KR20160061426A - Sputtering target and process for manufacturing same - Google Patents

Abstract

A basic composition in which the content of Al is 0.2 to 3.0 mol% in terms of Al ₂ O ₃ , the content of Mg and / or Si is 1 to 27 mol% in terms of MgO and / or SiO ₂ , Of a metal forming a low melting point oxide having a melting point of 1000 占 폚 or less in an amount of 0.1 to 20 wt% on an oxide weight basis. A target for forming an optical thin film having low refractive index and capable of DC sputtering because it does not contain sulfur and has a low bulk resistance, and a method for producing the same. Since the target itself is high density, there is little abnormal discharge and stable sputtering is possible. Further, the thin film formed by sputtering has a high transmittance and is constituted of a non-sulfide system, so that it is useful for forming a thin film for an optical information recording medium in which deterioration of an adjacent reflective layer and a recording layer hardly occurs. The throughput by improving the characteristics of the optical information recording medium, reducing the equipment cost, and improving the film forming speed is remarkably improved.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a sputtering target,

The present invention relates to a target for forming an optical thin film which does not contain sulfur, has a low bulk resistance and is capable of DC sputtering, has a low refractive index, and a method for producing the target.

In general, ZnS-SiO ₂ generally used for a protective layer of a phase change type optical information recording medium has excellent properties in terms of optical properties, thermal properties, adhesion to a recording layer, and the like, and is widely used. However, the rewritable optical disc represented by Blu-Ray today is strongly required to further increase the number of rewrites, increase capacity, and record at high speed.

One of the reasons for deterioration of the number of times of rewriting of the optical information recording medium or the like is diffusion of sulfur components from ZnS-SiO ₂ to the recording layer material arranged so as to be sandwiched between the protective layer ZnS-SiO ₂ . In addition, pure Ag or Ag alloy having high reflectance and high thermal conductivity is used for the reflective layer material for high-capacity and high-speed recording. Such a reflective layer is also disposed so as to contact with ZnS-SiO ₂ as a protective layer material.

Therefore, also in this case, due to the diffusion of the sulfur component from the ZnS-SiO ₂ , the pure Ag or Ag alloy reflective layer also corrodes and is deteriorated in properties such as the reflectance of the optical information recording medium.

As a countermeasure against the diffusion of these sulfur components, a structure in which an intermediate layer mainly composed of nitride or carbide is formed between the reflective layer and the protective layer, and between the recording layer and the protective layer is also carried out. However, this results in an increase in the number of stacked layers, which causes a problem that the throughput is lowered and the cost is increased. In order to solve the above problems, a material system having optical properties equal to or more than ZnS-SiO ₂ and amorphous stability has been studied by replacing the protective layer material with a material containing only a sulfide-free oxide.

In addition, since a ceramic target such as ZnS-SiO ₂ has a high bulk resistance value, it can not be formed by a DC sputtering apparatus, and a high-frequency sputtering (RF) apparatus is usually used.

However, this high-frequency sputtering (RF) device has many drawbacks such that the apparatus itself is expensive, the sputtering efficiency is poor, the power consumption is large, the control is complicated, and the deposition rate is low. In addition, in order to increase the deposition rate, when the high power is applied, there is a problem that the substrate temperature rises and deformation of the polycarbonate substrate occurs. In addition, since ZnS-SiO ₂ has a thick film thickness, throughput reduction and cost increase have been a problem.

In view of the above, there has been proposed a sintered target target in which an element having a positive valence of 3 or more is added singly to ZnO as a DC sputterable target (for example, refer to Patent Document 1). However, in this case, it is considered that the low bulk resistance value and the low refractive index can not be satisfied at the same time.

Also, as a transparent conductive film and a sintered body for manufacturing the transparent conductive film, a manufacturing method by a high-frequency or direct current magnetron sputtering method in which Group II, Group III or Group IV elements are variously combined has been proposed (see Patent Document 2). However, it is considered that the object of this technique is not to reduce the resistance of the target, and it can not sufficiently make the low bulk resistance value compatible with the low refractive index.

A ZnO sputtering target under the condition that at least one of the elements to be added is dissolved in ZnO has been proposed (see Patent Document 3). This is a problem because there is a limitation in the composition of the components, and therefore there is a limitation in the optical characteristics, because the addition of the elements is a condition.

From the above, the present applicant has been able to solve the above problems at once by carrying out the invention described in Patent Document 4 below. That is, by providing a sputtering target having a low refractive index and a low bulk resistance made of Al ₂ O ₃ : 0.2 to 3.0 at%, MgO and / or SiO ₂ : 1 to 27 at%, and the remainder ZnO, The characteristics could be greatly improved. However, one problem has arisen here.

For the target, high density is required to perform stable sputtering. However, in the above-mentioned component system, it was difficult to increase the sintering temperature due to decomposition (evaporation) of ZnO when the sintering temperature was raised for high density. Therefore, low temperature sintering and high density were required.

Japanese Patent Application Laid-Open No. 2-149459 Japanese Patent Application Laid-Open No. 8-264022 Japanese Laid-Open Patent Publication No. 11-322332 Japanese Patent Publication No. 4828529

The present invention relates to a target for forming an optical thin film having a low refractive index and capable of performing DC sputtering by proper selection of a material, which maintains the characteristics of Patent Document 4, that is, does not contain sulfur and has a low bulk resistance, And to provide a high density sputtering target. In addition, a thin film for an optical information recording medium (particularly, a protective film for use as a protective film, which is excellent in adhesion to a recording layer, mechanical properties, high transmittance, ) And a method of manufacturing the sputtering target. Thus, the object of the present invention is to significantly improve the throughput by improving the characteristics of the optical information recording medium, reducing the equipment cost, and improving the film forming speed.

