Metal sputtering target, metal sputtering target structure, method for producing film using same, and method for producing metal sputtering target

Abstract

This metal sputtering target includes a metal having a body-centered cubic structure or a face-centered cubic structure. When the crystal orientation is analyzed from the sputtering surface normal direction (ND direction) through observation of a cross-section perpendicular to the sputtering surface of the metal sputtering target using an electron backscatter diffraction method, the proportion to all measurement points of measurement points with a plane orientation within 15° from the plane orientation in which the intensity on the inverse pole figure space obtained from said all measurement points is highest is 35 area% or more. When the crystal orientation distribution function of the metal sputtering target is represented using Euler angles (φ1, Φ, φ2) representing crystal orientation, in an orientation group of φ1: k° (0 ≤ k ≤ 90), Φ: x° (0 ≤ x ≤ 90), and φ2: y° (0 ≤ y ≤ 90), in all combinations of (x, y) with which the average value of orientation density within the range of 0 ≤ k ≤ 90 is 1.2 or more, the variation coefficient of the average value is 0.5 or less.

Description

Metal sputtering target, metal sputtering target structure, film manufacturing method using the same, and metal sputtering target manufacturing method

[0001] The present disclosure relates to a metal sputtering target, a metal sputtering target structure, a method for producing a film using the same, and a method for producing a metal sputtering target.

[0002] Sputtering targets are widely used as thin film forming materials for semiconductor wiring and lithography masks. As the integration density of semiconductors has increased in recent years, the thin films that make up these devices have also become finer. In particular, minute differences in the film thickness of thin films (film thickness distribution) have a significant impact on product yield.

[0003] It is known that in film formation by sputtering, the crystalline orientation of the sputtering target significantly affects the film thickness distribution during film formation. For example, Non-Patent Document 1 states that sputtered particles fly out in the closest-packed direction of the sputtering target. Furthermore, Non-Patent Document 2 reports that the closest-packed direction fluctuates due to lattice vibration caused by thermal disturbance, and that the lattice vibration expands due to high temperatures, i.e., film thickness uniformity deteriorates during film formation at high temperatures. Meanwhile, Patent Documents 1 and 2 report that film thickness uniformity can be improved by fabricating a sputtering target so that the closest-packed direction is oriented in the normal direction of the sputtering surface.

[0004] JP 2014-129599 A JP 2012-507626 A

[0005] Gottfried K. Wehner, Phys. Rev. 102, 690 (1956) F. Bouchard et al, J. Vac. Sci. Technol. A 11, 2765 (1993)

[0006] However, the sputtering targets described in Non-Patent Documents 1 and 2 and Patent Documents 1 and 2 only have their orientation controlled in the normal direction of the sputtering surface.

[0007] An object of the present disclosure is to provide at least one of a metal sputtering target suitable for forming a sputtering film with a uniform thickness by sputtering, a metal sputtering target structure, a film manufacturing method using the same, and a metal sputtering target manufacturing method.

[0008] In this disclosure, the inventors have investigated the improvement of the uniformity of the thickness of a film formed by sputtering, focusing on the crystalline structure of a metal sputtering target. As a result, the inventors have found that with conventional metal sputtering targets, anisotropy occurs in the launch angle of sputtered particles due to the in-plane anisotropy of the sputtering surface, resulting in non-uniform thickness of the sputtered film. As a result of further investigation, they have found that the uniformity of the thickness of the resulting sputtered film (thin film) can be improved by controlling the in-plane orientation of the metal sputtering target to a specific state.

[0009] That is, the present invention is as defined in the claims, and the gist of the present disclosure is as follows: [1] In a metal sputtering target containing a metal having a body-centered cubic structure or a face-centered cubic structure, when a cross section perpendicular to the sputtering surface of the metal sputtering target is observed using electron backscatter diffraction to analyze the crystal orientation from the normal direction (ND direction) of the sputtering surface, the proportion of measurement points having a plane orientation within 15° from the plane orientation with the highest intensity in an inverse pole figure space obtained from all measurement points to all measurement points is 35 area % or more, and A metal sputtering target in which a crystal coordinate system, with the

[100] orientation of the crystal as the X-axis, the

[010] orientation as the Y-axis, and the

[001] orientation as the Z-axis, is aligned with the orthogonal sample coordinate systems RD, TD, and ND of the sputtering target, and the crystal coordinate system is then rotated around the Z-axis by φ1, then rotated by Φ around the X-axis after the rotation, and then further rotated by φ2 around the Z-axis after the rotation, to express the crystal orientation distribution function of the metal sputtering target using Euler angles (φ1, Φ, φ2) that represent crystal orientation. In the orientation group of φ1:k° (0≦k≦90), Φ:x° (0≦x≦90), and φ2:y° (0≦y≦90), the average value of the orientation density in the range of 0≦k≦90 is 1.2 or more, and the coefficient of variation of the average value is 0.5 or less for all combinations of (x, y). [2] The metal sputtering target according to [1], wherein the ratio is 98 area % or less. [3] The metal sputtering target according to [1] or [2], wherein the coefficient of variation of the average value is 0.01 or more. [4] The metal sputtering target according to any one of [1] to [3], wherein the maximum value of the crystal orientation distribution function is 2.0 or more. [5] The metal sputtering target according to any one of [1] to [4], wherein the maximum value of the crystal orientation distribution function is 50 or less. [6] The metal sputtering target according to any one of [1] to [5], wherein the metal is one or more selected from the group consisting of chromium (Cr), iron (Fe), ruthenium (Ru), niobium (Nb), molybdenum (Mo), tantalum (Ta), vanadium (V), tungsten (W), aluminum (Al), copper (Cu), and nickel (Ni).[7] The metal sputtering target according to any one of [1] to [6], wherein the metal is one or more selected from the group consisting of chromium (Cr), ruthenium (Ru), molybdenum (Mo), and tungsten (W). [8] A metal sputtering target structure comprising the metal sputtering target according to any one of [1] to [7] and a backing plate. [9] A film manufacturing method using the metal sputtering target according to any one of [1] to [7] or the metal sputtering target structure according to [8].

[10] A method for manufacturing a metal sputtering target according to any one of [1] to [7], comprising: a pressurizing step of pressurizing an ingot made of a metal having a body-centered cubic structure or a face-centered cubic structure at a pressing temperature of 500°C or higher using a buffer member having a buffer layer to obtain a processed ingot; and a heat treatment step of treating the processed ingot at 900°C or higher.

[11] The method for manufacturing a metal sputtering target according to

[10] , wherein the buffer layer is a buffer layer having a coating.

[12] The method for producing a metal sputtering target according to

[10] or

[11] , wherein the buffer layer is a buffer layer having a graphite lubricant coating.

[0010] The present disclosure can provide at least one of a metal sputtering target capable of forming a sputtering film with a uniform thickness by sputtering, a metal sputtering target structure, a film manufacturing method using these, and a metal sputtering target manufacturing method.

[0011] 1 is a cross-sectional view showing an embodiment of a metal sputtering target structure according to the present disclosure, and FIG. 2 is a cross-sectional view showing an example of a film-coated substrate manufactured by the film manufacturing method according to the present disclosure.

[0012] The present disclosure will be described in detail with reference to the drawings showing one embodiment. The configurations and parameters disclosed in this specification can be arbitrarily combined, and the upper and lower limits of the values ​​disclosed in this specification can be arbitrarily combined. In addition, the same or equivalent components are designated by the same reference numerals throughout the drawings.

[0013] <<Metal Sputtering Target>> This embodiment relates to a metal sputtering target containing a metal having a body-centered cubic structure or a face-centered cubic structure, wherein, when a cross section perpendicular to the sputtering surface of the metal sputtering target is observed using electron backscatter diffraction and the crystal orientation is analyzed from the normal direction (ND direction) of the sputtering surface, the proportion of measurement points having an orientation (plane orientation) within 15° from the plane orientation with the highest intensity in an inverse pole figure space obtained from all measurement points to all measurement points is 35 area % or more, and The metal sputtering target has a crystal orientation distribution function of 0.5 or less for all combinations of (x, y) where the average value of the orientation density in the range of 0≦k≦90 is 1.2 or more in an orientation group of φ1:k° (0≦k≦90), Φ:x° (0≦x≦90), and φ2:y° (0≦y≦90). The crystal orientation distribution function of the metal sputtering target is expressed using Euler angles (φ1, Φ, φ2) that represent crystal orientations, when a crystal coordinate system, with the

[100] orientation of the crystal as the X-axis, the

[010] orientation as the Y-axis, and the

[001] orientation as the Z-axis, is rotated by φ1 around the Z-axis from a state where the coordinate system coincides with the orthogonal sample coordinate systems RD, TD, and ND of the sputtering target, and then rotated by Φ around the X-axis after the rotation, and then rotated by φ2 around the Z-axis after the rotation. The metal sputtering target of this embodiment is suitable for forming a sputtering film with a uniform thickness by sputtering.

