Patents by Inventor Tetsu Udagawa

Tetsu Udagawa 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: 6924525
    Abstract: The sheet resistance of a gate electrode 8A (a word line) of memory cell selection MISFET Q a DRAM and a sheet resistance of bit lines BL1, BL2 are, respectively, 2 ?/? or below. Interconnections of a peripheral circuit are formed during the step of forming the gate electrode 8A (the word line WL) or the bit lines BL1, BL2 by which the number of the steps of manufacturing the DRAM can be reduced.
    Type: Grant
    Filed: August 19, 2003
    Date of Patent: August 2, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Seiji Narui, Tetsu Udagawa, Kazuhiko Kajigaya, Makoto Yoshida
  • Publication number: 20040031980
    Abstract: The sheet resistance of a gate electrode 8A (a word line) of memory cell selection MISFET Q a DRAM and a sheet resistance of bit lines BL1, BL2 are, respectively, 2 &OHgr;/□ or below. Interconnections of a peripheral circuit are formed during the step of forming the gate electrode 8A (the word line WL) or the bit lines BL1, BL2 by which the number of the steps of manufacturing the DRAM can be reduced.
    Type: Application
    Filed: August 19, 2003
    Publication date: February 19, 2004
    Inventors: Seiji Narui, Tetsu Udagawa, Kazuhiko Kajigaya, Makoto Yoshida
  • Patent number: 6635918
    Abstract: The sheet resistance of a gate electrode 8A (a word line) of memory cell selection MISFET Q a DRAM and a sheet resistance of bit lines BL1, BL2 are, respectively, 2 &OHgr;/□ or below. Interconnections of a peripheral circuit are formed during the step of forming the gate electrode 8A (the word line WL) or the bit lines BL1, BL2 by which the number of the steps of manufacturing the DRAM can be reduced.
    Type: Grant
    Filed: November 17, 2000
    Date of Patent: October 21, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Seiji Narui, Tetsu Udagawa, Kazuhiko Kajigaya, Makoto Yoshida
  • Patent number: 6150689
    Abstract: The sheet resistance of a gate electrode 8A (a word line) of memory cell selection MISFET Q of a DRAM and a sheet resistance of bit lines BL.sub.1, BL.sub.2 are, respectively, 2 .OMEGA./.quadrature. or below. Interconnections of a peripheral circuit are formed during the step of forming the gate electrode 8A (the word line WL) or the bit lines BL.sub.1, BL.sub.2 by which the number of the steps of manufacturing the DRAM can be reduced.
    Type: Grant
    Filed: January 13, 1997
    Date of Patent: November 21, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Seiji Narui, Tetsu Udagawa, Kazuhiko Kajigaya, Makoto Yoshida
  • Patent number: 6108264
    Abstract: An ordinary read/write operation (normal operation) and a refresh operation are separated from one another and the number of read amplification circuits or, in other words, the number of sense amplifiers operating during the normal operation is made smaller than that during the refresh operation. Accordingly, a bit line charge/discharge current during the normal operation can be reduced.
    Type: Grant
    Filed: January 19, 1999
    Date of Patent: August 22, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Yasushi Takahashi, Takashi Shinoda, Masamichi Ishihara, Tetsu Udagawa, Kazumasa Yanagisawa
  • Patent number: 5862095
    Abstract: An ordinary read/write operation (normal operation) and a refresh operation are separated from one another and the number of read amplification circuits or in other words, the number of sense amplifiers operating during the normal operation is made smaller than that during the refresh operation. Accordingly, a bit line charge/discharge current during the normal operation can be reduced.
    Type: Grant
    Filed: October 31, 1997
    Date of Patent: January 19, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Yasushi Takahashi, Takashi Shinoda, Masamichi Ishihara, Tetsu Udagawa, Kazumasa Yanagisawa
  • Patent number: 5719815
    Abstract: An ordinary read/write operation (normal operation) and a refresh operation are separated from one another and the number of read amplification circuits or, in other words, the number of sense amplifiers operating during the normal operation is made smaller than that during the refresh operation. Accordingly, a bit line charge/discharge current during the normal operation can be reduced.
    Type: Grant
    Filed: July 18, 1995
    Date of Patent: February 17, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Yasushi Takahashi, Takashi Shinoda, Masamichi Ishihara, Tetsu Udagawa, Kazumasa Yanagisawa
  • Patent number: 5701031
    Abstract: A pair of DRAM chips 1A and 1B are mounted opposedly to each other with wiring means such as lead frames put therebetween, the lead frames being substantially integral with external terminals 3B. Then, these DRAM chips and lead frames are connected together by the conventional wire bonding method. Plural pairs of the thus-connected DRAM chips and lead frames are stacked and corresponding leads of the lead frames are connected in common to form a laminate. The plural DRAM chips thus mounted are activated selectively in accordance with a predetermined chip selection signal. Additionally, partial DRAM chips capable of partially functioning normally are combined together by utilizing the above chip mounting method to constitute a single DRAM package.
