Sputtering target comprising Ni—P alloy or Ni—Pt—P alloy and production method therefor

Abstract

A method of producing a NiP alloy sputtering target, wherein a NiP alloy having a P content of 15 to 21 wt % and remainder being Ni and unavoidable impurities is melted and atomized to prepare a NiP alloy atomized powder having an average grain size of 100 m or less, the NiP alloy atomized powder is mixed with a pure Ni atomized powder, and the obtained mixed powder is hot pressed. An object of the present invention is to provide a method of producing a NiP alloy sputtering target which achieves a small deviation from an intended composition.

Claims

1. A method of producing a NiP alloy sputtering target, wherein a NiP alloy containing 15 to 17 wt % of P and remainder being Ni and unavoidable impurities is melted and atomized to prepare a NiP alloy atomized powder having an average grain size of 100 m or less, the NiP alloy atomized powder is mixed with a Ni atomized powder, and the obtained mixed powder is hot pressed to produce a sintered compact containing 1 to 10 at % of P and a remainder of Ni and unavoidable impurities.

2. The method of producing a NiP alloy sputtering target according to claim 1, wherein hot isostatic pressing is performed after the hot press.

3. A method of producing a NiPtP alloy sputtering target, wherein a NiP alloy containing 15 to 21 wt % of P and remainder being Ni and unavoidable impurities is melted and atomized to prepare a NiP alloy atomized powder having an average grain size of 100 m or less, the NiP alloy atomized powder is mixed with a Ni atomized powder and a Pt powder, and the obtained mixed powder is hot pressed to produce a sintered compact containing 1 to 10 at % of P, 1 to 30 at % of Pt, and a remainder of Ni and unavoidable impurities.

4. The method of producing a NiPtP sputtering target according to claim 3, wherein hot isostatic pressing is performed after the hot press.

Description

DETAILED DESCRIPTION

(1) [NiP Alloy Sputtering Target]

(2) The NiP alloy sputtering target of the present invention is produced based on the powder sintering method. Foremost, a NiP alloy ingot having a P (phosphorus) content of 15 to 21 wt % (25 to 33.5 at %), and remainder being Ni (nickel) and unavoidable impurities is prepared. Next, the NiP alloy ingot is melted, and the molten metal is subject to spraying, rapid cooling and solidification (so-called atomization) in an inert gas atmosphere of argon, helium, nitrogen gas or the like in order to produce a NiP alloy atomized powder having an average grain size of 100 m or less.

(3) The reason why the P content is set to 15 to 21 wt % is because if the P content is less than 15% or exceeds 21%, the melting point will be 870 C. and 880 C., respectively, and the molten metal temperature will be too low for spraying the molten metal via atomization; therefore, it is difficult to effectively prepare a fine uniform atomized powder. Accordingly, by setting the P content to 15 to 21 wt %, the melting point can be maintained at 1000 to 1100 C., and a uniform powder can be obtained when the molten metal is subject to atomization and forced cooling. Moreover, the atomized powder of the present invention takes on a spherical shape, and the specific surface area can be suppressed. Consequently, the incorporation of oxygen can be inhibited.

(4) Next, a Ni atomized powder is mixed with the foregoing NiP alloy atomized powder. The Ni mixed quantity may be adjusted suitably to achieve the intended composition in consideration of the P content in the NiP alloy atomized powder. Moreover, it is preferable to use the Ni atomized powder having an average grain size of 100 m or less. Moreover, similar to the NiP alloy atomized powder, the Ni atomized powder of the present invention takes on a spherical shape, and the specific surface area can be suppressed.

(5) Note that, it may also be possible to adjust the NiP alloy ingot and the Ni ingot, or the Ni ingot and the P powder to achieve the intended composition in advance, and melt and atomize the product in order to obtain a powder of the intended composition; but in such a case, a high temperature of roughly 1500 C. is required for the alloying process, and P having a high steam pressure easily becomes volatilized so that the compositional control becomes extremely difficult. Moreover, problems will arise in that the volatilization of P may cause contamination of the furnace body and incur a risk of causing ignition of the evaporative scaffolding or the like.

