Fe-Pt-based sputtering target with dispersed C grains

Abstract

A sintered compact sputtering target in which a composition ratio based on atomicity is represented by a formula of (Fe.sub.100-xPt.sub.x).sub.100-AC.sub.A (provided A is a number which satisfies 20A50 and X is a number which satisfies 35X55), wherein C grains are finely dispersed in an alloy, and the relative density is 90% or higher. The production of a magnetic thin film with granular structure is provided without using an expensive simultaneous sputtering device, and a high-density sputtering target capable of reducing the amount of particles generated during sputtering is provided.

Claims

1. A sputtering target, comprising a sintered compact having a composition expressed by a formula of (Fe.sub.100-xPt.sub.x).sub.100-AC.sub.A where A and X are numerals in units of atomic percent satisfying respectively 20A50 and 35X55, wherein C grains are finely dispersed within a FePt matrix alloy of the sintered compact, the C grains in a polished surface of the sputtering target have a mean area of 4 m.sup.2 or less, and the sintered compact has an oxygen content of 600 wtppm or less and a relative density of 90% or higher.

2. The sputtering target according to claim 1, wherein the C grains are made of graphite.

3. The sputtering target according to claim 2, wherein the sintered compact contains an oxide of one or more elements selected from the group consisting of B, Mg, Al, Si, Ti, Cr, Zr, Nb, and Ta in an amount of 20 mol % or less that is finely dispersed in the FePt matrix alloy of the sintered compact.

4. The sputtering target according to claim 1, wherein the sintered compact contains an oxide of one or more elements selected from the group consisting of B, Mg, Al, Si, Ti, Cr, Zr, Nb, and Ta in an amount of 20 mol % or less that is finely dispersed in the FePt matrix alloy of the sintered compact.

5. A sputtering target, comprising a sintered compact having a composition expressed by a formula of (Fe.sub.100-xPt.sub.x).sub.100-AC.sub.A where A, X, and Y are numerals in units of atomic percent satisfying respectively 20A50, 35X55, and 0.5Y15, wherein C grains are finely dispersed within a FePtCu matrix alloy of the sintered compact, the C grains in a polished surface of the sputtering target have a mean area of 4 m.sup.2 or less, and the sintered compact has an oxygen content of 600 wtppm or less and a relative density of 90% or higher.

6. The sputtering target according to claim 5, wherein the C grains are made of graphite.

7. The sputtering target according to claim 6, wherein the sintered compact contains an oxide of one or more elements selected from the group consisting of B, Mg, Al, Si, Ti, Cr, Zr, Nb, and Ta in an amount of 20 mol % or less that is finely dispersed in the FePtCu matrix alloy of the sintered compact.

8. The sputtering target according to claim 5, wherein the sintered compact contains an oxide of one or more elements selected from the group consisting of B, Mg, Al, Si, Ti, Cr, Zr, Nb, and Ta in an amount of 20 mol % or less that is finely dispersed in the FePtCu matrix alloy of the sintered compact.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 This is a structural image upon observing the polished surface of the sputtering target of Example 3 under an optical microscope.

DETAILED DESCRIPTION

(2) The FePt-based sputtering target with dispersed C grains of the present invention has a composition ratio based on atomicity that is represented by a formula of (Fe.sub.100-XPt.sub.X).sub.100-AC.sub.A (provided A is a number which satisfies 20A50 and X is a number which satisfies 35X55), C grains are finely and uniformly dispersed in a ferromagnetic matrix alloy, and the relative density is 90% or higher. This is the basic configuration of the present invention.

(3) In the present invention, the content of C grains is preferably an atomic ratio of 20 or more and 50 or less in the sputtering target composition. When the content of C grains in the target composition is less than an atomic ratio of 20, there are cases where favorable magnetic property cannot be obtained. On the other hand, when the content of C grains exceeds an atomic ratio of 50, the C grains become agglomerated to increase the generation of particles.

(4) Moreover, in the present invention, the content of Pt is preferably an atomic ratio of 35 or more and 55 or less in the FePt alloy composition. When the content of Pt in the FePt alloy is less than an atomic ratio of 35, there are cases where favorable magnetic property cannot be obtained. On the other hand, when the content of Pt exceeds an atomic ratio of 55, there are also cases where favorable magnetic property cannot be obtained.

(5) The relative density being 90% or higher is an important factor of the present invention. When the relative density is high, there will hardly be any problem caused by the degassing from the sputtering target during the sputtering process and, since the adhesion between the alloy and the C grains will increase, the generation of particles can be effectively inhibited. Desirably, the relative density is 95% or higher.

(6) In the present invention, the term relative density is a value obtained by dividing the measured density of the target by the calculated density (also known as the theoretical density). The term calculated density is a density that is obtained on the assumption that the constituents of the target coexist without mutually diffusing or reacting, and is calculated according to the following formula.
Calculated density=(molecular weight of constituentsmolar ratio of constituents)/(molecular weight of constituentsmolar ratio of constituents/literature density of constituents)Formula:

(7) Here, means to acquire the sum regarding all constituents of the target.

(8) Moreover, with the sputtering target of the present invention, the ferromagnetic FePtCu alloy can be used as the matrix alloy. In other words, the sputtering target of the present invention has a composition ratio based on atomicity that is represented by a formula of (Fe.sub.100-X-YPt.sub.XCu.sub.Y).sub.100-AC.sub.A (provided that A is a number which satisfies 20A50, X is a number which satisfies 35X55, and Y is a number which satisfies 0.5Y15), C grains are finely and uniformly dispersed in the matrix alloy, and the relative density is 90% or higher.