[0014] This embodiment relates to a metal sputtering target containing a metal having a body-centered cubic structure or a face-centered cubic structure (hereinafter also referred to as "the target of this embodiment"), and may be a metal sputtering target containing a metal having a body-centered cubic structure (hereinafter also referred to as "bcc metal") or a metal sputtering target composed of a bcc metal. Furthermore, this embodiment may be a metal sputtering target containing a metal having a face-centered cubic structure (hereinafter also referred to as "fcc metal") or a metal sputtering target composed of an fcc metal.

[0015] The bcc metal is preferably one or more selected from the group consisting of chromium (Cr), iron (Fe), ruthenium (Ru), niobium (Nb), molybdenum (Mo), tantalum (Ta), vanadium (V), and tungsten (W), more preferably one or more selected from the group consisting of chromium, molybdenum, ruthenium, and tungsten, still more preferably one or more selected from the group consisting of chromium, molybdenum, and tungsten, and particularly preferably one or more selected from chromium and molybdenum. Chromium is preferred from the viewpoint of application of the sputtering film formed by the target of this embodiment to a light-shielding film material in mask blanks, while molybdenum is preferred from the viewpoint of application of the sputtering film formed by the target of this embodiment to a reflective layer material in EUV mask blanks.

[0016] The bcc metal may be an alloy, and examples of the alloy constituting the target of this embodiment include an alloy containing one or more selected from the group consisting of chromium, iron, ruthenium, niobium, molybdenum, tantalum, vanadium, and tungsten, an alloy containing one or more selected from the group consisting of chromium, molybdenum, ruthenium, and tungsten, an alloy containing one or more selected from the group consisting of chromium, molybdenum, and tungsten, an alloy containing chromium and molybdenum, an alloy containing chromium, and a chromium-molybdenum alloy.

[0017] The fcc metal is preferably one or more selected from the group consisting of aluminum (Al), copper (Cu) and nickel (Ni), and more preferably copper (Cu).

[0018] The fcc metal may be an alloy, and the alloy constituting the target of this embodiment is preferably one or more selected from the group consisting of aluminum (Al), copper (Cu), and nickel (Ni), and examples thereof include an alloy containing one or more selected from the group consisting of aluminum (Al) and copper (Cu), and further an alloy containing one or more selected from the group consisting of copper (Cu) and nickel (Ni).

[0019] Hereinafter, the target of this embodiment will be referred to as a "molybdenum sputtering target" when the metal contained in the metal sputtering target is molybdenum, or as a "chromium-molybdenum sputtering target" when the metal contained in the metal sputtering target is a chromium-molybdenum alloy.

[0020] The target of this embodiment may contain an amorphous phase as long as the generation of particles can be suppressed when the target of this embodiment is used.

[0021] The average crystal grain size of the metal contained in the target of this embodiment can be, for example, 200 μm or less, 150 μm or less, 100 μm or less, 80 μm or less, or 50 μm or less. The average crystal grain size can be, for example, 5 μm or more, 10 μm or more, 20 μm or more, or 30 μm or more. The average crystal grain size can be, for example, 5 μm or more to 200 μm or less, 10 μm or more to 150 μm or less, or 20 μm or more to 100 μm or less.

[0022] In this embodiment, the average crystal grain size is an average value of crystal grain sizes that can be determined by a method in accordance with JIS G 0551:2020 and Annex JC.

[0023] The target of this embodiment preferably has a low content of metal impurities, and for example, the purity of the target of this embodiment is preferably more than 99.6%, 99.9% or more, 99.99% (4N) or more, or 99.999% (5N) or more, and may be 100% or less or less than 100%. The purity of the target of this embodiment may be more than 99.6% and 100% or less, 99.9% or more and 100% or less, 99.9% or more and less than 100%, or 99.99% or more and less than 100%.

[0024] In this embodiment, the metal impurity content is the content of metal impurities measured by glow discharge mass spectrometry (hereinafter also referred to as "GDMS") in accordance with ASTM F 1593. Examples of metal impurities include metals other than bcc metals, and in metal materials made of specific bcc metals, metals other than these metals. For example, in the case of a molybdenum sputtering target, metals other than molybdenum are included, and in the case of a chromium-molybdenum sputtering target, metals other than chromium and molybdenum are included. The measurement sample may be a prismatic metal material measuring 10 to 25 mm x 10 to 25 mm x 0.5 to 15 mm. Prior to measurement, the measurement sample may be polished using SiC polishing paper (#800) until the Ra is 1.6 μm or less, followed by pretreatment by ultrasonic cleaning in pure water for 10 minutes, dehydration with alcohol, hot air drying, and vacuum packaging.

[0025] The oxygen content of the target of this embodiment is preferably 200 ppm by mass or less, and more preferably 150 ppm by mass or less, 30 ppm by mass or less, or 10 ppm by mass or less. This makes it easier to suppress particle generation when the target of this embodiment is used. The inclusion of oxygen is permitted as long as it is within a range in which particle generation is suppressed. For example, the oxygen content may be 0 ppm by mass or more, more than 0 ppm by mass, 1 ppm by mass or more, or 3 ppm by mass or more. The oxygen content may be 0 ppm by mass or more and 200 ppm by mass or less, more than 0 ppm by mass to 150 ppm by mass or less, or 1 ppm by mass or more and 30 ppm by mass or less.

[0026] The oxygen content of the target of this embodiment can be measured using a general oxygen / nitrogen analyzer (for example, ON736, manufactured by LECO Corporation).

[0027] The shape of the target in this embodiment is arbitrary, but is preferably a shape suitable for sputtering, and examples thereof include one or more shapes selected from the group consisting of a plate, a column, and a cylinder.

[0028] The area of ​​the sputtering surface of the target in this embodiment is not particularly limited, but from the viewpoint of widening the film formation area, it is preferable to use a sputtering surface area of ​​200 cm. ２ Above, 350cm ２or above 800cm ２ The area of ​​the sputtering surface is preferably 2000 cm or more. ２ Below, 1500cm ２ or less than 1200 cm ２ The area of ​​the sputtering surface is 200 cm ２ More than 2000cm ２ Below, 350cm ２ More than 2000cm ２ or less than 350cm ２ More than 1500cm ２ The following points can be mentioned.

[0029] <Orientation Ratio> In the target of this embodiment, when a cross section perpendicular to the sputtering surface of a metal sputtering target is observed using backscattered electron diffraction to analyze the crystal orientation from the normal direction (ND direction) of the sputtering surface, the plane orientation (oriented plane orientation) with the highest intensity in the inverse pole figure space obtained from all measurement points on the cross section is identified, and measurement points having orientations (plane orientations) within 15° of that plane orientation are extracted. The orientation ratio is calculated as the area ratio relative to all measurement points. If the orientation ratio is less than 35 area%, the thickness of the resulting film (sputtered film) will be nonuniform. In other words, if the orientation ratio is 35 area% or more, the thickness uniformity of the resulting film (sputtered film) will be improved. The orientation ratio is preferably 40 area% or more. The orientation ratio may be 50 area% or more, 60 area% or more, 70 area% or more, or 80 area% or more.

[0030] The orientation rate is preferably high, and examples thereof include less than 100 area%, 98 area% or less, 95 area% or less, 90 area% or less, 80 area% or less, 70 area% or less, and 60 area% or less. The orientation rate may be 35 area% or more and less than 100 area%, 40 area% or more and 98 area% or less, or 50 area% or more and 95 area% or less.