(6) Next, the obtained mixed powder is hot pressed. The hot press is performed under the conditions of 750 C. to 850 C. (the melting point of an alloy is 870 C. or higher, and heating is performed at a lower temperature) and 100 to 300 kgf/cm.sup.2. It is thereby possible to obtain a NiPt alloy sputtering target material having a density of 80% or higher, containing 1 to 10 at % of P, and remainder being Ni and unavoidable impurities. The obtained NiPt alloy sputtering target material is subject to standard processes, such as being cut into a target shape, then subject to grinding and polishing, and bonded to a backing plate, to obtain a NiP alloy sputtering target.

(7) Moreover, in order to further increase the target density, it is effective to additionally subject the hot pressed NiP alloy sputtering target material to hot isostatic pressing and/or hot leveling. The hot isostatic pressing is performed under the conditions of 750 to 850 C. and 1200 to 2000 kgf/cm.sup.2. It is thereby possible to obtain a NiP alloy target material having a density of 95% or higher.

(8) With the NiP alloy sputtering target of the present invention, the compositional variation in the target can be suppressed to be within 5%. As described above, since the evaporation of P can be inhibited, it is possible to obtain a NiP alloy atomized powder having a uniform composition. Furthermore, by using this kind of atomized powder as the sintering raw material, it is possible to further suppress the compositional variation in the target, as well as in the thin film. The compositional variation in the present invention is calculated by measuring the P content at arbitrary locations of the target, and using the following formula which incorporates the maximum value, the minimum value, and the average value thereof.
Variation={(maximum value of P content)(minimum value of P content)}/(average value of P content)

(9) For instance, in a disk-shaped target, a total of 17 points can be measured; specifically, the center, 8 equal points of R (radius), and 8 equal points located 1 cm inside from the outer periphery.

(10) Moreover, with the NiP alloy sputtering target of the present invention, the average crystal grain size of the target can be 100 m or less. Since a brittle Ni.sub.5P.sub.2 phase will be formed in a NiP alloy atomized powder having a P content of 15 to 21 wt %, the NiP alloy atomized powder can be easily refined, and by using this kind of processed powder as the sintering raw material, the average crystal grain size of the target can be refined. Furthermore, this kind of fine texture enables stable deposition, fewer generation of particles, and formation of quality films.

(11) [NiPtP Alloy Sputtering Target]

(12) The NiPtP alloy sputtering target of the present invention is produced based on the powder sintering method. Foremost, a NiP alloy ingot having a P (phosphorus) content of 15 to 21 wt % (25 to 33.5 at %), and remainder being Ni (nickel) and unavoidable impurities is prepared. The NiP alloy ingot is melted via induction heating, and the molten metal is subject to spraying, rapid cooling and solidification (so-called atomization) in an inert gas atmosphere of argon, helium, nitrogen gas or the like in order to prepare a NiP alloy atomized powder having an average grain size of 100 m or less.

(13) The reason why the P content in the NiP alloy ingot is set to 15 to 21 wt % is because if the P content is less than 15% or exceeds 21%, the melting point will be 870 C. and 880 C., respectively, and the molten metal temperature will be too low for spraying the molten metal via atomization; therefore, it is difficult to prepare a fine uniform atomized powder. Accordingly, by setting the P content to 15 to 21 wt %, the melting point can be maintained at around 1100 C., and a uniform powder can be obtained when the molten metal is subject to atomization and forced cooling.

(14) The NiP alloy powder prepared via atomization as described above will encounter a substantial level of compositional variation due to the volatilization of P, but fine adjustment can be realized since this is a powder and can be mixed with other powders as needed in consideration of the P concentration that was measured through analysis in order to achieve the intended composition of the target. Thus, there is no need to be too sensitive regarding the volatilization of P. Note that the atomized powder of the present invention takes on a spherical shape, and the specific surface area can be suppressed. Consequently, the incorporation of oxygen can be inhibited.

(15) Next, a Ni atomized powder and a Pt powder (Pt sponge) are mixed with the foregoing NiP alloy atomized powder. The mixed quantity of the Ni atomized powder and the Pt powder is adjusted suitably in consideration of the composition of the sintered compact (P: 1 to 10 at %, Pt: 1 to 30 at %, remainder is Ni and unavoidable impurities). Here, the Ni atomized powder plays the role of attenuating the P content in the NiP alloy atomized powder. Moreover, similar to the NiP alloy atomized powder, the Ni atomized powder and the Pt powder of the present invention take on a spherical shape, and the specific surface area can be suppressed.

