U.S. patent application number 10/243271 was filed with the patent office on 2004-03-18 for thin film head reader with lead overlay a method of fabrication thereof.
This patent application is currently assigned to International Business Machines Corporation. Invention is credited to Lee, Edward Hin Pong, Lee, Kim Y., Lin, Tsann, Wang, Chun-Ming, Zolla, Howard Gordon.
Application Number | 20040052005 10/243271 |
Document ID | / |
Family ID | 31991593 |
Filed Date | 2004-03-18 |
United States Patent
Application |
20040052005 |
Kind Code |
A1 |
Zolla, Howard Gordon ; et
al. |
March 18, 2004 |
Thin film head reader with lead overlay a method of fabrication
thereof
Abstract
A magnetoresistive sensor having a well defined track width and
method of manufacture thereof.
Inventors: |
Zolla, Howard Gordon; (San
Jose, CA) ; Lee, Edward Hin Pong; (San Jose, CA)
; Lee, Kim Y.; (Fremont, CA) ; Lin, Tsann;
(Saratoga, CA) ; Wang, Chun-Ming; (San Jose,
CA) |
Correspondence
Address: |
IBM Corporation
Intellectual Property Law
5600 Cottle Road (L2PA/0142)
San Jose
CA
95193
US
|
Assignee: |
International Business Machines
Corporation
Armonk
NY
|
Family ID: |
31991593 |
Appl. No.: |
10/243271 |
Filed: |
September 12, 2002 |
Current U.S.
Class: |
360/322 ;
29/603.07; G9B/5.114 |
Current CPC
Class: |
Y10T 29/49043 20150115;
G11B 5/313 20130101; Y10T 29/49032 20150115; Y10T 29/49046
20150115; G11B 5/3163 20130101; Y10T 29/49048 20150115; G11B 5/3909
20130101; G11B 5/3116 20130101; B82Y 25/00 20130101; G11B 5/3903
20130101; G11B 2005/3996 20130101; Y10T 29/49052 20150115; B82Y
10/00 20130101 |
Class at
Publication: |
360/322 ;
029/603.07 |
International
Class: |
G11B 005/39 |
Claims
What is claimed is:
1. A magnetic head, comprising: a magnetoresistive layer, having a
central active region and first and second laterally opposed end
regions terminating in first and second sides; first and second
electrically conductive pads overlaying said magnetoresistive layer
at said first and second end regions and terminating at said first
and second sides; first and second hard bias layers contacting said
first and second sides; and first and second electrically
conductive lead layers overlaying at least a portion of said first
and second electrically conductive pads.
2. A magnetic head as set forth in claim 1 and wherein said and
first and second electrically conductive pads comprise Rh.
3. A magnetic head as set forth in claim 1 wherein the first and
second lead layers comprise Rh.
4 A magnetic head as set forth in claim 1 wherein said
magnetoresistive sensor has a substantially flat surface that is
bounded by said first and second laterally opposed sides and
wherein said first and second electrically conductive pads prevent
said first and second hard bias layers from contacting said
substantially flat surface.
5. A magnetic head, comprising, a magnetoresistive element having a
substantially flat surface and laterally opposed first and second
side portions; said first and second side portions joining said
flat surface to form first and second edges; first and second
electrically conductive pads contacting said substantially flat
surface and terminating at said first and second edges
respectively; and first and second hard magnetic biasing layers
disposed adjacent to said first and second side portions.
6. A magnetic head as recited in claim 6 wherein said first and
second electrically conductive pads prevent contact between said
first and second hard magnetic biasing layers and said
substantially flat surface.
7. A magnetic sensor as set forth in claim 5 further comprising
first and second electrically conductive leads contacting said
first and second electrically conductive pads.
8. A magnetic sensor as set forth in claim 7 wherein said first and
second electrically conductive pads are relatively thin as compared
with said first and second electrically conductive lead.
9. A method of constructing a magnetic sensor, comprising the steps
of: depositing a layer of magnetoresistive sensor material; forming
a first electrically conductive layer having a gap, the width of
said gap defining a track width; depositing a mask layer, said mask
layer shielding said gap and a portion of said electrically
conductive layer adjacent to said gap; and performing a material
removal process to remove exposed portions of said electrically
conductive layer and said magnetoresistive sensor material.
