Abstract: Methods and apparatus for selecting a cellular network to provide one or more communication services for a mobile communication device are disclosed. A scanning operation is performed by the mobile device to identify a plurality of cellular networks that support a voice communication service in a geographic coverage area. The mobile device then identifies which of the cellular networks makes a data communication service available to it. Advantageously, the mobile device assigns priority to or selects a cellular network that makes the data communication service available over a network that fails to make the data communication service available, and may register with that network. The data communication service may include, as examples, an e-mail communication service or an Internet access service. Preferably, the cellular network operates in accordance with GSM (Global System for Mobile) and GPRS (Generalized Packet Radio Service).

Abstract: An apparatus and method of lapping of rows of magnetic recording heads uses multiple fluid-filled ports with variable pressure against a flexible adhesive tape to secure to and support the row. The tape provides the necessary tangential restraining force to drag the workpiece along a lapping plate. The multiple ports beneath the tape provide the necessary normal force to press the workpiece against the lapping plate to allow lapping to occur. The amount of material removal from the row is varied by adjusting the pressure in the ports such that higher pressure is applied to those heads with higher stripe height, and lower pressure is applied to recording heads with lower stripe height. To set or adjust the port pressures, measurements of the read sensor resistance are taken to calculate the stripe height. The stripe height is roughly proportional to the reciprocal of resistance.

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.

Abstract: An apparatus and method of lapping of rows of magnetic recording heads uses multiple fluid-filled ports with variable pressure against a flexible adhesive tape to secure to and support the row. The tape provides the necessary tangential restraining force to drag the workpiece along a lapping plate. The multiple ports beneath the tape provide the necessary normal force to press the workpiece against the lapping plate to allow lapping to occur. The amount of material removal from the row is varied by adjusting the pressure in the ports such that higher pressure is applied to those heads with higher stripe height, and lower pressure is applied to recording heads with lower stripe height. To set or adjust the port. pressures, measurements of the read sensor resistance are taken to calculate the stripe height. The stripe height is roughly proportional to the reciprocal of resistance.

Abstract: A magneto-resistive device with built-in test structure. The magneto-resistive device includes a slider having first and second lower termination pads and first and second upper termination pads. A first conductive trace element electrically couples the first lower termination pad to the first upper termination pad and a second conductive trace element electrically couples the second lower termination pad to said second upper termination pad. The magneto-resistive device also includes a magneto-resistive transducer deposited on the slider and the resistance of the magneto-resistive transducer is obtained by passing an electrical current between the first and second lower termination pads and measuring a voltage across the first and second upper termination pads.

Abstract: An in-situ (result-directed/predictive) MR stripe height calibration method capable of operating on the fly during lapping operation. The method involves utilization of an interval sampling technique, which provides a high number of data points. The data provided are filtered and averaged at each kerf location to provide a much higher calibration accuracy than previously available. The primary advantage is to create an accurate relationship between MR element resistance and its stripe height while the MR element is being lapped. The method thus provides the ability to target either resistance or stripe height or a combination of both during the lapping process. Finally, the system is completely self-contained and does not required wafer data.

Abstract: A magneto-resistive device with built-in test structure. The magneto-resistive device includes a slider having first and second lower termination pads and first and second upper termination pads. A first conductive trace element electrically couples the first lower termination pad to the first upper termination pad and a second conductive trace element electrically couples the second lower termination pad to said second upper termination pad. The magneto-resistive device also includes a magneto-resistive transducer deposited on the slider and the resistance of the magneto-resistive transducer is obtained by passing an electrical current between the first and second lower termination pads and measuring a voltage across the first and second upper termination pads.

Abstract: An in-situ (result-directed/predictive) MR stripe height calibration method capable of operating on the fly during lapping operation. The method involves utilization of an interval sampling technique, which provides a high number of data points. The data provided are filtered and averaged at each kerf location to provide a much higher calibration accuracy than previously available. The primary advantage is to create an accurate relationship between MR element resistance and its stripe height while the M element is being lapped. The method thus provides the ability to target either resistance or stripe height or a combination of both during the lapping process. Finally, the system is completely self-contained and does not required wafer data.

Abstract: A dual element electrical lapping guide system is disclosed for a row of multi-layer dual element magnetoresistive and inductive magnetic transducers formed on a substrate, which will be used to form sliders, the sliders being separated by separation kerfs, and the multi-layer transducers aligned along an edge of the substrate for lapping of the edge. The dual element lapping guide system comprises superposed resistive elements and electrical switch elements, each positioned in one of the separation kerfs, and having an edge thereof positioned so as to be aligned with the edge of the row and subject to lapping of the row. Each electrical switch element comprises a bottom and a top layer connected at one end thereof and separated at the other end thereof by an insulation layer, so as to be initially closed at the connected end, which end is aligned with the edge of the multi-layer transducers and subject to lapping of the row at the connected end to open the switch element.

Abstract: Disclosed is an apparatus and method for calibrating the deposition windage of deposited thin film resistive elements, such as magnetoresistive read elements for magnetic heads which are to be lapped, comprising one set of at least three resistive elements having different nominal height dimensions, a resistance detector for measuring the resistance of each of the resistive elements, and a windage calculator responsive to the nominal height dimensions and to the measured resistances of each of the resistive elements for calculating the windage of the one set of resistive elements.

Abstract: A lapping method and device for lapping magnetic heads to provide an air bearing surface with improved surface quality including increased smoothness, reduced rolloff, and reduced recession. The lapping machine includes a lapping plate having a grinding surface, a linear motion mechanism for moving the ABS over the grinding surface in a first, linear direction, and a micro-advance mechanism for controllably advancing the workpiece over the grinding surface in a second direction that is preferably perpendicular. The lapping method comprises affixing the unfinished magnetic head proximate to the lapping plate and depositing an abrasive slurry on the grinding surface. An initial rough lapping stage is performed, including moving the grinding surface so that the workpiece is lapped to a first predetermined target specification.

