JPS6161193B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a floating magnetic head with a minute levitation amount used in magnetic disk devices, etc., which has a structure added thereto for extracting dynamic fluctuations in the minute levitation amount as an electrical signal. The present invention relates to a magnetic head, and more specifically, it relates to an improvement in a levitating magnetic head having a structure that allows the amount of levitation to be measured by the capacitance method.

In magnetic disk drives, in order to keep the tiny gap between the recording medium and the magnetic head stable, the dynamic pressure of the gas film boundary layer that is generated on the surface of the magnetic disk as the recording medium rotates is used. A floating magnetic head is used, which is opposed to the surface of the magnetic disk with a small amount of levitation.

In a levitating magnetic head, the amount of levitation has a dominant influence on its electromagnetic properties, and in order to improve the performance of magnetic disk drives, it is necessary to miniaturize the amount of levitation and reduce dynamic fluctuations in the amount of levitation. Stabilization of the floating posture is required. To meet these demands, a measurement method that directly extracts dynamic minute fluctuations in the amount of levitation as an electrical signal is required, and this involves measuring the capacitance between the electrode surface formed on the magnetic head and the magnetic disk surface. The capacitance method, which calculates the amount of levitation using

Next, a conventional magnetic head for measuring the amount of levitation will be explained with reference to the drawings.

FIG. 1 is a perspective view of a conventional magnetic head for measuring the amount of levitation, in which 101 is a slider made of a non-conductive material, 102a, b, c are slider levitation surfaces, and 103 are slider levitation surfaces 102a, 102b.
The surface of this metal film 103, which is formed on the same plane as the slider floating surface, is embedded in the slider 101 and connected to the slider 101 via a vapor deposited film (not shown). 4 electrode surfaces 104
is formed. Reference numeral 105 denotes a vapor deposited metal film which is electrically connected to the metal film 103 by plating, and is electrically connected to a lead wire (not shown) on the back surface of the slider.

In order to manufacture this magnetic head, it is necessary to polish the floating surface, but since the materials of the metal film 103 and the slider 101 are different, there is a difference in polishing speed between the two, and in general, compared to the slider 101, there is a difference in polishing speed. The metal film 103, which is made of a soft material, is polished quickly. As a result, it is difficult to form the electrode surface and the floating surface on the same surface, and a step difference δ occurs between them.

FIG. 2 is a sectional view of the conventional magnetic head for measuring the amount of levitation shown in FIG.
Explain. That is, between the floating surfaces 102a, 102b of the slider 101 and the electrode surface 104 formed of the metal film 103, a step difference δ as shown is generated due to the difference in polishing speed. The value of step δ is 0.05
It is small, about μm to 0.2μm, but the floating amount is 0.5μm.
In the case of the following magnetic head, this step difference δ has a great effect on the levitation characteristics. For example, levitation amount 0.35μm
Even when the step difference δ is 0.05 μm, the buoyancy force is reduced by more than 8% compared to the case without the step difference.

In addition, in conventional magnetic heads for measuring the amount of levitation, the surface roughness of the electrode surface is rougher than that of the levitation surface, making it easier for dirt to adhere to it, and the fact that the magnetic disk and magnetic This method has drawbacks such as the electrode surface being easily scratched when sliding in contact with the plating, and furthermore, it is difficult to form a uniform plating film.

In order to eliminate these drawbacks, the present invention forms electrodes on the floating surface using metal sputtering or the like, and covers the electrodes with a protective film made of quartz or the like, and will be described in detail below with reference to the drawings.

FIG. 3 is a perspective view of an embodiment of the present invention seen from the floating surface side, FIG. 4 is a vertical sectional view, FIG. 5 is a lateral sectional view, and FIG. 6 is a lateral sectional view. It is a perspective view seen from the side opposite to a floating surface.

In the figure, 201 is a slider made of a non-conductive material, and 202a, b, and c are slider floating surfaces. The slider 201 is the same as the slider of a magnetic head used in ordinary commercial magnetic disk drives. Reference numeral 203 denotes four thin metal films, such as chromium films with a thickness of about 1 μm or less, which are formed on the slider floating surfaces 202a and 202b by a method such as sputtering. Here, the metal film 203 may cover surfaces other than the floating surface, but it is necessary that the four metal films 203 are not electrically conductive. In this case, only the surface of the metal film present on the floating surface acts as the capacitance electrode surface 204. Furthermore, a protective film 205 made of a hard, non-conductive material such as glass or quartz is placed over the electrode surface 204 and the slider floating surfaces 202a, b, and c by a method such as sputtering, and the surface 206 of this protective film has a mirror surface. Finished with a polished surface. Here, the protective film 205 may cover surfaces other than the floating surface.

