Transfer detection method and substrate processing apparatus

Abstract

Provided is a transfer detection method for use in a substrate processing apparatus including a transfer arm, which has a plurality of substrate holders and is configured to transfer a plurality of substrates to a plurality of stages between a first chamber and a second chamber adjacent to the first chamber by using the plurality of substrate holders, and an optical sensor provided in a vicinity of an opening via which the first and second chambers are in communication with each other, the method including: projecting a light beam having a horizontal optical axis parallel to the opening to a position through which the substrates held by the plurality of substrate holders pass; and determining at least one of a state of the substrates on the substrate holders and a state of the transfer arm, in response to a detection result of the light beam projected from the optical sensor.

Dependencies are inferred from the claim text.