Patents by Inventor Kuok San Ho

Kuok San Ho 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: 7663846
    Abstract: A magnetoresistive sensor having a lead overlay defined trackwidth and a pinned layer that extends beyond the stripe height defined by the free layer of the sensor. The extended pinned layer has a strong shape induced anisotropy that maintains pinning of the pinned layer moment. The extended portion of the pinned layer has sides beyond the stripe height that are perfectly aligned with the sides of the sensor within the stripe height. This perfect alignment is made possible by a manufacturing method that uses a mask structure for more than one manufacturing phase, eliminating the need for multiple mask alignments. The lead overlay design allows narrow, accurate trackwidth definition.
    Type: Grant
    Filed: December 7, 2005
    Date of Patent: February 16, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B. V.
    Inventors: James Mac Freitag, Kuok San Ho, Mustafa Michael Pinarbasi, Ching Hwa Tsang
  • Patent number: 7652855
    Abstract: A lead overlay design of a magnetic sensor is described with sensor and free layer dimensions such that the free layer is stabilized by the large demagnetization field due to the shape anisotropy. In one embodiment the giant magnetoresistive (GMR) effect under the leads is destroyed by removing the antiferromagnetic (AFM) and pinned layers above the free layer. The overlaid lead pads are deposited on the exposed spacer layer at the sides of the mask that defines the active region. In other embodiment a layer of electrically insulating material is deposited over the sensor to encapsulate it and thereby insulate it from contact with the hardbias structures. Various embodiments with self-aligned leads are also described. In a variation of the encapsulation embodiment, the insulating material is also deposited under the lead pads so the electrical current is channeled through the active region of the sensor and sidewall deposited lead pads.
    Type: Grant
    Filed: November 9, 2006
    Date of Patent: January 26, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: James Mac Freitag, David Eugene Heim, Kuok San Ho, Wipul Pemsiri Jayasekara, Kim Y. Lee, Tsann Lin, Jyh-Shuey Lo, Mustafa Michael Pinarbasi, Ching Hwa Tsang
  • Patent number: 7649711
    Abstract: A double notched magnetic structure for use in a magnetic head for avoiding stray field writing. The structure could be a magnetic shield, magnetic pole of a write head or some other magnetic structure used in a magnetic head of a magnetic recording system, and has notches formed at both the front end (adjacent to the ABS) and at the back end (away from the ABS). The notches at the front end form a forward protruding portions that performs the necessary function of the structure, such as magnetic shielding, and has laterally extending recessed portions (recessed by the front notches) that move the flux focal points of the structure away from the ABS to avoid stray field writing. The back notches form a backward extending portion that affects the geometry of the structure to prevent the focusing of magnetic flux caused by stray magnetic fields having a component perpendicular to the ABS.
    Type: Grant
    Filed: October 29, 2004
    Date of Patent: January 19, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kuok San Ho, Yimin Hsu, Ching Hwa Tsang
  • Patent number: 7639453
    Abstract: A magnetic head structure for use in perpendicular magnetic recording. The magnetic head includes a magnetic write head having a return pole with a magnetic shunt structure extending from the back end opposite the ABS. The magnetic shunt structure prevents magnetic field from the write coil from reaching and affecting the read head. More specifically the shunt structure prevents magnetic field from the portion of the write coil beyond the back gap (as measured from the ABS) from magnetizing a magnetic shield of the read head. The shunt structure is also configured so as to avoid stray field writing. The size and shape of the shunt structure is therefore, limited to avoid attracting stray fields that might cause such stray field writing.
    Type: Grant
    Filed: August 1, 2006
    Date of Patent: December 29, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hardayal Singh Gill, Kuok San Ho, Wen-Chien David Hsiao, Yimin Hsu, Edward Hin Pong Lee, Vladimir Nikitin
  • Patent number: 7616403
    Abstract: Embodiments of the present invention are directed to structures of a recording head having a winged design for reducing corner stray magnetic fields. In one embodiment, the present invention comprises a magnetic recording head comprising a plurality of components. In embodiments of the present invention at least one of the plurality of components comprises a surface exposed to an air bearing surface when in operation with a recording medium. The surface exposed to the air bearing surface comprises notched edges for constraining corner stray magnetic fields associated therewith.
