CN117980526A

CN117980526A - Sputtering target containing hard nitride

Info

Publication number: CN117980526A
Application number: CN202280059213.4A
Authority: CN
Inventors: 山本孝充; 西浦正纮; 渡边恭伸
Original assignee: Tanaka Kikinzoku Kogyo KK
Current assignee: Tanaka Kikinzoku Kogyo KK
Priority date: 2021-09-08
Filing date: 2022-08-08
Publication date: 2024-05-03
Also published as: WO2023037810A1; TW202317793A; JP2023039187A; TWI825922B

Abstract

The present invention provides a hard nitride-containing sputtering target which can prevent arc light from being generated during sputtering due to the mixing of relatively coarse zirconia particles and can inhibit particle generation during film formation, and a method for producing the same. A sputtering target containing a hard nitride, characterized in that the sputtering target comprises an alloy phase containing Fe or Co and a nonmagnetic phase containing a hard nitride selected from AlN, BN, cr ₂N、Si₃N₄, hfN, nbN, taN, tiN, VN and any combination thereof, and the concentration of Zr impurity when measured as metallic Zr is limited to 1000ppm or less, and the Vickers hardness Hv measured under a load condition of 3kgf is 200 to 600.

Description

Sputtering target containing hard nitride

Technical Field

The present invention relates to a hard nitride-containing sputtering target and a method for producing the same, and more particularly to a hard nitride-containing sputtering target composed of an alloy phase containing Fe or Co and a non-magnetic phase containing a hard nitride selected from AlN, BN, cr ₂N、Si₃N₄, hfN, nbN, taN, tiN, VN, and any combination thereof, and a method for producing the same.

Background

As a sputtering target for producing a granular-structure magnetic thin film for a magnetic recording medium such as a hard disk drive, a sintered body containing an alloy phase containing Fe or Co as a main component, and a non-magnetic material such as an oxide, carbon, or boron nitride is used.

It was confirmed that the generation of particles during film formation can be reduced by forming a non-magnetic material particle-dispersed structure in which an oxide is uniformly and finely dispersed between alloy phases in a sputtering target containing the oxide as a non-magnetic material. In order to uniformly and finely disperse the oxide between the alloy phases, the oxide and the raw material powder forming the alloy phases are mixed by strong stirring using a medium stirring mill such as a zirconia ball mill (japanese patent No. 4673448 and japanese patent No. 6728094). A sputtering target containing a nitride instead of an oxide has been proposed, but a method of mixing by intense stirring using a zirconia ball mill is adopted similarly to the oxide (japanese patent No. 5913620 and japanese patent No. 6526837).

Japanese patent No. 4673448 discloses a nonmagnetic particle dispersion type ferromagnetic sputtering target having the following composition: a phase (A) having non-magnetic particles in which oxides are uniformly finely dispersed, and a spherical alloy phase (B) having a diameter of 50 to 200 [ mu ] m in the phase (A), wherein 25mol% or more of Cr is concentrated near the center of the spherical alloy phase (B), and the content of Cr is lower in the outer peripheral portion than in the center portion. The sputtering target was produced as follows: the sputtering target is produced by sealing a metal powder having a maximum particle diameter of 20 μm or less and a non-magnetic material powder having a maximum particle diameter of 5 μm or less together with zirconia balls in a ball mill pot having a capacity of 10 liters, mixing the powder by rotating for 20 hours while pulverizing, mixing the powder with a Co-Cr spherical powder having a diameter of 50 to 200 μm in a planetary motion mixer, and sintering the mixture.

Japanese patent No. 6728094 discloses the following inventions: in order to suppress the generation of particles during sputtering, a Co-Pt phase, a Co phase and a non-magnetic material are contained, and the Co-Pt alloy phase is made finer and the Co phase is made coarser. Specifically, it is described that a Co-Pt alloy powder having an average particle diameter of 0.1 μm or more and 7 μm or less, a Co phase having an average particle diameter of 30 μm or more and 300 μm or less, a nonmagnetic material having an oxide having an average particle diameter of 0.05 μm or more and 2 μm or less, a Co-Pt alloy powder having a median diameter of 0.1 μm or more and 7 μm or less, and a nonmagnetic material having a median diameter of 0.05 μm or more and 2 μm or less are used as a raw material. As a method for mixing the raw material powder, a method is described in which the raw material powder is enclosed together with zirconia balls in a ball mill having a capacity of 10 liters, and the ball mill is rotated for 20 hours to mix the raw material powder.

Japanese patent No. 5913620 discloses that: in an Fe-Pt sintered body sputtering target using hexagonal BN as a nonmagnetic material, the orientation of the hexagonal BN is improved to suppress abnormal discharge during sputtering and reduce the amount of particles generated. Specifically, it is described that Fe-Pt alloy powder was put into a medium stirring mill having a capacity of 5L together with zirconia balls, treated at a rotation speed of 300rpm for 2 hours to prepare Fe-Pt alloy powder having an average particle diameter of 10. Mu.m, and then the Fe-Pt alloy powder and hexagonal BN powder were mixed in a V-type mixer, and further mixed by using a 150 μm sieve. However, hexagonal BN has a low hardness, and the sputtering target has an insufficient hardness, and there is a problem that cracks occur during sputtering.

