Plasma etching is an indispensable technique for patterning
thin films in the fabrication of very-large-scale integrated
~VLSI! circuit devices. As the manufacture of VLSI moves
towards less than the subquarter micron design rule, the requirements
for etching are increasingly difficult to meet using
conventional rf plasma sources. Alternative to these
plasma sources are low-pressure, high-density plasma
sources, e.g., electron cyclotron resonance ~ECR! plasma,
inductively/transformer coupled plasma ~ICP/TCP!, helical
resonators and helicon plasma sources. Such plasma sources
can generate higher density plasma with a lower operating
gas pressure and a lower sheath voltage, compared to conventional
rf plasma, and are expected to achieve a betteretched
profile with higher selectivity.