WO2014141789A1

WO2014141789A1 - Sputtering target for forming magnetic recording film, and carbon raw material used for production of said target

Info

Publication number: WO2014141789A1
Application number: PCT/JP2014/053005
Authority: WO
Inventors: 真一荻野; 中村　祐一郎
Original assignee: Jx日鉱日石金属株式会社
Priority date: 2013-03-11
Filing date: 2014-02-10
Publication date: 2014-09-18
Also published as: JP6062586B2; JPWO2014141789A1; JP5973056B2; SG11201503691WA; JP2016173871A

Abstract

A carbon powder which can be used for the production of a sputtering target for forming a magnetic recording film, said carbon powder being characterized by having a fluorine content of 50 ppm by weight or more; and a sputtering target for forming a magnetic recording film, said sputtering target being characterized by being produced by a sintering method using the carbon powder. The present invention addresses the problem of enabling the production of a magnetic thin film having a granular structure without requiring the use of an expensive cosputtering device, and also addresses the problem of providing a highly dense sputtering target in which the amount of particles generated during sputtering is reduced.

Description

Sputtering target for forming a magnetic recording film and carbon raw material used for manufacturing the target

The present invention relates to a sputtering target used for forming a granular magnetic thin film on a magnetic recording medium, and a carbon raw material used for manufacturing the target.

In the field of magnetic recording typified by a hard disk drive, a material based on a ferromagnetic metal such as Co, Fe, or Ni is used as a material for a magnetic thin film in a magnetic recording medium. For example, a Co—Cr-based or Co—Cr—Pt-based ferromagnetic alloy containing Co as a main component has been used for a magnetic thin film of a hard disk employing an in-plane magnetic recording method. In addition, hard magnetic thin films employing perpendicular magnetic recording that have been put into practical use in recent years often use a composite material composed of Co—Cr—Pt-based ferromagnetic alloy mainly composed of Co and non-magnetic inorganic particles. It has been. The magnetic thin film is often produced by sputtering a sputtering target containing the above material as a component with a DC magnetron sputtering apparatus because of its high productivity.

Recording density of a hard disk is rapidly increasing year by year, it is believed to the future from the surface density of 600Gbit / in ² the current reaches 1 Tbit / in ^2. When the recording density reaches 1 Tbit / in ² , the size of the recording bit becomes less than 10 nm. In that case, superparamagnetization due to thermal fluctuation is expected to be a problem, and magnetic recording media currently used It is expected that a material obtained by adding Pt to a material such as a Co—Cr base alloy to increase the magnetocrystalline anisotropy is not sufficient. This is because magnetic particles that behave stably as ferromagnetism with a size of 10 nm or less need to have higher crystal magnetic anisotropy.

For the above reasons, an FePt phase having an L1 ₀ structure has attracted attention as a material for an ultrahigh density recording medium. The FePt phase having the L1 ₀ structure is expected to be a material suitable for application as a magnetic recording medium since it has high crystal magnetic anisotropy and excellent corrosion resistance and oxidation resistance. In the case where the FePt phase is used as a material for an ultra-high density recording medium, there has been a development of a technique for aligning and dispersing the ordered FePt magnetic particles in as high a density as possible in a magnetically isolated state. It has been demanded.

For this reason, a granular structure magnetic thin film of FePt magnetic particles are isolated by a non-magnetic material such oxides or carbon having an L1 ₀ structure, as for a magnetic recording medium of the next generation hard disk employing a thermally assisted magnetic recording method Proposed. This granular structure magnetic thin film has a structure in which magnetic particles are magnetically insulated by interposition of a nonmagnetic substance. Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, and Patent Document 5 can be cited as magnetic recording media having a magnetic thin film having a granular structure and related documents.

