Correlation of Polishing Pad Property and Pad Debris on Scratch Formation during CMP

Abstract:
The formation of scratches on silicon dioxide surfaces during chemical mechanical planarization (CMP) is a critical issue in semiconductor manufacturing, as it adversely affects the yield and reliability of the process. In this study, the effect of pad surface roughness and pad debris induced by various types of diamond conditioner during CMP process and scratch forming behavior were evaluated. The pad is conditioned with the diamond conditioner to provide consistent performance and to prevent the glazing effect. Five types of diamond conditioners having different diamond grade number (shape factor) and diamond density were used to condition the polyurethane pad. During conditioning process using low density and sharp diamond conditioner, the roughness and wear rate of the pad was found to be higher with higher removal rate. The scratch generation behavior showed a similar trend like removal rate. In addition, the amount of pad debris generated and pad roughness on scratch formation was evaluated through the in-situ/ex-situ conditioning. Keywords: CMP, polishing pad, scratch, wear rate, pad debris