Dynamic magnetic information storage or retrieval – Head – Core
Reexamination Certificate
1999-12-06
2001-11-20
Klimowicz, William (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Core
C360S123090
Reexamination Certificate
active
06320726
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thin film magnetic head having at least an inductive-type magnetic transducer for writing, a method of manufacturing the same, and a method of forming a thin film coil.
2. Description of the Related Art
In recent years, improvement in performance of thin film magnetic heads has been sought in accordance with improvement in surface recording density of a hard disk drive. As a thin film magnetic head, a composite thin film magnetic head in which a recording head having an inductive-type magnetic transducer for writing and a reproducing head having a magnetoresistive element (hereinbelow, referred to as MR) for reading-out are stacked is widely used. MR elements include an AMR using an anisotropic magnetoresistive effect (hereinbelow, referred to as AMR) and a GMR element using giant magnetoresistive effect (hereinbelow, described as GMR). A reproducing head using the AMR element is called an AMR head or simply an MR head. A reproducing head using the GMR element is called a GMR head. The AMR head is used as a reproducing head whose surface recording density is higher than 1 gigabit per square inch. The GMR head is used as a reproducing head whose surface recording density is higher than 3 gigabits per square inch.
As methods of improving the performance of a reproducing head, there are a method of changing the material of the MR film to a material having excellent magnetoresistivity of the AMR film, GMR film, or the like, and a method of making the pattern width of the MR film, especially, the MR height proper, and the like. The MR height is the length (height) from the end part on the air bearing surface side of the MR element to the end part on the opposite side and is controlled by the polishing amount at the time of processing the air bearing surface. The air bearing surface is a surface of a thin film magnetic head, which faces a magnetic recording medium, and is also called a track surface.
On the other hand, in accordance with the improvement in performance of a reproducing head, the improvement in performance of a recording head is also required. One of the factors of determining the performance of a recording head is the throat height (TH). The throat height is the length (height) of a magnetic pole part extending from the air bearing surface to the edge of an insulating layer which electrically isolates a thin film coil for generating a magnetic flux. In order to improve the performance of a recording head, reduction in the throat height is desired. The throat height is also controlled by the polishing amount at the time of processing the air bearing surface.
Further, in order to improve the performance of the recording head, it is proposed to shorten the length (hereinbelow, called a magnetic path length) of the part sandwiching the thin film coil of a bottom pole and a top pole formed while sandwiching a write gap.
With reference to
FIGS. 16A and 16B
through
FIG. 21
, as an example of a method of manufacturing a conventional thin film magnetic head, an example of a method of manufacturing a composite thin film magnetic head will be described.
FIGS. 16A through 20A
are sections each of which is perpendicular to the air bearing surface in a main manufacturing process.
FIGS. 16B through 20B
are sections each of which is parallel to the air bearing surface in a main manufacturing process.
FIG. 21
illustrates a plane structure of a completed composite thin film magnetic head.
First, as shown in
FIGS. 16A and 16B
, an insulating layer
102
made of, for example, alumina (aluminium oxide, Al
2
O
3
) is formed in a thickness of about 5 to 10 &mgr;m on a substrate
101
made of, for example, altic (Al
2
O
3
.TiC). Subsequently, a bottom shield layer
103
for a reproducing head made of, for example, permalloy (NiFe) is formed on the insulating layer
102
. For example, alumina is then deposited in a thickness of 100 to 200 nm on the bottom shield layer
103
to form a shield gap film
104
. An MR film
105
for constructing an MR element for reproducing is formed in a thickness of tens of nanometers on the shield gap film
104
and is formed in a desired shape by high-precision photolithography. Then a lead terminal layer
106
for the MR film
105
is formed by lift-off method. A shield gap film
107
is formed on the shield gap film
104
, the MR film
105
and the lead terminal layer
106
, and the MR film
105
and the lead terminal layer
106
are embedded in the shield gap films
104
and
107
. An top shield-cum-bottom pole (hereinbelow, referred to as bottom pole)
108
with 3 &mgr;m thick made of a magnetic material such as permalloy (NiFe) used for both the reproducing head and the recording head is formed on the shield gap film
107
.
On the bottom pole
108
, a write gap layer
109
with 200 nm thick made of as an insulating film such as an alumina film is formed. Further, the write gap layer
109
is patterned by photolithography and an opening
109
a
for connecting the top pole and the bottom pole is formed. Subsequently, a pole tip
110
is formed by using a magnetic material such as permalloy (NiFe) or iron nitride (FeN) by plating and a connecting part pattern
110
a
for connecting the top pole and the bottom pole is formed. By the connecting part pattern
110
a,
the bottom pole
108
and a top pole layer
116
which will be described hereinlater are connected and formation of a through hole after a CMP (Chemical Mechanical Polishing) process which will be described hereinlater is facilitated.
Subsequently, as shown in
FIGS. 17A and 17B
, the pole tip
110
is used as a mask and the write gap layer
109
and the bottom pole
108
are etched about 0.3 to 0.5 &mgr;m by ion milling. Etching is performed to the bottom pole
108
and a trim structure is obtained, thereby preventing the effective write track width from being expanded (that is, the expansion of a magnetic flux in the bottom pole is suppressed when data is being written). Subsequently, an insulating layer
111
made of, for example, alumina with a thickness of about 3 &mgr;m is formed on the whole surface and then the whole surface is planarized by CMP.
As shown in
FIGS. 18A and 18B
, a thin film coil
112
as the first layer for an inductive recording head made of, for example, copper (Cu) is selectively formed on the insulating layer
111
by plating or the like. Simultaneously, a pattern
112
a
for connecting coils is formed integrally with the thin film coil
112
on the insulating layer
111
rearward of the connecting part pattern
110
a.
A photoresist film
113
is formed in a predetermined pattern by high-precision photolithography so as to cover the insulating layer
111
, thin film coil
112
and coil connecting pattern
112
a.
The photoresist film
113
is patterned so as to form openings
113
a
and
113
b
for exposing the top surface of each of the connecting part pattern
110
a
and the coil connecting pattern
112
a.
Subsequently, heat treatment is performed at a predetermined temperature for planarizing the photoresist film
113
and for insulating between the turns of the thin film coil
112
.
As shown in
FIGS. 19A and 19B
, a thin film coil
114
as the second layer is selectively formed on the photoresist film
113
. Simultaneously, a pattern
114
a
for connecting coils to be electrically connected to the coil connecting pattern
112
a
is formed integrally with the thin film coil
114
on the opening
113
b
of the photoresist film
113
. Subsequently, a photoresist film
115
is formed so as to cover the thin film coil
114
as the second layer and the coil connecting pattern
114
a.
Further, heat treatment is performed at a predetermined temperature for planarizing the photoresist film
115
and for insulating between the turns of the thin film coil
114
.
As shown in
FIGS. 20A and 20B
, an top yoke-cum-top pole layer (hereinbelow, referred to as top pole layer)
116
made of a magnetic material such as permalloy for the recording head is selectively formed on the po
Klimowicz William
Oliff & Berridg,e PLC
TDK Corporation
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