U.S. patent application number 12/331079 was filed with the patent office on 2009-06-18 for method for manufacturing magnetic head.
This patent application is currently assigned to FUJITSU LIMITED. Invention is credited to Takashi Ito, Masaya Kato, Hiroyuki Miyazawa, Masanori Tachibana.
Application Number | 20090152119 12/331079 |
Document ID | / |
Family ID | 40751783 |
Filed Date | 2009-06-18 |
United States Patent
Application |
20090152119 |
Kind Code |
A1 |
Tachibana; Masanori ; et
al. |
June 18, 2009 |
METHOD FOR MANUFACTURING MAGNETIC HEAD
Abstract
According to an aspect of an embodiment, a method for
manufacturing a magnetic head includes: providing a substrate;
forming a first magnetic layer having a pattern for forming a
magnetic pole on the substrate; forming a stopper layer of
non-magnetic material on the top and the sides of the first
magnetic layer; reducing the thickness of the stopper layer on the
top of the first magnetic layer; and forming a second magnetic
layer on the stopper layer. The method further includes: polishing
the second magnetic layer to expose the stopper layer on the top of
the first magnetic layer; and removing the stopper layer on the top
of the first magnetic layer, so as to expose the top of the first
magnetic layer.
Inventors: |
Tachibana; Masanori;
(Kawasaki, JP) ; Kato; Masaya; (Kawasaki, JP)
; Ito; Takashi; (Kawasaki, JP) ; Miyazawa;
Hiroyuki; (Kawasaki, JP) |
Correspondence
Address: |
GREER, BURNS & CRAIN
300 S WACKER DR, 25TH FLOOR
CHICAGO
IL
60606
US
|
Assignee: |
FUJITSU LIMITED
Kawasaki-shi
JP
|
Family ID: |
40751783 |
Appl. No.: |
12/331079 |
Filed: |
December 9, 2008 |
Current U.S.
Class: |
205/127 ;
205/222 |
Current CPC
Class: |
C23C 28/023 20130101;
G11B 5/1278 20130101; C25D 5/12 20130101; C25D 5/52 20130101; C25D
5/022 20130101; G11B 5/315 20130101; G11B 5/3163 20130101 |
Class at
Publication: |
205/127 ;
205/222 |
International
Class: |
C25D 5/02 20060101
C25D005/02; C25D 5/52 20060101 C25D005/52 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 14, 2007 |
JP |
2007322674 |
Claims
1. A method for manufacturing a magnetic head comprising: providing
a substrate; forming a first magnetic layer having a pattern for
forming a magnetic pole on the substrate; forming a stopper layer
of non-magnetic material on the top and the sides of the first
magnetic layer; reducing the thickness of the stopper layer on the
top of the first magnetic layer; forming a second magnetic layer on
the stopper layer; polishing the second magnetic layer to expose
the stopper layer on the top of the first magnetic layer; and
removing the stopper layer on the top of the first magnetic layer,
so as to expose the top of the first magnetic layer.
2. The method according to claim 1, wherein the stopper is formed
of tantalum.
3. The method according to claim 1, wherein forming the first
magnetic layer includes: forming a plating seed layer on the
substrate; forming a resist pattern on the plating seed layer, the
resist pattern having an opening in which the plating seed layer is
exposed at the bottom; and electroplating by using the plating seed
layer as a plating power supply layer so as to form the first
magnetic layer on a part of the plating seed layer in the
opening.
4. The method according to claim 1, further comprising: etching the
upper side of the substrate by using the first magnetic layer as a
mask.
5. The method according to claim 3, further comprising: etching the
plating seed layer by using the first magnetic layer as a mask
after forming the first magnetic layer.
6. The method according to claim 5, further comprising: etching the
upper side of the substrate by using the first magnetic layer as a
mask.
7. The method according to claim 1, further comprising: polishing
the surface of the substrate to finish the surface after removing
the stopper layer.
8. The method according to claim 1, further comprising: forming on
the stopper layer a resist pattern having an opening exposing a
part of the stopper layer where the first magnetic layer is
disposed, wherein the second magnetic layer is formed on the part
of the stopper layer in the opening; and removing the resist
pattern after forming the second magnetic layer.
