Patents by Inventor Yoshiyuki Ishigaki

Yoshiyuki Ishigaki 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: 6891743
    Abstract: A CMOS-SRAM has a plurality of full CMOS type memory cells (1) and a capacity plate (2). The memory cells (1) are two-dimensionally arranged in the row direction and in the column direction. The capacity plate 2 adds an additional capacity to nodes ND1 and ND2 for storing data in order to reduce soft errors. The capacity plate (2) is common with the plurality of memory cells (1). The capacity plates (2) are separated by every column, that is in the row direction. The capacity plate (2) is connected to a power voltage line VDD so as to simplify the voltage supplying system. When a stand-by failure occurs in the memory cell (1) of a certain column, the memory cell (1) is replaced with a redundant memory cell.
    Type: Grant
    Filed: July 16, 2002
    Date of Patent: May 10, 2005
    Assignee: Renesas Technology Corp.
    Inventors: Shigeki Ohbayashi, Yoshiyuki Ishigaki, Takahiro Yokoyama
  • Publication number: 20050083756
    Abstract: A semiconductor storage device includes a memory cell array, a plurality of word lines, a plurality of bit lines, a first gate wiring element 3a, 3b, a second gate wiring element 3c, 3d, a first connector 5a, 5b, and a second connector 5c, 5d. Each memory cell 10 has first and second sets having a driver transistor 11, a load transistor 12, and an access transistor 13. The word lines are arranged in parallel to each other along a first direction. The bit lines are arranged in parallel to each other along a second direction perpendicular to the first direction. The first gate wiring element comprises a gate electrode of the first driver transistor and the first load transistor, and has a rectangular shape having straight line on opposite sides. The second gate wiring element comprises a gate electrode of the access transistor and has a rectangular shape having straight line on opposite sides.
    Type: Application
    Filed: October 25, 2004
    Publication date: April 21, 2005
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hidemoto Tomita, Shigeki Ohbayashi, Yoshiyuki Ishigaki
  • Patent number: 6853022
    Abstract: A semiconductor memory device having as its main storage portion a capacitor storing charges as binary information and an access transistor controlling input/output of the charges to/from the capacitor, and eliminating the need for refresh, is obtained. The semiconductor memory device includes a capacitor with a storage node located above a semiconductor substrate and holding the charges corresponding to a logical level of stored binary information, an access transistor located on the semiconductor substrate surface and controlling input/output of the charges accumulated in the capacitor, and a latch circuit located on the semiconductor substrate and maintaining a potential of the capacitor storage node. At least one of circuit elements constituting the latch circuit is located above the access transistor.
    Type: Grant
    Filed: January 29, 2003
    Date of Patent: February 8, 2005
    Assignee: Renesas Technology Corp.
    Inventors: Tsuyoshi Koga, Yoshiyuki Ishigaki, Motoi Ashida, Yukio Maki, Yasuhiro Fujii, Tomohiro Hosokawa, Takashi Terada, Makoto Dei, Yasuichi Masuda
  • Patent number: 6831852
    Abstract: A semiconductor device includes: a capacitor: an access transistor with impurity regions, controlling input/output of charge stored in the capacitor, one of the impurity regions being electrically connected to the capacitor; a latch circuit located above a silicon substrate, and storing the potential of a storage node of the capacitor; and a bit line connected to the other of the impurity regions of the access transistor T6. At least a portion of the latch circuit is formed above the bit line.
    Type: Grant
    Filed: May 22, 2003
    Date of Patent: December 14, 2004
    Assignee: Renesas Technology Corp.
    Inventors: Yoshiyuki Ishigaki, Tsuyoshi Koga, Yasuhiro Fujii
  • Patent number: 6812534
    Abstract: An SRAM comprises a memory cell including first and second access nMOS transistors, first and second driver nMOS transistors and first and second load pMOS transistors, polysilicon wires forming gates of the first and second access nMOS transistors and polysilicon wires extending in the same direction as the polysilicon wires for forming gates of the first and second driver nMOS transistors and gates of the first and second load pMOS transistors. The gate widths of the first and second access nMOS transistors and those of the first and second driver nMOS transistors are equalized with each other.
    Type: Grant
    Filed: February 13, 2003
    Date of Patent: November 2, 2004
    Assignee: Renesas Technology Corp.