(16) Note that, it may also be possible to prepare the NiPtP target based on the melting method; but in such a case, a high temperature of roughly 1500 C. is required for melting and alloying the Ni raw material and the Pt raw material, and, when a NiP alloy is used as the source material for adding P, P having a considerably different melting point in comparison to Ni and Pt and having a high steam pressure will become volatilized so that there is a problem in that the compositional control becomes difficult. Moreover, problems will arise in that the volatilization of P may cause contamination of the furnace body and incur a risk of causing ignition of the evaporative scaffolding or the like.

(17) Meanwhile, when only the Ni-15 to 21 wt % P alloy is melted, melting is possible at 1200 C. or lower, and the problem of the evaporation of P will not arise. Such being the case, by melting and atomizing only the Ni-15 to 21 wt % P alloy to obtain a NiP alloy powder, and by mixing with a Ni powder and a Pt powder and sintering the mixed powder, it is possible to prepare a NiPtP sputtering target with minimal evaporation of P.

(18) Next, the obtained mixed powder of the NiP powder, the Ni powder, and the Pt powder is hot pressed. When Ni and NiP react and the P content reaches the range of 10 wt % or less, the melting point of the alloy becomes 870 C. and the alloy will melt in the press mold. Thus, heating is preferably performed at a lower temperature; specifically, 750 C. to 850 C. Moreover, pressure is preferably applied under the following conditions; namely, within a range of 100 to 300 kgf/cm.sup.2 in accordance with the tolerable load of the mold. It is thereby possible to obtain a NiPtP sintered compact having a density of 90% or higher.

(19) The thus obtained sintered compact (P: 1 to 10 at %, Pt: 1 to 30 at %, remainder is Ni and unavoidable impurities) is cut into a target shape and then subject to machining such as grinding and polishing in order to prepare a NiPtP sputtering target. When performing sputtering, the sputtering target is bonded to a backing plate made from copper, copper alloy or the like, and then mounted in sputtering equipment.

(20) Moreover, in order to further increase the density of the sputtering target (sintered compact), it is effective to additionally subject the hot pressed sintered compact to hot isostatic pressing (HIP). HIP is performed under the following conditions; namely, temperature of 700 C. to 850 C. and pressure of 1000 to 2000 kgf/cm.sup.2. It is thereby possible to obtain a NiPtP sputtering target having a density of 95% or higher.

(21) Furthermore, the present invention can cause the compositional variation in the NiPtP sputtering target to be within 5%. As described above, since the evaporation of P can be inhibited according to the present invention, it is possible to obtain a NiP alloy atomized powder having a uniform composition, and, by using this kind of atomized powder as the sintering raw material, it is possible to further suppress the compositional variation in the target.

(22) The compositional variation in the present invention is calculated by measuring the P content at arbitrary locations of the target, and using the following formula which incorporates the maximum value, the minimum value, and the average value thereof.
Variation={(maximum value of P content)(minimum value of P content)}/(average value of P content)

(23) For instance, in a disk-shaped target, a total of 17 points can be measured; specifically, the center, 8 equal points of 0.5 R (radius), and 8 equal points located 1 cm inside from the outer periphery.

(24) Moreover, with the NiPtP sputtering target of the present invention, the average crystal grain size of the target can be 100 m or less. A rapidly cooled fine Ni.sub.5P.sub.2 dendrite phase is formed in the NiP alloy atomized powder having a P content of 15 to 21 wt %, and this has a relatively high melting point; therefore, crystal grain growth will not occur easily at the foregoing press temperature. Accordingly, by using this kind of processed powder as the sintering raw material, the crystal grains can be refined. Furthermore, this kind of fine texture enables stable deposition, fewer particles, and formation of quality films.

EXAMPLES

(25) The Examples are now explained. Note that these Examples merely illustrate embodiments of the present invention, and the present invention is not limited by these Examples. In other words, the present invention covers other modes and modifications that are included in the technical concept of this invention.

Example 1-1

(26) A NiP alloy ingot having a P content of 17 wt % was melted via induction heating, and gas atomization was used to obtain a Ni-17 wt % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Moreover, the grain size of this raw material powder was 120 m. Next, a Ni atomized powder having a grain size of 100 m was mixed with the NiP alloy atomized powder to attain a P content of 1 at %. Next, the obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiP alloy sintered compact having a P content of 1 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(27) The thus obtained NiP alloy sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 5%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 100 m. Subsequently, this sputtering target was diffusion-bonded (instead, In-bonding may be adopted) to a backing plate made from copper alloy to prepare an assembly of a NiP alloy sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiP alloy thin film. The generation of particles in the obtained thin film was examined. The result was 5 particles. The foregoing results are shown in Table 1.

