As microelectronic devices continue to shrink and process requirements become ever more stringent, plasma modeling and simulation becomes increasingly more attractive as a tool for design, control, and optimization of plasma reactors. A brief introduction and overview of the plasma reactor modeling and simulation problem is presented in this paper. The problem is broken down into smaller pieces (reactor, sheath. microfeature. and crystal lattice) to address the disparity in length scales. A modular approach also helps to resolve the issue of disparity in time scales.