Parallel Process Focus Compensation

Disclosed are systems, methods, and computer program products for parallel process focus compensation. Such methods may include three steps. First, a first sensor senses a top surface of a wafer to provide first-sensor data which defines a first topographic map of the first surface of the wafer. The first sensor may be, for example, an air gauge. Second, a second sensor senses the top surface of the wafer in parallel with the first sensor to provide second-sensor data which defines a second topographic map of the first surface of the wafer. The second sensor may be, for example, an optical sensor or a capacitance sensor. Third, a calibration module calibrates focus-positioning parameters of an exposure system based on the first- and second-sensor data. The calibration module may be embodied in hardware, software, firmware, or a combination thereof.