| 摘要 |
PROBLEM TO BE SOLVED: To perform highly accurately three-dimensional measurement of the diffraction grating shape of an optical element. SOLUTION: A probe 11 is allowed to abut on a diffraction optical element W<SB>1</SB>held by a jig 2, and while the probe 11 is allowed to scan along a scanning route T<SB>1</SB>-T<SB>8</SB>on the XY-plane by an XY-stage comprising an X-slider 13 and a Y-slider 16, Z-position data of the probe 11 by a Z-interferometer 23 are taken, to thereby acquire three-dimensional shape data. The scanning route T<SB>1</SB>-T<SB>8</SB>determined to be in parallel with a ring belt (vertex) of each grating by using a phase function which is design shape information of the diffraction grating is stored in a control device 30, and the XY-stage is controlled so that the probe 11 scans by avoiding the vertexes of the diffraction grating as much as possible, to thereby prevent a measurement error or deterioration of measurement accuracy. COPYRIGHT: (C)2005,JPO&NCIPI
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