JPH02230505A - Thin film magnetic head and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a dense coil with a small coil gap without applying etching on the upper plane of a Cu plating layer by forming a plating substrate layer with a Ta or Ti film, and eliminating the plating substrate layer by applying reactive etching in CF gas atmosphere. CONSTITUTION:The plating substrate layer consisting of a Ta layer 2 is formed on a substrate body(equivalent to an organic material layer 15) by using a sputtering method, and next, a PR pattern 4 which becomes a plating frame is formed by using photolithographic technique. After that, the Cu plating layer 3 is formed in a copper sulfate bath. Next, the PR pattern 4 is peeled in organic solvent, and lastly, an unrequired plating substrate layer is eliminated by the reactive etching in the CF gas atmosphere, then, a coil 16 is formed. Furthermore, an organic material layer 17 consisting of photoresist which becomes the gap elimination layer of the coil 16 is formed. Thereby, it is possible to minimize the reduction of the film thickness of the Cu plating layer in process to eliminate the plating substrate layer in the generating process of the coil, and to obtain the fine coil with a narrow coil gap and with large coil thickness.

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 an inductive thin film magnetic head manufactured using integrated thin film technology. This relates to the structure of the coil of the magnetic head.

[Prior Art] In recent years, in the field of magnetic recording, recording densities have been increasing rapidly, and magnetic heads that support magnetic recording as well as recording media have been increasing.
Thin film magnetic heads manufactured using integrated thin film technology have been put into practical use in place of the conventional Ferray 1 head.

This thin-film magnetic l\t has excellent frequency characteristics and can be applied to manufacturing processes based on semiconductor technology, making it possible to manufacture high-precision, high-density magnetic heads at low cost, making it possible to manufacture future magnetic heads. It is becoming mainstream.

FIG. 5 is a schematic cross-sectional view of such a thin film magnetic head. In FIG. 5, Af! On a ceramic substrate 10 such as 203-TIC, an insulating layer 12 of Af203 or the like is formed by sputtering or the like, and on top of that is a NiFe film.
Alloys and Co-metallic amorphous materials (e.g. CoZrNb)
A lower magnetic layer 13 made of a soft magnetic material such as the above is formed using integrated thin film technology. On the magnetic layer 13, an insulator @ 14 having a film thickness equal to a predetermined cap length, an organic layer 15 serving as a layer for eliminating the step of the lower magnetic layer 13, and a coil 16 made of a conductive material are formed. . On the coil and in the coil gap, an organic layer 17 is formed again to serve as a level difference eliminating layer of the coil 16, and then an organic layer 17 made of a soft magnetic material such as an NFC alloy or a Co-metallic amorphous abrasive (for example, Co7rNb) is formed. The upper magnetic material @18 is the lower magnetic material layer 13
A protective layer (not shown) made of an insulating material is formed in the same manner as described above, and one Heransducer of a thin film magnetic head is completed.

The coil 16 of the thin film magnetic head described above is usually made of electrolytic copper (
A Cu) plating film is used, and its schematic cross-sectional structure is as shown in FIG. In other words, the coil 16 shown in FIG. 5 has a layered structure of a plating base layer consisting of a laminate of Cr@5 and a Cu layer 6 (this laminate is usually formed by sputtering) and a Cu plating layer 3. It becomes.

The manufacturing process of such a conventional coil is shown in FIG. First, in FIG. 4(a), a laminate of an Or layer 5 and a Cu layer 6 is formed on the base body 11 by sputtering,
Form a plating base layer. Next, as shown in FIG. 4(b), photoresist 1 to pattern (hereinafter referred to as
(abbreviated as PR pattern) 4 is formed using a known exposure and development technique.

Thereafter, as shown in FIG. 4(C), Cu is deposited in a plating bath 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)), and as shown in FIG. 4(e), the plating base layer that was covered with the PR pattern 4 is etched by ion etching in an Ar gas atmosphere. A portion of the coil is removed to form a coil. In this manufacturing process, as is clear from FIG. 4(e), the Cu plating layer 3 is also ion-etched in the step of removing the plating base layer.
The thickness of the plating layer decreases by the amount of time it takes to remove the plating underlayer.

