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).

  • Publication number: 20070010170
    Abstract: 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: Application
    Filed: June 29, 2006
    Publication date: January 11, 2007
    Applicant: Micron Technology, Inc.
    Inventor: Nagasubramaniyan Chandrasekaran
  • Patent number: 7147543
    Abstract: 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: Grant
    Filed: July 28, 2005
    Date of Patent: December 12, 2006
    Assignee: Micron Technology, Inc.
    Inventor: Nagasubramaniyan Chandrasekaran
  • Publication number: 20060228995
    Abstract: 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: Application
    Filed: June 7, 2006
    Publication date: October 12, 2006
    Applicant: Micron Technology, Inc.
    Inventors: Jason Elledge, Nagasubramaniyan Chandrasekaran
  • Patent number: 7115016
    Abstract: 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: Grant
    Filed: December 1, 2005
    Date of Patent: October 3, 2006
    Assignee: Micron Technology, Inc.
    Inventor: Nagasubramaniyan Chandrasekaran
  • Publication number: 20060194515
    Abstract: 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: Application
    Filed: February 8, 2006
    Publication date: August 31, 2006
    Applicant: Micron Technology, Inc.
    Inventor: Nagasubramaniyan Chandrasekaran
  • Patent number: 7070478
    Abstract: 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: Grant
    Filed: August 31, 2004
    Date of Patent: July 4, 2006
    Assignee: Micron Technology, Inc.
    Inventors: Jason B. Elledge, Nagasubramaniyan Chandrasekaran
  • Publication number: 20060128273
    Abstract: 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: Application
    Filed: February 8, 2006
    Publication date: June 15, 2006
    Applicant: Micron Technology, Inc.
    Inventor: Nagasubramaniyan Chandrasekaran
  • Patent number: 7033246
    Abstract: 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: Grant
    Filed: August 31, 2004
    Date of Patent: April 25, 2006
    Assignee: Micron Technology, Inc.
    Inventors: Jason B. Elledge, Nagasubramaniyan Chandrasekaran
  • Patent number: 7033248
    Abstract: 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: Grant
    Filed: August 31, 2004
    Date of Patent: April 25, 2006
    Assignee: Micron Technology, Inc.
    Inventors: Jason B. Elledge, Nagasubramaniyan Chandrasekaran
  • Publication number: 20060073767
    Abstract: 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: Application
    Filed: December 1, 2005
    Publication date: April 6, 2006
    Applicant: Micron Technology, Inc.
    Inventor: Nagasubramaniyan Chandrasekaran
  • Patent number: 7011566
    Abstract: 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: Grant
    Filed: August 26, 2002
    Date of Patent: March 14, 2006
    Assignee: Micron Technology, Inc.
    Inventor: Nagasubramaniyan Chandrasekaran
  • Patent number: 7008299
    Abstract: 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: Grant
    Filed: August 29, 2002
    Date of Patent: March 7, 2006
    Assignee: Micron Technology, Inc.
    Inventor: Nagasubramaniyan Chandrasekaran
  • Patent number: 7004817
    Abstract: 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: Grant
    Filed: August 23, 2002
    Date of Patent: February 28, 2006
    Assignee: Micron Technology, Inc.
    Inventor: Nagasubramaniyan Chandrasekaran
  • Publication number: 20050260927
    Abstract: 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: Application
    Filed: July 28, 2005
    Publication date: November 24, 2005
    Applicant: Micron Technology, Inc.
    Inventor: Nagasubramaniyan Chandrasekaran
  • Publication number: 20050239382
    Abstract: 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: Application
    Filed: June 28, 2005
    Publication date: October 27, 2005
    Applicant: Micron Technology, Inc.
    Inventors: Theodore Taylor, Nagasubramaniyan Chandrasekaran
  • Patent number: 6958001
    Abstract: 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: Grant
    Filed: December 13, 2004
    Date of Patent: October 25, 2005
    Assignee: Micron Technology, Inc.
    Inventor: Nagasubramaniyan Chandrasekaran
  • Publication number: 20050205523
    Abstract: 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: Application
    Filed: April 21, 2005
    Publication date: September 22, 2005
    Applicant: Micron Technology, Inc.
    Inventors: Nagasubramaniyan Chandrasekaran, Theodore Taylor
  • Patent number: 6939211
    Abstract: 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: Grant
    Filed: October 9, 2003
    Date of Patent: September 6, 2005
    Assignee: Micron Technology, Inc.
    Inventors: Theodore M. Taylor, Nagasubramaniyan Chandrasekaran
  • Publication number: 20050118930
    Abstract: 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: Application
    Filed: December 13, 2004
    Publication date: June 2, 2005
    Inventor: Nagasubramaniyan Chandrasekaran
  • Patent number: 6884144
    Abstract: 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: Grant
    Filed: August 16, 2002
    Date of Patent: April 26, 2005
    Assignee: Micron Technology, Inc.
    Inventors: Nagasubramaniyan Chandrasekaran, Theodore M. Taylor