TWI838846B - Fe-pt based sputtering target and method of preparing the same - Google Patents

Abstract

Provided is a Fe-Pt based sputtering target and a method of preparing the same. The Fe-Pt based sputtering target includes iron, platinum, a first component and a nitride; wherein the first component is selected from the group consisting of: Ru, Mn, B, Rh, Ir, Nb, Sc, Y, Ho, Er, V, Zr and any combination thereof. Based on a total atom number of the Fe-Pt based sputtering target, a content of the first component is more than or equal to 2 at% and less than or equal to 12 at%, and a content of the nitride is more than or equal to 8 at% and less than or equal to 30 at%. Meanwhile, a content of Ca of the Fe-Pt based sputtering target is less than 20 ppm, and a content of O of the Fe-Pt based sputtering target is less than 1000 ppm; in addition, a relative density of the Fe-Pt based sputtering target is more than 98%. By controlling the content of the first component, the nitride, Ca and O of the Fe-Pt based sputtering target and the relative density of the Fe-Pt based sputtering target, the Fe-Pt based sputtering target can not only increase the resistance to oxidation, but also reduce the surface roughness of a magnetic recording layer formed by the Fe-Pt based sputtering target.

Description

Iron-platinum based target and its manufacturing method

This invention relates to an iron-platinum-based target material, in particular to an iron-platinum-based target material suitable for magnetic recording media; in addition, this invention also relates to a method for manufacturing the iron-platinum-based target material.

Magnetic recording refers to the use of the hysteresis properties of magnetic materials to store information in recording media. According to the direction of the magnetization of the magnetic head, with the consumer's demand for portable recording media, the rise of big data, and the generation of massive amounts of information, people have an increasing demand for the information storage capacity of magnetic recording media. Therefore, how to improve the recording density of magnetic recording media has always been a research focus in related fields.

Generally speaking, the layered structure of a perpendicular magnetic recording medium includes a substrate, an adhesion layer, a soft underlayer, a seed layer, an intermediate layer, a magnetic recording layer, a lubricating layer, and a cover layer from bottom to top. As the technology of perpendicular magnetic recording media matures, the magnetic recording layer of the Cobalt-Chromium-Pt alloy system is gradually approaching the magnetic recording density limit. In order to further improve the recording density of perpendicular magnetic recording media, the industry has developed a heat-assisted magnetic recording medium (HAMR medium) made of an iron-platinum alloy system. The heat energy acts on the magnetic grains of the recording bit while writing the magnetic field, raising the temperature of the magnetic grains to the Curie point. temperature), the magnetic flexibility of the magnetic particles is temporarily reduced. Since the magnetic particle size of the iron-platinum alloy can be smaller than that of the cobalt-chromium-platinum alloy, the recording density of the magnetic recording medium can be increased. In addition, since the heat-assisted magnetic recording technology will repeatedly focus and heat the same area, a magnetic composite material with high stability is required as the magnetic recording layer. The heat-assisted magnetic recording layer of the existing technology mostly uses the iron-platinum alloy system as the main component of the magnetic recording layer, and non-magnetic components such as boron nitride (BN) and carbon can be added to the iron-platinum alloy system to form a barrier between the grains of the iron-platinum alloy and reduce the magnetic coupling effect.

However, the existing FePt target has problems such as insufficient relative density and poor oxidation resistance. If the FePt target does not have sufficient oxidation resistance, when the target is not stored under appropriate conditions, the surface of the target will easily rust due to oxidation, affecting the quality of the magnetic recording layer and seriously affecting the application of the magnetic recording layer obtained by sputtering.

Furthermore, as the recording density of the disc increases and the flying height of the magnetic head decreases, the surface roughness of the film on the disc must also be reduced.

In view of the defects faced by the existing technology, the purpose of this invention is to enhance the anti-oxidation ability of the FePt-based target material, so that the FePt-based target material provided by this invention is easy to preserve and can improve the quality and yield of the magnetic recording layer formed by sputtering.

Another object of the present invention is to provide an iron-platinum-based target material, wherein an iron-platinum-based film formed by sputtering using the iron-platinum-based target material has a lower surface roughness.

To achieve the above-mentioned purpose, the present invention provides an iron-platinum-based target material, which comprises iron (Fe), platinum (Pt), a first component and a nitride; wherein the first component is selected from the group consisting of ruthenium (Ru), manganese (Mn), boron (B), rhodium (Rh), iridium (Ir), niobium (Nb), scandium (Sc), yttrium (Y), holmium (Ho), erbium (Er), vanadium (V), zirconium (Zr) and combinations thereof; wherein, based on the total number of atoms in the entire iron-platinum-based target material, the content of the first component is greater than or equal to 2 atomic percentage (atomic percentage, at%) and less than or equal to 12 at%, the content of the nitride is greater than or equal to 8 at% and less than or equal to 30 at%; the content of calcium (Ca) in the FePt-based target is less than 20 parts per million (ppm), and the content of oxygen (O) in the FePt-based target is less than 1000 ppm; wherein the relative density of the FePt-based target is greater than 98%.

By controlling the content of the first component in the iron-platinum-based target of the present invention to have the following technical characteristics at the same time: (I) the content of the first component is greater than or equal to 2 at% and less than or equal to 12 at%, (II) the content of the nitride is greater than or equal to 8 at% and less than or equal to 30 at%, (III) the calcium content in the iron-platinum-based target is less than 20 ppm, (IV) the oxygen content in the iron-platinum-based target is less than 1000 ppm, and (V) the relative density of the iron-platinum-based target is greater than 98%, the oxidation resistance of the iron-platinum-based target can be effectively improved; in addition, the iron-platinum-based film formed by sputtering of the iron-platinum-based target can also have a sufficiently small surface roughness.

Preferably, based on the total number of atoms in the entire FePt-based target, the content of iron is greater than or equal to 8 at% and less than or equal to 77 at%, but not limited thereto. More preferably, based on the total number of atoms in the entire FePt-based target, the content of iron is greater than or equal to 34 at% and less than or equal to 75 at%.

Preferably, based on the total number of atoms in the entire FePt-based target, the content of platinum is greater than or equal to 3 at% and less than or equal to 30 at%, but is not limited thereto.

