Handbook of Silicon Based MEMS Materials and Technologies

23.2. Equipment

Parallel plate reactors in which both plasma and DC bias voltage are created using one capacitively coupled plasma (CCP) source are prototypical RIE reactors. The wafer is placed on top of the RF driven electrode (commonly 13.56 MHz) which is typically in direct contact with plasma glow. This ensures a reasonable etch rate but makes the controllability of etching difficult. Plasma is generated from selected etch gases. Because the electrons have high mobility compared to ions, the electrode charges negatively in RF driven plasmas [6]. This DC bias voltage between the plasma and the electrode generates ion bombardment towards the electrode. In order to achieve adequate plasma density quite high RF powers are used. Because the ...