U.S. patent application number 09/887263 was filed with the patent office on 2002-08-08 for thin film magnetic head and method of manufacturng same.
This patent application is currently assigned to TDK CORPORATION. Invention is credited to Sasaki, Yoshitaka.
Application Number | 20020105756 09/887263 |
Document ID | / |
Family ID | 26521282 |
Filed Date | 2002-08-08 |
United States Patent
Application |
20020105756 |
Kind Code |
A1 |
Sasaki, Yoshitaka |
August 8, 2002 |
Thin film magnetic head and method of manufacturng same
Abstract
A thin-film magnetic head and a method of manufacturing the same
in which a precise control of a pole width can be performed and, at
the same time, a sufficient overwrite characteristic can be
obtained is provided. A top pole includes a top area defining a
track width, a middle area coupled to the top area and a yolk area
coupled to the middle area. Positions of coupling point of the
middle area and the top area are met with throat height 0 position
which is a reference point of throat height. In the coupling point,
a step in the width direction with almost a right angle is
provided. A width of the middle area is made sufficiently wider
than a width of the top area in the coupling point.. Widening a
pattern width of photoresist for forming the top area can be
prevented and micronizing a recording track width is made possible.
Saturation of a magnetic flux occurred in the yolk area before
reaching the top area can be prevented and a sufficient overwrite
characteristic can be obtained for having the middle area with wide
width.
Inventors: |
Sasaki, Yoshitaka;
(Yokohama-shi, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. Box 19928
Alexandria
VA
22320
US
|
Assignee: |
TDK CORPORATION
|
Family ID: |
26521282 |
Appl. No.: |
09/887263 |
Filed: |
June 25, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09887263 |
Jun 25, 2001 |
|
|
|
09192284 |
Nov 16, 1998 |
|
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Current U.S.
Class: |
360/123.47 ;
360/123.44; 360/123.52; G9B/5.082; G9B/5.086; G9B/5.094 |
Current CPC
Class: |
Y10T 29/49044 20150115;
G11B 5/313 20130101; Y10T 29/49046 20150115; G11B 5/3163 20130101;
G11B 5/3116 20130101 |
Class at
Publication: |
360/126 |
International
Class: |
G11B 005/147 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 30, 1998 |
JP |
10-216177 |
Nov 11, 1998 |
JP |
10-320963 |
Claims
What is claimed is:
1. A thin-film magnetic head including: at least two magnetic
layers magnetically coupled to each other including two magnetic
poles in part of sides of the area facing a recording medium, the
magnetic poles being opposed to each other with a gap layer in
between; and a thin-film coil unit placed between the magnetic
layers with an insulating layer in between; wherein at least one of
the two magnetic layers including: a first magnetic layer portion
with a constant width for defining a width of a recording track of
a recording medium extending from a recording medium opposite
surface facing to the recording medium to an edge of the insulating
layer closer to the recording medium or its vicinity; and a second
magnetic layer portion magnetically coupled to the first magnetic
layer portion at the edge of the insulating layer or its vicinity;
wherein a step in the width direction is formed in a coupling point
of the first magnetic layer portion and the second magnetic layer
portion so as to have a width of the first magnetic layer portion
at the coupling point smaller than a width of the second magnetic
layer portion at the coupling point.
2. A thin-film magnetic head according to claim 1 wherein a step
face of the second magnetic layer portion at the coupling point is
substantially orthgonal to the extending direction of the first
magnetic layer portion.
3. A thin-film magnetic head according to claim 1 wherein a step
face of the second magnetic layer portion at the coupling point has
rounded-off edges in the width direction.
4. A thin-film magnetic head according to claim 2 wherein a step
face of the second magnetic layer portion at the coupling point has
rounded-off edges in the width direction.
5. A thin-film magnetic head according to claim 1 wherein a width
of the second magnetic layer portion is almost constant all through
the area.
6. A thin-fill magnetic head according to claim 2 wherein a width
of the second magnetic layer portion is almost constant all through
the area.
7. A thin-film magnetic head according to claim 1 wherein a width
of the second magnetic layer portion varies depending on the
area.
8. A thin-film magnetic head according to claim 2 wherein a width
of the second magnetic layer portion varies depending on the
area.
9. A thin-film magnetic head according to claim 7 wherein a width
of the second magnetic layer portion becomes wider as going further
from the coupling point.
10. A thin-film magnetic head according to claim 8 wherein a width
of the second magnetic layer portion becomes wider as going further
from the coupling point.
11. A thin-film magnetic head according to claim 1 wherein the one
of the magnetic layers further includes: a third magnetic layer
portion having larger width and area than the second magnetic layer
portion, being magnetically coupled to the second magnetic layer
portion.
12. A thin-film magnetic head according to claim 2 wherein the one
of the magnetic layer further includes: a third magnetic layer
portion having larger width and area than the second magnetic layer
portion, being magnetically coupled to the second magnetic layer
portion.
13. A thin-film magnetic head according to claim 1 wherein the
first magnetic layer portion and the second magnetic layer portion
are formed in a same body through a same procedure.
14. A thin-film magnetic head according to claim 2 wherein the
first magnetic layer portion and the second magnetic layer portion
are formed in a same body through a same procedure.
15. A thin-film magnetic head according to claim 11 wherein the
first magnetic layer portion, the second magnetic layer portion and
the third magnetic layer portion are formed in a same body through
a same procedure.
16. A thin-film magnetic head according to claim 12 wherein the
first magnetic layer portion, the second magnetic layer portion and
the third magnetic layer portion are formed in a same body through
a same procedure.
17. A thin-film magnetic head according to claim 11 wherein: the
first magnetic layer portion and the second magnetic layer portion
are formed in a same body through a same procedure and; the third
magnetic layer portion is formed as a separate body through a
different procedure from the forming procedure of the first
magnetic layer portion and the second magnetic layer portion.
18. A thin-film magnetic head according to claim 12 wherein the
first magnetic layer portion and the second magnetic layer portion
are formed in a same body through a same procedure and; the third
magnetic layer portion is formed as a separate body through a
different procedure from the forming procedure of the first
magnetic layer portion and the second magnetic layer portion.
19. A thin-film magnetic head according to claim 17 wherein the
third magnetic layer portion is placed overlapping at least a
portion of the second magnetic layer portion.
20. A thin-film magnetic head according to claim 18 wherein the
third magnetic layer portion is placed overlapping at least a
portion of the second magnetic layer portion.
21. A thin-film magnetic head according to claim 19; wherein the
third magnetic layer portion is placed overlapping a portion of the
first magnetic layer portion going over the coupling point; and an
edge face of the third magnetic layer portion closer to a recording
medium in the overlapping area is orthogonal to the extending
direction of the first magnetic layer portion.
22. A thin-film magnetic head according to claim 20; wherein the
third magnetic layer portion is placed overlapping a portion of the
first magnetic layer portion going over the coupling point; and an
edge face of the third magnetic layer portion closer to a recording
medium in the overlapping area is orthogonal to the extending
direction of the first magnetic layer portion.
23. A thin-film magnetic head according to claim 21 wherein a
position of the edge face of the third magnetic layer portion is
met with a position of the edge of the insulating layer closer to a
recording medium.
24. A thin-film magnetic head according to claim 22 wherein a
position of the edge face of the third magnetic layer portion is
met with a position of the edge of the insulating layers closer to
a recording medium.
25. A thin-film magnetic head according to claim 1 wherein at least
a portion of the second magnetic layer portion is placed on a slope
formed with the insulating layer.
26. A thin-film magnetic head according to claim 2 wherein at least
a portion of the second magnetic layer portion is placed on a slope
formed with the insulating layer.
27. A method of manufacturing a thin-film magnetic head including:
a step of forming at least two magnetic layers magnetically coupled
to each other including two magnetic poles in part of sides of the
area facing a recording medium, the magnetic poles being opposed to
each other with a gap layer in between; and a step of forming a
thin-film coil unit between the magnetic layers with an insulating
layers in between; wherein at least one of the magnetic layers is
formed so as to include a first magnetic layer portion with a
constant width for defining a width of a recording track of a
recording medium extending from a recording medium opposite surface
facing to the recording medium to an edge of the insulating layer
closer to the recording medium or its vicinity, and a second
magnetic layer portion magnetically coupled to the first magnetic
layer portion at the edge of the insulating layer or its vicinity;
and a step in the width direction is formed in a coupling point of
the first magnetic layer portion and the second magnetic layer
portion so as to have a width of the first magnetic layer portion
at the coupling point smaller than a width of the second magnetic
layer portion at the coupling point.
28. A method of manufacturing a thin-film magnetic head according
to claim 27 wherein a step face of the second magnetic layer
portion at the coupling point is substantially orthogonal to the
extending direction of the first magnetic layer portion.
29. A method of manufacturing a thin-film magnetic head according
to claim 27 wherein a step face of the second magnetic layer
portion at the coupling point has rounded-off edges in the width
direction.
30. A method of manufacturing a thin-film magnetic head according
to claim 28 wherein a step face of the second magnetic layer
portion at the coupling point has rounded-off edges in the width
direction.
31. A method of manufacturing a thin-film magnetic head according
to claim 27 wherein a width of the second magnetic layer portion is
almost constant all through the area.
32. A method of manufacturing a thin-film magnetic head according
to claim 28 wherein a width of the second magnetic layer portion is
almost constant all through the area.
33. A method of manufacturing a thin-film magnetic head according
to claim 27 wherein a width of the second magnetic layer portion
varies depending on the area.
34. A method of manufacturing a thin-film magnetic head according
to claim 28 wherein a width of the second magnetic layer portion
varies depending on the area.
35. A method of manufacturing a thin-film magnetic head according
to claim 33 wherein a width of the second magnetic layer portion
becomes wider as going further from the coupling point.
36. A method of manufacturing a thin-film magnetic head according
to claim 34 wherein a width of the second magnetic layer portion
becomes wider as going further from the coupling point.
37. A method of manufacturing a thin-film magnetic head according
to claim 27 wherein the one of the magnetic layer further includes:
a third magnetic layer portion having a larger width and area than
the second magnetic layer portion, being magnetically coupled to
the second magnetic layer portion.
38. A method of manufacturing a thin-film magnetic head according
to claim 28 wherein the one of the magnetic layer further includes:
a third magnetic layer portion having a larger width and area than
the second magnetic layer portion, being magnetically coupled to
the second magnetic layer portion.
39. A method of manufacturing a thin-film magnetic head according
to claim 27 wherein the first magnetic layer portion and the second
magnetic layer portion are formed in a same body through a same
procedure.
40. A method of manufacturing a thin-film magnetic head according
to claim 28 wherein the first magnetic layer portion and the second
magnetic layer portion are formed in a same body through a same
procedure.
41. A method of manufacturing a thin-film magnetic head according
to claim 37 wherein the first magnetic layer portion, the second
magnetic layer portion and the third magnetic layer portion are
formed in a same body through a same procedure.
