| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a wafer notch position detector which is capable of accurately detecting the position of a notch at all times, without causing any damage to the surface of a wafer and being affected by disturbance light or the like. SOLUTION: A wafer W is held by the edge with a holding means 1, whereby the holding means 1 is restrained from coming into contact with the surface of the wafer W, so that the surface of the wafer W can be protected against damage. The image of a part or all of the surface of the wafer W is picked up by an image sensing means 4 which is installed confronting the wafer W, and the position of a notch is detected by a notch position detecting means 5 based on the above image. Furthermore, it is preferable that an optical means generates a brightness difference between the wafer and its background on a picked-up picture image. For instance, if the surface of a wafer is a mirror surface, a lighting means is installed at a position so as not to irradiate the image sensing means 4 direct with a reflected light from the surface of the wafer W, and a light scattering member 2 is provided to the background of the wafer W, the edge profile of the wafer W as a boundary between the wafer and the background is clearly reproduced, so that the position of a notch can be accurately detected, and a wafer notch position detector can be lessened in size because a rotating mechanism can be dispensed with.</p> |
