| 摘要 |
PROBLEM TO BE SOLVED: To calculate the deviating of a transparent or silicon dummy wafer by providing a wafer carrying accuracy detecting means for a wafer carrying chamber. SOLUTION: A wafer carrying accuracy detecting means 7 is constituted of a light source 8 which projects light upon a transparent dummy wafer 4 and a transparent blade 5 before and after the blade 5 is moved, an image receiving section 9 composed of a camera, etc., which takes the pictures of the wafer 4 and blade 5, an output section 10 composed of a monitor, etc., which displays the pictures taken by means of the section 9 and has ruled lines 22, and an arithmetic section 12 which calculates the deviation of the wafer 4 from the blade 5 based on a coincident point and provided for a wafer carrying chamber 2. Since the scale of the blade 5 is marked as the vernier of the ruled lines of the wafer 4, the carrying accuracy of the wafer 4 can be improved by detecting the positional deviation of the wafer 4 on the blade by utilizing the vernier. |
