To evaluate the adequacy of a profile model, an initial profile model is selected. The profile model includes profile model parameters to be measured in implementing types of process control to be used in controlling a fabrication process. A measurement of profile model parameters is obtained using a first metrology tool and the profile model. A measurement of the profile model parameters is obtained using a second metrology tool and the profile model. Statistical metric criteria are calculated based on the measurements of the profile model parameters obtained using the first and second metrology tools. When the calculated statistical metric criteria are not within matching requirements, the profile model is revised. When the calculated statistical metric criteria are within matching requirements, the profile model or the revised profile model is stored.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. Ser. No. 11/472,133, titled OPTICAL METROLOGY MODEL OPTIMIZATION FOR PROCESS CONTROL, filed Jun. 20, 2006, issued as U.S. Pat. No. 7,221,989, which is a continuation of U.S. Ser. No. 10/888,726, titled OPTICAL METROLOGY MODEL OPTIMIZATION FOR PROCESS CONTROL, filed Jul. 8, 2004, issued as U.S. Pat. No. 7,065,423, both of which are incorporated herein by reference in their entireties for all purposes.
Optical metrology tools are matched by obtaining a first set of measured diffraction signals, which was measured using a first optical metrology tool, and a second set of measured diffraction signals, which was measured using a second optical metrology tool. A first spectra-shift offset is generated based on the difference between the first set of measured diffraction signals and the second set of measured diffraction signals. A first noise weighting function for the first optical metrology tool is generated based on measured diffraction signals measured using the first optical metrology tool. A first measured diffraction signal measured using the first optical metrology tool is obtained. A first adjusted diffraction signal is generated by adjusting the first measured diffraction signal using the first spectra-shift offset and the first noise weighting function.
Verifying a process margin for a mask pattern includes receiving the mask pattern for patterning features on a semiconductor wafer. The mask pattern is modified according to a wafer pattern model operable to estimate a wafer pattern resulting from the mask pattern. An intermediate stage model is selected to apply to a portion of the mask pattern, where the intermediate stage model is operable to estimate an intermediate stage of the wafer pattern. A process margin of the portion is verified by selecting a test of the intermediate stage model, and performing the test on the portion to verify the process margin of the portion.
