U.S. patent application number 09/480624 was filed with the patent office on 2002-04-25 for thin-film magnetic head and method of manufacturing same.
Invention is credited to Iijima, Atsushi, Sasaki, Yoshitaka.
Application Number | 20020048115 09/480624 |
Document ID | / |
Family ID | 16998288 |
Filed Date | 2002-04-25 |
United States Patent
Application |
20020048115 |
Kind Code |
A1 |
Sasaki, Yoshitaka ; et
al. |
April 25, 2002 |
THIN-FILM MAGNETIC HEAD AND METHOD OF MANUFACTURING SAME
Abstract
A thin-film magnetic head and a method of manufacturing the same
of the invention achieve a reduction in yoke length and prevent
generation of voids in an insulating layer for isolating turns of a
thin-film coil from each other. In the thin-film magnetic head of
the invention, a recording head has: a bottom pole layer; a top
pole layer; a recording gap layer located between pole portions of
the pole layers; and a thin-film coil located between the pole
layers. The bottom pole layer has a first portion located to face
the thin-film coil; and a second portion forming the pole portion
and connected to a surface of the first portion that faces the
thin-film coil. The coil is placed on a side of the second portion.
An insulating layer for insulating turns of the thin-film coil from
each other includes a first insulating film and a second insulating
film. The first insulating film is made of a photoresist, for
example, and touches an insulating film. The first insulating film
is placed to fill the space between the turns of the coil. The
second insulating film is made of an inorganic insulating material
and placed to cover the first insulating film.
Inventors: |
Sasaki, Yoshitaka; (Tokyo,
JP) ; Iijima, Atsushi; (Tokyo, JP) |
Correspondence
Address: |
Oliff & Berridge PLC
P O Box 19928
Alexandria
VA
22320
US
|
Family ID: |
16998288 |
Appl. No.: |
09/480624 |
Filed: |
January 10, 2000 |
Current U.S.
Class: |
360/125.43 ;
360/123.5; 360/125.62; G9B/5.086; G9B/5.094 |
Current CPC
Class: |
G11B 5/313 20130101;
G11B 5/3163 20130101 |
Class at
Publication: |
360/126 |
International
Class: |
G11B 005/147 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 24, 1999 |
JP |
11-236269 |
Claims
What is claimed is:
1. A thin-film magnetic head comprising: a first magnetic layer and
a second magnetic layer magnetically coupled to each other and
including magnetic pole portions opposed to each other and placed
in regions of the magnetic layers on a side of a medium facing
surface of the head that faces toward a recording medium, each of
the magnetic layers including at least one layer; a gap layer
provided between the pole portions of the first and second magnetic
layers; and a thin-film coil at least part of which is placed
between the first and second magnetic layers, the at least part of
the coil being insulated from the first and second magnetic layers;
wherein: at least one of the magnetic layers includes: a first
portion located in a position that faces the at least part of the
coil; and a second portion forming one of the pole portions and
connected to a surface of the first portion that faces the coil;
and the at least part of the coil is placed on a side of the second
portion; the head further comprising an insulating layer for
insulating turns of the at least part of the coil from each other;
wherein the insulating layer includes: a first insulating film made
of an insulating material that exhibits fluidity during formation
and touching a layer to be a base of the at least part of the coil,
the first insulating film being placed to fill at least part of
spaces between the turns of the at least part of the coil and
between the second portion and the at least part of the coil; and a
second insulating film made of an inorganic insulating material and
placed to cover the first insulating film.
2. The thin-film magnetic head according to claim 1, wherein the
first insulating film is made of an organic insulating
material.
3. The thin-film magnetic head according to claim 1, wherein the
first insulating film is a spin-on-glass film.
4. The thin-film magnetic head according to claim 1, wherein a
surface of the second insulating film opposite to the first
insulating film is flattened.
5. The thin-film magnetic head according to claim 1, wherein the
first insulating film is located to cover the at least part of the
thin-film coil.
6. The thin-film magnetic head according to claim 1, wherein the
first insulating film is located such that the part of the spaces
is filled with the first insulating film.
7. A method of manufacturing a thin-film magnetic head comprising:
a first magnetic layer and a second magnetic layer magnetically
coupled to each other and including magnetic pole portions opposed
to each other and placed in regions of the magnetic layers on a
side of a medium facing surface of the head that faces toward a
recording medium, each of the magnetic layers including at least
one layer; a gap layer provided between the pole portions of the
first and second magnetic layers; and a thin-film coil at least
part of which is placed between the first and second magnetic
layers, the at least part of the coil being insulated from the
first and second magnetic layers; the method including the steps
of: forming the first magnetic layer; forming the gap layer on the
first magnetic layer; forming the second magnetic layer on the gap
layer; forming the coil such that the at least part of the coil is
placed between the first and second magnetic layers, the at least
part of the coil being insulated from the first and second magnetic
layers; wherein: in at least one of the step of forming the first
magnetic layer and the step of forming the second magnetic layer,
at least one of the magnetic layers is formed to include: a first
portion located in a position that faces the at least part of the
coil; and a second portion forming one of the pole portions and
connected to a surface of the first portion that faces the coil;
and in the step of forming the coil, the at least part of the coil
is placed on a side of the second portion; the method further
including the step of forming an insulating layer for insulating
turns of the at least part of the coil from each other; wherein the
step of forming the insulating layer includes the steps of: forming
a first insulating film made of an insulating material that
exhibits fluidity during formation such that the first insulating
film touches a layer to be a base of the at least part of the coil
and is placed to fill at least part of the spaces between the turns
of the at least part of the coil and between the second portion and
the at least part of the coil; and the step of forming a second
insulating film made of an inorganic insulating material to cover
the first insulating film.
8. The method according to claim 7, wherein the first insulating
film is made of an organic insulating material.
9. The method according to claim 7, wherein the first insulating
film is a spin-on-glass film.
10. The method according to claim 7, further including the step of
flattening a surface of the second insulating film opposite to the
first insulating film.
11. The method according to claim 7, wherein the first insulating
film is formed to cover the at least part of the thin-film coil in
the step of forming the first insulating film.
12. The method according to claim 7, wherein the first insulating
film is formed such that the part of the spaces is filled with the
first insulating film in the step of forming the first insulating
film.
13. The method according to claim 7, wherein the step of forming
the first insulating layer includes the steps of: forming a film
made of the insulating material that exhibits fluidity during
formation to cover the at least part of the coil; and removing the
film placed on top of the at least part of the coil.
Description
BACKGROUND OF THE INVENTION
[0001] 1. 1. Field of the Invention
[0002] The present invention relates to a thin-film magnetic head
having at least an induction-type magnetic transducer and a method
of manufacturing the thin-film magnetic head.
[0003] 2. Description of the Related Art
[0004] Performance improvements in thin-film magnetic heads have
been sought with an increase in surface recording density of a hard
disk drive. A composite thin-film magnetic head has been widely
used, which is made of a layered structure including a recording
head having an induction-type magnetic transducer for writing and a
reproducing head having a magnetoresistive (MR) element for
reading.
[0005] It is required to increase the track density on a magnetic
recording medium in order to increase the recording density as one
of the performance characteristics of a recording head. To achieve
this, it is required to implement a recording head of a narrow
track structure wherein the track width, that is, the width of a
bottom pole and a top pole sandwiching the recording gap layer on
the air bearing surface (medium facing surface) is reduced to the
micron or submicron order. Semiconductor process techniques are
employed to achieve the narrow track structure.
[0006] Reference is now made to FIG. 16A to FIG. 19A and FIG. 16B
to FIG. 19B to describe an example of a method of manufacturing a
composite thin-film magnetic head as a related-art method of
manufacturing a thin-film magnetic head. FIG. 16A to FIG. 19A are
cross sections each orthogonal to the air bearing surface. FIG. 16B
to FIG. 19B are cross sections of a pole portion each parallel to
the air bearing surface.
