Soft X Ray Lithography for High Aspect Ratio Sub Micrometer Structures

Abstract

Soft x ray lithography is a promising micro nano fabrication process for patterning of ultra precise, low and high aspect ratio micro and nanostructures [1 5]. Research presented in this paper builds upon a new negative tone, epoxy based x ray resist, mr X, which offers comparable contrast to PMMA gt; 3 at a factor of 20x higher sensitivity [6]. Using a 1 amp; 956;m thick SiN membrane mask with a 1 amp; 956;m thick Au absorber, patterns were transferred into 10 amp; 956;m thick resist using the soft exposure mode at the BESSY II WLS beamline. With typical exposure times of a few minutes very precise grating and filter structures can be fabricated with dimensions down to about 500nm