Preferably, the nitride is selected from the group consisting of boron nitride (BN), aluminum nitride (AlN), vanadium nitride (VN), sintered carbide nitride (ScN), manganese nitride (MnN), titanium nitride (TiN), iron nitride (FeN), gallium nitride (GaN), nickel nitride (NiN), zirconium nitride (ZrN), niobium nitride (NbN), silicon nitride (Si ₃ N ₄ ), helium nitride (HfN), tantalum nitride (TaN), molybdenum nitride (MoN), cobalt nitride (CoN), chromium nitride (CrN) and combinations thereof. According to the present invention, when there is only one choice of nitride, the "nitride content" is the content of the single nitride; when the nitride includes two or more choices, the "nitride content" is the sum of the individual contents of these nitrides; for example, when the nitride is a combination of 7 at% boron nitride, 10 at% manganese nitride and 10 at% titanium nitride, the nitride content is 27 at%.

Preferably, the calcium content in the FePt-based target is 1 ppm to 11 ppm, but not limited thereto.

Preferably, when the oxygen content in the FePt-based target is less than 625 ppm, its anti-oxidation ability can be further improved. More preferably, the oxygen content in the FePt-based target is less than 510 ppm.

In some embodiments, the iron platinum-based target further comprises carbon (C) or carbide. Specifically, the carbide is selected from the group consisting of tungsten carbide (WC), titanium carbide (TiC), niobium carbide (NbC), tantalum carbide ( _TaCX , X=0.4 to 1), chromium carbide ( _Cr3C2 ), silicon carbide ( _SiC ), zirconium carbide (ZrC), boron carbide ( _B4C ), vanadium carbide (VC), niobium carbide (HfC), titanium carbide nitrogen (TiCN) and combinations thereof.

Specifically, the carbon in the iron platinum-based target can be in the form of diamond carbon with a three-dimensional tetrahedral structure, graphite carbon with a two-dimensional planar structure, carbon nanotubes with a one-dimensional structure, or a combination thereof, but is not limited thereto.

Preferably, based on the total number of atoms of the entire iron-platinum-based target material, the total content of carbon and carbide is greater than or equal to 10 at% and less than or equal to 20 at%, wherein the carbon content may be 0 at%, or the carbide content may be 0 at%, but is not limited thereto. Similarly, according to the present invention, when there is only one option for carbon or carbide, the "total content of carbon and carbide" is the content of the single option; when carbon and carbide include more than two options, the "total content of carbon and carbide" is the sum of the individual contents of these options; for example, when carbon or carbide is a combination of 6 at% carbon and 10 at% niobium carbide, the total content of carbon and carbide is 16 at%.

According to the present invention, the relative density of the iron-platinum-based target is greater than 98%. Preferably, the relative density of the iron-platinum-based target is greater than 98.2%, but not limited thereto. More preferably, the relative density of the iron-platinum-based target is greater than 99%, but not limited thereto. The relative density is measured using the Archimedes principle.

In addition, the invention further provides a method for manufacturing an iron-platinum-based target, which comprises the following steps: step (a): mixing an iron raw material, a platinum raw material, a first component raw material and a nitride raw material and grinding them to obtain a raw material mixture; wherein the first component is selected from the group consisting of ruthenium, manganese, boron, rhodium, iridium, niobium, arsenic, yttrium, tantalum, beryl, vanadium, zirconium and combinations thereof; based on the total number of atoms in the raw material mixture as a whole, the addition amount of the first component raw material is greater than or equal to 2 at% and less than or equal to 12 at%, and the addition amount of the nitride raw material is greater than or equal to 8 at% and less than or equal to 30 at%. at%; step (b): placing the raw material mixture in water for a stirring and washing process to obtain a washed raw material mixture; wherein the temperature of the water is greater than or equal to 55°C and less than or equal to 65°C; step (c): performing a drying process on the washed raw material mixture to obtain a dried raw material mixture; step (d): performing a hydrogen reduction process on the dried raw material mixture to obtain a reduced material; and step (e): sintering the reduced material to obtain the iron-platinum-based target material; wherein the calcium content in the iron-platinum-based target material is less than 20 ppm, and the oxygen content in the iron-platinum-based target material is less than 1000 ppm; the relative density of the iron-platinum-based target material is greater than 98%.

This invention helps to control the oxygen content of the iron-platinum-based target by limiting the usage range of the first component raw material and the nitride raw material, reducing the calcium content in the raw material mixture through water washing and drying processes, and subjecting all the raw material mixtures to a hydrogen reduction process. Therefore, when the iron-platinum-based target is subsequently formed, it can also have a relative density greater than 98%, thereby improving the oxidation resistance of the iron-platinum-based target. In addition, the iron-platinum-based film formed by sputtering using the iron-platinum-based target has a lower surface roughness.

According to the present invention, in step (a), the iron raw material can be an iron metal with a purity of more than 99%, an iron alloy with an iron content of more than 50 weight percent (wt%), or a combination thereof, but is not limited thereto. Preferably, the average particle size of the iron raw material is 5 micrometers (μm) to 80 μm.

According to the present invention, in step (B), the platinum raw material can be a platinum metal with a purity of 99% or more, a platinum alloy with a platinum content of 50 wt% or more, or a combination thereof, but is not limited thereto. Preferably, the average particle size of the platinum raw material is 1 μm to 10 μm, but is not limited thereto. By selecting a platinum raw material with an average particle size in the aforementioned range, platinum can be more easily diffused in the iron phase.

In some embodiments, the platinum raw material and the iron raw material may be an iron-platinum alloy.

Preferably, the average particle size of the first component raw material is 5 μm to 50 μm, but not limited thereto.

Preferably, the average particle size of the nitride raw material is 0.1 μm to 30 μm, but not limited thereto.

Specifically, the nitride raw material can be selected from the group consisting of boron nitride raw materials, aluminum nitride raw materials, vanadium nitride raw materials, carbendazim raw materials, manganese nitride raw materials, titanium nitride raw materials, iron nitride raw materials, gallium nitride raw materials, nickel nitride raw materials, zirconium nitride raw materials, niobium nitride raw materials, silicon nitride raw materials, uranium nitride raw materials, tantalum nitride raw materials, molybdenum nitride raw materials, cobalt nitride raw materials, chromium nitride raw materials and combinations thereof.

