Patents Assigned to Western Digital (Fremont), Inc.
  • Patent number: 6765756
    Abstract: The present invention provides an improved thin film write head and method of fabrication capable of providing an ultra-short yoke and/or an ultra-low conductor winding stack. The present invention reduces yoke length and stack height by forming the conductor winding in a trench etched from an insulation layer, preferably formed of an inorganic insulation material. A thin resist mask is used to define the width of the trench while the etch process defines the depth. Preferably, the insulation layer is formed on a different inorganic insulation material to control the etch process, thus, the conductor winding may be formed on the underlying layer. The conductor winding preferably is formed by depositing conductor material so that it fills the trench and then planarizing, such as by chemical mechanical polish, to remove conductor material deposited outside the trench.
    Type: Grant
    Filed: March 12, 1999
    Date of Patent: July 20, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Liubo Hong, Ronald A. Barr, Dashun Steve Zhou
  • Patent number: 6762910
    Abstract: The present invention provides a thin film read head having a lower shield pedestal with an adjacent lower extra gap layer. The pedestal may be formed from a lower shield layer with the lower extra gap layer being inset within the lower shield layer so that the top surfaces of the lower extra gap layer and the pedestal are generally planar. This allows for deposition of generally planar lower gap and sensor layers. A sensor element may be defined on the generally planar surface using a bilayer resist structure. The generally planar surface of the sensor layer inhibits resist pooling which could otherwise degrade resist structure and sensor element formation. In a typical embodiment, the read head of the present invention may have a spin valve type sensor element with leads electrically coupled to the sensor element, an upper gap layer extending between the sensor element and the upper shield layer, and an upper extra gap layer disposed between at least a portion of the leads and the upper shield layer.
    Type: Grant
    Filed: June 3, 1999
    Date of Patent: July 13, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Kenneth E. Knapp, Zi-Wen Dong, Ronald A. Barr, Russel Stearns, Bill Crue
  • Patent number: 6756071
    Abstract: A GMR spin valve is provided for reading a magnetic signal from a magnetic recording medium. The spin valve includes a non-magnetic layer such as for example copper, separated by first and second magnetic layers. The spin valve includes a pinned magnetic layer and a free magnetic layer, the resistance of the spin valve changing with the relative angle between the direction of magnetization of free and pinned layers. Extremely smooth surfaces are provided at the interfaces between the non-magnetic layer and the adjacent magnetic layers. This smooth interface greatly enhances the performance and reliability of the spin valve by allowing extremely tight control of the thickness of the non-magnetic layer and by preventing atomic diffusion between the non-magnetic and magnetic layers. This smooth interface is achieved by including a surfactant in the deposition of the non-magnetic layer.
    Type: Grant
    Filed: September 12, 2002
    Date of Patent: June 29, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Zhupei Shi, Ming Mao, Qunwen Leng
  • Patent number: 6754049
    Abstract: Perpendicular recording and magnetoresistive sensing transducers are disclosed having additional coil windings carrying current in an opposite direction to windings encircled by a core. The magnetic influence of the recording transducer on the sense transducer is reduced or eliminated. The inductance of the coils used to drive the recording transducer is reduced, facilitating high-frequency operation. Moreover, the magnetic flux induced by the coils and transmitted by the recording pole tip is increased, improving recording capabilities.
    Type: Grant
    Filed: October 16, 2001
    Date of Patent: June 22, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: David J. Seagle, Yugang Wang
  • Patent number: 6751055
    Abstract: An inductive transducer has inorganic nonferromagnetic material disposed in an apex region adjacent to a submicron nonferromagnetic gap in a magnetic core. The inorganic nonferromagnetic material has a much lower coefficient of thermal expansion than that of hardbaked photoresist, reducing pole tip protrusion even if other insulation surrounding the coil sections within the core is made of hardbaked photoresist. Alternatively, the entire insulation surrounding the coil sections within the core, in addition to the apex region, can be formed of inorganic nonferromagnetic material, further reducing pole tip protrusion. The transducer has SiO2 rather than alumina in an undercoat layer joining the wafer substrate and the thin film layers of the transducer. SiO2 may also replace alumina in other areas, such as a piggyback layer joining the inductive transducer with a magnetoresistive transducer.
