Highly Dispersed Spherical Iridium Powder with a Particle Size Less than 1 μm, Its Preparation Method and Application

Abstract

The present invention discloses high-dispersion spherical iridium powder with a particle size less than 1 μm, its preparation method and application, solving the problem of preparing high-dispersion spherical iridium powder with uniform and fine particle size and controllable particle size. When preparing the iridium powder, a high-dispersion spherical precursor precipitate powder with controllable particle size is obtained by regulating the molar ratio of sulfate ions to iridium ions in the solution, and then the precursor precipitate powder is calcined in a hydrogen atmosphere to obtain high-dispersion spherical iridium powder with a particle size less than 1 μm. The technology of the present invention is novel, and the preparation method has low energy consumption, is environmentally friendly and has a simple process, can realize the large-scale preparation of high-dispersion spherical iridium powder with a particle size less than 1 μm, and the material prepared by this method has broad application prospects in the field of semiconductor sputtering targets.

Description

Technical Field

[0001] The present invention relates to high-dispersion spherical iridium powder with a particle size less than 1 μm, its preparation method and application, belonging to the fields of precious metals and semiconductor sputtering targets. Background Art

[0002] With the rapid development of the electronic information industry, precious metal iridium, as a special electronic material with high added value, in technical fields such as information storage, microelectronics, and new energy, different iridium-based targets are used to sputter various iridium-based thin films by magnetron sputtering to meet the magnetic, electrical, optical, piezoelectric and other performance requirements of products. With the miniaturization and structural complexity of modern microelectronic devices, the thin films on the devices usually require higher uniformity, and at the same time, it is necessary to improve the sputtering rate of the sputtering process. The improvement of the microstructure of the sputtering target is the key to improving the sputtering rate and the uniformity of the sputtered thin film. For precious metal iridium-based sputtering targets, their preparation methods basically adopt powder metallurgy technology, and the performance of the raw material powder affects the performance of the final sputtering target. Spherical powder is easy to form a higher packing density and is easy to obtain a higher density during subsequent forming and sintering processes. Uniform and fine grains in the target can improve the sputtering rate and coating uniformity of the target, so there is a greater need for raw material powder with a small particle size and a uniform distribution. At present, the preparation of high-dispersion spherical iridium powder with a uniform and fine particle size is one of the technical bottlenecks in the preparation of high-performance targets.

[0003] Generally, iridium powder at home and abroad is generally prepared by chemical methods, that is, the iridium-containing material is subjected to secondary oxidation distillation, concentrated and crystallized to obtain iridium trichloride, and the iridium trichloride is reduced by hydrogen to prepare iridium powder, or the iridium-containing absorption solution is oxidized and then ammonium chloride or ammonium sulfide is added for precipitation, and after precipitation, it is calcined, hydrogen-reduced and other processes to prepare iridium powder. The iridium powder prepared by the above methods has a high impurity content, irregular powder morphology, easy agglomeration, and a wide powder particle size distribution range. It is difficult to meet the forming and densification requirements of the target, and it is also not conducive to the control and uniformity of the grain size and its distribution of the target.

[0004] With the demand for iridium powder raw materials for sputtering targets in the development of technology and industry, there is an urgent need to develop a preparation method for high-dispersion spherical iridium powder with a controllable and uniform fine particle size. The existing technology cannot solve this technical problem. The present invention provides a preparation method for high-dispersion spherical iridium powder with a particle size less than 1 μm, and solves the problem of high-performance raw material powder required for the preparation of high-performance iridium sputtering targets. Summary of the Invention

[0005] In order to solve the deficiencies in the existing technology, the present invention proposes to regulate the concentration ratio of sulfate ions to iridium ions in the solution, and then regulate the morphology, particle size and size of the precipitated powder, and then combine high-temperature calcination with hydrogen to obtain high-dispersion spherical iridium powder. Its technology is novel, and high-dispersion spherical iridium powder with a particle size less than 1 μm is successfully prepared. The present invention is an important technological innovation.

