Patents Assigned to Western Digital (Fremont), Inc.
  • Patent number: 6833979
    Abstract: The present invention provides an improved current perpendicular to the plane thin film read head device and method of fabrication. With the present invention, the lower lead is formed to inhibit accumulation of redeposited lead material on CPP sensor element side walls during CPP sensor formation. In the preferred embodiment, the upper portion of the lower lead, which normally is etched during sensor element formation, is formed of a low sputter yield material to reduce redeposition flux to the sensor side walls. It is also preferred to form the upper portion of a material that also has a low value for the ratio of its sputter yield at the lead milling angle-to-its sputter yield at the side wall milling angle to inhibit redeposition accumulation on the side wall. It is preferred to clad conventional lead material with a low sputter yield ratio, low resistivity material, to inhibit side wall redeposition accumulation while also providing a low resistance lower lead.
    Type: Grant
    Filed: June 21, 2002
    Date of Patent: December 21, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Kenneth E. Knapp, Ronald A. Barr, Lien-Chang Wang, Benjamin P. Law, James Spallas
  • Patent number: 6829819
    Abstract: A magnetoresistive device having a first pole, a second pole, and a first tapered pole pedestal therebetween and magnetically connected to the second pole. The first tapered pole has a width that increases with increasing distance away from the air bearing surface, ABS. The magnetoresistive device can also include a second tapered pole pedestal magnetically connected to the first pole, and separated from the first tapered pole pedestal by a write gap. The second tapered pole pedestal has a width that increases with increasing distance away from the air bearing surface. A method of the present invention includes defining the trackwidth of a write element by lapping a tapered pole pedestal. More specifically, the trackwidth is given by a known taper angle, a zero throat width, and a throat height, wherein the throat height is controlled precisely by lapping.
    Type: Grant
    Filed: December 11, 2001
    Date of Patent: December 14, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Billy W. Crue, Jr., Mark David Thomas, Zhupei Shi, Renuka Apparao
  • Patent number: 6829160
    Abstract: A magnetic random access memory (MRAM) cell and a memory array formed from the MRAM cells are disclosed. The MRAM cell includes a magnetic tunneling junction and a transistor. The magnetic tunneling junction includes a first ferromagnetic layer, a second ferromagnetic layer and an insulating layer between the first ferromagnetic layer and the second ferromagnetic layer. The gate of the transistor is coupled to a first end of the magnetic tunneling junction. The source of the transistor is coupled to a second end the magnetic tunneling junction. The drain of the transistor is coupled with an output for reading the magnetic memory cell. During reading, a read current is applied to the magnetic tunneling junction and the transistor is preferably operated in a saturation region.
    Type: Grant
    Filed: February 20, 2002
    Date of Patent: December 7, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Quiqun (Kevin) Qi, Xizeng (Stone) Shi, Matthew Gibbons
  • Patent number: 6828897
    Abstract: A method for maximizing the interfacial properties of magnetoresistive sensors, such as spin valve and GMR sensors used in storage devices, comprises selecting the materials for ferromagnetic layers and for electrically conductive spacers that are interposed between the ferromagnetic layers. The electronegativities of the selected materials are substantially matched so that an absolute value of the differences in electronegativities is minimized. The conductive spacer material provides a relatively low resistivity and a large mean free path. The sensors experience greater chemical and thermal stability, are corrosion resistant, and realize an increased signal output.
    Type: Grant
    Filed: August 3, 1998
    Date of Patent: December 7, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventor: Daniel A. Nepela
  • Patent number: 6816345
    Abstract: Methods for reducing feature sizes of devices such as electromagnetic sensors are disclosed. A track width of a MR sensor is defined by a mask having an upper layer with a reduced width and a lower layer with a further reduced width. Instead of or in addition to being supported by the lower layer in the area defining the sensor, the upper layer is supported by the lower layer in areas that do not define the sensor width. In some embodiments the upper layer forms a bridge mask, supported at its ends by the lower layer, and the lower layer is completely removed over an area that will become a sensor. Also disclosed is a mask having more than two layers, with a bottom layer completely removed over the sensor area, and a middle layer undercut relative to a top layer.
