JPH07311912A - Manufacture of thin film coil - Google Patents

Abstract

PURPOSE:To smoothly fill an inorganic oxide without generating a void by covering a space left between wires of a coil with the inorganic oxide. CONSTITUTION:A seed layer 31 to be a base for plating a coil is formed of Ti or Cr on an insulating layer 6 by sputtering, and the layer 31 is coated with a photoresist 32. A photomask 33 is capped thereover, which is exposed to ultraviolet rays, developed and postbaked, whereby a resist pattern 35 with recessed parts 36 for plating is obtained. Thereafter, Cu is plated to the recessed parts 36 by electrolytic plating and wires 7a of a coil 7 are formed into a basic rectangular shape. Then, the photoresist 35 is separated and removed, and the seed layer 31 between the coil wires 7a is removed by ion beam etching or the like manner. A shoulder part 38 of each wire 7a of the coil 7 is processed slantwise if it is necessary. A height H, a width w and a depth D of the wise 7a are consequently set to be 3mum, 3mum and 3-4mum, respectively. An insulating material 8 of an inorganic oxide such as alumina, silicon oxide or the like is sputtered to cover an interval between the wires 7a and an upside of the wires 7a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to thin-film magnetic heads and thin-film motors used in high-density magnetic disk devices manufactured by thin-film technology, and more particularly to a method for manufacturing thin-film coils used in those products. Regarding

[0002]

2. Description of the Related Art Of the products manufactured by the above-mentioned thin film technology, for example, a thin film magnetic head is constructed as shown in FIGS. 4 (A) and 4 (B). In the figure, 1 is a slider substrate, 2 is a slider air bearing surface, 3 is a lower protective layer, 4 is a lower magnetic layer, 5 is a nonmagnetic layer, 6 is an insulating layer, 7 is a spiral coil, and 8 is a coil 7. Is an insulating material for maintaining electrical insulation between the wire rods 7a of the coil, 9 is a terminal of the coil 7, and 12 is an upper magnetic layer. 13 is a pole tip in the upper magnetic layer 12 and has a gap 14 with the lower magnetic layer 4.
Are formed. Reference numeral 15 is a yoke portion in the upper magnetic layer 12, and 16 is a coupling portion with the lower magnetic layer 4. The lower magnetic layer 4 and the upper magnetic layer 12 form a closed magnetic path with the gap 14 interposed therebetween.

The coil 7 is formed on the insulating layer 6 by a known dry etching method or an electrolytic plating means using a known resist pattern. In this case, the wire rod 7a of the coil 7 usually has a rectangular cross-sectional shape as shown in FIG. Then, a photoresist is spin-coated as the insulating material 8 to fill the space between the wire rods 7a and cover the upper side of the wire rod 7a with the photoresist 8 (see, for example, Japanese Patent Laid-Open No. 5-250632).
By doing so, it is possible to manufacture a thin-film coil having a high insulating property in which the wire 7a is covered with an insulating material.

[0004]

However, the above-mentioned thin-film coil has a problem that it tends to be deformed due to aging because the insulating material is photoresist. Further, whilst the coil 7 is formed by the dry etching method, a whisker-like metal protrusion may be formed on the edge 7b on the upper surface of the wire 7a. If such a protrusion is present, it may be filled with a photoresist and then used. Since the distance between the metals becomes shorter and the resist has a more brittle property than inorganic oxides, the above-mentioned protrusions deteriorate the insulation between the wire rods, and a state close to a short circuit easily occurs between the coils. There is a problem that it decreases.

In order to solve the problem of deformation due to aging, it is possible to make it extremely difficult to cause deformation by using, for example, an alumina or silicon-based inorganic oxide as the insulating material 8. However, as shown in FIG.
Voids 19 are easily formed in the inorganic oxide 18 between the wire rods 7a, and if such voids 19 are formed, there is a problem that the mechanical strength of the thin film coil of the finished product is weakened or the electrical characteristics are deteriorated. . Especially in recent years, since the number of turns of the conductor coil is increased to improve the reproduction sensitivity and the conductor cross section is increased to reduce the coil resistance value, the space between the coils is narrowed and the space height is relatively high. However, there is a problem in that the void generation condition is significantly increased.

In order to prevent the occurrence of the voids 19 as described above, as shown in FIG.
Is preferably formed so that its inlet portion 20a is wide.
For that purpose, a resist pattern for forming the wire rod 7a is formed into a shape as shown by reference numeral 21 in FIG. 7B (see, for example, JP-A-5-242430). However, when an attempt is made to form the wire 7a by electroplating with the resist pattern 21 having such a cross-sectional shape, the recess 22 into which the plating liquid should enter has a narrow inlet 23, so that the recess 24 in any of the multiple recesses 22. As a result, recesses 22 that are difficult to stir up to occur are generated, so that the ion concentration in such recesses 22 is likely to decrease, and as a result, the wire rods 7a formed in the recesses 22 have different thicknesses and the finished coil is defective. There is a problem that becomes.

