JPH0721524A - Production of thin-film magnetic head - Google Patents

Abstract

PURPOSE:To secure the insulation between magnetic-pole coils and to pattern a conductor coil with high precision by forming an insulating film having a necessary thickness on a magnetic film formed on a substrate, flattening the insulating film and then forming a conductor coil film on the insulating film. CONSTITUTION:A lower magnetic film 3 is formed on the insulating film 2 of a substrate 1, and an insulating film 5 having a thickness larger than the height of the film 3 is formed with a gap film 4 in between. The film 5 is machined, e.g. lapped, or etched and flattened, and a conductor coil film forming a magnetic circuit with the film 3 is formed on the flat surface. As a result, the insulation between the magnetic-pole coils is secured, the dielectric breakdown voltage is increased, the conductor coil is patterned with high precision, and a highly reliable thin-film magnetic head is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a thin film magnetic head used in, for example, a magnetic disk device or other magnetic recording / reproducing device.

[0002]

2. Description of the Related Art Conventionally, a thin film magnetic head has been adopted in order to improve the recording density and the information transfer rate as the performance of a magnetic disk device is improved. Generally, a thin film magnetic head is manufactured by using a deposition technique such as electroplating or sputtering, and a fine processing technique by photolithography.

5 and 6 schematically show the structure of a conventionally known in-plane recording / reproducing thin-film magnetic head. An insulating film 2 made of alumina or the like is deposited on a substrate 1 made of an Al ₂ O ₃ —TiC-based ceramic material or the like, and a lower magnetic film 3 forming a lower magnetic pole is formed thereon. A gap film 4 made of alumina or the like is formed on the lower magnetic film 3.
Is formed, and insulating films 5, 6, 7 made of an organic insulating resin material such as a novolac resin, spiral coil coils 8, 9 made of Cu, and an upper magnetic film 10 are sequentially laminated thereon. Further, a protective film 11 made of alumina or the like is formed on the upper magnetic film 10 by sputtering or the like. The thin film magnetic head element thus formed is cut out from the substrate and mounted on each slider to be used as a thin film magnetic head.

[0004]

According to the prior art, the insulating film is usually coated with, for example, a novolac resin, soft-baked, exposed with a photomask, developed, heat-treated and cured. It is formed. Since the novolac resin has fluidity due to heat and shrinks by baking, the first insulating film 5 has a step difference between the lower magnetic film 3 and the substrate 1 as shown in FIG. The thickness near the edge of 3 becomes very thin. Figure 8
The relationship between the withstand voltage of the insulating film and the distance D between the upper end of the lower magnetic film 3 where the insulating film 5 is thinnest and the conductor coil 8 and the withstand voltage of the insulating film is shown in a diagram based on experimental results. From the figure,
In this experiment, it is easily understood that the withstand voltage drastically decreased when the distance D was 1 μm or less. As described above, when the first conductor coil 8 formed on the first insulating film 5 and the lower magnetic film 3 are too close to each other at their edge portions, sufficient insulation is not maintained and the magnetic pole coils are not separated from each other. There is a problem that the insulation resistance and the dielectric breakdown voltage are lowered, and the recording / reproducing of information by the thin film head may not be normally performed.

Further, if the entire first insulating film 5 is formed thicker, the thickness of the first insulating film 5 near the peripheral edge of the lower magnetic film 3 can be sufficiently secured, but the leading end portion of the upper magnetic film 10 rises. Since the angle becomes extremely steep, the internal stress of the protective layer 11 formed thereon becomes large and cracks or the like may occur, which may reduce the reliability.

Therefore, the method of manufacturing the thin-film magnetic head according to the first aspect is made in view of the above-mentioned problems of the prior art, and the purpose thereof is to make the substrate by a relatively simple process. Even at the edge of the magnetic film formed above, the film thickness of the insulating film formed on the magnetic film and the conductor coil can be sufficiently secured without causing cracks or the like in the protective layer. An object of the present invention is to provide a method of manufacturing a thin film magnetic head, which can ensure good insulation with a film, increase the breakdown voltage, and improve reliability.

[0007]

SUMMARY OF THE INVENTION The present invention is to achieve the above object, and a method of manufacturing a thin film magnetic head according to claim 1 comprises a magnetic film and a conductor coil film on a substrate. In a thin film magnetic head having a magnetic circuit
An insulating film is provided on the substrate including the magnetic film so as to be thicker than the upper surface of the magnetic film as a whole by a certain height or more, and at least a part of the insulating film higher than the magnetic film is removed to planarize After that, a conductor coil film is formed thereon.

