JP2009235511A - Pd-W BASED SPUTTERING TARGET, AND METHOD FOR PRODUCING THE SAME - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive sputtering target which can substitute for a ruthenium target. <P>SOLUTION: The Pd-W based sputtering target comprises Pd and W as the main components. The target has a structure where W particles with the average particle diameter of 5 to 40 μm are dispersed into a Pd-W alloy matrix comprising 1 to 22 at% W, and the balance Pd with inevitable impurities, and the content of W to the whole target is controlled to 15 to 50 at%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a Pd—W-based sputtering target and a manufacturing method thereof, and more particularly to a Pd—W-based sputtering target that can be used as a substitute for a ruthenium target and a manufacturing method thereof.

  Ruthenium is used not only as a thin film electrode for semiconductor devices such as DRAM and FeRAM, but also as an intermediate layer of a recording medium such as a hard disk (for example, Patent Document 1).

  On the other hand, in a hard disk, a perpendicular magnetic recording method capable of stably performing high-density recording is becoming mainstream.

FIG. 1 schematically shows a cross section in the thickness direction of an example of a perpendicular magnetic recording type hard disk. As shown in FIG. 1, in the hard disk 100, a soft magnetic backing layer 104 is laminated on a substrate 102 such as glass, and an intermediate layer 106 is laminated on the soft magnetic backing layer 104. A CoCrPt—SiO ₂ recording layer (magnetic layer) 108 is laminated thereon. Each layer is formed by performing sputtering using a target corresponding to the composition.

The intermediate layer 106 is a ruthenium layer that functions to satisfactorily epitaxially grow the CoCrPt—SiO ₂ recording layer (magnetic layer) 108 and is formed by sputtering using a ruthenium target. By making the intermediate layer 106 a ruthenium layer, Co (001) is epitaxially grown on the Ru (001) orientation, and the recording layer (magnetic layer) 108 realizes a good C-axis orientation. Good perpendicular magnetic recording characteristics can be realized.

  Here, ruthenium is also used in an in-plane magnetic recording medium. In order to suppress thermal instability of recording, a ruthenium layer of several atomic layers is sandwiched between recording layers (magnetic layers). However, the thickness of the ruthenium layer used as the intermediate layer 106 in the perpendicular magnetic recording medium is 10 to 20 times the thickness of the ruthenium layer used in the in-plane magnetic recording medium.

  For this reason, the demand for ruthenium is rapidly increasing as the data recording system of hard disks is changed from the in-plane magnetic recording system to the perpendicular magnetic recording system, and the price of ruthenium is about two years earlier than before. It has soared about 10 times.

  In order to cope with the rise in the ruthenium price, the appearance of an inexpensive sputtering target that can replace the ruthenium target is awaited.

JP-A-2005-113174

  This invention is made | formed in view of this condition, Comprising: It aims at providing a cheap sputtering target which can substitute a ruthenium target, and its manufacturing method.

  As a result of earnest research and development to solve the above problems, the present inventors have found that the above problems can be solved by the following Pd—W-based sputtering target and a method for producing the same, and have reached the present invention.

  That is, the 1st aspect of the Pd-W type | system | group sputtering target which concerns on this invention is a Pd-W type | system | group sputtering target containing Pd and W as main components, Comprising: W contains 1-22at%, The remainder is Pd. And having a structure in which W particles having an average particle diameter of 5 to 40 μm are dispersed in a Pd—W alloy matrix made of inevitable impurities, and the W content with respect to the entire target is 15 to 50 at%. To do.

  The oxygen concentration in the Pd—W-based sputtering target is preferably 200 mass ppm or less.

  The Pd—W-based sputtering target can be suitably used for a perpendicular magnetic recording medium.

  The method for producing a Pd—W-based sputtering target according to the present invention is a Pd—W alloy powder containing W in an amount of 1 to 22 at%, the remainder being made of Pd and inevitable impurities by an atomizing method. A W powder having an average particle size of 5 to 40 μm is mixed with the W alloy powder so that the W content is 15 to 50 at% with respect to the entire powder to prepare a mixed powder. It is characterized by being molded by heating.

  The oxygen concentration in the obtained Pd—W-based sputtering target is preferably 200 ppm by mass or less.

  The atomizing method is preferably performed using argon gas or nitrogen gas.

  Moreover, it is preferable to shape | mold the produced said mixed powder by the discharge plasma sintering method.

