Patents by Inventor Ali Shajii

Ali Shajii 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).

  • Patent number: 7166187
    Abstract: The present invention is directed to a semiconductor thermal processing system and an apparatus for thermally cooling a semiconductor substrate. According to one aspect of the present invention, a semiconductor thermal processing system and associated apparatus and method are disclosed which provides a segmented cold plate situated within a process chamber, wherein a plurality of segments of the cold plate are operable to radially translate between an engaged position and a disengaged position, wherein a substrate holder may pass between the plurality of segments when the segments are in the disengaged position. According to another aspect, an elevator is operable to linearly translate a substrate residing on a substrate holder between a heating position proximate to a heater assembly and a cooling position proximate to the segmented cold plate.
    Type: Grant
    Filed: June 29, 2004
    Date of Patent: January 23, 2007
    Assignee: Axcelis Technologies, Inc.
    Inventors: Ali Shajii, David Tao, Mathias Koch, Douglas Brown, Hossein Zarrin
  • Patent number: 7136767
    Abstract: A mass flow sensor calibrator employs a variable-flow fluid source, a receptacle of known volume, and a pressure differentiator. The variable-flow fluid source supplies gas at varying rates to the mass flow sensor being calibrated and at proportional rates to a receptacle of known volume. A pressure differentiator computes the time derivative of gas flow into the receptacle of known volume and, from that, the actual flow into the receptacle. Given the actual flow, the proportionate flow into the mass flow sensor may be determined and the flow signal from the mass flow sensor correlated to the actual flow.
    Type: Grant
    Filed: June 24, 2002
    Date of Patent: November 14, 2006
    Assignee: MKS Instruments, Inc.
    Inventors: Ali Shajii, Nicholas Kottenstette, Jesse Ambrosina
  • Patent number: 7121139
    Abstract: A flow rate sensor includes a main conduit, a sensor tube and a bypass tube connecting an upstream portion of the main conduit to a downstream portion of the main conduit such that flow through the main conduit is divided through the sensor tube and the bypass tube, and at least one heater element for heating the sensor tube. A first flow restrictor of porous media is positioned between the upstream portion of the main conduit and the sensor tube, and a second flow restrictor of porous media is positioned between the upstream portion of the main conduit and the bypass tube. The flow restrictors provide the flow rate sensor with a fixed bypass ratio so that the sensor can operate independently of the type of gas being measured.
    Type: Grant
    Filed: November 12, 2004
    Date of Patent: October 17, 2006
    Assignee: MKS Instruments, Inc.
    Inventors: Ali Shajii, Paul Meneghini, Daniel Alexander Smith
  • Patent number: 7120542
    Abstract: A flow monitoring system includes a first temperature-sensitive resistive device, thermally coupled to a first portion of a fluid transfer apparatus, for producing a first temperature-dependant voltage signal representative of the temperature of the fluid within the first portion of the fluid transfer apparatus. A first current control device, coupled to the first temperature-sensitive resistive device, controls a first current signal flowing through the first temperature-sensitive resistive device. A second temperature-sensitive resistive device, thermally coupled to a second portion of the fluid transfer apparatus, produces a second temperature-dependant voltage signal representative of the temperature of the fluid within the second portion of the fluid transfer apparatus. A second current control device, coupled to the second temperature-sensitive resistive device, controls a second current signal flowing through the second temperature-sensitive resistive device.
    Type: Grant
    Filed: March 30, 2004
    Date of Patent: October 10, 2006
    Assignee: MKS Instruments, Inc.
    Inventors: Nicholas Kottenstette, Ali Shajii, Louis Slamka, Siddharth P. Nagarkatti
  • Publication number: 20060217903
    Abstract: A flow verifier for in-situ verification of a device under test (DUT), including an inlet connectable to a DUT, an outlet connectable to a vacuum pump for drawing gas through the DUT and the flow verifier, a vessel having a predetermined volume, diffusive media connecting the inlet to the vessel, an outlet valve connecting the vessel to the outlet for controlling flow from the vessel to the outlet, at least one temperature sensor operatively connected to the vessel for providing temperature measurements from within the vessel, and a pressure transducer operatively connected to the vessel for providing pressure measurements from within the vessel.
