A hot isostatic pressing diffusion welding deformation correction method for a chemical vapor deposition tungsten target

Abstract

The application discloses a hot isostatic pressing diffusion welding deformation correction method of a chemical vapor deposition tungsten target, and relates to the target flattening technical field. The correction method comprises the following steps: placing the chemical vapor deposition tungsten target after diffusion welding into a specific flattening mold, the chemical vapor deposition tungsten target comprising a back plate, an intermediate layer and a tungsten plate which are sequentially arranged from bottom to top, and the tungsten plate being a columnar crystal structure prepared by using a chemical vapor deposition process; placing the flattening mold and the chemical vapor deposition tungsten target into an oven for temperature rising treatment, and keeping the temperature at a preset temperature for a preset time after the temperature rising; taking out the flattening mold and the chemical vapor deposition tungsten target, applying a preset pressure to the flattening mold for mechanical pressure treatment, and cooling to room temperature under the preset pressure condition, then taking out the chemical vapor deposition tungsten target from the flattening mold, so that the upper convex deformation variable of the tungsten plate of the corrected chemical vapor deposition tungsten target is less than or equal to 0.5 mm and no crack is generated.

Description

Technical Field

[0001] This invention relates to the field of target material leveling technology, specifically to a method for correcting deformation during hot isostatic diffusion welding of chemical vapor deposition tungsten targets. Background Technology

[0002] Tungsten, due to its excellent thermal conductivity, electrical conductivity, and high-temperature stability, is widely used in key structures such as through-holes, interconnect wires, and barrier layers in semiconductor devices. As semiconductor devices evolve towards smaller sizes and higher integration, higher demands are placed on the purity, density, and microstructure uniformity of tungsten sputtering targets. Compared to traditional powder metallurgy tungsten plates, tungsten plates prepared by chemical vapor deposition (CVD) have advantages such as high purity, high relative density, and uniform microstructure, and are increasingly used in the preparation of tungsten targets for advanced processes. However, CVD-prepared tungsten plates typically exhibit a columnar crystal structure, high hardness, and high brittleness, resulting in poor adaptability to process conditions during subsequent processing and welding.

[0003] In practical applications, tungsten sputtering targets typically employ a multi-layered composite structure consisting of a tungsten plate, an intermediate layer, and a backing plate, joined together using hot isostatic pressure diffusion welding (HIP). However, due to differences in the coefficients of thermal expansion and mechanical properties of the various layers, the sputtering target exhibits an upward convex or arc-shaped deformation after HIP welding and cooling, influenced by thermal adaptation stress. This deformation significantly affects the flatness and assembly accuracy of the target, increases the difficulty of subsequent processing, and can even impact the stability of the target during sputtering. Therefore, leveling of the tungsten sputtering target is usually required after welding.

[0004] However, existing methods for leveling post-weld targets mostly employ multiple leveling steps under pressure at room temperature. For diffusion-welded tungsten targets using chemical vapor deposition (CVD) tungsten plates, the tungsten plates have almost no plastic deformation capacity at room temperature, and direct pressure leveling easily leads to tungsten plate breakage. While multiple leveling steps can achieve shaping, they are time-consuming, energy-intensive, and prone to causing microstructural degradation and resource waste. Furthermore, existing leveling methods often use simple planar mold structures, which are difficult to adapt to the initial arc-shaped morphology of the post-weld tungsten target, resulting in limited shaping accuracy and process stability. Summary of the Invention

[0005] One objective of this invention is to provide a method for correcting deformation of chemical vapor deposition tungsten targets after hot isostatic diffusion welding, which solves the technical problem in the prior art that chemical vapor deposition tungsten targets that produce obvious arc deformation after hot isostatic diffusion welding cannot be safely and controllably leveled in a single process, while avoiding tungsten plate breakage and taking into account both shaping accuracy and process efficiency.

[0006] Another objective of this invention is to further improve the shaping accuracy and structural reliability of the shaping process.

