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Temperature Limiting Circuit for Gold Die Bonder

IP.com Disclosure Number: IPCOM000084861D
Original Publication Date: 1976-Jan-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Baker, MR: AUTHOR [+3]

Abstract

A circuit is described for detecting the silicon-gold eutectic bond formation in a gold die bonder, to thereby prevent excessively heating the semiconductor chip.

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Temperature Limiting Circuit for Gold Die Bonder

A circuit is described for detecting the silicon-gold eutectic bond formation in a gold die bonder, to thereby prevent excessively heating the semiconductor chip.

Fig. 1 shows the arrangement of a semiconductor package with a conventional apparatus for gold bonding a semiconductor chip 3 to the substrate 1, by passing a current through the gold preform 2 with the current supply electrodes 4 and 5.

Existing techniques for carrying out this process often times result in overheating the semiconductor chip, because variations in the size of the gold preform 2 result in variations in the amount of current which must be supplied, in order to effectively melt the preform and form the silicon-gold eutectic bond desired. For example, a smaller preform 2 might require less current to melt it and consequently, a fixed-current supply system would overheat the assembly thereby destroying the semiconductor chip 3.

Fig. 2 illustrates the current surge protection circuit which prevents the overheating of the semiconductor chip during the gold die bond melting process. Attached to terminal A of electrode 4 and B of electrode 5 is an output coil connected to the transformer 9, whose primary is connected between a 110VAC supply through the normally closed relay switch 8'' and the system on/off switch
10.

The current sensing coil 6 wrapped about the supply line to the electrode 5, supplies a rectified current through the diodes 11 to...