JPH0368536B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for forming external leads of a semiconductor device, which involves bending external leads of a semiconductor device into a predetermined shape.

(Prior art and its problems) There are various methods for bending the external leads of semiconductor devices, but micro-racks may occur between the external leads and the resin part, and the surface treatment of the external leads (e.g. The frictional force between the solder plating and the punch caused the surface treatment material to peel off or cause thickness unevenness, deteriorating the quality of the product.

Therefore, this invention prevents the surface treatment material from peeling off,
It is an object of the present invention to provide a method for forming an external lead that does not cause microcracks.

(Means for Solving the Problems) The present invention eliminates the above problems and includes the following configuration.

In J-bending of an external lead of a molded semiconductor device, the middle part of the external lead is clamped from both sides to make the tip free, and the free end side is pressed to form a substantially right angle near the clamped part. a first bending step in which the base of the external lead is clamped to free the intermediate part and tip direction of the external lead, and the vicinity of the intermediate part is pressed in the same direction as the bending process in the first bending process in the vicinity of the base. A second bending step of preliminary bending at an angle of 90° or less, and following the second bending step, the bending position in the second bending step is further bent by applying a bending punch to the external lead without slipping. It is characterized by comprising a third bending step of bending the outer lead to approximately 90° in addition to the bending amount in the second bending step, and a curling step of bending the tip of the external lead into an arc shape inwardly.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

FIG. 3 shows a front view of a forming device for forming external leads of a semiconductor device, and FIG. 4 shows a plan view.

This forming device 10 has five press machines 10A, 10B, 10C, 10D, 1 on a base 8.
0E are arranged in a straight line. A supply mechanism 14 for supplying the lead frame 12 cut into a predetermined length is provided near the first press machine 10A, and a semiconductor device ejecting mechanism 16 is arranged in parallel to the fifth press machine 10E. .

The lead frame 12 supplied to the first press machine 10A is made by molding an IC chip and cutting it into a predetermined length. The lead frames 12 are stored in a stacked state in a magazine 14a.

14A is a magazine supply device, and a plurality of magazines 14a are stored therein. In this magazine supply device 14A, each magazine 14a is connected to a supply line M for each feed position L of the lead frame 12.
supply means (not shown)
is pushed in the feeding direction by Then, when the magazine 14a is sent to the supply position m, the magazine 1
The lead frame 12 is pushed upward by the lift device 14c located below 4a, and the uppermost lead frame 12 is sent to the feed position L by the chuck device 18. Then, when the uppermost lead frame 12 is sent, the lead frame 12 is lifted up by the thickness of one sheet by the lift device 14c. When the lead frame 12 in the magazine 14a is exhausted, the magazine 14a is sent to the upper right in FIG.
4a is sent in the opposite direction.

The lead frame 12 at the feeding position L is fed by the cylinder 20 in the longitudinal direction of the lead frame 12 (the direction in which the presses are arranged) and is supplied to the first press machine 10A.

The first press machine 10A to the fourth press machine 10
Each press machine D is provided with a conveyance mechanism that moves and supplies the lead frame 12 to each press machine. As this conveyance mechanism, a feed arm 22 is provided on the supply side and discharge side of the mold of each press machine (in addition, in the fourth press machine 10D, a feed arm 22 is provided only on the supply side). These feed arms 22 are connected to cylinders 24, respectively, and feed the lead frame 12 in synchronization. Further, the fourth press machine 10D and the fifth press machine 10E are provided with a plurality of rollers 26 arranged in pairs on both sides of the mold, and the feed rollers 26 sandwich the cradle portion 12a of the lead frame 12. It is transported by rotating.

Next, the bending process and cutting process of each of the press machines 10A to 10E will be described. Also, Figure 1 a to d
1 shows a die cross-sectional explanatory diagram showing the bending state of each process. In the first press machine 10A, the resin burr 28
, and the tie bars 26 are cut and removed (see Figure 2).

