Soft X-Ray Lithography for High-Aspect Ratio Sub-Micrometer Structures

J. Goettert, S. Lemke, I. Rudolph, T. Seliger, B. Loechel
Louisiana State University, US

Keywords: soft X-ray lithography, high aspect ratio micro and nanostructures, optical gratings, fluid filters

Summary:

Combining soft x-ray lithography with SiN mask membrane and newly developed high contrast negative resist mr-X (micro resist technology GmbH, Berlin, Germany) enables the cost-effective patterning of sub-micrometer high aspect ratio structures. This work builds upon a new negative-tone, epoxy-based x-ray resist which offers comparable contrast to PMMA > 3) at a factor of 20x higher sensitivity. Using a 1µm thick SiN membrane mask with a ~1µm thick Au absorber, patterns were transferred into 10µm thick resist using the soft exposure mode at the BESSY WLS beamline. With typical exposure of a few minutes very precise grating and filter structures can be fabricated with dimensions down to about 500nm.