Acceleration effect of CuCN in Ag electroplating for ultralarge-scale interconnects

Abstract

The addition of CuCN accelerated the deposition rate in cyanide-based Ag electroplating. The catalytic effect came from the high-order complexation of Cu with the free CN- ions in electrolyte. It changed the equilibrium state of the electrolyte, presented as an increase in the amount of Ag (CN)(2)(-) compared to Ag (CN)(3)(2-). Because Ag (CN)(2)(-) could be reduced more easily, Ag electroplating was accelerated. Fourier transform infrared analysis showed the equilibrium change with the increase in Ag (CN)(2)(-) peak according to the CuCN addition. For superfilling, it is necessary to localize the complexation on the Cu surface. (C) 2007 The Electrochemical Society.