JP4320003B2 - Transflective reflective film and reflective film for optical information recording medium, optical information recording medium, and sputtering target - Google Patents

Description

  In the field of optical information recording media such as CD (Compact Disc), DVD (Digital Versatile Disc), Blu-ray Disc, HD DVD, etc., the present invention has high aggregation resistance, high light resistance, high heat resistance, Moreover, the semi-transmissive reflective film and reflective film for optical information recording media having high reflectivity, high transmittance, low absorption rate, and high thermal conductivity, and optical information used for film formation of these semi-transmissive reflective film or reflective film The present invention relates to a sputtering target for a recording medium, and an optical information recording medium provided with a transflective film or a reflective film thereof.

  There are several types of optical information recording media (optical disks), and they are roughly classified into three types: recording / reproducing systems, reproduction-only type, write-once type, and rewritable type. Also, there is a single-sided multilayer optical disc developed from the viewpoint of increasing the recording capacity, compared to a general single-sided optical disc. For example, in the case of a single-sided dual-layer optical disc, in order to perform signal recording or reproduction on the recording layer far from the incidence of laser light, the laser light is transmitted through the recording layer near the incidence, and the recording layer on the far side It is necessary to reflect and transmit the recording layer on the near side again. Therefore, a transflective film that can reflect and transmit the laser light is used for the recording layer on the side close to the incidence of the laser light.

  Examples of the material that functions as a semi-transmissive reflective film include metals such as Ag, Al, Au, Pt, Rh, and Cr, and single element semiconductors such as Si and Ge. Among these materials, (1) light efficiency (= reflectance + transmittance) is high, and (2) high against the blue-violet laser (wavelength: 405 nm) used in Blu-ray Disc and HD DVD. Attention has been focused on pure Ag or Ag alloy containing Ag as a main component, which shows reflectivity and (3) high thermal conductivity for appropriately diffusing heat generated from a recording film during signal recording. This Ag-based material has excellent performance as a transflective film for optical disks, that is, high reflectivity, high transmittance, low absorptivity (absorbance = 100% − (reflectance + transmittance)), and high thermal conductivity. In order to function as a semi-transmissive reflective film for optical discs that have long-term reliability, the Ag-based materials are subject to [1] aggregation resistance, [2] light resistance, and [3] heat resistance. There is a need to improve.

  [Problem 1] Aggregation resistance: Ag-based materials are likely to agglomerate under the influence of heat and halogen (fluorine, chlorine, bromine, iodine, etc.), in a high-temperature and high-humidity environment where optical disk reliability testing is performed, or When held in a state of being laminated with a halogen-containing organic material (organic dye recording film, protective layer, adhesive layer), the surface roughness of the thin film increases or becomes discontinuous due to aggregation, resulting in a transflective film There is a problem that the function as a reflective film deteriorates.

  [Problem 2] Light resistance: For example, a single-sided dual-layer read-only optical disc basically has a cross-sectional structure of polycarbonate (PC) substrate \ transflective film \ adhesive layer \ total reflection film \ PC substrate. When this optical disk is irradiated with an Xe lamp (lamp having a spectrum similar to sunlight) called a light resistance test, the reflectance decreases only when the transflective film is made of an Ag-based material, and a reproduction signal is generated. There is a problem that it becomes impossible to reproduce the signal when the value falls below the lower limit of the reflectivity at which the signal can be detected.

  [Problem 3] Heat resistance: For example, a single-sided dual-layer write-once optical disk basically consists of a PC substrate \ recording film \ transflective film \ spacer \ recording film \ total reflection film \ PC substrate cross-section, A rewritable optical disc with two layers on one side is basically a PC substrate \ dielectric protective film \ interface layer \ recording film \ interface layer \ dielectric protective film \ transflective film \ intermediate layer \ dielectric protective film \ interface layer \ It consists of a cross-sectional structure of recording film \ interface layer \ dielectric protective film \ total reflection film \ PC board. In these recordable optical discs including write once and rewritable, the recording film is heated to 300-600 ° C. during signal recording, so the heat load applied to the transflective film and the reflective film is very severe, and the influence of the heat load The crystal grain growth and discontinuous film formation that occur in the above-mentioned cases have a problem of deteriorating the function as a semi-transmissive reflective film or reflective film.

