A sputtering target assembly with a back plate in a vacuum environment and a bonding composite solder and a welding process thereof

Abstract

The present invention relates to a sputtering target assembly with a back plate in a vacuum environment and a bonding composite solder and a welding process thereof, and belongs to the technical field of sputtering target preparation. In view of the scarcity and high cost of high-purity indium solder, by blending elements such as tin, zinc, copper, silver, boron, antimony, tellurium, bismuth and yttrium, and introducing NaCl, KCl, LiF mixed molten salt as a protective layer, a solder with excellent thermal conductivity, low melting point, high fluidity and high strength is prepared; at the same time, the welding process is optimized, including plasma cleaning, roughening pretreatment, high vacuum welding environment, ultrasonic assisted welding and slow cooling steps, which significantly improves the bonding strength between the target and the back plate, reduces thermal resistance, ensures the stability and durability of the sputtering target assembly, and extends the service life.

Description

Technical Field

[0001] The invention belongs to the technical field of sputtering target material preparation, and relates to a sputtering target material assembly with a back plate in a vacuum environment and a welding process thereof. Background Art

[0002] In the core application of vacuum coating technology, sputtering targets play a vital role. Their physical and chemical properties directly and significantly affect the final quality and production efficiency of the coating layer. The traditional bonding welding process between the target and the backing plate generally faces challenges such as high thermal resistance, substandard bonding strength, and significant accumulation of residual stress. These defects are particularly significant under high-power sputtering conditions, which seriously restricts the stability of the coating process and the improvement of coating quality.

[0003] In view of this, it is particularly urgent and of great significance to explore and develop a new high-efficiency bonding welding technology designed for vacuum environment and for sputtering target components with backing plates. This technology aims to effectively reduce the thermal resistance in the welding process by optimizing welding interface processing, innovating welding methods or introducing new welding materials, significantly improve the bonding strength between the target and the backing plate, and effectively control or even eliminate welding residual stress, thereby ensuring that the target component can maintain stable performance output under high-power sputtering conditions, laying a solid foundation for the high-quality and high-efficiency application of vacuum coating technology. Summary of the invention

[0004] The purpose of the present invention is to provide a sputtering target assembly with a backing plate bound composite solder and a welding process thereof in a vacuum environment. The composite solder has excellent thermal conductivity and electrical conductivity, a low melting point and good fluidity, and high strength. The welding process has the characteristics of low thermal resistance, high quality and high bonding strength.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A sputtering target assembly with a back plate in a vacuum environment has a composite solder composition, wherein the composite solder composition comprises, by mass percentage, 50-60% tin, 10-20% zinc, 5-10% copper, 5-10% boron, 2-3% silver, 1-2% bismuth, 0.5-1% antimony, 0.2-0.5% yttrium, 0.1-0.3% tellurium, and 2-5% mixed molten salt.

[0007] The preparation method of composite solder is as follows:

[0008] S1.1: According to the ratio of each metal in the formula, use a high-precision electronic balance to accurately weigh each raw material. The purity of all raw materials is above 99.9%;

[0009] S1.2: The weighed raw materials were placed in a mortar and premixed for 30 min, and then the premixed raw materials were further fully mixed using a ball mill. The ball milling time was 2 h and the ball milling speed was 150 r / min to obtain a mixture A;

[0010] S1.3: Preheat the box-type resistance furnace to 70 °C, add mixture A and mixed molten salt into the box-type resistance furnace, and increase the temperature at a rate of 5 °C / min within a temperature range of 70-500 °C;

[0011] S1.4: After the raw materials are completely melted, add the slag remover, keep the temperature at 500 °C for 30 min, and then gradually cool down at a rate of 10 °C / min to obtain a refined melt product;

[0012] S1.5: pouring the refined molten product into a preheated mold, demoulding it after natural cooling and solidification, performing necessary trimming and cleaning, removing burrs and flash, and obtaining the composite solder.

[0013] Furthermore, the ball milling method in S1.2 is 3 minutes of ball milling followed by 2 minutes of rest.

[0014] Furthermore, the mixed molten salt is a mixture of NaCl, KCl and LiF, wherein the mass ratio of NaCl, KCl and LiF is 2:3:1.

[0015] Furthermore, the slag remover in S1.4 is any one or a combination of graphite powder and borax.

