Reduction of resistivity of electroplated copper by rapid thermal annealing

Abstract

Reduction of resistivities of copper films, electroplated by superior electrolytes with capabilities of gap filling sub-150 nm damascenes, was demonstrated to be below 2.1 muOmega cm by rapid thermal annealing at 400degrees C in 30 s. In as-deposited copper films, the charge transfer polarization resistances and the incorporation effects of additives determined their resistivity and the dosage of impurities. In addition, the activation energy for grain growth slightly increased from similar to0.33 eV for additive-free electrolytes, to similar to0.4 eV for the superior electrolytes, and the process time was significantly shorter than several hours in conventional furnace processes. (C) 2002 The Electrochemical Society.