  The obtained Pd—W-based sputtering target can be suitably used for a perpendicular magnetic recording medium.

  The 2nd aspect of the Pd-W type | system | group sputtering target which concerns on this invention is manufactured by the said manufacturing method.

  The Pd—W sputtering target according to the present invention can replace a ruthenium target and is inexpensive.

  When the oxygen concentration in the Pd—W-based sputtering target is suppressed to 200 mass ppm or less, sputtering using the target becomes better.

  According to the method for producing a Pd—W-based sputtering target according to the present invention, a ruthenium target can be substituted and an inexpensive sputtering target can be produced.

  Moreover, when it manufactures so that the oxygen concentration in the obtained Pd-W type | system | group sputtering target may be suppressed to 200 mass ppm or less, sputtering using this target will become a better thing.

  In addition, when the Pd—W alloy powder is manufactured by an atomizing method using argon gas or nitrogen gas, the oxygen concentration in the obtained Pd—W-based sputtering target can be further reduced. Furthermore, when the produced mixed powder is molded by the discharge plasma sintering method, the oxygen concentration in the obtained Pd—W-based sputtering target can be further suppressed.

  Hereinafter, embodiments of the present invention will be described in detail.

1. Components and Structure of Sputtering Target A Pd—W-based sputtering target according to an embodiment of the present invention is a Pd—W-based sputtering target containing Pd and W as main components, and contains 1 to 22 at% of W. It has a structure in which W particles having an average particle diameter of 5 to 40 μm are dispersed in a Pd—W alloy matrix composed of Pd and inevitable impurities, and the W content with respect to the entire target is 15 to 50 at%. It is characterized by.

1-1. About Pd Pd is a noble metal like Ru, and the atomic number of Pd is 46, which is close to the atomic number 44 of Ru, and characteristics such as atomic radius are similar to those of Ru. Furthermore, Pd is relatively inexpensive among noble metals. For this reason, Pd has a role of becoming a main component of a target that can substitute for a Ru target.

1-2. About W W introduces a stacking fault into the crystal structure of Pd having a face-centered cubic structure (fcc), and converts the crystal structure of Pd in an intermediate layer obtained by sputtering into a hexagonal close-packed structure (hcp) Ru. It has a role of approaching the crystal structure.

  The content of W with respect to the entire target needs to be 15 to 50 at%. If the W content is less than 15 at%, the amount of stacking faults introduced into the crystal structure of Pd is too small in the intermediate layer formed by sputtering using the target, and the Pd crystal in the intermediate layer The structure does not approach the hexagonal close-packed structure (hcp) of Ru, and a c-axis oriented recording layer (magnetic layer) cannot be formed on the intermediate layer. On the other hand, if the W content exceeds 50 at%, the influence of W characteristics is too great in the intermediate layer formed by sputtering using the target, and the recording is well c-axis oriented on the intermediate layer. A layer (magnetic layer) cannot be formed.

1-3. About Pd—W Alloy Matrix The Pd—W-based sputtering target according to an embodiment of the present invention contains 1 to 22 at% of W, and the average particle size in the Pd—W alloy matrix, the balance of which is Pd and inevitable impurities. It has a structure in which 5 to 40 μm W particles are dispersed, and the W content in the entire structure is 15 to 50 at%.

  The matrix Pd—W alloy contains 1 to 22 at% of W. For this reason, there is no place where only Pd exists in the entire target, and Pd always coexists with W. As a result, in the sputtering using the target according to the present embodiment, the speed at which a specific portion is scraped is not extremely increased, and the sputtering becomes favorable. If the content of W in the Pd—W alloy matrix is less than 1 at%, the rate at which a specific portion is scraped may be extremely increased during sputtering. On the other hand, in order for the content of W in the Pd—W alloy matrix to exceed 22 at%, the temperature of the molten metal needs to be heated to 2000 ° C. or higher, resulting in an increase in manufacturing cost.

1-4. About Dispersion Structure The Pd—W-based sputtering target according to this embodiment has a structure in which W particles having an average particle diameter of 5 to 40 μm are dispersed in a Pd—W alloy matrix.

  By having such a dispersion structure, even if the W content in the Pd—W alloy matrix is as low as 1 to 22 at%, the W content relative to the entire target can be increased as 15 to 50 at%.

