Analysis of the negative ion characteristics of O-2 supermagnetron plasma for submicron etching use

In supermagnetron plasma generations using the electronegative gas O-2 and the electropositive gas Ar, electrical properties such as self-bias voltage and rf voltage for both gases were measured. In the measurement of self-bi as voltage, that of O-2 was about + 15 V higher than that of Ar; however, r f voltages for both O-2 and Ar were almost the same. From these experiments , the existence of negative ions in O-2 supermagnetron plasma was confirmed . Furthermore, the mechanism of the self-bias voltage shift in a positive d irection was analyzed by estimating their plasma and sheath potential diffe rences. Using this O-2 supermagnetron plasma, quartermicron resist patterns were etched with negligible side-wall etching. (C) 1999 Elsevier Science L td. All rights reserved.