Patents by Inventor Makoto Yabuuchi

Makoto Yabuuchi 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: 20160240246
    Abstract: A semiconductor storage device provided can increase a write margin and suppress increase of a chip area. The semiconductor storage device includes plural memory cells arranged in a matrix; plural bit-line pairs arranged corresponding to each column of the memory cells; a write driver circuit which transmits data to a bit-line pair of a selected column according to write data; and a write assist circuit which drives a bit line on a low potential side of the bit-line pair of a selected column to a negative voltage level. The write assist circuit includes first signal wiring; a first driver circuit which drives the first signal wiring according to a control signal; and second signal wiring which is coupled to the bit line on the low-potential side and generates a negative voltage by the driving of the first driver circuit, based on inter-wire coupling capacitance with the first signal wiring.
    Type: Application
    Filed: April 21, 2016
    Publication date: August 18, 2016
    Inventors: Toshiaki SANO, Ken SHIBATA, Shinji TANAKA, Makoto YABUUCHI, Noriaki MAEDA
  • Publication number: 20160172023
    Abstract: In a semiconductor memory device, static memory cells are arranged in rows and columns, word lines correspond to respective memory cell rows, and word line drivers drive correspond to word lines. Cell power supply lines correspond to respective memory cell columns and are coupled to cell power supply nodes of a memory cell in a corresponding column. Down power supply lines are arranged corresponding to respective memory cell columns, maintained at ground voltage in data reading and rendered electrically floating in data writing. Write assist elements are arranged corresponding to the cell power supply lines, and according to a write column instruction signal for stopping supply of a cell power supply voltage to the cell power supply line in a selected column, and for coupling the cell power supply line arranged corresponding to the selected column at least to the down power supply line on the corresponding column.
    Type: Application
    Filed: February 24, 2016
    Publication date: June 16, 2016
    Applicant: Renesas Electronics Corporation
    Inventors: Koji NII, Shigeki OHBAYASHI, Yasumasa TSUKAMOTO, Makoto YABUUCHI
  • Patent number: 9349438
    Abstract: A semiconductor storage device provided can increase a write margin and suppress increase of a chip area. The semiconductor storage device includes plural memory cells arranged in a matrix; plural bit-line pairs arranged corresponding to each column of the memory cells; a write driver circuit which transmits data to a bit-line pair of a selected column according to write data; and a write assist circuit which drives a bit line on a low potential side of the bit-line pair of a selected column to a negative voltage level. The write assist circuit includes first signal wiring; a first driver circuit which drives the first signal wiring according to a control signal; and second signal wiring which is coupled to the bit line on the low-potential side and generates a negative voltage by the driving of the first driver circuit, based on inter-wire coupling capacitance with the first signal wiring.
    Type: Grant
    Filed: March 14, 2015
    Date of Patent: May 24, 2016
    Assignee: Renesas Electronics Corporation
    Inventors: Toshiaki Sano, Ken Shibata, Shinji Tanaka, Makoto Yabuuchi, Noriaki Maeda
  • Publication number: 20160133315
    Abstract: A semiconductor device with a memory unit of which the variations in the operation timing are reduced is provided. For example, the semiconductor device is provided with dummy bit lines which are arranged collaterally with a proper bit line, and column direction load circuits which are sequentially coupled to the dummy bit lines. Each column direction load circuit is provided with plural NMOS transistors fixed to an off state, predetermined ones of which have the source and the drain suitably coupled to any of the dummy bit lines. Load capacitance accompanying diffusion layer capacitance of the predetermined NMOS transistors is added to the dummy bit lines, and corresponding to the load capacitance, the delay time from a decode activation signal to a dummy bit line signal is set up. The dummy bit line signal is employed when setting the start-up timing of a sense amplifier.
    Type: Application
    Filed: December 28, 2015
    Publication date: May 12, 2016
    Applicant: Renesas Electronics Corporation
    Inventors: Shinji TANAKA, Makoto YABUUCHI, Yuta YOSHIDA
  • Patent number: 9299418
    Abstract: In a semiconductor memory device, static memory cells are arranged in rows and columns, word lines correspond to respective memory cell rows, and word line drivers drive correspond to word lines. Cell power supply lines correspond to respective memory cell columns and are coupled to cell power supply nodes of a memory cell in a corresponding column. Down power supply lines are arranged corresponding to respective memory cell columns, maintained at ground voltage in data reading and rendered electrically floating in data writing. Write assist elements are arranged corresponding to the cell power supply lines, and according to a write column instruction signal for stopping supply of a cell power supply voltage to the cell power supply line in a selected column, and for coupling the cell power supply line arranged corresponding to the selected column at least to the down power supply line on the corresponding column.