10. A method as recited in claim 9 further comprising the step of,
depositing a layer of magnetic material prior to removing said
mask.
11. A method as recited in claim 9 wherein said material removal
process is reactive on etching.
12. A method as recited in claim 9 wherein said material removal
process is ion milling.
13. A method of manufacturing a magnetic head, comprising:
providing a substrate; depositing a magnetoresistive material
layer; forming a first mask on the magnetoresistive material layer;
depositing a first electrically conductive material; removing said
first mask; forming a second mask, the second mask being wider than
the first mask; performing a material removal procedure to remove
material not protected by said second mask; depositing a hard
magnetic material; depositing a second electrically conductive
material; and removing said second mask.
14. A method of manufacturing a magnetic head, comprising:
providing a substrate; depositing a magnetoresistive material onto
said substrate; depositing a first electrically conductive
material; forming a first mask on said first electrically
conductive material, said mask having an opening to expose a
portion of said first electrically conductive material; performing
a first material removal process to remove electrically conductive
material exposed by said mask to form a gap in said electrically
conductive material; removing said first mask; forming a second
mask, the second mask being wider than said first mask; performing
a second material removal process to remove material not protected
by said second mask; depositing a hard magnetic material;
depositing a second electrically conductive material; and removing
said second mask.
15. A magnetic disk drive, comprising: a chassis; motor coupled
with said chassis; spindle rotateably coupled with said motor; a
disk coupled with said spindle for rotation thereabout; an actuator
pivotally coupled with said chassis; a slider coupled with an end
of said actuator for arcuate movement across a surface of said
disk; a magnetic write element coupled with said slider; and a
magnetic read element coupled with said slider, said read element
further comprising: a magnetoresistive layer, having a central
active region and first and second laterally opposed end regions
terminating in first and second sides; first and second
electrically conductive pads overlaying said magnetoresitive layer
at said first and second end regions and terminating at said first
and second sides; first and second hard bias layers contacting said
first and second sides; and first and second electrically
conductive lead layers overlaying at least a portion of said first
and second electrically conductive pads.
16. A magnetic head as recited in claim 1 wherein said first and
second electrically conductive pads are 20-30 manometers.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to magnetoresistive sensors
and more particularly to a lead overlay sensor design that provides
width size and improved trackwidth control.
[0003] 2. Description of the Related Art
[0004] Digital memory lies at the heart of all computer systems.
Magnetic Disk Drives provide the this memory function in most
modern computers systems, due to their ability to inexpensively
store large amounts of data in such a manner that the data can be
immediately, randomly retrieved. A magnetic disk drive includes one
or more rotating magnetic disks, magnetic 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.
When the disk rotates, viscous forces in the air cause the air
immediately adjacent to the disk to move with the disk. The ABS is
aerodynamically configured to allow the slider to fly upon this
moving air immediately adjacent to the disk surface.
[0005] As the disk moves past the slider, the write head emits
magnetic flux pulses in order to imprint a magnetic signal onto the
disk. These magnetic signals can then be read by the read head by
moving the slider over a desired track and reading the magnetic
signal as it moves past the read head.
[0006] Various magnetic sensors have been used to read data from a
magnetic medium. Some prior art disk drives have used anisotropic
magnetoresistive (AMR) sensors, while more recently disk drive
devices have employed giant magnetoresistive sensors (GMR) also
known as spin valves. Various other sensors have been proposed as
well, such as tunneling magnetoresistive sensors (TMR). At present,
GMR sensors are by far the most widely used and as such will be
described in more detail herein. GMR sensors operate on what has
been called the "spin valve effect", and includes a non-magnetic
conductive spacer material sandwiched between layers of magnetic
material. The layer at one side of the side of the spacer material
has a magnetic moment that is pinned in a given direction, this
layer is generally referred to as the pinned layer. The magnetic
material at the other side of the spacer layer has a magnetization
that is biased perpendicular to that of the pinned layer, but is
free to rotate in the presence of a magnetic field. This layer is
generally referred to as the free layer. The selective spin
scattering of electrons passing through the sensor causes the
electrical resistance of the sensor to change as the angle of the
magnetization of the free layer relative to that of the pinned
layer changes. In this way, as the moves passed a magnetic field
produced by the passing magnetic disk, the angle of the free layer
magnetization changes, thereby changing the resistance of the
sensor. This change in resistance is detected by passing a sense
current through the sensor and detecting the voltage change across
the sensor.