(28) Sputtering deposition was performed based on the following conditions (the same conditions were used in the ensuing Examples and Comparative Examples).

(29) <deposition conditions>

(30) Power source: DC system

(31) Power: 15 kW

(32) Ultimate vacuum: 510.sup.8 Torr

(33) Atmosphere gas composition: Ar

(34) Sputter gas pressure: 510.sup.3 Torr

(35) Sputtering time: 15 seconds

Example 1-2

(36) A NiP alloy ingot having a P content of 17 wt % was melted via induction heating, and gas atomization was used to obtain a Ni-17 wt % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Moreover, the grain size of this raw material powder was 120 m. Next, a Ni atomized powder having a grain size of 100 m was mixed with the NiP alloy atomized powder to attain a P content of 2 at %. Next, the obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiP alloy sintered compact having a P content of 1 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(37) The thus obtained NiP alloy sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 4%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 100 m. Subsequently, this sputtering target was diffusion-bonded (instead, In-bonding may be adopted) to a backing plate made from copper alloy to prepare an assembly of a NiP alloy sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiP alloy thin film. The generation of particles in the obtained thin film was examined. The result was 5 particles.

Example 1-3

(38) A NiP alloy ingot having a P content of 17 wt % was melted via induction heating, and gas atomization was used to obtain a Ni-17 wt % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Moreover, the grain size of this raw material powder was 120 m. Next, a Ni atomized powder having a grain size of 100 m was mixed with the NiP alloy atomized powder to attain a P content of 5 at %. Next, the obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiP alloy sintered compact having a P content of 1 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(39) The thus obtained NiP alloy sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 3%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method (method of examining crystal grain size) based on JISH0501. Consequently, the average crystal grain size was 100 m. Subsequently, this sputtering target was diffusion-bonded (instead, In-bonding may be adopted) to a backing plate made from copper alloy to prepare an assembly of a NiP alloy sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiP alloy thin film. The generation of particles in the obtained thin film was examined. The result was 5 particles.

Example 1-4

(40) A NiP alloy ingot having a P content of 17 wt % was melted via induction heating, and gas atomization was used to obtain a Ni-17 wt % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Moreover, the grain size of this raw material powder was 120 m. Next, a Ni atomized powder having a grain size of 100 m was mixed with the NiP alloy atomized powder to attain a P content of 10 at %. Next, the obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiP alloy sintered compact having a P content of 1 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(41) The thus obtained NiP alloy sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 2%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 100 m. Subsequently, this sputtering target was diffusion-bonded (instead, In-bonding may be adopted) to a backing plate made from copper alloy to prepare an assembly of a NiP alloy sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiP alloy thin film. The generation of particles and compositional variation in the obtained thin film were examined. The result was 5 particles.

Comparative Example 1-1

(42) A NiP alloy ingot and a Ni ingot were melted via induction heating to achieve a P content of 1 at %, and gas atomization was used to prepare a powder. Consequently, a Ni-0.8 at % P alloy atomized powder was obtained. P evaporated within the device and the composition deviated from the intended composition.

Comparative Example 1-2

(43) A NiP alloy ingot and a Ni ingot were melted via induction heating to achieve a P content of 2 at %, and gas atomization was used to prepare a powder. Consequently, a Ni-1.8 at % P alloy atomized powder was obtained. P evaporated within the device and the composition deviated from the intended composition.

Comparative Example 1-3

(44) A NiP alloy ingot and a Ni ingot were melted via induction heating to achieve a P content of 5 at %, and gas atomization was used to prepare a powder. Consequently, a Ni-4.5 at % P alloy atomized powder was obtained. P evaporated within the device and the composition deviated from the intended composition.

Comparative Example 1-4

(45) A NiP alloy ingot and a Ni ingot were melted via induction heating to achieve a P content of 10 at %, and gas atomization was used to prepare a powder. Consequently, a Ni-9.7 at % P alloy atomized powder was obtained. P evaporated within the device and the composition deviated from the intended composition.

