JP3429406B2 - Optical recording medium and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium and its manufacturing method.

[0002]

2. Description of the Related Art As a large-capacity information recording medium, an optical recording medium such as an optical recording disk is drawing attention. The optical recording medium includes a rewritable type such as a phase change type optical recording medium and a magneto-optical recording medium, and a write-once type such as a pit formation type optical recording medium.

In recent years, an optical recording disc has been proposed which is capable of reproducing and recording according to the compact disc (CD) standard. This optical recording disk is formed by forming a dye layer, an Au reflective layer and a protective film in this order on a transparent resin substrate. That is, the reflective layer is provided in close contact with the dye layer.

However, since this optical recording disk uses an organic dye, it has low weather resistance, particularly light resistance, and the dye is deteriorated by, for example, ultraviolet rays in sunlight. Therefore, it is difficult to perform reliable storage for a long period of time, both before and after recording. Further, the optical recording disk using the organic dye has a drawback that wavelength dependency is large.

Under the above circumstances, the present inventors
As an optical recording medium capable of reproducing in accordance with the standard and having high light resistance, an optical recording medium using silver oxide or iron nitride in a recording layer has been proposed (JP-A-4-298389).
5-40959 and 5-166225). In these optical recording media, irradiation of recording light decomposes silver oxide or iron nitride in the recording layer to generate gas. Then, the gas forms voids or recesses in the medium, changes the optical conditions, and forms recording marks.

Since an optical recording medium is required to maintain a stable recording state for a long period of time, for example, in JP-A-5-166225, Ni, Ti, Co and Cu are contained in a recording film containing Ag and O. At least one of
Durability is improved by adding seeds. It is considered that the improvement of the durability in the publication is due to the fact that Ag in a metallic state generated in the recording film at the time of recording is alloyed by combining with an additive element such as Ni, thereby stabilizing the recording state.

However, it is difficult for an optical recording medium whose durability is improved in this way to maintain a stable recording state for a long period of time under high temperature and high humidity. However, there is a problem that jitter, C / N, reproduction output and the like are easily deteriorated.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the durability when an optical recording medium having a recording film using silver oxide is stored under high temperature and high humidity.

[0009]

Such an object can be achieved by any of the following constitutions (1) to (5). (1) A recording film, a dielectric film, and a reflective film are provided in this order on the substrate surface, and the recording film contains Ag and O as main components and an element M (M is Sb, Pd, Pt) as a minor component. And at least one of C). (2) Content of the element M in the recording film is 0.2 to 10 atom%.
The optical recording medium according to (1) above. (3) A recording film, a dielectric film, and a reflective film are provided in this order on the surface of the substrate, the recording film contains Ag and O as main components, and the element M (M is Sb, Pd, Pt) as a minor component. And at least one of C), the method for producing an optical recording medium, wherein a recording film is formed by a reactive sputtering method using a target containing Ag or containing Ag and the element M. (4) The method for producing an optical recording medium according to the above (3), wherein the recording film is formed by performing reactive sputtering in an atmosphere containing oxygen gas and / or C-containing gas. (5) The content rate of the element M in the recording film is 0.2 to 10 atom%.
The method for producing an optical recording medium according to (3) or (4) above, which is for producing the optical recording medium.

[0010]

As shown in FIG. 1, the optical recording medium 1 of the present invention has the recording film 3 and the dielectric film 4 on the surface of the substrate 2.
And a reflective film 5.

At the time of recording, a recording laser beam is irradiated from the back side of the substrate 2 through the substrate 2 to heat the recording film 3. The main components of the recording film are Ag and O, and silver oxide composed of these decomposes into Ag and O _{2 at} about 160 ° C., so that gas is released from the recording film 3 by irradiation with the recording laser light. Then, the generated gas forms voids in the recording film 3. Further, since the resin substrate 2 near the recording film 3 is heated and softened, a recess is formed at the interface with the recording film 3 due to the pressure of the generated gas, and the recess and the void constitute a recording mark. To do.

The formation of these voids or recesses changes the optical conditions such as the optical constants and optical path lengths of the recording laser light irradiation portion, and reduces the reflectance.

