Preparation method of MoTi alloy target material

Abstract

The invention provides a preparation method of a MoTi alloy target material, which comprises the following steps: mixing molybdenum powder and titanium powder to obtain mixed powder; then the mixed powder is subjected to cold isostatic pressing, and a molybdenum-titanium green body is obtained; and then the molybdenum-titanium green body is subjected to vacuum sintering, and the MoTi alloy target material is obtained. The preparation method provided by the invention does not need hot isostatic pressing, and has relatively high efficiency and relatively low cost; and moreover, through the combination of cold isostatic pressing and vacuum sintering, the sintering temperature can be increased, so that the MoTi alloy target material with relatively high density can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of sputtering target materials and relates to a method for preparing an alloy target material, in particular to a method for preparing a MoTi alloy target material. Background Art

[0002] Thin films sputtered from Mo targets are widely used in the electronic information industry due to their good electrical conductivity and extremely stable chemical properties. They are especially used in the display field and are usually used as diffusion barriers in wiring. However, pure Mo target films have insufficient adhesion. Studies have shown that adding a certain amount of Ti elements to Mo can effectively improve this defect, making its various properties such as adhesion more balanced.

[0003] Molybdenum-titanium alloy (MT) refers to an alloy formed by molybdenum and titanium in a certain proportion. Molybdenum-titanium alloy not only maintains the good electrical and thermal conductivity of molybdenum, but also has relatively balanced etching performance and good adhesion after being sputtered into a thin film. Molybdenum-titanium alloy is usually prepared by powder metallurgy, and sintering is a very important link. The sintering process has a great influence on the density, grain size, uniformity of element distribution, etc. of the alloy. During the sintering process, sintering temperature, time, etc. are the main process parameters, which have a very important influence on the density, organizational structure and mechanical properties of the alloy.

[0004] The existing preparation processes of MoTi alloy mainly include smelting method and powder metallurgy method. Due to the large difference between the melting points of Mo and Ti and the high melting point of Mo at 2620°C, the smelting energy consumption is large and severe segregation will occur. Therefore, smelting is less popularized and generally powder metallurgy is the main method. MoTi powder metallurgy is mainly divided into three types: vacuum sintering, hot pressing sintering and hot isostatic pressing sintering. Since MoTi sputtering is now mainly based on the 8.5 generation line, the target size requirements are relatively large. It is difficult to directly burn out a target of such size by hot pressing sintering, and the cost of hot isostatic pressing is high. When the conventional powder is mixed and then vacuum sintered, the temperature is generally below the melting point of Ti. The MoTi target sintered at such a temperature is difficult to meet the density requirements.

[0005] MoTi alloy is widely used in powder metallurgy due to the large difference in melting points between Mo and Ti elements. Its conventional preparation process is powder mixing, pressing, sintering and subsequent processing. For example, CN116288190A discloses a low-oxygen, high-density, high-plasticity molybdenum-titanium alloy target and preparation method, including: taking a set amount of molybdenum powder and titanium powder, mixing them in a mixer under argon protection to obtain a mixed powder; cold isostatic pressing the mixed powder to obtain a molybdenum-titanium green body; low-temperature vacuum sintering the molybdenum-titanium green body to obtain a pre-sintered body; hot isostatic pressing the pre-sintered body to obtain a low-oxygen, high-density, high-plasticity molybdenum-titanium alloy target.

[0006] However, this method requires hot isostatic pressing treatment with high energy consumption and complex process, which is not conducive to industrial promotion. Therefore, it is necessary to provide a low-cost preparation method that can prepare MoTi alloy targets with uniform element distribution and high density. Summary of the invention

[0007] In view of the shortcomings of the prior art, the object of the present invention is to provide a method for preparing a MoTi alloy target, which does not require hot isostatic pressing, has high efficiency and low cost; and can increase the sintering temperature, thereby obtaining a MoTi alloy target with high density and uniform element distribution.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for preparing a MoTi alloy target, the preparation method comprising the following steps:

[0010] Molybdenum powder and titanium powder are mixed to obtain mixed powder; the mixed powder is then cold isostatically pressed to obtain a molybdenum-titanium green body; and the molybdenum-titanium green body is vacuum sintered to obtain the MoTi alloy target.

[0011] The preparation method provided by the present invention does not require hot isostatic pressing, and has high efficiency and low cost. Moreover, the present invention mixes molybdenum powder and titanium powder to make the elements evenly distributed. Since the mixed powder has a small specific surface area and a large activation energy, it can also have a higher density at the same sintering temperature. In addition, the present invention combines cold isostatic pressing with vacuum sintering to increase the sintering temperature, thereby obtaining a MoTi alloy target with a higher density.