[0007] The computer industry constantly requires larger memory
storage capacity in ever smaller devices. One way to increase data
storage efficiency is to reduce the width of a track of data. The
reduction of track width allows more tracks of data to be stored on
a single disk. One attempt to minimize track width can be more
readily understood with reference to FIG. 1 which describes a read
sensor 10 having a lead overlay design. The sensor 10 is built upon
a gap layer 12, which is an electrically insulating, non-magnetic
material. An antiferromagnetic material 14 is formed over the gap
layer and is used to fix the magnetization of a magnetically pinned
layer 16, in a manner which will be familiar to those skilled in
the art. An electrically conductive, non-magnetic spacer layer 18
is formed over the pinned layer, and a magnetically free layer 20
is formed over the spacer layer 18 at the side opposite the pinned
layer. Hard bias layers 24 are formed at either side of the sensor
10. The hard bias layers are constructed of a material having a
high magnetic moment when magnetized acts to bias the magnetization
of the free layer in a desired direction due to magnetostatic
forces between the hard bias material 24 and the free layer 20. In
the lead overlay design described herein, electrical leads 26 are
formed over the top of the sensor 10 at portions of the sensor. The
leads 26 provide the sense current to the sensor, and as will be
appreciate by those skilled in the art, the track width TW of such
a design is defined as the distance between the leads. Prior art
lead overlay designs and methods of manufacture make accurate track
width definitions somewhat difficult as will be described in
greater detail below in a discussion of the prior art methods of
making such lead overlay sensor.
[0008] With continued reference to FIG. 1, the hard bias material
22 tends to slightly overlap the free layer 20, resulting in what
has been called a "birds beak" 26. Such a birds beak 26 is
undesirable because it results in magnetic instability in the free
layer.
[0009] With reference to FIGS. 2 through 4 an exemplary method of
manufacturing such a lead overlay sensor 10 will be described. With
reference to FIG. 2, a layer of sensor materials 28 is formed over
the gap material 12. The layer of sensor material could include the
various layer making up the sensor 10 as described with reference
to FIG. 1 or could be layers making up some other type of sensor
such as ARM, TMR etc. A first mask 30, which could be a bi-layer
photoresist mask is formed over the sensor layer 28 and is formed
of such a width as to define the edges of the sensor. An ion
milling process indicated by arrows 32 is used to remove sensor
material not protected by the mask 30. This process is generally
referred to in the industry as the K2 milling process, or just K2.
After the ion milling process 32 has been completed, the hard bias
layers 22 are deposited, using the same mask 30 that was used to
define the edges of the sensor 10. As can be seen with reference to
FIG. 3, this method of construction allows the hard bias layers 22
to slightly overlap the sensor 10. After the hard bias 22 has been
deposited, the first mask 30 is removed. The first mask 30 is
replaced with a second mask 34, which is narrower than the first
mask, and can also be constructed as a bi-layer photoresist
structure. As will be seen, this second mask defines the track
width dimension. With the second mask 34 in place, the lead
material is deposited. As can be seen with reference to FIG. 4,
since the second mask 34 is narrower, than the first mask 30, the
lead material can be deposited directly onto the sensor at side
portions of the sensor extending inward from the inner edges of the
hard bias material 22. This step forming the second mask 34 and
forming the leads 24 is referred to in the industry as "K5". With
the lead layer formed, the second mask layer 34 can be removed and
a cap layer (not shown) can be deposited to protect the sensor from
subsequent manufacturing process that will be familiar to those
skilled in the art.
[0010] As will be appreciated from the above, the track width is
defined by the second mask 34. However, as can be seen, this
critical photolithographic step is performed on a surface having a
severe topography rather than on planar surface as would be
desired. This makes accurate photolithography difficult, and as a
result makes accurate definition of the track width difficult. In
addition, the thickness with which the leads can be deposited is
limited, because depositing too much lead material would completely
cover the resist structure 34 making it impossible to remove.