Japanese patent No. 6526837 discloses a Fe-Pt-based sputtering target and Co-Pt-based sputtering target using cubic BN which is less likely to cause cracks in BN particles than hexagonal BN, and describes that raw material powder is put into a medium stirring mill having a capacity of 5L together with zirconia balls, and mixed by rotating (rotation speed 300 rpm) for 2 hours, and pulverized so that the median diameter (D50) of the raw material mixed powder is 0.3 μm or more and 20 μm or less, preferably 5 μm or less.

However, according to the experiments of the present inventors, it was found that when a nitride is used as a nonmagnetic material, the nitride is hard during mixing of the raw material powder, and therefore, the inner wall of the zirconia balls and the medium stirring mill is worn, relatively coarse zirconia particles are mixed, and the specific resistance of the coarse zirconia particles is higher than that of the nitride and carbide, and therefore, arc light is easily generated during sputtering, and particle generation during film formation is easily generated.

Prior art literature

Patent literature

Patent document 1: japanese patent No. 4673448

Patent document 2: japanese patent 6728094

Patent document 3: japanese patent 5913620

Patent document 4: japanese patent No. 6526837

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a hard nitride-containing sputtering target which can solve the above-described conventional problems, prevent the generation of arc light during sputtering due to the mixing of relatively coarse zirconia particles, and suppress the generation of particles during film formation, and a method for producing the same.

Means for solving the problems

The present inventors have found that arc light in sputtering of a sputtering target containing a hard nitride is caused by the mixed presence of relatively coarse zirconia particles, and have thought that by preventing the mixing of zirconia impurity particles from a zirconia ball mill which is generally used in mixing raw material powders in the production process of a sputtering target, arc light in sputtering can be suppressed, leading to completion of the present invention.

According to the present invention, there is provided a sputtering target containing a hard nitride, which is composed of an alloy phase containing Fe or Co and a non-magnetic phase containing a hard nitride selected from AlN, BN, cr ₂N、Si₃N₄, hfN, nbN, taN, tiN, VN and any combination thereof,

The Zr impurity concentration when measured as metallic Zr is limited to 1000ppm or less, and the Vickers hardness Hv measured under a load of 3kgf is 200 to 600.

The Zr impurity concentration is preferably limited to 500ppm or less.

The above-mentioned non-magnetic phase preferably satisfies at least one of the following:

the average particle diameter obtained by image analysis of 180 [ mu ] m x 180 [ mu ] m of an observation field of view of EPMA surface analysis at a magnification of 500 is 4 [ mu ] m or more and 20 [ mu ] m or less;

the average particle diameter obtained by image analysis of 90 [ mu ] m X90 [ mu ] m in the observation field of EPMA surface analysis at a magnification of 1000 is 2 [ mu ] m or more and 20 [ mu ] m or less; and

The average particle diameter obtained by image analysis of the observation field of 30 [ mu ] m X30 [ mu ] m in EPMA surface analysis at a magnification of 3000 is 1 [ mu ] m or more and 20 [ mu ] m or less.

The content of the nonmagnetic phase in the sputtering target is preferably 5mol% or more and 50mol% or less.

The nonmagnetic phase may further contain one or more kinds selected from C, B ₂O₃ and SiO ₂.

The alloy phase may contain Pt in an amount of 0mol% or more and 60mol% or less.

The alloy phase may further contain one or more elements selected from Ag, au, cr, cu, ge, ir, ni, pd, rh, ru and B.

According to the present invention, there is also provided a method for producing the above-mentioned sputtering target containing a hard nitride. The manufacturing method of the present invention is characterized by comprising: the raw material powders constituting the alloy phase and the nonmagnetic phase are mixed at a rotational speed of 50rpm to 150rpm by using a zirconia ball mill for 2 to 6 hours to prepare a mixed powder, and the mixed powder is sintered.

The raw material powder constituting the alloy phase is preferably a metal powder of each raw material or an atomized alloy powder of Fe system or Co system.

The raw material powder constituting the nonmagnetic phase preferably contains a hard nitride powder having an average particle diameter D50 of 1 μm or more and 40 μm or less.

Effects of the invention

The hard nitride-containing sputtering target of the present invention prevents the incorporation of relatively coarse zirconia impurity particles having a high resistivity, and the Zr impurity concentration when measured as metallic Zr is limited to 1000ppm or less, so that the occurrence of arc light during sputtering can be suppressed, and the particles derived from zirconia particles at the time of film formation can be reduced.

Drawings

FIG. 1 is a graph showing the relationship between Zr concentration and the number of grains in the sputtering targets of examples and comparative examples.