In some embodiments, the step (a) further comprises a carbon raw material or a carbide raw material. Preferably, the carbon raw material or the carbide raw material has an average particle size of 0.1 μm to 30 μm, but is not limited thereto.

Specifically, the carbide raw material can be selected from the group consisting of tungsten carbide raw materials, titanium carbide raw materials, niobium carbide raw materials, tungsten carbide raw materials, chromium carbide raw materials, silicon carbide raw materials, zirconium carbide raw materials, boron carbide raw materials, vanadium carbide raw materials, niobium carbide raw materials, titanium carbide nitrogen raw materials and combinations thereof.

According to the invention, in step (a), the mixing method can be any method that can evenly mix the raw materials. In addition, in step (a), a high-speed grinder can be used to perform the grinding process, but it is not limited thereto. Preferably, the grinding time in step (a) is 1 hour to 4 hours, but it is not limited thereto.

Preferably, in step (b), the ratio of the weight of the raw material mixture to the volume of the water is greater than or equal to 90 g/L and less than or equal to 110 g/L, for example, 95 g/L, 98 g/L, 100 g/L, 105 g/L, 108 g/L, but not limited thereto.

Preferably, in step (c), the duration of the drying process is greater than or equal to 6 hours and less than or equal to 18 hours, but not limited thereto. Preferably, in step (c), the temperature of the drying process is greater than or equal to 70°C and less than or equal to 90°C, for example, 75°C, 80°C, 85°C, but not limited thereto. The present invention reduces the calcium content in the raw material mixture by a water washing process, so the calcium content of the iron platinum-based target material obtained in the end is roughly equivalent to the calcium content in the raw material mixture after drying.

Preferably, in the step (d), the duration of the hydrogen reduction process is greater than or equal to 1 hour and less than or equal to 3 hours, but not limited thereto; the reduction temperature is greater than or equal to 550° C. and less than or equal to 900° C., but not limited thereto. Specifically, in the step (d), the dried raw material mixture is placed in a hydrogen atmosphere at a temperature of 550° C. to 900° C. for 1 hour to 3 hours to obtain the reduced material, but not limited thereto.

In some embodiments, the step (d) and the step (e) may further include a pre-pressing step; that is, after obtaining the reduced material in the step (d), a pre-pressing step may be performed successively, and the pre-pressing step may be any means capable of pressing the reduced material into a fixed shape. For example, the pre-pressing step may be placing the reduced material in a hydraulic press and pre-pressing it at a pressure of about 15 bar to 110 bar, but is not limited thereto.

According to the present invention, in step (e), the sintering method may be hot pressing (HP), hot isostatic pressing (HIP) or spark plasma sintering (SPS), or two or more of the above sintering methods may be combined for sintering. Preferably, in step (e), the sintering temperature may be greater than or equal to 700°C and less than or equal to 1200°C, and the sintering pressure may be greater than or equal to 220 bar and less than or equal to 1850 bar. For example, when HP is used for sintering, the sintering temperature may be 800°C to 1200°C, the sintering pressure may be 350 bar to 400 bar, and the sintering time may be 1 hour to 4 hours, but not limited thereto; when HIP is used for sintering, the sintering temperature may be 800°C to 1200°C, the sintering pressure may be 1200 bar to 1850 bar, and the sintering time may be 1 hour to 4 hours, but not limited thereto; when SPS is used for sintering, the sintering temperature may be 700°C to 1200°C, the sintering pressure may be 220 bar to 1200 bar, and the sintering time may be 5 minutes to 2 hours, but not limited thereto.

In this manual, if there is no special indication, the range expressed by "a small number to a large number" means that the range is greater than or equal to the small number and less than or equal to the large number. For example, if the grinding time is 1 hour to 4 hours, it means that the grinding time range is "greater than or equal to 1 hour and less than or equal to 4 hours".

In order to verify the material composition of the iron-platinum-based target, the influence of water washing, hydrogen reduction and other processes in the preparation method on the iron-platinum-based target, several iron-platinum-based targets are listed below as examples to explain in detail the implementation method of the present invention. A person with ordinary knowledge in the relevant technical field can easily understand the advantages and effects that can be achieved by the present invention through the contents of this manual, and make various modifications and changes without deviating from the spirit of the present invention to implement or apply the contents of the present invention.

Embodiment 1 to 14 (E1-E14) ：FePt based target

First, according to the composition of the iron-platinum-based target listed in Table 1-1, appropriate amounts of iron powder with an average particle size of 10 μm, platinum powder with an average particle size of 5 μm, first component powder with an average particle size of 15 μm, and nitride powder with an average particle size of 5 μm are weighed and mixed in a high-speed grinder, and then ground for 1 to 4 hours to obtain a raw material mixture.

Secondly, the raw material mixture is placed in water at a temperature of 60°C and stirred and washed for 3 hours to obtain a washed raw material mixture; wherein the ratio of the weight of the raw material mixture to the volume of water is 100 g/1L. Then, the washed raw material mixture is placed in an oven set at a temperature of 80°C and dried for 12 hours to obtain a dried raw material mixture, at which time, the calcium content of the dried raw material mixture is less than 20 ppm.

Then, the dried raw material mixture is placed in a hydrogen atmosphere at 750° C. for reduction for 1 hour to obtain a reduced material.

Next, the reduced material is placed in a hydraulic press and pre-pressed at a pressure of about 20 bar, and then sintered according to the sintering process and sintering temperature listed in Table 1-2 to obtain the iron-platinum-based target materials of Examples 1 to 14; wherein, if HP is used for sintering, the sintering pressure is about 380 bar and the sintering time is 3 hours; if HIP is used for sintering, the sintering pressure is about 1750 bar and the sintering time is 3 hours; if SPS is used for sintering, the sintering pressure is about 252 bar and the sintering time is 10 minutes.

