Interferometer, lithography apparatus, and method of manufacturing article

摘要

An interferometer includes: an optical system configured to generate interfering light by dividing light from a light source, and combining reference light and measurement light; a detector configured to detect the interfering light generated by the optical system; and an optical member configured to give spatial coherence to the light from the light source before the detector detects the light from the light source. The optical member gives higher spatial coherence in a second direction serving as a direction of a line of intersection of a cross section of a beam of the light incident on the optical member, and a plane including optical paths of the light from the light source before being divided by the optical system, the reference light, the measurement light, and the interfering light, than in a first direction perpendicular to the plane.

主权项

1. An interferometer comprising:
an optical system configured to generate interfering light by dividing light from a light source, and combining reference light generated by reflecting one beam of the divided light by a reference surface, and measurement light generated by making the other beam of the divided light obliquely incident on an object to be detected and reflecting the other beam by the object; a detector configured to detect the interfering light generated by the optical system; an optical member configured to give spatial coherence to the light from the light source before the detector detects the light from the light source; and a spectral unit configured to disperse the interfering light generated by the optical system, wherein the optical member gives higher spatial coherence in a second direction serving as a direction of a line of intersection of a cross section of a beam of the light incident on the optical member, and a plane including optical paths of the light from the light source before being divided by the optical system, the reference light, the measurement light, and the interfering light, than in a first direction perpendicular to the plane, and wherein the spectral unit makes a direction of wavelength resolution parallel to the second direction.