Electron beam welding method for ultra-pure aluminum target material and aluminum alloy back plate

Abstract

According to the electron beam welding method for the ultra-pure aluminum target material and the aluminum alloy back plate, the characteristics that Al, Si, Cu and stable metal elements in the welding piece are low in melting point and high in fluidity are utilized, metal at the position of a welding seam can be rapidly melted, the welding seam is fully filled, and therefore the defects such as air holes and cracks are reduced, and the welding quality is improved. And meanwhile, the formed second-phase particles are used for improving the welding strength of a welding seam, and finally the ultra-pure aluminum target assembly with the good welding joint performance and the defect-free appearance is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of sputtering target materials, and in particular to an electron beam welding method for an ultra-high purity aluminum target material and an aluminum alloy back plate. Background Art

[0002] Conventional welding methods for target materials and backing plates include diffusion welding, brazing, electron beam welding, argon arc welding, etc. Among them, electron beam welding uses a high-energy electron beam to bombard the surface of the weld of the material to be welded, generating huge heat to melt one or more metals to be welded at the weld, thereby achieving the purpose of welding.

[0003] As one of the key materials in the field of semiconductor manufacturing, ultra-high purity aluminum targets play a vital role in the interconnection process of integrated circuits. Currently, vacuum electron beam welding is commonly used in industrial production to weld ultra-high purity aluminum targets to aluminum alloy backplanes. Although vacuum electron beam welding has the advantages of simple welding, wide adjustable range of welding process parameters, strong applicability, and low welding cost, it is very easy to produce defects such as pores and cracks during electron beam welding of ultra-high purity aluminum targets to aluminum alloy backplanes. In addition, due to the influence of aluminum oxide layer, H atoms and various alloying elements during electron beam welding, the weld quality is poor and the welding strength is low, which is not conducive to the high-quality production and use of ultra-high purity aluminum targets, and restricts its development towards more advanced processes.

[0004] Target sputtering is typically performed in the harsh, high-voltage, high-vacuum environment of a sputtering machine. Ultra-high-purity aluminum (UHPA) is inherently weak. Poor weld quality and low weld strength between the target and backing plate can lead to target deformation and cracking during sputtering, preventing ideal sputtering results. There's even a risk of the target falling off the backing plate, damaging the sputtering equipment. Therefore, as a mainstream product in the semiconductor target industry, UHPA targets place high demands on weld appearance, weld strength, and weld quality.

[0005] Existing ultra-high-purity aluminum target electron beam welding, because ultra-high-purity aluminum and aluminum alloys are typically subjected to various measures during the smelting stage to ensure the ingot is formed, absorbed hydrogen is usually retained in the ingot as hydrogen atoms. Therefore, during electron beam welding, at high temperatures, hydrogen atoms in the matrix of the material to be welded are precipitated to form hydrogen gas, which escapes into the molten pool. When the molten pool rapidly cools and solidifies, the hydrogen gas fails to escape in time and remains in the molten pool, forming pores. In addition, the molten pool cools and solidifies too quickly, which can easily lead to cracking between the dendrites of the molten pool, forming thermal cracks. It can also cause uneven distribution of alloying elements in the molten pool, forming brittle phases and reducing weld strength. Existing processes for ultra-high-purity aluminum target electron beam welding are unstable and easily cause welding discharge, resulting in batch product scrapping, increasing production costs, reducing production efficiency, and being unfavorable for large-scale industrial production.

[0006] Currently, the commonly used methods for improving defects in electron beam welding of high-purity aluminum targets in the industry are mainly through repeated electron beam welding and scanning electron beam welding. Repeated electron beam welding refers to repeated welding on the same weld. Its advantage is that it increases the holding time of the weld pool, allowing gases to escape easily, thereby reducing porosity. However, its disadvantages are that repeated welding can lead to burnout of alloying elements. At the same time, the temperature of the heat-affected zone of the target material increases significantly after repeated welding, causing deformation of the target material, which is not conducive to subsequent processing. Moreover, after repeated welding, the porosity reduction will become very slow. Scanning electron beam welding refers to the electron beam moving left and right in the direction perpendicular to the weld while moving along the weld. The movement frequency is generally between 100-10,000 Hz. Its advantage is that the left and right movement of the electron beam mechanically stirs the molten pool, allowing gases in the molten pool to escape easily. However, its disadvantage is that scanning welding has a limited effect on reducing porosity and cannot fundamentally solve the problem of porosity reduction.

