JPS6232088A - Preparation of optical recording medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to the use of light such as laser light (light here refers to various energy rays including the above-mentioned laser light).
The present invention relates to a method of manufacturing an optical recording medium for recording and reproducing information.

[Prior Art] Various optical recording media have been proposed in which information is recorded and reproduced by irradiating a thin film layer formed on a substrate with laser light.

For example, an optical recording layer made of a thin film of a low melting point metal such as Tomasu 81 or Tellurium Te is formed, and this is irradiated with laser light to melt and evaporate it to form recording bits and record information. There is something.

However, in order to form recording bits in this recording format, a laser beam with high power is required, and there is a drawback that the shape of the formed recording bits is not uniform. As a result, it is easy to cause noise when recording is reproduced, and it is difficult to obtain a stable reproduced signal, that is, it is difficult to achieve high-density recording.

To form such an optical recording layer, film forming methods such as vacuum evaporation method, spuckling method, ion blating method, plasma CVD method, thermal CVD method, and photoCVD method have been tried, and generally, sputtering method is used. is widely used and even commercialized.

The optical recording layer obtained by these film forming methods is S/
In terms of productivity and mass production, we are developing more comprehensive characteristics, including N ratio, optical characteristics, usage environment characteristics, storage environment characteristics, and even characteristics as an optical recording medium such as uniformity and reproducibility. Improvement is needed.

However, the conventional method of forming an optical recording layer by sputtering has had the following problems.

In other words, in the sputtering method, there are many formation parameters (e.g. substrate, sputtering pressure, high frequency power, target-substrate distance, pumping speed, substrate rotation speed, etc.). becomes unstable and often gives a significant bad shadow 1# to the formed optical recording layer.

In addition, snowmaking-specific parameters had to be selected for each device. In addition, there were other problems such as the surface of the optical recording layer becoming rough, and the film quality at the interface between the optical recording layer and the substrate being particularly susceptible to deterioration, and furthermore, the temperature of the substrate rose during film formation, leading to a decrease in film quality. .

As described above, with the conventional method, mass production with excellent reproducibility cannot be achieved while satisfying uniformity of quality and environmental characteristics of the optical recording layer.

[Problems to be Solved by the Invention] It is an object of the present invention to eliminate the above-mentioned drawbacks of the conventional optical recording medium manufacturing method, particularly the drawbacks of the sputtering method, and at the same time to solve the problems of the conventional optical recording medium manufacturing method. The object of the present invention is to provide a novel method for manufacturing an optical recording medium that does not require the following steps.
1. Another object of the present invention is to easily mass-produce optical recording media that can improve the storage characteristics of optical recording media, particularly have low media noise, and have excellent storage environment characteristics. The object of the present invention is to provide a method for manufacturing an optical recording medium that allows the following.

[Means for Solving the Problems] The present invention achieves the above object by applying the following general formula (^), which is a raw material for forming an optical recording layer, into a film forming space for forming an optical recording layer on a substrate. At least one compound represented by
Introducing an active species that chemically reacts with the compound,
By evaporating metal sulfide, which is still another raw material for forming the optical recording layer, in the film forming space almost simultaneously, a metal M derived from the compound of general formula (A) is added to the metal sulfide on the substrate. This is a method for producing an optical recording medium characterized by forming an optical recording layer in which are dispersed.

RnMm...(A) (However, m is a positive integer equal to the valence of day or an integral multiple, n is a positive integer equal to the valence of M or an integral multiple,
M represents a metal element, and H represents hydrogen, halogen, or a hydrocarbon group. Embodiments of the Invention A typical example of an optical recording medium formed by the method of the present invention is shown in FIG.

In the optical recording medium shown in FIG. 2, reference numeral 1 denotes a substrate made of various materials such as glass and plastic.

4 is an optical recording layer formed by the method of the present invention,
The optical recording layer 4 has a metal 3 derived from the compound of the general formula (A) in the metal sulfide 2 (i.e., a metal 3 derived from the compound of the formula (A)).
M”) are dispersed.

Specifically, the metal 3 includes Te, Bi, Sn,
In, Pb, Cu, Ti, Zr, Ta, Au
, Pt, Ss, zn, etc., and one or more of these metals include SnS, 5b2S, Gem, Asp.
SA, WS2, An2s3, In2S3, A92S
.

CrS, Cod, TaS2, CLI2S,
An optical recording layer 4 is formed by being dispersed in a metal sulfide 2 made of one or more of PbS, Bi253, MnS, MoS, etc.

