157 nm and 193 nm scatter, R and T measurement technique

We report on an arrangement that measures angle resolved scattering (ARS), total scatter (TS), transmittance, (T) and reflectance (R) at 157 nm and 193 rim. The ARS set-up is based on a high precision double goniometer arrangement, which can be inserted into the measurement chamber without removing the TS set-up. The TS set-up for detection of forward scatter and backscatter with extremely low background scatter levels of 1 ppm consists of an excimer laser, a Coblentz sphere with detection system, and a beam preparation path. The sphere and preparation path are housed in vacuum chambers allowing operation in vacuum or purge gas. The measurement options altogether constitute a multifunctional system: VULSTAR (VUV Light Scatter, Transmittance, and Reflectance). We present total scatter measurements on deep ultraviolet (DUV) and vacuum ultraviolet (VUV) substrates and optical components with antireflective (AR) and highly reflective (HR) coatings, angle resolved measurements on optical components and R and T measurements on substrates for VUV optical coatings.