Patent ID: 7670729

Claim:
A measurement method for measuring a distortion of a projection optical system that projects a reticle pattern, which can include a plurality of first marks and a plurality of second marks, wherein the projection optical system is usable by an exposure apparatus that exposes the reticle pattern onto an object, said measurement method comprising: a first exposing step of exposing the plurality of first marks onto the object, the plurality of first marks being arranged on or near an optical axis of the projection optical system and beside the optical axis; a second exposing step of exposing at least one of the plurality of second marks onto the object on or near the optical axis of the projection optical system; a measuring step of measuring a line width of a mark formed on the object via the first exposing step and the second exposing step with an ellipsometer; and a calculating step of calculating the distortion of the projection optical system from the line width of the mark measured in the measuring step, wherein at least one of the first marks has two first repeating patterns, each of which includes third marks as shading parts that are repeatedly arranged, the two first repeating patterns being arrayed in a direction orthogonal to a direction along which the third marks are repeating, and wherein the at least one second mark has two second repeating patterns, each of which includes fourth marks as penetrating parts that are repeatedly arranged, the two second repeating patterns being arranged so that the two first repeating patterns exposed in the first exposing step are shifted in a direction opposite to each other in a direction along which the fourth marks are repeating.