9. The method according to claim 1, further comprising: forming an
insulating layer on the second magnetic layer, wherein by polishing
the second magnetic layer, the insulating layer is polished
simultaneously with the second magnetic layer to form a common
plane.
10. A method for manufacturing a magnetic head comprising:
providing a substrate; forming a first magnetic layer having a
pattern for forming a magnetic pole on the substrate on the
substrate; forming a stopper layer of non-magnetic material on the
top of the first magnetic layer; forming a first insulating layer
on the top of the stopper layer and the sides of the first magnetic
layer, the first insulating layer capable of being polished at a
higher rate than the stopper layer; reducing the thickness of the
first insulating layer on the top of the stopper layer formed on
the top of the first magnetic layer; forming a second magnetic
layer on the stopper layer; polishing the second magnetic layer to
expose the stopper layer on the top of the first magnetic layer;
and removing the stopper layer on the top of the first magnetic
layer, so as to expose the top of the first magnetic layer.
11. The method according to claim 10, wherein the first insulating
layer is formed of alumina.
12. The method according to claim 10, wherein the stopper is formed
of tantalum.
13. The method according to claim 10, wherein forming the first
magnetic layer includes: forming a plating seed layer on the
substrate; forming a resist pattern on the plating seed layer, the
resist pattern having an opening in which a part of the plating
seed layer is exposed; and electroplating by using the plating seed
layer as a plating power supply layer so as to form the first
magnetic layer on a part of the plating seed layer in the
opening.
14. The method according to claim 10, wherein the stopper layer of
non-magnetic material is further formed on the side of the first
magnetic layer.
15. The method according to claim 10, further comprising: etching
the upper side of the substrate by using the first magnetic layer
as a mask.
16. The method according to claim 13, further comprising: etching
the plating seed layer by using the first magnetic layer as a mask
after forming the first magnetic layer.
17. The method according to claim 16, further comprising: etching
the upper side of the substrate by using the first magnetic layer
as a mask.
18. The method according to claim 10, further comprising: polishing
the surface of the substrate to finish the surface after removing
the stopper layer.
19. The method according to claim 10, further comprising: forming
on the stopper layer a resist pattern having an opening exposing a
part of the stopper layer where the first magnetic layer is
disposed, wherein the second magnetic layer is formed on the part
of the stopper layer in the opening; and removing the resist
pattern after forming the second magnetic layer.
20. The method according to claim 10, further comprising: forming a
second insulating layer wherein by polishing the second magnetic
layer, the second insulating layer is polished simultaneously with
the second magnetic layer to form a common plane.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from the prior Japanese Patent Application No. 2007-322674
filed on Dec. 14, 2007, the entire content of which is incorporated
herein by reference.
BACKGROUND
[0002] 1. Field
[0003] This art relates to magnetic heads for writing information
on recording media.
[0004] 2. Description of the Related Art
[0005] In magnetic heads used in magnetic disk devices, the skew
angle is varied depending on whether the arm supporting the
magnetic head lies at the inner periphery side or at the outer
periphery side of the recording medium.
[0006] This causes the so-called side track erase problem that
information written in the adjacent track is erased, or that the SN
ratio of the magnetic recording is reduced. In order to prevent the
side track erase problem, the recording magnetic pole has an
inverted trapezoidal end face.
[0007] As the recording density of recording media is increased,
however, the side erase problem becomes noticeably occurring.
Accordingly, techniques have been proposed in which side shields
are disposed with the magnetic pole in between to prevent the
magnetic flux from leaking to the adjacent tracks (Japanese
Laid-open Patent Publications No. 2007-52904, No. 2007-35082, and
No. 2007-257742).
