Advanced Plasma Processing Equipment without Wafer Surface Damage and Chamber Material Contamination

The effects of magnetic field, excitation frequency, D.C. biases, secondary RF excitation, chamber material and the auxiliary electrode on spatial distribution of potential and self-biases are discussed and illustrated. The plasma potential strongly alters the ion impact energy in the regime of extremely low energy under high RF excitation in a very low pressure environment. The study found the plasma potential, the primary cause of chamber material contamination, can be lowered to sub-ground level by introducing an auxiliary shielding electrode.