    Type: Grant
    Filed: January 8, 2002
    Date of Patent: June 15, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Arshad Alfoqaha, Mohamad T. Krounbi, Sandrawattie Sankar, David J. Seagle, Kenneth R. Young
  • Patent number: 6747301
    Abstract: A tunneling barrier for a spin dependent tunneling (SDT) device is disclosed that includes a plurality of ferromagnetic atoms disposed in a substantially homogenous layer. The presence of such atoms in the tunneling barrier is believed to increase a magnetoresistance or &Dgr;R/R response, improving the signal and the signal to noise ratio. Such an increase &Dgr;R/R response also offers the possibility of decreasing an area of the tunnel barrier layer. Decreasing the area of the tunnel barrier layer can afford improvements in resolution of devices such as MR sensors and increased density of devices such as of MRAM cells.
    Type: Grant
    Filed: February 6, 2002
    Date of Patent: June 8, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Hugh Craig Hiner, Kyusik Sin, Shin Funada, Xizeng Shi, Hua-Ching Tong
  • Patent number: 6744608
    Abstract: A method and system for providing a tunneling magnetoresistive sensor is disclosed. The method and system include providing a pinned layer, a free layer and an insulating layer between the pinned and free layers. The pinned and free layers are ferromagnetic. The method and system also include providing a hard mask layer to be used in defining the sensor at the top of the tunneling magnetoresistive sensor. The method and system also include using the hard mask layer to define the tunneling magnetoresistive sensor. Thus, the pinned layer, the free layer and the insulating layer are capable of having a minimum dimension of less than 0.2 &mgr;m.
    Type: Grant
    Filed: May 14, 2002
    Date of Patent: June 1, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Kyusik Sin, Kristian M. Bjelland, Benjamin Chen, Hugh C. Hiner, Xizeng Shi
  • Patent number: 6735850
    Abstract: The present invention provides an improved bias magnet-to-magnetoresistive element interface and method of fabrication. In a preferred embodiment, the wall/walls of an MR element opposing a bias layer are formed by over etching to provide vertical side walls without taper. In the preferred embodiment, a protective element is formed over the MR element to protect it during etch processes. In some embodiments, a filler layer is deposited prior to bias layer formation. In CIP embodiments, any portion of the filler layer forming on vertical side walls of the MR element is etched to provide an exposed side wall surface for contiguous bias layer formation. In CPP embodiments, the filler layer forms on a vertical back wall and electrically insulates the MR element from the bias layer.
    Type: Grant
    Filed: May 20, 2002
    Date of Patent: May 18, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Matthew Gibbons, Kenneth E. Knapp, Ronald A. Barr, Benjamin P. Law, James Spallas, Ming Zhao
  • Patent number: 6737281
    Abstract: A method of making an inductive transducer having inorganic nonferromagnetic material disposed in an apex region adjacent to a submicron nonferromagnetic gap in a magnetic core. The inorganic nonferromagnetic apex region can be made by chemical etching of a layer of inorganic nonferromagnetic material, deposition of inorganic nonferromagnetic material through a mask that is then lifted-off, or anisotropic etching of a layer of inorganic nonferromagnetic material that is covered by a hardbaked photoriesist mask.
    Type: Grant
    Filed: January 8, 2002
    Date of Patent: May 18, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Xiaozhong Dang, Yingjian Chen, Aiguo Feng
  • Patent number: 6724569
    Abstract: Embodiments in accordance with the thin film write head of the present invention have a lower pole structure, an upper pole structure, and a multilayer write gap extending from an air bearing surface between the upper and lower pole structures. In preferred embodiments, the write gap comprises at least two of: (a) a first layer covering a lower pole tip portion of the lower pole structure, (b) a second layer covering turns of a semiconductor winding, or (c) a third layer covering a winding insulation stack. In more preferred embodiments, the write gap is formed of the first, the second, and the third write gap layers. An advantage of a write head with a multilayer write gap is that it allows better control of write gap thickness. As such, loss of write gap thickness can be compensated for by deposition of the second write gap layers, or by deposition of the third write gap layer.
