Reproducible preparation method of waste Cr target and regenerated Cr target

Abstract

The invention discloses a renewable waste Cr target preparation method and a regenerated Cr target, and belongs to the technical field of target material preparation. The method comprises the following steps: firstly, removing stains on the surface of a used waste Cr target through a grinding machine, a common lathe or numerical control, further crushing the used waste Cr target into coarse particles of 1-3 microns through a jaw crusher, then crushing the coarse particles into fine powder in a range of 60-325 meshes through a jet milling manner, mixing the fine powder with 3N-grade Cr powder with the same mesh number according to a ratio of (60-80%): (20-40%), and carrying out extrusion molding to obtain a finished product. And finally, sintering in a hot isostatic pressing manner. The density of the prepared regenerated Cr target is larger than or equal to 99%, the oxygen content is smaller than 1000 ppm, and the hardness ranges from 150 HV to 180 HV. According to the invention, the waste Cr target resource is effectively utilized, the utilization rate of the Cr target is improved, and the application cost of the Cr target in the high-tech fields of microelectronic manufacturing, optical coating and the like is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of target material preparation, and in particular relates to a method for preparing a regenerable waste Cr target and a regenerated Cr target. Background Art

[0002] Chromium (Cr) has a high melting point and good oxidation resistance, which makes the chromium target material remain stable in high temperature environment. The electron beam deposition and magnetron sputtering characteristics of chromium target materials give it unique advantages in high-tech fields such as microelectronics process and optical coating. It is widely used in high-tech fields such as optical coating, electron beam deposition, magnetron sputtering, etc. In addition, due to its high melting point and oxidation resistance, chromium targets are also widely used in solar cells, electronic equipment, decorative coatings and protective coatings.

[0003] The application of sputtering targets is based on the principle of magnetron sputtering. An orthogonal magnetic field and electric field are applied between the sputtered target and the substrate, and the target atoms on the corresponding magnetic field lines are bombarded onto the substrate surface to form a film. In order to prevent the target from being punctured and causing incomplete or uneven coating of the product, the target is usually stopped when it is not completely consumed. The sputtering utilization rate of Cr targets is less than 50%, but there is little attention and research on the recycling of waste Cr targets. Therefore, there is an urgent need for a method for preparing waste Cr targets that can be recycled to obtain recycled Cr targets. Summary of the invention

[0004] One of the purposes of the present invention is to provide a method for preparing a waste Cr target in a renewable manner, so as to solve the problem of low utilization rate of Cr target in the background technology;

[0005] The second object of the present invention is to provide a regenerated Cr target prepared by regenerating waste Cr targets, which has higher density and lower oxygen content.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] In a first aspect, a method for preparing a recyclable waste Cr target comprises the following steps:

[0008] S1. Surface treatment of waste Cr target;

[0009] S2, crushing the surface treated waste Cr target into 1-3 μm Cr coarse particles, and then crushing the Cr coarse particles into 60-325 mesh Cr fine powder;

[0010] S3, mixing the Cr fine powder with 3N grade Cr powder of the same mesh size to obtain recycled powder;

[0011] S4, loading the regenerated powder into the bag, placing the bag after molding in the furnace, and vacuuming and degassing the bag through the degassing pipe while heating;

[0012] S5. Hot isostatic pressing is performed on the degassed package, and vacuuming, pressurizing, heating sintering, cooling and pressure recovery are performed.

[0013] Furthermore, the surface treatment method in S1 includes surface machining by a grinder, a conventional lathe or a CNC lathe to remove surface stains.

[0014] Furthermore, the waste Cr target in S2 is crushed by a jaw crusher; the coarse Cr particles are crushed by a jet mill. The jet mill can effectively use high-speed airflow to accelerate the coarse Cr particles and make them collide and rub against each other, effectively control the particle size distribution, and obtain the required mesh fine powder. On the other hand, there is no mechanical grinding tool in contact with the particles during the grinding process, which will not cause wear on the particles and avoid the introduction of impurity elements.

