U.S. patent application number 15/161999 was filed with the patent office on 2017-11-23 for manufacturing method for a magnetic head including a main pole and a write shield.
This patent application is currently assigned to TDK CORPORATION. The applicant listed for this patent is TDK CORPORATION. Invention is credited to Hiroki ARITOMO, Michitaka NISHIYAMA, Koichi OTANI, Atsushi YAMAGUCHI, Yumiko YOKOYAMA.
Application Number | 20170337940 15/161999 |
Document ID | / |
Family ID | 60303354 |
Filed Date | 2017-11-23 |
United States Patent
Application |
20170337940 |
Kind Code |
A1 |
ARITOMO; Hiroki ; et
al. |
November 23, 2017 |
MANUFACTURING METHOD FOR A MAGNETIC HEAD INCLUDING A MAIN POLE AND
A WRITE SHIELD
Abstract
A manufacturing method for a magnetic head forms a leading
shield having a top surface. The top surface of the leading shield
includes first and second portions. The second portion is located
farther from a medium facing surface than is the first portion, and
recessed from the first portion. A first gap layer is then formed
on the first portion. Then, a magnetic layer including an initial
first side shield, an initial second side shield and a coupling
section connecting them is formed using a mold. The mold is then
removed. The coupling section is then removed by etching the
magnetic layer. A second gap layer and a main pole are then formed
in this order.
Inventors: |
ARITOMO; Hiroki; (Tokyo,
JP) ; YAMAGUCHI; Atsushi; (Tokyo, JP) ;
NISHIYAMA; Michitaka; (Tokyo, JP) ; YOKOYAMA;
Yumiko; (Tokyo, JP) ; OTANI; Koichi; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TDK CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
TDK CORPORATION
Tokyo
JP
|
Family ID: |
60303354 |
Appl. No.: |
15/161999 |
Filed: |
May 23, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G11B 5/112 20130101;
G11B 5/3146 20130101; G11B 5/3163 20130101; G11B 5/1278 20130101;
H01L 21/027 20130101; H01L 45/1675 20130101; H01L 45/1683 20130101;
H01L 45/1691 20130101; G11B 5/315 20130101 |
International
Class: |
G11B 5/127 20060101
G11B005/127; H01L 45/00 20060101 H01L045/00; H01L 21/027 20060101
H01L021/027; G11B 5/39 20060101 G11B005/39; G11B 5/11 20060101
G11B005/11 |
Claims
1. A manufacturing method for a magnetic head, the magnetic head
comprising: a medium facing surface configured to face a recording
medium; a main pole for producing a write magnetic field for use to
write data on the recording medium by means of a perpendicular
magnetic recording system; a write shield formed of a magnetic
material; and a gap section formed of a nonmagnetic material and
separating the write shield from the main pole, wherein the main
pole has: an end face located in the medium facing surface; a top
surface located at a front-side end of the main pole in a direction
of travel of the recording medium; and a bottom end opposite to the
top surface, the write shield includes a leading shield located on
a rear side in the direction of travel of the recording medium
relative to the main pole, and a first side shield and a second
side shield located on opposite sides of the main pole in a track
width direction, the leading shield has a leading shield end face
located in the medium facing surface and a top surface opposed to
the bottom end of the main pole, the leading shield end face being
located on the rear side in the direction of travel of the
recording medium relative to the end face of the main pole, the top
surface of the leading shield includes a first portion and a second
portion, and a step between the first portion and the second
portion, the first portion has an end located in the medium facing
surface, the second portion is located farther from the medium
facing surface than is the first portion, and recessed from the
first portion, the gap section includes a first gap layer and a
second gap layer, the first gap layer is interposed between the
second portion and the second gap layer, and the second gap layer
has a front end located in the medium facing surface, separates the
main pole from the leading shield, the first and second side
shields and the first gap layer, and the second gap layer is
interposed between the first portion of the top surface of the
leading shield and the bottom end of the main pole, whereas the
first gap layer is not interposed between the first portion of the
top surface of the leading shield and the bottom end of the main
pole, the manufacturing method comprising the steps of: forming the
leading shield; forming the first gap layer on the second portion
of the top surface of the leading shield after the leading shield
is formed; forming a mold after the first gap layer is formed, the
mold including a first receiving section and a second receiving
section for receiving the first side shield and the second side
shield, the mold further including a midsection which is located
between the first and second receiving sections and forms a gap
between the first portion and the first gap layer; forming a
magnetic layer, the magnetic layer including an initial first side
shield received in the first receiving section, an initial second
side shield received in the second receiving section, and a
coupling section located in the gap and coupling the initial first
side shield and the initial second side shield to each other;
removing the mold after the magnetic layer is formed; removing the
coupling section after the mold is removed, by etching the magnetic
layer so that the initial first side shield becomes the first side
shield and the initial second side shield becomes the second side
shield; forming the second gap layer after the coupling section is
removed; and forming the main pole after the second gap layer is
formed.
2. The manufacturing method for the magnetic head according to
claim 1, wherein the step of forming the mold includes the steps
of: forming a first resist layer in regions where the first initial
side shield and the second initial side shield are to be located
later; forming a separating film to cover the first resist layer;
forming a second resist layer on the separating film, the second
resist layer being intended to become the mold later; and removing
the first resist layer and at least part of the separating film so
that the second resist layer remains and becomes the mold.
3. The manufacturing method for the magnetic head according to
claim 1, wherein the step of forming the leading shield includes
the steps of: forming an initial leading shield having a top
surface, the top surface including a first region to become the
first portion and a second region to be etched later to form the
second portion; and etching the second region of the top surface of
the initial leading shield so that the first region becomes the
first portion and the second portion is formed by the etching of
the second region to thereby make the initial leading shield into
the leading shield.
4. The manufacturing method for the magnetic head according to
claim 1, wherein the top surface of the leading shield has a first
end located in the medium facing surface and a second end opposite
to the first end, and the top surface of the leading shield is
inclined with respect to the medium facing surface and a direction
perpendicular to the medium facing surface such that the second end
is located on the rear side in the direction of travel of the
recording medium relative to the first end.
5. The manufacturing method for the magnetic head according to
claim 1, wherein the write shield further includes a trailing
shield located on a front side in the direction of travel of the
recording medium relative to the main pole, and the gap section
further includes a third gap layer for separating the trailing
shield from the top surface of the main pole, the manufacturing
method further comprising the steps of: forming the third gap layer
after the main pole is formed; and forming the trailing shield
after the third gap layer is formed.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to a manufacturing method for
a magnetic head including a main pole and a write shield.
2. Description of Related Art
[0002] The recording systems of magnetic recording devices such as
magnetic disk drives include a longitudinal magnetic recording
system in which the magnetization of signals is directed along the
plane of a recording medium (the longitudinal direction), and a
perpendicular magnetic recording system in which the magnetization
of signals is directed perpendicular to the plane of a recording
medium. It is known that the perpendicular magnetic recording
system is harder to be affected by thermal fluctuation of the
recording medium and capable of providing higher linear recording
density, compared with the longitudinal magnetic recording
system.
[0003] Magnetic heads for perpendicular magnetic recording
typically have, like those for longitudinal magnetic recording, a
structure in which a read head unit having a magnetoresistance
element (hereinafter, also referred to as MR element) for reading
and a write head unit having an induction-type electromagnetic
transducer for writing are stacked on the top surface of a
substrate.
[0004] A magnetic head for use in a magnetic disk drive is
typically incorporated in a slider. The slider has a medium facing
surface configured to face a recording medium. The medium facing
surface has an air inflow end (a leading end) and an air outflow
end (a trailing end). The slider is configured to slightly fly over
the surface of the recording medium by means of an airflow that
comes from the leading end into the space between the medium facing
surface and the recording medium. The recording medium includes a
magnetic recording layer. Tracks are concentrically formed in the
magnetic recording layer. The tracks are the area of the magnetic
recording layer on which data is to be written.
[0005] The write head unit includes a main pole. The main pole has
an end face located in the medium facing surface, and produces,
from the end face, a write magnetic field in a direction
perpendicular to the plane of the recording medium.
[0006] Here, the side of the positions closer to the leading end
relative to a reference position will be referred to as the leading
side, and the side of the positions closer to the trailing end
relative to the reference position will be referred to as the
trailing side. The leading side is the rear side in the direction
of travel of the recording medium relative to the slider. The
trailing side is the front side in the direction of travel of the
recording medium relative to the slider.
[0007] The magnetic head is typically disposed near the trailing
end of the medium facing surface of the slider. In a magnetic disk
drive, positioning of the magnetic head is performed by a rotary
actuator, for example. In this case, the magnetic head moves over
the recording medium along a circular orbit about the center of
rotation of the rotary actuator. In such a magnetic disk drive, a
tilt of the magnetic head with respect to the tangent of the
circular track, which is called a skew, occurs depending on the
position of the magnetic head across the tracks.
[0008] Particularly, in a magnetic disk drive of the perpendicular
magnetic recording system which is higher in capability of writing
on a recording medium than the longitudinal magnetic recording
system, there may occur the phenomenon that signals already written
on one or more tracks in the neighborhood of a track targeted for
writing are erased or attenuated during writing of a signal on the
track targeted for writing. In the present application, this
phenomenon will be called unwanted erasure. Unwanted erasure
includes adjacent track erasure (ATE) and wide-area track erasure
(WATE). Unwanted erasure is noticeably encountered upon occurrence
of a skew. For enhancement of recording density, it is necessary to
prevent unwanted erasure.
