Sputtering target and method of manufacturing the same

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 μm.

Description

[Technical Field]

[0001] The present disclosure relates to a sputtering target suitable for forming a protective film of a mask blank, which serves as an original for a mask used in performing extreme ultraviolet (EUV) lithography using EUV light, or a pellicle film for preventing foreign matter from adhering to a mask pattern surface. [Background technology]

[0002] In semiconductor devices, there is a demand for miniaturization of the electronic circuits that make up the IC chips of electronic components, and technologies such as EUV lithography are being used to form fine circuit patterns. However, defects such as minute dust particles or scratches on the order of a few nanometers that occur during manufacturing can become fatal defects in operation, so the material of the thin film used in the mask blanks, which are the original plates for the masks, is also important.

[0003] For EUV blanks or thin films called pellicles, alloy materials containing ruthenium are used because of their superiority in transmitting or absorbing EUV light and in thermal conductivity, and the thin films are formed using sputtering.

[0004] A sputtering target used in producing a reflective mask blank for EUV lithography is disclosed, which is made of a ruthenium compound containing ruthenium and at least one element selected from niobium, molybdenum, zirconium, titanium, lanthanum, silicon, boron, and yttrium (see, for example, Patent Document 1). Patent Document 1 states that the contents of niobium, molybdenum, zirconium, titanium, lanthanum, and silicon in the compound are preferably in the range of 3 to 75 atomic %, and particularly from the viewpoint of improving chemical resistance, a range of 40 to 75 atomic % is desirable. Patent Document 1 also states that the contents of boron and yttrium in the compound are preferably in the range of 3 to 50 atomic %, because these metals are easily oxidized and high contents of these metals may form an oxide layer on the surface of the formed ruthenium compound film, resulting in degradation of optical properties (e.g., reflectance of EUV light). Furthermore, Patent Document 1 states that among impurities, the oxygen content is 2000 ppm or less, and the carbon content is 200 ppm or less, and that the low oxygen and carbon contents reduce particles generated from the target during film formation.

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-283054 Summary of the Invention [Problem to be solved by the invention]

[0006] However, if particles that cause film defects are generated during film formation, they will adhere to the film, causing defects and reducing film yield. Since blanks are patterned on top of them to form the blueprints for semiconductors, particle adhesion to the film is an extremely serious issue. Pellicles also have a reduced ability to transmit EUV light in areas where particles adhere, which affects the transfer of circuits and reduces yield. There are many factors that cause particles to be generated during film formation, but particles originating from the target include arcing from voids due to poor density or arcing from oxides on the target surface.

[0007] In addition, in the case of blanks or pellicles, the thickness of the film formed is extremely thin and the area of ​​the formed film is relatively wide, so the in-plane uniformity of the film thickness and the in-plane uniformity of the composition are important. Therefore, in the past, it has been necessary to improve the density of the target and reduce the amount of oxygen in sputtering targets. However, with the formation of fine circuit patterns in recent years, the particles that cause defects have become even smaller, and it has become suspected that not only the particle sources mentioned above but also the materials added to ruthenium themselves are scattering during film formation.

[0008] To reduce oxygen content or improve density, sputtering targets have been manufactured using the melting method. However, ruthenium and its additive elements are generally high-melting materials with melting points exceeding 1600°C, making them difficult to melt. Furthermore, ruthenium and additive elements form various intermetallic compounds (IMCs), which are prone to cracking during the solidification process and can cause cracks during processing after melting and solidification, making target fabrication difficult. Even if the target material can be fabricated, the IMCs precipitate and coarsen during solidification, degrading the compositional distribution in the target's in-plane and cross-sectional directions (also known as the target thickness direction). This results in varying sputtering rates within the target and poor uniformity in the in-plane composition and thickness distribution of the deposited film. While hot-working targets is commonly used to refine the structure, hot-working is not feasible due to the precipitation and coarsening of IMCs, which can lead to cracking or fracture.

[0009] Sintering is one method for highly dispersing additive elements in the target. The finer the additive element powder, the easier it is to disperse it in the target. However, handling very fine powders is difficult because highly reactive additive elements can cause fires. Furthermore, even for stable additive elements, the finer the powder, the larger the specific surface area, making oxidation more likely to occur, resulting in a high oxygen content in the target. Therefore, relatively coarse-grained powders must be used, but achieving high dispersion requires high-energy mixing processes. However, preventing oxidation of the additive elements requires extensive atmospheric control and can lead to contamination from the mixing medium, making this method unsuitable for EUV sputtering targets, which require high purity.

[0010] Therefore, an object of the present disclosure is to provide a sputtering target and a method for manufacturing the same that can obtain a uniform composition distribution in the in-plane direction and thickness direction of the film formed. [Means for solving the problem]

[0011] As a result of intensive research to solve the above problems, the present inventors have found that by setting the major axis of dispersed particles in a sputtering target to a predetermined particle diameter, it is possible to obtain a uniform composition distribution in the in-plane direction of the film and in the thickness direction of the film with respect to the composition of the deposited film, and have completed the present invention. That is, the sputtering target according to the present invention is a sputtering target containing ruthenium as a first element and boron, aluminum, titanium, zirconium, or the like as a second element. M, B Nasium, Nio B,K ROM and Molybdenum N and any one selected from the group consisting of: a sputtering target of an alloy composed of the first element and the second element, the sputtering target having dispersed particles composed of two phases including an intermetallic compound phase composed of two elements, the first element and the second element, the maximum major axis of the dispersed particles being 500 μm or less. By setting the particle diameter to a predetermined value, the dispersed particles can be highly dispersed in the sputtering target, and therefore, the composition of the film formed using the target can have a uniform composition distribution in the in-plane direction and the thickness direction of the film.

[0012] In the sputtering target according to the present invention, the two phases include (1) a combination of the intermetallic compound phase and a metallic ruthenium phase, which is a metallic phase of the first element, (2) a combination of two types of the intermetallic compound phases, or (3) a combination of the intermetallic compound phase and a metallic phase of the second element.

