| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide method and device for measuring the focus characteristic of a projection optical system that can perform high-precision function approximation of a tendency that the length of a projection image of a wedge-shaped projection image varies according to a focus position, and measure the focus characteristic of a projection optical system with high precision.SOLUTION: A wedge-shaped pattern is projected by a projection optical system to form a projection image of the wedge-shaped pattern, and the length in a long-axis direction of the wedge of the projection image or a transfer image of the projection image is measured at each of focus positions Zn of n which are changed in the focal depth direction of the projection optical system by every predetermined amount. When the length in the wedge long-axis direction measured at each of the focus positions Zn of n is represented by Lpn, the length Lpn is defined as a model function f(Zn) containing a trigonometric function having the focus position Zn as a variable. Plural coefficients of the model function f(Zn) are approximately calculated, and a variation characteristic represented by the model function f(Zn) is determined, whereby the best focus position is specified with high precision.</p> |
