Patents by Inventor Shoichiro Kawashima

Shoichiro Kawashima 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: 20240079372
    Abstract: A semiconductor device is to be arranged adjacent to a cooler in a predetermined direction. The semiconductor device includes a semiconductor element having main electrodes on opposite faces thereof, first and second substrates interposing the semiconductor element therebetween, and a conductive spacer interposed between the second substrate and the semiconductor element. Each of the first and second substrates includes an insulating base member, a front-face metal body connected to a corresponding main electrode, and a back-face metal body. A thickness of a part of the semiconductor device on the first substrate side from the semiconductor element is referred to as T1, and a thickness of a part of the semiconductor device on the second substrate side from the semiconductor element is referred to as T2. A relationship of T1?T2 is satisfied.
    Type: Application
    Filed: November 8, 2023
    Publication date: March 7, 2024
    Inventors: SHOICHIRO OMAE, TOMOMI OKUMURA, TAKANORI KAWASHIMA
  • Publication number: 20150235689
    Abstract: A semiconductor memory device includes: a memory cell array including a memory cell, which includes a ferroelectric capacitor and an access transistor which is a first conductive type transistor formed in a second conductive type well and includes a source or a drain connected to one electrode of the ferroelectric capacitor; and a control circuit which controls a potential applied to the second conductive type well. The control circuit applies a fixed potential to another electrode of the ferroelectric capacitor and applies a second potential being a forward voltage with respect to a junction between the first conductive type source and drain and the second conductive type well when erasing data in the memory cell, and applies a third potential not being the forward voltage with respect to the junction between the first conductive type source and drain and the second conductive type well in a normal operation.
    Type: Application
    Filed: January 21, 2015
    Publication date: August 20, 2015
    Inventor: Shoichiro KAWASHIMA
  • Patent number: 9093168
    Abstract: A nonvolatile latch circuit includes: a latch circuit part; a charge absorption circuit part; and a first ferroelectric capacitor having a first electrode connected to a plate line and a second electrode connected to the charge absorption circuit part, wherein when information is read from the first ferroelectric capacitor to the latch circuit part, the plate line is operated to cause the charge absorption circuit part to absorb at least part of charges outputted from the first ferroelectric capacitor so as to suppress variation in potential of the second electrode of the first ferroelectric capacitor.
    Type: Grant
    Filed: February 21, 2013
    Date of Patent: July 28, 2015
    Assignee: FUJITSU SEMICONDUCTOR LIMITED
    Inventor: Shoichiro Kawashima
  • Patent number: 8767504
    Abstract: An activate signal generating circuit, to which a first and a second activate signals which are pulse signals are applied, and which generates an internal activate signal, has a first delay element. The internal activate signal is activated based on timings of front (active transient) edges of the first and second activate signals. When a timing of a rear (inactive transient) edge of the first activate signal is earlier than a timing of a rear edge of the second activate signal, the internal activate signal goes inactivate based on the timing of the rear edge of the first activate signal, and when the timing of the rear edge of the first activate signal is later than the timing of the rear edge of the second activate signal, the internal activate signal goes inactivate after a predetermined delay time based on a delay time of the first delay element.
    Type: Grant
    Filed: December 27, 2012
    Date of Patent: July 1, 2014
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Shoichiro Kawashima
  • Patent number: 8665628
    Abstract: A ferroelectric memory device has word, bit, plate lines; memory cells having access gate and ferroelectric capacitor; latch amplifier for latching stored data; and write amplifier for driving bit lines according to write data. The bit lines are precharged to a reference potential before an active period. In active period, at a first time, selected word line and plate line are driven to a high-level potential so that ferroelectric capacitor output electric charge to selected bit line, and at a second time, selected bit line is brought to reference potential regardless of write data so that first data is written to selected memory cell, and at a third time, plate line is driven to reference potential and is maintained; and in a precharge period, the write amplifier drives selected bit line to high-level potential according to write data so that second data is written to selected memory cell.
