WO2008075683A1 - Optical information recording medium - Google Patents
Optical information recording medium Download PDFInfo
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- WO2008075683A1 WO2008075683A1 PCT/JP2007/074319 JP2007074319W WO2008075683A1 WO 2008075683 A1 WO2008075683 A1 WO 2008075683A1 JP 2007074319 W JP2007074319 W JP 2007074319W WO 2008075683 A1 WO2008075683 A1 WO 2008075683A1
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- WIPO (PCT)
- Prior art keywords
- recording
- alloy
- recording film
- optical information
- film
- Prior art date
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Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
- G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
- G11B7/2437—Non-metallic elements
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
- G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
- G11B7/2433—Metals or elements of Groups 13, 14, 15 or 16 of the Periodic Table, e.g. B, Si, Ge, As, Sb, Bi, Se or Te
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
- G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
- G11B2007/24302—Metals or metalloids
- G11B2007/2431—Metals or metalloids group 13 elements (B, Al, Ga, In)
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
- G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
- G11B2007/24302—Metals or metalloids
- G11B2007/24312—Metals or metalloids group 14 elements (e.g. Si, Ge, Sn)
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
- G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
- G11B2007/24318—Non-metallic elements
- G11B2007/2432—Oxygen
Definitions
- the present invention relates to an optical information recording medium.
- the optical information recording medium of the present invention is used as the current CD (Compact Disc) and DVD (Digital Versatile Disc), the next generation optical information recording medium HD DVD and BD (Blu-ray Disc), and in particular, blue-violet. It is suitably used as a write-once type high-density optical information recording medium.
- Optical information recording media are roughly classified into three types: read-only, rewritable, and write-once types, depending on the recording and playback method.
- write-once optical discs record data using changes in the physical properties of recording films (hereinafter also referred to as recording layers and optical recording films) irradiated with an energy beam such as laser light. To do.
- a write-once optical disc can record information, but it cannot be erased or rewritten.
- write-once optical discs such as CD-R, DVD-R, and DVD + R are used for applications that require data tampering prevention such as document files and image files.
- organic dye materials such as cyanine dyes, phthalocyanine dyes, and azo dyes are known.
- this organic dye material is irradiated with a laser beam, the dye and the substrate are decomposed, melted and vaporized by the heat absorption of the dye to form a recording mark.
- organic dye material it is necessary to dissolve the dye in an organic solvent and then apply it onto the substrate, resulting in low productivity! There is also a problem in terms of long-term stable storage of recorded signals.
- Non-patent Document 1 Patent Documents 1 to 9, etc.
- phase change Te oxide
- alloying Cu and Si laminated structure, etc.
- Patent Document 1 discloses a single-layer type inorganic material thin film
- Patent Document 2 discloses a two-layer type.
- This punching method has a problem that the recording sensitivity is lower than the recording method due to phase change or alloying of the inorganic material thin film.
- This local recording mark forming method is a method in which an inorganic material thin film as a recording film is melted with a laser beam to form holes, pits, and the like. For this reason, it is necessary to raise the temperature to above the melting point of the inorganic material thin film, and inevitably high laser power is required.
- the thin film of the inorganic material is melted, and the melted film tends to remain like water droplets in a portion where holes, pits, and the like are formed.
- the presence of the remaining droplet-like molten film hinders the change in reflectivity of the recording mark portion and prevents the signal modulation from increasing.
- Non-Patent Document 1 discloses a technique of using a Te thin film having a low melting point and low thermal conductivity to make a recording mark hole with low laser power.
- Patent Documents 3 and 4 disclose optical information recording films in which a reaction layer made of a Cu-based alloy containing A1 and a reaction layer containing Si or the like are laminated on a substrate.
- the region where the elements contained in each reaction layer are mixed is partially formed on the substrate by the laser beam irradiation, and the reflectivity changes greatly. Therefore, it is described that recording can be performed with high sensitivity using a short wavelength laser such as a blue laser.
- Patent Documents 5, 6 and 9 prevent a decrease in signal C / N ratio (carrier-to-noise ratio) due to a recording mark, and a high signal C / N and reflection.
- An optical information recording medium having a high efficiency is disclosed, and a Cu-based alloy containing In as a recording film (Patent Document 5), an Ag-based alloy containing Bi (Patent Document 6), an Sn-based alloy containing Bi, etc. (Patent Document 9) are listed.
- Patent Documents 7 and 8 relate to an optical information recording medium using a Sn-based alloy.
- Patent Document 7 includes two or more elements that can be aggregated at least partially in the heat treatment step in the alloy layer.
- An optical information recording medium is disclosed. Specifically, it is an optical information recording medium having a high melting point and a high thermal conductivity, comprising a Sn—Cu based alloy layer having a thickness including Bi and In;
- Patent Document 8 discloses an optical information recording film in which an oxidizable substance that is easier to oxidize than Sn or Bi is added to an Sn-Bi alloy having excellent recording characteristics. It is emphasized that it shows excellent durability.
- Patent Document 1 JP-A 52-130304
- Patent Document 2 Japanese Patent Publication No. 53-31104
- Patent Document 3 JP 2004-5922 Noriyuki
- Patent Document 4 JP 2004-234717 A
- Patent document 5 JP 2002-172861 A
- Patent Document 6 JP 2002-144730 A
- Patent Document 7 Japanese Patent Laid-Open No. 2-117887
- Patent Document 8 JP 2001-180114 A
- Patent Document 9 JP 2002-225433 A
- Japanese Patent Laid-Open No. 2-117887 discloses 55 mass% 11-40 mass% 31-5 quality i% Cu alloy (in terms of atomic%, 53.5 atomic% 11-37.7 atoms % 31-8.8 atom% Cu alloy) is disclosed.
- this optical recording film composition it is difficult to obtain a practical signal C / N ratio.
- the thickness of the alloy layer disclosed in this patent document is 2 to 4 nm. For the above alloy composition, the film thickness is too thin, and thus a practically usable reflectance was not obtained.
- Japanese Patent Application Laid-Open No. 2001-180114 discloses an optical recording film in which an Sn-Bi alloy is added with an oxidizable substance that is more easily oxidized than Sn or Bi.
- a signal C / N ratio and recording sensitivity at levels exceeding those of the Sn-based alloy recording film of the present invention described later were not obtained.
- Sn based alloy of the optical recording layer alloy composition is 84 atomic 0/0 Sn- 10 atoms 0/0 Z n- 6 atomic% 313 discloses ing.
- the signal strength nor the Sn-base alloy provided a signal C / N ratio, recording sensitivity, or reflectivity that exceeded the level of the Sn-base alloy of the present invention described later.
- the metal-based recording film has a great advantage that the material is remarkably stable as compared with the organic recording film, as described above. For this reason, the development of a practical recording film that satisfies the above-mentioned characteristics with metallic materials can be achieved by using BD (Blu-ray Disc) —R, HD DVD ( Digital Versatile Disc) —R is extremely important in providing users with R.
- BD Blu-ray Disc
- HD DVD Digital Versatile Disc
- the present inventors have developed a next-generation blue-purple that satisfies the required characteristics shown in the above (1) to (4), has high recording accuracy, and is inexpensive in terms of cost. It was found that a 1n alloy having a low melting point and a low environmental load is suitable as a hole-drilling recording film with good recording sensitivity using a laser.
- the recording film (optical information recording film) made of the In alloy can provide good recording characteristics, but the recording sensitivity (drilling sensitivity) is not sufficient. The problem of the need for high laser power was clarified.
- the present invention has been made by paying attention to such a situation, and the object thereof is to enable drilling (recording) with a relatively low laser power, and while having good recording characteristics, It is an object of the present invention to provide an optical information recording medium having a recording film capable of obtaining a good signal modulation degree.
- the gist of the optical information recording medium according to the present invention for achieving this object is an optical information recording medium having a recording film on which a recording mark is formed by irradiation of an energy beam. Is composed of a mixture of In alloy and oxide.
- the In alloy in the recording film of the optical information recording medium preferably contains 1 to 65 atomic% of one or two kinds of Ni and Co, with the balance being In and inevitable impurities. Further, the content of one or two of Ni and Co in the In alloy is preferably 50 atomic% or less. Further, the content of one or two of Ni and Co in the In alloy is preferably 20 atomic% or more. In addition, the In alloying force containing Ni and Co, and further containing 19 atomic% or less (not including 0 atomic%) of one or more selected from Sn, Bi, Ge and Si S preferable.
- the oxide in the recording film of the optical information recording medium is preferably one kind selected from silicon, aluminum and niobium oxides, or a composite oxide of two or more kinds thereof. Further, the mixing ratio of the In alloy and the oxide in the recording film of the optical information recording medium is a volume ratio of the In alloy to the oxide (In alloy volume) / (oxide volume) of 3 to 10; Preferred to be in the range! / ,.
- the recording film of the optical information recording medium is composed of a mixture of an In alloy and an oxide that is a dielectric component, so that heat transfer of these mixture recording films (optical information recording film) is achieved.
- the conductivity and suppressing the diffusion of heat input by the laser it becomes possible to use energy efficiently.
- the thermal conductivity of a recording film made of a mixture of an In alloy and an oxide is significantly lower than that of a recording film formed only of an In alloy.
- the diffusion of heat input by the laser in the recording film can be suppressed. Therefore, a recording film made of a mixture of In alloy and oxide can be melted with a lower laser power, and local recording marks (holes, pits, etc.) can be formed with a lower laser power. As a result, it is possible to obtain a recording film that has a good recording characteristic and a better signal modulation degree.
- FIG. 1 is a schematic cross-sectional view showing an embodiment of the optical information recording medium of the present invention.
- FIG. 2 is a schematic cross-sectional view showing another embodiment of the optical information recording medium of the present invention.
- FIG. 3 is a schematic cross-sectional view showing another embodiment of the optical information recording medium of the present invention.
- FIG. 4 is a schematic cross-sectional view showing another embodiment of the optical information recording medium of the present invention.
- FIG. 5 is an explanatory diagram showing the relationship between the recording laser power of the recording film and the signal modulation degree in Example 1.
- FIG. 6 is an explanatory diagram showing the relationship between the recording laser power of the recording film and the signal C / N ratio in Example 1.
- FIG. 7 is an explanatory view showing the result of measuring the thermal conductivity of the recording film in Example 1.
- FIG. 8 is an explanatory diagram showing the relationship between the recording laser power of the recording film and the signal modulation degree in Example 2.
- FIG. 9 is an explanatory diagram showing the relationship between the recording laser power of the recording film and the signal C / N ratio in Example 2.
- FIG. 10 is an explanatory diagram showing the relationship between the recording laser power of the recording film and the signal modulation degree in Example 3.
- FIG. 11 is an explanatory diagram showing the relationship between the recording laser power of the recording film and the signal C / N ratio in Example 3.
- FIGS.! To 4 exemplify a write-once type optical information recording medium of the present invention capable of recording and reproducing data by irradiating a recording film with an energy beam such as a laser beam having a wavelength of about 350 to 700 nm.
- an energy beam such as a laser beam having a wavelength of about 350 to 700 nm.
- FIG. 1 and Fig. 2 (A) and Fig. 3 (B) and (B) and (D) in FIG. 4 are those in which the recording location is formed in a convex shape
- FIG. 1, (B) in FIG. 2, (A) in FIG. 3 and (A) in FIG. (C) shows an example in which the recording location is concave.
- An optical disc 10 in FIG. 1 includes a support substrate 1, an optical adjustment layer 2, dielectric layers 3 and 5, and a dielectric layer.
- a recording film 4 sandwiched between 3 and 5 and a light transmission layer 6 are provided.
- the optical disk 10 in FIG. 2 includes a support substrate 1, a 0th recording film group (a group of layers including an optical adjustment layer, a dielectric layer, and a recording film) 7A, an intermediate layer 8, and a first recording film.
- a group (a group of layers including an optical adjustment layer, a dielectric layer, and a recording film) 7B and a light transmission layer 6 are provided.
- Fig. 3 shows an example of a single-layer DVD-R, single-layer DVD + R, single-layer HD DVD-R type optical disc
- Fig. 4 shows a double-layer DVD-R, dual-layer DVD + R, double-layer.
- HD DVD Example of R type optical disc.
- Reference numeral 8 denotes an intermediate layer
- reference numeral 9 denotes an adhesive layer.
- the group of layers constituting the 0th and 1st recording film groups 7A and 7B in Figs. 2 and 4 consist of only one recording film in addition to the three-layer structure or the two-layer structure. It doesn't matter.
- the three-layer structure is composed of a dielectric layer / recording film / dielectric layer, a dielectric layer / recording film / optical adjustment layer, a recording film / dielectric layer / optical adjustment layer, etc. from the upper side of the figure.
- the two-layer structure is composed of a recording film / dielectric layer, a dielectric layer / recording film, a recording film / optical adjustment layer, an optical adjustment layer / recording film, and the like from the upper side of the figure.
- the recording film 4 is made of a mixture of an In alloy and an oxide such as SiO. It is characterized by enabling high density.
- the optical information recording medium of the present invention selectively has dielectric layers 3 and 5 adjacent to the recording film 4 made of a mixture of this In alloy and oxide.
- dielectric layers 3 and 5 are provided, Si
- the main component is an oxide of an element selected from Mg, Ta, Zr, Mn, In and the like.
- the dielectric layers 3 and 5 made of these oxides have a dielectric film and a recording film made of a mixture of an In alloy and an oxide when forming a local recording mark with laser power. Control the wettability of 4. This makes it possible to form local recording marks with laser power. In this way, it is possible to suppress the uneven distribution of the molten In in the form of water droplets and the uneven distribution of In as a mass, and to improve the formation of local recording marks. This prevents a decrease in signal modulation. Further, the dielectric layer made of these oxides also has a dielectric function (effect) that protects the recording film 4 and increases the reflectance and the signal C / N ratio as the dielectric layer.
- the dielectric layers 3 and 5 are adjacent to the recording film 4 made of a mixture of In alloy and oxide in order to control the wettability of the recording film and perform the dielectric function.
- the dielectric layer 3 is preferably located between the recording film 4 and the substrate 1.
- the dielectric layer 5 is preferably located between the recording film 4 and the light transmission layer 6.
- the force S for forming the recording film 4 from a mixture of an In alloy and an oxide such as SiO first, the composition of the In alloy will be described below.
- the melting point of pure In is a low melting point of 156.6 ° C, which is significantly lower than that of Al at 660 ° C, Ag at 962 ° C, and Cu at 1085 ° C. For this reason, In can be melted and deformed even at a lower temperature with low laser power, and there is a possibility that the above-mentioned local recording marks (holes, pits, etc.) can be formed with good marking performance.
- the melting point is too low, and the surrounding recording film not irradiated with the laser is melted at the time of the local recording mark by laser irradiation. Is likely to get worse.
- the surface roughness of the formed recording film becomes rough, and there is a disadvantage that the reflectance and sensitivity are low in environmental resistance.
- the composition of the In alloy preferably includes 1 to 65 atomic percent of one or two of Ni and Co, and the balance is In and unavoidable impurities.
- the upper limit of the content of one or two of Ni and Co is preferably 50 atomic%.
- the lower limit of the content of one or two of Ni and Co is preferably 20 atomic%. That is, the content range of one or two of Ni and Co is set to a narrow range of 1 to 50 atomic percent or a narrow range of 20 to 65 atomic percent with respect to the range of! Is preferably in a narrower range of 20 to 50 atomic%.
- the composition of the In alloy is composed of the balance In and unavoidable impurities.
- Examples of elements belonging to Group 8 of the periodic table having such effects include Fe, Ru, Rh, Pd, Os, Ir, Ni, Co, and Pt in addition to Ni and Co. However, the effects of Ni and Co are significantly greater than these elements. In addition, it is allowed to contain the above-mentioned Fe, Ru, Rh, Pd, Os, Ir, Pt, etc. as (unavoidable) impurities.
- the composition of the In alloy is that, as described above, In contains one or two kinds of Ni and Co, and further contains one or more kinds of Sn, Bi, Ge and Si at 19 atomic% or less. Lower (not including 0 atomic%) can be included. By including these Sn, Bi, Ge and Si in addition to Ni and Co, the jitter value can be further reduced. Although this mechanism is not necessarily clear, it is presumed that Sn, Bi, Ge, and Si achieve lateral heat bleed suppression by lowering the thermal conductivity without increasing the melting point.
- the composition of the In alloy includes 1 to 65 atomic% of one or two kinds of Ni and Co, and further 19 atomic% or less (0 atomic%) of one or more kinds of Sn, Bi, Ge and Si. Contained, and the remainder shall consist of In and inevitable impurities. At this time, the content of one or two of these Ni and Co may be made narrower within the above preferred ranges.
- the recording film 4 is composed of such a mixture of In alloy and oxide.
- the thermal conductivity of the recording film 4 is controlled.
- the laser is used. This makes it possible to use the energy more efficiently by suppressing the diffusion of the input heat.
- This oxide is one kind of force selected from silicon, aluminum and niobium oxides, or two or more kinds of these widely used as dielectric layer components as the dielectric layers 3 and 5.
- a composite oxide is preferable. That is, the oxide is preferably composed of one (single) oxide selected from SiO, Al 2 O, NbO, NbO, Nb 2 O, or the like, or two or more (plural) complex oxides.
- oxides used as the dielectric layer component include oxides of elements selected from Mg, Ta, Zr, Mn, In, and the like, which can be used. However, among these, it is mixed with In alloy to lower the thermal conductivity of the In alloy film, and the recording film 4 having the functions of the dielectric layers 3 and 5 is highly effective for silicon, aluminum and aluminum.
- Niobium oxide is one kind of force selected from silicon, aluminum and niobium oxides, or two or more kinds of these widely used as dielectric layer components as the dielectric layers 3 and 5.
- a composite oxide is preferable. That is
- the thermal conductivity of the recording film 4 of this mixture becomes lower than that of the In alloy alone. For this reason, it is possible to suppress the diffusion of the heat input by the laser and to efficiently use the energy for forming the local recording mark.
- the mixture of the In alloy and the oxide that is a dielectric component can be melted by a lower laser power, and local recording marks can be formed. Become. As a result, it is possible to obtain a recording film having better recording characteristics and a better signal modulation degree than that of the recording film 4 made of only In alloy.
- the recording film 4 made of a mixture of In alloy mixed with an oxide can be melted and deformed even at a lower temperature than the low laser performance, but the surrounding recording film not irradiated with the laser is dissolved.
- An appropriate melting point can be obtained without melting. This effect can be exhibited by low laser power marking of laser light of each wavelength of 810 nm to 405 nm used for marking.
- the surface roughness of the recording film can be kept small, and high reflectivity, high sensitivity, and high environmental resistance can be obtained within the range of the film thickness of the recording film described later.
- the recording film 4 made of a mixture of an In alloy and an oxide
- the recording film 4 in which the dielectric layers 3 and 5 and the recording film 4 are mixed is formed.
- the recording film 4 having the functions of the dielectric layers 3 and 5 is formed.
- it is compatible with optical information recording and reproduction technology using short-wavelength lasers such as blue-violet lasers. Allows densification and guarantees.
- (1) high-quality signal writing / reading such as (1) high signal C / N ratio and low jitter, (2) in addition to high recording sensitivity, (3) high reflection from recording film Rate, (4) high corrosion resistance, etc. can be made possible. Further, the recording accuracy is high and the cost is low, and a practical recording film can be obtained.
- the mixing ratio of the In alloy and the oxide such as SiO in the recording film 4 (the mixing ratio of the oxide to the In alloy) is determined, and the volume of the In alloy and the oxide is determined.
- the ratio (In alloy volume) / (oxide volume) is preferably 3 to 10;
- the recording film 4 made of a mixture of the In alloy and the oxide has a thickness in the range of 1 to 50 nm, depending on the structure of the optical information recording medium, in order to form a reliable recording film with stable accuracy. It is good to do.
- the recording film 4 consisting of a mixture of In alloy and oxide in this thickness range shows high recording sensitivity, especially for laser light with a wavelength in the range of 350 to 700 nm, and excellent optical information writing / reading accuracy. It becomes an optical information recording medium to be exhibited.
