Patents by Inventor Tomonori Sekiguchi

Tomonori Sekiguchi 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: 20100109756
    Abstract: A substrate voltage control technique that prevents the operating speed from being decreased and suppresses a leakage current due to a lower threshold voltage with respect to a low voltage use. Since a center value of the threshold voltages is detected by plural replica MOS transistors, and a substrate voltage is controlled to control a center value of the threshold voltages, thereby making it possible to satisfy a lower limit of the operating speed and an upper limit of a leakage current of the entire chip. On the other hand, the substrate voltage is dynamically controlled during the operation of the chip, thereby making it possible to decrease the center value of the threshold voltages when the chip operates to improve the speed, and to increase the center value of the threshold voltages after the operation of the chip to reduce the leakage current of the entire chip.
    Type: Application
    Filed: January 13, 2010
    Publication date: May 6, 2010
    Inventors: Hiroaki NAKAYA, Satoru AKIYAMA, Tomonori SEKIGUCHI, Riichiro TAKEMURA
  • Patent number: 7706208
    Abstract: If memory cell blocks are laid out in a conventional manner to create a memory chip with a capacity of an odd power of 2 by using memory cells whose aspect ratio is 1:2, the chip will take a 1:1 shape and become difficult to enclose in a package of a 1:2 shape. In addition, such conventional layout of memory cell blocks to form the 1:2 shape causes the area of a peripheral circuit region to be limited by the memory blocks, pads to be arranged collectively in the central section of the chip, and wiring to become dense during the enclosure of the chip in the package. In this invention, therefore, four memory blocks, BANK0, BANK1, BANK2, BANK3, BANK3, are constructed into an L shape and then these memory blocks are properly combined and arranged to construct a chip of nearly a 1:2 shape in terms of aspect ratio.
    Type: Grant
    Filed: January 15, 2009
    Date of Patent: April 27, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Riichiro Takemura, Tomonori Sekiguchi
  • Patent number: 7659769
    Abstract: A substrate voltage control technique that prevents the operating speed from being decreased and suppresses a leakage current due to a lower threshold voltage with respect to a low voltage use. Since a center value of the threshold voltages is detected by plural replica MOS transistors, and a substrate voltage is controlled to control a center value of the threshold voltages, thereby making it possible to satisfy a lower limit of the operating speed and an upper limit of a leakage current of the entire chip. On the other hand, the substrate voltage is dynamically controlled during the operation of the chip, thereby making it possible to decrease the center value of the threshold voltages when the chip operates to improve the speed, and to increase the center value of the threshold voltages after the operation of the chip to reduce the leakage current of the entire chip.
    Type: Grant
    Filed: June 29, 2007
    Date of Patent: February 9, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Hiroaki Nakaya, Satoru Akiyama, Tomonori Sekiguchi, Riichiro Takemura
  • Publication number: 20090323399
    Abstract: A semiconductor memory device (e.g. DRAM) is constituted of a memory cell array including a plurality of memory cells, a plurality of word line drivers, a plurality of sense amplifiers, and a plurality of dummy capacitors. The memory cells, each of which includes a transistor and a capacitor, are positioned at intersections between the word lines and the bit lines. The first electrodes of the capacitors are connected to the transistors in the memory cells. The first electrodes of the dummy capacitors are connected together and are supplied with a second potential (e.g. VDD or VSS). The second electrodes of the dummy capacitors are connected together with the second electrodes of the capacitors of the memory cells and are supplied with a first potential (e.g. VPL). The dummy capacitors serve as smoothing capacitances for the plate voltage VPL so as to reduce plate noise.
    Type: Application
    Filed: June 16, 2009
    Publication date: December 31, 2009
    Applicant: ELPIDA MEMORY, INC.
    Inventors: Kazuhiko KAJIGAYA, Soichiro Yoshida, Tomonori Sekiguchi, Riichiro Takemura, Yasutoshi Yamada
  • Patent number: 7633833
    Abstract: The semiconductor memory device according to the invention is provided with a first delay circuit block that generates a timing signal of a circuit block to be operated in column cycle time determined by an external input command cycle and a second delay circuit block the whole delay of which is controlled to be a difference between access time determined by an external clock and the latency and column cycle time. These delay circuit blocks are controlled so that the delay of each delay circuit is a suitable value in accordance with column latency and an operating frequency, and each delay is controlled corresponding to dispersion in a process and operating voltage and a change of operating temperature.
