Molecular-dynamics simulations of organic polymer etching by hydrocarbon beams

Molecular-dynamics simulations of hydrocarbon beam injections into a poly (1,4-phenylene) substrate surface are carried out with the use of classical potential functions for covalent bonds of carbon and hydrogen atoms. Van der Waals interactions among carbon atoms are also taken into account. In the low injection energy (50eV) regime, we have observed that injected carbon atoms tend to be deposited on the surface, whereas hydrogen atoms tend to chemically break carbon bonds in the substrate. With the combination of chemical effects by hydrogen with large momenta carried by the injected carbon atoms, hydrogen-rich carbon clusters can etch organic polymer surfaces with relatively high efficiency. Implications of our simulation results on etching processes of low-dielectric-constant organic polymers by hydrogen-nitrogen plasmas are also discussed.