Proceedings PaperNew g-Line Lens For Next Generation
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In order to meet the production requirement for higher integration, g-line lenses of higher NA have been developed. It is generally believed that to enlarge both NA and image field is difficult. The maximum image field achieved with a high NA lens has so far been 15 mm square and the maximum NA of a wide image field lens has been 0.35. Canon has recently developed a new g-line lens of higher NA and larger image field. Results of evaluations so far show that the newly developed lens is the best-suited of any yet made for mass-production of 4M DRAMs. This is the 5x reduction lens with a numerical aperture of 0.45 and a field size of 20 mm square (28.2 mm dia.). In this paper, the performance of this lens is discussed, and SEM resist profiles produced by the new lens are shown. The last section gives an overview of progress in development of projection lenses in terms of the amount of information available, and also discusses the possibility of a lens for 16M DRAMs being developed.