Patent ID: 7952725
Filing Date: 2011-05-31
Classification: G01B,G01J,G03B,G03F

Abstract:
1. A surface shape measurement apparatus configured to measure a surface shape of an object to be measured, the surface shape measurement apparatus comprising: a light source configured to emit white light; a beam splitter configured to split the white light from the light source into two light beams; a first prism configured to increase an incident angle of one light beam that has been split by the beam splitter and directed to the object to be measured, the first prism having a first antireflection part that is formed at a period of a wavelength of the white light or smaller and has a moth-eye shape; a second prism configured to increase an incident angle of the other light beam that has been split by the beam splitter and directed to a reference surface of a reference optical element, the second prism having a second antireflection part that is formed at a period of a wavelength of the white light or smaller and has a moth-eye shape; a superimposition unit configured to superimpose object light as reflected light that contains information of a surface shape of the object and has passed the first prism with reference light as reflected light that contains information of a surface shape of a reference surface and has passed the second prism, and to generate white interference light; a Lyot filter configured to discretely separate the white interference light for each of a plurality of wavelengths; a photoelectric conversion element configured to photoelectrically convert the white interference light separated by the Lyot filter; and an operating unit configured to calculate a distribution of a power spectrum based on an output of the photoelectric conversion element, and to calculate the surface shape of the object to be measured by using information on a peak position of the power spectrum.