Patents by Inventor Sanjay Yedur
Sanjay Yedur 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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Patent number: 7702471Abstract: Provided is a method of determining one or more profile parameters of a photomask covered with a pellicle, the method comprising developing an optical metrology model of a pellicle covering a photomask, developing an optical metrology model of the photomask, the photomask separated from the pellicle by a medium and having a structure, the structure having profile parameters, the optical metrology model of the photomask taking into account the optical effects on the illumination beam transmitted through the pellicle and diffracted by the photomask structure. The optical metrology model of the pellicle and the optical metrology model of the photomask structure are integrated and optimized. At least one profile parameters of the photomask structure is determined using the optimized integrated optical metrology model.Type: GrantFiled: May 24, 2007Date of Patent: April 20, 2010Assignee: Tokyo Electron LimitedInventors: Shifang Li, Sanjay Yedur
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Patent number: 7639375Abstract: Transmittance of a photomask is determined using optical metrology. In particular, reflectance of a portion of the photomask is determined by directing an incident beam of light at the portion of the photomask. The reflectance is determined by measuring light diffracted from the portion of the photomask. One or more geometric features of the portion of the photomask are determined using the measured light diffracted from the portion of the photomask. A wave coupling is determined using the determined one or more geometric features of the portion of the photomask. The transmittance of the photomask is determined using the determined wave coupling and the determined reflectance of the portion of the photomask.Type: GrantFiled: December 14, 2006Date of Patent: December 29, 2009Assignee: Tokyo Electron LimitedInventors: Sanjay Yedur, Shifang Li, Youxian Wen, Wei Liu, Hanyou Chu, Ying Ying Luo
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Patent number: 7518740Abstract: A profile model to characterize a structure to be examined using optical metrology is evaluated by displaying a set of profile parameters that characterizes the profile model. Each profile parameter has a range of values for the profile parameter. For each profile parameter having a range of values, an adjustment tool is displayed for selecting a value for the profile parameter within the range of values. A measured diffraction signal, which was measured using an optical metrology tool, is displayed. A simulated diffraction signal, which was generated based on the values of the profile parameters selected using the adjustment tools for the profile parameters, is displayed. The simulated diffraction signal is overlaid with the measured diffraction signal.Type: GrantFiled: July 10, 2006Date of Patent: April 14, 2009Assignee: Tokyo Electron LimitedInventors: Jeffrey A. Chard, Junwei Bao, Youxian Wen, Sanjay Yedur
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Patent number: 7480062Abstract: Provided is a method of controlling a photolithography cluster or a subsequent fabrication cluster using optical metrology to determine profile parameters of a photomask structure covered with a pellicle. An optical metrology model of the pellicle is developed and integrated with the optical metrology model of the photomask structure. The optical metrology model of the photomask taking into account the optical effects on the illumination and detection beams transmitted through the pellicle and diffracted by the photomask structure. One or more profile parameters of the photomask structure is determined and used to adjust one or more process parameters or equipment settings of a photolithography cluster using the photomask or a subsequent fabrication cluster.Type: GrantFiled: May 25, 2007Date of Patent: January 20, 2009Assignee: Tokyo Electron LimitedInventors: Shifang Li, Sanjay Yedur, Manuel Madriaga
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Publication number: 20080291467Abstract: Provided is a method of determining one or more profile parameters of a photomask covered with a pellicle, the method comprising developing an optical metrology model of a pellicle covering a photomask, developing an optical metrology model of the photomask, the photomask separated from the pellicle by a medium and having a structure, the structure having profile parameters, the optical metrology model of the photomask taking into account the optical effects on the illumination beam transmitted through the pellicle and diffracted by the photomask structure. The optical metrology model of the pellicle and the optical metrology model of the photomask structure are integrated and optimized. At least one profile parameters of the photomask structure is determined using the optimized integrated optical metrology model.Type: ApplicationFiled: May 24, 2007Publication date: November 27, 2008Applicant: TOKYO ELECTRON LIMITEDInventors: SHIFANG LI, SANJAY YEDUR
