Electrostatic Discharge (esd) Protection Patents (Class 360/323)
  • Patent number: 7864489
    Abstract: Provided is a thin-film magnetic head in which a noise due to the voltage potential difference between the read head element and the protective coat surface is suppressed. The thin-film magnetic head comprises: a read head element, one end surface of the read head element reaching an head end surface on the ABS side; a protective coat formed on the head end surface in such a way to cover at least the one end surface of the read head element; and at least one antistatic means for preventing the protective coat from being electrostatically charged, formed on/above the element formation surface, one end surface of the at least one antistatic means reaching the head end surface, the protective coat covering a portion, not the whole, of the one end surface of the at least one antistatic means on the head end surface.
    Type: Grant
    Filed: February 26, 2007
    Date of Patent: January 4, 2011
    Assignee: TDK Corporation
    Inventors: Kei Hirata, Takeo Kagami, Takumi Uesugi, Tetsuro Sasaki
  • Patent number: 7852591
    Abstract: A read head circuit comprises a read element including first and second terminals. A shunting device comprises a transistor including a first terminal that is connected to the first terminal of the read element, a second terminal that is connected to the second terminal of the read element, and a control terminal. The shunting device shorts the first and second terminals when the control terminal is not powered.
    Type: Grant
    Filed: December 21, 2006
    Date of Patent: December 14, 2010
    Assignee: Marvell International Ltd.
    Inventor: Pantas Sutardja
  • Patent number: 7827512
    Abstract: A plurality of internal circuits (11 to 14) are formed on a semiconductor chip 10, and receive different power supply voltages. An ESD protection circuit (15) is connected to the power supply lines (31 to 34) for the internal circuits (11 to 14). The area in which the protection circuit (15) is formed is closer to the center of the semiconductor chip (10) than the areas for the internal circuits (11 to 14). Surge voltages applied to the power supply pads reach the protection circuit before reaching the reaching the internal circuits.
    Type: Grant
    Filed: July 9, 2007
    Date of Patent: November 2, 2010
    Assignee: Oki Semiconductor Co., Ltd.
    Inventor: Fujiyuki Minesaki
  • Patent number: 7773349
    Abstract: In a CPP MR device such as a tunnel magnetoresistive (TMR) device, shoulders that have a magnetic moment that is matched to the magnetic moments of the free layer extend between the free layer and the S2 shield to provide an electrical path from one shoulder, through the shield, to the other shoulder for dissipating edge charges. Thus, a CPP MR device may include a seed stack, a pinned stack on the seed stack, and a tunnel barrier on the pinned stack. A free stack may be on the tunnel barrier, and the free stack can include a free sublayer separated from a magnetic shield and a path for dissipating edge charges in the free stack through the magnetic shield.
    Type: Grant
    Filed: February 10, 2006
    Date of Patent: August 10, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Robert Stanley Beach, Wipul Pemsiri Jayasekara, Vladimir Nikitin
  • Patent number: 7773347
    Abstract: A thin-film magnetic head has a plurality of MR read head elements. Each MR read head element includes shield layers electrically insulated from the ground. An electrical resistor layer is electrically connected between the shield layer of one of the plurality of MR read head elements and the shield layer of the other one of the plurality of MR read head elements.
    Type: Grant
    Filed: March 16, 2007
    Date of Patent: August 10, 2010
    Assignee: TDK Corporation
    Inventors: Kazuhiko Maejima, Hiroshi Kamiyama, Tomonaga Nishikawa
  • Patent number: 7768268
    Abstract: Test methods and components are disclosed for testing the quality of the ground connection fabrication process for ESD shunt resistors in magnetic heads. A wafer is populated with one or more test components along with magnetic heads. The test components are fabricated with ESD shunt resistor ground connections created by the same or similar process used to fabricate the ESD shunt resistor ground connections in magnetic heads on the wafer. The resistance of the test component ground connections may then be measured in order to determine the quality of the ground connections formed by the fabrication process. The quality of the ground connection fabrication process may then be determined based on the measured resistance of the test components.
    Type: Grant
    Filed: December 27, 2007
    Date of Patent: August 3, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Satoru Araki, Robert S. Beach, David J. Seagle
  • Patent number: 7715141
    Abstract: A magnetic data storage system according to one embodiment includes a head having a reader, the reader further comprising a shield, a sensor, and leads coupled to the sensor; a charge clamp circuit electrically coupling the shield to the leads; and a bias circuit for passing a bias current through the sensor via the leads; wherein the bias circuit maintains a potential of the shields at about a ground potential.
