U.S. patent application number 09/761034 was filed with the patent office on 2001-05-24 for planar stitched write head having write coil insulated with inorganic insulation.
Invention is credited to Dill, Frederick Hayes JR., Fontana, Robert E., Hsiao, Richard, Santini, Hugo Alberto Emilio.
Application Number | 20010001586 09/761034 |
Document ID | / |
Family ID | 22789636 |
Filed Date | 2001-05-24 |
United States Patent
Application |
20010001586 |
Kind Code |
A1 |
Dill, Frederick Hayes JR. ;
et al. |
May 24, 2001 |
Planar stitched write head having write coil insulated with
inorganic insulation
Abstract
A write head has a second pole tip layer, a coil layer and a
write coil insulation layer that are planarized at their top
surfaces. A thin top insulation layer insulates the top of the coil
layer from a yoke portion of the second pole piece which is
connected to the second pole tip layer in the pole tip region and
connected to a first pole piece layer in a back gap region. In a
preferred embodiment the write gap layer extends throughout the
yoke region and provides the only insulation between the first pole
piece layer and the coil layer. Further, it is preferred that the
write coil insulation layer be an inorganic material such as
silicon dioxide (SiO.sub.2). Several embodiments of the write head
are provided along with novel methods of making.
Inventors: |
Dill, Frederick Hayes JR.;
(S. Salem, NY) ; Fontana, Robert E.; (San Jose,
CA) ; Hsiao, Richard; (San Jose, CA) ;
Santini, Hugo Alberto Emilio; (San Jose, CA) |
Correspondence
Address: |
Ervin F. Johnston
International Business Machines Corporation
5600 Cottle Road
San Jose
CA
95193
US
|
Family ID: |
22789636 |
Appl. No.: |
09/761034 |
Filed: |
January 16, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09761034 |
Jan 16, 2001 |
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09212119 |
Dec 15, 1998 |
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Current U.S.
Class: |
360/123.29 ;
G9B/5.086 |
Current CPC
Class: |
B82Y 10/00 20130101;
G11B 5/3967 20130101; G11B 5/313 20130101; Y10T 29/49044
20150115 |
Class at
Publication: |
360/126 |
International
Class: |
G11B 005/31 |
Claims
We claim:
1. A method of making a magnetic head that has an air bearing
surface (ABS) and a yoke region between a pole tip region and a
back gap region wherein the pole tip region is partially bounded by
an air bearing surface (ABS) site that corresponds to said ABS,
comprising: forming a ferromagnetic first pole piece in the pole
tip, yoke and back gap regions; forming a nonmagnetic write gap
layer on the first pole piece in the pole tip region; forming a
second pole tip layer with a first thickness on the write gap layer
in the pole tip region; forming a write coil as follows: forming a
write coil insulation layer with a second thickness on the second
pole tip layer and on the yoke and back gap regions of the first
pole piece with a write coil opening at a location where a write
coil is to be formed; forming a write coil material layer with a
third thickness on the write coil insulation layer and in the write
coil opening; each of the second and third thicknesses being
greater than the first thickness; and first grinding away a portion
of each of the write coil insulation layer and the write coil
material layer until the write coil is formed with the write coil
and the write coil insulation layer having a first common flat
surface.
2. A method as claimed in claim 1 wherein said forming of the write
gap layer also includes forming the write gap layer on the first
pole piece in the yoke and back gap regions.
3. A method as claimed in claim 1 wherein said first grinding is
chemical mechanical polishing (CMP).
4. A method as claimed in claim 1 wherein said forming of the write
coil further includes: after forming the write coil insulation
layer forming an electrically conductive first seed layer on said
write coil insulation layer and in said write coil opening; and
plating said write coil material layer.
5. A method as claimed in claim 1 including: forming a second pole
piece layer connected to the second pole tip layer at a location
recessed from said ABS site.
6. A method as claimed in claim 1 including: removing a portion of
the write coil insulation layer in the back gap region to expose
the first pole piece in the back gap region; forming an
electrically insulative top insulation layer on said first common
flat surface leaving the second pole tip layer and the back gap
region of the first pole piece exposed; and forming a second pole
piece layer on said top insulation layer and connected to the
second pole tip layer in the pole tip region and connected to the
first pole piece at said back gap.
7. A method as claimed in claim 6 wherein said forming of the write
gap layer also includes forming the write gap layer directly on the
first pole piece in the yoke and back gap regions.
8. A method as claimed in claim 7 wherein said step of removing a
portion of the write coil insulation layer in the back gap region
also includes removing a portion of the write gap layer in the back
gap region.
9. A method as claimed in claim 6 including: said forming of the
first pole piece includes forming a first pole piece with a
pedestal portion with a fourth thickness in the pole tip region and
a recessed portion in the yoke and back gap regions; depositing an
aluminum oxide (Al.sub.2O.sub.3) recessed insulation layer on the
pedestal portion and in the recessed portion of the first pole
piece with a fifth thickness in said recessed portion; the fifth
thickness being greater than the fourth thickness; and second
grinding away a portion of the recessed insulation layer until the
recessed layer and the pedestal portion of the first pole piece
commonly form a second common flat surface.
10. A method as claimed in claim 9 wherein said forming of the
write gap layer also includes forming the write gap layer directly
on the recessed insulation layer in the yoke and back gap
regions.
11. A method as claimed in claim 10 wherein said step of removing a
portion of the write coil insulation layer in the back gap region
also includes removing a portion of the write gap layer in the back
gap region.
12. A method as claimed in claim 1 wherein said forming of the
write coil insulation layer includes: forming a write coil
insulation material layer of etchable material with said second
thickness on the second pole tip layer and on the yoke and back gap
regions of the first pole piece; forming a photoresist material
layer on the write coil insulation material layer; patterning the
photoresist material layer to provide a patterned photoresist layer
with a photoresist layer opening exposing a portion of the write
coil insulation material layer corresponding to a location of the
write coil; etching through the photoresist layer opening to remove
the exposed portion of the write coil insulation material layer to
provide said write coil insulation layer with said write coil
opening; the etching being selective to the write coil insulation
material layer with respect to the patterned photoresist layer; and
removing said patterned photoresist layer.
13. A method as claimed in claim 12 wherein said forming of the
write gap layer also includes forming the write gap layer directly
on the first pole piece in the yoke and back gap regions.
14. A method as claimed in claim 13 wherein said write gap layer is
aluminum oxide (Al.sub.2O.sub.3) and is aligned within said pattern
opening and is an etch stop after etching of the write coil
insulation material layer for protecting said first pole piece from
etching.
15. A method as claimed in claim 12 wherein said etchable material
is silicon dioxide (SiO.sub.2) and said etching is reactive ion
etching (RIE) with a fluorine base.
16. A method as claimed in claim 15 wherein said forming of the
write gap layer also includes forming the write gap layer directly
on the first pole piece in the yoke and back gap regions.
17. A method as claimed in claim 16 wherein said write gap is
aluminum oxide (Al.sub.2O.sub.3) and is aligned within said pattern
opening and is an etch stop after etching of the write coil
insulation layer material layer for protecting said first pole
piece from etching.
18. A method as claimed in claim 12 including: said forming of the
first pole piece includes forming a first pole piece with a
pedestal portion with a fourth thickness in the pole tip region and
a recessed portion in the yoke and back gap regions; depositing an
aluminum oxide (Al.sub.2O.sub.3) recessed insulation layer on the
pedestal portion and in the recessed portion of the first pole
piece with a fifth thickness in said recessed portion; the fifth
thickness being greater than the fourth thickness; and second
grinding away a portion of the recessed insulation layer until the
recessed layer and the pedestal portion of the first pole piece
commonly form a second common flat surface.
19. A method as claimed in claim 18 wherein said forming of the
write gap layer also includes forming the write gap layer directly
on the recessed insulation layer in the yoke and back gap
regions.
20. A method as claimed in claim 19 wherein said step of removing a
portion of the write coil insulation layer in the back gap region
also includes removing a portion of the write gap layer in the back
gap region.
21. A method as claimed in claim 20 wherein said etchable material
is silicon dioxide (SiO.sub.2) and said etching is reactive ion
etching (RIE) with a fluorine base.
22. A method of making a magnetic head that has an air bearing
surface (ABS) and a yoke region between a pole tip region and a
back gap region wherein the pole tip region is partially bounded by
an air bearing surface (ABS) site that corresponds to said ABS,
comprising: forming a ferromagnetic first pole piece in the pole
tip, yoke and back gap regions; forming a nonmagnetic write gap
layer on the first pole piece in the pole tip region; forming a
second pole tip layer with a first thickness on the write gap layer
in the pole tip region; any forming a write coil as follows:
forming a write coil insulation material layer of etchable material
with a second thickness on the second pole tip layer and on the
yoke and back gap bit regions of the first pole piece; forming a
photoresist layer on the write coil insulation material; patterning
the photoresist layer to provide a patterned photoresist layer with
a photoresist layer opening that exposes a portion of the write
coil insulation material layer where the write coil is to be
formed; and etching the exposed portion of the write coil
insulation material layer through said photoresist layer opening to
provide a write coil insulation layer with a write coil opening for
said write coil; removing said photoresist layer; plating a seed
layer on the write coil insulation layer and into said write coil
opening; plating a write coil material layer with a third thickness
onto the write coil insulation layer and into said write coil
opening; each of the second and third thicknesses being greater
than the first thickness; grinding away a portion of each of the
write coil insulation layer and the write coil material layer to
form a write coil, to form the write coil insulation material layer
into a write coil insulation layer located between turns of the
write coil and to form the write coil and the write coil insulation
layer with a first common flat surface; forming a second
photoresist layer on the first common flat surface; photopatterning
the second photoresist layer to provide a second patterned
photoresist layer opening that exposes a portion of the write coil
insulation layer in the back gap region; removing the exposed
portion of the write coil insulation layer and exposing a portion
of the first pole piece in the back gap region; forming a top
insulation layer on the flat surface of the write coil layer; and
forming a second pole piece layer on the top insulation layer and
connecting the second pole piece layer to the second pole tip layer
in the pole tip region and to the first pole piece in said back gap
region.
23. A method as claimed in claim 22 wherein, before forming the
first pole piece, forming a read head comprising: forming a
ferromagnetic first shield layer; forming a nonmagnetic
electrically insulative first gap layer on the first shield layer;
forming a read sensor with first and second lead layers on the
first gap layer; forming a nonmagnetic electrically insulative
second gap layer on the read sensor, the first and second lead
layers and the first gap layer; and employing the first pole piece
as a second shield layer.
24. A method as claimed in claim 23 wherein said forming of the
write gap layer also includes forming the write gap layer directly
on the first pole piece in the yoke and back gap regions.
25. A method as claimed in claim 24 wherein said write gap is
aluminum oxide (Al.sub.2O.sub.3) and is aligned within said pattern
opening and is an etch stop after etching of the write coil
material layer for protecting said first pole piece from
etching.
26. A method as claimed in claim 25 wherein said etchable material
is silicon dioxide (SiO.sub.2) and said etching is reactive ion
etching (RIE) with a fluorine base.
27. A method as claimed in claim 23 including: said forming of the
first pole piece includes forming a first pole piece with a
pedestal portion with a fourth thickness in the pole tip region and
a recessed portion in the yoke and back gap regions; depositing an
aluminum oxide (Al.sub.2O.sub.3) recessed insulation layer on the
pedestal portion and in the recessed portion of the first pole
piece with a fifth thickness in said recessed portion; the fifth
thickness being greater than the fourth thickness; and grinding
away a portion of the recessed insulation layer until the recessed
layer and the pedestal portion of the first pole piece form a
second common flat surface.
28. A method as claimed in claim 27 wherein said forming of the
write gap layer also includes forming the write gap layer directly
on the recessed insulation layer in the yoke and back gap
regions.
29. A method as claimed in claim 28 wherein said etchable material
is silicon dioxide (SiO.sub.2) and said etching is reactive ion
etching (RIE) with a fluorine base.
30. A magnetic head that has an air bearing surface (ABS) and a
yoke region between a pole tip region and a back gap region wherein
the pole tip region is partially bounded by said ABS, comprising: a
first pole piece that is located in said pole tip, yoke and back
gap regions; a write gap layer on the first pole piece in said pole
tip region; a second pole tip layer with a first surface on the
write gap layer in the pole tip region; a coil layer having
multiple spaced apart turns with a second surface on the first pole
piece in the yoke region; a write coil insulation layer with a
third surface located between the turns of the coil layer and
between the coil layer and the second pole tip layer; the first,
second and third surfaces forming a first common flat surface; a
top insulation layer on the common flat surface covering the second
surface of the turns of the coil layer; and a second pole piece
layer on the top insulation layer and engaging the second pole tip
layer in the pole tip region and engaging the first pole piece in
the back gap region.
31. A magnetic head as claimed in claim 30 wherein the write gap
layer extends through the yoke region.
32. A magnetic head as claimed in claim 30 wherein the write gap
layer is the only layer insulating the coil layer from the first
pole piece.
