Selective copper deposition on barrier layer Ta and TaN in the presence of a copper seed layer

Abstract

Electrochemical deposition of copper on exposed barrier layer (Ta and TaN) was carried out without deposition on an existing Cu seed layer on the same substrate. This was accomplished by immersing the sample in a solution of 1 mM 1-dodecanethiol (RSH) in ethanol, where preferential adsorption of a self-assembled monolayer of RSH deactivated the copper surface. The Cu seed layer could be reactivated again by applying a negative potential pulse. Such an externally controlled reversible change in surface chemistry toward copper deposition is potentially useful for a copper seed layer repair in the fabrication of contacts and interconnects for integrated circuits. © 2003 The Electrochemical Society. All rights reserved.