Since the change of the light reflectance thus generated is irreversible, it can be used as a write-once type optical recording medium. And used for CD 7
The reflectance of light in the vicinity of 80 nm can be 65% or more in the unrecorded portion, 70% or more, and the modulation degree can be 30% or more.
It can be used as a write-once optical recording disc that can be reproduced by a player.

Further, by adjusting the thickness of the dielectric film or the like, such reflectance change can be obtained in the wavelength range of about 300 to 900 nm, so that recording / reproducing in a short wavelength range is possible. Higher recording density is possible.

Further, the optical recording medium of the present invention has a high recording sensitivity and can record with a low power laser beam of, for example, 8 mW or less.

Since the optical recording medium of the present invention does not use a substance having a low light resistance such as an organic dye, it has a very high light resistance, and there is almost no deterioration in characteristics due to light both before and after recording.

Since the recording film contains the above element M in addition to Ag and O, it is possible to maintain a stable recording state even when the recording film is stored at high temperature and high humidity for a long period of time after recording. Jitter, C / N, reproduction output, etc. are hardly deteriorated even after long-term storage under adverse conditions.
Specifically, among the elements M, Sb and C are considered to stabilize the recording state because they mainly form a covalent bond structure with Ag in the metallic state generated at the time of recording.
It is considered that t suppresses the diffusion and migration of Ag due to the bonding and alloying with Ag, and thereby stabilizes the recorded state and the unrecorded state more than Ni described above.

[0018]

Specific Structure The specific structure of the present invention will be described in detail below.

FIG. 1 shows a structural example of the optical recording medium of the present invention. The optical recording medium 1 has a recording film 3, a dielectric film 4 and a reflective film 5 in this order on a surface of a substrate 2, and a protective film 6 is provided on the reflective film 5.

<Substrate 2> In the optical recording medium 1, since the recording film 3 is irradiated with the recording light and the reproducing light through the substrate 2,
The substrate 2 needs to be substantially transparent to these lights. Moreover, since the substrate 2 needs to have a recess formed by the pressure of the gas generated from the recording film 3, a resin is preferable as the material of the substrate 2. Specifically, various resins such as acrylic resin, polycarbonate resin, epoxy resin, and polyolefin resin may be used. Note that a glass substrate provided with a resin layer by a so-called 2P method may be used as the substrate.

The shape and size of the substrate 2 are not particularly limited, but are usually disk-shaped, and their thickness is usually
The diameter is about 0.5 to 3 mm and the diameter is about 50 to 360 mm.

A predetermined pattern such as a groove is provided on the surface of the substrate 2 for tracking, addressing, etc., if necessary. For example, the optical recording medium of the illustrated example is provided with a groove, and the recording light is irradiated into the groove.

<Recording Film 3> The recording film 3 has A as a main component.
g and O, which are usually present as silver oxide in the recording film. The content ratio of O in the thin film is
It is preferably 5 to 70 atom%, particularly preferably 10 to 40 atom%.

The recording film 3 contains an element M (M is
At least one of Sb, Pd, Pt and C). The content of the element M in the recording film is preferably 10 atom% or less, more preferably 5 atom% or less. If the content of the element M is too high, the optical constant of the recording film changes greatly,
It may be difficult to obtain a sufficient reflectance as an optical recording medium. Further, in order to fully exert the effect of the addition, the content rate of the element M is preferably 0.2 atom% or more, more preferably 0.5 atom% or more. Among M, Pt is particularly preferable because it is highly effective even when the content is low.

The recording film has a thickness of 60 to 150 nm, especially 7
It is preferably 0 to 120 nm. If the recording film is too thin, recording will be difficult, and if it is too thick, the reflectance will be insufficient due to light absorption by the recording film.

The recording film 3 is preferably formed by a vapor phase growth method such as a sputtering method or a vapor deposition method, and particularly preferably formed by a reactive sputtering method using oxygen gas or the like as a reactive gas.

In the reactive sputtering method, a target containing Ag and the element M is usually used. In this case, an alloy target or a mixture target may be used, or a multi-source sputtering method using a plurality of targets may be used.
Also, at least one alloy target may be used in the multi-source sputtering method.

