JPH10189859A - Lead frame for semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a lead frame for semiconductor device with stable bend shape precision, capable of relieving the impact force during in a tie bar cutting time. SOLUTION: This lead frame for semiconductor device is provided with a tie pad 1, outer leads 2 connecting to a semiconductor element by bonding wire, a tie bar 3 intermediately supporting the outer leads 2, slits 6 formed on the tie bar 3 and a frame 4 supporting the outer leas 2 on the ends. The slits 6 are formed within the width of the outer leads 2. On the other hand, for the shape of the slits 6 includes a polygon, an elipse and a circle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame of a thick type semiconductor device used for a power PKG or the like.

[0002]

2. Description of the Related Art Conventionally, a power PKG or the like has a resistance of 0.3 to
A thick type lead frame having a thickness of 0.4 mm is used. FIG. 3 shows a plan view of a lead frame of a conventional thick type semiconductor device having a thickness of 0.3 mm. FIG.
In the figure, 11 is a die pad on which a semiconductor element (not shown) is mounted, 12 is an external lead lead having one end wire-bonded to the semiconductor element, and 13 is an external lead 12
Is a frame supporting the die pad 11 and the external lead 12 at the other end, and 15 is a molding line of the sealing resin. The tie bar 13 is necessary to prevent deformation of the external lead-out lead 12 and also to suppress the progress of resin burrs generated during resin formation.

The tie bar 13 becomes unnecessary after the resin is formed, and is cut together with the frame 14 before bending. E in FIG. 3 indicates a cut line of the tie bar 13, and an enlarged view of an IV portion is shown in FIG.

[0004]

In the conventional lead frame of a semiconductor device, when the tie bar 13 is cut after the resin is formed, the thickness of the lead frame is large. There is a problem that peeling from the sealing resin occurs.

[0005] As shown in FIG. 4, after cutting the tie bar 13, convex uncut portions 16 are formed on both sides of the external lead-out lead 12. When the uncut portion 16 is hung on the bend portion, the bend processing becomes difficult, and there is a problem that the accuracy of the bend shape is not obtained. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems, and an object of the present invention is to provide a lead frame of a semiconductor device which can reduce an impact force at the time of tie bar cutting and has a stable bend shape accuracy.

[0006]

A lead frame of a semiconductor device according to the present invention comprises a die pad, an external lead connected to a semiconductor element on the die pad by a bonding wire, a tie bar supporting the external lead in the middle, and a tie bar. And a frame that supports the external lead-out lead at the end.

The shape of the slit may be polygonal, elliptical, circular or the like. According to the lead frame of the semiconductor device of the present invention, by forming the slit in the tie bar, the effective size of the tie bar is reduced, the impact force at the time of cutting the tie bar can be reduced, and the semiconductor device can be cut at the time of cutting with the cutting blade. The distortion generated at the interface between the lead frame and the sealing resin can be absorbed. Further, by forming the slit, the lead width after the tie bar cut is reduced, and the lead can be bent with high accuracy at the center of the cut portion, and the bend accuracy is stabilized and bend processing can be easily performed.

The slit may be formed so as to reach the width of the external lead. As a result, the lead width after the tie bar cut is further reduced, and bend processing is facilitated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG.
1 shows a plan view of a lead frame of a semiconductor device according to one embodiment. In FIG. 1, reference numeral 1 denotes a die pad on which a semiconductor element (not shown) is mounted, 2 denotes an external lead having one end wire-bonded to the semiconductor element, 3 denotes a tie bar for supporting the external lead 2 in the middle, 4 denotes a die pad 1 And a frame for supporting the external lead 2 at the other end. Reference numeral 5 denotes a molding line of the sealing resin.

Reference numeral 6 denotes a slit formed in the tie bar 3. The slit 6 is formed in a rectangular shape reaching the width of the external lead 2. That is, as shown in FIG. 2 which is an enlarged view of a portion II in FIG. 1, the amount of penetration 2C of the slit 6 into the width of the external lead 2 is considered from the lead bending strength, and the width B of the external lead 2 is considered. Is preferably less than 10%. For example, the width dimension B of the external lead 2 is 0.2
In the case of 8 mm, the biting amount C of the slit 6 is set to 0.014 mm or less.

Next, the assembly of the lead frame of the semiconductor device will be described. First, a lead frame of a semiconductor device is formed of resin. Then, the tie bar 3 having the rectangular slit 6 and the frame 4 are cut. Further, in FIG.
Indicates a cut line of the tie bar 3. Bend processing is performed on the tie bar cut external lead 2. According to the lead frame of the semiconductor device configured as described above, the slit 6 is formed in the tie bar 3, so that the effective size of the tie bar 3 is reduced and the contact area of the cutting blade is also reduced, so that the tie bar 3 is added to the lead frame. The impact force is reduced, and the distortion generated at the interface between the lead frame and the sealing resin when cutting with the cutting blade can be absorbed.

As shown in FIG. 2, both sides of the external lead 2 after the tie bar cut are concave, and the lead width D
As a result, the lead can be bent accurately at the center of the cut portion, the bend accuracy is stabilized, and bend processing can be easily performed. In the above-described embodiment, the slit 6 has a rectangular shape, but the slit shape may be a polygon other than a square, an ellipse, a circle, or the like. Further, the slit does not need to reach the width of the external lead 2. For example, a circular slit may be formed in the tie bar 3 without reaching the width of the external lead 2. As described above, even if the slit does not reach the width of the external lead 2, the impact force at the time of cutting and the width of the lead after cutting can be reduced as compared with a conventional tie bar having no slit.

[0013]

According to the lead frame of the semiconductor device of the present invention, the slit is formed in the tie bar.
The effective size of the tie bar is reduced, the impact force at the time of cutting the tie bar can be reduced, and the strain generated at the interface between the lead frame of the semiconductor device and the sealing resin when cutting with the cutting blade can be absorbed. The life of the blade can be extended. Further, by forming the slit, the lead width after the tie bar cut is reduced, and the lead can be bent with high accuracy at the center of the cut portion, and the bend accuracy is stabilized and bend processing can be easily performed.

The slit may be formed so as to reach the width of the external lead. As a result, the lead width after the tie bar cut is further reduced, and bend processing is facilitated.

[Brief description of the drawings]

FIG. 1 is a plan view of a lead frame of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a portion II in FIG.

FIG. 3 is a plan view of a lead frame of a conventional semiconductor device.

FIG. 4 is an enlarged view of a portion IV in FIG. 3;

[Explanation of symbols]

 1 die pad 2 external lead 3 tie bar 4 frame 6 slit

Claims (5)

[Claims] 1. A die pad, an external lead connected to a semiconductor element on the die pad by a bonding wire, a tie bar supporting the external lead in the middle, a slit formed in the tie bar, and the external lead. A lead frame for a semiconductor device having a frame supported at an end. 2. The lead frame of a semiconductor device according to claim 1, wherein the slit extends within a width of the external lead. 3. The lead frame of a semiconductor device according to claim 1, wherein the slit has a polygonal shape. 4. The lead frame of a semiconductor device according to claim 1, wherein the shape of the slit is elliptical. 5. The lead frame of a semiconductor device according to claim 1, wherein the slit has a circular shape.