Enhanced Chemisorption of Cu(hfac)$_{2}$ on Parylene Surface by N$_{2}$ Plasma Treatment

The metallization of polymers has been intensively studied due to its wide industrial applications. We report a study of interfacial interaction of metalorganic Cu(hfac)$_{2}$ with the Parylene surface. Parylene is a low k dielectric polymer prepared by a chemical vapor deposition technique. The as-deposited Parylene surface is shown to be hydrophobic with a measured water droplet contact angle $\sim $72\r{ }. However, after the N$_{2}$ plasma treatment, the water droplet contact angle decreases to $\sim $40\r{ } due to the formation of oxygen and nitrogen functional groups on the surface, as observed by x-ray photoelectron spectroscopy (XPS). These functional groups improve Cu(hfac)$_{2}$ chemisorption on the plasma treated Parylene surface. Further studies by XPS show that chemisorption of Cu(hfac)$_{2}$ is self-limiting up to 20 sec of Cu(hfac)$_{2}$ precursor exposure time. The enhancement of chemisorption of metalorganic precursors on the polymer surface is an important step for chemical vapor deposition or atomic layer deposition of metal. $^{a }$Supported by Thai govt. fellowship (SP) and SRC (JSJ).