JPH04288287A - Preparation of optical recording carrier - Google Patents

Abstract

PURPOSE:To extend the environment-resistant life of an optical disk by improving the close adhesivenss of a substrate and a recording film. CONSTITUTION:After the surface 2 of a substrate 1 is modified by ion bombardment, an optical recording film 4 of a Te or TeOx type to which Pd is added in an amount of 2at%-below 5at% is formed. The gas pressure in a vacuum tank at the time of ion bombardment is held to 1X10<-2> Torr or more by the introduction of oxygen and ion bombardment is performed for 5min or more. Further, a Te-Pd metal crystal film 3 with thickness of 50-300Angstrom is provided between the optical recording layer and the substrate to improve the close adhesivenss of the optical recording layer and the substrate and an optical disk generating no sensitizing phenomenon immediately after recording and having a large C/N value can be realized.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an optical record carrier that can be used in an optical disk memory that records and reproduces information signals by irradiating a high-speed rotating disk formed with a Te-based optical recording film with pulses of laser light. Regarding the manufacturing method.

0002

[Prior Art] A phase-change optical disk memory using a tellurium (Te)-based optical recording material changes the irradiated area from an amorphous phase to a crystalline phase due to the heat generated during irradiation with a light pulse such as a laser beam. The recording film is used to record signals, and the recorded signals are reproduced by changes in the amount of light reflected by the recording film due to changes in the crystal phase.

[0003] Here, it may take a relatively short time for the tellurium oxide (TeOx, where x has an upper limit of 2) film in an amorphous state to reach a crystalline state.

The phenomenon in which the amplitude and C/N value of the reproduced signal after recording increase with time while reaching the crystalline state is called a sensitization phenomenon.

In order to reproduce a recorded signal with a high C/N value immediately after recording, it is necessary to eliminate the above-mentioned sensitization phenomenon and to obtain a high C/N value immediately after recording. In order to improve this sensitization phenomenon, methods of adding different types of materials to TeOx have been proposed. In this method, it is believed that different materials play the role of crystal nuclei in the TeOx film, promote phase change of TeOx, and improve the sensitization phenomenon.

However, it has been found that when the relative amount of Te in the recording film decreases by adding different types of materials, the C/N value decreases.
As shown in the specification of No. 291, palladium (Pd) is added from 2 at% to less than 5 at% to the Te-based optical recording film 4, and as shown in FIG. 3, the disk substrate 1 and the Pd-doped TeOx A two-layer film optical record carrier in which a Te--Pd metal film 3 is provided between a film 4 has been proposed.

[0007]

[Problem to be solved by the invention] Such conventional Te
When recording and reproducing signals using an Ox-Pd recording film, when the optical record carrier is rotated at 1,800 rpm, 33 ms, which is the time required for one rotation, has elapsed after recording, and 30 seconds and 60 seconds after recording have elapsed. No difference was observed in the C/N value after seconds had elapsed, and it was confirmed that there was no sensitization phenomenon. Also,
Single frequency is 57d when recording a 5MHz signal
The C/N value of B was obtained.

However, in such a conventional recording film, the interface between the disk substrate 1 and the TeOx-Pd recording film 4 is Te-
Since it is composed of Pd metal film 3, TeOx-Pd
Compared to this, there is a problem in that the Te--Pd metal film 3, which has weak adhesion to the disk substrate made of polycarbonate, for example, may cause minute peeling in a high-temperature, high-humidity atmosphere.

For example, in order to find out the disk life of a conventional disk in a high temperature and high humidity atmosphere, an accelerated test was carried out.
32℃ by Arrhenius plot of test results.
An estimated lifespan of more than 10 years was obtained when converted to -80% RH. Although the value of estimated lifespan of 10 years poses no practical problem, P
Te-P consisting only of a recording film of TeOx doped with d
When a similar accelerated test was conducted using a disk without a metal film, an estimated lifespan of 20 years was obtained, which is twice as long as the conventional example. Therefore, in order to improve the reliability of the disk, it is possible to further improve the estimated lifetime of the disk by improving the state of the interface between the substrate and the TeOx-Pd recording film.

The present invention is intended to solve these problems with conventional disks, and aims to further extend the life of the disk by improving the adhesion between the substrate and the recording film.