[0008]

Therefore, according to the method of manufacturing the thin film magnetic head of the first aspect, the excess portion is appropriately removed from the upper surface of the thickly formed insulating film, regardless of the step between the magnetic film and the substrate. The film thickness of the insulating film between the magnetic film and the conductor coil can be easily controlled, and the film can be evenly provided including the edge portion of the magnetic film, thus ensuring good insulation between the magnetic pole coils. be able to.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings and preferred embodiments.

FIG. 1 shows a first embodiment of the present invention.
The process of providing an insulating layer on the lower magnetic film of the in-plane recording / reproducing thin film magnetic head is shown. As shown in Figure 1-A,
Substrate 1 made of Al ₂ O ₃ -TiC conductive ceramics
Is coated with an alumina insulating film 2 by a usual method, and a lower magnetic film 3 made of a soft magnetic material such as Ni—Fe alloy or cobalt alloy is formed thereon by patterning by electroplating, sputtering or the like. ing. A gap film 4 made of a non-magnetic insulating material such as alumina is formed on the lower magnetic film 3 by sputtering. Next, the organic insulating film including the lower magnetic film 3 is laminated on the substrate 1.

First, as shown in FIG. 1-B, a photoresist 5 made of an organic insulating resin material such as novolac resin is applied thicker than usual. This thickness is set so that the film thickness after sintering by the subsequent heat treatment is sufficiently higher than the upper surface of the lower magnetic film 3 even in the portion other than the portion above the lower magnetic film 3. When the film thickness is usually 2 to 5 μm, it is about 5 to 8 μm. The photoresist 5 is
As shown in FIG. 1-C, a photomask 12 is applied and exposed, then developed and washed with water, and unnecessary portions are removed as shown in FIG. 1-D. When this is heat-treated or UV-baked and sintered, the insulating film 5 is formed as shown in FIG. 1-E. The insulating film 5 has a portion of the lower magnetic film 3 which is raised due to a step between the substrate 1 and the lower magnetic film 3, but the insulating film 5 as a whole is sufficiently higher than the upper surface of the lower magnetic film 3 including the other portions. There is. The height may be such that the insulating property with the conductor coil laminated on the insulating film 5 is sufficiently secured even in the vicinity of the edge portion of the lower magnetic film 3.
The novolac resin usually has a film thickness of 5 to 1 due to sintering.
Since it decreases by about 5%, if the desired film thickness cannot be obtained in one step, the steps shown in FIGS.

Next, mechanical processing such as lapping is applied to the upper surface of the insulating film 5 to remove unnecessary portions, and the insulating film 5 is flattened to a necessary and sufficient height. For example, as shown in FIG. 2, the substrate 1 is placed on the flat polishing plate 13 with the insulating film 5 facing downward. As the polishing plate 13, for example, a conventional one made of metallic tin can be used, and diamond powder having a particle size of about 0.5 μm may be used as free abrasive grains. Lapping is performed by rotating the substrate 1 arranged as shown in FIG. 2 while applying a load from above. As described above, in the insulating film 5, the region of the lower magnetic film 3 is raised.
By lapping at a rotation speed of about m for 1 to 2 minutes, the raised portions can be removed from the insulating film 5 and the entire upper surface can be polished to be flattened as shown in FIG. 1-F. At this time, if the thickness of the insulating film 5 is about 0.5 to 2 μm on the lower magnetic film 3, a necessary and sufficient insulating property can be obtained, which is convenient. Further, in such a lapping process, the film thickness of the insulating film can be controlled with high accuracy of about +/− 0.5 μm when a 10 cm (4 inch) square wafer is used as a substrate, which is sufficient. Yield is obtained. In another embodiment, lapping can be performed with a polishing sheet using a diamond powder having a particle size of about 0.5 μm. In this case, the polishing sheet is fixed on a table such as a granite surface plate, and the substrate 1 is moved by about 20 mm while pressing the insulating film 5 against the polishing sheet, so that a flat and desired film thickness is obtained. The insulating film of is obtained.

Thereafter, a resist pattern is formed on the insulating film 5 by the same process as the conventional process, and the spiral first conductor coil 8 made of Cu is formed by electroplating. Further, the second insulating film 6, the second conductor coil 9, the third insulating film 7, the upper magnetic film 10 and the protective layer 11 are sequentially laminated to manufacture a thin film magnetic head. At this time, since the first conductor coil 8 is formed on the flat insulating film 5, the exposure focus can be one point when the resist pattern is formed,
Since the coil width and film thickness are formed more accurately, it is possible to prevent short-circuiting and disconnection of the coil.

