JP2019077900A - Mn-W-Cu-O-BASED SPUTTERING TARGET, AND MANUFACTURING METHOD THEREOF - Google Patents

Abstract

To provide a Mn-W-Cu-O-based sputtering target capable of suppressing abnormal discharge, and performing stable deposition; and to provide a manufacturing method thereof.SOLUTION: There is provided a Mn-W-Cu-O-based sputtering target containing Mn, W, Cu and O in a component composition, and not containing Zn in the component composition. In the sputtering target, a relative density is 90% or more, and a specific resistance is 9×10Ω-cm or less.SELECTED DRAWING: None

Description

  The present invention particularly relates to a Mn-W-Cu-O-based sputtering target useful for forming a recording layer of an optical information recording medium, and a method of manufacturing the same.

  In recent years, in the field of optical information recording media (optical disks), with the increase of data to be handled, etc., it is required to increase the capacity of optical disks. Optical disks are roughly divided into read-only and recordable types, and the recordable type is further subdivided into two types: write-once type and rewritable type. Conventionally, organic dye materials have been widely studied as a write-once recording layer material, but with recent increase in capacity, inorganic materials are also widely studied.

  As a useful recording method using an inorganic material, by irradiating a recording layer containing an inorganic oxide having a low decomposition temperature with laser light, the physical properties of the recording layer are changed, and the optical constant is changed accordingly. There is a recording method. As the inorganic oxide material, palladium oxide is put to practical use, but since Pd is a noble metal and the material cost is high, development of a recording layer that can be realized at an inexpensive material cost instead of palladium oxide is desired .

  Recording layers made of manganese oxide-based materials have been developed to provide sufficiently good recording characteristics at low material costs. For example, Patent Document 1 discloses a recording layer containing manganese oxide and a plurality of inorganic elements such as a Mn-W-Zn-Cu-O-based recording layer, and a sputtering target used to form the recording layer. ing.

International Publication No. 2013/183277

  As a sputtering method for forming a recording layer composed of the above-mentioned manganese oxide and a plurality of inorganic elements such as W, a multi-source sputtering method using a plurality of sputtering targets composed of each element and a plurality of elements 1 There is a method of using a plurality of composite sputtering targets. Although the multi-source sputtering method is disclosed in Patent Document 1, the size of the apparatus is increased, which causes an increase in cost, and there is a defect that composition deviation easily occurs. Therefore, sputtering using one composite sputtering target is preferable. Further, from the viewpoint of productivity, it is desirable to use direct current (DC) sputtering rather than high frequency sputtering.

However, in the composite sputtering target made of manganese oxide and a plurality of inorganic elements such as W, insulating particles such as WMnO ₄ are easily included. In DC sputtering, since a direct current voltage is applied to the composite sputtering target, abnormal electric discharge (arching) may occur if sufficient conductivity can not be obtained due to the influence of insulating particles in the composite sputtering target. The abnormal discharge during the film formation damages the recording layer and causes a decrease in yield.

  The present invention has been made in view of the above, and an Mn-W-Cu-O-based sputtering target which suppresses abnormal discharge and enables stable film formation even with DC sputtering, and a method of manufacturing the same Intended to provide.

In order to achieve the above object, the present invention is a Mn-W-Cu-O-based sputtering target containing Mn, W, Cu, and O in the component composition, and the relative density is 90% or more. In addition, a sputtering target having a resistivity of 9 × 10 ⁻⁴ Ω · cm or less is provided.

  The component composition is 4 at% to 40 at% of Mn, 10 at% to 70 at% of W, and 10 at Cu, with respect to a total of 100 at% of Mn, W, and Cu. It may be atomic% to 40 atomic%.

  The sputtering target is selected from the group consisting of Mo, Nb, Mg, Ag, Ru, Ni, Zr, Sn, Bi, Co, Al, Pd, Ga, Te, V, Si, Ta, Cr, and Tb. The component composition may further include at least one or more elements.

  At least one selected from the group consisting of Mo, Nb, Mg, Ag, Ru, Ni, Zr, Sn, Bi, Ge, Co, Al, Pd, Ga, Te, V, Si, Ta, Cr, and Tb The total content of the elements of the species may be 8 atomic% to 70 atomic% with respect to a total of 100 atomic% of the constituent elements excluding O.

