International Business Machines Corporation

Pemstar, Inc.

Other

Nathaniel C Anderson

Robert Duane Ahmann

Larry E Daby

Hal Hjalmar Ottesen

Michael Joseph Ross

Patrick M McCaffrey

Mohammed Amine Hajji

Lubomyr Taras Romankiw

Steven F Starcke

Robert E Jones, Jr

Arlen John Bowen

Bruce A Murray

Gene A Johnson

Robert B Chesnutt

Charles R Grover, Jr

Marlin E Miner

Vincent D Gravdahl

Bruce W Wright

Robert B Chesnut

The present invention provides an ESD and EOS protection method and apparatus that can be easily implemented in existing disk drive designs and manufacturing process. One apparatus embodiment includes a first conductive member electrically connected to a first terminal of a magnetic head element; a second conductive member electrically connected to a first second terminal of the magnetic head element; and a variable conductive member, such as a variably conductive member. One method embodiment includes operably connecting a first conductive member to a first terminal of a magnetic head element; operably connecting a second conductive member to a second terminal of the magnetic head element; and operably connecting a variably conductive member, such as a variably conductive polymer, to the first conductive member and to the second conductive member. The variably conductive member in these embodiments acts as a conductor when a sufficiently high potential exists between the first conductive member and the second conductive member.

Electrostatic protection for magnetic heads

The present invention involves a photolithographic process, and apparatus and material for use therein, for producing etched or eroded areas or holes in a selected pattern on or in the surface of fine workpieces, such as small diameter tubes. One aspect of the present invention is a photolithographic process for producing a selected pattern on a nonplanar surface of a workpiece using at least one mask to define the selected pattern. The process includes the acts of applying a photoresist material to the workpiece and aligning the mask with the nonplanar surface of the workpiece. The mask may have an inner surface that corresponds to the nonplanar surface. The process may also include the acts of exposing and developing the photoresist material.

Photolithographic process for producing etched patterns on the surface of fine tubes, wires, or other three dimensional structures

The present invention relates to a head tester for testing heads having a read element and a write element. The tester comprises a substrate on which a read coil is positioned to be sensitive to the write element of the head. A write coil is also formed on the substrate and this coil is positioned such that the read element of the head to be tested is sensitive to the write coil.

Magnetic head tester with write coil and read coil

Photolithographic process for producing etched patterns on the surface of fine tubes, wires or other three dimensional structures

A magnetic disk drive includes redundant data written at a plurality of out of phase angular locations to reduce the latency and enhance performance during a read operation. The loss of recording capacity is reduced by increasing the data density to achieve the same soft error rate standard required for single recording. Dual recording also allows different recording codes to be used at the duplicated locations to thereby have the more highly stressed code words occur at different locations in the data to further reduce the possibility of an error. The redundant recording can be used in one portion of the media and normal recording used in another media portion to enable selection of the recording technique in accordance with the type of data being stored. The size of the normal and redundant recording portions can be controlled by the format operation and the user of the disk drive can intervene to designate the size of the redundant and normal media recording portions effected during the format operation.

Data recording device and control apparatus for recording data twice on

Disk drive with redundant recording

The mixed potential of a standard reference electrode and an electrically conductive article that is being electrolessly plated is compared to a DC reference voltage. A predetermined level of comparison indicates the start of electroless plating. This comparison starts a timer. After a predetermined time interval has expired, plating is terminated. The result is a plated coating that is uniform and of a closely controlled thickness. The article to be plated is a thin film magnetic recording disk upon which a thin cobalt containing layer, in the range of about 850 angstroms thick, is to be plated.

Method for electroless plating

A bath for electroplating a high cobalt magnetic alloy material suitable for fabrication of thin film heads. The ternary cobalt-nickel-iron (CoNiFe) alloy electroplating bath composition produces a high cobalt magnetic thin film having high saturation magnetization, a magnetostriction coefficient that is substantially zero, and low coercivity. A process suitable for deposition of the soft magnetic material provides a thin film head where 4.pi.Ms is higher than 14K gauss, Hc is less than 20e, 1-10 MHZ permeability is near 1000, and has a near zero magnetostriction.

