Scatterometry based measurements of a rotating substrate

摘要

A system and method are disclosed for monitoring characteristics of a rotating substrate. As the substrate rotates in an environment, an incident light beam is emitted onto the substrate near an axis about which the substrate rotates. The emission of the incident beam is controlled as a function of the angular orientation of the substrate, so that the incident beam selectively interrogates a central region of the substrate to facilitate measuring and/or inspecting characteristics of the substrate.