Dynamic magnetic information storage or retrieval – Record transport with head stationary during transducing – Drum record
Reexamination Certificate
1999-03-19
2001-04-03
Kelly, C. H. (Department: 1756)
Dynamic magnetic information storage or retrieval
Record transport with head stationary during transducing
Drum record
C430S320000, C216S047000
Reexamination Certificate
active
06212033
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a slider used for a flying magnetic head or the like and a method for manufacturing the same.
2. Description of the Related Art
A flying magnetic head used in a magnetic disc apparatus or the like is configured by forming a thin film magnetic head element at the rear end of a slider. In general, a slider includes rail portions whose surfaces act as flying surfaces (air bearing surfaces) and includes a taper or step portion in an air inflow portion (in the vicinity of the end at the air inflow side) such that the rail portions slightly fly above the surface of a magnetic recording medium such as a magnetic disc by a stream of air flowing in through the tapered or stepped surface.
In general, a slider having a taper portion at an air inflow portion is formed into a predetermined configuration through a mechanical process such as lapping. A slider having a step portion at an air inflow portion thereof (hereinafter referred to as “a step leading type slider”) is formed into a predetermined configuration through an etching process utilizing photolithography, for example, as disclosed in Japanese examined patent publication (KOKOKU) No. H5-8488.
A step leading type slider can be accurately formed even into a complicated configuration because it is manufactured using photolithography instead of a mechanical process as described above. This is advantageous in that it facilitates control over flying characteristics and in that processing cost can be reduced.
Recently, a need has arisen for a reduction in the flying amount of a slider for an improved recording density. It is also desired to improve the stability of the flying of a slider in order to achieve access at a higher speed. Negative pressure sliders have been put in use to satisfy such needs. In general, a negative pressure slider is formed with a negative pressure generating portion having a concave configuration to generate a negative pressure between two rail portions. Such a negative pressure slider has a microscopic configuration on a surface thereof facing a recording medium and, especially, the height of the rail portions is significantly smaller than those in conventional sliders.
Such a negative pressure slider of the above-described step leading type, the depths of the step portion and negative pressure generating portion relative to the flying surfaces are different from each other.
A description will now be made with reference to FIG.
12
through
FIG. 21
on an example of a method for manufacturing a step leading type negative pressure slider of the related art and on problems with the related-art methods for manufacturing sliders.
It is assumed here that a slider
211
having a configuration as shown in the plan view of
FIG. 13
is manufactured. The slider
211
includes two rail portions
212
whose surfaces serve as flying surfaces
212
a,
a step portion
213
formed at an air inflow portion and a negative pressure generating portion
214
formed to extend from the central portion to the air outflow side thereof. For example, the depth of the step portion
213
relative to the flying surfaces
212
a
is 1 &mgr;m, and the depth of the negative pressure generating portion
214
relative to the flying surfaces
212
a
is 3 &mgr;m. The slider
211
includes a thin film magnetic head element
215
provided in a position close to the end at the air outflow side of one of the rail portions
212
.
According to the manufacturing method in the related art, the slider bar including a plurality of thin film magnetic head elements arranged in a row is first secured to a jig after lapping of the surfaces thereof to serve as flying surfaces is completed.
The subsequent steps will be described according to the flow chart shown in FIG.
12
. First, as shown in
FIGS. 14 and 15
, a photoresist mask
231
is formed using photolithography on regions
222
of the slider bar
210
to become the rail portions
212
(step S
201
).
FIG. 14
is a plan view showing a region of the slider bar
210
which is to become one slider, and
FIG. 15
is an enlarged sectional view taken along the line
15
—
15
in FIG.
14
.
Next, for example, ion milling is performed to etch a region
223
to become the step portion
213
and a region
224
to become the negative pressure generating portion
214
by, for example, 1 &mgr;m using the photoresist mask
231
(step S
202
).
Next, as shown in
FIGS. 16 and 17
, the photoresist mask
231
is removed (step S
203
).
FIG. 16
is a plan view similar to
FIG. 14
, and
FIG. 17
is a sectional view similar to FIG.
15
.
Next, as shown in
FIGS. 18 and 19
, a new photoresist mask
232
is formed on the regions
222
to become the rail portions
212
and the region
223
to become the step portion
213
using photolithography (step S
204
).
FIG. 18
is a plan view similar to
FIG. 14
, and
FIG. 19
is a sectional view similar to FIG.
15
. Next, for example, ion milling is performed to etch the region
224
to become the negative pressure generating portion
214
by, for example, 2 &mgr;m using the photoresist mask
232
(step S
205
).
Next, the photoresist mask
232
is removed as shown in
FIGS. 20 and 21
(step S
206
). The slider
211
is thus formed.
FIG. 20
is a plan view similar to
FIG. 14
, and
FIG. 21
is a sectional view similar to FIG.
15
.
According to the method for manufacturing a slider of the related art as mentioned above, to form the step portion
213
and negative pressure generating portion
214
which are different in depth from each other relative to the flying surface
212
a,
the series of steps of forming photoresist masks, etching and removing the photoresist mask is repeated twice. Therefore, when the second photoresist mask
232
is formed, the photoresist mask
232
must be positioned accurately especially at the boundaries between the regions
222
to become the rail portions
212
and the region
224
to become the negative pressure generating portion
214
.
In practice, however, when the second photoresist mask
232
is formed, it is subjected to a positional shift, for example, in the range from 0.3 to 0.5 &mgr;m attributable to low positioning accuracy of an exposure mask for photolithography and the like as shown in
FIGS. 18 and 19
.
As a result, steps
241
are formed on side surfaces connecting the flying surfaces
212
a
and negative pressure generating portion
214
as shown in
FIGS. 20 and 21
. When such steps
241
is formed, the flying characteristics of the slider
211
will be different from design values, which can cause problems such as a horizontal shift of the slider in use in some cases.
SUMMARY OF THE INVENTION
The present invention has been conceived taking the above-described problems into consideration, and it is an object of the invention to provide a method for manufacturing a slider which makes it possible to accurately manufacture a slider having a first surface to serve as a flying surface (e.g., the flying surface
212
a
in FIG.
21
), a second surface formed in a position at a predetermined first depth (e.g., D
1
in
FIG. 21
) relative to the first surface and a third surface (e.g., the surface of the negative pressure generating portion
214
in
FIG. 21
) formed in a position at a predetermined second depth (e.g., D
2
in
FIG. 21
) relative to the first surface greater than the first depth.
It is another object of the invention to provide a slider having a first surface to serve as a flying surface, a second surface formed in a position at a predetermined first depth relative to the first surface and a third surface formed in a position at a predetermined second depth relative to the first surface greater than the first depth, wherein designed flying characteristics can be achieved.
A method of manufacturing a slider according to the present invention is a method for manufacturing a slider having a first surface to serve as a flying surface, a second surface formed in a position at a predetermined first depth relative to the first surface and a thi
Kelly C. H.
Oliff & Berridg,e PLC
TDK Corporation
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