For example, Ar-Ne laser,
When irradiated with recording light of various wavelengths including laser light from a semiconductor laser, the optical properties of the optical recording layer 4 made of metal sulfide 2F3 and metal 3 (for example, reflectance, transmittance,
(refractive index, etc.) changes, creating an optical difference between the areas irradiated with the recording light and the areas that are not irradiated.
Recording is done. Reproduction of recording is performed by irradiating the recorded portion with reproduction light such as the laser beam described above and detecting optical differences in the optical recording layer.

In an optical recording medium having such an optical recording layer, high-density recording is possible because recording and reproduction do not depend on the formation of recording bits. Moreover, since the metal sulfide forming the optical recording layer has excellent storage stability, the optical recording layer is prevented from deteriorating over time, and an optical recording medium with excellent durability can be obtained.

Although not shown in FIG. 2, the substrate 1 may be provided with so-called guide grooves as necessary for the purpose of improving recording efficiency, etc. Also, a Ti adhesion layer and an antireflection layer may be provided on the substrate 1. Alternatively, various functional layers widely known in this type of technology, such as a protective layer, may be provided between the substrate and the optical recording layer or on the optical recording layer.

Next, the method of the present invention will be explained in detail.

The "active species" as used in the present invention refers to species that chemically interact with the compound (A) and, for example, give energy to the compound (A) or chemically react with the compound (A). It refers to a substance that plays a role in making the metal rMJ derived from compound (A) into a state in which it can be dispersed in an optical recording layer.Therefore, as an "active species", it refers to a component constituting the optical recording layer to be formed. It may contain or may not contain such components.

The compound (A) represented by the general formula (A) used in the present invention is a compound whose metal portion, ie, "M", can be a constituent of an optical recording layer.

These compounds cause a chemical reaction by molecular collision with the above-mentioned active species in the space where the substrate on which the film is formed exists, and metal rMJ, which is a component of the optical recording layer formed on the substrate, is produced. It is more desirable to select one that spontaneously generates a chemical species that contributes to the formation of. However, in their normal state of existence, the above-mentioned active species may be inactive or
Or! If the compound (A) does not have such activity, excitation energy strong enough to not completely dissociate the metal MJ, which is its constituent component, is applied to the compound (A) before or during film formation. !It is necessary to bring the compound into an excited state capable of chemically reacting with the active species, and a compound capable of producing such an excited state t@1 is employed as the compound (A) used in the method of the present invention. be.

In the present invention, compounds in which the compound (A) is in the above-mentioned excited state will hereinafter be referred to as "excited species."

In the present invention, the compound (A) represented by the general formula (A)
Examples of compounds that can be effectively used as "rRnMm" include the following compounds.

That is, "M" is a metal element, specifically Te, 8L, S
n, In, Pb, Cu, Ti%Zr, Ta,
One or more types of Au, Pt%Se, 2n, etc. are used.

rRJ includes monovalent, divalent and trivalent hydrocarbon groups derived from [11[]-like and side chain saturated hydrocarbons and unsaturated hydrocarbons, or saturated or unsaturated monocyclic and polyvalent hydrocarbon groups. Mention may be made of monovalent, divalent and trivalent hydrocarbon groups derived from cyclic hydrocarbons.

The unsaturated hydrocarbon group includes not only a single type of carbon-carbon bond, but also those having at least 2 fl of the - double bond, double bond, and double bond. Any method can be effectively adopted as long as it is suitable for achieving the purpose of the invention.

Further, in the case of an unsaturated hydrocarbon group having a plurality of double bonds, it does not matter whether the double bonds are non-integrated double bonds or integrated double bonds.

Examples of acyclic hydrocarbon groups include alkyl groups, alkenyl groups,
Alkynyl group, alkylidene group, alkylidene group, alkynyl group, alkynyl group, alkylidene group, alkynyl group V! In particular, the number of carbon atoms is preferably 1 to 10, more preferably 1 to 7, and most preferably 1 to 5.

In the present invention, the above-listed "R" and "R" are selected so that a compound (A) that is effectively used is selected to be a compound that is gaseous in a standard state or that can be easily vaporized in the usage environment. In selecting "M", a combination of "8" and "M" is selected as desired.

In the present invention, specific compounds that can be effectively used as the compound (^)- include 2nMe3.7nEt3,
Me, Se, Me2Te, Eb Se, Et2
Te, 5eX2.5eXn, SeX, , TeX, ,H
,,Se.

