Patents by Inventor Atsushi Narazaki

Atsushi Narazaki 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: 20110298485
    Abstract: A method of testing a semiconductor device includes a conductive foreign matter test step of measuring the resistance value between the first and second conductive patterns to determine whether conductive foreign matter is present between the first and second conductive patterns, a first open circuit test step of measuring the resistance value between two points on the first conductive pattern to determine whether there is an open circuit in the first conductive pattern, and a second open circuit test step of measuring the resistance value between two points on the second conductive pattern to determine whether there is an open circuit in the second conductive pattern. The measurement of the resistance value in each of the test steps is accomplished by pressing probes vertically against the first conductive pattern or the second conductive pattern or both.
    Type: Application
    Filed: March 8, 2011
    Publication date: December 8, 2011
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventor: Atsushi NARAZAKI
  • Publication number: 20110244604
    Abstract: A semiconductor wafer having IGBT elements and transistors formed on a surface thereof is prepared. Electron beams are emitted all over the surface of the semiconductor wafer. Recombination centers are formed in the IGBT elements and the transistors. ON voltages of the transistors are measured by a measurement device, and lifetimes defined in the IGBT elements and the transistors are recovered by a prescribed annealing treatment. When the lifetimes are recovered, a control device controls an annealing treatment amount in the annealing treatment based on the measured ON voltages of the transistors such that ON voltages of the IGBT elements are each equal to a desired ON voltage. Variations in the ON voltages of a plurality of IGBT elements obtained from the semiconductor wafer are reduced.
    Type: Application
    Filed: January 21, 2011
    Publication date: October 6, 2011
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Atsushi Narazaki, Yukio Matsushita, Masashi Osaka, Shunsuke Sakamoto
  • Publication number: 20110233715
    Abstract: A semiconductor device according to the present invention includes: a cell active region including a p-base layer being an active layer of a second conductivity type that is diffused above a high concentration n-type substrate being a semiconductor substrate of a first conductivity type; and a p-well layer being a first well region of the second conductivity type having a ring shape, which is adjacent to the p-base layer, is diffused above the high concentration n-type substrate so as to surround the cell active region, and serves as a main junction part of a guard ring structure, wherein in a region on a surface of the p-well layer other than both ends, a trench region that is a ring-shaped recess having a tapered side surface is formed along the ring shape of the p-well layer 4, the side surface widening upward.
    Type: Application
    Filed: October 19, 2010
    Publication date: September 29, 2011
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventor: Atsushi NARAZAKI
  • Publication number: 20110220914
    Abstract: A method of manufacturing a power semiconductor device according to the present invention includes the steps of: (a) forming a silicon nitride film on a semiconductor substrate; (b) after the step (a), forming a ring-shaped trench along a peripheral portion of the semiconductor substrate 6; (c) forming a first silicon oxide film on an inner surface of the trench; (d) after the step (c), forming a second silicon oxide film on an entire surface of the semiconductor substrate to bury the trench; (e) planarizing the second silicon oxide film by using the silicon nitride film as a stopper; and (f) forming a third silicon oxide film in a region in which the silicon nitride film is removed.
    Type: Application
    Filed: December 7, 2010
    Publication date: September 15, 2011
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Ryoichi Fujii, Shigeto Honda, Atsushi Narazaki, Kaoru Motonami
  • Publication number: 20110089522
    Abstract: A semiconductor wafer has a main surface. A main chip region is formed on the main surface. A sub-chip region is smaller in area than the main chip region, and positioned on an edge side of the semiconductor wafer relative to the main chip region. The sub-chip region is identical to the main chip region in design pattern. Accordingly, a semiconductor device in which occurrence of a pattern failure at the edge of the wafer can be prevented when chips are arranged in the surface of the semiconductor wafer and a method of manufacturing the same can be obtained.
    Type: Application
    Filed: August 2, 2010
    Publication date: April 21, 2011
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventor: Atsushi NARAZAKI
  • Publication number: 20110089487
    Abstract: A semiconductor device includes a base layer that has a first conductivity type, a source layer that is formed on the base layer and has a second conductivity type, and an insulating film that is formed on the source layer. The semiconductor device further includes a plurality of gate structures that penetrate the base layer, and a plurality of conductive parts that penetrate the insulating film and the source layer and electrically connect the source layer and the base layer to each other. The gate structures are formed in a strip shape in plan view. Parts in which the conductive portion is connected to the base layer are formed in a stripe shape in plan view, and are formed between the gate structures. Further, a dimension of the part in which the source layer and the base layer are in contact with each other between the gate structure and the conductive portion is 0.36 ?m or more.
