Synergetic effect of H2O2 and glycine on cobalt CMP in weakly alkaline slurry

Cobalt has been selected as one of the most promising candidates of barrier metals for the next-generation ultra-large scale integrated circuits. This paper investigated the synergetic effect of oxidizer like H2O2 and complexing agent like glycine on the cobalt polishing performance. It is revealed that the cobalt static etching rate (SER) and removal rate (RR) are gradually suppressed with increasing pH due to the formation of compact and passive cobalt oxides on the cobalt surface, and the addition of high concentration of H2O2 can further reduce the cobalt RR. However, by the synergetic effect of H2O2 and glycine at pH 8.00, the cobalt SER and RR can be enhanced due to the formation of soluble Co(III)-glycine complex.