JPH0729120A - Manufacture of thin film magnetic head - Google Patents

Abstract

PURPOSE:To easily control the amount of a recess by providing a step for polishing a floating surface of a slider member and a step for dipping the slider member into an aqueous solution of polyethylene glycol after the polishing step. CONSTITUTION:Many magnetic head elements are arranged on a wafer 10 of ceramic. The whole of the wafer 10 is cut square. Then, a processing jig 13 is bonded at the side opposite to an ABS surface (floating surface) 12 of a cut bar 11. Grooves are formed from the side of the ABS surface 12, and a rail 15 of a slider 14, etc., are formed. A breed slot is formed from the side of the ABS surface 12. The ABS surface 12 is then finished by polishing. Subsequently, the slider is dipped in an aqueous solution of polyethylene glycol, thereby to control the amount of a recess. Thereafter, each slider 14 is separated from the processing jig 13 and cleaned, resulting in the final product.

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 a magnetic disk device, and more particularly to a thin film magnetic head devised for processing an air bearing surface (hereinafter referred to as ABS surface) of a slider member. It relates to a manufacturing method.

[0002]

2. Description of the Related Art In manufacturing a thin film magnetic head of this type, generally, a step of forming a plurality of magnetic head elements on a wafer serving as a substrate by a thin film integration technique, and the thin film magnetic head element thus formed. At least a step of cutting the wafer into a plurality of bars, a grooving step of forming a necessary groove on each of the cut bars from the ABS surface side, and a polishing step of polishing the ABS surface of each bar with high accuracy are performed. It

This polishing process is mainly for adjusting the gap depth (throat height) of each magnetic head element to a constant level, but since the ABS surface where layers of different materials are exposed is polished at the same time. A processing step called a recess is formed between different material layers.

FIG. 5 is a partial cross-sectional view showing the periphery of the magnetic head element after a conventional polishing process has been performed to explain this recess. In the figure, 50 is Al ₂ O ₃ −.
A slider formed of a very hard ceramic material such as TiC, 51 is an insulating layer made of Al ₂ O ₃ or the like formed on the rear end surface of the slider 50, and 52 and 53 are Ni-layers laminated on the insulating layer 51. The magnetic pole layer 54 is made of a soft metal material such as Fe (permalloy), and 54 is the magnetic pole layer 5.
2 is an interlayer insulating layer made of Al ₂ O ₃ or the like provided between 53, 55 is a coil conductor, 56 is a protective film made of Al ₂ O ₃ or the like laminated on the magnetic pole layers 52 and 53, and 57 is AB.
The S-planes are shown.

Since the insulating layer 51 made of Al ₂ O ₃ or the like, the interlayer insulating layer 54 and the protective film 56 are softer in material than the slider 50 made of Al ₂ O ₃ —TiC or the like, they can be polished by the conventional technique. When done, the recess 58 causes the slider 5 to
It occurs between 0 and the insulating layer 51. The recess amount (depth) in this case is represented by d ₁ in the figure. In addition, Ni-F
Since the magnetic pole layers 52 and 53 made of e or the like are made of a softer material than the insulating layer 51 made of Al ₂ O ₃ , the interlayer insulating layer 54 and the protective film 56, the recess 59 in the direction of receding from the ABS surface 57 is formed. Occurs in this part. The recess amount in this case is represented by d ₂ .

The recesses 58 and 5 are formed on the basis of the difference in polishing efficiency due to the difference in hardness of each material on the polishing surface.
When No. 9 occurs, the distance between the magnetic medium and the magnetic pole becomes large, so that it is difficult to achieve high recording density even if the flying height of the slider is reduced. Therefore, it has already been proposed to reduce the recess amount by forming the slider and the protective film with the same material (Japanese Patent Laid-Open No. 62-214507). If the same material is used, the occurrence of recesses can be surely prevented, but this method cannot be adopted for the recesses 59 because the pole layer and the protective film cannot be made of the same material.

[0007]

In order to reduce the recess amount including the recess 59 of the magnetic pole layer, the applicant of the present invention intends to make the slurry (for example, diamond powder) of the polishing liquid into fine particles, and the processing surface plate. We tried to optimize the hardness by changing the material. However, it has been extremely difficult to control all recess amounts to desired values by such polishing.

For example, when the recess amount is to be suppressed to 100 Å or less, the recesses of the insulating layer 51, the interlayer insulating layer 54 and the protective film 56 with respect to the slider 50 and the slider 50.
Although the recesses of the pole layers 52 and 53 with respect to the magnetic pole layers 52 and 53 could be controlled to some extent, the recesses of the pole layers 52 and 53 with respect to the insulating layer 51, the interlayer insulating layer 54, and the protective film 56 could not be appropriately controlled. That is, it is difficult to control because the phenomenon that the magnetic pole layer becomes flat with respect to the protective film or the magnetic pole layer projects from the ABS surface of the protective film by about 10 to 20 Å. When the pole layer is flat on the protective film, there is no problem at all, but when the protrusion is formed, it becomes a serious problem from the viewpoint of reliability of the magnetic head. Ion milling may be performed after the polishing step in order to remove such protrusions (protrusions) of the pole layer, but this leads to a significant increase in the number of steps and an increase in cost. There's a problem.

