The morphological change of silver nano-particles (AgNPs) exposed to an intense synchrotron X-ray beam was investigated for the purpose of direct nano-scale patterning of metal thin films. AgNPs irradiated by hard X-rays in oxygen ambient were oxidized and migrated out of the illuminated region. The observed X-ray induced oxidation was utilized to fabricate nano-scale metal line patterns using sectioned WSi2/Si multilayers as masks. Lines with a width as small as 21 nm were successfully fabricated on Ag films on silicon nitride. Au/Ag nano-lines were also fabricated using the proposed method.
Keywords: Fresnel zone plate; X-ray lithography; hard X-ray focusing.