    Type: Grant
    Filed: March 9, 2007
    Date of Patent: May 11, 2010
    Assignee: International Business Machines Corporation
    Inventor: Robert Glenn Biskeborn
  • Patent number: 7707707
    Abstract: A method of temporarily protecting an electrically sensitive component from damage due to electrostatic discharge includes defining a shunt having first and second leads electrically connected in parallel with the component and separated by a gap. A portion of a shield layer is deposited to form the shunt between the first and second leads to span the gap therebetween and form a shunted assembly. The shunted assembly and component are lapped to form the ABS at the location of the component, a sacrificial carbon overcoat is deposited on the ABS, and additional processing is performed on the shunted assembly. A portion of the shunted assembly, the shunt, and portions of the sacrificial carbon overcoat are then removed to form an electrical open for an unshunted assembly having ABS features comprising an air bearing cavity/deep gap at a former location of the shunted assembly.
    Type: Grant
    Filed: December 19, 2006
    Date of Patent: May 4, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventor: David John Seagle
  • Patent number: 7706109
    Abstract: A slider includes a Tunneling Magneto-Resistive (TuMR) read sensor and a shunt resistor connected in parallel. The shunt resistor may be located in a read structure of the slider. The shunt resistor may reduce a total resistance of the read structure and any corresponding impedance mismatch between the read structure, a transmission line, and a preamplifier. The shunt resistor may be made of a material having a near zero thermal coefficient of resistivity (TCR) to test a quality of the TuMR read sensor. The TuMR read sensor may be deemed defective if its TCR deviates from a population average by a specific criterion. The TuMR read sensor may include a MgO tunneling barrier to improve signal strength. The TuMR read sensor may include a free layer that is able to be saturated with a perpendicular background field to calculate a more accurate TCR of the TuMR read sensor.
    Type: Grant
    Filed: October 17, 2006
    Date of Patent: April 27, 2010
    Assignee: Seagate Technology LLC
    Inventors: Mark Nichols, Bill Edward Higgins, Michael Mallary, Lydia Baril
  • Patent number: 7692897
    Abstract: A transducing head includes a substrate, a writer positioned upon the substrate, and a reader positioned adjacent the writer. The writer is in electrical contact with the substrate.
    Type: Grant
    Filed: March 14, 2008
    Date of Patent: April 6, 2010
    Assignee: Seagate Technology LLC
    Inventors: Harry S. Edelman, Bradley H. Miller, Eric L. Granstrom
  • Publication number: 20100073826
    Abstract: A method for manufacturing a magnetic head with an electrostatic discharge resistor for preventing electrostatic discharge damage to magnetic head. The electrostatic discharge resistor is formed by a processes that saves manufacturing time and cost by forming resistor in the same deposition and patterning steps used to form the magnetoresistive sensor. However, the resistor includes only a portion of the layers used to form the magnetoresistive sensor, thereby ensuring that the resistor will have sufficient resistivity.
    Type: Application
    Filed: September 24, 2008
    Publication date: March 25, 2010
    Inventors: Satoru Araki, David John Seagle
  • Patent number: 7595949
    Abstract: A method for preventing electrical overstress from interfering with a magnetic read-write device by identifying one or more characteristic functions of the device that characterize electrical overstress, generating a wave form representative of the electrical overstress by using the one or more characteristic functions and enabling the generated wave form to be combined with a read signal to counteract the electrical overstress. The method can be implemented with a crosstalk cancellation circuit that includes a coupler filter configured to receive signals from the write driver, a differentiator to differentiate the signal, a gain adjust coupled to the coupler filter configured to adjust gain on the received signal, a phase adjust configured to adjust the phase to match the crosstalk, and an inverter coupled to invert the matched signal to enable cancellation of the crosstalk.
    Type: Grant
    Filed: December 2, 2004
    Date of Patent: September 29, 2009
    Assignee: Maxtor Corporation
    Inventors: Albert J. Wallash, Ferruh Gocemen, Jason Wolfson
  • Publication number: 20090180216
    Abstract: A magnetoresistive transducer head assembly includes a reader element, a writer element and a high impedance shunt electrically connecting the reader element and the writer element. The high impedance shunt provides a high impedance conductive path for maintaining electrostatic charge equipotential between the reader element and the writer element.
