Kla Tencor Corporation

Kla-tencor Technologies Corporation

Hidong Kwak

Shankar Krishnan

Leonid Poslavsky

Gary Janik

Torsten Rudolf Kaack

Ward RDell Dixon

Shing Lee

Haixing Zou

Mehrdad Nikoonahad

Lanhua Wei

Ning-Yi Neil Wang

Mikhail M Sushchik

John F Lesoine

Jagjit Sandhu

Malik Sadiq

Guoheng Zhao

Ying Gao

Damon Floyd Kvamme

Kevin A Peterlinz

Sergio Edelstein

Johannes D De Veer

Liang-Guo Wang

James McWhirter

Daniel R Hennigan

Fuming Wang

Patrick M Maxton

Zhiming Jiang

Kenneth Edward James, Jr

Dan G Georgesco

Esen Salcin

Uri Greenberg

Bernard Lautee

Jennming James Chen

Torsten Kaack

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

Methods and systems for calibrating system parameter values of a target inspection system are presented. Spectral Error Based Calibration (SEBC) increases consistency among inspection systems by minimizing differences in the spectral error among different inspection systems for a given specimen or set of specimens. The system parameter values are determined such that differences between a spectral error associated with a measurement of a specimen by the target inspection system and a spectral error associated with a measurement of the same specimen by a reference inspection system are minimized. In some examples, system parameter values are calibrated without modifying specimen parameters. Small inaccuracies in specimen parameter values have little effect on the calibration because the target system and the reference system both measure the same specimen or set of specimens. By performing SEBC over a set of specimens, the resulting calibration is robust to a wide range of specimens under test.

Spectral matching based calibration

Methods and systems for performing single wavelength ellipsometry (SWE) measurements with reduced measurement spot size are presented herein. In one aspect, a pupil stop is located at or near a pupil plane in the collection optical path to reduce sensitivity to target edge diffraction effects. In another aspect, a field stop is located at or near an image plane conjugate to the wafer plane in the collection optical path to reduce sensitivity to undesired optical-structural interactions. In another aspect, a linear polarizer acting on the input beam of the SWE system includes a thin, nanoparticle based polarizer element. The nanoparticle based polarizer element improves illumination beam quality and reduces astigmatism on the wafer plane. The pupil and field stops filter out unwanted light rays before reaching the detector. As a result, measurement spot size is reduced and tool-to-tool matching performance for small measurement targets is greatly enhanced.

Single wavelength ellipsometry with improved spot size capability

A local purging tool for purging a portion of a surface of a wafer with purging gas is disclosed. The purging tool includes a purging chamber configured to contain purging gas within a cavity of the purging chamber, a permeable portion of a surface of the purging chamber configured to diffuse purging gas from the cavity of the chamber to a portion of a surface of a wafer, and an aperture configured to transmit illumination received from an illumination source to a measurement location of the portion of the surface of the wafer and further configured to transmit illumination reflected from the measurement location to a detector.

Atmospheric molecular contamination control with local purging

Ellipsometry systems and ellipsometry data collection methods with improved stabilities are disclosed. In accordance with the present disclosure, multiple predetermined, discrete analyzer angles are utilized to collect ellipsometry data for a single measurement, and data regression is performed based on the ellipsometry data collected at these predetermined, discrete analyzer angles. Utilizing multiple discrete analyzer angles for a single measurement improves the stability of the ellipsometry system.

Multi-analyzer angle spectroscopic ellipsometry

An illumination subsystem configured to provide illumination for a measurement system includes first and second light sources configured to generate light for measurements in different wavelength regimes. The illumination subsystem also includes a TIR prism configured to be moved into and out of an optical path from the first and second light sources to the measurement system. If the TIR prism is positioned out of the optical path, light from only the first light source is directed along the optical path. If the TIR prism is positioned in the optical path, light from only the second light source is directed along the optical path. Various measurement systems are also provided. One measurement system includes an optical subsystem configured to perform measurements of a specimen using light in different wavelength regimes directed along a common optical path. The different wavelength regimes include vacuum ultraviolet, ultraviolet, visible, and near infrared wavelength regimes.

