System and method for controlling light scattered from a workpiece surface in a surface inspection system
AssigneeKLA-Tencor Technologies Corporation
InventorsRichard Bills, James 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.
Claims18
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.
A surface inspection system for inspecting a surface of a workpiece, the surface inspection system comprising:
- an illumination subsystem that projects an optical beam to the desired location on the surface of the workpiece, and
- a collection and detection subsystem for collecting reflected light and scattered light formed by the impinging of the optical beam on the surface at the desired location, the collection and detection subsystem further comprising a scatter absorbing system having a series of scatter absorbing elements for minimizing unrelated to the scatter associated with the desired location on the surface.
A surface inspection system for inspecting a surface of a workpiece, the surface inspection system comprising:
- an illumination subsystem that projects a beam to the surface of the workpiece to create scattered light from the surface of the workpiece;
- a collection subsystem for collecting the scattered light, the collection subsystem comprising a plurality of collection lenses, each of the collection lenses having a known surface roughness, the plurality of lenses having a total surface roughness that does not exceed a selected amount of roughness.
Dependencies are inferred from the claim text.