High-purity high-uniformity low-oxygen molybdenum-silicon alloy target material and preparation method thereof

Abstract

The application belongs to the technical field of magnetron sputtering target material manufacturing, and discloses a high-purity high-uniformity low-oxygen molybdenum-silicon alloy target material and a preparation method thereof. The molybdenum-silicon alloy target material uses a molybdenum block and a silicon block as raw materials, first obtains a high-purity segregation-free low-oxygen Mo3Si alloy ingot through smelting, and then, after pickling, uses a crucible-free atomization powdering method to screen and prepare high-purity low-oxygen spherical Mo3Si alloy powder. Finally, the Mo powder is mixed and vacuum hot-pressed sintered to obtain a high-purity molybdenum-silicon alloy target material with a Si content of ≤25wt%, a size of ≥300mm, a purity of ≥4N, a density of ≥99.5%, an average grain size of ≤20μm, a Si content composition fluctuation of the whole target surface of ≤±0.5wt%, and an oxygen content of ≤100ppm.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of magnetron sputtering target material manufacturing, and particularly relates to a high-purity high-uniformity low-oxygen molybdenum-silicon alloy target material and a preparation method thereof. BACKGROUND

[0002] Molybdenum-silicon alloy target material has a high melting point and excellent oxidation resistance and is widely used in the preparation of a photomask layer of a semiconductor mask. High-purity molybdenum-silicon alloy target is a key material for a semiconductor mask, and with the continuous development of the technology node of integrated circuits, the wavelength of the exposure light source of the semiconductor mask is continuously reduced. Therefore, the preparation of high-purity molybdenum-silicon alloy target material with high density, high composition uniformity, high purity and low oxygen plays a key role in the film plating process of the semiconductor mask.

[0003] Molybdenum-silicon alloy target material is mainly sintered by powder metallurgy process, and the process includes: (1) hot pressing (HP) of mixed molybdenum powder and silicon powder, which can be referred to in patent CN104513953B; (2) cold pressing and then hot pressing of mixed molybdenum powder and silicon powder, which can be referred to in patent CN105483624B; (3) cold pressing and then hot isostatic pressing (HIP) of mixed molybdenum powder and silicon powder, which can be referred to in patent CN105642899B; and (4) hot pressing (HP) of mixed molybdenum disilicide powder and silicon powder after ball milling, which can be referred to in patent CN117024124A.

[0004] The above processes are all using elemental molybdenum powder and elemental silicon powder or molybdenum disilicide powder and elemental silicon powder as raw materials, mixing the powders by ball milling, and then forming, which has the following disadvantages: (1) the morphology of conventional elemental molybdenum powder, elemental silicon powder and molybdenum disilicide powder is irregular polygon, which is difficult to change after ball milling, and the flowability of the polygonal powder is poor in the later pressing and sintering process, so it is difficult to obtain a high-density defect-free molybdenum-silicon alloy target; (2) the purity of conventional elemental molybdenum powder, elemental silicon powder and molybdenum disilicide powder is poor (the purity is usually 3N5), and the oxygen content is high (usually 500-1000ppm), which is easy to introduce impurities after ball milling, and it is difficult to prepare a high-purity low-oxygen molybdenum-silicon alloy target; (3) the MoSi alloy target with Si content ≤25wt% is composed of elemental Mo phase and Mo3Si alloy phase, if the elemental molybdenum powder and elemental silicon powder are ball-mixed, a molybdenum-silicon alloy phase needs to be generated in the later pressing and sintering process, which is an exothermic reaction, resulting in uneven heat in the sintering process, and the target is easy to crack when preparing a large-size target (size greater than 200mm); (4) if the MoSi2 and elemental Si ball-mixed process is used to prepare the MoSi alloy target, it can only prepare a MoSi alloy target with Si content of 36.9wt% or more, and cannot prepare a MoSi alloy target with Si content of less than 25wt%; (5) the density of elemental molybdenum and elemental silicon is quite different, and it is difficult to achieve uniform distribution of molybdenum and silicon powders after ball-milling of elemental molybdenum and elemental silicon powders, so the composition uniformity of the large-size molybdenum-silicon alloy target prepared is poor.

[0005] Therefore, it is urgent to provide a molybdenum-silicon alloy target with high purity, high oxygen content, Si content less than or equal to 25wt%, good density and uniformity, and a preparation method suitable for large-size target. SUMMARY

[0006] In view of the problems in the prior art, the application discloses a preparation method of a high-purity high-uniformity low-oxygen molybdenum-silicon alloy target.

[0007] To solve the above problems, the patent provides a preparation method of high-purity high-uniformity low-oxygen molybdenum-silicon alloy target material: (1) The present application belongs to the technical field of magnetron sputtering target material manufacturing, and discloses a preparation method of high-purity high-uniformity low-oxygen molybdenum-silicon alloy target material. The molybdenum-silicon alloy target material uses a molybdenum block with a purity greater than 3N5 and a silicon block with a purity greater than 6N as raw materials, first obtains a high-purity non-segregation low-oxygen Mo3Si alloy ingot through melting, obtains Mo3Si alloy rods after pickling, and then uses the non-crucible atomization powder preparation method to prepare high-purity low-oxygen spherical Mo3Si alloy powder through screening. Finally, the Mo powder is mixed and vacuum hot-pressed sintered to obtain a high-purity molybdenum-silicon alloy target material with a Si content of ≤25wt%, a size of ≥300mm, a purity of ≥4N, a density of ≥99.5%, an average grain size of ≤20μm, a whole target surface Si content composition fluctuation of ≤±0.5wt%, and an oxygen content of ≤100ppm. Compared with the existing process scheme, the present application has the following advantages: (1) The process of sintering the spherical Mo3Si powder mixed with spherical Mo powder improves the shortcomings of the existing process technology, such as poor flowability of the polygonal powder. The spherical powder can supplement defects in the subsequent forming process, avoid the generation of defects, and prepare molybdenum-silicon alloy target material with high density and few defects; (2) The present application uses high-purity molybdenum blocks and silicon blocks as raw materials, and prepares alloy ingots through melting, which avoids the introduction of impurities in the ball milling and mixing process, and removes part of the impurities in the melting process, thereby achieving the effect of purification and high purity; (3) The present application directly prepares Mo3Si powder, which can avoid the exothermic reaction of Mo3Si generated by the reaction of elemental Mo and elemental Si in the later pressing and sintering process, and can prepare large-size molybdenum-silicon alloy target material with a diameter of ≥300mm; (4) The present application directly synthesizes Mo3Si alloy powder, and the density of Mo3Si is close to that of elemental Mo. Mixing Mo3Si with Si can further improve the composition uniformity of the target material, and the whole target surface Si content composition fluctuation is ≤±0.5wt%.

