VON-MISES STRESS IN CHEMICAL-MECHANICAL POLISHING PROCESSES

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