In Table 1-1, the composition of the FePt-based target of Examples 1 to 14 can be represented by the general formula of aFe-bPt-cX-dY, and the oxygen content in each FePt-based target is less than 1000 ppm; wherein a represents the content ratio of the number of iron atoms relative to the total number of atoms of the FePt-based target; b represents the content ratio of the number of platinum atoms relative to the total number of atoms of the FePt-based target; c represents the content ratio of the number of atoms of the first component relative to the total number of atoms of the FePt-based target, and X represents the first component, which can be selected from ruthenium, manganese, boron, rhodium, iridium, niobium, arsenic, yttrium, tantalum, erbium, vanadium, zirconium and the like. The target material is a group of a plurality of materials, wherein d represents the content ratio of the number of atoms of the nitride relative to the total number of atoms of the Fe-Pb-based target material, and Y represents a nitride selected from the group consisting of boron nitride, aluminum nitride, vanadium nitride, carbendazim nitride, manganese nitride, titanium nitride, iron nitride, gallium nitride, nickel nitride, zirconium nitride, niobium nitride, silicon nitride, uranium nitride, tantalum nitride, molybdenum nitride, cobalt nitride, chromium nitride, and combinations thereof. For example, when the nitride is boron nitride, d represents the content ratio of the sum of the number of nitrogen atoms and the number of boron atoms relative to the total number of atoms of the Fe-Pb-based target material.

Among them, taking the iron platinum-based target of Example 1 as an example, relative to the total number of atoms of the iron platinum-based target, Fe accounts for 46 at%, Pt accounts for 25 at%, the first component is Ru and B, and Ru accounts for 4 at%, B accounts for 1 at%, so the first component accounts for 5 at% in total; and the nitride is AlN, which accounts for 24 at%. In addition, taking the iron platinum-based target of Example 2 as an example, relative to the total number of atoms of the iron platinum-based target, Fe accounts for 62 at%, Pt accounts for 13 at%, the first component is V and Zr, and V accounts for 4 at%, Zr accounts for 4 at%, so the first component accounts for 8 at% in total; and the nitride is ScN and VN, and ScN accounts for 7 at%, VN accounts for 10 at%, so the nitride accounts for 17 at%.

Embodiment 15 to 20 (E15-E20) : Iron platinum based target ( Contains carbon )

The manufacturing process of Examples 15 to 20 is similar to that of Examples 1 to 14, that is, appropriate amounts of powders of different components are weighed and mixed, ground, washed, dried, hydrogen reduced, pre-pressed, and sintered to obtain the iron-platinum-based targets of Examples 15 to 20.

The main difference between Examples 15 to 20 and Examples 1 to 14 is that carbon and/or carbide components are added. That is, according to the composition of the iron-platinum-based target material listed in Table 1-1, appropriate amounts of iron powder with an average particle size of 10 μm, platinum powder with an average particle size of 5 μm, first component powder with an average particle size of 15 μm, nitride powder with an average particle size of 5 μm, and carbon powder or carbide powder with an average particle size of 3 μm are weighed and placed in a high-speed grinder for mixing.

In Table 1-1, the composition of the Fe-Pt-based target of Examples 15 to 20 can be represented by the general formula of aFe-bPt-cX-dY-eZ; wherein a, b, c, X, d, and Y respectively represent the content ratio of the number of iron atoms relative to the total number of atoms of the Fe-Pt-based target, the content ratio of the number of platinum atoms relative to the total number of atoms of the Fe-Pt-based target, the selection of the first component and the content of its atomic number relative to the total number of atoms of the Fe-Pt-based target as described above. The ratio of nitride and the content ratio of its atomic number relative to the total atomic number of the iron-platinum-based target, and Z represents the selection of carbon and/or carbide, the carbide can be selected from the group consisting of tungsten carbide, titanium carbide, niobium carbide, tantalum carbide, chromium carbide, silicon carbide, zirconium carbide, boron carbide, vanadium carbide, arsenic carbide, titanium carbide nitride and combinations thereof, and e represents the content ratio of carbon and/or carbide atoms relative to the total atomic number of the iron-platinum-based target.

Comparison Example 1 (C1) ：FePt based target

The method used for preparing the iron platinum-based target material of Comparative Example 1 is substantially the same as the method for preparing the iron platinum-based target material of Example 1, and the main differences are: Comparative Example 1 does not undergo the steps of water washing, drying, and hydrogen reduction, and the sintering temperature is slightly different. That is, according to the composition of the iron platinum-based target material listed in Table 1-1, the powders of each raw material are weighed, and after the steps of mixing, grinding, pre-pressing, and sintering, the iron platinum-based target material of Comparative Example 1 is prepared. The sintering process and sintering temperature of Comparative Example 1 are listed in Table 1-2.

Comparison Example 2 to 5 (C2-C5) ：FePt based target

The methods used for preparing the iron-platinum-based targets of Comparative Examples 2 to 5 are substantially the same as the methods for preparing the iron-platinum-based targets of Examples 1 to 14, with the main differences being that: Comparative Example 2 does not simultaneously control the contents of the first component raw material and the nitride raw material in the raw material mixture, and does not control the calcium content in the iron-platinum-based target; Comparative Example 3 does not control the content of the first component raw material in the raw material mixture, and does not control the oxygen content in the iron-platinum-based target; Comparative Examples 4 and 5 do not control the content of the nitride raw material in the raw material mixture, do not undergo the steps of water washing, drying, and hydrogen reduction, and do not control the oxygen content and calcium content in the iron-platinum-based target. The composition, calcium content and oxygen content of the FePt-based targets of Comparative Examples 2 to 5 are listed in Table 1-1, and the sintering process and sintering temperature are listed in Table 1-2.

Comparison Example 6 to 11 (C6-C11) : Iron platinum based target ( Contains carbon )

