JP2014218737A - Oxide sputtering target and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxide sputtering target for forming an optical recording medium protective film, capable of forming a film that has high preservability, is flexible and hardly cracked, capable of direct-current sputtering, and having few particles.SOLUTION: An oxide sputtering target is an oxide sintered body having a composition in which Sn:7 at% or more and In:0.1-35.0 at% are contained with respect to the total metal component content, the residue comprises Zn and inevitable impurities, the inclusion atomic ratio Sn/(Sn+Zn) of Sn and Zn is 0.5 or less, and ZnSnOhaving solid-dissolved In is a main phase.

Description

  The present invention relates to an oxide sputtering target for forming a protective film for an optical recording medium used for, for example, a Blu-ray Disc (registered trademark: hereinafter referred to as BD) and a method for manufacturing the same.

  In recent years, with the improvement of the picture quality of photographs and moving images, digital data when recording on an optical recording medium or the like has increased, and there has been a demand for an increase in the capacity of the recording medium. Depending on the system, BDs with a capacity of 50 GB are sold. In the future, it is desired to further increase the capacity of this BD, and research on increasing the capacity by increasing the number of recording layers has been actively conducted.

JP 2009-26378 A JP 2005-228402 A JP 2005-154820 A

Here, the conventional technique will be described below with reference to the above-mentioned patent document.
In the recording medium of the type using an organic dye for the recording layer, since the deformation of the recording layer due to laser irradiation at the time of recording is large as compared with the case where an inorganic substance is used as the recording layer, it is also described in Patent Document 1. Thus, a low hardness is required for the protective layer adjacent to the recording layer. Therefore, conventionally, ZnS—SiO ₂ or ITO, which is a film having an appropriate hardness, is employed for the protective layer.

However, when ZnS-SiO ₂ is employed, as described in Patent Document 2, since sulfur (S) is contained, this sulfur reacts with the metal in the reflective film, There is a disadvantage that the reflectance of the reflective film is lowered and the storage stability as a recording medium is low. In addition, in the case of ITO, many particles are generated during sputtering, which adversely affects the recording characteristics and storability of the disc. Therefore, it is necessary to frequently clean the production equipment, resulting in poor productivity. there were. Further, Patent Document 3 proposes a sputtering target mainly composed of tin oxide, zinc oxide, and an oxide of a trivalent or higher element having a tin oxide phase as a main phase. There was a problem that the tin oxide phase inside caused nodules, which led to the generation of particles.
As described above, there are problems in the conventional technology, and problems remain.

  The present invention has been made in view of the above-mentioned problems, and can form a film that is highly storable as a recording medium, is soft and hardly cracked, and is formed by direct current (DC) sputtering. It is an object of the present invention to provide an oxide sputtering target and a method for manufacturing the same.

The inventors have conducted research on a ZnO-based sputtering target mainly composed of tin oxide (SnO ₂ ), zinc oxide (ZnO), and an oxide of a trivalent or higher element. When indium oxide (In ₂ O ₃ ) is added as an oxide of a trivalent or higher element and pressure-sintered in a non-oxidizing atmosphere, a Zn ₂ SnO ₄ phase in which In is dissolved is generated, and some oxygen Since the specific resistance of the target itself can be further reduced by the occurrence of defects, stable direct current (DC) sputtering is possible, and when sputtering using this sputtering target, no sulfur component is contained. Sn-In-Zn-O quaternary oxidation that can suppress the influence on the reflectivity of the laminated reflective layer, has high storage stability, and is soft and difficult to break It is finding that a film can be formed was obtained.

