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:
Jun. 10, 2003
Filed:
Apr. 11, 2001
Hong Yang, San Diego, CA (US);
Laxminarayan Sharma, San Diego, CA (US);
Applied Micro Circuits Corporation, San Diego, CA (US);
Abstract
A system and method have been provided for removing high lead content solder balls from the surface of a circuit package for the purpose of rework. The invention is applicable to ball grid array (BGA), C balls, chip scale balls, and flip chip bumps. Advantageously, the room temperature solder ball rework procedure minimizes damage to the circuit package. Specifically, a thin-film stainless steel mask with openings to expose the solder balls, is formed over the circuit package, and the solder balls are removed in a shearing or grinding operation, leaving a solder ball residue. Then, a conventional thick mask film is formed and a solder paste is deposited to fill the apertures. The solder ball residue forms a wettable surface for the low temperature attachment of new solder balls.