JPH0646646B2 - Wire bonding equipment for semiconductor device assembly - Google Patents

Description

The present invention relates to a wire bonding apparatus for assembling semiconductor devices.

[Conventional technology]

Conventionally, a feeder of a wire bonding apparatus for assembling a semiconductor device of this type is index-feeded one by one with a lead frame, and a hole for the index feed is provided around the lead frame for relative positioning with the device. Positioning holes are provided. The lead frame is generally positioned by inserting a tapered positioning pin into the positioning hole to determine the position of the lead frame.

FIG. 3 and FIG. 4 show an example of a conventional wire bonding apparatus. As shown in FIGS. 3 and 4, the feed claw 1 moves up and down and is inserted into the square hole 2 to feed the lead frame 6 in the direction of the arrow 3 along the guide rail 9. At this time, the tapered positioning pin 4 is at the bottom, but at the same time when the feeding of the lead frame 6 is completed, the positioning pin 4 rises and is inserted into the positioning circular hole 7 to position the lead frame 6 and the heater plate 5 The lead frame is heated to start the wire bonding of the semiconductor element 8, and thereafter this series of operations is repeated.

[Problems to be solved by the invention]

However, in such a conventional apparatus, when a lead frame made of a material having a large thermal expansion is flowed, the distance between the positioning round holes and the distance between the feed angle holes are 11 depending on the difference in the material thermal conductivity and the thermal expansion coefficient of the lead frame 6. Obviously, the feed accuracy deteriorates and the yield decreases.

Also, in the case of a lead frame made of a copper-based material, only the portion in contact with the heater plate 5 is heated,
Partially thermally expands. On the other hand, since the portion not in contact with the heater plate 5 does not expand so much, the lead frame 6
Thermal stress is generated inside, causing deformation, which makes bonding impossible at all, or deformation after bonding causes wire breakage.

Particularly, when the semiconductor element 8 is heated and this heat is conducted to the tab lead 15 of the lead frame 6, the tab lead 15
Thermally expands, and its length becomes longer than the length 12 of the lead frame 6 in the width direction. Since both ends of the tab lead 15 are integrally connected to the lead frame 6, the tab lead 15 is deformed by thermal expansion and warped. Since the semiconductor element 8 is supported by the tab lead 15, when the tab lead 15 is warped, the semiconductor element 8 floats up, or when the tab lead 15 is extremely thin, the arrow 1
As described in 3, the semiconductor element 8 rotates to cause the positional deviation, and the thermal expansion of the tab lead 15 is absorbed. Therefore, the positional deviation of the wire bonding occurs and the yield is deteriorated.

An object of the present invention is to provide a wire bonding apparatus for assembling a semiconductor device which suppresses deformation of a lead frame and performs good wire bonding.

[Means for solving problems]

The present invention positions the lead frame islands, which are index-fed one frame at a time, at the bonding processing position,
In a wire bonding apparatus for assembling a semiconductor device, wherein the island of the lead frame is heated by a heater plate and a semiconductor element on the island is wire-bonded, a cooling unit that cools the outer periphery of the lead frame along the feed direction of the lead frame. And cut the heating surface of the heater plate corresponding to the tab lead of the lead frame, install the heater plate at the bonding processing position, and install the heater plate for preheating at a position corresponding to the island in front of it. The wire bonding apparatus for assembling a semiconductor device is characterized by the above.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

1 and 2, the device of the present invention is provided with a pipe 14 along the feed direction of the lead frame 6, and the lead frame 6 is cooled by blowing dry air or a gas such as N ₂ from the pipe 14. Since the outer periphery of the lead frame 6 is cooled by the gas, it is maintained at a constant temperature. Therefore, since the distance between the positioning round holes and the distance between the feeding square holes are not changed, the feeding accuracy is significantly improved, and the yield is improved.

Further, the bonding heater plate 5 is not rectangular, but the plate 5 directly below the tab lead 15 of the lead frame 6.
The heating surface 5a is cut and cut. Although the plate was cut to cut off the plate heating surface 5a immediately below the tab lead, the plate is not limited to this and may be concave.

In the present invention, since the heating surface of the plate 5 does not exist directly under the tab lead, the tab lead 15 is not heated and the tab lead 15 is not heated.
Is not deformed due to thermal expansion, and the length of the tab lead 15 is suppressed within the range of the length 12 in the width direction of the lead frame 6, so that the semiconductor element 8 does not float or rotate, which is favorable. It is possible to do various bodywork. Further, at least one heater plate 5 having the same structure as the heater plate 5 is provided in front of the bonding portion.
It is installed for heating the semiconductor element 8 immediately before, and a temperature gradient is applied to this to lower the temperature of the semiconductor element part one before the bonding part, so that the entire lead frame 6 is gradually heated and the entire lead frame 6 is Heat to a uniform temperature. Therefore, since the thermal stress of the entire lead frame 6 is softened, it is possible to feed and bond the lead frame satisfactorily without being deformed into a curved shape.

〔The invention's effect〕

As described above, according to the present invention, the outer periphery of the lead frame in the feed direction is cooled by gas, the bonding Peter plate preheats at least one semiconductor element before the bonding position, and the tab lead is prevented from being heated. By cutting the heating surface of the bonding heater plate corresponding to the tab lead and providing a temperature gradient to the bonding heater, the feed accuracy of the lead frame is improved, and deformation of the lead frame is prevented, and good bonding can be achieved.

[Brief description of drawings]

1 is a plan view showing a wire bonding apparatus of the present invention, FIG. 2 is a sectional view showing a wire bonding apparatus of the present invention, FIG. 3 is a plan view showing a conventional wire bonding apparatus, and FIG. It is sectional drawing which shows a wire bonding apparatus. 1 ... Feed, 2 ... Square hole, 4 ... Positioning pin, 5
...... Heater plate, 6 ...... Lead frame, 7 ......
Round hole, 8 …… Semiconductor element, 9 …… Guide rail, 10 ……
Between positioning holes, 11 ... feed angle hole, 12 ... lead frame width direction, 14 ... pipe, 15 ... tab lead

Claims (1)

[Claims] 1. A semiconductor device in which an island of a lead frame, which is index-fed one frame at a time, is positioned at a bonding processing position, and the island of the lead frame is heated by a heater plate while wire bonding processing is performed on a semiconductor element on the island. In the wire bonding apparatus for assembly, a cooling unit is installed to cool the outer circumference of the lead frame along the feed direction of the lead frame, and the heating surface of the heater plate corresponding to the tab lead of the lead frame is cut and the heater plate is bonded. A wire bonding apparatus for assembling a semiconductor device, wherein the heater plate is installed at a position corresponding to an island in front of the heater plate for preheating.