42. A method of manufacturing a thin-film magnetic head according
to claim 38 wherein the first magnetic layer portion, the second
magnetic layer portion and the third magnetic layer portion are
formed in a same body through a same procedure.
43. A method of manufacturing a thin-film magnetic head according
to claim 37 wherein; the first magnetic layer portion and the
second magnetic layer portion are formed in a same body through a
same procedure; and the third magnetic layer portion is formed in a
separate body through a different procedure from the forming
procedure of the first magnetic layer portion and the second
magnetic layer portion.
44. A method of manufacturing a thin-film magnetic head according
to claim 38 wherein; the first magnetic layer portion and the
second magnetic layer portion are formed in a same body through a
same procedure; and the third magnetic layer portion is formed in a
separate body through a different procedure from the forming
procedure of the first magnetic layer portion and the second
magnetic layer portion.
45. A method of manufacturing a thin-film magnetic head according
to claim 43 wherein the third magnetic layer portion is placed
overlapping at least a portion of the second magnetic layer
portion.
46. A method of manufacturing a thin-film magnetic head according
to claim 44 wherein the third magnetic layer portion is placed
overlapping at least a portion of the second magnetic layer
portion.
47. A method of manufacturing a thin-film magnetic head according
to claim 45 wherein; the third magnetic layer portion is placed
overlapping a portion of the first magnetic layer portion going
over the coupling point; and an edge face of the third magnetic
layer portion closer to a recording medium in the overlapping area
is orthogonal to the extending direction of the first magnetic
layer portion.
48. A method of manufacturing a thin-film magnetic head according
to claim 46 wherein; the third magnetic layer portion is placed
overlapping a portion of the first magnetic layer portion going
over the coupling point; and an edge face of the third magnetic
layer portion closer to a recording medium in the overlapping area
is orthogonal to the extending direction of the first magnetic
layer portion.
49. A method of manufacturing a thin-film magnetic head according
to claim 47 wherein a position of the edge face of the third
magnetic layer portion is formed to meet with a position of the
edge of the insulating layers closer to a recording medium.
50. A method of manufacturing a thin-film magnetic head according
to claim 48 wherein a position of the edge frame face of the third
magnetic layer portion is formed to meet with a position of the
edge of the insulating layers closer to a recording medium.
51. A method of manufacturing a thin-film magnetic head according
to claim 27 wherein at least a portion of the second magnetic layer
portion is formed to be placed on a slope formed with the
insulating layer.
52. A method of manufacturing a thin-film magnetic head according
to claim 28 wherein at least a portion of the second magnetic layer
portion is formed to be placed on a slope formed with the
insulating layer.
Description
BACK GROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a thin-film magnetic head
having at least an inductive-type magnetic transducer for writing
and a method of manufacturing the same.
[0003] 2. Description of the Related Art
[0004] Improvements in the performance of a thin-film magnetic head
is sought since a surface recording density of a hard disk device
has been improved. A composite thin-film magnetic head having a
structure in which, a recording head having a inductive-type
magnetic transducer for writing and a reproducing head having a
magneto resistive (referred as MR) element for reading are stacked
is broadly used as the thin-film magnetic head. The MR element
includes an device using an effect of anisotropic magneto resistive
(referred as AMR) and another device using an effect of giant
magneto resistive (referred as GMR). The reproducing head using the
AMR element is called an AMR head or simply MR head, and the
reproducing head using the GMR element is called a GMR head. The
AMR head is used as a reproducing head whose surface recording
density is over 1 gigabit per square inch, and the GMR head is used
as the reproducing head whose surface recording density is over 3
gigabit per square inch.
[0005] The AMR head has an AMR film having the AMR effect. The GMR
head has a structure identical to the AMR head except that a GMR
film having the GMR effect is used instead of the AMR film.
However, when the same external magnetic field is applied, the GMR
film exhibits greater change in resistance than the AMR film. As a
result, the GMR head can increase the reproduction output three to
five times the AMR head.
[0006] A method in which the AMR film being used as the MR film is
exchanged with a material with better magnetic resist reactive such
as the GMR film, and a method in which a pattern width of the MR
film, especially the MR height is made appropriate are used as the
methods of improving the performance of the reproducing head. The
MR height is a length (height) from an edge of air bearing side to
an edge of the other side, and it is controlled by an etching
amount of the air bearing surface. The air bearing surface, here,
is facing a magnetic recording medium and called a track surface as
well.
[0007] On the other hand, performance improvements in a recording
head have been called while performances in a reproducing head has
improved. A factor which determines the performance of the
recording head is a throat height (TH). The throat height is a
length (height) of a pole between the air bearing surface and an
edge of an insulator which electrically isolates a thin-film coil
for generating magnetic flux. A reduction of the throat height is
needed in order to improve the recording head performance. The
throat height is controlled by an etching amount when the air
bearing surface is processed.
[0008] To improve a recording density among the performance of the
recording head, a track density of magnetic recording medium is
required to be increased. In order to achieve this, a recording
head with a narrow track structure in which a width of the top and
bottom pole on the air bearing surface, which are formed on top and
bottom sandwiching a write gap, is reduced from some microns to
sub-microns. Semiconductor process techniques are employed to
achieve the narrow track structure.
[0009] A method of manufacturing the composite thin-film magnetic
head as an example of method of manufacturing the thin-film
magnetic head of the related art will be described by referring to
FIG. 39 through FIG. 44.
[0010] As shown in FIG. 39, an insulating film 102 made of alumina
(Al.sub.2O.sub.3), for example, of about 5 to 10 .mu.m in thickness
is deposited on a substrate 101 made of aluminum oxide and titanium
carbide (Al.sub.2O.sub.3--TiC), for example. A bottom shield layer
103 for a reproducing head is formed on the insulating film 102. A
shield gap film 104 is formed on the bottom shield layer 103 by
depositing alumina 100 to 200 nm in thickness through sputtering.
An MR film 105 of tens of nanometers in thickness for making up the
MR element for reproduction is formed on the shield gap film 104,
and a desired shape is obtained by patterning through
photolithography with high precision. Next, after forming a lead
layer (not shown) on both sides of the MR film 105 as an extraction
electrode layer which is electrically connected to the MR film 105,
a shield gap film 106 is formed on the lead layer, the shield gap
film 104 and the MR film 105, and then the MR film 105 is buried in
the shield gap film 104 and 106. Further, a top shield serving as a
bottom pole (referred as bottom pole in the following description)
107 made of magnetic materials such as permalloy (NiFe) used for
both reproduction and recording head is formed on the shield gap
layer 106.
[0011] As shown in FIG. 40, an insulating film such as a write gap
layer 108 made of alumina film is formed, for example, on the
bottom pole 107, and a photoresist layer 109 in a desired pattern
is formed on the write gap layer 108 through photolithography with
high precision. Next, a thin-film magnetic coil 110 as a first
layer for an inductive recording head made of, for example, copper
(Cu) is formed on the photoresist layer 109 by, for example,
plating method. A photoresist layer 111 in a desired pattern is
formed covering the photoresist layer 109 and the coil 110 through
photolithography with high precision. Next, a heat treatment at
250.degree. C., for example, is applied to have the coil 110
flattened and have turns of the coil 110 insulated from each other.
Further, a thin-film coil 112 as a second layer made of, for
example, copper is formed by plating method. A photoresist layer
113 in a desired pattern is formed on the photoresist film 111 and
the coil 112 through photolithography with high precision, and a
heat treatment at 250.degree. C. is applied to have the coil 112
flattened and have turns of the coil 112 insulate from each
other.
[0012] As shown in FIG. 41, an opening 108a is formed by partially
etching the write gap layer 108 in a position behind the coil 110
and 112 (right-hand side in FIG. 41) in order to form a magnetic
path. Further, a top yolk-cum-top pole (referred as a top pole in
the following description) 114 made of magnetic materials for
recording head such as permalloy is selectively formed on the write
gap layer 108, the photoresist layers 109, 111 and 113. The top
pole 114 has a contact with the bottom pole 107 in the opening 108a
being magnetically coupled. Next, after the write gap layer 108 and
the bottom pole 107 are etched about 0.5 .mu.m by ion milling
etching using the top pole 114 as a mask, an overcoat layer 115
made of such as alumina is formed. The thin-film magnetic head is
completed after a track surface (air bearing surface) 120 of the
recording head and reproducing head are formed by applying machine
grinding with a slider.
[0013] FIGS. 42, 43, and 44 illustrate a completed configuration of
the thin-film magnetic head. Here, FIG. 42 shows a sectional view
of the thin-film magnetic head orthogonal to the air bearing
surface 120, and FIG. 43 is an enlarged cross-sectional view of
parallel to the air bearing surface 120 and FIG. 44 is a plan view.
FIGS. 39 to 42 show a cross section taken along the line A-A' in
FIG. 44. An illustration of the overcoat layer 115 is omitted in
FIGS. 42 to 44.
[0014] It is important to form the throat height (TH), an apex
angle (.theta.), a pole width (P2W) and a pole length P2L shown in
FIGS. 42 and 43 precisely in order to improve the performance of
the thin-film magnetic head. The apex angle .theta. is an angle
between the corner of the track surface of the photoresist layer
109, 111 and 113, and a straight line connecting the surface of the
top pole 114. The pole width P2W provides a width of a recording
track in a recording medium. The pole length P2L represents the
thickness of the pole. Further, in FIGS. 42 and 44, `TH0 position`
represents a reference position 0 of the throat height, that is, a
position of a track-side edge of the photoresist layer 109 which is
an insulating layer, electrically isolating the thin-film coils 110
and 112 from each other.
[0015] As shown in FIG. 43, a structure in which each sidewall of
the top pole 114, the write gap layer 108 and a portion of the
bottom pole 107 is vertically formed in a self-aligned manner is
called a trim structure. The trim structure prevents an increase of
the effective track width occurred through expansion of the
magnetic flux generated during writing of a narrow track. As shown
in FIG. 43, a lead layer 121 as an extraction electrode layer being
electrically connected to the MR film is provided on both sides of
the MR film 105. However, an illustration of the lead layer 121 is
omitted in FIGS. 39 to 42 and 44.
[0016] FIG. 45 illustrates a plan structure of the top pole 114. As
shown in the illustration, the top pole 114 consists mostly of a
yolk area 114a and a pole tip 114b having almost a constant width
W1 as the pole width P2W. At a coupling point of the yolk 114a and
the pole tip 114b, an outer frame of the yolk 114 has an angle
.alpha. against a surface parallel to the air bearing surface 120,
while an outer frame of the pole tip 114b has an angle .beta.
against the surface parallel to the air bearing surface 120. Here,
.alpha. is, for example, about 45 degrees and .beta. is 90 degrees.
