Extreme ultraviolet scatterometer: design and capability

摘要

A scatterometer capable of plane-of-incidence bidirectional reflectance distribution function (BRDF) measurements at extreme ultraviolet wavelengths between 58.4 and 121.6 nm has been developed. This instrument has a lower measurement limit of approximately 10↑(-5 )sr↑(-1), and it is able to accommodate angles of incidence between 10° and 75°. The scatterometer can measure scatter to within 1.5° of the specular beam, and the scatter angle can be measured to within 0.1°. The design, analysis, and performance of this instrument are discussed here. Scatter data, in the form of BRDF measurements, are presented for a 3000-line/mm grating and a fiat chemical vapor deposited diamond sample.# 1997 Optical Society of America