Patent ID: 7440116
Filing Date: 2008-10-21
Classification: G01B

Abstract:
1. Surface profiling apparatus for obtaining surface topography data for a surface of a sample, the apparatus comprising: a sample support to support the sample; a light director operable to direct light along a sample path towards the sample surface and along a reference path towards a reference surface such that light reflected by corresponding regions of the sample surface and the reference surface interfere; a mover operable to effect relative movement along a measurement path between the sample surface and the reference surface; a sensor operable to sense, for each of a number of regions of the sample surface, light representing the interference fringes produced by that sample surface region during said relative movement; a controller operable to carry out a measurement operation by causing said mover to effect said relative movement while said sensor senses light intensity at intervals to provide, for each of the number of regions, a set of intensity values representing interference fringes produced by that region during said relative movement; a data processor operable to process the sets of light intensity data to determine from the light intensity data values associated with each sensed region a position along the measurement path at which a predetermined feature occurs in the light intensity data for that sensed region; and a surface topography determiner operable to determine from the positions at which the predetermined feature occurs in the light intensity data for the different sensed regions the relative surface heights of the different sensed regions to provide surface topography data, the apparatus further comprising: a reference calibrator operable to calibrate the apparatus to compensate for surface features of the reference surface, the reference calibrator comprising: