The State of Soft X-ray Projection Lithography in Japan

Soft X-ray projection type Lithography has been expected to be most atractive technology in future electronics device production, paticularly since the realization of normal incidence soft x-ray mirror [1]. For instance, Kinoshita et al [2] and other groups [3,4] have already shown the feasibility of this technology, adopting a Schwartzschild optical system composed of normal mirrors. If neglecting process speed or throughput, it is widely accepted the projection type lithography is the one of most fascinateing candidate for future excess 1 G electronics device fabrication. For realizing this technology as a successor of Excimer and/or proximity x-ray lithography, a long range research and development have already started in Japan, at first individual necessitate component such as conpact SR source, typically SiC substrate mirror and multilayer mirror fabrications, including optical design works [5] for this purpose.