The width of pole tip 114b defines the width of the recording
track. The pole tip 114b includes an area F in front of the TH0
position (air bearing surface 120 side) and an area R behind the
TH0 position (yolk 114a side). As shown in FIG. 4, the area F is
constant on the flat surface of the write gap layer 108, the area R
and the yolk 114a are constant on an coil area (referred as apex in
the following description) being swelled up, covered by the
photoresist film 109, 111 and 113. 16. The publication relating to
the shape of the top pole is, for example, Japanese Patent
application Laid-open Hei 8-249614 (U.S. Pat. No. 5,600,519).
[0017] Since the pole width P2W determines the track width of the
recording head, the pole width P2W needs to be formed precisely.
Especially, recently, to make high surface density recording
possible, that is to form the recording head having a narrow track
structure, micro lithography having a size of the pole width P2W of
the top pole equal to or less than 1.0 .mu.m is required.
[0018] As a method of forming the top pole, shown in, for example,
Japanese Patent Application Laid-open Hei 7-262519 (U.S. Pat. No.
5,438,747), frame plating method is used. In a case where the top
pole 114 is formed by frame plating method, a thin electrode film
made of, for example, permalloy is formed all over the apex area
by, for example, sputtering. Next, after applying a photoresist on
it, a pattern is obtained through lithography procedure to form a
frame (outer frame) for plating. The top pole 114 is formed by
plating method having the electrode film as a seed layer.
[0019] By the way, the apex area and the other areas have, for
example, more than 7 to 10 .mu.m difference in heights. A
photoresist of 3 to 4 .mu.m in thickness is applied on the apex
area. If the photoresist with equal to or more than 3 .mu.m in film
thickness on the apex is needed, a photoresist film with for
example, equal to or more than 8 to 10 .mu.m in film thickness is
formed in the lower part of the apex area since the photoresist
with liquidity gathers into a lower area.
[0020] To form a narrow track as described above, a frame pattern
with a width of about 1.0 .mu.m depending on the photoresist film
is needed to be formed. That is, micro pattern with a width of 1.0
.mu.m or less has to be formed depending on the photoresist film
with equal to or more than 8 to 10 .mu.m in thickness. However,
forming the photoresist film with such a thick film with a narrow
pattern width has been difficult.
[0021] Further, during an exposure of photolithography, a light for
the exposure reflects with the undercoat electrode film as a seed
layer and the photoresist is exposed by the reflecting light. As a
result, deformation of the photoresist pattern occurs and so that a
sharp and precise photoresist pattern can not be obtained.
Consequently, the top pole can not be formed in a desired shape
since sidewalls of the top pole take a shape being rounded.
Especially, as shown in FIG. 8, when the top pole width P2W is made
further narrower to have W1', the desired width W1' becomes harder
to obtain. It is because the width of the photoresist pattern
defining the top pole width P2W is wider than the desired value and
the shape becomes the one shown with a dotted line in FIG. 8 since
among the pole tip area 114b, in an area R being placed on the apex
area, the reflecting light being reflected from the undercoat
electrode film includes not only the reflecting light of orthogonal
direction but the reflecting lights of diagonal direction or
lateral direction from the slope of the apex area resulting in
giving an influence to photosensitivity of the photoresist layer.
Among the pole tip area 114b, a width of the area F is an extremely
important factor in defining the track width on the recording
medium. As a result, if the width of the area F becomes wider than
the value W1' described above, the narrow track width as desired
can not be obtained.
[0022] Same problems exists in the magnetic head claimed in the
Japanese Patent Application Laid-open Hei 8-249614. It is because
the width of the front area of the TH0 position cannot be
controlled precisely under the influence of an exposure of the
photoresist layer given by the reflecting light from a slope of the
apex area in diagonal and lateral direction since the pole width
from the TH0 position to the yolk area changes moderately.
[0023] As shown in FIG. 46, the connecting area R from the TH0 to
the yolk area 114a of the pole tip area 114b has about the same
width with the front area of the TH0 having a small cross sectional
view area, the magnetic flux from the yolk area 114a is saturated
in the area R so that the flux can not sufficiently reach the area
F which determines the track width. For that, an overwrite
characteristic, that is, a characteristic in a case where a data is
written on a recording medium over the already-written data,
becomes as low as 10 to 20 dB so that a sufficient overwrite
characteristic can not be obtained.
[0024] A publication relating to the present invention includes
Japanese Patent Application Laid-open Hei 1-184611 and Japanese
Patent Application Hei 10-188225. An inductive thin-film magnetic
head having a magnetic core which comprises a rectangular pole tip
with about the same width with a track width facing a magnetic
medium and a back core having a wide cross sectional area of the
pole tip, and an angle between the pole tip and the back core is
about 90 degrees is claimed in the Japanese Patent Application
Laid-open Hei 1-184611. In the Japanese Patent Application
Laid-open Hei 10-188225, a inductive thin-film magnetic head is
disclosed. In the magnetic head, a projected area which determines
the track width is formed on one side of the pole film, and the
size of each portion of the projected area is set to a specific
value.
[0025] The present invention is designed to overcome the forgoing
problems. It is an object of the invention to provide a thin-film
magnetic head in which precise control of the pole width is
performed and, at the same time, a sufficient overwrite
characteristic can be obtained even in a case where the pole width
is reduced.
SUMMARY OF THE INVENTION
[0026] A thin-film magnetic head of the invention includes at least
two magnetic layers magnetically coupled to each other including
two magnetic poles in part of sides of the area facing a recording
medium, the magnetic poles being opposed to each other with a gap
layer in between; and a thin-film coil unit placed between the
magnetic layers with an insulating layer in between. At least one
of the two magnetic layers including: a first magnetic layer
portion with a constant width for defining a width of a recording
track of a recording medium extending from a recording medium
opposite surface facing to the recording medium to an edge of the
insulating layer closer to the recording medium or its vicinity;
and a second magnetic layer portion magnetically coupled to the
first magnetic layer portion at the edge of the insulating layer or
its vicinity. A step in the width direction is formed in a coupling
point of the first magnetic layer portion and the second magnetic
layer portion so as to have a width of the first magnetic layer
portion at the coupling point smaller than a width of the second
magnetic layer portion at the coupling point.
[0027] A method of manufacturing the thin-film magnetic head of the
invention includes a step of forming at least two magnetic layers
magnetically coupled to each other including two magnetic poles in
part of sides of the area facing a recording medium, the magnetic
poles being opposed to each other with a gap layer in between; and
a step of forming a thin-film coil unit between the magnetic layers
with an insulating layers in between. At least one of the magnetic
layers is formed so as to include a first magnetic layer portion
with a constant width for defining a width of a recording track of
a recording medium extending from a recording medium opposite
surface facing to the recording medium to an edge of the insulating
layer closer to the recording medium or its vicinity, and a second
magnetic layer portion magnetically coupled to the first magnetic
layer portion at the edge of the insulating layer or its vicinity;
and a step in the width direction is formed in a coupling point of
the first magnetic layer portion and the second magnetic layer
portion so as to have a width of the first magnetic layer portion
at the coupling point smaller than a width of the second magnetic
layer portion at the coupling point.
[0028] In the thin-film magnetic head or the manufacturing method
of the same of the invention, the recording track width of the
recording medium is defined according to the specific width of the
first magnetic layer portion. The first magnetic layer portion is
magnetically coupled to the second magnetic layer portion whose
width is wider than that of the first magnetic layer portion at the
edge close to the recording medium in the insulating layer or its
vicinity, and a step in the direction of the width is formed at the
coupling point.
[0029] Further, the step face of the second magnetic layer portion
at the coupling point may be substantially orthogonal to the
extending direction of the first magnetic layer portion.
[0030] Further, the edges of the step face of the second magnetic
layer portion may be rounded off .
[0031] Further, the width of the second magnetic layer portion may
be almost constant all through the area.
[0032] Further, the width of the second magnetic layer portion may
differ depending upon the position.
[0033] Further, the width of the second magnetic layer portion may
become wider as the distance from the coupling point becomes
larger.
[0034] Further, in the thin-film magnetic head of the invention and
method of manufacturing the same, one of the magnetic may include a
third magnetic layer portion magnetically connected to the second
magnetic layer portion having larger width and area than the second
magnetic layer portion.
[0035] Further, in the thin-film magnetic head of the invention and
the method of manufacturing the same, the first magnetic layer
portion and the second magnetic layer portion may be formed in a
same procedure in a same body.
[0036] Further, in the thin-film magnetic head of the invention and
the method of manufacturing the same, the first magnetic layer
portion, the second magnetic layer portion and the third magnetic
layer portion may be formed in a same procedure in a same body.
[0037] Further, in the thin-film magnetic head in the invention and
the method of manufacturing the same, the first magnetic layer
portion and the second magnetic layer portion may be formed in a
same procedure in a same body, and the third magnetic layer portion
may be formed in a different procedure in a separate body from the
first and second magnetic layer portion.
[0038] Further, in the thin-film magnetic head of the invention and
the method of manufacturing the same, the third magnetic layer
portion may be placed overlapping at least a portion of the second
magnetic layer portion.
[0039] Further, in the thin-film magnetic head of the invention and
the method of manufacturing the same, the third magnetic layer
portion may go over the coupling point and be placed overlapping a
portion of the fir st magnetic layer portion, and an edge of the
third magnetic layer closer to the recording medium may be
orthogonal to the extending direction of the first magnetic layer
portion. In such a case, the width of the first magnetic layer
portion which determines the recording track width of the recording
medium is exactly constant all through the area from the
orthogonally crossing point to the top area even if a concave
corner of the step face in the width direction at the coupling
point is rounded off, since the coupling point of the first and the
second magnetic layer portion is receded from the edge face of the
third magnetic layer. Here, the position of the edge surface of the
third magnetic layer portion may be set in the same position of the
edge of the insulating layer closer to the recording medium. In
such a case, the width of the first magnetic layer which determines
the recording track width of the recording medium is exactly the
same all through the area so-called a throat height.
[0040] Further, in the thin-film magnetic head of the current
invention and the method of manufacturing the same, at least some
portion of the second magnetic layer portion may be set on the
slope surface formed by an insulating layer. In such a case, even
if a concave corner of the step in the width direction at the
coupling point is relatively quite rounded off due to the fact that
the second magnetic layer portion is formed on the slope mentioned
above, and so that a condition of exposure during a procedure of a
photolithography for forming the first magnetic layer portion is
made worse, variance of the substantial width of the first magnetic
layer can be avoided.
[0041] Another object, distinctive characters and effects of the
current invention will be made clear in the following
descriptions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1A and FIG. 1B are cross sectional views for describing
a procedure of the method of manufacturing of a thin-film magnetic
head of a first embodiment of the current invention.
[0043] FIG. 2A and FIG. 2B are cross sectional views for describing
the procedure following FIG. 1A and FIG. 1B.
[0044] FIG. 3A and FIG. 3B are cross sectional views for describing
the procedure following FIG. 2A and FIG. 2B.
[0045] FIG. 4A and FIG. 4B are cross sectional views for describing
the procedure following FIG. 3A and FIG. 3B.
[0046] FIG. 5A and FIG. 5B are cross sectional views for describing
the procedure following FIG. 4A and FIG. 4B.
