Patents by Inventor Wipul Pemsiri Jayasekara

Wipul Pemsiri Jayasekara 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: 7623325
    Abstract: A method for providing an endpoint layer for ion milling of top of read sensor having top lead connection and sensor formed thereby. A cap layer includes a thin layer of an endpoint detection material, such as a conductive or insulating material, that is inserted in the cap layer. The endpoint detection material provides a good signal for endpoint detection during ion milling of the of the cap layer.
    Type: Grant
    Filed: September 29, 2005
    Date of Patent: November 24, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Wipul Pemsiri Jayasekara
  • Publication number: 20090246890
    Abstract: A method for manufacturing a magnetoresistive sensor that provides increased magnetoresistive performance. The method includes forming a series of sensor layers with at least one layer containing CoFeB, and having a first capping layer thereover. A high temperature annealing is performed to optimize the grains structure of the sensor layers. The first capping layer is then removed, such as by reactive ion etching (RIE). An antiferromagnetic layer is then deposited followed by a second capping layer. A second annealing is performed to set the magnetization of the pinned layer, the second annealing being performed at a lower temperature than the first annealing.
    Type: Application
    Filed: March 31, 2008
    Publication date: October 1, 2009
    Inventors: Hardayal Singh Gill, Wipul Pemsiri Jayasekara
  • Patent number: 7574791
    Abstract: A method for fabricating magnetic side shields for an MR sensor of a magnetic head. Following the deposition of MR sensor layers, a first DLC layer is deposited. Milling mask layers are then deposited, and outer portions of the milling mask layers are removed such that a remaining central portion of the milling mask layers is formed having straight sidewalls and no undercuts. Outer portions of the sensor layers are then removed such that a relatively thick remaining central portion of the milling mask resides above the remaining sensor layers. A thin electrical insulation layer is deposited, followed by the deposition of magnetic side shields. A second DLC layer is deposited and the remaining mask layers are then removed utilizing a chemical mechanical polishing (CMP) liftoff step. Thereafter, the first DLC layer and the second DLC layer are removed and a second magnetic shield layer is then fabricated thereabove.
    Type: Grant
    Filed: May 10, 2005
    Date of Patent: August 18, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Satoru Araki, Robert Stanley Beach, Marie-Claire Cyrille, Wipul Pemsiri Jayasekara, Quang Le, Jui-Lung Li, David John Seagle, Howard Gordon Zolla
  • Patent number: 7565733
    Abstract: An improved method for the manufacture of magnetoresistive multilayer sensors is disclosed. The method is particularly advantageous for the production of magnetic tunnel junction (MTJ) sensors, which can be damaged at the air bearing surface by conventional lapping and ion milling. The disclosed process protects the ABS of the magnetoresistive sensor by depositing a diamond like carbon layer which remains in place through ion milling. The DLC layer is removed by oxidation subsequent to the formation of the ABS.
    Type: Grant
    Filed: May 16, 2006
    Date of Patent: July 28, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Hardayal Singh Gill, Wipul Pemsiri Jayasekara, Huey-Ming Tzeng, Xiao Z. Wu
  • Patent number: 7562436
    Abstract: In one embodiment, a method of forming a CPP sensor comprises providing a sensor having a hard mask disposed on a left side thereof and a right side with a portion of the sensor material removed therefrom, the hard mask having a vertical surface; forming a right dielectric layer including a vertical surface disposed adjacent the vertical surface of the hard mask; forming a right hard bias layer or right side shields on the right dielectric layer; removing the hard mask to expose the left side of the sensor; forming an electrically conductive layer on the sensor, the electrically conductive layer including a vertical electrically conductive portion disposed adjacent the vertical surface of the right dielectric layer; removing the electrically conductive layer except the vertical electrically conductive portion; removing a portion of the sensor material from the left side of the sensor; forming a left dielectric layer on the left side of the sensor, the left dielectric layer including a vertical surface dispose
    Type: Grant
    Filed: July 29, 2005
    Date of Patent: July 21, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Wipul Pemsiri Jayasekara
  • 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
  • Publication number: 20090086385
    Abstract: A magnetoresistive sensor having a greatly reduced read gap. The sensor has a pinned layer structure formed above the free layer. A layer of antiferromagnetic material (AFM layer) is formed over the pinned layer structure and has a front edge disposed toward, but recessed from the air bearing surface. An electrically conductive, magnetic lead is formed over the pinned layer and AFM layer such that the lead fills a space between the AFM layer and the air bearing surface. In this way, the read gap is distance between the outermost portion of the pinned layer structure and free layer. The thickness of the AFM layer and capping layer are not included in the read gap.