33. A magnetic head as claimed in claim 32 wherein the recessed
insulation layer, the write gap layer and the top insulation layer
are aluminum oxide (Al.sub.2O.sub.3) and the write coil insulation
layer is silicon dioxide (SiO.sub.2).
34. A magnetic head as claimed in claim 30 including: the first
pole piece having a pedestal in the pole tip region and a recessed
portion in the yoke region; and a nonconductive electrically
insulative recessed insulation layer located in said recessed
portion of the first pole piece.
35. A magnetic head as claimed in claim 34 wherein the recessed
insulation layer, the write gap layer and the top insulation layer
are aluminum oxide (Al.sub.2O.sub.3) and the write coil insulation
layer is silicon dioxide (SiO.sub.2).
36. A magnetic head as claimed in claim 30 including a read that
comprises: first and second nonmagnetic electrically insulative
first and second gap layers; a read sensor and first and second
lead layers located between the first and second gap layers; a
ferromagnetic first shield layer; the first and second gap layers
being located between the first shield layer and the first pole
piece.
37. A magnetic head as claimed in claim 36 wherein the write gap
layer is the only layer insulating the coil layer from the first
pole piece.
38. A magnetic head as claimed in claim 36 including: the first
pole piece having a pedestal in the pole tip region and a recessed
portion in the yoke region; and a nonconductive electrically
insulative recessed insulation layer located in said recessed
portion of the first pole piece.
39. A magnetic disk drive that includes a magnetic head that has an
air bearing surface (ABS) and a yoke region between a pole tip
region and a back gap region wherein the pole tip region is
partially bounded by said ABS, the disk drive comprising: the
magnetic head including a combined read head and write head; the
read head including: first and second ferromagnetic shield layers:
first and second nonmagnetic electrically insulative gap layers
located between the first and second ferromagnetic shield layers; a
read sensor responsive to applied magnetic fields and first and
second lead layers connected to the read sensor; the read sensor
and the first and second lead layers being located between the
first and second gap layers; the write head including: a first pole
piece that is located in said pole tip, yoke and back gap regions,
the first pole piece being a common layer with said second shield
layer; a write gap layer on the first pole piece in said pole tip
region; a second pole tip layer with a first surface on the write
gap layer in the pole tip region; a coil layer having multiple
spaced apart turns with a second surface on the first pole piece in
the yoke region; a write coil insulation layer with a third surface
located between the turns of the coil layer and between the coil
layer and the second pole tip layer; the first, second and third
surfaces forming a first common flat surface; a top insulation
layer on the common flat surface covering the second surface of the
turns of the coil layer; and a second pole piece layer on the top
insulation layer and engaging the second pole tip layer in the pole
tip region and engaging the first pole piece in the back gap
region; a housing; a magnetic disk rotatably supported in the
housing; a support mounted in the housing for supporting the
magnetic head with its ABS facing the magnetic disk so that the
magnetic head is in a transducing relationship with the magnetic
disk; means for rotating the magnetic disk; positioning means
connected to the support for moving the magnetic head to multiple
positions with respect to said magnetic disk; and processing means
connected to the magnetic head, to the means for rotating the
magnetic disk and to the positioning means for exchanging signals
with the merged magnetic head, for controlling movement of the
magnetic disk and for controlling the position of the magnetic
head.
40. A magnetic disk drive as claimed in claim 39 wherein the write
gap layer is the only layer insulating the coil layer from the
first pole piece.
41. A magnetic disk drive as claimed in claim 40 wherein the
recessed insulation layer, the write gap layer and the top
insulation layer are aluminum oxide (Al.sub.2O.sub.3) and the write
coil insulation, layer is silicon dioxide (SiO.sub.2).
42. A magnetic disk drive as claimed in claim 39 including: the
first pole piece having a pedestal in the pole tip region and a
recessed portion in the yoke region; and a nonconductive
electrically insulative recessed insulation layer located in said
recessed portion of the first pole piece.
43. A magnetic disk drive as claimed in claim 42 wherein the
recessed insulation layer, the write gap layer and the top
insulation layer are aluminum oxide (Al.sub.2O.sub.3) and the write
coil insulation layer is silicon dioxide (SiO.sub.2).
44. A magnetic head that has an air bearing surface (ABS) and a
yoke region between a pole tip region and a back gap region wherein
the pole tip region is partially bounded by said ABS, comprising: a
first pole piece that is located in said pole tip, yoke and back
gap regions; a write gap layer on the first pole piece in said pole
tip region; a second pole piece layer with a first surface on the
write gap layer in the pole tip region; a coil layer having
multiple spaced apart turns with a second surface on the first pole
piece in the yoke region; a write coil non-organic insulation layer
with a third surface located between the turns of the coil layer
and between the coil layer and the second pole tip layer; and the
second and third surfaces forming a first common flat surface; a
top insulation layer on the common flat surface covering the second
surface of the turns of the coil layer; and said second pole piece
layer being on the top insulation layer and engaging the first pole
piece in the back gap region.
45. A magnetic head as claimed in claim 44 including: the second
pole piece layer having a second pole tip portion and a second yoke
portion; the second pole tip portion having said first surface and
the yoke portion being on the top insulation layer and being
connected to the first pole piece in the back gap region; and the
first, second and third surfaces being coplanar.
46. A magnetic head as claimed in claim 45 including: the write gap
layer extending through the yoke region; the second pole tip
portion having a fourth surface, the coil layer having a fifth
surface and the non-organic insulation layer having a sixth
surface; and the fourth, fifth and sixth surfaces being located on
the write gap layer and being coplanar.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a planar stitched write
head having a write coil that is insulated by inorganic insulation
and, more particularly, to a write head having a second pole tip
and coil layer that are planarized with silicon dioxide located
between the turns of the coil layer and between the coil layer and
the second pole tip.
[0003] 2. Description of the Related Art
[0004] The heart of a computer is an assembly that is referred to
as a magnetic disk drive. The magnetic disk drive includes a
rotating magnetic disk, write and read heads that are suspended by
a suspension arm above the rotating disk and an actuator that
swings the suspension arm to place the read and write heads over
selected circular tracks on the rotating disk. The read and write
heads are directly mounted on a slider that has an air bearing
surface (ABS). The suspension arm biases the slider into contact
with the surface of the disk when the disk is not rotating but,
when the disk rotates, air is swirled by the rotating disk adjacent
the ABS to cause the slider to ride on an air bearing a slight
distance from the surface of the rotating disk. When the slider
rides on the air bearing the write and read heads are employed for
writing magnetic impressions to and reading magnetic impressions
from the rotating disk. The read and write heads are connected to
processing circuitry that operates according to a computer program
to implement the writing and reading functions.