8 iX3, SnX*, PbEt*, CuX3, Ti
X4.2rL, TaX5, (PtX2)2(Go)3
, H2Te, etc. In the above, X
is halogen (F, C1,8r, I), Me is methyl group,
Et represents an ethyl group.

In the present invention, metal sulfides which are constituents of the optical recording layer include SnS, 5
b2S, GeS, AS2S3, ws2, kl,
Sj.

In, S3, A9. S, CrS, CoS,
TaS2, Cu>S.

Examples include PbS, 8i2S3, MnS, MoS, etc. One or more of these metal sulfides are appropriately selected and evaporated in the film forming space to form an optical recording layer together with the metal "M" described above.

In the method for producing an optical recording medium of the present invention, the above-mentioned compound (A
) and active species are introduced, and the metal sulfide is evaporated almost simultaneously within the film forming space. That is, the metal sulfide evaporated in the film forming space is deposited on the substrate, and the compound (A) introduced into the film forming space is
The nearly simultaneous deposition of metal "M" onto the substrate caused by the reaction between the compound (A) and the active species forms an optical recording layer in which the metal rMJ derived from the compound (A) is dispersed in the metal sulfide.

Compound (A) introduced into the film forming space by this method
And live'I! Even as a species, a chemical reaction occurs due to mutual collisions at the molecular level, and a compound (
When each of the metals capable of producing the metal "M" derived from A) is selected from among those listed above,
It is possible to obtain an optical recording medium in which metal "M" is dispersed in the optical recording layer. However, depending on the selection of the compound (A) and the active species, the above chemical reactivity may be poor, or the chemical reaction may be carried out more effectively.
In order to efficiently generate the metal "M" in the optical recording layer, the reaction promoting energy acting on the compound (A) and/or the active species in the film forming space, for example, is used in the activation space mentioned above. There is no problem in using the same activation energy as .

Furthermore, before introducing the compound (^) into the film forming space, the compound (A) is brought into the above-mentioned excited state f in another activation space.
For rubbing, one excitation energy may be applied.

The compound (A) may be introduced into the film forming space in an excited state as described above, or may be introduced without being in an excited state at all.

On the other hand, since the active species must already have activity when introduced into the film-forming space, the introduction is carried out as follows, that is, the activity f! By applying activation energy such as heat, light, or electric discharge to the raw material to be generated in an activation space different from the film-forming space, activated fl is generated, and this active species is introduced into the film-forming space. .

Introduced into the activation space, the activation f! The raw materials to produce it and l
, T 1et-Koshil -< 1. t'IC-a
tt (r) V If ” Substances that can be used as IR111754 can include substances that generate hydrogen radicals, and specific examples include H2, D2, HD, etc.
In addition, rare gases such as He and Ar can also be used.

Specifically, the activation energy that causes an activation effect on the active species generating substance in the activation space includes thermal energy such as resistance heating and infrared heating, light energy such as laser light, mercury lamp light, and halogen lamp light, and microscopic energy. wave,
RF, low frequency, electrical energy using discharge such as OC, etc. can be mentioned, and these activation energies may be applied alone to the active species generating substance in the activation space, or two or more types of activation energy may be applied to the active species generating substance. may be used in combination.

In addition, in the present invention, the activated species generated in the activation space are not only excited and activated by energy such as electric discharge, light, heat, etc., or a combination thereof, as described above, but also by contact with a catalyst, etc. Alternatively, it may be generated by addition.

In the present invention, the ratio between the total amount of compound (A) introduced into the film forming space and the amount of active species introduced from the activation space depends on the film forming conditions, the types of compound (A) and active species, and the desired light intensity. Although it can be determined as desired depending on the characteristics of the recording layer, it is preferably 1000:1 to 1:1 (introduction flow rate ratio), and more preferably 500:1 to ]:5.

When the active species does not cause a chain chemical reaction with compound (A), the ratio of the introduced amount is preferably 10:1 to 1.
The internal pressure of the film formation space during film formation, which is preferably 1:10, more preferably 4:1 to 2:3, is determined according to the selected types of compound (A) and active species, film formation conditions, etc. Although determined appropriately, preferably lXl0-2-5
xlO3Pa, more preferably 5xlO' to 1 xl
O3Pa, most preferably 1X10'' to 5XI02Pa.

