JPS6232087A - Preparation of optical recording medium - Google Patents

Abstract

PURPOSE:To enable the mass production of an optical recording medium excellent in optical recording characteristics with good reproducibility, by reacting a specific compound containing a desired metal with an active seed in a film forming space almost simultaneously with the evaporation of metal fluoride in the film forming space. CONSTITUTION:A compound, which contains a metal M coming to the component of a formed optical recording layer, represented by RnMn (wherein m and n are respectively equal to the valenices of R and M or positive integers being integer-times said valencies, M is a metal element and R is hydrogen, halogen or a hydrocarbon group) introduced into a film forming space, the exciting seed thereof and an active seed separately introduced apart form said seed chemically perform interaction. Thus formed desired metal M is accumulated on a substrate 7 along with the vapor of metal fluoride almost simultaneously generated in an evaporation source 8. As a result, a desired optical recording layer 4 wherein the metal M is uniformly dispersed in metal fluoride is easily formed on the substrate 7.

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 bismuth Bi 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.

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 tends to cause noise when recording is reproduced, and a stable reproduced signal cannot be obtained, that is, it is difficult to achieve high-density recording.

Film forming methods such as vacuum evaporation, sputtering, ion blating, plasma CVD, thermal CVD, and photoCVD have been tried to form such an optical recording layer. law is widely used,
It has also been corporatized.

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, which has been widely used, has the following problems.

In other words, in the sputtering method, there are many formation parameters (e.g., substrate, sputtering pressure, high frequency power, Kuget-to-substrate distance, pumping speed, substrate rotation speed, etc.). This resulted in an unstable state and often caused a significant negative shadow on the formed optical recording layer.

In addition, device-specific parameters had to be selected for each device.In addition, there were 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. There was also the problem that the substrate temperature 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.
! Another object of the present invention is to easily mass-produce optical recording media that can improve the storage characteristics of optical recording media, and in particular have low media noise and excellent storage environment characteristics. The purpose of the present invention is to provide a method for manufacturing an optical recording medium that can be manufactured by using the following methods.

[Means for Solving the Problems] The present invention achieves the above object by applying the following general formula (A) as a raw material for forming an optical recording layer to 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 fluoride, 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 fluoride 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) (where m is a positive integer equal to or an integral multiple of the valence of day, n(, a positive integer equal to or an integral multiple of the valence of tM, M is a metal element, Embodiments of the Invention A typical example of an optical recording medium formed by the method of the 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) (that is, "M" of the compound of the formula (A)) dispersed in a metal fluoride 2.

Specifically, gold 513 includes Te, Bi, Sn,
In, Pb, Cu, Ti, Zr, Ta, ＾u,
Examples include P't, Se, Zn, etc., and these gold 1
One or more of the above is B1F2, M9F2, PbF2, LiF
, A9F, CaF2, CrF2, CrF3, carbon fluoride, etc., are dispersed in a metal fluoride 2 to form an optical recording layer 4.

For example, ^r-Ne laser,
When irradiated with recording light of various wavelengths including laser light from a semiconductor laser, the optical properties (e.g., reflectance, transmittance, refractive index, etc.) of the optical recording layer 4 made of metal fluoride 2 and gold FA3 change. Recording is performed by changing the recording light and creating an optical difference between the area irradiated with the recording light and the area not irradiated with the recording light. Reproduction of recording is performed by irradiating a recording portion with a reproduction light such as the laser beam described above and detecting an optical difference in the optical recording layer.

In an optical recording medium having such an optical recording layer, since recording and reproduction do not depend on the formation of recording bits, high-quality original recording is possible. Moreover, since the metal fluoride 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 density, etc. Also, an adhesive layer, an antireflection layer, or a protective layer may be provided on the substrate 1. A variety of functional layers widely known in this type of technology, such as a 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 cause a chemical interaction 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 gold RrM derived from compound (A) into a state where it can be dispersed in the optical recording layer.Therefore, as an "active species", it constitutes the optical recording layer to be formed. It may or may not contain such ingredients.

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 molecular collisions with the above-mentioned active species in the space where the substrate on which the film is to be formed and cause a chemical reaction, resulting in the formation of metal rMJ, which is a component of the optical recording layer formed on the substrate. It is more desirable to select one that spontaneously generates chemical species that contribute to its formation. 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 the compound (
^).

