JPS62266746A - Optical recording medium and its production - Google Patents

Abstract

PURPOSE:To stabilize the boundary of a recording layer and to prevent the deterioration by the oxidation reaction of the boundary of the substrate side recording layer by providing a protective layer contg. an easily oxidizing metal on the substrate side surface of the recording layer. CONSTITUTION:The protective layer 3 consisting of the easily oxidizing metal is provided on the substrate 1 side surface of the recording layer 4 which is provided on the substrate 1 consisting of a transparent synthetic resin and consists of a thin metallic film rewritable by light. The layer 4 is formed on the layer 3 without exposing the layer 3 to the atm. after formation of said layer in the stage of production. The boundary of the layer 4 is thereby stabilized and the deterioration by the oxidation reaction on the layer 4 boundary on the substrate 1 side is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application] The present invention relates to an optical recording medium on which information is recorded, reproduced, erased, etc. using light such as a laser. More specifically, optical recording involves forming a recording layer made of a metal film whose reflectance changes due to phase transition between crystal and amorphous on a transparent synthetic resin substrate, and reproducing information by changing the reflectance. Or gold Iil with easy magnetization direction perpendicular to the film surface on a transparent synthetic resin substrate.
The present invention relates to an optical recording medium with excellent environmental resistance, which is used for magneto-optical recording in which a recording layer made of a thin film is formed and information is reproduced by the magneto-optic effect.

[Prior Art] Optical recording media are being intensively researched and developed as high-density, large-capacity information storage. In particular, various materials and systems have been announced in a wide range of application fields for optical recording media that allow additional information to be recorded and erased, and their practical application is eagerly awaited.

As the above-mentioned additional recording and erasable optical recording material, for example, F8Tb described in Japanese Patent Application Laid-Open No. 52-31703,
Fe Tb Gd described in JP-A-56-126907@
.

FeTb described in Tott Publication No. 58-73746
Co, FeCo Dy, International Application Publication W 086
There is a phase change type FeTe described in Japanese Patent Application No. 1835/1835. However, most of the storage materials that make up the recording layer of optical recording media that allow for additional recording and erasing of information are susceptible to corrosion such as oxidation, so it is necessary to improve their oxidation resistance for practical use. It is said.

On the other hand, for example, JP-A-59-110052 discloses a method of preventing oxidation of the recording layer of an optical memory element by sandwiching the recording layer between two oxygen-free layers, at least one of which is a dielectric layer. It is proposed that. In this case, it is necessary that the dielectric layer does not contain 'R elements, and the dielectric layer should include AflN, MQ
F2, Zns, CeF3, AlF2・3Na
It is said that it is preferable to use a nitride such as F, Si 3 Ns, or a fluoride. However, in this configuration, deterioration of the recording interface due to oxygen adsorbed to the recording layer interface,
Furthermore, there is a concern that the dielectric layer and the recording layer may be degraded by oxygen passing through the transparent synthetic resin substrate, and further improvement in oxidation resistance is desired.

In addition, in this configuration, SiO, S, which are widely used as the transparent dielectric film like the above-mentioned nitrides and fluorides, are used.
i 02, T! There is a restriction that oxides such as Oz and Zr z 03 cannot be used as transparent dielectric films for optical recording media.

[Objective of the Invention 1] The present invention was conceived in view of the current situation, and its object is to provide an optical recording medium having a recording layer on a transparent synthetic resin substrate and free from the above-mentioned problems. Specifically, the first objective is to stabilize the recording layer interface and prevent deterioration due to oxidation reaction at the recording layer interface on the substrate side.

A second purpose is to prevent deterioration at the interface due to oxygen in the air entering the recording layer from the substrate side when the optical recording medium is left in the air.

Furthermore, a third object is to reduce adsorption of oxygen to the interface of the recording layer of the optical recording medium to prevent deterioration of initial recording characteristics due to oxidation.

The fourth purpose is to stabilize the interface against thermal shock.

[Constitution 0 action of invention] The above objects are achieved by the invention as follows.

That is, the present invention provides an optical recording medium having a recording layer made of a metal thin film that can be changed by light on a substrate made of a transparent synthetic resin, in which at least 5ζ of the recording layer is made of a metal that is easily oxidized or its like on the plate side. A first invention is an optical recording medium characterized by being provided with a thin protective layer containing an alloy,
A second invention provides a method for manufacturing an optical recording medium, characterized in that, in manufacturing the optical recording medium of the first invention, after forming the protective layer, a recording layer is formed thereon without exposing the protective layer to the atmosphere. That is.

In addition, in the present invention, metals that are easily oxidized are those whose free energy change (-ΔG: Gibbs free energy change) of oxide formation is 120) (cat/mol) per metal atom.
Examples of metals having a higher than e, such as Ti and zr.

Y, A1. Cr, MO, etc. From the reactivity with oxygen, the free energy change is more preferably 150 Kcal.
/mole or more, such as Ti, Zr, and Y.

It is A1 etc. In addition, the protective layer provided on the substrate side of the recording layer has low thermal conductivity to prevent heat dissipation in the bit part and obtain good recording characteristics by considering the recording characteristics and shape of the bit during recording with laser light. Metal is preferred. Since l”e metals are often used as the recording layer, the thermal conductivity at room temperature is 0.1Ca1/(cIR-3eC-de
9) It has been found that the following metals are preferred, especially Ti or Z or alloys thereof.

In addition, in a method in which light is incident from the substrate side and information is reproduced by reflected light, the change in the refractive index is preferably small even when oxidized, and the refractive index of the oxide is 1.8.
It is desirable to use Ti or Zr, or an alloy thereof, which is the above. .

Further, the protective layer may be alloyed with other elements as long as the above characteristics are not impaired.

Furthermore, the film thickness of the above-mentioned protective layer is such that light passes through the protective layer from the substrate side and is irradiated onto the recording layer, and the reflected light is retained again.
! ! In the method of reproducing information by passing the protective layer through a transparent synthetic resin substrate, it is preferable to make the protective layer as thin as possible because if the protective layer absorbs a lot of light, the signal strength against the noise inherent in the reproduction system will decrease. For example, taking Ti as an example, the thickness is preferably 50 Å or less so that the light absorption is 20% or less, and more preferably 20 Å or less so that the light absorption is 5% or less. In addition, in terms of oxidation resistance, it is recommended to keep 2! ! Are the layers necessarily continuous? Although it is not necessary to form the S film layer, a film thickness of 5 Å or more is preferable, and it is further preferable to form three continuous source IF layers.

By the way, in the above-mentioned present invention, from the viewpoint of improving durability, it is preferable to form a protective layer also on the surface of the recording layer opposite to the substrate side, and more preferably on the edge portion of the recording layer, in other words, on the side portion as well. Preferably, it is covered with a protective layer. In these configurations, the protective layer on the opposite surface and side of the recording layer from the substrate does not necessarily have to be a metal layer like the aforementioned protective layer on the substrate side, but for the reasons mentioned above, the protective layer on the substrate side is ″3
L! A metal layer made of the same easily oxidized metal as i is preferable, and a metal layer containing at least one of Ti and Zr is particularly preferable.

In addition, the optical recording medium of the present invention has the following properties: A structure in which a dielectric layer is provided between the first layer and the substrate is preferable because of the interference effect in the environment-resistant magneto-optical medium.

In the present invention described above, a metal that is easily oxidized in contact with the recording layer interface on the transparent synthetic resin substrate side, preferably a metal that has lower heat transfer than the recording layer, specifically at least Ti, Zr, etc.
Since the structure includes a protective layer made of a metal thin film containing one of the above, oxygen at the recording layer interface on the transparent synthetic resin substrate side reacts with the protective layer at the recording layer interface to form an oxide. , deterioration of the recording layer is prevented. This makes it possible to prevent oxidation reactions at the interface of the recording layer due to oxygen entering from the substrate side, oxygen adsorbed during medium formation, etc., and it is possible to obtain an optical recording medium with excellent corrosion resistance.

In addition, when comparing the case where the recording layer is directly laminated on the transparent synthetic resin substrate or the case where it is further laminated via a dielectric layer, and the case where the recording layer is layered on the protective layer made of the metal thin film of the present invention, The structure of the present invention is particularly advantageous in the case of a phase-change metal recording layer such as FeTe or a magneto-optical metal recording layer such as FeCoTb, since the metal is laminated on the metal layer, so the affinity is greater and the continuous layer at the interface is better. Easy to form.

