A cofeb target and a method for manufacturing the same

Abstract

The application provides a CoFeB target material and a preparation method thereof. The preparation method comprises the following steps: mixing CoB powder, Co powder and Fe powder to obtain mixed powder; performing ball milling on the obtained mixed powder to obtain sintered raw material; and performing hot-press sintering on the obtained sintered raw material to obtain the CoFeB target material. The preparation method provided by the application adopts a combined process of powder mixing and hot-press sintering, and high-quality CoFeB target material with high purity, high density and high magnetic permeability is prepared, the whole preparation process of the CoFeB target material is simplified, and the production cost is significantly reduced.

Description

Technical Field

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

[0002] CoFeB alloy is an important ferromagnetic alloy material widely used in spintronics, particularly in devices such as magnetic tunnel junctions (MTJs) and magnetic random access memories (MRAMs). CoFeB alloys are typically composed of cobalt (Co), iron (Fe), and boron (B). The doping of boron alters the alloy's crystal structure, disrupting the pure metallic crystal structure of Co and Fe and creating an amorphous structure. This not only eliminates long-range order but also effectively avoids the lattice mismatch problem that occurs when traditional metal alloys are combined with semiconductor materials.

[0003] Significant progress has been made in the research and application of thin film preparation technologies in the preparation of CoFeB alloys, especially techniques such as magnetron sputtering, which have provided a good platform for high-quality thin film growth. However, research and preparation methods for CoFeB alloy targets remain relatively limited.

[0004] Existing technologies disclose several studies on CoFeB target preparation techniques. For example, CN115747730A discloses a CoFeB alloy target and its preparation method, which includes weighing cobalt, iron, and boron raw materials for batching, melting them under an inert atmosphere, atomizing the melt into powder, using a boron nitride coating and molybdenum paper as spacers, pre-pressing, and then hot-pressing sintering to obtain a CoFeB alloy target with low carbon content; CN116288196A discloses a CoFeB target and its preparation method, which specifically involves melting cobalt, iron, and boron raw materials, then adding and stirring them a second time, and then casting the melt to obtain a CoFeB target; CN116815136A discloses a CoFeB alloy target and its preparation method, which involves melting boron particles, cobalt sheets, and iron sheets, atomizing them into powder to obtain alloy raw materials, and then hot isostatic pressing sintering to obtain a CoFeB alloy target. However, most of the current methods for preparing CoFeB sputtering targets rely on processes such as smelting, gas atomization powdering, and hot isostatic pressing. These processes are often complex, difficult to operate, and costly, which increases the cost of preparing high-performance CoFeB alloy sputtering targets and limits their application in large-scale industrial production.

[0005] To address the problems of existing technologies, this invention provides a process for preparing CoFeB target materials. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a CoFeB target material and its preparation method, which simplifies the preparation process, produces high-quality CoFeB target materials, and facilitates large-scale industrial production.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a CoFeB target material, the method comprising the following steps:

[0009] (1) Mix CoB powder, Co powder and Fe powder to obtain a mixed powder;

[0010] (2) The mixed powder obtained in step (1) is ball-milled to obtain sintering raw material;

[0011] (3) The sintering raw material obtained in step (2) is hot-pressed and sintered to obtain CoFeB target material.

[0012] The preparation method provided by this invention adopts a combination of powder mixing and hot pressing sintering, which simplifies the entire preparation process of CoFeB target material, reduces losses in intermediate steps, and significantly reduces production costs. It can not only ensure the high density and uniformity of CoFeB target material, but also effectively control the purity and magnetic properties of the target material, making it suitable for large-scale industrial production.