[0007] In the manufacturing method, as shown in FIG. 16A and FIG.
16B, an insulating layer 102 made of alumina (Al.sub.2O.sub.3), for
example, having a thickness of about 5 to 10 .mu.m is deposited on
a substrate 101 made of aluminum oxide and titanium carbide
(Al.sub.2O.sub.3-TiC), for example. On the insulating layer 102 a
bottom shield layer 103 made of a magnetic material is formed for
making a reproducing head.
[0008] Next, on the bottom shield layer 103, alumina, for example,
is deposited to a thickness of 100 to 200 nm through sputtering to
form a bottom shield gap film 104 as an insulating layer. On the
bottom shield gap film 104 an MR element 105 for reproduction
having a thickness of tens of nanometers is formed. Next, on the
bottom shield gap film 104, a pair of electrode layers 106 are
formed. The electrode layers 106 are electrically connected to the
MR element 105.
[0009] Next, a top shield gap film 107 is formed as an insulating
layer on the bottom shield gap film 104 and the MR element 105. The
MR element 105 is embedded in the shield gap films 104 and 107.
[0010] Next, on the top shield gap film 107, a top shield
layer-cum-bottom pole layer (called a bottom pole layer in the
following description) 108 having a thickness of about 3 .mu.m is
formed. The bottom pole layer 108 is made of a magnetic material
and used for both a reproducing head and a recording head.
[0011] Next, as shown in FIG. 17A and FIG. 17B, on the bottom pole
layer 108, a recording gap layer 109 made of an insulating film
such as an alumina film whose thickness is 0.2 .mu.m is formed.
Next, a portion of the recording gap layer 109 is etched to form a
contact hole 119a to make a magnetic path. On the recording gap
layer 109 in the pole portion, a top pole tip 110 made of a
magnetic material and having a thickness of 0.5 to 1.0 .mu.m is
formed for the recording head. At the same time, a magnetic layer
119 made of a magnetic material is formed for making the magnetic
path in the contact hole 109a for making the magnetic path.
[0012] Next, as shown in FIG. 18A and FIG. 18B, the recording gap
layer 109 and the bottom pole layer 108 are etched through
ion-milling, using the top pole tip 110 as a mask. As shown in FIG.
18B, the structure is called a trim structure wherein the sidewalls
of the top pole (the top pole tip 110), the recording gap layer
109, and part of the bottom pole layer 108 are formed vertically in
a self-aligned manner.
[0013] Next, an insulating layer 111 made of an alumina film, for
example, and having a thickness of about 3 .mu.m is formed on the
entire surface. The insulating layer 111 is then polished to the
surfaces of the top pole tip 110 and the magnetic layer 119 and
flattened.
[0014] Next, on the flattened insulating layer 111, a thin-film
coil 112 of a first layer is made of copper (Cu), for example, for
the induction-type recording head. Next, a photoresist layer 113 is
formed into a specific pattern on the insulating layer 111 and the
coil 112. Heat treatment is then performed to flatten the surface
of the photoresist layer 113. On the photoresist layer 113, a
thin-film coil 114 of a second layer is formed. Next, a photoresist
layer 115 is formed into a specific pattern on the photoresist
layer 113 and the coil 114. Heat treatment is performed to flatten
the surface of the photoresist layer 115.
[0015] Next, as shown in FIG. 19A and FIG. 19B, a top pole layer
116 is formed for the recording head on the top pole tip 110, the
photoresist layers 113 and 115, and the magnetic layer 119. The top
pole layer 116 is made of a magnetic material such as Permalloy.
Next, an overcoat layer 117 of alumina, for example, is formed to
cover the top pole layer 116. Finally, machine processing of the
slider including the above-described layers is performed to form an
air bearing surface 118 of the recording head and the reproducing
head. The thin-film magnetic head is thus completed.
[0016] FIG. 20 is a top view of the thin-film magnetic head shown
in FIG. 19A and FIG. 19B. The overcoat layer 117 and other
insulating layers and insulating films are omitted in FIG. 20.
[0017] In FIG. 19A and FIG. 19B, `TH` indicates the throat height
and `MR-H` indicates the MR height. The throat height is the length
(height) of the pole portion, that is, the portion of the two
magnetic layers facing each other with the recording gap layer in
between, between the air-bearing-surface-side end and the other
end. The MR height is the length (height) of the MR element between
the air-bearing-surface-side end and the other end. In FIG. 19A and
FIG. 19B, `P2W` indicates the pole width, that is, the track width
of the recording head (hereinafter called the recording track
width). In addition to the throat height, the MR height and so on,
the apex angle as indicated with .theta. in FIG. 19A and FIG. 19B
is one of the factors that determine the performance of a thin-film
magnetic head. The apex is a hill-like raised portion of the coils
112 and 114 covered with the photoresist layers 113 and 115. The
apex angle is the angle formed between the top surface of the
insulating layer 111 and the straight line drawn through the edges
of the pole-side lateral walls of the apex.
[0018] In order to improve the performance of the thin-film
magnetic head, it is important to precisely form throat height TH,
MR height MR-H, apex angle .theta., and recording track width P2W
as shown in FIG. 19A or FIG. 19B.
[0019] To achieve high density recording, a reduction in track
width and an increase in reproducing output are required for a
recording head of a composite thin-film magnetic head as described
above. A reduction in track width is required for a recording head,
too. An improvement in high-frequency characteristic is required,
too, for a recording head to cope with an increase in frequency of
data to be written. To improve the high-frequency characteristic of
a recording head, it is known that it is preferred to reduce the
yoke length, that is, the length of the magnetic path made of the
magnetic layers between the air-bearing-surface-side end and the
other end.
[0020] One of the methods to reduce the yoke length may be to
reduce the coil pitch. For example, the yoke length is required to
be 20 to 10 .mu.m or less in order to implement a thin-film
magnetic head that achieves recording density of 30 to 50 gigabits
per square inch or more and performs desirable recording in a
high-frequency band of 300 to 500 MHz or more. To obtain such a
yoke length, the coil pitch is required to be 2.0 to 1.0 .mu.m or
less, that is, 0.6 .mu.m, for example. If the coil pitch is 0.6
.mu.m, the line width of winding is 0.3 .mu.m and the space between
windings is 0.3 .mu.m, for example.
[0021] In prior art a photoresist layer is used as an insulating
layer for isolating windings of a coil from each other. The
outermost end of the photoresist layer defines the throat
height.
[0022] However, a rounded portion is formed near the outermost end
of the photoresist layer since the photoresist has fluidity during
its formation. As a result, the distance between the outermost end
of the coil and the zero throat height position (the position of an
end of the pole portion opposite to the air bearing surface) is
increased in prior art, which is a major factor that prevents a
reduction in yoke length. The reason will now be described in
detail. Since the yoke length of a two-layer coil can be shorter
than that of a single-layer coil, a two-layer coil is adopted to
many of recording heads for high frequency application. However, in
a related-art thin-film magnetic head, a photoresist film having a
thickness of about 2 .mu.m is formed to cover the first layer of
the coil for insulating the turns of the coil from each other after
the first layer is formed. A rounded portion is formed as described
above around the outermost end of the photoresist layer covering
the first layer of the coil. A second layer of the coil is then
formed on the photoresist layer. The second layer is required to be
formed on a flat portion since it is impossible to etch the seed
layer of the coil in the rounded portion near the outermost end of
the photoresist layer, and the coil is thereby shorted.
[0023] Therefore, if the total coil thickness is 2 to 3 .mu.m, the
thickness of the photoresist layer insulating the turns of the coil
from each other is 2 .mu.m, and the apex angle is 45 to 55 degrees,
for example, the yoke length is required to be 6 to 8 .mu.m which
is twice as long as the distance between the outermost end of the
coil and the neighborhood of the zero throat height position, that
is, 3 to 4 .mu.m (the distance between the innermost end of the
coil and the portion where the top and bottom pole layers are
connected to each other is required to be 3 to 4 .mu.m, too), in
addition to the length of the portion corresponding to the coil.
