JPH0719867B2 - External lead molding method for resin-sealed semiconductor device - Google Patents

Description

The present invention relates to an external lead molding method for a resin-sealed semiconductor device having gull-wing external leads such as QFP type and SOP type.

[Prior Art] Conventionally, a gull wing type outer lead having first and second curved portions obtains a predetermined outer lead shape by one downward movement of an upper die of a lead forming die.

5A to 5C are cross-sectional views showing a method of forming a gull wing type external lead of a conventional semiconductor device in the order of steps.

As shown in FIG. 5 (a), a resin-sealed semiconductor device 10 has a resin-sealed portion 1 in which a semiconductor chip is sealed and external leads 2 that project laterally from the resin-sealed portion 1. . The die 6 as the lower die of the lead molding die has a convex portion that supports the external lead 2 without contacting the resin sealing portion 1.
Further, the upper die 4 of the molding die is disposed above the die 6 and has a pad 4a facing downward at the edge thereof. A rectangular cylindrical bending punch 7 is arranged so as to surround the upper die 4.
The pad 4a and the bending punch 7 are individually moved up and down by a driving device (not shown). The semiconductor device 10 is mounted with the base end portion of the outer lead 2 on the resin sealing portion 1 side in contact with the convex portion of the die 6.

Next, as shown in FIG. 5B, when the upper die 4 is lowered from above the semiconductor device 10, the semiconductor device 10 causes an external lead between the convex portion of the die 6 and the pad 4a of the upper die 4. It is fixed by sandwiching the base end of 2.

Next, as shown in FIG. 5C, the bending punch 7 is lowered along the side surface of the upper die 4. This enables semiconductor devices
Ten outer leads 2 are bent into a gull-win type. After that, the upper die 4 and the bending punch 7 are sequentially lifted to complete the forming process of the outer lead 2.

[Problems to be Solved by the Invention] However, in the resin-encapsulated semiconductor device, the resin-encapsulated portion 1 is likely to warp due to internal strain stress or the like when the resin is solidified. Thus, in the above-described conventional external lead molding method, since the base end portion of the external lead 2 of the semiconductor device 10 on the resin sealing portion side is strongly sandwiched and fixed by the pad 4a and the die 6, the resin sealing is performed. The outer lead 2 is molded while the warp of the portion 1 is corrected. Therefore, when the upper die 4 is lifted after lead molding and the semiconductor device 10 is released from the restraining force of the molding die, the warp of the resin sealing portion 1 returns to the state before lead molding, that is, before correction, and 6 (a),
As shown in (b), the resin sealing portion 1 is warped again. Therefore, the array shape of the external leads 2 after the molding of the semiconductor device 10 changes in accordance with the warp of the resin sealing portion 1.

6 (a) and 6 (b) are QFPs in which the resin sealing portion 1 has a warp.
1 shows a state in which the semiconductor device 10 is mounted on a printed circuit board after the semiconductor device has been lead-molded. As described above, due to the change in the array shape of the external leads 2,
The soldering surface 3 is not in full contact with the printed circuit board. Therefore, in the conventional lead forming method, the arrangement accuracy of the soldering surface 3 of the outer lead 2 in the same plane is low. Therefore, there is a significant inconvenience when the semiconductor device 10 is mounted on the printed circuit board by soldering. Quantitatively, the warpage is 0.1m
In a semiconductor device having a length of m or more, all the leads cannot be correctly soldered in the subsequent soldering and mounting process.

The present invention has been made in view of such problems,
External lead molding of a resin-encapsulated semiconductor device that can improve the solderability of the external leads by improving the in-plane alignment accuracy of the soldering surface of the external leads even in a semiconductor device having a warp in the resin encapsulation The purpose is to provide a method.

[Means for Solving the Problem] The external lead molding method for a resin-encapsulated semiconductor device according to the present invention uses the first die for the external lead protruding from the resin-encapsulated portion of the resin-encapsulated semiconductor device. A step of forming a first bent portion by bending a portion of the base end side, and a step of forming the first bent portion by sandwiching the semiconductor device only at a central portion of the resin sealing portion and fixing the semiconductor device by the second mold. And a step of forming a second curved portion by bending the tip end side portion of the lead.