FIG. 2 is a graph showing the relationship between the Vickers hardness and the particle count of the sputtering targets of examples and comparative examples.

Fig. 3 is an SEM observation photograph (magnification 1000) of the structure of the sputtering target of example 1.

Fig. 4 is an SEM observation photograph (magnification 1000) of the structure of the sputtering target of example 2.

Fig. 5 is an SEM observation photograph (magnification 1000) of the structure of the sputtering target of comparative example 2.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The hard nitride-containing sputtering target of the present invention is characterized in that it comprises an alloy phase containing Fe or Co and a nonmagnetic phase containing a hard nitride selected from AlN, BN, cr ₂N、Si₃N₄, hfN, nbN, taN, tiN, VN and any combination thereof, and the Zr impurity concentration when measured as metallic Zr is limited to 1000ppm or less, preferably 500ppm or less, more preferably 300ppm or less, and the Vickers hardness Hv measured under a load condition of 3kgf is 200 or more and 600 or less, preferably 250 or more and 600 or less.

The present invention relates to a sputtering target containing a hard nitride, which contains a hard nitride as a nonmagnetic material particle. As the hard nitride, alN, BN, cr ₂N、Si₃N₄, hfN, nbN, taN, tiN, VN, and any combination thereof are contained. Regarding the hardness (GPa) of each nitride, alN was 12.0, cr ₂ N was 15.4, si ₃N₄ was 19.4, hfN was 15.7, nbN was 14.3, taN was 23.7, tiN was 20.1, VN was 12.8, cubic BN was 46.1, hexagonal BN was 2.0 (data handbook high melting point compound review, ceramic handbook: from basic to application examples, CERAMIC HARDNESS (ceramic hardness)).

As BN used for a sputtering target, cubic BN and hexagonal BN are known, and cubic BN called hardness inferior to diamond is used in the present invention. If cubic BN is contained, hexagonal BN may be mixed.

The nonmagnetic phase contains a hard nitride having an average particle diameter of 1 μm or more, preferably 2 μm or more and 20 μm or less. The average particle size of the nonmagnetic phase can be measured by image analysis of the EPMA plane analysis result. Image analysis based on EPMA plane analysis is performed by the following steps.

First, a sputtering surface of a sputtering target was polished, and an element mapping image was obtained at a magnification of 100 using an EPMA apparatus. The obtained element map image is binarized by a "surface processing" function attached to the EPMA device. The element map image after the binarization was analyzed by image analysis software (ImageJ 1.53 e) to determine the average particle size of the nitride. In the case where the element constituting the nitride is one type (for example, element a) other than N (nitrogen), the positions of both element N and element a are detected from the element map image calculation. When the number of elements constituting the nitride is two or more, the element map images of all elements except the element N are synthesized from the map images of the elements, and the positions where both the element other than the element N and the element N are detected are calculated, and the Average Size (Average Size) is obtained, and the Average particle diameter (μm) is calculated by the following equation.

When the obtained average particle diameter is equal to or smaller than the criterion of each magnification shown in table 1, the magnifications are increased stepwise in the order of the magnifications S00, 1000, 3000, 10000 until the average particle diameter becomes larger than the criterion, and the average particle diameter at each magnification is calculated by repeating a series of operations.

TABLE 1

Table 1 criterion

100 Times of	18μm
		500 Times	3.6μm
1000 Times	1.8μm
		3000 Times	0.6μm
10000 Times	Without any means for

Since the fine nonmagnetic phase cannot be observed at the observation magnification in EPMA plane analysis, the error in the average particle diameter increases, and therefore the range of the average particle diameter based on the observation magnification is classified as follows. The hard nitride-containing sputtering target of the present invention preferably satisfies at least one of the following (a) to (C).

(A) The average particle diameter obtained by image analysis of 180 μm×180 μm in the observation field of EPMA surface analysis at a magnification of 500 is 3.6 μm or more and 20 μm or less, preferably 4 μm or more and 15 μm or less;

(B) The average particle diameter obtained by image analysis of 90 μm×90 μm in the observation field of EPMA surface analysis at a magnification of 1000 is 1.8 μm or more and 20 μm or less, preferably 1.8 μm or more and 4 μm or less, more preferably 1.8 μm or more and 3.6 μm or less;

(C) The average particle diameter obtained by image analysis of 30 μm×30 μm in the observation field of EPMA surface analysis at a magnification of 3000 is 1 μm or more and 20 μm or less, preferably 1 μm or more and 2 μm or less, more preferably 1 μm or more and 1.8 μm or less.

The content of the nonmagnetic phase in the sputtering target varies depending on the physical properties required for the deposition layer to be formed using the sputtering target, and is usually preferably 5mol% or more and 50mol% or less, more preferably 5mol% or more and 45mol% or less. If the content of the nonmagnetic phase is within the above range, the magnetic properties of the deposited layer can be well maintained, and the magnetic phase is finely dispersed between the magnetic materials in the deposited layer, thereby functioning as a grain boundary material that separates adjacent magnetic materials from each other.

