| 摘要 |
PURPOSE:To enable to detect the position of a wafer with high precision at a high speed by a method wherein the number of light receiving elements for detection of wafer alignment marks is made as to be enabled to be selected arbitrarily corresponding to aiming precision. CONSTITUTION:An operator selects any one of light receiving element selecting (aiming precision change-over) switches 111A-111C corresponding to aiming precision of alignment. At a wafer process disregardful about looseness of precision of alignment, when the switch 111C of 0.5mu of aiming precision is selected out of the switches 111, for example, informations thereof are transmitted to a microprocessor 106 through a decording circuit 112, and the processor 106 outputs an instruction to select light receiving elements of four pieces to a selection signal generating circuit 103. Moreover, at a wafer process to necessitate high alignment precision, by selecting the switch 111A of 0.1mu of aiming precision, the measurement of the position is performed according to the light receiving element of one piece. Accordingly, alignment fitted for the purpose can be performed at a high speed. |