    Type: Grant
    Filed: February 9, 2008
    Date of Patent: December 15, 2009
    Assignees: Hitachi, Ltd., Elpida Memory, Inc.
    Inventors: Riichiro Takemura, Tomonori Sekiguchi, Satoru Akiyama, Hiroaki Nakaya, Masayuki Nakamura
  • Publication number: 20090273961
    Abstract: A technique for increasing rewriting current without increasing a power supply voltage and also reducing location dependency inside a memory array of a resistive state after the rewriting is provided in a resistance change memory in which the resistance value of a memory cell changes between logical values “1” and “0”. In the resistance change memory, bit lines are formed into a layered structure, the bit line select switches for connecting to the global bit line are provided at both ends of the local bit line, and a control method of the bit line select switches is changed in the writing and the reading, thereby realizing the optimum array configurations for each of them. More specifically, in the writing and the reading, two current paths are provided in parallel by turning ON the bit line select switches simultaneously.
    Type: Application
    Filed: April 25, 2009
    Publication date: November 5, 2009
    Inventors: Kazuo ONO, Riichiro Takemura, Tomonori Sekiguchi
  • Patent number: 7609572
    Abstract: In a semiconductor memory device, with respect to low voltage application, technique of controlling a gate voltage of a shared MOS transistor increasing sense speed and increasing data read speed by preventing data inversion caused by noise and reducing bit line capacitance during sensing is provided. By a shared MOS transistor gate voltage control circuit connecting a sense amplifier and a memory cell array, a shared MOS transistor gate voltage (SHR) is lowered in two stages and bit line capacitance to be amplified is reduced taking noise during the sensing into consideration so that the sense speed is increased. Therefore, a timing of activating a column selection signal can be hastened and as a result, data read time can be reduced.
    Type: Grant
    Filed: December 22, 2007
    Date of Patent: October 27, 2009
    Assignees: Hitachi, Ltd., Elpida Memory, Inc.
    Inventors: Hiroaki Nakaya, Riichiro Takemura, Satoru Akiyama, Tomonori Sekiguchi, Masayuki Nakamura, Shinichi Miyatake
  • Publication number: 20090262574
    Abstract: A highly reliable large capacity phase change memory module is realized. A semiconductor device according to the present invention includes a memory array having a structure in which a storage layer using a chalcogenide material and a memory cell constituted of a diode are stacked, and an initialization condition and a rewriting condition are changed in accordance with the layer where a selected memory cell is located. A current mirror circuit is selected in accordance with an operation, and at the same time, the initialization condition and the rewriting condition (here, reset condition) are changed in accordance with the operation by a control mechanism of the reset current in a voltage selection circuit and a current mirror circuit.
    Type: Application
    Filed: April 21, 2009
    Publication date: October 22, 2009
    Inventors: Satoru HANZAWA, Hitoshi Kume, Motoyasu Terao, Tomonori Sekiguchi, Makoto Saen
  • Publication number: 20090262568
    Abstract: A resistance variable memory reduces the nonuniformity of resistance values after programming, so that a rewrite operation can be performed on a memory cell at high speed. A reference resistor is connected in series with the resistance variable memory cell, and a sensor amplifier detects whether the potential at an intermediate node between the memory cell and the reference resistor exceeds a given threshold voltage, so as to stop the write operation based on a detection result.
    Type: Application
    Filed: July 11, 2008
    Publication date: October 22, 2009
    Inventors: KAZUO ONO, Riichiro Takemura, Tomonori Sekiguchi
  • Patent number: 7603592
    Abstract: A semiconductor memory device capable of achieving a sufficient operating margin without increasing an area penalty even in the case of miniaturization is provided. An error correction system composed of a data bit of 64 bits and a check bit of 9 bits is introduced to a memory array such as DRAM, and an error correction code circuit required therein is disposed near a sense amplifier array. In addition to normal memory arrays composed of such memory arrays, a redundant memory array having a sense amplifier array and an error correction code circuit adjacent thereto is provided in a chip. By this means, the error which occurs in the manufacture can be replaced. Also, the error correction code circuit corrects the error at the time of an activate command and stores the check bit at the time of a pre-charge command.
    Type: Grant
    Filed: July 31, 2006
    Date of Patent: October 13, 2009
    Assignees: Hitachi, Ltd., Elpida Memory, Inc.
