JPS62165718A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To prevent cracks from being caused by forming dummy coils to an inner and/or outer circumference of a conductor coil except the uppermost layer so as to decrease the step difference at the position for making flatness thereby reducing the film thickness of a coating film for flatness forming. CONSTITUTION:In forming a two layer six turn thin film magnetic head, a lower magnetic core 12 is formed on a base 11 at first and then an insulation film 13 is formed. A conductor film is worked to a prescribed shape thereupon to form a 1st layer three turn thin film conductor coil 14 and to form dummy coils 14a-14e at the same time by the same material and manufacture method. An insulation film 17 is formed on them and a film 18 for flatness forming on the film 17. A 2nd layer three turn thin film conductor coil 19, and insulation film 20 and a film 21 for flatness forming are provided by the similar procedure. Thus, the film thickness of the 2nd layer film 21 at the inner and outer circumference of the coil 14 is reduce in this way, and cracks at sintering are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thin film magnetic head, and particularly to a thin film magnetic head using a multilayer conductor coil.

(Conventional technology and its problems) In recent years, it has become popular for high-density recording because it is easier to narrow tracks, narrow gaps, and increase the number of elements compared to magnetic heads made by processing soft magnetic bulk materials. Thin film magnetic heads are considered important as heads.

By the way, in order to achieve high-density recording in this thin film magnetic head, it is required to reduce the current by narrowing the track, narrowing the gap, and using multi-turns (multiple turns). In addition, in multi-track magnetic heads, in order to reduce the arrangement space of conductor coils, and in -track magnetic heads, in order to reduce the current due to the above-mentioned multi-turn structure, a lower magnetic core and an upper magnetic core made of a soft magnetic thin film are used, respectively. It is preferable to laminate a plurality of colored conductor coils between the cores to form a multilayer conductor coil shape. When such a multilayer coil shape is adopted, it is very important to flatten the level difference caused by the conductor coil.

In other words, if the level difference caused by the lower layer coil is not sufficiently flattened, the pattern accuracy of the upper fine coil may deteriorate, and the magnetic properties such as magnetic permeability, saturation magnetic east density, and coercive force of the upper magnetic core may deteriorate. A problem arises. In the future, as coils become smaller and more highly integrated, it is thought that the influence of flattening on the characteristics of thin-film magnetic heads will become greater.

Incidentally, as a conventional planarization method, a lift-off method or a method of applying a multifunctional insulating material such as polyimide or a coating type SiO, etc. for planarization is known. Among them, coating type Sin is easy to apply, and although it contains some organic properties, it is essentially inorganic, so it is highly stable, and it is said that dry processes such as plasma etching can be used. This is a very useful method with many advantages.

FIGS. 4 and 5 show a conventional two-layer, six-turn thin film magnetic head using coated SiOt for planarization. Fourth
The figure is a schematic plan view of the 1FF 1/3 turn conductor coil portion shown with the second layer coil removed, and FIG. 5 is a schematic enlarged sectional view taken along the line ■-■ in FIG. 4. In both figures, ■ is a substrate, on which a first layer of thin film conductive coil 4 is formed via a lower magnetic core 2 and an insulating film 3, and on this conductive coil 4 an insulating film 5 is formed. is formed, and a planarizing Si film 6 is coated on the insulating film 5. Further, on the coating type 5iOtnlAG, a second layer conductor coil 7, an insulating film 8, and a coating type 5ift film 9 for planarization are provided in the same manner as the first layer, and then the S! An upper magnetic core (not shown) is formed on the 01 film 9.

By the way, in the illustrated magnetic head, the 15th conductor coil 4 and the second layer conductor coil 7 are located at the inner and outer circumferential portions of the second layer conductor coil 7 indicated by arrows b1 and b in FIG. Since the patterns of are almost overlapping, 1st layer coating type S
tO! Although this has been alleviated to some extent, there will still be a difference in thickness equal to the thickness of the two layers of coil 4 and coil 7. Therefore, the second coating type 5iOx9 is applied over a wide area and in a thickness of X at this location. Therefore, a situation has arisen in which cracks are likely to occur in the second layer SiO2 film 9 due to volume shrinkage during firing or stress due to a tensile load applied from other films. Such a rack adversely affects the stability and reliability of the thin film magnetic head.

In order to reduce the frequency of cracks, a method is known in which the coating type SIO 2 contains an organic component, but if the organic component increases, the adhering force of the 5iOt film 9 to the insulating film 8 will decrease, and the structure This is not necessarily a useful method because it causes problems with stability.

(Means for Solving the Problems) The present invention has been made to solve the above-mentioned problems, and specifically, the present invention is directed to the inner circumference and/or outer circumference of the conductor coil in each layer other than the top layer. The present invention is characterized in that a dummy coil is formed in a portion to reduce the thickness of the coating film in that portion.

In addition, when the conductor coil has three or more layers, it is preferable that the dummy coil is provided in each layer other than the top layer, and that the dummy coil is extended to a position further away from the coil in the direction of one ball in the lower layer.

(Example) Next, the present invention will be described in detail with reference to the accompanying drawings.
In Figures 1 to 3, the dummy coil of the present invention is added to the conventional conductor coil! A track thin film magnetic head is shown. The structure and manufacturing method of this magnetic head will be described below. Substrates made of alumina, ferrite, glass, etc. with excellent wear resistance
A soft magnetic thin film such as Fe-Al-5LN i -re or Co-based amorphous is laminated thereon by sputtering, electron beam evaporation, or the like to form the lower magnetic core 12 .

