Patent ID: 6721626
Filing Date: 2004-04-13
Classification: H01L,Y10S

Abstract:
A wafer transfer system having a transfer unit wherein arms for transferring wafers are provided on a turntable, an orientation unit which adjusts the orientation and direction of the wafer set on a place table and a reading unit which reads an ID mark put in the wafer, comprising:a calculation means which calculates a central position of the wafer set on the place table; a turn angle calculation means for calculating a turn angle of the place table for the wafer to be in a predetermined orientation based on a calculation result of the calculation means and positional information of the ID mark received in advance; a transfer quantity calculation means which calculates a quantity of expanding and contracting the arm in the transfer unit and a turn angle of the turntable necessary for setting the wafer in the predetermined orientation such that the ID mark comes to a predetermined position and orientation to the reading unit; and, a correction means which corrects the turn angle of the place table calculated by the turn angle calculation means based on the turn angle of the turn table calculated by the transfer quantity calculation means.