  So far, the following has been reported as an example of improvement (mainly alloying) of pure Ag. For example, in Patent Document 1, Au, Pd, Cu, Rh, Ru, Os, Ir, and Pt are added to Ag, or in Patent Document 2 and Patent Document 3, Au, Pd, Cu, Rh, Methods of improving corrosion resistance by adding Ru, Os, Ir, Be, and Pt, and further by adding Pd and Cu to Ag are proposed in Patent Documents 4 and 5, for example. In addition, in Patent Document 6, the inventors improve the structure stability (structure stability in the sense that Ag diffusion is suppressed and crystal grain growth is suppressed) by adding Nd to Ag. Presents.

However, Ag-based alloys having high agglomeration resistance, high light resistance and high heat resistance while having high reflectance, high transmittance, low absorption rate, and high thermal conductivity have not been found. There is a strong demand for an Ag-based alloy that has all the required characteristics.
US Patent No. 6007889 US Pat. No. 6,280,811 JP 2002-518596 A US Pat. No. 5,948,497 JP-A-6-208732 Japanese Patent No. 3365762

  The present invention has been made in view of the above circumstances, and its purpose is high aggregation resistance, high light resistance, high heat resistance, high reflectance, and high transmission that cannot be satisfied by pure Ag or conventional Ag alloys. , Low absorptivity, and high thermal conductivity, finding a translucent reflective film and a reflective film for optical information recording media, and their transflective properties, which can provide excellent recording / reproduction characteristics and long-term reliability. It is an object of the present invention to provide a sputtering target for an optical information recording medium used for forming a reflective film or a reflective film, and an optical information recording medium provided with a transflective film or a reflective film thereof.

The invention of claim 1 contains Li in an amount of 0.01 to 10 atomic% and includes La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. It is an Ag-based alloy containing a total of at least one selected from 0.1 to 2 atomic% and / or at least one selected from Au, Rh, and Pb in a total of 0.1 to 3 atomic%. An Ag-based alloy semi-transmissive reflective film or reflective film for an optical information recording medium is characterized.

  The invention of claim 2 is the Ag-based alloy transflective film or reflective film for optical information recording media according to claim 1, which contains 0.005 to 0.8 atomic% of Bi.

A third aspect of the present invention is an optical information recording medium comprising the Ag-based alloy transflective film according to the first or second aspect .

A fourth aspect of the present invention is an optical information recording medium comprising the Ag-based alloy reflective film according to the first or second aspect .

The invention of claim 5 contains Li in an amount of 0.01 to 10 atomic% and includes La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. It is an Ag-based alloy containing a total of at least one selected from 0.1 to 2 atomic% and / or at least one selected from Au, Rh, and Pb in a total of 0.1 to 3 atomic%. An Ag-based alloy sputtering target for an optical information recording medium is characterized.

The invention of claim 6 is the Ag-based alloy sputtering target for optical information recording media according to claim 5, which contains Bi in an amount of 0.005 to 0.8 atomic% .

  As described above, the transflective film and reflective film for an optical information recording medium of the present invention have high aggregation resistance, high light resistance, high heat resistance and high reflectance, high transmittance, low absorption, and high thermal conductivity. Therefore, the recording / reproducing characteristics and long-term reliability of the optical information recording medium can be remarkably improved. Further, the sputtering target of the present invention is suitably used for the above-described semi-transmissive reflective film or reflective film, and the semi-transmissive reflective film and reflective film formed using the above-described semi-transmissive reflective film or reflective film have an alloy composition and an alloy element distribution. Optical information recording with excellent in-plane film uniformity and low impurity component content, providing high performance as a semi-transmissive reflective film or reflective film, and excellent recording / reproduction characteristics and long-term reliability Media can be produced. The optical information recording medium of the present invention can greatly improve recording / reproduction characteristics and long-term reliability.

  Under the above-mentioned problems, the present inventors have provided an optical information recording medium having high aggregation resistance, high light resistance, high heat resistance, high reflectance, high transmittance, low absorption, and high thermal conductivity. In order to provide an Ag-based alloy semi-transmissive reflective film and a reflective film for use, extensive research has been conducted. In other words, various Ag-based alloy sputtering targets were used to form Ag-based alloy thin films having various alloy compositions by sputtering, and these film compositions, aggregation resistance, light resistance, heat resistance, reflectance, transmission The rate, absorption rate, and thermal conductivity were evaluated. As a result, the Ag-based alloy thin film containing Li in an amount of 0.01 to 10 atomic% is superior to the pure Ag thin film and the conventional Ag-based alloy thin film in that it has excellent aggregation resistance, light resistance, heat resistance and high reflectivity, high The present invention was completed by finding that it has transmittance, low absorption rate, and high thermal conductivity.