- the thickness of the recording film is less than 1 nm, the optical recording film is too thin. Therefore, even if an optical adjustment layer or a dielectric layer is provided above or below the optical recording film, a pore is formed on the film surface of the optical recording film. If defects such as these are likely to occur, it will be difficult to obtain satisfactory recording sensitivity.
- the more preferable thickness of the recording film is 8 nm or more and 30 nm or less, more preferably 12 nm or more and 20 nm or less when no dielectric layer or optical adjustment layer is provided.
- the thickness is 3 nm or more and 30 nm or less, more preferably 5 nm or more and 20 nm or less.
- the recording film 4 made of the mixture of In alloy and oxide of the present invention formed the recording film 4 in which the dielectric layers 3 and 5 and the recording film 4 were mixed. It can be said that the recording film 4 having the function of 5 was formed. Therefore, a mode in which the dielectric layers 3 and 5 are not provided is possible.
- an oxide of a specific element selected from Si, Al, Nb, Mg, Ta, Zr, Mn, and In is used.
- the dielectric layers 3 and 5 are preferably provided. Examples of these suitable oxides include SiO, Al 2 O, NbO, NbO, Nb 2 O, MgO, Ta 2 O, ZrO, MnO, and InO.
- the dielectric layers 3 and 5 made of oxides of these elements control the wettability of the In-based alloy recording film 4 when a local recording mark is formed with laser power. Reduces signal modulation.
- the dielectric layers 3 and 5 protect the recording film 4 as a dielectric layer, thereby greatly extending the storage period of recorded information (improves durability), and reflectivity and signal C / It also has the effect of increasing the N ratio.
- the dielectric layers 3 and 5 made of oxides of these elements have the effect of the present invention of the dielectric layers on the formation of the dielectric layers, even if the dielectric layers are not only made of oxides of these elements. In the range that does not inhibit the above, it is allowed to contain oxides other than the oxides of these elements as impurities in the dielectric layer. Of course, if possible, a dielectric layer consisting essentially of oxides of these elements may be formed.
- the thickness of these dielectric layers 3 and 5 is preferably in the range of 5 to 200 nm, depending on the structure of the optical information recording medium, in order to exert the effect of suppressing the decrease in the signal modulation. Is in the range of 10 to 150 nm. If the thickness is less than 5 nm, the dielectric layer is too thin. Even if a dielectric layer is provided, the above effect is not exhibited. On the other hand, if it is too thick, the effect is not improved. If it is too thick, there is a disadvantage that the productivity of the optical information recording medium is reduced. Therefore, it is not necessary to increase the thickness beyond 200 nm.
- the means for forming the oxide layer of the specific element is not particularly limited, but the sputtering method is preferable!
- the optical disk as a representative embodiment of the present invention includes the dielectric layers 3 and 5 including the dielectric layers 3 and 5 in the case where the oxide layer of the specific element other than the recording film 4 is not used.
- the materials such as the optical adjustment layer 2 and the like are not particularly limited, and those usually used can be appropriately selected and used.
- the material for the support substrate generally used polycarbonate resin (also referred to as PC substrate), norbornene-based resin, cyclic olefin-based copolymer, amorphous polyolefin and the like are preferably used.
- As a material for the optical adjustment layer Ag, Au, Cu, Al, Ni, Cr, Ti, or an alloy thereof is preferably used.
- the preferred wavelength of the laser beam irradiated for recording is in the range of 350 to 700 nm. If it is less than 35 Onm, light absorption by the cover layer (light transmission layer) becomes significant, making it difficult to write to and read from the optical recording film. become. Conversely, if the wavelength exceeds 700 nm and becomes excessive, the energy of the laser beam is reduced, making it difficult to form a recording mark on the optical recording film. From this point of view, the more preferable wavelength of the laser beam used for recording information is 350 nm or more and 660 or less, more preferably 380 or more and 650 or less.
- the composition of the sputtering target used for forming the recording film or dielectric layer is basically the same as the desired alloy composition or oxide composition of the recording film or dielectric layer described above. Can be used. In other words, a set of sputtering targets By making the composition the same as the alloy composition and oxide composition of the recording film and dielectric layer described above, the recording film and dielectric layer formed by sputtering are formed into a desired alloy composition and oxide composition. be able to.
- the recording film made of the mixture of the In alloy and the oxide of the present invention uses a separate In alloy target and an oxide target such as SiO, respectively, and a predetermined mixing ratio of the recording film described above.
- the sputtering conditions are controlled so that each is sputtered simultaneously (co-sputtering), and DC sputtering or RF sputtering is used.
- a single sputtering target was prepared by previously mixing an oxide such as SiO in the In alloy at a predetermined mixing ratio of the recording film described above, and this was performed by DC sputtering or RF sputtering.
- the recording film of the present invention can be formed by sputtering.
- the recording film of the present invention can be formed in which the In alloy and the oxide are uniformly dispersed and mixed, and the film quality of the mixture is homogenized.
- the signal modulation degree and signal C / N ratio of each recording film made of a mixture of In alloy and oxide SiO were measured and evaluated.
- an optical disk 10 of the type shown in FIG. 1 is prototyped, and a recording film 4 and a light transmission layer 6 are provided on the support substrate 1 in this order, and two layers are provided in that order.
- Signal modulation and signal C / N ratio were measured and evaluated.
- the results are shown in Figs.
- the thermal conductivity of each recording film consisting of a mixture of In alloy and oxide SiO The rate was measured.
- the result is shown in FIG. 5 and 6, the line connecting the diamond marks is Invention Example 1, the line connecting the square marks is Invention Example 2, the line connecting the triangle marks is Comparative Example 1, and the line connecting the X marks is Comparative Example 2. .
- Inventive Examples 1 and 2 in FIGS. 5, 6 and 7 have a recording film made of an appropriate amount of a mixture of In alloy and SiO, as will be described later.
- Comparative Example 1 is a recording film made of only an In alloy
- Comparative Example 2 is a recording film in which the amount of SiO mixed is too large.
- Invention Examples 1 and 2 having a recording film made of an appropriate amount of a mixture of In alloy and SiO have a laser power of about 8 mW compared to Comparative Example 1 and Comparative Example 2. Of course, even with a lower laser power of around 5 mW, the signal modulation and signal C / N ratio are high.
- Invention Example 1 and Invention Example 2 which are recording films made of a mixture of In alloy and SiO, are formed only of In alloy! /, Compared with the recording film of Comparative Example 1. This confirms that the thermal conductivity is greatly reduced.
- the light transmission layer 6 was directly provided on the film 4, and the optical adjustment layer 2 and the dielectric layers 3 and 5 were not provided.
- a polycarbonate substrate (thickness 1. lmm, track pitch 0.32 111, groove width 0.116 111, groove depth 25 nm) was used.
- an In—25at% Ni In alloy with a thickness of 12 nm was formed by DC sputtering using co-sputtering, and at the same time, SiO equivalent to 1.5 nm was formed by RF sputtering. did.
- a recording film 4 having a total film thickness of 13.5 nm was formed so that the mixing ratio of In alloy / SiO dielectric was 8: 1 by volume.
- the composition of each target used for film formation and the film composition of each recording film formed were measured by ICP emission spectrometry or ICP mass spectrometry.
- an ultraviolet curable resin manufactured by Nippon Kayaku Co., Ltd., trade name: "BRD-1" 30 ” was spin-coated, and then cured by UV to form a light transmission layer 6 having a thickness of 100 ⁇ 15 m.
- Inventive Example 2 used the same (condition) polycarbonate substrate as Inventive Example 1. On the substrate surface, an In-25at% Ni In alloy equivalent to 12 nm in thickness equivalent to that of Invention Example 1 was formed by DC sputtering using co-sputtering, and at the same time by RF sputtering as in Invention Example 1. A SiO film having a thickness of 3 nm was formed. Then, a recording film 4 having a total film thickness of 15 nm was formed such that the mixing ratio of In alloy / SiO 2 dielectric material was 4 in the volume ratio.
- Comparative Example 1 used the same (condition) polycarbonate substrate as Invention Example 1. On the substrate surface, a recording film 4 made of only an In-25 at% Ni alloy equivalent to a thickness of 12 nm was formed by DC sputtering as in Invention Example 1.
- Comparative Example 2 the same polycarbonate substrate (under the same conditions) as in Invention Example 1 was used. On the substrate surface, an In-25at% Ni In alloy equivalent to 12nm in thickness equivalent to that of Invention Example 1 was deposited by DC sputtering using co-sputtering. At the same time, RF sputtering method was used as in Invention Example 1. Thus, a SiO film having a thickness of 6 nm was formed. Then, a recording film 4 having a total film thickness of 18 nm was formed so that the mixing ratio of In alloy / SiO dielectric was 2: 1 by volume.
- FIG. 5 shows the relationship between the recording laser power and the signal modulation degree in each of the optical recording media of Invention Examples 1 and 2 and Comparative Examples 1 and 2, respectively.
- This measurement was performed using an optical disk evaluation device (ODU-1000 (trade name) manufactured by Pulstec Industrial Co., Ltd., recording laser wavelength: 405 nm, NA (numerical aperture): 0.85) and a digital oscilloscope (manufactured by Yokogawa Electric Corporation, Using the product name “DL1640L”), the degree of signal modulation was measured. More specifically, a recording mark of 0.660 111 in length was repeatedly formed at a linear velocity of 4.9 m / s in the range of laser power 4 mW to 12 mW, and the signal at the time of signal reading at laser power 0.3 mW The degree of modulation was measured.
- ODU-1000 trade name
- NA number of numerical aperture
- the signal modulation degree means (signal intensity max—signal intensity min) / (signal intensity max) 100 (unit%) of the obtained signal. In order to obtain desired recording characteristics, It is generally considered that a signal modulation degree of 50% or more is required.
- FIG. 6 shows the relationship between the recording laser power and the signal C / N ratio in each of the optical recording media of Invention Examples 1 and 2 and Comparative Examples 1 and 2, respectively.
- the signal C / N ratio was measured using an optical disk evaluation apparatus (same as above) and a spectrum analyzer (trade name “R3131A”) at the same time as the signal modulation degree measurement of the optical disk in FIG. (Unit: dB) was measured. More specifically, a recording mark with a length of 0.60 m is repeatedly formed at a linear speed of 4.9 m / s in the range of laser power 4 mW to 12 mW, and 4.12 MHz when reading a signal with a laser power of 0.3 mW.
- the signal C / N ratio (unit: dB), which is the ratio when the signal strength of the frequency component is the carrier (unit: dB) and the noise of the signal strength of the frequency component before and after that (unit: dB), was measured.
- the C / N ratio of the same signal of the optical disc needs to be at least 45 dB! /.
- the mixing ratio of SiO to the In alloy is too high at 2 in the volume ratio of In alloy volume / oxide volume.
- the signal C / N ratio remained below 45 dB for all recording powers. This result confirms that when the mixing ratio of SiO to the In alloy is set to a certain level or more, there is an adverse effect that the signal quality is deteriorated. Therefore, the mixing ratio of SiO to In alloy is suitably in the range of 3 to 10 in terms of the volume ratio of In alloy to oxide (In alloy volume) / (oxide volume).
- Equation 1 K: thermal conductivity (W / mK), ⁇ : electric conductivity (S / m), L: mouth one Lenz number (2. 45 X 10- 8 W ⁇ / K 2 ), T: Absolute temperature (K), respectively.
- Invention Example 1 and Invention Example 2 which are recording films made of a mixture of In alloy and SiO, have a thermal conductivity as compared with the recording film of Comparative Example 1 formed only of In alloy. This confirms that the rate will decline significantly. As a result, the recording film made of a mixture of In alloy and SiO can suppress the diffusion of heat input by the laser, and a local recording mark can be formed with a lower laser power. As a result, as described above, it is proved that there is an effect of obtaining a recording film that has a good recording characteristic and can obtain a better signal modulation degree.
- the signal modulation degree and signal C / N ratio of a recording film made of a mixture of an In alloy and oxides of Al 2 O and Nb 2 O were measured and evaluated.
- the type shown in Fig. 1 is the same as in Example 1.
- Invention Example 3 having an appropriate amount of mixture of In alloy and Al 2 O of the present invention, and an appropriate amount of mixture of In alloy and Nb 2 O Inventive example 4 having a recording film made of is superior in signal modulation degree and signal C / N ratio to Comparative Example 1 (same as Example 1) of a recording film made only of In alloy! /, It was.
- FIGs. 8 and 9 the line connecting the diamond marks is again shown (same as in Example 1), Invention Example 2, the line connecting the square marks is Invention Example 3, the line connecting the triangle marks is Invention Example 4, The line connecting the X marks is Comparative Example 1.
- Invention Example 1 The same (condition) polycarbonate substrate as in Invention Example 1 was used.
- Invention Example 1 an In-25 at% Ni In alloy equivalent to a thickness of 12 nm was formed on the surface of the substrate by DC sputtering using co-sputtering, and at the same time, equivalent to 3 nm in thickness by RF sputtering.
- a film of AlO was formed.
- a recording film 4 having a total film thickness of 15 nm was formed so that the mixing ratio of In alloy / Al 2 O dielectric was 4 in the volume ratio.
- Invention Example 3 and Invention Example 4 which are recording films made of a mixture of In alloy and Al 2 O or Nb 2 O
- the laser power is 6 mW or less
- the signal modulation degree is 50% or more
- the signal It can be seen that the C / N ratio is 45 dB or more. That is, it is supported that the recording sensitivity can be greatly improved by using an In alloy / Al 2 O or Nb 2 O mixed recording film as compared with Comparative Example 1 in which only the In alloy is used.
- FIG. 10 shows the relationship between the recording laser power and the signal modulation degree in each optical recording medium
- FIG. 11 shows the relationship between the recording laser power and the signal C / N ratio.
- the line connecting the black circles is Invention Example 5, and the line connecting the * marks is Comparative Example 3. From these FIGS. 10 and 11, in Comparative Example 3 in which the recording film is formed only of the In alloy, the laser power necessary for recording, that is, the signal modulation degree is 50% or more and the signal C / N ratio is A laser power of 45 m or more is required.
- Invention Example 5 which is a recording film made of a mixture of In alloy and SiO, the laser power is 6 mW or less, the signal modulation is 50% or more, and the signal C / N ratio is 45 dB or more. I understand that.
- the recording sensitivity can be greatly improved by using an In alloy / SiO mixed recording film as in the present invention.
- the invention example has a laser power of about 8 mW as well as a laser power of about 5 mW, as compared with the comparative example of the recording film made only of the In alloy, as long as it is within the composition range of the present invention. Even with a lower laser power, the effect of high signal modulation and signal C / N ratio can be obtained.
- a polycarbonate substrate having the same conditions as in Invention Example 1 was used as the substrate 1.
- an In alloy containing Co—40 at% Co equivalent to 12 nm in thickness was formed by DC sputtering, and at the same time, SiO equivalent to 1.5 nm in thickness was formed by RF sputtering. (Cosputtering).
- a recording film 4 having a total film thickness of 13.5 nm was formed so that the mixing ratio of In alloy / SiO dielectric was 8: 1 by volume.
- a polycarbonate substrate having the same conditions as in Invention Example 1 was used.
- a recording film 4 made of only an In-40 at% Co alloy equivalent to 12 nm in thickness was formed by DC sputtering as in Invention Example 5.
- the same light transmission layer 6 as that of Invention Example 1 was formed on the recording film 4.
- the sputtering conditions the ultimate vacuum: 3 X 10- 6 Torr or less, Ar gas pressure: 2 mTorr, DC spatter deposition power: was 100W.
- the film thickness was adjusted in the range of 12 to 21 nm so that the unrecorded SUM2 signal level of the BD-R disc (output signal correlating with reflectivity) was 280 mV or more. Some alloys cannot secure more than 280mV).
- a UV curable resin (trade name “BRD-130” manufactured by Nippon Kayaku Co., Ltd.) was spin-coated thereon, followed by UV curing to form a light transmission layer 3 having a thickness of 100 ⁇ 15 m. .
- optical disk evaluation method is as follows: Optical disk evaluation device (trade name “ODU-1000” manufactured by Pulstec Industrial Co., Ltd., recording laser wavelength: 405 nm, NA (numerical aperture): 0 ⁇ 85), spectrum analyzer (Trade name “R3131R” manufactured by Advantest) was used.
- the linear velocity is 4 ⁇ 9m / s, the unrecorded SUM2 level, and the recording laser power in the range of 4mW to 12mW, the length of 0.6 111 recording mark (corresponds to 811 signal of 2508 8111 & Disc)
- the maximum C / N value at the time of recording / reproducing at the time of signal reading with a reproducing laser power of 0.3 mW was evaluated.
- Table 1 shows examples in which the In alloy of the recording film 4 of the optical disc contains one or two of Ni and Co.
- each example in Tables 1 and 2 means an example of a recording film made of only an In alloy within the composition range of the present invention in Tables 1 and 2, and in each of the above-described Examples;! To 3 It is different from the recording film made of a mixture of In alloy + oxide.
- Comparative Examples 1 to 4 in Table 1 also mean a comparative example of a recording film consisting only of In alloy outside the composition range of the present invention in Table 1, and the Comparative Examples 1 to 3 in FIGS. Is different.
- Table 2 shows examples (invention examples) each including one or more selected from Sn, Bi, Ge, and Si in addition to the In alloying force S, Ni, and Co of the recording film 4 of the optical disk. Recording power and jitter values (3 continuous tracks) with the minimum SUM2 level, C / N value during 8T signal recording and playback, and jitter value (during continuous 3 track recording) It is a table showing (at the time of recording).
- the recording laser power that gives the maximum C / N value is in the range of 6 mW to 10 mW.
- the unrecorded SUM2 level is over 280 mV. Those not satisfying are marked with X.
- ⁇ is marked, and X is marked if it is less than this.
- the optical disk with In alloy recording film 4 containing Ni and Co has a SUM2 level and C / N value that is higher than that of each comparative example (In alloy containing Pt, Au, or V). It can be seen that both have high recording properties. Therefore, the significance of Ni, Co content or Ni, Co content in the In alloy of the recording film comprising the mixture of In alloy and oxide of the present invention is supported.
- the optical disc provided with the In alloy recording film 4 containing Bi, Sn, Ge, and Si also has the same SUM2 level and C / N value.
- the jitter value is lower than that of the reference example corresponding to Example 1 in Table 1 that does not contain Bi, Sn, Ge, and Si, and has excellent recording characteristics. It turns out that But Therefore, the recording film comprising the mixture of In alloy and oxide of the present invention contains Bi, Sn, Ge, and Si in addition to Ni and Co in the In alloy or Bi, Sn, Ge, and Si. The significance of quantity is supported.
- Example 31 In-Co-Ni-Sn Co 41.4at% Ni 8.5at% 12nm O309mV O ⁇ 50dB 6. Mechanical 6.9%
- Example 32 In-Co-Ni-Sn Co 34.0at% Ni 16.6at% 12nrn O308mV O ⁇ 50dB 6.2mW 6.9%
- Example 36 In-Co-Ni-Sn Co 32.2at% Ni 12.5at 11nm 0286mV O ⁇ 50dB 6.2mW 7.8%
- an optical information recording medium having a recording film that enables punching (recording) with a relatively low laser power, has a good recording characteristic, and obtains a better signal modulation degree. can do.
- the optical information recording medium of the present invention is used as a current CD (Compact Disc), DVD (Digital Versatile Disc), or next-generation optical information recording medium (HD DVD or Blu-ray Disc). It is suitably used as a write-once high-density optical information recording medium using a violet laser.
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Abstract
Provided is an optical information recording medium having a recording film where a recording mark is formed by applying an energy beam. The recording film is is formed by a mixture of an In-based alloy and an oxide. The optical information recording medium is used as a currently used CD (Compact Disc), a DVD (Digital Versatile Disc), an HD DVD and a BD (Blu-ray Disc) as optical information recording media of the next generation, and in particular as a write-once type high-density optical information recording medium for which a blue-violet color laser is used.
