Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2000-11-01
2003-08-12
Vo, Peter (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S603160, C360S119050, C360S125330, C451S028000
Reexamination Certificate
active
06604275
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a thin-film magnetic head provided with at least an inductive recording transducer element and a method of manufacturing the head.
DESCRIPTION OF THE RELATED ART
Recently, demand for higher recording density has made a recording track width narrower, and therefore a submicron width of the pole of the recording head part has been needed. To cope with such narrower pole width, a thin-film magnetic head is formed in a manner that only the recording pole portion is separated from other portions. That is, a three-layer pole tip structure with a lower pole tip element, a recording gap layer and an upper pole tip element is formed at only a pole tip region located between an air bearing surface (ABS) and a position at a predetermined height from the ABS in the recording head part, and an upper yoke and a lower yoke are magnetically connected to the top surface and the bottom surface of this pole tip structure, respectively.
FIG. 1
is a schematic ABS view, illustrating an example of a conventional composite type thin-film magnetic head with an inductive recording head part and a magnetoresistive (MR) reproducing head part.
In the figure, the reference numeral
10
denotes a lower shield layer of the MR reproducing head part,
11
denotes an upper shield layer of the MR head part, which also acts as a lower auxiliary pole of an inductive recording head part,
12
denotes a MR layer provided through an insulating layer
13
between the lower shield layer
10
and the upper shield layer
11
,
14
denotes a lower pole tip element of the inductive recording head part,
15
denotes an upper pole tip element,
16
denotes a recording gap layer formed between the lower and upper pole tip elements
14
and
15
,
17
denotes an insulating layer deposited on the upper shield layer
11
and around a three-layer pole tip structure consisting of the lower pole tip element
14
, the recording gap layer
16
and the upper pole tip element
15
, and
18
denotes an upper auxiliary pole formed on the insulating layer
17
and deposited to contact with the upper pole tip element
15
. The upper auxiliary pole
18
is magnetically connected with the lower auxiliary pole (upper shield layer)
11
at its rear portion so as to constitute a magnetic yoke together with the lower auxiliary pole
11
.
The head with the three-layer pole tip structure shown in
FIG. 1
can realize a narrower track width. However, peeling is liable to occur at the interface between the upper pole tip element
15
and the upper auxiliary pole
18
which are located at the trailing side and act an important role during recording. Also, since the three-layer pole structure has a narrow pole width of submicron, the magnetic domain, i.e. the easy magnetization axis, directs to a longitudinal direction of the poles causing the recording current to magnetic field conversion efficiency to lower.
FIG. 2
is a schematic ABS view illustrating another example of a conventional composite type thin-film magnetic head having a three-layer pole structure, described in U.S. Pat. No. 5,452,164, and
FIG. 3
is a cross-sectional view perpendicular to the plane of the ABS, illustrating the example of FIG.
2
.
In
FIG. 2
, the reference numeral
20
denotes a lower shield layer of the MR reproducing head part,
21
denotes an upper shield layer of the MR head part, which also acts as a lower auxiliary pole of an inductive recording head part,
22
denotes a MR layer provided through an insulating layer
23
between the lower shield layer
20
and the upper shield layer
21
,
24
denotes a lower pole tip element of the inductive recording head part,
25
denotes an upper pole tip element,
26
denotes a recording gap layer formed between the lower and upper pole tip elements
24
and
25
,
27
denotes a lower insulating layer deposited on the upper shield layer
21
and around a three-layer pole structure consisting of the lower pole tip element
24
, the recording gap layer
26
and the upper pole tip element
25
,
28
denotes an upper auxiliary pole,
29
denotes a coil conductor formed on the lower insulating layer
27
, and
30
denotes an upper insulating layer covering the coil conductor
29
, respectively. In this example, the three-layer pole tip structure protrudes from the upper surface of the lower insulating layer
27
at a region near the ABS. The upper auxiliary pole
28
is formed to cover the protruded portion of the upper pole tip element
25
of the pole tip structure. This upper auxiliary pole
28
is magnetically connected with the lower auxiliary pole (upper shield layer)
21
at its rear portion so as to constitute a magnetic yoke together with the lower auxiliary pole
21
.
However, according to the conventional structure shown in
FIGS. 2 and 3
, the top of the lower insulating layer
27
at a region on which the coil conductor
29
is formed, which is far from the ABS, is formed so that it is certainly higher than the top of the three-layer pole tip structure. Thus, it is difficult to efficiently release heat generated by the recording current flowing through the coil conductor
29
. In general, it is necessary that heat from the coil conductor
29
is released outward via a metal member to enhance the reliability of the magnetic head. However, because the upper auxiliary pole
28
has small volume, it is insufficient to radiate the heat. In addition, because the lower insulating layer
27
is thick at this region under the upper auxiliary pole
28
, it is difficult to efficiently transmit the heat to the upper shield layer
21
.
Furthermore, because of the aforementioned conventional structure in which height in the top of the upper pole tip element
15
is the same as that of the insulating layer
17
, peeling often occurs at the interface between the upper pole tip element
15
and the upper auxiliary pole
18
.
Also, the conventional method for manufacturing the three-layer pole tip structure shown in
FIGS. 2 and 3
causes its fabricating processes to be very complicated.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a thin-film magnetic head and a method of manufacturing the head, whereby decrease in reliability derived from generation of heat can be effectively prevented.
Another object of the present invention is to provide a thin-film magnetic head and a method of manufacturing the head, whereby peeling at the interface between the upper pole tip element and the upper auxiliary pole can be prevented.
Further object of the present invention is to provide a thin-film magnetic head and a method of manufacturing the head, whereby manufacturing processes can be simplified.
According to the present invention, a thin-film magnetic head having an air bearing surface, includes a three-layer pole tip structure consisting of a lower pole tip element, a recording gap layer and an upper pole tip element, the structure having side surfaces, a rear surface and top surface, a lower auxiliary pole, a part of which contacts to the lower pole tip element, an upper auxiliary pole, a part of which contacts to the upper pole tip element, the upper auxiliary pole being magnetically connected at its rear portion with respect to the air bearing surface to the lower auxiliary pole so as to form a yoke together with the lower auxiliary pole, a lower insulating layer, surrounding the side surfaces and the rear surfaces of the three-layer pole tip structure, the lower insulating layer being located between the lower and upper auxiliary poles and having a top surface, a coil conductor formed on the top surface of the lower insulating layer, and an upper insulating layer covering the coil conductor, a part of the upper insulating layer being located between the lower insulating layer and the upper auxiliary pole. The top surface of the lower insulating layer is leveled lower than the top surface of the three-layer pole tip structure over at least a region within which the coil conductor is formed.
Since the top surface of the lower insulating lay
Kondo Masahiro
Matsukuma Koji
Mino Tetsuya
Terunuma Koichi
Uno Yasufumi
Arent Fox Kintner & Plotkin & Kahn, PLLC
Nguyen Donghai
TDK Corporation
Vo Peter
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