Kla Tencor Corporation

Kla-tencor Technologies Corporation

Kla Corporation

Kla-tenor Corp.

Daniel Kandel

Vladimir Levinski

Amnon Manassen

Joel L Seligson

Barak Bringoltz

Ohad Bachar

Andrew V Hill

Noam Sapiens

Alexander Svizher

Michael E Adel

Yoel Feler

Ilan Sela

Eran Amit

Daria Negri

Mark Ghinovker

Efraim Rotem

Nuriel Amir

Guy Cohen

Boris Golovanevsky

Yung-Ho Alex Chuang

Andrei V Shchegrov

Zeev Bomzon

Yuri Paskover

Lawrence D Rotter

Meir Aloni

Ady Levy

Ilya Bezel

Stilian Pandev

Anatoly Shchemelinin

Mark Davis Smith

Nadav Gutman

Liran Yerushalmi

John Charles Robinson

Mark Wagner

Gregory Brady

Derrick A Shaughnessy

Avi Abramov

Pavel Izikson

Tal Marciano

Dana Klein

Tzahi Grunzweig

Muzammil A Arain

Leonid Poslavsky

Walter Dean Mieher

Roie Volkovich

Michael Friedmann

David Y Wang

Kenneth P Gross

Amir Widmann

Jonathan M Madsen

Johannes D De Veer

DongSub Choi

Dzmitry Sanko

Moshe Markowitz

Guy Ben Dov

Nadav Carmel

Hadar Shalmoni

Ofer Zaharan

Tal Itzkovich

Myungjun Lee

Amit Shaked

Dror Alumot

Yaron Ish-Shalom

Moshe Baruch

Paykin Irina

Anatoly A Vasiliev

James Andrew Allen

Oleg Shulepov

Maxim Khokhlov

Oleg Tsibulevsky

Jiyou Fu

David Tien

Evgeni Gurevich

Andy Hill

Dongsub Choi

Anatoly Vasiliev

Boris Efraty

Noga Sella

Ido Adam

Aviv Frommer

Tal Yaziv

Lilach Saltoun

Tom Leviant

Vidya Ramanathan

Janay Camp

Ori Tadmor

Oded Kaminsky

Amir Handelman

Irina Vakshtein

Eliav Benisty

Mohamed El Kodadi

Ze'ev Lindenfeld

Dzimtry Sanko

Victoria Naipak

Zeng Zhao

Irina Paykin

Feler Yoel

Shakar Krishnan

Moshe Cooper

Roee Sulimarski

Metrology methods, modules and targets are provided, for measuring tilted device designs. The methods analyze and optimize target design with respect to the relation of the Zernike sensitivity of pattern placement errors (PPEs) between target candidates and device designs. Monte Carlo methods may be applied to enhance the robustness of the selected target candidates to variation in lens aberration and/or in device designs. Moreover, considerations are provided for modifying target parameters judiciously with respect to the Zernike sensitivities to improve metrology measurement quality and reduce inaccuracies.

Metrology target design for tilted device designs

The present invention may include acquiring a plurality of overlay metrology measurement signals from a plurality of metrology targets distributed across one or more fields of a wafer of a lot of wafers, determining a plurality of overlay estimates for each of the plurality of overlay metrology measurement signals using a plurality of overlay algorithms, generating a plurality of overlay estimate distributions, and generating a first plurality of quality metrics utilizing the generated plurality of overlay estimate distributions, wherein each quality metric corresponds with one overlay estimate distribution of the generated plurality of overlay estimate distributions, each quality metric a function of a width of a corresponding generated overlay estimate distribution, each quality metric further being a function of asymmetry present in an overlay metrology measurement signal from an associated metrology target.

