Patents Assigned to Fuji Electric Device Technology Co., Ltd.
  • Publication number: 20120286326
    Abstract: A power semiconductor device that realizes high-speed turnoff and soft switching at the same time has an n-type main semiconductor layer that includes lightly doped n-type semiconductor layers and extremely lightly doped n-type semiconductor layers arranged alternately and repeatedly between a p-type channel layer and an n+-type field stop layer, in a direction parallel to the first major surface of the n-type main semiconductor layer. A substrate used for manufacturing the semiconductor device is fabricated by forming trenches in an n-type main semiconductor layer 1 and performing ion implantation and subsequent heat treatment to form an n+-type field stop layer in the bottom of the trenches. The trenches are then filled with a semiconductor doped more lightly than the n-type main semiconductor layer for forming extremely lightly doped n-type semiconductor layers. The manufacturing method is applicable with variations to various power semiconductor devices such as IGBT's, MOSFET's and PIN diodes.
    Type: Application
    Filed: July 25, 2012
    Publication date: November 15, 2012
    Applicant: Fuji Electric Device Technology Co., Ltd.
    Inventor: Koh YOSHIKAWA
  • Publication number: 20120244697
    Abstract: A semiconductor device that improves the heat cycle resistance and power cycle resistance of a power module. An electrode member in which copper posts are formed in a plurality of perforations cut in a support made of a ceramic material is soldered onto a side of an IGBT where an emitter electrode is formed. By soldering the copper posts onto the electrode, heat generated in the IGBT is transferred to the electrode member and is radiated. In addition, even if a material of which the IGBT is made and copper differ in thermal expansivity, stress on a soldered interface is reduced and distortion is reduced. This suppresses the appearance of a crack. As a result, the heat cycle resistance and power cycle resistance of a power module can be improved.
    Type: Application
    Filed: June 11, 2012
    Publication date: September 27, 2012
    Applicants: Octec, Inc., Kyocera Corporation, Fuji Electric Device Technology Co., Ltd.
    Inventors: Katsuya Okumura, Yoshikazu Takahashi, Kazunori Takenouchi
  • Publication number: 20120193749
    Abstract: In a semiconductor device having a pn-junction diode structure that includes anode diffusion region including edge area, anode electrode on anode diffusion region, and insulator film on edge area of anode diffusion region, the area of anode electrode above anode diffusion region with insulator film interposed between anode electrode and anode diffusion region is narrower than the area of insulator film on edge area of anode diffusion region.
    Type: Application
    Filed: April 16, 2012
    Publication date: August 2, 2012
    Applicant: Fuji Electric Device Technology Co., Ltd.
    Inventors: Ryouichi KAWANO, Tomoyuki Yamazaki, Michio Nemoto, Mituhiro Kakefu
  • Patent number: 8206778
    Abstract: A method of manufacturing a magnetic recording medium includes the steps of forming an intermediate layer that is electrically conductive over a non-magnetic substrate; forming an aluminum-containing layer on the intermediate layer; forming a plurality of micro pits in the aluminum-containing layer; generating an alumina-containing layer by anode oxidation of the aluminum-containing layer and simultaneously forming a plurality of nano holes in the alumina-containing layer originating from the plurality of micro pits respectively to expose the intermediate layer; cleaning and drying the plurality of nano holes using a fluid selected from the group consisting of a sub- and super-critical carbon dioxide fluid; and depositing a magnetic metal selectively through the plurality of nano holes on the intermediate layer to form a plurality of magnetic recording elements that collectively form a magnetic recording layer.
    Type: Grant
    Filed: February 3, 2010
    Date of Patent: June 26, 2012
    Assignee: Fuji Electric Device Technology Co., Ltd.
    Inventor: Kouichi Tsuda
  • Publication number: 20120045663
    Abstract: A method of manufacturing a magnetic recording medium with high recording density and enabling stable flight of a magnetic head, with high manufacturing yields, is provided. The method includes layering a magnetic layer, a protective layer, and a lubricating layer in order on a substrate, and forming a medium for transfer. The method further includes transferring a magnetic pattern to the medium for transfer, and flattening a surface of the lubricating layer of the medium for transfer for which the magnetic pattern transferring is completed. The surface of the lubricating layer is flattened either by wiping the surface of the lubricating layer using a member without a cutting effect, or by heating the surface of the lubricating layer.
    Type: Application
    Filed: May 10, 2011
    Publication date: February 23, 2012
    Applicant: Fuji Electric Device Technology Co., Ltd.