This length of the portion other than the portion corresponding to
the coil is one of the factors that prevent a reduction in yoke
length.
[0024] Assuming that a two-layer eleven-turn coil whose line width
is 1.5 .mu.m and the space between turns is 0.5 .mu.m is
fabricated, for example, the portion of the yoke length
corresponding to the coil 112 of the first layer is 11.5 .mu.m, if
the first layer is made up of six turns and the second layer is
made up of 5 turns, as shown in FIG. 19A and FIG. 19B. In addition
to this length, the total of 6 to 8 .mu.m, that is, the distance
between each of the outermost and innermost ends of the coil 112 of
the first layer and each of ends of the photoresist layer 113 for
insulating the coil 112, is required for the yoke length. The yoke
length is therefore 17.5 to 19.5 .mu.m. In the present patent
application, the yoke length is the length of a portion of the pole
layer except the pole portion and the contact portions as indicated
with L.sub.0 in FIG. 19A and FIG. 19B. As thus described, it is
impossible in the prior art to reduce the yoke length, which
prevents improvements in high frequency characteristic.
[0025] If a photoresist layer is used as an insulating layer for
insulating turns of the coil from each other, problems further
arising are that the photoresist tends to be deformed with time and
that the photoresist layer is expanded due to heat generated around
the coil when the thin-film magnetic head is used and the pole
portion protrudes toward the recording medium.
[0026] In place of a resin insulation material (organic insulation
material) such as a photoresist, the insulating layer for isolating
the turns of the coil from each other may be made of an inorganic
insulating material harder than a resin insulation material such as
alumina or silicon dioxide.
[0027] However, if an insulating layer made of an inorganic
insulation material is formed in a space between the turns of the
coil having an aspect ratio of nearly 1 and a height of 0.5 to 1.0
.mu.m or more and a width of 2.0 .mu.m or less, for example, a
problem is that the space between the turns is not completely
filled with the inorganic insulation material and gaps called voids
or keyholes are likely to be formed in the insulating layer. If
such voids are formed in the insulating layer, a washing liquid or
water goes into the voids during a number of cleaning steps using
liquids performed after the formation of the coil until the
magnetic head is completed. Such a liquid or water erodes the coil
and the reliability of the head is reduced.
[0028] As disclosed in Published Unexamined Japanese Patent
Application Hei 7-311912 (1995), after the coil is formed, a resist
is applied in which the space between the turns of the coil is half
buried, and then the remaining space between the turns is covered
with an inorganic oxide. An insulating layer for isolating the
turns of the coil from each other may be thus formed. In this case,
deformation of the insulating layer with time and generation of
voids in the insulating layer are prevented.
[0029] However, in this case, too, a rounded portion is formed near
the outermost end of the resist layer formed first. It is therefore
difficult to reduce the yoke length.
OBJECT AND SUMMARY OF THE INVENTION
[0030] It is an object of the invention to provide a thin-film
magnetic head and a method of manufacturing the same for reducing
the yoke length and preventing generation of voids in the
insulating layer for isolating the turns of the thin-film coil from
each other.
[0031] A thin-film magnetic head of the invention comprises: a
first magnetic layer and a second magnetic layer magnetically
coupled to each other and including magnetic pole portions opposed
to each other and placed in regions of the magnetic layers on a
side of a medium facing surface of the head that faces toward a
recording medium, each of the magnetic layers including at least
one layer; a gap layer provided between the pole portions of the
first and second magnetic layers; and a thin-film coil at least
part of which is placed between the first and second magnetic
layers, the at least part of the coil being insulated from the
first and second magnetic layers. At least one of the magnetic
layers includes: a first portion located in a position that faces
the at least part of the coil; and a second portion forming one of
the pole portions and connected to a surface of the first portion
that faces the coil. The at least part of the coil is placed on a
side of the second portion. The head further comprises an
insulating layer for insulating turns of the at least part of the
coil from each other. The insulating layer includes: a first
insulating film made of an insulating material that exhibits
fluidity during formation and touching a layer to be a base of the
at least part of the coil, the first insulating film being placed
to fill at least part of the spaces between the turns of the at
least part of the coil and between the second portion and the at
least part of the coil; and a second insulating film made of an
inorganic insulating material and placed to cover the first
insulating film.
[0032] A method of the invention is provided for manufacturing a
thin-film magnetic head comprising: a first magnetic layer and a
second magnetic layer magnetically coupled to each other and
including magnetic pole portions opposed to each other and placed
in regions of the magnetic layers on a side of a medium facing
surface of the head that faces toward a recording medium, each of
the magnetic layers including at least one layer; a gap layer
provided between the pole portions of the first and second magnetic
layers; and a thin-film coil at least part of which is placed
between the first and second magnetic layers, the at least part of
the coil being insulated from the first and second magnetic
layers.
[0033] The method of manufacturing the thin-film magnetic head
includes the steps of: forming the first magnetic layer; forming
the gap layer on the first magnetic layer; forming the second
magnetic layer on the gap layer; forming the coil such that the at
least part of the coil is placed between the first and second
magnetic layers, the at least part of the coil being insulated from
the first and second magnetic layers. In at least one of the step
of forming the first magnetic layer and the step of forming the
second magnetic layer, at least one of the magnetic layers is
formed to include: a first portion located in a position that faces
the at least part of the coil; and a second portion forming one of
the pole portions and connected to a surface of the first portion
that faces the coil. In the step of forming the coil, the at least
part of the coil is placed on a side of the second portion. The
method further includes the step of forming an insulating layer for
insulating turns of the at least part of the coil from each other.
The step of forming the insulating layer includes the steps of:
forming a first insulating film made of an insulating material that
exhibits fluidity during formation such that the first insulating
film touches a layer to be a base of the at least part of the coil
and is placed to fill at least part of the spaces between the turns
of the at least part of the coil and between the second portion and
the at least part of the coil; and the step of forming a second
insulating film made of an inorganic insulating material to cover
the first insulating film.
[0034] According to the thin-film magnetic head or the
manufacturing method of the invention, the at least part of the
thin-film coil is placed on a side of the second portion, so that
an end of the at least part of the coil is placed near an end of
the second portion. The yoke length is thereby reduced. In the
invention the insulating layer for insulating turns of the at least
part of the coil from each other includes: the first insulating
film made of an insulating material that exhibits fluidity during
formation and touching a layer to be a base of the at least part of
the coil, the first insulating film being placed to fill at least
part of the spaces between the turns of the at least part of the
coil and between the second portion and the at least part of the
coil; and the second insulating film made of an inorganic
insulating material and placed to cover the first insulating film.
As a result, generation of voids in the insulating layer for
insulating turns of the coil from each other is prevented.
[0035] According to the head or the method of the invention, the
first insulating film may be made of an organic insulating material
or may be a spin-on-glass film.
[0036] According to the head or the method, a surface of the second
insulating film opposite to the first insulating film may be
flattened.
[0037] According to the head or the method, the first insulating
film may be formed to cover at least part of the thin-film coil or
may be formed such that the part of the spaces is filled with the
first insulating film.
[0038] According to the method of the invention, the step of
forming the first insulating layer may include the steps of:
forming a film made of the insulating material that exhibits
fluidity during formation to cover the at least part of the coil;
and removing the film placed on top of the at least part of the
coil through etch back.
[0039] Other and further objects, features and advantages of the
invention will appear more fully from the following
description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] FIG. 1A and FIG. 1B are cross sections for illustrating a
step in a method of manufacturing a thin-film magnetic head of a
first embodiment of the invention.
[0041] FIG. 2A and FIG. 2B are cross sections for illustrating a
step that follows FIG. 1A and FIG. 1B.
