Patent ID: 8319510
Filing Date: 2012-11-27
Classification: G01R

Abstract:
1. A method for conducting a pre-alignment operation of a semiconductor wafer under a control of a control apparatus prior to a processing of the semiconductor wafer, comprising: mounting the semiconductor wafer transferred from a receiving unit by a transfer mechanism on a rotating body of a pre-alignment mechanism; rotating the semiconductor wafer on the rotating body of the pre-alignment mechanism; detecting a shaft center of the rotating body and a center of the semiconductor wafer by a sensor of the pre-alignment mechanism; calculating an eccentric value between the shaft center of the rotating body and the center of the semiconductor wafer based on a detected value at the detecting step; storing the eccentric value between the shaft center of the rotating body and the center of the semiconductor wafer calculated at the calculating step; determining whether the eccentric value calculated at the calculating step exceeds a predetermined value; when it is determined that the eccentric value calculated at the calculating step exceeds the predetermined value, correcting a positional deviation of the semiconductor wafer on the rotating body by the transfer mechanism according to the eccentric value calculated at the calculating step; determining whether the number of the semiconductor wafer transferred to the rotating body is more than a predetermined number; when it is determined that the number of the semiconductor wafer is more than the predetermined number, estimating the eccentric value of a succeeding semiconductor wafer based on the eccentric value stored at the storing step; and mounting the succeeding semiconductor wafer on the rotating body based on the eccentric value estimated at the estimating step.