JPS6022415B2 - Manufacturing method for magnetic disk media - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a magnetic disk medium having a smooth surface and high signal quality.

In magnetic disk drives, in order to perform recording with a surface density, when a magnetic head that reads and directs signals flies over a magnetic disk medium consisting of a substrate and a magnetic film provided on the substrate, the flying gap is reduced. needs to be made smaller.
Along with this, it has become necessary to improve the surface area of the magnetic disk medium in order to ensure stable flying of the magnetic head. To improve the surface precision of magnetic disk media, it is effective to first smooth the surface of the magnetic disk media substrate (hereinafter referred to as the substrate). Methods such as grinding, lapping and polishing using free abrasive grains are used, and by this method, it is possible to obtain a center line average roughness of 0.02 m or less and a maximum height of 0.2 m or less. ing. However, with the conventional method, tens to hundreds of fine particles remain per surface that cannot be removed even by precision polishing.

The height of this protrusion is approximately 0.2 to 0.5 meters, and even after a magnetic recording medium is formed on the substrate, a protrusion based on this protrusion remains. In general, magnetic heads for high areal density recording have a flying clearance of about 0.2 to 0.5 rm, so if there is even one protrusion, the magnetic head will collide with the protrusion at high speed when the disk is rotating, resulting in serious damage. This causes the problem that the signal cannot be read or written.

In order to completely remove these protrusions, attempts have been made to improve the diamond bite diameter by adjusting the diameter of the diamond bite, using fine free abrasive grains, or increasing the polishing time. Kama's method could not sufficiently reduce the number of protrusions. There is a method of vanishing the surface of the magnetic medium or protective film to remove the protrusions, but this may remove not only the protrusions but also part of the magnetic film or damage the magnetic medium. The disadvantage was that signal errors increased significantly, making it unbearable. The present invention was made to eliminate these conventional drawbacks, and its purpose is to provide a magnetic disk with high signal quality because it has significantly fewer protrusions on the surface and no damage to the magnetic film or protective film. The object of the present invention is to provide a method for manufacturing media with high production efficiency.

In order to achieve such an object, the present invention first detects the number of collisions between protrusions on a substrate and a floating detection head provided on the substrate when manufacturing a magnetic disk medium.
The surface of the substrate is burnish-finished using a burnish head made of a hard material, and then a magnetic film is formed on the substrate.

The present invention will be described in detail below based on examples.

FIG. 1 is an explanatory diagram of an embodiment of the method for manufacturing a magnetic disk substrate according to the present invention.

In the figure, ``1' is a substrate rotating in the direction of the arrow, 2 is a floating vanish head provided so that its grinding part floats on the surface of the substrate 1 with a predetermined flying clearance'' 3
5 is a floating detection head for simultaneously detecting the protrusions present on the surface of the substrate 1; 5 is a sensor for converting the strain stress exerted on the floating detection head 3 due to the collision of the protrusions into an electrical signal; A lead wire, 6 a waveform monitor for observing the output signal from the sensor 4, 7 a comparator that compares the output signal from the sensor 4 with a comparison level and outputs an output when the level of the output signal is higher, 8' This is a counter that is operated based on the output from the comparator 7 and automatically calculates the number of collisions between the protrusion and the floating detection head 3. FIG. 2 is a bottom perspective view of the floating vanish head 2. The floating vanish head 2 in FIG. 1 is shown turned over. 2
Reference numeral 1 denotes a slider as a grinding section made by integrally processing a hard material such as sapphire, and is provided at the tip of a gimbal spring 22 for attitude adjustment.

23 is a load spring for load adjustment.

FIG. 3 is an explanatory diagram of the collision detection operation of the floating detection head, in which a shows an enlarged view of the floating detection head at the time of a collision, and b shows a waveform diagram of the output signal.

In FIG. 3a, 10' is a protrusion formed on the surface of the substrate 1, 31 is a detection slider of the floating detection head 3, and 32 is a protrusion formed on the surface of the substrate 1.
is a gimbal spring that supports the detection slider 31. When the substrate 1 rotates in the direction of the arrow, the protrusion 10 collides with the detection slider 31 floating through a predetermined flying clearance. This collision causes the sensor tortoise shown in FIG. 1 to send out a pulsed output signal. In FIG. 3b, when the protrusion 0 collides with the detection slider 31, a pulse as shown by p is generated between Fujima, and when the level of this pulse p is compared and is higher than that of the bell, the number of collisions is counted. In addition, output level 0
It indicates the noise of the nearby waveform sensor 4 and is set to a value that is sufficiently higher than the noise of the bell signal and lower than the collision detection level. Banish head 2 slider 21
When the flying clearance between the board 1 and the board 1 is set to a predetermined value, and the board 1 is moved in all directions, the slider 21 follows the slight undulations of the board and maintains a constant setting. The entire surface of the substrate 1 is scanned while maintaining a high flying clearance.