[0031] In this embodiment, the orientation rate can be determined from an SEM observation image obtained by scanning electron microscope-electron backscatter diffraction (hereinafter also referred to as "SEM-EBSD") measurement under the following conditions: Observation magnification: 10x Acceleration voltage: 20 kV Irradiation current: 100 μA Work distance: 10 mm Step width: 5 μm

[0032] That is, the SEM observation image is divided into a 5 μm x 5 μm grid to set the grid points, which are used as measurement points. Then, the orientation planes of all measurement points are identified, and the area of ​​the orientation planes is measured. Furthermore, the intensity in the inverse pole figure space obtained from each measurement point is calculated, and the plane orientation with the highest intensity is identified. Here, the intensity refers to the frequency of occurrence of a specific plane orientation relative to a state in which the specific plane orientation is completely random, and is a unitless parameter. For example, if the intensity of a specific plane orientation is "5", this means that the specific plane orientation appears five times more frequently than in a completely random state. Then, the orientation rate is calculated from the area ratio of measurement points having orientations (plane orientations) within 15° of this plane orientation to all measurement points. For example, if the plane orientation is the {111} plane, the orientation rate can be calculated from the following formula: Orientation rate ｛１１１｝ [Area %] = {total area of ​​measurement points with {111} plane orientation / total area of ​​all measurement points} × 100

[0033] SEM observation, identification of the orientation plane, and measurement of its area and the intensity of the inverse pole figure space obtained from each measurement point may be performed using a general SEM-EBSD device (e.g., JSM-IT800, manufactured by JEOL Ltd.) and its associated measurement / analysis program (e.g., AZtec, AZtec Crystal).

[0034] Prior to SEM-EBSD measurement, the measurement sample (metal sputtering target) may be mirror-polished with SiC polishing paper and buffed, and then the altered layer of the material may be removed by acid or plasma etching. For example, pretreatment may be performed by electrolytic etching with a 5% by volume aqueous solution of sulfuric acid.

[0035] <Crystal orientation distribution function> In the target of this embodiment, when a crystal coordinate system in which the

[100] orientation of the crystal is the X-axis, the

[010] orientation is the Y-axis, and the

[001] orientation is the Z-axis is aligned with the orthogonal sample coordinate systems RD, TD, and ND of the sputtering target, the crystal coordinate system is rotated around the Z-axis by φ1, then rotated by Φ around the X-axis after the rotation, and then further rotated by φ2 around the Z-axis after the rotation to express the crystal orientation distribution function of the metal sputtering target using Euler angles (φ1, Φ, φ2) that represent crystal orientation, in an orientation group of φ1:k° (0≦k≦90), Φ:x° (0≦x≦90), and φ2:y° (0≦y≦90), the average value of the orientation density in the range of 0≦k≦90 (hereinafter also referred to as the “average orientation density”) is 1.2 or more, the coefficient of variation of the average orientation density is 0.5 or less for all combinations of (x, y) (combinations of x and y).

[0036] Here, the Euler angles (φ1, Φ, φ2) are a set of angles that express the crystal orientation in the sample coordinate system of a metal sputtering target. The crystal coordinate system, with the

[100] orientation of the crystal as the X-axis, the

[010] orientation as the Y-axis, and the

[001] orientation as the Z-axis, is aligned with the orthogonal sample coordinate system RD, TD, and ND of the sputtering target. The crystal coordinate system is then rotated φ1 around the Z-axis, then rotated Φ around the X-axis after the rotation, and then rotated φ2 around the Z-axis after the rotation. The Euler angles (φ1, Φ, φ2) are expressed using the Bunge method. Here, "ND" is the normal direction of the sputtering surface (the direction perpendicular to the sputtering surface), and "TD" is the direction perpendicular to "ND" and "RD." "RD" varies depending on the shape of the sputtering surface of the target. For example, if the shape of the sputtering surface is rectangular, "RD" is the longitudinal direction of the rectangle. In this case, "TD" is the direction perpendicular to "ND" and "RD" and is also the width direction. If the shape of the sputtering surface is circular, "RD" is the direction along the diameter passing through the center of the circle.

[0037] If the coefficient of variation of the average orientation density is 0.5 or less, the in-plane anisotropy of the crystal structure is reduced. As a result, the film thickness uniformity during film formation is improved. On the other hand, when the crystal orientation distribution function is expressed in Euler angles, among all combinations of (x, y) in an orientation group of φ1:k° (0≦k≦90), Φ:x° (0≦x≦90), and φ2:y° (0≦y≦90), if the coefficient of variation of the average orientation density of any of the (x, y) combinations where the average orientation density in the range of 0≦k≦90 is 1.2 or more exceeds 0.5, the in-plane anisotropy of the crystal structure increases, and the thickness uniformity of the resulting film decreases. Such metal sputtering targets can only produce films with low film thickness uniformity. The coefficient of variation of the average orientation density can be calculated as follows: Coefficient of variation of the average orientation density = Standard deviation of the average orientation density / Mean value of the average orientation density The coefficient of variation of the average orientation density may be 0.4 or less, or 0.3 or less. The lower limit of the coefficient of variation of the average orientation density is not particularly limited, but may be 0.01 or more, 0.05 or more, 0.1 or more, or 0.2 or more. For molybdenum, the coefficient of variation of the average orientation density may be 0.01 or more and 0.5 or less, 0.01 or more and 0.4 or less, or 0.01 or more and 0.3 or less. For chromium, the coefficient of variation of the average orientation density may be 0.01 or more and 0.5 or less, 0.05 or more and 0.5 or less, or 0.1 or more and 0.5 or less.

[0038] The maximum value of the crystal orientation distribution function of the target of this embodiment is preferably 2.0 or more, and more preferably 2.5 or more. If the maximum value of the crystal orientation distribution function is 2.0 or more, the anisotropy in the launch angle of the sputtered particles is further reduced, making it easier to control the film thickness during sputtering. Examples of the upper limit of the maximum value of the crystal orientation distribution function include 50 or less, 40 or less, and 30 or less. The upper limit of the maximum value of the crystal orientation distribution function may be 2.0 or more and 50 or less, 2.0 or more and 40 or less, or 2.5 or more and 30 or less. The maximum value of the crystal orientation distribution function may also be the maximum value of the orientation density.

[0039] The maximum value of the crystal orientation distribution function in this embodiment is the maximum value of the crystal orientation distribution function (hereinafter also referred to as "ODF") obtained from an SEM observation diagram obtained by a method similar to that used to measure the orientation ratio. That is, the SEM observation diagram is analyzed, and the crystal orientations at all measurement points are expressed as Euler angles based on Bunge's notation (φ1, Φ, φ2). Next, for the Euler angles, the crystal orientation distribution function (ODF) is calculated using an expansion index of 22 and a Gaussian half-width of 5° as spherical harmonic functions. For the orientation groups φ1:k° (0≦k≦90), Φ:x° (0≦x≦90), and φ2:y° (0≦y≦90), the ODF is calculated at 5° intervals, and the maximum value is taken as the maximum value of the crystal orientation distribution function.

[0040] A general analysis program (for example, Aztec Crystal) may be used to analyze the crystal orientation of the SEM observation image and calculate the ODF.

[0041] <Method for Manufacturing Metal Sputtering Target> The target of the present embodiment may be manufactured by any method, but a preferred method includes a method for manufacturing a target, which includes a pressurizing step of pressurizing an ingot made of a metal having a body-centered cubic structure or a face-centered cubic structure at a pressurizing temperature of 500°C or higher using a buffer member having a buffer layer to obtain a processed ingot, and a heat treatment step of heat-treating the processed ingot at 900°C or higher.

[0042] In the pressing step, for example, an ingot made of a metal having a body-centered cubic structure or a face-centered cubic structure is pressed at a pressing temperature of 500° C. or higher and a pressing speed of less than 15 mm / s to obtain a processed ingot.

[0043] The ingot to be subjected to the pressurizing step may be an ingot made of a metal having a body-centered cubic structure or a face-centered cubic structure, and is preferably an ingot made of one or more selected from the group consisting of chromium (Cr), iron (Fe), ruthenium (Ru), niobium (Nb), molybdenum (Mo), tantalum (Ta), vanadium (V), tungsten (W), aluminum (Al), copper (Cu), and nickel (Ni), more preferably an ingot made of one or more selected from the group consisting of chromium, molybdenum, ruthenium, and tungsten, even more preferably an ingot made of one or more selected from the group consisting of chromium, molybdenum, and tungsten, even more preferably an ingot made of at least one of chromium and molybdenum, and particularly preferably an ingot made of molybdenum.