In addition, in the present invention, it is possible to heat the substrate during film formation as necessary for various purposes such as increasing the homogeneity of film quality. The substrate temperature is preferably 50 to 1000°C,
More preferably 100-900°C, optimally 100-900°C
Desirably, the temperature is 750°C.

When the active species used in the present invention undergoes a chain reaction with compound (A), a so-called initiator (initiator) is used.
Since it is sufficient to minimize its function as a 1ater), the amount introduced into the film forming space is as follows:
It is sufficient to secure an amount sufficient to efficiently cause a chain reaction of chemical reactions.

The lifetime of the active species used in the present invention is preferably shorter in consideration of reactivity with compound (A), and longer in consideration of ease of handling during film formation and transport to the film formation space. The lifetime of the active species also depends on the internal pressure of the film forming space.

Therefore, the active species used should be selected and determined in such a way that an optical recording layer with the desired characteristics can be effectively obtained, taking production efficiency into account. An active species having the following properties is appropriately selected and used.

The active species used in the present invention has a lifetime of
The active species having a lifespan appropriately selected in view of the above points is appropriately selected as desired from within the compatible range of chemical affinity with the compound (A) specifically used, but preferably, Its lifespan is 1 x 10゛4 seconds or more, more preferably 1
It is desirable that the time be at least 10' seconds, most preferably at least 1X10' seconds.

Having such a long life increases the efficiency of the chemical reaction with the compound (A) introduced into the film forming space.

The method of introducing the compound (A) and active species into the film forming space is, for example, by providing a transport pipe connected to the film forming space,
The transport pipe may be introduced through the transport pipe, or the transport pipe may be extended to near the film forming surface of the substrate installed in the film forming space, and the transport pipe may be introduced with a nozzle-shaped tip. Double the tubes and use the inner tube for one side and the outer tube for the other side.
That is, for example, the active species may be transported in the inner pipe and at least one compound (A) may be transported in the outer pipe to be introduced into the film forming space.

In the method of the present invention, the metal sulfide that forms the optical recording layer together with the metal "M" described above, when the compound (A) and the active species are introduced into the film-forming space (almost simultaneously within the space). evaporated.

For the evaporation of metal sulfides, the evaporation raw water such as a Knudsen cell is installed in the film formation space, and the metal sulfide is evaporated.
It is preferable to carry out the process so that the production rate of the optical recording layer composed of "M" and metal sulfide is 0.01 to 1 m/min.

A schematic diagram of an example of an apparatus for carrying out the method of the present invention is shown in FIG.

The main parts of this device include a film forming chamber 9 (corresponding to a film forming space), an evaporation source 8 disposed within the chamber 9, and an activation chamber 10 (corresponding to between the activation chambers). It is configured. 5 and 6 are gas introduction pipes, and the compound (A) is introduced into the film forming chamber 9 through the gas introduction pipe 5. Further, the active species raw material is introduced into the activation chamber 10 through the gas introduction pipe 6, and after being activated in the chamber 10, the active species enters the film forming chamber 9. Note that 7 is a base body installed in the film forming chamber 9, and 11 is a gas exhaust system including a vacuum pump and the like for maintaining the inside of the film forming chamber 9 at a desired pressure.

[Function] The active species used in the present invention is introduced into the film forming space at the same time when forming the optical recording layer in the film forming space, and the active species is introduced into the film forming space at the same time as the metal "MJ" which is a component of the formed optical recording layer. chemically interacts with the compound (A) containing the compound (A) and the excited species (A) of the compound (A). Deposited on 7. As a result, a desired optical recording layer 4 in which metal "M" is dispersed in metal sulfide is easily formed on a desired substrate.

In the method of the present invention, the optical recording layer is formed by evaporating a metal sulfide, which is one component of the optical recording layer, in a film-forming space, and by evaporating the metal ``MJ'', which is another component, into the metal sulfide. “M” is introduced into the stratified space almost simultaneously with the evaporation of matter.
Since the compound (A) containing J is reacted with an active species that reacts with the J-containing compound (A), it is formed by using separate methods almost simultaneously, thereby reproducing an optical recording layer in which the metal rMJ is uniformly dispersed in the metal sulfide. can be easily created. In addition, it is possible to mass-produce an optical recording medium having an optical recording layer with stable film quality and controlled film properties.

[Example] Examples of the present invention are shown below.

(Example) Using the apparatus shown in Figure 1, the following operations were carried out:
An optical recording medium shown in FIG. 2 was prepared.

