Status and future of x-ray lithography

X-ray lithography is relatively mature, and may be used to manufacture complex integrated circuits at 130 nm ground rules and smaller. Overlay and critical dimension control for 180 nm ground rules have been demonstrated with synchrotron-based x-ray lithography. Significant engineering challenges remain in making x-ray masks for 180 nm and smaller ground rules. Extendibility of x-ray lithography to 100 nm ground rules and below will require less than or equal to 20 mu m gaps and careful mask bias optimization.