In order to solve the above problems, the inventors of the present invention have conducted intensive studies, and as a result, it has been found that high density can be achieved by adding a metal forming a low melting point oxide to the above Patent Document 4. In addition, it is possible to secure optical characteristics and amorphous stability equivalent to those of ZnS-SiO _2, and to perform high-speed film formation by DC (direct current) sputtering, and to perform RF sputtering if necessary, , And the productivity was improved.

The present invention, based on this finding,

1) A metal containing a metal forming a low melting point oxide with respect to a basic composition composed of three elements or four elements of zinc (Zn), aluminum (Al), magnesium (Mg) and / or silicon (Si) , The content of Al is 0.2 to 3.0 mol% in terms of Al ₂ O ₃ , the content of Mg and / or Si is 1 to 27 mol% in terms of MgO and / or SiO ₂ , the content of Zn in terms of ZnO , And further contains 0.1 to 20 wt% of a metal forming a low melting point oxide having a melting point of 1000 DEG C or lower, in terms of oxides, based on the basic composition of the sputtering target,

2) The sputtering target according to 1) above, wherein the content of the metal forming the low melting point oxide is 0.1 to 10 wt% in terms of oxide,

3) A low melting point oxide selected from B ₂ O ₃ , P ₂ O ₅ , K ₂ O, V ₂ O ₅ , Sb ₂ O ₃ , TeO ₂ , Ti ₂ O ₃ , PbO, Bi ₂ O ₃ and MoO ₃ The sputtering target according to 1) or 2) above, wherein the sputtering target is at least one material,

4) The sputtering target according to any one of 1) to 3) above, wherein the content of Mg and / or Si is 10 to 27 mol% in terms of MgO and / or SiO ₂ ,

5) The sputtering target according to any one of 1) to 4) above, wherein the relative density is 98% or more,

6) The sputtering target according to any one of 1) to 5) above, wherein the target has a bulk resistance of 10 Ω · cm or less,

7) The optical recording medium according to any one of 1) to 6) above, which is used for an optical thin film for forming a protective layer, a reflective layer or a semi-transparent layer of an optical information recording medium, an organic EL TV, A sputtering target according to any one of claims 1 to 3,

8) A raw material powder for basic sintering is prepared so that the Al ₂ O ₃ powder is 0.2 to 3.0 ㏖%, the MgO and / or SiO ₂ powder is 1 to 27 ㏖% and the remainder is ZnO powder and the total amount thereof is 100 ㏖% And further adding 0.1 to 20 wt% of a low melting point oxide powder having a melting point of 1000 DEG C or lower to prepare a raw material for sinter and subjecting the raw material for sinter to hot pressing at a temperature higher than 800 DEG C and lower than 1150 DEG C Manufacturing method,

9) The method for producing a sputtering target according to 8) above, wherein the relative density is 98% or more,

10) A method for producing a sputtering target according to any one of the above 8) to 9), wherein the bulk resistance is made 10 Ω · cm or less,

Or more of the sputtering target can easily obtain a target having a relative density of 98% or more and a bulk resistance of 10 Ω · cm or less. It is useful as a target for forming a thin film for use in an optical thin film for forming a protective layer, a reflective layer or a semi-transparent layer of an optical information recording medium, an organic EL TV, an electrode for a touch panel, or a sheet layer of a hard disk .

The present invention further provides the following thin film formed by using the target.

11) A metal containing a metal forming a low melting point oxide with respect to a basic composition composed of three elements or four elements of zinc (Zn), aluminum (Al), magnesium (Mg) and / or silicon (Si) , The content of Al is 0.2 to 3.0 mol% in terms of Al ₂ O ₃ , the content of Mg and / or Si is 1 to 27 mol% in terms of MgO and / or SiO _2, and the content of Zn in terms of ZnO , And further contains 0.1 to 20 wt% of a metal forming a low melting point oxide having a melting point of 1000 占 폚 or less on an oxide weight basis,

12) The thin film according to the above 11), wherein the content of the metal forming the low melting point oxide is 0.1 to 10 wt% in terms of oxide,

13) The method according to claim ₁ , wherein the low melting point oxide is selected from B ₂ O ₃ , P ₂ O ₅ , K ₂ O, V ₂ O ₅ , Sb ₂ O ₃ , TeO ₂ , Ti ₂ O ₃ , PbO, Bi ₂ O ₃ , MoO ₃ A thin film according to the above 11) or 12)

14) The thin film according to any one of the above 11) to 13), wherein the content of Mg and / or Si is 10 to 27 mol% in terms of MgO and / or SiO ₂ ,

(15) The thin film according to any one of (11) to (14) above, wherein the refractive index (wavelength 550 nm)

(16) The thin film according to any one of (11) to (15) above, wherein an extinction coefficient (? = 450 nm)

17) The optical information recording medium as described in 11) to 16) above, which is used for an optical thin film forming a protective layer, a reflective layer or a semi-transparent layer of an optical information recording medium, an organic EL TV, ). ≪ / RTI >

By the above, protection cheungjae a ZnS-SiO _2, by replacing the material of the oxide but not containing a sulfide, with the inhibited deterioration due to sulfur of such adjacent reflective layer and recording layer, ZnS-SiO ₂ is equal to or It is possible to achieve high-speed film formation by reducing the bulk resistance value. In addition, since a high-density sputtering target can be provided, the occurrence of abnormal discharge can be reduced, and stable sputtering can be achieved. Also, it is possible to provide a sputtering target useful for a thin film for an optical information recording medium (particularly, a protective film, a reflective layer, and a semi-permeable film layer) having excellent properties such as adhesion to a recording layer, excellent mechanical properties and high transmittance. As described above, it has an excellent effect that it is possible to remarkably improve the throughput by improving the characteristics of the optical information recording medium, reducing the equipment cost, and improving the film forming speed.