[0007] According to the purpose of this invention, a method for correcting deformation during hot isostatic diffusion welding of chemical vapor deposition tungsten targets is provided, comprising the following steps: The chemical vapor deposition tungsten target material after diffusion welding is placed in a leveling mold. The chemical vapor deposition tungsten target material includes a back plate, an intermediate layer and a tungsten plate arranged in layers from bottom to top. The tungsten plate is prepared by chemical vapor deposition process and has a columnar crystal structure. The leveling mold and the chemical vapor deposition tungsten target are placed together in an oven for heating treatment, and then held at the preset temperature for a preset time. The heating treatment includes a first heating stage and a second heating stage. The heating rate of the first heating stage is greater than the heating rate of the second heating stage. The preset temperature is any value between 350℃ and 450℃. Remove the leveling mold and the chemical vapor deposition tungsten target, apply a preset pressure to the leveling mold for mechanical pressurization, and cool it to room temperature under the preset pressure condition; The chemical vapor deposition tungsten target is removed from the leveling mold, such that the upper convex deformation of the tungsten plate in the corrected chemical vapor deposition tungsten target is less than or equal to 0.5 mm; wherein, The leveling mold includes a detachably connected first mold and a second mold. A limiting groove for placing the tungsten target is formed between the first mold and the second mold. The first mold has an arc-shaped protrusion that bulges towards the second mold, so that the top surface of the tungsten target abuts against the arc-shaped protrusion. The height ratio of the arc-shaped protrusion of the first mold to the height of the arc-shaped structure of the tungsten target is any value between 85% and 100%. The second mold has an arc-shaped groove that is recessed towards the first mold. The recess depth of the arc-shaped groove of the second mold is equal to the height of the arc-shaped protrusion of the first mold.

[0008] Optionally, the temperature endpoint of the first heating stage is 220℃-250℃, and the heating rate is 5℃ / min-10℃ / min; the temperature endpoint of the second heating stage is the preset temperature, and the heating rate is 3℃ / min-5℃ / min.

[0009] Optionally, the preset time for heat preservation is any value between 1h and 3h.

[0010] Optionally, the ambient temperature at which the chemical vapor deposition tungsten target is cooled under the preset pressure condition is any value between 20°C and 30°C.

[0011] Optionally, the preset mechanical pressure is any value between 30T and 40T.

[0012] Optionally, the interval between the end of the heating process and the start of the mechanical pressurization process is any value between 4 min and 7 min.

[0013] Optionally, the intermediate layer is an aluminum or aluminum alloy layer, and the back plate is made of copper alloy.

[0014] This invention introduces a multi-step synergistic processing method after diffusion welding of chemical vapor deposition (CVD) tungsten targets. This method involves a specific leveling mold combined with a shaping process that includes heating, heat preservation, mechanical pressurization, and pressure-holding cooling. Under limited shaping temperature range, mold structural parameters, and mechanical pressurization conditions, the invention achieves controlled correction of the arc deformation of CVD tungsten targets after diffusion welding. This reduces the convex deformation of the tungsten plate to below 0.5 mm while avoiding brittle cracking, thereby significantly improving the flatness, structural integrity, and applicability of the CVD tungsten target for subsequent processing.

[0015] Furthermore, the second mold of the present invention is provided with an arc-shaped groove that is recessed toward the first mold, so that the chemical vapor deposition tungsten target material has a larger over-leveling space during mechanical pressurization, thereby further improving the shaping accuracy and structural reliability of the shaping process.

[0016] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0017] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic structural diagram of a hot isostatic diffusion welding deformation correction method for chemical vapor deposition tungsten targets according to an embodiment of the present invention; Figure 2 This is a schematic installation structure diagram of a chemical vapor deposition tungsten target and leveling tool according to an embodiment of the present invention; Figure 3 This is a schematic structural diagram of a calibrated chemical vapor deposition tungsten target material according to an embodiment of the present invention; Figure 4 This is a schematic structural diagram of a leveling tool according to an embodiment of the present invention; Figure 5 This is a physical image of the chemical vapor deposition tungsten target material according to Comparative Example 3 of the present invention; Figure 6 This is a physical image of the chemical vapor deposition tungsten target material according to Comparative Example 4 of the present invention; Figure 7 This is a physical image of the chemical vapor deposition tungsten target material according to Comparative Example 6 of the present invention; Figure 8 This is a physical image of the chemical vapor deposition tungsten target material according to Comparative Example 7 of the present invention; Figure 9 This is a physical image of the chemical vapor deposition tungsten target material according to Comparative Example 8 of the present invention; Figure 10 This is a curve diagram of the convex deformation-center distance according to Embodiment 1, Comparative Examples 1-2 and Comparative Example 5 of the present invention.

