Lithographic apparatus and device manufacturing method.

摘要

A lithographic projection apparatus comprises an exposure system (2) and a measurement system (3). The exposure system projects a patterned beam onto a target portion of a first substrate (8), while the measurement system projects a measurement beam on a target portion of a second substrate (13). Movement of a movable part of the apparatus generates a disturbance in a position of another movable part of the apparatus, e.g. due to displacement of air. This error can be compensated by calculating a compensation signal which is a function of states of one or both of the movable parts.