[0044] The ingot may be an ingot made of an alloy, and examples thereof include an ingot made of an alloy containing one or more selected from the group consisting of chromium, iron, ruthenium, niobium, molybdenum, tantalum, vanadium, tungsten, aluminum, copper, and nickel, an ingot made of an alloy containing one or more selected from the group consisting of chromium, molybdenum, tantalum, vanadium, and tungsten, an ingot made of an alloy containing one or more selected from the group consisting of chromium, molybdenum, and tungsten, an alloy containing chromium and molybdenum, an ingot made of an alloy containing molybdenum, and an ingot made of a chromium-molybdenum alloy.

[0045] The purity of the ingot to be subjected to the pressurizing step may be equivalent to that of the metal contained in the target, and it is preferable that the purity and oxygen content of the ingot to be subjected to the pressurizing step are similar to those of the target described above.

[0046] The relative density of the ingot to be subjected to the pressing step is preferably 99% or more or 99.5% or more. This tends to increase the strength of the resulting metal material. The relative density of the ingot can be, for example, 100% or less. The relative density of the ingot can be, for example, 99% to 100% or 99.5% to 100%.

[0047] The average crystal grain size of the ingot to be subjected to the pressing step is arbitrary, but can be, for example, more than 20 μm or 30 μm or more. The average crystal grain size of the ingot can be, for example, 2000 μm or less, 1000 μm or less, or 400 μm or less, and can be, for example, more than 20 μm and 2000 μm or less, more than 20 μm and 1000 μm or less, or 30 μm or more and 1000 μm or less.

[0048] The maximum value of the orientation distribution function of the ingot subjected to the pressurizing step can be, for example, 5.0 or less. The orientation distribution function can be determined in the same manner as the crystal orientation distribution function of the target. This improves the uniformity of the structure after the pressurizing step, and the in-plane orientation tends to be high. The maximum value of the orientation distribution function of the ingot can be, for example, 1.2 or more, 2.0 or more, or 2.5 or more, and can be, for example, 1.2 to 5.0, 2.0 to 5.0, or 2.5 to 5.0.

[0049] In order to prevent non-uniform deformation of the ingot and suppress in-plane anisotropy of the crystal structure, the ingot is pressurized using a buffer member having a buffer layer during the pressurization process. That is, during the processing process, the ingot may be pressurized while covered with two buffer members. Here, for example, one of the two buffer members is a first buffer member made of a buffer layer, and the other is a second buffer member having a buffer layer and a cylindrical side wall portion provided on the buffer layer. In this case, the ingot is pressurized while placed in a container formed using the first and second buffer members. The first and second buffer members are preferably welded together by electron beam welding or the like in a vacuum atmosphere. In this case, the atmosphere inside the container is preferably a vacuum atmosphere.

[0050] The material of the buffer layer may be any material that can suppress deformation of the surface, etc., where stress concentrates when pressure is applied together with the ingot during pressure processing. The buffer layer has a main body, and the material of the main body of the buffer layer may be any metal whose yield stress is within ±50% of the yield stress of the ingot. For example, for a chromium ingot whose yield stress is 400 MPa, a metal whose yield stress is 200 MPa or more and 600 MPa or less may be used. Specifically, examples include a buffer layer made of chromium-free steel, a buffer layer having a main body made of rolled steel, and a buffer layer having a main body made of carbon steel (SS400) or carbon steel (SN490B).

[0051] To prevent uneven deformation of the ingot, the total thickness of the buffer layers of the buffer members arranged on both sides of the ingot is preferably 30% or more, more preferably 40% or more, of the thickness of the ingot. The thickness of the buffer layer is not particularly limited, but examples thereof include 160% or less, 140% or less, or 100% or less of the thickness of the ingot to suppress deformation of the buffer layer itself due to pressure. The ratio of the thickness of the buffer layer to the thickness of the ingot is preferably 30% or more and 160% or less, more preferably 30% or more and 140% or less, and even more preferably 40% or more and 100% or less.

[0052] The buffer layer is preferably coated to prevent thermocompression bonding between the ingot and the buffer layer during processing. That is, the buffer layer preferably comprises a main body and a coating provided on the surface of the main body. Examples of buffer layers having a coating include a buffer layer having one or more selected from the group consisting of powder coating, glass coating, oil-based lubricant coating, and graphite lubricant coating. A buffer layer having a graphite lubricant coating is preferred because it is highly effective in preventing thermocompression bonding. The coating is preferably heat-treated in a non-oxidizing atmosphere. Heat treatment in a non-oxidizing atmosphere alters part of the coating, improving the heat resistance of the coating. Examples of non-oxidizing atmospheres include a vacuum atmosphere, an argon atmosphere, a nitrogen atmosphere, or an argon + nitrogen atmosphere, with a vacuum atmosphere being preferred. When the coating is a graphite lubricant coating, i.e., when the coating is obtained by heat treatment of a graphite lubricant, the heat treatment temperature can be, for example, 200°C or higher, 225°C or higher, 250°C or higher, or 300°C or higher, and 450°C or lower, 400°C or lower, or 350°C or lower. By setting the heat treatment temperature within the above range, the adhesion between the buffer layer and the ingot is improved, and thermocompression bonding during pressure treatment can be suppressed. Examples of heat treatment temperatures include 200°C to 450°C, 225°C to 400°C, or 250°C to 350°C. When the coating is obtained using a graphite lubricant, examples of the viscosity of the coating liquid containing the graphite lubricant include 10 Pa·s or more or 20 Pa·s or more. Viscosity may be measured using a general cylindrical rotational viscometer (e.g., a rotational viscometer VT-06 Viscotester, manufactured by Liontec Co., Ltd.) in accordance with JIS Z 8803. The upper limit of the viscosity is not particularly limited, but examples include 100 Pa·s or less or 50 Pa·s or less, and examples include 10 Pa·s to 100 Pa·s or 20 Pa·s to 50 Pa·s.

[0053] In the pressing step, the ingot is pressed at a pressing temperature of 500°C or higher. The pressing temperature is preferably 600°C or higher or 700°C or higher. In order to suppress the occurrence of defects such as cracks during the pressing treatment, the pressing temperature is preferably 1000°C or lower or 900°C or lower. The pressing temperature is preferably 500°C or higher and 1000°C or lower, more preferably 600°C or higher and 1000°C or lower, and even more preferably 700°C or higher and 900°C or lower.

[0054] The pressure treatment may be carried out by any method capable of applying pressure to the ingot, and examples thereof include one or more methods selected from the group consisting of forging, drawing, extrusion, and rolling.

[0055] In the pressure treatment, the ingot is preferably pressurized so that the ratio of the ingot's length in the X direction to its length in the Z direction (hereinafter also referred to as the "size ratio") is 0.5 or more or 0.6 or more, where the direction in which pressure is applied to the ingot is the Z direction and the direction perpendicular to the Z direction is the X direction. This makes it easier for the ingot to be uniformly deformed. Pressurizing the ingot so that the size ratio is 8 or less or 4 or less further suppresses crack generation due to deformation. The size ratio of the ingot before the pressure treatment is more preferably 0.5 or more and 8 or 0.6 or more and 4 or less. Note that, when the ingot is a polyhedron such as a rectangular parallelepiped, it is preferable that both the size ratio calculated from the ratio of the ingot's maximum length in the X direction to its length in the Z direction and the size ratio calculated from the ratio of the ingot's minimum length in the X direction to its length in the Z direction satisfy the above-mentioned values.

[0056] The pressure treatment in the pressure step is preferably performed two or more times, and more preferably three or more times. By performing the pressure treatment under the above conditions multiple times, strain can be introduced into the target without causing defects such as ingot cracking. As a result, a target with a high orientation area ratio (orientation rate) is more likely to be obtained. Since the surface and interior of the obtained target tend to have a more uniform structure, the pressure treatment is preferably performed 20 times or less. The pressure treatment is preferably performed two to 20 times, and more preferably three to 20 times.

[0057] The temperature of the ingot may decrease before and after the pressure treatment. When the pressure treatment is performed multiple times in the pressure step, it is preferable to heat the ingot before each pressure treatment to the pressure temperature before the pressure treatment, in order to prevent the temperature of the ingot from decreasing.