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Publication number: 20080291429Abstract: Provided is a method of controlling a photolithography cluster or a subsequent fabrication cluster using optical metrology to determine profile parameters of a photomask structure covered with a pellicle. An optical metrology model of the pellicle is developed and integrated with the optical metrology model of the photomask structure. The optical metrology model of the photomask taking into account the optical effects on the illumination and detection beams transmitted through the pellicle and diffracted by the photomask structure. One or more profile parameters of the photomask structure is determined and used to adjust one or more process parameters or equipment settings of a photolithography cluster using the photomask or a subsequent fabrication cluster.Type: ApplicationFiled: May 25, 2007Publication date: November 27, 2008Applicant: TOKYO ELECTRON LIMITEDInventors: SHIFANG LI, SANJAY YEDUR, MANUEL MADRIAGA
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Patent number: 7394554Abstract: A hypothetical profile is used to model the profile of a structure formed on a semiconductor wafer to use in determining the profile of the structure using optical metrology. To select a hypothetical profile, sample diffraction signals are obtained from measured diffraction signals of structures formed on the wafer, where the sample diffraction signals are a representative sampling of the measured diffraction signals. A hypothetical profile is defined and evaluated using a sample diffraction signal from the obtained sample diffraction signals.Type: GrantFiled: September 15, 2003Date of Patent: July 1, 2008Assignee: Timbre Technologies, Inc.Inventors: Vi Vuong, Junwei Bao, Srinivas Doddi, Emmanuel Drege, Jin Wen, Sanjay Yedur, Doris Chin, Nickhil Jakatdar, Lawrence Lane
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Publication number: 20080144919Abstract: Transmittance of a photomask is determined using optical metrology. In particular, reflectance of a portion of the photomask is determined by directing an incident beam of light at the portion of the photomask. The reflectance is determined by measuring light diffracted from the portion of the photomask. One or more geometric features of the portion of the photomask are determined using the measured light diffracted from the portion of the photomask. A wave coupling is determined using the determined one or more geometric features of the portion of the photomask. The transmittance of the photomask is determined using the determined wave coupling and the determined reflectance of the portion of the photomask.Type: ApplicationFiled: December 14, 2006Publication date: June 19, 2008Applicant: Tokyo Electron LimitedInventors: Sanjay Yedur, Shifang Li, Youxian Wen, Wei Liu, Hanyou Chu, Ying Ying Luo
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Publication number: 20080007738Abstract: A profile model to characterize a structure to be examined using optical metrology is evaluated by displaying a set of profile parameters that characterizes the profile model. Each profile parameter has a range of values for the profile parameter. For each profile parameter having a range of values, an adjustment tool is displayed for selecting a value for the profile parameter within the range of values. A measured diffraction signal, which was measured using an optical metrology tool, is displayed. A simulated diffraction signal, which was generated based on the values of the profile parameters selected using the adjustment tools for the profile parameters, is displayed. The simulated diffraction signal is overlaid with the measured diffraction signal.Type: ApplicationFiled: July 10, 2006Publication date: January 10, 2008Applicant: Tokyo Electron LimitedInventors: Jeffrey A. Chard, Junwei Bao, Youxian Wen, Sanjay Yedur
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Patent number: 7092110Abstract: A profile model for use in optical metrology of structures in a wafer is selected based on a template having one or more parameters including characteristics of process and modeling attributes associated with a structure in a wafer. The process includes performing a profile modeling process to generate a profile model of a wafer structure based on a template having one or more parameters including characteristics of process and modeling attributes. The profile model includes a set of geometric parameters associated with the dimensions of the structure. The generated profile model may further be tested against termination criteria and the one or more parameters modified. The process of performing a modeling process to generate a profile model and testing the generated profile model may be repeated until the termination criteria are met.Type: GrantFiled: March 25, 2003Date of Patent: August 15, 2006Assignee: Timbre Technologies, Inc.Inventors: Raghu Balasubramanian, Sanjay Yedur, Vi Vuong, Nickhil Jakatdar
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Patent number: 7046375Abstract: Edge roughness and deterministic profile of a structure formed on a semiconductor wafer are measured using optical metrology by directing an incident beam on the structure using a source and receiving the diffracted beam from the structure using a detector. The received diffracted beam is processed using a processor to determine a deterministic profile of the structure and to measure an edge roughness of the structure.Type: GrantFiled: May 2, 2003Date of Patent: May 16, 2006Assignee: Timbre Technologies, Inc.Inventors: Joerg Bischoff, Emmanuel Drege, Sanjay Yedur
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Publication number: 20050057748Abstract: A hypothetical profile is used to model the profile of a structure formed on a semiconductor wafer to use in determining the profile of the structure using optical metrology. To select a hypothetical profile, sample diffraction signals are obtained from measured diffraction signals of structures formed on the wafer, where the sample diffraction signals are a representative sampling of the measured diffraction signals. A hypothetical profile is defined and evaluated using a sample diffraction signal from the obtained sample diffraction signals.Type: ApplicationFiled: September 15, 2003Publication date: March 17, 2005Applicant: TimbreTechnologies, Inc.Inventors: Vi Vuong, Junwei Bao, Srini Doddi, Emmanuel Drege, Jin Wen, Sanjay Yedur, Doris Chin, Nickhil Jakatdar, Lawrence Lane
