CF4 plasma etching of materials used in microelectronics manufacturing

Amorphous hydrogenated carbon a-C:H films, deposited on silicon substrates by radio frequency plasma-enhanced chemical vapor deposition (RF PECVD), and AZ(R) 5214 organic photoresist have been etched in a low-pressure and high frequency tetrafluoromethane (CF4) plasma. The etching of Si and SiO2 was also measured in order to determine their selectivities to a-C:H films and AZ 5214 photoresist. The etch rates were measured as a function of RF power in the range of 20-60 W. Carbon a-C:H films were found to be more etch resistant than organic AZ 5214, Si, and SiO2. AZ 5214 demonstrated a relatively high etch rate (300-700 Angstrom/min). The best etch rate ratios of Si and SiO2 to carbon films were achieved at low RF power. Carbon films can be used as masks for deep pattern transfer to Si and SiO2 in photolithography. (C) 2000 Elsevier Science Ltd. All rights reserved.