| 摘要 |
<p>This invention relates to apparatus for effecting alignment and spacing control of a mask and wafer for use, for example, in x-ray lithography, which includes, in combination, two optical channels for effecting lateral and vertical alignment at two spaced alignment targets respectively on the element, two spaced position sensors located on a line which is oblique with respect to a line joining the two alignment targets, and linkage for maintaining the distances between the position sensors and the element equal one to the other.</p> |
