JPH01189044A - Production of information recording medium of golden color - Google Patents

Abstract

PURPOSE:To produce an information recording medium of a golden color which has a uniform color tone and luster and has a high reflectivity of laser light by using copper as one target and Al and/or Zn as the other target. CONSTITUTION:The air existing in a vacuum vessel 2 is removed by using an evacuation device 3 and an inert gas such as gaseous argon is supplied from an inert gas supplying device 4 to the vessel 2 and the pressure in the vessel 2 is reduced. The pressure in the vessel 2 is reduced in an inert atmosphere and vapor deposition is executed by using the copper for the one target and the Al and/or Zn for the other target and using the targets T1, T2 as a cathode and an outside plate 1 of the device as an anode. While the particles sputtered and released from the targets T1, T2 are scattered by collision against the inert gas, the particles arrive satisfactorily at a disk substrate 10 disposed alongside the space between the targets T1 and T2. The metals of the targets T1, T2 are deposited by evaporation on the rotating substrate 10 by an opposed target type sputtering method while the disk 10 is rotated within a 10-90rpm range.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an information recording medium exhibiting a golden color.

■Target 1: The most common problem these days, optical discs, compact discs, and CD-ROMs.
are widely used as information recording media. Such information recording media consist of a disk-shaped substrate and a metal thin film provided on the substrate in which countless minute pits or bubbles are formed, and the state of these pits or bubbles is changed to generate a laser beam. There are types that record information by changing the reflectance (or transmittance) of light, etc.

Therefore, in order to record information with high precision, it is necessary that the metal thin film be uniform so that the reflectance (or transmittance) of the laser beam is constant.

Metal thin films in such information recording media can be formed using coating methods, but recently, metal thin films can also be formed using vapor deposition methods, ion blasting methods, sputtering methods, etc. It's becoming more common.

In the above method, aluminum, which has a low melting point and good vapor deposition properties, is most widely used as the vapor deposition metal. Therefore, information recording media generally have a silver color due to the aluminum thin film.

By the way, as an information recording medium, in addition to the above-mentioned silver-colored information recording medium having an aluminum thin film, information recording media exhibiting a golden color are already known. Such a golden information recording medium can be manufactured by depositing gold instead of aluminum.

In this way, information recording media with thin films formed using gold can give a very expensive feel, and the thin films have higher durability and laser light reflectance than aluminum thin films, and have characteristics such as is excellent. However, although thin films formed using gold have the excellent properties mentioned above, their applications are currently very limited because gold is extremely expensive. be.

On the other hand, in addition to all of the above-mentioned metals, alloys of copper and aluminum and alloys of copper and zinc are also known as metals that exhibit a golden color. If thin films can be formed using these alloys by vapor deposition, ion blating, or sputtering, it will be possible to give information recording media an expensive feel and also have good reflectivity for laser beams. Information recording media can be manufactured.

However, when metal thin films are formed by vapor deposition or ion blating using these metals as metal sources or targets, differences in the composition of the alloy used and the thin film deposited may occur due to differences in the boiling points or activities of the metals that make up the alloy. A problem arises in that the metal compositions of the two materials do not match. Therefore, it has been found that it is not possible to produce an information recording medium exhibiting a clear golden color using these methods.

In this respect, when the sputtering method is adopted, the composition of the alloy used as the target and the composition of the obtained alloy thin film are almost the same, so it is possible to use an alloy of copper and aluminum or an alloy of copper and zinc as the target metal. A golden information recording medium can be manufactured.

However, with this method, it is not possible to use up all the alloy used in the target, and the unused alloy cannot be reused. Since alloy targets of copper and zinc or alloy targets of copper and zinc are not cheap, there is a problem in that the resulting information recording medium becomes expensive due to the alloy targets being discarded without being used.

On the other hand, facing target sputtering has recently come into use as a metal vapor deposition method.