[0015] Furthermore, in the S3, taking the total amount of the Cr fine powder and the 3N grade Cr powder as 100%, the mass percentages of the Cr fine powder and the 3N grade Cr powder are 60-80%:20-40%.

[0016] Furthermore, the heating temperature in S4 is 450-800°C;

[0017] Preferably, the heating temperature is 450-700°C.

[0018] Furthermore, in S4, the vacuum is evacuated to a vacuum degree of less than 5×10 -4 When 0.0400 ℃ and 0.0800 ℃ are reached, the heating and degassing are stopped and the degassing pipe is closed.

[0019] Furthermore, in the sintering process in S5, the heating rate is 5-7°C / min, the sintering temperature is 1000-1350°C, the sintering pressure is 100-160MPa, and the sintering time is 3-9h;

[0020] Preferably, the sintering temperature is 1050-1250° C., the sintering pressure is 130-160 MPa, and the sintering time is 4-6 h.

[0021] Furthermore, in S5, the temperature is lowered to <100° C. and the pressure is 0 MPa, meeting the furnace discharge standard.

[0022] In a second aspect, a regenerated Cr target is prepared by the above preparation method, wherein the density of the regenerated Cr target is ≥99%, the oxygen content is less than 1000 ppm, and the hardness is 150-180 HV.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention provides a method for preparing a renewable waste Cr target. The waste Cr target is ground into 60-325 mesh fine powder by two-stage crushing and grinding. During the crushing process, the oxygen content in the plasma is correlated with the nitride film of the metal chromium (such as CrN, Cr2N, CrN x O y and CrN(O2) x ), these films contain oxide components, such as Cr2O3 and CrO3; 3N grade Cr powder with the same mesh size is mixed with waste Cr fine powder, and the mixing is more uniform at the same particle size. By controlling the ratio of Cr fine powder to 3N grade Cr powder, 3N grade Cr powder is used to further improve the grain structure between waste Cr powders, and effectively reduce the oxygen content after mixing.

[0025] 2. By crushing and regenerating the waste Cr target, the regenerated Cr target prepared has the characteristics of high density, high hardness and low oxygen content, thereby effectively utilizing the waste Cr target resources, improving the utilization rate of the Cr target, and reducing the application cost of the Cr target in high-tech fields such as microelectronics manufacturing and optical coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings.

[0027] Figure 1 The waste Cr target used in the present invention;

[0028] Figure 2 It is the regenerated Cr target prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the following examples and comparative examples, 3N grade Cr powder is commercially available.

[0031] Example 1

[0032] A method for preparing a renewable waste Cr target comprises the following steps:

[0033] S1. Use a grinder, a general lathe or a CNC lathe to machine the surface of the waste Cr target to 0.2 mm and remove the stains on the surface. Figure 1 As shown;

[0034] S2, crushing the surface treated waste Cr target into 1-3 μm Cr coarse particles by a jaw crusher, and then crushing the Cr coarse particles into 100 mesh Cr fine powder by a jet mill;

[0035] S3, mixing the Cr fine powder with 3N grade Cr powder of the same mesh size (100 mesh) in a ratio of 80%:20%, and mixing the powders to obtain recycled powder;

[0036] S4, the recycled powder is loaded into the bag, and the bag with mold is placed in the furnace. Under the condition of heating temperature of 550℃, the bag is vacuumed and degassed through the degassing pipe while heating; when the vacuum degree in the bag reaches <5×10 4 After Pa, stop heating and degassing, and close the degassing pipe;

[0037] S5. Put the degassed package into a hot isostatic pressing sintering furnace to evacuate, pressurize, heat up, sinter, cool down and recover the pressure. During the sintering process, the heating rate is 6°C / min, the sintering temperature is 1250°C, the sintering pressure is 160MPa and the sintering time is 5h. After sintering, cool down and recover the pressure until the temperature is less than 100°C and the pressure in the hot isostatic pressing sintering furnace is 0MPa, which meets the furnace discharge standard. The regenerated Cr target is as follows: Figure 2 shown.

