| 摘要 |
To calibrate a registration measurement system for use in semiconductor fabrication processes, a calibration structure is provided. The calibration structure includes at least one zero offset registration structure and a plurality of non-zero offset registration structures. By measuring the displacement of the zero registration structure at 0.degree. and 180.degree., the tool induced shift of the registration measurement system may be determined. Then, by measuring the displacement of the zero offset registration structure at 0.degree., 90.degree., 180.degree., and 270.degree. the initial TIS determination is verified and the presence or absence of astigmatism is established. When TIS and astigmatism have been accounted for, all of the registration structures, both zero and non-zero, are measured at an angular orientation of 0.degree. to determine the systematic errors present in the measurement. Once these errors are determined, the registration measurement system is calibrated to alleviate these errors.
|
