In this paper, the progression of optical lithography from a spectral (or wavelength) perspective is presented. The
interdependencies between materials, sources, design challenges, and scaling are described relative the needs of
semiconductor device generations. Comparisons of materials and approaches for use in the blue-UV, the mid-UV, the
deep-UV, and to EUV wavelengths are provided showing the spectral influences for choices made. Inorganic and
organic lithography materials, sources of radiation, and incremental wavelength "shrink" are compared for lithography
generations from g-line to EUV and beyond.