    Type: Application
    Filed: March 25, 2005
    Publication date: September 28, 2006
    Inventors: Ali Shajii, Daniel Smith
  • Publication number: 20060217900
    Abstract: A flow verifier for verifying measurement of a flow rate of a fluid by a device includes a flow restrictor that renders the flow rate verification substantially insensitive to elements upstream of the flow restrictor. The flow verifier includes a vessel that receives a flow of the fluid from the device, and a pressure sensor that measures pressure of the fluid within the vessel. An outlet valve regulates flow of the fluid out of the vessel. The flow restrictor is located adjacent to and upstream of the vessel, along a flow path of the fluid. The flow restrictor restricts the flow of the fluid so as to induce a shock in the flow path of the fluid, and sustains the shock during a time period sufficient to render the flow rate verification substantially insensitive to the elements upstream of the flow restrictor.
    Type: Application
    Filed: March 3, 2006
    Publication date: September 28, 2006
    Applicant: MKS instruments, Inc.
    Inventors: Ali Shajii, Daniel Smith
  • Publication number: 20060214127
    Abstract: A valve assembly including a first plate having a first surface defining a port, a second plate received over the first plate such that the port of the first plate is substantially closed by a first surface of the second plate, wherein the second plate is movable away from the first plate to open the port, and a fixed member spaced from a second surface of the second plate, the second surface facing away from the first surface of the second plate. A first linkage has opposing first and second ends, and the first end is positioned adjacent the second surface of the second plate, and a second linkage has opposing first and second ends, and the first end is pivotally connected to the second end of the first linkage and the second end of the second linkage is positioned adjacent the fixed member.
    Type: Application
    Filed: March 25, 2005
    Publication date: September 28, 2006
    Inventors: Ali Shajii, Jesse Ambrosina, Leonard Myatt, Matthew Besen
  • Publication number: 20060207503
    Abstract: A vaporizer including an inlet for liquid and an outlet for gas, a gas valve controlling gas flow to the outlet of the vaporizer, and means for heating liquid flowing between the liquid inlet and the gas valve. The vaporizer also includes means for increasing a heat transfer rate of the liquid flowing between the liquid inlet and the gas valve, and for causing a pressure drop in the liquid so that a pressure of the liquid drops below a vapor transition pressure of the liquid upon reaching the gas valve. The pressure drop occurs under isothermal conditions, and the liquid is vaporized on demand only when the valve is opened. The means for increasing a heat transfer rate and for causing a pressure drop can be a plug of porous media.
    Type: Application
    Filed: March 18, 2005
    Publication date: September 21, 2006
    Inventors: Paul Meneghini, Ali Shajii, Daniel Smith, William Clark
  • Patent number: 7107834
    Abstract: A sensing apparatus for use in a mass flow rate sensor for measuring a fluid flow rate includes a main conduit for containing a fluid flow, and a sensor passageway for tapping a portion of the fluid flow from the main conduit at a first location, and returning the portion of the fluid flow to the conduit at a second location. At least one bypass passageway, which may be provided in the form of a tube, is positioned in the main conduit between the first and second locations, and the bypass passageway is provided with non-negligible entrance effects that are substantially equal to entrance effects of the sensor passageway, so that a bypass ratio of the apparatus remains constant. A mass flow rate sensor of the present disclosure accurately measures any type of gas but only requires calibration in only one reference gas.
    Type: Grant
    Filed: November 12, 2004
    Date of Patent: September 19, 2006
    Assignee: MKS Instruments, Inc.
    Inventors: Paul Meneghini, Ali Shajii
  • Publication number: 20060169327
    Abstract: A pressure control system remotely controls pressure within one or more remote zones, each respectively connected to an enclosure through a conduit, by controlling flow of a fluid into and out of each enclosure. The pressure of the fluid is measured within each enclosure. An estimated pressure within each zone is computed, as a function of the measured pressure in the enclosure and known characteristics of the conduit and the zone. For each zone, an inlet proportional valve and an outlet proportional valve of each enclosure is operated so as to control the input flow rate of the fluid into the respective enclosure and the output flow rate of the fluid out of the enclosure as a function of a pressure set point and the estimated pressure, thereby regulating pressure within the zone in accordance with the pressure set point.
