System and method for controlling light scattered from a workpiece surface in a surface inspection system
AssigneeKLA-Tencor Technologies Corporation
InventorsRichard Earl Bills, James Peter McNiven
Life of this patent
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Abstract
A surface inspection system, as well as related components and methods, are provided. The surface inspection system includes a beam source subsystem, a beam scanning subsystem, a workpiece movement subsystem, an optical collection and detection subsystem, and a processing subsystem. The system features masking positioned in the collection and detection subsystem arranged to selectively prevent a portion of scattered light from passing through. Also included is a scatter absorbing system having a series of scatter absorbing elements for minimizing unrelated to the scatter associated with a desired location on the surface.
Claims20
An optical collection and detection system for use in a surface inspection system for inspecting a surface of a workpiece, the surface inspection system having an incident beam projected through a back quartersphere and toward a desired location on the surface to impinge thereon to create reflected light and scattered light, the optical collection and detection system comprising:
- a detection subsystem operatively coupled to a collector module, the detection subsystem having a light detection unit arranged to detect the scattered light and generate signals in response;
- a detector relay assembly positioned between the workpiece surface and the light detection unit along a detector optical axis and arranged to permit a first portion of the scattered light to pass therethrough to the light detection unit;
- and
- a mask positioned between the detector relay assembly and the light detection unit along the detector optical axis and arranged to selectively prevent a portion of the first portion of the scattered light from passing through to the light detection unit;
- wherein the detector relay assembly further comprises a cube arranged to permit the first portion of the scattered light to pass therethrough to the light detection unit;
- and the mask is optically bonded to the cube.
An optical collection and detection system, for use in a surface inspection system for inspecting a surface of a workpiece, the surface inspection system having an incident beam projected through a back quartersphere and toward a desired location on the surface to impinge thereon to create reflected light and scattered light, the optical collection and detection system comprising:
- a detection subsystem operatively coupled to a collector module, the detection subsystem having a light detection unit arranged to detect the scattered light and generate siginals in response;
- a detector relay assembly positioned between the workpiece surface and the light detection unit along a detector optical axis and arranged to permit a first portion of the scattered light to pass therethrough to the light detection unit;
- and
- a mask positioned between the detector relay assembly and the light detection unit along the detector optical axis and arranged to selectively prevent a portion of the first portion of the scattered light from passing through to the light detection unit,
- wherein detector relay assembly further comprises a cube arranged to permit the first portion of the scattered light to pass therethrough to the light detection unit and the mask is optically bonded to the cube;
- and the mask is switchable in the collection and detection system by moving the cube into another location.
Dependencies are inferred from the claim text.