(9) In the present invention, the content of Pt is preferably an atomic ratio of 35 or more and 55 or less in the FePtCu alloy composition. When the content of Pt in the FePtCu alloy is less than an atomic ratio of 35 or exceeds an atomic ratio of 55, there are cases where favorable magnetic property cannot be obtained.

(10) Moreover, the content of Cu is preferably an atomic ratio of 0.5 or more and 15 or less in the FePtCu alloy composition. When the content of Cu in the FePtCu alloy is less than an atomic ratio of 0.5, there are cases where the heat treatment temperature cannot be sufficiently lowered upon causing the deposited magnetic thin film with granular structure to have an L1.sub.0 structure. On the other hand, when the content of Cu exceeds an atomic ratio of 15, there are cases where favorable magnetic property cannot be obtained.

(11) Moreover, with the sputtering target of the present invention, it is particularly effective to disperse C grains having a mean area of 4 m.sup.2 or less in the alloy. When the mean area exceeds 4 m.sup.2, the produced sputtering target is unable to effectively inhibit the generation of particles during sputtering. Note that the mean area is derived as a value obtained by dividing an area of the C grains observed on the polished surface of the mill ends cut out from the sputtering target by the number of such C grains.

(12) Moreover, with the sputtering target of the present invention, C grains that are made of graphite are desirably used. This is because, when the C grains are graphitoid, the produced sputtering target can more effectively inhibit the generation of particles.

(13) Moreover, the sputtering target of the present invention is particularly effective when the oxygen concentration is 600 wtppm or less, more preferably 500 wtppm or less. This will result in the reduction of the oxygen content in the FePt magnetic grains in the magnetic thin film that is produced by sputtering the target of the present invention, and the produced magnetic thin film can thereby obtain favorable magnetic property.

(14) Moreover, the sputtering target of the present invention may contain, as an additive component, an oxide of one or more elements selected among B, Mg, Al, Si, Ti, Cr, Zr, Nb, and Ta in an amount of 20 mol % or less. In the magnetic thin film produced by sputtering the target of the present invention, the oxide, together with C, will take on a structure of insulating the magnetic interaction of the magnetic grains, and therefore, the produced magnetic thin film can have favorable magnetic property. Moreover, from the perspective of inhibiting the generation of particles during sputtering, desirably, the oxide is also finely dispersed in the alloy as with C. The lower limit of the additive amount preferably set to 1 mol %. This is because if the additive amount is less than this lower limit, there is no additive effect.

(15) The sputtering target of the present invention is produced via the powder sintering method. For this production, respective raw material powders (Fe powder, Pt powder, Cu powder, C powder, oxide powder) are prepared. These powders desirably have a grain size of 0.5 m or more and 10 m or less. When the grain size of the raw material powder is too small, there is a problem in that the raw material powders tend to become agglomerated and, therefore, the grain size is desirably 0.5 m or more. Meanwhile, when the grain size of the raw material powder is large, it becomes difficult to finely disperse the C grains in the alloy and, therefore, the grain size is desirably 10 m or less.

(16) In addition, as the raw material powder, alloy powders (FePt powder, FeCu powder, PtCu powder, FePtCu powder) may also be used. In particular, depending on the composition of the alloy powders containing Pt, alloy powders may be effective in reducing the amount of oxygen in the raw material powder. Even in cases of using alloy powders, the alloy powders desirably have a grain size of 0.5 m or more and 10 m or less.

(17) In addition, the foregoing powders are weighed to achieve the intended composition, and pulverized and mixed by using a publicly known method such as a ball mill.

(18) The mixed powder obtained thereby is molded and sintered via hot press. In addition to hot press, methods such as the plasma discharge sintering method and hot isostatic sintering method may also be used. The holding temperature during sintering will depend on the composition of the sputtering target, but in many cases the holding temperature is within the temperature range of 1200 to 1400 C.

(19) Subsequently, hot isostatic pressing is performed to the sintered compact obtained from the hot press. Hot isostatic pressing is effective for improving the density of the sintered compact. The holding temperature during hot isostatic pressing will depend on the composition of the sintered compact, but in many cases the holding temperature is within the temperature range of 1200 to 1400 C. Moreover, the pressure is set to 100 Mpa or more.

(20) The sintered compact obtained thereby is processed into an intended shape with a lathe in order to produce the sputtering target of the present invention.

(21) Accordingly, it is possible to produce a high-density FePt-based sputtering target with dispersed C grains, in which C grains are finely and uniformly dispersed in the alloy. The sputtering target of the present invention produced as described above is effective as a sputtering target that is used for the deposition of a magnetic thin film with granular structure.

EXAMPLES

(22) The present invention is now explained based on Examples and Comparative Examples. Note that these Examples are merely an example, and the present invention is not in any way limited to these Examples. In other words, the present invention is limited only by the patent claims, and covers various modifications other than the Examples included in the present invention.

Example 1

(23) As the raw material powders, Fe powder having an average grain size of 3 m, Pt powder having an average grain size of 3 m, and C powder having an average grain size of 1 m were prepared. As the C powder, commercially available amorphous carbon was used.

(24) These powders were weighed to achieve a total weight of 2600 g based on the following atomic ratio.