[0008] The present application adopts the following technical solutions:

[0009] A preparation method of high-purity high-uniformity low-oxygen molybdenum-silicon alloy target material, the steps of which are as follows:

[0010] (1) Preparation of raw materials: according to the atomic ratio of high-purity molybdenum Mo and high-purity silicon Si Mo:Si=3:1;

[0011] Among them, the purity of high-purity Mo is >3N5, and the oxygen content is <100ppm;

[0012] The purity of high-purity Si is >6N, and the oxygen content is <50ppm;

[0013] (2) After the high-purity Mo and high-purity Si are melted, Mo3Si alloy ingots are obtained by pouring;

[0014] (3) pickling the Mo3Si alloy ingot to remove the oxide skin on the surface of the ingot, to obtain a Mo3Si alloy powder rod;

[0015] (4) powdering the Mo3Si alloy powder rod in a crucible-free powdering furnace, to obtain a Mo3Si alloy powder;

[0016] (5) mixing the Mo3Si alloy powder and Mo powder in a powder mixing tank, to obtain a MoSi alloy powder;

[0017] (6) vacuum hot-pressing sintering the MoSi alloy powder to obtain a molybdenum-silicon alloy target.

[0018] In some preferred embodiments, in the step (4), the particle size of the Mo3Si alloy powder is ≤2 μm; preferably, 0.5-1.5 μm; preferably, the Mo3Si alloy powder is obtained by screening, to obtain a spherical Mo3Si alloy powder with a particle size of 0.5-1.5 μm.

[0019] In some preferred embodiments, in the step (4), the Mo3Si alloy powder has a spherical morphology;

[0020] In some preferred embodiments, in the step (4), the purity of the Mo3Si alloy powder is ≥4N5, and the oxygen content is ≤100 ppm.

[0021] In some preferred embodiments, in the step (4), the powdering gas pressure is 2-3 MPa; if the powdering gas pressure is less than 2 MPa, hollow spherical powder and irregularly shaped powder are easily formed; if the powdering gas pressure is greater than 3 MPa, satellite spherical powder is formed;

[0022] In some preferred embodiments, in the step (2), the temperature of the melting is 2400-2500℃; if the temperature of the melting is less than 2400℃, the MoSi alloy cannot be melted; if the temperature of the melting is greater than 2500℃, the Si component is easily volatilized;

[0023] In some preferred embodiments, in the step (2), the purity of the Mo3Si alloy ingot is ≥5N, the oxygen content is ≤80 ppm, and the Si component fluctuation is ≤±1 at.%;

[0024] In some preferred embodiments, in the step (2), the number of times of the melting is 2-5 times; if the number of times of the melting is too small, the composition of the MoSi alloy ingot is not uniform, and a powder and a target with uniform composition cannot be obtained; if the number of times of the melting is too large, the composition uniformity of the ingot cannot be further improved, the steps are tedious, and energy is wasted;

[0025] In some preferred embodiments, in step (2), an inert gas is used as a protective gas during the smelting process; preferably Ar gas.

[0026] In some preferred embodiments, in step (5), the purity of the Mo powder is > 4N; the morphology of the Mo powder is spherical.

[0027] In some preferred embodiments, the purity of the Mo-Si alloy target material is ≥ 4N, the Si content is ≤ 25wt%, the oxygen content is ≤ 100ppm, and the balance is Mo.

[0028] In some preferred embodiments, the size of the Mo-Si alloy target material is ≥ 300mm.

[0029] In some preferred embodiments, the density of the Mo-Si alloy target material is ≥ 99.5%, and the average grain size is ≤ 20μm.

[0030] In some preferred embodiments, the Si content component fluctuation of the entire target surface of the Mo-Si alloy target material is ≤ ± 0.5wt%.

[0031] In some preferred embodiments, the conditions of the vacuum hot pressing sintering are optionally: temperature is 1000-1400℃, pressure is 10-30MPa, and time is 1-6h.

[0032] In some preferred embodiments, the process of the vacuum hot pressing sintering is carried out in a vacuum hot pressing furnace.

[0033] In addition, the application also provides a high-purity high-uniformity low-oxygen Mo-Si alloy target material prepared by the preparation method.

[0034] The beneficial effects of the application are:

[0035] (1) High purity: The technical solution adopts elemental Mo blocks and elemental Si blocks as raw materials, prepares alloy ingots by smelting, and then grinds the alloy ingots into powder, which avoids the introduction of impurities in the ball milling and mixing process, and removes part of the impurities during the smelting process, thereby achieving the effect of purification, and the purity is ≥ 4N.

[0036] (2) Low oxygen content: The application adopts elemental Mo blocks and elemental Si blocks as raw materials, prepares alloy ingots by smelting, and then grinds the alloy ingots into powder, which is carried out in a vacuum or under Ar gas protection throughout the process, thereby avoiding a large increase in oxygen content, and the oxygen content of the prepared Mo-Si alloy target material is ≤ 100ppm.