[0042] FIG. 3A and FIG. 3B are cross sections for illustrating a
step that follows FIG. 2A and FIG. 2B.
[0043] FIG. 4A and FIG. 4B are cross sections for illustrating a
step that follows FIG. 3A and FIG. 3B.
[0044] FIG. 5A and FIG. 5B are cross sections for illustrating a
step that follows FIG. 4A and FIG. 4B.
[0045] FIG. 6 is an explanatory view illustrating the
correspondence of a top view and a cross-sectional view of the main
part of the thin-film magnetic head of the first embodiment.
[0046] FIG. 7A and FIG. 7B are cross sections for illustrating a
step in a method of manufacturing a thin-film magnetic head of a
second embodiment of the invention.
[0047] FIG. 8A and FIG. 8B are cross sections for illustrating a
step that follows FIG. 7A and FIG. 7B.
[0048] FIG. 9A and FIG. 9B are cross sections for illustrating a
step that follows FIG. 8A and FIG. 8B.
[0049] FIG. 10A and FIG. 10B are cross sections for illustrating a
step that follows FIG. 9A and FIG. 9B.
[0050] FIG. 11A and FIG. 11B are cross sections for illustrating a
step in a method of manufacturing a thin-film magnetic head of a
third embodiment of the invention.
[0051] FIG. 12A and FIG. 12B are cross sections for illustrating a
step that follows FIG. 11A and FIG. 11B.
[0052] FIG. 13A and FIG. 13B are cross sections for illustrating a
step that follows FIG. 12A and FIG. 12B.
[0053] FIG. 14A and FIG. 14B are cross sections for illustrating a
step that follows FIG. 13A and FIG. 13B.
[0054] FIG. 15 is an explanatory view illustrating the
correspondence of a top view and a cross-sectional view of the main
part of the thin-film magnetic head of the third embodiment.
[0055] FIG. 16A and FIG. 16B are cross sections for illustrating a
step in a method of manufacturing a thin-film magnetic head of
related art.
[0056] FIG. 17A and FIG. 17B are cross sections for illustrating a
step that follows FIG. 16A and FIG. 16B.
[0057] FIG. 18A and FIG. 18B are cross sections for illustrating a
step that follows FIG. 17A and FIG. 17B.
[0058] FIG. 19A and FIG. 19B are cross sections for illustrating a
step that follows FIG. 18A and FIG. 18B.
[0059] FIG. 20 is a top view of the related-art thin-film magnetic
head.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0060] Preferred embodiments of the invention will now be described
in detail with reference to the accompanying drawings.
[0061] [First Embodiment]
[0062] Reference is now made to FIG. 1A to FIG. 5A, FIG. 1B to FIG.
5B, and FIG. 6 to describe a thin-film magnetic head and a method
of manufacturing the thin-film magnetic head of a first embodiment
of the invention. FIG. 1A to FIG. 5A are cross sections each
orthogonal to an air bearing surface. FIG. 1B to FIG. 5B are cross
sections each parallel to the air bearing surface of a pole
portion.
[0063] In the method of manufacturing the thin-film magnetic head
of the embodiment, as shown in FIG. 1A and FIG. 1B, an insulating
layer 2 made of alumina (Al.sub.2O.sub.3), for example, whose
thickness is about 5 .mu.m, is deposited on a substrate 1 made of
aluminum oxide and titanium carbide (Al.sub.2O.sub.3-TiC), for
example. On the insulating layer 2 a bottom shield layer 3 made of
a magnetic material such as Permalloy and having a thickness of
about 3 .mu.m is formed for making a reproducing head. The bottom
shield layer 3 is formed through plating selectively on the
insulating layer 2 with a photoresist film as a mask, for example.
Next, although not shown, an insulating layer of alumina, for
example, having a thickness of 4 to 5 .mu.m, for example, is formed
over the entire surface. This insulating layer is polished through
chemical mechanical polishing (CMP), for example, so that the
bottom shield layer 3 is exposed and the surface is flattened.
[0064] Next, on the bottom shield layer 3, a bottom shield gap film
4 as an insulating layer having a thickness of about 20 to 40 nm,
for example, is formed. On the bottom shield gap film 4, an MR
element 5 for reproduction having a thickness of tens of nanometers
is formed. The MR element 5 may be fabricated through selectively
etching an MR film formed through sputtering. The MR element 5 may
be an element made of a magnetosensitive film exhibiting a
magnetoresistivity, such as an AMR element, a GMR element, or a
tunnel magnetoresistive (TMR) element. Next, on the bottom shield
gap film 4, a pair of electrode layers 6 having a thickness of tens
of nanometers are formed. The electrode layers 6 are electrically
connected to the MR element 5. Next, a top shield gap film 7 having
a thickness of about 20 to 40 nm, for example, is formed as an
insulating film on the bottom shield gap film 4 and the MR element
5. The MR element 5 is embedded in the shield gap films 4 and 7. An
insulation material used for the shield gap films 4 and 7 may be
alumina, aluminum nitride, diamond-like carbon (DLC), and so on.
The shield gap films 4 and 7 may be fabricated through sputtering
or chemical vapor deposition (CVD). If the shield gap films 4 and 7
made of alumina are fabricated through CVD, materials used are
trimethyl aluminum (Al(CH.sub.3).sub.3) and H.sub.2O, for example.
Through the use of CVD, it is possible to make the thin and precise
shield gap films 4 and 7 with few pinholes.
[0065] Next, on the top shield gap film 7, a first portion 8a of a
top shield layer-cum-bottom pole layer (called a bottom pole layer
in the following description) 8 having a thickness of about 1.0 to
2.0 .mu.m is selectively formed. The bottom pole layer 8 is made of
a magnetic material and used for both a reproducing head and a
recording head. The bottom pole layer 8 is made up of this first
portion 8a, and a second portion 8b and a third portion 8c
described later. The first portion 8a of the bottom pole layer is
placed in a position facing at least part of a thin-film coil
described later.
[0066] Next, as shown in FIG. 2A and 2B, the second portion 8b and
the third portion 8c of the bottom pole layer 8, each having a
thickness of about 1.5 to 2.0 .mu.m, are formed on the first
portion 8a. The second portion 8b makes up a pole portion of the
bottom pole layer 8 and is connected to a surface of the first
portion 8a on which a thin-film coil is to be formed (that is, the
upper side of FIG. 2A and FIG. 2B). The third portion 8c is
provided for connecting the first portion 8a to a top pole layer
described later. The throat height is defined by the position of an
end of a portion of the second portion 8b that faces the top pole
layer, the end being opposite to an air bearing surface 30. This
position is the zero throat height position.
[0067] The second portion 8b and the third portion 8c of the bottom
pole layer 8 may be made of NiFe (80 weight % Ni and 20 weight %
Fe), or NiFe (45 weight % Ni and 55 weight % Fe) as a high
saturation flux density material through plating or may be made of
a material such as FeN or FeZrN as a high saturation flux density
material through sputtering. Alternatively, a material such as CoFe
or a Co-base amorphous material as a high saturation flux density
material may be used.
[0068] Next, an insulating film 9 of alumina, for example, is
formed over the entire surface. The thickness of the insulating
film 9 is about 0.3 to 0.6 .mu.m.
[0069] Next, a photoresist is applied to the top of the insulating
film 9 on a side of the second portion 8b of the bottom pole layer
8, and patterned through a photolithography process. A frame (not
shown) to be used for making a thin-film coil through the frame
plating method is thus formed. A thin-film coil 10 made of copper
(Cu), for example, is formed on the insulating film 9 by frame
plating through the use of the frame. For example, the thickness of
the coil 10 is 0.8 to 1.5 .mu.m, the line width of the coil is 0.5
to 1.0 .mu.m, and the space between neighboring lines is 0.5 to 1.0
.mu.m. Next, the frame is removed. Numeral 10a in the drawings
indicates a portion for connecting the thin-film coil 10 to a
conductive layer (lead) described later.
