INVESTIGATION OF MULTIPOLAR ELECTRON-CYCLOTRON-RESONANCE PLASMA SOURCE SENSORS AND MODELS FOR PLASMA CONTROL

The sensors and models needed for the control of a high-density, multi polar, electron cyclotron resonance (ECR) plasma source have been stud ied for an argon soft-sputter clean process for semiconductor wafers. The ECR plasma source studied had a discharge diameter of 12.5 cm, a p rocessing chamber diameter of 40 cm, and an excitation frequency of 2. 45 GHz. The implementation of control on this plasma machine has been investigated by characterizing the machine using plasma diagnostic mea surements, by implementing and testing sensors, and by developing both analytical and statistical models of the machine operation. The real- time usage of sensor data together with input parameter adjustments ha s been used to obtain predictable soft-sputter/etch rates in the proce ss. (C) 1996 American Vacuum Society.