Evaluation of Dust Particle Properties and Particulate Contamination in a PECVD Reactor by Visualization Measurements

Abstract

The properties and behavior of dust particles generated in the plasma reactor and their effects on film contamination are studied. The motion and spatial distribution of dust particles suspended in a PECVD reactor during fabrication of a SiO₂ thin film using tetraethylorthosilicate/oxygen/nitrogen plasma are visualized by using a laser light scattering technique. It is found that the particles are in many cases trapped at a certain region of plasma. The size of the dust particles and the structure of the particle clouds trapped are strongly dependent on the plasma operating conditions, and these also in turn influence the level of particulate contamination of the substrate. It was concluded that proper process conditions must be sought carefully to achieve films of good quality and sufficiently high growth rate with minimum particulate contamination.