| 摘要 |
<p>PURPOSE:To prevent a substrate from damage or wound by holding contact or a collision to the peripheral part of the substrate to be nil by a method wherein the quantity of discrepancy of the peripheral part of the substrate during conveyance is detected according to two non-contact sensors, and proper alignment of the substrate is effected automatically. CONSTITUTION:When a conveyance chuck 18 attracts and fixes a substrate 2, and transfers to the direction of a referential point 0 whereto the substrate is to be aligned, sensors 19, 19' are shaded with the peripheral part A-D of the substrate. Outputs of the sensors generated at this time are inputted to a controller 21, the positions in the orthogonal directions corresponding to outputs thereof are sought after respectively, and the coordinate positions (a, b) of the central position Oomega and the radius Romega of the substrate are sought from the coordinate positions of four points. Alignment is performed by seeking the coordinate positions of the peripheral parts of the substrate in the midway of conveyance of the substrate like this, contact of a positioning fork, etc., is not performed, and alignment is performed in perfect no-contact condition.</p> |