Therefore, the present invention adopts the following configuration in order to solve the above-described problems based on the above knowledge.
(1) The oxide sputtering target of the present invention contains Sn: 7 at% or more and In: 0.1-35.0 at% with respect to the total amount of metal components, with the balance being Zn and inevitable impurities. , An oxide sintered body having a composition in which the atomic ratio Sn / (Sn + Zn) of Sn and Zn is 0.5 or less, and the oxide sintered body is composed of Zn ₂ SnO _{4 in} which In is a solid solution. It is characterized by having an organization.
(2) The oxide sputtering target of the present invention contains Sn: 7 at% or more and In: 0.1-35.0 at% with respect to the total amount of metal components, and 1 of Ge and Cr. Total of at least seeds: 1.0 to 30.0 at%, the balance is made of Zn and inevitable impurities, the atomic ratio Sn / (Sn + Zn) of Sn and Zn is 0.5 or less, and The oxide sintered body has a composition in which the atomic ratio of Sn, Cr, Ge, Zn (Sn + Cr + Ge) / (Sn + Cr + Ge + Zn) is 0.6 or less, and the oxide sintered body is Zn ₂ in which In is dissolved. It has a structure having SnO ₄ as a main phase.
(3) The method for producing an oxide sputtering target of the present invention is the method for producing an oxide sputtering target according to (1) above, wherein SnO ₂ powder, In ₂ O ₃ powder, and ZnO powder are mixed and mixed. The mixed powder thus obtained is subjected to pressure firing at a temperature of 800 to 1100 ° C. in a vacuum or an inert gas for 2 to 9 hours.
(4) The method for producing an oxide sputtering target according to the present invention is the method for producing the oxide sputtering target according to (2) above, wherein SnO ₂ powder, In ₂ O ₃ powder, and ZnO powder are blended, Furthermore, the mixed powder obtained by blending and mixing one or more of Cr ₂ O ₃ powder and GeO ₂ powder is heated for 2 to 9 hours at a temperature of 800 to 1100 ° C. in vacuum or in an inert gas. It is characterized by pressure firing.
(5) The protective film for an optical recording medium of the present invention is formed by sputtering using the oxide sputtering target of (1) above, and Sn: 7 at% or more with respect to the total metal component amount, In: 0.0. 1 to 35.0 at%, and the balance is made of Zn and inevitable impurities.
(6) The protective film for an optical recording medium of the present invention is formed by sputtering using the oxide sputtering target of (2) above, and Sn: 7 at% or more with respect to the total metal component amount, In: 0.0. 1 to 35.0 at%, and a total of one or more of Ge and Cr: 1.0 to 30.1 at%, and the balance is an oxide having a component composition consisting of Zn and inevitable impurities. It is characterized by being.

This oxide sputtering target contains Sn: 7 at% or more and In: 0.1-35.0 at% with respect to the total amount of metal components, and the balance consists of Zn and inevitable impurities. The atomic ratio R1: Sn / (Sn + Zn) is an oxide sintered body having a component composition of 0.5 or less, and this oxide sintered body has Zn ₂ SnO _{4 in} which In is dissolved as a main phase. Therefore, it has a low specific resistance, enables stable direct current (DC) sputtering, has little influence on the reflectivity, and can form a soft and hard-to-break film, which is highly preserved as a recording medium. You can expect sex.
Note that in the oxide sintered body, a structure having Zn ₂ SnO _{4 in} which In having a low specific resistance is dissolved as a main phase is used, so that either or both of zinc oxide having a high specific resistance and Zn ₂ SnO ₄ are used. The specific resistance of the sputtering target itself can be lowered as compared with the structure having a main phase of, so that abnormal discharge during sputtering and generation of particles can be suppressed, and direct current (DC) sputtering can be stabilized.

Here, the reason why the content of In is 0.1 to 35.0 at% is that when it is less than 0.1 at%, direct current (DC) sputtering becomes unstable, and the formed film is not cracked. This is because it tends to occur. Then, the content of In is more than 35.0At%, a portion of the indium oxide in the tissue _(In 2 _{O 3)} is reduced, there is a possibility that metallic indium (In) is eluted. If this In is eluted, In will adhere to the furnace during production, causing damage to the furnace, as well as reducing productivity due to cleaning in the furnace, and further sputtering by the eluted In. The compositional variation of the target becomes a problem.
The content of In is more preferably 8 at% or more and 20 at%.