    Type: Application
    Filed: January 16, 2008
    Publication date: July 16, 2009
    Applicant: International Business Machines Corporation
    Inventors: Peter J. Golcher, Icko E.T. Iben, Ho-Yiu Lam, Jose Luis Salenga
  • Patent number: 7561382
    Abstract: A mechanism for protecting an electronic component from electrostatic discharge (ESD) damage. The system includes a cable adapted for coupling to an electronic device, the cable having multiple traces therein adapted for electrical communication with components of the electronic device. The cable has a window therein positioned between opposite ends of the cable. Portions of the traces are exposed in the window. A protective member is insertable in the window of the cable, the protective member having a conductive portion engaging the traces of the cable when inserted in the window of the cable for creating a short between at least some of the traces.
    Type: Grant
    Filed: November 10, 2004
    Date of Patent: July 14, 2009
    Assignee: International Business Machines Corporation
    Inventor: Hoodin Hamidi
  • Publication number: 20090168262
    Abstract: Methods and structures for the fabrication of a thin film, longitudinal and perpendicular recording heads are disclosed. The heads comprise a plurality of embedded static dissipative layers that extend a few nanometers from the air bearing surface. These extended layers are first to contact the magnetic media surface and drain any electric charge buildup before a damaging discharge occurs with read or write head components. The embedded static dissipative layers are particularly useful for use in heads utilizing thermal fly height control systems, which tend to increase the probability of damaging electrical discharge through critical head components.
    Type: Application
    Filed: December 26, 2007
    Publication date: July 2, 2009
    Inventors: Albert John Wallash, Hong Zhu
  • Publication number: 20090154031
    Abstract: The present invention provides a electrostatic discharge protection device for protecting giant magnetoresistive devices in hard disk drive from being damaged by transient current generated as a result of electrostatic discharge. Embodiments of the invention include pair of surface mount diodes that are connected back-to-back and connected to the shunting pads of a head gimbal assembly in parallel to the giant magnetoresistive device protect the giant magnetoresistive device from transient current generated by the electrostatic discharge.
    Type: Application
    Filed: December 13, 2007
    Publication date: June 18, 2009
    Inventors: Napoleon B. Bumanlag, Roger F. Galinggana,, JR., LLoyd Henry LI, Ray Nicanor Tag-At
  • Patent number: 7545608
    Abstract: A current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) read head structure has the MR read head located between first and second shields (S1, S2) on a substrate with a shunt resistor R1 connecting S1 to the substrate and a shunt resistor R2 connecting S2 to the substrate, with R1 and R2 being approximately equal. Because R1 and R2 are close enough in value there is no significant interference pickup in the low frequency region. The shunt resistors can be formed from high-resistivity metal nitrides or cermets. The spacing between the substrate and S1 may be selected to make the capacitance between S1 and the substrate approximately equal to the capacitance between S2 and the substrate to substantially reduce interference pickup in the high frequency region.
    Type: Grant
    Filed: October 30, 2006
    Date of Patent: June 9, 2009
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Satoru Araki, John Contreras, Klaas Berend Klaassen, Ramona Marie Patterson, David John Seagle, Howard Gordon Zolla
  • Patent number: 7541648
    Abstract: An electrostatic discharge (ESD) protection circuit that includes a parallel connection of parasitic vertical and lateral bipolar junction transistors (BJTs) each with a floating base and a metal oxide semiconductor (MOS) field transistor with a floating body is disclosed. The three transistors may be connected in parallel between a bond (input or output) pad and a substantially fixed voltage level (e.g., a ground (or zero potential) or Vcc, depending on the transistor configuration) in a semiconductor electronic device so as to protect transistor gates or other circuit portions from damage from electrostatic voltages. The parasitic BJTs and the field transistor may be configured to remain cut off so long as an input voltage at the pad is between a negative V1 voltage (?V1) (V1>0) and a +V2 voltage (V2>Vcc), thereby allowing a greater input voltage swing without signal clamping. In one embodiment, the parasitic BJTs are PNP transistors and the field transistor is a PMOS transistor.
    Type: Grant
    Filed: January 21, 2005
    Date of Patent: June 2, 2009
    Assignee: Micron Technology, Inc.
    Inventor: Joohyun Jin
  • Patent number: 7538986
    Abstract: A protective device for protecting an electronic device, e.g., MR head, from ESD/EOS damage includes a cable having leads coupled to the electronic device and a first port providing access to the leads. A second port with one-to-one electrical connection to each lead in the cable provides a second electrical access to the all leads. A shorting device is coupled to one of the ports thereby creating a short between both the leads of the extension and the leads of the cable. The other port is available for coupling to an external device, e.g., tester or end device while the short provides ESD/EOS protection.