(46) TABLE-US-00001 TABLE 1 HP conditions Target Powder Temperature Pressure Sintered compact Raw material powder composition composition ( C.) (kgf) composition Example 1-1 Ni17 wt % P atomized + Ni atomized Ni1 at % P Ni1 at % P 830 300 Ni1 at % P Example 1-2 Ni17 wt % P atomized + Ni atomized Ni2 at % P Ni2 at % P 830 300 Ni2 at % P Example 1-3 Ni17 wt % P atomized + Ni atomized Ni5 at % P Ni5 at % P 830 300 Ni5 at % P Example 1-4 Ni17 wt % P atomized + Ni atomized Ni10 at % P Ni10 at % P 830 300 Ni10 at % P Comparative NiP + Ni melted .fwdarw. atomized Ni1 at % P Ni0.8 at % P Example 1-1 Comparative NiP + Ni melted .fwdarw. atomized Ni2 at % P Ni1.8 at % P Example 1-2 Comparative NiP + Ni melted .fwdarw. atomized Ni5 at % P Ni4.5 at % P Example 1-3 Comparative NiP + Ni melted .fwdarw. atomized Ni10 at % P Ni9.7 at % P Example 1-4 HIP conditions Deviation Density after Temperature Pressure Density after Number of Compositional after HP HP (%) ( C.) (kgf) HIP (%) particles variation (%) Example 1-1 None 80 830 1500 95 5 5 Example 1-2 None 80 830 1500 95 5 4 Example 1-3 None 80 830 1500 95 5 3 Example 1-4 None 80 830 1500 95 5 2 Comparative Example 1-1 Comparative Example 1-2 Comparative Example 1-3 Comparative Example 1-4

Example 2-1

(47) A NiP alloy ingot containing 17 at % of P was melted via induction heating, and gas atomization was used to obtain a Ni-17 at % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Next, a Ni atomized powder and a Pt powder were mixed with the NiP alloy atomized powder. The obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiPtP-based sintered compact having a Pt content of 20 at %, a P content of 1 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(48) The thus obtained NiPtP sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 4%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 60 m. Subsequently, this sputtering target was diffusion-bonded (instead, In-bonding may be adopted) to a backing plate made from copper alloy to prepare an assembly of a NiPtP alloy sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiPtP alloy thin film. The generation of particles and compositional variation in the obtained thin film were examined. The result was 50 particles.

Example 2-2

(49) A NiP alloy ingot containing 18 at % of P was melted via induction heating, and gas atomization was used to obtain a Ni-18 at % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Next, a Ni atomized powder and a Pt powder were mixed with the NiP alloy atomized powder. The obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiPtP sintered compact having a Pt content of 30 at %, a P content of 1 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(50) The thus obtained NiPtP sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 4%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 70 m. Subsequently, this sputtering target was diffusion-bonded to a backing plate made from copper alloy to prepare an assembly of a NiPtP sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiPtP thin film. The generation of particles and compositional variation in the obtained thin film were examined. The result was 100 particles.

Example 2-3

(51) A NiP alloy ingot containing 19 at % of P was melted via induction heating, and gas atomization was used to obtain a Ni-19 at % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Next, a Ni atomized powder and a Pt powder were mixed with the NiP alloy atomized powder. The obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiPtP alloy sintered compact having a Pt content of 10 at %, a P content of 2 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(52) The thus obtained NiPtP sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 4%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 65 m. Subsequently, this sputtering target was diffusion-bonded to a backing plate made from copper alloy to prepare an assembly of a NiPtP sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiPtP thin film. The generation of particles and compositional variation in the obtained thin film were examined. The result was 50 particles.

Example 2-4

(53) A NiP alloy ingot containing 20 at % of P was melted via induction heating, and gas atomization was used to obtain a Ni-20 at % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Next, a Ni atomized powder and a Pt powder were mixed with the NiP alloy atomized powder. The obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiPtP sintered compact having a Pt content of 20 at %, a P content of 2 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(54) The thus obtained NiPtP sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 4%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 70 m. Subsequently, this sputtering target was diffusion-bonded to a backing plate made from copper alloy to prepare an assembly of a NiPtP sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiPtP thin film. The generation of particles and compositional variation in the obtained thin film were examined. The result was 50 particles.

