Method and apparatus for controlling thickness of a layer of an optical data storage device by measuring an optical property of the layer

摘要

Disclosed is a method and apparatus for depositing material on a substrate by periodically measuring an optical property of a region thereof, thereby obtaining a substantially continuous profile of the property for that region. The measured value of the property is compared with a predetermined value, and when the two values are substantially equal, deposition is terminated, thereby resulting in correct and reproductible layer thicknesses.