The present invention has been made in order to solve the above-mentioned problems (technical problems) of the prior art.
It is an object of the present invention to provide a method for manufacturing a thin film coil in which an inorganic oxide is used as an insulating material, which is unlikely to be deformed due to aging.

A second object is that even if an inorganic oxide is used as an insulating material, the wires can be filled without forming voids between them, and the mechanical strength of the most important upper part of the wires is increased. Moreover, it is an object of the present invention to provide a method of manufacturing a thin-film coil having good electric characteristics.

[0009]

In order to achieve the above object, a method of manufacturing a thin-film coil according to the present invention is such that a coil formed on an insulating layer has a rectangular cross-section. On the other hand, a step of applying a resist in such an amount that the spaces between the wire rods in the coil are partially filled.
A step of flattening the resist overlying the upper surface of the coil to fill the space between the coils, and a step of covering the space left between the wire rods in the coil with an inorganic oxide are provided.

[0010]

[Function] When filling the inorganic oxides between the wire rods, the deep portions of the wire rods, which do not require relatively high strength, are filled with a resist having high fluidity to reduce the depth between the wire rods. By making the step small, the inorganic oxide can be smoothly introduced, and the inorganic oxide can be filled between the upper portions of the wire without generating voids. The inorganic oxide filled without voids between the upper positions of the wire exhibits effectively high mechanical strength and high electrical insulation.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. First, prior to the description, an example of a general method for forming a thin film coil will be described with reference to FIGS. First, as in (A), a seed layer 31 serving as a base for plating a coil is formed on the insulating layer 6 by sputtering. Titanium or chrome is used as the seed layer 31 because of its good adhesion to the insulating layer 6. Next, as shown in (B), a photoresist 32 is coated on the seed layer 31.
Next, as shown in (C), a photomask 33 is covered and exposed to ultraviolet rays 34. Then, it is developed and post-baked to form a resist pattern 35 having a recess 36 for plating as shown in FIG. Next, the recess is formed by electrolytic plating.
36 is plated with copper, and the wire 7a of the coil 7 is formed into a rectangular basic shape as shown in (E). Next, as shown in (F), the photoresist 35 is peeled and removed, and further, for example, by ion beam etching, a seed layer between the coil wire rods 7a as shown in (G).
Remove 31. In this way, the coil is formed.

The thin film coil shown in FIG. 1G can be formed by a well-known dry etching method different from the electrolytic plating means.

Next, if necessary, as shown in FIG. 1H, the shoulder portion 38 of each wire 7a of the coil 7 is obliquely cut off. The processing of the shoulder portion 38 can be performed by an ion beam processing device described later, but may be performed by a processing device using plasma arc discharge. The height H of the wire 7a is, for example, 3 μm, the width W is, for example, 3 μm, and the interval D is, for example, 3 to
4 μm, the width W1 of the slanted shoulder 38 is 3 to 1 of the width W
It is 0%, for example, about 5%, and the angle is about 45 degrees.
Next, as shown in (I), an inorganic insulating material 8 such as alumina or a silicon oxide-based inorganic oxide is sputtered to fill the spaces between the wire rods 7a and cover the upper side of the wire rods 7a. The covering thickness T is, for example, 3 μm.

Next, in this example, in order to form the coil in two layers, the steps (A) to (I) are repeated once more,
Another coil 40 is formed on the coil 7 as shown in FIG. 41 is a seed layer, 40a is a wire of the coil 40, 42
Is an insulating material (inorganic oxide). By completing the steps (A) to (J), the thin film coil including the two layers of coils 7 and 40 embedded in the insulating material is completed.
When the magnetic head has a structure having such two layers of coils 7 and 40, the electrical sensitivity can be improved. The coil may have one layer or more layers.

Next, the wire rod 7a by the ion beam processing device 45
2 which shows the removal processing of the corners of FIG. 46 is an ion beam generator, and 47 is a processing chamber, which is evacuated. Reference numeral 48 denotes a substrate holder, which is a first rotary disc 49 that rotates about a rotary shaft 49a and a second rotary disc that is mounted on the first rotary disc 49 and that rotates about a rotary shaft 50a that is parallel to the rotary shaft 49a. It has 50 and. The substrate holder 48
The angle θ between the arrival direction 51 of the ion beam from the ion beam generator 46 and the rotating shaft 50a can be arbitrarily set so that the irradiation direction of the ion beam with respect to the workpiece can be arbitrarily set. In the case of removing the shoulder of the copper wire rod 7a, the angle θ is set to, for example, 4
Set around 5 °.

The coil 7 has a direction 7d perpendicular to the surface direction 7c of the coil 7, as indicated by an arrow 51 in FIG.
The second turntable so that it is irradiated from the direction inclined with respect to
Attach to 50. The mounting may be performed as follows.
As is generally known in the thin film technology, the coils 7 are formed on one surface of a single substrate called a wafer by arranging a large number of the coils 7 in a state in which the surface direction 7c of each coil 7 is parallel to the one surface of the substrate. ing. Therefore, by mounting the substrate so that one surface thereof overlaps the disk surface of the second rotary disk 50, the direction 7d is substantially parallel to the rotary shaft 50a, and the direction 7d is at the set angle θ with respect to the direction 51. It can be tilted.

