Patents by Inventor Kazuhiko Saitoh

Kazuhiko Saitoh 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: 6060352
    Abstract: A method for fabricating DRAMs each having a COB structure, and the semiconductor device formed by this method, are provided. In one embodiment, the word line and/or bit line is covered with an insulating film having a comparatively small etching rate. Contact holes are formed while being defined by those insulating films in self-alignment.
    Type: Grant
    Filed: January 28, 1998
    Date of Patent: May 9, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Toshihiro Sekiguchi, Hideo Aoki, Yoshitaka Tadaki, Keizo Kawakita, Jun Murata, Katsuo Yuhara, Michio Nishimura, Kazuhiko Saitoh, Minoru Ohtsuka, Masayuki Yasuda, Toshiyuki Kaeriyama, Songsu Cho
  • Patent number: 6023084
    Abstract: A semiconductor memory device has a semiconductor substrate, and memory cells provided at intersections between word line conductors and bit line conductors. Adjacent two memory cells for each bit line conductor form a memory cell pair unit structure, in which first semiconductor regions of the transistors of the adjacent two memory cells are united at their boundary into a single region and are connected to one of the bit line conductors via a bit line connection conductor, the gate electrodes of the transistors of the adjacent two memory cells are connected to word line conductors adjacent to each other, respectively, and the second semiconductor regions of the transistors of the adjacent two memory cells are connected to the respective information storage capacitors.
    Type: Grant
    Filed: October 19, 1998
    Date of Patent: February 8, 2000
    Assignees: Hitachi, Ltd., Texas Instruments Inc.
    Inventors: Yoshitaka Tadaki, Jun Murata, Toshihiro Sekiguchi, Hideo Aoki, Keizo Kawakita, Hiroyuki Uchiyama, Michio Nishimura, Michio Tanaka, Yuji Ezaki, Kazuhiko Saitoh, Katsuo Yuhara, Songsu Cho
  • Patent number: 5933724
    Abstract: A phase shifting mask is used for manufacturing a semiconductor integrated circuit device including a conductor pattern in which the line width of patterned conductor strips or the space between patterned conductor strips is not constant. For main transparent areas in the mask corresponding to the conductor pattern, auxiliary pattern segments are provided for compensating changes in the phase distribution of transmitted light caused by changes of the line width or the space. Alternately, the spaces between the conductor strips are adjusted to suppress the changes in the phase distribution of transmitted light. Whether the auxiliary pattern segments should have the phase shifting function is determined depending upon the disposition of the main transparent areas.
    Type: Grant
    Filed: August 26, 1996
    Date of Patent: August 3, 1999
    Assignees: Hitachi, Ltd., Texas Instruments
    Inventors: Toshihiro Sekiguchi, Yoshitaka Tadaki, Keizo Kawakita, Jun Murata, Katsuo Yuhara, Toshikazu Kumai, Michio Tanaka, Michio Nishimura, Kazuhiko Saitoh, Takatoshi Kakizaki, Takeshi Sakai, Toshiyuki Kaeriyama, Songsu Cho
  • Patent number: 5933726
    Abstract: A semiconductor device, such as a dynamic RAM, and method of making it. A number of stacked cell capacitors are placed at a prescribed spacing in an alignment direction on top of a p.sup.- -type silicon substrate (1). Each capacitor has a nearly perpendicular cylindrical lower electrode (cylindrical polysilicon layer (96)), a dielectric film (silicon nitride film (77)), and upper electrode (plate electrode (78) made of polysilicon). The spacing in the alignment direction is smaller than the inner diameter of the lower electrode.
    Type: Grant
    Filed: August 27, 1996
    Date of Patent: August 3, 1999
    Assignee: Texas Instruments Incorporated
    Inventors: Michio Nishimura, Kazuhiko Saitoh, Masayuki Yasuda, Takashi Hayakawa, Michio Tanaka, Yuji Ezaki, Katsuo Yuhara, Minoru Ohtsuka, Toshikazu Kumai, Songsu Cho, Toshiyuki Kaeriyama, Keizo Kawakita, Toshihiro Sekiguchi, Yoshitaka Tadaki, Jun Murata, Hideo Aoki, Akihiko Konno, Kiyomi Katsuyama, Takafumi Tokunaga, Yoshimi Torii
  • Patent number: 5831300
    Abstract: A semiconductor memory device has a semiconductor substrate, word line conductors and bit line conductors, and memory cells provided at intersections between the word line conductors and bit line conductors. Adjacent two memory cells for each bit line conductor form a memory cell pair unit structure, in which first semiconductor regions of the transistors of the adjacent two memory cells are united at their boundary into a single region and are connected to one of the bit line conductors via a bit line connection conductor, the gate electrodes of the transistors of the adjacent two memory cells are connected to word line conductors adjacent to each other, respectively, the second semiconductor regions of the transistors of the adjacent two memory cells are connected to the respective information storage capacitors.
