JPH02294914A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To attain track width control with high accuracy by enlarging the angle of a taper in a part near a gap surface, which appears on the medium sliding surface of a through hole, rather than the angle of the taper in the direction of a magnetic path orthogonal to the medium sliding surface of the through hole. CONSTITUTION:An upper magnetic core 6 is joined through a gap material 3 to a lower core 2 in the part of a through hole 10 in front side and a magnetic gap is formed. In the part of a through hole in rear side, the upper core 6 is connected to the lower core 2 and thus, an interstage magnetic path is composed of the lower core 2 and upper core 6. For the through hole 10 in the front side of a coil insulating film 5, a taper angle beta on both side surfaces to appear on the sliding surface is made larger than a taper angle alpha in the direction of the magnetic path, namely, formed to be sharp and prepared so that a position can be matched with the lower core 2. It is preferable to set the taper angle alpha to the degree of 30-50 deg. and to set the taper angle beta to be sharp as much as possible more than 40 deg.. Thus, while maintaining the accuracy of track width, the leak of a magnetic flux is reduced in the taper part of the through hole 10 and performance degradation such as adjacent track disturbance, etc., is improved.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a thin film magnetic recording and reproducing device used in a type of magnetic recording and reproducing device that runs in relative contact with a magnetic recording medium of a video tape recorder (V'I''R)'J. Regarding head.

[Conventional technology]

In a type of magnetic recording/reproducing device, such as a VTR, in which a magnetic recording medium and a magnetic head run in relative contact with each other,
There is a problem of ensuring the wear life of the magnetic head, and in order to apply the thin film magnetic head to this type of magnetic recording/reproducing device, it is necessary to fabricate one with a large gap depth. To achieve this, in order to guide the magnetic flux to the tip of the gap, the core thickness must be increased to prevent the magnetic core in the middle from becoming saturated.
In order to achieve a gap depth of 10 to 15 μm, which is necessary to ensure a long running life, a magnetic core thickness of approximately 20 μm is required.

However, it is not easy to process such a thick magnetic piece with high precision. By the way, h is that ion etching is generally used as a method for processing the magnetic film in thin-film magnetic heads, but this method has the drawback of poor etching selectivity, and the photoresist 1~ used during processing is It requires a thick film, and there may be problems with accuracy. In particular, in the ion etching method, as is well known, there is a phenomenon in which the shoulders of resists 1~ are shaved diagonally during etching, so as the rack width becomes narrower, the shoulders of resists 1~, 3, 4 - The effective etching speed becomes faster, and the film thickness must be increased accordingly, making the situation even more difficult in terms of accuracy.

As described above, it is difficult to control the track width by etching a magnetic core with a film thickness of about 20 μm, which is necessary to ensure a predetermined gap depth, with high precision. Therefore, in order to deal with this point, for example, JP-A-11]61
As described in Japanese Patent No. 255514, there is a coil insulating film in which a through hole is formed by taper etching, and the width of the through hole is used to regulate the width of one rack.

Furthermore, as described in Japanese Patent Application Laid-Open No. 60-50711, there is a device in which a protrusion is provided on the front portion of the lower magnetic core, and the track width is regulated by the width of the protrusion.

[Problem to be solved by the invention]

However, in the track width control method using through holes of the former application mentioned above, no consideration is given to the taper angle of the through holes, resulting in decreased efficiency due to magnetic flux leakage at the tapered portions on both sides of the sliding surface, and There were problems such as rank interference. Further, in the latter method of providing a protrusion on the lower core of the prior application, consideration is not given to the shape of the lower core in parts other than the protrusion, and there is a problem that the part parallel to the gap surface becomes a pseudo gap. It is also possible to combine the techniques of the two prior applications described above, but even in that case, the problem of misalignment between the protrusion and the through hole is also added, and the same problem still occurs.

The present invention has been made in view of the above points, and its purpose is to eliminate problems such as magnetic flux leakage at the taper part of the through-hole that regulates the rack width and interference with adjacent racks, and to achieve high precision. An object of the present invention is to provide a thin film magnetic head capable of controlling track width.

[Means to solve the problem]

The above-mentioned object of the present invention is to laminate thin films such as a lower core, a gap material, a coil conductor, a coil insulating film, and a two-part core on a substrate, and a front side core provided on the coil insulating film on the gap forming surface. In a thin film magnetic head in which the rack width is regulated by the width of the through hole for bonding,
By making the taper angle of the through-hole near the gap surface, which appears in the medium sliding motion, larger (steeper) than the taper angle in the magnetic path direction perpendicular to the medium sliding surface of the through-hole. achieved.

