A study of AlCu (1%) sputter deposition parameters on electromigration

This work investigates the impact of deposition parameters on thin film quality of an AlCu/TiW metallization system. A statistically designed experiment was conducted to study aluminum deposition temperature, pressure, power, and underlying dielectric stress. Determination of Median Time to Failure (MTF) by electromigration stress was used to determine the optimum deposition parameters. Data on microstructure, as characterized by TEM and resistivity ratio (RR) measurements made on patterned conductors, are compared to the observed MTF's. Substrate temperature during deposition was found to have the most significant impact on electromigration. No correlation of MTF to RR measurements was observed. The improved EM performance at low temperature is believed to be due to a more uniform distribution and a larger number of (-)-Al/sub 2/Cu precipitates.<
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