Patents Assigned to Dowa Electronics Materials Co., Ltd.
  • Patent number: 9012935
    Abstract: A method for manufacturing vertically structured Group III nitride semiconductor LED chips includes a step of forming a light emitting laminate on a growth substrate; a step of forming a plurality of separate light emitting structures by partially removing the light emitting laminate to partially expose the growth substrate; a step of forming a conductive support on the plurality of light emitting structures; a step of lifting off the growth substrate from the plurality of light emitting structures; and a step of cutting the conductive support thereby singulating a plurality of LED chips each having the light emitting structure. The step of partially removing the light emitting laminate is performed such that each of the plurality of light emitting structures has a top view shape of a circle or a 4n-gon (“n” is a positive integer) having rounded corners.
    Type: Grant
    Filed: September 4, 2013
    Date of Patent: April 21, 2015
    Assignees: Wavesquare Inc., Dowa Electronics Materials Co., Ltd.
    Inventors: Meoung Whan Cho, Seog Woo Lee, Pil Guk Jang, Ryuichi Toba, Tatsunori Toyota, Yoshitaka Kadowaki
  • Publication number: 20150102964
    Abstract: A silver particle dispersing solution, which contains 50-70% by weight of silver particles having an average particle diameter of 20 nm or less, is applied on a substrate by the flexographic printing, and then, calcined to produce a booster antenna wherein a silver conductive film, which contains 10-50% by volume of a sintered body of the silver particles and which has a volume resistivity of 3-100 ??·cm, a surface resistivity of 0.5?/? or less and a thickness of 1-6 ?m, is formed on the substrate. Thus, there is provided a booster antenna which has excellent electrical characteristics and flexibility and which can be inexpensively mass-produced.
    Type: Application
    Filed: February 1, 2013
    Publication date: April 16, 2015
    Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Daisuke Itoh, Hidefumi Fujita, Yu Murano, Shinichi Konno
  • Patent number: 9006131
    Abstract: A composite oxide for an exhaust gas purification catalyst is provided which can burn PM in diesel engine exhaust gas at low temperatures and has a good S desorption property. The composite oxide for an exhaust gas purification catalyst is composed of Ce, Bi, Pr, R, and oxygen in a molar ratio of Ce:Bi:Pr:R=(1?x?y?z):x:y:z. The ratios of Ce, Bi, Pr, and R satisfy 0<x+y+z?0.5 and preferably 0<x?0.1, 0<y?0.25, and 0<z?0.3. Particularly, when R is Zr, the composite oxide exhibits a good S desorption property at a temperature of about 600° C. and can recover its catalytic activity at low temperatures. Therefore, the exhaust gas purification catalyst is suitable as a PM combustion catalyst.
    Type: Grant
    Filed: September 28, 2009
    Date of Patent: April 14, 2015
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Yoshiyuki Michiaki, Yoshichika Horikawa
  • Patent number: 9006865
    Abstract: In heteroepitaxially growing a group-III nitride semiconductor on a Si single crystal substrate, the occurrence of cracks initiating in the wafer edge portion can be suppressed. Region A is an outermost peripheral portion outside the principal surface, being a bevel portion tapered. Regions B and C are on the same plane (the principal surface), region B (mirror-surface portion) being the center portion of the principal surface, and region C a region in the principal surface edge portion surrounding region B. The principal surface has a plane orientation, and in region B, is mirror-surface-finished. Region B occupies most of the principal surface of this Si single crystal substrate, and a semiconductor device is manufactured therein. Region C (surface-roughened portion) has a plane orientation as with region B, however, region B is mirror-surface-finished, whereas region C is surface-roughened.
    Type: Grant
    Filed: June 24, 2011
    Date of Patent: April 14, 2015
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Tetsuya Ikuta, Daisuke Hino, Tomohiko Shibata
  • Patent number: 8986446
    Abstract: This invention provides an Si doped GaAs single crystal ingot, which has a low crystallinity value as measured in terms of etch pit density (EPD) per unit area and has good crystallinity, and a process for producing the same. An Si-doped GaAs single crystal wafer produced in a latter half part in the growth of the Si doped GaAs single crystal ingot is also provided. A GaAs compound material is synthesized in a separate synthesizing oven (a crucible). An Si dopant is inserted into the compound material to prepare a GaAs compound material with the Si dopant included therein. The position of insertion of the Si dopant is one where, when the GaAs compound material is melted, the temperature is below the average temperature. After a seed crystal is inserted into a crucible for an apparatus for single crystal growth, the GaAs compound material with the Si dopant included therein and a liquid sealing compound are introduced into the crucible.
