JPH05128509A - Manufacture of recording medium - Google Patents

Abstract

PURPOSE:To easily change over the manufacturing operation of recording media whose size and shape are different and to enhance the production efficiency of the recording media by a method wherein a large-sized magnetic recording base material is cut out to the recording media whose size and shape are as desired by using a laser, ultrasonic waves, an electric discharge machining method or the like. CONSTITUTION:A magnetic recording medium 1 is formed on the whole surface of a large-sized substrate; it is held inside a fixation device 2. Then, a laser beam 3 is oscillated by using, e.g. a carbon dioxide laser or a high-accuracy working machine 4; magnetic recording media 5 whose size and shape are as desired are cut out individually. In this manner, the recording media can be manufactured after they have been cut and worked to desired shapes and sizes as intended. Thereby, various kinds of good-quality recording media whose sizes are different can be manufactured with good efficiency, and the industrial manufacturing method of recording media can be achieved with high production efficiency the smaller their size is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium such as a magnetic recording medium, an optical recording medium and a magneto-optical recording medium, and more particularly to a method for efficiently manufacturing a small magnetic recording medium.

[0002]

2. Description of the Related Art In recent years, with the spread of personal computers and optical recording devices, the demand for recording media is rapidly increasing.
These devices are downsized and lightened so that more information can be processed. Along with this, with the rapid increase in demand for recording media built into these devices, there is a strong demand for higher recording density, and there is an increasing demand for downsizing and thinning. Therefore, there is a strong demand for a method of economically manufacturing a large amount of smaller recording media.

Generally, in the method of manufacturing a recording medium, the substrate is preliminarily punched, cut out by a mechanical method such as cutting, surface-treated such as Ni-P plating, and further surface-polished to finish the surface smoothly. Then, a recording layer is formed on the substrate by a method such as plating or sputtering, and a protective layer is further formed thereon. In particular, a method of manufacturing a magnetic recording medium by a sputtering method, which has become popular in recent years, is performed as follows. That is, a non-magnetic substrate processed into a predetermined size and shape is plated with Ni-P, and the surface is smoothed by polishing to form unevenness called a texture. afterwards,
First, a base layer is formed by a sputtering method, and then a magnetic layer and a protective layer are formed in that order to form a recording medium.

[0004]

As described above, according to the conventional method, the recording medium substrates are prepared in advance by machining, and the recording medium substrates are polished and textured one by one, and then the recording layer is formed. However, as the size of the board becomes smaller, it becomes necessary to miniaturize and precisely machine the board mounting portion of these processing devices. Next, when the substrate is mounted on the support in the process of forming the recording layer, for example in the sputtering process, the robot automatically mounts it, but the precision is required for the mounting. To do.

Further, it is time-consuming to mount the device, which is a major factor of cost increase. Furthermore, in order to manufacture various sizes and shapes, it is necessary to replace the jigs attached to each device and change the setting of manufacturing conditions through the film forming process of each layer including polishing, texture and recording layer. Therefore, there has been a problem that the operating rate of the device is lowered and the production efficiency is lowered.

[0006]

That is, the present invention is summarized as follows. A large-sized substrate having an area capable of holding a plurality of recording media is used, the surface of the large-sized substrate is subjected to finishing treatment, at least a recording layer and a protective layer are formed, and then the plurality of recording media are cut into desired dimensions. A method of manufacturing a recording medium, which is characterized in that the recording medium is formed. Further, in particular, the recording medium is a magnetic recording medium, the material of the large substrate is glass, the method of cutting into a desired size and shape is a method by laser, ultrasonic waves, electric discharge machining or mechanical cutting A method of manufacturing a recording medium.

The present invention will be described in more detail below. Large-sized substrates used in the present invention are usually aluminum, aluminum alloys, NiFe-based, FeAl-based, Mn.
It is preferable to use a soft magnetic alloy having high magnetic permeability such as Zn ferrite, glass, ceramics, polycarbonate, or the like, which has high hardness, can easily provide smoothness, and has excellent corrosion resistance. In the case of an optical recording medium or a magneto-optical recording medium, resin such as polycarbonate or glass is used.

When the recording medium is an optical recording medium, a resin such as polycarbonate or glass is used for the large substrate, and a thin film material such as a Te-based alloy is formed for the recording layer by a sputtering method or a vapor deposition method. In the case of a magneto-optical recording medium, TbFeCo-based, G
The dFeCo-based and NdFeCo-based thin films are formed by the sputtering method or the vapor deposition method as in the case of the optical recording medium.

The present invention will be described by way of an example in which a magnetic recording medium is produced by using aluminum as a large substrate. First, a large aluminum substrate having a size capable of cutting out a large number of media having a desired size and shape is used. Then, a Ni-P alloy plating film or a NiFe-based soft magnetic alloy plating film is formed on the surface thereof. When the material of the large substrate is a soft magnetic alloy, it is not necessary to form a plating film. Prior to forming each constituent layer mainly composed of a magnetic layer on this large-sized substrate, its surface is subjected to finishing treatment. The finishing treatment here is to form irregularities having a maximum roughness (R _max ) of 1 to 30 nm and an average roughness (R _av ) of about 1 to 3 nm on the surface of this substrate by a chemical method, a mechanical method or the like. It is to be.

As a chemical method, for example, the surface of a large aluminum substrate is anodized to form alumite and small holes are formed, and a nonmagnetic NiCu alloy is electrodeposited into the holes, followed by phosphoric acid or chromic acid solution. There are a method of finishing treatment after etching in the inside, and a method of finishing treatment by immersing a large glass substrate in a hydrofluoric acid-based solution. By these finishing treatments, the surface has R _{max of} 5 to 30.
nm, R _{av of 1 to} 3 nm is formed. In addition, it is not necessary to be limited to these as long as the surface unevenness treatment as described above can be performed by the chemical treatment. Also,
It is also possible to finish with gas, plasma or ion etching.

As a mechanical method, there is a method of polishing by using abrasive grains such as diamond and alumina, and the above-mentioned unevenness is formed on the surface of the substrate. This is what is commonly referred to as texturing.

A detailed description will be given below with reference to FIGS. In the case of a magnetic recording medium by the plating method, a magnetic alloy film such as CoP or CoNiP is formed on the large-sized substrate thus finished by the plating method.In the case of the magnetic recording medium by the sputtering method, chromium or titanium is used. Nonmagnetic layer of metal or alloy such as Ni or Fe or soft magnetic underlayer of Ni-Fe is formed and CoNiCr, CoCr, CoCrTa, CoCrP
A magnetic alloy film of t, CoNiPt, etc. is formed.

The large-sized substrate 11 thus finished is mounted on the carrier 10, and the underlayer, the magnetic layer and the protective layer are sputtered in this order for continuous manufacture. According to the conventional method shown in FIG. 4, the support 12 for the substrate 15 having a desired size and shape is used.
It was necessary to precisely mount the robot 14 on each holding portion 13 of the support base having high dimensional accuracy, but in the present invention, since only one large substrate is held, a simple apparatus can be used easily in a short time. It can be carried out.

Further, in the case of the conventional method of using a supporting base, the sputtering base of these layers and impurities such as water molecules adsorbed thereto adhere to the supporting base. Although there is a problem that impurities deteriorate the quality of the magnetic recording medium, in the present invention, a necessary portion is cut out from the magnetic recording medium base material on which a necessary layer including a magnetic layer is formed on a large substrate. Since the magnetic recording medium is produced and the rest is not discarded and recycled and returned to the inside of the sputtering apparatus, a good quality magnetic recording medium can be produced with a good yield without the above problems.

From the magnetic recording medium base material having the underlayer, the magnetic layer and the protective layer thus formed, a large number of magnetic recording media having desired dimensions are laser-cutting machine, ultrasonic machining machine, electric discharge machine or Cut out with a mechanical cutting machine.
FIG. 1 shows the case of cutting with a laser cutting machine. Magnetic recording medium base material 1 on which a magnetic recording layer and a protective layer are formed
Is attached to the fixing device 2 for fixing and holding. The magnetic recording medium base material 1 can be fixed in either the horizontal direction or the vertical direction.

Next, the laser 3 is emitted from the laser generator 4.
The magnetic recording medium 5 having a desired size and shape is cut out according to the programmed size and position of the cutout. The cut surface of the disk-shaped magnetic recording medium cut out by the laser is cut by the laser light at a local high temperature in a short time, the dimensional accuracy and surface condition are good, and the recording layer is protected without being affected by the laser. Since the layer has no thermal or mechanical strain, a good quality product can be obtained.

