| 摘要 |
<p>PURPOSE:To decide the specifications of X rays for exposure and an image forming system so that a high-contrast signal can be obtained from a wafer mark for positioning by detecting secondary electrons generated when the wafer mark is irradiated with the X rays. CONSTITUTION:Soft X rays 1 form an image on the mark of a wafer 7 through two concave mirrors 2 and 4, one convex mirror 5, and one plane mirror 6 after the X rays 1 are reflected by the positions mark pattern of an X-ray mask 2. In this case, the X-ray mask 2 is aligned with the wafer 7 by detecting secondary electron signals from the wafer mark by finely moving a wafer stage 11 and controlling the position of the stage 11 so that the detected signal can become the minimum. Therefore, aligning accuracy of the mask 2 with the wafer 7 can be improved, because the mask 2 can be aligned with the wafer 7 by utilizing an exposure optical system and, at the same time, a high-intensity and high contrast signal can be obtained from the wafer mark.</p> |
