Submicrometer lithography using lensless high-efficiency holographic systems

A hologram recording geometry that was total internal reflection of the reference and reconstruction beams from a photosensitive material surface is used to achieve 0.5-microm resolution at lambda = 457 nm in the readout of a reconstructed image on a photoresist. Such a geometry has demonstrated stable image quality for parallel displacement within the illuminated area and diffraction efficiency tolerance within a +/-2 degrees tilt about the axis of the reconstruction beam. The total-internal-reflection recording system provides double-fringe sets for each plane component inside the volume hologram; therefore, a diffraction efficiency as high as 80% was observed. The result is applicable to highvolume submicrometer lithography and can be expanded to a 20-cm (8-in.) semiconductor submicrometer pattern. The use of a large-aperture, well-collimated laser beam provides us with much higher throughput than that of existing lithography machines.