  In addition, as will be described later in Examples, even with such a structure, a target (Reference Example 1) in which finer W particles are dispersed in a Pd—W alloy matrix and the structure becomes finer. In comparison, the present inventors have confirmed that there is no difference in the performance of the intermediate layer 106 (see FIG. 1) obtained by sputtering.

2. Manufacturing Method A manufacturing method of a Pd—W-based sputtering target according to an embodiment of the present invention is prepared by atomizing a Pd—W alloy powder containing 1 to 22 at% of W, the balance being Pd and inevitable impurities. The prepared Pd—W alloy powder was mixed with W powder having an average particle size of 5 to 40 μm so that the W content was 15 to 50 at% with respect to the entire powder, and then the prepared powder was used. The mixed powder is heated and molded under pressure.

  By adopting such a production method, the obtained target contains W in an amount of 5 to 40 μm in an average particle size of 5 to 40 μm in a Pd—W alloy matrix containing 1 to 22 at% of W and the balance being Pd and inevitable impurities. In addition, the oxygen concentration in the obtained Pd—W-based sputtering target can be suppressed to 200 ppm or less.

2-1. Production of Pd—W alloy powder By applying an atomizing method to a molten metal containing 1 to 22 at% of W and the balance being Pd and inevitable impurities, a Pd—W alloy powder having the same composition as the molten metal is produced. .

  By including 1 to 22 at% of W in the Pd—W alloy powder, there is no place where only Pd exists in the target obtained using the Pd—W alloy powder, and Pd always coexists with W. . As a result, in the sputtering using the obtained target, the speed at which a specific portion is cut is not extremely increased, and the sputtering using the target is satisfactory. When the content of W in the Pd—W alloy powder is less than 1 at%, in the sputtering using the obtained target, the rate at which a specific portion is scraped may be extremely increased. On the other hand, in order for the content of W in the Pd—W alloy powder to exceed 22 at%, the content of W in the molten metal used in the atomization method must also exceed 22 at%. It is necessary to heat the temperature of the molten metal to 2000 ° C. or more, which reduces production efficiency and is not economical.

  Further, any type of atomization method can be used, and any of a gas atomization method, a water atomization method, and a centrifugal force atomization method may be used.

  Since the Pd—W alloy powder is produced by the atomizing method, the raw material metal is once heated to a high temperature to become a molten metal. At that stage, an alkali metal such as Na or K, an alkaline earth metal such as Ca, oxygen or nitrogen is used. Gas impurities such as volatilize outside and are removed. For this reason, the amount of impurities in the obtained Pd—W alloy powder is reduced.

  Therefore, impurities in the target obtained by using the Pd—W alloy powder obtained by the atomization method are also reduced, and for example, the oxygen concentration can be suppressed to 200 mass ppm or less, and sputtering using the target is good. It will be something.

  In addition, when it produces by the gas atomizing method using argon gas or nitrogen gas, in the obtained Pd-W alloy powder, oxygen concentration can be restrained lower and it becomes a more favorable raw material powder.

2-2. About the mixed powder The Pd—W alloy powder obtained by the atomization method as described above was mixed with W powder having an average particle size of 5 to 40 μm so that the W content relative to the whole powder was 15 to 50 at%. A mixed powder is prepared.

  Here, in order to obtain a good target, it is necessary to reduce impurities such as oxygen, nitrogen, carbon, and sulfur in the W powder. For this purpose, the W powder needs to be heated in hydrogen. By heating W powder in hydrogen, it is possible to produce W powder with reduced impurities such as oxygen, nitrogen, carbon, and sulfur. However, W powder with reduced impurities has high activity and is not suitable. Since it is stable, if the average particle size is less than 5 μm, there is a risk of explosion and handling is difficult. On the other hand, if the average particle diameter of the W powder to be mixed exceeds 40 μm, the uniformity of W distribution in the obtained target is lowered, and uniform erosion during sputtering cannot be obtained.

  When the W content is 15 to 50 at% with respect to the entire mixed powder, the W content is 15 to 50 at% with respect to the entire target even in the obtained target. For this reason, the crystal structure of Pd in the intermediate layer formed by sputtering using the target approaches the hexagonal close-packed structure (hcp) of Ru, and a recording layer with a good c-axis orientation is formed on the intermediate layer. (Magnetic layer) can be formed.

2-3. Forming Method A method for forming the mixed powder by heating under pressure is not particularly limited. For example, a hot pressing method, a hot isostatic pressing method (HIP method), a discharge plasma sintering method (SPS method), etc. Can be used.

