JPH03225611A - Manufacturing method of thin film magnetic head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thin film magnetic head of the type that slides on a recording medium, and particularly to a method of manufacturing a thin film magnetic head suitable for highly accurate track width control.

[Conventional technology]

In systems such as VTRs where the head runs in contact with the recording medium, there is the issue of ensuring the wear life of the head.
In particular, in order to apply a thin film magnetic head, it is necessary to develop one with a large gap depth. for that purpose,
In order to guide the magnetic flux to the tip of the gap, the core thickness must be increased so that the magnetic core does not become saturated on the way.

This, Ii! As a result of the study, it was determined that the gap depth should be 10 to 15 μm to ensure a long wear life. For this purpose, the thickness of the upper and lower magnetic cores must be about 20 tm.

However, it is not easy to form such a thick magnetic film by patterning with high precision. In a film magnetic head, there is a part where the patterned part extends over the underlying inclined part, and wet etching cannot be used because there is a large difference in the etching speed of the magnetic film between the inclined part and the flat part, so a method called ion milling is used. Process by dry etching. This ion milling method has the disadvantage of not having etching selectivity, and requires the mask material used during processing to have a film thickness comparable to that of the magnetic film, which poses problems in terms of accuracy.

It is difficult to control the track width by etching a film as thick as 20 pm with high precision. Therefore, as a conventionally proposed method, for example, Japanese Patent Application Laid-Open No. 63-30441
As described in Japanese Patent No. 3, there is a method of controlling the track width using a protrusion provided on the front portion of the lower magnetic core and a through hole provided in the coil insulating film.

[Problem to be solved by the invention]

According to the above-mentioned conventional technology, the object of highly accurate patterning is changed from a 20 μm magnetic film to a coil insulating film of about 10 μm, and the pattern accuracy is improved by reducing the film thickness by half.

However, if the tip of the lower core is formed to approximately the track width, it is necessary to align the tip of the lower core with the through hole of the coil insulating film. There was a problem in that it was difficult to ensure alignment accuracy.

FIG. 4 is an explanatory diagram of the sliding surface of a thin-film magnetic head manufactured by a conventional technique, and the figure shows a lower magnetic core 2 and a coil insulating film 4 having protrusions approximately the width of a track on the head sliding surface in contact with the medium. The through hole provided in ΔQ1. ΔQ2
It's off by just that. This Δ21. ΔQ2 is a combination of misalignment of the resist for through-hole formation, variation in the amount of dimensional change after etching due to variation in the thickness of the coil insulating film, etc.

In the photoetching technique, the photoresist as a mask material is positioned by a mask aligner by aligning markers on the substrate surface with markers on the photomask. In the above conventional technology, the coil insulating film is made of about 10 μm of Sin,
(transparent) and approximately 15μm of photoresist for a total of 25μ
There is a marker on the same plane as the lower core surface, m apart. Therefore, when aligning markers on a photomask, considering the space between the substrate surface and the photomask required for alignment work, it is necessary to align markers that are 50 to 601 tm apart, and from the viewpoint of depth of focus the microscope magnification It can only be used about 150 times, and the resist alignment is 1μ.
The accuracy of m was the limit. Also, the coil insulating film has a film thickness of 1
A distribution of about 1 μm inside the substrate is unavoidable compared to 0 μm. At this time, if the tape angle of the through-hole is 45°, the through-hole dimensions will vary by 2 μm within the board. Therefore, in the conventional technology, a through-hole position shift of about 3 μm may occur at worst.

In addition, among the above-mentioned conventional head construction techniques, the coil insulating film can be selectively etched with the underlying layer in order to provide through holes that serve as gap-forming surfaces, and it is also possible to selectively etch the coil insulating film with the underlying layer. In order to improve the magnetic properties of the core material, it is required to withstand heat treatment of 400°C or higher, and SiO□, which is an inorganic material, is often used. However, the thermal expansion coefficient of the substrate (e.g., Mn5Ni oxide ceramic material) and protective film (e.g., Sin, -MgO-based insulating film) matched to the magnetic film is 100.
X 10-'/'C or more, which is nearly two orders of magnitude smaller than that of SiO, and the hardness is greater than that of other materials. For this reason, 5
tOzffl causes large film stress, which may cause film peeling, flags on the substrate, etc., or cause sin when sliding with the medium.
, and the spacing loss increases. In other words, in the prior art, it is not possible to select the optimum material for the head constituting material in consideration of thermal expansion coefficient, sliding resistance, abrasion resistance, etc.