    Type: Application
    Filed: July 15, 2010
    Publication date: April 21, 2011
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Kazunari NAKATA, Atsushi Narazaki, Shigeto Honda, Kaoru Motonami
  • Publication number: 20110084354
    Abstract: In a semiconductor device according to the present invention, an electrode layer and a recessed part are formed on a surface of a semiconductor substrate. Further, in the semiconductor substrate, a RESURF layer that is in contact with a bottom surface of the recessed part and the electrode layer is formed. In addition, an insulating film is formed on an upper surface of the semiconductor substrate so as to fill the recessed part. Moreover, a field plate electrode is formed on the insulating film above the recessed part.
    Type: Application
    Filed: July 28, 2010
    Publication date: April 14, 2011
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Shigeto Honda, Atsushi Narazaki, Kaoru Motonami
  • Publication number: 20110059612
    Abstract: A passivation film having a predetermined width from an outer peripheral end portion toward an inner side and extending along the outer peripheral end portion is formed on a front surface of a semiconductor substrate. An outer peripheral end surface orthogonal to the front surface and a rear surface is formed by grinding the outer peripheral end portion of the semiconductor substrate. A thickness of the semiconductor substrate is reduced to a predetermined thickness by grinding the rear surface. The ground rear surface is etched by discharging a mixed acid onto the rear surface while rotating the semiconductor substrate with the rear surface facing upward, to remove a fracture layer. Thereby, chipping or cracking of the semiconductor substrate is suppressed.
    Type: Application
    Filed: June 30, 2010
    Publication date: March 10, 2011
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Kazunari NAKATA, Kaoru Motonami, Atsushi Narazaki, Ayumu Onoyama, Shigeto Honda, Ryoichi Fujii, Tomoya Hirata
  • Publication number: 20100308401
    Abstract: A semiconductor layer has a first layer of first conductive type, a second layer of second conductive type, and a third layer. The third layer has a first region of first conductive type, and a second region of second conductive type. A second electrode is in contact with each of the first and second regions. A trench is formed on the semiconductor layer at a surface opposite to its surface facing a first electrode. A gate electrode is embedded in the trench with a gate insulating film interposed therebetween. The gate electrode includes a first portion projecting into the first layer through the first region and the second layer, a second portion projecting into the first layer through the second region and the second layer. The second portion projects into the first layer deeper than a depth in which the first portion projects into the first layer.
    Type: Application
    Filed: March 16, 2010
    Publication date: December 9, 2010
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventor: Atsushi NARAZAKI
  • Publication number: 20100289110
    Abstract: A semiconductor device using one or more guard rings includes a p-type guard ring region surrounding a pn junction region, an insulating film covering the p-type guard ring region, one or more conductive films electrically connected with the p-type guard ring region through one or more contact holes made in the insulating film, and a semi-insulating film covering the insulating film and the conductive films. Thus, a desired breakdown voltage characteristic can be ensured even if a foreign matter or the like adheres to a surface of the conductive films.
    Type: Application
    Filed: December 31, 2009
    Publication date: November 18, 2010
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Yoichiro TARUI, Atsushi Narazaki, Ryoichi Fujii
  • Publication number: 20100240183
    Abstract: A mask layer having a plurality of openings is formed on the first layer. A second layer having a second conductivity type different from the first conductivity type is formed on the first layer by introducing impurities using the mask layer. A third layer having the first conductivity type is formed on the second layer by introducing impurities using the mask layer. A trench extending through the second layer and the third layer to the first layer is formed by carrying out etching using an etching mask including at least the mask layer. A gate insulation film covering a sidewall of the trench is formed. A trench gate filling the trench is formed on the gate insulation film.
    Type: Application
    Filed: September 14, 2009
    Publication date: September 23, 2010
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventor: Atsushi NARAZAKI
  • Patent number: 7741655
    Abstract: A semiconductor device includes a semiconductor substrate having a main surface and a semiconductor element having an insulated gate field effect portion formed in the semiconductor substrate. The semiconductor element includes an n? region, an n-type source region, a p-type base region, an n+ region, and a gate electrode. The n? region and the n-type source region are formed in the main surface. The p-type base region is formed in the main surface adjacent to the n-type source region. The n+ region is formed in the main surface adjacent to the p-type base region and opposed to the n-type source region with the p-type base region being interposed, and has an impurity concentration higher than the n? region. The n? region is formed in the main surface adjacent to the p-type base region and to the n+ region.
    Type: Grant
    Filed: January 28, 2008
    Date of Patent: June 22, 2010
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kenji Hatori, Atsushi Narazaki
  • Publication number: 20090072268
    Abstract: A semiconductor device includes a semiconductor substrate having a main surface and a semiconductor element having an insulated gate field effect portion formed in the semiconductor substrate. The semiconductor element includes an n? region, an n-type source region, a p-type base region, an n+ region, and a gate electrode. The n? region and the n-type source region are formed in the main surface. The p-type base region is formed in the main surface adjacent to the n-type source region. The n+ region is formed in the main surface adjacent to the p-type base region and opposed to the n-type source region with the p-type base region being interposed, and has an impurity concentration higher than the n? region. The n? region is formed in the main surface adjacent to the p-type base region and to the n+ region.