As the granular magnetic thin film having an FePt phase having the L1 ₀ structure, a magnetic thin film containing 10 to 50% by volume of C as a non-magnetic substance has been attracting attention because of its high magnetic properties. It is known that such a granular structure magnetic thin film is produced by simultaneously sputtering an Fe target, a Pt target, and a C target, or by simultaneously sputtering an Fe—Pt alloy target and a C target. However, in order to simultaneously sputter these sputtering targets, an expensive simultaneous sputtering apparatus is required.

In general, when a sputtering target containing a nonmagnetic material in an alloy is sputtered by a sputtering apparatus, abnormal discharge occurs due to inadvertent detachment of the nonmagnetic material or vacancies contained in the sputtering target at the time of sputtering. There is a problem that (dust attached to the substrate) is generated. In order to solve this problem, it is necessary to increase the adhesion between the nonmagnetic material and the base alloy and to increase the density of the sputtering target. Generally, a sputtering target material in which a nonmagnetic material is contained in an alloy is produced by a powder sintering method. However, when Fe—Pt contains a large amount of C, it is difficult to obtain a high-density sintered body because C is a difficult-to-sinter material.

In addition, the present inventor previously used a technique for producing a high-density sputtering target by uniformly dispersing C particles, which are nonmagnetic materials, in a base metal in a Fe—Pt-based sputtering target in which C particles are dispersed. (Patent Document 6). According to this technique, aggregation of C particles can be suppressed, but it is difficult to improve the sinterability of C particles because C particles are hardly sintered materials. Patent Documents 7 to 8 disclose a technique in which, in a sputtering target for forming a magnetic recording medium film, by dispersing the C phase in the FePt alloy phase, abnormal discharge during sputtering and differences due to the location of the sputtering rate can be suppressed. However, there is no mention about improvement of sinterability of C (carbon).

JP 2000-306228 A JP 2000-31329 A JP 2008-59733 A JP 2008-169464 A JP 2004-152471 A International Publication No. 2012/086335 Pamphlet JP 2012-102387 A JP 2012-214874 A

An object of the present invention is to provide an Fe—Pt-based sputtering target in which C particles are dispersed, which makes it possible to produce a granular structure magnetic thin film without using an expensive co-sputtering apparatus. It is an object to provide a sputtering target in which the amount of generated particles is reduced.

In order to solve the above problems, the present inventor has conducted intensive research, and as a result, it is possible to improve the difficulty of sintering carbon by adjusting the fluorine content in the carbon raw material that is a non-magnetic material. I found. In addition, it has been found that the sputtering target produced in this manner can prevent the carbon from falling off and can suggest the generation amount of particles, so that the yield during film formation can be improved.

Based on such knowledge, the present invention
1) Carbon powder used for producing a sputtering target for forming a magnetic recording film, wherein the fluorine content is 50 wtppm or more,
2) The carbon powder according to 1) above, wherein the median diameter is 0.1 to 20 μm,
3) A sputtering target for forming a magnetic recording film, wherein the carbon powder described in 1) or 2) above is used as a raw material for the target, and is produced by a powder sintering method,
4) The sputtering target for forming a magnetic recording film according to 3) above, wherein the fluorine content is less than 0.05 wtppm,
5) After mixing the raw material powder containing the carbon powder described in 1) or 2) above, the mixed powder is molded and sintered, and the obtained sintered body is further subjected to isotropic hot pressing, And a method of manufacturing a sputtering target for forming a magnetic recording film, characterized by processing into a target shape.

The Fe—Pt sputtering target in which C particles are dispersed according to the present invention enables the formation of a granular structure magnetic thin film without using an expensive simultaneous sputtering apparatus, and further reduces the amount of particles generated during sputtering. It has an excellent effect of providing a target.