An object of the present invention is to provide a thin film head manufacturing method that does not cause misalignment between the tip of the lower core formed to the track width dimension and the through hole provided in the coil insulating film, that is, does not cause misalignment between the lower core and the upper core. Our goal is to provide the following. Another object of the present invention is to provide a method for manufacturing a head by arbitrarily selecting a material for forming the head.

[Means for solving the problem] The above object is to provide a new thin film layer that can be selectively etched with the coil insulating layer and the base layer on the lower core protrusion of the track width dimension at the same time as the protrusion formation, and to form a through hole to the coil insulating film. This is achieved by performing ion etching up to part of the new thin film layer, and then removing the new thin film layer using a selective etching method such as reactive ion etching.

[Operation] Since the new thin film layer on the newly provided lower core protrusion is patterned at the same time as the protrusion, no misalignment with the protrusion occurs. Further, the width of the through hole provided in the coil insulating layer is defined by this thin film layer. Therefore, there is no track misalignment between the protrusion and the through hole, that is, the lower core and the upper core.

Further, although the thin film layer is required to be a material that can be selectively etched, it is removed during the process, and the final constituent material is not limited in etching selectivity and can be of any material composition.

〔Example〕

Embodiments of the method for manufacturing a thin film magnetic head according to the present invention will be described below with reference to the drawings.

FIG. 1 is a process explanatory diagram of a method for manufacturing a thin-film magnetic head according to an embodiment of the present invention, in which the left side of the figure is a sliding surface, the right side is a cross-sectional view in the magnetic path direction, and the lower magnetic core is nonmagnetic. This is a thin film magnetic head embedded in a substrate and having a structure in which coils are formed in protrusions provided at the front and rear of a lower magnetic core.

In the figure, 1 is a non-magnetic substrate, 2 is a lower magnetic core embedded in the substrate, 2a and 2b are protrusions provided on the front and rear parts of the lower magnetic core, 41° and 42 are coil insulating layers, 6a, 6b is a through-hole in the front and rear parts provided in the coil insulating layer.

7 is a gap material, and 8 is an upper magnetic core.

Hereinafter, steps (a) to (i) will be explained.

(a) A groove is dug in the non-magnetic substrate 1 using a dicing saw, ion etching, etc., a magnetic film of CoNbZr, FeAlSi, etc. is formed by sputtering, and the groove is flattened by abrasion.

(b) A thin film layer 3 is formed by depositing Sin to a predetermined thickness by sputtering.

(c) The thin film layer 3 made of Sin and the lower magnetic core 2 are simultaneously patterned by ion etching.

As a result, the protrusion 2a on the front part, the protrusion 2b on the rear part, and the thin film pattern 3a s3b on these are created, and the protrusion 2a and the thin film pattern 3a finally become the lower core width and the upper core width, and define the track width. do.

(d) As the first coil insulating layer, Sin and selective
Soching possible A1. An insulating film 41 of O, \SiO*-MgO, etc. is formed by sputtering.

(e) After forming the coil conductor 5 made of Cr/Cu/Cr (Cr; adhesive layer), the same material as the first coil insulating film is formed by sputtering to form the second coil insulating layer 42.

(f) The second coil insulating layer 42 is made flat by an etch-back method, polishing, or the like. The film thickness of the second coil insulating layer 42 is between the thin film pattern 3a (3b) and the lower magnetic core protrusion 2a (2b).
be thicker than the combined height of

(g) Lower magnetic core protrusion 2a on coil insulating layer 41, 42
.

Through holes 6a and 6b are formed by ion etching in alignment with 2b. Ion etching impairs the flatness of the etched surface and causes head performance deterioration due to azimuth loss, so the etching process ends with the thin film patterns 3a and 3b remaining at a predetermined thickness (h) The remaining thin film patterns 3a and 3b are removed. Etching is performed by reactive ion etching using CF or the like to complete through holes 6a and 8b.

(i) After forming a gap material 7 of Cr, Altos, Sift-MgO based insulating material, etc., the same core material as the lower magnetic core is deposited by sputtering and etched to form the upper magnetic core 8. Thereafter, the head is completed by forming a protective film, forming a chip, assembling process, etc.

According to the above manufacturing method, it is possible to eliminate misalignment between the through hole 6a and the protrusion 2a. Next, the reason will be explained with reference to FIG.

