JPS6227445B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing electrical windings for thin film magnetic heads.

In recent years, thin film magnetic heads (also referred to as magnetic conversion heads for magnetic recording) have come to be formed by applying integrated circuit formation techniques. A thin film magnetic head is, for example, as shown in FIG. 1, in which magnetic bodies 2 and 3 formed on a base 1 form a magnetic path having a magnetic gap 6 at the tip of the head. By intersecting the electric winding with the magnetic path, electromagnetic conversion is effected between the magnetic path and the electric winding. That is, when a current is applied between both terminals 5a and 5b of the electric winding, a strong magnetic field is generated in the magnetic gap 6, and a recording medium (not shown) placed near the magnetic gap 6 is magnetized by this magnetic field. . On the other hand, by moving a reversely magnetized recording medium near the magnetic gap 6, a change in magnetic flux occurs in the magnetic field through the magnetic gap 6, an electromotive force is generated in the electric winding, and an electric signal is generated between the terminals 5a and 5b. is obtained.

Forming a magnetic head that operates as described above from a thin film provides the following advantages.

(i) By forming the magnetic material 3 by photolithography, the width of the magnetic gap in the y-direction of FIG. 1 can be miniaturized with good reproducibility, and the recording track density can therefore be increased.

(ii) For example, thin films of permalloy alloy used as the magnetic bodies 2 and 3 do not have a decrease in magnetic permeability up to about 30 to 50 MHz. Therefore, compared to conventional magnetic heads made with ferrite cores, it is superior in high frequency operation and can increase linear recording density.

However, there are restrictions in constructing the magnetic head with a thin film, and these points will be explained in detail below.

Figure 2 shows a cross-section of the main part of the thin film head compared to Figure 1. When recording information, each piece of winding 4a, 4b, 4c, 4d is shown in the same direction penetrating the plane of the paper. When a current is applied, magnetic lines of force as shown by the broken lines in FIG. 2 are generated. These magnetic lines of force also leak to the winding window 7 surrounded by the magnetic bodies 2 and 3.
These lines of magnetic force accumulate at the rear end of the magnetic path (left end in Figure 2). Therefore, this rear end may bring about magnetic saturation in the material constituting the magnetic path, making it impossible to generate a sufficiently strong magnetic field in the magnetic gap 6.

In order to prevent this phenomenon, the height of the winding window 7
In addition to making ha sufficiently large, the width L in the depth direction of the winding window 7 must be made small.According to the research of the present inventors, one example of this is setting ha to 8μ.
An example of this is to set L to 100 μm or less, where m is 100 μm or less.

On the other hand, in order to increase the sensitivity of such a magnetic head (reducing the amplitude of the current required to record information and increasing the signal voltage obtained by reproducing information), it is necessary to increase the number of turns of the winding 4 that intersects with the magnetic path. It is necessary to choose a large number. However, since the width L in the depth direction is restricted as described above, it has been difficult to increase the number in terms of microfabrication technology. That is, as shown in FIG. 3, when the conductor 10 deposited on the base 1 is chemically etched into a desired shape using the photoresist 11, in an ideal state, the etching is concentrically formed from the edge of the photoresist 11. proceed. Therefore, if the opening width of the photoresist 11 is D, then the conductor 10 with the thickness t
When etched, the average width (groove width) of the removed portion of the conductor 10 is D+1/2πr. conductor 10
When the thickness t is large, the amount to be etched increases, and the opening width D must be increased in order to circulate and remove the etching liquid whose performance has been reduced due to etching. Therefore, the thickness of the conductor 10 is 2.8 μm, and the opening width D
If 2.8 μm, the groove width of the conductor 10 will be about 7.0 μm.

On the other hand, the current given to winding 4 is 100 to 200 mA
In order to avoid disconnection due to temperature rise in the winding 4, the current density must be kept below about 5×10 ⁵ A/cm ² , and therefore the cross-sectional area of each piece of the winding 4 is at least It must be at least 2×10 ^-7 cm ² (20 μm ² ). If the thickness t of the conductor 10 forming the winding 4 is 2.8 μm, the width of each piece of the winding 4 is 7.1 μm.
If the number of turns is 8, the winding is 4.
The depth width is approximately 104 μm.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing an electric winding for a thin film magnetic head, which improves the drawbacks of the prior art described above and improves the degree of completeness of the electric winding.