Next, plasma CVD (Chemical Vap
or deposition) method, sputtering method, electron beam evaporation method, etc. ．． 5LN4, Al
An insulating film 13 made of, for example, to is formed. Furthermore, Cu,
A conductive film of Al5Au, Δg, etc. is laminated by sputtering, vapor deposition, plating, etc., and then the conductive film is processed into a predetermined shape by ion milling, sputter etching, etc. to form a thin film with 3 turns of Iff. A shaped conductor coil 14 is formed. At the same time, dummy coils 14a to 14 are made of the same material and manufacturing method as the conductor coil 4.
form e.

Next, 5ift, AItol, Si,
Insulating film made of N4 etc.! form 7.

Further, a coating type 5iOy is applied on the insulating film 17 to form a first layer of 5iOz film 18 for flattening, and the conductor coil 14 is coated with a coating type 5iOy.
Also, the difference in level between the upper surface of each dummy coil 14a to 14e and the substrate 11 is absorbed. In this case, the flat portion 18a of the coating type 5iOt film 1B is extended from the inner and outer peripheries of the conductor coil 4 along the dummy coils 14a=14e.

Hereinafter, the above first layer 5iOt film 8
A second layer of three-turn thin film conductor coil 19, an insulating film 20, and a second layer of 5iOzEt 21 for planarization are sequentially provided on top. Thereafter, the 5iOz film 21 of the front gap portion 15 is etched by a plasma edging method, a reactive ion etching method, etc., and after the magnetic gap layer 22 is laminated, the insulating layer of the back core connection portion is etched. Then, the process of forming the upper magnetic core 23 made of a soft magnetic thin film continues.

In the above manufacturing process, by extending the flat portion 18a of the first color film 18 in the radial direction along the dummy coils 14a to 14c, the conductor at the inner and outer circumferential portions of one second layer conductor coil is The level difference between the upper surface of the coil 19 and the first layer Sin and the film 18 is reduced. Therefore, as shown by arrow b3 in FIG. 2, for example, the thickness of the second layer 5io2 film 2I at the inner and outer circumferential portions of the conductor coil 19 is made smaller than the conventional thickness (see arrow 8 in FIG. 5). By making it thinner, the difference in level between the conductive coil 19, the first layer of Sin, and the film 18 can be gently flattened. In this way, the conductor coil 14
Since it is possible to reduce the thickness of the second layer 5iOy film 21 at the inner and outer peripheral portions, it is possible to reduce cracks in these portions during firing.

In addition, 2 in the inner peripheral part and the outer peripheral part of the conductor coil I4
In order to reduce the v1 thickness of layer 5iOJ21, it is preferable to make the width of the dummy coil as large as possible if there is space available. For example, when the width dimension is increased as a whole like the dummy coil 14b on the left side of the outer periphery, if a gap 14r is provided in the center, the gold F
The bonding area between Ii (dummy coil 14b) and the insulator (insulating film 13) is made small, and the bonding area between the insulator (insulating film 17) and the insulator (
Since the bonding area between the insulating films 13) can be increased, this is advantageous in terms of rejuvenation strength. Also, front gap part 1
By reducing the line width of the dummy coils 14c and 14a in the vicinity of the 5 and back core connection portions 16 (see FIG. 3) to, for example, about 1 to 5 μm, the magnetic path length can be prevented from becoming too long and the present invention can be achieved. You will also be able to get better results.

(Effects of the Invention) As explained above, in the present invention, since the dummy coil is formed at the inner circumference and/or outer circumference of the conductive coil other than the top layer, it is possible to reduce the level difference in the part, Thereby, it becomes possible to reduce the thickness of the planarization coating film in the region.

In addition, when the conductor coil has three or more layers, a dummy coil is provided in each layer other than the top layer, and if it is extended to a position further away from the conductor coil in the radial direction as the bottom color approaches, it is possible to reduce the distance between adjacent layers. The above effect can be obtained.

Also, in the case of a multi-track element, the same effect can be obtained by installing a dummy coil at a location where a difference in thickness equal to or more than two conductor coil layers occurs.

[Brief explanation of drawings]

FIG. 1 shows a thin film magnetic head according to an embodiment of the present invention.
The plan view of the layered conductor coil, Figures 2 and 3 are the lines ■-■ and ■- in Figure 1, respectively.
FIG. 4 is a plan view of the first-layer conductor coil in a conventional thin film magnetic head; FIG. 5 is an enlarged partial cross-sectional view taken along line 1--2 in FIG. 4; 12.17...Conductor coil, 14 a-14e--dummy coil, 18.2I...Coating type 5iOz film for planarization. Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) In a thin film magnetic head in which multiple layers of conductive coils are stacked with a flattening coating film interposed between an upper magnetic core and a lower magnetic core made of soft magnetic thin film, the inside of the coils in each layer other than the top layer is A thin-film magnetic head characterized in that a dummy coil is formed on a peripheral portion and/or an outer peripheral portion to reduce the thickness of the coating film in that portion. (2) In a case where the conductor coil has three or more layers, the dummy coil is provided in each layer other than the top layer, and the dummy coil is extended to a position further away from the coil in the radial direction as the layer becomes lower. The thin film magnetic head according to the first item.