    Inventor: Narumi SATO
  • Publication number: 20120021254
    Abstract: A perpendicular magnetic recording medium is disclosed which is capable of reducing the orientational dispersion and crystal grain size of a magnetic recording layer, simultaneously reducing the thickness of a non-magnetic intermediate layer, hence, reducing noise, and improving S/N ratio and recording density characteristics. The medium includes a non-magnetic substrate, soft magnetic underlayer, seed layer, first non-magnetic intermediate layer, second non-magnetic intermediate layer, granular magnetic recording layer, exchange coupling force control layer, non-granular magnetic recording layer, protective layer, and lubricant layer sequentially formed on the non-magnetic substrate. The first and second non-magnetic intermediate layers are laminated to form a two-layer non-magnetic intermediate layer and the seed layer is made of a material having an fcc structure.
    Type: Application
    Filed: May 12, 2011
    Publication date: January 26, 2012
    Applicant: FUJI ELECTRIC DEVICE TECHNOLOGY CO., LTD.
    Inventor: Yoshiyuki KUBOKI
  • Patent number: 8097901
    Abstract: A semiconductor device having an IGBT includes: a substrate; a drift layer and a base layer on the substrate; trenches penetrating the base layer to divide the base layer into base parts; an emitter region in one base part; a gate element in the trenches; an emitter electrode; and a collector electrode. The one base part provides a channel layer, and another base part provides a float layer having no emitter region. The gate element includes a gate electrode next to the channel layer and a dummy gate electrode next to the float layer. The float layer includes a first float layer adjacent to the channel layer and a second float layer apart from the channel layer. The dummy gate electrode and the first float layer are coupled with a first float wiring on the base layer. The dummy gate electrode is isolated from the second float layer.
    Type: Grant
    Filed: May 25, 2011
    Date of Patent: January 17, 2012
    Assignees: Denso Corporation, Fuji Electric Device Technology Co., Ltd.
    Inventors: Masaki Koyama, Yoshifumi Okabe, Makoto Asai, Takeshi Fujii, Koh Yoshikawa
  • Publication number: 20120009441
    Abstract: A method of manufacturing a perpendicular magnetic recording medium substrate is capable of reducing the waviness of all wavelength components and a recording medium is capable of reducing contact with a magnetic head to improve the flying stability of the magnetic head. The method includes two polishing operations. The first operation includes polishing a substrate having a Ni—P-based alloy underlayer with a first porous material that includes 0.1 wt % to 25 wt % of alumina, titania, silica, and zirconia abrasive while supplying a first slurry liquid including an organic or inorganic acid and a first abrasive to the underlayer of the substrate. The second operation includes polishing a surface of the underlayer polished in the first polishing with a second porous material while supplying a second slurry liquid including an organic or inorganic acid and a second abrasive with a grain diameter smaller than that of the first abrasive.
    Type: Application
    Filed: March 11, 2011
    Publication date: January 12, 2012
    Applicant: Fuji Electric Device Technology Co., Ltd.
    Inventors: Shoji SAKAGUCHI, Masaoki Miyakoshi, Jun Natsume
  • Publication number: 20120008224
    Abstract: A magnetic transfer master substrate includes a non-magnetic base having depressed portions formed on a surface thereof corresponding to an information signal array, a ferromagnetic body formed in the depressed portions and having a top portion thereof protruding above the surface of the non-magnetic base, and a non-magnetic protective film covering the surface of the non-magnetic base, except for the depressed portion thereof, and also covering a side portion of the ferromagnetic body. A section through the ferromagnetic body, taken perpendicularly to the substrate, includes a round corner, a curvature of which has a radius of no less than 1 nm and no more than 10 nm. The apex of the top portion of the ferromagnetic body protrudes above the surface of the non-magnetic base by 2 nm or more, and protrudes above the surface of the non-magnetic protective film by a distance less than the radius of the curvature.
    Type: Application
    Filed: March 10, 2011
    Publication date: January 12, 2012
    Applicant: Fuji Electric Device Technology Co., Ltd.
    Inventor: Shinji UCHIDA
  • Patent number: 8094395
    Abstract: A magnetic transfer method includes a conjoined body formation step of stacking a transfer master storing transfer information on a transfer receiving body. Air between contact surfaces of the transfer master and transfer receiving body is pushed out in the direction of a non-pressurized area by pressurizing the stacked transfer master and transfer receiving body, to form the conjoined body. The method further includes a transfer step of, by bringing a magnetic field generating module close to the conjoined body, and applying a magnetic field, carrying out a magnetic transfer of the transfer information from the transfer master to the transfer receiving body. A surface roughness of smooth portions of the transfer master in which no transfer information is formed, and the surface roughness of the transfer receiving body, is 1 nm or less.
