Patents by Inventor Katsuro Watanabe

Katsuro Watanabe 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).

  • Patent number: 8373943
    Abstract: According to one embodiment, a method for producing a magnetic head includes depositing a first film above a substrate, etching a pattern into the first film, depositing a second film on the etched portion of the first film, and depositing a third film above the first and second film to form a multilayer magnetic film, wherein the second film is embedded between the first and third film in a portion of the first film that is removed. In another embodiment, a differential magnetic read head includes a magnetic multilayer film comprising a stack of a first magnetic sensor film and a second magnetic sensor film which are not magnetically connected and a hard magnetic film provided on both sides in a track width direction of the magnetic multilayer film for controlling a magnetic domain of the magnetic multilayer film. The hard magnetic film is a laminated structure as described above.
    Type: Grant
    Filed: November 8, 2010
    Date of Patent: February 12, 2013
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kan Yasui, Nobuo Yoshida, Katsuro Watanabe, Norihiro Okawa
  • Patent number: 8355224
    Abstract: Embodiments of the present invention help to prevent a head characteristic from being deteriorated by re-deposition or damage which occurs when a sensor film is etched, a track width is narrowed, and the head characteristic is stabilized. According to one embodiment, when it is assumed that the thickness of the sensor film on an air bearing surface is T, and a distance between an end of a medium layer that is interposed between a free layer and a pinned layer which comprise the sensor film and an end of the sensor film lowest portion, a relationship of 1.2×T?X?2.5×T is satisfied, and the ends of a pair of magnetic films which are in contact with both sides in the track-width direction through an insulator do not exist in the track central portion from the free layer end.
    Type: Grant
    Filed: January 29, 2008
    Date of Patent: January 15, 2013
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Satoru Okamoto, Koji Okazaki, Shuuichi Kojima, Nobuo Yoshida, Katsuro Watanabe, Hiroyuki Katada
  • Patent number: 8335057
    Abstract: According to one embodiment, a CPP magnetoresistive head includes a magnetoresistive film comprising a free layer above a non-magnetic intermediate layer and a fixed layer below the non-magnetic intermediate layer, wherein the magnetoresistive film is between a lower magnetic shield layer and an upper magnetic shield layer. The CPP magnetoresistive head also includes a domain control film on each side of the magnetoresistive film, wherein a sense current flows through the magnetoresistive film between the upper magnetic shield layer and the lower magnetic shield layer. The CPP magnetoresistive head also includes a high heat conductivity layer, and a heat dissipation layer having a high heat conductivity and a low linear expansion coefficient, the heat dissipation layer being disposed at the back in a device height direction of the magnetoresistive film and on each side of the domain control film.
    Type: Grant
    Filed: August 5, 2009
    Date of Patent: December 18, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Masahiro Osugi, Takayoshi Ohtsu, Shigeo Fujita, Katsuro Watanabe, Koji Kataoka
  • Patent number: 8270123
    Abstract: In one embodiment, a vertical-current-type reproducing magnetic head includes a sensor film, an upper shield paired with a lower shield that together flow a current into the sensor film in a thickness direction of the sensor film, and magnetic-domain control magnetic films provided above both sides of the sensor film in a track width direction of the sensor film. The shield is formed via a nonmagnetic adhesion layer including a discontinuous region near the sensor film, and the sensor film contacts the upper shield. In another embodiment, a method includes forming a resist layer, etching a sensor film while using the resist layer as a mask, forming first insulating films, domain-control magnetic films, and nonmagnetic adhesion layers in a stacked manner, lifting-off the resist layer, and forming an upper shield that together with a lower shield flow current into the sensor film in a thickness direction of the sensor film.
    Type: Grant
    Filed: November 9, 2009
    Date of Patent: September 18, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kenichi Akita, Nobuo Yoshida, Katsuro Watanabe
  • Patent number: 8184406
    Abstract: Embodiments in accordance with the present invention provide a thin film magnetic head for preventing a short-circuit failure during formation of a track portion or a stripe-height portion and improving a yield. In one embodiment, a stripe-height direction is first formed, and then a track-width direction is formed. A third insulating film having a smoothly shaped wall surface is formed on a first insulating film during stripe-height formation. During formation of the third insulating film, an optimized lift-off pattern is used to smooth an edge shape.
