Patents by Inventor Mohan Mahadevan
Mohan Mahadevan 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).
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Publication number: 20150370175Abstract: Disclosed are methods and apparatus for inspecting and processing semiconductor wafers. The system includes an edge detection system for receiving each wafer that is to undergo a photolithography process. The edge detection system comprises an illumination channel for directing one or more illumination beams towards a side, top, and bottom edge portion that are within a border region of the wafer. The edge detection system also includes a collection module for collecting and sensing output radiation that is scattered or reflected from the edge portion of the wafer and an analyzer module for locating defects in the edge portion and determining whether each wafer is within specification based on the sensed output radiation for such wafer. The photolithography system is configured for receiving from the edge detection system each wafer that has been found to be within specification. The edge detection system is coupled in-line with the photolithography system.Type: ApplicationFiled: June 17, 2015Publication date: December 24, 2015Applicant: KLA-Tencor CorporationInventors: Lena Nicolaides, Ben-ming Benjamin Tsai, Prashant A. Aji, Michael Gasvoda, Stanley E. Stokowski, Guoheng Zhao, Youxian Wen, Mohan Mahadevan, Paul D. Horn, Wolfgang Vollrath, Isabella T. Lewis
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Publication number: 20150371910Abstract: Photoreflectance spectroscopy is used to measure strain at or near the edge of a wafer in a production process. The strain measurement is used to anticipate defects and make prospective corrections in later stages of the production process. Strain measurements are used to associate various production steps with defects to enhance later production processes.Type: ApplicationFiled: April 16, 2015Publication date: December 24, 2015Inventors: Timothy Goodwin, Lena Nicolaides, Mohan Mahadevan, Paul Horn, Shifang Li
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Publication number: 20150243018Abstract: Shadow-grams are used for edge inspection and metrology of a stacked wafer. The system includes a light source that directs collimated light at an edge of the stacked wafer, a detector opposite the light source, and a controller connected to the detector. The stacked wafer can rotate with respect to the light source. The controller analyzes a shadow-gram image of the edge of the stacked wafer. Measurements of a silhouette of the stacked wafer in the shadow-gram image are compared to predetermined measurements. Multiple shadow-gram images at different points along the edge of the stacked wafer can be aggregated and analyzed.Type: ApplicationFiled: February 24, 2015Publication date: August 27, 2015Inventors: Himanshu VAJARIA, Sina JAHANBIN, Bradley RIES, Mohan MAHADEVAN
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Publication number: 20150234379Abstract: Methods and systems for monitoring process tool conditions are disclosed. The method combines single wafer, multiple wafers within a single lot and multiple lot information together statistically as input to a custom classification engine that can consume single or multiple scan, channel, wafer and lot to determine process tool status.Type: ApplicationFiled: March 13, 2014Publication date: August 20, 2015Applicant: KLA-Tencor CorporationInventors: Himanshu Vajaria, Tommaso Torelli, Bradley Ries, Mohan Mahadevan
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Publication number: 20150226676Abstract: Disclosed are methods and apparatus for detecting defects or reviewing defects in a semiconductor sample. The system has a brightfield (BF) module for directing a BF illumination beam onto a sample and detecting an output beam reflected from the sample in response to the BF illumination beam. The system has a modulated optical reflectance (MOR) module for directing a pump and probe beam to the sample and detecting a MOR output beam from the probe spot in response to the pump beam and the probe beam. The system includes a processor for analyzing the BF output beam from a plurality of BF spots to detect defects on a surface or near the surface of the sample and analyzing the MOR output beam from a plurality of probe spots to detect defects that are below the surface of the sample.Type: ApplicationFiled: February 10, 2015Publication date: August 13, 2015Applicant: KLA-Tencor CorporationInventors: Lena Nicolaides, Mohan Mahadevan, Alex Salnik, Scott A. Young
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Patent number: 9053390Abstract: Methods and systems for determining inspection scenarios without input from a user are presented. Inspection scenarios include at least one acquisition mode, defect detection parameter values, and classification parameter values. In one example, a number of defect events are determined by a hot inspection of a wafer surface. The defect events are classified and attributes associated with each defect event are identified. The defect events are labeled with this information. Based on the identified attributes and classification, inspection scenarios are determined. The inspection scenarios are solutions in a mathematical space formed by the identified attributes. In some examples, a plurality of inspection scenarios are determined and a desired inspection scenario is selected from the plurality based on the number of defects of interest and the number of nuisance events captured by the selected inspection scenario.Type: GrantFiled: August 14, 2012Date of Patent: June 9, 2015Assignee: KLA-Tencor CorporationInventors: Mohan Mahadevan, Govind Thattaisundaram, Ajay Gupta, Chien-Huei (Adam) Chen, Jason Kirkwood, Ashok Kulkarni, Songnian Rong, Ernesto Escorcia, Eugene Shifrin