Oxygen gas is usually used as the reactive gas, but when C is contained as M in the recording film,
A carbon-containing gas such as carbon dioxide gas or hydrocarbon gas may be used. Carbon dioxide is preferable as the C-containing gas in this case. A C-containing gas capable of forming silver oxide in reactive sputtering targeting Ag, such as carbon dioxide gas, is
Oxygen gas may or may not be used in combination, but in the case of a C-containing gas that cannot form silver oxide alone, oxygen gas is usually used together. It should be noted that C can be supplied from the target or both the target and the C-containing gas. The oxygen gas and the C-containing gas are preferably used together with an inert gas such as Ar.

The flow rate of gases capable of forming silver oxide, such as oxygen gas and carbon dioxide gas, is 10 in the total flow rate of all gases.
It is preferably set to 70%. If this flow rate is out of the above range, the amount of oxygen in the recording film becomes unsuitable, and sufficient recording sensitivity cannot be obtained.

The pressure during the reactive sputtering is preferably 3
× 10 ^{−1 to} 3.0 Pa, more preferably 5 × 10 ⁻¹ to 1.
It is 0 Pa.

DC sputtering may be used for the reactive sputtering, but high frequency sputtering is preferably used.

<Dielectric Film 4> The dielectric film 4 is provided for adjusting the reflectance of the medium and controlling various phenomena that occur near the recording film during recording.

The dielectric film 4 is composed of various dielectrics. The dielectric used is not particularly limited, but preferably has a high film forming rate, a high refractive index, a high hardness, and a low thermal conductivity. Specifically, various oxides, nitrides, and sulfides such as silicon oxide and silicon nitride, and mixtures containing two or more kinds of these, such as silicon oxide-zinc sulfide, La, Si, O, and N are contained. So-called SiAlON containing LaSiON, Si, Al, O and N, SiAlON containing Y
Etc., or glass or the like may be appropriately selected. However, if it is made of silicon oxide, the recording sensitivity is improved. As the silicon oxide, it is usually preferable to use one having a composition represented by SiO ₂ .

The thickness of the dielectric film 4 may be appropriately set according to the refractive index of the dielectric used, and for example, when SiO ₂ is used as the dielectric, it is preferably 50 to 400 nm, more preferably 180 to 350 nm. , And more preferably 25
It is 0 to 330 nm. Further, when a dielectric having a refractive index different from that of SiO ₂ is used, a preferable thickness is the above-mentioned SiO obtained by dividing the refractive index of SiO _{2 by} the refractive index of the dielectric.
_It may be obtained by multiplying the preferable thickness range of ₂ . If the thickness of the dielectric film 4 is out of the preferable range, it becomes difficult to obtain a sufficient reflectance and its change.

The dielectric film 4 is preferably formed by a vapor phase growth method such as a sputtering method or a vapor deposition method.

<Reflective Film 5> The reflective film 5 is provided to maintain the reflectance of the medium.

The reflective film 5 is preferably composed of a metal or alloy having a high reflectance, such as Ag, Al, Au,
It may be appropriately selected from Pt, Cu and the like.

The thickness of the reflective film 5 is preferably 30 to 150 nm. If the thickness is less than the above range, it becomes difficult to obtain sufficient reflectance. Further, even if it exceeds the above range, the improvement in reflectance is small, which is disadvantageous in terms of cost.

The reflective film 5 is preferably formed by a vapor phase growth method such as a sputtering method or a vapor deposition method.

<Protective Film 6> The protective film 6 is preferably provided in order to improve scratch resistance and corrosion resistance. Protective film 6
Is preferably composed of various organic substances, but is particularly preferably composed of a substance obtained by curing a radiation-curable compound or a composition thereof with radiation such as electron beams or ultraviolet rays.

The thickness of the protective film 6 is usually 0.1-100.
It is about μm, and it may be formed by a usual method such as spin coating, gravure coating, spray coating, or dipping.

<Plastic Deformation Layer 7> In the present invention, as shown in FIG. 2, a plastic deformation layer 7 may be provided between the substrate 2 and the recording film 3 if necessary. By providing the plastically deformable layer, it is possible to suppress deterioration of characteristics such as jitter, reproduction output and C / N during long-term storage under high temperature and high humidity.

