KR20070022764A - Sputtering target, optical information recording medium and method for producing same - Google Patents

Abstract

A sputtering target, comprising a material mainly composed of Y ₂ O ₃ , Al ₂ O _3, and SiO ₂ , and forming part of the structure of the optical information recording medium as at least a thin film by using the sputtering target; An optical information recording medium and a method of manufacturing the same, wherein the optical information recording medium is disposed adjacent to the recording layer or the reflective layer. A thin film for an optical information recording medium having stable film amorphousness, good adhesion to a recording layer, excellent mechanical properties, high transmittance, and a non-emulsification system, which are less likely to cause deterioration of adjacent reflective layers and recording layers. (Particularly used as a protective film), and a method of manufacturing the same and a sputtering target applicable to them, which aims to greatly improve the characteristics and productivity of the optical information recording medium.

Optical information green medium, sputtering target

Description

Sputtering target, optical information recording medium and manufacturing method thereof {SPUTTERING TARGET, OPTICAL INFORMATION RECORDING MEDIUM AND METHOD FOR PRODUCING SAME}

In the present invention, the amorphous property of the sputter film is stabilized, the adhesion with the recording layer is excellent, the mechanical properties are excellent, the transmittance is high, and it is composed of a non-emulsion system so that the adjacent reflection A thin film for an optical information recording medium (especially used as a protective film), a method of manufacturing the same, and a sputtering target applicable to these layers and recording layers, which are unlikely to deteriorate.

Conventionally, ZnS-SiO _2, which is generally used for the protective layer of the phase change type optical information recording medium, has excellent characteristics in optical properties, thermal properties, adhesion to the recording layer, and is widely used.

However, the rewritable DVDs represented by Blu-Ray are required to increase the number of times of writing again, to increase the capacity, and to record at high speed.

One of the causes of the deterioration of the number of times of rewriting of the optical information recording medium, etc., is the diffusion of sulfur components from ZnS-SiO ₂ to the recording layer material disposed as if sandwiched in the protective layer ZnS-SiO ₂ . have.

In addition, pure Ag or Ag alloys having high heat conductivity and high thermal conductivity for high capacity and high-speed recording have been used as reflective layer materials, but such reflective layers also come into contact with the protective layer material ZnS-SiO _2. It is arranged.

Therefore, in this case as well, the diffusion of sulfur components from ZnS-SiO ₂ also causes corrosion of the pure Ag or Ag alloy reflective layer to deteriorate corrosion, causing deterioration of characteristics such as reflectance of the optical information recording medium.

As a countermeasure against the diffusion of these sulfur components, an intermediate layer mainly composed of nitride or carbide is provided between the reflective layer and the protective layer, and the recording layer and the protective layer. However, this leads to an increase in the number of stacked layers, resulting in problems such as a decrease in throughput and an increase in production cost.

In order to solve the above problems, it is urgent to find a material system having an optical property and amorphous stability equal to or higher than that of ZnS-SiO ₂ by switching to a material containing only an oxide containing no sulfide in the protective layer material. come.

As mentioned above, the oxide type protective layer material, the transparent conductive material, or the optical thin film are proposed (refer patent documents 1-3).

However, Patent Documents 1 to 3 have a problem of including a region having poor optical characteristics and amorphousness.

Patent Document 1: Japanese Patent Application Laid-Open No. 01-317167

Patent Document 2: Japanese Patent Application Laid-Open No. 2000-90745

Patent Document 3: Japanese Patent Application Laid-Open No. 2003-166052

(Initiation of invention)

The optical information recording of the present invention has stable film amorphousness, good adhesion to a recording layer, excellent mechanical properties, high transmittance, and a non-emulsification system, and therefore, optical information recording is unlikely to cause deterioration of adjacent reflective layers and recording layers. The present invention relates to a medium thin film (particularly used as a protective film), to a method of manufacturing the same, and to a sputtering target applicable to the same, thereby greatly improving the characteristics of an optical information recording medium such as repeat rewriting characteristics. It is done.

In order to solve the above problems, the present inventors conducted a intensive study and, as a result, replace the conventional protective layer material ZnS-SiO ₂ with a material containing only an oxide which does not contain an emulsion, that is, It was found that the optical properties and amorphous stability equivalent to those of ZnS-SiO ₂ can be ensured and the characteristics of the rewritable optical information recording medium can be improved.

The present invention is based on this finding,

1) A sputtering target, comprising Y ₂ O ₃ , Al ₂ O _3, and SiO ₂ .

2) Sputtering target, characterized in that consisting of Y ₂ O ₃ : 10-60 mol%, Al ₂ O ₃ : 10-40 mol% and SiO ₂ : 30-80 mol%.

3) The sputtering target according to 1 or 2 above, wherein the relative density is 95% or more.

To provide. In addition, the present invention

4) An optical information recording medium and a method of manufacturing the same, characterized in that a part of the optical information recording medium structure is formed at least as a thin film using the sputtering target according to any one of 1 to 3.

