JPH0589625A - Method for polishing magnetic head slider - Google Patents

Abstract

PURPOSE:To highly accurately grind the running surface of a magnetic head slider to a flat surface. CONSTITUTION:A slider 2 is run on a grinding plate 1 while the slider 2 is fitted to a flexure arm 3. At the time of running the slider 2, the slider 2 can be made to float in a floating attitude which is decided by a point where the dynamical pressure of a fluid corresponding to the running speed and the pressing load from the arm 3 are balanced. An appropriate contact state can be selected between the slider 2 and polishing plate 1 by changing the running speed of the slider 2 by controlling the rotating speed of the polishing plate 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method for highly accurately flattening a running surface of a magnetic head slider used in a magnetic disk device.

[0002]

2. Description of the Related Art Ceramic materials, glass materials, composite materials of ceramics and glass, etc. are widely used in various fields by taking advantage of their excellent characteristics of having high hardness and wear resistance. A typical example thereof is a ferrite material used as a magnetic head slider material in a magnetic storage device for computers.

In recent years, devices of this type are required to have a higher recording density and a larger capacity, and in order to increase the recording density, a gap between the magnetic head slider and the recording medium (hereinafter,
The flying height) tends to be smaller than the current level of 2000 liters (0.2 μm). Magnetic head sliders (hereinafter referred to as sliders) have traditionally used mirror-finished lapping as a machining method in order to achieve machining accuracy such as high flatness and fine surface roughness associated with this low flying height. There is.

FIG. 6 is a side view showing a conventional method of mirror lapping. In FIG. 6, reference numeral 15 denotes a polishing plate, which is generally made of tin material, and has a large number of concentric circles or spiral fine grooves to be the polishing surface 17 formed on the surface. In the actual lapping, the polishing liquid 16 in which fine abrasive grains (for example, diamond paste 1 μm abrasive grains) are dispersed is applied to the polishing surface 17 to form a face plate.
Adhesive jig with adhesive 12 such as wax or resin on 14
The workpiece 11 fixed to 13 is opposed to the polishing surface 17, and both are rotated and slid to perform mirror lapping. In this case, a highly accurate polished surface with a flatness of about 500Å and a surface roughness of about 50Å has been realized.

[0005]

However, a slider that is compatible with lower flying heights for higher density recording in the future will achieve higher precision flatness for the purpose of achieving both head performance and reliability. It has been technically difficult to satisfy the requirement in the above-mentioned conventional mirror surface lapping.

The reason is that, in the conventional method of mirror lapping, the final shape of the workpiece is greatly affected by "initial shape before processing", "pasting load distribution", "contraction when the adhesive hardens", etc. This is because it is extremely difficult to improve the sex.

FIG. 7 is a view showing a conventional slider polishing process. First, as shown in (a), the face plate 14 is heated and the adhesive 12 such as wax is applied. Next, as shown in FIG. 6B, a sticking load F is applied from the outside to cool the work piece 11 as a slider so as to improve the sticking accuracy. At that stage, the deformation energy due to the attachment load F, and further the deformation energy caused by the difference in the thermal expansion coefficient between the workpiece 11 and the face plate 14 due to the temperature change during cooling have been generated. afterwards
In FIG. 6 (c), the mirror surface lapping shown in FIG. 6 is performed, and in FIG. 6 (d), the workpiece 11 is separated from the face plate 14.

As described above, in the conventional method, as shown in FIG. 3D, the deformation energy accumulated in the workpiece 11 at the time of bonding is released after the processing to cause re-deformation, which causes deterioration of flatness. That is, even if the processing accuracy in the bonded state is extremely high, it is technically difficult to prevent the release of the deformation energy generated inside the workpiece during the bonding, and therefore the processing accuracy is unavoidably deteriorated due to the re-deformation.

It is an object of the present invention to provide a method of polishing a magnetic head slider, which prevents deterioration of processing accuracy due to re-deformation after the conventional planar processing as described above.

[0010]

According to the present invention, a magnetic head slider is supported solely by a flexure arm, and the magnetic head slider is levitated on a rotating polishing plate by a dynamic pressure effect of a fluid so as to be finely spaced. The traveling surface of the magnetic head slider partially contacts the surface of the polishing plate, and the polishing progresses.

Further, the magnetic head slider is characterized in that it is made of at least one of ceramics and glass material.