As the substrate 1, a polycarbonate substrate with a thickness of 1.2 mm and an M diameter of 200 mm was used, on which guide grooves were previously provided by an injection method. The guide grooves were formed in a spiral shape with a pitch of 1.6μ and a depth of 700.

After setting this substrate 1 into the film forming chamber 9, the evaporation source 8 (
In this example, a Knudsen cell) was heated to 1200° C. to evaporate SnS, which is a metal sulfide, which had been placed in the evaporation source 8 in advance. At about the same time, the compound (
A) (CH3)zTet is introduced into the activation chamber 10 from the gas introduction pipe 5 made of quartz glass at an inflow rate of 60 SCCM, and H2 gas is introduced into the activation chamber 10 from the gas introduction pipe 6 made of quartz glass. H radicals, which are active species generated by introducing 2003C
CM was introduced into the reaction chamber 9 at an inflow rate. In addition, activation chamber 1
0, a 300 W microphone Oat was applied to generate H radicals. Further, the pressure inside the film forming chamber 9 during film forming was adjusted to 25 Pa by the gas exhaust system 11.

When the above operation was continued for 1.5 minutes in Ml1M, Te, which is a metal derived from compound (A), was formed on the substrate 1 in SnS, which is a metal sulfide, with To: 5nS=0.
An optical recording medium having an optical recording layer with a thickness of 1000 nm dispersed at a ratio of 5:0.5' was obtained.

The characteristics of the optical recording medium created as described above are determined by the S/N
Evaluation was made in the following manner based on ratio, media noise, and storage environment characteristics.

When the obtained optical recording medium was rotated at a rotation speed of 1800 rpm, recording was performed at a recording laser power of 10 mW and a recording frequency of 4 MHz, and reproduction was performed using a reproducing laser power of 2 mW, an S/N ratio of 32d8 was obtained. In addition, this optical recording medium was placed in an environment with a temperature of 60°C and a humidity of 80%.
The increase in noise after being left for 000 hours was at an extremely low level of 4 dB, indicating that the storage environment characteristics were excellent.

Separately, 30 optical recording media having the same configuration were created according to the same method as above.゛About these optical recording media,
When the same evaluation as above was performed, all optical recording media obtained the same S/N ratio of 32 dB as above, and 100 dB.
The increase in noise after being left for 0 hours was at an extremely low level of 2 to 5 dB, and optical recording media with low noise and excellent storage environment characteristics were mass-produced with good reproducibility.

(Comparative example) An optical recording medium having the same configuration as that of the example was heated at a vacuum degree of 5
Q'Pa was prepared by the spuckling method using an electron gun, and the same evaluation as in the example was performed.

As a result, the S/N ratio was 30 dB, and the noise at this time was 2 dB higher than that of the example. Also, the temperature is 60
℃ and 80% humidity for 1000 hours, the noise increase was 15 dB, which was significantly higher than that of the example.

Separately, 30 optical recording media having the same configuration were created according to the same method as above. When these optical recording media were evaluated in the same manner as above, the S/N ratio was 25 to 3.
It was an optical recording medium with poor reproducibility, which varied within a 2 dB range. Further, the increase in noise after being left for 1000 hours was 5 to 20 dB, which was considerably higher than that on the English flow side.

[Effects of the Invention] As explained above, the method for producing an optical recording medium of the present invention makes it possible to improve the optical recording characteristics of the formed optical recording layer, and provides excellent storage environment characteristics with reduced media noise. It has become possible to mass-produce optical recording media with good reproducibility.

[Brief explanation of drawings]

FIG. 1 is an example of a schematic diagram of a manufacturing apparatus for embodying the method of the present invention, and FIG. 2 is a schematic cross-sectional view of an example of an optical recording medium produced by the method of the present invention. 5.6...Gas introduction pipe

Claims (1)

[Claims] (1) At least one compound represented by the following general formula (A), which is a raw material for forming the optical recording layer, is placed in the film forming space for forming the optical recording layer on the substrate, and an active substance that chemically reacts with the compound By introducing the seeds and evaporating the metal sulfide, which is another raw material for forming the optical recording layer, in the film forming space almost simultaneously, the general formula (A) is introduced into the metal sulfide onto the substrate. A method for producing an optical recording medium, comprising forming an optical recording layer in which a metal M derived from a compound of R_nM_m...(A) (However, m is a positive integer that is equal to or an integral multiple of the valence of R, n is a positive integer that is equal to or an integral multiple of the valence of M,
M represents a metal element, and R represents hydrogen, halogen, or a hydrocarbon group. )