ETCH-INDUCED DAMAGE IN HIGH-DENSITY INDUCTIVELY-COUPLED PLASMA-ETCHING REACTORS

A fundamental understanding of damage to thin oxides in inductively co upled plasma (ICP) etching reactors is required to enable their widesp read acceptance. XPS, C-V, DLTS and electrical breakdown techniques we re used to study damage in a ICP reactor configuration capable of gene rating very uniform plasma. A Langmuir probe was employed to study the uniformity but any micro-nonuniformity close to the wafer surface cou ld not be clearly identified. Etch induced electrical damage to thin o xide was found to be in good agreement with physical damage. It was ob served that the degradation to thin oxide is associated with the high- energy electron bombardment when only the rf coil is powered with a fl oating 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.