Phenomenological study of particulates in plasma tools and processes

Particle contamination in a variety of plasma processes and tools has been studied using a real-time, in situ detection technique, rastered laser light scattering. In agreement with previous studies, particles were suspended in the plasma. The distribution of particles, however, is highly ordered and predictable, in contrast to the randomness which typifies particulate behavior in uncharged environments such as cleanrooms. The importance of electrostatic particle trapping is seen as a means of understanding this ordered distribution of particles, for predictive performance of process tools in manufacturing, and for contamination control in processing tools. The implications of these results on future plasma processing is briefly discussed.