[0038] Example 2

[0039] A method for preparing a renewable waste Cr target comprises the following steps:

[0040] S1. Use a grinder, a general lathe or a CNC lathe to machine the surface of the waste Cr target to 0.2 mm and remove the stains on the surface. Figure 1 As shown;

[0041] S2. The surface treated waste Cr target is crushed into 1-3 μm Cr coarse particles by a jaw crusher, and then the Cr coarse particles are crushed into 325 mesh Cr fine powder by a jet mill;

[0042] S3, mixing the Cr fine powder with 3N grade Cr powder of the same mesh size (325 mesh) in a ratio of 60%:40%, and mixing the powders to obtain recycled powder;

[0043] S4, the recycled powder is loaded into the bag, and the bag with mold is placed in the furnace. Under the condition of heating temperature of 550℃, the bag is vacuumed and degassed through the degassing pipe while heating; when the vacuum degree in the bag reaches <5×10 -4 After Pa, stop heating and degassing, and close the degassing pipe;

[0044] S5. Place the degassed package into a hot isostatic pressing sintering furnace for vacuuming, pressurizing, heating sintering, cooling and pressure recovery. During the heating sintering process, the heating rate is 6°C / min, the sintering temperature is 1150°C, the sintering pressure is 160MPa, and the sintering time is 5h. After sintering, cool down and recover the pressure until the temperature is less than 100°C and the pressure in the hot isostatic pressing sintering furnace is 0MPa, meeting the furnace discharge standard to obtain a regenerated Cr target.

[0045] Comparative Example 1

[0046] A method for preparing a renewable waste Cr target comprises the following steps:

[0047] S1. Use a grinder, a general lathe or a CNC lathe to machine the surface of the waste Cr target to 0.2 mm and remove the stains on the surface. Figure 1 As shown;

[0048] S2. The surface treated waste Cr target is crushed into 1-3 μm Cr coarse particles by a jaw crusher, and then the Cr coarse particles are crushed into 325 mesh Cr fine powder by a jet mill;

[0049] S3, put the Cr fine powder into the bag, and place the bag with mold filling in the furnace. Under the condition of heating temperature of 550℃, vacuum and degas the bag through the degassing pipe while heating; when the vacuum degree in the bag reaches <5×10 4 After Pa, stop heating and degassing, and close the degassing pipe;

[0050] S4. Place the degassed package into a hot isostatic pressing sintering furnace for vacuuming, pressurizing, heating sintering, cooling and pressure recovery. During the heating sintering process, the heating rate is 6°C / min, the sintering temperature is 1150°C, the sintering pressure is 160MPa, and the sintering time is 5h. After sintering, cool down and recover the pressure until the temperature is less than 100°C and the pressure in the hot isostatic pressing sintering furnace is 0MPa, meeting the furnace discharge standard to obtain a regenerated Cr target.

[0051] Comparative Example 2

[0052] S1. Put 325 mesh 3N grade Cr powder into the bag, and place the bag with molded parts in the furnace. Under the condition of heating temperature of 550℃, vacuum and degas the bag through the degassing pipe while heating. When the vacuum degree in the bag reaches <5×10 -4 After Pa, stop heating and degassing, and close the degassing pipe;

[0053] S2. Place the degassed package into a hot isostatic pressing sintering furnace for vacuuming, pressurizing, heating sintering, cooling and pressure recovery. During the heating sintering process, the heating rate is 6°C / min, the sintering temperature is 1150°C, the sintering pressure is 160MPa, and the sintering time is 5h. After sintering, cool down and recover the pressure until the temperature is less than 100°C and the pressure in the hot isostatic pressing sintering furnace is 0MPa, meeting the furnace discharge standard and obtaining a Cr target.

[0054] Comparative Example 3

[0055] A method for preparing a renewable waste Cr target is different from that of Example 2 in that, in step S3, Cr fine powder is mixed with 3N grade Cr powder of the same mesh size (325 mesh) in a ratio of 50%:50% to obtain recycled powder; the remaining steps and parameters remain the same.

