Patents by Inventor Seima Kato

Seima Kato 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: 20100165355
    Abstract: A refractive index distribution measurement method includes the steps of measuring a first transmission wavefront of a test object by introducing reference light to the test object immersed in a first medium having a first refractive index lower than that of the test object by 0.01 or more, measuring a second transmission wavefront of the test object by introducing the reference light to the test object immersed in a second medium having a second refractive index lower than that of the test object by 0.01 or more and different from the first refractive index, and obtaining a refractive index distribution of the test object based on a measurement result of the first transmission wavefront and a measurement result of the second transmission wavefront.
    Type: Application
    Filed: December 22, 2009
    Publication date: July 1, 2010
    Applicant: CANON KABUSHIKI KAISHA
    Inventor: Seima Kato
  • Patent number: 7692799
    Abstract: The invention provides a measurement apparatus which measures a wavefront aberration of an optical system to be measured, the apparatus includes a measurement mask which is inserted on an object plane of the optical system to be measured, and includes a plurality of reflection units configured to generate spherical waves by reflecting light, the measurement mask including a reflection layer configured to reflect the light, a first layer which is stacked on the reflection layer, has a plurality of openings, and is made of a first substance, and a second layer which is stacked on the first layer, has a window configured to expose a region in which the plurality of openings are arrayed, and is made of a second substance different from the first substance, wherein the plurality of reflection units are formed by portions of the reflection layer, which are exposed through the plurality of openings.
    Type: Grant
    Filed: January 28, 2008
    Date of Patent: April 6, 2010
    Assignee: Canon Kabushiki Kaisha
    Inventor: Seima Kato
  • Publication number: 20090290136
    Abstract: A measuring apparatus includes a pinhole mask, located at an object plane of an optical system to be measured, and having a plurality of pinholes for generating a spherical wave from a measuring light beam, and a diffraction grating for splitting the measuring light beam that has passed the pinhole mask and the optical system, wherein Lg=m·Pg2/? is met, where Pg is a grating pitch of the diffraction grating, ? is a wavelength of the measuring light beam, m is an integer other than zero, and Lg is a distance between the diffraction grating and an image plane of the optical system. The measuring apparatus calculates a wavefront aberration of the optical system from an interferogram formed by causing interference of the measuring light beams split by the diffraction grating.
    Type: Application
    Filed: April 24, 2006
    Publication date: November 26, 2009
    Applicant: Canon Kabushiki Kaisha
    Inventors: Chidane Ouchi, Akihiro Nakauchi, Seima Kato
  • Publication number: 20090268188
    Abstract: An exposure apparatus includes an illumination optical system. The illumination optical system includes a first member configured to define an illuminated region of a reflective mask having a pattern to be projected onto a substrate; a second member configured to define an illuminated region in which a measurement pattern used in measuring wavefront aberration of a projection optical system is illuminated, the second member being able to be inserted into and removed from an optical path of the illumination optical system; and a condensing mirror configured to condense light from the first member on the pattern to be projected onto the substrate and light from the second member on the measurement pattern. The illuminated region defined by the second member is smaller than the illuminated region defined by the first member.
    Type: Application
    Filed: April 6, 2009
    Publication date: October 29, 2009
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Seima Kato, Chidane Ouchi
  • Publication number: 20090213389
    Abstract: A wavefront aberration measuring device includes a mask placed in an object plane of a to-be-tested optical system and having a pattern including a pinhole producing a spherical wave and adjoining diffraction gratings each ruled with lines oriented in a direction different from the other; an illumination optical system that illuminates an area of the mask with light emitted from a light source; a light splitter that splits the light from the pattern transmitted through the to-be-tested optical system; an image pickup unit that takes an image of interference fringes produced by the split light, the image being used in measuring wavefront aberration of the to-be-tested optical system; a detector that detects respective light quantities of respective diffracted beams from the respective illuminated diffraction gratings; and a control unit that controls alignment of the illuminated area of the mask and the pattern in accordance with a detection result.
    Type: Application
    Filed: February 24, 2009
    Publication date: August 27, 2009
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Chidane Ouchi, Masanobu Hasegawa, Seima Kato
  • Patent number: 7474413
    Abstract: Disclosed is a method of analyzing an interference fringe, with which method the optical characteristics of an optical system to be examined can be analyzed very precisely. In one preferred form of the invention, the analyzing method includes a step of detecting information related to a first interference fringe produced by interference of two light fluxes, a step of detecting information related to a second interference fringe produced while changing a phase of one of the two light fluxes by ? as multiplied by an odd number (e.g., 1?, 3?, . . . ), and a step of detecting averaged information of phase information of the two interference fringes, on the basis of the detected information of the first and second interference fringes and by use of Fourier transform.
