JPH05326782A - Lead frame and semiconductor device provided therewith - Google Patents

Abstract

PURPOSE:To obtain a lead frame which restrains the mismounting of a semiconductor element caused by the bend of leads at positioning and a semiconductor device equipped with the lead frame by a method wherein a lead forming part is lessened in sectional area and curvature so as to enable leads to be easily formed under small stress in a semiconductor forming process. CONSTITUTION:A lead frame 1 is used in a surface-mounting resin diode, a groove 2 is provided to the lead frame 1 to lessen it in sectional area, and a front groove 2a and a rear groove 2b are formed by punching on both the ends of the groove 2 where leads are bent in an after forming process corresponding to the sealing part 3 of the lead frame 1 when the lead frame 1 is formed through a punching operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame for a semiconductor device, and more particularly to a lead frame in which leads can be easily formed in a forming process of a semiconductor device and a semiconductor device using the lead frame. And about effective technology.

[0002]

2. Description of the Related Art Conventionally, as a semiconductor device requiring lead molding, for example, in a surface mount type resin diode, the lead cross-sectional shape is the same between the lead-molded portion and the non-molded portion, and in particular, a groove is provided in advance. Is not processed.

An example of this type of assembly technique is the technique described in "LSI Handbook" P406 to P416, published by the Institute of Electronics and Communication Engineers, November 30, 1984.

[0004]

However, in the prior art as described above, no consideration is given to facilitating the molding of the leads of the semiconductor device, and the curvature of the lead molding portion becomes large, so that the semiconductor device becomes large. There is a problem that a handling mistake is likely to occur when implementing.

That is, when the curvature of the lead forming portion is large, the gap between the package and the lead becomes large, and the lead is bent when the mounting machine is positioned, so that there is a problem that it cannot be positioned and conveyed to a proper position.

In addition, there is a problem that bending stress is applied to the root of the lead with respect to the package at the time of lead molding, the package is sometimes chipped, or the adhesion between the package and the lead is deteriorated, resulting in poor moisture resistance of the semiconductor device.

In view of this, the inventor of the present invention pays attention to the fact that in the lead forming of a semiconductor device, the lead becomes easier to bend when the lead has a smaller cross-sectional area. It has been found that the lead can be easily bent by applying a process of making it smaller.

That is, an object of the present invention is to provide a lead frame and a semiconductor device using the same which can reduce the cross-sectional area of the lead forming part and easily perform the lead forming with a low stress in the forming process of the semiconductor device. To provide.

Another object of the present invention is to provide a lead frame and a semiconductor device using the same which can reduce the curvature of the lead molding portion and suppress mounting mistakes due to bending of the leads during positioning. is there.

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

[0011]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, in the lead frame of the present invention, before the forming step of the semiconductor device, in order to facilitate lead forming in the forming step, the lead frame is bent at a portion known to be bent in advance in the lead frame. The processing is performed in advance so that the cross-sectional area is smaller than the non-existing portion.

Further, the semiconductor device of the present invention is characterized in that when the leads of the semiconductor device are molded using the lead frame,
Lead molding is performed by using a portion processed to have a small cross-sectional area.

[0014]

According to the lead frame and the semiconductor device using the lead frame described above, the portion which is known to bend the lead is preliminarily processed to reduce the sectional area, so that the sectional area of the portion where the lead is molded is reduced. It can be made smaller than the cross-sectional area of the unmolded portion, and the lead can be molded with low stress by performing the lead molding using the portion processed to have a small cross-sectional area.

Further, since the curvature of the portion where the leads are formed can be reduced and the gap between the package and the leads can be narrowed, it is possible to suppress the bending of the leads during positioning by the mounting machine.

[0016]

1 (a) and 1 (b) are a plan view and a side view showing a lead frame according to an embodiment of the present invention, and FIG. 2 is a side view showing a semiconductor device using the lead frame of the present embodiment. Is.

First, the structure of the lead frame of this embodiment will be described with reference to FIG.

The lead frame of this embodiment is a lead frame used in, for example, a surface mount resin diode, and the lead frame 1 is provided with a groove 2 as a process for reducing the cross-sectional area of the lead. When the lead frame 1 is punched and manufactured, for example, the front side groove 2a and the back side groove 2b are punched at the portions where the leads are bent in the subsequent forming step, that is, at both ends corresponding to the sealing portion 3 of the lead frame 1. Is formed by.

