Patents by Inventor Kiichi Sakamoto

Kiichi Sakamoto 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: 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: 6222195
    Abstract: A method of detecting deficiency of an aperture used in a charged-particle-beam exposure process employing at least two exposure columns is disclosed, where each of the two exposure columns passes a charged-particle beam through the aperture formed through a mask to shape a cross section of the charged-particle beam before exposing the charged-particle beam onto an object. The method includes the steps of mounting masks having the same aperture to the at least two exposure columns; scanning, in each of the at least two exposure columns, the charged-particle beam over an area containing a mark on a surface substantially at the same height as the object after passing the charged-particle beam through the same aperture; obtaining, in each of the at least two exposure columns, a signal waveform corresponding to the scan by detecting charged particles scattered by the mark; and comparing the signal waveform between the at least two exposure columns.
    Type: Grant
    Filed: August 11, 2000
    Date of Patent: April 24, 2001
    Assignee: Fujitsu Limited
    Inventors: Akio Yamada, Satoru Sagou, Hitoshi Watanabe, Satoru Yamazaki, Kiichi Sakamoto, Manabu Ohno, Kenichi Kawakami, Katsuhiko Kobayashi
  • Patent number: 6137111
    Abstract: A method of detecting deficiency of an aperture used in a charged-particle-beam exposure process employing at least two exposure columns is disclosed, where each of the two exposure columns passes a charged-particle beam through the aperture formed through a mask to shape a cross section of the charged-particle beam before exposing the charged-particle beam onto an object. The method includes the steps of mounting masks having the same aperture to the at least two exposure columns; scanning, in each of the at least two exposure columns, the charged-particle beam over an area containing a mark on a surface substantially at the same height as the object after passing the charged-particle beam through the same aperture; obtaining, in each of the at least two exposure columns, a signal waveform corresponding to the scan by detecting charged particles scattered by the mark; and comparing the signal waveform between the at least two exposure columns.
    Type: Grant
    Filed: May 28, 1998
    Date of Patent: October 24, 2000
    Assignee: Fujitsu Limited
    Inventors: Akio Yamada, Satoru Sagou, Hitoshi Watanabe, Satoru Yamazaki, Kiichi Sakamoto, Manabu Ohno, Kenichi Kawakami, Katsuhiko Kobayashi
  • Patent number: 6090527
    Abstract: In an exposure mask of the present invention, a plurality of opening regions are disposed via crossbeams, each having a size not to be resolved, along peripheral edges of island-like patterns and peninsula-like patterns for shielding transmission of charged particles.
    Type: Grant
    Filed: June 1, 1998
    Date of Patent: July 18, 2000
    Assignee: Fujitsu Limited
    Inventors: Satoru Yamazaki, Kiichi Sakamoto, Hiroshi Yasuda, Takayuki Sakakibara, Satoru Sagoh
  • Patent number: 6087048
    Abstract: Disclosed is a method of producing a block mask, which is employed in an electron-beam lithography apparatus, with high precision irrespective of the size of openings. The electron-beam lithography apparatus is of a type that produces a unit pattern at a time by transmitting an electron beam through openings selected from among a plurality of kinds of openings of a block mask, links the unit pattern with a previous one, and repeats this process to delineate a desired pattern. The method consists of four steps. At the first step, a resist is applied to the surface of a substrate of a block mask. At the next step, the resist is exposed to delineate patterns of a plurality of kinds of openings. At the next step, the exposed resist is developed. At the next step, the substrate of the block mask is etched.
    Type: Grant
    Filed: February 24, 1999
    Date of Patent: July 11, 2000
    Assignee: Advantest Corporation
    Inventors: Yoshio Suzaki, Takayuki Sakakibara, Kiichi Sakamoto
  • 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: 5965895
    Abstract: A method for providing charged particle beam exposure onto an object having a plurality of chip areas with a plurality of aligning marks formed in correspondence to each of said chip areas. A charged particle beam is irradiated upon an object mounted on a mobile step based upon positions of the aligning marks. Actual positions of the alignment marks are detected and compared to the design positions of the alignment marks to determine approximate relationships which are used to calculate an actual position to perform exposure.
    Type: Grant
    Filed: November 4, 1997
    Date of Patent: October 12, 1999
    Assignee: Fujitsu Limited
    Inventors: Takamasa Satoh, Hiroshi Yasuda, Junichi Kai, Yoshihisa Oae, Hisayasu Nishino, Kiichi Sakamoto, Hidefumi Yabara, Isamu Seto, Masami Takigawa, Akio Yamada, Soichiro Arai, Tomohiko Abe, Takashi Kiuchi, Kenichi Miyazawa
  • Patent number: 5952155
    Abstract: A device exposing an object to an electron beam employs a mask formed of a plate of material which blocks the electron beam and which has plural pattern exposure blocks defined therein, each having one or more aperture defining regions therein and, when selected, determining the shaping of the electron beam passing therethrough so as to expose a respective pattern on an object. Each aperture-defining region has a respective single aperture or respective plural, spaced apertures formed therein and having a total area size selected to be smaller than the area size of the aperture defining region, in accordance with controlling the current level of an electron beam passing therethrough, while reducing Coulomb interaction of the electron beam passing through the aperture or apertures of each aperture defining portion of the pattern exposure block.