Accordingly, the present invention provides a method of manufacturing a thin film magnetic head capable of suppressing the amount of recess within a desired range while minimizing the increase in cost.

[0010]

According to the present invention, a method of manufacturing a thin film magnetic head comprises a step of polishing an air bearing surface of a slider member on which a thin film magnetic head element is formed,
After this step, a step of immersing the slider member in a polyethylene glycol aqueous solution is provided.

[0011]

First, a magnetic head element is formed on a wafer made of a ceramic material by a thin film integration technique. in this case,
The magnetic head elements are formed so as to be arranged in a plurality of rows on the wafer surface. Next, the wafer is cut to cut each row of the magnetic head elements thus formed in a plurality of rows into a bar state. After forming necessary grooves from the ABS surface side of each cut bar, the ABS surface of each bar is finish-polished. After finishing polishing, each bar is dipped in a polyethylene glycol aqueous solution. The polyethylene glycol aqueous solution has a selective etching effect only on the magnetic pole layer, and has no etching effect on other layers such as the protective film, the insulating layer, and the interlayer insulating layer. Since the etching amount is controlled by the immersion time in the polyethylene glycol aqueous solution, even if the above-mentioned protrusions (projections) are formed on the pole layer by polishing, the protrusions can be formed by immersing the protrusions in the polyethylene glycol aqueous solution. The recess amount can be controlled to zero or negative, that is, a concave shape, very easily.

[0012]

1 (A) to 1 (J) are process drawings showing an embodiment of a method of manufacturing a thin film magnetic head according to the present invention.

First, a large number of magnetic head elements are formed in a plurality of rows on a wafer 10 made of a ceramic material such as Al ₂ O ₃ —TiC by a thin film integration technique. Then
After forming shallow grooves (not shown) for cutting into a plurality of bars on this wafer 10, the entire wafer 10 is cut into a rectangular shape as shown in FIG. Next, as shown in FIG. 1B, the wafer 10 is cut and each row of magnetic head elements formed in a plurality of rows is cut out into a bar 11. The cutting of the wafer 10 is performed by a disc-shaped diamond grindstone.

Next, as shown in FIG. 1C, a processing jig 13 made of metal or ceramics and having a rectangular parallelepiped shape is adhered to the surface of the cut bar 11 opposite to the ABS surface 12. Next, as shown in FIG. 1D, the surface of the ABS 12 is ground, and the surface height is roughly adjusted.

Next, as shown in FIG. 1E, groove processing is performed from the ABS 12 side, and the rail 1 of each slider 14 is processed.
5 etc. are formed. Although only a part of the slider portion of the bar 11 is shown in FIGS. 1E to 1J, a large number of sliders are actually provided as shown in FIG. 1D. . Then, as shown in FIG.
Grooves are further processed from the BS surface 12 side to form bleed slots 16.

Next, as shown in FIG. 1G, the ABS surface 12 of the rail 15 is finish-polished. In this finish polishing, a metal surface plate is used, and fine diamond powder is used as a slurry of the polishing liquid so as to suppress the recess amount to 100 Å or less. In this process,
It is required that the flatness of the ABS surface 12 of the slider 14, the throat height, and the recess amount satisfy predetermined criteria. However, if the recess amount is set to 100 Å or less, as described above, A
The pole layer made of Ni-Fe (permalloy) or the like becomes flat with respect to the protective film made of l ₂ O ₃ or the like, or 10 to 20
Å About the phenomenon of protruding from the ABS surface occurs. Therefore, in the present embodiment, after the finish polishing step, as shown in FIG.
As shown in FIG. 6, the slider (bar 11 attached to the jig 13) is dipped in the polyethylene glycol aqueous solution 17, and the dipping time is adjusted appropriately to selectively project the protrusions (projections) formed on the pole layer. The amount of protrusion recess is controlled to zero or negative by etching.

2A to 2C are partial cross-sectional views showing the magnetic head element and its periphery before the final polishing step, after the final polishing step and after the dipping step performed thereafter. In these figures, 20 is Al ₂ O
A slider 21 made of a ceramic material such as _3- TiC is a slider 21 formed on the rear end surface of the slider 20.
an insulating layer made of l ₂ O ₃ or the like; 22 and 23 are magnetic pole layers laminated on the insulating layer 21 and made of a metal material such as Ni--Fe;
24 is an interlayer insulating layer made of Al ₂ O ₃ or the like provided between the magnetic pole layers 22 and 23, 25 is a coil conductor, and 26 is a magnetic pole layer 2.
2 and 23 and the like are protective films made of Al ₂ O _{3 and the} like, and 27 is an ABS surface, respectively.

