TW202039894A - Fe-pt based sputtering target and method for producing the same - Google Patents

Abstract

Provided is a Fe-Pt based sputtering target and a method for producing the same. The Fe-Pt based sputtering target includes iron, platinum, and carbon. Based on the total amount of the Fe-Pt based sputtering target, the amount of the carbon is equal to or larger than 15 at% and equal to or smaller than 45 at%. In addition, a carbon phase in a metallography of the Fe-Pt based sputtering target has an average size smaller than 2 μm, and the carbon phase has an average aspect ratio smaller than 3. By controlling the carbon content of the Fe-Pt based sputtering target and limiting the type of the carbon phase in the metallography, the Fe-Pt based sputtering target can suppress black carbon particles generated and the occurrence of abnormal discharges during sputtering, and mitigate the problem of particulate contamination of a magnetic recording layer formed by the Fe-Pt based sputtering target. Therefore, the quality and yield of the magnetic recording layer formed by the Fe-Pt based sputtering target can be improved.

Description

Fe-platinum-based target material and manufacturing method thereof

This creation is about an iron-platinum-based target, especially an iron-platinum-based target suitable for magnetic recording media; in addition, this creation is about a manufacturing method of an iron-platinum-based target.

Magnetic recording refers to the use of the hysteresis characteristics of magnetic materials to store information on a recording medium. According to the direction of magnetization of the magnetic head, the magnetic recording media in the prior art can be divided into a horizontal magnetic recording medium (LMR) and a vertical magnetic recording medium (PMR). As a storage medium for information storage, high stability is the primary requirement. Not only that, in recent years, with consumers’ demand for portable recording media, the rise of big data, and the production of huge amounts of information, people’s demand for magnetic recording media’s information storage capacity has increased. Therefore, how to improve The recording density of magnetic recording media has always been the focus of research in related fields. However, since the magnetic recording density of horizontal magnetic recording media is now approaching the physical limit, vertical magnetic recording media that can delay the superparamagnetic limit and achieve higher recording density have become the technical direction to solve the problem.

In addition, perpendicular magnetic recording media can also be combined with heat-assisted magnetic recording (HAMR) technology. The thermally assisted magnetic recording system acts on the magnetic particles of the recording bit by means of thermal energy while writing the magnetic field. By increasing the temperature of the magnetic particles above the Curie temperature, the magnetic force of the magnetic particles The coercivity is temporarily reduced, and the recording density of the magnetic recording medium can be increased.

Generally speaking, the layered structure of a vertical magnetic recording medium includes a substrate, an adhesion layer, a soft magnetic layer, a seed layer, an intermediate layer, a magnetic recording layer, a cover layer, and a lubricating layer from bottom to top.

Because the heat-assisted magnetic recording technology will repeatedly focus and heat in the same area, it is necessary to use a highly stable magnetic composite material as the magnetic recording layer. Most of the heat-assisted magnetic recording layers in the prior art use iron-platinum-based alloy systems as the magnetic recording layer. The main component, and additional non-magnetic components such as carbon are added to the Fe-Pt-based alloy system to form a barrier between the grains of the Fe-Pt-based alloy and reduce the magnetic coupling effect.

However, the aforementioned magnetic recording layer is usually formed by a sputtering method. If a separate iron target, a platinum target and a carbon target are used to form the magnetic recording layer by sputtering together, it is not only difficult to control the composition of the magnetic recording layer, but also causes an increase in the cost of the device.

Although there have been attempts in the prior art to sinter carbon raw materials and powders of iron, platinum and other raw materials into sputtering targets, on the one hand, carbon is easy to accumulate. Therefore, when the carbon raw materials are added in a high proportion, the target material It is difficult to mix the ingredients uniformly; on the other hand, during the sintering process, carbon may solid dissolve into the iron phase to form iron-carbon compounds. The aforementioned conditions all lead to the problem of a large amount of carbon precipitation on the surface of the target material, which may cause abnormal discharges to be easily formed in the subsequent sputtering process, and a large number of particles may fall to the magnetic recording layer formed by the sputtering, thereby affecting The quality and yield of the film to the magnetic recording layer.

In view of the shortcomings faced by the prior art, the purpose of this creation is to reduce the amount of carbon deposited on the surface of the target, reduce the frequency of abnormal discharges in the subsequent sputtering process, and reduce the problem of particle pollution, thereby improving the formation of sputtering The quality and yield of the magnetic recording layer.

To achieve the foregoing purpose, this creation provides an iron-platinum-based target material, which contains iron (Fe), platinum (Pt), and carbon (C); among them, based on the total number of atoms of the overall iron-platinum-based target material, the carbon The content is greater than or equal to 15 atomic percentage (at%) and less than or equal to 45 at%; in the metallographic phase of the iron-platinum-based target, the average size of the carbon phase is less than or equal to 2 microns (μm), and the carbon phase The average axial length ratio is less than 3.

According to this creation, by adjusting the carbon content in the iron-platinum-based target, the average size range of the carbon phase and the average axial length ratio range of the carbon phase, it helps to improve the uniformity of the phase composition of the overall iron-platinum-based target , Thereby effectively reducing the amount of carbon precipitated on the surface of the iron-platinum-based target material, ensuring that the frequency of abnormal discharges is reduced in the sputtering process of subsequent applications, and the problem of particle pollution is reduced.

According to this creation, the size of each carbon phase refers to the maximum length of each black phase in the metallographic microstructure through the center point; and the average value of the aforementioned multiple sets of data is the average size of the carbon phase.

According to this creation, the axial length ratio of each carbon phase is based on the maximum length of each black phase passing through the center point in the metallographic microstructure as its length, and the minimum length of each black phase passing through the center point in the metallographic microstructure as its width, and the ratio of length to width is Is the axis length ratio; taking the average of the aforementioned multiple sets of data is the average axis length ratio of the carbon phase.

Preferably, based on the total number of atoms of the whole iron-platinum-based target, the iron content is greater than or equal to 20 at% and less than or equal to 70 at%.

