Interface formation and adhesion of metals (Cu, Ta, and Ti) and low dielectric constant polymer-like organic thin films deposited by plasma-enhanced chemical vapor deposition using para-xylene precursor

The interface formation, adhesion and diffusion properties of metals (Cu, Ta, and Ti) and low dielectric constant (low k) polymer-like organic thin films (POTFs) deposited by plasma-enhanced chemical vapor deposition (PE-CVD) using the para-xylene precursor were investigated. Cu, Ta and Ti deposited on the surfaces of POTFs treated by O₂ and N₂ plasmas generated in a magnetically-enhanced inductively coupled plasma (ME-ICP) reactor. X-ray photoelectron spectroscopy (XPS) was used to study the chemical interactions between metals and POTFs. As a result of formation of new binding states by plasma treatment, the adhesion strength of metals and POTFs was increased. Diffusion properties of metals into POTFs were investigated using Rutherford backscattering spectroscopy (RBS) for the vacuum-annealed Cu/POTFs and Ta/POTFs for 1 h at 450 °C. Also, from the RBS spectra, it was observed that Cu and Ta in the post-annealed samples were not diffused into both POTFs with and without plasma surface treatments.