  The sputtering target may have a relative density of 94% or more.

  Moreover, this invention is a manufacturing method of said Mn-W-Cu-O type sputtering target, Comprising: The mixed powder containing a manganese containing powder, a tungsten containing powder, and a copper containing powder is wet-mixed for 10 hours or more A manufacturing method is provided that includes a mixing step, and a sintering step of sintering the mixed powder at a temperature above 750 ° C. after the mixing step.

  The manganese-containing powder may be a manganese oxide powder, the tungsten-containing powder may be a metallic tungsten powder, and the copper-containing powder may be a metallic copper powder.

  The mixed powder is selected from the group consisting of Mo, Nb, Mg, Ag, Ru, Ni, Zr, Sn, Bi, Co, Al, Pd, Ga, Te, V, Si, Ta, Cr, and Tb. It may further comprise a powder consisting of a single element or a compound of at least one element to be treated.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is DC sputtering, abnormal discharge can be suppressed and the Mn-W-Cu-O type sputtering target which enables stable film-forming, and its manufacturing method can be provided.

  Hereinafter, the present embodiment will be described in detail.

[Mn-W-Cu-O-based sputtering target]
The Mn-W-Cu-O-based sputtering target according to the present embodiment contains Mn, W, Cu, and O in the component composition, has a relative density of 90% or more, and has a specific resistance of 9 × 10 ^-4 Ω · cm or less. Hereinafter, the Mn-W-Cu-O-based sputtering target according to the present embodiment is simply referred to as a "target".

  There is no restriction | limiting in particular as a component ratio of the target which concerns on this embodiment, According to the objective, it can select suitably. For example, Mn is 4 to 40 at%, W is 10 to 70 at%, and Cu is 10 at% to a total of 100 at% of Mn, W, and Cu. It may be 40 atomic%.

  The target according to the present embodiment may contain other component compositions as necessary. When a target is used to form the recording layer of the information recording medium, for example, the transmittance, reflectance, and recording sensitivity of the recording layer can be adjusted by appropriately containing other elements. As an element, for example, Mo, Nb, Mg, Ag, Ru, Ni, Zr, Sn, Bi, Ge, Co, Al, Pd, Ga, Te, V, Si, Ta, Cr, and a group consisting of Tb There is at least one element selected.

  At least one selected from the group consisting of Mo, Nb, Mg, Ag, Ru, Ni, Zr, Sn, Bi, Ge, Co, Al, Pd, Ga, Te, V, Si, Ta, Cr, and Tb In the case of containing a kind of element, the total content rate thereof is, for example, 8 atomic% to 70 atomic% with respect to a total of 100 atomic% of constituent elements excluding O (oxygen) among constituent elements of the target. can do.

  In addition, the direction which does not contain Zn can raise the relative density of a target easily compared with the target containing Zn. Therefore, it is preferable that the target does not contain Zn.

The component composition of the target is evaluated by X-ray diffraction. Acquisition of the X-ray diffraction spectrum of a target can be performed according to a conventional method. For example, a spectrum may be acquired by scanning the target surface with θ-2θ using SmartLab manufactured by Rigaku Corporation. The measurement conditions of X-ray diffraction are appropriately determined depending on the target, and can be selected, for example, from the range of the following conditions.
X-ray source: Cu-Kα ray output setting: 20 kV to 100 kV, 10 mA to 100 mA
Angle range: 2θ = 5 ° -80 °
Scanning speed: 1 ° to 4 ° (2θ / min), continuous scan divergence slit: 0.5 ° to 2 °
Scattering slit: 0.5 ° to 2 °
Light receiving slit: 0.1 mm to 0.5 mm

The main diffraction peaks of the component composition of the target are detected in the following range.
D diffraction peak of W: 40.26 ° ± 0.3 °, 58.27 ° ± 0.3 °
Diffraction peaks of MnWO ₄ : 29.8 ° ± 0.3 °, 30.23 ° ± 0.3 °
Diffraction peaks of MnO: 35.16 ° ± 0.3 °, 40.99 ° ± 0.3 °, 59.18 ° ± 0.3 °
Diffraction peak of Cu: 43.47 ° ± 0.3 °, 50.67 ° ± 0.3 °

  In the present specification, relative density is used as an index indicating that the target according to the present embodiment has high density. The relative density of the target is 90% or more, preferably 94% or more. The higher the relative density of the target, the better.

