Cu-CMP for Dual Damascene Technology: Prestonian vs. Non-Prestonian Regimes of Cu Removal

摘要

Dual damascene Cu (Cu2D) is increasingly becoming the process of choice for IC technology .The Cu2D manufacturing sequence includes multiple use ofCMP for both dielectric planarizatil)n and for shaping Cu interconnects, thereby making CMP an enabling operation. The performance of Cu-CMP has been observed to be slurry-dependent; while slurries typically exhibit the expected Prestonian behavior, i.e., a linear dependence of removal rate on pressure and speed, some slurries exhibit deviation from this linear behavior, especially at higher pres- sures. Such slurries are usually referred to as pressure-sensitiye slurries. This paper analyzes a general scheme for Cu removal mechanism and explores the possible reasons behind the non-Prestonian anomaly.