JPH025219A - Production of thin film magnetic head - Google Patents

Abstract

PURPOSE:To improve the sensitivity of a magneto-resistance element and to ensure the high output by applying a dry etching process to a prescribed area of an upper yoke positioned on an organic film after the forming process of the upper yoke and processing this yoke. CONSTITUTION:A ferromagnetic thin film serving as an upper yoke 18 is formed by a sputtering process over a magneto-resistance MR element 15. Then a resist film 19 is formed over the yoke 18 by the photolithography and then processed into a prescribed pattern. Then the sputtering method like a dry etching process is carried out to delete a prescribed area of the yoke 18 positioned on an organic film 17, and the physical processing is applied to the yoke 18. Thus the yoke 18 is processed with high accuracy and the sensitivity of the element 15 is improved to ensure the high output.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thin film that detects signals recorded on a magnetic recording medium using a magnetoresistive element (hereinafter referred to as an MR element). The present invention relates to a method of manufacturing a magnetic head (hereinafter referred to as an MR head).

[Conventional technology]

It is known that MR heads have many advantages over wire-wound magnetic heads. In other words, the MR head is a so-called magnetic flux responsive head that detects signals recorded on a magnetic recording medium by extracting internal resistance changes of the MR element according to changes in the magnetization direction to the outside. This has the advantage that signals can be reproduced without depending on the transport speed of the magnetic recording medium. In addition, MR beds have the advantage of being easy to achieve high integration and multi-element by applying semiconductor microfabrication technology.
It is particularly promising as a magnetic head for reproduction in fixed head PCM recorders that perform high-density recording.

However, since such an MR element has a sensitivity characteristic that shows a square change with respect to an external magnetic field, when the MR element is configured as a read head, it is necessary to apply a predetermined bias magnetic field. Known methods for applying this bias magnetic field include a method of inducing a bias magnetic field by flowing a direct current through a bias conductor, and a method of applying a bias magnetic field using a high coercive force thin film such as a C0-P layer. There is.

Furthermore, compared to an MR head composed of a single MR element, the MR
A yoke-type MR head (hereinafter referred to as a YMR head), in which the element is separated from the head tip and the magnetic flux introduction path is formed by a yoke to guide the signal magnetic field from the magnetic recording medium to the MR element, has better signal resolution ability and durability. It is known to be superior in terms of

To manufacture a YMR heft, as shown in FIG. 3(a), a first insulating layer 2 made of SiO, SiO□, etc. is formed on a lower yoke 1 made of Ni-Zn ferrite or Mn-Zn ferrite. After forming by RF sputtering method, resistance heating method, etc., A1, A1-Cu
Alternatively, a conductive layer of Cu or the like is formed by RF sputtering, resistance heating, etc., and then this conductive layer is processed by dry etching, chemical etching, etc. to obtain a bias conductor 3 for applying a bias magnetic field. Next, a second insulating layer 4 is formed to cover this bias conductor 3.

Next, as shown in FIG.
After forming a ferromagnetic thin film that will become the R element 5 by a vapor deposition method or a sputtering method, it is processed into a predetermined shape.

Thereafter, as shown in FIG. 5(c), the first and second insulating layers 2 and 4 are taper-etched using the RlE (reactive ion etching) method, and then the MR element 5 is etched.
The third insulating layer 6, which functions as a spacer layer between the upper yoke 7 and the upper yoke 7 described later and as a gap layer of the front gap portion A, is made of SiO, SiO, etc.
It is formed by a sputtering method or the like.

Next, as shown in FIG. 3(d), an upper yoke 7 made of a Ni-Fe alloy film is formed by sputtering, and then
As shown in e), a YMR head is obtained by processing this upper yoke 7 into a predetermined pattern by chemical etching or dry etching.

[Problem to be solved by the invention]

Incidentally, the track width of the MR element 5 is set to about 30 to 200 μm when a multi-trunk configuration is adopted.

On the other hand, in order to increase the sensitivity of the Δρ/ρ characteristic of the MR element 5 and obtain high output, the width W of the MR element 5 must be sufficiently narrow (necessary) with respect to the above-mentioned track width. must partially overlap the upper yoke 7 in a three-dimensional intersection.

Here, in the machining of the upper yoke 7 shown in FIG. 3(e), if the side etching amount B is large, the above-mentioned overlapping portion will be reduced. Therefore, in order to enlarge the overlapping portion, it is necessary to increase the above-mentioned width W, and therefore, the narrowing of the width W is limited by the processing accuracy of the upper yoke 7. In particular, chemical etching involves a very large amount of side etching, so the width W needs to be 20 μm or more, making it impossible to obtain a high-output MR element 5.

In this regard, if the upper yoke 7 is processed by a dry etching method, for example, a sputter etching method, a relatively good processing accuracy can be obtained, so the width W of the MR element 5 can be increased from 5 to 50% while ensuring the above-mentioned overlapping area. It is possible to suppress the thickness to about 20 μm.

