| Popis: |
Mask Process Compensation (MPC) corrects proximity effects arising from e-beam lithography and plasma etch processes that are used in the photomask manufacturing. Accurate compensation of the mask process requires accurate, predictive models of the manufacturing processes. Accuracy of the model in turn requires accurate calibration of the model. We present a calibration method that uses either SEM images of 2-dimensional patterns, or a combination of SEM images and 1D CD-SEM measurements. We describe how SEM images are processed to extract the contours, and how metrology and process variability and SEM alignment errors are handled. Extracted develop inspection (DI) and final inspection (FI) contours are used to calibrate e-beam and etch models. Advantages of the integrated 2D+1D model calibration are discussed in the context of contact and metal layers. |
