Patents by Inventor Wipul Jayasekara

Wipul 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: 7103963
    Abstract: A magnetic tunnel junction (MTJ) sensor in which the free layer longitudinal biasing elements are coupled, without insulation, to the free layer outside of the MTJ stack to provide reliable non-shunting MTJ free layer stabilization without extremely thin dielectric layers. In one embodiment, hard magnetic (HM) layers are disposed in contact with the free layer outside of and separated from the MTJ stack active region by a thick dielectric layer. In another embodiment, antiferromagnetic (AFM) bias layers are disposed in contact with the free layer outside of and separated from the MTJ stack active region by a thick dielectric layer. In other embodiments, nonconductive HM layers are disposed either in contact with the free layer outside of the MTJ stack active region and/or in abutting contact with the MTJ stack active region.
    Type: Grant
    Filed: June 30, 2003
    Date of Patent: September 12, 2006
    Assignee: Hitachi Global Storage Technologies
    Inventor: Wipul Jayasekara
  • Publication number: 20060158790
    Abstract: A magnetoresistive sensor having improved pinned layer stability at small track widths. The sensor has substantially vertical side walls that define the track width of the sensor. The free layer terminates at the substantially vertical side walls, but the pinned layer structure or a portion thereof extends beyond the track width region into the field. The extended pinned layer structure provides improved resistance to amplitude flipping, while allowing the track width to remain small.
    Type: Application
    Filed: January 14, 2005
    Publication date: July 20, 2006
    Inventors: James Freitag, Wipul Jayasekara, Mustafa Pinarbasi
  • Publication number: 20060132969
    Abstract: A magnetic head, comprising a read sensor formed in a central region, the read sensor including a free layer; an etch-stop layer formed over the free layer; and a capping layer formed over the free layer.
    Type: Application
    Filed: December 12, 2005
    Publication date: June 22, 2006
    Inventor: Wipul Jayasekara
  • Publication number: 20060101636
    Abstract: A method for constructing a magnetoresistive sensor using an etch mask that is resistant to the material removal process used to define the sensor width and stripe height. The method may include the use of a Ta etch mask formed under a photoresist mask, and the use of an ion milling process to define the sensor. The etch mask remains substantially intact after performing the ion milling and therefore is readily removed by a later CMP process. The etch mask layer is also very resistant to high temperatures such as those used in a desired atomic layer deposition of alumina, which is used to deposit conformal layers of alumina around the sensor.
    Type: Application
    Filed: November 18, 2004
    Publication date: May 18, 2006
    Inventors: Marie-Claire Cyrille, Elizabeth Dobisz, Wipul Jayasekara, Jui-Lung Li
  • Publication number: 20060098334
    Abstract: A perpendicular write head is disclosed for writing information onto tracks. The write head includes a top pole and a return pole and side shields with laminated layers wherein said laminated layers have magnetization in a direction parallel to an air bearing surface (ABS) and perpendicular to the tracks.
    Type: Application
    Filed: October 27, 2004
    Publication date: May 11, 2006
    Inventors: Wipul Jayasekara, Hardayal Gill
  • Patent number: 7035063
    Abstract: A magnetic tunnel junction (MTJ) sensor in which the free layer longitudinal biasing elements are coupled, without insulation, to the free layer outside of the MTJ stack to provide reliable non-shunting MTJ free layer stabilization without extremely thin dielectric layers. In one embodiment, hard magnetic (HM) layers are disposed in contact with the free layer outside of and separated from the MTJ stack active region by a thick dielectric layer. In another embodiment, antiferromagnetic (AFM) bias layers are disposed in contact with the free layer outside of and separated from the MTJ stack active region by a thick dielectric layer. In other embodiments, nonconductive HM layers are disposed either in contact with the free layer outside of the MTJ stack active region and/or in abutting contact with the MTJ stack active region.
    Type: Grant
    Filed: July 16, 2003
    Date of Patent: April 25, 2006
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Wipul Jayasekara
  • Publication number: 20060067005
    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: Application
    Filed: September 30, 2004
    Publication date: March 30, 2006
    Inventor: Wipul Jayasekara
  • Publication number: 20060067009
    Abstract: A method is disclosed 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. A read head and a magnetic hard disk drive having a read head layer stack which has been partially milled are also disclosed.
