Optical device and inspection method
AssigneeNikon Corporation
InventorsNaonori Kita, Masanori Arai
Life of this patent
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Abstract
An optical device for inspecting a to-be-inspected surface having a riblet structure in which projections each extending in a first direction are provided in a second direction intersecting the first direction is configured to include a condensing optical system that irradiates an irradiation region on the to-be-inspected surface with light from a light source and that condenses light reflected by the irradiation region; and a photodetector that has a photosensitive surface disposed on a plane different from a plane conjugate to the to-be-inspected surface with respect to the condensing optical system, and that detects intensity distribution of the light condensed by the condensing optical system.
Claims28
An optical device for inspecting a to-be-inspected surface having a riblet structure in which projections each extending in a first direction are provided in a second direction intersecting the first direction, the optical device comprising:
- a condensing optical system;
- a photodetector that has a photosensitive surface disposed on a plane different from a plane conjugate to the to-be-inspected surface with respect to the condensing optical system;
- and
- a processor, wherein
- light from a light source irradiates an irradiation region on the to-be-inspected surface through the condensing optical system,
- light irradiating the irradiation region on the to-be-inspected surface and reflected by the irradiation region is condensed by the condensing optical system and detected by the photodetector, and
- the processor is configured to determine an appropriateness of a shape of the projections, based on intensities of (i) first reflected light reflected once by a region where the projections are not provided in the irradiation region and detected by the photodetector, and (ii) second reflected light reflected twice by the projections and the region where the projections are not provided in the irradiation region and detected by the photodetector.
An inspection method for inspecting a to-be-inspected surface having a riblet structure in which projections each extending in a first direction are provided in a second direction intersecting the first direction, the inspection method comprising:
- irradiating an irradiation region on the to-be-inspected surface with light;
- condensing, with a condensing optical system, light reflected by the irradiation region in response to irradiation with the light;
- receiving the condensed light by a photodetector disposed on a plane different from a plane conjugate to the to-be-inspected surface with respect to the condensing optical system;
- and
- inspecting the riblet structure by determining an appropriateness of a shape of the protections, based on intensities of (i) first reflected light reflected once by a region where the projections are not provided in the irradiation region and detected by the photodetector, and (ii) second reflected light reflected twice by the projections and the region where the projections are not provided in the irradiation region and detected by the photodetector.
Dependencies are inferred from the claim text.