Hitachi Global Storage Technologies Netherlands B.v.

Jacey Robert Beaucage

Huey-Ming Tzeng

Xiao Z Wu

Paul Arthur Goddu

Linden James Crawforth

Tsai-Wei Wu

Jeffrey P Gunder

Eduardo Padilla

Timothy C Reiley

The lapping of a slider is controlled based on an amplitude of a readback signal which is produced from an externally applied magnetic field. A lapping plate is used to lap a slider which includes at least one magnetic head having a read sensor. During the lapping, a coil produces a magnetic field around the slider and processing circuitry monitors both a readback signal amplitude and a resistance of the read sensor. The lapping of the slider is terminated based on the monitoring both the readback signal amplitude and the resistance. Preferably, the lapping of the slider is terminated when the resistance is within a predetermined resistance range and the readback signal amplitude is above a predetermined minimum amplitude threshold or reaches its peak value. Asymmetry can also be measured in the described system, where the lapping process is terminated based on asymmetry as well as resistance and amplitude measurements.

Methods and apparatus for controlling the lapping of a slider based on an amplitude of a readback signal produced from an externally applied magnetic field

Apparatus for controlling the lapping of a slider based on an amplitude of a readback signal produced from an externally applied magnetic field

A method of precisely controlling the amount of flatness or curvature in a lapping plate is disclosed. The lapping plate is formed from two layers of metal alloys, such as tin-antimony and steel. A bimetallic effect is exploited to induce a linear expansion in the plate so that the flatness or curvature of the plate is manipulated with thermal cycling. The plate is machined and charged under very specific and tightly controlled temperatures to produce a very robust, flat plate charge. As temperature cycling induces a linear expansion along a single plane across the plate, the resultant flatness change is scalar with temperature, and can be repeated and controlled. When the plate laps magnetic sliders, the plate can be thermally cycled to produce a conical surface and a high crown-to-camber ratio can be achieved.

Method of achieving very high crown-to-camber ratios on magnetic sliders

A method of predicting the lapping property of a charged lapping plate uses samples with a known lap surface. The samples are lapped on the plate and a non-invasive sensor is used to determine the lapping rate under a fixed load and rotation speed. The total frictional force of the samples is measured during the lapping to calculate the friction and Preston coefficients of the plate. The samples are held in place while the plate rotates and the sensor measures the distance to the plate. The plate rotates for a specific time so that adequate removal of the pad material has occurred. The lapping rate is determined from a change in the gap distance over a time interval. The lapping rate and friction are then assessed to determine if the plate is lapping worthy.

Method of predicting plate lapping properties to improve slider fabrication yield

A device for predicting the lapping property of a charged lapping plate uses samples with a known lap surface. The samples are lapped on the plate and a non-invasive sensor is used to determine the lapping rate under a fixed load and rotation speed. The total frictional force of the samples is measured during the lapping to calculate the friction and Preston coefficients of the plate. The samples are held in place while the plate rotates and the sensor measures the distance to the plate. The plate rotates for a specific time so that adequate removal of the pad material has occurred. The lapping rate is determined from a change in the gap distance over a time interval. The lapping rate and friction are then assessed to determine if the plate is lapping worthy.

System and apparatus for predicting plate lapping properties to improve slider fabrication yield

A system and apparatus precisely controls the amount of flatness or curvature in a lapping plate. The lapping plate is formed from two layers of metal alloys, such as tin-antimony and steel. A bimetallic effect is exploited to induce a linear expansion in the plate so that the flatness or curvature of the plate is manipulated with thermal cycling. The plate is machined and charged under very specific and tightly controlled temperatures to produce a very robust, flat plate charge. As temperature cycling induces a linear expansion along a single plane across the plate, the resultant flatness change is scalar with temperature, and can be repeated and controlled. When the plate laps magnetic sliders, the plate can be thermally cycled to produce a conical surface and a high crown-to-camber ratio can be achieved.

System and apparatus for achieving very high crown-to-camber ratios on magnetic sliders

A lapping plate has photolithographically defined patterns that are electroplated to produce lands with well-defined channels. By choosing a particular geometry, the retention force is significantly reduced over prior art options, while still retaining a high land area fraction. In some versions, the material is electroplated onto sufficiently thin substrates to allow conformation to a curved vacuum chuck. This configuration provides a very large reduction in retraction force when compared to smooth, flat lapping plates. In addition, the substrate used to form the lapping plate has reduced thickness, and a vacuum chuck is used to pull the thin, flat lapping plate against it to define the curvature. This allows the lapping plate to be charged by a flat charging ring. The substrate used is typically glass and has been sputter-metallized on both sides. The resist is then patterned, leaving an exposed pattern in the metallization on both sides.

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San Jose, CA, United States of America

Jacey Robert Beaucage