    Type: Application
    Filed: September 27, 2004
    Publication date: March 30, 2006
    Inventors: Marie-Claire Cyrille, Wipul Jayasekara, Mustafa Pinarbasi
  • Publication number: 20060043280
    Abstract: A system for improving drift compensation for ion mill applications defines a reference step for purposes of time duration. The reference step is controlled by an end point detector and monitored for use with subsequent process steps. The time duration for a subsequent step is adjusted as a percentage of the reference step. A time scaling factor determines the actual duration of the subsequent step. Rather than directly using times of step duration, the system uses a percentage of the reference step for the latter step. The duration of the reference step varies depending on the tool drift. The overall duration is changed in the same proportion as the duration of the reference step, and thereby compensates for the influence of drift on the end product.
    Type: Application
    Filed: August 30, 2004
    Publication date: March 2, 2006
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Michael Feldbaum, Hung-Chin Guthrie, Wipul Jayasekara, Aron Pentek
  • Publication number: 20060027528
    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.
    Type: Application
    Filed: October 6, 2005
    Publication date: February 9, 2006
    Inventors: Mark Church, Wipul Jayasekara, Howard Zolla
  • Publication number: 20050269288
    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: Application
    Filed: August 9, 2005
    Publication date: December 8, 2005
    Inventors: Marie-Claire Cyrille, Ying Hong, Wipul Jayasekara
  • Publication number: 20050237666
    Abstract: A magnetoresistive read/write head having a first layer of alumina and a second layer of silicon dioxide overlaying a P3 layer of the head. In a preferred embodiment, the silicon dioxide layer is recessed away from an Air Bearing Surface (ABS) to reduce protrusion of a P2 layer and the P3 layer in the head, and to reduce degradation in the magnetic properties of the pole tips of the P2 and P3 layer ends.
    Type: Application
    Filed: April 26, 2004
    Publication date: October 27, 2005
    Inventors: Wen-Chien Hsiao, Wipul Jayasekara, Edward Lee, Vladimir Nikitin, Patrick Webb, Sue Zhang
  • Publication number: 20050185332
    Abstract: A magnetic structure, such as a pole tip, and method for forming the same includes forming a pole tip layer of magnetic material. A layer of polyimide precursor material is added above the pole tip layer and cured. A silicon-containing resist layer is added above the layer of polyimide precursor material and patterned. The resist layer is exposed to oxygen plasma for converting the resist into a glass-like material. Exposed portions of the cured polyimide precursor material are removed for exposing portions of the pole tip layer. The exposed portions of the pole tip layer are removed for forming a pole tip. Chemical mechanical polishing (CMP) can then be performed to remove any unwanted material remaining above the pole tip.
    Type: Application
    Filed: June 30, 2004
    Publication date: August 25, 2005
    Inventors: Richard Hsiao, Wipul Jayasekara, Jeffrey Lille
  • Publication number: 20050184840
    Abstract: A magnetic structure, such as a pole tip, and method for forming the same includes forming a pole tip layer of magnetic material. A layer of polyimide precursor material is added above the pole tip layer and cured. A silicon-containing resist layer is added above the layer of polyimide precursor material and patterned. The resist layer is exposed to oxygen plasma for converting the resist into a glass-like material. Exposed portions of the cured polyimide precursor material are removed for exposing portions of the pole tip layer. The exposed portions of the pole tip layer are removed for forming a pole tip. Chemical mechanical polishing (CMP) can then be performed to remove any unwanted material remaining above the pole tip.
    Type: Application
    Filed: June 30, 2004
    Publication date: August 25, 2005
    Inventors: Richard Hsiao, Wipul Jayasekara, Jeffrey Lille
  • Patent number: 6930866
    Abstract: A magnetic tunnel junction (MTJ) sensor in which the free layer longitudinal biasing elements are coupled, without insulation, to the free layer outside of the MTJ stack to provide reliable non-shunting MTJ free layer stabilization without extremely thin dielectric layers. In one embodiment, hard magnetic (HM) layers are disposed in contact with the free layer outside of and separated from the MTJ stack active region by a thick dielectric layer. In another embodiment, antiferromagnetic (AFM) bias layers are disposed in contact with the free layer outside of and separated from the MTJ stack active region by a thick dielectric layer. In other embodiments, nonconductive HM layers are disposed either in contact with the free layer outside of the MTJ stack active region and/or in abutting contact with the MTJ stack active region.
