Von Mises stress in chemical-mechanical polishing processes

In this paper we (i) describe a model for the stress distribution across a wafer during chemical-mechanical polishing, which is solved using I-DEAS (a commercial software package) and (ii) summarize the predicted effects of carrier film and pad compressibility on polishing nonuniformity. Results indicate that (i) the Von Mises stress correlates with polishing nonuniformity, while the normal stress does not correlate with the nonuniformity and (ii) CMP uniformity improves with decreasing polishing pad and carrier film compressibility.