Description
明 細 書 Specification
光情報記録媒体 Optical information recording medium
技術分野 Technical field
[0001] 本発明は光情報記録媒体に関するものである。本発明の光情報記録媒体は、現行 の CD (Compact Disc)や DVD (Digital Versatile Disc)、次世代の光情報記録媒体 の HD DVDや BD (Blu-ray Disc)として用いられ、特に、青紫色のレーザを用いる 追記型の高密度光情報記録媒体として好適に用いられる。 [0001] The present invention relates to an optical information recording medium. The optical information recording medium of the present invention is used as the current CD (Compact Disc) and DVD (Digital Versatile Disc), the next generation optical information recording medium HD DVD and BD (Blu-ray Disc), and in particular, blue-violet. It is suitably used as a write-once type high-density optical information recording medium.
背景技術 Background art
[0002] 光情報記録媒体 (光ディスク）は、記録再生方式により、再生専用型、書換え型およ び追記型の 3種類に大別される。 [0002] Optical information recording media (optical discs) are roughly classified into three types: read-only, rewritable, and write-once types, depending on the recording and playback method.
[0003] このうち追記型の光ディスクでは、主にレーザ光などのエネルギービームが照射さ れた記録膜 (以下、記録層、光記録膜とも言う）材料の物性の変化を利用してデータ を記録する。追記型の光ディスクは、情報の記録はできるが、消去や書換えを行なう ことはできない。この様な特性を利用し、 CD— R、 DVD-R, DVD + R等の追記型 の光ディスクは、例えば文書ファイルや画像ファイルなど、データの改ざん防止が求 められる用途に用いられてレ、る。 Of these, write-once optical discs record data using changes in the physical properties of recording films (hereinafter also referred to as recording layers and optical recording films) irradiated with an energy beam such as laser light. To do. A write-once optical disc can record information, but it cannot be erased or rewritten. Using these characteristics, write-once optical discs such as CD-R, DVD-R, and DVD + R are used for applications that require data tampering prevention such as document files and image files. The
[0004] 追記型の光ディスクに用いられる記録膜材料としては、例えば、シァニン系色素、フ タロシアニン系色素、ァゾ系色素などの有機色素材料が知られている。この有機色素 材料にレーザ光を照射すると、色素の熱吸収によって色素や基板が分解、溶融、蒸 発されるなどして記録マークが形成される。ところが有機色素材料を用いる場合、色 素を有機溶媒に溶解してから基板上に塗布しなければならず、生産性が低レ、と!/、う 問題がある。また、記録信号の長期安定保存性などの点でも問題がある。 [0004] As recording film materials used for write-once optical disks, for example, organic dye materials such as cyanine dyes, phthalocyanine dyes, and azo dyes are known. When this organic dye material is irradiated with a laser beam, the dye and the substrate are decomposed, melted and vaporized by the heat absorption of the dye to form a recording mark. However, when using an organic dye material, it is necessary to dissolve the dye in an organic solvent and then apply it onto the substrate, resulting in low productivity! There is also a problem in terms of long-term stable storage of recorded signals.
[0005] こうした有機色素材料の弱点を改善するため、記録膜として無機材料薄膜を使用し 、この薄膜にレーザ光を照射して、局所的に記録マーク（穴、ピットなど）を形成する 穴開け方式により記録を行なう方法が提案されている（非特許文献 1、特許文献 1〜 9など)。 [0005] In order to improve the weaknesses of these organic dye materials, an inorganic material thin film is used as a recording film, and this thin film is irradiated with laser light to locally form recording marks (holes, pits, etc.) A method of recording by a method has been proposed (Non-patent Document 1, Patent Documents 1 to 9, etc.).
[0006] なお、このような穴開け方式 (記録マーク形成）の他に、無機材料薄膜の相変化（Te
及び Te酸化物など）や合金化（Cuと Siの積層構造など）により記録する方式もある。し かし、これらは 3層以上の多層の無機材料薄膜をスパッタなどで積層する必要があり 、生産ラインが特殊となり、生産コストの面で不利である。 [0006] In addition to such a drilling method (record mark formation), the phase change (Te There are also recording methods such as Te oxide) and alloying (Cu and Si laminated structure, etc.). However, it is necessary to laminate three or more layers of inorganic material thin films by sputtering or the like, which makes the production line special and disadvantageous in terms of production cost.
[0007] この点、上記穴開け方式は、 2層以下の無機材料薄膜で記録膜を形成できるため に、生産性や生産コスト面で有利である。無機材料薄膜でが 1層のタイプとしては特 許文献 1に、 2層のタイプとしては特許文献 2などに開示されている。 [0007] In this respect, the hole punching method is advantageous in terms of productivity and production cost because a recording film can be formed with two or less inorganic material thin films. Patent Document 1 discloses a single-layer type inorganic material thin film, and Patent Document 2 discloses a two-layer type.
[0008] ただ、この穴開け方式は、記録感度が、前記無機材料薄膜の相変化や合金化によ り記録する方式に比して低いという問題があった。この局所的な記録マーク形成方式 は、記録膜である無機材料薄膜をレーザ光により溶融して、穴、ピットなどを開ける方 式である。このため、無機材料薄膜の融点以上にまで温度を上げる必要があり、必然 的に高いレーザパワーを必要とする。 However, this punching method has a problem that the recording sensitivity is lower than the recording method due to phase change or alloying of the inorganic material thin film. This local recording mark forming method is a method in which an inorganic material thin film as a recording film is melted with a laser beam to form holes, pits, and the like. For this reason, it is necessary to raise the temperature to above the melting point of the inorganic material thin film, and inevitably high laser power is required.
[0009] また、このように高いレーザパワーによると、無機材料薄膜を溶融させて、穴、ピット などを開けた部分に、溶融した膜が水滴のようになって残りやすくなる。この残った水 滴状の溶融膜が存在すると、記録マーク部分の反射率の変化を阻害して、信号の変 調度が上がらないという問題もあった。 [0009] Further, according to such a high laser power, the thin film of the inorganic material is melted, and the melted film tends to remain like water droplets in a portion where holes, pits, and the like are formed. The presence of the remaining droplet-like molten film hinders the change in reflectivity of the recording mark portion and prevents the signal modulation from increasing.
[0010] 局所的な記録マーク形成方式の、これらの問題を改善するために、従来から種々 の技術が提案されている。例えば、非特許文献 1には、融点および熱伝導率の低い Te薄膜を使用して、低いレーザパワーで記録マークの穴をあける技術が開示されて いる。 [0010] Various techniques have been proposed in the past to improve these problems of the local recording mark formation method. For example, Non-Patent Document 1 discloses a technique of using a Te thin film having a low melting point and low thermal conductivity to make a recording mark hole with low laser power.
[0011] 特許文献 3、 4には、基板上に A1を含む Cu基合金からなる反応層と、 Siなどを含む 反応層とが積層された光情報記録膜が開示されている。これらの文献に示された光 記録膜では、レーザ光の照射によって、基板上に、各反応層に含まれる元素が混合 された領域が部分的に形成され、それにより反射率が大きく変化することから、青色 レーザなどの短波長レーザを用いて高感度で記録できると記載されている。 Patent Documents 3 and 4 disclose optical information recording films in which a reaction layer made of a Cu-based alloy containing A1 and a reaction layer containing Si or the like are laminated on a substrate. In the optical recording films shown in these documents, the region where the elements contained in each reaction layer are mixed is partially formed on the substrate by the laser beam irradiation, and the reflectivity changes greatly. Therefore, it is described that recording can be performed with high sensitivity using a short wavelength laser such as a blue laser.
[0012] 特許文献 5、 6および 9は、記録マークによる信号 C/N比（carrier-to-noise ratio： キャリアとノイズの出力レベルの比）の低下を防止し、高い信号 C/Nと反射率とを備 えた光情報記録媒体を開示するもので、記録膜として Inを含む Cu基合金 (特許文献 5)、 Biなどを含む Ag基合金 (特許文献 6)、 Biなどを含む Sn基合金 (特許文献 9)が
記載されている。 [0012] Patent Documents 5, 6 and 9 prevent a decrease in signal C / N ratio (carrier-to-noise ratio) due to a recording mark, and a high signal C / N and reflection. An optical information recording medium having a high efficiency is disclosed, and a Cu-based alloy containing In as a recording film (Patent Document 5), an Ag-based alloy containing Bi (Patent Document 6), an Sn-based alloy containing Bi, etc. (Patent Document 9) Are listed.
[0013] 特許文献 7、 8は Sn基合金を用いた光情報記録媒体に関するもので、特許文献 7 には、合金層中に、熱処理工程で少なくとも一部が凝集し得る元素を 2種以上含有さ せた光情報記録媒体が開示されている。具体的には、 Biや Inを含む厚さ;!〜 8nm程 度の Sn- Cu基合金層からなり、高融点で熱伝導率の高い光情報記録媒体である。 [0013] Patent Documents 7 and 8 relate to an optical information recording medium using a Sn-based alloy. Patent Document 7 includes two or more elements that can be aggregated at least partially in the heat treatment step in the alloy layer. An optical information recording medium is disclosed. Specifically, it is an optical information recording medium having a high melting point and a high thermal conductivity, comprising a Sn—Cu based alloy layer having a thickness including Bi and In;
[0014] 特許文献 8には、記録特性に優れた Sn- Bi合金に、 Snや Biよりも酸化され易い被 酸化性物質を添加した光情報記録膜が開示されており、高温多湿環境下にお!/、て も優れた耐久性を示すことが強調されてレ、る。 [0014] Patent Document 8 discloses an optical information recording film in which an oxidizable substance that is easier to oxidize than Sn or Bi is added to an Sn-Bi alloy having excellent recording characteristics. It is emphasized that it shows excellent durability.
特許文献 1 : ：特開昭 52 - - 130304号公報 Patent Document 1:: JP-A 52-130304
特許文献 2 : ：特開昭 53 - - 31104号公幸 Patent Document 2:: Japanese Patent Publication No. 53-31104
特許文献 3 : ：特開 2004 — 5922号公幸 Patent Document 3:: JP 2004-5922 Noriyuki
特許文献 4 : ：特開 2004 — 234717号公報 Patent Document 4:: JP 2004-234717 A
特許文献 5 : ：特開 2002 — 172861号公報 Patent document 5:: JP 2002-172861 A
特許文献 6 : ：特開 2002 — 144730号公報 Patent Document 6:: JP 2002-144730 A
特許文献 7 : ：特開平 2— 117887号公報 Patent Document 7:: Japanese Patent Laid-Open No. 2-117887
特許文献 8 : ：特開 2001 — 180114号公報 Patent Document 8:: JP 2001-180114 A
特許文献 9 : ：特開 2002 — 225433号公報 Patent Document 9:: JP 2002-225433 A
非特許文献 l :Appl. Phys. Lett. 、 Vol. 34 (1979) p. 835 Non-patent literature l: Appl. Phys. Lett., Vol. 34 (1979) p. 835
発明の開示 Disclosure of the invention
[0015] 近年、記録情報の高密度化に対応するため、青紫色レーザなどの短波長レーザを 用いた光情報の記録と再生技術が開発されている。これに伴い、この技術に適合す る記録膜の特性として、下記（1)〜（4)などの諸特性が要求されている。 （1)高信号 C/N (読取り時の信号が強くバックグラウンドのノイズが小さレ、）、低ジッター (信号位 置のばらつきが少ない）などの高品質の信号書込み ·読取り。 （2)高記録感度（低パ ヮ一のレーザ光で書き込みができる）。 （3)記録膜からの高反射率。 （4)高耐食性。 In recent years, optical information recording and reproducing techniques using a short wavelength laser such as a blue-violet laser have been developed in order to cope with higher recording information density. Along with this, various characteristics such as the following (1) to (4) are required as characteristics of the recording film suitable for this technology. (1) High-quality signal writing / reading such as high signal C / N (high signal at reading and low background noise), low jitter (small variation in signal position). (2) High recording sensitivity (Writing is possible with a low-performance laser beam). (3) High reflectivity from the recording film. (4) High corrosion resistance.
[0016] しかし、前記した従来の記録マーク形成方式の金属系各記録膜では、要求される 上記諸特性の全てを兼備、あるいは十分に満たすことができず、実用化には難があ
[0017] 例えば、前記特開平 2— 117887号公報には、 55質量％11—40質量％31— 5質 i%Cu合金（原子％に換算すると、 53. 5原子％11 — 37. 7原子％31— 8. 8原子 %Cu合金)からなる膜厚 2〜4nmの光記録膜が開示されている。しかし、この光記録 膜組成では、実用可能なレベルの信号 C/N比は得られ難い。また、この特許文献 に開示されている合金層の厚さは 2〜4nmである力 上記合金組成にとっては、膜 厚が薄過ぎるため、実用化できるレベルの反射率は得られなかった。 [0016] However, the conventional recording mark forming metal-based recording films described above are difficult to put to practical use because they do not have all of the above-mentioned various characteristics or cannot sufficiently satisfy them. [0017] For example, Japanese Patent Laid-Open No. 2-117887 discloses 55 mass% 11-40 mass% 31-5 quality i% Cu alloy (in terms of atomic%, 53.5 atomic% 11-37.7 atoms % 31-8.8 atom% Cu alloy) is disclosed. However, with this optical recording film composition, it is difficult to obtain a practical signal C / N ratio. In addition, the thickness of the alloy layer disclosed in this patent document is 2 to 4 nm. For the above alloy composition, the film thickness is too thin, and thus a practically usable reflectance was not obtained.
[0018] また、特開 2001— 180114号公幸 には、 Sn— Bi合金に、この Snや Biよりも酸ィ匕さ れ易い被酸化性物質を加えた光記録膜が開示されている。ところ力 これらの合金で は、後述する本発明の Sn基合金記録膜を超えるレベルの信号 C/N比や記録感度 は得られなかった。 [0018] In addition, Japanese Patent Application Laid-Open No. 2001-180114 discloses an optical recording film in which an Sn-Bi alloy is added with an oxidizable substance that is more easily oxidized than Sn or Bi. However, with these alloys, a signal C / N ratio and recording sensitivity at levels exceeding those of the Sn-based alloy recording film of the present invention described later were not obtained.
[0019] 更に、特開 2002— 225433号公報には、合金組成が 84原子0 /0Sn— 10原子0 /0Z n— 6原子％313である Sn基合金製の光記録膜が開示されている。し力もこの Sn基合 金でも、後述する本発明の Sn基合金を超えるレベルの信号 C/N比や記録感度、 反射率は得られなかった。 [0019] Further, JP 2002- the 225,433 discloses, Sn based alloy of the optical recording layer alloy composition is 84 atomic 0/0 Sn- 10 atoms 0/0 Z n- 6 atomic% 313 discloses ing. However, neither the signal strength nor the Sn-base alloy provided a signal C / N ratio, recording sensitivity, or reflectivity that exceeded the level of the Sn-base alloy of the present invention described later.
[0020] しかし、金属系の記録膜は、前記した通り、有機系記録膜に較べて材料が著しく安 定であるという大きな利点がある。このため、金属系材料で上記要求諸特性を満足す る実用的な記録膜を開発することは、信頼性の高い光情報記録媒体である BD (Blu- ray Disc)— Rや、 HD DVD (Digital Versatile Disc)—Rをユーザに提供する上で 極めて重要となる。 However, the metal-based recording film has a great advantage that the material is remarkably stable as compared with the organic recording film, as described above. For this reason, the development of a practical recording film that satisfies the above-mentioned characteristics with metallic materials can be achieved by using BD (Blu-ray Disc) —R, HD DVD ( Digital Versatile Disc) —R is extremely important in providing users with R.
[0021] このため、本発明者らは、上記（1)〜（4)として示した要求諸特性を満たすとともに 、記録精度の信頼性が高ぐコスト的にも廉価な、次世代の青紫色レーザを用いた良 好な記録感度を持つ穴開け方式の記録膜として、低融点でかつ環境負荷の小さレ、1 n合金が適当であることを知見した。 [0021] For this reason, the present inventors have developed a next-generation blue-purple that satisfies the required characteristics shown in the above (1) to (4), has high recording accuracy, and is inexpensive in terms of cost. It was found that a 1n alloy having a low melting point and a low environmental load is suitable as a hole-drilling recording film with good recording sensitivity using a laser.
[0022] ただ、この In合金からなる記録膜 (光情報記録膜）は、良好な記録特性が得られる 一方で、記録感度（穴開け感度）が十分でないため、穴開け (記録）には比較的高い レーザパワーが必要であるという課題が明らかとなった。 [0022] However, the recording film (optical information recording film) made of the In alloy can provide good recording characteristics, but the recording sensitivity (drilling sensitivity) is not sufficient. The problem of the need for high laser power was clarified.
[0023] 本発明はこの様な事情に着目してなされたものであって、その目的は、比較的低い レーザパワーによって穴開け (記録）が可能となり、良好な記録特性を持ちつつ、さら
に良好な信号変調度が得られる記録膜を有する光情報記録媒体を提供することにあ [0023] The present invention has been made by paying attention to such a situation, and the object thereof is to enable drilling (recording) with a relatively low laser power, and while having good recording characteristics, It is an object of the present invention to provide an optical information recording medium having a recording film capable of obtaining a good signal modulation degree.
[0024] この目的を達成するための本発明に係る光情報記録媒体の要旨は、エネルギービ ームの照射により記録マークが形成される記録膜を有する光情報記録媒体であって 、この記録膜が In合金と酸化物との混合物からなることである。 [0024] The gist of the optical information recording medium according to the present invention for achieving this object is an optical information recording medium having a recording film on which a recording mark is formed by irradiation of an energy beam. Is composed of a mixture of In alloy and oxide.
[0025] 上記要旨において、好ましい態様は以下の通りである。前記光情報記録媒体の記 録膜における前記 In合金は、 Niおよび Coの一種または二種を 1〜65原子％含み、 残部 Inおよび不可避的不純物からなることが好ましい。また、この In合金の Niおよび Coの一種または二種の含有量が 50原子％以下であることが好ましい。また、この In 合金における Niおよび Coの一種または二種の含有量が 20原子％以上であることが 好ましい。また、これらの Niおよび Coを含む前記 In合金力 更に、 Sn、 Bi、 Geおよ び Siから選ばれる一種または二種以上を 19原子％以下（0原子％を含まない)含有 すること力 S好ましい。また、前記光情報記録媒体の記録膜における前記酸化物が、シ リコン、アルミニウムおよびニオブの各酸化物から選択される一種か、またはこれら二 種以上の複合酸化物であることが好ましい。また、前記光情報記録媒体の記録膜に おける In合金と酸化物との混合比率は、 In合金と酸化物との体積比である（In合金 体積） / (酸化物体積）で 3〜； 10の範囲であることが好まし!/、。 [0025] In the above summary, preferred embodiments are as follows. The In alloy in the recording film of the optical information recording medium preferably contains 1 to 65 atomic% of one or two kinds of Ni and Co, with the balance being In and inevitable impurities. Further, the content of one or two of Ni and Co in the In alloy is preferably 50 atomic% or less. Further, the content of one or two of Ni and Co in the In alloy is preferably 20 atomic% or more. In addition, the In alloying force containing Ni and Co, and further containing 19 atomic% or less (not including 0 atomic%) of one or more selected from Sn, Bi, Ge and Si S preferable. The oxide in the recording film of the optical information recording medium is preferably one kind selected from silicon, aluminum and niobium oxides, or a composite oxide of two or more kinds thereof. Further, the mixing ratio of the In alloy and the oxide in the recording film of the optical information recording medium is a volume ratio of the In alloy to the oxide (In alloy volume) / (oxide volume) of 3 to 10; Preferred to be in the range! / ,.
[0026] 本発明によれば、光情報記録媒体の記録膜を、 In合金と誘電体成分である酸化物 との混合物から構成することによって、これら混合物記録膜 (光情報記録膜)の熱伝 導率を制御し、レーザにより投入された熱の拡散を抑えて、エネルギーを効率的に用 いることが可能となる。 According to the present invention, the recording film of the optical information recording medium is composed of a mixture of an In alloy and an oxide that is a dielectric component, so that heat transfer of these mixture recording films (optical information recording film) is achieved. By controlling the conductivity and suppressing the diffusion of heat input by the laser, it becomes possible to use energy efficiently.
