Patents by Inventor Aseem K. Srivastava
Aseem K. Srivastava 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: 20210082695Abstract: A method of forming an electrically insulating barrier between a source contact and a drain contact of a transistor device including an electrically insulating layer disposed atop a semi-conductive layer, and an electrically conductive layer disposed atop the electrically insulating layer, the source contact and the drain contact extending from the electrically conductive layer through the electrically insulating layer to the semi-conductive layer, the method including disposing a hardmask layer atop the electrically conductive layer, disposing a photoresist layer atop the hardmask layer, performing a photolithography process to form a trench in the hardmask layer to expose an underlying portion of the electrically conductive layer spanning between the source contact and the drain contact, and performing an ion implantation process, wherein an ion beam formed of ionized oxygen atoms is directed into the trench to oxidize the exposed portion of the electrically conductive layer.Type: ApplicationFiled: September 17, 2019Publication date: March 18, 2021Applicant: APPLIED Materials, Inc.Inventor: Aseem K. Srivastava
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Patent number: 10937646Abstract: A method of forming an electrically insulating barrier between a source contact and a drain contact of a transistor device including an electrically insulating layer disposed atop a semi-conductive layer, and an electrically conductive layer disposed atop the electrically insulating layer, the source contact and the drain contact extending from the electrically conductive layer through the electrically insulating layer to the semi-conductive layer, the method including disposing a hardmask layer atop the electrically conductive layer, disposing a photoresist layer atop the hardmask layer, performing a photolithography process to form a trench in the hardmask layer to expose an underlying portion of the electrically conductive layer spanning between the source contact and the drain contact, and performing an ion implantation process, wherein an ion beam formed of ionized oxygen atoms is directed into the trench to oxidize the exposed portion of the electrically conductive layer.Type: GrantFiled: September 17, 2019Date of Patent: March 2, 2021Assignee: Applied Materials, Inc.Inventor: Aseem K. Srivastava
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Patent number: 9783884Abstract: Methods of decreasing the dose per pulse implanted into a workpiece disposed in a process chamber are disclosed. According to one embodiment, the plasma is generated by a RF power supply. This RF power supply may have two different modes, a first, referred to as continuous wave mode, where the RF power supply is continuously outputting a voltage. This mode allows creation of the plasma within the process chamber. During the second mode, referred to as pulsed plasma mode, the RF power supply outputs two different power levels. The platen bias voltage may be a more negative value when the lower RF power level is being applied. This pulsed (or multi-setpoint) plasma also assists in reducing dopant deposition on the wafer during the time when CW plasma is on but the bias voltage pulse is in the off-state. In a further embodiment, a delay is introduced between the transition to the pulsed plasma mode and the initiation of the implanting process.Type: GrantFiled: February 28, 2014Date of Patent: October 10, 2017Assignee: Varian Semiconductor Equipment Associates, Inc.Inventors: Ilwoong Koo, Jun Lee, Aseem K. Srivastava
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Patent number: 8932430Abstract: The present disclosure is directed towards a method and apparatus for generating an abatement plasma downstream of a processing chamber using an RF plasma ignited and sustained with an integrated power oscillator circuit driven by feedback based upon a load of the abatement plasma. In one embodiment, a plasma ashing system includes an abatement system configured to receive an effluent byproduct from an upstream processing chamber containing a workpiece. The effluent byproduct is provided along an exhaust conduit to a downstream afterburner unit having an integrated power oscillator, that relies upon an oscillating circuit operatively coupled to an antenna to ignite the abatement plasma within the exhaust conduit. The antenna, together with the plasma load, form a resonant tank circuit, which provides a feedback that drives operation of the oscillating circuit, thereby allowing the oscillating circuit to vary its output based upon changes in the abatement plasma load.Type: GrantFiled: May 6, 2011Date of Patent: January 13, 2015Assignee: Axcelis Technologies, Inc.Inventors: Aseem K. Srivastava, William F. DiVergilio
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Patent number: 8906195Abstract: A continuously variable microwave circuit capable of being tuned to operate under a plurality of distinct operating conditions, comprising: a waveguide comprising an adjustable tuning element having a core configured to protrude into the waveguide; an actuator in operative communication with the adjustable tuning element, wherein the actuator is operable to selectively vary a length of the core that is protruding into the waveguide so as to minimize reflected microwave power in the plasma asher; and a controller in operative communication with the actuator, wherein the controller is configured to selectively activate the actuator upon a change in the plurality of operating conditions.Type: GrantFiled: November 18, 2009Date of Patent: December 9, 2014Assignee: Lam Research CorporationInventors: Aseem K. Srivastava, Robert P. Couilliard
