TW202206628A - Sputtering target and method for manufacturing same - Google Patents

Abstract

The purpose of the present disclosure is to provide: a sputtering target that enables obtaining of a uniform compositional distribution in the in-plane direction and in the film thickness direction regarding the compositional makeup of a deposited film; and a method for manufacturing the sputtering target. The sputtering target according to the present invention is an alloy formed from a first element which is ruthenium and a second element which is one selected from among boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten. The sputtering target includes dispersed particles each formed from two phases including an inter metal compound phase comprising the two types of elements which are the first element and the second element. The maximum major axis of the dispersed particles is not more than 500 [mu]m.

Description

Sputtering target and method for producing the same

The present invention relates to a sputtering target, which is suitable for forming a protective film of a mask blank, ie, a mask blank used in EUV lithography using extreme ultraviolet (Extreme Ultra Violet: hereinafter referred to as EUV) light, or for forming a mask blank. A mask film that prevents foreign matter from adhering to the pattern surface of the mask, etc.

Regarding semiconductor devices, the industry requires miniaturization of the electronic circuits constituting the IC (integrated circuit) chips of electronic components, so EUV lithography and other technologies are being used to form fine circuit patterns, but the manufacturing process is about several nanometers. Defects such as fine dust or flaws will become fatal defects in the action, so the material of the film used in the mask original, that is, the blank mask, also becomes more important.

Regarding the EUV-oriented thin film called a mask substrate or a mask film, in consideration of the transmission or absorption of EUV light and the advantages in thermal conductivity, an alloy material added to ruthenium is used to form a thin film by sputtering. method to form a thin film.

As a sputtering target used in the manufacture of a reflective blank mask for EUV lithography, a sputtering target comprising a ruthenium compound is proposed, the ruthenium compound containing ruthenium and a material selected from the group consisting of niobium, molybdenum, zirconium, titanium, lanthanum , at least one of silicon, boron, and yttrium (for example, refer to Patent Document 1). According to Patent Document 1, the content of niobium, molybdenum, zirconium, titanium, lanthanum, and silicon in the compound is preferably in the range of 3 to 75 atomic %, and in particular, from the viewpoint of improving the chemical resistance, it is preferably 40 atomic %. ~75 atomic % range. In addition, according to Patent Document 1, boron and yttrium are metals that are easily oxidized. Therefore, if the content of these metals is high, an oxide layer is formed on the surface of the ruthenium compound film to be formed, which has optical properties. (For example, the reflectance of EUV light) may deteriorate, so the content of boron and yttrium in the compound is preferably in the range of 3 to 50 atomic %. In addition, according to Patent Document 1, among impurities, the content of oxygen, especially, the content of oxygen is 2000 ppm or less, and the content of carbon is 200 ppm or less, so that the content of both oxygen and carbon is reduced, thereby reducing the content of oxygen and carbon generated by the target during film formation. Particle reduction.

Patent Document 1: Japanese Patent Laid-Open No. 2006-283054

[Problems to be Solved by Invention]

However, if particles causing defects in the film are generated during film formation, the particles adhere to the film and cause defects, thereby causing a decrease in film yield. The problem of particle attachment to the film is extremely important due to the patterning on the mask substrate to design the semiconductor design. Regarding the photomask protective film, the transmittance of EUV light in the particle-attached part is also reduced, which will affect the transfer of the circuit, resulting in a decrease in yield. There are many factors for the generation of particles in the film formation. The causes of particles generated by the target include: the arc effect caused by the voids formed by the poor density, or the arc effect generated by the oxide on the surface of the target material.

In addition, when it is a photomask substrate or a photomask protective film, the film thickness of the film formed is extremely thin, and the range of the film formed is relatively wide, so the in-plane uniformity and composition of the film thickness in the film surface In-plane uniformity becomes more important. Therefore, sputtering targets have been required to increase the density of the target and reduce the oxygen content. However, recently, with the formation of fine circuit patterns, the particles causing defects tend to be smaller, so not only the origin of the particles is speculated, but also the material added to the ruthenium itself is suspected to be scattered during the film formation process.

In order to reduce the oxygen content or increase the density, sputtering targets have been produced by a melting method. However, most of ruthenium and these added elements are high melting point materials with a melting point exceeding 1600° C. and are not easily melted. Furthermore, ruthenium and additional elements form various intermetallic compounds (hereinafter referred to as IMC), so cracks are likely to occur during the solidification process. If processing is performed after melting and solidification, cracks will occur. Therefore, it is difficult to form the target material. Big. For example, although the target has been successfully formed, IMC will precipitate and coarsen during the solidification process, and the composition distribution in the target in-plane direction and the cross-sectional direction (also called the target thickness direction) will deteriorate, so sputtering The sputtering rate varies depending on the position in the target material, and the uniformity of the in-plane composition distribution and film thickness distribution of the formed film is deteriorated. In order to refine the structure, the target is generally hot-worked, but the IMC is precipitated and coarsened to cause cracks or cracks, so hot-working cannot be performed.

In order to make the additive elements highly dispersed in the target, there is also a method of sintering. The more finely powdered the additive element is, the easier it is to disperse in the target. However, if it is an additive element with a very high activity, it may cause a fire, so it is difficult to handle the fine powder. In addition, even if it is a stable additive element, the finer the powder, the larger the specific surface area, and the easier the oxidation progresses, so the oxygen content of the target material increases. Therefore, a powder having a relatively coarse particle size has to be used, but in order to make it highly dispersed, it is necessary to perform a mixing treatment with high energy or the like. However, large-scale atmosphere control is required in order to suppress the oxidation of the added elements, or it may lead to contamination (contamination) of impurities from the medium used for mixing, so the above-mentioned relatively coarse powder is not suitable for EUV-oriented sputtering which requires high purity target.

Therefore, an object of the present invention is to provide a sputtering target and a method for producing the same, wherein the composition of the formed film of the sputtering target can obtain a uniform composition distribution both in the in-plane direction of the film and in the film thickness direction. [Technical means to solve problems]

The inventors of the present invention have made intensive studies in order to solve the above-mentioned problems, and as a result, they have found that by setting the long diameter of the dispersed particles in the sputtering target to a specific particle diameter, the composition of the formed film can be made in the in-plane direction of the film and A uniform composition distribution can be obtained in the film thickness direction, thereby completing the present invention. That is, the sputtering target material of the present invention contains ruthenium as the first element, and contains any one selected from the group consisting of boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten as the second element The alloy sputtering target is characterized in that: the sputtering target has dispersed particles including two phases, the two phases include an intermetallic compound phase, and the intermetallic compound phase includes two of the first element and the second element. element, and the maximum major diameter of the dispersed particles is 500 μm or less. By making the particle size into a specific particle size, the particles can be highly dispersed in the sputtering target, so that the composition of the film formed by using the above-mentioned target can be uniform in both the in-plane direction of the film and the film thickness direction. composition distribution.

The sputtering target of the present invention includes the following forms: the two phases are (1) a combination of the intermetallic compound phase and the metal phase of the first element, that is, a metal ruthenium phase; (2) a combination of the two intermetallic compound phases; Or (3) a combination of the above-mentioned intermetallic compound phase and the above-mentioned metal phase of the second element.

The sputtering target of the present invention is an alloy containing ruthenium as the first element and any one selected from the group consisting of boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten as the second element The sputtering target is characterized in that: the sputtering target has dispersed particles including an intermetallic compound phase, the intermetallic compound phase includes two elements of the first element and the second element, and the maximum length of the dispersed particles is The diameter is 500 μm or less, and under (Condition 1) or (Condition 2), there is at least one location obtained by X-ray diffraction of the sputtering target in the sputtering in-plane direction The relative integrated intensity of the second peak is more than 60% of the relative integrated intensity of the first peak, (Condition 1) In-plane direction of sputtering: The sputtering target is a disk-shaped target with a center O and a radius r, and the measurement site is set to a total of 9 sites, that is, a virtual cross orthogonal to the center O as an intersection On the line, 1 site at the center O, a total of 4 sites with a distance of 0.45r from the center O, and a total of 4 sites with a distance of 0.9r from the center O; (Condition 2) In-plane direction of sputtering: the above-mentioned sputtering target is a rectangle with a vertical length L1 and a horizontal length L2 (including a square with equal L1 and L2; or a rectangle including a cylindrical side with a length J and a perimeter K The rectangle formed after expansion, in this form, L2 corresponds to length J, L1 corresponds to perimeter K, and between length J and perimeter K, the relationship of J>K, J=K or J<K is established), And the measurement site is set to a total of 9 sites, that is, when the virtual cross line orthogonal to the center of gravity O is perpendicular to the side of the rectangle, one site of the center of gravity O, on the virtual cross line and the center of gravity O are at right angles to each other. A total of 2 locations with a distance of 0.25L1 in the longitudinal direction, a total of 2 locations with a distance of 0.25L2 from the center of gravity O in the transverse direction, a total of 2 locations with a distance of 0.45L1 from the center of gravity O in the longitudinal direction, and a distance from the center of gravity O in the transverse direction by 0.45 A total of 2 parts of L2. The difference between the relative integrated intensity of the second peak and the relative integrated intensity of the first peak is reduced, and the degree of anisotropy of the structure is reduced, thereby suppressing the difference in sputtering rate during film formation, and obtaining a uniform film thickness .