    Type: Grant
    Filed: June 30, 2010
    Date of Patent: January 10, 2012
    Assignee: Fuji Electric Device Technology Co., Ltd.
    Inventor: Narumi Sato
  • Publication number: 20110317300
    Abstract: A magnetic transfer master substrate may have a ferromagnet pattern corresponding to a signal array. The substrate may include a non-magnetic base having depressed portions, formed on a surface thereof, which correspond to the signal array. A ferromagnet may be disposed in the depressed portions and includes a portion protruding above said surface. A section through the portion of the ferromagnet protruding from said surface taken perpendicularly to a surface of the substrate, includes a curved corner, a radius of curvature of which is no less than 2 nm and no more than 10 nm. The ferromagnet protrudes from the surface of the base by a distance no less than 2 nm and no more than 15 nm. A magnetic transfer method may include bringing the master substrate and a magnetic recording medium into contact and applying a magnetic field to record a magnetization pattern.
    Type: Application
    Filed: April 11, 2011
    Publication date: December 29, 2011
    Applicant: Fuji Electric Device Technology Co., Ltd.
    Inventor: Shinji UCHIDA
  • Publication number: 20110286124
    Abstract: In a magnetic recording medium and magnetic recording medium manufacturing method, it is possible to easily separate a conjoined body without carrying out shape processing in a transfer master in order to separate a conjoined body, and without scratching the magnetic recording medium in a separating step. Moreover, it is possible to mass-produce the magnetic recording medium efficiently without increasing the size of a device. As the central portion of a transfer master is caused to bow convexly in an upward direction, in a condition in which a press receiving surface portion of the transfer master is restrained by a pressing surface of a pressing member, the outer periphery of a magnetic recording medium in a conjoined body is easily separated from a transfer receiving medium contact region of the transfer master in such a way that a predetermined gap is formed.
    Type: Application
    Filed: February 9, 2011
    Publication date: November 24, 2011
    Applicant: Fuji Electric Device Technology Co., Ltd.
    Inventor: Narumi SATO
  • Patent number: 8039133
    Abstract: A magnetic recording medium, and method of manufacturing the same, is provided with excellent recording performance by employing a granular magnetic layer having a specified composition. A magnetic recording medium according to the present invention comprises a nonmagnetic underlayer, a granular magnetic layer, a protective film, and a liquid lubrication layer sequentially laminated on a nonmagnetic substrate. The granular magnetic layer consists of ferromagnetic crystal grains containing cobalt and nonmagnetic grain boundary region surrounding the ferromagnetic crystal grains. The ferromagnetic crystal grains contain platinum in the range of 15 at % to 17 at %.
    Type: Grant
    Filed: April 26, 2005
    Date of Patent: October 18, 2011
    Assignee: Fuji Electric Device Technology Co., Ltd.
    Inventors: Miyabi Nakamura, Takahiro Shimizu, Hiroyuki Uwazumi, Naoki Takizawa, Tadaaki Oikawa
  • Publication number: 20110242693
    Abstract: This invention provides a magnetic recording medium evaluation apparatus and evaluation method which yield results having good correlation with error rate measurements even when comparing media with different structures. Signals from a function generator are recorded in a magnetic recording medium. The recording signals are also passed through a first digital filter to obtain ideal restored signals. Reproduced signals from the magnetic recording medium are sampled in synchronization with the output from the function generator, and the discrete signals are passed through a second digital filter to obtain restored signals. The outputs from the first and second digital filters are input to an operational amplifier, and the difference between the restored signals and the ideal restored signals is taken for each sampling of the recording signals. The signal-to-noise ratio of the ideal restored signal to the average of the absolute value of this difference is used to evaluate signal quality.
    Type: Application
    Filed: June 17, 2011
    Publication date: October 6, 2011
    Applicant: Fuji Electric Device Technology Co., Ltd.
    Inventor: Takashi HAYASHI
  • Publication number: 20110244269
    Abstract: A perpendicular magnetic recording medium includes at least a soft-magnetic underlayer, a non-magnetic underlayer, a ferromagnetic intermediate layer, a non-magnetic intermediate layer, and a perpendicular magnetic recording layer sequentially stacked on a non-magnetic substrate. In an embodiment, the ferromagnetic intermediate layer is formed of a CoCr based alloy, a product Bs·t of a saturation magnetic flux density and film thickness of the ferromagnetic intermediate layer is within a range of 0.15 to 3.6 T·nm, and the non-magnetic intermediate layer has a film thickness of 3 nm or more.