[0013] Preferably, the Fe content in the mixed powder in step (1) is 5-30 wt%, for example, it can be 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt% or 30 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] Preferably, the content of Co element in the mixed powder in step (1) is 40-70wt%, for example, it can be 40wt%, 45wt%, 50wt%, 55wt%, 60wt%, 65wt% or 70wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] Preferably, the content of element B in the mixed powder in step (1) is 5-30 wt%, for example, it can be 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt% or 30 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] Preferably, the particle size range of the CoB powder in step (1) is 5-20 μm, for example, it can be 5 μm, 10 μm, 15 μm or 20 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] Preferably, the purity of the CoB powder in step (1) is ≥3N, for example, it can be 3N, 3.5N, 4N, 4.5N, 5N or 6N, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0018] Preferably, the particle size range of the Co powder in step (1) is 3-10 μm, for example, it can be 3 μm, 4 μm, 5 μm, 6 μm, 8 μm or 10 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] Preferably, the purity of the Co powder in step (1) is ≥4N, for example, it can be 4N, 4.5N, 5N, 5.5N or 6N, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] Preferably, the particle size range of the Fe powder in step (1) is 3-10 μm, for example, it can be 3 μm, 4 μm, 5 μm, 6 μm, 8 μm or 10 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] Preferably, the Fe powder in step (1) has a purity of ≥4N, for example, it can be 4N, 4.5N, 5N, 5.5N or 6N, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] Preferably, the ball milling in step (2) is carried out in an inert gas atmosphere.

[0023] Preferably, the ball-to-material ratio in step (2) is 2:(3-10), for example, it can be 2:3, 2:4, 2:5, 2:6, 2:7, 2:8, 2:9 or 2:10, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] Preferably, the rotational speed of the ball mill in step (2) is 50-200 r / min, for example, it can be 50 r / min, 75 r / min, 100 r / min, 125 r / min, 150 r / min, 175 r / min or 200 r / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] Preferably, the ball milling time in step (2) is 10-48h, for example, it can be 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h or 48h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0026] Preferably, the hot pressing sintering temperature in step (3) is 950-1100℃, for example, it can be 950℃, 975℃, 1000℃, 1025℃, 1050℃, 1075℃ or 1100℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] Preferably, the pressure of hot pressing sintering in step (3) is 30-50 MPa, for example, it can be 30 MPa, 35 MPa, 40 MPa, 45 MPa or 50 MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Preferably, the hot pressing sintering time in step (3) is 1-3 hours, for example, it can be 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] As a preferred embodiment of the preparation method provided by the present invention, the preparation method includes the following steps:

[0030] (1) Select CoB powder with a purity of 3N or higher and a particle size range of 5-20μm, Co powder with a purity of 4N or higher and a particle size range of 3-10μm, and Fe powder with a purity of 4N or higher and a particle size range of 3-10μm, mix them to obtain a mixed powder. In the mixed powder, the content of Fe element is 5-30wt%, the content of Co element is 40-70wt%, and the content of B element is 5-30wt%.

[0031] (2) The mixed powder obtained in step (1) is ball-milled under an argon atmosphere. The ball milling speed is 50-200 r / min, the ball-to-material ratio is 2:(3-10), and the ball milling time is 10-48 h to obtain sintering raw materials.

[0032] (3) The sintering raw material obtained in step (2) is loaded into a graphite mold for hot pressing sintering. The hot pressing sintering temperature is 950-1100℃, the hot pressing sintering pressure is 30-50MPa, and the hot pressing sintering time is 1-3h to obtain CoFeB target material.

[0033] In a second aspect, the present invention provides a CoFeB target material, which is prepared by the preparation method described in the first aspect.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] The preparation method provided by this invention adopts a combination of powder mixing and hot pressing sintering process to prepare high-quality CoFeB target material with high purity, high density and high magnetic permeability, which simplifies the entire preparation process of CoFeB target material and significantly reduces production costs. Detailed Implementation

[0036] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0037] Example 1

[0038] This embodiment provides a method for preparing a CoFeB target material, the method comprising the following steps:

[0039] (1) Select CoB powder with a purity of 3N (particle size range of 5-20μm), Co powder with a purity of 4N (particle size range of 3-10μm) and Fe powder with a purity of 4N (particle size range of 3-10μm) and mix them according to the ratio of Fe element content of 15wt%, Co element content of 65wt%, and B element content of 20wt% to obtain mixed powder.

[0040] (2) The mixed powder obtained in step (1) is placed in a ball mill jar and mixed using a planetary ball mill. The ball mill speed is 100 r / min, the ball-to-material ratio is 2:6, and the time is 30 h. The mixing is carried out in an argon protective atmosphere to obtain sintering raw materials.

