Patents by Inventor Gaurav Keswani

Gaurav Keswani 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: 20070279608
    Abstract: A lithography apparatus having a fluid confinement plate, which completely submerges the imaging surface of a substrate, is disclosed. The apparatus includes an imaging element defining an image and a stage configured to support the substrate. A projection optical system is provided to project the image defined by the imaging element onto the imaging surface of the substrate. A gap, filled with immersion fluid, is provided between the imaging surface of the substrate and the last optical element of the projection optical system. The fluid confinement plate, which is positioned within the gap between the last optical element and the substrate, is sufficiently sized so that the imaging surface is completely submerged in the immersion fluid. The fluid confinement plate includes a first surface facing the gap and opposing the imaging surface of the substrate. The first surface includes a droplet control element to control the formation of droplets forming on the first surface.
    Type: Application
    Filed: September 20, 2006
    Publication date: December 6, 2007
    Applicant: NIKON CORPORATION
    Inventors: Alex Ka Tim Poon, Leonard Wai Fung Kho, Gaurav Keswani, Derek Coon
  • Publication number: 20070126999
    Abstract: Immersion liquid is contained in the immersion area located between the last optical member of a projection system and a surface that is the subject of exposure by providing a liquid seal located adjacent to the immersion area. The liquid seal extends between the surface to be exposed and a seal-holding-surface located adjacent to the immersion area. The liquid seal is a seal-forming-liquid that is different from the immersion liquid and that is maintained in place between the surface to be exposed and the seal-holding-surface only by surface tension.
    Type: Application
    Filed: November 20, 2006
    Publication date: June 7, 2007
    Applicant: NIKON CORPORATION
    Inventors: Alex Poon, Leonard Kho, Gaurav Keswani
  • Publication number: 20070091289
    Abstract: Immersion fluid remaining on a portion of a substrate after that portion has passed an immersion nozzle is removed by moving the substrate relative to an immersion nozzle so that the portion of the substrate on which the immersion fluid remains is passed by the immersion nozzle again. A path is determined along which the substrate is to be moved to remove the remaining immersion fluid. The path can be determined based upon previous movements of the substrate, including factors such as the speed and/or length of the previous movements. Alternatively, portions of the substrate on which immersion fluid remains can be detected, and then the substrate can be moved so that the portion of the substrate on which the immersion fluid remains is passed by the immersion nozzle based on the results of the detection. Immersion fluid also can be removed from the stage surface located beyond the substrate.
    Type: Application
    Filed: October 19, 2006
    Publication date: April 26, 2007
    Applicant: NIKON CORPORATION
    Inventors: Alex Poon, Leonard Kho, Gaurav Keswani
  • Publication number: 20070046910
    Abstract: A apparatus and methods recover a fluid from an immersion area formed in a gap between a projection system and an object of exposure in an immersion lithography system. A porous member is disposed adjacent to the immersion area. A pressure control system provides a first low pressure to a first portion of the porous member to remove immersion fluid that escapes from the immersion area, and provides a second low pressure to a second portion of the porous member to remove immersion fluid that escapes from the immersion area. The second low pressure is different from the first low pressure.
    Type: Application
    Filed: May 31, 2006
    Publication date: March 1, 2007
    Applicant: NIKON CORPORATION
    Inventors: Alex Poon, Leonard Kho, Gaurav Keswani