[0070] Next, a first insulating film 11a made of an insulating
material that exhibits fluidity during formation is made through
photolithography, for example. The first insulating film 11a is
selectively formed to touch the insulating film 9 as a base layer
of the coil 10 and to fill the space between the turns of the coil
10 and the space between the third portion 8c of the bottom pole
layer 8 and the coil 10, and to cover the coil 10. The first
insulating film 11a may be made of an organic insulating material
such as a photoresist or may be a spin-on-glass (SOG) film made of
applied glass.
[0071] Next, heat treatment is performed on the first insulating
film 11a to fill the above-mentioned spaces with the first
insulating film 11a completely, and to flatten the top surface of
the first insulating film 11a. For example, ultraviolet (UV) cure
or annealing is performed at a temperature in a range of 100 to
200.degree. C.
[0072] Next, as shown in FIG. 3A and FIG. 3B, a second insulating
film 11b is formed through sputtering, for example, to cover the
first insulating film 11a. The second insulating film 11b is made
of an inorganic insulating material and harder than the first
insulating film 11a and has a thickness of about 3 to 4 .mu.m, for
example. The inorganic insulating material for making the second
insulating film 11b may be alumina or silicon dioxide. Next, the
insulating film 11b is polished through CMP, for example, until the
second portion 8b and the third portion 8c of the bottom pole layer
8 are exposed, and the surface is flattened.
[0073] In such a manner an insulating layer 11 for insulating the
space between the turns of the coil 10 is made of the first
insulating film 11a and the second insulating film 11b.
[0074] Next, as shown in FIG. 4A and FIG. 4B, a recording gap layer
12 made of an insulating material whose thickness is about 0.15 to
0.20 .mu.m, for example, is formed on the second portion 8b and the
third portion 8c of the bottom pole layer 8 exposed, and the
insulating layer 11. In general, the insulating material used for
the recording gap layer 12 may be alumina, aluminum nitride, a
silicon-dioxide-base material, a silicon-nitride-base material, or
diamond-like carbon (DLC) and so on. The recording gap layer 12 may
be fabricated through sputtering or CVD. If the recording gap layer
12 made of alumina is fabricated through CVD, materials used are
trimethyl aluminum (Al(CH.sub.3).sub.3) and H.sub.2O, for example.
Through the use of CVD, it is possible to make the thin and precise
recording gap layer 12 with few pinholes.
[0075] Next, a portion of the recording gap layer 12 on the third
portion 8c of the bottom pole layer 8 is etched to form a contact
hole for making a magnetic path. In addition, a portion of the
recording gap layer 12 and the insulating layer 11 on the
connecting portion 10a of the coil 10 is etched to form a contact
hole.
[0076] Next, on the recording gap layer 12, a top pole layer 13
having a thickness of about 2.0 to 3.0 .mu.m is formed. The top
pole layer 13 extends from the air bearing surface 30 to the top
portion of the third portion 8c of the bottom pole layer 8. A
conductive layer 21 having a thickness of about 2.0 to 3.0 .mu.m is
formed to be connected to the portion 10b of the coil 10. The top
pole layer 13 is connected to the third portion 8c of the bottom
pole layer 8 through the contact hole formed in the top portion of
the third portion 8c.
[0077] The top pole layer 13 may be made of NiFe (80 weight % Ni
and 20 weight % Fe), or NiFe (45 weight % Ni and 55 weight % Fe) as
a high saturation flux density material through plating or may be
made of a material such as FeN or FeZrN as a high saturation flux
density material through sputtering. Alternatively, a material such
as CoFe or a Co-base amorphous material as a high saturation flux
density material may be used. To improve the high frequency
characteristic, the top pole layer 13 may be made of a number of
layers of inorganic insulating films and magnetic layers of
Permalloy, for example.
[0078] Next, as shown in FIG. 5A and FIG. 5B, the recording gap
layer 12 is selectively etched through dry etching, using the top
pole layer 13 as a mask. The dry etching may be reactive ion
etching (RIE) using a chlorine-base gas such as BCl.sub.2 or
Cl.sub.2, or a fluorine-base gas such as CF.sub.4 or SF.sub.6, for
example. Next, the second portion 8b of the bottom pole layer 8 is
selectively etched by about 0.3 .mu.m through argon ion milling,
for example. A trim structure as shown in FIG. 5B is thus formed.
The trim structure suppresses an increase in the effective track
width due to expansion of a magnetic flux generated during writing
in a narrow track.
[0079] Next, an overcoat layer 17 of alumina, for example, having a
thickness of 20 to 40 .mu.m is formed over the entire surface. The
surface of the overcoat layer 17 is then flattened and pads (not
shown) for electrodes are formed on the overcoat layer 17. Finally,
lapping of the slider including the foregoing layers is performed
to form the air bearing surfaces 30 of the recording head and the
reproducing head. The thin-film magnetic head of the embodiment is
thus completed.
[0080] In this embodiment the bottom pole layer 8 made up of the
first portion 8a, the second portion 8b and the third portion 8c
corresponds to a first magnetic layer of the invention. The top
pole layer 13 corresponds to a second magnetic layer of the
invention.
[0081] FIG. 6 is an explanatory view illustrating the
correspondence of a top view (shown in the upper part of FIG. 6)
and a cross-sectional view (shown in the lower part of FIG. 6) of
the main part of the thin-film magnetic head of the embodiment. The
overcoat layer 17 and other insulating layers and insulating films
are omitted in the top view of FIG. 6. In FIG. 6 `TH` indicates the
throat height. `TH0` indicates the zero throat height position.
`MR-H` indicates the MR height. `W` indicates the recording track
width.
[0082] In this embodiment, in a portion of the second portion 8b of
the bottom pole layer 8 that faces the top pole layer 13, an end of
this portion opposite to the air bearing surface 30 forms a
straight line parallel to the air bearing surface 30. An end of the
other portion of the second portion 8b that is opposite to the air
bearing surface 30 forms a circular arc similar to the shape of the
periphery of the thin-film coil 10. In the embodiment, as described
above, in the portion of the second portion 8b that faces the top
pole layer 13, the end of this portion opposite to the air bearing
surface 30 forms a straight line parallel to the air bearing
surface 30. As a result, the throat height and the zero throat
height position is precisely controlled.
[0083] In the embodiment the top pole layer 13 defines track width
W. As shown in FIG. 6, the top pole layer 13 has a first portion
13A, a second portion 13B and a third portion 13C, in the order in
which the closest to the air bearing surface 30 comes first. The
width of the first portion 13A is equal to track width W. The
second portion 13B is greater than the first portion 13A in width.
The third portion 13C is greater than the second portion 13B in
width. The width of the third portion 13C gradually decreases
toward the air bearing surface 30. The width of the second portion
13B gradually decreases toward the air bearing surface 30, too.
[0084] Edges of the top pole layer 13 connecting edges of the first
portion 13A at ends of its width to edges of the second portion 13B
at ends of its width are parallel to the air bearing surface 30.
Similarly, edges of the top pole layer 13 connecting edges of the
second portion 13B at ends of its width to edges of the third
portion 13C at ends of its width are parallel to the air bearing
surface 30.
[0085] In the top pole layer 13 the position of the interface
between the first portion 13A and the second portion 13B is located
near the zero MR height position (the position of an end of the MR
element 5 opposite to the air bearing surface 30).
[0086] In the top pole layer 13 the position of the interface
between the second portion 13B and the third portion 13C (the
position near the step between the second portion 13B and the third
portion 13C shown in FIG. 6) is located closer to the air bearing
surface 30 than zero throat height position TH0 (that is, located
on the left side of FIG. 6).
[0087] As described so far, the thin-film magnetic head of the
embodiment comprises the reproducing head and the recording head.