[0047] FIG. 6A and FIG. 6B are cross sectional views for describing
the procedure following FIG. 5A and FIG. 5B.
[0048] FIG. 7A and FIG. 7B are cross sectional views for describing
the procedure following FIG. 6A and FIG. 6B.
[0049] FIG. 8 is a plan view showing a plan structure of a
completed thin-film magnetic head.
[0050] FIG. 9 is a plan view showing a plan structure of the top
pole in the thin-film magnetic head as shown in FIG. 8.
[0051] FIG. 10 is an enlarged plan view of a top pole for
describing the operation of the thin-film magnetic head shown in
FIG. 8.
[0052] FIG. 11 is an enlarged plan view of the top pole for
describing a comparative example of operation to the thin-film
magnetic head shown in FIG. 8.
[0053] FIG. 12 is an illustration showing a over write
characteristic of the thin-film magnetic head shown in FIG. 8 and
the thin-film magnetic head of a related art.
[0054] FIG. 13 is a plan view showing a modification of the top
pole of the thin-film magnetic head according to a first embodiment
of the invention.
[0055] FIG. 14 is a plan view showing another modification of the
top pole of the thin-film magnetic head according to the first
embodiment of the invention.
[0056] FIG. 15 is a plan view showing still another modification of
the top pole of the thin-film magnetic head according to the first
embodiment of the invention.
[0057] FIG. 16A and FIG. 16B are cross sectional views for
describing a procedure of the method of manufacturing of the
thin-film magnetic head according to a second embodiment of the
invention.
[0058] FIG. 17A and FIG. 17B are cross sectional views for
describing the procedure following FIG. 16A and 16B.
[0059] FIG. 18A and FIG. 18B are cross sectional views for
describing the procedure following FIG. 17A and 17B.
[0060] FIG. 19A and FIG. 19B are cross sectional views showing a
modification of the thin-film magnetic head according to the second
embodiment of the invention.
[0061] FIG. 20 is a plan view showing a plan structure of the top
pole and a top pole tip of the thin-film magnetic head according to
the second embodiment of the invention.
[0062] FIG. 21 is a plan view plan view showing an enlarged plan
structure of the top pole tip shown in FIG. 20.
[0063] FIG. 22 is a plan view showing a modification of a top pole
tip shown in FIG. 21.
[0064] FIG. 23 is a plan view showing a modification of the top
pole and the top pole tip shown in FIG. 20.
[0065] FIG. 24 is plan view showing an enlarged plan structure of
the top pole tip shown in FIG. 23.
[0066] FIG. 25 is a plan view showing another modification of the
top pole and the top pole tip shown in FIG. 20.
[0067] FIG. 26 is a plan view showing modifications of the top pole
and the top pole tip of the thin-film magnetic head of the
invention.
[0068] FIG. 27 is a plan view showing another modification of the
top pole and the top pole tip of the thin-film magnetic head of the
invention.
[0069] FIG. 28 is a plan view showing a plan structure of the top
pole and the top pole tip of the thin-film magnetic head according
to a third embodiment.
[0070] FIG. 29 is a magnified plan view of a main portion of the
top pole and the top pole tip shown in FIG. 28.
[0071] FIG. 30 is a plan view showing a modification of the top
pole and the top pole tip of the thin-film magnetic head according
to the third embodiment.
[0072] FIG. 31 is a plan view showing another modification of the
top pole and the top pole tip of the thin-film magnetic head
according to the third embodiment.
[0073] FIG. 32 is a plan view showing still another modification of
the top pole and the top pole tip of the thin-film magnetic head
according to the third embodiment.
[0074] FIG. 33A and FIG. 33B are cross sectional views for
describing a procedure of the method of manufacturing of thin-film
magnetic head according to a fourth embodiment.
[0075] FIG. 34A and FIG. 34B are cross sectional views following
FIG. 33.A and FIG. 33B
[0076] FIG. 35A and FIG. 35B are cross sectional views following
FIG. 34A and FIG. 34B.
[0077] FIG. 36A and FIG. 36B are cross sectional views for
describing a procedure of the method of manufacturing of the
thin-film magnetic head according to a fifth embodiment.
[0078] FIG. 37A and FIG. 37B are cross sectional views following
FIG. 36A and FIG. 36B.
[0079] FIG. 38A and FIG. 38B are cross sectional views following
FIG. 37A and FIG. 37B.
[0080] FIG. 39 is a cross sectional view for describing a procedure
of a method of manufacturing thin-film magnetic head of a related
art.
[0081] FIG. 40 is a cross sectional view for describing the
procedure following FIG. 39.
[0082] FIG. 41 is a cross sectional view for describing the
procedure following FIG. 40.
[0083] FIG. 42 is a cross sectional view illustrating the structure
of the conventional thin-film magnetic head.
[0084] FIG. 43 is a cross sectional view showing a cross section
parallel to an air bearing surface in the conventional thin-film
magnetic head.
[0085] FIG. 44 is a plan view showing the structure of the
conventional thin-film magnetic head.
[0086] FIG. 45 is a plan view showing a structure of a top pole in
the conventional thin-film magnetic head.
[0087] FIG. 46 is a plan view of the top pole for describing
problems occurred when applying micro lithography to the top pole
in the conventional thin-film magnetic head.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0088] Preferred embodiments of the invention will now be described
in detail with reference to the accompanying drawings.
[0089] [First Embodiment]
[0090] A method of manufacturing a composite thin-film magnetic
head as a method of manufacturing a thin-film magnetic head
according to a first embodiment of the invention will be described
with reference to FIGS. 1 to 8. The thin-film magnetic head of the
embodiment will be shown specifically in the method of
manufacturing the thin-film magnetic head of the embodiment and so
that both will together be described in the followings. Each of
FIGS. 1A to 7A shows a cross sectional view vertical to an air
bearing surface and each FIGS. 1B to 7B shows a cross sectional
view parallel to the air bearing surface of a top pole. FIG. 8
illustrates a plan structure of the composite thin-film magnetic
head.
[0091] In the manufacturing method according to the embodiment, as
shown in FIG. 1A and FIG. 1B, an insulating layer 2 made of alumina
(Al.sub.2O.sub.3), for example, of about 3 to 5 .mu.m in thickness
is deposited on a substrate 1 made of aluminum oxide and titanium
carbide (Al.sub.2O.sub.3 TiC), for example. Next, permalloy of
about 3 .mu.m in thickness is selectively formed on the insulating
layer 2 by plating with using a photoresist as a mask to form a
bottom shield layer 3 for reproducing head.
[0092] Further, alumina of 100 to 200 nm in thickness, for example,
is deposited on the bottom shield layer 3 through sputtering to
form a shield gap film 4. An MR film 5 of tens of nanometers or
less in thickness is formed on the shield gap film 4 for making up
an MR element for reproduction, and photolithography with high
precision is applied to have a desired shape. Next, after forming a
lead layer (not shown) as an extraction electrode layer which is
electrically connected to the MR film 5 on both sides of the MR
film 5, a shield gap film 6 is formed on the lead layer, the shield
gap film 4 and the MR film 5, and the MR film 5 is buried in the
shield gap film 4 and 6.
[0093] Further, as shown in FIGS. 2A and 2B, a top shield
layer-cum-bottom pole (called bottom pole in the following
description) 7 of about 3 to 4 .mu.m in thickness made of, for
example, permalloy is selectively formed on the shield gap
film.
[0094] The bottom pole 7 corresponds to at least one of `two
magnetic layers` of the invention.
[0095] Next, after forming an inorganic insulating film such as a
silicon dioxide film (SiO.sub.2), for example, of about 1 to 2
.mu.m in thickness on the bottom pole 7, an insulating film 8 for
defining an apex angle and a throat height is formed by selectively
patterned through taper etching. For the insulating layer 8, not
only a silicon dioxide but also an alumina film or a silicon
nitride (SiN) film and so on may be used. Alternatively, the film
may be formed by sputtering or CVD (Chemical Vapor Deposition)
method. Next, a write gap layer 9 made of an insulating film such
as alumina film is formed on the bottom pole 7 and the insulating
layer 8.
[0096] As shown in FIGS. 3A and 3B, a first layer of a thin-film
coil 10 of 2 to 3 .mu.m in thickness for an inductive recording
head made of, for example, copper (Cu) is formed on the write gap
layer 9 by, for example, electroplating.
[0097] As shown in FIGS. 4A and 4B, a photoresist layer 11 is
formed to a desired pattern through photolithography with high
precision on the write gap layer 9 and the coil 10. Next, a heat
treatment at 250.degree. C. is applied for flattening the coil 10
and insulating between the coils 10.
[0098] Further, a second layer of a thin-film coil 12 of 2 to 3
.mu.m in thickness made of, for example, copper is formed on the
photoresist layer 11 by, for example, electroplating. A photoresist
layer 13 in a desired pattern is formed on the photoresist layer 11
and the thin-film coil 12 by lithography with high precision, and a
heat treatment at 250.degree. C. is applied for flattening the coil
12 and having turns of the coil 12 insulated.
[0099] As shown in FIGS. 5A and 5B, an opening 9a in the back
(right side in FIG. 5A) of the coil 10 and 12 is formed by
selectively etching the write gap layer 9 to form a magnetic path.
Next, an electrode film (not shown) which is to be a seed layer in
electroplating is formed by forming NiFe-system alloy, which is a
material with high saturation flux density, of about 70 nm in
thickness by, for example, sputtering before forming a top pole. A
photoresist pattern (not shown) which is to be a frame for forming
the top pole is formed by applying photoresist on the electrode
film, patterning it using photolithography and applying frame
plating. After forming a top yolk-cum-top pole (called top pole in
the following) 17 of about 3 to 5 in thickness by electroplating
using the photoresist pattern as a mask and the electrode layer as
a seed layer, the photoresist pattern is removed. The top pole 17
takes a plan shape as shown in FIG. 9, for example, and has a
contact with the bottom pole 7 in the opening 9a and is
magnetically connected. For the top pole 17, for example, a
material with high saturation flux density such as permalloy (NiFe)
or ferrous nitride (Fen) may be used. The shape of the top pole 17
will be described later. The top pole 17 corresponds to `at least
one of two magnetic layers` in the invention.
[0100] As shown in FIG. 6A and FIG. 6B, a trim structure is formed
by etching the write gap layer 9 and the bottom pole 7 about 0.5
.mu.m by, for example, ion milling using the top pole 17 as a
mask.
[0101] As shown in FIGS. 7A and 7B, an overcoat layer 18 made of,
for example, alumina is formed covering all the surface. The
thin-film magnetic head is completed by forming a air bearing
surface (track surface) of the recording head and the reproducing
head through a slider machinning process.
[0102] FIG. 8 is a plan view of the thin-film magnetic head
manufactured through the method of manufacturing of the embodiment.
