Correlation of errors in optical coating production with broad band monitoring

Abstract

We propose a robust estimate that can be used for the prediction of the expected strength of thickness errors correlation in the case of optical coating production with the direct broad band monitoring of a deposition process. A practical application of this estimate requires statistical analysis. We introduce a computationally efficient simulator of thickness errors that have a random character and are able to adequately represent the correlation of thickness errors by a monitoring procedure. It is shown that the expected strength of thickness errors correlation is estimated by the random value whose distribution is close to the log-normal distribution and that the two main parameters of the log-normal probability density function can be used as the parameters characterizing the investigated effect.