Patent ID: 6499367
Filing Date: 2002-12-31
Classification: H01L,Y10S

Abstract:
A substrate detecting device for detecting presence and off-position of a circular substrate mounted on a substrate mounting part in a load-locking chamber capable of forming a vacuum, the substrate detecting device comprising:two substrate sensing parts each of which is arranged in a position inwardly departing from an outer peripheral edge of the substrate arranged in a designated position on the substrate mounting part, by a predetermined distance and which are arranged away from each other in the circumferential direction of the substrate; a judgment controlling unit for judging the presence of the substrate on the substrate mounting part and the existence of the substrate's off-position being deviated from the designated position, on the basis of respective outputs from the two substrate sensing parts; and a pair of opposing substrate restricting walls which are arranged on both sides of the substrate mounting part for restricting the mounting position of the substrate to the inside of the substrate restricting walls; wherein the predetermined distance is equal to a maximum amount of the off-position allowed for the substrate; wherein the judgment controlling unit judges: the presence of the substrate on condition that at least one of the two substrate sensing parts detects the presence of the substrate; and the existence of the off-position on condition that one of the two substrate sensing parts detects the presence of the substrate and the other substrate sensing parts does not detect the substrate; and wherein the two substrate sensing parts are arranged in a direction substantially perpendicular to the opposing direction of the substrate restricting walls in pairs.