Method for measuring orthogonality, stage apparatus and exposure apparatus

摘要

A projection exposure apparatus has a function to measure orthogonality between movement mirrors for interferometers for measuring positions of a substrate table in X and Y directions. The substrate table is moved by a distance L along a direction of a third axis which is included in an XY plane and inclined at an angle alpha with respect to a Y axis, while operating a movement mirror and an interferometer for the direction of the third axis. A component in the Y direction corresponding to the distance L in the direction of the third axis is defined as d. A movement distance of the substrate table in the X direction after movement of the substrate table by the distance L in the direction of the third axis is determined by the interferometer for measuring the position in the X direction, which is defined as S. An orthogonality error theta can be determined in accordance with theta =tan-1[(d-S)/d]. The position of the substrate table can be correctly controlled by moving the substrate table while giving an offset to correct the error. This function can be also applied to a mask stage.