    Type: Grant
    Filed: February 27, 2006
    Date of Patent: January 6, 2009
    Assignee: Canon Kabushiki Kaisha
    Inventor: Seima Kato
  • Patent number: 7443515
    Abstract: A measuring apparatus for measuring the optical properties of an optical system including a mask with a slit and a window, upon which different light beams are focused to derive an interference pattern. The interference pattern can be used to obtain optical properties of the optical system.
    Type: Grant
    Filed: August 15, 2005
    Date of Patent: October 28, 2008
    Assignee: Canon Kabushiki Kaisha
    Inventor: Seima Kato
  • Publication number: 20080186509
    Abstract: The invention provides a measurement apparatus which measures a wavefront aberration of an optical system to be measured, the apparatus includes a measurement mask which is inserted on an object plane of the optical system to be measured, and includes a plurality of reflection units configured to generate spherical waves by reflecting light, the measurement mask including a reflection layer configured to reflect the light, a first layer which is stacked on the reflection layer, has a plurality of openings, and is made of a first substance, and a second layer which is stacked on the first layer, has a window configured to expose a region in which the plurality of openings are arrayed, and is made of a second substance different from the first substance, wherein the plurality of reflection units are formed by portions of the reflection layer, which are exposed through the plurality of openings.
    Type: Application
    Filed: January 28, 2008
    Publication date: August 7, 2008
    Applicant: CANON KABUSHIKI KAISHA
    Inventor: Seima Kato
  • Patent number: 7283252
    Abstract: A measuring method for measuring an interference fringe includes the steps of generating a reference wave as a result of transmission through a slit or pinhole in a mask of a portion of light that has passed a target optical system, generating the interference fringe between the reference wave and a wave of another portion of light that has passed the target optical system and contains aberration information of the target optical system, determining whether contrast of the interference fringe is higher than a predetermined threshold, and exchanging the pinhole or the slit when the contrast is below the predetermined threshold.
    Type: Grant
    Filed: November 26, 2004
    Date of Patent: October 16, 2007
    Assignee: Canon Kabushiki Kaisha
    Inventor: Seima Kato
  • Publication number: 20060203253
    Abstract: Disclosed is a method of analyzing an interference fringe, with which method the optical characteristics of an optical system to be examined can be analyzed very precisely. In one preferred form of the invention, the analyzing method includes a step of detecting information related to a first interference fringe produced by interference of two light fluxes, a step of detecting information related to a second interference fringe produced while changing a phase of one of the two light fluxes by ? as multiplied by an odd number (e.g., 1 ?, 3 ?, . . . ), and a step of detecting averaged information of phase information of the two interference fringes, on the basis of the detected information of the first and second interference fringes and by use of Fourier transform.
    Type: Application
    Filed: February 27, 2006
    Publication date: September 14, 2006
    Inventor: Seima Kato
  • Publication number: 20060072091
    Abstract: An exposure apparatus includes plural light modulators that are arranged in parallel, each of which includes an element for modulating a phase distribution of incident light by providing the incident light with a phase difference, and plural projection optical systems that are arranged in parallel, each of which corresponds to each light modulator and projects a pattern formed by a corresponding one of the light modulators onto an object to be exposed.
    Type: Application
    Filed: September 29, 2005
    Publication date: April 6, 2006
    Inventor: Seima Kato
  • Publication number: 20060044569
    Abstract: A measuring apparatus for measuring the optical properties of an optical system including a mask with a slit and a window, upon which different light beams are focused to derive an interference pattern. The interference pattern can be used to obtain optical properties of the optical system.
    Type: Application
    Filed: August 15, 2005
    Publication date: March 2, 2006
    Applicant: Canon Kabushiki Kaisha
    Inventor: Seima Kato
  • Publication number: 20050117171
    Abstract: A measuring method for measuring an interference fringe includes the steps of generating the interference fringe between light that has passed a target optical system, and a reference wave that is generated from part of the light that has passed a mask, determining whether contrast of the interference fringe is higher than a predetermined threshold, and changing a condition of generating the reference wave when the contrast is below the predetermined threshold.
    Type: Application
    Filed: November 26, 2004
    Publication date: June 2, 2005
    Applicant: CANON KABUSHIKI KAISHA
    Inventor: Seima Kato