    Type: Grant
    Filed: April 10, 2007
    Date of Patent: May 22, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands BV
    Inventors: Nubuo Yoshida, Katsuro Watanabe, Takayoshi Ohtsu
  • Patent number: 8149548
    Abstract: Embodiments of the present invention provide a magnetic head having a read head of stable reading operation and with less magnetic fluctuation noise. According to one embodiment, a free layer has a structure comprising two ferromagnetic layers (a first free layer and a second free layer) that are coupled anti-ferromagnetically by way of a non-magnetic intermediate layer, in which the magnetization amount of the first free layer is set to larger than the magnetization amount of the second free layer. Further, the magnetic domains in the first free layer and the second free layer are stabilized simultaneously by increasing the distance between the second free layer and the magnetic domain control film to be more than the distance between the first free layer and the magnetic domain control film, thereby adjusting the magnetization amount of the magnetic domain control film.
    Type: Grant
    Filed: April 17, 2009
    Date of Patent: April 3, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands BV
    Inventors: Masahiko Hatatani, Katsuro Watanabe, Nubuo Yoshida, Katsumi Hoshino
  • Publication number: 20110222188
    Abstract: The reduction in a recording magnetic field due to the narrowing of recording track width along with the improved surface recording density is prevented and the increasing of accuracy in the track width is achieved, enabling an improvement in recording performance. In a perpendicular magnetic recording head, a main pole 13 includes a first main pole portion 131 having an inverse trapezoidal shape with a bevel angle and a second main pole portion 132 laminated on the first main pole portion. The second main pole portion 132 has no bevel angle, is generally rectangular and defines track width. The second main pole portion has a tapered shape extending from the predetermined position of a flare portion toward an air bearing surface.
    Type: Application
    Filed: February 3, 2011
    Publication date: September 15, 2011
    Inventors: Kimitoshi Etoh, Masayoshi Ishibashi, Katsuro Watanabe, Junichi Hashimoto
  • Publication number: 20110116184
    Abstract: According to one embodiment, a method for producing a magnetic head includes depositing a first film above a substrate, etching a pattern into the first film, depositing a second film on the etched portion of the first film, and depositing a third film above the first and second film to form a multilayer magnetic film, wherein the second film is embedded between the first and third film in a portion of the first film that is removed. In another embodiment, a differential magnetic read head includes a magnetic multilayer film comprising a stack of a first magnetic sensor film and a second magnetic sensor film which are not magnetically connected and a hard magnetic film provided on both sides in a track width direction of the magnetic multilayer film for controlling a magnetic domain of the magnetic multilayer film. The hard magnetic film is a laminated structure as described above.
    Type: Application
    Filed: November 8, 2010
    Publication date: May 19, 2011
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kan Yasui, Nobuo Yoshida, Katsuro Watanabe, Norihiro Okawa
  • Patent number: 7944651
    Abstract: Embodiments of the present invention help to prevent a reduction in the bias magnetic field of a current perpendicular to the plane-type (CPP-type) magnetoresistive effect head, thus suppressing a reduction in read output. According to one embodiment, a CPP-type magnetoresistive effect film is formed on top of a lower magnetic shield. A refill insulation film and a magnetic domain control layer are formed on both sides of an intermediate layer and a free layer of the CPP-type magnetoresistive effect film. A side wall protection film is formed on a side wall of the refill insulation film and on top of the free layer so as to define the height of the magnetic domain control layer. To increase the film thickness of the magnetic domain control layer, the magnetic domain control layer and the refill insulation film are higher than the top surface of the free layer.
    Type: Grant
    Filed: January 4, 2008
    Date of Patent: May 17, 2011
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Masahiro Ousugi, Kouji Okazaki, Satoru Okamoto, Katsuro Watanabe
  • Patent number: 7859799
    Abstract: Embodiments in accordance with the present invention reduce the influence of etching damage at junction edge of a magnetoresistive film in the sensor height direction, lower the deterioration of dielectric breakdown voltage between an upper magnetic shield layer and a lower magnetic shield layer and instability of reproducing property resulting from shield process, and maintain electrostatic capacity to a small value in a CPP magnetoresistive head. In an embodiment of a magnetoresistive head of the present invention, length in the sensor height direction of bottom surface of a pinning layer is longer than the length in the sensor height direction of bottom surface of a first ferromagnetic layer.
