Patents by Inventor Guarav Keswani

Guarav 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).

  • Patent number: 8068209
    Abstract: An immersion lithography tool with a diverter element, positioned between the immersion element and the substrate, for altering the “footprint” or shape of the meniscus of the body of immersion liquid between the last optical element and an immersion element on one side, and the substrate on the other side when the substrate is moved. The apparatus includes a substrate holder to hold the substrate having an imaging surface and a projection optical system having a last optical element. The projection optical system projects an image onto a target imaging area on the substrate through the immersion liquid filled in a gap between the imaging surface of the substrate and the last optical element. An immersion element maintains the immersion fluid in the gap. The diverter element is positioned between the immersion element and the substrate.
    Type: Grant
    Filed: March 10, 2008
    Date of Patent: November 29, 2011
    Assignee: Nikon Corporation
    Inventors: Alex Ka Tim Poon, Leonard Wai Fung Kho, Guarav Keswani, Derek Coon