Investigation of the gas pressure influence on patterned platinum etching characteristics using a high-density plasma

Abstract

A high-density surface-wave magnetized argon plasma operated in the very low pressure regime together with a rf biased system is used to study the pure physical etching characteristics of platinum thin films. It is shown that, for a given dc self-bias voltage, the platinum etch rate strongly decreases as the operating pressure increases, which results from a decrease of the ion density at the sheath edge and from enhanced redeposition. It is found that using a high-density plasma in the very low pressure regime yields high etch rates with a good selectivity over resist. Fence-free features can also be achieved at bias voltages that, in contrast with reactive ion etching reactors, are only slightly above the platinum sputtering threshold. © 2001 American Institute of Physics.