Aluminum-scandium alloy sputtering target and method for manufacturing the same

Abstract

This invention discloses an aluminum-scandium alloy sputtering target and its preparation method. The aluminum-scandium alloy sputtering target is substantially composed of 10 at% to 50 at% scandium and 90 at% to 50 at% aluminum. The aluminum-scandium alloy sputtering target has a microstructure comprising a metallic aluminum matrix and a mesometallic aluminum-scandium phase within the metallic aluminum matrix, wherein the mesometallic aluminum-scandium phase includes Al3Sc, Al2Sc, or AlSc. The scandium content difference between any two different locations on the surface of the aluminum-scandium alloy sputtering target is less than or equal to 1 at%, and the aluminum-scandium grain size difference between any two different locations on the surface of the aluminum-scandium alloy sputtering target is less than or equal to 13 μm.

Description

Technical Field

[0001] This invention relates to an alloy sputtering target and its preparation method, particularly to an aluminum-scandium alloy sputtering target and its preparation method. Background Technology

[0002] As the frequency bands for next-generation communication filters such as 5G / 6G / WiFi 7 are gradually shifted from N41 to N77 globally, the demand for aluminum-scandium alloy targets is increasing. High-scandium aluminum-scandium alloy targets can improve the piezoelectric coefficient and electromechanical coupling coefficient and reduce signal transmission loss, and their demand is also increasing.

[0003] Due to the significant differences in melting point and density between aluminum and scandium, the fabrication of aluminum-scandium alloy sputtering targets is difficult and the composition is not easily uniform. Currently, aluminum-scandium alloy sputtering targets are typically prepared through vacuum melting, casting, and hot rolling processes. With higher scandium content and a higher melting point, the hot rolling process can form hard and brittle aluminum-scandium dielectric compounds, making the aluminum-scandium alloy sputtering targets difficult to process and shape. Furthermore, the surface of aluminum-scandium alloy sputtering targets is prone to oxidation at high temperatures, resulting in excessively high oxygen content and affecting the coating quality. Summary of the Invention

[0004] This invention provides an aluminum-scandium alloy sputtering target that achieves small and uniform grain size, low oxygen content, and / or uniform component mixing without post-heat treatment, and its preparation method.

[0005] One embodiment of the present invention provides an aluminum-scandium (Al-Sc) alloy sputtering target, which is substantially composed of 10 at% to 50 at% scandium and 90 at% to 50 at% aluminum. The aluminum-scandium alloy sputtering target includes a microstructure. The microstructure includes a metallic aluminum matrix and a mesometallic aluminum-scandium phase within the metallic aluminum matrix, the mesometallic aluminum-scandium phase including Al3Sc, Al2Sc, or AlSc. The difference in scandium content between any two different locations on the surface of the aluminum-scandium alloy sputtering target is less than or equal to 1 at%, and the difference in aluminum-scandium grain size between any two different locations on the surface of the aluminum-scandium alloy sputtering target is less than or equal to 13 μm.

[0006] One embodiment of the present invention provides an aluminum-scandium alloy sputtering target, prepared by a method comprising: providing aluminum and scandium with an atomic ratio of 90:10 to 50:50 in a melting tank; performing a first vacuum arc melting process in an inert gas environment to form a plurality of alloy ingots; arranging the plurality of alloy ingots in a melting tank, wherein the distance between two adjacent alloy ingots is less than or equal to 5 mm; performing a second vacuum arc melting process in an inert gas environment to melt the plurality of alloy ingots to form an aluminum-scandium alloy target blank; and cooling the aluminum-scandium alloy target blank to form an aluminum-scandium alloy sputtering target, wherein the average cooling rate of the aluminum-scandium alloy target blank is greater than or equal to 5 °C / min and less than 24 °C / min. The purity of aluminum is greater than or equal to 4N and the purity of scandium is greater than or equal to 4N.

[0007] Another aspect of the present invention provides a method for preparing an aluminum-scandium alloy sputtering target, comprising: providing aluminum and scandium with an atomic ratio of 90:10 to 50:50 in a melting tank; performing a first vacuum arc melting process in an inert gas environment to form a plurality of alloy ingots from the aluminum-scandium alloy; arranging the plurality of alloy ingots in a melting tank, wherein the distance between two adjacent alloy ingots is less than or equal to 5 mm; performing a second vacuum arc melting process in an inert gas environment to melt the plurality of alloy ingots to form an aluminum-scandium alloy target blank; and cooling the aluminum-scandium alloy target blank to form an aluminum-scandium alloy sputtering target, wherein the average cooling rate of the aluminum-scandium alloy target blank is greater than or equal to 5 °C / min and less than 24 °C / min. The purity of the aluminum is greater than or equal to 4N and the purity of the scandium is greater than or equal to 4N. Attached Figure Description

[0008] To make the objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0009] Figure 1 This is a flowchart of a method for preparing an aluminum-scandium alloy sputtering target according to an embodiment of the present invention.

[0010] Figure 2A This is a top view schematic diagram of an aluminum-scandium alloy sputtering target according to an embodiment of the present invention.

[0011] Figure 2B This is a side view schematic diagram of an aluminum-scandium alloy sputtering target according to an embodiment of the present invention.

[0012] Figure 3 The image shows the XRD pattern of an aluminum-scandium alloy sputtering target according to an embodiment of the present invention.

[0013] Figure 4 The image shows the XRD pattern of an aluminum-scandium alloy sputtering target according to another embodiment of the present invention.

[0014] In the attached figures, the following labels are used:

[0015] 1, 2, 3, 4, 5: loci

[0016] S101, S103, S105, S107, S109: Steps

[0017] BS: Back

[0018] FS: Front Detailed Implementation

[0019] It will be further understood that when "comprising" and / or "including" is used in this specification, it specifically refers to the presence of the stated feature, integer, step, operation, component, element, and / or group thereof, but does not exclude the presence or addition of one or more other feature, integer, step, operation, component, element, and / or group thereof. When the singular form "a" is used in this specification, it is intended to include the multiple forms as well, unless the context clearly indicates otherwise.

[0020] It will be understood that although the terms "first," "second," etc., may be used in this document to describe various steps, components, areas, layers, and / or parts, these steps, components, areas, layers, and / or parts should not be limited by these terms. These terms are used only to distinguish one step, component, area, layer, or part from another step, component, area, layer, or part.

[0021] It will be understood that the methods described herein comprise multiple steps, and additional steps may be provided before, during, and / or after said multiple steps. Some of the said steps may be replaced or omitted in different embodiments. Although some embodiments discussed are performed in a particular order, these steps may still be performed in another logical order.

[0022] In this paper, the expressions "a to b" or "a ~ b" used to represent specific numerical ranges are defined as "≥a and ≤b". "at%" in this paper is based on a total of 100 at% of all atoms. For example, "10 at% to 50 at% scandium" in this paper means that scandium comprises 10% to 50% of the total number of atoms.

[0023] One embodiment of the present invention provides an aluminum-scandium (Al-Sc) alloy sputtering target, substantially composed of 10 at% to 50 at% scandium and 90 at% to 50 at% aluminum alloy. The aluminum-scandium alloy sputtering target includes a microstructure. The microstructure includes a metallic aluminum matrix and a mesometallic aluminum-scandium phase within the metallic aluminum matrix, the mesometallic aluminum-scandium phase including Al3Sc, Al2Sc, or AlSc. The scandium content difference between any two different locations on the aluminum-scandium alloy sputtering target is less than or equal to 1 at%, and the aluminum-scandium grain size difference between any two different locations on the surface of the aluminum-scandium alloy sputtering target is less than or equal to 13 μm. The oxygen content of the aluminum-scandium alloy sputtering target is less than or equal to 100 ppm.

[0024] In this invention, the aluminum-scandium alloy sputtering target may contain 10 at% to 50 at% scandium and 90 at% to 50 at% aluminum. In some embodiments, the aluminum-scandium alloy sputtering target may also include unavoidable impurities. In some embodiments, the aluminum-scandium alloy sputtering target may be formed from aluminum and scandium through a melting process, but the invention is not limited thereto. In some embodiments, the aluminum-scandium alloy sputtering target may contain 10 at% to 45 at% scandium and 90 at% to 55 at% aluminum. In some embodiments, the aluminum-scandium alloy sputtering target may be composed of 10 at% to 40 at%, 15 at% to 45 at%, 15 at% to 40 at%, or 15 at% to 35 at% scandium. In some embodiments, the alloy used to form the aluminum-scandium alloy sputtering target may consist of 60 at% to 90 at%, 55 at% to 85 at%, 60 at% to 85 at%, or 75 at% to 85 at% aluminum.

[0025] The aluminum-scandium alloy sputtering target of the present invention may include a monometallic aluminum-scandium phase. The properties of the aluminum-scandium alloy sputtering target (e.g., coefficient of thermal expansion and mechanical properties) can be controlled by the monometallic aluminum-scandium phase. In some embodiments, the microstructure of the aluminum-scandium alloy sputtering target includes one or more monometallic aluminum-scandium phases, and each monometallic aluminum-scandium phase may respectively include Al3Sc, Al2Sc, or AlSc. In some embodiments, the monometallic aluminum-scandium phase in the microstructure of the aluminum-scandium alloy sputtering target is uniformly distributed in the aluminum matrix.

[0026] Scandium is uniformly distributed throughout the aluminum-scandium alloy sputtering target. Specifically, the difference in scandium content throughout the entire aluminum-scandium alloy sputtering target is less than or equal to 1 at%. That is, the difference in scandium content measured at any two different locations within the entire aluminum-scandium alloy sputtering target will not exceed 1 at.

