| 摘要 |
<p>PURPOSE:To easily and accurately perform binarization processing by providing a wafer set part to the head part of a wafer installation base and making the size of the wafer set part smaller than the external diameter of a wafer to be recognized. CONSTITUTION:The wafer set part which has a surface smaller than the external diameter of the wafer 1 to be set is formed at the head part of the wafer installation base 2. The edge part of the external diameter of the wafer 1 is not mounted directly in contact with the set part 6. Consequently, none of the reflected light of irradiating light from illuminator 4 and 5 is made incident on the edge part of the wafer 1 from the set part 6. An image of the edge part is therefore a high-contrast, sharp image and the binarization processing of the output of a CCD camera 3 which picks up the high-contrast, sharp image has no room for an error. The wafer 1 is therefore accurately recognized.</p> |