The reason why the Sn content is 7 at% or more is that if it is less than 7 at%, the hardness (indentation hardness) of the formed film becomes 800 mgf / μm ² or more, and it becomes hard. is there. Furthermore, regarding the Sn content, the reason why the atomic ratio R1: Sn / (Sn + Zn) between Sn and Zn is 0.5 or less is that when this ratio exceeds 0.5, there is too much Sn, Since a lot of tin oxide (SnO ₂ ) phase remains in the structure of the sputtering target and may cause particles and abnormal discharge during sputtering, it may be difficult to realize more stable sputtering. From the same viewpoint, the Sn content is desirably 46 at% or less, and more desirably 25 to 46 at%. Furthermore, the atomic ratio R1: Sn / (Sn + Zn) of Sn and Zn is preferably 0.08 or more, and more preferably 0.3 to 0.5.

Furthermore, when one or more of Cr and Ge are blended, film peeling from the chamber can be suppressed. Regarding the content of Sn, Cr, Ge, the reason why the atomic ratio R2: (Sn + Cr + Ge) / (Sn + Cr + Ge + Zn) = 0.6 or less is that if it exceeds 0.6, the tin oxide phase, chromium oxide in the target structure Since a large amount of germanium oxide remains, causing particles and abnormal discharge, it may be difficult to realize more stable sputtering. The atomic ratio R2: (Sn + Cr + Ge) / (Sn + Cr + Ge + Zn) is preferably 0.08 or more, and more preferably 0.3 to 0.6.
Further, when the Cr content exceeds 30 at%, abnormal discharge increases, and when the Ge content also exceeds 30 at%, abnormal discharge increases, so the Cr content is 30 at% or less, And it is preferable to make content of Ge into 30 at% or less.
In addition, when Cr or Ge is added, the Cr or Ge content is preferably 1.0 at% or more, more preferably Cr content, in order to reliably suppress film peeling from the chamber. Is 1.0 to 10.0 at%, and the Ge content is 1.0 to 10.0 at%.

Further, in the method of manufacturing an oxide sputtering target according to the present invention, the SnO ₂ powder, an In ₂ O ₃ powder and a mixed powder obtained by mixing and blending the ZnO powder, in a vacuum or in an inert gas, Since pressure firing was performed at a temperature of 800 to 1100 ° C. for 2 to 9 hours, Sn: 7 at% or more and In: 0.1 to 35.0 at% with respect to the total amount of metal components In addition, an oxide sintered body having a composition in which the balance is made of Zn and inevitable impurities and the Sn / Zn content atomic ratio R1: Sn / (Sn + Zn) is 0.5 or less can be produced. It has a structure whose main phase is Zn ₂ SnO _{4 in} which In is dissolved. By setting it as such a structure, the specific resistance of a sputtering target can be made still lower and stable direct current (DC) sputtering becomes possible.

In another method of manufacturing an oxide sputtering target according to the present invention, SnO ₂ powder, In ₂ O ₃ powder, and ZnO powder are blended, and at least one of Cr ₂ O ₃ powder and GeO ₂ powder is blended. The mixed powder obtained by blending and mixing is pressure baked in vacuum or in an inert gas at a temperature of 800 to 1100 ° C. for 2 to 9 hours. For this reason, it contains Sn: 7 at% or more and In: 0.1 to 35.0 at% with respect to the total metal component amount, and furthermore, a total of one or more of Ge and Cr: 1.0 to 30.0 at%, the balance is made of Zn and inevitable impurities, the atomic ratio R1: Sn / (Sn + Zn) of Sn and Zn is 0.5 or less, and Sn, Cr, Ge, Zn Contained atomic ratio R2: An oxide sintered body having a composition of (Sn + Cr + Ge) / (Sn + Cr + Ge + Zn) of 0.6 or less can be produced, and the oxide sintered body is composed of Zn ₂ SnO _{4 in} which In is dissolved. It will have the organization that. By setting it as such a structure, the specific resistance of a sputtering target can be made still lower and stable direct current (DC) sputtering becomes possible.

