Abstract: The present invention provides a method for calculating a corrected substrate height map of a first substrate using a height level sensor. The method comprises: sampling the first substrate by means of the height level sensor with the first substrate moving with a first velocity, wherein the first velocity is a first at least partially non-constant velocity of the first substrate with respect to the height level sensor, to generate a first height level data, generating a first height map based on the first height level data, and calculating a corrected substrate height map by subtracting a correction map from the first height map, wherein the correction map is calculated from the difference between a first velocity height map and a second velocity height map.

Abstract: A lithographic apparatus is disclosed. The lithographic apparatus comprises a substrate table configured to support a substrate; actuators configurable to move the substrate table in a plane substantially parallel to the surface of the substrate; a projection system configured to pattern the substrate with fields aligned in a scanning exposure direction; a level sensor configured to sense a height of the substrate using a plurality of measurement spots; and a controller configured to control the actuators to generate strokes of relative movement between the substrate and the level sensor for mapping the height of the substrate, said strokes being at an angle of less than 20 degrees relative to the scanning exposure direction. Also disclosed is an associated method of mapping the height of a substrate.

Abstract: The present invention provides a method for calculating a corrected substrate height map of a first substrate using a height level sensor. The method comprises: sampling the first substrate by means of the height level sensor with the first substrate moving with a first velocity, wherein the first velocity is a first at least partially non-constant velocity of the first substrate with respect to the height level sensor, to generate a first height level data, generating a first height map based on the first height level data, and calculating a corrected substrate height map by subtracting a correction map from the first height map, wherein the correction map is calculated from the difference between a first velocity height map and a second velocity height map.