In the sputtering target of the present invention, under (Condition 1) or (Condition 2), it is preferable that 40% or more of the following portion is present, and this portion is the in-plane direction of the sputtering target by X The relative integrated intensity of the second peak obtained by ray diffraction is more than 60% of the relative integrated intensity of the first peak. By the existence of a large number of regions where the difference between the relative integrated intensity of the second peak and the relative integrated intensity of the first peak is small, the degree of anisotropy of the structure is reduced, thereby suppressing the difference in sputtering rate during film formation, and A uniform film thickness can be obtained.

In the sputtering target of the present invention, the difference between the composition of the sputtering target in (condition 3) or (condition 4) in the sputtering in-plane direction and in the thickness direction of the target and the reference composition is preferably ±1.5 Within %, the above reference composition is the average value of the composition of a total of 18 parts measured according to (Condition 3) or (Condition 4). (Condition 3) In-plane direction of sputtering: The sputtering target is a disk-shaped target with a center O and a radius r, and the measurement site is set to a total of 9 sites, that is, a virtual cross orthogonal to the center O as an intersection On the line, one site at the center O, a total of 4 sites at a distance of 0.45r from the center O, and a total of 4 sites at a distance of 0.9r from the center O. The thickness direction of the target material: form a cross-section passing through any line in the virtual cross line, and the cross-section is a rectangle with a vertical t (that is, the thickness of the target is t) and a horizontal 2r, and for the measurement site, the following 9 sites in total are set. It is the measurement point, that is, the center X on the vertical intersecting line passing through the center O and the total of 3 points (called a point, X point, and b point) that are 0.45t away from the center X in the upper and lower sides. A total of 2 locations with a left and right side distance of 0.9r, a total of 2 locations from the X point to a left and right side distance of 0.9r, and a total of 2 locations from the b point to a left and right side distance of 0.9r. (Condition 4) In-plane direction of sputtering: the above-mentioned sputtering target is a rectangle with a vertical length L1 and a horizontal length L2 (including a square with equal L1 and L2; or a rectangle including a cylindrical side with a length J and a perimeter K The rectangle formed after expansion, in this form, L2 corresponds to length J, L1 corresponds to perimeter K, and between length J and perimeter K, the relationship of J>K, J=K or J<K is established), And the measurement site is set to a total of 9 sites, that is, when a virtual cross line orthogonal to the center of gravity O is perpendicular to the side of the rectangle, one site of the center of gravity O is on the virtual cross line and the center of gravity O is in the vertical direction. A total of 2 locations with a distance of 0.25L1 from the center of gravity O, a total of 2 locations with a distance of 0.25L2 from the center of gravity O in the horizontal direction, a total of 2 locations with a distance of 0.45L1 from the center of gravity O in the vertical direction, and a distance from the center of gravity O in the horizontal direction by 0.45L2 2 parts in total. The thickness direction of the target material: form a cross-section through a line parallel to any one of the vertical L1 and the horizontal L2 in the virtual cross line. When one side is the horizontal L2, the cross-section is the vertical t (that is, the thickness of the above-mentioned target material is t ), a rectangle of horizontal L2, and for the measurement site, a total of 9 sites are set as the measurement site, that is, a total of 3 sites ( Referred to as point a, point X, point b), on the above-mentioned cross-section from point a toward the left and right sides with a distance of 0.45L2 in total, 2 points in total with a distance of 0.45L2 from the X point to the left and right sides, and from b The location is oriented to a total of 2 parts with a distance of 0.45L2 between the left and right sides. By suppressing the variation in the composition of the target material and suppressing the difference in the sputtering rate during film formation, the variation in the composition and thickness of the film after film formation can be suppressed. In addition, it is possible to suppress the contamination of particles caused by minute protrusions generated by differences in sputtering rates.

In the sputtering target of the present invention, the crystallite size of the first peak is preferably 400 Å or less. By reducing the crystallite size, a homogeneous thin film can be formed.

In the sputtering target of the present invention, the content of the second element is preferably 3 to 70 atomic %. Regarding the composition of the film to be formed, the reflectance required for EUV can be secured while the corrosion resistance is improved.

The sputtering target of the present invention preferably has an oxygen content of 500 ppm or less. By suppressing the bond between oxygen and the second element to form the oxide of the second element in the sputtering target, abnormal discharge caused by the oxide of the second element can be suppressed, thereby suppressing the generation of particles.

The sputtering target of the present invention preferably has a carbon content of 200 ppm or less. By suppressing the bonding of carbon and the second element to form carbides of the second element in the sputtering target, abnormal discharge caused by the carbides of the second element can be suppressed, thereby suppressing the generation of particles.

The method for producing a sputtering target of the present invention is characterized by comprising: a preparation step of preparing a raw material in which the first element and the second element are in a specific element ratio; an atomization step of 1×10 ^-2 Pa In the following vacuum atmosphere, a nitrogen atmosphere containing 0-4 vol% or less of hydrogen, or an inert gas atmosphere containing 0-4 vol% or less of hydrogen, the above-mentioned raw materials are used to obtain alloy powder by atomization; and the sintering step, It uses hot pressing method (HP), spark plasma sintering method (SPS) or hot isostatic pressing sintering method (HIP), in a vacuum atmosphere of 50 Pa or less, a nitrogen atmosphere containing 0-4 vol% or less of hydrogen, or a The sintered body is obtained by sintering the above-mentioned alloy powder in an inert gas atmosphere of 0-4 vol% or less of hydrogen; and the maximum long diameter of the alloy powder obtained by the above-mentioned atomization method is 500 μm or less. Oxidation or carbonization of the additive elements can be suppressed and dispersed in the sputtering target, so the composition of the film formed by using the above-mentioned target can suppress the mixing of particles, and the in-plane direction and film thickness of the film can be suppressed. A uniform composition distribution can be obtained in all directions.

Preferably, the method for producing a sputtering target of the present invention further includes, between the atomization step and the sintering step, a classification step for removing the maximum length of the alloy powder obtained by the atomization method. Particles over 500 μm in diameter. In the step of obtaining the sintered body, a sputtering target with a high density can be formed, so the composition of the film obtained by using the above-mentioned target for film formation can be uniform in the in-plane direction and the film thickness direction of the film. . [Effect of invention]

The present invention can provide a sputtering target material and a method for producing the same. The composition of the film formed by the sputtering target material can obtain uniform composition distribution in the in-plane direction and the film thickness direction of the film.

Hereinafter, the present invention will be described in detail by showing the embodiments of the present invention, but the present invention is not limited to these descriptions and is not construed. Various changes can be made to the embodiment as long as the effects of the present invention are exhibited.

The sputtering target material of this embodiment contains ruthenium as the first element, and contains any one selected from the group consisting of boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten as the second element. Alloy sputtering target, and the sputtering target has dispersed particles including two phases, the two phases include an intermetallic compound phase, and the intermetallic compound phase includes two elements of the above-mentioned first element and the above-mentioned second element; Dispersed particles The maximum long diameter is 500 μm or less. Regarding the dispersed particles present in the sputtering target, for example, when the sputtering target is a sintered body, the dispersed particles correspond to the constituent particles of the sintered body. The dispersed particles have a plurality of crystal grains.

The maximum major diameter of the dispersed particles is 500 μm or less, preferably 250 μm or less, more preferably 200 μm or less, and still more preferably 150 μm or less. If the maximum long diameter of the dispersed particles is larger than 500 μm, the dispersed particles will be biased in the sputtering target, and the composition will vary depending on the position of the sputtering target. When a film is formed using a sputtering target having a compositional variation, compositional variation also occurs in the in-plane direction and the film thickness direction of the film, so it is preferable that the maximum long diameter of the dispersed particles is 500 μm or less. Here, setting the maximum major diameter to 500 μm or less means that particles having a major diameter exceeding 500 μm are not contained. Furthermore, the determination of the maximum long diameter is carried out in the following manner, that is, in the range of 1200 μm×1500 μm, according to the image analysis of SEM (scanning electron microscope, scanning electron microscope), the largest dispersed particle is measured based on the scale of the image. The distance from one end to the other.

The sputtering target of this embodiment includes the following forms: the two phases are (1) a combination of an intermetallic compound phase and a metal phase of the first element, that is, a metallic ruthenium phase, (2) a combination of two intermetallic compound phases, or (3) ) The combination of the intermetallic compound phase and the metal phase of the second element. In this embodiment, the number of phases is determined by the phases identified by X-ray diffraction. In addition, the intermetallic compound formed in the grain boundary is excluded from the object of the two phases. The dispersed particles have two kinds of grains corresponding to two.

The grain boundary includes: the boundary between the dispersed particle and the dispersed particle adjacent to the dispersed particle, and the boundary between the crystal grain and the crystal grain adjacent to the crystal grain.

