Patents by Inventor Daniel G. Stearns

Daniel G. Stearns 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: 20020122989
    Abstract: Absorber material used in conventional EUVL reticles is eliminated by introducing a direct modulation in the complex-valued reflectance of the multilayer. A spatially localized energy source such as a focused electron or ion beam directly writes a reticle pattern onto the reflective multilayer coating. Interdiffusion is activated within the film by an energy source that causes the multilayer period to contract in the exposed regions. The contraction is accurately determined by the energy dose. A controllable variation in the phase and amplitude of the reflected field in the reticle plane is produced by the spatial modulation of the multilayer period. This method for patterning an EUVL reticle has the advantages of (1) avoiding the process steps associated with depositing and patterning an absorber layer and (2) providing control of the phase and amplitude of the reflected field with high spatial resolution.
    Type: Application
    Filed: December 28, 2000
    Publication date: September 5, 2002
    Inventors: Daniel G. Stearns, Donald W. Sweeney, Paul B. Mirkarimi
  • Patent number: 6319635
    Abstract: A multilayer film is used as a buffer layer to minimize the size of defects on a reticle substrate prior to deposition of a reflective coating on the substrate. The multilayer buffer layer deposited intermediate the reticle substrate and the reflective coating produces a smoothing of small particles and other defects on the reticle substrate. The reduction in defect size is controlled by surface relaxation during the buffer layer growth process and by the degree of intermixing and volume contraction of the materials at the multilayer interfaces. The buffer layers are deposited at near-normal incidence via a low particulate ion beam sputtering process. The growth surface of the buffer layer may also be heated by a secondary ion source to increase the degree of intermixing and improve the mitigation of defects.
    Type: Grant
    Filed: December 6, 1999
    Date of Patent: November 20, 2001
    Assignee: The Regents of the University of California
    Inventors: Paul B. Mirkarimi, Sasa Bajt, Daniel G. Stearns
  • Patent number: 6002553
    Abstract: A magnetoresistive sensor element with a three-dimensional micro-architecture is capable of significantly improved sensitivity and highly localized measurement of magnetic fields. The sensor is formed of a multilayer film of alternately magnetic and nonmagnetic materials. The sensor is optimally operated in a current perpendicular to plane mode. The sensor is useful in magnetic read/write heads, for high density magnetic information storage and retrieval.
    Type: Grant
    Filed: February 28, 1994
    Date of Patent: December 14, 1999
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Daniel G. Stearns, Stephen P. Vernon, Natale M. Ceglio, Andrew M. Hawryluk
  • Patent number: 5958605
    Abstract: A passivating overcoat bilayer is used for multilayer reflective coatings for extreme ultraviolet (EUV) or soft x-ray applications to prevent oxidation and corrosion of the multilayer coating, thereby improving the EUV optical performance. The overcoat bilayer comprises a layer of silicon or beryllium underneath at least one top layer of an elemental or a compound material that resists oxidation and corrosion. Materials for the top layer include carbon, palladium, carbides, borides, nitrides, and oxides. The thicknesses of the two layers that make up the overcoat bilayer are optimized to produce the highest reflectance at the wavelength range of operation. Protective overcoat systems comprising three or more layers are also possible.
    Type: Grant
    Filed: November 10, 1997
    Date of Patent: September 28, 1999
    Assignee: Regents of the University of California
    Inventors: Claude Montcalm, Daniel G. Stearns, Stephen P. Vernon
  • Patent number: 5698113
    Abstract: Mo/Si multilayers are removed from superpolished ZERODUR and fused silica substrates with a dry etching process that, under suitable processing conditions, produces negligible change in either the substrate surface figure or surface roughness. The two step dry etching process removes SiO.sub.2 overlayer with a fluroine-containing gas and then moves molybdenum and silicon multilayers with a chlorine-containing gas. Full recovery of the initial normal incidence extreme ultra-violet (EUV) reflectance response has been demonstrated on reprocessed substrates.
    Type: Grant
    Filed: February 22, 1996
    Date of Patent: December 16, 1997
    Assignee: The Regents of the University of California
    Inventors: Sherry L. Baker, Stephen P. Vernon, Daniel G. Stearns