TWI906041B - Aluminum-scandium alloy target material and manufacturing method thereof - Google Patents

Abstract

A manufacturing method of an aluminum-scandium alloy target material includes the following steps. A first metal mixture and a second metal mixture are respectively subjected to a vacuum melting step and an atomization step to form a first aluminum-scandium alloy powder and a second aluminum-scandium alloy powder, respectively, in which a scandium content of the first aluminum-scandium alloy powder is greater than 35.7 weight percent, and a scandium content of the second aluminum-scandium alloy powder is less than 35.7 weight percent. Then, the first aluminum-scandium alloy powder and the second aluminum-scandium alloy powder are subjected to a dry mixing step and a shaping and densification step to form the aluminum-scandium alloy target material. The aluminum-scandium alloy target material of the present invention has the advantages of high purity, high density, low oxygen content, and good processability.

Description

Aluminum-Gallium Alloy Sputtering Target and its Manufacturing Method

This invention relates to an aluminum-calcium alloy target and its manufacturing method, and particularly to an aluminum-calcium alloy target made using two aluminum-calcium alloy powders with different calcium contents.

Aluminum-calcium alloy sputtering targets are currently mainly used in the sputtering process of aluminum-calcium nitride (ScAlN) piezoelectric films. By adding a small amount of ctanium to the aluminum-calcium nitride piezoelectric film, the frequency response characteristics of the piezoelectric film can be significantly improved. Therefore, aluminum-calcium nitride can be used in high-frequency filters, sensors, microelectromechanical systems (MEMS) microphones, 5G communication semiconductors, automotive electronic components, and consumer electronics products.

Currently, it is known that aluminum-calcium alloy sputtering targets with a calcium content higher than 35.7% by weight (wt.%) can be made using pure aluminum powder and pure calcium powder. However, because pure aluminum powder has a higher oxygen content, the oxygen content of the resulting aluminum-calcium alloy sputtering targets cannot be less than 1000 ppm.

Another known method for manufacturing aluminum-carbide alloy sputtering targets involves using melt casting to produce aluminum-carbide alloy sputtering targets with a carbide content higher than 35.7 wt.%. However, the aluminum-carbide alloy sputtering targets obtained through this process have a traditionally coarse dendritic casting structure, which is detrimental to the uniformity of the film composition formed in subsequent sputtering processes. Furthermore, when the carbide content in the aluminum-carbide alloy sputtering target is greater than 35.7 wt.%, various intermetallic compounds (including _Al3Sc , _Al2Sc , AlSc, and _AlSc2 ) are generated in the alloy. However, these intermetallic compounds cause the alloy to become hard and brittle, which is unfavorable for forging or rolling processes. In other words, it is impossible to improve the microstructure of the target material using processes such as forging or rolling, and the hard and brittle nature of the target material is not conducive to subsequent processing.

Since the coarse dendritic casting structure and oxygen content of aluminum-gallium alloy targets affect the properties of piezoelectric films, there is an urgent need to develop an aluminum-gallium alloy target and its manufacturing method to overcome the above problems.

The manufacturing method of the aluminum-carbide alloy target of this invention combines the advantages of vacuum melting and powder metallurgy. In detail, this invention utilizes a vacuum melting process and atomization process to obtain two types of high-purity, low-oxygen, and homogeneous aluminum-carbide alloy powders, and then uses a powder metallurgy hot pressing process (i.e., forming and densification steps) to obtain a dense aluminum-carbide alloy target.

The aluminum-carbide alloy sputtering material produced by the above manufacturing method has a fine and uniform microstructure, no coarse dendritic casting structure, and low oxygen content. Furthermore, the crystalline phase of the aluminum-carbide alloy sputtering material of the present invention contains metallic aluminum, thus increasing the machinability of the aluminum-carbide alloy sputtering material.

At least one embodiment of the present invention provides a method for manufacturing an aluminum-calcium alloy target, comprising the following steps: providing a first metal mixture and a second metal mixture, wherein the first metal mixture comprises aluminum and calcium, the second metal mixture comprises aluminum and calcium, and the calcium content of the first metal mixture is different from the calcium content of the second metal mixture; and performing a vacuum melting step on the first metal mixture and the second metal mixture respectively to form a first aluminum-calcium alloy block and a second aluminum-calcium alloy block respectively. The first and second aluminum-calcium alloy blocks are respectively atomized to form first and second aluminum-calcium alloy powders. The first aluminum-calcium alloy powder has a carbide content greater than 35.7% by weight (based on the total weight of the first aluminum-calcium alloy powder as 100% by weight), and the second aluminum-calcium alloy powder has a carbide content less than 35.7% by weight (based on the total weight of the second aluminum-calcium alloy powder as 100% by weight). The first and second aluminum-calcium alloy powders are then dry-mixed to form an aluminum-calcium alloy composite powder. Aluminum-carbide alloy composite powder is formed and densified to form an aluminum-carbide alloy target, wherein the crystalline phase of the aluminum-carbide alloy target contains metallic aluminum.

