Method for recycling a backsheet

Abstract

The application provides a recycling method of a back plate, which comprises the following steps: performing gas atomization powdering on a back plate to be recycled to obtain a powder; and performing, in sequence, a sleeve assembly, degassing and hot isostatic pressing on a newly-made target blank and the powder to obtain a target assembly. Through the process combining gas atomization powdering and hot isostatic pressing, the back plate is formed at the same time as the newly-made target blank, and firm combination is formed between the back plate and the newly-made target blank, the conductivity of the prepared back plate is the same as that of a new back plate prepared by a conventional smelting process, the steps of plastic processing and heat treatment of the back plate are omitted, the material to be recycled is reused, the material utilization rate is greatly improved, and the energy consumption and the manufacturing period are significantly reduced.

Description

Technical Field

[0001] This application belongs to the field of semiconductor material preparation technology and relates to a method for recycling and reusing a backplane. Background Technology

[0002] Vacuum sputtering involves electrons accelerating towards a substrate under an electric field, colliding with argon atoms, and ionizing into a large number of argon ions and electrons. The electrons then fly towards the substrate, while the argon ions, accelerated by the electric field, bombard the target assembly, sputtering out a large number of target atoms. These neutral target atoms (or molecules) deposit on the substrate to form a film, ultimately achieving the goal of forming a film layer on the substrate surface. The target assembly consists of a target preform conforming to sputtering performance and a backplate bonded to the preform. Argon ions bombard the target material within the target assembly, while the backplate provides support and conducts heat.

[0003] Due to the sputtering principle and method, sputtering target assemblies have a low utilization rate, and discarded target assemblies still contain a large amount of expensive high-purity metal. Existing technologies typically use hydraulic press fracturing, grinding friction, or chemical acid-base dissolution to separate the backplate and target blank. Alternatively, separation can be achieved by utilizing the difference in physical properties between the target blank and backplate materials. For example, CN111748693A discloses a sputtering target recycling and processing device and method, which achieves separation by heating to melt the backplate. The problem is that it only provides a method for separating the target blank and backplate, without providing a clear solution for subsequent reuse.

[0004] CN121046793A discloses a method for preparing ruthenium target materials by recycling ruthenium residual targets. The method includes unbinding the ruthenium residual target from its corresponding backplate to separate the target from the backplate; then, after removing the weld layer metal from the ruthenium residual target, cutting it into blocks; welding the block ruthenium residual target into ruthenium electrode rods; further melting the ruthenium electrode rods into ruthenium ingots; cutting the ruthenium ingots into ruthenium target blanks; and finally, hot-pressing the ruthenium target blanks to obtain ruthenium target materials. The problem is that it only focuses on recycling the target blanks themselves, lacking methods for molding and reusing the backplate metal, which also has high added value. It is usually treated as downgraded waste, resulting in poor economic efficiency.

[0005] In summary, current industry practices for target assembly recycling primarily focus on separating the target blank from the backsheet and reusing the target blank, while neglecting the high-value reuse of the backsheet. Therefore, providing a method for recycling and reusing the backsheet is one of the pressing issues that needs to be addressed in this field. Summary of the Invention

[0006] The purpose of this application is to provide a method for recycling and reusing backing plates. By combining gas atomization powdering with hot isostatic pressing, the backing plate can be formed and firmly bonded to the newly made target blank at the same time. Moreover, the electrical conductivity of the backing plate is the same as that of the new backing plate produced by conventional melting process. This eliminates the need for separate plastic processing and heat treatment of the backing plate, realizes the reuse of the backing plate material, greatly improves the material utilization rate, and significantly reduces energy consumption and manufacturing cycle.

[0007] To achieve the purpose of this application, the following technical solution is adopted: This application provides a method for recycling and reusing a backsheet, the method comprising: The backplate to be recycled is atomized into powder to obtain powder. The newly prepared target blank and the powder are sequentially packaged, degassed, and hot isostatically pressed to obtain the target material assembly.