    Type: Grant
    Filed: July 25, 1994
    Date of Patent: December 23, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Satoshi Oguchi, Masamichi Ishihara, Kazuya Ito, Gen Murakami, Ichiro Anjoh, Toshiyuki Sakuta, Yasunori Yamaguchi, Yasuhiro Kasama, Tetsu Udagawa, Eiji Miyamoto, Youichi Matsuno, Hiroshi Satoh, Atsusi Nozoe
  • Patent number: 5506804
    Abstract: A Bi.CMOS semiconductor memory device is provided which includes an arrangement to simultaneously select a plurality of memory cells, followed by using a 3 bit Z addressing arrangement to determine a read or write operation for the simultaneously selected memory cells. To speed up the word line selection, a static selection type operation is used with the word line selecting voltage being greater than signal amplitude of the data lines during the write operation. Also, to speed up the read operation, separate common I/O lines are provided for the read and write operations. Read signals are transmitted as current signals, and then converted to voltage signals for improving reading speed. Also, improved arrangements are provided for resistance structure, logic circuitry, input circuitry, fuse cutting circuitry, drive circuitry, power circuitry, electrostatic protection circuitry, layout structure and testing methods for the semiconductor device.
    Type: Grant
    Filed: November 30, 1993
    Date of Patent: April 9, 1996
    Assignees: Hitachi, Ltd., VLSI Engineering Corp.
    Inventors: Kazumasa Yanagisawa, Tatsuyuki Ohta, Tetsu Udagawa, Kyoko Ishii, Hitoshi Miwa, Atsushi Nozoe, Masayuki Nakamura, Tetsurou Matsumoto, Yoshitaka Kinoshita, Yoshiaki Ouchi, Hiromi Tsukada, Shoji Wada, Kazuo Mihashi, Yutaka Kobayashi, Goro Kitsukawa
  • Patent number: 5426616
    Abstract: A voltage conversion circuit of the present invention is equipped with means for generating a first voltage stabilized with respect to ground potential of a semiconductor integrated circuit device including the circuit, means for generating second voltage stabilized with respect to an external supply voltage of the semiconductor integrated circuit device, and selection means for selecting either the first voltage or the second voltage. The first voltage age, stabilized with respect to the ground potential, is selected and used as the voltage at the time of normal operation, and the second voltage, stabilized with respect to the external supply voltage, is selected and used at the time of aging test. In this case, means for trimming the first voltage and/or the second voltage is, preferably, provided to raise the voltage accuracy.
    Type: Grant
    Filed: May 16, 1994
    Date of Patent: June 20, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiko Kajigaya, Tetsu Udagawa, Kyoko Ishii, Manabu Tsunozaki, Kazuyoshi Oshima, Masashi Horiguchi, Jun Etoh, Masakazu Aoki, Shin'ichi Ikenaga, Kiyoo Itoh
  • Patent number: 5332922
    Abstract: A pair of DRAM chips 1A and 1B are mounted opposedly to each other with wiring means such as lead frames put therebetween, the lead frames being substantially integral with external terminals 3B. Then, these DRAM chips and lead frames are connected together by the conventional wire bonding method. Each chip is bonded with an associated lead frame and each lead frame is disposed as plural lead frame conductors contacting mutually lead frame conductors associated with similarly function bonding pads, i.e. external terminals of the chips, of the other one of the pair of chips. Ones or plural pairs of the thus-connected DRAM chips and lead frames are stacked and corresponding leads of the lead frames are connected in common to form a laminate. The plural DRAM chips thus mounted are activated selectively in accordance with a predetermined chip selection signal.
    Type: Grant
    Filed: April 26, 1991
    Date of Patent: July 26, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Satoshi Oguchi, Masamichi Ishihara, Kazuya Ito, Gen Murakami, Ichiro Anjoh, Toshiyuki Sakuta, Yasunori Yamaguchi, Yasuhiro Kasama, Tetsu Udagawa, Eiji Miyamoto, Youichi Matsuno, Hiroshi Satoh, Atsusi Nozoe
  • Patent number: 5276648
    Abstract: A Bi.CMOS semiconductor memory device is provided which includes an arrangement to simultaneously select a plurality of memory cells, followed by using a 3 bit Z addressing arrangement to determine a read or write operation for the simultaneously selected memory cells. To speed up the word line selection, a static selection type operation is used with the word line selecting voltage being greater than signal amplitude of the data lines during the write operation. Also, to speed up the read operation, separate common I/O lines are provided for the read and write operations. Read signals are transmitted as current signals, and then converted to voltage signals for improving reading speed. Also, improved arrangements are provided for resistance structure, logic circuitry, input circuitry, fuse cutting circuitry, drive circuitry, power circuitry, electrostatic protection circuitry, layout structure and testing methods for the semiconductor device.
    Type: Grant
    Filed: January 8, 1992
    Date of Patent: January 4, 1994
    Assignees: Hitachi, Ltd., Hitachi VLSI Engineering Corp.
