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  • 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
  • G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
  • G11B7/254—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of protective topcoat layers
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  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
  • C04B35/46—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates
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  • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
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  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
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  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering
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  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering
  • C23C14/3407—Cathode assembly for sputtering apparatus, e.g. Target
  • C23C14/3414—Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• • 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
  • G11B7/26—Apparatus or processes specially adapted for the manufacture of record carriers
  • G11B7/266—Sputtering or spin-coating layers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes
  • H01J37/34—Gas-filled discharge tubes operating with cathodic sputtering
  • H01J37/3411—Constructional aspects of the reactor
  • H01J37/3414—Targets
  • H01J37/3426—Material
  • H01J37/3429—Plural materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
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  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
  • C04B2235/40—Metallic constituents or additives not added as binding phase
  • C04B2235/408—Noble metals
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  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
  • C04B2235/54—Particle size related information
  • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
  • C04B2235/5436—Particle size related information expressed by the size of the particles or aggregates thereof micrometer sized, i.e. from 1 to 100 micron
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  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
  • C04B2235/74—Physical characteristics
  • C04B2235/77—Density
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  • C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
  • C04B2235/9646—Optical properties
• • 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
  • G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
  • G11B7/254—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of protective topcoat layers
  • G11B2007/25408—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of protective topcoat layers consisting essentially of inorganic materials
• • 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
  • G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
  • G11B7/257—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers
  • G11B7/2578—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers consisting essentially of inorganic materials

Definitions

• the present invention relates to a thin film mainly comprising titanium oxide having a high refractive index and a low extinction coefficient, a sintered sputtering target mainly comprising titanium oxide suitable for producing the thin film, and a method of producing a thin film mainly comprising titanium oxide.
• CD-RW appeared for the first time in 1977 as a rewritable CD, and is the most popular phase-change optical disk today. This CD-RW has a rewrite cycle of approximately 1000 times.
• DVD-RW for use as a DVD has been developed and commercialized, and the layer structure of this disk is identical with or similar to the structure of CD-RW.
• This DVD-RW has a rewrite cycle of approximately 1000 to 10000 times.
• These disks record, replay and rewrite information by irradiating an optical beam to cause an optical change of the recording material such as its transmittance or reflectance, and are electronic parts that have spread rapidly.
• a phase-change optical disc used as a CD-RW or a DVD-RW has a four-layer structure wherein both sides of a recording thin film layer of Ag—In—Sb—Te system or Ge—Sb—Te system or the like are sandwiched between the protective layers of high-melting dielectrics such as ZnS.SiO 2 or the like, and a silver or silver alloy or aluminum alloy reflective film is additionally provided thereto. Further, in order to increase the rewrite cycle, an interface layer is provided between a memory layer and a protective layer as necessary.
• the reflective layer and the protective layer are demanded to have an optical function capable of increasing the reflectance difference between the amorphous portion and the crystal portion of the recording layer, and also demanded to have a function of protecting the recording thin film from moisture and heat deformation as well as a function for controlling the thermal conditions upon recording (refer to Non-Patent Document 1).
• Patent Document 1 has a first information layer formed on a substrate 1 and a second information layer formed on a substrate 2 from the incident direction of the laser beam, and these information films are laminated so as to face each other via an interlayer.
• the first information layer is configured from a recording layer and a first metal reflective layer
• the second information layer is configured from a first protective layer, a second protective layer, a recording layer and a second metal reflective layer.
• a hard coating layer for protecting the disk from scratches and contamination or the like, a thermal diffusion layer, and other layers may also be arbitrarily formed.
• various types of materials have been proposed for the foregoing protective layer, recording layer, reflective layer, and other layers.
• the protective layer of high-melting dielectrics must be durable against repeated thermal stress caused by the heating and cooling and must not allow such thermal effect to influence the reflective film or other areas, and it is also required to be thin and have low reflectivity and strength to prevent alteration. From this perspective, the dielectric protective layer plays an important role. In addition, needless to say, the recording layer, the reflective layer, the interference film layer and the like are also important from the perspective of enabling the electronic parts such as CDs and DVDs to fulfill their functions respectively.
• the respective thin films of a multilayer structure are usually formed with the sputtering method.
• This sputtering method is to make a positive electrode substrate and a negative electrode target face each other, and generates an electric field by applying a high voltage between the substrate and the target under an inert gas atmosphere.
