Multiple-exposure interferometric lithography

摘要: Interference effects between two coherent laser beams have long been used to create simple grating patterns in photoresist. With the addition of multiple exposures with variations period, phase, and orientation, same level photoresist, highly complex one‐ two‐dimensional potential interest for device application are demonstrated. The spatial scale lines forming these is ∼1/4 writing wavelength λ (period λ/2 line space ratio 1:1) extreme submicron range, ∼0.1 μm, readily available sources, such as an Ar+‐ion operating at 364 nm. Importantly, depth‐of‐focus pairwise unlimited on typical semiconductor topographies large area, uniform scales much larger than projected integrated circuit die sizes (e.g., 30×30 cm2) easily achieved. These closely related moire interference patterns; relationships illustrated. Diffractive readout shown be a powerful intuitive technique monitoring structures. Additional flexibility pattern fabrication provided conventional lithography define areas by use aperture phase masks isolate areas. An example interdigitated structure spaces over area.