  However, since the amount of impurities in the target obtained can be reduced by forming using the discharge plasma sintering method (SPS method), the forming is performed using the discharge plasma sintering method (SPS method). It is more preferable. In spark plasma sintering, plasma is generated between powder particles during the sintering process, and oxygen, nitrogen, and the like adsorbed on the powder can be quickly dissociated. The amount of impurities in the target obtained by molding the mixed powder using the discharge plasma sintering method (SPS method) is, for example, an oxygen concentration of 200 mass ppm or less, a nitrogen concentration of 100 mass ppm or less, carbon The concentration can be suppressed to 200 mass ppm or less, and the sulfur concentration can be suppressed to 50 mass ppm or less.

3. As described above, in order for the W content in the Pd—W alloy powder to exceed 22 at%, the W content in the molten Pd—W alloy used in the atomization method also exceeds 22 at%. For this purpose, the temperature of the molten Pd—W alloy needs to be heated to 2000 ° C. or more, which reduces production efficiency and is not economical.

  Therefore, in the Pd—W-based sputtering target of this embodiment, W particles having an average particle size of 5 to 40 μm are contained in a Pd—W alloy matrix containing 1 to 22 at% of W and the balance being Pd and inevitable impurities. This structure eliminates the need to heat the molten Pd—W alloy to 2000 ° C. or higher when producing the Pd—W alloy powder.

  Moreover, in the manufacturing method of the Pd-W type | system | group sputtering target of this embodiment, the content of W is 15-50 at% with respect to the whole powder in Pd-W alloy powder whose content of W is 1-22 at%. W powder with an average particle size of 5 to 40 μm is mixed to prepare a mixed powder, and the prepared mixed powder is heated and molded under pressure to obtain a target. The temperature of the molten Pd—W alloy for producing a Pd—W alloy powder having a W content of 1 to 22 at% by the atomizing method may be less than 2000 ° C., without reducing the production efficiency.

  For this reason, in the manufacturing method of the present embodiment, a target containing 15 to 50 at% W with respect to the entire target can be produced efficiently and economically.

  The Pd—W-based sputtering target of the present embodiment has a structure in which W particles having an average particle diameter of 5 to 40 μm are dispersed in a Pd—W alloy matrix. Even if it has a structure, the intermediate layer 106 (FIG. 1) obtained by sputtering compared to a target (reference example 1) in which finer W particles are dispersed in a Pd—W alloy matrix and the structure is finer. The present inventor has confirmed that there is no difference in the performance of

4). About Use Since the layer formed using the Pd—W-based sputtering target according to the present embodiment approximates the ruthenium crystal structure, this Pd—W-based sputtering target is used as an intermediate layer of a perpendicular magnetic recording medium. Suitable for making. However, the Pd—W-based sputtering target according to the present embodiment is not limited to the use of manufacturing a perpendicular magnetic recording medium, and can be used for applications other than the manufacturing of a perpendicular magnetic recording medium as long as the ruthenium layer is used. be able to.

Example 1
Each metal was weighed so that the alloy composition would be Pd: 95 at% and W: 5 at%, heated to 1800 ° C. to form a molten Pd—W alloy, and Pd-5 at% W alloy powder was produced by a gas atomization method. It was 50 micrometers when the average particle diameter of the obtained alloy powder was measured by Microtrack MT3000 made by Nikkiso Co., Ltd.

  W powder with an average particle size of 30 μm was added to the obtained Pd-5 at% W alloy powder so that the W content was 30 at% with respect to the whole powder, and mixed for 4 hours by a ball mill to produce a mixed powder. did.

The obtained mixed powder was hot pressed under vacuum conditions of temperature: 1400 ° C., pressure: 20 MPa, time: 45 min, atmosphere: 5 × 10 ⁻² Pa or less to obtain a sintered body. The cross section of the obtained sintered body was observed with an electron microscope JSM-6500F manufactured by JEOL Ltd. FIG. 2 shows a photograph of the composition image taken with the electron microscope. In FIG. 2, white portions are W particles, black portions are Pd-5 at% W alloy, and the obtained sintered body has a structure in which W particles are dispersed in a Pd-5 at% W alloy matrix. I understand that.