[0027] In some embodiments, the aluminum-scandium alloy sputtering target may include an average aluminum-scandium grain size of less than 60 μm. A smaller aluminum-scandium grain size results in higher sputtering uniformity using the aluminum-scandium alloy sputtering target, and a lower defect density and higher compactness of the sputtered film. In this invention, "average aluminum-scandium grain size" refers to the average of the aluminum-scandium grain size measured at five locations on one side of the aluminum-scandium alloy sputtering target: the center point, the upper edge, the lower edge, the left edge, and the right edge. In some embodiments, the average aluminum-scandium grain size of the aluminum-scandium alloy sputtering target may be less than or equal to 60 μm, less than or equal to 55 μm, or less than or equal to 50 μm. In some embodiments, the average aluminum-scandium grain size of the aluminum-scandium alloy sputtering target may be greater than or equal to 10 μm, greater than or equal to 15 μm, or greater than or equal to 17 μm. In some embodiments, the average aluminum-scandium alloy sputtering target may have an average aluminum-scandium grain size greater than or equal to 10 μm and less than 60 μm, such as 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm or 55 μm.

[0028] In some embodiments, the aluminum scandium grain size in the aluminum scandium alloy sputtering target is uniform. For example, the difference in aluminum scandium grain size on the surface of the aluminum scandium alloy sputtering target is less than or equal to 13 μm. That is, the difference in aluminum scandium grain size measured at two different locations on the surface of the aluminum scandium alloy sputtering target will not exceed 13 μm. In some embodiments, the difference in aluminum scandium grain size in the aluminum scandium alloy sputtering target is less than or equal to 10 μm.

[0029] In some embodiments, the oxygen content of the aluminum-scandium alloy sputtering target may be less than 100 ppm. The lower the oxygen content in the aluminum-scandium alloy sputtering target, the better the coating quality. In some embodiments, the oxygen content of the aluminum-scandium alloy sputtering target may be less than or equal to 90 ppm, 80 ppm, 70 ppm, or 60 ppm.

[0030] Another aspect of the present invention provides a method for preparing an aluminum-scandium alloy sputtering target and an aluminum-scandium alloy sputtering target obtained by the method. Figure 1 This is a flowchart illustrating a method for preparing an aluminum-scandium alloy sputtering target according to an embodiment of the present invention. Figure 1As shown, the method for preparing the aluminum-scandium alloy sputtering target of the present invention includes: step S101 of providing pure aluminum and pure scandium with an atomic ratio of 90:10 to 50:50 in a melting tank; step S103 of performing a first vacuum arc melting process to form a plurality of alloy ingots from pure aluminum and pure scandium; step S105 of arranging the plurality of alloy ingots in a melting tank, wherein the distance between two adjacent alloy ingots is less than or equal to 5 mm; step S107 of performing a second vacuum arc melting process to melt the plurality of alloy ingots to form an aluminum-scandium alloy target blank; and step S109 of cooling the aluminum-scandium alloy target blank to form an aluminum-scandium alloy sputtering target. Further, in step S107, the average cooling rate of the aluminum-scandium alloy target blank is greater than or equal to 5 °C / min and less than 24 °C / min. The purity of the pure aluminum is greater than or equal to 4N, and the purity of the pure scandium is greater than or equal to 4N.

[0031] In step S101, pure aluminum and pure scandium with an atomic ratio of 90:10 to 50:50 are provided in the melting tank. By providing aluminum and scandium in the above ratio, the subsequently formed aluminum-scandium alloy sputtering target can have a smaller aluminum-scandium grain size. In some embodiments, the atomic ratio of aluminum to scandium can be 88:12 to 56:44, 85:15 to 55:45, or 80:20 to 60:40. In some embodiments, the melting tank may include a vacuum arc melting furnace, but the present invention is not limited thereto.

[0032] The first vacuum arc melting process in step S103 can be performed after step S101 in an inert gas environment to form multiple alloy ingots. In some embodiments, the first vacuum arc melting process in step S103 may include generating a first arc in a melting tank (e.g., a vacuum arc melting furnace) in an argon atmosphere of 100–250 Torr with a first voltage of 10–30 V and a first current of 200–600 A. In some embodiments, the first vacuum arc melting process is performed in an argon atmosphere of 150–220 Torr, such as 160 Torr, 180 Torr, or 200 Torr, but the invention is not limited thereto. In some embodiments, the first arc in the first vacuum arc melting process is generated with a first voltage of 15–25 V or 18–20 V and a first current of 250–600 A, but the invention is not limited thereto.

[0033] In some embodiments, the method may further include performing a purification process before the first vacuum arc melting process in step S103. Specifically, the purification process may include evacuating the interior of the vacuum arc melting furnace to 3 × 10⁻⁶ ppm after placing aluminum and scandium in the furnace and closing the furnace chamber door. -2Torr, followed by the introduction of argon gas to approximately 50–60 Torr. The purification process can be performed one or more times as needed. For example, in some embodiments, the purification process can be repeated 3 to 4 times. After the purification process, the cavity of the vacuum arc melting furnace can be evacuated to 2 × 10⁻⁶ Torr. -2 Torr, then 100-250 Torr of argon gas is injected to perform the first vacuum arc melting process in step S103.