In at least one embodiment of the present invention, the first metal mixture comprises, by weight percentage (100%), greater than 35.7% carbide and the balance being aluminum. The second metal mixture comprises, by weight percentage (100%), less than 35.7% carbide and the balance being aluminum.

In at least one embodiment of the present invention, the first metal mixture and the second metal mixture are respectively formed from an aluminum metal block and a cubic metal block, wherein each of the aluminum metal blocks has a purity of not less than 99.99% and an oxygen content of less than 100 ppm, and each of the cubic metal blocks has a purity of not less than 99.95% and an oxygen content of less than 300 ppm. Each of the vacuum melting steps is a vacuum arc melting process or a vacuum suspension melting process, and the vacuum degree of each of the vacuum melting steps is not greater than ^10⁻³ Torr.

In at least one embodiment of the present invention, the atomization step further includes the following steps: Processing the first aluminum-calcium alloy block and the second aluminum-calcium alloy block respectively to form a first aluminum-calcium alloy electrode rod and a second aluminum-calcium alloy electrode rod. Induction heating of the first aluminum-calcium alloy electrode rod and the second aluminum-calcium alloy electrode rod in a vacuum environment to form a first aluminum-calcium alloy solution and a second aluminum-calcium alloy solution respectively, wherein the gas source for each of these atomization steps is argon. Atomization of the first aluminum-calcium alloy solution and the second aluminum-calcium alloy solution is performed using argon.

In at least one embodiment of the present invention, the vacuum degree of the vacuum environment is not greater than ^10⁻³ Torr, the purity of argon is not less than 99.999%, and the atomization pressure of the atomization step is 20 atm to 35 atm.

In at least one embodiment of the present invention, the carbide content of the aluminum-carbide alloy composite powder satisfies the following formula (I): Formula (I) With the total weight of the aluminum-calcium alloy composite powder as 100% by weight, G_{_t} represents the carbide content of the aluminum-calcium alloy composite powder. _W₁ represents the weight percentage of the first aluminum-calcium alloy powder, and with the total weight of the first aluminum-calcium alloy powder as 100% by weight, G _₁ represents the carbide content of the first aluminum-calcium alloy powder. W _₂ represents the weight percentage of the second aluminum-calcium alloy powder, and with the total weight of the second aluminum-calcium alloy powder as 100% by weight, G_₂ represents the carbide content of the second aluminum-calcium alloy powder, and W_₁ + W _₂ = 100% by weight.

In at least one embodiment of the present invention, the carbide content of the aluminum-carbide alloy composite powder is not less than 35.7% by weight, based on the total weight of the aluminum-carbide alloy composite powder as 100% by weight.

In at least one embodiment of the present invention, the mixing time of the dry mixing step is 2 hours to 12 hours, wherein the molding and densification step is a hot pressing molding process of resistance heating or a hot pressing molding process of direct heating.

In at least one embodiment of the present invention, the heating temperature of the molding and densification step is not greater than the solidus temperature of the first aluminum-calcium alloy powder and the second aluminum-calcium alloy powder, the hot pressing pressure in the molding and densification step is 10 MPa to 55 MPa, and the hot pressing time in the molding and densification step is 30 minutes to 6 hours.

At least one embodiment of the present invention provides an aluminum-calcium alloy sputtering target, manufactured by the above-described method for manufacturing aluminum-calcium alloy sputtering targets. The aluminum-calcium alloy sputtering target comprises 35.7 to 70% by weight of ctanium and the balance being aluminum. The purity of the aluminum-calcium alloy sputtering target is not less than 99.95%, the density of the aluminum-calcium alloy sputtering target is not less than 99.6%, and the oxygen content of the aluminum-calcium alloy sputtering target is less than 1000 ppm.

The manufacture and use of embodiments of the present invention will now be discussed in detail. However, it is understood that the embodiments provide many applicable inventive concepts that can be implemented in a wide variety of specific contexts. The specific embodiments discussed are for illustrative purposes only and are not intended to limit the scope of the present invention.

In this document, the range referred to as "from one value to another" is a summary representation that avoids listing all the values within that range in the specification. Therefore, the description of a particular range of values encompasses any value within that range as well as the smaller range of values defined by that value, just as if the arbitrary value and the smaller range of values were explicitly stated in the specification.

