| 摘要 |
<p>Mask-to-wafer alignment in X-ray lithography is advantageously carried out utilizing zone plate marks formed on the mask and wafer. In practice, it has been observed that the intensity and in some cases even the location of the centroid of the light spot formed by a zone plate mask can vary during alignment as the mask-to-wafer spacing is changed. In accordance with the invention, the zone plate (18) on the mask (12) is encompassed within an illumination blocking layer (72) for preventing undesired transits and reflections of the illuminating beams.</p> |
