Etch-induced damage in high-density inductively coupled plasma etching reactors

A fundamental understanding of damage to thin oxides in inductively coupled plasma (ICP) etching reactors is required to enable their widespread acceptance. XPS, C-V, DLTS and electrical breakdown techniques were used to study damage in a ICP reactor configuration capable of generating very uniform plasma. A Langmuir probe was employed to study the uniformity but any micro-nonuniformity close to the wafer surface could not be clearly identified. Etch induced electrical damage to thin oxide was found to be in good agreement with physical damage. It was observed that the degradation to thin oxide is associated with the high-energy electron bombardment when only the rf coil is powered with a floating rf electrode that holds the wafer. However, when both the coil and the electrode are powered the intensity of damage is a function of rf power.