A sputtering target copper plate and a preparation method thereof

Abstract

The application discloses a preparation method of a sputtering target copper plate, which comprises the following steps: sequentially performing hot rolling and warm rolling on a high-purity oxygen-free copper ingot to obtain the sputtering target copper plate; the hot rolling opening rolling temperature is 850-890 DEG C, and the total deformation is 84-87%; the warm rolling opening rolling temperature is 220-250 DEG C, and the total deformation is 40-48%. The sputtering target copper plate prepared by the preparation method has a compact internal structure, uniform grains, an average grain size of 10-30 mu m and a Vickers hardness of 80-100 HV, and the operation is simple and easy to industrialize.

Description

Technical Field

[0001] This invention belongs to the field of target preparation technology, specifically relating to a sputtering target copper plate and its preparation method. Background Technology

[0002] Magnetron sputtering is a commonly used physical vapor deposition (PVD) method with numerous advantages, including low deposition temperature, fast deposition rate, good uniformity of deposited films, and composition close to that of the target material. It can be used to prepare various materials such as metals, semiconductors, and insulators. Sputtering copper targets are mainly used in the electronics and information industries, such as integrated circuits, information storage, liquid crystal displays, laser memories, and electronic control devices. With the rapid development of new devices and materials in the microelectronics industry, and the application of electronic, magnetic, optical, optoelectronic, and superconducting thin films in high-tech and industrial fields, the market size of sputtering copper targets is expanding rapidly. To improve the sputtering efficiency of magnetron sputtering targets and ensure the quality and yield of finished films, sputtering targets are developing towards higher purity, finer grains, more uniform microstructure, and larger sizes. Strict requirements are placed on the composition, grain size and uniformity, and texture of copper targets.

[0003] Currently, the high-end ultra-high purity copper sputtering targets required by the IC industry are almost entirely monopolized by a few large multinational corporations. The domestic IC industry relies almost entirely on imports for ultra-low oxygen content pure copper sputtering targets. Based on calculations of newly added vacuum coating equipment in China over the past three years, the demand for ultra-low oxygen content pure copper plates for magnetron sputtering targets is approximately 2,000 tons per year, with processing costs ranging from 10,000 to 20,000 yuan per ton. This is not only expensive but also involves complex import procedures. Domestic target manufacturers can only produce low-grade sputtering target copper plates with lower quality and technical barriers using traditional processing methods, making it difficult to produce high-purity oxygen-free copper plates with an average grain size below 70μm and a Vickers hardness of 80-100HV. While existing technologies have undergone relevant research, numerous challenges remain, including numerous processes, complex operations, and difficulties in industrial-scale production. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a simple and industrially applicable method for preparing sputtering target copper plates, thereby producing high-purity oxygen-free copper plates with dense internal structure, uniform grains, an average grain size of less than 70 μm, and a Vickers hardness of 80–100 HV.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing a copper sputtering target, comprising the following steps:

[0007] High-purity oxygen-free copper ingots are hot-rolled and warm-rolled sequentially to obtain sputtering target copper plates.

[0008] The hot rolling start temperature is 850–890℃, and the total deformation is 84–87%.

[0009] The warm rolling temperature is 220–250°C, and the total deformation is 40–48%.

[0010] Furthermore, the purity of the high-purity oxygen-free copper ingot is above 99.995%, and the oxygen content is below 5 ppm.

[0011] Furthermore, the casting process for the high-purity oxygen-free copper ingot is as follows: the molten copper is poured into a crystallizer and cast using a vertical continuous casting device at a casting temperature of 1160–1180℃ and a casting speed of 80–120 mm / min.

[0012] Furthermore, the hot rolling passes are 7 to 8, with the processing rate of each of the first two passes being 10 to 18% and the rolling force being 100 to 200 t, and the processing rate of each of the subsequent passes being 21 to 34% and the rolling force being 350 to 450 t.

[0013] Furthermore, the warm rolling process consists of 3 to 4 passes, with a processing rate of 10 to 25% per pass, and the processing rate of each subsequent pass is less than that of the previous pass. The rolling force is 350 to 450 t.

[0014] Furthermore, the process after warm rolling also includes machining, which includes sawing, straightening, and milling.

[0015] Secondly, the present invention provides a sputtering target copper plate prepared by the above-described preparation method.

