Patent ID: 6475682
Filing Date: 2002-11-05
Classification: C03C,G03F

Abstract:
A below three-hundred nanometer wavelength ultraviolet lithography light polarization mode dispersion inhibiting photolithography mask blank for producing lithography patterns while inhibiting polarization mode dispersion of transmitted ultraviolet lithography light, said polarization mode dispersion inhibiting mask blank comprised of a fused silica SiO2 glass wafer having a longest dimension length L, a thickness T, a mask blank x-axis, a mask blank y-axis, a mask blank z-axis, said length L lying in a plane defined by said mask blank x-axis and said mask blank y-axis, said thickness T normal to said plane defined by said mask blank x-axis and said mask blank y-axis, said thickness T parallel with said mask blank z-axis, said mask blank having a first refractive index nx in the direction along said mask blank x-axis and a second refractive index ny in the direction along said mask blank y-axis wherein |nxâˆ’ny|&lE;1 ppm.