(25) Atomic ratio: (Fe.sub.50Pt.sub.50).sub.60C.sub.40

(26) Subsequently, the weighed powders were placed in a ball mill pot with a capacity of 10 liters together with zirconia balls as the grinding medium, and the mill pot was rotated for 4 hours for mixing and pulverizing. The mixed powder that was removed from the ball mill was filled in a carbon mold and hot pressed.

(27) The hot press conditions were as follows; namely, vacuum atmosphere, rate of temperature increase of 300 C./hour, holding temperature of 1200 C., and holding time of 2 hours, and pressure of 30 MPa was applied from the start of temperature increase to the end of holding. After the end of holding, the product was naturally cooled as is in a chamber.

(28) Subsequently, hot isostatic pressing was performed to the sintered compact that was removed from the hot press mold. The hot isostatic pressing conditions were as follows; namely, rate of temperature increase of 300 C./hour, holding temperature of 1350 C., and holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and pressure of 150 MPa was applied during the holding at 1350 C. After the end of holding, the product was naturally cooled in the furnace.

(29) The density of the sintered compact prepared as described above was measured with the Archimedian method, and the relative density was calculated. The result was 96.6%.

(30) Subsequently, the end part of the obtained sintered compact was cut out, and the cross-section surface was polished to observe the structure thereof with an optical microscope. A structural image having a visual field size of 108 m80 m was captured at four locations that were arbitrarily selected on the structure surface. The captured image was binarized using image-editing software to obtain the number and area of the portion (blackish portion in the structural observation image) corresponding to the C grains. As a result of calculating the mean area per one C grain, the result was 2.9 m.sup.2. Moreover, as a result of measuring the oxygen content in the sintered compact by using mill ends, the result was 560 wtppm.

(31) Subsequently, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and thereafter mounted on a magnetron sputtering device (C-3010 sputtering system manufactured by Canon Anelva) to perform sputtering.

(32) The sputtering conditions were input power of 1 kW and Ar gas pressure of 1.7 Pa, and, after performing pre-sputtering of 2 kWhr, deposition was performed onto a silicon substrate having a 4-inch diameter for 20 seconds.

(33) The number of particles that adhered on the substrate was measured with a particle counter. The result was 410 particles.

Comparative Example 1

(34) As the raw material powders, Fe powder having an average grain size of 3 m, Pt powder having an average grain size of 3 m, and C powder having an average grain size of 1 m were prepared. As the C powder, commercially available amorphous carbon was used.

(35) These powders were weighed to achieve a total weight of 2600 g based on the following atomic ratio.

(36) Atomic ratio: (Fe.sub.50Pt.sub.50).sub.60C.sub.40

(37) Subsequently, the weighed powders were placed in a ball mill pot with a capacity of 10 liters together with zirconia balls as the grinding medium, and the mill pot was rotated for 4 hours for mixing and pulverizing. The mixed powder that was removed from the ball mill was filled in a carbon mold and hot pressed.

(38) The hot press conditions were as follows; namely, vacuum atmosphere, rate of temperature increase of 300 C./hour, holding temperature of 1200 C., and holding time of 2 hours, and pressure of 30 MPa was applied from the start of temperature increase to the end of holding. After the end of holding, the product was naturally cooled as is in a chamber.

(39) The density of the sintered compact prepared as described above was measured with the Archimedian method, and the relative density was calculated. The result was 83.6%.

(40) Subsequently, the end part of the obtained sintered compact was cut out, and the cross-section surface was polished to observe the structure thereof with an optical microscope. A structural image having a visual field size of 108 m80 m was captured at four locations that were arbitrarily selected on the structure surface. The captured image was binarized using image-editing software to obtain the number and area of the portion (blackish portion in the structural observation image) corresponding to the C grains. As a result of calculating the mean area per one C grain, the result was 2.7 m.sup.2. Moreover, as a result of measuring the oxygen content in the sintered compact by using mill ends, the result was 620 wtppm.

(41) Subsequently, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and thereafter mounted on a magnetron sputtering device (C-3010 sputtering system manufactured by Canon Anelva) to perform sputtering.

(42) The sputtering conditions were input power of 1 kW and Ar gas pressure of 1.7 Pa, and, after performing pre-sputtering of 2 kWhr, deposition was performed onto a silicon substrate having a 4-inch diameter for 20 seconds. The number of particles that adhered on the substrate was measured with a particle counter. The result was 9640 particles.

Comparative Example 2

(43) As the raw material powders, Fe powder having an average grain size of 3 m, Pt powder having an average grain size of 3 m, and C powder having an average grain size of 1 m were prepared. As the C powder, commercially available amorphous carbon was used.

(44) These powders were weighed to achieve a total weight of 2050 g based on the following atomic ratio.

(45) Atomic ratio: (Fe.sub.50Pt.sub.50).sub.40C.sub.60

(46) Subsequently, the weighed powders were placed in a ball mill pot with a capacity of 10 liters together with zirconia balls as the grinding medium, and the mill pot was rotated for 4 hours for mixing and pulverizing. The mixed powder that was removed from the ball mill was filled in a carbon mold and hot pressed.

(47) The hot press conditions were as follows; namely, vacuum atmosphere, rate of temperature increase of 300 C./hour, holding temperature of 1200 C., and holding time of 2 hours, and pressure of 30 MPa was applied from the start of temperature increase to the end of holding. After the end of holding, the product was naturally cooled as is in a chamber.

