[en] The present work is dedicated to the application of topology optimization in the coupled simulation of multiphysic field problems as in MEMS. Precisely, it describes how it is possible to maximize pull-in voltage of an electromechanical microsystem for which the optimization domain is insulated from the electric field. The electromechanical coupling is modeled by the use of a monolithic analysis. The monolithic modeling combined with a Riks-Crisfield algorithm allows computing accurately the pull-in conditions. The optimization task is completed with the help of a sequential convex linear approximation schemes (CONLIN).