In the present invention, compounds in which the compound (A) is in the above excited state are hereinafter 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, D, 8i, S
n, In, Pb, Cu, Ti%Zr%Ta,
One or more of Au, Pt, Se, Zn, etc. is used.

rRJ includes monovalent, divalent, and trivalent hydrocarbon groups derived from M-chain and side-chain saturated hydrocarbons and unsaturated hydrocarbons, or saturated or unsaturated monocyclic and polycyclic Mention may be made of monovalent, divalent and trivalent hydrocarbon groups derived from hydrocarbons.

Unsaturated hydrocarbon groups include not only a single type of carbon-carbon bond but also those having at least two types of bonds among - double bonds, double bonds, and triple bonds. 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,
Preferred examples include alkynyl groups, alkylidene groups, alkylidine groups, alkynyl groups, alkylidine groups, alkylidine groups, alkynyl groups, etc. In particular, the number of carbon atoms is preferably 1 to 10, more preferably preferably has 1 to 7 carbon atoms, most preferably 1 to 5 carbon atoms.

In the present invention, the above-listed rRJ and "M ”, the combination of rRJ and “M” is selected as desired.

In the present invention, a specific compound that is effectively used as compound (A) is Z nMe 3.2nEt3
, Me2Se, Me2Te, Et2Se, Et
2Te, SeL, 5eXn, 5eXb, TeXb,
H2S+3゜8 iX3.5nX4, PbEtn, Cu
X3, TiX*, 2rL, TaX5, (PtX2)2
(Co)3, H2T6, etc. can be mentioned. In the above, X is halogen (F, CI, Sr, I)
, Me represents a methyl group, and Et represents an ethyl group.

In the present invention, metal fluorides that are effectively used as constituent components of the optical recording layer include B1F2,
M9F2, PbF2, LiF, AgF, CaF2
, CrF2, CrF3, fluorocarbon, and the like.

One or more of these metal fluorides is appropriately selected and evaporated in the film forming space to form an optical recording layer together with the above-mentioned gold arM.

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 fluoride is evaporated almost simultaneously within the film forming space. That is, the metal fluoride evaporated in the film formation space is deposited on the substrate, and the compound (
Metal "M" produced by the reaction between A) and an active species
By substantially simultaneous deposition of the two on the substrate, an optical recording layer is formed in which the metal "M" derived from the compound (A) is dispersed in the metal fluoride.

Compounds introduced into the film forming space by this method (^)
As active species, chemical reactions occur due to mutual collisions at the molecular level, and compound (A) is formed in the optical recording layer.
If a metal capable of producing gold JirMJ derived from . However, if the above chemical reactivity is poor due to the selection of the compound (A) and the active species,
Alternatively, in order to more effectively carry out the chemical reaction and efficiently generate metal rMJ in the optical recording layer, reaction promoting energy acting on the compound (A) and/or the active species in the film forming space, For example, activation energy similar to that used in the activation space described below may be used.

Furthermore, before introducing the compound (A) into the film forming space, excitation energy may be applied to the compound (A) in another activation space in order to bring the compound (^) into the above-mentioned excited state.

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 be active when introduced into the film forming space, they are introduced in the following manner. Activation energy such as heat, light, or discharge is applied in different activation spaces to generate active species, and the active species are introduced into the film forming space.

Introduced into the activation space, the activation f! The raw material for generating is preferably a gaseous or easily vaporizable substance that generates hydrogen radicals, and specific examples include H2,02, HD, etc.
, Ar and other rare gases can also be mentioned.

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,
These activation energies can be applied to the active species generating substance alone in the activation space, or can be applied to two or more types of activation energy. It may also 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 is:
It can be determined as desired depending on the film forming conditions, the type of compound (A) and active species, the desired characteristics of the optical recording layer, etc., but it is preferably 1000:1 to 1:1 (introduction flow rate ratio) or an appropriate value, and more The ratio is preferably 500:1 to 1:5.

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
×103Pa, more preferably 5XIO-2~IX
It is desirable to set the pressure to 103 Pa, most preferably from 1×10 −1 to 5×10 2 Pa.

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 chemical reaction with compound (A) in a chain reaction, a so-called initiator (initiator) is used.
Since it is sufficient to minimize its function as a teater, the amount introduced into the film-forming space should be such that a chemical reaction can occur efficiently in a chain reaction.