SUMMARY
[0008] According to an aspect of an embodiment, a method for
manufacturing a magnetic head includes: providing a substrate;
forming a first magnetic layer having a pattern for forming a
magnetic pole on the substrate; forming a stopper layer of
non-magnetic material on the top and the sides of the first
magnetic layer; reducing the thickness of the stopper layer on the
top of the first magnetic layer; forming a second magnetic layer on
the stopper layer; polishing the second magnetic layer to expose
the stopper layer on the top of the first magnetic layer; and
removing the stopper layer on the top of the first magnetic layer,
so as to expose the top of the first magnetic layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIGS. 1A to 1C are side views and a plan view of the
structure of a main magnetic pole and a trailing shield;
[0010] FIGS. 2A to 2D are representations of a process up to the
step of forming a first magnetic layer;
[0011] FIGS. 3A to 3E are representations of a process up to the
step of forming a second magnetic layer;
[0012] FIGS. 4A to 4E are representations of a process up to the
step of forming a main magnetic pole and side shields;
[0013] FIGS. 5A to 5F are representations of a process up to the
step of forming a trailing shield, following the formation of the
main magnetic pole and the side shields;
[0014] FIGS. 6A to 6D are representations of a modification of the
first embodiment;
[0015] FIGS. 7A to 7F are representations of a manufacturing method
according to a second embodiment; and
[0016] FIGS. 8A to 8E are representation of a modification of the
second embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] FIGS. 1A to 1C are schematic views of the structure of a
recording head including side shields.
[0018] FIGS. 1A and 1B show the recording head when viewed from the
flying side. This recording head is of perpendicular magnetic
recording type. Side shields 12a and 12b are disposed at both sides
of an inverted trapezoidal main magnetic pole 10, and a trailing
shield 14 is disposed over the main magnetic pole 10 and the side
shields 12a and 12b. The spaces among the main magnetic pole 10,
side shields 12a and 12b, and the trailing shield 14 are filled
with an insulating material, such as Al.sub.2O.sub.3 or SiO.sub.2,
or a non-magnetic metal, such as Ta. FIG. 1C is a plan view of the
recording head. The main magnetic pole 10 has a narrow end portion
having a small width at the ABS (Air-Bearing Surface) side and the
width gradually increases in the height direction. The side shields
12a and 12b are disposed at both sides of the narrow end portion of
the magnetic pole.
[0019] In order to form the main magnetic pole 10 of a recording
head, for example, a substrate is coated with a resist layer, and
the resist layer is patterned so as to form an opening
corresponding to the shape of the main magnetic pole. A magnetic
material is deposited to raise the level in the opening by plating.
Thus, a main magnetic pole is formed. Since the upper surface of
the deposition of the magnetic material in the opening is curved,
the upper surface is polished to planarize so that the narrow end
portion of the magnetic pole can be formed in an inverted
trapezoidal shape.
[0020] The recording accuracy is significantly affected by the
shape of the end face of the main magnetic pole. It is therefore
desirable that the main magnetic pole be formed with a proper
height (thickness) and core width. An extremely large number of
magnetic heads are formed in a substrate. For forming main magnetic
poles having a desired shape in the substrate by polishing, the
manufacturing process must be carefully performed so that highly
precise working can be achieved.
[0021] When the side shields are formed in addition to the main
magnetic pole, the side shields must be reliably formed without
degrading the accuracy in the formation of the main magnetic
pole.
[0022] Preferred embodiments will now be described in detail with
reference to the drawings.
First Embodiment
[0023] FIGS. 2A to 5F are representations of a method for
manufacturing a magnetic head according to a first embodiment,
showing steps for forming a main magnetic pole of a perpendicular
magnetic head and side shields disposed with the main magnetic pole
in between.
Forming a First Magnetic Layer
[0024] FIGS. 2A to 2D are representation of a process up to the
step of forming a first magnetic layer 23 intended for the main
magnetic pole on the surface of a substrate. The substrate has a
read head including a read element.
[0025] FIG. 2A shows the state in which a plating seed layer 21 has
been formed of, for example, ruthenium on a base layer 20 formed on
the surface of the substrate by sputtering.
[0026] Then, a resist pattern 22 is formed on the surface of the
plating seed layer 21 (FIG. 2B). For forming the resist pattern 22,
the surface of the plating seed layer 21 is coated with a resist
layer. The resist layer is exposed to light corresponding to a
pattern of the main magnetic poles to be formed on the substrate,
and is subsequently developed to form an opening (a groove) 22a in
which the plating seed layer 21 is exposed at the bottom. FIG. 2B
shows the opening 22a formed in the resist pattern 22 viewed from
the side of the region in which the narrow end of the main magnetic
pole will be formed.