  Next, the obtained sintered body was processed into a diameter of 180 mm and a thickness of 7 mm to obtain a sputtering target. About the obtained sputtering target, when oxygen concentration was measured with the TC-600 type | mold oxygen-nitrogen simultaneous analyzer made from LECO, it was 165 ppm.

  Next, sputtering was performed using a sputtering apparatus manufactured by Canon Anelva Co., Ltd. using the obtained sputtering target to form the intermediate layer shown in FIG. 1, and a hard disk having the structure shown in FIG. 1 was produced. When the recording characteristics of the produced hard disk were evaluated, there was no difference in recording characteristics as compared with the hard disk using ruthenium Ru for the intermediate layer. In the evaluation of the recording characteristics of the hard disk in Example 1 and the following Examples 2 to 11, Reference Example 1, and Comparative Examples 1 to 6, there is a difference in recording characteristics as compared with the hard disk using ruthenium Ru as the intermediate layer. Table 1 shows ◯ when there is no recording medium, and x when recording characteristics are inferior to a hard disk using ruthenium Ru as an intermediate layer.

(Example 2)
Each of the metals was weighed so that the alloy composition was Pd: 90 at% and W: 10 at%, and a mixed powder, a sintered body, While producing the sputtering target and the hard disk, they were evaluated.

  The average particle diameter of the obtained Pd-10 at% W alloy powder is 50 μm, and the structure of the obtained sintered body is a structure in which W particles are dispersed in a Pd-10 at% W alloy matrix. The oxygen concentration of the sputtering target was 145 ppm, and the recording characteristics of the obtained hard disk were not different from those of the hard disk using ruthenium Ru as the intermediate layer.

(Example 3)
Each of the metals was weighed so that the alloy composition was Pd: 85 at% and W: 15 at%, and a mixed powder, a sintered body, While producing the sputtering target and the hard disk, they were evaluated.

  The average particle diameter of the obtained Pd-15 at% W alloy powder is 50 μm, and the structure of the obtained sintered body is a structure in which W particles are dispersed in a Pd-15 at% W alloy matrix. The oxygen concentration of the sputtering target was 112 ppm, and the recording characteristics of the obtained hard disk were not different from those of the hard disk using ruthenium Ru as the intermediate layer.

Example 4
Each of the metals was weighed so that the alloy composition would be Pd: 80 at%, W: 20 at%, and a mixed powder, a sintered body, While producing the sputtering target and the hard disk, they were evaluated.

  The average particle diameter of the obtained Pd-20 at% W alloy powder is 50 μm, and the structure of the obtained sintered body is a structure in which W particles are dispersed in a Pd-20 at% W alloy matrix. The oxygen concentration of the sputtering target was 89 ppm, and the recording characteristics of the obtained hard disk were not different from those of the hard disk using ruthenium Ru as the intermediate layer.

(Example 5)
Except that W powder having an average particle size of 30 μm was added to the Pd-5 at% W alloy powder obtained by the gas atomization method so that the W content was 45 at% relative to the whole powder, the same as in Example 1. Then, the mixed powder, the sintered body, the sputtering target, and the hard disk were prepared and evaluated.

  The average particle diameter of the obtained Pd-5 at% W alloy powder is 50 μm, and the structure of the obtained sintered body is a structure in which W particles are dispersed in a Pd-5 at% W alloy matrix. The oxygen concentration of the sputtering target was 173 ppm, and the recording characteristics of the obtained hard disk were not different from those of the hard disk using ruthenium Ru as the intermediate layer.

(Example 6)
Except that W powder having an average particle diameter of 30 μm was added to the Pd-5 at% W alloy powder obtained by the gas atomization method so that the W content was 35 at% with respect to the whole powder, the same as in Example 1. Then, the mixed powder, the sintered body, the sputtering target, and the hard disk were prepared and evaluated.

  The average particle diameter of the obtained Pd-5 at% W alloy powder is 50 μm, and the structure of the obtained sintered body is a structure in which W particles are dispersed in a Pd-5 at% W alloy matrix. The oxygen concentration of the sputtering target was 175 ppm, and the recording characteristics of the obtained hard disk were not different from those of the hard disk using ruthenium Ru as the intermediate layer.

(Example 7)
Except that W powder having an average particle size of 30 μm was added to Pd-5 at% W alloy powder obtained by the gas atomization method so that the W content was 25 at% with respect to the whole powder, the same as in Example 1. Then, the mixed powder, the sintered body, the sputtering target, and the hard disk were prepared and evaluated.

