Properties of boron carbon nitride (BCN) film after plasma ashing

Dry etching and resist ashing of a low dielectric constant interlayer (low-k) are required for the formation of a trench structure, which is necessary for the fabrication of damascene interconnections using materials such as Cu. We investigated the properties of boron carbon nitride (BCN) film after plasma ashing by H2/N2 gas and O2 gas and compared with porous SiOC (P-SiOC) thin film. It is found that by ashing with O2 or N2/H2 plasma, BCN film composition does not change and the film damage is also little in the view points of leakage currents and dielectric constant. Hence, it is understood that both N2/H2 or O2 gas plasma can be used for interconnection process of with BCN low-k film.