Optical monitoring of coating production: correlation of errors and errors self-compensation

It is shown that the previously proposed geometric approach adequately describes the effect of error correlation based on the results of computational manufacturing experiments with the selected type of optical monitoring. The question of a sufficient number of simulation runs is investigated, and it is shown that a reliable estimate of the correlation coefficient describing the strength of the error correlation effect is obtained with a realistic number of computational manufacturing experiments. To investigate the presence of the error self-compensation effect, the error self-compensation coefficient is introduced. Using sets of correlated error vectors obtained in computational manufacturing experiments, the probability density function of the distributions of this coefficient is calculated. To assess the strength of the error self-compensation effect, the estimate is proposed based on a comparison of the influence of correlated and uncorrelated thickness errors.