[0006] The present invention provides highly dispersed spherical iridium powder with a particle size less than 1 μm, a preparation method thereof, and an application thereof. The characteristics are that the iridium powder includes Class I iridium powder, Class II iridium powder, Class III iridium powder, Class IV iridium powder, and Class V iridium powder:

[0007] When preparing the Class I iridium powder, the molar ratio of sulfate ions to iridium ions in the reaction solution is 0.5 - 1, and a highly dispersed spherical precursor precipitate powder is obtained through the urea homogeneous precipitation process. The particle size range of the powder is 0.1 - 0.15 μm;

[0008] When preparing the Class II iridium powder, the molar ratio of sulfate ions to iridium ions in the reaction solution is 1 - 1.5, and a highly dispersed spherical precursor precipitate powder is obtained through the urea homogeneous precipitation process. The particle size range of the powder is 0.1 - 0.2 μm;

[0009] When preparing the Class III iridium powder, the molar ratio of sulfate ions to iridium ions in the reaction solution is 1.5 - 2, and a highly dispersed spherical precursor precipitate powder is obtained through the urea homogeneous precipitation process. The particle size range of the powder is 0.1 - 0.25 μm;

[0010] When preparing the Class IV iridium powder, the molar ratio of sulfate ions to iridium ions in the reaction solution is 2 - 5, and a highly dispersed spherical precursor precipitate powder is obtained through the urea homogeneous precipitation process. The particle size range of the powder is 0.2 - 0.5 μm;

[0011] When preparing the Class V iridium powder, the molar ratio of sulfate ions to iridium ions in the reaction solution is 5 - 10, and a highly dispersed spherical precursor precipitate powder is obtained through the urea homogeneous precipitation process. The particle size range of the powder is 0.24 - 0.6 μm;

[0012] The above highly dispersed spherical precursor precipitate powders are respectively calcined at high temperature in a hydrogen atmosphere to obtain highly dispersed spherical iridium powder with a particle size less than 1 μm.

[0013] Furthermore, in the above technical solution, when preparing the Class I - V iridium powders, a reaction solution containing iridium ions and sulfate ions is configured, urea is added to the reaction solution, the solution is homogenized at room temperature, and then the temperature is raised for reaction to generate a precipitate under stirring. After cooling, the precipitate is filtered, washed, and dried to obtain a highly dispersed spherical precursor precipitate powder; the particle size range of the highly dispersed spherical precursor precipitate powder is 0.1 - 0.6 μm. The highly dispersed spherical precursor precipitate powder is calcined in a hydrogen atmosphere to obtain spherical iridium powder with a particle size less than 1 μm.

[0014] Furthermore, in the above technical solution, the concentration of iridium ions in the reaction solution is 0.0001 - 0.1 mol / L; preferably 0.0005 - 0.005 mol / L; more preferably 0.0005 - 0.001 mol / L, and the molar ratio of sulfate ions to iridium ions is 0.5 - 10.

[0015] Further, in the above technical solution, the molar ratio of urea to iridium ions is 1 - 50; preferably 10 - 45; more preferably 20 - 30, the homogenization treatment time is 1 - 2 h, the temperature for the precipitation reaction is 80 - 100 °C; preferably 80 - 95 °C; more preferably 85 - 90 °C, and the precipitation reaction time is 120 - 600 min; preferably 120 - 480 min; more preferably 240 - 300 min.

[0016] Further, in the above technical solution, in the high-temperature calcination process of hydrogen, the calcination temperature is 250 - 800 °C; preferably 250 - 700 °C; more preferably 250 - 450 °C, and the calcination time is 30 - 300 min; preferably 30 - 240 min; more preferably 30 - 120 min.

[0017] Further, in the above technical solution, the iridium ions are selected from one or more of iridium trichloride, iridium tetrachloride, ammonium hexachloroiridate, and iridium acetate.

[0018] Further, in the above technical solution, the sulfate ions are selected from one or more of sulfuric acid, ammonium sulfate, and ammonium bisulfate.

[0019] The present invention provides high-dispersion spherical iridium powder with a particle size of less than 1 μm obtained by the above method. The iridium powder is spherical, with a particle size of less than 1 μm, a narrow particle size distribution range, highly dispersed particle sizes, and controllability.

[0020] The present invention provides the above iridium powder, which can be used as a raw material for sputtering targets in the field of information storage.