[0034] The alloy ingot is formed by the first vacuum arc melting process in step S103. The alloy ingot formed in step S103 can be removed after cooling. In some embodiments, the alloy ingot formed in step S103 can be removed after cooling by injecting 500 Torr of argon gas into the cavity of the vacuum arc melting furnace, but the present invention is not limited thereto.

[0035] The alloy ingot formed in step S103 may include 10 at% to 50 at% scandium and 50 at% to 90 at% aluminum. In some embodiments, the alloy ingot may include 10 at% to 45 at%, 10 at% to 40 at%, 15 at% to 45 at%, 15 at% to 40 at%, or 15 at% to 35 at% scandium. In some embodiments, the alloy ingot may include 60 at% to 90 at%, 55 at% to 85 at%, 65 at% to 85 at%, or 75 at% to 85 at% aluminum. In some embodiments, the alloy ingot may have a weight of 75 to 175 g, for example 80 g, 90 g, 100 g, 110 g, 130 g, or 150 g.

[0036] The alloy ingots formed in multiple steps S103 are placed in a melting tank in step S105. The number of alloy ingots placed depends on the size of the melting tank. In some embodiments, the melting tank may include a vacuum arc melting furnace. Specifically, in some embodiments, 3 to 4 alloy ingots formed in step S103 may be uniformly arranged in the melting tank to perform the second vacuum arc melting process in step S107, wherein the distance between two adjacent alloy ingots may be less than or equal to 5 mm.

[0037] The second vacuum arc melting process in step S107 is performed after step S105. In some embodiments, the second vacuum arc melting process in step S107 may be performed in an inert gas environment to melt multiple alloy ingots to form an aluminum-scandium alloy target blank. In some embodiments, the second vacuum arc melting process in step S107 includes generating a second arc in a melting tank (e.g., a vacuum arc melting furnace) under an argon atmosphere of 100–250 Torr, with a second voltage of 10–30 V and a second current of 200–600 A. In some embodiments, the second vacuum arc melting process is performed under an argon atmosphere of 150–220 Torr, such as 160 Torr, 180 Torr, or 200 Torr, but the invention is not limited thereto. In some embodiments, the second arc in the second vacuum arc melting process is generated with a second voltage of 15–25 V or 18–20 V and a second current of 250–600 A, but the invention is not limited thereto. The second vacuum arc melting process in step S107 can melt the edges of the multiple alloy ingots formed in step S103 into a molten solution to join the surrounding alloy ingots, thereby forming an aluminum-scandium alloy target blank.

[0038] In some embodiments, the method may further include performing a purification process between steps S105 and S107. Specifically, the purification process may include, after step S105, closing the cavity door of the vacuum arc melting furnace and evacuating the interior of the vacuum arc melting furnace to 3×10⁻⁶ m³ / h. -2 Torr, followed by the introduction of argon gas to approximately 50–60 Torr. The purification process can be performed one or more times as needed. For example, in some embodiments, the purification process can be repeated 3 to 4 times. After the purification process, the cavity of the vacuum arc melting furnace can be evacuated to 2 × 10⁻⁶ Torr. -2 Torr, then 100-250 Torr of argon gas is injected to perform the second vacuum arc melting process in step S107.

[0039] After cooling the aluminum-scandium alloy target blank formed in step S107 at an average cooling rate greater than or equal to 5°C / min and less than 24°C / min in step S109, it is removed from the vacuum arc melting furnace to obtain the aluminum-scandium alloy sputtering target of the present invention. Cooling the aluminum-scandium alloy target blank formed in step S107 at an average cooling rate within the above range in step S109 can prevent cracks from forming in the obtained aluminum-scandium alloy sputtering target. Accordingly, the aluminum-scandium alloy sputtering target prepared by the preparation method of the aluminum-scandium alloy sputtering target of the present invention may not have cracks visible to the naked eye. In some embodiments, the average cooling rate in step S109 may be greater than or equal to 6°C / min and less than or equal to 20°C / min or greater than or equal to 6°C / min and less than or equal to 15°C / min.

[0040] In some embodiments, the aluminum-scandium alloy sputtering target prepared by the method of the present invention may include a microstructure. The microstructure includes a metallic aluminum matrix and a monometallic aluminum-scandium phase within the metallic aluminum matrix, wherein the monometallic aluminum-scandium phase includes Al3Sc, Al2Sc, or AlSc. The microstructure may include one or more monometallic aluminum-scandium phases, and each monometallic aluminum-scandium phase includes Al3Sc, Al2Sc, or AlSc. In some embodiments, the monometallic aluminum-scandium phase in the microstructure of the aluminum-scandium alloy sputtering target is uniformly distributed within the metallic aluminum matrix. Scandium is uniformly distributed throughout the entire aluminum-scandium alloy sputtering target. For example, in some embodiments, the difference in scandium content between any two different locations on the surface of the aluminum-scandium alloy sputtering target is less than or equal to 1 at%, and the difference in aluminum-scandium grain size between any two different locations on the surface of the aluminum-scandium alloy sputtering target is less than or equal to 13 μm.