However, etching using such a dry etching method has poor selectivity (etching speed ratio) between the workpiece and other films, causing other problems and making it impossible to improve the performance of the YMR head. That is the reality.

That is, the thinner the third insulating layer 6 is, the better the MR
As the distance between the element 5 and the upper yoke 7 becomes shorter, the magnetic resistance of the head becomes smaller, so a higher reproduction output can be obtained, and the gap length also becomes smaller, which improves the resolution of the head. When the upper yoke 7 is etched by the etching method, the third insulating layer 6 is also etched due to the poor selectivity, and if the third insulating layer 6 is thin, the MR element 5 is partially etched. You will end up being rejected. For this reason, the thickness of the third insulating layer 6 cannot be made sufficiently thin, and the performance of the YMR head cannot be sufficiently improved.

Specifically, the film thickness of the upper yoke 7 is set to 0.5 μm or more in consideration of the frequency characteristics and reproduction output of the YMR head. Further, the film thickness of the MR element 5 is 200 to 50
Very thin with 0 people. In this case, considering variations in the thickness distribution of the upper yoke 7 and non-uniformity of etching, the MR element 5 may be partially etched when the thickness of the third insulating layer 6 is 0.3 μm or less. There is a risk that this will happen.

[Means to solve the problem]

In order to solve the above problems, a method for manufacturing a thin film magnetic head according to the present invention provides a magnetoresistive effect in which a change in an applied signal magnetic field is detected as a change in electrical resistance of a ferromagnetic thin film having uniaxial magnetic anisotropy. In a method of manufacturing a thin film magnetic head comprising an element and upper and lower yokes forming four magnetic flux paths for guiding the signal magnetic field to the magnetoresistive element, an insulating layer is formed on the magnetoresistive element. a step of forming an organic film on the insulating layer between the step and the step of forming the upper yoke; and after the step of forming the upper yoke, forming an organic film on the upper yoke. The method is characterized in that it includes a step of processing the upper yoke by performing dry etching on a predetermined portion thereof.

[For production]

According to the above configuration, since the upper yoke is processed by dry etching, the upper yoke can be processed with high precision.Therefore, it is possible to reduce the width of the magnetoresistive element. , it is possible to increase the sensitivity of the magnetoresistive element and achieve high output.

On the other hand, partial etching of the magnetoresistive element due to poor selectivity in dry etching is reliably prevented because the organic film acts as a stopper. Therefore, it is permissible to reduce the thickness of the insulating layer formed on the magnetoresistive element, and it is possible to improve reproduction output and resolution.

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 and 2.

As shown in FIG. 2, a yoke-type magnetoresistive element type thin-film magnetic head (hereinafter referred to as a YMR head) manufactured by the method for manufacturing a thin-film magnetic head according to the present invention has a lower yoke 11 and a lower yoke 11. a first latitudinal edge layer 12, a bias conductor 13 that induces a bias magnetic field, a second insulating layer 14, and a magnetic field that detects changes in the applied signal magnetic field as changes in electrical resistance of a ferromagnetic thin film having uniaxial magnetic anisotropy. A resistive effect element (hereinafter referred to as an MR element) 15, a third insulating layer 16, and an organic film 17 such as a resist (in the case of resist, it is desirable to remove it eventually) or PIQ (polyimide resin). , and the lower yoke 11 to reduce the signal magnetic field to M.
The R element 15 is provided with an upper yoke 18 that forms a magnetic flux introduction path.

To manufacture a YMR heft, as shown in FIG. 1(a), a first insulating layer 12 made of StO, St, etc. is placed on a lower yoke 11 made of Ni-Zn ferrite, Mn-Zn ferrite, etc. is formed by an RF sputtering method, a resistance heating method, etc., and then At, , A are formed on this first insulation N12.
A conductive layer of /-Cu or Cu is formed by RF sputtering, resistance heating, etc., and then this conductive layer is processed by dry etching, chemical etching, etc. to form a bias conductor 13 for applying a bias magnetic field. obtain.

Next, a second insulating layer 14 is formed to cover this old bias body 13. Next, a ferromagnetic thin film that will become the MR element 15 is formed on the second insulating layer 14 by vapor deposition, sputtering, or the like, and then processed so that its width W1 falls within the range of 5 to 20 μm. Thereafter, the first and second insulating layers 12 and 14 are taper-etched by RIE (reactive ion etching), and then used as a spacer layer between the MR element 15 and an upper yoke 18, which will be described later, and as a front gap. The third insulating layer 16, which functions as a gap layer in part A1, is made of SiO, 5i02, etc., and is formed with a film thickness of 0.1 to 0.1 by RF sputtering or P-CVD.
It is formed to have a thickness of about 0.3 μm.