[0009] A known technique for preventing unwanted erasure and
enhancing the recording density is to provide a wrap-around shield
and a gap section, the wrap-around shield being a write shield
having an end face that is located in the medium facing surface and
surrounds the end face of the main pole, the gap section separating
the wrap-around shield from the main pole. This technique is
disclosed in, for example, U.S. Pat. Nos. 8,472,137 B2, 8,427,781
B1 and 8,289,649 B2.
[0010] The wrap-around shield includes a leading shield, first and
second side shields, and a trailing shield. The leading shield has
an end face located in the medium facing surface at a position on
the leading side of the end face of the main pole. The first and
second side shields have two end faces located in the medium facing
surface at positions on opposite sides of the end face of the main
pole in the track width direction. The trailing shield has an end
face located in the medium facing surface at a position on the
trailing side of the end face of the main pole.
[0011] The gap section includes a leading gap section for
separating the leading shield from the main pole, first and second
side gap sections for separating the first and second side shields
from the main pole, and a trailing gap section for separating the
trailing shield from the main pole.
[0012] The wrap-around shield has the function of capturing a
magnetic flux that is produced from the end face of the main pole
and spreads in directions other than the direction perpendicular to
the plane of the recording medium, and thereby preventing the
magnetic flux from reaching the recording medium. A magnetic head
provided with the wrap-around shield is able to prevent unwanted
erasure and provide further enhanced recording density.
[0013] The position of an end of a record bit to be recorded on the
recording medium is determined by the position of the trailing-side
edge (hereinafter referred to as the top edge) of the end face of
the main pole in the medium facing surface. Accordingly, what are
important for enhancing the write characteristics of the write head
unit include: high write magnetic field strength at the top edge or
in the vicinity thereof; and a large gradient of change in the
write magnetic field strength at the top edge or in the vicinity
thereof in the distribution of the write magnetic field strength in
the direction in which the tracks extend. High write magnetic field
strength at the top edge or in the vicinity thereof contributes to
the enhancement of overwrite property. A large gradient of change
in the write magnetic field strength at the top edge or in the
vicinity thereof contributes to the reduction of bit error
rate.
[0014] A magnetic head provided with the wrap-around shield suffers
from the problem that when a large amount of magnetic flux leaks
from the main pole to the wrap-around shield, particularly to the
leading shield and the first and second side shields, there occurs
reductions in the write magnetic field strength and the
aforementioned gradient of change at the top edge of the end face
of the main pole or in the vicinity of the top edge, and the write
characteristics are thereby degraded.
[0015] Now, we will discuss a configuration in which the thickness
of the leading gap section is constant regardless of distance from
the medium facing surface. First, assume that the thickness of the
leading gap section is small. In this case, the end face of the
main pole and the end face of the leading shield are at a small
distance from each other in the medium facing surface. Thus, the
write shield can fully perform the function of capturing a magnetic
flux that is produced from the end face of the main pole and
spreads in directions other than the direction perpendicular to the
plane of the recording medium. However, because of the small
distance between the main pole and the leading shield, flux leakage
from the main pole to the leading shield increases to degrade the
write characteristics.
[0016] Next, assume that the thickness of the leading gap section
is large. In this case, it is possible to reduce flux leakage from
the main pole to the leading shield. However, because of a large
distance between the end face of the main pole and the end face of
the leading shield in the medium facing surface, the write shield
cannot perform its function satisfactorily.
[0017] In the magnetic head disclosed in U.S. Pat. No. 8,427,781
B1, the main pole has a bottom end located at the leading-side
edge. The bottom end includes a first inclined portion, a first
flat portion, a second inclined portion, and a second flat portion
arranged in this order, the first inclined portion being closest to
the medium facing surface. In this magnetic head, the leading
shield has a first inclined surface opposed to the first inclined
portion, and a second inclined surface located farther from the
medium facing surface than the first inclined surface. The distance
between the second inclined surface and the second inclined portion
is greater than the distance between the first inclined surface and
the first inclined portion.
[0018] In the magnetic head disclosed in U.S. Pat. No. 8,427,781
B1, a step exists between the first inclined portion and the second
inclined portion at the bottom end of the main pole. In this
magnetic head, due to the existence of the step, the main pole is
small in volume and magnetic flux is likely to leak out of the main
pole. These factors result in degradation of the write
characteristics of the magnetic head.
[0019] U.S. Pat. No. 8,289,649 B2 discloses a manufacturing method
for a magnetic head as follows. According to the manufacturing
method, a mold is formed on the top surface of the leading shield
by photolithography. The mold includes first and second receiving
sections for receiving the first and second side shields, and a
midsection located between the first receiving section and the
second receiving section. Then, the first and second side shields
are formed by plating so as to be received in the first and second
receiving sections. The mold is then removed. Then, a gap layer is
formed. The gap layer includes a leading gap section and first and
second side gap sections. Then, the main pole is formed.
[0020] This manufacturing method is likely to generate a gap
between the midsection of the mold and the top surface of the
leading shield. If the gap is generated, a magnetic material used
for forming the first and second side shields gets into the gap in
the process of forming the first and second side shields. This
results in the formation of unwanted coupling section coupling the
first and second side shields to each other. In such a case,
disadvantageously, the main pole becomes smaller in volume and the
write characteristics of the magnetic head are thus degraded.
OBJECT AND SUMMARY OF THE INVENTION
[0021] It is an object of the present invention to provide a
manufacturing method for a magnetic head that can prevent the
occurrence of unwanted erasure while suppressing degradation of
write characteristics.
[0022] A magnetic head manufactured by a manufacturing method of
the present invention includes: a medium facing surface configured
to face a recording medium; a main pole for producing a write
magnetic field for use to write data on the recording medium by
means of a perpendicular magnetic recording system; a write shield
formed of a magnetic material; and a gap section formed of a
nonmagnetic material and separating the write shield from the main
pole.
[0023] The main pole has: an end face located in the medium facing
surface; a top surface located at a front-side end of the main pole
in the direction of travel of the recording medium; and a bottom
end opposite to the top surface. The write shield includes a
leading shield located on the rear side in the direction of travel
of the recording medium relative to the main pole, and a first side
shield and a second side shield located on opposite sides of the
main pole in the track width direction.
[0024] The leading shield has a leading shield end face located in
the medium facing surface, and a top surface opposed to the bottom
end of the main pole. The leading shield end face is located on the
rear side in the direction of travel of the recording medium
relative to the end face of the main pole. The top surface of the
leading shield includes a first portion and a second portion. The
first portion has an end located in the medium facing surface. The
second portion is located farther from the medium facing surface
than is the first portion, and recessed from the first portion. The
gap section includes a first gap layer and a second gap layer. The
first gap layer is interposed between the second portion and the
second gap layer. The second gap layer has a front end located in
the medium facing surface. The second gap layer separates the main
pole from the leading shield, the first and second side shields and
the first gap layer.
[0025] The manufacturing method for the magnetic head of the
present invention includes the steps of: forming the leading
shield; forming the first gap layer on the second portion of the
top surface of the leading shield after the leading shield is
formed; forming a mold after the first gap layer is formed, the
mold including a first receiving section and a second receiving
section for receiving the first side shield and the second side
shield, the mold further including a midsection which is located
between the first and second receiving sections and forms a gap
between the first portion and the first gap layer; forming a
magnetic layer, the magnetic layer including an initial first side
shield received in the first receiving section, an initial second
side shield received in the second receiving section, and a
coupling section located in the gap and coupling the initial first
side shield and the initial second side shield to each other;
removing the mold after the magnetic layer is formed; removing the
coupling section after the mold is removed, by etching the magnetic
layer so that the initial first side shield becomes the first side
shield and the initial second side shield becomes the second side
shield; forming the second gap layer after the coupling section is
removed; and forming the main pole after the second gap layer is
formed.
[0026] In the manufacturing method for the magnetic head of the
present invention, the step of forming the mold may include the
steps of: forming a first resist layer in regions where the first
initial side shield and the second initial side shield are to be
located later; forming a separating film to cover the first resist
layer; forming a second resist layer on the separating film, the
second resist layer being intended to become the mold later; and
removing the first resist layer and at least part of the separating
film so that the second resist layer remains and becomes the
mold.
[0027] In the manufacturing method for the magnetic head of the
present invention, the step of forming the leading shield includes
the steps of: forming an initial leading shield having a top
surface, the top surface including a first region to become the
first portion and a second region to be etched later to form the
second portion; and etching the second region of the top surface of
the initial leading shield so that the first region becomes the
first portion and the second portion is formed by the etching of
the second region to thereby make the initial leading shield into
the leading shield.
[0028] In the manufacturing method for the magnetic head of the
present invention, the top surface of the leading shield may have a
first end located in the medium facing surface and a second end
opposite to the first end. In this case, the top surface of the
leading shield may be inclined with respect to the medium facing
surface and a direction perpendicular to the medium facing surface
such that the second end is located on the rear side in the
direction of travel of the recording medium relative to the first
end.
[0029] In the magnetic head manufactured by the manufacturing
method of the present invention, the write shield may further
include a trailing shield located on the front side in the
direction of travel of the recording medium relative to the main
pole. The gap section may further include a third gap layer for
separating the trailing shield from the top surface of the main
pole. In such a case, the manufacturing method for the magnetic
head of the present invention further includes the steps of:
forming the third gap layer after the main pole is formed; and
forming the trailing shield after the third gap layer is
formed.
