Evaluation of pad groove designs under reduced slurry flow rate conditions during copper CMP

The main objective of this investigation is to verify if "smart" groove designs can increase slurry utilization, by controlling the amount of slurry transferred from the pad grooves to the land area-wafer interface, resulting in process optimization. Based on previous studies concerning Logarithmic-Spiral as well as Concentric Slanted grooves, two groove designs were selected to be evaluated and compared to the popular industrial groove design (concentric grooves) under reduced slurry flow rate conditions during copper polishing. The effect of several process parameters were investigated, including pad groove design, applied wafer pressure, and slurry flow rate. Theoretical examination of the experimental data was performed by applying a three-step copper RR model, in order to establish the effect of groove designs on the chemical and mechanical mechanisms present during copper chemical mechanical polishing (CMP).