[0041] In some embodiments, the aluminum-scandium alloy sputtering target prepared by the method of the present invention may include an average aluminum-scandium grain size of less than 60 μm. In some embodiments, the average aluminum-scandium grain size may be less than or equal to 58 μm, less than or equal to 55 μm, or less than or equal to 50 μm. In some embodiments, the average aluminum-scandium grain size may be greater than or equal to 10 μm, greater than or equal to 15 μm, or greater than or equal to 17 μm. In some embodiments, the average aluminum-scandium grain size may be greater than or equal to 10 μm and less than 60 μm, greater than or equal to 15 μm and less than or equal to 55 μm, or greater than or equal to 15 μm and less than or equal to 50 μm.

[0042] In some embodiments, the oxygen content of the aluminum-scandium alloy sputtering target prepared by the method of the present invention can be less than 100 ppm. The lower the oxygen content in the aluminum-scandium alloy sputtering target, the better the coating quality. In some embodiments, the oxygen content of the aluminum-scandium alloy sputtering target prepared by the method of the present invention can be less than or equal to 90 ppm, 80 ppm, 70 ppm, or 60 ppm.

[0043] In summary, in some embodiments, the aluminum-scandium alloy sputtering target prepared by the method of the present invention not only does not have visible cracks, but also has advantages such as small and uniform grain size, low oxygen content, and / or uniform composition without the need for post-heat treatment.

[0044] The following specific embodiments are provided to further illustrate the features and advantages of the present invention. However, those skilled in the art should understand that the present invention is not limited to the specific embodiments disclosed below.

[0045] Example 1

[0046] The copper mold is fixed to a water-cooling tank, with water continuously flowing through it to aid heat dissipation. Next, aluminum ingots with a purity of 4N or higher and scandium powder are placed in the melting tank inside the copper mold at an atomic ratio of 86.4:13.6, and the chamber door is closed. The interior of the vacuum arc melting furnace is evacuated to 3×10⁻⁶. -2 After Torr, argon gas is introduced into the cavity of the vacuum arc melting furnace to approximately 50–60 Torr, then evacuated. This process is repeated 3–4 times until the pressure is reduced to 2 × 10⁻⁶. -2 The pressure is increased to approximately 180 Torr, and argon gas is injected. First, a pure titanium ingot is melted to check for residual oxygen (a yellow surface indicates oxidation). After confirming the ingot is normal, the aluminum ingot and scandium powder are melted using a first vacuum arc melting process. This first vacuum arc melting process involves generating an arc with a voltage of 20V and a current of 400A in an argon atmosphere at a chamber pressure of 180 Torr to form three alloy ingots, each weighing approximately 125g. The alloy ingots are then removed after being cooled with water under a copper mold until they regain their original metallic color and the internal temperature of the chamber decreases.

[0047] Arrange the aforementioned alloy ingots in the melting tank within the copper mold, spacing them at least 5 mm apart. Close the chamber door and evacuate. Evacuate the interior of the vacuum arc melting furnace to 3 × 10⁻⁶ mm. -2 Torr, argon gas is introduced into the cavity of the vacuum arc melting furnace to about 50-60 Torr, then the gas is evacuated. Repeat the above steps 3-4 times, then evacuate the gas pressure to 2 × 10⁻⁶. -2 The pressure is increased to approximately 180 Torr, and argon gas is injected. First, a pure titanium ingot is melted to check for residual oxygen (a yellow surface indicates oxidation). After confirming the ingot is normal, the alloy ingot is melted using a second vacuum arc melting process. This second vacuum arc melting process involves generating an arc with a voltage of 20V and a current of 400A in an argon atmosphere at a chamber pressure of 180 Torr. The edges of the alloy ingot are melted during this process to form a molten metal that bonds with the surrounding alloy ingot, thus forming an aluminum-scandium alloy target blank.

[0048] The aluminum-scandium alloy target blank is cooled at an average cooling rate of about 12°C / min and then taken out from the vacuum arc melting furnace to obtain the aluminum-scandium alloy sputtering target of Example 1.

[0049] Example 2

[0050] Except for using an aluminum ingot and scandium powder with an atomic ratio of 70:30 to form an aluminum-scandium alloy ingot containing 30 at% scandium and 70 at% scandium, and cooling the aluminum-scandium alloy target blank at an average cooling rate of about 10 °C / min, the aluminum-scandium alloy sputtering target of Example 2 was prepared in the same manner as the aluminum-scandium alloy sputtering target of Example 1.

