Patents by Inventor Seiji Nishizawa

Seiji Nishizawa 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).

  • Apparatus and method for measuring thickness of thin semiconductor multi-layer film
    Patent number: 5587792
    Abstract: An interference waveform dispersion spectrum of light reflected from a multi-layer film is compared to a waveform obtained by numerical calculation using an optical characteristic matrix. Respective layer thickness values obtained from the calculated analysis of the Spatial interference waveform are subjected to waveform fitting with actually measured values. The theoretical interference spectrum is recalculated while changing approximate values of the layer thicknesses until a match is obtained to obtain precise respective layer thicknesses. The thicknesses of respective layers of a thin multi-layer film of submicron thicknesses can be non-destructively measured exactly and stably without direct contact.
    Type: Grant
    Filed: October 11, 1995
    Date of Patent: December 24, 1996
    Inventors: Seiji Nishizawa, Tokuji Takahashi, Ryo Hattori
  • Method and apparatus for measuring the thicknesses of layers of a multiple layer semiconductor film utilizing the comparison between a spatialgram and an optical characteristic matrix
    Patent number: 5523840
    Abstract: An interference waveform dispersion spectrum of light reflected from a multi-layer film is compared to a waveform obtained by numerical calculation using an optical characteristic matrix. Respective layer thickness values obtained from the calculated analysis of the Spatial interference waveform are subjected to waveform fitting with actually measured values. The theoretical interference spectrum is recalculated while changing approximate values of the layer thicknesses until a match is obtained to obtain precise respective layer thicknesses. The thicknesses of respective layers of a thin multi-layer film of submicron thicknesses can be non-destructively measured exactly and stably without direct contact.
    Type: Grant
    Filed: June 21, 1994
    Date of Patent: June 4, 1996
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Seiji Nishizawa, Tokuji Takahashi, Ryo Hattori
  • Apparatus for preparing sample solution for infrared spectrophotometer and method of analyzing sample solution
    Patent number: 4841145
    Abstract: A method of analyzing a sample solution comprises the steps of allowing the sample solution to drip onto a sample retaining means, depositing a solute of the sample solution by evaporating a solvent thereof, irradiating infrared radiation onto this solute, and measuring the intensity of the infrared radiation which is reflected by the solute and the sample retaining means disposed under the solute so as to obtained an infrared spectrum. An apparatus for preparing a sample solution is provided for carrying out the above-described method. In this apparatus, the sample retaining means is moved so that a layer of solute which corresponds to each droplet of sample solution is continuously formed on the sample retaining means.
    Type: Grant
    Filed: June 18, 1987
    Date of Patent: June 20, 1989
    Assignee: Nihon Bunko Kogyo Kabushiki Kaisha
    Inventors: Akio Wada, Fumiko Nakeuchi, Seiji Nishizawa