    Type: Grant
    Filed: July 21, 1998
    Date of Patent: September 14, 1999
    Assignee: Fujitsu Limited
    Inventors: Takayuki Sakakibara, Satoru Sagoh, Satoru Yamazaki, Kiichi Sakamoto, Hiroshi Yasuda
  • Patent number: 5849437
    Abstract: In an exposure mask of the present invention, a plurality of opening regions are disposed via crossbeams, each having a size not to be resolved, along peripheral edges of island-like patterns and peninsula-like patterns for shielding transmission of charged particles.
    Type: Grant
    Filed: January 24, 1996
    Date of Patent: December 15, 1998
    Assignee: Fujitsu Limited
    Inventors: Satoru Yamazaki, Kiichi Sakamoto, Hiroshi Yasuda, Takayuki Sakakibara, Satoru Sagoh
  • Patent number: 5830612
    Abstract: A method of detecting deficiency of an aperture used in a charged-particle-beam exposure process employing at least two exposure columns is disclosed, where each of the two exposure columns passes a charged-particle beam through the aperture formed through a mask to shape a cross section of the charged-particle beam before exposing the charged-particle beam onto an object. The method includes the steps of mounting masks having the same aperture to the at least two exposure columns; scanning, in each of the at least two exposure columns, the charged-particle beam over an area containing a mark on a surface substantially at the same height as the object after passing the charged-particle beam through the same aperture; obtaining, in each of the at least two exposure columns, a signal waveform corresponding to the scan by detecting charged particles scattered by the mark; and comparing the signal waveform between the at least two exposure columns.
    Type: Grant
    Filed: September 11, 1996
    Date of Patent: November 3, 1998
    Assignee: Fujitsu Limited
    Inventors: Akio Yamada, Satoru Sagou, Hitoshi Watanabe, Satoru Yamazaki, Kiichi Sakamoto, Manabu Ohno, Kenichi Kawakami, Katsuhiko Kobayashi
  • Patent number: 5824437
    Abstract: A mask for exposure of an object by an electron beam is formed of a plate of material which blocks the electron beam and which has plural pattern exposure blocks defined therein, each having one or more aperture defining regions therein and, when selected, determining the shaping of the electron beam passing therethrough so as to expose a respective pattern on an object. Each aperture-defining region has one aperture or plural, spaced apertures formed respectively therein, having a total area size, selected to be smaller than the area size of the aperture defining region in accordance with controlling the current level of an electron beam passing therethrough, while reducing Coulomb interaction of the electron beam passing through the aperture or apertures of each aperture defining portion of the pattern exposure block.
    Type: Grant
    Filed: July 22, 1996
    Date of Patent: October 20, 1998
    Assignee: Fujitsu Limited
    Inventors: Takayuki Sakakibara, Satoru Sagoh, Satoru Yamazaki, Kiichi Sakamoto, Hiroshi Yasuda
  • 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
  • Patent number: 5721432
    Abstract: To improve in the throughput of an exposure system, the setting time during a step change in the output of an amplifier is reduced by switching resistance between the amplifier and deflector, a glitch waveform generated during a step change in the output of a D/A converter at the preceding stage of the amplifier, is anticipated and is canceled out with a correction waveform, after the output of the D/A converter has settled, this output is sample held and the step change is interpolated at a smoothing circuit, the deflection area is increased by positioning a electrostatic deflector offset around the optical axis relative to another electrostatic deflector, the response speed of the main deflection is improved by adding auxiliary deflection coils of one or two turn, and the alignment time is reduced by combining the coordinate conversion in the wafer area and in the chip area.
    Type: Grant
    Filed: June 20, 1996
    Date of Patent: February 24, 1998
    Assignee: Fujitsu Limited
    Inventors: Takamasa Satoh, Hiroshi Yasuda, Junichi Kai, Yoshihisa Oae, Hisayasu Nishino, Kiichi Sakamoto, Hidefumi Yabara, Isamu Seto, Masami Takigawa, Akio Yamada, Soichiro Arai, Tomohiko Abe, Takashi Kiuchi, Kenichi Miyazawa
  • Patent number: 5719402
    Abstract: To improve the throughput of an exposure system, the setting time during a step change in the output of an amplifier is reduced by switching resistance between the amplifier and a deflector. A glitch waveform generated during a step change in the output of a D/A converter at the preceding stage of the amplifier is anticipated and is cancelled out with a correction waveform. After the output of the D/A converter has settled, this output is sample-held and the step change is interpolated with a smoothing circuit. The deflection area is increased by positioning an electrostatic deflector offset around the optical axis relative to another electrostatic deflector, and the response speed of the main deflection is improved by adding auxiliary deflection coils of one or two turns. The alignment time is reduced by combining the coordinate conversion in the wafer area and in the chip area.