Preferably, based on the total number of atoms of the whole iron-platinum-based target, the platinum content is greater than or equal to 10 at% and less than or equal to 40 at%; more preferably, the platinum content is greater than or equal to 14 at% and Less than or equal to 40 at%; even better, the platinum content is greater than or equal to 15 at% and less than or equal to 38 at%.

According to this creation, the type of carbon in the iron-platinum-based target can be diamond carbon with a three-dimensional tetrahedral structure, graphitic carbon with a two-dimensional planar structure, carbon nanotubes with a one-dimensional structure, or a combination thereof, but is not limited to this. Preferably, the carbon type is diamond carbon.

In some embodiments, in order to make the film formed by the sputtering of the iron-platinum-based target material have better barrier properties and be more conducive to use as a magnetic recording layer, the iron-platinum-based target material may further include boron nitride (BN). Preferably, the content of boron nitride in the whole iron-platinum-based target is greater than 0 at% and less than or equal to 10 at%.

In other embodiments, in order to make the magnetic recording layer sputtered from the iron-platinum-based target material have better thermal stability, and to make the magnetic recording layer have a lower heat transfer temperature, the iron-platinum-based target The material may further include copper (Cu), silver (Ag), or a combination thereof, but is not limited to this. Preferably, the content of copper in the overall iron-platinum-based target is greater than or equal to 0.5 at% and less than or equal to 2 at%; preferably, the content of silver in the overall iron-platinum-based target is greater than or equal to 0.5 at% And less than or equal to 2 at%.

According to this creation, X-ray diffraction analysis (X-ray diffraction, XRD) can be performed on the sputtering surface of the iron-platinum-based target. Preferably, in the X-ray diffraction pattern of the iron-platinum-based target, the full width at half maximum (FWHM) of the (111) crystal plane characteristic peak of the iron-platinum alloy is less than 0.3°. Accordingly, by controlling the half-height width of the characteristic peak of the (111) crystal plane of the iron-platinum alloy in the iron-platinum-based target material, the amount of carbon deposited on the surface of the iron-platinum-based target material can be further reduced.

Preferably, the iron-platinum-based target material can be subsequently applied to DC sputtering, radio frequency sputtering, or magnetron sputtering, but it is not limited to this.

In addition, this creation also provides a method for manufacturing an iron-platinum-based target, which includes the following steps: Step (A): Grind the carbon raw material by a high-energy mechanical grinding method to obtain a ground carbon powder with an average particle size of 0.3 μm To 3 μm; step (B): mixing the ground carbon powder, iron raw material, and platinum raw material and mechanically alloying them to obtain an iron-platinum-based alloy powder; and step (C): including the hot-pressure sintering method The iron-platinum-based alloy powder is sintered to obtain an iron-platinum-based target; wherein, based on the total number of atoms of the overall iron-platinum-based target, the carbon content is greater than or equal to 15 at% and less than or equal to 45 at %; In the metallographic phase of the iron-platinum-based target, the average size of the carbon phase is less than or equal to 2 μm, and the average axial length ratio of the carbon phase is less than 3.

By means of high-energy mechanical grinding, the carbon raw material is pre-treated, and all the raw materials are mixed and mechanically alloyed, which helps to obtain a specific average size range and average axis when forming iron-platinum-based targets. The carbon phase in the length ratio range effectively reduces the amount of carbon deposited on the surface of the Fe-Pt-based target.

According to this creation, the high-energy mechanical grinding method in this step (A) is high-energy ball milling. The grinding balls used can be stainless steel beads or zirconia beads (ZrO ₂ ), and the particle size can be from 2 millimeters (mm) to 10 mm, but not limited to this. Preferably, the grinding time in the aforementioned high-energy mechanical grinding step is 1 hour to 10 hours.

According to this creation, in this step (A), the type of carbon raw material can be diamond carbon with three-dimensional structure, graphitic carbon with two-dimensional planar structure, carbon nanotube with one-dimensional structure, or a combination thereof, but is not limited to this . Preferably, the type of carbon raw material is diamond carbon. In order to reduce the drop of particles or abnormal discharge caused by the difference in conductivity between the base phase (ie, the iron-platinum phase) and the dopant (such as the carbon phase) during the sputtering of the iron-platinum-based target material, the average particle size of the carbon raw material It is 2 μm to 10 μm. Preferably, when the type of the carbon raw material is diamond carbon, the average particle size is 2 μm to 5 μm; when the type of the carbon raw material is graphitic carbon, the average particle size is 2 μm to 10 μm.

According to this creation, in this step (B), the iron raw material can be iron metal with a purity of more than 99%, an iron alloy with an iron content of more than 50% by weight (wt%), or a combination thereof, but it is not limited to this. Preferably, the average particle size of the iron raw material is 20 μm to 80 μm. By selecting an iron raw material with an average particle size in the aforementioned range, the residual amount of oxygen in the iron-platinum-based target can be reduced.

According to this creation, in this step (B), the platinum raw material can be platinum metal with a purity of more than 99%, a platinum alloy with a platinum content of more than 50 wt%, or a combination thereof, but it is not limited to this. Preferably, the average particle size of the platinum raw material is 1 μm to 10 μm, which makes it easier for platinum to diffuse in the iron phase.

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

According to this creation, this step (B) further includes boron nitride. Preferably, the average particle size of the boron nitride is less than 3.0 μm.

According to this creation, this step (B) may further include copper raw materials with an average particle size of 50 μm to 150 μm, silver raw materials with an average particle size of 5 μm to 10 μm, or a combination thereof. Specifically, the copper raw material may be copper metal with a purity of 99% or more, a platinum alloy with a copper content of 50 wt% or more, or a combination thereof, but it is not limited to this. The silver raw material may be silver metal with a purity of 99% or more, a silver alloy with a silver content of 50 wt% or more, or a combination thereof, but it is not limited to this.

According to this creation, in this step (B), the ground carbon powder, iron raw material, platinum raw material and other raw materials can be added and mixed in any order, and can be added simultaneously or sequentially, adding the entire amount of these ingredients at once, or These ingredients are added in equal amounts in portions, dispersed until uniformly dispersed, and then mechanically alloyed together (for example, high-energy mechanical grinding) to obtain iron-platinum-based alloy powder.

