Patent ID: 8044668

Claim:
A method for calibrating a plurality of metrology tools for a semiconductor fabrication process, the method comprising: obtaining a first plurality of calibration standard wafers, the first plurality of calibration standard wafers being associated with a plurality of predetermined values; measuring the first plurality of calibration standard wafers by a plurality of metrology tools to obtain a first plurality of measured values; processing information associated with the first plurality of measured values; selecting a first metrology tool from the plurality of metrology tools based on at least information associated with the first plurality of measured values; calibrating the first metrology tool with the first plurality of calibration standard wafers; obtaining a plurality of working standard wafers; measuring the plurality of working standard wafers by the selected first metrology tool to obtain a second plurality of measured values; associating each of the second plurality of measured values with a corresponding one of the plurality of working standard wafers; and calibrating a second metrology tool of the plurality of metrology tools with the plurality of working standard wafers associated with the second plurality of measured values.