[0030] The manufacturing method for the magnetic head of the
present invention allows for a reduction in leakage of magnetic
flux from the main pole to the leading shield by increasing the
distance between the bottom end of the main pole and the top
surface of the leading shield at a location apart from the medium
facing surface, while allowing the end face of the main pole and
the leading shield end face to be at a desired distance from each
other in the medium facing surface. According to the manufacturing
method, the coupling section is removed by etching the magnetic
layer after the mold is removed. This makes it possible to prevent
a volume reduction of the main pole and degradation of the write
characteristics of the magnetic head attributable to the coupling
section. Thus, the present invention allows for manufacture of a
magnetic head that is capable of preventing the occurrence of
unwanted erasure and is less prone to degradation of write
characteristics.
[0031] Other objects, features and advantages of the present
invention will become fully apparent from the following
description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a cross-sectional view showing the main part of a
magnetic head according to an embodiment of the invention.
[0033] FIG. 2 is a cross-sectional view showing the configuration
of the magnetic head according to the embodiment of the
invention.
[0034] FIG. 3 is a front view showing the medium facing surface of
the magnetic head according to the embodiment of the invention.
[0035] FIG. 4 is a perspective view showing a slider including the
magnetic head according to the embodiment of the invention.
[0036] FIG. 5 is a perspective view showing a head arm assembly of
the embodiment of the invention.
[0037] FIG. 6 is an explanatory diagram to illustrate the main part
of a magnetic recording device of the embodiment of the
invention.
[0038] FIG. 7 is a plan view of the magnetic recording device of
the embodiment of the invention.
[0039] FIG. 8A and FIG. 8B are cross-sectional views showing a step
of a manufacturing method for the magnetic head according to the
embodiment of the invention.
[0040] FIG. 9A and FIG. 9B are cross-sectional views showing a step
that follows the step shown in FIG. 8A and FIG. 8B.
[0041] FIG. 10A and FIG. 10B are cross-sectional views showing a
step that follows the step shown in FIG. 9A and FIG. 9B.
[0042] FIG. 11A and FIG. 11B are cross-sectional views showing a
step that follows the step shown in FIG. 10A and FIG. 10B.
[0043] FIG. 12A and FIG. 12B are cross-sectional views showing a
step that follows the step shown in FIG. 11A and FIG. 11B.
[0044] FIG. 13A and FIG. 13B are cross-sectional views showing a
step that follows the step shown in FIG. 12A and FIG. 12B.
[0045] FIG. 14A and FIG. 14B are cross-sectional views showing a
step that follows the step shown in FIG. 13A and FIG. 13B.
[0046] FIG. 15A and FIG. 15B are cross-sectional views showing a
step that follows the step shown in FIG. 14A and FIG. 14B.
[0047] FIG. 16A and FIG. 16B are cross-sectional views showing a
step that follows the step shown in FIG. 15A and FIG. 15B.
[0048] FIG. 17A and FIG. 17B are cross-sectional views showing a
step that follows the step shown in FIG. 16A and FIG. 16B.
[0049] FIG. 18A and FIG. 18B are cross-sectional views showing a
step that follows the step shown in FIG. 17A and FIG. 17B.
[0050] FIG. 19A and FIG. 19B are cross-sectional views showing a
step that follows the step shown in FIG. 18A and FIG. 18B.
[0051] FIG. 20A and FIG. 20B are cross-sectional views showing a
step that follows the step shown in FIG. 19A and FIG. 19B.
[0052] FIG. 21A and FIG. 21B are cross-sectional views showing a
step that follows the step shown in FIG. 20A and FIG. 20B.
[0053] FIG. 22A and FIG. 22B are cross-sectional views showing a
step that follows the step shown in FIG. 21A and FIG. 21B.
[0054] FIG. 23A and FIG. 23B are cross-sectional views showing a
step that follows the step shown in FIG. 22A and FIG. 22B.
[0055] FIG. 24A and FIG. 24B are cross-sectional views showing a
step that follows the step shown in FIG. 23A and FIG. 23B.
[0056] FIG. 25 is a cross-sectional view showing an example of a
magnetic layer having undergone the etching of a portion of each of
an initial first side shield and an initial second side shield.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0057] An embodiment of the present invention will now be described
in detail with reference to the drawings. First, reference is made
to FIG. 4 to describe a slider 210 including a magnetic head
according to the embodiment of the invention. The magnetic head
according to the embodiment is for use in perpendicular magnetic
recording. In a magnetic recording device, the slider 210 is
positioned to face a circular-plate-shaped recording medium (a
magnetic disk) configured to be driven to rotate. In FIG. 4, the X
direction is a direction across the tracks of the recording medium,
i.e., the track width direction. The Y direction is a direction
perpendicular to the surface of the recording medium. The Z
direction is the direction of travel of the recording medium as
viewed from the slider 210. The X, Y, and Z directions are
orthogonal to one another. The slider 210 has a base body 211. The
base body 211 is generally hexahedron-shaped. One of the six
surfaces of the base body 211 is configured to face the surface of
the recording medium. At this one of the six surfaces, there is
formed a medium facing surface 80 to face the surface of the
recording medium. When the recording medium rotates and travels in
the Z direction, an airflow passing between the recording medium
and the slider 210 causes a lift below the slider 210 in the Y
direction in FIG. 4. The lift causes the slider 210 to fly over the
surface of the recording medium. The magnetic head 100 according to
the embodiment is formed near the air-outflow-side end (the end in
the Z direction) of the slider 210. A plurality of terminals 212
are also provided at the air-outflow-side end of the slider
210.
[0058] A head assembly of the embodiment will now be described with
reference to FIG. 5. The head assembly of the embodiment includes
the slider 210 shown in FIG. 4 and a supporter for flexibly
supporting the slider 210. Forms of the head assembly include a
head gimbal assembly and a head arm assembly described below.
[0059] The head gimbal assembly 220 will be described first. The
head gimbal assembly 220 includes the slider 210, and a suspension
221 serving as the supporter for flexibly supporting the slider
210. The suspension 221 includes: a plate-spring-shaped load beam
222 formed of, e.g., stainless steel; a flexure 223 to which the
slider 210 is joined, the flexure 223 being provided at one end of
the load beam 222 and giving an appropriate degree of freedom to
the slider 210; and a base plate 224 provided at the other end of
the load beam 222. The base plate 224 is configured to be attached
to an arm 230 of an actuator for moving the slider 210 along the X
direction across the tracks of the recording medium 262. The
actuator has the arm 230 and a voice coil motor for driving the arm
230. A gimbal section for maintaining the orientation of the slider
210 is provided in the portion of the flexure 223 on which the
slider 210 is mounted.
[0060] The head gimbal assembly 220 is attached to the arm 230 of
the actuator. An assembly including the arm 230 and the head gimbal
assembly 220 attached to the arm 230 is called a head arm assembly.
An assembly including a carriage having a plurality of arms with a
plurality of head gimbal assemblies 220 respectively attached to
the arms is called a head stack assembly.
[0061] FIG. 5 shows the head arm assembly of the embodiment. In the
head arm assembly, the head gimbal assembly 220 is attached to one
end of the arm 230. A coil 231 constituting part of the voice coil
motor is fixed to the other end of the arm 230. A bearing 233 is
provided in the middle of the arm 230. The bearing 233 is attached
to a shaft 234 for rotatably supporting the arm 230.
[0062] Reference is now made to FIG. 6 and FIG. 7 to describe an
example of the head stack assembly and an example of a magnetic
recording device of the embodiment. FIG. 6 is an explanatory
diagram illustrating the main part of the magnetic recording
device. FIG. 7 is a plan view of the magnetic recording device. The
head stack assembly 250 includes a carriage 251 having a plurality
of arms 252. A plurality of head gimbal assemblies 220 are attached
to the arms 252 such that the assemblies 220 are aligned in the
vertical direction with spacing between every adjacent ones. A coil
253 constituting part of the voice coil motor is mounted on a side
of the carriage 251 opposite from the arms 252. The head stack
assembly 250 is installed in the magnetic recording device. The
magnetic recording device includes a plurality of recording media
262 mounted on a spindle motor 261. Two sliders 210 are allocated
to each recording medium 262 such that the two sliders 210 are
opposed to each other with the recording medium 262 interposed
therebetween. The voice coil motor includes permanent magnets 263
arranged to be opposed to each other with the coil 253 of the head
stack assembly 250 interposed therebetween. The actuator and the
head stack assembly 250 except the sliders 210 support the sliders
210 and position them with respect to the recording media 262.
[0063] In the magnetic recording device, the actuator moves the
slider 210 across the tracks of the recording medium 262 and
positions the slider 210 with respect to the recording medium 262.
The magnetic head 100 included in the slider 210 is configured to
write data on the recording medium 262 by using a write head unit
and to read data stored on the recording medium 262 by using a read
head unit.
[0064] Reference is now made to FIG. 2 and FIG. 3 to describe the
configuration of the magnetic head according to the embodiment.
FIG. 2 is a cross-sectional view showing the configuration of the
magnetic head. FIG. 3 is a front view showing the medium facing
surface of the magnetic head. FIG. 2 shows a cross section
perpendicular to the medium facing surface and to the top surface
of the substrate. The X, Y, and Z directions shown in FIG. 4 are
also shown in FIG. 2 and FIG. 3. In FIG. 2, the X direction is a
direction orthogonal to the Y and Z directions. In FIG. 3, the Y
direction is a direction orthogonal to the X and Z directions.