    Type: Grant
    Filed: August 19, 2011
    Date of Patent: March 4, 2014
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Shoichiro Kawashima
  • Patent number: 8542041
    Abstract: A first transistor has one end and a gate coupled to a first power supply line and other end coupled to a first node. A second transistor has a gate coupled to a second node, one end coupled to the first node, and other end coupled to a third node. A third transistor has one end coupled to a second power supply line, a gate coupled to a fourth node, and other end coupled to the third node. A first bias voltage generation circuit supplies a first bias voltage to the second node. A second bias voltage generation circuit supplies a second bias voltage to the fourth node. Accordingly, the power supply voltage at which the third node is changed from a certain level to another level is set high, and an internal node in a semiconductor device is securely initialized when the power supply voltage is decreased.
    Type: Grant
    Filed: April 6, 2010
    Date of Patent: September 24, 2013
    Assignee: Fujitsu Semiconductor Limited
    Inventors: Mitsuhiro Ogai, Hirokazu Yamazaki, Keizo Morita, Kazuaki Yamane, Yasuhiro Fujii, Kazuaki Takai, Shoichiro Kawashima
  • Publication number: 20130229849
    Abstract: A nonvolatile latch circuit includes: a latch circuit part; a charge absorption circuit part; and a first ferroelectric capacitor having a first electrode connected to a plate line and a second electrode connected to the charge absorption circuit part, wherein when information is read from the first ferroelectric capacitor to the latch circuit part, the plate line is operated to cause the charge absorption circuit part to absorb at least part of charges outputted from the first ferroelectric capacitor so as to suppress variation in potential of the second electrode of the first ferroelectric capacitor.
    Type: Application
    Filed: February 21, 2013
    Publication date: September 5, 2013
    Applicant: FUJITSU SEMICONDUCTOR LIMITED
    Inventor: Shoichiro KAWASHIMA
  • Publication number: 20120127776
    Abstract: A ferroelectric memory device has word, bit, plate lines; memory cells having access gate and ferroelectric capacitor; latch amplifier for latching stored data; and write amplifier for driving bit lines according to write data. The bit lines are precharged to a reference potential before an active period. In active period, at a first time, selected word line and plate line are driven to a high-level potential so that ferroelectric capacitor output electric charge to selected bit line, and at a second time, selected bit line is brought to reference potential regardless of write data so that first data is written to selected memory cell, and at a third time, plate line is driven to reference potential and is maintained; and in a precharge period, the write amplifier drives selected bit line to high-level potential according to write data so that second data is written to selected memory cell.
    Type: Application
    Filed: August 19, 2011
    Publication date: May 24, 2012
    Applicant: FUJITSU SEMICONDUCTOR LIMITED
    Inventor: Shoichiro KAWASHIMA
  • Publication number: 20100253419
    Abstract: A first transistor has one end and a gate coupled to a first power supply line and other end coupled to a first node. A second transistor has a gate coupled to a second node, one end coupled to the first node, and other end coupled to a third node. A third transistor has one end coupled to a second power supply line, a gate coupled to a fourth node, and other end coupled to the third node. A first bias voltage generation circuit supplies a first bias voltage to the second node. A second bias voltage generation circuit supplies a second bias voltage to the fourth node. Accordingly, the power supply voltage at which the third node is changed from a certain level to another level is set high, and an internal node in a semiconductor device is securely initialized when the power supply voltage is decreased.
    Type: Application
    Filed: April 6, 2010
    Publication date: October 7, 2010
    Applicant: FUJITSU MICROELECTRONICS LIMITED
    Inventors: Mitsuhiro OGAI, Hirokazu Yamazaki, Keizo Morita, Kazuaki Yamane, Yasuhiro Fujii, Kazuaki Takai, Shoichiro Kawashima
  • Patent number: 7729181
    Abstract: A semiconductor storage device comprises of a memory cell connected to a plate line and a bit line, a potential shift circuit which is connected to a bit line, temporarily changes in output voltage corresponding to the voltage change of the bit line when a voltage is applied to the plate line, a charge transfer circuit for transferring charge stored on the potential shift circuit corresponding to the temporary output voltage change of the potential shift circuit, and a charge accumulation circuit for generating a read voltage from a memory cell after accumulating the transferred charge.
