SIMULATION OF CUTTING LOCUS AND OVERLAP CUTTING BY DIAMOND DRESSING IN CMP PROCESS

Diamond dressing plays a role in regenerating the polishing pad surface during Chemical Mechanical Planarization/Polishing process (CMP). The diamond dresser has many diamond grits distributed on the flat metal surface. During diamond dressing, cutting locus (CL) and overlap cutting points (OP) of diamond grits are created on the pad surface. Expectation of diamond dressing is that CL and OP must be covered all the pad surface and maintain soften, flatten and roughness of the polishing pad. This paper aims to apply a kinematic model and then propose a method for setting speeds for diamond dressing process on the current configuration of CMP tool. Prediction of CL and OP is implemented based on three main factors as rotational speed of pad, rotational speed on dresser and oscillation of dresser. It found that properly choose the speed of pad and speed of dresser can regenerate uniformity of pad surface with welldistributed CL and less OP density. This result can be applied to optimization CMP process.