Patents by Inventor Vishnu Kamat

Vishnu Kamat 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: 20070160917
    Abstract: Using phase shifting on a mask can advantageously improve printed feature resolution on a wafer, thereby allowing greater feature density on an integrated circuit. Phase shifting can create an intensity imbalance between 0 degree and 180 degree phase shifters on the mask. An improved method of designing an alternating PSM to minimize this intensity imbalance is provided. Sub-resolution features, called “blockers”, can be incorporated in the alternating PSM design. Specifically, blockers can be formed in the 0 degree phase shifters. In this configuration, the intensity associated with the 0 degree phase shifters approximates the intensity associated with the corresponding 180 degree phase shifters. Intensity balancing using blockers retains image contrast, thereby ensuring printed feature quality.
    Type: Application
    Filed: August 4, 2006
    Publication date: July 12, 2007
    Applicant: Synopsys, Inc.
    Inventors: Vishnu Kamat, Armen Kroyan
  • Publication number: 20060075379
    Abstract: A method for modifying instances of a repeating pattern in an integrated circuit design to correct for perturbations during rendering is described. In the typical embodiment, these corrections are optical proximity corrections that correct for optical effects during the projection of the mask pattern onto the wafer and/or processing effects for example photoresist response and etching effects. The method comprises determining a correction for the repeating pattern based on a first set of tolerances for features of the repeating pattern. Then, the suitability of the corrections is evaluated for instances of the repeating pattern in the integrated circuit design based on a second set of tolerances, which is different from the first set of tolerances. This can be used to preserve much of the hierarchy of the layout data in the corrected, or lithography, data. This can be achieved during the OPC process, thus avoiding the post OPC compaction.
    Type: Application
    Filed: September 30, 2004
    Publication date: April 6, 2006
    Applicant: Invarium, Inc.
    Inventor: Vishnu Kamat
  • Publication number: 20060075371
    Abstract: A method and apparatus for partitioning of the input design into repeating patterns called template cores for the application of reticle enhancement methods, design verification for manufacturability and design corrections for optical and process effects is accomplished by hierarchy analysis to extract cell overlap information. Also hierarchy analysis is performed to extract hierarchy statistics. Finally template core candidates are identified. This allows to the design to be made amenable for design corrections or other analyses or modifications that are able to leverage the hierarchy of the design since the cell hierarchy could otherwise be very deep or cells could have significant overlap with each other.
    Type: Application
    Filed: September 30, 2004
    Publication date: April 6, 2006
    Applicant: Invarium, Inc.
    Inventor: Vishnu Kamat
  • Publication number: 20050273734
    Abstract: A method of correction for design data includes the steps of sequentially applying a plurality of corrections to a plurality of features based on a plurality of feature tolerances to design data in a predetermined order, and providing corrected design data.
    Type: Application
    Filed: June 4, 2004
    Publication date: December 8, 2005
    Inventor: Vishnu Kamat
  • Publication number: 20050177809
    Abstract: Using phase shifting on a mask can advantageously improve printed feature resolution on a wafer, thereby allowing greater feature density on an integrated circuit. Phase shifting can create an intensity imbalance between 0 degree and 180 degree phase shifters on the mask. An improved method of designing an alternating PSM to minimize this intensity imbalance is provided. Sub-resolution features, called “blockers”, can be incorporated in the alternating PSM design. Specifically, blockers can be formed in the 0 degree phase shifters. In this configuration, the intensity associated with the 0 degree phase shifters approximates the intensity associated with the corresponding 180 degree phase shifters. Intensity balancing using blockers retains image contrast, thereby ensuring printed feature quality.
    Type: Application
    Filed: February 5, 2004
    Publication date: August 11, 2005
    Inventors: Vishnu Kamat, Armen Kroyan