The facing target sputtering method is, for example, IEEE
Transaction on Hagnetics Vol.1. As shown in HAG-16°No. 5.198o or Japanese Patent Application Laid-Open No. 57-158380, two flat targets of the same size are placed facing each other, and these two flat targets are used as cathodes. In this method, target metal is deposited by applying a plasma focusing magnetic field to the surfaces of two flat targets using a shield ring as an anode. Japanese Patent Application Laid-Open No. 60-89569 discloses a method of forming a metal thin film in which a concentration gradient is formed in the thickness direction using different metals as two flat targets.

In other words, in this method, sputtering is performed while the substrate is moved from one target to the other, thereby forming a deposition concentration gradient of the target metal in the thickness direction of the substrate in accordance with the distance between the target and the substrate. This is the way to do it.

Therefore, even if copper and aluminum or copper and zinc are used as targets and this method is used as is to form a metal thin film for an information recording medium, copper and aluminum or copper A vapor-deposited metal film is formed in which a concentration gradient of zinc and zinc is formed, and it is impossible to manufacture an information recording medium in which these metals are uniformly distributed and exhibit a golden color.

SUMMARY OF THE INVENTION The present invention aims to solve the problems associated with the prior art as described above, and aims to provide a new method that can produce a golden information recording medium.

More specifically, it is an object of the present invention to provide a novel method for manufacturing a gold-colored information recording medium using a facing target sputtering method.

1 匪ゑゔ1 The method for manufacturing a gold-colored information recording medium of the present invention includes forming a metal thin film on a disk-shaped substrate, using copper as one target, and using copper as the other target. It is characterized by depositing a golden alloy thin film made of the metal used as the target onto the disk-shaped substrate while rotating the disk-shaped substrate by a facing target sputtering method using aluminum and/or zinc as the target. .

According to the present invention, a gold-colored information recording medium can be manufactured by employing a facing target sputtering method and using copper as one target and aluminum and/or zinc as the other target. Furthermore, by depositing the above alloy while rotating the substrate, the metal alloy used as the target can be uniformly deposited over the entire substrate.

The method for manufacturing the golden information recording medium according to the present invention will be specifically described below.

The method for manufacturing the golden information recording medium of the present invention employs a facing target sputtering method using a specific metal as a target that exhibits a golden color when made into an alloy, and vapor-depositing the target metal while rotating a disc-shaped substrate. is the main feature.

FIG. 1 conceptually shows an example of a facing target type sputtering apparatus that can be used for manufacturing the golden information recording medium of the present invention.

The facing target sputtering apparatus that can be used in the present invention basically includes an outer panel 1 of the apparatus, a vacuum chamber 2 whose airtight state is maintained by the outer panel 1, and a gas in the vacuum chamber 2. It has an exhaust means 3 for evacuation, and an inert gas introduction means 4 for supplying inert gas into the vacuum chamber 2.

Inside the vacuum chamber 2, a target holder 5a is fixed to the outer panel 1 of the apparatus via an insulating member.

5b is provided. This target holder 5
8.5 b are placed apart from each other by a certain distance, and are placed so that the targets face each other. Permanent magnets 6a, 61) are provided in the target holders 5a, 5b, respectively, so that their north and south poles oppose each other. Therefore, the target holder 5a is fixed by the permanent magnets 6a, 6b.

A magnetic field is formed between the two in the opposing direction.

The facing target type sputtering apparatus used in the method of the present invention has a target holder 5 in a vacuum Pa2.
On the sides of the permanent magnets 6a and 6b are the permanent magnets 6a and 6b.
A substrate mounting table 7 on which a disk-shaped substrate is mounted is provided parallel to the magnetic field formed between the target holders 5a and 5b. This substrate mounting table 7 is pivotally attached to a rotating shaft 8, and this rotating shaft 8 is rotated by a rotating means 9.

In the method for manufacturing a gold information recording medium of the present invention, vapor deposition is performed while rotating a disc-shaped substrate using, for example, a facing target type sputtering apparatus such as the one described above.

Disc-shaped substrates that can be used in the present invention include plastics such as polycarbonate resin, acrylic resin, olefin resin, parabanic acid resin and epoxy resin, metals such as aluminum, and non-fiber materials such as silicon wafers and glass. used.

The above substrate can be used as is, but a sensitizing layer such as a resin layer or a reflective layer may be further provided on the surface of the disk-shaped substrate.

Further, this disk-shaped substrate may have fine irregularities formed on its surface using a stamper or the like.

In the present invention, the thickness of the substrate can be appropriately set depending on the intended use, but usually a substrate having a thickness of 0.5 to 2.5 B is used.

Such a disk-shaped substrate 10 is mounted on the substrate mounting table 7, and metal is deposited on the surface of the substrate 10.

In the present invention, copper is used as one target T1,
Aluminum or zinc is used as the other target T2. Target T2 may be an alloy of aluminum and zinc.

Note that these metals preferably have high purity, but other metals may be blended or mixed within a range that does not impair the properties of the obtained metal thin film.

The facing target sputtering method in the present invention uses a vacuum chamber 2.
The air inside the vacuum chamber 2 is removed using the exhaust means 3, and an inert gas such as argon gas is supplied into the vacuum chamber 2 from the inert gas supply means 4. The inside of the vacuum chamber 2 is usually lx10-2 to lx1. Reduce the pressure to within O'torr.

Furthermore, it is preferable to reduce the pressure to within the range of lXl0' to 1 x 10-4 torr.

In this manner, the pressure inside the vacuum chamber 2 is reduced under an inert atmosphere, and vapor deposition is performed using the targets T1 and T2 as cathodes and the apparatus outer plate 1 as an anode.

By introducing the inert gas and reducing the pressure to the above range, the particles sputtered from the targets T1 and T2 collide with the inert gas and are scattered. The light reaches the disk-shaped substrate 10 placed on the side of the interspace well.

In the present invention, during the above-described vapor deposition, it is necessary to perform the vapor deposition while rotating the disc-shaped substrate 10. That is, when the facing target sputtering method is used, the metals of the targets T and T2 are vapor-deposited onto the disk-shaped substrate 10 on the side according to the additive. Therefore, if vapor deposition is performed with the substrate fixed, the target T1 side of the disk-shaped substrate 10 (A side in the drawing)
In this case, the content of metal used in target T1 becomes higher,
On the other hand, on the target T2 side (B side in the drawing), since the content of the metal used in target T2 is higher, it is necessary to form an alloy thin film that uniformly contains the metals of targets T and T2 on the disc-shaped substrate 10. It turned out that it was not possible.

Therefore, in the present invention, while rotating the disc-shaped substrate 10, the metal of the targets T1 and T2 is transferred to the rotating disc-shaped substrate 10 by the facing target sputtering method.
By vapor-depositing it on top, it is possible to form an alloy thin film having a uniform composition in both the plane direction and the thickness direction.

In this case, the rotational speed of the disc-shaped substrate 10 is the target T
and T2, the voltage applied to T2, the reduced pressure state in the vacuum chamber 2, the distance between the disk-shaped substrate 10 and the targets T1 and T2, etc. can be set as appropriate, but 10 to 9
0 rl) It is preferable to rotate at a rotation speed within the range of 11, and it is particularly preferable to rotate at a rotation speed within the range of 20 to 50 rpm.
If it is slower than rpn, a non-uniform alloy thin film may be formed in the plane direction and thickness direction,
Even faster rotation hardly improves the uniformity of the resulting alloy thin film.

The thickness of the alloy thin film deposited on the disk-shaped substrate 10 by the above-mentioned facing target sputtering method is usually 50 mm.
~3000V.

The method for manufacturing the information recording medium of the present invention is to form a thin film made of a specific alloy on a disk-shaped substrate by the facing target sputtering method as described above, and then reflect the light onto the alloy thin film according to a conventional method. A layer and a sensitizing layer such as a light absorption layer or a protective layer can be provided. Further, in the information recording medium according to the method of the present invention, after providing a recording layer containing a golden alloy thin film etc. on a disc-shaped substrate as described above, an alloy thin film is formed by using a spacer as necessary through an air layer. The structure can be a known structure such as a sandwich structure in which two disc-shaped substrates are arranged so as to face each other.