    Type: Grant
    Filed: November 10, 2004
    Date of Patent: May 26, 2009
    Assignee: International Business Machines Corporation
    Inventor: Icko E. (Tim) Iben
  • Publication number: 20090086382
    Abstract: A post manufacturing inventory system to improve disk drive inventory after manufacturing are disclosed. One embodiment provides a computer system having serial number scanning capabilities to scan manufactured disk drive during a post manufacturing inventory count to reconcile with a drive count during manufacturing. In addition, a count verifier is coupled to the scanning unit to enable the inventory control system to verify real-time information read from the disk drives during inventory with pre-stored information pertaining to each drive.
    Type: Application
    Filed: September 28, 2007
    Publication date: April 2, 2009
    Inventors: Napoleon B. Bumanlag, Roger F. Galinggana, JR., LLoyd Henry Li, Ray Nicanor Tag-At
  • Patent number: 7502207
    Abstract: An apparatus and method for providing electrostatic discharge protection for a disc drive read head. A pair of depletion mode MOSFETS, and a fuse associated with each are disposed between the read head output terminals. The MOSFETS are controlled to an “off” state for testing the preamplifier prior to assembly of the read head. After assembly of the head, a second pair of MOSFETS is gated to an “on” state to open the fuses and thus permit normal operation of the read head.
    Type: Grant
    Filed: April 5, 2005
    Date of Patent: March 10, 2009
    Assignee: Agere Systems Inc.
    Inventors: Jason A. Christianson, Michael John O'Brien, Cameron Carroll Rabe, Carl F. Elliott
  • Publication number: 20090059440
    Abstract: The disclosure is related to detecting an electrostatic charge at a data storage device. The electrostatic charge can be detected and a data integrity management process can be implemented. In a particular embodiment, a method includes monitoring an electronic device having a data storage medium for an electrostatic event. The method also includes selectively performing a data integrity management process on the data storage medium when the electrostatic event is detected.
    Type: Application
    Filed: August 29, 2007
    Publication date: March 5, 2009
    Applicant: Seagate Technology LLC
    Inventors: Hla Moe, James Lai Kein Chang, Yu Nang Zai, Pei Koh Lee, Lucas Kong Yaw Lee, Boon Liong Tan
  • Patent number: 7489482
    Abstract: In the case of magnetic head of magnetoresistance effect type whose breakdown voltage is as low as 0.3 V, it is impractical to ignore even a very small amount of static electricity that occurs during fabrication or use. In one embodiment, the desired magnetic head is produced by forming an SiO2 layer on a silicon slider, thereby forming an SOI substrate; forming on the SOI substrate circuits to protect a TMR element from overvoltage and a read-write circuit; forming field effect transistors from an Si semiconductor layer (formed by reduction of the SiO2 layer or epitaxial growth on the SiO2 layer); forming three electrodes (source, gate, drain) on the Si semiconductor layer; forming a Schottky diode by Schottky contact (metal) with the Si semiconductor layer; forming overvoltage protective circuits of aluminum wiring on the SOI substrate; and forming a TMR element.
    Type: Grant
    Filed: December 10, 2004
    Date of Patent: February 10, 2009
    Assignee: Hitachi GLobal Storage Technologies Netherlands B.V.
    Inventors: Hiroyuki Ono, Hiroaki Suzuki, Toshio Sunaga, Hisatada Miyatake, Hideo Asano
  • Patent number: 7486475
    Abstract: A magnetic data system according to one embodiment includes at least one reader formed above a substrate, the at least one reader further comprising a shield and a magnetoresistive (MR) sensor. A first circuit sets a voltage (Vsub) of the substrate to about a voltage (Vshield) of the shield of the at least one reader.
    Type: Grant
    Filed: December 14, 2005
    Date of Patent: February 3, 2009
    Assignee: International Business Machines Corporation
    Inventor: Robert Glenn Biskeborn
  • Patent number: 7486476
    Abstract: A magnetic data system according to one embodiment includes a head having a plurality of readers formed above a common substrate, each reader further comprising a shield and a sensor, a bias circuit associated with each reader for passing a bias current through the sensor thereof, wherein the bias circuits are floating. A charge clamp electrically couples each shield to the associated bias circuit. A shield biasing circuit is operatively coupled to each shield for setting a potential of the shield independently of the bias current.