    Type: Application
    Filed: January 17, 2006
    Publication date: August 3, 2006
    Inventors: Ali Shajii, Siddharth Nagarkatti, Gordon Hill
  • Publication number: 20060173642
    Abstract: A mass flow controller includes a thermal mass flow sensor in combination with a pressure sensor to provide a mass flow controller that is relatively insensitive to fluctuations in input pressure. The pressure sensor and thermal sensor respectively provide signals to an electronic controller indicating the measured inlet flow rate and the pressure within the dead volume. The electronic controller employs the measured pressure to compensate the measured inlet flow rate and to thereby produce a compensated measure of the outlet flow rate, which may be used to operate a mass flow controller control valve.
    Type: Application
    Filed: December 15, 2005
    Publication date: August 3, 2006
    Inventors: Ali Shajii, Nicholas Kottenstette, Jesse Ambrosina
  • Patent number: 7073771
    Abstract: A valve assembly for controlling the flow of a predetermined fluid, including a tube having an open end forming an outlet port, and wherein the tube is made of a material that is porous with respect to the predetermined fluid, an outer wall forming a fluid chamber coaxially surrounding the porous tube and including an inlet port, and a valve member made of non-porous material received for sliding movement within the porous tube. Sliding movement of the valve member within the tube and towards the open end of the tube reduces the flow of the predetermined fluid from the fluid chamber, through the porous tube and through the outlet of the valve assembly, while sliding movement of the valve member within the tube and away from the open end of the tube increases the flow of the predetermined fluid from the fluid chamber, through the porous tube and through the outlet of the valve assembly.
    Type: Grant
    Filed: March 30, 2004
    Date of Patent: July 11, 2006
    Assignee: MKS Instruments, Inc.
    Inventors: Ali Shajii, Ronald W. Collins, Jr., Matthew Besen
  • Patent number: 7072743
    Abstract: A system for dividing a single flow into two or more secondary flows of desired ratios, including an inlet adapted to receive the single flow, at least two secondary flow lines connected to the inlet, an input device adapted to receive at least one desired ratio of flow, at least one in-situ process monitor providing measurements of products produced by each of the flows lines, and a controller connected to the input device and the in-situ process monitor. The controller is programmed to receive the desired ratio of flow through the input device, receive the product measurements from the in-situ process monitor, and calculate a corrected ratio of flow based upon the desired ratio of flow and the product measurements. If the product measurements are not equal, then the corrected ratio of flow will be different than the desired ratio of flow.
    Type: Grant
    Filed: March 9, 2004
    Date of Patent: July 4, 2006
    Assignee: MKS Instruments, Inc.
    Inventors: Ali Shajii, Siddharth P. Nagarkatti
  • Publication number: 20060101908
    Abstract: A sensing apparatus for use in a mass flow rate sensor for measuring a fluid flow rate includes a main conduit for containing a fluid flow, and a sensor passageway for tapping a portion of the fluid flow from the main conduit at a first location, and returning the portion of the fluid flow to the conduit at a second location. At least one bypass passageway, which may be provided in the form of a tube, is positioned in the main conduit between the first and second locations, and the bypass passageway is provided with non-negligible entrance effects that are substantially equal to entrance effects of the sensor passageway, so that a bypass ratio of the apparatus remains constant. A mass flow rate sensor of the present disclosure accurately measures any type of gas but only requires calibration in only one reference gas.
    Type: Application
    Filed: November 12, 2004
    Publication date: May 18, 2006
    Inventors: Paul Meneghini, Ali Shajii
  • Publication number: 20060101907
    Abstract: A flow rate sensor includes a main conduit, a sensor tube and a bypass tube connecting an upstream portion of the main conduit to a downstream portion of the main conduit such that flow through the main conduit is divided through the sensor tube and the bypass tube, and at least one heater element for heating the sensor tube. A first flow restrictor of porous media is positioned between the upstream portion of the main conduit and the sensor tube, and a second flow restrictor of porous media is positioned between the upstream portion of the main conduit and the bypass tube. The flow restrictors provide the flow rate sensor with a fixed bypass ratio so that the sensor can operate independently of the type of gas being measured.
