| Popis: |
Critical dimensions in current and next generation devices are driving the need for tighter overlay registration tolerances and improved overlay metrology tool accuracy and repeatability. Tool matching, performance evaluation, and a move towards closed-loop image placement control all place an increase on the importance of improved accuracy and calibration methodology. In response to these industry needs, the National Institute of Standards and Technology (NIST) is introducing a calibrated overlay wafer standard. There are, however, a number of calibration requirements, which must be addressed when using these standards. These include identification of the best methods for evaluating uncertainties when using traceable, calibration artifacts, proper data acquisition and analysis, and the best calibration strategy. |
