Patents by Inventor Kuok Ho

Kuok 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).

  • Publication number: 20070133133
    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: Application
    Filed: December 14, 2005
    Publication date: June 14, 2007
    Inventors: James Freitag, Kuok Ho, Mustafa Pinarbasi, Ching Tsang
  • Publication number: 20070127167
    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: Application
    Filed: December 7, 2005
    Publication date: June 7, 2007
    Inventors: James Freitag, Kuok Ho, Mustafa Pinarbasi, Ching Tsang
  • Publication number: 20070086122
    Abstract: A current perpendicular to plane (CPP) magnetoresistive sensor having a track width that is defined by an area of contact with a shield/lead. The sensor includes a sensor stack having a width W1. A current path defining insulation layer formed over the sensor stack has an opening with a width W2 that is significantly smaller than the width W1 of the sensor stack. A shield/lead extends into the opening in the insulation layer to contact a surface of the sensor stack. This area of contact between the shield/lead and the surface of the sensor stack defines an active area of the sensor having a width of substantially W2. The edges of the sensor stack, which may have compromised magnetic properties due to the formation of the sensor stack are advantageously removed from the active area of the senor. Furthermore, the edges of the free layer, which may be pinned by the hard bias layers are also advantageously removed from the active area of the sensor.
    Type: Application
    Filed: October 19, 2005
    Publication date: April 19, 2007
    Inventors: James Freitag, Kuok Ho, Mustafa Pinarbasi, Ching Tsang
  • Publication number: 20070035887
    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: Application
    Filed: August 15, 2005
    Publication date: February 15, 2007
    Inventors: James Freitag, Kuok Ho, Mustafa Pinarbasi, Ching Tsang
  • Publication number: 20070035891
    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: Application
    Filed: August 15, 2005
    Publication date: February 15, 2007
    Inventors: James Freitag, Kuok Ho, Mustafa Pinarbasi, Ching Tsang
  • Publication number: 20060232893
    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: Application
    Filed: April 18, 2005
    Publication date: October 19, 2006
    Inventors: Hardayal Gill, Kuok Ho
  • Publication number: 20060230601
    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: Application
    Filed: April 18, 2005
    Publication date: October 19, 2006
    Inventors: Hardayal Gill, Kuok Ho
  • Publication number: 20060196040
    Abstract: A method for making a magnetoresistive read head so that the pinned ferromagnetic layer is wider than the stripe height of the free ferromagnetic layer uses ion milling with the ion beam aligned at an angle to the substrate supporting the stack of layers making up the read head. The stack is patterned with photoresist to define a rectangular region with front and back long edges aligned parallel to the read head track width. After ion milling in two opposite directions orthogonal to the front and back long edges, the pinned layer width has an extension. The extension makes the width of the pinned layer greater than the stripe height of the free layer after the substrate and stack of layers are lapped. The length of the extension is determined by the angle between the substrate and the ion beam and the thickness of the photoresist.
    Type: Application
    Filed: March 3, 2005
    Publication date: September 7, 2006
    Inventors: Marie-Claire Cyrille, Meng Ding, Elizabeth Dobisz, Kuok Ho, Scott MacDonald
  • Publication number: 20060187591
    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: Application
    Filed: February 23, 2005
    Publication date: August 24, 2006
    Inventors: Hardayal Gill, Kuok Ho
  • Publication number: 20060092562
    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: Application
    Filed: October 29, 2004
    Publication date: May 4, 2006
    Inventors: Kuok Ho, Yimin Hsu, Masafumi Mochizuki, Ching Tsang, Roger Wood
  • Publication number: 20060092582
    Abstract: A current perpendicular to plane (CPP) having hard magnetic bias layers located at the back of the sensor, opposite the air bearing surface. The bias layer is magnetostatically coupled with the free layer to bias the free layer in a desired direction parallel with the ABS. First and second magnetic shield layers may be provided at either lateral side of the sensor to provide exceptional track width definition. The placement of the bias layer at the back of the sensor makes possible the addition of magnetic shields at the sides of the sensor.
    Type: Application
    Filed: November 4, 2004
    Publication date: May 4, 2006
    Inventors: Hardayal Gill, Kuok Ho
  • Publication number: 20060092566
    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: Application
    Filed: October 29, 2004
    Publication date: May 4, 2006
    Inventors: Kuok Ho, Yimin Hsu, Ching Tsang
  • Publication number: 20060092565
    Abstract: A magnetic structure for use in a magnetic head for avoiding stray field writing. The magnetic structure can be for example a magnetic shield or could be a magnetic pole of a write head and is particularly advantageous for use in a perpendicular recording system, because such perpendicular recording systems are especially susceptible to stray field writing. The magnetic structure includes a forward protruding portion that extends toward the air bearing surface (ABS) of the head also includes first and second wing portions that extend laterally from the forward protruding portion. The wing portions each have a front edge that is recessed from the ABS. The wings are tapered so that the amount of recess of the front edge of the wings increases with lateral distance from the center of the magnetic structure.