Electrodepositing CoNiFe alloys for thin film heads

A film transducer head design is formed on a substrate where the first yoke layer and electric terminal strip that connects the coil center pad to the head exterior are formed at the same time followed by successive layers that form the transducer gap, coil insulation, coil, coil insulation and the second yoke layer. This sequence allows the coil to be tested immediately after deposition of the coil material and at a time in the fabrication sequence when it can be reworked or replaced if a discontinuity (open) or shorted turn(s) is (are) identified.

Thin film transducer

A film type magnetic transducer head has a yoke formed partially of high permeability material which provides enhanced read capabilities and partially of high saturation magnetization material to obtain the write function benefits associated therewith. The high saturation magnetization material is used in the pole tip region and extends to a location beyond the point of initial saturation and does not extend to a position at which the first coil winding is embraced to prevent or minimize coupling with the windings. With the balance of the joke of high permeability material, the transducer functions substantially as a wholly high saturation magnetization yoke in the write function and as a wholly high permeability material yoke for read purposes.

Composite thin film transducer head

Process for lift-off fabrication of sputtered dielectric or nonmagnetic gap materials and thin-film heads for either a single-element thin-film head or side-by-side elements on a thin-film head. The lift-off process utilizes a copper coating that is removed by a twenty percent solution of ammonium persulfate with a pH in the range of seven to nine to assure complete removal of gap material from the back closure of the thin-film head without damage to the underlying permalloy. The process can also be utilized to obtain a multiple layer deposits on a single thin-film had by repeating the steps of the process. The process provides for a clean hole, no dielectric on the surface nor any attacking on the magnetic material.

Process of lift off of material

A process for producing a reactive ion-etched structure with height and width dimensions of the order of 25 microns or less on a ferrite substrate surface is disclosed. A mask of positive water saturated photoresist is formed on the substrate. A metal taken from the group consisting of nickel and a nickel-iron alloy is plated through the mask. The photoresist mask is removed to leave a pattern in the plated metal. The ferrite substrate surface that is exposed by the pattern is reactive ion etched with a power density of &gt;1w/cm.sup.2 and a bias voltage &lt;-100 volts.

Thin film techniques for fabricating narrow track ferrite heads

Electroplating nickel-iron alloys onto objects having complex topographical shapes with projections and hollows such as upper pole pieces of thin film magnetic recording heads has been found to yield a substantial variation in nickel-iron alloy composition from point to point within a single pattern. Providing a low total dischargeable ion concentration in the bath is helpful to reduce such variations when plating in the 80:20 Ni:Fe alloy range. That is, it is desirable to use a low value of Fe.sup.++ and Ni.sup.++ ion concentrations and a relatively low current density to operate at the relatively flat peak of the curve of the iron percentage in the plated alloy vs. current density curve. The curve can be raised or lowered by increasing or decreasing the total dischargeable ion concentration respectively for a given Ni.sup.++ /Fe.sup.++ ion ratio. The preferred Fe.sup.++ ion concentration range for Ni:Fe alloy ratio near 80:20 is about 0.15-0.3 g/l for a range of 10-14 g/l of Ni.sup.++ ion in a solution with a pH of about 3, a temperature of about 20.degree.-35.degree. C. where the Ni.sup.++ /Fe.sup.++ ratio in the solution ranges from about 45 to 1 to about 70 to 1. Preferably, an electrolyte for reducing pitting such as 0-100 g/l of NaCl is employed. The cation (Na.sup.+) of the latter electrolyte should not be a dischargeable ion. Plating current density is preferably between about 2 ma/cm.sup.2 and 12 ma/cm.sup.2, and optimum results are achieved for values from about 4 to 8 ma/cm.sup.2.

Growing community of inventors

Pine Island, MN, United States of America

Nathaniel C Anderson