[0007] CN114029599A discloses an electron beam welding structure and a welding method thereof, the welding method comprising the following steps: providing an aluminum alloy part to be welded at the welding point between the back plate and the target, melting the part to be welded by an electron beam, wherein the part to be welded has good fluidity during the electron beam welding process, and the melted part to be welded can quickly flow to fill the welding point between the target and the back plate, connecting the two together, and achieving welding after cooling. The use of the aluminum alloy part to be welded helps to reduce the generation of thermal cracks, and its good fluidity makes the welding deformation of the parent material very small, reducing the possibility of cracks or porosity defects in electron beam welding without increasing the number of welds. However, the composition of the part to be welded is closely related to the composition of the target and the back plate. The technical solution is aimed at electron beam welding of an aluminum-silicon alloy target and an aluminum alloy back plate, and uses an aluminum alloy material with a grade of A4047 as the part to be welded. However, it does not provide what material the part to be welded should be used for electron beam welding of an ultra-high purity aluminum target and an aluminum alloy back plate.

[0008] In summary, it is necessary to develop an electron beam welding method for ultra-high purity aluminum target and aluminum alloy back plate, focusing on the development of materials for the welded parts corresponding to the electron beam welding. Summary of the Invention

[0009] In view of the problems existing in the prior art, the present invention provides an electron beam welding method for an ultra-high purity aluminum target and an aluminum alloy back plate. The method utilizes the low melting point and high fluidity of Al, Si, Cu and stable metal elements in the welding sheet to enable the metal at the weld position to melt quickly and fully fill the weld, thereby reducing the generation of defects such as pores and cracks. At the same time, the formed second phase particles are utilized to improve the welding strength of the weld, and finally an ultra-high purity aluminum target assembly with good welding joint performance and no defects in appearance is obtained.

[0010] To achieve this object, the present invention adopts the following technical solutions:

[0011] The object of the present invention is to provide an electron beam welding method for an ultra-high purity aluminum target and an aluminum alloy back plate, the electron beam welding method comprising the following steps:

[0012] Prepare an ultra-high purity aluminum target, an aluminum alloy backing plate, and a welding sheet, and place the welding sheet at the welding point between the ultra-high purity aluminum target and the aluminum alloy backing plate. After completing the assembly, perform electron beam welding to achieve the bonding of the ultra-high purity aluminum target and the aluminum alloy backing plate;

[0013] The welding sheet includes Al, Si, Cu and a stable metal element; the stable metal element includes any one of Sc, Zr or Er or a combination of at least two of them.

[0014] It should be noted that, on the welding side close to the ultra-high purity aluminum target material, an annular boss is circumferentially arranged at the outer edge of the aluminum alloy back plate, thereby forming a groove in the middle of the aluminum alloy back plate. Correspondingly, on the welding side close to the aluminum alloy back plate, the middle part of the ultra-high purity aluminum target material protrudes and can be accommodated in the groove of the aluminum alloy back plate; the welding sheet is annular and is placed on the upper surface of the annular boss of the aluminum alloy back plate.

[0015] The electron beam welding method of the present invention, based on the composition characteristics of the ultra-high purity aluminum target material, adds a welding piece with special components and then performs electron beam welding, wherein the welding piece includes Al, Si, Cu and a stabilizing metal element. The Si element can improve the fluidity of the molten pool and reduce the tendency of crack formation. The Cu element can reduce the surface tension of the molten pool, enhance wettability, reduce unfused defects, and reduce the generation of pores and cracks. The stabilizing metal element can form second-phase particles with Al. For example, the Sc element can form second-phase particles such as Al3Sc with Al. The second-phase particles can remain stable during the welding process with rapid heat input, making the aluminum base material in the heat-affected zone less likely to soften, improving the weld strength and even healing thermal cracks. Furthermore, the stabilizing metal element includes any one of Sc, Zr, or Er, or a combination of at least two. If the stabilizing metal element is a combination of Zr and Er, Zr and Er can act as grain refinement nucleating agents, refine grains, improve interface strength, and inhibit crack propagation. They also readily combine with hydrogen, inhibiting the generation of hydrogen gas and the formation of pores. Furthermore, the Zr and Er combination is less expensive than the Sc combination. If the Zr and Er combination is a Zr content of 0.15±0.03%, the Er content is 0.10±0.03%.

[0016] The electron beam welding method of the present invention utilizes the low melting point and high fluidity of Al, Si, Cu and stable metal elements in the welding piece to enable the metal at the weld position to melt quickly and fully fill the weld, thereby reducing the generation of defects such as pores and cracks. At the same time, the formed second-phase particles are used to improve the welding strength of the weld, and finally an ultra-high purity aluminum target assembly with good weld joint performance and no defects in appearance is obtained.

[0017] As a preferred technical solution of the present invention, the Al content is 70-85%, such as 70%, 72%, 75%, 77%, 80%, 81%, 83% or 85%, etc., the Si content is 4-20%, such as 4%, 6%, 8%, 10%, 12%, 15%, 18% or 20%, etc., the Cu content is 3-5%, such as 3%, 3.5%, 4%, 4.5% or 5%, etc., the content of stable metal elements is 0.2-4%, such as 0.2%, 0.5%, 1%, 1.5%, 2%, 2.3%, 2.5%, 2.7%, 3%, 3.3%, 3.5%, 3.7% or 4%, etc., and the total content of other elements is ≤1%.

[0018] As a preferred technical solution of the present invention, the welding sheet includes Al, Si, Cu and Sc. In terms of mass percentage, the Al content is 70-85%, for example, 70%, 72%, 75%, 77%, 80%, 81%, 83% or 85%, etc., the Si content is 4-20%, for example, 4%, 6%, 8%, 10%, 12%, 15%, 18% or 20%, etc., the Cu content is 3-5%, for example, 3%, 3.5%, 4%, 4.5% or 5%, etc., the Sc content is 2-4%, for example, 2%, 2.3%, 2.5%, 2.7%, 3%, 3.3%, 3.5%, 3.7% or 4%, etc., and the total content of other elements is ≤1%.

[0019] As a preferred technical solution of the present invention, the thickness of the welding sheet is 0.1-2 mm, for example, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm or 2 mm, etc.

[0020] As a preferred technical solution of the present invention, the purity of the ultra-high purity aluminum target material is ≥5N5.

[0021] Preferably, the aluminum alloy material grade of the aluminum alloy back plate includes any one of A5083, A5052, A6061, A2024 or A1060.

[0022] As a preferred technical solution of the present invention, the assembly includes: first fixing the welding sheet and the aluminum alloy back plate, then fastening the ultra-high purity aluminum target, and pressing the three together tightly by applying pressure.

[0023] Preferably, the fixation is performed using a resistance welding machine, and the parameters of the resistance welding machine are controlled as follows: welding head diameter 2-6 mm, such as 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm or 6 mm, etc., discharge frequency 10-100 Hz, such as 10 Hz, 30 Hz, 50 Hz, 70 Hz, 80 Hz or 100 Hz, etc.

[0024] Preferably, the pressurized pressure is 60-200 MPa, for example, 60 MPa, 80 MPa, 100 MPa, 120 MPa, 140 MPa, 160 MPa, 180 MPa or 200 MPa.

[0025] As a preferred technical solution of the present invention, after the assembly is completed and before the electron beam welding, the weld area with the welding piece is exposed through finishing turning.

[0026] As a preferred technical solution of the present invention, the tool for finishing turning is a tungsten steel alloy tool, the spindle speed is 200-500r / min, such as 200r / min, 250r / min, 300r / min, 350r / min, 400r / min, 450r / min or 500r / min, etc., the feed rate is 0.1-0.6mm / r, such as 0.1mm / r, 0.2mm / r, 0.3mm / r, 0.4mm / r, 0.5mm / r or 0.6mm / r, etc., and the cutting depth is 0.1-1.0mm, such as 0.1mm, 0.3mm, 0.5mm, 0.6mm, 0.8mm or 1.0mm, etc.

[0027] As a preferred technical solution of the present invention, the electron beam welding includes preheating, welding and modification performed in sequence.

[0028] As a preferred technical solution of the present invention, the preheating includes: using an electron beam to preheat along the weld for one circle, controlling the voltage of the electron beam to 40-100kV, such as 40kV, 50kV, 60kV, 70kV, 80kV, 90kV or 100kV, etc., the beam current is 5-20mA, such as 5mA, 8mA, 10mA, 12mA, 15mA, 18mA or 20mA, etc., and the linear speed is 5-20mm / s, such as 5mm / s, 8mm / s, 10mm / s, 12mm / s, 15mm / s, 18mm / s or 20mm / s, etc.

[0029] Preferably, the welding includes: using an electron beam to weld a circle along the weld, controlling the voltage of the electron beam to be 40-130kV, such as 40kV, 60kV, 70kV, 80kV, 100kV, 110kV or 130kV, etc., the beam current is 30-70mA, such as 30mA, 35mA, 40mA, 45mA, 50mA, 55mA, 60mA, 65mA or 70mA, etc., and the linear speed is 10-20mm / s, such as 10mm / s, 11mm / s, 13mm / s, 15mm / s, 16mm / s, 18mm / s or 20mm / s, etc.