[0058] The total rolling reduction of the processed ingot after the pressurizing step is preferably 50% or more or 60% or more. The upper limit of the total rolling reduction can be, for example, 95% or less or 90% or less. The total rolling reduction is preferably 50% or more and 95% or less, more preferably 60% or more and 95% or less, and even more preferably 60% or more and 90% or less. The total rolling reduction can be calculated using the following formula: Total rolling reduction [%] = (1 - thickness of pressed ingot / thickness of ingot before processing step) x 100

[0059] In the heat treatment step, the processed ingot is preferably heat treated at a heat treatment temperature of 900° C. or higher. If the heat treatment temperature is lower than 900° C., it is difficult to align the orientation.

[0060] The heat treatment temperature is more preferably 1500° C. or higher. The heat treatment temperature does not need to be higher than necessary, and may be 2200° C. or lower, or 2000° C. or lower. The heat treatment temperature is preferably 900° C. or higher and 2200° C. or lower, and more preferably 1500° C. or higher and 2000° C. or lower.

[0061] The heat treatment atmosphere may be any atmosphere, an inert atmosphere, a reducing atmosphere, or a vacuum atmosphere, and is preferably an inert atmosphere, a reducing atmosphere, or a vacuum atmosphere, and more preferably a reducing atmosphere or a vacuum atmosphere.

[0062] The heat treatment time may be adjusted appropriately depending on the size of the processed ingot to be subjected to the heat treatment step, the performance of the heat treatment furnace, and the like, and may be, for example, from 1 hour to 5 hours.

[0063] In order to form the target into a desired shape, the manufacturing method of this embodiment may include a processing step of processing the processed ingot prior to the heat treatment step. The processing method may be any method, such as cutting.

[0064] Furthermore, in order to reduce the surface roughness of the target, the manufacturing method of this embodiment may further include a surface treatment step of surface-treating the metal material after the heat treatment step.

[0065] <<Metal Sputtering Target Structure>> As shown in Fig. 1 , a metal sputtering target structure (hereinafter also referred to as "target structure") 100 of this embodiment includes a target 10 and a backing plate 20. The target 10 is configured as the target described above. This target structure 100 is also suitable for forming a film with a uniform thickness by sputtering. The backing plate 20 may be made of any material that is capable of conducting electricity and dissipating heat during sputtering, and examples thereof include backing plates made of one or more selected from the group consisting of copper (Cu), aluminum (Al), titanium (Ti), and SUS.

[0066] The backing plate 20 may be bonded directly to the target 10, or may be bonded via a bonding material 30 as shown in Fig. 1. The bonding material 30 may be any known material, such as indium (In).

[0067] The target structure 100 of this embodiment can be manufactured by a manufacturing method including a bonding step of bonding the target 10 and the backing plate 20 together.

[0068] The bonding method in the bonding step may be any method that can bond the backing plate 20 and the target 10, and examples thereof include one or more methods selected from the group consisting of diffusion bonding, solder bonding, and friction stir welding.

[0069] <<Film Formation Method>> The film manufacturing method (film formation method) of this embodiment uses the target or target structure of this embodiment. That is, the target or target structure of this embodiment can be used in a film manufacturing method using the same. The film 202 is formed by a sputtering method. That is, the film manufacturing method of this embodiment is a method of manufacturing a film-coated substrate 200 by sputtering the target 10 of this embodiment to form a film 202 on a substrate 201 (see FIG. 2). The film 202 is obtained by the film manufacturing method of this embodiment. The film 202 may be a thin film or a sputtered film (sputtering film). The substrate 201 is not particularly limited, and examples thereof include a silicon substrate, a glass substrate, and a quartz substrate. The temperature of the substrate 201 (film formation temperature) is not particularly limited, and may be, for example, room temperature (25°C). The process gas used during film formation is not particularly limited as long as it is a gas species that causes sputtering by discharge, and may be, for example, argon. The gas pressure during film formation is not particularly limited, but may be, for example, 0.1 Pa or more and 1 Pa or less. The acceleration voltage during film formation is not particularly limited, but may be, for example, 1 kV or more and 3 kV or less. The film formation time is not particularly limited, but may be, for example, 10 minutes or more and 60 minutes or less. Sputtering can be performed using a general sputtering device.

[0070] Any method for producing the film (film formation method) may be used, but for example, a method for producing the film under the following conditions may be used: Ultimate vacuum: 1×10 －４ Pa Process gas: Argon (Ar) Gas partial pressure: 0.5 Pa Film formation temperature: Room temperature (25°C) Substrate: Si substrate Acceleration voltage: 2 kV

[0071] The present disclosure will be described below with reference to examples, but the present disclosure is not limited to the following examples.

[0072] (Orientation Ratio) The orientation ratio of the plane orientation was determined as follows. First, an SEM-EBSD device (device name: JSM-IT800, manufactured by JEOL Ltd.), a measurement program (software name: AZtec), and an analysis program (software name: AZtec Crystal) were used to obtain SEM observation images by SEM-EBSD measurement under the following conditions for the metal sputtering targets obtained in the following examples and comparative examples. Observation magnification: 10x Acceleration voltage: 20 kV Irradiation current: 100 μA Work distance: 10 mm Step width: 5 μm

[0073] The SEM observation image was then divided into a 5 μm × 5 μm grid to form grid points, and each grid point was used as a measurement point. The orientation plane and its area at all measurement points were measured, and the intensity in the inverse pole figure space obtained from each measurement point was determined, and the plane orientation with the highest intensity (oriented plane orientation) was identified. Measurement points with orientations (plane orientations) within 15° from the plane orientation were selected, and the orientation rate [area %] was calculated from the area ratio to all measurement points.

[0074] The SEM-EBSD measurement was performed on a metal sputtering target obtained as follows. That is, first, the radius of the circular sputtering surface (sputtering surface) of the disk-shaped target was defined as R, and a width of 3 mm was taken radially inward from a position 0.7R away from the center of the circle. A cross-sectional portion of 3 mm width × total target thickness t (mm) in a direction perpendicular to the sputtering surface was observed. The cross-sectional portion (the portion that would become the measurement surface) was mirror-polished using SiC polishing paper and buffing, and then pretreated by electrolytic etching with a 5% by volume aqueous sulfuric acid solution to obtain a measurement area. Then, SEM-EBSD measurement was performed on the measurement area.

[0075] (Crystal Orientation Distribution Function) Using the SEM observation diagram obtained in the orientation rate measurement, the measurement results were analyzed at all measurement points on the SEM observation diagram using an analysis program (Aztec Crystal). The crystal orientation at each measurement point was obtained and expressed as Euler angles. The Euler angles were expressed using Bunge's notation (φ1, Φ, φ2). Based on the Euler angles obtained at each measurement point, the analysis program (Aztec Crystal) was used to calculate the crystal orientation distribution function (ODF) using an expansion index of 22 and a Gaussian half-width of 5° as spherical harmonic functions. The obtained crystal orientation distribution function was calculated for the orientation groups φ1:k° (0≦k≦90), Φ:x° (0≦x≦90), and φ2:y° (0≦y≦90), and the maximum value and the average value of the orientation density in the range of k=0 to 90 for all (x, y) combinations were calculated. In calculating the maximum and average values ​​of the crystal orientation distribution function, x, y, and k were each output at intervals of 5°.

[0076] (Oxygen Content) The oxygen content was measured using an oxygen / nitrogen analyzer (device name: ON736, manufactured by LECO). As a measurement sample, a metal material cut into a prismatic shape of 4 mm x 4 mm x 5 mm was used.

[0077] (Area of ​​Sputtering Surface) The area of ​​the sputtering surface was calculated by measuring the diameter R of the sputtering surface using a vernier caliper and using the following formula: Area of ​​sputtering surface = π × (R / 2) ２ (Viscosity) The viscosity of the coating liquid was measured using a cylindrical rotational viscometer (Rotational Viscometer VT-06 Viscotester, manufactured by Liontec Co., Ltd.) in accordance with JIS Z 8803. Measurement temperature: room temperature (25°C) Rotation speed: 62.5 rpm

[0078] Example 1 210 kg of molybdenum powder (purity 5N) was sealed in a 350 mm x 350 mm x 350 mm soft iron can and subjected to HIP treatment under the following conditions: HIP treatment atmosphere: argon gas atmosphere HIP treatment temperature: 1250°C HIP treatment pressure: 150 MPa HIP treatment time: 5 hours

[0079] The obtained HIPed body was ground and cut to adjust the shape, to obtain a disk-shaped ingot having a diameter of 180 mm and a thickness of 50 mm (a dimension ratio of 3.6), which was used as the molybdenum material of this example. The ingot had an average crystal grain size of 22.7 μm and a maximum ODF of 3.7.

