Correlation between electrical resistance and microstructure in gold wirebonds on aluminum films

Gold ball bonds attached to either pure Al films or Al films with Cu and Si additions were annealed at temperatures in the range 77-277 degrees C for periods of up to 3000 h. Electrical resistance of the bonds was measured to within +or-1 m Omega using a manual four-probe arrangement with an applied current of up to 100 mA. Nonlinear multiple regression analysis of the data produced an empirical model for the resistance increase up to 8 m Omega . The resistance increases are related to the intermetallic phases and void configurations observed.<
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