In the illustration, the overcoat layer 18 is omitted. As shown,
the throat height (TH) is a length from the edge of the pole side
of the insulating layer 8 (TH0) to an air bearing surface 20. Each
of FIG. 1A to FIG. 7A corresponds to a cross section taken along
the line A-A' in FIG. 8.
[0103] FIG. 9 illustrates a plan structure of the top pole 17. As
shown in the illustration, the top pole 17 has a yolk area 17a
composing most of the top pole having a width W3, a middle area 17b
having almost a constant width W1 and a top area 17c having almost
a constant width W2 narrower than W1. The center of each width
direction of the yolk area 17a, the middle area 17b and the top
area 17c are met with each other. The frame of the yolk area 17a
makes an angle a against a surface parallel to the air bearing
surface 20, and the side frame surface of the middle area 17b makes
an angle .beta. against a surface parallel to the air bearing
surface 20 at the coupling point of the yolk area 17a and the
middle area 17b. The width of the middle area 17b and the top area
17c each are almost constant all through the area. In the
embodiment, .alpha. is about 45 degrees, for example, and .beta. is
about 90 degrees.
[0104] The position of the coupling point of the middle area 17b
and the top area 17c of the top pole 17 meets TH0 position or its
vicinity. Here, `vicinity` means a range of .+-.0.5 .mu.m, for
example, from TH0 position. At the coupling point, the width of the
middle area 17b is W1 and the width of the top area 17c is W2
narrower than W1. That is, at TH0 position or its vicinity, there
is a step in the width direction between the middle area 17b and
the top area 17c. An end face (called step face in the following
description) 21 of the middle area 17b at the step area makes an
angle .gamma. against the side frame surface of the middle area
17b, makes an angle .delta. with the side frame direction (that is
a direction in which the top area 17c is extending) of the top area
17c. In the embodiment, both the angle .gamma. and .delta. are
about 90 degrees. That is, the step face 21 between the top area
17c and the middle area 17b is substantially vertical to the side
frame surface of the top area 17c. Here, `practically vertical`
means the angle .delta. between the main portion of the top area 17
and the main portion of the step face 21 is about 90 degrees
including a case where the corner crossing the top area 17 and the
step face 21 is a sharp edge, and at the same time, where the
corner is rounded off. It is preferable to have the angle .delta.
in a range of, for example, 75 to 120 degrees. A round shape of the
corner mentioned above can be produced even a portion corresponding
to the corner of the mask for forming a photoresist pattern is a
sharp edge. Further, even an angle of the portion facing the corner
of the mask for forming the photoresist pattern is made exactly 90
degrees, when an amount of exposure is increased during the
photolithography procedure, the angle .delta. of the top pole 17
formed through the procedure mentioned above may be widened to 110
to 120 degrees. Here, the top area 17c of the top pole 17
corresponds to `a first magnetic layer portion` of the invention,
the middle area 17b corresponds to `a second magnetic layer
portion` of the invention and the yolk area 17a corresponds to `a
third magnetic layer portion` of the invention.
[0105] As shown in FIGS. 7A and 7B, the top area 17c is placed on
the flat write gap layer 9 and the middle area 17b and the yolk
area 17a are placed on an apex area which is swelled like a hill
made of the photoresist layers 11, 13 and so on. The width W2 of
the top area 17c corresponds to the top pole width PW2 defining the
track width on the recording medium.
[0106] The following values are preferable, for example, as the
size of each part shown in FIG. 9.
[0107] Length L1 of the yolk area 17=10 to 40 .mu.m
[0108] Length L2 of the middle area 17b=3.0 to 5.0 .mu.m
[0109] Length L3 of the top area 17c (=throat height TH)=0.5 to 1.0
.mu.m
[0110] Width W1 of the middle area 17b=2.0 to 4.0 .mu.m
[0111] Width W2 of the top area 17c=0.6 to 1.2 .mu.m
[0112] Width W3 of the yolk area 17a=20 to 40 .mu.m
[0113] The thin-film magnetic head with the top pole 17 having such
a shape exhibits a high performance in overwrite characteristic.
That is, in the top pole 17 as shown in FIG. 17, the width of the
middle area 17b coupled to the top area 17c at TH0 position is W1
much larger than the width W2 of the top area 17c which defines the
track width on the recording medium, and a volume (or a magnetic
volume) of the middle area 17b is much larger than a portion R of
the related art (FIG. 46). For this reason, a magnetic flux
occurred in the yolk area 17a by the thin-film coil 10 and 12 are
not saturated in the middle area 17b and reaches the top area 17c
with sufficient amount. Accordingly, even if the top area 17c is
applied to a narrow track width such as sub-micron, a sufficient
amount of a magnetic flux for overwrite can be obtained. That is, a
sufficient overwrite characteristic can be obtained while narrow
track is being obtained.
[0114] FIG. 12 shows the overwrite characteristic of the thin-film
magnetic head of both the related art and the embodiment comparing
with each other. (A) of FIG. 12 shows the overwrite characteristic
of the conventional thin-film magnetic head having a top pole 114
shaped shown in FIG. 45, and (B) of FIG. 12 shows the overwrite
characteristic of the thin-film magnetic head of the embodiment
having the top pole 17 shaped as shown in FIG. 9. As shown in the
figure, the overwrite characteristic has been improved as the value
of the thin-film magnetic head of the related art is 26.0 dB, while
the value of the thin-film magnetic head of the embodiment is as
high as 35.5 dB.
[0115] Further, the thin-film magnetic head with the top pole 17
having a shape described above has advantages as follows even in
the manufacturing procedure. That is, as shown in FIG. 10, in the
top pole 17 of the thin-film magnetic head of the embodiment, the
angle .delta. between the step face 21 at the coupling point of the
top area 17c and the middle area 17b and the side frame surface of
the top area 17c is about 90 degrees. As a result, the reflection
from the apex area in slanting and side direction occurred during a
procedure of photolithography when selectively patterning a
photoresist by exposure using a mask is almost shut at the corner
of 90 degrees between the step face 21 at TH0 position or its
vicinity and the side frame face of the top area 17c. Therefore,
the reflection is effectively from reaching a photoresist region
for forming the top area 17c. Accordingly, widening of the pattern
width of the photoresist region for forming the top area 17c can be
suppressed. To be specific, as shown in FIG. 10, a length d1 of
part (dotted line in the figure) made wider than a desired width in
the top area 17c in the longitudinal direction of the top area 17c
can me made extremely short.
[0116] On the other hand, as shown in FIG. 11, in a case where the
angle .delta. between the step face 21 at TH0 position and the
frame side surface of the top area 17c is much larger than 90
degrees (for example, 130 degrees), the above mentioned shutting
effect of the reflection in the corner is small so that the length
d2 of part (dotted line in the figure) made wider than the desired
width W2 in the top area 17c becomes longer.
[0117] As described above, the width of the top area 17c defining
the writing track width on the recording medium can be set to a
target value W2 so as to make it possible to have the writing track
width narrow since widening of the pattern width of the photoresist
region for forming the top area 17c of the top pole 17 can be
prevented with the thin-film magnetic head of the embodiment.
[0118] As described, with the thin-film magnetic head of the
embodiment, a step in the width direction which substantially
changes to a right-angle is provided between the top area 17c and
the middle area 17b of the top pole 17 at TH0 position or its
vicinity, and the width of the middle area 17b is made sufficiently
wider than that of the top area 17c which defines the track width,
so that widening of the pattern width of the photoresist for
forming the top area 17c can be prevented to have the writing track
width micronized, and the flux occurred in the yolk area 17a is
suppressed to be saturated before reaching the top area 17c so as
to maintain a sufficient overwrite characteristic.
[0119] Further, the insulating layer 8 defining the throat height
TH is formed with inorganic insulating film in the embodiment, so
that a shift of the edge of the insulating layer 8 (or pattern
shift) and profile deterioration do not occur through a heat
treatment at about 250.degree. C. to form the coils 10 and 12. As a
result, the throat height can be controlled precisely. Further, the
MR height and the apex angle .theta. can be also controlled
precisely.
[0120] Further, in the embodiment, the insulating layer 8 for
defining the throat height is formed with an inorganic film so that
a pattern shift of the insulating layer 8 does not occur while
etching the write gap layer 9 and the bottom pole 7 to form a trim
structure which also results in obtaining a precise control of the
throat height.
[0121] Further, in the embodiment, a thick insulating layer 8,
besides the thin write gap layer 9, is formed between the bottom
pole (top shield) 7 and the thin-film coils 10 and 12 so that a
large dielectric withstand voltage between the bottom pole (top
shield) 7 and the thin-film coils 10 and 12 can be obtained, and at
the same time, a flux leakage from the thin-film coils 10 and 12
can be decreased.
[0122] In the embodiment, NiFe or ferrous nitride (FeN), for
example, are used as the top pole 17, however, materials with high
saturation flux density such as amorphous of Fe--Co--Zr, for
example, can be used or more than two kinds of these materials
stacked together can be used as well. Further, a magnetic material
made up of NiFe and the materials with high saturation flux density
mentioned above being stacked together can be used as the bottom
pole 7.
[0123] Further, the top pole 17 is not limited to the shape shown
in FIG. 9. Shapes shown in FIG. 13 to 15 may also be
applicable.
[0124] FIG. 13 is a plan view of the top pole 17 of which both
outer corner of the step face 21 of the middle area 17b at TH0
position is slightly rounded off. The structure except for the part
rounded off is identical to FIG. 9. In such a case, the width of
the step face 21 after being rounded off is made same with W1.
[0125] FIG. 14 is a plan view of the top pole 17 of which an angle
.delta. between the step face 21 and the side frame surface of the
top area 17c at TH0 position is made larger than 90 degrees. The
angle .delta. is made, for example, 90 to 150 degrees, however, a
range of 90 to 120 degrees is more preferable.
[0126] FIG. 15 is a plan view of the top pole 17 of which the angle
.gamma. between the side frame surface of the middle area 17b and a
surface parallel to the air bearing surface 20 is made smaller than
90 degrees. However, the angle .gamma. is more preferable to be set
in a range from 70 to 80 degrees.
[0127] In FIGS. 13 to 15, the coupling point of the top area 17c
and the middle area 17b is not necessarily met exactly with TH0
position but may be shifted within a range of about, for example,
.+-.0.5 .mu.m from TH0 position.
[0128] With the thin-film magnetic head having a top pole 17 shown
in FIG. 13 to 15, same effect as the thin-film magnetic head having
a top pole 17 shown in FIG. 9 can be obtained.
[0129] [Second Embodiment]
[0130] Next, a second embodiment of the invention will be
described.
[0131] A method of manufacturing of a composite thin-film magnetic
head as a method of manufacturing the thin-film magnetic head of
the second embodiment will be described with reference to FIGS. 16A
and 16B to FIGS. 19A and 19B. The thin-film magnetic head of the
embodiment will be shown specifically in the method of
manufacturing of the thin-film magnetic head of the embodiment and
so that both will together be described in the followings. Each of
FIG. 16A to FIG. 19A illustrates a cross sectional view orthogonal
to the air bearing surface and each of FIG. 16B to FIG. 19B
illustrates a cross sectional view parallel to the air bearing
surface of the top pole area. In the figures, like numerals are
adopted to the same elements as those in the above mentioned
embodiment.