When ion beam irradiation is performed in this state,
As is clear from FIG. 3, the ion beam strikes the shoulder portion 38 of the wire 7a in a substantially straight direction and strikes the other portions in an inclined direction. Therefore shoulder
At 38, the ion beam etching progresses most, and eventually its corners are removed to form an oblique shape. The ion beam irradiation as described above is performed while rotating the first and second rotating disks 49 and 50. Then, the coil 7 is irradiated with the ion beam from any direction in which the angle θ set with the direction 7d is always maintained. As a result, the wire 7a of the spiral coil 7 has a slanted shoulder as described above at any part, and the inorganic oxide 8 can be easily filled and voids are less likely to be formed.

Next, the means for covering the large number of coil wire rods 7a, 7a and their upper surfaces with the inorganic oxide 8 as shown in FIG. 1G will be described with reference to FIG. Figure 1
Similarly to (G), a coil composed of a large number of coil wire rods 7a, 7a is formed on the insulating material 6 (see FIG. 5A). The method for forming this is as described above, and may be a dry etching method or an electrolytic plating method. Next, as shown in FIG. 5B, a resist having a property of fluidizing at a high temperature within a short time is applied on the coil wires 7a, 7a. A well-known spinner may be used as the means. The amount of the resist is set so that approximately half of the depth H between the coil wire rods 7a and 7a is filled with the resist 8a as shown in (C), and the remaining space 8b is formed above. In this case, as in (B), the resist 8c is also deposited on the coil wire rods 7a, 7a. Therefore, as the amount of the resist, since the resist 8c to be deposited is fluidized when brought into contact with a high temperature atmosphere (for example, 200 ° C.) as is well known, and flows into between the coil wire rods 7a and 7a. It is good to set the expected amount. When the amount of the resist 8c is large, it may be removed. In this way, the resist in the state of (B) is fluidized to the state of (C).
When the cross section as shown in (C), that is, between the coil wire rods 7a and 7a is already filled with the resist 8a and is shallow, it is possible to cover these coils with an inorganic oxide by sputtering. Inorganic oxides easily enter between the coil wire rods 7a, 7a, and voids as shown in FIG. 6 cannot occur. Therefore, when the inorganic oxide is sputtered on the coil, the relatively shallow groove 8b between the coil wire rods 7a and 7a is completely filled with the inorganic oxide 8b as shown in (D).
The entire coil is also covered as shown in FIG.

As shown in (I) of FIG. 1, the inorganic oxides are stacked between the upper positions of the coil wire rods 7a, 7a of (D) as shown in (I) of FIG. )
As shown in FIG. However, depending on the application, as shown in FIG. 5E, the inorganic oxide 8e above the upper surface of the coil wire rods 7a and 7a in (D) is removed by a known polishing means, and the upper surface 8f of the coil wire rods 7a and 7a is removed. The inorganic oxide 8d and the inorganic oxide 8d may have the same height.

[0020]

As described above, according to the invention of the present application, the above-described object is achieved, and even if the distance between the coil wire rods 7a and 7a is relatively narrow, the depth between the coil wire rods 7a and 7a is small. Even though it is relatively deep, the lower deep part between the coil wire rods 7a and 7a is filled with a highly fluid resist and changes shallowly. Has the effect of smoothly filling the inorganic oxide, and in particular, filling the inorganic oxide while preventing the generation of voids.

[Brief description of drawings]

1A to 1J are cross-sectional views showing a procedure for forming a thin film coil.

FIG. 2 is a partially cutaway view schematically showing an ion beam processing apparatus.

FIG. 3 is an enlarged view showing an etching state by an ion beam.

FIG. 4A is a vertical sectional view of a thin film magnetic head, and FIG. 4B is a plan view.

5 (A) to (E) are coil cross-sectional views showing a procedure for applying an inorganic oxide to a thin film coil.

FIG. 6A is an enlarged vertical sectional view of a conventional thin film coil,
FIG. 6B is a vertical cross-sectional view of the thin film coil showing a state in which voids are formed.

FIG. 7A is a diagram showing another example of the cross-sectional shape of the wire rod in the conventional coil, and FIG. 7B is a diagram showing the cross-sectional shape of the resist pattern for forming the wire rod of FIG.

[Explanation of symbols]

 7 Coil 7a Wire rod 8 and 8d Insulation material 19 Void

Claims (1)

[Claims] 1. A step of applying an amount of resist on the upper surface of a coil formed on the insulating layer and having a rectangular cross section, so that the space between the wires in the coil is partially filled. A method for manufacturing a thin-film coil, comprising: a step of flattening a resist overlying an upper surface of the coil to fill spaces between the coils; and a step of covering a space left between wires in the coil with an inorganic oxide. .