FIG. 1 is a graph showing vapor pressure curves of Al ₂ O ₃ , MgO, SiO ₂ and ZnO.
2 is a diagram showing the results of thermodynamic simulation of the behavior of ZnO in the production of a hot press (HP).
Fig. 3 is a graph showing reduction in shrinkage temperature as compared with no addition when 0.5 wt% and 1.0 wt% of B ₂ O ₃ is added as a low melting point oxide.

The sputtering target of the present invention is characterized in that a sputtering target of the present invention has a low melting point oxide with respect to a basic composition composed of three elements or four elements of zinc (Zn), aluminum (Al), magnesium (Mg) and / or silicon (Si) Wherein the content of Al is 0.2 to 3.0 mol% in terms of Al ₂ O ₃ , the content of Mg and / or Si is 1 to 27 mol% in terms of MgO and / or SiO _{2, and the} remainder is Zn Wherein the metal has a melting point of not higher than 1000 占 폚 and contains a metal forming a low melting point oxide in an amount of 0.1 to 20 wt% based on the weight of the oxide. And has a refractive index.

That is, at least one kind of Al ₂ O ₃ that gives conductivity to ZnO and MgO and SiO ₂ that adjusts the refractive index, and a low melting point oxide having a melting point of 1000 ° C. or lower are dispersed in ZnO.

Further, in the present invention, the content of the metal in the sintered body is defined in terms of each oxide, and a part or all of the metals in the sintered body exists as a composite oxide. In the component analysis of the sintered body which is usually used, the content of each component is measured not as an oxide but as a metal.

For the ZnO-Al ₂ O ₃ -MgO-SiO ₂ target (ZnO main component) described in Patent Document 4, it is necessary to increase the density to perform stable sputtering. As a high density method, it is conceivable to increase the sintering temperature. In this system, since the vapor pressure of ZnO is high (see FIG. 1), it is difficult to increase the density by decomposition (evaporation) of ZnO.

In the hot press production, there is a problem that ZnO is reduced by contact with carbon under high temperature, and the die is eroded.

As for the result of the thermodynamic simulation of the ZnO behavior (see Fig. 2) for the production by the hot press (HP), since reduction of ZnO occurs at 1100 ° C even under pressure under the condition of coexistence of carbon, It needs to be lower than 1100 占 폚.

As a method of low-temperature sintering and densification, the addition of a low-melting-point oxide was studied and the sintering temperature was set to be lower than 1100 ° C. As a result, it was found that addition of an oxide having a melting point of 1000 DEG C or lower was effective.

As the low melting point oxides, in particular, oxides selected from B ₂ O ₃ , P ₂ O ₅ , K ₂ O, V ₂ O ₅ , Sb ₂ O ₃ , TeO ₂ , Ti ₂ O ₃ , PbO, Bi ₂ O ₃ and MoO ₃ Addition of the material is effective.

Table 1 shows the melting points of these low melting point oxides. Of these, B ₂ O ₃ is particularly effective for handling because it is not toxic. This makes it possible to increase the densification of the target, eliminate the abnormal discharge, and enable stable sputtering.

By adding the metal forming the low melting point oxide in an amount of 0.1 wt% or more and 20.0 wt% or less in terms of the weight of the oxide, the sintering temperature can be effectively lowered. The sintering temperature can be lowered to not more than 0.1 wt% and not more than 10.0 wt%, preferably not less than 0.1 wt% and not more than 5.0 wt%, without significantly deteriorating the characteristics of the base material. The sintering temperature can be lowered without changing the characteristics of the base material.

* The functions and effects of other component compositions (materials) are the same as those of Patent Document 4, but they are described again. That is, when the content of Al ₂ O ₃ is less than 0.2 mol%, the bulk resistance value increases and the object of the present invention can not be achieved. When Al ₂ O ₃ exceeds 3.0 mol%, the bulk resistance is increased and the DC sputtering becomes impossible, which is not preferable.

MgO and SiO ₂ can be added singly or in combination, and the object of the present invention can be achieved. If the content of MgO and / or SiO ₂ is less than 1 mol%, the reduction of the refractive index can not be attained. If the content of MgO and / or SiO ₂ exceeds 27 mol%, the bulk resistance value increases and the film formation rate decreases remarkably. Therefore, it is preferable to set the composition range of the above components.

Further, MgO and / or SiO ₂ is more preferably 10 to 27 mol%. The reason for this is that the addition of about 10 to 27 mol%, as compared with the case where MgO and / or SiO ₂ is 1 to 10 mol%, can further improve the transmittance and reduce the refractive index.

The sputtering target of the present invention is useful for industrially producing an optical thin film for an optical disk having a refractive index of 2.00 or less (550 nm). In particular, it can be used as a target for forming a protective layer, a reflective layer, or a semi-transparent layer of an optical information recording medium.

