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2000
Conference Paper
Titel
DUV/VUV light scattering measurement of optical components for lithography applications
Abstract
This paper reports on an instrument designed to measure the total backward and forward scattering of optical components down to the DUV/VUV spectral region. The system is based on a Coblentz sphere imaging the light scattered into the backward or forward hemispheres within an angular range from 2° to 85° onto the detector according to ISO/DIS 13696. The equipment divides into two set-ups, one operating in air at several wavelengths from 10.6 mum to 193 nm, the other one working in vacuum/ nitrogen at 157 nm and 193 nm. The system is fully automated and capable of scanning large sample areas. Both a deuterium lamp and an excimer laser can be used as radiation sources at 193 nm and 157 nm. Results of measurements on fluoride multilayer coatings and CaF2 substrates are presented.