Study on the plasma-polymer thin films deposited by using PECVD and application tests for low-k insulator

Plasma-polymer pure ethylcyclohexane thin films were deposited on Si(100) substrates at room temperature by using PECVD (plasma enhanced chemical vapor deposition). Hydrogen and argon gases were used as precursor bubbler and carrier gases, respectively. We also investigated the electrical and the physical properties of the plasma-polymer thin films at various deposition RF powers and annealing temperatures. The as-grown and the annealed plasma-polymer thin films were analyzed by using FT-IR, (Fourier transform infrared spectroscopy) and SEM (scanning electron microscopy). The IR, spectra showed that the plasma-polymer thin films had totally different chemical functionalities from those of the ethylcyclohexane precursor and that the chemical functionalities of the thin films changed with the BF power and annealing temperature. From the SEM results, we determined the thicknesses of the thin films before and after the annealing, with the thickness shrinkage (%) being measured by using SEM cross-sectional images. An impedance analyzer was used to measure the capacitance and from the electrical property measurements, the lowest dielectric constant obtained was 1.71.