The reproducing head has: the MR element 5; and the bottom shield
layer 3 and the top shield layer (bottom pole layer 8) for
shielding the MR element 5. Portions of the bottom shield layer 3
and the top shield layer facing toward a recording medium are
opposed to each other, the MR element 5 being placed between the
portions.
[0088] The recording head has the bottom pole layer 8 (the first
portion 8a, the second portion 8b and the third portion 8c) and the
top pole layer 13 magnetically coupled to each other, each of which
is made up of at least one layer. The bottom pole layer 8 and the
top pole layer 13 includes pole portions opposed to each other and
placed in regions on a side of the head that faces toward a
recording medium. The recording head further has: the recording gap
layer 12 placed between the pole portion of the bottom pole layer 8
and the pole portion of the top pole layer 13; and the thin-film
coil 10 at least part of which is placed between the bottom pole
layer 8 and the top pole layer 13, the at least part of the coil
being insulated from the bottom pole layer 8 and the top pole layer
13.
[0089] In the embodiment the bottom pole layer 8 has: the first
portion 8a placed in a position facing at least part of the
thin-film coil 10; and the second portion 8b connected to a surface
of the first portion 8a facing the coil 10 (that is, the upper side
of the drawing). The second portion 8b forms the pole portion and
defines the throat height. The thin-film coil 10 is placed on a
side of the second portion 8b (that is, the right side of the
drawing).
[0090] In the embodiment the insulating layer 11 for insulating the
turns of the thin-film coil 10 from each other includes the first
insulating film 11a and the second insulating film 11b. The first
insulating film 11a is made of an insulating material that exhibits
fluidity during formation and touches the insulating film 9 as the
base layer of the coil 10. The first insulating film 11a is placed
to fill at least part of the space between the turns of the coil
10, the space between the second portion 8b of the bottom pole
layer 8 and the coil 10, and the space between the third portion 8c
of the bottom pole layer 8 and the coil 10. The second insulating
film 11b is made of an inorganic insulating material and placed to
cover the first insulating film 11a. The top surface of the second
insulating film 11b is flattened, together with the second portion
8b and the third portion 8c.
[0091] In the embodiment the thin-film coil 10 is placed on the
side of the second portion 8b of the bottom pole layer 8, and
formed on the flat insulating film 9. As a result, the fine
thin-film coil 10 is fabricated with precision, according to the
embodiment. Furthermore, an end of the coil 10 is placed near the
zero throat height position, that is, an end of the second portion
8b opposite to the air bearing surface 30 in the embodiment.
[0092] According to the embodiment as thus described, the yoke
length is reduced by about 30 to 40 percent of that of a prior-art
head, for example. As a result, the magnetomotive force generated
by the thin-film coil 10 is efficiently used for recording. It is
therefore possible to provide a thin-film magnetic head having a
recording head with an excellent high frequency characteristic, an
excellent nonlinear transition shift (NLTS) characteristic and an
excellent overwrite characteristic, according to the
embodiment.
[0093] Since the embodiment achieves a reduction in the yoke
length, the entire length of the coil 10 is reduced without
changing the number of turns. The resistance of the coil 10 is
thereby reduced. Consequently, it is possible to reduce the
thickness of the coil 10.
[0094] In the embodiment the insulating layer 11 for insulating the
turns of the thin-film coil 10 from each other includes the first
insulating film 11a and the second insulating film 11b. The first
insulating film 11a is made of an insulating material that exhibits
fluidity during formation and touches the insulating film 9 as the
base layer of the coil 10. The first insulating film 11a is placed
to fill at least part of the space between the turns of the coil
10, the space between the second portion 8b of the bottom pole
layer 8 and the coil 10, and the space between the third portion 8c
of the bottom pole layer 8 and the coil 10. The second insulating
film 11b is made of an inorganic insulating material and placed to
cover the first insulating film 11a.
[0095] As a result, according to the embodiment, the
above-mentioned spaces are completely filled with the first
insulating film 11a. It is thereby possible to prevent formation of
voids in the insulating layer 11. Since the second insulating film
11b made of an inorganic insulating material is placed to cover the
first insulating film 11a in the embodiment, it is possible to
prevent deformation of the insulating layer 11 with time. Because
of these features, the embodiment achieves an improvement in
reliability of the thin-film magnetic head.
[0096] The second insulating film 11b made of an inorganic
insulating material is placed to cover the first insulating film
11a in the embodiment. As a result, it is possible to prevent the
pole portion from protruding toward a recording medium because of
expansion due to heat generated around the coil 10, during the use
of the thin-film magnetic head. It is therefore possible to have
the slider flying near the recording medium. The characteristics of
the head is thereby improved.
[0097] According to the embodiment, the top surface of the second
insulating film 11b is flattened, together with the top surfaces of
the second portion 8b and the third portion 8c. As a result, the
top pole layer 13 that defines the recording track width is formed
on the flat surface. The top pole layer 13 is thus formed with
accuracy even though the track width is reduced to the half-micron
order or quarter-micron order. The track width is thereby precisely
controlled.
[0098] [Second Embodiment]
[0099] Reference is now made to FIG. 7A to FIG. 10A and FIG. 7B to
FIG. 10B to describe a thin-film magnetic head and a method of
manufacturing the same of a second embodiment of the invention.
FIG. 7A to FIG. 10A are cross sections each orthogonal to the air
bearing surface. FIG. 7B to FIG. 10B are cross sections each
parallel to the air bearing surface of the pole portion.
[0100] The steps performed until the thin-film coil 10 is formed in
the method of manufacturing the thin-film magnetic head of this
embodiment are similar to those of the first embodiment.
[0101] In the following step of the method of the second
embodiment, as shown in FIG. 7A and FIG. 7B, the first insulating
film 11a made of an insulating material that exhibits fluidity
during formation is made through photolithography, for example. The
first insulating film 11a is selectively formed to touch the
insulating film 9 as a base layer of the coil 10 and to fill the
space between the turns of the coil 10, the space between the
second portion 8b of the bottom pole layer 8 and the coil 10, and
the space between the third portion 8c of the bottom pole layer 8
and the coil 10, and to cover the coil 10.
[0102] Next, heat treatment is performed on the first insulating
film 11a to fill the above-mentioned spaces with the first
insulating film 11a completely, and to flatten the top surface of
the first insulating film 11a. For example, UV cure or annealing is
performed at a temperature in a range of 100 to 200.degree. C.
[0103] Next, as shown in FIG. 8A and FIG. 8B, at least a portion of
the first insulating film 11a located on top of the thin-film coil
10 is removed by etch back through anisotropic etching using a
CH.sub.4-base gas or O.sub.2 plasma. In this embodiment the first
insulating film 11a on which etch back has been performed may
either fill all of the above-mentioned spaces or fill part of the
spaces as shown in FIG. 8A and FIG. 8B.
[0104] Next, as shown in FIG. 9A and FIG. 9B, the second insulating
film 11b is formed to cover the first insulating film 11a. The
second insulating film 11b is made of an inorganic insulating
material and has a thickness of about 3 to 4 .mu.m, for example.
Next, the insulating film 11b is polished through CMP, for example,
until the second portion 8b and the third portion 8c of the bottom
pole layer 8 are exposed, and the surface is flattened.
[0105] In such a manner the insulating layer 11 for insulating the
space between the turns of the coil 10 is made of the first
insulating film 11a and the second insulating film 11b.
[0106] The following steps are similar to those of the first
embodiment. FIG. 10A and FIG. 10B are cross sectional views of the
thin-film magnetic head of the second embodiment.
[0107] The remainder of the configuration, operations and effects
of the embodiment are similar to those of the first embodiment.
[0108] [Third Embodiment]
[0109] Reference is now made to FIG. 11A to FIG. 14A, FIG. 11B to
FIG. 14B, and FIG. 15 to describe a thin-film magnetic head and a
method of manufacturing the same of a third embodiment of the
invention. FIG. 11A to FIG. 14A are cross sections each orthogonal
to the air bearing surface. FIG. 11B to FIG. 14B are cross sections
each parallel to the air bearing surface of the pole portion.