Further, in the present invention, preferably, the lower core appearing on the medium sliding surface has a steep slope with a width approximately equal to the width of the rack in the vicinity of the gap surface, and as it moves away from the gap surface in the thickness direction, the lower core It has a shape with a wider width, and is configured to determine the 1-rack width by aligning and forming the lower core and the through hole.

[Effect]

By making the through-holes on both sides of the sliding surface steeper (the Taber angle is inverted), and by making the slope near the gap in the lower core steeper, the distance between the upper core and the lower core other than the magnetic gasop can be reduced. In addition, the spread of both the upper and lower cores can be suppressed to the necessary minimum, and magnetic flux leakage and interference with adjacent 1/racks can be improved.

〔Example〕

The present invention will be explained below with reference to the embodiments shown in FIGS. 1 to 9. FIG. 1 shows a thin film magnetic heel 1 according to the first embodiment of the present invention, in which (a) is a cross-sectional view along the magnetic path direction, and (b) is a cross-sectional view of the heel 1 and the heel 1 moving surface. FIG.

In Fig. 1, 1 is a non-magnetic substrate, 2 is a lower (magnetic) core formed in the groove of the non-magnetic substrate 1, and both sides of the front part are near the gap surface or steeply inclined from the gap surface to the core. The core width increases as it goes in the thickness direction, and the core is made so that there are no gaps or parallel parts on both sides of the core.

8 is a non-magnetic insulating material (lower core embedding material), which embeds the core 2 flush with -1. 4 is a coil conductor, 5 is a coil insulating film in which the coil conductor 4 is buried, and through holes 10 and 1 are formed on the front side (Gannop surface side) and rear side, respectively. 6 is the upper (magnetic) core, Freon 1
The through hole on the rear side is connected to the lower core 2 via the gap material 3, thereby forming a magnetic (operation) gap. and is connected to the lower core 2, whereby the lower core 2 and the upper core 6 form a closed magnetic path. Note that 7 is a protective film.

Through-hole 10 on the side of the coil insulating film 5 to the freon 1
is formed so that the taper angle β of both side surfaces appearing on the sliding surface is larger (steeper) than the taper angle α in the magnetic path direction, and is aligned with the lower core 2. It is preferable that the taper angle α is about 30 to 50 degrees, taking into account the core cross-sectional area and step coverage at the taper part, and the other taper angle β is 40' or more and as steep as possible. By purchasing in this way, it is possible to reduce magnetic flux leakage at the tapered portion of the through hole 10 while maintaining the 1-rack width accuracy, and improve performance deterioration such as interference with adjacent tracks. In addition,
Although FIG. 1(b) shows an example in which there is no positional deviation between the lower core 2 and the through hole 10, it goes without saying that the above-mentioned effects can be sufficiently obtained even when there is some positional deviation.

? FIG. 3 is a front view showing the sliding surface of the pad, and although the cross section in the magnetic path direction is not shown, it is equivalent to the first embodiment. In this embodiment, the through hole 10 on the front side of the coil insulation 1 model 5 has a tapered shape on both sides of the sliding body in two steps (taper angle β).
(2) The taper angle is β2), and the taper angle β1, which is close to the gap surface, is steep. As in this embodiment, shortening the portion of the steep taper angle β1 is advantageous for forming the magnetic film (upper core 6), and it is easier to increase the angle of the steep portion than in the first embodiment. The effect of improving the positional deviation of the through hole 10 is also large.

Next, a method for forming the through hole 10 in the coil insulating film 5 will be explained with reference to FIGS. 3 to 3G.

In general, in Taber etching using dry etching methods such as reactive ion etching and ion milling, the gentle slope of the edge of the resist 1 obtained by baking the boss 1 is transferred to some extent. At this time, the slope O of the resist 1 to edge changes depending on the relationship between the resist 1 film thickness t and the resist 1 width C of the photoresist pattern 9 shown in FIG. 3(a). ) The angle can be easily changed within a range of about 90 to 30 degrees, as shown in one example.

Therefore, using the above relationship, as shown in FIG. ,
By setting the distance 1 [t I, o between the edge of the front through hole 10 and the edge of the rear side through hole 11 to be shorter than The taper angle β on both sides of the moving surface can be made larger and steeper than the taper angle α in the magnetic path direction.