(48) Subsequently, hot isostatic pressing was performed to the sintered compact that was removed from the hot press mold. The hot isostatic pressing conditions were as follows; namely, rate of temperature increase of 300 C./hour, holding temperature of 1350 C., and holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and pressure of 150 MPa was applied during the holding at 1350 C. After the end of holding, the product was naturally cooled in the furnace.

(49) The density of the sintered compact prepared as described above was measured with the Archimedian method, and the relative density was calculated. The result was 87.8%.

(50) Subsequently, the end part of the obtained sintered compact was cut out, and the cross-section surface was polished to observe the structure thereof with an optical microscope. A structural image having a visual field size of 108 m80 m was captured at four locations that were arbitrarily selected on the structure surface. The captured image was binarized using image-editing software to obtain the number and area of the portion (blackish portion in the structural observation image) corresponding to the C grains. As a result of calculating the mean area per one C grain, the result was 6.2 m.sup.2. Moreover, as a result of measuring the oxygen content in the sintered compact by using mill ends, the result was 820 wtppm.

(51) Subsequently, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and thereafter mounted on a magnetron sputtering device (C-3010 sputtering system manufactured by Canon Anelva) to perform sputtering.

(52) The sputtering conditions were input power of 1 kW and Ar gas pressure of 1.7 Pa, and, after performing pre-sputtering of 2 kWhr, deposition was performed onto a silicon substrate having a 4-inch diameter for 20 seconds. The number of particles that adhered on the substrate was measured with a particle counter. The result was 20000 particles or more.

Example 2

(53) As the raw material powders, Fe powder having an average grain size of 3 m, Pt powder having an average grain size of 3 m, Cu powder having an average grain size of 3 m, and C powder having an average grain size of 1 m were prepared. As the C powder, commercially available amorphous carbon was used.

(54) These powders were weighed to achieve a total weight of 2380 g based on the following atomic ratio.

(55) Atomic ratio: (Fe.sub.40Pt.sub.45Cu.sub.15).sub.55C.sub.45

(56) Subsequently, the weighed powders were placed in a ball mill pot with a capacity of 10 liters together with zirconia balls as the grinding medium, and the mill pot was rotated for 4 hours for mixing and pulverizing. The mixed powder that was removed from the ball mill was filled in a carbon mold and hot pressed.

(57) The hot press conditions were as follows; namely, vacuum atmosphere, rate of temperature increase of 300 C./hour, holding temperature of 1200 C., and holding time of 2 hours, and pressure of 30 MPa was applied from the start of temperature increase to the end of holding. After the end of holding, the product was naturally cooled as is in a chamber.

(58) Subsequently, hot isostatic pressing was performed to the sintered compact that was removed from the hot press mold. The hot isostatic pressing conditions were as follows; namely, rate of temperature increase of 300 C./hour, holding temperature of 1350 C., and holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and pressure of 150 MPa was applied during the holding at 1350 C. After the end of holding, the product was naturally cooled in the furnace.

(59) The density of the sintered compact prepared as described above was measured with the Archimedian method, and the relative density was calculated. The result was 95.8%.

(60) Subsequently, the end part of the obtained sintered compact was cut out, and the cross-section surface was polished to observe the structure thereof with an optical microscope. A structural image having a visual field size of 108 m80 m was captured at four locations that were arbitrarily selected on the structure surface. The captured image was binarized using image-editing software to obtain the number and area of the portion (blackish portion in the structural observation image) corresponding to the C grains. As a result of calculating the mean area per one C grain, the result was 2.7 m.sup.2. Moreover, as a result of measuring the oxygen content in the sintered compact by using mill ends, the result was 540 wtppm.

(61) Subsequently, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and thereafter mounted on a magnetron sputtering device (C-3010 sputtering system manufactured by Canon Anelva) to perform sputtering.

(62) The sputtering conditions were input power of 1 kW and Ar gas pressure of 1.7 Pa, and, after performing pre-sputtering of 2 kWhr, deposition was performed onto a silicon substrate having a 4-inch diameter for 20 seconds. The number of particles that adhered on the substrate was measured with a particle counter. The result was 320 particles.

Comparative Example 3

(63) As the raw material powders, Fe powder having an average grain size of 3 m, Pt powder having an average grain size of 3 m, Cu powder having an average grain size of 3 m, and C powder having an average grain size of 1 m were prepared. As the C powder, commercially available amorphous carbon was used.

(64) These powders were weighed to achieve a total weight of 2380 g based on the following atomic ratio.

(65) Atomic ratio: (Fe.sub.40Pt.sub.45Cu.sub.15).sub.55C.sub.45

(66) Subsequently, the weighed powders were placed in a ball mill pot with a capacity of 10 liters together with zirconia balls as the grinding medium, and the mill pot was rotated for 4 hours for mixing and pulverizing. The mixed powder that was removed from the ball mill was filled in a carbon mold and hot pressed.

(67) The hot press conditions were as follows; namely, vacuum atmosphere, rate of temperature increase of 300 C./hour, holding temperature of 1200 C., and holding time of 2 hours, and pressure of 30 MPa was applied from the start of temperature increase to the end of holding. After the end of holding, the product was naturally cooled as is in a chamber.

(68) The density of the sintered compact prepared as described above was measured with the Archimedian method, and the relative density was calculated. The result was 85.7%.

(69) Subsequently, the end part of the obtained sintered compact was cut out, and the cross-section surface was polished to observe the structure thereof with an optical microscope. A structural image having a visual field size of 108 m80 m was captured at four locations that were arbitrarily selected on the structure surface. The captured image was binarized using image-editing software to obtain the number and area of the portion (blackish portion in the structural observation image) corresponding to the C grains. As a result of calculating the mean area per one C grain, the result was 2.5 m.sup.2. Moreover, as a result of measuring the oxygen content in the sintered compact by using mill ends, the result was 580 wtppm.