[0037] (3) High density and few target material defects: The powder prepared by the application is spherical, and compared with conventional polygonal flaky elemental Mo powder and elemental Si powder, it has good fluidity, can supplement defects in time during the subsequent forming process, and avoid the generation of defects, so that the prepared Mo-Si alloy target material has high density and few target material defects.

[0038] (4) Can prepare large size uncracked target: MoSi alloy target with Si content ≤25wt% is composed of elemental Mo phase and Mo3Si alloy phase, if using elemental molybdenum powder and elemental silicon powder ball milling process, the reaction of generating molybdenum silicon alloy phase is needed in the later pressing sintering process, this reaction is exothermic reaction, leading to uneven heat in the sintering process, easy to crack when preparing large size target. The technical solution directly prepares Mo3Si powder, which can avoid the exothermic reaction of generating Mo3Si from elemental Mo and elemental Si in the later pressing sintering process, the heat of the target is uniform, and large size molybdenum silicon alloy target with a diameter ≥300mm can be prepared.

[0039] (5) Good component uniformity: the density of elemental molybdenum and elemental silicon is quite different, after ball milling of elemental molybdenum powder and elemental silicon powder, it is difficult to achieve uniform distribution of molybdenum powder and silicon powder, and the component uniformity of the prepared large size molybdenum silicon alloy target is poor. The technical solution directly synthesizes Mo3Si alloy powder, the density of Mo3Si is close to that of elemental Mo, and the component uniformity of the target can be further improved by mixing Mo3Si and Si, and the Si content component fluctuation of the whole target surface is ≤±0.5wt%. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The patent application relates to a molybdenum silicon alloy target preparation method flow chart. DETAILED DESCRIPTION

[0041] The application mechanism of the application is as follows: taking molybdenum blocks with a purity greater than 3N5 and silicon blocks with a purity greater than 6N as raw materials, high-purity and low-oxygen Mo3Si alloy ingots are obtained through repeated smelting, high-purity and low-oxygen spherical Mo3Si alloy powder is prepared by using the Mo3Si alloy ingots for crucible-free atomization, the alloy powder is mixed with elemental spherical Mo powder with a purity greater than 4N, and then filled into a mold for vacuum hot pressing sintering, and finally, a large-size molybdenum silicon alloy target with high purity, low oxygen content and good component uniformity is obtained. The application mechanism avoids the impurity introduction process such as crushing and ball milling in the conventional powder preparation process, and the prepared target has high purity, low oxygen content, high sphericity of the alloy powder, good flowability, high density and few defects, the component uniformity of the alloy powder is better than that of the conventional elemental powder, the prepared target has high component uniformity, and the cracking caused by exothermic reaction of the elemental powder in the later sintering process is avoided, so that a large-size molybdenum silicon alloy target can be prepared.

[0042] In order to better explain the application and facilitate understanding, the application is described in detail below through specific implementation cases and comparison cases. The application is further described below through the drawings and specific implementation modes, but this does not mean that the protection scope of the application is limited.

[0043] A preparation method of high-purity high-uniformity low-oxygen molybdenum-silicon alloy target material, as shown in Figure 1 The steps are as follows:

[0044] (1) Preparation of raw materials: high-purity molybdenum Mo and high-purity silicon are prepared according to the atomic ratio Mo: Si = 3: 1;

[0045] Among them, the purity of high-purity Mo is > 3N5, and the oxygen content is < 100ppm;

[0046] The purity of high-purity Si is > 6N, and the oxygen content is < 50ppm;

[0047] (2) The high-purity Mo and high-purity Si prepared in step (1) are melted multiple times, and Mo3Si alloy ingots are obtained by pouring;

[0048] The melting temperature is 2400-2500℃, if the powdering gas pressure is less than 2MPa, hollow spherical powder and irregular shaped powder are easily formed; if the powdering gas pressure is greater than 3MPa, satellite ball powder is formed;

[0049] The melting times are 2-5 times, if the melting times are too few, the composition of MoSi alloy ingots is not uniform, and uniform composition powder and target material cannot be obtained; if the melting times are too many, the composition uniformity of the ingots will not be improved, the steps are complicated, and energy is wasted;

[0050] In order to prevent Si volatilization, inert gas is used as protective gas during melting; preferably Ar gas;

[0051] The purity of the Mo3Si alloy ingot is ≥5N, the oxygen content is ≤80ppm, and the Si composition fluctuation is ≤±1at.%;

[0052] (3) The Mo3Si alloy ingot obtained in step (2) is pickled to remove the surface oxide scale, and a high-purity Mo3Si alloy powder rod is obtained;

[0053] (4) In order to prevent the high-purity Mo3Si alloy from reacting with the powdering crucible during powdering and introducing impurities, the Mo3Si alloy powder rod obtained in step (3) is powdering in a crucible-free powdering furnace, and the powdering gas pressure is 2-3MPa, and finally Mo3Si alloy powder is obtained; the purity of the Mo3Si alloy powder is ≥4N5, the oxygen content is ≤100ppm, and the particle size is ≤2μm; the morphology of the Mo3Si alloy powder is spherical. If the powdering gas pressure is less than 2MPa, hollow spherical powder and irregular shaped powder are easily formed; if the powdering gas pressure is greater than 3MPa, satellite ball powder is formed.

[0054] Preferably, the Mo3Si alloy powder is sieved to obtain spherical Mo3Si alloy powder with a particle size of 0.5-1.5μm.

[0055] (5) The Mo3Si alloy powder obtained in step (4) is mixed with elemental spherical Mo powder with purity > 4N in a powder mixing tank to obtain MoSi alloy powder.