The nonmagnetic phase may further contain one or more nonmagnetic materials selected from C, B ₂O₃ and SiO ₂, which are generally used in sputtering targets. The content of the optionally added nonmagnetic material in the sputtering target is preferably 0mol% or more and 25mol% or less, more preferably 0mol% or more and 20mol% or less. If the content of the optional nonmagnetic material is within the above range, the magnetic properties of the deposited layer can be well maintained, and the nonmagnetic material is finely dispersed between the magnetic materials in the deposited layer, thereby functioning as a grain boundary material for isolating adjacent magnetic materials from each other.

The alloy phase contains Fe or Co as a ferromagnetic material. The alloy may be contained as Fe alone or Co alone or as an alloy of Fe and Co or as an alloy of Fe and other elements, as an alloy of Co and other elements or as an alloy of Fe and Co and other elements. Fe or Co is contained as a main component of the sputtering target. The content of Fe in the alloy phase containing Fe without Co is preferably 35mol% or more and 100mol% or less, more preferably 40mol% or more and 100mol% or less. The content of Co in the alloy phase containing Co without Fe is preferably 50mol% or more and 100mol% or less, more preferably 55mol% or more and 100mol% or less. The total content of Fe and Co in the alloy phase when Fe or Co is contained is preferably 35mol% or more and 100mol% or less, more preferably 40mol% or more and 100mol% or less. The total amount of Fe and Co in the alloy phase when Fe and Co are contained is preferably 50mol% or more and 100mol% or less, more preferably 60mol% or more and 100mol% or less, the content of Fe in the alloy phase is preferably 30mol% or more and 70mol% or less, more preferably 35mol% or more and 65mol% or less, and the content of Co in the alloy phase is preferably 20mol% or more and 50mol% or less, more preferably 25mol% or more and 45mol% or less.

The alloy phase preferably contains Pt in an amount of 0mol% or more and 60mol% or less, and more preferably more than 0mol% and 55mol% or less.

The alloy phase may further contain one or more elements selected from Ag, au, cr, cu, ge, ir, ni, pd, rh, ru and B. The content of the optionally added element in the alloy phase is preferably 0mol% or more and 30mol% or less, more preferably 0mol% or more and 25mol% or less. If the content of the element optionally added in the alloy phase is within the above range, the magnetic properties of the deposited layer can be well maintained.

As the sputtering target of the present invention, fe alloy-nitride, fe alloy-C-nitride, fe alloy-oxide-nitride, fe alloy-C-oxide-nitride, co alloy-C-nitride, co alloy-oxide-nitride, co alloy-C-oxide-nitride, fePt alloy-C-nitride, fePt alloy-oxide-nitride, fePt alloy-C-oxide-nitride, coPt alloy-C-nitride, coPt alloy-oxide-nitride, coPt alloy-C-oxide-nitride, feCo alloy-C-nitride, feCo alloy-oxide-nitride, feCo alloy-C-oxide-nitride, feCoPt alloy-C-nitride, fePt alloy-C-oxide-nitride, feCoPt alloy-C-nitride may be mentioned. As specific design compositions, there may be preferably mentioned Fe-51Pt-7Si₃N₄、Fe-40Pt-20AlN、Fe-39Pt-25TaN、Fe-38Pt-15Cr₂N、Fe-35Pt-25VN、Fe-40Pt-20NbN、Fe-40Pt-20HfN、Fe-28Pt-30BN、Fe-35Pt-25TiN、Fe-41Pt-5Cu-5BN-8Si₃N₄、Fe-46Pt-3B₂O₃-8Si₃N₄、Fe-41Pt-4SiO₂-10AlN-3Si₃N₄、Fe-21Pt-21Co-10C-20AlN、Fe-30Pt-5C-30AlN、Fe-30Pt-5Ag-6C-11BN-20AlN、Fe-32Pt-6B-6Rh-20HfN、Fe-34Pt-3Ge-5C-20TiN、Co-23Pt-7Si₃N₄、Co-20Pt-19AlN、Co-19Pt-25TaN、Co-14Pt-30BN、Co-16Pt-4Cr-4SiO₂-15Cr₂N、Co-13Pt-6Ru-8Cr-16C-22VN、Co-15TiN、Fe-20TaN、Co-48Fe-20AlN.

The design composition of the sputtering target of the present invention may be repeated as that of the known sputtering target, but the Zr concentration when measured as metallic Zr is limited to 1000ppm or less, preferably 500ppm or less, more preferably 300ppm or less, unlike the known sputtering target. The Zr impurity of the sputtering target of the present invention is different from the inevitable impurities in the composition of the known sputtering target, and is controlled so as to be a content equal to or less than a limit value in the manufacturing process. As shown in examples and comparative examples described later, it was confirmed that: even in the sputtering target of the same design composition, if the Zr concentration is limited to 1000ppm or less, the generation of particles is remarkably suppressed.

