An electron cyclotron resonance plasma is produced with a multislot an
tenna, where r.f. powers (13.56 MHz) are applied to a substrate. Plasm
a parameters measured with a probe are examined as a function of r.f.
power and pressure. It is found that when the r.f. powers are applied,
negative self-bias potential appears and the plasma density tends to
decrease and the plasma potential increases. Furthermore, the effect o
f the negative self-bias potential on the radial profile of plasma par
ameters is discussed.