Technique for Projection X-Ray Lithography Using Computer-Generated Holograms,
Abstract:
A method is described whereby projected lithographic images can be formed with x-rays by means of a transmission hologram. The form of the hologram is computed by an algorithm which eliminates all the unwanted signals normally present as systematic errors in holographic images. An example calculation is shown in which the form of a hologram is derived that is supposed to generate a diffraction image of a given test pattern. The holographic image is shown to have excellent fidelity with respect to both resolution and contrast. Such an approach to projection x-ray lithography requires an x-ray beam with very little coherence and is thus compatible with high wafer throughput schemes while at the same time being relatively immune to contamination.