Dynamic magnetic information storage or retrieval – Head – Magnetoresistive reproducing head
Reexamination Certificate
2002-02-08
2004-10-05
Ometz, David (Department: 2653)
Dynamic magnetic information storage or retrieval
Head
Magnetoresistive reproducing head
C360S125330
Reexamination Certificate
active
06801407
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thin film magnetic bead and a method of manufacturing the same, and more particularly relates to a combination type thin film magnetic head having an inductive type writing thin film magnetic head element including a thin film coil and a magnetoresistive type reading thin film magnetic head element stacked one on the other, and a method of manufacturing the same. More particularly, the present invention relates to a combination type thin film magnetic head and a method of manufacturing the same, in which a GMR element is used as a magnetoresistive type thin film magnetic head element and an inductive type thin film magnetic head element has a superior NTSL property by extremely shortening a magnetic path length by reducing a coil winding pitch of a thin film coil and has a narrow record track for attaining a high surface recording density on a magnetic record medium by providing a miniaturized track pole made of a magnetic material having a high saturation magnetic flux density.
2. Description of the Related Art
Recently a surface recording density of a hard disc device has been improved, and it has been required to develop a thin film magnetic head having an improved performance accordingly. A recent magnetoresistive type thin film magnetic head using a GMR (Giant Magneto-Resistive) element has a surface recording density up to 100 gigabits/inch
2
. A combination type thin film magnetic head is constructed by stacking an inductive type thin film magnetic head intended for writing information on a magnetic record medium and a magnetoresistive type thin film magnetic head intended for reading information out of the magnetic record medium on a substrate. As a reading magneto-resistive element, a GMR element having a magnetoresistive change larger than a normal anisotropic MR element by 5-15 times has been used. In order to improve a performance of the GMR element, there have been various proposals.
In a normal anisotropic MR element, a single film of a magnetic material showing the magnetoresistive effect is utilized. Many GMR elements have a multi-layer structure having a stack of a plurality of films. A spin-valve GMR film has a relatively simple structure, generates a large resistance change under a weak magnetic field, and is suitable for a large scale manufacture. A performance of the reading head element is determined by not only the above mentioned selection of materials, but also by pattern widths such as an MR height and a track width. The track width is determined by a photolithography process and the MR height is determined by an amount of polishing for forming an air bearing surface (ABS).
At the same time, the performance of the recording magnetic head is also required to be improved in accordance with the improvement of the performance of the reproducing magnetic head. In order to increase a surface recording density, it is necessary to realize a high track density on a magnetic record medium. To this end, a pole portion of the recording thin film magnetic head element has to be narrowed in a sub-micron order, particularly not larger than 0.2 &mgr;m by utilizing the semiconductor manufacturing process. However, upon decreasing a track width by utilizing the semiconductor manufacturing process, there is a problem that a sufficiently large magnetic flux could not be obtained due to a miniaturized structure of the pole portion. In this manner, by replacing the MR film by the GMR film in the reproducing head element and by selecting a material having a high magnetoresistive sensitivity, it is possible simply to attain a desired high surface recording density.
In order to realize a sufficiently high surface recording density of about 100 gigabits/inch
2
, it is necessary to use a record medium, i.e. a magnetic disk material having a high magnetic coercive force. If a magnetic material having a high coercive force is not used, once recorded data might be erased due to the thermal fluctuation. When a material magnetic having a high coercive force is used, recoding requires a large magnetic flux, and therefore a inductive type thin film magnetic head element must generate a large magnetic flux. Generally, in order to generate a large magnetic flux in the inductive type thin film magnetic head element, a track pole is made of a magnetic material having a high saturation magnetic flux density (Hi-Bs material having a saturation magnetic flux density not less than 1.8 T (tesla). NiFe (80:20) of 1.0 T and NiFe (45:55) have been used as a magnetic material having a high saturation magnetic flux density. Recently, CoNiFe of 1.8~2.0 T has been used. In order to use a miniaturized track pole stably, a magnetic material having saturation magnetic flux density of about 1.8 T is generally used. However, when a width of the track pole is reduced to sub-micron order, such magnetic materials could not generate a sufficiently large magnetic flux for recording stably. In this manner, it is required to use a magnetic material having a higher saturation magnetic flux density. Heretofore, when a track pole is made of a magnetic material having a high saturation magnetic flux density, a plating method has been generally used. However, in order to manufacture a track pole having a narrow width, it is preferable to use a sputtering method. From this view point, it will be advantageous to form a track pole by sputtered films of FeN having a saturation magnetic flux density of 2.0 T FeCo of 2.4 T.
FIGS. 1-9
are cross sectional views showing successive steps of a method of manufacturing a conventional combination type thin film magnetic head. In these drawings, A represents a cross sectional view cut along a plane perpendicular to the air bearing surface and B denotes a cross sectional view of a pole portion cut along a plane parallel to the air bearing surface. The combination type thin film magnetic head includes an inductive type recording magnetic head element provided on a magnetoresistive type reading magnetic head element.
As shown in
FIGS. 1A and 1B
, an alumina (Al
2
O
3
) insulating film
2
having a thickness of about 2-3 &mgr;m is deposited on a substance
1
made of AlTiC. Next, a bottom shield film
3
made of a magnetic material for magnetically shielding a GMR reading head element from an external magnetic field on the substrate. On the bottom shield film
3
, a shield gap film
4
made of alumina is formed with a thickness of 30-35 nm by sputtering. Then, a GMR film
5
having a given layer-structure is formed, and lead electrodes
6
for the GMR film are formed by a lift-off process. Next, a top shield gap film
7
made of alumina is formed with a thickness of 30-35 nm by sputtering, and a magnetic material film
8
serving as a top shield film is formed with a thickness of about 3 &mgr;m.
Next, an isolation film
9
made of alumina is formed with a thickness of about 0.3 &mgr;m for isolating the reading GMR head element from a writing induction type thin film magnetic head element to suppress noise in a reproduced output from the GMR head element. After that, a bottom pole
10
of the recording head element made of permalloy is formed with a thickness of 1.5-2.0 &mgr;m. The bottom pole
10
is formed by a plating film of CoNiFe. It should be noted that in the drawings a ratio of thickness of various portions does not exactly correspond to an actual ratio. For instance, the isolation film
9
is shown to have a smaller thickness.
Next, as depicted in
FIGS. 2A and 2B
, on the bottom pole
10
, is formed a write gap film
11
made of a non-magnetic material to have a thickness of about 100 nm, and a top track pole
12
made of a permalloy which is a magnetic material having a high saturation magnetic flux density is formed in accordance with a given pattern. At the same time, a bridge portion
13
for magnetically coupling the bottom pole
10
with a top pole to be formed later at a back-gap is formed. The top track pole
12
and bridge portion
13
are formed by plating with a thickness of
Kamigama Takehiro
Sasaki Yoshitaka
Headway Technologies, Incorporated
Oliff & Berridg,e PLC
Ometz David
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