X-ray mask making by EBL and Monte Carlo analysis of a single-resist layer process on low-Z membrane

X-ray masks are fabricated utilizing a single-resist layer process and boron nitride (BN) substrate. Final absorber structures are obtained by Au electroplating after e-beam patterning at 20 and 30 keV electron energy. Great improvement is observed, going from 20 to 30 keV, and high resolution structures were written down to 0.2 µm. The results are analyzed in terms of Monte Carlo simulation and the proximity function. At 20 keV, a remarkable contribution to back-scattering is found from the 200 Å Au plating base, which drops dramatically at 30 keV.