[0016] A sputtering target assembly with a backing plate is provided for bonding and welding in a vacuum environment. The specific process of the sputtering target assembly with a backing plate is as follows:

[0017] S5.1: Use plasma to deeply clean the target and backing surface, with a vacuum degree of 1×10 -3 Pa, the argon flow rate was 10 sccm, the RF power was 300 W, and the cleaning time was 10 min;

[0018] S5.2: Fix the cleaned target and back plate on the sandblasting equipment, and use titanium dioxide sand to sandblast the welding surface of the target and the back plate. Control the sandblasting pressure to 5~10 kg / cm², the sandblasting distance to 30~40 cm, and the sandblasting angle to 40~60°;

[0019] S5.3: Use a high vacuum pump to evacuate the welding chamber to a vacuum degree of ≤10 -6 Pa, monitors and maintains stable vacuum in the welding chamber;

[0020] S5.4: Place the pre-treated target and backing plate on the welding table, ensure that they are in close contact and accurately positioned, heat the welding table to 300 °C, make the composite solder begin to melt, and introduce ultrasonic vibration at the same time, maintain ultrasonic vibration and heating for 20 minutes;

[0021] S5.5: Slowly cool the welding room to room temperature, perform visual inspection and X-ray flaw detection on the welding parts in turn to ensure that the welding quality meets the requirements, and perform necessary surface treatment and cleaning on the target assembly for subsequent use.

[0022] Furthermore, after the sandblasting in S5.2, the welding surface roughness Ra of the target material and the back plate reaches 0.25 μm.

[0023] Furthermore, the ultrasonic frequency in S5.4 is 7 kHz.

[0024] Furthermore, in S5.5, the welding chamber is slowly cooled to room temperature at a rate of 2°C / min.

[0025] First, since high-purity indium is the most widely used type of solder for sputtering target assembly bonding, and has problems such as rarity and high cost, the present invention utilizes a variety of metals and non-metallic substances to prepare a composite solder. Tin with good electrical conductivity, thermal conductivity and solderability is selected as the main component of the solder. Its low melting point makes the solder easy to melt and form a uniform welding joint; the introduction of zinc can form a solid solution with tin, significantly improving the mechanical properties of the solder such as strength and hardness, while reducing the melting point and improving fluidity; the introduction of copper and silver can significantly improve the electrical conductivity and thermal conductivity of the solder, while increasing the strength of the solder; the introduction of boron, antimony and tellurium can refine the grain structure of the solder, thereby improving the strength and hardness of the solder. The fine grains help reduce stress concentration during welding and improve the toughness of the welded joint. At the same time, it can also improve the wettability of the solder to the base material, making it easier for the solder to spread on the surface of the base material to form a uniform welding layer; the introduction of a small amount of bismuth can improve the fluidity of the solder, making it easier for the solder to fill the weld and form a dense welding joint; the introduction of a trace amount of yttrium can improve the microstructure of the solder, reduce defects and cracks during welding, and improve the quality of the welded joint. The appropriately proportioned mixed molten salt of NaCl, KCl and LiF forms a layer of liquid protective film at high temperature, covering the surface of the alloy solder, isolating the direct contact between the air and the solder, effectively preventing the solder from undergoing oxidation reaction at high temperature, and maintaining the purity and performance stability of the solder; at the same time, the mixture of NaCl, KCl and LiF has a lower eutectic point when the mass ratio is 2:3:1, so that it can remain liquid at a lower temperature. At this time, the physical properties of the molten salt, such as viscosity and surface tension, make it have better fluidity, and can cover the solder surface more evenly, improving the protective effect. Ultimately, the prepared composite solder has excellent thermal conductivity and electrical conductivity, a lower melting point, good fluidity and high strength, and has good welding performance.

