JPH0264909A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To increase the thickness of a coil and to suppress the increase in the resistance value of the coil by the increased number of windings by forming the coil of a laminate formed with the films of a plating substrate, Cu plating layer and carbon layer in this order. CONSTITUTION:The ion etching rate of carbon in a gaseous Ar atmosphere is extremely low. Since the carbon layer 5 is laminated on the Cu plating layer 3, the carbon layer 5 of the low ion etching rate protects the surface of the Cu plating layer 3 even if the front surface of the coil is ion etched over a long period of time at the time of ion etching in the plating substrate removing stage during the coil forming process; therefore, the decrease of the coil voltage does not arise. The increase in the resistance value of the coil by the increased thickness of the coil and the increased number of the windings is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inductive thin film magnetic head used in magnetic disk devices, magnetic tape devices, etc., and particularly relates to a coil fabricated using integrated thin film technology. It's about structure.

[Conventional technology]

In recent years, in the field of magnetic recording, recording densities have been increasing rapidly, and in magnetic heads that support magnetic recording as well as recording media, thin-film magnetic heads manufactured using integrated thin-film technology have been put into practical use, replacing conventional ferrite heads. It has been. This thin-film magnetic head has excellent frequency characteristics, and a manufacturing process based on semiconductor technology is applied, making it possible to manufacture high-precision, high-density magnetic heads at low cost, which will lead to future magnetic heads. It is becoming mainstream.

FIG. 5 is a schematic cross-sectional view showing the structure of such a thin film magnetic head. In FIG. 5, an insulating layer 12 such as A1203 is placed on a ceramic substrate 10 such as A1203-TiC.
The film is formed by a sputtering method or the like. Next, a NiFe alloy or a Co-metallic amorphous material (for example, Co
A lower magnetic layer 13 made of a soft magnetic material such as ZrNb) is formed using integrated thin film technology. Thereafter, an insulator 14 having a thickness equal to a predetermined gap length is formed.

Next, an organic layer 15 which becomes a step eliminating layer for the lower magnetic layer 13 is formed, and a coil 16 made of a conductive material is formed. After that, the organic layer 17, which becomes the layer for eliminating the step difference in the coil 16, is formed again using a zero-order NiFe alloy or Co.
- The upper magnetic layer 18 made of a soft magnetic material such as a metallic amorphous material (for example, CoZrNb) is formed in the same manner as the lower magnetic layer 13 to form a magnetic circuit. Thereafter, a protective layer (not shown) made of an insulating material is deposited to complete the transducer of the thin film magnetic head.

The coil 16 of the thin film magnetic head described above is usually made of a Cu film formed by electroplating, and its cross-sectional structure is as shown in FIG. In other words, the coil 16 is made of Cr.
It has a laminated structure of a plating base layer consisting of a laminated body of layer 1 and Cu layer 2 and Cu plating layer 3. The manufacturing process of such a conventional coil is shown in FIG. 4. In FIG. 4(a), a laminate of a Cr layer and a Cu layer 2 is formed by sputtering on a base body 11 to form a plating base layer. . Then,
As shown in FIG. 4(b), a photoresist pattern (hereinafter abbreviated as PR pattern) 4 having a predetermined shape is formed using a known exposure and development technique. After that, see Figure 4 (
As shown in c), Cu is deposited in a plating medium containing copper sulfate as a main component to form a Cu plating layer 3. Next, the PR pattern 4 is peeled off (FIG. 4(d)),
As shown in Figure (e), a portion of the plating base layer covered with the PR pattern 4 is removed by ion etching in an Ar gas atmosphere to form a coil. As is clear from FIG. 4(e), the Cu plating layer 3 is also ion-etched in this plating base layer removal process, so the thickness of the Cu plating layer 3 is equal to the time required to remove the plating base layer. Decrease.

Incidentally, reflecting the trend toward higher recording densities in recent years, the leakage magnetic field from information recorded on a medium is becoming smaller and smaller, and there is a concern that the reproduction output of the head will decrease. Since the reproduction output of an inductive thin film magnetic head is approximately proportional to the number of turns of the coil, it is best to narrow the coil spacing as much as possible to form a dense coil and increase the number of coil turns.
This is considered to be one effective means of compensating for this reduction in reproduction output.