[0051] Example 3

[0052] Except for using aluminum ingots and scandium powder with an atomic ratio of 60:40 to form an aluminum-scandium alloy ingot containing 40 at% scandium and 60 at% scandium, and cooling the aluminum-scandium alloy target blank at an average cooling rate of about 8°C / min, the aluminum-scandium alloy sputtering target of Example 3 was prepared in the same manner as the aluminum-scandium alloy sputtering target of Example 1.

[0053] Comparative Example 1

[0054] Except for cooling the aluminum-scandium alloy target blank at an average cooling rate of about 24°C / min, the aluminum-scandium alloy sputtering target of Comparative Example 1 was prepared in the same manner as the aluminum-scandium alloy sputtering target of Example 1.

[0055] Comparative Example 2

[0056] Except for cooling the aluminum-scandium alloy target blank at an average cooling rate of about 24°C / min, the aluminum-scandium alloy sputtering target of Comparative Example 2 was prepared in the same manner as the aluminum-scandium alloy sputtering target of Example 2.

[0057] Comparative Example 3

[0058] The copper mold is fixed on a water-cooling tank, with water continuously flowing through it to aid heat dissipation. Aluminum ingots with a purity of 4N or higher and scandium powder are placed in the melting tank inside the copper mold at an atomic ratio of 70:30. The chamber door is then closed and a vacuum is created. The interior of the vacuum arc melting furnace is evacuated to 3 × 10⁻⁶ ppm. -2 Torr, argon gas is introduced into the cavity of the vacuum arc melting furnace to about 50-60 Torr, then the gas is evacuated. Repeat the above steps 3-4 times, then evacuate the gas pressure to 2 × 10⁻⁶. -2 The pressure was increased to approximately 180 Torr, and argon gas was injected. Pure titanium ingots were first melted to check for residual oxygen (a yellow surface indicates oxidation). After confirming the titanium ingot was normal, the aluminum ingot and scandium powder were melted using a vacuum arc melting process. The vacuum arc melting process included generating an arc with a voltage of 20V and a current of 400A in an argon atmosphere at a chamber pressure of 180 Torr to melt the formed aluminum-scandium alloy target blank, and then cooling the aluminum-scandium alloy target blank at an average cooling rate of approximately 24°C / min to prepare the aluminum-scandium alloy sputtering target of Comparative Example 3. (That is, Comparative Example 3 directly prepared the aluminum-scandium alloy sputtering target from aluminum ingots and scandium powder, omitting the alloy ingot casting process).

[0059] The process conditions for Examples 1 to 3 are listed in Table 1 below, and the process conditions for Comparative Examples 1 to 3 are listed in Table 2 below.

[0060] Table 1

[0061]

[0062]

[0063] Table 2

[0064] Comparative Example 1 Comparative Example 2 Comparative Example 3 Aluminum (Al) at% 86.4 70 70 Scandium(Sc)at% 13.6 30 30 First vacuum arc melting process O O X First voltage (V) 20 20 -- First current (A) 400 400 -- Cavity pressure (Pa) 180 180 -- Second vacuum arc melting process O O O Second current (V) 20 20 20 Second voltage (A) 400 400 400 Cavity pressure (Pa) 180 180 180 Average cooling rate (°C / min) 24 24 24

[0065] Characteristic Evaluation of Aluminum Scandium Alloy Sputtering Targets

[0066] Visual inspection

[0067] Figure 2A This is a top view schematic diagram of an aluminum-scandium alloy sputtering target according to an embodiment of the present invention. Figure 2B This is a side view of an aluminum-scandium alloy sputtering target according to an embodiment of the present invention. The appearance of the aluminum-scandium alloy sputtering targets of Examples 1 to 3 and Comparative Examples 1 to 3 was observed with the naked eye to check for cracks. The inspection results are shown in Table 3 below, where "X" indicates that no cracks were observed with the naked eye, "Δ" indicates that cracks were observed with the naked eye, and "O" indicates that the aluminum-scandium alloy sputtering target was observed to be broken into several pieces.

[0068] Aluminum scandium grain size measurement

[0069] like Figure 2B As shown, the aluminum-scandium alloy sputtering target according to an embodiment of the present invention includes a front side FS and a back side BS opposite to the front side FS. Figure 2A Sites 1 to 5 (corresponding to the center point, upper edge, lower edge, left edge, and right edge, respectively) were marked, and the aluminum scandium grains at sites 1 to 5 were observed using a field emission electron microscope in backscatter mode. Using the built-in measurement software, one grain was selected from each of the aluminum scandium grains at sites 1 to 5, and the length or width of that grain was measured and defined as the aluminum scandium grain size at site 1 to 5. The aluminum scandium grain sizes at sites 1 to 5 were measured on the front surface (FS) of the aluminum scandium alloy sputtering targets of Examples 1 to 3 and Comparative Examples 1 to 3. The aluminum scandium grain sizes measured at sites 1 to 5 were averaged to obtain the average aluminum scandium grain size of the aluminum scandium alloy sputtering targets of Examples 1 to 3 and Comparative Examples 1 to 3. By comparing the aluminum scandium grain sizes measured at sites 1 to 5, the differences in aluminum scandium grain size (grain uniformity) of the aluminum scandium alloy sputtering targets of Examples 1 to 3 and Comparative Examples 1 to 3 can be obtained. The obtained average aluminum scandium grain size and grain uniformity results are shown in Table 3 below.