5) The sputtering target according to any one of the above 1 to 3, which forms at least part of the structure of the optical information recording medium as a thin film, and is arranged adjacent to the recording layer or the reflective layer. Information recording medium and manufacturing method thereof.

To provide.

Embodiment of the Invention

The sputtering target of the present invention is made teuneun the _{Y 2 O 3, Al 2 O} 3, SiO 2 as a material containing as a main component. SiO ₂ , a glass forming oxide, stabilizes the amorphous material. In order to obtain this effect, preferably at least the SiO ₂ 30mol%. However, when SiO ₂ is more than 80mol%, because of the optical properties (refractive index) it is to be bad, it is preferable that the upper limit is set to 80mol% in order to obtain good properties.

The addition of Al ₂ O ₃ has the effect of lowering the sintering temperature. By lowering the sintering temperature, the density can be increased and stable production is possible. In order to achieve the effect, Al ₂ O ₃ is preferably at least 10 mol%. However, large amount of addition is due to the discarding bad amorphous, and the thermal conductivity is very large, it is preferable that the Al ₂ O ₃ less than 40mol%. The cup portion Y ₂ O _3, that is, the Y ₂ O ₃ with 10-60mol%.

As a result, the relative density of the sputtering target can be made 95% or more, and a stable high density sputtering target can be manufactured.

In addition, the present invention makes it possible to form part of the optical information recording medium structure at least as a thin film by using the sputtering target described above. It is also possible to obtain an optical information recording medium and a method for manufacturing the optical information recording medium which are formed at least as part of the structure of the optical information recording medium as at least a thin film using the sputtering target of the present invention and are arranged adjacent to the recording layer or the reflective layer. .

This material is stable in optical properties and film amorphousness, and is suitable for the protective layer material of a phase change type optical recording medium. High frequency sputtering is used for film formation.

This material is suitable for a phase change recording medium having a high rewriting speed or a protective layer material for a phase change recording medium of a blue laser, because the amorphous property is stable and transmittance can be improved as described above.

Moreover, the sputtering target of this invention can make relative density into 95% or more. The improvement of the density has the effect of increasing the uniformity of the sputter film and suppressing the generation of particles during sputtering.

It is possible to provide an optical information recording medium which forms part of the optical information recording medium structure at least as a thin film by using the above-mentioned sputtering target.

It is also possible to form an optical information recording medium which is arranged adjacent to the recording layer or the reflective layer while forming part of the structure of the optical information recording medium at least as a thin film by using the sputtering target.

The thin film formed using the sputtering target of the present invention forms part of the structure of the optical information recording medium and is disposed adjacent to the recording layer or the reflective layer, but is not contaminated by S because ZnS is not used as described above. There is a remarkable effect that there is no diffusion of the sulfur component into the recording layer material sandwiched in the protective layer, and the deterioration of the recording layer is thereby eliminated.

In addition, pure Ag or Ag alloys with high reflectivity and high thermal conductivity for high capacity and high-speed recording are used as reflective layer materials, but the diffusion of sulfur components into the adjacent reflective layers is also eliminated, and the reflective layer materials are corroded in the same manner. Deterioration has an excellent effect that all causes of deterioration of characteristics such as reflectance of the optical information recording medium are eliminated.

The sputtering target of this invention can be manufactured by atmospheric pressure sintering or high temperature pressurization of the oxide powder of each element whose average particle diameter is 5 micrometers or less. As a result, a sputtering target having a relative density of 95% or more can be obtained. In this case, before sintering, it is preferable to calcinate the oxide powder containing yttrium oxide as a main component at 1000-1400 degreeC. After this calcination, the powder is ground to 3 µm or less to obtain a raw material for sintering.

In the present invention has a great feature that in particular the addition of Al ₂ O _3. As described above, we have an excellent effect that it is possible to lower the sintering temperature by the addition of Al ₂ O _3.

In the two-component system of Y ₂ O ₃ -SiO ₂ , optical properties and amorphous properties are good, but in some cases, if the temperature is not increased to a high temperature of 1700 ° C. or higher, the density cannot be sufficiently increased and stable production is difficult. There was a problem. In the present invention, a remarkable effect is obtained that the sintering temperature can be lowered to 1600 ° C. or lower, and high density and optical properties and amorphous properties can be satisfied.

In addition, by using the sputtering target of the present invention, it is possible to obtain a material with improved productivity and excellent quality, and there is a remarkable effect that an optical recording medium having an optical disk protective film can be manufactured stably at low cost.

Since the density improvement of the sputtering target of this invention can reduce an empty space and refine | miniaturize a crystal grain, and can make the sputter surface of a target uniform and smooth, the particle | grains and nozzle at the time of sputtering are reduced, and also It has a remarkable effect that the target life can also be lengthened, and the productivity can be improved due to a small quality gap.

It demonstrates based on an Example and a comparative example below. However, this embodiment is only an example to the last, and it does not restrict | limit any by this example. That is, the present invention is limited only by the claims, and includes various modifications other than the embodiments included in the present invention.

