The photomask technologies in hyper-NA lithography

This is a report of the panel discussion in PMJ 2005 on April 16, 2005. We discussed in the session on the technologies of photomask for hyper-NA lithography, with six invited panellists of two from LSI manufacturers, a lithography researcher, one from a lithography tool supplier, one from an EDA vendor and one from a photomask supplier. First, we had short presentations by the panellists on the issues brought about by hyper-NA lithography from their own technological points of view, and we knew their extensive efforts to overcome the difficulties in hyper-NA lithography. By the presentations, we had been impressed that ArF immersion technique was almost one and only promising candidate of the lithography methods which we could employ in the technology nodes of 65nm and beyond, and, that the technologies for hyper-NA lithography were then already within our hands. We discussed the difficulties inherent to hyper-NA lithography and recognized the needs of further engineering efforts to obtain maximal performance in the lithography. There were some who expressed the necessity of the change of photomask magnification because of the compatibly small features on a photomask to using wavelength in the lithography. The attendants could confirm the positions of their opinions by the insitu statistic results of the questionnaire we had had in the conference.