For example, in the case where the types of intermetallic compounds are Ru ₂ AE, RuAE and RuAE ₂ , for "the two phases are (1) the combination of the intermetallic compound phase and the metal phase of the first element, that is, the metal ruthenium phase", "two phases" (2) Combination of two intermetallic compound phases" and "The two phases are (3) Combination of an intermetallic compound phase and a metal phase of the second element" will be described. In this case, the forms of the phases that appear are: a form of only metal ruthenium phase (which contains a solid solution in which the second element is dissolved in ruthenium); a Ru phase (which contains the second element in a solid solution in ruthenium). The form of Ru _{2 AE phase, Ru AE phase and Ru AE 2 phase; the form of Ru 2 AE phase only; the form of Ru 2 AE phase and RuAE phase; the form of Ru 2 AE phase and Ru} AE phase The form of RuAE ₂ phase; the form of RuAE phase only; the form of RuAE phase and RuAE ₂ phase; the form of RuAE ₂ phase only; any one of RuAE ₂ phase, RuAE phase and Ru ₂ AE phase and AE phase (wherein, A form containing ruthenium in a solid solution of the second element); and a form of a metal phase containing only the second element (including a solid solution in which ruthenium is dissolved in the second element). Here, "two phases are (1) a combination of an intermetallic compound phase and a metal phase of the first element, that is, a metallic ruthenium phase" refers to the form of a Ru phase and any one of the Ru ₂ AE phase, the RuAE phase, and the RuAE ₂ phase. . In addition, "two phases are (2) a combination of two intermetallic compound phases" means the form of Ru ₂ AE phase and RuAE phase, the form of Ru ₂ AE phase and RuAE ₂ phase, or the form of RuAE phase and RuAE ₂ phase . Furthermore, "the two phases are (3) the combination of the intermetallic compound phase and the metal phase of the second element" refers to the form of any one of the RuAE ₂ phase, the RuAE phase, and the Ru ₂ AE phase and the AE phase. When the types of intermetallic compounds are two or four or more cases, the cases can also be classified according to the same idea.

The reason for the appearance of two phases is the two kinds of crystallites with different compositions in the dispersed particles. The case where the types of the intermetallic compounds are Ru ₂ AE, RuAE, and RuAE ₂ is exemplified for description. When "the two phases are (1) the combination of the intermetallic compound phase and the metal phase of the first element, that is, the metal ruthenium phase", any of the Ru phase crystal grains and the Ru ₂ AE phase, the RuAE phase and the RuAE ₂ phase exist in the dispersed particles. A phase grain. In addition, "two phases are (2) a combination of two intermetallic compound phases" refers to the following forms: the crystal grains of Ru ₂ AE phase and the crystal grains of RuAE phase exist in the dispersed particles; Ru ₂ exists in the dispersed particles. The grains of the AE phase and the grains of the RuAE ₂ phase; or the grains of the RuAE phase and the grains of the RuAE ₂ phase in the dispersed particles. Further, "the two phases are (3) the combination of the intermetallic compound phase and the metal phase of the second element" means that the crystal grains of any one of the RuAE ₂ phase, the RuAE phase and the Ru ₂ AE phase exist in the dispersed particles and the The shape of the grains of the AE phase. When the types of intermetallic compounds are two or four or more cases, the cases can also be classified according to the same idea.

The sputtering target material of this embodiment contains ruthenium as the first element, and contains any one selected from the group consisting of boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten as the second element. Alloy sputtering target, and the sputtering target has dispersed particles containing an intermetallic compound phase, the intermetallic compound phase contains two elements of the above-mentioned first element and the above-mentioned second element; the maximum long diameter of the dispersed particles is 500 μm Hereinafter, under (Condition 1) or (Condition 2), there is at least one location which is the relative integral of the second peak obtained by X-ray diffraction of the sputtering target in the sputtering in-plane direction The intensity is more than 60% of the relative integrated intensity of the first peak. The first peak refers to the peak with the highest height among the peaks derived from the alloy of the first element and the second element which appear as CuKα rays in the range of 2θ=20 to 90° in the X-ray diffraction spectrum. The second peak refers to the peak with the second highest height among the peaks derived from the alloy of the first element and the second element which appear as CuKα rays in the range of 2θ=20 to 90° in the X-ray diffraction spectrum. (Condition 1) In-plane direction of sputtering: The sputtering target is a disk-shaped target with a center O and a radius r, and the measurement site is set to a total of 9 sites, that is, a virtual cross orthogonal to the center O as an intersection On the line, one site at the center O, a total of 4 sites at a distance of 0.45r from the center O, and a total of 4 sites at a distance of 0.9r from the center O. (Condition 2) In-plane direction of sputtering: the above-mentioned sputtering target is a rectangle with a vertical length L1 and a horizontal length L2 (including a square with equal L1 and L2; or a rectangle including a cylindrical side with a length J and a perimeter K developed The rectangle formed later, in this form, L2 corresponds to length J, L1 corresponds to perimeter K, and between length J and perimeter K, the relationship of J>K, J=K or J<K is established), and The measurement site is set to a total of 9 sites, that is, when a virtual cross line orthogonal to the center of gravity O is perpendicular to the sides of the rectangle, one site of the center of gravity O, on the virtual cross line, and the center of gravity O are in the longitudinal direction. A total of 2 locations with a distance of 0.25L1, a total of 2 locations with a distance of 0.25L2 from the center of gravity O in the horizontal direction, a total of 2 locations with a distance of 0.45L1 from the center of gravity O in the vertical direction, and a distance from the center of gravity O in the horizontal direction by 0.45L2 2 parts in total.

In X-ray diffraction, under (Condition 1) or (Condition 2), the measurement range of the nine parts is preferably 10 mm×10 mm, respectively. Regarding the determination that the relative integrated intensity of the second peak obtained by X-ray diffraction of the sputtering target in the sputtering in-plane direction is 60% or more of the relative integrated intensity of the first peak, it is carried out as follows: From the graph obtained by X-ray diffraction, screen the first peak and the second peak, and use the X-ray diffraction waveform analysis software to calculate the relative integrated intensity of the first peak and the relative integrated intensity of the second peak, and determine the relative integral of the second peak. Whether the intensity is more than 60% of the relative integrated intensity of the first peak.

The relative integrated intensity of the second peak obtained by X-ray diffraction of the sputtering target in the sputtering surface direction is 60% or more, preferably 65% or more, more preferably 70% of the relative integrated intensity of the first peak. %above. Under (Condition 1) or (Condition 2), if the relative integrated intensity of the second peak under X-ray diffraction is less than 60% of the relative integrated intensity of the first peak, the film thickness of the formed film will be uneven, so it is relatively It is preferable that the relative integrated intensity of the second peak under X-ray diffraction be 60% or more of the relative integrated intensity of the first peak.

In the sputtering target of the present embodiment, under (Condition 1) or (Condition 2), 40% or more of the following portion is preferably present, and this portion is the passage of the sputtering target in the in-plane direction of the sputtering surface. The relative integrated intensity of the second peak obtained by X-ray diffraction is more than 60% of the relative integrated intensity of the first peak; more preferably, there is more than 50% of the part. By the existence of a large number of regions where the difference between the relative integrated intensity of the second peak and the relative integrated intensity of the first peak is small, the degree of anisotropy of the structure is reduced, thereby suppressing the difference in sputtering rate during film formation, and A uniform film thickness can be obtained. Under (Condition 1) or (Condition 2), "there is 40% or more of the following portion, which is the second peak obtained by X-ray diffraction of the sputtering target in the sputtering surface direction. The relative integrated intensity is 60% or more of the relative integrated intensity of the first peak" means the following cases: under (Condition 1) or (Condition 2), when there are 9 measurement locations, respectively, it is classified into "sputtering target material and sputtering In the in-plane direction, the relative integrated intensity of the second peak obtained by X-ray diffraction is 60% or more of the relative integrated intensity of the first peak. The part where the relative integrated intensity of the second peak obtained by X-ray diffraction does not reach 60% of the relative integrated intensity of the first peak", as long as there are 4 or more out of 9 parts "the sputtering target is in the in-plane direction of the sputtering surface" The part where the relative integrated intensity of the second peak obtained by X-ray diffraction is more than 60% of the relative integrated intensity of the first peak”, which satisfies “there is more than 40% of the following parts, and this part is a sputtering target. The relative integrated intensity of the second peak obtained by X-ray diffraction in the sputtering in-plane direction is 60% or more of the relative integrated intensity of the first peak."

In the sputtering target of the present embodiment, the difference between the composition of the sputtering target in (condition 3) or (condition 4) in the sputtering in-plane direction and in the thickness direction of the target and the reference composition is preferably ±1.5 Within %, the reference composition is the average value of the composition of a total of 18 parts measured according to (Condition 3) or (Condition 4). (Condition 3) In-plane direction of sputtering: The sputtering target is a disk-shaped target with a center O and a radius r, and the measurement site is set to a total of 9 sites, that is, a virtual cross orthogonal to the center O as an intersection On the line, one site at the center O, a total of 4 sites at a distance of 0.45r from the center O, and a total of 4 sites at a distance of 0.9r from the center O. The thickness direction of the target material: form a cross-section passing through any line in the virtual cross line, and the cross-section is a rectangle with a vertical t (that is, the thickness of the target is t) and a horizontal 2r, and for the measurement site, the following 9 sites in total are set. It is the measurement point, that is, the center X on the vertical intersecting line passing through the center O and the total of 3 points (called a point, X point, and b point) that are 0.45t away from the center X in the upper and lower sides. A total of 2 locations with a left and right side distance of 0.9r, a total of 2 locations from the X point to a left and right side distance of 0.9r, and a total of 2 locations from the b point to a left and right side distance of 0.9r. (Condition 4) In-plane direction of sputtering: the above-mentioned sputtering target is a rectangle with a vertical length L1 and a horizontal length L2 (including a square with equal L1 and L2; or a rectangle including a cylindrical side with a length J and a perimeter K developed The rectangle formed later, in this form, L2 corresponds to length J, L1 corresponds to perimeter K, and between length J and perimeter K, the relationship of J>K, J=K or J<K is established), and The measurement site is set to a total of 9 sites, that is, when a virtual cross line orthogonal to the center of gravity O is perpendicular to the sides of the rectangle, one site of the center of gravity O, on the virtual cross line, and the center of gravity O are in the longitudinal direction. A total of 2 locations with a distance of 0.25L1, a total of 2 locations with a distance of 0.25L2 from the center of gravity O in the horizontal direction, a total of 2 locations with a distance of 0.45L1 from the center of gravity O in the vertical direction, and a distance from the center of gravity O in the horizontal direction by 0.45L2 2 parts in total. The thickness direction of the target material: form a cross-section through a line parallel to any one of the vertical L1 and the horizontal L2 in the virtual cross line. When one side is the horizontal L2, the cross-section is the vertical t (that is, the thickness of the above-mentioned target material is t ), a rectangle of horizontal L2, and for the measurement site, a total of 9 sites are set as the measurement site, that is, a total of 3 sites ( Referred to as point a, point X, point b), on the above-mentioned cross-section from point a toward the left and right sides with a distance of 0.45L2 in total, 2 points in total with a distance of 0.45L2 from the X point to the left and right sides, and from b The location is oriented to a total of 2 parts with a distance of 0.45L2 between the left and right sides.