[0016] Furthermore, the average grain size of the sputtering target copper plate is 10–30 μm, and the Vickers hardness is 80–100 HV.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] The preparation method of the present invention obtains sputtering target copper plates with dense internal structure, uniform grains, average grain size of 10-30 μm and Vickers hardness of 80-100 HV through only two steps of hot rolling and warm rolling. The operation is simple and easy to industrialize. Attached Figure Description

[0019] Figure 1 Metallographic image of the copper sputtering target plate of Example 1;

[0020] Figure 2 Metallographic image of the sputtering target copper plate of Example 2;

[0021] Figure 3 Metallographic diagram of the copper plate in Comparative Example 1;

[0022] Figure 4 The image shows the metallographic structure of the copper plate in Comparative Example 2. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can more clearly understand the present invention. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention. In the embodiments of the present invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art; unless specifically specified, the technical means used are all conventional means well known to those skilled in the art.

[0024] The present invention provides a method for preparing a sputtering target copper plate, comprising the following steps:

[0025] High-purity oxygen-free copper ingots are hot-rolled and warm-rolled sequentially to obtain sputtering target copper plates.

[0026] The hot rolling start temperature is 850–890℃, and the total deformation is 84–87%.

[0027] The warm rolling temperature is 220–250°C, and the total deformation is 40–48%.

[0028] In some implementations, the purity of the high-purity oxygen-free copper ingot is above 99.995%, and the oxygen content is below 5 ppm.

[0029] In some embodiments, the casting process for high-purity oxygen-free copper ingots is as follows: molten copper is poured into a crystallizer and cast using a vertical continuous casting device at a casting temperature of 1160–1180°C and a casting speed of 80–120 mm / min.

[0030] In some embodiments, the hot rolling passes are 7 to 8, with the processing rate of the first two passes being 10 to 18% and the rolling force being 100 to 200 t, and the processing rate of the subsequent passes being 21 to 34% and the rolling force being 350 to 450 t.

[0031] In some embodiments, the warm rolling passes are 3 to 4, the processing rate of each pass is 10 to 25%, and the processing rate of the later pass is less than that of the earlier pass, and the rolling force is 350 to 450 t.

[0032] In some embodiments, the process after warm rolling also includes machining, which includes sawing, straightening, and milling.

[0033] The casting process of the high-purity oxygen-free copper ingot used in the following specific embodiments and comparative examples of the present invention is as follows: molten copper is poured into a crystallizer and cast using a vertical continuous casting device at a casting temperature of 1180℃ and a casting speed of 80mm / min. The resulting high-purity oxygen-free copper ingot has a purity of 99.996%, an oxygen content of 3.4ppm, and dimensions of 640*230*8000mm.

[0034] The following examples and comparative examples show that 230 mm thick high-purity oxygen-free copper ingots were rolled into 18 mm thick sputtering target copper plates.

[0035] Example 1

[0036] The sputtering target copper plate provided in this embodiment is prepared by the following method:

[0037] High-purity oxygen-free copper ingots are fed into a walking beam furnace and heated to 890°C, then fed into a rolling mill for hot rolling. The rolling passes are 7, and the total deformation is 86.96%. After rolling, the billet is naturally cooled to 250°C and then fed into a rolling mill for warm rolling. The rolling passes are 3, and the total deformation is 40.00%. The processing rate and rolling force of each pass in hot rolling and warm rolling are shown in Table 1. After rolling, the billet is machined, sawed, straightened, and milled to obtain sputtering target copper plates.

[0038] Table 1

[0039]

[0040] The metallographic image of the copper plate sputtering target prepared in this embodiment is shown below. Figure 1 As shown, the internal structure is dense and the grains are uniform, with an average grain size of 15μm and a maximum grain size of 60μm. The Vickers hardness is 87HV.

[0041] Example 2

[0042] The sputtering target copper plate provided in this embodiment is prepared by the following method:

[0043] High-purity oxygen-free copper ingots are fed into a walking beam furnace and heated to 850°C, then fed into a rolling mill for hot rolling. The rolling passes are 8, and the total deformation is 86.09%. After rolling, the billet is naturally cooled to 220°C and then fed into a rolling mill for warm rolling. The rolling passes are 4, and the total deformation is 43.75%. The processing rate and rolling force of each pass in hot rolling and warm rolling are shown in Table 2. After rolling, the billet is machined, sawed, straightened, and milled to obtain sputtering target copper plates.

[0044] Table 2

[0045]

[0046] The metallographic image of the copper plate sputtering target prepared in this embodiment is shown below. Figure 2As shown, the internal structure is dense and the grains are uniform, with an average grain size of 20 μm, a maximum grain size of 60 μm, and a Vickers hardness of 92 HV.

[0047] Example 3

[0048] The sputtering target copper plate provided in this embodiment is prepared by the following method:

[0049] High-purity oxygen-free copper ingots are fed into a walking beam furnace and heated to 870°C, then fed into a rolling mill for hot rolling. The rolling passes are 7, and the total deformation is 85.22%. After rolling, the billet is naturally cooled to 220°C and then fed into a rolling mill for warm rolling. The rolling passes are 4, and the total deformation is 47.06%. The processing rate and rolling force of each pass in hot rolling and warm rolling are shown in Table 3. After rolling, the billet is machined, sawed, straightened, and milled to obtain sputtering target copper plates.