[Problem to be solved by the invention]

However, with the conventional structure and manufacturing method described above, there are problems as described below when increasing the number of coil turns. That is, in dense coils, the coil spacing is naturally narrower than the conventional coil spacing (about 4 μm), and is usually about 2 μm or less. on the other hand,
The coil thickness (the sum of the thickness of the plating base layer and the Cu plating layer 3) is currently around 3 μm, but in order to reduce the effect of an increase in coil resistance due to an increase in the number of coil turns, it can be made thicker (for example, 4 μm or more). In such a dense coil with narrow coil spacing and thick coil thickness,
When removing a part of the plating base layer covered with PR pattern 4 by ion etching (step shown in Fig. 4(e)), compared to forming a conventional coil with a wide coil spacing, the plating base layer is The time required for the layer removal process increases significantly. This is because the coil spacing is narrow and the coil thickness is large, so the plating base layer that should be removed is the top surface of the coil (second layer).
This means that the Ar particles reach the plating base layer less frequently, and the plating base that has been knocked out by the Ar particles re-attaches to the side surface of the coil. This phenomenon is thought to be caused by the fact that the effective etching speed in the area sandwiched between the coils decreases due to the fact that the etching does not easily separate from the space between the coils. . In the process of removing the plating underlayer of such a dense coil, it takes a long time to complete the process, and as a result, the upper surface of the coil is ion-etched for a long time, resulting in a significant reduction in the coil thickness. Therefore, the effect of increasing the coil thickness to suppress an increase in coil resistance due to an increase in the number of turns cannot be sufficiently obtained, which has been a problem. This problem becomes more pronounced as the coil thickness becomes thicker and as the coil spacing becomes narrower, and has become a major problem in the head manufacturing process.

It is an object of the present invention to solve the above-described problems in the coil forming process of a thin film magnetic head.

[Means to solve the problem]

The present invention provides an induction circuit comprising a magnetic circuit made of a magnetic material, a magnetic gap made of a non-magnetic material formed in the magnetic circuit, and a coil made of a conductive thin film formed to cross the magnetic circuit. In the type thin film magnetic head, the coil is composed of a laminate in which a plating base layer, a Cu plating layer, and a carbon layer are formed in this order.

[Effect]

By adopting the above-described structure, the present invention has made it possible to provide a thin film magnetic head that solves the conventional problems. That is,
According to studies conducted by the present inventors, the ion etching rate of carbon in an Ar gas atmosphere is extremely low, and by laminating a carbon layer on a Cu plating layer, the Cu plating can be removed during ion etching in the plating base layer removal process. It has been found that the C11 plating layer can be completely prevented from being etched by protecting the layer. For example, if the plating base layer removal process requires 25 minutes, the carphone ion etching rate is 40 people/min (Ar gas pressure I
X 10 Torr, accelerating voltage 500 V), by creating a structure in which a carbon layer with a thickness of at least about 1000 people is laminated on the Cu plating layer,
Ion etching of the Cu plating layer can be almost completely prevented.

On the other hand, in the conventional coil, the ion etching speed of Cu is about 1000 people (ion etching conditions are the same as for carbon), and the Cu plating layer is directly converted into Ar particles, so the Cu plating layer has a thickness of about 1.25 μm. Ion etching occurs, and the coil resistance value increases by this amount. Note that if the plating base layer removal step requires a longer time, the thickness of the carbon layer may be increased as appropriate.

〔Example〕

Next, the present invention will be explained in detail using the drawings. As already mentioned, the present invention is characterized by the coil structure of the inductive thin film magnetic head, and the general structure of the thin film magnetic head according to the present invention is not much different from the structure of the conventional thin film magnetic head shown in FIG. In the following embodiments, components other than the coil portion will be explained using FIG. 5.

1) Example In FIG. 5, an insulating layer 12 made of an Al2O3 film is formed on an A120S-TiC ceramic substrate 10 by a sputtering method (throwing type crab 600W, Ar gas pressure crab 5X).
A film with a thickness of 10 μm was formed at a pressure of 10 −3 Torr. Next, a CoB7Zr5NbB film having a thickness of 3 μm was formed using a sputtering method, and a lower magnetic layer 13 was formed using a known photolithography technique. Furthermore, CoB7Zr5N
The conditions for forming the bB film were an injection type 600W Ar gas pressure of 5×10 Torr, and after the film was formed, it was annealed at 250° C. for 1 hour in a rotating magnetic field of 4800 e to improve the magnetic properties.

