PARTICLE TRAPPING, TRANSPORT, AND CHARGE IN CAPACITIVELY AND INDUCTIVELY-COUPLED ARGON PLASMAS IN A GASEOUS-ELECTRONICS-CONFERENCE-REFERENCE-CELL

Particle trapping has been observed for both a capacitively coupled an d an inductively coupled Gaseous Electronics Conference Reference Cell . Particles in the system were formed by introducing 10% CCl2F2 into a n argon discharge for 5-10 min and sputtering the resulting film durin g argon-only experiments. The particles generated were 200-600 nm in d iameter. Particle transport was observed in the postplasma regime for both capacitively and inductively coupled cases. For the capacitively coupled plasma, particles of positive, negative and neutral charge wer e found during the postplasma and shown to be affected by the presence of a de field during the postplasma period. The charge on these parti cles was determined to be between 1.4 and 12.4 electron charges based on a study of particle motion. This compares to a theoretical value of 800-2600 while the plasma is ignited. For the inductively coupled pla sma both a low density mode and a high density mode were observed, bei ng distinguished by a sudden increase in the emission from the plasma as rf power to the inductive coil was increased. In the high density m ode of the inductively coupled plasma, the particle cloud was observed to reside less than a millimeter from the powered electrode as the hi gh density plasma mode was established. This was distinguished from a trap height of 4-7 mm for the capacitively coupled plasma which corres ponds to the sheath thickness. (C) 1996 American Vacuum Society.