[0005] The write head includes a coil layer embedded in first,
second and third insulation layers (insulation stack), the
insulation stack being sandwiched between first and second pole
piece layers. A gap is formed between the first and second pole
piece layers by a gap layer at an air bearing surface (ABS) of the
write head and the pole piece layers are connected at a back gap
which is recessed from the ABS. Current conducted to the coil layer
induces a magnetic field across the gap between the pole pieces.
This field fringes across the gap at the ABS for the purpose of
writing information in tracks on moving media, such as a tape in a
tape drive or in circular tracks on the aforementioned rotating
disk.
[0006] Since the second pole tip is generally the last pole tip to
pass locations on the circular track of a rotating disk, it is
important that the width of the second pole tip be as narrow as
possible for increasing the track width density of the write head.
The track width density is expressed in the art as tracks per inch
(TPI). Research efforts have narrowed this track width thereby
increasing magnetic disk drive capabilities from kilobytes to
megabytes to gigabytes. An ongoing problem in the art, however, is
producing a narrow second pole tip with good side wall definition.
The second pole tip is typically made by patterning photoresist
that has an opening where the second pole tip is to be plated.
Unfortunately, the high topography behind the second pole tip in
typical write heads causes light to be reflected toward the ABS
during a light exposure step of the photoresist adjacent the
desired side walls of the second pole tip. This light exposes
photoresist adjacent to the intended side walls which, upon
developing, is removed and causes an irregularity when the second
pole tip is plated. A main contributor to this high topography is
the insulation stack where the coil layer is embedded and a seed
layer covering the insulation stack that is highly reflective. A
reduction in this topography decreases what is known in the art as
"reflective notching" so as to produce a more highly defined second
pole tip.
[0007] The aforementioned high topography behind the second pole
tip also degrades the performance of the yoke portion of the second
pole piece which extends from the second pole tip to the back gap
if the yoke is deposited by sputtering techniques. When the yoke
portion of the second pole piece slopes down from the high
topography to the second pole tip, it makes a curve which changes
its magnetic properties. Some of these properties are uniaxial
anisotropy field (H.sub.K) and coercivity (H.sub.C). Accordingly,
it would be desirable to construct a planar second pole piece so
that its magnetic properties would not be altered. Still a further
problem of the high topography is that after completion of the head
a thick overcoat layer is required in order to protect the yoke and
pole tip portions of the head.
[0008] The aforementioned insulation stack is typically made from
various layers of hard baked photoresist. In the construction
sequence a layer of photoresist is spun on a wafer which is
substantially planarized thereacross. The photoresist layer is then
photopatterned with light exposing areas that are to be removed.
The photoresist layer is then developed with a developer which
causes the exposed areas to dissolve so they can be removed. The
layer is then soft baked at a temperature of 90.degree.-120.degree.
C. which causes the layer to solidify with rounded edges. After
constructing a coil layer on a soft baked photoresist layer one or
more additional photoresist layers may be constructed and soft
baked in the same manner. Thereafter, the photoresist layers are
hard baked at a temperature of 230.degree. C. which hardens the
photoresist layers. Photoresist is an organic material that has a
different coefficient of expansion than other materials in the
head, such as aluminum oxide (Al.sub.2O.sub.3) employed for the
overcoat layer. When the magnetic head is operating within a disk
drive its operating temperature is at least above 100.degree. C.
This causes the hard baked photoresist insulation stack to expand
more than the overcoat layer which causes the overcoat layer to
protrude beyond the pole tips at the ABS. This protrusion can ruin
the head or severely degrade its performance. Further, the hard
baking, of the photoresist layers can result in loss of signal
amplitude for some read sensors, such as spin valve sensors, in an
adjoining read head. The hard baked temperatures cause some
intermixing of the materials of the layers which can significantly
degrade their performance. Still further, the hard baked
photoresist insulation stack has poor heat dissipation which
aggravates all of the aforementioned problems.
[0009] A recap of the aforementioned problems is as follows:
[0010] (1) Difficulty of second pole tip track width definition
because of severe topography;
[0011] (2) Magnetic property change of a sputtered yoke portion of
the second pole piece as it curves over severe topography;
[0012] (3) Requirement for thick overcoat deposition;
[0013] (4) Protrusion of the overcoat layer at the ABS due to
thermal expansion of a hard baked photoresist insulation stack;
[0014] (5) Signal amplitude loss of some spin valve sensors due to
hard baking of the photoresist layers; and
[0015] (6) Inadequate heat dissipation of the hard baked
photoresist insulation stack.
SUMMARY OF THE INVENTION
[0016] The first three problems, mentioned hereinabove, are
overcome in the present invention by providing a write head wherein
the second pole tip and the write coil are planarized at their top
surfaces. The write head includes a first pole piece that is
located in pole tip, yoke and back gap regions. The write gap layer
is located on the first pole piece in the pole tip region and a
second pole tip layer is located on the write gap layer in the pole
tip region. The coil layer, which has multiple spaced apart turns,
is located on the first pole piece in the yoke region and a write
coil insulation layer is located between the turns of the coil and
between the coil layer and the second pole tip layer. The second
pole tip layer, the coil layer and the insulation layer have top
surfaces which lie within a common flat surface. A thin top
insulation layer covers the top surface of the turns of the coil
layer and a second pole piece layer is on top of the top insulation
layer, engages the second pole tip layer in the pole tip region and
engages the first pole piece in the back gap region. The second
pole tip can be constructed with high track width definition
because the patterned photoresist layer is on a flat surface
instead of a sloping surface typically found in the prior art. The
yoke of the second pole piece layer is nearly flat except for the
slight step of the top insulation layer which results in
substantially no change in magnetic properties of the yoke portion
of the second pole piece. Further, because of the overall lack of
topography the overcoat deposition can be much thinner than that
employed in the prior art.
[0017] The last three problems mentioned hereinabove are overcome
in the present invention by employing an inorganic material for the
write coil insulation layer between the turns of the coil and
between the coil layer and the second pole tip. This material is
preferably silicon dioxide (SiO.sub.2). Silicon dioxide has a
similar coefficient of expansion as aluminum oxide
(Al.sub.2O.sub.3) thereby obviating the protrusion of the aluminum
oxide overcoat layer at the ABS. Further, silicon dioxide does not
require hard baking at a high temperature which can result in
degrading some of the spin valve structures used in read heads.
Still further, the silicon dioxide is a better heat dissipator than
hard baked photoresist.