[0080] A first buffer member and a second buffer member were prepared as buffer members for the ingot. For the first buffer member, an oil-based lubricant containing 30% or more graphite (manufactured by Nippon Graphite Industries Co., Ltd., product name: Rolling Oil, viscosity: 24 Pa s) was mixed with water to prepare a coating liquid with a viscosity of 20 Pa s. The coating liquid was applied to the surface of a disc-shaped member (thickness 25 mm, diameter 240 mm) made of SS400, and heat-treated in a vacuum atmosphere at 300 ° C for 30 minutes to obtain a buffer layer. For the second buffer member, a cylindrical box-shaped buffer member was used, which was composed of a disc-shaped buffer layer (thickness 25 mm, diameter 240 mm) made of SS400 and a cylindrical side wall portion with a height of 55 mm extending from the peripheral portion of the surface of the buffer layer. The coating liquid was applied to the surface of the buffer layer and the inner surface of the side wall, and heat-treated in a vacuum atmosphere at 300 ° C for 30 minutes. The ingot was placed on the surface of the buffer layer of the second buffer member, and the first buffer member was placed on the side wall of the second buffer member so as to cover the ingot, forming a container. The inside of the container was evacuated, and the first buffer member and the second buffer member were welded together by electron beam welding, thereby achieving sealing. The thickness of the buffer layers placed on both sides of the ingot (the sum of the thickness of the buffer layer of the first buffer member and the thickness of the buffer layer of the second buffer member) was 100% of the thickness of the ingot.

[0081] The ingot placed in a cylindrical box-shaped buffer layer was heated to 800°C, and then subjected to a pressure treatment in which pressure was applied to the heated ingot in the thickness direction at a pressure rate of 7 mm / sec. That is, the pressure treatment was performed so that the length of the ingot in the direction in which pressure was applied (Z direction) was 50 mm and the length in the direction perpendicular to the Z direction (X direction) was 180 mm. This pressure treatment was repeated 16 times to obtain an ingot (processed ingot) with a diameter of 330 mm and a thickness of 15 mm (total rolling reduction rate: 85%). When the temperature of the ingot after each pressure treatment was 450°C or lower, the ingot was heated to 800°C and then subjected to the pressure treatment.

[0082] The processed ingot was treated in an argon atmosphere at 1500°C for 3 hours to obtain a disk-shaped molybdenum sputtering target having a diameter of 330 mm and a thickness of 15 mm, which was used as the molybdenum sputtering target of this example. The orientation plane orientation, orientation rate, and maximum value of ODF of this molybdenum sputtering target are shown in Table 1.

[0083] Example 2 A molybdenum sputtering target was produced in the same manner as in Example 1, except that a molybdenum ingot was obtained in the same manner as in Example 1, and the obtained ingot was ground and cut to adjust its shape to a diameter of 180 mm and a thickness of 55 mm (a dimension ratio of 3.3), the ingot was pressurized with the ratio of the thickness of the buffer layer to the thickness of the ingot set to 91%, and the total rolling reduction was set to 70% so that the orientation plane orientation, orientation rate, and maximum value of ODF would be as shown in Table 1.

[0084] Example 3 Chromium powder (purity 4N) was sealed in a 350 mm x 350 mm x 350 mm soft iron can and subjected to HIP treatment under the following conditions: HIP treatment atmosphere: argon gas atmosphere HIP treatment temperature: 1150°C HIP treatment pressure: 100 MPa HIP treatment time: 2 hours

[0085] The obtained HIPed body was ground and cut to adjust the shape, to obtain a disk-shaped chromium ingot having a diameter of 180 mm and a thickness of 60 mm. The ingot had an average crystal grain size of 116.4 μm and a maximum ODF of 1.3.

[0086] A pressed ingot was obtained in the same manner as in Example 1, except that the obtained ingot was ground and cut to adjust the shape to a diameter of 90 mm and a thickness of 60 mm (a dimension ratio of 1.5), the thickness of the buffer layer was set to 83% of the thickness of the ingot, and the pressurization treatment was performed eight times.

[0087] The processed ingot was treated in an argon atmosphere at 1600°C for 1 hour, and then ground and cut to adjust the shape, to obtain a chromium sputtering target, which was used as the chromium sputtering target of this example. The orientation plane orientation, orientation rate, and maximum value of ODF of this chromium sputtering target are shown in Table 1.

[0088] Example 4 A chromium ingot was obtained in the same manner as in Example 3, and the obtained ingot was ground and cut to adjust its shape to a diameter of 60 mm and a thickness of 90 mm (a dimension ratio of 0.67). A pressed ingot was obtained in the same manner as in Example 1, except that: SN490B was used instead of SS400 for the disk-shaped member; the ratio of the thickness of the buffer layer to the thickness of the ingot was set to 56%; the ingot temperature was set to 1000°C; the pressurization treatment was performed eight times; and the total rolling reduction was set to 70% so that the maximum values ​​of the orientation plane orientation, orientation rate, and ODF were as shown in Table 1.

[0089] The processed ingot was treated in an air atmosphere at 1000° C. for 1 hour to prepare a chromium sputtering target.

[0090] Example 5 A pressed ingot was obtained in the same manner as in Example 1, except that a chromium ingot was obtained in the same manner as in Example 3, and the obtained ingot was ground and cut to adjust the shape to 120 mm in diameter x 40 mm in thickness (size ratio 3.0), the heat treatment temperature of the buffer member was set to 400°C, the ratio of the thickness of the buffer layer to the thickness of the ingot was set to 125%, and the total rolling reduction was set to 70% so that the orientation plane orientation, orientation rate, and maximum value of ODF were as shown in Table 1. The obtained processed ingot was treated in air at 1000°C for 1 hour to produce a chromium sputtering target.

[0091] Example 6 A molybdenum sputtering target was produced in the same manner as in Example 1, except that the obtained HIP body was ground and cut to adjust the shape to a diameter of 180 mm and a thickness of 55 mm (a dimension ratio of 3.3), the heat treatment temperature of the buffer member was set to 250°C, the ratio of the thickness of the buffer layer to the thickness of the ingot was set to 91%, and the total rolling reduction was set to 70%, so that the orientation plane orientation, orientation rate, and maximum value of ODF were as shown in Table 1.

[0092] Example 7 A molybdenum sputtering target was produced in the same manner as in Example 1, except that the obtained HIP body was ground and cut to adjust the shape to a diameter of 180 mm and a thickness of 55 mm (a dimensional ratio of 3.3), a buffer layer was used in which the thickness of SS400 was increased from 25 mm to 10 mm, the ratio of the thickness of the buffer layer to the thickness of the ingot was set to 36%, and the total rolling reduction was set to 70%, so that the maximum values ​​of the orientation plane orientation, orientation rate, and ODF were as shown in Table 1.

[0093] Comparative Example 1 210 kg of molybdenum powder (purity 5N) was sealed in a 350 mm x 350 mm x 350 mm soft iron can and subjected to HIP treatment under the following conditions: HIP treatment atmosphere: argon gas atmosphere HIP treatment temperature: 1250°C HIP treatment pressure: 150 MPa HIP treatment time: 5 hours

[0094] The obtained HIP body was ground and cut to adjust the shape, to obtain a disk-shaped ingot having a diameter of 180 mm and a thickness of 50 mm.