[0027] 後述する図 7の通り、 In合金と酸化物との混合物からなる記録膜は、 In合金のみで 形成されている記録膜に比べ、熱伝導率が大幅に低下する。これによつて、記録膜 におけるレーザにより投入された熱の拡散を抑えることができる。したがって、 In合金 と酸化物との混合物からなる記録膜は、より低いレーザパワーによって溶融でき、より 低いレーザパワーによって局所的な記録マーク（穴、ピットなど）の形成が可能となる 。この結果、良好な記録特性を持ちつつ、さらに良好な信号変調度が得られる記録 膜を得ること力でさる。
図面の簡単な説明 [0027] As shown in Fig. 7 described later, the thermal conductivity of a recording film made of a mixture of an In alloy and an oxide is significantly lower than that of a recording film formed only of an In alloy. As a result, the diffusion of heat input by the laser in the recording film can be suppressed. Therefore, a recording film made of a mixture of In alloy and oxide can be melted with a lower laser power, and local recording marks (holes, pits, etc.) can be formed with a lower laser power. As a result, it is possible to obtain a recording film that has a good recording characteristic and a better signal modulation degree. Brief Description of Drawings
[0028] [図 1]本発明光情報記録媒体の一実施形態を示す断面模式図である。 FIG. 1 is a schematic cross-sectional view showing an embodiment of the optical information recording medium of the present invention.
[図 2]本発明光情報記録媒体の他の実施形態を示す断面模式図である。 FIG. 2 is a schematic cross-sectional view showing another embodiment of the optical information recording medium of the present invention.
[図 3]本発明光情報記録媒体の他の実施形態を示す断面模式図である。 FIG. 3 is a schematic cross-sectional view showing another embodiment of the optical information recording medium of the present invention.
[図 4]本発明光情報記録媒体の他の実施形態を示す断面模式図である。 FIG. 4 is a schematic cross-sectional view showing another embodiment of the optical information recording medium of the present invention.
[図 5]実施例 1における、記録膜の記録レーザパワーと信号変調度の関係を示す説 明図である。 FIG. 5 is an explanatory diagram showing the relationship between the recording laser power of the recording film and the signal modulation degree in Example 1.
[図 6]実施例 1における、記録膜の記録レーザパワーと信号 C/N比の関係を示す説 明図である。 FIG. 6 is an explanatory diagram showing the relationship between the recording laser power of the recording film and the signal C / N ratio in Example 1.
[図 7]実施例 1における、記録膜の熱伝導率を測定した結果を示す説明図である。 FIG. 7 is an explanatory view showing the result of measuring the thermal conductivity of the recording film in Example 1.
[図 8]実施例 2における、記録膜の記録レーザパワーと信号変調度の関係を示す説 明図である。 FIG. 8 is an explanatory diagram showing the relationship between the recording laser power of the recording film and the signal modulation degree in Example 2.
[図 9]実施例 2における、記録膜の記録レーザパワーと信号 C/N比の関係を示す説 明図である。 FIG. 9 is an explanatory diagram showing the relationship between the recording laser power of the recording film and the signal C / N ratio in Example 2.
[図 10]実施例 3における、記録膜の記録レーザパワーと信号変調度の関係を示す説 明図である。 FIG. 10 is an explanatory diagram showing the relationship between the recording laser power of the recording film and the signal modulation degree in Example 3.
[図 11]実施例 3における、記録膜の記録レーザパワーと信号 C/N比の関係を示す 説明図である。 FIG. 11 is an explanatory diagram showing the relationship between the recording laser power of the recording film and the signal C / N ratio in Example 3.
符号の説明 Explanation of symbols
[0029] 1 :支持基板、 2 :光学調整層、 3、 5 :誘電体層、 4 :記録膜、 [0029] 1: support substrate, 2: optical adjustment layer, 3, 5: dielectric layer, 4: recording film,
6 :光透過層、 7A、 7B :記録膜群、 8 :中間層、 9 :接着剤層、 6: Light transmission layer, 7A, 7B: Recording film group, 8: Intermediate layer, 9: Adhesive layer,
10 :光ディスク 10: Optical disc
発明を実施するための最良の形態 BEST MODE FOR CARRYING OUT THE INVENTION
[0030] (光情報記録媒体の全体構成） [0030] (Overall configuration of optical information recording medium)
以下に図面を用いて、前提としての、本発明光情報記録媒体 (光ディスク)全体構 成の実施形態を例示する。図;!〜 4は、波長が約 350〜700nmのレーザ光などのェ ネルギービームを記録膜に照射し、データの記録と再生を行うことのできる追記型の 本発明光情報記録媒体を例示する断面模式図である。尚、図 1、図 2の (A)、図 3の
(B)および図 4の（B)、（D)は記録場所が凸状に形成されたもの、図 1、図 2の（B)、 図 3の (A)および図 4の (A)、 (C)は記録場所が凹状に形成されたものを例示してい An embodiment of the entire configuration of the optical information recording medium (optical disc) of the present invention as a premise will be exemplified below with reference to the drawings. FIGS.! To 4 exemplify a write-once type optical information recording medium of the present invention capable of recording and reproducing data by irradiating a recording film with an energy beam such as a laser beam having a wavelength of about 350 to 700 nm. It is a cross-sectional schematic diagram. In Fig. 1 and Fig. 2, (A) and Fig. 3 (B) and (B) and (D) in FIG. 4 are those in which the recording location is formed in a convex shape, FIG. 1, (B) in FIG. 2, (A) in FIG. 3 and (A) in FIG. (C) shows an example in which the recording location is concave.
[0031] 図 1の光ディスク 10は、支持基板 1と、光学調整層 2と、誘電体層 3、 5と、誘電体層 [0031] An optical disc 10 in FIG. 1 includes a support substrate 1, an optical adjustment layer 2, dielectric layers 3 and 5, and a dielectric layer.
3と 5の間に挟まれた記録膜 4と、光透過層 6とを備えている。 A recording film 4 sandwiched between 3 and 5 and a light transmission layer 6 are provided.
[0032] 図 2の光ディスク 10は、支持基板 1と、第 0記録膜群 (光学調整層、誘電体層、記録 膜を備えた一群の層） 7Aと、中間層 8と、第 1記録膜群 (光学調整層、誘電体層、記 録膜を備えた一群の層） 7Bと、光透過層 6とを備えている。 [0032] The optical disk 10 in FIG. 2 includes a support substrate 1, a 0th recording film group (a group of layers including an optical adjustment layer, a dielectric layer, and a recording film) 7A, an intermediate layer 8, and a first recording film. A group (a group of layers including an optical adjustment layer, a dielectric layer, and a recording film) 7B and a light transmission layer 6 are provided.
[0033] 図 3は、 1層 DVD— R、 1層 DVD + R、 1層 HD DVD— Rタイプの光ディスクを例 示し、図 4は、 2層 DVD- R、 2層 DVD + R、 2層 HD DVD— Rタイプの光ディスクを 例示する。符号 8は中間層、符号 9は接着剤層を示している。 [0033] Fig. 3 shows an example of a single-layer DVD-R, single-layer DVD + R, single-layer HD DVD-R type optical disc, and Fig. 4 shows a double-layer DVD-R, dual-layer DVD + R, double-layer. HD DVD—Example of R type optical disc. Reference numeral 8 denotes an intermediate layer, and reference numeral 9 denotes an adhesive layer.
[0034] 図 2、 4における第 0および第 1の記録膜群 7A、 7Bを構成する一群の層は、 3層構 造や、 2層構造の他、記録膜 1層のみからなるものであっても構わない。例えば、 3層 構造は、図の上側から、誘電体層/記録膜/誘電体層、誘電体層/記録膜/光学 調整層、記録膜/誘電体層/光学調整層などで構成される。また、 2層構造は、図 の上側から、記録膜/誘電体層、誘電体層/記録膜、記録膜/光学調整層、光学 調整層/記録膜などで構成される。 [0034] The group of layers constituting the 0th and 1st recording film groups 7A and 7B in Figs. 2 and 4 consist of only one recording film in addition to the three-layer structure or the two-layer structure. It doesn't matter. For example, the three-layer structure is composed of a dielectric layer / recording film / dielectric layer, a dielectric layer / recording film / optical adjustment layer, a recording film / dielectric layer / optical adjustment layer, etc. from the upper side of the figure. The two-layer structure is composed of a recording film / dielectric layer, a dielectric layer / recording film, a recording film / optical adjustment layer, an optical adjustment layer / recording film, and the like from the upper side of the figure.
[0035] (記録膜組成） [0035] (Recording film composition)
以上のような光情報記録媒体の構成を前提として、本発明光情報記録媒体では、 記録膜 4を In合金と SiOなどの酸化物との混合物からなるものとし、後述する通り、記 録情報の高密度化を可能にすることを特徴とする。 On the premise of the configuration of the optical information recording medium as described above, in the optical information recording medium of the present invention, the recording film 4 is made of a mixture of an In alloy and an oxide such as SiO. It is characterized by enabling high density.
[0036] 本発明光情報記録媒体では、この In合金と酸化物との混合物からなる記録膜 4に 隣接して誘電体層 3、 5を選択的に有する。これら誘電体層 3、 5を設ける場合は、 SiThe optical information recording medium of the present invention selectively has dielectric layers 3 and 5 adjacent to the recording film 4 made of a mixture of this In alloy and oxide. When these dielectric layers 3 and 5 are provided, Si
、 Mg、 Ta、 Zr、 Mn、 Inなどから選択される元素の酸化物を主成分とすることが好ま しい。 It is preferable that the main component is an oxide of an element selected from Mg, Ta, Zr, Mn, In and the like.
[0037] これらの酸化物からなる誘電体層 3、 5は、誘電体機能と共に、レーザパワーでの局 所的な記録マークの形成の際の、 In合金と酸化物との混合物からなる記録膜 4のぬ れ性を制御する。これによつて、レーザパワーでの局所的な記録マークの形成の際
の、前記した水滴状の溶融 Inの溶け残りや固まりとしての Inの偏在を抑制して、局所 的な記録マークの形成を良好とする。これによつて、信号の変調度の低下を防止す る。また、これらの酸化物からなる誘電体層は、誘電体層として、記録膜 4を保護し、 反射率や信号 C/N比も高める誘電体機能（効果)も有している。 [0037] The dielectric layers 3 and 5 made of these oxides have a dielectric film and a recording film made of a mixture of an In alloy and an oxide when forming a local recording mark with laser power. Control the wettability of 4. This makes it possible to form local recording marks with laser power. In this way, it is possible to suppress the uneven distribution of the molten In in the form of water droplets and the uneven distribution of In as a mass, and to improve the formation of local recording marks. This prevents a decrease in signal modulation. Further, the dielectric layer made of these oxides also has a dielectric function (effect) that protects the recording film 4 and increases the reflectance and the signal C / N ratio as the dielectric layer.
[0038] 誘電体層 3、 5は、上記したように、その記録膜のぬれ性制御や誘電体機能を発揮 させるためには、 In合金と酸化物との混合物からなる記録膜 4に隣接させる。この内、 誘電体層 3は記録膜 4と基板 1との間に位置することが好ましい。また、誘電体層 5は 記録膜 4と光透過層 6との間に位置することが好ましい。 [0038] As described above, the dielectric layers 3 and 5 are adjacent to the recording film 4 made of a mixture of In alloy and oxide in order to control the wettability of the recording film and perform the dielectric function. . Of these, the dielectric layer 3 is preferably located between the recording film 4 and the substrate 1. The dielectric layer 5 is preferably located between the recording film 4 and the light transmission layer 6.
[0039] (In合金） [0039] (In alloy)
本発明光情報記録媒体では、記録膜 4を In合金と SiOなどの酸化物との混合物か らなるものとする力 S、先ず、 In合金の組成につき以下に説明する。 In the optical information recording medium of the present invention, the force S for forming the recording film 4 from a mixture of an In alloy and an oxide such as SiO, first, the composition of the In alloy will be described below.
[0040] 純 Inの融点は 156. 6°Cの低融点であり、融点が 660°Cの Al、 962°Cの Ag、 1085 °Cの Cuに比しても著しく低融点である。このため、 Inは、低レーザパワーのより低温 でも溶融、変形でき、上記局所的な記録マーク（穴、ピットなど）の形成性が良ぐマ 一キング性が良くなる可能性がある。 [0040] The melting point of pure In is a low melting point of 156.6 ° C, which is significantly lower than that of Al at 660 ° C, Ag at 962 ° C, and Cu at 1085 ° C. For this reason, In can be melted and deformed even at a lower temperature with low laser power, and there is a possibility that the above-mentioned local recording marks (holes, pits, etc.) can be formed with good marking performance.
[0041] ただ、純 Inでは、上記融点があまりに低過ぎ、レーザ照射による上記局所的な記録 マークの際に、レーザを照射していない周囲の記録膜も溶融させてしまい、結果とし てマーキング性が悪くなる可能性が高い。また、形成された記録膜の表面粗さが粗く なって、反射率、感度ゃ耐環境性が低いという欠点もある。 [0041] However, in pure In, the melting point is too low, and the surrounding recording film not irradiated with the laser is melted at the time of the local recording mark by laser irradiation. Is likely to get worse. In addition, the surface roughness of the formed recording film becomes rough, and there is a disadvantage that the reflectance and sensitivity are low in environmental resistance.
[0042] Ni、Co : [0042] Ni, Co:
これに対して、純 Inに、 Niおよび Coの一種または二種を含有させ、 In合金化する ことによって、 In合金としての融点が適度に上がって最適化され、マーキング性が向 上する。この際、 In合金の組成としては、 Niおよび Coの一種または二種を 1〜65原 子％含み、残部 Inおよび不可避的不純物からなることが好ましい。ここで、前記 Niお よび Coの一種または二種の含有量の上限を 50原子％とすることが好ましい。また、 前記 Niおよび Coの一種または二種の含有量の下限を 20原子％とすることが好まし い。即ち、 Niおよび Coの一種または二種の含有量の範囲は、上記;!〜 65原子％の 範囲に対して、 1〜50原子％の狭い範囲または 20〜65原子％の狭い範囲とし、更
には 20〜50原子％のより狭い範囲とすることが好ましい。これら好ましい Niおよび C oの一種または二種の含有量においても、 In合金の組成としては、残部 Inおよび不 可避的不純物からなるものとする。 On the other hand, by adding one or two kinds of Ni and Co to pure In and forming an In alloy, the melting point as the In alloy is appropriately increased and optimized, and the marking property is improved. At this time, the composition of the In alloy preferably includes 1 to 65 atomic percent of one or two of Ni and Co, and the balance is In and unavoidable impurities. Here, the upper limit of the content of one or two of Ni and Co is preferably 50 atomic%. Further, the lower limit of the content of one or two of Ni and Co is preferably 20 atomic%. That is, the content range of one or two of Ni and Co is set to a narrow range of 1 to 50 atomic percent or a narrow range of 20 to 65 atomic percent with respect to the range of! Is preferably in a narrower range of 20 to 50 atomic%. Even in the preferable content of one or two of Ni and Co, the composition of the In alloy is composed of the balance In and unavoidable impurities.
[0043] このような効果を有する周期律表の第 8属の元素としては、 Niおよび Co以外に、 Fe 、 Ru、 Rh、 Pd、 Os、 Ir、 Ni、 Co、 Ptなどが例示される。ただ、これらの元素よりも、 Ni および Coの効果が著しく大きい。なお、上記 Fe、 Ru、 Rh、 Pd、 Os、 Ir、 Ptなどを（不 可避的）不純物として含むことは許容される。 [0043] Examples of elements belonging to Group 8 of the periodic table having such effects include Fe, Ru, Rh, Pd, Os, Ir, Ni, Co, and Pt in addition to Ni and Co. However, the effects of Ni and Co are significantly greater than these elements. In addition, it is allowed to contain the above-mentioned Fe, Ru, Rh, Pd, Os, Ir, Pt, etc. as (unavoidable) impurities.
[0044] Niおよび Coの一種または二種の合計含有量が上記した範囲から外れて少な過ぎ ると、純 Inと同様に、形成された記録膜の表面粗さが粗くなつて、反射率、感度ゃ耐 環境性が低くなる。一方、 Niおよび Coの一種または二種の合計含有量が上記した 範囲から外れて多すぎると、 Niおよび Co元素の融点が高いために、 In合金記録膜 の融点が高くなり、低レーザパワーによるマーキング性が低下し、 In合金を採用する 意味が無くなる。 [0044] If the total content of one or two of Ni and Co is out of the above range and is too small, the surface roughness of the formed recording film becomes rough as in pure In, and the reflectance, Sensitivity decreases environmental resistance. On the other hand, if the total content of one or two of Ni and Co is out of the above range and is too large, the melting point of the Ni and Co elements is high, so the melting point of the In alloy recording film is high, and the low laser power causes Marking performance is reduced, and it makes no sense to use In alloy.
[0045] Sn、 Bi、Ge、 Si : [0045] Sn, Bi, Ge, Si:
さらに、 In合金の組成としては、上記のように Inに Niおよび Coの一種または二種を 含有させた上で、更に、 Sn、 Bi、 Geおよび Siの一種または二種以上を 19原子％以 下（0原子％を含まない）含有させることができる。これら Sn、 Bi、 Geおよび Siを、 Ni および Coに加えて含有させることによって、ジッター値をより低減することが出来る。 このメカニズムは必ずしも明らかではないが、 Sn、 Bi、 Geおよび Siは、融点を上げず に低熱伝導率化による横方向の熱の滲み抑制を実現していると推察される。この際、 In合金の組成としては、 Niおよび Coの一種または二種を 1〜65原子％含み、更に、 Sn、 Bi、 Geおよび Siの一種または二種以上を 19原子％以下（0原子％を含まない） 含有し、残部 Inおよび不可避的不純物からなるものとする。この際、これら Niおよび Coの一種または二種の含有量を、上記各好ましい範囲に、より狭くしても良い。 Further, the composition of the In alloy is that, as described above, In contains one or two kinds of Ni and Co, and further contains one or more kinds of Sn, Bi, Ge and Si at 19 atomic% or less. Lower (not including 0 atomic%) can be included. By including these Sn, Bi, Ge and Si in addition to Ni and Co, the jitter value can be further reduced. Although this mechanism is not necessarily clear, it is presumed that Sn, Bi, Ge, and Si achieve lateral heat bleed suppression by lowering the thermal conductivity without increasing the melting point. In this case, the composition of the In alloy includes 1 to 65 atomic% of one or two kinds of Ni and Co, and further 19 atomic% or less (0 atomic%) of one or more kinds of Sn, Bi, Ge and Si. Contained, and the remainder shall consist of In and inevitable impurities. At this time, the content of one or two of these Ni and Co may be made narrower within the above preferred ranges.
[0046] (記録膜混合物組成） [0046] (Recording film mixture composition)
本発明の光情報記録媒体では、このような In合金と酸化物との混合物から、記録膜 4を構成する。 In合金と酸化物とを混合することによって、記録膜 4の熱伝導率が制 御され、酸化物を混合せず、 In合金のみとした記録膜 4の場合に比して、レーザによ
り投入された熱の拡散を抑えて、エネルギーをより効率的に用いることが可能となる。 In the optical information recording medium of the present invention, the recording film 4 is composed of such a mixture of In alloy and oxide. By mixing the In alloy and the oxide, the thermal conductivity of the recording film 4 is controlled. Compared to the recording film 4 in which the oxide is not mixed and only the In alloy is used, the laser is used. This makes it possible to use the energy more efficiently by suppressing the diffusion of the input heat.
[0047] この酸化物は、前記誘電体層 3、 5として誘電体層成分として汎用されている、シリ コン、アルミニウムおよびニオブの各酸化物から選択される一種力、、またはこれら二種 以上の複合酸化物であることが好ましい。即ち、 SiO、 Al O、 NbO、 NbO、 Nb O などから選択される酸化物の 1種（単独）、または 2種以上 (複数）の複合酸化物から なるものであることが好ましい。因みに、誘電体層成分として用いられる酸化物は、こ れら以外にも、 Mg、 Ta、 Zr、 Mn、 Inなどから選択される元素の酸化物があり、使用 可能である。ただ、この中でも、 In合金と混合されて、 In合金膜の熱伝導率を下げ、 また、誘電体層 3、 5の機能を合わせ有する記録膜 4とする効果が高いのは、シリコン 、アルミニウムおよびニオブの酸化物である。 [0047] This oxide is one kind of force selected from silicon, aluminum and niobium oxides, or two or more kinds of these widely used as dielectric layer components as the dielectric layers 3 and 5. A composite oxide is preferable. That is, the oxide is preferably composed of one (single) oxide selected from SiO, Al 2 O, NbO, NbO, Nb 2 O, or the like, or two or more (plural) complex oxides. Incidentally, oxides used as the dielectric layer component include oxides of elements selected from Mg, Ta, Zr, Mn, In, and the like, which can be used. However, among these, it is mixed with In alloy to lower the thermal conductivity of the In alloy film, and the recording film 4 having the functions of the dielectric layers 3 and 5 is highly effective for silicon, aluminum and aluminum. Niobium oxide.