[0011]

[Means for Solving the Problems] In order to solve this problem, the present invention provides an ion bombardment method that uses ion bombardment before forming a Te or TeOx optical recording film doped with Pd of 2 at.% or more and less than 5 at.% on a substrate. This pre-processes the substrate.

[0012] Furthermore, oxygen is introduced before ion bombardment to the substrate, and the gas pressure in the vacuum chamber at the time of ion bombardment is 1×10-2T.
orr or higher, and ion bombardment is performed for less than 5 minutes.

Further, a Te--Pd metal crystal film with a thickness of 50 to 300 Å is provided between the Pd-doped optical recording film layer and the substrate.

[0014]

[Operation] In the optical record carrier of the present invention, a Te-Pd metal crystal film with a thickness of 50 to 300 Å is formed after the substrate is pretreated by ion bombardment with O2 gas to prevent oxidation of the Te-Pd film. However, a TeOx-Pd recording layer is provided on top of this.

[0015] Before forming the recording film of the present invention,
Oxygen is introduced and the gas pressure inside the vacuum chamber is 1 x 10-2 Torr.
Since ion bombardment is applied to the substrate for more than 5 minutes, the adhesion between the Te-Pd film and the substrate is improved by cleaning and roughening the substrate surface, eliminating the possibility of film peeling under high temperature and high humidity conditions, and improving the weather resistance of the disk. will improve. According to the test results, Pd
Estimated lifespan equivalent to that of a disk consisting only of a TeOx recording film doped with (20 years at 32°C - 80% RH)
was gotten.

Furthermore, depending on the molding conditions of conventional disk substrates, burr-shaped resin may remain on the edges of recording grooves, and when a film is formed on such a substrate, recording may occur along the burr-shaped resin. Destruction of the membrane may occur, and this destruction results in a decrease in the C/N value. However, according to the present invention, such burr-like resin can be removed in advance by ion bombardment, so that it is possible to solve the problem of a decrease in C/N due to destruction of the recording film.

Furthermore, since the TeOx-Pd metal film 3 is formed between the TeOx-Pd recording film 4 and the substrate 1, the TeOx-Pd recording film 4 is
Since Te crystal grains with more advanced crystallinity than in the Ox--Pd recording film 4 are produced, a high C/N value can be obtained. Therefore, according to the present invention, it is possible to realize a high C/N and highly reliable disk without post-recording sensitization phenomenon.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the structure of an optical record carrier manufactured by a manufacturing method according to an embodiment of the present invention. As shown in the figure, after forming a layer 2 subjected to ion bombardment on the surface layer of a disk substrate 1, a Te-Pd metal crystal film 3 with a thickness of 50 to 300 Å and a T
An eOx-Pd recording film 4 is formed.

The optical record carrier of the present invention can be formed using a sputter evaporation method, for example, as shown in FIG. As shown in the figure, a disk holder 1 inside a vacuum chamber 10
The disk substrate 1 is held at 1, and the inside of the vacuum chamber is set at 10-
Evacuate to 6 Torr. After vacuum evacuation, vacuum chamber 1
02 gas is introduced into the vacuum chamber 10 at a rate of, for example, 10 SCCM, and the gas pressure within the vacuum chamber 10 is adjusted to 1×10 −2 Torr. High voltage power supply 1 with switch 12 turned on to contact A13 side.
4 to the disk holder 1 through high voltage, e.g. 500V.
1, a glow discharge occurs in the vacuum chamber 10 and O2
The ions violently collide with the disk substrate 1, and the surface layer of the disk substrate is cleaned and roughened by the ion bombardment. Here, the lower limit of the gas pressure in the vacuum chamber 10 during ion bombardment must be 1.times.10@-2 Torr, and the lower limit of ion bombardment time must be 5 minutes. It was confirmed by electron microscopy observation of the substrate surface that the substrate surface layer was not cleaned or roughened if these conditions were not met.

After the ion bombardment is completed, switch 12 is closed to contact B.
15 side, stop the introduction of O2 gas and replace it with Ar gas, for example, after introducing 50SCCM, the inside of the vacuum chamber 10 is
The pressure is adjusted to x10-3 Torr. In this state, when a high voltage, for example 500 V, is applied to the target 16 containing Te and Pd through the high voltage power supply 14, a glow discharge occurs in the vacuum chamber 10, and the material Te-Pd of the target 16 is sputtered and evaporated from the surface of the target 16. , disk substrate 1
A Te--Pd metal film 3 is then formed thereon. In this example, the Te-Pd metal film 3 with a thickness of 100 Å could be formed in about 20 seconds.