With the increase in capacity of optical information recording media, multi-layer recording has become available for recordable / rewritable DVDs. In the case of adopting such a multilayer structure, it is necessary that the first-layer reflection layer located between the first layer and the second layer has transmittance in order to irradiate write / read output light for the second layer. When an Ag alloy is used as the semi-transparent layer, there arises a problem of sulfuration due to reaction with ZnS-SiO ₂ used as a protective layer.

As such a semitransparent layer free from the problem of sulfuration, a high-refractive index layer and a low-refractive index layer may be alternately laminated to provide a semi-transmissive layer having arbitrary optical characteristics. The target of the present invention can be preferably used as a low refractive index layer constituting a transflective layer in addition to the protective layer. Then, the bulk resistance of the target can be 10 Ω · cm or less. By reducing the bulk resistance value, high-speed film formation by DC sputtering becomes possible. Depending on the choice of material, RF sputtering is required, but in that case there is an improvement in the deposition rate. As a result, the sputtering film formation rate, optical characteristics (refractive index, transmittance) become optimum ranges. The range deviating from the numerical value range tends to deteriorate the above characteristics.

When attempting to form a low refractive index film for optical adjustment, most of the low refractive index material has no conductivity, so DC sputtering can not be performed and there is a problem that the film forming rate is slow. On the other hand, in general conductive transparent film materials such as ITO and AZO, although DC sputtering is possible, the refractive index is as high as 2.0 or more. Therefore, the present invention can be said to be one of the features that has a refractive index of 2.0 or less and can perform DC sputtering.

Since the volume resistivity of the sputtering target needs to be DC sputtering, the upper limit of the DC sputtering possible is 10 Ω cm, but there is no particular problem at a low degree. In addition, the volume resistivity of the thin film formed by sputtering using this target is in the range of 1 x 10 < ³ > to 1 x 10 < ⁹ >

The extinction coefficient (? = 450 nm) of the film obtained by sputtering the sputtering target of the present invention is preferably less than 0.01 although it may vary depending on the film structure and the film thickness at the time of use. When a transparent film is required, zero is ideal. The present invention particularly targets short wavelength side even in the visible light region. The oxide film generally has difficulty in suppressing the absorption on the short wavelength side of the visible light region, has absorption on the short wavelength side, and tends to become a yellowish film (for example, IZO is a yellowish film).

In the production of the sputtering target of the present invention, 0.2 to 3.0 mol% of Al ₂ O ₃ powder, 1 to 27 mol% of MgO and / or SiO ₂ powder, and the remainder of ZnO powder are used as raw materials, , And 0.1 to 20 wt% of a low melting point oxide powder having a melting point of 1000 DEG C or lower is further added to the raw material powder to obtain a sintering raw material. Next, the mixed powder is hot-pressed at a temperature higher than 800 ° C and lower than 1150 ° C.

Thereby, the base composition (composition of 100 mol%) composed of 0.2 to 3.0 mol% of Al ₂ O ₃ , 1 to 27 mol% of MgO and / or SiO ₂ , and the remainder of ZnO, A sputtering target containing 0.1 to 20 wt% of a metal forming a melting point oxide in terms of oxides can be obtained.

By this sintering, the relative density can be set to 98% or more, and the bulk resistance of the target can be made 10 Ω · cm or less.

Further, Al ₂ O ₃ powder and ZnO powder to be raw materials are preliminarily mixed and preliminarily fired in advance, and then MgO and / or SiO ₂ powder is added to the temporarily sintered Al ₂ O ₃ -ZnO powder (AZO powder) The powder of the low melting point oxide may be mixed and sintered.

In the case of simply adding MgO and / or SiO ₂ powder, Al ₂ O ₃ reacts with MgO and / or SiO ₂ to become spinel, and the bulk resistance value tends to rise. Therefore, in order to achieve lower bulk resistance of the sintered body, sintering is preferably performed using temporarily sintered Al ₂ O ₃ -ZnO powder (AZO powder).

Al ₂ O ₃ powder and ZnO powder to be raw materials were previously mixed and preliminarily calcined to form AZO powder and MgO powder and SiO ₂ powder to be raw materials were mixed in the same manner and temporarily calcined. It is recommended that the sintered Al ₂ O ₃ -ZnO powder (AZO powder) is mixed with the MgO-SiO ₂ temporary calcined powder and the low melting point oxide powder and sintered. As a result, the spinelization can be further suppressed and a low bulk resistance can be achieved.

In addition, since the sputtering target of the present invention can have a relative density of 98% or more as described above, it has an excellent effect of increasing the uniformity of the sputtering film and suppressing the generation of particles during sputtering.

It is possible to provide an optical information recording medium in which a part of the optical information recording medium structure is formed as at least a thin film using the above-described sputtering target. Further, by using the sputtering target, it is possible to manufacture an optical information recording medium in which a part of the structure of the optical information recording medium is formed at least as a thin film, and the recording layer or the reflection layer is disposed adjacent to the sputtering target.

The present invention makes it possible to form a thin film by DC sputtering (direct current sputtering) by making it a target having zinc oxide as a main component in this way. DC sputtering is superior to RF sputtering in that the deposition rate is high and the sputtering efficiency is good, and the throughput can be remarkably improved.

In addition, the DC sputtering apparatus is advantageous in that it is inexpensive, easy to control, and consumes a small amount of electric power. The film thickness of the protective film itself can be made thinner, so that the productivity and the substrate heating prevention effect can be further exerted. Further, in the present invention, depending on the manufacturing conditions and the selection of materials, it may be necessary to perform RF sputtering. In this case, however, the film forming speed may be improved.