Understandably, while terms such as "first" and "second" may be used to describe various features, these features should not be limited by these terms. These terms are only used to distinguish one feature from another. For example, without departing from the scope of implementation, a first feature can be called a second feature, and similarly, a second feature can be called a first feature.

Please refer to Figure 1, which is a schematic flowchart of a method 100 for manufacturing an aluminum-calcium alloy target according to some embodiments of the present invention. As shown in step 110 of Figure 1, a first metal mixture and a second metal mixture are provided. The first metal mixture contains aluminum and calcium, and the second metal mixture contains aluminum and calcium, wherein the calcium content of the first metal mixture is different from the calcium content of the second metal mixture. In an embodiment of step 110, the first metal mixture and the second metal mixture are formed from an aluminum metal block and a calcium metal block, respectively.

Understandably, the amounts of aluminum and carbide metal blocks used depend on the desired ratio of the aluminum-carbide metal mixture (i.e., the first metal mixture and the second metal mixture). In some embodiments, the first metal mixture contains more than 35.7% carbide and the balance aluminum, based on 100% of the total weight of the first metal mixture. In other words, the first metal mixture contains less than 64.3% carbide. In some embodiments, the second metal mixture contains less than 35.7% carbide and the balance aluminum, based on 100% of the total weight of the second metal mixture. In other words, the second metal mixture contains more than 64.3% carbide.

In some embodiments, the purity of each of these aluminum metal blocks may selectively be not less than 99.99%, and the purity of each of these titanium metal blocks may selectively be not less than 99.95%, but is not limited thereto. When the purity of the aforementioned aluminum and titanium metal blocks is within the above range, it is beneficial to improve the purity of the subsequently obtained aluminum-titanium alloy sputtering target.

In some embodiments, the oxygen content of each of these aluminum metal blocks may selectively be less than 100 ppm, and the oxygen content of each of these carbide metal blocks may selectively be less than 300 ppm, but is not limited thereto. When the oxygen content of the aforementioned aluminum and carbide metal blocks is within the above range, it is advantageous to reduce the oxygen content of the subsequently obtained aluminum-carbide alloy target.

Then, as shown in step 120 of Figure 1, the first metal mixture and the second metal mixture are subjected to a vacuum melting step to form a first aluminum-carbide alloy ingot and a second aluminum-carbide alloy ingot, respectively. In some embodiments, the vacuum melting step is performed using a water-cooled copper crucible or without a crucible.

In some embodiments, each of the above-described vacuum melting steps can be a vacuum arc melting process or a vacuum levitation melting process. Generally, the vacuum arc melting process is carried out using a water-cooled copper crucible, thus reducing the reactivity between the metal block and the crucible. Conversely, the vacuum levitation melting process does not require the use of a crucible, thus eliminating impurities generated by the reaction between the crucible and the metal block. In some embodiments, the vacuum level in each of the above-described vacuum melting steps can selectively be no greater than ^10⁻³ Torr, but is not limited to this. When the vacuum level in the vacuum melting step is no greater than ^10⁻³ Torr, it is advantageous to reduce the oxygen content of the subsequently obtained aluminum-calcium alloy target.

In some embodiments, the vacuum level of the aforementioned vacuum environment may selectively be no more than ^10⁻³ Torr, but is not limited thereto. When the vacuum level in the induction heating step is no more than ^10⁻³ Torr, it is advantageous to reduce the oxygen content of the subsequently obtained aluminum-copper alloy target.

Next, as shown in step 130 of Figure 1, the first aluminum-calcium alloy block and the second aluminum-calcium alloy block are respectively subjected to atomization to form first aluminum-calcium alloy powder and second aluminum-calcium alloy powder, respectively. In step 130, the first aluminum-calcium alloy block and the second aluminum-calcium alloy block are respectively processed to form first aluminum-calcium alloy electrode rod and second aluminum-calcium alloy electrode rod, respectively. Subsequently, under a vacuum environment, the first aluminum-calcium alloy electrode rod and the second aluminum-calcium alloy electrode rod are respectively subjected to induction heating to form first aluminum-calcium alloy solution and second aluminum-calcium alloy solution, respectively. In some embodiments, the gas source for each of these atomization steps is argon. Specifically, the atomization step refers to the process of atomizing the first and second aluminum-calcium alloy solutions into first and second aluminum-calcium alloy powders respectively using high-purity argon gas at the instant the first and second aluminum-calcium alloy solutions are formed. It is understood that the first and second aluminum-calcium alloy powders are made from a first metal mixture and a first metal mixture. Therefore, based on the total weight of the first aluminum-calcium alloy powder as 100% by weight, the carbide content of the first aluminum-calcium alloy powder is greater than 35.7% by weight, and based on the total weight of the second aluminum-calcium alloy powder as 100% by weight, the carbide content of the second aluminum-calcium alloy powder is less than 35.7% by weight.

