Synthetic method of high-safety ruthenium hexafluoride

Abstract

The invention relates to a synthesis method of high-safety ruthenium hexafluoride, which comprises the following steps: S1, adding a raw material ruthenium into a reactor, evacuating, replacing and removing water and oxygen impurities under the purging of nitrogen or inert gas at 200-400 DEG C, and controlling the contents of water and oxygen to be lower than 5ppm; s2, under a high-temperature condition, introducing sulfur hexafluoride for cracking to generate fluoride of low-valence sulfur and fluorine gas; s3, the generated fluorine gas reacts with metal ruthenium in a reactor at the pressure of 0-1.0 MPa and the temperature of 550-750 DEG C, and ruthenium hexafluoride is generated; and S4, collecting ruthenium hexafluoride in a low-temperature collector, and collecting a ruthenium hexafluoride product with the purity of more than 99%. The method for preparing ruthenium hexafluoride is simple, and has the characteristics of controllable actual operation, few byproducts, controllable product quality and high product yield. The adopted raw material sulfur hexafluoride is odorless, non-toxic and non-combustible, so that the sulfur hexafluoride has very high safety, and the price of the sulfur hexafluoride is lower than that of other fluorides, so that the sulfur hexafluoride is widely favored. The method has the characteristics of high safety, low cost and good separation and purification effects.

Description

Technical Field

[0001] This application belongs to the technical field of semiconductor high-purity material preparation, specifically involving the synthesis, development, and preliminary purification technology of ruthenium hexafluoride. Background Technology

[0002] Ruthenium hexafluoride currently has unique applications as a strong oxidant and catalyst. In the semiconductor industry, it is used as an etchant to remove unwanted material layers from silicon wafers, ensuring high-precision pattern transfer during chip manufacturing.

[0003] Chinese patent CN120157196A relates to a method for synthesizing ruthenium hexafluoride. It includes the following steps: Step S1. Add metallic ruthenium to a reactor, heat it while purging the reactor with an inert gas, then evacuate it; repeat the purging and evacuation process. Step S2. Continue heating to 450–700°C, then introduce a mixture of fluorine and nitrogen gas, or nitrogen trifluoride, into the reactor to react with the metallic ruthenium to produce crude ruthenium hexafluoride. Finally, collect the refined ruthenium hexafluoride at low temperature. This application's method for preparing ruthenium hexafluoride is simple, practically controllable, produces few byproducts, has controllable product quality, and a high product yield, making it suitable for industrial production.

[0004] The above technology has the following drawbacks: the synthesis of ruthenium hexafluoride involves a chemical reaction under high temperature and high pressure conditions, and the ruthenium or its low-valence fluoride is synthesized by reaction. Due to the participation of excessive fluorine gas in the reaction, the reaction safety is low and by-products are easily generated. Summary of the Invention

[0005] To address safety concerns during the reaction process, a technique for synthesizing ruthenium hexafluoride by reacting sulfur hexafluoride with metallic ruthenium is provided. This application offers a highly safe method for synthesizing ruthenium hexafluoride, which achieves high technical safety, low raw material costs, few byproducts, and ease of purification and industrialization through the reaction of sulfur hexafluoride and metallic ruthenium under high temperature conditions.

[0006] This application provides a method for synthesizing highly safe ruthenium hexafluoride, which employs the following technical solution:

[0007] A method for synthesizing highly safe ruthenium hexafluoride includes the following steps:

[0008] S1. After adding ruthenium as the raw material to the reactor, the reactor is purged at 200-400°C with nitrogen or inert gas to remove water and oxygen impurities, and the water and oxygen content is controlled to be below 5 ppm.

[0009] S2. Under high temperature conditions, sulfur hexafluoride is introduced and cracked to produce low-valent sulfur fluorides and fluorine gas;

[0010] S3. The generated fluorine gas reacts with metallic ruthenium in a reactor at a pressure of 0–1.0 MPa and a temperature of 550–750 °C to generate ruthenium hexafluoride;

[0011] S4. Ruthenium hexafluoride is collected in a cryogenic collector at -70 to -10°C. Impurities are removed by low-temperature evacuation, and ruthenium hexafluoride products with a purity >99% are collected. Because ruthenium hexafluoride has a boiling point of 200°C and a freezing point of 54°C, its boiling point differs greatly from that of gaseous and metallic impurities, making it easy to separate.

[0012] Preferably, the moisture content of the inert gas used for S1 replacement and the sulfur hexafluoride gas used for S2 reaction is <5 ppm.

[0013] Preferably, the ruthenium used in S1 is in powder, granular, block, strip, or irregular shape, with a purity ≥95%.

[0014] Preferably, the S2 high-temperature conditions are 550–750°C and the pyrolysis reaction pressure is 0–1.0 MPa.

[0015] Preferably, the molar ratio of sulfur hexafluoride to ruthenium introduced into S2 is 1 to 2.5:1.