[0026] In addition, in order to improve the bonding strength between the target and the back plate, reduce thermal resistance, and ensure the stability and durability of the target assembly during the subsequent sputtering process, the steps, methods and parameter settings of the welding process were optimized. The target and back plate surfaces were cleaned using efficient plasma technology. The high-energy particles in the plasma can impact the target and back plate surfaces, remove surface pollutants, oxides and other impurities, improve the surface cleanliness and activity, and facilitate the subsequent welding process. Titanium dioxide sand was used for further pretreatment to achieve a welding surface roughness Ra of 0.25 μm for the target and back plate, significantly increasing the contact area between the target and the back plate, so that the composite solder can better penetrate into these tiny bumps after melting, forming a mechanical locking effect, thereby significantly improving the bonding strength of the welded joint; at the same time, it helps the solder to discharge gas and impurities during solidification, reduce the formation of welding defects such as pores and slag inclusions, and further improve the welding quality. Pumping the welding chamber to a high vacuum avoids the interference of oxygen during the welding process and prevents oxidation of the welding surface. It is also conducive to the uniform melting and flow of the composite solder during the welding process. The vacuum degree in the welding chamber is monitored and maintained to ensure the smooth progress of the welding process. Introducing ultrasonic vibration while heating the welding can promote the uniform distribution and penetration of the solder and improve the welding quality. In addition, ultrasonic vibration can also generate local high temperature and high pressure, which helps to remove tiny bubbles and impurities between the welding surfaces and enhance the density of the welding. After the welding is completed, the welding chamber is slowly cooled to room temperature at a rate of 2 ℃ / min to avoid internal stress or cracks in the welded parts due to rapid cooling. The combined effect of the above steps makes the target assembly have good stability and durability in the subsequent use process, significantly improving the service life of the target assembly.

[0027] Beneficial effects of the present invention:

[0028] (1) In response to the scarcity and high cost of high-purity indium solder, the present invention has developed a multi-metal and non-metal composite solder, which is mainly composed of tin, combined with zinc, copper and silver to improve mechanical properties and electrical and thermal conductivity; boron, antimony and tellurium refine the grains, enhance strength and wettability; bismuth improves fluidity; yttrium optimizes the microstructure and reduces defects. A mixed molten salt of NaCl, KCl and LiF is used as a protective film to prevent oxidation and maintain stable performance. The composite solder has a low melting point, high electrical and thermal conductivity, high strength and good welding performance, which significantly improves the binding effect of sputtering target components.

[0029] (2) The present invention optimizes the welding process, significantly improves the bonding strength between the target and the back plate, reduces thermal resistance, and ensures the stability and durability of the sputtering process. High-efficiency plasma cleaning and titanium dioxide sand pretreatment are used to enhance surface cleanliness and contact area, promote solder penetration, reduce welding defects, and improve welding quality; high vacuum environment prevents oxidation, and ultrasonic vibration promotes uniform distribution and penetration of solder, enhancing welding density; slow cooling avoids internal stress, and comprehensively improves the stability, durability and service life of the target assembly, which has significant technical progress and application value. DETAILED DESCRIPTION

[0030] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0031] Formula ratio 1: 55% tin, 20% zinc, 10% copper, 5% boron, 3% silver, 2% bismuth, 0.5% antimony, 0.3% yttrium, 0.2% tellurium, 4% mixed molten salt;

[0032] Formula ratio 2: 60% tin, 15% zinc, 10% copper, 5% boron, 3% silver, 2% bismuth, 0.5% antimony, 0.3% yttrium, 0.2% tellurium, 4% mixed molten salt;

[0033] Formula ratio 3: 65% tin, 10% zinc, 10% copper, 5% boron, 3% silver, 2% bismuth, 0.5% antimony, 0.3% yttrium, 0.2% tellurium, 4% mixed molten salt;

[0034] The mixed molten salt is a mixture of NaCl, KCl and LiF, wherein the mass ratio of NaCl, KCl and LiF is 2:3:1.

[0035] A sputtering target assembly with a back plate in a vacuum environment is bonded with a composite solder, and the composite solder preparation method is as follows:

[0036] S1.1: According to the ratio of each metal in the formula, use a high-precision electronic balance to accurately weigh each raw material. The purity of all raw materials is above 99.9%;

[0037] S1.2: The weighed raw materials were placed in a mortar and premixed for 30 min, and then the premixed raw materials were further fully mixed using a ball mill. The ball milling time was 2 h and the ball milling speed was 150 r / min to obtain a mixture A;

[0038] S1.3: Preheat the box-type resistance furnace to 70 °C, add mixture A and mixed molten salt into the box-type resistance furnace, and increase the temperature at a rate of 5 °C / min within a temperature range of 70-500 °C;

[0039] S1.4: After the raw materials are completely melted, add the slag remover, keep the temperature at 500 °C for 30 min, and then gradually cool down at a rate of 10 °C / min to obtain a refined melt product;

[0040] S1.5: pouring the refined molten product into a preheated mold, demoulding it after natural cooling and solidification, performing necessary trimming and cleaning, removing burrs and flash, and obtaining the composite solder.