[0030] Preferably, the modification includes: using an electron beam to perform a circle of repair welding along the weld, controlling the voltage of the electron beam to be 40-90 kV, such as 40 kV, 50 kV, 60 kV, 70 kV, 80 kV or 90 kV, etc., the beam current to be 10-50 mA, such as 10 mA, 15 mA, 20 mA, 25 mA, 30 mA, 35 mA, 40 mA, 45 mA or 50 mA, etc., and the linear speed to be 5-20 mm / s, such as 5 mm / s, 8 mm / s, 10 mm / s, 12 mm / s, 15 mm / s, 18 mm / s or 20 mm / s, etc.

[0031] The present invention provides an electron beam welding method for an ultra-high purity aluminum target and an aluminum alloy back plate, the electron beam welding method comprising the following steps:

[0032] (1) Processing: Ultra-high purity aluminum target and aluminum alloy back plate of required size are obtained by machining, and annular pieces to be welded are cut out by laser; wherein the purity of the ultra-high purity aluminum target is ≥5N5; the aluminum alloy material grade of the aluminum alloy back plate includes any one of A5083, A5052, A6061, A2024 or A1060; the welding piece is Al-Si-Cu-Sc alloy, Al: 70-85%, Si: 4-20%, Cu: 3-5%, Sc: 2-4%, and the total of other elements: ≤1%; the thickness of the welding piece is 0.1-2 mm;

[0033] (2) Cleaning: The processed ultra-high purity aluminum target, aluminum alloy back plate, and welding piece are ultrasonically cleaned with pure water for 2-8 minutes, ultrasonically cleaned with isopropyl alcohol for 3-10 minutes, and dried for 30-90 minutes to remove metal dust, oil stains, oxides and other dirt on the surface of the ultra-high purity aluminum target, aluminum alloy back plate, and welding piece;

[0034] (3) Assembly and pressurization: First, use a resistance welding machine to fix the cleaned welding piece on the aluminum alloy backing plate. The resistance welding machine parameters are controlled as follows: welding head diameter 2-6 mm, discharge frequency 10-100 Hz; then, the backing plate with the welding piece fixed is assembled with the target material, and the high-purity aluminum target, aluminum alloy backing plate, and welding piece are tightly squeezed together by external pressure. The pressure of the pressurization is controlled to be 60-200 MPa;

[0035] If the gap between the target, backing plate, and welding piece is large after assembly, it will not be conducive to the molten pool formed after electron beam welding to fill the weld, and there will be a risk of leakage. In addition, if the gap is too large, the welding piece may fall out of the weld during subsequent fine turning, damaging the product.

[0036] (4) Processing and cleaning: The extruded integral component is subjected to fine turning on a CNC lathe. The fine turning process parameters are as follows: the tool is a tungsten steel alloy tool, the spindle speed is 200-500 r / min, the feed rate is 0.1-0.6 mm / r, and the cutting depth is 0.1-1.0 mm. The weld area with the added welding piece is turned out, that is, the weld area with the welding piece is exposed. If the weld surface quality is poor, the weld is not clear or there are burrs on the surface, it will make it impossible to position the electron beam during welding, resulting in welding deviation or tip discharge. Therefore, fine turning is required to make the weld surface smooth.

[0037] After finishing turning, clean the product again. Use pure water ultrasonic cleaning for 2-6 minutes, isopropyl alcohol ultrasonic cleaning for 5-10 minutes, and dry for 30-90 minutes to remove metal chips, oil stains, oxides and other dirt on the target surface. If the weld surface is dirty, it will cause violent discharge during electron beam welding of aluminum targets, resulting in poor product welding quality and low welding strength. The violent discharge will seriously affect the product appearance and cause batch scrapping.

[0038] (5) Preparation before welding: Use acetone to wipe the weld surface before welding to ensure the cleanliness of the target material and the weld position;

[0039] (6) Vacuuming: Move the cleaned aluminum target into the electron beam vacuum chamber and isolate and evacuate it. Wait until the vacuum degree of the electron gun is less than 8.0×10 -3 MPa, the vacuum degree of the welding chamber is ≤8.0×10 -2 MPa can start welding;

[0040] (7) Preheating: Start vacuum electron beam welding, use a voltage of 40-100KV, a beam current of 5-20mA, and a linear speed of 5-20mm / s, and preheat along the weld.

[0041] (8) Welding: vacuum electron beam welding is performed using a voltage of 40-130 kV, a beam current of 30-70 mA, and a linear speed of 10-20 mm / s, and welding is performed along the weld seam in a circle;

[0042] (9) Modification: Finally, use a voltage of 40-90KV, a beam current of 10-50mA, and a linear speed of 5-20mm / s to repair the weld and complete the welding.

