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:
Sep. 03, 2002
Filed:
Aug. 18, 2000
Pedro Armengo Chalco, Yorktown, NY (US);
Edmund David Blackshear, Wappingers Falls, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method is provided for forming a solder joint to a pad, in which the thickness of the intermetallic layer formed by nickel in contact with solder is significantly reduced. A first layer of nickel is provided on the pad; a second layer of a noble metal (preferably gold) is then provided overlying the first layer. The first layer and the second layer are then annealed, thereby forming an alloy layer including nickel and the noble metal between the first layer and the second layer. Contacting the second layer with a molten solder (where the solder includes tin) then causes the noble metal to dissolve in the solder and the solder to subsequently wet the alloy layer, forming an intermetallic layer including nickel, the noble metal and tin. Only a thin intermetallic film grows, thus improving the reliability of the solder joint.