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Publication number: 20140272182Abstract: Methods of decreasing the dose per pulse implanted into a workpiece disposed in a process chamber are disclosed. According to one embodiment, the plasma is generated by a RF power supply. This RF power supply may have two different modes, a first, referred to as continuous wave mode, where the RF power supply is continuously outputting a voltage. This mode allows creation of the plasma within the process chamber. During the second mode, referred to as pulsed plasma mode, the RF power supply outputs two different power levels. The platen bias voltage may be a more negative value when the lower RF power level is being applied. This pulsed (or multi-setpoint) plasma also assists in reducing dopant deposition on the wafer during the time when CW plasma is on but the bias voltage pulse is in the off-state. In a further embodiment, a delay is introduced between the transition to the pulsed plasma mode and the initiation of the implanting process.Type: ApplicationFiled: February 28, 2014Publication date: September 18, 2014Inventors: Ilwoong Koo, Jun Lee, Aseem K. Srivastava
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Publication number: 20130305989Abstract: Some techniques disclosed herein facilitate cleaning residue from a molecular beam component. For example, in an exemplary method, a molecular beam is provided along a beam path, causing residue build up on the molecular beam component. To reduce the residue, the molecular beam component is exposed to a hydro-fluorocarbon plasma. Exposure to the hydro-fluorocarbon plasma is ended based on whether a first predetermined condition is met, the first predetermined condition indicative of an extent of removal of the residue. Other methods and systems are also disclosed.Type: ApplicationFiled: July 23, 2013Publication date: November 21, 2013Applicant: Axcelis Technologies, Inc.Inventors: Aseem K. Srivastava, William F. DiVergilio, Glen R. Gilchrist
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Publication number: 20130160793Abstract: An apparatus configured to provide simultaneous plasma and electromagnetic irradiation of a workpiece within the same process chamber, thereby providing processes that permit simultaneous plasma and electromagnetic irradiation within the same atmosphere as may be desired for some applications.Type: ApplicationFiled: December 22, 2011Publication date: June 27, 2013Applicant: AXCELIS TECHNOLOGIES, INC.Inventors: Aseem K. Srivastava, Ivan Berry
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Publication number: 20120279657Abstract: The present disclosure is directed towards a method and apparatus for generating an abatement plasma downstream of a processing chamber using an RF plasma ignited and sustained with an integrated power oscillator circuit driven by feedback based upon a load of the abatement plasma. In one embodiment, a plasma ashing system includes an abatement system configured to receive an effluent byproduct from an upstream processing chamber containing a workpiece. The effluent byproduct is provided along an exhaust conduit to a downstream afterburner unit having an integrated power oscillator, that relies upon an oscillating circuit operatively coupled to an antenna to ignite the abatement plasma within the exhaust conduit. The antenna, together with the plasma load, form a resonant tank circuit, which provides a feedback that drives operation of the oscillating circuit, thereby allowing the oscillating circuit to vary its output based upon changes in the abatement plasma load.Type: ApplicationFiled: May 6, 2011Publication date: November 8, 2012Applicant: Axcelis Technologies, Inc.Inventors: Aseem K. Srivastava, William F. DiVergilio
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Publication number: 20110114115Abstract: A continuously variable microwave circuit capable of being tuned to operate under a plurality of distinct operating conditions, comprising: a waveguide comprising an adjustable tuning element having a core configured to protrude into the waveguide; an actuator in operative communication with the adjustable tuning element, wherein the actuator is operable to selectively vary a length of the core that is protruding into the waveguide so as to minimize reflected microwave power in the plasma asher; and a controller in operative communication with the actuator, wherein the controller is configured to selectively activate the actuator upon a change in the plurality of operating conditions.Type: ApplicationFiled: November 18, 2009Publication date: May 19, 2011Applicant: AXCELIS TECHNOLOGIESM INC.Inventors: Aseem K. Srivastava, Robert P. Couilliard