In some embodiments, the purity of argon is not less than 99.999%. In some embodiments, the atomization pressure of the atomization step (i.e., the atomization pressure of argon) can selectively be from 20 atm to 35 atm, for example, 22 atm, 25 atm, 28 atm, 30 atm, or 32 atm, but is not limited thereto. When the atomization pressure is less than 20 atm, the alloy solution cannot be sufficiently atomized, resulting in some powder particles not being evenly dispersed and sticking together, which is not conducive to the formation of the aluminum-carbide alloy target of the present invention. When the atomization pressure is greater than 35 atm, over-atomization occurs, resulting in powder particles that are too small and have too high an oxygen content, which is also not conducive to the formation of the aluminum-carbide alloy target of the present invention. In other words, when the atomization pressure is within the above range, a better atomization effect can be achieved, which is beneficial for obtaining aluminum-calcium alloy sputtering materials with good processability and an oxygen content of less than 1000 ppm.

It is understandable that both the first aluminum-calcium alloy powder and the second aluminum-calcium alloy powder in this case are pre-alloyed powders. Since the pre-alloyed powder has already reached an alloyed state during the manufacturing process, each powder particle contains a pre-defined alloy composition. Compared to traditional aluminum-calcium alloy targets made from pure aluminum powder and pure carbide powder, the aluminum-calcium alloy target of this invention utilizes two pre-alloyed powders with different carbide contents (i.e., a first aluminum-calcium alloy powder with a carbide content greater than 35.7% by weight and a second aluminum-calcium alloy powder with a carbide content less than 35.7% by weight). Therefore, it does not have the problem of higher oxygen content in pure aluminum powder as in traditional methods. As a result, the aluminum-calcium alloy target produced by this invention has an oxygen content of less than 1000 ppm.

Then, as shown in step 140 of Figure 1, a dry mixing step is performed on the first aluminum-calcium alloy powder and the second aluminum-calcium alloy powder to form an aluminum-calcium alloy composite powder. In some embodiments, the dry mixing step is performed in an atmospheric environment or a nitrogen environment.

During the dry mixing step, based on the desired carbide content of the aluminum-carbide alloy target material to be produced, a first aluminum-carbide alloy powder with a specific carbide content and its weight, and a second aluminum-carbide alloy powder with a specific carbide content and its weight, are selected and adjusted. The carbide content of the aluminum-carbide alloy composite powder satisfies the following formula (I): Formula (I) With the total weight of the aluminum-calcium alloy composite powder as 100% by weight, G_{_t} represents the carbide content of the aluminum-calcium alloy composite powder. W _₁ represents the weight percentage of the first aluminum-calcium alloy powder. With the total weight of the first aluminum-calcium alloy powder as 100% by weight, G _₁ represents the carbide content of the first aluminum-calcium alloy powder. W _₂ represents the weight percentage of the second aluminum-calcium alloy powder. With the total weight of the second aluminum-calcium alloy powder as 100% by weight, G _₂ represents the carbide content of the second aluminum-calcium alloy powder, and W_₁ + W _₂ = 100% by weight.

In some embodiments, the carbide content of the aluminum-carbide alloy composite powder is not less than 35.7% by weight, for example, 35.7% to 70% by weight or 42% to 55% by weight, based on 100% by weight of the total weight of the aluminum-carbide alloy composite powder.

In some embodiments, the mixing time of the dry mixing step can be selectively between 2 hours and 12 hours, but is not limited to this. When the mixing time is less than 2 hours, the first aluminum-calcium alloy powder and the second aluminum-calcium alloy powder may not be mixed uniformly. When the mixing time is greater than 12 hours, it is not cost-effective. Therefore, when the mixing time is within the above range, it is advantageous to form the aluminum-calcium alloy target of this invention.

Then, as shown in step 150 of Figure 1, the aluminum-carbide alloy composite powder is subjected to molding and densification steps to form an aluminum-carbide alloy target. In some embodiments, the molding and densification steps are resistance heating hot pressing processes or direct heating hot pressing processes.

