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).

  • Publication number: 20050223979
    Abstract: A system for delivering a desired mass of gas, including a chamber, a first valve controlling flow into the chamber, a second valve controlling flow out of the chamber, a pressure transducer connected to the chamber, an input device for providing a desired mass to be delivered, and a controller connected to the valves, the pressure transducer and the input device. The controller is programmed to receive the desired mass from the input device, close the second valve and open the first valve, receive chamber pressure measurements from the pressure transducer, and close the inlet valve when pressure within the chamber reaches a predetermined level. The controller is then programmed to wait a predetermined waiting period to allow the gas inside the chamber to approach a state of equilibrium, then open the outlet valve at time=t0, and close the outlet valve at time=t* when the mass of gas discharged equals the desired mass.
    Type: Application
    Filed: April 12, 2004
    Publication date: October 13, 2005
    Inventors: Ali Shajii, Siddharth Nagarkatti, Matthew Besen, William Clark, Daniel Smith, Bora Akgerman
  • Publication number: 20050222782
    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: Application
    Filed: March 30, 2004
    Publication date: October 6, 2005
    Inventors: Nicholas Kottenstette, Ali Shajii, Louis Slamka, Siddharth Nagarkatti
  • Publication number: 20050217346
    Abstract: A flow measurement calibration system and method is presented that actively regulates the pressure of the fluid being tested. A piston is slidably mounted to an inner wall of a chamber, which has a fluid inlet port for receiving an inflow of fluid into the interior of the chamber. The piston moves through the length of the chamber in response to fluid pressure exerted by the fluid flowing into the chamber. A piston actuator imparts motion to the piston, in response to command signals from a controller. The controller is responsive to the output of a pressure sensor, which senses the fluid pressure, and a position/velocity sensor, which senses the position and velocity of the piston. The controller commands the piston actuator to dynamically adjust the position and velocity of the piston so that the fluid pressure remains substantially constant at a desired setpoint.
    Type: Application
    Filed: April 6, 2004
    Publication date: October 6, 2005
    Inventors: Siddharth Nagarkatti, William Clark, Ali Shajii
  • Publication number: 20050218361
    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: Application
    Filed: March 30, 2004
    Publication date: October 6, 2005
    Inventors: Ali Shajii, Ronald Collins, Matthew Besen
  • Patent number: 6948508
    Abstract: A mass flow controller includes a mass flow sensor and a calibrator configured to perform a self-calibration on the mass flow controller. The calibrator generates flow measurements that are used as “standards” and flow measurements from the mass flow sensor are correlated to flow measurements from the calibrator.
    Type: Grant
    Filed: June 24, 2002
    Date of Patent: September 27, 2005
    Assignee: MKS Instruments, Inc.
    Inventors: Ali Shajii, Nicholas Kottenstette, Jesse Ambrosina, John A. Smith
  • Publication number: 20050199342
    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: Application
    Filed: March 9, 2004
    Publication date: September 15, 2005
    Inventors: Ali Shajii, Siddharth Nagarkatti
  • Publication number: 20050199287
    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: Application
    Filed: March 9, 2004
    Publication date: September 15, 2005
    Inventors: Ali Shajii, Siddharth Nagarkatti
  • Patent number: 6932098
    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: Grant
    Filed: March 23, 2004
    Date of Patent: August 23, 2005
    Assignee: MKS Instruments, Inc.
    Inventors: Ali Shajii, Nicholas Kottenstette, Jesse Ambrosina, Donald K. Smith, William R. Clark
  • Patent number: 6918295
    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 capillary tube 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. The capillary tube is disposed about a centerline, and includes an inner wall defined by an inside radius measured from the centerline. The inside radius varies periodically, preferably sinusoidally, along the centerline for at least a portion of the capillary tube, thereby forming a turbulated surface on the inner wall. The turbulated inner wall increases wall surface area, and fluid mixing. The resulting increased heat transfer rate decreases the error in sensor output from nonlinear behavior.
    Type: Grant
    Filed: April 1, 2004
    Date of Patent: July 19, 2005
    Assignee: MKS Instruments, Inc.
    Inventors: Ali Shajii, Paul Meneghini, Leonard Myatt
  • Patent number: 6868862
    Abstract: A mass flow controller includes an electronic controller for which a plurality of closed loop control codes sets may be uploaded. In a dual processor embodiment, one processor may upload a plurality of codes sets for another, with the selection of codes sets determined by the uploading processor either autonomously or through user interaction.
    Type: Grant
    Filed: June 24, 2002
    Date of Patent: March 22, 2005
    Assignee: MKS Instruments, Inc.
    Inventors: Ali Shajii, Nicholas Kottenstette, Jesse Ambrosina
  • Patent number: 6868723
    Abstract: A mass flow measurement apparatus including a flow path defined by a tubular side wall, a probe extending through the side wall into the flow path so that a first portion of the probe is located in the flow path and a second portion of the probe, extends out of the side wall, a heater element secured to the probe, and a seal preventing fluid flowing through the flow path from contacting the heater element.