3 and 4 show the steps of forming an insulating film made of an inorganic oxide such as alumina in the second embodiment of the present invention. Similar to the case of the first embodiment, the insulating film 2, the lower magnetic film 3 and the gap film 4 are laminated on the substrate 1 (FIGS. 3-A and 4-A). First,
As shown in FIGS. 3B and 4B, a negative resist 14 of polyimide resin is formed on the region of the substrate 1 including the lower magnetic film 3.
Is thickly applied, for example, about 15 to 25 μm. Next, the negative resist 14 is soft-baked, exposed to a photomask 15 as shown in FIGS. 3C and 4-C, exposed, developed, and then annealed at a temperature of 200 to 500 ° C. At this time, the negative resist 14 remaining around the lower magnetic film 3 is exposed so that the edge portion of the negative resist 14 has an inverse taper shape as shown in FIGS. 3D and 4D.

Next, a film thickness of 5 to 8 is formed by sputtering.
A film of alumina having a thickness of μm is formed (FIG. 3-E, FIG.
E). When the remaining negative resist 14 is removed by using hydrazine or the like, as shown in FIGS. 3F and 4F, the region of the lower magnetic layer 3 is raised and the lower magnetic layer is also formed in other regions. An insulating film 5 thicker than the film 3 is obtained. This film thickness is determined in consideration of the insulating property between the conductor coil laminated thereon and the lower magnetic film 3, as in the case of the first embodiment described above. The insulating film 5 is formed as in the first embodiment.
By polishing by lapping
G and the flat insulating film 5 of FIG.
Can be obtained. In addition, the first and second conductor coils 8 and 9, the interlayer insulating films 6 and 7, and the upper magnetic film 1 are formed on the insulating film 5.
When 0 or the like is laminated, the interlayer insulating films 6 and 7 can be similarly formed of an inorganic oxide of alumina.

In another embodiment, which is a modification of the above first and second embodiments, a chemical method such as an etch back method in which a lithographic technique and dry etching such as ion milling are used in combination is used instead of mechanical processing by lapping. The insulating film 5 can be planarized by the method. in this case,
On the insulating film 5 of FIGS. 3-F and 4-F, the above-mentioned photoresist of polyimide resin is applied and baked so that the step is completely filled. Then, the photoresist and excess alumina are etched by ion milling. At this time, it is necessary to remove the photoresist and the alumina portion of the insulating film at the same rate.
For example, in the case of ion milling using argon ions,
The incident angle on the substrate may be set to 30 °.

The present invention is not limited to the above-described embodiments, but can be carried out by making various modifications and changes within the technical scope thereof. For example, the present invention can be similarly applied to a perpendicular recording / reproducing thin film magnetic head. Further, in the above embodiment, the gap layer 4 was formed before forming the insulating film 5, but it goes without saying that a similar thin film magnetic head can be obtained by forming it after forming the insulating film 5.

[0018]

Since the present invention is constituted as described above, it has the following effects.

According to the method of manufacturing the thin-film magnetic head of the first aspect, the flat insulating film can be easily and easily formed on the magnetic film despite the considerable step between the magnetic film and the substrate. Since the film can be formed while controlling the film thickness, sufficient insulation is ensured between the magnetic pole coils including the edge portion of the magnetic film, and the dielectric breakdown voltage can be increased. Since it is formed on a flat insulating film, highly precise patterning is possible and reliability is greatly improved.

[Brief description of drawings]

1A to 1F are cross-sectional views showing respective steps of a method of manufacturing a thin film magnetic head according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a procedure for lapping an insulating film.

3A to 3G are cross-sectional views similar to FIG. 1 showing the respective steps of the manufacturing method according to the second embodiment of the present invention.

4A to 4G are vertical sectional views corresponding to the respective steps of FIG.

FIG. 5 is a schematic perspective view showing the structure of a conventional thin film magnetic head.

6 is a vertical cross-sectional view of the thin film magnetic head shown in FIG.

7 is a sectional view taken along line VII-VII in FIG.

FIG. 8 is a diagram showing a relationship between a distance D between an upper end of a lower magnetic film and a conductor coil and a withstand voltage of an insulating film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Insulating film 3 Lower magnetic film 4 Gap film 5, 6, 7 Insulating film 8, 9 Conductor coil 10 Upper magnetic film 11 Protective layer 12 Photomask 13 Polishing plate 14 Photoresist 15 Photomask

Claims (1)

[Claims] 1. A method of manufacturing a thin film magnetic head having a magnetic circuit comprising a magnetic film formed on a substrate and a conductor coil film formed on the substrate with an insulating film interposed therebetween, wherein the magnetic film A step of forming the insulating film as a whole on the substrate including a thickness greater than a certain height from the upper surface of the magnetic film, and removing at least a part of the insulating film higher than the magnetic film. And planarizing the conductor coil film, and then forming the conductor coil film.