The methods used for preparing the iron-platinum-based targets of Comparative Examples 6 to 11 are substantially the same as the methods for preparing the iron-platinum-based targets of Examples 15 to 20, with the main differences being that: Comparative Examples 6 and 7 did not undergo the steps of water washing, drying, and hydrogen reduction, and did not control the oxygen content and calcium content in the iron-platinum-based targets; Comparative Example 8 did not undergo the step of hydrogen reduction, and did not control the oxygen content in the iron-platinum-based targets; Comparative Example 9 did not undergo the steps of water washing and drying, and did not control the calcium content in the iron-platinum-based targets; Comparative Examples 10 and 11 did not control the content of the first component raw material in the raw material mixture, did not undergo the steps of water washing, drying, and hydrogen reduction, and did not control the oxygen content and calcium content in the iron-platinum-based targets. The composition, calcium content and oxygen content of the iron platinum-based target materials of Examples 6 to 11 are listed in Table 1-1, and the sintering process and sintering temperature are listed in Table 1-2. Table 1-1 Composition, calcium content and oxygen content of the iron platinum-based target materials of Examples 1 to 20 and Comparative Examples 1 to 11 Group Composition of FePt target Ca content (ppm) O content (ppm) E1 46Fe-25Pt-4Ru-1B-24AlN 10.9 86 E2 62Fe-13Pt-4V-4Zr-7ScN-10VN 8.1 617 E3 38Fe-25Pt-10Mn-7BN-10MnN-10TiN 17.9 248 E4 50Fe-8Pt-1Er-11Ho-10FeN-20GaN 18.3 793 E5 59Fe-18Pt-1Sc-3Nb-9BN-10NiN 6.6 422 E6 47Fe-23Pt-3Er-5Ir-5ZrN-7NbN-10Si ₃ N ₄ 12.5 495 E7 69Fe-17Pt-2Ir-12VN 0.7 854 E8 60Fe-20Pt-5Mn-15BN 1.3 371 E9 38Fe-30Pt-1Ru-6Rh-10AlN-15ZrN 4.2 513 E10 63Fe-10Pt-9Zr-10BN-8AlN 10.4 620 E11 47Fe-29Pt-4Er-10HfN-10GaN 5.8 589 E12 64Fe-5Pt-3Ho-5Sc-5BN-5Si ₃ N ₄ -13TiN 11.0 481 E13 73Fe-10Pt-1Y-1Ho-2V-5NbN-8FeN 2.6 297 E14 57Fe-15Pt-2Er-5Sc-5TaN-5MnN-5MoN-6NiN 9.8 743 E15 43Fe-22Pt-4Y-7Nb-10AlN-14C 4.3 366 E16 38Fe-30Pt-6Rh-8BN-18WC 1.2 72 E17 34Fe-21Pt-2V-5Rh-10MoN-18Si ₃ N ₄ -10TiC 16.4 201 E18 39Fe-3Pt-12Sc-10AlN-20ScN-6C-10NbC 3.7 926 E19 36Fe-19Pt-5Zr-10ZrN-11TiN-4C-5TaC-10Cr ₃ C ₂ 10.6 586 E20 39Fe-27Pt-1V-2Mn-11HfN-20SiC 1.6 187 C1 46Fe-25Pt-4Ru-1B-24AlN 211.7 2001 C2 49Fe-15Pt-1Zr-5AlN-10TiN-20ZrN 26.1 861 C3 45Fe-10Pt-10Er-10Y-25GaN 15.2 1147 C4 79Fe-8Pt-6V-7BN 105.9 3540 C5 54Fe-11Pt-3Sc-12ZrN-20MnN 304.1 3686 C6 71Fe-2Pt-1Ir-4Ho-14AlN-8C 192.8 3934 C7 29Fe-22Pt-3Nb-10BN-11AlN-10C-15TaC 203.4 1865 C8 27Fe-38Pt-5B-6Mn-9BN-15WC 11.7 1779 C9 19Fe-27Pt-3Zr-6Ir-10FeN-15ScN-20SiC 269.6 878 C10 59Fe-15Pt-1Er-15ZrN-10TiC 127.5 3262 C11 15Fe-23Pt-6Y-8Ho-10TaN-13GaN-5C-20ZrC 394.3 2794 Table 1-2 Whether or not water washing and hydrogen reduction steps were performed in the preparation of Examples 1 to 20 and Comparative Examples 1 to 11, the sintering process used, and the sintering temperature Group Whether to wash with water Whether there is hydrogen reduction Sintering process Sintering temperature E1 have have HP 1000°C E2 have have HP 1000°C E3 have have HP 1050°C E4 have have HP 1100°C E5 have have HP 1000°C E6 have have HP 1100°C E7 have have HP 1000°C E8 have have HIP 950°C E9 have have HIP 1000°C E10 have have HIP 1050°C E11 have have HIP 1000°C E12 have have HIP 1100°C E13 have have HIP 900°C E14 have have HIP 1050°C E15 have have SPS 900°C E16 have have SPS 950°C E17 have have SPS 1000°C E18 have have SPS 850°C E19 have have SPS 900°C E20 have have SPS 850°C C1 without without HP 900°C C2 have have SPS 1000°C C3 have have SPS 1050°C C4 without without HIP 700°C C5 without without HIP 850°C C6 without without HIP 1000°C C7 without without SPS 850°C C8 have without SPS 1000°C C9 without have SPS 950°C C10 without without HP 1000°C C11 without without HP 1100°C

analyze 1 : Calcium content of FePt target

The iron-platinum-based alloy rough pieces obtained after sintering in Examples 1 to 20 and Comparative Examples 1 to 11 were cut by wire cutting to obtain 2 cm × 2 cm test pieces, and then the black skin on the surface was removed and cleaned.

Subsequently, the samples of the FePt-based targets of Examples 1 to 20 and Comparative Examples 1 to 11 were placed in a GD-MS to measure the calcium content, and the measurement results are recorded in Table 2.

analyze 2 ：Oxygen content of FePb-based target

The iron-platinum-based alloy rough blanks obtained after sintering in Examples 1 to 20 and Comparative Examples 1 to 11 were processed by wire cutting, and then the black skin on the surface was removed and cleaned, and 50 mg to 100 mg of each were taken as the test samples. Then, the test samples of each group were placed in a graphite crucible, and heated and burned in a helium atmosphere to convert the oxygen content in the test samples into carbon monoxide. Finally, the oxygen and nitrogen analyzer (model EMGA-620W manufactured by HORIBA) was used to detect the oxygen content of each test sample by non-dispersive infrared absorption method, and the test results are listed in Table 2.

analyze 3 : Target relative density

The iron-platinum-based alloy rough blanks obtained after sintering of Examples 1 to 20 and Comparative Examples 1 to 11 were used to obtain 1 cm × 1 cm test pieces by wire cutting, and then the surface black skin was removed and cleaned. Then, the relative density of the iron-platinum-based target materials of Examples 1 to 20 and Comparative Examples 1 to 11 was obtained by the Archimedean method, and the results are recorded in Table 2.

analyze 4 ：Target material antioxidant capacity

The iron-platinum-based alloy rough billets obtained after sintering in Examples 1 to 20 and Comparative Examples 1 to 11 were cut by wire cutting to obtain 5 cm × 5 cm test pieces, and then the black skin on the surface was removed and cleaned.

