Projection electron lithography using aperture lenses

Methods are presented for using two-dimensional (axially symmetric) aperture lenses of both the single- and multiaperture (fly´s-eye) kind and one-dimensional (planar-symmetric) aperture lenses in image-projection systems for electron lithography. The basic electron-optical properties of such aperture lenses are derived. The ancillary film technology is discussed, including pre-exposure and postexposure resist processes in use and the techniques developed for fabricating electron-transmission object masks that can withstand the requisite electron bombardment during image projection. The image-projection systems developed for use in fabricating arrays of thin-film field emitters, electron-beam-addressed memory planes, optical waveguides, and interdigital transducers (unapodized and apodized) for surface-acoustic-wave devices are described, and representative examples of each device produced are shown.