[Operation] In the present invention, first, the base portion of the outer lead on the resin sealing portion side is bent by the first mold to form the first bent portion, and then the semiconductor device is sealed with the resin. Only the central part of the stopper is sandwiched and fixed, and the second mold is used to bend it.
Mold the curved part of to make the soldering surface.

In this way, the bending process of the soldering surface of the external leads is performed by sandwiching and fixing only the central part of the resin encapsulation part, and not fixing the external leads. Since it is processed, it is possible to arrange all the soldering surfaces in a predetermined same plane with high accuracy without being affected by the warp of the resin sealing portion of the semiconductor device.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIGS. 1A to 1E are sectional views showing a first embodiment of the present invention in the order of steps.

First, as shown in FIG. 1 (a), the lower die 16 of the first molding die has a convex portion for supporting the external lead 2 at the edge thereof. Further, the upper die 4 of the molding die is disposed above the die 16, and a downward pad 4a is provided on the edge portion thereof. Then, a pair of bending rollers 5a provided on the side surface of the upper die 4 so as to sandwich the upper die 4 are arranged in two sets with their axial directions orthogonal to each other (a pair of bending rollers in FIG. 1).
Only 5a is shown). Each pair of bending rollers 5a is freely rotatable and rolls on a pair of side surfaces of the upper die 4 and the lower die 16 which are parallel to each other, and is vertically moved by an appropriate driving device. Further, the upper die 4 moves up and down independently of the bending roller 5a by a driving device (not shown). Semiconductor device 10
Is placed with the resin sealing portion side base end portion of the external lead 2 in contact with the convex portion on the die 16 of the first molding die.

Next, as shown in FIG. 1 (b), the upper die 4 is lowered to sandwich the base end portion of the external lead 2 between the convex portion of the die 16 and the pad 4a, so that the semiconductor device 10 is formed. Fix it.

Next, as shown in FIG. 1 (c), the bending roller 5a is lowered along the side surfaces of the upper die 4 and the die 16 as indicated by the arrow. As a result, as shown in FIG. 2, the outer lead 2 is subjected to the first bending work so as to follow the side surface of the die 16.
FIG. 2 is a view showing the shape of the external leads 2 of the resin-sealed semiconductor device which has finished the first bending process.

Next, the semiconductor device 10 is moved to the second position by a carrier device (not shown).
To the lead molding die.

As shown in FIG. 1 (d), this second lead molding die has a rod-shaped second pad 8 whose upper end surface is flat, on which resin molding of the semiconductor device 10 is performed. Place part 1. Further, above the second pad 8, a second die 9 having a downward convex portion in the central portion is arranged. The second die 9 moves up and down by an appropriate driving device (not shown), and when it descends, the central portion of the resin sealing portion 1 of the semiconductor device 10 is placed between the central convex portion and the pad 8. Hold and fix. The bending roller 5b, which can be freely automated, is driven by a driving device (not shown) to move in the horizontal direction.

Then, as indicated by the arrow in FIG. 1 (e), the bending roller
5b moves in a direction away from the pad 8, whereby the external lead 2 is secondly bent so as to follow the lower surface of the second die 9 and the soldering surface 3 is formed.

As shown in FIGS. 3A and 3B, the external leads of the resin-encapsulated semiconductor device molded according to this embodiment have the same external leads 2 regardless of whether or not the resin-encapsulated portion 1 is warped. The soldering surface 3 has high in-plane alignment accuracy. Further, since the outer lead 2 is bent by rolling the rotatable bending rollers 5a and 5b, the surface of the outer lead 2 is not rubbed by a punch or the like. Therefore, there is an advantage that damage to the surface of the external lead such as peeling of solder plating can be minimized.

Next, a second embodiment of the present invention will be described.

FIGS. 4A to 4E are sectional views showing the second embodiment of the present invention in the order of steps.

