JPH04196257A - Lead formation method of semiconductor device - Google Patents

Abstract

PURPOSE:To avoid the development of such defects as the surface flaws of an outer leads and the plating release by a method wherein the outer leads are bend-formed by pressing down a bonding punch in almost rectangular direction. CONSTITUTION:The title lead is stamped in the shape of lead frame connected to a semiconductor device further connecting to the end of an outer leads 2 and then the flat braiding step to avoid the deformation in the second step further facilitating the performance in the third step is corrected while the outer leads 2 given an oblique shape in the third step are pressed down by a bending punch 15 in almost rectangular direction to bend-form the outer leads 2 in the gull wing shape at one stroke. Furthermore, in the fourth step, the connection part 3 at the end of the outer lead 2 is cut off so as to correct the deformation and the scratches in the halfway steps for making the whole steps acceptable. Through these procedures, the end of the outer leads can be excellently bend-formed to make the lead products without developing such defects as the plating release, the deformation and so forth.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for bending outer leads that protrude outside after a lead frame is resin-sealed in a package.

[Conventional technology]

For example, in the process of bending a semiconductor device with glue,
The methods described in Japanese Patent Publication No. 1-119251 and Japanese Patent Publication No. 1-26177 are employed. All of these utilize rollers to bend the outer lead.

Furthermore, as shown in FIG. 5, bending using a bending punch has also been conventionally performed.

To explain the molding process in this device, the semiconductor device 30 separated from the lead frame is shown in FIG.
It is set in a bending die 31 as shown in FIG. Then, the stripper 32 is lowered and the base of the lead 35 is clamped by the support part 33 of the bending die 31 and the suppression part 34 of the stripper 32, and then the bending punch 36 is lowered.
(See the same figure (bl). At this time, the slope of the bending punch 36 cooperates with the slope 37 of the support part 33 to form an inclined bent part on the lead, and the flat pressing part of the bending punch 36 cooperates with the slope of the bending die. A tip part is formed on the lead 39 in cooperation with the flat part 38 of [3], and a gull wing tie lead is formed in one step.After forming the lead 39, the same IU (as shown in CI), the bending punch 36 and raise the stripper 32,
The molding process is completed by taking out the semiconductor device 30, on which the leads 35 have been molded, from the bending die 31.

[Invention or problem to be solved]

However, in the case of roller bending, the tip of the outer lead is forced forward due to rolling of the peripheral surface of the roller, which tends to cause scratches on the surface of the outer lead.

Furthermore, even in the case where the bending punch shown in Fig. 5 is used, a sliding surface occurs between the surface of the outer lead and the surface of the outer lead in the direction of movement of the punch. The occurrence of plating defects and plating whiskers is unavoidable.

As described above, conventional bending methods often have a negative effect on the tip of the outer lead, and this tendency is particularly noticeable in the case of multiple pins because the width of the tip of the lead is small.

The problem to be solved in the present invention is to obtain a lead product by bending the tip of the outer lead in a good manner so as to prevent peeling of plating or other deformation.

[Means to solve the problem]

The present invention provides a method for bending and forming an outer lead of a semiconductor device into a gull wing type, in which the first step is a method for bending and forming an outer 1 note of a resin-packaged semiconductor device into a gull wing type.
In the process, a punching process is performed to separate the resin-packaged semiconductor devices in a shape that connects the terminal portions at the tips of the outer leads of the lead frames connected together, leaving a connecting portion.The second step is to separate the semiconductor devices separated from the lead frames. A straightening process is performed by flattening the outer lead in an inclined shape using a straightening punch and a die, and in a third step, a gull wing-shaped bent portion is formed on the outer lead after the above straightening using a bending punch that can be freely moved from a substantially perpendicular direction. The method is characterized in that bending is performed, and in a fourth step, the tip of the outer lead is punched out to remove the connecting portion.

[Effect]

In the present invention, in the first step, a lead frame in which semiconductor devices are connected is punched in a shape in which the tips of the outer leads are connected, and in the second step, the lead frame is punched to prevent deformation (and the third
To make the process easier, the flattening process is corrected, and in the third step, the slanted outer lead is pressed with a bending punch from an almost right angle direction to bend and form the gull-wing shaped outer lead in one stroke. Further, in the fourth step, the connecting portion at the tip of the outer lead is cut, thereby eliminating deformation or damage to the product during the process, and achieving good processing.

〔Example〕

Fig. 1 is a diagram showing the bending process of the present invention, Fig. 2 is a plan view of the lead frame, Fig. 3 is a perspective view of the obtained semiconductor device, and Fig. 4 is a schematic diagram of the bending device. be.

FIG. 1 (Al is a plan view of a single lead frame. Outer leads 2 protrude from the resin PC cane l in all directions. The tip portions of the outer leads 2 are connected by a connecting part 3. A single lead frame like this is obtained by punching out a lead frame 4 shown in Fig. 2.A resin package 1 is continuously arranged on the lead frame 4, and from this resin package I, there are four parts. The outer lead 2 is extruded and molded. A connecting portion forming perforated portion 5 is formed at the front of the outer lead 2, and a connecting portion 3 is formed in the middle thereof. Reference numeral 6 in the figure is a sight rail.

