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:
Nov. 07, 2000
Filed:
Aug. 09, 1999
Roy Mark Miller, Austin, TX (US);
Bernd Maile, Stuttgart, DE;
Don A Tiffin, Austin, TX (US);
Tim Z Hossain, Austin, TX (US);
Advanced Micro Devices, Inc., Sunnyvale, CA (US);
Abstract
An improved solder bump composition and method advantageously employs a thin low-alpha layer of lead (Pb) deposited in close proximity to alpha particle sensitive devices, while ordinary (i.e., low cost) Pb is used for the bulk of the solder bump. This approach allows for reduced overall cost while still providing protection from alpha-particle induced soft errors. The low-alpha layer reduces the flux of alpha particle into devices in two ways. First, the low-alpha layer is itself essentially Pb.sup.210 free and therefore alpha particle emissions from the low-alpha layer are negligible. Second, the low-alpha layer is substantially opaque to alpha particles emitted by the ordinary Pb which includes Pb.sup.210. As a result, sensitive circuits on a semiconductor chip employing the improved solder bump are shielded from alpha particle emissions of the low-cost Pb.sup.210 -containing portion of a solder bump.