JP2941822B2 - Optical memory medium - Google Patents

Abstract

PURPOSE:To increase contrast, to eliminate a decrease in C/N, to extend the life of recording bits, and to improve stability by using a thin film in which in which fine metal particles are dispersed in hydrocarbon polymer. CONSTITUTION:A thin film formed on a board of an optical memory medium is composed by dispersing fine metal particles in hydrocarbon polymer. The film is formed by reactive sputtering, reactive depositing, plasma CVD, optical CVD, etc. When the medium is composed of the fine metal particles, the resolution of recording bits is high. The film which contains metal oxide is formed with recording bits by radiating it with an electron beam, and then heat treated to erase the recording to be again newly used. The recording bit positions formed by a laser are formed in a flatly smooth protrusion shape having 1,500-4,500Angstrom of height, and have large reflectivity change before and after the recording. Accordingly, a high contrast is obtained between the recording part and a nonrecorded part.

Description

The present invention relates to an optical memory device, an optical disk, an optical card,
The present invention relates to an optical memory medium that can be used for documents and image files.

[Prior Art] Conventionally, as an optical memory medium of a heat mode (melting and evaporating type), a metal film of Al, Cr, Cu, Au, Ni, Ti, Bi, etc. (Nikkan Kogyo Shimbun: April 14, 1987) Version) or T
e, Te compound and other chalcogenide films [M. Terao, et al:
J.Appl.Phys. 50, 6881 (1979) ], and the like are known. However, since the metal film has a poor absorption efficiency of laser light, a strong laser light and time (100 mW × 1 μse
c), the recording speed at high speed is insufficient in sensitivity, and the noise at the time of reproduction is liable to increase due to the swelling around the pits generated at the time of bit formation. Further, the chalcogenide vapor-deposited film has a disadvantage that it is deteriorated by heat, humidity and the like.

Conventionally, as a phase transition type optical memory, chalcogen films such as Te and Te compounds [SROvshinsky; Appl. Phy's. Lett.
18 , 254 (1971)], but has the disadvantage that the change in reflectivity during recording is as low as about 10% and the contrast is small.

As the bubble mode recording, In-CH ₄ -O ₂ system sputtered film [Takeoka, Ozawa, Okao, Yasuda, optical memory Symposium '85, 39 (1985)] are known, component oxide And In or In ₂ O _{3 in the} film
And organic components exist separately as clusters, and thus have problems in long-term stability and stability under high humidity. Further, there is a drawback that the contrast of the bubble is small because the protrusion of the bubble as the recording portion is as small as 1000 °.

[Problems to be Solved by the Invention] The present invention has been made in view of such a situation,
It is an object of the present invention to provide an optical memory medium having a large C / N, a long life of a recording bit, good stability, no pollution, and which can be manufactured at low cost.

[Means for Solving the Problems] The present inventor has been studying in order to solve the above problems, but metal fine particles are dispersed in a hydrocarbon polymer formed by reactive sputtering or the like. It has been found that the use of a thin film is effective, and the present invention has been achieved.

That is, the present invention provides an optical memory medium having a thin film provided on a substrate, wherein the thin film is formed by reactive sputtering, reactive deposition, plasma CVD or photo CVD, and fine metal particles are dispersed in a hydrocarbon polymer. An optical memory medium characterized by being constituted.

In the present invention, the film can be formed by reactive sputtering, reactive deposition, plasma CVD, optical CVD, or the like.
The film thickness is not particularly limited, but is desirably in the range of 100 to 10,000, preferably 200 to 5,000.
The composition of the film is 5 to 95% carbon, preferably 20 to 80%.
%, 5 to 95% of metal fine particles, preferably 20 to 80%
% Is desirable.