Measurement systems configured to perform measurements of a specimen and illumination subsystems configured to provide illumination for a measurement system

An optical method and system for measuring characteristics of a sample using a broadband metrology tool in a purge gas flow environment are disclosed. In the method a beam path for the metrology tool is purged with purge gas at a first flow rate. A surface of the sample is illuminated by a beam of source radiation having at least one wavelength component in a vacuum ultraviolet (VUV) range and/or at least one wavelength component in an ultraviolet-visible (UV-Vis) range. A flow rate of a purge gas is adjusted between the first flow rate for metrology measurements made when the source radiation is in the VUV spectral region and a second flow rate for metrology measurements made when the source radiation is in the UV-Vis spectral region. The system includes a light source, illumination optics, collection optics, detector, a purge gas source and a controller. The purge gas source is configured to supply a flow of purge gas to a beam path in the light source and/or illumination optics and/or sample and/or collection optics and/or detector. The controller is configured to control a flow rate of the purged gas flow in response to an output signal from the detector.

Purge gas flow control for high-precision film measurements using ellipsometry and reflectometry

In an optical system measuring sample characteristics, by reducing the amount of ambient absorbing gas or gases and moisture present in at least a portion of the illumination and detection paths experienced by vacuum ultraviolet (VUV) radiation used in the measurement process, the attenuation of such wavelength components can be reduced. Such reduction can be accomplished by a process without requiring the evacuation of all gases and moisture from the measurement system. In one embodiment, the reduction can be accomplished by displacing at least some of the absorbing gas(es) and moisture present in at least a portion of the measuring paths so as to reduce the attenuation of VUV radiation. In this manner, the sample does not need to be placed in a vacuum, thereby enhancing system throughput.

Optical system for measuring samples using short wavelength radiation

In one embodiment, a probe pulse is first stretched into a pulse of longer duration. The probe pulse comprises a plurality of wavelength components in a bandwidth, so that each temporal portion of the converted pulse corresponds to and comprises one of the wavelength components. This converted pulse is supplied to the sample at the time when it is affected by the disturbance of the sample caused by a pump pulse. Changes in characteristics of the sample at the wavelength components of the temporal portions of the converted pulse are then detected after the converted pulse has been modified by the sample. Such changes are then analyzed to derive characteristics of the sample. In another embodiment, a converter passes to a detector radiation from a probe beam that has been modified by the sample during a temporal sequence of time intervals, where the time intervals correspond to displacement in a spatial record. The radiation passed comprises radiation from the probe beam when it is affected by the disturbance in the sample caused by a pump pulse. The output of the detector is then analyzed to determine the characteristics of the sample.

Time-resolved measurement technique using radiation pulses

Methods and systems for preparing a sample for thin film analysis are provided. One system includes an energy beam source configured to generate an energy beam. The system also includes an energy beam delivery subsystem configured to direct the energy beam to a sample and to modify the energy beam such that the energy beam has a substantially flat-top profile on the sample. The energy beam removes a portion of a contaminant layer on the sample to expose an analysis area of a thin film on the sample. One method includes generating an energy beam and modifying the energy beam such that the energy beam has a substantially flat-top profile. The method also includes directing the energy beam to a sample. The energy beam removes a portion of a contaminant layer on the sample to expose an analysis area of a thin film on the sample.

Methods and systems for preparing a sample for thin film analysis

An apparatus capable of measuring topography and transparent film thickness of a patterned metal-dielectric layer on a substrate without contact with the layer. A broadband interferometer measures an absolute phase of reflection at a plurality of wavelengths from a plurality of locations within a field of view on the metal-dielectric patterned layer on the substrate, and produces reflection phase data. An analyzer receives the reflection phase data and regresses the transparent film thickness and the topography at each of the plurality of locations from the reflection phase data. In this manner, the apparatus is not confused by the phase changes produced in the reflected light by the transparent layers, because the thickness of the transparent layers are determined by using the reflection phase data from multiple wavelengths. Further, the surface topography of the layer, whether it be opaque or transparent is also determinable. Thus, the present invention provides a means by which both transparent layer thickness and topography can be determined on an array surface of transparent and opaque layers, without contacting the surface of the layers.

Optical film topography and thickness measurement

Growing community of inventors

San Jose, CA, United States of America

Hidong Kwak