    Type: Grant
    Filed: December 14, 2005
    Date of Patent: February 3, 2009
    Assignee: International Business Machines Corporation
    Inventor: Robert Glenn Biskeborn
  • Patent number: 7480121
    Abstract: A magnetic storage system comprises a read element and an electrostatic discharge (ESD) protection circuit that communicates with the read element and that includes a normally-on transistor that shorts the read element when the magnetic storage system is unpowered.
    Type: Grant
    Filed: October 23, 2007
    Date of Patent: January 20, 2009
    Assignee: Marvell International Ltd.
    Inventor: Pantas Sutardja
  • Patent number: 7474513
    Abstract: A magneto-resistive (MR) transducer is capable of reading data signals magnetically recorded on a tape. The transducer includes a head-tape interface (HTI) and a MR sensor adjacent to the HTI. An electro-static discharge (ESD) element is coupled to the MR sensor, which is adapted to provide an electrical path from the MR sensor to a lower potential structure.
    Type: Grant
    Filed: June 29, 2005
    Date of Patent: January 6, 2009
    Assignee: Storage Technology Corp.
    Inventors: John P. Nibarger, Richard H. Dee
  • Patent number: 7469466
    Abstract: A method of temporarily protecting an electrically sensitive component from damage due to electrostatic discharge is disclosed. The method includes the steps of defining a first shield that forms a first lead for both a component and a shunt; depositing a conductive material on the first shield to form the component and the shunt; defining an edge of the component and an edge of the shunt together in a single masking step; refilling with insulation adjacent the component and the shunt to their respective edges on the first shield; defining a second shield on both the component and the shunt that forms a second lead for both the component and the shunt to form a shunted assembly that electrically protects the component; lapping the shunted assembly; and removing a portion of the shunted assembly to remove the shunt and form an electrical open for an unshunted assembly.
    Type: Grant
    Filed: January 4, 2005
    Date of Patent: December 30, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands BV
    Inventors: Robert Stanley Beach, David John Seagle, Jila Tabib
  • Publication number: 20080310055
    Abstract: The present invention provides methods and systems for repeatably creating and severing a short circuit to protect an electronic component from ESD. A short circuit may be formed between read sensor pads of a read sensor by depositing a shorting material on a magnetic head using a Laser Induced Forward Transfer (LIFT) process. The short circuit may be unshorted using a laser scan configured to sever the shorting material. In one embodiment, a shorting station may be provided to prevent spreading of the shorting material to undesired areas of the electronic component.
    Type: Application
    Filed: June 15, 2007
    Publication date: December 18, 2008
    Inventors: Robert E. Fontana, JR., Sergey Kiselev, Edward Hin Pong Lee, Kenneth Donald Mackay, Surya Narayan Pattanaik, Chie Ching Poon
  • Publication number: 20080273278
    Abstract: A protective device for protecting an electronic device, e.g., MR head, from ESD/EOS damage includes a cable having leads coupled to the electronic device and a first port providing access to the leads. A second port with one-to-one electrical connection to each lead in the cable provides a second electrical access to the all leads. A shorting device is coupled to one of the ports thereby creating a short between both the leads of the extension and the leads of the cable. The other port is available for coupling to an external device, e.g., tester or end device while the short provides ESD/EOS protection.
    Type: Application
    Filed: July 18, 2008
    Publication date: November 6, 2008
    Inventor: Icko E. (Tim) Iben
  • Publication number: 20080259506
    Abstract: A slider mounted CPP GMR or TMR read head sensor is protected from electrostatic discharge (ESD) damage and from noise and cross-talk from an adjacent write head by means of a balanced resistive/capacitative shunt. The shunt includes highly resistive interconnections between upper and lower shields of the read head and a grounded slider substrate and a low resistance interconnection between the lower pole piece of the write head and the substrate. The capacitances between the pole piece and the upper shield, the upper shield and the lower shield and the lower shield and the substrate are made equal by either forming the shields and pole piece with equal surface areas and separating them with dielectrics of equal thicknesses, or by keeping the ratio of area to insulator thicknesses equal.
    Type: Application
    Filed: June 19, 2008
    Publication date: October 23, 2008
    Inventors: Eric Cheuk Wing Leung, Anthony Wai Yuen Lai, Pak Kin Wong, David Hu, Moris Dovek, Rod Lee
  • Patent number: 7436630
    Abstract: A data storage device head having reduced media induced micro-discharge events. The data storage device head includes a support structure, and a wafer. A mitigation voltage, other than a ground potential, is presented to the wafer at a level sufficient to suppress media induced micro-discharge events.