[0056] Comparative Example 4

[0057] A method for preparing a renewable waste Cr target is different from that of Example 1 in that, in step S3, Cr fine powder is mixed with 3N grade Cr powder of the same mesh size (100 mesh) in a ratio of 20%:80%, and the mixed powders are used to obtain recycled powder; the remaining steps and parameters remain the same.

[0058] The Cr targets prepared in Example 1 to Example 2 and Comparative Example 1 to Comparative Example 4 were tested for density, compactness, oxygen content, and hardness. The test method is as follows:

[0059] Density: Density measured by water displacement method

[0060] Density: actual density / theoretical density

[0061] Oxygen content: oxygen, nitrogen and hydrogen meter

[0062] Hardness: Vickers hardness tester

[0063] The test results are shown in Table 1.

[0064] Table 1

[0065]

[0066]

[0067] As can be seen from Table 1, compared with Example 2 and Comparative Example 1, the present invention crushes the waste Cr target into powder and mixes it with 3N grade Cr powder, which is compared with the method of crushing the waste Cr target into powder and sintering it into a single Cr target. The density and hardness are greatly improved, and the oxygen content is maintained at a low level. Compared with the performance of the single 3N grade Cr powder sintered target in Comparative Example 2, the regenerated target of Example 2 meets the requirements for reuse. By limiting the amount and mesh size of the waste Cr powder and the 3N grade Cr powder, fine and uniform grains can be obtained, so that the regenerated Cr target reaches a state close to complete density, and the effective reuse of the waste Cr powder is achieved.

[0068] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0069] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a renewable waste Cr target, characterized in that: The following steps are involved: S1. Surface treatment of waste Cr target; S2, crushing the surface treated waste Cr target into 1-3 μm Cr coarse particles, and then crushing the Cr coarse particles into 60-325 mesh Cr fine powder; S3, mixing the Cr fine powder with 3N grade Cr powder of the same mesh size to obtain recycled powder; S4, loading the regenerated powder into the bag, placing the bag after molding in the furnace, and vacuuming and degassing the bag through the degassing pipe while heating; S5. Hot isostatic pressing is performed on the degassed package, and vacuuming, pressurizing, heating sintering, cooling and pressure recovery are performed.

2. The method for preparing a renewable waste Cr target according to claim 1, characterized in that: The surface treatment method in S1 includes surface machining by a grinder, a conventional lathe or a CNC lathe.

3. The method for preparing a renewable waste Cr target according to claim 1, characterized in that: The waste Cr target in S2 is crushed by a jaw crusher; the coarse Cr particles are crushed by a jet mill.

4. The method for preparing a renewable waste Cr target according to claim 1, characterized in that: The mass percentage of the Cr fine powder and the 3N grade Cr powder in the S3 is 60-80%: 20-40%.

5. The method for preparing a renewable waste Cr target according to claim 1, characterized in that: The heating temperature in S4 is 450-800°C.

6. The method for preparing a renewable waste Cr target according to claim 1, characterized in that: The step S4 is evacuated to a vacuum degree of less than 5×10 -4 When 0.0400 ℃ and 0.0800 ℃ are reached, the heating and degassing are stopped and the degassing pipe is closed.

7. The method for preparing a renewable waste Cr target according to claim 1, characterized in that: In the sintering process in S5, the heating rate is 5-7°C / min, the sintering temperature is 1000-1350°C, the sintering pressure is 100-160MPa, and the sintering time is 3-9h.

8. The method for preparing a renewable waste Cr target according to claim 7, characterized in that: The sintering temperature is 1050-1250°C, the sintering pressure is 130-160MPa, and the sintering time is 4-6h.

9. The method for preparing a renewable waste Cr target according to claim 1, characterized in that: In S5, the temperature is lowered to <100° C. and the pressure is 0 MPa, meeting the furnace discharge standard.

10. A regenerated target material, prepared by the method for preparing the regenerable waste Cr target according to any one of claims 1 to 9, characterized in that: The density of the regenerated Cr target is ≥99%, the oxygen content is less than 1000 ppm, and the hardness is 150-180 HV.

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