After that, the film thickness equal to the predetermined gap length is 0°2 μm).
An Al2O3 film with
) The L insulating layer 14 was used. Then, the lower magnetic layer 1
3, a photoresist made of a novolac resin is applied to a thickness of 4 μm and cured by heat treatment at 250° C. for 1 hour, thereby forming an organic layer 15 that becomes a step-resolving layer for the lower magnetic layer 13.
was formed, and then the coil 16 was formed.

The manufacturing method and structure of the coil 16 will be explained below in Figures 3 and 1.
This will be explained in detail using figures. In FIG. 3, the base body 11
A plating base layer consisting of a laminated film of Cr layer 1 (film thickness 30 layers) and Cu layer 2 (film thickness 2000 layers) was formed on (corresponding to organic material 15 in this example) using a sputtering method. Figure 3(a)). Next, a PR pattern 4 that will become a plating frame is formed using a known photolithography technique.
was formed (Fig. 3(b)). The photoresist used was a commercially available novolak resin resist. Further, the film thickness of the PR pattern 4 was 6 μm, the pattern width was 1.5 μm, and the pattern interval was 3 μm. In addition, since the pattern width of PR pattern 4 is 1.5 μm, the coil spacing is 1.5 μm.
It is m.

After that, to form a Cu plating layer 3 by electroplating Cu in a copper sulfate bath (Fig. 3(c)), the plating current density is 0.5 A/cm2, and the thickness of the Cu plating layer 3 is The thickness was 5 μm. Next, a carbon layer 5 with a thickness of 2,000 mm is formed on the Cu plating layer 3 by a vapor deposition method using an electron beam (FIG. 3(d)). The emission current of the electron gun at this time was 60 mA. Next, PR pattern 4 was peeled off in an organic solvent. (Figure 3(e)), and finally Ar
The unnecessary plating base layer was removed by ion etching in an atmosphere, and the coil 16 was formed as shown in FIG. 3 (f>). The ion etching conditions are Ar gas pressure I x 10-'
Torr, acceleration voltage 500V. Also, the time required for this plating base layer removal process was approximately 25 minutes, and during this time, the carbon layer 5 was etched by 1000 out of 2000 layers because the ion etching rate was 40 people/minute. The Cu plating layer 3 was not ion-etched at all. The schematic structure of the coil formed in this way is as shown in Figure 1.
It has a structure in which a stacked film of 1), a Cu plating layer 3, and a carbon film 5 are stacked in this order.

After forming the coil 16 as shown in FIG. 5 in the above manner,
A photoresist layer 17 serving as a step eliminating layer for the coil 16 was formed in the same manner as the photoresist layer 15 described above.

Next, an upper magnetic layer 18 made of a CoB7Zr5Nb6 film having a thickness of 3 μm was formed in the same manner as the lower magnetic layer 13. Finally, a protective film (not shown, 25 μm in film thickness) consisting of an At203 film was formed by sputtering. The film forming conditions are injection type crab 800W, Ar gas pressure = 5 x 10
""Torr.

In the thin film magnetic head of this example manufactured as described above, the coil spacing was 1°5 μm because the carbon film protects the Cu plating layer during the removal process by ion etching of the plating underlayer as described above. Although the coil was narrow and the coil thickness was as thick as approximately 5 μm, the Cu plating layer was not etched at all. Therefore, the coil thickness decreases and
The conventional problem of increased coil resistance does not occur. In addition, in order to easily remove the carbon film on the PR pattern 4 when peeling off the PR pattern 4 (step in FIG. 3(e)), the PR pattern forming step (step in FIG. 3(b)) is performed. ), it is desirable that the cross-sectional shape of the PR pattern 4 is a stencil shape.

2) Comparative Example An insulating layer 12, a lower magnetic layer 13, an insulating layer 14 serving as a gap, and an organic layer 15 were formed on an A1203-TiC ceramic substrate 10 in the same manner as in the example, and then a coil 16 was formed. The coil 16 was formed using the conventional coil forming method shown in FIG. That is, in FIG. 4, a Cr layer 1 (thickness of 30 layers) and a 00 layer 2 (thickness of 2000 layers) are formed on the base body 11 (corresponding to the organic layer 15 in FIG. 5 in this example) using a sputtering method. 4(a)). Then,
A PR pattern 4 that will become a plating frame is formed using a known photolithography technique (FIG. 4(b)).