    Type: Grant
    Filed: September 24, 2004
    Date of Patent: October 14, 2008
    Assignee: Storage Technology Corporation
    Inventors: Mark Lee Watson, Kevin Dale McKinstry, Jeffrey Glenn Villiard
  • Publication number: 20080204938
    Abstract: Provided is a thin-film magnetic head in which a noise due to the voltage potential difference between the read head element and the protective coat surface is suppressed. The thin-film magnetic head comprises: a read head element, one end surface of the read head element reaching an head end surface on the ABS side; a protective coat formed on the head end surface in such a way to cover at least the one end surface of the read head element; and at least one antistatic means for preventing the protective coat from being electrostatically charged, formed on/above the element formation surface, one end surface of the at least one antistatic means reaching the head end surface, the protective coat covering a portion, not the whole, of the one end surface of the at least one antistatic means on the head end surface.
    Type: Application
    Filed: February 26, 2007
    Publication date: August 28, 2008
    Applicant: TDK Corporation
    Inventors: Kei Hirata, Takeo Kagami, Takumi Uesugi, Tetsuro Sasaki
  • Patent number: 7402759
    Abstract: An insulating substrate includes a first area where a semiconductor device is disposed, a second area where a wiring electrically connecting to the semiconductor device is disposed, and a third area where a terminal electrically connecting to the wiring is disposed. A first wiring is disposed on a main surface of the insulating substrate in the second area and connects to the second wiring disposed in the first area and the terminal disposed in the third area through first and second interlayer connecting portions. With this configuration, the second wiring need not be disposed in the second area, so that flexibility in the second area used as a connecting portion increases.
    Type: Grant
    Filed: May 6, 2005
    Date of Patent: July 22, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Daigo Suzuki
  • Patent number: 7400474
    Abstract: A magnetic tape head having an array of reader/writer pairs formed on a common substrate, each reader/writer pair being configured in a piggyback configuration such that the writer and reader of each pair are aligned in a direction parallel to a relative direction of media travel thereover. Each reader comprises a first shield, a second shield, a sensor positioned between the shields, and leads coupled to the sensor. Each writer comprises a first pole and a second pole. A charge clamp circuit electrically couples at least one of the reader shields to at least one of the leads. An electrical conductor operatively electrically couples the at least one of the shields to at least one of the poles.
    Type: Grant
    Filed: October 28, 2005
    Date of Patent: July 15, 2008
    Assignee: International Business Machines Corporation
    Inventors: Robert Glenn Biskeborn, Peter VanderSalm Koeppe
  • Patent number: 7397636
    Abstract: A method for preventing electrostatic discharge (ESD) damage in the head-suspension assembly (HSA) construction process. The method uses a novel GMR magnetic recording head on a conductive slider substrate, the GMR head being electrically connected to the substrate and its conducting leads having balanced resistances between the leads and the substrate. By establishing an electrical connection between the GMR head and the slider substrate, the entire HSA can be grounded during its construction. By also grounding any nearby conducting elements that could inadvertently contact the HSA or its parts, no accumulated tribocharges can discharge through the sensitive GMR sensor element.
    Type: Grant
    Filed: March 12, 2007
    Date of Patent: July 8, 2008
    Assignee: Headway Technologies, Inc.
    Inventor: Li-Yan Zhu
  • Patent number: 7392579
    Abstract: A slider mounted CPP GMR or TMR read head sensor is protected from electrostatic discharge (ESD) damage and from noise and cross-talk from an adjacent write head by means of a balanced resistive/capacitative shunt. The shunt includes highly resistive interconnections between upper and lower shields of the read head and a grounded slider substrate and a low resistance interconnection between the lower pole piece of the write head and the substrate. The capacitances between the pole piece and the upper shield, the upper shield and the lower shield and the lower shield and the substrate are made equal by either forming the shields and pole piece with equal surface areas and separating them with dielectrics of equal thicknesses, or by keeping the ratio of area to insulator thicknesses equal.
    Type: Grant
    Filed: March 7, 2005
    Date of Patent: July 1, 2008
    Assignees: Headway Technologies, Inc., SAE Magnetics (HK) Ltd.