    Type: Grant
    Filed: October 25, 2010
    Date of Patent: March 24, 2015
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventor: Yoshikazu Oshika
  • Patent number: 8968824
    Abstract: A silver conductive film is formed on a substrate in a continuous roll-to-roll system by applying a fine silver particle dispersing solution, which contains 30 to 70 wt % of fine silver particles dispersed in a water based dispersing medium, to a halide, such as a chlorine compound, which is applied to the substrate, by flexographic printing, and thereafter, heating the substrate at 60 to 200° C. for 0.1 to 5 seconds in an infrared (IR) heating open, which is installed on the printing path, to carry out calcination.
    Type: Grant
    Filed: March 14, 2013
    Date of Patent: March 3, 2015
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Michael A. Mastropietro, Kimitaka Sato, Hidefumi Fujita
  • Patent number: 8962362
    Abstract: A method for manufacturing vertically structured Group III nitride semiconductor LED chips includes a step of forming a light emitting laminate on a growth substrate; a step of forming a plurality of separate light emitting structures by partially removing the light emitting laminate to partially expose the growth substrate; a step of forming a conductive support on the plurality of light emitting structures; a step of lifting off the growth substrate from the plurality of light emitting structures; and a step of cutting the conductive support thereby singulating a plurality of LED chips each having the light emitting structure. The step of partially removing the light emitting laminate is performed such that each of the plurality of light emitting structures has a top view shape of a circle or a 4n-gon (“n” is a positive integer) having rounded corners.
    Type: Grant
    Filed: November 5, 2009
    Date of Patent: February 24, 2015
    Assignees: Wavesquare Inc., Dowa Electronics Materials Co., Ltd.
    Inventors: Meoung Whan Cho, Seog Woo Lee, Pil Guk Jang, Ryuichi Toba, Tatsunori Toyota, Yoshitaka Kadowaki
  • Patent number: 8963290
    Abstract: The purpose of the present invention is to provide a good ohmic contact for an n-type Group-III nitride semiconductor. An n-type GaN layer and a p-type GaN layer are aequentially formed on a lift-off layer (growth step). A p-side electrode is formed on the top face of the p-type GaN layer. A copper block is formed over the entire area of the top face through a cap metal. Then, the lift-off layer is removed by making a chemical treatment (lift-off step). Then, a laminate structure constituted by the n-type GaN layer, with which the surface of the N polar plane has been exposed, and the p-type GaN layer is subjected to anisotropic wet etching (surface etching step). The N-polar surface after the etching has irregularities constituted by {10-1-1} planes. Then, an n-side electrode is formed on the bottom face of the n-type GaN layer (electrode formation step).
    Type: Grant
    Filed: December 28, 2010
    Date of Patent: February 24, 2015
    Assignees: Dowa Electronics Materials Co., Ltd., Wavesquare Inc.
    Inventors: Ryuichi Toba, Yoshitaka Kadowaki, Meoung Whan Cho, Seog Woo Lee, Pil Guk Jang
  • Patent number: 8951635
    Abstract: A bonded magnet is required to have a large energy product, which is the product of magnetization Br and coercive force Hc. However, in a ferrite powder for a bonded magnet, when the particle diameter is reduced to improve the coercive force, the packing properties are impaired, and the Br is lowered. When the particle diameter is increased to improve the magnetization, the coercive force is lowered. Therefore, to increase the energy product, both the Br and Hc must be increased. A ferrite powder that has a large particle size, is composed of smooth crystals, and suffers only a small reduction in coercive force even after pressurization is obtained by mixing a fine ferrite powder having a small particle size with a ferrite powder calcined at a temperature of 1050° C. to 1300° C. in the presence of a chloride at its saturated vapor pressure and then annealing the mixture at 800° C. to 1100° C. A bonded magnet produced using the powder has an energy product of 2.0 MGOe or more.
    Type: Grant
    Filed: April 9, 2010
    Date of Patent: February 10, 2015
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Shinichi Suenaga, Kouji Hirata, Satoru Tsuboi, Keisuke Ayabe, Kazuyosi Horii
  • Patent number: 8946863
    Abstract: An epitaxial substrate for electronic devices, in which current flows in a lateral direction and of which warpage configuration is properly controlled, and a method of producing the same. The epitaxial substrate for electronic devices is produced by forming a bonded substrate by bonding a low-resistance Si single crystal substrate and a high-resistance Si single crystal substrate together; forming a buffer as an insulating layer on a surface of the bonded substrate on the high-resistance Si single crystal substrate side; and producing an epitaxial substrate by epitaxially growing a plurality of III-nitride layers on the buffer to form a main laminate. The resistivity of the low-resistance Si single crystal substrate is 100 ?·cm or less, and the resistivity of the high-resistance Si single crystal substrate is 1000 ?·cm or more.
