Wire bonding to dual metal covered pad surfaces

The invention relates to wire bonding to bond pads on semiconductor chip packages and in particular to bond pads which have been coated with palladium. Wire bonds are made to palladium coated bonded pads on organic dielectric substrates at temperatures below 200° C. A layer of palladium thicker than...

Ausführliche Beschreibung

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Bibliographische Detailangaben
Hauptverfasser: Cutting, Lawrence Richard, Gaudiello, John Gerard, Matienzo, Luis Jesus, Murdeshwar, Nikhil Mohan
Format: Patent
Sprache:eng
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Beschreibung
Zusammenfassung:The invention relates to wire bonding to bond pads on semiconductor chip packages and in particular to bond pads which have been coated with palladium. Wire bonds are made to palladium coated bonded pads on organic dielectric substrates at temperatures below 200° C. A layer of palladium thicker than 14 micro-inches is covered with a thin flash of gold. Palladium coated over copper pads is protected from copper diffusion by a thin nickel layer positioned between the two. Subsequent baking for 1 hour at 185° C. drives off hydrogen molecules provided the gold is less than 200 thick. A bonding wire, preferably of gold is then successfully bonded to the pad using conventional bonding equipment at temperatures below 200° C.