    Inventors: Eric Cheuk Wing Leung, Anthony Wai Yuen Lai, Pak Kin Wong, David Hu, Moris Dovek, Rod Lee
  • Patent number: 7375931
    Abstract: Recording heads having an ESD shunt trace and methods of fabricating the same are disclosed. A recording head of the invention includes a first shield, a second shield, an MR read element between the first shield and the second shield, and an ESD shunt trace. The ESD shunt trace is formed from MR layers and is connected to the MR read element and one or both of the first shield and the second shield. One or more of the MR layers forming the ESD shunt trace are processed to reduce the MR properties of the ESD shunt trace. Examples of processing the ESD shunt trace are ion milling, ion implantation, oxidizing, reactive ion etching, sputter etching, wet chemical etching, etc.
    Type: Grant
    Filed: September 30, 2005
    Date of Patent: May 20, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands, B.V.
    Inventors: Wipul P. Jayasekara, Howard G. Zolla
  • Patent number: 7369364
    Abstract: An interconnect that may reduce a head slider's exposure to electrostatic discharge events and may dissipate charging of the head is provided. Conductive and nonconductive adhesives are used to adhere a head slider to the interconnect. An electromagnetic interference generating circuit generates current that flows through the conductive adhesive bonding the head slider to the flexure arm. The electromagnetic interference current breaks down the resistance of the conductive adhesive to dissipate an electrostatic voltage charge on the head slider. This may prolong the life of the head slider and a read/write head coupled to the head slider.
    Type: Grant
    Filed: December 19, 2003
    Date of Patent: May 6, 2008
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Eunkyu Jang, Hyung Jal Lee
  • Patent number: 7369370
    Abstract: A method for preventing electrostatic discharge (ESD) damage in the head-suspension assembly (HSA) construction process. The method includes the use of a novel GMR magnetic recording head on a conductive slider substrate, the GMR head being electrically connected to the substrate and its conducting leads having balanced resistances between the leads and the substrate. By establishing an electrical connection between the GMR head and the slider substrate, the entire HSA can be grounded during its construction. By also grounding any nearby conducting elements that could inadvertently contact the HSA or its parts, no accumulated tribocharges can discharge through the sensitive GMR sensor element.
    Type: Grant
    Filed: March 12, 2007
    Date of Patent: May 6, 2008
    Assignee: Headway Technologies, Inc.
    Inventor: Li-Yan Zhu
  • Patent number: 7355821
    Abstract: Disclosed is an MR head in which the MR element resists damage due to ESD. A magneto resistive head to be in contact with a running magnetic tape includes a substrate, an insulating layer, a magneto resistive element located in the insulating layer, at least one shield layer for shielding the magneto resistive element from magnetic fields, and a conductive layer that has a conductive surface being in contact with the magnetic tape and that is electrically connected to the substrate. In this head, static electricity accumulated on the magnetic tap is discharged through the conductive layer and the substrate.
    Type: Grant
    Filed: February 9, 2005
    Date of Patent: April 8, 2008
    Assignee: FUJIFILM Corporation
    Inventor: Takashi Suda
  • Patent number: 7345853
    Abstract: A device according to one embodiment includes an electronic component such as an MR sensor, a pair of leads operatively coupled to the electronic component, and shorting material between the leads, the shorting material having been applied by a laser deposition process, the shorting material having been severed. A magnetic storage system according to another embodiment includes magnetic media; and at least one head for reading from and writing to the magnetic media, each head having: a sensor; and a writer coupled to the sensor. The system also includes a pair of pads or leads operatively coupled to the head; shorting material between the leads, the shorting material having been applied by a laser deposition process, the shorting material having been severed; a slider for supporting the head; and a control unit coupled to the head for controlling operation of the head.
    Type: Grant
    Filed: May 8, 2007
    Date of Patent: March 18, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B. V.
    Inventors: Meng Ding, Surya Narayan Pattanaik, Chie Ching Poon, Neil Leslie Robertson
  • Publication number: 20080055788
    Abstract: This invention provides a magnetic head having adjustable input/output impedance, and also provides a manufacturing method of the same, a head suspension assembly and a magnetic storage device. The magnetic head has a perpendicularly feeding type magnetoresistive element, a pair of electrodes, a pair of first conductive wires for electrically connecting the pair of electrodes to a detecting circuit device, a pair of second conductive wires for discharging static electricity by electrically connecting the pair of the first conductive wires and a grounded substrate through bleed resistance, and one or more grounded electrically shielded layers between the first conductive wires and the substrate, and/or between the second conductive wires and the substrate.