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 induction thin-film magnetic head is approximately proportional to the number of turns of the coil, one effective way to compensate for this decrease in reproduction output is to narrow the coil spacing as much as possible to form a dense coil and increase the number of coil turns. considered a means.

[Problem to be Solved by the Invention 1] However, due to the conventional structure and manufacturing method described above, there were problems as described below when increasing the number of turns of the coil.

That is, in dense coils, the coil spacing is naturally narrower than the conventional coil spacing (about 4 square meters), 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, or thicker to reduce the effect of increased coil resistance due to an increase in the number of coil turns. (for example, 4 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 in the step of FIG. 4(e), the coil Compared to forming conventional coils with wide spacing, the time required for the plating underlayer removal process increases significantly.

This is because the coil spacing is narrow and the coil thickness is large, so the plating base layer to be removed is located deep from the top surface of the coil (the surface indicated by the arrow in Figure 2), and Ar particles are deposited under the plating. The frequency of reaching the strata will decrease, and the plating base that has been knocked out by Ar particles will re-adhere to the sides of the coils and will not easily separate from the gaps between the coils. This phenomenon is thought to be due to a decrease in the effective etching rate in the exposed areas, and is an inevitable phenomenon.

In this way, a
Since it takes a long time to complete the process, the coil itself (the surface indicated by arrow A in FIG. 2) is ion-etched for a long time, resulting in a significant reduction in the coil thickness. Therefore, the effect of increasing the coil thickness and suppressing 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 distance between the coils becomes narrower, and becomes a serious problem in the head manufacturing process.

The purpose of this defense is to solve the problems in the coil forming process of a small flat thin film magnetic head and to provide a thin film magnetic head having a dense coil with a thick coil thickness and narrow coil spacing, and a method for manufacturing the same. It is something.

[Means for Solving the Problems] The present invention provides a magnetic circuit made of a magnetic material, a magnetic gap made of a non-magnetic material formed in the magnetic circuit, and a conductor formed crossing the magnetic circuit. An inductive thin film magnetic head constituted by a coil made of a thin film, characterized in that the coil is formed of a laminate in which a thin film layer or a thin film layer and a Cu Meggi layer are sequentially formed. The coil manufacturing process in the method for manufacturing an inductive thin film magnetic head includes a step of forming a plating base layer on a substrate, and forming a photoresist corresponding to the coil shape on the plating base layer. It consists of a step of forming a pattern, a step of forming an electrolytic Cu plating layer in the gap between the photoresist patterns, a step of peeling off the photoresist pattern, and a step of removing the exposed plating base layer. The plating base layer is removed by reactive etching in an atmosphere containing CF4 gas as a main component.

[Function] By adopting the above-described structure, the present invention makes it possible to provide a thin film magnetic head that solves the conventional problems.

That is, according to the investigation conducted by the present inventor, in reactive ion etching in an atmosphere mainly composed of CF4:/j, the etching rate of Taa film and Ti thin film is very high, while the etching rate of The etching rate of Ti is extremely low, about 1/15 of la, and about 1/2 of that of Ti.
It is about 0. Therefore, when the Ta layer or the Li layer is used as the plating base layer, it is possible to remove the unnecessary plating base layer without substantially etching the Cu plating layer.

For example, when using a la thin film with a thickness of 3000 as the plating base layer, the etching rate of Ta in a CF4 gas atmosphere is 300 min/min (C4 gas pressure 4.5 Pa, input power 100 W). The removal process of the plating base layer is completed in about 10 minutes.During this time, the Cu plating layer has an etching rate of about 20 people/min under the same etching conditions, so the thickness of the Cu plating layer is about 200. It only decreases.

On the other hand, when a thin film with a film thickness of 3000 is used as the plating base layer, the etching rate of T in a CF4 gas atmosphere is 400 people/min (CF4 gas pressure 4.5 Pa, input power 1
00W), the plating base layer removal process is completed in about 8 minutes. During this time, since the etching rate of Cu under the same etching conditions is about 20 per minute, the thickness of the Qu plating layer decreases by only about 160 per minute.