    Type: Grant
    Filed: August 23, 2002
    Date of Patent: April 20, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Yingjian Chen, Kyusik Sin, Ronald A. Barr
  • Patent number: 6721149
    Abstract: A method and system for providing a magnetoresistive sensor that reads data from a recording media is disclosed. The method and system include providing an antiferromagnetic layer, providing a pinned layer without adversely affecting performance of the magnetoresistance sensor, providing a free layer, and providing an insulating spacer layer disposed between the pinned layer and the free layer. The pinned layer is magnetically coupled to the antiferromagnetic layer. The pinned layer is also a half metallic ferromagnet. The free layer is ferromagnetic. The insulating spacer layer is sufficiently thin to allow tunneling of charge carriers between the pinned layer and the free layer. Furthermore, the insulating spacer layer allows for d-bonding between a portion of the insulating layer and a portion of the free layer and pinned layer layer.
    Type: Grant
    Filed: February 11, 2000
    Date of Patent: April 13, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Zhupei Shi, Qun Wen Leng, Zi-Weng Dong
  • Patent number: 6721203
    Abstract: A reference cell circuit for a magnetic tunnel junction MRAM includes a first magnetic tunnel junction device set to a low resistance state and a second magnetic tunnel junction device set to a high resistance state. A reference cell series unit includes the first magnetic tunnel junction device electrically coupled in series with the second magnetic tunnel junction device. The reference cell series unit further has a first end and a second end with the first end being electrically coupled to a first current source and the second end being electrically coupled to a current sink and a second current source.
    Type: Grant
    Filed: December 12, 2001
    Date of Patent: April 13, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Qiuqun Qi, Xizeng Shi, Matthew R. Gibbons
  • Patent number: 6721142
    Abstract: A slider (34) for reading data from a disk surface (80), the slider (80) including a magneto-resistive head (36). The head (36) includes a transducer (58) having a stack of layers (59), each layer (62,66,70,74) having a proximal end (64,68,72,76) proximal to the disk surface, and a pair of electrical leads (82), connected to the transducer (58), each one of the electrical leads (82) also having a proximal end (83) proximal to the disk surface (80). At least one of the proximal ends (83) of the electrical leads (82) and the layers (66) is recessed to provide one or more recessed areas (92). The recessed areas (92) are then filled with protective material (94) to a depth such that when the layer of protective material (48) is worn from the proximal ends (64,68,72,76,83) by burnishing by the disk surface (80), protective material (94) still remains in the recessed areas (92).
    Type: Grant
    Filed: December 21, 2000
    Date of Patent: April 13, 2004
    Assignee: Western Digital (Fremont) Inc.
    Inventors: Dallas W. Meyer, Tien-Chih Lin, Michael A. Stacy
  • Patent number: 6721138
    Abstract: An inductive transducer having first and second magnetic pedestals disposed between first and second magnetic pole layers and adjacent to a media-facing surface, the pedestals separated by a submicron, nonmagnetic gap. The first pedestal extends less than the second pedestal from the media-facing surface, defining a short throat height. The second pedestal extends further to provide sufficient area for stitching to the second pole layer. The stitching and the thickness provided by the pedestals allow plural coil layers to be disposed between the pole layers, and the second pedestal, as well as other features, can be defined by high-resolution photolithography. The two coil layers have lower resistance, lower inductance and allow the pole layers to be shorter, improving performance. All or part of either or both of the pedestals may be formed of high magnetic saturation material, further enhancing performance.
    Type: Grant
    Filed: October 24, 2001
    Date of Patent: April 13, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Yingjian Chen, Xizeng Shi, Hugh Craig Hiner, Zi-Wen Dong, Francis Liu, Matthew R. Gibbons, Joyce Anne Thompson, William D. Jensen, Chester Xiaowen Chien, Yugang Wang
  • Patent number: 6717773
    Abstract: Windage proximate to a spinning disk within a disk drive is directed through a plurality of apertures in a ramp situated near the outside diameter of the disk. A tab extending from a load beam that supports a slider rests on the ramp when the drive is not in use. When the drive is started the disk begins to spin and an actuator moves the load beam to bring the slider over the surface of the disk. As the load beam moves, the tab is guided along the ramp and cushioned by the air flow emerging from apertures in the ramp beneath it. When the drive is stopped the actuator brings the load beam back so that the tab engages the ramp. A cushion of air is again provided as the tab is moved along the ramp as the tab is returned to a parked position.