    Inventors: Tomonori Sekiguchi, Riichiro Takemura, Satoru Akiyama, Satoru Hanzawa, Kazuhiko Kajigaya
  • Publication number: 20090251948
    Abstract: In a semiconductor memory device, a memory cell is connected with a local sense amplifier and a global sense amplifier via a local bit line and a global bit line. The local sense amplifier is a single-ended sense amplifier including a single MOS transistor, which detects a potential of the local bit line which varies when reading and writing data with the memory cell. The threshold voltage of the MOS transistor is monitored so as to produce a high-level write voltage and a low-level write voltage, which are corrected and shifted based on the monitoring result so as to properly perform a reload operation on the memory cell by the global local sense amplifier. Thus, it is possible to cancel out temperature-dependent variations of the threshold voltage and shifting of the threshold voltage due to dispersions of manufacturing processes.
    Type: Application
    Filed: April 1, 2009
    Publication date: October 8, 2009
    Applicant: Elpida Memory, Inc.
    Inventors: Kazuhiko Kajigaya, Soichiro Yoshida, Tomonori Sekiguchi, Riichiro Takemura, Yasutoshi Yamada
  • Patent number: 7582921
    Abstract: In a masking pattern (a) for patterning word and data lines, length is changed between adjacent word lines so as to be shifted from each other at their tips, and furthermore, the tip of each word line is cut obliquely. It is thus possible to prevent the resist pattern from separation and contact of adjacent patterns. Consequently, it is also possible to prevent break failures of patterned lines and short failures between those patterned lines.
    Type: Grant
    Filed: August 16, 2006
    Date of Patent: September 1, 2009
    Assignee: Hitachi, Ltd.
    Inventors: Tomonori Sekiguchi, Toshihiko Tanaka, Toshiaki Yamanaka, Takeshi Sakata, Katsutaka Kimura
  • Patent number: 7574648
    Abstract: When the miniaturization of a DRAM advances, the capacity of a cell capacitor decreases, and further the voltage of a data line is lowered, the amount of read signals remarkably lowers, errors are produced during readout, and the yield of chips lowers. To solve the above problems, the present invention provides a DRAM that: has an error correcting code circuit for each sub-array; detects and corrects errors with said error correcting code circuit in both the reading and writing operations; and further has rescue circuits in addition to said error correcting code circuits and replaces a defective cell caused by hard error with a redundant bit.
    Type: Grant
    Filed: August 2, 2005
    Date of Patent: August 11, 2009
    Assignee: Hitachi, Ltd.
    Inventors: Satoru Akiyama, Riichiro Takemura, Tomonori Sekiguchi
  • Publication number: 20090180343
    Abstract: A sense amplifier is constructed to reduce the occurrence of malfunctions in a memory read operation, and thus degraded chip yield, due to increased offset of the sense amplifier with further sealing down. The sense amplifier circuit is constructed with a plurality of pull-down circuits and a pull-up circuit, and a transistor in one of the plurality of pull-down circuits has a constant such as a channel length or a channel width larger than that of a transistor in another pull-down circuit. The pull-down circuit with a larger constant of a transistor is first activated, and then, the other pull-down circuit and the pull-up circuit are activated to perform the read operation.
    Type: Application
    Filed: January 12, 2009
    Publication date: July 16, 2009
    Inventors: Satoru AKIYAMA, Riichiro TAKEMURA, Takayuki KAWAHARA, Tomonori SEKIGUCHI
  • Publication number: 20090180341
    Abstract: Disclosed is a semiconductor device including a first clock generator that generates a first clock signal having a first period from an input clock signal, a second clock generator that generates a second clock signal having a second period from the input clock signal, and a timing generator that receives the first clock signal, the second clock signal, an activation signal from a command decoder and a selection signal for selecting the delay time from a timing register to produce a timing signal delayed as from activation of the activation signal by a delay equal to a sum of a time equal to a preset number m prescribed by the selection signal times the first period and a time equal to another preset number n prescribed by the selection signal times the second period. The timing register holds the values of m and n. These values are set in the timing register in an initialization sequence at the time of a mode register set command.
    Type: Application
    Filed: December 17, 2008
    Publication date: July 16, 2009
    Inventors: Akira Ide, Yasuhiro Takai, Tomonori Sekiguchi, Riichiro Takemura, Satoru Akiyama, Hiroaki Nakaya
  • Publication number: 20090175064
    Abstract: A semiconductor device includes a plurality of word lines, a plurality of bit lines, a plurality of memory cells provided at the intersections of the plurality of word lines and the plurality of bit lines and each of that includes a MIS transistor and a memory element, a decoder circuit for selecting a plurality of word lines, and a sense-amplifier circuit for determining information that is read from any of the plurality of memory cells to any of the plurality of bit lines, wherein a twist connector for switching the wiring order of the plurality of word lines is provided and level-stabilizing circuits, for supplying the potential level of a non-selected state to the plurality of word lines in the non-selected state are arranged in the area below the twist connector.
