Patents by Inventor Raghav Babulnath

Raghav Babulnath has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 10712289
    Abstract: Various embodiments for detecting defects on a wafer are provided. One method includes acquiring output generated by an inspection system for a wafer during an inspection process that is performed after at least first and second process steps have been performed on the wafer. The first and second process steps include forming first and second portions, respectively, of a design on the wafer. The first and second portions of the design are mutually exclusive in space on the wafer. The method also includes detecting defects on the wafer based on the output and determining positions of the defects with respect to the first and second portions of the design. In addition, the method includes associating different portions of the defects with the first or second process step based on the positions of the defects with respect to the first and second portions of the design.
    Type: Grant
    Filed: July 27, 2015
    Date of Patent: July 14, 2020
    Assignee: KLA-Tencor Corp.
    Inventors: Oksen Toros Baris, Raghav Babulnath
  • Patent number: 10620134
    Abstract: Methods and systems for creating a sample of defects for a specimen are provided. One method includes detecting defects on a specimen based on output generated by a detector of an output acquisition subsystem. For the defects detected in an array region on the specimen, where the array region includes multiple array cell types, the method includes stacking information for the defects based on the multiple array cell types. The stacking includes overlaying design information for only a first of the multiple array cell types with the information for only the defects detected in the first of the multiple array cell types. In addition, the method includes selecting a portion of the detected defects based on results of the stacking thereby creating a sample of the detected defects.
    Type: Grant
    Filed: July 26, 2018
    Date of Patent: April 14, 2020
    Assignee: KLA-Tencor Corp.
    Inventors: Vidyasagar Anantha, Manikandan Mariyappan, Raghav Babulnath, Gangadharan Sivaraman, Satya Kurada, Thirupurasundari Jayaraman, Prasanti Uppaluri, Srikanth Kandukuri
  • Publication number: 20190346375
    Abstract: Methods and systems for creating a sample of defects for a specimen are provided. One method includes detecting defects on a specimen based on output generated by a detector of an output acquisition subsystem. For the defects detected in an array region on the specimen, where the array region includes multiple array cell types, the method includes stacking information for the defects based on the multiple array cell types. The stacking includes overlaying design information for only a first of the multiple array cell types with the information for only the defects detected in the first of the multiple array cell types. In addition, the method includes selecting a portion of the detected defects based on results of the stacking thereby creating a sample of the detected defects.
    Type: Application
    Filed: July 26, 2018
    Publication date: November 14, 2019
    Inventors: Vidyasagar Anantha, Manikandan Mariyappan, Raghav Babulnath, Gangadharan Sivaraman, Satya Kurada, Thirupurasundari Jayaraman, Prasanti Uppaluri, Srikanth Kandukuri
  • Patent number: 10127652
    Abstract: Systems and methods for classifying defects detected on a wafer are provided. One method includes detecting defects on a wafer based on output generated for the wafer by an inspection system. The method also includes determining one or more attributes for at least one of the defects based on portions of a standard reference image corresponding to the at least one of the defects. The method further includes classifying the at least one of the defects based at least in part on the one or more determined attributes.
    Type: Grant
    Filed: February 2, 2015
    Date of Patent: November 13, 2018
    Assignee: KLA-Tencor Corp.
    Inventors: Lisheng Gao, Avijit K. Ray-Chaudhuri, Raghav Babulnath, Kenong Wu
  • Patent number: 9996942
    Abstract: Methods and systems for determining a position of output generated by an inspection subsystem in design data space are provided. In general, some embodiments described herein are configured for substantially accurately aligning inspection subsystem output generated for a specimen to a design for the specimen despite deformation of the design in the inspection subsystem output. In addition, some embodiments are configured for generating and/or using alignment targets that can be shared across multiple specimens of the same layer and design rule for alignment of inspection subsystem output generated for a specimen to a design for the specimen.
    Type: Grant
    Filed: March 17, 2016
    Date of Patent: June 12, 2018
    Assignee: KLA-Tencor Corp.