In the sputtering target of the present embodiment, the difference between the composition of the sputtering target in (condition 3) or (condition 4) in the sputtering in-plane direction and in the thickness direction of the target and the reference composition is preferably within ± Within 1.5%, more preferably within ±1.25%, and still more preferably within ±1%. The reference composition is the average value of the composition of a total of 18 parts measured according to (condition 3) or (condition 4). If the difference from the standard composition is more than ±1.5%, the compositional deviation will increase depending on the position of the sputtering target. Therefore, when a film is formed using a sputtering target having a compositional deviation, the surface of the film will be Since the composition varies in the direction and the film thickness direction, it is preferable that the difference between the composition of the sputtering target in the sputtering in-plane direction and the thickness direction of the target and the reference composition is within ±1.5%.

Regarding the composition, in (Condition 3) or (Condition 4), the measurement range of the nine sites is preferably 700 μm×900 μm, respectively.

FIG. 1 is a schematic diagram showing a measurement site (hereinafter, also simply referred to as a measurement site) of a disk-shaped target in the in-plane direction of sputtering. Referring to FIG. 1 , the sputtering targets of (Condition 1) and (Condition 3) The measurement site in the sputtering in-plane direction will be described. In the case of a disk-shaped target, the radius is preferably 25-225 mm, more preferably 50-200 mm. The thickness of the target material is preferably 3-30 mm, more preferably 5-26 mm. In this embodiment, a better effect can be expected for a large target.

In FIG. 1, the sputtering target 200 is a disk-shaped target with a center O and a radius r. The measurement sites are set to a total of 9 sites, that is, one site (S1) of the center O, and a total of 4 sites that are 0.45r away from the center O on the virtual cross line (L) orthogonal to the center O as the intersection point. Parts (S3, S5, S6 and S8), and a total of four parts (S2, S4, S7 and S9) at a distance of 0.9r from the center O.

FIG. 2 is a schematic view showing the measurement position of the disk-shaped target in the target thickness direction shown in the BB cross section of FIG. 1 . Referring to FIG. 2 , the sputtering target of (Condition 3) is in the target thickness direction. The measurement site will be described.

In FIG. 2, the section B-B in FIG. 1 is a rectangle with a vertical t (that is, the thickness of the target is t) and a horizontal 2r. In addition, as for the measurement site, a total of 9 sites, that is, the center X (C1) on the vertical intersecting line passing through the center O shown in FIG. (called a point (C4), X point (C1), b point (C5)), a total of 2 points (C6, C7) with a distance of 0.9r from point a to the left and right sides on the above cross section (C6, C7), A total of 2 sites (C2, C3) with a left and right side spacing of 0.9r from the point X, and a total of 2 sites (C8, C9) with a left and right side spacing of 0.9r from the b point.

FIG. 3 is a schematic view showing the measurement position of the square plate-shaped target in the sputtering in-plane direction. Referring to FIG. 3 , the sputtering targets of (Condition 2) and (Condition 4) are in the sputtering in-plane direction. The measurement site will be described. In the case of a rectangular or square target, the vertical and horizontal lengths are preferably 50 to 450 mm, more preferably 100 to 400 mm. The thickness of the target material is preferably 3-30 mm, more preferably 5-26 mm. In this embodiment, a better effect can be expected for a large target.

The sputtering target 300 is a rectangular target with a vertical length L1 and a horizontal length L2 (including a square where L1 and L2 are equal). In FIG. 3 , the sputtering target 300 is shown in the form of L1=L2 . The measurement site is set to a total of 9 sites, that is, when the virtual cross (Q) orthogonal to the center of gravity O is perpendicular to the side of the rectangle (or square), one site (P1) of the center of gravity O, on the The virtual reticle and the center of gravity O are 0.25L1 apart in the vertical direction (P6, P8), and the total 2 parts (P3, P5) are 0.25L2 away from the center of gravity O in the horizontal direction, and the center of gravity O is vertically separated A total of 2 sites (P7, P9) of 0.45L1, and a total of 2 sites (P2, P4) separated from the center of gravity O by 0.45L2 in the lateral direction. Furthermore, when the sputtering target is a rectangle, L1 and L2 can be appropriately selected regardless of the side length.

FIG. 4 is a schematic diagram showing the measurement position of the square plate-shaped target in the target thickness direction shown in the CC cross section of FIG. 3 . Referring to FIG. 4 , the sputtering target of (Condition 4) is in the target thickness direction. The measurement site above will be described.

In FIG. 4, the CC cross section of FIG. 3 is a cross section passing through a line parallel to the horizontal side, and the cross section is a rectangle with a vertical t (that is, the thickness of the target material is t) and a horizontal L2, and for the measurement site, the following A total of 9 points are set as measurement points, that is, a total of 3 points (called a point (D4), X point (D1), b Point (D5)), on the above cross-section from point a to the left and right sides with a distance of 0.45L2 in total (D6, D7), from the X point to a total of 2 points with a left and right side distance of 0.45L2 (D2, D3 ), and a total of 2 parts (D8, D9) with a distance of 0.45L2 from the point b to the left and right sides.

(Cylinder-shaped sputtering target) FIG. 5 is a conceptual diagram for explaining the measurement site of the cylindrical target. When the sputtering target is in the shape of a cylinder, the side surface of the cylinder is the sputtering surface, and the developed view is a rectangle (including a square), so about (Condition 2) or (Condition 4), it can be considered that it is the same as FIG. 3 and FIG. 3 . 4 is the same. If it is a rectangle, it includes a rectangle formed by unfolding the cylindrical sides of length J and perimeter K. In this form, L2 corresponds to length J, L1 corresponds to perimeter K, and the difference between length J and perimeter K is , the relationship of J>K, J=K or J<K is established. In FIG. 5 , when the sputtering target 400 has a cylindrical shape with a height (length) J and a perimeter K of the main body, the E-E cross section and the D-D development plane at both ends are considered. First, the measurement site in the thickness direction of the target material is considered to be the same as in FIG. 4 in the E-E cross section. That is, it is considered that the height J of the cylindrical material corresponds to L2 in FIG. 4 , and the thickness of the cylindrical material corresponds to the thickness t in FIG. 4 , and the measurement site is set. In addition, regarding the measurement site|part in the sputtering in-plane direction, it is considered that it is the same as that of FIG. 3 in the D-D development plane. That is, it is assumed that the height J of the cylindrical material corresponds to L2 in FIG. 3 , and the circumference K of the main body of the cylindrical material corresponds to L1 in FIG. 3 , and the measurement site is set. In the case of a cylindrical target, the length of the circumference of the cylinder is preferably 100 to 350 mm, more preferably 150 to 300 mm. The length of the cylinder is preferably 300-3000 mm, more preferably 500-2000 mm. The thickness of the target material is preferably 3-30 mm, more preferably 5-26 mm. In this embodiment, a better effect can be expected for a large target.

In the sputtering target of the present embodiment, the crystallite size of the first peak is preferably 400 Å or less, more preferably 350 Å or less, and still more preferably 300 Å or less. If the crystallite size of the first peak is larger than 400 Å, the alignment of crystallites will be biased, so the sputtering rate will vary according to different parts, resulting in a difference in film thickness. Therefore, it is better to make the crystallite size of the first peak. become below 400 Å. The measurement method of the crystallite size is to measure the crystallite size using the waveform analysis software of X-ray diffraction.

In the sputtering target of the present embodiment, the content of the second element is preferably 3 to 70 atomic %, more preferably 5 to 65 atomic %, and still more preferably 10 to 60 atomic %. If the content is less than 3 atomic %, the reflectance of the film cannot be improved when a target is used to form a thin film, and if the content is more than 70 atomic %, there will be less ruthenium, which leads to a decrease in chemical resistance, even if the target is used Since it is difficult to use a film even if the material is formed into a film, the content is preferably 3 to 70 atomic %.

