| 摘要 |
<p>PROBLEM TO BE SOLVED: To increase the flatness of absorption substrate for suppressing the image distortion, by a method wherein a device is provided with a substrate supporting protrusions forming a circular protrusion so as to provide a means for diminishing the change in shape of the substrate locally caused near the ammular protrusions. SOLUTION: A wafer 1 is mounted on a mounting surface 2 while a first edge banks 4 as circular protrusion are provided on a mounting surface 2 around through holes 3 penetrating from the mounting surface 2 to the back side thereof. Furthermore, a second edge bank 5 as a protrusive circular rim is provided on the outer periphery of the mounting surface 2. Next, protrusions 6 for supporting the mounted wafer 1 are provided on the mounting surface 2 between the first and the second edge banks 4, 5. Besides, the level of the first edge banks 4 is specified to be slightly lower than that of protrusions 6 scattering around the bank 4 by a specific amount, so that the change in shape of the wafer 1 locally caused near the ammular protrusions 4 when the wafer 1 is absorbed by negative pressure may be effectively diminished.</p> |
