A Cahn-Hilliard modeling of metal oxide thin films for advanced CMP applications

Abstract

Chemical mechanical planarization (CMP) process enables topographic selectivity through formation of a protective oxide thin film on the recessed locations of the deposited metal layer, while a continuous chemical oxidation reaction is followed by mechanical abrasion takes place on the protruding locations. This paper demonstrates a new approach to CMP process optimization in terms of analyzing the nano-scale surface topography of the protective metal oxide films and modeling their growth through a Cahn-Hilliard equation (CHE) approach as an alternative to classical nucleation theory. It is observed that the material removal rate mechanisms and the consequent planarization performance depend on the nature of nucleation of the metal oxide films, which is a function of the oxidizer concentration of the CMP slurry.