Photolithographic element blank calcium strontium fluoride UV transmitting mixed fluoride crystal with minimized spatial dispersion

摘要

The invention provides a UV below 200 nm lithography method utilizing mixed calcium strontium fluoride crystals. The invention includes providing a below 200 nm radiation source for producing 200-nm light, providing a plurality of mixed calcium strontium cubic fluoride crystal optical elements, with the fluoride crystals comprised of a combination of calcium strontium cations having different optical polarizabilities such as to produce an overall isotropic polarizability which minimizes the fluoride crystal spatial dispersion below 200 nm, transmitting 200-nm light through the cubic fluoride crystal optical elements, forming a lithography pattern with the light, reducing the lithography pattern and projecting the lithography pattern with the fluoride crystal optical elements onto a UV radiation sensitive lithography printing medium to form a printed lithographic pattern. The invention includes making the mixed fluoride crystals, optical element blanks thereof and optical lithography elements.