(70) Subsequently, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and thereafter mounted on a magnetron sputtering device (C-3010 sputtering system manufactured by Canon Anelva) to perform sputtering.

(71) The sputtering conditions were input power of 1 kW and Ar gas pressure of 1.7 Pa, and, after performing pre-sputtering of 2 kWhr, deposition was performed onto a silicon substrate having a 4-inch diameter for 20 seconds. The number of particles that adhered on the substrate was measured with a particle counter. The result was 11210 particles.

Example 3

(72) As the raw material powders, Fe powder having an average grain size of 3 m, Pt powder having an average grain size of 3 m, and C powder having an average grain size of 1 m were prepared. As the C powder, commercially available amorphous carbon was used.

(73) These powders were weighed to achieve a total weight of 2600 g based on the following atomic ratio.

(74) Atomic ratio: (Fe.sub.50Pt.sub.50).sub.60C.sub.40

(75) Subsequently, the weighed powders were placed in a ball mill pot with a capacity of 10 liters together with zirconia balls as the grinding medium, and the mill pot was rotated for 16 hours for mixing and pulverizing. The mixed powder that was removed from the ball mill was filled in a carbon mold and hot pressed.

(76) The hot press conditions were as follows; namely, vacuum atmosphere, rate of temperature increase of 300 C./hour, holding temperature of 1200 C., and holding time of 2 hours, and pressure of 30 MPa was applied from the start of temperature increase to the end of holding. After the end of holding, the product was naturally cooled as is in a chamber.

(77) Subsequently, hot isostatic pressing was performed to the sintered compact that was removed from the hot press mold. The hot isostatic pressing conditions were as follows; namely, rate of temperature increase of 300 C./hour, holding temperature of 1350 C., and holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and pressure of 150 MPa was applied during the holding at 1350 C. After the end of holding, the product was naturally cooled in the furnace.

(78) The density of the sintered compact prepared as described above was measured with the Archimedian method, and the relative density was calculated. The result was 96.9%.

(79) Subsequently, the end part of the obtained sintered compact was cut out, and the cross-section surface was polished to observe the structure thereof with an optical microscope. A structural image having a visual field size of 108 m80 m was captured at four locations that were arbitrarily selected on the structure surface. The captured image was binarized using image-editing software to obtain the number and area of the portion (blackish portion in the structural observation image) corresponding to the C grains. As a result of calculating the mean area per one C grain, the result was 1.0 m.sup.2. Moreover, as a result of measuring the oxygen content in the sintered compact by using mill ends, the result was 870 wtppm.

(80) FIG. 1 shows a microscopic photo of the cross section surface. As shown in FIG. 1, it can be seen that the C grains (black portion) are uniformly dispersed in the alloy (white portion).

(81) Subsequently, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and thereafter mounted on a magnetron sputtering device (C-3010 sputtering system manufactured by Canon Anelva) to perform sputtering.

(82) The sputtering conditions were input power of 1 kW and Ar gas pressure of 1.7 Pa, and, after performing pre-sputtering of 2 kWhr, deposition was performed onto a silicon substrate having a 4-inch diameter for 20 seconds. The number of particles that adhered on the substrate was measured with a particle counter. The result was 230 particles.

Example 4

(83) As the raw material powders, Fe powder having an average grain size of 3 m, Pt powder having an average grain size of 3 m, and C powder having an average grain size of 5 m were prepared. As the C powder, graphite powder having a true specific gravity of 2.25 g/cc was used.

(84) These powders were weighed to achieve a total weight of 2600 g based on the following atomic ratio.

(85) Atomic ratio: (Fe.sub.50Pt.sub.50).sub.60C.sub.40

(86) Subsequently, the weighed powders were placed in a ball mill pot with a capacity of 10 liters together with zirconia balls as the grinding medium, and the mill pot was rotated for 4 hours for mixing and pulverizing. The mixed powder that was removed from the ball mill was filled in a carbon mold and hot pressed.

(87) The hot press conditions were as follows; namely, vacuum atmosphere, rate of temperature increase of 300 C./hour, holding temperature of 1200 C., and holding time of 2 hours, and pressure of 30 MPa was applied from the start of temperature increase to the end of holding. After the end of holding, the product was naturally cooled as is in a chamber.

(88) Subsequently, hot isostatic pressing was performed to the sintered compact that was removed from the hot press mold. The hot isostatic pressing conditions were as follows; namely, rate of temperature increase of 300 C./hour, holding temperature of 1350 C., and holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and pressure of 150 MPa was applied during the holding at 1350 C. After the end of holding, the product was naturally cooled in the furnace.

(89) The density of the sintered compact prepared as described above was measured with the Archimedian method, and the relative density was calculated. The result was 97.6%.

(90) Subsequently, the end part of the obtained sintered compact was cut out, and the cross-section surface was polished to observe the structure thereof with an optical microscope. A structural image having a visual field size of 108 m80 m was captured at four locations that were arbitrarily selected on the structure surface. The captured image was binarized using image-editing software to obtain the number and area of the portion (blackish portion in the structural observation image) corresponding to the C grains. As a result of calculating the mean area per one C grain, the result was 3.2 m.sup.2. Moreover, as a result of measuring the oxygen content in the sintered compact by using mill ends, the result was 600 wtppm.

