Patterning Accuracy and Overlay Performance in Step and Repeat X-Ray Lithography

X-ray lithography is now accepted as a promising tool for mass production of 0.5 μm VLSIs. High resolution capability and good process applicability have been confirmed through successful fabrication of MOS devices having the minimum gate length of 0.3 μm. Evaluation of x-ray irradiation damage 2) and mask accuracy have also been performed. This paper evaluates pattern size controllability and registration accuracy, two important subjects in x-ray lithography.