HEIGHT MEASURING INSTRUMENT, AND METHOD OF MEASURING HEIGHT USING THE SAME

摘要

A height measuring instrument comprises an object lens (8) for focusing light from a light source (3) on a sample (9), a moving mechanism (14) for relatively moving the focusing position of the object lens (9) and the position of the sample (9) along the direction of the optical axis of the focused light, a small-aperture member (11) positioned conjugate to the focusing position of the object lens (9), and an optical detector (12) for detecting the intensity of the light passing through the small-aperture member (11). A method of measuring the height of the sample (9) using this height measuring instrument comprises the steps of making two cofocal images by changing the relative position between the focusing position of the object lens (8) and the sample (9), calculating the difference/sum of the outputs from the optical detector (12) for the corresponding individual pixels, and multiplying this calculated value by a predetermined coefficient, thereby obtaining information about the height of each sample point.