    Type: Grant
    Filed: September 24, 2001
    Date of Patent: November 9, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Kenneth E. Knapp, Ronald A. Barr, Myron R. Cagan, Mark D. Thomas
  • Patent number: 6809899
    Abstract: Electromagnetic transducers are disclosed having write poles with a leading edge that is smaller than a trailing edge, which can reduce erroneous writing for perpendicular recording systems. The write poles may have a trapezoidal shape when viewed from a direction of an associated medium. The write poles may be incorporated in heads or sliders that also contain read elements such as magnetoresistive sensors, and may be employed with information storage systems such as disk drives.
    Type: Grant
    Filed: December 31, 2003
    Date of Patent: October 26, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Yingjian Chen, Yugang Wang, Francis Liu, Xizeng Shi, Kyusik Sin, Hugh Craig Hiner
  • Patent number: 6807332
    Abstract: An optical switching component comprises a rotor with a reflective top surface pivotally mounted within a stator, and a piezoelectric actuator set between the rotor and the stator to move the rotor about the pivot point. A controller can also be joined to the piezoelectric actuator to effectuate actuation thereof. Two light ports can also be set proximate to the reflective top surface such that a beam of light emitted from one is reflected to the other. Multiple optical switching components can be arranged to form an optical switching device. Optical switching components and devices can be fabricated according to conventional microfabrication practices including film deposition, planarization, and photolithography techniques.
    Type: Grant
    Filed: June 19, 2001
    Date of Patent: October 19, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventor: Muhammad A. Hawwa
  • Patent number: 6807030
    Abstract: An actuator is coupled between a head and flexure and gimbal elements, the actuator providing submicron positioning of the head while reducing undesirable vibrations of the flexure and gimbal elements. Such an actuator may have a frame that surrounds a cavity, the frame having an opening disposed adjacent to the head and a wall disposed on an opposite side of the frame from the opening. One or more active elements are disposed in the cavity and attached to the frame, the active element separated from the wall and having a dimension that varies in size in response to a control signal, with a moveable element coupled to the active element and to the head.
    Type: Grant
    Filed: December 18, 2001
    Date of Patent: October 19, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Muhammad A. Hawwa, Edmund B. Fanslau, Jr.
  • Patent number: 6806035
    Abstract: A serialization process presents an efficient method of creating serial numbers on a ceramic-like semiconductor wafer by forming a non-rigid photomask that incorporates character specifications for the serial numbers. The non-rigid photomask is retained in a rigid, optically transparent photomask holder that enables the photomask to be handled as a rigid structure. Upon preparation of the wafer, the serial numbers are created onto wafer dies using a combined process involving photolithography, and a reactive ion etching process with a selective etch rate. The serialization process enables a rapid creation of serial numbers, with the selective RIE process substantially increasing the optical contrast of the characters without the need for deep trenches and without generation of excessive debris.
    Type: Grant
    Filed: June 25, 2002
    Date of Patent: October 19, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Thanawatana Atireklapvarodom, Richard D. Anderson
  • Patent number: 6803615
    Abstract: An MRAM cell includes a pinned layer, a free layer, and a bit line with a magnetic sheath. The magnetic sheath allows a magnetic field to circulate in a loop around the bit line. The looping magnetic field can couple with the magnetic field of the free layer for enhanced stability with respect to stray magnetic fields and elevated temperatures.
