Dynamic magnetic information storage or retrieval – Head – Magnetoresistive reproducing head
Reexamination Certificate
2000-12-20
2002-11-05
Heinz, A. J. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Magnetoresistive reproducing head
C360S234700, C360S317000
Reexamination Certificate
active
06477019
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention concerns methods of manufacture of magnetic head devices in which a thin film magnetic head element is formed on one face of a slider.
2. Background Information
As has been disclosed in Laid-Open Patent Application Hei8-30944 and Laid-Open Patent Application Hei10-172125, magnetic head devices of the prior art which are mounted in hard disk devices are fabricated by forming numerous thin film magnetic head elements consisting of multiple component layers in a lattice array on a nearly disc-shaped wafer surface of, for example, Al
2
O
3
—TiC, cutting said wafer into individual head blocks, and forming into a slider shape by etching the surface opposing the magnetic recording media consisting of a cut surface.
The aforementioned thin film magnetic head element is formed by vertical layering, using vacuum thin film formation means, of a magnetoresistance effect head (MR head) for reproduction and an inductive head for recording.
Magnetoresistance effect elements, in general, have as principal components a lower magnetic shield layer, lower magnetic gap layer consisting of alumina (Al
2
O
3
), magnetoresistance effect element layer (MR element), electrode layer, upper magnetic gap layer consisting of alumina, and upper magnetic shield layer. Inductive heads have as principal components a lower magnetic pole layer, gap layer consisting of alumina, coil layer, insulating layer, and upper magnetic pole layer. These component head layers are formed by successive layering using vacuum thin film formation techniques.
The magnetic gap layers of each head are exposed to the surface of the head block opposing the magnetic recording media, in order to perform writing to or reading from the magnetic recording media.
With the larger capacities and smaller sizes of hard disk devices in recent years, the magnetic disks which are the magnetic recording media are required to have still higher track densities. In consequence of their characteristics, the MR heads used for reproduction are able to accommodate higher densities than are the inductive heads used for recording; but the following problems arise when raising the track densities of inductive heads.
As shown in
FIG. 6
, inductive heads of the prior art
41
have a wide lower magnetic pole layer
42
, a magnetic gap layer
43
formed by layering on top of said layer
42
, and a narrow upper magnetic pole layer
44
formed by layering on top of said gap layer
43
; the effective track width is determined by the width of said upper magnetic pole layer
44
. Hence in order to raise the track density, the upper magnetic pole layer
44
must be formed with a more narrow width, and a magnetic field must be generated in the narrow area between said upper magnetic pole layer
44
and lower magnetic pole layer
42
.
However, as track widths become extremely small, the effect of the lateral leakage magnetic field A from the upper magnetic pole layer
44
becomes too large to be neglected. Hence in order to reduce the leakage magnetic field A as much as possible while maintaining the required magnetic field strength, it is desirable that the lower magnetic pole layer
42
be trimmed as in
FIG. 7C
, and a trimmed part
45
(protrusion) of the same width as the upper magnetic pole layer
44
be formed, in a construction in which said trimmed part
45
effectively acts as the lower magnetic pole.
After forming the upper magnetic pole layer
44
as shown in
FIG. 7A
, this trimmed part
45
is formed by patterning the gap layer
43
and lower magnetic pole layer
42
using the upper magnetic pole layer
44
as a mask, as shown in
FIGS. 7B and 7C
.
In the past, alumina (Al
2
O
3
) has been widely used as the component material of the gap layer
43
; but when ion milling is used in patterning to trim the alumina of the gap layer
43
and the lower magnetic pole layer
42
, because of the low milling rate of alumina, after milling the shape is tapered, and the upper and lower magnetic poles
44
,
45
, facing each other across the gap
43
, are not of the same width.
On the other hand, in order to make the widths of the upper and lower magnetic poles
44
,
45
identical, it has been proposed that reactive ion etching or some other reactive plasma method be used to selectively pattern the gap layer
43
of alumina vertically, after which ion milling is used to pattern the lower magnetic pole layer
42
. Because in this method two types of equipment are used—equipment for performing reactive ion etching, and equipment for ion milling—equipment costs are increased.
SUMMARY OF THE INVENTION
A method of manufacturing a magnetic head device is disclosed. In one embodiment, the method includes forming, on a surface of a wafer and in a lattice array, numerous thin film magnetic head elements including of a plurality of component layers including a magnetic gap layer including a nonmagnetic material. The wafer is cut into individual head blocks. The surface included in a cut surface of said head block to oppose a magnetic recording media is formed by etching into a slider shape. The component material of the magnetic gap layer existing in a region in which the etching is to be performed is removed in advance.
REFERENCES:
patent: RE35800 (1998-05-01), Chapin
patent: 6188544 (2001-02-01), Mino
patent: 6346338 (2002-02-01), Watanabe
Matono Naoto
Miyazaki Tomihito
Shiromoto Tatsuya
Burgess & Bereznak LLP
Heinz A. J.
Read-Rite SMI Corporation
LandOfFree
Thin film magnetic head including nonmagnetic and magnetic... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thin film magnetic head including nonmagnetic and magnetic..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thin film magnetic head including nonmagnetic and magnetic... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2951179