Patents by Inventor Takeo Kagami

Takeo Kagami 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: 20080024934
    Abstract: An MR element incorporates a layered structure. The layered structure includes: a spacer layer having a first surface and a second surface that face toward opposite directions; a free layer disposed adjacent to the first surface of the spacer layer and having a direction of magnetization that changes in response to a signal magnetic field; and a pinned layer disposed adjacent to the second surface of the spacer layer and having a fixed direction of magnetization. The spacer layer is a layer at least part of which is made of a material other than a conductor, and the spacer layer intercepts the passage of currents or limits the passage of currents as compared with a layer entirely made of a conductor. The MR element further incorporates a conductive film that is disposed on the peripheral surface of the layered structure and allows conduction between the free layer and the pinned layer.
    Type: Application
    Filed: April 25, 2007
    Publication date: January 31, 2008
    Applicant: TDK CORPORATION
    Inventors: Takumi Uesugi, Tetsuro Sasaki, Takeo Kagami, Kei Hirata
  • Patent number: 7313857
    Abstract: A method of manufacturing a magneto-resistive device is provided for reducing a degradation in device characteristics due to annealing. The method includes the steps of depositing constituent layers, which make up a magneto-resistive layer on a base, patterning one or more layers of the constituent layers, forming an insulating layer in a region in which the one or more layers of the constituent layers have been removed by the patterning. For forming the insulating layer, the insulating layer is deposited while irradiating an ion beam of a gas mainly containing a rare gas toward the base after the step of patterning.
    Type: Grant
    Filed: June 8, 2004
    Date of Patent: January 1, 2008
    Assignee: TDK Corporation
    Inventors: Takayasu Kanaya, Takeo Kagami
  • Patent number: 7312961
    Abstract: A magnetic head has less variations in the resistance of a magneto-resistive device before and after the magnetic head is left in a high temperature environment so as to have higher stability of the characteristics of the magnetic head against a high temperature environment. A TMR device includes a tunnel barrier layer made of an oxide layer. A DLC film serving as a protection film and an underlying layer therefor are formed on an end face of the TMR device on an air bearing surface side. A layer made of an oxide of a metal or an oxide of a semiconductor is formed between the underlying layer and the end face of the tunnel barrier layer on the air bearing surface side to be in contact with the end face of the tunnel barrier layer.
    Type: Grant
    Filed: September 21, 2004
    Date of Patent: December 25, 2007
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Tetsuya Kuwashima, Kentaro Nagai
  • Publication number: 20070289122
    Abstract: A manufacturing method of an MR element in which current flows in a direction perpendicular to layer planes, includes a step of forming on a lower electrode layer an MR multi-layered structure with side surfaces substantially perpendicular to the layer lamination plane, a step of forming a first insulation layer on at least the side surfaces of the formed MR multi-layered structure, a step of forming a second insulation layer and a magnetic domain control bias layer on the lower electrode layer, and a step of forming an upper electrode layer on the MR multi-layered structure and the magnetic domain control bias layer.
    Type: Application
    Filed: May 31, 2007
    Publication date: December 20, 2007
    Applicant: TDK Corporation
    Inventors: Takeo Kagami, Takayasu Kanaya
  • Patent number: 7308751
    Abstract: A magnetic head has less variations in the resistance of a magneto-resistive device before and after the magnetic head is left in a high temperature environment so as to have higher stability of the characteristics of the magnetic head against a high temperature environment. A TMR device includes a tunnel barrier layer made of an oxide layer. A DLC film serving as a protection film and an underlying layer therefor are formed on an end face of the TMR device on an air bearing surface side. A layer made of an oxide of a metal or an oxide of a semiconductor is formed between the underlying layer and the end face of the tunnel barrier layer on the air bearing surface side to be in contact with the end face of the tunnel barrier layer.