When the final polishing process is performed on the magnetic head shown in FIG. 2A, the slider 20, the insulating layer 21,
Regarding the interlayer insulating layer 24 and the protective film 26, the ABS surface 2
7 becomes almost flat with steps less than 100Å. However, in some cases, protrusions 22a and 23a having a height of about 10 to 20Å as shown in FIG. 2B may be formed on the pole layers 22 and 23. Therefore, in such a case, by immersing this slider in the polyethylene glycol aqueous solution 17 in the step of FIG.
Only the convex portions 22a and 23a of 2 and 23 are selectively etched and removed, and as shown in FIG.
The recess amount is controlled so that the ABS surfaces of Nos. 23 and 23 are flush with the other layers or are slightly recessed.

The recess amount is controlled by controlling the immersion time in the polyethylene glycol aqueous solution 17. Polyethylene glycol has a function of etching only a metal material such as Ni-Fe. Therefore, by utilizing this action, the recess amount of the magnetic pole layers 22 and 23 is controlled by controlling the time for immersing the magnetic head in the polyethylene glycol aqueous solution. The relationship between the immersion time in the polyethylene glycol aqueous solution and the etching amount of Ni-Fe is shown in FIGS. 3 and 4.

FIG. 3 shows the case where the Ni-Fe material is immersed in a polyethylene glycol aqueous solution prepared by dissolving two kinds of polyethylene glycols (# 200 and # 400) having different average molecular weights in pure water at a ratio of 1: 9. The etching amount (depth) with respect to the immersion time is measured. As is clear from the figure, the aqueous solution of polyethylene glycol # 200 has a higher dependence of the etching amount on the immersion time.

FIG. 4 shows a # 200 polyethylene glycol aqueous solution (polyethylene glycol:
This is a measurement of the etching amount with respect to the immersion time when the Ni—Fe material was immersed in pure water 1: 9 and 2: 8). As is clear from the figure, there is a difference in the etching rate depending on the concentration, and in the case of # 200 polyethylene glycol, the etching rate increases when the concentration in pure water is increased. Since the control of the recess amount is easier when the etching rate is moderately slow, the ratio of polyethylene glycol: pure water is preferably 1: 9.

From the experimental results shown in FIGS. 3 and 4, it can be seen that an aqueous solution prepared by dissolving # 200 polyethylene glycol in pure water at a ratio of 1: 9 is optimal for controlling the recess amount.

After finishing polishing and controlling the recess amount in this manner, the chamfer 18 of the rail 15 is formed by polishing, as shown in FIG. 1 (I). Then, FIG.
As shown in (J), the bar 11 is cut and separated into individual sliders 14. Thereafter, each slider 14 is removed from the processing jig 13 and washed to obtain a final slider.

As described above, in this embodiment, the slider is subjected to the final polishing step and then to the slider dipping step in the polyethylene glycol aqueous solution, and the protrusion of the pole layer with respect to the protective film is controlled so as to be almost flat. It In particular, since the etching amount is controlled by controlling the immersion time in the aqueous solution, the operation is extremely easy, and a high-performance magnetic head can be manufactured without significantly increasing the number of manufacturing steps and minimizing the increase in manufacturing cost. It is possible to provide it while suppressing it.

In the above embodiment, the step of immersing the slider in the aqueous solution of polyethylene glycol is performed after the step of finish polishing the slider. However, this step of immersing may be performed at any stage after the finish polishing step. Good.

[0026]

As described in detail above, according to the present invention, the step of polishing the air bearing surface of the slider member on which the thin film magnetic head element is formed, and the slider member after this step are treated with a polyethylene glycol aqueous solution. Therefore, the recess amount can be suppressed to a desired range without increasing the number of manufacturing steps and minimizing the increase in cost.

[Brief description of drawings]

FIG. 1 is a perspective view showing a part of steps in an embodiment of a manufacturing method according to the present invention.

FIG. 2 is a partial cross-sectional view showing the periphery of a magnetic head element in the case where each step in the embodiment of FIG. 1 is performed.

FIG. 3 is a characteristic diagram showing a relationship between an immersion time in a polyethylene glycol aqueous solution and an etching amount of a Ni—Fe material.

FIG. 4 is a characteristic diagram showing the relationship between the immersion time in a polyethylene glycol aqueous solution and the etching amount of a Ni—Fe material.

FIG. 5 is a partial cross-sectional view showing the periphery of the magnetic head element after a conventional polishing process is performed.

[Explanation of symbols]

 10 Wafer 11 Bar 12, 27 ABS Surface 13 Processing Jig 14, 20 Slider 15 Rail 16 Bleed Slot 17 Polyethylene Glycol Aqueous Solution 18 Chamfer 21 Insulating Layer 22, 23 Pole Layer 24 Interlayer Insulating Layer 25 Coil Conductor 26 Protective Film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Kohata 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Corporation (72) Inventor Hidetoshi Satsuka 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Incorporated (72) Inventor Kazuhiro Yanagisawa 1-13-1, Nihonbashi, Chuo-ku, Tokyo TDK Corporation

Claims (1)

[Claims] 1. A method comprising: a step of polishing an air bearing surface of a slider member having a thin film magnetic head element formed thereon; and a step of immersing the slider member in a polyethylene glycol aqueous solution after the step. Method for manufacturing thin film magnetic head.