Photoblanks for advanced lithography based on Corning high-purity fused silica (HPFS)

Photomask specifications for advanced KrF and ArF lithography tools require improvements in both glass substrate quality and coating development. CD control and uniformity will be driven by transmission, index and birefringence uniformity of the substrate. Coating development will facilitate the use of advanced resolution enhancement techniques. Progress in the development of Corning's HPFS blanks for advanced lithography applications is reviewed. A variety of new masking materials are being developed to complement HPFS including specialized absorber coatings with low reflectivity and phase shift coatings to enable attenuated phase-shift photomasks. The optical properties of these materials will be described.