• the sputtering method employs a principle where plasma is formed by the collision of ionized electrons and the inert gas at the stage of generating an electric field, the positive ions in this plasma collide with the target (negative electrode) surface to knock out the constituent atoms of the target, and the extruded atoms adhere to the opposing substrate surface to form a film.
• Patent Document 2 describes that the specific resistance value is set at 0.35 ⁇ cm or less in order to stabilize the discharge during the sputtering, and DC sputtering becomes possible, whereby a film of high refractive index can be obtained.
• Non-Patent Document 1 “ Kogaku ” magazine, volume 26, no. 1, pages 9 to 15
• Patent Document 1 Publication of Unexamined Japanese Application No. 2006-79710
• Patent Document 2 Japanese Patent No. 3836163
• Another object of this invention is to obtain a thin film that has superior transmittance, minimally deteriorates in reflectance, and is useful as an interference film or a protective film for an optical information recording medium. It is also possible to apply this thin film to a glass substrate; that is, which can be used as a heat reflective film, an antireflective film, and an interference filter.
• the present invention provides the following.
• a thin film mainly comprising titanium oxide wherein the thin film comprises components of Ti, Ag and O and contains 29.6 at % or more and 34.0 at % or less of Ti, 0.003 at % or more and 7.4 at % or less of Ag, and oxygen as the remainder thereof, and O/(2Ti+0.5Ag) as a ratio of oxygen to metals is 0.97 or more.
• a method of producing a thin film mainly comprising titanium oxide wherein a sintered sputtering target, which comprises components of Ti, Ag and O, contains the respective components at a composition ratio of (TiO 2-m ) 1-n Ag n (provided 0 ⁇ m ⁇ 0.5, and 0.0001 ⁇ n ⁇ 0.2), and has a specific resistance of 10 ⁇ cm or less, is used to perform sputtering under an argon gas atmosphere without oxygen or with 0.1 to 16% of oxygen, whereby formed on a substrate is a thin film which contains 29.6 at % or more and 34.0 at % or less of Ti, 0.003 at % or more and 7.4 at % or less of Ag, and oxygen as the remainder thereof, and in which O/(2Ti+0.5Ag) as a ratio of oxygen to metals is 0.97 or more.
• the present invention provides a thin film mainly comprising titanium oxide having a high refractive index and a low extinction coefficient, a sintered sputtering target mainly comprising titanium oxide suitable for producing the thin film, and a method of producing a thin film mainly comprising titanium oxide.
• the thin film obtained by the present invention yields a great effect as films and layers for an optical information recording medium.
• the thin film of the present invention has superior transmittance, minimally deteriorates in reflectance, and is particularly useful as an interference film or a protective film for an optical information recording medium.
• the protective layer of high-melting dielectrics must be durable against repeated thermal stress caused by the heating and cooling, and must not allow such thermal effect to influence the reflective film or other areas, and it is also required to be thin and have low reflectivity and strength to prevent alteration.
• the thin film mainly comprising titanium oxide of the present invention has properties that can be applied to such a material.
• the present invention since the oxygen content during sputtering can be adjusted to be within a low range, the present invention also yields an effect of being able to inhibit the deterioration of the deposition rate.
• the thin film mainly comprising titanium oxide of the present invention comprises, as described above, components of Ti, Ag and O, contains 29.6 at % or more and 34.0 at % or less of Ti, 0.003 at % or more and 7.4 at % or less of Ag, and oxygen as the remainder thereof, and has a composition ratio in which O/(2Ti+0.5Ag) as a ratio of oxygen to metals is 0.97 or more.
• the existence of Ag yields an effect of increasing the refractive index of the thin film. If the amount of Ag is less than 0.003, the effect of adding Ag is small, and if the amount of Ag exceeds 7.4, the extinction coefficient of the thin film in a wavelength region from 400 to 410 nm tends to increase. Thus, it is preferable that the abundance of Ag in the thin film is 0.03 at % or more and 7.4 at % or less.
• silver may partially exist as silver oxide (Ag 2 O, Ag 2 O 2 or the like), but such partial existence as silver oxide does not cause any particular problem, and the improvement in the refractive index is similarly acknowledged.
• the existence of silver oxide can be confirmed when the peak position of Ag3d is 368.0 eV or less in the XPS analysis.