    Type: Grant
    Filed: August 2, 2010
    Date of Patent: February 3, 2015
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Tetsuya Ikuta, Daisuke Hino, Ryo Sakamoto, Tomohiko Shibata
  • Publication number: 20150028085
    Abstract: The occurrence of uneven drying in the center and end of a surface of a bonding layer during a desolvation process of a pre-drying step is reduced to ensure highly reliable bonding without peeling of a bonding surface even after repeated exposure to heat shock after bonding. The bonding material of the present invention to achieve the object contains silver nanoparticles coated with organic substance having 6 or less carbon atoms and having an average primary particle diameter of 10 to 30 nm as main silver particles, silver nanoparticles coated with an organic substance having 6 or less carbon atoms and having an average primary particle diameter of 100 to 200 nm as secondary silver particles, two kinds of solvents having different boiling points, and a dispersant.
    Type: Application
    Filed: January 20, 2012
    Publication date: January 29, 2015
    Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Keiichi Endoh, Satoru Kurita, Minami Nagaoka
  • Patent number: 8921227
    Abstract: A method of manufacturing, at a reduced cost, a semiconductor device assembly and a semiconductor device, having a conductive support which is not eroded by an etchant for a lift-off layer even when the lift-off layer is made of a material for which no suitable selective etching solution has been found is provided. In the method of manufacturing the semiconductor device assembly, a plating step of forming a conductive support is carried out such that a first metal which is dissolved with an etchant is encapsulated in second metal which are not dissolved with the etchant, and through-holes for supplying etchant are formed in the second metal.
    Type: Grant
    Filed: May 16, 2013
    Date of Patent: December 30, 2014
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventor: Ryuichi Toba
  • Patent number: 8916068
    Abstract: Provided is a silver micropowder coated with a protective material and capable of more drastically reducing the sintering temperature than before. The silver micropowder comprises silver particles processed to adsorb hexylamine (C6H13—NH2) on the surfaces thereof and having a mean particle diameter DTEM of from 3 to 20 nm or an X-ray crystal particle diameter DX of from 1 to 20 nm. The silver micropowder has the property of forming a conductive film having a specific resistivity of not more than 25 ??·cm when it is mixed with an organic medium to prepare a silver coating material and when a coating film formed of it is fired in air at 120° C. Even when fired at 100° C., it may form a conductive film having a specific resistivity of not more than 25 ??·cm.
    Type: Grant
    Filed: December 25, 2008
    Date of Patent: December 23, 2014
    Assignee: Dowa Electronics Materials Co., Ltd.
    Inventors: Kimitaka Sato, Taku Okano, Taro Nakanoya
  • Publication number: 20140356642
    Abstract: A metallic magnetic powder where a primary particle of each metallic magnetic particle is a powder without forming an aggregate, and a method of making the same that includes manufacturing a metallic magnetic powder constituted of metallic magnetic particles, containing a metallic magnetic phase, with Fe, or Fe and Co as main components, rare earth elements or yttrium and one or more non-magnetic components removing the non-magnetic component from the metallic magnetic with a reducing agent, while making a complexing agent exist for forming a complex with the non-magnetic component in water; oxidizing the metallic magnetic particle with the non-magnetic component removed; substituting water adhered to the oxidized metallic magnetic particle with an organic solvent; and coating the surface of the metallic magnetic particle with an organic matter different from the organic solvent, while maintaining a wet condition of the metallic magnetic particle with the organic solvent adhered thereto.
    Type: Application
    Filed: August 15, 2014
    Publication date: December 4, 2014
    Applicants: THE ARIZONA BOARD OF REGENTS ON BEHALF OF THE UNIVERSITY OF ARIZONA, DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Dong Chul PYUN, Heemin YOO, Hirohisa OMOTO, Takayuki YOSHIDA
  • Publication number: 20140339029
    Abstract: Magnetic functional fluid includes dispersion medium; and dispersed particles which are dispersed in the dispersion medium, wherein the dispersed particles includes: first ferromagnetic particles having an average particle diameter of 0.5 ?m to 50 ?m; and second ferromagnetic particles each having a needle-like shape, each having a smaller particle size than the first ferromagnetic particles, and each having a length ratio of a long axis to a short axis of 2 or more.