[0027] Since the narrow end of the main magnetic pole is formed in
an inverted trapezoidal shape, the region in the opening 22a in
which the narrow end of the main magnetic pole will be formed is
formed in an inverted trapezoidal shape in sectional view. After
exposure and development of the resist layer, the open side of the
opening 22a is expanded to have a larger width than the bottom side
through a heating step. Thus, the opening 22a has an inverted
trapezoidal section, having an inclined inner wall.
[0028] FIGS. 2A to 2D show one of the openings 22a formed in the
resist pattern 22. Many magnetic heads will be formed in the
substrate. The resist pattern 22 is formed corresponding to the
pattern of the main magnetic poles in the regions where magnetic
heads will be formed.
[0029] Then, a first magnetic layer 23 is deposited to raise the
level in the opening 22a of the resist pattern 22 by electroplating
using the plating seed layer 21 as a plating power supply layer
(FIG. 2C). The main magnetic pole has superior soft magnetic
characteristics, and is formed of a magnetic material having a high
saturation magnetic flux density, such as NiFe or FeCo.
[0030] Then, the resist pattern 22 is removed to form the first
magnetic layer 23 intended for the main magnetic pole on the
surface of the plating seed layer 21 (FIG. 2D).
Forming a Second Magnetic Layer
[0031] FIGS. 3A to 3E show a process up to the step of forming a
second magnetic layer intended for side shields.
[0032] FIG. 3A shows the state in which a stopper layer 24 has been
formed. The stopper layer 24 defines side gaps and positions
subjected to polishing. A stopper material is deposited on the top
and side surfaces the first magnetic layer 23 by sputtering in a
slanted direction with respect to the surface of the substrate.
[0033] Preferably, the material of the stopper layer 24 is a
non-magnetic material that can favorably act as a polishing
stopper, such as Ta (tantalum).
[0034] The thickness of the stopper material coating the side
surfaces of the first magnetic layer 23 near the narrow end defines
the interval D of the side gap. The side gap can be therefore
controlled by adjusting the sputtering conditions.
[0035] FIG. 3B shows the step of reducing the thickness of the
stopper layer 24 on the top of the first magnetic layer 23 by ion
milling. In the following step, the surface of the substrate is
polished to planarize. This polishing step is performed up to the
vicinity of the top of the first magnetic layer 23. Accordingly, in
order to ensure the polishing step, the stopper layer 24 coating
the top of the first magnetic layer 23 is formed to a small
thickness that can maintain its function as a stopper in the
polishing step, and to a thickness of, for example, 80 nm. The
thickness of the stopper layer 24 on the top of the first magnetic
layer 23 can be reduced without varying the thickness of the
stopper material coating the side surfaces of the first magnetic
layer 23, or the interval D of the side gap, by controlling the
conditions of ion milling performed on the surface of the
substrate.
[0036] In the step of reducing the thickness of the stopper layer
24, the surface of the stopper layer 24 directly exposed to the
milling ions at portions adjacent to the first magnetic layer 23 is
etched simultaneously, the thickness of the stopper layer 24
directly exposed to the milling ions at portions adjacent to the
first magnetic layer 23 being reduced. The etching of the surface
causes the first magnetic layer 23 to be covered with the side
shields widely. In a magnetic disk device having the magnetic head
according to the embodiment and a magnetic disk, the side shields
effectively prevent the magnetic flux from leaking to the adjacent
tracks adjacent to the track where magnetic information is to be
written during writing operations. Consequently it is highly
unlikely that the side track erase is caused. The larger the
interval D of the side gap is, the more effectively the step of
reducing the thickness of the stopper layer 24 contributes to
preventing the side track erase.
[0037] Then, a plating base 25 is formed over the entire surface of
the substrate by sputtering (FIG. 3C). The plating base 25 is made
of a magnetic metal, such as NiFe or CoNiFe, or a non-magnetic
metal, such as ruthenium or copper. Preferably, the plating base 25
is formed of the same material as the material deposited by
electroplating.
