System zum Steuern der Ausrichtung eines Substrats

摘要

A principal part of an attitude control system comprises: holding means 30 for holding wafers W so that the wafers W are rotatable in circumferential directions; rotation transmitting means 40 for contacting a peripheral portion of each of the wafers W to rotate the wafers W; a stepping motor 50 for rotating the wafers W; transmission switching means 60 for selectively transmitting a power from the stepping motor 50 to the rotation transmitting means 40; a photo sensor 70 for detecting a notch Wa formed in the peripheral portion of each of the wafers W; and a CPU 80 for controlling the operations of the stepping motor 50 and the transmission switching means 60 on the basis of a detection signal outputted from the photo sensor 70. Thus, the notch Wa of each of the rotating wafers W is detected, and the stepping motor 50 and the transmission switching means 60 are controlled on the basis of the detection signal, so that it is possible to carry out the positioning of the wafers W. Thus, it is possible to provide a substrate-attitude control system capable of preventing dust from being produced to reduce the wear of a driving part to enhance the reliability of the system.