| Popis: |
Optical Proximity Correction (OPC) modeling has evolved throughout the years to address 2D edge placement corrections, driven mainly out of CDSEM measurement results. 3D pattern modeling, and 3D-OPC for resist pattern, is much more complex. 3D information can be obtained by Optical CD tools for large repetitive arrays, where the outcome is an averaged 3D profile, or by Atomic Force Microscopy (AFM), offering accurate local in-die 3D metrology but can be limited by tip size and can also involve long scan times. In recent years we have presented a 3DSEM imaging methodology using multiple detectors to reconstruct surface morphology. To address the 3D-OPC model characterization challenge we combine in this work two metrology methods; AFM as a reference tool, and 3DSEM. Both metrology techniques provide nondestructive, large statistical sample measurements, across the wafer for lithography process window characterization, and 3D-OPC model calibration. Parameterized test patterns were generated on mask by Synopsys and printed on wafers at IMEC. Selective patterns were measured by 3DSEM and AFM to optimize 3DSEM measurements. Statistically significant 3DSEM measurement results were used for 3D-OPC model calibration, offering 3D-OPC corrections including resist shrink induced by SEM imaging. |