    Type: Grant
    Filed: February 13, 2007
    Date of Patent: December 28, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Katsuro Watanabe, Taku Shintani, Kazuhiro Ueda, Masahiro Osugi
  • Patent number: 7735213
    Abstract: Embodiments of the present invention provide a method of fabricating a magnetic head slider realizing high-recording density at high-yields by preventing formation of a short circuit on the air-bearing surface of a magnetic head slider and preventing formation of an oxidized layer with significant film thickness which increases the effective magnetic spacing, on the air-bearing surface of the magnetic head slider. According to one embodiment, after air-bearing surface mechanical lapping of a row bar or a magnetic head slider, cleaning is performed by ion beam bombardment to remove a conductive smear. Oxygen exposure is performed to recover a damaged region which was formed by ion beam bombardment at the end face of an intermediate layer of a magnetoresistive film 5. Thereafter, air-bearing surface protection films are formed and followed by rail formation. If the processes are performed on the row bar, the row bar is cut into individual separated magnetic head sliders.
    Type: Grant
    Filed: August 24, 2007
    Date of Patent: June 15, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Nobuto Yasui, Katsuro Watanabe, Takateru Seki, Kazuhito Miyata, Tetsuya Matsusaki
  • Publication number: 20100142100
    Abstract: According to one embodiment, a CPP structure magnetoresistive head includes a magnetoresistive sensor film between a lower shield layer and an upper shield layer and a longitudinal biasing layer disposed at each side of the magnetoresistive sensor film via a read track width defining insulator film. In the stripe height direction, the length of the longitudinal biasing layer is longer than the length of a second ferromagnetic layer in which its magnetization rotates in response to the external magnetic field. The second ferromagnetic layer is one of the layers comprising the magnetoresistive sensor film. At a stripe height, the surface of each longitudinal biasing layer has a step to change the thickness thereof across the step so that the air bearing surface section thereof has a larger thickness than any other section. Other structures using a magnetoresistive head and methods of production thereof are described as well.
    Type: Application
    Filed: December 4, 2009
    Publication date: June 10, 2010
    Inventors: Nobuo Yoshida, Katsuro Watanabe, Masahiro Ousugi, Atsushi Kato
  • Publication number: 20100123977
    Abstract: In one embodiment, a vertical-current-type reproducing magnetic head includes a sensor film, an upper shield paired with a lower shield that together flow a current into the sensor film in a thickness direction of the sensor film, and magnetic-domain control magnetic films provided above both sides of the sensor film in a track width direction of the sensor film. The shield is formed via a nonmagnetic adhesion layer including a discontinuous region near the sensor film, and the sensor film contacts the upper shield. In another embodiment, a method includes forming a resist layer, etching a sensor film while using the resist layer as a mask, forming first insulating films, domain-control magnetic films, and nonmagnetic adhesion layers in a stacked manner, lifting-off the resist layer, and forming an upper shield that together with a lower shield flow current into the sensor film in a thickness direction of the sensor film.
    Type: Application
    Filed: November 9, 2009
    Publication date: May 20, 2010
    Inventors: Kenichi Akita, Nobuo Yoshida, Katsuro Watanabe
  • Publication number: 20100053821
    Abstract: According to one embodiment, a magnetoresistive head has a magnetoresistive sensor film between a lower shield layer and an upper shield layer. The magnetoresistive sensor film is formed by stacking at least a pinning layer, a first ferromagnetic layer, an intermediate layer, and a second ferromagnetic layer, in which a sense current flows so as to pass through an interface between the intermediate layer and the second ferromagnetic layer, and a resistance change of the magnetoresistive sensor film in accordance with the change of an external magnetic field is detected. Also, a lateral side metal layer having an electric resistivity lower than the electric resistivity of the pinning layer is disposed at least on a side wall of the pinning layer among side walls of layers constituting the magnetoresistive sensor film, the lateral side metal layer being in contact with the lower shield layer. Other embodiments are described as well.
    Type: Application
    Filed: August 25, 2009
    Publication date: March 4, 2010
    Inventors: Katsuro Watanabe, Shigeo Fujita, Norihiro Ookawa, Kenichi Meguro
  • Publication number: 20100046121
    Abstract: According to one embodiment, a CPP magnetoresistive head includes a magnetoresistive film comprising a free layer above a non-magnetic intermediate layer and a fixed layer below the non-magnetic intermediate layer, wherein the magnetoresistive film is between a lower magnetic shield layer and an upper magnetic shield layer. The CPP magnetoresistive head also includes a domain control film on each side of the magnetoresistive film, wherein a sense current flows through the magnetoresistive film between the upper magnetic shield layer and the lower magnetic shield layer. The CPP magnetoresistive head also includes a high heat conductivity layer, and a heat dissipation layer having a high heat conductivity and a low linear expansion coefficient, the heat dissipation layer being disposed at the back in a device height direction of the magnetoresistive film and on each side of the domain control film.
