Optimization of post-CMP cleaning process for elimination of CMP slurry-induced metallic contaminations

We have invetigated the slurry-induced metallic contaminations of undoped a nd doped silicate oxide surface during the post-chemical mechanical polishi ng (CMP) cleaning process. The metallic contaminations by CMP slurry were e valuated in the four different oxide films, such as plasma enhanced tetra-e thyl-ortho-silicate glass (PE-TEOS), O-3-boro-phospho-silicate glass (O-3-B PSG), PE-BPSG, and phospho-silicate glass (PSG). Prior to entering the post -CMP cleaner, all films were polished with KOH-based slurry. The total X-ra y fluorescence (TXRF) measurements showed that all oxide surfaces are heavi ly contaminated by potassium and calcium during polishing, which is due to the CMP slurry. The polished O-3 BPSG films presented higher potassium and calcium contaminations compared to PE-TEOS film because of a mobile ion get tering ability of phosphorus. For PSG oxides, the slurry-induced mobile ion contamination increased with an increase of phosphorus content. In additio n, the polishing removal rate of PSG oxides had a linear relationship with phosphorus content. (C) 2001 Kluwer Academic Publishers.