    Type: Grant
    Filed: April 28, 2014
    Date of Patent: March 29, 2016
    Assignee: RENESAS ELECTRONICS CORPORATION
    Inventors: Koji Nii, Shigeki Ohbayashi, Yasumasa Tsukamoto, Makoto Yabuuchi
  • Patent number: 9281017
    Abstract: A semiconductor device with a memory unit of which the variations in the operation timing are reduced is provided. For example, the semiconductor device is provided with dummy bit lines which are arranged collaterally with a proper bit line, and column direction load circuits which are sequentially coupled to the dummy bit lines. Each column direction load circuit is provided with plural NMOS transistors fixed to an off state, predetermined ones of which have the source and the drain suitably coupled to any of the dummy bit lines. Load capacitance accompanying diffusion layer capacitance of the predetermined NMOS transistors is added to the dummy bit lines, and corresponding to the load capacitance, the delay time from a decode activation signal to a dummy bit line signal is set up. The dummy bit line signal is employed when setting the start-up timing of a sense amplifier.
    Type: Grant
    Filed: July 1, 2014
    Date of Patent: March 8, 2016
    Assignee: Renesas Electronics Corporation
    Inventors: Shinji Tanaka, Makoto Yabuuchi, Yuta Yoshida
  • Publication number: 20160049395
    Abstract: An area of a semiconductor device having a FINFET can be reduced. The drain regions of an n-channel FINFET and a p-channel FINFET are extracted by two second local interconnects from a second Y gird between a gate electrode and a dummy gate adjacent thereto, to a third Y grid adjacent to the second Y gird. These second local interconnects are connected by a first local interconnect extending in the X direction in the third Y grid. According to such a cell layout, although the number of grids is increased by one because of the arrangement of the first local interconnect, the length in the X direction can be reduced. As a result, the cell area of the unit cell can be reduced while a space between the first and second local interconnects is secured.
    Type: Application
    Filed: August 14, 2015
    Publication date: February 18, 2016
    Applicant: Renesas Electronics Corporation
    Inventors: Takeshi OKAGAKI, Koji SHIBUTANI, Makoto YABUUCHI, Nobuhiro TSUDA
  • Patent number: 9251862
    Abstract: A semiconductor device with a memory unit of which the variations in the operation timing are reduced is provided. For example, the semiconductor device is provided with dummy bit lines which are arranged collaterally with a proper bit line, and column direction load circuits which are sequentially coupled to the dummy bit lines. Each column direction load circuit is provided with plural NMOS transistors fixed to an off state, predetermined ones of which have the source and the drain suitably coupled to any of the dummy bit lines. Load capacitance accompanying diffusion layer capacitance of the predetermined NMOS transistors is added to the dummy bit lines, and corresponding to the load capacitance, the delay time from a decode activation signal to a dummy bit line signal is set up. The dummy bit line signal is employed when setting the start-up timing of a sense amplifier.
    Type: Grant
    Filed: July 1, 2014
    Date of Patent: February 2, 2016
    Assignee: Renesas Electronics Corporation
    Inventors: Shinji Tanaka, Makoto Yabuuchi, Yuta Yoshida
  • Publication number: 20150279454
    Abstract: A semiconductor storage device provided can increase a write margin and suppress increase of a chip area. The semiconductor storage device includes plural memory cells arranged in a matrix; plural bit-line pairs arranged corresponding to each column of the memory cells; a write driver circuit which transmits data to a bit-line pair of a selected column according to write data; and a write assist circuit which drives a bit line on a low potential side of the bit-line pair of a selected column to a negative voltage level. The write assist circuit includes first signal wiring; a first driver circuit which drives the first signal wiring according to a control signal; and second signal wiring which is coupled to the bit line on the low-potential side and generates a negative voltage by the driving of the first driver circuit, based on inter-wire coupling capacitance with the first signal wiring.
    Type: Application
    Filed: March 14, 2015
    Publication date: October 1, 2015
    Inventors: Toshiaki SANO, Ken SHIBATA, Shinji TANAKA, Makoto YABUUCHI, Noriaki MAEDA
  • Publication number: 20150098268
    Abstract: The disclosed invention provides an SRAM capable of stably generating a PUF-ID without having to be powered on/off under control. The SRAM including a plurality of write ports is provided with a plurality of word lines, each transferring write data from each of the write ports to one memory cell. Timing to negate at least two word lines (AWL, BWL), respectively coupled to two write ports, among the word lines is synchronized. Because synchronicity of writing different values to the memory cell is assured, by using a large number of such memory cells, it is possible to stably generate a PUF-ID without power on/off control.
