Kla-tencor Technologies Corporation

Kla Tencor Corporation

Stan Stokowski

David Alles

Damon Floyd Kvamme

Mehdi Vaez-Iravani

Donald Pettibone

Guoheng Zhao

Mehrdad Nikoonahad

Jamie Michael Sullivan

Yalin Xiong

Mark Joseph Wihl

Keith B Wells

Zain Saidin

Chun Lee

Don Pettibone

Steven Biellak

Matthias C Krantz

Zain K Saidin

A plurality of spots forming an M&#xd7;N matrix can be used in a focus system. Specifically, a plurality of identical spots can be simultaneously projected onto the sample. A V(z) curve can be generated for each spot. A robust focus can be determined based on the generated V(z) curves. Using the spot matrix significantly increases the probability that at least one of the plurality of spots in the matrix can provide an unambiguous V(z) curve. Thus, the spot matrix eliminates the need to search for an appropriate site because the spot matrix increases the probability of landing on a 'good' location by a factor of M&#xd7;N.

Enhanced focusing capability on a sample using a spot matrix

Methods for detecting and classifying defects on a reticle are provided. One method includes acquiring images of the reticle at first and second conditions during inspection of the reticle. The first condition is different than the second condition. The method also includes detecting the defects on the reticle using one or more of the images acquired at the first condition. In addition, the method includes classifying an importance of the defects detected on the reticle using one or more of the images acquired at the second condition. The detecting and classifying steps are performed substantially simultaneously during the inspection.

Methods for detecting and classifying defects on a reticle

Systems and methods are provided herein for eliminating speckle noise in die-to-die inspection systems. In one embodiment, an illumination system in accordance with the present invention may include a coherent light source, a diffuser, a first detector, a second detector and a controller. The diffuser may be coupled within an illumination path between the coherent light source and the specimen. In one embodiment, the diffuser may be a rotational diffuser having a variable rotational rate. The first detector may be coupled for detecting a desired position on the specimen. The second detector may be coupled for detecting a rotational position of the diffuser when the desired position on the specimen is detected. The controller may be coupled to: (i) the first and second detectors for determining a difference between the rotational position of the diffuser and the desired position on the specimen, and (ii) the diffuser for adjusting the rotational rate of the diffuser to eliminate the difference.

System and method for reducing speckle noise in die-to-die inspection systems

Methods and systems for inspecting a reticle are provided. In an embodiment, a system may include an inspection subsystem configured to form a first aerial image of the reticle. The first aerial image may be used to detect defects on the reticle. The system may also include a review subsystem coupled to the inspection subsystem. For example, the inspection and review subsystems may have common optics, separate optics and a common stage, or separate stages and a common handler. The review subsystem may be configured to form a second aerial image of the reticle. The second aerial image may be used to analyze the defects. In another embodiment, the system may include an image computer configured to receive image data from the inspection and review subsystems representing the first and second aerial images. The image computer may also be configured to perform one or more functions on the image data.

Methods and systems for reticle inspection and defect review using aerial imaging

Reticle inspection systems are provided. One embodiment includes an optical subsystem configured to produce an aerial image of a reticle by simulating dose as a function of position that would be projected into a resist by an exposure system such that the aerial image is substantially equivalent to an image of the reticle that would be projected into the resist by the exposure system. Another embodiment includes an optical subsystem configured to alter one or more properties of light such as polarization transmitted by a reticle and to project the light onto a detector. An additional embodiment includes an optical subsystem configured to form an intermediate aerial image of a reticle at a numerical aperture approximately equal to a numerical aperture at which an exposure system projects an image of the reticle into a resist and to project the intermediate aerial image onto a detector.

Systems for simulating high NA and polarization effects in aerial images

Methods and systems for inspecting a reticle are provided. In an embodiment, a method may include forming an aerial image of the reticle using a set of exposure conditions. The reticle may include optical proximity correction (OPC) features. The method may also include detecting defects on the reticle by comparing the aerial image to a reference image stored in a database. The reference image may be substantially optically equivalent to an image of the reticle that would be printed on a specimen by an exposure system under the set of exposure conditions. The reference image may not include images of the OPC features. Therefore, a substantial portion of the defects include defects that would be printed onto the specimen by the exposure system using the reticle under the set of exposure conditions. The method may also include indicating the defects that are detected in critical regions of the reticle.

Methods and systems for inspecting reticles using aerial imaging and die-to-database detection

Methods and systems for inspecting a reticle are provided. A method may include forming an aerial image of the reticle with an inspection system at a wavelength different from a wavelength of an exposure system. The method may also include correcting the aerial image for differences between modulation transfer functions (MTF) of the inspection system and the exposure system. In this manner, the corrected aerial image may be substantially equivalent to an image of the reticle that would be printed onto a specimen by the exposure system at the wavelength of the exposure system. In addition, the method may include detecting defects on the reticle using the corrected aerial image. The detected defects may include approximately all of the defects that would be printed onto a specimen by the exposure system using the reticle.

Methods and systems for inspecting reticles using aerial imaging at off-stepper wavelengths

Systems and methods for inspecting a surface of a specimen such as a semiconductor wafer are provided. A system may include an illumination system configured to direct a first beam of light to a surface of the specimen at an oblique angle of incidence and to direct a second beam of light to a surface of the specimen at a substantially normal angle. The system may also include a collection system configured to collect at least a portion of the first and second beams of light returned from the surface of the specimen. In addition, the system may include a detection system. The detection system may be configured to process the collected portions of the first and second beams of light. In this manner, a presence of defects on the specimen may be detected from the collected portions of the first and second beams of light.

Systems and methods for simultaneous or sequential multi-perspective specimen defect inspection

Disclosed are methods and apparatus for altering the phase and/or amplitude of an optical beam within an inspection system using one or more spatial light modulator(s) (SLMs). In one embodiment, an apparatus for optically inspecting a sample with an optical beam is disclosed. The apparatus includes a beam generator for directing an incident optical beam onto the sample whereby at least a first portion of the incident optical beam is directed from the sample as an output beam and a detector positioned to receive at least a portion of the output beam. The detector is also operable to generate an output signal based on the output beam. The apparatus further includes one or more imaging optics for directing the output beam to the detector and a programmable spatial light modulator (SLM) positioned within an optical path of the incident or output beam. The SLM is configurable to adjust a phase and/or amplitude profile of the incident beam or the output beam. The apparatus also has a control system operable to configure the SLM to alter the phase and/or amplitude profile of the incident beam or the output beam. For example, the SLM may be configured to alter the illumination profile of the incident beam to achieve different inspection modes. In another example, the SLM may be configured to alter the phase and/or amplitude profile of the output beam so as to substantially eliminate aberrations produced by the imaging optics. In other embodiments, the apparatus may include two or more SLM's which are configurable to alter the phase and/or amplitude profile of both the incident beam and the output beam.

Apparatus and methods for removing optical abberations during an optical 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.

Growing community of inventors

Danville, CA, United States of America

Stan Stokowski