[0013] The sputtering target according to the present invention is a sputtering target of an alloy composed of ruthenium as a first element and any one selected from boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten as a second element. The sputtering target has dispersed particles containing an intermetallic compound phase composed of two elements, the first element and the second element, and the maximum major axis of the dispersed particles is 500 μm or less. In (Condition 1) or (Condition 2), there is at least one location where the relative integrated intensity of the second peak by X-ray diffraction in the in-plane direction of the sputtering surface of the sputtering target is 60% or more with respect to the relative integrated intensity of the first peak. The composition of the sputtering target in the sputtering in-plane direction and the target thickness direction under (Condition 3) or (Condition 4) is within ±1.5% of a reference composition, and the reference composition is an average value of compositions measured at a total of 18 locations according to (Condition 3) or (Condition 4), and the crystallite size of the first peak is 400 Å or less. It is characterized by this. (Condition 1) In-plane direction of the sputtering surface: The sputtering target is a disc-shaped target with a center O and a radius r. The measurement locations are on a virtual crosshair that intersects at the center O and is orthogonal. The total number of measurement locations is 9, including 1 location at the center O, 4 locations each at a distance of 0.45r from the center O, and 4 locations each at a distance of 0.9r from the center O. (Condition 2) In-plane direction of the sputtering surface: The sputtering target is a rectangle with a vertical length of L1 and a horizontal length of L2 (including a square where L1 and L2 are equal. Or the rectangle includes a rectangle obtained by unfolding the side surface of a cylindrical shape with a length J and a perimeter K. In this form, L2 corresponds to the length J, L1 corresponds to the perimeter K, and the relationship between the length J and the perimeter K is J>K, J=K or J<K). The measurement locations are on a virtual crosshair that intersects at the center of gravity O and is orthogonal. When the virtual crosshair is orthogonal to the sides of the rectangle, the total number of measurement locations is 9, including 1 location at the center of gravity O, 2 locations each on the virtual crosshair at a distance of 0.25L1 from the center of gravity O in the vertical direction, 2 locations each on the virtual crosshair at a distance of 0.25L2 from the center of gravity O in the horizontal direction, 2 locations each on the virtual crosshair at a distance of 0.45L1 from the center of gravity O in the vertical direction, and 2 locations each on the virtual crosshair at a distance of 0.45L2 from the center of gravity O in the horizontal direction. By reducing the difference between the relative integrated intensity of the second peak and the relative integrated intensity of the first peak and lowering the degree of anisotropy of the structure, it is possible to suppress differences in sputtering rate during film formation and obtain a uniform film thickness. The composition of the sputtering target in the sputtering in-plane direction and the target thickness direction under (Condition 3) or (Condition 4) is within ±1.5% of a reference composition, and the reference composition is the average value of the compositions measured at a total of 18 locations according to (Condition 3) or (Condition 4). By suppressing deviations in the target composition, it is possible to suppress differences in the sputtering rate during film formation and to suppress deviations in the composition and film thickness of the film after film formation. In addition, it is possible to suppress the inclusion of particles caused by microprotrusions due to differences in the sputtering rate. (Condition 3) Sputtering in-plane direction: The sputtering target is a disk-shaped target with a center O and a radius r, and the measurement locations are nine locations in total, on imaginary cross lines that intersect at right angles with the center O as the intersection point: one location at the center O, four locations at 0.45r from the center O, and four locations at 0.9r from the center O. Target thickness direction: A cross section passing through one of the imaginary cross lines is formed, and the cross section is a rectangle with a length of t (i.e., the thickness of the target is t) and a width of 2r. The measurement points are the center X on the vertical transverse line passing through the center O, and three points (referred to as points a, X, and b) that are 0.45t above and below the center X, two points on the cross section that are 0.9r away from point a towards the left and right sides, two points that are 0.9r away from point X towards the left and right sides, and two points that are 0.9r away from point b towards the left and right sides, for a total of nine measurement points. (Condition 4) In-plane direction of the sputtering target: The sputtering target is a rectangle with a vertical length of L1 and a horizontal length of L2 (including a square where L1 and L2 are equal. Alternatively, the rectangle includes a rectangle formed by unfolding the side surface of a cylinder with a length J and a perimeter K. In this form, L2 corresponds to the length J, L1 corresponds to the perimeter K, and the relationship between the length J and the perimeter K is J > K, J = K, or J < K). And the measurement points are virtual crosshairs that intersect at the center of gravity O and are perpendicular to each other. When the virtual crosshairs are perpendicular to the sides of the rectangle, there is one point at the center of gravity O, a total of two points on the virtual crosshairs that are 0.25L1 away from the center of gravity O in the vertical direction, a total of two points that are 0.25L2 away from the center of gravity O in the horizontal direction, a total of two points that are 0.45L1 away from the center of gravity O in the vertical direction, and a total of two points that are 0.45L2 away from the center of gravity O in the horizontal direction, for a total of nine points. Target thickness direction: Among the virtual crosshairs, a cross-section is formed by a line parallel to one of the sides of vertical L1 and horizontal L2. When one side is horizontal L2, the cross-section is a rectangle with a vertical length of t (i.e., the thickness of the target is t) and a horizontal length of L2. And the measurement points are the center X on the vertical cross-section passing through the center of gravity O and a total of three points (referred to as point a, point X, and point b) that are 0.45t away from the center X vertically up and down, a total of two points on the cross-section that are 0.45L2 away from point a towards the left and right side edges, a total of two points that are 0.45L2 away from point X towards the left and right side edges, and a total of two points that are 0.45L2 away from point b towards the left and right side edges, for a total of nine points as the measurement locations.

[0014] In the sputtering target according to the present invention, it is preferable that, in (Condition 1) or (Condition 2), there are 40% or more regions where the relative integrated intensity of the second peak in the in-plane direction of the sputtering target is 60% or more of the relative integrated intensity of the first peak. The presence of many regions where the difference between the relative integrated intensity of the second peak and the relative integrated intensity of the first peak is small reduces the degree of anisotropy of the structure, thereby suppressing differences in sputtering rate during film formation and achieving a uniform film thickness.

[0015] The sputtering target according to the present invention is an alloy sputtering target comprising ruthenium as a first element and any one selected from boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten as a second element, the sputtering target having dispersed particles containing an intermetallic compound phase consisting of two elements, the first element and the second element, the dispersed particles having a maximum major axis of 500 μm or less, (Condition 1) or (Condition 2), there is at least one location where the relative integrated intensity of the second peak measured by X-ray diffraction in the in-plane direction of the sputtering target is 60% or more of the relative integrated intensity of the first peak, (Condition 1) or (Condition 2), there is 40% or more locations where the relative integrated intensity of the second peak measured by X-ray diffraction in the in-plane direction of the sputtering target is 60% or more of the relative integrated intensity of the first peak, and the crystallite size of the first peak is 400 Å or less.

[0016] In the sputtering target according to the present invention, the crystallite size of the first peak is preferably 400 .ANG. or less. By reducing the crystallite size, a homogeneous thin film can be formed.

[0017] In the sputtering target according to the present invention, the content of the second element is preferably 3 to 70 atomic %, which improves the corrosion resistance of the composition of the deposited film and ensures a reflectivity that satisfies the EUV requirement.

[0018] In the sputtering target according to the present invention, the oxygen content is preferably 500 ppm or less. By suppressing the formation of an oxide of the second element in the sputtering target due to oxygen bonding with the second element, abnormal discharge due to the oxide of the second element can be suppressed, thereby suppressing the generation of particles.

[0019] In the sputtering target according to the present invention, the carbon content is preferably 200 ppm or less. By suppressing the formation of carbides of the second element in the sputtering target due to carbon bonding with the second element, abnormal discharge due to the carbides of the second element can be suppressed, thereby suppressing the generation of particles.

[0020] The method for producing a sputtering target according to the present invention includes the steps of: preparing a raw material in which the first element and the second element have a predetermined element ratio; -2 The method includes an atomization step of atomizing the raw materials to obtain an alloy powder in a vacuum atmosphere of 50 Pa or less, a nitrogen gas 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, and a sintering step of sintering the alloy powder by hot pressing (HP), spark plasma sintering (SPS), or hot isostatic pressing (HIP) in a vacuum atmosphere of 50 Pa or less, a nitrogen gas 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 to obtain a sintered body, wherein the alloy powder obtained by the atomization method has a maximum major axis of 500 μm or less. Since the additive elements can be dispersed in the sputtering target while suppressing oxidation or carbonization, the composition of the film formed using the target can be uniformly distributed in both the in-plane direction and the thickness direction of the film while suppressing particle contamination.

[0021] The method for producing a sputtering target according to the present invention preferably further comprises, between the atomizing step and the sintering step, a classification step for removing particles having a maximum major axis exceeding 500 μm from the alloy powder obtained by the atomizing method. In the step of obtaining a sintered body, a high-density sputtering target can be formed, and therefore, a film formed using the target can have a uniform composition distribution in both the in-plane direction and the thickness direction of the film. [Effects of the Invention]

[0022] The present disclosure can provide a sputtering target and a method for manufacturing the same that can obtain a uniform composition distribution in the in-plane direction and thickness direction of the film formed. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 2 is a schematic diagram showing measurement points in the in-plane direction of the disk-shaped target for sputtering. [Figure 2] FIG. 1 is a schematic diagram showing measurement points in the target thickness direction of a disk-shaped target shown in the B-B cross section. [Figure 3] FIG. 1 is a schematic diagram showing measurement points in the in-plane direction of a square plate-shaped target for sputtering. [Figure 4] FIG. 1 is a schematic diagram showing measurement points in the target thickness direction of a square plate-shaped target shown in the CC cross section. [Figure 5] FIG. 1 is a conceptual diagram for explaining measurement points on a cylindrical target. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, the present invention will be described in detail with reference to the embodiments, but the present invention is not limited to these descriptions. Various modifications may be made to the embodiments as long as the effects of the present invention are achieved.

[0025] The sputtering target according to this embodiment is an alloy sputtering target comprising ruthenium as a first element and any one selected from boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten as a second element. The sputtering target has dispersed particles composed of two phases including an intermetallic compound phase composed of the first element and the second element, and the maximum major axis of the dispersed particles is 500 μm or less. For example, when the sputtering target is a sintered body, the dispersed particles present in the sputtering target correspond to the constituent particles of the sintered body. The dispersed particles have a plurality of crystal grains.

[0026] The maximum major axis of the dispersed particles is 500 μm or less, preferably 250 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less. If the maximum major axis of the dispersed particles is greater than 500 μm, the dispersed particles will be unevenly distributed within the sputtering target, resulting in compositional variations depending on the location on the sputtering target. When a film is formed using a sputtering target with compositional variations, compositional variations will occur in the in-plane direction and thickness direction of the film. Therefore, it is preferable to set the maximum major axis of the dispersed particles to 500 μm or less. Setting the maximum major axis to 500 μm or less means that no particles with a major axis exceeding 500 μm are included. The maximum major axis is determined by measuring the distance from one end of the largest dispersed particle to the other end of an SEM image within a 1200 μm x 1500 μm area based on the image scale.

