This work describes freeform source optimization considering mask error enhancement factor (MEEF), optical proximity effect (OPE), process window, and hardware-specific constraints. Our algorithm allows users to define maximum allowed MEEF and OPE error as constraints without defining weights among the metrics. We also consider hardware specific constraints, so that the optimized source is suitable to be realized in Nikon’s Intelligent Illumination hardware. Our approach utilizes a global optimization procedure to arrive at a freeform source shape solution, and since each source grid-point is assigned as variable, the source solution encompasses the maximum amount of degrees of freedom.

Date Published: 12 April 2013
PDF: 7 pages
Proc. SPIE 8683, Optical Microlithography XXVI, 86830O (12 April 2013); doi: 10.1117/12.2008267

Published in SPIE Proceedings Vol. 8683:
Optical Microlithography XXVI
Will Conley, Editor(s)