The present invention is characterized in that the fluorine (F) content in the carbon powder used for producing the sputtering target for forming a magnetic recording film is 50 wtppm or more. Carbon powder contains fluorine (F) as an impurity, and usually, a raw material with few such impurities is used.
Here, fluorine in the carbon raw material exists in a form bonded to carbon, but when this is exposed to a high temperature, a reaction (defluorination reaction) that breaks the bond occurs. At this time, a reaction occurs in which the carbons are bonded to each other by an extra bond. According to the present invention, by using a carbon raw material powder containing a relatively large amount of fluorine in advance, the carbon-carbon bonding reaction is promoted during the defluorination reaction, and the difficulty of carbon sinterability can be improved.

The present invention also includes the case where the median diameter of the carbon raw material powder used for manufacturing the sputtering target for forming a magnetic recording film is 0.1 to 20 μm. In order to promote the bonding between the carbon raw materials by the above defluorination reaction, the surfaces of the carbon powders having a carbon-fluorine bond are preferably in contact as much as possible. If the median diameter of the carbon raw material powder is less than 0.1 μm, the amount of fluorine relative to the number of carbon particles may be insufficient. On the other hand, if the median diameter of the carbon raw material powder exceeds 20 μm, the carbon raw material itself may cause abnormal discharge, which is not preferable. Therefore, the median diameter of the carbon raw material powder is preferably 0.1 to 20 μm.

The present invention also provides a magnetic recording film by sintering a carbon raw material powder having a fluorine (F) content of 50 wtppm or more and, if necessary, a median diameter of 0.1 to 20 μm. A sputtering target is manufactured. By using the carbon raw material powder having such characteristics, it is possible to promote the sintering of carbons, and therefore it is possible to suppress the generation of particles by dropping carbon from the target during sputtering. . It should be understood that the present invention is characterized by the fluorine content and the like contained in the carbon raw material powder, and that known means can be used as the means for sintering.

The present invention also includes the case where the fluorine content in the sputtering target for forming a magnetic recording film is less than 0.05 wtppm. The fluorine contained in the carbon raw material powder is reduced by being exposed to a high temperature during sintering to cause a defluorination reaction. This means, on the other hand, that the bonding (sintering) between carbons is promoted. Therefore, by adjusting the fluorine content in the carbon raw material powder and the fluorine content in the target, it is possible to quantitatively control the carbon-carbon bond amount. If the fluorine content in the target is 0.05 wtppm or more, fluorine may cause abnormal discharge and cause generation of particles, which is not preferable.

In the present invention, a sputtering target for forming a magnetic recording film can be one having a known composition. For example, in a Fe—Pt alloy-based target in which C particles are dispersed, a Pt content of 20 to 50 atomic ratio and a C content of 20 to 50 atomic ratio can be used. In the present invention, one or more metal elements selected from Ag, Cu, Au, B, Ru, and Mn can be added as an additive, and Si, Ti, Cr, Co, Fe, and B can be added. An oxide or nitride of one or more elements selected from Ta, Ga, Mn, Zn, Nb, Al, Mg, Zr, Y, and Ca can be added. Thereby, the produced magnetic thin film can obtain good magnetic properties.

The sputtering target of the present invention is produced by a powder sintering method. In preparation, each raw material powder (Fe powder, Pt powder, C powder, etc.) is prepared. Here, as the C powder, it is important to use a C powder containing a predetermined amount of fluorine, a C powder preliminarily fluorinated, or a mixed powder of a fluorinated C powder and other carbon raw materials.
C powder having a particle size of 0.1 μm or more and 20 μm or less is desirably used. If the particle size of the raw material C powder is too small, there is a problem that the amount of fluorine is insufficient. On the other hand, if the particle size of the raw material powder is large, it is difficult to finely disperse the C particles in the alloy, causing abnormal discharge. There is a risk of becoming. It is desirable to use other raw material powders of 0.1 μm or more and 20 μm or less.
Further, an alloy powder (such as Fe—Pt powder) may be used as the raw material powder. In particular, an alloy powder containing Pt is effective for reducing the amount of oxygen in the raw material powder, although it depends on its composition. Also when using alloy powder, it is desirable to use a powder having a particle size of 0.1 to 20 μm.