[0018] After constructing the first pole piece, the write gap layer
and the second pole tip layer a unique method is employed for
forming the write coil. First, a write coil mask is formed on the
second pole tip layer and on the yoke and back gap regions of the
first pole piece with a write coil mask opening at a location where
the write coil is to be formed. A write coil material layer is then
formed on the write coil mask and in the write coil mask opening.
The thicknesses of the write coil mask and the write coil material
layer are thicker than the thickness of the second pole tip layer.
A grinding operation is then employed to grind away a portion of
each of the write coil mask and the write coil material layer until
the write coil is formed and the write coil and the write coil mask
have a common flat surface. The common flat surface is instrumental
in substantially planarizing the yoke portion of the second pole
piece layer.
[0019] An object of the present invention is to provide a more
highly defined second pole tip of a write head, planarize the yoke
portion of the second pole piece layer and decrease the required
thickness of an overcoat layer.
[0020] Another object is to provide a write head wherein the
coefficient of expansions of the various layers of a write head are
more similar so as to prevent protrusion of the overcoat layer at
the ABS, eliminate hard baking of photoresist insulation layers of
the insulation stack so as to prevent degradation of a spin valve
sensor in a read head and improve heat dissipation by providing an
insulation stack with improved thermal conductivity.
[0021] A further object is to provide a write head which has a
combination of the features set forth in the first and second
objects hereinabove.
[0022] Still another object is to provide a unique method of making
a write head which has the features set forth hereinabove.
[0023] Other objects and attendant advantages of the invention will
become apparent upon reading the specification taken together with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a planar view of an exemplary magnetic disk
drive;
[0025] FIG. 2 is an end view of a slider with a magnetic head of
the disk drive as seen in plane 2-2;
[0026] FIG. 3 is an elevation view of the magnetic disk drive
wherein multiple disks and magnetic heads are employed;
[0027] FIG. 4 is an isometric illustration of an exemplary
suspension system for supporting the slider and magnetic head;
[0028] FIG. 5 is an ABS view of the slider taken along in plane 5-5
of FIG. 2;
[0029] FIG. 6 is a partial view of the slider and magnetic head as
seen in plane 6-6 of FIG. 2;
[0030] FIG. 7 is a partial ABS view of the slider taken along plane
7-7 of FIG. 6 to show the read and write elements of the magnetic
head;
[0031] FIG. 8 is a view taken along plane 8-8 of FIG. 6 with all
material above the write coil removed;
[0032] FIG. 9 is a side elevation view of one embodiment of the
present invention;
[0033] FIG. 10 is a view taken along plane 10-10 of FIG. 9;
[0034] FIG. 11 is a side elevation view of another embodiment of
the present invention;
[0035] FIG. 12 is a view taken along plane 12-12 of FIG. 11;
[0036] FIG. 13 is a side elevation view of the construction of a
first pole piece of the write head embodiment shown in FIGS. 9 and
10;
[0037] FIG. 14 is the same as FIG. 13 except the first pole piece
has been ion milled in order to provide a pedestal at the ABS and a
recessed portion therebehind;
[0038] FIG. 15 is the same as FIG. 14 except a layer of aluminum
oxide (Al.sub.2O.sub.3) has been sputtered onto the first pole
piece;
[0039] FIG. 16 is the same as FIG. 15 except the wafer has been
chemically mechanically polished (CMP) to provide a planar surface
of the aluminum oxide (Al.sub.2O.sub.3) layer and the pedestal
portion of the first pole piece;
[0040] FIG. 17 is the same as FIG. 16 except a write gap layer has
been formed;
[0041] FIG. 18 is the same as FIG. 17 except a second pole tip has
been formed;
[0042] FIG. 19 is the same as FIG. 18 except a write coil mask
material layer of etchable material has been formed on the second
pole tip layer in the pole tip region and on the first pole piece
in the yoke region and therebeyond;
[0043] FIG. 20 is the same as FIG. 19 except a photoresist layer
has been formed on the write coil mask material layer with
photoresist layer openings exposing portions of the write coil mask
material layer corresponding to a location of the write coil;
[0044] FIG. 21 is the same as FIG. 20 except the write coil mask
material layer has been etched down to the write gap layer;
[0045] FIG. 22 is the same as FIG. 21 except the photoresist mask
has been removed;
[0046] FIG. 23 is the same as FIG. 22 except a copper layer has
been plated or sputter deposited on the wafer;
[0047] FIG. 24 is the same as FIG. 23 except the wafer has been
chemically mechanically polished (CMP) to provide a planar surface
of the top surfaces of the second pole tip, the write coil layer
and the write coil insulation material therebetween;
[0048] FIG. 25 is the same as FIG. 24 except a top insulation layer
has been formed on top of the write coil;
[0049] FIG. 26 is the same as FIG. 25 except a photoresist mask has
been formed and the write coil insulation between the write coil
and the write gap therebelow have been etched away for a back gap
connection;
[0050] FIG. 27 is the same as FIG. 26 except the yoke portion of
the second pole piece has been formed on top of the top insulation
layer with connections to the second pole tip in the pole tip
region and to the first pole piece at the back gap;
[0051] FIG. 28 is a view taken along plane 28-28 of FIG. 27 with an
overcoat layer formed;
[0052] FIG. 29 illustrates in block form subsequent steps to
complete the magnetic head and mount it in a disk drive;
[0053] FIG. 30 is a side elevation illustration of the first pole
piece of the embodiment of the invention shown in FIGS. 11 and
12;
[0054] FIG. 31 is the same as FIG. 30 except a write gap layer has
been formed thereon;
[0055] FIG. 32 is the same as FIG. 31 except the second pole tip
has been formed in the pole tip region;
[0056] FIG. 33 is the same as FIG. 32 except a write coil mask
material layer of etchable material has been formed on the second
pole tip in the pole tip region and on the first pole piece in the
yoke region and therebeyond;
[0057] FIG. 34 is the same as FIG. 33 except a photoresist layer
has been photopatterned on the write coil mask material layer with
openings exposing a portion of the write coil mask material layer
at a location where the write coil is to be formed;
[0058] FIG. 35 is the same as FIG. 34 except reactive ion etching
(RIE) has been implemented to etch the write coil mask material
layer with openings down to the gap layer;
[0059] FIG. 36 is the same as FIG. 35 except the photoresist layer
has been removed;
[0060] FIG. 37 is the same as FIG. 36 except a write coil material
layer has been plated or sputter deposited;
[0061] FIG. 38 is the same as FIG. 37 except the wafer has been
chemically mechanically polished (CMP) to provide a planar surface
of the top surface of the second pole tip, the coil layer and the
write coil insulation material therebetween;
[0062] FIG. 39 is the same as FIG. 38 except a top insulation layer
has been formed on top of the write coil layer;
[0063] FIG. 40 is the same as FIG. 39 except a photoresist layer
has been photopatterned and the wafer has been etched to provide an
opening at the back gap;
[0064] FIG. 41 is the same as FIG. 40 except the photoresist layer
has been removed and the yoke portion of the second pole piece has
been formed on top of the write coil insulation layer and connected
to the second pole tip in the pole tip region and connected to the
first pole piece in the back gap region; and
[0065] FIG. 42 is a view taken along plane 42-42 of FIG. 41 with an
overcoat layer formed.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Magnetic Disk Drive
[0066] Referring now to the drawings wherein like reference
numerals designate like or similar parts throughout the several
views, FIGS. 1-3 illustrate a magnetic disk drive 30. The drive 30
includes a spindle 32 that supports and rotates a magnetic disk 34.