    Type: Grant
    Filed: January 17, 2007
    Date of Patent: June 1, 2010
    Assignee: Fujitsu Microelectronics Limited
    Inventors: Keizo Morita, Shoichiro Kawashima
  • Publication number: 20090168577
    Abstract: A semiconductor storage device comprises of a memory cell connected to a plate line and a bit line, a potential shift circuit which is connected to a bit line, temporarily changes in output voltage corresponding to the voltage change of the bit line when a voltage is applied to the plate line, and then outputs a voltage before the application of the voltage to the plate line, a charge transfer circuit for transferring charge stored on the potential shift circuit corresponding to the temporary output voltage change of the potential shift circuit, and a charge accumulation circuit for generating a read voltage from a memory cell after accumulating the transferred charge.
    Type: Application
    Filed: March 5, 2009
    Publication date: July 2, 2009
    Applicant: FUJITSU LIMITED
    Inventors: Keizo Morita, Shoichiro Kawashima
  • Patent number: 7525846
    Abstract: A memory device includes a memory cell having a capacitor for accumulating electric charges in accordance with the logic of data, a bit line connected to the memory cell, a charge transfer circuit for transferring the electric charges in the bit line to an output node, a dummy memory cell connected to the bit line, and a control circuit for controlling the charge transfer ability of the charge transfer circuit in accordance with the change in the voltage of the bit line.
    Type: Grant
    Filed: July 13, 2006
    Date of Patent: April 28, 2009
    Assignee: Fujitsu Microelectronics Limited
    Inventors: Keizo Morita, Shoichiro Kawashima
  • Patent number: 7483287
    Abstract: A bit line is connected to a charge storing circuit through a charge transferring circuit. A control circuit controls charge transferability of the charge transferring circuit according to a change in the voltage of the bit line resulting from a charge read out from a memory cell. A leakage controlling circuit lowers the charge transferability of the charge transferring circuit in a read operation temporarily before the charge is read out to the bit line. The leakage controlling circuit makes it possible to avoid charge transfer between the charge storing circuit and the bit line before data is read from the memory cell. The charge storing circuit can thus generate a read voltage sufficient for a read circuit to operate with, in accordance with the logical value of the data stored in the memory cell.
    Type: Grant
    Filed: April 26, 2007
    Date of Patent: January 27, 2009
    Assignee: Fujitsu Microelectronics Limited
    Inventors: Isao Fukushi, Keizo Morita, Shoichiro Kawashima
  • Publication number: 20080055960
    Abstract: A semiconductor storage device comprises of a memory cell connected to a plate line and a bit line, a potential shift circuit which is connected to a bit line, temporarily changes in output voltage corresponding to the voltage change of the bit line when a voltage is applied to the plate line, and then outputs a voltage before the application of the voltage to the plate line, a charge transfer circuit for transferring charge stored on the potential shift circuit corresponding to the temporary output voltage change of the potential shift circuit, and a charge accumulation circuit for generating a read voltage from a memory cell after accumulating the transferred charge.
    Type: Application
    Filed: January 17, 2007
    Publication date: March 6, 2008
    Inventors: Keizo Morita, Shoichiro Kawashima
  • Publication number: 20070217250
    Abstract: There is provided a memory device including a memory cell having a capacitor for accumulating electric charges in accordance with the logic of data, a bit line connected to the memory cell, a charge transfer circuit for transferring the electric charges in the bit line to an output node, a dummy memory cell connected to the bit line, and a control circuit for controlling the charge transfer ability of the charge transfer circuit in accordance with the change in the voltage of the bit line.