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Publication number: 20140050389Abstract: Methods and systems for determining inspection scenarios without input from a user are presented. Inspection scenarios include at least one acquisition mode, defect detection parameter values, and classification parameter values. In one example, a number of defect events are determined by a hot inspection of a wafer surface. The defect events are classified and attributes associated with each defect event are identified. The defect events are labeled with this information. Based on the identified attributes and classification, inspection scenarios are determined. The inspection scenarios are solutions in a mathematical space formed by the identified attributes. In some examples, a plurality of inspection scenarios are determined and a desired inspection scenario is selected from the plurality based on the number of defects of interest and the number of nuisance events captured by the selected inspection scenario.Type: ApplicationFiled: August 14, 2012Publication date: February 20, 2014Applicant: KLA-Tencor CorporationInventors: Mohan Mahadevan, Govind Thattaisundaram, Ajay Gupta, Chien-Huei (Adam) Chen, Jason Kirkwood, Ashok Kulkarni, Songnian Rong, Ernesto Escorcia, Eugene Shifrin
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Publication number: 20130250287Abstract: Systems and methods for detecting defects on a wafer are provided. One method includes generating output for a wafer by scanning the wafer with an inspection system using first and second optical states of the inspection system. The first and second optical states are defined by different values for at least one optical parameter of the inspection system. The method also includes generating first image data for the wafer using the output generated using the first optical state and second image data for the wafer using the output generated using the second optical state. In addition, the method includes combining the first image data and the second image data corresponding to substantially the same locations on the wafer thereby creating additional image data for the wafer. The method further includes detecting defects on the wafer using the additional image data.Type: ApplicationFiled: May 22, 2013Publication date: September 26, 2013Applicant: KLA-Tencor CorporationInventors: Lu Chen, Jason Kirkwood, Mohan Mahadevan, James A. Smith, Lisheng Gao, Junqing (Jenny) Huang, Tao Luo, Richard Wallingford
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Patent number: 8467047Abstract: Systems and methods for detecting defects on a wafer are provided. One method includes generating output for a wafer by scanning the wafer with an inspection system using first and second optical states of the inspection system. The first and second optical states are defined by different values for at least one optical parameter of the inspection system. The method also includes generating first image data for the wafer using the output generated using the first optical state and second image data for the wafer using the output generated using the second optical state. In addition, the method includes combining the first image data and the second image data corresponding to substantially the same locations on the wafer thereby creating additional image data for the wafer. The method further includes detecting defects on the wafer using the additional image data.Type: GrantFiled: July 3, 2012Date of Patent: June 18, 2013Assignee: KLA-Tencor Corp.Inventors: Lu Chen, Jason Kirkwood, Mohan Mahadevan, James A. Smith, Lisheng Gao, Junqing (Jenny) Huang, Tao Luo, Richard Wallingford
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Publication number: 20120268735Abstract: Systems and methods for detecting defects on a wafer are provided. One method includes generating output for a wafer by scanning the wafer with an inspection system using first and second optical states of the inspection system. The first and second optical states are defined by different values for at least one optical parameter of the inspection system. The method also includes generating first image data for the wafer using the output generated using the first optical state and second image data for the wafer using the output generated using the second optical state. In addition, the method includes combining the first image data and the second image data corresponding to substantially the same locations on the wafer thereby creating additional image data for the wafer. The method further includes detecting defects on the wafer using the additional image data.Type: ApplicationFiled: July 3, 2012Publication date: October 25, 2012Applicant: KLA-TENCOR CORPORATIONInventors: Lu Chen, Jason Kirkwood, Mohan Mahadevan, James A. Smith, Lisheng Gao, Junqing (Jenny) Huang, Tao Luo, Richard Wallingford
