193 nm fluoride antireflection coatings

The effect of different substrates and different fluorides are studied to develop low loss, high-performance 193 nm fluoride antireflection coatings. Different fluoride antireflection coatings are deposited by a molybdenum boat evaporation process on JGS1 substrates, and the thickness of the coatings is controlled by a 1/3 baffle with pre-coating technology. Experimental results and analyses show that all of these coatings have a low residual reflectivity and small optical loss, and the optical loss at 193 nm is mainly determined by the high refractive index film. Based on these studies, an LaF3/AlF3 193 nm antireflection coating is designed and deposited. Its residual reflectivity is less than 0.14%, single-sided transmittance is 93.85%, total loss is about 6% and RMS surface roughness is