[0018] Figure label: 100-Chemical vapor deposition tungsten target, 10-Tungsten plate, 11-Top surface, 20-Intermediate layer, 30-Back plate, 31-Bottom surface, 200-Leveling mold, 210-First mold, 211-Arc-shaped protrusion, 220-Second mold, 221-Arc-shaped groove. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0020] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0021] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] Figure 1 This is a schematic structural diagram of a hot isostatic pressure diffusion welding deformation correction method for chemical vapor deposition tungsten targets according to an embodiment of the present invention. Figure 2 This is a schematic installation diagram of a tungsten chemical vapor deposition target and a leveling tool according to an embodiment of the present invention. Figure 3 This is a schematic structural diagram of a leveled chemical vapor deposition tungsten target according to an embodiment of the present invention. Figure 4 This is a schematic structural diagram of a leveling tool according to an embodiment of the present invention; like Figure 1 As shown, the present invention provides a method for straightening deformation caused by hot isostatic diffusion welding of a chemical vapor deposition tungsten target 100, comprising the following steps: Step S100: [The following text appears to be a separate, unrelated section:] ...as Figure 2 The diffusion-welded tungsten target 100 with the central arch is placed in the leveling mold 200. The tungsten target 100 includes a back plate 30, an intermediate layer 20 and a tungsten plate 10 arranged in layers from bottom to top. The tungsten plate 10 is prepared by chemical vapor deposition and has a columnar crystal structure. Step S200: The assembled chemical vapor deposition tungsten target 100 and leveling mold 200 are placed together in an oven for heating treatment, and then held at the preset temperature for a preset time. The heating treatment includes a first heating stage and a second heating stage. The heating rate of the first heating stage is greater than the heating rate of the second heating stage. The preset temperature is any value between 350℃ and 450℃. Step S300: Take out the leveling mold 200 and the chemical vapor deposition tungsten target 100, apply a preset pressure to the leveling mold 200 for mechanical pressurization, and cool it to room temperature under the preset pressure conditions; Step S400: Remove the chemical vapor deposition tungsten target 100 from the leveling mold 200, so that the upper convex deformation of the tungsten plate 10 in the corrected chemical vapor deposition tungsten target 100 is less than or equal to 0.5 mm.

[0024] like Figure 2 and Figure 4As shown, the leveling mold 200 includes a first mold 210 and a second mold 220 that are detachably connected. A limiting groove for placing a chemical vapor deposition tungsten target 100 is formed between the first mold 210 and the second mold 220. The first mold 210 is provided with an arc-shaped protrusion 211 that protrudes towards the second mold 220, so that the top surface 11 of the chemical vapor deposition tungsten target 100 abuts against the arc-shaped protrusion 211. The ratio of the height of the arc-shaped protrusion 211 of the first mold 210 to the height of the arc-shaped structure of the chemical vapor deposition tungsten target 100 is any value between 85% and 100%. That is, the ratio of the height of the arc-shaped protrusion 211 of the first mold 210 to the height of the arc-shaped structure of the chemical vapor deposition tungsten target 100 can be 85%, 90%, 95% or 100%, or any value between 85% and 100%. The second mold 220 has an arc-shaped recess 221 that is recessed towards the side away from the first mold 210, so that the bottom surface of the chemical vapor deposition tungsten target material abuts against the arc-shaped recess 221 during the leveling process. The depth of the arc-shaped recess 221 in the second mold 220 is equal to the height ratio of the arc-shaped protrusion 211 in the first mold. This provides sufficient over-leveling to compensate for springback and deformation during the cooling process, and avoids cracking or breakage of the tungsten plate 10 due to excessive shaping. Thus, while ensuring shaping accuracy, it improves the stability and yield of the low-temperature shaping process of the chemical vapor deposition tungsten target material 100.

[0025] like Figure 1 As shown, in this embodiment, the hot isostatic pressure diffusion welding deformation correction method for chemical vapor deposition (CVD) tungsten targets includes sequential heating, holding, mechanical pressurization, and pressure-holding cooling. The heating process involves placing the CVD tungsten target 100 into a leveling mold 200 and heating both the CVD target 100 and the leveling mold 200 to a preset temperature. The mechanical pressurization process involves holding the CVD tungsten target 100 under a preset mechanical pressure. The pressure-holding cooling process involves cooling the CVD tungsten target 100 to room temperature under the preset mechanical pressure. The preset temperature is any value between 350℃ and 450℃, and can be 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, 410℃, 420℃, 430℃, 440℃, or 450℃, or any other value between 350℃ and 450℃.