First, as shown in FIG. 4A, the lower die 26 of the first molding die has a convex portion for supporting the lead 2 at the edge portion. Further, the upper die 4 of the molding die is disposed above the die 26, and the pad 4a facing downward is provided at the edge portion thereof. Also, a bending punch 7a having a rectangular tubular shape so as to surround the upper die 4
Is provided. The upper die 4 is a drive device (not shown)
The bending punch 7a is vertically moved by the drive device as shown by an arrow in FIG. 4 (c). The semiconductor device 10 is the die of the first molding die configured as described above.
The convex portion 26 is placed with the base end portion of the outer lead 2 on the resin sealing portion side in contact.

Next, as shown in FIG. 4B, the upper die 4 is lowered to sandwich the base end portion of the external lead 2 between the convex portion of the die 26 and the pad 4a, so that the semiconductor device 10 is formed. Fix it.

Next, as shown in FIG. 4 (c), the bending punch 7a is obliquely lowered as indicated by the arrow. By the bending punch 7a, the external lead 2 is first bent so as to follow the side surface of the die 26.

Next, the semiconductor device 10 is transported to the second lead molding die by a transport device (not shown).

As shown in FIG. 4 (d), the second lead molding die has the second die 9 and the second pad 8 as in the case of the first embodiment, but in the present embodiment, , Bending roller 5b
A bending punch 7b is provided instead of the above. Bending punch 7b
Is driven by a driving device (not shown) in a substantially horizontal direction and a direction in which it rises slightly as it moves away from the pad 8, as shown in FIG. 4 (e). Semiconductor device 10
Is fixed by sandwiching the central portion of the resin sealing portion 1 from above and below by the second pad 8 and the convex portion at the central portion of the second die 9.

Then, as shown by the arrow in FIG. 4 (e), a bending punch is used.
7b moves to the outside, whereby the external lead 2 is subjected to the second bending work in a shape following the lower surface of the second die 9 to form the soldering surface 3.

In this way, as in the first embodiment, the molding of the external leads 2 having a high level of coplanar arrangement accuracy between the soldering surfaces 3 of the external lid 2 is completed.

In this embodiment, since the outer lead 2 is bent by the plane portions of the die 26, the bending punch 7a, and the second die 9 and the bending punch 7b, the bending portion has a small curvature, that is, a lead having a sharp shape. It has the advantage that it can be molded.

[Effect of the Invention] As described above, according to the present invention, the bending process of the base end portion and the bending process of the tip end portion of the external lead of the resin-encapsulated semiconductor device are individually performed in separate steps. As a result, the soldering surface of the external leads can be bent without correcting the warp of the resin-encapsulated portion of the resin-encapsulated semiconductor device. It can be arranged with high precision. Therefore, there is an effect that it is possible to avoid defective soldering due to warpage of the resin-encapsulated portion of the resin-encapsulated semiconductor device.

[Brief description of drawings]

1 (a) to 1 (e) are sectional views showing a first embodiment of the present invention in the order of steps, FIG. 2 is a perspective view showing a lead forming state during the same step, and FIG. 3 (a) is a sectional view. Similarly, a perspective view showing a state in which the lead forming is completed, FIG. 3 (b) is a sectional view of the same, and FIGS. 4 (a) to 4 (e) are sectional views showing a second embodiment of the present invention in process order. FIG. 5 is a cross-sectional view showing a conventional gull wing type external lead forming method for a resin-sealed semiconductor device in the order of steps, FIG. 6 (a) is a perspective view showing the same lead forming state, and FIG. 6 (b). Is a sectional view of the same. 1; Resin sealing part, 2; External lead, 3; Soldering surface, 4; Upper mold, 4
a; pads, 5a, 5b; bending rollers, 6, 16, 26; dies, 7, 7a, 7b;
Bending punch, 8; second pad, 9; second die, 10; semiconductor device

Claims (1)

[Claims] 1. A step of forming a first bent portion by bending a portion of a base end side of an external lead protruding from a resin-sealed portion of a resin-sealed semiconductor device with a first die. A step of forming a second curved portion by bending the tip end side portion of the external lead with a second mold in a state in which only the central portion of the resin sealing portion is sandwiched and fixed in the semiconductor device, An external lead molding method for a resin-encapsulated semiconductor device, comprising: