Abstract

In a previous paper dealing with a high-rate automated deposition system (ADS),¹ it has been shown that it is possible to fabricate complex coatings accurately if the gas process control is optimized. For this ADS system, the thickness control depends upon fitting the measured transmittance of a layer to determine its thickness. However, depending on the type of filter to be fabricated, different thickness determination strategies may have to be employed in order to ensure that all the layers in the filter are deposited accurately. In addition, the thickness determination strategy for a given filter must be robust to ensure that the same filter performance can be achieved from run-to-run. In this paper, we will discuss the systematic errors that may occur with this thickness determination method and describe different thickness determination strategies for various filters including broad-band antireflectance coatings, edge filters, bandpass filters and partial reflectors. The run-to-run repeatability for this ADS system is demonstrated by depositing a set of five different filters five times in a row.

© 1998 Optical Society of America