Cu-CMP for dual damascene technology: Prestonian vs. non-Prestonian regimes of Cu removal

Dual damascene Cu (Cu2D) is increasingly becoming the process of choice for IC technology. The Cu2D manufacturing sequence includes multiple use of CM P for both dielectric planarization and for shaping Cu interconnects, there by making CMP an enabling operation. The performance of Cu-CMP has been obs erved 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, espe cially at higher pressures . Such slurries are usually referred to as press ure-sensitive slurries. This paper analyzes a general scheme for Cu removal mechanism and explores the possible reasons behind the non-Prestonian anom aly.