In some embodiments, step (B) includes: step (B1): mixing the ground carbon powder, iron raw material, and platinum raw material to obtain a mixture; and step (B2): performing mechanical alloying on the mixture to obtain The iron-platinum-based alloy powder. In other embodiments, the mixture of step (B1) may further include boron nitride, silver raw material, copper raw material, or a combination thereof.

Specifically, the mechanical alloying in this step (B2) adopts a high-energy ball milling method, wherein the grinding balls used can be stainless steel beads or zirconia beads (ZrO ₂ ), and the particle size can be 2 mm to 10 mm , But not limited to this. Preferably, the grinding time in the aforementioned mechanical alloying step is 1 hour to 10 hours.

Preferably, in the iron-platinum-based target obtained in step (C), the content of iron in the whole iron-platinum-based target is greater than or equal to 20 at% and less than or equal to 70 at%; preferably, The total number of atoms of the whole iron-platinum-based target is the benchmark, and the platinum content is greater than or equal to 10 at% and less than or equal to 40 at%; more preferably, the platinum content is greater than or equal to 14 at% and less than or equal to 40 at %; Even better, the platinum content is greater than or equal to 15 at% and less than or equal to 38 at%.

Specifically, the sintering method in this step (C) may be the hot pressure equalization sintering method alone, or a combination of the hot equalization pressure sintering method and spark plasma sintering (SPS).

Preferably, in this step (C), when HIP sintering is used alone, the sintering temperature is 500°C to 1300°C, and the sintering pressure is 50 megapascals (MPa) to 200 MPa. When combining HIP and SPS sintering, the sintering temperature of HIP is 500°C to 1300°C, the sintering pressure is 50 MPa to 200 MPa; the sintering temperature of SPS is 600°C to 1300°C, and the sintering pressure is 20 MPa to 100 MPa.

Preferably, when HIP sintering is used alone, it lasts for 1 hour to 7 hours. When combining HIP and SPS sintering, HIP continues sintering for 1 hour to 3 hours, and SPS continues sintering for 0.1 hour to 3 hours.

In some embodiments, this step (C) can be carried out in a staged sintering step at different temperatures. For example, when HIP sintering is used alone, it can be sintered at a high temperature of 800°C to 1300°C for 0.5 hours to 5 hours, and then cooled to 500°C to 800°C for 0.5 hours to 2 hours. In some other embodiments, when combining HIP and SPS for sintering, first continue sintering with HIP for 1 hour to 3 hours, and then continue sintering with SPS at 800°C to 1300°C for 0.1 hour to 1 hour, and then reduce to 600 °C to 800°C continuous sintering for 0.5 hours to 2 hours.

In order to verify the influence of the composition of raw materials, pre-treatment and/or mixing sequence, and sintering parameters on the iron-platinum-based target material, several iron-platinum-based target materials are listed below as examples to explain in detail the implementation of this creation and the technology Those with ordinary knowledge in the field can easily understand the advantages and effects of this creation through the content of this manual, and make various modifications and changes without departing from the spirit of this creation to implement or apply the content of this creation.

Models of analytical instruments used in the following examples: 1. Scanning electron microscope: Hitachi SE-3400; 2. Energy dispersion spectrometer: HORIBA EMAX 450; 3. X-ray diffractometer: Multipurpose X-ray diffraction system; 4. Inductively coupled plasma emission spectrometer: Perkinelmer Avio 500.

The raw materials used in the following examples: 1. Carbon raw material: diamond carbon powder with an average particle size of 3 μm; 2. Carbon raw material: graphite carbon powder with an average particle size of 10 μm; 3. Iron raw material: iron metal powder with an average particle size of 60 μm; 4. Platinum raw material: platinum metal powder with an average particle size of 7 μm; 5. Boron nitride: average particle size is 2 μm; 6. Silver raw material: silver metal powder with an average particle size of 8 μm; 7. Copper raw material: copper metal powder with an average particle size of 80 μm.

Example 1 : Fe-platinum based target

Place the diamond carbon powder and multiple grinding balls with a diameter of 5 mm in a ball milling tank and perform high-energy ball milling for 3 hours to obtain a ground diamond carbon powder with an average particle diameter of 0.5 μm. In addition, the ground diamond carbon powder, platinum metal powder, and iron metal powder are all sieved with a 400 mesh screen for use.

Then, based on the total number of atoms of the whole raw material, weigh 25 at% of ground diamond carbon powder, 30 at% of platinum metal powder, and 45 at% of iron metal powder, and then mix the aforementioned diamond carbon powder and platinum metal Powder and iron metal powder to obtain a mixture, and then subject the mixture to high-energy ball milling for 3 hours to obtain an iron platinum-based alloy powder.

Then, the iron-platinum-based alloy powder is uniformly filled in a mold, and the sintering temperature is 800°C, the sintering pressure is 150 MPa, and the hot equalization sintering method is continuously sintered for 3 hours. Finally, computer numerical control is used. , CNC) lathe processing to obtain the iron-platinum-based target with a diameter of 165 mm and a thickness of 4 mm.

Example 2 to 8 : Fe-platinum based target

The preparation methods used in Examples 2 to 8 are similar to the preparation method of the iron-platinum-based target material in Example 1. Examples 2 to 8 are based on the composition of each iron-platinum-based target as shown in Table 1 below. The iron raw material, platinum raw material, and ground carbon raw material are weighed and mixed to obtain the mixture, and then proceed as in Example 1. In the high-energy ball milling step, the sintering step was performed according to the sintering method and temperature shown in Table 1 below, and finally the iron-platinum-based targets of Example 2 to Example 8 were obtained.

The difference between the preparation methods of the iron-platinum-based target materials of Examples 1 to 8 is mainly to change the type of the selected carbon raw materials, the amount of each raw material, and the sintering method and sintering temperature used in the sintering step. Among them, the carbon raw material selected in Examples 2 and 5 is graphite carbon powder, and the carbon raw material selected in Examples 3, 4, 7 and 8 is the same as that of Example 1 diamond carbon powder.

In addition, in Example 3 and Example 8, the sintering step was completed by first sintering with SPS for 0.5 hours and then with HIP for 3 hours. The sintering temperature of the SPS and HIP is shown in Table 1 below.