[0038] Then, the surface of the substrate coated with the plating
base 25 is further coated with a resist layer. The resist layer is
exposed to light and developed to form a resist pattern 26 having
an opening (a groove) 26a at the sides of the narrow end of the
first magnetic layer 23 (FIG. 3D). Consequently, the plating base
25 is exposed at the bottom of the opening 26a. In the opening 26a,
a magnetic layer intended for the side shields is formed at the
sides of the main magnetic pole.
[0039] The side shields are formed in practice so as to extend to
the positions quite distant (about 1 to 25 .mu.m) from the sides of
the main magnetic pole. Although FIGS. 3D and 3E show the opening
26a whose side walls are not much distant from the first magnetic
layer 23, the opening 26a is formed in practice so that the side
shields can extend to positions quite distant from the first
magnetic layer 23. The same applies to the figures showing the side
shields of other embodiments, and the transverse direction of such
figures is shown with a smaller scale.
[0040] Then, a second magnetic layer 27 is deposited to raise the
level in the opening 26a by electroplating using the plating base
25 as a plating power supply layer (FIG. 3E). The second magnetic
layer 27 is formed so as to fill the opening 26a on a part of the
stopper layer 24 at the sides of the first magnetic layer 23.
[0041] The second magnetic layer 27 is intended for the side
shields. A soft magnetic material having superior shielding
properties, such as NiFe, can be used for the second magnetic layer
27. The stopper layer 24 is formed of a material that can be
polished at a lower rate (more difficult to polish) than the
magnetic material of the second magnetic layer 27. In other words,
the second magnetic layer 27 is formed of a magnetic material that
can be polished at a higher rate than the stopper layer 24.
Polishing the Second Magnetic Layer
[0042] FIGS. 4A to 4E show a process up to the step of polishing
the second magnetic layer 27 coating the surface of the substrate
to form the side shields.
[0043] FIG. 4A shows the state in which the resist pattern 26 has
been removed. The resist pattern 26 can be removed by use of an
organic solvent or by dry etching.
[0044] In the step shown in FIG. 4B, the plating base 25 outside
the region coated with the second magnetic layer 27 is removed. The
removal of the plating base 25 can be performed by ion milling.
[0045] FIG. 4C shows the state in which the second magnetic layer
27 has been coated with an insulating layer 28 to fill the recesses
at the sides of the second magnetic layer 27 with the insulating
material. The insulating layer 28 is formed of an insulating a
material, such as alumina, by sputtering. The second magnetic layer
27 protrudes from the portion under which the first magnetic layer
23 is disposed. Accordingly, the insulating layer 28 has an uneven
surface by sputtering the surface of the substrate with an
insulating material.
[0046] Subsequently, the surface of the substrate is subjected to a
first polishing step. In the first polishing step, the insulating
layer 28 and the second magnetic layer 27 are polished to planarize
the surface of the substrate. The first polishing step can be
performed by CMP (Chemical Mechanical Polishing).
[0047] FIG. 4D shows the state in which the surface of the
substrate has been planarized by the first polishing step. In the
first polishing step, the stopper layer 24 coating the top of the
first magnetic layer 23 serves as a polishing stopper and stops the
progress of polishing when the stopper layer 24 on the top of the
first magnetic layer 23 is exposed. Consequently, the surfaces of
the second magnetic layer 27 and the insulating layer 28 disposed
at the sides of the second magnetic layer 27 become flush with each
other with the stopper layer 24 partially exposed at the surface of
the substrate.
[0048] FIG. 4E shows the state in which the top portion of the
stopper layer 24 coating the first magnetic layer 23 has been
removed so that the first magnetic layer 23 can be formed into an
inverted trapezoidal shape. The stopper layer 24 can be selectively
removed by reactive ion etching (RIE).
Forming Side Shields
[0049] FIGS. 5A to 5F show a process up to the step of forming a
trailing shield after a second polishing step of polishing the
surface of the substrate to form the main magnetic pole and side
shields.