The thin film formed by using the sputtering target of the present invention forms a part of the structure of the optical information recording medium and is disposed adjacent to the recording layer or the reflection layer. Since ZnS is not used as described above, There is no contamination by the protective layer and there is no diffusion of the sulfur component into the recording layer material arranged so as to be sandwiched between the protective layers and there is a remarkable effect that the deterioration of the recording layer by this is eliminated.

In addition, although pure Ag or Ag alloy having high reflectance and high thermal conductivity is used for the reflective layer material for large capacity and high speed recording, the diffusion of the sulfur component into the adjacent reflective layer also disappears, and similarly, And the cause of deterioration of characteristics such as the reflectance of the optical information recording medium is eliminated.

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

The density improvement of the sputtering target of the present invention can reduce the number of particles and nodules at the time of sputtering because the density of the sputtering target can be reduced by finely reducing the vacancies and the sputter surface of the target can be made even and smooth, Can be made longer, and it is possible to improve the mass productivity with less variation in quality.

Example

The following is a description based on examples and comparative examples. Note that this embodiment is merely an example and is not limited at all 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)

ZnO powder corresponding to 4 N, MgO powder having an average particle diameter of 5 탆 or less corresponding to 4 N, Al ₂ O ₃ powder having an average particle diameter of 5 탆 or less corresponding to 4 N, SiO ₂ powder and B ₂ O ₃ powder having an average particle diameter of 5 μm or less corresponding to 4 N were prepared. Next, these powders were combined at the blending ratios shown in Table 2, mixed, and hot-pressed (HP) at a temperature of 1050 캜. The pressure of the hot press was 220 kg / cm 2.

As shown in Table 2, the ratios of the raw materials were 72.0 mol% of ZnO powder, 24.6 mol% of MgO powder, 1.2 mol% of Al ₂ O ₃ powder and 2.2 mol% of SiO ₂ powder, %, Respectively. Further, 1.0 wt% of B ₂ O ₃ powder was further blended to obtain a raw material for sintering. After sintering, the sintered body was finished into a target shape by machining. The density of the target of the sintered body reached 99.6%, and the bulk resistance was 3.5 × 10 ^-3 Ω · cm (3.5 mΩ · cm).

In addition, the density shown in this specification means the relative density. Each relative density is obtained by measuring the density of the target, that is, the composite oxide produced, with respect to the theoretical density of the target calculated from the density of the raw material, and obtaining the relative density from each density. As shown in Table 2, there is an example in which the relative density exceeds 100% because it is not a simple mixture of raw materials.

Sputtering was carried out using the target of 6 inches in size finishing the above. The sputtering conditions were DC sputtering, sputtering power of 500 W, Ar-2% O ₂ mixed gas pressure of 0.5 Pa, and a film thickness of 1500 Å. The deposition rate was 2.8 Å / sec, stable DC sputtering was possible, and good sputtering was achieved. The film-forming sample had a refractive index (wavelength: 550 nm) of 1.943, a volume resistivity of 2 × 10 ⁵ Ω · cm and an extinction coefficient (λ = 450 nm): <0.01. These conditions and results are summarized in Table 2.

(Comparative Example 1)

ZnO powder corresponding to 4 N, MgO powder having an average particle diameter of 5 탆 or less corresponding to 4 N, Al ₂ O ₃ powder having an average particle diameter of 5 탆 or less corresponding to 4 N, SiO ₂ powder was prepared. Next, these powders were combined at the blending ratios shown in Table 2, mixed and hot-pressed (HP) at a temperature of 1150 캜. The pressure of the hot press was 220 kg / cm 2.

As shown in Table 2, the ratios of the raw materials were ZnO powder: 72.0 mol%, MgO powder: 24.6 mol%, Al ₂ O ₃ powder: 1.2 mol%, and SiO ₂ powder: 2.2 mol%. After sintering, the sintered body was finished into a target shape by machining. The density of the sintered body target was 97.6%, which was lower than that of Example 1. The bulk resistance was 2.0 × 10 ^-3 Ω · cm.

Sputtering was carried out using the target of 6 inches in size finishing the above. The sputtering conditions were DC sputtering, sputtering power of 500 W, Ar-2% O ₂ mixed gas pressure of 0.5 Pa, and a film thickness of 1500 Å. The deposition rate was 2.2 angstroms / sec. However, there was an abnormal discharge and generation of particles during sputtering, and stable DC sputtering could not be performed. The film-forming sample had a refractive index (wavelength: 550 nm) of 1.948, a volume resistivity of 1 × 10 ⁵ Ω · cm, and an extinction coefficient (λ = 450 nm): <0.01. These conditions and results are summarized in Table 2.

(Comparative Example 2)

ZnO powder corresponding to 4 N, MgO powder having an average particle diameter of 5 탆 or less corresponding to 4 N, Al ₂ O ₃ powder having an average particle diameter of 5 탆 or less corresponding to 4 N, SiO ₂ powder was prepared. Next, these powders were combined at the blending ratios shown in Table 2, mixed and hot-pressed (HP) at a temperature of 1050 占 폚 (lower than Comparative Example 1). The pressure of the hot press was 220 kg / cm 2.