[0095] A first buffer member and a second buffer member were prepared as buffer layers for the ingot. For the first buffer member, an oil-based lubricant containing 30% or more graphite (manufactured by Nippon Graphite Industries Co., Ltd., product name: Rolling Oil, viscosity: 24 Pa s) was mixed with water to prepare a coating liquid with a viscosity of 20 Pa s. The coating liquid was applied to the surface of a disc-shaped member (thickness 25 mm, diameter 240 mm) made of SS400, and heat-treated at 300 ° C. for 30 minutes in air. The second buffer member was a cylindrical box-shaped buffer member obtained by applying the coating liquid to the surface of the buffer layer and the inner surface of the side wall of a cylindrical member consisting of a disc-shaped buffer layer (thickness 25 mm, diameter 240 mm) made of SS400 and a cylindrical side wall portion with a height of 55 mm extending from the peripheral portion of the surface of the buffer layer, and then heat-treating at 300 ° C. for 30 minutes in air. The ingot was then placed on the surface of the buffer layer of the second buffer member, and the first buffer member was placed on the sidewall of the second buffer member to cover the ingot, forming a container. The inside of the container was evacuated, and the first and second buffer members were welded together by electron beam welding, thereby achieving sealing. The ratio of the thickness of the buffer layer to the thickness of the ingot was 100%. The resulting ingot was heated to 800°C, and then subjected to a pressure treatment in which pressure was applied to the heated ingot in the thickness direction at a pressure rate of 7 mm / s. This pressure treatment was repeated 16 times to obtain an ingot (processed ingot) with a diameter of 330 mm and a thickness of 15 mm (total reduction rate of 70%). When the temperature of the ingot after each pressure treatment was 450°C or lower, the ingot was heated to 800°C and then subjected to a pressure treatment.

[0096] The processed ingot was treated in an argon atmosphere at 1500°C for 3 hours to obtain a disk-shaped molybdenum sputtering target having a diameter of 330 mm and a thickness of 15 mm, which was used as the molybdenum sputtering target of this comparative example. The orientation plane orientation, orientation rate, and maximum value of ODF of this molybdenum sputtering target are shown in Table 1.

[0097] Comparative Example 2 A pressed ingot was obtained in the same manner as in Example 1, except that a chromium ingot was obtained in the same manner as in Example 3, and the chromium ingot was ground and cut to adjust the shape to a diameter of 200 mm and a thickness of 50 mm (size ratio of 4.0), a buffer member with an SS400 thickness of 7 mm was used instead of 25 mm, the ratio of the buffer layer thickness to the ingot thickness was set to 28%, and the total rolling reduction was set to 80% so that the orientation plane orientation, orientation rate, and maximum value of ODF were as shown in Table 1. The obtained processed ingot was treated in air at 1000°C for 1 hour to produce a chromium sputtering target.

[0098] Comparative Example 3 A pressed ingot was obtained in the same manner as in Example 1, except that a chromium ingot was obtained in the same manner as in Example 3, and the chromium ingot was ground and cut to adjust the shape to a diameter of 90 mm and a thickness of 30 mm (a dimension ratio of 3.0), no buffer member was used, the pressurization treatment was repeated eight times, the ratio of the thickness of the buffer layer to the thickness of the ingot was set to 167%, and the total rolling reduction was set to 70% so that the orientation plane orientation, orientation rate, and maximum value of ODF were as shown in Table 1. The obtained processed ingot was treated in air at 1000°C for 1 hour to produce a chromium sputtering target.

[0099] Comparative Example 4 A pressed ingot was obtained in the same manner as in Example 1, except that a chromium ingot was obtained in the same manner as in Example 3, and the chromium ingot was ground and cut to adjust the shape to a diameter of 80 mm and a thickness of 40 mm (a dimension ratio of 2.0), a buffer member made of cast iron (FC200, thickness 25 mm) instead of SS400 was used, the ratio of the buffer layer thickness to the ingot thickness was 167%, and the total rolling reduction was 80% so that the orientation plane orientation, orientation rate, and maximum value of ODF were as shown in Table 1. The obtained processed ingot was treated in air at 1000°C for 1 hour to produce a chromium sputtering target.

[0100] Comparative Example 5 A pressed ingot was obtained in the same manner as in Example 1, except that a chromium ingot was obtained in the same manner as in Example 3, and the chromium ingot was ground and cut to adjust the shape to 75 mm in diameter x 25 mm in thickness (size ratio 3.0), a BN-based mold release agent (manufactured by Advanced Technical Products, model number: ATP-R33) was used as the coating liquid, the ratio of the buffer layer thickness to the ingot thickness was set to 200%, and the total rolling reduction was set to 65% so that the orientation plane orientation, orientation rate, and maximum value of ODF were as shown in Table 1. The obtained processed ingot was treated in air at 1000°C for 1 hour to produce a chromium sputtering target.

[0101] Comparative Example 6 A pressed ingot was obtained in the same manner as in Example 1, except that a chromium ingot was obtained in the same manner as in Example 3, and the chromium ingot was ground and cut to adjust the shape to a diameter of 70 mm and a thickness of 30 mm (a dimension ratio of 2.3), the heat treatment temperature for the buffer member was set to 500°C, the ratio of the thickness of the buffer layer to the thickness of the ingot was set to 167%, and the total rolling reduction was set to 70% so that the orientation plane orientation, orientation rate, and maximum value of ODF were as shown in Table 1. The obtained processed ingot was treated in air at 1000°C for 1 hour to produce a chromium sputtering target.

[0102] Comparative Example 7: 210 kg of molybdenum powder (purity 4N) was sealed in a 350 mm x 350 mm x 350 mm soft iron can and subjected to HIP treatment under the following conditions: HIP treatment atmosphere: argon gas atmosphere; HIP treatment temperature: 1250°C; HIP treatment pressure: 150 MPa; HIP treatment time: 5 hours. The resulting HIPed body was subjected to plastic processing, grinding, and cutting to adjust the shape, resulting in a disk-shaped ingot measuring 180 mm in diameter and 50 mm in thickness (size ratio 3.6). This was used as the molybdenum material for this comparative example. The ingot had an average crystal grain size of 20.5 μm and a maximum ODF of 7.3. A pressed ingot was obtained in the same manner as in Example 1, except that the ingot was pressurized and the total rolling reduction was set to 70% so that the orientation plane orientation, orientation ratio, and maximum ODF values ​​were as shown in Table 1. The resulting processed ingot was treated in an argon atmosphere at 1500° C. for 3 hours to prepare a molybdenum sputtering target.

[0103] (Comparative Example 8) The obtained HIP body was ground and cut to adjust the shape to a diameter of 180 mm x thickness of 55 mm (dimension ratio 3.3), and as a coating liquid, an oil-based lubricant containing 30% or more graphite (manufactured by Nippon Graphite Industries Co., Ltd., product name: Rolling Oil, viscosity: 24 Pa s) was mixed with water to prepare a coating liquid with a viscosity of 2 Pa s, and the coating liquid was used, the ratio of the thickness of the buffer layer to the thickness of the ingot was 91%, and the total rolling reduction was 70%, so that the maximum values ​​of the orientation plane orientation, orientation rate, and ODF were as shown in Table 1. A pressurized ingot was obtained in the same manner as in Example 1. The obtained processed ingot was treated in an argon atmosphere at 1500 ° C. for 3 hours to produce a molybdenum sputtering target.

[0104] The evaluation results of the molybdenum sputtering targets and chromium sputtering targets obtained in the examples and comparative examples are shown in Table 1 below.

[0105] It was confirmed that the molybdenum and chromium sputtering targets of the examples all had an orientation rate of 35 area % or more, and the maximum ODF value was 2 or more. In contrast, the orientation rates of Comparative Examples 3 to 6 were all less than 35 area %.

[0106] Furthermore, in the molybdenum sputtering targets and chromium sputtering targets of Examples 1 to 7, the (x, y) values ​​with an average orientation density of 1.2 or more were 110 in Example 1, 35 in Example 2, 21 in Example 3, 157 in Example 4, 88 in Example 5, 38 in Example 6, and 36 in Example 7, and it was confirmed that the coefficients of variation for all of these values ​​were 0.5 or less. In contrast, in the molybdenum sputtering targets of Comparative Examples 1, 2, 4, 7, and 8, the coefficients of variation for (x, y) values ​​with an average orientation density of 1.2 or more sometimes exceeded 0.5.