    Inventors: Kazumasa Yanagisawa, Tatsuyuki Ohta, Tetsu Udagawa, Kyoko Ishii, Hitoshi Miwa, Atsushi Nozoe, Masayuki Nakamura, Tetsurou Matsumoto, Yoshitaka Kinoshita, Yoshiaki Ouchi, Hiromi Tsukada, Shoji Wada, Kazuo Mihashi, Yutaka Kobayashi, Goro Kitsukawa
  • Patent number: 5150325
    Abstract: A Bi.CMOS semiconductor memory device is provided which includes an arrangement to simultaneously select a plurality of memory cells, followed by using a 3 bit Z addressing arrangement to determine a read or write operation for the simultaneously selected memory cells. To speed up the word line selection, a static selection type operation is used with the word line selecting voltage being greater than signal amplitude of the data lines during the write operation. Also, to speed up the read operation, separate common I/O lines are provided for the read and write operations. Read signals are transmitted as curent signals, and then converted to voltage signals for improving reading speed. Also, improved arrangements are provided for resistance structure, logic circuitry, input circuitry, fuse cutting circuitry, drive circuitry, power circuitry, electrostatic protection circuitry, layout structure and testing methods for the semiconductor device.
    Type: Grant
    Filed: March 20, 1990
    Date of Patent: September 22, 1992
    Assignees: Hitachi, Ltd., Hitachi VLSI Engineering Corp
    Inventors: Kazumasa Yanagisawa, Tatsuyuki Ohta, Tetsu Udagawa, Kyoko Ishii, Hitoshi Miwa, Atsushi Nozoe, Masayuki Nakamura, Tetsurou Matsumoto, Yoshitaka Kinoshita, Yoshiaki Ouchi, Hiromi Tsukada, Shoji Wada, Kazuo Mihashi, Yutaka Kobayashi, Goro Kitsukawa
  • Patent number: 5043947
    Abstract: A memory device is provided including a plurality of memory arrays and peripheral circuits. For example, in a dynamic RAM the peripheral circuitry will include row address decoders, column address decoders, sense amplifiers and main amplifiers disposed in such a manner as to correspond to the memory arrays, respectively. The desired row address decoders, column address decoders, sense amplifiers and main amplifiers are selectively operated in accordance with a common array selection signal generated on the basis of at least part of row address signals. Accordingly, only the row address decoders, column address decoders, sense amplifiers and main amplifiers corresponding to the memory array containing the designated memory cells are operated selectively in accordance with the common array selection signal. It is thus possible to reduce power consumption of the dynamic RAM and to simplify the structure of the peripheral circuits and wirings.
    Type: Grant
    Filed: May 30, 1990
    Date of Patent: August 27, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Kazuyoshi Oshima, Takashi Yamazaki, Yasuhiro Kasama, Tetsu Udagawa, Hiroaki Kotani
  • Patent number: 4941129
    Abstract: A memory device is provided including a plurality of memory arrays and peripheral circuits. For example, in a dynamic RAM the peripheral circuitry will include row address decoders, column address decoders, sense amplifiers and main amplifiers disposed in such a manner as to correspond to the memory arrays, respectively. The desired row address decoders, column address decoders, sense amplifiers and main amplifiers are selectively operated in accordance with a common array selection signal generated on the basis of at least part of row address signals. Accordingly, only the row address decoders, column address decoders, sense amplifiers and main amplifiers corresponding to the memory array containing the designated memory cells are operated selectively in accordance with the common array selection signal. It is thus possible to reduce power consumption of the dynamic RAM and to simplify the structure of the peripheral circuits and wirings.
    Type: Grant
    Filed: August 29, 1988
    Date of Patent: July 10, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Kazuyoshi Oshima, Takashi Yamazaki, Yasuhiro Kasama, Tetsu Udagawa, Hiroaki Kotani
  • Patent number: RE37539
    Abstract: A pair of DRAM chips 1A and 1B are mounted opposedly to each other with wiring means such as lead frames put therebetween, the lead frames being substantially integral with external terminals 3B. Then, these DRAM chips and lead frames are connected together by the conventional wire bonding method. Plural pairs of the thus-connected DRAM chips and lead frames are stacked and corresponding leads of the lead frames are connected in common to form a laminate. The plural DRAM chips thus mounted are activated selectively in accordance with a predetermined chip selection signal. Additionally, partial DRAM chips capable of partially functioning normally are combined together by utilizing the above chip mounting method to constitute a single DRAM package.
    Type: Grant
    Filed: December 23, 1999
    Date of Patent: February 5, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Satoshi Oguchi, Masamichi Ishihara, Kazuya Ito, Gen Murakami, Ichiro Anjoh, Toshiyuki Sakuta, Yasunori Yamaguchi, Yasuhiro Kasama, Tetsu Udagawa, Eiji Momose, Youichi Matsuno, Hiroshi Satoh, Atsusi Nozoe