Next, the iron-platinum-based target specimens of Examples 1 to 20 and Comparative Examples 1 to 11 were placed in a high temperature and high humidity environment with a temperature of 60°C and a relative humidity of 85%, and the surface of each specimen was inspected every hour with an optical microscope (OM) with a magnification of 100 times to see if there was any rust spot, until the surface of the specimen showed obvious visual rust corrosion due to oxidation, and the total time elapsed was recorded as the rust spot appearance time. Among them, the images taken with an optical microscope are shown in Figures 1 and 2. Figure 1 is an image of the iron-platinum-based target material sample of Example 1 after 172 hours of anti-oxidation test, magnified 100 times by an optical microscope, and Figure 2 is an image of the iron-platinum-based target material sample of Comparative Example 4 after 2 hours of anti-oxidation test, magnified 100 times by an optical microscope. Obviously, the time for Example 1 to rust due to oxidation is much longer than the time required for Comparative Example 4.

The longer the "rust spot appearance time", the better the antioxidant ability of the iron platinum-based target material, and the shorter the "rust spot appearance time", the worse the antioxidant ability of the iron platinum-based target material. The rust spot appearance time of the iron platinum-based target materials of Examples 1 to 20 and Comparative Examples 1 to 11 in a high temperature and high humidity environment is listed in Table 2. In this work, a rust spot appearance time greater than 75 hours is judged to have passed the antioxidant ability test.

analyze 5 :Surface roughness

The iron platinum-based targets of Examples 1 to 20 and Comparative Examples 1 to 11 were processed by wire cutting and grinding to obtain circular targets with a diameter of 3 inches and a thickness of 5 mm. Then, each target was placed in a magnetron sputtering machine (manufacturer: Golden) with a continuous argon flow rate of 50 sccm (Standard Cubic Centimeter per Minute) and a vacuum degree of 0.001 torr to 0.01 torr. The dirt on the surface of the target was first removed by pre-sputtering (power: 100 watts (W); time: 600 seconds) to obtain a target to be sputtered for subsequent sputtering. Next, the target to be sputtered was placed in a sputtering environment with an argon gas flow rate of 50 sccm and a vacuum degree of 10 ^-2 torr to 10 ^-3 torr, and a sputtering process was performed for 600 seconds at a power of 80 W on a glass specimen with a diameter of 2 inches and a thickness of 0.5 cm, thereby obtaining a sputtered film for each group.

Subsequently, the surface roughness of each sputtered film was analyzed according to the ISO 25178 standard method by using the three-dimensional (3D) imaging function of a shape analysis laser confocal white light interference microscope (model: VK-X3000, manufacturer: KEYENCE) to obtain the arithmetic mean deviation (Ra) and maximum height of profile (Rz) of each sputtered film. The measurement results of each group are recorded in Table 2. The maximum height represents the sum of the height of the highest peak and the depth of the deepest valley in the roughness curve on the reference length.

Since each sputtered film is made by the same sputtering method, the difference in surface roughness of each sputtered film is mainly due to the characteristics of the sputtering target. In this work, a single layer of sputtered film with Ra less than 20 nanometers (nm) and Rz less than 50 nm is judged to pass the surface roughness test. Table 2 Group Composition of FePt target Relative density Rust spot appearance time (hr) Roughness of sputtered films Ra (nm) Rz (nm) E1 46Fe-25Pt-4Ru-1B-24AlN 99.24% 172 6 twenty four E2 62Fe-13Pt-4V-4Zr-7ScN-10VN 98.91% 109 10 39 E3 38Fe-25Pt-10Mn-7BN-10MnN-10TiN 98.26% 138 9 33 E4 50Fe-8Pt-1Er-11Ho-10FeN-20GaN 98.57% 106 11 41 E5 59Fe-18Pt-1Sc-3Nb-9BN-10NiN 99.45% 128 8 31 E6 47Fe-23Pt-3Er-5Ir-5ZrN-7NbN-10Si ₃ N ₄ 98.73% 126 10 36 E7 69Fe-17Pt-2Ir-12VN 99.80% 85 13 40 E8 60Fe-20Pt-5Mn-15BN 98.85% 149 8 29 E9 38Fe-30Pt-1Ru-6Rh-10AlN-15ZrN 99.07% 119 7 32 E10 63Fe-10Pt-9Zr-10BN-8AlN 99.31% 111 9 35 E11 47Fe-29Pt-4Er-10HfN-10GaN 99.68% 134 8 31 E12 64Fe-5Pt-3Ho-5Sc-5BN-5Si ₃ N ₄ -13TiN 99.82% 126 14 47 E13 73Fe-10Pt-1Y-1Ho-2V-5NbN-8FeN 99.13% 140 3 twenty three E14 57Fe-15Pt-2Er-5Sc-5TaN-5MnN-5MoN-6NiN 99.69% 92 10 41 E15 43Fe-22Pt-4Y-7Nb-10AlN-14C 98.72% 138 9 33 E16 38Fe-30Pt-6Rh-8BN-18WC 99.01% 176 5 17 E17 34Fe-21Pt-2V-5Rh-10MoN-18Si ₃ N ₄ -10TiC 98.96% 155 7 27 E18 39Fe-3Pt-12Sc-10AlN-20ScN-6C-10NbC 99.19% 79 10 46 E19 36Fe-19Pt-5Zr-10ZrN-11TiN-4C-5TaC-10Cr ₃ C ₂ 99.43% 111 9 38 E20 39Fe-27Pt-1V-2Mn-11HfN-20SiC 98.64% 167 6 26 C1 46Fe-25Pt-4Ru-1B-24AlN 87.65% 5 twenty three 87 C2 49Fe-15Pt-1Zr-5AlN-10TiN-20ZrN 98.23% 75 20 63 C3 45Fe-10Pt-10Er-10Y-25GaN 98.75% 70 19 58 C4 79Fe-8Pt-6V-7BN 75.98% 2 28 106 C5 54Fe-11Pt-3Sc-12ZrN-20MnN 86.71% 4 29 112 C6 71Fe-2Pt-1Ir-4Ho-14AlN-8C 96.85% 5 32 123 C7 29Fe-22Pt-3Nb-10BN-11AlN-10C-15TaC 95.67% 61 20 64 C8 27Fe-38Pt-5B-6Mn-9BN-15WC 97.83% 70 twenty one 56 C9 19Fe-27Pt-3Zr-6Ir-10FeN-15ScN-20SiC 97.24% 67 twenty two 59 C10 59Fe-15Pt-1Er-15ZrN-10TiC 96.94% 32 25 93 C11 15Fe-23Pt-6Y-8Ho-10TaN-13GaN-5C-20ZrC 97.02% 43 twenty two 86