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Publication number: 20040218192Abstract: Edge roughness and deterministic profile of a structure formed on a semiconductor wafer are measured using optical metrology by directing an incident beam on the structure using a source and receiving the diffracted beam from the structure using a detector. The received diffracted beam is processed using a processor to determine a deterministic profile of the structure and to measure an edge roughness of the structure.Type: ApplicationFiled: May 2, 2003Publication date: November 4, 2004Inventors: Joerg Bischoff, Emmanuel Drege, Sanjay Yedur
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Publication number: 20040017575Abstract: A profile model for use in optical metrology of structures in a wafer is selected based on a template having one or more parameters including characteristics of process and modeling attributes associated with a structure in a wafer. The process includes performing a profile modeling process to generate a profile model of a wafer structure based on a template having one or more parameters including characteristics of process and modeling attributes. The profile model includes a set of geometric parameters associated with the dimensions of the structure. The generated profile model may further be tested against termination criteria and the one or more parameters modified. The process of performing a modeling process to generate a profile model and testing the generated profile model may be repeated until the termination criteria are met.Type: ApplicationFiled: March 25, 2003Publication date: January 29, 2004Inventors: Raghu Balasubramanian, Sanjay Yedur, Vi Vuong, Nickhil Jakatdar
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Patent number: 6265190Abstract: A highly efficient process for the production and recovery of pure succinic acid from a succinate salt that involves minimal use of additional reagents, and produces virtually no waste by-products, and permits internal recycle of the base and acid values, is provided. The method involves the formation of diammonium succinate, either by using an ammonium ion based material to maintain neutral8 pH in the fermenter or by substituting the ammonium cation for the cation of the succinate salt created in the fermenter. The diammonium succinate can then be reacted with a sulfate ion, such as by combining the diammonium succinate with ammonium bisulfate and/or sulfuric acid at sufficiently low pH to yield succinic acid and ammonium sulfate. The ammonium sulfate is advantageously cracked thermally into ammonia and ammonium bisulfate. The succinic acid can be purified with a methanol dissolution step. Various filtration, reflux and reutilization steps can also be employed.Type: GrantFiled: September 2, 1999Date of Patent: July 24, 2001Assignees: Michigan State University, Applied CarboChemicals, Inc.Inventors: Sanjay Yedur, Kris A. Berglund, Dilum D. Dunuwila
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Patent number: 6117618Abstract: In one embodiment, the present invention relates to a method of making a carbonized antireflection coating involving the steps of depositing a polymer layer on a semiconductor substrate; and carbonizing at least a portion of the polymer layer in an inert atmosphere to provide the carbonized antireflection coating. In another embodiment, the present invention relates to a method of improving critical dimensional control during lithography, involving the steps of providing a semiconductor substrate; depositing a polymer layer on the semiconductor substrate; carbonizing at least a portion of the polymer layer in an inert atmosphere to provide a carbonized antireflection coating; depositing a photoresist over the carbonized antireflection coating; and patterning the photoresist.Type: GrantFiled: November 4, 1998Date of Patent: September 12, 2000Assignee: Advanced Micro Devices, Inc.Inventors: Sanjay Yedur, Bhanwar Singh, Bharath Rangarajan, Michael Templeton
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Patent number: 5958744Abstract: A highly efficient process for the production and recovery of pure succinic acid from a succinate salt that involves minimal use of additional reagents, and produces virtually no waste by-products, and permits internal recycle of the base and acid values, is provided. The method involves the formation of diammonium succinate, either by using an ammonium ion based material to maintain neutral8 pH in the fermenter or by substituting the ammonium cation for the cation of the succinate salt created in the fermenter. The diammonium succinate can then be reacted with a sulfate ion, such as by combining the diammonium succinate with ammonium bisulfate and/or sulfuric acid at sufficiently low pH to yield succinic acid and ammonium sulfate. The ammonium sulfate is advantageously cracked thermally into ammonia and ammonium bisulfate. The succinic acid can be purified with a methanol dissolution step. Various filtration, reflux and reutilization steps can also be employed.Type: GrantFiled: August 13, 1998Date of Patent: September 28, 1999Assignee: Applied CarbochemicalsInventors: Kris A. Berglund, Sanjay Yedur, Dilum D. Dunuwila