    Type: Grant
    Filed: October 29, 2004
    Date of Patent: November 10, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Kuok San Ho, Yimin Hsu, Masafumi Mochizuki, Ching Hwa Tsang, Roger Wood
  • Patent number: 7612970
    Abstract: A magnetoresistive sensor having a free layer biased by an in stack bias layer that comprises a layer of antiferromagnetic material. The bias layer can be IrMnCr, IrMn or some other antiferromagnetic material. The free layer is a synthetic free layer having first and second magnetic layers antiparallel coupled across an AP coupling layer. The first magnetic layer is disposed adjacent to a spacer or barrier layer and the second magnetic layer is exchange coupled with the IrMnCr bias layer. The bias layer biases the magnetic moments of the free layer in desired directions parallel with the ABS without pinning the magnetic moments of the free layer.
    Type: Grant
    Filed: February 23, 2005
    Date of Patent: November 3, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hardayal Singh Gill, Kuok San Ho
  • Patent number: 7580230
    Abstract: A magnetoresistive sensor having a shape enhanced pinning and a flux guide structure. First and second hard bias layers and lead layers extend from the sides of a sensor stack. The hard bias layers and leads have a stripe height that is smaller than the stripe height of a free layer, resulting in a free layer that extends beyond the back edge of the lead and hard bias layer. This portion of the free layer that extends beyond the back edge of the leads and hard bias layers provides a back flux guide. Similarly, the sensor may have a free layer that extends beyond the front edge of the lead and hard bias layers to provide a front flux guide. The pinned layer extends significantly beyond the back edge of the free layer, providing the pinned layer with a strong shape enhanced magnetic anisotropy.
    Type: Grant
    Filed: October 24, 2006
    Date of Patent: August 25, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: James Mac Freitag, Kuok San Ho, Mustafa Michael Pinarbasi, Ching Hwa Tsang
  • Publication number: 20090165286
    Abstract: A method for manufacturing a magnetoresistive sensor that decreases the stack height of the sensor. The method includes forming a sensor structure having at its top, a Ru layer and a Ta layer over the Ru layer. An annealing process is performed to set the magnetization of the pinned layer of the sensor structure. After the annealing process has been completed and the Ta layer is no longer needed, an ion milling process is performed to remove the Ta layer.
    Type: Application
    Filed: December 28, 2007
    Publication date: July 2, 2009
    Inventors: Kuok San Ho, Ying Hong, Wipul Pemsiri Jayasekara, Daniele Mauri
  • Patent number: 7522391
    Abstract: A magnetoresistive sensor having an in stack bias structure and a pinned layer having shape enhanced anisotropy. The sensor may be a partial mill design wherein the track width of the sensor is defined by the width of the free layer and the pinned layers extend beyond the trackwidth of the sensor. The sensor has an active area defined by the stripe height of the free layer. The pinned layer extends beyond the stripe height defined by the free layer, thus providing the pinned layer with the shape enhanced anisotropy. The pinned layer structure can be pinned by exchange coupling with a layer of antiferromagnetic material (AFM) layer, with pinning robustness being improved by the shape enhanced anisotropy, or can be a self pinned structure which is pinned by a combination of magnetostriction, AP coupling and shape enhanced anisostropy.
    Type: Grant
    Filed: December 14, 2005
    Date of Patent: April 21, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: James Mac Freitag, Kuok San Ho, Mustafa Michael Pinarbasi, Ching Hwa Tsang
  • Patent number: 7500303
    Abstract: A read head for a disk drive and a method of fabricating the read head with overlaid lead pads that contact the top surface of the sensor between the hardbias structures to define the electrically active region of the sensor are described. The invention deposits the GMR and lead layers before milling away the unwanted material. A photoresist mask with a hole defining the active area of the sensor is preferably patterned over a layer of DLC that is formed into a mask. A selected portion of the exposed lead material is then removed using the DLC as a mask defining the active region of the sensor. A photoresist mask pad is patterned to define the full sensor width. The excess sensor and lead material exposed around the mask is milled away. The layers for the hardbias structure are deposited.
