Polarimetric diagnosis of 193-nm lithography equipment using a mask with newly developed polarization optical elements

Two lithographic test masks, Stokes polarimeter mask and Mueller matrix polarimeter mask, are introduced. Both the masks comprise newly developed thin polarizers and wide-view-angle λ/4 plates. Photomasks are only 6.35 mm in thickness, and the illumination involves the oblique incidence of 20° at the most. Calcite plates thinned to less than 0.1 mm can perform as polarizers only at a wavelength of 193 nm. The combination of quartz and sapphire plates can mitigate the retardation change with angle of incidence. Stokes polarimeter and Mueller matrix polarimeter masks are used for the measurement of the illumination and the projecting optics, respectively.