[0043] The electron beam welding method of the present invention optimizes the processing and cleaning process of the high-purity aluminum target before electron beam welding, utilizes external pressure to squeeze the target material, backing plate, and welding sheet together, and adds a special Al-Si-Cu-Sc alloy welding sheet at the position to be welded by the electron beam. Without affecting the sputtering performance of the target material, it can obtain an ultra-high-purity aluminum target material that is free of discharge during welding, free of defects after welding, with high weld strength and a high welding pass rate, and meets production and use requirements. The electron beam welding method of the present invention has a simple process and high production efficiency. Compared with existing technologies, it greatly reduces the reflow and scrapping of products due to defects such as discharge during welding, pores, cracks, etc. after welding, improves the strength of electron beam welding, and reduces production costs, which is conducive to the promotion of large-scale industrial production.

[0044] Compared with the existing technical solutions, the present invention has at least the following beneficial effects:

[0045] The electron beam welding method described in the present invention has better welding effects, greatly reduces the occurrence of electron beam welding defects, significantly improves the existing ultra-high purity aluminum target welding qualification rate, ensures welding strength, reduces production scrap costs, and improves production efficiency. It provides a new solution to the existing ultra-high purity aluminum target electron beam welding problems and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a structural schematic diagram of an electron beam welding method provided by a specific embodiment of the present invention;

[0047] Among them, 1-ultra-high purity aluminum target; 2-aluminum alloy backing plate; 3-welding sheet;

[0048] Figure 2 This is a diagram showing the appearance of the weld obtained in Example 1 of the present invention;

[0049] Figure 3 This is a diagram showing the appearance of the weld obtained in Example 2 of the present invention;

[0050] Figure 4 This is a diagram showing the appearance of the weld obtained in Example 4 of the present invention;

[0051] Figure 5 This is a diagram showing the appearance of the weld obtained in Example 5 of the present invention;

[0052] Figure 6 This is a diagram showing the appearance of the weld obtained in Comparative Example 1 of the present invention;

[0053] Figure 7 This is a diagram showing the appearance of the weld obtained in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0054] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0055] To better illustrate the present invention and facilitate understanding of the technical solutions of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0056] See also Figure 1 A specific embodiment of the present invention provides an electron beam welding method for an ultra-high purity aluminum target and an aluminum alloy back plate, the electron beam welding method comprising the following steps:

[0057] Prepare an ultra-high purity aluminum target 1, an aluminum alloy backing plate 2, and a welding piece 3, and place the welding piece 3 at the welding point between the ultra-high purity aluminum target 1 and the aluminum alloy backing plate 2. After completing the assembly, perform electron beam welding to achieve the bonding of the ultra-high purity aluminum target 1 and the aluminum alloy backing plate 2;

[0058] The welding sheet 3 includes Al, Si, Cu and a stable metal element; the stable metal element includes any one of Sc, Zr or Er or a combination of at least two of them.

[0059] Example 1

[0060] This embodiment provides an electron beam welding method for an ultra-high purity aluminum target and an aluminum alloy back plate, the electron beam welding method comprising the following steps:

[0061] (1) Processing: Ultra-high purity aluminum target and aluminum alloy back plate of required size are obtained by machining, and annular pieces to be welded are cut by laser; wherein the purity of the ultra-high purity aluminum target is ≥5N5; the aluminum alloy material grade of the aluminum alloy back plate is A5083; the welding piece is Al-Si-Cu-Sc alloy, and the mass percentage is: Al: 80%, Si: 12%, Cu: 4%, Sc: 3%, and the total of other elements is ≤1%; the thickness of the welding piece is 0.5 mm;

[0062] (2) Cleaning: The processed ultra-high purity aluminum target, aluminum alloy back plate, and welding piece are ultrasonically cleaned with pure water for 5 minutes, ultrasonically cleaned with isopropyl alcohol for 10 minutes, and dried for 60 minutes to remove metal dust, oil stains, oxides and other dirt on the surface of the ultra-high purity aluminum target, aluminum alloy back plate, and welding piece;

[0063] (3) Assembly and pressurization: First, use a resistance welding machine to fix the cleaned welding piece on the aluminum alloy backing plate. The resistance welding machine parameters are controlled as follows: welding head diameter 2mm, discharge frequency 50Hz; then, the backing plate with the welding piece fixed is assembled with the target material, and the high-purity aluminum target, aluminum alloy backing plate, and welding piece are tightly squeezed together by external pressure. The pressure of the pressurization is controlled to be 120MPa.