    Type: Grant
    Filed: February 27, 2007
    Date of Patent: December 18, 2007
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Tetsuya Kuwashima, Kentaro Nagai
  • Publication number: 20070279801
    Abstract: A manufacturing method of an MR element in which current flows in a direction perpendicular to layer planes, includes a step of forming on a lower electrode layer an MR multi-layered film having a cap layer at a top thereof, a step of forming a mask on the cap layer of the MR multi-layered film, a step of patterning the MR multi-layered film by milling through the mask to form an MR multi-layered structure, a step of forming a magnetic domain control bias layer by using a lift off method using the mask, a step of, after forming the magnetic domain control bias layer, forming an additional cap layer on the cap layer and a part of the magnetic domain control bias layer, a step of planarizing a top surface of the additional cap layer and the magnetic domain control bias layer, and a step of forming an upper electrode layer on the planarized top surface.
    Type: Application
    Filed: May 30, 2007
    Publication date: December 6, 2007
    Applicant: TDK Corporation
    Inventors: Naoki Ohta, Takeo Kagami
  • Publication number: 20070215573
    Abstract: A resist pattern for lift-off is formed on a first film composed of one or more layers deposited on a substrate. The first film is patterned by dry-etching using the resist pattern as a mask. Subsequently, a second film is deposited with presence of the resist pattern on the first film. Then, the resist pattern for lift-off is removed for conducting lift-off. Subsequently, the resulting substrate is etched. In the etching, the substrate is dry-etched using etching particles which are oriented at an incident angle set in a range of 60° to 90° relative to the normal direction of the substrate.
    Type: Application
    Filed: May 11, 2007
    Publication date: September 20, 2007
    Applicant: TDK Corporation
    Inventors: Takeo Kagami, Kazuki Sato
  • Publication number: 20070206334
    Abstract: A method is provided for manufacturing a magneto-resistive device. The magneto-resistive device is for reducing the deterioration in the characteristics of the device due to annealing. The magneto-resistive device has a magneto-resistive layer formed on one surface side of a base, and an insulating layer formed of two layers and deposited around the magneto-resistive layer. The layer of the insulating layer closest to the base is made of a metal or semiconductor oxide. This layer extends over end faces of a plurality of layers made of different materials from one another, which make up the magneto-resistive device, and is in contact with the end faces of the plurality of layers with the same materials.
    Type: Application
    Filed: May 4, 2007
    Publication date: September 6, 2007
    Applicant: TDK Corporation
    Inventors: Takeo Kagami, Tetsuya Kuwashima, Norio Takahashi
  • Patent number: 7253994
    Abstract: A magnetic head has a base, and a magneto-resistive device supported by the base. The magneto-resistive device includes a magneto-resistive layer formed on one surface side of the base, and a first film. The first film is formed to be in contact with an effective region effectively involved in detection of magnetism in the magneto-resistive layer on both sides or one side of the effective region in a track width direction without overlapping with the effective region. The track width direction is substantially parallel to a film surface of the magneto-resistive layer. The first film is a single-layer film or a multiple-layer film. The first film includes a soft magnetic layer which does not form part of a layer for applying a biasing magnetic field to the free layer. The soft magnetic layer contributes to a reduction in side reading.
    Type: Grant
    Filed: December 29, 2003
    Date of Patent: August 7, 2007
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Tetsuya Kuwashima
  • Publication number: 20070163103
    Abstract: A magnetic head has less variations in the resistance of a magneto-resistive device before and after the magnetic head is left in a high temperature environment so as to have higher stability of the characteristics of the magnetic head against a high temperature environment. A TMR device includes a tunnel barrier layer made of an oxide layer. A DLC film serving as a protection film and an underlying layer therefor are formed on an end face of the TMR device on an air bearing surface side. A layer made of an oxide of a metal or an oxide of a semiconductor is formed between the underlying layer and the end face of the tunnel barrier layer on the air bearing surface side to be in contact with the end face of the tunnel barrier layer.