  As described above, when a film is formed by direct current (DC) sputtering using the manufactured oxide sputtering target, a soft and hard-to-break film can be formed, and the influence on the reflective layer can be suppressed. Therefore, the formed film is suitable as a protective film for BD using an organic dye recording layer.

The oxide sputtering target according to the present invention contains Sn: 7 at% or more and In: 0.1-35.0 at% with respect to the total amount of metal components, with the balance being Zn and inevitable impurities. And the atomic ratio R1: Sn / (Sn + Zn) of the component composition of Sn and Zn is 0.5 or less, or a total of one or more of Ge and Cr: 1 0.0 to 30.0 at%, Sn: Zn atomic ratio R1: Sn / (Sn + Zn) is 0.5 or less, and Sn, Cr, Ge, Zn atomic ratio R2 :( Since the oxide sintered body having a composition in which Sn + Cr + Ge) / (Sn + Cr + Ge + Zn) is 0.6 or less has a structure whose main phase is Zn ₂ SnO _{4 in} which In is dissolved, the specific resistance of the target itself is further reduced. Stable DC DC) is made possible sputtering.

  Further, when sputtering is performed using the oxide sputtering target of the present invention, Sn: 7 at% or more and In: 0.1-35.0 at% with respect to the total amount of metal components, the balance being Zn and inevitable A Sn—In—Zn—O quaternary oxide film which is an impurity and has a component composition in which the atomic ratio R1: Sn / (Sn + Zn) of Sn and Zn is 0.5 or less; And the total of one or more of Cr: 1.0 to 30.0 at%, the atomic ratio R1: Sn / (Sn + Zn) of Sn and Zn is 0.5 or less, and Sn, Cr , Ge, Zn content atomic ratio R2: (Sn + Cr + Ge) / (Sn + Cr + Ge + Zn) Sn—In—Zn—O quaternary having one or more of Cr and Ge having a component composition of 0.6 or less Oxide film It can deposition, moreover, obtained soft cracking hardly film, having a high storage stability as a recording medium. Therefore, the oxide film formed by the oxide sputtering target of the present invention is suitable as a dielectric protective film for BD using an organic dye recording layer.

In the Example of the oxide sputtering target which concerns on this invention, and the protective film for optical recording media, it is the element distribution image of each element which measured the cross-sectional structure | tissue of the oxide sputtering target by EPMA. It is a graph which shows the analysis result of the X-ray diffraction (XRD) of the sputtering target for transparent oxide film formation which concerns on an Example. It is a graph which shows the analysis result of the X-ray diffraction (XRD) of the sputtering target for transparent oxide film formation concerning a comparative example.

  Hereinafter, embodiments of the oxide sputtering target and the manufacturing method thereof according to the present invention will be specifically described with reference to examples.

〔Example〕
The oxide sputtering target of this example is a sputtering target for producing a dielectric protective film laminated on a recording layer formed of an organic dye in BD, for example, Sn: 7 at% or more, and In: 0.1 to 35.0 at%, the balance is made of Zn and inevitable impurities, and the atomic ratio R1: Sn / (Sn + Zn) of Sn and Zn is set to 0.5 or less. Or a total of one or more of Ge and Cr: 1.0 to 30.0 at%, and an atomic ratio of Sn and Zn R1: Sn / (Sn + Zn) Is an oxide sintered body having a composition in which the atomic ratio R2 of Sn, Cr, Ge, Zn: (Sn + Cr + Ge) / (Sn + Cr + Ge + Zn) is 0.6 or less.
Note that, since an oxide sputtering target generally exhibits insulating properties, when sputtering is performed with this, high frequency (RF) sputtering is used, and direct current (DC) sputtering is difficult to perform. Therefore, in order to be able to perform direct current (DC) sputtering with an oxide sputtering target, it is desirable that the specific resistance of the sputtering target itself be 1 Ω · cm or less. In particular, in order to perform stable sputtering with less abnormal discharge, the specific resistance is desirably 0.1 Ω · cm or less, and further 0.01 Ω · cm or less.