(91) Subsequently, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and thereafter mounted on a magnetron sputtering device (C-3010 sputtering system manufactured by Canon Anelva) to perform sputtering.

(92) The sputtering conditions were input power of 1 kW and Ar gas pressure of 1.7 Pa, and, after performing pre-sputtering of 2 kWhr, deposition was performed onto a silicon substrate having a 4-inch diameter for 20 seconds. The number of particles that adhered on the substrate was measured with a particle counter. The result was 170 particles.

Example 5

(93) As the raw material powders, FePt alloy powder having an average grain size of 10 m, and C powder having an average grain size of 1 m were prepared. As the C powder, commercially available amorphous carbon was used.

(94) These powders were weighed to achieve a total weight of 2600 g based on the following atomic ratio.

(95) Atomic ratio: (Fe.sub.50Pt.sub.50).sub.60C.sub.40

(96) Subsequently, the weighed powders were placed in a ball mill pot with a capacity of 10 liters together with zirconia balls as the grinding medium, and the mill pot was rotated for 8 hours for mixing and pulverizing. The mixed powder that was removed from the ball mill was filled in a carbon mold and hot pressed.

(97) The hot press conditions were as follows; namely, vacuum atmosphere, rate of temperature increase of 300 C./hour, holding temperature of 1200 C., and holding time of 2 hours, and pressure of 30 MPa was applied from the start of temperature increase to the end of holding. After the end of holding, the product was naturally cooled as is in a chamber.

(98) Subsequently, hot isostatic pressing was performed to the sintered compact that was removed from the hot press mold. The hot isostatic pressing conditions were as follows; namely, rate of temperature increase of 300 C./hour, holding temperature of 1350 C., and holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and pressure of 150 MPa was applied during the holding at 1350 C. After the end of holding, the product was naturally cooled in the furnace.

(99) The density of the sintered compact prepared as described above was measured with the Archimedian method, and the relative density was calculated. The result was 97.1%.

(100) Subsequently, the end part of the obtained sintered compact was cut out, and the cross-section surface was polished to observe the structure thereof with an optical microscope. A structural image having a visual field size of 108 m80 m was captured at four locations that were arbitrarily selected on the structure surface. The captured image was binarized using image-editing software to obtain the number and area of the portion (blackish portion in the structural observation image) corresponding to the C grains. As a result of calculating the mean area per one C grain, the result was 2.6 m.sup.2. Moreover, as a result of measuring the oxygen content in the sintered compact by using mill ends, the result was 280 wtppm.

(101) Subsequently, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and thereafter mounted on a magnetron sputtering device (C-3010 sputtering system manufactured by Canon Anelva) to perform sputtering.

(102) The sputtering conditions were input power of 1 kW and Ar gas pressure of 1.7 Pa, and, after performing pre-sputtering of 2 kWhr, deposition was performed onto a silicon substrate having a 4-inch diameter for 20 seconds.

(103) The number of particles that adhered on the substrate was measured with a particle counter. The result was 360 particles.

Example 6

(104) As the raw material powders, Fe powder having an average grain size of 3 m, Pt powder having an average grain size of 3 m, C powder having an average grain size of 1 m, and SiO.sub.2 powder having an average grain size of 1 m were prepared. As the C powder, graphite powder having a true specific gravity of 2.25 g/cc was used.

(105) These powders were weighed to achieve a total weight of 2600 g based on the following atomic ratio.

(106) Atomic ratio: (Fe.sub.50Pt.sub.50).sub.69C.sub.10Si.sub.7O.sub.14

(107) Subsequently, the weighed powders were placed in a ball mill pot with a capacity of 10 liters together with zirconia balls as the grinding medium, and the mill pot was rotated for 4 hours for mixing and pulverizing. The mixed powder that was removed from the ball mill was filled in a carbon mold and hot pressed.

(108) The hot press conditions were as follows; namely, vacuum atmosphere, rate of temperature increase of 300 C./hour, holding temperature of 1200 C., and holding time of 2 hours, and pressure of 30 MPa was applied from the start of temperature increase to the end of holding. After the end of holding, the product was naturally cooled as is in a chamber.

(109) Subsequently, hot isostatic pressing was performed to the sintered compact that was removed from the hot press mold. The hot isostatic pressing conditions were as follows; namely, rate of temperature increase of 300 C./hour, holding temperature of 1200 C., and holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and pressure of 150 MPa was applied during the holding at 1200 C. After the end of holding, the product was naturally cooled in the furnace.

(110) The density of the sintered compact prepared as described above was measured with the Archimedian method, and the relative density was calculated. The result was 98.6%.

(111) Subsequently, the end part of the obtained sintered compact was cut out, and the cross-section surface was polished to observe the structure thereof with an electron-beam microanalyzer. An element distribution of the polished surface having a visual field size of 80 m80 m was captured at four locations that were arbitrarily selected on the structure surface. The captured element distribution image of C was binarized using image-editing software to obtain the number and area of the portion corresponding to the C grains. As a result of calculating the mean area per one C grain, the result was 2.5 m.sup.2.

(112) Subsequently, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and thereafter mounted on a magnetron sputtering device (C-3010 sputtering system manufactured by Canon Anelva) to perform sputtering.

(113) The sputtering conditions were input power of 1 kW and Ar gas pressure of 1.7 Pa, and, after performing pre-sputtering of 2 kWhr, deposition was performed onto a silicon substrate having a 4-inch diameter for 20 seconds. The number of particles that adhered on the substrate was measured with a particle counter. The result was 120 particles.