[0008] The recycling method provided in this application combines gas atomization powdering with hot isostatic pressing to form a strong bond between the backplate and the newly made target blank while the backplate is being formed. The electrical conductivity of the resulting backplate is the same as that of the new backplate produced by conventional smelting process. This eliminates the need for separate plastic processing and heat treatment of the backplate, enabling the reuse of the backplate material, greatly improving material utilization, and significantly reducing energy consumption and manufacturing cycle.

[0009] This application enables the backplate to regain excellent molding properties through gas atomization powdering; and achieves simultaneous sintering and interface diffusion welding of the backplate powder through hot isostatic pressing, which greatly improves the utilization rate and economic value of the backplate material.

[0010] In some embodiments, the process before atomization powdering includes: Separate the target material assembly to be recycled to obtain the back plate to be recycled and the target blank to be recycled; The backplate to be recycled is cut, cleaned and dried in sequence.

[0011] In some implementations, the separation method includes pressurization or turning.

[0012] In some embodiments, the gas atomization powdering includes: heating and melting the backplate to be recycled under vacuum or inert gas conditions to form a liquid metal stream or a liquid alloy stream, and then using high-pressure inert gas to atomize the liquid metal stream or the liquid alloy stream.

[0013] In some embodiments, the inert gas includes argon and / or nitrogen.

[0014] In some embodiments, the heating and melting temperature is higher than the liquidus line of the backsheet material to be recycled, and the difference between the two is 100℃-300℃, such as 120℃, 140℃, 150℃, 160℃, 180℃, 200℃, 220℃, 240℃, 250℃, 260℃ or 280℃.

[0015] In some embodiments, the pressure of the high-pressure inert gas is 3MPa-6MPa, for example, it can be 3.2MPa, 3.4MPa, 3.5MPa, 3.6MPa, 3.8MPa, 4MPa, 4.2MPa, 4.4MPa, 4.5MPa, 4.6MPa, 4.8MPa, 5MPa, 5.2MPa, 5.4MPa, 5.5MPa, 5.6MPa, or 5.8MPa, etc.

[0016] This application achieves both high crushing efficiency and powder quality by controlling the pressure of the high-pressure inert gas within the range of 3MPa-6MPa. This pressure range is sufficient to provide enough kinetic energy to effectively crush the molten metal or alloy into spherical powder within the target particle size range. If the pressure is too high, the powder particle size will be too fine, increasing the risk of oxidation; if the pressure is too low, the powder particle size will be too coarse and the sphericity will be poor.

[0017] In some embodiments, the particle size of the powder is 45μm-150μm, such as 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm or 140μm.

[0018] In some embodiments, the packaging assembly includes: placing the newly prepared target blank and ring, powder, isolation layer, and spacer block into the packaging in the following order; The ring is used to ensure that the powder is filled on the same plane.

[0019] By placing a ring coaxially with the newly prepared target blank, it is ensured that the powder is filled on the same plane, thus ensuring uniform shrinkage during subsequent hot isostatic pressing.

[0020] In some implementations, compaction is performed after packaging to increase the compaction density of the powder and reduce volume shrinkage during sintering.

[0021] In some embodiments, the ring is placed coaxially with the newly prepared target blank, and the two are at the same height.

[0022] In some embodiments, the outer diameter of the ring is the same as the filling diameter of the powder.

[0023] In some embodiments, the thickness of the pad is 10mm-20mm, such as 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm or 19mm.

[0024] In some embodiments, the cross-section of the pad is the same as the cross-sectional dimension of the powder filling. In some embodiments, both the sleeve and the pad are made of low-carbon steel or stainless steel.

[0025] This application ensures the uniformity of powder shrinkage in the thickness direction by controlling the thickness range of the pad and using rigid materials.

[0026] In some embodiments, the ring and the powder are made of the same material.