    Type: Application
    Filed: November 12, 2004
    Publication date: May 18, 2006
    Inventors: Ali Shajii, Paul Meneghini, Daniel Smith
  • Publication number: 20060060139
    Abstract: A system and method are described that control the amount of precursor that is delivered to a process chamber by precisely measuring the mole fraction of the gas mixture being delivered. A gas delivery system includes a delivery chamber, a precursor inlet valve, a carrier inlet valve, an outlet valve, and a controller. The controller controls the opening and closing of the precursor inlet valve, the carrier inlet valve, and the outlet valve, so as to introduce a desired amount of a precursor gas and a carrier gas into the delivery chamber, to generate a gas mixture having a desired mole fraction of the precursor gas, and to deliver to the process chamber the gas mixture having the desired mole fraction of the precursor gas.
    Type: Application
    Filed: September 9, 2005
    Publication date: March 23, 2006
    Applicant: MKS Instruments, Inc.
    Inventors: Paul Meneghini, Daniel Smith, Ali Shajii
  • Patent number: 7007707
    Abstract: A system for dividing a single mass flow, including an inlet adapted to receive the single mass flow and at least two flow lines connected to the inlet. Each flow line includes a flow meter and a valve. The system also includes a controller programmed to receive a desired ratio of flow through a user interface, receive signals indicative of measured flow from the flow meters, calculate an actual ratio of flow through the flow lines based upon the measured flows, and compare the actual ratio to the desired ratio. The controller is also programmed to calculate the desired flow through at least one of the flow lines if the actual ratio is unequal to the desired ratio, and provide a signal indicative of the desired flow to at least one of the valves.
    Type: Grant
    Filed: April 1, 2004
    Date of Patent: March 7, 2006
    Assignee: MKS Instruments, Inc.
    Inventors: Jesse Ambrosina, Nicholas E. Kottenstette, Ali Shajii
  • Patent number: 7004191
    Abstract: A mass flow controller includes an electronic controller that provides a web server that allows access to the web server through such interworking networks as the Internet.
    Type: Grant
    Filed: June 24, 2002
    Date of Patent: February 28, 2006
    Assignee: MKS Instruments, Inc.
    Inventors: Ali Shajii, Nicholas Kottenstette, Jesse Ambrosina
  • Patent number: 7000463
    Abstract: A mass flow rate sensor uses a Reynolds number correction function to compensate for errors in a bypass ratio of the sensor for all gases, based on the fact that all bypass errors are functions of Reynolds number. The sensor includes a sensor tube and a bypass tube dividing flow, wherein a bypass ratio of the sensor equals a total flow rate through the sensor divided by a flow rate through just the sensor tube. Heater elements heat an upstream portion and a downstream portion of the sensor tube, and a circuit is connected to the heater elements for producing a voltage based upon a difference in resistance between the heater elements. The voltage is calibrated based on known flow rates of a reference gas, and the flow rate through the sensor is based upon the calibrated voltage multiplied by a multi-gas correction function and a Reynolds number correction function.
    Type: Grant
    Filed: November 12, 2004
    Date of Patent: February 21, 2006
    Assignee: MKS Instruments, Inc.
    Inventors: Ali Shajii, Paul Meneghini
  • Patent number: 6986359
    Abstract: A system for controlling fluid flow through i lines, wherein the i lines are connectable through tubing to i zones, respectively, and wherein i=1, 2, . . . , N. The system includes at least one valve and a pressure transducer in each of the i lines, a control device for controlling the valves, and a zone pressure estimator. The zone pressure estimator is connected to the pressure transducers and is programmed to calculate an estimated pressure in each the i zones and provide the estimated pressures to the control device.
    Type: Grant
    Filed: March 9, 2004
    Date of Patent: January 17, 2006
    Assignee: MKS Instruments, Inc.
    Inventors: Ali Shajii, Siddharth P. Nagarkatti