A numerical study on slurry flow with CMP pad grooves

In this study, chemical mechanical polishing (CMP) slurry flow is investigated with two pad groove patterns, circular and circular plus radial. First, slurry flow is predicted by a numerical method, and slurry velocity is analyzed by pad groove type. The streamline of the slurry flow and wall shear stress on the wafer show that the radial groove efficiently moves the slurry into the gap between the pad and the wafer, and the effect of improved slurry flow on CMP performance is verified by experimental results. The radial groove also improved process non-uniformity, and a high rotation speed combined with the radial groove improved removal rate and non-uniformity by 11.2% and 63.9%, respectively.