As shown in FIG. 1 (bl), the single piece punched into the shape shown in FIG. 1 (al) is bent upward to the outer lead 2 to remove distortion. The resin package 1 is placed on top, and the stripper 8 and the first
The outer lead 2 is clamped between the straightening diamond, and then the first straightening punch 9 is lowered to bend the outer lead 2 to correct the distortion. In the same figure (C), the outer lead 2 which has been bent upward is placed on a bending die 10, is clamped with a stripper 11, and is then bent with a second straightening punch 12.
is lowered and flattened to remove distortion. By correcting the vertical bending in this way, the inclinations of the many leads become uniform.

The steps shown in FIGS. 1(d) and 1(e) are the main parts of the processing method of the present invention, and the characteristics thereof are that the step is supported by the slide plate 13, is pressed down by the cam drive unit 14, and moves in the direction of the outer lead 2. The bending punch 15 and its diagonal movement.

In the figure, the bending die 16 is formed into a gull wing shape having a flat part 17 and an inclined part 18. A bending punch 15 is provided which is movable from a substantially perpendicular direction to the outer lead 2 which is placed in a downwardly inclined manner. The bending punch 15 has a gull wing-shaped tip and can move forward and backward along the slide plate 13. That is, the cam drive section 14 is lowered and then engages with the bending punch 15 to push the punch 15 down. Further, the bunch 15 can be moved upward by the compression coil spring 19. 20
indicates a stripper.

FIG. 5(e) shows a state in which the cam drive unit 14 is lowered, the punch 15 is moved downward, and the outer lead 2 is bent into a gull wing shape with one stroke. In this bending process, the bending punch 15 presses the outer lead 2 from a direction substantially perpendicular to the outer lead 2, so that no force is applied to the outer lead 2.

Note that the moving direction of the bending punch 15 is θ in the figure.
゛ It is designed so that ζθ/2.

The bending punch 15 can be moved forward and backward by a device shown in FIG. That is, the stripper 20 is lowered by a drive device (not shown) to bend the bending die 1.
The outer lead 2 is clamped between the clamp part 21 of No. 6, and then the cam drive part 14 or the bending punch 15 is pushed. At this time, the bending punch 15 compresses the compression coil spring 19 while sliding along the slide plate 13. When the bending of the outer lead 2 is completed and the cam drive unit 14 is raised, the bending punch 15 is moved upward by the restoring force of the compression coil spring 19.

Figure 1) shows the process of punching out the connecting portion 3 at the tip of the outer lead 2 using the connecting portion removal punch 22. In the figure, 23 is a connecting portion removing die.

In addition, the connecting part 3 can be connected using the structure shown in the same figure (g).
When cutting the outer lead 2, the tip of the outer lead 2 comes out at the top or the top, making it easier for solder to stick when mounting it on a printed circuit board. 24 indicates a die.

Through the steps described above, a semiconductor device as shown in FIG. 3 is obtained.

Since the trowel bending punch 15 has the above-mentioned shape and direction of advance toward the outer lead 2, it can be embossed with one stroke. Therefore, the bending process can be performed without slipping on the outer lead 2, and the process can be performed without peeling of plating or the like.

〔Effect of the invention〕

According to the present invention, surface flaws on the outer lead and peeling of the plating do not occur even though the bending process is performed by pressing the bending punch or the outer lead from a substantially perpendicular direction to embossing the outer lead.

Furthermore, since the connecting portion remains until the final process, the outer lead is less likely to be deformed or damaged, improving the quality of the product.

[Brief explanation of the drawing]

FIG. 1 is a process diagram of bending work showing one embodiment of the present invention. A process diagram of bending and straightening, Figure (d) is a diagram of the state before bending and forming into a gullwing shape, Figure (e) is a diagram of the state after bending and punching the outer lead and forming it by bending.
g) is a state diagram of the removal punching process of the connection part, FIG. 2 is a plan view of the lead frame, FIG. 3 is a perspective view of the obtained semiconductor device, FIG. 4 is a schematic diagram of the bending device, and FIG. 5 1 is a process diagram of a conventional method for molding a sheet. l Resin package 2 Outer lead 3 Connecting part 4・Lead frame 5 Connecting part molding perforation part 6・Side rail A First correction die
8 Stripper 9 First correction punch 10 Bending die 11 Stripper 12 Second
Correction punch 13 Slide plate I4 Cam drive unit 15 Bending punch 16 Bending die 17 - flat part 18 Inclined part 19
Compression coil spring 20, stripper 21, clamp part 22 connection part removal punch 23, connection part removal die 24 Die patent applicant Co., Ltd.
Mitsui High Chick Agent Masu Kobori Figure 5 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. In the method of bending and forming the outer leads of a semiconductor device into a gull-wing type, the first step is to separate the resin-packaged semiconductor devices into a connected lead frame, leaving a connecting portion connecting the terminal portions at the tips of the outer leads. In the second step, the outer leads of the semiconductor device separated from the lead frame are flattened in an inclined shape using a straightening punch and die, and in the third step, the outer leads that have been subjected to the above straightening are A bending process is performed to form a gull wing-shaped bent part using a movable bending punch from a direction substantially perpendicular to the outer lead, and in a fourth step, the tip of the outer lead is punched out to remove the connecting part. Equipment lead forming method.