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: 20210151338Abstract: A wafer storage device may include one or more mutually aligned rails extending from two opposing side walls, each pair of mutually aligned rails configured to support a wafer between the side walls. The wafer storage device includes one or more sensors coupled to at least some of the one or more rails. The one or more sensors may be configured to detect a physical property of the wafer. The wafer storage device may further include a processor configured to analyze data from the one or more sensors, and a memory device. The memory device may be configured to store data produced by at least the one or more sensors or the processor. The wafer storage device may also include a power storage device configured to receive power from an external source and supply power to the one or more sensors and the processor.Type: ApplicationFiled: November 19, 2019Publication date: May 20, 2021Inventor: Nagasubramaniyan Chandrasekaran
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Patent number: 7988529Abstract: Methods and apparatus for controlling the removal of material from microfeature workpieces in abrasive removal processes. An embodiment of such a method comprises irradiating a periodic structure of the workpiece and obtaining an intensity distribution of radiation returning from the periodic structure. The workpiece can be irradiated with a wide spectrum of wavelengths (e.g., white light), or the workpiece can be irradiated with a laser or lamp at specific wavelengths. The intensity distribution can be an image or other signal from which a dimension or other physical parameter of the periodic structure can be determined. For example, the intensity distribution can be an intensity signal of radiation returning from the workpiece in a selected bandwidth (e.g., 200 nm-900 nm) or an image of a diffraction pattern of radiation that has been scattered by the periodic structure. The method further includes outputting a control signal based on the obtained intensity distribution.Type: GrantFiled: March 25, 2009Date of Patent: August 2, 2011Assignee: Micron Technology, Inc.Inventors: Nagasubramaniyan Chandrasekaran, Rajshree Kothari, Gundu M. Sabde, James J. Hofmann
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Publication number: 20090181601Abstract: Methods and apparatus for controlling the removal of material from microfeature workpieces in abrasive removal processes. An embodiment of such a method comprises irradiating a periodic structure of the workpiece and obtaining an intensity distribution of radiation returning from the periodic structure. The workpiece can be irradiated with a wide spectrum of wavelengths (e.g., white light), or the workpiece can be irradiated with a laser or lamp at specific wavelengths. The intensity distribution can be an image or other signal from which a dimension or other physical parameter of the periodic structure can be determined. For example, the intensity distribution can be an intensity signal of radiation returning from the workpiece in a selected bandwidth (e.g., 200 nm-900 nm) or an image of a diffraction pattern of radiation that has been scattered by the periodic structure. The method further includes outputting a control signal based on the obtained intensity distribution.Type: ApplicationFiled: March 25, 2009Publication date: July 16, 2009Applicant: Micron Technology, Inc.Inventors: Nagasubramaniyan Chandrasekaran, Rajshree Kothari, Gundu M. Sabde, James J. Hofmann
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Patent number: 7527545Abstract: Methods and apparatus for controlling the removal of material from microfeature workpieces in abrasive removal processes. An embodiment of such a method comprises irradiating a periodic structure of the workpiece and obtaining an intensity distribution of radiation returning from the periodic structure. The workpiece can be irradiated with a wide spectrum of wavelengths (e.g., white light), or the workpiece can be irradiated with a laser or lamp at specific wavelengths. The intensity distribution can be an image or other signal from which a dimension or other physical parameter of the periodic structure can be determined. For example, the intensity distribution can be an intensity signal of radiation returning from the workpiece in a selected bandwidth (e.g., 200 nm-900 nm) or an image of a diffraction pattern of radiation that has been scattered by the periodic structure. The method further includes outputting a control signal based on the obtained intensity distribution.Type: GrantFiled: August 28, 2006Date of Patent: May 5, 2009Assignee: Micron Technology, Inc.Inventors: Nagasubramaniyan Chandrasekaran, Rajshree Kothari, Gundu M. Sabde, James J. Hofmann
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Patent number: 7381647Abstract: 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: April 21, 2005Date of Patent: June 3, 2008Assignee: Micron Technology, Inc.Inventors: Nagasubramaniyan Chandrasekaran, Theodore M. Taylor
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Patent number: 7347767Abstract: Retaining rings and associated planarizing apparatuses, and related methods for planarizing micro-device workpieces are disclosed herein. A carrier head configured in accordance with one embodiment of the invention can be used to retain a micro-device workpiece during mechanical or chemical-mechanical polishing. In this embodiment, the carrier head can include a retaining ring carried by a workpiece holder. The retaining ring can include an inner surface, an outer surface, and a base surface extending at least partially between the inner and outer surfaces. The retaining ring can further include at least one annular groove and a plurality of transverse grooves. The annular groove can be positioned adjacent to the base surface between the inner and outer surfaces. The plurality of transverse grooves can extend from the inner surface of the retaining ring to the annular groove in the base surface.Type: GrantFiled: February 21, 2007Date of Patent: March 25, 2008Assignee: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Publication number: 20080051007Abstract: Methods and apparatus for controlling the removal of material from microfeature workpieces in abrasive removal processes. An embodiment of such a method comprises irradiating a periodic structure of the workpiece and obtaining an intensity distribution of radiation returning from the periodic structure. The workpiece can be irradiated with a wide spectrum of wavelengths (e.g., white light), or the workpiece can be irradiated with a laser or lamp at specific wavelengths. The intensity distribution can be an image or other signal from which a dimension or other physical parameter of the periodic structure can be determined. For example, the intensity distribution can be an intensity signal of radiation returning from the workpiece in a selected bandwidth (e.g., 200 nm-900 nm) or an image of a diffraction pattern of radiation that has been scattered by the periodic structure. The method further includes outputting a control signal based on the obtained intensity distribution.Type: ApplicationFiled: August 28, 2006Publication date: February 28, 2008Applicant: Micron Technology, Inc.Inventors: Nagasubramaniyan Chandrasekaran, Rajshree Kothari, Gundu M. Sabde, James J. Hofmann
