Patent ID: 6726767
Filing Date: 2004-04-27
Classification: C23C,C30B

Abstract:
A method of layer processing comprising using processing apparatus to apply material to a surface to etch it or produce growth upon it, monitoring the surface with a sensor providing an output indicating progress in processing the surface, and using the sensor output in generating a control input for controlling the surface's processing conditions, wherein the control input is generated in accordance with a Bayesian algorithm incorporating the following steps:a) prediction of a distribution of possible parameter values characterising change to the surface, the prediction being on the basis of processing conditions prearranged to produce the change and surface state prior to the change, b) weighting the distribution selectively in accordance with likelihood of the sensor output corresponding to surface states indicated by respective parameter values, c) using the weighted distribution to provide an updated estimate of surface state, d) iterating steps (a) to (c) until processing of the surface is complete.