Current Induced Grain Growth of Electroplated Copper Film

To study the potential of electric current stress in enhancing the grain growth of electroplated copper (Cu) films, the behavior of Cu grain growth at different additive concentrations with current stress applied was investigated. It was found that the lower poly(ethylene glycol) (PEG) concentration alone slightly enhanced the grain growth, but the higher sulfopropyl sulfonate (SPS) concentration was favored in assisting larger grain growth in the current induced grain growth. The effect of current density and temperature on the current induced grain growth have also been studied, and it was found that current stress with a high current density and at a high temperature promotes a larger grain size and anisotropic grain growth along the current direction. (C) 2012 The Japan Society of Applied Physics