Etching characteristics of photoresist and low-k dielectrics by Ar/O2 ferrite-core inductively coupled plasmas

We have investigated the characteristics of Ar/O"2 plasmas in terms of the photoresist (PR) and low-k material etching using a ferrite-core inductively coupled plasma (ICP) etcher. We found that the O"2/(O"2+Ar) gas flow ratio significantly affected the PR etching rate and the PR to low-k material etch selectivity. Fourier transform infrared spectroscopy (FTIR) and HF dipping test indicated that the etching damage to the low-k material decreased with decreasing O"2/(O"2+Ar) gas flow ratio.