Comparative Example 4

(114) As the raw material powders, Fe powder having an average grain size of 3 m, Pt powder having an average grain size of 3 m, C powder having an average grain size of 20 m, and SiO.sub.2 powder having an average grain size of 1 m were prepared. As the C powder, graphite powder having a true specific gravity of 2.25 g/cc was used.

(115) These powders were weighed to achieve a total weight of 2600 g based on the following atomic ratio.

(116) Atomic ratio: (Fe.sub.50Pt.sub.50).sub.69C.sub.10Si.sub.7O.sub.14

(117) Subsequently, the weighed powders were placed in a ball mill pot with a capacity of 10 liters together with zirconia balls as the grinding medium, and the mill pot was rotated for 4 hours for mixing and pulverizing. The mixed powder that was removed from the ball mill was filled in a carbon mold and hot pressed.

(118) The hot press conditions were as follows; namely, vacuum atmosphere, rate of temperature increase of 300 C./hour, holding temperature of 1200 C., and holding time of 2 hours, and pressure of 30 MPa was applied from the start of temperature increase to the end of holding. After the end of holding, the product was naturally cooled as is in a chamber.

(119) Subsequently, hot isostatic pressing was performed to the sintered compact that was removed from the hot press mold. The hot isostatic pressing conditions were as follows; namely, rate of temperature increase of 300 C./hour, holding temperature of 1200 C., and holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and pressure of 150 MPa was applied during the holding at 1200 C. After the end of holding, the product was naturally cooled in the furnace.

(120) The density of the sintered compact prepared as described above was measured with the Archimedian method, and the relative density was calculated. The result was 98.1%.

(121) Subsequently, the end part of the obtained sintered compact was cut out, and the cross-section surface was polished to observe the structure thereof with an electron-beam microanalyzer. An element distribution of the polished surface having a visual field size of 80 m80 m was captured at four locations that were arbitrarily selected on the structure surface. The captured element distribution image of C was binarized using image-editing software to obtain the number and area of the portion corresponding to the C grains. As a result of calculating the mean area per one C grain, the result was 11.5 m.sup.2.

(122) Subsequently, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and thereafter mounted on a magnetron sputtering device (C-3010 sputtering system manufactured by Canon Anelva) to perform sputtering.

(123) The sputtering conditions were input power of 1 kW and Ar gas pressure of 1.7 Pa, and, after performing pre-sputtering of 2 kWhr, deposition was performed onto a silicon substrate having a 4-inch diameter for 20 seconds. The number of particles that adhered on the substrate was measured with a particle counter. The result was 510 particles.

Example 7

(124) As the raw material powders, Fe powder having an average grain size of 3 m, Pt powder having an average grain size of 3 m, Cu power having an average grain size of 3 m, C powder having an average grain size of 1 m, and MgO powder having an average grain size of 2 m were prepared. As the C powder, graphite powder having a true specific gravity of 2.25 g/cc was used.

(125) These powders were weighed to achieve a total weight of 2500 g based on the following atomic ratio.

(126) Atomic ratio: (Fe.sub.45Pt.sub.45Cu.sub.10).sub.64C.sub.18Mg.sub.9O.sub.9

(127) Subsequently, the weighed powders were placed in a ball mill pot with a capacity of 10 liters together with zirconia balls as the grinding medium, and the mill pot was rotated for 4 hours for mixing and pulverizing. The mixed powder that was removed from the ball mill was filled in a carbon mold and hot pressed.

(128) The hot press conditions were as follows; namely, vacuum atmosphere, rate of temperature increase of 300 C./hour, holding temperature of 1250 C., and holding time of 2 hours, and pressure of 30 MPa was applied from the start of temperature increase to the end of holding. After the end of holding, the product was naturally cooled as is in a chamber.

(129) Subsequently, hot isostatic pressing was performed to the sintered compact that was removed from the hot press mold. The hot isostatic pressing conditions were as follows; namely, rate of temperature increase of 300 C./hour, holding temperature of 1250 C., and holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and pressure of 150 MPa was applied during the holding at 1250 C. After the end of holding, the product was naturally cooled in the furnace.

(130) The density of the sintered compact prepared as described above was measured with the Archimedian method, and the relative density was calculated. The result was 98.2%.

(131) Subsequently, the end part of the obtained sintered compact was cut out, and the cross-section surface was polished to observe the structure thereof with an electron-beam microanalyzer. An element distribution of the polished surface having a visual field size of 80 m80 m was captured at four locations that were arbitrarily selected on the structure surface. The captured element distribution image of C was binarized using image-editing software to obtain the number and area of the portion corresponding to the C grains. As a result of calculating the mean area per one C grain, the result was 2.6 m.sup.2.

(132) Subsequently, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and thereafter mounted on a magnetron sputtering device (C-3010 sputtering system manufactured by Canon Anelva) to perform sputtering.

(133) The sputtering conditions were input power of 1 kW and Ar gas pressure of 1.7 Pa, and, after performing pre-sputtering of 2 kWhr, deposition was performed onto a silicon substrate having a 4-inch diameter for 20 seconds. The number of particles that adhered on the substrate was measured with a particle counter. The result was 320 particles.