Abstract: A lapping control system for accurately obtaining a desired throat height of each of a plurality of batch fabricated thin film magnetic transducers, comprises a row of thin film transducers formed on a substrate, the row comprising a height defining edge and at least four spaced sensing devices, a first two of the sensing devices comprising switch devices each offset a predetermined amount from the height defining edge, and a second two of the sensing devices comprising resistive devices each offset a predetermined amount from the height defining edge, a support of mounting the row of thin film magnetic transducers in a position to lap the height defining edge of each of the thin film magnetic transducers and the sensing devices, a measuring device for measuring the resistance of the resistive devices during lapping of the height defining edge, apparatus responsive to the measured resistance and to a selected state of at least one of the two switch devices for calibrating resistance versus throat height chara

Abstract: A novel thin film magnetic head fabrication process is provided for fabricating a plurality of thin film magnetic head elements. The process begins with the selection of an appropriate wafer substrate of suitable size and quality. At least two primary sub-areas of the wafer substrate are designated as work areas for the deposition of magnetic recording transducer elements. The work areas have first and second end portions and are arranged in mutually adjacent relation along a shared boundary zone that extends in a first direction through the wafer substrate between the first and second end portions. The wafer substrate is populated with plural rows of magnetic recording transducer elements in the designated work areas such that the plural rows extend in a second direction that is substantially perpendicular to the first direction. The work areas are separated from the wafer substrate and magnetic transducer slider elements are fabricated from the plural rows of magnetic recording transducer elements.

Abstract: A lapping control system for accurately obtaining a desired throat height of each of a plurality of batch fabricated thin film magnetic transducers, comprises a row of thin film transducers formed on a substrate, the row comprising a height defining edge and at least four spaced sensing devices, a first two of the sensing devices comprising switch devices each offset a predetermined amount from the height defining edge, and a second two of the sensing devices comprising resistive devices each offset a predetermined amount from the height defining edge, a support of mounting the row of thin film magnetic transducers in a position to lap the height defining edge of each of the thin film magnetic transducers and the sensing devices, a measuring device for measuring the resistance of the resistive devices during lapping of the height defining edge, apparatus responsive to the measured resistance and To a selected sate of at least one of the two switch devices for calibrating resistance versus throat height charac

Abstract: A lapping control system for a row of thin film magnetic transducers formed on a substrate. Each of the magnetic transducers comprises a magnetoresistive (MR) element, and the row is supported on a holder which has an elongated H-shaped slot near one edge to form a beam member upon which the row is mounted. The beam member is capable of being deflected in a substantially quadratic curvature when subjected to pressure from a pressure transducer at the middle of the beam member. The resistance of each of the MR elements is measured during lapping, and a control signal is generated to control the pressure transducers to control lapping with proper BALANCE and BOW and to terminate lapping when the desired MR element height is reached.

Abstract: A lapping control system for a row of thin film magnetic transducers formed on a substrate. Each of the rows comprises a plurality of thin film magnetic transducers and at least two test structures. Each test structure has at least two elements which comprises some combination of switch elements or test thin film magnetic transducers. As the row of transducers is lapped, each time one of the switch elements is opened, the saturation current (ISAT) of one or more of the thin film magnetic transducers is measured and recorded so that a correlation between ISAT and throat height of the transducers is established during lapping. This correlation is used to establish the point at which lapping should be terminated.

Abstract: A method for determining the position of a lapped edge of a substrate during lapping of a row of thin film magnetic transducer elements. First and second electrical lapping guide structures are formed on each side of the row of transducer elements. The lapping guide structures include a series of switching junctions, each switching junction paralleled by a resistor. A lapping resistor which provides a change in resistance proportional to the lapping of the row is measured and compared with the position of the lapping plane as determined from each switching junction change of state. Calibration of the resistor versus lapping plane position is effected to permit an accurate determination of the lapped surface from subsequent resistance measurements of the lapping resistor.

Abstract: An electrical lapping guide resistor for measuring the lapping distance in a process for manufacturing thin film magnetic transducers. Final throat height is measured with an electrical lapping guide resistor which provides a linear change in resistance versus lapping distance. The lapping guide resistor is configured in a shape such that the effective length of the resistors increases as the effective width decreases. In a preferred embodiment of the invention, the resistor includes first and second converging edges which extend from a rearward edge parallel to the final throat height toward the lapping surface. Conductors are disposed along the converging edges. Measurements of the change in lapping distance are effected by measuring the distance between the conductors.

Abstract: A method for making a thin film magnetic head assembly comprising the steps of depositing a first magnetic pole piece layer, depositing a nonmagnetic material gap forming layer, and depositing a protective layer of etch resistant material. A layer of insulation is deposited upon which is formed a conductive coil. A leveling pad of insulation is deposited over the conductive coil, and the part of the protective layer which is not covered by the insulation is removed. The gap forming layer is therefore protected during the processing steps so that a desired gap length is produced. The second magnetic pole piece layer is then deposited to complete the magnetic circuit.

Abstract: An integrated read/write head assembly incorporates a thin film inductive write head subassembly comprising first and second pole pieces that define a write transducing gap, and a magnetoresistive read subassembly disposed in the write gap. The first write pole piece is extended so as to provide a planar conductive path from the terminal connections or studs to the magnetoresistive read subassembly, thereby forming a uniform surface for deposition of the magnetoresistive read subassembly.