    Type: Grant
    Filed: May 19, 2006
    Date of Patent: March 10, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Tsung Yuan Chen, Kuok San Ho, Mustafa Michael Pinarbasi
  • Patent number: 7497008
    Abstract: An embodiment of the invention is a magnetic head with overlaid lead pads that contact the top surface of the sensor between the hardbias structures and do not contact the hardbias structures which are electrically insulated from direct contact with the sensor. The lead pad contact area on the top of the sensor is defined by sidewall deposition of a conductive material to form leads pads on a photoresist prior to formation of the remainder of the leads. The conductive material for the lead pads is deposited at a shallow angle to maximize the sidewall deposition on the photoresist, then ion-milled at a high angle to remove the conductive material from the field while leaving the sidewall material. An insulation layer is deposited on the lead material at a high angle, then milled at a shallow angle to remove insulation from the sidewall.
    Type: Grant
    Filed: August 24, 2005
    Date of Patent: March 3, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Tsung Yuan Chen, Frederick Hayes Dill, James Mac Freitag, Kuok San Ho, Wipul Pemsiri Jayasekara, Kim Y. Lee, Mustafa Michael Pinarbasi, Ching Hwa Tsang, Patrick Rush Webb
  • Patent number: 7469465
    Abstract: One illustrative method of fabricating a read sensor of a magnetic head includes the steps of forming a plurality of read sensor layers on a wafer; etching the read sensor layers to form a read sensor structure with a trench in front of the read sensor structure; forming a highly porous material within the trench; and slicing the wafer and lapping the sliced wafer through the highly porous material until an air bearing surface (ABS) of the magnetic head is reached. Advantageously, the highly porous material in front of the read sensor structure reduces mechanical stress on the read sensor during the lapping process. This reduces the likelihood that the amplitude of the read sensor will be degraded or set in a “flipped” or reversed orientation, as well as reduces the likelihood that electrostatic discharge (ESD) damage to the read sensor will occur.
    Type: Grant
    Filed: June 30, 2004
    Date of Patent: December 30, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Meng Ding, Kuok San Ho, Tsann Lin, Huey-Ming Tzeng
  • Patent number: 7467459
    Abstract: A current in plane giant magnetoresistive (GMR) sensor having a hard bias layer that extends along the back edge (strip height) of the sensor rather than from the sides of the sensor. The hard bias layer preferably extends beyond the track width of the sensor. Electrically conductive leads, which may be a highly conductive material such as Cu, Rh or Au, or may be an electrically conductive magnetic material extend from the sides of the sensor stack. The bias layer is separated from the sensor stack and from the leads by thin layer of electrically conductive material, thereby preventing current shunting through the hard bias layer.
    Type: Grant
    Filed: April 18, 2005
    Date of Patent: December 23, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hardayal Singh Gill, Kuok San Ho
  • Patent number: 7463459
    Abstract: A self pinned magnetoresistive sensor that has a relatively thick compressive material at either side to assist with self pinning. A shield having recessed portions at either side of the sensor area allows room for a thicker compressive layer than would otherwise be possible.
    Type: Grant
    Filed: February 18, 2004
    Date of Patent: December 9, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Meng Ding, Robert E. Fontana, Jr., Kuok San Ho, Neil Leslie Robertson, Ching Hwa Tsang
  • Patent number: 7420787
    Abstract: A magnetoresistive sensor having a pinned layer that extends beyond the stripe height defined by the free layer of the sensor. The extended pinned layer has a strong shape induced anisotropy that maintains pinning of the pinned layer moment. The extended portion of the pinned layer has sides beyond the stripe height that are perfectly aligned with the sides of the sensor within the stripe height. This perfect alignment is made possible by a manufacturing method that uses a mask structure for more than one manufacturing phase, eliminating the need for multiple mask alignments.
