JPS63121110A - Manufacture of thin film magnetic head - Google Patents

Abstract

PURPOSE:To form a second coil in a first coil, to simultaneously flatten the upper part of coils and to prevent a step in the coil from being generated, by removing photoresist and a conductor thin film with their equal etching rates. CONSTITUTION:After the first coil 24 is formed, the conductor thin film 26 is formed over entire plane of a substrate setting a second insulating layer 25 as an intermediate layer, and after that, the photoresist 27 is coated. The photoresist is fluid having viscosity of 30-200cp, and a coating film absorbs the step of a lower part less than that, and its surface is almost flattened uniformly. After heat curing is applied on it, etching is applied on the conductor film 26 and the photoresist 27 with their equal etching condition. In such a way, the second coil 28 is formed in such structure that the conductor thin film is embedded in the recessed part of a coil space in the first coil 24, and the step is scarcely formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a thin film magnetic head compatible with higher recording densities.

Conventional technology In recent years in the field of magnetic recording technology, thin-film magnetic heads that make full use of thin-film formation technology and IJ sogelafy technology have been developed as magnetic heads that can accommodate the shortening of track widths and multi-tracking as track densities have improved. It is becoming widely used. Figure 4 (&) is a plan view showing a conventional ring-type thin film head, and Figure 4 (b) is the I of Figure 4 (IL).
This is a sectional view taken along the line L-&', and has a structure in which a coil is wound many times around a ring-shaped core having a gap. The conventional method for manufacturing a thin film magnetic head will be explained below using FIGS. 4e) and 4(b). That is, the first insulating layer 42 is formed on the mirror-polished magnetic substrate 41. Next, Mu! Alternatively, a metal thin film such as an Or base layer is deposited and patterned into the coil 43 by photolithography. After this, a second insulating layer 44 is formed, and a front gap portion 46 and a back gap portion 46 are patterned.

After this, Ni-Fe becomes the upper magnetic core 47.

A ferromagnetic metal thin film such as Fe-me 2-81 is deposited and formed into a predetermined shape. Finally, a protective layer (not shown) and a protective substrate (not shown) are formed, and the tape sliding surface 48 is polished to complete the thin film magnetic head. Reference numerals 49 and 50 are connection terminals for connection with an external circuit, and the insulating layer formed thereon is removed.

Problems to be Solved by the Invention In the conventional thin film magnetic head manufacturing method described above, the thin film formed after the coil formation directly reflects the shape of the lower coil, and has a step difference as shown in FIG. 4(b). It becomes a thin film. In particular, the level difference that occurs in the upper magnetic core 47 has been a factor that greatly deteriorates the magnetic properties of the upper magnetic core. In other words, surface magnetic charges are generated near the stepped portion, and the resulting demagnetizing field effect causes a decrease in magnetic permeability.
The thickness of the ferromagnetic thin film is thin in the diagonal portion of the step, and during recording, there is a phenomenon where the diagonal portion of the step becomes magnetically saturated.For this reason, the signal magnetic field leaking at the front gap portion 45 causes the magnetic medium to reach the saturation level. This had the disadvantage that it could not reach the strength that would allow recording up to 1000 yen, resulting in extremely poor magnetic efficiency.

Further, when patterning the coils by photolithography technology, it is necessary to set the coil spacing to 3 to 6 μm or more in order to prevent short circuits between the coils. Therefore, if the number of windings of the coil is increased in an attempt to reduce the recording current flowing through the coil and reduce current consumption, the magnetic path of the upper magnetic core formed at the top of the coil becomes longer, and the recording magnetic field is shifted to the front. There was a drawback that the initial purpose could not be achieved because it leaked to other places before reaching the gap. In order to avoid this problem, attempts have been made to form coils in multiple layers, such as two or three layers, but these have the drawbacks of increasing the step difference caused by the coils mentioned above, and further decreasing magnetic efficiency. was there.