[0041] The specific process of the sputtering target assembly bonding welding process with a back plate in a vacuum environment is as follows:

[0042] S5.1: Use plasma to deeply clean the target and backing surface, with a vacuum degree of 1×10 -3 Pa, the argon flow rate was 10 sccm, the RF power was 300 W, and the cleaning time was 10 min;

[0043] S5.2: Fix the cleaned target and back plate on the sandblasting equipment, and use titanium dioxide sand to sandblast the welding surface of the target and the back plate. Control the sandblasting pressure to 5~10 kg / cm², the sandblasting distance to 30~40 cm, and the sandblasting angle to 40~60°;

[0044] S5.3: Use a high vacuum pump to evacuate the welding chamber to a vacuum degree of ≤10 -6 Pa, monitors and maintains stable vacuum in the welding chamber;

[0045] S5.4: Place the pre-treated target and backing plate on the welding table, ensure that they are in close contact and accurately positioned, heat the welding table to 300 °C, make the composite solder begin to melt, and introduce ultrasonic vibration at a frequency of 7 kHz. Maintain ultrasonic vibration and heating for 20 min;

[0046] S5.5: Slowly cool the welding room to room temperature, perform visual inspection and X-ray flaw detection on the welding parts in turn to ensure that the welding quality meets the requirements, and perform necessary surface treatment and cleaning on the target assembly for subsequent use.

[0047] Example 1

[0048] S1.1: According to the ratio of each metal in Formula 1, use a high-precision electronic balance to accurately weigh each raw material. The purity of all raw materials is above 99.9%;

[0049] S1.2: The weighed raw materials were placed in a mortar and premixed for 30 min, and then the premixed raw materials were further fully mixed using a ball mill. The ball milling time was 2 h and the ball milling speed was 150 r / min to obtain a mixture A;

[0050] S1.3: Preheat the box-type resistance furnace to 70 °C, add mixture A and mixed molten salt into the box-type resistance furnace, and increase the temperature at a rate of 5 °C / min within a temperature range of 70-500 °C;

[0051] S1.4: After the raw materials are completely melted, add 5 wt% graphite powder, keep the temperature at 500 °C for 30 min, and then gradually cool down at a rate of 10 °C / min to obtain a refined melt product;

[0052] S1.5: pouring the refined molten product into a preheated mold, demoulding it after natural cooling and solidification, performing necessary trimming and cleaning, removing burrs and flash, and obtaining the composite solder.

[0053] The specific process of the sputtering target assembly bonding welding process with a back plate in a vacuum environment is as follows:

[0054] S5.1: Use plasma to deeply clean the target and backing surface, with a vacuum degree of 1×10 -3 Pa, the argon flow rate was 10 sccm, the RF power was 300 W, and the cleaning time was 10 min;

[0055] S5.2: Fix the cleaned target and back plate on the sandblasting equipment, and use titanium dioxide sand to sandblast the welding surface of the target and the back plate. The sandblasting pressure is controlled to be 5 kg / cm², the sandblasting distance is 30 cm, and the sandblasting angle is 40°. After sandblasting, the roughness Ra of the welding surface of the target and the back plate reaches 0.25 μm;

[0056] S5.3: Use a high vacuum pump to evacuate the welding chamber to a vacuum degree of ≤10 -6 Pa, monitors and maintains stable vacuum in the welding chamber;

[0057] S5.4: Place the pre-treated target and backing plate on the welding table, ensure that they are in close contact and accurately positioned, heat the welding table to 300 °C, make the composite solder begin to melt, and introduce ultrasonic vibration at a frequency of 7 kHz. Maintain ultrasonic vibration and heating for 20 min;

[0058] S5.5: Slowly cool the welding room to room temperature at a rate of 2 °C / min, perform visual inspection and X-ray flaw detection on the welding parts in turn to ensure that the welding quality meets the requirements, and perform necessary surface treatment and cleaning on the target assembly for subsequent use.

