Dynamic magnetic information storage or retrieval – Fluid bearing head support – Disk record
Reexamination Certificate
1999-11-09
2001-07-03
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Fluid bearing head support
Disk record
C360S245800
Reexamination Certificate
active
06256170
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to thin film magnetic heads and to manufacturing processes therefor. More particularly, the present invention relates to a thin film magnetic head having a plurality of closely spaced wires connecting a head device with bonding pads, and to a manufacturing process therefor.
2. Description of the Related Art
FIGS. 5A
to
5
C are drawings illustrating a conventional thin film magnetic head.
FIG. 5A
is a perspective view of the conventional thin film magnetic head,
FIG. 5B
is a cross-sectional view of the conventional thin film magnetic head along the line
5
B—
5
B in
FIG. 5A
, and
FIG. 5C
is a partial perspective cross-sectional view of an important portion of the conventional thin film magnetic head.
FIGS. 6A and 6B
are drawings illustrating a pattern of wires in the conventional thin film magnetic head.
FIG. 6A
is a schematic plan view of the wires in the conventional thin film magnetic head, and
FIG. 6B
is a cross-sectional view of the conventional thin film magnetic head along the line
6
B—
6
B in FIG.
6
A.
FIGS. 7A
to
7
D and
FIGS. 8A
to
8
D are plan views and cross-sectional views of the conventional thin film magnetic head illustrating a production process therefor.
FIG. 9
is a cross-sectional view of an important portion of another conventional thin film magnetic head.
A slider
1
of the thin film magnetic head mounted on a magnetic memory unit such as a hard disk, which is composed of a ceramic such as alumina-titanium carbide (Al
2
O
3
. TiC), has an air bearing surface (ABS)
1
a
(a floating surface; a surface opposing a magnetic memory medium) in the form of rails and a trailing side surface
1
b
as shown in FIG.
5
A. On the trailing side surface
1
b
, there are provided a head device
2
and four bonding pads
3
to be connected to peripheral circuits.
As shown in
FIG. 5B
, the head device
2
is a so-called “complex thin film magnetic head”, which is composed of a magnetoresistive magnetic head
2
a
(hereinafter referred to as an “MR head”) for reading and an inductive magnetic head
2
b
(hereinafter, referred to as an “inductive head”) for writing laminated on the MR head. The MR head
2
a
includes a lower sealed layer
2
a
1
composed of a Ni—Fe type alloy (Permalloy) laminated on the trailing side surface
1
b
of the slider
1
, a lower gap layer
2
a
2
composed of a nonmagnetic material such as Al
2
O
3
laminated on the lower sealed layer
2
a
1
, a magnetoresistive element
2
a
3
disposed at the center of the upper surface of the lower gap layer
2
a
2
, hard-bias layers (not shown) formed on both sides of the magnetoresistive element
2
a
3
as vertical biases, two conductive layers
2
a
4
(not shown) composed of a nonmagnetic conductive material such as Cr disposed on the upper surfaces of the hard bias layers, an upper gap layer
2
a
5
composed of a nonmagnetic material such as Al
2
O
3
disposed on the upper layer of the magnetoresistive element
2
a
3
and the upper surface of the conductive layer
2
a
4
, and an upper sealed layer
2
a
6
composed of a magnetic material such as a Ni—Fe type alloy (Permalloy) disposed on the upper surface of the upper gap layer
2
a
5
.
As shown in
FIGS. 5B and 5C
, the inductive head
2
b
includes a lower core layer
2
b
1
which is also used as the upper sealed layer
2
a
6
of the MR head
2
a
, a nonmagnetic material layer
2
b
2
for forming a gap provided at the upper part of the lower core layer
2
b
1
, a first coil-insulating layer
2
b
3
composed of an organic resin material or the like laminated on the nonmagnetic material layer
2
b
2
, a flat helicoid coil
2
b
4
composed of a low resistance conductive material such as Cu disposed on the upper part of the first coil-insulating layer
2
b
3
, a second coil-insulating layer
2
b
5
disposed so as to cover the coil
2
b
4
, and an upper core layer
2
b
6
composed of a magnetic material such as a Ni—Fe type alloy (Permalloy). The upper core layer
2
b
6
at one end thereof contacts the nonmagnetic material layer
2
b
2
at the ABS surface
1
a
side, and is connected at the other end of the upper core layer
2
b
6
to the lower core layer
2
b
1
around the center C of the flat helicoid coil
2
b
4
through a hole H provided at the second coil-insulating layer
2
b
5
.
