Patent ID: 8681341
Filing Date: 2014-03-25
Classification: G01B

Abstract:
1. A shape measuring method comprising: a first step of guiding light emitted from a light source having a broadband spectrum to an object to be measured and a reference surface, combining light reflected from the object to be measured with light reflected from the reference surface, and taking a distribution image of an interference light intensity corresponding to each measurement position of a measurement surface of the object to be measured, the interference light intensity changing in accordance with an optical path length difference between a first optical path length from the light source to the object to be measured, and a second optical path length from the light source to the reference plate; a second step of, while changing the optical path length difference between the first optical path length and the second optical path length over a whole scanning zone, sequentially storing distribution images of the interference light intensity of only a plurality of measurement zones which are partly set in the whole scanning zone; and a third step of obtaining an interference light intensity string which indicates a change of the interference light intensity due to a change of the optical path length difference at each measurement position based on the stored distribution images of the interference light intensity of the measurement zones, obtaining a peak position of the interference light intensity string in the whole scanning zone from the interference light intensity string, and obtaining a position in an optical axis direction at each measurement position of the object to be measured from the peak position.