The content of boron is preferably 25 to 65 atomic %, more preferably 30 to 60 atomic %. The content of aluminum is preferably 20 to 60 atomic %, more preferably 30 to 55 atomic %. The content of titanium is preferably 10 to 65 atomic %, more preferably 25 to 50 atomic %. The content of zirconium is preferably 15 to 65 atomic %, more preferably 20 to 50 atomic %. The content of hafnium is preferably 15 to 65 atomic %, more preferably 20 to 50 atomic %. The content of vanadium is preferably 35 to 65 atomic %, more preferably 40 to 60 atomic %. The content of niobium is preferably 15 to 60 atomic %, more preferably 20 to 50 atomic %. The content of tantalum is preferably 10 to 65 atomic %, more preferably 25 to 40 atomic %. The content of chromium is preferably 30 to 65 atomic %, more preferably 40 to 60 atomic %. The molybdenum content is preferably 25 to 65 atomic %, more preferably 30 to 60 atomic %. The content of tungsten is preferably 10 to 65 atomic %, more preferably 15 to 60 atomic %.

The sputtering target of the present embodiment preferably has an oxygen content of 500 ppm or less, more preferably 400 ppm or less, and still more preferably 300 ppm or less. If the oxygen content is more than 500 ppm, oxygen bonds with the added components in the target to form oxides, particles are mixed into the film when the target is used to form a thin film, or the sputtering rate varies depending on the location, resulting in Since the film thickness is uneven, the oxygen content is preferably 500 ppm or less.

The sputtering target of the present embodiment preferably has a carbon content of 200 ppm or less, more preferably 150 ppm or less, and still more preferably 100 ppm or less. If the carbon content is more than 200 ppm, the carbon bonds with the added components in the target to form carbides, particles are mixed into the film when the target is used to form a thin film, or the sputtering rate varies depending on the location, resulting in Since the film thickness is uneven, it is preferable to make carbon 200 ppm or less.

The filling rate of the sputtering target of the present embodiment is preferably 80% or more, more preferably 95% or more, and still more preferably 98% or more. By increasing the filling rate, a sputtering target with fewer voids can be produced. When the sputtering target is used for film formation, the mixing of particles can be suppressed, and the sputtering rate varies depending on the location. Therefore, it is possible to form a thin film with less variation in film thickness and composition. In the present embodiment, by setting the maximum major axis of the dispersed particles to be 500 μm or less, a sputtering target with such a high filling rate can be obtained.

The manufacturing method of the sputtering target of this embodiment is demonstrated. The manufacturing method of the sputtering target of the present embodiment includes ruthenium as the first element and any one selected from the group consisting of boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten as the first element. A method for manufacturing a 2-element alloy sputtering target, comprising: a preparation step (first step) of preparing a raw material in which the first element and the second element are in a specific element ratio; an atomization step (second step) of In a vacuum atmosphere below 1×10 ^-2 Pa, a nitrogen atmosphere containing 0-4 vol% or less hydrogen, or an inert gas atmosphere containing 0-4 vol% or less hydrogen, the above-mentioned raw materials are used by atomization. Obtaining alloy powder; and a sintering step (the third step), which is to use hot pressing (HP), spark plasma sintering (SPS) or hot isostatic pressing (HIP) to make the alloy powder in a vacuum below 50 Pa The sintered body is obtained by sintering in an atmosphere, a nitrogen atmosphere containing 0 to 4 vol% or less of hydrogen, or an inert gas atmosphere containing 0 to 4 vol% or less of hydrogen; the maximum long diameter of the alloy powder obtained by the atomization method is 500 μm or less.

[First Step (Preparation Step)] This step is a step of preparing a raw material (hereinafter also simply referred to as a "raw material") used for producing the alloy powder of the first element and the second element in the second step. The raw materials are ruthenium-boron alloy raw materials, ruthenium-aluminum alloy raw materials, ruthenium-titanium alloy raw materials, ruthenium-zirconium alloy raw materials, ruthenium-hafnium alloy raw materials, ruthenium-vanadium alloy raw materials, ruthenium-niobium alloy raw materials , ruthenium-tantalum alloy raw materials, ruthenium-chromium alloy raw materials, ruthenium-molybdenum alloy raw materials, or ruthenium-tungsten alloy raw materials. As for the raw material for producing the powder produced in the first step, the following forms can be exemplified: (1A) A form in which a single metal constituting an alloy target is prepared separately as a starting material, and mixed to form a raw material; ( 2A) Prepare an alloy whose composition is the same as that of the alloy target as the starting material, and use it as the form of the raw material; or (3A) Prepare an alloy whose constituent elements are the same as or lack a part of the alloy target and whose composition ratio deviates from the desired composition ratio , and a single metal prepared in order to adjust to a desired composition as a starting material, and these are mixed and used as a form of a raw material. As starting materials, ruthenium and boron, ruthenium and aluminum, ruthenium and titanium, ruthenium and zirconium, ruthenium and hafnium, ruthenium and vanadium, ruthenium and niobium, ruthenium and tantalum, ruthenium and chromium, ruthenium and molybdenum, or ruthenium and tungsten Any one of the groups was put into a melting device and melted to produce a raw material. In order to prevent a large amount of impurities from being mixed into the raw material after melting, it is preferable that the material of the device or container used in the melting device also use a material with less impurities. As the melting method, a method that can cope with the following melting temperature can be selected. As the melting temperature, the ruthenium-boron alloy raw material is heated at 1400-2400°C, the ruthenium-aluminum alloy raw material is heated at 1600-2400°C, and the ruthenium-titanium alloy raw material is heated at 1700-2400°C. Heating, heating the ruthenium-zirconium alloy raw material at 1700-2400 ℃, heating the ruthenium-hafnium alloy raw material at 2000-2500 ℃, heating the ruthenium-vanadium alloy raw material at 1700-2400 ℃, The ruthenium-niobium alloy raw material is heated at 1600-2400 ℃, the ruthenium-tantalum alloy raw material is heated at 1900-2800 ℃, and the ruthenium-chromium alloy raw material is heated at 1600-2400 ℃. The ruthenium-molybdenum alloy raw material is heated at ～2400°C, or the ruthenium-tungsten alloy raw material is heated at 2200～2900°C. As the atmosphere in the melting device, a vacuum atmosphere with a degree of vacuum of 1×10 ^-2 Pa or less, a nitrogen atmosphere containing 0 to 4 vol% or less of hydrogen gas, or an inert gas atmosphere containing 0 to 4 vol% or less of hydrogen gas can be used Wait.

Regarding the form of the raw material of the alloy powder, in addition to the three raw material forms described in (1A) (2A) and (3A) above, alloy grains or alloy ingots may be used, or a combination of powder, grains and ingots may be used. The powder, granules, and lumps have different particle sizes, but the particle size is not particularly limited as long as it can be used in the powder manufacturing apparatus of the second step. Specifically, since the raw material is melted in the powder manufacturing apparatus of the second step, there is no particular limitation as long as the size of the raw material can be supplied to the powder manufacturing apparatus.

[Second Step (Atomization Step)] This step is a step of producing an alloy powder of the first element and the second element. The alloy powders of the first element and the second element are ruthenium-boron alloy powder, ruthenium-aluminum alloy powder, ruthenium-titanium alloy powder, ruthenium-zirconium alloy powder, ruthenium-hafnium alloy powder, ruthenium-vanadium alloy powder Alloy powder, ruthenium-niobium alloy powder, ruthenium-tantalum alloy powder, ruthenium-chromium alloy powder, ruthenium-molybdenum alloy powder, or ruthenium-tungsten alloy powder. After the raw material produced in the first step is put into a powder production apparatus and melted to form a melt, a gas is blown into the melt to disperse the melt, and the powder is quenched and solidified to produce a powder. In order to prevent a large amount of impurities from being mixed into the alloy powder of the first element and the second element after melting, it is preferable to use the material of the device or container used in the powder manufacturing apparatus with less impurities. As the melting method, a method that can cope with the following melting temperature can be selected. As the melting temperature, the ruthenium-boron alloy raw material is heated at 1400-2400°C, the ruthenium-aluminum alloy raw material is heated at 1600-2400°C, and the ruthenium-titanium alloy raw material is heated at 1700-2400°C , heating the ruthenium-zirconium alloy raw material at 1700-2400 ℃, heating the ruthenium-hafnium alloy raw material at 2000-2500 ℃, heating the ruthenium-vanadium alloy raw material at 1700-2400 ℃, Heating ruthenium-niobium alloy raw material at 1600～2400℃, heating ruthenium-tantalum alloy raw material at 1900～2800℃, heating ruthenium-chromium alloy raw material at 1600～2400℃, heating at 1900～2800℃ The ruthenium-molybdenum alloy raw material is heated at 2400°C, or the ruthenium-tungsten alloy raw material is heated at 2200-2900°C. As the atmosphere in the powder manufacturing apparatus, a vacuum atmosphere with a degree of vacuum of 1×10 ^-2 Pa or less, a nitrogen atmosphere containing 0 to 4 vol% or less of hydrogen gas, or an inert gas atmosphere containing 0 to 4 vol% or less of hydrogen gas can be used. Wait a minute. The temperature of the molten metal at the time of blowing is preferably "the melting point of each of the alloys of the first element and the second element + 100°C or more", more preferably "depending on the first element and the second element". The type of the alloy is the respective melting point + 150 ~ 250 ℃". The reason for this is that when the temperature is too high, cooling during granulation cannot be performed sufficiently, and it becomes difficult to form powder, resulting in poor production efficiency. In addition, when the temperature is too low, the problem that nozzle clogging is likely to occur at the time of injection is likely to occur. Although nitrogen gas, argon gas, etc. are used for the gas at the time of blowing, it is not limited to this. In the case of alloy powder, the precipitation particle size of islands equivalent to sea-island structure sometimes becomes smaller. This state can be obtained at the stage of alloy powder, and this state can be maintained even after sintering or when forming a target. Therefore, by producing the alloy powder through this step, it is possible to suppress the generation of a phase containing a large amount of additives, which is produced when the sputtering target is produced by the melting method. When the film is formed after the target, the difference in sputtering rate with other parts can be suppressed. The quenched powder becomes the element ratio of the first element and the second element in the raw material prepared in the first step. In this case, the maximum major axis of the powder obtained by the atomization method is 500 μm or less, preferably 400 μm or less, and more preferably 300 μm or less. If the maximum length diameter of the powder is larger than 500 μm, the density will not be sufficient even if the sintering in the third step is carried out. When a target is used to form a thin film, particles will be mixed in and the film thickness will be uneven. Therefore, it is preferable to make the powder The maximum major diameter is 500 μm or less. Here, setting the maximum major axis to 500 μm or less means that particles with a major axis exceeding 500 μm are not included.