[0050] FIG. 5A shows the state in which the surface of the
substrate has been subjected to the second polishing step to
planarize the surface. Since the stopper layer 24 has been removed
from the top of the first magnetic layer 23 in the preceding step,
the second polishing step polishes the first magnetic layer 23 from
the top side and thus forms the narrow end of the main magnetic
pole 23a in an inverted trapezoidal shape. The first polishing step
roughly planarizes the entire surface of the substrate, and the
second polishing step finishes the surface while the amount of
polishing is controlled. Thus, highly precise polishing can be
performed, and, consequently, each main magnetic pole of the
magnetic heads formed on the substrate is finished to a desired
shape.
[0051] In FIG. 5A, the side shields 27a formed by polishing the
upper surface of the second magnetic layer 27 are disposed with the
inverted trapezoidal narrow end of the main magnetic pole 23a in
between, and the stopper layer 24 made of an non-magnetic material
is disposed between the sides of the main magnetic pole 23a and
side shields 27a so that the main magnetic pole 23a is apart from
the side shields 27a with a predetermined distance.
[0052] FIG. 5B shows the state in which a non-magnetic layer 29 has
been formed of an insulating material, such as alumina, or a
non-magnetic metal by sputtering so that the trailing shield can be
formed over the main magnetic pole 23a with a distance. The
non-magnetic layer 29 defines a gap between the main magnetic pole
23a and the trailing shield, and is formed to a thickness of about
60 nm or less. Since the surface of the substrate is planarized,
the non-magnetic layer 29 can be formed to a uniform thickness over
the surface of the substrate. This technique can precisely form a
gap.
[0053] FIG. 5C shows the state in which a resist pattern 30 has
been formed on the surface of the substrate so that the
non-magnetic layer 29 can be left corresponding to the region where
the trailing shield will be formed.
[0054] Then, the surface of the substrate is subjected to ion
milling through the resist pattern 30 as a mask to remove the
portion of the non-magnetic layer 29 exposed at the surface of the
substrate. FIG. 6D shows the state after removing the resist
pattern 30.
[0055] Then, the trailing shield is formed by electroplating, as
shown in FIGS. 5E and 5F. In FIG. 5E, a plating seed layer 31 is
formed on the surface of the substrate, and then a resist pattern
32 is formed on the surface of the plating seed layer 31. The
resist pattern has an opening 32a in the region where the trailing
shield will be formed.
[0056] In FIG. 5F, a magnetic material is deposited in the opening
32a of the resist pattern 32 to form the trailing shield 34 by
electroplating using the plating seed layer 31 as a plating power
supply layer. Subsequently, after removing the resist pattern 32,
the portion of the plating seed layer 31 exposed at the surface of
the substrate is removed.
[0057] A return yoke is formed on the trailing shield 34. After the
step shown in FIG. 5F, the surface of the substrate is coated with
an insulating material, such as alumina, so as to dispose the
insulating material between the layers, followed by polishing to
planarize the surface of the substrate. Then, the return yoke is
formed so as to join to the trailing shield 34.
[0058] Thus, a read head is completed which includes the side
shields 27a disposed with the inverted trapezoidal narrow end of
the magnetic pole 23a in between, and the trailing shield 34 over
the main magnetic pole 23a with a predetermined distance.
[0059] In the magnetic head produced in practice, the side shields
27a extend to positions quite distant from the main magnetic pole
23a, unlike the structure shown in FIG. 5F, as mentioned above.
Also, the trailing shield 34 has a larger thickness than the state
shown in FIG. 5F.
Modification
[0060] FIGS. 6A to 6D show a modification of the method for
manufacturing a magnetic head according to the first embodiment.
FIG. 6A shows the step of forming the first magnetic layer 23 shown
in FIG. 2C. In the first embodiment, the first magnetic layer 23 is
formed corresponding to the shape of the section of the narrow end
of the main magnetic pole. On the other hand, in this modification,
the first magnetic layer 23 is formed into a shape having a larger
section than that of the narrow end of the main magnetic pole by a
polishing allowance for ion milling.
[0061] FIG. 6B shows the following step in which the substrate is
subjected to ion milling to etch the first magnetic layer 23 in
such a manner that the narrow end of the main magnetic pole has an
inverted trapezoidal section. In the ion milling step, the first
magnetic layer 23 is etched into a desired shape of the main
magnetic pole, and simultaneously the surface of the substrate is
polished so as to remove part of the plating seed layer 21 or the
entire plating seed layer and part of the base layer 20 at the
sides of the first magnetic layer 23.