[0065] As shown in FIG. 2, the magnetic head according to the
embodiment has the medium facing surface 80 configured to face the
recording medium. As shown in FIG. 2 and FIG. 3, the magnetic head
includes: a substrate 10 formed of a ceramic material such as
aluminum oxide-titanium carbide (Al.sub.2O.sub.3--TiC); an
underlying layer 11 formed of an insulating material such as
alumina (Al.sub.2O.sub.3) and lying on the substrate 10; a bottom
read shield layer 20 formed of a magnetic material and lying on the
underlying layer 11; a magnetoresistance element (hereinafter
referred to as MR element) 21 lying on the bottom read shield layer
20; and a top read shield layer 22 formed of a magnetic material
and lying on the MR element 21.
[0066] An end of the MR element 21 is located in the medium facing
surface 80. The MR element 21 may be a giant magnetoresistance
(GMR) element or a tunneling magnetoresistance (TMR) element, for
example. The GMR element may be of either the current-in-plane
(CIP) type in which a sense current for use in magnetic signal
detection is fed in a direction generally parallel to the plane of
layers constituting the GMR element or the
current-perpendicular-to-plane (CPP) type in which the sense
current is fed in a direction generally perpendicular to the plane
of layers constituting the GMR element. Where the MR element 21 is
a TMR element or a CPP-type GMR element, the bottom read shield
layer 20 and the top read shield layer 22 may also serve as
electrodes for feeding the sense current to the MR element 21.
Where the MR element 21 is a CIP-type GMR element, insulating films
are respectively provided between the MR element 21 and the bottom
read shield layer 20 and between the MR element 21 and the top read
shield layer 22, and two leads are provided between these
insulating films in order to feed the sense current to the MR
element 21.
[0067] The magnetic head further includes: an insulating layer 23
formed of an insulating material and disposed around the bottom
read shield layer 20; an insulating layer 24 formed of an
insulating material, disposed between the bottom read shield layer
20 and the top read shield layer 22 and surrounding the MR element
21; and an insulating layer 25 formed of an insulating material and
disposed around the top read shield layer 22. The insulating layers
23 to 25 are formed of alumina, for example. The parts from the
bottom read shield layer 20 to the top read shield layer 22
constitute the read head unit.
[0068] The magnetic head further includes an insulating film 26
formed of an insulating material and lying on the top read shield
layer 22 and the insulating layer 25, and the write head unit lying
on the insulating film 26. The insulating film 26 is formed of
alumina, for example.
[0069] The write head unit includes a coil 66 and a main pole 52.
The coil 66 produces a magnetic field corresponding to data to be
written on the recording medium. The main pole 52 has an end face
52a located in the medium facing surface 80. The main pole 52
passes a magnetic flux corresponding to the magnetic field produced
by the coil 66, and produces a write magnetic field for use to
write data on the recording medium by means of the perpendicular
magnetic recording system. The coil 66 is formed of a conductive
material such as copper.
[0070] As shown in FIG. 3, the write head unit further includes a
write shield 110 formed of a magnetic material, and a gap section
120 formed of a nonmagnetic material. The write shield 110 includes
a trailing shield 62, a leading shield 40, a first side shield 50A
and a second side shield 50B. The trailing shield 62 is located on
the trailing side, i.e., the front side in the direction of travel
of the recording medium (the Z direction), relative to the main
pole 52. The leading shield 40 is located on the leading side,
i.e., the rear side in the direction of travel of the recording
medium (the Z direction), relative to the main pole 52. The first
and second side shields 50A and 50B are located on opposite sides
of the main pole 52 in the track width direction (the X direction).
The gap section 120 separates the write shield 110 from the main
pole 52.
[0071] The write head unit further includes a middle shield layer
30 formed of a magnetic material and lying on the insulating film
26, and an insulating layer 31 formed of an insulating material and
disposed around the middle shield layer 30. The insulating layer 31
is formed of alumina, for example. The top surfaces of the middle
shield layer 30 and the insulating layer 31 are even with each
other.
[0072] The write head unit further includes an insulating film 32
formed of an insulating material and lying on the middle shield
layer 30 and the insulating layer 31, and a coil 33 formed of a
conductive material and lying on the insulating film 32. The coil
33 is planar spiral-shaped. The write head unit further includes an
insulating layer 34 formed of an insulating material and disposed
around the coil 33 and in the space between adjacent turns of the
coil 33. The insulating film 32 and the insulating layer 34 are
formed of alumina, for example. The top surfaces of the coil 33 and
the insulating layer 34 are even with each other.
[0073] The write head unit further includes an insulating film 35
formed of an insulating material and lying on the coil 33 and the
insulating layer 34. The insulating film 35 is formed of alumina,
for example.
[0074] The leading shield 40 includes a first layer 41 lying on the
insulating film 35, a second layer 42 lying on the first layer 41,
and a third layer 43 lying on the first layer 41 and the second
layer 42. As shown in FIG. 3, the second layer 42 is smaller than
the first layer 41 in width in the track width direction (the X
direction).
[0075] The write head unit further includes an insulating layer 44
formed of an insulating material and surrounding the first layer 41
of the leading shield 40. The insulating layer 44 is formed of
alumina, for example.
[0076] The first and second side shields 50A and 50B are located on
the leading shield 40 and adjacent to each other in the track width
direction (the X direction) with spacing therebetween. The first
side shield 50A has a first sidewall opposed to a first side
surface of the main pole 52 to be described later. The second side
shield 50B has a second sidewall opposed to a second side surface
of the main pole 52 to be described later.
[0077] As shown in FIG. 2, the gap section 120 includes a first gap
layer 45 and a second gap layer 46 each formed of a nonmagnetic
material. The first gap layer 45 lies on a part of the top surface
of the leading shield 40 and a part of the top surface of the
insulating layer 44. As shown in FIG. 2 and FIG. 3, the second gap
layer 46 is provided to extend along the first and second sidewalls
of the first and second side shields 50A and 50B, another part of
the top surface of the leading shield 40, and the top surface of
the first gap layer 45. The first gap layer 45 is formed of
SiO.sub.2, for example. The second gap layer 46 is formed of
alumina, for example. The shape and locations of the first and
second gap layers 45 and 46 will be described in more detail
later.
[0078] The main pole 52 lies above the leading shield 40 and the
insulating layer 44. The first and second gap layers 45 and 46 are
interposed between the main pole 52 and each of the leading shield
40, the insulating layer 44 and the first and second side shields
50A and 50B.
[0079] The main pole 52 has a top surface 52T (see FIG. 2), a
bottom end 52L (see FIG. 2), and a first side surface S1 and a
second side surface S2 (see FIG. 3) in addition to the end face 52a
mentioned previously. The top surface 52T is located at the
trailing-side end of the main pole 52, i.e., the front-side end of
the main pole 52 in the direction of travel of the recording medium
(the Z direction). The bottom end 52L is opposite to the top
surface 52T. The first and second side surfaces S1 and S2 are
located at opposite ends of the main pole 52 in the track width
direction (the X direction). The shape of the main pole 52 will be
described in detail later.
[0080] The write head unit further includes a nonmagnetic layer 53
formed of a nonmagnetic material and disposed around the first and
second side shields 50A and 50B and the main pole 52. The
nonmagnetic layer 53 is formed of alumina, for example.
[0081] The write head unit further includes a nonmagnetic layer 54
formed of a nonmagnetic material and lying on a first portion of
the top surface 52T of the main pole 52, the first portion being
located away from the medium facing surface 80. The nonmagnetic
layer 54 has a front end closest to the medium facing surface 80.
The nonmagnetic layer 54 includes a wedge-shaped portion whose
thickness decreases toward the medium facing surface 80. The
wedge-shaped portion includes the aforementioned front end.
[0082] The nonmagnetic layer 54 is formed of an inorganic
insulating material or a metal material, for example. Examples of
inorganic insulating materials that can be used to form the
nonmagnetic layer 54 include alumina and SiO.sub.2. Examples of
metal materials that can be used to form the nonmagnetic layer 54
include Ru and Ti.
[0083] The gap section 120 further includes a third gap layer 60
and a fourth gap layer 61 each formed of a nonmagnetic material.
The third gap layer 60 lies on the nonmagnetic layer 54 and part of
the main pole 52. The fourth gap layer 61 lies on the third gap
layer 60 at a location away from the medium facing surface 80. The
third and fourth gap layers 60 and 61 are formed of alumina, for
example.
[0084] The write head unit further includes a return path section
130 formed of a magnetic material. The return path section 130
includes a first yoke layer 63 and a second yoke layer 68. The
first yoke layer 63 lies on a second portion of the top surface 52T
of the main pole 52, the second portion being located away from the
medium facing surface 80. The second portion of the top surface 52T
of the main pole 52 is located farther from the medium facing
surface 80 than is the first portion of the top surface 52T of the
main pole 52.
[0085] The trailing shield 62 lies on the first side shield 50A,
the second side shield 50B, the third gap layer 60 and the fourth
gap layer 61. The write head unit further includes an insulating
layer 64 formed of an insulating material and disposed around the
trailing shield 62 and the first yoke layer 63. The insulating
layer 64 is formed of alumina, for example. The top surfaces of the
trailing shield 62, the first yoke layer 63 and the insulating
layer 64 are even with each other.