[0110] The steps performed until the insulating film 9 is formed in
the method of manufacturing the thin-film magnetic head of this
embodiment are similar to those of the first embodiment.
[0111] In the following step of the method of the third embodiment,
as shown in FIG. 11A and FIG. 11B, a first layer 31 of the
thin-film coil made of copper, for example, is formed through a
step similar to the step of forming the thin-film coil 10 of the
first embodiment. For example, the thickness of the first layer 31
is 0.8 to 1.5 .mu.m, the line width of the coil is 0.5 to 1.0
.mu.m, and the space between neighboring lines is 0.5 to 1.0 .mu.m.
Numeral 31a in the drawings indicates a portion for connecting the
first layer 31 to a second layer described of the thin-film coil
later.
[0112] Next, an insulating film 32a similar to the first insulating
film 11a is formed through a step similar to the step of forming
the first insulating film 11a of the first embodiment. Heat
treatment is then performed on the insulating film 32a.
[0113] Next, as shown in FIG. 12A and FIG. 12B, an insulating film
32b similar to the second insulating film 11b is formed through a
step similar to the step of forming the second insulating film 11b
of the first embodiment. The insulating film 32b is polished until
the second portion 8b and the third portion 8c of the bottom pole
layer 8 are exposed, and the surface is flattened.
[0114] In such a manner an insulating layer 32 for insulating the
space between the turns of the first layer 31 of the coil is made
of the insulating films 32a and 32b.
[0115] Next, as shown in FIG. 13A and FIG. 13B, the recording gap
layer 12 made of an insulating material whose thickness is about
0.15 to 0.20 .mu.m, for example, is formed on the second portion 8b
and the third portion 8c of the bottom pole layer 8 exposed, and
the insulating layer 32.
[0116] Next, a portion of the recording gap layer 12 located on the
third portion 8c of the bottom pole layer 8 is etched to form a
contact hole for making a magnetic path.
[0117] Next, on the recording gap layer 12, a pole portion layer
13a having a thickness of 2.0 to 3.0 .mu.m, for example, is
fabricated to form the pole portion of the top pole layer 13. A
magnetic layer 13b having a thickness of 2.0 to 3.0 .mu.m is formed
in the contact hole formed in the third portion 8c of the bottom
pole layer 8. The top pole layer 13 of this embodiment is made up
of the pole portion layer 13a and the magnetic layer 13b, and a
yoke portion layer 13c described later. The magnetic layer 13b is a
portion for connecting the yoke portion layer 13c to the third
portion 8c of the bottom pole layer 8.
[0118] The pole portion layer 13a and the magnetic layer 13b of the
top pole layer 13 may be made of NiFe (80 weight % Ni and 20 weight
% Fe), or NiFe (45 weight % Ni and 55 weight % Fe) as a high
saturation flux density material through plating, or may be made of
a material such as FeN or FeZrN as a high saturation flux density
material through sputtering. Alternatively, a material such as CoFe
or a Co-base amorphous material as a high saturation flux density
material may be used.
[0119] Next, the recording gap layer 12 is selectively etched
through dry etching, using the pole portion layer 13a of the top
pole layer 13 as a mask. The dry etching may be reactive ion
etching (RIE) using a chlorine-base gas such as BCl.sub.2 or
Cl.sub.2, or a fluorine-base gas such as CF.sub.4 or SF.sub.6, for
example. Next, the second portion 8b of the bottom pole layer 8 is
selectively etched by about 0.3 .mu.m through argon ion milling,
for example. A trim structure as shown in FIG. 13B is thus
formed.
[0120] Next, the recording gap layer 12 and the insulating layer 32
located on top of the connection portion 31a of the first layer 31
of the thin-film coil to form a contact hole.
[0121] Next, the second layer 34 of the thin-film coil made of
copper, for example, is formed by frame plating on the recording
gap layer 12 on a side of the pole portion layer 13a of the top
pole layer 13. For example, the thickness of the second layer 34 is
0.8 to 1.5 .mu.m, the line width of the coil is 0.5 to 1.0 .mu.m,
and the space between neighboring lines is 0.5 to 1.0 .mu.m.
Numeral 34a in the drawings indicates a portion for connecting the
second layer 34 of the coil to the first layer 31.
[0122] Next, an insulating film 35a made of an insulating material
that exhibits fluidity during formation is made through
photolithography, for example. The insulating film 35a is
selectively formed to touch the recording gap layer 12 as a base
layer of the second layer 34 of the coil and to fill the space
between the turns of the second layer 34, the space between the
pole portion layer 13a and the second layer 34, and the space
between the magnetic layer 13b and the second layer 34, and to
cover the second layer 34. The insulating film 35a may be made of
an organic insulating material such as a photoresist or may be a
spin-on-glass film.
[0123] Next, heat treatment is performed on the insulating film 35a
to fill the above-mentioned spaces with the insulating film 35a
completely, and to flatten the top surface of the insulating film
35a. For example, UV cure or annealing is performed at a
temperature in the range of 100 to 200.degree. C.
[0124] Next, as shown in FIG. 14A and FIG. 14B, an insulating film
35b is formed to cover the insulating film 35a. The insulating film
35b is made of an inorganic insulating material and has a thickness
of about 3 to 4 .mu.m, for example. The inorganic insulating
material for making the insulating film 35b may be alumina or
silicon dioxide. Next, the insulating film 35b is polished through
CMP, for example, until the pole portion layer 13a and the magnetic
layer 13b of the top pole layer 13 are exposed, and the surface is
flattened.
[0125] In such a manner an insulating layer 35 for insulating the
space between the turns of the second layer 34 of the coil is made
of the insulating films 35a and 35b.
[0126] Next, the yoke portion layer 13c having a thickness of 2.0
to 3.0 .mu.m, for example, is formed on the flattened pole portion
layer 13a and magnetic layer 13b of the top pole layer 13 and
insulating layer 35. The yoke portion layer 13c is provided for the
recording head and made of a magnetic material. The yoke portion
layer 13c is in contact with the third portion 8c of the bottom
pole layer 8 through the magnetic layer 13b and magnetically
coupled thereto. The yoke portion layer 13c may be made of NiFe (80
weight % Ni and 20 weight % Fe), or NiFe (45 weight % Ni and 55
weight % Fe) as a high saturation flux density material through
plating or may be made of a material such as FeN or FeZrN as a high
saturation flux density material through sputtering. Alternatively,
a material such as CoFe or a Co-base amorphous material as a high
saturation flux density material may be used. To improve the high
frequency characteristic, the yoke portion layer 13c may be made of
a number of layers of inorganic insulating films and magnetic
layers of Permalloy, for example.
[0127] In this embodiment an end face of the yoke portion layer 13c
of the top pole layer 13 on a side of the air bearing surface 30 is
located at a distance from the air bearing surface 30 (the right
side of FIG. 14A).
[0128] Next, an overcoat layer 37 of alumina, for example, having a
thickness of 20 to 40 .mu.m is formed over the entire surface. The
surface of the overcoat layer 37 is then flattened and pads (not
shown) for electrodes are formed on the overcoat layer 37. Finally,
lapping of the slider including the foregoing layers is performed
to form the air bearing surfaces 30 of the recording head and the
reproducing head. The thin-film magnetic head of the embodiment is
thus completed.
[0129] In this embodiment the top pole layer 13 made up of the pole
portion layer 13a, the magnetic layer 13b and the yoke portion
layer 13c corresponds to the second magnetic layer of the
invention. The pole portion layer 13a corresponds to a second
portion of the magnetic layer of the invention. The yoke portion
layer 13c corresponds to a first portion of the magnetic layer of
the invention.
