| 摘要 |
<p>PURPOSE:To provide a wafer floating detector by which floating of a wafer from a wafer disk in a wafer holding mechanism arranged on the wafer disk can be detected. CONSTITUTION:This wafer floating detector has optical heads 20 and 22 arranged in fixed blocks 14 and 16 of respective wafer holding mechanisms 10 of a wafer disk 4. The optical head 20 outputs light 25 from the reverse side of the wafer disk 4 so as to advance toward the optical head 22 close to a surface of the wafer disk 4. The light 25 from a light emitting unit 24 outside of a vacuum vessel 2 is introduced to this optical head 20 through optical fiber 28 and a relay lens unit 34. The light 25 from the optical head 22 is introduced to a light receiving unit 26 outside the vacuum vessel 2 through a relay lens unit 34 and optical fiber 30.</p> |