[0086] The write head unit further includes an insulating film 65
formed of an insulating material and lying on the insulating layer
64. The coil 66 lies on the insulating film 65. The write head unit
further includes an insulating film 67 formed of an insulating
material and disposed to cover the insulating film 65 and the coil
66. The insulating films 65 and 67 are formed of alumina, for
example. The coil 66 is planar spiral-shaped.
[0087] The second yoke layer 68 lies on the trailing shield 62, the
first yoke layer 63 and the insulating film 67, and connects the
trailing shield 62 and the first yoke layer 63.
[0088] The magnetic head further includes a protective layer 69
formed of an insulating material such as alumina and disposed to
cover the second yoke layer 68. The base body 211 shown in FIG. 4
is mainly constituted by the substrate 10 and the protective layer
69 shown in FIG. 2 and FIG. 3.
[0089] As has been described, the magnetic head according to the
embodiment includes the medium facing surface 80, the read head
unit, and the write head unit. The read head unit and the write
head unit are stacked on the substrate 10. The read head unit is
located on the leading side, i.e., the rear side in the direction
of travel of the recording medium (the Z direction), relative to
the write head unit.
[0090] The write head unit includes the coil 66, the main pole 52,
the write shield 110, the gap section 120, and the return path
section 130. The write shield 110 includes the trailing shield 62,
the leading shield 40, and the first and second side shields 50A
and 50B. The gap section 120 includes the first gap layer 45, the
second gap layer 46, the third gap layer 60 and the fourth gap
layer 61. The return path section 130 includes the first yoke layer
63 and the second yoke layer 68.
[0091] As shown in FIG. 2, the return path section 130 connects the
trailing shield 62 and part of the main pole 52 located away from
the medium facing surface 80 to each other so that a space is
defined by the main pole 52, the third and fourth gap layers 60 and
61, the write shield 110 and the return path section 130. The coil
66 includes a portion passing through the aforementioned space.
[0092] The write shield 110 captures a disturbance magnetic field
applied to the magnetic head from the outside thereof. This makes
it possible to prevent the disturbance magnetic field from being
intensively captured into the main pole 52 and thereby causing
erroneous writing on the recording medium. The write shield 110
also has the function of capturing a magnetic flux that is produced
from the end face 52a of the main pole 52 and spreads in directions
other than a direction perpendicular to the plane of the recording
medium, and thereby preventing the magnetic flux from reaching the
recording medium. Furthermore, the write shield 110 and the return
path section 130 have the function of allowing a magnetic flux that
has been produced from the end face 52a of the main pole 52 and has
magnetized a portion of the recording medium to flow back to the
main pole 52.
[0093] The write head unit further includes the middle shield layer
30 and the coil 33. When a write current is supplied to the coils
33 and 66, magnetic fields are produced at the respective center
portions of the coils 33 and 66 in mutually opposite directions.
The coil 66 produces a magnetic field corresponding to data to be
written on the recording medium. The coil 33 produces a magnetic
field that prevents the magnetic field produced by the coil 66 from
affecting the read head unit. The middle shield layer 30 has the
function of shielding the read head unit from magnetic fields
produced in the write head unit.
[0094] The main pole 52, the write shield 110 and the gap section
120 will now be described in detail with reference to FIG. 1 to
FIG. 3. FIG. 1 is a cross-sectional view showing the main part of
the magnetic head. As shown in FIG. 1, the top surface 52T of the
main pole 52 includes a first inclined portion 52T1 and a first
flat portion 52T2, the first inclined portion 52T1 being closer to
the medium facing surface 80 than the first flat portion 52T2. The
first inclined portion 52T1 has a first end located in the medium
facing surface 80 and a second end opposite thereto. The first flat
portion 52T2 is connected to the second end. The first inclined
portion 52T1 is inclined such that the second end is located on the
trailing side, i.e., the front side in the direction of travel of
the recording medium (the Z direction), relative to the first end.
The first flat portion 52T2 extends in a direction substantially
perpendicular to the medium facing surface 80.
[0095] As shown in FIG. 1, the bottom end 52L of the main pole 52
includes a second inclined portion 52L1 and a second flat portion
52L2, the second inclined portion 52L1 being closer to the medium
facing surface 80 than the second flat portion 52L2. The second
inclined portion 52L1 has a third end located in the medium facing
surface 80 and a fourth end opposite thereto. The second inclined
portion 52L1 may be an edge formed by two intersecting planes, or
may be a plane connecting two planes to each other. The second flat
portion 52L2 is a plane connected to the fourth end of the second
inclined portion 52L1. The second inclined portion 52L1 is inclined
such that the fourth end is located on the leading side, i.e., the
rear side in the direction of travel of the recording medium (the Z
direction), relative to the third end. The second flat portion 52L2
extends in a direction substantially perpendicular to the medium
facing surface 80.
[0096] As shown in FIG. 3, the end face 52a of the main pole 52 has
a top edge located at an end of the top surface 52T of the main
pole 52, a first side edge located at an end of the first side
surface S1 of the main pole 52, and a second side edge located at
an end of the second side surface S2 of the main pole 52. The
length of the top edge defines the track width. The position of an
end of a record bit to be recorded on the recording medium is
determined by the position of the top edge. The distance between
the first side edge and the second side edge in the track width
direction (the X direction) decreases with increasing distance from
the top edge. In the example shown in FIG. 3, the end face 52a of
the main pole 52 further has a bottom edge located at an end of the
bottom end 52L of the main pole 52.
[0097] Although not illustrated, the main pole 52 may include a
width-changing portion. In the width-changing portion, the width of
the top surface 52T in the track width direction (the X direction)
increases with increasing distance from the medium facing surface
80. The main pole 52 may further include a constant width portion
located between the medium facing surface 80 and the width-changing
portion. In the width-changing portion, the width of the top
surface 52T in the track width direction (the X direction) is
substantially constant regardless of distance from the medium
facing surface 80.
[0098] As shown in FIG. 1 and FIG. 3, the trailing shield 62 of the
write shield 110 has a trailing shield end face 62a located in the
medium facing surface 80, and a bottom surface 62b opposed to the
top surface 52T of the main pole 52. The trailing shield end face
62a is located on the trailing side, i.e., the front side in the
direction of travel of the recording medium (the Z direction),
relative to the end face 52a of the main pole 52. The leading
shield 40 of the write shield 110 has a leading shield end face 40a
located in the medium facing surface 80, and a top surface 40b
opposed to the bottom end 52L of the main pole 52. The leading
shield end face 40a is located on the leading side, i.e., the rear
side in the direction of travel of the recording medium, relative
to the end face 52a of the main pole 52. As shown in FIG. 3, the
first side shield 50A and the second side shield 50B of the write
shield 110 respectively have a first side shield end face 50Aa and
a second side shield end face 50Ba located on opposite sides of the
end face 52a of the main pole 52 in the track width direction (the
X direction) in the medium facing surface 80.
[0099] As shown in FIG. 1, the top surface 40b of the leading
shield 40 includes a first portion 40b1 and a second portion 40b2.
The first portion 40b1 has an end located in the medium facing
surface 80. This end of the first portion 40b1 will be referred to
as the first end and denoted by symbol E1. The second portion 40b2
is located farther from the medium facing surface 80 than is the
first portion 40b1, and recessed from the first portion 40b1. There
is formed a step 40b3 between the first portion 40b1 and the second
portion 40b2.
[0100] The second inclined portion 52L1 of the bottom end 52L of
the main pole 52 includes a third portion 52L11 opposed to the
first portion 40b1, and a fourth portion 52L12 opposed to the
second portion 40b2. As shown in FIG. 1, there is no step between
the third portion 52L11 and the fourth portion 52L12.
[0101] As shown in FIG. 1, the top surface 40b of the leading
shield 40 has the first end E1 mentioned above, and a second end E2
opposite to the first end E1. The top surface 40b of the leading
shield 40 is inclined with respect to the medium facing surface 80
and the direction perpendicular to the medium facing surface 80
such that the second end E2 is located on the rear side in the
direction of travel of the recording medium relative to the first
end E1.
[0102] The first layer 41 of the leading shield 40 has a front end
face located in the medium facing surface 80, a rear end face
opposite to the front end face, a top surface, and an inclined
surface 41a connecting the rear end face and the top surface. The
second layer 42 of the leading shield 40 has a front end face
located in the medium facing surface 80, and a top surface. The top
surface of the second layer 42 includes a first inclined portion
42a and a second inclined portion 42b. The first inclined portion
42a has an end located in the medium facing surface 80. The second
inclined portion 42b is located farther from the medium facing
surface 80 than is the first inclined portion 42a, and recessed
from the first inclined portion 42a. The inclined surface 41a of
the first layer 41 is contiguous with the second inclined portion
42b. Part of the third layer 43 of the leading shield 40 extends
along the first inclined portion 42a. The third layer 43 has a
front end face located in the medium facing surface 80, and a top
surface. The leading shield end face 40a is formed by the
respective front end faces of the first layer 41, the second layer
42 and the third layer 43. The first portion 40b1 of the top
surface 40b of the leading shield 40 is formed by the top surface
of the third layer 43. The second portion 40b2 of the top surface
40b of the leading shield 40 is formed by the inclined surface 41a
of the first layer 41 and the second inclined portion 42b of the
top surface of the second layer 42.