Example 9 with 10 : Fe-platinum based target

Compared with the iron-platinum-based targets of Examples 1 to 8, the iron-platinum-based targets of Examples 9 and 10 not only use iron raw materials, platinum raw materials, and carbon raw materials, but also contain boron nitride. The preparation method used in Examples 9 and 10 is similar to the preparation method of the iron-platinum-based target material in Example 1. First, the diamond carbon powder is treated with the high-energy ball milling step as used in Example 1; in addition, the boron nitride Sieved with a 400 mesh screen for use; then, weigh the iron raw material, platinum raw material, and ground diamond carbon powder according to the composition of the iron-platinum-based target materials of Examples 9 and 10 shown in Table 1 below , And boron nitride, and mixed to obtain a mixture; the iron-platinum-based alloy powder is obtained by the high-energy ball milling step as used in the foregoing example 1; and then the iron-platinum-based alloy powder is obtained according to the sintering method and temperature shown in Table 1 below. The iron-platinum-based alloy powder was sintered for 3 hours; and finally processed by a CNC lathe to obtain an iron-platinum-based target with a diameter of 165 mm and a thickness of 4 mm. The main differences between the preparation methods of the iron-platinum-based targets of Example 1 and Examples 9 and 10 are the addition of boron nitride as the raw material, the change of the amount of each raw material, and the change of the sintering temperature.

Example 11 to 14 : Fe-platinum based target

Compared with the iron-platinum-based targets of Examples 1 to 8, the iron-platinum-based targets of Examples 11 to 14 not only use iron raw materials, platinum raw materials, and carbon raw materials, but also include silver raw materials or copper raw materials. The preparation method used in Examples 11 to 14 is similar to the preparation method of the iron-platinum-based target material in Example 1. First, the diamond carbon powder is treated with the high-energy ball milling step as used in Example 1; the silver material or copper material Sieved with a 140 mesh screen for use; then, weigh the iron raw material, platinum raw material, and ground diamond carbon powder according to the composition of the iron-platinum-based target materials of Examples 11 to 14 shown in Table 1 below , And silver raw materials (such as Examples 11 and 13) or copper raw materials (such as Examples 12 and 14), and mixed to obtain a mixture; then use the same high-energy ball milling step as in Example 1 to obtain the iron platinum-based Alloy powder; then sinter the iron-platinum-based alloy powder for 3 hours according to the sintering method and temperature shown in Table 1; and finally process it with a CNC lathe to obtain a disc-shaped iron-platinum-based with a diameter of 165 mm and a thickness of 4 mm Target. The main differences between the preparation methods of the iron-platinum-based targets of Example 1 and Examples 11 to 14 are the addition of silver or copper raw materials, changing the amount of each raw material, and changing the sintering temperature.

Comparative example 1 : Fe-platinum based target

The method used for the iron-platinum-based target of Comparative Example 1 is roughly the same as the preparation method of the iron-platinum-based target of Example 1, and the main difference lies in the content of the carbon raw material, the sintering method and the sintering temperature. The specific preparation method of this comparative example is as follows: the diamond carbon powder is processed by the high-energy ball milling step as used in the aforementioned example 1; and then weighed according to the composition of the iron-platinum-based target material of the comparative example 1 shown in Table 1 below The iron raw material, the platinum raw material, and the ground diamond carbon powder are mixed together to obtain a mixture; then, the iron-platinum-based alloy powder is obtained by the high-energy ball milling step as used in the foregoing example 1; and then the iron-platinum The base alloy powder was sintered by hot pressing (HP) at a sintering temperature of 1100°C for 3 hours; finally processed by a CNC lathe to obtain an iron-platinum base target with a diameter of 165 mm and a thickness of 4 mm. .

Comparative example 2 : Fe-platinum based target

The method used for the iron-platinum-based target of Comparative Example 2 is roughly the same as the method for preparing the iron-platinum-based target of Example 3. The main difference is that the carbon raw material of Comparative Example 2 does not undergo a high-energy ball milling step. The specific preparation method of this comparative example is as follows: According to the composition of Comparative Example 2 shown in Table 1 below, weigh the diamond carbon powder, platinum metal powder, and iron metal powder, and then combine the diamond carbon powder and platinum powder without high-energy ball milling. The metal powder and iron metal powder are sieved with a 400 mesh screen, mixed and subjected to high-energy ball milling for 3 hours to obtain an iron-platinum-based alloy powder. Then, the iron-platinum-based alloy powder was uniformly filled in a mold, and sintered with SPS at a sintering temperature of 800°C and a sintering pressure of 60 MPa for 0.5 hours; then, sintering at a sintering temperature of 1100°C and 150 The sintering pressure is MPa, and the HIP sintering is continued for 3 hours; finally, it is processed by a CNC lathe to obtain a round iron-platinum-based target with a diameter of 165 mm and a thickness of 4 mm.

Comparative example 3 : Fe-platinum based target

The preparation method of the iron-platinum-based target material of Comparative Example 3 is roughly the same as the preparation method of the iron-platinum-based target material of Example 5. The main difference lies in the content of carbon raw materials and the way of sintering, as well as the method of Comparative Example 3. The carbon raw material has not undergone a high-energy ball milling step. The specific preparation method of this comparative example is as follows: weigh graphite carbon powder, platinum metal powder, and iron metal powder according to the composition of Comparative Example 3 shown in Table 1 below, and then combine the graphite carbon powder and platinum powder without high-energy ball milling. The metal powder and iron metal powder are sieved with a 400 mesh screen, mixed and subjected to high-energy ball milling for 3 hours to obtain an iron-platinum-based alloy powder. Then, the iron-platinum-based alloy powder was uniformly filled in a mold, and then sintered in HP at a sintering temperature of 1100°C for 3 hours; finally processed by a CNC lathe to obtain a round cake with a diameter of 165 mm and a thickness of 4 mm Fe-platinum-based target material.