The gist of the present invention is a method of manufacturing an electrical winding for a thin film magnetic head, which is characterized by including the following series of steps.

(i) After depositing a first conductive film, a first insulating film is formed to partially cover the first conductive film, and then a first insulating film of the first conductive film is formed. (ii) forming a plurality of first conductor parts whose upper parts are covered with a first insulating film by removing the parts not covered with the film; (ii) forming a second conductor part on the side of the first conductor part; (iii) depositing a second conductor portion in the gaps between the plurality of first conductor portions covered with the first insulator film and the second insulator film; iv) removing the first insulator film and the second conductor portion deposited thereon; and (v) depositing a third insulator over the first and second conductor portions. A process of forming a film.

Embodiments of the present invention will be described below with reference to FIGS. 4 to 6.

FIG. 4 shows a series of steps in the method of manufacturing an electric winding for a thin film magnetic head according to the present invention.
In FIG. 4(i), a plurality of photoresists 15 are formed in a predetermined shape on a first conductive film formed by a known method such as vacuum evaporation, sputtering, or electroplating, and then a chemical etching method or a sputter etching method is used. Alternatively, the plurality of first conductor portions 16 are formed by known means such as ion milling.

Next, in FIG. 4(ii), a second insulating film 17 is formed on the side end portion of the first conductor portion 16 by an electrostatic or electrochemical method while leaving the photoresist 15.

Further, in FIG. 4(iii), a plurality of second conductor portions 18 are deposited in the gaps between the plurality of first conductor portions 16 by vacuum deposition or sputtering.

Next, in FIG. 4(iv), when the photoresist 15 is dissolved and removed, the second conductor portion 18a deposited on the photoresist 15 is removed together with the photoresist 15. At this time, the previously formed first conductor portion 16 and the newly formed second conductor portion 18 are electrically insulated from each other by the second insulating film 17.

Further, in FIG. 4(v), after both ends of the second conductor portion 18 are formed into a desired shape by chemical etching or the like, a third conductor portion is formed on the first conductor portion 16 and the second conductor portion 18. An insulator film 20 is deposited to electrically insulate them from each other to obtain the electrical winding of the present invention.

Next, as shown in FIG. 5, two conductor portions (hereinafter referred to as winding portions) 16 and 18 are electrically connected to obtain one complete electrical winding. That is, the fifth
In the figure, by forming connection windows 21a to 21d by removing a predetermined portion of an electrical insulator 20 (not shown) and then forming third conductor films 22a and 22b, 23a and 23b are used as both terminals, and 23c is An electrical winding with a midpoint terminal is obtained.

As described above, according to the present invention, since the pieces adjacent to the winding are arranged at intervals equal to the thickness of the insulating film 17, the degree of completeness of the winding increases, and when the number of turns of the winding is the same, The depth width L of the winding can be shortened, and when the depth width L is the same, the number of windings can be increased compared to the conventional method.

For example, the thickness of the winding portions 16 and 18 is 2.8μ.
m, the average width is 7.1 μm, and the thickness of the insulator film 17 is 1 μm. In order to obtain 8 turns, the depth width L of the winding was approximately 104 μm in the conventional example, whereas in the present invention, the depth L of the winding was approximately 104 μm. The depth width L of the line is 66 μm,
Also, even if the number of turns is 12, the depth width L of the winding is approximately 98μ.
It was m. That is, the method of the present invention was able to increase the degree of completeness of the windings by approximately 1.5 times.

Further, according to the method of the present invention, the second winding portion 1
Since the shape of 8 is determined by the photoresist film forming the first winding portion 16, the positional relationship between the first winding portion 16 and the second winding portion 18 is determined with high precision. has advantages.

Furthermore, as an advantage of the present invention, as is clear from FIG. 4(v), since the upper surfaces of the formed winding portions 16 and 18 are flat, similar steps can be repeated to
Fourth, even more winding sections can be stacked. At this time, as shown in Figure 5, the first and second winding parts are wound from the outer circumference to the inner circumference, and the third and fourth winding parts are wound from the inner circumference to the outer circumference. conductors 22a and 22b
It is also possible to make it unnecessary.

A method for forming the insulator film 17 on the side end portion of the winding portion 16 shown in FIG. 4(ii) will be described below.

