JPS6364901B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bonding tool, and more particularly to a bonding tool for simultaneously connecting a plurality of external leads to electrodes of an integrated circuit element.

In the manufacturing process of integrated circuit devices, it is necessary to connect lead wires to draw conductive circuits from integrated circuit elements and the like to the outside. In recent years, as a method for this connection, a gang bonding method using a tape carrier method or the like, in which a large number of leads are simultaneously bonded by thermocompression, has been adopted.

The bonding tool used for such bonding is usually a pulse heat type bonding tool. In this method, the bonding tool is made of a metal conductor, and by passing a large current through it, the tool itself generates heat due to the electrical resistance of the metal conductor, thereby supplying the heat required during bonding. It goes without saying that bonding pressure is applied to the tool by a mechanism that is applied immediately before or simultaneously with this heating.

FIG. 1 shows the shape of a conventional general bonding tool. In the figure, for example, a through hole 2 and a separation slit 3 parallel to the working surface 1 are bored in the upper part of the working surface 1 of a bonding tool that performs bonding after aligning the electrodes of an integrated circuit element and the tips of external leads. . That is, due to the through hole 2, the bonding tool tip side surface portion 4 has a minimum cross-sectional area and a maximum electrical resistance. When a current 5 is applied in such a shape, heat is generated at the maximum electric resistance portion, that is, the left and right side surface portions 4 of the tip, the working surface 1 is heated, and the heat necessary for bonding is supplied. Further, a thermocouple (not shown) for temperature control is welded slightly above the bonding surface 1, and this provides feedback to the heating power source to accurately control the temperature. The function required of such a bonding tool is that it must be able to uniformly and quickly raise the temperature of the working surface 1 of the bonding tool by 400 DEG to 500 DEG C. upon application of electricity. However, in conventional bonding tools, it is necessary to increase the electrical resistance value in order to obtain the above-mentioned high temperature, so the cross-sectional area of the tip side surface portion 4 must be reduced, and it must necessarily be processed to be thin. However, since the pressing force required for bonding increases as the number of pins increases, the bonding tool tip side surface 4 must become extremely fragile. For this reason, this cross-sectional area cannot be reduced within a certain limit. Therefore, there is a problem in that the time required to reach the set temperature is delayed and the bonding time becomes long. In addition, when the temperature of the bonding tool working surface 1 increases, the two places on the left and right of the tip side surface 4 generate the most heat, and due to the uniformity of the temperature distribution on the bonding tool working surface 1, there is some variation on each side of the front, back, left, and right. This also included problems such as the occurrence of

The present invention provides a new bonding tool that solves the problems of the conventional pulse heat type bonding tools.

That is, according to the present invention, the through holes parallel to the working surface of the bonding tool are provided symmetrically on four sides, so that the cross-sectional areas of the four sides at the tip of the tool are made equal. This is a new bonding tool.

The bonding tool of the present invention will be explained in detail below with reference to the drawings.

FIG. 2 is a perspective view of the bonding tool of the present invention. A plurality of through holes 2' parallel to the bonding tool working surface 1 are provided on the four side surfaces of the tool tip so as to equalize the cross-sectional area of the four sides of the front, rear, right and left sides. As a result, tip side corner portions 4' are formed at each corner (four locations) at the tip of the tool.

That is, according to the present invention, heat is generated at each of the four corners of the tip side corner portion 4', which has the smallest cross-sectional area, instead of the two places on the left and right of the side surface of the tip, which conventionally generate the most heat, so that the bonding tool function is improved. This shows an excellent effect on the uniformity of the temperature distribution on the surface 1. In addition, compared to conventional bonding tools, the set temperature can be reached faster than with conventional bonding tools, which means high thermal efficiency can be achieved, so the cross-sectional area of the tip of the bonding tool does not have to be made as small as with conventional bonding tools. This also results in a structure that does not reduce the mechanical strength of the bonding tool.

As described above, the through holes parallel to the bonding surface of the pulse heat type bonding tool used in the process of simultaneously bonding each electrode of an integrated circuit element to an external lead at multiple points in the present invention are formed on the four sides of the front, rear, left, and right sides of the tip of the tool. The bonding tool, which is characterized by having a plurality of bonding tools on the four sides and side surfaces so as to equalize the cross-sectional area of the parts, greatly contributes to the production of integrated circuit devices.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing a conventional bonding tool, and FIG. 2 is a schematic perspective view showing an embodiment according to the present invention. 1... Bonding tool working surface, 2, 2'...
...Through hole, 3... Separation slit, 4... Tool tip side surface, 4'... Tool tip side corner, 5...
Pulsed heat current.

Claims (1)

[Claims] 1. In a pulse heat type bonding tool used to simultaneously connect a lead and a chip electrode, a plurality of through holes are formed on the four side surfaces of the tip of the tool, which are parallel to the bonding surface of the bonding tool. A bonding tool comprising: