JPS62203748A - Machining method for magnetic disc substrate - Google Patents

Abstract

PURPOSE:To provide a magnetic disc substrate which is excellent in lubricity and decreased in a recording error, by a method wherein, after fine ruggednesses are formed on a magnetic disc substrate surface by the use of a lapping film, the substrate is ground by means of a grinding tool having a specified Young's modulus. CONSTITUTION:After fine ruggednesses are formed on a magnetic disc substrate surface by means of a lapping film, through grinding of the whole of a substrate surface, machining chips firmly adhered to the substrate surface are removed in a condition that the fine ruggednesses remain. Fine free grinding grains located between a grinding tool and the substrate are moved relatively with each other, and the substrate surface is ground to remove the adhered machining chips. In this case, when a grinding tool having a high Young's modulus is used, the fine ruggednesses formed on the substrate surface by the lapping film are also removed togetherwith the machining chips, but when a grinding tool having low Young's modulus of 1X10<2>g/mn<2> or less is used, only the machining chips can be removed in a state that the fine ruggednesses on the substrate surface remain. This machining method produces an excellent effect in that a recording error is decreased, a magnetic head is inhibited against adsorption, and lubricity is excellent.

Description

[Detailed Description of the Invention] [Industrial Application Separation] The present invention relates to a method for processing a magnetic disk substrate, and particularly to a method for processing a magnetic disk substrate such as a high-density magnetic disk substrate (for example, a method for processing a thin film medium magnetic disk by plating or sputtering method). substrate)
[Prior art] In general, magnetic disk media using magnetic thin films are sensitive to the magnetism generated when starting and stopping devices. In order to withstand contact with the vehicle, it is necessary to have the characteristics of the vehicle, the vehicle, and the vehicle. For this reason, a 5i01 film is provided as a retaining film on the magnetic thin film formed on the magnetic disk substrate surface, and a liquid or solid lubricant is applied to the surface of the retaining film to improve the lubrication performance. etc. have been done.

For this magnetic disk substrate, an aluminum alloy surface, a metal key formed on an aluminum alloy surface, or an anodized surface formed on an aluminum alloy surface is processed with the required precision of 1fK, corresponding to the elms of the recording medium. is used.

If the surface roughness of the magnetic disk surface is finished to be very small (50X), the magnetic field will be attracted to the surface of the magnetic disk.

As a solution to this problem, the inventors K proposed a method for processing magnetic disk substrates (Patent No. 59-150582
).

That is, this processing method is characterized by bringing the surface of a rotating magnetic disk substrate into processing contact with a wrapping film held by an elastic body to form fine irregularities on the surface of the magnetic disk substrate. When fine irregularities with a depth of 150X are formed on the surface of the magnetic disk substrate, the magnetic
This prevents adsorption of the card. However, it has been found that this method has a problem in that there are many recording errors after the magnetic thin film is formed on the substrate surface.

[Problem that the invention seeks to solve]

In the above-mentioned method of processing a magnetic disk substrate, the surface of the magnetic disk substrate is processed! When fine irregularities were formed, it was thought that fine cutting debris from the abrasive grains of the lapping film remained on the substrate surface, causing recording errors. In this substrate processing method, most of the processing debris is discharged by the centrifugal force caused by the rotation of the magnetic disk substrate, but processing debris that is strongly attached to the surface of the magnetic disk substrate remains without being discharged.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic disk substrate machining method that solves the problems caused by conventional magnetic disk substrate machining methods, has excellent lubricity, and significantly reduces recording errors.

[Child actor to solve problems]

According to the method of the present invention, after forming fine irregularities on the surface of a magnetic disk substrate using a lapping film, the Young's modulus becomes l.
A method for processing a magnetic disk substrate is obtained, which is characterized by polishing the substrate using the following polishing tool ◇ [Example] Examples of the present invention will be described below with reference to the drawings. do.

FIG. 1 shows the results obtained according to one embodiment of the invention.

The magnetic disk substrate used in this example was an aluminum alloy plate with N1-P holes and holes applied thereto. This magnetic disk substrate was rotated at high speed (1000 rpm), and a lapping film (diamond abrasive grains 3 μm) was brought into contact (pressure 5 g/cIrL) with the rotating substrate surface to form fine irregularities (depth 200×) on the substrate surface. do.

Next, the magnetic disk substrate on which fine irregularities are formed has a Young's modulus of E
Three elliptical polishing tools with different values (Es = 5 x ] O
gA′IIL2. E go = I X 102g/CR2
, BH = I
．． The relative speed was IQm/mil, the machining time was 1m1n, and the free abrasive grains used were silicon dioxide fine particles (0.01μm).The results of polishing in this way were as shown in Figure 1. In both cases, processing debris on the substrate surface was removed, and recording errors were significantly reduced (by about 1/10). However, a polishing tool with a large Young's modulus (E, = I XI 0
3g/c! In IL2), when a substrate on which fine irregularities have been formed using a pin film is polished, even the fine irregularities are removed, and there is a drawback that the magnetic head is attracted to the disk surface. On the other hand, -? 7 Polishing tool with small grating rate (E
t = 5 x 10 g/cIIL-E snow = 1 x 1
02g/cTIL2)
Only one piece of debris is removed, and most of the fine irregularities remain, making them magnetic.

It was possible to prevent the adsorption of

In this example, after forming fine irregularities on the surface of a magnetic disk substrate using a wrapping film, the entire surface of one substrate is polished to remove processed debris strongly adhered to the substrate surface while leaving the fine irregularities formed. It is something. Microscopic free abrasive grains interposed between the polishing tool and the substrate surface are moved relative to each other by the rotation of the polishing tool, and the substrate surface can be polished to remove attached machining debris.

In this case, if a polishing tool with a high Young's modulus is used for polishing, the fine irregularities on the substrate surface imparted by the ping film will be removed along with the processing debris, but if polishing is performed using a polishing tool with a low Young's modulus. can remove only the processing debris, leaving only fine irregularities on the substrate surface. This is thought to be because when using a polishing tool with a small Young's modulus, the polishing tool follows the minute irregularities on the substrate surface while polishing. Therefore, processing debris strongly attached to the magnetic disk substrate surface is the cause of the recording process 2-. can solve problems.

In addition, in one embodiment of the present invention, 2. Although a pink film was used, a lapping film of aluminum oxide abrasive grains or silicon carbide abrasive grains may also be used. Although silicon dioxide fine particles (0.01 μm) were used as polishing free abrasive grains to polish the substrate, aluminum oxide fine particles, silicon carbide fine particles, and diamond fine particles may also be used. [Effects of the Invention] As described above. As can be seen, the processing method of the present invention has the effect of reducing recording errors and having excellent lubricity in that magnetic fields do not attract magnets.

[Brief explanation of drawings]

Claims (1)

[Claims] After forming fine irregularities on the surface of the magnetic disk substrate using a wrapping film, the Young's modulus is 1 x 10^2 g/mm.
A method for processing a magnetic disk substrate, comprising polishing the magnetic disk substrate using a polishing tool of ^2 or less.