Attenuated phase-shifting mask blanks for the deep ultraviolet

ULCOAT has developed an attenuated phase shifting mask blank which has entered the production level for i-line blanks, with 180 degree(s) shifting angle and 5% to 20% transmittance. A single layer of MoSiON is employed as the phase shifter. Its simple structure enables good repeatability and stability in the mask making process. This single layer has 5% to 8% transmittance, with 180 degree(s) shifting angle at the deep ultra violet level (KrF Laser). However, it cannot be inspected at 488 nm (the wavelength of a popular pattern checker), due to more than 40% transmittance at that wavelength. Therefore, for deep ultra violet level work, a multi-layer type of MoSiON has been developed by ULCOAT, which achieves less than 40% transmittance at 488 nm.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.