Dynamic magnetic information storage or retrieval – Fluid bearing head support – Disk record
Reexamination Certificate
1999-12-23
2003-05-13
Nguyen, Hoa T. (Department: 2652)
Dynamic magnetic information storage or retrieval
Fluid bearing head support
Disk record
C360S123090
Reexamination Certificate
active
06563674
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to thin-film magnetic heads used for magnetic writing/reading apparatuses and the like.
2. Description of the Related Art
FIGS. 5A and 5B
are drawings illustrating a magnetic writing/reading apparatus using a conventional thin-film magnetic head.
FIG. 5A
is a cross-sectional view of a main portion of the magnetic writing/reading apparatus, and
FIG. 5B
is a perspective view of a slider.
FIGS. 6
to
10
are schematic plan views of trailing side surfaces of the sliders used for conventional thin-film magnetic heads.
In a magnetic writing/reading apparatus such as a hard disk apparatus, a plurality of thin magnetic disks
51
are stacked in spaced relation to one another, and a pair of magnetic heads H facing each other are disposed over and under the magnetic disk
51
therebetween.
As shown in
FIGS. 5A and 5B
, the magnetic head H comprises a supporting member
52
composed of a leaf spring, a flexible printed circuit, or the like, and two sliders (an upper slider
53
a
and a lower slider
53
b
) mounted at the edges of the supporting member
52
. Sliders
53
a
and
53
b
are composed of a ceramic material, such as aluminum titanium carbide (Al
2
O
3
.TiC). An example shown in
FIG. 5B
is a so-called “two-rail slider” (lower slider
53
b
) having a U-shape in cross-section. On trailing side surface Ta of slider
53
a
, there are provided head element
54
a
and four bonding pads
55
a
1
to
55
a
4
composed of thin films which work as connecting terminals to peripheral processing circuits (not shown). Similarity to the above, on trailing side surface Tb of slider
53
b
, there are provided head element
54
b
and four bonding pads
55
b
1
to
55
b
4
composed of thin films which work as connecting terminals to peripheral processing circuits (not shown).
Head elements
54
a
and
54
b
are so-called “combined thin-film magnetic heads” comprising magnetoresistive magnetic heads (hereinafter referred to as an MR head) for reading and inductive magnetic heads (hereinafter referred to as an inductive head) for writing laminated on the MR heads. In
FIG. 6
, the MR heads comprise MR elements (not shown) and conductive layers Ea
1
and Ea
2
, connected to the two ends of one of the MR elements (not shown), and Eb
1
and Eb
2
, connected to the two ends of the other MR element (not shown). Conductive layers at bonding pads
55
a
4
and
55
b
4
sides are designated Ea
1
and Eb
1
, respectively. The inductive heads comprise flat helicoid coils Ca and Cb which are composed of a low resistance conductive material, such as nickel (Ni) or copper (Cu), and are covered by insulating layers (not shown).
In individual sliders
53
a
and
53
b
, four leads
56
a
1
to
56
a
4
, and four leads
56
b
1
to
56
b
4
are composed of a low resistance conductive material, such as nickel (Ni) or copper (Cu), and are provided at head element
54
a
side on trailing side surface Ta and at head element
54
b
side on trailing side surface Tb, as shown in FIG.
6
. An end of lead
56
a
1
is connected to the central edge of coil Ca through an upper connecting lead
57
a
which is provided on an insulating layer (not shown) so as to pass over coil Ca. An end of lead
56
b
1
is connected to the central edge of coil Cb through an upper connecting lead
57
a
which is provided on an insulating layer (not shown) so as to pass over coil Cb. Individual ends of leads
56
a
2
and
56
b
2
are connected to the peripheral edges of coils Ca and Cb. Coils Ca and Cb are located at bonding pads
55
a
4
and
55
b
4
sides, respectively. Individual ends of leads
56
a
3
and
56
b
3
are connected to conductive layers Ea
1
and Eb
1
, which are located at the bonding pads
55
a
4
and
55
b
4
sides. Individual ends of leads
56
a
4
and
56
b
4
are connected to other conductive layers Ea
2
and Eb
2
, through contact holes (not shown). The other ends of four leads
56
a
1
to
56
a
4
are connected to bonding pads
55
a
1
to
55
a
4
provided at the upper layers of the leads, and four leads
56
b
1
to
56
b
4
are connected to bonding pads
55
b
1
to
55
b
4
provided at the upper layers of the leads. Individual bonding pads
55
a
1
to
55
a
4
, and
55
b
1
to
55
b
4
, are provided with fine gold wires (not shown), and are connected to peripheral processing circuits (not shown). Signal currents for writing by the inductive heads are fed from bonding pads
55
a
1
and
55
a
2
, and
55
a
1
and
55
b
2
, and currents (sense currents) for reading by the magnet heads are fed from bonding pads
55
a
3
and
55
a
4
, and
55
b
3
and
55
b
4
.