Examples of the metal fine particles in the present invention include:
Examples include iron, nickel, cobalt, copper, and titanium. Further, as the metal fine particles, metal oxide fine particles are also effective. In particular, in the case of CuO and Cu ₂ O, the copper oxide in the hydrocarbon polymer constituting the film is reduced by electron beam irradiation to become metallic copper, and at that time, the light reflectance of the film is significantly increased, In addition, when this is subjected to a heat treatment, it returns to a state before irradiation, and this can be used to provide a memory in which pits can be formed by an electron beam. In this case, an electron beam of 3000 to 4000 μc / cm ² can be used. That is, the transmittance of the film is 400-700 nm
By irradiating this film with an electron beam, the copper oxide is reduced and changed to metallic copper,
As a result, the transmittance of the membrane is reduced to a few percent. If the film after recording is heat-treated in the air, it returns to the film before recording. The condition of this heat treatment is to convert copper to a copper oxide, and it is preferable to use a copper lower oxide. At 200 ° C., the heat treatment can be performed in less than 5 minutes. When the temperature is lower than 200 ° C., it may be 5 minutes or more. By applying this principle, it is possible to form and erase bits in a film. As described above, in the case of being composed of copper and an oxide such as CuO and Cu ₂ O, the ratio is preferably such that a sufficient contrast by electron beam irradiation can be obtained, and the oxide is contained in the metal at 10% or more. Good.

In the present invention, the size of the fine particles of iron, cobalt, nickel and titanium is desirably 1000 ° or less, preferably 300 ° or less. The size of the copper microparticles is desirably in the range of 1000 ° or less, preferably 200 ° or less.

The material of the substrate on which the memory material of the present invention is formed is not particularly limited, and may be various plastics (for example, polymethyl methacrylate, polycarbonate, and the like), glass, ceramic, metal, and the like. Further, a preformat of an address signal or the like and a pregroove of a guide groove may be formed on the surface of the substrate. The shape of the substrate may be an arbitrary one such as a tape, a disk, a drum, and a belt depending on the use application.

The optical memory medium of the present invention basically comprises a substrate and the above-mentioned memory material, but may further have another layer (for example, a protective layer) according to the purpose. Also, an air sandwich structure can be used to prevent dust and scratches.

Next, a method for manufacturing the optical memory medium of the present invention will be specifically described.

An optimal method according to the present invention is to apply an organometallic compound or an organometallic complex containing at least a metal as one of the starting materials to a plasma CVD method on a substrate set in a vacuum reactor.
This is a method of forming a film by a method. Among them, the plasma CVD method using glow discharge is more preferable. As an example of a starting material, for example, iron (III)
Iron carboxylate such as acetylacetonate, iron acetate, iron naphthenate, iron benzoate and fluorinated iron carboxylate and ferrocene, or tyrone, ethylenediamine, 2,2'-dipyridine, 1,10-phenanthroline, dithiol, oxine , Thioxine, 3-mercapto-p
-An iron complex having a chelating agent such as cresol is used. As the cobalt compound, cobalt (II)
Cobalt carboxylate such as acetylacetonate, cobalt (III) acetylacetonate, cobalt acetate, cobalt naphthenate, cobalt benzoate or fluorinated cobalt carboxylate and cobalt sen, or tyrone, ethylenediamine, 2,2'-dipyridine, 1,10-phenanthroline, dithiol, oxine, thioxine,
A cobalt complex having a chelating agent such as 3-mercapto-p-cresol is used.

Examples of the nickel compound include nickel carboxylate such as nickel acetylacetonate (NiAA), nickel oxalate, nickel acetate, and nickel formate; fluorinated nickel carboxylate; dimethylglyoxime; benzyldioxime; cyclohexane-1,2- Dionedioxime, tiron, ethylenediamine, 2,2'-dipyridine, 1,10-phenanthroline, dithiol, oxine,
A nickel complex having one or two chelating reagents such as thioxine and 3-mercapto-p-cresol is used.

Examples of the copper compound include copper carboxylate such as copper acetylacetonate (CuAA), copper oxalate, copper acetate and copper formate, and fluorinated copper carboxylate and tyrone, ethylenediamine, 2,2′-dipyridine, 1,10 One to two chelating reagents such as phenanthroline, dithiol, oxine, thioxine, 3-mercapto-p-cresol;
A copper complex having one is used.

