Wafer positioning device

A positioning device, comprising:

• a charge coupled device camera adapted to detect a first region which is larger than a wafer to be detected by the charge coupled device camera so as to encompass the edge of the wafer to be detected;
• a backlighting source adapted to direct light to a second region which extends outwardly from at least the edge of the wafer to be detected by the charge coupled device camera;
• wherein the charge coupled device camera and the backlighting source are located beyond a first surface of the wafer;
• a controller operatively coupled to the charge coupled device camera adapted to determine the wafer'position based on the backlighting detected by the charge coupled device camera;
• and
• a rough surface located beyond a second surface of the wafer so that light scatters as it reflects therefrom.

A fabrication tool, comprising:

• a first wafer handler chamber containing a first wafer handler adapted to transfer wafers;
• a second wafer handler chamber containing a second wafer handler adapted to transfer wafers;
• a pass-through chamber coupled between the first wafer handler chamber and the second wafer handler chamber, adapted to receive wafers traveling between the first wafer handler chamber and the second wafer handler chamber;
• and
• a positioning device, operatively coupled to the pass-through chamber so as to detect the position of a wafer passing therethrough, the positioning device comprising:
• a charge coupled device camera adapted to detect a first region which is larger than a wafer to be detected by the charge coupled device camera so as to encompass the edge of the wafer to be detected;
• a backlighting source adapted to direct light to a second region which extends outwardly from at least the edge of the wafer to be detected by the charge coupled device camera;
• wherein the charge coupled device camera and the backlighting source are located beyond a first surface of the wafer;
• a controller operatively coupled to the charge coupled device camera adapted to determine the wafer's position based on the backlighting detected by the charge coupled device camera;
• and
• a surface located beyond a second surface of the wafer.