A method for manufacturing a conventional thin-film magnetic head will be explained. On the MR heads formed on trailing side surfaces Ta of slider
53
a
and Tb of slider
53
b
, lower core layers (upper shield layers; not shown) composed of Ni—Fe based alloy (Permalloy), layers composed of a non-magnetic material (not shown), and first insulating layers (not shown) are formed, sequentially. Then, coils Ca and Cb composed of copper or the like are formed on the first insulating layers (not shown) by a method of photolithography and plating. In the same step mentioned above, leads
56
a
1
to
56
a
4
, and
56
b
1
to
56
b
4
, are formed on the same layers. Leads
56
a
1
and
56
b
1
are formed so as to be connected to the peripheral ends of the coil Ca and Cb at the sides thereof. Leads
56
a
3
and
56
a
4
are connected through contact holes (not shown) provided beforehand to two conductive layers Ea
1
and Ea
12
which are connected to one MR element, and leads
56
b
3
and
56
b
4
are connected through contact holes (not shown) provided beforehand to two conductive layers Eb
1
and Eb
2
which are connected to the other MR element. Individual ends of leads
56
a
2
and
56
b
2
are disposed at coils Ca and Cb sides, respectively.
Next, second insulating layers (not shown) are formed so as to cover coils Ca and Cb by a method of photolithography after coating an organic resinous material or the like thereon. Contact holes (not shown) leading to the central edges of coils Ca and Cb are provided in the second insulating layers. Then, upper core layers (not shown) are formed on the second insulating layers (not shown) by using Ni—Fe based alloy (Permalloy) or the like by a method of frame plating. In the same step mentioned above, individual ends of leads
56
a
1
and
56
b
1
are connected to central edges of coils Ca and Cb through contact holes (not shown), and upper connecting leads
57
a
and
57
a
are formed so as to pass over coils Ca and Cb. At the other ends of leads
56
a
1
to
56
a
4
, and
56
b
1
to
56
b
4
, bumps (not shown) are formed as connecting members with bonding pads
55
a
1
to
55
a
4
, and
55
a
1
to
55
b
4
, which are formed later so as to exceed heights of the upper core layers (not shown).
Next, protective layers (not shown) composed of alumina or the like are formed by sputtering so as to cover the upper layers of the upper core layers (not shown), leads
56
a
1
to
56
a
4
, and leads
56
b
1
to
56
b
4
. The protective layers are polished until parts of the bumps (not shown) thereunder are exposed, and then, gold bonding pads
55
a
1
to
55
a
4
, and
55
a
1
to
55
b
4
, are formed on the exposed bumps (not shown) by plating to complete sliders
53
a
and
53
b
. Sliders
53
a
and
53
b
are mounted at a supporting member
52
(not shown), then bonding pads
55
a
1
to
55
a
4
, and
55
a
1
to
55
b
4
, are connected through fine gold wires (not shown) or the like to flexible printed circuit boards (not shown) which are to be connected to processing circuits; thus, the magnetic head H can be obtained.
In order to write data efficiently on both sides of magnetic disk
51
, the magnetic head H is provided with two kinds of sliders
53
a
and
53
b
as shown in
FIG. 6
, in which two head elements
54
a
and
54
b
facing each other are located at positions equivalent to each other. Generally, a “mirrored pattern” is employed for sliders
53
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Nguyen Hoa T.
Watko Julie Anne
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