    Inventors: Santosh Bhattacharyya, Pavan Kumar, Lisheng Gao, Thirupurasundari Jayaraman, Raghav Babulnath, Srikanth Kandukuri, Gangadharan Sivaraman, Karthikeyan Subramanian, Raghavan Konuru, Rahul Lakhawat
  • Patent number: 9865512
    Abstract: Methods and systems for dynamic design attributes for wafer inspection are provided. One method includes, at run time of a wafer inspection recipe, prompting a user of a wafer inspection tool on which the wafer inspection recipe is performed for information for a design based binning (DBB) process. The information includes one or more formulae for calculating design attributes from a design for a wafer. The design attributes are used to bin the defects in the DBB process. The method also includes performing inspection of a wafer according to an updated wafer inspection recipe. Performing the inspection includes binning defects detected on the wafer according to the DBB process in the updated wafer inspection recipe.
    Type: Grant
    Filed: April 3, 2014
    Date of Patent: January 9, 2018
    Assignee: KLA-Tencor Corp.
    Inventors: Thirupurasundari Jayaraman, Raghav Babulnath
  • Patent number: 9835566
    Abstract: Methods and systems for generating inspection results for a specimen with an adaptive nuisance filter are provided. One method includes selecting a portion of events detected during inspection of a specimen having values for at least one feature of the events that are closer to at least one value of at least one parameter of the nuisance filter than the values for at least one feature of another portion of the events. The method also includes acquiring output of an output acquisition subsystem for the sample of events, classifying the events in the sample based on the acquired output, and determining if one or more parameters of the nuisance filter should be modified based on results of the classifying. The nuisance filter or the modified nuisance filter can then be applied to results of the inspection of the specimen to generate final inspection results for the specimen.
    Type: Grant
    Filed: March 1, 2016
    Date of Patent: December 5, 2017
    Assignee: KLA-Tencor Corp.
    Inventors: Ardis Liang, Martin Plihal, Raghav Babulnath, Sankar Venkataraman
  • Patent number: 9766187
    Abstract: Systems and methods for detecting defects on a wafer are provided. One method includes generating test image(s) for at least a portion of an array region in die(s) on a wafer from frame image(s) generated by scanning the wafer with an inspection system. The method also includes generating a reference image for cell(s) in the array region from frame images generated by the scanning of the wafer. In addition, the method includes determining difference image(s) for at least one cell in the at least the portion of the array region in the die(s) by subtracting the reference image from portion(s) of the test image(s) corresponding to the at least one cell. The method further includes detecting defects on the wafer in the at least one cell based on the difference image(s).
    Type: Grant
    Filed: August 27, 2015
    Date of Patent: September 19, 2017
    Assignee: KLA-Tencor Corp.
    Inventors: Hong Chen, Kenong Wu, Eugene Shifrin, Masatoshi Yamaoka, Gangadharan Sivaraman, Raghav Babulnath, Satya Kurada, Shuo Sun
  • Publication number: 20170103517
    Abstract: Methods and systems for design based sampling and binning for yield critical defects are provided. One method includes aligning each image patch in each inspection image frame generated for a wafer by an optical subsystem of an inspection system to design information for the wafer. The method also includes deriving multiple layer design attributes at locations of defects detected in the image patches. In addition, the method includes building a decision tree with the multiple layer design attributes. The decision tree is used to separate the defects into bins with different yield impacts on a device being formed on the wafer. The method also includes binning the defects with the decision tree.
    Type: Application
    Filed: December 22, 2016
    Publication date: April 13, 2017
    Inventors: Satya Kurada, Raghav Babulnath, Kwok Ng, Lisheng Gao
  • Patent number: 9563943
    Abstract: Methods and systems for design based sampling and binning for yield critical defects are provided. One method includes aligning each image patch in each inspection image frame generated for a wafer by an optical subsystem of an inspection system to design information for the wafer. The method also includes deriving multiple layer design attributes at locations of defects detected in the image patches. In addition, the method includes building a decision tree with the multiple layer design attributes. The decision tree is used to separate the defects into bins with different yield impacts on a device being formed on the wafer. The method also includes binning the defects with the decision tree.