Examples of the titanium compound include diisopropoxytitanium bis (acetylacetonate), bis (acetylacetonato) titanium oxide, titanium tetramethoxide, titanium tetraethoxide, and titanium tetra-oxide.
n-Propoxide, titanium tetraisopropoxide, titanium tetrabutoxide, titanium tetraisobutoxide and the like are used.

When representative production conditions are shown, for example, He, Ne, Ar, N ₂ or the like is used as a carrier gas, and, as necessary, as a reaction gas, for example, O ₂ , CO, CO ₂ , CH ₄ , C ₂ H ₄ etc. are used.

The glow discharge device may be a DC glow discharge device or a capacitively or inductively coupled AC glow discharge device. The reaction gas pressure is 0.001 to several Torr, preferably 0.002 to
2 Torr. The power is 1 to 300 W, preferably 5 to 100 W, and the discharge time is 1 to 200 minutes, preferably 2 to 180 minutes.
The substrate temperature is 0 to 350 ° C, preferably 20 to 200 ° C.

Examples for producing the memory medium of the present invention will be described below.

Example 1 A plasma CVD apparatus shown in FIG. 1 was used as a manufacturing apparatus.

In FIG. 1, 1 is an RF power source, 2 is a thermocouple, 3 is an electrode, 4 is a substrate, 5 is a starting material, 6 is a heater, 7 is a counter electrode, 8 is a vacuum gauge, 9 is an oil diffusion pump, 10 is An oil rotary pump 11 is a heater control unit.

FIG. 2 shows a plasma power of 70 W at a CuAA partial pressure of 0.004 Torr and
The relationship between the film forming time and the film thickness when forming a film on a glass plate at 30 W is shown. The film thickness increases linearly with the film forming time, and the higher the plasma power, the lower the film forming speed. Until the film formation time of 20 minutes, the induction period in which the partial pressure of CuAA reaches 0.004 Torr.

Figures 3 to 5 show CuAA and plasma CVD at various film thicknesses
The reflectance, absorption and transmittance at 800 nm of the thin film are shown. The film thickness can be set to an arbitrary thickness by changing the film formation time. It can be seen that the reflectance, absorptance, and transmittance can be arbitrarily controlled between 0 and 50% depending on the film thickness.

6 to 9 show the relationship between the plasma power and the partial pressure of CuAA and the film thickness, the reflectance, the absorptivity, and the transmittance when the film is formed for 60 minutes. The reflectivity of the film increases when made with lower CuAA partial pressure, or higher plasma power,
It can be seen that the absorption rate has a maximum value at a certain plasma power.

From the above results, a thin film having arbitrary reflectance and absorptance can be manufactured by setting the thin film manufacturing conditions.

From the IR and XPS spectra, it was found that these films were mainly composed of metallic copper and a hydrocarbon polymer CH _{2 n} . Oxygen was present at 0.5 atomic%. TEM
According to observations, these films were found to contain 10-
It was confirmed that the particles were coated with a certain degree of hydrocarbon polymer.

Next, the optical writing performance of the film manufactured as described above was evaluated under the following conditions.

Disc substrate: Polycarbonate Disc rotation speed: 900 rpm Beam linear velocity: 6 m / s Beam wavelength: 830 nm Beam diameter: 1 μm φ Reflectance 50%, absorption 40%, 500 mm thick CuAA plasma C
When a VD thin film was used as a recording medium, recording could be written with any beam power of 3, 5, 7, and 9 mW, and a change in reflectance was clearly observed with an optical microscope. SE
By M observation, ridge shapes having heights of 2000, 3500, 3500, and 4500 ° were observed at recordings of beam powers of 3, 5, 7, and 9 mW, respectively. This bulge is generated in the recording part by evaporating a relatively low-molecular hydrocarbon polymer among metal-coated hydrocarbon polymers by laser energy. Regarding the shape of the recording portion, recording at 7 mW was the best spherical surface. Bits were observed on the surface when recording at 3.5 mW, and some pinholes were observed on the surface when recording at 9 mW.