[0021] Advantages of the Invention

[0022] The preparation of high-dispersion spherical iridium powder with uniform and fine particle sizes is one of the technical bottlenecks in the preparation of high-performance iridium targets. The present invention provides a method for preparing high-dispersion spherical iridium powder with a particle size of less than 1 μm, solving the problem of high-performance raw material powder required for the preparation of high-performance iridium sputtering targets. The prepared iridium powder has a particle size of less than 1 μm, is spherical, has controllable particle size dimensions, a narrow particle size distribution range, and is highly dispersed. Description of the Drawings

[0023] Figure 1 SEM morphology diagram of the iridium precursor precipitation powder prepared in Comparative Example 1;

[0024] Figure 2 SEM morphology diagram of the iridium powder prepared in Comparative Example 1;

[0025] Figure 3 XRD pattern of the iridium powder prepared in Comparative Example 1;

[0026] Figure 4SEM morphology diagram of the iridium precursor precipitate powder prepared in Example 1;

[0027] Figure 5 SEM morphology diagram of the iridium powder prepared in Example 1;

[0028] Figure 6 XRD pattern of the iridium powder prepared in Example 1;

[0029] Figure 7 SEM morphology diagram of the iridium precursor precipitate powder prepared in Example 2;

[0030] Figure 8 SEM morphology diagram of the iridium powder prepared in Example 2;

[0031] Figure 9 XRD pattern of the iridium powder prepared in Example 2;

[0032] Figure 10 SEM morphology diagram of the iridium precursor precipitate powder in Example 3;

[0033] Figure 11 SEM morphology diagram of the iridium powder prepared in Example 3;

[0034] Figure 12 XRD pattern of the iridium powder prepared in Example 3. Detailed implementation mode

[0035] The present invention will be further described below through examples. The following examples are only for understanding the present invention and do not limit the present invention.

[0036] Comparative Example 1

[0037] 1. Dissolve 0.1495 g of iridium trichloride in 400 mL of deionized water to prepare an iridium ion-containing solution.

[0038] 2. Dissolve 0.7575 g of urea in 400 mL of deionized water to prepare a urea solution, then mix the iridium ion-containing solution with the urea solution, and then add deionized water to make up the volume to 1000 mL to obtain a 1 L mixed solution with an iridium(III) chloride concentration of 0.0005 M and a urea concentration of 0.0125 M.

[0039] 3. After homogenizing the mixed solution for 2 h, place it in a constant temperature water bath and heat it to 80 °C for reaction for 9 h, with a rotation speed of 240 r / min. After the reaction, cool it naturally to room temperature. Centrifuge to collect the product, wash it three times with deionized water and absolute ethanol respectively, and then dry it under an infrared lamp for 2 h to obtain the precursor precipitate powder. The morphology of the obtained precursor precipitate powder is as Figure 1 shown. The powder morphology is spherical, and the particle size distribution range of the powder is 0.12 - 0.34 μm.

[0040] 4. Finally, place the precursor precipitate powder in a corundum crucible and calcine it in a hydrogen furnace at 250 °C under a hydrogen atmosphere for 30 min to obtain Figure 2 spherical iridium powder with a particle size less than 1 μm and a distribution range of 0.05 - 0.13 μm. Its XRD pattern is as Figure 3 shown.

[0041] Example 1

[0042] 1. Dissolve 0.1495 g of iridium(III) chloride in 400 mL of deionized water to prepare an iridium ion-containing solution, and dissolve 2.5 ml of 0.1 mol / L sulfuric acid solution in 400 mL of deionized water to prepare a sulfate ion-containing solution.

[0043] 2. Mix the iridium ion-containing solution with the sulfate ion-containing solution, and the molar ratio of sulfate ions to iridium ions in the solution is 0.5:1. Add 0.7575 g of urea to the mixed solution, and then add deionized water to make up the volume to 1000 mL to obtain a 1 L mixed solution with a concentration of iridium(III) chloride of 0.0005 M and a concentration of urea of 0.0125 M.