Furthermore, in this embodiment, as shown in FIGS. 3 and 5, a thin film 207 of a conductive material such as gold is routed from the slider side surface 208 to the slider back surface 209 by sputtering or the like, and one end of this thin film forms an electrode. The metal film 203 has a structure in which the other end is conductively coupled to a lead wire 210 at the slider back surface 209.

To measure the levitation characteristics using this, the fourth step is
As shown in the figure, move the slider 201 to the magnetic disk surface 2.
11 and measure the capacitance between the electrode surface 203 of the slider and the surface 213 of the conductor 212 in the magnetic disk. In this case, by measuring the capacitance of each of the four electrodes, the gap between the protective film surface of each electrode surface and the magnetic disk surface, that is, the amount of levitation can be determined independently. In other words, not only the minimum levitation amount but also the levitation attitude can be determined. Furthermore, by determining dynamic changes in capacitance, it is possible to measure dynamic changes in the amount of levitation, including the levitation posture.

Next, a method of manufacturing the embodiment shown in FIG. 3 will be described. FIG. 7 is a sectional view showing the manufacturing process of the embodiment of the present invention. To form the structure of this embodiment, as shown in FIG. 7, a solid metal film 203 is formed on the floating surface of the slider 201 by sputtering or the like.
Furthermore, a protective film 205 made of glass or quartz is uniformly applied thereon by sputtering or the like. In this case, the thickness of the protective film 205 is 0.5
The thickness of the protective film should be approximately 1 μm, and the protective film should cover the slider floating surfaces 202a, b, and c.
It does not matter if it covers surfaces other than the floating surface. After that, the protective film 205 is mirror-polished to the AA line and finished as shown in FIG.

As described above, according to the present invention, only the protective film is polished in the final mirror polishing, so that there is no step difference in the floating surface due to the difference in materials as in the conventional method. Furthermore, since the embodiment of the present invention is an ordinary magnetic head without electrodes with a thin film on the order of microns, the external dimensions of this embodiment are within the permissible dimensional tolerances of ordinary magnetic heads. There is no effect of the weight of the added thin film. Therefore, the static and dynamic levitation characteristics of the embodiment of the present invention and an ordinary magnetic head without electrodes are exactly the same, and the levitation characteristics of an ordinary magnetic head can be measured by the embodiment of the invention. I can do it.

In addition, according to the present invention, electrodes and protective films can be formed on the slider of a normal magnetic head by sputtering or other techniques without any processing, and the final mirror finish is also very slight. Since only a small amount of polishing is required, a magnetic head for measuring the amount of levitation can be provided with significantly fewer man-hours than conventional ones.

Further, according to the present invention, when the magnetic head and the magnetic disk come into contact and slide when the magnetic disk starts and stops,
The sliding surface on the magnetic head side is a hard mirror surface made of glass or quartz, so it has very good sliding characteristics, and unlike conventional electrode surfaces, there is no scratching or dirt adhering to them.

As described above, by carrying out the present invention, it is possible to easily provide a magnetic head with electrodes for measuring the amount of levitation that has exactly the same levitation characteristics as a normal magnetic head. As a result, it is possible to completely eliminate the measurement error caused by the difference in levitation characteristics between the conventional magnetic head for measuring the levitation amount and the normal magnetic head in an actual magnetic disk device. Furthermore, the sliding properties are also significantly improved.

Therefore, a magnetic head embodying the present invention can be used not only for testing the levitation characteristics of a magnetic head, but also for testing magnetic disks or magnetic disk devices.

Note that the present invention can be applied to sliders having shapes other than those shown in the embodiments, and the number of electrode surfaces is also arbitrary.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing a conventional magnetic head for measuring levitation, Figure 2 is a sectional view of the magnetic head in Figure 1,
3 is a perspective view of an embodiment of the present invention seen from the floating surface side, FIG. 4 is a vertical sectional view showing the embodiment of FIG. 3 together with a magnetic disk, and FIG. 5 is an embodiment of the embodiment of FIG. 3. 6 is a perspective view of the embodiment of FIG. 3 viewed from the side opposite to the buoyancy surface, and FIG.
It is a sectional view showing the manufacturing process of the embodiment shown in the figure. In the figure, 201 is a slider, 202a,
b, c are slider floating surfaces, 203 is a metal film, 20
4 represents an electrode surface, 205 a protective film, 207 a conductive thin film, and 210 a lead wire.

Claims (1)

[Claims] 1. In a magnetic head that measures the amount of levitation using the capacitance method, an electrode surface is provided on a part of the levitation surface of a slider made of an electrically poor conductor material, and the entire levitation surface including the electrode surface is A floating magnetic head characterized by a structure coated with a protective film made of a hard, electrically poor conductor material with a mirror-polished surface.