[0026] In this embodiment, before deformation correction, the chemical vapor deposition tungsten target 100 obtained by hot isostatic diffusion welding has an overall vertical cross-section with an arc-shaped structure bulging from the back plate 30 toward the tungsten plate 10 due to the difference in thermal expansion coefficients between the back plate 30, the intermediate layer 20, and the tungsten plate 10 prepared by the chemical vapor deposition process. During the correction or shaping process, the chemical vapor deposition tungsten target 100 is placed in the leveling mold 200, with one side of the tungsten plate 10 facing the first mold 210, and the top surface 11 of the tungsten plate 10 abutting against the arc-shaped protrusion 211 of the first mold 210 facing the second mold 220. At the same time, one side of the back plate 30 contacts the second mold 220, and the first mold 210 and the second mold 220 together form a limiting groove for accommodating the chemical vapor deposition tungsten target 100. Subsequently, the chemical vapor deposition tungsten target 100 and the leveling mold 200 are heated to a preset temperature range of 350℃-450℃, together with the first mold 210 and the second mold 220. After reaching the preset temperature, a preset mechanical pressure is applied to the first mold 210 and pressure holding treatment is performed. During the mechanical pressurization process, the arc-shaped protrusion 211 of the first mold 210 continuously abuts against the top surface 11 of the tungsten plate 10 under the action of external pressure and applies a downward shaping action to the tungsten plate 10. The ratio of the protrusion height of the arc-shaped protrusion 211 to the protrusion height of the original arc-shaped structure of the chemical vapor deposition tungsten target 100 is 85%-100%, thereby performing controlled over-flattening shaping of the upper arc-shaped structure of the tungsten plate 10. At the same time, the second mold 220 is always in contact with the back plate 30 and provides support for the chemical vapor deposition tungsten target 100, so that the chemical vapor deposition tungsten target 100 undergoes overall controlled deformation along the thickness direction between the first mold 210 and the second mold 220. Finally, cooling is completed under pressure, allowing the chemical vapor deposition tungsten target 100 to achieve its shape under the limiting and supporting effect of the mold. This reduces the upward convex deformation of the tungsten plate 10 in the chemical vapor deposition tungsten target 100 to less than 0.5 mm and eliminates cracks (refer to...). Figure 3 ).

[0027] In this embodiment, the temperature endpoint of the first heating stage is 220℃-250℃, and the heating rate is 5℃ / min-10℃ / min. The temperature endpoint of the second heating stage is a preset temperature, that is, any value between 350℃ and 450℃, and the heating rate is 3℃ / min-5℃ / min. The endpoint of the first heating stage can be 220℃, 230℃, 240℃, or 250℃, or any other value between 220℃ and 250℃. The heating rate of the first heating stage can be 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, or 10℃ / min, or any other value between 5℃ / min and 10℃ / min. The endpoint of the second heating stage can be 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, 410℃, 420℃, 430℃, 440℃, or 450℃, or any value between 350℃ and 450℃. The heating rate of the second heating stage can be 3℃ / min, 3.5℃ / min, 4℃ / min, 4.5℃ / min, or 5℃ / min, or any other value between 3℃ / min and 5℃ / min.

[0028] In this embodiment, the heating process is set into two stages, with the heating rate of the first stage being greater than that of the second stage. Specifically, a higher heating rate of 5°C / min to 10°C / min is used in the range of room temperature to 220°C-250°C, which shortens the overall heating time and improves the efficiency of the shaping process. When approaching the ductile-brittle transition temperature and thermal stress sensitive range of the chemical vapor deposition tungsten target 100, a lower heating rate of 3°C / min to 5°C / min is used to continue heating to the preset temperature of 350°C-450°C. This gradually reduces the temperature gradient between the tungsten plate 10, the intermediate layer 20, and the back plate 30, reducing the concentration of thermal stress caused by thermal expansion mismatch. Through the above-mentioned staged heating method, it is possible to ensure that the chemical vapor deposition tungsten target 100 is fully heated and obtains a plastic state suitable for shaping, while avoiding excessive local temperature differences, interface stress accumulation, and the risk of cracking of the tungsten plate 10 caused by rapid heating, thereby improving the stability and shaping success rate of the subsequent mechanical pressure shaping process. In this embodiment, the holding time after the heating treatment is any value between 1h and 3h. That is, the holding time of the correction process can be 1h, 1.5h, 2h, 2.5h or 3h, or any other value between 1h and 3h. This allows the leveling mold 200 and the chemical vapor deposition tungsten target 100 to reach full thermal equilibrium, reducing the temperature gradient and thermal stress concentration between the tungsten plate 10, the intermediate layer 20 and the back plate 30. This ensures that the tungsten plate 10 in the chemical vapor deposition tungsten target 100 is in a stable plastic state suitable for shaping before mechanical pressure is applied. At the same time, it avoids the increase in process cycle, energy consumption or material structure stability caused by excessively long holding time, thus taking into account shaping reliability, process efficiency and yield.