    Type: Application
    Filed: May 14, 2014
    Publication date: November 20, 2014
    Applicants: DOWA ELECTRONICS MATERIALS CO., LTD., NAGOYA INSTITUTE OF TECHNOLOGY
    Inventors: Yasushi IDO, Koichi HAYASHI, Takayuki YOSHIDA
  • Patent number: 8883388
    Abstract: A carrier core particle for an electrophotographic developer including a core composition expressed by a general formula: (MnxMgyCaz) FeWO4+V (x+y+z+w=3, ?0.003<v) as a main ingredient, wherein 0.05?y?0.35 and 0.005?z?0.024.
    Type: Grant
    Filed: July 26, 2011
    Date of Patent: November 11, 2014
    Assignees: Dowa Electronics Materials Co., Ltd., Dowa IP Creation Co., Ltd.
    Inventors: Takeshi Kawauchi, Yukihiro Matsuda
  • Patent number: 8878189
    Abstract: An object of the present invention is to provide a Group III nitride semiconductor epitaxial substrate, a Group III nitride semiconductor element, and a Group III nitride semiconductor free-standing substrate, which have good crystallinity, with not only AlGaN, GaN, and GaInN the growth temperature of which is 1050° C. or less, but also with AlxGa1-xN having a high Al composition, the growth temperature of which is high; a Group III nitride semiconductor growth substrate used for producing these, and a method for efficiently producing those. The present invention provides a Group III nitride semiconductor growth substrate comprising a crystal growth substrate including a surface portion composed of a Group III nitride semiconductor which contains at least Al, and a scandium nitride film formed on the surface portion are provided.
    Type: Grant
    Filed: March 25, 2010
    Date of Patent: November 4, 2014
    Assignees: Dowa Holdings Co., Ltd., Dowa Electronics Materials Co., Ltd.
    Inventors: Ryuichi Toba, Masahito Miyashita, Tatsunori Toyota, Yoshitaka Kadowaki
  • Publication number: 20140319557
    Abstract: A method for manufacturing a vertically structured Group III nitride semiconductor LED chip includes a first step of forming a light emitting structure laminate; a second step of forming a plurality of separate light emitting structures by partially removing the light emitting structure laminate to partially expose the growth substrate; a third step of forming a conductive support, which conductive support integrally supporting the light emitting structures; a fourth step of separating the growth substrate by removing the lift-off layer; and a fifth step of dividing the conductive support between the light emitting structures thereby singulating a plurality of LED chips each having the light emitting structure. A first through-hole is formed to open in a central region of each of the light emitting structures such that at least the lift-off layer is exposed, and an etchant is supplied from the first through-hole in the fourth step.
    Type: Application
    Filed: May 12, 2011
    Publication date: October 30, 2014
    Applicants: DOWA ELECTRONICS MATERIALS CO., LTD., WAVESQUARE INC.
    Inventors: Meoung Whan Cho, Seog Woo Lee, Pil Guk Jang, Ryuichi Toba, Yoshitaka Kadowaki
  • Patent number: 8865386
    Abstract: A carrier core particle for an electrophotographic developer includes a core composition expressed by a general formula: MnxFe3?xO4+y (0<x?1, 0<y) as a main ingredient, 0.1 wt % or more of Si, and 0.03 wt % or more of at least one metal element selected from the group consisting of Ca, Sr and Mg.
    Type: Grant
    Filed: March 29, 2011
    Date of Patent: October 21, 2014
    Assignees: Dowa Electronics Materials Co., Ltd., Dowa IP Creation Co., Ltd.
    Inventors: Takeshi Kawauchi, Sho Ogawa
  • Patent number: 8858700
    Abstract: In a bonding material using nanoparticles and a bonding method, use in combination with microparticles is proposed. However, there is the problem in which it is not easy to uniformly mix the nanoparticles and the microparticles. The present invention uses a bonding material including metal nanoparticles having an average particle diameter of 100 nm or less and a surface coated with an organic substance having 6 to 8 carbon atoms, and a polar solvent in an amount of 5 to 20% by mass with respect to a powder of the metal nanoparticles, and objects to be bonded with the bonding material interposed therebetween are fired at 200 to 350° C. under pressure. Thus, the metal nanoparticles are melted and returned to a bulk material, and therefore a bonding layer of the bulk material can be formed at a low temperature equal to or lower than a melting point.
    Type: Grant
    Filed: October 23, 2009
    Date of Patent: October 14, 2014
    Assignee: DOWA Electronics Materials Co., Ltd.
    Inventors: Keiichi Endoh, Aiko Nagahara, Yutaka Hisaeda, Toshihiko Ueyama