Preferably, the manufacturing method of the sputtering target of the present embodiment further includes, between the atomization step and the sintering step: a classification step, which removes the maximum long diameter exceeding 500 from the alloy powder obtained by the atomization method. μm particles. By adjusting the particle size by classification, a sputtering target with a higher density can be formed in the step of obtaining the sintered body. Therefore, the composition of the film obtained by forming the film using the above target material is in the in-plane direction and the film thickness direction of the film. A uniform composition distribution can be obtained.

[Step 3 (Sintering Step)] This step is a step of obtaining a sintered body to be a target from the powder obtained in the second step. As a sintering method, sintering can be performed by a hot pressing method (HP), a spark plasma sintering method (SPS), or a hot isostatic pressing method (HIP). Sintering is performed using the alloy powder of the first element and the second element obtained in the second step or the alloy powder classified by the classification step. Preferably, any one of the powders shown above is put into a mold, and the powder is sealed with a mold, a punch, etc. under a pre-pressure of 10 to 30 MPa, and then sintered. In this case, the sintering temperature is preferably 1100 to 2000° C., and the pressing pressure is preferably 40 to 196 MPa. The sintering temperature is more preferably as follows: 1150-1300°C for ruthenium-boron alloy powder, 1150-1500°C for ruthenium-aluminum alloy powder, and 1150°C for ruthenium-titanium alloy powder ～1600℃, 1150～1300℃ for ruthenium-zirconium alloy powder, 1250～1400℃ for ruthenium-hafnium alloy powder, 1250～1400℃ for ruthenium-vanadium alloy powder, if The temperature of ruthenium-niobium alloy powder is 1150～1400℃, the alloy powder of ruthenium-tantalum is 1400～1800℃, the alloy powder of ruthenium-chromium is 1100～1250℃, the alloy powder of ruthenium-molybdenum is 1100～1250℃ The temperature of the alloy powder is 1400 to 1800°C, or the temperature of the alloy powder of ruthenium-tungsten is 1500 to 2000°C. As the atmosphere in the sintering apparatus, it can be carried out in a vacuum atmosphere with a vacuum degree of 50 Pa or less, a nitrogen atmosphere containing 4 vol% or less of hydrogen, or an inert gas atmosphere containing 4 vol% or less of hydrogen. The hydrogen gas is preferably contained in an amount of 0.1 vol% or more.

By going through at least the first step to the third step, the compositional variation in the in-plane direction of the sputtering target and the thickness direction of the target can be suppressed, and a sputtering can be produced with a small content of impurities that affect the formation of a thin film. Plated target.

In the present embodiment, as the method of composition analysis under (Condition 3) or (Condition 4), there are energy dispersive X-ray spectroscopy (EDS), high frequency inductively coupled plasma emission spectrometry (ICP) or fluorescence spectroscopy. Optical X-ray analysis (XRF), etc., but preferably composition analysis based on EDS. Example

Hereinafter, although an Example is shown and this invention is demonstrated in detail, this invention is not limited to an Example, and should be interpreted.

(Example 1) The Ru raw material with a purity of 3N5up and a Nb raw material with a purity of 3N were put into the powder manufacturing apparatus, and then the inside of the powder manufacturing apparatus was adjusted to a vacuum atmosphere of 5×10 ^-3 Pa or less, and the melting temperature was 1900°C. The Ru raw material and the Nb raw material are melted to obtain a molten liquid, and then argon gas is blown into the molten liquid, and the molten liquid is scattered and quenched and solidified to prepare Ru-20 atomic % Nb powder with a maximum long diameter of 500 μm or less (in this In this case, Ru is 80 atomic % Ru, but the description of the atomic percentage of Ru is omitted, and the same applies hereinafter). Here, the Ru-20 atomic % Nb powder having a maximum major diameter of 500 μm or less was adjusted by classification. Then, the Ru-20 atomic % Nb powder was filled into a carbon mold for spark plasma sintering (hereinafter also referred to as SPS sintering). Next, the alloy powder was sealed with a die, a punch, etc. under a pre-pressurization of 30 MPa, and the die filled with the alloy powder was set in an SPS apparatus (model: SPS-825; manufactured by SPS SYNTEX). In addition, as sintering conditions, sintering was performed under the conditions of a sintering temperature of 1250° C., a pressing pressure of 55 MPa, and an atmosphere in the sintering apparatus of a vacuum atmosphere of 20 Pa or less. The Ru-20 atomic % Nb sintered body was processed using a grinding machine, a lathe, or the like to prepare a Ru-20 atomic % Nb target of Φ50.8 mm×5 mmt of Example 1.

(Comparative Example 1) In Example 1, argon gas was blown into the melt, the melt was scattered and quenched and solidified to produce Ru-20 atomic % Nb powder with a maximum major diameter of 500 μm or less. Instead of the above, argon gas was blown into the melt. A Ru-20 at % Nb sintered body was obtained in the same manner as in Example 1, except that the melt was scattered and quenched and solidified to produce Ru-20 at % Nb powder with a maximum major diameter greater than 500 μm. Here, the Ru-20 atomic % Nb powder whose maximum major diameter is larger than 500 μm is adjusted by classification. The Ru-20 at % Nb sintered body was tried to be processed using a polishing machine, but during the polishing process, a chipping occurred in the outer periphery of the plate, and the plate was cracked starting from the chipping, so that a sputtering target could not be produced.

(Comparative Example 2) Using pure Ru powder with a particle size of 100 μm or less and a purity of 3N5up, and Nb powder with a particle size of 100 μm or less and a purity of 3N5up, the amount of each powder was adjusted so as to be Ru-20 atomic % Nb, and then mixed. Then, a Ru-20 atomic % Nb sintered body was produced in the same manner as in the Example. The Ru-20 atomic % Nb sintered body after sintering was processed using a grinding machine, a lathe, etc., to prepare a Ru-20 atomic % Nb target of Φ50.8 mm×5 mmt of Comparative Example 2.

(Comparative Example 3) The Ru raw material with a purity of 3N5up and a Nb raw material with a purity of 3N were weighed so as to be Ru-20 atomic % Nb, and were melted in an arc melting apparatus (AME-300 manufactured by ULVAC) to obtain a 60 mm square × 6 The melted plate of about mm. Then I tried to machine the plate to make a sputtering target of Φ50.8 mm×5 mmt. However, during the grinding process, the outer periphery of the plate was missing, and during the cutting process of the wire discharge machining, the plate was cracked. Consequently, a sputtering target could not be produced.

(Maximum long diameter of dispersed particles under SEM observation) For the targets of Example 1, Comparative Example 1 and Comparative Example 2, an electron microscope (model JSM-6010: manufactured by JEOL Corporation) was used to measure the long diameter of the dispersed particles under direct observation in the SEM image of 1200 μm×1500 μm . The measurement results are shown in Table 1. As a result of observation, the maximum major axis of the dispersed particles in Example 1 was 250 μm, and it was confirmed that the dispersed particles were dispersed in the sputtering target. On the other hand, the maximum major axis of the dispersed particles of Comparative Example 1 was 984 μm. The maximum major diameter of the dispersed particles of Comparative Example 2 was 80 μm.