    Type: Grant
    Filed: December 14, 2001
    Date of Patent: October 12, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Kyusik Sin, Xizeng Shi, Hugh Craig Hiner
  • Patent number: 6801408
    Abstract: In at least one embodiment, the apparatus of the invention is a read sensor which includes a shield, a sensor element, a read gap positioned between the shield and the sensor element, and an extra gap positioned between the shield and the sensor element and adjacent the read gap. The sensor element is positioned in a sensor layer. With the sensor element and the shield separated by only the relatively thin gap layer, high sensitivity of the sensor element is obtained. Further, by placing the relatively thick extra gap between the shield and the sensor layer and about the sensor element, the potential for shorting is minimized. The shield can be planarized to keep the read gap and the sensor layer at, and about, the sensor element substantially planar. This, in turn, results in improved control of sensor track widths and greatly reduces the potential for pooling of photoresist.
    Type: Grant
    Filed: November 2, 2000
    Date of Patent: October 5, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Yingjian Chen, Ronald A. Barr, Hau-Ching Tong
  • Patent number: 6801411
    Abstract: A dual-stripe current-pinned spin valve magnetoresistive read sensor includes a first soft ferromagnetic (FM) layer separated from a second soft FM layer by a first spacer layer formed of conductive material. The first spacer layer is also configured to receive a first biasing current for generating a first magnetic field of sufficient strength to saturate the first soft FM layer. The read sensor further includes a third soft FM layer and a fourth soft FM layer separated by a second spacer layer formed of conductive material. The second spacer layer is configured to receive a second biasing current for generating a second magnetic field of sufficient strength to saturate the fourth soft FM layer. An insulation layer also is disposed between the second soft FM layer and the third FM layer.
    Type: Grant
    Filed: February 10, 1999
    Date of Patent: October 5, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Marcos Lederman, Matthew R. Gibbons
  • Patent number: 6798625
    Abstract: The present invention provides a spin-valve magnetoresistance sensor in which are formed, on top of the substrate, free layers, and pinned layers, enclosing a nonmagnetic spacer layer, and an antiferromagnetic layer adjacent to the pinned layers. The sensor is also equipped with a back layer including at least two nonmagnetic metal layers adjacent to the free layers on the side of the free layers opposite the nonmagnetic spacer layer. The back layer has at least one nonmagnetic metal layer of Cu with high electrical conductivity, preferably formed adjacent to the free layers, as for example in a two-layer structure of Cu and Ru or a three-layer structure Ru/Cu/Ru. In addition to a high read output, fluctuations in Hint with the film thickness of the back layer can be suppressed and sensor characteristics stabilized, and high recording densities can be realized.
    Type: Grant
    Filed: September 26, 2000
    Date of Patent: September 28, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Masaki Ueno, Kiyotaka Tabuchi, Tatsuo Sawasaki, Hiroshi Nishida, Kazuhiro Mizukami, Fuminori Hikami
  • Patent number: 6798616
    Abstract: A disk drive write head having in consecutive layers a bottom pole, a write gap layer, a first insulation layer, a coil, a second insulation layer having an insulation layer boundary, and a top pole on the second insulation layer. The top pole includes a main body portion and a nose portion and has a flare line at the location where the nose portion expands to become the main body portion. The top pole further includes a curved contour portion having a contour boundary, a tip which terminates in an air bearing surface, and a flat portion on the top surface of the nose extending between the tip and the contour boundary. The insulation layer boundary is recessed from the air bearing surface such that the top pole contour boundary lies substantially close to the flare line, thus producing a top pole top surface which is substantially flat.
    Type: Grant
    Filed: July 10, 2001
    Date of Patent: September 28, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: David J. Seagle, Qing He, Lien-Chang Wang, Ming Zhao
  • Patent number: 6796018
    Abstract: A slider/suspension design and assembly method include securing a slider to a suspension assembly for use in a magnetic disk drive data recording device. To this end, a solder fillet bond is applied at the leading edge surface of the slider to provide a structural connection of the slider to the flexure, while also enabling the slider-suspension assembly to be separated without damage during the process. The slider/suspension assembly is initiated by forming a plurality of sliders on a wafer, in such a manner that the trailing edge surfaces of the sliders form the front side of the wafer, and the leading edge surfaces of the sliders form the backside of the wafer. A plurality of thin film data transducing elements and a plurality of electrical contact pads are then formed on the wafer front side.
