Development of CMP slurry for FEOL process

In chemical mechanical planarization (CMP) processes for semiconductor devices, more than one materials may appear as the polishing progresses. In the slurries for front end of line (FEOL) processes, removal rate (RR) enhancement for dielectric layer (silicon oxide, silicon nitride) and etching rate (ER) inhibition for plug materials (W and poly-Si) are needed. In this study, we designed a novel slurry for FEOL processes. The key factors were i) suppression of ERs by pH control, ii) suppression of RRs for poly-Si by additive control, and iii) enhancement of RRs for silicon nitride by additive control.