Method of application of conductive cap-layer in flip-chip, COB, and micro metal bonding

Copper (Cu) is gradually replacing aluminum (Al) as the interconnect material in integrated circuits. However, a problem arises due to the fact that the top layer Cu pad does not form a good connection with the normal bonding techniques. This is mainly due to the poor quality of copper oxide formed...

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Bibliographic Details
Main Authors Ho, Kwok Keung Paul, Chooi, Simon, Xu, Yi, Aliyu, Yakub, Zhou, Mei Sheng, Sudijono, John Leonard, Gupta, Subhash, Roy, Sudipto Ranendra
Format Patent
LanguageEnglish
Published 30.04.2002
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Summary:Copper (Cu) is gradually replacing aluminum (Al) as the interconnect material in integrated circuits. However, a problem arises due to the fact that the top layer Cu pad does not form a good connection with the normal bonding techniques. This is mainly due to the poor quality of copper oxide formed on the Cu pad surface upon exposure to the atmosphere and moisture. A method of bonding a bonding element to a metal bonding pad comprises the following steps. A semiconductor structure having an exposed, recessed metal bonding pad within a layer opening is provided. The layer has an upper surface. A conductive cap having a predetermined thickness is formed over the metal bonding pad. A bonding element is bonded to the conductive cap to form an electrical connection with the metal bonding pad.