Then, the above powder is weighed so as to have a desired composition and mixed using a known method such as a mortar. The mixed powder thus obtained is molded and sintered with a hot press. In addition to hot pressing, a plasma discharge sintering method or a hot isostatic pressing method can also be used. The holding temperature at the time of sintering depends on the composition of the sputtering target, but in most cases, it is in the temperature range of 900 to 1400 ° C.

Next, isotropic hot pressing is performed on the sintered body taken out from the hot press. Isotropic hot pressing is effective for improving the density of the sintered body. In most cases, the holding temperature during the isotropic hot pressing is in the temperature range of 900 to 1400 ° C. depending on the composition of the sintered body. Further, the pressure is set to 100 Mpa or more.
The sputtering target of the present invention can be produced by processing the sintered body thus obtained into a desired shape using a lathe or the like.

As described above, a sputtering target for forming a magnetic recording film with improved sinterability of carbon can be produced. The sputtering target of the present invention thus produced is less likely to generate particles during sputtering and is useful as a sputtering target used for forming a granular structure magnetic thin film.

Hereinafter, description will be made based on examples and comparative examples. In addition, a present Example is an example to the last, and is not restrict | limited at all by this example. In other words, the present invention is limited only by the scope of the claims, and includes various modifications other than the examples included in the present invention.

(Example 1)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. For the C powder, natural graphite containing 150 wtppm of fluorine was used. Further, the median diameter (D50) of the C powder was 6.1 μm. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-30Pt-40C
The fluorine content was analyzed by GDMS (glow discharge mass spectrometry). The same applies to the following examples and comparative examples.

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot press conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 1400 ° C., and a holding time of 2 hours, and pressurization was performed at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a temperature increase rate of 300 ° C./hour, a holding temperature of 1100 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of the temperature increase to 1100 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by the Archimedes method, and the relative density was calculated to be 96.1%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then attached to a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva) and subjected to sputtering.
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). At this time, the number of particles was 130.

(Comparative Example 1)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. As the C powder, carbon black having a fluorine content of 1 wtppm and a median diameter (D50) of 0.05 μm was used. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-30Pt-40C

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot press conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 1400 ° C., and a holding time of 2 hours, and pressurization was performed at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a temperature increase rate of 300 ° C./hour, a holding temperature of 1100 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of the temperature increase to 1100 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by the Archimedes method, and the relative density was calculated to be 94.8%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then attached to a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva) and subjected to sputtering.
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 4530.

(Comparative Example 2)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. As the C powder, graphite having a fluorine content of 5 wtppm and a median diameter (D50) of 6.3 μm was used. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-30Pt-40C

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot press conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 1400 ° C., and a holding time of 2 hours, and pressurization was performed at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a temperature increase rate of 300 ° C./hour, a holding temperature of 1100 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of the temperature increase to 1100 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by the Archimedes method, and the relative density was calculated to be 94.3%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then attached to a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva) and subjected to sputtering.
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 1121.

(Example 2)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. As the C powder, a material obtained by adding graphite fluoride (fluorine content ratio 40%) having an average particle diameter of 5 μm to a raw material of Comparative Example 3 described later until the fluorine content becomes 60 wtppm and mixing in a mortar. The median diameter (D50) of C powder was 19.8 μm. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-30Pt-40C

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot press conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 1400 ° C., and a holding time of 2 hours, and pressurization was performed at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a temperature increase rate of 300 ° C./hour, a holding temperature of 1100 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of the temperature increase to 1100 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by the Archimedes method, and the relative density was calculated to be 96.3%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then attached to a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva) and subjected to sputtering.
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 327.