Therefore, in the method of manufacturing an oxide sputtering target according to this example, Sn: 7 at% or more and In: 0.1-35.0 at% with respect to the total metal component amount, with the balance being Zn and inevitable. An oxide sintered body comprising impurities and having a composition of Sn: Zn containing atomic ratio R1: Sn / (Sn + Zn) of 0.5 or less, or a total of at least one of Ge and Cr: 1 0.0 to 30.0 at%, Sn: Zn atomic ratio R1: Sn / (Sn + Zn) is 0.5 or less, and Sn, Cr, Ge, Zn atomic ratio R2 :( Sn + Cr + Ge) / ( Sn + Cr + Ge + Zn) of the composition is 0.6 or less oxide sintered body, in order to produce an oxide sputtering target containing in has a main phase of _Zn 2 SnO ₄ was dissolved tissue, acid Zinc (chemical _{formula: ZnO, D 50 = 1μm)} , tin oxide (chemical _{formula: SnO 2, D 50 = 16μm} ), indium oxide (chemical _{formula: In 2 O 3, D 50} = 11μm), germanium oxide (chemical formula: _GeO 2, D ₅₀ = 1.0 μm) and chromium oxide (chemical formula: Cr ₂ O ₃ , D ₅₀ = 0.4 μm) were prepared as raw material powders, and each raw material powder was weighed at a predetermined ratio shown in Table 1.
As the content of the raw powder, the total of both when SnO ₂ powder 7~48mol%, _In 2 _{O 3} powder is 0.1 to 20 mol%, further containing _Cr 2 _{O 3} powder and GeO ₂ powder : Less than 33 mol%, and it is preferable to adjust so that the remainder becomes ZnO powder.

The weighed raw material powder and 3 times its amount (weight ratio) of zirconia balls (diameter 5 mm) were placed in a plastic container and wet mixed in a ball mill apparatus for 24 hours. In addition, alcohol was used for the solvent in this case, for example. Next, after drying the obtained mixed powder, it is granulated, and 800-1100 ° C., preferably 900-1000 ° C., 2-9 hours at a pressure of 100-500 kgf / cm ² , vacuum or non- Hot pressing was performed in an active gas atmosphere to prepare sputtering targets of Examples 1 to 21. The target size was 125 mm diameter x 5 mm thickness. In addition, although pressurization sintering was performed by hot press, you may employ | adopt HIP method (hot isostatic press-type sintering method) etc. as another method.

[Comparative Example]
A comparative example was prepared for comparison with the examples. In Comparative Example 1, no indium oxide (In ₂ O ₃ ) powder was used as the raw material powder. In Comparative Examples 2 to 7, the prepared oxide sputtering target was out of the composition range of the present invention. Specifically, oxide sputtering targets of Comparative Examples 1 to 7 were produced at the blending ratio shown in Table 1. For reference, a sputtering target (Comparative Example 8) made of 80 mol% ZnS and 20 mol% SiO ₂ and a sputtering target made of ITO (Comparative Example 9) were prepared.

  Next, Table 2 shows the results of analyzing the metal component composition by ICP for the oxide sputtering targets of Examples 1 to 21 and Comparative Examples 1 to 7 manufactured above. In Table 2, R1 is the atomic ratio Sn / (Sn + Zn) of Sn and Zn, and R2 is the atomic ratio of Sn, Cr, Ge (Sn + Cr + Ge) / (Sn + Cr + Ge + Zn). Here, each element symbol represents the content (at%), and when the element is not included, the content of the element is 0 at%, and the content atomic ratio is calculated.

  Next, using these oxide sputtering targets of Examples 1 to 21 and Comparative Examples 1 to 9, Sn-In-Zn-O quaternary as a protective film for an optical recording medium under the following film forming conditions. A system oxide film was formed to prepare oxide films of Examples 1 to 21 and Comparative Examples 1 to 9. Table 3 shows the results of analyzing the metal component composition of these oxide films. The content ratios R1 and R2 in Table 3 were calculated from the content (at%) of each element in the same manner as in Table 2.