    Type: Application
    Filed: September 30, 2014
    Publication date: April 9, 2015
    Inventor: Makoto YABUUCHI
  • Publication number: 20150078058
    Abstract: Provided is a semiconductor storage device including: first memory cells; first word lines; first bit lines; a first common bit line; second memory cells; second word lines; second bit lines; a second common bit line; a first selection circuit that connects the first common bit line to a first bit line selected from the first bit lines; a second selection circuit that connects the second common bit line to a second bit line selected from the second bit lines; a word line driver that activates any one of the first and second word lines; a reference current supply unit that supplies a reference current to a common bit line among the first and second common bit lines, the common bit line not being electrically connected to a data read target memory cell; and a sense amplifier that amplifies a potential difference between the first and second common bit lines.
    Type: Application
    Filed: August 7, 2014
    Publication date: March 19, 2015
    Applicant: Renesas Electronics Corporation
    Inventor: Makoto YABUUCHI
  • Publication number: 20150070976
    Abstract: There is provided, for example, a write assist circuit for controlling the voltage level of a memory cell power supply line coupled to an SRAM memory cell to be written in the write operation. The write assist circuit reduces the voltage level of the memory cell power supply line to a predetermined voltage level, in response to a write assist enable signal that is enabled in the write operation. At the same time, the write assist circuit controls the reduction speed of the voltage level of the memory cell power supply line, according to the pulse width of a write assist pulse signal. The pulse width of the write assist pulse signal is defined in such a way that the greater the number of rows (or the longer the length of the memory cell power supply line), the greater the pulse width.
    Type: Application
    Filed: November 18, 2014
    Publication date: March 12, 2015
    Inventor: Makoto Yabuuchi
  • Publication number: 20150029784
    Abstract: There is provided a semiconductor integrated circuit device that can generate a unique ID with the suppression of overhead. When a unique ID is generated, the potential of a word line of a memory cell in an SRAM is raised above the power supply voltage of the SRAM, and then lowered below the power supply voltage of the SRAM. When the potential of the word line is above the power supply voltage of the SRAM, the same data is supplied to both the bit lines of the memory cell. Thereby, the memory cell in the SRAM is put into an undefined state and then changed so as to hold data according to characteristics of elements or the like configuring the memory cell. In the manufacture of the SRAM, there occur variations in characteristics of elements or the like configuring the memory cell. Accordingly, the memory cell in the SRAM holds data according to variations occurring in the manufacture.
    Type: Application
    Filed: July 18, 2014
    Publication date: January 29, 2015
    Applicant: Renesas Electronics Corporation
    Inventors: Makoto YABUUCHI, Hidehiro FUJIWARA
  • Patent number: 8908418
    Abstract: There is provided, for example, a write assist circuit for controlling the voltage level of a memory cell power supply line coupled to an SRAM memory cell to be written in the write operation. The write assist circuit reduces the voltage level of the memory cell power supply line to a predetermined voltage level, in response to a write assist enable signal that is enabled in the write operation. At the same time, the write assist circuit controls the reduction speed of the voltage level of the memory cell power supply line, according to the pulse width of a write assist pulse signal. The pulse width of the write assist pulse signal is defined in such a way that the greater the number of rows (or the longer the length of the memory cell power supply line), the greater the pulse width.
    Type: Grant
    Filed: September 12, 2012
    Date of Patent: December 9, 2014
    Assignee: Renesas Electronics Corporation
    Inventor: Makoto Yabuuchi
  • Publication number: 20140313811
    Abstract: A semiconductor device with a memory unit of which the variations in the operation timing are reduced is provided. For example, the semiconductor device is provided with dummy bit lines which are arranged collaterally with a proper bit line, and column direction load circuits which are sequentially coupled to the dummy bit lines. Each column direction load circuit is provided with plural NMOS transistors fixed to an off state, predetermined ones of which have the source and the drain suitably coupled to any of the dummy bit lines. Load capacitance accompanying diffusion layer capacitance of the predetermined NMOS transistors is added to the dummy bit lines, and corresponding to the load capacitance, the delay time from a decode activation signal to a dummy bit line signal is set up. The dummy bit line signal is employed when setting the start-up timing of a sense amplifier.
