Nodal line-scanning method for maskless optical lithography

Maskless optical lithography can improve the economics and performance of multi-patterning by eliminating photomasks and by simplifying the lithography exposure technology. It could also potentially eliminate the need for multi-patterning by enabling dual-wavelength, nonlinear optical recording methods. High-resolution, maskless patterning can be achieved with a scanned-spot-array system in which modulated, diffraction-limited focus spots write the exposure pattern. Each spot has a central zero-intensity interference null along a line parallel to the scan direction for printing sub-resolution line patterns. High throughput can be achieved at the comparatively low repetition rate of excimer lasers (e.g., 6 kHz). The low repetition rate simplifies the optical modulation technology, enabling the use of supplemental modulation controls including dynamic gray-level and beam-centration controls for resolution enhancement. (C) 2014 Optical Society of America