CuAA plasma with reflectivity of 20%, absorptance of 60% and film thickness of 1200mm
When a CVD thin film was used as a recording medium, recording was not possible at a beam power of 3 mW, and recording was possible at a beam power of 5, 7, and 9 mW, and a change in reflectance was clearly observed with an optical microscope. Observing the recording section by SEM, when the beam power is 5 or 7 mW, it is about 1500Å
A raised shape having a height of Å was observed. No pinhole on the raised surface was observed at any beam power.

Example 2 As starting material A film was produced in the same manner as in Example 1 except that was used. This was found to have the same effect as the film obtained in Example 1.

Example 3 A film was produced in the same manner as in Example 1 except that copper oxalate was used as a starting material. This was found to have the same effect as the film obtained in Example 1.

Example 4 A film was produced in the same manner as in Example 1 except that copper acetate was used as a starting material. This was found to have the same effect as the film obtained in Example 1.

Example 5 A film was produced in the same manner as in Example 1 except that copper formate was used as a starting material. This was found to have the same effect as the film obtained in Example 1.

Copper ethylenediamine bis acetylacetonate as Example 6 The starting material _{[Cu (C 12 H 18 N} 2 O 2)] Example except for using 1
A film was produced in the same manner as described above. This was found to have the same effect as the film obtained in Example 1.

Example 7 A film was produced in the same manner as in Example 1 except that copper oxinate [Cu (C ₉ H ₆ NO) ₂ ] was used as a starting material. This was found to have the same effect as the film obtained in Example 1.

Example 8 In this example, a film was formed using nickel acetylacetonate as a starting material by a plasma CVD method under the following manufacturing conditions.

[Production conditions] Production equipment: Plasma CVD apparatus shown in Fig. 1 Starting material: Nickel acetylacetonate Substrate: Slide glass, Si wafer, polyethylene terephthalate, polycarbonate Substrate temperature: 70 ° C Reaction stress: 5.0 × 10 ^-3 Torr Heater temperature … 65 ° C High frequency power… 100W, 13.56MHz Discharge time… 60 minutes The film obtained has a reflectance of 55% and an absorption of 4 at a wavelength of 800nm
The film thickness was 700 mm at 5%. According to IR and XPS spectra, this film is mainly composed of metallic nickel and hydrocarbon polymers.
It was found that it was composed of CH _{2 n} . TEM observation showed that this film was coated with nickel fine particles of about 200 mm by a hydrocarbon polymer.

Next, the optical writing performance of the film manufactured as described above was evaluated under the following conditions.

Disk substrate: Polycarbonate Disk rotation speed: 900 rpm Beam linear velocity: 6 m / s Beam wavelength: 830 nm Beam diameter: 1 μm φ Beam power: 5 mW Reflection change was clearly recognized by an optical microscope in a portion written by a laser. The recording part is 300 by SEM observation
It formed a smooth spherical bump with a height of 0 °. Also, the non-recording portion was extremely smooth.

Example 9 A membrane was produced in the same manner as in Example 8, except that a dimethylglyoxime-nickel complex salt was used as a starting material. The same effect as that of the film obtained in Example 8 was recognized.

Example 10 A film was produced in the same manner as in Example 8, except that the plasma power was 50 W as the thin film production conditions. The resulting film has a wavelength
At 800 nm, the reflectance was 40%, the absorptance was 60%, and the film thickness was 1000 °, and the same effects as those of the film obtained in Example 8 were recognized.

Example 11 A film was produced in the same manner as in Example 8, except that the thin film was produced at a plasma power of 30 W. The resulting film has a wavelength
At 800 nm, the reflectance was 20%, the absorptance was 80%, and the film thickness was 1500 °, and the same effect as the film obtained in Example 8 was recognized.