Further, there is also a method as shown in FIG. 5 as another method. When using a reactive gas as an etching method, a mask material with sufficiently high etching selectivity can be selected. For example, when the coil insulating film 5 is made of Si○2, Cr is hardly etched by reactive gases such as CF and CHF3. , Cu, etc., and insulating materials such as Steartie 1-, Forsterei 1-1, etc. A material having sufficiently high etching selectivity with respect to these reactive gases is used as the first mask material 12 as shown in FIG. A second mask material 13 made of photoresist 1 is placed and formed on the two sides where it is desired to have a steeper Taber angle, and dry etching is performed using a reactive gas as described above. This results in
The coil insulating film 5 in the area where the first mask material 12 is placed is steeply etched, and the coil fiber membrane 5 in the area where the second mask material 13 is placed is gently etched (Taber etching). ). Therefore, even with the direction a1 shown in FIG. 5, it is possible to make the Taber angle β on both sliding sides of the through hole 10 larger and steeper than the Taber angle α in the magnetic path direction, as in the first embodiment. I can do it.

Next, a method of forming the shape of the through hole 10 of the second embodiment (FIG. 2) will be explained with reference to FIG. 6.

After coating the entire surface of Ho 1 to Resist 1 and 13 again using the method shown in Figures 3 and 4 or Figure 5, as shown in Figure (b).
The entire surface is dry-etched for a predetermined period of time as shown in FIG. For removal, the tapered shape on both sides of the sliding surface is
A through hole 10 having a steep taper angle β1 and a gentle taper angle β2 connected thereto is obtained.

Next, a method for forming the lower core 2 having the above-mentioned front shape will be explained with reference to FIG.

First, as shown in FIG. 7(a), a groove 1a is formed in a predetermined portion of the non-magnetic substrate 1, and then, as shown in FIG. 7(b), a magnetic film 14 (lower core 2) is deposited to a predetermined thickness and then etched, and then, as shown in FIG. 3(c), the non-magnetic fiber material 8 is formed and flattened. Subsequently, as shown in FIG. 2D, predetermined portions of the magnetic film 14 are masked and etched to remove the eyebrows of the front portion (gap forming portion) of the magnetic film 14 and the non-magnetic substrate 1.
, the non-magnetic insulating material 8 is etched, and then the same figure (e) is etched.
As shown in FIG. 2, a non-magnetic insulating material 8 is formed again, and is planarized. As a result, as shown in FIG. 1(b), a lower core 2 is obtained which has a front portion which is steep near the gap and whose core width increases as the distance from the gap increases in the core thickness direction. In addition, 2 in the same figure (d) marked ``2''
In order to control the taper angle on both sides of the front part of the lower core 2 in the double etching process, it is only necessary to appropriately select the beam incidence angle of the ion etching. You can avoid creating such parts. Here, in the example shown in FIG. 7, the process of etching the magnetic film twice was explained, but in the example shown in FIG.
It goes without saying that the shape of the lower core at the end of the process shown in ) may also be used.

By the way, Freon + part of the core width of the upper core 6 is:
Since it is regulated by the width of the through hole 10, it is easy to adapt to narrower rack widths, but the method for forming the lower core 2 shown in FIG. , there are limits to j conversion. 8 and 9 each show a method of making the trunk width of the lower core 2 even narrower, and FIG. 8 is a plan view showing the concept of the manufacturing method;
FIGS. 9(a) to (1) are explanatory diagrams of each process shown in the cross section taken along the line B--B in FIG. 8.

In the method for creating the lower core 2 shown in FIGS. 8 and 9,
First, a non-magnetic substrate 1 with grooves 1a formed therein (FIG. 9(a))
A magnetic film 14 (lower core) is deposited and filled into the groove 1a and flattened (FIG. 1(b)), and then the magnetic film 14 is selectively covered with hole resists 1 to 13 (FIG. 1(b)). (c)). After performing the second etching in this state (etching is done on the part surrounded by the solid line in Fig. 8),
((d) in the same figure). By this, the magnetic film]4
One side defining the width of 1-1 is formed. Subsequently, a non-magnetic fiber material 8 is formed and flattened (FIG. 1(c)), and then photoresis 1-13 is performed again.
selectively covering the magnetic film 14 ((f) in the same figure),
After performing the second etching in this state (etching the area surrounded by the dotted line in Fig. 8),
3 (Giant I(g)). Thanks to your talent, magnetic 4
The raw film 4, that is, the external force side that defines the width of the I-lasock in the lower core 2, is formed, and then a non-magnetic insulating material 8 is formed and this is subjected to a -tlZ planarization process ( 1(e)).

