Polymerization processes in a chloro-p-xylene discharge.

摘要

The following work is aimed to understand the effect of plasma chemistry on the film growth of plasma chemical vapor deposited Parylene C. Our data suggests that the film growth/polymerization of plasma deposited Parylene C is a process where both the adsorption of the monomer in the surface and the generation of precursors for polymerization by the plasma are very important. Ions are very likely to be the main precursors promoting polymerization of the films, but we cannot discard some small radical contribution. We used Fourier transform infrared spectroscopy, optical emission spectroscopy (OES) and an electron beam OES diagnostic tools to study the dissociation, excitation and ionization fragments produced in the plasma discharge. The main products of the monomer breakup are HCl, CH4, C2H2, H, H2, Cl, Cl2, CH, HCl+ and a mix of aromatic ions/radicals. By using a novel OES e-beam diagnostic we could track real time changes in the OES intensities of the excited species being produced and consumed in the plasma. Benzyl ions are likely to be produced by primary processes while the ion radicals by secondary/tertiary processes. Film deposition occurred mostly in areas exposed to ion bombardment. We characterized the plasma parylene C films and compare their properties with those of the conventional chemical vapor deposition (CVD) parylene C. Plasma parylene C properties are close to those of the films produced with the CVD method. We are reporting the first example of a plasma polymer that presents a degree of crystallinity.