    Inventors: Yoshiyuki Ishigaki, Tomohiro Hosokawa, Yukio Maki
  • Patent number: 6812574
    Abstract: A semiconductor storage device includes a memory cell array, a plurality of word lines, a plurality of bit lines, a first gate wiring element 3a, 3b, a second gate wiring element 3c, 3d, a first connector 5a, 5b, and a second connector 5c, 5d. Each memory cell 10 has first and second sets having a driver transistor 11, a load transistor 12, and an access transistor 13. The word lines are arranged in parallel to each other along a first direction. The bit lines are arranged in parallel to each other along a second direction perpendicular to the first direction. The first gate wiring element comprises a gate electrode of the first driver transistor and the first load transistor, and has a rectangular shape having straight line on opposite sides. The second gate wiring element comprises a gate electrode of the access transistor and has a rectangular shape having straight line on opposite sides.
    Type: Grant
    Filed: July 9, 2002
    Date of Patent: November 2, 2004
    Assignee: Renesas Technology Corp.
    Inventors: Hidemoto Tomita, Shigeki Ohbayashi, Yoshiyuki Ishigaki
  • Patent number: 6781869
    Abstract: A semiconductor memory having: a full CMOS-type of memory cell (10) including an n-type bulk access transistor (7, 8), an n-type bulk driver transistor (5, 6) and a p-type bulk load transistor (3, 4) by twos, and a charge capacitance adding charge capacitor element (9) connected to cell nodes (N1, N2) in order to secure a soft error resistance. In the semiconductor memory, an insulating film (14) and a conductive film (15) are directly formed on each upper side of first and second cell nodes (N1, N2) for constituting a charge capacitor element (9) for adding a charge capacitance. The insulating film (14) is held between the cell node (N1, N2) and the conductive film (15), covering both first and second cell nodes (N1, N2) in common.
    Type: Grant
    Filed: December 26, 2002
    Date of Patent: August 24, 2004
    Assignee: Renesas Technology Corp.
    Inventors: Shigeki Ohbayashi, Yoshiyuki Ishigaki, Takahiro Yokoyama
  • Patent number: 6774441
    Abstract: A semiconductor device according to the present invention includes a silicon substrate having a main surface, a gate electrode provided on the main surface of the silicon substrate, a first sidewall insulating film provided to cover a side surface of the gate electrode and including two layers of an oxide sidewall film as an underlay and a nitride sidewall film, a second sidewall insulating film provided to cover a surface of the first sidewall insulating film, and a cobalt silicide layer arranged above source and drain regions and at a position farther than the second sidewall insulating film from the gate electrode. The second sidewall insulating film fills in a removed portion located at a lower end of the oxide sidewall film. This allows a semiconductor device formed by employing a salicide process to prevent increase of leak current caused by a metal silicide layer.
    Type: Grant
    Filed: January 13, 2003
    Date of Patent: August 10, 2004
    Assignee: Renesas Technology Corp.
    Inventors: Yukio Maki, Yoshiyuki Ishigaki, Yasuhiro Fujii
  • Publication number: 20040150019
    Abstract: A semiconductor memory device includes a memory cell, and first and second capacitive elements. The memory cell has a pair of inverters each including first and second driver nMOS transistors and first and second TFTs, and first and second access nMOS transistors. The first and second capacitive elements is connected to the drain of first and second access nMOS transistors, the drain of first and second driver nMOS transistors, and the drain of first and second TFTs. The gate width of first and second driver nMOS transistors is set at least 1.2 times longer than the gate width of first and second access nMOS transistors.
    Type: Application
    Filed: July 25, 2003
    Publication date: August 5, 2004
    Applicant: RENESAS TECHNOLOGY CORP.
    Inventors: Yasushi Nakashima, Takashi Izutsu, Yoshiyuki Ishigaki
  • Publication number: 20040120179
    Abstract: A semiconductor device includes: a capacitor: an access transistor with impurity regions, controlling input/output of charge stored in the capacitor, one of the impurity regions being electrically connected to the capacitor; a latch circuit located above a silicon substrate, and storing the potential of a storage node of the capacitor; and a bit line connected to the other of the impurity regions of the access transistor T6. At least a portion of the latch circuit is formed above the bit line.