If there is a protrusion higher than this floating clearance, the second slider will grind and remove this protrusion. In this embodiment, the number of protrusion collisions is simultaneously detected by the floating detection head 3 in parallel with this grinding work.In this way, the number of protrusion collisions is counted while the protrusion on the substrate surface is being ground. is shown in Fig. 4. Fig. 4 is a graph showing the relationship between the flying clearance of the floating detection head 3 and the number of protrusion collisions. B is the characteristic after performing a vanish finish by setting the bubble height of the floating vanish head 2 to 0.15 mm. The number of collisions has been reduced to a fraction of that of the conventional one.Furthermore, this is the characteristic after the floating vanish head 2 is set to have a flying clearance of 0.1 fm and the vanishing is finished. In the range where the flying clearance of the head 3 is 0.15mm or more, the number of protrusion collisions further decreases to about 1/10.And when the flying clearance of the floating detection head 3 is 0.25mm, the number of protrusions detected decreases. 0
become. After the surface of the substrate 1 is burnished with the floating burnish head 2, a magnetic film is formed on the surface to form a magnetic disk medium, and the surface of this medium is similarly finished smooth with few protrusions.

When a continuous thin film magnetic disk medium made of a magnetic metal film or the like is used, the surface of the medium is formed to follow the surface of the substrate 1, so the surface accuracy of the surface of the substrate 1 is particularly required. FIG. 5 is a rough graph showing the relationship between the flying clearance of the floating detection head 3 and the number of protrusion collisions when such a continuous thin film magnetic disk medium is formed.

In the figure, A indicates the characteristics after forming the medium, and A indicates the characteristics of the substrate burnished under the same conditions as C in FIG. 4. There is almost no difference between the two, and the surface area of the medium surface can be improved to the same extent as that of the substrate surface. In other words, after finishing the board with the floating clearance of the vanishing head set to 0.1 m,
A magnetic disk medium on which a continuous thin magnetic film is formed does not require additional polishing if the magnetic head floating amount is set to 0.25 mm or more. Even when the flying height is set to 0.2 m, the surface of the medium can be easily polished without damaging the magnetic layer. In the present invention, since the number of collisions is automatically measured at the same time as the burnishing of the substrate, there is no need to inspect the smoothness of the substrate surface using another measuring device after finishing, and production efficiency is high.

As explained above, according to the present invention, fine protrusions can be removed by burnishing the substrate surface with a floating burnish head made of a hard material.
By automatically counting this, it is possible to perform the work while observing the burnished finish state, resulting in high productivity and a high area coverage even after the recording medium is formed.

Therefore, the media surface can be polished relatively easily, and the media surface is not damaged. Furthermore, since the floating magnetic head can fly stably without contacting the medium surface, there are many excellent effects such as ensuring high reliability of the magnetic disk device.

[Brief explanation of the drawing]

FIG. 1 shows a method for manufacturing a magnetic disk substrate according to the present invention.
An explanatory diagram of the configuration of the embodiment, Fig. 2 is a downward perspective view of the floating vanish head, Fig. 3 is an explanatory diagram of the collision detection operation of the floating detection head, and Fig. 4 is the relationship between the flying clearance of the floating detection head and the number of protrusion collisions. FIG. 5 is a graph showing the relationship between the flying clearance of the floating detection head and the time of bump collision when a continuous thin film medium is formed. 1... Board, 2... Floating vanish head, 21.
...Slider, 22... Gimbal spring, 23... Load spring, 3... Floating detection head, 4... Sensor, 6... Waveform monitor, 7... Comparator, 8... Force counter. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. While detecting the collision circuit between the protrusion on the substrate and the floating detection head provided on the substrate, the surface of the substrate is burnished using a floating burnishing head made of a hard material, and then a magnetic A method for manufacturing a magnetic disk medium, comprising forming a film.