Comparative example 4 : Fe-platinum based target

The preparation method of the iron-platinum-based target material of Comparative Example 4 is roughly the same as the preparation method of the iron-platinum-based target material of Example 3. The main difference lies in the mixing ratio, mixing sequence and sintering temperature of the raw materials. The specific preparation method of this comparative example is as follows: the diamond carbon powder is processed by the high-energy ball milling step as used in the foregoing example 1; then the composition of the iron-platinum-based target material of the comparative example 4 shown in the following table 1 is first weighed. After grinding diamond carbon powder and iron metal powder and mixing them with high-energy ball milling for 3 hours, a powder containing iron-carbon compounds is obtained; then platinum metal powder is added and mixed uniformly. The sintering temperature is 800°C and 60 MPa. The sintering pressure is continuously sintered with SPS for 0.5 hours; then, the sintering temperature is 900°C, the sintering pressure is 150 MPa, and the HIP is sintered for 3 hours. Finally, a circle with a diameter of 165 mm and a thickness of 4 mm is obtained by CNC lathe processing. Pie-shaped iron-platinum-based target.

Comparative example 5 : Fe-platinum based target

The preparation method of the iron-platinum-based target material of Comparative Example 5 is approximately the same as the preparation method of the iron-platinum-based target material of Example 3. The main difference lies in the mixing ratio, mixing sequence and sintering temperature of the raw materials. The specific preparation method of this comparative example is as follows: the diamond carbon powder is processed by the high-energy ball milling step as used in the aforementioned example 1; then the composition of the iron-platinum-based target material of the comparative example 5 shown in the following table 1 is first weighed. The ground diamond carbon powder and platinum metal powder are mixed and subjected to high-energy ball milling for 3 hours to obtain a mixed powder; then iron metal powder is added and mixed uniformly. The sintering temperature is 800°C and the sintering pressure is 60 MPa. SPS continued sintering for 0.5 hours; then, sintering was continued for 3 hours with HIP at a sintering temperature of 900°C and a sintering pressure of 150 MPa; and finally processed by a CNC lathe to obtain a round cake-shaped iron with a diameter of 165 mm and a thickness of 4 mm Platinum-based target.

Comparative example 6 : Fe-platinum based target

The preparation method of the iron-platinum-based target material of Comparative Example 6 is roughly the same as the preparation method of the iron-platinum-based target material of Example 2. The main difference is that the carbon raw material of Comparative Example 6 is not subjected to the high-energy ball milling step, and the raw materials The order of mixing is different. The specific preparation method of this comparative example is as follows: According to the composition of the iron-platinum-based target material of Comparative Example 6 shown in Table 1 below, first weigh the graphite carbon powder and iron metal powder that have not been high-energy ball milled and mix them with high-energy ball milling 3 After hours, a powder containing iron-carbon compounds is obtained; then platinum metal powder is added and mixed uniformly, and the sintering temperature is 800°C and the sintering pressure is 60 MPa, and the sintering is continued for 0.5 hours with SPS; then, the temperature is 900° The sintering temperature is C and the sintering pressure is 150 MPa, and HIP is used for continuous sintering for 3 hours. Finally, it is processed by a CNC lathe to obtain a circular iron-platinum-based target with a diameter of 165 mm and a thickness of 4 mm.

Comparative example 7 : Fe-platinum based target

The preparation method of the iron-platinum-based target material of Comparative Example 7 is roughly the same as the preparation method of the iron-platinum-based target material of Example 2. The main difference is that the carbon raw material of Comparative Example 7 is not subjected to the high-energy ball milling step, and the raw materials The order of mixing is different. The specific preparation method of this comparative example is as follows: According to the composition of the iron-platinum-based target of Comparative Example 7 as shown in Table 1 below, first weigh the graphite carbon powder and platinum metal powder that have not been high-energy ball milled and mix them with high-energy ball milling 3 After hours, get a mixed powder; then add iron metal powder and mix evenly, first sinter with SPS at 800°C sintering temperature and 60 MPa sintering pressure for 0.5 hours; then, at 900°C sintering temperature , 150 MPa sintering pressure, continuous sintering with HIP for 3 hours; finally processed by CNC lathe to obtain a circular iron-platinum-based target with a diameter of 165 mm and a thickness of 4 mm.

Comparative example 8 : Fe-platinum based target

The preparation method of the iron-platinum-based target material of Comparative Example 8 is similar to the preparation method of the iron-platinum-based target material of Example 1. In Comparative Example 8, iron raw materials, platinum raw materials, and ground diamond carbon powder were weighed according to the composition shown in Table 1 below, and mixed together to obtain a mixture. The main difference between the preparation methods of the iron-platinum-based target material of Example 1 and Comparative Example 8: Comparative Example 8 uses 60 at% of the total number of atoms of the raw material after grinding diamond carbon powder, and Comparative Example 8 The sintering temperature is 1000°C.

Comparative example 9 : Fe-platinum based target

The preparation method of the iron-platinum-based target of Comparative Example 9 is roughly the same as the preparation method of the iron-platinum-based target of Example 5. The main difference is that the carbon raw material of Comparative Example 7 is not subjected to the high-energy ball milling step, and the raw materials The mixing ratio is different. The specific preparation method of this comparative example is as follows: weigh graphite carbon powder, platinum metal powder, and iron metal powder according to the composition of Comparative Example 9 shown in Table 1 below, and then combine the graphite carbon powder, platinum The metal powder and the iron metal powder are sieved with a 400 mesh screen and then mixed to obtain a mixture; after high-energy ball milling for 3 hours, an iron-platinum-based alloy powder is obtained. Then, the iron-platinum-based alloy powder was uniformly filled in a mold, and then sintered with HIP at a sintering temperature of 1100°C for 3 hours; finally processed by a CNC lathe to obtain a round cake with a diameter of 165 mm and a thickness of 4 mm Fe-platinum-based target material.

analysis 1 : Metallographic microstructure of Fe-Pt-based target

analysis 1-1 : Observe the distribution and morphology of each phase in the metallography

Samples were taken at the target site with a radius of 0.5 from the center of the iron-platinum-based targets of Examples 1 to 14 and Comparative Examples 1 to 9, and a 10 mm×10 mm test piece was obtained by wire cutting.