Therefore, by using a Ta or Ti thin film as a plating base layer, CF
4 By removing the plating base layer by reactive etching in a gas atmosphere, the top surface of the Cu plating layer is hardly etched during the plating base layer removal process, and it is possible to create dense coils with small coil spacing or real flat coils. be done.

Note that the etching speed of Ta or King in a CF4 gas atmosphere is different from that when the plating base layer is removed by ion milling in a △r gas atmosphere.
．． There is almost no coil spacing dependence up to about 8 ptn. Therefore, q of the plating base layer? The time it takes to leave does not change much.

[Example code] Next, embodiments of the present invention will be described with reference to the drawings.

As already mentioned, the inductive thin film magnetic head of the present invention is characterized by its coil structure, and the schematic structure of other parts of the thin film magnetic head of the present invention is shown in FIG. Since there is no major difference in structure from the conventional thin-film magnetic head, in the following embodiments, components other than the coil portion will be explained using FIG. 5.

Example 1 In FIG. 5, Aj! An insulating layer 12 made of an Aβ203 film is formed on a 203-T i C ceramic substrate 10 by a sputtering method (input power: 600W, 8R gas pressure: 5X10-3 Torr) to a film thickness of 10p.
The film was formed using m. Next, C○8■7r with a film thickness of 3lJIn
A 5Nb8 film was formed using a sputtering method, and a lower magnetic layer 13 was formed using a known photolithography technique.

td. Ah, the film forming conditions for the C O B 7 7 r s N b s film are input power: 600 W, Ar gas pressure: 5 x 10-3 Torr, and after film formation,
The magnetic properties were improved by annealing at 250° C. for 1 hour in a rotating magnetic field of 480 oe.

Thereafter, a sputtered Aρ203 film having a film thickness of 0.2 μm equal to the predetermined cap length was formed (input power: 3 μm).
00W, Ar gas pressure: 5xlO-3 Torr
) and used as the insulating layer 14. Next, on the lower magnetic layer 13, a photoresist made of a novolac resin is applied to a thickness of 4 coats, and heat treated at 250'C for 1 hour to cure and eliminate the step difference in the lower magnetic layer 13. An organic material layer 15 was formed, and then a coil 16 was formed.

Hereinafter, the manufacturing method and structure of the coil 16 will be explained in detail using FIGS. 1 and 3.

FIG. 3 is a partial cross-sectional view showing the method of manufacturing a coil according to the present invention in the order of steps. In the figure, a plating base layer consisting of a Ta layer 2 (thickness: 3000) was formed on a base body 1 (corresponding to the organic layer 15 in this example) using a sputtering method (Fig. 3(a)). ). The film forming conditions were input power: 600W, Ar scum pressure: 5 x 10-
3 Torr. Next, a PR pattern 4 which will become a plated frame is formed using a known photolithography technique (FIG. 3(b)).

The photoresist used was a commercially available novolac resin resist, and the film thickness of the PR pattern 4 was 6 μm, the pattern width was 1 strip, and the pattern interval was 3 μm.

Hey, the pattern width of PR pattern 4 is 1.
The coil spacing is 1 urn. Thereafter, Cu was electroplated in a copper sulfate bath to form a Cu plating layer 3 (third
Figure (C)). Here, the plating current density is 1A, and C
The thickness of the u plating layer 3 was 5IJIn.

Next, the PR pattern 4 is peeled off in an organic solvent (Fig. 3(d)). Finally, the unnecessary plating base layer was removed by reactive etching in a CF4 gas atmosphere (FIG. 3(e)), and the coil 16 was formed. Hey, the etching conditions are CF
4 gas pressure: 4.5 Pa, input power: 100W. The time required for this plating base layer removal process was about 10 minutes, but during this time, the Cu plating layer 4 required an etching rate of about 2OA/min, so about 200 layers of the 5IJIn film thickness were etched. However, the increase in coil resistance caused by this was almost negligible.

