Position sensor system for substrate holders

摘要

The position sensor (20) and method of the present invention allows detecting proper placement of substrate holders (25) in a processing apparatus (35), and can also be used to detect displacement of the substrates (70) within the substrate holder (25). The position sensor (20) comprises (a) an optical emitter (120) capable of emitting a light beam, (b) an optical sensor (125) capable of sensing the light beam emitted by the optical emitter (120), and (c) a light regulator (130) in a path (135) of the light beam that is capable of blocking the light beam from the optical sensor when the substrate holder (25) is improperly positioned in the process chamber (40).