Recent work with dielectric resonant reflector underlayers has shown improvements in high aspect ratio imaging via solid immersion evanescent interference lithography in the ultra-high numerical aperture (UHNA) regime. Controlling the gap at the prism/sample interface has proven to be a problem for good reproducibility, uniformity and quality of UHNA regime, high aspect ratio, resist structures. Here we present simulated and experimental results for fine tuning of the prism/sample interface to achieve greater uniformity of high aspect ratio resist structures over large exposure fields in the evanescent regime. These results highlight our solid immersion Lloyd’s mirror interference lithography (SILMIL) system’s limitations in the absence and presence of an index-matching layer (IML) through the use of gap control measurements and attenuated total internal reflection (ATR) measurements with various index mismatched prism/IML pairs. Finally, we present simulated results for a system that will produce uniform, high aspect ratio resist structures over large exposure fields.

Date Published: 19 March 2015
PDF: 17 pages
Proc. SPIE 9423, Alternative Lithographic Technologies VII, 94231W (19 March 2015); doi: 10.1117/12.2175627

Published in SPIE Proceedings Vol. 9423:
Alternative Lithographic Technologies VII
Douglas J. Resnick; Christopher Bencher, Editor(s)