]! According to the present invention, a gold-colored information recording medium can be manufactured by adopting a facing target sputtering method and using copper as one target and aluminum and/or zinc as the other target. . Moreover, by depositing the above-mentioned metal while rotating the disc-shaped substrate to form an alloy on the substrate, the metal alloy used as the target can be uniformly deposited over the entire substrate.

Therefore, the obtained information recording medium exhibits a golden color and is uniform in color tone and shine, and this alloy thin film is
Very high reflectance of laser light.

In particular, by adjusting the alloy composition etc., it is possible to form a thin film having a reflectance equal to or higher than that of a gold thin film.

Furthermore, the information recording medium according to the method of the present invention is a golden information recording medium with a uniform color tone, giving a visually very expensive feeling.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

A gold-colored information recording medium was manufactured using a facing target type sputtering apparatus such as Etatsu Yuji.

The target size is 16cm tall and 10cm wide, respectively.
A facing target type sputtering apparatus having a thickness of 1 clI was equipped with aluminum as one target and copper as the other target.

The spacing between the targets was 14 (1 m), and a magnetic field of 1200 e was formed at the center of the targets.

12 polycarbonate disk-shaped substrates with a diameter of 12 were mounted on a substrate mounting table, and the board mounting table was rotated at 2Q rpn. Note that the distance from the center of the target to the center of the disc-shaped substrate was 12.5 cm.

Next, the above-mentioned facing target type sputtering apparatus was installed at a vacuum level of 6
After evacuating to X 10'7 torr, argon gas was introduced to reduce the vacuum inside the device to 8 X 10' torr.
r, and while rotating the substrate at a speed of 2 OrH, a power of 3.0 Kw was applied with the target as the cathode and the shield ring of the substrate as the anode. The target voltage was set to 550 V, the target current was set to 3.5 A, and sputtering was performed for 30 seconds.

By the above operation, a golden alloy thin film of copper-aluminum alloy with a thickness of 500V was formed on the surface of the disc-shaped substrate.

When the thin film thus obtained was irradiated with a laser beam having a wavelength of 780 μm and its reflectance was measured, the reflectance was 61%.

Dog j Self-vomit l A golden alloy thin film was formed in the same manner as in Example 1 except that zinc was used as the target instead of aluminum.

The reflectance of this thin film for laser light with a wavelength of 780 μm is 48
%Met.

Blood Calibration Example 1 A silver aluminum thin film was formed in the same manner as in Example 1, except that aluminum was used as both targets.

The reflectance of this thin film for laser light with a wavelength of 780 μm is 48
%Met.

A golden thin film was formed in the same manner as in Example 1, except that gold was used as both targets.

The reflectance of this thin film for laser light with a wavelength of 780 μm is 60
%Met.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing an example of a facing target sputtering apparatus that can be used for manufacturing the golden information recording medium of the present invention. DESCRIPTION OF SYMBOLS 1... Apparatus outer plate, 2... Vacuum chamber, 3... Exhaust means, 4... Inert gas introduction means, 5 a, 5 b...
・Target halter, 6 a, 6 b...Permanent magnet, 7... Board mounting stand, 8... Rotating shaft, 9...
Rotating means, 1o...disk-shaped substrate, TI, T2...target

Claims (2)

[Claims] (1) A method for manufacturing an information recording medium, which involves forming a metal thin film on a disk-shaped substrate, using opposed target sputtering using copper as one target and aluminum and/or zinc as the other target. 1. A method for producing a golden information recording medium, which comprises depositing a golden alloy thin film made of a metal used as a target on the disk-shaped substrate while rotating the substrate. (2) The method for manufacturing a golden information recording medium according to claim 1, wherein the rotational speed of the disk-like substrate is within a range of 10 to 90 rpm.