| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface configuration measuring instrument by means of scanning for achieving high resolution without being affected by relative error when acquiring a surface configuration by measuring a difference in height between measurement points. SOLUTION: A double sharing interferometer comprises two heterodyne sharing interferometers. A surface 138 under test (SUT) is illuminated at equally spaced three points on a straight line to measure a difference in height between neighboring two points by a pair of phase meters 132 and 134. As the scanning of a specimen by three beams, closed scanning is performed by a stage 140 wherein phase difference signals are measured for each equal space while data on phase difference are stored and a return is made to the starting point of scanning. Since relative error in height between phase meters can be obtained by using a fact that the starting point and an end point of scanning are on a level, the surface configuration of the specimen can be obtained by calibrating the relative error. COPYRIGHT: (C)2006,JPO&NCIPI
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