JP2003132527A - Manufacturing method of magnetic recording medium, method and machine for machining magnetic recording medium base - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording medium at a low cost, which has the recording region only on one surface of a base plate while making an even texture over the whole surface. SOLUTION: The texture working machine 1 is the one used to form a texture only on one surface of the base plate of a magnetic recording medium. It has a grinder unit 4 disposed facing the front surface of the base plate D, a chuck 2 disposed facing the rear surface of the plate D with holes 22 extending axially, a motor M to rotate the chuck 2, and a vacuum pump P connected to the chuck 2. This texture working machine 1 makes a texture only on the front surface of the plate D by grinding it while keeping vacuum at the rear surface of the plate D.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium manufacturing method, a magnetic recording medium substrate processing method, and a magnetic recording medium substrate processing apparatus, and particularly to an external storage device of a computer. The present invention relates to a magnetic recording medium manufacturing method applied to various magnetic recording apparatuses, a magnetic recording medium substrate processing method, and a magnetic recording medium substrate processing apparatus.

[0002]

2. Description of the Related Art Conventionally, an external storage device for a computer is provided with a magnetic recording medium having a disk member made of aluminum (A1) alloy or tempered glass as a substrate. When manufacturing such a magnetic recording medium, first, for example, a nickel-phosphorus (Ni-P) plating film is formed as an underlayer on the substrate surface. A magnetic layer made of chromium (Cr), cobalt (Co) alloy, or the like is continuously formed on the surface of the plating layer, and the surface of the magnetic layer is covered with a carbon-based protective layer. Then, a fluorocarbon-based liquid lubricating layer is formed on the outermost surface. Here, CSS (Cont.
In order to secure durability against act Start Stop, fine roughness called a texture is given. Such a texture reduces the attractive force and frictional force acting between the magnetic head and the medium, so that abrasion and damage are prevented.

Texture processing on the surface of the substrate (surface of the plating layer) is performed using a predetermined texture processing device. First, a conventional texture processing apparatus will be described. This type of texture processing apparatus includes a chuck that clamps a substrate, and the chuck is attached to the tip of a spindle that is rotationally driven by a motor. Further, the texture processing apparatus includes at least one pair of polishing units facing each other with the substrate clamped by the chuck interposed therebetween, and a polishing liquid supply device having a supply nozzle. The polishing unit moves the polishing tape wound around the contact roller and moves the polishing tape closer to and away from the substrate.

Using such a texture processing device,
When performing texture processing on the substrate surface, first, on the chuck attached to the tip of the spindle, the inner circumference of the opening provided in the center of the substrate or a region around the opening with a width of about 1 mm. To hold. Then, the motor is operated to rotate the substrate, and the polishing tape wound around the contact roller is pressed against the front and back surfaces of the substrate. Further, at this time, a polishing liquid as a coolant is dropped from the supply nozzle between the substrate and the polishing tape.

[0005]

By the way, in recent years,
The high recording density of magnetic recording media has been advanced,
The storage capacity that could not be obtained without using both the front and back sides (2 heads) of one medium is one side (1 head) of one medium.
It is becoming available only by yourself. Along with this, a low-cost one-head external storage device, etc., which is targeted at the so-called low-end market, has also appeared. Further, in recent years, the use of magnetic recording devices has been diversified, and as one example, magnetic recording devices for home appliances are being developed. Even in this type of recording device, the recording area is only on one side. There is a demand for a magnetic recording medium having a magnetic recording medium or a magnetic recording medium having no opening. For these reasons, a magnetic recording medium having a recording area on only one side of a substrate can be manufactured at low cost (about one half of the conventional one) at a low cost regardless of the presence or absence of an opening and the presence or absence of a boss for incorporating a drive. It is required to provide.

However, in the case where an attempt is made to obtain a magnetic recording medium having a recording area on only one side of the substrate through the conventional texturing method as described above, the following problems occur. That is, when performing texture processing while holding the inner circumference of the opening of the substrate on the chuck, the substrate comes off the chuck during processing due to the polishing unit pressing the surface of the substrate to be processed. That trouble occurs frequently. On the other hand, when the chuck holds a region having a width of about 1 mm around the opening, the problem that the substrate is detached from the chuck is avoided, but the outer peripheral side of the substrate pressed by the polishing unit is curved toward the chuck, It becomes difficult to perform uniform texture processing on the entire surface from the inner peripheral side to the outer peripheral side of the surface to be processed. Such a trouble in texture processing is one obstacle to providing a magnetic recording medium having a recording area on only one side at low cost.