[0103] As shown in FIG. 1, the bottom surface 62b of the trailing
shield 62 includes a fifth portion 62b1 and a sixth portion 62b2.
The fifth portion 62b1 has an end located in the medium facing
surface 80. The sixth portion 62b2 is located farther from the
medium facing surface 80 than is the fifth portion 62b1. There is
formed a step 62b3 between the fifth portion 62b1 and the sixth
portion 62b2. The first inclined portion 52T1 of the top surface
52T of the main pole 52 includes a seventh portion opposed to the
fifth portion 62b1, and an eighth portion opposed to the sixth
portion 62b2. The bottom surface 62b has a first end located in the
medium facing surface 80 and a second end opposite to the first
end. The bottom surface 62b is inclined with respect to the medium
facing surface 80 and the direction perpendicular to the medium
facing surface 80 such that the second end is located on the front
side in the direction of travel of the recording medium relative to
the first end.
[0104] As shown in FIG. 1, the first gap layer 45 of the gap
section 120 has a front end 45a located closest to but at a
distance from the medium facing surface 80. The distance from the
medium facing surface 80 to the front end 45a is smaller than the
distance from the medium facing surface 80 to the fourth end of the
second inclined portion 52L1 of the bottom end 52L of the main pole
52. The first gap layer 45 is interposed between the second portion
40b2 of the top surface 40b of the leading shield 40 and the second
gap layer 46. The second gap layer 46 has a front end 46a located
in the medium facing surface 80. The second gap layer 46 separates
the main pole 52 from the leading shield 40, the first and second
side shields 50A and 50B and the first gap layer 45.
[0105] A portion of the first gap layer 45 that is interposed
between the second portion 40b2 and the second gap layer 46 will be
referred to as the interposition portion. In this embodiment, the
thickness of the interposition portion of the first gap layer 45 is
equal to the height of the step 40b3 between the first portion 40b1
and the second portion 40b2 of the top surface 40b of the leading
shield 40. Thus, there is no step between the first portion 40b1
and the top surface of the interposition portion of the first gap
layer 45. A portion of the second gap layer 46 that lies on the
first portion 40b1 and the interposition portion of the first gap
layer 45 has a flat top surface.
[0106] The second gap layer 46 is interposed between the first
portion 40b1 and the third portion 52L11, whereas the first gap
layer 45 is not interposed therebetween. The first and second gap
layers 45 and 46 are interposed between the second portion 40b2 and
the fourth portion 52L12. More specifically, the interposition
portion of the first gap layer 45 and the second gap layer 46 are
stacked in this order between the second portion 40b2 and the
fourth portion 52L12. As previously described, there is no step
between the third portion 52L11 and the fourth portion 52L12 which
are respectively opposed to the first portion 40b1 and the top
surface of the interposition portion of the first gap layer 45.
[0107] The third gap layer 60 has a front end located in the medium
facing surface 80. The third gap layer 60 separates the trailing
shield 62 from the top surface 52T of the main pole 52. The fourth
gap layer 61 has a front end located closest to but at a distance
from the medium facing surface 80. The distance from the medium
facing surface 80 to the front end of the fourth gap layer 61 is
smaller than the distance from the medium facing surface 80 to the
second end of the first inclined portion 52T1 of the top surface
52T of the main pole 52. The third gap layer 60 is interposed
between the fifth portion 62b1 of the bottom surface 62b of the
trailing shield 62 and the seventh portion of the first inclined
portion 52T1 of the top surface 52T of the main pole 52, whereas
the fourth gap layer 61 is not interposed therebetween. The third
and fourth gap layers 60 and 61 are interposed between the sixth
portion 62b2 of the bottom surface 62b of the trailing shield 62
and the eighth portion of the first inclined portion 52T1 of the
top surface 52T of the main pole 52.
[0108] A manufacturing method for the magnetic head according to
the embodiment will now be described. As shown in FIG. 2 and FIG.
3, the manufacturing method for the magnetic head according to the
embodiment first forms the underlying layer 11, the bottom read
shield layer 20 and the insulating layer 23 in this order on the
substrate 10. Next, the MR element 21 is formed on the bottom read
shield layer 20, and the insulating layer 24 is formed on the
bottom read shield layer 20 and the insulating layer 23. Then, the
top read shield layer 22, the insulating layer 25 and the
insulating film 26 are formed in this order on the MR element 21
and the insulating layer 24.
[0109] Next, the middle shield layer 30 is formed on the insulating
film 26 by frame plating, for example. The insulating layer 31 is
then formed to cover the middle shield layer 30. The insulating
layer 31 is then polished by, for example, chemical mechanical
polishing (hereinafter referred to as CMP), until the middle shield
layer 30 is exposed. Then, the insulating film 32 is formed over
the entire top surface of the stack. The coil 33 is then formed on
the insulating film 32 by frame plating, for example. The
insulating layer 34 is then formed to cover the coil 33. The
insulating layer 34 is then polished by, for example, CMP, until
the coil 33 is exposed. Then, the insulating film 35 is formed over
the entire top surface of the stack.
[0110] Reference is now made to FIG. 8A to FIG. 24B to describe a
series of steps following the formation of the insulating film 35.
FIG. 8A to FIG. 24B each show a stack of layers formed in the
process of manufacturing the magnetic head. FIG. nA (n is any
integer between 8 and 24 inclusive) shows a cross section of the
stack taken at the location at which the medium facing surface 80
is to be formed. Fig. nB shows a cross section perpendicular to the
medium facing surface 80 and to the top surface of the substrate
10. In FIG. nB, the reference symbol "ABS" denotes an imaginary
plane representative of the location at which the medium facing
surface 80 is to be formed.
[0111] FIG. 8A and FIG. 8B show the step following the formation of
the insulating film 35. In this step, first, an initial first layer
41P, which will later become the first layer 41 of the leading
shield 40, is formed on the insulating film 35 by frame plating,
for example. The insulating layer 44 is then formed to cover the
initial first layer 41P. The insulating layer 44 is then polished
by, for example, CMP, until the initial first layer 41P is exposed.
Next, an initial second layer 42P, which will later become the
second layer 42 of the leading shield 40, is formed on the initial
first layer 41P by sputtering, for example. Part of the initial
second layer 42P is then taper-etched by, for example, ion beam
etching. The initial second layer 42P having undergone this etching
has a bottom surface, a top surface 42Pa, and an inclined surface
42Pb connecting the top surface 42Pa and the bottom surface.
[0112] FIG. 9A and FIG. 9B show the next step. In this step, an
initial third layer 43P, which will later become the third layer 43
of the leading shield 40, is formed over the entire top surface of
the stack.
[0113] An initial leading shield 40P is formed through a series of
steps from the step shown in FIGS. 8A and 8B to the step shown in
FIGS. 9A and 9B. The initial leading shield 40P is constituted by
the initial first layer 41P, the initial second layer 42P and the
initial third layer 43P. The initial leading shield 40P has a top
surface 40Pa.
[0114] The top surface 40Pa includes a first region R1, a second
region R2 and a third region R3. The first region R1 and the second
region R2 are located above the inclined surface 42Pb of the
initial second layer 42P. The third region R3 is located above the
top surface 42Pa of the initial second layer 42P.
[0115] The first region R1 is a region to become the first portion
40b1 of the top surface 40b of the leading shield 40. The second
region R2 is a region to be etched later to form the second portion
40b2 of the top surface 40b of the leading shield 40. The third
region R3 is included in a part of the initial leading shield 40P
to be removed later. The first region R1 is located between the
second region R2 and the third region R3. The first region R1 and
the second region R2 are each inclined at the same angle as is the
first portion 40b1 of the top surface 40b to be formed later. The
third region R3 is parallel to the top surface of the substrate
10.
[0116] FIG. 10A and FIG. 10B show the next step. In this step, a
mask 81 is formed on the stack. The mask 81 is in contact with the
third region R3 of the top surface 40Pa of the initial leading
shield 40P. As shown in FIG. 10B, the mask 81 may also be in
contact with the first region R1. However, the mask 81 is not in
contact with the second region R2. The mask 81 includes an overhang
portion 81a located above the first region R1. The overhang portion
81a has an end face for defining the location of the step 40b3.
[0117] FIG. 11A and FIG. 11B show the next step. In this step, the
second region R2 (see FIG. 10B) of the top surface 40Pa of the
initial leading shield 40P is etched by, for example, ion beam
etching, using the mask 81. This makes the first region R1 (see
FIG. 10B) into the first portion 40b1 of the top surface 40b.
Further, the etching of the second region R2 results in the
formation of the second portion 40b2 of the top surface 40b. As a
result, the step 40b3 is formed between the first portion 40b1 and
the second portion 40b2. The aforementioned etching makes the
initial leading shield 40P into the leading shield 40. The initial
first layer 41P, the initial second layer 42P and the initial third
layer 43P become the first layer 41, the second layer 42 and the
third layer 43, respectively. The inclined surface 41a of the first
layer 41 is formed by etching of a portion of the top surface of
the initial first layer 41P. The second inclined portion 42b of the
top surface of the second layer 42 is formed by etching of a
portion of the inclined surface 42Pb of the initial second layer
42P. A portion of the inclined surface 42Pb of the initial second
layer 42P that remains after the etching makes the first inclined
portion 42a of the top surface of the second layer 42.