[0064] (4) Processing and cleaning: The extruded integral component is subjected to fine turning on a CNC lathe. The fine turning process parameters are as follows: the tool is a tungsten steel alloy tool, the spindle speed is 350 r / min, the feed rate is 0.4 mm / r, and the cutting depth is 0.7 mm. The weld area with the added welding piece is turned out, that is, the weld area with the welding piece is exposed;

[0065] After finishing turning, the product is cleaned again, using pure water ultrasonic cleaning for 5 minutes, isopropyl alcohol ultrasonic cleaning for 10 minutes, and drying for 60 minutes to remove metal chips, oil stains, oxides and other dirt on the surface of the target;

[0066] (5) Preparation before welding: Use acetone to wipe the weld surface before welding to ensure the cleanliness of the target material and the weld position;

[0067] (6) Vacuuming: Move the cleaned aluminum target into the electron beam vacuum chamber and isolate and evacuate it. Wait until the vacuum degree of the electron gun is less than 8.0×10 -3 MPa, the vacuum degree of the welding chamber is ≤8.0×10 -2 MPa can start welding;

[0068] (7) Preheating: Start vacuum electron beam welding, use 80KV voltage, 10mA beam current, 15mm / s linear speed, and preheat along the weld seam;

[0069] (8) Welding: vacuum electron beam welding was performed using a voltage of 80 kV, a beam current of 60 mA, and a linear speed of 15 mm / s, with one circle welded along the weld seam;

[0070] (9) Modification: Finally, use 60KV voltage, 40mA beam current, and 15mm / s linear speed to repair the weld seam and complete the welding.

[0071] Figure 2 The appearance diagram of the weld obtained in this embodiment is shown. It can be seen that the weld obtained in this embodiment has no defects such as pores and cracks, and meets the customer's requirements for weld appearance.

[0072] Example 2

[0073] This embodiment provides an electron beam welding method for an ultra-high purity aluminum target and an aluminum alloy back plate. Compared with Example 1, the only difference is that the welding sheet is an Al-Si-Cu-Sc alloy, and the mass percentage is Al: 77%, Si: 12%, Cu: 7%, Sc: 3%, and the total of other elements is ≤1%.

[0074] Figure 3 The appearance of the weld obtained in this embodiment is shown, and it can be seen that the weld obtained in this embodiment has a small amount of defects such as pores and cracks.

[0075] Example 3

[0076] This embodiment provides an electron beam welding method for an ultra-high purity aluminum target and an aluminum alloy back plate. Compared with Example 1, the only difference is that the welding sheet is an Al-Si-Cu-Sc alloy, and the mass percentage is Al: 84%, Si: 12%, Cu: 0.1%, Sc: 3%, and the total of other elements is ≤1%.

[0077] The weld appearance shown in this example is Figure 3 Similarly, the weld obtained in this embodiment has a small amount of defects such as pores and cracks.

[0078] Example 4

[0079] This embodiment provides an electron beam welding method for an ultra-high purity aluminum target and an aluminum alloy back plate. Compared with Example 1, the only difference is that the welding sheet is an Al-Si-Cu-Sc alloy, and the mass percentage is Al: 83%, Si: 12%, Cu: 4%, Sc: 0.3%, and the total of other elements is ≤1%.

[0080] Figure 4 The appearance of the weld obtained in this embodiment is shown. It can be seen that the weld obtained in this embodiment has many defects such as pores and cracks, and the defects are mainly cracks.

[0081] Example 5

[0082] This embodiment provides an electron beam welding method for an ultra-high purity aluminum target and an aluminum alloy back plate. Compared with Example 1, the only difference is that the welding sheet is an Al-Si-Cu-Sc alloy, and the mass percentage is Al: 77%, Si: 12%, Cu: 4%, Sc: 6%, and the total of other elements is ≤1%.

[0083] Figure 5 The appearance of the weld obtained in this embodiment is shown. It can be seen that the weld obtained in this embodiment has a small amount of defects such as pores and cracks, and the defects are mainly cracks.

[0084] Example 6

[0085] This embodiment provides an electron beam welding method for an ultra-high purity aluminum target and an aluminum alloy back plate. Compared with Example 1, the only difference is that the welding sheet is an Al-Si-Cu-Sc alloy, and the mass percentage is Al: 89%, Si: 3%, Cu: 4%, Sc: 3%, and the total of other elements is ≤1%.

[0086] The weld appearance shown in this example is Figure 5 Similarly, the weld obtained in this embodiment has a small amount of defects such as pores and cracks, and the defects are mainly cracks.