[Table 1] Maximum diameter of dispersed particles [μm] Example 1 250 Comparative Example 1 984 Comparative Example 2 80

(Concentration survey by EDS) For the targets of Example 1 and Comparative Example 2, the Nb content of S1 to S9 in FIG. 1 and the Nb content of C1 to C9 in FIG. 2 were determined by energy dispersive X-ray spectroscopy (EDS). analyze. The measurement range was set to 700 μm×900 μm. The measurement results are shown in Tables 2 to 5. According to Table 2, the average value of the Nb content of S1 to S9 in Example 1 is 19.95%, and the difference between the Nb content of S1 to S9 and the average of the Nb content of S1 to S9 is in the In Example 1, the maximum value was 0.41, and the minimum value was 0.03. According to Table 2, the average value of the Nb content of C1 to C9 in Example 1 was 20.04%, and the difference between the Nb content of C1 to C9 and the average of the Nb content of C1 to C9 was 20.04%. In Example 1, the maximum value is 0.52, and the minimum value is 0.03. For the target of Example 1, in any direction of the sputtering in-plane direction and the thickness direction of the target, the compositional deviation caused by the difference in position was small. In addition, according to Table 3, the average value of the Nb content of S1 to S9 and C1 to C9 in Example 1 is 19.99%, and the Nb content of S1 to S9 and C1 to C9 is the same as that of S1 to S9 and C1. In Example 1, the difference between the average values of the Nb content of -C9 was 0.47 at the maximum and 0.00 at the minimum. The compositional deviation of each point of the target of Example 1 is small, that is, the compositional deviation caused by the difference in position in the in-plane direction and the thickness direction of the target is small. On the other hand, according to Table 4, the average value of the Nb content of S1 to S9 in Comparative Example 2 is 20.00%, and the average of the Nb content of S1 to S9 and the average of the Nb content of S1 to S9 The difference was 0.98 at maximum and 0.25 at minimum in Comparative Example 2. According to Table 4, the average value of the Nb content of C1 to C9 in Comparative Example 2 was 20.24%, and the difference between the Nb content of C1 to C9 and the average of the Nb content of C1 to C9 was 20.24%. In Comparative Example 2, the maximum value was 1.03, and the minimum value was 0.06. In the target of Comparative Example 2, the compositional deviation due to the difference in position was small in any direction of the sputtering in-plane direction and the thickness direction of the target. In addition, according to Table 5, the average value of the Nb content of S1 to S9 and C1 to C9 in Comparative Example 2 was 20.12%, and the Nb content of S1 to S9 and C1 to C9 at each point was the same as that of S1 to S9 and C1 to C9. The difference between the average values of the Nb contents was 1.10 at the maximum and 0.18 at the minimum in Comparative Example 2. In the target of Comparative Example 2, the compositional deviation of each point is small, that is, the compositional deviation due to the difference in position in the in-plane direction and the thickness direction of the target is small.

[Table 2] In-plane direction of sputtering measuring point S1 S2 S3 S4 S5 S6 S7 S8 S9 Average of S1~S9: 19.95 measured value 19.80 19.62 20.20 20.30 20.30 19.54 19.92 20.04 19.86 Difference between S1～S9 and the average -0.15 0.33 -0.25 -0.35 -0.35 0.41 0.03 -0.09 0.09 Target thickness direction measuring point C1 C2 C3 C4 C5 C6 C7 C8 C9 Average value of C1～C9: 20.04 measured value 19.99 19.66 19.89 20.35 20.08 20.41 19.52 20.07 20.34 Difference between C1～C9 and average 0.05 0.38 0.15 -0.31 -0.04 -0.37 0.52 -0.03 -0.30 Unit: atomic percent (at.%)

[table 3] In-plane direction of sputtering Average of 18 points of S1~S9 and C1~C9: 19.99 measuring point S1 S2 S3 S4 S5 S6 S7 S8 S9 measured value 19.80 19.62 20.20 20.30 20.30 19.54 19.92 20.04 19.86 difference from average 0.19 0.37 -0.21 -0.31 -0.31 0.45 0.07 -0.05 0.13 Target thickness direction measuring point C1 C2 C3 C4 C5 C6 C7 C8 C9 measured value 19.99 19.66 19.89 20.35 20.08 20.41 19.52 20.07 20.34 difference from average 0.00 0.33 0.10 -0.36 -0.09 -0.42 0.47 -0.08 -0.35 Unit: atomic percent (at.%)

[Table 4] In-plane direction of sputtering measuring point S1 S2 S3 S4 S5 S6 S7 S8 S9 Average of S1~S9: 20.00 measured value 19.27 19.38 20.84 20.76 19.02 19.75 20.68 20.82 19.47 Difference between S1～S9 and the average 0.73 0.62 -0.84 -0.76 0.98 0.25 -0.68 -0.82 0.53 Target thickness direction measuring point C1 C2 C3 C4 C5 C6 C7 C8 C9 Average value of C1～C9: 20.24 measured value 20.44 20.38 19.58 20.82 19.85 20.59 20.99 19.21 20.30 Difference between C1～C9 and average -0.20 -0.14 0.66 -0.58 0.39 -0.35 -0.75 1.03 -0.06 Unit: atomic percent (at.%)

[table 5] In-plane direction of sputtering Average of 18 points of S1~S9 and C1~C9: 20.12 measuring point S1 S2 S3 S4 S5 S6 S7 S8 S9 measured value 19.27 19.38 20.84 20.76 19.02 19.75 20.68 20.82 19.47 difference from average 0.85 0.74 -0.72 -0.64 1.10 0.37 -0.56 -0.70 0.65 Target thickness direction measuring point C1 C2 C3 C4 C5 C6 C7 C8 C9 measured value 20.44 20.38 19.58 20.82 19.85 20.59 20.99 19.21 20.30 difference from average -0.32 -0.26 0.54 -0.70 0.27 -0.47 -0.87 0.91 -0.18 Unit: atomic percent (at.%)

(peak intensity obtained by XRD (X ray diffraction, X-ray diffraction measurement)) With respect to the targets of Example 1 and Comparative Example 2, X-ray diffraction was performed at positions S1 to S9 of (Condition 1). The relative integrated intensity of the first peak derived from the Ru-20at% Nb alloy and the relative integrated intensity of the second peak were compared with CuKα rays in the range of 2θ=20 to 90°, and the relative integrated intensity of the second peak/first peak was calculated. The ratio of the relative integrated intensities of the peaks. The calculation results are shown in Table 6. From the results in Table 6, it was confirmed that in Example 1, the ratio of the relative integrated intensity of the second peak to the relative integrated intensity of the first peak was as high as 81.8% to 84.9%. Therefore, in (Condition 1) S1 to S9 In all parts, the relative integrated intensity of the second peak is more than 60% of the relative integrated intensity of the first peak, and the sputtering target of Example 1 has a lower degree of anisotropy. Regarding the composition of the film formed by using this target, a uniform composition distribution can be obtained both in the in-plane direction of the film and in the film thickness direction. On the other hand, in Comparative Example 2, it was confirmed that the ratio of the relative integrated intensity of the second peak to the relative integrated intensity of the first peak was as low as 38.4% to 52.6%. Therefore, in (Condition 1) all of S1 to S9 The relative integrated intensity of the second peak is lower than 60% of the relative integrated intensity of the first peak. The sputtering target of Comparative Example 2 has a stronger orientation in the (101) direction and a higher degree of anisotropy. When a thin film is formed using this target material, the sputtering rate differs depending on the location, resulting in uneven film thickness.

[Table 6] Example 1 measuring point S1 S2 S3 S4 S5 S6 S7 S8 S9 2nd peak/1st peak ratio 84.6 82.9 82.3 84.3 81.8 84.9 82.2 84.2 82.6 Comparative Example 2 measuring point S1 S2 S3 S4 S5 S6 S7 S8 S9 2nd peak/1st peak ratio 39.8 45.1 47.1 52.6 48.2 41.6 38.4 41.6 47.1 unit:[%]

(oxygen and carbon content) For the targets of Example 1 and Comparative Example 2, the contents of oxygen and carbon were measured using a mass spectrometer (model: Element GD; manufactured by Thermo Fisher Scientific). The measurement results are shown in Table 7. The oxygen content of Example 1 is 43 ppm, the carbon content is 9 ppm, and the content of oxygen and carbon is small. Therefore, the oxidation and carbonization of the additive elements can be suppressed and dispersed in the sputtering target, and the composition of the film formed by using the target can be successfully obtained in both the in-plane direction and the film thickness direction of the film. Uniform composition distribution. In addition, the mixing of particles can be reduced, and the unevenness of the film thickness can be suppressed. On the other hand, in Comparative Example 2, the oxygen content was 695 ppm, the carbon content was 13 ppm, and the oxygen content was large. Therefore, if the target is heated during film formation, oxygen may bond with the additive components in the target to form oxides. Therefore, when the target is used to form a thin film, the sputtering rate varies depending on the site. different, resulting in uneven film thickness.

[Table 7] Oxygen content [ppm] Carbon content [ppm] Example 1 43 9 Comparative Example 2 695 13

(fill rate) The filling rate of the targets of Example 1, Comparative Example 1 and Comparative Example 2 was calculated using the Archimedes method. The calculation results are shown in Table 8. As a calculation method, (the measured density of the sintered body measured by the Archimedes method) was divided by the (theoretical density of the sintered body), and then multiplied by 100 to convert into a percentage, and the obtained value was used as the filling rate. The filling rate of Example 1 was 99.7%, and a sputtering target with a higher filling rate and less voids was obtained. On the other hand, the filling rate of Comparative Example 1 was 75.2%, and a sputtering target with a low filling rate and many voids was obtained. The filling rate of Comparative Example 2 was 99.9%, and a sputtering target with a higher filling rate and less voids was obtained.

