Dynamic magnetic information storage or retrieval – Head – Coil
Reexamination Certificate
2001-03-14
2002-08-13
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Coil
C360S125330
Reexamination Certificate
active
06433960
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 an inductive type writing magnetic head and a method of manufacturing the same.
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. In order to satisfy such a requirement, there has been proposed a magnetic head, in which a reading or reproducing magnetic head and a writing or recording magnetic head are stacked one on the other. In such a magnetic head, an inductive type thin film magnetic head is used as the writing head and a magnetoresistive type thin film magnetic head is used as the reading head. As the magnetoresistive type magnetic head, a magnetoresistive element having a conventional anisotropic magnetoresistive (AMR) effect has been widely utilized. There has been further developed a magnetoresistive 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, these AMR and GMR elements are termed as a magnetoresistive reproducing element or MR reproducing element.
By using the AMR element, a very high surface recording density of several gigabits per a unit square inch can be 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 small in size.
A height of a magnetoresistive reproducing element (MR Height: MRH) is one of factors which determine a performance of a reproducing head including a magnetoresistive reproducing element. This MR height MRH is a distance measured from an air bearing surface on which the magnetoresistive reproducing element exposes to an 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.
As stated above, a performance of the reproducing head may be improved by utilizing the GMR element. Then, a performance of a recording head is required to be improved accordingly. In order to increase a surface recording density, it is necessary to make a track density on a magnetic record medium as high as possible. For this purpose, a width of a pole portion and write gap at the air bearing surface has to be reduced to a value within a range from several microns to several submicrons. In order to satisfy such a requirement, the semiconductor manufacturing process has been utilized in manufacturing the thin film magnetic head.
One of factors determining a performance of the inductive type thin film writing magnetic film 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. This distance can be also determined by controlling an amount of polishing the air bearing surface.
In order to improve a performance of the inductive type thin film writing magnetic head, it has been proposed to shorten a length of portions of bottom pole and top pole surrounding the thin film coil (in this specification, said length is called a magnetic path length).
FIGS. 1-8
are cross sectional views showing successive steps of a known method of manufacturing a conventional typical combination type thin film magnetic head including a GMR element, said cross sectional views being cut along a plane perpendicular to the air bearing surface. In this example, the combination type thin film magnetic head is constructed by stacking an inductive type writing thin film magnetic head on a magnetoresistive type reading thin film magnetic head.
At first, as illustrated in
FIG. 1
, on a substrate
1
made of a non-magnetic material such as AlTiC, is deposited an insulating layer
2
made of alumina (Al
2
O
3
) and having a thickness of about 5-10 &mgr;m, a bottom shield layer
3
constituting a magnetic shield for the MR reproducing magnetic head and having a thickness of about 3-4 &mgr;m is deposited on the insulating layer, and then a GMR layer
5
having a thickness not larger than several tens nm is formed such that the GMR layer is embedded in a shield gap layer
4
. On the shield gap layer
4
, is further deposited a magnetic layer
6
made of a permalloy and having a thickness of 3-4 &mgr;m. This magnetic layer
6
serves not only as an upper shield layer for magnetically shielding the GMR reproducing element together with the above mentioned bottom shield layer
3
, but also as a bottom magnetic layer of the inductive type writing thin film magnetic head. Here, for the sake of explanation, the magnetic layer
6
is called a first magnetic layer, because this magnetic layer constitutes one of magnetic layers forming the writing thin film magnetic head.
Next, as shown in
FIG. 2
, on the first magnetic layer
6
, is formed a write gap layer
7
made of a nonmagnetic material such as alumina with a thickness of about 200 nm. A photoresist layer
8
for determining a throat height TH is formed on the write gap layer
7
except for a portion which will constitute a pole portion, and then a thin copper layer
9
having a thickness of about 100 nm is deposited on a whole surface by sputtering. The copper layer
9
will serve as a seed layer for a process of forming a thin film coil by an electroplating, and thus this layer is also called a seed layer. On this seed layer
9
, is formed a thick photoresist layer
10
having a thickness of 3 &mgr;m, and openings
11
are formed in the photoresist layer such that the seed layer
9
is exposed in the openings. A height of the openings is 2 &mgr;m which is identical with a thickness of the photoresist layer and a width of the openings is also 2 &mgr;m.
Next, an electroplating of copper is performed using an electroplating liquid of a copper sulfate to form coil windings
12
of a first thin film coil layer within the openings
11
formed in the photoresist layer
10
, said coil windings having a thickness of 2-3 &mgr;m. A thickness of the coil windings
12
is preferably smaller than a depth of the openings
11
.
Then, as depicted in
FIG. 4
, after removing the photoresist layer
10
, a milling process is conducted with an argon ion beam to remove the seed layer
9
as shown in
FIG. 5
such that the coil windings
12
are separated from each other to form a single body of a coil. During the ion beam milling, in order to avoid that a part of the seed layer
9
situating underneath the bottoms of the coil windings
12
is remained to extend from the thin film coil, the ion beam milling is performed with an incident angle of 5-10°. When the ion beam milling is carried out with substantially upright angles, a material of the seed layer
9
which is spread by an impact of the ion beam is liable to be adhered to surroundings. Therefore, a distance between successive coil windings
12
has to be large.
Next, as illustrated in
FIG. 6
, a photoresist layer
13
is formed such that the coil windings
12
of the first thin film coil layer are covered with this photoresist layer, and after polishing a surface to be flat, coil windings
15
of a second thin film coil layer is formed on a seed layer
14
by the same process as that described above. After forming a photoresist layer
16
, a second magnetic layer
17
made of a permalloy is formed to have a thickness of 3-7 &mgr;m, said second magnetic layer constituting a top pole.
Next, as shown in
FIGS. 7 and 8
, the write gap layer
7
and a surface of the first magnetic layer
6
are etched to form a trim structure, while a pole portio
Oliff & Berridg,e PLC
TDK Corporation
Tupper Robert S.
LandOfFree
Method of manufacturing a magnetic head 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 a magnetic head, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of manufacturing a magnetic head will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2897726