In view of the above-mentioned conventional thin film magnetic head manufacturing method, the present invention eliminates the step shape of the coil in the upper magnetic core, and also improves recording efficiency by making it possible to wind the coil multiple times by setting the coil interval to 1 μm or less. The present invention relates to a thin film magnetic head manufacturing method for providing a high quality thin film magnetic head.

Means for Solving the Problems In order to achieve the above object, in the magnetic head manufacturing method of the present invention, a first insulating layer and a first insulating layer are first formed on a magnetic substrate.
A conductive thin film is then formed on the entire surface of the substrate by vapor deposition or sputtering, using the second insulating layer as an intermediate layer. Next, a photoresist is applied on the conductor thin film, and the photoresist and the conductor thin film are removed at the same etching rate, and a second coil is formed just between the first coil and the second conductor thin film.
It is characterized by the fact that the upper part of the coil is flat, and there is no step difference in the coil.

As described above, in the thin film magnetic head manufacturing method of the present invention, after forming the first coil, a conductive thin film is formed on the entire surface of the substrate using the second insulating layer as an intermediate layer, and then a photoresist is applied. do. Photoresist has a viscosity so c
With a fluid of p~2000p, the coating film absorbs the level difference below it, and the surface becomes a substantially uniform plane. After thermally curing the conductor thin film and the photoresist, the conductor thin film and the photoresist are etched under these same etching rate conditions, so that the conductor thin film is embedded in the recessed portion between the coils in the first coil, and the second coil is recessed. is formed, and there are almost no steps.

Therefore, no step is formed in the upper magnetic core formed above the coil, and the problem of decrease in magnetic permeability due to the demagnetizing field effect caused by the step is solved. In addition, the film thickness of the upper magnetic core at the top of the coil is constant, and there is no particularly thin part, so there is no magnetic saturation in the middle of the upper magnetic core, and the recording magnetic flux is efficiently guided to the front gap. Become.

In addition, the second insulating layer that electrically insulates the first coil and the second coil has a thickness of 1 μm or less, and the coil spacing is extremely small and dense compared to conventional ones. By winding a large number of turns, it is possible to reduce power consumption without reducing recording efficiency.

EXAMPLE Hereinafter, an example of the method for manufacturing a thin film magnetic head of the present invention will be described with reference to FIGS. 1 and 2 (IL) to (e). Figures 1 and 2 (2L) to (6) are shown in Figure 4 (b).
) shows a cross-section of the main part of the thin-film magnetic head.

First, as shown in FIG. 2(a), a mu e205 insulating film 22 is formed as a first insulating layer on a mirror-polished ferromagnetic substrate 21.
is formed. At this time, the back gap portion 23 is
The third insulating film 22 is removed by a lift-off method. Further, the film thickness of the mu E203 insulating film 22 is formed to be exactly equal to the gap length. Next, as shown in FIG. 2(b), a conductor thin film such as a MuU thin film on an Or base is formed to serve as a coil conductor, and is patterned by photolithography to form the first coil 24. After this, Figure 2 (
As shown in 0), S with a film thickness of about 0.5 μm is used as the second insulating layer.
An iO□ insulating film 26 is formed and patterned into a predetermined shape. Next, as shown in FIG. 2(d), a conductive thin film 26 similar to the material of the second coil is deposited over the entire surface of the substrate.

A cyclized rubber-bisamide photoresist 27 is spin-coded on the conductor thin film 2e and then thermally cured. The photoresist 27 after thermosetting absorbs the irregularities of the first coil, and the photoresist on the coil has a substantially uniform surface.

The lower the viscosity of the photoresist on the coil, and the smaller the pitch interval of the first coil, the more uniform the surface tended to be. Then, by etching the photoresist and the MuU thin film at the same etching rate until the convex portion of the second insulating layer 25 is exposed, the first coil is etched as shown in FIG. 2(6). The second coil 2B is formed to have a structure embedded in the recess between the coils.

The coil 27 is formed into a buried shape.