In addition, in a structure using Ti, Zr, or an alloy of these as the material, the coefficient of thermal expansion is similar to that of the e-based recording layer.
Since it has a thermal expansion coefficient between that of dielectric materials such as nS and Ti02, it has been found to have the effect of relieving strain at the interface during thermal shock and stabilizing the recording medium. did.

Furthermore, in a structure in which a dielectric layer is provided on a transparent synthetic resin substrate, even if adsorbed oxygen exists on the surface of the dielectric layer, a protective layer made of a metal thin film that is easily oxidized is formed on the dielectric layer, so the dielectric layer is When forming the protective layer, adsorbed oxygen on the surface reacts with the metal of the protective layer and is removed. Therefore, when forming the recording layer on the protective layer, it prevents deterioration of recording characteristics due to deterioration of the recording layer interface and provides excellent optical performance. Recording characteristics can be obtained.

In particular, according to the second invention, by forming the recording layer on the protective layer without exposing the protective layer to an oxygen atmosphere such as the atmosphere after forming the protective layer, initial deterioration of the recording layer due to surface absorption of oxygen, etc. can be prevented. The thickness of the protective layer 211 can be reduced, and great effects can be obtained in terms of productivity and optical properties. Note that, from the viewpoint of adsorbing oxygen to the layer interface, it is preferable to form the entire layer without exposing it to the atmosphere.

In addition, in the configuration in which a protective layer is provided on the surface of the recording layer opposite to the substrate, and even on the side surface thereof, when the recording medium is left in the air, oxygen in the air will not enter the recording layer. This is prevented because oxygen reacts with the metal of the protective layer to form an oxide, and an optical recording medium with better corrosion resistance can be obtained. However, since these areas are not directly linked to the deterioration of the recording surface, it may be necessary to protect these areas. ! The layer may be omitted, or a dielectric layer and/or a resin may be used as a protective layer for sealing.

It is clear from the gist of the present invention that the present invention described above is applicable to all optical recording media using transparent synthetic resin substrates.

That is, those in which a recording layer is formed directly on a transparent synthetic resin substrate, those in which a recording layer is formed through a dielectric layer, the metal layer and dielectric layer disclosed in JP-A-59-52443, etc.
The present invention can be applied to optical recording media with various laminated structures, such as those in which recording layers are sequentially formed, and those that are bonded together so that the recording layers face each other and the substrate is on the outside to enable double-sided recording.

As the synthetic resin substrate in the present invention, polycarbonate resins, acrylic resins, epoxy resins, 4-megabentene resins, and copolymers thereof can be used, but they are limited in terms of mechanical strength, weather resistance, heat resistance, and moisture permeability. Polycarbonate resin is preferred.

As the 8th layer, any reusable material that is made of a metal thin film and that can be recorded and reproduced using light can be used. Such a recording layer may be a magnetic metal thin film known as a magneto-optical recording material, which has an easy magnetization direction perpendicular to the film surface and can reproduce information by creating an arbitrary reversal magnetic domain, or a phase transition type optical recording material. Crystal and amorphous by light irradiation known as '! R
There are metal thin films whose reflectance changes due to a reversible phase transition between them.Specifically, magneto-optical recording materials include Fe-Tb alloys (7) Fe-Tb-Co alloys, Fe-Tb-Gd alloys, etc. As the phase change type optical recording material n, Fc-Te
, 5n-Te-8e, Ga-8e-Te, etc. are known. Among these, the present invention can be particularly advantageously applied to a recording layer made of a metal thin film containing iron.

Furthermore, as a dielectric layer, AdanN, MIJF2゜Zn s
, Cc Fe, A1'F3 ・3Na F, S! 3N
a, SiO, StOz, Ti02, 7
Nitride such as r203, fluoride 9M compound, etc. can be used, but Zn, which has a higher refractive index, is preferable from the viewpoint of interference effect.
S or Ti0z is preferable.

The optical recording medium according to the present invention is produced using the r-steaming method in a vacuum chamber.

It is manufactured by a physical thin film formation method such as sputtering method or a synthetic method using a chemical IJ151 formation method, but as mentioned above, the formation of each layer is performed without exposing the surface of each layer to an oxygen atmosphere such as the atmosphere. It is preferable to form layers, and specifically, it is preferable to form each layer continuously in a vacuum chamber while maintaining a vacuum. This method can reduce the presence of oxygen at the interface between each layer, particularly at the interface of the recording layer, and can reduce the oxidation reaction of each layer.

[Example 1] The structure shown in FIG. 1(A), that is, a dielectric layer 2. First protective layer 3. Recording layer 4. A magneto-optical recording medium in which the second protective layer 6 was sequentially laminated was prepared as follows.

As the substrate 1, an acrylic resin substrate of 20 x 20 am and a thickness of 1.2 rMm was heated using an electron beam evaporator (manufactured by Anelva H E).
VD-500A type) fixed in the vacuum chamber of 4X10-71
O: ``Exhaust the air until it drops below.''

In addition, this 'A picture has two evaporation sources so that two-dimensional WA deposition can be performed, and each evaporation source is set with six types of substances, and by sequentially switching, it is possible to continuously MM the substances without breaking the vacuum. The zns, 'rr, and r-eCo alloys were set as one evaporation source and Tb was set as the other evaporation source, and a laminate was formed without breaking the vacuum as follows.

First, to form the dielectric layer 2, ZnS is used as an evaporation source, and the evaporation source is irradiated with an electron beam. After the znS is melted, evaporation is started and at the same time the electron beam is controlled so that the deposition rate is about 5 people/second. After 1 minute, the shutter was opened and approximately 800 ZnS were deposited on the acrylic substrate.
A dielectric layer 2 was formed.

Next, in order to form the first protective layer 3 on the ZnS dielectric layer 2, the evaporation source was changed to Ti, and about 10 Ti layers were deposited at a deposition rate of about 0.5 layers/second using the same method as described above. do,
A first protective layer 3 made of Ti was formed.

Subsequently, in order to form a magneto-optical recording layer made of FeTbCo as the recording layer 4, the evaporation source was changed to Feyowt%.

An alloy of 30 wt % CO and Tb are used, and binary vapor deposition is performed in the same manner as described above. The deposition rate at this time is F(!
The Co alloy was controlled to be 3.5 people/second and the Tb was controlled to be 3.2 people/second. This results in FeTbC'.

Approximately 1000 pieces of the alloy were deposited to form the recording layer 4.

-Finally, to form the second protective layer 5 that protects the exposed surface of the recording layer 4, the evaporation source is changed to Ti again, and the deposition rate is about 1000 by the same method as described above at a deposition rate of about 0.5 people and 77 seconds. This layer was deposited to form the second protective layer 5.

By the above method, a laminate of acrylic resin/Zn S/Ti /Fe Tb Co /Ti having the structure shown in FIG. 1(A) was produced.

In this laminate, the wavelength is 830 nm from the acrylic substrate side.
The reflectance was measured when the light was incident.

The results are shown in Example 1 in Table 1.

Next, this laminate was left at constant temperature and humidity of 55° C. and 60% RH for 1000 hours. Thereafter, the reflectance at a wavelength of 830 nm was measured in the same manner as before standing. The results are shown in Example 1 in Table 1.

[Comparative Example 1] Similar to Example 1, 20×2
Zn S on an acrylic substrate with a thickness of 0 mm and a thickness of 1.2 mm.

Acrylic/Zn S/Fc Tb shown in FIG. 1(B) was deposited with 800, 1,000, and 1,000 layers of Fe"rb Co and Ti at the same deposition rates as in the example, respectively, and without the first protective layer 3. A Co/Ti laminate was produced.

In this laminate, wavelength 83 was measured using the same measurement method as in the example.
The reflectance at Qrv was measured. The binding is shown in Comparative Example 1 in Table 1.

Next, this laminate was left at constant temperature and humidity of 55° C. and 60% RH for 1000 hours. After that, wavelength 83 as before leaving
The reflectance at 0nI11 was measured. The results are shown in Comparative Example 1 in Table 1.

As is clear from Table 1, in Example 1, the reflectance did not change at all, whereas in Comparative Example 1, it was 61%.
It decreased from 54% to 54%.

As described above, the merits of the present invention have been demonstrated.

[Example 2] Diameter 200 am'; thickness 2.5 μ in a 1.2 am disc
Polycarbonate resin (P
The disk substrate of C) was equipped with a 3-target high-frequency magnetic resonance bar, and a vine-mounted (ANELVA ■'IS P F-4)
Fixed in a vacuum chamber of 4 x 10-7
Tor "was exhausted until it reached below. At this time, the substrate 1 was water-cooled and rotated at 15 rpm.