    Type: Application
    Filed: October 29, 2004
    Publication date: May 4, 2006
    Inventors: Kuok Ho, Yimin Hsu, Ching Tsang
  • Publication number: 20060082932
    Abstract: A read head has a bottom lead made of material that is relatively polish resistant and a top lead layer that polishes down more easily than the bottom layer. With this structure, when the layers are deposited and then polished down, the top layer recesses away from the sensor (and bottom lead layer) in a controlled fashion, providing an acceptable lead structure that reduces the mismatch between the read head physical read width and magnetic read width.
    Type: Application
    Filed: December 1, 2005
    Publication date: April 20, 2006
    Inventors: Marie-Claire Cyrille, Frederick Dill, Kuok Ho, Jui-Lung Li, Scott MacDonald, James Nix, Ching Tsang
  • Publication number: 20060067016
    Abstract: Current-perpendicular-to-the-plane (CPP), current-in-to-the-plane (CIP), and tunnel valve type sensors are provided having an antiparallel (AP) coupled free layer structure, an in-stack biasing structure which stabilizes the AP coupled free layer structure and a nonmagnetic spacer layer formed between the in-stack biasing layer and the AP coupled free layer structure. The AP coupled free layer structure has a first AP coupled free layer adjacent to the nonmagnetic spacer layer, a second AP coupled free layer, and an antiparallel coupling (APC) layer formed between the first and the second AP coupled free layers. The net moment of the AP coupled free layer structure has an antiparallel edge magnetostatic coupling with the in-stack biasing structure. At the same time, the first AP coupled free layer has an antiparallel exchange coupling with the second AP coupled free layer.
    Type: Application
    Filed: September 30, 2004
    Publication date: March 30, 2006
    Inventors: Jeffrey Childress, Robert Fontana, Kuok Ho, Ching Tsang
  • Publication number: 20060000079
    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: Application
    Filed: June 30, 2004
    Publication date: January 5, 2006
    Inventors: Meng Ding, Kuok Ho, Tsann Lin, Huey-Ming Tzeng
  • Publication number: 20050264944
    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: Application
    Filed: May 28, 2004
    Publication date: December 1, 2005
    Inventors: Robert Fontana, Kuok Ho, Ching Tsang
  • Publication number: 20050241138
    Abstract: A method of making a read sensor while protecting it from electrostatic discharge (ESD) damage involves forming a severable shunt during the formation of the read sensor. The method may include forming a resist layer over a plurality of read sensor layers; performing lithography with use of a mask to form the resist layer into a patterned resist which exposes left and right side regions over the read sensor layers as well as a shunt region; etching, with the patterned resist in place, to remove materials in the left and right side regions and in the shunt region; and depositing, with the patterned resist in place, left and right hard bias and lead layers in the left and right side regions, respectively, and in the shunt region for forming a severable shunt which electrically couples the left and right hard bias and lead layers together for ESD protection.
    Type: Application
    Filed: April 30, 2004
    Publication date: November 3, 2005
    Inventors: Frederick Dill, Meng Ding, Kuok Ho, Jordan Katine, Scott MacDonald, Huey-Ming Tzeng
  • Publication number: 20050243463
    Abstract: A magnetic head (slider) for perpendicular recording which requires no lapping is described. The head is fabricated with an air bearing surface that is parallel to the wafer surface. The coil and pole pieces are formed from thin films disposed parallel to the air bearing surface. Standard lithographic techniques can be used to define the shapes, gaps and pole piece dimensions. Non-rectilinear shapes can be formed; for example, side shields that conform around the write pole piece region. The thickness of the main and return pole pieces are controlled by the deposition process rather than by lapping. 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.
    Type: Application
    Filed: April 30, 2004
    Publication date: November 3, 2005
    Inventors: Robert Fontana, Kuok Ho, Ching Tsang
  • Publication number: 20050207073
    Abstract: A magnetically-coupled structure has two ferromagnetic layers with their in-plane magnetization directions coupled orthogonally across an electrically-conducting spacer layer that induces the direct orthogonal magnetic coupling. The structure has application for in-stack biasing in a current-perpendicular-to-the-plane (CPP) magnetoresistive sensor. One of the ferromagnetic layers of the structure is an antiparallel-pinned biasing layer and the other ferromagnetic layer is the sensor free layer. The antiparallel-pinned biasing layer has first and second ferromagnetic films separated by an antiferromagnetically-coupling film. An antiferromagnetic layer exchange-couples the first ferromagnetic film of the biasing layer to fix the net moment of the biasing layer parallel to the moment of the sensor pinned layer. This allows a single annealing step to be used to set the magnetization direction of the biasing and pinned layers.
    Type: Application
    Filed: May 27, 2004
    Publication date: September 22, 2005
    Inventors: Matthew Carey, Jeffrey Childress, Kuok Ho, Stefan Maat