[0056] (6) The MoSi alloy powder obtained in step (5) is vacuum hot-pressed and sintered to obtain a molybdenum-silicon alloy target material; the Si content of the molybdenum-silicon alloy target material is ≤ 25wt%, the size is ≥ 300mm, the purity is ≥ 4N, the density is ≥ 99.5%, the average grain size is ≤ 20μm, the Si content composition fluctuation of the overall target surface is ≤ ± 0.5wt%, and the oxygen content is ≤ 100ppm.

[0057] The temperature of the vacuum hot-pressing sintering is 1000-1400℃, the pressure is 10-30MPa, and the time is 1-6h.

[0058] The vacuum hot-pressing sintering process is carried out in a vacuum hot-pressing furnace.

[0059] Examples 1-8

[0060] 1. Weighing: Prepare high-purity molybdenum with purity > 3N5 and oxygen content < 100ppm, and high-purity Si with purity > 6N and oxygen content < 50ppm, and weigh the corresponding weights of high-purity molybdenum and high-purity silicon according to the atomic ratio Mo:Si = 3:1.

[0061] 2. Melting: Repeat melting multiple times, and introduce high-purity Ar gas during each melting to prevent Si volatilization. The melting temperature is 2400-2500℃, and then cast to form a Mo3Si alloy ingot with purity ≥ 5N, oxygen content ≤ 80ppm, and Si composition fluctuation ≤ ± 1at.%.

[0062] 3. Pickling: Pickle the obtained Mo3Si alloy ingot to remove the surface oxide scale, and obtain a high-purity Mo3Si alloy powder rod.

[0063] 4. Powdering: To prevent the high-purity Mo3Si alloy from reacting with the powdering crucible during powdering and introducing impurities, the obtained high-purity Mo3Si alloy powder rod is placed in a crucible-free powdering furnace for powdering, and the powdering gas pressure is 2-3MPa, to finally obtain spherical Mo3Si alloy powder with purity ≥ 4N5, oxygen content ≤ 100ppm, and particle size ≤ 2μm.

[0064] Screening: The obtained high-purity Mo3Si powder is screened to obtain spherical Mo3Si alloy powder with particle size of 0.5-1.5μm.

[0065] 5. Powder mixing: According to the composition requirement of MoSi alloy target material with Si content ≤ 25wt%, the obtained 0.5-1.5μm spherical Mo3Si alloy powder is mixed with elemental spherical Mo powder with purity > 4N after proportioning to obtain MoSi alloy powder.

[0066] 6. Hot-pressing sintering: the high-purity MoSi alloy powder obtained is loaded into a vacuum hot-pressing furnace for hot pressing, to obtain a high-purity molybdenum silicon alloy target material with a Si content of ≤25wt%, a size of ≥300mm, a purity of ≥4N, a density of ≥99.5%, an average grain size of ≤20μm, and a Si content composition fluctuation of ≤±0.5wt% on the whole target surface, and an oxygen content of ≤100ppm. The hot-pressing temperature is 1000-1400℃, the hot-pressing pressure is 10-30MPa, and the hot-pressing time is 1-6h.

[0067] Comparative Examples 1-4

[0068] 1. Weighing: the corresponding weight of elemental Mo powder (all purchased from Hunan Oute Rare Metal Co., Ltd.) and elemental Si powder (purchased from Zhejiang Kaihua Yuantong Silicon Industry Co., Ltd.) is weighed.

[0069] 2. Ball-milling mixing powder: Si balls are used as milling balls for mixing powder, and the mass percentage of mixed powder and silicon balls ranges from (4:1) to (1:1), and the mixing time is 24h.

[0070] 3. Vacuum hot-pressing sintering: the high-purity MoSi alloy powder obtained is loaded into a vacuum hot-pressing furnace for hot pressing, and the hot-pressing temperature is 1000-1400℃, the hot-pressing pressure is 10-30MPa, and the hot-pressing time is 1-6h.

[0071] Comparative Examples 5-8

[0072] 1. Weighing: the corresponding weight of commercially available elemental purity 5N polygonal Mo powder and purity 3N5 polygonal Mo3Si alloy powder (both purchased from Hunan Oute Rare Metal Co., Ltd.) is weighed, and the powder particle size is 0.5-1.5μm.

[0073] 2. Ball-milling mixing powder: Si balls are used as milling balls for mixing powder, and the mass percentage of mixed powder and silicon balls ranges from (4:1) to (1:1), and the mixing time is 24h.

[0074] 3. Vacuum hot-pressing sintering: the high-purity MoSi alloy powder obtained is loaded into a vacuum hot-pressing furnace for hot pressing, and the hot-pressing temperature is 1000-1400℃, the hot-pressing pressure is 10-30MPa, and the hot-pressing time is 1-6h.

[0075] Comparative Example 9

[0076] 1. Weighing: high-purity molybdenum with a purity of >3N5 and an oxygen content of <100ppm, and high-purity Si with a purity of >6N and an oxygen content of <50ppm are prepared, and the corresponding weight of high-purity molybdenum and high-purity silicon is weighed according to the atomic ratio Mo:Si=3:1.

[0077] 2. Melting: Melting 1 time, in order to prevent Si volatilization, high purity Ar gas is introduced during each melting. The melting temperature is 2400°C, and then the Mo3Si alloy ingot with purity of 5N, oxygen content of 86ppm and Si component fluctuation of ±2.5at.% is formed by pouring.

[0078] 3. Pickling: The Mo3Si alloy ingot obtained is pickled to remove the surface oxide scale of the ingot, and a high purity Mo3Si alloy powder rod is obtained.

