Note: Descriptions are shown in the official language in which they were submitted.
r~ ~ PCT/EP91/00713
Proces~ for producing a ~hin-film magnetic tape head
There is no promising approach known for manufacturing a
true thin-film magnetic tape head with azimuth. ~nown
metal-in-gap (e.g. Sony TSS, etc.) or lamelIar sendu~t-
amorphous head~ are manufactured in blocks (non-planar) and
the formation of ths air gap is carried out via through the
putting together of two half-blocks. Thin-film blocks like,
for example, the IMB Spiral ~ard Disk head, is, owing to the -
small gap height, not suitàble for systems with tape-head
contact as is required in magnetic tape devices.
A gap inclination (azimuth) can only be generated
I through mechanically machining the backing material
j (substrate).
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Apart from that, such a type of magnetic tape head
cannot be considered for analog systems (long tape
' wavelengths and secondary gap effects). Systems with
;i azimuth are necessary for track-on-track writing without
- lawns (separating areas bet~en the recording tracks~.
¦ It is the object of the invention to manufacture a
magnetic tape head in ~hin-film technology without combining
the ~wo half-blocks.
~ his task is solved according to the invention by the
features o~ the first patent claim~ Advantageous further
developments result from the subclaims.
,
: The invention-type process for manufacturing heads
de~cribed in the following combine~ the advantages of planar
thin-film technology and gap production with the magnetic
and mechanical advan~ages of heads manufactured
.
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2 0 ~ O ~ 7 9 PCT/EPgl/00713
conventionally. In the following one possible embodLment
example is more closely explained by means of drawings. In
khe drawings are illustrated:
Fig. 1 a section from a wafer according to the
first and second procedure step,
Fig. 2 ~he wafer section following a third
procedure ~tep,
Fig. 3 the wafer section following a fourth
procedure step,
Fig. 4 the wafer section following a fi~th
procedure step,
Fig. 5 the wafer section following a si~th and
seventh procedure step,
Fig. 6 the wafer section following a eighth and
ninth procedure step, cmd
Fig. 7 the wafer section following a tenth through
fourteenth procedure step.
In a first procedure step for manufacturing a thin-film
mag~etic tape head, a substrate 1 (wafer) is provided with
coating 2 which is resistant to a caustic medium for the
substrate 1. The coating 2 is deposited by means of vapor-
deposition, sputtering or by an oxidation process.
In a ~econd named step, a window 3 i~ etched into the
coating 2 by means of a photographic or photolithographic
technique (Fig. lj.
I
¦ In the third step a cavity 4 is etched into the
I substrate 1 through the windvw 3 ~Fig. 2~.
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Following thisj a soft magnetic material 5, for e~ample,
Sendust, is deposited onto the substrate. This is
preferably carried out through sputtering of the window,
whereby in the cavity 4, a prismoid 6 formed as a part
projecting upwards ensues (hour-glass effect) (FigO 3).
After this, the coating 2 and the soft magnetic material
5 deposited on this are removed, for example, by stripping
(Fig. 4).
In a sixkh procedure step the substrate 1 is etched away
so far from both sides of the prismoid 6 until the prismoid
projects out of the substrate surface.
In a seventh procedure step the substrate 1 is provided
with a coating which serves as a gap layer 7. ~his is
carried out by means of sputtering or vapor~deposition. The
gap layer (gap spacer) later fonms the non-magnetic air gap
(Fig. 5).
By using as~mmetric etching, for example, ~y inclining
the wafer or the etching device, the gap coating is dione
etched one-sidedly, i.e. sputtered parts are not etched.
Thereby, the gap coating only remains on one side of the
pri~moid.
Following this, a further layer 8 is deposited on to the
sl~bstrate 1 and said layer also consists of a soft magnetic
material such as Sendust, for example (Fig. 6).
A~ter this, the ~arious parts of the magnetic tape head,
for example, pole shoes, winding space, etc~, are shaped via
a template by etching in the layer 8.
.
~ hen the substrate 1 is polished, whereby the prismoid
apex (gusset ape~) is remo~ed.
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~ - 4 -2 0 ~ ~ ~ 7 9 PCT/EP91/00713
After this, the head windings are manufactured in thin-
film technology (not illustrated in the figures) which form
the head legs of ~he thin-film magnetic tape head.
The return path of the head windings is closed via a
further soft magnetic layer.
After this, the substrate or the wafer is provided with
a further thick layer 9, for example, a metal oxide such as
AL203, and thereby protected (Fig. 7).
Finally, the wafer is divided, ground and polished, and
can then be passed on for further processing.
The process described above has the particular advantage
that there are no limitations regarding the material and the
track width of the tape for the magnetic tape head. Apart
from that, a lamina~ion is possible, whereby eddy current
osses can be prevented. In addition, only one polishing
j procedure is required. Further, by using the process, pure
silicon scanners can be manu~actured because always two
magnetic tape heads are so arranged on the head drum that
; they are located opposite a certain azimuth in pairs.
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