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 to be used should be selected in such a way that an optical recording layer having the desired characteristics can be effectively obtained, taking production efficiency into account as well, and should be appropriately selected in relation to other film-forming conditions. Active species with a long lifespan are appropriately selected and used.
! The active species used in the present invention has a lifespan of 1F! : An active species having a lifespan appropriately selected in view of the above is selected as desired from within the compatible range of chemical affinity with the compound (A) to be specifically used, but preferably - Its lifespan is 1×1 under the environment within the scope of the present invention.
It is desirable that the time is 0'4 seconds or more, more preferably 1X10' seconds or more, most preferably 1X10-2 seconds or more.

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 fluoride forming the optical recording layer together with the metal "M" described above is evaporated in the film-forming space almost simultaneously when the compound (A) and the active species are introduced into the film-forming space. .

The evaporation of the metal fluoride is achieved by installing an evaporation source such as a Knudsen cell in the film formation space, so that the evaporation rate of gold and fluoride is zero at the production rate of the optical recording layer composed of metal rMJ and metal fluoride. It is best to do this at a rate of .01 to 1 scale/minute.

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

This device mainly consists of a film forming chamber 9 (corresponding to a film forming space), an evaporation source 8 installed in the chamber 9, and an activation chamber 10 (corresponding to an activation space). ing. 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 almost simultaneously when forming the optical recording layer in the film forming space, and contains metal rMJt which becomes a component of the formed optical recording layer. Excitation of the compound (A) and the compound (A)! 1(A). Desired metal “M” made of Koushi
is deposited on the substrate 7 together with the metal fluoride vapor used in the evaporation source 8. As a result, a desired optical recording layer 4 in which metal "M" is dispersed in metal fluoride is easily formed on a desired substrate.

In the method of the present invention, an optical recording layer is formed by evaporating a metal fluoride, which is one component of the optical recording layer, in a film-forming space, and a metal rMJ, which is another component, is added to the metal fluoride. The metal rMJ is formed by a separate method of reacting the MJ-containing compound (A), which is introduced into the film formation space almost simultaneously with the evaporation of the metal rMJ, with an active species that reacts with it. It is possible to create an optical recording layer that is uniformly dispersed in fluoride with good reproducibility.In addition, it is possible to mass-produce optical recording media that have an optical recording layer with stable film quality and controlled film properties. It can be easily manufactured.

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

〔Example〕

Using the apparatus 1 shown in FIG. 1, the optical recording medium shown in FIG. 2 was produced by the following operations.

As the base 1, a polycarbonate substrate having a thickness L2 mm and a diameter 200 mm was used, on which guide grooves were previously provided by an injection method. The guide groove has a pitch of 1.6μ and a depth of 7
It was formed into a spiral shape by 00 people.

After setting the substrate 1r8 in the film forming chamber 9, the evaporation source 8 (
In this example, a Knudsen cell) was heated to 720° C. to evaporate BiFp, a metal fluoride, which had been placed in the evaporation source 8 in advance. At almost the same time, compound (A) (CH3)2Te is activated from the quartz glass gas introduction tube 5 at an inflow rate of 603 CCM! In addition to introducing it into the sacrificial room 10, H? H radicals @200 are active species generated by introducing gas into the activation chamber 10 from the quartz glass gas introduction pipe 6.
SCCM was introduced into the reaction chamber 9 at an inflow rate. In the activation chamber 10, 300 W microwaves were applied to generate H radicals. Further, the pressure in 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, Te, which is a metal derived from compound (A), was formed on the substrate 1 in BiFz, which is a metal fluoride, and Te: BiF2=0
．． An optical recording medium having a film thickness of 1000 layers dispersed at a ratio of 6+0.4 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 2 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. When these optical recording media were evaluated in the same way as above, all optical recording media obtained the same S/N ratio of 32 dB as above, and 1000 dB.
The increase in noise after standing for a period of time was at an extremely low level of 1 to 3 dB, and optical recording media with low noise and excellent storage environment characteristics were being mass-produced with good reproducibility.

[Comparative example]

An optical recording medium having a configuration similar to that of the example was prepared under a vacuum degree of 5 x t.
o'' Pa by a sputtering method using an electron gun, and the same evaluation Ii5 as in 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
The increase in noise after being left in an environment of 80% humidity and I Ode for 1000 hours was significantly greater 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 27 to 3.
It was an optical recording medium with poor reproducibility, which varied within a 1 dB range. Further, the increase in noise of the bonds left for 1000 hours was 3 to 10d8, which was considerably higher than that of the example.

[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. 1.7--Substrate 2--Metal fluoride 3--
Metal 4--One optical recording layer 5.6--Gas introduction tube

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 fluoride, 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 fluoride 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. )