Experimental Results Discussion

According to the preparation methods of each embodiment and the experimental results in Table 2, it can be seen that by at least simultaneously adopting (1) controlling the usage range of the first component raw material and the nitride raw material, (2) performing water washing and drying steps, and (3) undergoing hydrogen gas reduction and re-sintering, the obtained iron-platinum-based target can simultaneously have the following technical characteristics: (I) the first component content is greater than or equal to 2 at% and less than or equal to 12 at%, (II) the nitride content is greater than or equal to 8 at% and less than or equal to 30 at%, (III) the calcium content in the iron-platinum-based target is less than 20 ppm, (IV) the oxygen content in the iron-platinum-based target is less than 1000 ppm, and (V) the relative density of the iron-platinum-based target is greater than 98%. On the other hand, the comparative examples do not simultaneously adopt the aforementioned technical means (1) to (3), so the iron platinum-based targets of comparative examples 1 to 11 also fail to simultaneously possess the aforementioned technical features (I) to (V). Therefore, compared with comparative examples 1 to 11, the iron platinum-based targets of embodiments 1 to 20 can extend the rust spot appearance time of the iron platinum-based targets of embodiments 1 to 20 to more than 75 hours under the same high temperature and high humidity environment; it can be seen that the technical means provided by the present invention can effectively enhance the antioxidant capacity.

In addition, it can be seen from the experimental results in Table 2 that the Ra of the sputtered films obtained by sputtering the FePt-based targets of Examples 1 to 20 are all less than 20 nm and the Rz are all less than 50 nm, indicating that the obtained sputtered films have a surface with small surface roughness.

Further referring to the combination of Example 1 and Comparative Example 1, although the iron platinum-based targets of Example 1 and Comparative Example 1 have the same main components, i.e., both are expressed as 46Fe-25Pt-4Ru-1B-24AlN, however, since Comparative Example 1 does not perform the water washing and drying steps in sequence, the calcium content of the iron platinum-based target obtained is as high as 211.7 ppm. It can be proved that the water washing step can indeed reduce the calcium content of the raw material mixture, so that the calcium content of the raw material mixture after drying can be controlled within the range of less than 20 ppm; in addition, since Comparative Example 1 does not perform the hydrogen reduction step, the oxygen content of the iron platinum-based target obtained is as high as 2001 ppm, which proves that the oxygen content of the reduced material can be reduced through the hydrogen reduction process, so that the oxygen content of the prepared FePt target can be controlled within the range of less than 1000 ppm. Therefore, the FePt target of Example 1 is far superior to the FePt target of Comparative Example 1 (relative density is 87.65%; rust spot appearance time is 5 hours) in terms of relative density (99.24%) and delayed oxidation phenomenon (172 hours). Furthermore, the surface roughness of the sputtered film formed by sputtering the FePt-based target in Example 1 (Ra is 6 nm; Rz is 24 nm) is also significantly smaller than that of the sputtered film formed by sputtering the FePt-based target in Comparative Example 1 (Ra is 23 nm; Rz is 87 nm). It can be seen that by controlling the technical characteristics of the FePt-based target in a specific range, the oxidation resistance of the FePt-based target is indeed improved, and the sputtered film formed by sputtering can have a lower surface roughness.

Also refer to the groups of Comparative Examples 6 and 7. Although the iron-platinum-based targets of Comparative Examples 6 and 7 have the first component and nitride content ranges that meet the definition of the present invention, because the preparation processes of Comparative Examples 6 and 7 did not sequentially perform water washing, drying, hydrogen reduction and other steps, it is impossible to control their calcium content (less than 20 ppm) and oxygen content (less than 1000 ppm) and relative density (less than 98%), resulting in the rust spots of the iron-platinum-based targets of Comparative Examples 6 and 7 appearing for a significantly shorter time, indicating that their antioxidant capacity is not good enough. Furthermore, the sputtered films formed by sputtering the FePt-based targets in Comparative Examples 6 and 7 have a relatively large surface roughness, indicating that the surface flatness thereof is not good.

Further referring to the groups of Comparative Examples 8 and 9, the content of the first component, the content of the nitride and the content of calcium in the iron-platinum-based target of Comparative Example 8 are all within the ranges defined by the present invention. However, since the preparation process of the iron-platinum-based target of Comparative Example 8 did not undergo a hydrogen reduction process, its oxygen content is slightly higher than the specific range of less than 1000 ppm defined by the present invention and the relative density of the iron-platinum-based target is less than 98% (97.83%), resulting in a shorter rust spot appearance time (70 hours) for the iron-platinum-based target of Comparative Example 8. Therefore, it can be seen that the iron-platinum-based target of Comparative Example 8 also cannot have better antioxidant ability. In addition, the content of the first component, the content of the nitride, and the content of oxygen in the iron-platinum-based target of Comparative Example 9 are all within the ranges specified by the present invention. However, since the iron-platinum-based target of Comparative Example 9 did not undergo a water washing process to control the calcium content during its preparation, its calcium content was slightly higher than the specific range of less than 20 ppm specified by the present invention. Furthermore, the iron-platinum-based target of Comparative Example 9 did not control its relative density, resulting in the appearance time of its rust spots being 67 hours. Therefore, it can be seen that the iron-platinum-based target of Comparative Example 9 also cannot have better antioxidant ability.

Further referring to the groups of Comparative Examples 2 and 3, the iron-platinum-based target of Comparative Example 2 has too low a content of the first component and too high a content of nitride. Therefore, even though the preparation process of Comparative Example 2 has undergone water washing and drying steps, it is still impossible to reduce the calcium content of the iron-platinum-based target to less than 20 ppm, resulting in the sputtered film formed by sputtering the iron-platinum-based target of Comparative Example 2 still having a relatively large surface roughness (Ra is 20 nm; Rz is 63 nm). Since the content of the first component in the iron-platinum-based target of Comparative Example 3 is too high, even if the preparation process of Comparative Example 3 has undergone a hydrogen reduction step, the oxygen content of the iron-platinum-based target cannot be reduced to less than 1000 ppm, resulting in a lower antioxidant capacity of the iron-platinum-based target of Comparative Example 3, and the sputtered film formed by sputtering the iron-platinum-based target of Comparative Example 3 still has a relatively large surface roughness (Rz is 58 nm).