[0041] (3) The sintering raw material obtained in step (2) is loaded into a graphite mold for hot pressing sintering. The hot pressing sintering temperature is 1000℃, the pressure is 40MPa, and the holding time is 2h to obtain CoFeB target material.

[0042] Example 2

[0043] This embodiment provides a method for preparing a CoFeB target material, the method comprising the following steps:

[0044] (1) Select CoB powder with a purity of 3N (particle size range of 5-20μm), Co powder with a purity of 4N (particle size range of 3-10μm) and Fe powder with a purity of 4N (particle size range of 3-10μm) and mix them according to the ratio of Fe element content of 30wt%, Co element content of 40wt%, and B element content of 30wt% to obtain mixed powder.

[0045] (2) The mixed powder obtained in step (1) is placed in a ball mill jar and mixed using a planetary ball mill. The ball mill speed is 50 r / min, the ball-to-material ratio is 2:3, and the time is 48 h. The mixing is carried out in an argon protective atmosphere to obtain sintering raw materials.

[0046] (3) The sintering raw material obtained in step (2) is loaded into a graphite mold for hot pressing sintering. The hot pressing sintering temperature is 950℃, the pressure is 50MPa, and the holding time is 1h to obtain CoFeB target material.

[0047] Example 3

[0048] This embodiment provides a method for preparing a CoFeB target material, the method comprising the following steps:

[0049] (1) Select CoB powder with a purity of 3N (particle size range of 5-20μm), Co powder with a purity of 4N (particle size range of 3-10μm) and Fe powder with a purity of 4N (particle size range of 3-10μm) and mix them according to the ratio of Fe element content of 5wt%, Co element content of 70wt%, and B element content of 25wt% to obtain mixed powder.

[0050] (2) The mixed powder obtained in step (1) is placed in a ball mill jar and mixed using a planetary ball mill. The ball mill speed is 200 r / min, the ball-to-material ratio is 2:10, and the time is 10 h. The mixing is carried out in an argon protective atmosphere to obtain sintering raw materials.

[0051] (3) The sintering raw material obtained in step (2) is loaded into a graphite mold for hot pressing sintering. The hot pressing sintering temperature is 1100℃, the pressure is 30MPa, and the holding time is 3h to obtain CoFeB target material.

[0052] Example 4

[0053] This embodiment provides a method for preparing a CoFeB target material, the method comprising the following steps:

[0054] (1) Select CoB powder with a purity of 3N (particle size range of 5-20μm), Co powder with a purity of 4N (particle size range of 3-10μm) and Fe powder with a purity of 4N (particle size range of 3-10μm) and mix them according to the ratio of Fe element content of 15wt%, Co element content of 65wt%, and B element content of 20wt% to obtain mixed powder.

[0055] (2) The mixed powder obtained in step (1) is placed in a ball mill jar and mixed using a planetary ball mill. The ball mill speed is 100 r / min, the ball-to-material ratio is 2:6, and the time is 30 h. The mixing is carried out in an argon protective atmosphere to obtain sintering raw materials.

[0056] (3) The sintering raw material obtained in step (2) is loaded into a graphite mold for hot pressing sintering. The hot pressing sintering temperature is 900℃, the pressure is 40MPa, and the holding time is 2h to obtain CoFeB target material.

[0057] That is, compared with Example 1, the hot pressing sintering temperature is controlled at 900°C, and all other aspects are the same as in Example 1.

[0058] Example 5

[0059] This embodiment provides a method for preparing a CoFeB target material, the method comprising the following steps:

[0060] (1) Select CoB powder with a purity of 3N (particle size range of 5-20μm), Co powder with a purity of 4N (particle size range of 3-10μm) and Fe powder with a purity of 4N (particle size range of 3-10μm) and mix them according to the ratio of Fe element content of 15wt%, Co element content of 65wt%, and B element content of 20wt% to obtain mixed powder.

[0061] (2) The mixed powder obtained in step (1) is placed in a ball mill jar and mixed using a planetary ball mill. The ball mill speed is 100 r / min, the ball-to-material ratio is 2:6, and the time is 30 h. The mixing is carried out in an argon protective atmosphere to obtain sintering raw materials.

[0062] (3) The sintering raw material obtained in step (2) is loaded into a graphite mold for hot pressing sintering. The hot pressing sintering temperature is 1200℃, the pressure is 40MPa, and the holding time is 2h to obtain CoFeB target material.

[0063] That is, compared with Example 1, the hot pressing sintering temperature is controlled at 1200°C, and all other aspects are the same as in Example 1.

[0064] The purity, density, and permeability of the CoFeB target material prepared in the examples were tested, and the results are listed in Table 1.

[0065] Table 1

[0066] Example 1 3N5 ＞98.5 15 Example 2 3N 98 20 Example 3 3N2 ＞98.5 10 Example 4 3N5 97 10 Example 5 3N5 ＞98.5 12

[0067] As shown in Table 1, the preparation method provided by this invention uses specific raw materials and a two-step process of powder mixing and hot pressing sintering to prepare CoFeB target materials. The resulting target materials have high purity, good density, and high magnetic permeability, exhibiting excellent performance. Compared to Example 1, in Example 4, the hot pressing sintering temperature was too low, resulting in insufficient densification of the target material and a decrease in density and magnetic permeability. In Example 5, the hot pressing sintering temperature was too high, making it difficult to further improve the density of the target material, and the magnetic permeability actually decreased. This demonstrates that the specific raw materials and processes used in the preparation method of this invention are crucial to the performance of the target material.

[0068] In summary, the preparation method provided by this invention adopts a combination of powder mixing and hot pressing sintering. Using specific raw materials and proportions, high-purity, high-density, and high-magnetic-permeability high-CoFeB target materials can be prepared by hot pressing sintering after ball milling. This simplifies the entire preparation process of CoFeB target materials, significantly reduces production costs, and features a simple process with low loss and low cost.

[0069] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are 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 CoFeB target material, characterized in that, The preparation method includes the following steps: (1) Mix CoB powder with a purity of 3N or higher, Co powder with a purity of 4N or higher, and Fe powder with a purity of 4N or higher to obtain a mixed powder; (2) The mixed powder obtained in step (1) is ball-milled under an inert atmosphere to obtain sintering raw material; (3) The sintering raw material obtained in step (2) is subjected to hot pressing sintering at a temperature of 950-1100℃ and a pressure of 30-50MPa to obtain CoFeB target material. In the mixed powder of step (1), the content of Fe element is 5-30wt%, the content of Co element is 40-70wt%, and the content of B element is 5-30wt%.

2. The preparation method according to claim 1, characterized in that, The CoB powder in step (1) has a particle size range of 5-20 μm.

3. The preparation method according to claim 1, characterized in that, The particle size range of the Co powder in step (1) is 3-10 μm.

4. The preparation method according to claim 1, characterized in that, The particle size range of the Fe powder in step (1) is 3-10 μm.

5. The preparation method according to claim 1, characterized in that, The ball-to-material ratio in step (2) is 2:(3-10).

6. The preparation method according to claim 1, characterized in that, The rotation speed of the ball mill in step (2) is 50-200 r / min.

7. The preparation method according to claim 1, characterized in that, The ball milling time in step (2) is 10-48 hours.

8. The preparation method according to claim 1, characterized in that, The hot pressing sintering time in step (3) is 1-3 hours.

9. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: (1) Select CoB powder with a purity of 3N or higher and a particle size range of 5-20μm, Co powder with a purity of 4N or higher and a particle size range of 3-10μm, and Fe powder with a purity of 4N or higher and a particle size range of 3-10μm, and mix them to obtain a mixed powder. In the mixed powder, the content of Fe element is 5-30wt%, the content of Co element is 40-70wt%, and the content of B element is 5-30wt%. (2) The mixed powder obtained in step (1) is ball-milled under an argon atmosphere. The ball milling speed is 50-200 r / min, the ball-to-material ratio is 2:(3-10), and the ball milling time is 10-48 h to obtain sintering raw materials. (3) The sintering raw material obtained in step (2) is loaded into a graphite mold for hot pressing sintering. The hot pressing sintering temperature is 950-1100℃, the hot pressing sintering pressure is 30-50MPa, and the hot pressing sintering time is 1-3h to obtain CoFeB target material.

10. A CoFeB target material, characterized in that, The CoFeB target material is prepared by the preparation method according to any one of claims 1-9.