[0016] Preferably, the S3 reaction time is 5 to 25 minutes to ensure a complete reaction and avoid the formation of other fluoride states, and the flow rate is 250 mL to 1.5 L / min.

[0017] Preferably, the S4 collector removes impurities by low-temperature evacuation, with the pressure controlled at -0.1 to 0.1 MPa.

[0018] Preferably, the temperature at which the S4 collector removes impurities via low-temperature evacuation is -70 to -10°C.

[0019] Preferably, the reactor material is stainless steel, nickel, Monel alloy, or Hastelloy.

[0020] The beneficial technical effects of this application are:

[0021] This method for preparing ruthenium hexafluoride is simple, practically controllable, produces few byproducts, has controllable product quality, and a high yield. The raw material, sulfur hexafluoride, is highly safe due to its odorless, non-toxic, and non-flammable properties, and its lower price compared to other fluorides makes it widely favored. This application features high safety, low cost, and good separation and purification effects.

[0022] Because the ruthenium hexafluoride produced by the reaction has a high boiling point, it is easy to separate from impurities, and the process is easy to industrialize. The product is easy to purify, with few by-products and a large difference in boiling points between the product and by-products, making separation and purification easy and industrialization feasible. Detailed Implementation

[0023] Example 1

[0024] Examples of the synthesis of ruthenium hexafluoride according to the present invention are as follows:

[0025] S1. After adding ruthenium powder with a content of 98% into a stainless steel reactor, the system is evacuated and replaced three times under helium gas (containing water <0.5ppm) at 400℃ to remove water and oxygen and other impurities from the system.

[0026] S2.5 At a high temperature of 500℃, sulfur hexafluoride (containing <1ppm water) was introduced at a flow rate of 500mL / min to crack and generate fluorine gas, which reacted with strip-shaped ruthenium metal. The reaction pressure was controlled at 0MPa, and the molar ratio of sulfur hexafluoride to ruthenium was 1.5:1.

[0027] S3. The generated fluorine gas reacts with ruthenium in the reactor to form ruthenium hexafluoride. The pressure is 0 MPa, the temperature is 550℃, and the reaction time is 10 min to ensure a complete reaction without the formation of other fluoride states.

[0028] S4. Ruthenium hexafluoride is collected in a -30°C cryogenic collector. The collector is evacuated at low temperature to remove light component impurities from the gas and gas, and the light fluoride is recovered and reused. The pressure is controlled at 0 MPa. Ruthenium hexafluoride product with a purity of 99.9% can be collected, and the product yield is 90%.

[0029] Example 2

[0030] Examples of the synthesis of ruthenium hexafluoride according to the present invention are as follows:

[0031] S1. After adding 99% pure ruthenium metal to the nickel reactor, the system is evacuated and replaced 8 times under nitrogen gas (containing <1ppm water) at 200℃ to remove water and oxygen and other impurities.

[0032] Under high temperature conditions of 2.650℃, sulfur hexafluoride (containing <0.1ppm water) was introduced at a flow rate of 1.5L / min to crack and generate fluorine gas and react with irregular ruthenium metal blocks. The amount of sulfur hexafluoride introduced was 1.8 times that of ruthenium, and the reaction pressure was controlled at 0.1MPa.

[0033] S3. The generated fluorine gas reacts with ruthenium in the reactor to form ruthenium hexafluoride. The pressure is 0.5 MPa, the temperature is 750℃, and the reaction time is 12 min to ensure a complete reaction without the formation of other valence states of ruthenium fluoride.

[0034] S4. Ruthenium hexafluoride is collected in a -70°C cryogenic collector. The collector is evacuated at low temperature to remove light component impurities from the gas and gas mixture. The light fluoride is recycled and reused. The pressure is controlled at 0.1 MPa. The purity of ruthenium hexafluoride is 99%, and the yield is 90.5%.

[0035] Example 3

[0036] Examples of the synthesis of ruthenium hexafluoride according to the present invention are as follows:

[0037] S1. After adding 95.0% granular ruthenium metal to the Monel alloy reactor, the system was evacuated and replaced 8 times under nitrogen gas (containing <0.2ppm water) at 350℃ to remove water and oxygen and other impurities from the system.

[0038] Under high temperature conditions of 2.750℃, sulfur hexafluoride (containing <0.1ppm water) is introduced at a flow rate of 1.0L / min to decompose and generate fluorine gas and particulate ruthenium metal. The amount of sulfur hexafluoride introduced is twice that of ruthenium, and the reaction pressure is controlled at 0.2MPa.

[0039] S3. The generated fluorine gas reacts with ruthenium in the reactor to synthesize ruthenium hexafluoride. The pressure is 0.1 MPa, the temperature is 650℃, and the reaction time is 18 min to ensure a complete reaction without the formation of ruthenium fluoride in other valence states.

