Organic Residue Removal through Novel Surface Preparation Chemistries and Processes for CMP and Post CMP Applications

摘要

Copper surface passivation during the CMP process is becoming a very important area of research as it has a profound impact on the overall performance of a CMP slurry and the final defect count of the polished wafers. Benzotriazole (BTA) has been used extensively for this purpose and linked to various pCMP clean and defectivity issues. In this study a novel polymer additive is used as a BTA alternative in the step one copper CMP slurry to passivate the copper surface. The polymer additive forms a complex with the copper and copper oxides during the CMP process. The adhesion of the copper/polymer - copper oxide /polymer is greater than standard cleaning procedures can control. To address the issue of removing this passivation layer following the step 1 polish, several ATMI-ESC surface preparation products were evaluated at Clarkson University. The removal of the passivation layer is completed by a novel process in which ESC's low pH cleaning chemistry was implemented in the buff step immediately following the CMP process on the step 1 platen. The copper surface is then cleaned using an ATMI-ESC alkaline cleaning solution on a double sided cleaning module.