Example 2-5

(55) A NiP alloy ingot containing 21 at % of P was melted via induction heating, and gas atomization was used to obtain a Ni-21 at % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Next, a Ni atomized powder and a Pt powder were mixed with the NiP alloy atomized powder. The obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiPtP sintered compact having a Pt content of 20 at %, a P content of 5 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(56) The thus obtained NiPtP sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 4%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 80 m. Subsequently, this sputtering target was diffusion-bonded to a backing plate made from copper alloy to prepare an assembly of a NiPtP sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiPtP thin film. The generation of particles and compositional variation in the obtained thin film were examined. The result was 50 particles.

Example 2-6

(57) A NiP alloy ingot containing 22 at % of P was melted via induction heating, and gas atomization was used to obtain a Ni-22 at % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Next, a Ni atomized powder and a Pt powder were mixed with the NiP alloy atomized powder. The obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiPtP sintered compact having a Pt content of 30 at %, a P content of 5 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(58) The thus obtained NiPtP sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 4%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 75 m. Subsequently, this sputtering target was diffusion-bonded to a backing plate made from copper alloy to prepare an assembly of a NiPtP sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiPtP thin film. The generation of particles and compositional variation in the obtained thin film were examined. The result was 100 particles.

Example 2-7

(59) A NiP alloy ingot containing 23 at % of P was melted via induction heating, and gas atomization was used to obtain a Ni-23 at % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Next, a Ni atomized powder and a Pt powder were mixed with the NiP alloy atomized powder. The obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiPtP sintered compact having a Pt content of 10 at %, a P content of 10 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(60) The thus obtained NiPtP sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 4%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 70 m. Subsequently, this sputtering target was diffusion-bonded to a backing plate made from copper alloy to prepare an assembly of a NiPtP sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiPtP thin film. The generation of particles and compositional variation in the obtained thin film were examined. The result was 50 particles.

Example 2-8

(61) A NiP alloy ingot containing 24 at % of P was melted via induction heating, and gas atomization was used to obtain a Ni-24 at % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Next, a Ni atomized powder and a Pt powder were mixed with the NiP alloy atomized powder. The obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiPtP sintered compact having a Pt content of 20 at %, a P content of 10 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(62) The thus obtained NiPtP sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 4%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 70 m. Subsequently, this sputtering target was diffusion-bonded to a backing plate made from copper alloy to prepare an assembly of a NiPtP sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiPtP thin film. The generation of particles and compositional variation in the obtained thin film were examined. The result was 50 particles.

Example 2-9

(63) A NiP alloy ingot containing 25 at % of P was melted via induction heating, and gas atomization was used to obtain a Ni-25 at % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Next, a Ni atomized powder and a Pt powder were mixed with the NiP alloy atomized powder. The obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiPtP sintered compact having a Pt content of 5 at %, a P content of 1 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(64) The thus obtained NiPtP sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 4%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 70 m. Subsequently, this sputtering target was diffusion-bonded to a backing plate made from copper alloy to prepare an assembly of a NiPtP sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiPtP thin film. The generation of particles and compositional variation in the obtained thin film were examined. The result was 50 particles.

Example 2-10

(65) A NiP alloy ingot containing 26 at % of P was melted via induction heating, and gas atomization was used to obtain a Ni-26 at % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Next, a Ni atomized powder and a Pt powder were mixed with the NiP alloy atomized powder. The obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiPtP alloy sintered compact having a Pt content of 5 at %, a P content of 2 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(66) The thus obtained NiPtP alloy sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 4%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 70 m. Subsequently, this sputtering target was diffusion-bonded to a backing plate made from copper alloy to prepare an assembly of a NiPtP sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiPtP thin film. The generation of particles and compositional variation in the obtained thin film were examined. The result was 50 particles.

Example 2-11

(67) A NiP alloy ingot containing 27 at % of P was melted via induction heating, and gas atomization was used to obtain a Ni-27 at % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Next, a Ni atomized powder and a Pt powder were mixed with the NiP alloy atomized powder. The obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiPtP sintered compact having a Pt content of 5 at %, a P content of 5 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(68) The thus obtained NiPtP sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 4%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 65 m. Subsequently, this sputtering target was diffusion-bonded to a backing plate made from copper alloy to prepare an assembly of a NiPtP sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiPtP thin film. The generation of particles and compositional variation in the obtained thin film were examined. The result was 100 particles.

