| 摘要 |
<p>An optical mask for high resolution optical lithography using short wavelength light, e.g., 157 nm, uses membranes of a material that is transparent to the desired wavelength. The thin membranes are held under tensile stress by a supporting structure, such as a silicon wafer. Because the membranes are thin, the heating of the membrane material during generation of the overlying lithographic patterns is reduced. This is particularly advantageous when a material such as calcium fluoride is used as the transparent medium of the mask because calcium fluoride has a high thermal expansion coefficient. Thus, the membrane will suffer little distortion during the production of the mask. The lithographic pattern is produced using a thin layer of an absorptive material, such as palladium. Because both the absorptive material and the membrane are thin, there is little back scattering during the generation of the lithographic pattern by e-beam writing, and consequently, no proximity correction is necessary.</p> |