[0027] In the sputtering target according to this embodiment, the two-phase structure includes (1) a combination of an intermetallic compound phase and a metallic ruthenium phase, which is a metallic phase of a first element; (2) a combination of two types of intermetallic compound phases; or (3) a combination of an intermetallic compound phase and a metallic phase of a second element. In this embodiment, the number of phases is determined by the phases identified by X-ray diffraction. Intermetallic compounds formed at grain boundaries are not included in the two-phase structure. The dispersed particles have two types of crystal grains corresponding to the two-phase structure.

[0028] The grain boundary includes the boundary between a dispersed particle and a dispersed particle adjacent to the dispersed particle, and the boundary between a crystal grain and a crystal grain adjacent to the crystal grain.

[0029] Using the example of three types of intermetallic compounds, Ru2AE, RuAE, and RuAE2, we will explain the following: "The two phases are (1) a combination of an intermetallic compound phase and a metallic ruthenium phase, which is the metal phase of the first element," "The two phases are (2) a combination of two types of intermetallic compound phases," and "The two phases are (3) a combination of an intermetallic compound phase and a metal phase of the second element." In this case, the phase forms that appear include a metallic ruthenium phase only (including a solid solution in which the second element is solid-dissolved in ruthenium), a combination of a Ru phase (including a solid solution in which the second element is solid-dissolved in ruthenium) with one of the Ru2AE phase, RuAE phase, and RuAE2 phase, a combination of the Ru2AE phase and RuAE phase, a combination of the Ru2AE phase and RuAE2 phase, a combination of the RuAE phase only, a combination of the RuAE phase and RuAE2 phase, a combination of the RuAE2 phase and RuAE2 phase, a combination of the RuAE2 phase, RuAE phase, and Ru2AE phase with an AE phase (including a solid solution in which ruthenium is solid-dissolved in the second element), and a metallic phase of the second element only (including a solid solution in which ruthenium is solid-dissolved in the second element). Among these, "the two phases are (1) a combination of an intermetallic compound phase and a metallic ruthenium phase, which is a metal phase of the first element" refers to a combination of the Ru phase and any one of the Ru2AE phase, RuAE phase, and RuAE2 phase. Also, "the two phases are (2) a combination of two types of intermetallic compound phases" refers to a combination of the Ru2AE phase and the RuAE phase, the Ru2AE phase and the RuAE2 phase, or the RuAE phase and the RuAE2 phase. Furthermore, "the two phases are (3) a combination of the intermetallic compound phase and the metal phase of the second element" refers to a combination of the AE phase and any one of the RuAE2 phase, RuAE phase, and Ru2AE phase. Cases in which there are two or four or more types of intermetallic compounds can be classified in a similar manner.

[0030] The two phases appear due to the presence of two types of crystal grains with different compositions in the dispersed particles. An example will be explained using three types of intermetallic compounds: Ru2AE, RuAE, and RuAE2. When "the two phases are (1) a combination of an intermetallic compound phase and a metallic ruthenium phase, which is the metallic phase of the first element," the dispersed particles contain crystal grains of the Ru phase and crystal grains of one of the Ru2AE, RuAE, and RuAE2 phases. Furthermore, "the two phases are (2) a combination of two types of intermetallic compound phases" refers to a form in which crystal grains of the Ru2AE phase and crystal grains of the RuAE phase exist in the dispersed particles, a form in which crystal grains of the Ru2AE phase and crystal grains of the RuAE2 phase exist in the dispersed particles, or a form in which crystal grains of the RuAE phase and crystal grains of the RuAE2 phase exist in the dispersed particles. Furthermore, "the two phases are a combination of (3) an intermetallic compound phase and a metal phase of the second element" means that crystal grains of one of the RuAE2 phase, RuAE phase, and Ru2AE phase and crystal grains of the AE phase are present in the dispersed particles. Cases in which there are two or four or more types of intermetallic compounds can also be classified according to the same concept.

[0031] The sputtering target according to this embodiment is an alloy sputtering target comprising ruthenium as a first element and any one selected from boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten as a second element, the sputtering target having dispersed particles containing an intermetallic compound phase consisting of the first and second elements, the maximum major axis of the dispersed particles being 500 μm or less, and (Condition 1) or (Condition 2), at least one location exists where the relative integrated intensity of a second peak in an in-plane direction of the sputtering target is 60% or more of the relative integrated intensity of the first peak. The first peak is the highest peak among peaks derived from an alloy of the first and second elements that appear in the CuKα, 2θ = 20 to 90° region in an X-ray diffraction spectrum. The second peak is the second highest peak among the peaks resulting from an alloy of the first element and the second element that appear in the CuKα, 2θ=20 to 90° region in the X-ray diffraction spectrum. (Condition 1) In the in-plane direction of sputtering: the sputtering target is a disk-shaped target with a center O and a radius r, and the measurement points are on a virtual crosshair that intersects at the center O and is orthogonal, including a total of 9 points: one point at the center O, a total of 4 points at a distance of 0.45r from the center O, and a total of 4 points at a distance of 0.9r from the center O. (Condition 2) In the in-plane direction of sputtering: the sputtering target is a rectangle with a vertical length of L1 and a horizontal length of L2 (where a square with L1 equal to L2 is included. Alternatively, the rectangle includes a rectangle obtained by unfolding the side surface of a cylindrical shape with a length J and a perimeter K. In this form, L2 corresponds to the length J, L1 corresponds to the perimeter K, and the relationship between the length J and the perimeter K is J>K, J=K, or J<K.), and the measurement points are on a virtual crosshair that intersects at the center of gravity O and is orthogonal. When the virtual crosshair is orthogonal to the sides of the rectangle, a total of 9 points include one point at the center of gravity O, a total of 2 points on the virtual crosshair at a distance of 0.25L1 from the center of gravity O in the vertical direction, a total of 2 points on the virtual crosshair at a distance of 0.25L2 from the center of gravity O in the horizontal direction, a total of 2 points on the virtual crosshair at a distance of 0.45L1 from the center of gravity O in the vertical direction, and a total of 2 points on the virtual crosshair at a distance of 0.45L2 from the center of gravity O in the horizontal direction.

[0032] In X-ray diffraction, in (Condition 1) or (Condition 2), it is preferable that the measurement ranges of the 9 points are each 10 mm × 10 mm. The determination that the relative integrated intensity of the second peak by X-ray diffraction in the in-plane direction of the sputtering target is 60% or more with respect to the relative integrated intensity of the first peak is to select the first peak and the second peak based on the graph obtained by X-ray diffraction, calculate the relative integrated intensity of the first peak and the relative integrated intensity of the second peak using waveform analysis software for X-ray diffraction, and determine whether the relative integrated intensity of the second peak is 60% or more with respect to the relative integrated intensity of the first peak.

[0033] The relative integrated intensity of the second peak in the in-plane direction of the sputtering target by X-ray diffraction is 60% or more, preferably 65% ​​or more, and more preferably 70% or more of the relative integrated intensity of the first peak. In (Condition 1) or (Condition 2), if the relative integrated intensity of the second peak in X-ray diffraction is less than 60% of the relative integrated intensity of the first peak, variations in the thickness of the deposited film will occur, so it is preferable that the relative integrated intensity of the second peak in X-ray diffraction is 60% or more of the relative integrated intensity of the first peak.