  The present inventors have clarified that the Ag-based alloy thin film containing Li is particularly excellent in light resistance as compared with a pure Ag thin film and a conventional Ag-based alloy thin film. For example, Xe lamp (lamp with a spectrum similar to sunlight) is irradiated onto a single-sided, dual-layer read-only optical disk with a basic cross-sectional structure of PC substrate / semi-transmissive reflective film / adhesive layer / total reflective film / PC substrate. When this is performed, the reflectance decreases only when the transflective film is an Ag-based material. This is a phenomenon that occurs when Ag is ionized by light irradiation and Ag ions diffuse to the adjacent PC substrate and / or adhesive layer. In the Ag-based alloy thin film containing Li according to the present invention, the sacrificial anticorrosion effect of Li, which has a higher ionization tendency than Ag, that is, preferential ionization of Li, suppresses ionization of Ag, and suppresses a decrease in reflectance due to light irradiation. Light resistance is improved. Furthermore, the Ag-based alloy thin film containing Li is not only excellent in light resistance but also improved in the aggregation resistance and heat resistance, which are the problems of Ag-based materials, and also has the high reflectivity that is a feature of Ag-based materials. It has been clarified that it is the best Ag-based alloy thin film having high transmittance, low absorption rate and high thermal conductivity.

  The Ag-based alloy transflective film and reflective film for optical information recording media of the present invention is characterized by containing Li in an amount of 0.01 to 10% (hereinafter referred to as atomic% unless otherwise specified). The content of Li increases with increasing content, but a clearer light resistance, agglomeration resistance, and heat resistance improvement effect can be obtained, but the reflectance, transmittance, and thermal conductivity decrease and the absorption increases. cause. Therefore, in the present invention, the content of Li is set to 0.01 to 10%. When the Li content is less than 0.01%, high light resistance, high aggregation resistance, and high heat resistance cannot be obtained, which is not preferable. On the other hand, when the Li content exceeds 10%, high reflectance is obtained. It is not preferable because high transmittance, low absorption rate, and high thermal conductivity cannot be obtained. Therefore, the preferable content of Li is 0.01 to 10%, the more preferable content is 0.05 to 8%, and the still more preferable content is 0.1 to 6%.

  It is also effective to add Bi to the Ag-based alloy transflective film for optical information recording medium and the reflective film of the present invention for the purpose of further improving the aggregation resistance, heat resistance and corrosion resistance. When the Bi content is less than 0.005%, no further effect of improving the aggregation resistance, heat resistance and corrosion resistance can be obtained, and when it exceeds 0.8%, the high reflectance, high transmittance and low absorption are obtained. Since high thermal conductivity cannot be obtained, the content is set to 0.005 to 0.8%, preferably 0.01 to 0.6%, more preferably 0.05 to 0.4%.

  In addition, in order to further improve the aggregation resistance and heat resistance of the Ag-based alloy transflective film and reflective film for optical information recording media of the present invention, rare earth metal elements Sc, Y, La, Ce, Pr, Nd , Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, it is also effective to contain 0.1 to 2% in total. Nd and / or Y is particularly effective as the rare earth metal element. When the total content of the rare earth metal elements is less than 0.1%, further improvement effects of the aggregation resistance and heat resistance cannot be obtained. When the total content exceeds 2%, high reflectance, high transmittance, low absorption rate, Since high thermal conductivity cannot be obtained, the total content is 0.1 to 2%, preferably 0.2 to 1%, more preferably 0.3 to 0.5%.

  Furthermore, at least one selected from Cu, Au, Rh, Pd, and Pt may be contained in the Ag-based alloy transflective film for optical information recording medium and the reflective film of the present invention for the purpose of further improving the corrosion resistance. It is valid. When the total content of at least one selected from Cu, Au, Rh, Pd, and Pt is less than 0.1%, a further improvement effect of corrosion resistance cannot be obtained. Since transmittance, low absorption rate, and high thermal conductivity cannot be obtained, the total content is set to 0.1 to 3%, preferably 0.2 to 2%, more preferably 0.3 to 1%.

