Metal fusion bonding – Process – Plural joints
Patent
1992-07-01
1994-02-15
Bradley, Paula A.
Metal fusion bonding
Process
Plural joints
228 45, 228205, B23K 3102
Patent
active
052859495
ABSTRACT:
The present invention relates to a wire bonding method and a wire bonding apparatus employing a coated wire in which the surface of a metal wire is coated with an insulator, and a semiconductor device produced by the bonding method. The present invention includes forming a mixed gas of (1) a combustible gas and (2) a temperature controlling gas for lowering the combustion temperature of the mixture; and removing the insulator coating material from the coated wire at a bonding part of the coated wire, so as to denude the surface of a metal wire, by the use of flames produced by the combustion of the combustible gas of the mixed gas. The removal of the insulator is executed by an insulator removal torch. Also, the present invention includes forming a metal ball on the front end of a coated wire; joining the metal ball to an external terminal of a semiconductor chip; bringing the rear end of the coated wire into contact with an external lead and destroying the insulator coating where the coated wire contacts the lead; and joining the metal wire at the rear end of the coated wire to the lead. According to the above-stated expedients, the combustion flames, which do not impose any damage or breakdown on the metal wire, can be turned around substantially the whole area of the bonding part of the coated wire, so that the insulator of the coated wire can be readily removed to lessen bonding defects. Moreover, the melting and shrinking insulator of the coated wire is blown away, and insulator globes can be prevented from being formed in the coated wire, so that the bonding defects are avoidable.
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Okikawa Susumu
Tanimoto Michio
Bradley Paula A.
Hitachi , Ltd.
Mah Chuck Y.
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