[0062] FIG. 6C shows the state in which not only the plating seed
layer 21, but also part of the base layer 20 has been removed.
[0063] In this method, the first magnetic layer 23 is formed into a
desired shape of the main magnetic pole by ion milling. In
addition, this method allows the underlying layer of the first
magnetic layer 23 to be etched to the level lower than the bottom
of the first magnetic layer 23.
[0064] By etching the plating seed layer 21 or further etching the
base layer 20 at the sides of the first magnetic layer 23 to the
level lower than the bottom of the first magnetic layer 23, the
side shields 27a, which are formed in a subsequent step, can shield
the entire main magnetic pole 23a in the height direction
(thickness direction).
[0065] FIG. 6D shows the state in which the main magnetic pole 23a
and the side shields 27a have been formed through completely the
same steps shown in FIGS. 4A to 4E and 5A to 5F after the step
shown in FIG. 6C.
[0066] Since the plating seed layer 21 and the base layer 20 are
etched to a level lower than the bottom of the first magnetic layer
23, the bottoms of the side shields 27a lie below the bottom of the
main magnetic pole 23a and the sides of the main magnetic pole 23a
are covered with the side shields 27a. The positional relationship
between the side shields 27a and the main magnetic pole 23a is
clearly different from that shown in FIG. 5F.
[0067] By shielding the sides of the main magnetic pole 23a
including the portion around the bottom by the side shields 27a, as
described above, the recording magnetic pole can be shielded on the
sides effectively.
Second Embodiment
[0068] In the first embodiment, a side gap layer is formed by
sputtering a single stopper material after forming the first
magnetic layer 23, as shown in FIGS. 3A and 3B, so that the side
gap layer can serve as a polishing stopper. In the magnetic head
manufacturing method shown in FIGS. 7A to 7F, the stopper layer and
the side gap layer are formed of respective materials.
[0069] FIG. 7A shows the state in which a stopper layer 24a has
been formed to a thickness sufficient to act as a polishing stopper
on the top of the first magnetic layer 23. The stopper layer 24a is
formed of a stopper material, such as Ta, by sputtering. The
sputtering step deposits the stopper material on the top and side
surfaces of the first magnetic layer 23. The thickness of the
stopper layer 24a on the sides of the first magnetic layer 23 is
smaller than that on the top of the first magnetic layer 23. The
stopper layer 24a on the side surfaces of the first magnetic layer
23 defines part of the side gap layer.
[0070] FIGS. 7B and 7C show the step of forming a first insulating
layer 24b on the sides of the first magnetic layer 23. The first
insulating layer 24b defines a side gap layer together with the
stopper layer 24a formed on the sides of the first magnetic layer
23 in the preceding step. The first insulating layer 24b is formed
by sputtering an insulating material, such as alumina, onto the
surface of the substrate.
[0071] FIG. 7B shows the state in which the first insulating layer
24b has coated the surface of the stopper layer 24a including the
portions on the sides of the first magnetic layer 23. Since the
thicknesses of the stopper layer 24a on the side surfaces of the
first magnetic layer 23 and the first insulating layer 24b coating
the side surfaces of the stopper layer 24a define the side gap, the
thickness of the first insulating layer 24b is controlled so that
the entire side gap layer form a predetermined side gap.
[0072] Then, the surface of the substrate is subjected to ion
milling to remove the first insulating layer 24b coating the top of
the first magnetic layer 23 until the stopper layer 24a is exposed
(FIG. 7C). In this instance, the first insulating layer 24b is not
necessarily removed so as to expose the entire surface of the
stopper layer 24a, and part of the first insulating layer 24b may
be left. The material of the first insulating layer 24b is selected
from the materials that can be polished at a higher rate (easier to
polish) than the stopper material of the stopper layer 24a.
Preferably, the surface of the stopper layer 24a is exposed in the
step shown in FIG. 7C, so that the subsequent polishing can be
performed precisely.
[0073] Then, a plating base 25 is formed over the entire surface of
the substrate by sputtering. FIG. 7D shows the state in which the
plating base layer 25 has been formed over the surface of the
substrate.