[0044] 3. After homogenizing the mixed solution for 2 h, place it in a constant temperature water bath and heat it to 80 °C for reaction for 9 h, with a rotation speed of 240 r / min. After the reaction, cool it naturally to room temperature. Centrifuge to collect the product, wash it three times with deionized water and anhydrous ethanol respectively, and then dry it under an infrared lamp for 2 h to obtain the precursor precipitate powder. The morphology of the obtained precursor precipitate powder is as Figure 4 shown. The powder morphology is spherical, and the particle size distribution range of the powder is 0.1 - 0.15 μm.

[0045] 4. Finally, place the precursor precipitate powder in a corundum crucible and calcine it in a hydrogen furnace at 250 °C under a hydrogen atmosphere for 30 min to obtain Figure 5 spherical iridium powder with a particle size less than 1 μm and a distribution range of 0.02 - 0.15 μm. Its XRD pattern is as Figure 6 shown.

[0046] Example 2

[0047] 1. Dissolve 0.1495 g of iridium(III) chloride in 400 mL of deionized water to prepare an iridium ion-containing solution, and dissolve 0.3304 g of ammonium sulfate and 2.5 mL of 0.1 mol / L sulfuric acid solution in 400 mL of deionized water to prepare a sulfate ion-containing solution.

[0048] 2. Mix the iridium ion-containing solution with the sulfate ion-containing solution so that the molar ratio of sulfate ions to iridium ions in the solution is 1:1. Add 0.7575 g of urea to the mixed solution, and then add deionized water to make the volume up to 1000 mL to obtain a 1 L mixed solution with a concentration of iridium(III) chloride of 0.0005 M and a concentration of urea of 0.0125 M.

[0049] 3. After homogenizing the mixed solution for 2 h, place it in a constant temperature water bath and heat it to 85 °C for reaction for 8 h at a rotation speed of 360 r / min. After the reaction, cool it naturally to room temperature. Centrifuge to collect the product, wash it three times with deionized water and anhydrous ethanol respectively, and then dry it under an infrared lamp for 2 h to obtain the precursor precipitate powder. The morphology of the obtained precursor precipitate powder is as Figure 7 shown. The powder morphology is spherical, and the particle size distribution range of the powder is 0.1 - 0.2 μm.

[0050] 4. Finally, place the precursor precipitate powder in a corundum crucible and calcine it in a hydrogen furnace at 250 °C under a hydrogen atmosphere for 40 min to obtain spherical iridium powder with a particle size less than 1 μm and a distribution range of 0.03 - 0.2 μm. Its XRD pattern is as Figure 8 shown. Figure 9 shown.

[0051] Example 3

[0052] 1. Dissolve 0.1495 g of iridium(III) chloride in 400 mL of deionized water to prepare an iridium ion-containing solution, and dissolve 0.6608 g of ammonium sulfate and 2.5 mL of 0.1 mol / L sulfuric acid solution in 400 mL of deionized water to prepare a sulfate ion-containing solution.

[0053] 2. Mix the iridium ion-containing solution with the sulfate ion-containing solution so that the molar ratio of sulfate ions to iridium ions in the solution is 1.5:1. Add 0.7575 g of urea to the mixed solution, and then add deionized water to make the volume up to 1000 mL to obtain a 1 L mixed solution with a concentration of iridium(III) chloride of 0.0005 M and a concentration of urea of 0.0125 M.

[0054] 3. After homogenizing the mixed solution for 2 h, place it in a constant temperature water bath and heat it to 90 °C for reaction for 7 h at a rotation speed of 420 r / min. After the reaction, cool it naturally to room temperature. Centrifuge to collect the product, wash it three times with deionized water and anhydrous ethanol respectively, and then dry it under an infrared lamp for 2 h to obtain the precursor precipitate powder. The morphology of the obtained precursor precipitate powder is as Figure 10 shown. The powder morphology is spherical, and the particle size distribution range of the powder is 0.1 - 0.25 μm.

[0055] 4. Finally, place the precursor precipitate powder in a corundum crucible and calcine it in a hydrogen furnace at 450 °C under a hydrogen atmosphere for 50 min to obtain as Figure 11Spherical iridium powder with a particle size less than 1 μm and a distribution range of 0.03 - 0.25 μm, and its XRD pattern is as Figure 12 shown.