Method and system for providing a quality metric for improved process control

An overlay metrology system includes one or more processors coupled to an illumination source to direct illumination to a sample and a detector to capture diffracted orders of radiation from the sample. The system may generate overlay sensitivity calibration parameters based on differential measurements of a calibration target including two overlay target cells on the sample, where first-layer target elements and second-layer target elements of the overlay target cells are distributed with a common pitch along a measurement direction and are misregistered with a selected offset value in opposite directions. The system may further determine overlay measurements based on differential measurements of additional overlay target cells with two wavelengths, where first-layer target elements and second-layer target elements of the additional overlay target cells are distributed with the common pitch and are formed to overlap symmetrically. The system may further adjust the overlay measurements with the overlay sensitivity calibration parameters.

Device metrology targets and methods

Methods are provided for deriving a partially continuous dependency of metrology metric(s) on recipe parameter(s), analyzing the derived dependency, determining a metrology recipe according to the analysis, and conducting metrology measurement(s) according to the determined recipe. The dependency may be analyzed in form of a landscape such as a sensitivity landscape in which regions of low sensitivity and/or points or contours of low or zero inaccuracy are detected, analytically, numerically or experimentally, and used to configure parameters of measurement, hardware and targets to achieve high measurement accuracy. Process variation is analyzed in terms of its effects on the sensitivity landscape, and these effects are used to characterize the process variation further, to optimize the measurements and make the metrology both more robust to inaccuracy sources and more flexible with respect to different targets on the wafer and available measurement conditions.

Method of analyzing and utilizing landscapes to reduce or eliminate inaccuracy in overlay optical metrology

Metrology methods are provided, which comprise identifying overlay critical patterns in a device design, the overlay critical patterns having an overlay sensitivity to process variation above a specified threshold that depends on design specifications; and using metrology targets that correspond to the identified overlay critical patterns. Alternatively or complementarily, metrology methods comprise identifying yield critical patterns according to a corresponding process window narrowing due to specified process variation, wherein the narrowing is defined by a dependency of edge placement errors (EPEs) of the patterns on process parameters. Corresponding targets and measurements are provided.

Metrology using overlay and yield critical patterns

Metrology methods, systems and targets are provided, which implement a side by side paradigm. Adjacent cells with periodic structures are used to extract the overlay error, e.g., by introducing controllable phase shifts or image shifts which enable algorithmic computation of the overlay. The periodic structures are designed to exhibit a rotational symmetry to support the computation and reduce errors.

Symmetric target design in scatterometry overlay metrology

Metrology methods and targets are provided, that expand metrological procedures beyond current technologies into multi-layered targets, quasi-periodic targets and device-like targets, without having to introduce offsets along the critical direction of the device design. Several models are disclosed for deriving metrology data such as overlays from multi-layered target and corresponding configurations of targets are provided to enable such measurements. Quasi-periodic targets which are based on device patterns are shown to improve the similarity between target and device designs, and the filling of the surroundings of targets and target elements with patterns which are based on device patterns improve process compatibility. Offsets are introduced only in non-critical direction and/or sensitivity is calibrated to enable, together with the solutions for multi-layer measurements and quasi-periodic target measurements, direct device optical metrology measurements.

Angle-resolved reflectometers and reflectometry methods are provided, which comprise a coherent light source, an optical system arranged to scan a test pattern using a spot of coherent light from the light source to yield realizations of the light distribution in the collected pupil, wherein the spot covers a part of the test pattern and the scanning is carried out optically or mechanically according to a scanning pattern, and a processing unit arranged to generate a composite image of the collected pupil distribution by combining the pupil images. Metrology systems and methods are provided, which reduce diffraction errors by estimating, quantitatively, a functional dependency of measurement parameters on aperture sizes and deriving, from identified diffraction components of the functional dependency which relate to the aperture sizes, correction terms for the measurement parameters with respect to the measurement conditions.

