| 摘要 |
The angular position of a notch ( 17 ) is determined on the basis of data provided by second notch detectors ( 24 a) and ( 24 b) and an encoder ( 25 ). A controller ( 38 ) turns a rotational arm ( 22 ) for angular displacement such that holders ( 26 ) and ( 27 ) are displaced in a circumferential direction B from the notch ( 17 ), and then the holders ( 26 ) and ( 27 ) hold a wafer ( 19 ). Since the holders ( 26 ) and ( 27 ) are in touch with edges in which the notch ( 17 ) is not formed, the first notch detector ( 23 ) is able to detect the notch ( 17 ) without difficulty. Thus the position of the wafer ( 19 ) relative to the rotational arm ( 22 ) does not need to be changed several times depending on positions at which the holders ( 26 ) and ( 27 ) hold the wafer ( 19 ), which is necessary in the prior technology. The aligner ( 20 ) touches parts, not including the notch ( 17 ), of the wafer ( 19 ) and is capable of adjusting the position of the wafer ( 19 ) in a short time.
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