    Type: Grant
    Filed: July 16, 2003
    Date of Patent: August 16, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Wipul Jayasekara
  • Publication number: 20050063101
    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.
    Type: Application
    Filed: October 12, 2004
    Publication date: March 24, 2005
    Inventors: Mark Church, Wipul Jayasekara, Howard Zolla
  • Publication number: 20050045580
    Abstract: A method for milling a structure. A single- or multi-layer resist having no undercut is added to a surface of a structure to be milled, the surface to be milled defining a plane. A milling process, such as ion milling, is performed. The milling process includes milling the structure at high incidence and milling the structure at razing incidence. The milling process can be performed only once, or repeated multiple times. High incidence can be defined as about 65 to about 90 degrees from the plane of the surface being milled. Razing incidence can be defined as about 0 to about 30 degrees from the plane of the surface being milled.
    Type: Application
    Filed: August 29, 2003
    Publication date: March 3, 2005
    Inventors: Amanda Baer, Marie-Claire Cyrille, Frederick Dill, Wipul Jayasekara, Jui-Lung Li, Hugo Santini, Benjamin Wang
  • Patent number: 6833982
    Abstract: A magnetic tunnel junction (MTJ) sensor in which the free layer longitudinal biasing elements are coupled, without insulation, to the free layer outside of the MTJ stack to provide reliable non-shunting MTJ free layer stabilization without extremely thin dielectric layers. In one embodiment, hard magnetic (HM) layers are disposed in contact with the free layer outside of and separated from the MTJ stack active region by a thick dielectric layer. In another embodiment, antiferromagnetic (AFM) bias layers are disposed in contact with the free layer outside of and separated from the MTJ stack active region by a thick dielectric layer. In other embodiments, nonconductive HM layers are disposed either in contact with the free layer outside of the MTJ stack active region and/or in abutting contact with the MTJ stack active region.
    Type: Grant
    Filed: May 3, 2001
    Date of Patent: December 21, 2004
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: Wipul Jayasekara
  • Publication number: 20040090716
    Abstract: A magnetic tunnel junction (MTJ) sensor in which the free layer longitudinal biasing elements are coupled, without insulation, to the free layer outside of the MTJ stack to provide reliable non-shunting MTJ free layer stabilization without extremely thin dielectric layers. In one embodiment, hard magnetic (HM) layers are disposed in contact with the free layer outside of and separated from the MTJ stack active region by a thick dielectric layer. In another embodiment, antiferromagnetic (AFM) bias layers are disposed in contact with the free layer outside of and separated from the MTJ stack active region by a thick dielectric layer. In other embodiments, nonconductive HM layers are disposed either in contact with the free layer outside of the MTJ stack active region and/or in abutting contact with the MTJ stack active region.
    Type: Application
    Filed: June 30, 2003
    Publication date: May 13, 2004
    Applicant: Hitachi Global Storage Technologies
    Inventor: Wipul Jayasekara
  • Publication number: 20040017641
    Abstract: A magnetic tunnel junction (MTJ) sensor in which the free layer longitudinal biasing elements are coupled, without insulation, to the free layer outside of the MTJ stack to provide reliable non-shunting MTJ free layer stabilization without extremely thin dielectric layers. In one embodiment, hard magnetic (HM) layers are disposed in contact with the free layer outside of and separated from the MTJ stack active region by a thick dielectric layer. In another embodiment, antiferromagnetic (AFM) bias layers are disposed in contact with the free layer outside of and separated from the MTJ stack active region by a thick dielectric layer. In other embodiments, nonconductive HM layers are disposed either in contact with the free layer outside of the MTJ stack active region and/or in abutting contact with the MTJ stack active region.
    Type: Application
    Filed: July 16, 2003
    Publication date: January 29, 2004
    Applicant: Hitachi Global Storage Technologies
    Inventor: Wipul Jayasekara