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Introduction and Applications of Ethylene Fluoride

2022-05-20 09:08

Hexafluoroethane, chemical name 1,1,1,2,2,2-hexafluoroethane, also known as R116, FC-116, PFC-116, Halocarbon 116, English name 1,1,1,2,2,2-Hexafluoroethane, CAS No. 76-l6-4, is a colorless, odorless, non-flammable, non-toxic gas, more easily liquefied, highly stable. Highly stable. It is essentially insoluble in water, soluble in hydrocarbons such as butane, benzene, toluene, chlorinated solvents such as carbon tetrachloride and lubricants for the refrigeration industry, as well as in alcohols, ketones, lipids and some organic acids, insoluble in n-glycol, glycerol, phenols and castor oil. High purity HFO is a fluorocarbon gas, mainly used for plasma etching in the production of integrated circuits, as well as for surface cleaning of devices. As the IC process gradually enters 28mm, 14nm and even 7mm, the high precision requirements dictate the use of high purity HFO gases with high etch rates and high accuracy, making it a promising application.

Due to its non-toxicity, odourlessness and high stability, HFO is widely used in semiconductor manufacturing processes, for example as an etchant (Dry Etch) and as a cleaning chamber after Chemical Vapor Deposition (CVD). Especially with the development of semiconductor devices, integrated circuits are becoming more and more precise, and conventional wet etching cannot meet the requirements of 0.18~0.25um deep submicron integrated circuits with high precision fine line etching. Hexafluoroethane as a dry etchant has the advantages of minimal lateral edge erosion, high etch rate and high accuracy, which can meet the requirements of such processes with small line widths extremely well. In particular, the original octafluorocyclobutane is unable to etch when in contact with components with apertures of 140 nm or less, whereas hexafluoroethane can produce a deep groove on components as small as 110 nm. In the area of clean gases for CVD chambers, HFC-134 and HFC-134 are traditionally used, while HFC-138 and NF3 have also been introduced to meet the latest process specifications and production efficiencies.

For all CVD processes based on SiH4, HFO is superior to HFC4 as a cleaning gas, mainly in terms of low emissions, high gas utilisation, reflective choke cleanliness and high plant throughput.

The most common process used at home and abroad for the preparation of high purity HFO is the HFO purification process, where industrial HFO is used to obtain high purity HFO by purification. When using industrial HFO purification method to prepare high purity HFO, the type and content of impurities contained in industrial HFO vary due to the different preparation process routes of HFO. Most of the HCFC by-products such as trifluoromonochloromethane, difluorodichloromethane and trichloromonochloromethane can be removed by adsorption distillation, but some impurities are stable or can form azeotropes with HFO, which cannot be removed by adsorption distillation. The high purity HFO used in the microelectronics industry must be purified to a concentration below that specified.

The molecular structure of HFC-116 is very stable and its high energy C-F bonding makes it difficult to decompose, its life cycle in the atmosphere is up to 10,000 years and this effect is cumulative and irreversible. PFC emissions from semiconductors account for approximately 0.11% of the global greenhouse gas emissions, which has led the electronics industry to investigate process improvements and reduction actions to reduce PFC emissions. The second stage is the development of environmentally friendly alternatives to PFC that fully meet the requirements of use. R116 is used in the etching and cavity cleaning processes of wafer manufacturing.