    Type: Grant
    Filed: April 6, 2016
    Date of Patent: February 7, 2017
    Assignee: KLA-Tencor Corp.
    Inventors: Satya Kurada, Raghav Babulnath, Kwok Ng, Lisheng Gao
  • Publication number: 20160275672
    Abstract: Methods and systems for determining a position of output generated by an inspection subsystem in design data space are provided. In general, some embodiments described herein are configured for substantially accurately aligning inspection subsystem output generated for a specimen to a design for the specimen despite deformation of the design in the inspection subsystem output. In addition, some embodiments are configured for generating and/or using alignment targets that can be shared across multiple specimens of the same layer and design rule for alignment of inspection subsystem output generated for a specimen to a design for the specimen.
    Type: Application
    Filed: March 17, 2016
    Publication date: September 22, 2016
    Inventors: Santosh Bhattacharyya, Pavan Kumar, Lisheng Gao, Thirupurasundari Jayaraman, Raghav Babulnath, Srikanth Kandukuri, Gangadharan Sivaraman, Karthikeyan Subramanian, Raghavan Konuru, Rahul Lakhawat
  • Publication number: 20160258879
    Abstract: Methods and systems for generating inspection results for a specimen with an adaptive nuisance filter are provided. One method includes selecting a portion of events detected during inspection of a specimen having values for at least one feature of the events that are closer to at least one value of at least one parameter of the nuisance filter than the values for at least one feature of another portion of the events. The method also includes acquiring output of an output acquisition subsystem for the sample of events, classifying the events in the sample based on the acquired output, and determining if one or more parameters of the nuisance filter should be modified based on results of the classifying. The nuisance filter or the modified nuisance filter can then be applied to results of the inspection of the specimen to generate final inspection results for the specimen.
    Type: Application
    Filed: March 1, 2016
    Publication date: September 8, 2016
    Inventors: Ardis Liang, Martin Plihal, Raghav Babulnath, Sankar Venkataraman
  • Publication number: 20160225138
    Abstract: Methods and systems for design based sampling and binning for yield critical defects are provided. One method includes aligning each image patch in each inspection image frame generated for a wafer by an optical subsystem of an inspection system to design information for the wafer. The method also includes deriving multiple layer design attributes at locations of defects detected in the image patches. In addition, the method includes building a decision tree with the multiple layer design attributes. The decision tree is used to separate the defects into bins with different yield impacts on a device being formed on the wafer. The method also includes binning the defects with the decision tree.
    Type: Application
    Filed: April 6, 2016
    Publication date: August 4, 2016
    Inventors: Satya Kurada, Raghav Babulnath, Kwok Ng, Lisheng Gao
  • Patent number: 9310320
    Abstract: Methods and systems for design based sampling and binning for yield critical defects are provided. One method includes aligning each image patch in each inspection image frame generated for a wafer by an optical subsystem of an inspection system to design information for the wafer. The method also includes deriving multiple layer design attributes at locations of defects detected in the image patches. In addition, the method includes building a decision tree with the multiple layer design attributes. The decision tree is used to separate the defects into bins with different yield impacts on a device being formed on the wafer. The method also includes binning the defects with the decision tree.
    Type: Grant
    Filed: April 11, 2014
    Date of Patent: April 12, 2016
    Assignee: KLA-Tencor Corp.
    Inventors: Satya Kurada, Raghav Babulnath, Kwok Ng, Lisheng Gao
  • Publication number: 20160061745
    Abstract: Systems and methods for detecting defects on a wafer are provided. One method includes generating test image(s) for at least a portion of an array region in die(s) on a wafer from frame image(s) generated by scanning the wafer with an inspection system. The method also includes generating a reference image for cell(s) in the array region from frame images generated by the scanning of the wafer. In addition, the method includes determining difference image(s) for at least one cell in the at least the portion of the array region in the die(s) by subtracting the reference image from portion(s) of the test image(s) corresponding to the at least one cell. The method further includes detecting defects on the wafer in the at least one cell based on the difference image(s).