Example 2-12

(69) A NiP alloy ingot containing 28 at % of P was melted via induction heating, and gas atomization was used to obtain a Ni-28 at % P alloy atomized powder. The obtained atomized powder was generally of a spherical shape. Next, a Ni atomized powder and a Pt powder were mixed with the NiP alloy atomized powder. The obtained mixed powder was hot pressed under the conditions of 830 C. and 300 kgf/cm.sup.2. Consequently, a NiPtP sintered compact having a Pt content of 5 at %, a P content of 10 at % and remainder being Ni and unavoidable impurities was obtained. Moreover, the density of the obtained sintered compact was 80%. Next, the obtained sintered compact was sealed in an SUS can and subject to HIP (hot isostatic pressing) under the conditions of 830 C. and 1500 kgf/cm.sup.2. As a result, the density of the obtained sintered compact was 95%.

(70) The thus obtained NiPtP alloy sintered compact was subject to machining such as grinding and polishing to prepare a disk-shaped sputtering target having a diameter of 440 mm and a thickness of 3 mmt. The compositional variation in the obtained sputtering target was examined. Consequently, the compositional variation was within 4%. Next, the average crystal grain size of this sputtering target was examined using the crosscut method based on JISH0501. Consequently, the average crystal grain size was 70 m. Subsequently, this sputtering target was diffusion-bonded (instead, In-bonding may be adopted) to a backing plate made from copper alloy to prepare an assembly of a NiPtP sputtering target and a copper alloy backing plate. Sputtering was performed using the assembly to form a NiPtP thin film. The generation of particles and compositional variation in the obtained thin film were examined. The result was 50 particles.

Comparative Example 2-1

(71) A Ni shot, a Pt powder and a P ingot were melted via induction heating to achieve Ni-20 at % Pt-1 at % P, and gas atomization was used to prepare a powder. Consequently, a Ni-20 at % Pt-0.8 at % P atomized powder was obtained. P evaporated within the device and the composition deviated from the intended composition. Moreover, process loss caused by atomization was incurred, and the loss of Pt based on weight was 0.2%.

Comparative Example 2-2

(72) A Ni shot, a Pt powder and a Ni-17 wt % P alloy ingot were melted via induction heating to achieve Ni-20 at % Pt-1 at % P, and gas atomization was used to prepare a powder. Consequently, a Ni-20 at % Pt-0.9 at % P atomized powder was obtained. P evaporated within the device and the composition deviated from the intended composition. Moreover, process loss caused by atomization was incurred, and the loss of Pt based on weight was 0.2%.

Comparative Example 2-3

(73) A Ni shot, a Ni-20 at % Pt alloy ingot and a P ingot were melted via induction heating to achieve Ni-10 at % Pt-2 at % P, and gas atomization was used to prepare a powder. Consequently, a Ni-10 at % Pt-1.6 at % P atomized powder was obtained. P evaporated within the device and the composition deviated from the intended composition. Moreover, process loss caused by atomization was incurred, and the loss of Pt based on weight was 0.2%.

Comparative Example 2-4

(74) A Ni shot, a Ni-20 at % Pt alloy ingot and a Ni-17 wt % P alloy ingot were melted via induction heating to achieve Ni-10 at % Pt-2 at % P, and gas atomization was used to prepare a powder. Consequently, a Ni-10 at % Pt-1.7 at % P atomized powder was obtained. P evaporated within the device and the composition deviated from the intended composition. Moreover, process loss caused by atomization was incurred, and the loss of Pt based on weight was 0.2%.