[0040] S4. Ruthenium hexafluoride is collected in a -10°C cryogenic collector. The collector is evacuated at low temperature to remove light component impurities from the gas and gas mixture. The light fluoride is recycled and reused. The pressure is controlled at -0.1 MPa. The purity of the received product ruthenium hexafluoride is 99.2%, and the yield is 90.5%.

[0041] Example 4

[0042] Examples of the synthesis of ruthenium hexafluoride according to the present invention are as follows:

[0043] S1. After adding irregular strip-shaped ruthenium metal with a purity of 96% to the Hastelloy reactor, the system is evacuated and replaced twice under nitrogen gas (containing water <0.2ppm) at 250℃ to remove water and oxygen and other impurities from the system.

[0044] Under high temperature conditions of 2.700℃, sulfur hexafluoride (containing <0.2ppm water) is introduced at a flow rate of 250m / min to decompose and generate fluorine gas and powdered ruthenium. The amount of sulfur hexafluoride introduced is 2.5 times that of ruthenium, and the reaction pressure is controlled at 0.05MPa.

[0045] S3. The generated fluorine gas reacts with ruthenium in the reactor to form ruthenium hexafluoride. The pressure is 0 MPa, the temperature is 600℃, and the reaction time is 25 min to ensure that the reaction is complete and no other valence state of ruthenium fluoride is generated.

[0046] S4. Ruthenium hexafluoride is collected in a -50°C cryogenic collector. The collector is evacuated at low temperature to remove impurities, and the light fluoride is recycled and reused. The pressure is controlled at 0 MPa. The purity of the collected ruthenium hexafluoride is 99.6%, and the yield is 89.3%.

[0047] Comparative Example 1

[0048] The difference from Example 1 is that the sulfur hexafluoride contains 10 ppm of water and the reaction time is 2 min, while the rest are the same.

[0049] The purity of the collected ruthenium hexafluoride product was 62.3%, and the yield was 56.5%.

[0050] Comparative Example 2

[0051] The difference from Example 1 is that sulfur hexafluoride is introduced under a high temperature of 280°C in S2, while the rest is the same.

[0052] The purity of the collected ruthenium hexafluoride product was 40.2%, and the yield was 36.6%.

[0053] Comparative Example 3

[0054] The difference from Example 3 is that the ratio of sulfur hexafluoride to ruthenium was 0.8:1, and all other conditions were the same. The ruthenium hexafluoride product collected had a purity of 35% and a yield of 40.8%.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for synthesizing highly safe ruthenium hexafluoride, characterized in that, The following steps are involved: S1. After adding ruthenium as the raw material to the reactor, the reactor is purged at 200-400°C with nitrogen or inert gas to remove water and oxygen impurities, and the water and oxygen content is controlled to be below 5 ppm. S2. Under high temperature conditions, sulfur hexafluoride is introduced and cracked to produce low-valent sulfur fluorides and fluorine gas; S3. The generated fluorine gas reacts with metallic ruthenium in a reactor at a pressure of 0–1.0 MPa and a temperature of 550–750 °C to generate ruthenium hexafluoride; S4. Collect ruthenium hexafluoride in a cryogenic collector at -70 to -10°C, remove impurities by low-temperature evacuation, and collect ruthenium hexafluoride products with a purity of >99%.

2. The method for synthesizing highly safe ruthenium hexafluoride according to claim 1, characterized in that, The moisture content of the inert gas used for S1 displacement and the sulfur hexafluoride gas used for the S2 reaction is <5 ppm.

3. The method for synthesizing highly safe ruthenium hexafluoride according to claim 1, characterized in that, The ruthenium used in S1 is in powder, granular, block, strip, or irregular shape, with a purity of ≥95%.

4. The method for synthesizing highly safe ruthenium hexafluoride according to claim 1, characterized in that, The high-temperature conditions for S2 are 550–750℃ and the pyrolysis reaction pressure is 0–0.2 MPa.

5. The method for synthesizing highly safe ruthenium hexafluoride according to claim 1, characterized in that, The ratio of sulfur hexafluoride to ruthenium introduced into S2 is 1 to 2.5:

1.

6. The method for synthesizing highly safe ruthenium hexafluoride according to claim 1, characterized in that, The reaction time for S3 is 5–25 min, and the flow rate is 250 mL–1.5 L / min.

7. The method for synthesizing highly safe ruthenium hexafluoride according to claim 1, characterized in that, The S4 collector removes impurities by low-temperature evacuation, with the pressure controlled between -0.1 and 0.1 MPa.

8. A method for synthesizing highly safe ruthenium hexafluoride according to claim 7, characterized in that, The S4 collector removes impurities at a temperature of -70 to -10°C through low-temperature evacuation.

9. A method for synthesizing highly safe ruthenium hexafluoride according to claim 1, characterized in that, The reactor is made of stainless steel, nickel, Monel alloy, and Hastelloy alloy.