Patents by Inventor Nagasubramaniyan Chandrasekaran
Nagasubramaniyan Chandrasekaran 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: 20070010170Abstract: Monitoring the process of planarizing a workpiece, e.g., conditioning a CMP pad, can present some difficulties. Aspects of this invention provide methods and systems for monitoring and/or controlling such a planarization cycle. For example, a control system may monitor the proximity of a workpiece holder and an abrasion member by measuring the capacitance between a first sensor associated with the workpiece holder and a second sensor associated with the abrasion member. This exemplary control system may adjust a process parameter of the planarization cycle in response to a change in the measured capacitance. This can be useful in endpointing the planarization cycle, for example. In certain applications, the control system may define a pad profile based on multiple capacitance measurements and use the pad profile to achieve better planarity of the planarized surface.Type: ApplicationFiled: June 29, 2006Publication date: January 11, 2007Applicant: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Patent number: 7147543Abstract: Carrier assemblies, planarizing machines with carrier assemblies, and methods for mechanical and/or chemical-mechanical planarization of micro-device workpieces are disclosed herein. In one embodiment, the carrier assembly includes a head having a chamber, a magnetic field source carried by the head, and a fluid with magnetic elements in the chamber. The magnetic field source has a first member that induces a magnetic field in the head. The fluid and/or the magnetic elements move within the chamber under the influence of the magnetic field source to exert a force against a portion of the micro-device workpiece. In a further aspect of this embodiment, the carrier assembly includes a flexible member in the chamber. The magnetic field source can be any device that induces a magnetic field, such as a permanent magnet, an electromagnet, or an electrically conductive coil.Type: GrantFiled: July 28, 2005Date of Patent: December 12, 2006Assignee: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Publication number: 20060228995Abstract: Systems and methods for monitoring characteristics of a polishing pad used in polishing a micro-device workpiece are disclosed herein. In one embodiment, a method for monitoring a characteristic of a polishing pad includes applying ultrasonic energy to the polishing pad and determining a status of the characteristic based on a measurement of the ultrasonic energy applied to the polishing pad. In one aspect of this embodiment, applying ultrasonic energy includes applying ultrasonic energy from a transducer. The transducer can be carried by a conditioner, a fluid arm, a micro-device workpiece carrier, or a table. In another aspect of this embodiment, determining the status of the characteristic includes determining a thickness, density, surface contour, roughness, or texture of the polishing pad.Type: ApplicationFiled: June 7, 2006Publication date: October 12, 2006Applicant: Micron Technology, Inc.Inventors: Jason Elledge, Nagasubramaniyan Chandrasekaran
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Patent number: 7115016Abstract: Planarizing machines and methods for mechanical and/or chemical-mechanical planarization of micro-device workpieces are disclosed herein. In one embodiment, a method for polishing a workpiece includes determining an estimated frequency of serial defects in a workpiece, pressing the workpiece against a polishing pad and moving the workpiece relative to the pad. The method further includes vibrating the workpiece and/or the pad at a frequency that is greater than the estimated frequency of the serial defects. In one aspect of this embodiment, determining the estimated frequency of serial defects can include: determining a relative velocity between the workpiece and the polishing pad; estimating the length of a mark on the workpiece; estimating the time a particle in a planarizing solution is in contact with the workpiece; and estimating the number of cracks in the workpiece.Type: GrantFiled: December 1, 2005Date of Patent: October 3, 2006Assignee: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Publication number: 20060194515Abstract: Monitoring the process of planarizing a workpiece, e.g., conditioning a CMP pad, can present some difficulties. Aspects of this invention provide methods and systems for monitoring and/or controlling such a planarization cycle. For example, a control system may monitor the proximity of a workpiece holder and an abrasion member by measuring the capacitance between a first sensor associated with the workpiece holder and a second sensor associated with the abrasion member. This exemplary control system may adjust a process parameter of the planarization cycle in response to a change in the measured capacitance. This can be useful in endpointing the planarization cycle, for example. In certain applications, the control system may define a pad profile based on multiple capacitance measurements and use the pad profile to achieve better planarity of the planarized surface.Type: ApplicationFiled: February 8, 2006Publication date: August 31, 2006Applicant: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Patent number: 