• the material having a high refractive index obtained as described above will become a more favorable material since the possibility of optical multilayer film design can be expanded.
• the foregoing thin film is an amorphous film, and it is possible to obtain a film in which a refractive index in a wavelength region from 400 to 410 nm is 2.60 or more. It is further possible to obtain a thin film in which an extinction coefficient in a wavelength region from 400 to 410 nm is 0.1 or less, and even 0.03 or less.
• the foregoing wavelength region from 400 to 410 nm is the wavelength region of a blue laser.
• the refractive index is 2.60 or more in the foregoing wavelength region, and higher the refractive index, the more favorable it is.
• an extinction coefficient of 0.1 or less, and even 0.03 or less can be achieved, and lower the extinction coefficient, the more suitable it is for multilayering.
• This thin film mainly comprising titanium oxide is effective as an interference film or a protective film, and particularly useful as an optical recording medium.
• the foregoing thin film can be produced by using a sintered sputtering target having a composition ratio of (TiO 2-m ) 1-n Ag n (provided 0 ⁇ m ⁇ 0.5, and 0.0001 ⁇ n ⁇ 0.2), and a specific resistance of 10 ⁇ cm or less.
• deposition is preferably performed in an oxygen-containing atmosphere if the Ag content is particularly high.
• the oxygen in the sputtered film will increase.
• the sintered target of the present invention has a similar component composition as the thin film, but is not the same.
• the basic components of the target include Ti, Ag and O
• the composition ratio of the respective components is (TiO 2-m ) 1-n Ag n (provided 0 ⁇ m ⁇ 0.5, and 0.0001 ⁇ n ⁇ 0.2).
• the target has a specific resistance of 10 ⁇ cm or less.
• n is preferably set to 0.0001 or more and 0.2 or less.
• Conductivity of the target is required for increasing the sputtering efficiency, and the target of the present invention has such a condition and can be subject to DC sputtering.
• the deposition rate can be considerably adjusted based on the sputtering conditions; that is, based on whether the sputtering atmosphere is to be Ar+O 2 gas or only Ar gas. If the composition ratio is 0.05 ⁇ m ⁇ 0.5 or 0.01 ⁇ n ⁇ 0.2, since the extinction coefficient will increase when the sputtering atmosphere is only Ar gas, it is desirable to use Ar+O 2 gas. In the foregoing case, the target composition will be changed according to the purpose of production.
• the average grain size of the Ag phase existing in the sintered sputtering target is 15 ⁇ m or less, DC sputtering can be performed even more easily. Meanwhile, if the average grain size of the Ag phase exceeds 15 ⁇ m, abnormal discharge will occur frequently. Thus, the average grain size of the Ag phase is preferably 15 ⁇ m or less.
• This sintered sputtering target is used to perform sputtering under an argon gas atmosphere without oxygen or with 0.1 to 16% of oxygen, whereby a titanium oxide thin film containing Ag and/or Ag oxide can be formed on a substrate.
• a sintered sputtering target which comprises Ti, Ag and O, contains the respective components at a composition ratio of (TiO 2-m ) 1-n Ag n (provided 0 ⁇ m ⁇ 0.5, and 0.0001 ⁇ n ⁇ 0.2), and has a specific resistance of 10 ⁇ cm or less, is used to perform sputtering under an argon gas atmosphere without oxygen or with 0.1 to 16% of oxygen.
• a thin film which comprises 29.6 at % or more and 34.0 at % or less of Ti, 0.003 at % or more and 7.4 at % or less of Ag, and oxygen as the remainder thereof, and in which O/(2Ti+0.5Ag) as a ratio of oxygen to metals is 0.97 or more.
• the preferred conditions in producing the thin film mainly comprising titanium oxide of the present invention are that, if deposition is performed by way of DC sputtering and an oxygen gas ratio in the sputtering atmosphere is represented in b (%), the oxygen gas ratio is adjusted to be in a range of 0 ⁇ b ⁇ 83.3n ⁇ 0.17 when the composition ratio n of Ag in the sputtering target is 0.0001 ⁇ n ⁇ 0.01, and the oxygen gas ratio is adjusted to be in a range of 17n ⁇ 0.17 ⁇ b ⁇ 83.3n ⁇ 0.17 when the composition ratio n of Ag is 0.01
• high-purity titanium oxide (TiO 2 ) having an average grain size of 10 ⁇ m or less and high-purity (normally, 3N or higher) silver powder having an average grain size of 20 ⁇ m or less are used as the raw materials. These are blended to achieve the composition ratio of the present invention.