    Type: Grant
    Filed: October 16, 1996
    Date of Patent: November 3, 1998
    Assignees: Hitachi, Ltd., Texas Instruments Incorporated
    Inventors: Yoshitaka Tadaki, Jun Murata, Toshihiro Sekiguchi, Hideo Aoki, Keizo Kawakita, Hiroyuki Uchiyama, Michio Nishimura, Michio Tanaka, Yuji Ezaki, Kazuhiko Saitoh, Katsuo Yuhara, Songsu Cho
  • Patent number: 5804479
    Abstract: The etch-back amount of a silicon oxide film of a memory array which is a higher altitude portion is increased when etching back and flattening the silicon oxide film by arranging a first-layer wiring on a BPSG film covering an upper electrode of an information-storing capacitative element only in a peripheral circuit but not arranging it in the memory array.Thus, a DRAM having a stacked capacitor structure is obtained such that the level difference between the memory array and peripheral circuit is decreased, and the formation of wiring and connection holes are easy.
    Type: Grant
    Filed: August 9, 1996
    Date of Patent: September 8, 1998
    Assignees: Hitachi, Ltd., Texas Instruments Inc.
    Inventors: Hideo Aoki, Jun Murata, Yoshitaka Tadaki, Toshihiro Sekiguchi, Keizo Kawakita, Takashi Hayakawa, Katsutoshi Matsunaga, Kazuhiko Saitoh, Michio Nishimura, Minoru Ohtsuka, Katsuo Yuhara, Michio Tanaka, Yuji Ezaki, Toshiyuki Kaeriyama, SongSu Cho
  • Patent number: 5732009
    Abstract: A DRAM has memory cells provided at crossing points between word line conductors and bit line conductors. Each memory cell has a cell selection transistor and an information storage capacitor arranged over the bit line conductors. Unit active regions are defined in a main surface of a semiconductor substrate by a field isolation pattern. The field isolation pattern has a controlled length of extension of bird's beaks so that channel formation regions in each unit active region has almost no stepped portion to provide the cell selection transistors with a stabilized threshold voltage.
    Type: Grant
    Filed: July 22, 1996
    Date of Patent: March 24, 1998
    Assignees: Hitachi, Ltd., Texas Instruments Incorporated
    Inventors: Yoshitaka Tadaki, Jun Murata, Katsuo Yuhara, Yuji Ezaki, Michio Tanaka, Michio Nishimura, Kazuhiko Saitoh, Takatoshi Kakizaki, Shinya Nishio, Takeshi Sakai, Songsu Cho
  • Patent number: 5578849
    Abstract: A memory device has a semiconductor substrate, and memory cells provided at intersections between word line conductors and bit line conductors. Each memory cell has a switching transistor and an information storage capacitor. Adjacent two memory cells for each bit line conductor form a memory cell pair unit structure, in which first semiconductor regions of the transistors of the adjacent two memory cells are united at their boundary into a single region and are connected to one of the bit line conductors via a bit line connection conductor, the gate electrodes of the transistors of the adjacent two memory cells are connected to word line conductors adjacent to each other, respectively, the second semiconductor regions of the transistors of the adjacent two memory cells are connected to the respective information storage capacitors.
    Type: Grant
    Filed: November 16, 1994
    Date of Patent: November 26, 1996
    Assignees: Hitachi, Ltd., Texas Instruments, Inc.
    Inventors: Yoshitaka Tadaki, Jun Murata, Toshihiro Sekiguchi, Hideo Aoki, Keizo Kawakita, Hiroyuki Uchiyama, Michio Nishimura, Michio Tanaka, Yuji Ezaki, Kazuhiko Saitoh, Katsuo Yuhara, Songsu Cho