Metal fusion bonding – Process – Plural joints
Patent
1992-07-16
1993-10-05
Heinrich, Samuel M.
Metal fusion bonding
Process
Plural joints
228223, B23K 100, B23K 3538
Patent
active
052497330
ABSTRACT:
A solder self-alignment process for aligning a semiconductor chip (13) with, and bonding the chip to, a substrate (12) is preformed in an atmosphere rich in gaseous formic acid, at least during the melting step. It is preferred that the formic acid atmosphere be maintained during the self-alignment step and the step of cooling and hardening the solder elements (23). With this feature, one can completely avoid the use of any solid or liquid fluxes and avoid the consequences of such use. Nonetheless, the molten solder elements (23) dependably bond to the bonding surfaces and vertically align themselves.
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Brady Michael F.
Deshmukh Rajan D.
Anderson R. B.
AT&T Bell Laboratories
Heinrich Samuel M.
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