[0070] Scandium content measurement

[0071] according to Figure 2A Sites 1-5 were marked, and the aluminum scandium grains at sites 1-5 were observed using a field emission electron microscope in backscatter mode. Then, using an energy-distributed spectrometer at 500x magnification, five randomly selected 40*20 μm regions were subjected to elemental analysis to obtain the scandium content at sites 1-5 on the front (FS) and back (BS) sides of the aluminum scandium alloy sputtering targets of Examples 1-3 and Comparative Examples 1-3. By comparing the scandium contents measured at sites 1-5, the differences in scandium content (compositional uniformity) of the aluminum scandium alloy sputtering targets of Examples 1-3 and Comparative Examples 1-3 could be obtained. The results of the compositional uniformity are shown in Table 3 below.

[0072] Oxygen content measurement

[0073] The oxygen content in the aluminum-scandium alloy sputtering targets of Examples 1 to 3 and Comparative Examples 1 to 3 was measured using an oxygen, nitrogen, and hydrogen analyzer. The oxygen content measurement results are shown in Table 3 below.

[0074] Table 3

[0075]

[0076]

[0077] As shown in Tables 1 to 3, the aluminum-scandium alloy sputtering target prepared at an average cooling rate of 24°C / min exhibits visible cracks, while the aluminum-scandium alloy sputtering target prepared at an average cooling rate less than 24°C / min does not. In other words, the method for preparing the aluminum-scandium alloy sputtering target of this invention can produce crack-free aluminum-scandium alloy sputtering targets. Tables 1 to 3 further show that the aluminum-scandium alloy sputtering target prepared according to the method of this invention has a smaller average aluminum-scandium grain size, better grain uniformity, and better compositional uniformity, and the oxygen content in the aluminum-scandium alloy sputtering target can be less than 100 ppm.

[0078] Example A

[0079] Except for cooling the aluminum-scandium alloy target blank at an average cooling rate of 15°C / min, the aluminum-scandium alloy sputtering target of Example A was prepared in the same manner as the aluminum-scandium alloy sputtering target of Example 2.

[0080] Example B

[0081] Except for cooling the aluminum-scandium alloy target blank at an average cooling rate of 6°C / min, the aluminum-scandium alloy sputtering target of Example B was prepared in the same manner as the aluminum-scandium alloy sputtering target of Example 2.

[0082] The dielectric aluminum-scandium phase of the aluminum-scandium alloy sputtering targets of Examples A and B was analyzed using X-ray diffraction, and compared with the spectra of a standard card. The dielectric aluminum-scandium phase of the aluminum-scandium alloy sputtering targets of Examples A and B was determined, and the results are shown in the figure. Figure 3 as well as Figure 4 . Figure 3 The image shows the XRD pattern of the aluminum-scandium alloy sputtering target of Example A. Figure 4 The image shows the XRD pattern of the aluminum-scandium alloy sputtering target of Example B.

[0083] Depend on Figure 3 as well as Figure 4 It can be seen that the aluminum-scandium alloy sputtering target prepared by the method of the present invention has one or more metallic aluminum-scandium phases including Al3Sc, Al2Sc, or AlSc. Specifically, as shown in the embodiments of the present invention... Figure 3 As shown, the aluminum-scandium alloy sputtering target prepared at an average cooling rate of 15 °C / min has a mesometallic aluminum-scandium phase including Al2Sc and AlSc. Figure 4 As shown, the aluminum-scandium alloy sputtering target prepared at an average cooling rate of 6 °C / min has a monometallic aluminum-scandium phase including Al2Sc and Al3Sc. Therefore, from Figure 3 as well as Figure 4 It can be further seen that aluminum-scandium alloy sputtering targets prepared with different average cooling rates can have different dielectric aluminum-scandium phases.

[0084] In summary, the method for preparing the aluminum-scandium alloy sputtering target of the present invention can obtain a crack-free aluminum-scandium alloy sputtering target by performing two vacuum arc melting processes and adjusting the average cooling rate of the cooled aluminum-scandium alloy target blank. The aluminum-scandium alloy sputtering target can have a smaller average aluminum-scandium grain size, better grain uniformity, and better compositional uniformity.

[0085] While the embodiments and advantages of the present invention have been disclosed above, it should be understood that anyone with common knowledge in the relevant art can make modifications, substitutions, and refinements without departing from the spirit and scope of the invention. Furthermore, the scope of protection of the present invention is not limited to the processes, machines, manufacturing methods, material compositions, apparatuses, methods, and steps described in the specific embodiments of the specification. Anyone with common knowledge in the relevant art can understand, from the disclosure of some embodiments of the present invention, current or future developed processes, machines, manufacturing methods, material compositions, apparatuses, methods, and steps, as long as they can perform substantially the same function or obtain substantially the same results in the embodiments described herein, and can be used according to some embodiments of the present invention. Therefore, the scope of protection of the present invention includes the above-described processes, machines, manufacturing methods, material compositions, apparatuses, methods, and steps. In addition, each claim constitutes an individual embodiment, and the scope of protection of the present invention also includes combinations of the various claims and embodiments.

