Patents by Inventor Tsutomu Mizugaki

Tsutomu Mizugaki 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).

  • Manufacturing method for calcium fluoride and calcium fluoride for photolithography
    Patent number: 6811606
    Abstract: A manufacturing method for a single crystal of calcium fluoride by which it is possible to obtain a single crystal of calcium fluoride with adequately small double refraction, which can be used in optical systems for photolithography, and in particular, a single crystal of calcium fluoride with a large diameter (ø200 mm or larger) having superior optical properties, which can be used for photolithography with a wavelength of 250 nm or less.
    Type: Grant
    Filed: October 22, 2001
    Date of Patent: November 2, 2004
    Assignee: Nikon Corporation
    Inventors: Shigeru Sakuma, Tsutomu Mizugaki, Kazuo Kimura, Shuuichi Takano
  • Manufacturing method for calcium fluoride and calcium fluoride for photolithography
    Publication number: 20020038625
    Abstract: A manufacturing method for a single crystal of calcium fluoride by which it is possible to obtain a single crystal of calcium fluoride with adequately small double refraction, which can be used in optical systems for photolithography, and in particular, a single crystal of calcium fluoride with a large diameter (ø200 mm or larger) having superior optical properties, which can be used for photolithography with a wavelength of 250 nm or less.
    Type: Application
    Filed: October 22, 2001
    Publication date: April 4, 2002
    Applicant: Nikon Corporation
    Inventors: Shigeru Sakuma, Tsutomu Mizugaki, Kazuo Kimura, Shuuichi Takano
  • Manufacturing method for calcium fluoride and calcium fluoride for photolithography
    Patent number: 6332922
    Abstract: A manufacturing method for a single crystal of calcium fluoride by which it is possible to obtain a single crystal of calcium fluoride with adequately small double refraction, which can be used in optical systems for photolithography, and in particular, a single crystal of calcium fluoride with a large diameter (ø 200 mm or larger) having superior optical properties, which can be used for photolithography with a wavelength of 250 nm or less.
    Type: Grant
    Filed: February 25, 1999
    Date of Patent: December 25, 2001
    Assignee: Nikon Corporation
    Inventors: Shigeru Sakuma, Tsutomu Mizugaki, Kazuo Kimura, Shuuichi Takano
  • Method for annealing single crystal fluoride and method for manufacturing the same
    Patent number: 6146456
    Abstract: An annealing method for a single crystal of fluoride is provided. The method includes the steps of removing at least one of attached objects and absorbed objects from the surface of the single crystal of fluoride to clean the surface, thereafter annealing the single crystal of fluoride, including heating the single crystal of fluoride and gradually cooling the heated single crystal of fluoride, and removing a deteriorated layer which is formed on the surface of the single crystal of fluoride during the annealing step.
    Type: Grant
    Filed: August 17, 1998
    Date of Patent: November 14, 2000
    Assignee: Nikon Corporation
    Inventors: Tsutomu Mizugaki, Shuuichi Takano
  • Manufacturing method for calcium fluoride crystal and processing method for calcium fluoride powder
    Patent number: 6123764
    Abstract: A manufacturing method for a single crystal of calcium fluoride includes the steps of degassing calcium fluoride powder particles to desorb impurities from surfaces of the calcium fluoride powder particles, preprocessing the degassed calcium fluoride powder particles by fusing the degassed calcium fluoride powder particles in a crucible to obtain a preprocessed product, and re-fusing the preprocessed product in a crucible to grow a single crystal of calcium fluoride.
    Type: Grant
    Filed: December 1, 1998
    Date of Patent: September 26, 2000
    Assignee: Nikon Corporation
    Inventors: Tsutomu Mizugaki, Kazuo Kimura, Shuuichi Takano
  • Image-focusing optical system for ultraviolet laser
    Patent number: 6061174
    Abstract: An optical member is provided for use in an image-focusing optical system for guiding light having a wavelength shorter than about 300 nm. The optical member includes a calcium fluoride crystal having a sodium concentration of less than about 0.2 ppm.
    Type: Grant
    Filed: March 18, 1998
    Date of Patent: May 9, 2000
    Assignee: Nikon Corporation
    Inventors: Masaki Shiozawa, Tsutomu Mizugaki, Shigeru Sakuma, Norio Komine, Seishi Fujiwara, Hiroki Jinbo
  • Projection exposure apparatus
    Patent number: 5978070
    Abstract: A projection exposure apparatus capable of projecting and exposing mask pattern images onto a substrate by means of a optical projection system, the apparatus includes an optical illumination system capable of illuminating a mask utilizing an excimer laser illuminating light source in a wavelength range of 230 nm or less, and an optical projection system including optical members that include a calcium fluoride crystal with a total alkaline earth metal impurity content of 1.times.10.sup.18 atom/cm.sup.3 or less, and which projects images of the mask pattern onto a substrate. The calcium fluoride crystal is manufactured by a method including the steps of adding a fluorinating agent to a powdered calcium fluoride forming a mixture, placing the mixture in a growing crucible inside a vacuum furnace, and evacuating the vacuum furnace.
    Type: Grant
    Filed: February 19, 1998
    Date of Patent: November 2, 1999
    Assignee: Nikon Corporation
    Inventors: Shigeru Sakuma, Tsutomu Mizugaki, Masaki Shiozawa