    Type: Application
    Filed: August 27, 2015
    Publication date: March 3, 2016
    Inventors: Hong Chen, Kenong Wu, Eugene Shifrin, Masatoshi Yamaoka, Gangadharan Sivaraman, Raghav Babulnath, Satya Kurada, Shuo Sun
  • Publication number: 20160033420
    Abstract: Various embodiments for detecting defects on a wafer are provided. One method includes acquiring output generated by an inspection system for a wafer during an inspection process that is performed after at least first and second process steps have been performed on the wafer. The first and second process steps include forming first and second portions, respectively, of a design on the wafer. The first and second portions of the design are mutually exclusive in space on the wafer. The method also includes detecting defects on the wafer based on the output and determining positions of the defects with respect to the first and second portions of the design. In addition, the method includes associating different portions of the defects with the first or second process step based on the positions of the defects with respect to the first and second portions of the design.
    Type: Application
    Filed: July 27, 2015
    Publication date: February 4, 2016
    Inventors: Oksen Toros Baris, Raghav Babulnath
  • Publication number: 20150221076
    Abstract: Systems and methods for classifying defects detected on a wafer are provided. One method includes detecting defects on a wafer based on output generated for the wafer by an inspection system. The method also includes determining one or more attributes for at least one of the defects based on portions of a standard reference image corresponding to the at least one of the defects. The method further includes classifying the at least one of the defects based at least in part on the one or more determined attributes.
    Type: Application
    Filed: February 2, 2015
    Publication date: August 6, 2015
    Inventors: Lisheng Gao, Avijit K. Ray-Chaudhuri, Raghav Babulnath, Kenong Wu
  • Publication number: 20150120220
    Abstract: Methods and systems for detecting reliability defects on a wafer are provided. One method includes acquiring output for a wafer generated by an inspection system. The method also includes determining one or more geometric characteristics of one or more patterned features formed on the wafer based on the output. In addition, the method includes identifying which of the one or more patterned features will cause one or more reliability defects in a device being formed on the wafer based on the determined one or more characteristics.
    Type: Application
    Filed: October 12, 2014
    Publication date: April 30, 2015
    Inventors: Joanne Wu, Ellis Chang, Lisheng Gao, Satya Kurada, Allen Park, Raghav Babulnath
  • Publication number: 20140307947
    Abstract: Methods and systems for design based sampling and binning for yield critical defects are provided. One method includes aligning each image patch in each inspection image frame generated for a wafer by an optical subsystem of an inspection system to design information for the wafer. The method also includes deriving multiple layer design attributes at locations of defects detected in the image patches. In addition, the method includes building a decision tree with the multiple layer design attributes. The decision tree is used to separate the defects into bins with different yield impacts on a device being formed on the wafer. The method also includes binning the defects with the decision tree.
    Type: Application
    Filed: April 11, 2014
    Publication date: October 16, 2014
    Applicant: KLA-Tencor Corporation
    Inventors: Satya Kurada, Raghav Babulnath, Kwok Ng, Lisheng Gao
  • Publication number: 20140303921
    Abstract: Methods and systems for dynamic design attributes for wafer inspection are provided. One method includes, at run time of a wafer inspection recipe, prompting a user of a wafer inspection tool on which the wafer inspection recipe is performed for information for a design based binning (DBB) process. The information includes one or more formulae for calculating design attributes from a design for a wafer. The design attributes are used to bin the defects in the DBB process. The method also includes performing inspection of a wafer according to an updated wafer inspection recipe. Performing the inspection includes binning defects detected on the wafer according to the DBB process in the updated wafer inspection recipe.
    Type: Application
    Filed: April 3, 2014
    Publication date: October 9, 2014
    Applicant: KLA-Tencor Corporation
    Inventors: Thirupurasundari Jayaraman, Raghav Babulnath