[0034] In the sputtering target according to this embodiment, under (Condition 1) or (Condition 2), it is preferable that 40% or more, and more preferably 50% or more, of the locations are present where the relative integrated intensity of the second peak by X-ray diffraction in the sputtering in-plane direction of the sputtering target is 60% or more of the relative integrated intensity of the first peak. The presence of many regions where the difference between the relative integrated intensity of the second peak and the relative integrated intensity of the first peak is small reduces the degree of anisotropy of the structure, thereby suppressing differences in sputtering rate during film formation and achieving a uniform film thickness. Under (Condition 1) or (Condition 2), "40% or more of the locations are present where the relative integrated intensity of the second peak by X-ray diffraction in the sputtering in-plane direction of the sputtering target is 60% or more of the relative integrated intensity of the first peak" means that, out of nine measurement locations under (Condition 1) or (Condition 2), "40% or more of the locations are present where the relative integrated intensity of the second peak by X-ray diffraction in the sputtering in-plane direction of the sputtering target is 60% or more of the relative integrated intensity of the first peak" and "50% or more of the locations are present where the relative integrated intensity of the second peak by X-ray diffraction in the sputtering in-plane direction of the sputtering target is 60% or more of the relative integrated intensity of the first peak" are present. If there are four or more "areas where the relative integrated intensity of the second peak due to X-ray diffraction in the sputtering in-plane direction of the sputtering target is 60% or more of the relative integrated intensity of the first peak" out of nine locations, then "40% or more of the locations where the relative integrated intensity of the second peak due to X-ray diffraction in the sputtering in-plane direction of the sputtering target is 60% or more of the relative integrated intensity of the first peak" is satisfied.

[0035] In the sputtering target according to this embodiment, the composition of the sputtering target in the sputtering in-plane direction and the target thickness direction under (Condition 3) or (Condition 4) is preferably within ±1.5% of a reference composition, and the reference composition is preferably the average value of the compositions measured at a total of 18 locations according to (Condition 3) or (Condition 4). (Condition 3) Sputtering in-plane direction: The sputtering target is a disk-shaped target with a center O and a radius r, and the measurement locations are nine locations in total, on imaginary cross lines that intersect at right angles with the center O as the intersection point: one location at the center O, four locations at 0.45r from the center O, and four locations at 0.9r from the center O. Target thickness direction: A cross section passing through one of the imaginary cross lines is formed, and the cross section is a rectangle with a length of t (i.e., the thickness of the target is t) and a width of 2r. The measurement points are the center X on the vertical transverse line passing through the center O, and three points (referred to as points a, X, and b) that are 0.45t above and below the center X, two points on the cross section that are 0.9r away from point a towards the left and right sides, two points that are 0.9r away from point X towards the left and right sides, and two points that are 0.9r away from point b towards the left and right sides, for a total of nine measurement points. (Condition 4) Sputtering in-plane direction: The sputtering target is a rectangle with a vertical length of L1 and a horizontal length of L2 (including a square where L1 and L2 are equal. Alternatively, the rectangle includes a rectangle formed by unfolding the side surface of a cylinder with a length J and a perimeter K. In this form, L2 corresponds to the length J, L1 corresponds to the perimeter K, and the relationship between the length J and the perimeter K is J > K, J = K, or J < K). And the measurement points are virtual crosshairs that intersect at the center of gravity O and are perpendicular to each other. When the virtual crosshairs are perpendicular to the sides of the rectangle, there is one point at the center of gravity O, a total of two points on the virtual crosshairs that are at a distance of 0.25L1 from the center of gravity O in the vertical direction, a total of two points that are at a distance of 0.25L2 from the center of gravity O in the horizontal direction, a total of two points that are at a distance of 0.45L1 from the center of gravity O in the vertical direction, and a total of two points that are at a distance of 0.45L2 from the center of gravity O in the horizontal direction, for a total of nine points. Target thickness direction: Among the virtual crosshairs, a cross-section is formed by a line parallel to either one of the sides of length L1 (vertical) and length L2 (horizontal). When one side is horizontal L2, the cross-section is a rectangle with a vertical length of t (i.e., the thickness of the target is t) and a horizontal length of L2. And the measurement points are the center X on the vertical cross-section passing through the center of gravity O and a total of three points (referred to as point a, point X, and point b) that are 0.45t away from the center X above and below, a total of two points on the cross-section that are 0.45L2 away from point a towards the left and right side edges, a total of two points that are 0.45L2 away from point X towards the left and right side edges, and a total of two points that are 0.45L2 away from point b towards the left and right side edges, for a total of nine points as the measurement locations.

[0036] In the sputtering target according to this embodiment, the composition of the sputtering target in the sputtering in-plane direction and the target thickness direction under (Condition 3) or (Condition 4) preferably differs from a reference composition by within ±1.5%, more preferably within ±1.25%, and even more preferably within ±1%. The reference composition is the average value of the composition measured at a total of 18 locations according to (Condition 3) or (Condition 4). If the difference from the reference composition is greater than ±1.5%, the composition will vary significantly depending on the location on the sputtering target. Therefore, if a film is formed using a sputtering target with such compositional deviation, compositional deviation will also occur in the in-plane direction and thickness direction of the film. Therefore, it is preferable that the composition of the sputtering target in the sputtering in-plane direction and the target thickness direction differ from the reference composition by within ±1.5%.

[0037] In the composition, in (Condition 3) or (Condition 4), it is preferable that each of the nine measurement ranges is 700 μm×900 μm.

[0038] FIG. 1 is a schematic diagram showing measurement points (hereinafter, simply referred to as measurement points) in the in-plane direction of the sputtering disk-shaped target. The measurement points in the in-plane direction of the sputtering targets under (Condition 1) and (Condition 3) will be described with reference to FIG. 1. In the case of a disk-shaped target, the radius is preferably 25 to 225 mm, and more preferably 50 to 200 mm. The thickness of the target is preferably 3 to 30 mm, and more preferably 5 to 26 mm. This embodiment is expected to be more effective for large targets.

[0039] 1, sputtering target 200 is a disk-shaped target with a center O and a radius r. Measurement locations are nine locations on imaginary cross lines (L) that intersect at right angles with the center O as the intersection point: one location (S1) at the center O, four locations (S3, S5, S6, and S8) spaced 0.45r from the center O, and four locations (S2, S4, S7, and S9) spaced 0.9r from the center O.

[0040] FIG. 2 is a schematic diagram showing measurement points in the target thickness direction of a disk-shaped target shown in the B-B cross section of FIG. 1. The measurement points in the target thickness direction of the sputtering target under (Condition 3) will be explained with reference to FIG. 2.

[0041] In Figure 2, the BB cross section in Figure 1 is a rectangle with a length of t (i.e., the thickness of the target is t) and a width of 2r. The measurement points are the center X (C1) on a vertical cross line passing through the center O shown in Figure 1, three points (referred to as point a (C4), point X (C1), and point b (C5)) that are 0.45t above and below the center X, two points (C6, C7) that are 0.9r above and below the center X on the cross section, two points (C2, C3) that are 0.9r above and below the center X on the left and right sides, and two points (C8, C9) that are 0.9r above and below the center X on the left and right sides.

[0042] FIG. 3 is a schematic diagram showing measurement points in the in-plane direction of the sputtering of a square plate-shaped target. Measurement points in the in-plane direction of the sputtering of the sputtering targets under (Condition 2) and (Condition 4) will be described with reference to FIG. 3. In the case of a rectangular or square target, the vertical and horizontal lengths are preferably 50 to 450 mm, and more preferably 100 to 400 mm. The thickness of the target is preferably 3 to 30 mm, and more preferably 5 to 26 mm. This embodiment is expected to be more effective for large targets.

[0043] Sputtering target 300 is a rectangular target with a vertical length of L1 and a horizontal length of L2 (however, this also includes a square where L1 and L2 are equal), and Figure 3 shows a configuration of sputtering target 300 where L1 = L2. The measurement locations are virtual crosshairs (Q) that intersect at right angles with the center of gravity O as the intersection point, and when the virtual crosshairs are perpendicular to the sides of the rectangle (or square), there is one measurement location (P1) at the center of gravity O, two measurement locations (P6, P8) on the virtual crosshairs that are 0.25L1 vertically from the center of gravity O, two measurement locations (P3, P5) that are 0.25L2 horizontally from the center of gravity O, two measurement locations (P7, P9) that are 0.45L1 vertically from the center of gravity O, and two measurement locations (P2, P4) that are 0.45L2 horizontally from the center of gravity O, for a total of nine measurement locations. When the sputtering target is rectangular, L1 and L2 can be selected appropriately regardless of the length of the sides.

[0044] FIG. 4 is a schematic diagram showing measurement points in the target thickness direction of a square plate-shaped target shown in the CC cross section of FIG. 3. Referring to FIG. 4, the measurement points in the target thickness direction of the sputtering target (Condition 4) will be explained.

[0045] In Figure 4, the CC cross section in Figure 3 forms a cross section passing through a line parallel to the horizontal side, and the cross section is a rectangle with a length of t (i.e., the thickness of the target is t) and a width of L2. The measurement points are the center X on a vertical transverse line passing through the center of gravity O, three points in total (referred to as point a (D4), point X (D1), and point b (D5)) that are 0.45t above and below the center X, two points (D6, D7) on the cross section that are 0.45L2 away from point a towards the left and right sides, two points (D2, D3) that are 0.45L2 away from point X towards the left and right sides, and two points (D8, D9) that are 0.45L2 away from point b towards the left and right sides, for a total of nine measurement points.

[0046] (Cylindrical sputtering target) FIG. 5 is a conceptual diagram for explaining measurement positions of a cylindrical target. When the sputtering target has a cylindrical shape, the side surface of the cylinder is the sputtering surface, and since the developed view is a rectangle (including a square), (Condition 2) or (Condition 4) can be considered in the same way as in FIGS. 3 and 4. The rectangle includes a rectangle obtained by developing the side surface of a cylinder with a length J and a circumference K. In this form, L2 corresponds to the length J, L1 corresponds to the circumference K, and the relationship of J > K, J = K, or J < K holds between the length J and the circumference K. In FIG. 5, when the sputtering target 400 has a cylindrical shape with a height (length) J and a body circumference K, consider the E-E cross-section and the D-D developed surface with the cross-section at both ends. First, the measurement positions in the target thickness direction are considered in the same way as in FIG. 4 in the E-E cross-section. That is, assuming 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, these are taken as the measurement positions. Also, the measurement positions in the sputtering surface inner direction are considered in the same way as in FIG. 3 in the D-D developed surface. That is, assuming that the height J of the cylindrical material corresponds to L2 in FIG. 3 and the body circumference K of the cylindrical material corresponds to L1 in FIG. 3, these are taken as the measurement positions. In the case of a cylindrical target, the length of the body circumference of the cylinder is preferably 100 to 350 mm, more preferably 150 to 300 mm. The length of the cylinder is preferably 300 to 3000 mm, more preferably 500 to 2000 mm. The thickness of the target is preferably 3 to 30 mm, more preferably 5 to 26 mm. In this embodiment, more effects can be expected for large targets.

[0047] For the sputtering target according to this embodiment, the crystallite size of the first peak is preferably 400 Å or less, more preferably 350 Å or less, and even more preferably 300 Å or less. When the crystallite size of the first peak is larger than 400 Å, bias occurs in the orientation of the crystallites, resulting in differences in sputtering rate and film thickness depending on the location. Therefore, it is preferable to make the crystallite size of the first peak 400 Å or less. The method for measuring the crystallite size is to measure the crystallite size using waveform analysis software for X-ray diffraction.

[0048] In the sputtering target according to this embodiment, the content of the second element is preferably 3 to 70 atomic %, more preferably 5 to 65 atomic %, and even more preferably 10 to 60 atomic %. If the content is less than 3 atomic %, improvement in the reflectance of the film formed using the target cannot be expected, and if the content is more than 70 atomic %, the chemical resistance is reduced due to the small amount of ruthenium, making it difficult to use the film formed using the target. Therefore, the content is preferably 3 to 70 atomic %.

[0049] The boron content is preferably 25 to 65 atomic %, and more preferably 30 to 60 atomic %. The aluminum content is preferably 20 to 60 atomic %, and more preferably 30 to 55 atomic %. The titanium content is preferably 10 to 65 atomic %, and more preferably 25 to 50 atomic %. The zirconium content is preferably 15 to 65 atomic %, and more preferably 20 to 50 atomic %. The hafnium content is preferably 15 to 65 atomic %, and more preferably 20 to 50 atomic %. The vanadium content is preferably 35 to 65 atomic %, and more preferably 40 to 60 atomic %. The niobium content is preferably 15 to 60 atomic %, and more preferably 20 to 50 atomic %. The tantalum content is preferably 10 to 65 atomic %, and more preferably 25 to 40 atomic %. The chromium content 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 tungsten content is preferably 10 to 65 atomic %, more preferably 15 to 60 atomic %.

[0050] The sputtering target according to this embodiment preferably has an oxygen content of 500 ppm or less, more preferably 400 ppm or less, and even more preferably 300 ppm or less. If the oxygen content is more than 500 ppm, the additive components in the target will combine with oxygen to form oxides, and when a thin film is formed using the target, particles will be mixed into the film, or the sputtering rate will vary depending on the location, resulting in uneven film thickness. Therefore, it is preferable to keep the oxygen content at 500 ppm or less.

[0051] The sputtering target according to this embodiment preferably has a carbon content of 200 ppm or less, more preferably 150 ppm or less, and even more preferably 100 ppm or less. If the carbon content is more than 200 ppm, the additive components in the target will bond with the carbon to form carbides, and when a thin film is formed using the target, particles will be mixed into the film, and the sputtering rate will vary from place to place, resulting in uneven film thickness. Therefore, it is preferable to keep the carbon content at 200 ppm or less.

[0052] The filling rate of the sputtering target according to this embodiment is preferably 80% or more, more preferably 95% or more, and even more preferably 98% or more. By increasing the filling rate, a sputtering target with fewer voids can be obtained. When a film is formed using this sputtering target, particle contamination can be suppressed, and the sputtering rate is less likely to vary from location to location, resulting in a thin film with less variation in film thickness and composition. In this embodiment, a sputtering target with such a high filling rate can be obtained by setting the maximum major axis of the dispersed particles to 500 μm or less.

[0053] The method for manufacturing a sputtering target according to this embodiment will be described. The method for manufacturing a sputtering target according to this embodiment is a method for manufacturing a sputtering target of an alloy composed of ruthenium as a first element and any one selected from boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten as a second element, and includes a preparation step (first step) of preparing a raw material in which the first element and the second element are in a predetermined element ratio; -2 The method includes an atomization step (second step) in which the raw materials are used to obtain alloy powder by atomization in a vacuum atmosphere of 50 Pa or less, a nitrogen gas 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, and a sintering step (third step) in which the alloy powder is sintered using hot pressing (HP), spark plasma sintering (SPS), or hot isostatic pressing (HIP) in a vacuum atmosphere of 50 Pa or less, a nitrogen gas 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, to obtain a sintered body, and the maximum major axis of the alloy powder obtained by the atomization method is 500 μm or less.

[0054] [1st process (preparation process)] This step is a step of preparing the raw material (hereinafter simply referred to as "raw material") used in producing the alloy powder of the first element and the second element in step 2. The raw material is a raw material for a ruthenium-boron alloy, a raw material for a ruthenium-aluminum alloy, a raw material for a ruthenium-titanium alloy, a raw material for a ruthenium-zirconium alloy, a raw material for a ruthenium-hafnium alloy, a raw material for a ruthenium-vanadium alloy, a raw material for a ruthenium-niobium alloy, a raw material for a ruthenium-tantalum alloy, a raw material for a ruthenium-chromium alloy, a raw material for a ruthenium-molybdenum alloy, or a raw material for a ruthenium-tungsten alloy. The raw materials for producing the powder produced in the first step can be exemplified by (1A) preparing the individual metals constituting the alloy target as starting raw materials and mixing them to form the raw material, (2A) preparing an alloy with the same composition as the alloy target as the starting raw material, or (3A) preparing an alloy with the same or partially missing constituent elements as the alloy target, whose composition ratio deviates from the desired composition ratio, and mixing them to form the raw material. The starting raw materials are 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, which are introduced into a melting apparatus and melted to produce the raw material. It is preferable to use materials with low impurity content for the melting apparatus and containers to prevent large amounts of impurities from being mixed into the raw material after melting. The dissolution method to be selected is one that can handle the following dissolution temperatures.The melting temperatures are 1400 to 2400°C for ruthenium-boron alloy raw materials, 1600 to 2400°C for ruthenium-aluminum alloy raw materials, 1700 to 2400°C for ruthenium-titanium alloy raw materials, 1700 to 2400°C for ruthenium-zirconium alloy raw materials, 2000 to 2500°C for ruthenium-hafnium alloy raw materials, and 1700 to 2400°C for ruthenium-zirconium alloy raw materials. The raw materials for the ruthenium-vanadium alloy, the raw materials for the ruthenium-niobium alloy at 1600-2400°C, the raw materials for the ruthenium-tantalum alloy at 1900-2800°C, the raw materials for the ruthenium-chromium alloy at 1600-2400°C, the raw materials for the ruthenium-molybdenum alloy at 1900-2400°C, or the raw materials for the ruthenium-tungsten alloy at 2200-2900°C are heated. The atmosphere inside the melting equipment has a vacuum degree of 1x10. ‐2 The atmosphere may be a vacuum atmosphere of 0 Pa or less, a nitrogen gas 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.