[0059] Example 2

[0060] S1.1: According to the ratio of each metal in Formula 2, use a high-precision electronic balance to accurately weigh each raw material. The purity of all raw materials is above 99.9%;

[0061] S1.2: The weighed raw materials were placed in a mortar and premixed for 30 min, and then the premixed raw materials were further fully mixed using a ball mill. The ball milling time was 2 h and the ball milling speed was 150 r / min to obtain a mixture A;

[0062] S1.3: Preheat the box-type resistance furnace to 70 °C, add mixture A and mixed molten salt into the box-type resistance furnace, and increase the temperature at a rate of 5 °C / min within a temperature range of 70-500 °C;

[0063] S1.4: After the raw materials are completely melted, add 5 wt% borax, keep the temperature at 500 °C for 30 min, and then gradually cool down at a rate of 10 °C / min to obtain a refined melt product;

[0064] S1.5: pouring the refined molten product into a preheated mold, demoulding it after natural cooling and solidification, performing necessary trimming and cleaning, removing burrs and flash, and obtaining the composite solder.

[0065] The welding process is consistent with that in Example 1.

[0066] Example 3

[0067] S1.1: According to the ratio of each metal in Formula 3, use a high-precision electronic balance to accurately weigh each raw material. The purity of all raw materials is above 99.9%;

[0068] S1.2: The weighed raw materials were placed in a mortar and premixed for 30 min, and then the premixed raw materials were further fully mixed using a ball mill. The ball milling time was 2 h and the ball milling speed was 150 r / min to obtain a mixture A;

[0069] S1.3: Preheat the box-type resistance furnace to 70 °C, add mixture A and mixed molten salt into the box-type resistance furnace, and increase the temperature at a rate of 5 °C / min within a temperature range of 70-500 °C;

[0070] S1.4: After the raw materials are completely melted, add 5 wt% graphite powder, keep the temperature at 500 °C for 30 min, and then gradually cool down at a rate of 10 °C / min to obtain a refined melt product;

[0071] S1.5: pouring the refined molten product into a preheated mold, demoulding it after natural cooling and solidification, performing necessary trimming and cleaning, removing burrs and flash, and obtaining the composite solder.

[0072] The welding process is consistent with that in Example 1.

[0073] Comparative Example 1

[0074] High-purity indium is used as solder, and the welding process is consistent with that in Example 1.

[0075] Comparative Example 2

[0076] High purity tin is used as solder, and the welding process is consistent with that in Example 1.

[0077] Comparative Example 3

[0078] The ultrasonic frequency in S5.4 is 5 kHz, and the remaining steps are consistent with Example 1.

[0079] Comparative Example 4

[0080] The ultrasonic frequency in S5.4 is 9 kHz, and the remaining steps are consistent with Example 1.

[0081] Comparative Example 5

[0082] No ultrasonic step is added in S5.4, and the remaining steps are consistent with Example 1.

[0083] The melting points of the examples and comparative examples were tested using a Diamond Osc differential scanning calorimeter. The mass of the sample was about 10 mg. The test temperature range was 50-450° C., and the heating rate was 10° C. / min.

[0084] The thermal conductivity of the embodiments and comparative examples was measured using a Dyna Cool thermal conductivity meter. The test temperature range was 37-97° C. and the sample size was 2 mm×2 mm×8 mm.

[0085] The resistance of the embodiment and the comparative example was measured using a QJ44 double-arm bridge, and the sample size was 10 mm×10 mm×100 mm.

[0086] The wetting angles of the embodiments and comparative examples were tested using a ZDF-5227 high temperature and high vacuum wettability testing device at a test temperature of 300°C, a holding time of 30 min, and a sample size of 3 mm×3 mm×3 mm.

[0087] The welding strength of the sputtering target assembly welded with solder in the embodiment and the comparative example was tested using a WDW-300 electronic universal testing machine, and the experimental steps were in accordance with the GB / T 7314-2017 standard.

[0088] The experimental results are summarized in the following table:

[0089]

[0090] From the data of Examples 1 to 3 and Comparative Examples 1 to 2, it can be seen that the composite solder prepared with tin as the main component and the introduction of zinc, copper, silver and other elements has good thermal conductivity and electrical conductivity, a low melting point and good fluidity. At the same time, the composite material has good welding strength when welding the sputtering target and the back plate, and is expected to become an effective substitute for the expensive high-purity indium solder. From Comparative Examples 3 to 5, it can be seen that introducing ultrasonic vibration in the process and maintaining a certain frequency can greatly promote the penetration of the solder with the back plate and the sputtering target, and obtain a more stable welding effect.