[0132] In the method of manufacturing the thin-film magnetic head
according to the embodiment, the procedure of forming from the
insulating layer 2 to the bottom pole 7 shown in FIG. 16A and FIG.
16B will be omitted since it is identical to that of the first
embodiment shown in FIG. 3A and FIG. 3B.
[0133] In the embodiment, after the bottom pole 7 as shown in FIGS.
16A and 16B is formed, the write gap layer 9 as shown in FIG. 17A
and FIG. 17B is formed and an insulating pattern 25 for defining
the throat height TH is formed on the write gap layer 9. Next, an
opening 9a for forming a magnetic path is formed by selectively
etching the write gap layer 9 in a position which is back
(right-hand side in FIG. 17A) of the region where a thin-film coil
29 is formed in the later procedure. Next, a top pole tip 27a which
is to be a portion of the top pole is formed selectively in a area
form the insulating pattern 25 to the area of the
track-opposite-surface side (air bearing surface side) by, for
example, electroplating and, at the same time, a magnetic path
forming pattern 27b is formed in the opening 9a. For example,
materials with high saturation flux density such as alloy including
permalloy (NiFe) or alloy including ferrous nitride (FeN) are used
as the top pole 27a and the magnetic path forming pattern 27b.
[0134] The top pole tip 27a and the magnetic path forming pattern
27b are formed as follows, for example. First, an electrode film
(not shown) as a seed layer for electroplating is formed by about
70 nm in thickness through, for example, sputtering. The seed layer
is made of alloy including NiFe which is a material with high
saturation flux density. Next, a photoresist pattern (not shown) is
formed by applying photoresist on the electrode film, patterning it
by photolithography and applying frame plating. Next, the top pole
tip 27a and the magnetic path forming pattern 27b of about 3 to 5
.mu.m in thickness are formed by electroplating using photoresist
pattern as a mask, and the electrode film as a seed layer, then,
the photoresist pattern is removed. The top pole tip 27a takes a
shape shown in FIGS. 20 and 21, for example. The shape of the top
pole tip 27a will be described in the followings.
[0135] Next, a trim structure is formed by etching the write gap
layer 9 and the bottom pole about 0.3 to 0.5 .mu.m by, for example,
ion milling using the top pole 17 as a mask. The trim structure is
for suppressing the widening of the substancial track width when
writing.
[0136] Next, after forming an insulating film 28 of 0.5 to 1.5
.mu.m in thickness, made of such as alumina film all over, a
thin-film coil 29 of 2 to 3 .mu.m in thickness made of, for
example, copper (Cu) for an inductive recording head is formed by,
for example, electroplating. After forming an insulating film 30 of
about 3 to 4 .mu.m in thickness made of such as alumina film all
over, the top surfaces of the top pole tip 27a and the magnetic
path forming pattern 27b are exposed by polishing so that the whole
surface is flattened through, for example, CMP (chemical machine
polishing).
[0137] Next, as shown in FIGS. 18A and 18B, the top yolk-cum-top
pole (called top pole in the followings) 27c of about 3 to 5 .mu.m
in thickness is formed by electroplating through the same procedure
as that of forming the top pole tip 27a and the magnetic path
forming pattern 27b. The top pole 27c takes a shape shown in FIG.
20, for example, being in a contact and magnetically connected to
both the magnetic path forming pattern 27b and the top pole tip
27a. For example, materials with high saturation flux density such
as permalloy (NiFe) or ferrous nitride (FeN) are used as the top
pole 17. Here, the top pole 27c corresponds to a `third magnetic
layer portion` of the invention.
[0138] Next, an overcoat layer 31 made of, for example, alumina is
formed covering the whole surface. Then, the thin-film magnetic
head is completed by forming the air bearing surface (track
surface) of the recording head and the reproducing head by
performing a slider machining process.
[0139] Only one layer of the thin-film coil 29 is formed here,
however, as shown in FIGS. 19A and 19B, a second layer of thin-film
coil 35 may be formed on the insulating layer 30 covering the
thin-film coil 29 and, after covering it by the photoresist layer
36, a top pole 37 may be selectively formed thereon.
[0140] FIG. 20 illustrates a plan structure of the top pole 27c and
the top pole tip 27a and FIG. 21 illustrates a plan structure of
the top pole tip 27a. As shown in FIG. 20, the top pole 27c
comprises a yolk area 27c(1) which occupies most portion of the top
pole 27c having a width W3 and a connecting area 27c(2) which
overlaps the top pole tip 27a in some portion. The shape of the
yolk area 27c(1) is identical to the yolk area 17a of the top pole
17 in the first embodiment. The width of the connecting area 27c(2)
is made wider than the width of the middle area 17b of top pole 17
in the first embodiment. The centers of each width direction of the
yolk area 27c(1) and the connecting area 27c(2) are formed to be
met mutually.
[0141] As shown in FIG. 21, the top pole tip 27a has a top area
27a(1) defining the writing track width on the recording medium and
a middle area 27a(2) connected to the connecting area 27c(2) of the
top pole 27c. The middle area 27a(2) has a width W1 which is same
as that of the middle area 17b of the top pole 17 in the first
embodiment, and has a length L4. The top area 27a(1) has a width W2
which is same as that of the top pole 17c in the first embodiment.
The coupling point of the top area 27a(1) and the middle area
27a(2) is almost met with TH0 position and, at the same time, met
with the edge face in front (air bearing side) of the connecting
area 27c(2) of the top pole 27c. At the coupling point (that is,
TH0 position), the width of the middle area 27a(2) is W1, and that
of the top pole 27a(1) is W2 which is narrower than W1. That is, at
TH0 position or its vicinity, there is a step in the width
direction between the middle area 27a(2) and the top area 27a(1).
The step face 21 of the middle area 27a(2) at the step makes an
angle .gamma.1 with the side face of the middle area 27a(2) and
makes an angle .delta. with the side face of the top area 27a(1).
In the embodiment, both angles .gamma.1 and .delta. are almost 90
degrees. That is, both the middle area 27a(2) and the top area
27a(1) takes a shape of rectangle and the step face 21 is
substantially orthogonal to the side face of the top area 27a(1).
Here, the top area 27a(1) corresponds to a `first magnetic layer
portion` of the invention, and the middle area 27a(2) corresponds
to a `second magnetic layer portion` of the invention.
[0142] As evident in FIGS. 18 to 20, the top area 27a(1) is
extending on the flat write gap layer 9, and the middle area 27a(2)
is located on the insulating pattern 25.
[0143] The values as follows, for example, are preferable as the
size of each part shown in FIG. 20.
[0144] Width W1 of the middle area 27a(2)=2.0 to 5.0 .mu.m
[0145] Length L4 of the middle area 27a(2)=1.0 to 5.0 .mu.m
[0146] Width W2 of the top area 27a(1)=0.4 to 1.2 .mu.m
[0147] Width W3 of the yolk area 17a=30 to 40 .mu.m
[0148] Length of the connecting area 27c(2)=3.0 to 5.0 .mu.m
[0149] The thin-film magnetic head with the top pole having a shape
described above exhibits a high performance in overwrite
characteristic for the same reasons as the first embodiment.
Further, the magnetic head with the top pole 27c and the top pole
tip 27a having shapes as described above has same advantages as the
first embodiment in the manufacturing process.
[0150] That is, according to the thin-film magnetic head of the
embodiment, widening of the pattern width of the photoresist for
forming the top area 27a(1) of the top pole tip 27a can be
prevented. As a result, the writing track width assume smaller and,
at the same time, a sufficient overwrite character can be
maintained by suppressing the magnetic flux occurred in the yolk
area 27c(1) to be saturated before reaching the top area 27a(1) of
the top pole tip 27a.
[0151] Further, in the embodiment, forming the photoresist pattern
by photolithography can be performed with high precision since the
top pole 27c can be formed on a surface which has been flattened by
CMP.
[0152] Further, in the embodiment, a thick insulating film 28 made
of such as alumina is formed between the write gap layer 9 and the
thin-film coil 10 so that an dielectric withstand voltage between
the thin-film coil 10 and the bottom electrode 7 can be increased
and, at the same time, leakage of the magnetic flux from the
thin-film coil 10 can be decreased.
[0153] The top pole 27c and the top pole tip 27a are not limited to
the shapes shown in FIGS. 20 and 21 but may take the shapes shown
in FIGS. 22 to 24, for example.
[0154] FIG. 22 is a plan view of the top pole tip 27a of which both
outer corners of the step face 21 of the middle area 27a(2) are
rounded off. The structure except for the area which is rounded off
is identical to that of FIG. 21. The rounded angle .eta. of the
step face 21 is preferred to be 30 to 60 degrees, for example.
[0155] FIG. 23 illustrates a plan structure in which the connecting
area 27c(2) of the top pole 27c and the middle area 27a(2) of the
top pole tip 27a have tapered shape, and FIG. 24 illustrates a plan
structure of the top pole tip 27a. In these figures, the taper
angle .gamma. of the connecting area 27c(2) of the top pole 27c is
set in a range of, for example, 45 to 60 degrees, against the edge
face 22 of the connecting area 27c(2), the taper angle .gamma.1 of
the middle area 27a(2) of the top pole tip 27a is preferred to be
set in a range of, for example, 60 to 80 degrees, against the step
face 21.
[0156] With the thin-film magnetic head having the top pole 27c and
the top pole tip 27a shown in FIGS. 22 to 24, the same effect as
the thin-film magnetic head having the top pole 27c and the top
pole tip 27a shown in FIG. 20 can be obtained.
[0157] The position of the edge face 22 in front (air bearing side)
of the connecting area 27c(2) of the top pole 27c does not
necessarily be met exactly with the step face 21 of the top pole
tip 27a which is met with TH0 position. For example, as shown in
FIG. 25, the position of the edge face 22 of the connecting area
27c(2) may be shifted to the back (opposite of the air bearing
surface) of the position of the step face 21.
[0158] Further, the connecting area 27c(2) of the top pole 27c in
the second embodiment (FIG. 20) is not essential. For example, as
shown in FIG. 26, the top pole 27c may be composed only of the yolk
area 27c(1), and some portion of the yolk area 27c(1) may be
overlapped on the middle area 27a(2) of the top pole tip 27a. In
such a case, the position of the edge face 22 in front (air bearing
side) of the yolk area 27c(1) does not necessarily be met exactly
with the position of the step face 21 of the top pole tip 27a which
is met with TH0 position. For example, as shown in FIG. 27, the
position of the edge face 22 in front of the yolk area 27c(1) may
be shifted to the back (opposite of the air bearing surface) of the
position of the step face 21 of the top pole tip 27a.