[0029] In this embodiment, by performing hot isostatic diffusion welding of the chemical vapor deposition tungsten plate 10 with the intermediate layer 20 and the back plate 30, and introducing a multi-step synergistic treatment method after welding, which involves a specific structure leveling mold 200 and the shaping process including heating treatment, mechanical pressurization treatment and pressure holding and cooling treatment, under the limited shaping temperature range, mold structure parameters and mechanical pressurization conditions, the arc deformation of the chemical vapor deposition tungsten target 100 after diffusion welding is controlled and corrected. Under the premise of avoiding brittle cracking of the tungsten plate 10, the upper convex deformation of the tungsten plate 10 is stably reduced to below 0.5 mm, thereby significantly improving the flatness, structural integrity and subsequent processing applicability of the chemical vapor deposition tungsten target 100.

[0030] In this embodiment, considering the arc-shaped structure of the vertical cross-section of the chemical vapor deposition tungsten target 100 after diffusion welding, heating treatment, heat preservation, mechanical pressurization treatment and pressure holding and cooling treatment are introduced to specifically correct the overall upward convex deformation generated after welding, forming a continuous and coordinated process of welding forming and shaping correction in the process flow.

[0031] In this embodiment, by heating the chemical vapor deposition tungsten target 100 and the leveling mold 200 together to a preset temperature range of 350℃-450℃, the chemical vapor deposition tungsten plate 10 achieves a certain degree of plasticity under conditions lower than traditional high-temperature shaping. Then, mechanical pressure is applied and held at the preset temperature, allowing the tungsten plate 10 to undergo controlled plastic deformation. This effectively reduces the risk of breakage caused by room temperature or high-temperature leveling, achieving a safe and controllable shaping effect. Furthermore, the preset temperature range of 350℃-450℃ avoids the need for high-temperature leveling. Compared to leveling at higher temperatures, this not only achieves the leveling objective but also reduces heating and holding times, thereby shortening the shaping process time, reducing energy consumption and equipment heat load, and minimizing adverse effects on the diffusion welding interface and material microstructure stability of the chemical vapor deposition tungsten target 100. This ensures shaping accuracy while improving process efficiency and overall economy.

[0032] In this embodiment, the chemical vapor deposition tungsten target 100 is integrally limited by a limiting groove formed by the detachable connection of the first mold 210 and the second mold 220, ensuring that the chemical vapor deposition tungsten target 100 remains in a stable stress state throughout the shaping process. The first mold 210 is provided with an arc-shaped protrusion 211 that faces the second mold 220, and the top surface 11 of the chemical vapor deposition tungsten target 100 abuts against the arc-shaped protrusion 211. The second mold 220 contacts the back plate 30 and provides support, thereby creating coordinated stress and overall support for the chemical vapor deposition tungsten target 100 from both the upper and lower molds during mechanical pressurization, preventing structural damage caused by localized stress concentration.

[0033] In this embodiment, by limiting the ratio of the protrusion height of the arc-shaped protrusion 211 of the first mold 210 to the protrusion height of the original arc-shaped structure of the chemical vapor deposition tungsten target 100 to 85%-100%, the over-flattening and shaping of the chemical vapor deposition tungsten target 100 is achieved during the mechanical pressurization process. This effectively compensates for the springback of the chemical vapor deposition tungsten target 100 after cooling and unloading, thereby ensuring that the upper convex deformation of the final tungsten plate 10 is stably controlled below 0.5mm, improving the consistency and repeatability of the shaping results.

[0034] In other embodiments, if the protrusion height of the first mold 210 is too large, i.e., the protrusion height is greater than 100%, it is very easy to cause a sharp increase in the over-leveling amount. Even if the tungsten plate 10 of the chemical vapor deposition tungsten target 100 has a certain plasticity under the preset temperature conditions, the excessive deformation will still cause the surface of the tungsten plate 10 to crack. If the protrusion height of the first mold 210 is less than 85%, it will result in insufficient leveling. After the leveling process is completed, the upward convexity trend of the chemical vapor deposition tungsten target 100 will be improved, but the upward convexity will still be too large, which will still have a significant impact on subsequent processing and material utilization.

[0035] In this embodiment, by coordinating the design of the temperature range of the correction process, the mold structure and the ratio of the protrusion height, the correction process can effectively suppress the generation of cracks, microcracks and weld interface damage in the tungsten plate 10 while ensuring the correction effect, thereby reducing the amount of material removal and processing risks required for subsequent machining, and thus significantly improving the yield of the chemical vapor deposition tungsten target 100 and its reliability in semiconductor sputtering applications.