7070478Abstract: Systems and methods for monitoring characteristics of a polishing pad used in polishing a micro-device workpiece are disclosed herein. In one embodiment, a method for monitoring a characteristic of a polishing pad includes applying ultrasonic energy to the polishing pad and determining a status of the characteristic based on a measurement of the ultrasonic energy applied to the polishing pad. In one aspect of this embodiment, applying ultrasonic energy includes applying ultrasonic energy from a transducer. The transducer can be carried by a conditioner, a fluid arm, a micro-device workpiece carrier, or a table. In another aspect of this embodiment, determining the status of the characteristic includes determining a thickness, density, surface contour, roughness, or texture of the polishing pad.Type: GrantFiled: August 31, 2004Date of Patent: July 4, 2006Assignee: Micron Technology, Inc.Inventors: Jason B. Elledge, Nagasubramaniyan Chandrasekaran
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Publication number: 20060128273Abstract: Monitoring the process of planarizing a workpiece, e.g., conditioning a CMP pad, can present some difficulties. Aspects of this invention provide methods and systems for monitoring and/or controlling such a planarization cycle. For example, a control system may monitor the proximity of a workpiece holder and an abrasion member by measuring the capacitance between a first sensor associated with the workpiece holder and a second sensor associated with the abrasion member. This exemplary control system may adjust a process parameter of the planarization cycle in response to a change in the measured capacitance. This can be useful in endpointing the planarization cycle, for example. In certain applications, the control system may define a pad profile based on multiple capacitance measurements and use the pad profile to achieve better planarity of the planarized surface.Type: ApplicationFiled: February 8, 2006Publication date: June 15, 2006Applicant: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Patent number: 7033246Abstract: Systems and methods for monitoring characteristics of a polishing pad used in polishing a micro-device workpiece are disclosed herein. In one embodiment, a method for monitoring a characteristic of a polishing pad includes applying ultrasonic energy to the polishing pad and determining a status of the characteristic based on a measurement of the ultrasonic energy applied to the polishing pad. In one aspect of this embodiment, applying ultrasonic energy includes applying ultrasonic energy from a transducer. The transducer can be carried by a conditioner, a fluid arm, a micro-device workpiece carrier, or a table. In another aspect of this embodiment, determining the status of the characteristic includes determining a thickness, density, surface contour, roughness, or texture of the polishing pad.Type: GrantFiled: August 31, 2004Date of Patent: April 25, 2006Assignee: Micron Technology, Inc.Inventors: Jason B. Elledge, Nagasubramaniyan Chandrasekaran
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Patent number: 7033248Abstract: Systems and methods for monitoring characteristics of a polishing pad used in polishing a micro-device workpiece are disclosed herein. In one embodiment, a method for monitoring a characteristic of a polishing pad includes applying ultrasonic energy to the polishing pad and determining a status of the characteristic based on a measurement of the ultrasonic energy applied to the polishing pad. In one aspect of this embodiment, applying ultrasonic energy includes applying ultrasonic energy from a transducer. The transducer can be carried by a conditioner, a fluid arm, a micro-device workpiece carrier, or a table. In another aspect of this embodiment, determining the status of the characteristic includes determining a thickness, density, surface contour, roughness, or texture of the polishing pad.Type: GrantFiled: August 31, 2004Date of Patent: April 25, 2006Assignee: Micron Technology, Inc.Inventors: Jason B. Elledge, Nagasubramaniyan Chandrasekaran
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Publication number: 20060073767Abstract: Planarizing machines and methods for mechanical and/or chemical-mechanical planarization of micro-device workpieces are disclosed herein. In one embodiment, a method for polishing a workpiece includes determining an estimated frequency of serial defects in a workpiece, pressing the workpiece against a polishing pad and moving the workpiece relative to the pad. The method further includes vibrating the workpiece and/or the pad at a frequency that is greater than the estimated frequency of the serial defects. In one aspect of this embodiment, determining the estimated frequency of serial defects can include: determining a relative velocity between the workpiece and the polishing pad; estimating the length of a mark on the workpiece; estimating the time a particle in a planarizing solution is in contact with the workpiece; and estimating the number of cracks in the workpiece.Type: ApplicationFiled: December 1, 2005Publication date: April 6, 2006Applicant: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Patent number: 7011566Abstract: Monitoring the process of planarizing a workpiece, e.g., conditioning a CMP pad, can present some difficulties. Aspects