    Type: Application
    Filed: February 27, 2007
    Publication date: July 19, 2007
    Applicant: TDK Corporation
    Inventors: Takeo Kagami, Tetsuya Kuwashima, Kentaro Nagai
  • Patent number: 7241514
    Abstract: A magneto-resistive device is provided for contributing to a higher MR ratio and a reduced cleaning time for cleaning the surface of a cap layer. In the magneto-resistive device, a cap layer which serves as a protection layer is formed on a free layer which is the topmost layer of a magneto-resistive layer constituting a TMR devise. An upper electrode which is additionally used as an upper magnetic shield is electrically connected to the free layer through an upper metal layer. The cap layer comprised of a two-layer film made up of a conductive layer closer to the free layer and a topmost conductive layer. The conductive layer closer to the free layer is made of a material having higher oxygen bond energy than Ru, such as Zr, Hf, or the like. The topmost conductive layer is made of a material having lower oxygen bond energy, such as a noble metal or the like.
    Type: Grant
    Filed: July 1, 2004
    Date of Patent: July 10, 2007
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Takumi Uesugi, Satoshi Miura, Norio Takahashi
  • Patent number: 7231705
    Abstract: A pattern forming method includes forming a resist pattern for lift off of a first film disposed on a surface side of a base, patterning the first film by dry etching using the resist pattern as a mask, depositing a second film after patterning, removing the resist pattern to remove a portion of the second film on the resist pattern, and etching the surface side of the base after removing the resist pattern. The etching includes dry-etching the surface side of the base using etching particles with a main incident angle of the etching particles to the surface side of the base being set in a range of 60° to 90° relative to a normal direction of the one surface of the base. The dry etching is performed while rotating the base about an axis substantially parallel with the normal direction.
    Type: Grant
    Filed: February 9, 2004
    Date of Patent: June 19, 2007
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Kazuki Sato
  • Patent number: 7207100
    Abstract: A method of manufacturing a magnetic head manufactures a magnetic head having a base, and a laminate stacked on the base and including a magneto-resistive device. The method mechanically polishes a surface of a structure including the base and the laminate close to a magnetic recording medium, wherein the surface of the structure includes an end face of the laminate including an end face of the magneto-resistive device and a surface of the base. Next, the method selectively etches a first region on the surface of the structure close to the magnetic recording medium, wherein the first region includes the surface of the base but does not include the end face of the magneto-resistive device. Subsequently, the method entirely etches the surface of the structure close to the magnetic recording medium.
    Type: Grant
    Filed: December 17, 2004
    Date of Patent: April 24, 2007
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Kunihiro Ueda, Kentaro Nagai, Shunji Saruki
  • Patent number: 7190559
    Abstract: In the thin-film magnetic head of the present invention, the length of each of a pinned layer and an antiferromagnetic layer in their contact area in the depth direction from a surface facing a medium is longer than the length of a free layer in the same direction. When the length of the pinned layer in the depth direction is set longer as such, the direction of magnetization of the pinned layer can be restrained from being tilted by disturbances. Also, the pinned layer and the antiferromagnetic layer have the same length in their contact area in the MR height direction, so that the pinned layer is in contact with the antiferromagnetic layer throughout its length in the MR height direction, thus raising the exchange coupling force, whereby the inclination in the direction of magnetization can be suppressed more effectively.
    Type: Grant
    Filed: September 2, 2003
    Date of Patent: March 13, 2007
    Assignee: TDK Corporation
    Inventors: Takeo Kagami, Noriaki Kasahara
  • Publication number: 20070053114
    Abstract: A magneto-resistive element has a lower layer, a tunnel barrier layer, and an upper layer. The lower layer, the tunnel barrier layer, and the upper layer are disposed adjacent to each other and are stacked in this order. A magnetization direction of either of the lower layer and the upper layer is fixed relative to an external magnetic field, and a magnetization direction of the other layer is variable in accordance with the external magnetic field. A crystalline portion and a non-crystalline portion co-exist in a plane that is parallel with a surface of the tunnel barrier layer.