  The average particle diameter of the obtained Pd-5 at% W alloy powder is 50 μm, and the structure of the obtained sintered body is a structure in which W particles are dispersed in a Pd-5 at% W alloy matrix. The oxygen concentration of the sputtering target was 162 ppm, and the recording characteristics of the obtained hard disk were not different from those of the hard disk using ruthenium Ru as the intermediate layer.

(Example 8)
Except that W powder having an average particle size of 30 μm was added to the Pd-5 at% W alloy powder obtained by the gas atomization method so that the W content was 20 at% relative to the whole powder, the same as in Example 1. Then, the mixed powder, the sintered body, the sputtering target, and the hard disk were prepared and evaluated.

  The average particle diameter of the obtained Pd-5 at% W alloy powder is 50 μm, and the structure of the obtained sintered body is a structure in which W particles are dispersed in a Pd-5 at% W alloy matrix. The oxygen concentration of the sputtering target was 161 ppm, and the recording characteristics of the obtained hard disk were not different from those of the hard disk using ruthenium Ru as the intermediate layer.

Example 9
Except for adding W powder having an average particle diameter of 25 μm to the Pd-5 at% W alloy powder obtained by the gas atomization method so that the W content is 30 at% with respect to the whole powder, the same as in Example 1. Then, the mixed powder, the sintered body, the sputtering target, and the hard disk were prepared and evaluated.

  The average particle diameter of the obtained Pd-5 at% W alloy powder is 50 μm, and the structure of the obtained sintered body is a structure in which W particles are dispersed in a Pd-5 at% W alloy matrix. The oxygen concentration of the sputtering target was 173 ppm, and the recording characteristics of the obtained hard disk were not different from those of the hard disk using ruthenium Ru as the intermediate layer.

(Example 10)
Except that W powder having an average particle size of 15 μm was added to the Pd-5 at% W alloy powder obtained by the gas atomization method so that the W content was 30 at% relative to the whole powder, the same as in Example 1. Then, the mixed powder, the sintered body, the sputtering target, and the hard disk were prepared and evaluated.

  The average particle diameter of the obtained Pd-5 at% W alloy powder is 50 μm, and the structure of the obtained sintered body is a structure in which W particles are dispersed in a Pd-5 at% W alloy matrix. The oxygen concentration of the sputtering target was 180 ppm, and the recording characteristics of the obtained hard disk were not different from those of the hard disk using ruthenium Ru as the intermediate layer.

Example 11
Except for adding W powder with an average particle diameter of 8 μm to the Pd-5 at% W alloy powder obtained by the gas atomization method so that the W content is 30 at% with respect to the whole powder, the same as in Example 1. Then, the mixed powder, the sintered body, the sputtering target, and the hard disk were prepared and evaluated.

  The average particle diameter of the obtained Pd-5 at% W alloy powder is 50 μm, and the structure of the obtained sintered body is a structure in which W particles are dispersed in a Pd-5 at% W alloy matrix. The oxygen concentration of the sputtering target was 186 ppm, and the recording characteristics of the obtained hard disk were not different from those of the hard disk using ruthenium Ru as the intermediate layer.

(Reference Example 1)
Each metal was weighed so that the alloy composition would be Pd: 70 at%, W: 30 at%, heated to 2200 ° C. to obtain a Pd-30 at% W alloy melt, and a Pd-30 at% W alloy powder was produced by gas atomization method. . When the average particle diameter of the obtained Pd-30 at% W alloy powder was measured with a Microtrac MT3000 manufactured by Nikkiso Co., Ltd. in the same manner as in Example 1, it was 50 μm.

In this reference example 1, W powder was not mixed with the obtained atomized powder (Pd-30 at% W alloy powder), and only the obtained Pd-30 at% W alloy powder was used, as in Example 1. Were subjected to hot pressing under the following conditions: temperature: 1400 ° C., pressure: 20 MPa, time: 45 min, atmosphere: 5 × 10 ⁻² Pa or less to obtain a sintered body. The cross section of the obtained sintered body was observed with an electron microscope JSM-6500F manufactured by JEOL Ltd. in the same manner as in Example 1. FIG. 3 shows a photograph of the composition image taken with the electron microscope. In FIG. 3, white portions are W particles, black portions are Pd—W alloys, and the obtained sintered body has a structure in which fine W particles are dispersed in a Pd—W alloy matrix. Compared to FIG. 2, it can be seen that the structure is finer.