In some embodiments, the heating temperature of the forming and densification step (i.e., resistance heating hot pressing or direct heating hot pressing) is not greater than the solidus temperatures of the first and second aluminum-calcium alloy powders. In some embodiments, it is assumed that the solidus temperature of the first aluminum-calcium alloy powder is T1 and the solidus temperature of the second aluminum-calcium alloy powder is T2, where T1 > T2. The heating temperature in the forming and densification step is taken as more than 70% of the lower solidus temperature (i.e., T2). If the heating temperature is lower than 70% of the lower solidus temperature (i.e., T2), the density of the formed aluminum-calcium alloy target is poor, which is detrimental to the formation of the aluminum-calcium alloy target of this invention.

In some embodiments, the hot pressing pressure in the forming and densification steps can selectively be from 10 MPa to 55 MPa, such as 20 MPa, 30 MPa, 40 MPa, or 50 MPa, but is not limited thereto. When the hot pressing pressure is less than 10 MPa, the densification of the formed aluminum-gallium alloy sputtering material is poor, which is not conducive to the formation of the aluminum-gallium alloy sputtering material of the present invention. Due to the limitation of the mold pressure, the hot pressing pressure is at most 55 MPa, and when the hot pressing pressure is greater than 55 MPa, there is no particular benefit to the formed aluminum-gallium alloy sputtering material.

In some embodiments, the hot pressing time in the forming and densification steps can be selectively set from 30 minutes to 6 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, or 5 hours. When the hot pressing time is less than 30 minutes, the diffusion time is insufficient, which is not conducive to the formation of the aluminum-calcium alloy sputtering material of this invention. When the hot pressing time is greater than 6 hours, the resulting aluminum-calcium alloy sputtering material has coarse grains, which is not in line with the process cost.

In some embodiments, the forming and densification steps utilize molds of specific shapes to produce aluminum-gallium alloy sputtering targets with specific shapes, thus eliminating the need for removing head, tail, and edge materials. Therefore, compared to traditional casting processes, the yield of aluminum-gallium alloy sputtering targets produced using the method of this invention is higher (e.g., higher than 95%).

This invention provides an aluminum-calcium alloy sputtering target, manufactured by the aforementioned method 100. In some embodiments, the aluminum-calcium alloy sputtering target comprises 35.7% to 70% by weight of ctanium and the balance being aluminum. In some embodiments, the ctanium content of the aluminum-calcium alloy sputtering target is, for example, 42% to 55% by weight. In some embodiments, the purity of the aluminum-calcium alloy sputtering target is not less than 99.95%, the density of the aluminum-calcium alloy sputtering target is not less than 99.6%, and the oxygen content of the aluminum-calcium alloy sputtering target is less than 1000 ppm.

In some embodiments, the crystalline phase of the aluminum-calcium alloy sputtering target comprises metallic aluminum. In one specific embodiment, the crystalline phase of the aluminum-calcium alloy sputtering target comprises metallic aluminum, _Al3Sc , _Al2Sc , and AlSc. In another specific embodiment, the crystalline phase of the aluminum-calcium alloy sputtering target comprises metallic aluminum, _Al3Sc , _Al2Sc , AlSc, and _AlSc2 . It is worth noting that, since the crystalline phase of the aluminum-calcium alloy sputtering target of the present invention comprises metallic aluminum, the problem of conventional targets becoming hard and brittle due to intermetallic compounds (including _Al3Sc , _Al2Sc , AlSc, and _AlSc2 ) can be improved, thus the aluminum-calcium alloy sputtering target of the present invention is advantageous for subsequent processing.

It should be noted that the first aluminum-calcium alloy powder with a carbide content greater than 35.7% by weight provides brittleness to the aluminum-calcium alloy sputtering material, while the second aluminum-calcium alloy powder with a carbide content less than 35.7% by weight provides toughness. Therefore, the resulting aluminum-calcium alloy sputtering material has a certain degree of toughness and is not too hard and brittle, which is beneficial for subsequent processing.

Based on the above, the manufacturing method of the aluminum-calcium alloy target of the present invention utilizes two types of high-purity, low-oxygen, and homogeneous aluminum-calcium alloy powders (i.e., a first aluminum-calcium alloy powder and a second aluminum-calcium alloy powder). The carbide content and weight of the aluminum-calcium alloy powders are selected and adjusted using the above formula (I) to obtain an aluminum-calcium alloy composite powder with a carbide content of not less than 35.7% by weight. Then, molding and densification steps are performed to form an aluminum-calcium alloy target with a carbide content of 35.7% to 70% by weight. The aluminum-calcium alloy target of the present invention has advantages such as high purity, high density, low oxygen content, and good processability. The aluminum-carbide sputtering target of this invention can be used in the sputtering process of ScAlN piezoelectric thin films in the communications industry, but is not limited thereto.