The spindle 32 is rotated by a motor 36 that is controlled by a
motor controller 38. A combined read and write magnetic head 40 is
mounted on a slider 42 that is supported by a suspension 44 and
actuator arm 46. A plurality of disks, sliders and suspensions may
be employed in a large capacity direct access storage device (DASD)
as shown in FIG. 3. The suspension 44 and actuator arm 46 position
the slider 42 so that the magnetic head 40 is in a transducing
relationship with a surface of the magnetic disk 34. When the disk
34 is rotated by the motor 36 the slider is supported on a thin
(typically, 0.05 .mu.m) cushion of air (air bearing) between the
surface of the disk 34 and the air bearing surface (ABS) 48. The
magnetic head 40 may then be employed for writing information to
multiple circular tracks on the surface of the disk 34, as well as
for reading information therefrom. Processing circuitry 50
exchanges signals, representing such information, with the head 40,
provides motor drive signals for rotating the magnetic disk 34, and
provides control signals for moving the slider to various tracks.
In FIG. 4 the slider 42 is shown mounted to a suspension 44. The
components described hereinabove may be mounted on a frame 54 of a
housing 55, as shown in FIG. 3.
[0067] FIG. 5 is an ABS view of the slider 42 and the magnetic head
40. The slider has a center rail 56 that supports the magnetic head
40, and side rails 58 and 60. The rails 56, 58 and 60 extend from a
cross rail 62. With respect to rotation of the magnetic disk 34,
the cross rail 62 is at a leading edge 64 of the slider and the
magnetic head 40 is at a trailing edge 66 of the slider.
[0068] FIG. 6 is a side cross-sectional elevation view of the
merged MR head 40, which includes a write head portion 70 and a
read head portion 72, the read head portion employing a sensor 74.
FIG. 7 is an ABS view of FIG. 6. The sensor 74 is sandwiched
between first and second gap layers 76 and 78, and the gap layers
are sandwiched between first and second shield layers 80 and 82. In
response to external magnetic fields, the resistance of the sensor
74 changes. A sense current I.sub.S conducted through the sensor
causes these resistance changes to be manifested as potential
changes. These potential changes are then processed as readback
signals by the processing circuitry 50 shown in FIG. 3.
[0069] The write head portion of the merged MR head includes a coil
layer 84 sandwiched between first and second insulation layers 86
and 88. A third insulation layer 90 may be employed for planarizing
the head to eliminate ripples in the second insulation layer caused
by the coil layer 84. The first, second and third insulation layers
are referred to in the art as an "insulation stack". The coil layer
84 and the first, second and third insulation layers 86, 88 and 90
are sandwiched between first and second pole piece layers 92 and
94. The first and second pole piece layers 92 and 94 are
magnetically coupled at a back gap 96 and have first and second
pole tips 98 and 100 which are separated by a write gap layer 102
at the ABS. As shown in FIGS. 2 and 4, first and second solder
connections 104 and 106 connect leads from the spin valve sensor 74
to leads 112 and 114 on the suspension 44, and third and fourth
solder connections 116 and 118 connect leads 120 and 122 from the
coil 84 (see FIG. 8) to leads 124 and 126 on the suspension.
First Embodiment of the Invention
[0070] The first embodiment 200 of the present invention is shown
in FIGS. 9 and 10. The first embodiment of the write head includes
a first pole piece (P1) 202 which has a pedestal portion 204 at the
ABS and a recessed portion 206 which may extend from the pedestal
portion to and beyond the back gap (BG). The pedestal portion 204
and the recessed portion 206 provide a recess wherein recessed
insulation material 208 is located and is planar with a top surface
of the pedestal portion 204. A preferred material for the recessed
insulation material is aluminum oxide (Al.sub.2O.sub.3). A write
gap layer 210 is located on the pedestal portion 204 in the pole
tip region and may extend from the pole tip region to and past the
back gap (BG) if desired. A second pole tip (P2) 212 is located on
the write gap layer 210 and forms a portion of the ABS. A write
coil layer 214 is located on the write gap layer 210 in the yoke
region of the head and winds around the back gap (BG). A write coil
insulation layer 216 is located between turns of the coil layer 214
and between the coil layer and the second pole tip 212. The top
surfaces of the second pole tip layer 212, the coil layer 214 and
the write coil insulation layer 216 form a common flat surface. A
top insulation layer 220 insulates the top surface of the coil
layer 214.
[0071] A yoke portion of the second pole piece (P2 yoke) 222 is on
the top insulation layer 220 and is magnetically connected to the
second pole tip 212 in the pole tip region and is magnetically
connected to the first pole piece 206 at the back gap (BG). The
recessed insulation layer 208, the write gap layer 210 and the top
insulation layer 220 are preferably aluminum oxide
(Al.sub.2O.sub.3) and the write coil insulation layer 216 is
preferably silicon dioxide (SiO.sub.2). It can be seen from this
construction that the yoke portion 222 of the second pole piece is
substantially planar except for the minor step of the top
insulation layer 220. The top insulation layer 220, however, can be
very thin, in the order of 1,000 .ANG. to 2,000 .ANG.. Essentially,
the yoke portion 222 of the second pole piece is substantially flat
so as to prevent a curve over an insulation stack which is shown by
the second pole piece layer 94 in FIG. 6.
[0072] The silicon dioxide (SiO.sub.2) material of the write coil
insulation layer 216 has a coefficient of expansion close to the
coefficient of expansion of the overcoat layer 224 which covers the
write head. Accordingly, upon expansion due to heat the write coil
insulation layer 216 will not force the overcoat layer 224 beyond
the ABS which is a potential problem caused by the insulation stack
comprising layers 86, 88 and 90 in FIG. 6.
