The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 05, 1993
Filed:
Jul. 16, 1992
Applicant:
Inventors:
Michael F Brady, Morrisville, PA (US);
Rajan D Deshmukh, Yardley, PA (US);
Assignee:
AT&T Bell Laboratories, Murray Hill, NJ (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B23K / ; B23K / ;
U.S. Cl.
CPC ...
22818022 ; 228223 ;
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.