[0012] Preferably, the molybdenum powder has a Fisher particle size of 2-6 μm.

[0013] Preferably, the purity of the molybdenum powder is 3N or above.

[0014] Preferably, the titanium powder has a Fisher particle size of 33-36 μm.

[0015] Preferably, the purity of the titanium powder is 3N or above.

[0016] Preferably, the mixing method is ball milling.

[0017] Preferably, the rotation speed of the ball mill is 350-450 r / min.

[0018] Preferably, the ball milling time is 8-16 hours.

[0019] Preferably, the ball-to-material ratio of the ball mill is 1:(4-6).

[0020] Preferably, the ball milling is performed in a protective atmosphere.

[0021] Preferably, the gas used for the protective atmosphere includes nitrogen and / or an inert gas.

[0022] Preferably, the cold isostatic pressing pressure is 200-300 MPa.

[0023] Preferably, the cold isostatic pressing time is 5-40 min.

[0024] Preferably, the vacuum sintering includes a first sintering and a second sintering performed sequentially.

[0025] Preferably, the first sintering is performed at a temperature of 700-1000° C. and for a time of 1-3 hours.

[0026] Preferably, the second sintering temperature is 1400-1600° C., and the temperature is maintained for 3-6 hours.

[0027] Preferably, the vacuum degree of the vacuum sintering is less than or equal to 1×10 -2 Pa.

[0028] As a preferred technical solution of the present invention, the preparation method comprises:

[0029] (1) In a protective atmosphere, ball milling is performed to mix molybdenum powder having a Fischer-Tropsch particle size of 2-6 μm and titanium powder having a Fischer-Tropsch particle size of 33-36 μm to obtain a mixed powder;

[0030] The purity of the molybdenum powder is 3N or more;

[0031] The purity of the titanium powder is 3N or above;

[0032] The ball milling speed is 350-450r / min, the time is 8-16h, and the ball-to-material ratio is 1:(4-6);

[0033] (2) cold isostatically pressing the mixed powder under a pressure of 200-300 MPa for 5-40 min to obtain a molybdenum-titanium green body;

[0034] (3) Vacuum degree is less than or equal to 1×10 -2 Pa, vacuum sintering the molybdenum-titanium green body to obtain the MoTi alloy target;

[0035] The vacuum sintering includes a first sintering and a second sintering performed sequentially;

[0036] The first sintering temperature is 700-1000°C and the time is 1-3h;

[0037] The second sintering temperature is 1400-1600° C. and the temperature is kept for 3-6 hours.

[0038] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The preparation method provided by the present invention does not require hot isostatic pressing, and has high efficiency and low cost. Moreover, the present invention mixes molybdenum powder and titanium powder to make the elements evenly distributed. Since the mixed powder has a small specific surface area and a large activation energy, it can also have a higher density at the same sintering temperature. In addition, the present invention combines cold isostatic pressing with vacuum sintering to increase the sintering temperature, thereby obtaining a MoTi alloy target with a higher density. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0042] A certain embodiment of the present invention provides a method for preparing a MoTi alloy target, the preparation method comprising the following steps:

[0043] Molybdenum powder and titanium powder are mixed to obtain mixed powder; the mixed powder is then cold isostatically pressed to obtain a molybdenum-titanium green body; and the molybdenum-titanium green body is vacuum sintered to obtain the MoTi alloy target.

[0044] The preparation method provided by the present invention does not require hot isostatic pressing, and has high efficiency and low cost. Moreover, the present invention mixes molybdenum powder and titanium powder to make the elements evenly distributed. Since the mixed powder has a small specific surface area and a large activation energy, it can also have a higher density at the same sintering temperature. In addition, the present invention combines cold isostatic pressing with vacuum sintering to increase the sintering temperature, thereby obtaining a MoTi alloy target with a higher density.

[0045] In some embodiments, the molybdenum powder has a Fisher particle size of 2-6 μm, such as 2 μm, 3 μm, 4 μm, 5 μm or 6 μm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0046] In some embodiments, the purity of the molybdenum powder is above 3N, for example, it can be 99.90wt%, 99.93wt%, 99.95wt%, 99.98wt% or 99.99wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] In some embodiments, the titanium powder has a Fisher particle size of 33-36 μm, for example, 33 μm, 34 μm, 35 μm or 36 μm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0048] In some embodiments, the purity of the titanium powder is above 3N, for example, it can be 99.90wt%, 99.93wt%, 99.95wt%, 99.98wt% or 99.99wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0049] In the present invention, the molybdenum powder and the titanium powder are mixed according to an atomic ratio of 1:1.

[0050] In certain embodiments, the mixing method is ball milling.

[0051] In some embodiments, the ball mill has a rotation speed of 350-450 r / min, for example, 350 r / min, 380 r / min, 400 r / min, 420 r / min or 450 r / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0052] In some embodiments, the ball milling time is 8-16 hours, for example, 8 hours, 10 hours, 12 hours, 15 hours or 16 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] In some embodiments, the ball-to-material ratio of the ball mill is 1:(4-6), for example, 1:4, 1:5 or 1:6, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0054] In the present invention, the grinding balls used in the ball mill are molybdenum balls.

[0055] In certain embodiments, the ball milling is performed in a protective atmosphere.

[0056] In some embodiments, the protective atmosphere includes nitrogen and / or an inert gas.

[0057] The inert gas includes any one of helium, neon or argon or a combination of at least two of them. Typical but non-limiting combinations include a combination of helium and neon, a combination of neon and argon, a combination of helium and argon, or a combination of helium, neon and argon.

[0058] When the cold isostatic pressing is performed, the mixed powder is loaded into the cold isostatic pressing mold, and the mixed powder is compacted to ensure that the thickness in each direction is within the same horizontal range.

[0059] In some embodiments, the cold isostatic pressing pressure is 200-300 MPa, for example, 200 MPa, 240 MPa, 250 MPa, 280 MPa or 300 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0060] In some embodiments, the cold isostatic pressing time is 5-40 min, for example, 5 min, 10 min, 20 min, 30 min or 40 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0061] In some embodiments, the vacuum sintering includes a first sintering and a second sintering performed sequentially.

[0062] The present invention reduces the oxygen content and impurity content in the molybdenum-titanium green body by sequentially performing the first sintering and the second sintering.

[0063] In some embodiments, the first sintering is performed at a temperature of 700-1000° C. and for a time of 1-3 hours.

[0064] The first sintering temperature is 700-1000°C, for example, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C or 1000°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0065] The first sintering time is 1-3 hours, for example, 1 hour, 2 hours or 3 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0066] In some embodiments, the second sintering is performed at a temperature of 1400-1600° C. and for a time of 3-6 hours.

[0067] The temperature of the second sintering is 1400-1600° C., for example, 1400° C., 1450° C., 1500° C., 1550° C. or 1600° C., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0068] The second sintering time is 3-6 hours, for example, 3 hours, 4 hours, 5 hours or 6 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0069] In some embodiments, the vacuum degree of the vacuum sintering is less than or equal to 1×10 -2 Pa.

[0070] In certain embodiments, the preparation method provided by the present invention comprises:

[0071] (1) In a protective atmosphere, ball milling is performed to mix molybdenum powder having a Fischer-Tropsch particle size of 2-6 μm and titanium powder having a Fischer-Tropsch particle size of 33-36 μm to obtain a mixed powder;

[0072] The purity of the molybdenum powder is 3N or more;

[0073] The purity of the titanium powder is 3N or above;

[0074] The ball milling speed is 350-450r / min, the time is 8-16h, and the ball-to-material ratio is 1:(4-6);

[0075] (2) cold isostatically pressing the mixed powder under a pressure of 200-300 MPa for 5-40 min to obtain a molybdenum-titanium green body;

[0076] (3) Vacuum degree is less than or equal to 1×10 -2 Pa, vacuum sintering the molybdenum-titanium green body to obtain the MoTi alloy target;

[0077] The vacuum sintering includes a first sintering and a second sintering performed sequentially;

[0078] The first sintering temperature is 700-1000°C and the time is 1-3h;

[0079] The second sintering is carried out at a temperature of 1400-1600° C. and for a time of 3-6 hours.

[0080] In order to clearly illustrate the technical solution of the present invention, in a specific implementation manner of the present invention, the purity of the molybdenum powder is 3N, and the purity of the titanium powder is 3N.

[0081] Example 1

[0082] This embodiment provides a method for preparing a MoTi alloy target, and the preparation method comprises the following steps:

[0083] (1) in a nitrogen atmosphere, ball milling and mixing molybdenum powder with a Fischer-Tropsch particle size of 4 μm and titanium powder with a Fischer-Tropsch particle size of 35 μm to obtain a mixed powder;

[0084] The molybdenum powder and the titanium powder are mixed in an atomic ratio of 1:1;

[0085] The ball milling speed is 400 r / min, the time is 12 h, and the ball-to-material ratio is 1:5;

[0086] The grinding balls used in the ball milling are molybdenum balls;

[0087] (2) the mixed powder is loaded into a cold isostatic pressing mold, compacted to ensure that the thickness in each direction is within the same horizontal range, and then cold isostatically pressed for 20 minutes under a pressure of 250 MPa to obtain a molybdenum-titanium green body;

[0088] (3) Vacuum degree 1×10 -2 Pa, vacuum sintering the molybdenum-titanium green body to obtain the MoTi alloy target;

[0089] The vacuum sintering includes a first sintering and a second sintering performed sequentially;

[0090] The first sintering temperature is 800°C and the time is 2h;

[0091] The second sintering process is performed at a temperature of 1500° C. and for a time of 4 hours.

[0092] Example 2

[0093] This embodiment provides a method for preparing a MoTi alloy target, and the preparation method comprises the following steps:

[0094] (1) in a nitrogen atmosphere, ball milling and mixing molybdenum powder with a Fischer-Tropsch particle size of 2 μm and titanium powder with a Fischer-Tropsch particle size of 33 μm to obtain a mixed powder;

[0095] The ball milling speed is 350r / min, the time is 16h, and the ball-to-material ratio is 1:4;

[0096] The grinding balls used in the ball milling are molybdenum balls;

[0097] (2) the mixed powder is loaded into a cold isostatic pressing mold, compacted to ensure that the thickness in each direction is within the same horizontal range, and then cold isostatically pressed for 40 minutes under a pressure of 200 MPa to obtain a molybdenum-titanium green body;

[0098] (3) Vacuum degree 1×10 -2 Pa, vacuum sintering the molybdenum-titanium green body to obtain the MoTi alloy target;

[0099] The vacuum sintering includes a first sintering and a second sintering performed sequentially;

[0100] The first sintering temperature is 700°C and the time is 3h;

[0101] The second sintering process was performed at a temperature of 1400° C. and for a time of 6 hours.

[0102] Example 3

[0103] This embodiment provides a method for preparing a MoTi alloy target, and the preparation method comprises the following steps:

[0104] (1) in a nitrogen atmosphere, ball milling and mixing molybdenum powder with a Fischer-Tropsch particle size of 6 μm and titanium powder with a Fischer-Tropsch particle size of 36 μm to obtain a mixed powder;

[0105] The ball milling speed is 450r / min, the time is 8h, and the ball-to-material ratio is 1:6;

[0106] The grinding balls used in the ball milling are molybdenum balls;

[0107] (2) the mixed powder is loaded into a cold isostatic pressing mold, compacted to ensure that the thickness in each direction is within the same horizontal range, and then cold isostatically pressed for 5 minutes under a pressure of 300 MPa to obtain a molybdenum-titanium green body;

[0108] (3) Vacuum degree 1×10 -2 Pa, vacuum sintering the molybdenum-titanium green body to obtain the MoTi alloy target;

[0109] The vacuum sintering includes a first sintering and a second sintering performed sequentially;

[0110] The first sintering temperature is 1000°C and the time is 1h;

[0111] The second sintering temperature is 1600° C. and the time is 3 hours.

[0112] Example 4

[0113] This embodiment provides a method for preparing a MoTi alloy target, which is the same as that of Embodiment 1 except that the temperature of the second sintering is 1400°C.

[0114] Example 5

[0115] This embodiment provides a method for preparing a MoTi alloy target, which is the same as that of Embodiment 1 except that the temperature of the second sintering is 1450°C.

[0116] Example 6

[0117] This embodiment provides a method for preparing a MoTi alloy target, which is the same as that of Embodiment 1 except that the temperature of the second sintering is 1550°C.

[0118] Example 7

[0119] This embodiment provides a method for preparing a MoTi alloy target, which is the same as that of Embodiment 1 except that the temperature of the second sintering is 1600°C.

[0120] Example 8

[0121] This embodiment provides a method for preparing a MoTi alloy target, which is the same as that of Embodiment 1 except that the temperature of the second sintering is 1300°C.

[0122] Example 9

[0123] This embodiment provides a method for preparing a MoTi alloy target, which is the same as that of Embodiment 1 except that the temperature of the second sintering is 1700°C.

[0124] The second sintering temperature in this embodiment is too high, and a liquid phase appears during the second sintering process, resulting in agglomeration of Ti elements and uneven element distribution.

[0125] Example 10

[0126] This embodiment provides a method for preparing a MoTi alloy target, which is the same as that of Embodiment 1 except that the first sintering is not performed.

[0127] Embodiment 11

[0128] This embodiment provides a method for preparing a MoTi alloy target, which is the same as that of Embodiment 1 except that the Fisher particle size of the titanium powder is 30 μm.

[0129] Example 12

[0130] This embodiment provides a method for preparing a MoTi alloy target, which is the same as that of Embodiment 1 except that the Fisher particle size of the titanium powder is 40 μm.

[0131] Data Characterization

[0132] The density and oxygen content of the MoTi alloy target obtained in Examples 1-12 were measured. The density was measured according to the method of GB / T3850-2015; the oxygen content was measured using an oxygen, nitrogen and hydrogen analyzer; the results are shown in Table 1.

[0133] Table 1

[0134]

[0135]

[0136] In summary, the preparation method provided by the present invention does not require hot isostatic pressing, has high efficiency and low cost; moreover, the present invention mixes molybdenum powder and titanium powder to make the elements evenly distributed, and since the mixed powder has a small specific surface area and a large activation energy, it can also have a higher density at the same sintering temperature; in addition, the present invention combines cold isostatic pressing with vacuum sintering to increase the sintering temperature, thereby obtaining a MoTi alloy target with a density of more than 96.13% and an oxygen content of less than 1893ppm.

[0137] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific 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 in the protection scope of the present invention.

Claims

1. A method for preparing a MoTi alloy target, characterized in that: The preparation method comprises the following steps: Molybdenum powder and titanium powder are mixed to obtain mixed powder; the mixed powder is then cold isostatically pressed to obtain a molybdenum-titanium green body; and the molybdenum-titanium green body is vacuum sintered to obtain the MoTi alloy target.

2. The preparation method according to claim 1, characterized in that: The molybdenum powder has a Fisher particle size of 2-6 μm; Preferably, the purity of the molybdenum powder is 3N or above.

3. The preparation method according to claim 1 or 2, characterized in that: The titanium powder has a Fisher particle size of 33-36 μm; Preferably, the purity of the titanium powder is 3N or above.

4. The preparation method according to any one of claims 1 to 3, characterized in that The mixing method is ball milling; Preferably, the rotation speed of the ball mill is 350-450r / min; Preferably, the ball milling time is 8-16h; Preferably, the ball-to-material ratio of the ball mill is 1:(4-6).

5. The preparation method according to claim 4, characterized in that: The ball milling is carried out in a protective atmosphere; Preferably, the gas used for the protective atmosphere includes nitrogen and / or an inert gas.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The cold isostatic pressing pressure is 200-300 MPa; Preferably, the cold isostatic pressing time is 5-40 min.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The vacuum sintering includes a first sintering and a second sintering performed sequentially.

8. The preparation method according to claim 7, characterized in that: The first sintering temperature is 700-1000°C and the time is 1-3h; Preferably, the second sintering is performed at a temperature of 1400-1600° C. and for a time of 3-6 hours.

9. The preparation method according to claim 7 or 8, characterized in that: The vacuum degree of the vacuum sintering is less than or equal to 1×10 -2 Pa.

10. The preparation method according to claim 1, characterized in that: The preparation method comprises: (1) In a protective atmosphere, ball milling is performed to mix molybdenum powder having a Fischer-Tropsch particle size of 2-6 μm and titanium powder having a Fischer-Tropsch particle size of 33-36 μm to obtain a mixed powder; The purity of the molybdenum powder is 3N or more; The purity of the titanium powder is 3N or above; The ball milling speed is 350-450r / min, the time is 8-16h, and the ball-to-material ratio is 1:(4-6); (2) cold isostatically pressing the mixed powder under a pressure of 200-300 MPa for 5-40 min to obtain a molybdenum-titanium green body; (3) Vacuum degree is less than or equal to 1×10 -2 Pa, vacuum sintering the molybdenum-titanium green body to obtain the MoTi alloy target; The vacuum sintering includes a first sintering and a second sintering performed sequentially; The first sintering temperature is 700-1000°C and the time is 1-3h; The second sintering is carried out at a temperature of 1400-1600° C. and for a time of 3-6 hours.

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