[0079] 4. Powdering: In order to prevent the high purity Mo3Si alloy from reacting with the powdering crucible during powdering and introducing impurities, the high purity Mo3Si alloy powder rod obtained is loaded into a crucible-free powdering furnace for powdering, and the powdering gas pressure is 2MPa. Finally, spherical Mo3Si alloy powder with purity of 4N5, oxygen content of 110ppm and particle size of ≤2μm is obtained.

[0080] Screening: The high purity Mo3Si powder obtained is screened to obtain spherical Mo3Si alloy powder with particle size of 0.5-1.5μm.

[0081] 5. Powder mixing: According to the MoSi alloy target component requirement of Si content ≤25wt%, the 0.5-1.5μm spherical Mo3Si alloy powder obtained is mixed with elemental spherical Mo powder with purity >4N after proportioning, and MoSi alloy powder is obtained.

[0082] 6. Hot pressing sintering: The high purity MoSi alloy powder obtained is loaded into a vacuum hot pressing furnace for hot pressing, and finally high purity molybdenum silicon alloy target material with Si content ≤25wt%, size of 350mm, purity of 4N, density of 99.95%, average grain size of 5μm, overall target surface Si content component fluctuation of ±1.7wt% and oxygen content of 90ppm is obtained. The hot pressing temperature is 1000°C, the hot pressing pressure is 10MPa, and the hot pressing time is 1h.

[0083] Comparative Example 10

[0084] 1. Weighing: High purity molybdenum with purity >3N5 and oxygen content <100ppm and high purity Si with purity >6N and oxygen content <50ppm are prepared, and the corresponding weights of high purity molybdenum and high purity silicon are weighed according to the atomic ratio of Mo:Si=3:1.

[0085] 2. Melting: Melting 6 times, in order to prevent Si volatilization, high purity Ar gas is introduced during each melting. The melting temperature is 2400°C, and then the Mo3Si alloy ingot with purity of 5N5, oxygen content of 75ppm and Si component fluctuation of ±0.7at.% is formed by pouring.

[0086] 3. Pickling: The Mo3Si alloy ingot obtained is pickled to remove the surface oxide scale of the ingot, and a high purity Mo3Si alloy powder rod is obtained.

[0087] 4. Milling: In order to prevent the high-purity Mo3Si alloy from reacting with the milling crucible and introducing impurities during the milling process, the obtained high-purity Mo3Si alloy is loaded into a crucible-free milling furnace for milling, and the milling gas pressure is 2 MPa. Finally, spherical Mo3Si alloy powder with a purity of 4N6, an oxygen content of 87 ppm, and a particle size of ≤2 μm is obtained.

[0088] Screening: The obtained high-purity Mo3Si powder is screened to obtain spherical Mo3Si alloy powder with a particle size of 0.5-1.5 μm.

[0089] 5. Powder mixing: According to the composition requirements of the MoSi alloy target material with a Si content of ≤25 wt%, the obtained 0.5-1.5 μm spherical Mo3Si alloy powder is mixed with elemental spherical Mo powder with a purity of >4N after being proportioned, and MoSi alloy powder is obtained.

[0090] 6. Hot-pressing sintering: The obtained high-purity MoSi alloy powder is loaded into a vacuum hot-pressing furnace for hot-pressing, and finally a high-purity molybdenum-silicon alloy target material with a Si content of ≤25 wt%, a size of 350 mm, a purity of 4N2, a density of 99.96%, an average grain size of 6 μm, a whole target surface Si content composition fluctuation of ±0.4 wt%, and an oxygen content of 62 ppm is obtained. The hot-pressing temperature is 1000°C, the hot-pressing pressure is 10 MPa, and the hot-pressing time is 1 h.

[0091] Comparative Example 11

[0092] 1. Weighing: High-purity molybdenum with a purity of >3N5 and an oxygen content of <100 ppm and high-purity Si with a purity of >6N and an oxygen content of <50 ppm are prepared, and the corresponding weights of high-purity molybdenum and high-purity silicon are weighed according to the atomic ratio Mo:Si = 3:1.

[0093] 2. Melting: Melting is performed twice, and high-purity Ar gas is introduced during each melting to prevent Si volatilization. The melting temperature is 2300°C, and the ingot is not completely melted, so that a MoSi alloy ingot cannot be obtained.

[0094] Comparative Example 12

[0095] 1. Weighing: High-purity molybdenum with a purity of >3N5 and an oxygen content of <100 ppm and high-purity Si with a purity of >6N and an oxygen content of <50 ppm are prepared, and the corresponding weights of high-purity molybdenum and high-purity silicon are weighed according to the atomic ratio Mo:Si = 3:1.

[0096] 2. Melting: Melting is performed twice, and high-purity Ar gas is introduced during each melting to prevent Si volatilization. The melting temperature is 2600°C, and then a Mo3Si alloy ingot with a purity of 5N6, an oxygen content of 70 ppm, and a Si composition fluctuation of ±4 at.% is formed.

[0097] 3. Pickling: The obtained Mo3Si alloy ingot is pickled to remove the surface oxide scale of the ingot, and a high-purity Mo3Si alloy powder rod is obtained.

[0098] 4. Powdering: To prevent the high-purity Mo3Si alloy from reacting with the powdering crucible and introducing impurities during the powdering process, the obtained high-purity Mo3Si alloy powder rod is loaded into a crucible-free powdering furnace for powdering, and the powdering gas pressure is 2 MPa. Finally, spherical Mo3Si alloy powder with a purity of 4N7, an oxygen content of 80 ppm, and a particle size of ≤2 μm is obtained.

[0099] Screening: The obtained high-purity Mo3Si powder is screened to obtain spherical Mo3Si alloy powder with a particle size of 0.5-1.5 μm.

[0100] 5. Powder mixing: According to the composition requirements of the MoSi alloy target material with a Si content of ≤25 wt%, the obtained 0.5-1.5 μm spherical Mo3Si alloy powder is mixed with elemental spherical Mo powder with a purity of >4N after being proportioned, and MoSi alloy powder is obtained.