The sputtering target of the present invention is characterized in that the vickers hardness Hv measured under a load of 3kgf is 200 or more and 600 or less, preferably 250 or more and 600 or less. It is considered that the higher the Vickers hardness, the more particles are generated, but if the Zr concentration is limited to 1000ppm or less, as shown in examples and comparative examples described later, it is confirmed that: even in the case of the sputtering targets having the same design composition, the occurrence of particles is remarkably suppressed when the vickers hardness Hv is 200 or more and 600 or less.

The hard nitride-containing sputtering target of the present invention can be produced by a method characterized by comprising: the raw material powders constituting the alloy phase and the nonmagnetic phase are mixed at a rotational speed of 50rpm to 150rpm by using a zirconia ball mill for 2 to 6 hours to prepare a mixed powder, and the mixed powder is sintered.

In the production method of the present invention, the stirring and mixing conditions of the raw material powder are set as follows: the process is carried out at a rotation speed of 50rpm to 150rpm, preferably 50rpm to 100rpm, more preferably 50rpm to 75rpm, using a zirconia ball mill for 2 hours to 6 hours, preferably 3 hours to 5 hours. In general, a zirconia ball mill is used for stirring and mixing, in which zirconia balls are caused to collide with raw material powder at a high speed by rotating the mill at a high speed, and the raw material powder is ground between the zirconia balls for a long period of time, whereby the raw material powder is crushed by applying strong mechanical energy thereto, and the fine raw material powder is kneaded to form a homogeneous powder mixture. The present inventors have found that when the raw material powder contains hard particles, zirconia balls are abraded and a small amount of zirconia is mixed as an impurity, and have found optimal mixing conditions for suppressing abrasion of zirconia balls while achieving homogeneous mixing of the raw material powder. In the present invention, it has been found that by suppressing the rotation speed to a low speed and making the collision relatively gentle and making the stirring time relatively short, abrasion of zirconia balls can be prevented even in the raw material powder containing hard nitride particles, and mixing of zirconia into the mixture of the raw material powder can be suppressed.

The raw material powder constituting the alloy phase may be a metal powder or an atomized alloy powder of Fe system or Co system.

As the Fe powder, a powder having an average particle diameter D50 of 1 μm or more and 10 μm or less, preferably 2 μm or more and 8 μm or less can be used. If the average particle diameter is too small, there is a possibility that there is a risk of ignition and the concentration of unavoidable impurities becomes high, and if the average particle diameter is too large, there is a possibility that the non-magnetic material particles cannot be uniformly dispersed.

As the Co powder, a powder having an average particle diameter D50 of 1 μm or more and 10 μm or less, preferably 2 μm or more and 8 μm or less can be used. If the average particle diameter is too small, there is a possibility that there is a risk of ignition and the concentration of unavoidable impurities becomes high, and if the average particle diameter is too large, there is a possibility that the non-magnetic material particles cannot be uniformly dispersed.

As the Pt powder, a powder having an average particle diameter D50 of 0.1 μm or more and 10 μm or less, preferably 0.3 μm or more and 6 μm or less can be used. If the average particle diameter is too small, the concentration of unavoidable impurities may become high, and if the average particle diameter is too large, the particles of the nonmagnetic material may not be uniformly dispersed.

As the optionally added elemental powder, a powder having an average particle diameter D50 of 0.1 μm or more and 30 μm or less, preferably 0.5 μm or more and 20 μm or less can be used. If the average particle diameter is too small, the concentration of the unavoidable impurities may become high, and if the average particle diameter is too large, the dispersion may not be uniform.

As the Fe-based or Co-based atomized alloy powder, an atomized alloy powder having an average particle diameter D50 of 1 μm or more and 10 μm or less, preferably 2 μm or more and 8 μm or less can be used. If the average particle diameter is too small, the concentration of unavoidable impurities may become high, and if the average particle diameter is too large, the particles of the nonmagnetic material may not be uniformly dispersed.

The raw material powder constituting the nonmagnetic phase contains a hard nitride powder having an average particle diameter D50 of 1 μm or more and 40 μm or less, preferably 2 μm or more and 35 μm or less. As the hard nitride powder, alN, BN, cr ₂N、Si₃N₄, hfN, nbN, taN, tiN, VN, and any combination thereof are used. As BN, cubic BN was used. If the average particle diameter of the hard nitride powder is within the above range, a good dispersion state can be achieved.

The raw material powder constituting the nonmagnetic phase may further contain one or more nonmagnetic materials selected from C, B ₂O₃ and SiO ₂ having an average particle diameter D50 of 1 μm or more and 10 μm or less, preferably 1 μm or more and 8 μm or less. If the average particle diameter of the additional non-magnetic material powder is within the above range, a good dispersion state can be achieved.

The sintering conditions of the mixed powder are preferably set to a sintering temperature of 800 ℃ to 1300 ℃, preferably 900 ℃ to 1250 ℃, and a sintering pressure of 30MPa to 120MPa, preferably 50MPa to 100 MPa.

