Patents by Inventor Ahmad Kermani

Ahmad Kermani 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: 5976261
    Abstract: A method and apparatus for multi-zone injection apparatus of multiple process gases onto a work piece during manufacture. The multi-zone injection apparatus uses a gas injection plate with multiple injection zones to deliver the multiple process gases into the chamber for deposition onto the work piece (for example, a silicon wafer). The gas showerhead separates the multiple process in a manner that avoids premixing the process gases, thereby minimizing gas-phase nucleation and particulate generation. The showerhead also allows real-time independent control over the gas flow rates in N channels to achieve deposition uniformity. Different gases can be configured in adjacent channels to provide M zones of multi-gas radial control.
    Type: Grant
    Filed: July 11, 1996
    Date of Patent: November 2, 1999
    Assignee: CVC Products, Inc.
    Inventors: Mehrdad M. Moslehi, Yong Jin Lee, Ahmad Kermani
  • Patent number: 5937142
    Abstract: A system for rapid thermal processing of a substrate in a process chamber while measuring and controlling the temperature at the substrate to establish substantially uniform substrate temperature in real time. The system includes an axisymmetrical multi-zone illuminator having a plurality of substantially concentric rings of heating lamps to direct optical power toward said substrate, a fluid cooled optical reflector facing the substrate frontside and having a relatively high optical reflectivity. The system also includes a multizone temperature measurement system having a plurality of pyrometry sensors coupled to said multi-zone illuminator, a system for real-time measurement and compensation of substrate emissivity and illuminator lamp light interference effects, and a multi-variable temperature controller for providing multi-zone real-time temperature control. The system also incorpotates a plurality of illuminator lamp power supplies.
    Type: Grant
    Filed: July 11, 1996
    Date of Patent: August 10, 1999
    Assignee: CVC Products, Inc.
    Inventors: Mehrdad M. Moslehi, Yong Jin Lee, Ahmad Kermani, William J. Messner
  • Patent number: 5324684
    Abstract: A technique for doping silicon material or other semiconductors uses gas phase dopant sources under reduced pressure in a radiantly heated, cold-wall reactor. The technique is applied to the automated integrated circuit manufacturing techniques being adopted in modern fabrication facilities. The method includes placing a substrate comprising semiconductor material on a thermally isolated support structure in a reduced pressure, cold-wall reaction chamber; radiantly heating the substrate within the reaction chamber to a controlled temperature; flowing a gas phase source of dopant at controlled pressure and concentration in contact with the substrate so that the dopant is absorbed by the substrate, and annealing the substrate. The substrate may be first coated with a layer of polycrystalline semiconductor, and then gas phase doping as described above may be applied to the polycrystalline layer.
    Type: Grant
    Filed: February 25, 1992
    Date of Patent: June 28, 1994
    Assignee: AG Processing Technologies, Inc.
    Inventors: Ahmad Kermani, Kristian E. Johnsgard, Carl Galewski
  • Patent number: 5002630
    Abstract: A method for inducing a reaction in a reaction chamber of a reactive carrier having a first specific heat, on a reaction surface of a substrate. The method comprises the steps of supporting the substrate in the reaction chamber. Next, the substrate is heated to a reaction temperature, so that the reaction surface has an essentially balanced temperature distribution. The reactive carrier is mixed with an inert gas having a second specific heat to form a reaction mixture, wherein the second specific heat is lower than the first specific heat. Finally, the reaction mixture is supplied into the chamber so that it flows over the surface of the substrate. Because the inert gas has a lower specific heat than the carrier, the overall specific heat of the reaction mixture is reduced. With a lower specific heat, less heat is transferred from the wafer into the reaction mixture. This reduces convective heat loss and thermal gradients in the substrate.
    Type: Grant
    Filed: June 6, 1989
    Date of Patent: March 26, 1991
    Assignee: Rapro Technology
    Inventors: Ahmad Kermani, Mike F. Robertson, Yen-Hui Ku, Fred Wong
  • Patent number: 4984902
    Abstract: The present invention is an apparatus for calibrating a temperature feedback value in a water processing chamber to automatically compensate for variations in infrared emissions from a heated semiconductor wafer due to variations in composition and coatings from wafer to wafer. A calibration wafer with an imbedded thermocouple is used to generate a table relating actual wafer temperatures to power supplied to the heating chamber and infrared emissions detected by a pyrometer. A sample wafer of a batch to be processed is subsequently placed in the chamber at a known power level, and any difference between the detected infrared emission value and the value in the table is used to adjust the entire table according to a first predetermined formula or table. Before each wafer is processed, a known source of infrared light is reflected off the wafer and detected. The reflected light value is compared to a reflection measurement for the sample wafer.
    Type: Grant
    Filed: April 17, 1990
    Date of Patent: January 15, 1991
    Assignee: Peak Systems, Inc.
    Inventors: John L. Crowley, Ahmad Kermani, Stephan E. Lassig, Noel H. Johnson, Gary R. Rickords
  • Patent number: 4969748
    Abstract: The present invention is a method and apparatus for calibrating a temperature feedback value in a wafer processing chamber to automatically compensate for variations in infrared emissions from a heated semiconductor wafer due to variations in composition and coatings from wafer to wafer. A calibration wafer with an imbedded thermocouple is used to generate a table relating actual wafer temperatures to power supplied to the heating chamber and infrared emissions detected by a pyrometer. A sample wafer of a batch to be processed is subsequently placed in the chamber at a known power level, and any difference between the detected infrared emission value and the value in the table is used to adjust the entire table according to a first predetermined formula or table. Before each wafer is processed, a known source of infrared light is reflected off the wafer and detected. The reflected light value is compared to a reflection measurement for the sample wafer.
    Type: Grant
    Filed: April 13, 1989
    Date of Patent: November 13, 1990
    Assignee: Peak Systems, Inc.
    Inventors: John L. Crowley, Ahmad Kermani, Stephan E. Lassig, Noel H. Johnson, Gary R. Rickords
  • Patent number: 4755654
    Abstract: A semiconductor wafer heating chamber has an optical element between a light source and a wafer for redistributing the light from the light source. The optical element is constructed in such a manner as to produce the desired illumination (and thus heating) pattern on the semiconductor wafer from the light source. Preferably, the light source is a long-arc lamp mounted above a base plate of a heating chamber. A primary reflector is mounted above the long-arc lamp and is shaped to produce a substantially uniform light distribution on the base plate. A quartz window is mounted between the arc lamp and the base plate. The quartz window acts as a lens to redistribute the light from the lamp and the reflector on a wafer. The window can be constructed as a diffraction grating with a series of lines formed by etching into the window or depositing material on the window to produce a diffraction pattern which gives the desired illumination pattern on the wafer.
    Type: Grant
    Filed: March 26, 1987
    Date of Patent: July 5, 1988
    Inventors: John L. Crowley, Thomas J. DeBolski, Ahmad Kermani, Stephan E. Lassig