<Film formation conditions>
・ Power supply: DC1000W (partly, high frequency (RF) sputtering)
・ Total pressure: 0.4Pa
Sputtering gas: Ar = 47.5 sccm, 0 ₂ : 2.5 sccm
・ Target-to-board (TS) distance: 70mm

  Next, for the oxide sputtering targets of Examples 1 to 21 and Comparative Examples 1 to 9, the density ratio, the specific resistance, the presence or absence of elution of In, and when sputtering was performed using those oxide sputtering targets The number of abnormal discharges and the amount of particles were evaluated. Furthermore, regarding the oxide film obtained by the sputtering, the indentation hardness of the film, the cracking of the film, and the change in reflectance were determined. These results are shown in Tables 4 and 5. The evaluation / measurement methods used here are as follows.

<Density ratio measurement>
The density ratio was calculated by machining the sintered body to a predetermined size, measuring the weight, obtaining the bulk density, and then dividing by the theoretical density ρ _fn . The theoretical density ρ _fn was determined by the following formula based on the weight of the raw material.

<Specific resistance measurement>
The specific resistance of the oxide sputtering target and the oxide film was measured using a 4-probe resistivity meter RT-70 manufactured by Napson Corporation. When it was not possible to measure with the measuring instrument, it was described as “out of measurable range”.

<Number of abnormal discharge>
Sputtering was performed for 2 hours under the above conditions, and the number of abnormal discharges (number of times / hour) was measured. Thereafter, the sputtering chamber was released and particles in the chamber were confirmed. In the case of the oxide sputtering target of Comparative Example 8, since direct current (DC) sputtering could not be performed, it was described as “DC sputtering impossible” and the film formation was performed by high frequency sputtering.

<Elution of In>
In elution was confirmed by visual inspection and XRD after target sintering.

<Target XRD>
Preparation of sample: The sample was wet-polished with SiC-Paper (grit 180) and dried, and then used as a measurement sample. XRD was performed under the following conditions. Table 4 shows 2θ indicating the main phase and (440) reflection of Zn ₂ SnO ₄ obtained as a result.
Equipment: Rigaku Corporation (RINT-Ultima / PC)
Tube: Cu (CuKα1)
Tube voltage: 40kW
Tube current: 40 mA
Scanning range (2θ): 5 ° -80 °
Slit size: Divergence (DS) 2/3 degrees, Scattering (SS) 2/3 degrees, Light reception (RS) 0.8mm
Measurement step width: 0.02 degrees at 2θ Scan speed: 2 degrees per minute Sample stage rotation speed: 30 rpm

<Particle>
Pre-sputtering was performed under the above conditions to remove the target surface processed layer, and then the chamber was once opened to the atmosphere to clean the chamber members such as the deposition preventive plate. Thereafter, evacuation was performed again, and after evacuation, pre-sputtering for 30 minutes was performed to remove atmospheric adsorption components on the target surface, and then a film having a thickness of 100 nm was formed on a 4-inch Si wafer. A total of 25 films were formed under the same conditions, and the number of particles of 1.0 μm or more adhering to the wafer surface was measured with a commercially available foreign substance inspection apparatus for the wafers after film formation, and the average value of 25 sheets was calculated. In Table 4, “◎” indicates that the number of particles is 20 or less, “◯” indicates that the number is 21 to 50, “Δ” indicates that the number is 51 to 200, and “×” indicates that the number is 201 or more. It was written.

<Indentation hardness of film>
Under the above-mentioned conditions, the substrate was formed as 1737 glass made by Corning, the film thickness was 500 nm, the indentation load was 35 mgf, and the measurement was performed with an ultra-fine indentation hardness tester (ENTION 1100a made by Elionix). . The substrate was set in a 27 ° C. apparatus and measured after 1 hour or more had elapsed. In addition, the average value of 10-point measurement was made into the measured value.

<Membrane cracking>
Under the above-mentioned conditions, a film of 100 nm was formed on a PET film having a thickness of 0.1 mm, the film was bent 10 times, and then the surface of the film was observed with a microscope at a magnification of 1000 to check for cracks. .

