JPS6135698B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wedge for an ultrasonic wire bonder that can reduce crimp misalignment defects of wires of the ultrasonic wire bonder used in the assembly process of semiconductor devices.

As shown in FIG. 1, a conventional ultrasonic wire bonder wedge has a wire guide hole 3 diagonally drilled in the shoulder of the wedge 1 toward the wire pressurizing surface 2, and the wire guide hole 3 (not shown) is inserted through the wire guide hole 3. The wire 4 pulled out from the wire spool is guided to the wire pressing surface 2, and the wire 4 is pressed by the wire pressing surface 2, and at the same time, the wire is bonded to an object such as an electronic pad or lead using ultrasonic vibration. . However, in such conventional wedges for ultrasonic wire bonders, the distance between the end of the wire guide hole 3 that guides the wire 4 and the wire pressure surface 2 is quite large, and the support point of the wire 4 is far away from the tip of the wire. Because it is far away, the wire 4 is poorly supported, making it difficult to determine the position of the wire 4, and because the wire guide hole 3 is a large hole so that the wire 4 can pass through easily, there is a lot of play, making it even more unstable. Therefore, even if the wire 4 is crimped with the wire pressure surface 2, the crimping position may shift, making it difficult to attach the wire properly and reliably, and many bonding defects occur.

The present inventor previously proposed the following technology to solve such problems.

FIG. 2 shows a perspective view of the main parts of an ultrasonic wire bonder equipped with an ultrasonic wire bonder wedge developed by the present inventor. The wire 14 is inserted into a vertically drilled hole 16a with the wedge tip 11a facing downward and fixed with a set screw 17, and is pulled out from the wire reel 18 through a hole 16b drilled in the body of the horn 16.
is guided to the wedge tip 11a. The ultrasonic energy from the oscillator 15 is transmitted to the wedge 11 via the horn 16, and the wedge 11 presses the wire 14 while vibrating and crimping it to attach the wire.

FIG. 3 is a partially omitted perspective view of the ultrasonic wire bonder wedge 11 developed by the present inventor shown in FIG. It is formed into a step-like shape, the most advanced plane thereof is the wire pressurizing surface 12, the side surface 11b immediately adjacent to this pressurizing surface 12 is tapered, and a half-moon-shaped wire guide is formed here as a part of the wire guide path. A groove 13a is formed along the side surface 11b, and one end of the groove 13a reaches the wire pressing surface 12 and bites into a part thereof.
The other end extends to the boundary between the second plane 11c and the side surface 11b, and also cuts into a part of the plane 11c. Further, the body portion 11d of the wedge 11
A wire guide hole 13 is formed in a straight line continuous with the wire guide groove 13a so that a wire 14 from a wire reel (not shown) can be guided to the wire pressurizing surface 12. In addition, the diameter of the wire guide hole 13 is set to a size commensurate with the wire diameter of the wire 14, and in order to avoid too much play between the wire guide hole 13 and the wire 14, the entrance of the wire guide hole 13 is tapered. , so that the wire 14 can be easily inserted.

In parallel to this, the wire guide groove 13a has a dimension equal to the shape of one of the two diametrically divided wire guide holes 13.
Moreover, the wire pressure surface 12 of the wire guide groove 13a
The shape of the cut-in part may be formed to be somewhat tapered as shown in FIG.

Therefore, when performing ultrasonic wire bonding on the wedge 11 having the above-described structure, first the wire 14 drawn out from the wire reel 18 shown in FIG. 1 through the hole 16b is inserted into the wire guide hole 13, and then Then, the wedge 11 is moved to a wire bonding position on an element pad or lead frame (not shown) and lowered, and the wire 14 is guided to the wire pressure surface 12. The wire is crimped by ultrasonic vibrations transmitted from the oscillator 15 via the horn 16. By the way, at the time of wire crimping, the wire 14 is guided to the edge of the wire pressing surface 12 by the wire guide groove 13a, so the wire 14 has a fulcrum at a position very close to the tip. The wire portion extending beyond that point, that is, the crimping portion, can be made to correspond to the wire pressing surface 12 without any play in both the length direction and the width direction of the wire pressing surface 12.

