Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2000-10-12
2002-10-29
Fetsuga, Robert M. (Department: 3751)
Metal working
Method of mechanical manufacture
Electrical device making
C029S603180, C360S235400
Reexamination Certificate
active
06470565
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing a slider of a thin-film magnetic head which comprises a medium facing surface that faces toward a recording medium and a thin-film magnetic head element located near the medium facing surface.
2. Description of the Related Art
Performance improvements in thin-film magnetic heads have been sought as areal recording density of hard disk drives has increased. Such thin-film magnetic heads include composite thin-film magnetic heads that have been widely used. A composite head is made of a layered structure including a recording head having an induction magnetic transducer for writing and a reproducing head having a magnetoresistive (MR) element for reading. MR elements include an anisotropic magnetoresistive (AMR) element that utilizes the AMR effect and a giant magnetoresistive (GMR) element that utilizes the GMR effect. A reproducing head using an AMR element is called an AMR head or simply an MR head. A reproducing head using a GMR element is called a GMR head. An AMR head is used as a reproducing head where areal density is more than 1 gigabit per square inch. A GMR head is used as a reproducing head where areal density is more than 3 gigabits per square inch. It is GMR heads that have been most widely used recently.
The performance of the reproducing head is improved by replacing the AMR film with a GMR film and the like having an excellent magnetoresistive sensitivity. Alternatively, a pattern width such as the reproducing track width and the MR height, in particular, may be optimized. The MR height is the length (height) between an end of the MR element located in the air bearing surface and the other end. The air bearing surface is a surface of the thin-film magnetic head facing toward a magnetic recording medium.
Performance improvements in a recording head are also required as the performance of a reproducing head is improved. It is required to increase the linear density in order to increase the areal density among the performance characteristics of the recording head. To achieve this, it is required to implement a recording head of a narrow track structure wherein the width of top and bottom poles sandwiching the recording gap layer on a side of the air bearing surface is reduced down to microns or a submicron order. This width is one of the factors that determine the recording head performance. Semiconductor process techniques are utilized to implement such a structure. Another factor is a pattern width such as the throat height, in particular. The throat height is the length (height) of pole portions, that is, portions of magnetic pole layers facing each other with a recording gap layer in between, between the air-bearing-surface-side end and the other end. A reduction in throat height is desired in order to improve the recording head performance. The throat height is controlled by an amount of lapping when the air bearing surface is processed.
As thus described, it is important to fabricate well-balanced recording and reproducing heads to improve the performance of the thin-film magnetic head.
In order to implement a thin-film magnetic head that achieves high recording density, the requirements for the reproducing head include a reduction in reproducing track width, an increase in reproducing output, and a reduction in noise. The requirements for the recording head include a reduction in recording track width, an improvement in overwrite property that is a parameter indicating one of characteristics when data is written over existing data, and an improvement in nonlinear transition shift (NLTS).
In general, a flying-type thin-film magnetic head used in a hard disk device and the like is made up of a slider, a thin-film magnetic head element being formed at the trailing edge of the slider. The slider slightly floats over a recording medium by means of the airflow generated by the rotation of the medium.
Reference is now made to
FIG. 23A
to
FIG. 26A
,
FIG. 23B
to
FIG. 26B
, and
FIG. 27
to describe an example of a manufacturing method of a related-art thin-film magnetic head element.
FIG. 23A
to
FIG. 26A
are cross sections each orthogonal to the air bearing surface.
FIG. 23B
to
FIG. 26B
are cross sections of the pole portion each parallel to the air bearing surface.
According to the manufacturing method, as shown in FIG.
23
A and
FIG. 23B
, an insulating layer
102
made of alumina (Al
2
O
3
), for example, having a thickness of about 5 to 10 &mgr;m, is deposited on a substrate
101
made of aluminum oxide and titanium carbide (Al
2
O
3
—TiC), for example. Next, on the insulating layer
102
, a bottom shield layer
103
made of a magnetic material is formed for a reproducing head.
Next, a bottom shield gap film
104
made of an insulating material such as alumina and having a thickness of 100 to 200 nm, for example, is formed through sputtering on the bottom shield layer
103
. On the bottom shield gap film
104
, an MR element
105
for reproduction having a thickness of tens of nanometers is formed. Next, a pair of electrode layers
106
are formed on the bottom shield gap film
104
. The electrode layers
106
are electrically connected to the MR element
105
.
Next, a top shield gap film
107
made of an insulating material such as alumina is formed through sputtering, for example, on the bottom shield gap film
104
, the MR element
105
and the electrode layers
106
. The MR element
105
is embedded in the shield gap films
104
and
107
.
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
is formed. The bottom pole layer
108
has a thickness of about 3 &mgr;m and is made of a magnetic material and used for both the reproducing head and the recording head.
Next, as shown in FIG.
24
A and
FIG. 24B
, a recording gap layer
109
made of an insulating film such as an alumina film and having a thickness of 0.2 &mgr;m is formed on the bottom pole layer
108
. Next, the recording gap layer
109
is partially etched to form a contact hole
109
a
for making a magnetic path. Next, a top pole tip
110
for the recording head is formed on the recording gap layer
109
in the pole portion. The top pole tip
110
is made of a magnetic material and has a thickness of 0.5 to 1.0 &mgr;m. At the same time, a magnetic layer
119
made of a magnetic material is formed for making the magnetic path in the contact hole
109
a
for making the magnetic path.
Next, as shown in FIG.
25
A and
FIG. 25B
, 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. 25B
, the structure is called a trim structure wherein the sidewalls of the top pole portion (the top pole tip
110
), the recording gap layer
109
, and a part of the bottom pole layer
108
are formed vertically in a self-aligned manner.
Next, an insulating layer
111
of alumina, for example, having a thickness of about
3
Jim is formed over the entire surface. The insulating layer
111
is polished to the surfaces of the top pole tip
110
and the magnetic layer
119
and flattened.
On the flattened insulating layer
111
a first layer
112
of a thin-film coil is made for the induction-type recording head. The thin-film coil
112
is made of copper (Cu), for example. Next, a photoresist layer
113
is formed into a specific shape on the insulating layer
111
and the first layer
112
of the coil. Heat treatment is performed at a specific temperature to flatten the surface of the photoresist layer
113
. Next, a second layer
114
of the thin-film coil is formed on the photoresist layer
113
. Next, a photoresist layer
115
is formed into a specific shape on the photoresist layer
113
and the second layer
114
of the coil. Heat treatment is performed at a specific temperature to flatten the surface of the photoresist layer
115
.
Next, as shown in FIG.
26
A and
FIG. 26B
, a top pole layer
116
for the
deVore Peter
Fetsuga Robert M.
TDK Corporation
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