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Patent number: 8223327Abstract: Systems and methods for detecting defects on a wafer are provided. One method includes generating output for a wafer by scanning the wafer with an inspection system using first and second optical states of the inspection system. The first and second optical states are defined by different values for at least one optical parameter of the inspection system. The method also includes generating first image data for the wafer using the output generated using the first optical state and second image data for the wafer using the output generated using the second optical state. In addition, the method includes combining the first image data and the second image data corresponding to substantially the same locations on the wafer thereby creating additional image data for the wafer. The method further includes detecting defects on the wafer using the additional image data.Type: GrantFiled: January 26, 2009Date of Patent: July 17, 2012Assignee: KLA-Tencor Corp.Inventors: Lu Chen, Jason Kirkwood, Mohan Mahadevan, James A. Smith, Lisheng Gao, Junqing (Jenny) Huang, Tao Luo, Richard Wallingford
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Publication number: 20120116733Abstract: Various embodiments for determining parameters for wafer inspection and/or metrology are provided.Type: ApplicationFiled: June 9, 2011Publication date: May 10, 2012Applicant: KLA-TENCOR CORPORATIONInventors: Govind Thattaisundaram, Mohan Mahadevan, Ajay Gupta, Chien-Huei Adam Chen, Ashok Kulkarni, Jason Kirkwood, Kenong Wu, Songnian Rong
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Patent number: 8126255Abstract: Various systems and methods for creating persistent data for a wafer and using persistent data for inspection-related functions are provided. One system includes a set of processor nodes coupled to a detector of an inspection system. Each of the processor nodes is configured to receive a portion of image data generated by the detector during scanning of a wafer. The system also includes an array of storage media separately coupled to each of the processor nodes. The processor nodes are configured to send all of the image data or a selected portion of the image data received by the processor nodes to the arrays of storage media such that all of the image data or the selected portion of the image data generated by the detector during the scanning of the wafer is stored in the arrays of the storage media.Type: GrantFiled: September 19, 2008Date of Patent: February 28, 2012Assignee: KLA-Tencor Corp.Inventors: Kris Bhaskar, Chetana Bhaskar, Ashok Kulkarni, Eliezer Rosengaus, Cecelia Campochiaro, Chris Maher, Brian Duffy, Aneesh Khullar, Alpa Kohli, Lalita A. Balasubramanian, Santosh Bhattacharyya, Mohan Mahadevan
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Publication number: 20100188657Abstract: Systems and methods for detecting defects on a wafer are provided. One method includes generating output for a wafer by scanning the wafer with an inspection system using first and second optical states of the inspection system. The first and second optical states are defined by different values for at least one optical parameter of the inspection system. The method also includes generating first image data for the wafer using the output generated using the first optical state and second image data for the wafer using the output generated using the second optical state. In addition, the method includes combining the first image data and the second image data corresponding to substantially the same locations on the wafer thereby creating additional image data for the wafer. The method further includes detecting defects on the wafer using the additional image data.Type: ApplicationFiled: January 26, 2009Publication date: July 29, 2010Applicant: KLA-TENCOR CORPORATIONInventors: Lu Chen, Jason Kirkwood, Mohan Mahadevan, James A. Smith, Lisheng Gao, Junqing (Jenny) Huang, Tao Luo, Richard Wallingford
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Publication number: 20090080759Abstract: Various systems and methods for creating persistent data for a wafer and using persistent data for inspection-related functions are provided. One system includes a set of processor nodes coupled to a detector of an inspection system. Each of the processor nodes is configured to receive a portion of image data generated by the detector during scanning of a wafer. The system also includes an array of storage media separately coupled to each of the processor nodes. The processor nodes are configured to send all of the image data or a selected portion of the image data received by the processor nodes to the arrays of storage media such that all of the image data or the selected portion of the image data generated by the detector during the scanning of the wafer is stored in the arrays of the storage media.Type: ApplicationFiled: September 19, 2008Publication date: March 26, 2009Applicant: KLA-TENCOR CORPORATIONInventors: Kris Bhaskar, Chetana Bhaskar, Ashok Kulkarni, Eliezer Rosengaus, Cecilia Campochiaro, Chris Maher, Brian Duffy, Aneesh Khullar, Alpa Kohli, Lalita A. Balasubramanian, Santosh Bhattacharyya, Mohan Mahadevan