    Type: Application
    Filed: September 27, 2007
    Publication date: April 2, 2009
    Inventors: Hardayal Singh Gill, Wipul Pemsiri Jayasekara
  • Publication number: 20090059437
    Abstract: A differential giant magnetoresistive sensor for sensing a magnetic signal. The differential sensor has a structure configured to minimize spin torque noise. The differential magnetoresistive sensor includes first and second magnetoresistive sensor elements and a three lead structure including an inner lead sandwiched between the first and second sensor elements and first and second outer leads. each of the sensor elements includes an antiparallel coupled free layer structure with the free layer of each of the sensor elements preferably being positioned near the inner lead. The three lead structure allows sense current to be supplied to the sensor such that electrons travel first through the free layer of each sensor element and then through the pinned layer structure.
    Type: Application
    Filed: September 5, 2007
    Publication date: March 5, 2009
    Inventors: Hardayal Singh Gill, Wipul Pemsiri Jayasekara
  • 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: 7444739
    Abstract: A magnetic head fabrication process in which a stencil layer is deposited upon a plurality of sensor layers. A photoresist mask in the desired read track width is fabricated upon the stencil layer. A reactive ion milling step is then conducted to remove the unmasked portions of the stencil layer. Where the stencil layer is composed of an organic compound, such as Duramide and/or diamond-like-carbon, a reactive ion milling step utilizing oxygen species produces a stencil of the present invention having exceptionally straight side walls with practically no undercuts. Thereafter, an ion milling step is undertaken in which the sensor layers that are not covered by the stencil are removed. The accurately formed stencil results in correspondingly accurately formed side walls of the remaining central sensor layers. A magnetic head sensor structure having a desired read track width and accurately formed side walls is thus fabricated.
    Type: Grant
    Filed: March 30, 2005
    Date of Patent: November 4, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Michael Feldbaum, Wipul Pemsiri Jayasekara, Mustafa Michael Pinarbasi
  • Patent number: 7446979
    Abstract: A magnetic head is disclosed having a CPP read head which produces reduced cross-track interference. The CPP read head includes a read sensor, a first shield and a second shield. The second shield has side drapes having an edge portion adjacent to the read sensor. The side drapes include a plurality of laminated layers which discourages formation of closure domains at the edge portions, and thus maintaining the side drapes in a state of high magnetic permeability. The laminated layers each include a magnetic layer and a non-magnetic spacer layer. Also disclosed is an edge closed lamination structure.
    Type: Grant
    Filed: September 30, 2004
    Date of Patent: November 4, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Wipul Pemsiri Jayasekara
  • Patent number: 7419610
    Abstract: A method for fabricating a read head sensor for a magnetic disk drive is presented. The method includes providing a layered wafer stack to be shaped, where the layered wafer stack includes a free layer, a barrier layer and a pinned layer. A single- or multi-layered photoresist mask is formed upon the layered wafer stack to be shaped. A material removal source is provided and used to perform a partial depth material removal within a partial depth material removal range which extends from the free layer to within the pinned layer to a partial depth material removal endpoint. In various embodiments, this depth endpoint lies at or within the barrier layer or within but not through the pinned layer.
    Type: Grant
    Filed: August 5, 2005
    Date of Patent: September 2, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Marie-Claire Cyrille, Ying Hong, Wipul Pemsiri Jayasekara
  • Publication number: 20080158736
    Abstract: A read head and a magnetic hard disk drive having a read head layer stack which has been partially milled to within a partial milling range to form a shaped junction and a hard bias layer which is in contact with the shaped junction of the wafer stack.
    Type: Application
    Filed: March 9, 2008
    Publication date: July 3, 2008
    Applicant: HITACHI GLOBAL STORAGE TECHNOLOGIES NETHERLANDS B. V.