[0074] After forming the plating base 25, the same steps as in the
first embodiment are performed.
[0075] FIG. 7E shows the state in which a second magnetic layer 27
has been formed in an opening 26a of a resist pattern 26 formed on
the surface of the substrate, by electroplating using the plating
base 25 as the plating power supply layer. Then, the resist pattern
26 is removed, and the surface of the substrate is coated with a
second insulating layer made of an insulating material, such as
alumina, to planarize the surface of the substrate. Thus, the main
magnetic pole 23a and the side shields 27a are completed.
[0076] In the present embodiment as well, the surface of the
substrate is planarized by the first polishing step to a height at
which the surface of the stopper layer 24a is exposed. The top of
the stopper layer 24a is selectively removed by RIE, and thus, the
main magnetic pole 23a and the side shields 27a are formed. FIG. 7F
shows the state in which a trailing shield 34 has been formed after
the formation of the main magnetic pole 23a and the side shields
27a. In the present embodiment, a gap is formed between the side
shields 27a and the trailing shield 34, using a non-magnetic layer
29.
Modification
[0077] FIGS. 8A to 8E show a modification of the method for
manufacturing a magnetic head according to the second embodiment.
In the step shown in FIG. 8A, the first magnetic layer 23 is
formed, and then, ion milling is performed using the first magnetic
layer 23 as a mask so that the narrow end of the first magnetic
layer 23 is etched into a desired inverted trapezoidal shape and so
that the plating seed layer 21 at the sides of the first magnetic
layer 23 or the plating seed layer 21 and part of the base layer 20
below the first magnetic layer 23 are etched to a level lower than
the bottom of the first magnetic layer 23, in the same manner as in
the steps shown in FIGS. 6A to 6D.
[0078] FIG. 8B shows the state in which the top of the first
magnetic layer 23 has been coated with a stopper layer 24a. The
side surfaces of the first magnetic layer 23 are also coated with
the stopper layer 24a with a small thickness. FIG. 8C shows the
state in which ion milling is performed on the surface of substrate
after forming a first insulating layer 24b defining the side gap
together with the stopper layer 24a coating the side surfaces of
the first magnetic layer 23.
[0079] FIG. 8D shows the state in which the first insulating layer
24b coating the top of the first magnetic layer 23 has been removed
to expose the stopper layer 24a by ion milling. The steps shown in
FIGS. 8B to 8D are performed in the same manner as the steps shown
in FIGS. 7A to 7C.
[0080] The following steps are performed in completely the same
manner as the steps shown in FIGS. 7D to 7F, and thus a read head
having side shields 27a at the sides of the main magnetic pole 23a
is completed (FIG. 8E).
[0081] In the read head of the present modification, the bottoms of
the side shields 27a lie below the bottom of the main magnetic pole
23a and the side surfaces of the main magnetic pole 23a are covered
with the side shields 27a entirely in the height direction.
Consequently, the magnetic pole can be shielded effectively by the
side shields 27a.
[0082] In the magnetic head manufacturing method according to the
present embodiment, a recording magnetic pole having side shields
can be precisely formed in a desired shape with the distances
between the side shields and the magnetic pole controlled. In
particular, even in a process manufacturing an extremely large
number of magnetic heads on a wafer, the end face of the main
magnetic pole of each magnetic head can be precisely formed by, for
example, polishing a structure in which the top of the first
magnetic layer is coated with a stopper layer.
[0083] Since in the method according to the embodiments, the side
gaps and the gap between the main magnetic pole and the trailing
shield are formed in different steps, each gap can be formed
precisely.
[0084] Since the method according to the embodiments has the step
of reducing the thickness of the stopper layer, the first magnetic
layer is covered with the side shields widely. In a magnetic disk
device having the magnetic head according to the embodiment and a
magnetic disk, the side shields effectively prevent the magnetic
flux from leaking to adjacent tracks adjacent to the track where
magnetic information is to be written during writing operations.
Consequently it is highly unlikely that the side track erase is
caused.
[0085] While the above described embodiments illustrate methods for
manufacturing a perpendicular magnetic head including a main
magnetic pole, an another embodiment may be applied to methods for
manufacturing longitudinal magnetic heads.
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