International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Leland Stanford Junior University

Hgst Netherlands, B.v.

Sandia National Laboratories

Ciaran Avram Fox

Richard Hsiao

Jih-Shiuan Luo

Yiping Hsiao

Chin-Yu Yeh

Peter John Melz

Hardayal Singh Gill

Cherngye Hwang

Jila Tabib

Lydia Baril

Mustafa Pinarbasi

Thomas R Albrecht

Vladimir Nikitin

Edward Hin Pong Lee

Prakash Kasiraj

Lawrence S Pan

Wen-yaung Lee

Joseph Francis Smyth

Atul S Kumar

Robert Langland Smith

David Ernest Call

Richard Thomas Campbell

Kenneth David Mackay

Ray N M Tag-at

James Devereaux Jarrett

German Vergara

Renyu Cao

Ma V C Maceren

Virgil Simon Speriosu

In one embodiment, a method for determining electrostatic discharge (ESD) includes building a slider delta comparison map using slider electrical and/or row bar quasi testing results, wherein row bar quasi testing is performed on row bars of multiple sliders, and wherein slider electrical testing is performed on individual sliders, determining whether a test device in a parent job passes primary ESD delta criteria, when the test device fails the primary ESD delta criteria: flagging the parent job of the test device as a reroute job and performing automatic actual parts rerouting for any jobs related to the parent job to pull parts from a test bin as opposed to a supply bin, wherein all parts pulled from the test bin are tested prior to assembly as opposed to parts pulled from the supply bin which are not 100% tested.

Real time electrostatic discharge (ESD) detection

A method for testing a magnetic head to determine whether the magnetic head is unacceptably affected by temperature variations. The test includes testing the magnetic head at different temperatures and measuring either or both of a signal amplitude and a signal asymmetry of a signal from the magnetic head at the different temperatures. If signal amplitude or signal asymmetry vary excessively as a result of the temperature change then the head can be scrapped.

Method for testing the acceptability of a magnetic read sensor

A system, method and computer program product provide an annealing process for setting a magnetization condition of a read head. An amount of heat for stabilizing magnetization condition of a read head is calculated. A width and amplitude of a voltage pulse that generates the calculated amount of heat in the read head are calculated. A voltage pulse of the calculated width and amplitude is applied to the read head for generating Joule heating in the read head. The width of the voltage pulse is less than one second.

System and method for pre-stressing a read head for improving performance thereof

A spin valve (SV) sensor of the self-pinned type includes one or more compressive stress modification layers for reducing the likelihood that the pinning field will flip its direction. The spin valve sensor includes a capping layer formed over a spin valve structure which includes a free layer, an antiparallel (AP) self-pinned layer structure, and a spacer layer in between the free layer and the AP self-pinned layer structure. A compressive stress modification layer is formed above or below the capping layer, adjacent the AP self-pinned layer structure, or both. Preferably, the compressive stress modification layer is made of ruthenium (Ru) or other suitable material.

Self-pinned spin valve sensor with stress modification layers for reducing the likelihood of amplitude flip

A method is disclosed for testing pinned layers of magnetic disk drive read heads having at least one pinned layer, where the magnetic orientation of the pinned layers has been set in an initial direction. The method includes applying a large magnetic test field at a reverse canted reset angle. First test responses from the disk drive read heads are then measured in a small magnetic test field. A large magnetic test field is applied at normal canted reset angle. The disk drive heads are then subjected to a full suite of performance tests in a small magnetic test field to verify their acceptability. These second test responses are then compared to the first test responses to identify read heads having weakly pinned layers.

Reverse magnetic reset to screen for weakly pinned heads

Methods and apparatus for protecting read sensors from damage caused by electrostatic discharge (ESD) during manufacturing are described. Two electrical connections are formed and utilized for ESD protection: one primarily for early protection of the sensors (i.e. prior to cutting and lapping the wafer to form the ABS) and the other primarily for later protection of the sensors (i.e. after cutting and lapping the wafer to form the ABS). The first electrical connection is created between the read sensor and the first and second shields, and is severed when the wafer is cut and lapped along the ABS. The second electrical connection is formed between the sensor leads and the first and second shields, and is exposed on an outside surface of the magnetic head. The second electrical connection is severed late in the manufacturing process, preferably by laser-deletion.

Method of protecting read sensors from electrostatic discharge damage during the manufacture of magnetic heads

An automated production process for the screening of the read-width (RW) and/or the stripe-height (SH) for every magnetoresistive (MR) read sensor element in a wafer substrate. The method of this invention uses the RW and/or SH values found with optical examination by electron microscopy of several of the MR sensor elements to estimate two substrate coefficients that relates the optical RW and SH measurements to heating-delta measurements, &dgr;&equals;(RH&minus;RC)/RC, where RH is the sensor resistance when hot and RC is the sensor resistance when cold, both of which can be measured using automated equipment. These relationships are sufficiently similar among all MR sensor elements manufactured on a single wafer substrate during a single manufacturing procedure that, when the hot resistance RH is measured at a constant applied voltage, the heating-delta, may be used with a first substrate coefficient to estimate the read-width RW of each MR sensor element for quality-control purposes during manufacture. When the hot resistance RH is measured at a constant applied current, the heating-delta may be used with a second substrate coefficient to estimate the stripe-height SH of each MR sensor element for quality-control purposes during manufacture.

