Patent ID: 7342666
Filing Date: 2008-03-11
Classification: G01B,G03F

Abstract:
1. A method for measuring a holding distortion arising in a plate-like sample due to a held state thereof when the plate-like sample is held in the held state, the method comprising: performing a first measurement of a front surface shape of the plate-like sample held in the held state to obtain front surface shape data; performing a second measurement of a back surface shape of the plate-like sample held in the held state to obtain back surface shape data; performing a third measurement of at least one of: a front surface shape of the plate-like sample held in such a way that an inverse distortion arises in the plate-like sample, so as to obtain front surface shape data; and a back surface shape of the plate-like sample held in such a way that the inverse distortion arises in the plate-like sample, so as to obtain back surface shape data, wherein a deformation orientation of the inverse distortion is opposite that of the holding distortion, and a deformation amount of the inverse distortion is substantially equal to that of the holding distortion; obtaining first data pertaining to a variation in thickness of the plate-like sample on the basis of front surface shape data obtained through the first measurement and back surface shape data obtained through the second measurement; obtaining second data by superimposing data pertaining to the holding distortion and data pertaining to the inverse distortion on data pertaining to the variation in thickness, on the basis of one of: the front surface shape data obtained through the first measurement and the back surface shape data obtained through the third measurement; and the back surface shape data obtained through the second measurement and the front surface shape data obtained through the third measurement; and determining the holding distortion arising in the plate-like sample due to the held state on the basis of the first data and the second data.