of this invention provide methods and systems for monitoring and/or controlling such a planarization cycle. For example, a control system may monitor the proximity of a workpiece holder and an abrasion member by measuring the capacitance between a first sensor associated with the workpiece holder and a second sensor associated with the abrasion member. This exemplary control system may adjust a process parameter of the planarization cycle in response to a change in the measured capacitance. This can be useful in endpointing the planarization cycle, for example. In certain applications, the control system may define a pad profile based on multiple capacitance measurements and use the pad profile to achieve better planarity of the planarized surface.Type: GrantFiled: August 26, 2002Date of Patent: March 14, 2006Assignee: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Patent number: 7008299Abstract: Planarizing machines and methods for mechanical and/or chemical-mechanical planarization of micro-device workpieces are disclosed herein. In one embodiment, a method for polishing a workpiece includes determining an estimated frequency of serial defects in a workpiece, pressing the workpiece against a polishing pad and moving the workpiece relative to the pad. The method further includes vibrating the workpiece and/or the pad at a frequency that is greater than the estimated frequency of the serial defects. In one aspect of this embodiment, determining the estimated frequency of serial defects can include: determining a relative velocity between the workpiece and the polishing pad; estimating the length of a mark on the workpiece; estimating the time a particle in a planarizing solution is in contact with the workpiece; and estimating the number of cracks in the workpiece.Type: GrantFiled: August 29, 2002Date of Patent: March 7, 2006Assignee: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Patent number: 7004817Abstract: Carrier assemblies, planarizing machines with carrier assemblies, and methods for mechanical and/or chemical-mechanical planarization of micro-device workpieces are disclosed herein. In one embodiment, the carrier assembly includes a head having a chamber, a magnetic field source carried by the head, and a fluid with magnetic elements in the chamber. The magnetic field source has a first member that induces a magnetic field in the head. The fluid and/or the magnetic elements move within the chamber under the influence of the magnetic field source to exert a force against a portion of the micro-device workpiece. In a further aspect of this embodiment, the carrier assembly includes a flexible member in the chamber. The magnetic field source can be any device that induces a magnetic field, such as a permanent magnet, an electromagnet, or an electrically conductive coil.Type: GrantFiled: August 23, 2002Date of Patent: February 28, 2006Assignee: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Publication number: 20050260927Abstract: Carrier assemblies, planarizing machines with carrier assemblies, and methods for mechanical and/or chemical-mechanical planarization of micro-device workpieces are disclosed herein. In one embodiment, the carrier assembly includes a head having a chamber, a magnetic field source carried by the head, and a fluid with magnetic elements in the chamber. The magnetic field source has a first member that induces a magnetic field in the head. The fluid and/or the magnetic elements move within the chamber under the influence of the magnetic field source to exert a force against a portion of the micro-device workpiece. In a further aspect of this embodiment, the carrier assembly includes a flexible member in the chamber. The magnetic field source can be any device that induces a magnetic field, such as a permanent magnet, an electromagnet, or an electrically conductive coil.Type: ApplicationFiled: July 28, 2005Publication date: November 24, 2005Applicant: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Publication number: 20050239382Abstract: A planarizing slurry for mechanical and/or chemical-mechanical polishing of microfeature workpieces. In one embodiment, the planarizing slurry comprises a liquid solution and a plurality of abrasive elements mixed in the liquid solution. The abrasive elements comprise a matrix material having a first hardness and a plurality of abrasive particles at least partially surrounded by the matrix material. The abrasive particles can have a second hardness independent of the first hardness of the matrix material. The second hardness, for example, can be greater than the first hardness. The matrix material can be formed into a core having an exterior surface and an interior. Because the abrasive particles are at least partially surrounded by the matrix material, the abrasive particles are at least partially embedded into the interior of the core.Type: ApplicationFiled: June 28, 2005Publication date: October 27, 2005Applicant: Micron Technology, Inc.Inventors: Theodore Taylor, Nagasubramaniyan Chandrasekaran