The schematic structure of the formed coil is shown in the first partial cross-sectional view.
As shown in the figure, it has a structure in which a plating base layer consisting of a la layer 2 and a Cu plating layer 3 are sequentially laminated.

After forming the coil 16 as described above, the coil 16
Organic material layer 1 made of foot resist, which becomes a layer to eliminate the step difference in
7 was formed in the same manner as the organic layer 15 described above. Next, an upper magnetic layer 18 made of a CO87Zr5Nb8 film having a thickness of 3 μm was formed in the same manner as the lower magnetic layer 13. Finally, a protective film consisting of 8β203 (not shown, film thickness approximately 2
5 μm) was formed into a film by sputtering method. The film forming conditions were: input power: 800W, Ar gas pressure: 5xlO-3
Torr.

In the thin film magnetic head of this example manufactured as described above, the coil spacing was as narrow as 11 JIn, and the coil thickness was as thick as approximately 5 JIn, but the etching amount of the Qu plating layer was approximately 200 JIn (coil thickness (approximately 0.4%), which was almost negligible. Therefore, the conventional problems of decreasing the coil thickness and increasing the coil resistance value do not occur.

Example 2 A thin film magnetic head was manufactured in the same manner as in Example 1 except that the Ta layer was replaced with the li layer.

In this example, the time required for the plating base layer removal process was about 8 minutes, and during this time, the Cu plating layer 4
Since the etching rate was about 20 people/min, about 160A of the film thickness of 5 was etched, but the increase in coil resistance caused by this was almost negligible. The schematic structure of the formed coil has a structure in which a plating base layer made of a Ti layer 2 and a Cu plating layer 3 are sequentially laminated, as shown in a partial cross-sectional view in FIG. Furthermore, although the obtained thin film magnetic head has a narrow coil spacing of 1 μm and a thick coil thickness of approximately 5 mm, the amount of etching of the Cu plating layer is approximately 160 mm (approximately 0.3 of the coil thickness).
%) and was almost negligible. Therefore, the conventional problems of decreasing the coil thickness and increasing the coil resistance value do not occur.

Comparative Example 1 An insulating layer 12, a lower magnetic layer 13, an insulating layer 14 serving as a cap, and an organic layer 15 were formed on an A1203TiC ceramic substrate 10 in the same manner as in Examples 1 and 2,
Thereafter, a coil 16 was formed. The coil 16 was formed using the conventional coil structure shown in FIG. 4 in the following manner.

That is, in FIG. 4, the base body 11 (in this example, the fifth
Cr layer 5 (film thickness: 30 mm) and Cu layer 6 (film thickness: 200 mm) are deposited on the organic material layer 15 (corresponding to the organic layer 15 in the figure) using a sputtering method.
A plating base layer consisting of a laminated film of 0 people was formed (4th
Figure (a)). Next, a PR pattern 4 which will become a plating frame is formed using the known 77I1 lithography technique (FIG. 4(b)).

The photoresist used was a commercially available novolak resin resist. Further, as in Examples 1 and 2, the PR pattern 4 had a film thickness of 6 Yanagi, a pattern width of 1 period, and a pattern interval of 3 JM. Also, since the pattern width of PR pattern 4 is 1 square meter, is it a coil question? is 1 k. Thereafter, U is electroplated in a copper sulfate bath to form a Cu plating layer 3 (FIG. 4(C)). Here, the plating current density is 0.5A
/c...2, and the thickness of the Cu plating layer 3 was 5 μm. Next, the PR pattern 4 was peeled off in an organic solvent (FIG. 4(d)). Finally, the unnecessary plating base layer was removed by ion etching in an Ar atmosphere (Fig. 4(e)), and the coil 1
6 was formed. The conditions for ion etching are Ar gas pressure: 1xlO-4 Torr, acceleration voltage: 50
It is 0V. The time required for this plating base layer removal process was approximately 25 minutes, but since the ion etching rate of Cu is 6008/min under the above-mentioned ion etching conditions, the Cu plating layer 3 was removed by 1.5 min. etched.