[0027] In some embodiments, the insulating layer is made of graphite paper and / or high-temperature cotton.

[0028] An isolation layer separates the pad from the powder to prevent sticking.

[0029] In some embodiments, the degassing temperature is 300℃-700℃, such as 350℃, 400℃, 450℃, 500℃, 550℃, 600℃ or 650℃.

[0030] In some embodiments, the degassing time is >2 hours, for example, it can be 2.2 hours, 2.5 hours, 2.8 hours, 3 hours, 3.2 hours, 3.5 hours, 3.8 hours or 4 hours.

[0031] In some embodiments, the pressure of the hot isostatic pressing is 100MPa-150MPa, for example, it can be 105MPa, 110MPa, 115MPa, 120MPa, 125MPa, 130MPa, 135MPa, 140MPa or 145MPa, etc.

[0032] In some embodiments, the temperature of the hot isostatic pressing is 0.4 to 0.8 times the solidus of the backsheet material to be recycled, for example, it can be 0.5, 0.6, or 0.7 times.

[0033] In this application, the temperature of hot isostatic pressing (HIP) is determined based on the solidus lines of different backing plate materials. The temperature range of HIP needs to be controlled. If the temperature is too high, it not only poses a significant safety hazard to the equipment, but also risks overheating of the backing plate material; if the temperature is too low, the backing plate material cannot be densified, resulting in larger internal pores and a decreased bonding rate between the target blank and the backing plate.

[0034] In some embodiments, the welding bonding rate between the freshly made target blank and the back plate in the target assembly is >99%, for example, it can be 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7% or 99.8%, etc.

[0035] The numerical range described in this application includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of brevity, this application will not exhaustively list the specific point values ​​included in the range.

[0036] Compared with the prior art, this application has the following advantages: (1) The recycling method provided in this application combines gas atomization powder making and hot isostatic pressing to form a strong bond between the back plate and the newly made target blank. The welding bonding rate between the newly made target blank and the back plate in the obtained target material assembly is >99%, and the electrical conductivity of the back plate is the same as that of the new back plate made by conventional smelting process.

[0037] (2) The recycling method provided in this application provides a process basis for high-quality hot isostatic pressing by specially designing the packaging assembly process.

[0038] (3) The recycling method provided in this application can achieve the reuse of the back plate material to be recycled without plastic processing and heat treatment, which greatly improves the material utilization rate, significantly reduces energy consumption and manufacturing cycle, and makes it easy to achieve large-scale production. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the completed packaging assembly of Embodiment 1 of this application; Among them, 1-encasing, 2-newly made target blank, 3-circular ring, 4-powder, 5-spacer block. Detailed Implementation

[0040] The technical solution of this application will be further described below with reference to the accompanying drawings and specific embodiments. However, the examples below are merely simplified examples of this application and do not represent or limit the scope of protection of this application. The scope of protection of this application shall be determined by the claims.

[0041] All materials used in the specific embodiments of this application are commercially available or prepared using conventional methods in the prior art. All methods employed are conventional techniques in this field.

