Dynamic laser light scattering studies of dusty plasmas in the Gaseous Electronics Conference Reference Cell

Particle generation has been studied during reactive ion etching of oxide wafers in CF4/CHF3 plasmas using the Gaseous Electronics Conference Reference Cell. Under certain discharge process conditions, copious amounts of submicron particles form due to plasma interactions with the oxide substrate. Particles were observed in situ by laser light scattering and dynamic laser light scattering (DLLS). DLLS can be used to determine information about particle size, motion, and growth dynamics. DLSS measurements show process-induced dust particles confined in an electrostatic trap exhibit low-frequency oscillatory motion consistent with charge-density-wave motion. These results are also consistent with the plasma dust particles forming a strongly coupled Coulomb liquid phase. (C) 1996 American Vacuum Society.