As shown in Table 2, the ratios of the raw materials were 72.0 mol% of ZnO powder, 24.6 mol% of MgO powder, 1.2 mol% of Al ₂ O ₃ powder and 2.2 mol% of SiO ₂ powder, Likewise. After sintering, the sintered body was finished into a target shape by machining. The density of the target of the sintered body was 90.9%, which was lower than that of Example 1 and lower than that of Comparative Example 1. The bulk resistance was 3.0 × 10 ^-3 Ω · cm.

Using the finishing finished target of 6 inches in size, DC sputtering was performed under the same conditions as in Comparative Example 1, but the DC sputtering was stopped because the stable DC sputtering could not be performed. These conditions and results are summarized in Table 2.

(Example 2)

ZnO powder corresponding to 4 N, MgO powder having an average particle diameter of 5 탆 or less corresponding to 4 N, Al ₂ O ₃ powder having an average particle diameter of 5 탆 or less corresponding to 4 N, SiO ₂ powder and B ₂ O ₃ powder having an average particle diameter of 5 μm or less corresponding to 4 N were prepared.

Next, these powders were combined at the blending ratios shown in Table 2, mixed and hot-pressed (HP) at a temperature of 1050 캜. The pressure of the hot press was 220 kg / cm 2.

As shown in Table 2, the compounding ratio of the raw materials was 72.0 mol% of ZnO powder, 24.6 mol% of MgO powder, 1.2 mol% of Al ₂ O ₃ powder and 2.2 mol% of SiO ₂ powder, %, Respectively. Further, B ₂ O ₃ powder: 0.5 wt% was further blended to obtain a raw material for sintering.

The blending ratio of B ₂ O ₃ powder was lower than that of Example 1. After sintering, the sintered body was finished into a target shape by machining. The density of the target of the sintered body reached 99.5%, and the bulk resistance was 2.9 × 10 ^-3 Ω · cm (2.9 mΩ · cm). The density was slightly lower than that of Example 1.

Sputtering was carried out using the target of 6 inches in size finishing the above. The sputtering conditions were DC sputtering, sputtering power of 500 W, Ar-2% O ₂ mixed gas pressure of 0.5 Pa, and a film thickness of 1500 Å. The deposition rate was 2.6 A / sec, stable DC sputtering was performed, and good sputtering was achieved. The film formation sample had a refractive index (wavelength: 550 nm) of 1.945, a volume resistivity of 2 × 10 ⁵ Ω · cm, and an extinction coefficient (λ = 450 nm): <0.01. These conditions and results are summarized in Table 2.

(Example 3)

ZnO powder corresponding to 4 N, MgO powder having an average particle diameter of 5 탆 or less corresponding to 4 N, Al ₂ O ₃ powder having an average particle diameter of 5 탆 or less corresponding to 4 N, SiO ₂ powder and B ₂ O ₃ powder having an average particle diameter of 5 μm or less corresponding to 4 N were prepared.

Next, these powders were combined at the blending ratios shown in Table 2, mixed and hot-pressed (HP) at a temperature of 1050 캜. The pressure of the hot press was 220 kg / cm 2.

As shown in Table 2, the blending ratio of the raw materials was 89.3 mol% of ZnO powder, 9.2 mol% of MgO powder, 0.7 mol% of Al ₂ O ₃ powder and 0.8 mol% of SiO ₂ powder, %, Respectively. Further, 1.0 wt% of B ₂ O ₃ powder was further blended to obtain a raw material for sintering. B ₂ O ₃ powder was the same as that in Example 1.

And the mixing ratio of the other raw materials was changed. After sintering, the sintered body was finished into a target shape by machining. The density of the target of the sintered body reached 101.6%, and the bulk resistance was 2.2 x 10 ^-3 ? 占 (m (2.2 m? 占) m). The density was further improved as compared with Example 1.

Sputtering was carried out using the target of 6 inches in size finishing the above. The sputtering conditions were DC sputtering, sputtering power of 500 W, Ar-2% O ₂ mixed gas pressure of 0.5 Pa, and a film thickness of 1500 Å. The deposition rate was 3.0 Å / sec, stable DC sputtering was possible, and good sputtering was obtained. The film-forming sample had a refractive index (wavelength: 550 nm) of 1.973, a volume resistivity of 3 × 10 ³ Ω · cm, and an extinction coefficient (λ = 450 nm): <0.01. These conditions and results are summarized in Table 2.

(Example 4)

ZnO powder corresponding to 4 N, MgO powder having an average particle diameter of 5 탆 or less corresponding to 4 N, Al ₂ O ₃ powder having an average particle diameter of 5 탆 or less corresponding to 4 N, SiO ₂ powder and B ₂ O ₃ powder having an average particle diameter of 5 μm or less corresponding to 4 N were prepared. Next, these powders were combined at the blending ratios shown in Table 2, mixed and hot-pressed (HP) at a temperature of 1050 캜. The pressure of the hot press was 220 kg / cm 2.

As shown in Table 2, the blending ratio of the raw materials was 68.9 mol% of ZnO powder, 24.6 mol% of MgO powder, 1.1 mol% of Al ₂ O ₃ powder and 5.4 mol% of SiO ₂ powder in total of 100 mol% As a basic raw material. Further, 1.0 wt% of B ₂ O ₃ powder was further blended to obtain a raw material for sintering. B ₂ O ₃ powder was the same as that in Example 1.

And the mixing ratio of the other raw materials was changed. After sintering, the sintered body was finished into a target shape by machining. The density of the target of the sintered body reached 101.6%, and the bulk resistance was 3.3 x ^10-3 ? 占 (m (3.3 m? 占) m). The density was further improved than in Examples 1 and 2.