    Type: Grant
    Filed: December 21, 2001
    Date of Patent: September 28, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventor: Brian Scott Thornton
  • Publication number: 20040184194
    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: Application
    Filed: January 27, 2004
    Publication date: September 23, 2004
    Applicant: Western Digital (Fremont), Inc.
    Inventors: Muhammad A. Hawwa, Jamshid Bozorgi, Aric Menon
  • Patent number: 6791793
    Abstract: A read/write head and method of making the same, are used in a data storage system, such as a disk drive, for perpendicular magnetic recording of data. The head employs a two-layer pole design with a main pole made of sputtered high moment magnetic material, and an adjunct pole made of electroplated soft magnetic film. The adjunct pole is substantially recessed from the air bearing surface. The present head design significantly enhances the magnetic write field, and substantially reduces side-writing that result in accidental erasure of data in adjacent tracks on the magnetic recording medium.
    Type: Grant
    Filed: September 14, 2001
    Date of Patent: September 14, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Yingjian Chen, Xiaozhong Dang, Francis H. Liu, Kroum Stoev, Hai Jiang, Yugang Wang, Xizeng Shi
  • Patent number: 6785955
    Abstract: A method and system for providing a writer is disclosed. The method and system include providing a first pole, an insulator covering a portion of the first pole and a coil on the first insulator. The coil includes a plurality of turns. The method and system also include providing a second insulator covering the coil, providing a second pole on the second insulator and providing a write gap separating a portion of the first pole from a second portion of the second pole. A first portion of the second pole is coupled with the first pole. In one aspect, the method and system include providing a coil having a plurality of turns with a pitch of no more than 1.2 micrometers. In another aspect, the plurality of turns of the coil is provided using a hard mask layer on a photoresist layer. A portion of the hard mask layer and a portion of the photoresist layer define a plurality of spaces between the pluralities of turns of the coil. In another aspect, the writer is a pedestal defined zero throat writer.
    Type: Grant
    Filed: January 23, 2001
    Date of Patent: September 7, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Yingjian Chen, Hugh Craig Hiner, Benjamin Chen, Xizeng Shi, Kyusik Sin
  • Patent number: 6775902
    Abstract: A magnetic head is fabricated by providing a substrate with a planar surface, forming at least one cavity in the planar substrate, depositing a second yoke layer in the cavity, forming a second pole tip in the cavity in contact with the second yoke layer, patterning an inductive coil in the cavity, depositing a gap layer over the second pole tip, sputtering a first pole tip over the gap layer, etching the first and second pole tips and the gap layer to form a stack of layers, depositing a protective layer over the stack of layers, leveling the protective layer to expose the first pole tip, and patterning a first yoke layer in contact with the first pole tip.
    Type: Grant
    Filed: June 9, 2000
    Date of Patent: August 17, 2004
    Assignee: Western Digital (Fremont) Inc.
    Inventors: Yiming Huai, Durga P. Ravipati, Mark D. Thomas, Carlos Corona, William D. Jensen
  • Patent number: 6778358
    Abstract: In one aspect, a laminated structure including a first plurality of layers containing primarily-iron FeCoN interleaved with a second plurality of layers containing primarily iron FeNi is disclosed. The structure has an easy axis of magnetization and a hard axis of magnetization, has a magnetic saturation of at least about twenty-three-thousand Gauss, and has a magnetic coercivity measured substantially along its hard axis of magnetization that is less than two Oersted. Additional elements can be added in minority concentrations to form primarily-iron FeCoN layers with increased resistivity. The laminated structure has applicability in various fields in which high saturation magnetization, magnetically soft materials are advantageous, particularly for inductive heads.
    Type: Grant
    Filed: May 1, 2002
    Date of Patent: August 17, 2004
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Hai Jiang, Yingjian Chen, Xiaozhong Dang, Mohamad T. Krounbi