  The Ag-based alloy transflective film for optical information recording media of the present invention is a thin film that functions to transmit and reflect in a recording layer other than the innermost recording layer in a single-sided multilayer optical disk with respect to the incident direction of laser light. The transmittance is about 45 to 80%, and the reflectance is about 5 to 30%. Further, the film thickness may be determined as appropriate within a range satisfying these transmittance and reflectance, but it may be typically 5 to 25 nm.

  The Ag-based alloy reflective film for optical information recording media of the present invention is a reflective film of a single-sided single-layer optical disk or a reflective film in the innermost recording layer of a single-sided multilayer optical disk with respect to the incident direction of laser light. The reflectance is approximately 50% or more, and the transmittance is approximately 0%. Further, the film thickness may be appropriately determined within a range satisfying these reflectance and transmittance, but it may be 50 to 250 nm as a standard.

  The Ag-based alloy semi-transmissive reflective film and reflective film for optical information recording media of the present invention are formed on a film-forming substrate by forming the above-described Ag-based alloy on a film formation substrate by various thin film forming methods such as vacuum deposition, ion plating, and sputtering. Of these thin film forming methods, those formed by sputtering are recommended. The Ag-based alloy semi-transmissive reflective film and the Ag-based alloy reflective film formed by sputtering are compared with those formed by other thin film forming methods in terms of alloy composition, alloy element distribution, and film thickness. Excellent internal uniformity and excellent performance as a semi-transmissive reflective film and reflective film (high reflectance, high transmittance, low absorption, high thermal conductivity, high cohesion resistance, high light resistance, high heat resistance) It is possible to produce an optical information recording medium that is satisfactorily exhibited and excellent in recording / reproduction characteristics and long-term reliability.

    As a sputtering target (hereinafter, also simply referred to as “target”) used when the Ag-based alloy transflective film and the reflective film of the present invention are formed by a sputtering method, 0.01 to 10% of Li is contained. By using an Ag-based alloy target, an Ag-based alloy semi-transmissive reflective film or reflective film having a desired chemical composition can be obtained. The amount of Li is 0.01 to 10%, preferably 0.05 to 8%, and more preferably 0.1 to 6%.

  Moreover, when it is going to contain 0.005-0.8% Bi further in the said Ag base alloy semi-transmissive reflective film or reflective film, it contains 0.02-8% of Bi as a target, Preferably By using an Ag-based alloy containing 0.1 to 6%, more preferably 0.2 to 4%, an Ag-based alloy semi-transmissive reflective film or reflective film having a desired chemical composition can be obtained. Here, the reason why the amount of Bi in the target is made larger than the amount of Bi in the transflective film or the reflective film is as follows. That is, when a semi-transmissive reflective film or a reflective film is formed by sputtering using a target made of an Ag-based alloy containing Bi, the amount of Bi in the semi-transmissive reflective film or the reflective film is several percent of the Bi amount in the target. It is observed that it decreases to ˜several tens of percent. This is because Bi is re-evaporated from the substrate during film formation because of the large melting point difference between Ag and Bi, and Bi is difficult to be sputtered because the sputtering rate of Ag is larger than the sputtering rate of Bi. Since Bi is more easily oxidized than Ag, only Bi is oxidized on the target surface and not sputtered. Thus, the phenomenon that the alloy element content in the semi-transmissive reflective film or the reflective film decreases from the alloy element content in the target is a phenomenon that is not seen in other Ag-based alloys such as Ag-rare earth metal alloys. is there. For this reason, the amount of Bi in the target needs to be higher than the amount of Bi in the target transflective film or reflective film.

  Further, the above-mentioned Ag-based alloy semi-transmissive reflective film or reflective film is further added with 0.1 to 2% of rare earth metal elements Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy. At least one selected from Ho, Er, Tm, Yb, and Lu, particularly when Nd and / or Y is to be contained, it is desirable to use an Ag-based alloy containing these elements in the target. An Ag-based alloy semi-transmissive reflective film or reflective film having the chemical composition can be obtained. Rare earth metal elements Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, in particular Nd and / or Y The total content is 0.1 to 2%, preferably 0.2 to 1%, and more preferably 0.3 to 0.5%.