[0042] Example 1 This embodiment provides a method for recycling and reusing a copper alloy backplate, the method comprising the following steps: (1) The target material assembly to be recycled is separated by turning to obtain the copper alloy back plate to be recycled and the target blank to be recycled. Then the copper alloy back plate to be recycled is cut in sequence, ultrasonically cleaned and dried using ethanol as a cleaning agent to obtain a clean copper alloy back plate to be recycled. (2) Place the copper alloy back plate to be recycled obtained in step (1) into the melting chamber of the gas atomization equipment and perform gas atomization powdering to obtain powder with a particle size of 50μm-70μm. The gas atomization powdering process includes: heating and melting the copper alloy backplate to be recycled under argon protection to form a copper alloy liquid stream, and then atomizing the copper alloy liquid stream using argon gas at a pressure of 5 MPa; the heating and melting temperature is higher than the liquidus line of the copper alloy backplate material to be recycled, and the difference between the two is 150°C. (3) The newly prepared target blank and the powder obtained in step (2) are packaged, compacted, degassed and hot isostatically pressed in sequence to obtain the target material assembly; Among them, the package configuration (such as Figure 1 As shown, the package includes: a newly prepared target blank 2, a ring 3, powder 4, an isolation layer (not shown in the figure), and a spacer block 5 arranged in the order of being placed in the sleeve 1; the ring 3 is placed coaxially with the newly prepared target blank 2 and the two are at the same height; the outer diameter of the ring 3 is the same as the filling diameter of the powder 4; the thickness of the spacer block 5 is 15mm; the cross-section of the spacer block 5 is the same as the cross-sectional dimension of the powder 4. The newly prepared target blank is made of tantalum; the sleeve and the pad are both made of stainless steel; the ring and the powder are made of the same material; the isolation layer is made of graphite paper. The degassing temperature is 500℃ and the time is 3 hours; The pressure of the hot isostatic pressing is 120 MPa; the temperature of the hot isostatic pressing is 0.6 times the solidus of the copper alloy backplate material to be recycled.

[0043] Example 2 This embodiment provides a method for recycling and reusing a copper alloy backplate, the method comprising the following steps: (1) The target material assembly to be recycled is separated by pressurization to obtain the copper alloy back plate to be recycled and the target blank to be recycled. Then the copper alloy back plate to be recycled is cut in sequence, ultrasonically cleaned and dried using acetone as a cleaning agent to obtain a clean copper alloy back plate to be recycled. (2) Place the copper alloy back plate to be recycled obtained in step (1) into the melting chamber of the gas atomization equipment and perform gas atomization powdering to obtain powder with a particle size of 80μm-100μm. The gas atomization powdering process includes: heating and melting the copper alloy backplate to be recycled under argon protection to form a copper alloy liquid stream, and then atomizing the copper alloy liquid stream using argon gas at a pressure of 6 MPa; the heating and melting temperature is higher than the liquidus line of the copper alloy backplate material to be recycled, and the difference between the two is 250°C. (3) The newly prepared target blank and the powder obtained in step (2) are packaged, compacted, degassed and hot isostatically pressed in sequence to obtain the target material assembly; The packaging assembly includes: placing the newly made target blank, ring, powder, isolation layer, and spacer block into the packaging in the following order; the ring and the newly made target blank are placed coaxially and have the same height; the outer diameter of the ring is the same as the filling diameter of the powder; the thickness of the spacer block is 12mm; the cross-section of the spacer block is the same as the cross-sectional dimension of the powder filling. The newly prepared target blank is made of tantalum; the sleeve and the pad are both made of stainless steel; the ring and the powder are made of the same material; the isolation layer is made of high-temperature cotton. The degassing temperature is 300℃ and the time is 4 hours; The pressure of the hot isostatic pressing is 150 MPa; the temperature of the hot isostatic pressing is 0.45 times the solidus of the copper alloy backplate material to be recycled.