    Type: Application
    Filed: December 23, 2008
    Publication date: July 9, 2009
    Applicant: Elpida Memory, Inc.
    Inventors: Yasutoshi Yamada, Tomonori Sekiguchi, Riichiro Takemura, Kazuhiko Kajigaya
  • Publication number: 20090146716
    Abstract: A timing control circuit DLY1 receives clock signal CKa with period T1 and activation signal ACT and outputs fine timing signal FT with delay of m*T1+tda measured from the clock signal where m denotes a non-negative integer and tda denotes delay in the analog delay element. The timing control circuit DLY1 comprises a coarse delay circuit CD and a fine delay circuit FD. The coarse delay circuit CD comprises a counter for counting a rising edge of the clock signal CKa after receiving activation signal ACT and outputs coarse timing signal CT with delay of m*T1 measured from a rising edge of the clock signal CKa. The fine delay circuit FD comprises a plurality of analog delay elements and outputs fine delay timing signal FT with delay of tda measured from the coarse timing signal CT. Variation in delay of timing signal is reduced.
    Type: Application
    Filed: December 5, 2008
    Publication date: June 11, 2009
    Inventors: Akira Ide, Yasuhiro Takai, Akira Kotabe, Tomonori Sekiguchi, Riichiro Takemura, Satoru Akiyama
  • Publication number: 20090129136
    Abstract: If memory cell blocks are laid out in a conventional manner to create a memory chip with a capacity of an odd power of 2 by using memory cells whose aspect ratio is 1:2, the chip will take a 1:1 shape and become difficult to enclose in a package of a 1:2 shape. In addition, such conventional layout of memory cell blocks to form the 1:2 shape causes the area of a peripheral circuit region to be limited by the memory blocks, pads to be arranged collectively in the central section of the chip, and wiring to become dense during the enclosure of the chip in the package. In this invention, therefore, four memory blocks, BANK0, BANK1, BANK2, BANK3, BANK3, are constructed into an L shape and then these memory blocks are properly combined and arranged to construct a chip of nearly a 1:2 shape in terms of aspect ratio.
    Type: Application
    Filed: January 15, 2009
    Publication date: May 21, 2009
    Inventors: Riichiro TAKEMURA, Tomonori SEKIGUCHI
  • Publication number: 20090129173
    Abstract: The semiconductor integrated circuit device includes: a first latch which can hold an output signal of the X decoder and transfer the signal to the word driver in a post stage subsequent to the X decoder; a second latch which can hold an output signal of the Y decoder and transfer the signal to the column multiplexer in the post stage subsequent to the Y decoder; and a third latch which can hold an output signal of the sense amplifier and transfer the signal to the output buffer in the post stage subsequent to the sense amplifier. The structure makes it possible to pipeline-control a series of processes for reading data stored in the non-volatile semiconductor memory, and enables low-latency access even with access requests from CPUs conflicting.
    Type: Application
    Filed: November 12, 2008
    Publication date: May 21, 2009
    Inventors: Shinya KAJIYAMA, Yutaka Shinagawa, Makoto Mizuno, Hideo Kasai, Takao Watanabe, Riichiro Takemura, Tomonori Sekiguchi
  • Publication number: 20090116363
    Abstract: In an information memory apparatus having minute areas for storing information arranged in x, y and z directions three-dimensionally, parallel rays are irradiated to a memory area MA in a direction perpendicular to a z-axis to take projection images of the memory area MA while rotating the memory area MA around the z-axis little by little. The light rays irradiated at this time have a size which covers at least a direction of an x-y plane of the memory area. A computation unit PU finds data and addresses of minute areas distributed three-dimensionally by performing computation based upon the principle of computer tomography on the projection images. As for data writing, a change is given to optical transmissivity or light emission characteristics by irradiating laser light focused by a lens OL placed outside the memory area to a desired minute area and causing heat denaturation within the pertinent minute area.
    Type: Application
    Filed: October 30, 2008
    Publication date: May 7, 2009
    Inventors: Takao WATANABE, Toshimichi Shintani, Takeshi Maeda, Akemi Hirotsune, Tomonori Sekiguchi