The following experimental and comparative examples illustrate the application of the invention, but they are not intended to limit the invention. Anyone skilled in this art may make various modifications and refinements without departing from the spirit and scope of the invention.

Experimental Example 1

Example 1 uses a 58wt.% aluminum-42wt.% carbide alloy target as the manufacturing target. First, a first metal mixture and a second metal mixture are provided. The first metal mixture contains 25wt.% aluminum and 75wt.% carbide, and the second metal mixture contains 95wt.% aluminum and 5wt.% carbide. The aluminum ingot has a purity greater than 99.999% and an oxygen content less than 20ppm. The carbide ingot has a purity greater than 99.95% and an oxygen content less than 300ppm.

Next, the first metal mixture and the second metal mixture are subjected to vacuum arc melting processes to form a first aluminum-calcium alloy block and a second aluminum-calcium alloy block, respectively, wherein the vacuum degree of the vacuum arc melting process is not greater than ^10⁻³ Torr.

Then, a misting step is performed, in which the first and second aluminum-calcium alloy blocks are processed to form first and second aluminum-calcium alloy electrode rods, respectively. Next, the first and second aluminum-calcium alloy electrode rods are placed in the induction coil of a vacuum induction heating furnace to perform induction heating, forming first and second aluminum-calcium alloy solutions, respectively. The vacuum level during the induction heating step is less than or equal to ^10⁻³ Torr. Finally, the first and second aluminum-calcium alloy solutions are introduced into the misting chamber, respectively. At the instant the first aluminum-calcium alloy solution and the second aluminum-calcium alloy solution enter the atomization chamber, they are respectively atomized into first aluminum-calcium alloy powder and second aluminum-calcium alloy powder by high-pressure argon gas at 35 atm (atomization pressure). The purity of the high-pressure argon gas is greater than 99.999%.

Subsequently, the first aluminum-calcium alloy powder and the second aluminum-calcium alloy powder were subjected to a dry mixing process. Using the formula (I) above, 52.9 wt.% of the first aluminum-calcium alloy powder (containing 75 wt.% of carbide and the remainder of aluminum) and 47.1 wt.% of the second aluminum-calcium alloy powder (containing 5 wt.% of carbide and the remainder of aluminum) were mixed for 8 hours to obtain the aluminum-calcium alloy composite powder of Experimental Example 1, with a composition of 58 wt.% aluminum and 42 wt.% carbide. The parameters in formula (I) are shown in Table 1 below.

Then, the aluminum-carbide alloy composite powder is formed and densified. 58 wt.% aluminum-42 wt.% aluminum-carbide alloy composite powder is placed in a graphite mold, and a direct-heating hot-press forming process is used to apply current to the composite powder. The powder is heated by the resistance heat generated by the current flowing through it, raising the temperature to 820°C and holding it at that temperature for 45 minutes. Simultaneously, a hot-press forming pressure of 15 MPa is applied to the composite powder to obtain the aluminum-carbide alloy target of Example 1, which has a composition of 58 wt.% aluminum-42 wt.% carbide. The aluminum-carbide alloy target of Example 1 has a relative density of 99.8%, a purity of 99.97%, and an oxygen content of 360 ppm. The crystalline phases of the aluminum-carbide alloy sputtering target of Example 1 include metallic aluminum, _Al3Sc , _Al2Sc , AlSc, and _AlSc2 . The characteristics of the aluminum-carbide alloy sputtering target of Example 1 are shown in Table 2 below.

Table 1 Experimental Example 1 Experimental Example 2 58wt.% aluminum-42wt.% gluconium alloy sputtering target 45wt.% aluminum-55wt.% carbide alloy sputtering target W ₁ 52.9 90 G ₁ 75 60 W ₂ 47.1 10 _G2 5 10 G _t 42 55

Table 2 Experimental Example 1 Experimental Example 2 58wt.% aluminum-42wt.% gluconium alloy sputtering target 45wt.% aluminum-55wt.% carbide alloy sputtering target relative density 99.8% 99.60% Purity 99.97% 99.95% Oxygen content 360ppm 430ppm crystalline phase Metallic aluminum, _Al3Sc , _Al2Sc , AlSc and _AlSc2 Metallic aluminum, _Al3Sc , _Al2Sc and AlSc

Experimental Example 2

Experiment 2 was conducted in a similar manner to Experiment 1. The difference is that Experiment 2 used a 45wt.% aluminum-55wt.% carbide alloy target. The differences between Experiment 1 and Experiment 2 will be explained below, and the similarities will not be repeated.