FIG. 2 is a sectional view corresponding to the sliding surface for explaining steps (f) to (h) in FIG. 1. However, first,
The second coil insulating layers 41 and 42 collectively form the coil insulating layer 4.
And so.

In the figure, a coil insulating layer 4 (
When a through hole is provided in the film thickness T), the thin film pattern 3a
If the amount of positional deviation from the
is the amount of positional deviation between the through hole and the protrusion. However, in this embodiment, the thin film of the thin film pattern 3a is t
Etching is further carried out by ion etching until it becomes less than o. By this etching, the through hole changes from a dashed line to a dotted line. After that, if the remaining thin film pattern 3a (film thickness to) is removed by reactive ion etching with etching selectivity, the bottom part of the through hole will be removed. Although there is a slight part with an almost vertical taper, no misalignment between the through hole and the protrusion occurs at all.

In this manner, the present invention absorbs the amount of in-plane positional deviation in the film thickness direction. Here, the relationship between the film thickness t8 of the thin film pattern 3a and the absorption displacement amount Δ2 will be explained in more detail with reference to FIG.

FIG. 3 is a graph showing the relationship between the film thickness of the thin film pattern in FIG. 2 and the amount of shift that can be absorbed, under the following conditions.

The through hole height is the same as the conventional one, i.e. T+t□
=10 (μm) The through-hole taper angle α was α=45(′), and the film thickness to of the thin film pattern 3a left by ion etching was set to 1 μm in the film thickness distribution within the substrate.

From the figure, it can be seen that t8 should be set to 4 μm in order to absorb the maximum value of 3 μm that may shift in the prior art described above. However, in this example, the film thickness etched by ion etching is t! Because it is thinner, the maximum possible positional deviation is smaller than before.
In reality, t8 may be thinner than 4 μm.

In the embodiment described above, the coil is inserted into the lower core, the gap material is formed immediately before the formation of the upper core, and the thin film layer 3a is made of Sin. However, the present invention is not limited to these structures and materials. It's not something you can do.

Further, in the above embodiment, the thin film layer 3a and the lower magnetic core tip 2a were formed at the same time, but even if the thin film layer 3a is formed after the lower magnetic core tip is formed, the alignment accuracy is better than in the past. Become.

[Effects of the Invention] As explained above, according to the present invention, there is no misalignment between the lower core protrusion formed in the track width dimension and the through hole provided in the coil insulating layer. It is possible to stably produce a magnetic head with no core track deviation.

In addition, the restriction that the coil insulating film can be selectively etched, which was previously required, is eliminated, and any material can be used. It is possible to provide a thin-film magnetic head that does not require a thin-film magnetic head.

[Brief explanation of drawings]

FIG. 1 is a manufacturing process diagram explaining one embodiment of the present invention, and FIG.
The figure is a cross-sectional view of the sliding part for explaining the main part of the process in Figure 1, Figure 3 is a graph showing the relationship between the amount of in-plane positional deviation absorbed by the present invention and the thin film layer, The figure is an explanatory view of an example of a head sliding surface manufactured by a conventional technique. 1... Non-magnetic substrate 2... Lower core 2a...
Lower magnetic core front part protrusion 3a...Front part thin film pattern 4, 41, 42...Coil insulating layer 6a...Front core part through hole 8...Upper magnetic core. 〒Fig.

Claims (1)

[Claims] 1. On a non-magnetic substrate 1, a lower magnetic core 2, a gap material 7,
A thin film magnetic head formed by laminating a coil conductor 5, a coil insulating film 4, an upper magnetic core 8, etc., in which the lower magnetic core tip 2a is processed to have a track width dimension, and the lower magnetic core tip 2a is aligned with the lower magnetic core tip 2a. In a method for manufacturing a thin film magnetic head having a structure in which the track width is regulated by a through hole 6a provided in the coil insulating film 4 formed together, the step of forming the through hole 6a includes the step of forming the lower magnetic core tip 2a. A step of providing a thin film layer 3a having a track width dimension thereon, a step of forming a coil conductor 5, a step of forming a coil insulating portion 4, and a step of forming a through hole in the coil insulating film portion on the thin film layer 3a by ion etching. 6a and etching the thin film layer 3a until it reaches a predetermined thickness; and etching and removing the remainder of the thin film layer 3a by reactive ion etching. Production method. 2. The method of manufacturing a thin film magnetic head according to claim 1, wherein the thin film layer 3 is formed at the same time as the lower magnetic core tip 2a.