Influence of atmospheric fluorine plasma treatment on thermal and dielectric properties of polyimide film

Plasma treatment of polyimide surfaces not only causes structural modification during the plasma exposure, but also leaves active sites on the surfaces that are subject to post-reaction. In this work, the effects of atmospheric fluorine plasma treatment on the surface properties and dielectric properties of polyimide thin film were investigated by using X-ray photoelectron spectroscopy (XPS), Fourier transform-IR (FT-IR) spectroscopy, and contact angle measurement. The results indicated that plasma treatment successfully introduced fluorine functional groups on the polyimide surfaces. The polyimides also exhibited good thermal stability and a lower dielectric constant. It appears that the replacement of fluorine led to the decrease of the local electronic polarizability of polyimide. Consequently, it was found that the atmospheric fluorine plasma-treated polyimides possessed lower dielectric characteristics than the untreated polyimides.

The dielectric constants ranged between 2.43–2.95 at 1 MHz and 25 °C, which was lower than those of the untreated polyimide film. It can be seen that the dielectric constant decreased with increasing fluorine content of the polyimide film when the temperature was kept constant.Figure optionsDownload as PowerPoint slide