Example 12 In this example, a film was formed by using a cobalt (II) acetylacetonate as a starting material by a plasma CVD method under the following manufacturing conditions. The manufacturing apparatus shown in FIG. 1 was used.

[Preparation conditions] Substrate: slide glass, silicon wafer, polyethylene terephthalate, polycarbonate Substrate temperature: 25 ° C Partial pressure of cobalt (II) acetylacetonate: 1.0 × 1
Pressure at the time of 0 ^-3 Torr reaction: 2.0 × 10 ^-3 Torr High frequency power: 90 W, 13.56 MHz Discharge time: 120 minutes As shown in FIG. 10, the obtained film has a reflectance of 32% and an absorption of 28 at a wavelength of 800 nm as shown in FIG. % And the film thickness was 440 °. From the IR and XPS spectra, it was found that this film was mainly composed of metallic cobalt and the hydrocarbon polymer CH _{2 n} . Also, from TEM observation, this film was about 200 mm thick.
It was recognized that the cobalt fine particles formed a structure covered with an organic layer.

Next, optical writing of the film manufactured as described above was evaluated under the following conditions.

Disk substrate: Polycarbonate Disk rotation speed: 900 rpm Beam linear velocity: 6 m / s Beam wavelength: 830 nm Beam diameter: 1 μm φ Beam power: 5 mW The change in reflectivity was clearly recognized by the optical microscope in the portion written by the laser. Recorded area is 1 by SEM observation
It formed a smooth spherical raised shape with a height of about 500 mm. Also, the non-recording portion was extremely smooth.

Example 13 In this example, a film was formed using cobalt (III) acetylacetonate as a starting material by a plasma CVD method under the following manufacturing conditions.

[Manufacturing conditions] Manufacturing apparatus: Plasma CVD apparatus shown in FIG. 1 Substrate: Slide glass, silicon wafer, polyethylene terephthalate, polycarbonate Substrate temperature: 25 ° C. Partial pressure of cobalt (III) acetylacetonate: 1.0 ×
10 ^-3 ~2.0 × 10 ^-3 Torr pressure during reaction ^{... 2.0 × 10 -3 Torr~3.0 × 10} -3 Torr RF power ... 90W, 13.56 MHz discharge time ... 180 minutes resulting film are shown in FIG. 11 Thus, at a wavelength of 800 nm, the reflectance was 23%, the absorption was 56%, and the film thickness was 1,300 mm. From the IR and XPS spectra, it was found that this film was mainly composed of metallic cobalt and the hydrocarbon polymer CH _{2 n} . Also, from TEM observation, this film was about 150 mm thick.
It was recognized that the cobalt fine particles formed a structure covered with an organic layer.

Next, optical writing of the film manufactured as described above was performed in Example 12.
The evaluation was performed under the same conditions as described above.

The change in the reflectance of the portion written by the laser was clearly observed by an optical microscope. The recording part is 3 by SEM observation
It formed a smooth spherical raised shape with a height of about 000 mm. Also, the non-recording portion was extremely smooth.

Example 14 In this example, a film was formed by a plasma CVD method using cobalt (II) acetylacetonate as a starting material under the following manufacturing conditions.

[Manufacturing conditions] Manufacturing apparatus: Plasma CVD apparatus shown in FIG. 1 Substrate: Slide glass, silicon wafer, polyethylene terephthalate, polycarbonate Substrate temperature: 25 ° C. Partial pressure of cobalt (II) acetylacetonate: 2.0 × 1
0 ^-3 Reaction pressure: 3.0 × 10 ^-3 Torr High frequency power: 90 W, 13.56 MHz Discharge time: 70 minutes The obtained film has a reflectance of 27% and an absorption of 27% at a wavelength of 800 nm as shown in FIG. And the film thickness was 850 mm. From the IR and XPS spectra, it was found that this film was mainly composed of metallic cobalt and the hydrocarbon polymer CH _{2 n} . Also, from TEM observation, this film was found to be 50-150
It was confirmed that the cobalt fine particles of Å formed a structure covered with the organic layer.

