Improving Copper CMP Topography by Dummy Metal Fill Co-Optimizing Electroplating and CMP Planarization

摘要

In this paper, we present a dummy metal fill method based on co-optimization of both ECP and CMP processes. We present the layout dependent, minimum variance algorithm that matches not only metal densities across two-dimensional tiles of layout, but also the perimeters and shapes of metal lines in each tile. Using co-optimization as the fill criterion, our algorithm effectively minimizes the metal height differences as verified by model based CMP simulations. In addition, it also renders pre-characterization of fill constraints with respect to timing and signal integrity assurance. We also show our silicon data measured on a 65nm process that sufficiently provide proof of the method.