Next, the operation of this embodiment will be described.

The lead frame 1 formed as described above
Is a surface-mounting type resin that is composed of a package 4 and leads 5 that are externally sealed with a resin as shown in FIG. 2 after undergoing various steps such as assembly, sealing, soldering, and marking, and after a forming step. It becomes a diode.

In the forming step in this case, first, the groove 2a on the front side of the lead 5 is utilized to reduce the gap with the package 4 due to the small curvature and to suppress the bending stress applied to the root portion of the package 4. , The lead 5 can be formed along the side surface of the package 4 and the groove 2a on the front side inside with low stress.

Further, by utilizing the back side groove 2b, the back side groove 2 has a small curvature like the front side groove 2a and a low stress.
The surface mounting portion can be formed by molding the lead 5 inward of b, that is, in the direction opposite to the formation of the groove 2a on the front side.

When the resin diode thus formed is mounted on, for example, a printed circuit board (not shown), since the gap between the package 4 and the lead 5 is small, the lead 5 does not bend when the mounting machine is positioned. ,
It can be positioned and transported to a regular position for mounting.

Therefore, according to the lead frame 1 of the present embodiment, since the groove 2 is formed in the bent portion of the lead 5, the curvature of the molded portion of the lead 5 can be reduced in the forming step. It is possible to narrow the gap between the package 4 and the lead 5 so as to facilitate positioning during mounting.

Further, since the cross-sectional area of the portion where the lead 5 is formed can be made smaller than the cross-sectional area of the portion where the lead 5 is not formed, bending stress is not applied to the root portion of the package 4 and the lead 5, and the lead 5 can be applied with low stress. Can be molded.

The invention made by the present inventor has been specifically described above based on the embodiments, but the present invention is not limited to the embodiments and can be variously modified without departing from the scope of the invention. Needless to say.

For example, with respect to the lead frame 1 of this embodiment, the case where the groove 2 is formed by punching at the time of punching production has been described, but the present invention is not limited to the above embodiment, and perforations such as perforation processing are performed. Any method that can reduce the cross-sectional area of the bent portion can be similarly applied, and the processing method in this case can also be formed by cutting or etching.

Further, the steps of reducing the cross-sectional area of the lead bent portion can be performed in any order before the forming step.

In the above description, the invention mainly made by the present inventor is applied to the lead frame 1 used for the surface mount type resin diode which is the field of use thereof, but the invention is not limited to this. ,
The present invention is widely applicable to other semiconductor devices such as transistors, and semiconductor integrated circuit devices that require lead forming in the forming process.

[0030]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

(1). Prior to the forming process of the semiconductor device, the lead frame is preliminarily processed to have a smaller cross-sectional area than the unbent portion of the lead frame. Since the cross-sectional area of the portion to be molded can be made smaller than the cross-sectional area of the portion not to be molded, lead molding can be easily performed with low stress by using the portion processed to have a small cross-sectional area.

(2) According to the above (1), the curvature of the portion where the leads are formed in the forming process can be reduced and the gap between the package and the leads can be narrowed, so that the lead bending at the time of positioning by the mounting machine can be prevented. Therefore, it is possible to suppress mounting mistakes.

(3) Due to the above (1), bending stress is not applied to the root portion of the package during lead molding, so that the chipping of the package or the adhesion between the package and the lead is improved, and the moisture resistance of the semiconductor device is improved. It is possible to improve the sex.

(4). Lead molding according to the above (1) to (3),
Since it is possible to reduce mounting and poor moisture resistance, it is possible to obtain a lead frame and a semiconductor device using the same, which can improve product yield and throughput.

[Brief description of drawings]

1A and 1B are a plan view and a side view showing a lead frame which is an embodiment of the present invention.

FIG. 2 is a side view showing a semiconductor device using the lead frame of the present embodiment.

[Explanation of symbols]

 1 Lead Frame 2 Groove 2a Front Side Groove 2b Back Side Groove 3 Sealing Part 4 Package 5 Lead

Claims (2)

[Claims] 1. Before the forming step of a semiconductor device,
In order to facilitate lead forming in the forming step, a lead frame is preliminarily processed to reduce a cross-sectional area of a portion of the lead frame where it is known that the lead will be bent in advance. 2. A semiconductor device using the lead frame according to claim 1, wherein when forming the leads of the semiconductor device, the lead is formed by utilizing a portion processed to have a small sectional area. ..