Selection of an oxidant for copper chemical mechanical polishing: Copper-iodate system

摘要

Diagnostic criteria were developed to elucidate the reduction mechanism of an oxidant on a copper (Cu) surface at the corrosion potential. The corrosion potential of Cu was measured for various pH and iodate (IO_3~-) concentrations using the rotating disk electrode technique. According to the measured corrosion potentials, IO_3~- was an effective CMP oxidant only below pH 3. Application of the diagnostic criteria on the Cu - IO_3~- system showed that the reduction of IO_3~- on Cu was under the mixed kinetic and diffusion control at the corrosion potential below pH 3. Above pH 3, however, the anodic process dominated over the cathodic process.