Patent ID: 6940595
Filing Date: 2005-09-06
Classification: G01J

Abstract:
1. A method of monitoring and/or controlling fabrication of filters which reject a central band of wavelengths while passing wavelengths outside thereof, comprising the steps of; in either order practicing steps a and b: a) providing a system for fabricating band-reject filters which comprises means for depositing alternating layers of high and low refractive Index materials onto a substrate; and b) providing a spectroscopic ellipsometer system; c) applying said spectroscopic ellipsometer system to said system for fabricating band-reject filters such that a substrate can be monitored in a transmission mode, by a beam of polarized spectroscopic electromagnetic radiation provided by said spectroscopic ellipsometer system, said spectroscopic ellipsometer system being oriented so as to direct a beam of polarized spectroscopic electromagnetic radiation upon said substrate surface at an oblique angle; d) placing a substrate into said system for fabricating band reject filters; e) while depositing a plurality of alternating high and low refractive Index layers onto said substrate, in real-time determining the ellipsometric PSI and/or DELTA vs. wavelength; f) utilizing the resulting ellipsometric PSI and DELTA vs wavelength data to monitor and/or control the fabrication process.