(Comparative Example 3)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. As the C powder, graphite having a fluorine content of 5 wtppm and a median diameter (D50) of 20.2 μm was used. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-30Pt-40C

Next, both the weighed powders were put into a mortar with a capacity of 10 liters and rotated for 4 hours to mix. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot press conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 1400 ° C., and a holding time of 2 hours, and pressurization was performed at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a temperature increase rate of 300 ° C./hour, a holding temperature of 1100 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of the temperature increase to 1100 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by the Archimedes method, and the relative density was calculated to be 94.8%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then attached to a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva) and subjected to sputtering.
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 2,534.

(Example 3)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. As the C powder, a material obtained by adding graphite fluoride (fluorine content ratio 40%) having an average particle size of 10 μm to a raw material of Comparative Example 4 described later until the fluorine content becomes 200 wtppm and mixing in a mortar. Further, the median diameter (D50) of C powder was 13.4 μm. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-30Pt-40C

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then sputtering was performed on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva).
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 86 pieces.

(Comparative Example 4)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. As the C powder, graphite having a fluorine content of 5 wtppm and a median diameter (D50) of 13.9 μm was used. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-30Pt-40C

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot pressing conditions were a vacuum atmosphere, a temperature rising rate of 300 ° C./hour, a holding temperature of 1200 ° C., and a holding time of 2 hours, and pressurization was performed at 30 MPa from the start of temperature rising to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by Archimedes method, and the relative density was calculated to be 94.6%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then attached to a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva) and subjected to sputtering.
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 1062.

Example 4
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. As the C powder, natural graphite containing 40 wtppm of fluorine was used. Moreover, the median diameter (D50) of C powder was 0.11 micrometer. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-30Pt-40C

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then sputtering was performed on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva).
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 432 pieces.

(Comparative Example 5)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. As the C powder, a material obtained by firing the raw material of Example 4 in the atmosphere at 600 ° C. and subjecting it to defluorination treatment was used. This C powder had a fluorine content of less than 0.05 wtppm and a median diameter (D50) of 0.13 μm. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-30Pt-40C

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot press conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 1400 ° C., and a holding time of 2 hours, and pressurization was performed at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a temperature increase rate of 300 ° C./hour, a holding temperature of 1100 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of the temperature increase to 1100 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by the Archimedes method, and the relative density was calculated to be 94.2%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then attached to a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva) and subjected to sputtering.
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 3237.

(Example 5)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. As the C powder, a material obtained by adding graphite fluoride (fluorine content ratio 40%) having an average particle diameter of 5 μm to a raw material of Comparative Example 6 described later until the fluorine content becomes 15000 wtppm and mixing in a mortar was used. The median diameter (D50) of C powder was 5.6 μm. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-30Pt-40C

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot press conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 1400 ° C., and a holding time of 2 hours, and pressurization was performed at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a temperature increase rate of 300 ° C./hour, a holding temperature of 1100 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of the temperature increase to 1100 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by Archimedes method, and the relative density was calculated to be 96.0%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then sputtering was performed on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva).
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 78.

(Comparative Example 6)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. As the C powder, graphite having a fluorine content of 5 wtppm and a median diameter (D50) of 5.9 μm was used. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-30Pt-40C

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot press conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 1400 ° C., and a holding time of 2 hours, and pressurization was performed at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a temperature increase rate of 300 ° C./hour, a holding temperature of 1100 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of the temperature increase to 1100 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by Archimedes method, and the relative density was calculated to be 94.7%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then attached to a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva) and subjected to sputtering.
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 1680.

(Example 6)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, Ag powder having an average particle diameter of 5 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. For the C powder, natural graphite containing 150 wtppm of fluorine was used. Further, the median diameter (D50) of the C powder was 6.1 μm. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-25Pt-5Ag-40C

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot press conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 950 ° C., and a holding time of 2 hours, and pressure was applied at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a heating rate of 300 ° C./hour, a holding temperature of 950 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of heating to 950 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by Archimedes method, and the relative density was calculated to be 97.2%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then sputtering was performed on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva).
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 45.

