Mapping wafer flatness changes in chemical mechanical planarization

This paper discusses the feasibility of using non-contact capacitive gauging technology for wafer flatness characterization in Chemical Mechanical Planarization (CMP). A simple but efficient method is introduced which provides guidance for CMP wafer flatness qualification per advanced lithography requirements. The statistical analysis quantitatively explains why CMP is an enabling technology for surface planarization in sub-half micron or less technologies. A gain of approximate 7% in terms of site flatness improvement at 0.18 μm technology is observed which represents a significant yield improvement from a lithographic perspective