Planarization polishing for a large-sized wafer with a small tool

2^nd report : Influence of polisher flatness on polishing accuracy and control of polisher degradation

Abstract

The flatness required for the surface of a 12″silicon wafer is becoming increasingly stringent. Therefore, a single-wafer-type CMP machine with oscillation speed control has been developed to achieve high flatness over the entire surface of large-sized wafers. Here, the experimental wafer profiles corresponded to the simulations with the flatness of a polisher profile of less than 5μm. The differences in contact distance for the radius on the polisher surface were calculated to control polisher degradation. The results showed that the differences became small with co-rotation and the same rotational speed using a circular polisher and in the case of counter-rotation using a ring polisher.