    Type: Application
    Filed: May 22, 2003
    Publication date: June 24, 2004
    Applicant: RENESAS TECHNOLOGY CORP.
    Inventors: Yoshiyuki Ishigaki, Tsuyoshi Koga, Yasuhiro Fujii
  • Publication number: 20040046214
    Abstract: An SRAM comprises a memory cell including first and second access nMOS transistors, first and second driver nMOS transistors and first and second load pMOS transistors, polysilicon wires forming gates of the first and second access nMOS transistors and polysilicon wires extending in the same direction as the polysilicon wires for forming gates of the first and second driver nMOS transistors and gates of the first and second load pMOS transistors. The gate widths of the first and second access nMOS transistors and those of the first and second driver nMOS transistors are equalized with each other.
    Type: Application
    Filed: February 13, 2003
    Publication date: March 11, 2004
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Yoshiyuki Ishigaki, Tomohiro Hosokawa, Yukio Maki
  • Publication number: 20040032764
    Abstract: A semiconductor memory device having as its main storage portion a capacitor storing charges as binary information and an access transistor controlling input/output of the charges to/from the capacitor, and eliminating the need for refresh, is obtained. The semiconductor memory device includes a capacitor with a storage node located above a semiconductor substrate and holding the charges corresponding to a logical level of stored binary information, an access transistor located on the semiconductor substrate surface and controlling input/output of the charges accumulated in the capacitor, and a latch circuit located on the semiconductor substrate and maintaining a potential of the capacitor storage node. At least one of circuit elements constituting the latch circuit is located above the access transistor.
    Type: Application
    Filed: January 29, 2003
    Publication date: February 19, 2004
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Tsuyoshi Koga, Yoshiyuki Ishigaki, Motoi Ashida, Yukio Maki, Yasuhiro Fujii, Tomohiro Hosokawa, Takashi Terada, Makoto Dei, Yasuichi Masuda
  • Publication number: 20040026747
    Abstract: A semiconductor device according to the present invention includes a silicon substrate having a main surface, a gate electrode provided on the main surface of the silicon substrate, a first sidewall insulating film provided to cover a side surface of the gate electrode and including two layers of an oxide sidewall film as an underlay and a nitride sidewall film, a second sidewall insulating film provided to cover a surface of the first sidewall insulating film, and a cobalt silicide layer arranged above source and drain regions and at a position farther than the second sidewall insulating film from the gate electrode. The second sidewall insulating film fills in a removed portion located at a lower end of the oxide sidewall film. This allows a semiconductor device formed by employing a salicide process to prevent increase of leak current caused by a metal silicide layer.
    Type: Application
    Filed: January 13, 2003
    Publication date: February 12, 2004
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Yukio Maki, Yoshiyuki Ishigaki, Yasuhiro Fujii
  • Patent number: 6632716
    Abstract: A semiconductor device is comprised of: an element isolating film formed on one major surface of a semiconductor substrate; an element forming region formed on the major surface and surrounded by the element isolating film; a gate electrode formed via a gate insulating film on the element forming region and extended over the element isolating film; first and second impurity regions formed in the element forming region, whose portions exposed from a surface of the semiconductor substrate are made in contact with the element isolating film and are located opposite to each other under the gate electrode; a first insulating film formed near the gate electrode on the first impurity region, and extended over the gate electrode and near an extended portion of the gate electrode within the element isolating film; and a second insulating film formed near the gate electrode on the second impurity region.
    Type: Grant
    Filed: February 8, 2001
    Date of Patent: October 14, 2003
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Yoshiyuki Ishigaki
  • Publication number: 20030142538
    Abstract: A semiconductor memory having: a full CMOS-type of memory cell (10) including an n-type bulk access transistor (7, 8), an n-type bulk driver transistor (5, 6) and a p-type bulk load transistor (3, 4) by twos, and a charge capacitance adding charge capacitor element (9) connected to cell nodes (N1, N2) in order to secure a soft error resistance. In the semiconductor memory, an insulating film (14) and a conductive film (15) are directly formed on each upper side of first and second cell nodes (N1, N2) for constituting a charge capacitor element (9) for adding a charge capacitance. The insulating film (14) is held between the cell node (N1, N2) and the conductive film (15), covering both first and second cell nodes (N1, N2) in common.