[0011] From the above it will be appreciated that there remains a
need for a magnetic sensor design that provides for very accurate
track width definition, while utilizing presently implemented
manufacturing techniques. There also remains a need for a lead
overlay design, and method of manufacture, that will minimize the
effects of hard bias birds beaks.
SUMMARY OF THE INVENTION
[0012] The present invention provides a mangnetoresistive sensor
having a well defined track width. The sensor of the present
invention includes a layer of magnetoresistive sensor material
having a central active region and end regions at opposite ends of
the sensor. The end regions terminate at first and second portions
of the sensor. First and second electrically conductive pads are
formed on each of the end regions and terminate at the first and
second sides. First and second hard bias layers are formed at the
first and second sides of the sensor material, and first and second
lead layers are formed over at least a portion of the first and
second electrically conductive pads, and the first and second hard
bias material.
[0013] The present invention can be formed by a method wherein, a
layer of electrically conductive material is deposited over a full
film of sensor material, with a first photolithographic process
being employed to form a gap in the electrically conducive
material. Thereafter, a second photolithographic process may be
employed to selectively remove lead material and sensor material to
define a sensor having opposite sides. The photolithographic
process used to define the sensor, may use a photoresist mask
having a width that is essentially the same as the desired width of
the sensor. This same mask may also be used to form first and
second hard bias layers at the sides of the sensor, and to form
electrically leads contacting the hard bias material and at least a
portion of the earlier deposited electrically conductive material.
The layer of lead material deposited in this last lithographic step
may be significantly thicker than the layer of electrically
conductive material deposited in the first lithographic step.
[0014] The first photolithographic step forms the gap in the first
deposited electrically conductive material thereby defines the
track width of the invention. Advantageously, this
photolithographic step is performed on a planar surface and as such
can be performed very accurately, allowing the sensor to be
constructed with a smaller, more controllable trackwidth.
Furthermore, the electrically conductive material deposited in
conjunction with the first lithographic process can be deposited
very thin. This allows a thinner mask to be used in the first
photolithographic step, further facilitating narrower, more
controllable trackwidth definition.
[0015] After the second photolithographic procedures has defined
the sides of the sensor, the sensor could be described as having a
flat upper surface terminating at first and second edges with
laterally opposed sensor sides extending downwardly from the edges.
The sensor sides may be sloped at an angle. The first layer
electrically conductive material at this point may be described as
first and second thin lead pads formed on the flat upper surface of
the sensor at opposite end regions of the sensor. The region
between these thin lead pads may be described as the central,
active region of the sensor, and defines the trackwidth of the
sensor.
[0016] Hard bias material layers may be formed to extend from and
contact the side of the sensor, and may or may not slightly overlap
the thin lead layers. It is an advantage of the present invention,
the that the thin lead layers deposited onto the sensor prevent the
hard bias material from contacting the flat upper surface of the
sensor and thereby limit contact to only the sides of the sensor.
Contact between the hard bias layers and the upper surface of the
sensor (known in the art as a "birds beak") results in magnetic
instability of the sensor, by interfering with the magnetic
properties of the free layer of the sensor.
[0017] With the hard bias material deposited, another layer of
electrical material may be deposited onto at least a portion of the
first and second thin lead pads and onto at least a portion of the
hard bias material. This second layer of lead material may be
significantly thicker than the layer used to form the first and
second pads, and is deposited by a photolithographic process
resulting in lead portions that contact the electrically conductive
pads and extend laterally outwardly from the sensor. It will be
appreciated the photolithographic process used to define the
thicker, later applied lead material is much less critical than
that of the first two lithographic processes which defined the
track width and the sensor width. It is an advantage of the
invention that this less critical photolithographic step is
conducted on a non-planar surface, while the more critical track
width defining photolithography is performed on a planar
surface.
[0018] Another advantage of the present invention is that by using
a thin layer of lead material, the track width defining inner edge
of the thin lead pads can be formed with a well defined edge rather
than a loosely defined tapered edge.