    Type: Application
    Filed: January 28, 2008
    Publication date: March 19, 2009
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Kenji Hatori, Atsushi Narazaki
  • Publication number: 20090014753
    Abstract: A power semiconductor device of the present invention has an active region and an electric field reduction region and includes: an emitter region of a first conductivity type; a base region of a second conductivity type in contact with the emitter region; an electrical strength providing region of the first conductivity type in contact with the base region; a collector region of the second conductivity type in contact with the electrical strength providing region; and a collector electrode in contact with the collector region; wherein the collector region is disposed on both a active region and a electric field reduction region each containing a dopant of the second conductivity type, and the collector region disposed on the electric field reduction region includes a region having a lower density of carriers of the second conductivity type than the collector region disposed on the active region.
    Type: Application
    Filed: November 9, 2007
    Publication date: January 15, 2009
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Yoshiaki Hisamoto, Atsushi Narazaki, Hitoshi Uemura
  • Patent number: 7319264
    Abstract: A semiconductor device has a structure capable of connecting a lead terminal directly to an electrode on a front surface thereof. The semiconductor device includes a first main electrode provided on the front surface, a second main electrode provided on a back surface, and a metal film provided so as to cover at least a portion of a surface of the first main electrode and for soldering the lead terminal thereto. Here, the metal film includes a plurality of opening portions through which the surface of the first main electrode is exposed.
    Type: Grant
    Filed: March 9, 2006
    Date of Patent: January 15, 2008
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Atsushi Narazaki
  • Publication number: 20070114577
    Abstract: One of the aspects of the present invention is to provide a semiconductor device, which includes a semiconductor substrate, a surface electrode on the semiconductor substrate, and a gate wiring on the semiconductor substrate, the gate wiring being spaced from the surface electrode. It also includes a metal layer on the surface electrode, a lead terminal plate connected onto the metal layer, and a polyimide layer covering the gate wiring.
    Type: Application
    Filed: June 29, 2006
    Publication date: May 24, 2007
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventor: Atsushi NARAZAKI
  • Publication number: 20070001265
    Abstract: A semiconductor device has a structure capable of connecting a lead terminal directly to an electrode on a front surface thereof. The semiconductor device includes a first main electrode provided on the front surface, a second main electrode provided on a back surface, and a metal film provided so as to cover at least a portion of a surface of the first main electrode and for soldering the lead terminal thereto. Here, the metal film includes a plurality of opening portions through which the surface of the first main electrode is exposed.
    Type: Application
    Filed: March 9, 2006
    Publication date: January 4, 2007
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventor: Atsushi Narazaki
  • Patent number: 7045831
    Abstract: A semiconductor device of the present invention comprises a semiconductor chip, metal layers formed on a first main surface of the semiconductor chip, a first conductive layer layered on a second main surface of the semiconductor chip, consisting of a plurality of conductive films, a second conductive layer layered on the metal layer, having a layered structure consisting of a plurality of conductive films formed in the same order as in the first conductive layer as viewed from the semiconductor chip and a third conductive layer layered on the metal layer, having a layered structure consisting of a plurality of conductive films formed in the same order as in the first conductive layer as viewed from the semiconductor chip. The plurality of conductive films comprise a nickel film and a low contact resistance conductive film having contact resistance with the semiconductor chip which is lower than that of the nickel film.
    Type: Grant
    Filed: August 16, 2004
    Date of Patent: May 16, 2006
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Atsushi Narazaki
  • Patent number: 6933576
    Abstract: A semiconductor device includes a silicon oxide film (2) formed in a predetermined region on a single crystalline silicon substrate (1) and a gate dielectric film (3) as a thermal oxide film formed by performing thermal oxidation on the surface of the substrate (1) in a region adjacent to the silicon oxide film (2). A polycrystalline silicon (5) (or amorphous silicon) having an oxidized surface is formed on the border between the silicon oxide film (2) and gate dielectric film (3).
    Type: Grant
    Filed: October 9, 2003
    Date of Patent: August 23, 2005
    Assignee: Renesas Technology Corporation
    Inventors: Katsumi Uryuu, Atsushi Narazaki
  • Patent number: 6927455
    Abstract: A first insulator (710) having an opening within a central region (551) is formed on a main surface (61S) of an epitaxial layer (610). Then, p-type impurities are ion implanted through the opening of the first insulator (710) and then heat treatment is carried out, thereby to form a p base layer (621) in the main surface (61S). An insulating film is formed to fill in the opening and then etched back, thereby to form a second insulator (720) on a side surface (71W) of the first insulator (710). Under conditions where the second insulator (720) is present, n-type impurities are ion implanted through the opening and then heat treatment is carried out, thereby to form an n+ source layer (630) in the main surface (61S) of the p base layer (621).
    Type: Grant
    Filed: May 14, 2003
    Date of Patent: August 9, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Atsushi Narazaki