Next, A gas (5N) was introduced into the vacuum chamber, and the pressure was 1X.
Adjust the gas flow 9 to 1O-2 TOrr, target a ZnS disk with a diameter of 100 #l and a thickness of 5M, discharge power of 100W, and discharge frequency of 13.
．． About 800 layers of Zn were deposited as the dielectric film 2 by high frequency sputtering at 56 MHz.

'Subsequently, as the first protective layer 3, the target was changed to T1 and about 10 Ti films were deposited under the same discharge conditions as described above.

Furthermore, as the recording layer 4, the target is Fe1rTb23CO.
-8 alloy (the suffix indicates the composition (atomic %))
Approximately 1,000 l''e 7b Co 4 gold films were deposited under the same conditions as in E.

In addition, when forming each of the above-mentioned films, Zn 81g1. The Ti film and FeTbCo alloy film have a diameter of 200. A mask is placed on the substrate so that the film is deposited within a radius of 90 mm from the center.

Finally, this mask was removed and a film was deposited on the entire surface of the substrate, and a Ti target was used as the second protective layer 5.
Approximately 200 -rts were deposited under the same discharge conditions as described above.

In the above order, the second protection shown in FIG.
A laminate of S/Ti /Fc Tb Co /Ti, that is, a magneto-optical recording medium was obtained.

The C/N of this laminate [in addition, C/N-8/N+101
oo (1 tone band)/<resolution bandwidth)] was measured. This measurement was performed by rotating the disc at 900 rp-1.02
After recording a 4 MHz signal with a 3.5 mW semiconductor laser beam, it was read out with a 0.8 TrLW semiconductor laser beam. The applied magnetic field is IKOe (Oersted). The results are shown in Example 2 in Table 2.

Next, this laminate was left at constant temperature and humidity of 45° C. and 90% RH for 200 hours. The C/N was then measured. The results are shown in Example 2 in Table 2.

[Comparative Example 2] PC/Z shown in FIG. 2(B) in which the first protective layer 3 is not provided by high-frequency magnetron sputtering as in Example 2
A n S/Fe Tb Co /Ti laminate was produced.

The C/N of this W4 layered body was measured. The results are shown in Comparative Example 2 in Table 2.

Next, this laminate was kept at constant temperature and humidity at 45°C and 90% RH for 2 hours.
It was left for 00 hours. The C/N was then measured.

The binding is shown in Comparative Example 2 in Table 2.

As is clear from Table 2, in Example 2, the C/N did not change at all, whereas in Comparative IM2, the C/N decreased from 51 dB to 47 d3.

As mentioned above, the effectiveness of the present invention was demonstrated.

[Example 3] Direct sputtering with a purity of 99.9% was installed in the same high-frequency magnetron sputtering equipment as in Example 2, which enables sputtering of three substances without breaking the vacuum. ¥! A composite target with a 10α FO target, 99.99% 5a11 square, and 1ai + shore Te and a Z target were provided. In addition, a 1.2 g thick, 40 x 40 as + square polycarbonate resin substrate was prepared. PC) was attached to a water-cooled substrate holder approximately 5α away from the target surface.

After evacuating the vacuum chamber to 5 x 10” Torr,
9.999% A'gas 1 x 1O-2T orr
A ZR film layer with a thickness of approximately 20 mm was formed as the first protective layer by sputtering Z' at a power of 100 W. On top of that, a ZR film layer with a thickness of approximately 20 mm was formed by sputtering at a power of 100 W. FejoTeta is sputtered from a target to form a recording layer with a thickness of about 2,000 people.
A layer g (subscript numbers as described above) was formed. Next, sputter the 7r target again to form a 300 layer as a second protective layer, PC/Zr/F8ba Tem/Zr
A laminate was created.

The sample was held in an accelerated deterioration tester (Model PL2E manufactured by Tabai Seisakusho), which maintained this laminate at a constant temperature and humidity of 70° C. and 90% RH. As an indicator of sample deterioration, change in electrical resistance of the alloy after 380 hours of testing compared to before testing (resistance ratio)
The results are shown in Table 3, Example 3.

[Comparative Example 3] Protected in the same manner as in the above example! P without any i-layer
A C/Fe in Tetta laminate was produced.