[0087] Example 7

[0088] This embodiment provides an electron beam welding method for an ultra-high purity aluminum target and an aluminum alloy back plate. Compared with Example 1, the only difference is that the welding sheet is an Al-Si-Cu-Sc alloy, and the mass percentage is Al: 70%, Si: 22%, Cu: 4%, Sc: 3%, and the total of other elements is ≤1%.

[0089] The weld appearance shown in this example is Figure 5 Similarly, the weld obtained in this embodiment has a small amount of defects such as pores and cracks, and the defects are mainly cracks.

[0090] Example 8

[0091] This embodiment provides an electron beam welding method for an ultra-high purity aluminum target and an aluminum alloy back plate. Compared with Example 1, the only difference is that the preheating of step (7) is directly omitted and the welding of step (8) is directly performed.

[0092] Example 9

[0093] This embodiment provides an electron beam welding method for an ultra-high purity aluminum target and an aluminum alloy back plate. Compared with Example 1, the only difference is that the modification of step (9) is omitted, that is, after the welding of step (8) is completed, the modification of step (9) is no longer performed.

[0094] Comparative Example 1

[0095] This comparative example provides an electron beam welding method. Compared with Example 1, the only difference is that the welding sheet is A4047 aluminum alloy; after testing, based on mass percentage, Al: 86.3%, Si: 12.2%, and the total content of other elements is ≤1.5%, of which Cu: 0.3%, and Sc is not detected.

[0096] Figure 6 The appearance of the weld obtained in this comparative example is shown, and it can be seen that the weld obtained in this comparative example has a large number of defects such as pores and cracks.

[0097] Comparative Example 2

[0098] This comparative example provides an electron beam welding method. Compared with Example 1, the only difference is that the welding sheet is an Al-Si-Cu-Sc alloy, and the mass percentage is Al: 93%, Si: 4%, Cu: 2%, Sc: 0.3%, and the total of other elements is ≤1%.

[0099] Figure 7 The appearance display diagram of the weld obtained in this comparative example is shown. It can be seen that the weld obtained in this comparative example has many defects such as pores and cracks, and the overall defects are improved compared with comparative example 1.

[0100] The target material assemblies obtained by electron beam welding in the above embodiment and the comparative example were subjected to welding bonding rate testing, and the appearance of the welds corresponding to the electron beam welding in the above embodiment and the comparative example were visually observed to determine whether defects such as pores and cracks were generated. The relevant results are summarized in Table 1.

[0101] Table 1

[0102] project Welding bonding rate Weld appearance Example 1 100％ No defects such as pores and cracks Example 2 100％ There are a small number of defects such as pores and cracks Example 3 100％ There are a small number of defects such as pores and cracks Example 4 100％ There are many defects such as pores and cracks, and the defects are mainly cracks. Example 5 100％ There are a small number of defects such as pores and cracks, and the defects are mainly cracks. Example 6 100％ There are a small number of defects such as pores and cracks, and the defects are mainly cracks. Example 7 100％ There are a small number of defects such as pores and cracks, and the defects are mainly cracks. Example 8 99.5％ No defects such as pores and cracks Example 9 99.7％ No defects such as pores and cracks Comparative Example 1 100％ There are a lot of defects such as pores and cracks Comparative Example 2 100％ There are many defects such as pores and cracks

[0103] The following points can be seen from Table 1:

[0104] (1) Comparing Example 1 with Examples 2 and 3, if the Cu content in the welding sheet exceeds 3-5%, the surface tension of the molten pool cannot be effectively reduced, the wettability is low, and the lack of fusion defects cannot be effectively reduced, resulting in a small amount of defects such as pores and cracks in the weld.

[0105] (2) Comparing Example 1 with Examples 4 and 5, the Sc element in the weld sheet in Example 4 exceeded the minimum limit of 2-4%, being only 0.3%. The generated second-phase particles such as Al3Sc were relatively few, and the aluminum base material in the heat-affected zone softened rapidly, reducing the weld strength and making it difficult for thermal cracks to heal. As a result, the weld had many defects such as pores and cracks, and the defects were mainly cracks. In Example 5, the Sc element in the weld sheet exceeded the maximum limit of 2-4%, increasing to 6%. The generated second-phase particles such as Al3Sc were excessive, which in turn affected the healing of thermal cracks. As a result, the weld had a small amount of defects such as pores and cracks, and the defects were mainly cracks.