[0048] 本発明は、 In合金に対して SiOなどの酸化物を混合すると、この混合物の記録膜 4 の熱伝導率は、 In合金単独の場合に比して、低くなる。このため、レーザにより投入さ れた熱の拡散を抑えて、局所的な記録マーク形成のためのエネルギーを効率的に 用いること力 Sできる。この結果、 In合金のみとした記録膜 4の場合に比して、より低い レーザパワーによって、 In合金と誘電体成分である酸化物との混合物が溶融でき、 局所的な記録マーク形成が可能となる。この結果、 In合金のみとした記録膜 4の場合 に比して、良好な記録特性を持ちつつ、信号変調度がさらに良好な記録膜を得るこ と力 Sできる。 In the present invention, when an oxide such as SiO is mixed with the In alloy, the thermal conductivity of the recording film 4 of this mixture becomes lower than that of the In alloy alone. For this reason, it is possible to suppress the diffusion of the heat input by the laser and to efficiently use the energy for forming the local recording mark. As a result, compared to the case of the recording film 4 made only of the In alloy, the mixture of the In alloy and the oxide that is a dielectric component can be melted by a lower laser power, and local recording marks can be formed. Become. As a result, it is possible to obtain a recording film having better recording characteristics and a better signal modulation degree than that of the recording film 4 made of only In alloy.
[0049] 即ち、 In合金に酸化物を混合した、両者の混合物からなる記録膜 4は、低レーザパ ヮ一のより低温でも溶融、変形できるが、レーザを照射していない周囲の記録膜は溶 融させない、適正な融点とすることができる。そして、この効果を、マーキングに使用 される 810nm〜405nmの各波長のレーザ光の低レーザパワーマーキングで発揮で きる。また、記録膜の表面粗さが小さく抑えられ、後述する記録膜の膜厚の範囲で、 高反射率や高感度、高耐環境性が得られると!/、う特徴がある。 That is, the recording film 4 made of a mixture of In alloy mixed with an oxide can be melted and deformed even at a lower temperature than the low laser performance, but the surrounding recording film not irradiated with the laser is dissolved. An appropriate melting point can be obtained without melting. This effect can be exhibited by low laser power marking of laser light of each wavelength of 810 nm to 405 nm used for marking. In addition, the surface roughness of the recording film can be kept small, and high reflectivity, high sensitivity, and high environmental resistance can be obtained within the range of the film thickness of the recording film described later.
[0050] 言い換えると、 In合金と酸化物との混合物からなる記録膜 4とすることによって、誘 電体層 3、 5と記録膜 4とを混合した記録膜 4を形成したとも言える。この結果、誘電体 層 3、 5の機能を合わせ有する記録膜 4を形成したとも言える。このため、青紫色レー ザなどの短波長レーザを用いた光情報の記録と再生技術に適合し、記録情報の高
密度化を可能にし、保証できる。具体的には、前記した、（1)高信号 C/N比、低ジッ ターなどの高品質の信号書込み'読取り、（2)高記録感度の他に、（3)記録膜からの 高反射率、（4)高耐食性、などを可能にできる。更に、記録精度の信頼性が高ぐコ スト的にも廉価とし、実用的な記録膜とできる。 In other words, it can be said that by forming the recording film 4 made of a mixture of an In alloy and an oxide, the recording film 4 in which the dielectric layers 3 and 5 and the recording film 4 are mixed is formed. As a result, it can be said that the recording film 4 having the functions of the dielectric layers 3 and 5 is formed. For this reason, it is compatible with optical information recording and reproduction technology using short-wavelength lasers such as blue-violet lasers. Allows densification and guarantees. Specifically, (1) high-quality signal writing / reading such as (1) high signal C / N ratio and low jitter, (2) in addition to high recording sensitivity, (3) high reflection from recording film Rate, (4) high corrosion resistance, etc. can be made possible. Further, the recording accuracy is high and the cost is low, and a practical recording film can be obtained.
[0051] これらの効果を得るためには、記録膜 4における In合金と SiOなどの酸化物との混 合比率を (In合金に対する酸化物の混合比率を）、 In合金と酸化物との体積比であ る（In合金体積) / (酸化物体積）で 3〜； 10の範囲とすることが好まし!/、。 [0051] In order to obtain these effects, the mixing ratio of the In alloy and the oxide such as SiO in the recording film 4 (the mixing ratio of the oxide to the In alloy) is determined, and the volume of the In alloy and the oxide is determined. The ratio (In alloy volume) / (oxide volume) is preferably 3 to 10;
[0052] 酸化物の混合比率が前記体積比で 10を超えて大きくなつた場合には、記録膜 4中 の酸化物の混合量が少なすぎて、上記した熱伝導率を小さくする効果がなくなる。こ のため、 In合金単独の記録膜 4の場合と大差なくなり、良好な記録特性を持ちつつ、 さらに良好な信号変調度が得られる記録膜を得ることができなくなる。 [0052] When the mixing ratio of the oxide exceeds 10 in the volume ratio, the mixing amount of the oxide in the recording film 4 is too small, and the effect of reducing the above-described thermal conductivity is lost. . For this reason, there is no great difference from the case of the recording film 4 made of the In alloy alone, and it becomes impossible to obtain a recording film that has good recording characteristics and a better signal modulation.
[0053] 一方、酸化物の混合比率が前記体積比で 3未満と小さくなつた場合には、記録膜 4 中の酸化物の混合量が多すぎて、記録膜 4の熱伝導率が小さくなりすぎる。このため 、却って、局所的な記録マーク形成に必要なレーザパワーが高くなり、信号品質が低 下する。これは、酸化物の混合比率が大きくなつた場合には、記録膜 4全体に対する 酸化物の寄与が大きくなりすぎるため、記録メカニズムが In合金記録膜 4の溶融-穴 開け方式ではなくなり（変化してしまい）、結果として良好な信号品質 (信号 C/N比） が得られな!/、からであると推考される。 [0053] On the other hand, when the mixing ratio of the oxide is reduced to less than 3 in the volume ratio, the amount of oxide mixed in the recording film 4 is too large, and the thermal conductivity of the recording film 4 decreases. Too much. For this reason, on the contrary, the laser power required for local recording mark formation increases, and the signal quality decreases. This is because when the oxide mixing ratio increases, the contribution of the oxide to the entire recording film 4 becomes too large, so the recording mechanism is no longer the melt-drilling method of the In alloy recording film 4 (changes). As a result, good signal quality (signal C / N ratio) cannot be obtained!
[0054] (記録膜厚み） [0054] (Recording film thickness)
上記 In合金と酸化物との混合物からなる記録膜 4は、安定した精度で確実な記録 膜を形成する上で、光情報記録媒体の構造にもよるが、厚さを l〜50nmの範囲にす るのがよい。この厚み範囲の In合金と酸化物との混合物からなる記録膜 4は、特に波 長が 350〜700nmの範囲のレーザ光に対して高い記録感度を示し、優れた光情報 の書込み ·読取り精度を発揮する光情報記録媒体となる。 The recording film 4 made of a mixture of the In alloy and the oxide has a thickness in the range of 1 to 50 nm, depending on the structure of the optical information recording medium, in order to form a reliable recording film with stable accuracy. It is good to do. The recording film 4 consisting of a mixture of In alloy and oxide in this thickness range shows high recording sensitivity, especially for laser light with a wavelength in the range of 350 to 700 nm, and excellent optical information writing / reading accuracy. It becomes an optical information recording medium to be exhibited.
[0055] 記録膜の厚みが lnm未満では、光記録膜が薄過ぎるため、仮に光記録膜の上部 や下部に光学調整層や誘電体層を設けたとしても、光記録膜の膜面にポアなどの欠 陥が生じ易くなつて、満足の!/、く記録感度が得られ難くなる。 [0055] If the thickness of the recording film is less than 1 nm, the optical recording film is too thin. Therefore, even if an optical adjustment layer or a dielectric layer is provided above or below the optical recording film, a pore is formed on the film surface of the optical recording film. If defects such as these are likely to occur, it will be difficult to obtain satisfactory recording sensitivity.
[0056] 逆に 50nmを超えて厚くなり過ぎると、レーザ光照射によって与えられる熱が記録膜
内で急速に拡散し易くなり、記録マークの形成が困難になる。 [0056] On the other hand, if the thickness exceeds 50 nm and becomes too thick, the heat given by the laser beam irradiation is changed to the recording film. It becomes easy to diffuse rapidly in the inside, and it becomes difficult to form a recording mark.
[0057] 光ディスクとしての反射率の観点からすると、記録膜のより好ましい厚さは、誘電体 層や光学調整層を設けない場合、 8nm以上、 30nm以下、更に好ましくは 12nm以 上、 20nm以下であり、誘電体層や光学調整層を設ける場合は、 3nm以上、 30nm 以下、更に好ましくは 5nm以上、 20nm以下である。 [0057] From the viewpoint of reflectivity as an optical disc, the more preferable thickness of the recording film is 8 nm or more and 30 nm or less, more preferably 12 nm or more and 20 nm or less when no dielectric layer or optical adjustment layer is provided. In the case where a dielectric layer or an optical adjustment layer is provided, the thickness is 3 nm or more and 30 nm or less, more preferably 5 nm or more and 20 nm or less.
[0058] (誘電体層） [0058] (Dielectric layer)
上記した通り、本発明の In合金と酸化物との混合物からなる記録膜 4は、誘電体層 3、 5と記録膜 4とを混合した記録膜 4を形成したとも言え、誘電体層 3、 5の機能を合 わせ有する記録膜 4を形成したとも言える。このため、誘電体層 3、 5を敢えて設けな い態様も可能である。 As described above, it can be said that the recording film 4 made of the mixture of In alloy and oxide of the present invention formed the recording film 4 in which the dielectric layers 3 and 5 and the recording film 4 were mixed. It can be said that the recording film 4 having the function of 5 was formed. Therefore, a mode in which the dielectric layers 3 and 5 are not provided is possible.
[0059] これに対して、誘電体層 3、 5を選択的に設ける場合には、 Si、 Al、 Nb、 Mg、 Ta、 Z r、 Mnおよび Inから選択される、特定元素の酸化物からなる誘電体層 3、 5を設けるこ とが好ましい。これら好適な酸化物としては、 SiO、 Al O、 NbO、 NbO、 Nb O、 M gO、 Ta O、 ZrO、 MnO、 InOなどが例示される。 [0059] On the other hand, when the dielectric layers 3 and 5 are selectively provided, an oxide of a specific element selected from Si, Al, Nb, Mg, Ta, Zr, Mn, and In is used. The dielectric layers 3 and 5 are preferably provided. Examples of these suitable oxides include SiO, Al 2 O, NbO, NbO, Nb 2 O, MgO, Ta 2 O, ZrO, MnO, and InO.
[0060] これら元素の酸化物からなる誘電体層 3、 5は、前記した通り、レーザパワーでの局 所的な記録マークの形成の際の In基合金記録膜 4のぬれ性を制御し、信号の変調 度の低下を抑制する。また、誘電体層 3、 5は、誘電体層として、記録膜 4を保護し、こ れにより記録情報の保存期間を大幅に延長する（耐久性が向上する）他、反射率や 信号 C/N比も高める効果も有してレ、る。 [0060] As described above, the dielectric layers 3 and 5 made of oxides of these elements control the wettability of the In-based alloy recording film 4 when a local recording mark is formed with laser power. Reduces signal modulation. In addition, the dielectric layers 3 and 5 protect the recording film 4 as a dielectric layer, thereby greatly extending the storage period of recorded information (improves durability), and reflectivity and signal C / It also has the effect of increasing the N ratio.
[0061] なお、これら元素の酸化物からなる誘電体層 3、 5は、誘電体層がこれら元素の酸 化物のみからならずとも、誘電体層の成膜上、誘電体層の本発明効果を阻害しない 範囲で、これら元素の酸化物以外の酸化物などを誘電体層に不純物として含むこと を許容する。勿論、可能であれば、これら元素の酸化物のみから実質的になる誘電 体層を成膜しても良い。 [0061] It should be noted that the dielectric layers 3 and 5 made of oxides of these elements have the effect of the present invention of the dielectric layers on the formation of the dielectric layers, even if the dielectric layers are not only made of oxides of these elements. In the range that does not inhibit the above, it is allowed to contain oxides other than the oxides of these elements as impurities in the dielectric layer. Of course, if possible, a dielectric layer consisting essentially of oxides of these elements may be formed.
[0062] (誘電体層厚み） [0062] (Dielectric layer thickness)
これら誘電体層 3、 5の厚みは、上記信号変調度の低下抑制効果を発揮するため に、光情報記録媒体の構造にもよる力 厚さを好ましくは 5〜200nmの範囲、より好 ましくは 10〜； 150nmの範囲にする。 5nm未満では誘電体層の厚みが薄過ぎるため
、誘電体層を設けたとしても、上記効果が発揮されない。一方、厚くし過ぎても効果は 向上せず、厚過ぎると、却って光情報記録媒体の生産性が低下する等の不利益が 生じてくるため、 200nmを超えて厚くする必要は無い。 The thickness of these dielectric layers 3 and 5 is preferably in the range of 5 to 200 nm, depending on the structure of the optical information recording medium, in order to exert the effect of suppressing the decrease in the signal modulation. Is in the range of 10 to 150 nm. If the thickness is less than 5 nm, the dielectric layer is too thin. Even if a dielectric layer is provided, the above effect is not exhibited. On the other hand, if it is too thick, the effect is not improved. If it is too thick, there is a disadvantage that the productivity of the optical information recording medium is reduced. Therefore, it is not necessary to increase the thickness beyond 200 nm.
[0063] この特定元素の酸化物層の形成手段も特に制限されないが、スパッタリング法が好 まし!/ヽ方法として例示される。 [0063] The means for forming the oxide layer of the specific element is not particularly limited, but the sputtering method is preferable!
[0064] (光情報記録媒体としての好まし!/、条件や構造） [0064] (preferred as an optical information recording medium! /, Conditions and structure)
以下に、本発明光情報記録媒体の、光情報記録媒体としての他の好ましい条件や 構造、製造方法について説明する。 Hereinafter, other preferable conditions, structure and manufacturing method of the optical information recording medium of the present invention as an optical information recording medium will be described.
[0065] 支持基板などの素材： [0065] Materials such as support substrate:
本発明の代表的な実施形態となる光ディスクは、上記記録膜 4以外の、また、上記 特定元素の酸化物層を用いない場合には、この誘電体層 3、 5を含めて、支持基板 1 や光学調整層 2などの素材は特に限定されず、通常使用されているものを適宜選択 して使用できる。 The optical disk as a representative embodiment of the present invention includes the dielectric layers 3 and 5 including the dielectric layers 3 and 5 in the case where the oxide layer of the specific element other than the recording film 4 is not used. The materials such as the optical adjustment layer 2 and the like are not particularly limited, and those usually used can be appropriately selected and used.
[0066] 支持基板の素材としては、汎用されている、ポリカーボネート樹脂（PC基板とも言う )、ノルボルネン系樹脂、環状ォレフィン系共重合体、非晶質ポリオレフインなどが好 適に用いられる。光学調整層の素材としては、 Ag、 Au、 Cu、 Al、 Ni、 Cr、 Ti等やそ れらの合金などが好適に用いられる。 [0066] As the material for the support substrate, generally used polycarbonate resin (also referred to as PC substrate), norbornene-based resin, cyclic olefin-based copolymer, amorphous polyolefin and the like are preferably used. As a material for the optical adjustment layer, Ag, Au, Cu, Al, Ni, Cr, Ti, or an alloy thereof is preferably used.
[0067] レーザ光波長： [0067] Laser light wavelength:
記録のために照射するレーザ光の好ましい波長は 350〜700nmの範囲であり、 35 Onm未満では、カバー層（光透過層）などによる光吸収が顕著となり、光記録膜への 書込み ·読み出しが困難になる。逆に波長が 700nmを超えて過大になると、レーザ 光のエネルギーが低下するため、光記録膜への記録マークの形成が困難になる。こ うした観点から、情報の記録に用いるレーザ光線のより好ましい波長は 350nm以上 、 660腹以下、更に好ましくは 380腹以上、 650應以下である。 The preferred wavelength of the laser beam irradiated for recording is in the range of 350 to 700 nm. If it is less than 35 Onm, light absorption by the cover layer (light transmission layer) becomes significant, making it difficult to write to and read from the optical recording film. become. Conversely, if the wavelength exceeds 700 nm and becomes excessive, the energy of the laser beam is reduced, making it difficult to form a recording mark on the optical recording film. From this point of view, the more preferable wavelength of the laser beam used for recording information is 350 nm or more and 660 or less, more preferably 380 or more and 650 or less.
[0068] スパッタリング： [0068] Sputtering:
上記記録膜や誘電体層を形成するために用いる、スパッタリングの際のスパッタリン グターゲットの組成は、上記した記録膜や誘電体層の、所望の合金組成や酸化物組 成と基本的に同一のものが使用できる。言い換えると、スパッタリングターゲットの組
成を上記した記録膜や誘電体層の合金組成や酸化物組成と同一とすることにより、 スパッタリングによって成膜される記録膜や誘電体層を、所望の合金組成や酸化物 組成に成膜することができる。 The composition of the sputtering target used for forming the recording film or dielectric layer is basically the same as the desired alloy composition or oxide composition of the recording film or dielectric layer described above. Can be used. In other words, a set of sputtering targets By making the composition the same as the alloy composition and oxide composition of the recording film and dielectric layer described above, the recording film and dielectric layer formed by sputtering are formed into a desired alloy composition and oxide composition. be able to.
[0069] 例えば、本発明の In合金と酸化物との混合物からなる記録膜は、別々の In合金タ 一ゲットと SiOなどの酸化物ターゲットとを各々用いて、前記した記録膜の所定混合 割合となるように、スパッタ条件を制御して各々同時スパッタする（コスパッタリング）、 DCスパッタリング法や RFスパッタリング法などによって形成する。 [0069] For example, the recording film made of the mixture of the In alloy and the oxide of the present invention uses a separate In alloy target and an oxide target such as SiO, respectively, and a predetermined mixing ratio of the recording film described above. In this way, the sputtering conditions are controlled so that each is sputtered simultaneously (co-sputtering), and DC sputtering or RF sputtering is used.
[0070] また、 In合金中に SiOなどの酸化物を、前記した記録膜の所定混合割合で予め混 合した単一のスパッタリングターゲットを作製しておき、これを DCスパッタリング法や R Fスパッタリング法によってスパッタして、本発明の記録膜を形成することができる。 [0070] Also, a single sputtering target was prepared by previously mixing an oxide such as SiO in the In alloy at a predetermined mixing ratio of the recording film described above, and this was performed by DC sputtering or RF sputtering. The recording film of the present invention can be formed by sputtering.
[0071] これらの、いずれのスパッタリング法によっても、 In合金と酸化物とが均一に分散混 合して、混合物の膜質が均質化した、本発明記録膜が成膜できる。 [0071] By any of these sputtering methods, the recording film of the present invention can be formed in which the In alloy and the oxide are uniformly dispersed and mixed, and the film quality of the mixture is homogenized.
[0072] このスパッタリングターゲットの製造に当っては、雰囲気中のガス成分（窒素、酸素 など)や溶解炉成分が微量ながら不純物としてスパッタリングターゲットに混入するこ と力 Sある。しかし、本発明の記録膜やスパッタリングターゲットの成分組成は、これら不 可避的に混入してくる微量成分までも規定するものではなぐ本発明の上記特性が 阻害されない限り、それら不可避不純物の微量の混入は許容される。 [0072] In the production of this sputtering target, there is a force S that gas components (nitrogen, oxygen, etc.) and melting furnace components in the atmosphere are mixed in the sputtering target as impurities even though they are in trace amounts. However, the component composition of the recording film and sputtering target of the present invention does not define even these inevitable trace components, so long as the above characteristics of the present invention are not hindered, the trace amounts of these inevitable impurities are not. Mixing is allowed.
