A unified global self-consistent model of a capacitively and inductively coupled plasma etching system

Abstract

Based on the concept of independent control of ion flux and ion-bombardment energy, a global selfconsistent model was proposed for etching in a high-density plasma reactor. This model takes account of the effect on the plasma behavior of separate rf chuck power in an Inductively Coupled Plasma etching system. Model predictions showed that the chuck power controls the ion bombardment energy but also slightly increases the ion density entering the sheath layer, resulting in an increase in etch rate (or etch yield) with increasing this rf chuck power. The contribution of the capacitive discharge to total ion flux in the ICP etching process is less than about 6% at rf chuck powers lower than 250 W. As a model system, etching of InN was investigated. The etch yield increased monotonically with increasing the rf chuck power, and was substantially affected by the ICP source power and pressure. The ion flux increased monotonically with increasing the source power, while the dc-bias voltage showed the reverse trend.