We developed a fast simulator for the chemical mechanical polishing (CMP) process that works in nonperiodic boundary conditions. Since periodic boundary conditions are not used, it can calculate anywhere on a wafer, such as the wafer's edge. Additionally, we enhanced the simulator to calculate the shallow trench isolation (STI)-CMP process. In the STI-CMP simulation method, additionally required simulation parameters are only one, under the assumption that dishing reaches steady state in enough short time relative to total polishing time. We found that the simulation results could match experimental film thicknesses with an error range of about 10-20 nm and that the calculation time was reduced to 1/20 relative to when the acceleration method was not introduced. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3519133] All rights reserved.