    Type: Grant
    Filed: August 15, 2005
    Date of Patent: September 2, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: James Mac Freitag, Kuok San Ho, Mustafa Michael Pinarbasi, Ching Hwa Tsang
  • Patent number: 7414816
    Abstract: A magnetic head (slider) which requires no lapping is described. The head is fabricated with an air bearing surface that is parallel to the wafer surface. The saw cuts used to separate the individual sliders from the rest of the wafer are perpendicular to the air-bearing surface and do not pass through any critical features. The read and write components are formed from thin films disposed parallel to the air bearing surface and can be side-by-side or tandem in relation to the recording track. The stripe height of the read sensor is controlled by the deposition process rather than by lapping. Various embodiments of the read head include contiguous junction biasing, external hard magnet biasing, and in-stack biasing. In one embodiment a permeable field collector is included below the sensor layer structure. An aperture shield surrounding the sensor at the ABS is included in one embodiment.
    Type: Grant
    Filed: May 28, 2004
    Date of Patent: August 19, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Robert E. Fontana, Jr., Kuok San Ho, Ching Hwa Tsang
  • Publication number: 20080144229
    Abstract: An improved magnetic head for a hard disk drive including a lead overlaid read head in which the read width and read gap are reduced. The read width, which corresponds to the distance between the inner ends of the overlaid electrical leads, is reduced by the fabrication of a thin read width insulation member prior to the fabrication of the overlaid electrical leads. The read gap is reduced by fabricating the overlaid electrical leads from a magnetic, electrically conductive material such as NiFe, whereby the overlaid electrical leads also function as a magnetic shield. The read gap, which is the distance between the first and second magnetic shields is thus reduced as compared to the prior art by the thickness of the electrical leads and the thickness of the prior art second insulation layer formed between the electrical leads and the second magnetic shield.
    Type: Application
    Filed: December 14, 2006
    Publication date: June 19, 2008
    Inventors: Kuok San Ho, Edward Hin Pong Lee, David John Seagle, Ching Hwa Tsang
  • Publication number: 20080112090
    Abstract: A lead overlay design of a magnetic sensor is described with sensor and free layer dimensions such that the free layer is stabilized by the large demagnetization field due to the shape anisotropy. In one embodiment the giant magnetoresistive (GMR) effect under the leads is destroyed by removing the antiferromagnetic (AFM) and pinned layers above the free layer. The overlaid lead pads are deposited on the exposed spacer layer at the sides of the mask that defines the active region. In other embodiment a layer of electrically insulating material is deposited over the sensor to encapsulate it and thereby insulate it from contact with the hardbias structures. Various embodiments with self-aligned leads are also described. In a variation of the encapsulation embodiment, the insulating material is also deposited under the lead pads so the electrical current is channeled through the active region of the sensor and sidewall deposited lead pads.
    Type: Application
    Filed: November 9, 2006
    Publication date: May 15, 2008
    Inventors: James Mac Freitag, David Eugene Heim, Kuok San Ho, Wipul Pemsiri Jayasekara, Kim Y. Lee, Tsann Lin, Jyh-Shuey Lo, Mustafa Michael Pinarbasi, Ching Hwa Tsang
  • Patent number: 7369371
    Abstract: A magnetoresistive sensor having a pinned layer that extends beyond the stripe height defined by the free layer of the sensor. The extended pinned layer has a strong shape induced anisotropy that maintains pinning of the pinned layer moment. The extended portion of the pinned layer has sides beyond the stripe height that are perfectly aligned with the sides of the sensor within the stripe height. This perfect alignment is made possible by a manufacturing method that uses a mask structure for more than one manufacturing phase, eliminating the need for multiple mask alignments.
    Type: Grant
    Filed: August 15, 2005
    Date of Patent: May 6, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: James Mac Freitag, Kuok San Ho, Mustafa Michael Pinarbasi, Ching Hwa Tsang
  • Patent number: 7369374
    Abstract: A current in plane giant magnetoresistive (GMR) sensor having a hard bias layer that extends along the back edge (strip height) of the sensor rather than from the sides of the sensor. The hard bias layer preferably extends beyond the track width of the sensor. Electrically conductive leads, which may be a highly conductive material such as Cu, Rh or Au, or may be an electrically conductive magnetic material extend from the sides of the sensor stack. The bias layer is separated from the sensor stack and from the leads by thin layer of electrically conductive material, thereby preventing current shunting through the hard bias layer.
    Type: Grant
    Filed: April 18, 2005
    Date of Patent: May 6, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hardayal Singh Gill, Kuok San Ho