EUV lithography for resolution below 9 nm requires the numerical aperture of the projection optics to be significantly larger than 0.45. A configuration of 4x magnification, full field size and 6’’ reticle is not feasible anymore. The increased chief ray angle and higher NA at reticle lead to non-acceptable shadowing effects, which can only be controlled by increasing the magnification, hence reducing the system productivity. We demonstrate that the best compromise in imaging, productivity and field split is a so-called anamorphic magnification and a half field of 26 x 16.5 mm². We discuss the optical solutions for anamorphic high-NA lithography.

Date Published: 16 March 2015
PDF: 10 pages
Proc. SPIE 9422, Extreme Ultraviolet (EUV) Lithography VI, 94221G (16 March 2015); doi: 10.1117/12.2175488

Published in SPIE Proceedings Vol. 9422:
Extreme Ultraviolet (EUV) Lithography VI
Obert R. Wood II; Eric M. Panning, Editor(s)