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. 19, 2004
Filed:
Sep. 24, 2002
Dean Tran, Westminster, CA (US);
Salim Akbany, Diamond Bar, CA (US);
Ronald A. DePace, Mission Viejo, CA (US);
William L. Jones, Inglewood, CA (US);
Roosevelt Johnson, Compton, CA (US);
Northrop Grumman Corporation, Los Angeles, CA (US);
Abstract
A relatively simple and inexpensive process for plating precious alloyed metals, such as AuSn, AuSnIn, AgSn, AuIn and AgIn. Anodes are formed from each of the metal components in the alloy and disposed in a conducting solution. The mass of each metal components is determined by Faraday's law. The target is also disposed in the conducting solution. Plating current is independently applied to each anode. The plating is conducted under an ultraviolet light sources to optimize the process. The plating alloys can be used for various purposes including attaching a semiconductor die to a substrate. Since the process does not involve exposure of the semiconductor die to a relatively high temperature for a relatively long time, the process does not pose a risk of contamination of the semiconductor by the adhesive or wax used to hold the die in place on the carrier during processing. Moreover, unlike earlier known processes which utilize epoxy, the precious alloyed metals do not wet the entire die but only the metal contact areas, thus avoiding potential short circuit to the die.