Study on reduction of micro-scratch in oxide CMP for multi-level interconnection - Investigation of mechanism for micro-scratch formation in CMP process

Chemical-mechanical polishing (CMP) has been widely accepted for the planarization of multi-layer structures in semiconductor manufacturing. Micro-scratch is the typical defect made during the CMP process, which are produced mainly because of agglomeration of slurry. Defects like micro-scratch lead to severe circuit failure, and affects yield. In this study, we described approaches to a production-worthy CMP process to prevent impact of micro-scratches on product wafer and lead to yield improvement. We have studied the effects of slurry filtration, pad cut rate of pad conditioner disks, and pad grooving design of the hard pads. By optimizing the consumables and polishing conditions, the hard pad-pad process showed 80% improvement in defectivity compared to the stack-type pad process.