[0073] 以下、実施例を挙げて本発明をより具体的に説明するが、下記実施例はもとより本 発明を制限する性質のものではなく、前 ·後記本発明の趣旨を逸脱しな!/、範囲で適 宜変更を加えて実施することも可能であり、それらは本発明の技術的範囲に包含さ れる。 [0073] Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples and should not depart from the spirit of the present invention described above and below! However, the present invention can be carried out with appropriate modifications within the scope, and these are included in the technical scope of the present invention.
実施例 Example
[0074] (実施例 1) [Example 1]
In合金と、酸化物である SiOとの混合物からなる各記録膜の信号変調度、信号 C /N比を測定、評価した。具体的には、図 1に示すタイプの光ディスク 10を試作して 、支持基板 1上に記録膜 4、その上に光透過層 6とを、順に 2層を設け、このディスク の信号読み取り時の信号変調度、信号 C/N比を測定、評価した。この結果を図 5、 6に示す。また、 In合金と、酸化物である SiOとの混合物からなる各記録膜の熱伝導
率を測定した。この結果を図 7に示す。なお、図 5、 6において、菱形印を結ぶ線が発 明例 1、四角印を結ぶ線が発明例 2、三角印を結ぶ線が比較例 1、 X印を結ぶ線が 比較例 2である。 The signal modulation degree and signal C / N ratio of each recording film made of a mixture of In alloy and oxide SiO were measured and evaluated. Specifically, an optical disk 10 of the type shown in FIG. 1 is prototyped, and a recording film 4 and a light transmission layer 6 are provided on the support substrate 1 in this order, and two layers are provided in that order. Signal modulation and signal C / N ratio were measured and evaluated. The results are shown in Figs. The thermal conductivity of each recording film consisting of a mixture of In alloy and oxide SiO The rate was measured. The result is shown in FIG. 5 and 6, the line connecting the diamond marks is Invention Example 1, the line connecting the square marks is Invention Example 2, the line connecting the triangle marks is Comparative Example 1, and the line connecting the X marks is Comparative Example 2. .
[0075] 図 5、 6、 7における発明例 1、 2は、後述する通り、 In合金と SiOとの適当量の混合 物からなる記録膜を有する。また、比較例 1は In合金のみからなる記録膜であり、比 較例 2は SiOの混合量が多すぎる記録膜である。これら図 5、 6の通り、 In合金と SiO との適当量の混合物からなる記録膜を有する発明例 1、 2は、前記比較例 1や比較 例 2に比して、 8mW程度のレーザパワーは勿論、 5mW程度のより低いレーザパワー でも、信号変調度や信号 C/N比が高い。また、図 7の通り、 In合金と SiOとの混合 物からなる記録膜である発明例 1及び発明例 2は、 In合金のみで形成されて!/、る比 較例 1の記録膜に比べ、熱伝導率が大幅に低下することが裏付けられる。 Inventive Examples 1 and 2 in FIGS. 5, 6 and 7 have a recording film made of an appropriate amount of a mixture of In alloy and SiO, as will be described later. Further, Comparative Example 1 is a recording film made of only an In alloy, and Comparative Example 2 is a recording film in which the amount of SiO mixed is too large. As shown in FIGS. 5 and 6, Invention Examples 1 and 2 having a recording film made of an appropriate amount of a mixture of In alloy and SiO have a laser power of about 8 mW compared to Comparative Example 1 and Comparative Example 2. Of course, even with a lower laser power of around 5 mW, the signal modulation and signal C / N ratio are high. In addition, as shown in FIG. 7, Invention Example 1 and Invention Example 2, which are recording films made of a mixture of In alloy and SiO, are formed only of In alloy! /, Compared with the recording film of Comparative Example 1. This confirms that the thermal conductivity is greatly reduced.
[0076] これら発明例 1、 2や比較例 1、 2の光ディスクの作製法を以下に各々示す力 光デ イスクの積層構造として、支持基板 1表面上に直接設けた記録膜 4と、その記録膜 4 の上に直接光透過層 6を設け、光学調整層 2や誘電体層 3、 5は設けなかった。 [0076] A recording film 4 directly provided on the surface of the support substrate 1 as a laminated structure of the magneto-optical disk shown below for the production methods of the optical disks of Invention Examples 1 and 2 and Comparative Examples 1 and 2, respectively, and the recording thereof The light transmission layer 6 was directly provided on the film 4, and the optical adjustment layer 2 and the dielectric layers 3 and 5 were not provided.
[0077] 発明例 1 : [0077] Invention Example 1:
図 1に示すディスク基板 1として、ポリカーボネート基板 (厚さ 1. lmm、トラックピッチ 0. 32 111、、溝幅 0. 16 111、、溝深さ 25nm)を用いた。その基板表面に、厚さ 12nm 相当の In— 25at%Niの In合金をコスパッタリングを用いた DCスパッタリング法によ つて成膜すると同時に、 RFスパッタリング法によって厚さ 1. 5nm相当の SiOを成膜 した。そして、 In合金/ SiO誘電体の混合比率が体積比にて 8 : 1となる総膜厚 13. 5nmの記録膜 4を成膜した。なお、本実施例において、成膜に用いた各ターゲット組 成や、成膜した各記録膜の膜組成は、 ICP発光分析法または ICP質量分析法で測 定した。 As the disk substrate 1 shown in FIG. 1, a polycarbonate substrate (thickness 1. lmm, track pitch 0.32 111, groove width 0.116 111, groove depth 25 nm) was used. On the substrate surface, an In—25at% Ni In alloy with a thickness of 12 nm was formed by DC sputtering using co-sputtering, and at the same time, SiO equivalent to 1.5 nm was formed by RF sputtering. did. Then, a recording film 4 having a total film thickness of 13.5 nm was formed so that the mixing ratio of In alloy / SiO dielectric was 8: 1 by volume. In this example, the composition of each target used for film formation and the film composition of each recording film formed were measured by ICP emission spectrometry or ICP mass spectrometry.
[0078] 記録層 4形成のためのスパッタリング条件は、到達真空度： 10— 5Torr以下（lTorr = 133. 3Pa)、 Arガス圧： lmTorr、 DCスパッタ成膜パワー及び RFスパッタ成膜パ ヮ一はそれぞれ 50W及び 45Wとして、成膜レート比が DC : RF = 8 : 1となる様に設 定した。 [0078] The sputtering conditions for the recording layer 4 formed, ultimate vacuum: 10- 5 Torr or less (lTorr = 133. 3Pa), Ar gas pressure: lmTorr, DC sputtering power and RF sputtering deposition path Wa one Were set to 50 W and 45 W, respectively, so that the deposition rate ratio was DC: RF = 8: 1.
[0079] 次!/、で、記録膜 4の上に、紫外線硬化性樹脂（日本化薬社製、商品名：「BRD— 1
30」 )をスピンコートした後、紫外線硬化させて膜厚 100 ± 15 mの光透過層 6を形 成した。 [0079] Next! /, On the recording film 4, an ultraviolet curable resin (manufactured by Nippon Kayaku Co., Ltd., trade name: "BRD-1" 30 ”) was spin-coated, and then cured by UV to form a light transmission layer 6 having a thickness of 100 ± 15 m.
[0080] 発明例 2: [0080] Invention Example 2:
発明例 2は、上記発明例 1と同じ（条件の）ポリカーボネート基板を用いた。その基 板表面に、発明例 1と同じぐ厚さ 12nm相当の In— 25at%Niの In合金をコスパッタ リングを用いた DCスパッタリング法によって成膜すると同時に、発明例 1と同様に RF スパッタリング法によって厚さ 3nm相当の SiOを成膜した。そして、 In合金/ SiO誘 電体の混合比率が前記体積比にて 4となる総膜厚 15nmの記録膜 4を成膜した。 Inventive Example 2 used the same (condition) polycarbonate substrate as Inventive Example 1. On the substrate surface, an In-25at% Ni In alloy equivalent to 12 nm in thickness equivalent to that of Invention Example 1 was formed by DC sputtering using co-sputtering, and at the same time by RF sputtering as in Invention Example 1. A SiO film having a thickness of 3 nm was formed. Then, a recording film 4 having a total film thickness of 15 nm was formed such that the mixing ratio of In alloy / SiO 2 dielectric material was 4 in the volume ratio.
[0081] 記録膜 4形成のためのスパッタリング条件は、到達真空度： 10— 5TOTr以下、 Arガス 圧： lmTorr、 DCスパッタ成膜パワー及び RFスパッタ成膜パワーはそれぞれ 50W 及び 90Wとして、成膜レート比が DC : RF = 4 : 1となる様に設定した。次いで、記録 膜 4の上に、発明例 1と同じ光透過層 6を形成した。 [0081] The sputtering conditions for the recording layer 4 formed, ultimate vacuum: 10- 5 T OT r less, Ar gas pressure: as LmTorr, DC sputtering power and RF sputtering, respectively deposition power is 50W and 90W, The film formation rate ratio was set to be DC: RF = 4: 1. Next, the same light transmission layer 6 as that of Invention Example 1 was formed on the recording film 4.
[0082] 比較例 1 : [0082] Comparative Example 1:
比較例 1は、発明例 1と同じ（条件の）ポリカーボネート基板を用いた。その基板表 面に、発明例 1と同じく DCスパッタリング法によって厚さ 12nm相当の In— 25at%Ni の In合金のみの記録膜 4を成膜した。 Comparative Example 1 used the same (condition) polycarbonate substrate as Invention Example 1. On the substrate surface, a recording film 4 made of only an In-25 at% Ni alloy equivalent to a thickness of 12 nm was formed by DC sputtering as in Invention Example 1.
[0083] 記録層 4形成のためのスパッタリング条件は、到達真空度： 10— 5Torr以下、 Arガス 圧： lmTorr、スパッタ成膜パワーは 50Wとした。次いで、記録膜 4の上に、発明例 1 と同じ光透過層 6を形成した。 [0083] The sputtering conditions for the recording layer 4 formed, ultimate vacuum: 10- 5 Torr or less, Ar gas pressure: LmTorr, sputtering power was 50 W. Next, the same light transmission layer 6 as that of Invention Example 1 was formed on the recording film 4.
[0084] 比較例 2 : [0084] Comparative Example 2:
比較例 2は、発明例 1と同じ（条件の）ポリカーボネート基板を用いた。その基板表 面に、発明例 1と同じぐ厚さ 12nm相当の In— 25at%Niの In合金をコスパッタリン グを用いた DCスパッタリング法によって成膜すると同時に、発明例 1と同様に RFスパ ッタリング法によって厚さ 6nm相当の SiOを成膜した。そして、 In合金/ SiO誘電体 の混合比率が体積比にて 2： 1となる総膜厚 18nmの記録膜 4を成膜した。 In Comparative Example 2, the same polycarbonate substrate (under the same conditions) as in Invention Example 1 was used. On the substrate surface, an In-25at% Ni In alloy equivalent to 12nm in thickness equivalent to that of Invention Example 1 was deposited by DC sputtering using co-sputtering. At the same time, RF sputtering method was used as in Invention Example 1. Thus, a SiO film having a thickness of 6 nm was formed. Then, a recording film 4 having a total film thickness of 18 nm was formed so that the mixing ratio of In alloy / SiO dielectric was 2: 1 by volume.
[0085] 記録膜 4形成のためのスパッタリング条件は、到達真空度： 10— 5Torr以下、 Arガス 圧： lmTorr、 DCスパッタ成膜パワー及び RFスパッタ成膜パワーはそれぞれ 50W 及び 180Wとして、成膜レート比が DC : RF = 2 : 1となる様に設定した。次いで、記録
膜 4の上に、発明例 1と同じ光透過層 6を形成した。 [0085] The sputtering conditions for the recording layer 4 formed, ultimate vacuum: 10- 5 Torr or less, Ar gas pressure: LmTorr, as each DC sputtering power and RF sputtering power 50W and 180 W, film formation The rate ratio was set to DC: RF = 2: 1. Then record On the film 4, the same light transmission layer 6 as that in Invention Example 1 was formed.
[0086] 図 5の光ディスクの信号変調度評価： [0086] Evaluation of signal modulation degree of optical disk in FIG. 5:
図 5には、発明例 1、 2及び比較例 1、 2、それぞれの光記録媒体における記録レー ザパワーと信号変調度の関係を各々示してレ、る。 FIG. 5 shows the relationship between the recording laser power and the signal modulation degree in each of the optical recording media of Invention Examples 1 and 2 and Comparative Examples 1 and 2, respectively.
[0087] この測定は、光ディスク評価装置 (パルステック工業社製「ODU-1000」（商品名）、 記録レーザ波長： 405nm、 NA (開口数）： 0.85)とデジタルオシロスコープ（横河電機社 製、商品名「DL1640L」）を使用し、信号変調度を測定した。より具体的には、レーザ パワー 4mWから 12mWの範囲において線速 4. 9m/sで長さ 0. 60 111の記録マ ークを繰り返して形成し、レーザパワー 0. 3mWにおける信号読み取り時の信号変調 度を測定した。 [0087] This measurement was performed using an optical disk evaluation device (ODU-1000 (trade name) manufactured by Pulstec Industrial Co., Ltd., recording laser wavelength: 405 nm, NA (numerical aperture): 0.85) and a digital oscilloscope (manufactured by Yokogawa Electric Corporation, Using the product name “DL1640L”), the degree of signal modulation was measured. More specifically, a recording mark of 0.660 111 in length was repeatedly formed at a linear velocity of 4.9 m / s in the range of laser power 4 mW to 12 mW, and the signal at the time of signal reading at laser power 0.3 mW The degree of modulation was measured.
[0088] なお、信号変調度とは、得られた信号の (信号強度 max—信号強度 min) / (信号 強度 max) 100 (単位％)のことであり、所望の記録特性を得るためには信号変調 度が 50%以上必要であると一般的に考えられている。 [0088] The signal modulation degree means (signal intensity max—signal intensity min) / (signal intensity max) 100 (unit%) of the obtained signal. In order to obtain desired recording characteristics, It is generally considered that a signal modulation degree of 50% or more is required.
[0089] 図 6の光ディスクの信号 C/N比評価： [0089] Evaluation of signal C / N ratio of optical disc in FIG. 6:
図 6には、発明例 1、 2及び比較例 1、 2、それぞれの光記録媒体における記録レー ザパワーと信号の C/N比の関係を各々示して!/、る。 FIG. 6 shows the relationship between the recording laser power and the signal C / N ratio in each of the optical recording media of Invention Examples 1 and 2 and Comparative Examples 1 and 2, respectively.
[0090] この測定は、図 5の光ディスクの信号変調度測定と同時に、光ディスク評価装置（同 上）とスペクトラムアナライザー（アドバンテスト社製、商品名「R3131A」）を使用して、 信号 C/N比（単位 dB)を測定した。より具体的には、レーザパワー 4mWから 12mW の範囲において線速 4. 9m/sで長さ 0. 60 mの記録マークを繰り返して形成し、 レーザパワー 0. 3mWにおける信号読み取り時の 4. 12MHz周波数成分の信号強 度をキャリア（単位 dB)とし、その前後の周波数成分の信号強度のノイズ (単位 dB)と した場合の比である、信号 C/N比（単位 dB)を測定した。 [0090] In this measurement, the signal C / N ratio was measured using an optical disk evaluation apparatus (same as above) and a spectrum analyzer (trade name “R3131A”) at the same time as the signal modulation degree measurement of the optical disk in FIG. (Unit: dB) was measured. More specifically, a recording mark with a length of 0.60 m is repeatedly formed at a linear speed of 4.9 m / s in the range of laser power 4 mW to 12 mW, and 4.12 MHz when reading a signal with a laser power of 0.3 mW. The signal C / N ratio (unit: dB), which is the ratio when the signal strength of the frequency component is the carrier (unit: dB) and the noise of the signal strength of the frequency component before and after that (unit: dB), was measured.
[0091] なお、所望の記録特性を得るためには、光ディスクの同信号の C/N比は、少なくと も 45dB以上は必要であると考えられて!/、る。 [0091] In order to obtain the desired recording characteristics, it is considered that the C / N ratio of the same signal of the optical disc needs to be at least 45 dB! /.
[0092] 図 5、 6の詳細な評価結果： [0092] Detailed evaluation results for Figures 5 and 6:
図 5、 6から、 In合金のみで形成されている記録膜とした比較例 1では記録に必要な レーザパワー、すなわち信号変調度が 50%以上かつ信号 C/N比が 45dB以上に
なるレーザパワーが 7〜8mW必要である。これに対し、 In合金と SiOとの混合物から なる記録膜である発明例 1及び発明例 2においては、レーザパワーが 6mW以下で、 信号変調度 50%以上かつ信号 C/N比 45dB以上になっていることが分かる。即ち 、 In合金/ SiO混合記録膜とすることにより、記録感度を大幅に改善することが可能 となることが裏付けられる。 From Figs. 5 and 6, in Comparative Example 1 where the recording film is formed only of In alloy, the laser power necessary for recording, that is, the signal modulation degree is 50% or more and the signal C / N ratio is 45 dB or more. The required laser power is 7-8mW. In contrast, in Invention Examples 1 and 2, which are recording films made of a mixture of In alloy and SiO, the laser power is 6 mW or less, the signal modulation degree is 50% or more, and the signal C / N ratio is 45 dB or more. I understand that That is, it is proved that the recording sensitivity can be greatly improved by using an In alloy / SiO mixed recording film.
[0093] また、図 5、 6から、 In合金に対する SiOの混合比率が、 In合金体積/酸化物体積 の体積比にて 2と高すぎる比較例 2においては、信号変調度に関しては良好な特性 を示す一方、信号 C/N比に関しては、全ての記録パワーにおいて 45dB以下にとど まっていた。この結果から、 In合金に対する SiOの混合比率をある一定 以上にし た場合、却って信号品質が低下するという悪影響があることが裏付けられる。このた め、 In合金に対する SiOの混合比率は、 In合金と酸化物との体積比である（In合金 体積) / (酸化物体積）で 3〜； 10の範囲が適当である。 [0093] Also, from Figs. 5 and 6, the mixing ratio of SiO to the In alloy is too high at 2 in the volume ratio of In alloy volume / oxide volume. On the other hand, the signal C / N ratio remained below 45 dB for all recording powers. This result confirms that when the mixing ratio of SiO to the In alloy is set to a certain level or more, there is an adverse effect that the signal quality is deteriorated. Therefore, the mixing ratio of SiO to In alloy is suitably in the range of 3 to 10 in terms of the volume ratio of In alloy to oxide (In alloy volume) / (oxide volume).
[0094] 図 7の熱伝導率評価： [0094] Thermal conductivity evaluation of FIG. 7:
図 7の、発明例 1、 2及び比較例 1の熱伝導率測定結果は、各記録膜の電気伝導率 を 4端子法から測定し、それを次式 1のヴィーデマン 'フランツ則に基づき、熱伝導率 に換算したィ直を用いた。 The thermal conductivity measurement results of Invention Examples 1 and 2 and Comparative Example 1 in FIG. 7 show that the electrical conductivity of each recording film was measured from the 4-terminal method, and this was calculated based on the Wiedemann's Franz law of the following equation 1. A straight line converted to conductivity was used.
Κ/ σ =LT (式 1)、但し、 K :熱伝導率 (W/m.K)、 σ：電気伝導率（S/m)、 L：口 一レンツ数（2. 45 X 10— 8W Ω /K2)、 T：絶対温度（K)を各々示す。 Κ / σ = LT (Equation 1), where, K: thermal conductivity (W / mK), σ: electric conductivity (S / m), L: mouth one Lenz number (2. 45 X 10- 8 W Ω / K 2 ), T: Absolute temperature (K), respectively.