[0073] Below the write head is a read head which includes a first
shield layer 230 and a second shield layer. In a merged head the
second shield layer may comprise the first pole piece 202 of the
write head. First and second read gap layers 232 and 234 are
located between the first and second shield layers 230 and 202 and
a read sensor 236 is located between the first and second read gap
layers 232 and 234. When the layer 202 is employed as the first
pole piece for the write head and a second shield layer for the
read head, the combined head structure is referred to as a merged
head. When these layers are separate the combined head is referred
to as a piggyback head.
[0074] It should be noted that the write coil insulation layer 216
may also be located between turns of the coil layer behind the back
gap (BG). FIG. 10 shows an ABS illustration of FIG. 9 where the
side walls 240 and 242 of the second pole tip 212 are highly
defined because the write head is planar behind the second pole tip
212. Accordingly, patterned photoresist employed for constructing
the second pole tip 212 will not receive reflective light from the
high topography of an insulation stack, as shown in FIG. 6, during
the light exposure step of the photoresist. Further, the overcoat
layer 224 can be made thin because it does not have to account for
the high topography caused by the insulation stack in FIG. 6.
Second Embodiment of the Present Invention
[0075] FIGS. 11 and 12 show a second embodiment 250 of the present
write head. The write head 250 includes a first pole piece 252
which is planar from the ABS to and past the back gap (BG). The
write gap layer 254 is located on the first pole piece 252 from the
ABS to at least the back gap (BG). The write gap layer 254 serves
as an etch step in this embodiment, which will be described in
detail under the method of construction of the second embodiment. A
second pole tip layer 256 is located on the write gap layer 254 in
the pole tip region and a write coil layer 258 is located on the
write gap layer 254 in the yoke region. A write coil insulation
layer 260 is located between the turns of the write coil 258 and
between the write coil and the second pole tip layer 256. Top
surfaces of the second pole tip 256, the write coil layer 258, and
the write coil insulation layer 260 form a common flat surface. The
top insulation layer 262 is located on the top flat surface and
insulates the top surface of the coil layer 258.
[0076] A yoke portion 264 of a second pole piece is located on the
top insulation layer 262 and is magnetically connected to the
second pole tip layer at 264 and is magnetically connected to the
first pole piece 252 at the back gap (BG). It should be noted in
this embodiment that the write coil layer 254 is the only layer
insulating the coil layer 258 from the first pole piece 252.
Accordingly, the first pole piece 252 of the embodiment in FIG. 11
will have greater flux carrying capability than the first pole
piece of the embodiment shown in FIG. 9.
[0077] The definition of the side walls 270 and 272 of the second
pole tip layer 256, shown in FIG. 12, are well-defined in the same
manner as the side walls 240 and 242, shown in FIG. 10. Further,
the yoke portion 264 of the second pole piece is substantially flat
in the same manner as the yoke portion 222 of the second pole piece
in FIG. 9. Again, the write gap layer 254 and the top insulation
layer 262 are preferably aluminum oxide (Al.sub.2O.sub.3) and the
write coil insulation layer is preferably silicon dioxide
(SiO.sub.2). The read head below this write head is the same as the
read head shown in FIG. 9.
Method of Making First Embodiment
[0078] A method of making the first write head embodiment shown in
FIGS. 9 and 10 is shown in FIGS. 13-28. In FIG. 13 a first pole
piece material layer 300 is formed by any suitable means such as
photopatterning with photoresist and plating. The first pole piece
material layer 300 may be formed on the second read gap layer 234
shown in FIG. 9. The left side of the first pole piece material
layer 300 is an air bearing surface (ABS) site which is formed
after all of the heads are completed on a wafer and diced into rows
of heads. Accordingly, the first pole piece material layer 300
actually covers an entire wafer and then is subsequently processed,
which will be described next.
[0079] In FIG. 14 the first pole piece layer 300 in FIG. 13 has
been photopatterned and plated to provide a first pole piece 302
that has a pedestal portion 304 in a pole tip region and a recessed
portion 306 which extends through the yoke region to at least the
back gap (BG).
[0080] In FIG. 15 a recessed insulation material layer 308 is
deposited by any suitable means such as sputtering, which covers
the pedestal 304 and the recessed portion 306 of the first pole
piece. It is important that the thickness of the recessed
insulation layer 308 be thicker and the height of the pedestal 304
above the recessed portion 306. In FIG. 16 the wafer is chemically
mechanically polished (CMP) which forms the recessed insulation
layer 310 with a top surface 312 that is planar with a top surface
314 of the pedestal portion 304 of the first pole piece. In FIG. 17
a write gap layer 316 is formed on the top surface of the pedestal
portion 304 of the first pole piece layer. It is preferred that the
write gap layer 316 also cover the recessed insulation layer 310 so
as to eliminate a masking step. In FIG. 18 a second pole tip layer
318 is formed on the write gap layer 316 in the pole tip
region.
[0081] In FIG. 19 a write coil insulation material layer 320 is
formed on the second pole tip layer 318 and on the write gap layer
316. It is important that the thickness of the layer 320 be thicker
than the thickness of the second pole tip layer 318, which will be
explained in more detail hereinafter. In FIG. 20 a photoresist
material layer has been spun on the head and patterned to provide a
patterned photoresist layer 322 on the write coil insulation
material layer 320 with a spiral-shaped opening 324 which exposes a
portion of the top surface of the write coil insulation material
layer 320 where a write coil is to be formed. Alternatively, an
inorganic insulation material layer, such as Al.sub.2O.sub.3 or
NiFe can be prepared for reactive ion etching (RIE) image transfer
and then subsequently removed by chemical mechanical polishing
(CMP). A preferable material for the write coil insulation material
layer 320 is silicon dioxide (SiO.sub.2), which is a material which
can be etched by reactive ion etching (RIE) with a fluorine base
such as CF.sub.4, CHF.sub.3, C.sub.2F.sub.6 or SF.sub.6. In FIG. 21
the reactive ion etch (RIE) etches openings 326 in the write coil
insulation material layer 320 where a write coil is to be formed.
It should be noted that the reactive ion etching (RIE) is stopped
at the gap layer 316 or at the recessed insulation layer 308 if the
write gap layer is omitted from the yoke region. The gap layer 316
and the recessed insulation layer 308 are preferably aluminum oxide
(Al.sub.2O.sub.3) which is not etched significantly by the
fluorine-based RIE. Accordingly, when silicon dioxide (SiO.sub.2)
is employed for the write coil insulation material layer 320 and
aluminum oxide (Al.sub.2O.sub.3) is employed for the write gap
layer 316 or the insulation layer 308 the fluorine-based reactive
ion etch is selective to the write coil insulation material layer
320.