[0019] These and other aspects and advantages of the present
invention will be better appreciate upon reading the following
description taken together with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a cross sectional view, not to scale, of a prior
art lead overlay read sensor;
[0021] FIG. 2 is a cross sectional view, not to scale of a step in
a prior art process of making a read sensor;
[0022] FIG. 3 is a cross sectional view, not to scale of a step in
a prior art process of making a read sensor;
[0023] FIG. 4 is a cross sectional view, not to scale of a step in
a prior art process of making a read sensor;
[0024] FIG. 5 is a plan view, not to scale, of a disk drive
incorporating magnetic head according to the present invention;
[0025] FIG. 6 is a profile view, not to scale, taken along line 6-6
or FIG. 5;
[0026] FIG. 7 is an end view of a slider, not to scale, taken along
line 7-7 of FIG. 5;
[0027] FIG. 8 is a sectional view of a a read head, not to scale
and shown enlarged, taken along line 8-8 of FIG. 7;
[0028] FIG. 9 is a sectional view, not to scale, depicting a step
in a process of manufacturing a magnetic head according to the
present invention;
[0029] FIG. 10 is a sectional view, not to scale, depicting a step
in a process of manufacturing a magnetic head according to the
present invention;
[0030] FIG. 11 is a sectional view, not to scale, depicting a step
in a process of manufacturing a magnetic head according to the
present invention;
[0031] FIG. 12 is a sectional view, not to scale, depicting a step
in a process of manufacturing a magnetic head according to the
present invention;
[0032] FIG. 13 is a sectional view, not to scale, depicting a step
in a process of manufacturing a magnetic head according to the
present invention;
[0033] FIG. 14 is a flow chart illustrating steps in method of
manufacturing a magnetic head according to the present
invention;
[0034] FIG. 15 is a sectional view, not to scale, depicting a step
in an alternate method of manufacturing a magnetic head according
to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] Referring now to the drawings, wherein like reference
numerals designate like or similar parts throughout the several
views, FIGS. 5-7 illustrate a magnetic disk drive 100. The drive
100 includes a spindle 102 that supports and rotates one or more
magnetic disks 104. The spindle 102 is rotated by a motor 106 that
is controlled by a motor controller 108. A combined read and write
magnetic head 110 is mounted on a slider 112 that is supported by a
suspension 114 and actuator arm 116. A plurality of disks, sliders
and suspensions may be employed in a large capacity direct access
storage device (DASD) as shown in FIG. 6. The suspension 114 and
actuator arm 116 position the slider 112 so that the magnetic head
110 is in a transducing relationship with a surface of the magnetic
disk 104. When the disk 104 is rotated by the motor 106, the slider
is supported on a thin cushion of air (air bearing) between the
surface of the disk 104 and an air bearing surface (ABS) 118. The
magnetic head 110 may then be employed for writing information to
multiple circular tracks on the surface of the disk 104, as well as
for reading information therefrom. Processing circuitry 120
exchanges signals representing such information with the head 110,
provides motor drive signals for rotating the magnetic disk 104,
and provides control signals for moving the slider to various
tracks. The various components making up the disk drive can be
mounted on or within a chassis 122.
[0036] With reference now to FIG. 8, a cross sectional view, not to
scale, as viewed from the ABS is depicted. Those skilled in the art
will appreciate that such a magnetic head would also include a
write head and first and second shields. However, for purposes of
clarity only the read sensor and its associated leads are depicted.
The read head includes a magnetoresistive sensor 126, which may be
a GMR sensor as described with reference to the background art or
could also be some other type of magnetoresistive sensor, such as
TMR or AMR. The sensor 126 has a substantially flat surface 128
terminating first and second laterally opposed edges 130, 132. The
sensor 126 also has first and second sides 134, 136, which extend
from the edges 130, 132 and slope downward to the substrate
supporting the sensor 126. The substrate is preferably a
non-magnetic electrically insulting gap layer 12 as described with
reference to the background art and will hereafter simply be
referred to as the substrate 12. It will be appreciated that while
the sides 134, 136 are shown and described as sloping and having
portions that are somewhat straight, the sides could also be of
other configurations. For example, the sensor 126 could have
vertical or nearly vertical side walls or they could also have a
serpentine configuration or some other shape when viewed in cross
section as in FIG. 8.
