Particle growth in plasmas

Abstract

Plasmas are used extensively in the manufacturing of microelectronic devices. In typical fabrication facilities, plasmas may be used for etching, deposition, cleaning of a substrate, and chamber cleaning. One of the major challenges to the effective use of plasmas for microelectronics processing is the formation of particles and films from reaction byproducts, which can contaminate both the substrate and the chamber. However, in other communities, the growth of particles and films in plasmas provides opportunities for the production of novel materials, for studies of astrophysical phenomena, and for macroscopic simulations of condensed matter physics. Extensive studies of particles and films in plasmas have resulted in an understanding of particle dynamics including charging, trapping, transport, and deposition. However, comparatively little is understood about the nucleation and growth behavior of particles and films. In this contribution, particle and film formation mechanisms in low-pressure fluorocarbon plasmas are discussed. It is shown that gas phase molecular growth reactions are responsible for the formation of chemical precursor to particle and film nucleation. A fluorocarbon chemical reaction library has been developed, and when used in conjunction with a plasma chemical kinetics model, gives excellent agreement with experimental observations of molecular growth reactions and particle and film formation.