(75) TABLE-US-00002 TABLE 2 HP conditions Method of obtaining Temperature Pressure raw material powder Target composition Pt loss Powder composition ( C.) (kgf) Example 2-1 Ni17 wt P atomized, Ni atomized, Ni20 at % Pt1 at % P Ni20 at % Pt1 at % P 830.0 300.0 Pt sponge Example 2-2 Ni18 wt P atomized, Ni atomized, Ni30 at % Pt1 at % P Ni30 at % Pt1 at % P 830.0 300.0 Pt sponge Example 2-3 Ni19 wt P atomized, Ni atomized, Ni10 at % Pt2 at % P Ni10 at % Pt2 at % P 830.0 300.0 Pt sponge Example 2-4 Ni20 wt P atomized, Ni atomized, Ni20 at % Pt2 at % P Ni20 at % Pt2 at % P 830.0 300.0 Pt sponge Example 2-5 Ni21 wt P atomized, Ni atomized, Ni20 at % Pt5 at % P Ni10 at % Pt2 at % P 830.0 300.0 Pt sponge Example 2-6 Ni22 wt P atomized, Ni atomized, Ni30 at % Pt5 at % P Ni20 at % Pt2 at % P 830.0 300.0 Pt sponge Example 2-7 Ni23 wt P atomized, Ni atomized, Ni10 at % Pt10 at % P Ni10 at % Pt2 at % P 830.0 300.0 Pt sponge Example 2-8 Ni24 wt P atomized, Ni atomized, Ni20 at % Pt10 at % P Ni20 at % Pt2 at % P 830.0 300.0 Pt sponge Example 2-9 Ni25 wt P atomized, Ni atomized, Ni5 at % Pt1 at % P Ni5 at % Pt1 at % P 830.0 300.0 Pt sponge Example 2-10 Ni26 wt P atomized, Ni atomized, Ni5 at % Pt2 at % P Ni5 at % Pt2 at % P 830.0 300.0 Pt sponge Example 2-11 Ni27 wt P atomized, Ni atomized, Ni5 at % Pt5 at % P Ni5 at % Pt5 at % P 830.0 300.0 Pt sponge Example 2-12 Ni28 wt P atomized, Ni atomized, Ni5 at % Pt10 at % P Ni5 at % Pt10 at % P 830.0 300.0 Pt sponge Comparative Ni, Pt, P are melted .fwdarw. atomized Ni20 at % Pt1 at % P Great Ni20 at % Pt0.8 at % P 830.0 300.0 Example 2-1 Comparative Ni, Pt, NiP are melted .fwdarw. atomized Ni20 at % Pt1 at % P Great Ni20 at % Pt0.9 at % P 830.0 300.0 Example 2-2 Comparative Ni, NiPt, P are melted .fwdarw. atomized Ni10 at % Pt2 at % P Great Ni10 at % Pt1.6 at % P 830.0 300.0 Example 2-3 Comparative Ni, NiPt, NiP are melted .fwdarw. Ni10 at % Pt2 at % P Great Ni10 at % Pt1.7 at % P 830.0 300.0 Example 2-4 atomized Compositional HIP conditions Density Compositional Density deviation after Temperature Pressure after HIP variation (%) Grain Number of after HP HP ( C.) (kgf) (%) Pt P size particles Example 2-1 80 None 830.0 1500.0 95 0.5 2.0 60 50 Example 2-2 80 None 830.0 1500.0 95 0.7 3.0 70 100 Example 2-3 80 None 830.0 1500.0 95 0.6 3.0 65 50 Example 2-4 80 None 830.0 1500.0 95 0.8 2.0 70 50 Example 2-5 80 None 830.0 1500.0 95 0.6 3.0 80 50 Example 2-6 80 None 830.0 1500.0 95 0.8 2.0 75 100 Example 2-7 80 None 830.0 1500.0 95 0.6 3.0 70 50 Example 2-8 80 None 830.0 1500.0 95 0.8 2.0 70 50 Example 2-9 80 None 830.0 1500.0 95 0.6 3.0 70 50 Example 2-10 80 None 830.0 1500.0 95 0.8 2.0 70 50 Example 2-11 80 None 830.0 1500.0 95 0.6 3.0 65 100 Example 2-12 80 None 830.0 1500.0 95 0.8 2.0 70 50 Comparative 80 Deviated Example 2-1 Comparative 80 Deviated Example 2-2 Comparative 80 Deviated Example 2-3 Comparative 80 Deviated Example 2-4

(76) The present invention can provide a high density NiP alloy sputtering target having a small compositional variation in which the evaporation of P, which is problematic in terms of safety, can be inhibited by strictly controlling the P content. Consequently, the present invention yields a superior effect of being able to form a thin film having favorable properties. Moreover, the present invention can provide a high density NiPtP alloy sputtering target based on powder metallurgy without requiring any large equipment for melting/casting and rolling processes. Consequently, the present invention yields a superior effect of being able to inhibit the generation of particles during sputtering. The sputtering target of the present invention is effective for forming thin films for use in hard disks and other magnetic recording mediums.