Method for the rapid measurement of magnetoresistive read head dimensions

Provided is a reactive ion etching (RIE) method for use in altering the flatness of a slider, whereby a slider or row of sliders is placed within a RIE apparatus. The apparatus comprises essentially an electrode within a chamber having an inlet and an outlet. The electrode is controlled by a bias power source. A source power is provided to the chamber to generate the plasma, wherein a gas or gas mixture is first introduced to the chamber and the source power is adjusted to maximize the plasma composition of ions and reactive neutral species. The ions and reactive neutral species are generated from reactive chemical species such as CHF and other F-containing species. An inert gas such as Argon may also be present. Typically, TiC within the Al O matrix of the slider substrate surface is etched at a faster rate than other substrate species.

Method of adjusting the flatness of a slider using selective plasma etching

A method of corrosion susceptibility testing of a magnetic recording head is disclosed. The method includes applying simulated disk corrosion products containing cobalt salts to the recording head. The recording head is then placed in an environmental chamber with elevated temperature and humidity. The resistance of the sensor on the recording head is measured after removal from the chamber and compared with the resistance before placement in the chamber. A significant change in resistance indicates a corrosion failure. This component level testing gives a more accurate indication of the corrosion performance of the recording head when placed in a disk drive.

Method for corrosion susceptibility testing of magnetic heads using simulated disk corrosion products

The invention relates to a method for producing magnetic sliders having a permanent protective coating of carbon over the air bearing surface. The method comprises the steps of: (a) depositing a temporary protective coating on a surface of the slider, the temporary protective coating comprising a layer carbon; (b) depositing a photoresist layer onto the temporary protective coating; (c) imagewise exposing the photoresist layer to radiation; (d) developing the image in the photoresist layer to expose the temporary protective coating; (e) transferring the image through the temporary protective coating and into the slider to form the air bearing pattern in the slider; (f) removing the temporary protective coating using nonreactive plasma; and (g) depositing a permanent protective coating comprising a layer of carbon.

Method for forming the air bearing surface of a slider using nonreactive plasma

The invention relates to a method for producing magnetic sliders having a permanent protective coating of carbon over the air bearing surface. The method comprises the steps of: (a) depositing a protective coating on a surface of the slider, the protective coating comprising an underlayer of carbon and a top layer selected from silicon and titanium; (b) depositing a photoresist layer onto the protective coating; (c) imagewise exposing the photoresist layer to radiation; (d) developing the image in the photoresist layer to expose the protective coating; (e) transferring the image through the protective layer and into the slider to form the air bearing pattern in the slider; and (f) removing the top layer of the protective coating.

Method for forming the air bearing surface of a slider

A cathode has electropositive atoms directly bonded to a carbon-containing substrate. Preferably, the substrate comprises diamond or diamond-like (sp.sup.3) carbon, and the electropositive atoms are Cs. The cathode displays superior efficiency and durability. In one embodiment, the cathode has a negative electron affinity (NEA). The cathode can be used for field emission, thermionic emission, or photoemission. Upon exposure to air or oxygen, the cathode performance can be restored by annealing or other methods. Applications include detectors, electron multipliers, sensors, imaging systems, and displays, particularly flat panel displays.

Carbon-containing cathodes for enhanced electron emission

A method is provided for resetting the magnetization of the pinned and hard biasing layers of a spin valve read head at the row level. In a first embodiment of the invention a first magnetic field is applied substantially perpendicular to the air bearing surface (ABS) at room temperature for setting the magnetic moment of the pinned layer substantially perpendicular to the ABS followed by applying a second magnetic field substantially parallel to the ABS for setting the magnetic moments of the hard biasing layers substantially parallel to the ABS. In a second embodiment of the invention the antiferromagnetic pinning layer is also reset. This is done by heating the pinning layer with a current pulse conducted through the leads to the conductive layers of the spin valve head so that localized heating takes place adjacent the pinning layer as contrasted to ambient heating of the spin valve head. Simultaneous with the localized heating the first magnetic field is applied for orienting the magnetic spins of the pinning layer perpendicular to the ABS and resetting the magnetic moment of the pinned layer perpendicular to the ABS in a single domain state. Subsequently, a second magnetic field is applied for resetting the magnetic moment of the hard biasing layer parallel to the ABS in a single domain state.

Growing community of inventors

Sunnyvale, CA, United States of America

Ciaran Avram Fox