Tetrafluormethane CF4 corresponds to the methane molecule in which all 4 hydrogen bonds are replaced by fluorine.
In plasma processes , this is a frequently used process gas, particularly for etching. Tetrafluormethane (CF4, also referred to as Freon 14) is completely inert under normal conditions. In the plasma, however, it forms free fluorine atoms and CF2 and CF3 radicals. These have a very significant etching effect, e.g. on silicon dioxide. Mixtures of CF4 and O2 etch approximately 5 times faster than pure oxygen.