Two defects that arise from the polishing process in integrated circuits technology are erosion and dishing.  In this manuscript a generic numerical-model that is capable of describing these defects from a mechanics perspective is presented.  This numerical-model formulates evolution of surface shape for an initially flat sample made up of two distinct materials with different wear rates under constant average polishing pressure.  A two parameter elastic foundation model is used for contact pressure calculations.  Qualitatively, the results compare favorably to published experimental data collected for copper chemical-mechanical-polishing.  Although entirely mechanical, perhaps such modeling may provide insight to the mechanics of these surface defects and errors encountered during polishing.