    Type: Application
    Filed: August 5, 2009
    Publication date: February 25, 2010
    Inventors: Masahiro Osugi, Takayoshi Ohtsu, Shigeo Fujita, Katsuro Watanabe, Koji Kataoka
  • Publication number: 20090262465
    Abstract: Embodiments of the present invention provide a magnetic head having a read head of stable reading operation and with less magnetic fluctuation noise. According to one embodiment, a free layer has a structure comprising two ferromagnetic layers (a first free layer and a second free layer) that are coupled anti-ferromagnetically by way of a non-magnetic intermediate layer, in which the magnetization amount of the first free layer is set to larger than the magnetization amount of the second free layer. Further, the magnetic domains in the first free layer and the second free layer are stabilized simultaneously by increasing the distance between the second free layer and the magnetic domain control film to be more than the distance between the first free layer and the magnetic domain control film, thereby adjusting the magnetization amount of the magnetic domain control film.
    Type: Application
    Filed: April 17, 2009
    Publication date: October 22, 2009
    Inventors: Masahiko Hatatani, Katsuro Watanabe, Nubuo Yoshida, Katsumi Hoshino
  • Patent number: 7561384
    Abstract: A high output magneto-resistive sensor is provided by suppressing leftover resist mask after lift-off and generation of a fence, and by making it easy to remove the redepositions deposited on the side wall in the track width direction or on the side wall in the sensor height direction of the magnetoresistive film. As a means to solve a fence and lift-off leftover of a resist in a process for forming a track and a process for forming a sensor height, a stopper layer is provided on the magnetoresistive film and the stopper layer on the refill film, and performing lift-off by CMP. By using a metallic material which has a small CMP polishing rate for at least the first stopper layer, the magnetoresistive film and the first stopper layer can be etched simultaneously and a pattern formed. As a result, decrease of the height of the resist mask by RIE can be suppressed and lift-off leftover can be prevented.
    Type: Grant
    Filed: November 29, 2005
    Date of Patent: July 14, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Masahiro Osugi, Taku Shintani, Katsuro Watanabe, Nobuo Yoshida
  • Patent number: 7505232
    Abstract: In a side shield structure employed to narrow the effective track, a noise caused by the side shield structure can be reduced. In one embodiment, the side shield is inclined with respect to the film plane to suppress the generation of a magnetic pole in the end portion of the side shield. To this end, the side face of a device is inclined at a desired angle. Further, a reproduction device is formed at two or more angles ?1 and ?2 to improve the track width accuracy.
    Type: Grant
    Filed: June 24, 2005
    Date of Patent: March 17, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Chiseki Haginoya, Masahiko Hatatani, Chiaki Ishakawa, Kenichi Meguro, Kazuhiro Nakamoto, Katsuro Watanabe
  • Publication number: 20090046394
    Abstract: Embodiments of the present invention help to prevent a head characteristic from being deteriorated by re-deposition or damage which occurs when a sensor film is etched, a track width is narrowed, and the head characteristic is stabilized. According to one embodiment, when it is assumed that the thickness of the sensor film on an air bearing surface is T, and a distance between an end of a medium layer that is interposed between a free layer and a pinned layer which comprise the sensor film and an end of the sensor film lowest portion, a relationship of 1.2×T?x?2.5×T is satisfied, and the ends of a pair of magnetic films which are in contact with both sides in the track-width direction through an insulator do not exist in the track central portion from the free layer end.
    Type: Application
    Filed: January 29, 2008
    Publication date: February 19, 2009
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Satoru Okamoto, Koji Okazaki, Shuuichi Kojima, Nobuo Yoshida, Katsuro Watanabe, Hiroyuki Katada
  • Patent number: 7446981
    Abstract: This invention provides a high-output magnetic head with a high yield, which is capable of minimizing sense current leak or noise caused by a shift of the magnetic wall of an upper shield layer. In one embodiment, the magnetic head is fabricated so that the height of the upper surface of the refill film along the sensor height direction is the same as that of the magnetoresistance layer in a portion where the refill film along the sensor height direction comes in contact with the magnetoresistance layer and the distance from the upper surface of the refill film along the sensor height direction to the upper surface of the lower shield layer gradually increases in a region from the portion where the refill film along the sensor height direction comes in contact with the magnetoresistance layer to a point at a certain distance away from the portion.
    Type: Grant
    Filed: July 24, 2006
    Date of Patent: November 4, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Taku Shintani, Katsuro Watanabe, Nobuo Yoshida, Hisako Takei