    Type: Grant
    Filed: May 16, 2003
    Date of Patent: March 22, 2005
    Assignee: MKS Instruments, Inc.
    Inventors: Ali Shajii, Nicholas Eugene Kottenstette, R. Leonard Myatt, Jeffrey Vincent Anastas
  • Patent number: 6857323
    Abstract: A method and system is presented for accurately measuring the two phase flow rate of a fluid mixture that includes two different phase components. Capacitance tomography measurements are made in order to determine the concentration ratio of the different phase components within the fluid. Approximate flow measurements are made by transmitting, for example, ultrasound waves through the fluid mixture, and measuring the different speeds of propagation of the ultrasound waves through the different phase components of the fluid mixture. The exact flow rate of the fluid mixture is determined using the concentration ratio obtained from the tomographic measurements, and the approximate flow measurements made, for example, by ultrasound sensing.
    Type: Grant
    Filed: September 23, 2003
    Date of Patent: February 22, 2005
    Assignee: MKS Instruments, Inc.
    Inventors: Ali Shajii, Siddharth P. Nagarkatti, John A. Smith
  • Publication number: 20050026447
    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: Application
    Filed: June 29, 2004
    Publication date: February 3, 2005
    Inventors: Ali Shajii, David Tao, Mathias Koch, Douglas Brown, Hossein Zarrin
  • Publication number: 20040256003
    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: March 23, 2004
    Publication date: December 23, 2004
    Inventors: Ali Shajii, Nicholas Kottenstette, Jesse Ambrosina, Donald K. Smith, William R. Clark
  • Publication number: 20040226358
    Abstract: A mass flow measurement apparatus including a flow path defined by a tubular side wall, a probe extending through the side wall into the flow path so that a first portion of the probe is located in the flow path and a second portion of the probe, extends out of the side wall, a heater element secured to the probe, and a seal preventing fluid flowing through the flow path from contacting the heater element.
    Type: Application
    Filed: May 16, 2003
    Publication date: November 18, 2004
    Inventors: Ali Shajii, Nicholas Eugene Kottenstette, R. Leonard Myatt, Jeffrey Vincent Anastas
  • Patent number: 6813943
    Abstract: An apparatus for conditioning a gas flow to improve a measurement of rate of pressure change associated with the gas flow includes a measurement chamber having an interior portion characterized by an internal volume, and an inlet port for receiving the gas flow. The apparatus includes a pressure sensor and a signal processor. The signal processor receives and samples the pressure signal from the sensor, and calculates a time derivative of the pressure signal. The apparatus also includes an inlet damper disposed at the inlet port, so that the gas flow passes through the inlet damper prior to passing into the measurement chamber. The inlet damper modifies the gas flow according to a damper transfer function. The chamber volume and the damper transfer function are selected so as to the frequencies associated with variations of the pressure in the measurement chamber to a predetermined fraction of the sampling frequency.
    Type: Grant
    Filed: March 19, 2003
    Date of Patent: November 9, 2004
    Assignee: MKS Instruments, Inc.
    Inventors: John A. Smith, Ali Shajii
  • Patent number: 6810308
    Abstract: A mass flow controller includes a network interface port and interface software that provide direct access to the mass flow controller. The mass flow controller also includes diagnostic software that permits a technician to execute diagnostics through the network interface port.
    Type: Grant
    Filed: June 24, 2002
    Date of Patent: October 26, 2004
    Assignee: MKS Instruments, Inc.
    Inventors: Ali Shajii, Nicholas Kottenstette, Jesse Ambrosina
  • Publication number: 20040187928
    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: Application
    Filed: April 1, 2004
    Publication date: September 30, 2004
    Inventors: Jesse Ambrosina, Nicholas E. Kottenstette, Ali Shajii
  • Publication number: 20040182148
    Abstract: An apparatus for conditioning a gas flow to improve a measurement of rate of pressure change associated with the gas flow includes a measurement chamber having an interior portion characterized by an internal volume, and an inlet port for receiving the gas flow. The apparatus includes a pressure sensor and a signal processor. The signal processor receives and samples the pressure signal from the sensor, and calculates a time derivative of the pressure signal. The apparatus also includes an inlet damper disposed at the inlet port, so that the gas flow passes through the inlet damper prior to passing into the measurement chamber. The inlet damper modifies the gas flow according to a damper transfer function. The chamber volume and the damper transfer function are selected so as to the frequencies associated with variations of the pressure in the measurement chamber to a predetermined fraction of the sampling frequency.
    Type: Application
    Filed: March 19, 2003
    Publication date: September 23, 2004
    Inventors: John A. Smith, Ali Shajii
  • Patent number: 6783630
    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: August 27, 2002
    Date of Patent: August 31, 2004
    Assignee: Axcelis Technologies, Inc.
    Inventors: Ali Shajii, David Tao, Mathias Koch, Douglas Brown, Hossein Zarrin