Inspection system with fiber coupled OCT focusing
AssigneeKLA-Tencor Corporation
InventorAmnon Manassen
Life of this patent
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Abstract
An optical inspection system can include an optical coherent tomography (OCT) tool having an optical column with a beam splitter optically coupled to an objective. Illumination optics are coupled to the beam splitter. An OCT focusing system is optically coupled to the objective via the beam splitter. The OCT focusing system includes a broadband light source, a reflector, a photo-detector, all of which are connected by optical fiber to a fiber coupler in an interferometer configuration. The objective is optically coupled to the fiber coupler in the OCT focusing system by an optical fiber.
Claims16
An inspection system, comprising:
- an optical metrology tool having an optical column with a beam splitter optically coupled to an objective;
- illumination optics coupled to the beam splitter;
- an optical coherence tomography (OCT) focusing system having a broadband light source, a shiftable reflector, a photo-detector, all of which are connected by optical fiber to a fiber coupler in an interferometer configuration that is remote from the optical column, the OCT focusing system further including a fiber collimator optically coupled to the fiber coupler by an optical fiber, wherein the objective is optically coupled to the fiber coupler in the OCT focusing system by an optical fiber;
- and
- an illumination beam splitter optically coupled between the illumination optics and the beam splitter in the optical column, wherein the beam splitter is optically coupled to the fiber collimator,
- wherein the broadband light source is optically coupled to the illumination optics by a separate optical path that does not include the fiber coupler.
An inspection system, comprising:
- an optical metrology tool having an optical column with a beam splitter optically coupled to an objective, wherein the objective includes a reflective objective;
- illumination optics coupled to the beam splitter;
- an optical coherence tomography (OCT) focusing system having a broadband light source, a shiftable reflector, a photo-detector, all of which are connected by optical fiber to a fiber coupler in an interferometer configuration that is remote from the optical column;
- a dedicated optical fiber that passes through an opening in a central obscuration of the reflective objective, wherein a first end of the dedicated fiber is optically coupled to the fiber coupler and wherein a second end of the dedicated fiber is located along an optical axis of the objective between the central obscuration and a focal point of the objective,
- wherein the objective is optically coupled to the fiber coupler in the OCT focusing system by an optical fiber.
Dependencies are inferred from the claim text.