Group iia metal fluoride single crystals suitable for below 200 nm optical lithography and a method for selecting such crystals

摘要

The invention is directed to a method for determining metal fluoride crystals that are suitable for use in below 200 nm optical lithography by correlation of thermally stimulated current (TSC) measurements to fluence dependent transmission (FDT) measurements; and to metal fluoride crystals suitable for below 200 nm optical lithography, such crystals having a fluent dependent transmission slope that is linearly dependent on the thermally stimulated peak maximum. Crystals suitable for below 200 nm lithography can be determined by using the standard linear relationship between the TSC peak strengths and the FDT slopes without further more FDT measurements.