Patent ID: 9062967
Filing Date: 2015-06-23
Classification: G01B

Abstract:
1. A measurement apparatus for measuring a measurement surface based on an interference signal obtained from measurement light reflected by the measurement surface and reference light reflected by a reference surface interfering with each other, the measurement apparatus comprising: a first interference optical system including a lens configured to focus the measurement light to be incident on the measurement surface, and cause the measurement light and the reference light to interfere with each other; an adjusting device configured to adjust a focusing state of the measurement light focused by the lens so that a measurement point on the measurement surface positions within a range of a depth of focus of the lens; and a second interference optical system configured to measure a position of the first interference optical system in a direction along an optical axis of the lens, with the focusing state adjusted by the adjusting device, wherein the measurement surface is measured based on the measured position and the interference signal, and wherein the interference signal is obtained with the focusing state adjusted by the adjusting device.