Therefore, the present invention is capable of imparting a uniform texture to only one side of the substrate, which contributes to the realization of a magnetic recording medium having a recording area on only one side at low cost. And a method for processing a substrate for a magnetic recording medium, and an apparatus for processing a substrate for a magnetic recording medium.

[0008]

A method of manufacturing a magnetic recording medium according to the present invention according to claim 1 is a method of manufacturing a magnetic recording medium having a recording area on a front surface of a substrate, while holding a back surface of the substrate in vacuum. This includes the step of performing texturing only on the surface of this substrate.

That is, this method includes a step of applying a texture only to the front surface of the substrate by a polishing unit or the like while holding the back surface of the substrate in vacuum by using a vacuum chuck or the like. Thus, during processing, the vacuum holding position, the number of holding positions, the area, etc. can be set so as to sufficiently resist the pressing force applied to the substrate by the polishing unit or the like that gives a texture to the surface to be processed. It is possible to appropriately and arbitrarily select within the range of the back surface of the substrate to be held. Therefore, according to such a method, it is possible to always maintain the substrate in a flat state without warping during texturing. As a result, by using this method, it is possible to give a uniform texture to only one side of the substrate, and a magnetic recording medium having a recording area on only one side can be realized at low cost.

Further, this method can be applied not only to a substrate having an opening in the center, but also to a substrate having no opening or a substrate having a boss for incorporating a drive in the center of the back surface. is there. And in these cases, it is preferable that the substrate is made of a glass material.

According to a fifth aspect of the present invention, there is provided a method of processing a magnetic recording medium substrate, wherein the magnetic recording medium substrate is processed to impart a texture to the surface of the magnetic recording medium substrate.
It is characterized in that only the front surface of the substrate is polished while the back surface of the substrate is held in vacuum.

According to a sixth aspect of the present invention, there is provided a magnetic recording medium substrate processing apparatus which is a magnetic recording medium substrate processing apparatus for imparting a texture to a magnetic recording medium substrate surface. Polishing means arranged on the back surface side of the substrate, a chuck portion having a plurality of holes extending in the axial direction of the substrate, a driving means for rotating the chuck portion, and a vacuum suction means connected to the chuck portion. It is characterized by including.

In this magnetic recording medium substrate processing apparatus,
The chuck section and the vacuum suction means function as a so-called vacuum chuck. That is, in this processing apparatus, the substrate is held by lowering the pressure inside the plurality of holes by the vacuum suction means while the substrate is in contact with the end surface of the chuck portion. With this, by appropriately setting the number, cross-sectional area, positions, etc. of the holes to be arranged in the chuck portion according to the target substrate, a polishing unit or the like that gives a texture to the surface to be processed during processing. It is possible to sufficiently resist the pressing force applied from the to the substrate. Therefore,
By using this processing apparatus, not only a substrate having an opening in the center, but also a substrate having no opening or a substrate having a boss for incorporating a drive in the center of the back surface,
During processing, it can always be kept flat without warpage. As a result, by using this processing apparatus, it is possible to give a uniform texture to only one surface of the substrate, and thus it is possible to realize a magnetic recording medium having a recording area on only one surface at low cost.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a method for manufacturing a magnetic recording medium, a method for processing a substrate for a magnetic recording medium, and an apparatus for processing a substrate for a magnetic recording medium according to the present invention will be described in detail below with reference to the drawings. .

FIG. 1 is a schematic configuration diagram showing a magnetic recording medium substrate processing apparatus according to the present invention. The texture processing apparatus 1 shown in FIG.
It is used for imparting texture in order to secure durability against SS. For this reason, the texture processing apparatus 1 includes the chuck unit 2 that holds the substrate D. The chuck portion 2 is fixed to the tip of a spindle 3 which is rotationally driven by a motor M. Further, the texture processing apparatus 1 has a polishing unit 4 and a polishing liquid supply device including a supply nozzle 5 (all are not shown).

