Onto Innovation Inc.

Kla Tencor Corporation

John F Lesoine

Shankar Krishnan

Leonid Poslavsky

Lanhua Wei

Hidong Kwak

Mikhail M Sushchik

Malik Sadiq

Daniel T Thompson

Amit Shachaf

Pedro Vagos

Kenneth Edward James, Jr

An ellipsometer includes a focusing system that uses an image of the measurement spot to determine a best focal position for the ellipsometer. The focus signal is produced by splitting off the ellipsometer measurement spot before the signal is analyzed by a polarizer thereby avoiding imagining the spot with a modulated intensity. The focus signal is imaged on a sensor array and based on the position of the spot on the sensor array, the focal position of the ellipsometer may be determined. A single image may be used to determine the focal position of the ellipsometer permitting a real time focus position measurement.

Beamsplitter based ellipsometer focusing system

The light from an optical metrology device is focused into a measurement spot on a sample using a focusing system. The focusing system uses an image of the light reflected from the measurement spot to determine a best focal position at a desired position of the sample. The focusing system selects a characteristic of reflected light, such as polarization state or wavelengths, to use for focusing. The characteristic of the reflected light that is selected for use in determining focal position is affected different by different portions of the sample. For example, light reflected from a top surface of a sample may have a different characteristic than light reflected by an underlying layer. The selected characteristic of the reflected light is used by the focusing system to focus the measurement spot at the top surface or an underlying layer of the sample.

Focus system for oblique optical metrology device

An optical metrology device uses a multi-wavelength beam of light that has azimuthally varying polarization states and/or phase states, referred to as a vortex beam. The metrology device focuses the vortex beam on a sample under test over a large range of angles of incidence. The metrology device may detect an image of the vortex beam reflected from the sample and measure the polarization state of the return light as function of the angle of incidence and the azimuth angle, which may be further measured at a plurality of different wavelengths. The vortex beam includes azimuthally varying polarization states, thereby enabling measurement of all desired polarization states without requiring the use of moving optical components. The polarization state information detected over multiple angles of incidence and wavelengths provides data with which an accurate determination of one or more characteristics of a sample may be determined.

Vortex polarimeter

Methods and systems for matching measurement spectra across one or more optical metrology systems are presented. The values of one or more system parameters used to determine the spectral response of a specimen to a measurement performed by a target metrology system are optimized. The system parameter values are optimized such that differences between measurement spectra generated by a reference system and the target system are minimized for measurements of the same metrology targets. Methods and systems for matching spectral errors across one or more optical metrology systems are also presented. A trusted metrology system measures the value of at least one specimen parameter to minimize model errors introduced by differing measurement conditions present at the time of measurement by the reference and target metrology systems. Methods and systems for parameter optimization based on low-order response surfaces are presented to reduce the compute time required to refine system calibration parameters.

Metrology system calibration refinement

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San Jose, CA, United States of America

John F Lesoine