[0118] FIG. 12A and FIG. 12B show the next step. In this step, in
the presence of the mask 81, the first gap layer 45 is formed on
the second portion 40b2 by ion beam deposition, for example. The
first gap layer 45 is formed also on the insulating layer 44. The
material for forming the first gap layer 45 is deposited also onto
the surface of the mask 81. In FIG. 12A and FIG. 12B, the reference
symbol 45P represents a portion of the material for forming the
first gap layer 45 deposited on the surface of the mask 81. The
mask 81 is then removed (lifted off) as shown in FIG. 13A and FIG.
13B.
[0119] FIG. 14A and FIG. 14B show the next step. In this step,
first, a photoresist layer made of a positive photoresist is
patterned by photolithography to form a first resist layer 82 on
the regions of the top surface 40b of the leading shield 40 where
the first and second side shields 50A and 50B are to be formed
later. The first resist layer 82 includes a first portion 82A
shaped to correspond to the shape of the first side shield 50A to
be formed later, and a second portion 82B shaped to correspond to
the shape of the second side shield 50B to be formed later. Next, a
separating film 83 made of a nonmagnetic material is formed to
cover the first resist layer 82. The separating film 83 is provided
to prevent the first resist layer 82 made of a positive photoresist
from being mixed with a photoresist layer that is to be formed
later from a negative photoresist. Examples of materials suitable
for the separating film 83 include alumina and a synthetic resin.
Where alumina is selected as the material of the separating film
83, the separating film 83 is formed by atomic layer deposition,
for example.
[0120] FIG. 15A and FIG. 15B show the next step. In this step,
first, a photoresist layer made of a negative photoresist is
patterned by photolithography to form a second resist layer 84P on
the separating film 83. The second resist layer 84P will later
become the mold. The second resist layer 84P has an opening 84Pa
shaped to correspond to the shape of the first side shield 50A to
be formed later, an opening 84Pb shaped to correspond to the shape
of the second side shield 50B to be formed later, and an initial
midsection 84Pc located between the opening 84Pa and the opening
84Pb. Next, portions of the separating film 83 not covered by the
second resist layer 84P are removed by wet etching, for
example.
[0121] FIG. 16A and FIG. 16B show the next step. In this step, the
first resist layer 82 and at least part of the separating film 83
are removed so that the second resist layer 84P remains to become
the mold 84. More specifically, first, the entire top surface of
the stack is exposed to light. Having undergone the exposure, the
first resist layer 82 made of a positive photoresist becomes
soluble in a developing solution, while the second resist layer 84P
made of a negative photoresist remains insoluble in the developing
solution. Next, the first resist layer 82 is removed from the
openings 84Pa and 84Pb of the second resist layer 84P by using an
alkaline developing solution, for example. In this step, portions
of the separating film 83 extending along the wall faces of the
openings 84Pa and 84Pb of the second resist layer 84P are also
removed at the same time the first resist layer 82 is removed, or
by wet etching after the first resist layer 82 is removed. This
makes the second resist layer 84P into the mold 84. A series of
steps from the step shown in FIGS. 14A and 14B to the step shown in
FIGS. 16A and 16B corresponds to the step of forming the mold in
the present invention.
[0122] The mold 84 includes a first receiving section 84a for
receiving the first side shield 50A, a second receiving section 84b
for receiving the second side shield, and a midsection 84c located
between the first receiving section 84a and the second receiving
section 84b and forming a gap G between the first portion 40b1 and
the first gap layer 45. The first receiving section 84a, the second
receiving section 84b and the midsection 84c correspond to the
opening 84Pa, the opening 84Pb, and the initial midsection 84Pc of
the second resist layer 84P, respectively. The gap G is formed by
removing a portion of the separating film 83 lying under the
initial midsection 84Pc. Even if the gap G is formed, the mold 84
will not peel off because most part of the separating film 83 lying
under the mold 84 remains unremoved.
[0123] FIG. 17A and FIG. 17B show the next step. In this step, a
magnetic layer 50P is formed by plating, using the third layer 43
as a seed and an electrode. The magnetic layer 50P includes an
initial first side shield 50AP received in the first receiving
section 84a, an initial second side shield 50BP received in the
second receiving section 84b, and a coupling section 50CP lying in
the gap G and coupling the initial first side shield 50AP and the
initial second side shield 50BP to each other. The coupling section
50CP is formed by the material of the magnetic layer 50P getting
into the gap G (see FIG. 16A and FIG. 16B). The coupling section
50CP is interposed between the leading shield 40 and a region where
the main pole 52 is to be formed. Next, the mold 84 and the
separating film 83 are removed as shown in FIG. 18A and FIG.
18B.
[0124] FIG. 19A and FIG. 19B show the next step. In this step, the
coupling section 50CP is removed by etching the magnetic layer 50P
by, for example, ion beam etching, so that the initial first side
shield 50AP becomes the first side shield 50A and the initial
second side shield 50BP becomes the second side shield 50B. In this
step, the magnetic layer 50P may be over-etched such that the
etching in the region between the first side shield 50A and the
second side shield 50B terminates at the third layer 43 or the
second layer 42 of the leading shield 40. In this case, a part of
the third layer 43 lying between the coupling section 50CP before
etched and the second layer 42 may be completely removed.
[0125] FIG. 20A and FIG. 20B show the next step. In this step,
first, a mask (not illustrated) is formed to cover the first and
second side shields 50A and 50B. The mask is formed by patterning a
photoresist layer. Next, portions of the third layer 43 that are
not covered with the mask are removed by ion beam etching, for
example. The mask is then removed. Next, the second gap layer 46 is
formed over the entire top surface of the stack. A seed layer 85 is
then formed over the entire top surface of the stack. The seed
layer 85 is used as an electrode and a seed when forming the main
pole 52 by plating.
[0126] FIG. 21A and FIG. 21B show the next step. In this step,
first, a third resist layer 86 is formed on the stack. The third
resist layer 86 is formed such that its top surface is higher in
level than the top surfaces of portions of the seed layer 85 lying
on the first and second side shields 50A and 50B. The third resist
layer 86 has an opening 86a shaped to correspond to the shape of
the main pole 52 to be formed later. Next, an initial main pole
52P, which will later become the main pole 52, is formed in the
opening 86a of the third resist layer 86 by performing plating with
the seed layer 85 used as an electrode and a seed layer. The
initial main pole 52P is formed such that its top surface is higher
in level than the top surfaces of the portions of the seed layer 85
lying on the first and second side shields 50A and 50B.
[0127] FIG. 22A and FIG. 22B show the next step. In this step,
first, the third resist layer 86 is removed. Then, portions of the
second gap layer 46 and the seed layer 85 that are not covered with
the initial main pole 52P are removed by, for example, ion beam
etching using the initial main pole 52P as an etching mask.
[0128] FIG. 23A and FIG. 23B show the next step. In this step,
first, the nonmagnetic layer 53 is formed over the entire top
surface of the stack. The second gap layer 46, the initial main
pole 52P, the nonmagnetic layer 53 and the seed layer 85 are then
polished by, for example, CMP, until the first and second side
shields 50A and 50B are exposed.
[0129] FIG. 24A and FIG. 24B show the next step. In this step,
first, the nonmagnetic layer 54 is formed on the top surface of the
initial main pole 52P. Then, the first and side shields 50A and
50B, the initial main pole 52P, the second gap layer 46 and the
nonmagnetic layers 53 and 54 are taper-etched in part by, for
example, ion beam etching, so as to provide the top surface of the
initial main pole 52P with the first inclined portion 52T1 and
provide the nonmagnetic layer 54 with the end face mentioned
previously. This makes the initial main pole 52P into the main pole
52. A portion of the top surface of the initial main pole 52P that
remains after the etching makes the first flat portion 52T2. Next,
the third gap layer 60 is formed over the entire top surface of the
stack. Then, the fourth gap layer 61 is formed on the third gap
layer 60. The fourth gap layer 61 may be formed by a lift-off
process, or by first forming a nonmagnetic film on the third gap
layer 60 and then etching a portion of the nonmagnetic film.
[0130] Now, steps to follow the formation of the fourth gap layer
61 will be described with reference to FIG. 2 and FIG. 3. First,
the third and fourth gap layers 60 and 61 are selectively etched to
form therein three openings for exposing the top surfaces of the
first and second side shields 50A and 50B and the main pole 52.
Then, the trailing shield 62 is formed on the first and second side
shields 50A and 50B and the third and fourth gap layers 60 and 61,
and the first yoke layer 63 is formed on the main pole 52, by frame
plating, for example. Next, the insulating layer 64 is formed to
cover the trailing shield 62 and the first yoke layer 63. The
insulating layer 64 is then polished by, for example, CMP, until
the trailing shield 62 and the first yoke layer 63 are exposed.
[0131] Next, the insulating film 65 is formed over the entire top
surface of the stack. The coil 66 is then formed on the insulating
film 65 by frame plating, for example. Then, the insulating film 67
is formed to cover the coil 66. The insulating films 65 and 67 are
then selectively etched to form therein openings for exposing the
top surfaces of the trailing shield 62 and the first yoke layer 63.
Next, the second yoke layer 68 is formed on the trailing shield 62,
the first yoke layer 63 and the insulating film 67 by frame
plating, for example.
[0132] Next, the protective layer 69 is formed to cover the entire
top surface of the stack. Then, wiring, terminals and other
components are formed on the protective layer 69, the substrate 10
is cut near the imaginary plane ABS, the cut surface is polished to
form the medium facing surface 80, and processing such as
fabrication of flying rails is performed to complete the magnetic
head.
