Simulation of the Substrate Temperature Field for Plasma Assisted Chemical Etching

Surface figuring using reactive plasma jet machining is a promising technology for the manufacture of optical elements. Due to the pure chemical etching mechanism the material removal rate during plasma jet treatment strongly depends on the workpiece surface temperature, which is influenced by the jet heat flux. This paper presents the basis for an enhanced process simulation by introducing a transient heat transfer model including a moving heat source. A comprehensive method of determination for corresponding model parameters has been developed. It is based on temperature measurements during a well defined etching experiment. The model is able to predict the workpiece surface temperature distribution at any given time.