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.
Abstract:
A method and apparatus for controlling a multiple-stage actuator for a disk drive which does not require an additional sensor for measuring the relative position between adjacent actuator stages. In a two-stage actuator system, a position-type secondary actuator (SA) rides piggyback on a primary actuator (PA). The repeatable runout is measured and used as a feedforward signal to the PA. If the PA is a rotary actuator, the feedforward signal is preferably arc corrected for the arc that the head transverses from the inner radius to the outer radius of the disk. Added to the feedforward signal is the moving average of the drive signal applied to the SA. Because the SA is of the position-type having a neutral position, this moving average is proportional to the time cumulative drift present in the two-stage actuator system, and forces the PA in a direction that minimizes deviation of the SA from its neutral position. This minimizes the range requirement for the SA, the main purpose of which is to reduce non-repeatable runout.
Abstract:
A microfabricated wobble motor with a positioning arm attached to the wobble motor rotor acts as a fine positioner with bidirectional movement. The primary application is a rotary actuator for the read/write head in a very small magnetic recording disk drive. An integrated head-arm assembly is attached at one end to the rotor of the wobble motor. The other end of the head-arm assembly has a head carrier that is maintained in contact with the disk. Head position error information is read from the disk and used to provide control signals to each of the stator elements. The stator elements are sequentially addressed by applying a voltage from a driver circuit. This causes the rotor to be electrostatically attracted to the activated stators, so that the rotor is movable bidirectionally. The read/write head can thus be moved bidirectionally to any of the data tracks on the disk and maintained on a desired data track for reading or writing data. The fine positioner also includes a digital control system where each of the stator elements is represented by an address, and the movement of the rotor is controlled by incrementing or decrementing the stator address in an address register.
Abstract:
An ohmic contact for a silicon slider body is disclosed. A scanned laser beam locally heats a metal film on the slider body to interdiffuse the metal and silicon while minimizing the total thermal load on the slider body. This localized heating avoids thermal damage to the sensitive magnetic head region on the slider. The native oxide layer on the slider is removed by a sputter etch, followed by deposition of a diffusion layer. A capping layer is then deposited to reduce oxidation during subsequent processing. The metal layer is then locally annealed by scanning the laser beam over the target area. Contact resistance of less than 100 ohms is achieved while minimizing the thermal load on the slider body.
Abstract:
An electrical lapping guide is disclosed which is suitable for use with a single slider having a magnetic recording head. The electrical lapping guide provides for monitoring the progression of lapping; does not require additional electrical connection pads; and, is removable after completion of lapping.
Abstract:
A bistable micromechanical switch that includes a substrate, at least two anchor points formed on the substrate, and a beam structure that includes a two-material beam attached to at least two anchor points. The two-material beam has a first portion, a second portion and a center portion. The first portion of the two-material beam is formed from a first layer of a first material and a second layer of a second material such that the first layer of the first portion is proximate to the surface of the substrate and the second layer of the first portion is remote from the surface of the substrate. The first material has a first coefficient of thermal expansion and the second material has a second coefficient of thermal expansion such that the second coefficient of thermal expansion is greater than the first coefficient of thermal expansion. The second portion of the two-material beam is formed from a first layer of the second material and a second layer of the first material such that the first layer of the second portion is proximate to the surface of the substrate and the second layer of the second portion is remote from the surface of the substrate. The beam structure has a first and a second stable state such that the center portion of the beam structure is deflected toward the surface of the substrate for the first stable state and is deflected away from the surface of the substrate for the second stable state.
Abstract:
A slider for use in a magnetic data recording system that is constructed from a Si wafer by a method that saves valuable wafer real estate by minimizing kerf related to the cutting of the wafer into slider rows. The sliders are produced from a (110) oriented Si wafer, and the sliders are parsed into rows by a process that involves forming a mask having a trench or opening between the rows of sliders at the location of the desired cut and parallel to a vertical (111) plane of the wafer. The wafer is then exposed to KOH which removes wafer material in the vertical direction through the wafer without removing wafer material in the horizontal direction. The vertical removal of wafer material is due to the extreme preferential removal of the (110) surface Si over that of the (111) surface Si. This results in a narrow straight trench being formed. The KOH etch removal can form a trench or cut having a width of only 30 to 50 um through a 1 mm thick wafer.
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. Another possible programmable resistor uses a phase change material that can change between an amorphous high resistance state and a crystalline low resistance state upon the application of a certain heat treatments.
Abstract:
At least one modified strain region having a damage depth between 0.1 and 2 microns in a disk drive slider is created by implantation with ions, electrons or neutral atoms. The modified strain region induces a deformation of the disk drive slider. The nature and extent of this deformation is determined by the interaction between the slider and the modified strain region.
Abstract:
A rotary microactuator includes a stationary structure formed on a substrate, a movable structure, and at least a pair of wires connected to the movable structure that conduct a signal associated with the movable structure. Each wire of the pair of wires has a first end that is connected in a cantilever manner to the substrate and a second end that is connected to the movable structure. The wires each have a serpentine shape between the first end and the second end, a predetermined spring stiffness, and a predetermined electrical characteristic. The microactuator also includes a magnetic head slider that is attached to the movable structure, and at least another pair of wires conducting a signal associated with a magnetic head of the slider. Each of the another pair of wires has a first end that is connected in a cantilever manner to the substrate and a second end that is connected to the movable structure. Like the first pair of wires, each of the another pair of wires has a serpentine shape between the first end and the second end of the wire. Electronic circuitry for conditioning the electrical signals associated with the magnetic head can be fabricated as part of the substrate and be connected to one of the pair of wires. The electronic circuitry can, for example, amplify electrical drive signals associated with the magnetic head, be a recording sensor preamplifier, and/or provide ESD protection for the electrical signals associated with the magnetic head.