[0082] In FIG. 23 a seed layer has been sputter deposited followed
by formation of a write coil material layer 328 by any suitable
means such as plating or sputter deposition. It is important that
the thickness of this layer be thicker than the height of the
second pole tip 318. In FIG. 24 the wafer is chemically
mechanically polished (CMP) which forms a write coil layer 330 and
the previously mentioned write coil insulation material layer 320
into a write coil insulation layer 332 which is located between the
turns of the coil and between the coil layer 330 and the second
pole tip 318. Top surfaces of the second pole tip 318, the coil
layer 330 and the write coil insulation layer 332 form a common
flat surface. This is important for subsequent construction of the
second pole piece.
[0083] In FIG. 25 a top insulation layer 334 is formed on top of
the top surface of the coil layer 330 by any suitable means such as
photopatterning with photoresist and sputter deposition of aluminum
oxide (Al.sub.2O.sub.3) followed by a lift off process. In FIG. 26
the wafer is photopatterned with patterned photoresist 336 that has
an opening 338 where a back gap (BG) is to be formed. The wafer is
then etched to etch through the write coil insulation layer 332,
the write gap layer 316 and the recessed insulation layer 310 to
expose the first pole piece in the back gap region. In FIG. 27 the
yoke portion 340 of the second pole piece is formed on top of the
top insulation layer 334 with a magnetic connection with the second
pole tip 318 at 342 and a connection with the first pole piece at
344 in the back gap region.
[0084] FIG. 28 is an ABS illustration of FIG. 27 after formation of
an overcoat layer 346. The material of the overcoat layer is
preferably aluminum oxide (Al.sub.2O.sub.3). After construction of
rows and columns of heads on a wafer, the wafer is diced into rows
of heads and lapped to form the air bearing surface (ABS) as shown
in FIG. 29. The rows and heads are then diced into separate heads
and mounted on a disk drive for operation.
Method of Construction of the Second Embodiment of the Write
Head
[0085] FIGS. 30-42 illustrate the method of constructing the second
embodiment of the write head shown in FIGS. 11 and 12. In FIG. 30 a
first pole piece layer 400 is constructed on the second read gap
layer 234 shown in FIG. 11. The first pole piece layer 400 extends
from an ABS site to at least the back gap region. In FIG. 31 a
write gap layer 416 is formed on the first pole piece layer 400
from the ABS site to at least to the back gap region. The write gap
layer may be formed by any suitable means such as sputter
deposition and is preferably aluminum oxide (Al.sub.2O.sub.3). In
FIG. 32 a second pole tip layer 418 is formed on the write gap
layer 416 in the pole tip region.
[0086] In FIG. 33 a write coil insulation material layer 420 is
formed on the second pole tip layer 418 and on the write gap layer
416. It is important that the thickness of the layer 420 be thicker
than the thickness of the second pole tip layer 418, which will be
explained in more detail hereinafter. In FIG. 34 a photoresist
material layer has been spun on the head and patterned to provide a
patterned photoresist layer 422 on the write coil insulation
material layer 420 with a spiral-shaped opening 424 which exposes a
portion of the top surface of the write coil insulation material
layer 420 where a write coil is to be formed. A preferred material
for the write coil insulation material layer 420 is silicon dioxide
(SiO.sub.2) which is a material which can be etched by reactive ion
etching (RIE) with a fluorine base such as CF.sub.4, CHF.sub.3,
C.sub.2F.sub.6 or SF.sub.6. In FIG. 35 the reactive ion etch (RIE)
etches openings 426 in the write coil insulation material layer 420
where a write coil is to be formed. It should be noted that the
reactive ion etching (RIE) is stopped at the gap layer 416. The gap
layer 416 is preferably aluminum oxide (Al.sub.2O.sub.3) which is
not etched by the fluorine-based RIE. Accordingly, when silicon
dioxide (SiO.sub.2) is employed for the write coil insulation
material layer 420 and aluminum oxide (Al.sub.2O.sub.3) is employed
for the write gap layer 416 the fluorine-based reactive ion etch is
selective to the write coil insulation material layer 420 with
respect to the write gap layer 416. Accordingly, the write gap
layer 416 provides an etch stop so that the reactive ion etch (RIE)
sell not etch into the first pole piece layer 400. Further, the
write gap layer 416 will serve as the only insulation layer between
the first pole piece 400 and a write head to be subsequently
constructed.
[0087] In FIG. 37 a seed layer has been sputter deposited followed
by formation of a write coil material layer 428 by any suitable
means such as plating or sputter deposition. It is important that
the thickness of this layer be thicker than the height of the
second pole tip 418. In FIG. 38 the wafer is chemically
mechanically polished (CMP) which forms a write coil layer 430 and
the previously mentioned write coil insulation material layer 420
into a write coil insulation layer 432 which is located between the
turns of the coil and between the coil layer 430 and the second
pole tip 418. Top surfaces of the second pole tip 418, the coil
layer 430 and the write coil insulation layer 432 form a common
flat surface. This is important for subsequent construction of the
second pole piece.
[0088] In FIG. 39 a top insulation layer 434 is formed on top of
the top surface of the coil layer 430 by any suitable means such as
photopatterning with photoresist and sputter deposition of aluminum
oxide (Al.sub.2O.sub.3). In FIG. 40 the wafer is photopatterned
with patterned photoresist 436 that has an opening 438 where a back
gap (BG) is to be formed. The wafer is then etched to etch through
the write coil insulation layer 432 and the write gap layer 416 to
expose the first pole piece in the back gap region. In FIG. 41 the
yoke portion 440 of the second pole piece is formed on top of the
top insulation layer 434 making a magnetic connection with the
second pole tip 418 at 442 and making a magnetic connection with
the first pole piece at 444 in the back gap region.
[0089] FIG. 42 is an ABS illustration of FIG. 41 after formation of
an overcoat layer 446. The material of the overcoat layer is
preferably aluminum oxide (Al.sub.2O.sub.3). After construction of
rows and columns of heads on a wafer, the wafer is diced into rows
of heads and lapped to form the air bearing surface (ABS) as shown
in FIG. 29. The rows and heads are then diced into separate heads
and mounted on a disk drive for operation.
[0090] Clearly, other embodiments and modifications of this
invention will occur readily to those of ordinary skill in the art
in view of these teachings. For instance, in a broad aspect of the
invention the second pole piece in FIG. 11 may be stitched, as
shown, or non-stitched wherein the top surfaces of the coil layer
and the non-organic intercoil layer 260 are coplanar. Therefore,
this invention is to be limited only by following claims, which
include all such embodiments and modifications when viewed in
conjunction with the above specification and accompanying
drawings.
* * * * *