[0095] この図 7の通り、 In合金と SiOとの混合物からなる記録膜である発明例 1及び発明 例 2は、 In合金のみで形成されている比較例 1の記録膜に比べ、熱伝導率が大幅に 低下することが裏付けられる。これによつて、 In合金と SiOとの混合物からなる記録 膜は、レーザにより投入された熱の拡散を抑えることができ、より低いレーザパワーに よって局所的な記録マークの形成が可能となる。この結果、上記した通り、良好な記 録特性を持ちつつ、さらに良好な信号変調度が得られる記録膜を得る効果があるこ と力 S裏付けられる。 [0095] As shown in Fig. 7, Invention Example 1 and Invention Example 2, which are recording films made of a mixture of In alloy and SiO, have a thermal conductivity as compared with the recording film of Comparative Example 1 formed only of In alloy. This confirms that the rate will decline significantly. As a result, the recording film made of a mixture of In alloy and SiO can suppress the diffusion of heat input by the laser, and a local recording mark can be formed with a lower laser power. As a result, as described above, it is proved that there is an effect of obtaining a recording film that has a good recording characteristic and can obtain a better signal modulation degree.
[0096] (実施例 2) [Example 2]
In合金と、酸化物である Al O、 Nb Oとの混合物からなる記録膜の信号変調度、 信号 C/N比を測定、評価した。具体的には、実施例 1と同じぐ図 1に示すタイプの
光ディスク 10を模擬して、支持基板 1上に記録膜 4、その上に光透過層 6と、順に 2層 を設け、このディスクの信号読み取り時の信号変調度、信号 C/N比を測定、評価し た。 The signal modulation degree and signal C / N ratio of a recording film made of a mixture of an In alloy and oxides of Al 2 O and Nb 2 O were measured and evaluated. Specifically, the type shown in Fig. 1 is the same as in Example 1. Simulating the optical disc 10, the recording film 4 on the support substrate 1 and the light transmission layer 6 on it are provided in this order, and the signal modulation degree and signal C / N ratio at the time of reading the signal of this disc are measured. evaluated.
[0097] この結果として、図 8、 9に示す通り、本発明の In合金と Al Oとの適当量の混合物 力 なる記録膜を有する発明例 3、 In合金と Nb Oとの適当量の混合物からなる記録 膜を有する発明例 4とは、 In合金のみからなる記録膜の比較例 1 (実施例 1と同じ）に 比して、信号変調度や信号 C/N比が優れて!/、た。 As a result, as shown in FIGS. 8 and 9, Invention Example 3 having an appropriate amount of mixture of In alloy and Al 2 O of the present invention, and an appropriate amount of mixture of In alloy and Nb 2 O Inventive example 4 having a recording film made of is superior in signal modulation degree and signal C / N ratio to Comparative Example 1 (same as Example 1) of a recording film made only of In alloy! /, It was.
[0098] 図 8、 9において、菱形印を結ぶ線が再度掲載する（実施例 1と同じ)発明例 2、四 角印を結ぶ線が発明例 3、三角印を結ぶ線が発明例 4、 X印を結ぶ線が比較例 1で ある。 [0098] In Figs. 8 and 9, the line connecting the diamond marks is again shown (same as in Example 1), Invention Example 2, the line connecting the square marks is Invention Example 3, the line connecting the triangle marks is Invention Example 4, The line connecting the X marks is Comparative Example 1.
[0099] これら発明例 3、 4の光ディスクの作製法を以下に各々示す力 光ディスクの積層構 造は実施例 1と同一にし、光学調整層 2や誘電体層 3、 5は設けなかった。 [0099] The forces shown in the following optical disc production methods of Invention Examples 3 and 4 were as follows. The laminated structure of the optical disc was the same as in Example 1, and the optical adjustment layer 2 and the dielectric layers 3 and 5 were not provided.
[0100] 発明例 3 : [0100] Invention Example 3:
発明例 1と同じ（条件の）ポリカーボネート基板を用いた。その基板表面に、発明例 1と同じく、厚さ 12nm相当の In— 25at %Niの In合金をコスパッタリングを用レ、た DC スパッタリング法によって成膜すると同時に、 RFスパッタリング法によって厚さ 3nm相 当の Al Oを成膜した。そして、 In合金/ Al O誘電体の混合比率が前記体積比に て 4となる総膜厚 15nmの記録膜 4を成膜した。 The same (condition) polycarbonate substrate as in Invention Example 1 was used. As in Invention Example 1, an In-25 at% Ni In alloy equivalent to a thickness of 12 nm was formed on the surface of the substrate by DC sputtering using co-sputtering, and at the same time, equivalent to 3 nm in thickness by RF sputtering. A film of AlO was formed. Then, a recording film 4 having a total film thickness of 15 nm was formed so that the mixing ratio of In alloy / Al 2 O dielectric was 4 in the volume ratio.
[0101] 記録層 4形成の発明例 1と同じためのスパッタリング条件は、到達真空度： 10— 5Torr 以下（lTorr= 133. 3Pa)、 Arガス圧： lmTorr、 DCスパッタ成膜パワー及び RFス パッタ成膜パワーはそれぞれ 50W及び 100Wとして、成膜レート比が DC : RF = 4 : 1 となる様に設定した。次いで、記録膜 4の上に、紫外線硬化性樹脂（日本化薬社製、 商品名：「BRD— 130」）をスピンコートした後、紫外線硬化させて、発明例 1と同じ膜 厚 100 ± 15 mの光透過層 6を形成した。 [0101] The sputtering conditions of the same for invention example 1 of the recording layer 4 formed, ultimate vacuum: 10- 5 Torr or less (lTorr = 133. 3Pa), Ar gas pressure: lmTorr, DC sputtering power and RF scan The deposition power was set to 50 W and 100 W, respectively, so that the deposition rate ratio was DC: RF = 4: 1. Next, an ultraviolet curable resin (manufactured by Nippon Kayaku Co., Ltd., trade name: “BRD-130”) is spin-coated on the recording film 4 and then cured by ultraviolet curing, and the same film thickness as in Invention Example 1 100 ± 15 m light-transmitting layer 6 was formed.
[0102] 発明例 4 : [0102] Invention Example 4:
発明例 1と同じ（条件の）ポリカーボネート基板を用いた。その基板表面に、発明例 1と同じく、厚さ 12nm相当の In— 25at%Niの In合金を、コスパッタリングを用いた D Cスパッタリング法によって成膜すると同時に、発明例 1と同様に RFスパッタリング法
によって厚さ 3nm相当の Nb Oを成膜した。そして、 In合金/ Nb O誘電体の混合 比率が前記体積比にて 4となる総膜厚 15nmの記録膜 4を成膜した。 The same (condition) polycarbonate substrate as in Invention Example 1 was used. On the substrate surface, as in Invention Example 1, an In-25at% Ni In alloy equivalent to a thickness of 12 nm was formed by DC sputtering using co-sputtering. As a result, a NbO film having a thickness of 3 nm was formed. Then, a recording film 4 having a total film thickness of 15 nm was formed such that the mixing ratio of In alloy / Nb 2 O dielectric was 4 in the volume ratio.
[0103] 記録膜 4形成のためのスパッタリング条件は、到達真空度： 10— 5TOTr以下、 Arガス 圧： lmTorr、 DCスパッタ成膜パワー及び RFスパッタ成膜パワーはそれぞれ 50W 及び 40Wとして、成膜レート比が DC : RF = 4 : 1となる様に設定した。次いで、記録 膜 4の上に、発明例 1と同じ光透過層 6を形成した。 [0103] The sputtering conditions for the recording layer 4 formed, ultimate vacuum: 10- 5 T OT r less, Ar gas pressure: as LmTorr, each DC sputtering power and RF sputtering power 50W and 40W, The film formation rate ratio was set to be DC: RF = 4: 1. Next, the same light transmission layer 6 as that of Invention Example 1 was formed on the recording film 4.
[0104] これら発明例 3、 4の光ディスクの信号変調度評価と、光ディスクの信号 C/N比評 価とは実施例 1と同じ条件で行った。 [0104] The signal modulation degree evaluation of the optical discs of Examples 3 and 4 and the signal C / N ratio evaluation of the optical disc were performed under the same conditions as in Example 1.
[0105] 図 8、 9の詳細な評価結果： [0105] Detailed evaluation results for Figures 8 and 9:
図 8、 9から、 In合金と、 Al Oまたは Nb Oとの混合物からなる記録膜である発明 例 3及び発明例 4においては、レーザパワーが 6mW以下で、信号変調度 50%以上 、かつ信号 C/N比 45dB以上になっていることが分かる。即ち、 In合金/ Al Oまた は Nb O混合記録膜とすることにより、 In合金のみの比較例 1に比して、記録感度を 大幅に改善することが可能となることが裏付けられる。 8 and 9, in Invention Example 3 and Invention Example 4, which are recording films made of a mixture of In alloy and Al 2 O or Nb 2 O, the laser power is 6 mW or less, the signal modulation degree is 50% or more, and the signal It can be seen that the C / N ratio is 45 dB or more. That is, it is supported that the recording sensitivity can be greatly improved by using an In alloy / Al 2 O or Nb 2 O mixed recording film as compared with Comparative Example 1 in which only the In alloy is used.
[0106] 以上の SiO、 Al O、 Nb Oの酸化物を用いた実施例 1、 2の結果は、他のニオブ 酸化物である NbO、 NbOや、 MgO、 Ta O、 ZrO、 MnO、 InOなどの他の酸化物 でも同様に得られると推考される。 [0106] The results of Examples 1 and 2 using the above oxides of SiO, Al 2 O, and Nb 2 O were NbO, NbO, other niobium oxides, MgO, Ta 2 O 3, ZrO, MnO, InO, etc. It is assumed that other oxides can be obtained in the same way.
[0107] (実施例 3) [Example 3]
実施例 1、 2とは異なる組成の In合金に対する酸化物の添加効果を評価した。具体 的には、実施例 1、 2と同じく、図 1に示すタイプの光ディスク 10を模擬して、支持基 板 1上に記録膜 4、その上に光透過層 6と、順に 2層を設け、このディスクの信号読み 取り時の信号変調度、信号 C/N比を測定、評価した。この結果を図 10、 11に示す The effect of adding an oxide to an In alloy having a composition different from those in Examples 1 and 2 was evaluated. Specifically, in the same manner as in Examples 1 and 2, the optical disk 10 of the type shown in FIG. 1 is simulated, and a recording film 4 is provided on the support substrate 1 and a light transmission layer 6 is provided on the support film 1 in this order. The signal modulation degree and signal C / N ratio at the time of signal reading of this disk were measured and evaluated. The results are shown in Figs.
〇 Yes
[0108] (評価結果） [0108] (Evaluation result)
発明例 5及び比較例 3、それぞれの光記録媒体における記録レーザパワーと信号 変調度との関係を図 10に、記録レーザパワーと信号の C/N比との関係を図 11に、 各々示す。これら図 10、 11において、黒丸印を結ぶ線が発明例 5、 *印を結ぶ線が 比較例 3である。
[0109] これら図 10、 11から、 In合金のみで形成されている記録膜とした比較例 3では、記 録に必要なレーザパワー、すなわち信号変調度が 50%以上かつ信号 C/N比が 45 dB以上になるレーザパワーが 7mW必要である。これに対し、 In合金と SiOとの混合 物からなる記録膜である発明例 5においては、レーザパワーが 6mW以下で、信号変 調度が 50%以上かつ信号 C/N比が 45dB以上になっていることが分かる。 Inventive Example 5 and Comparative Example 3, FIG. 10 shows the relationship between the recording laser power and the signal modulation degree in each optical recording medium, and FIG. 11 shows the relationship between the recording laser power and the signal C / N ratio. In FIGS. 10 and 11, the line connecting the black circles is Invention Example 5, and the line connecting the * marks is Comparative Example 3. From these FIGS. 10 and 11, in Comparative Example 3 in which the recording film is formed only of the In alloy, the laser power necessary for recording, that is, the signal modulation degree is 50% or more and the signal C / N ratio is A laser power of 45 m or more is required. In contrast, in Invention Example 5, which is a recording film made of a mixture of In alloy and SiO, the laser power is 6 mW or less, the signal modulation is 50% or more, and the signal C / N ratio is 45 dB or more. I understand that.
[0110] 即ち、本発明のように、 In合金/ SiO混合記録膜とすることにより、記録感度を大 幅に改善することが可能となることが裏付けられる。この様に、 In合金の組成が異な つても、本発明組成範囲内であれば、発明例は、 In合金のみからなる記録膜の比較 例に比して、 8mW程度のレーザパワーは勿論、 5mW程度のより低いレーザパワー でも、信号変調度や信号 C/N比が高い効果が得られる。 That is, it is confirmed that the recording sensitivity can be greatly improved by using an In alloy / SiO mixed recording film as in the present invention. Thus, even if the composition of the In alloy is different, the invention example has a laser power of about 8 mW as well as a laser power of about 5 mW, as compared with the comparative example of the recording film made only of the In alloy, as long as it is within the composition range of the present invention. Even with a lower laser power, the effect of high signal modulation and signal C / N ratio can be obtained.
[0111] 発明例 5 : [0111] Invention Example 5:
基板 1としては、発明例 1と同じ条件のポリカーボネート基板を用いた。その基板表 面に、 DCスパッタリング法によって、厚さ 12nm相当の In— 40at%Coの、 Coを含む In合金を成膜すると同時に、 RFスパッタリング法によって厚さ 1. 5nm相当の SiOを 成膜した（コスパッタリング)。そして、 In合金/ SiO誘電体の混合比率が体積比にて 8 : 1となる総膜厚 13. 5nmの記録膜 4を成膜した。この記録層 4形成のためのスパッ タリング条件は、到達真空度： 10— 5Torr以下、 Arガス圧： lmTorr、 DCスパッタ成膜 パワー及び RFスパッタ成膜パワーはそれぞれ 100W及び 90Wとして、成膜レート比 力 ¾C : RF = 8 : 1となる様に設定した。次いで、記録膜 4の上に、発明例 1と同じ条件 で光透過層 6を形成した。 As the substrate 1, a polycarbonate substrate having the same conditions as in Invention Example 1 was used. On the surface of the substrate, an In alloy containing Co—40 at% Co equivalent to 12 nm in thickness was formed by DC sputtering, and at the same time, SiO equivalent to 1.5 nm in thickness was formed by RF sputtering. (Cosputtering). Then, a recording film 4 having a total film thickness of 13.5 nm was formed so that the mixing ratio of In alloy / SiO dielectric was 8: 1 by volume. Sputtering Taringu conditions for the recording layer 4 formed, ultimate vacuum: 10- 5 Torr or less, Ar gas pressure: LmTorr, as each DC sputtering power and RF sputtering power 100W and 90W, the film forming rate Specific power ¾C was set to be RF = 8: 1. Next, a light transmission layer 6 was formed on the recording film 4 under the same conditions as in Invention Example 1.
[0112] 比較例 3 : [0112] Comparative Example 3:
発明例 1と同じ条件のポリカーボネート基板を用いた。その基板表面に、発明例 5と 同じく DCスパッタリング法によって、厚さ 12nm相当の In— 40at%Coの In合金のみ の記録膜 4を成膜した。この記録層 4形成のためのスパッタリング条件は、到達真空 度： 10— 5Torr以下、 Arガス圧： lmTorr、 DCスパッタ成膜パワーは 100Wとした。次 いで、記録膜 4の上に、発明例 1と同じ光透過層 6を形成した。 A polycarbonate substrate having the same conditions as in Invention Example 1 was used. On the surface of the substrate, a recording film 4 made of only an In-40 at% Co alloy equivalent to 12 nm in thickness was formed by DC sputtering as in Invention Example 5. The sputtering conditions for the recording layer 4 formed, ultimate vacuum: 10- 5 Torr or less, Ar gas pressure: lmTorr, DC sputtering power was set at 100W. Next, the same light transmission layer 6 as that of Invention Example 1 was formed on the recording film 4.
[0113] (実施例 4) [0113] (Example 4)
光ディスクの記録膜 4における In合金の組成の影響を調査した。本調査では、 In合
金組成の影響のみを調査するために、敢えて、本発明の In合金と酸化物との混合物 力、らなる記録膜とはせず、 In合金のみからなる記録膜にて試験を行った。その上で、 この記録膜の In合金の組成を種々変えて、記録特性と信号変調度につき評価した。 これらの結果を表 1、 2に示す。 The effect of the In alloy composition on the recording film 4 of the optical disk was investigated. In this study, In In order to investigate only the influence of the gold composition, the test was conducted with a recording film made of only the In alloy, not the recording force of the mixture of the In alloy and the oxide of the present invention. Then, the recording characteristics and the signal modulation degree were evaluated by changing the composition of the In alloy of the recording film. These results are shown in Tables 1 and 2.
[0114] 光ディスクの製作： [0114] Production of optical disc:
発明例 1と同じ（条件の）ポリカーボネート基板を用いた。その基板表面に、発明例 1と同じく、 DCマグネトロンスパッタリング法によって記録膜 4を形成した。スパッタリン グターゲットとしては、直径 6インチの Inターゲット上に添加元素のチップ（5mm角も しくは 1 Omm角 )を置!/、た複合ターゲットを用レ、た。 The same (condition) polycarbonate substrate as in Invention Example 1 was used. A recording film 4 was formed on the substrate surface by DC magnetron sputtering as in Invention Example 1. As the sputtering target, an additive element chip (5 mm square or 1 Omm square) was placed on an In target with a diameter of 6 inches and a composite target was used.
[0115] スパッタ条件は、到達真空度： 3 X 10— 6Torr以下、 Arガス圧： 2mTorr、 DCスパッ タ成膜パワー： 100Wとした。膜厚は、 BD— Rディスクの未記録状態の SUM2信号（ 反射率と相関ある出力信号)レベルが 280mV以上を確保出来る膜厚となるよう 12〜 21nmの範囲で調整した（なお、比較例の合金では、 280mV以上確保出来ないもの あり）。 [0115] The sputtering conditions, the ultimate vacuum: 3 X 10- 6 Torr or less, Ar gas pressure: 2 mTorr, DC spatter deposition power: was 100W. The film thickness was adjusted in the range of 12 to 21 nm so that the unrecorded SUM2 signal level of the BD-R disc (output signal correlating with reflectivity) was 280 mV or more. Some alloys cannot secure more than 280mV).
[0116] 次いでその上に、紫外線硬化性樹脂（日本化薬社製商品名「BRD— 130」）をスピ ンコートした後、紫外線硬化させて膜厚 100 ± 15 mの光透過層 3を形成した。 [0116] Next, a UV curable resin (trade name “BRD-130” manufactured by Nippon Kayaku Co., Ltd.) was spin-coated thereon, followed by UV curing to form a light transmission layer 3 having a thickness of 100 ± 15 m. .
[0117] 光ディスクの評価法については、光ディスク評価装置 (パルステック工業社製の商 品名「ODU—1000」、記録レーザー波長： 405nm、 NA (開口数）：0· 85)、スぺタト ラムアナライザー（アドバンテスト社製の商品名「R3131R」）を用いた。この際、線速 は 4· 9m/sで、未記録状態の SUM2レベル、記録レーザパワー 4mWから 12mW の範囲において長さ 0. 6 111の記録マーク（2508の8111 & Discの 8T信号に相当 )を繰り返して形成し、再生レーザパワー 0. 3mWにおける信号読み取り時の記録再 生時の最大 C/N値を評価した。 [0117] The optical disk evaluation method is as follows: Optical disk evaluation device (trade name “ODU-1000” manufactured by Pulstec Industrial Co., Ltd., recording laser wavelength: 405 nm, NA (numerical aperture): 0 · 85), spectrum analyzer (Trade name “R3131R” manufactured by Advantest) was used. At this time, the linear velocity is 4 · 9m / s, the unrecorded SUM2 level, and the recording laser power in the range of 4mW to 12mW, the length of 0.6 111 recording mark (corresponds to 811 signal of 2508 8111 & Disc) The maximum C / N value at the time of recording / reproducing at the time of signal reading with a reproducing laser power of 0.3 mW was evaluated.