(Comparative Example 7)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, Ag powder having an average particle diameter of 5 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. As the C powder, a material obtained by firing the raw material of Example 6 at 600 ° C. in the atmosphere and subjecting it to defluorination treatment was used. This C powder had a fluorine content of less than 0.05 wtppm and a median diameter (D50) of 6.1 μm. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-25Pt-5Ag-40C

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot press conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 950 ° C., and a holding time of 2 hours, and pressure was applied at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a heating rate of 300 ° C./hour, a holding temperature of 950 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of heating to 950 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by the Archimedes method, and the relative density was calculated to be 96.1%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then attached to a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva) and subjected to sputtering.
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 289.

(Example 7)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, C powder having an average particle diameter of 1 μm, and SiO ₂ powder having an average particle diameter of 1 μm were prepared as raw material powders. For the C powder, natural graphite containing 150 wtppm of fluorine was used. Further, the median diameter (D50) of the C powder was 6.1 μm. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-36Pt-15C-8SiO ₂

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot press conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 1090 ° C., and a holding time of 2 hours, and pressurization was performed at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a temperature increase rate of 300 ° C./hour, a holding temperature of 1100 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of the temperature increase to 1100 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by the Archimedes method and the relative density was calculated to be 98.8%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then sputtering was performed on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva).
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 22.

(Comparative Example 8)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, C powder having an average particle diameter of 1 μm, and SiO ₂ powder having an average particle diameter of 1 μm were prepared as raw material powders. As the C powder, a material obtained by firing the raw material of Example 7 at 600 ° C. in the air and subjecting it to defluorination treatment was used. This C powder had a fluorine content of less than 0.05 wtppm and a median diameter (D50) of 6.1 μm. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-36Pt-15C-8SiO ₂

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot press conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 1090 ° C., and a holding time of 2 hours, and pressurization was performed at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a temperature increase rate of 300 ° C./hour, a holding temperature of 1100 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of the temperature increase to 1100 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by the Archimedes method and the relative density was calculated to be 97.6%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then attached to a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva) and subjected to sputtering.
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 108.

(Example 8)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, Cu powder having an average particle diameter of 3.5 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. For the C powder, natural graphite containing 150 wtppm of fluorine was used. Further, the median diameter (D50) of the C powder was 6.1 μm. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-25Pt-5Cu-40C

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot pressing conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 1060 ° C., and a holding time of 2 hours, and pressurization was performed at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a heating rate of 300 ° C./hour, a holding temperature of 950 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of heating to 950 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by Archimedes method, and the relative density was calculated to be 97.1%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then sputtering was performed on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva).
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 28.

(Comparative Example 9)
Fe powder having an average particle diameter of 3 μm, Pt powder having an average particle diameter of 3 μm, Cu powder having an average particle diameter of 3.5 μm, and C powder having an average particle diameter of 1 μm were prepared as raw material powders. As the C powder, a material obtained by firing the raw material of Example 6 at 600 ° C. in the atmosphere and subjecting it to defluorination treatment was used. This C powder had a fluorine content of less than 0.05 wtppm and a median diameter (D50) of 6.1 μm. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-25Pt-5Cu-40C

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot pressing conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 1060 ° C., and a holding time of 2 hours, and pressurization was performed at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a heating rate of 300 ° C./hour, a holding temperature of 950 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of heating to 950 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by the Archimedes method, and the relative density was calculated to be 96.5%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then attached to a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva) and subjected to sputtering.
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 265.

Example 9
Fe powder having an average particle size of 3 μm, Pt powder having an average particle size of 3 μm, Ag powder having an average particle size of 5 μm, BN powder having an average particle size of 10 μm, and C powder having an average particle size of 1 μm were prepared as raw material powders. For the C powder, natural graphite containing 150 wtppm of fluorine was used. Further, the median diameter (D50) of the C powder was 6.1 μm. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-25Pt-5Ag-20BN-20C

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot press conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 950 ° C., and a holding time of 2 hours, and pressure was applied at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a heating rate of 300 ° C./hour, a holding temperature of 950 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of heating to 950 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by the Archimedes method and the relative density was calculated to be 97.3%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then sputtering was performed on a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva).
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 34.

