A numerical algorithm and simulation results are presented for microscopic profile evolution of material surfaces subject to plasma etching (reactive-ion etching) and surface passivation. Surface evolution is calculated by the shock-tracking method, which accurately simulates formation and evolution of facet corners. The angle distribution for the reemission of sputtered materials is assumed to follow an arbitrary cosine law (i.e., is-proportional-tocos(beta) THETA, with THETA being the reemission angle and beta>0). Thickness of sidewall passivation layers and resulting etched profiles are shown to depend sensitively on both the reemission angular distribution and the sticking coefficient.