[0044] Example 3 This embodiment provides a method for recycling and reusing a copper alloy backplate, the method comprising the following steps: (1) The target material assembly to be recycled is separated by turning to obtain the copper alloy back plate to be recycled and the target blank to be recycled. Then the copper alloy back plate to be recycled is cut in sequence, ultrasonically cleaned and dried using isopropanol as a cleaning agent to obtain a clean copper alloy back plate to be recycled. (2) Place the copper alloy back plate to be recycled obtained in step (1) into the melting chamber of the gas atomization equipment and perform gas atomization powdering to obtain powder with a particle size of 50μm-60μm. The gas atomization powdering process includes: heating and melting the copper alloy backplate to be recycled under argon protection to form a copper alloy liquid stream, and then atomizing the copper alloy liquid stream using argon gas at a pressure of 3 MPa; the heating and melting temperature is higher than the liquidus line of the copper alloy backplate material to be recycled, and the difference between the two is 100°C. (3) The newly prepared target blank and the powder obtained in step (2) are packaged, compacted, degassed and hot isostatically pressed in sequence to obtain the target material assembly; The packaging assembly includes: placing the newly made target blank, ring, powder, isolation layer, and spacer block into the packaging in the following order; the ring and the newly made target blank are placed coaxially and have the same height; the outer diameter of the ring is the same as the filling diameter of the powder; the thickness of the spacer block is 18mm; the cross-section of the spacer block is the same as the cross-sectional dimension of the powder filling. The newly prepared target blank is made of tantalum; the sleeve and the pad are both made of stainless steel; the ring and the powder are made of the same material; the isolation layer is made of high-temperature cotton. The degassing temperature is 700℃ and the time is 2.5h; The pressure of the hot isostatic pressing is 110 MPa; the temperature of the hot isostatic pressing is 0.8 times the solidus of the copper alloy backplate material to be recycled.

[0045] Example 4 This embodiment provides a method for recycling and reusing a copper alloy backplate. Except for the use of argon gas at a pressure of 1 MPa for atomization in step (2), all other conditions are the same as in embodiment 1.

[0046] Example 5 This embodiment provides a method for recycling and reusing a copper alloy backplate. Except for the use of argon gas at a pressure of 8MPa for atomization in step (2), all other conditions are the same as in embodiment 1.

[0047] Example 6 This embodiment provides a method for recycling and reusing a copper alloy backplate. Except for the absence of padding blocks in step (3) of the packaging assembly, all other conditions are the same as in embodiment 1.

[0048] Example 7 This embodiment provides a method for recycling and reusing a copper alloy backplate. Except that the pad and the powder are made of the same material in step (3), all other conditions are the same as in embodiment 1.

[0049] Example 8 This embodiment provides a method for recycling and reusing a copper alloy backplate. Except for the thickness of the pad in step (3) being 5 mm, all other conditions are the same as in embodiment 1.

[0050] Example 9 This embodiment provides a method for recycling and reusing copper alloy backplates. Except that the temperature of hot isostatic pressing in step (3) is 0.25 times the solidus line of the backplate material to be recycled, all other conditions are the same as in embodiment 1.

[0051] Comparative Example 1 This comparative example provides a method for recycling and reusing a copper alloy backplate. Except for step (2), which is adjusted to use multi-stage crushing to obtain powder with a particle size of 50μm-70μm, all other conditions are the same as in Example 1.

[0052] The welding bonding rate of the newly made target blank and the recycled copper alloy backing plate in the target material assemblies obtained in the above embodiments and comparative examples, as well as the electrical conductivity of the recycled copper alloy backing plate, were tested, and the results are shown in Table 1.

[0053] Table 1 As shown in Table 1: The recycling and reuse methods provided in Examples 1-3 of this application combine gas atomization powdering with hot isostatic pressing, along with special design of the cladding structure and control of related parameters, to achieve one-time processing of backplate forming and welding. The electrical conductivity of the recycled copper alloy backplate is the same as that of the new backplate produced by conventional smelting process, and the welding bonding rate is higher than 99%, which meets the requirements for sputtering target use.

[0054] A comparison of Examples 1 and 4-5 shows that if the gas pressure of the gas atomization powder is too low, the particle size of the powder is too coarse and the sphericity is poor, resulting in the electrical conductivity of the back plate being lower than that of the new back plate produced by the conventional smelting process, and the welding bonding rate between the target blank and the back plate decreases. If the gas pressure of the gas atomization powder is too high, the particle size of the powder is too fine, the risk of oxidation increases, resulting in the electrical conductivity of the back plate being lower than that of the new back plate produced by the conventional smelting process, and the welding bonding rate between the target blank and the back plate decreases.