Here, even if a ultrasonic cutting machine, an electric discharge machine, or a mechanical cutting machine equipped with a cutting tool is used instead of the laser cutting machine, magnetic recording having a desired size and shape can be easily performed as in the case of laser cutting. The medium can be cut out. In the case of using an ultrasonic machine or an electric discharge machine, hold the base material with the recording layer and the protective layer on the fixing device as in the case of the laser cutting machine, and use the ultrasonic machine or the electric discharge machine, respectively. A magnetic recording medium having a desired size and shape can be cut out. If the large substrate is non-conductive, the electric discharge machine cannot be used. When using a mechanical cutting machine equipped with a cutting tool, the cutting tool is usually made of an abrasive such as diamond, cubic boron nitride or other cemented carbide material.

After the magnetic layer and the protective layer are formed on one large substrate in this way to form a large magnetic recording medium base material,
When cutting out a large number of magnetic recording media having a desired shape, it is possible to prepare a magnetic recording medium base material having the same size as a support table on which 16 3.5-inch substrates can be mounted. From 3.5 to 3.5 inch magnetic recording media
It is possible to cut out one magnetic recording medium, 49 2.5-inch substrates and 100 2-inch substrates.

In the case of the magnetic recording medium by the plating method, after the texturing process, the chromium underlayer is not formed,
After forming the magnetic recording layer by the plating method, the protective layer is formed to prepare the magnetic recording medium base material, and the magnetic recording medium is cut out by the above-mentioned method. The recording medium is an optical recording medium,
The same applies to the case of the magneto-optical recording medium as the case of the magnetic recording medium.

[0020]

According to the present invention, a method for producing a large-sized magnetic recording medium base material in which at least a recording layer, a protective layer and the like are previously formed on a large-sized substrate and then performing laser, ultrasonic wave, electric discharge machining or mechanical cutting By cutting by
Since it is possible to accurately cut out a recording medium having a desired size and shape in a short time, it is easy to switch back and forth between products of different sizes and shapes, and it is possible to efficiently produce a small size recording medium.

[0021]

Example 1 An example of the present invention will be specifically described. Prepare a large-sized substrate by preparing smooth crystallized glass with a length of 500 mm, a width of 500 mm and a thickness of 1.27 mm. This was immersed in a hydrofluoric acid-based solution to form irregularities with R _{max of} 20 nm and R _{av of} 3 nm on the surface. This large-sized substrate is mounted on a carrier, and a continuous sputtering device is used to form chromium as an underlayer, CoCrPt as a magnetic layer, and a carbon protective layer to form a magnetic recording medium on the entire surface of a large-sized magnetic recording medium. A medium base material was obtained.

This large-sized magnetic recording medium base material is held in the fixing device 2 shown in FIG. 1, and a laser cutting machine (manufactured by Mitsubishi Electric Corporation, carbon dioxide gas laser, high precision processing machine (ML12
12HB1, cutting oscillator 3016S), oscillates a laser beam, 3.5 inch medium with outer diameter 95 mm, inner diameter 25 mm, 2.5 inch medium with outer diameter 65 mm, inner diameter 20 mm, outer diameter 48 mm, inner diameter 12 mm 2 Each inch magnetic recording medium was cut out. The cutting speeds were 226, 160 and 113 seconds, respectively.

The number of magnetic recording media that can be mounted on the support or the number of magnetic recording media that can be cut out from the size of a large substrate is shown in Table 1 as the production amount. The yield indicates the ratio of the actually manufactured magnetic recording medium to the number of magnetic recording media that can be cut out from the size of a large substrate that can be mounted on a support. With respect to the magnetic characteristics, five magnetic recording media were taken out from the number of sheets per carrier, and the coercive force was measured by a sample vibrating magnetometer. The results are also shown in Table 1, which was good at 1070 to 1100 Oe.

[0024]

Example 2 A large aluminum substrate having the same dimensions as in Example 1 was prepared instead of glass. A 10 μm Ni-P layer was formed on this large aluminum substrate by electroless plating.
After forming and then mirror-polishing the surface, the surface is R _max 20 using a tape with No. 1000 alumina abrasive grains.
nm, R _av 3 nm unevenness was formed. Attach this large substrate to the carrier, and through the continuous sputtering device,
Chromium was used as an underlayer, CoCrPt was used as a magnetic film, and a carbon protective layer was formed to obtain a magnetic recording medium base material having a magnetic recording medium formed on the entire surface of a large substrate. This large-sized magnetic recording medium base material was made into a 3.5-inch medium having an outer diameter of 95 mm and an inner diameter of 25 mm and an outer diameter of 6 using an ultrasonic processing machine manufactured by Nippon Thermonics Co.
A 2.5 inch medium having a diameter of 5 mm and an inner diameter of 20 mm was cut out.

