Title of article :
Effect of surface quality on transmission performance for (111) CaF2
Author/Authors :
Rebecca S Retherford، نويسنده , , Robert Sabia، نويسنده , , Vincent P Sokira، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2001
Pages :
6
From page :
264
To page :
269
Abstract :
With the advent of 193 nm optical lithography, calcium fluoride (CaF2) has become the material of choice for excimer laser components and for chromatic aberration correction of stepper lens systems. Paralleling the need to maximize transmission performance is the challenge of processing CaF2 to surface qualities equal to if not superior than for conventional fused silica optics. In this report, (111) calcium fluoride crystals were processed to two different surface qualities and tested for transmittance from 185 to 400 nm. Results show that surface quality in terms of mid- and high-spatial frequency roughness and subsurface damage strongly affect transmittance with a greater increase in transmittance with improved surface quality at lower wavelengths. Specifically for 193 nm, transmittance increased from 90.30% for a 1.4 nm RMS surface to 91.98% for a 0.8 nm RMS surface (Δ=1.68%).
Keywords :
CaF2 , Polishing , Surface roughness , Subsurface damage , Transmittance
Journal title :
Applied Surface Science
Serial Year :
2001
Journal title :
Applied Surface Science
Record number :
997414
Link To Document :
بازگشت