摘要 |
<p>POSITIONING SYSTEM A method of, and apparatus for, positioning semiconductor wafers for precision operations is provided. As a first step, a distinctive portion of a first wafer is chosen. The distinctiveness of the portion is verified by comparing, the distinctive portion to portions intermediate to the distinctive portion and disposed around the distinctive portion. The distinctive portion is then compared with progressive portions on the wafer along a particular axis to determine rotary deviations of the wafer from disposition along the particular axis. Corrections are then made in the rotary disposition of the wafer in accordance with such comparisons. The displacement of such distinctive portion from a starting position on the wafer is then determined.</p> |