When the plastic deformation layer is not provided, elastic deformation contributes to the formation of the concave portion on the resin substrate in addition to the plastic deformation, so that the concave portion is likely to return with the passage of time. Further, when a long signal is recorded, the bottom shape of the recess is likely to be non-uniform, so that the jitter immediately after recording (initial stage) is likely to be large. In addition, when the shape of the bottom surface of the recess is non-uniform, the stress in the recess is also non-uniform, so that the shape change over time easily occurs. Therefore, in the conventional medium having no plastic deformation layer, deterioration easily occurs due to long-term storage, and there is room for improvement in initial characteristics.

On the other hand, when the plastic deformation layer 7 is provided, the deformation amount of the substrate is reduced as a result of the deformation of the plastic deformation layer 7, and the return amount of the substrate is reduced. Further, since there is almost no elastic element in the deformation of the plastic deformation layer, the plastic deformation layer suppresses the returning of the substrate. Further, by providing the plastically deformable layer, the shape of the bottom surface of the recess is also improved, so that both the initial characteristics and the characteristics after aging are improved.

The plastically deformable layer is preferably any one of the following, more preferably:

As the coating organic titanate containing a hydrolyzate of an organic titanate, various compounds capable of forming an oxide by hydrolysis can be used, and in particular, a substituted or unsubstituted alkyl titanate, a substituted or unsubstituted alkyl titanate, Unsubstituted alkenyl titanate esters are preferred. Of these, particularly preferred are compounds represented by the following formula.

Formula Ti (OR ₁ ) (OR ₂ ) (OR ₃ ) (OR ₄ )

In the above formula, R ₁ , R ₂ , R ₃ and R ₄ represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a hydrogen atom. However, at least two or more of R _{1 to} R ₄ are preferably other than hydrogen atoms. In addition, the substituted or unsubstituted alkyl group and the substituted or unsubstituted alkenyl group preferably have 2 to 18 carbon atoms. As the group substituting the alkyl group or the alkenyl group, a substituted amino group such as a carboxyl group, an alkylcarboxyl group and a di (hydroxyalkyl) amino group, a hydroxyl group, an alkyloxycarbonyl group and the like are preferable.

Preferred specific examples include T1 tetraethyl titanate, T2 tetrapropyl titanate and T
3 tetraisopropyl titanate, T4 tetra (n
-Butyl) titanate, T5 tetra (isobutyl) titanate, T6 tetra (sec-butyl) titanate, T7 tetra (tert-butyl) titanate, T
8 Tetra (2-ethylhexyl) titanate, T9
Tetrastearyl titanate, T10 hydroxytitanium stearate, T11 isopropoxytitanium stearate, T12 hydroxytitanium oleate, T13 isopropoxytitanium oleate,
T14 di-i-propoxy bis (acetylacetone) titanate, T15 di-n-butoxy bis (triethanolamine) titanate, T16 dihydroxy bis (lactic acid) titanate, T17
Tetraoctylene glycol titanate, T18 di-
Examples thereof include i-propoxy bis (ethyl acetoacetate) titanate, among which T3, T4, T
5 is preferable.

Each of the above compounds may form an oligomer.

In order to form a plastically deformable layer using such an organic titanate, the organic titanate is dissolved in a solvent such as water, alcohol, hexane, benzene or a mixture thereof, and the solution is applied to the substrate. Then, hydrolysis may be carried out by leaving it to stand. In this case, the hydrolysis may be promoted by heating in an oven or the like, but the heating temperature in that case is preferably about 80 ° C. or lower which does not affect the resin substrate. The degree of hydrolysis is not particularly limited, but is preferably 60% or more. If the hydrolysis is insufficient, the change with time after forming the optical recording medium may become large. The degree of hydrolysis is
It can be measured by FTIR or the like.

Of colloidal particle dispersion of silicon-based condensate
Coating film containing hydrolyzate Colloidal particles of silicon-based condensate are silicon halides,
In particular, hydrolytic condensation products of silicon tetrachloride or alkyl silicic acid, especially tetra-lower alkyl (methyl, ethyl) silicic acid are preferable. The colloidal particle size is preferably 3 to 1
It is 0 nm, more preferably 5 to 8 nm. As the dispersion medium, alcohols, particularly monohydric aliphatic alcohols, alkyl acetates, or mixed solvents of these and aromatic hydrocarbons are preferable. In addition, for hydrolysis, a mineral acid is added as needed. In addition, a stabilizer such as ethylene glycol or a surfactant is added, if necessary.

As an example of such a colloidal particle dispersion, silicon tetrachloride (SiCl ₄ ) described in Japanese Patent Publication No. 31-6533 and a monovalent aliphatic alcohol are dissolved in an alkyl acetate ester. There is something. Further, a solution containing tetraalkylsilicic acid, a monohydric aliphatic alcohol, an alkyl acetate and a mineral acid described in JP-B-36-4740 may be added with 1 to 20% by weight of ethylene glycol. In addition, Japanese Patent Publication No. 45-3543
You may use the alcohol solution of the 4 lower alkyl silicic acid described in the gazette.

Examples of the monohydric aliphatic alcohol include methyl alcohol, ethyl alcohol, denatured alcohol,
Isopropyl alcohol, butyl alcohol, and mixtures thereof are preferable, and as the alkyl acetate,
Methyl acetate, ethyl acetate, amyl acetate, butyl acetate,
A mixture of these is preferable, and the mineral acid is preferably an aqueous solution of hydrochloric acid or sulfuric acid.

The above-mentioned dispersion liquid may be applied by a usual method such as spin coating, and the coating film is dried by 40 to 8
It is preferable to perform the treatment at about 0 ° C. for about 20 minutes to 2 hours. If the drying temperature is too high or the drying time is too long, hydrolysis proceeds too much and the hardness of the coating film increases, and the function as the plastic deformation layer becomes insufficient. On the other hand, if the drying temperature is too low or the drying time is too short, residual coating solvent may be a problem, and hydrolysis may be insufficient and changes over time may easily occur.

A coating containing a hydrolyzate of an organic aluminate.
As the film organic aluminate, a substituted or unsubstituted alkyl aluminate ester or a substituted or unsubstituted alkenyl aluminate ester is preferable. Of these, particularly preferred are compounds represented by the following formula.

Formula Al (OR ₁ ) (OR ₂ ) (OR ₃ )

In the above formula, R ₁ , R ₂ and R ₃
Is the same as in the formula exemplified in the description of the organic titanate.

As a preferred specific example, Al (O-i-
C₃ H₇ )₃ , Al (O-sec-C_Four H₉ )₃ etc
Among these, especially Al (O-sec-C
_Four H ₉ )₃ Is preferred.

Each of the above compounds may form an oligomer.

To form a plastically deformable layer using such an organic aluminate, hydrolysis may be carried out in the same manner as the above-mentioned organic titanate.

A coating containing a hydrolyzate of an organic zirconate.
The membrane organic zirconate is preferably a substituted or unsubstituted alkyl zirconate ester or a substituted or unsubstituted alkenyl zirconate ester. Of these, particularly preferred are compounds represented by the following formula.

Formula Zr (OR ₁ ) (OR ₂ ) (OR ₃ ) (OR ₄ )

In the above formula, R ₁ , R ₂ , R ₃ and R ₄ are the same as those in the formula exemplified in the description of the organic titanate.

A preferred specific example is Zr (O-n-
C ₃ H _{7) 4} and the like.

Each of the above compounds may form an oligomer.

To form a plastically deformable layer using such an organic zirconate, hydrolysis may be carried out in the same manner as the above-mentioned organic titanate.

Fluororesin layer or polyimide layer These are all formed by the sputtering method. Examples of the fluororesin include polytetrafluoroethylene, polytrifluoroethylene chloride, polyvinylidene fluoride, polyvinyl fluoride, tetrafluoroethylene-hexafluoropropylene copolymer resin, tetrafluoroethylene-ethylene copolymer resin, trifluoroethylene. Fluorinated chloroethylene-ethylene copolymer resin and the like are preferable. As the polyimide, for example, aliphatic polypyromellitimide, aromatic polypyromellitimide, polyetherimide, polyaminobismaleimide, etc. are preferable.

The thickness of the plastically deformable layer is preferably 40 to 2
00 nm, more preferably 80 to 150 nm. If the plastic deformation layer is too thin, the effect of improving durability is insufficient, and if the plastic deformation layer is too thick, there is a risk of filling up the tracking groove or the like on the substrate surface.

<Reflectance changing action> When the recording laser light is irradiated from the back surface side of the substrate 2 of the optical recording medium 1 having the structure shown in FIG. 1, the recording laser light transmitted through the substrate 2 is recorded on the recording film 3.
To heat. The silver oxide in the recording film 3 is heated to generate Ag and O.
It is decomposed into ₂ and O ₂ gas is generated. Then, voids are formed in the recording film 3 due to the pressure of the generated gas.