[0056] Example 4

[0057] 1. Dissolve 0.1495 g of iridium trichloride in 400 mL of deionized water to prepare an iridium ion-containing solution, and dissolve 0.9912 g of ammonium sulfate and 0.0288 g of ammonium bisulfate in 400 mL of deionized water to prepare a sulfate ion-containing solution.

[0058] 2. Mix the iridium ion-containing solution and the sulfate ion-containing solution, and the molar ratio of sulfate ions to iridium ions in the solution is 2:1. Add 1.515 g of urea to the mixed solution, and then add deionized water to make the volume up to 1000 mL to obtain a 1 L mixed solution with a concentration of iridium(III) chloride of 0.0005 M and a urea concentration of 0.025 M.

[0059] 3. After homogenizing the mixed solution for 2 h, place it in a constant temperature water bath and heat it to 90 °C for reaction for 7 h, with a rotation speed of 420 r / min. After the reaction, cool it naturally to room temperature. Centrifuge to collect the product, wash it three times with deionized water and anhydrous ethanol respectively, and then dry it under an infrared lamp for 2 h to obtain a precursor precipitate powder. The obtained precursor precipitate powder has a spherical morphology, and the particle size distribution range of the powder is 0.2 - 0.5 μm.

[0060] 4. Finally, place the precursor precipitate powder in a corundum crucible and calcine it in a hydrogen furnace at 350 °C under a hydrogen atmosphere for 80 min to obtain spherical iridium powder with a particle size less than 1 μm.

[0061] Example 5

[0062] 1. Dissolve 1.6702 g of iridium tetrachloride in 400 mL of deionized water to prepare an iridium ion-containing solution, and dissolve 3.304 g of ammonium sulfate in 400 mL of deionized water to prepare a sulfate ion-containing solution.

[0063] 2. Mix the iridium ion-containing solution and the sulfate ion-containing solution, and the molar ratio of sulfate ions to iridium ions in the solution is 5:1. Add 9.09 g of urea to the mixed solution, and then add deionized water to make the volume up to 1000 mL to obtain a 1 L mixed solution with a concentration of iridium(IV) chloride of 0.005 M and a urea concentration of 0.15 M.

[0064] 3. After homogenizing the mixed solution for 2 h, it was placed in a constant temperature water bath and heated to 100 °C for reaction for 5 h at a rotation speed of 480 r / min. After the reaction, it was naturally cooled to room temperature. The product was collected by centrifugation, washed three times with deionized water and anhydrous ethanol respectively, and then dried under an infrared lamp for 2 h to obtain the precursor precipitate powder. The obtained precursor precipitate powder was spherical in shape, and the particle size distribution range of the powder was 0.24 - 0.6 μm.

[0065] 4. Finally, the precursor precipitate powder was placed in a corundum crucible and calcined in a hydrogen furnace at 550 °C in a hydrogen atmosphere for 110 min to obtain spherical iridium powder with a particle size less than 1 μm.

[0066] Example 6

[0067] 1. 0.1102 g of ammonium hexachloroiridate(IV) and 0.2726 g of iridium(III) acetate were dissolved in 400 mL of deionized water to prepare an iridium ion-containing solution, and 50 ml of 0.1 mol / L sulfuric acid solution was dissolved in 400 mL of deionized water to prepare a sulfate ion-containing solution.

[0068] 2. The iridium ion-containing solution and the sulfate ion-containing solution were mixed, and the molar ratio of sulfate ions to iridium ions in the solution was 10:1. 0.606 g of urea was added to the mixed solution, and then deionized water was added to make the volume up to 1000 mL to obtain a 1 L mixed solution with an iridium ion concentration of 0.0005 M and a urea concentration of 0.01 M.

[0069] 3. After homogenizing the mixed solution for 2 h, it was placed in a constant temperature water bath and heated to 80 °C for reaction for 9 h at a rotation speed of 240 r / min. After the reaction, it was naturally cooled to room temperature. The product was collected by centrifugation, washed three times with deionized water and anhydrous ethanol respectively, and then dried under an infrared lamp for 2 h to obtain the precursor precipitate powder. The obtained precursor precipitate powder was spherical in shape, and the particle size distribution range of the powder was 0.24 - 0.6 μm.