Examples

Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited thereto. The Zr concentration, vickers hardness, average particle diameter of the hard nitride nonmagnetic phase, relative density, and particle number of the sputtering targets in the following examples and comparative examples were measured as follows.

[ Zr concentration ]

Test pieces having a diameter of 30mm were cut from the sputtering target, the horizontal plane of the sputtering target with respect to the sputtering surface was polished with SiC polishing papers #80, #320 and #1200, and the Zr concentration was measured by inputting the conditions of table 2 into an EZ scanner using a fluorescence X-ray analyzer (ZSX PrimusIV, rigaku, inc.) equipped with an X-ray tube of Rh.

TABLE 2

TABLE 2 automatic setting conditions

Sample type	Metal & alloy
		Measurement range	B～U
Diameter measurement	20mm
		Measuring time	Standard of

[ Vickers hardness ]

The measurement was carried out in accordance with JIS Z2244. Specifically, the horizontal plane of the sputtering target with respect to the sputtering surface was polished with the SiC polishing papers #80, #320 and #1200, then polished with diamond abrasive grains having a particle diameter of 1 μm, the size of the indentation was observed with a microscope when a test load of 3.00kgf was applied to the diamond indenter of a regular square pyramid having a face angle of 136 ° with a vickers hardness tester (HV-115, sanfeng, ltd.), the length of the straight line connecting the diagonal lines was measured, the surface area (mm ²) of the indentation was calculated, and the test load (kgf)/surface area (mm ²) of the indentation was calculated.

[ Average particle diameter of hard nitride nonmagnetic phase ]

After polishing the vertical surfaces of the sputtering targets with respect to the sputtering surfaces with the SiC polishing papers #80, #320 and #1200, the sputtering targets were polished with diamond sprays having a particle diameter of 1 μm, and element mapping images were obtained using EPMA apparatuses (JXA-8500F, japan electronics corporation) under EPMA analysis conditions shown in tables 3 and 4.

TABLE 4

TABLE 4 EPMA analysis Condition 2

The obtained element map image was subjected to binarization processing using a "face processing" function attached to an EPMA device (JXA-8500F). Specifically, an image in which the element map image is displayed with the maximum map number 9 and binarized is selected, and the upper limit and the lower limit are checked on the "level change" screen. The "subtraction of constant" is selected in the "map calculation" screen, and the value of the lower limit checked in the "gradation change" screen is inputted to K. Further, the "division with constant" is selected on the "map calculation" screen, and a value obtained by subtracting the value of the lower limit from the value of the upper limit checked on the "gradation change" screen is input to K. The "display mode" selection screen is changed to the contents of table 5. The "level change" screen is changed to the contents of table 6.

TABLE 5

Table 5 shows modes

Intensity/concentration	Intensity mapping
		Display color	Gray scale
Color bar	On a map
		Color number	2
Step spacing	Equally spaced apart
		Mapping display	Interpolation-free

TABLE 6

Table 6 level change

Grade change	Equally spaced apart
		Calibration Curve factor A	0
Calibration Curve factor B	0
		Lower limit of	0.25
Upper limit of	0.5

And saving the screen capturing of the element mapping image which is subjected to the binarization processing in a PNG form. The obtained elemental mapping image of PNG form was analyzed by image analysis software (ImageJ 1.53 e) to determine the average particle size of the nitrides. Specifically, the average particle diameter of the nitride was measured as follows. The elemental mapping image in PNG format was opened with image analysis software (ImageJ 1.53 e). When the nitride is composed of elements a and N (nitrogen), the region of the map Image of the elements a and N is copied at 286×286 pixels and stored as a New (New) Image (Image). The contents of table 7 are input into an Image Calculator (Image Calculator) of Image analysis software (ImageJ 1.53 e) and executed, and a file is created to calculate the locations where both element a and element N are detected.

TABLE 7

Table 7 Image Calculator (Image Calculator)

Imagel	Image file obtained by cutting mapped image of element A
		Operation	And
Image2	Image file obtained by cutting mapping image of element N
		Create new window	Selection of
32-bit(float)result	Non-selection

When the number of elements constituting the nitride is two OR more other than N (nitrogen), the area of the map Image of each element is copied at 286×286 pixels, and after the Image is stored as New Image, the Operation (Operation) in table 7 is set to OR (OR), the map images other than the element N constituting the nitride are selected from the Image1 (Image 1) and the Image2 (Image 2), and all the map images other than the element N constituting the nitride are synthesized by the Image Calculator (Image Calculator). The Image is selected in Image1 of the Image Calculator (Image Calculator) in table 7, and the contents of the Image Calculator (Image Calculator) in table 7 are input and executed in addition to this, and a file is created in which the locations of both elements other than N and element N constituting the nitride are detected.

