Patent ID: 7922882

Claim:
A substrate holding device comprising: a holder on which a substrate is to be loaded; a plurality of engagement elements arranged to lie aside of the periphery of the substrate when the substrate is placed at a specified position on the holder, the plurality of engagement elements being each provided to be engageable to a peripheral region of the substrate to hold the substrate on the holder; an opening/closing mechanism for opening the plurality of engagement elements from their closed positions in which the engagement elements engage the peripheral region of the substrate placed at the specified position on the holder to their open positions in which the engagement elements retract outwardly away from the peripheral region of the substrate and closing the plurality of engagement elements from the open positions to the closed positions; a plurality of detectors for detecting different associated parts of the peripheral region of the substrate placed at the specified position on the holder; and a determination unit for determining that the substrate is placed offset from the specified position on the holder when at least one of the plurality of detectors did not detect the associated part of the peripheral region of the substrate.