    Type: Application
    Filed: December 26, 2002
    Publication date: July 31, 2003
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Shigeki Ohbayashi, Yoshiyuki Ishigaki, Takahiro Yokoyama
  • Publication number: 20030133335
    Abstract: A CMOS-SRAM has a plurality of full CMOS type memory cells (1) and a capacity plate (2). The memory cells (1) are two-dimensionally arranged in the row direction and in the column direction. The capacity plate 2 adds an additional capacity to nodes ND1 and ND2 for storing data in order to reduce soft errors. The capacity plate (2) is common with the plurality of memory cells (1). The capacity plates (2) are separated by every column, that is in the row direction. The capacity plate (2) is connected to a power voltage line VDD so as to simplify the voltage supplying system. When a stand-by failure occurs in the memory cell (1) of a certain column, the memory cell (1) is replaced with a redundant memory cell.
    Type: Application
    Filed: July 16, 2002
    Publication date: July 17, 2003
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigeki Ohbayashi, Yoshiyuki Ishigaki, Takahiro Yokoyama
  • Publication number: 20030128565
    Abstract: A semiconductor storage device includes a memory cell array, a plurality of word lines, a plurality of bit lines, a first gate wiring element 3a, 3b, a second gate wiring element 3c, 3d, a first connector 5a, 5b, and a second connector 5c, 5d. Each memory cell 10 has first and second sets having a driver transistor 11, a load transistor 12, and an access transistor 13. The word lines are arranged in parallel to each other along a first direction. The bit lines are arranged in parallel to each other along a second direction perpendicular to the first direction. The first gate wiring element comprises a gate electrode of the first driver transistor and the first load transistor, and has a rectangular shape having straight line on opposite sides. The second gate wiring element comprises a gate electrode of the access transistor and has a rectangular shape having straight line on opposite sides.
    Type: Application
    Filed: July 9, 2002
    Publication date: July 10, 2003
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hidemoto Tomita, Shigeki Ohbayashi, Yoshiyuki Ishigaki
  • Patent number: 6404024
    Abstract: There is described a semiconductor device whose structure is suitable for controlling the threshold values for operation of transistors, as well as for inexpensive fabrication of transistors whose threshold values for operation assume small values. A field-oxide film is formed on a silicon substrate through use of an oxidation-resistance mask, by means of the local oxidation of silicon (LOCOS) method. On the silicon substrate, there is formed an access transistor whose source/drain region is to be formed in active regions and whose channel region is to be formed in another active region. A protuberance is formed in the field-oxide film so as to bulge toward the active region where the channel region is to be formed. A bird's beak, which would grow during the course of formation of the field-oxide film, encounters difficulty in growing in the protuberance, as a result of which a trench is formed in a boundary area between the protuberance and the active region where the channel region is to be formed.
    Type: Grant
    Filed: March 2, 2000
    Date of Patent: June 11, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Yoshiyuki Ishigaki
  • Patent number: 6271569
    Abstract: According to a semiconductor device and a method of manufacturing the same, a storage node has an increased capacity, and a resistance against soft error is improved. A GND interconnection is formed on a first interconnection layer including storage node portions with a dielectric film therebetween. Thereby, the storage node portions, the dielectric film, and the GND interconnection form a capacity element of the storage node portion. The first interconnection layer is arranged symmetrically around the center of the memory cell, and a plurality of memory cells having the same layout and neighboring to each other are arranged along the word lines.
    Type: Grant
    Filed: January 16, 1998
    Date of Patent: August 7, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yoshiyuki Ishigaki, Hiroki Honda
  • Patent number: 6268627
    Abstract: In an access transistor formed on a silicon substrate, its drain region is formed of n− type and n+ type drain regions and its source region is formed of n− type and n+ type source regions. In a driver transistor, its source region is formed of n− type and n++ type source regions and its drain regions is formed of n− type and n+ type drain regions. The n+ +type source region is formed deeper than the n+ type drain region. Accordingly, a semiconductor device ensuring improvement in a static noise margin while suppressing increase in manufacturing cost is provided.
    Type: Grant
    Filed: November 24, 1998
    Date of Patent: July 31, 2001
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yoshiyuki Ishigaki, Yasuhiro Fujii