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).
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Publication number: 20010013581Abstract: 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: ApplicationFiled: April 6, 2001Publication date: August 16, 2001Inventors: 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
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Patent number: 6242751Abstract: 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: GrantFiled: July 15, 1999Date of Patent: June 5, 2001Assignee: Fujitsu LimitedInventors: 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
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Patent number: 6222195Abstract: 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: GrantFiled: August 11, 2000Date of Patent: April 24, 2001Assignee: Fujitsu LimitedInventors: Akio Yamada, Satoru Sagou, Hitoshi Watanabe, Satoru Yamazaki, Kiichi Sakamoto, Manabu Ohno, Kenichi Kawakami, Katsuhiko Kobayashi
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Patent number: 6137111Abstract: 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: GrantFiled: May 28, 1998Date of Patent: October 24, 2000Assignee: Fujitsu LimitedInventors: Akio Yamada, Satoru Sagou, Hitoshi Watanabe, Satoru Yamazaki, Kiichi Sakamoto, Manabu Ohno, Kenichi Kawakami, Katsuhiko Kobayashi
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Patent number: 6090527Abstract: 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: GrantFiled: June 1, 1998Date of Patent: July 18, 2000Assignee: Fujitsu LimitedInventors: Satoru Yamazaki, Kiichi Sakamoto, Hiroshi Yasuda, Takayuki Sakakibara, Satoru Sagoh
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Patent number: 6087048Abstract: 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: GrantFiled: February 24, 1999Date of Patent: July 11, 2000Assignee: Advantest CorporationInventors: Yoshio Suzaki, Takayuki Sakakibara, Kiichi Sakamoto
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Patent number: 5969365Abstract: 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: GrantFiled: August 26, 1997Date of Patent: October 19, 1999Assignee: Fujitsu LimitedInventors: 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
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Patent number: 5965895Abstract: 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: GrantFiled: November 4, 1997Date of Patent: October 12, 1999Assignee: Fujitsu LimitedInventors: 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
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Patent number: 5952155Abstract: 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: GrantFiled: July 21, 1998Date of Patent: September 14, 1999Assignee: Fujitsu LimitedInventors: Takayuki Sakakibara, Satoru Sagoh, Satoru Yamazaki, Kiichi Sakamoto, Hiroshi Yasuda
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Patent number: 5849437Abstract: 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: GrantFiled: January 24, 1996Date of Patent: December 15, 1998Assignee: Fujitsu LimitedInventors: Satoru Yamazaki, Kiichi Sakamoto, Hiroshi Yasuda, Takayuki Sakakibara, Satoru Sagoh
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Patent number: 5830612Abstract: 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: GrantFiled: September 11, 1996Date of Patent: November 3, 1998Assignee: Fujitsu LimitedInventors: Akio Yamada, Satoru Sagou, Hitoshi Watanabe, Satoru Yamazaki, Kiichi Sakamoto, Manabu Ohno, Kenichi Kawakami, Katsuhiko Kobayashi
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Patent number: 5824437Abstract: 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: GrantFiled: July 22, 1996Date of Patent: October 20, 1998Assignee: Fujitsu LimitedInventors: Takayuki Sakakibara, Satoru Sagoh, Satoru Yamazaki, Kiichi Sakamoto, Hiroshi Yasuda
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Patent number: 5757015Abstract: 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: GrantFiled: April 18, 1996Date of Patent: May 26, 1998Assignee: Fujitsu LimitedInventors: 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
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Patent number: 5721432Abstract: 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: GrantFiled: June 20, 1996Date of Patent: February 24, 1998Assignee: Fujitsu LimitedInventors: 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
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Patent number: 5719402Abstract: 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: GrantFiled: April 4, 1996Date of Patent: February 17, 1998Assignee: Fujitsu LimitedInventors: 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
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Patent number: 5590048Abstract: 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: GrantFiled: June 4, 1993Date of Patent: December 31, 1996Assignee: Fujitsu LimitedInventors: Tomohiko Abe, Hiroshi Yasuda, Kiichi Sakamoto, Yoshihisa Oae
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Patent number: 5546319Abstract: 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: GrantFiled: January 27, 1995Date of Patent: August 13, 1996Assignee: Fujitsu LimitedInventors: 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
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Patent number: 5537487Abstract: 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: GrantFiled: June 9, 1994Date of Patent: July 16, 1996Assignee: Fujitsu LimitedInventors: Masaaki Miyajima, Hiroshi Yasuda, Satoru Yamazaki, Kiichi Sakamoto
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Patent number: 5432314Abstract: 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: GrantFiled: August 20, 1993Date of Patent: July 11, 1995Assignee: Fujitsu LimitedInventors: Satoru Yamazaki, Yoshihisa Oae, Kiichi Sakamoto, Akio Yamada
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Patent number: 5422491Abstract: 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: GrantFiled: July 19, 1994Date of Patent: June 6, 1995Assignee: Fujitsu LimitedInventor: Kiichi Sakamoto