Sputtering was carried out using the target of 6 inches in size finishing the above. The sputtering conditions were DC sputtering, sputtering power of 500 W, Ar-2% O ₂ mixed gas pressure of 0.5 Pa, and a film thickness of 1500 Å. The deposition rate was 2.9 Å / sec, stable DC sputtering was performed, and good sputtering was achieved. The film-forming sample had a refractive index (wavelength: 550 nm) of 1.899, a volume resistivity of 1 x 10 ⁶ ? 占 ㎝ m and an extinction coefficient (? = 450 nm): <0.01. These conditions and results are summarized in Table 2.

(Example 5)

ZnO powder corresponding to 4 N, MgO powder having an average particle diameter of 5 탆 or less corresponding to 4 N, Al ₂ O ₃ powder having an average particle diameter of 5 탆 or less corresponding to 4 N, SiO ₂ powder and Bi ₂ O ₃ powder having an average particle size of 5 μm or less corresponding to 4 N were prepared.

Next, these powders were combined at the blending ratios shown in Table 2, mixed and hot-pressed (HP) at a temperature of 1050 캜. The pressure of the hot press was 220 kg / cm 2.

As shown in Table 2, the compounding ratio of the raw materials was 72.0 mol% of ZnO powder, 24.6 mol% of MgO powder, 1.2 mol% of Al ₂ O ₃ powder and 2.2 mol% of SiO ₂ powder, %, Respectively. Further, Bi ₂ O ₃ powder: 1.0 mol% was further blended to obtain a sintering raw material. The mixing ratio of the Bi ₂ O ₃ powder was set to be equal to that of Example 1. The difference from Example 1 is that Bi ₂ O ₃ powder was used instead of B ₂ O ₃ powder.

After sintering, the sintered body was finished into a target shape by machining. The density of the target of the sintered body was 98.5%, and the bulk resistance was 2.3 × 10 ^-3 Ω · cm (2.3 mΩ · cm).

Sputtering was carried out using the target of 6 inches in size finishing the above. The sputtering conditions were DC sputtering, sputtering power of 500 W, Ar-2% O ₂ mixed gas pressure of 0.5 Pa, and a film thickness of 1500 Å. The deposition rate was 2.8 Å / sec, stable DC sputtering was possible, and good sputtering was achieved. The film-forming sample had a refractive index (wavelength: 550 nm) of 1.953, a volume resistivity of 5 × 10 ⁵ Ω · cm and an extinction coefficient (λ = 450 nm): <0.01. These conditions and results are summarized in Table 2.

(Example 6)

ZnO powder corresponding to 4 N, ZnO powder corresponding to 4 N, Al ₂ O ₃ powder having an average particle diameter of 5 탆 or less, SiO ₂ powder having an average particle diameter of 5 탆 or less corresponding to 4 N, Of B ₂ O ₃ powder was prepared. Next, these powders were combined at the blending ratios shown in Table 2, mixed and hot-pressed (HP) at a temperature of 1050 캜. The pressure of the hot press was 220 kg / cm 2.

As shown in Table 2, the ratios of the raw materials were 80.5 mol% of ZnO powder, 2.5 mol% of Al ₂ O ₃ powder and 17.0 mol% of SiO ₂ powder, and the total amount was 100 mol% . Then, B ₂ O ₃ powder: 1.5 wt% was further added as an additive to prepare a sintering raw material. After sintering, the sintered body was finished into a target shape by machining. The density of the target of the sintered body reached 99.6%, and the bulk resistance was 1.3 × 10 ^-3 Ω · cm (1.3 mΩ · cm).

Sputtering was carried out using the target of 6 inches in size finishing the above. The sputtering conditions were DC sputtering, sputtering power of 500 W, Ar-2% O ₂ mixed gas pressure of 0.5 Pa, and a film thickness of 1500 Å. The deposition rate was 2.4 A / sec, stable DC sputtering was possible, and good sputtering was achieved. The film-forming sample had a refractive index (wavelength: 550 nm) of 1.84, a volume resistivity of 6 × 10 ⁴ Ω · cm, and an extinction coefficient (λ = 450 nm): <0.01. These conditions and results are summarized in Table 2.

(Example 7)

ZnO powder corresponding to 4 N, MgO powder having an average particle diameter of 5 탆 or less corresponding to 4 N, Al ₂ O ₃ powder having an average particle diameter of 5 탆 or less corresponding to 4 N, B ₂ O ₃ powder was prepared. Next, these powders were combined at the blending ratios shown in Table 2, mixed and hot-pressed (HP) at a temperature of 1050 캜. The pressure of the hot press was 220 kg / cm 2.

As shown in Table 2, the ratios of the raw materials were 79.9 mol% of ZnO powder, 17.6 mol% of MgO powder and 2.5 mol% of Al ₂ O ₃ powder, and the total amount was 100 mol%, thereby obtaining a basic raw material. Further, B ₂ O ₃ powder: 1.5 wt% was further blended to obtain a sintering raw material. After sintering, the sintered body was finished into a target shape by machining. The density of the target of the sintered body reached 99.4%, and the bulk resistance was 2.1 × 10 ^-3 Ω · cm (2.1 mΩ · cm).

Sputtering was carried out using the target of 6 inches in size finishing the above. The sputtering conditions were DC sputtering, sputtering power of 500 W, Ar-2% O ₂ mixed gas pressure of 0.5 Pa, and a film thickness of 1500 Å. The deposition rate was 2.6 A / sec, stable DC sputtering was performed, and good sputtering was achieved. The film-forming sample had a refractive index (wavelength: 550 nm) of 1.95, a volume resistivity of 7 × 10 ⁴ Ω · cm, and an extinction coefficient (λ = 450 nm): <0.01. These conditions and results are summarized in Table 2.