    Type: Grant
    Filed: April 4, 1996
    Date of Patent: February 17, 1998
    Assignee: Fujitsu Limited
    Inventors: Takamasa Satoh, Hiroshi Yasuda, Junichi Kai, Yoshihisa Oae, Hisayasu Nishino, Kiichi Sakamoto, Hidefumi Yabara, Isamu Seto, Masami Takigawa, Akio Yamada, Soichiro Arai, Tomohiko Abe, Takashi Kiuchi, Kenichi Miyazawa
  • Patent number: 5590048
    Abstract: In a block exposure pattern extracting system applied to a charged-particle beam exposure system having a block mask including a plurality of transparent stats having different shapes, a comparator unit compares first vectors connecting one of apexes of an input exposure pattern to other apexes thereof with second vectors connecting a reference point which is one of apexes of a unit block exposure pattern to other apexes of the unit block exposure pattern. A determining unit determines whether or not the first vectors coincide with the second vectors. An extracting unit extracts the input exposure pattern as the unit block exposure pattern when the determining unit determines that the first vectors coincide with the second vectors.
    Type: Grant
    Filed: June 4, 1993
    Date of Patent: December 31, 1996
    Assignee: Fujitsu Limited
    Inventors: Tomohiko Abe, Hiroshi Yasuda, Kiichi Sakamoto, Yoshihisa Oae
  • Patent number: 5546319
    Abstract: To improve in the throughput of an exposure system, the setting time during a step change in the output of an amplifier is reduced by switching resistance between the amplifier and a deflector, a glitch waveform generated during a step change in the output or a D/A converter at the preceding stage of the amplifier, is anticipated and is canceled out with a correction waveform, after the output of the D/A converter has settled, this output is sample held and the step change is interpolated at a smoothing circuit, the deflection area is increased by positioning a electrostatic deflector offset around the optical axis relative to another electrostatic deflector, the response speed of the main deflection is improved by adding auxiliary deflection coils of one or two turn, and the alignment time is reduced by combining the coordinate conversion in the wafer area and in the chip area.
    Type: Grant
    Filed: January 27, 1995
    Date of Patent: August 13, 1996
    Assignee: Fujitsu Limited
    Inventors: Takamasa Satoh, Hiroshi Yasuda, Junichi Kai, Yoshihisa Oae, Hisayasu Nishino, Kiichi Sakamoto, Hidefumi Yabara, Isamu Seto, Masami Takigawa, Akio Yamada, Soichiro Arai, Tomohiko Abe, Takashi Kiuchi, Kenichi Miyazawa
  • Patent number: 5537487
    Abstract: A method of dividing a block pattern for use in a block exposure, to be implemented on a computer, divides an arbitrary block which is to be formed in a block mask that is used for the block exposure when the arbitrary block is judged as including a prohibiting pattern which is undesirable from a point of view of the block exposure.
    Type: Grant
    Filed: June 9, 1994
    Date of Patent: July 16, 1996
    Assignee: Fujitsu Limited
    Inventors: Masaaki Miyajima, Hiroshi Yasuda, Satoru Yamazaki, Kiichi Sakamoto
  • Patent number: 5432314
    Abstract: A transparent mask plate used in a charged particle beam exposure apparatus includes a base plate, an exposure pattern area, and a calibration area. The exposure pattern area is formed in the base plate and has a plurality of transparent patterns for shaping a cross section of a charged particle beam into a block pattern. The calibration area is formed in the base plate, and has a plurality of transparent patterns used for obtaining a condition for deflecting the charged particle beam. The plurality of transparent patterns formed in the calibration area are arranged at the same pitch as the plurality of transparent patterns formed in the exposure pattern area. Each of the plurality of transparent patterns formed in the calibration area corresponds to one of the plurality of transparent patterns formed in the exposure pattern area.
    Type: Grant
    Filed: August 20, 1993
    Date of Patent: July 11, 1995
    Assignee: Fujitsu Limited
    Inventors: Satoru Yamazaki, Yoshihisa Oae, Kiichi Sakamoto, Akio Yamada
  • Patent number: 5422491
    Abstract: A charged particle beam exposure method exposes a desired exposure pattern on a substrate by a charged particle beam of a beam source and a deflection system for deflecting the charged particle beam transmitted through a mask.
    Type: Grant
    Filed: July 19, 1994
    Date of Patent: June 6, 1995
    Assignee: Fujitsu Limited
    Inventor: Kiichi Sakamoto