A metrology system

Abstract

A metrology system comprises: a substrate support; a sensor support; a plurality of position sensors; and a processor. The plurality of position sensors are supported by the sensor support and each one is operable to: project a radiation beam onto a substrate; receive a portion of the radiation beam scattered from a target on the substrate; and generate a measurement signal that is indicative of a position of the target relative to that position sensor. The processor is configured to: receive the measurement signal from each of the plurality of position sensors; and to combine the measurement signals from at least two different of the plurality of position sensors to at least partially correct at least one of the measurement signals for a position error so as to determine a corrected position of the target relative to the substrate support.

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