Inverse Lithography Technology (ILT) is gaining acceptance as part of a comprehensive OPC solution especially as a repair technique to locally improve process window where conventional OPC does not have enough degrees of freedom to produce acceptable results. [1] Since ILT is significantly more computationally intensive than conventional OPC, a localized application of ILT does not significantly increase OPC cycle time. As ILT methods mature and become more efficient, combined with the availability of huge compute clusters for post tape out data processing, the possibility of full-field ILT OPC could soon become reality. Full-field ILT OPC may provide improved process window and greater layout flexibility as long as multi-patterning methods with 193 nm exposure wavelength remain the primary lithography strategy for advanced technology nodes. Due to limitations of photomask lithography tools that prevent efficient exposure of non-Manhattan shapes, ILT OPC output is typically post-processed to conform to mask MRC rules, rendering the raw all-angle features to a Manhattanized equivalent. Previous comparisons of raw vs Manhattan ILT OPC at earlier nodes have shown that a Manhattanized output can be made to print on wafer with equivalent process window while conforming to mask manufacturing rules.[2,3,4] In this paper we use wafer-level lithography simulation to compare raw vs Manhattanized ILT output based on current advanced nodes and MRC rules. We expand this study to include a mask model to ensure that mask corner rounding effects are considered.

Date Published: 3 October 2016
PDF: 8 pages
Proc. SPIE 9985, Photomask Technology 2016, 99850V (3 October 2016); doi: 10.1117/12.2243030

Published in SPIE Proceedings Vol. 9985:
Photomask Technology 2016
Bryan S. Kasprowicz; Peter D. Buck, Editor(s)