| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique advantageous to measurement of distance between a reference surface and a surface to be detected.SOLUTION: A measurement method for measuring distance between a reference surface and a surface to be detected includes, for each light of two wavelengths different from each other, a first step for detecting an interference signal corresponding to interference light of light reflected on the reference surface and light reflected on the surface to be detected and acquiring length of an optical path between the reference surface and the surface to be detected from the interference signal, a second step for, on the basis of difference in the length of an optical path between the two wavelengths acquired in the first step, acquiring difference in a periodic error included in each of the length of an optical path of the two wavelengths acquired in the first step, and a third step for acquiring the length on the basis of the length of an optical path of the two wavelengths acquired in the first step and difference in the periodic error acquired in the second step.SELECTED DRAWING: Figure 1 |
