Patents by Inventor Kaihan Ashtiani

Kaihan Ashtiani 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: 20040202786
    Abstract: Methods and apparatus for preparing a low-resistivity tungsten film on a substrate are provided. Methods involve the formation of a tungsten nucleation layer on a substrate using pulsed nucleation layer (PNL) techniques and depositing a bulk tungsten layer thereon. Methods for forming the tungsten nucleation layer involve the use of a boron-containing species, a tungsten-containing precursor, and optionally, a silane. The methods described are particularly useful for applications where thin, low resistivity films are desired, such as interconnect applications.
    Type: Application
    Filed: March 31, 2004
    Publication date: October 14, 2004
    Applicant: Novellus Systems, Inc.
    Inventors: Panya Wongsenakhum, Aaron R. Fellis, Kaihan A. Ashtiani, Karl B. Levy, Juwen Gao, Joshua Collins, Junghwan Sung, Lana Hiului Chan
  • Publication number: 20040142557
    Abstract: Methods for depositing a tungsten nitride layer are described. The methods form a tungsten nitride layer using a carefully controlled deposition technique such as pulsed nucleation layer (PNL). Initially, a tungsten layer is formed on a substrate surface. The tungsten layer is then exposed to a nitriding agent to form a tungsten nitride layer. Methods of forming relatively thick layers of involve repeated cycles of contact with reducing agent, tungsten precursor and nitriding agent. In some cases, the cycle may also include contact with a dopant precursor such as phosphine or arsine.
    Type: Application
    Filed: October 20, 2003
    Publication date: July 22, 2004
    Applicant: Novellus Systems, Inc.
    Inventors: Karl B. Levy, Junghwan Sung, Kaihan A. Ashtiani, James A. Fair, Joshua Collins, Juwen Gao
  • Patent number: 6541371
    Abstract: A method of depositing thin films comprising tantalum, tantalum nitride, and copper for barrier films and seed layers within high aspect ratio openings used for copper interconnects. The barrier films and seed layers are deposited at extremely low temperature conditions wherein the wafer stage temperature of the sputter source is chilled to about −70° C. to about 0° C. Most preferably, the present invention is practiced using a hollow cathode magnetron. The resulting tantalum and/or tantalum nitride barrier films and copper seed layers are superior in surface smoothness, grain size and uniformity such that subsequent filling of the high aspect ratio opening is substantially void-free.
    Type: Grant
    Filed: January 26, 2000
    Date of Patent: April 1, 2003
    Assignee: Novellus Systems, Inc.
    Inventors: Kaihan A. Ashtiani, Maximilian A. Biberger, Erich R. Klawuhn, Kwok Fai Lai, Karl B. Levy, J. Patrick Rymer
  • Patent number: 6500321
    Abstract: An apparatus and method for controlling and optimizing a non-planar target shape of a sputtering magnetron system are employed to minimize the redeposition of the sputtered material and optimize target erosion. The methodology is based on the integration of sputtered material from each point of the target according to its solid angle view of the rest of the target. The prospective target's geometry is optimized by analytically comparing and evaluating the methodology's results of one target geometry against that of another geometry, or by simply altering the first geometry and recalculating and comparing the results of the first geometry against the altered geometry. The target geometries may be of many different shapes including trapezoidal, cylindrical, parabolic, and elliptical, depending upon the optimum process parameters desired.
    Type: Grant
    Filed: March 2, 2000
    Date of Patent: December 31, 2002
    Assignee: Novellus Systems, Inc.
    Inventors: Kaihan A. Ashtiani, Larry D. Hartsough, Richard S. Hill, Karl B. Levy, Robert M. Martinson
  • Patent number: 6497796
    Abstract: A magnetron source comprises a hollow cathode with a non-planar target. By using a magnet between the cathode and a substrate, plasma can be controlled to achieve high ionization levels, good step coverage, and good process uniformity. Step coverage uniformity is also improved by controlling the magnetic fields, and thus the flow of ions and electrons, near the plane of the substrate.
    Type: Grant
    Filed: August 31, 2000
    Date of Patent: December 24, 2002
    Assignee: Novellus Systems, Inc.
    Inventors: Kaihan A. Ashtiani, Karl B. Levy, Kwok F. Lai, Andrew L. Nordquist, Larry D. Hartsough
  • Patent number: 6444105
    Abstract: A novel hollow cathode magnetron source is disclosed. The source comprises a hollow cathode with a non-planar target. By using a magnet between the cathode and a substrate, plasma can be controlled to achieve high ionization levels, good step coverage, and good process uniformity.
    Type: Grant
    Filed: October 12, 2000
    Date of Patent: September 3, 2002
    Assignee: Novellus Systems, Inc.
    Inventors: Kwok F. Lai, Andrew L. Nordquist, Kaihan A. Ashtiani, Larry D. Hartsough, Karl B. Levy
  • Patent number: 6342133
    Abstract: Ti and TiN layers are formed on an integrated circuit substrate using a titanium target in non-nitrided mode in a hollow cathode magnetron apparatus. Neither a collimator nor a shield is used. Ti and TiN layers are deposited in vias and trenches having aspect ratios up to 5:1.
    Type: Grant
    Filed: March 14, 2000
    Date of Patent: January 29, 2002
  • Publication number: 20010030125
    Abstract: Ti and TiN layers are formed on an integrated circuit substrate using a titanium target in non-nitrided mode in a hollow cathode magnetron apparatus. Neither a collimator nor a shield is used. Ti and TiN layers are deposited in vias and trenches having aspect ratios up to 5:1.
    Type: Application
    Filed: March 14, 2000
    Publication date: October 18, 2001
  • Patent number: 6179973
    Abstract: A novel hollow cathode magnetron source is disclosed. The source comprises a hollow cathode with a non-planar target. By using a magnet between the cathode and a substrate, plasma can be controlled to achieve high ionization levels, good step coverage, and good process uniformity.
    Type: Grant
    Filed: June 30, 1999
    Date of Patent: January 30, 2001
    Assignee: Novellus Systems, Inc.
    Inventors: Kwok F. Lai, Andrew L. Nordquist, Kaihan A. Ashtiani, Larry D. Hartsough, Karl B. Levy