On the other hand, as the temperature of the recording film 3 rises, the recording film 3
The temperature of the substrate 2 in the vicinity also rises, and the substrate 2 softens. The pressure of the generated gas causes the substrate 2 in the configuration of FIG.
2 deforms, and in the configuration of FIG. 2, the plastic deformation layer 7 deforms and the surface of the substrate 2 deforms, so that a concave portion is formed on the surface of the substrate or the surface of the laminated body including the substrate and the plastic deformation layer. In some cases, the dielectric film 4 side may also be dented due to the pressure of the gas. In the configuration of FIG. 2, since the plastic deformation layer 7 is not elastically deformed, there is almost no return to this deformation. It is considered that in the vicinity of the bottom surface of the recess in the configuration of FIG. 2, a part of the plastic deformation layer constituent material moves to the periphery of the recess, and the thickness of the plastic deformation layer is reduced.

In the void formed by the irradiation of the recording laser light, the refractive index n (real part of complex refractive index) and the extinction coefficient k
Since the optical constants such as (imaginary part of complex refractive index) are different from those in the recording film 3 and the optical path length is changed due to the presence of the concave portion, the multiple reflection condition is changed and the reflectance is remarkably increased in the recording laser light irradiation portion. descend.

The recess has a depth of about 50 to 150 nm, especially 5
It is about 0 to 80 nm, and the dimensions can be measured by a scanning electron microscope (SEM), a scanning tunnel microscope (STM), or the like.

<Medium Structure> In the above description, the present invention is applied to a single-sided recording type optical recording medium capable of reproduction corresponding to the CD standard. However, the present invention is also applicable to a double-sided recording type optical recording medium. Applicable.

When applied to a double-sided recording type optical recording medium,
A pair of single-sided recording media may be bonded so that the recording film 3 is enclosed.

Further, it is also possible to adopt a single-sided recording type in which a protective plate is adhered on the protective film 6. In this case, the protective plate may be made of the same material as the substrate 2, but it does not have to be transparent, and other materials can be used.

[0077]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention.

Example 1 A recording film 3, a dielectric film 4 composed of silicon oxide and zinc sulfide, a reflective film 5, and an ultraviolet-curable resin protective film 6 are formed on the surface of a substrate No. 1 of Sample No. 1. Then, an optical recording disk sample No. 1 having the structure shown in FIG. 1 was produced.

For the substrate 2, a disc-shaped polycarbonate resin having a diameter of 120 mm and a thickness of 1.2 mm in which grooves were simultaneously formed by injection molding was used.

The recording film 3 was formed to a thickness of 90 nm by a reactive high frequency sputtering method in an atmosphere containing oxygen gas and Ar gas. The pressure during sputtering was 0.5 Pa, the flow rate of oxygen gas was 10 SCCM, and the flow rate of Ar gas was 11.5 SCCM. Note that this flow rate is a display based on nitrogen gas.
As the target, Ag to which Sb chip and Pd chip were attached was used. Table 1 shows the contents of Sb and Pd in the recording film 3. This composition was measured by EPMA and XRF.

The dielectric film 4 was formed by a sputtering method using a ZnS-SiO ₂ composite as a target. The molar ratio was 50:50 and the thickness was 230 nm.

The reflective film 5 was formed to a thickness of 100 nm by a sputtering method using Au as a target.

The protective film 6 was formed by applying an ultraviolet curable resin by spin coating and then curing it by irradiating it with ultraviolet light. The thickness after curing was 5 μm.

Sample Nos. 2 and 3 were formed in the same manner as Sample No. 1 except that Ag to which a Pt chip was attached was used as a target when the recording film was formed.

The sample No. 4 recording film was formed by a reactive high frequency sputtering method in an atmosphere containing CO ₂ gas and Ar gas. The pressure during sputtering is 0.5 Pa, the flow rate of CO ₂ gas is 10 SCCM, A
The flow rate of r gas was 11.5 SCCM. Note that this flow rate is a display based on nitrogen gas. The target is Ag
Was used. The other manufacturing conditions were the same as those of Sample No. 1.