• the mixed powder is filled in a carbon die and subject to hot press.
• the hot press conditions may be changed according to the amount of the sintering material, but hot press is usually performed within the range of 800 to 1000° C. and bearing surface pressure of 100 to 500 kgf/cm 2 . Nevertheless, these conditions are merely representative conditions and can be selected arbitrarily, and there is no particular limitation of such conditions.
• the sintered compact is machined into a target shape.
• the basic components thereof are Ti, Ag and O, the respective components are contained at a composition ratio of (TiO 2-m ) 1-n Ag n (provided 0 ⁇ m ⁇ 0.5, and 0.0001 ⁇ n ⁇ 0.2), and silver (Ag) and/or silver oxide (Ag 2 O, Ag 2 O 2 or the like) is dispersed as fine particles in the matrix of titanium oxide.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar gas-0.5% O 2 gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w. It was possible to perform DC sputtering without any problem, and it was confirmed that the target has conductivity.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the film composition analyzed with EPMA was Ti: 32.9 at %, Ag: 0.7 at %, O: 66.4 at %, O/Ti: 2.02, and O/(2Ti+0.5Ag): 1.00.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar gas-2% O 2 gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w. It was possible to perform DC sputtering without any problem, and it was confirmed that the target has conductivity.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the film composition was Ti: 31.2 at %, Ag: 3.5 at %, O: 65.3 at %, O/Ti: 2.09, and O/(2Ti+0.5Ag): 1.02.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2.
• Example 2 the target obtained in Example 2 was subject to sputtering in an oxygen-free Ar atmosphere. Although it was possible to perform DC sputtering itself, problems arose in the properties of the thin film. Specifically, the refractive index of the obtained film decreased to 2.65, and the extinction coefficient increased to 0.23.
• the film composition was Ti: 32.3 at %, Ag: 3.7 at %, O: 64 at %, O/Ti: 1.98, and O/(2Ti+0.5Ag): 0.96.
• the sintered sputtering target of the present invention particularly when the Ag content is 1.5% or more, it is preferable to perform sputtering in an argon gas atmosphere containing 0.1 to 16% of oxygen.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar gas-2% O 2 gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w. Nevertheless, since abnormal discharge occurred during the DC sputtering and caused an unstable state, DC sputtering was discontinued and deposition was performed once again by way of RF sputtering.
• the film composition was Ti: 33.2 at %, Ag: 0 at %, O: 66.8 at %, O/Ti: 2.01, and O/(2Ti+0.5Ag): 1.01.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2.
• the refractive index decreased to 2.59, and the extinction coefficient was 0.004. Although there is no particular problem with the extinction coefficient, the refractive index decreased, abnormal discharge occasionally occurred, and there was a problem in that the stability of DC sputtering would deteriorate considerably.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w. It was possible to perform DC sputtering without any problem, and it was confirmed that the target has conductivity. The deposition rate improved considerably to 1.7 ⁇ /sec/kW.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the film composition was Ti: 33.3 at %, Ag: 0.04 at %, O: 66.66 at %, O/Ti: 2.00, and O/(2Ti+0.5Ag): 1.00.
• the Ag composition was analyzed with SIMS.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2.
• titanium oxide (TiO 2 ) having an average grain size of 10 ⁇ m and a purity of 4N (99.99%) and silver powder having an average grain size of 15 ⁇ m and a purity of 3N (99.9%) were used.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar gas-1% O 2 gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w. It was possible to perform DC sputtering without any problem, and it was confirmed that the target has conductivity.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the film composition was Ti: 32.2 at %, Ag: 1.4 at %, O: 66.4 at %, O/Ti: 2.06, and O/(2Ti+0.5Ag): 1.02.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar gas-10% O 2 gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w.
• the film composition was Ti: 26.3 at %, Ag: 17.5 at %, O: 56.2 at %, O/Ti: 2.14, and O/(2Ti+0.5Ag): 0.92.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar gas-2% O 2 gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w. It was possible to perform DC sputtering without any problem, and it was confirmed that the target has conductivity.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the film composition was Ti: 31.0 at %, Ag: 3.6 at %, O: 65.4 at %, O/Ti: 2.11, 0/(2Ti+0.5Ag): 1.03.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar gas-2% O 2 gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w. It was possible to perform DC sputtering without any problem, and it was confirmed that the target has conductivity.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the film composition was Ti: 31.4 at %, Ag: 3.5 at %, O: 65.1 at %, O/Ti: 2.07, and O/(2Ti+0.5Ag): 1.01.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2.