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Patent number: 7326105Abstract: Retaining rings and associated planarizing apparatuses, and related methods for planarizing micro-device workpieces are disclosed herein. A carrier head configured in accordance with one embodiment of the invention can be used to retain a micro-device workpiece during mechanical or chemical-mechanical polishing. In this embodiment, the carrier head can include a retaining ring carried by a workpiece holder. The retaining ring can include an inner surface, an outer surface, and a base surface extending at least partially between the inner and outer surfaces. The retaining ring can further include at least one annular groove and a plurality of transverse grooves. The annular groove can be positioned adjacent to the base surface between the inner and outer surfaces. The plurality of transverse grooves can extend from the inner surface of the retaining ring to the annular groove in the base surface.Type: GrantFiled: August 31, 2005Date of Patent: February 5, 2008Assignee: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Patent number: 7314401Abstract: 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: October 10, 2006Date of Patent: January 1, 2008Assignee: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Patent number: 7258596Abstract: 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: June 7, 2006Date of Patent: August 21, 2007Assignee: Micron Technology, Inc.Inventors: Jason B. Elledge, Nagasubramaniyan Chandrasekaran
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Patent number: 7235000Abstract: 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: February 8, 2006Date of Patent: June 26, 2007Assignee: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Publication number: 20070141959Abstract: Retaining rings and associated planarizing apparatuses, and related methods for planarizing micro-device workpieces are disclosed herein. A carrier head configured in accordance with one embodiment of the invention can be used to retain a micro-device workpiece during mechanical or chemical-mechanical polishing. In this embodiment, the carrier head can include a retaining ring carried by a workpiece holder. The retaining ring can include an inner surface, an outer surface, and a base surface extending at least partially between the inner and outer surfaces. The retaining ring can further include at least one annular groove and a plurality of transverse grooves. The annular groove can be positioned adjacent to the base surface between the inner and outer surfaces. The plurality of transverse grooves can extend from the inner surface of the retaining ring to the annular groove in the base surface.Type: ApplicationFiled: February 21, 2007Publication date: June 21, 2007Applicant: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Publication number: 20070141960Abstract: Retaining rings and associated planarizing apparatuses, and related methods for planarizing micro-device workpieces are disclosed herein. A carrier head configured in accordance with one embodiment of the invention can be used to retain a micro-device workpiece during mechanical or chemical-mechanical polishing. In this embodiment, the carrier head can include a retaining ring carried by a workpiece holder. The retaining ring can include an inner surface, an outer surface, and a base surface extending at least partially between the inner and outer surfaces. The retaining ring can further include at least one annular groove and a plurality of transverse grooves. The annular groove can be positioned adjacent to the base surface between the inner and outer surfaces. The plurality of transverse grooves can extend from the inner surface of the retaining ring to the annular groove in the base surface.Type: ApplicationFiled: February 21, 2007Publication date: June 21, 2007Applicant: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Publication number: 20070135027Abstract: Retaining rings and associated planarizing apparatuses, and related methods for planarizing micro-device workpieces are disclosed herein. A carrier head configured in accordance with one embodiment of the invention can be used to retain a micro-device workpiece during mechanical or chemical-mechanical polishing. In this embodiment, the carrier head can include a retaining ring carried by a workpiece holder. The retaining ring can include an inner surface, an outer surface, and a base surface extending at least partially between the inner and outer surfaces. The retaining ring can further include at least one annular groove and a plurality of transverse grooves. The annular groove can be positioned adjacent to the base surface between the inner and outer surfaces. The plurality of transverse grooves can extend from the inner surface of the retaining ring to the annular groove in the base surface.Type: ApplicationFiled: February 21, 2007Publication date: June 14, 2007Applicant: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Patent number: 7223297Abstract: 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: June 28, 2005Date of Patent: May 29, 2007Assignee: Micron Technology, Inc.Inventors: Theodore M. Taylor, Nagasubramaniyan Chandrasekaran
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Patent number: 7201635Abstract: 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: June 29, 2006Date of Patent: April 10, 2007Assignee: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Publication number: 20070049179Abstract: Retaining rings and associated planarizing apparatuses, and related methods for planarizing micro-device workpieces are disclosed herein. A carrier head configured in accordance with one embodiment of the invention can be used to retain a micro-device workpiece during mechanical or chemical-mechanical polishing. In this embodiment, the carrier head can include a retaining ring carried by a workpiece holder. The retaining ring can include an inner surface, an outer surface, and a base surface extending at least partially between the inner and outer surfaces. The retaining ring can further include at least one annular groove and a plurality of transverse grooves. The annular groove can be positioned adjacent to the base surface between the inner and outer surfaces. The plurality of transverse grooves can extend from the inner surface of the retaining ring to the annular groove in the base surface.Type: ApplicationFiled: August 31, 2005Publication date: March 1, 2007Applicant: Micro Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Publication number: 20070032171Abstract: 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: October 10, 2006Publication date: February 8, 2007Applicant: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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Patent number: 7163439Abstract: 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: February 8, 2006Date of Patent: January 16, 2007Assignee: Micron Technology, Inc.Inventor: Nagasubramaniyan Chandrasekaran
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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