 In addition, when the Ag-based alloy semi-transmissive reflective film or the reflective film further contains at least one selected from 0.1% to 3% of Cu, Au, Rh, Pd, and Pt, By using an Ag-based alloy containing these elements, an Ag-based alloy transflective film or reflective film having a desired chemical composition can be obtained. The total content of at least one selected from Cu, Au, Rh, Pd, and Pt is 0.1 to 3%, preferably 0.2 to 2%, more preferably 0.3 to 1%. .

  The Ag-based alloy sputtering target for optical information recording media of the present invention can be produced by any method such as a melting / casting method, a powder sintering method, or a spray forming method. Those manufactured by law are recommended. The Ag-based alloy sputtering target manufactured by the vacuum melting / casting method has a lower content of impurity components such as nitrogen and oxygen than those manufactured by other methods, and film formation is performed using this sputtering target. Excellent properties (high reflectivity, high transmittance, low absorption rate, high thermal conductivity, high cohesion resistance, high light resistance, high heat resistance) are effectively extracted in the translucent reflective film and reflective film, An optical information recording medium excellent in recording / reproducing characteristics and long-term reliability can be produced.

  The optical recording medium of the present invention is only required to include the Ag-based alloy transflective film or Ag-based alloy reflective film of the present invention, and the configuration as other optical information recording media is not particularly limited. Any configuration known in the art can be employed. For example, the above-described transflective film or reflective film made of an Ag-based alloy has high reflectivity, high transmittance, low absorption, high thermal conductivity, high aggregation resistance, high light resistance, and high heat resistance. Therefore, it can be suitably used for the current read-only, write once, and rewritable optical information recording media, as well as the next generation large recording capacity optical information recording media.

(Example)
The present invention will be described in more detail by way of experimental examples. However, the following experimental examples are not intended to limit the present invention, and modifications and implementations without departing from the spirit of the present invention are all included in the technical scope of the present invention. The
(1) Thin film sample deposition Pure Ag sputtering target (size φ101.6 mm x t5 mm), Ag-Li alloy sputtering target (size φ101.6 mm x t5 mm), Ag-Li-Bi alloy sputtering target (size φ101.6 mm x t5mm), a composite sputtering target in which a predetermined number of chips (size 5 mm × 5 mm × t1 mm) of alloy elements (Nd, Y, Cu, Au) are arranged on an Ag—Li alloy sputtering target or an Ag—Li—Bi alloy sputtering target ( DC magnetron sputtering method (back pressure: 0.27 ×) 10 ^-3 Pa or less, Ar gas pressure: 0.27 Pa, Ar gas flow rate: 30 sccm, sputtering power: DC 200 W, distance between electrodes: 52 mm, substrate temperature: the room temperature), Polycarbonate substrate (diameter: 50 mm, thickness: 1.0 mm) was formed a thin film (Sample No. 1 to 139) on. In film formation, the film thickness is set to 100 nm (corresponding to the film thickness when used as a reflective film in an optical information recording medium), analysis of the film composition described later, and aggregation resistance (aggregation caused by heat, aggregation caused by halogen) ), Heat resistance and thermal conductivity are evaluated, and the film thickness is 15 nm (the film thickness corresponding to the case where the film is used as a transflective film in an optical information recording medium). Was evaluated.
(2) Analysis of film composition Among the thin films formed as described above, the film composition of the Ag alloy thin film (sample numbers 2 to 139) was analyzed by inductively coupled plasma (ICP) mass spectrometry. Specifically, an Ag alloy thin film is used as an analysis sample, which is dissolved in an acid solution of nitric acid: pure water = 1: 1, and this acid solution is heated on a hot plate at 200 ° C. so that the analysis sample is in the acid solution. After being completely dissolved, the mixture was cooled to room temperature, and the amount of alloying elements contained in the Ag alloy thin film was measured using an ICP mass spectrometer SPQ-8000 manufactured by Seiko Instruments. The analysis results of the film composition are shown in Table 1 (sample numbers 1 to 50), Table 2 (sample numbers 51 to 100) and Table 3 (sample numbers 100 to 139)). This film composition is also shown in Tables 4 to 21 showing the evaluation results of the film characteristics described below.

(3) Evaluation of light resistance The UV-visible near-infrared spectrophotometer V-570DS manufactured by JASCO Corporation is used for the thin film (sample numbers 1 to 139) formed as described above and laminated with an ultraviolet curable resin film. Was used to measure spectral reflectance and spectral transmittance at a wavelength of 400 to 800 nm. After that, using Suga Tester's Super Xenon Fade Meter SX75F, UV / visible light irradiation (irradiation illuminance: 120 W / m ² , irradiation temperature: 80 ° C, irradiation time: 144 hours) by xenon arc lamp, After this test, spectral reflectance and spectral transmittance were measured again. Tables 4 to 6 show the evaluation results of light resistance.