[0055] The form of the alloy powder raw material may be any of the three raw material forms described above in (1A), (2A), and (3A), or it may be alloy grains or alloy ingots, or a combination of powder, grains, and ingots. Powder, grains, and ingots represent different particle sizes, but there are no particular restrictions on the particle size as long as they can be used in the powder manufacturing equipment in the second step. Specifically, since the raw materials are melted in the powder manufacturing equipment in the second step, there are no particular restrictions on the size of the raw materials as long as they can be fed into the powder manufacturing equipment.

[0056] [Second process (atomization process)] This step produces an alloy powder of a first element and a second element. The alloy powder of a first element and a second element may be ruthenium-boron alloy powder, ruthenium-aluminum alloy powder, ruthenium-titanium alloy powder, ruthenium-zirconium alloy powder, ruthenium-hafnium alloy powder, ruthenium-vanadium alloy powder, ruthenium-niobium alloy powder, ruthenium-tantalum alloy powder, ruthenium-chromium alloy powder, ruthenium-molybdenum alloy powder, or ruthenium-tungsten alloy powder. The raw materials produced in the first step are loaded into a powder production device and melted to form a molten metal. Gas is then blown into the molten metal, causing it to scatter and rapidly solidify, producing a powder. It is preferable to use materials with low impurities for the equipment and containers used in the powder production device to prevent large amounts of impurities from being mixed into the alloy powder of the first element and the second element after melting. The melting method is selected to be compatible with the following melting temperatures: The melting temperatures are 1400 to 2400°C for ruthenium-boron alloy raw materials, 1600 to 2400°C for ruthenium-aluminum alloy raw materials, 1700 to 2400°C for ruthenium-titanium alloy raw materials, 1700 to 2400°C for ruthenium-zirconium alloy raw materials, 2000 to 2500°C for ruthenium-hafnium alloy raw materials, and 1700 to 2400°C for ruthenium-zirconium alloy raw materials. The raw materials for the ruthenium-vanadium alloy, the raw materials for the ruthenium-niobium alloy at 1600-2400°C, the raw materials for the ruthenium-tantalum alloy at 1900-2800°C, the raw materials for the ruthenium-chromium alloy at 1600-2400°C, the raw materials for the ruthenium-molybdenum alloy at 1900-2400°C, or the raw materials for the ruthenium-tungsten alloy at 2200-2900°C are heated. The atmosphere in the powder manufacturing equipment has a vacuum degree of 1x10 ‐2The spraying is carried out in a vacuum atmosphere of 100 Pa or less, a nitrogen gas 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. The temperature of the molten metal when spraying is preferably "at least 100°C above the melting point of the alloy of the first and second elements, depending on the type of alloy." It is more preferable to spray at "at least 150 to 250°C above the melting point of the alloy of the first and second elements, depending on the type of alloy." If the temperature is too high, cooling during granulation is insufficient, making it difficult to obtain powder and resulting in poor production efficiency. On the other hand, if the temperature is too low, problems such as nozzle clogging during spraying are likely to occur. Gases used when spraying include, but are not limited to, nitrogen and argon. In the case of alloy powder, the precipitated particle size corresponding to the islands in the sea-island structure may be small. This state is already achieved in the alloy powder stage and is maintained even after sintering or when the target is formed. Therefore, by producing the alloy powder through this process, the generation of a phase containing a large amount of additives, which occurs when producing a sputtering target by a melting method, can be suppressed. When a sputtering target is produced using the alloy powder produced through this process and a film is formed, the difference in sputtering rate from other locations can be suppressed. The quenched powder has the element ratio of the first element to the second element in the raw material prepared in the first process. 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 major axis of the powder is greater than 500 μm, the density will be insufficient even after sintering in the third process, and when a thin film is formed using the target, particles will be mixed in, resulting in uneven film thickness. Therefore, it is preferable that the maximum major axis of the powder be 500 μm or less. Here, the maximum major axis being 500 μm or less means that no particles having a major axis exceeding 500 μm are included.

[0057] The method for producing a sputtering target according to this embodiment preferably further includes a classification step between the atomization step and the sintering step, in which particles having a maximum major axis exceeding 500 μm are removed from the alloy powder obtained by the atomization method. By adjusting the particle size by classification, a sputtering target with higher density can be formed in the step of obtaining a sintered body, and therefore, the composition of the film formed using the target can have a uniform composition distribution in the in-plane direction of the film and in the thickness direction.

[0058] [Third process (sintering process)] This step is a step of obtaining a sintered body as a target from the powder obtained in the second step. Sintering is performed by hot pressing (HP), spark plasma sintering (SPS), or hot isostatic pressing (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 in the classification step. It is preferable to pack any of the powders listed above into a mold, seal the powder with a mold and punch, etc., under a preliminary pressure of 10 to 30 MPa, and then sinter. In this case, the sintering temperature is preferably 1100 to 2000°C, and the pressure is preferably 40 to 196 MPa. The sintering temperature is 1150 to 1300°C for ruthenium-boron alloy powder, 1150 to 1500°C for ruthenium-aluminum alloy powder, 1150 to 1600°C for ruthenium-titanium alloy powder, 1150 to 1300°C for ruthenium-zirconium alloy powder, 1250 to 1400°C for ruthenium-hafnium alloy powder, and 1250 to 1400°C for ruthenium-vanadium alloy powder. For ruthenium-niobium alloy powder, the temperature is 1250 to 1400°C, for ruthenium-tantalum alloy powder, 1400 to 1800°C, for ruthenium-chromium alloy powder, 1100 to 1250°C, for ruthenium-molybdenum alloy powder, or 1400 to 1800°C, more preferably 1500 to 2000°C, for ruthenium-tungsten alloy powder. The atmosphere inside the sintering apparatus is a vacuum atmosphere with a degree of vacuum of 50 Pa or less, a nitrogen gas atmosphere containing 4 vol% or less of hydrogen gas, or an inert gas atmosphere containing 4 vol% or less of hydrogen gas. Preferably, the hydrogen gas content is 0.1 vol% or more.

[0059] By going through at least steps 1 to 3, it is possible to suppress compositional deviations in the in-plane direction of the sputtering target and in the thickness direction of the target, and to produce a sputtering target with a low content of impurities that affect thin film formation.

[0060] In this embodiment, the composition analysis method in (Condition 3) or (Condition 4) may be energy dispersive X-ray spectroscopy (EDS), inductively coupled plasma optical emission spectroscopy (ICP), or X-ray fluorescence spectroscopy (XRF), but composition analysis by EDS is preferred. [Example]

[0061] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0062] Example 1 Ru raw material with a purity of 3N5up and Nb raw material with a purity of 3N were put into the powder manufacturing equipment, and then the inside of the powder manufacturing equipment was heated to 5 × 10 -3 A vacuum atmosphere of less than 100 Pa was created, and the Ru and Nb raw materials were melted at a melting temperature of 1900°C to produce a molten alloy. Argon gas was then blown into the molten alloy, causing it to scatter and rapidly solidify. This produced Ru-20 at.% Nb powder (in this case, the Ru content was 80 at.% Ru, but the atomic percentage of Ru is omitted; the same applies hereinafter) with a maximum diameter of less than 500 μm. The Ru-20 at.% Nb powder with a maximum diameter of less than 500 μm was prepared by classification. The Ru-20 at.% Nb powder was then packed into a carbon mold for spark plasma sintering (SPS sintering). The alloy powder was then sealed using a mold and punch under a pre-pressure of 30 MPa, and the mold filled with the alloy powder was placed in an SPS apparatus (model number: SPS-825, manufactured by SPS Syntex Co., Ltd.). The sintering was carried out under the following conditions: sintering temperature: 1250°C, pressure: 55 MPa, and the atmosphere in the sintering apparatus was a vacuum atmosphere of 20 Pa or less. The Ru-20 atomic % Nb sintered body was processed using a grinding machine, a lathe, etc. to produce a Ru-20 atomic % Nb target of Example 1 with a diameter of 50.8 mm and thickness of 5 mm.