[0036] In a further embodiment, the ambient temperature at which the chemical vapor deposition tungsten target 100 is cooled under a preset pressure condition is any value between 20°C and 30°C. That is, the ambient temperature for mechanical pressurization can be 20°C, 22°C, 24°C, 26°C, 28°C, or 30°C, or any other value between 20°C and 30°C. In this embodiment, the ambient temperature for mechanical pressurization is controlled within the normal temperature range of 20°C to 30°C, ensuring that the mechanical pressurization process is carried out under stable and controllable thermal conditions. This avoids introducing additional thermal stress or temperature gradient changes due to excessively high or low ambient temperatures, which could affect the uniformity of stress and shaping accuracy of the chemical vapor deposition tungsten target 100. By implementing mechanical pressurization at room temperature, it is ensured that the pressure applied by the first mold 210 is stably transmitted to the chemical vapor deposition tungsten target 100, while the second mold 220 provides reliable support to the back plate 30 side. This reduces differences in mold thermal expansion and contact state caused by ambient temperature fluctuations, which is beneficial for the precise control of the convex deformation on the tungsten plate 10.

[0037] In this embodiment, no additional environmental temperature control device is required for this ambient temperature range, and the process conditions are easy to achieve, which helps to improve the consistency, repeatability and stability of the shaping process and industrial production.

[0038] In a further embodiment, the second mold 220 is provided with an arc-shaped groove 221 recessed towards the first mold 210, so that the bottom surface 31 of the chemical vapor deposition tungsten target 100 is spaced apart from the second mold 220, thereby avoiding large-area rigid contact between the bottom surface 31 of the chemical vapor deposition tungsten target 100 and the second mold 220 during mechanical pressurization. Specifically, the arc-shaped groove 221 in the second mold 220 ensures that the external pressure is mainly applied to the tungsten plate 10 side by the arc-shaped protrusion 211 of the first mold 210, and transmitted through the overall elastic-plastic deformation of the chemical vapor deposition tungsten target 100, while the second mold 220 mainly functions as a limiter and support, reducing the localized concentrated stress on the back plate 30 side and reducing the risk of secondary deformation or structural damage to the back plate 30 and the intermediate layer 20. Meanwhile, the arc-shaped groove 221 provides the necessary release space for the springback and deformation adjustment of the chemical vapor deposition tungsten target 100 during the shaping process, which is conducive to the controlled correction of the arc-shaped structure of the tungsten plate 10, thereby further improving the shaping accuracy and structural reliability of the correction process.

[0039] In a further embodiment, the preset mechanical pressure is any value between 30T and 40T, that is, the preset mechanical pressure can be 30T, 32T, 34T, 36T, 38T or 40T, or any other value between 30T and 40T. In this embodiment, the preset mechanical pressure in the shaping process is controlled within the range of 30T-40T, so that the shaping load applied to the chemical vapor deposition tungsten target 100 matches its elastic-plastic deformation characteristics under preset temperature conditions. This not only overcomes the residual stress inside the chemical vapor deposition tungsten target 100 after hot isostatic pressing and the arc-shaped springback tendency of the tungsten plate 10, but also allows the tungsten plate 10 to undergo sufficient and controllable plastic shaping under the action of the arc-shaped protrusion 211 of the first mold 210, thereby effectively reducing the upper convex deformation of the tungsten plate 10 and stabilizing it within 0.5mm. Furthermore, it can also avoid cracking of the tungsten plate 10, interlayer peeling, or damage to the intermediate layer 20 and the backing plate 30 caused by excessive mechanical pressure. That is, while ensuring the shaping effect, it also takes into account the overall structural integrity of the chemical vapor deposition tungsten target 100 and the consistency of repeated processing, thereby improving the reliability of the shaping process and the stability of the process window.

[0040] In a further embodiment, the interval between the heating treatment and the mechanical pressurization treatment is any value between 4 min and 7 min. The interval can be 4 min, 5 min, 6 min, or 7 min, or any other value between 4 min and 7 min. In this embodiment, controlling the interval between the heating treatment and the mechanical pressurization treatment within the range of 4 min to 7 min allows the chemical vapor deposition tungsten target 100 sufficient time for temperature conduction and structural thermal equilibrium after heating. This promotes a more uniform temperature distribution among the tungsten plate 10, the intermediate layer 20, and the back plate 30, and avoids non-uniform plastic deformation or new thermal stress concentration caused by excessive local temperature differences in the initial stage of mechanical pressurization. In addition, the aforementioned interval time can further release the residual stress introduced during hot isostatic pressing and heating, making it easier for the chemical vapor deposition tungsten target 100 to undergo stable and controllable shaping deformation in the subsequent mechanical pressing stage. This effectively reduces springback and deformation fluctuations during the shaping process, improves the consistency of the shaping process and the flatness control accuracy of the finished chemical vapor deposition tungsten target 100.

