patents

Abstract

PURPOSE:To manufacture the title semiconductor device having enhanced dimemsional precision and high reliability by a method wherein a semiconductor chip is mounted on a lead frame and after electrical connectin and formation- sealing a resin package, a side bar and a lead frame are cut off leaving a supporting lead only. CONSTITUTION:A supporting lead 8 electrically disconnected from a semiconductor chip 5 is to be left intact in the state fixed to a side bar 7 even after the connecting parts between the outer leads 3 led out of a resin package 4 and the side bar 7 are cut off. Thus, the deformation of the outer leads 3 can be notably reduced. Besides, the packaging density on a packaging substrate can be increased. Furthermore, the excellent positional precision of the outer leads 3 can be maintained so that the title highly reliable semiconductor device in high dimensional precision making no defective shortcircuit between the outer leads 3 can be manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame and a method for manufacturing a semiconductor device using the same, and more particularly to a structure for preventing deformation of outer leads.

[0002]

2. Description of the Related Art Lead frames for semiconductor devices such as ICs and LSIs are formed into a predetermined shape after removing unnecessary portions of a metal strip by a photoetching method or a pressing method. It is formed through a plating process of plating parts and a taping process of attaching a tape and fixing the inner leads to each other. Here, of the leads, the inner side and the outer side of the package line are referred to as inner leads and outer leads, respectively.

By the way, in recent years, surface mounting technology for connecting the tips of the outer leads to a wiring pattern formed on the surface of the mounting substrate has become popular. In the case of the surface mounting technology, the outer leads are formed in a J-shape. Bending to form the outer lead surface (semiconductor element mounting surface side) on the wiring pattern, and bending the outer lead into an L shape to form the back surface of the outer lead (back side of the semiconductor element mounting surface) on the wiring pattern. The method of doing so has been put into practical use, and all of these require bending the outer lead. For this reason,
The outer lead is becoming finer and the plate thickness is becoming thinner.In particular, when bending the outer lead in this way, the stress applied during bending causes the outer lead to be distorted, and this stress causes In some cases, this could cause a short circuit between the leads. Further, as shown in FIGS. 8 and 9, when the semiconductor device formed in this manner is transferred onto the mounting substrate,
There is a problem that the outer lead is deformed. The positional deviation due to the distortion of the outer leads causes a connection failure with the wiring pattern of the mounting board.

Further, not only in the case of surface mounting, but also the problem of the deformation of the outer leads often causes a decrease in reliability.

Therefore, as shown in FIG. 10, after the resin sealing and the side bar are cut off, the outer lead 3 is removed.
MC which reinforced the tip part of the frame with resin frame M and conveys it
Although what is called R (: mold carrier ring lead frame) has also been proposed, there is a problem that the end user must cut out the frame and mold the outer lead when mounting on a circuit board.

[0006]

As described above, in the conventional semiconductor device, the reliability is lowered due to the deformation of the outer lead or the detachment from the resin package due to the stress applied during bending of the outer lead or the stress applied during transportation. There were various problems that caused

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a semiconductor device having good dimensional accuracy and high reliability.

[0008]

In view of the above, the present invention is provided with a supporting lead supported by the side bar.

Further, according to the method of the present invention, a lead frame having a plurality of leads extending outward from around the semiconductor element mounting portion and a side bar for supporting the leads is formed, and the lead frame is formed on the semiconductor element mounting portion. At least one of the above leads is used as a supporting lead by fixing a semiconductor element to the
Electrical connection with the semiconductor element is made except for the lead, and a resin package is formed and sealed so as to cover the lead frame and the semiconductor element while leaving the vicinity of the outer end of the lead. The lead frame other than the supporting lead of the lead frame and the side bar are cut and molded, and the supporting lead is cut off immediately before mounting. Desirably, the supporting leads form a support bar.

[0010]

According to the above construction, even after the outer lead molding,
Since the lead frame can be supported by the side bar via the supporting leads, even when the material is made thin, it is supported by the side bar until just before mounting, and therefore the strength can be sufficiently maintained. it can. In addition, the user can mount the support lead on the circuit board only by disconnecting the supporting lead from the side bar, and thus the workability is good.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings.

A semiconductor device according to an embodiment of the present invention is shown in FIG. 1 (a) in a perspective view, and FIGS. 1 (b) and 1 (c) in a resin package as shown in FIG. 1 (a). Even after the outer lead 3 derived from No. 4 cuts off the connection portion with the side bar 7, the support lead 8 not electrically connected to the semiconductor chip is fixed to the side bar and remains. It is characterized by that.

2 (a) to 2 (d) are views showing a manufacturing process of a semiconductor device according to an embodiment of the present invention.