[0063] (Comparative Example 1) A Ru-20 at.% Nb sintered body was obtained in the same manner as in Example 1, except that instead of producing Ru-20 at.% Nb powder with a maximum diameter of 500 μm or less by spraying argon gas onto the molten metal, splashing the molten metal, and rapidly solidifying it, argon gas was sprayed onto the molten metal, splashing the molten metal, and rapidly solidifying it, producing Ru-20 at.% Nb powder with a maximum diameter of greater than 500 μm. Here, the Ru-20 at.% Nb powder with a maximum diameter of greater than 500 μm was prepared by classification. An attempt was made to process the Ru-20 at.% Nb sintered body using a grinding machine, but chips occurred on the outer periphery of the plate during grinding, and cracks developed in the plate from the chips, making it impossible to produce a sputtering target.

[0064] (Comparative Example 2) 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 were mixed together, adjusting the amounts of each powder to obtain Ru-20 atomic % Nb. Then, a Ru-20 atomic % Nb sintered body was produced in the same manner as in the examples. The sintered Ru-20 atomic % Nb sintered body was processed using a grinding machine, lathe, etc. to produce a Ru-20 atomic % Nb target of Comparative Example 2 with a diameter of 50.8 mm and a thickness of 5 mm.

[0065] (Comparative Example 3) Ru raw material with a purity of 3N5up and Nb raw material with a purity of 3N were weighed out to give Ru-20 atomic % Nb, and melted in an arc melting apparatus (ULVAC AME-300 model) to obtain a melted plate approximately 60 mm square x 6 mm. Next, we attempted to machine this plate to produce a sputtering target with a diameter of 50.8 mm x 5 mm thickness, but grinding caused chipping on the outer periphery of the plate, and cutting by wire electrical discharge machining caused cracks in the plate, making it impossible to produce a sputtering target.

[0066] (Maximum diameter of dispersed particles observed by SEM) For the targets of Example 1, Comparative Example 1, and Comparative Example 2, the major axis of the dispersed particles was measured by direct observation in a 1200 μm × 1500 μm SEM image using an electron microscope (model number JSM-6010: manufactured by JEOL Corporation). The measurement results are shown in Table 1. As a result of the observation, the maximum major axis of the dispersed particles of Example 1 was 250 μm, confirming 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 axis of the dispersed particles of Comparative Example 2 was 80 μm.

[0067] [Table 1]

[0068] (Content survey by EDS) For the targets of Example 1 and Comparative Example 2, compositional analysis was performed by energy dispersive X-ray spectroscopy (EDS) to measure the Nb content of S1 to S9 in FIG. 1 and the Nb content of C1 to C9 in FIG. 2. The measurement range was 700 μm × 900 μm. The measurement results are shown in Tables 2 to 5. As shown in Table 2, the average Nb content of S1 to S9 in Example 1 was 19.95%, and the difference between the Nb content of each point of S1 to S9 and the average Nb content of S1 to S9 in Example 1 was a maximum of 0.41 and a minimum of 0.03. As shown in Table 2, the average Nb content of C1 to C9 in Example 1 was 20.04%, and the difference between the Nb content of each point of C1 to C9 and the average Nb content of C1 to C9 in Example 1 was a maximum of 0.52 and a minimum of 0.03. The target of Example 1 had small variations in composition due to differences in location both in the in-plane direction of sputtering and in the thickness direction of the target. Furthermore, as shown in Table 3, the average value of the Nb content of S1 to S9 and C1 to C9 in Example 1 was 19.99%, and the difference between the Nb content of each point of S1 to S9 and C1 to C9 and the average value of the Nb content of S1 to S9 and C1 to C9 in Example 1 was a maximum of 0.47 and a minimum of 0.00. The target of Example 1 had small variations in composition at each point, i.e., the variations in composition due to differences in location both in the in-plane direction and the thickness direction of the target were small. On the other hand, as seen in Table 4, the average Nb content of S1 to S9 in Comparative Example 2 was 20.00%, and the difference between the Nb content of each point of S1 to S9 and the average Nb content of S1 to S9 was a maximum of 0.98 and a minimum of 0.25 in Comparative Example 2. As seen in Table 4, the average Nb content of C1 to C9 in Comparative Example 2 was 20.24%, and the difference between the Nb content of each point of C1 to C9 and the average Nb content of C1 to C9 was a maximum of 1.03 and a minimum of 0.06 in Comparative Example 2. The target of Comparative Example 2 showed small deviations in composition due to location in both the sputtering in-plane direction and the target thickness direction. Furthermore, from 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 difference between the Nb content of each point of S1 to S9 and C1 to C9 and the average value of the Nb content of S1 to S9 and C1 to C9 in Comparative Example 2 was a maximum of 1.10 and a minimum of 0.18.The target of Comparative Example 2 had small deviations in composition at each point, that is, small deviations in composition due to differences in location in the in-plane direction and thickness direction of the target.

[0069] [Table 2]

[0070] [Table 3]

[0071] [Table 4]

[0072] [Table 5]

[0073] (Peak intensity by XRD) X-ray diffraction was performed on the targets of Example 1 and Comparative Example 2 at positions S1 to S9 under Condition 1. The relative integrated intensities of the first and second peaks derived from the Ru-20 atomic % Nb alloy were compared over the CuKα, 2θ range of 20 to 90°, to calculate the ratio of the relative integrated intensity of the second peak to the relative integrated intensity of the first peak. The calculation results are shown in Table 6. From the results in Table 6, in Example 1, the ratio of the relative integrated intensity of the second peak to the relative integrated intensity of the first peak was high at 81.8% to 84.9%, and therefore the relative integrated intensity of the second peak was 60% or more of the relative integrated intensity of the first peak at all positions S1 to S9 under Condition 1, confirming that the sputtering target of Example 1 has a low degree of anisotropy. The film deposited using this target had a uniform composition distribution in both the in-plane and thickness directions of the film. On the other hand, 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 low at 38.4% to 52.6%, and therefore the relative integrated intensity of the second peak was lower than 60% of the relative integrated intensity of the first peak at all points S1 to S9 of (Condition 1), confirming that the sputtering target of Comparative Example 2 had a strong orientation in the (101) direction and a high degree of anisotropy.When a thin film was formed using this target, the sputtering rate varied depending on the location, resulting in uneven film thickness.

[0074] [Table 6]

[0075] (oxygen and carbon content) The oxygen and carbon contents of the targets of Example 1 and Comparative Example 2 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 was 43 ppm, and the carbon content was 9 ppm, indicating low oxygen and carbon contents. Therefore, the additive elements could be dispersed in the sputtering target while suppressing oxidation and carbonization, and the film formed using this target had a uniform composition distribution in the in-plane and thickness directions of the film. Furthermore, particle contamination was reduced, and film thickness variation was suppressed. On the other hand, the oxygen content of Comparative Example 2 was 695 ppm, and the carbon content was 13 ppm, indicating a high oxygen content. Therefore, when the target was heated during film formation, the additive elements in the target combined with oxygen to form oxides. This resulted in different sputtering rates and film thickness variations when a thin film was formed using the target.

[0076] [Table 7]

[0077] (Filling rate) The packing ratios of the targets of Example 1, Comparative Example 1, and Comparative Example 2 were calculated using the Archimedes method. The calculation results are shown in Table 8. The calculation method was to divide (the actual density of the sintered body measured by the Archimedes method) by (the theoretical density of the sintered body), and then multiply this by 100 to convert to a percentage, to obtain the packing ratio. The packing ratio of Example 1 was 99.7%, and a sputtering target with a high packing ratio and few voids was obtained. In contrast, the packing ratio of Comparative Example 1 was 75.2%, and a sputtering target with a low packing ratio and many voids was obtained. The packing ratio of Comparative Example 2 was 99.9%, and a sputtering target with a high packing ratio and few voids was obtained.

