Particle (de-)charging in low pressure afterglow plasma for contamination control: a comparative study between conducting and non-conducting particles

In modern semiconductor processing, maintaining ultralow levels of contamination by (sub)micrometer-sized particles is crucial. Such contaminants may be introduced into these environments from the outside through translational and/or rotational (robotic) feedthroughs. A promising way forward to mitigate particle contamination is by developing plasma-enhanced contamination control strategies, particularly plasma-enabled vacuum seals for these feedthroughs. To drive the development of this technology, our ongoing research focuses on unraveling elementary processes governing free-floating particles, immersed in a low-pressure gas flow, that interact with plasma and externally applied electric fields. The plasma seal concept involves using plasma to electrically charge the contaminants and subsequently allowing electric fields to control the particles’ trajectories and deflect them to areas where they can be removed, or which are less susceptible to contamination. In this contribution, we present new experimental results demonstrating distinct differences in plasma-induced particle (de-)charging between conducting and non-conducting particles.