As shown in
FIG. 6A
, four wires
4
(
4
a
,
4
b
,
4
c
, and
4
d
) composed of a low resistance conductive material such as nickel (Ni) or copper (Cu) are disposed on the trailing side surface
1
b
which is the side portion of the head device
2
, and each wire
4
has at one end thereof a wider end terminal E. The two wires
4
a
and
4
b
are connected at the other ends thereof to two ends of a coil
2
b
4
(a peripheral end and a central end), and the other two wires
4
c
and
4
d
are connected at the other ends thereof to the two conductive layers
2
a
4
of the MR head
2
a
, respectively (a connected state is not shown). The four wires are disposed in parallel in parts thereof, and are adjacent each other with minute spaces Sa in parallel parts thereof. As shown in
FIG. 6B
, a ground layer for plating
5
composed of a conductive material such as a Ni—Fe type alloy (Permalloy) is disposed so as to cover the upper and side parts of the four end terminals E, and a bump base
6
composed of a Ni—Fe type alloy (Permalloy) or the like is laminated on the ground layer for plating
5
disposed on the end terminal portion E. Four bumps
7
are disposed on the four bump bases
6
, and each bump is composed of a conductive material such as Ni or Cu and has a vertical contact portion
7
a
to contact the bump base
6
and a brim
7
b
with wider tails.
As shown in
FIG. 6B
, a protection layer
8
composed of Al
2
O
3
or the like is disposed on the entire surface of the trailing side surface
1
b
of the slider
1
in the state of covering the upper layers of the wires
4
, the bumps
7
, etc. By polishing the trailing side surface
1
b
, parts of the brims
7
b
of the four bumps
7
are exposed, and on each exposed upper part thereof is formed a bonding pad
3
composed of gold by a plating method. Thus, the four bonding pads
3
and the head device
2
are electrically connected, and the thin film magnetic head is thereby formed.
Next, a manufacturing process for the conventional thin film magnetic head will be explained. The lower core layer
2
b
1
composed of a Ni—Fe type alloy (Permalloy) and the nonmagnetic material layer
2
b
2
are laminated sequentially on the MR head
2
a
formed on the trailing side surface
1
b
of the slider
1
, and then the first coil-insulating layer
2
b
3
is formed (not shown) with coating an organic resin material and the like on a nonmagnetic layer
2
b
2
by a photolithographic method. As shown in
FIG. 7A
(plan view) and
FIG. 7B
(cross-sectional view along the line
7
B—
7
B in FIG.
7
A), by using photo-lithographic and plating methods, the wires
4
(
4
a
,
4
b
,
4
c
, and
4
d
) having end terminals E are formed on the slider
1
in the same step for forming the coil
2
b
4
by the use of copper or the like on the first coil insulating layer
2
b
3
.
Next, as shown in
FIG. 7C
(plan view), by coating an organic resin material and the like so as to cover the coil
2
b
4
, the second coil-insulating layer
2
b
5
is formed on the upper surface of the first coil-insulating layer
2
b
3
by a photolithographic method. The second coil-insulating layer
2
b
5
around the center C (see
FIGS. 5
b
and
5
c
) of the coil
2
b
4
is provided with the hole H which reaches the lower core layer
2
b
1
.
The ground layer for plating
5
composed of a Ni—Fe type alloy (Permalloy) or the like is formed by a method such as sputtering or deposition on the upper layers of the head device
2
and the wires
4
, and on the entire surface of the trailing side surface
1
b
inside the hole H. The ground layer for plating
5
can be formed only on the areas where the upper core
2
b
6
, the bump bases
6
, and the bumps
7
are to be form
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Tupper Robert S.
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