| 摘要 |
The present invention relates to position detection, and aligning structure utilizing optical heterodyne method in semiconductor ultra fine processing or ultra accurate measuring. This is to provide a structure which contains pitches of not less than two kinds with respect to grating pitches of diffraction gratings which directly give influences to signal detecting range and detecting resolution, or which contains different values of not less than two kinds with respect to absolute values n of an order of +/-n-th order injecting directions (or +/-n-th order diffraction directions) to be determined by said grating pitches, so as to enable to enlarge a detecting range as maintaining a required detecting resolution (or a structure which can take out diffracted lights in different diffraction directions of not less than two).
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