Multiple patterning is the only known way to extend current 193 nm immersion-based optical lithography beyond 40 nm half-pitch. A highly effective technique for multiple patterning uses self-aligned etched spacers to define the tightest pitch lines as critical features. However, to complete the patterning, the lines must be cut with at least one separate additional exposure. In order to reduce the costs associated with multiple cut locations, it is proposed to group the locations into portions of larger features. Specifically, the cut locations can be the intersection of the spacer lines and the overlap of at least two polygons of opposite exposure polarity. The cost reduction is determined by the reduced number of exposures, as well as the looser pitch and dimensions of the exposures. Besides cost reduction, greater immunity to exposure shot noise (if EUV or EBL is used for cutting) is provided by the use of larger polygons. The benefits of complementary polarity patterning based on these key issues will be analyzed for the 10 nm half-pitch application, and extensions to even smaller half-pitches will be discussed.

Date Published: 13 March 2012
PDF: 10 pages
Proc. SPIE 8326, Optical Microlithography XXV, 83262L (13 March 2012); doi: 10.1117/12.912800

Published in SPIE Proceedings Vol. 8326:
Optical Microlithography XXV
Will Conley, Editor(s)