Kla Tencor Corporation

Ade Optical Systems Corporation

Songping Gao

Richard Earl Bills

Neil Judell

Ian T Kohl

Chris Koliopoulos

Michael Murphree

Bruce W Baran

John C Stover

Michael E Fossey

Lee Dante Clementi

An optical collection and detection system for use in a surface inspection system for inspecting a surface of a workpiece. The surface inspection system has an incident beam projected through a back quartersphere and toward a desired location on the surface, which is a scanned spot having a known scanned spot size. The incident beam impinges on the surface to create scattered light that is collected by a collector module. The collector module includes collection optics for collecting and focusing the scattered light to form focused scattered light. A collector output slit is positioned at an output of the collector module, through which the collection optics focus the scattered light. The scattered light that is associated with the scanned spot forms an imaged spot at the collector output slit. The collector output slit has a width that is selected to be proportional to the scanned spot size, so as to allow passage of the focused scattered light associated with the scanned spot, and exclude the focused scattered light associated with the workpiece regions other than the desired spot. A collector output varying subsystem varies the collector output slit so as to at least one of minimize passage of Rayleigh light scatter through the collector output slit or optimize a signal to air-scatter-noise ratio.

Scattered light measurement system

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 a variable polarization a polarizing relay assembly arranged to selectively permit the scattered light having a selected polarization orientation to pass along a detector optical axis to a light detection unit in the detection subsystem. The system also features a collector output width varying subsystem for varying the width of an output slit in response to changes in the location of the location scanned on the workpiece.

Inspecting a workpiece using scattered light

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 a variable polarization a polarizing relay assembly arranged to selectively permit the scattered light having a selected polarization orientation to pass along a detector optical axis to a light detection unit in the detection subsystem. They system also features a collector output width varying subsystem for varying the width of an output slit in response to changes in the location of the location scanned on the workpiece.

Inspecting a workpiece using polarization of scattered light

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 a variable scan speed beam scanning subsystem, preferably using an acousto-optic deflector, with beam compensation, so that variable scanning speeds can be achieved. Also included are methods and systems for improving the signal to noise ratio by use of scatter reducing complements, and a system and method for selectively and repeatedly scanning a region of interest on the surface in order to provide additional observations of the region of interest.

System and method for controlling a beam source in a workpiece surface inspection system

System and method for inspecting a workpiece surface using polarization of scattered light

The composition of a particle occurring on the surface of a smooth substrate is identified by impinging the surface with a light beam having a strong P-polarized component at an oblique angle of incidence to the surface, and collecting light scattered from the surface at forward, center, and back locations relative to the portion of the surface impinged by the incident beam. The intensities of the light collected at these locations are measured by detectors and converted into signals, and the magnitudes of the signals are compared to correlations of particle material as a function of the relative magnitudes of the forward-, center-, and back-scatter signals so as to identify the material whose correlation most nearly matches the measured detector signals. Preferably, a ratio of the back detector signal magnitude to forward detector signal magnitude is correlated with particle material and back detector signal magnitude. Alternatively or additionally, a ratio of back detector signal magnitude to center detector signal magnitude is correlated with particle material and back detector signal magnitude. Average particle diameter versus back detector signal magnitude is correlated with particle material.

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Southborough, MA, United States of America

Songping Gao