[0050] Table 3

[0051]

[0052]

[0053] The sputtering target copper plate prepared in this embodiment has a dense internal structure and uniform grains, with an average grain size of 25 μm, a maximum grain size of 60 μm, and a Vickers hardness of 89 HV.

[0054] Example 4

[0055] The sputtering target copper plate provided in this embodiment is prepared by the following method:

[0056] High-purity oxygen-free copper ingots are fed into a walking beam furnace and heated to 870°C, then fed into a rolling mill for hot rolling. The rolling passes are 8, and the total deformation is 86.96%. After rolling, the billet is naturally cooled to 240°C and then fed into a rolling mill for warm rolling. The rolling passes are 3, and the total deformation is 40.00%. The processing rate and rolling force of each pass in hot rolling and warm rolling are shown in Table 4. After rolling, the billet is machined, sawed, straightened, and milled to obtain sputtering target copper plates.

[0057] Table 4

[0058]

[0059] The sputtering target copper plate prepared in this embodiment has a dense internal structure and uniform grains, with an average grain size of 30 μm, a maximum grain size of 65 μm, and a Vickers hardness of 93 HV.

[0060] Comparative Example 1

[0061] The comparative example provides a method for preparing a copper plate as follows:

[0062] High-purity oxygen-free copper ingots are fed into a walking beam furnace and heated to 890°C, then fed into a rolling mill for hot rolling. The rolling passes are 7 times, and each pass is produced uniformly according to the parabolic processing technology. The processing rate and rolling force of each pass are shown in Table 5. After rolling, the copper plates are obtained by sawing, straightening and milling.

[0063] Table 5

[0064]

[0065] Metallographic images of the copper plate sputtering target prepared in this comparative example are shown below. Figure 3 As shown, the internal structure is dense but the grains are uneven, with an average grain size of 80 μm and a maximum grain size of 120 μm. The Vickers hardness is 70 HV.

[0066] Comparative Example 2

[0067] The comparative example provides a method for preparing a copper plate as follows:

[0068] High-purity oxygen-free copper ingots are fed into a walking beam furnace and heated to 890°C, then fed into a rolling mill for hot rolling. The rolling passes are 10 times, and each pass is produced uniformly according to the parabolic processing technology. The processing rate and rolling force of each pass are shown in Table 6. After rolling, the copper plates are obtained by sawing, straightening and milling.

[0069] Table 6

[0070]

[0071]

[0072] Metallographic images of the copper plate sputtering target prepared in this comparative example are shown below. Figure 4 As shown, the internal structure is dense but the grains are uneven, with an average grain size of 80 μm and a maximum grain size of 110 μm. The Vickers hardness is 75 HV.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a sputtering target copper plate, characterized by, The method comprises the following steps: The high-purity oxygen-free copper ingot is sequentially subjected to hot rolling and warm rolling to obtain a sputtering target copper plate; The hot rolling opening rolling temperature is 850-890 DEG C, and the total deformation is 84-87%; The warm rolling opening rolling temperature is 220-250 DEG C, and the total deformation is 40-48%; The hot rolling rolling pass is 7-8 passes, the processing rate of the first two passes is 10-18% per pass, the rolling force is 100-200 t, the processing rate of the subsequent passes is 21-34% per pass, and the rolling force is 350-450 t; The warm rolling rolling pass is 3-4 passes, the processing rate is 10-25% per pass, the processing rate of the subsequent pass is less than that of the previous pass, and the rolling force is 350-450 t.

2. The method of claim 1, wherein the copper plate is prepared by a process comprising: The purity of the high-purity oxygen-free copper ingot is higher than 99.995%, and the oxygen content is less than 5 ppm. ​ 3. The method of claim 1, wherein the copper plate is prepared by a process comprising: The casting process of the high-purity oxygen-free copper ingot is as follows: the smelted copper water is poured into a crystallizer, and then cast by a vertical continuous casting device, the casting temperature is 1160-1180 DEG C, and the casting speed is 80-120 mm / min. ​ 4. The method of claim 1, wherein the copper plate is a sputtering target. The warm rolling further comprises mechanical processing, and the mechanical processing comprises sawing, straightening and milling.

5. The sputtering target copper plate prepared by the preparation method of any one of claims 1-4.

6. The sputter target copper plate according to claim 5, characterized in that The average grain size of the sputtering target copper plate is 10-30 mu m, and the Vickers hardness is 80-100 HV.

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