The practical limit of NA using water as immersion liquid has been reached. As a consequence, the k1 in production for the coming technology nodes will decrease rapidly, even below k1=0.25.This means that new imaging solutions are required. Double patterning and spacer techniques in combination with design for manufacturing are developed to support the 22nm node. However, from an imaging point of view the main challenge is to extend and improve single exposures at k1 of 0.26 to 0.31. In this paper we will present ingredients to support single exposure (as a part of a double patterning solution). The following ingredients to extend single exposure are presented in this paper: 1) Extreme Dipole illumination (pole width = 20° and ring width = 0.08σ) to demonstrate tight CD control of 1.5nm across the wafer for a flash gate layer with a half pitch of 38nm. 2) The benefits of complex freeform illumination pupils for process window, pattern fidelity and MEEF using a DRAM active area pattern, and 3) the advantage of TE polarization for rotated structures while maintaining intensity in preferred polarization state.

Date Published: 16 March 2009
PDF: 12 pages
Proc. SPIE 7274, Optical Microlithography XXII, 72741Q (16 March 2009); doi: 10.1117/12.814155

Published in SPIE Proceedings Vol. 7274:
Optical Microlithography XXII
Harry J. Levinson; Mircea V. Dusa, Editor(s)