[0118] またタイムインターバルアナライザー（横河電機社製商品名 TA520)を用い、記録 レーザノ ヮ一 4mW力、ら 12mWの範囲において最短長さ 0. 15 m力、ら 0. 075 111 単位で、最長長さ 0. 6 μ mまでの長さの記録マーク（25GBの Blu-ray Discの 2T〜8 T信号に相当）をランダムに繰り返し形成した際のジッター値の評価を行った。ジッタ 一値の評価は 3トラック連続で記録した後、中心のトラックの信号における値を「ジッタ
一値 (連続 3トラック記録時）」としている。また同時に「ジッター値 (連続 3トラック記録 時）」が最小値となる記録レーザパワーも評価した。 [0118] Also, using a time interval analyzer (trade name TA520, manufactured by Yokogawa Electric Corporation), the longest length in the range of 4 mW force, 12 mW, 0.15 m force, etc. We evaluated the jitter value when recording marks (corresponding to 2T-8T signals of 25GB Blu-ray Disc) with a length of up to 0.6 μm were randomly formed. Jitter To evaluate the single value, record three consecutive tracks, then change the value in the center track signal to `` jitter ''. “One value (during continuous 3-track recording)”. At the same time, the recording laser power at which the “jitter value (during continuous three-track recording)” is the minimum value was also evaluated.
[0119] 表 1は、光ディスクの記録膜 4の In合金が Ni、 Coの一種または二種を含む、実施例 [0119] Table 1 shows examples in which the In alloy of the recording film 4 of the optical disc contains one or two of Ni and Co.
(発明例）及び比較例のそれぞれの光記録媒体における未記録状態の SUM2のレ ベルと 8T信号記録再生時の C/N値を示した表である。ここで、表 1、 2の各実施例 は、表 1、 2における本発明組成範囲内の In合金のみからなる記録膜の実施例の意 味であり、前記した各実施例;!〜 3における In合金 +酸化物の混合物からなる記録 膜とは別である。また、表 1の比較例 1〜4も、表 1における本発明組成範囲外の In合 金のみからなる記録膜の比較例の意味であり、前記図 5〜； 11の比較例 1〜3とは別 である。 6 is a table showing the unrecorded SUM2 level and the C / N value at the time of 8T signal recording / reproduction in each of the optical recording media of (Invention) and Comparative Example. Here, each example in Tables 1 and 2 means an example of a recording film made of only an In alloy within the composition range of the present invention in Tables 1 and 2, and in each of the above-described Examples;! To 3 It is different from the recording film made of a mixture of In alloy + oxide. Further, Comparative Examples 1 to 4 in Table 1 also mean a comparative example of a recording film consisting only of In alloy outside the composition range of the present invention in Table 1, and the Comparative Examples 1 to 3 in FIGS. Is different.
[0120] 表 2は、光ディスクの記録膜 4の In合金力 S、 Ni、 Coに加えて、 Sn、 Bi、 Ge、 Siから 選ばれる一種または二種以上を含む、実施例 (発明例）それぞれの光記録媒体にお ける未記録状態の SUM2のレベル、 8T信号記録再生時の C/N値、ジッター値（連 続 3トラック記録時）が最小値となる記録パワー及びジッター値 (連続 3トラック記録時) を示した表である。 [0120] Table 2 shows examples (invention examples) each including one or more selected from Sn, Bi, Ge, and Si in addition to the In alloying force S, Ni, and Co of the recording film 4 of the optical disk. Recording power and jitter values (3 continuous tracks) with the minimum SUM2 level, C / N value during 8T signal recording and playback, and jitter value (during continuous 3 track recording) It is a table showing (at the time of recording).
[0121] 表 1、 2において、最大 C/N値が得られる記録レーザーパワーは、 6mWから 10m Wの範囲で、表中、未記録状態の SUM2のレベルが 280mV以上には〇を、これに 満たないものは Xを付した。また、 8T信号記録再生時の C/N値が 50dB以上には 〇を、これに満たないものは Xを付している。 [0121] In Tables 1 and 2, the recording laser power that gives the maximum C / N value is in the range of 6 mW to 10 mW. In the table, the unrecorded SUM2 level is over 280 mV. Those not satisfying are marked with X. In addition, when the C / N value at the time of 8T signal recording / playback is 50 dB or more, ○ is marked, and X is marked if it is less than this.
[0122] 表 1より、 Ni、 Coを含む In合金記録膜 4を備えた光ディスクは、各比較例（Pt、 Au あるいは Vを含む In合金）に比べて、 SUM2のレベル及び C/N値がいずれも高ぐ 優れた記録特性を発揮するものであることがわかる。したがって、本発明の In合金と 酸化物との混合物からなる記録膜の、 In合金における Ni、 Co含有乃至 Ni、 Co含有 量の意義が裏付けられる。 [0122] From Table 1, the optical disk with In alloy recording film 4 containing Ni and Co has a SUM2 level and C / N value that is higher than that of each comparative example (In alloy containing Pt, Au, or V). It can be seen that both have high recording properties. Therefore, the significance of Ni, Co content or Ni, Co content in the In alloy of the recording film comprising the mixture of In alloy and oxide of the present invention is supported.
[0123] また、表 2から、 Ni、 Coに加えて、更に Bi、 Sn、 Ge、 Siを含有する In合金記録膜 4 を備えた光ディスクは、同様に SUM2のレベル及び C/N値がいずれも高い上に、こ れら Bi、 Sn、 Ge、 Siを含まない表 1の実施例 1に相当する参考例に比べ、ジッター値 も低い値が得られており、さらに優れた記録特性を有していることが判明する。したが
つて、本発明の In合金と酸化物との混合物からなる記録膜の、 In合金における Ni、 C oに加えて、更に Bi、 Sn、 Ge、 Siを含有する乃至 Bi、 Sn、 Ge、 Si含有量の意義が裏 付けられる。 [0123] Further, from Table 2, in addition to Ni and Co, the optical disc provided with the In alloy recording film 4 containing Bi, Sn, Ge, and Si also has the same SUM2 level and C / N value. In addition, the jitter value is lower than that of the reference example corresponding to Example 1 in Table 1 that does not contain Bi, Sn, Ge, and Si, and has excellent recording characteristics. It turns out that But Therefore, the recording film comprising the mixture of In alloy and oxide of the present invention contains Bi, Sn, Ge, and Si in addition to Ni and Co in the In alloy or Bi, Sn, Ge, and Si. The significance of quantity is supported.
[0124] [表 1] [0124] [Table 1]
[0125] [表 2]
口： ^系 組成 (ICP) 膜厚 SUM2 8 T C/N 記録パワー ジッター 実施例 18 In- Go Co 55.6at% 13nm 0338mV O ≥50dB 7. ImW 8.4% 実施例 19 In-Co Co 65.1at% 18nm 0379mV O ≥50dB 8.M 11.6% 実施例 20 In- Co- Sn Co 46.1at% Sn 1.05at% 12nm 0291mV O ≥50dB 6.6m 7.8% 実施例 21 1 n-Co-Sn Co 47.1at% Sn 1.75at% 12nm 0289mV O ≥50dB 6.0mW 7.9% 実施例 22 In- Co- Bi Co 29at% Bi 19at% 15nm O310mV O ≥50dB 7.4mW 8.6% 実施例 23 In-Ni-Sn Ni 31at% Sn 15at¾ 15nm 0311mV O ≥50dB 7.8mW 8.8% 実施例 24 In-Ni-Sn Ni 35at Sn 15at% 15nm 0365mV O ≥50dB 7.6mW 10.1% 実施例 25 In-Ni-Sn Ni 37at% Sn 17at% 15nm 0335mV O ≥50dB 8.0mW 9.9% 実施例 26 In-Co-Bi Co 39at% Bi 10at% 12nm O280mV O ≥50dB 7.2mW 9.5% 実施例 27 1 n-Co-6e Co 50.4at% Ge 7.4at% 14nm O340mV O ≥50dB 6.½W 9.0% 実施例 28 In-Co-Si Co 42.8at% Si 6.4at% 15nm 0351mV O ≥50dB 7.2nW 8.7% 実施例 29 n-Co-Ni-Sn Co 37.4at% Ni 9.2at¾ 12nm 0344mV O ≥50dB 6.6mW 6.9% [0125] [Table 2] Mouth: ^ System composition (ICP) Film thickness SUM2 8 TC / N Recording power jitter Example 18 In- Go Co 55.6at% 13nm 0338mV O ≥50dB 7. ImW 8.4% Example 19 In-Co Co 65.1at% 18nm 0379mV O ≥50dB 8.M 11.6% Example 20 In- Co-Sn Co 46.1at% Sn 1.05at% 12nm 0291mV O ≥50dB 6.6m 7.8% Example 21 1 n-Co-Sn Co 47.1at% Sn 1.75at% 12nm 0289mV O ≥50dB 6.0mW 7.9% Example 22 In- Co- Bi Co 29at% Bi 19at% 15nm O310mV O ≥50dB 7.4mW 8.6% Example 23 In-Ni-Sn Ni 31at% Sn 15at¾ 15nm 0311mV O ≥50dB 7.8mW 8.8% Example 24 In-Ni-Sn Ni 35at Sn 15at% 15nm 0365mV O ≥50dB 7.6mW 10.1% Example 25 In-Ni-Sn Ni 37at% Sn 17at% 15nm 0335mV O ≥50dB 8.0mW 9.9% Implementation Example 26 In-Co-Bi Co 39at% Bi 10at% 12nm O280mV O ≥50dB 7.2mW 9.5% Example 27 1 n-Co-6e Co 50.4at% Ge 7.4at% 14nm O340mV O ≥50dB 6.½W 9.0% Implementation Example 28 In-Co-Si Co 42.8at% Si 6.4at% 15nm 0351mV O ≥50dB 7.2nW 8.7% Example 29 n-Co-Ni-Sn Co 37.4at% Ni 9.2at¾ 12nm 0344mV O ≥50dB 6.6mW 6.9%
Sn 4.7at% Sn 4.7at%
実施例 30 In - Co- Nト Sn Co 36.5at% Ni 10.7at% 12nm 0353mV O ≥50dB 6.½W 7.3% Example 30 In-Co-N to Sn Co 36.5at% Ni 10.7at% 12nm 0353mV O ≥50dB 6.½W 7.3%
Sn 9.8at% Sn 9.8at%
実施例 31 In-Co-Ni-Sn Co 41.4at% Ni 8.5at% 12nm O309mV O ≥50dB 6.械 6.9% Example 31 In-Co-Ni-Sn Co 41.4at% Ni 8.5at% 12nm O309mV O ≥50dB 6. Mechanical 6.9%
Sn 8.4at% Sn 8.4at%
実施例 32 In-Co-Ni-Sn Co 34.0at% Ni 16.6at% 12nrn O308mV O ≥50dB 6.2mW 6.9% Example 32 In-Co-Ni-Sn Co 34.0at% Ni 16.6at% 12nrn O308mV O ≥50dB 6.2mW 6.9%
Sn 5.7at% Sn 5.7at%
実施例 33 In- Co- Nト Sn Co 34.1at% Ni 13.2at 13nm 0346mV O ≥50dB 6.6mW 7.4% Example 33 In-Co-N to Sn Co 34.1at% Ni 13.2at 13nm 0346mV O ≥50dB 6.6mW 7.4%
Sn 10.9at% Sn 10.9at%
実施例 34 In-Co-Ni-Sn Co 32.5at% Ni 10.7at% Hnm 035½V O ≥50dB 6.6mW 7.4% Example 34 In-Co-Ni-Sn Co 32.5at% Ni 10.7at% Hnm 035½V O ≥50dB 6.6mW 7.4%
Sn 5.2at% Sn 5.2at%
実施例 35 In-Co- i-Sn Co 34.2at Ni 14.7at% 1 nm 0312mV O ≥50dB 6.M 8.1% Example 35 In-Co-i-Sn Co 34.2at Ni 14.7at% 1 nm 0312mV O ≥50dB 6.M 8.1%
Sn 3.8at% Sn 3.8at%
実施例 36 In-Co-Ni-Sn Co 32.2at% Ni 12.5at 11nm 0286mV O ≥50dB 6.2mW 7.8% Example 36 In-Co-Ni-Sn Co 32.2at% Ni 12.5at 11nm 0286mV O ≥50dB 6.2mW 7.8%
Sn 7.1at% Sn 7.1at%
実施例 37 In-Oo-Ni-Sn Co 34.4at% Ni 17.5at% 13nm 0333mV O ≥50dB 6.6mW 7.8% Example 37 In-Oo-Ni-Sn Co 34.4at% Ni 17.5at% 13nm 0333mV O ≥50dB 6.6mW 7.8%
Sn 5.3at% Sn 5.3at%
(実施例 1 ) In-Co Co 22at% 12nm 0317mV O ≥50dB 6.8mW 11.6% (Example 1) In-Co Co 22at% 12nm 0317mV O ≥50dB 6.8mW 11.6%
本発明を特定の態様を参照して詳細に説明した力 s、本発明の精神と範囲を離れる ことなく様々な変更および修正が可能であることは、当業者にとって明らかである。 なお、本出願は、 2006年 12月 20日付けで出願された日本特許出願（特願 2006 343039)、 2007年 5月 8日付けで出願された日本特許出願（特願 2007— 1236 57)、及ぴ 2007年 12月 7日付けで出願された日本特許出願（特願 2007— 31733 8)に基づいており、その全体が引用により援用される。
また、ここに引用されるすべての参照は全体として取り込まれる。 It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention as described in detail with reference to specific embodiments. This application is based on a Japanese patent application filed on December 20, 2006 (Japanese Patent Application 2006 343039), a Japanese patent application filed on May 8, 2007 (Japanese Patent Application 2007-123657), It is based on a Japanese patent application filed on December 7, 2007 (Japanese Patent Application No. 2007-31733 8), which is incorporated by reference in its entirety. Also, all references cited herein are incorporated as a whole.
産業上の利用可能性 Industrial applicability
本発明によれば、比較的低いレーザパワーによって穴開け (記録）が可能となり、良 好な記録特性を持ちつつ、さらに良好な信号変調度が得られる記録膜を有する光情 報記録媒体を提供することができる。この結果、本発明の光情報記録媒体は、現行 の CD (Compact Disc)や DVD (DigitalVersatile Disc)、次世代の光情報記録媒体（ HD DVDや Blu-ray Disc)として用いられ、特には、青紫色のレーザを用いる追記 型の高密度光情報記録媒体として好適に用いられる。
According to the present invention, there is provided an optical information recording medium having a recording film that enables punching (recording) with a relatively low laser power, has a good recording characteristic, and obtains a better signal modulation degree. can do. As a result, the optical information recording medium of the present invention is used as a current CD (Compact Disc), DVD (Digital Versatile Disc), or next-generation optical information recording medium (HD DVD or Blu-ray Disc). It is suitably used as a write-once high-density optical information recording medium using a violet laser.
Claims
[1] エネルギービームの照射により記録マークが形成される記録膜を有する光情報記 録媒体であって、この記録膜が In合金と酸化物との混合物からなる光情報記録媒体 [1] An optical information recording medium having a recording film on which a recording mark is formed by irradiation with an energy beam, wherein the recording film is made of a mixture of an In alloy and an oxide
〇 Yes
[2] 前記光情報記録媒体の記録膜における In合金力 Niおよび Coの一種または二種 を；!〜 65原子％含み、残部 Inおよび不可避的不純物からなる請求項 1に記載の光 情報記録媒体。 [2] The optical information recording medium according to claim 1, comprising one or two of In alloying force Ni and Co in the recording film of the optical information recording medium; and comprising the remainder In and inevitable impurities; .
[3] 前記光情報記録媒体の記録膜における In合金における前記 Niおよび Coの一種ま たは二種の含有量が 50原子％以下である請求項 2に記載の光情報記録媒体。 3. The optical information recording medium according to claim 2, wherein the content of one or two of Ni and Co in the In alloy in the recording film of the optical information recording medium is 50 atomic% or less.
[4] 前記光情報記録媒体の記録膜における In合金における前記 Niおよび Coの一種ま たは二種の含有量が 20原子％以上である請求項 2に記載の光情報記録媒体。 4. The optical information recording medium according to claim 2, wherein the content of one or two of Ni and Co in the In alloy in the recording film of the optical information recording medium is 20 atomic% or more.
[5] 前記光情報記録媒体の記録膜における In合金力 Niおよび Coの一種または二種 を；!〜 65原子％含み、更に、 Sn、 Bi、 Geおよび Siから選ばれる一種または二種以上 を 19原子％以下（0原子％を含まない)含有し、残部 Inおよび不可避的不純物から なる請求項 1に記載の光情報記録媒体。 [5] One or two types of In alloying forces Ni and Co in the recording film of the optical information recording medium;! To 65 atomic%, and further, one or more types selected from Sn, Bi, Ge and Si 2. The optical information recording medium according to claim 1, comprising 19 atomic% or less (not including 0 atomic%), the balance being In and inevitable impurities.
[6] 前記光情報記録媒体の記録膜における酸化物が、シリコン、アルミニウムおよび二 ォブの各酸化物から選択される一種か、またはこれら二種以上の複合酸化物である 請求項 1乃至 5の!/、ずれか 1項に記載の光情報記録媒体。 6. The oxide in the recording film of the optical information recording medium is one kind selected from silicon, aluminum, and two oxides, or a composite oxide of two or more of these. The optical information recording medium according to item 1.
[7] 前記光情報記録媒体の記録膜における In合金と酸化物との混合比率が、 In合金と 酸化物との体積比である（In合金体積) / (酸化物体積）で 3〜； 10の範囲である請求 項 1乃至 6のいずれ力、 1項に記載の光情報記録媒体。
[7] The mixing ratio of the In alloy and the oxide in the recording film of the optical information recording medium is a volume ratio of the In alloy and the oxide (In alloy volume) / (oxide volume) of 3 to 10; The optical information recording medium according to any one of claims 1 to 6, wherein the optical information recording medium is in a range of:
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006343039 | 2006-12-20 | ||
| JP2006-343039 | 2006-12-20 | ||
| JP2007-123657 | 2007-05-08 | ||
| JP2007123657 | 2007-05-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2008075683A1 true WO2008075683A1 (en) | 2008-06-26 |
Family
ID=39536312
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/JP2007/074319 WO2008075683A1 (en) | 2006-12-20 | 2007-12-18 | Optical information recording medium |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP2008302688A (en) |
| TW (1) | TW200841337A (en) |
| WO (1) | WO2008075683A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4969625B2 (en) | 2008-11-12 | 2012-07-04 | 株式会社神戸製鋼所 | Optical information recording medium |
| WO2010055865A1 (en) * | 2008-11-12 | 2010-05-20 | 株式会社神戸製鋼所 | Recording layer for optical information recording medium, optical information recording medium, and sputtering target |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61195943A (en) * | 1985-02-25 | 1986-08-30 | Hitachi Ltd | Alloy having variable spectral reflectance and recording material |
| JPS648521A (en) * | 1987-06-30 | 1989-01-12 | Sony Corp | Optical recording medium |
| JP2004178673A (en) * | 2002-11-26 | 2004-06-24 | Toshiba Corp | Phase change optical recording medium |
| JP2005022409A (en) * | 2003-06-13 | 2005-01-27 | Matsushita Electric Ind Co Ltd | Optical information recording medium and method for manufacturing the same |
| JP2005190647A (en) * | 2003-12-03 | 2005-07-14 | Ricoh Co Ltd | Phase-change optical recording medium |
-
2007
- 2007-12-07 JP JP2007317338A patent/JP2008302688A/en active Pending
- 2007-12-18 WO PCT/JP2007/074319 patent/WO2008075683A1/en active Application Filing
- 2007-12-20 TW TW096148959A patent/TW200841337A/en unknown
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61195943A (en) * | 1985-02-25 | 1986-08-30 | Hitachi Ltd | Alloy having variable spectral reflectance and recording material |
| JPS648521A (en) * | 1987-06-30 | 1989-01-12 | Sony Corp | Optical recording medium |
| JP2004178673A (en) * | 2002-11-26 | 2004-06-24 | Toshiba Corp | Phase change optical recording medium |
| JP2005022409A (en) * | 2003-06-13 | 2005-01-27 | Matsushita Electric Ind Co Ltd | Optical information recording medium and method for manufacturing the same |
| JP2005190647A (en) * | 2003-12-03 | 2005-07-14 | Ricoh Co Ltd | Phase-change optical recording medium |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2008302688A (en) | 2008-12-18 |
| TW200841337A (en) | 2008-10-16 |
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