In Experiment 2, the first metal mixture contained 40 wt.% aluminum and 60 wt.% carbide, and the second metal mixture contained 90 wt.% aluminum and 10 wt.% carbide. The aluminum ingots had a purity greater than 99.99% and an oxygen content less than 100 ppm. The carbide ingots had a purity greater than 99.95% and an oxygen content less than 300 ppm. The vacuum melting step in Experiment 2 employed a vacuum suspension melting process. The atomization step in Experiment 2 involved spraying the first and second aluminum-carbide alloy solutions with high-pressure argon gas at 25 atm (atomization pressure).

In Experimental Example 2, by calculating using the above formula (I), 90 wt.% of the first aluminum-calcium alloy powder (containing 60 wt.% of carbide and the remainder of aluminum) and 10 wt.% of the second aluminum-calcium alloy powder (containing 10 wt.% of carbide and the remainder of aluminum) were mixed for 4 hours to obtain the aluminum-calcium alloy composite powder of Experimental Example 2, with a composition of 45 wt.% aluminum and 55 wt.% carbide. The parameters in formula (I) of Experimental Example 2 are shown in Table 1 above.

In the molding and densification steps of Example 2, the temperature of the composite powder was set to 1000°C and held for 4 hours. Simultaneously, a hot pressing pressure of 50 MPa was applied to the composite powder to obtain the aluminum-carbide alloy sputtering target of Example 2, with a composition of 45 wt.% aluminum and 55 wt.% carbide. The aluminum-carbide alloy sputtering target of Example 2 has a relative density of 99.6%, a purity of 99.95%, and an oxygen content of 430 ppm. The crystalline phases of the aluminum-carbide alloy sputtering target of Example 2 include metallic aluminum, _Al3Sc , _Al2Sc , and AlSc. The characteristics of the aluminum-carbide alloy sputtering target of Example 2 are shown in Table 2 above.

It is understood that although the present invention uses specific composition, specific manufacturing method and specific evaluation method as examples to illustrate the aluminum-calcium alloy target material and its manufacturing method, it is clear to anyone with ordinary knowledge in the art to which the present invention pertains that the present invention is not limited thereto. Other compositions, other manufacturing methods or other evaluation methods may also be used without departing from the spirit and scope of the present invention.

Please refer to Figure 2, which is a scanning electron microscope image 200 of the aluminum-carbide alloy target material according to Experimental Example 2 of the present invention. As can be seen from Figure 2, the microstructure of the aluminum-carbide alloy target material is uniformly distributed and there is no coarse dendritic casting structure.

The method for manufacturing aluminum-calcium alloy sputtering targets provided by this invention combines the advantages of powder metallurgy and vacuum melting processes, and can produce aluminum-calcium alloy sputtering targets with a carbide content greater than 35.7 wt.% and an oxygen content less than 1000 ppm. The resulting sputtering targets have a fine and uniform microstructure, without coarse dendritic casting structures, and possess a crystalline phase of metallic aluminum, thus facilitating subsequent processing.

Although the present invention has been disclosed above by way of implementation, it is not intended to limit the present invention. Anyone with ordinary knowledge in the art to which the present invention pertains may make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended patent application.

100: Method 110, 120, 130, 140, 150: Steps 200: Scanning electron microscope images

To make the above and other objects, features, advantages, and embodiments of the present invention more apparent, detailed descriptions of the accompanying drawings are provided below. Figure 1 is a schematic flowchart of a method for manufacturing an aluminum-calcium alloy target according to some embodiments of the present invention. Figure 2 is a scanning electron microscope image of the aluminum-calcium alloy target according to Experimental Example 2 of the present invention.

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100: Method

110, 120, 130, 140, 150: Steps

Claims (10)

