Maskless lithographic fine patterning on deeply etched or slanted surfaces, and grayscale lithography, using newly developed digital mirror device lithography equipment

In the trial and research phases, the fabrication of micro electro mechanical systems (MEMS) devices and integrated circuits (ICs) is both lengthy and costly, owing to the demands imposed by the use of photomasks. Maskless lithography techniques, such as electron beam (EB), laser scanning, and digital mirror device (DMD) lithography techniques, are widely used. In the MEMS field, submicron and wiring patterns are often created on uneven structures. We have developed a maskless lithography technique by modifying a DMD with two automatically switchable lenses. The first lens with a magnification power of 10× and a numerical aperture (NA) of 0.3 was used to rapidly expose wide areas, and the second lens with a magnification power of 100× and an NA of 0.9 was used for fine patterning. In the present study, we fabricated submicron patterns, wiring patterns, and alignment marks on slanted and deeply etched surfaces, and three-dimensional photoresist structures using our developed DMD lithography technique.