Abstract
A novel polishing pad system and machine were designed and developed to perform a uniform removal rate for a whole wafer surface in CUP (Chemical Mechanical Polishing) planarization process. The pad materials which are composed of hard and soft two layers, and the dimensions were designed based on the calculation of polishing pressure distribution by FEM. The CMP machine developed has good and original features of the followings: Five wafers which are chucked on high precision and rigid stages are simultaneously polished rotating with planetary motion The wafers surface to be polished are set with up and the pad surface is determined by the five wafers envelope. The hard pad which practices the wafer surface polishing do not attached on platen, but are stretched from the periphery of the platen. Using this CMP system, the polishing pressure distribution was measured and calculated for whole wafer area in static state. Then the wafers on which have oxide film were actually polished and the removal rate distribution of the wafers were measured. The actual surface profile corresponds well to the measured and calculated pressure profile. It is found that the removal rate distribution of a wafer is controllable from the center-fast to center-slow by using the base-plate which has different radius under the pad system.