  The obtained sintered body was processed in the same manner as in Example 1 to obtain a sputtering target. When the oxygen concentration of the obtained sputtering target was measured in the same manner as in Example 1, it was 60 ppm.

  Sputtering was performed using the obtained sputtering target, and the intermediate layer shown in FIG. 1 was formed in the same manner as in Example 1 to produce a hard disk having the structure shown in FIG. When the recording characteristics of the produced hard disk were evaluated, there was no difference in recording characteristics as compared with the hard disk using ruthenium Ru for the intermediate layer, and there was no difference in recording characteristics compared with the hard disks in Examples 1-11. .

(Comparative Example 1)
Pure Pd was heated to 2000 ° C. to form a molten metal, and Pd powder was produced by a gas atomization method. When the average particle diameter of the obtained Pd powder was measured with Microtrac MT3000 manufactured by Nikkiso Co., Ltd. in the same manner as in Example 1, it was 50 μm.

  W powder having an average particle size of 30 μm was added to the obtained Pd powder so that the W content was 45 at% with respect to the whole powder, and mixed for 4 hours by a ball mill to prepare a mixed powder.

The obtained mixed powder was hot pressed under the same conditions as in Example 1, temperature: 1400 ° C., pressure: 20 MPa, time: 45 min, atmosphere: 5 × 10 ⁻² Pa or less, A sintered body was obtained. The cross section of the obtained sintered body was observed with an electron microscope JSM-6500F manufactured by JEOL Ltd. in the same manner as in Example 1. FIG. 4 shows a photograph of the composition image taken with the electron microscope. In FIG. 4, the white part is W and the black part is Pd particles, and the obtained sintered body has a structure in which Pd particles are dispersed in a W matrix.

  The obtained sintered body was processed in the same manner as in Example 1 to obtain a sputtering target. When the oxygen concentration of the obtained sputtering target was measured in the same manner as in Example 1, it was 582 ppm.

  Sputtering was performed using the obtained sputtering target, and the intermediate layer shown in FIG. 1 was formed in the same manner as in Example 1 to produce a hard disk having the structure shown in FIG. When the recording characteristics of the produced hard disk were evaluated, the recording characteristics were inferior to the hard disk using ruthenium Ru as the intermediate layer, and the recording characteristics were inferior to the hard disks in Examples 1-11.

(Comparative Example 2)
A mixed powder in the same manner as in Comparative Example 1 except that W powder having an average particle size of 30 μm was added to the Pd powder obtained by the gas atomization method so that the W content was 35 at% with respect to the whole powder. While producing a sintered compact, a sputtering target, and a hard disk, they were evaluated.

  The average particle diameter of the obtained Pd powder is 50 μm, and the structure of the obtained sintered body is a structure in which Pd particles are dispersed in a W matrix. The oxygen concentration of the obtained sputtering target is 254 ppm. It was. The recording characteristics of the obtained hard disk were inferior to those of the hard disk using ruthenium Ru as the intermediate layer, and inferior to the hard disks in Examples 1-11.

(Comparative Example 3)
A mixed powder in the same manner as in Comparative Example 1 except that W powder having an average particle size of 30 μm was added to the Pd powder obtained by the gas atomization method so that the W content was 30 at% with respect to the whole powder. While producing a sintered compact, a sputtering target, and a hard disk, they were evaluated.

  The average particle diameter of the obtained Pd powder was 50 μm, and the structure of the obtained sintered body was a structure in which Pd particles were dispersed in a W matrix. The oxygen concentration of the obtained sputtering target was 380 ppm. It was. The recording characteristics of the obtained hard disk were inferior to those of the hard disk using ruthenium Ru as the intermediate layer, and inferior to the hard disks in Examples 1-11.

(Comparative Example 4)
A mixed powder in the same manner as in Comparative Example 1 except that W powder having an average particle size of 30 μm was added to the Pd powder obtained by the gas atomization method so that the W content was 25 at% with respect to the whole powder. While producing a sintered compact, a sputtering target, and a hard disk, they were evaluated.

  The average particle diameter of the obtained Pd powder is 50 μm, and the structure of the obtained sintered body is a structure in which Pd particles are dispersed in a W matrix. The oxygen concentration of the obtained sputtering target is 456 ppm. It was. The recording characteristics of the obtained hard disk were inferior to those of the hard disk using ruthenium Ru as the intermediate layer, and inferior to the hard disks in Examples 1-11.