In addition, relative density is the actual density after sintering a raw material part with respect to the virtual density at the time of assuming that the raw material powder | flour of a target was 100% filled. In order to calculate the relative density, first, dimension measurement and weight measurement of the target are performed to calculate an actual measurement density. Next, the relative density is calculated using the following formula.
Relative density (%) = (measured density of sintered body / virtual density) × 100

Further, in the present specification, specific resistance is used as an index indicating that the target according to the present embodiment has low resistance. The specific resistance of the target is 9 × 10 ⁻⁴ Ω · cm or less, preferably 8 × 10 ⁻⁴ Ω · cm or less, and more preferably 6 × 10 ⁻⁴ Ω · cm. The lower the specific resistance of the target, the better.

  The resistivity of the target can be measured using a resistivity meter. For example, it measures using a resistivity meter (MCP-T610 made from Mitsubishi Chemical Analytech Co., Ltd.).

  In addition, the shape of the target which concerns on this embodiment is not limited at all, It can be set as arbitrary shapes, such as disk shape, cylindrical shape, square plate shape, rectangular plate shape, square plate shape, and the use of a target It can be selected as appropriate. Further, the size (diameter in the case of a circle) of the width and depth of the target can be appropriately selected in the range of about mm order to m order according to the application of the target. For example, when the target is circular, the diameter is generally about 50 mm to 300 mm. The same applies to the thickness, but generally it is about 1 mm to 20 mm.

  When the target according to the present embodiment satisfies both the relative density and the specific resistance described above, it becomes a target capable of suppressing the occurrence of abnormal discharge when subjected to DC sputtering. , Confirmed by the present inventor. Furthermore, it was also confirmed that the occurrence of the abnormal discharge can not be sufficiently suppressed only by satisfying one of the conditions. The target is particularly useful for forming the recording layer of the optical information recording medium, but the application is not limited at all.

[Method of Manufacturing Mn-W-Cu-O-Based Sputtering Target]
Next, a method of manufacturing a target according to the present embodiment will be described. The manufacturing method according to the present embodiment includes a mixing step and a sintering step.

  First, in the mixing step, the mixed powder containing the manganese-containing powder, the tungsten-containing powder, and the copper-containing powder is wet-mixed for 10 hours or more.

As a manganese containing powder, it can select suitably according to the object, and the powder etc. which consist of a single substance or compound of Mn are mentioned. Among them, manganese oxide is preferable. The manganese oxide, for _example, can be used _{Mn 3 O 4, Mn 2 O} 3, MnO, MnO 2, MnO 3, Mn 2 O 7 and the like. These may be used alone or in combination of two or more. Among the above-mentioned manganese oxides, Mn ₃ O ₄ is preferable from the relationship between the sintering temperature and the melting point.
The average particle size of the manganese-containing powder is not particularly limited, and can be, for example, about 3 μm to 7 μm.

The tungsten-containing powder can be appropriately selected according to the purpose, and examples thereof include metallic tungsten powder and the like consisting of a single substance of W.
The average particle diameter of the tungsten-containing powder is not particularly limited, and can be, for example, about 2 μm to 5 μm.

As a copper containing powder, it can select suitably according to the object, for example, the metallic copper powder etc. which consist of a simple substance of Cu are mentioned.
It does not specifically limit as an average particle diameter of copper containing powder, For example, it can be about 1 micrometer-4 micrometers.

  In addition, depending on the desired purpose of the sputtering target to be produced, the above-mentioned manganese-containing powder, tungsten-containing powder and other powders other than copper-containing powder may be contained in the mixed powder. Other powders include, for example, Mo, Nb, Mg, Ag, Ru, Ni, Zr, Sn, Bi, Ge, Co, Al, Pd, Ga, Te, V, Si, Ta, Cr, and Tb. The powder which consists of a single substance or a compound of at least 1 sort (s) of element selected from a group is mentioned.

