Inductively coupled plasma reactive ion etching (ICP-RIE) of copper thin films patterned with SiO2 hard masks was carried out using piperidine/O2/Ar gas mixture. The etch rate, etch selectivity, and etch profile of copper thin films were investigated by varying gas concentration in piperidine/O2/Ar gas mixture. In addition, the etch parameters including ICP RF power, DC-bias voltage to substrate, and process pressure were varied to examine the etch characteristics. X-ray photoelectron spectroscopy and optical emission spectroscopy were employed to elucidate the etch mechanism under piperidine/O2/Ar gas chemistry. Finally, 150 nm-line patterned copper thin films were successfully etched using piperidine/ O2/Ar etch gas under the optimized etch conditions.