[0078] [Table 8]

[0079] From the results of Example 1 and Comparative Examples 1 to 3, in Example 1, the maximum major axis of the dispersed particles, the compositional deviation, the ratio of the relative integrated intensity of the second peak to the relative integrated intensity of the first peak, the oxygen content, the carbon content, and the packing ratio were all satisfactory. Therefore, a thin film with a small variation in the target Nb concentration could be formed. Furthermore, particle contamination could be suppressed, and the sputtering rate was less likely to vary from location to location, allowing for the formation of a thin film with little variation in film thickness or composition. Since the additive elements could be dispersed in the sputtering target while suppressing oxidation and carbonization, particle contamination into the film could be suppressed when forming a film using this target. Furthermore, the composition of the film formed using this target was able to achieve a uniform composition distribution in both the in-plane direction and the thickness direction of the film. Furthermore, the film formed using this target was able to achieve a uniform film thickness. On the other hand, in Comparative Example 1, the major axis of the dispersed particles was large and the packing ratio was low, so cracks occurred during the grinding process and the film could not be formed. 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 a film was formed using the sputtering target, the film thickness varied. In Comparative Example 3, the dissolved ruthenium was too hard, so cracks occurred during grinding and cutting, making it impossible to produce a film. [Explanation of symbols]

[0080] 200,300,400 sputtering targets O center, center of gravity L,Q virtual crosshairs S1 to S9 Measurement points in the sputtering plane C1~C9 Measurement points in the target thickness direction P1~P9 Measurement points in the sputtering in-plane direction D1~D9 Measurement points in the target thickness direction

Claims

1. A sputtering target of an alloy comprising ruthenium as a first element and any one selected from boron, aluminum, titanium, zirconium, vanadium, niobium, chromium, and molybdenum as a second element, the sputtering target has dispersed particles composed of two phases including an intermetallic compound phase composed of two elements, the first element and the second element, A sputtering target characterized in that the dispersed particles have a maximum major axis of 500 μm or less.

2. 2. The sputtering target according to claim 1, wherein the two phases are (1) a combination of the intermetallic compound phase and a metallic ruthenium phase that is a metallic phase of the first element, (2) a combination of two types of the intermetallic compound phases, or (3) a combination of the intermetallic compound phase and a metallic phase of the second element.

3. A sputtering target of an alloy comprising ruthenium as a first element and any one selected from boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten as a second element, the sputtering target has dispersed particles containing an intermetallic compound phase consisting of two elements, the first element and the second element, The maximum major axis of the dispersed particles is 500 μm or less, In (Condition 1) or (Condition 2), there is at least one location where the relative integrated intensity of the second peak in the in-plane direction of the sputtering target by X-ray diffraction is 60% or more of the relative integrated intensity of the first peak, The composition of the sputtering target in the in-plane direction and the thickness direction of the target under (Condition 3) or (Condition 4) is within ±1.5% of a reference composition, and the reference composition is an average value of the compositions measured at a total of 18 locations under (Condition 3) or (Condition 4), A sputtering target characterized in that the crystallite size of the first peak is 400 Å or less. (Condition 1) Sputtering in-plane direction: The sputtering target is a disk-shaped target with a center O and a radius r, and the measurement locations are nine locations in total, on virtual cross lines that intersect at right angles with the center O as the intersection point, including one location at the center O, four locations at a distance of 0.45r from the center O, and four locations at a distance of 0.9r from the center O. (Condition 2) Sputtering in-plane direction: The sputtering target is a rectangle with a vertical length of L1 and a horizontal length of L2 (however, this includes a square where L1 and L2 are equal. Alternatively, the rectangle includes a rectangle formed by unfolding the side of a cylinder with length J and perimeter K, and in this form, L2 corresponds to the length J, L1 corresponds to the perimeter K, and the length J and the perimeter K have the relationship J>K, J=K, or J<K), and the measurement locations are virtual cross lines that intersect at right angles with the center of gravity O as the intersection point, and when the virtual cross lines are perpendicular to the sides of the rectangle, there are a total of nine measurement locations: one location at the center of gravity O, two locations on the virtual cross lines that are 0.25L1 vertically from the center of gravity O, two locations that are 0.25L2 horizontally from the center of gravity O, two locations that are 0.45L1 vertically from the center of gravity O, and two locations that are 0.45L2 horizontally from the center of gravity O. (Condition 3) Sputtering in-plane direction: The sputtering target is a disk-shaped target with a center O and a radius r, and the measurement locations are nine locations in total, on virtual cross lines that intersect at right angles with the center O as the intersection point, including one location at the center O, four locations at a distance of 0.45r from the center O, and four locations at a distance of 0.9r from the center O. Target thickness direction: A cross section passing through one of the imaginary cross lines is formed, and the cross section is a rectangle with a length of t (i.e., the thickness of the target is t) and a width of 2r. The measurement points are the center X on a vertical transverse line passing through the center O, three points in total (referred to as points a, X, and b) that are 0.45t above and below the center X, two points on the cross section that are 0.9r away from point a towards the left and right sides, two points in total that are 0.9r away from point X towards the left and right sides, and two points in total that are 0.9r away from point b towards the left and right sides, for a total of nine measurement points. (Condition 4) Sputtering in-plane direction: The sputtering target is a rectangle with a vertical length of L1 and a horizontal length of L2 (however, this includes a square where L1 and L2 are equal. Alternatively, the rectangle includes a rectangle formed by unfolding the side of a cylinder with length J and perimeter K, and in this form, L2 corresponds to the length J, L1 corresponds to the perimeter K, and the length J and the perimeter K have the relationship J>K, J=K, or J<K), and the measurement locations are virtual cross lines that intersect at right angles with the center of gravity O as the intersection point, and when the virtual cross lines are perpendicular to the sides of the rectangle, there are a total of nine measurement locations: one location at the center of gravity O, two locations on the virtual cross lines that are 0.25L1 vertically from the center of gravity O, two locations that are 0.25L2 horizontally from the center of gravity O, two locations that are 0.45L1 vertically from the center of gravity O, and two locations that are 0.45L2 horizontally from the center of gravity O. Target thickness direction: A cross section is formed that passes through a line parallel to either the vertical side L1 or the horizontal side L2 of the imaginary cross line, and when one side is horizontal L2, the cross section is a rectangle with a vertical length of t (i.e., the thickness of the target is t) and a horizontal length of L2, and the measurement points are the center X on a vertical transverse line that passes through the center of gravity O, three points in total (referred to as point a, point X, and point b) that are 0.45t above and below the center X, two points on the cross section that are 0.45L2 away from point a towards the left and right sides, two points in total that are 0.45L2 away from point X towards the left and right sides, and two points in total that are 0.45L2 away from point b towards the left and right sides, for a total of nine measurement points.

4. The sputtering target according to claim 3, characterized in that, in (Condition 1) or (Condition 2), there are 40% or more locations where the relative integrated intensity of the second peak by X-ray diffraction in the sputtering in-plane direction of the sputtering target is 60% or more of the relative integrated intensity of the first peak.

5. A sputtering target of an alloy comprising ruthenium as a first element and any one selected from boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten as a second element, the sputtering target has dispersed particles containing an intermetallic compound phase consisting of two elements, the first element and the second element, The maximum major axis of the dispersed particles is 500 μm or less, In (Condition 1) or (Condition 2), there is at least one location where the relative integrated intensity of the second peak in the in-plane direction of the sputtering target by X-ray diffraction is 60% or more of the relative integrated intensity of the first peak, In (Condition 1) or (Condition 2), there are 40% or more portions where the relative integrated intensity of the second peak by X-ray diffraction in the sputtering in-plane direction of the sputtering target is 60% or more of the relative integrated intensity of the first peak, A sputtering target characterized in that the crystallite size of the first peak is 400 Å or less.

6. 6. The sputtering target according to claim 1, wherein the content of the second element is 3 to 70 atomic %.

7. 7. The sputtering target according to claim 1, wherein the oxygen content is 500 ppm or less.

8. 8. The sputtering target according to claim 1, wherein the carbon content is 200 ppm or less.

9. A method for producing a sputtering target of an alloy comprising ruthenium as a first element and any one element selected from boron, aluminum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten as a second element, comprising: a preparation step of preparing a raw material in which the first element and the second element have a predetermined element ratio; 1 x 10 －２ an atomization step of obtaining alloy powder by atomization using the raw materials in a vacuum atmosphere of 0 Pa or less, a nitrogen gas atmosphere containing 0 to 4 vol% of hydrogen gas, or an inert gas atmosphere containing 0 to 4 vol% of hydrogen gas; a sintering step of sintering the alloy powder by hot pressing, spark plasma sintering (SPS), or hot isostatic pressing (HIP) in a vacuum atmosphere of 50 Pa or less, a nitrogen gas atmosphere containing 0 to 4 vol% of hydrogen gas, or an inert gas atmosphere containing 0 to 4 vol% of hydrogen gas to obtain a sintered body, The method for producing a sputtering target, wherein the alloy powder obtained by the atomization method has a maximum major axis of 500 μm or less.

10. Between the atomizing step and the sintering step, The method for producing a sputtering target according to claim 9, further comprising a classification step of removing particles having a maximum major axis exceeding 500 μm from the alloy powder obtained by the atomization method.

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