99.999% (5N) High Purity Carbon Tetrafluoride

Product Category: Carbon Tetrafluoride
Purity: 99.999% (5N)
Packaging: Seamless Steel Cylinder
CAS: 75-73-0
EINECS: 200-896-5
Molecular Formula: CF4

Related Parameters of High-Purity Carbon Tetrafluoride

Product Grade: Analytical Reagent
Product Purity: 99.999%
Packaging Specification: 40L
English Name: Carbon Tetrafluoride
English Alias: Tetrafluoromethane
CAS: 75-73-0
EINECS: 200-896-5
Molecular Formula: CF4
Molecular Weight: 88
Physical and Chemical Properties: - Melting Point: -184°C

Filling Standards for High-Purity Carbon Tetrafluoride

Applications of Carbon Tetrafluoride

Carbon tetrafluoride is currently the most widely used plasma etching gas in the microelectronics industry, including high-purity carbon tetrafluoride and its mixtures with high-purity oxygen.
1. It is widely used for etching silicon, silicon dioxide, silicon nitride, phosphosilicate glass, and tungsten thin-film materials. For silicon and silicon dioxide systems, using CF4-H2 reactive ion etching allows for a selectivity of 45:1 by adjusting the gas ratio, which is particularly useful for etching silicon dioxide films on polysilicon gates.
2. It is also extensively used in surface cleaning of electronic devices, solar cell production, laser technology, gas-phase insulation, low-temperature refrigeration, leak detection agents, space attitude control, and decontaminants in printed circuit board production.
3. Due to its high chemical stability, CF4 is also used in metal smelting and the plastics industry.
4. Carbon tetrafluoride has excellent oxygen solubility, making it suitable for ultra-deep diving experiments as a replacement for ordinary compressed air. Successful experiments on mice have shown safe recovery at depths between 275 meters and 366 meters.

Synthesis Methods of Carbon Tetrafluoride

1. Carbon tetrafluoride can be produced by reacting carbon with fluorine, carbon monoxide with fluorine, silicon carbide with fluorine, fluorite with petroleum coke in an electric furnace, dichlorodifluoromethane with hydrogen fluoride, carbon tetrachloride with silver fluoride, or carbon tetrachloride with hydrogen fluoride. The reaction of carbon tetrachloride with hydrogen fluoride takes place in a high-temperature nickel tube filled with chromium hydroxide. The resulting gas is washed with water and alkali to remove acidic gases, then dehydrated by freezing and silica gel, and finally purified by distillation.
2. Pre-weigh 5–10g of silicon carbide powder and 0.1g of elemental silicon powder, place them in a nickel tray to ensure full contact, and then put the tray into a Monel alloy reaction tube. Introduce fluorine gas, which first reacts with elemental silicon, generating heat. Fluorine then reacts with silicon carbide. Dry nitrogen is introduced at an equal volume to dilute the fluorine and sustain the reaction. The generated gas is condensed in a nickel trap cooled by liquid nitrogen, slowly vaporized, passed through a scrubber containing sodium hydroxide solution to remove silicon tetrafluoride, and then dried through silica gel and phosphorus pentoxide towers to obtain the final product.
3. It is prepared by fluorination reaction using activated carbon and fluorine as raw materials. In a reaction furnace containing activated carbon, high-concentration fluorine gas is slowly introduced, and the reaction temperature is controlled by a heater, fluorine supply rate, and furnace cooling. The product is dedusted, washed with alkali to remove impurities such as HF, CoF2, SiF4, and CO2, and then dehydrated to obtain a crude product with about 85% purity. The crude product is introduced into a low-temperature distillation still for batch distillation. By controlling the distillation temperature, O2, N2, and H2 are removed to obtain high-purity CF4.

Storage Precautions for Carbon Tetrafluoride

1. The use and inspection of gas cylinders must comply with the "Gas Cylinder Safety Supervision Regulations" issued by the State Administration of Quality and Technical Supervision.
2. Cylinders must not be placed near fire sources, exposed to direct sunlight, and should generally be kept at least 10 meters away from open flames. Cylinders must not be subjected to impact.
3. Cylinders must never be contaminated with oil or grease.
4. The gas in the cylinder should not be completely used up; a residual pressure of no less than 0.04 MPa must remain.