Method and apparatus for substrate alignment

A semiconductor wafer transport apparatus comprising:

• a frame;
• a transport arm movably mounted to the frame and having at least one end effector movably mounted to the transport arm so that the at least one end effector traverses relative to the frame;
• an optical edge detection sensor, connected to the frame and communicably coupled to a static wafer aligner station on the frame, the optical edge detection sensor configured so as to register and effect edge detection of a wafer supported by the at least one end effector;
• and
• an illumination source connected to the frame configured so as to illuminate a surface of the wafer, supported by the at least one end effector, which surface delineates a peripheral edge of the wafer, the illumination source being disposed with respect to the optical edge detection sensor so that the surface directs reflected surface illumination, from the illumination source, toward the optical edge detection sensor, and optically obscures, at the peripheral edge of the wafer, background reflection light of a background, viewed by the optical edge detection sensor coincident with traverse, to the static wafer aligner station, of the wafer supported by the at least one end effector;
• wherein the peripheral edge of the wafer is defined in relief in image contrast, formed by and between wafer surface reflection and the optically obscured background, registered by the optical edge detection sensor so as to effect edge detection coincident with traverse of the wafer supported by the at least one end effector.