EUV lithography is expected to be introduced in volume manufacturing at the 10-nm and 7-nm node. Especially in these first EUV nodes, critical layer patterning will be balanced with the use of ArF immersion. As a consequence a good overlay and placement matching between both lithography methods becomes an enabling factor for EUV. In this paper we present an integral method to optimize critical layer patterning across the EUV and ArF scanner platform, such that good overlay and device pattern placement is achieved. It is discussed that besides classical overlay control methods, also the optimization of the ArF and EUV imaging steps is needed. Best matching is achieved by applying high-order field-to-field overlay corrections for both imaging and overlay. The lithography architecture we build for these higher order corrections connects the dynamic scanner actuators with the angle resolved scatterometer via a separate computational application server. Improvements of CD uniformity are based on source mask optimization for EUV combined with CD optimization using freeform intra-field dose actuator in the immersion scanner.

Date Published: 17 April 2014
PDF: 9 pages
Proc. SPIE 9048, Extreme Ultraviolet (EUV) Lithography V, 90481L (17 April 2014); doi: 10.1117/12.2048314

Published in SPIE Proceedings Vol. 9048:
Extreme Ultraviolet (EUV) Lithography V
Obert R. Wood II; Eric M. Panning, Editor(s)