In addition, looking at the analysis results in Table 2, the iron-platinum-based targets of Examples 1 to 3, 5, 6, 8 to 13, 15 to 17, 19, and 20 have a longer time for rust spots to appear (more than 109 hours) because their oxygen content is less than 625 ppm; even more, the iron-platinum-based targets of Examples 1, 3, 5, 6, 8, 12, 13, 15 to 17, and 20 have a longer time for rust spots to appear (more than 120 hours) because their oxygen content is less than 510 ppm.

In summary, the invention can improve the anti-oxidation ability of the FePt-based target by properly controlling the content and relative density of the first component, nitride, calcium and oxygen of the FePt-based target, and the sputtered film formed by the sputtering has the advantage of low surface roughness. Therefore, the FePt-based target provided by the invention can not only improve the film quality and yield of the magnetic recording layer formed by sputtering, but also avoid the problem of rusting caused by oxidation due to improper storage, further improving its commercial value.

The above-mentioned embodiments are only given for the convenience of explanation, but the embodiments are not intended to limit the scope of the patent application of this creation; any other changes, modifications, etc. that do not deviate from the disclosed content of this creation should be included in the patent scope covered by this creation.

without.

Figure 1 is an image of the iron-platinum-based target material of Example 1 after 172 hours of anti-oxidation test, magnified 100 times by an optical microscope. Figure 2 is an image of the iron-platinum-based target material of Comparative Example 4 after 2 hours of anti-oxidation test, magnified 100 times by an optical microscope

without.

Claims (12)

An iron-platinum-based target material comprises iron, platinum, a first component and a nitride; wherein the first component is selected from the group consisting of ruthenium, manganese, boron, rhodium, iridium, niobium, arsenic, yttrium, tantalum, beryl, vanadium, zirconium and combinations thereof; wherein, based on the total number of atoms in the entire iron-platinum-based target material, the content of the first component is greater than or equal to 2 atomic percent and less than or equal to 12 atomic percent, and the content of the nitride is greater than or equal to 8 atomic percent and less than or equal to 30 atomic percent; the calcium content in the iron-platinum-based target material is less than 20 parts per million, and the oxygen content in the iron-platinum-based target material is less than 1000 parts per million; wherein the relative density of the iron-platinum-based target material is greater than 98%. The iron-platinum-based target as described in claim 1, wherein the nitride is selected from the group consisting of boron nitride, aluminum nitride, vanadium nitride, nirconium nitride, manganese nitride, titanium nitride, iron nitride, gallium nitride, nickel nitride, zirconium nitride, niobium nitride, silicon nitride, einsteinium nitride, tantalum nitride, molybdenum nitride, cobalt nitride, chromium nitride and combinations thereof. The iron-platinum-based target as described in claim 1, wherein the iron-platinum-based target further comprises carbon or carbide. The iron-platinum-based target as described in claim 3, wherein the carbide is selected from the group consisting of tungsten carbide, titanium carbide, niobium carbide, tantalum carbide, chromium carbide, silicon carbide, zirconium carbide, boron carbide, vanadium carbide, arsenic carbide, titanium carbide nitrogen and combinations thereof. The iron-platinum-based target as described in claim 3, wherein, based on the total number of atoms of the entire iron-platinum-based target, the total content of the carbon and the carbide is greater than or equal to 10 atomic percent and less than or equal to 20 atomic percent. An iron-platinum-based target as described in any one of claims 1 to 5, wherein the content of platinum is greater than or equal to 3 atomic percent and less than or equal to 30 atomic percent based on the total number of atoms in the entire iron-platinum-based target. An iron-platinum-based target as described in any one of claims 1 to 5, wherein the iron content is greater than or equal to 8 atomic percent and less than or equal to 77 atomic percent based on the total number of atoms in the entire iron-platinum-based target. A method for preparing an iron-platinum-based target material, comprising the following steps: Step (a): mixing and grinding an iron raw material, a platinum raw material, a first component raw material and a nitride raw material to obtain a raw material mixture; wherein the first component is selected from the group consisting of ruthenium, manganese, boron, rhodium, iridium, niobium, arsenic, yttrium, beryl, vanadium, zirconium and combinations thereof; based on the total number of atoms in the raw material mixture as a whole, the addition amount of the first component raw material is greater than or equal to 2 atomic percent and less than or equal to 12 atomic percent, and the addition amount of the nitride raw material is greater than or equal to 8 atomic percent and less than or equal to 30 atomic percent; Step (b): placing the raw material mixture in water for agitation and washing process to obtain a washed raw material mixture; wherein the temperature of the water is greater than or equal to 55°C and less than or equal to 65°C; Step (c): subjecting the washed raw material mixture to a drying process to obtain a dried raw material mixture; Step (d): subjecting the dried raw material mixture to a hydrogen reduction process to obtain a reduced material; and Step (e): sintering the reduced material to obtain the iron-platinum-based target; wherein, the calcium content in the iron-platinum-based target is less than 20 parts per million, and the oxygen content in the iron-platinum-based target is less than 1000 parts per million; the relative density of the iron-platinum-based target is greater than 98%. A method for producing an iron-platinum-based target as described in claim 8, wherein, in the step (b), the ratio of the weight of the raw material mixture to the volume of the water is greater than or equal to 90 g/L and less than or equal to 110 g/L. A method for producing an iron-platinum-based target as described in claim 8, wherein, in the step (d), the duration of the hydrogen reduction process is greater than or equal to 1 hour and less than or equal to 3 hours; and the reduction temperature is greater than or equal to 550°C and less than or equal to 900°C. A method for manufacturing an iron-platinum-based target as described in claim 8, wherein, in the step (e), the sintering temperature is greater than or equal to 700°C and less than or equal to 1200°C, and the sintering pressure is greater than or equal to 220 bar and less than or equal to 1850 bar. A method for producing an iron-platinum-based target as described in any one of claims 8 to 11, wherein the step (a) further includes a carbon raw material or a carbide raw material.