| 摘要 |
PURPOSE:To make it possible to measure the depth and width of an individual trench structure of LSI at high speed and with high precision, by a method wherein a coherent beam for measurement is restricted by a lens having large NA and a stage retaining the lens is moved with high resolution in the direction of height. CONSTITUTION:A beam L emitted from a light source 1 is restricted to be 1mum or below by a lens 3 so that the waist of the beam L is adjusted on the surface 4a of a semiconductor substrate 4, and it is projected to a point A on said surface. A reflected light thereof is made to fall onto a point A' on a detecting surface of an optical image position detector 5. A height detector 6 determines the height (displacement) as a reference value from an output of the detector 5 and sets same in a reference value setting unit 11. The lens 3 is fixed to a moving stage 7 provided with a driving device 8, so that the lens can be moved in the direction of height with a resolution of 0.1mum or above, and the amount of movement is determined by a position detector 12. When the beam L is made to fall into a trench with the substrate 4 moved subsequently, it is reflected at a point B on a bottom surface 4b and falls onto a point B' on the detecting surface of the detector 5. Thereby, an output of the detector 5 is varied, and the height detected by the detector 5 is also varied.
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