Dynamic magnetic information storage or retrieval – Head – Core
Reexamination Certificate
2001-01-16
2004-01-27
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Core
C360S123090
Reexamination Certificate
active
06683750
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a recording thin film magnetic head used as, for example, a flying magnetic head, or the like, and particularly, to a thin film magnetic head in which the magnetic path can be shortened to decrease inductance, and withstand voltage between a lower core layer and a coil layer can be improved, and a manufacturing method therefor.
2. Description of the Related Art
FIG. 36
is a partial longitudinal sectional view showing the structure of a conventional thin film magnetic head (inductive head).
In
FIG. 36
, reference numeral
1
denotes a lower core layer made of a magnetic material such as permalloy, or the like, and a recording region
12
is formed on the lower core layer
1
near the surface facing a recording medium.
The recording region
12
comprises, for example, a gap layer
4
and an upper pole layer
4
made of a magnetic material.
In addition, a coil layer
5
is formed on the rear region of the upper core layer
1
, which is behind the recording region in the height direction (the Y direction shown in FIG.
36
).
Furthermore, the pitch intervals of a conductor of the coil layer
5
is filled with an insulation layer
11
, and an insulation layer
7
made of an organic material or the like is formed on the coil layer
5
and the insulation layer
11
.
As shown in
FIG. 36
, an upper core layer
8
made of permalloy or the like is formed in the region from the recording region
12
to the insulation layer
7
so that the front end
8
a
of the upper core layer
8
is magnetically connected to the upper top pole layer
4
, and the base end
8
b
is magnetically connected to the lower core layer
1
. As shown in
FIG. 36
, the front end of the upper core layer
8
may be formed at a position shifted backward from the surface facing the recording medium, or exposed from the surface facing the recording medium.
This thin film magnetic head has a construction in which the coil layer
5
is provided behind the recording region
12
in the height direction so that the magnetic path ranging from the upper core layer
8
to the lower core layer
1
can be shortened to decrease inductance, thereby making adaptable to a higher recording density in future.
As shown in
FIG. 36
, an insulation underlying layer
9
is formed between the coil layer
5
and the lower core layer
1
to maintain electric insulation between the coil layer
5
and the lower core layer
1
.
However, the thin film magnetic head shown in
FIG. 36
causes the following problems.
Since the coil layer
5
must be formed behind the recording region
12
in the height direction (the Y direction shown in FIG.
36
), the insulation underlying layer
9
must be thinly formed between the coil layer
5
and the lower core layer
1
, thereby failing to sufficiently maintain withstand voltage between the coil layer
5
and the lower core layer
1
.
The insulation underlying layer
9
is thinly formed by sputtering using an inorganic insulating material, for example, such as Al
2
O
3
, or the like.
However, in depositing the thin film by sputtering, the insulation underlying layer
9
is easily contaminated with dust particles (impurities) present in a sputtering apparatus to decrease the withstand voltage of the insulation underlying layer
9
.
Also, in forming the thin insulation underlying layer
9
by sputtering, pinholes or the like easily occur in the insulation underlying layer
9
, thereby further decreasing the withstand voltage.
Conversely, when the thick insulation underlying layer
9
is formed to a thickness sufficient to secure the withstand voltage between the lower core layer
1
and the coil layer
5
, and the coil layer
5
is formed so that the upper surfaces of the coil layer
5
and the recording region
12
lie in substantially the same plane, as shown in
FIG. 36
, the coil layer
5
is thinned, and thus the width dimension T
1
of the coil layer
5
must be increased from the viewpoint of decreasing the coil resistance value. Therefore, the magnetic path ranging from the upper core layer
8
to the lower core layer
1
is lengthened to increase inductance, thereby failing to manufacture a thin film magnetic head adaptable to a higher recording density.
Even when the thick insulation underlying layer
9
is formed, the withstand voltage of the insulation underlying layer
9
cannot be effectively improved due to the above-described contamination with dust particles during sputtering.
SUMMARY OF THE INVENTION
The present invention has been achieved for solving the above-described problems of a conventional magnetic head, and an object of the present invention is to provide a thin film magnetic head in which the magnetic path can be shortened to decrease inductance, and the withstand voltage between a coil layer and a lower core layer can be improved, and a manufacturing method therefor.
In order to achieve the object, the present invention provides a thin film magnetic head comprising a lower core layer, an upper core layer, a recording region comprising a pole layer and a gap layer located between the lower and upper core layers in the surface facing a recording medium, and a coil layer formed on the rear portion of the lower core layer, which is behind the recording region in the height direction, for inducing a recording magnetic field in the lower core layer, the upper core layer and the recording region, wherein at least an organic insulation underlying layer is interposed between the lower core layer and the coil layer.
In the present invention, the organic insulation underlying layer made of an organic material having high withstand voltage is formed between the lower core layer and the coil layer, thereby effectively improving the withstand voltage between the lower core layer and the coil layer.
Even with the thin organic insulation underlying layer, pinholes less occur to permit the formation of the thin insulation underlying layer having high withstand voltage, as compared with a conventional insulation underlying layer made of an inorganic insulating material.
More specifically, in the present invention, an inorganic insulation underlying layer is formed on the lower core layer, the organic insulation underlying layer is formed on the inorganic insulation underlying layer, and the coil layer is formed on the organic insulation underlying layer.
Alternatively, the organic insulation underlying layer is formed on the lower core layer, the inorganic insulation underlying layer is formed on the organic insulation underlying layer, and the coil layer is formed on the inorganic insulation underlying layer.
Namely, the insulation underlying layer comprising the two layers, i.e., the organic insulation underlying layer and the inorganic insulation underlying layer, is formed between the lower core layer and the coil layer. This can appropriately improve the withstand voltage between the lower core layer and the coil layer, as compared with the conventional insulation underlying layer comprising a single layer.
Where the inorganic insulation underlying layer is a lower layer, and the organic insulation underlying layer is an upper layer, the pinholes formed in the inorganic insulation underlying layer are appropriately filled with the organic insulation underlying layer to effectively improve the withstand voltage.
In the present invention, the inorganic insulation underlying layer is preferably made of at least one inorganic insulating material of AlO, Al
2
O
3
, SiO
2
, Ta
2
O
3
, TiO, AlN, AlSiN, TiN, SiN, Si
3
N
4
, NiO, WO, WO
3
, BN, CrN, SiON, and AlSiO.
The organic insulation underlying layer is preferably made of resist or polyimide.
In the present invention, the thickness of the inorganic insulation underlying layer is preferably in the range of 0.15 &mgr;m to 0.5 &mgr;m.
The thickness of the organic insulation underlying layer is preferably in the range of 0.2 &mgr;m to 1.0 &mgr;m.
Furthermore, in the present invention, the gap between the lower core layer and the coil layer is preferably in the ran
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Tupper Robert S.
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