Etching a substrate: processes – Gas phase etching of substrate – Etching a multiple layered substrate where the etching...
Reexamination Certificate
1999-12-09
2002-04-09
Gulakowski, Randy (Department: 1746)
Etching a substrate: processes
Gas phase etching of substrate
Etching a multiple layered substrate where the etching...
C216S022000, C216S041000, C216S042000, C216S049000, C216S051000, C216S062000, C360S110000, C360S131000, C430S313000, C430S319000, C204S192100, C204S192150, C204S192200, C029S603070, C029S603180
Reexamination Certificate
active
06368519
ABSTRACT:
RELATED APPLICATION DATA
The present application claims priority to Japanese Application No. P10-353341 filed Dec. 11, 1998 and Japanese Application No. P11-070792 filed Mar. 16, 1999, which applications are incorporated herein by reference to the extent permitted by law.
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to an etching method and a method of manufacturing a magnetic head, and more specifically, to a method of manufacturing a magnetic head in which a magnetic gap is formed between non-magnetic materials provided on opposed surfaces of a pair of yoke cores which are formed to be opposed to each other on a substrate.
2. Background Art
In recent years, video tape recorders, audio tape recorders, computer data storage systems, and the like are known as magnetic recording/reproducing apparatuses which use a magnetic tape as a recording medium. As for the magnetic recording medium, there is a demand for increasing the recording density to enhance its capacity and to attain a high data transfer rate.
However, if the magnetic recording medium is improved to have a high recording density in a magnetic recording system, the magnetized information from the magnetic recording medium is so weakened that reproduced signals are difficult to detect for a conventional inductive type magnetic head using electromagnetic induction.
Hence, in bard discs or the like, a magnetic resistance effect type magnetic bead (which will be hereinafter referred to as an MR head) using a magnetic resistance effect element (which will be hereinafter referred to an MR element) made of a soft magnetic film such as NiFe alloy or the like has been used for reproduction of signals.
However, in case where the MR head is set in a helical scan tape system in which the magnetic head is mounted on a rotation drum and recording/reproducing is carried out while rotating the magnetic head, the MR element must be slid on a magnetic tape at a high speed, leading to a problem that the MR element is worn out. Once the MR element is worn out, serious problems are caused, e.g., the output and the bias amount changes, the operation stability is lowered, the resistance value changes, or so.
Therefore, a proposal has been made for a MR head of a yoke type in which an MR element is provided in the head and magnetic flux from a magnetic recording medium is guided to the MR element by a yoke core to reproduce signals. In this yoke type MR head, a pair of yoke cores made of a soft magnetic film are formed so as to be opposed to each other with a non-magnetic film inserted therebetween, on a substrate. The portions of the magnetic film provided at the opposed regions construct a magnetic gap.
In case where the magnetic gap is formed substantially in parallel with the surface of the substrate where a film is formed in the yoke type MR head as described above, the efficiency is degraded if the track width is narrowed as the recording density is increased to be high. Therefore, it is necessary that the magnetic gap is formed to be substantially vertical to the surface of the substrate where the film is formed.
FIGS. 58
to
66
show a first conventional method of forming a gap film. Note that
FIGS. 58
to
64
and
66
are views showing the forming method of the magnetic gap film in form of cross-sectional views cut along the line Y
1
-Y
2
in FIG.
65
.
At first, as shown in
FIG. 58
, a Cr film
31
and a SiO2 film
32
are formed in this order on a substrate
30
. Next, as shown in
FIG. 59
, a resist
33
is applied onto the SiO2 film
32
and is patterned into a predetermined shape. Specifically, a mask pattern is formed in which the resist
33
remains only one of parts of the substrate
30
divided along the portions where the magnetic gap is formed. Further, as shown in
FIG. 60
, etching is carried out with the mask pattern used as a mask, and the portions of the SiO2 film
32
which is exposed from the mask is removed.
Next, as shown in
FIG. 61
, a gap film
34
is formed entirely on the substrate
30
and the resist
33
, with the resist
33
remaining. Next, as shown in
FIG. 62
, the resist
33
is peeled together with the gap film
34
formed on the resist. Further, as shown in
FIG. 63
, the remaining SiO2 film
32
is removed by reactive etching. At this time, the gap film
34
formed on the substrate is removed except for the portion thereof which forms finally a magnetic gap.
Further, as shown in
FIG. 64
, a magnetic film
35
which forms part of a yoke core is formed on the entire surface, and the surface is polished, thereby forming the gap film
34
to be substantially vertical to the film forming surface of the substrate
30
. Further, yoke cores are patterned as indicated by a broken line in FIG.
65
.
Also,
FIGS. 67
to
76
show a second conventional method of forming a gap film.
At first, as shown in
FIG. 67
, a first magnetic film
41
is formed on the entire surface on a substrate
40
. Next, as shown in
FIGS. 68 and 69
, a resist
42
is applied onto the first magnetic film
41
and is patterned into a predetermined shape. Specifically, the mask pattern should be such that the resist
42
remains on the portion which forms one of a pair of yoke cores. Further, as shown in
FIG. 70
, etching is carried out with the mask pattern used as a mask, to remove the first magnetic film
41
exposed from the mask. At last, the resist
42
is removed so that one yoke core is formed as shown in
FIGS. 71 and 72
.
Next, as shown in
FIG. 73
, a gap film
44
is formed on the entire surface, and further, a second magnetic film
45
is formed on the gap film
44
. Further, the surface of the second magnetic film
45
is polished so that a pair of yoke cores are formed as shown in
FIGS. 75 and 76
and part of the gap film
44
is formed to be substantially vertical to the film forming surface of the substrate
40
. Further, as indicated by broken lines in
FIG. 75
, patterning forms the yoke cores.
In the conventional methods as described above, since yoke cores are formed one after another, the manufacturing steps are complicated. Also, in the second forming method, a difference in thickness appears between the yoke cores and causes a drawback that the off-track characteristic is deteriorated.
SUMMARY OF THE INVENTION
The present invention has been proposed in view of the actual situation of conventional techniques as described above, and has an object of providing an etching method and a method of manufacturing a magnetic head which are capable of forming a magnetic gap substantially vertical to the film forming surface of a substrate by a simple method with high accuracy.
According to the present invention, there is provided a method for manufacturing a magnetic head comprising a substrate and a pair of yoke cores formed on the substrate, provided so as to oppose each other, with a non-magnetic material provided between the pair of yoke cores thereby to form a magnetic gap, the method comprising: a non-magnetic film forming step of forming a non magnetic film made of the non-magnetic material on the substrate; a high selectivity film forming step of forming a high selectivity film made of a material which has a higher selectivity ratio with respect to reactive ion etching than the non-magnetic material, on the non-magnetic film formed in the non-magnetic film forming step; a patterning step of patterning the high-selectivity film formed in the high-selectivity film forming step, into a predetermined shape; and an etching step of etching the non-magnetic film by reactive ion etching, using the high selectivity film patterned into the predetermined shape as a mask.
In the method according to the present invention as described above, the non-magnetic film is etched by reactive ion etching with the patterned high selectivity film used as a mask. Therefore, the non-magnetic film which forms a magnetic gap can be formed with ease. Also, in the method of manufacturing a magnetic head, a fine magnetic gap can be formed with excellent accuracy since a high selectivity film made of a mat
Katakura Toru
Miyauchi Teiichi
Takanashi Yuko
Gulakowski Randy
Kornakov M.
Sonnenschein Nath & Rosenthal
Sony Corporation
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