Proposal of a next-generation super resolution technique

A super resolution technique has been developed in order to support next-generation devices. We found that the super resolution technique was effective for smaller patterns but not for larger ones, leading to the restriction of its applicability. In order to obtain wider applicability, we propose a new optical system which has been improved and is applicable to all kinds of mask patterns. According to the proposed optical system, the mask pattern produces a specific source shape preferable for the mask pattern itself. Then the mask pattern is illuminated by this self-optimized illumination source. Thus optimal improvements can be obtained under the same illumination conditions, even if conventional patterns and phase-shift patterns of spatial frequency modulation types and diffracted amplitude modulation types are on the same photomask. Consequently, the super resolution technique will be brought into full use by this optical system.