Kla Tencor Corporation

Kla Corporation

Kla-tencor Technologies Corporation

Donald Pettibone

Ivan Maleev

Chuanyong Huang

Daniel Ivanov Kavaldjiev

Yung-Ho Alex Chuang

Guoheng Zhao

Christian Wolters

Stephen Biellak

Damon Floyd Kvamme

Anatoly Romanovsky

Qing Li

Bret Whiteside

Stan Stokowski

John Fielden

David Lee Brown

David W Shortt

Zhiwei Xu

Jehn-Huar Chern

Kurt Lindsay Haller

Chunsheng J Huang

Oscar G Florendo

Guowu Zheng

Devis Contarato

Chunhai Wang

Jijen Vazhaeparambil

Frank Li

Li-Min Chen

Martin Brutsch

Chun Lee

Emanuel Saerchen

Steve (Yifeng) Cui

Buzz Graves

Matthias C Krantz

An optical system for controlling polarization may include an illumination source to illuminate a surface of a sample, a set of collection optics to collect illumination from the surface of a sample, and a wave plate having a spatially-varying surface profile along a thickness direction positioned at a pupil plane of the set of collection optics, where the spatially-varying surface profile of the wave plate is configured to control polarization rotation as a continuous function of transverse position, and where the spatially-varying surface profile is selected to rotate light scattered from a surface of a sample to a selected polarization angle. The system may further include a linear polarizer oriented to block light with the selected polarization angle, and a sensor to detect illumination transmitted through the linear polarizer.

System, method and apparatus for polarization control

A system for laser enhanced voltage contrast using an optical fiber is provided. The system includes a vacuum chamber with a stage that secures a wafer. A laser light source outside the vacuum chamber directs light to an optical fiber. The optical fiber transmits all wavelengths of light from the laser light source into the vacuum chamber through a wall of the vacuum chamber.

Delivery of light into a vacuum chamber using an optical fiber

A system is disclosed. The system includes a stage assembly configured to receive a specimen and maintain a height of the specimen at a first working distance height during a first characterization mode and an additional working distance height during an additional characterization mode. The system further includes an illumination source configured to generate an illumination beam. The system further includes an illumination arm including a set of optical elements configured to direct a portion of the illumination beam including illumination of a first wavelength to the specimen during the first characterization mode, and direct a portion of the illumination beam including illumination of an additional wavelength to the specimen during the additional characterization mode. The system further includes a detector assembly configured to receive illumination emanated from the specimen, and a controller configured to determine a specimen height value based on the illumination received by the detector assembly.

Multiple working distance height sensor using multiple wavelengths

A polarization control device includes a first wave plate having a first surface profile and a second wave plate having a second surface profile complementary to the first surface profile. The optical axis of the first wave plate is orthogonal to the optical axis of the second wave plate. The first wave plate and the second wave plate are positioned to align the first surface profile with the second surface profile and maintain a constant thickness across the polarization control device. The first wave plate and the second wave plate may control polarization rotation as a continuous function of transverse position across a pupil plane of an optical system. The first wave plate and the second wave plate are separated by a sufficiently small distance so as to limit wave front distortion below a selected level.

Stray and air scattered light can be reduced by configuring a size of the collection area of a sensor, which reduces a source of sensitivity-limiting noise in the system. By adjusting a size of the collection area, stray deep ultraviolet light and air-scattered deep ultraviolet light can be reduced. A servo can control a position of an illumination spot that is collected by the time delay and integration sensor.

Minimizing filed size to reduce unwanted stray light

An inspection system and methods in which analog image data values (charges) captured by an image sensor are binned (combined) before or while being transmitted as output signals on the image sensor's output sensing nodes (floating diffusions), and in which an ADC is controlled to sequentially generate multiple corresponding digital image data values between each reset of the output sensing nodes. According to an output binning method, the image sensor is driven to sequentially transfer multiple charges onto the output sensing nodes between each reset, and the ADC is controlled to convert the incrementally increasing output signal after each charge is transferred onto the output sensing node. According to a multi-sampling method, multiple charges are vertically or horizontally binned (summed/combined) before being transferred onto the output sensing node, and the ADC samples each corresponding output signal multiple times. The output binning and multi-sampling methods may be combined.