A method for manufacturing an aluminum-calcium alloy target includes: providing a first metal mixture and a second metal mixture, wherein the first metal mixture comprises aluminum and carbide, the second metal mixture comprises aluminum and carbide, and the carbide content of the first metal mixture is different from the carbide content of the second metal mixture; and performing a vacuum melting step on the first metal mixture and the second metal mixture respectively to form a first aluminum-calcium alloy block and a second aluminum-calcium alloy block respectively; The first aluminum-calcium alloy block and the second aluminum-calcium alloy block are respectively subjected to a misting step to form a first aluminum-calcium alloy powder and a second aluminum-calcium alloy powder, wherein, based on the total weight of the first aluminum-calcium alloy powder as 100% by weight, the carbide content of the first aluminum-calcium alloy powder is greater than 35.7% by weight, and based on the total weight of the second aluminum-calcium alloy powder as 100% by weight, the carbide content of the second aluminum-calcium alloy powder is less than 35.7% by weight; the first aluminum-calcium alloy powder and the second aluminum-calcium alloy powder are then subjected to a dry mixing step to form an aluminum-calcium alloy composite powder; and The aluminum-calcium alloy composite powder is subjected to a molding and densification step to form the aluminum-calcium alloy target, wherein the crystalline phase of the aluminum-calcium alloy target includes metallic aluminum, and the aluminum-calcium alloy target contains 42 to 70 wt% of carbide and the balance of aluminum. The method for manufacturing an aluminum-calcium alloy target as described in claim 1, wherein the first metal mixture comprises, based on 100% by weight, greater than 35.7% by weight of ctanium and the balance of aluminum, and wherein, based on 100% by weight of the second metal mixture, the second metal mixture comprises less than 35.7% by weight of ctanium and the balance of aluminum. The method for manufacturing an aluminum-calcium alloy target as described in claim 1, wherein the first metal mixture and the second metal mixture are respectively formed from an aluminum metal block and a calcium metal block, wherein the purity of each of the aluminum metal blocks is not less than 99.99%, the oxygen content of each of the aluminum metal blocks is less than 100 ppm, the purity of each of the calcium metal blocks is not less than 99.95%, and the oxygen content of each of the calcium metal blocks is less than 300 ppm, wherein each of the vacuum melting steps is a vacuum arc melting process or a vacuum suspension melting process, and the vacuum degree of each of the vacuum melting steps is not greater than ^10⁻³ Torr. The method for manufacturing an aluminum-calcium alloy target as described in claim 1, wherein the atomization step further comprises: performing a processing step on the first aluminum-calcium alloy block and the second aluminum-calcium alloy block respectively to form a first aluminum-calcium alloy electrode rod and a second aluminum-calcium alloy electrode rod respectively; performing an induction heating step on the first aluminum-calcium alloy electrode rod and the second aluminum-calcium alloy electrode rod respectively in a vacuum environment to form a first aluminum-calcium alloy solution and a second aluminum-calcium alloy solution respectively; and performing the atomization step on the first aluminum-calcium alloy solution and the second aluminum-calcium alloy solution respectively using argon gas. The method for manufacturing an aluminum-gallium alloy target as described in claim 4, wherein the vacuum degree of the vacuum environment is not greater than ^10⁻³ Torr, the purity of the argon gas is not less than 99.999%, and the atomization pressure of the atomization step is 20 atm to 35 atm. The method for manufacturing an aluminum-carbide alloy target as described in claim 1, wherein the carbide content of the aluminum-carbide alloy composite powder satisfies the following formula (I): Formula (I) Wherein, with the total weight of the aluminum-calcium alloy composite powder as 100% by weight, G_{_t} represents the carbine content of the aluminum-calcium alloy composite powder, where W_₁ represents the weight percentage of the first aluminum-calcium alloy powder, and with the total weight of the first aluminum-calcium alloy powder as 100% by weight, G_₁ represents the carbine content of the first aluminum-calcium alloy powder, where W_₂ represents the weight percentage of the second aluminum-calcium alloy powder, and with the total weight of the second aluminum-calcium alloy powder as 100% by weight, G_₂ represents the carbine content of the second aluminum-calcium alloy powder, and W_₁ + W_₂ = 100% by weight. The method for manufacturing an aluminum-calcium alloy target as described in claim 1, wherein the carbide content of the aluminum-calcium alloy composite powder is not less than 35.7% by weight, based on 100% by weight of the total weight of the aluminum-calcium alloy composite powder. The method for manufacturing aluminum-calcium alloy target material as described in claim 1, wherein the mixing time of the dry powder mixing step is 2 hours to 12 hours, and wherein the molding and densification step is a resistance heating hot pressing molding process or a direct heating hot pressing molding process. The method for manufacturing an aluminum-calcium alloy target as described in claim 1, wherein the heating temperature in the forming and densification step is not greater than the solidus temperature of the first aluminum-calcium alloy powder and the second aluminum-calcium alloy powder, the hot pressing pressure in the forming and densification step is 10 MPa to 55 MPa, and the hot pressing time in the forming and densification step is 30 minutes to 6 hours. An aluminum-calcium alloy sputtering target is manufactured by a method for manufacturing an aluminum-calcium alloy sputtering target as described in any one of claims 1 to 9, wherein the aluminum-calcium alloy sputtering target comprises 42 to 70% by weight of calcium and the balance being aluminum, wherein the purity of the aluminum-calcium alloy sputtering target is not less than 99.95%, the density of the aluminum-calcium alloy sputtering target is not less than 99.6%, and the oxygen content of the aluminum-calcium alloy sputtering target is less than 1000 ppm.