The obtained file was subjected to black-and-white inversion with Invert, and the contents of Table 8 were entered in a Set scale (Set scale) and executed. Note that, at Known distance, a field of view of each magnification is input. Namely, 900 times input at 100, 180 times input at 500, 90 times input at 1000, 30 times input at 3000, and 10 times input at 10000.

TABLE 8

Table 8 setting proportion (Set scale)

Distance in pixels	286
		Pixel aspect ratio	1.0
Unit of length	μm
		Global	Non-selection

The contents of table 9 are entered in the analysis particles (Analyze particles) and executed. In addition, the values of table 10 were inputted to Size (μm ²) according to the observation magnification.

TABLE 9

Table 9 analysis particle (Analyze particles)

Pixel units	Non-selection
		Circularity	0.00-1.00
Sow	Outlines
		Display results	Selection of
Clear results	Selection of
		Summarize	Selection of
Add to Manager	Non-selection
		Exclude on edges	Selection of
Include holes	Selection of
		Record starts	Non-selection
In situ Show	Non-selection

TABLE 10

Table 10 size (mum ²)

100 Times of	36.36-Infinity
		500 Times	1.46-Infinity
1000 Times	0.37-Infinity
		3000 Times	0.05-Infinity
10000 Times	0.01 To infinity

The Average particle Size (μm) was calculated by the following formula using the Average Size (Average Size) of the Summary screen shown after analysis.

First, the above-described series of analyses was performed on 100-fold images, and when the obtained average particle diameter was equal to or smaller than the criterion of each magnification shown in table 11, the magnifications were increased stepwise in the order of 500-fold, 1000-fold, 3000-fold, and 10000-fold until the average particle diameter became a value larger than the criterion.

TABLE 11

Table 11 determination criterion

[ Relative Density ]

The measurement was performed by the archimedes method using pure water as a displacement liquid. The mass of the sintered body was measured, and the buoyancy (=volume of the sintered body) was measured in a state where the sintered body was suspended in the substitution liquid. The measured density (g/cm ³) was obtained by dividing the mass (g) of the sintered body by the volume (cm ³) of the sintered body. The ratio to the theoretical density calculated based on the composition of the sintered body (measured density/theoretical density) is the relative density.

[ Particle count ]

The sintered body was processed into a back plate having a diameter of 153mm and a thickness of 2mm, and the back plate was bonded to a back plate made of Cu having a diameter of 161mm and a thickness of 4mm with indium to obtain a sputtering target. The sputtering target was mounted on a magnetron sputtering apparatus, and after sputtering under an Ar gas atmosphere having an output of 500W and a gas pressure of 1Pa for 40 seconds, the number of particles adhering to the substrate was measured by a particle counter.

Examples 1 to 26 and comparative examples 1 to 15

Sputtering targets having the designed compositions shown in tables 12 and 13 were produced, and Zr concentration, vickers hardness, average particle diameter of the hard nitride nonmagnetic phase, relative density, and particle number were measured. In the design compositions of tables 12 and 13, fe or Co constitutes the balance, and thus the content representation is omitted. For example, fe-51Pt-7Si ₃N₄ of example 1 means 42Fe-51Pt-7Si ₃N₄.

As the raw material powder of the alloy phase, fe powder having an average particle diameter D50 of 7 μm, co powder having an average particle diameter D50 of 3 μm, and Pt powder having an average particle diameter D50 of 1 μm were used. As additional elements of the alloy phase, cu powder having an average particle diameter D50 of 5 μm, ag powder having an average particle diameter D50 of 4 μm, B powder having an average particle diameter D50 of 8 μm, ge powder having an average particle diameter D50 of 10 μm, cr powder having an average particle diameter D50 of 15 μm, ru powder having an average particle diameter D50 of 13 μm, and Rh powder having an average particle diameter D50 of 13 μm were used.

As the hard nitride powder, si ₃N₄ powder having an average particle diameter D50 of 20 μm, alN powder having an average particle diameter D50 of 8 μm, taN powder having an average particle diameter D50 of 4 μm, cr ₂ N powder having an average particle diameter D50 of 7 μm, nbN powder having an average particle diameter D50 of 10 μm, hfN powder having an average particle diameter D50 of 35 μm, cubic BN powder (cBN) having an average particle diameter D50 of 3 μm, tiN powder having an average particle diameter D50 of 9 μm, VN powder having an average particle diameter D50 of 7 μm were used.

As additional non-magnetic material powders, hexagonal BN powder (BN) having an average particle diameter D50 of 5 μm, B ₂O₃ powder having an average particle diameter D50 of 5 μm, C powder having an average particle diameter D50 of 5 μm, and SiO ₂ powder having an average particle diameter D50 of 1 μm were used.

For examples 1 to 26, the raw material powders were weighed so as to have the designed composition shown in Table 12, and put into a stirring mill together with 4kg of zirconia balls, stirred and mixed at a rotation speed of 100rpm for 4 hours, and the thus obtained mixed powder was sintered at a sintering temperature shown in Table 12 at a sintering pressure of 66 MPa. The hollow column in table 12 indicates that no addition was made.