The second press machine 10B performs a cutting process of cutting the external lead 30a into a predetermined length, and a two-step bending process (a first bending process and a second bending process).

As shown in FIG. 1a, the first bending process involves leaving the tips of the external leads 30a extending horizontally (in a free state), and forming the middle part (which may include the base part).
is clamped between die 32B and knockout 34B.
Then, the tip of the external lead 30a is connected to the die 32B.
Bend it at a substantially right angle with a punch 36B along the curved surface 32a.

In the second bending process, as shown in FIG. 1B, the base of the external lead 30a is pressed between the die 33B and the knockout 35B, and the external lead 30a is bent at 45 degrees using the punch 37B and the bending surface 33b of the die 33B.

The third press machine 10C performs a third bending process.

In the third bending step, as shown in FIG. 1c, the semiconductor device 30 is supported by the die 32C, and the base of the external lead 30a is held down by the knockout 34C, and the cam mechanism (FIG. (not shown) etc. to bring the bending punch 36C into contact with the surface of the external lead 30a without slipping,
The external lead 30a is bent almost vertically by lowering it in an arc.

The fourth press machine 10D performs preliminary curling and forming curling (fourth bending step) to bend the tip of the external lead 30a into an arc shape.

In both preliminary curling and forming curling, the upper surface of the semiconductor device 30 and the base of the external lead are pressed by the part block 34D, and the bent portion 32 of the die 32D is pressed.
At step d, bend the tip of the external lead 30a into an arc. In addition, die 3 is used for preliminary curling and forming curling.
The magnitude of the curvature of the 2D bent portion 32d is different. Reference numeral 38 denotes an eject pin for ejecting the semiconductor device 30 after curling.

In the 5th press machine and 10E, lead frame 1
The semiconductor device 30 subjected to the bending process is separated from step 2.

For example, as shown in FIG.
Each cutting and bending process is performed in the fourth press machines 10A to 10D.

As described above, the semiconductor device 30 is separated by the fifth press 10E and transported onto the tray 42 by the ejection mechanism 16, for example, the robot hand 40 having the suction cups 40a. On the other hand, the cradle part 12
a is discharged to the front of the fifth press machine 10E by the feed roller 26.

(Effects of the Invention) As described above, in the bending process of the external lead, the part immediately adjacent to the bent part is clamped and supported, so that no micro-racks occur and the thickness unevenness of the surface-treated material is reduced. It never occurs. For this reason, significant effects such as being able to obtain a high quality semiconductor device are achieved.

Although the present invention has been variously explained above with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. It is.

[Brief explanation of drawings]

Figures 1 a to d are process diagrams showing an embodiment of the present invention, Figure 2 is a schematic explanatory diagram of a lead frame, Figure 3 is a front view of a forming device for bending external leads, and Figure 4 is a plan view as well. It is a diagram. 10A to 10E...press machine, 12a...cradle section, 12...lead frame, 14...supply mechanism, 16...discharge mechanism, 18...chuck device, 22...feed arm, 26...feed roller,
30...Semiconductor device, 30a...External lead, 3
2B, 32D...Die, 40...Robot hand, 42...Tray.

Claims (1)

[Claims] 1. In J-bending of an external lead of a molded semiconductor device, the middle part of the external lead is clamped from both sides to make the tip free, and the free end side is pressed to form a substantially right angle near the clamped part. a first bending step in which the base of the external lead is clamped to free the intermediate part and the tip direction of the external lead, and the vicinity of the intermediate part is pressed to bend the first part in the vicinity of the base.
a second bending step of preliminary bending at an angle within 90° in the same direction as the bending step in the bending step;
Following the bending step, the bending position in the second bending step is further bent by applying a bending punch to the external lead surface without slipping, and the third step is bent to approximately 90° including the bending position in the second bending step. A method of forming an external lead comprising a bending process and a curling process of bending the tip of the external lead inward into an arc shape.