CHROMIUM FLUORIDE ATTENUATED PHASE-SHIFTING MASK FOR ARGON FLUORIDE EXCIMER-LASER LITHOGRAPHY

Chromium fluoride (CrF) film was chosen as the phase shifter for atten uated phase-shifting masks because of its high transmittance at 193 nm . The refractive index n and absorption coefficient k was derived by u sing the reflectance-transmittance (RT) method. Using argon fluoride ( ArF) excimer laser exposure equipment and a chemically amplified posit ive resist, fine hole patterns were resolved. Depth of focus (DOFs) wi th 0.24 mu m were extended to 30%. The resolution limit was 0.20 mu m, while it was 0.22 mu m with a conventional mask.