    Type: Application
    Filed: July 1, 2014
    Publication date: October 23, 2014
    Inventors: Shinji TANAKA, Makoto Yabuuchi, Yuta Yoshida
  • Publication number: 20140293680
    Abstract: In a semiconductor memory device, static memory cells are arranged in rows and columns, word lines correspond to respective memory cell rows, and word line drivers drive correspond to word lines. Cell power supply lines correspond to respective memory cell columns and are coupled to cell power supply nodes of a memory cell in a corresponding column. Down power supply lines are arranged corresponding to respective memory cell columns, maintained at ground voltage in data reading and rendered electrically floating in data writing. Write assist elements are arranged corresponding to the cell power supply lines, and according to a write column instruction signal for stopping supply of a cell power supply voltage to the cell power supply line in a selected column, and for coupling the cell power supply line arranged corresponding to the selected column at least to the down power supply line on the corresponding column.
    Type: Application
    Filed: April 28, 2014
    Publication date: October 2, 2014
    Applicant: Renesas Electronics Corporation
    Inventors: Koji NII, Shigeki OHBAYASHI, Yasumasa TSUKAMOTO, Makoto YABUUCHI
  • Patent number: 8797781
    Abstract: A semiconductor device with a memory unit of which the variations in the operation timing are reduced is provided. For example, the semiconductor device is provided with dummy bit lines which are arranged collaterally with a proper bit line, and column direction load circuits which are sequentially coupled to the dummy bit lines. Each column direction load circuit is provided with plural NMOS transistors fixed to an off state, predetermined ones of which have the source and the drain suitably coupled to any of the dummy bit lines. Load capacitance accompanying diffusion layer capacitance of the predetermined NMOS transistors is added to the dummy bit lines, and corresponding to the load capacitance, the delay time from a decode activation signal to a dummy bit line signal is set up. The dummy bit line signal is employed when setting the start-up timing of a sense amplifier.
    Type: Grant
    Filed: September 13, 2013
    Date of Patent: August 5, 2014
    Assignee: Renesas Electronics Corporation
    Inventors: Shinji Tanaka, Makoto Yabuuchi, Yuta Yoshida
  • Publication number: 20140191338
    Abstract: In a region just below an access gate electrode in an SRAM memory cell, a second halo region is formed adjacent to a source-drain region and a first halo region is formed adjacent to a first source-drain region. In a region just below a drive gate electrode, a third halo region is formed adjacent to the third source-drain region and a fourth halo region is formed adjacent to a fourth source-drain region. The second halo region is set to have an impurity concentration higher than the impurity concentration of the first halo region. The third halo region is set to have an impurity concentration higher than the impurity concentration of the fourth halo region. The impurity concentration of the first halo region and the impurity concentration of the fourth halo region are different from each other.
    Type: Application
    Filed: July 29, 2011
    Publication date: July 10, 2014
    Applicant: RENESAS ELECTRONICS CORPORATION
    Inventors: Koji Nii, Makoto Yabuuchi, Yasumasa Tsukamoto, Kengo Masuda
  • Patent number: 8743645
    Abstract: In a semiconductor memory device, static memory cells are arranged in rows and columns, word lines correspond to respective memory cell rows, and word line drivers drive correspond to word lines. Cell power supply lines correspond to respective memory cell columns and are coupled to cell power supply nodes of a memory cell in a corresponding column. Down power supply lines are arranged corresponding to respective memory cell columns, maintained at ground voltage in data reading and rendered electrically floating in data writing. Write assist elements are arranged corresponding to the cell power supply lines, and according to a write column instruction signal for stopping supply of a cell power supply voltage to the cell power supply line in a selected column, and for coupling the cell power supply line arranged corresponding to the selected column at least to the down power supply line on the corresponding column.
    Type: Grant
    Filed: December 14, 2011
    Date of Patent: June 3, 2014
    Assignee: Renesas Electronics Corporation
    Inventors: Koji Nii, Shigeki Ohbayashi, Yasumasa Tsukamoto, Makoto Yabuuchi
  • Publication number: 20140070212
    Abstract: A semiconductor device having a capability of generating chip identification information includes: an SRAM macro having a plurality of memory cells arranged in rows and columns; a test address storage unit configured to store a test address; a self-diagnostic circuit configured to output the test address based on a result of confirmation of operation of the memory cell selected by the test address; and an identification information generation circuit configured to generate chip identification information based on the test address which is output by the self-diagnostic circuit.
    Type: Application
    Filed: September 10, 2013
    Publication date: March 13, 2014
    Applicant: RENESAS ELECTRONICS CORPORATION
    Inventors: Hidehiro FUJIWARA, Makoto YABUUCHI, Koji NII, Yoshikazu SAITO