[0070] 4. Finally, the precursor precipitate powder was placed in a corundum crucible and calcined in a hydrogen furnace at 650 °C in a hydrogen atmosphere for 30 min to obtain spherical iridium powder with a particle size less than 1 μm.

Claims

1. Preparation method of highly dispersed spherical iridium powder with particle size less than 1 μm Characterized in that The iridium powder includes Class I iridium powder, Class II iridium powder, Class III iridium powder, Class IV iridium powder, and Class V iridium powder: When preparing the Class I iridium powder, the molar ratio of sulfate ions to iridium ions in the reaction solution is 0.5 - 1, and a highly dispersed spherical precursor precipitate powder is obtained through the urea homogeneous precipitation process. The particle size range of the precursor precipitate powder is 0.1 - 0.15 μm; When preparing the Class II iridium powder, the molar ratio of sulfate ions to iridium ions in the reaction solution is 1 - 1.5, and a highly dispersed spherical precursor precipitate powder is obtained through the urea homogeneous precipitation process. The particle size range of the precursor precipitate powder is 0.1 - 0.2 μm; When preparing the Class III iridium powder, the molar ratio of sulfate ions to iridium ions in the reaction solution is 1.5 - 2, and a highly dispersed spherical precursor precipitate powder is obtained through the urea homogeneous precipitation process. The particle size range of the precursor precipitate powder is 0.1 - 0.25 μm; When preparing the Class IV iridium powder, the molar ratio of sulfate ions to iridium ions in the reaction solution is 2 - 5, and a highly dispersed spherical precursor precipitate powder is obtained through the urea homogeneous precipitation process. The particle size range of the precursor precipitate powder is 0.2 - 0.5 μm; When preparing the Class V iridium powder, the molar ratio of sulfate ions to iridium ions in the reaction solution is 5 - 10, and a highly dispersed spherical precursor precipitate powder is obtained through the urea homogeneous precipitation process. The particle size range of the precursor precipitate powder is 0.24 - 0.6 μm; The above-mentioned highly dispersed spherical precursor precipitate powders are respectively calcined at high temperature in a hydrogen atmosphere to obtain highly dispersed spherical iridium powder with particle size less than 1 μm.

2. The preparation method according to claim 1 Characterized in that: Prepare a reaction solution containing iridium ions and sulfate ions, add urea to the reaction solution, homogenize the solution at room temperature, then raise the temperature and react with stirring to form a precipitate. After cooling, filter, wash, and dry the precipitate to obtain a highly dispersed spherical precursor precipitate powder; the particle size range of the highly dispersed spherical precursor precipitate powder is 0.1 - 0.6 μm; calcine the highly dispersed spherical precursor precipitate powder in a hydrogen atmosphere to obtain spherical iridium powder with particle size less than 1 μm.

3. The preparation method according to claim 1 or 2 Characterized in that: The concentration of iridium ions in the reaction solution is 0.0001 - 0.1 mol / L, and the molar ratio of sulfate ions to iridium ions is 0.5 - 10.

4. The preparation method according to claim 1 or 2 Characterized in that: The molar ratio of urea to iridium ions is 1 - 50, the homogenization time is 1 - 2 h, the temperature for the precipitation reaction is 80 - 100 °C, and the time for the precipitation reaction is 120 - 600 min.

5. The preparation method according to claim 1 or 2 Characterized in that: In the high-temperature hydrogen calcination process, the calcination temperature is 250 - 800 °C, and the calcination time is 30 - 300 min.

6. The preparation method according to claim 1 or 2 Characterized in that: The iridium ions are selected from one or more of iridium trichloride, iridium tetrachloride, ammonium chloroiridate, and iridium acetate.

7. The preparation method according to claim 1 or 2 It is characterized in that: The sulfate ion is selected from one or more of sulfuric acid, ammonium sulfate, and ammonium bisulfate.

8. The high-dispersion spherical iridium powder with a particle size less than 1 μm obtained by the preparation method according to any one of claims 1-7.

9. The iridium powder according to claim 8, It is characterized in that: The iridium powder is spherical, with a particle size less than 1 μm, controllable particle size and narrow distribution range, and high dispersion.

10. The application of the iridium powder according to claim 9 in the field of semiconductor sputtering targets.

Images