As the etching method, an ion scilling method was used in which ionized chromium ions are accelerated and etched by hitting the substrate. In the ion scilling method, the etching rate varies depending on the angle of incidence of accelerated MR ions on the substrate, and by appropriately selecting the ion incidence angle, different materials can be etched at the same etching rate.

In Figure 3, M shows the relationship between the etching rate of the gold thin film and B the cyclized rubber-bisazide photoresist and the M r ion incidence angle. In this case, the incident angle of the equal etching rate is 75 degrees. It is.

Thereafter, the second insulating layer 26 on the connecting portion (not shown) of the first coil 24 is formed using photolithography technology so that the first coil 24 and the second coil 28 are connected in series. After removal, the first coil 24 and the second coil 28
A conductive thin film (not shown) is formed to connect the two.

Thereafter, a SiO□ insulating film 30 is formed as a third insulating layer 3° on the second coil 28, and the front gap portion 29
, the excess 5in2 insulating film on the back gap part 23 is removed by etching, the upper magnetic core 31 is formed on top of this, and finally a protective layer (not shown) is formed, and a protective substrate (not shown) is bonded. The tape sliding surface 20 is polished,
A thin film magnetic head as shown in FIG. 1 is completed.

In this example, the ion silling method was used to eliminate the coil step difference by etching, but there are also plasma etching methods in which the sample is placed in a plasma of a reactive gas, and etching is performed in a plasma of a reactive gas. A reactive plasma etching method, in which a sample is placed on the substrate and etched, can be used.

Further, in the present invention, it is clear that a plurality of the first coil and the second coil may be formed as basic units.

Effects of the Invention According to the method for manufacturing a thin film magnetic head of the present invention, there is no step caused by the coil in the upper magnetic core, and the thickness of the core is constant. Therefore, there is no phenomenon of decrease in magnetic permeability due to the demagnetizing field effect mentioned above, there is no part where the film thickness of the magnetic core becomes extremely thin, and the signal magnetic flux generated by the coil does not reach magnetic saturation before reaching the front gap. This has the effect of providing a thin film magnetic head with extremely high magnetic efficiency at a low cost.

Further, the film thickness of the Sio2 insulating film as the second insulating layer that electrically insulates the first coil and the second coil is 0.5 μm.
m is sufficient, and the coil can be formed extremely densely compared to conventional ones. For this reason, even if the coil is wound many times, the magnetic path length of the upper magnetic core does not increase, and therefore,
The leakage of recording magnetic field is extremely small and has the effect of providing a thin film magnetic head with high magnetic efficiency at a low cost.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view of a main part of a thin film magnetic head manufactured by the method for manufacturing a thin film magnetic head according to the present invention. FIG. 2 is a cross-sectional view for explaining one embodiment of the method for manufacturing a thin film magnetic head according to the present invention. FIG. 3 shows the relationship between the etching rate of gold and cyclized rubber-bisazide photoresists by the ion shilling method and the incident angle of the ion ferromagnetic substrate, 22...・
・First insulating layer, 24...First coil, 26
...Second insulating layer, 28...Second coil, 30...Third insulating layer, 31...
Upper magnetic core. 22- First insulating layer 23- Bag gap part 24- 1st ty) Fill 25- Second insulating layer 3I- Part Sulfuric core Figure 1 Figure 2 Figure 3 0102030 #50667148ρA Bi-in elbow angle 7
jj (skin)

Claims (1)

[Claims] forming a first insulating layer on a magnetic substrate, forming a first conductive material on the first insulating layer, patterning it into a coil shape to form a first coil, and forming a first conductive material on the first coil; After forming a second insulating layer and forming a second conductive material on the second insulating layer, a photoresist is applied, the photoresist and the second conductive material are removed at an equal etching rate, and a second conductive material is formed on the second insulating layer. A second coil is formed in the recess formed by the lower coil spacing part of the insulating layer, and the first coil and the second coil are connected in series,
A method for manufacturing a thin-film magnetic head, characterized in that a third insulating layer and an upper magnetic core are then formed.