A 2-inch magnetic recording medium having an outer diameter of 48 mm and an inner diameter of 12 mm was cut out by using an electric discharge machine manufactured by Japax. The production amount, yield and coercive force are shown in Table 1 as in the examples. The coercive force was good at 1080 to 1100 Oe.

[0026]

Third Embodiment Similar to the first embodiment, a large magnetic recording medium base material having a magnetic recording medium formed on the entire surface of a large substrate is formed. This large-sized magnetic recording medium base material is held in a fixing device shown in the figure, and a glass processing machine using a diamond cutter (Rizaware Co., Ltd., glass processing system, Proca F950) is used to have an outer diameter of 95 mm and an inner diameter. 25mm 3.
A 5-inch medium, a 2.5-inch medium having an outer diameter of 65 mm and an inner diameter of 25 mm, and a 2-inch magnetic recording medium having an outer diameter of 48 mm and an inner diameter of 12 mm were cut out. The cutting speed was 30, 20 and 13 seconds, respectively. Table 1 shows the production amount, yield and coercive force at this time.
The coercive force was good at 1080 to 1100 Oe.

[0027]

[Comparative Example 1] 16 glass substrates each having a desired size and shape, each having a diameter of 3.5 inches (outer diameter 95 mm × 25 mm), 2.
Twenty-five inch glass substrates (outer diameter 65 mm × 20 mm) and two two inch (outer diameter 48 mm × 12 mm) glass substrates were prepared. The glass substrate 15 is attached to the substrate mounting portion 13 of the new support 12.
It was attached to the robot by the robot 14. At this time, some of them fell from the support due to poor mounting. Also, some were found to fall during the sputtering process. The production amount, yield and coercive force are shown in Table 1 as in the examples. The coercive force was as good as that of the example, but the production amount and yield were lower than those of the examples.

[0028]

[Comparative Example 2] Magnetic recording media of various sizes and shapes were prepared in the same manner as in Comparative Example 1 except that a support table that was recycled 80 times was used instead of a new support table. The production amount, yield and coercive force thereof are shown in Table 1 as in Example 1. Not only the production amount and yield but also the coercive force decreased as compared with the examples, and the value was 900 to 920 Oe.

[0029]

According to the present invention, a magnetic layer and a protective layer are formed on a large-sized substrate to prepare a large-sized recording medium base material, which is then cut to a desired size and shape to produce a recording medium. By doing so, it is possible to efficiently manufacture high-quality recording media having different sizes, and it is possible to provide an industrial manufacturing method of recording media having higher production efficiency as the size and shape are smaller.

[Brief description of drawings]

FIG. 1 shows a cutting device for cutting a recording medium from a large-sized recording medium base material showing an example of the manufacturing method of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a recording medium base material before cutting recording media of various sizes and shapes.

FIG. 3 shows a state where a large-sized substrate showing an example of the manufacturing method of the present invention is installed on a carrier.

FIG. 4 is a diagram showing a conventional method of mounting a substrate on a support base.

[Explanation of symbols]

1 Magnetic recording medium base material on which a recording layer and a protective layer are formed on a large substrate 2 Fixing device for magnetic recording medium base material 3 Laser beam 4 Laser processing machine 5 Magnetic recording medium 6 Substrate 7 Underlayer 8 Magnetic layer 9 Protective layer 10 Transfer stand 11 Large board 12 Support stand 13 Board mount 14 Robot 15 Board

[Table 1]

Claims (3)

[Claims] 1. A large-sized substrate having an area capable of holding a plurality of recording media is used, the surface of the large-sized substrate is subjected to finishing treatment, at least a recording layer and a protective layer are formed, and then cut into a desired size and shape to obtain a plurality of substrates. A method of manufacturing a recording medium, which comprises forming individual recording media. 2. The manufacturing method according to claim 1, wherein the method of cutting into a desired size and shape is a method by laser, ultrasonic wave, electric discharge machining or mechanical cutting. 3. The manufacturing method according to claim 2, wherein the large substrate is glass.