This paper addresses plasma etch properties as they relate to polymer type and etch gas composition. Polyacrylate,polyester, and polymers containing nitrogen and halogens have been investigated. The research was carried out by aseries of designs of experiments (DOEs), which varied the flow rate of Ar, CF4, and O2 in plasma gas. The selectivity ofBARC to resist depends not only on the carbon content but also on the different ways polymer compositions andstructures respond to an oxidizing gas, a reducing gas, and plasma bombardment. Based on a polymer decompositionmechanism, we discuss what could happen physically and chemically during the polymer’s exposure to the high-energyreactive plasmas. We also modified the Ohnishi parameter for the polymers containing nitrogen and halogen using ourpolymer decomposition theory. The contribution of nitrogen and halogen in the etch equation can be positive ornegative depending on the chemical properties of the plasma.