• the obtained target had a density of 97% and a specific resistance of 15 ⁇ cm.
• the grain size of the Ag phase in the target was 50 ⁇ m.
• the obtained target had a density of 96% and a specific resistance of 2 ⁇ cm.
• the grain size of the Ag phase in the target was 10 ⁇ m.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar gas-20% O 2 gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w.
• the deposition rate was extremely slow at 0.3 ⁇ /sec/kW, and it was at a level where practical application would be difficult.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the film composition was Ti: 30.7 at %, Ag: 3.1 at %, O: 66.2 at %, O/Ti: 2.16, and O/(2Ti+0.5Ag): 1.05.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2. Consequently, the refractive index decreased to 2.59 and the extinction coefficient was 0.005.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w. It was possible to perform DC sputtering without any problem, and it was confirmed that the target has conductivity. The deposition rate improved considerably at 1.8 ⁇ /sec/kW. Accordingly, it is evident that the deposition rate can be improved considerably by performing DC sputtering to the target in the Ar gas atmosphere.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the film composition was Ti: 33.1 at %, Ag: 0.7 at %, O: 66.2 at %, O/Ti: 2.00, and O/(2Ti+0.5Ag): 0.99.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2. Consequently, the refractive index increased to 2.67, and the extinction coefficient was 0.02. Thus, it was possible to form a favorable interference film or protective film for an optical recording medium.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w. It was possible to perform DC sputtering without any problem, and it was confirmed that the target has conductivity. As with Example 7, the deposition rate improved considerably at 1.8 ⁇ /sec/kW. Accordingly, it is evident that the deposition rate can be improved considerably by performing DC sputtering to the target in the Ar gas atmosphere.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the film composition was Ti: 33.3 at %, Ag: 0.2 at %, O: 66.5 at %, O/Ti: 2.00, and O/(2Ti+0.5Ag): 1.00.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2. Consequently, the refractive index increased to 2.66, and the extinction coefficient was 0.01. Thus, it was possible to form a favorable interference film or protective film for an optical recording medium.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w. It was possible to perform DC sputtering without any problem, and it was confirmed that the target has conductivity. The deposition rate improved at 1.6 ⁇ /sec/kW. Accordingly, it is evident that the deposition rate can be improved considerably by performing DC sputtering to the target in the Ar gas atmosphere.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the film composition was Ti: 33.3 at %, Ag: 0.02 at %, O: 66.68 at %, O/Ti: 2:00, and O/(2Ti+0.5Ag): 1.00.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2. Consequently, the refractive index increased to 2.62 and the extinction coefficient was 0.007. Thus, it was possible to form a favorable interference film or protective film for an optical recording medium.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w. It was possible to perform DC sputtering without any problem, and it was confirmed that the target has conductivity. The deposition rate improved at 1.6 ⁇ /sec/kW. Accordingly, it is evident that the deposition rate can be improved considerably by performing DC sputtering to the target in the Ar gas atmosphere.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the film composition was Ti: 33.3 at %, Ag: 0.005 at %, O: 66.695 at %, O/Ti: 2.00, and O/(2Ti+0.5Ag): 1.00.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2. Consequently, the refractive index increased to 2.61 and the extinction coefficient was 0.005. Thus, it was possible to form a favorable interference film or protective film for an optical recording medium.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar-4% O 2 gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w. It was possible to perform DC sputtering without any problem, and it was confirmed that the target has conductivity.
• the deposition rate was 0.7 ⁇ /sec/kW.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the film composition was Ti: 33.4 at %, Ag: 0.02 at %, O: 66.58 at %, O/Ti: 1.99, and O/(2Ti+0.5Ag): 1.00.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2. Consequently, the refractive index increased to 2.61 and the extinction coefficient was 0.007. Thus, it was possible to form a favorable interference film or protective film for an optical recording medium.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar+4% O 2 gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w. It was possible to perform DC sputtering without any problem, and it was confirmed that the target has conductivity.
