Abstract
Oxygen mixed with nitrogen trifluoride (NF3) was used for the gas source of the plasma etching as one of the methods to improve the etch rate of the polyimide (PI) film. In order to investigate the effects of NF3 addition, the surfaces of the PI film were analyzed with x-ray photoelectron spectroscopy (XPS), optical profilometer and Fourier transformation infrared spectrometer (FT-IR). From the results of surface analyses with XPS, the chemical bonding state of the etched PI surface with the 30% NF3/70% O2 plasma was similar to that of the 100% O2 plasma rather than the 80% NF3/20% O2 plasma. Peak intensities of the benzene ring and imide moietiy were decreased, but that of C-OH and carboxyl moiety were increased as etching time was increased. From the observations of surface analyses with optical profilometer, the roughness of the etched PI surface with the 30% NF3/70% O2 plasma was smother than the 100% O2 plasma. From the results of FT-IR, the part of deposition material, which was soluble in chloroform, on the etched PI film was estimated to be carbonyl and ether compounds.