Next, optical writing of the film manufactured as described above was performed in Example 12.
The evaluation was performed under the same conditions as described above.

The change in the reflectance of the portion written by the laser was clearly observed by an optical microscope. The recording part is 2 by SEM observation
It formed a smooth spherical raised shape with a height of about 000 mm. Also, the non-recording portion was extremely smooth.

Example 15 In this example, a film was formed by plasma CVD using bis (acetylacetonato) titanium oxide as a starting material under the following manufacturing conditions. The manufacturing apparatus shown in FIG. 1 was used.

[Preparation conditions] Substrate: slide glass, silicon wafer, polyethylene terephthalate, polycarbonate Substrate temperature: 90 ° C. Partial pressure of bis (acetylacetonate) titanium oxide: 1.0 × 10 ⁻³ Torr Pressure during reaction: 2.0 × 10 ⁻³ Torr High frequency power: 100 W, 13.56 MHz Discharge time: 120 minutes The obtained film had a reflectance of 45%, an absorptance of 55% and a film thickness of 400 mm at a wavelength of 800 nm. From the IR and XPS spectra, this film is mainly composed of titanium metal and hydrocarbon polymer CH _2
n . Also TE
From M observation, it was confirmed that this film formed a structure in which titanium particles of about 200 ° were covered with an organic layer.

Next, optical writing of the film manufactured as described above was evaluated under the following conditions.

Disk substrate: Polycarbonate Disk rotation speed: 900 rpm Beam linear velocity: 6 m / s Beam wavelength: 830 nm Beam diameter: 1 μm Beam power: 5 mW The change in reflectance was clearly recognized by the optical microscope in the portion written by the laser. According to SEM observation, the recording part had a smooth spherical raised shape with a height of about 1500 mm. Also, the non-recording portion was extremely smooth.

Example 16 In this example, titanium tetraisopropoxide was used as a starting material, and a film was formed by a plasma CVD method under the following manufacturing conditions. The titanium tetraisopropoxide was supplied from outside the reactor through a mass flow controller.

[Manufacturing conditions] Manufacturing apparatus: Plasma CVD apparatus shown in FIG. 1 without heater Substrate: Slide glass, silicon wafer, polyethylene terephthalate, polycarbonate Substrate temperature: 25 ° C. Titanium tetraisopropoxide partial pressure: 1.0 × 10
Pressure during ^-3 Torr reaction: 2.0 × 10 ^-3 Torr High frequency power: 100 W, 13.56 MHz Discharge time: 60 minutes The obtained film has a reflectance of 35%, an absorption of 65% and a film pressure of 1100Å at a wavelength of 800 nm. Was. From the IR and XPS spectra, this film was mainly composed of titanium metal and hydrocarbon polymer CH.
It was found to be composed by _{2 n.} Also, T
Observation by EM showed that this film formed a structure in which titanium particles of about 150 ° were covered with an organic layer.

Next, optical writing of the film prepared as described above was performed in Example 15.
This was performed under the same conditions as described above.

The change in the reflectance of the portion written by the laser was clearly observed by an optical microscope. According to SEM observation, the recording part had a smooth spherical raised shape with a height of about 3000 mm. The non-recording portion was also extremely smooth.

Example 17 A plasma CVD apparatus shown in FIG. 1 was used as a manufacturing apparatus.

In FIG. 1, 1 is an RF power source, 2 is a thermocouple, 3 is an electrode, 4 is a substrate, 5 is a starting material, 6 is a heater, 7 is a counter electrode, 8 is a vacuum gauge, 9 is an oil diffusion pump, 10 is An oil rotary pump 11 is a heater control unit.