Next, as shown in FIG. 3B, an organic film 17 such as a positive resist, a negative resist, or PIQ is formed on the third insulating layer N16 on the MR element 15 by photolithography. The width of the structure 17 is determined by the width W of the MR element 15 from the viewpoint of the reproduction output and frequency characteristics of the YMR head.
It is set to about 40 to 90% of 1. In addition, organic film 1
The film thickness of No. 7 is set to 0.3 to 3 μm. Note that since the resist normally deteriorates at temperatures above 200° C., it is preferable to peel it off after processing the upper yoke 18, which will be described later. On the other hand, since PIQ does not change in quality even at 200° C. or higher, it does not need to be peeled off after processing the upper yoke 18, and the effort of this peeling can be saved.

Next, as shown in FIG. 3C, a ferromagnetic thin film (such as a Ni--Fe alloy film) that will become the upper yoke 18 is formed by sputtering or the like so as to straddle the MR element 15. The thickness of the upper yoke 18 is set to 0.5 μm or more from the viewpoint of the reproduction output and frequency characteristics of the YMR head.

Thereafter, a resist film 19 is formed by photolithography to cover the upper yoke 18, and is processed into a predetermined pattern. Next, the upper yoke 18
The upper yoke 18 is physically processed by removing a predetermined portion located on the organic film 17 using a dry etching method such as a sputtering method or an ion milling method.

When processing using the ion milling method, pure argon gas is used as the introduced gas, and the flow rate is 8.53CC.
M, degree of vacuum I
．． When the condition of 3A is set, Ni-F becomes the upper yoke.
The etching speed of the e-alloy film is approximately 30 people/min, and the amount of side etching can be suppressed to within -0.5 .mu.m.

When the dry etching is completed, the resist film 19 is peeled off. If a resist is used as the organic film 17, the resist is also peeled off at the same time as the resist film 19 is peeled off. On the other hand, when PIQ is used as the organic film 17, only the resist film 19 is removed.

As described above, according to the method for manufacturing a thin film magnetic head according to the present invention, the upper yoke 18 is processed by dry etching, so that the upper yoke 18 can be processed with high precision. That is, as described above, side etching ff1B1 can be suppressed to within 0.5 μm. This makes it possible to set the width W1 of the MR element 15 to approximately 5 to 20 μm.
By increasing the sensitivity of the Δρ/ρ characteristic of No. 5, high output can be achieved.

On the other hand, partial etching of the MR element 15 due to poor selectivity in dry etching is reliably prevented because the organic film 17 functions as a stopper. Therefore, it is permissible to reduce the thickness of the third insulating layer 16, and it is possible to improve the reproduction output and the resolution in the YMR head.

〔Effect of the invention〕

As described above, the method for manufacturing a thin film magnetic head according to the present invention includes a magnetoresistive element that detects a change in an applied signal magnetic field as a change in electrical resistance of a ferromagnetic thin film having uniaxial magnetic anisotropy; A method for manufacturing a thin film magnetic head comprising upper and lower yokes forming a magnetic flux introduction path for guiding a signal magnetic field to a magnetoresistive element, the step of forming an insulating layer on the magnetoresistive element, and the step of forming an insulating layer on the magnetoresistive element; a step of forming an organic film on the insulating layer between the step of forming the yoke, and a predetermined portion of the upper yoke located on the organic film after the step of forming the upper yoke; The structure includes a step of processing the upper yoke by dry etching.

Thereby, the width of the magnetoresistive element can be reduced, and the sensitivity of the magnetoresistive element can be increased to achieve high output. Furthermore, since it is permissible to reduce the thickness of the insulating layer formed on the magnetoresistive element, it is also possible to improve the reproduction output and resolution of the thin-film magnetic head.

[Brief explanation of the drawing]

FIGS. 1 and 2 show an embodiment of the present invention, and FIGS. 1(a) to d) respectively show Y M R
A cross-sectional view showing each stage of the head manufacturing process, Figure 2 is YM
A cross-sectional view of the R head, FIG. 3, shows a conventional example, and FIGS. 3(a) to 3(e) are cross-sectional views showing each stage of the manufacturing process of the YMR head. 11 is a lower yoke, 12 is a first insulating layer, 13 is a bias conductor, 14 is a second insulating layer, and 15 is a magnetoresistive element (M
R element), 16 is a third insulating layer, 17 is an organic film, and 18 is an upper yoke. Diagram (a) Funeral diagram 3VA (b) Stone diagram (C) Happy diagram (d) Funeral diagram (e)

Claims (1)

[Claims] 1. A magnetoresistive element that detects a change in an applied signal magnetic field as a change in electrical resistance of a ferromagnetic thin film having uniaxial magnetic anisotropy; In a method of manufacturing a thin film magnetic head having upper and lower yokes forming a guiding magnetic flux introduction path, between the step of forming an insulating layer on the magnetoresistive element and the step of forming the upper yoke, , comprising the step of forming an organic film on the insulating layer, and after the step of forming the upper yoke, dry etching is performed on a predetermined portion of the upper yoke located on the organic film to form the upper yoke. 1. A method of manufacturing a thin film magnetic head, comprising a processing step.