For comparative examples 1 to 15, the raw material powders weighed so as to have the design composition shown in Table 13 were charged into a stirring mill together with 4kg of zirconia balls, stirred and mixed under stirring conditions shown in Table 13, and the thus obtained mixed powder was sintered at a sintering temperature shown in Table 13 at a sintering pressure of 66 MPa. The hollow column in table 13 indicates that no addition was made.

After measuring the relative density of the obtained sintered body, the sputtering target was processed, and Zr concentration, average particle diameter of hard nitride, vickers hardness, and particle number were measured. The results are shown in tables 14 and 15. The relationship between the Zr concentration and the number of particles is shown in fig. 1, and the relationship between the vickers hardness and the number of particles is shown in fig. 2.

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As is clear from tables 14 to 15 and FIG. 1, the number of particles was as large as 2000 or more at a Zr concentration of 2000ppm or more, but the number of particles was small at a Zr concentration of 1000ppm or less, and particularly the number of particles was as small as 400 or less at a Zr concentration of 300ppm or less. It is also apparent from tables 14 to 15 and fig. 2 that the number of particles is as large as 2000 or more when the vickers hardness Hv is 600 or more, but the number of particles is as small as 400 or less in the range of 200 to 600.

The average particle diameter of the hard nitride particles of the sputtering targets of examples 1 to 26 can be measured at a rate of 500 to 3000, but the average particle diameter of the hard nitride particles of the sputtering targets of comparative examples 1 to 15 needs to be measured at a rate of 10000. As is clear from tables 14 and 15, the average particle diameters of the hard nitrides of examples 1 to 26 were in the range of 1.3 μm to 12.8. Mu.m, and the average particle diameters of the hard nitrides of comparative examples 1 to 15 were fine particles in the range of 0.3 μm to 0.9. Mu.m.

Fig. 3 is an SEM observation photograph (magnification 1000) of the structure of the sputtering target of example 1, fig. 4 is an SEM observation photograph (magnification 1000) of the structure of the sputtering target of example 2, and fig. 5 is an SEM observation photograph (magnification 1000) of the structure of the sputtering target of comparative example 2. The EPMA analysis revealed that the black particles were hard nitride particles and the white to gray particles were alloy phases. As can be seen from a comparison between fig. 3 and 5, the white alloy phase and the black particles of comparative example 2 (fig. 5) are more finely dispersed than those of example 1 (fig. 3). As can be seen from fig. 4, the relatively large hard nitride particles and the alloy phase are homogeneously dispersed.

As is clear from tables 14 to 15 and fig. 3 to 5, the sputtering target produced by the production method of the present invention had larger hard nitride particles than the sputtering target of the comparative example produced by the conventional method, but the nonmagnetic phase and the alloy phase were homogeneously dispersed.

Claims

1. A sputtering target containing a hard nitride, which comprises an alloy phase containing Fe or Co and a non-magnetic phase containing a hard nitride selected from AlN, BN, cr ₂N、Si₃N₄, hfN, nbN, taN, tiN, VN, and any combination thereof,

The Zr impurity concentration when measured as metallic Zr is limited to 1000ppm or less,

The Vickers hardness Hv measured under a load of 3kgf is 200 to 600.

2. The hard nitride-containing sputtering target according to claim 1, wherein the Zr impurity concentration is limited to 500ppm or less.

3. A hard nitride-containing sputtering target according to claim 1 or 2, characterized in that,

The non-magnetic phase satisfies at least one of:

4. A hard nitride-containing sputtering target according to any one of claims 1 to 3, wherein the content of the nonmagnetic phase in the sputtering target is 5mol% or more and 50mol% or less.

5. The sputtering target containing a hard nitride according to any one of claims 1 to 4, wherein the nonmagnetic phase further contains one or more selected from C, B ₂O₃ and SiO ₂.

6. The hard nitride-containing sputtering target according to any one of claims 1 to 5, wherein the alloy phase contains 0mol% or more and 60mol% or less of Pt.

7. The hard nitride-containing sputtering target according to any one of claims 1 to 6, wherein the alloy phase further contains one or more elements selected from Ag, au, cr, cu, ge, ir, ni, pd, rh, ru and B.

8. A method for producing the hard nitride-containing sputtering target according to any one of claims 1 to 7, comprising:

Mixing raw material powders constituting the alloy phase and the nonmagnetic phase at a rotation speed of 50rpm or more and 150rpm or less using a zirconia ball mill for 2 hours or more and 6 hours or less to prepare a mixed powder,

Sintering the mixed powder.

9. The method for producing a sputtering target containing a hard nitride according to claim 8, wherein the raw material powder constituting the alloy phase is a metal powder of each raw material or an atomized alloy powder of Fe-based or Co-based.

10. The method according to claim 8 or 9, wherein the raw material powder constituting the nonmagnetic phase contains a hard nitride powder having an average particle diameter D50 of 1 μm or more and 40 μm or less.