  In Tables 4 to 6, when the reflectance change before and after the irradiation test of the wavelength 405 nm laser light used in Blu-ray Disc, HD DVD, etc. is less than 1%, it is regarded as having high light resistance. Those not less than 1% are regarded as not having high light resistance and are represented by x.

  From Tables 4 to 6, the Ag thin film (Sample No. 1), the Ag-Au thin film (Sample No. 2), the Ag-Pd thin film (Sample No. 3), and the Ag-Pt thin film (Sample No. 4) do not show high light resistance.

On the other hand, sample numbers 5-139 show high light resistance by containing Li. The effect of adding Rh, Pd, and Pt is the same as that of Cu and Au.
(4) Evaluation of aggregation resistance [aggregation caused by heat] The thin film (sample numbers 1 to 139) formed as described above was subjected to AFM (Atomic Force) using a Nanoscope IIIa scanning probe microscope manufactured by Digital Instruments. Microscope) The average surface roughness Ra was measured in the observation mode. The same thin film was subjected to a high-temperature and high-humidity test (temperature: 80 ° C., humidity: 90% RH, holding time: 48 hours), and the average surface roughness Ra was measured again after this test. Tables 7 to 9 show the evaluation results of the aggregation resistance [aggregation caused by heat].

  In Tables 7 to 9, when the average roughness change before and after the high-temperature and high-humidity test is less than 1.5 nm, it is considered as having high cohesion resistance, and those with 1.5 nm or more are not having high cohesion resistance It is considered as x.

As is clear from Tables 7 to 9, all the Ag alloy thin films (Sample Nos. 5 to 139) satisfying the requirements of the present invention exhibit high aggregation resistance, and the Ag thin films (Sample No. 1) that do not satisfy this, The Ag-Au thin film (Sample No. 2), the Ag-Pd thin film (Sample No. 3), and the Ag-Pt thin film (Sample No. 4) do not show high aggregation resistance. The effect of adding Rh, Pd, and Pt is the same as that of Cu and Au.
(5) Evaluation of aggregation resistance [aggregation caused by halogen] AFM (Atomic Force) was applied to the thin film (sample numbers 1 to 139) formed as described above using a Nanoscope IIIa scanning probe microscope manufactured by Digital Instruments. Microscope) The average surface roughness Ra was measured in the observation mode. The same thin film was subjected to a salt water immersion test (salt water concentration: 0.05 mol / l NaCl, salt water temperature: 20 ° C., immersion time: 5 minutes), and the average surface roughness Ra was measured again after this test. Tables 10 to 12 show the evaluation results of the aggregation resistance [aggregation caused by halogen].

  In Tables 10 to 12, when the average roughness change before and after the salt water immersion test is less than 3 nm, it is regarded as having high aggregation resistance, and when it is 3 nm or more, it is regarded as not having high aggregation resistance. It is represented by

As is clear from Tables 10 to 12, Ag-Au thin film (sample number 2), Ag-Pd thin film (sample number 3), Ag-Pt thin film (sample number 4), and Ag satisfying the requirements of the present invention All of the alloy thin films (Sample Nos. 5 to 139) exhibit high aggregation resistance, and the Ag thin film (Sample No. 1) not satisfying this does not exhibit high aggregation resistance. The effect of adding Rh, Pd, and Pt is the same as that of Cu and Au.
(6) Evaluation of heat resistance The thin film (sample numbers 1 to 139) formed as described above is averaged by AFM (Atomic Force Microscope) observation mode using a Nanoscope IIIa scanning probe microscope manufactured by Digital Instruments. The roughness Ra was measured. The same thin film was subjected to vacuum heating (vacuum degree: 0.27 × 10 ^-3 Pa or less, temperature: 300 ° C., holding time: 0.5 hour) using a rotating magnetic field heat treatment device manufactured by Naruse Scientific Instruments. After the test, the average surface roughness Ra was measured again. The evaluation results of heat resistance are shown in Tables 13-15.