[Table 8] Fill rate [%] Example 1 99.7 Comparative Example 1 75.2 Comparative Example 2 99.9

According to the results of Example 1 and Comparative Examples 1 to 3, the values of Example 1 satisfy the maximum long diameter of the dispersed particles, the composition deviation, the ratio of the relative integrated intensity of the second peak to the relative integrated intensity of the first peak, and the oxygen content. , carbon content and all of the filling rate. Therefore, the target thin film with less uneven Nb concentration was successfully formed. In addition, the contamination of particles can be suppressed, and the sputtering rate is less likely to vary depending on the site, so that a thin film with small variations in film thickness and composition can be successfully formed. Oxidation or carbonization of the additive elements can be suppressed and these can be dispersed in the sputtering target, so that when the target is used for film formation, the incorporation of particles into the film can be suppressed. In addition, regarding the composition of the film formed by using the target, a uniform composition distribution can be obtained in both the in-plane direction and the film thickness direction of the film. In addition, about the film formed by using this target, a uniform film thickness was successfully obtained. On the other hand, in Comparative Example 1, the long diameter of the dispersed particles was large, and the filling rate was low, so cracks occurred at the time of polishing, and production was not possible. In addition, in Comparative Example 2, the ratio of the relative integrated intensity of the second peak to the relative integrated intensity of the first peak was small, and the oxygen content was high, so when the sputtering target was used for film formation, the film thickness was uneven. . In Comparative Example 3, since the molten ruthenium was too hard, cracks occurred at the time of grinding or dicing, and it was not produced.

200,300,400: Sputtering targets C1~C9: Measurement positions in the thickness direction of the target D1~D9: Measurement part in the thickness direction of the target J: length K: perimeter L: virtual crosshair L1: Longitudinal L2: horizontal length O: center, center of gravity P1~P9: Measurement positions in the in-plane direction of sputtering Q: Virtual crosshair r: radius S1~S9: Measurement positions in the in-plane direction of sputtering X: Center

FIG. 1 is a schematic view showing the measurement site of the disk-shaped target in the sputtering in-plane direction. FIG. 2 is a schematic view showing the measurement site of the disk-shaped target shown in the cross section B-B in the target thickness direction. FIG. 3 is a schematic view showing a measurement site of a square plate-shaped target in the sputtering in-plane direction. FIG. 4 is a schematic view showing the measurement site of the square plate-shaped target shown in the C-C cross section in the target thickness direction. FIG. 5 is a conceptual diagram for explaining the measurement site of the cylindrical target.

200: Sputtering target

L: virtual crosshair

O: Center

r: radius

S1~S9: Measurement positions in the in-plane direction of sputtering

Claims (11)

A sputtering target, which is an alloy containing ruthenium as the first element and any one selected from boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten as the second element The sputtering target is characterized in that: The sputtering target has dispersed particles including two phases, the two phases include an intermetallic compound phase, and the intermetallic compound phase includes two elements of the first element and the second element; The maximum major diameter of the dispersed particles is 500 μm or less. The sputtering target according to claim 1, wherein the two phases are (1) a combination of the above-mentioned intermetallic compound phase and the metal phase of the first element, that is, a metal ruthenium phase, (2) a combination of two of the above-mentioned intermetallic compound phases, Or (3) a combination of the above-mentioned intermetallic compound phase and the above-mentioned metal phase of the second element. A sputtering target, which is an alloy containing ruthenium as the first element and any one selected from boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten as the second element The sputtering target is characterized in that: The sputtering target has dispersed particles including an intermetallic compound phase, and the intermetallic compound phase includes two elements of the first element and the second element; The maximum long diameter of the above-mentioned dispersed particles is 500 μm or less, Under (Condition 1) or (Condition 2), there is at least one location which is the relative integrated intensity of the second peak obtained by X-ray diffraction of the sputtering target in the sputtering in-plane direction is more than 60% of the relative integrated intensity of the first peak, (Condition 1) In-plane direction of sputtering: The sputtering target is a disk-shaped target with a center O and a radius r, and the measurement site is set to a total of 9 sites, that is, a virtual cross orthogonal to the center O as an intersection On the line, 1 site at the center O, a total of 4 sites with a distance of 0.45r from the center O, and a total of 4 sites with a distance of 0.9r from the center O; (Condition 2) In-plane direction of sputtering: the above-mentioned sputtering target is a rectangle with a vertical length L1 and a horizontal length L2 (including a square with equal L1 and L2; or a rectangle including a cylindrical side with a length J and a perimeter K developed The rectangle formed later, in this form, L2 corresponds to length J, L1 corresponds to perimeter K, and between length J and perimeter K, the relationship of J>K, J=K or J<K is established), and The measurement site is set to a total of 9 sites, that is, when the virtual cross line orthogonal to the center of gravity O is perpendicular to the side of the rectangle, one site of the center of gravity O, the center of gravity O is in the vertical direction of the virtual cross line A total of 2 locations with a distance of 0.25L1 from the center of gravity O, a total of 2 locations with a distance of 0.25L2 from the center of gravity O in the horizontal direction, a total of 2 locations with a distance of 0.45L1 from the center of gravity O in the vertical direction, and a distance from the center of gravity O in the horizontal direction by 0.45L2 2 parts in total. The sputtering target of claim 3, wherein under (Condition 1) or (Condition 2), there are 40% or more of the following portion, which is the sputtering target in the sputtering in-plane direction by X The relative integrated intensity of the second peak obtained by ray diffraction is more than 60% of the relative integrated intensity of the first peak. The sputtering target according to claim 3 or 4, wherein the difference between the composition of the above-mentioned sputtering target under (Condition 3) or (Condition 4) in the sputtering in-plane direction and in the thickness direction of the target and the reference composition is within Within ±1.5%, the above reference composition is the average value of the composition of a total of 18 parts measured according to (Condition 3) or (Condition 4), (Condition 3) In-plane direction of sputtering: The sputtering target is a disk-shaped target with a center O and a radius r, and the measurement site is set to a total of 9 sites, that is, a virtual cross orthogonal to the center O as an intersection On the line, 1 site at the center O, a total of 4 sites with a distance of 0.45r from the center O, and a total of 4 sites with a distance of 0.9r from the center O; The thickness direction of the target material: form a cross-section passing through any line in the virtual cross line, and the cross-section is a rectangle with a vertical t (that is, the thickness of the target is t) and a horizontal 2r, and for the measurement site, the following 9 sites in total are set. It is the measurement point, that is, the center X on the vertical intersecting line passing through the center O and the total of 3 points (called a point, X point, and b point) that are 0.45t away from the center X in the upper and lower sides. A total of 2 parts with a left and right side spacing of 0.9r, a total of 2 parts from the X point to the left and right side spacing of 0.9r, and a total of 2 parts from the b point to the left and right side spacing of 0.9r; (Condition 4) In-plane direction of sputtering: the above-mentioned sputtering target is a rectangle with a vertical length L1 and a horizontal length L2 (including a square with equal L1 and L2; or a rectangle including a cylindrical side with a length J and a perimeter K developed The rectangle formed later, in this form, L2 corresponds to length J, L1 corresponds to perimeter K, and between length J and perimeter K, the relationship of J>K, J=K or J<K is established), and The measurement site is set to a total of 9 sites, that is, when a virtual cross line orthogonal to the center of gravity O is perpendicular to the sides of the rectangle, one site of the center of gravity O, on the virtual cross line, and the center of gravity O are in the longitudinal direction. A total of 2 locations with a distance of 0.25L1, a total of 2 locations with a distance of 0.25L2 from the center of gravity O in the horizontal direction, a total of 2 locations with a distance of 0.45L1 from the center of gravity O in the vertical direction, and a distance from the center of gravity O in the horizontal direction by 0.45L2 2 parts in total; The thickness direction of the target material: form a cross-section through a line parallel to any one of the vertical L1 and the horizontal L2 in the virtual cross line. When one side is the horizontal L2, the cross-section is the vertical t (that is, the thickness of the above-mentioned target material is t ), a rectangle of horizontal L2, and for the measurement site, a total of 9 sites are set as the measurement site, that is, a total of 3 sites ( Referred to as point a, point X, point b), on the above-mentioned cross-section from point a toward the left and right sides with a distance of 0.45L2 in total, 2 points in total with a distance of 0.45L2 from the X point to the left and right sides, and from b The location is oriented to a total of 2 parts with a distance of 0.45L2 between the left and right sides. The sputtering target according to claim 4 or 5, wherein the crystallite size of the first peak is below 400 Å. The sputtering target according to any one of claims 1 to 6, wherein the content of the second element is 3 to 70 atomic %. The sputtering target according to any one of claims 1 to 7, wherein the oxygen content is below 500 ppm. The sputtering target according to any one of claims 1 to 8, wherein the carbon content is below 200 ppm. A method for producing a sputtering target, comprising ruthenium as the first element and any one selected from boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten as the second element A method for producing an alloy sputtering target of elements, characterized by comprising: a preparation step of preparing a raw material in which the first element and the second element are in a specific element ratio; an atomization step of 1×10 ^-2 In a vacuum atmosphere below Pa, a nitrogen atmosphere containing 0-4 vol% or less hydrogen, or an inert gas atmosphere containing 0-4 vol% or less hydrogen, the above-mentioned raw materials are used to obtain alloy powder by atomization; and sintering step , which uses the hot pressing method, spark plasma sintering method (SPS) or hot isostatic pressing sintering method (HIP), in a vacuum atmosphere below 50 Pa, a nitrogen atmosphere containing 0-4 vol% or less of hydrogen, or a 0- The sintered body is obtained by sintering the above-mentioned alloy powder in an inert gas atmosphere of hydrogen of 4 vol% or less; the maximum long diameter of the alloy powder obtained by the above-mentioned atomization method is 500 μm or less. The method for manufacturing a sputtering target according to claim 10, further comprising: between the atomizing step and the sintering step: The classification step is to remove particles with a maximum major diameter exceeding 500 μm from the above-mentioned alloy powder obtained by the above-mentioned atomization method.

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