[Preparation conditions] Substrate: slide glass, silicon wafer, polyethylene terephthalate, polycarbonate Substrate temperature: 90 ° C. Partial pressure of iron acetylacetonate: 1.0 × 10 ⁻³ Torr Ar flow rate: 10.0 SCCM Reaction pressure: 5.0 × 10 ⁻² Torr High frequency power: 100 W, 13.56 MHz Discharge time: 120 minutes The obtained film had a reflectance of 35%, an absorptance of 65%, and a film thickness of 800 mm at a wavelength of 800 nm. From the IR and XPS spectra, this film was mainly composed of metallic iron and a hydrocarbon polymer CH _{2 n.}
Turned out to be composed by. From TEM observation, it was confirmed that this film had a structure in which iron particles of about 100 mm were dispersed in the organic layer.

Next, optical writing of the film manufactured as described above was evaluated under the following conditions.

Disk substrate: polycarbonate Disk rotation speed: 900 rpm Beam linear velocity: 6 m / s Beam wavelength: 830 nm Beam system: 1 μm Beam power: 5 mW The change in reflectivity was clearly recognized by the optical microscope in the portion written by the laser. According to SEM observation, the recording part had a smooth spherical raised shape with a height of about 1500 mm. Also, the non-recording portion was extremely smooth.

Example 18 In this example, ferrocene was used as a starting material and plasma
A film was formed by a CVD method according to the following manufacturing conditions.

[Production conditions] Production equipment: Plasma CVD equipment shown in Fig. 1 Substrate: Slide glass, silicon wafer, polyethylene terephthalate, polycarbonate Substrate temperature: 50 ° C Ferrocene partial pressure: 2.0 × 10 ^-3 Torr Ar flow rate: 10.0 SCCM reaction Pressure: 5.0 × 10 ^-2 Torr High-frequency power: 70 W, 13.56 MHz Film-forming time: 60 minutes The obtained film had a reflectance of 30%, an absorptance of 70%, and a film thickness of 1100 mm at a wavelength of 800 nm. From the IR and XPS spectra, this film was mainly composed of metallic iron and hydrocarbon polymer CH _2
n . Also, TEM
From observation, it was confirmed that this film formed a structure in which iron particles of about 150 ° were dispersed in the organic layer.

Next, optical writing of the film manufactured as described above was performed in Example 17.
The procedure was performed under the same conditions as described above.

The change in the reflectance of the portion written by the laser was clearly observed by an optical microscope. According to SEM observation, the recording part had a smooth spherical raised shape with a height of about 3000 mm. Also, the non-recording portion was extremely smooth.

Example 19 In this example, a film was formed by a plasma CVD method using copper acetylacetonate as a starting material under the following manufacturing conditions.

[Manufacturing conditions] Manufacturing apparatus: plasma CVD apparatus shown in FIG. 13 1: plasma reactor, 2, 3, rf electrode, 4, vacuum pump, 5, rf power supply, 6, 7: substrate temperature control apparatus, 8: matching box 9: vacuum gauge, 10 ... trap, s _1, s ₂ ... substrate.

Starting material: Copper acetylacetonate Substrate: Slide glass Substrate temperature: 200 ° C Back pressure: 1.0 × 10 ^-3 Torr or less Material temperature: 100 ° C High frequency power: 100 W, 13.56 MHz Discharge time: 10 minutes The obtained film is yellow-green And the film thickness was 1400 mm. According to the electron diffraction pattern, this film was a polycrystal composed of Cu, Cu ₂ O, and CuO. -C from XPS spectrum and FT-IR spectrum
The presence of H _2- was confirmed, confirming that the polymer was present in the membrane. In addition, the transmittance of the film is 400 to 700 nm.
It was 25-50% (Fig. 14).

When this film was irradiated with an electron beam (3438 μc / cm ² ),
Bits having a line width of 10.0 μm were clearly formed. Observation with an optical microscope revealed that the bit forming portion reflected light well and the contrast was extremely high. At this time, the transmittance of the film was reduced to 2.5% or less at 400 to 700 nm (FIG. 14). The peak around 550 nm indicates the production of metallic copper.

The bit was erased by heat-treating the film after bit formation (after recording) in air at 200 ° C. for 1 minute. This recording and erasing could be repeated.