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Publication number: 20110108058Abstract: Some techniques disclosed herein facilitate cleaning residue from a molecular beam component. For example, in an exemplary method, a molecular beam is provided along a beam path, causing residue build up on the molecular beam component. To reduce the residue, the molecular beam component is exposed to a hydro-fluorocarbon plasma. Exposure to the hydro-fluorocarbon plasma is ended based on whether a first predetermined condition is met, the first predetermined condition indicative of an extent of removal of the residue. Other methods and systems are also disclosed.Type: ApplicationFiled: November 11, 2009Publication date: May 12, 2011Applicant: Axcelis Technologies, Inc.Inventors: Aseem K. Srivastava, William F. DiVergilio, Glen R. Gilchrist
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Patent number: 7892357Abstract: A baffle plate assembly for distributing gas flows into an adjacent process chamber containing a semiconductor wafer to be processed includes a planar gas distribution portion having a plurality of apertures therein; a flange surrounding the gas distribution portion; and an impingement device centrally attached to the gas distribution portion, wherein the device includes a cap and a stem, the stem being in thermal contact with the gas distribution portion. Also disclosed herein are plasma reactors employing the baffle plate assembly and methods for reducing recombination of species in a plasma.Type: GrantFiled: January 12, 2004Date of Patent: February 22, 2011Assignee: Axcelis Technologies, Inc.Inventor: Aseem K. Srivastava
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Publication number: 20110036500Abstract: An antenna array for a radio frequency plasma process chamber including, an array of electrodes, an array of dielectric tubes concentrically disposed about each electrode tube to define a chamber configured to be at atmospheric pressure between an outer surface of each electrode tube and an inner surface of the corresponding dielectric tube, and a hermetic seal between each dielectric tube and the plasma process chamber configured to allow a vacuum or low pressure environment in the plasma process chamber.Type: ApplicationFiled: October 22, 2010Publication date: February 17, 2011Applicant: AXCELIS TECHNOLOGIES, INC.Inventors: William F. DiVergilio, Aseem K. Srivastava
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Patent number: 7845310Abstract: An antenna array for a radio frequency plasma process chamber including, an array of electrodes, an array of dielectric tubes concentrically disposed about each electrode tube to define a chamber configured to be at atmospheric pressure between an outer surface of each electrode tube and an inner surface of the corresponding dielectric tube, and a hermetic seal between each dielectric tube and the plasma process chamber configured to allow a vacuum or low pressure in the plasma process chamber.Type: GrantFiled: December 6, 2006Date of Patent: December 7, 2010Assignee: Axcelis Technologies, Inc.Inventors: William F. DiVergilio, Aseem K. Srivastava
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Publication number: 20080138992Abstract: An antenna array for a radio frequency plasma process chamber including, an array of electrodes, an array of dielectric tubes concentrically disposed about each electrode tube to define a chamber configured to be at atmospheric pressure between an outer surface of each electrode tube and an inner surface of the corresponding dielectric tube, and a hermetic seal between each dielectric tube and the plasma process chamber configured to allow a vacuum or low pressure in the plasma process chamber.Type: ApplicationFiled: December 6, 2006Publication date: June 12, 2008Inventors: William F. DiVergilio, Aseem K. Srivastava
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Patent number: 6225745Abstract: A dual plasma source (80) is provided for a plasma processing system (10), comprising a first plasma source (82) and a second plasma source (84). The first plasma source (82) has a first plasma passageway (86) for transporting a first plasma therethrough toward a processing chamber (16), the first plasma passageway providing a first inlet (90) for accepting a first gas mixture to be energized by the first plasma source. The second plasma source (84) is connected to the first plasma source (82) and has a second plasma passageway (88) for transporting a second plasma therethrough toward the processing chamber (16), the second plasma passageway providing a second inlet (92) for accepting a second gas mixture to be energized by the second plasma source. The first plasma passageway (86) is constructed from a material that resists atomic oxygen recombination with the first plasma, and the second plasma passageway (88) is constructed from a material that resists etching by the second plasma.Type: GrantFiled: December 17, 1999Date of Patent: May 1, 2001Assignee: Axcelis Technologies, Inc.Inventor: Aseem K. Srivastava
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Patent number: 6057645Abstract: A plasma discharge device and method for removing material from a substrate having dynamic tuning, which permits operation with a variety of process gasses over a range of operating conditions. A longitudinally extending microwave cavity is defined at the ends by microwave traps, the positions of which are longitudinally adjustable to provide dynamic tuning. An adjustable antenna is provided, and operation utilizes the TM.sub.012 mode.Type: GrantFiled: December 31, 1997Date of Patent: May 2, 2000Assignee: Eaton CorporationInventors: Aseem K. Srivastava, Richard E. Pingree, Victor Pellicier