[0101] 6. Hot-pressing sintering: The obtained high-purity MoSi alloy powder is loaded into a vacuum hot-pressing furnace for hot-pressing, and finally a high-purity molybdenum-silicon alloy target material with a Si content of ≤25 wt%, a size of 350 mm, a purity of 4N3, a density of 99.95%, an average grain size of 5 μm, a whole target surface Si content composition fluctuation of ±3.5 wt%, and an oxygen content of 60 ppm is obtained. The hot-pressing temperature is 1000°C, the hot-pressing pressure is 10 MPa, and the hot-pressing time is 1 h.

[0102] Comparative Example 13

[0103] 1. Weighing: High-purity molybdenum with a purity of >3N5 and an oxygen content of <100 ppm and high-purity Si with a purity of >6N and an oxygen content of <50 ppm are prepared, and the corresponding weights of high-purity molybdenum and high-purity silicon are weighed according to the atomic ratio Mo:Si = 3:1.

[0104] 2. Melting: Melting is performed twice, and high-purity Ar gas is introduced during each melting to prevent Si volatilization. The melting temperature is 2400°C, and then a Mo3Si alloy ingot with a purity of 5N, an oxygen content of 79 ppm, and a Si composition fluctuation of ±0.8 at.% is formed by pouring.

[0105] 3. Pickling: The obtained Mo3Si alloy ingot is pickled to remove the surface oxide scale of the ingot, and a high-purity Mo3Si alloy powder rod is obtained.

[0106] 4. Powdering: In order to prevent the high-purity Mo3Si alloy from reacting with the powdering crucible during the powdering process and introducing impurities, the obtained high-purity Mo3Si alloy powdering rod is loaded into a crucible-free powdering furnace for powdering, and the powdering gas pressure is 1 MPa. Finally, spherical Mo3Si alloy powder with a purity of 4N5, an oxygen content of 95 ppm, and a particle size of ≤2 μm is obtained.

[0107] Screening: The obtained high-purity Mo3Si powder is screened to obtain spherical Mo3Si alloy powder with a particle size of 0.5-1.5 μm.

[0108] 5. Powder mixing: According to the composition requirement of the MoSi alloy target with a Si content of ≤25 wt%, the obtained 0.5-1.5 μm spherical Mo3Si alloy powder is mixed with elemental spherical Mo powder with a purity of >4N after being proportioned. MoSi alloy powder is obtained.

[0109] 6. Hot-pressing sintering: The obtained high-purity MoSi alloy powder is loaded into a vacuum hot-pressing furnace for hot-pressing. Finally, a high-purity molybdenum-silicon alloy target with a Si content of ≤25 wt%, a size of 350 mm, a purity of 4N1, a density of 97.2%, an average grain size of 5 μm, a whole target surface Si content composition fluctuation of ±0.6 wt%, and an oxygen content of 75 ppm is obtained. The hot-pressing temperature is 1000°C, the hot-pressing pressure is 10 MPa, and the hot-pressing time is 1 h.

[0110] Comparative Example 14

[0111] 1. Weighing: High-purity molybdenum with a purity of >3N5 and an oxygen content of <100 ppm and high-purity Si with a purity of >6N and an oxygen content of <50 ppm are prepared, and the corresponding weights of high-purity molybdenum and high-purity silicon are weighed according to the atomic ratio Mo:Si = 3:1.

[0112] 2. Melting: Melting is performed twice, and high-purity Ar gas is introduced during each melting to prevent Si volatilization. The melting temperature is 2400°C, and then a Mo3Si alloy ingot with a purity of 5N, an oxygen content of 79 ppm, and a Si composition fluctuation of ±0.8 at.% is formed by pouring.

[0113] 3. Pickling: The obtained Mo3Si alloy ingot is pickled to remove the surface oxide scale, and a high-purity Mo3Si alloy powdering rod is obtained.

[0114] 4. Powdering: In order to prevent the high-purity Mo3Si alloy from reacting with the powdering crucible during the powdering process and introducing impurities, the obtained high-purity Mo3Si alloy powdering rod is loaded into a crucible-free powdering furnace for powdering, and the powdering gas pressure is 2 MPa. Finally, spherical Mo3Si alloy powder with a purity of 4N5, an oxygen content of 95 ppm, and a particle size of ≤2 μm is obtained.

[0115] Screening: The obtained high-purity Mo3Si powder is screened to obtain spherical Mo3Si alloy powder with a particle size of 0.5-1.5 μm.

[0116] 5. Mixing powder: The obtained 0.5-1.5 μm spherical Mo3Si alloy powder is mixed with elemental spherical Mo powder with a purity of >4N after being proportioned according to the MoSi alloy target component requirement of Si content ≤25wt% to obtain MoSi alloy powder.

[0117] 6. Hot-pressing sintering: The obtained high-purity MoSi alloy powder is loaded into a vacuum hot-pressing furnace for hot-pressing to finally obtain a high-purity molybdenum-silicon alloy target with a Si content of ≤25wt%, a size of 350mm, a purity of 4N1, a density of 98.6%, an average grain size of 5 μm, a whole target surface Si content component fluctuation of ±0.6wt%, and an oxygen content of 75ppm. The hot-pressing temperature is 1000℃, the hot-pressing pressure is 10MPa, and the hot-pressing time is 1h.

[0118] The main manufacturing process and performance results of the molybdenum-silicon alloy targets in Examples 1-8 and Comparative Examples 1-14 are shown in Tables 1, 2 and 3.