Scanning in angle-resolved reflectometry and algorithmically eliminating diffraction from optical metrology

A system for measuring overlay from a multi-layer overlay target for use in imaging based metrology is disclosed. The system is configured for measuring overlay from a multi-layer overly target that includes three or more target structures, wherein a first target structure is disposed in a first process layer, a second target structure is disposed in a second process layer, and at least a third target structure is disposed in at least a third process layer. The system includes an illumination source configured to illuminate the target structures of the multi-layer overlay target, a detector configured to collect light reflected from the target structures, and one or more processors configured to execute a set of program instructions to determine overlay error between two or more structures based on the collected light from the plurality of targets.

Multi-layer overlay metrology target and complimentary overlay metrology measurement systems

Contrast enhancement in a metrology tool may include generating a beam of illumination, directing a portion of the generated beam onto a surface of a spatial light modulator (SLM), directing at least a portion of the generated beam incident on the surface of the SLM through an aperture of an aperture stop and onto one or more target structures of one or more samples, and generating a selected illumination pupil function of the illumination transmitted through the aperture utilizing the SLM in order to establish a contrast level of one or more field images of the one or more target structures above a selected contrast threshold, and performing one or more metrology measurements on the one or more target structures utilizing the selected illumination pupil function.

Structured illumination for contrast enhancement in overlay metrology

Metrology systems and methods are provided herein, which comprise an optical element that is positioned between an objective lens of the system and a target. The optical element is arranged to enhance evanescent modes of radiation reflected by the target. Various configurations are disclosed: the optical element may comprise a solid immersion lens, a combination of Moir&#xe9;-elements and solid immersion optics, dielectric-metal-dielectric stacks of different designs, and resonating elements to amplify the evanescent modes of illuminating radiation. The metrology systems and methods are configurable to various metrology types, including imaging and scatterometry methods.

Near field metrology

A method for target measurement is provided which comprises designing a reflection-symmetric target and measuring overlays of the target along at least one reflection symmetry direction of the target. Also, a tool calibration method comprising calibrating a scatterometry measurement tool with respect to a reflection symmetry of a reflection symmetric target. Further provided are methods of measuring scatterometry overlay using first order and zeroth order scatterometry measurements of a reflection-symmetric scatterometry targets. Also, a scatterometry target comprising a reflection-symmetric target having two cells in each of at least two measurement directions, wherein respective cells have different offsets along one measurement direction and similar offsets along other measurement directions. Further, a scatterometry measurement system comprising a reflection symmetric illumination and calibrated to measure reflection symmetric targets. Also, metrology tool comprising an illumination path and a collection path of the tool which are symmetric to reflection symmetries of a target.

Reflection symmetric scatterometry overlay targets and methods

Target design methods, targets as well as scanner aberration methods and device design improvements are provided. Metrology targets may be designed by identifying at least two geometric elements in a specified device design, and designing corresponding at least two target cells of an overlay metrology target to have structures related to the at least two geometric elements. Non-printed filling elements may be added to target or device designs which exhibit large spaces (e.g., larger than twice the minimal design rule pitch) in order to avoid placement error and other inaccuracies. Scanner aberrations themselves may be measured using corresponding targets as well.

Achieving a small pattern placement error in metrology targets

A system for providing illumination to a measurement head for optical metrology is configured to combine illumination beams from a plurality of illumination sources to deliver illumination at one or more selected wavelengths to the measurement head. The intensity and/or spatial coherence of illumination delivered to the measurement head is controlled. Illumination at one or more selected wavelengths is delivered from a broadband illumination source configured for providing illumination at a continuous range of wavelengths.

Systems for providing illumination in optical metrology

Objective lenses and corresponding optical systems and metrology tools, as well as methods are provided. Objective lenses comprise a central region conforming to specified imaging requirements and a peripheral region conforming to specified scatterometry requirements. The optical systems may comprise common-path optical elements configured to handle both imaging and scatterometry signals received through the objective lens. Using a single objective lens simplifies the design of the optical system while maintaining, simultaneously, the performance requirements for imaging as well as for scatterometry.

Compound objectives for imaging and scatterometry overlay

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Aseret, Israel

Daniel Kandel