[0091] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A sputtering target assembly with a backing plate in a vacuum environment for bonding composite solder, characterized in that: The composite solder formula is as follows: by mass percentage, 50-60% tin, 10-20% zinc, 5-10% copper, 5-10% boron, 2-3% silver, 1-2% bismuth, 0.5-1% antimony, 0.2-0.5% yttrium, 0.1-0.3% tellurium, 2-5% mixed molten salt, The preparation method of composite solder is as follows: S1.1: According to the ratio of each metal in the formula, use a high-precision electronic balance to accurately weigh each raw material. The purity of all raw materials is above 99.9%; S1.2: The weighed raw materials were placed in a mortar and premixed for 30 min, and then the premixed raw materials were further fully mixed using a ball mill. The ball milling time was 2 h and the ball milling speed was 150 r / min to obtain a mixture A; S1.3: Preheat the box-type resistance furnace to 70 °C, add mixture A and mixed molten salt into the box-type resistance furnace, and increase the temperature at a rate of 5 °C / min within a temperature range of 70-500 °C; S1.4: After the raw materials are completely melted, add the slag remover, keep the temperature at 500 °C for 30 min, and then gradually cool down at a rate of 10 °C / min to obtain a refined melt product; S1.5: pouring the refined molten product into a preheated mold, demoulding it after natural cooling and solidification, performing necessary trimming and cleaning, removing burrs and flash, and obtaining the composite solder.

2. A sputtering target assembly with a back plate for bonding composite solder in a vacuum environment according to claim 1, characterized in that: The ball milling method in S1.2 is 3 minutes per ball milling with 2 minutes of rest.

3. The sputtering target assembly with a back plate in a vacuum environment and a composite solder bonding material according to claim 1, characterized in that: The mixed molten salt is a mixture of NaCl, KCl and LiF, wherein the mass ratio of NaCl, KCl and LiF is 2:3:

1.

4. The sputtering target assembly with a back plate in a vacuum environment and bonding composite solder according to claim 1, characterized in that: The slag remover in S1.4 is any one or a combination of graphite powder and borax.

5. A sputtering target assembly with a backing plate in a vacuum environment and a bonding welding process, which is realized by bonding a sputtering target assembly with a backing plate in a vacuum environment and a composite solder according to any one of claims 1 to 4, characterized in that: The specific process of the sputtering target assembly binding welding process with a back plate under the vacuum environment is as follows: S5.1: Use plasma to deeply clean the target and backing surface, with a vacuum degree of 1×10 -3 Pa, the argon flow rate was 10 sccm, the RF power was 300 W, and the cleaning time was 10 min; S5.2: Fix the cleaned target and back plate on the sandblasting equipment, and use titanium dioxide sand to sandblast the welding surface of the target and the back plate. Control the sandblasting pressure to 5~10 kg / cm², the sandblasting distance to 30~40 cm, and the sandblasting angle to 40~60°; S5.3: Use a high vacuum pump to evacuate the welding chamber to a vacuum degree of ≤10 -6 Pa, monitors and maintains stable vacuum in the welding chamber; S5.4: Place the pre-treated target and backing plate on the welding table, ensure that they are in close contact and accurately positioned, heat the welding table to 300 °C, make the composite solder begin to melt, and introduce ultrasonic vibration at the same time, maintain ultrasonic vibration and heating for 20 minutes; S5.5: Slowly cool the welding room to room temperature, perform visual inspection and X-ray flaw detection on the welding parts in turn to ensure that the welding quality meets the requirements, and perform necessary surface treatment and cleaning on the target assembly for subsequent use.

6. The bonding welding process of a sputtering target assembly with a backing plate in a vacuum environment according to claim 5, characterized in that: After the sandblasting in S5.2, the welding surface roughness Ra of the target material and the back plate reaches 0.25 μm.

7. The bonding welding process of a sputtering target assembly with a backing plate in a vacuum environment according to claim 5, characterized in that: The ultrasonic frequency in S5.4 is 7 kHz.

8. The bonding welding process of a sputtering target assembly with a backing plate in a vacuum environment according to claim 5, characterized in that: In the S5.5, the welding chamber is slowly cooled to room temperature at a rate of 2°C / min.

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