A method for preparing molybdenum disilicide target

Abstract

The present invention relates to a method for preparing a molybdenum disilicide target material, the preparation method comprising the following steps: (1) mixing molybdenum powder and silicon powder, and then ball milling to obtain a mixed powder; (2) hot pressing and sintering the mixed powder obtained in step (1) at 1200-1400° C. to obtain a blank; (3) machining the blank obtained in step (2) to obtain a target material. The preparation method provided by the present invention can obtain a target material containing a single phase of MoSi2, and has high purity and density, uniform microstructure, and can meet the performance requirements of the high-end electronics industry for the target material.

Description

Technical Field

[0001] The invention relates to the field of target materials, and in particular to a method for preparing a molybdenum disilicide target material. Background Art

[0002] MoSi 2 In the crystal structure, the bonding between Mo atoms is metallic bonding, and the bonding between Si atoms is covalent bonding. Therefore, MoSi2 contains both metallic bonding and covalent bonding, and has the dual properties of metal and ceramic. 2 、Ti 5 Si 3 , WSi 2 and TaSi 2 They are important candidate materials for large-scale integrated circuit gate and interconnect line films and are widely used in semiconductor chips, solar photovoltaics, flat panel displays, special coatings and other fields.

[0003] Currently, MoSi 2 Common preparation methods for ceramics include in-situ synthesis, self-propagating synthesis, mechanical alloying, pressureless sintering, reaction sintering or hot pressing sintering. Among them, the density obtained by pressureless sintering can only reach 90% of the theoretical density, and the density of the material cannot be further improved; the reaction sintering method is difficult to control the reaction rate due to the chemical reaction between the metal powders, and the product is greatly affected by the chemical composition, reaction atmosphere and thermal boundary conditions. Due to the expansion and the presence of oxide film on the particle surface, reaction sintering cannot guarantee a high level of density; the hot pressing sintering method can significantly improve the densification process and obtain MoSi with higher density. 2 ceramics, but MoSi prepared by hot pressing sintering 2 Ceramics often have uneven microstructure and phase composition, and the loss of silicon due to volatilization and oxidation of raw materials during sintering produces Mo. 5 Si 3 Equal issues.

[0004] For example, CN101445244A discloses a method for producing high-performance molybdenum disilicide rods, which comprises mixing molybdenum disilicide, additives, and water to form a mixture, kneading the mixture into a dough, and then pressing the dough into a green block, drying it; heating the green block to 1700-1800°C for high-temperature sintering, and then forming a cooked block; and extruding the cooked block at 1000-1500°C into a rod. 5 Si 3 phase, which leads to MoSi 2 The purity of the sputtered film is reduced, affecting the quality of the sputtered film.

[0005] Therefore, it is of great significance to provide a method for preparing a molybdenum disilicide target material with improved density and purity and uniform organizational structure. Summary of the invention

[0006] In view of the above problems, the purpose of the present invention is to provide a method for preparing a molybdenum disilicide target. Compared with the prior art, the preparation method provided by the present invention can prepare a target with high density and purity and contains only MoSi 2 Single-phase molybdenum disilicide target material can meet the performance requirements of the high-end electronics industry for target materials.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for preparing a molybdenum disilicide target, the preparation method comprising the following steps:

[0009] (1) mixing molybdenum powder and silicon powder, and then ball milling to obtain a mixed powder;

[0010] (2) hot pressing and sintering the mixed powder obtained in step (1) at 1200-1400° C. to obtain a blank;

[0011] (3) Machining the blank obtained in step (2) to obtain a target material.

[0012] The preparation method provided by the present invention controls the uniformity of the mixed powder during the ball milling process, and on the other hand, controls the temperature of the hot pressing sintering within a specific range to avoid excessive liquid phase during the sintering process, thereby avoiding the loss of silicon due to volatilization and oxidation during the sintering process and thus causing Mo 5 Si 3 The problem of phase formation can be solved, so that a high density and purity can be prepared, and only MoSi 2 Single-phase molybdenum disilicide target material can meet the performance requirements of the high-end electronics industry for target materials.

[0013] Preferably, the average particle size of the molybdenum powder in step (1) is 5-8 μm, for example, it can be 5 μm, 5.2 μm, 5.4 μm, 5.6 μm, 5.8 μm, 6 μm, 6.2 μm, 6.4 μm, 6.6 μm, 6.8 μm, 7 μm, 7.2 μm, 7.4 μm, 7.6 μm, 7.8 μm or 8 μm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0014] Preferably, the purity of the molybdenum powder is ≥99.95%, for example, it can be 99.95%, 99.96%, 99.97%, 99.98% or 99.99%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] Preferably, the average particle size of the silicon powder in step (1) is 3-5 μm, for example, 3 μm, 3.2 μm, 3.4 μm, 3.6 μm, 3.8 μm, 4 μm, 4.2 μm, 4.4 μm, 4.6 μm, 4.8 μm or 5 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] In the present invention, by controlling the particle sizes of molybdenum powder and silicon powder within a specific range, the uniformity of mixing can be further improved, and problems such as component segregation can be avoided.

[0017] Preferably, the purity of the silicon powder is ≥99.999%, for example, it may be 99.9991%, 99.9992%, 99.9993%, 99.9994% or 99.9995%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] Preferably, the atomic ratio of molybdenum to silicon in the mixed powder of step (1) is 1:(2.05-2.1), for example, it can be 1:2.05, 1:2.06, 1:2.07, 1:2.08, 1:2.09 or 1:2.1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] In the present invention, by controlling the atomic ratio of molybdenum to silicon in the mixed powder within a specific range, the loss of silicon due to volatilization, oxidation, etc. during hot pressing and sintering, which in turn causes the loss of Mo, can be solved. 5 Si 3 The problem of phase generation further promotes the 2 Phase generation.

[0020] Preferably, the grinding balls used in the ball milling in step (1) include zirconium oxide balls.

[0021] Preferably, the mass ratio of the zirconia balls to the mixed powder is 1:(1.8-2.2), for example, it can be 1:1.8, 1:1.9, 1:2, 1:2.1 or 1:2.2, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, the grinding balls include any one of zirconia balls with a diameter of 5 mm, zirconia balls with a diameter of 10 mm, or zirconia balls with a diameter of 15 mm, or a combination of at least two of them.

[0023] Preferably, the mass ratio of the zirconia balls with a diameter of 5 mm, the zirconia balls with a diameter of 10 mm and the zirconia balls with a diameter of 15 mm is 1:(8-12):(8-12), for example, it can be 1:8:8, 1:8:9, 1:8:10, 1:8:11, 1:8:12, 1:9:8, 1:10:8, 1:11:8 or 1:12:8, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] In the present invention, it is preferred to control the mass ratio of zirconia balls to the mixed powder within a specific range, and it is preferred to use zirconia balls with a diameter of 5 mm, zirconia balls with a diameter of 10 mm, and zirconia balls with a diameter of 15 mm and control their mass ratio, which can further promote the mixing of molybdenum powder and silicon powder, improve uniformity, and be more conducive to the formation of MoSi 2 Single phase.

[0025] Preferably, the rotation speed of the ball mill in step (1) is 10-15 r / min, for example, it can be 10 r / min, 11 r / min, 12 r / min, 13 r / min, 14 r / min or 15 r / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] Preferably, the ball milling time is 22-26 hours, for example, 22 hours, 23 hours, 24 hours, 25 hours or 26 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0027] In the present invention, it is preferred to control the speed and time of ball milling to promote the uniformity of the mixed powder, thereby facilitating the formation of MoSi 2 Single phase.

[0028] Preferably, the ball milling in step (1) is carried out under a protective atmosphere.

[0029] Preferably, the protective atmosphere comprises nitrogen and / or an inert gas.

[0030] Preferably, the hot pressing sintering process in step (2) includes heating and heat preservation in sequence.

[0031] Preferably, the heating rate is 5-10°C / min, for example, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min or 10°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the terminal temperature of the heating is 1200-1400°C, for example, it can be 1200°C, 1220°C, 1250°C, 1280°C, 1300°C, 1320°C, 1350°C, 1380°C or 1400°C, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 1250-1350°C.

[0033] Preferably, the temperature is kept at the endpoint temperature.

[0034] Preferably, the insulation time is 2-3h, for example, 2h, 2.2h, 2.4h, 2.6h, 2.8h or 3h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the heat preservation is performed while the pressure is maintained.

[0036] Preferably, the holding pressure is 30-40 MPa, for example, 30 MPa, 32 MPa, 34 MPa, 36 MPa, 38 MPa or 40 MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0037] In the present invention, by controlling the temperature, pressure and time of the insulation within a specific range, the compactness of the target material can be further improved, and MoSi 2 Single phase.

[0038] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0039] (1) mixing molybdenum powder with an average particle size of 3-5 μm and a purity of ≥99.95% and silicon powder with an average particle size of 3-5 μm and a purity of ≥99.999%, and then ball milling them for 22-26 hours using a zirconium oxide ball at a rotation speed of 10-15 r / min and a protective atmosphere of nitrogen to obtain a mixed powder;

[0040] The atomic ratio of molybdenum to silicon in the mixed powder is 1:(2.05-2.1), and the mass ratio of the zirconium oxide ball to the mixed powder is 1:(1.8-2.2);

[0041] (2) heating the mixed powder obtained in step (1) to an end temperature of 1200-1400° C. at a heating rate of 5-10° C. / min, and then maintaining the temperature at 1200-1400° C. and a pressure of 30-40 MPa for 2-3 hours to obtain a blank;

[0042] (3) Machining the blank obtained in step (2) to obtain a target material.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The preparation method provided by the present invention can obtain MoSi 2 The single-phase target material has a density of more than 96% and a uniform microstructure, which can meet the performance requirements of the high-end electronics industry for target materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is the XRD diagram of the target material obtained in Example 3 of the present invention.

[0046] Figure 2 This is a SEM image of the target material obtained in Example 4 of the present invention. DETAILED DESCRIPTION

[0047] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0048] Example 1

[0049] This embodiment provides a method for preparing a molybdenum disilicide target, and the preparation method comprises the following steps:

[0050] (1) Molybdenum powder with an average particle size of 4 μm and a purity of 99.95% and silicon powder with an average particle size of 4 μm and a purity of 99.999% are mixed, and then ball milled for 24 hours using a zirconium oxide ball at a rotation speed of 12 r / min and a protective atmosphere of nitrogen to obtain a mixed powder;

[0051] The atomic ratio of molybdenum to silicon in the mixed powder is 1:2.06, and the mass ratio of the zirconia balls to the mixed powder is 1:2.0; the grinding balls include zirconia balls with a diameter of 5 mm, zirconia balls with a diameter of 10 mm, and zirconia balls with a diameter of 15 mm, and the mass ratio is 1:10:10;

[0052] (2) heating the mixed powder obtained in step (1) to an end point temperature of 1300° C. at a heating rate of 7° C. / min, and then maintaining the temperature at 1300° C. and a pressure of 35 MPa for 2.5 h to obtain a blank;

[0053] (3) Machining the blank obtained in step (2) to obtain a target material.

[0054] Example 2

[0055] This embodiment provides a method for preparing a molybdenum disilicide target, and the preparation method comprises the following steps:

[0056] (1) Molybdenum powder with an average particle size of 3 μm and a purity of 99.96% and silicon powder with an average particle size of 3 μm and a purity of 99.9991% are mixed, and then ball milled for 26 hours using a zirconium oxide ball at a rotation speed of 10 r / min and a protective atmosphere of nitrogen to obtain a mixed powder;

[0057] The atomic ratio of molybdenum to silicon in the mixed powder is 1:2.05, and the mass ratio of the zirconia balls to the mixed powder is 1:1.8; the grinding balls include zirconia balls with a diameter of 5 mm, zirconia balls with a diameter of 10 mm, and zirconia balls with a diameter of 15 mm, and the mass ratio is 1:8:8;

[0058] (2) heating the mixed powder obtained in step (1) to an end point temperature of 1250° C. at a heating rate of 5° C. / min, and then maintaining the temperature at 1250° C. and a pressure of 40 MPa for 2 h to obtain a blank;

[0059] (3) Machining the blank obtained in step (2) to obtain a target material.

[0060] Example 3

[0061] This embodiment provides a method for preparing a molybdenum disilicide target, and the preparation method comprises the following steps:

[0062] (1) Molybdenum powder with an average particle size of 5 μm and a purity of 99.97% and silicon powder with an average particle size of 5 μm and a purity of 99.9992% are mixed, and then ball milled for 22 hours using a zirconium oxide ball at a rotation speed of 15 r / min and a protective atmosphere of nitrogen to obtain a mixed powder;

[0063] The atomic ratio of molybdenum to silicon in the mixed powder is 1:2.1, and the mass ratio of the zirconia balls to the mixed powder is 1:2.2; the grinding balls include zirconia balls with a diameter of 5 mm, zirconia balls with a diameter of 10 mm, and zirconia balls with a diameter of 15 mm, and the mass ratio is 1:12:12;

[0064] (2) heating the mixed powder obtained in step (1) to an end temperature of 1350° C. at a heating rate of 10° C. / min, and then maintaining the temperature at 1350° C. and a pressure of 40 MPa for 3 h to obtain a blank;

[0065] (3) Machining the blank obtained in step (2) to obtain a target material.

[0066] Example 4

[0067] This embodiment provides a method for preparing a molybdenum disilicide target. The difference between the preparation method and embodiment 1 is that the atomic ratio of molybdenum to silicon in the mixed powder is 1:2.

[0068] Example 5

[0069] This embodiment provides a method for preparing a molybdenum disilicide target. The difference between the preparation method and embodiment 1 is that the atomic ratio of molybdenum to silicon in the mixed powder is 1:2.3.

[0070] The density of the target materials obtained in Examples 1-5 was tested by the Archimedes drainage method. The results are shown in Table 1.

[0071] The compositions of the targets obtained in Examples 1-5 were tested by XRD. The results are shown in Table 1. Taking Example 3 as an example, the results are shown in Table 1. Figure 1 As shown, from Figure 1 It can be seen that the target material obtained in this embodiment is MoSiO 2 Pure phase.

[0072] Taking Example 4 as an example, the obtained target material was subjected to SEM and EDS detection, and the obtained SEM image is as follows: Figure 2 As shown, from Figure 2 It can be seen that the target contains Mo 5 Si 3 Phase and MoSi 2 Phase, respectively, for Mo 5 Si 3 Phase and MoSi 2 The phase was analyzed by EDS and Mo 5 Si 3 The content of Mo in the alloy is 85.39%, and the content of Si is 14.61%. 2 The Mo content is 63.53%, and the Si content is 36.47%.

[0073] Table 1

[0074] Density / % XRD detection of crystal phase composition Example 1 96 <![CDATA[MoSi 2 Single phase]]> Example 2 97.5 <![CDATA[MoSi 2 Single phase]]> Example 3 99 <![CDATA[MoSi 2 Single phase]]> Example 4 93 <![CDATA[MoSi 2 Harmony Mo 5 S 3 [phase]]> Example 5 97 <![CDATA[MoSi 2 Phase and Si phase]]>

[0075] From the data in Table 1, we can see the following points:

[0076] (1) The preparation method provided by the present invention can obtain MoSi 2 The single-phase target material has a density of more than 96% and a uniform microstructure, which can meet the performance requirements of the high-end electronics industry for target materials.

[0077] (2) Comprehensively comparing the data of Example 1 and Examples 4-5, it can be seen that the difference between Example 4-5 and Example 1 is that the atomic ratio of molybdenum to silicon is not within the preferred range of the present invention. Example 1 can obtain a MoSi 2 Single-phase target, while Mo 5 Si 3phase or Si phase, resulting in a decrease in the purity of the target material. It can be seen that the present invention preferably controls the atomic ratio of molybdenum and silicon within a specific range, which can further improve the purity of the target material and obtain a MoSi 2 Single-phase target.

[0078] In summary, the preparation method provided by the present invention can obtain MoSi 2 The single-phase target material has high purity and density, and a uniform microstructure, which can meet the performance requirements of the high-end electronics industry for target materials.

[0079] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a molybdenum disilicide target, characterized in that: The preparation method comprises the following steps: (1) mixing molybdenum powder and silicon powder, and then ball milling to obtain a mixed powder; The atomic ratio of molybdenum to silicon in the mixed powder is 1:(2.05-2.1); (2) hot pressing and sintering the mixed powder obtained in step (1) at 1200-1400° C. to obtain a blank; The hot pressing sintering process includes heating and heat preservation in sequence; The heating rate is 5-10°C / min, and the end temperature is 1200-1400°C; the end temperature is kept warm for 2-3h; The heat preservation is also performed while maintaining pressure, and the pressure of the pressure maintenance is 30-40MPa; (3) machining the blank obtained in step (2) to obtain a target material; The preparation method obtains a target material containing a MoSi2 single phase, and the target material has high purity and density and a uniform microstructure.

2. The preparation method according to claim 1, characterized in that: The average particle size of the molybdenum powder in step (1) is 5-8 μm.

3. The preparation method according to claim 1, characterized in that: The purity of the molybdenum powder in step (1) is ≥99.95%.

4. The preparation method according to claim 1, characterized in that: The average particle size of the silicon powder in step (1) is 3-5 μm.

5. The preparation method according to claim 1, characterized in that: The purity of the silicon powder in step (1) is ≥99.999%.

6. The preparation method according to claim 1, characterized in that: The grinding balls used in the ball milling in step (1) include zirconium oxide balls.

7. The preparation method according to claim 6, characterized in that: The mass ratio of the zirconia balls to the mixed powder is 1:(1.8-2.2).

8. The preparation method according to claim 6, characterized in that: The grinding balls include any one of zirconia balls with a diameter of 5 mm, zirconia balls with a diameter of 10 mm, or zirconia balls with a diameter of 15 mm, or a combination of at least two of them.

9. The preparation method according to claim 8, characterized in that: The mass ratio of the zirconia balls with a diameter of 5 mm, the zirconia balls with a diameter of 10 mm, and the zirconia balls with a diameter of 15 mm is 1:(8-12):(8-12).

10. The preparation method according to claim 1, characterized in that: The rotation speed of the ball mill in step (1) is 10-15 r / min.

11. The preparation method according to claim 1, characterized in that: The ball milling time in step (1) is 22-26 hours.

12. The preparation method according to claim 1, characterized in that: The ball milling in step (1) is carried out under a protective atmosphere.

13. The preparation method according to claim 12, characterized in that: The protective atmosphere includes nitrogen and / or an inert gas.

14. The preparation method according to claim 1, characterized in that: The terminal temperature of the heating is 1250-1350°C.

15. The preparation method according to claim 1, characterized in that: The preparation method comprises the following steps: (1) mixing molybdenum powder with an average particle size of 3-5 μm and a purity of ≥99.95% and silicon powder with an average particle size of 3-5 μm and a purity of ≥99.999%, and then ball milling them for 22-26 hours using a zirconium oxide ball at a rotation speed of 10-15 r / min and a protective atmosphere of nitrogen to obtain a mixed powder; The atomic ratio of molybdenum to silicon in the mixed powder is 1:(2.05-2.1), and the mass ratio of the zirconium oxide ball to the mixed powder is 1:(1.8-2.2); (2) heating the mixed powder obtained in step (1) to an end temperature of 1200-1400° C. at a heating rate of 5-10° C. / min, and then maintaining the temperature at 1200-1400° C. and a pressure of 30-40 MPa for 2-3 hours to obtain a blank; (3) Machining the blank obtained in step (2) to obtain a target material.

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