SEM was used to photograph the metallographic microstructure of the test pieces of the iron-platinum-based targets of Examples 1 to 14 and Comparative Examples 1 to 9 at an appropriate magnification. In this specification, the iron-platinum-based target material (as in Example 1) made by using diamond carbon powder as the carbon raw material and the iron-platinum-based target material (as in Example 6) made by using graphite carbon powder as the carbon material are used. Illustratively, the metallographic microstructures of the iron-platinum-based targets of Example 1 and Example 6 are shown in the SEM photos of Figures 1 and 2, respectively; in addition, the iron-platinum-based targets of Comparative Examples 1, 2, 4, and 5 The metallographic microstructures are shown in SEM photos in Figure 3 to Figure 6, respectively. In the experiment, the metallographic composition of Example 2 was analyzed with energy dispersive spectrometers (EDS), and the composition of the black phase was 100 at% C, and the composition of the gray phase was 46.21 at% Fe-53.79 at% Pt. The overall phase composition of the test piece is 41.92 at%Fe-35.55 at%Pt-22.53 at%C.

From the comparison of Fig. 1, Fig. 2 and Fig. 3 to Fig. 6, it can be seen that no matter which carbon raw material is used to prepare iron-platinum-based target, the carbon material is subjected to high-energy ball milling in advance, and then the iron-platinum is sintered by hot equalization sintering. Base alloy powder, the black phase in the iron-platinum-based targets of Example 1 and Example 6 all present a finer dot-like uniform distribution pattern. Conversely, whether it is the iron-platinum-based target material of Comparative Example 1 sintered by the hot press molding method, or the iron-platinum-based target material of Comparative Example 2 where the carbon raw material is not processed by the high-energy ball milling step, the carbon phase contained therein It presents a larger form. In addition, the iron-platinum-based targets of Comparative Examples 4 and 5 in which the carbon raw material, the iron raw material and the platinum raw material are not simultaneously subjected to the high-energy ball milling step, the carbon phase contained therein is obviously unevenly distributed; furthermore, first Comparative Example 4 where the carbon raw material and the iron raw material are subjected to the high-energy ball milling step, because the iron raw material and the carbon raw material will react first to produce more iron-carbon compounds, so that a large number of holes are formed in the iron-platinum-based target material that is finally sintered; and In Comparative Example 5, where the carbon raw material and the platinum raw material were first subjected to high-energy ball milling, although the sintered iron-platinum-based target material has significantly fewer pores, there are long and narrow black carbide phases with a larger size.

analysis 1-2 : The average size of the carbon phase in the metallographic phase

The image analysis software Image-Pro Plus was used to analyze the metallography of the test pieces of the iron-platinum-based targets of Examples 1 to 14 and Comparative Examples 1 to 9, respectively. The metallographic system 1 was taken by SEM at a magnification of 5000 times Metallographic. Randomly shoot 3 different areas in the same test piece to obtain three metallographic diagrams, and then directly use the image analysis software to analyze the dimensions of each carbon phase in the three metallographic diagrams, and finally use the software to calculate the three metallographic diagrams The average size of the carbon phase represents the average size of the carbon phase of the iron-platinum-based target, and the results are recorded in Table 1 below.

analysis 1-3 : Axial length ratio of carbon phase in metallography

The image analysis software Image-Pro Plus was used to analyze the metallography of the test pieces of the iron-platinum-based targets of Examples 1 to 14 and Comparative Examples 1 to 9, respectively. The metallographic system 1 was taken by SEM at a magnification of 5000 times Metallographic. Randomly shoot 3 different areas in the same test piece to obtain three metallographic images, and then directly use the built-in "Aspect" function in the image analysis software to analyze the axis length of each carbon phase in the three metallographic images Finally, use software to calculate the average axial length ratio of the carbon phases in the three metallographic diagrams, which represents the average axial length ratio of the carbon phase of the iron-platinum-based target, and record the results in Table 1 below.

Minute Analyze 2 : Fe-platinum-based target FePt Relative (111) Characteristic peak FWHM

The test pieces of the iron-platinum-based targets of Examples 1 to 14 and Comparative Examples 1 to 9 where the metallography has been observed are respectively marked with sandpaper numbers #60, #120, #240, #320, #600, #1000, # 1500, #2000 and #4000 are ground in order; when grinding, it is necessary to rotate 90 cross grinding to remove the grinding marks, until the grinding to #4000 sandpaper, that is to complete the iron-platinum-based targets of Examples 1 to 14 and Comparative Examples 1 to 9 XRD test piece. Next, under the condition that the step size is 0.04° and the 2θ is between 20° and 100°, the crystal phase structure of the iron-platinum-based target materials of Examples 1-14 and Comparative Examples 1-9 are analyzed by XRD measurement. In the X-ray diffraction spectrum, the intensity of the characteristic peaks corresponding to each crystal plane will have a positive correlation with the crystal orientation of the crystal grains on the surface of the test piece. Then, in the XRD pattern obtained by software Jade analysis, the FWHM of the characteristic peak of the (111) crystal plane of the FePt phase was analyzed, and the results were recorded in Table 1 below.

As shown in Figure 7, in the XRD pattern of Example 1, the crystal surface (111) of the 41.181FePt phase with the strongest signal; in addition, Figure 8 shows the standard of Pt ₃ Fe and the standard of Fe _1.28 Pt _0.72 from bottom to top. XRD patterns of FePt standard products, Fe ₄ C, and Comparative Example 1. It is obvious from the comparison of Fig. 7 and Fig. 8 that the crystal plane (111) representing the FePt phase in Fig. 7 has a strong signal and its characteristic peak is very narrow, and there are few impurity phases; on the contrary, Fig. 8 represents the FePt phase The signal on the crystal plane (111) of the crystalline surface is relatively weak and its characteristic peak is relatively wide, which means that the Fe-Pt-based target of Comparative Example 1 has multiple alloy phases.