[0133] Now, a description will be given of the effect of the
manufacturing method for the magnetic head according to the
embodiment. The magnetic head manufactured by the manufacturing
method according to the embodiment allows reduction in the
occurrence of unwanted erasure and improvement of recording density
by virtue of the function of the write shield 110. In the
embodiment, the second gap layer 46 is interposed between the first
portion 40b1 of the top surface 40b of the leading shield 40 and
the third portion 52L11 of the bottom end 52L of the main pole 52,
whereas the first gap layer 45 is not interposed therebetween. On
the other hand, the first and second gap layers 45 and 46 are
interposed between the second portion 40b2 of the top surface 40b
of the leading shield 40 and the fourth portion 52L12 of the bottom
end 52L of the main pole 52. The embodiment thus makes it possible
to reduce leakage of magnetic flux from the main pole 52 to the
leading shield 40 by increasing the distance between the bottom end
52L of the main pole 52 and the top surface 40b of the leading
shield 40 at a location apart from the medium facing surface 80
through the use of the first and second gap layers 45 and 46, while
allowing the end face 52a of the main pole 52 and the leading
shield end face 40a to be at a desired distance from each other in
the medium facing surface 80 through the use of the second gap
layer 46.
[0134] If there exists a step between the third portion 52L11 and
the fourth portion 52L12 of the bottom end 52L, magnetic flux
becomes more likely to leak out of the main pole 52 at the boundary
between the third portion 52L11 and the fourth portion 52L12. In
the embodiment, there is no step between the third portion 52L11
and the fourth portion 52L12. The embodiment thus makes it possible
to reduce leakage of magnetic flux out of the main pole 52 when
compared with the case where there is a step between the third
portion 52L11 and the fourth portion 52L12.
[0135] In the embodiment, the third gap layer 60 is interposed
between the fifth portion 62b1 of the bottom surface 62b of the
trailing shield 62 and the seventh portion of the top surface 52T
of the main pole 52, whereas the fourth gap layer 61 is not
interposed therebetween. On the other hand, the third and fourth
gap layers 60 and 61 are interposed between the sixth portion 62b2
of the bottom surface 62b of the trailing shield 62 and the eighth
portion of the top surface 52T of the main pole 52. The embodiment
thus makes it possible to reduce leakage of magnetic flux from the
main pole 52 to the trailing shield 62 by increasing the distance
between the top surface 52T of the main pole 52 and the bottom
surface 62b of the trailing shield 62 at a location apart from the
medium facing surface 80 through the use of the third and fourth
gap layers 60 and 61, while allowing the end face 52a of the main
pole 52 and the trailing shield end face 62a to be at a desired
distance from each other in the medium facing surface 80 through
the use of the third gap layer 60.
[0136] In the manufacturing method according to the embodiment,
after the formation of the magnetic layer 50P including the
coupling section 50CP interposed between the leading shield 40 and
the region where the main pole 52 is to be formed, the mold 84 is
removed and then the coupling section 50CP is removed by etching
the magnetic layer 50P. The embodiment thus makes it possible to
prevent a volume reduction of the main pole 52 and degradation of
the write characteristics of the magnetic head attributable to the
coupling section 50CP.
[0137] The strength of the write magnetic field at or in the
vicinity of the top edge of the end face of the main pole, which
will hereinafter be referred to as the write field strength, and
the gradient of change in the write field strength in the track
width direction, which will hereinafter be referred to as the write
field gradient, are important characteristics of the write head
unit. The write field strength is connected with the write
characteristics of the magnetic field. The higher the write field
strength, the better the overwrite property. The write field
gradient is connected with the occurrence of unwanted erasure. The
larger the write field gradient, the greater the effect of reducing
the occurrence of unwanted erasure.
[0138] In typical magnetic heads, the write field strength and the
write field gradient are traded off. Now, a magnetic head of a
comparative example having the following structure will be
contemplated as an example of typical magnetic heads. The magnetic
head of the comparative example does not have the first gap layer
45. Further, in the magnetic head of the comparative example, the
top surface 40b of the leading shield 40 does not have the step
40b3, so that the first portion 40b1 and the second portion 40b2
are continuous with each other. The remainder of configuration of
the magnetic head of the comparative example is the same as that of
the magnetic head according to the embodiment.
[0139] The magnetic head of the comparative example is designed to
provide a write field gradient of a desired value. In this case,
the magnetic head of the comparative example cannot achieve a
sufficient increase in the value of the write field strength due to
the aforementioned relationship between the write field strength
and the write field gradient.
[0140] In contrast to the magnetic head of the comparative example,
the magnetic head according to the embodiment is able to reduce
leakage of magnetic flux from the main pole 52 to the leading
shield 40 without the need for changing the distance between the
end face 52a of the main pole 52 and the leading shield end face
40a and the distance between the end face 52a of the main pole 52
and each of the first and second side shield end faces 50Aa and
50Ba. Thus, in contrast to the magnetic head of the comparative
example, the magnetic head according to the embodiment is able to
make the write field strength noticeably higher without
necessitating much reduction in the write field gradient. In other
words, the magnetic head according to the embodiment is able to
provide a write field strength of a sufficiently large value, and
also able to prevent the occurrence of unwanted erasure.
[0141] In this embodiment, both of the distance from the medium
facing surface 80 to the step 40b3 and the height (the dimension in
the X direction) of the step 40b3 are connected with the write
field strength and the write field gradient. More specifically, in
the embodiment, as the distance from the medium facing surface 80
to the step 40b3 increases, the write field strength decreases
whereas the write field gradient increases. Further, as the height
of the step 40b3 increases, the write field strength increases
whereas the write field gradient decreases. Thus, in the
embodiment, the write field strength and the write field gradient
can be adjusted by controlling the distance from the medium facing
surface 80 to the step 40b3 and the height of the step 40b3.
[0142] In order for the magnetic head according to the embodiment
to achieve a noticeably higher write field strength with less
reduction in the write field gradient when compared with the
magnetic head of the comparative example, the distance from the
medium facing surface 80 to the step 40b3 preferably falls within
the range of 50 to 110 nm, and the height of the step 40b3
preferably falls within the range of 5 to 25 nm.
[0143] By virtue of the foregoing features, this embodiment allows
for manufacture of a magnetic head that is capable of preventing
the occurrence of unwanted erasure and is less prone to degradation
of write characteristics.
[0144] According to this embodiment, it is possible to adjust the
shape of the first and second side shields 50A and 50B by etching a
portion of each of the initial first side shield 50AP and the
initial second side shield 50BP when removing the coupling section
50CP. This serves to adjust the shape of the main pole 52. FIG. 25
is a cross-sectional view showing an example of the first and
second side shields 50A and 50B after the coupling section 50CP is
removed. In FIG. 25, the symbol SW1 denotes the first sidewall of
the first side shield 50A; the symbol SW2 denotes the second
sidewall of the second side shield 50B. In FIG. 25, the initial
first side shield 50AP and the initial second side shield 50BP
before etching are shown by broken lines. FIG. 25 shows an example
in which the magnetic layer 50P is over-etched in the step of
removing the coupling section 50CP such that the etching in the
region between the first side shield 50A and the second side shield
50B terminates at the second layer 52 of the leading shield 40.
[0145] In this embodiment, as shown in FIG. 25, etching a portion
of each of the initial first side shield 50A and the initial second
side shield 50BP allows for an increase in the angle formed by each
of the first and second sidewalls SW1 and SW2 with respect to a
direction perpendicular to the top surface of the substrate 10.
This makes it possible to increase the angle (hereinafter referred
to as the inclination angle) formed by each of the first and second
side surfaces Si and S2 of the main pole 52 with respect to the
direction perpendicular to the top surface of the substrate 10.
Given the same length (dimension in the X direction) of the top
edge of the end face 52a of the main pole 52, an increase in the
inclination angle can reduce the height (dimension in the Z
direction) of the end face 52a of the main pole 52. This serves to
enhance the effect of reducing the occurrence of unwanted erasure
caused by a skew.
[0146] Further, as shown in FIG. 25, by etching a portion of each
of the initial first side shield 50AP, the initial second side
shield 50BP and the leading shield 40, the bottom of the groove
formed in the leading shield 40 by the etching becomes smaller in
width (dimension in the X direction) than the minimum distance
between the first sidewall SW1 and the second sidewall SW2. This
allows for a reduction in the length (dimension in the X direction)
of the bottom edge of the end face 52a of the main pole 52.
[0147] The present invention is not limited to the foregoing
embodiment, and various modifications may be made thereto. For
example, as far as the requirements of the appended claims are met,
the shapes and locations of the main pole 52, the write shield 110
and the gap section 120 can be freely chosen without being limited
to the examples illustrated in the foregoing embodiment. For
example, a portion of the gap section 120 that separates the
leading shield 40 from the bottom end 52L of the main pole 52 may
be constituted by three or more nonmagnetic layers including the
first and second gap layers 45 and 46. Likewise, a portion of the
gap section 120 that separates the trailing shield 62 from the top
surface 52T of the main pole 52 may be constituted by three or more
nonmagnetic layers including the third and fourth gap layers 60 and
61.
[0148] Obviously, many modifications and variations of the present
invention are possible in the light of the above teachings. Thus,
it is to be understood that, within the scope of the appended
claims and equivalents thereof, the invention may be practiced in
other than the foregoing most preferable embodiment.
* * * * *