[0159] [Third Embodiment]
[0160] A third embodiment of the invention will be described in the
followings.
[0161] FIG. 28 illustrates a plan structure of the top pole 27c and
the top pole tip 27a in the third embodiment of the invention and
FIG. 29 shows the main part of FIG. 28 being enlarged. In these
figures, like numerals are adopted to the elements which are
identical to those shown in FIG. 20 in the second embodiment, and
description will be omitted when not necessary.
[0162] As shown in FIGS. 28 and 29, in the embodiment, the
connecting area 27c(2) of the top pole 27c is extending to overlap
a portion of the top area 27a(1) in such a manner that the edge
face 22 thereof goes over the position of the step face 21 of the
top pole tip 27a. The edge face 22 of the connecting area 27c(2) in
the overlapping area is orthogonal to the extending direction of
the top area 27a(1), that is, to the direction of the side face 23
of the top area 27a(1). Further, in the embodiment, TH0 position is
met with the position of the edge face 22 of the connecting area
27c(2) but not the position of the step face 21 of the top pole tip
27a. Other structures and the manufacturing method are identical to
those of the second embodiment. For example, the cross sectional
structure taken along the face orthogonal to the air bearing
surface 20 going through the top area 27a(1) is identical with the
one shown in FIGS. 18 or 19.
[0163] As described with reference to FIG. 18, the photolithography
procedure for forming the top pole tip 27a and the photolithography
procedure for forming the top pole 27c are performed separately. As
a result, even if the corner of the photoresist is rounded due to a
poor condition of exposure during the photolithography procedure
for forming the top pole tip 27a so that the crossing part 24
formed by the step face 21 of the top pole tip 27a and the side
face 23 of the top area 27a(1) does not assume a corner with a
sharp right angle, that is, the crossing part 24 is rounded off, as
shown in FIG. 29, the side face 23 of the top area 27a(1) and the
connecting area 27c(2) of the top pole 27c invariably makes a sharp
right angle. That is, the width of the top area 27a(1) for defining
the track width of the recording medium is made to be W1 precisely
through the whole region from TH0 position to the air bearing
surface (i.e. whole region of throat height TH). Accordingly, in a
case where the width W1 of the top area 27a(1) is made less than 1
.mu.m or, further, less than 0.5 .mu.m in accordance with narrowing
of the track width, the width W1 of the top area 27a(1) is not
widened at TH0 position or in the vicinity of TH0 position.
Especially, even in a case where the value of the throat height TH
is reduced from the value of about 1 .mu.m to the value of 0.5 to
0.2 .mu.m to obtain the thin-film magnetic head with higher
performance, a precise design value width W1 can be guaranteed all
through the region of the throat height TH. As a result, the
recording track width on the recording medium can be controlled
precisely, and a sidewrite phenomenon in which a data to be written
on a specific track is written on a neighboring track can be
effectively prevented.
[0164] Further, in the embodiment, the connecting area 27c(2) which
spreads in the width direction of the top area 27a(1) is being
placed immediately behind TH0 position of the top area 27a(1) and,
at the same time, the middle area 27a(2) is being placed
immediately behind the step face 21, so that a sufficient magnetic
volume is maintained. As a result, saturation of the magnetic flux
occurred in the yolk area 27c(1) before reaching the top area
27a(1) of the top pole tip 27a can be effectively prevented, and a
sufficient overwrite characteristic can be maintained.
[0165] In a case where the edge face 22 of the connecting area
27c(2) of the top pole 27c is placed in a position over the step
face 21 of the top pole tip 27a like the embodiment, the shape of
the top pole tip 27a and the top pole 27c are not limited to the
ones shown in FIG. 28. As shown in FIG. 30, for example, the
connecting area 27c(2) of the top pole 27c and the middle area
27a(2) of the top pole tip 27a may take the shapes with taper,
respectively. The taper angle of the connecting area 27c(2) of the
top pole 27c and the taper angle of the middle area 27a(2) of the
top pole tip 27a are preferred to be made same as in the case of
FIG. 23.
[0166] Further, as shown in FIG. 31, the top pole 27c can be
composed only of the yolk area 27c(1) without the connecting area
27c(2) and the yolk area 27c(1) may be overlapped so that the end
frame face 22 of the yolk area 27c(1) is placed on the top area
27a(1) going over the step face 21 of the top pole tip 27a.
[0167] Further, as shown in FIG. 32, the step face 21 of the top
pole tip 27a and the side face 23 of the top area 27a(1) may make
an angle larger than 90 degrees. However, it is preferable to make
the angle 90 degrees between the step face 21 and the side face
23.
[0168] In the second and third embodiment, a case in which the top
pole area of the thin-film magnetic head is formed being divided
into two parts such as the top pole 27c and the top pole tip 27a
and, at the same time, the whole thin-film magnetic head has a
cross sectional structure as shown in FIG. 19, however, the
invention is not limited to the embodiment. The structures in a
fourth and fifth embodiments described in the followings may also
be applicable.
[0169] [Fourth Embodiment]
[0170] Next, a method of manufacturing a composite thin-film
magnetic head as a method of manufacturing the thin-film magnetic
head of the fourth embodiment of the invention will be described
with reference to FIG. 33A and FIG. 33B to FIG. 35A and FIG. 35B.
The thin-film magnetic head of the invention is specified in the
method of manufacturing of the thin-film magnetic head of the
embodiment so that both together be described in the followings.
Each of FIG. 33A to FIG. 35A shows a cross sectional view
orthogonal to the air bearing surface and each of FIG. 33B to FIG.
35B shows a cross sectional view parallel to the air bearing
surface of the pole area. In these figures, like numerals are
adopted to the elements which are identical to those of the
forgoing embodiments respectively.
[0171] In the method of manufacturing the thin-film magnetic head,
a description of the procedure until forming the bottom pole 7
shown in FIG. 33A and FIG. 33B is omitted since it is identical to
the procedure shown in FIG. 1A and FIG. 1B to part of FIG. 3A and
FIG. 3B of the first embodiment.
[0172] In the embodiment, after forming the bottom electrode 7, a
bottom pole tip 41a and a bottom connecting area 41b of about 2.0
to 2.5 .mu.m in thickness are formed on the bottom electrode 7 as
shown in FIG. 33A and FIG. 33B. Here, the bottom pole tip 41a is
formed to be extended from the area near the air bearing surface
(i.e. the vicinity of an MR (GMR) height 0 position) to the throat
height 0 position. The bottom pole tip 41a and the bottom
connecting area 41b may be formed as a plated film such as NiFe, or
as a sputtered film such as FeN, FeZrNP, or CoFeN.
[0173] Next, an insulating film 42 of 0.3 to 0.6 .mu.m in thickness
made of an insulating material such as alumina is formed all over
the surface by, for example, sputtering method or CVD method.
[0174] Next, a first thin-film coil 43 of 1.5 to 2.5 .mu.m in
thickness made of such as copper (Cu) for an inductive recording
head is formed in a concave region formed between the bottom pole
tip 41a and the bottom connecting area 41b by, for example,
electroplating. Here, at the same time, a coil connecting area 43C
for connecting the thin-film coil 43 and a second layer of
thin-film coil which will be described in the following is formed
in a back region (right-hand side region in the figure) of the
bottom connecting area 41b.
[0175] Next, an insulating film 44 of 3.0 to 4.0 .mu.m in thickness
made of an insulating material such as alumina is formed all over
the surface by sputtering method, then, the surface thereof is
flatten by, for example, CMP method to have the top surface of the
bottom pole tip 41a and the bottom connecting area 41b exposed.
[0176] Next, as shown in FIG. 34A and FIG. 34B, a write gap layer 9
of 0.2 to 0.3 .mu.m in thickness made of, for example, an alumina
insulating material is formed by sputtering method. The write gap
layer 9 may be formed with materials such as aluminum nitride
(AlN), silicon oxide, and silicon nitride other than alumina. An
opening 9a for connecting the top pole and the bottom pole is
formed by patterning the write gap layer 9 through photolithography
and, at the same time, an opening 9b to exposure the coil
connecting area 43C is formed by patterning the write gap layer 9
and the insulating layer 44.
[0177] Further, a top pole tip 45a is formed on the write gap layer
9, and a top connecting area 45b for magnetically coupling the top
pole and the bottom pole is formed so as to overlap with the bottom
connecting area 41b and to have a contact therewith. On the other
hand, the top pole tip 45a is formed extending longer than the
bottom pole tip 41a in a backward direction from the air bearing
surface. The top pole tip 45a is formed, like the third embodiment
(shown in such as FIG. 28), having the middle area 27a(2) for
maintaining a magnetic volume, the top area 27a(1) for defining the
track width and the step face 21 at the coupling point. The plan
shape of top pole tip 45a is same as that shown in FIGS. 28, 30,
31, or 32. Further, the top pole tip 45a is to be placed so that
the step face 21 is located in a position slightly backward of the
edge face position (that is, TH0 position) which is in the back
side of the bottom pole tip 41a.
[0178] Further, the write gap layer 9 and the bottom pole tip 41a
are etched in a self-aligned manner using the top pole tip 45a as a
mask. That is, after selectively removing the write gap layer 9
through RIE by chlorine system gas (Cl.sub.2, CF.sub.4, BCl.sub.2,
SF.sub.6, and so on), using the top pole tip 45a as a mask, a trim
structure is formed by further etching the exposed bottom pole tip
41a about 0.3 to 0.6 .mu.m by, for example, ion milling with
Ar.
[0179] Further, an insulating layer 46 of 0.3 to 0.6 in thickness
made of such as alumina is formed all over the surface by, for
example, sputtering method or CVD method. Next, a second layer of
thin-film coil 47 of 1.5 to 2.5 .mu.m in thickness made of copper
(Cu) for an inductive recording head is formed by, for example,
electroplating on the insulating film 46 in the concave area formed
between the top pole tip 45a and the top connecting area 45b. Here,
at the same time, the coil connecting area 47C which has a contact
with the coil connecting area 43C through the opening area 9b is
formed.
[0180] Further, an insulating layer 48 of about 3 to 4 .mu.m in
thickness made of such as alumina is formed all over the surface
by, for example, sputtering method or CVD method. The insulating
layer 48 and the insulating film 46 may be formed with insulating
materials, other than alumina, such as silicon dioxide (SiO.sub.2)
and silicon nitride (SiN).
[0181] Next, polishing is performed by, for example, CMP method so
that the top surface of the top pole tip 45a and the top connecting
area 45b is exposed. As a result , the surface of the top pole tip
45a and the top connecting area 45b is flattened so as to have a
same surface level as that of the insulating layer 48 and the
insulating firm 46.
[0182] Next, as shown in FIG. 35A and FIG. 35B, a top pole 49 of
about 3 to 4 .mu.m in thickness made of, for example, the same
material with the top pole tip 45a is selectively formed by, for
example, electroplating or sputtering method. Here, some portion of
the top pole 49 overlaps with the top pole tip 45a and a position
of the edge face 22 which is in the front side (air bearing surface
side) of the top pole 49 is placed to meet the position of the
back-side edge (that is, TH0 position) of the bottom pole tip 41a.
