| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an apparatus and a method for detecting a positional deviation of a wafer capable of surely detecting the positional deviation of the wafer even when the deviation occurs in any direction with respect to a normal position and detecting by using a small number of optical sensors. SOLUTION: A wafer processing unit comprises first and second optical sensors 13 and 14 having invariable positions with respect to a base. The first and second sensors are disposed in a positional relationship in which, when an arm mechanism is in a most contracted state, the first sensor becomes a shielding state of the wafer 17 and the second sensor becomes a light receiving state while, when the mechanism is a state except the most contracted state, the first sensor becomes the light receiving state and the second sensor becomes the shielding state. The wafer is decided to be a normal state when the first sensor is the receiving state and the second sensor is the shielding state at a first wafer detection time and the wafer is decided so that the positional deviation occurs when the first and second sensors are in states except the above states.</p> |
