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:
Dec. 04, 1979
Filed:
Nov. 03, 1978
Giulio Iannuzzi, Milan, IT;
Carlo C deMartiis, Milan, IT;
Vittorio Del Bo, Monza, IT;
Luciano Gandolfi, Corsico, IT;
SGS-ATES Componenti Elettronici S.p.A., Agrate Brianza, IT;
Abstract
A silicon wafer, having a front surface with disjointed contact areas and a uniform rear surface, is provided at the contact areas of its front surface with respective pads each comprising a base layer of aluminum, a first intermediate layer of chromium or titanium, a second intermediate layer of nickel and an outer layer of gold or palladium. The rear surface is covered with a base layer of gold (or of a gold/arsenic alloy in the case of N-type silicon), a first intermediate layer of chromium, a second intermediate layer of nickel and an outer layer of gold or palladium to which a film of low-melting bonding agent (lead/tin solder) is applied. After testing and elimination of unsatisfactory wafer sections, the remaining sections are separated into dies placed on a conductive substrate; an extremity of a respective terminal lead, encased in a similar bonding agent, is then placed on the outer layer of each contact pad. All soldering operations are simultaneously performed in a furnace.