Investigation of Co surface reaction by in situ measurement for chemical mechanical planarization and post-chemical mechanical planarization cleaning

Co is one of the candidates for a new material in the advanced generation of LSI. However, it is difficult to implement a precise analysis of surface reactions because a Co surface is unstable. In chemical mechanical planarization (CMP) and post-CMP cleaning, many surface reactions are simultaneously induced such as dissolving Co by a chelating agent. adhesion of an inhibitor, and oxidation of a Co surface. Those reactions should be controlled to establish the ideal processes of CMP and post-CMP cleaning. In this work, we performed open circuit potential (OCP) monitoring and succeeded in tracing the complicated reactions. It enabled us to compare the strengths of inhibitors and select appropriate inhibitors in a post-CMP cleaner. The measurement and analysis can be applied to not only post-CMP cleaning but also CMP. (C) 2018 The Japan Society of Applied Physics