Method for three-dimensionally measuring a 3d aerial image of a lithography mask

In a method for three-dimensionally measuring a 3D aerial image in the region around an image plane during the imaging of a lithography mask (5) arranged in an object plane (4), a selectable imaging scale ratio in mutually perpendicular directions (x, y) is taken into account. For this purpose, an electromagnetic wavefront of imaging light (1) is reconstructed after the interaction thereof with the lithography mask (5). An influencing variable corresponding to the imaging scale ratio is included. Finally, the 3D aerial image measured with the inclusion of the influencing variable is output. This results in a measuring method which can also be used to measure lithography masks which are optimized for use with an anamorphic projection optical unit during projection exposure. 种用于在光刻掩模(5)成像期间三维测量在像平面周围区域中的3D空间像的方法，光刻掩模布置在物平面(4)中，考虑在彼此垂直方向(x，y)中的可选成像比例比。为此，在成像光与光刻掩模(5)相互作用之后重构成像光(1)的电磁波前。包含对应于成像比例比的作用变量。最后，输出通过包含该作用变量测量的3D空间像。这导致测量方法还可用于测量优化用于在投射曝光期间在变形投射光学单元的情况下使用的光刻掩模。