Here, the thickness of the Te--Pd metal film 3 is 50 Å.
If it is less than 300 Å, a film with an island-like structure will be formed and will not be distributed uniformly on the substrate, so it will not be effective. If it exceeds 300 Å, peeling will easily occur at the boundary of the film due to film stress during the formation of the two-layer film. As a result, water or the like enters the peeled portion, oxidizes the film, and prevents normal recording and reproduction. Therefore, the thickness of the Te-Pd metal crystal film 3 is preferably within the range of 50 to 300 Å.

After the formation of the Te--Pd metal crystal film 3 is completed, O2 gas is introduced again at a rate of, for example, 10 SCCM, and a high voltage, for example, 500 V, is applied to the target 16 containing Te and Pd through the high-voltage power supply 14. By this operation, a TeOx-Pd recording film 4 is formed on the Te-Pd metal film 3 of the disk substrate 1. Approximately 5 minutes of film formation time is approximately 1,000
It was possible to form a TeOx-Pd film with a thickness of .

Here, the Te--Pd metal crystal film 3, TeOx
- If the Pd content of the Pd recording film 4 is 2 atomic percent (at%) or less, a sensitization phenomenon is confirmed.
%, the C/N value increases by about 1 dB between 33 ms and 60 seconds after recording. Furthermore, if the Pd content is 5 at% or more, the C/N value will decrease. Therefore, Pd
The content of is desirably 2 at% or more and less than 5 at%.

[0024] Target 16 used in this implementation
A material containing Te and Pd may be used, or a similar effect can be obtained by using a Te target and a Pd target and sputtering and evaporating these two types of targets at the same time.

[0025] The optical record carrier prepared according to the present example described above is rotated at, for example, 1,800 rpm to generate a single frequency,
For example, the C/N value was measured 33 milliseconds and 60 seconds after recording a 5 MHz signal. In both cases, a good C/N value of 57 dB was obtained. Also, 3
At 2°C and 80% RH, an estimated lifespan of 20 years was obtained, which is twice the conventional value.

[0026]

Effects of the Invention As is clear from the description of the embodiments above, the optical record carrier of the present invention has a Te--Pd film with a thickness of 50 to 300 Å after pretreatment of the substrate by ion bombardment with O2 gas. A metal crystal film is formed, and TeOx-
A Pd recording layer is provided. By this treatment, the substrate surface is cleaned and roughened by ion bombardment, so that the Te--Pd metal film is difficult to peel off from the substrate under high temperature and high humidity, and a good C/N value can be obtained. Furthermore, an effect can be obtained in that the estimated life of the disk can be twice as long as the conventional one.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of an optical disc according to an embodiment of the present invention.

[Figure 2] Configuration diagram showing the same manufacturing process

[Figure 3] Cross-sectional view of a conventional optical record carrier

[Explanation of symbols]

1 Disk board 2 Layer subjected to ion bombardment 3 Te-Pd metal film 4 TeOx-Pd recording film 10 Vacuum chamber 11 Disc holder 12 Switch 13 Contact A 14 High voltage power supply 15 Contact B 16 Target

Claims (3)

[Claims] [Claim 1] The main component is tellurium (Te) or tellurium oxide (TeOx, where x has an upper limit of 2) on the substrate,
A method for producing an optical recording carrier, in which the substrate is pretreated by ion bombardment before forming an optical recording film doped with 2 at.% or more and less than 5 at.% of Pd. 2. Oxygen is introduced before ion bombardment, and the gas pressure in the vacuum chamber at the time of ion bombardment is 1 x 10-2 Torr or more,
2. The method for producing an optical record carrier according to claim 1, wherein the ion bombardment time is 5 minutes or more. 3. Between the optical recording film and the substrate, 50 to 3
2. The method of manufacturing an optical record carrier according to claim 1, wherein a tellurium-palladium (Te-Pd) metal crystal film having a thickness of 00 Å is provided.