    Type: Application
    Filed: July 13, 2006
    Publication date: September 20, 2007
    Inventors: Keizo Morita, Shoichiro Kawashima
  • Publication number: 20070195579
    Abstract: A bit line is connected to a charge storing circuit through a charge transferring circuit. A control circuit controls charge transferability of the charge transferring circuit according to a change in the voltage of the bit line resulting from a charge read out from a memory cell. A leakage controlling circuit lowers the charge transferability of the charge transferring circuit in a read operation temporarily before the charge is read out to the bit line. The leakage controlling circuit makes it possible to avoid charge transfer between the charge storing circuit and the bit line before data is read from the memory cell. The charge storing circuit can thus generate a read voltage sufficient for a read circuit to operate with, in accordance with the logical value of the data stored in the memory cell.
    Type: Application
    Filed: April 26, 2007
    Publication date: August 23, 2007
    Inventors: Isao Fukushi, Keizo Morita, Shoichiro Kawashima
  • Patent number: 7227769
    Abstract: A bit line is connected to a charge storing circuit through a charge transferring circuit. A control circuit controls charge transferability of the charge transferring circuit according to a change in the voltage of the bit line resulting from a charge read out from a memory cell. A leakage controlling circuit lowers the charge transferability of the charge transferring circuit in a read operation temporarily before the charge is read out to the bit line. The leakage controlling circuit makes it possible to avoid charge transfer between the charge storing circuit and the bit line before data is read from the memory cell. The charge storing circuit can thus generate a read voltage sufficient for a read circuit to operate with, in accordance with the logical value of the data stored in the memory cell.
    Type: Grant
    Filed: March 7, 2005
    Date of Patent: June 5, 2007
    Assignee: Fujitsu Limited
    Inventors: Isao Fukushi, Keizo Morita, Shoichiro Kawashima
  • Patent number: 7212430
    Abstract: A ferroelectric memory has a plurality of memory cells respectively having a cell transistor and ferroelectric capacitor whose one terminal is connected with the cell transistor, a plurality of word lines respectively connected with said cell transistor, a plurality of plate lines connected with the other terminal of said ferroelectric capacitor and intersecting with said word lines, a plurality of local bit lines connected with said cell transistors, and a global bit line that is selectively connected with local bit lines. Furthermore, the ferroelectric memory has a sensing amplifier unit that detects the amount of charging of the local bit lines from said memory cells while maintaining the potential of the local bit lines at a potential equivalent to the non-selected plate lines, during reading.
    Type: Grant
    Filed: May 23, 2005
    Date of Patent: May 1, 2007
    Assignee: Fujitsu Limited
    Inventors: Isao Fukushi, Shoichiro Kawashima
  • Publication number: 20060146590
    Abstract: A ferroelectric memory has a plurality of memory cells respectively having a cell transistor and ferroelectric capacitor whose one terminal is connected with the cell transistor, a plurality of word lines respectively connected with said cell transistor, a plurality of plate lines connected with the other terminal of said ferroelectric capacitor and intersecting with said word lines, a plurality of local bit lines connected with said cell transistors, and a global bit line that is selectively connected with local bit lines. Furthermore, the ferroelectric memory has a sensing amplifier unit that detects the amount of charging of the local bit lines from said memory cells while maintaining the potential of the local bit lines at a potential equivalent to the non-selected plate lines, during reading.
    Type: Application
    Filed: May 23, 2005
    Publication date: July 6, 2006
    Inventors: Isao Fukushi, Shoichiro Kawashima
  • Patent number: 7012829
    Abstract: A bit line is connected, via a first pMOS transistor, to a first node whose potential is set at a prescribed negative voltage in advance. The gate voltage of the first pMOS transistor is set at a constant voltage that is slightly lower than its threshold voltage. During a read operation, a current that flows into the bit line from a memory cell in accordance with a residual dielectric polarization value of a ferroelectric capacitor always leaks to the first node, whereby the potential of the first node increases. The logical value of data stored in the memory cell is judged on the basis of a voltage increase at the first node. Since no control circuit for keeping the potential of the first node at the ground potential during a read operation is necessary, the layout size and the power consumption of a ferroelectric memory can be decreased.
    Type: Grant
    Filed: February 7, 2005
    Date of Patent: March 14, 2006
    Assignee: Fujitsu Limited
    Inventors: Shoichiro Kawashima, Toru Endo, Tomohisa Hirayama