As is clear from the above invention, according to this technique, the wire guide path cut in the body of the wedge is extended to the wire pressure surface provided at the tip of the wedge, so that the wire can be placed extremely close to the tip. It can be supported. Therefore, unnecessary play is not created in the crimped portion such as the wire tip of the wire, and wire crimping deviation does not occur when crimping the wire, so the number of wire bonding defects caused by crimping deviation is greatly reduced. Wire bonding accuracy can be improved.

However, according to the inventor's studies, it has become clear that the above technique also has problems. That is, it has been found that in the wedges shown in FIGS. 3 and 4, since the play in the wire is relatively large, problems such as the position of the wire becoming unstable during bonding remain.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a wedge for an ultrasonic wire bonder that has a structure that does not cause wire play or crimp misalignment during ultrasonic wire bonding.

The basic structure of the present invention to achieve these objects is to supply the wire directly to the wire pressure surface through the wire guide hole drilled on the side surface of the wedge, thereby minimizing wire play and ensuring stable bonding. It is an attempt to obtain characteristics.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 is a perspective view of a wedge according to an embodiment of the present invention. In the same figure, 21 is a wedge, 11
d is the side surface of the wedge, 22 is the wire pressure surface, 23
23a is a wire guide hole, 23a is an entrance of the wire guide hole provided on the side surface of the wedge, 23b is an exit of the wire guide hole provided on the wire pressurizing surface of the wedge, 23c is a blind portion, and 24 is a bonding wire.

In this case, the entrance 23a of the wire guide hole 23 is opened in the body of the wedge 21, and the exit 23b is opened in the wire pressure surface 22, and these openings 23a, 2
3b are directly connected so that the tip of the wire 24 inserted from the inlet 23a can be immediately exposed to the outlet 23b through the blind hole 23c.

By doing this, the play in the wire 24 is reduced and it is more effective than that shown in FIGS. 3 and 4.

As is clear from the above explanation, since the wire guide hole drilled in the body of the wedge extends to the wire pressure surface provided at the tip of the wedge,
The wire can be supported very close to the tip with little play. Therefore, unnecessary play is not created in the crimped portion such as the wire tip of the wire, and the wire does not shift when crimped, so the number of wire bonding defects caused by crimping shift is reduced. Wire bonding accuracy can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional ultrasonic wire bonder wedge, Fig. 2 is a perspective view of the main part of a bonder equipped with an ultrasonic wire bonder wedge developed by the present inventor, and Fig. 3 is an explanatory diagram of a wedge for an ultrasonic wire bonder developed by the present inventor. A partially omitted perspective view of the ultrasonic wire bonder wedge, No. 4
This figure is a perspective view showing another shape of the outlet of the wire guide groove, and FIG. 5 is a perspective view showing an embodiment of the wedge according to the present invention. DESCRIPTION OF SYMBOLS 1... Wedge, 2... Wire pressure surface, 3... Wire guide hole, 4... Wire, 11... Wedge, 11a
... Tip, 11b... Side, 11c... Plane, 11d...
Body, 12... Wire pressure surface, 13... Wire guide hole, 13a... Wire guide groove, 14... Wire, 1
5...Resonator, 16...Horn, 16a...Hole, 16b
... Hole, 17... Set screw, 21... Wedge, 22... Wire pressure surface, 23... Wire guide hole, 23a... Inlet, 23b... Outlet, 23c... Blind hole, 24...
wire.

Claims (1)

[Claims] 1. Guide the wire through a wire guide hole consisting of a through hole having a wire entrance on a side surface, and place the wire under the pressurizing surface through an opening corresponding to the wire exit of the wire guide hole. 1. An ultrasonic wire bonding wedge that guides the ultrasonic wave in a side direction opposite to an entrance thereof, wherein substantially all of the opening is located on the pressurizing surface.