Browse Prior Art Database

Lapping Fixture for Electrochemical Potential Control

IP.com Disclosure Number: IPCOM000119459D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 1 page(s) / 47K

Publishing Venue

IBM

Related People

Frankel, G: AUTHOR [+6]

Abstract

The fabrication of thin-film magneto-resistive heads from wafers into sliders involves exposing the component materials at the air bearing surface to a number of aqueous process solutions. Several of these materials including MnFe and tungsten are extremely susceptible to process corrosion. These materials will form a protective passive film under appropriate conditions of potential, pH, and presence of certain anions in solution. Effective control of electrochemical potential has been shown to be a critical parameter for an aqueous lapping process.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 92% of the total text.

Lapping Fixture for Electrochemical Potential Control

      The fabrication of thin-film magneto-resistive heads from
wafers into sliders involves exposing the component materials at the
air bearing surface to a number of aqueous process solutions.
Several of these materials including MnFe and tungsten are extremely
susceptible to process corrosion.  These materials will form a
protective passive film under appropriate conditions of potential,
pH, and presence of certain anions in solution.  Effective control of
electrochemical potential has been shown to be a critical parameter
for an aqueous lapping process.

      This article describes a novel method of controlling the
potential of the elements during the lapping process without the
addition of any electronic equipment.  The potential of the device
metallurgy is controlled by electrically connecting to the metallurgy
a large area of a metal which itself has a specific open circuit
potential. If the IR drop is not large, galvanic interaction between
the large metal area and the device metallurgy will result in
polarization of the device to the open circuit potential of the large
area.

      Implementation of this lapping process requires a modification
to the lapping fixture in which a piece of material that has the
desired electrochemical potential such as gold added to the system in
such a way that it is immersed in the lapping fluids during lapping
in close proximity to the devices, it does not contact...