    Type: Application
    Filed: August 8, 2006
    Publication date: March 8, 2007
    Applicant: TDK CORPORATION
    Inventors: Takumi Uesugi, Satoshi Miura, Takeo Kagami
  • Publication number: 20070035886
    Abstract: A tunneling magneto-resistive element includes: a tunneling magneto-resistive film including an antiferromagnetic layer, a pinned layer, a barrier layer and a free layer; and a lower magnetic shielding film disposed below the tunneling magneto-resistive film with respect to a lamination direction. The barrier layer is constituted of magnesium oxide. The lower magnetic shielding film has a multi-layer structure including a crystalline layer and an amorphous layer disposed above the crystalline layer with respect to the lamination direction. The crystalline layer contains at least one crystal grain having a grain size of 500 nm or more.
    Type: Application
    Filed: August 8, 2006
    Publication date: February 15, 2007
    Applicant: TDK CORPORATION
    Inventors: Takeo Kagami, Naoki Ohta, Kazuki Sato, Satoshi Miura
  • Publication number: 20070008658
    Abstract: The method of making a thin-film magnetic head in accordance with the present invention forms a cover layer on an insulating layer about a magnetoresistive film so as to eliminate a protrusion riding on the magnetoresistive film. Then, the protrusion can be eliminated by etching. The part of insulating layer clad with the cover layer is not etched. This can prevent short-circuit from occurring because of thinning the insulating layer.
    Type: Application
    Filed: September 15, 2006
    Publication date: January 11, 2007
    Applicant: TDK Corporation
    Inventors: Kazuki Sato, Takeo Kagami
  • Publication number: 20060256481
    Abstract: A composite thin-film magnetic head includes a substrate, an under layer formed on the substrate, an MR read head element formed on the under layer and provided with a lower shield layer, an upper shield layer and an MR layer in which a sense current flows in a direction perpendicular to a surface of the MR layer through the upper shield layer and the lower shield layer, an inter-shield insulation layer laminated on the MR read head element, an inductive write head element formed on the inter-shield insulation layer and provided with a first magnetic pole layer, a nonmagnetic layer, a second magnetic pole layer whose end portion is opposed to an end portion of the first magnetic pole layer through the nonmagnetic layer, and a write coil, and an additional shield layer formed between the upper shield layer and the first magnetic pole layer.
    Type: Application
    Filed: March 31, 2006
    Publication date: November 16, 2006
    Applicant: TDK CORPORATION
    Inventors: Takeo Kagami, Hiroshi Kiyono, Hiraku Hirabayashi, Eiichi Omata, Seiji Yari, Takamitsu Sakamoto
  • Patent number: 7134183
    Abstract: The method of making a thin-film magnetic head in accordance with the present invention forms a cover layer on an insulating layer about a magnetoresistive film so as to eliminate a protrusion riding on the magnetoresistive film. Then, the protrusion can be eliminated by etching. The part of insulating layer clad with the cover layer is not etched. This can prevent short-circuit from occurring because of thinning the insulating layer.
    Type: Grant
    Filed: November 10, 2003
    Date of Patent: November 14, 2006
    Assignee: TDK Corporation
    Inventors: Kazuki Sato, Takeo Kagami
  • Publication number: 20060216837
    Abstract: A method for testing a TMR element includes a step of measuring a plurality of resistances of the TMR element by applying a plurality of voltages with different voltage values each other to the TMR element, respectively, a step of calculating a ratio of change in resistance from the measured plurality of resistances of the TMR element, and a step of evaluating the TMR element using the calculated ratio of change in resistance.
    Type: Application
    Filed: March 13, 2006
    Publication date: September 28, 2006
    Applicant: TDK CORPORATION
    Inventors: Nozomu HACHISUKA, Hiroshi Kiyono, Takeo Kagami, Kenji Inage, Norio Takahashi