Determining instantaneous removal rates in metal chemical mechanical planarization

We define a new scientific method, based on experimental and simulation data, for accurately determining instantaneous removal rates (i-RRs) during tungsten and copper chemical mechanical planarization. We show that i-RR changes tremendously depending on how different factors that account for RR are affected by key process parameters that change due to depth-dependent non-uniformities in film morphology, density and elemental composition. After experimentally determining how pad temperature, coefficient of friction (COF), sliding velocity and polishing pressure affect overall RRs, we use a modified Langmuir-Hinshelwood model and show that i-RR for tungsten is governed by COF and not by temperature, while i-RR for copper is a strong function of temperature, and to a lesser extent, a function of COF. (C) 2020 The Japan Society of Applied Physics