Patent ID: 6950181
Filing Date: 2005-09-27
Classification: H01L

Abstract:
1. A wafer presence optical sensor system comprising: a transfer chamber adapted to receive a wafer, said transfer chamber comprising a chamber lid and a chamber bottom having an inner surface, said chamber lid being provided with a transparent window; an optical sensor comprising means for emitting a sensing beam and means for receiving a beam reflected from said wafer to ascertain wafer presence in said chamber, said sensor being adjusted relative to said chamber lid so as to let said sensing beam and said reflected beam pass through said window; and means for reflecting said sensing beam away from said means for receiving a beam when said sensing beam reaches said chamber bottom, said means for reflecting said sensing beam having a surface oblique relative to the sensing beam, said surface forming coincident to an area of the inner surface of the chamber bottom and forming a non-planar surface therewith, whereby receipt by said receiving means of said beam reflected from said non-planar surface of said reflecting means of chamber bottom is prevented, and thus misinterpretation of wafer presence is thwarted.