[0106] (3) Comparing Example 1 with Examples 6 and 7, the Si content of the welding sheet in Example 6 exceeded the minimum limit of 4-20% by only 3%, affecting the fluidity of the molten pool. The resulting weld had a small amount of defects such as pores and cracks, with the defects mainly being cracks. In Example 7, the Si content of the welding sheet exceeded the maximum limit of 4-20%, increasing to 22%, still affecting the fluidity of the molten pool. The resulting weld had a small amount of defects such as pores and cracks, with the defects mainly being cracks.

[0107] (4) Comparing Example 1 with Examples 8 and 9, although Examples 8 and 9 all use the same welding pieces as Example 1, and the weld appearance does not have defects such as pores and cracks, the omission of preheating or finishing in electron beam welding will affect the welding bonding rate;

[0108] (5) Comparing Example 1 with Comparative Examples 1 and 2, the present invention adds a special Al-Si-Cu-Sc alloy welding sheet at the position to be welded by the electron beam, which can obtain an ultra-high purity aluminum target material with no discharge during welding, no defects after welding, high weld strength, high welding qualification rate, and meeting the production and use requirements without affecting the sputtering performance of the target material.

[0109] While the present invention is described through the above-described embodiments to illustrate the detailed structural features of the present invention, the present invention is not limited to these detailed structural features, nor does it necessarily rely on these detailed structural features for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for selected components, additions of auxiliary components, and selection of specific embodiments, etc., fall within the scope of protection and disclosure of the present invention.

[0110] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0111] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0112] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for electron beam welding of an ultra-high purity aluminum target and an aluminum alloy back plate, characterized in that: The electron beam welding method comprises the following steps: Prepare an ultra-high purity aluminum target, an aluminum alloy backing plate, and a welding sheet, and place the welding sheet at the welding point between the ultra-high purity aluminum target and the aluminum alloy backing plate. After completing the assembly, perform electron beam welding to achieve the bonding of the ultra-high purity aluminum target and the aluminum alloy backing plate; The welding sheet includes Al, Si, Cu and a stable metal element; the stable metal element includes any one of Sc, Zr or Er or a combination of at least two of them.

2. The electron beam welding method according to claim 1, wherein Calculated by mass percentage, the Al content is 70-85%, the Si content is 4-20%, the Cu content is 3-5%, the stabilizing metal element content is 0.2-4%, and the total content of other elements is ≤1%.

3. The electron beam welding method according to claim 2, wherein: The welding sheet comprises Al, Si, Cu and Sc. Calculated by mass percentage, the Al content is 70-85%, the Si content is 4-20%, the Cu content is 3-5%, the Sc content is 2-4%, and the total content of other elements is ≤1%.

4. The electron beam welding method according to any one of claims 1 to 3, characterized in that: The thickness of the welding sheet is 0.1-2 mm.

5. The electron beam welding method according to any one of claims 1 to 4, characterized in that: The purity of the ultra-high purity aluminum target is ≥5N5; Preferably, the aluminum alloy material grade of the aluminum alloy back plate includes any one of A5083, A5052, A6061, A2024 or A1060.

6. The electron beam welding method according to any one of claims 1 to 5, characterized in that: The assembly includes: first fixing the welding sheet and the aluminum alloy back plate, then buckling the ultra-high purity aluminum target, and pressing the three together tightly by applying pressure; Preferably, the fixing is performed by a resistance welding machine, and the parameters of the resistance welding machine are controlled as follows: welding head diameter 2-6 mm, discharge frequency 10-100 Hz; Preferably, the pressurized pressure is 60-200 MPa.

7. The electron beam welding method according to any one of claims 1 to 6, characterized in that: After the assembly is completed and before the electron beam welding, the weld area with the weld tab is exposed by finishing turning.

8. The electron beam welding method according to claim 7, characterized in that The tool for finishing turning is a tungsten steel alloy tool, the spindle speed is 200-500r / min, the feed rate is 0.1-0.6mm / r, and the cutting depth is 0.1-1.0mm.

9. The electron beam welding method according to any one of claims 1 to 8, characterized in that: The electron beam welding includes preheating, welding and finishing which are performed in sequence.

10. The electron beam welding method according to claim 9, characterized in that The preheating comprises: using an electron beam to preheat along the weld seam for one circle, controlling the electron beam voltage to be 40-100 kV, the beam current to be 5-20 mA, and the linear speed to be 5-20 mm / s; Preferably, the welding comprises: welding a circle along the weld using an electron beam, controlling the electron beam voltage to be 40-130 kV, the beam current to be 30-70 mA, and the linear speed to be 10-20 mm / s; Preferably, the modification includes: using an electron beam to perform a repair weld along the weld seam, controlling the electron beam voltage to be 40-90 kV, the beam current to be 10-50 mA, and the linear speed to be 5-20 mm / s.

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