The polishing unit 4 includes a contact roller 4
1, a polishing tape 42, a drive mechanism, a moving mechanism, etc., which are not shown, and are arranged so as to face the substrate D held by the chuck portion 2. The polishing unit 4 moves the polishing tape 42 wound around the contact roller 41 and the like by a driving mechanism and moves the polishing tape 42 toward and away from the substrate D by a moving mechanism. In addition to the supply nozzle 5, the polishing liquid supply device includes a polishing liquid tank, a supply pump, etc., all of which are not shown in the drawing. Between the polishing tape 42 of the polishing unit 4 and the substrate D, a diamond slurry, etc. The polishing liquid S is dropped.

Although only one polishing unit 4 is shown in FIG. 1, the texture processing apparatus 1 is provided with two polishing units 4. A polishing tape 42 for rough grinding is attached to one polishing unit 4, and a polishing tape 4 for finish grinding is attached to the other polishing unit 4.
2 is attached. As a result, in the texture processing device 1, the polishing process is performed in two stages. That is, in the first step, one of the polishing units 4 is used to perform rough grinding so that the center line average roughness of the substrate D is about several tens of liters. Then, in the next step, the abnormal projection or the like generated in the previous step is removed by using the other polishing unit 4.

The chuck portion 2 included in the texture processing apparatus 1 is formed as a cylindrical member made of metal or the like, and has a diameter slightly smaller (substantially the same) than the outer diameter of the substrate D to be processed. . Further, the end surface of the chuck portion 2 opposite to the motor M is formed flat so as to hold the substrate D. As shown in FIGS. 1 and 2, a hole portion 21 is formed in the central portion of the chuck portion 2. It is preferable that the inner diameter of the hole 21 is set larger than the outer diameter of the boss portion for incorporating the drive which may be formed at the center of the back surface of the substrate. Further, the chuck portion 2 has a structure shown in FIG.
As shown in FIG. 5, a large number of holes 22 extending in the axial direction are radially formed.

That is, as shown in FIG. 2, a plurality of holes (22) are arranged at a predetermined interval on a radius equally divided by a predetermined angle. In this embodiment, as shown in FIG. 2, by further forming two holes 22 between the four holes 22 so as to be located on the outer peripheral side of the chuck 2, The arrangement density of the holes 22 on the outer peripheral side of 2 is higher than that on the inner peripheral side. As shown in FIG. 2, the vacuum pump P is connected to the chuck portion 2 configured as described above through an appropriate connecting portion and sealing portion (neither is shown). The vacuum pump P communicates with each hole 22 (and the hole 21), and sucks vacuum (reduces the pressure) inside each hole 22.

Next, a method of manufacturing a magnetic recording medium having a recording area on only one side while imparting a texture to the substrate surface by the above-described texture processing apparatus 1 will be described.

In this case, first, for example, a nickel-phosphorus (Ni-P) plating film having a film thickness of about 10 μm is formed on the surface of the substrate D as a base layer. Here, the substrate D is
The substrate having the opening Dh in the central portion (see FIG. 1) may be a substrate having no opening, or a substrate having a boss portion for incorporating a drive in the central portion of the back surface. In these cases, the substrate D is preferably made of a glass material. Once the plating layer is formed on the surface of the substrate D, next, using the above-described texture processing apparatus 1,
Texture is applied to the surface of the substrate D, that is, the surface of the plating layer. By thus forming the texture on the surface of the plating layer, the attractive force and the frictional force acting between the magnetic head and the medium are reduced, so that abrasion and damage are prevented.

Here, in the above-described texture processing apparatus 1, the chuck portion 2 and the vacuum pump P as the vacuum suction means.
Function as a so-called vacuum chuck. That is, when holding the substrate D on the chuck portion 2, the back surface of the substrate D (the surface opposite to the plating layer, that is, the surface on which the recording area is not formed) is brought into contact with the end surface of the chuck portion 2. The vacuum pump P is operated.