[0041] In a further embodiment, the intermediate layer 20 is made of aluminum or an aluminum alloy, and the back plate 30 is made of copper alloy. By introducing an aluminum intermediate layer 20 with good plasticity and thermal conductivity between the tungsten plate 10 and the back plate 30, the difference in thermal expansion coefficient and elastic modulus between the tungsten plate 10 and the copper alloy back plate 30 can be effectively mitigated. This allows the aluminum intermediate layer to play a stress transition and buffering role during hot isostatic pressing diffusion welding and subsequent cooling, reducing the risk of interfacial thermal stress concentration and interlayer cracking. Simultaneously, the aluminum or aluminum alloy layer has high atomic diffusion activity under hot isostatic pressing conditions, which is beneficial for forming stable metallurgical bonds with the tungsten plate 10 and the copper alloy back plate 30, respectively, thereby improving the overall bonding strength of the multilayer structure.

[0042] The technical solution of this application will be further described below with reference to specific embodiments.

[0043] Example 1

[0044] In the hot isostatic pressure diffusion welding deformation correction method for chemical vapor deposition tungsten target 100, the deformed chemical vapor deposition tungsten target 100 is first placed in a leveling mold 200 and heated together to 250°C at a heating rate of 10°C / min, then to 330°C at a heating rate of 5°C / min, and held at that temperature for 1 hour. Then, the leveling mold 200 and the chemical vapor deposition tungsten target 100 are quickly removed from the oven together, and the leveling mold 200 is removed within 3 minutes. The tungsten target 100 and the chemical vapor deposition target 200 are placed together in a hydraulic press, and a vertical force of 40T is applied to the leveling mold 200. After the temperature drops below 300℃, the tungsten target 100 and the leveling mold 200 are heated together to 330℃ and then quickly removed from the oven. Within 3 minutes, the leveling mold 200 and the tungsten target 100 are placed together in a hydraulic press, and a vertical force of 40T is applied to the leveling mold 200. The pressure is maintained while the material is cooled to room temperature to obtain the corrected tungsten target 100.

[0045] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that the ratio of the protrusion height of the first mold 210 to that of the chemical vapor deposition tungsten target 100 is 60%.

[0046] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that the ratio of the protrusion height of the first mold 210 to that of the chemical vapor deposition tungsten target 100 is 75%.

[0047] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that the ratio of the protrusion height of the first mold 210 to that of the chemical vapor deposition tungsten target 100 is 115%.

[0048] Comparative Example 4 The only difference between Comparative Example 4 and Example 1 is that, before applying a preset temperature to the leveling mold 200 and the chemical vapor deposition tungsten target 100, a pre-pressure of 30T is applied to the chemical vapor deposition tungsten target 100 through the leveling mold 200.

[0049] Comparative Example 5 The only difference between Comparative Example 5 and Example 1 is that the preset mechanical pressure is 25T.

[0050] Comparative Example 6 The only difference between Comparative Example 6 and Example 1 is that the preset mechanical pressure is 50T.

[0051] Comparative Example 7 The only difference between Comparative Example 7 and Example 1 is that the chemical vapor deposition tungsten target 100 after mechanical pressurization is cooled under pressureless conditions.

[0052] Comparative Example 8 The only difference between Comparative Example 8 and Example 1 is that the chemical vapor deposition tungsten target 100 after mechanical pressurization treatment at a preset temperature of 300°C is cooled under pressureless conditions.

[0053] Figure 5 This is a physical image of the chemical vapor deposition tungsten target 100 according to Comparative Example 3 of the present invention. Figure 6 This is a physical image of the chemical vapor deposition tungsten target 100 according to Comparative Example 4 of the present invention. Figure 7 This is a physical image of the chemical vapor deposition tungsten target 100 according to Comparative Example 6 of the present invention. Figure 8 This is a physical image of the chemical vapor deposition tungsten target 100 according to Comparative Example 7 of the present invention. Figure 9 This is a physical image of the chemical vapor deposition tungsten target 100 according to Comparative Example 8 of the present invention. Figure 10 This is a curve diagram of the convex deformation-center distance according to Embodiment 1, Comparative Examples 1-2 and Comparative Example 5 of the present invention.