• the deposition rate was 0.6 ⁇ /sec/kW.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the film composition was Ti: 33.4 at %, Ag: 0.006 at %, O: 66.594 at %, O/Ti: 1.99, and O/(2Ti+0.5Ag): 1.00.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2. Consequently, the refractive index increased to 2.60 and the extinction coefficient was 0.01. Thus, it was possible to form a favorable interference film or protective film for an optical recording medium.
• the sputtering target produced as described above was used to form a sputtered film on a glass substrate.
• DC sputtering was performed in an Ar gas atmosphere with a gas pressure of 0.5 Pa, a gas flow rate of 50 sccm, and a sputtering power of 500 to 1000 w. It was possible to perform DC sputtering without any problem, and it was confirmed that the target has conductivity. The deposition rate improved to 1.6 ⁇ /sec/kW. Accordingly, it is evident that the deposition rate can be improved considerably by performing DC sputtering to the target in the Ar gas atmosphere.
• a sputtered film of 500 ⁇ was formed on the glass substrate.
• the film composition was Ti: 33.8 at %, Ag: 0.04 at %, O: 66.16 at %, O/Ti: 1.96, and O/(2Ti+0.5Ag): 0.98.
• the refractive index and extinction coefficient of the sputtered film were measured.
• the refractive index and extinction coefficient were measured with an ellipsometer using a light wavelength of 405 nm. These results are also shown in Table 2. Consequently, the refractive index increased to 2.63 and the extinction coefficient was 0.09. Thus, it was possible to form a favorable interference film or protective film for an optical recording medium.
• Example 11 the target obtained in Example 11 was subject to sputtering in an oxygen-free Ar atmosphere. Although it was possible to perform DC sputtering itself, problems arose in the properties of the thin film. Specifically, the refractive index of the obtained film decreased to 2.58, and the extinction coefficient increased to 0.21.
• the film composition was Ti: 34.3 at %, Ag: 0.02 at %, O: 65.68 at %, O/Ti: 1.91, and O/(2Ti+0.5Ag): 0.96.
• the sintered sputtering target of the present invention particularly when the Ti content is 34.0% or more, it is preferable to perform sputtering in an argon gas atmosphere containing 0.1 to 16% of oxygen.
• Example 12 the target obtained in Example 12 was subject to sputtering in an oxygen-free Ar atmosphere. Although it was possible to perform DC sputtering itself, problems arose in the properties of the thin film. Specifically, the refractive index of the obtained film decreased to 2.54, and the extinction coefficient increased to 0.34.
• the film composition was Ti: 39.9 at %, Ag: 0.006 at %, O: 60.094 at %, O/Ti: 1.51, and O/(2Ti+0.5Ag): 0.75.
• the sintered sputtering target of the present invention particularly when the Ti content is 34.0% or more, it is preferable to perform sputtering in an argon gas atmosphere containing 0.1 to 16% of oxygen.
• the sputtering target contained the respective components at a composition ratio of (TiO 2-m ) 1-n Ag n (provided 0 ⁇ m ⁇ 0.5, and 0.0001 ⁇ n ⁇ 0.2), and contained Ag particles having an average grain size of 15 ⁇ m or less; the specific resistance was 10 ⁇ cm or less, and favorable results were achieved in which no abnormal discharge was observed.
• the present invention provides a thin film mainly comprising titanium oxide having a high refractive index and a low extinction coefficient, a sintered sputtering target mainly comprising titanium oxide suitable for producing the thin film, and a method of producing a thin film mainly comprising titanium oxide.
• the thin film obtained by the present invention can be used as films and layers for an optical information recording medium of electronic parts such as CDs and DVDs.
• the thin film of the present invention is particularly useful as an interference film or a protective film for an optical information recording medium having superior transmittance and with minimal deterioration in reflectance. Since a protective layer of high-melting dielectrics must be durable against repeated thermal stress caused by the heating and cooling, and must not allow such thermal effect to influence the reflective film or other areas, and since it is also required to be thin and have low reflectivity and strength to prevent alteration; the present invention is useful as such dielectric protective layer.
• a material having the foregoing properties can also be applied to architectural glass, automotive glass, CRTs and flat-panel displays; that is, such material can also be used as a heat reflective film, an antireflective film, and an interference filter.

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• 2008
  • 2008-12-09 WO PCT/JP2008/072295 patent/WO2009078306A1/ja active Application Filing
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