Permanent-magnet helicon sources and arrays: A new type of rf plasma

摘要

Helicon discharges are known for their ability to produce high densities of partially ionized plasma,their efficiency arising from an unusual mechanism of rf coupling. However, the requirement of adc magnetic field has prevented their wide acceptance in industry. The use of permanent magnetsgreatly simplifies helicon sources, and arrays of small sources extend the use of helicons to theprocessing of large substrates. An eight-tube array was designed and constructed, and its densityuniformity measured in a 53 X 165 cm~2chamber. Three innovations involved (a) the remote field ofring magnets, (b) a low-field density peak, and (c) rf power distribution. High-density plasmasuniform over large areas requires compatibility in all three areas.