    Type: Grant
    Filed: June 24, 2002
    Date of Patent: April 6, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Muhammad A. Hawwa, Jamshid Bozorgi, Aric Menon
  • Patent number: 6713801
    Abstract: A method and system for providing a tunneling junction is disclosed. The method and system includes providing a free layer, a pinned layer, and a barrier between the free layer and the pinned layer. The free layer and the pinned layer are ferromagnetic. The barrier layer is an insulator. The magnetic tunneling junction is coupled to an &agr;-Ta lead.
    Type: Grant
    Filed: July 9, 2002
    Date of Patent: March 30, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Kyusik Sin, Hugh C. Hiner, Xizeng Shi
  • Patent number: 6708389
    Abstract: A method of making a magnetic head suspension assembly includes attaching a slider with a magnetic head to an intermediate flexible circuit. The attached combination is then inserted into a spin stand tester for the testing of electrical performance. If the attached combination fails the test, it is discarded, thereby avoiding the cost of discarding an entire head suspension assembly. On the other hand, if the attached combination passes the test, it is mounted to a load beam to form the head suspension assembly. Thereafter, a flex circuit can be attached to the load beam and intermediate flexible circuit to provide electrical connections to the magnetic head through the intermediate flexible circuit.
    Type: Grant
    Filed: July 10, 2000
    Date of Patent: March 23, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Carl J. Carlson, Daniel P. Schott
  • Patent number: 6707083
    Abstract: A method and system for providing a magnetic tunneling junction is disclosed. The method and system includes providing a free layer, a pinned layer, and a barrier between the free layer and the pinned layer. The free layer and the pinned layer are ferromagnetic. The barrier layer is an insulator. The magnetic tunneling junction is coupled to a bit line. The bit line includes a ferromagnetic liner and a nonmagnetic core. The nonmagnetic core includes a top, a bottom and sides. The ferromagnetic liner includes at least one tab and is adjacent to the sides and a portion of the bottom of the nonmagnetic core. The at least one tab is adjacent to the portion of the bottom of the nonmagnetic core.
    Type: Grant
    Filed: July 9, 2002
    Date of Patent: March 16, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Hugh C. Hiner, Kyusik Sin, Matthew Gibbons, Xizeng Shi
  • Patent number: 6704173
    Abstract: A method and system for providing a suspension assembly for protecting a magnetoresistive (MR) head from electrostatic discharge damage is disclosed. The MR head includes an MR sensor having a first end and a second end. The method and system include providing a first lead and a second lead and providing an insulating film substantially supporting a first portion of the first lead and a second portion of the second lead. The MR head is coupled with the suspension assembly. The first and second ends of the MR sensor are coupled with the first and second leads, respectively. The method and system include providing a conductive strip coupled with the insulating film. In one aspect, the method and system include providing at least one diode electrically coupling the first lead and the second lead. In another aspect, the method and system also include electrically coupling first lead with the conductive strip.
    Type: Grant
    Filed: August 16, 2000
    Date of Patent: March 9, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Chung Fai Lam, Gary Lloyd Crown, Seila Chao Chim
  • Patent number: 6704158
    Abstract: A head gimbal assembly for a disk drive. The head gimbal assembly includes a load beam defining a longitudinal axis. The head gimbal assembly further includes a flexure with a portion of said flexure being attached to said load beam. The head gimbal assembly further includes a slider including a read/write head. The head gimbal assembly further includes a collocated microactuator which connects between said flexure and said slider for providing pure or nearly pure lateral movement to said slider in a plane of motion that includes the longitudinal axis. The collocated microactuator is a shear mode piezoelectric motor and disposed between the slider and the load beam along an axis disposed orthogonal to the longitudinal axis.
    Type: Grant
    Filed: June 5, 2001
    Date of Patent: March 9, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Muhammad A. Hawwa, Edmund B. Fanslau, Kenneth F. Young