Accelerated deterioration test 111 in which this laminate was kept at a constant temperature and humidity of 70°C and 90% RH (the sample was held in a PL2E'l made by Takai Seisakusho. 380
Change in the electrical resistance of the alloy after the test between @ compared to before the test (
Resistance ratio) results are shown in Example 3 in Table 3.

Table 3 As is clear from Table 3, the resistance change in Example 3 was smaller than that in Comparative Example 3, demonstrating the effectiveness of the present invention.

[Example 4] In the same high-frequency magnetron sputtering apparatus as in Example 2, which can sputter three substances continuously without breaking the vacuum, a 2×2 cm, 1.1. A glass substrate was provided.

Next, the inside of the vacuum chamber was evacuated to 2 x 1G” Torr, and then Ti was used as a target and the atmosphere was evacuated to Oz/Ar −1ov.
Approximately 500 TiOx layers are deposited as a dielectric layer by sputtering at a pressure of f3 x 10-37 orr using a mixed gas of 01%. After that, O without stopping the discharge.
The z/Ar gas was replaced with the A gas, introduced into the vacuum chamber, and about 1 OA of Ti was deposited as a protective layer, and the discharge was stopped.

Next, the target was changed to a Febf Tb 23 Cos alloy, and Fetf Tbu
Approximately 1000 Co 9 alloy films were deposited, and glass/TiO
A 2/Ti/Fc Tb Co laminate was obtained.

Next, as Comparative Example 4, a glass/Tt 02 /FOTbCo without a Ti layer of ff1ll was prepared in the same manner as described above.
A WA layered body was obtained.

When the laminate of Example 4 and the laminate of Comparative Example 4 were subjected to Auger electron spectroscopy (ANELVA IJAES), it was found that Comparative Example 4
It can be seen that the content of culm M elements that proceed from the surface to the glass substrate increases, and that a large amount of oxygen is mixed into the Fc Tb Co film. In contrast, in Example 4 Fe
It was observed that oxygen in the Tb Co film was significantly reduced compared to Comparative Example 4.

1] The above results demonstrated the effectiveness of the present invention.

[Brief explanation of the drawing]

Figures 1 (A) and (B) are cross-sectional views of the laminate in Example 1 and Comparative Example 1. Figures 2 (A) and (B) are v in Example 2 and Comparative Example 2.
It is a sectional view of a 4g body. 1: Substrate 2: Dielectric layer 3: First protective layer 4: Recording layer 5: Second protective layer Patent applicant: Teijin Ltd.
Attorney Patent Attorney Former 1) Junhiro (△)
(B) Spear 11￥ Tori Saizuzu

Claims (1)

[Scope of Claims] 1. In an optical recording medium having a recording layer made of a light-rewritable metal thin film on a substrate made of a transparent synthetic resin, at least the surface of the recording layer on the substrate side contains an easily oxidized metal or an alloy thereof. An optical recording medium characterized by being provided with a thin protective layer containing. 2. The optical recording medium according to claim 1, wherein the protective layer has lower thermal conductivity than the recording layer. 3. The optical recording medium according to claim 1 or 2, wherein the protective layer is a thin film containing at least titanium or zirconium. 4. The optical recording medium according to any one of claims 1 to 3, wherein the protective layer has a thickness of 50 Å or less. 5. The optical recording medium according to any one of claims 1 to 4, wherein the protective layer is also formed on a surface of the recording layer opposite to the substrate. 6. The optical recording medium according to any one of claims 1 to 5, wherein the protective layer is formed to cover an edge portion of the recording layer. 7. The optical recording medium according to claims 1 to 6, wherein the recording layer is a magneto-optical recording layer recorded by a magneto-optical effect. 8. The optical recording medium according to claim 7, further comprising a dielectric layer between the recording layer and the substrate. 9. The optical recording medium according to any one of claims 1 to 8, wherein the recording layer is a metal thin film containing iron. 10. An optical device that has a recording layer made of a thin metal film that can be rewritten by light on a transparent synthetic resin substrate, and a protective layer of a thin film containing an easily oxidized metal or an alloy thereof is formed on at least the surface of the recording layer on the substrate side. A method for manufacturing an optical recording medium, which comprises forming the protective layer and then forming the recording layer thereon without exposing the protective layer to the atmosphere. 11. The method for manufacturing an optical recording medium according to claim 10, wherein the protective layer and the recording layer are formed in the same vacuum chamber.