摘要 |
An attenuated phase-shifting photomask (APSM) provides adjustment of attenuation from mask to mask. The APSM includes a multilayer substrate, a buffer thin film coupled to the substrate, and a top layer thin film on top of the buffer thin film. The thin films are etched with a circuit pattern to form a photomask, and are chosen to have certain thicknesses which would provide adjustment of attenuation within a specified attenuation operating range and appropriate phase shift without changing said buffer thin film and said top layer thin film.
|