  There is no restriction | limiting in particular as a method of wet mixing, According to the objective, it can select suitably, For example, the wet mixing method etc. which used the conventionally well-known ball mill apparatus etc. are mentioned.

  The wet mixing time is 10 hours or more. The mixed powder can be sufficiently mixed by setting the mixing time to 10 hours or more. In particular, when using a manganese oxide as the manganese-containing powder, it leads to promoting the solid phase reaction of the manganese oxide during sintering to suppress the remaining of the crystalline phase of manganese oxide after sintering. The mixing time is preferably 12 hours or more, more preferably 16 hours or more, and still more preferably 20 hours or more. After mixing for 24 hours, the mixing effect is saturated.

Next, the mixed powder is sintered at a temperature of more than 750 ° C. in a sintering step.
The sintering method is not particularly limited and can be appropriately selected according to the purpose. For example, hot pressing in an inert gas atmosphere, hot isostatic pressing (HIP method), etc. It can be mentioned.

  By sintering the mixed powder at a temperature higher than 750 ° C., it is possible to suppress the remaining of the crystal phase of the insulator such as manganese oxide after sintering. The sintering temperature may be, for example, 800 ° C. or more, 850 ° C. or more, or 900 ° C. or more.

  The sintering time is not particularly limited and can be appropriately selected, and may be generally set to a sintering time of about 1 hour to 6 hours.

Further, the pressure to be applied at the time of sintering is not particularly limited and can be appropriately adjusted, but about 200 kgf / cm ² is preferable. Note that 1 kgf / cm ² corresponds to 98.1 kPa.

Through the above steps, a Mn-W-Cu-O-based sputtering target having a relative density of 90% or more and a specific resistance of 9 × 10 ⁻⁴ Ω · cm or less can be manufactured.

  In addition, the manufacturing method which concerns on this embodiment may also contain another process other than the said mixing process and a sintering process. Other processes include, for example, a process of forming a mixed powder, which is performed to form the shape of a sputtering target.

  Next, examples of the present invention will be described, but the present invention is not limited to these examples.

[Production of sputtering target]
Example 1
In Example 1, the following powders were prepared as raw material powders.
Mn ₃ O ₄ powder (Purity: 99.9% or more, average particle size: 5 μm)
W powder (Purity: 99.9% or more, average particle size: 2 μm)
Cu powder (Purity: 99.9% or more, average particle size: 1.5 μm)
The raw material powder was weighed such that the ratio of each contained metal was Mn: W: Cu = 30: 40: 30 (atomic%). The raw material powders weighed, zirconia balls (diameter 5 mm) three times the total weight of the raw material powders, and alcohol were placed in a container, and wet mixing was performed for 12 hours in a ball mill. After drying the mixed powder, it was passed through a 500 μm sieve. Then, a pressure of 200 kgf / cm ² was applied to the mixed powder at a sintering temperature of 900 ° C. for 2 hours, and hot pressing was performed in an inert gas atmosphere to produce a sputtering target. The shape of the sputtering target is a disk and the size is 50 mm in diameter.

Example 2
In Example 2, a sputtering target was produced in the same manner as in Example 1 except that the wet mixing time was 24 hours and the sintering temperature was 920 ° C.

Comparative Example 1
In Comparative Example 1, a sputtering target was produced in the same manner as in Example 1 except that the wet mixing time was 2 hours.

Comparative Example 2
In the comparative example 2, the sputtering target was produced by the method similar to Example 1 except sintering temperature having been 750 degreeC.

Comparative Example 3
In Comparative Example 3, a sputtering target was produced in the same manner as Example 1, except that the wet mixing time was 2 hours, and the sintering temperature was 750 ° C.

[Evaluation]
The relative density measurement, the specific resistance measurement, the measurement of the number of abnormal discharges, and the component evaluation of the crystal phase were performed on the sputtering targets manufactured in the above-described Examples 1 and 2 and Comparative Examples 1, 2 and 3. Each evaluation was performed as follows. The obtained evaluation results are shown in Table 1.