[0054] The bulge deformation of the chemical vapor deposition tungsten target 100 prepared in Example 1 and Comparative Examples 1-8 was measured and the cracks in the tungsten plate 10 were detected, as shown in Table 1 and Table 2. Figures 5 to 10 The test results are shown.

[0055] Table 1. Measurement of protrusion deformation of tungsten targets prepared in Example 1 and Comparative Examples 1-8

[0056] As shown in Table 1, Figures 5 to 10 As shown, the tungsten target 100 prepared in Example 1 has a protrusion deformation of significantly less than 0.5 mm, and the surface of the tungsten target 100 is free of cracks or fissures. In contrast, the tungsten target 100 prepared in Comparative Examples 1-8 typically has a protrusion deformation greater than 0.5 mm or exhibits obvious cracks or fissures on its surface. The results indicate that the shaping process in Example 1, which sequentially involves heating, mechanical pressurizing, and cooling the tungsten target 100, can mechanically level the protruding deformation portion of the tungsten target 100, ensuring that the upper protrusion deformation of the tungsten plate 10 is less than or equal to 0.5 mm while preventing the tungsten target 100 from breaking or cracking. Figure 10 The initial chemical vapor deposition tungsten target 100 in the text is the chemical vapor deposition tungsten target 100 after diffusion welding.

[0057] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0058] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for correcting deformation during hot isostatic diffusion welding of chemical vapor deposition tungsten targets, characterized in that, Includes the following steps: The chemical vapor deposition tungsten target material after diffusion welding is placed in a leveling mold. The chemical vapor deposition tungsten target material includes a back plate, an intermediate layer and a tungsten plate arranged in layers from bottom to top. The tungsten plate is prepared by chemical vapor deposition process and has a columnar crystal structure. The leveling mold and the chemical vapor deposition tungsten target are placed together in an oven for heating treatment, and then held at the preset temperature for a preset time. The heating treatment includes a first heating stage and a second heating stage. The heating rate of the first heating stage is greater than the heating rate of the second heating stage. The preset temperature is any value between 350℃ and 450℃. Remove the leveling mold and the chemical vapor deposition tungsten target, apply a preset pressure to the leveling mold for mechanical pressurization, and cool it to room temperature under the preset pressure condition; The chemical vapor deposition tungsten target is removed from the leveling mold, such that the upper convex deformation of the tungsten plate in the corrected chemical vapor deposition tungsten target is less than or equal to 0.5 mm; wherein, The leveling mold includes a first mold and a second mold that are detachably connected. A limiting groove for placing the chemical vapor deposition tungsten target is formed between the first mold and the second mold. The first mold has an arc-shaped protrusion that protrudes towards the second mold, so that the top surface of the chemical vapor deposition tungsten target abuts against the arc-shaped protrusion. The ratio of the height of the arc-shaped protrusion of the first mold to the height of the arc-shaped structure of the chemical vapor deposition tungsten target is any value between 85% and 100%. The second mold has an arc-shaped groove that is recessed towards the side away from the first mold. The recess depth of the arc-shaped groove of the second mold is equal to the height of the arc-shaped protrusion of the first mold.

2. The method for correcting deformation during hot isostatic diffusion welding of chemical vapor deposition tungsten targets according to claim 1, characterized in that, The temperature endpoint of the first heating stage is 220℃-250℃, and the heating rate is 5℃ / min-10℃ / min. The temperature endpoint of the second heating stage is the preset temperature, and the heating rate is 3℃ / min-5℃ / min.

3. The method for correcting deformation during hot isostatic diffusion welding of chemical vapor deposition tungsten targets according to claim 1, characterized in that, The preset time for heat preservation is any value between 1h and 3h.

4. The method for correcting deformation during hot isostatic diffusion welding of chemical vapor deposition tungsten targets according to claim 1, characterized in that, The ambient temperature at which the chemical vapor deposition tungsten target is cooled under the preset pressure conditions is any value between 20℃ and 30℃.

5. The method for correcting deformation during hot isostatic diffusion welding of chemical vapor deposition tungsten targets according to claim 1, characterized in that, The preset mechanical pressure is any value between 30T and 40T.

6. The method for correcting deformation during hot isostatic diffusion welding of chemical vapor deposition tungsten targets according to claim 1, characterized in that, The interval between the end of the heating process and the start of the mechanical pressurization process is any value between 4 min and 7 min.

7. The method for correcting deformation during hot isostatic diffusion welding of chemical vapor deposition tungsten targets according to any one of claims 1-6, characterized in that, The intermediate layer is an aluminum or aluminum alloy layer, and the back plate is a copper alloy.

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