We demonstrate an antireflective coating structure, which is based on the three-layer metal interference called the Fabry-Perot structure, for a deep-ultraviolet binary mask. The antireflective coating structure is composed of a metal-oxide-metal stack. By addition of different optimized structures, reflectances of less than 1.5% at both 248 and 193 nm have been achieved. At the three-layer Fabry-Perot structure, the bottom chrome layer provides suitable absorption. By controlling the thickness of the intermediate silicon oxide layer, we can tune the minimum-reflection regime to the desired exposure wavelength. The top metal layer can prevent charge accumulation during e-beam writing.
© 2002 Optical Society of America
(220.3740) Optical design and fabrication : Lithography
(310.1210) Thin films : Antireflection coatings
(310.1620) Thin films : Interference coatings
(310.1860) Thin films : Deposition and fabrication
Hsuen-Li Chen, Tieh-Chi Chu, Chien-Kui Hsu, Fu-Hsiang Ko, and Tiao-Yuan Huang, "Fabry-Perot-type Antireflective Coating For Deep-Ultraviolet Binary Photomask Applications," Appl. Opt. 41, 3961-3965 (2002)