Dynamic magnetic information storage or retrieval – Head – Core
Reexamination Certificate
2000-03-22
2002-10-15
Cao, Allen (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Core
C360S125020
Reexamination Certificate
active
06466403
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thin film magnetic head and a manufacturing method for the same and, more particularly, to a thin film magnetic head having a very narrow track width of 1 &mgr;m or less, and a manufacturing method for the same.
2. Description of the Related Art
FIG. 26
shows a conventional flying magnetic head
150
.
The flying magnetic head
150
is primarily constructed by a slider
151
and a composite thin film magnetic head
157
provided on the slider
151
. Reference numeral
155
denotes a reading end of the slider
151
that is an upstream end of a direction in which a magnetic recording medium moves, while reference numeral
156
denotes a trailing end. Rails
151
a
,
151
a
, and
151
b
are formed on a medium opposing surface
152
of the slider
151
, air grooves
151
c
and
151
c
being provided between the rails.
The composite thin film magnetic head
157
is provided on an end surface
151
d
at the trailing end
156
of the slider
151
.
Referring to
FIGS. 27 and 28
, the composite thin film magnetic head
157
is comprised of an MR magnetic head h
1
equipped with a magnetoresistive device and a thin film magnetic head h
2
, which is a write head. These magnetic heads h
1
and h
2
are deposited on the end surface
151
d
of the slider
151
.
The MR magnetic head h
1
is comprised of a lower shield layer
163
that is formed on the end surface
151
d
of the slider
151
and composed of a magnetic alloy, a read gap layer
164
deposited on the lower shield layer
163
, a magnetoresistive device
165
exposed on the medium opposing surface
152
, an upper shield planarizing gap layer
166
covering the magnetoresistive device
165
and the read gap layer
164
, and an upper shield layer
167
covering the upper shield planarizing gap layer
166
.
The upper shield layer
167
serves also as a lower core layer of the thin film magnetic head h
2
.
The MR magnetic head h
1
is employed as a read magnetic head. When a minute leakage magnetic field from a magnetic recording medium is applied to the magnetoresistive device
165
, resistance in the magnetoresistive device
165
changes. A voltage change based on the change in the resistance is read as a reproduction signal of the magnetic recording medium by the MR magnetic head h
1
.
The thin film magnetic head h
2
is formed of a lower core layer or the upper shield layer
167
, a gap layer
174
deposited on the lower core layer
167
, a coil
176
formed in a back region Y of the gap layer
174
, an upper insulation layer
177
covering the coil
176
, and an upper core layer
178
that is joined to the gap layer
174
in a magnetic pole tip region X and joined to the lower core layer
167
in the back region Y.
The coil
176
is patterned so that it is flatly spiral. In a substantially central portion of the coil
176
, a proximal end portion
178
b
of the upper core layer
178
is magnetically connected to the lower core layer
167
.
A protective layer
179
composed of alumina or the like is deposited on the upper core layer
178
.
The lower core layer
167
, the gap layer
174
, and the upper core layer
178
extend from the back region Y toward the magnetic pole tip region X in the composite thin film magnetic head
157
, and are exposed on the medium opposing surface
152
. In the medium opposing surface
152
, the upper core layer
178
and the lower core layer
167
face each other with the gap layer
174
sandwiched therebetween, forming a magnetic gap.
The magnetic pole tip region X is an area where the upper core layer
178
and the lower core layer
167
are separated by only the gap layer
174
sandwiched therebetween in the vicinity of the medium opposing surface
152
. The back region Y refers to an area excluding the magnetic pole tip region X.
The foregoing thin film magnetic head h
2
is used as a write head. When a recording current is applied to the coil
176
, magnetic fluxes are generated in the upper core layer
178
and the lower core layer
167
by the recording current. The magnetic fluxes leak out through the magnetic gap to produce a leakage magnetic field, and the leakage magnetic field causes the magnetic recording medium to be magnetized to thereby record a recording signal.
To fabricate the thin film magnetic head h
2
, the lower core layer
167
, the gap layer
174
, and the upper core layer
178
are formed in this order by a depositing pattern in advance. In this case, the upper core layer
178
is processed according to a frame plating method using plating and ion milling. A width of the upper core layer
178
exposed to the medium opposing surface
152
is determined by a resist width in the frame plating method or the like, the plating, and an etching method, and the width of the upper core layer
178
exposed on the medium opposing surface
152
determines a magnetic recording track width.
Thus, a track width of a magnetic recording medium can be reduced by providing a smaller magnetic recording track width of the thin film magnetic head h
2
, i.e., the width of the upper core layer
178
at the magnetic pole tip exposed on the medium opposing surface. This makes it possible to achieve a higher track density of the magnetic recording medium, consequently permitting a higher recording density.
In the conventional thin film magnetic head h
2
, however, the upper core layer is thick. Therefore, even when the layers are accurately formed by the frame plating or other means and the magnetic pole tip is processed with the highest possible processing accuracy currently available, it is difficult to accomplish a recording track width of 1 &mgr;m or less due to a limited resolution of exposure when forming a resist pattern. This has been a problem in that a further higher recording density of a magnetic recording medium cannot be achieved.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made with a view toward solving the problem described above, and it is an object thereof to provide a thin film magnetic head having a recording track width of 1 &mgr;m or less. It is another object thereof to provide a method for manufacturing a thin film magnetic head having a recording track width of 1 &mgr;m or less.
To fulfill the foregoing objects, the present invention adopts the following configurations.
According to one aspect of the present invention, there is provided a thin film magnetic head including: an upper core layer and a lower core layer that extend from a back region toward a magnetic pole tip region, end surfaces thereof being exposed on a medium opposing surface, and the upper core layer and the lower core layer being magnetically connected in the back region; and a gap layer provided between the upper core layer and the lower core layer in the magnetic pole tip region; wherein an insulation layer is deposited on the lower core layer; a groove extending from the medium opposing surface toward the back region is provided in the magnetic pole tip region of the insulation layer, the groove being composed of a groove main body that opens to the lower core layer, the upper core layer, and the medium opposing surface, and a slant portion formed in the opening of the groove main body at the end of the upper core layer; a lower magnetic pole layer, the gap layer, and an upper magnetic pole layer are deposited in the groove; and the lower magnetic pole layer is joined to the lower core layer, while the upper magnetic pole layer is joined to the upper core layer, the upper magnetic pole layer forming an upper magnetic pole tip, while the lower magnetic pole layer forms a lower magnetic pole tip.
In a preferred form of the present invention, the groove main body of the thin film magnetic head is equipped with two side walls that are installed in a standing manner on the lower core layer and reach the medium opposing surface, and a magnetic pole tip surface that connects the two side walls at the back region side of the groove main body and defines gap depths of the upper magnetic pole tip and
Kuriyama Toshihiro
Sato Kiyoshi
Watanabe Toshinori
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Cao Allen
Nguyen Dzung
LandOfFree
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