Kla Tencor Corporation

Ian T Kohl

Neil Judell

Richard Earl Bills

Songping Gao

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.

Growing community of inventors

Rio Rancho, NM, United States of America

Ian T Kohl