Mechanism of high density plasma processes for ion-driven etching of materials

We propose a mechanism for ion-driven etching of materials in a high densit y plasma (>10(11) cm(-3)) system. An inductively coupled plasma (ICP) react or was used to model the etch mechanism. Ion density and plasma potential w ere measured with a Langmuir probe and the self-induced de bias simultaneou sly recorded. Power density (i.e, ion flux times ion energy) was found to b e the most influential factor for predicting the etch rate of ion-driven ma terials, like dielectrics and III-nitrides, especially when running in a hi gh density plasma (HDP) mode. Power density is also shown to be a function of ion mass, ion density, ion charge, de bias and plasma potential. The rel ation between these plasma parameters and power density can be correlated w ith process parameters such as TCP source power, rf chuck power, chamber pr essure and gas flow rate. This correlation was modeled with the aid of a de sign of experiment (DOE) simulation. We have demonstrated the use of a powe r density model to explain the mechanism responsible for HDP etching of SiO 2, which is one example of a high-bond strength material. (C) 1999 Elsevier Science Ltd. All rights reserved.