The photoresist used was a commercially available novolak resin resist. Also, PR pattern 4 has a film thickness of 6 μm, a pattern width of 1.5 μm, and a pattern interval of 3 μm, as in the example.
It was set as μm. In addition, the pattern width of PR pattern 4 is 1.5
μm, the coil spacing is 1°5 μm. Thereafter, Cu is electroplated in copper sulfate to form a Cu plating layer 3 (FIG. 4(C)). Here, the plating current density is 0.5A/cm2, and the thickness of the Cu plating layer 3 is 5μ.
It was set as m. Next, the PR pattern 4 was peeled off in an organic solvent (FIG. 4(d)). Finally, remove the unnecessary plating base layer by ion etching in an Ar atmosphere (Figure 4(e)).
, a coil 16 was formed. The conditions for ion etching are Ar gas pressure 1X10-4 Torr and acceleration voltage 500.
■It is. The time required for this plating base layer removal process was approximately 25 minutes, but since the ion etching rate of C11 is 600 people/min under the above ion etching conditions, the Cu plating layer 3 was etched by 1.5 μm during this time. It was done.

After forming the coil 16 as described above, a photoresist layer 17 and a Co67Zr layer are formed to eliminate the step difference in the coil 16.
An upper magnetic layer 18 made of a 5NbB film was formed in the same manner as in the example. Finally, a protective film (not shown, 25 μm thick) made of Al2O was formed by sputtering. The film forming conditions in this case are also the same as in the example.

In the thin film magnetic head of this comparative example manufactured as described above, as described above, the 1.5 μm thick Cu was etched in the step of removing the plating base layer by ion etching, and the thickness of the Cu plating layer 3 was increased. Diminished. For this reason, it was originally supposed to have almost the same coil resistance value as the coil of the thin-film magnetic head mentioned in the example, but about 3
The coil resistance value was greater than 0%.

〔Effect of the invention〕

As described above, according to the present invention, even in a thin film magnetic head having a dense coil with a narrow coil spacing and a large coil thickness, the coil can be removed during ion etching in the plating underlayer removal step during the coil forming process. Even if the upper surface is ion-etched for a long time, the coil pressure will not decrease because the carbon layer, which has a low ion-etching rate, protects the surface of the Cu plating layer. Therefore, the effect of increasing the coil thickness and suppressing an increase in coil resistance value due to an increase in the number of turns is fully exhibited.

As described above, according to the present invention, it is possible to solve problems in the coil forming process of a thin film magnetic head having a dense coil with a large number of turns, and its industrial value is high.

In addition, in the above description, only the example using the vapor deposition method as a film-forming method of the carbon film was mentioned, but the sputtering method or the CVD method may also be used. Further, in the embodiment, only an example in which the magnetic circuit is formed entirely from a soft magnetic thin film is mentioned, but the present invention can also be applied to a magnetic head in which a part of the magnetic circuit is formed from a bulk material, such as by using a ferrite substrate. Of course, the intended purpose remains intact.

Method 1 Cause

[Brief explanation of the drawing]

1 and 3 are diagrams for explaining the present invention, and FIGS. 2 and 4 are diagrams for explaining the prior art. Further, FIG. 5 is a schematic cross-sectional view showing the structure of an induced telescopic magnetic head according to the present invention. In the figure, 1...Cr layer, 2...Cu layer, 3...
-Cu plating layer, 4...PR pattern, 5...carbon layer, 10...substrate, 11...base body, 12.1
4... Insulating layer, 13... Lower magnetic layer, 15.17
. . . organic material layer, 16 . . . coil, 18 . . . upper magnetic layer. t 2 diagram

Claims (1)

[Claims] Inductive thin film magnetism consisting of a magnetic circuit made of a magnetic material, a magnetic gap made of a non-magnetic material formed in the magnetic circuit, and a coil made of a conductive film formed to cross the magnetic circuit. 1. A thin-film magnetic head, wherein the coil is made of a laminate in which a plating underlayer, a Cu plating layer, and a carbon layer are formed in this order.