(Comparative Example 5)
A mixed powder in the same manner as in Comparative Example 1 except that W powder having an average particle size of 30 μm was added to the Pd powder obtained by the gas atomization method so that the W content was 20 at% with respect to the whole powder. While producing a sintered compact, a sputtering target, and a hard disk, they were evaluated.

  The average particle size of the obtained Pd powder was 50 μm, and the structure of the obtained sintered body was a structure in which Pd particles were dispersed in a W matrix. The oxygen concentration of the obtained sputtering target was 468 ppm. It was. The recording characteristics of the obtained hard disk were inferior to those of the hard disk using ruthenium Ru as the intermediate layer, and inferior to the hard disks in Examples 1-11.

(Comparative Example 6)
A mixed powder in the same manner as in Comparative Example 1 except that W powder having an average particle size of 60 μm was added to the Pd powder obtained by the gas atomization method so that the W content was 30 at% with respect to the whole powder. While producing a sintered compact, a sputtering target, and a hard disk, they were evaluated.

  The average particle diameter of the obtained Pd powder is 50 μm, and the structure of the obtained sintered body is a structure in which Pd particles are dispersed in a W matrix. The oxygen concentration of the obtained sputtering target is 382 ppm. It was. The recording characteristics of the obtained hard disk were inferior to those of the hard disk using ruthenium Ru as the intermediate layer, and inferior to the hard disks in Examples 1-11.

  In Examples 1 to 11 that are within the scope of the present invention, the oxygen concentration of the obtained sputtering target is 200 ppm or less, and the recording characteristics of the obtained hard disk use ruthenium Ru for the intermediate layer. There was no difference compared to the old hard disk, and good results were obtained.

  On the other hand, the atomized powder mixed with the W powder is not a Pd—W alloy powder having a predetermined composition but a Pd powder. In Comparative Examples 1 to 6, which are outside the scope of the present invention, all obtained sputtering targets The oxygen concentration of the obtained hard disk exceeded 200 ppm, and the recording characteristics of the obtained hard disk were inferior to those of the hard disk using ruthenium Ru for the intermediate layer, and good results were not obtained.

The figure which shows typically the thickness direction section about an example of the perpendicular magnetic recording system hard disk Electron micrograph of the sintered body in Example 1 (composition image) Electron micrograph (composition image) of the sintered body in Reference Example 1. Electron micrograph (composition image) of the sintered body in Comparative Example 1

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Hard disk 102 ... Base material 104 ... Soft magnetic backing layer 106 ... Intermediate | middle layer 108 ... Recording layer (magnetic layer)

Claims (9)

A Pd—W-based sputtering target containing Pd and W as main components,
It has a structure in which W particles having an average particle diameter of 5 to 40 μm are dispersed in a Pd—W alloy matrix containing W in an amount of 1 to 22 at% and the balance being Pd and inevitable impurities. A Pd—W sputtering target characterized in that the amount is 15 to 50 at%. In claim 1,
The oxygen concentration in the said Pd-W type | system | group sputtering target is 200 mass ppm or less, The Pd-W type | system | group sputtering target characterized by the above-mentioned. In claim 1 or 2,
A Pd—W-based sputtering target for use in a perpendicular magnetic recording medium.   A Pd—W alloy powder containing 1 to 22 at% of W and the balance of Pd and unavoidable impurities is prepared by an atomizing method, and the produced Pd—W alloy powder has a W content of 15 to 15%. A mixed powder is prepared by mixing W powder having an average particle diameter of 5 to 40 μm so as to be 50 at%, and then the formed mixed powder is heated and molded under pressure. Target manufacturing method. In claim 4,
The manufacturing method of the Pd-W type | system | group sputtering target characterized by making oxygen concentration in the obtained Pd-W type | system | group sputtering target 200 mass ppm or less. In claim 4 or 5,
The atomizing method is performed using argon gas or nitrogen gas, and a method for producing a Pd—W sputtering target. In any one of Claims 4-6,
A method for producing a Pd—W-based sputtering target, wherein the produced mixed powder is formed by a discharge plasma sintering method. In any one of Claims 4-7,
The obtained Pd—W-based sputtering target is for a perpendicular magnetic recording medium. A method for producing a Pd—W-based sputtering target.   A Pd—W-based sputtering target produced by the production method according to claim 4.