[0037] With continued reference to FIG. 8, first and second thin
lead pads 138, 140 are formed on the substantially flat surface 128
of the sensor 126. The thin lead pads 138, 140 extend from inner
lead edges 142, 144 to the outer edges 130, 132 of the sensor 126.
The distance between the inner edges 142, 144 of the thin lead pads
138, 140 defines the track width TW of the read head 124. Because
the lead pads 138,140 are relatively thin, the inner edges 142, 144
can be formed to be well defined and accurately located. While the
lead pads could be constructed of various electrically conductive
materials, they are preferably Rh. Furthermore, the pads 138, 140
could be of various thicknesses, but are preferably 20-30 nm.
[0038] First and second hard bias layers 146, 148, deposited over
the substrate 12, extend over the sides 134, 136, and may also
extend over a portion of the thin lead layers 130, 132. With
reference to FIG. 8, it will be appreciated that the presence of
the thin lead layers 138, 140 prevents the hard bias layers from
contacting the flat surface of 128 of the sensor, ensuring that
only the side portions 136, 134 of the sensor 126 contact the hard
bias material 146, 148 and eliminating the "birds beak" problem
associated with the prior art. First and second electrically
conductive leads are formed over the hard bias material, and over a
portion of the thin lead pads 138, 140, and terminate at inner
edges 154, 156. Advantageously, the precise location of the inner
edges 154, 156 is not critical, however the inner edges 154, 156
somewhere along the top of the thin lead pads 138, 140, and
preferably somewhere near the center of the pads 138, 140. Like the
pads 138, 140, the leads 146, 148 preferably comprise Rh, although
they could be constructed of many electrically conductive
materials. The leads 146, 148 could be of various thicknesses, but
are preferably 60 to 80 nm, and more preferably are roughly 70 nm
thick.
[0039] With reference now to FIGS. 9 through 14, a method of
manufacturing a read head according to the present invention is
described. With particular reference to FIGS. 9 and 14, in a step
1402 a substrate is provided. This can be for example, the
electrically insulating, non-magnetic gap layer 12, which can
itself be formed upon another substrate, such as silicon. Then, in
a step 1404, a full film of magnetoresistive materials 158 is
deposited. Those skilled in the art will recognize that the full
film of magnetoresistive materials 158 is not a single film layer
but actually comprises the various material layers making up a
magneotresistive sensor such as the GMR sensor described with
reference to the prior art. The full film magnetoresistive
materials 158 could also comprise various material layers making up
some other type of magnetoresistive sensor, such as for example an
AMR or TMR sensor. After the sensor material 158 has been
deposited, in a step 1406, a photoresist mask 160 is formed in an
area to define the track width TW (FIG. 8) of the read head 124.
The photoresist layer is preferably a bi-layer photoresist, which
facilitates later lift off of the resist layer, but could also be
some other mask, such for example a single layer photoresist mask
or a mask made of a material other than photoresist. With the mask
160 in place, in a step 1408, a thin full film layer of
electrically conductive material 162 is deposited, preferably by
sputtering or some similar method. The mask 160 causes the
deposited electrically conductive film to define a gap 164 between
inner edges 142, 144. This layer of electrically conductive
material is deposited relatively thin as compared with the major
portion of the leads 152 (FIG. 8). This is advantageous in that it
prevents sealing off the photoresist mask 160, and allows a thinner
mask to be used. A thin mask structure provides more accurate
definition of the deposited material. The thin profile of the layer
162 allows it to be deposited evenly, with relatively abrupt, well
defined and accurately located inner edges 142, 144. Therefore, the
thin profile of the layer 162 allows the sensor 124 to be
constructed with a narrower, better controlled trackwidth. Another
important advantage of the present invention is that the
photolithographic, and deposition steps 1406, 1408 that define the
edges 142, 144 and gap 164 are performed on a completely planar
surface. Those skilled in the art will recognize such a flat
topography significantly improves the accuracy of the
photolithographic process used to construct the mask 160, further
facilitating the definition of narrower, better controlled
tackwidth. After the layer of electrically conductive material 162
has been deposited, in a step 1410, the mask 160 is lifted off
using methods familiar to those skilled in the art.