(Comparative Example 3)

ZnO powder corresponding to 4 N, MgO powder having an average particle diameter of 5 탆 or less corresponding to 4 N, Al ₂ O ₃ powder having an average particle diameter of 5 탆 or less corresponding to 4 N, SiO ₂ powder and B ₂ O ₃ powder having an average particle diameter of 5 μm or less corresponding to 4 N were prepared. Next, these powders were combined at the mixing ratios shown in Table 2, mixed and hot-pressed (HP) at a temperature of 1000 占 폚. The pressure of the hot press was 220 kg / cm 2.

As shown in Table 2, the ratios of the raw materials were 72.0 mol% of ZnO powder, 24.6 mol% of MgO powder, 1.2 mol% of Al ₂ O ₃ powder and 2.2 mol% of SiO ₂ powder, %, Respectively. Further, B ₂ O ₃ powder: 0.5 wt% was further blended to obtain a raw material for sintering. After sintering, the sintered body was finished into a target shape by machining. The density of the target of the sintered body reached 99.6% and the bulk resistance was 3.2 x 10 ^-3 ? 占 (m (3.2 m? 占) m).

Using the finishing finished target of 6 inches in size, DC sputtering was performed under the same conditions as in Comparative Example 1, but the DC sputtering was stopped because the stable DC sputtering could not be performed. These conditions and results are summarized in Table 2.

(Summary of comprehensive evaluation according to the embodiment and the comparative example)

As is clear from the above Comparative Example 1, the density was as low as 97.6% in the hot press at 1150 DEG C and 220 kg / cm &lt; 2 &gt; without the addition of the low melting point oxide. Even at this temperature, reduction of ZnO is taking place, indicating that low-temperature sintering is necessary.

As shown in Comparative Example 2, when HP was performed at 1050 占 폚 and 220 kg / cm2 in the raw material, the density was further lowered to 90.9%.

As shown in the above example, when B ₂ O ₃ was added as the low melting point oxide, the shrinkage temperature was lowered in the addition of 0.5 wt% and 1.0 wt% (see FIG. 3).

As shown in Examples 1 and ₂ , the densities were 99.6% and 99.5% for B ₂ O ₃ additions of 0.5 and 1.0 wt%, respectively, and densification in low temperature sintering was achieved. The bulk resistance value was 2.0 mΩ · cm to 4.0 mΩ · cm, which was 10 mΩ · cm or less, and DC sputtering was possible.

As a further lowering temperature, as shown in Comparative Example 3, H / P was carried out at 1000 占 폚 for 0.5 wt% of B ₂ O ₃ addition, and as a result, the density became 93.4%, and high density was not achieved. Also, as shown in Examples 3 and 4, it was confirmed that the addition of B ₂ O ₃ enables low-temperature sintering and high densification of the case of changing the composition of ZnO-Al ₂ O ₃ -MgO-SiO ₂ . It was possible to obtain a problematic bulk resistance value in both DC sputtering.

As shown in inde evaluation results for the case of not adding to the case where with respect to the addition of B ₂ O ₃ as a low-melting-point oxide, even when using a Bi ₂ O ₃ as a low-melting-point oxide, Example 5, B ₂ The same effect as that of the addition of O ₃ was obtained.

Although not shown in the examples, even when the materials of Sb ₂ O ₃ , P ₂ O ₅ , K ₂ O, V ₂ O ₅ , TeO ₂ , Ti ₂ O ₃ , PbO and MoO ₃ are used, Therefore, it is presumed that the same effect is obtained.

The above description has been made on the case where the low melting point oxide is added singly, but the same effect can be obtained even when these are added in combination.

Industrial availability

A major feature of the present invention resides in that the target bulk resistance value is reduced, conductivity is imparted, and the relative density is increased to 98% or more, thereby enabling stable DC sputtering. It is a remarkable effect that the controllability of the sputter, which is a feature of the DC sputtering, can be improved, and the sputtering efficiency can be improved by increasing the deposition rate. If necessary, RF sputtering is performed. In this case, however, an improvement in the film forming speed is observed.

In addition, it is possible to reduce particles (oscillation) and nodules generated during sputtering at the time of film formation, to reduce the quality deviation, to improve the mass productivity, and to stably manufacture an optical recording medium or the like having an optical disk protective film at low cost There is a remarkable effect. Therefore, the present invention is very useful as an optical thin film.

Since the thin film formed using the sputtering target of the present invention forms part of the structure of the optical information recording medium and ZnS is not used, the diffusion of the sulfur component into the recording layer material is lost, There is a remarkable effect.

When pure Ag or an Ag alloy having a high reflectance and high thermal conductivity is used for the reflective layer, the diffusion of the sulfur component to the reflective layer is also lost, causing the reflective layer to corrode and deteriorate, .

Furthermore, as a semi-transparent layer free from yellowing, a high-refractive index layer and a low-refractive index layer may be alternately laminated to form a semi-transparent layer having arbitrary optical characteristics. The target of the present invention is also useful as a low refractive index layer constituting a semi-transparent layer. It can also be applied to organic EL TV applications, electrodes for touch panels, sheet layers of hard disks, and the like.

Claims (1)

A sputtering target characterized by being described in the detailed description of the present invention.

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