<Change in reflectance>
A substrate in which an Ag _98.1 Nd _1.0 Cu _0.9 alloy was sputtered on a polycarbonate and the following dye was formed was used, and the oxide films of the examples and comparative examples (protection) under the above-mentioned conditions on the substrate. Film) was formed to a thickness of 14 nm. Then, it was left to stand in a constant temperature and humidity chamber at 80 ° C. and 85% for 100 hours, and the change in reflectance before and after that was measured. In addition, the ultraviolet visible spectrophotometer (JASCO Corporation V-550) was used for the measurement of a reflectance. Moreover, the reflectance with respect to the light of wavelength 405nm was calculated | required.

Dye:
The dye formed on the substrate includes, for example, a compound having a coupler component having a 6-hydroxy-2-pyridone structure and a diazo component of isoxazole triazole as an azo dye, and the organic dye compound. A metal complex compound composed of a metal ion, and a mixture solution obtained by diluting the compound having the coupler component and the diazo component with octafluoropentanol (OFP) to 1.0% by weight is formed by spin coating. Filmed.

As can be seen from the results shown in Table 4 above, the sputtering targets of Examples 1 to 21 all have a specific resistance of 0.1 Ω · cm or less, can perform direct current sputtering, and the number of abnormal discharges is extremely high. It was confirmed that there was little, and in any case, no elution of In was observed, and it was also confirmed that Zn ₂ SnO ₄ in which In was dissolved was the main phase.
On the other hand, in the sputtering target of Comparative Example 1, Zn ₂ SnO ₄ was the main phase, but it did not contain In, had a high specific resistance, and abnormal discharge occurred frequently. In Comparative Example 2, it was confirmed that since In ₂ O ₃ was mixed in a large amount, In was eluted and it was unsuitable for producing an oxide sputtering target. In the sputtering target of Comparative Example 3, since the ratio R1 of the In and Sn contents was too small, Zn ₂ SnO ₄ in which In was dissolved did not become the main phase. In the sputtering target of Comparative Example 4, since SnO ₂ was blended too much, SnO ₂ became the main phase, and Zn ₂ SnO ₄ in which In was dissolved did not become the main phase. In the sputtering targets of Comparative Examples 5 to 7, there was no elution of In and Zn ₂ SnO ₄ in which In was dissolved was the main phase, but both had high specific resistance, frequent abnormal discharges, and DC sputtering. Was found to be inappropriate.

As for the oxide film (protective film) formed, as can be seen from the results shown in Table 5 above, when the film was formed by DC sputtering using the sputtering targets of Examples 1 to 21 In any case, it was confirmed that a film that was soft and difficult to break and had a small change in reflectance was obtained.
On the other hand, in the case of Comparative Example 1, the indentation hardness value of the film was high, and the film was cracked, so that a soft film suitable for the protective film could not be obtained. In Comparative Examples 3 and 4, although the film did not crack, the indentation hardness value of the film was high, and a soft film suitable for the protective film could not be obtained.

As described above, according to the oxide sputtering target of each of the above examples, the oxide sintered body has a structure whose main phase is Zn ₂ SnO _{4 in} which In is dissolved, and the specific resistance of the target itself. It was confirmed that stable direct current (DC) sputtering was possible. In addition, it was confirmed that a Sn—In—Zn—O quaternary oxide film could be formed by direct current sputtering using the oxide sputtering target of each example, and that a soft and hard-to-break film could be obtained. Therefore, the oxide film formed with the oxide sputtering target of the present invention is suitable as a dielectric protective film for BD using an organic dye recording layer, and has high storage stability as a recording medium. .

Next, the results of X-ray diffraction (XRD) of the sputtering targets of Example 1 and Comparative Example 1 of the present invention are shown in FIG. 2 and FIG. As can be seen from this result, in the example of the present invention, a diffraction peak attributed to ZnO and a diffraction peak attributed to Zn ₂ SnO ₄ , which is a composite oxide of SnO ₂ and ZnO, were detected (Powder Diffraction File). No. 74-2184), the presence of ZnO and Zn ₂ SnO ₄ phases was confirmed. In Example 1, it was confirmed that the diffraction peak of Zn ₂ SnO ₄ was shifted to the low angle side due to the solid solution of In.