( Example 1 -4)

SiO ₂ powder, Y ₂ O ₃ powder and Al ₂ O ₃ powder of 5 µm or less in 4N equivalent were prepared, combined so as to have the composition shown in Table 1, wet-mixed and dried, and then dried at 1100 ° C. Plasticized. The calcined powder was further wetly pulverized to an average particle diameter of about 1 µm, and then a binder was added to granulate with a spray dryer. This granulated powder was press-molded by cold, and it sintered by atmospheric pressure at 1200-1600 degreeC in an oxygen atmosphere flow, and this sintered material was finished to the target shape by machining.

The sintering temperature of Example 1-4 was set to 1400 degreeC, 1550 degreeC, 1250 degreeC, and 1400 degreeC, respectively. However, if the sintering temperature was in the above range, it was possible to sinter almost equally.

Sputtering was performed using the above-mentioned 6 inch diameter size target. Sputter | spatter conditions were formed into a RF sputter | spatter, 1000 W of sputter | spatter powers, and 0.5 Pa of Ar gas pressure, and formed into a film at the target film thickness of 1500 kPa.

Transmittance (wavelength 405 nm)%, refractive index (wavelength 405 nm) of the film formation sample, and amorphous (annealing treatment (600 ° C. × 30 min, Ar atmosphere) of the film formation sample) were performed. XRD (Cu-Kα, 40 kV, 30 mA) was performed. In the measurement, the results of the measurement of the maximum peak intensity for a non-film glass substrate in the range of 2θ = 20-60 ° C.

As a result, the sputtering target of Example 1-4 reached 95 or more, and became a stable RF sputter.

The sputter film has a transmittance of 95 to 96% (405 nm), a refractive index of 1.7 to 1.9, and no specific crystal peak is seen, and it has stable amorphousness (1.0 to 1.5).

In addition, since the target of this embodiment does not use ZnS, there is no deterioration of the characteristics of the optical information recording medium due to diffusion and contamination of sulfur. Moreover, compared with the comparative example mentioned later, all of the transmittance | permeability, refractive index, and amorphous stability of the film-forming sample showed the favorable value.

(Comparative Example 1-4)

As shown in Table 1, a ZnS raw material powder was prepared in a material of a raw material powder and a composition ratio different from the conditions of the present invention, in particular, Comparative Example 4, and the sintering temperature conditions were set at 1500 to 1800 ° C. A target was produced under the same conditions as, and then a sputtered film was formed using this target. The sintering temperature of the comparative example 1-4 was 1650 degreeC, 1550 degreeC, 1750 degreeC, and 1000 degreeC (by hot press), respectively.

This result is shown in Table 1 similarly.

In the component and composition of the comparative example deviating from the composition ratio of the present invention, for example, Comparative Example 1, too much Al ₂ O ₃ was 60 mol%, resulting in poor amorphousness.

In Comparative Example 2, since Y ₂ O ₃ and Al ₂ O ₃ were few and, on the other hand, SiO ₂ was large, the balance was not balanced, and the refractive index was lower than the reference.

In Comparative Example 3, since Y ₂ O ₃ was very large and SiO ₂ was small, the balance was not balanced and the density did not sufficiently increase, resulting in poor sputtering characteristics.

Comparative Example 4 was a material having a high refractive index and a high density, but containing a large amount of ZnS and having a risk of contamination by sulfur. Moreover, the transmittance | permeability was also bad.

Since the thin film formed by using the sputtering target of the present invention forms part of the structure of the optical information recording medium and does not use ZnS, the diffusion of sulfur components into the recording layer material is eliminated, whereby There is a significant effect that the deterioration is eliminated. In addition, when pure Ag or Ag alloys having high thermal conductivity and high thermal conductivity are used as the reflective layer, the diffusion of sulfur components into the reflective layer is also eliminated, and the reflective layer deteriorates corrosion and causes property deterioration. It has an excellent effect of disappearing.

In addition to the stabilization of the amorphousness, conductivity was imparted to the target, and sintering at a relatively low temperature was possible, thus enabling stable production. As a result, a high density of 95% or more relative density can be achieved, and stable RF sputter deposition can be achieved. Thus, the remarkable effect of facilitating the controllability of the sputter and improving the sputtering efficiency has been obtained. In film formation, the particles and the nozzles generated during sputtering are reduced, It is possible to improve the mass productivity because there is little difference in quality, so that an optical recording medium having an optical disk protective film can be manufactured at low cost.

Claims (5)

A sputtering target, comprising Y ₂ O ₃ , Al ₂ O _3, and SiO ₂ . A sputtering target comprising Y ₂ O ₃ : 10-60 mol%, Al ₂ O ₃ : 10-40 mol% and SiO ₂ : 30-80 mol%. The sputtering target according to claim 1 or 2, wherein the relative density is 95% or more. An optical information recording medium and a method of manufacturing the same, wherein the sputtering target according to any one of claims 1 to 3 is used to form part of the optical information recording medium structure at least as a thin film. The sputtering target according to any one of claims 1 to 3, wherein at least a part of the structure of the optical information recording medium is formed as a thin film, and is disposed adjacent to the recording layer or the reflective layer. An optical information recording medium and a manufacturing method thereof.