As a result, the pressure in the many holes 22 is reduced by the vacuum pump P, so that the substrate D is sucked and held by the chuck 2. When processing a substrate having a boss for incorporating a drive in the center of the back surface, the boss is inserted into the hole 21 and the flat back surface located outside the boss is chucked. The chuck portion 2 is vacuum-held while being in contact with the end surface of the portion 2.
From this state, the motor M is operated to rotate the substrate D, and the polishing tape 42 wound around the contact roller 41 is pressed against the surface of the substrate D. Further, at this time, the polishing liquid S is dropped from the supply nozzle 5 between the surface of the substrate D and the polishing tape 42.

As described above, according to the present invention, the number of holes 22 arranged in the chuck portion 2, the cross-sectional area of each hole 22, the arrangement position, etc. are appropriately set according to the target substrate D. By doing so, it becomes possible to sufficiently resist the pressing force applied to the substrate D from the polishing unit 4 that gives a texture to the surface to be processed during processing. Therefore, if the texture processing apparatus 1 is used, not only the substrate D having an opening in the center, but also a substrate having no opening or a substrate having a boss for incorporating a drive in the center of the back surface is used. During processing, it can always be maintained in a flat state without warpage. As a result, if the texture processing apparatus 1 is used, it is possible to apply a uniform texture to one side (front surface) of the substrate D, and the textured substrate D is applied.
The yield can be improved.

When the diameter or the like of the substrate D to be processed by the texture processing apparatus 1 varies, it is possible to sufficiently resist the pressing force applied from the polishing unit 4 to the substrate during processing. In addition, it suffices to prepare a plurality of chuck portions whose positions for vacuum holding, the number of holding positions, the cross-sectional area of the holes, etc. are appropriately and arbitrarily selected within the range of the back surface of the substrate to be held. Also in this case, in order to effectively prevent the outer peripheral side of the substrate D pressed by the polishing unit 4 from bending toward the chuck side (motor M side), the arrangement of the hole portions 22 on the outer peripheral side of the chuck portion 2 is performed. It is preferable to increase the installation density.

After that, the textured substrate D
A magnetic layer made of chromium (Cr), cobalt (Co) alloy, or the like is continuously formed on the surface of the (plating layer).
The surface of the magnetic layer is covered with a carbon-based protective layer. Then, a fluorocarbon-based liquid lubricating layer is formed on the outermost surface to complete the magnetic recording medium. As described above, according to the present invention, since the yield of the textured substrate D can be improved, the magnetic recording medium having the recording area on only one side can be realized at low cost.

FIG. 3 and FIG. 4 show the results of measuring the center line average roughness Ra of a substrate textured by the method for processing a magnetic recording medium substrate according to the present invention.

FIG. 3 shows an embodiment 1 in which the chuck 2 is textured while the back surface of the substrate is held in vacuum (FIG. 3).
FIG. 4 is a table comparing EX1) in FIG. 3 with a comparative example (R in FIG. 3) in which a conventional chuck is textured while holding a region around the opening of the substrate having a width of about 1 mm. In Example 1 (EX1), a glass substrate having a diameter of 2.5 inches (63.5 mm) having an opening at the center was held by the chuck portion 2 in vacuum, and the substrate was moved to 300 r.
It was rotated at pm. Then, while the polishing tape 42 made of a woven fabric made of polyester ultrafine fiber is fed at a speed of 60 mm / min, a pressing force of 0.85 kgf / cm ² (8.33 × 10 ⁴ N /
m ² ) and pressed against the surface of the substrate. Furthermore, a diamond slurry having an average particle size of 0.2 μm was dropped from the supply nozzle 5 between the substrate surface and the polishing tape 42. Comparative Example (R) was carried out under the same conditions as in Example 1 except for the method of holding the substrate. The centerline average roughness Ra after processing is measured by A
FM (Atomic Force Microscop)
e).

As can be seen from the results shown in FIG. 3, when the substrate is chucked by the conventional method, the polishing unit presses the substrate so that the outer peripheral side of the substrate is curved toward the chuck side. It gradually decreases from the center toward the outer peripheral side, and a uniform center line average roughness Ra is not obtained as a whole. On the other hand, when the substrate is vacuum-held on the chuck portion 2 as in the present invention (Example 1), the center line average roughness Ra is almost constant from the center side to the outer periphery, and a uniform texture is obtained throughout. You can see that it has been obtained.