In addition, since the recording mechanism is a reduction reaction of copper oxide, there was no swelling at the peripheral portion of the recording which was observed in a melt evaporation type memory medium, and the recording medium was extremely smooth. Further, since the hydrocarbon polymer protects Cu, Cu ₂ O, and CuO particles, the stability during recording and during non-recording was increased.
In this example, the substrate temperature is 100 ° C or more,
In the following cases, copper oxide is generated to such an extent that recording by electron beam irradiation is possible.

Example 20 as starting material A film was produced in the same manner as in Example 19 except that was used. This was found to have the same effect as the film obtained in Example 19.

Example 21 A film was produced in the same manner as in Example 19 except that copper oxalate was used as a starting material. This was found to have the same effect as the film obtained in Example 19.

Example 22 A film was produced in the same manner as in Example 19 except that copper acetate was used as a starting material. This was found to have the same effect as the film obtained in Example 19.

Example 23 A film was produced in the same manner as in Example 19 except that copper formate was used as a starting material. This film had the same effect as the film obtained in Example 19.

[Effect] When the memory medium of the present invention is composed of fine metal particles, the resolution of the recording bit is high, and when the medium contains a metal oxide, the recording bit can be formed by irradiating an electron beam. The record can be erased by heat treatment and used again.

The recording bit part formed by laser is 1500-45
Since it has a flat smooth raised shape with a height of 00 ° and a large change in reflectance before and after recording, a high contrast can be obtained between a recorded portion and a non-recorded portion.

Further, unlike the melting and sublimation type memory materials using simple heat such as metal chalcogens and organic compounds, there is no change in the shape of the bit peripheral portion and no reduction in C / N during reproduction.

Further, both the recorded portion and the non-recorded portion are protected by a hydrocarbon polymer, and the life of the recording bit is long and the moisture resistance is good.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a plasma CVD apparatus, FIG. 2 is a graph showing a relationship between a film forming time and a film thickness of a CuAA plasma CVD thin film, and FIG. 3 is a diagram showing a relationship between a thickness and a reflectance of the CuAA plasma CVD thin film. Graph, FIG. 4 is a graph showing the relationship between the thickness and the absorptivity of the CuAA plasma CVD thin film, FIG. 5 is a graph showing the relationship between the thickness and the transmittance of the CuAA plasma CVD thin film, and FIG. 6 is the plasma power in the CuAA plasma CVD. FIG. 7 is a graph showing the relationship between the plasma power in CuAA plasma CVD and the reflectance of the obtained film, and FIG. 8 is a graph showing the relationship between the plasma power in CuAA plasma CVD and the obtained film. 9 is a graph showing the relationship between the plasma power in CuAA plasma CVD and the transmittance of the obtained film, and FIG. 10 is the transmission and reflection of the Co (II) acetylacetonate plasma CVD thin film. ,absorption Spectrum (Example 12), Fig. 11 shows transmission, reflection and absorption spectra of Co (III) acetylacetonate plasma CVD thin film (Example 13), Fig. 12 shows transmission of Co (II) acetylacetonate plasma CVD thin film FIG. 13 is a schematic view showing a plasma CVD apparatus used in Examples 19 to 23, and FIG. 14 is a diagram of a film of the recording material obtained in Example 19 before and after recording. 4 is a graph showing transmittance.

Continuation of the front page (56) References JP-A-59-20698 (JP, A) JP-A-59-67088 (JP, A) JP-A-59-3729 (JP, A) (58) Fields investigated (Int) .Cl. ⁶ , DB name) B41M 5/26

Claims (2)

(57) [Claims] In an optical memory medium having a thin film provided on a substrate, the thin film is formed by reactive sputtering, reactive deposition, plasma CVD, or photo CVD, and fine metal particles are dispersed in a hydrocarbon polymer. An optical memory medium characterized by comprising: 2. The optical memory medium according to claim 1, wherein the metal fine particles are metal oxide fine particles.