Dark-field inspection using a low-noise sensor

Methods and systems for reducing illumination intensity while scanning over large particles are presented herein. A surface inspection system determines the presence of a large particle in the inspection path of a primary measurement spot using a separate leading measurement spot. The inspection system reduces the incident illumination power while the large particle is within the primary measurement spot. The primary measurement spot and the leading measurement spot are separately imaged by a common imaging collection objective onto one or more detectors. The imaging based collection design spatially separates the image of the leading measurement spot from the image of the primary measurement spot at one or more wafer image planes. Light detected from the leading measurement spot is analyzed to determine a reduced power time interval when the optical power of the primary illumination beam and the leading illumination beam are reduced.

Surface defect inspection with large particle monitoring and laser power control

A luminescent tag based defect detection system comprises a luminescent tag attachment assembly, an illumination source, one or more detectors, and a set of optical elements. The luminescent tag attachment assembly exposes a sample to one or more luminescent tag materials selectively attached to one or more defects on the sample. The illumination source generates illumination including one or more wavelengths corresponding to the one or more absorption spectra associated with the one or more luminescent tags. At least a portion of the set of optical elements directs illumination from the illumination source to the sample, and at least a portion of the set of optical elements directs illumination emitted from the one or more luminescent tag materials to the one or more detectors. A luminescent tag based defect detection system may also include a luminescent tag removal assembly to remove the luminescent tags after detection.

System and method for luminescent tag based wafer inspection

A wafer scanning system includes imaging collection optics to reduce the effective spot size. Smaller spot size decreases the number of photons scattered by the surface proportionally to the area of the spot. Air scatter is also reduced. TDI is used to produce a wafer image based on a plurality of image signals integrated over the direction of linear motion of the wafer. An illumination system floods the wafer with light, and the task of creating the spot is allocated to the imaging collection optics.

TDI sensor in a darkfield system

Improvement of wafer surface inspection sensitivity includes acquiring a first inspection image from the surface of the wafer, generating a reference image by applying a thresholding function to the first image in order to isolate a speckle signal component of the first image induced by wafer surface roughness, acquiring one or more measurement inspection images from the surface of the wafer, and generating a difference image by subtracting the generated one or more reference images from the acquired one or more measurement inspection images.

Method and system for improving wafer surface inspection sensitivity

An inspection apparatus for simultaneous dark field (DF) and differential interference contrast (DIC) inspection includes an illumination source and a sample stage configured to secure a sample. The inspection apparatus includes a first sensor, a second sensor and an optical sub-system. The optical sub-system includes an objective, one or more optical elements arranged to direct, through the objective, illumination from the one or more illumination sources to a surface of the sample. The objective is configured to collect a signal from the surface of the sample, wherein the collected signal includes a scattering-based signal and/or a phase-based signal from the sample. The inspection apparatus includes one or more separation optical elements arranged to spatially separate the collected signal into a DF signal and a DIC signal by directing the DF signal and the DIC signal along a DF path and DIC path respectively.

System and method for simultaneous dark field and phase contrast inspection

Provided are apparatus and methods for detecting phase defects. The invention relies generally on the distortion of light as it passes through defects in phase shift masks to detect these defects. Light traveling through a defect, such as a bump in an etched area will travel at a different angle than light traveling through air. In order to enhance the signals generated from the defects, the invention in several embodiments provides a multiple element detector having at least four elements, arranged in a radially symmetric configuration. Individual elements of the detector are selected to form a differential signal based on the configuration of pattern lines in the area proximate to the defect. The resulting differential signal is used to generate an image signal and to identify phase defects.

Method and system for detecting phase defects in lithographic masks and semiconductor wafers

Provided are apparatus and methods for detecting phase defects. The invention relies generally on the distortion of light as it passes through defects in phase shift masks to detect these defects. Light traveling through a defect, such as a bump in an etched area will travel at a different rate than light traveling through air. In order to enhance the signals generated from the defects, the invention in several embodiments provides a defocused light inspection beam by setting the focus of the beam to a level above or below the photomask subject to inspection. The light from the photomask is collected by a detector split into at least two portions, each generating a signal. A resulting differential signal produced from the signals generated at each of the two detector portions is used to determine whether a defect in the photomask is present, in one embodiment, by generating an image from the resulting signal.

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San Jose, CA, United States of America

Donald Pettibone