(Comparative Example 10)
Fe powder having an average particle size of 3 μm, Pt powder having an average particle size of 3 μm, Ag powder having an average particle size of 5 μm, BN powder having an average particle size of 10 μm, and C powder having an average particle size of 1 μm were prepared as raw material powders. As the C powder, a material obtained by firing the raw material of Example 6 at 600 ° C. in the atmosphere and subjecting it to defluorination treatment was used. This C powder had a fluorine content of less than 0.05 wtppm and a median diameter (D50) of 6.1 μm. These powders were weighed in the following atomic ratio so that the total weight would be 2600 g.
Atomic ratio: Fe-25Pt-5Ag-20BN-20C

Next, the weighed powder was put into a mortar with a capacity of 10 liters and mixed by rotating for 4 hours. The mixed powder taken out from the mortar was filled into a carbon mold and hot pressed.
The hot press conditions were a vacuum atmosphere, a heating rate of 300 ° C./hour, a holding temperature of 950 ° C., and a holding time of 2 hours, and pressure was applied at 30 MPa from the start of heating to the end of holding. After completion of the holding, it was naturally cooled in the chamber.
Next, hot isostatic pressing was performed on the sintered body taken out from the hot press mold. The conditions for hot isostatic pressing were a heating rate of 300 ° C./hour, a holding temperature of 950 ° C., a holding time of 2 hours, and gradually increasing the Ar gas pressure from the start of heating to 950 ° During C holding, the pressure was increased to 150 MPa. After completion of the holding, it was naturally cooled in the furnace.
The sintered body thus produced had a fluorine content of less than 0.05 wtppm. The density was measured by the Archimedes method, and the relative density was calculated to be 96.3%.

Next, the sintered body was cut into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm with a lathe, and then attached to a magnetron sputtering apparatus (C-3010 sputtering system manufactured by Canon Anelva) and subjected to sputtering.
The sputtering conditions were an input power of 1 kW and an Ar gas pressure of 1.7 Pa. After performing 2 kWhr of pre-sputtering, a film was formed on a 4-inch diameter silicon substrate for 20 seconds. The number of particles having a diameter of 0.2 to 3.0 μm adhering to the substrate was measured with a surface foreign matter inspection apparatus (Surfscan 6420, manufactured by KLA-Tencor). The number at this time was 326.

Table 1 summarizes the above results. As shown in Table 1, in any case, the examples of the sputtering target of the present invention maintain the high density of the sputtering target, and the number of particles generated during sputtering is 500 or less, which is always less than that of the comparative example. Results were obtained.

The present invention makes it possible to form a granular magnetic thin film without using an expensive co-sputtering apparatus, and further, a high-density Fe-Pt system in which C particles are dispersed in which the amount of particles generated during sputtering is reduced. It has the outstanding effect which can provide a sputtering target. Therefore, it is useful as a sputtering target for forming a magnetic thin film having a granular structure.

Claims

Carbon powder used for manufacturing a sputtering target for forming a magnetic recording film, wherein the fluorine content is 50 wtppm or more.
2. The carbon powder according to claim 1, wherein the median diameter is 0.1 to 20 μm.
A sputtering target for forming a magnetic recording film, wherein the carbon powder according to claim 1 or 2 is used as a target raw material and is produced by a powder sintering method.
The sputtering target for forming a magnetic recording film according to claim 3, wherein the fluorine content is less than 0.05 wtppm.
After mixing the raw material powder containing the carbon powder according to claim 1 or 2, the mixed powder is molded and sintered, and the obtained sintered body is further subjected to isotropic hot pressing, and then the target shape. A method for producing a sputtering target for forming a magnetic recording film, characterized by: