Patents by Inventor Tomohiro Sakazaki

Tomohiro Sakazaki 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: 8466439
    Abstract: An electron beam lithography apparatus includes a storage for storing data on a drawing pattern assigned a rank based on an accuracy required for a device pattern, a drawing pattern adjustment unit to generate data on divided drawing patterns based on the rank, a settlement wait time adjustment unit to determine a settlement wait time based on the rank, and a controller to draw the device pattern while irradiating an electron beam based on the data on the divided drawing patterns and the settlement wait time. The drawing pattern adjustment unit determines upper limits on the long-side length of a divided drawing pattern or on the area of the divided drawing pattern based on the rank, and divides the drawing pattern based on the upper limits.
    Type: Grant
    Filed: May 25, 2011
    Date of Patent: June 18, 2013
    Assignee: Advantest Corp.
    Inventors: Akio Yamada, Tomohiro Sakazaki, Hiroshi Yasuda
  • Publication number: 20110226967
    Abstract: An electron beam lithography apparatus includes a storage for storing data on a drawing pattern assigned a rank based on an accuracy required for a device pattern, a drawing pattern adjustment unit to generate data on divided drawing patterns based on the rank, a settlement wait time adjustment unit to determine a settlement wait time based on the rank, and a controller to draw the device pattern while irradiating an electron beam based on the data on the divided drawing patterns and the settlement wait time. The drawing pattern adjustment unit determines upper limits on the long-side length of a divided drawing pattern or on the area of the divided drawing pattern based on the rank, and divides the drawing pattern based on the upper limits.
    Type: Application
    Filed: May 25, 2011
    Publication date: September 22, 2011
    Inventors: Akio Yamada, Tomohiro Sakazaki, Hiroshi Yasuda
  • Publication number: 20080049204
    Abstract: A multi-column type electron beam exposure apparatus includes: plural column cells disposed over a wafer, each including an electron gun, deflector for deflecting an electron beam emitted by the electron gun, and exposure data receiving unit for receiving exposure data; and correction computing unit for calculating the exposure data for use in the column cells. The correction computing unit includes exposure data controlling unit and exposure data transmitting unit for each of the column cells. The exposure data transmitting unit encodes the exposure data corrected by the exposure data controlling unit to convert the data into serial data, converts the serial data into a light signal, and transmits the light signal. The exposure data receiving unit converts the light signal into an electric signal, and decodes the encoded exposure data to convert the data into parallel data.
    Type: Application
    Filed: August 30, 2007
    Publication date: February 28, 2008
    Inventors: Hidefumi Yabara, Kenichi Miyazawa, Tomohiro Sakazaki, Kazuaki Tanaka
  • Patent number: 6344655
    Abstract: Disclosed is a multicolumn charged-particle beam lithography system having the circuitry of a settlement wait time control unit thereof simplified. The settlement wait time control unit controls a settlement wait time to be spent by each of amplifiers connected to main deflectors necessary to realize concurrent exposure among columns. The charged-particle beam lithography system has a plurality of columns for patterning an exposed sample by deflecting and sweeping a charged-particle beam on the exposed sample according to expose pattern data. The charged-particle beam lithography system includes a settlement wait time control unit for controlling a settlement wait time to be spent by each of the amplifiers connected to the deflectors necessary to realize concurrent exposure among the columns.
    Type: Grant
    Filed: July 13, 1999
    Date of Patent: February 5, 2002
    Assignee: Advantest Corporation
    Inventors: Tomohiro Sakazaki, Masami Takigawa
  • Publication number: 20010013581
    Abstract: A method of exposing a wafer to a charged-particle beam by directing to the wafer the charged-particle beam deflected by a deflector includes the steps of arranging a plurality of first marks at different heights, focusing the charged-particle beam on each of the first marks by using a focus coil provided above the deflector, obtaining a focus distance for each of the first marks, obtaining deflection-efficiency-correction coefficients for each of the first marks, and using linear functions of the focus distance for approximating the deflection-efficiency-correction coefficients to obtain the deflection-efficiency-correction coefficients for an arbitrary value of the focus distance. A device for carrying out the method is also set forth.
    Type: Application
    Filed: April 6, 2001
    Publication date: August 16, 2001
    Inventors: Akio Takemoto, Yoshihisa Ooaeh, Tomohiko Abe, Hiroshi Yasuda, Takamasa Satoh, Hideki Nasuno, Hidefumi Yabara, Kenichi Kawakami, Kiichi Sakamoto, Tomohiro Sakazaki, Isamu Seto, Masami Takigawa, Tatsuro Ohkawa
  • Patent number: 6242751
    Abstract: A method of exposing a wafer to a charged-particle beam by directing to the wafer the charged-particle beam deflected by a deflector includes the steps of arranging a plurality of first marks at different heights, focusing the charged-particle beam on each of the first marks by using a focus coil provided above the deflector, obtaining a focus distance for each of the first marks, obtaining deflection-efficiency-correction coefficients for each of the first marks, and using linear functions of the focus distance for approximating the deflection-efficiency-correction coefficients to obtain the deflection-efficiency-correction coefficients for an arbitrary value of the focus distance. A device for carrying out the method is also set forth.
    Type: Grant
    Filed: July 15, 1999
    Date of Patent: June 5, 2001
    Assignee: Fujitsu Limited
    Inventors: Akio Takemoto, Yoshihisa Ooaeh, Tomohiko Abe, Hiroshi Yasuda, Takamasa Satoh, Hideki Nasuno, Hidefumi Yabara, Kenichi Kawakami, Kiichi Sakamoto, Tomohiro Sakazaki, Isamu Seto, Masami Takigawa, Tatsuro Ohkawa
  • Patent number: 5969365
    Abstract: A method of exposing a wafer to a charged-particle beam by directing to the wafer the charged-particle beam deflected by a deflector includes the steps of arranging a plurality of first marks at different heights, focusing the charged-particle beam on each of the first marks by using a focus coil provided above the deflector, obtaining a focus distance for each of the first marks, obtaining deflection-efficiency-correction coefficients for each of the first marks, and using linear functions of the focus distance for approximating the deflection-efficiency-correction coefficients to obtain the deflection-efficiency-correction coefficients for an arbitrary value of the focus distance. A device for carrying out the method is also set forth.
    Type: Grant
    Filed: August 26, 1997
    Date of Patent: October 19, 1999
    Assignee: Fujitsu Limited
    Inventors: Akio Takemoto, Yoshihisa Ooaeh, Tomohiko Abe, Hiroshi Yasuda, Takamasa Satoh, Hideki Nasuno, Hidefumi Yabara, Kenichi Kawakami, Kiichi Sakamoto, Tomohiro Sakazaki, Isamu Seto, Masami Takigawa, Tatsuro Ohkawa
  • Patent number: 5757015
    Abstract: A method of exposing a wafer to a charged-particle beam by directing to the wafer the charged-particle beam deflected by a deflector includes the steps of arranging a plurality of first marks at different heights, focusing the charged-particle beam on each of the first marks by using a focus coil provided above the deflector, obtaining a focus distance for each of the first marks, obtaining deflection-efficiency-correction coefficients for each of the first marks, and using linear functions of the focus distance for approximating the deflection-efficiency-correction coefficients to obtain the deflection-efficiency-correction coefficients for an arbitrary value of the focus distance. A device for carrying out the method is also set forth.
    Type: Grant
    Filed: April 18, 1996
    Date of Patent: May 26, 1998
    Assignee: Fujitsu Limited
    Inventors: Akio Takemoto, Yoshihisa Ooaeh, Tomohiko Abe, Hiroshi Yasuda, Takamasa Satoh, Hideki Nasuno, Hidefumi Yabara, Kenichi Kawakami, Kiichi Sakamoto, Tomohiro Sakazaki, Isamu Seto, Masami Takigawa, Tatsuro Ohkawa