Further, the polishing plate is characterized in that at least one of the wrapping tape and the abrasive grains is attached to the surface thereof.

[0013]

According to the method of polishing a magnetic head slider of the present invention, since the slider is kept very close to the normal use condition, the slider is not deformed at all, and the processing accuracy itself forms the running surface of the slider. Also, factors that deteriorate the flatness of the slider due to adhesive deformation and the like are eliminated, and the conventional method can be used as it is until the final assembly process step.

[0014]

FIG. 1 shows a polishing method according to an embodiment of the present invention. (A) is a perspective view showing polishing of a slider, (b)
[Fig. 3] is a side view of the side during polishing. As the slider 2 for the workpiece, one finished by a conventional lapping method is used, and the material is a ceramic material (for example, ferromagnetic ferrite, titanium burr, forsterite, glass, etc.). The slider 2 is point-bonded to the tip of the flexure arm 3, and the pressing load from the arm 2 and the dynamic pressure of the rotating polishing plate 1 such as air or alcohol-based lubricating liquid are balanced (b ) Levitate as shown in the figure. Note that (b)
In the figure, 4 is an air inflow end and 5 is an air outflow end.

The polishing plate 1 has fine abrasive grains adhered to the surface thereof, for example, a lapping tape is adhered thereto, fixed by plating, forcedly embedded in a metal surface, or further coated with an abrasive grain paste. It is fixed and the abrasive grains have a grain size of 1.
Alumina, diamond, silicon nitride, boron nitride, etc. of 0 μm or less are used.

When actually performing the polishing process, a landing-on system is used in which the polishing plate 1 is rotated and then the slider 2 is brought into close contact with the polishing plate 1.

The number of rotations of the polishing plate 1 at this time is determined by the slider 2
The critical floating state where only the protruding portion of the running surface continuously contacts the polishing plate 1 or the entire contact surface where the entire running surface contacts makes it possible to selectively select only the protruding portion that causes the flatness reduction. It is possible to perform various polishing.

Further, the slider 2 during polishing is fixed in the radial direction of the polishing plate 1 or is processed while swinging.
The polishing time varies depending on the grain size of the polishing plate 1, the material of the workpiece, etc., but is usually several seconds to several tens of seconds.

According to the present invention, the working accuracy after the actual working can be always 200 Å or less on all the sliding surfaces of the slider 2.

As described above, according to the present invention, the deformation energy due to the initial deformation of the workpiece due to the adhesion is not generated as compared with the conventional mirror surface lapping, so that the workpiece is not re-deformed after the processing, and the low deformation is achieved. It is possible to easily obtain, in a short time, highly accurate flatness required for traveling stability of the slider 2 that realizes flying. That is, the polishing (processing) accuracy itself can be the planarity of the slider 2.

FIG. 2 is a graph showing the relationship between the peripheral speed v of the surface of the polishing plate 1 and the flying height h of the slider 2.
Can be classified into the following four areas.

Completely floating region 6 ... In the region where the peripheral velocity v is (c) or higher, the slider 2 and the surface of the polishing plate 1 are completely in contact with each other without any contact, and no processing is performed. ..

・ Semi-floating region 7: peripheral speed v is (b) to (c)
In the region up to, the slider and the surface of the polishing plate are in a floating state where they suddenly contact each other.
Hardly progresses.

・ Critical levitation region 8 ... The peripheral velocity v is (a) or (b)
In the area up to, the slider and the surface of the polishing plate are always in contact with each other somewhere, and the protruding portion of the slider is selectively polished, resulting in higher precision than conventional mirror lapping. A flat slider can be easily realized in a short time.

Full surface contact area 9: In the area where the peripheral velocity v is (a) or less, the running surface of the slider and the surface of the polishing plate are in full contact, and naturally the entire surface is processed. It will proceed.

From the above four classifications, it is used that the peripheral velocity v of the critical floating region is (b) or less.

Normally, the peripheral speed is determined by the shape and size of the slider 2.
Since (b) is different, it is not possible to limit a certain peripheral speed. Therefore, polishing is actually performed at several peripheral speeds corresponding to each slider shape, the peripheral speed (b) is determined by the presence or absence of change in the planarity before and after processing, and then the peripheral speed (b) It suffices to determine an appropriate peripheral speed and running time (processing time).