FIG. 4 shows an example 2 (EX2 in FIG. 4) in which the back surface of the substrate having no opening is textured while the chuck part 2 is held in vacuum, and a substrate having a boss part in the center. Example 3 (EX in FIG. 4) in which texture processing was performed while the back surface was held in the chuck portion 2 in vacuum.
3) and.

In Example 2, a glass substrate having a diameter of 1 inch (25.4 mm) having no opening was held in the chuck portion 2 in vacuum, and the substrate was rotated at 600 rpm. On the other hand, in Example 3, with the boss portion inserted in the hole portion 21 of the chuck portion 2, the diameter is 1 inch (25.4 mm).
The substrate was rotated at 600 rpm while the glass substrate with a boss of No. 2 was vacuum-held on the chuck portion 2. Then, in both Example 2 and Example 3 (EX2, EX3), while the polishing tape 42 made of a woven fabric made of polyester ultrafine fiber was fed at a speed of 60 mm / min, the rubber altitude 6
Pressing force is 0.5 kgf / cm ² via the pressing member of 0 °
It was pressed against the substrate surface with (4.9 × 10 ⁴ N / m ² ).
Furthermore, a diamond slurry having an average particle size of 0.2 μm was dropped from the supply nozzle 5 between the substrate surface and the polishing tape 42. AF of the centerline average roughness Ra after processing is measured by AF.
Made by M.

As shown in FIG. 4, by holding the substrate on the chuck portion 2 in vacuum, both the second embodiment and the third embodiment, that is, both the substrate having no opening and the substrate having the boss portion. It can be seen that the centerline average roughness Ra is almost constant from the center side to the outer periphery, and a uniform texture is obtained as a whole. Since the peripheral speed of the rotating substrate is slightly reduced on the inner peripheral side, the roughness tends to be slightly increased as compared with the outer peripheral side as shown in FIG. 4, but this is practically within an allowable range. It is in.

[0033]

According to the present invention, while the back surface of the substrate for the magnetic recording medium is held in vacuum, only the front surface of this substrate is textured, that is, polished, so that only one surface of the substrate is processed. As a result, a uniform texture can be applied to the entire surface, and a magnetic recording medium having a recording area on one side can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an apparatus for processing a magnetic recording medium substrate according to the present invention.

2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a chart showing the measurement results of the center line average roughness in a substrate textured by the method for processing a magnetic recording medium substrate according to the present invention.

FIG. 4 is a chart showing the measurement results of the center line average roughness in a substrate textured by the method for processing a magnetic recording medium substrate according to the present invention.

[Explanation of symbols]

1 Texture processing device 2 Chuck part 3 spindles 4 polishing unit 5 supply nozzles 21 hole 22 holes 41 Contact roller 42 polishing tape D board Dh opening M motor P vacuum pump S polishing liquid

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takeshi Murakami             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5D112 GA09

Claims (6)

[Claims] 1. A method of manufacturing a magnetic recording medium having a recording area on the front surface of a substrate, comprising the step of performing texture processing only on the front surface of the substrate while holding the back surface of the substrate in vacuum. 2. The method of manufacturing a magnetic recording medium according to claim 1, wherein a substrate having no opening is used as the substrate. 3. The method of manufacturing a magnetic recording medium according to claim 1, wherein a substrate having a boss portion for incorporating a drive in a central portion of a back surface is used as the substrate. 4. The method for manufacturing a magnetic recording medium according to claim 1, wherein a glass material is used as the substrate. 5. A method for processing a magnetic recording medium substrate for imparting a texture to the surface of a magnetic recording medium substrate, wherein only the front surface of this substrate is polished while the back surface of the substrate is held in vacuum. A method for processing a substrate for a magnetic recording medium, characterized in that. 6. A magnetic recording medium substrate processing apparatus for imparting a texture to a magnetic recording medium substrate surface, comprising: a polishing means arranged on the front surface side of the substrate; and a rear surface side of the substrate. A chuck unit having a plurality of holes extending in the axial direction thereof; a driving unit for rotating the chuck unit; and a vacuum suction unit connected to the chuck unit. Processing equipment.