A technique for conformal processing of a substrate having a non-planar surface is disclosed. The technique includes several stages. In a first stage, some surfaces of the substrate are effectively processed. During a second stage, these surfaces are treated to limit or eliminate further processing of these surfaces. During a third stage, other surfaces of the substrate are processed. In some applications, the surfaces that are perpendicular, or substantially perpendicular to the flow of particles are processed in the first and second stages, while other surfaces are processed in the third stage. In some embodiments, the second stage includes the deposition of a film on the substrate.