28 May 2004 Correction of 157-nm lens based on phase ring aberration extraction method
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Abstract
Early manufacture and use of 157nm high NA lenses has presented significant challenges including: intrinsic birefringence correction, control of optical surface contamination, and the use of relatively unproven materials, coatings, and metrology. Many of these issues were addressed during the manufacture and use of International SEMATECH’s 0.85NA lens. Most significantly, we were the first to employ 157nm phase measurement interferometry (PMI) and birefringence modeling software for lens optimization. These efforts yielded significant wavefront improvement and produced one of the best wavefront-corrected 157nm lenses to date. After applying the best practices to the manufacture of the lens, we still had to overcome the difficulties of integrating the lens into the tool platform at International SEMATECH instead of at the supplier facility. After lens integration, alignment, and field optimization were complete, conventional lithography and phase ring aberration extraction techniques were used to characterize system performance. These techniques suggested a wavefront error of approximately 0.05 waves RMS--much larger than the 0.03 waves RMS predicted by 157nm PMI. In-situ wavefront correction was planned for in the early stages of this project to mitigate risks introduced by the use of development materials and techniques and field integration of the lens. In this publication, we document the development and use of a phase ring aberration extraction method for characterizing imaging performance and a technique for correcting aberrations with the addition of an optical compensation plate. Imaging results before and after the lens correction are presented and differences between actual and predicted results are discussed.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jeff Meute, Jeff Meute, Georgia K. Rich, Georgia K. Rich, Will Conley, Will Conley, Bruce W. Smith, Bruce W. Smith, Lena V. Zavyalova, Lena V. Zavyalova, Julian S. Cashmore, Julian S. Cashmore, Dominic Ashworth, Dominic Ashworth, James E. Webb, James E. Webb, Lisa Rich, Lisa Rich, } "Correction of 157-nm lens based on phase ring aberration extraction method", Proc. SPIE 5377, Optical Microlithography XVII, (28 May 2004); doi: 10.1117/12.544256; https://doi.org/10.1117/12.544256
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