[0130] FIG. 15 is an explanatory view illustrating the
correspondence of a top view (shown in the upper part of FIG. 15)
and a cross-sectional view (shown in the lower part of FIG. 15) of
the main part of the thin-film magnetic head of the embodiment. The
overcoat layer 37 and other insulating layers and insulating films
are omitted in the top view of FIG. 15. In FIG. 15 `TH` indicates
the throat height. `TH0` indicates the zero throat height position.
`MR-H` indicates the MR height. `W` indicates the recording track
width.
[0131] As shown in FIG. 15, the pole portion layer 13a of the top
pole layer 13 has a first portion 13a.sub.1 located closer to the
air bearing surface 30, and a second portion 13a.sub.2 coupled to
the first portion 13a.sub.1 and located at a distance from the air
bearing surface 30. The width of the first portion 13a.sub.1 is
equal to recording track width W. The second portion 13a.sub.2 is
greater than the first portion 13a.sub.1 in width. The interface
between the first portion 13a.sub.1 and the second portion
13a.sub.2 (that is, the position of the step between the first
portion 13a.sub.1 and the second portion 13a.sub.2) is located near
zero throat height position TH0.
[0132] The width of a portion of the yoke portion layer 13c of the
top pole layer 13 overlaid on the pole portion layer 13a is equal
to the width of the pole portion layer 13a. The width of the yoke
portion layer 13c increases toward the side opposite to the air
bearing surface 30 and then maintains a specific width.
[0133] According to the third embodiment thus described, the first
layer 31 of the thin-film coil is placed on a side of the second
portion 8b of the bottom pole layer 8, and formed on the flat
insulating film 9. Furthermore, the top surface of the insulating
layer 32 for insulating the turns of the first layer 31 of the coil
from each other is flattened, together with the top surface of the
second portion 8b. On the flattened surfaces, the recording gap
layer 12 is placed on which the pole portion layer 13a and the
second layer 34 of the coil are formed. The second layer 34 is
located on a side of the pole portion layer 13a. As a result, both
the first layer 31 and the second layer 34 of the coil are formed
into minute sizes with accuracy. In addition, an end of the first
layer 31 is located near an end of the second portion 8b of the
bottom pole layer 8, and end of the second layer 34 is located near
an end of the pole portion layer 13a of the top pole layer 13. As a
result, the yoke length is further reduced in the third embodiment,
compared to the first embodiment, since the thin-film coil is made
up of two layers.
[0134] In the third embodiment the insulating layer 32 for
insulating the turns of the first layer 31 of the thin-film coil
from each other includes the insulating film 32a and the insulating
film 32b. The insulating film 32a is made of an insulating material
that exhibits fluidity during formation and touches the insulating
film 9 as the base layer of the first layer 31. The insulating film
32a is formed to fill at least part of the space between the turns
of the first layer 31, the space between the second portion 8b of
the bottom pole layer 8 and the first layer 31, and the space
between the third portion 8c of the bottom pole layer 8 and the
first layer 31. The insulating film 32b is made of an inorganic
insulating material and placed to cover the insulating film
32a.
[0135] In this embodiment the insulating layer 35 for insulating
the turns of the second layer 34 of the thin-film coil from each
other includes the insulating film 35a and the insulating film 35b.
The insulating film 35a is made of an insulating material that
exhibits fluidity during formation and touches the recording gap
layer 12 as the base layer of the second layer 34. The insulating
film 35a is formed to fill at least part of the space between the
turns of the second layer 34, the space between the pole portion
layer 13a of the top pole layer 13 and the second layer 34, and the
space between the magnetic layer 13b of the top pole layer 13 and
the second layer 34. The insulating film 35b is made of an
inorganic insulating material and placed to cover the insulating
film 35a.
[0136] As a result, according to the embodiment, as in the first
embodiment, it is possible to prevent formation of voids in the
insulating layers 32 and 35. It is also possible to prevent
deformation of the insulating layers 32 and 35 with time. The
reliability of the thin-film magnetic head is thereby improved. In
addition, as in the first embodiment, it is possible to prevent the
pole portion from protruding toward a recording medium because of
expansion due to heat generated around the first layer 31 and the
second layer 34 of the coil, during the use of the thin-film
magnetic head. It is therefore possible to have the slider flying
near the recording medium. The characteristics of the head are
thereby improved.
[0137] According to the embodiment, the first layer 31 of the coil
is placed on a side of the second portion 8b of the bottom pole
layer 8. In addition, the top surface of the insulating layer 32
for insulating the turns of the first layer 31 from each other is
flattened, together with the top surface of the second portion 8b.
As a result, the pole portion layer 13a of the top pole layer 13
that defines the recording track width is formed on the flat
surface. The pole portion layer 13a is thus formed with accuracy
even though the track width is reduced to the half-micron order or
quarter-micron order. The track width is thereby precisely
controlled.
[0138] According to the embodiment, the second layer 34 of the coil
is placed on a side of the pole portion layer 13a of the top pole
layer 13. In addition, the top surface of the insulating layer 35
for insulating the turns of the second layer 34 from each other is
flattened, together with the top surface of the pole portion layer
13a. As a result, the yoke portion layer 13c of the top pole layer
13 is formed on the flat surface, too. The yoke portion layer 13c
is thereby formed into small dimensions. It is thus possible to
prevent so-called side write that allows writing of data in a
region where data is not expected to be written.
[0139] In the embodiment the end face of the yoke portion layer 13c
on a side of the air bearing surface 30 is located at a distance
from the air bearing surface. As a result, the yoke portion layer
13c is prevented from being exposed in the air bearing surface 30
even if the throat height is small. Side write is thereby
prevented.
[0140] The insulating films 32 and 35 may be formed through steps
similar to those of the insulating layer 11 of the second
embodiment. The remainder of the configuration, operations and
effects of the embodiment are similar to those of the first
embodiment.
[0141] The present invention is not limited to the foregoing
embodiments but may be practiced in still other ways. For example,
in the foregoing embodiments, the thin-film magnetic head is
disclosed, comprising the MR element for reading formed on the base
body and the induction-type magnetic transducer for writing stacked
on the MR element. Alternatively, the MR element may be stacked on
the magnetic transducer.
[0142] That is, the induction-type magnetic transducer for writing
may be formed on the base body and the MR element for reading may
be stacked on the transducer. Such a structure may be achieved by
forming a magnetic film functioning as the top pole layer of the
foregoing embodiments as a bottom pole layer on the base body, and
forming a magnetic film functioning as the bottom pole layer of the
embodiments as a top pole layer facing the bottom pole layer with a
recording gap film in between. In this case it is preferred that
the top pole layer of the induction-type magnetic transducer
functions as the bottom shield layer of the MR element as well.
[0143] The invention may be applied to a thin-film magnetic head
having only an induction-type magnetic transducer for performing
both reading and writing.
[0144] According to the thin-film magnetic head or the method of
manufacturing the same of the invention described so far, at least
one of the magnetic layers includes: the first portion located in a
position facing at least part of the thin-film coil; and the second
portion forming the pole portion and connected to a surface of the
first portion that faces the thin-film coil. At least part of the
coil is placed on a side of the second portion. It is thereby
possible that an end of at least part of the coil is located near
an end of the second portion. As a result, the yoke length is
reduced. In the invention the insulating layer for insulating the
turns of at least part of the thin-film coil from each other
includes the first insulating film and the second insulating film.
The first insulating film is made of an insulating material that
exhibits fluidity during formation and touches the base layer of
the at least part of the coil. The first insulating film is placed
to fill at least part of the space between the turns of the at
least part of the coil and the space between the second portion and
the at least part of the coil. The second insulating film is made
of an inorganic insulating material and placed to cover the first
insulating film. As a result, it is possible to prevent generation
of voids in the insulating layer insulating the turns of the
thin-film coil from each other.
[0145] The surface of the second insulating film opposite to the
first insulating film may be flattened. In this case, the layer
formed on the second insulating film is fabricated with
precision.
[0146] 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.
* * * * *