Cartesian coordinate maps for chemical mechanical planarization uniformity characterization

Widely-used 49-site polar maps, although commonly used throughout the semiconductor industry, especially for chemical-mechanical planarization (CMP) often misrepresent the uniformity of polished films. This paper discusses the merits of polar maps versus Cartesian maps for evaluating CMP processes. A series of experiments show's that 52-site Cartesian maps are preferable for estimating film nonuniformity, even though Cartesian maps are prone to distorting the film edge. New tools [1] allow high-density measurements of film thicknesses. Such data sets allow the decomposition of thickness measurements into bow, taper and warp, which assists in the characterization of the CMP processes. Published by Elsevier Science S.A.