Adsorption isobars of fluorocarbon compounds selected for cryogenic plasma etching of low-k dielectrics
In this paper we describe a method for determination the necessary parameters of various chemicals,used for cryogenic etching, using the Antoine's equation, the equations for calculating the temperature dependence of the density and the surface tension. In developed method we are recalculated adsorption isotherm of toluene at room temperature to adsorption isobar of hexafluorobenzene (C6F6) and perfluorocyclobutane (C4F8) at low temperatures, that are selected as chemical compounds which condense into the pore of low-k dielectric before cryogenic etching. Comparisons were made between the calculated and experimental isobars. We explained the differences in the obtained results, the causes of the hysteresis in the experimental adsorption / desorption isobar of C6F6 and C4F8.