Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2000-08-30
2004-11-02
Chang, Richard (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S603140, C029S603070, C029S603230
Reexamination Certificate
active
06810578
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thin film magnetic head and a method of manufacturing the same, and more particularly to a composite type thin film magnetic head constructed by stacking an inducting type writing magnetic transducing element and a magnetoresistive type reading magnetic transducing element, particularly a technique for improving a performance of a thin film writing magnetic head.
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.
The composite type thin film magnetic head has a structure for stacking a recording head intended for the writing and a reproducing head intended for the reading out, and a magnetoresistive element has been widely used in order to improve the performance of the reproducing head.
In general, as such a magnetoresistive element, the element utilizing anisotropic magnetoresistive (AMR) effect has been used so far, but there has been further developed a GMR reproducing element utilizing a giant magnetoresistive (GMR) effect having a resistance change ratio higher than the normal anisotropic magnetoresistive effect by several times. In the present specification, elements exhibiting a magnetoresistive effect such as these AMR and GMR reproducing elements are termed as a magnetoresistive reproducing element or MR reproducing element.
By using the AMR reproducing element, a very high surface recording density of several gigabits per a unit square inch has been realized, and a surface recording density can be further increased by using the GMR element. By increasing a surface recording density in this manner, it is possible to realize a hard disc device which has a very large storage capacity of more than 10 gigabytes and is still small in size. A height (MR Height: MRH) of a magnetoresistive reproducing element is one of factors which determine a performance of a reproducing head including a magnetoresistive reproducing element. The MR height MRH is a distance measured from an air bearing surface on which one end face of the magnetoresistive reproducing element is exposed to the other edge of the element remote from the air bearing surface. During a manufacturing process of the magnetic head, a desired MR height MRH can be obtained by controlling an amount of polishing the air bearing surface.
At the same time, a performance of a recording head is also required to be improved, in accordance with improvement of performance of the reproducing head. In order to increase a surface recording density, it is en necessary to make a track density on a magnetic record medium as high as possible. For this purpose, a width of a write gap at the air bearing surface has to be reduced to a value within a range from several micron meters to several sub-micron meters. In order to satisfy such a requirement, the semiconductor manufacturing process has been adopted for manufacturing the thin film magnetic head.
One of factors determining a performance of an inductive type thin film writing magnetic head is a throat height TH. This throat height TH is a distance of a pole portion measured from the air bearing surface to an edge of an insulating layer which serves to separate a thin film coil from the air bearing surface. It has been required to shorten this distance as small as possible. The reduction of this throat height is also decided by the amount of grinding from the air bearing surface. Therefore, in order to improve the performance of the thin film magnetic recording head, it is important that the recording head and the reproducing head are formed with best balance.
FIGS. 1
a
,
1
b
-
9
a
, and
9
b
are cross-sectional views vertical to the air bearing surface showing the successive manufacturing steps of a conventional standard thin film magnetic head, and a cross sectional view in which the magnetic pole section is cut in parallel to the air bearing surface. Moreover
FIGS. 10-12
are a cross-sectional view of the entire conventional completed thin film magnetic head a cross-sectional view of the magnetic pole section, and a plan view of the entire thin film magnetic head, respectively. Moreover, the thin film magnetic head of this embodiment is a composite type thin film magnetic head formed by stacking the induction type thin film writing magnetic head and the MR reproduction reading element.
First of all, as shown in
FIGS. 1
a
and
1
b
, an Insulation layer
2
consisting of for example alumina (Al
2
O
3
) is deposited on a basic substrate consisting of non-magnetic and electrical insulation material for example, such as AlTiC with a thickness of about 5-10 &mgr;m.
Next, as shown in
FIGS. 2
a
and
2
b
, a lower shield layer
3
which composes a magnetic shield protecting the MR reproduction element of the reproducing head from the influence of the external magnetic field, is formed with the thickness of 3 &mgr;m.
Afterwards, as shown in
FIGS. 3
a
and
3
b
after spattering and depositing alumina as a shield gap layer
4
of a thickness of 100-150 nm, a magnetic resistance layer
5
consisting of a material with the effect of magnetic resistance and composing the MR reproduction element is formed on the shield gap layer with a thickness of tens nano meter, thereby making high precise mask alignment.
Then as shown in the
FIG. 4
, again, a shield gap layer
6
is formed so that the magnetic resistance layer
5
is embedded in the shield gap layers
4
and
6
.
Next, as shown in the
FIG. 5
, a magnetic layer
7
consisting of permalloy is formed with the film thickness of 3 &mgr;m. This magnetic layer
7
has not only a function of the upper shield layer which magnetically shields the MR reproduction element together with the above described lower shield layer
3
, but also has a function of a lower magnetic layer of the thin film magnetic writing head. Herein, for convenience sake of the explanation, this magnetic layer
7
is called as a first magnetic layer by paying attention to it a magnetic layer composing a writing magnetic head.
Then, on the first magnetic layer
7
, after a light gap layer
8
consisting of non-magnetic material, for example alumina is formed with film thickness of about 200 nm, a second magnetic layer
9
consisting of material with high saturation magnetic flux density such as, for example, permalloy (Ni: 50 wt %, Fe: 50 wt %) and nitride iron (FeN) is formed with a desired shape by high precise mask alignment.
Second ma molded in a given shape is called a pole chip, and the width of the track is defined as a width W.
In this case, when a dummy pattern
9
′ for connecting a lower pole (first magnetic layer) and an upper pole (third magnetic layer), which is formed latter, are formed simultaneously, it is possible to make an opening for through-hole after a polishing or chemistry-mechanical (CMP).
In order to prevent a width of effective writing track from being widened, that is, in order to prevent a magnetic flux from being widened in the lower pole at the data writing, also a gap layer
8
in surroundings of the pole chip
9
and the lower pole
7
(first magnetic layer) are etched by an ion beam etching, such as, ion miring. Even though its state is shown in
FIG. 5
b
, this structure is called as a trim, and this portion becomes a magnetic pole section in the first magnetic layer.
Next, as shown in
FIGS. 6
a
and
6
b
, after an insulating layer, for example, alumina film
10
is formed with the thickness of about 3 &mgr;m, the whole is, for example, made smooth by CMP.
Subsequently, after forming a photoresist layer
11
of electrical insulation to a given pattern by the mask alignment of high precision, a thin film coil
12
as the first layer consisting, for example, of copper is formed on the photoresist layer
11
.
Continuously, as shown in
FIGS. 7
a
and
7
b
, after forming an insulating photoresist layer
13
is formed on the thin film coil
12
by the mask alignment of high accu
Fukuda Kazumasa
Iijima Atsushi
Sasaki Yoshitaka
Chang Richard
Oliff & Berridg,e PLC
TDK Corporation
LandOfFree
Method of manufacturing thin film magnetic head with... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of manufacturing thin film magnetic head with..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of manufacturing thin film magnetic head with... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3285581