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In-Plane MagnetoResistive/Inductive Heads on Single Crystal Substrates

IP.com Disclosure Number: IPCOM000116031D
Original Publication Date: 1995-Jul-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 106K

Publishing Venue

IBM

Related People

Eldridge, JM: AUTHOR [+3]

Abstract

Disclosed is design of an in-plane combination MagnetoResistive (MR) and inductive magnetic recording head fabricated in the etch pits of single crystal substrates. The MR read sensor and the inductive write gap are stacked on the sloping side walls of the pits, which are anistropically etched into the substrate prior to film head deposition.

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In-Plane MagnetoResistive/Inductive Heads on Single Crystal Substrates

      Disclosed is design of an in-plane combination MagnetoResistive
(MR) and inductive magnetic recording head fabricated in the etch
pits of single crystal substrates.  The MR read sensor and the
inductive write gap are stacked on the sloping side walls of the
pits, which are anistropically etched into the substrate prior to
film head deposition.

      The invention is best understood by referring to the Figure
which shows a sectional view through the center of a completed head.
Important features of this design are (1) the Air Bearing Surface
(ABS) and tapers of the slider can be batch fabricated  over an
entire wafer by common micromachining techniques, and (2) the sliders
can be very thin because the magnetic head elements lie in the plane
of the slider.  The MR sensor and write gap are tilted approximately
45º  with respect to the ABS to effectively intercept the
magnetic flux from the disk.  The single crystal substrate on which
the head is to be built is chosen for its etchability, the desired
side wall angle of the etch pits, and the required durability of the
finished head.

      While a variety of crystals can be used, Single Crystal Silicon
(SCS) is particularly suited for this application.  Its
micromachining characteristics are well understood, and it is easily
etched anistropically in alkaline solutions such as KOIL.  For
example, rectangular pits with side wall angles equal to 54.7 degrees
are easily etched into (100) oriented SCS substrates.  The side walls
of the pits are formed by (111) crystallographic  planes.  Similarly,
rectangular mesas with (111) side walls can also be formed.  Other
side wall angles can be achieved with different crystal orientations.
The depth of the pits and height of the mesas is easily controlled by
common SCS etching techniques.

      Referring again to the Figure, substrate 10 and its
crystallographic orientation are chosen to achieve the desired etch
pit side walls 12 and side wall angles 13.  First, mesas in the shape
of the slider (ABS) are formed on the substrate by anistropic
etching.  Next, tapers are created by etching.  Then etch pits 11 are
formed at appropriate locations on the mesas, also by anistropic
etching.  All side walls are smooth and side wall angles 13 are well
controlled, because the walls are defined by crystallographic planes
in SCS.  The mesa edges 18, which ultimately become the rails edges,
are also very smooth because they are formed by chemical e...