| 摘要 |
PROBLEM TO BE SOLVED: To provide a slit-projection-type sample height detection device in which the detection accuracy hardly decreases even when the diffraction angle of primary diffraction light occurring on a sample surface increases.SOLUTION: When the illumination light having passed through a slit opening part OP1, namely an image of the slit opening part OP1, is reduced and projected on a sample S by an objective lens 17, the planar shape of the slit opening part OP1 is set to a shape defined by one rectangle or a shape defined by overlaying a plurality of rectangles on each other on a plane. The length of the short side of the rectangle is set at Mλ/(2 NA) or shorter. Here, M [times] shows the reduction magnification of the image of the slit opening part OP1 by an illumination optical system 10, NA shows the numerical aperture of the objective lens 17, and λ [nm] shows the wavelength of the illumination light coming into the illumination optical system 10.SELECTED DRAWING: Figure 1 |