FIG. 3 is a side view showing the flying state of the slider 2. FIGS. 3A and 3B show the flying state of the slider in the complete flying region 6 and the critical flying region 8, respectively, and the slider 2 is a flexure. The arm 3 is supported by a slider support spring 10. In (a), when the peripheral speed of the polishing plate 1 is high, the air inflow end 4 has a larger levitation amount than the air outflow end 5, and in (b) there is almost no difference in levitation amount. If so, the protruding portion of the slider 2 is selectively polished,
The flatness can be improved.

FIG. 4 is a diagram showing the running surface of the slider 2. FIGS. 4A, 4B, and 4C show the complete floating region 6, the critical floating region 8, and the entire surface contact region 9, respectively. It is shown in the figure when polishing. In Fig. (a), there is no machining surface because it is in a completely floating state. In Fig. (b), before polishing, there are two protruding parts on the running surface of the slider, and only that part is machined as shown by the horizontal line. ing. That is, only the portion that deteriorates the flatness is selectively processed, and as a result, the flatness is significantly improved.

Further, in the figure (c), since the slider 2 is traveling in a state where it hardly floats, the traveling surface is the processed surface as indicated by the horizontal line. This is because the running stability is lower than that of the one that floats even slightly, and in some cases, the posture of the slider 2 tilts back and forth, left and right during polishing, and "edge dripping" e occurs at each edge of the running surface as shown in FIG. May occur. However, except for the "edge sag" portion, the flatness is much improved as compared with the conventional slider.

It should be noted that the slider 2 having the above-mentioned "edge sag" has a higher effect of preventing a head crash and is more reliable than a slider 2 having a sharp edge. Therefore, if the degree of "edge sag" is controlled by the peripheral speed, the slider can be made highly reliable.

In FIG. 5, the shape of the running surface when a slider of Mg-Zn ferrite as a workpiece was actually polished by the method according to the present invention was measured by a non-contact optical three-dimensional surface roughness meter. This is an example. It can be seen that (a) is before processing and (b) is after processing, and the flatness after polishing is obviously improved.

The present invention has been described above. However, the present invention attaches the slider mirror-finished by the conventional lapping method to the flexure arm as described above and runs on the polishing plate without deforming the slider. The feature is that polishing can be performed while maintaining a stable posture.

[0034]

As described above, according to the method of polishing a magnetic head slider of the present invention, since the slider is kept extremely close to a normal use state, the slider is not deformed at all, and the processing accuracy itself is equal to that of the slider. A factor that forms a running surface and deteriorates the flatness of the slider due to adhesive deformation and the like is also eliminated, and processing for suppressing head crash of the magnetic disk can be performed. Furthermore, the conventional construction method can be used as it is until the final assembly process step.

[Brief description of drawings]

FIG. 1 is a perspective view and a side view showing a polished state in an embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the peripheral speed of the polishing plate and the flying state of the slider.

FIG. 3 is a side view showing a flying state of a slider.

FIG. 4 is a diagram showing a running surface of a slider before and after polishing according to the present invention.

FIG. 5 is a view showing the roughness of the surface of the slider measured before and after polishing according to an embodiment of the present invention.

FIG. 6 is a side view showing a polishing process of a conventional slider.

FIG. 7 is a diagram showing a conventional slider polishing process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Polishing plate, 2 ... Slider, 3 ... Flexure arm, 4 ... Air inflow end, 5 ... Air outflow end, 6 ... Completely floating area, 7 ... Semi-floating area, 8 ... Critical floating area, 9
… Full contact area, 10… Slider support spring, 11… Workpiece, 12… Adhesive, 13… Adhesive jig, 14… Face plate, 15
… Polishing plate, 16… Polishing liquid, 17… Polishing surface.

Claims (3)

[Claims] 1. A magnetic head slider is supported by a flexure arm as a single unit, and the magnetic head slider is levitated on a rotating polishing plate by a dynamic pressure effect of a fluid, so that a running surface of the magnetic head slider is increased. the above,
A method of polishing a magnetic head slider, characterized in that polishing progresses by partially contacting a surface of a polishing plate. 2. The method of polishing a magnetic head slider according to claim 1, wherein the magnetic head slider is formed of at least one of ceramics and glass material. 3. The method of polishing a magnetic head slider according to claim 1, wherein at least one surface of the polishing plate has a wrapping tape or abrasive grains attached thereto.