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AssigneeSGS-ATES Componenti Elettronici S.p.A.
InventorsGiulio Iannuzzi, Carlo C. deMartiis, Vittorio Del Bo, Luciano Gandolfi
Estimating the term…
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.
A method of establishing connections between a crystalline semiconductor structure and external circuitry, said semiconductor structure including a silicon body having a front surface with a plurality of disjointed contact areas and an essentially uniform rear surface, comprising the steps of:
Dependencies are inferred from the claim text.