[0055] A comparison of Examples 1 and 6-8 shows that if a spacer is not included in the package assembly, the uniformity of shrinkage in the thickness direction of the back plate during hot isostatic pressing cannot be ensured, resulting in a decrease in the welding bonding rate between the target blank and the back plate. If the spacer and the powder are made of the same material, the target blank and the back plate will stick together and cannot be removed. If the thickness of the spacer is too thin, the spacer will deform severely due to low support strength during sintering, resulting in inconsistent shrinkage in various places, which in turn leads to a decrease in the welding bonding rate between the target blank and the back plate.

[0056] A comparison of Examples 1 and 9 shows that if the temperature of hot isostatic pressing is too low, the backing plate material cannot be densified, the internal pores of the material are large, resulting in the electrical conductivity of the backing plate being lower than that of a new backing plate produced by conventional melting process, and the welding bonding rate between the target blank and the backing plate decreases.

[0057] A comparison of Example 1 and Comparative Example 1 shows that when multi-stage crushing is used for powder production, the physical crushing powder has a high oxygen content, poor sphericity, and low density after sintering. This results in a lower electrical conductivity of the back plate compared to the new back plate produced by conventional smelting processes, and a decrease in the welding bonding rate between the target blank and the back plate.

[0058] This application illustrates its detailed structural features through the above embodiments, but it is not limited to these detailed structural features, meaning that this application does not necessarily rely on them for implementation. Those skilled in the art should understand that any improvements to this application, equivalent substitutions of selected components, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this application.

Claims

1. A method for recycling and reusing a backplate, characterized in that, The recycling and reuse method includes: The backplate to be recycled is atomized into powder to obtain powder. The newly prepared target blank and the powder are sequentially packaged, degassed, and hot isostatically pressed to obtain the target material assembly.

2. The recycling method according to claim 1, characterized in that, The process before gas atomization powder preparation also includes: Separate the target material assembly to be recycled to obtain the back plate to be recycled and the target blank to be recycled; The backplate to be recycled is cut, cleaned and dried in sequence.

3. The recycling method according to claim 1 or 2, characterized in that, The gas atomization powder making includes: heating and melting the backplate to be recycled under vacuum or inert gas conditions to form a liquid metal stream or a liquid alloy stream, and then using high-pressure inert gas to atomize the liquid metal stream or the liquid alloy stream.

4. The recycling method according to claim 3, characterized in that, The heating and melting temperature is higher than the liquidus line of the backplate material to be recycled, and the difference between the two is 100℃-300℃; And / or, the pressure of the high-pressure inert gas is 3MPa-6MPa.

5. The recycling method according to any one of claims 1-4, characterized in that, The particle size of the powder is 45μm-150μm.

6. The recycling method according to any one of claims 1-5, characterized in that, The packaging assembly includes: placing the newly made target blank and ring, powder, isolation layer, and spacer block into the packaging in the following order; The ring is used to ensure that the powder is filled on the same plane.

7. The recycling method according to claim 6, characterized in that, The ring is placed coaxially with the newly made target blank, and the two have the same height; And / or, the outer diameter of the ring is the same as the filling diameter of the powder; And / or, the thickness of the pad is 10mm-20mm; And / or, the cross-section of the pad is the same as the cross-sectional dimension of the powder filling; And / or, the sleeve and the pad are both made of low-carbon steel or stainless steel; And / or, the ring and the powder are made of the same material; And / or, the material of the insulating layer includes graphite paper and / or high-temperature cotton.

8. The recycling method according to any one of claims 1-7, characterized in that, The degassing temperature is 300℃-700℃; And / or, the degassing time is >2h.

9. The recycling method according to any one of claims 1-8, characterized in that, The pressure of the hot isostatic pressing is 100MPa-150MPa; And / or, the temperature of the hot isostatic pressing is 0.4 to 0.8 times the solidus of the backplate material to be recycled.

10. The recycling method according to any one of claims 1-9, characterized in that, The welding bonding rate between the freshly made target blank and the back plate in the target assembly is >99%.

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