The first method is an electrochemical method, in particular an anodization method, which is used to form a good quality water-insoluble insulator when the material of the first conductor, which becomes the winding section 16, is oxidized to an oxide. Limited to things that make up the body. Examples of the material for such a first conductor include aluminum, tantalum, and zirconium, and the following description will be made using aluminum as an example. When aluminum is immersed in an aqueous solution of dilute sulfuric acid, oxalic acid, chromic acid, etc., a noble metal such as platinum is used as the cathode, and aluminum is used as the anode, and a current of ^about 0.3A/dm2 is applied, a thin alumina layer is formed on the aluminum surface. be done. This method produces very few pinholes, so even a thin film of 1 μm or less functions well as an insulator film. According to the research of the present inventors, if a photoresist with the trade name OMR83 is used and anodized with sulfuric acid or oxalic acid aqueous solution, an alumina insulating film can be formed only on the exposed parts without causing deterioration of the photoresist. be able to.

The second method is electrophoresis. In this method, a fine powder of glass or the like is suspended in a liquid such as isopropyl alcohol, the object to be adhered is used as a cathode, platinum or the like is used as an anode, and a voltage of 100 to 500 V is applied between the two electrodes. Powder such as glass is attracted by the electrostatic field and sticks to the surface of the conductor. Then, after removing it from the solvent solution and drying it, the fine powder of glass or the like is sintered at a temperature of 300 to 400°C to obtain the desired insulating film 17. In this method, the above photoresists cannot be used, and a product name with higher heat resistance is used.
It is necessary to use an organic resin called PIQ or an inorganic substance called SiO ₂ .

As a third method, ion vapor deposition or ion sputtering methods can be used in which a vapor of SiO ₂ , Si ₃ N ₄ or alumina is charged or ionized in a vacuum and then attracted and adsorbed by an electrostatic field.

In the above explanation, photoresist 1 is used as the electrical insulating film.
Although an example using No. 5 has been shown, it is clear that the electrical insulating film may be a composite of two or more kinds of films. For example, the conductor portion 18a formed on the photoresist 15 in the step shown in FIG. Sometimes they become unified. In such a case, it is preferable to form a layer 15a of PIQ, which is the above-mentioned insulating organic resin, on the conductor 16, as shown in FIG. 6, and further form a photoresist 15 thereon. Also, instead of photoresist 15
A PIQ layer 15a can also be formed.

As detailed above, according to the method of the present invention, the completeness of the winding can be increased, the depth of the winding can be shortened when the number of turns of the winding is the same, and the depth of the winding can be shortened when the number of turns of the winding is the same. In some cases a higher number of turns could be achieved.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a thin film magnetic head, Fig. 2 is a sectional view taken along the line - - in Fig. 1, Fig. 3 is a sectional view showing a conductor film chemically etched using photoresist, and Fig. 4. 5 is a process diagram showing the method of manufacturing an electric winding for a thin film magnetic head according to the present invention, and FIG. FIG. 6 is a diagram illustrating an electrical winding, the first conductor portion being covered on top by a two-layer insulating film. 15...first insulator film (photoresist), 1
5a... PIQ, 16... First conductor (winding) part, 17... Second insulator film, 18... Second conductor (winding) part, 18a... Second conductor part, 2
0...Third insulator film.

Claims (1)

[Scope of Claims] 1. A method for manufacturing an electric winding for a thin film magnetic head, which comprises the following series of steps. (i) After depositing the first conductive film, the conductive film is covered with a first insulating film so that a predetermined circuit is formed by the first conductive film, and then the first (ii) removing a portion of the first conductor film that is not covered with the insulator film to form a first conductor portion whose upper part is covered with the first insulator film; (iii) forming a second insulator film on the side of the conductor portion; (iii) forming a second conductor in the gap between the first conductor portion covered with the first insulator film and the second insulator film; (iv) removing the first insulating film and the second conductor portion deposited thereon; and (v) removing the first conductor portion and the second conductor portion. A step of forming a third insulator film thereon. 2. The method according to claim 1, wherein the first conductor is made of a material capable of forming an electrically insulating film on its surface by anodizing, and the step (ii) is carried out by anodizing. A method of manufacturing an electric winding for a thin film magnetic head. 3. The method of manufacturing an electric winding for a thin film magnetic head according to claim 1, wherein the step (ii) is carried out by electrophoresis. 4. The method of manufacturing an electric winding for a thin film magnetic head according to claim 1, wherein the step (ii) is carried out by ion deposition or ion sputtering.