Sample No. 5 (Comparative Example) Sample except that an Ag target was used when forming the recording film.
It was produced in the same manner as No. 1.

Sample No. 6 (Comparative Example) Sample No. 1 was formed in the same manner as in Sample No. 1 except that Ag to which a Ni chip was attached was used as a target when the recording film was formed.

EFM signals were recorded for each of the above samples. As the recording light, laser light having a wavelength of 780 nm was used with an output of 8 mW. Each sample after recording, 60 ℃ ·
After storing in an environment of 90% RH for 50 hours, the EFM signal was reproduced and the signal quality was evaluated according to the following criteria. Laser light with a wavelength of 780 nm is output as reproduction light.
Used at 0 mW. The results are shown in Table 1.

◯: The eye pattern of the reproduced waveform of the EFM signal is opened, and no bleeding is observed at the R bottom of the eye pattern. X: The eye pattern is open, but bleeding is recognized on the R bottom.

Further, each sample after recording was processed at 60 ° C./9
The sample was stored in an environment of 0% RH for 50 hours, and the reflectance (retention rate of reflectance) after storage with respect to the initial reflectance was examined. The results are shown in Table 1.

[0091]

[Table 1]

From Table 1, it can be seen that by adding the element M to the recording film, the durability under high temperature and high humidity is significantly improved.

When the Pt content of the recording film was set to 13.2 atomic%, the initial reflectance became low and reproduction with a CD player became impossible.

Example 2 An optical recording disk sample having the structure shown in FIG. 2 was produced.

The plastic deformation layer 7 was formed by spin coating a coating film of a solution prepared by dissolving 2% by weight of tetra (n-butyl) titanate in ethyl cellulose, and drying this in an oven at 60 ° C. for 3 hours. It was formed by allowing it to cool for 30 minutes. The degree of hydrolysis of the coating film after drying was 63%. The degree of hydrolysis was determined from the FTIR measurement results of the coating film formed on KBr and dried under the above conditions. The thickness of the plastic deformation layer is
It was 120 nm. This thickness was determined from a scanning electron micrograph of the cross section of the coating film.

Sample N of Example 1 except for the plastically deformable layer
o. Formed as in 1. After recording the EFM signal to this sample and storing it in the environment of 60 ° C and 90% RH for 100 hours, when the EFM signal was reproduced, the eye pattern of the reproduced waveform was opened and the R bottom of the eye pattern was opened. No bleeding was observed.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a configuration example of an optical recording medium of the present invention.

FIG. 2 is a partial cross-sectional view showing a configuration example of an optical recording medium of the present invention.

[Explanation of symbols]

1 Optical recording medium 2 substrates 3 recording film 4 Dielectric film 5 Reflective film 6 protective film 7 Plastic deformation layer

Front page continuation (72) Inventor Tsuneo Kuwahara 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Corporation (56) Reference JP-A-5-166225 (JP, A) JP-A-4-298389 ( JP, 5-40959 (JP, A) JP, 3-114778 (JP, A) JP, 5-169819 (JP, A) JP, 8-306071 (JP, A) (58) ) Fields surveyed (Int.Cl. ⁷ , DB name) B41M 5/26 G11B 7/24

Claims (5)

(57) [Claims] 1. A recording film, a dielectric film, and a reflective film are provided in this order on a substrate surface, the recording film contains Ag and O as main components, and an element M (M is Sb, Pd as a sub-component). ,
An optical recording medium containing at least one of Pt and C). 2. The content of the element M in the recording film is 0.2 to 1.
The optical recording medium according to claim 1, wherein the content is 0 atomic%. 3. A recording film, a dielectric film, and a reflective film are provided in this order on the surface of the substrate, and the recording film contains Ag and O as main components and an element M (M is Sb, Pd as a minor component). ,
A method of manufacturing an optical recording medium, which comprises forming a recording film by a reactive sputtering method using a target containing Ag or a target containing Ag and the element M when manufacturing an optical recording medium containing at least one of Pt and C). 4. The method of manufacturing an optical recording medium according to claim 3, wherein the recording film is formed by performing reactive sputtering in an atmosphere containing oxygen gas and / or C-containing gas. 5. The content of the element M in the recording film is 0.2 to 1.
An optical recording medium containing 0 atomic% is manufactured.
Optical recording medium manufacturing method.