After forming the coil 16 in this way, the layer 17 from layer 7I-1 to regime 1, which becomes the layer for eliminating the step difference in the coil 16, and the upper magnetic layer 18 made of a CoBZr5Nb8 film are formed.
It was formed in the same manner as in Examples 1 and 2. Finally, Aβ2
A protective film (not shown, approximately 25 μm in thickness) consisting of a 0.03 film was formed by sputtering. The film forming conditions in this case are also the same as in the embodiments of the present invention.

In the thin film magnetic head of this comparative example manufactured in the above manner, as described above, in the plating base layer removal process by ion etching, Qu with a thickness of 1.5 mm was etched, and the CU plating layer 3 was etched. The film thickness decreased significantly. For this reason, although 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, it showed a coil resistance value that was about 30% larger.

Comparative Example 2 A Cu plating layer 3 was formed in exactly the same manner as in Comparative Example 1, and then the PR pattern 4 was peeled off using an organic solvent. Then, C
The unnecessary plating base layer was removed by reactive etching in an F4 gas atmosphere. The etching conditions were the same as in Example 1: CF4 gas pressure: 4.5 Pa, input power:
It is 100W. Since the etching rate of both Cu and C in a CF4 gas atmosphere is 20 people/min,
The process of removing the plating base layer took about 100 minutes. During this time, the Cu plating layer 3 was etched by about 2,000 people.

Although this etching area is small compared to the value in Comparative Example 1, it is about 10 times as large as in Example 1 and about 12 times as large as in Example 2. It is unavoidable that the coil resistance value increases accordingly. Furthermore, the time required for the plating underlayer removal step was approximately 100 minutes, which was an abnormally long time, and the throughput was extremely low, which was clearly a problem in the manufacturing process of the thin film magnetic head.

In the above explanation, an example using only Cf-< gas has been described, or other gases (for example, Ar.
2, N2, etc.) may be added in small amounts.

In addition, in the examples, only examples in which the magnetic circuit was formed entirely from a soft magnetic thin film were mentioned, but the present invention can also be applied to magnetic heads in which part of the magnetic circuit is formed from a bulk material, such as by using a ferrite substrate. Naturally, the intent of the invention is not impaired.

[Effects of the Invention] 16... Coil 18... Upper magnetic layer As explained above, according to the present invention, the reduction in the thickness of the Cu plating layer during the plating base layer removal step in the coil manufacturing process can be minimized. The coil spacing is narrow, and
In addition, it becomes possible to produce a dense coil with a large coil thickness.

Therefore, a thin film magnetic head for high recording density is realized.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a coil portion according to an embodiment of the present invention, FIG. 2 is a partial sectional view of a coil portion of a thin film magnetic head according to a conventional example, and FIG. FIG. 4 is a partial cross-sectional view of the coil portion showing the manufacturing method of a conventional thin-film magnetic head in order of process, and FIG. 5 is a schematic cross-sectional view of the inductive thin-film magnetic head of the present invention. It is. 1, 11... Base body 3... Cu plating layer 5... Cr layer 10... Substrate 13... Lower magnetic layer 2... Ti layer 4... PR pattern 6...Cu layer 12. 14... Insulating layer 15. 17...Organic layer

Claims (2)

[Claims] (1) An induction composed 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 thin film formed to cross the magnetic circuit. 1. A thin film magnetic head characterized in that the coil is formed of a laminate in which a Ta or Ti thin film layer and a Cu plating layer are sequentially formed. (2) The coil manufacturing process in the method for manufacturing an inductive thin film magnetic head includes a step of forming a plating base layer on a substrate, a step of forming a photoresist pattern corresponding to the coil shape on the plating base layer, and a step of forming a photoresist pattern corresponding to the coil shape on the plating base layer. It consists of a step of forming an electroplated Cu layer in the gap between the photoresist patterns, a step of peeling off the photoresist pattern, and a step of removing the exposed plating underlayer. A method for manufacturing a thin film magnetic head, characterized in that the method is carried out by reactive etching in an atmosphere containing the main components.