    Type: Application
    Filed: March 10, 2011
    Publication date: October 6, 2011
    Applicant: Fuji Electric Device Technology Co., Ltd.
    Inventor: Hisato Kato
  • Publication number: 20110242690
    Abstract: A system and method for magnetic transfer. A magnetic transfer device includes a plurality of pairs of magnetic field generating units that apply a magnetic field to a contact body which includes a master disk in close contact with a magnetic recording medium, wherein the master disk has a pattern of preformatted signals. The magnetic field generating units, falling within a specified length range, are moved in synchrony at a predetermined speed in the directions of the outer periphery while the contact body is caused to rotate by a rotation drive unit. The system and method provide a magnetic transfer method and a magnetic transfer device that, by reducing the area of magnetic field generating units that apply a transfer magnetic field, can reduce an attractive force (or repulsive force) between the magnets, and furthermore, shorten a processing time for the transfer.
    Type: Application
    Filed: February 11, 2011
    Publication date: October 6, 2011
    Applicant: Fuji Electric Device Technology Co., Ltd.
    Inventor: Hiroto KIKUCHI
  • Patent number: 8031562
    Abstract: A master disk for magnetic transfer of a reference servo signal in a spiral mode, having a pattern including a plurality of dots groups, which are disposed at different radial positions of the master disk with a first pitch, and correspond to the reference servo signal in the spiral mode. Each of the plurality of dot groups includes a plurality of dots, successively disposed with a second pitch along a circumferential direction of the master disk at a same one of the radial positions. Each of the plurality of dots is of a ferromagnetic material, and has four sides, two opposing sides thereof extending in the circumferential direction, and the other two opposing sides thereof extending in a radial direction of the master disk.
    Type: Grant
    Filed: October 22, 2010
    Date of Patent: October 4, 2011
    Assignee: Fuji Electric Device Technology Co., Ltd.
    Inventor: Hiroto Kikuchi
  • Publication number: 20110229657
    Abstract: An apparatus and method for forming a carbon protective layer on a substrate using a plasma CVD method allows a more uniform in-plane distribution of the carbon protective layer thickness. The apparatus includes an annular anode that generates a plasma beam and a disk-shaped shield disposed between the anode and the substrate. The anode, the shield, and the substrate are concentrically arranged so that a straight line connecting the centers of the anode and the substrate is perpendicular to the deposition surface of the substrate where the carbon protective layer is to be formed. The center of the shield is also on the straight line.
    Type: Application
    Filed: May 31, 2011
    Publication date: September 22, 2011
    Applicant: FUJI ELECTRIC DEVICE TECHNOLOGY CO., LTD.
    Inventor: Naruhisa NAGATA
  • Patent number: 8023213
    Abstract: A defect inspection method and device for a perpendicular magnetic recording medium that has discrete recording tracks and grooves between recording tracks, including DC demagnetizing the perpendicular magnetic recording medium, detecting a reproduced signal from the perpendicular magnetic recording medium after the DC demagnetizing, removing output fluctuation components caused by the grooves from the reproduced signal using a filter with a prescribed cutoff frequency and separating a peak output of the reproduced signal, comparing the peak output with a prescribed reference signal, and identifying a location where the peak output exceeds the reference signal as a defect location.
    Type: Grant
    Filed: March 24, 2009
    Date of Patent: September 20, 2011
    Assignee: Fuji Electric Device Technology Co., Ltd
    Inventor: Hiroto Kikuchi
  • Publication number: 20110220962
    Abstract: A semiconductor device having an IGBT includes: a substrate; a drift layer and a base layer on the substrate; trenches penetrating the base layer to divide the base layer into base parts; an emitter region in one base part; a gate element in the trenches; an emitter electrode; and a collector electrode. The one base part provides a channel layer, and another base part provides a float layer having no emitter region. The gate element includes a gate electrode next to the channel layer and a dummy gate electrode next to the float layer. The float layer includes a first float layer adjacent to the channel layer and a second float layer apart from the channel layer. The dummy gate electrode and the first float layer are coupled with a first float wiring on the base layer. The dummy gate electrode is isolated from the second float layer.
    Type: Application
    Filed: May 25, 2011
    Publication date: September 15, 2011
    Applicants: DENSO CORPORATION, Fuji Electric Device Technology Co., Ltd.
    Inventors: Masaki Koyama, Yoshifumi Okabe, Makoto Asai, Takeshi Fujii, Koh Yoshikawa