    Inventors: Marie-Claire Cyrille, Wipul Pemsiri Jayasekara, Mustafa Michael Pinarbasi
  • Publication number: 20080151441
    Abstract: A magnetoresistive sensor having magnetically anisotropic bias layers for biasing the free layer of the sensor. The sensor includes a sensor stack with a pinned layer structure and a free layer structure and having first and second sides. Hard bias structures for biasing the magnetization of the free layer are formed at either side of the sensor stack, and each of the hard bias structure includes a hard magnetic layer that has a magnetic anisotropy to enhance the stability of the biasing. The hard bias structure can include a Cr under-layer having a surface that has been treated by a low power angled ion milling to form it with an anisotropic surface texture. A layer of Cr—Mo alloy is formed over the Cr under-layer and the hard magnetic material layer is formed over the Cr—Mo alloy layer. The anisotropic surface texture of the Cr layer induces an aligned crystalline structure in the hard magnetic layer that causes the hard magnetic layer to have a magnetic anisotropy.
    Type: Application
    Filed: December 22, 2006
    Publication date: June 26, 2008
    Inventors: James Mac Freitag, Mustafa Michael Pinarbasi, Wipul Pemsiri Jayasekara
  • 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: 7367110
    Abstract: A method for fabricating a read head for a magnetic disk drive having a read head sensor and a hard bias layer, where the read head has a shaped junction between the read head sensor and the hard bias layer. The method includes providing a layered wafer stack to be shaped. A single- or multi-layered photoresist mask having no undercut is deposited upon the layered wafer stack to be shaped. The layered wafer stack is shaped by the output of a milling source, where the shaping includes partial milling to within a partial milling range to form a shaped junction. A hard bias layer is then deposited which is in contact with the shaped junction of the wafer stack.
    Type: Grant
    Filed: September 27, 2004
    Date of Patent: May 6, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Marie-Claire Cyrille, Wipul Pemsiri Jayasekara, Mustafa Michael Pinarbasi
  • Patent number: 7332099
    Abstract: A method for reducing noise in a lapping guide. Selected portions of a magnetoresistive device wafer are bombarded with ions such that a magnetoresistive effect of lapping guides is reduced. The device is lapped, using the lapping guides to measure an extent of the lapping.
    Type: Grant
    Filed: October 6, 2005
    Date of Patent: February 19, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Mark A. Church, Wipul Pemsiri Jayasekara, Howard Gordon Zolla
  • Patent number: 7333300
    Abstract: A method for reducing noise in a lapping guide. Selected portions of a Giant magnetoresistive device wafer are masked, thereby defining masked and unmasked regions of the wafer in which the unmasked regions include lapping guides. The wafer is bombarded with ions such that a Giant magnetoresistive effect of the unmasked regions is reduced. The GMR device is lapped, using the lapping guides to measure an extent of the lapping.
    Type: Grant
    Filed: October 12, 2004
    Date of Patent: February 19, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Mark A. Church, Wipul Pemsiri Jayasekara, Howard Gordon Zolla
  • Patent number: 7329362
    Abstract: A method for constructing a magnetoresistive sensor which eliminates all redeposited material (redep) from the sides of the sensor. The method involves forming a mask over a plurality of sensor layers, and then performing an ion mill at an angle that is nearly normal to the surface of the sensor layers. A second (glancing) ion mill is then performed at a larger angle with respect to the normal. The first ion mill may be 0-30 degrees with respect to normal, whereas the second ion mill can be 50-89 degrees with respect to normal. The first ion mill is performed with a larger bias voltage than the second ion mill. The higher bias voltage of the first ion mill provides a well collimated ion beam to form straight vertical side walls. The lower bias voltage of the second ion mill prevent damage to the sensor layers during the removal of redep from the sides of the sensor.
    Type: Grant
    Filed: August 9, 2005
    Date of Patent: February 12, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Marie-Claire Cyrille, Ying Hong, Wipul Pemsiri Jayasekara
  • Publication number: 20070285849
    Abstract: A magnetic read head of either CIP or CPP configuration is disclosed having a read sensor having oxidized non-conductive regions. The read sensor has a front edge, a rear edge, a left-side edge and a right-side edge. For a CIP configuration, the front edge and the rear edge are oxidized to form non-conductive regions. For a CPP configuration, the left-side edge, the right-side edge, the front edge and the rear edge are oxidized to form non-conductive regions. Also disclosed are a disk drive including a read sensor having oxidized non-conductive regions, and a method of fabrication for a read sensor having oxidized non-conductive regions.
    Type: Application
    Filed: June 9, 2006
    Publication date: December 13, 2007
    Inventor: Wipul Pemsiri Jayasekara