ROLES OF IONS AND NEUTRAL ACTIVE SPECIES IN MICROWAVE PLASMA-ETCHING

The roles of ions and neutral active species in microwave plasma etching are investigated. Silicon wafers are etched in a (CF4 + O2) mixture discharge. The results of three different experiments agree and are suggestive of the following: Si wafers can be etched only when ions impinge on the wafer surface at pressures lower than 0.13 Pa (1 × 10-3 Torr), Si wafers are etched by neutral active species at pressures higher than 1.3 Pa (1 × 10-2 Torr), and both by ions and neutral active species at pressures between 0.13 Pa (1 × 10-3 Torr) and 1.3 Pa (1 × 10-2 Torr). © 1979, The Electrochemical Society, Inc. All rights reserved.