The lower core 2 formed by such a manufacturing process has the etching process divided into two steps to finish the lower core 2 into the desired shape.
- It is easy to narrow the width of the rack because it has a fine width equivalent to the rack width and there is no need to increase the thickness of the resist 1.
- Rack width accuracy is also good.

〔Effect of the invention〕

As described above, according to the present invention, there is no problem such as reduced efficiency due to magnetic flux leakage at the through-hole taper portion that regulates the rack width or interference with adjacent racks, and there is no problem such as interference with adjacent racks.
It is possible to provide a thin film magnetic belly button 1 which allows rack width control, and its industrial value is great.

[Brief explanation of the drawing]

・ 15 ・ 16 ・ The drawings all relate to embodiments of the present invention, and FIG. ) is a front view showing the sliding surface of the same thin film magnetic head 1, FIG. 2 is a front view showing the sliding surface of the thin film magnetic head according to the second embodiment of the present invention, and FIG.・Explanatory diagram showing the cross section of resist 1-pattern, same figure (1
)) is a graph showing the relationship between the resist width Ω/resist l/film thickness t and the slope O of the resist edge, and Figure 4 is for forming the through hole of the first embodiment using the relationship in Figure 3. FIG. 5(.) is a plan view of the main part showing another method for forming the through hole of the first embodiment, and FIG. A in figure (a)
-A sectional view, FIG. 6 is a process explanatory diagram showing a method for forming the through hole of the second embodiment, and FIG. 7 is a process explanatory diagram showing one method for forming the lower core. FIG. 8 is a plan view of a main part showing the concept of another method for forming the lower core, and FIG. 9 is a process explanatory diagram shown in a cross section taken along line B-13 in FIG. 8. ■・Nonmagnetic substrate, 2. Lower core, 3.. Gap material, 4. Coil conductor, 5.. Coil insulation film, 6. Upper core, 7. Protective film, 8.
・Non-magnetic insulating material (lower core embedding material), 9. Hole 1 - pattern to resist 1, ]-〇. Front side through hole, Co-1... Rear side through hole, 12.. First mask material , 13...Second mask material (hole 1-resis 1~), 14
magnetic film. ＼＼＼＼＼＼＼＼＼＼＼＼＼＼＼＼＼＼＼＼／Fig.

Claims (1)

[Claims] 1. Thin films such as a lower core, a gap material, a coil conductor, a coil insulating film, and an upper core are laminated on a substrate, and the front side core bonding is provided on the coil insulating film on the gap forming surface. In a thin film magnetic head in which the track width is regulated by the width of the through hole, the taper angle of at least a portion near the gap surface appearing on the medium sliding surface of the through hole is perpendicular to the medium sliding surface of the through hole. A thin film magnetic head characterized by having a taper angle larger (steeper) than the taper angle in the direction of the magnetic path. 2. In claim 1, the taper of the through hole appearing on the medium sliding surface includes a steep taper angle portion near the gap surface and a relatively gentle taper angle portion continuous with the steep taper angle portion. A thin film magnetic head characterized by having: 3. In claim 1, the lower core appearing on the medium sliding surface has a steep slope with a width approximately equal to the track width in a portion near the gap surface, and the core width increases as the distance from the gap surface increases in the thickness direction. 1. A thin film magnetic head, characterized in that the lower core and the through hole are aligned and formed to determine the track width. 4. In claim 1, the width of one side of the coil insulating film in a cross section including the through hole formed in the coil insulating film on the gap forming surface and parallel to the medium sliding surface is on the gap forming surface. A thin film magnetic head characterized in that the distance is shorter than the distance from the edge of the through hole for connecting the front side core to the edge of the through hole for connecting the rear side core. 5. In claim 1, the through hole formed in the coil insulating film on the gap forming surface is perpendicular to the medium sliding surface and regulates the track width.
A mask material having a sufficient etching selectivity with respect to the coil insulating film provided for positioning the side, and a mask material made of photoresist provided for positioning the other side of the through hole parallel to the medium sliding surface. In the attached state,
A thin film magnetic head characterized in that it is manufactured by etching a coil insulating film by dry etching using a reactive gas. 6. The thin film magnetic material according to claim 1, wherein the front portion of the lower core has a core width that is at least approximately equivalent to the track width, and both sides of the core portion are formed by separate etching processes. head.