Claims

1. An aluminum-scandium alloy sputtering target, substantially composed of 10 at% to 50 at% scandium and 90 at% to 50 at% aluminum, comprising: A microstructure comprising an aluminum matrix and a scandium aluminum phase within the aluminum matrix. The scandium phase in the aluminum alloy sputtering target includes Al3Sc, Al2Sc, or AlSc. The scandium content difference between any two different locations on the aluminum-scandium alloy sputtering target is less than or equal to 1 at%, and the scandium grain size difference between any two different locations on one surface of the aluminum-scandium alloy sputtering target is less than or equal to 13 μm.

2. The aluminum-scandium alloy sputtering target according to claim 1, wherein the aluminum-scandium alloy sputtering target is substantially composed of 10 at% to 45 at% scandium and 90 at% to 55 at% aluminum.

3. The aluminum-scandium alloy sputtering target according to claim 1, wherein the average aluminum-scandium grain size of the aluminum-scandium alloy sputtering target is less than 60 μm.

4. The aluminum-scandium alloy sputtering target according to claim 1, wherein the oxygen content of the aluminum-scandium alloy sputtering target is less than or equal to 100 ppm.

5. The aluminum-scandium alloy sputtering target according to claim 4, wherein the oxygen content of the aluminum-scandium alloy sputtering target is less than or equal to 60 ppm.

6. An aluminum-scandium alloy sputtering target, prepared by a method comprising: Pure aluminum and pure scandium with an atomic ratio of 90:10-50:50 are supplied in a melting tank; A first vacuum arc melting process is performed in an inert gas environment to form multiple alloy ingots; Multiple alloy ingots are arranged in a melting tank, wherein the distance between two adjacent alloy ingots is less than or equal to 5 mm. A second vacuum arc melting process is performed in an inert gas environment to melt the plurality of alloy ingots into an aluminum-scandium alloy target blank; and The aluminum-scandium alloy target blank is cooled to form the aluminum-scandium alloy sputtering target, wherein the average cooling rate of the aluminum-scandium alloy target blank is greater than or equal to 5°C / min and less than 24°C / min. The purity of the pure aluminum is greater than or equal to 4N, and the purity of the pure scandium is greater than or equal to 4N.

7. The aluminum-scandium alloy sputtering target according to claim 6, wherein the first vacuum arc melting process includes generating a first arc in the melting tank under an argon atmosphere of 100-250 Torr with a first voltage of 10-30V and a first current of 200-600A, and the second vacuum arc melting process includes generating a second arc in the melting tank under an argon atmosphere of 100-250 Torr with a second voltage of 10-30V and a second current of 200-600A.

8. The aluminum-scandium alloy sputtering target according to claim 6, wherein the average cooling rate of the aluminum-scandium alloy target blank is greater than or equal to 6°C / min and less than or equal to 15°C / min.

9. The aluminum-scandium alloy sputtering target according to claim 6, wherein the average aluminum-scandium grain size of the aluminum-scandium alloy sputtering target is less than 60 μm.

10. A method for preparing an aluminum-scandium alloy sputtering target, comprising: Pure aluminum and pure scandium with an atomic ratio of 90:10-50:50 are provided in a melting tank; In an inert gas environment, a first vacuum arc melting process is performed to form multiple alloy ingots; Multiple alloy ingots are arranged in a melting tank, wherein the distance between two adjacent alloy ingots is less than or equal to 5 mm. In an inert gas environment, a second vacuum arc melting process is performed to melt the plurality of alloy ingots into an aluminum-scandium alloy target blank; and The aluminum-scandium alloy target blank is cooled to form the aluminum-scandium alloy sputtering target, wherein the average cooling rate of the aluminum-scandium alloy target blank is greater than or equal to 5°C / min and less than 24°C / min. The purity of the pure aluminum is greater than or equal to 4N, and the purity of the pure scandium is greater than or equal to 4N.

11. The method for preparing an aluminum-scandium alloy sputtering target according to claim 10, wherein the first vacuum arc melting process includes generating a first arc in the melting tank under an argon atmosphere of 100-250 Torr with a first voltage of 10-30V and a first current of 200-600A; and the second vacuum arc melting process includes generating a second arc in the melting tank under an argon atmosphere of 100-250 Torr with a second voltage of 10-30V and a second current of 200-600A.

12. The method for preparing an aluminum-scandium alloy sputtering target according to claim 10, wherein the average cooling rate of the aluminum-scandium alloy target blank is greater than or equal to 6°C / min and less than or equal to 15°C / min.

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