Further, the backside edge position of the top pole 49 is placed
being in touch with the top connecting area 45b. As a result, the
top pole 49 is magnetically connected to the top pole tip 45a and,
at the same time, magnetically connected to the bottom pole 7
through the top connecting area 45b and the bottom connecting area
41b.
[0183] Further, an overcoat layer 50 of about 30 .mu.m in thickness
made of such as alumina is formed all over the surface by, for
example, sputtering. Then, the thin-film magnetic head is completed
by forming the air bearing surface (ABS) of the recording head and
the reproducing head through applying slider machining process.
[0184] In the embodiment, the top pole 49 is formed with the
position of the front-side edge face 22 being at TH0 position and,
at the same time, being in forward position of the step face 21 of
the top pole tip 45a. As a result, such an effect as that of the
third embodiment as shown in FIG. 29 can be obtained.
[0185] [Fifth Embodiment]
[0186] A method of manufacturing a composite thin-film magnetic
head as the method of manufacturing the thin-film magnetic head
according to a fifth embodiment of the invention will be described
with reference to FIG. 36A to FIG. 38B. The thin-film magnetic head
of the invention is specified in the method of manufacturing the
thin-film magnetic head of the embodiment so that both together be
described in the followings. Each of FIG. 36A to FIG. 38A shows a
cross sectional view orthogonal to the air bearing surface and each
of FIG. 36B to FIG. 38B shows a cross sectional view parallel to
the air bearing surface of the pole area. In these figures, like
numerals are adopted to the elements which are identical to those
of the forgoing embodiments respectively.
[0187] In the method of manufacturing the thin-film magnetic head,
a description of the procedure until forming the bottom pole 7 as
shown in FIG. 36A and FIG. 36B is omitted since it is identical to
the procedure shown in FIG. 1A and FIG. 1B to part of FIG. 3A and
FIG. 3B of the first embodiment.
[0188] In the embodiment, after forming the bottom electrode 7, a
bottom pole tip 61a and a bottom connecting area 61b are formed on
the bottom electrode 7 as shown in FIG. 36A and FIG. 36B. Here, the
bottom pole tip 41a is formed to be extended from the area near the
air bearing surface (i.e. the vicinity of an MR (GMR) height 0
position) to the throat height 0 position.
[0189] Next, an insulating film 62 of 3.0 to 4.0 .mu.m in thickness
made of an insulating material such as alumina is formed all over
the surface by sputtering method, then, flatten all of the surface
by, for example, CMP method to have the top surface of the bottom
pole tip 61a and the bottom connecting area 61b exposed.
[0190] Next, as shown in FIG. 37A and FIG. 37B, the write gap layer
9 of 0.2 to 0.3 .mu.m in thickness made of, for example, an alumina
insulating material is formed by sputtering method. The opening 9a
for connecting the top pole and the bottom pole is formed by
patterning the write gap layer 9 through photolithography.
[0191] Next, a top pole tip 63a is formed on the write gap layer 9,
and a top connecting area 63b for magnetically coupling the top
pole and the bottom pole is formed so as to overlap with the bottom
connecting area 61b and to have a contact therewith. On the other
hand, the top pole tip 63a is formed extending longer than the
bottom pole tip 61a in a backward direction from the air bearing
surface. The top pole tip 63a is formed, like the third embodiment
(shown in such as FIG. 28), having the middle area 27a(2) for
maintaining a magnetic volume, the top area 27a(1) for defining the
track width and the step face 21 at the coupling point. The plan
shape of top pole tip 63a is same as that shown in FIGS. 28, 30,
31, or 32. Further, the top pole tip 63a is to be placed so that
the step face 21 is located in a position slightly backward of the
edge face position (that is, TH0 position) which is in the back
side of the bottom pole tip 61a.
[0192] Further, a trim structure is formed by etching the write gap
layer 9 and the bottom pole tip 61a in a self-aligned manner using
the top pole tip 63a as a mask.
[0193] Next, a first layer of thin-film coil 64 of 1.5 to 2.5 .mu.m
in thickness made of copper (Cu) for an inductive recording head is
formed by, for example, electroplating on the write gap layer 9 in
the concave area formed between the top pole tip 63a and the top
connecting area 63b. Here, at the same time, the coil connecting
area 64C for coupling the thin-film coil 64 and a second layer of
thin-film coil which will be described in the following is formed
in a back region (right-hand side region in the figure) of the top
connecting area 63b.
[0194] Next, as shown in FIG. 38A and FIG. 38B, an insulating film
65 of 3.0 to 4.0 .mu.m in thickness made of an insulating material
such as alumina is formed all over the surface by sputtering
method, then, the surface thereof is flattened by, for example, CMP
method to have the top surface of the bottom pole tip 63a and the
bottom connecting area 63b exposed.
[0195] Next, an opening 65a reaching the coil connecting area 64C
is formed by selectively etching the insulating layer 65.
[0196] Next, a second layer of a thin-film coil 66 of 1.5 to 2.5
.mu.m in thickness made of such as copper (Cu) for an inductive
recording head is formed on the insulating layer 65 by, for
example, electroplating. Here, at the same time, a coil connecting
area 66C having a contact with the connecting area 64C through the
opening 65a is formed.
[0197] Next, a photoresist layer 67 covering the thin-film coil 66
and the coil connecting area 64C is formed by photolithography with
high precision, then, a heat treatment at 250.degree. C. is applied
to have the surface of the photoresist layer 67 flattened and turn
of the thin-film coil 66 insulated to each other.
[0198] Next, a top pole 68 of about 3 to 4 .mu.m in thickness made
of, for example, the same material with the top pole tip 63a is
selectively formed by, for example, electroplating or sputtering
method. Here, a portion of the top pole 68 overlaps with the top
pole tip 63a and a position of the edge face 22 which is in the
front side (air bearing surface side) of the top pole 68 is placed
to meet the position of the back-side edge (that is, TH0 position)
of the bottom pole tip 61a. Further, the back-side edge position of
the top pole 68 is placed being in touch with the top connecting
area 63b. As a result, the top pole 68 is magnetically coupled to
the top pole tip 63a and, at the same time, magnetically coupled to
the bottom pole 7 through the top connecting area 63b and the
bottom connecting area 61b.
[0199] Further, an overcoat layer 69 of about 30 .mu.m in thickness
made of such as alumina is formed all over the surface by, for
example, sputtering. Then, the thin-film magnetic head is completed
by forming the air bearing surface (ABS) of the recording head and
the reproducing head through applying a slider machining
process.
[0200] With the embodiment, same operation and effect as the third
and fourth embodiments can be obtained. That is, a sidewrite
phenomenon can be effectively prevented by precisely controlling
the recording track width on the recording medium and, at the same
time, a sufficient overwrite characteristic can be maintained.
[0201] Further, in the embodiment, the top pole tip 63a can be
formed on a flattened area so that a photoresist pattern can be
formed by photolithography with high precision. As a result, a
width of the top area 27a(1) of the top pole tip 63a can be
micronized as precise as 0.5 to 0.25 .mu.m.
[0202] The invention has been described in the forgoing
embodiments, however, it is not limited to the embodiments but may
be practiced still other way with modifications. For example, the
method of manufacturing the composite thin-film magnetic head is
described in the forgoing embodiments and the modification
examples, however, the invention may be applied to a thin-film
magnetic head for recording only or a thin-film magnetic head for
recording and reproducing, having an induction magnetic transducer
for writing. The invention may be applied to a thin-film magnetic
head in which an element for writing and an element for reading are
stacked in a reverse order.
[0203] As described above, according to the thin-film magnetic head
and the method of manufacturing the same of the invention, at least
one of the two magnetic layers include a first magnetic layer
portion with a constant width for defining a width of a recording
track of a recording medium extending from a recording medium
opposite surface facing to the recording medium to an edge of the
insulating layer closer to the recording medium or its vicinity;
and a second magnetic layer portion magnetically coupled to the
first magnetic layer portion at the edge of the insulating layer or
its vicinity. A step in the width direction is formed in a coupling
point of the first magnetic layer portion and the second magnetic
layer portion so as to have a width of the first magnetic layer
portion at the coupling point smaller than a width of the second
magnetic layer portion at the coup ling point. Accordingly, an
influence of an unnecessary reflection from the undercoat layer in
the photolithography procedure of forming the first magnetic layer
portion can be suppressed so as to have the width of the first
magnetic layer formed precisely and, at the same time, a magnetic
flux occurred through thin-film coils is prevented from being
saturated in the second magnetic layer portion before reaching the
first magnetic layer portion. As a result, the width of the first
magnetic layer portion can be micronized to, for example,
sub-microns and, at the same time, an effect of maintaining an
sufficient overwrite characteristic can be obtained.
[0204] According to other thin-film magnetic head and the method of
manufacturing the same, a step face of the second magnetic layer
portion at the coupling point is substantially orthgonal to the
extending direction of the first magnetic layer portion.
Accordingly, an influence of an unnecessary reflection from the
undercoat layer in the photolithography procedure for forming the
first magnetic layer portion is effectively suppressed, and the
width of the first magnetic layer portion is more precisely
formed.
[0205] Further, according to still another thin-film magnetic head
or the method of manufacturing the same, the third magnetic layer
portion is placed overlapping a portion of the first magnetic layer
portion going over the coupling point; and an edge face of the
third magnetic layer portion closer to a recording medium in the
overlapping area is orthogonal to the extending direction of the
first magnetic layer portion. As a result, the width of the first
magnetic layer portion which determines the recording track width
of the recording medium becomes exactly constant without being
influenced all through the area from the orthogonally crossing
point to the top area, even if a concave corner of the step of the
width direction at the coupling point is rounded off. As a result,
the width of the recording track of the recording medium can be
precisely controlled.
[0206] Further, according to the thin-film magnetic head or the
method of manufacturing the same of the invention, a position of
the edge face of the third magnetic layer portion is met with a
position of the edge of the insulating layer closer to a recording
medium, so that the width of the first magnetic layer becomes
exactly constant all through the whole range of so-called throat
height, and the width of the recording track of the recording
medium can be more precisely controlled.
[0207] Further, according to the thin-film magnetic head or the
method of manufacturing the same of the invention, even if a bad
influence of the condition of exposure in the photolithography
procedure for forming the first magnetic layer occurs due to the
fact that the second magnetic layer is formed on the slope, having
a comparatively large rounded part in the concave corner of the
step in the width direction at the coupling point, varying of the
substantial width of the first magnetic layer portion can be
avoided. That is, stabilizing the width of the pole for recording
formed on the slope, which was difficult hitherto, can be
performed.
[0208] Obviously many modifications and variations of the present
invention are possible in the light of the above teachings. It is
therefore to be understood that within the scope of the appended
claims the invention may be practiced otherwise than as
specifically described.
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