Minute Analyze 3 : The amount of carbon precipitated on the surface of the iron-platinum-based target

A 30 mm×30 mm×3 mm test piece was obtained from the iron-platinum-based targets of Examples 1 to 14 and Comparative Examples 1 to 9 by wire cutting. The test pieces of the iron-platinum-based targets of the foregoing Examples 1 to 14 and Comparative Examples 1 to 9 were respectively ground with sandpaper numbers #80, #240, #400, #800, #1500, #2500 and #4000 ; When grinding, it is necessary to rotate 90 cross grinding to remove grinding marks, until grinding to #4000 sandpaper; after the grinding is completed, put it in an alcohol solution and clean it with an ultrasonic cleaner for 5 minutes.

Then, put each cleaned test piece into 100 ml of ultrapure water, oscillate at 25°C for 10 minutes using an ultrasonic cleaner, and then detect the oscillating effect with an inductively coupled plasma emission spectrometer (ICP-OES) The carbon content of the pure aqueous solution represents the amount of carbon precipitated on the surface of the iron-platinum-based target, and the results are described in Table 1 below.

Table 1: The composition, sintering method, sintering temperature of the iron-platinum-based targets of Examples 1-14 and Comparative Examples 1-9, as well as the carbon phase characteristics, XRD characteristics, and the amount of precipitated carbon contained therein. Target number Fe (at%) Pt (at%) C (at%) BN (at%) Ag (at%) Cu (at%) Sintering method Sintering temperature (°C) Average size of carbon phase (μm) Carbon phase average axial length ratio (111) FWHM of crystal plane (°) Carbon precipitation (ppm) Example 1 45 30 25 0 0 0 HIP 800 0.378 1.87 0.187 41 Example 2 35 30 35 0 0 0 HIP 900 1.789 2.78 0.257 98 Example 3 25 30 45 0 0 0 SPS 700 0.614 1.95 0.214 68 HIP 1000 Example 4 40 15 45 0 0 0 HIP 1000 1.487 2.66 0.159 105 Example 5 50 35 15 0 0 0 HIP 1100 1.754 2.91 0.288 96 Example 6 55 20 25 0 0 0 HIP 800 0.339 1.77 0.201 45 Example 7 45 30 25 0 0 0 HIP 1000 0.597 1.91 0.167 59 Example 8 45 30 25 0 0 0 SPS 1000 1.154 2.87 0.258 95 HIP 1000 Example 9 45 30 20 5 0 0 HIP 900 0.348 1.9 0.223 29 Example 10 40 30 twenty two 8 0 0 HIP 900 0.321 1.78 0.185 25 Example 11 44 30 25 0 1 0 HIP 900 0.366 1.67 0.174 65 Example 12 44 30 25 0 0 1 HIP 900 0.374 1.76 0.167 54 Example 13 43.5 30 25 0 1.5 0 HIP 900 0.364 1.34 0.147 58 Example 14 43.5 30 25 0 0 1.5 HIP 900 0.389 1.65 0.16 53 Comparative example 1 35 30 35 0 0 0 HP 1100 5.325 3.67 0.777 194 Comparative example 2 45 30 25 0 0 0 SPS 800 2.912 3.55 0.676 154 HIP 1100 Comparative example 3 45 30 25 0 0 0 HP 1100 9.987 7.35 0.762 445 Comparative example 4 45 30 25 0 0 0 SPS 800 4.345 5.12 0.78 286 HIP 900 Comparative example 5 45 30 25 0 0 0 SPS 800 2.477 3.49 0.76 159 HIP 900 Comparative example 6 35 30 35 0 0 0 SPS 800 7.798 6.99 0.841 422 HIP 900 Comparative example 7 35 30 35 0 0 0 SPS 800 8.889 5.97 0.625 322 HIP 900 Comparative example 8 25 15 60 0 0 0 HIP 1000 11.213 9.21 0.857 798 Comparative example 9 70 20 10 0 0 0 HIP 1100 3.23 2.22 0.341 144

Discussion of experimental results

Combining the results of Examples 1 to 14 and Comparative Examples 1 to 9 in analysis 1-2, 1-3, and analysis 3, we can see that by controlling the amount of carbon raw material and its appropriate pretreatment, the simultaneous treatment of carbon, iron, and platinum raw materials After mechanical alloying treatment and the use of HIP to sinter the iron-platinum-based alloy powder, the carbon content in the iron-platinum-based target material does not exceed 45 at%, and the average size of the carbon phase in the metallographic phase of the iron-platinum-based target material is less than Or equal to 2 μm, and the average axial length ratio of the carbon phase is less than 3. Accordingly, the amount of carbon precipitated on the surface of the iron-platinum-based targets of Examples 1 to 14 is indeed lower than the amount of carbon precipitated on the surface of the iron-platinum-based targets of Comparative Examples 1 to 9.

In addition, from the results of analyzing the amount of precipitated carbon of the iron-platinum-based targets of Examples 1 to 14 in 2, it can be seen that in the X-ray diffraction pattern of the iron-platinum-based targets, the (111) crystal plane characteristics of the iron-platinum alloy The half-height widths of the peaks are all less than 0.3°. In the X-ray diffraction patterns of the Fe-Pt-based targets of Comparative Examples 1 to 9, the FWHM of the (111) crystal plane characteristic peak of the Fe-Pt alloy is all greater than 0.3°.

Furthermore, by analyzing the precipitated carbon of the iron-platinum-based targets of Examples 1, 6 to 8 (C accounted for 25 at%) in Example 5 (C accounted for 15 at%) The comparison result shows that when diamond carbon powder is selected as the carbon raw material, even if the iron-platinum-based target materials of Examples 1, 6 to 8 contain more carbon components, it is still comparable to Example 5 where graphite carbon powder is selected as the carbon raw material. The iron-platinum-based target material precipitates less carbon. It can be seen that selecting diamond carbon powder as the carbon raw material to prepare iron-platinum-based targets can help reduce the amount of carbon precipitated on the surface of iron-platinum-based targets.

Furthermore, the comparison of the amount of precipitated carbon in the iron-platinum-based targets of Examples 1 to 8 and Examples 9 and 10 in 2 shows that when the iron-platinum-based target contains boron nitride, it can be further suppressed The amount of carbon deposited on the surface of the iron-platinum-based targets of Examples 9 and 10.