Further, with respect to the sputtering target of Example 1, a reflected electron image (CP) and an element distribution image showing the composition distribution of each element were observed with EPMA (Field Emission Electron Beam Probe). The reflected electron image and element distribution image are shown in FIG.
The element distribution image by EPMA is originally a color image, but is described after being converted into a black and white image, and thus a light and dark portion (relatively white portion) is a portion where the concentration of the predetermined element is high. .
From these images, it can be seen that the sputtering target of Example 1 is composed of a phase of ZnO and Zn ₂ SnO ₄ and In is very uniformly dispersed in the Zn ₂ SnO ₄ phase.

  In order to use the present invention as a sputtering target, the surface roughness is 5.0 μm or less, more preferably 1.0 μm or less, the particle size is 20 μm or less, more preferably 10 μm or less, and the metal impurity concentration is 0.00. 1 atomic% or less, more preferably 0.05 atomic% or less, bending strength: 50 MPa or more, more preferably 100 MPa or more. Each of the above-described embodiments satisfies these conditions.

The technical scope of the present invention is not limited to the above-described embodiment and examples, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment and the above examples, pressure sintering is performed by hot pressing, but as another method, a HIP method (hot isostatic pressing method) or the like may be employed.

Claims (6)

Sn: 7 at% or more and In: 0.1 to 35.0 at% with respect to the total amount of metal components, the balance is made of Zn and inevitable impurities, and the atomic ratio of Sn and Zn Sn / (Sn + Zn ) Is an oxide sintered body having a composition of 0.5 or less,
The oxide sintered body is characterized in that the oxide sintered body has a structure whose main phase is Zn ₂ SnO _{4 in} which In is dissolved. It contains Sn: 7 at% or more and In: 0.1-35.0 at% with respect to the total amount of metal components. Furthermore, the total of one or more of Ge and Cr: 1.0-30.0 at %, The balance is made of Zn and inevitable impurities, the atomic ratio Sn / (Sn + Zn) of Sn and Zn is 0.5 or less, and the atomic ratio of Sn, Cr, Ge, Zn (Sn + Cr + Ge) ) / (Sn + Cr + Ge + Zn) is an oxide sintered body having a composition of 0.6 or less,
The oxide sintered body is characterized in that the oxide sintered body has a structure whose main phase is Zn ₂ SnO _{4 in} which In is dissolved. A method of manufacturing an oxide sputtering target according to claim 1, and SnO ₂ powder, and In ₂ O ₃ powder, a mixed powder obtained by mixing and blending the ZnO powder, vacuum or inert The manufacturing method of the oxide sputtering target characterized by carrying out pressure baking for 2 to 9 hours at the temperature of 800-1100 degreeC in gas. A method of manufacturing an oxide sputtering target according to claim 2, and SnO ₂ powder was blended with _In 2 _{O 3} powder and ZnO powder, further, _Cr 2 _{O 3} of the powder and GeO ₂ powder 1 Production of oxide sputtering target characterized in that mixed powder obtained by blending and mixing seeds or more is subjected to pressure firing in vacuum or inert gas at a temperature of 800 to 1100 ° C. for 2 to 9 hours Method. Sputtered using the oxide sputtering target according to claim 1,
A protective film for an optical recording medium, comprising Sn: 7 at% or more and In: 0.1-35.0 at% with respect to the total amount of metal components, the balance being made of Zn and inevitable impurities. Sputtered using the oxide sputtering target according to claim 2,
It contains Sn: 7 at% or more and In: 0.1-35.0 at% with respect to the total metal component amount, and further, a total of one or more of Ge and Cr: 1.0-30.1 at %, And the balance is an oxide having a component composition consisting of Zn and inevitable impurities.