Fig. 1. Schematic diagram of level sensor

Fig. 2. Schematic diagram of measurement spots

Fig. 3. Sampling and fitting areas of height map and wafer map. (a) Height sampling areas; (b) fitting areas of wafer map

Fig. 4. Schematic diagram of focus error

Fig. 5. Experimental platform of lithography and focus control. (a) Level sensor and base frame; (b) wafer stage and interferometer

Fig. 6. Height map measured by level sensor. (a) Full wafer; (b) center Die

Fig. 7. Wafer map of static exposure. (a) Full wafer; (b) center Die

Fig. 8. Wafer stage motion trajectories of static exposure. (a) Z-axis; (b) Rx-axis; (c) Ry-axis; (d) center Die

Fig. 9. Reconstruction results of parametric wafer map. (a) Full wafer; (b) center Die

Fig. 10. Wafer stage motion trajectories based on parametric surface. (a) Z-axis; (b) Rx-axis; (c) Ry-axis; (d) center Die

Fig. 11. Evaluation results of full wafer focus error. (a) MAFE_die; (b) MSDFE_die