From the results of analyzing the amount of precipitated carbon in Comparative Examples 1 to 9 in 3, comparing Comparative Example 4 and Comparative Example 6, and comparing Comparative Example 5 and Comparative Example 7, it can be seen that if the carbon raw material is first subjected to high-energy The step of mechanical polishing can reduce the amount of carbon deposited on the surface of the iron-platinum-based target. However, even if the carbon raw material has been processed in the high-energy mechanical grinding step, if the content of the carbon raw material is not simultaneously controlled within an appropriate range (for example, Comparative Example 8), or a sintering method that does not include the hot pressure equalization sintering method (for example, Comparative example 1), or the carbon raw material, the iron raw material and the platinum raw material are not mechanically alloyed at the same time (for example, Comparative Examples 4 and 5), the amount of carbon precipitated on the surface of the iron-platinum-based target material cannot be reduced to a suitable situation.

It can be seen that by appropriately controlling the carbon content of the iron-platinum-based target and controlling the carbon phase of its metallography, this creation can not only improve the uniformity of the phase composition of the iron-platinum-based target, but also effectively suppress Black carbon precipitates on the surface of the iron-platinum-based target material, thereby reducing the probability of abnormal discharge of the iron-platinum-based target material during the sputtering process, reducing the problem of particles falling on the film layer, and improving the magnetism formed by the sputtering Film quality and yield of the recording layer.

The above-mentioned embodiments are only examples to illustrate the creation, and do not limit the scope of rights claimed by the creation in any respect. The scope of rights claimed in this creation should be subject to the scope of the patent application, not limited to the specific embodiments described above.

no.

Figure 1 is a metallographic diagram of the iron-platinum-based target material of Example 1 magnified 500 times by SEM; 2 is a metallographic diagram of the iron-platinum-based target material of Example 6 magnified 500 times by SEM; Fig. 3 is a metallographic diagram of the iron-platinum-based target material of Comparative Example 1 magnified 1000 times by SEM; Fig. 4 is a metallographic image of the iron-platinum-based target material of Comparative Example 2 magnified 500 times by SEM; Fig. 5 is a metallographic diagram of the iron-platinum-based target of Comparative Example 4 magnified 500 times by SEM; Fig. 6 is a metallographic image of the iron-platinum-based target material of Comparative Example 5 magnified 500 times by SEM; Fig. 7 is the XRD pattern of the iron-platinum-based target of Example 1; FIG. 8 is the XRD pattern of the iron-platinum-based target of Comparative Example 1. FIG.

no.

Claims (14)

An iron-platinum-based target material comprising iron, platinum, and carbon; wherein, based on the total number of atoms of the overall iron-platinum-based target material, the carbon content is greater than or equal to 15 atomic percent and less than or equal to 45 atomic percent; In the metallographic phase of the iron-platinum-based target material, the average size of the carbon phase is less than or equal to 2 microns, and the average axial length ratio of the carbon phase is less than 3. The iron-platinum-based target material according to claim 1, wherein, based on the total number of atoms of the whole iron-platinum-based target material, the iron content is greater than or equal to 20 atomic percent and less than or equal to 70 atomic percent; the platinum content is It is greater than or equal to 10 atomic percent and less than or equal to 40 atomic percent. The iron-platinum-based target material according to claim 1, wherein the carbon is diamond carbon, graphite carbon, carbon nanotube, or a combination thereof. The iron-platinum-based target material according to claim 3, wherein the carbon is diamond carbon. The iron-platinum-based target material according to claim 1, wherein, in the X-ray diffraction pattern of the iron-platinum-based target material, the full width at half maximum of the (111) crystal plane characteristic peak of the iron-platinum alloy is less than 0.3°. The iron-platinum-based target material according to any one of claims 1 to 5, wherein the iron-platinum-based target material further comprises boron nitride. The iron-platinum-based target material according to any one of claims 1 to 5, which further comprises copper, silver, or a combination thereof. A method for manufacturing an iron-platinum-based target material, the steps include: Step (A): Grind the carbon raw material by a high-energy mechanical grinding method to obtain a ground carbon powder with an average particle size of 0.3 to 3 microns; Step (B): mixing the ground carbon powder, iron raw material, and platinum raw material and performing mechanical alloying to obtain an iron-platinum-based alloy powder; and Step (C): Sinter the iron-platinum-based alloy powder by a sintering method including a hot-equalizing pressure sintering method to obtain an iron-platinum-based target; wherein, based on the total number of atoms of the whole iron-platinum-based target, the carbon content is It is greater than or equal to 15 atomic percent and less than or equal to 45 atomic percent; in the metallographic phase of the iron-platinum-based target, the average size of the carbon phase is less than or equal to 2 microns, and the average axial length ratio of the carbon phase is less than 3. The method for manufacturing an iron-platinum-based target material according to claim 8, wherein, in the iron-platinum-based target material, the content of iron in the whole iron-platinum-based target material is greater than or equal to 20 atomic percent and less than or equal to 70 atomic percent ; The content of platinum in the whole iron-platinum-based target is greater than or equal to 10 atomic percent and less than or equal to 40 atomic percent. The method for manufacturing an iron-platinum-based target material according to claim 8, wherein, in the step (B), the average particle size of the iron raw material is 20 to 80 microns, and the average particle size of the platinum raw material is 1 micron To 10 microns. The method for manufacturing an iron-platinum-based target material according to any one of claims 8 to 10, wherein step (B) includes: Step (B1): mixing the ground carbon powder, iron raw material, and platinum raw material to obtain a mixture; and Step (B2): the mixture is mechanically alloyed to obtain the iron-platinum-based alloy powder. The method for manufacturing an iron-platinum-based target material according to any one of claims 8 to 10, wherein the step (B) further includes boron nitride with an average particle size of less than 3.0 microns, and an average particle size of 50 microns to 150 microns of copper raw materials, silver raw materials with an average particle size of 5 to 10 microns, or a combination thereof. The method for manufacturing an iron-platinum-based target material according to any one of claims 8 to 10, wherein the sintering method in step (C) further includes a spark plasma sintering method. The method for manufacturing an iron-platinum-based target material according to claim 13, wherein, in the step (C), the sintering temperature is 500°C to 1300°C, and the sintering pressure is 50 to 200 megapascals.

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