<Relative density>
In order to calculate the relative density of the sputtering target produced in the above-mentioned Examples 1 and 2 and Comparative Examples 1, 2 and 3, the dimensional measurement and weight measurement of the sputtering target were performed, and the actual measurement density was calculated. Next, the relative density was calculated using the following formula.
Relative density (%) = (measured density of sintered body / virtual density of sintered body) × 100

<Resistance>
The specific resistances of the sputtering targets produced in the above Examples 1 and 2 and Comparative Examples 1, 2 and 3 were measured using a resistivity meter (MCP-T610 manufactured by Mitsubishi Chemical Analytech Co., Ltd.).

<Measurement of abnormal discharge frequency>
The sputtering targets produced in the above-mentioned Examples 1 and 2 and Comparative Examples 1, 2 and 3 were bonded to a backing plate made of oxygen-free copper by In solder. The sputtering target was attached to a sputtering apparatus, vacuum evacuation was performed to 1 × 10 ⁻⁴ Pa or less, Ar gas and O ₂ gas were introduced, and the pressure in the apparatus was set to 0.3 Pa. The proportion of oxygen (O ₂ / Ar + O ₂ ) was 70%. Sputtering was performed for 30 minutes by applying a power of 5 W / cm ² from a DC power supply, and the number of abnormal discharges during sputtering was measured by an arcing counter.

  From the above results, it was confirmed that the Mn-W-Cu-O-based sputtering targets according to Examples 1 and 2 satisfying both the relative density and the specific resistance conditions have the number of abnormal discharges suppressed. In the case of Comparative Examples 1 and 2 satisfying either one of the relative density and the specific resistance, the number of abnormal discharges was reduced compared to Comparative Example 3 not satisfying either, but it was suppressed to the extent that practical use was possible. I can not say. Further, it was confirmed that the relative density and the specific resistance are influenced by the mixing time and the sintering temperature which are the preparation conditions of the sputtering target.

The present invention for achieving the above object, the Mn, and W, and Cu, seen containing a O, and the chemical composition, and there in Mn-W-Cu-O based sputtering target containing no Zn in the chemical composition The sputtering target has a relative density of 90% or more and a resistivity of 9 × 10 ⁻⁴ Ω · cm or less.

Claims (8)

An Mn—W—Cu—O-based sputtering target containing Mn, W, Cu, and O in the component composition,
A sputtering target having a relative density of 90% or more and a resistivity of 9 × 10 ⁻⁴ Ω · cm or less.   Mn is 4 at% to 40 at%, W is 10 at% to 70 at%, and Cu is at 10 at% to 40 with respect to a total of 100 at% of Mn, W, and Cu. The sputtering target according to claim 1, which is%.   At least one selected from the group consisting of Mo, Nb, Mg, Ag, Ru, Ni, Zr, Sn, Bi, Ge, Co, Al, Pd, Ga, Te, V, Si, Ta, Cr, and Tb The sputtering target of Claim 1 or 2 which further contains the above element in the said component composition.   At least one selected from the group consisting of Mo, Nb, Mg, Ag, Ru, Ni, Zr, Sn, Bi, Ge, Co, Al, Pd, Ga, Te, V, Si, Ta, Cr, and Tb The sputtering target according to claim 3, wherein the total content of the elements of the species is 8 atomic% to 70 atomic% with respect to a total of 100 atomic% of the constituent elements excluding O.   The sputtering target according to any one of claims 1 to 4, wherein the relative density is 94% or more. It is a manufacturing method of the Mn-W-Cu-O type sputtering target according to any one of claims 1 to 5,
A mixing step of wet mixing the mixed powder containing the manganese-containing powder, the tungsten-containing powder and the copper-containing powder for 10 hours or more;
And sintering the mixed powder at a temperature of more than 750 ° C. after the mixing step.   The method according to claim 6, wherein the manganese-containing powder is a manganese oxide powder, the tungsten-containing powder is a metallic tungsten powder, and the copper-containing powder is a metallic copper powder.   The mixed powder is selected from the group consisting of Mo, Nb, Mg, Ag, Ru, Ni, Zr, Sn, Bi, Co, Al, Pd, Ga, Te, V, Si, Ta, Cr, and Tb. The method according to claim 6 or 7, further comprising a powder consisting of a single element or a compound of at least one element to be treated.