[0040] With reference now to FIGS. 10 and 14, in a step 1412, a
second mask layer 165 is formed. Like the first mask, this second
mask 165 can be formed as a bi-layer photoresist, by a
photolithographic process. This second mask is configured to be
wider than the first mask 160 (FIG. 9). The width of this second
mask 165 is chosen so as to define the width of the completed
sensor element 126 (FIG. 8), as will become apparent shortly. With
the mask 165 in place, in a step 1414, a material removal process
represented by arrows 166 is performed. This material removal
process is preferably an ion milling operation, but could be some
other procedure, such as for example reactive ion etching (RIE).
During the material removal procedure 1414 areas not protected by
the mask 165 are removed, resulting in a structure as depicted in
FIG. 11. The material removal procedure 1414 defines the sensor
element 126, having a flat upper surface 128 terminating in
laterally opposed side edges 130, 132 and having sides 134, 136.
The material removal procedure 1414 also completes the definition
of the thin lead pads 138, 140.
[0041] With reference now to FIGS. 12 and 14, in a step 1416 with
the second mask 165 still in place, a layer of hard magnetic
material 168 is deposited, the deposition process being represented
by vertical arrows 169. This produces the hard bias layers 146, 148
described earlier with reference to FIG. 8. Then, as described with
reference to FIGS. 13 and 14, in a step 1418, an electrically
conductive lead material 172 is deposited forming the leads 150,
152 described with reference to FIG. 8. As illustrated by the
diagonal arrows 171, the deposition of the lead material 172 is
performed at an angle. This allows the lead material to be
deposited further into the undercuts 174, 176 of the bi-layer
resist structure 165 with result that the deposited material 172
will be in electrical contact with the pads 138, 140. Because the
deposition process is performed in a sputtering chamber on a
rotating platter, the angled deposition will provide even
deposition with each of the undercuts 176, 174. Since the track
width TW of the sensor and the overall sensor width have already
been defined, the precise location of the endpoints 154, 156 is not
critical. This is advantageous in that the more critical
lithographic and deposition steps were performed on a planar
surface, leaving the less critical hard bias and lead depositions
169, 171 to be performed on the more severe topography of the
sensor 126. In a step 1420, the second mask layer 165 is lifted off
resulting in the read head described with reference to FIG. 8.
[0042] Various processes can be performed to complete construction
of a combination read/write head. Since these processes are
familiar to one skilled in the art they are omitted for purposes of
clarity. In addition various modifications will become apparent to
one skilled in the art which would still be contemplate by the
present invention. By way of example in an alternate method of
constructing such a read head 124 (FIG. 8) the gap 164 (FIG. 9) in
the thin electrically conductive material layer can be formed by a
material removal process. With reference to FIG. 15 a full film of
thin electrically conductive material 1502 can be deposited onto
the GMR material layer 158. Then a mask can be constructed to
expose the portions where the gap 164 is desired. A material
removal process, represented as arrows 1506 can then be performed
to selectively remove the exposed portions of the thin lead
material. The material removal process could be for example, but
not limited to reactive ion etching (RIE) or ion milling.
Furthermore, both the material used for the thin electrically
conductive layer and material removal process can be selected such
that the material removal process will selectively remove the thin
electrically conductive layer while reacting relatively little with
the underlying sensor materials 158.
[0043] Furthermore, should design requirement necessitate a larger
contact area between the leads 150, 152 and the pads 138, 140, an
alternate method of manufacture could be employed. In such an
alternate method, a third mask structure (not shown) could be
formed after formation of the hard bias layers 146, 148. This third
photo resist structure would then be wider than the first
photoresist structure, but narrower than the second. In such a
method of manufacture, the deposition of the lead material (also
not shown) may or may not be performed at an angle, depending upon
design requirements.
[0044] Other embodiments and modification of this invention will no
doubt occur to those of ordinary skill in the art in view of these
teachings. Therefore, this invention is to be limited only by the
following claims, which include all such embodiments and
modifications.
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