    Type: Application
    Filed: March 1, 2007
    Publication date: March 6, 2008
    Inventor: Hirofumi Nagai
  • Publication number: 20080037182
    Abstract: A structure for preventing Electrostatic Discharge (ESD) damage to a magnetoresistive sensor during manufacture. The structure includes a switching element that can be switched off during testing of the sensor and then switched back on to provide ESD shunting to the sensor. The switch can be a thermally activated mechanical relay built onto the slider. The switch could also be a programmable resistor that includes a solid electrolyte sandwiched between first and second electrodes. One of the electrodes functions as an anode. When voltage is applied in a first direction an ion bridge forms across through the electrolyte across electrodes making the resistor conductive. When a voltage is applied in a second direction, the ion bridge recedes and the programmable resistor becomes essentially non-conductive.
    Type: Application
    Filed: June 27, 2006
    Publication date: February 14, 2008
    Inventors: Thomas Robert Albrecht, Robert E. Fontana, Bruce Alvin Gurney, Timothy Clark Reiley, Xiao Z. Wu
  • Patent number: 7301732
    Abstract: A method for preventing electrostatic discharge (ESD) damage in the head-suspension assembly (HSA) construction process. The method includes the use of a novel GMR magnetic recording head on a conductive slider substrate, the GMR head being electrically connected to the substrate and its conducting leads having balanced resistances between the leads and the substrate. By establishing an electrical connection between the GMR head and the slider substrate, the entire HSA can be grounded during its construction. By also grounding any nearby conducting elements that could inadvertently contact the HSA or its parts, no accumulated tribocharges can discharge through the sensitive GMR sensor element.
    Type: Grant
    Filed: March 12, 2007
    Date of Patent: November 27, 2007
    Assignee: Headway Technologies, Inc.
    Inventor: Li-Yan Zhu
  • Patent number: 7296336
    Abstract: A simple method is provided for protecting slider mounted read/write transducers from electrostatic discharge damage during the manufacture of disk drives. The method involves placing a ball of conducting thermoplastic resin, such as a gold or silver epoxy, between the terminal pads of the transducer and using the ball to shunt the pads to read-head shields and the slider substrate and thence to ground. The epoxy ball is easily applied and easily removed and can be used at different stages in the manufacturing process.
    Type: Grant
    Filed: May 25, 2004
    Date of Patent: November 20, 2007
    Assignee: SAE Magnetics (H.K.) Ltd.
    Inventors: Niraj Mahadev, Kazumasa Yasuda, Rudy Ayala
  • Patent number: 7291279
    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: Grant
    Filed: April 30, 2004
    Date of Patent: November 6, 2007
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Frederick Hayes Dill, Meng Ding, Kuok San Ho, Jordan Asher Katine, Scott Arthur MacDonald, Huey-Ming Tzeng
  • Patent number: 7289302
    Abstract: A slider for use in a magnetic disk drive includes read pads for connecting to a flexible circuit that couples to a pre-amplifier circuit, a transducer, and a protector connected to the transducer and the read pads to protect the transducer against damage from electrostatic discharge (ESD). Examples of transducers that may be used include a giant magnetoresistive (GMR) sensor and a tunneling magnetoresistive (TMR) sensor.
    Type: Grant
    Filed: September 24, 2002
    Date of Patent: October 30, 2007
    Assignee: Maxtor Corporation
    Inventor: Michael Mallary
  • Patent number: 7286328
    Abstract: A magnetic storage system comprises a read element and an electrostatic discharge (ESD) protection circuit that includes a shunting device including a first terminal that communicates with a first terminal of the read element and a second terminal that communicates with a second terminal of the read element. The shunting device is conductive when the read element is disabled and nonconductive when the read element is enabled.
    Type: Grant
    Filed: February 27, 2004
    Date of Patent: October 23, 2007
    Assignee: Marvell International Ltd.
    Inventor: Pantas Sutardja
  • Patent number: 7256970
    Abstract: A magnetic reading head comprising: a bottom shield; a top shield; an AMR device with MR and SAL separated by a thin insulating layer; a first insulting gap layer between said bottom shield and said AMR; a second insulating gap layer between said AMR and said top shield; a conductive layer contact at one end region of said MR and SAL. Furthermore, magnetic reading heads with GMR device free of electric-pop noise also are disclosed.
    Type: Grant
    Filed: December 12, 2002
    Date of Patent: August 14, 2007
    Assignee: SAE Magnetics (HK) Ltd.
    Inventors: Yong Shen, Kwok Kam Leung, Hiroshi Kiyono, Tetsuo Miyazaki