  In Tables 13 to 15, when the average roughness change before and after the vacuum heating test is less than 1.5 nm, it is regarded as having excellent heat resistance, and from 1.5 nm to less than 3.0 nm has high heat resistance. Assuming that ○ or 3.0 nm or more is regarded as not having high heat resistance, x is represented.

  The Ag thin film (Sample No. 1), the Ag-Au thin film (Sample No. 2), the Ag-Pd thin film (Sample No. 3), and the Ag-Pt thin film (Sample No. 4) do not show high heat resistance.

On the other hand, sample numbers 5 to 139 show high heat resistance. Particularly those containing Nd and / or Y exhibit excellent heat resistance. The effect of adding Rh, Pd, and Pt is the same as that of Cu and Au.
(7) Evaluation of reflectance, transmittance, and absorptivity For the thin film (sample numbers 1 to 139) formed as described above, the wavelength was measured using a UV-visible near-infrared spectrophotometer V-570DS manufactured by JASCO Corporation. Spectral reflectance and spectral transmittance at 400-800 nm were measured. In addition, an absorptance (= 100% − (reflectance + transmittance)) was calculated from the measured reflectivity and transmittance. Tables 16 to 18 show the evaluation results of reflectance, transmittance, and absorptance with respect to a 405 nm wavelength laser beam used in Blu-ray Disc, HD DVD, and the like.

  In Tables 16-18, it is excellent that the reflectivity is 15% or more, the transmittance is 60% or more, and the absorptivity is less than 25% with respect to the reflectivity of 18%, the transmittance of 68% and the absorption of 14% of the pure Ag thin film O, and those showing a reflectance of less than 15%, a transmittance of less than 60%, and an absorptance of 25% or more are regarded as having no excellent optical properties and are represented by x.

  Since the Ag-16% Li thin film (Sample No. 8) has a large Li content, it does not exhibit high reflectance, high transmittance, or low absorption.

On the other hand, other thin films exhibit high reflectance, high transmittance, and low absorption. The effect of adding Rh, Pd, and Pt is the same as that of Cu and Au.
(8) Evaluation of thermal conductivity About the thin film (sample numbers 1-139) formed into a film as mentioned above, thermal conductivity was measured with the following method. Measure sheet resistance Rs by DC four-probe method using 3226 mΩ Hi TESTER manufactured by Hioki Electric, and film thickness t using alpha-step 250 manufactured by TENCOR INSTRUMENTS. Electric resistivity ρ (= sheet resistance Rs × After calculating the film thickness t) [μΩcm], the thermal conductivity κ (= 2.51 × absolute temperature T / electric resistivity ρ) [W / (m) at an absolute temperature of 300 K (≈27 ° C.) according to Wiedemann-Franz law -K)] was calculated. The evaluation results of thermal conductivity are shown in Tables 19-21.

  In Tables 19 to 21, when the thermal conductivity of the pure Ag thin film is 160 W / (m · K) corresponding to 50% or more of the thermal conductivity of 320 W / (m · K), it is regarded as having high thermal conductivity. Those showing less than 160 W / (m · K) are regarded as not having high thermal conductivity and are represented by ×.

  The Ag-16% Li thin film (Sample No. 8) does not show high thermal conductivity because of its high Li content.

On the other hand, other thin films exhibit high thermal conductivity. The effect of adding Rh, Pd, and Pt is the same as that of Cu and Au.

Claims (6)

While containing 0.01 to 10 atomic% of Li ,
At least one selected from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu in a total of 0.1 to 2 atomic%, and / or An Ag-based alloy transflective film or reflective film for optical information recording media, which is an Ag-based alloy containing a total of 0.1 to 3 atomic% of at least one selected from Au, Rh, and Pb .   The Ag-based alloy transflective film or reflective film for optical information recording media according to claim 1, wherein Bi is contained in an amount of 0.005 to 0.8 atomic%. An optical information recording medium comprising the Ag-based alloy transflective film according to claim 1. An optical information recording medium comprising the Ag-based alloy reflective film according to claim 1. While containing 0.01 to 10 atomic% of Li,
At least one selected from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu in a total of 0.1 to 2 atomic%, and / or An Ag-based alloy sputtering target for optical information recording media, characterized in that it is an Ag-based alloy containing a total of 0.1 to 3 atomic% of at least one selected from Au, Rh, and Pb. The Ag-based alloy sputtering target for optical information recording media according to claim 5, which contains Bi in an amount of 0.005 to 0.8 atomic%.