Interface characterization and evaluation of the reactive preclean process for the removal of Cu oxide in the Cu nanointerconnect process

Abstract

To fabricate a reliable device using Cu interconnect technology, it is important to form an initial pattern profile with a good sidewall surface roughness at via bottom due to barrier step coverage issues. However, if Ar sputter etch clean is used at via contact clean prior to barrier deposition, this induces a Cu redeposition on the via sidewall. This redeposited Cu can lead to the degradation by sidewall morphology and finally the reliability issues due to poor barrier step coverage. In this study, we evaluate the reactive preclean process (RPC) as an alternative technology to overcome the disadvantages of sputter clean and discuss the effectiveness of RPC on the removal of Cu oxide in Cu dual damascene interconnect. (C) 2013 Elsevier B.V. All rights reserved.