[0107] Tables 2A and 2B show the average orientation density of Example 1, and Tables 3A and 3B show the coefficients of variation of (x, y) when the average orientation density of Example 1 is 1.2 or more. Tables 4A and 4B show the average orientation density of Example 2, and Tables 5A and 5B show the coefficients of variation of (x, y) when the average orientation density of Example 2 is 1.2 or more. Tables 6A and 6B show the average orientation density of Example 3, and Tables 7A and 7B show the coefficients of variation of (x, y) when the average orientation density of Example 3 is 1.2 or more. Tables 8A and 8B show the average orientation density of Example 4, and Tables 9A and 9B show the coefficients of variation of (x, y) when the average orientation density of Example 4 is 1.2 or more. Tables 10A and 10B show the average orientation density of Example 5, and Tables 11A and 11B show the coefficients of variation of (x, y) when the average orientation density of Example 5 is 1.2 or more. Tables 12A and 12B show the average orientation density of Example 6, and Tables 13A and 13B show the coefficients of variation of (x, y) when the average orientation density of Example 6 is 1.2 or more. Tables 14A and 14B show the average orientation density of Example 7, and Tables 15A and 15B show the coefficients of variation of (x, y) when the average orientation density of Example 7 is 1.2 or more. Tables 16A and 16B show the average orientation density of Comparative Example 1, and Tables 17A and 17B show the coefficients of variation of (x, y) when the average orientation density of Comparative Example 1 is 1.2 or more. Tables 18A and 18B show the average orientation density of Comparative Example 2, and Tables 19A and 19B show the coefficients of variation of (x, y) when the average orientation density of Comparative Example 2 is 1.2 or more. Tables 20A and 20B show the average orientation density of Comparative Example 3, and Tables 21A and 21B show the coefficients of variation of (x, y) when the average orientation density of Comparative Example 3 is 1.2 or more. Tables 22A and 22B show the average orientation density of Comparative Example 4, and Tables 23A and 23B show the coefficients of variation of (x, y) when the average orientation density of Comparative Example 4 is 1.2 or more. Tables 24A and 24B show the average orientation density of Comparative Example 5, and Tables 25A and 25B show the coefficients of variation of (x, y) when the average orientation density of Comparative Example 5 is 1.2 or more. Tables 26A and 26B show the average orientation density of Comparative Example 6, and Tables 27A and 27B show the coefficients of variation of (x, y) when the average orientation density of Comparative Example 6 is 1.2 or more.Tables 28A and 28B show the average orientation density of Comparative Example 7, and Tables 29A and 29B show the coefficients of variation of (x, y) when the average orientation density of Comparative Example 7 is 1.2 or more. Tables 30A and 30B show the average orientation density of Comparative Example 8, and Tables 31A and 31B show the coefficients of variation of (x, y) when the average orientation density of Comparative Example 8 is 1.2 or more. In Tables 3A and 3B, Tables 5A and 5B, Tables 7A and 7B, Tables 9A and 9B, Tables 11A and 11B, Tables 13A and 13B, Tables 15A and 15B, Tables 17A and 17B, Tables 19A and 19B, Tables 21A and 21B, Tables 23A and 23B, Tables 25A and 25B, Tables 27A and 27B, Tables 29A and 29B, and Tables 31A and 31B, "Not applicable" indicates a combination of (x, y) for which the average orientation density is less than 1.2.

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[0168] <Evaluation of Film Formation Characteristics> The molybdenum sputtering targets and chromium sputtering targets obtained in the examples and comparative examples were each machined and then bonded to an oxygen-free copper backing plate. Sputtering was performed using each target under the following conditions, and the film formation rate (film formation speed) was measured. Gas type: argon (Ar) Gas pressure: 0.5 Pa Acceleration voltage: 2 kV Substrate: Si substrate Substrate temperature: room temperature (25°C) Substrate rotation: none

[0169] The film formation rate was calculated using the following formula: Film formation rate [nm / min] = average film thickness [nm] / film formation time [min]

[0170] In the above formula, the average film thickness is the average value of the film thicknesses at the measurement points. The measurement points for the film thickness were (1) the center of the glass substrate (glass substrate having a sputtered film) after film formation, (2) six equally spaced points on the circumference of a concentric circle having a diameter equivalent to ¼ of the diameter of the substrate, (3) 13 equally spaced points on the circumference of a concentric circle having a diameter equivalent to ¼ of the diameter of the substrate, (4) 19 equally spaced points on the circumference of a concentric circle having a diameter equivalent to ¾ of the diameter of the substrate, and (5) 25 equally spaced points on the circumference of a concentric circle having a diameter equivalent to ¼ of the diameter of the substrate, for a total of 64 points. The film thickness at each measurement point was measured using a spectroscopic ellipsometer (device name: M-2000, manufactured by J.A. Woollam). The average value of the film thicknesses obtained at each measurement point was taken as the average film thickness. The "maximum value - minimum value" and "film thickness standard deviation σ" were calculated from the film thicknesses obtained at each measurement point. The film thickness variation coefficient was calculated using the film thickness standard deviation σ and the average film thickness using the following formula. The results are shown in Table 32. Film thickness variation coefficient = film thickness standard deviation σ / average film thickness

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[0172] This application is based on a Japanese patent application filed on August 17, 2023 (Patent Application No. 2023-133069) and a Japanese patent application filed on November 30, 2023 (Patent Application No. 2023-202660), the entire contents of which are incorporated by reference. In addition, all references cited herein are incorporated in their entirety.

[0173] 10...metal sputtering target, 20...backing plate, 30...bonding material, 100...metal sputtering target structure, 200...film-coated substrate, 201...substrate, 202...film.

Claims

1. In a metal sputtering target containing a metal having a body-centered cubic structure or a face-centered cubic structure, when a cross section perpendicular to the sputtering surface of the metal sputtering target is observed using electron backscatter diffraction to analyze the crystal orientation from the normal direction (ND direction) of the sputtering surface, the ratio of measurement points having a plane orientation within 15° of the plane orientation with the highest intensity in the inverse pole figure space obtained from all measurement points to all measurement points is 35 area % or more, and A metal sputtering target, wherein a crystal coordinate system, in which the [100] orientation of the crystal is the X-axis, the [010] orientation is the Y-axis, and the [001] orientation is the Z-axis, is aligned with the orthogonal sample coordinate systems RD, TD, and ND of the metal sputtering target, and then the crystal coordinate system is rotated around the Z-axis by φ1, then rotated Φ around the X-axis after the rotation, and then further rotated φ2 around the Z-axis after the rotation, to express a crystal orientation distribution function of the metal sputtering target using Euler angles (φ1, Φ, φ2) that represent crystal orientations. In the orientation group of φ1:k° (0≦k≦90), Φ:x° (0≦x≦90), and φ2:y° (0≦y≦90), the average value of the orientation density in the range of 0≦k≦90 is 1.2 or more, and the coefficient of variation of the average value is 0.5 or less for all combinations of (x, y).

2. The metal sputtering target according to claim 1, wherein said ratio is 98 area % or less.

3. The metal sputtering target according to claim 1 or 2, wherein the coefficient of variation of the average value is 0.01 or more.

4. A metal sputtering target according to any one of claims 1 to 3, wherein the maximum value of the crystal orientation distribution function is 2.0 or more.

5. A metal sputtering target according to any one of claims 1 to 4, wherein the maximum value of the crystal orientation distribution function is 50 or less.

6. The metal sputtering target according to any one of claims 1 to 5, wherein the metal is one or more selected from the group consisting of chromium (Cr), iron (Fe), ruthenium (Ru), niobium (Nb), molybdenum (Mo), tantalum (Ta), vanadium (V), tungsten (W), aluminum (Al), copper (Cu), and nickel (Ni).

7. A metal sputtering target according to any one of claims 1 to 6, wherein the metal is one or more selected from the group consisting of chromium (Cr), ruthenium (Ru), molybdenum (Mo) and tungsten (W).

8. A metal sputtering target structure comprising: the metal sputtering target according to any one of claims 1 to 7; and a backing plate.

9. A method for producing a film, comprising using the metal sputtering target according to any one of claims 1 to 7 or the metal sputtering target structure according to claim 8.

10. A method for manufacturing a metal sputtering target according to any one of claims 1 to 7, comprising a pressurizing step in which an ingot made of a metal having a body-centered cubic structure or a face-centered cubic structure is pressurized at a pressing temperature of 500°C or higher using a buffer member having a buffer layer to obtain a processed ingot, and a heat treatment step in which the processed ingot is treated at a temperature of 900°C or higher.

11. The method of making a metal sputtering target according to claim 10, wherein the buffer layer is a buffer layer having a coating.

12. The method of claim 10 or 11, wherein the buffer layer is a buffer layer having a graphite lubricant coating.

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