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Patent number: 6958001Abstract: Carrier assemblies, planarizing machines with carrier assemblies, and methods for mechanical and/or chemical-mechanical planarization of micro-device workpieces are disclosed herein. In one embodiment, the carrier assembly includes a head having a chamber, a magnetic field source carried by the head, and a fluid with magnetic elements in the chamber. The magnetic field source has a first member that induces a magnetic field in the head. The fluid and/or the magnetic elements move within the chamber under the influence of the magnetic field source to exert a force against a portion of the micro-device workpiece. In a further aspect of this embodiment, the carrier assembly includes a flexible member in the chamber. The magnetic field source can be any device that induces a magnetic field, such as a permanent magnet, an electromagnet, or an electrically conductive coil.Type: GrantFiled: December 13, 2004Date of Patent: October 25, 2005Assignee: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Publication number: 20050205523Abstract: Microelectronic devices including a layer of germanium and selenium, optionally including up to 10 atomic percent silver, show promise for select applications. Manufacturing microelectronic devices containing such layers using conventional CMP processes presents some significant challenges. Embodiments of the invention provide methods of planarizing workpieces with Ge—Se layers, many of which can be carried out using conventional CMP equipment. Other embodiments of the invention provide chemical-mechanical polishing systems adapted to produce planarized workpieces with Ge—Se layers or, in at least one embodiment, other alternative layers. Various approaches suggested herein facilitate production of such microelectronic devices by appropriate control of the down force of the Ge—Se layer against the planarizing medium and/or one or more aspects of the planarizing medium, which aspects include pH, abrasive particle size, abrasive particle hardness, weight percent of abrasive.Type: ApplicationFiled: April 21, 2005Publication date: September 22, 2005Applicant: Micron Technology, Inc.Inventors: Nagasubramaniyan Chandrasekaran, Theodore Taylor
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Patent number: 6939211Abstract: A planarizing slurry for mechanical and/or chemical-mechanical polishing of microfeature workpieces. In one embodiment, the planarizing slurry comprises a liquid solution and a plurality of abrasive elements mixed in the liquid solution. The abrasive elements comprise a matrix material having a first hardness and a plurality of abrasive particles at least partially surrounded by the matrix material. The abrasive particles can have a second hardness independent of the first hardness of the matrix material. The second hardness, for example, can be greater than the first hardness. The matrix material can be formed into a core having an exterior surface and an interior. Because the abrasive particles are at least partially surrounded by the matrix material, the abrasive particles are at least partially embedded into the interior of the core.Type: GrantFiled: October 9, 2003Date of Patent: September 6, 2005Assignee: Micron Technology, Inc.Inventors: Theodore M. Taylor, Nagasubramaniyan Chandrasekaran
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Publication number: 20050118930Abstract: Carrier assemblies, planarizing machines with carrier assemblies, and methods for mechanical and/or chemical-mechanical planarization of micro-device workpieces are disclosed herein. In one embodiment, the carrier assembly includes a head having a chamber, a magnetic field source carried by the head, and a fluid with magnetic elements in the chamber. The magnetic field source has a first member that induces a magnetic field in the head. The fluid and/or the magnetic elements move within the chamber under the influence of the magnetic field source to exert a force against a portion of the micro-device workpiece. In a further aspect of this embodiment, the carrier assembly includes a flexible member in the chamber. The magnetic field source can be any device that induces a magnetic field, such as a permanent magnet, an electromagnet, or an electrically conductive coil.Type: ApplicationFiled: December 13, 2004Publication date: June 2, 2005Inventor: Nagasubramaniyan Chandrasekaran
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Patent number: 6884144Abstract: Microelectronic devices including a layer of germanium and selenium, optionally including up to 10 atomic percent silver, show promise for select applications. Manufacturing microelectronic devices containing such layers using conventional CMP processes presents some significant challenges. Embodiments of the invention provide methods of planarizing workpieces with Ge—Se layers, many of which can be carried out using conventional CMP equipment. Other embodiments of the invention provide chemical-mechanical polishing systems adapted to produce planarized workpieces with Ge—Se layers or, in at least one embodiment, other alternative layers. Various approaches suggested herein facilitate production of such microelectronic devices by appropriate control of the down force of the Ge—Se layer against the planarizing medium and/or one or more aspects of the planarizing medium, which aspects include pH, abrasive particle size, abrasive particle hardness, weight percent of abrasive.Type: GrantFiled: August 16, 2002Date of Patent: April 26, 2005Assignee: Micron Technology, Inc.Inventors: Nagasubramaniyan Chandrasekaran, Theodore M. Taylor