First, as shown in FIG. 2A, a band-shaped material called an alloy 42 is formed side by side with the inner lead 1, the outer lead 3 and the outer lead using a progressive die to form a support lead. 2 is a dam bar and 7 is a side bar.

In this way, after the lead frame is shaped, the coining step, the noble metal plating step, the taping step, the annealing step, etc. are performed to complete the formation of the lead frame.

Then, as shown in FIG. 2 (b), the thin portion of the inner lead tip of the lead frame is positioned so as to abut on the bonding pad of the semiconductor chip, and then the bonding head (not shown) from the thin portion side. ), The tip thin portion of the lead frame and each bonding pad of the semiconductor chip 5 are directly joined by bumps.

After that, as shown in FIG. 2 (c), the mold is set in a mold, filled with a sealing resin, and molded.

Finally, as shown in FIG. 2D, the outer lead 3 is cut off from the dam bar 2 and the side bar 7, and the semiconductor device as shown in FIG. 1 is completed.

As shown in FIG. 3, the semiconductor device is placed in a carrier case having a recess for supporting side rails and conveyed to the vicinity of a printed circuit board for mounting, where the side bar and supporting leads are cut off. And is mounted on the wiring pattern on the printed circuit board.

In the semiconductor device thus obtained, the deformation of the outer leads can be significantly reduced as compared with the conventional surface mounting type semiconductor device, and the mounting density on the mounting substrate can be increased. .

Furthermore, it is possible to maintain a good positional accuracy of the outer leads, and it is possible to obtain a highly reliable semiconductor device having a high dimensional accuracy and no short circuit defects between the outer leads. In addition, although the lead frame having the supporting leads has been described in the above embodiment, FIG.
Further, as shown in a modified example in FIG. 5, the support bar 9 may be left as a supporting bar to the end and removed immediately before mounting on the mounting board. Here, FIG. 4 shows a lead frame, and FIG. 5 is a view showing a semiconductor device after resin molding and outer lead molding using this lead frame.

Further, although the lead frame for direct bonding is described in the above-mentioned embodiment, it is needless to say that it is applicable to the lead frame for wire bonding, and also applicable to the film carrier and the like. .

Further, as shown in FIG. 6 as another embodiment of the present invention, the distance L between adjacent lead frame units is made approximately the same as the width W of the side bar 7, so that each semiconductor after mounting is mounted. The device can be reinforced not only by the side bar 7 but also by a reinforced part which is sufficiently wide from four sides as shown in FIG. 7, and the reliability is further improved.

[0024]

As described above, according to the present invention, since the lead frame can be supported by the side bar until just before mounting on the mounting board, there is no distortion or displacement of the outer leads, and the reliability is extremely high. It is possible to obtain a semiconductor device having a high price.

[Brief description of drawings]

FIG. 1 is a diagram showing a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of a semiconductor device according to an embodiment of the present invention.

FIG. 3 is a diagram showing a mounted state of a semiconductor device according to an embodiment of the present invention.

FIG. 4 is a diagram showing a lead frame according to another embodiment of the present invention.

FIG. 5 is a diagram showing a semiconductor device according to another embodiment of the present invention.

FIG. 6 is a diagram showing a lead frame according to another embodiment of the present invention.

FIG. 7 is a diagram showing a semiconductor device according to another embodiment of the present invention.

FIG. 8 is a diagram showing a conventional semiconductor device.

FIG. 9 is a diagram showing a conventional semiconductor device.

FIG. 10 is a diagram showing a conventional semiconductor device.

[Explanation of symbols]

 1 Inner Lead 2 Dam Bar 3 Outer Lead 4 Package 5 Semiconductor Chip 7 Side Bar 8 Supporting Lead 9 Support Bar M Resin Frame

Claims (3)

[Claims] 1. A plurality of leads extending outward from around a semiconductor element mounting portion, a side bar for supporting the leads, and a support lead supported by the side bar. Lead frame. 2. A lead frame forming step of forming a lead frame including a plurality of leads extending outward from around a semiconductor element mounting portion, and a side bar supporting the leads, and the semiconductor element mounting portion. A semiconductor element is fixed on top of the lead, and a fixing step of electrically connecting to the semiconductor element except at least one lead serving as a supporting lead among the leads and a portion near the outer end of the lead are left. A resin package to form a resin package so as to cover the lead frame and the semiconductor element, and to seal the lead frame and the side bar, except for the supporting leads of the lead frame. A method of manufacturing a semiconductor device, comprising: a molding step. 3. The support lead is a support bar for supporting a semiconductor element mounting portion.
A method for manufacturing a semiconductor device as described above.