Example 8

(134) As the raw material powders, Fe powder having an average grain size of 3 m, Pt powder having an average grain size of 3 m, C powder having an average grain size of 1 m, and Cr.sub.2O.sub.3 powder having an average grain size of 3 m were prepared. As the C powder, graphite powder having a true specific gravity of 2.25 g/cc was used.

(135) These powders were weighed to achieve a total weight of 2600 g based on the following atomic ratio.

(136) Atomic ratio: (Fe.sub.60Pt.sub.40).sub.62.5C.sub.16.67Cr.sub.8.33O.sub.12.50

(137) Subsequently, the weighed powders were placed in a ball mill pot with a capacity of 10 liters together with zirconia balls as the grinding medium, and the mill pot was rotated for 4 hours for mixing and pulverizing. The mixed powder that was removed from the ball mill was filled in a carbon mold and hot pressed.

(138) The hot press conditions were as follows; namely, vacuum atmosphere, rate of temperature increase of 300 C./hour, holding temperature of 1150 C., and holding time of 2 hours, and pressure of 30 MPa was applied from the start of temperature increase to the end of holding. After the end of holding, the product was naturally cooled as is in a chamber.

(139) Subsequently, hot isostatic pressing was performed to the sintered compact that was removed from the hot press mold. The hot isostatic pressing conditions were as follows; namely, rate of temperature increase of 300 C./hour, holding temperature of 1150 C., and holding time of 2 hours, and the Ar gas pressure was gradually increased from the start of temperature increase, and pressure of 150 MPa was applied during the holding at 1150 C. After the end of holding, the product was naturally cooled in the furnace.

(140) The density of the sintered compact prepared as described above was measured with the Archimedian method, and the relative density was calculated. The result was 96.7%.

(141) Subsequently, the end part of the obtained sintered compact was cut out, and the cross-section surface was polished to observe the structure thereof with an electron-beam microanalyzer. An element distribution of the polished surface having a visual field size of 80 m80 m was captured at four locations that were arbitrarily selected on the structure surface. The captured element distribution image of C was binarized using image-editing software to obtain the number and area of the portion corresponding to the C grains. As a result of calculating the mean area per one C grain, the result was 1.8 m.sup.2.

(142) Subsequently, the sintered compact was cut with a lathe into a shape having a diameter of 180.0 mm and a thickness of 5.0 mm, and thereafter mounted on a magnetron sputtering device (C-3010 sputtering system manufactured by Canon Anelva) to perform sputtering.

(143) The sputtering conditions were input power of 1 kW and Ar gas pressure of 1.7 Pa, and, after performing pre-sputtering of 2 kWhr, deposition was performed onto a silicon substrate having a 4-inch diameter for 20 seconds. The number of particles that adhered on the substrate was measured with a particle counter. The result was 260 particles.

(144) The foregoing results are summarized in Table 1. As shown in Table 1, all Examples of the sputtering target of the present invention maintained a high density of the sputtering target, and the number of particles generated during the sputtering was 500 particles or less, and was constantly fewer than the Comparative Examples.

(145) TABLE-US-00001 TABLE 1 Oxygen Relative density C grains concentration Number of No. Target composition (Atomic ratio) (%) Mean area Material (wt ppm) particles Example 1 (Fe.sub.50Pt.sub.50).sub.60C.sub.40 96.6 2.9 m.sup.2 Amorphous carbon 560 410 Example 2 (Fe.sub.40Pt.sub.45Cu.sub.15).sub.55C.sub.45 95.8 2.7 m.sup.2 Amorphous carbon 540 320 Example 3 (Fe.sub.50Pt.sub.50).sub.60C.sub.40 96.9 1.0 m.sup.2 Amorphous carbon 870 230 Example 4 (Fe.sub.50Pt.sub.50).sub.60C.sub.40 97.6 3.2 m.sup.2 Graphite 600 170 Example 5 (Fe.sub.50Pt.sub.50).sub.60C.sub.40 97.1 2.6 m.sup.2 Amorphous carbon 280 360 Example 6 (Fe.sub.50Pt.sub.50).sub.69C.sub.10Si.sub.7O.sub.14 98.6 2.5 m.sup.2 Graphite 120 Example 7 (Fe.sub.40Pt.sub.45Cu.sub.15).sub.64C.sub.18Mg.sub.9O.sub.9 98.2 2.6 m.sup.2 Graphite 320 Example 8 (Fe.sub.60Pt.sub.40).sub.62.5C.sub.16.67Cr.sub.8.33O.sub.12.50 96.7 1.8 m.sup.2 Graphite 260 Comparative (Fe.sub.50Pt.sub.50).sub.60C.sub.40 83.6 2.7 m.sup.2 Amorphous carbon 620 9640 Example 1 Comparative (Fe.sub.50Pt.sub.50).sub.40C.sub.60 87.8 6.2 m.sup.2 Amorphous carbon 820 >20000 Example 2 Comparative (Fe.sub.40Pt.sub.45Cu.sub.15).sub.55C.sub.45 85.7 2.5 m.sup.2 Amorphous carbon 580 11210 Example 3 Comparative (Fe.sub.50Pt.sub.50).sub.69C.sub.10Si.sub.7O.sub.14 98.1 11.5 m.sup.2 Graphite 510 Example 4

(146) The present invention yields a superior effect of enabling the production of a magnetic thin film with granular structure without using an expensive simultaneous sputtering device, as well as providing a high-density FePt-based sputtering target, in which C grains are dispersed, capable of reducing the amount of particles generated during sputtering. Accordingly, the present invention is effective as a sputtering target for depositing a magnetic thin film with granular structure.