[0119] Table 1 Main manufacturing process and performance of molybdenum-silicon alloy targets of examples

[0120]

[0121] Table 2 Main manufacturing process and performance of molybdenum-silicon alloy targets of comparative examples 1-8

[0122]

[0123] Table 3 Main manufacturing process and performance of molybdenum-silicon alloy targets of comparative examples 9-14

[0124]

[0125]

[0126] As can be seen from the above table, compared with Comparative Examples 1-4, the molybdenum-silicon alloy targets of Examples 1-8 have no cracks, but the molybdenum-silicon alloy targets of Comparative Examples 1-4 have cracks, which shows that the sintering method of mixing Mo3Si alloy powder with elemental Mo powder used in the present application can effectively avoid the exothermic reaction in the sintering process of mixing elemental molybdenum powder with elemental silicon powder, thereby avoiding the cracking phenomenon of large-size targets.

[0127] Table 4 Main manufacturing process and performance of molybdenum-silicon alloy targets

[0128]

[0129] Example 5 and Comparative Example 1, under the same sintering process, the Mo3Si alloy powder prepared by the specific method in Example 5 is first prepared and then hot-pressed with Mo powder to obtain a molybdenum-silicon alloy target, the purity of which is 4N1 and the oxygen content is 70 ppm, while in Comparative Example 1, the molybdenum-silicon alloy target is obtained by directly mixing Mo powder and Si powder, the purity of which is 3N and the oxygen content is 940 ppm. Compared with Example 5, the purity and oxygen content of the molybdenum-silicon alloy target in Comparative Example 1 are reduced by 1-2 orders of magnitude, and the difference is significant.

[0130] The average grain size of the finished molybdenum-silicon alloy target in Example 5 is only 8 μm, which is about 5-6 times larger than that in Comparative Example 1. The large grain size of the target leads to poor uniformity of the thin film in the later sputtering process.

[0131] In addition, the Si content fluctuation of the target prepared in Example 5 is controlled within ±0.6 wt.%, while the Si content fluctuation of the finished target in Comparative Example 1 is twice that of Example 5. The difference in the content of the target components leads to deviation in the later sputtering process.

[0132] In addition, cracks appear on the surface of the finished target in Comparative Example 1, which cannot be used as a qualified target.

[0133] Table 5 Main manufacturing process and performance of molybdenum-silicon alloy target

[0134]

[0135] Example 5 and Comparative Example 5, Comparative Example 5 obtains a molybdenum-silicon alloy target with a purity of 3N and an oxygen content of 930 ppm, which shows that the method of preparing high-purity spherical powder by melting elemental molybdenum and elemental silicon in the present patent can effectively improve the purity of the final molybdenum-silicon alloy target and reduce the oxygen content of the target.

[0136] In addition, under the same sintering process, Example 5 can obtain a molybdenum-silicon alloy target with a relative density of 99.97%, an average grain size of 8 μm, and a Si content fluctuation of ±0.6 wt.%, while Comparative Example 5 obtains a molybdenum-silicon alloy target with a relative density of 98.65%, an average grain size of 30 μm, and a Si content fluctuation of ±0.8 wt.%. Comparative Example 1 and Comparative Example 5 only differ in morphology. The powder prepared by the present patent is spherical, while the powder in Comparative Example 5 is polygonal. This shows that compared with the method of preparing polygonal powder by ball milling, the method of preparing spherical alloy powder can effectively improve the flowability of the powder, and obtain a molybdenum-silicon alloy target with higher density, finer grain size, and more uniform composition.

[0137] Table 6 Main manufacturing process and performance of molybdenum-silicon alloy target

[0138]

[0139] Compared with Comparative Example 9, the same powder preparation process and sintering process, the MoSi alloy target material with purity of 4N1 and oxygen content of 75 ppm can be obtained in Example 1, while the MoSi alloy target material with purity of 4N and oxygen content of 90 ppm can be obtained in Comparative Example 9, which indicates that the target material with higher purity can be obtained in Example 1 by melting for more times. However, in Comparative Example 9, the Si component fluctuation is significantly increased (about 3 times higher than that in Example 1), which is easy to cause the component deviation in the later target material use process and reduce the sputtering product effect.

[0140] However, compared with Comparative Example 10, the same powder preparation process and sintering process, the MoSi alloy target material with purity of 4N2 and oxygen content of 62 ppm can be obtained in Example 3 by melting for 5 times, while the MoSi alloy target material with purity of 4N2 and oxygen content of 62 ppm can be obtained in Comparative Example 10 by melting for 6 times, but the preparation process is significantly increased and the cost is significantly increased due to the more melting times.

[0141] In addition, compared with Comparative Example 9, the same powder preparation process and sintering process, the MoSi alloy target material with Si component fluctuation of ±0.6 wt.% can be obtained in Example 1, while the MoSi alloy target material with Si component fluctuation of ±1.8 wt.% can be obtained in Comparative Example 9, which indicates that the target material with more uniform component can be obtained by melting for more times. However, compared with Comparative Example 10, the same powder preparation process and sintering process, the MoSi alloy target material with Si component fluctuation of ±0.4 wt.% can be obtained in Example 3 by melting for 5 times, while the MoSi alloy target material with Si component fluctuation of ±0.4 wt.% can be obtained in Comparative Example 10 by melting for 6 times, which indicates that the effect of increasing the component uniformity is not obvious when the melting times are more than 5 times.

[0142] Table 7 Main manufacturing process and performance of MoSi alloy target material

[0143]

[0144] It can be seen from Example 1 and Comparative Example 11 that when the melting temperature is lower than 2400℃, the MoSi alloy ingot cannot be melted and the subsequent target material cannot be prepared.

[0145] It can be seen from the comparison between Example 1 and Comparative Example 12 that, under the same powdering process and sintering process conditions, when the smelting temperature is greater than 2500°C, the molybdenum silicon alloy target with a Si component fluctuation of ±0.6wt.% can be obtained in Example 1, while the molybdenum silicon alloy target with a Si component fluctuation of ±3.5wt.% can be obtained in Comparative Example 12 (about 8 times higher than Comparative Example 1, and the Si component fluctuation is significantly increased). This is because the smelting temperature is too high, and the Si component is prone to volatilize during smelting, thereby resulting in a large Si component fluctuation.

[0146] Table 8 Main manufacturing process and performance of molybdenum silicon alloy target

[0147]

[0148]

[0149] It can be seen from the comparison between Example 1 and Comparative Examples 13 and 14 that, under the same smelting process and sintering process conditions, the molybdenum silicon alloy target with a relative density of 99.95% can be obtained in Example 1 with a powdering gas pressure of 2MPa, while the molybdenum silicon alloy target with a relative density of only 97.2% can be obtained in Example 1 with a powdering gas pressure of 1MPa, and the molybdenum silicon alloy target with a relative density of only 98.6% can be obtained in Example 1 with a powdering gas pressure of 4MPa. This is because when the powdering gas pressure is less than 2MPa, hollow sphere powder and irregularly shaped powder are prone to be formed, and when the powdering gas pressure is greater than 3MPa, satellite sphere powder is formed. The hollow sphere powder cannot obtain a relatively dense target after pressing and sintering, and the satellite sphere powder cannot obtain a relatively dense target either due to the poor flowability of the powder particles with a large size difference.

Claims

1. A method for preparing a high-purity, high-uniformity, low-oxygen molybdenum-silicon alloy target material, comprising the following steps: (1) preparing raw materials: high-purity molybdenum (Mo) and high-purity silicon (Si) are prepared according to the atomic ratio of Mo:Si = 3:1; the purity of the high-purity Mo is greater than 3N5, and the oxygen content is less than 100 ppm; the purity of the high-purity Si is greater than 6N, and the oxygen content is less than 50 ppm; (2) after the high-purity Mo and the high-purity Si are prepared, the Mo3Si alloy ingot is obtained by casting after melting; in the step (2), the melting temperature is 2400-2500℃; the melting is performed 2-5 times; inert gas is used as the protective gas during the melting; (3) the Mo3Si alloy ingot is pickled to remove the oxide skin on the surface of the ingot, and a Mo3Si alloy powder rod is obtained; (4) the Mo3Si alloy powder rod is powdered in a crucible-free powdering furnace, and a Mo3Si alloy powder is obtained; in the step (4), the powdering pressure is 2-3 MPa; (5) the Mo3Si alloy powder and Mo powder with a spherical morphology are put into a powder mixing tank to mix the powders, and a MoSi alloy powder is obtained; (6) the MoSi alloy powder is vacuum hot-pressed and sintered to obtain a molybdenum-silicon alloy target material; the purity of the molybdenum-silicon alloy target material is greater than or equal to 4N, the Si content is less than or equal to 25 wt%, the oxygen content is less than or equal to 100 ppm, and the balance is Mo. In the step (4), the particle size of the Mo3Si alloy powder is less than or equal to 2 μm. wherein In the step (4), the Mo3Si alloy powder has a spherical morphology. In the step (4), the purity of the Mo3Si alloy powder is greater than or equal to 4N5, and the oxygen content is less than or equal to 100 ppm. In the step (4), the particle size of the Mo3Si alloy powder is 0.5-1.5 μm. In the step (2), the purity of the Mo3Si alloy ingot is greater than or equal to 5N, the oxygen content is less than or equal to 80 ppm, and the Si content fluctuation is less than or equal to ±1 at.%. In the step (5), the purity of the Mo powder is greater than 4N. The size of the molybdenum-silicon alloy target material is greater than or equal to 300 mm. The density of the molybdenum-silicon alloy target material is greater than or equal to 99.5%, and the average grain size is less than or equal to 20 μm. The Si content fluctuation of the molybdenum-silicon alloy target material is less than or equal to ±0.5 wt%. The temperature of the vacuum hot-pressing and sintering is 1000-1400℃.

2. The method for preparing a high-purity, highly uniform, low-oxygen molybdenum-silicon alloy target according to claim 1, wherein, The pressure of the vacuum hot-pressing and sintering is 10-30 MPa. The time of the vacuum hot-pressing and sintering is 1-6 h. The vacuum hot-pressing and sintering process is performed in a vacuum hot-pressing furnace.

3. The method for preparing a high-purity, highly uniform, low-oxygen molybdenum-silicon alloy target according to claim 2, wherein, 13.A high-purity, high-uniformity, low-oxygen molybdenum-silicon alloy target material prepared by the method of any one of claims 1-12.

4. The method for preparing a high-purity, highly uniform, low-oxygen molybdenum-silicon alloy target according to claim 1, wherein, ​ 5. The method for preparing a high-purity, highly uniform, low-oxygen molybdenum-silicon alloy target according to claim 1, wherein, ​ 6. The method for preparing a high-purity, highly uniform, low-oxygen molybdenum-silicon alloy target according to claim 1, wherein, ​ 7. The method for preparing a high-purity, highly uniform, low-oxygen molybdenum-silicon alloy target according to claim 1, wherein, ​ 8. The method for preparing a high-purity, highly uniform, low-oxygen molybdenum-silicon alloy target according to claim 1, wherein, ​ 9. The method for preparing a high-purity, highly uniform, low-oxygen molybdenum-silicon alloy target according to claim 1, wherein, ​ 10. The method for preparing a high-purity, highly uniform, low-oxygen molybdenum-silicon alloy target according to claim 1, wherein, ​ 11. The method for preparing a high-purity, highly uniform, low-oxygen molybdenum-silicon alloy target according to claim 1, wherein, ​ 12. The method for preparing a high-purity, highly uniform, low-oxygen molybdenum-silicon alloy target according to claim 1, wherein, ​ ​

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