Technology challenges for advanced Cu CMP using a new slurry free process

We present an advantage, from the viewpoint of simplicity, in designing the chemical reaction mechanism during chemical-mechanical polishing (CMP) with a new slurry-free CMP process (Sethuraman, 1998; Fayolle et al., 1998). Cu-CMP has been widely reported as one of the leading techniques for Cu interconnect applications. Cu CMP, however, involves several issues such as Cu dishing, Cu recess, oxide erosion and oxide rounding (Steigerwald, 1997). We have previously reported the high performance of a new slurry free Cu-CMP (Matsumoto et al., 1998). Although a large number of studies have been made of Cu-CMP, little is known about the chemical reaction mechanism, since the conventional technique using slurry and a porous pad has a complex mechanism, i.e. the cohesion of abrasive particles and chemical reaction. Therefore, to solve these issues, this paper reports the mechanism and performance of a new slurry-free Cu-CMP technique. We conclude that dishing and erosion issues can be solved by means of the chemical approach in a new slurry free Cu-CMP technique