Capacitively coupled plasma, CCP

RIE equipment is usually parallel plate reactors in which both plasma and DC bias voltage are created using one capacitively coupled plasma (CCP) source [5]. The wafers are placed on top of the electrode which is typically in direct contact with plasma glow (Fig. 3). This ensures a reasonable etch rate but the controllability of etching is difficult. A major downside of this type of reactor is that the wafers are exposed to heavy ion bombardment because plasma generation and bias voltage are coupled. The etch rate of silicon is typically 0.1 - 1 (xm/min and selectivity against the photoresist mask is usually below 5 1. Anisotropy is based on the directionality of ion bombardment and aspect ratios are usually limited to 2 1. 

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