Monitoring particle growth in deposition plasmas

Plasma-enhanced chemical vapor deposition methods are frequently used to deposit barrier layers, e.g. on polymers for food packaging. These plasmas may suffer from particle (dust) formation. We report on a flexible monitoring system for dust. It is based on scanning a 3D plasma volume for particles by laser light scattering. The lower size limit of particles detected in the presented system is 20 nm. We report on existence diagrams for obtaining dust free or dust loaded capacitively or inductively coupled rf-plasmas in C 2 H 2 depending on pressure, flow and rf-power. We further present growth rates for dust in these plasmas and show that monodisperse particles are only obtained during the first growth cycle.