Patents by Inventor Raman G. Viswanathan

Raman G. Viswanathan 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: 7767385
    Abstract: A method of lithography is disclosed, which allows for independent resist process optimization of two or more exposure steps that are performed on a single resist layer. By providing for a separate post-exposure bake after each resist exposure step, pattern resolution for each exposure can be optimized. The method can generally be used with different lithographic techniques, and is well-suited for hybrid lithography. It has been applied to the fabrication of a device, in which the active area and the gate levels are defined in separate mask levels using hybrid lithography with an e-beam source and a 248 nm source respectively. Conditions for post-exposure bakes after the two exposure steps are independently adjusted to provide for optimized results.
    Type: Grant
    Filed: March 9, 2006
    Date of Patent: August 3, 2010
    Assignee: International Business Machines Corporation
    Inventors: Carl E. Larson, Sharee J. McNab, Steven E. Steen, Raman G. Viswanathan, Gregory M. Wallraff
  • Patent number: 7659050
    Abstract: Non-chemically amplified radiation sensitive resist compositions containing silicon are especially useful for lithographic applications, especially E-beam lithography. More particularly, radiation-sensitive resist compositions comprising a polymer having at least one silicon-containing moiety and at least one radiation-sensitive moiety cleavable upon radiation exposure to form aqueous base soluble moiety can be used to pattern sub-50 nm features with little or no blur.
    Type: Grant
    Filed: June 7, 2005
    Date of Patent: February 9, 2010
    Assignee: International Business Machines Corporation
    Inventors: James J. Bucchignano, Wu-Song S. Huang, David P. Klaus, Lidija Sekaric, Raman G. Viswanathan
  • Publication number: 20070269736
    Abstract: The present invention discloses a resist composition and a method of forming a material structure having a pattern containing features having a dimension of about 40 nm or less by using the inventive resist. The inventive resist comprises a polymer and a photoacid generator. The polymer of the present invention comprises pendant polar moieties, pendant fluoroalcohol moieties, and a backbone containing SiO moieties. In the present invention, at least a portion of the polar moieties are protected with acid labile moieties having a low activation energy. It is preferred that some, but not all, of the pendant fluoroalcohol moieties are protected with acid labile moieties having a low activation energy.
    Type: Application
    Filed: May 16, 2006
    Publication date: November 22, 2007
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: James P. Bucchignano, Wu-Song S. Huang, Lidija Sekaric, Raman G. Viswanathan
  • Patent number: 5051598
    Abstract: A proximity effect correction method for electron beam lithography suitable for high voltages and/or very dense patterns applies both backscatter and forward scatter dose corrections. Backscatter dose corrections are determined by computing two matrices, a "Proximity Matrix" P and a "Fractional Density Matrix" F. The Proximity Matrix P is computed using known algorithms. The elements of the Fractional Density Matrix are the fractional shape coverage in a mesh of square cells which is superimposed on a pattern of interest. Then, a Dose Correction Matrix D is computed by convolving the P and F matrices. The final backscatter dose corrections are assigned to each shape either as area-weighted averages of the D matrix elements for all cells spanned by the shape, or by polynomial or other interpolation of the dose correction field defined by the D matrix. The D matrix also provides a basis for automatic shape fracturing for optimal proximity correction.
    Type: Grant
    Filed: September 12, 1990
    Date of Patent: September 24, 1991
    Assignee: International Business Machines Corporation
    Inventors: Christopher J. Ashton, Porter D. Gerber, Dieter P. Kern, Walter W. Molzen, Jr., Stephen A. Rishton, Michael G. Rosenfield, Raman G. Viswanathan