Observation and evaluation of flaked particle behavior in magnetically enhanced reactive ion etching equipment using a dipole ring magnet

An in situ particle monitoring system using laser light scattering method was installed onto a commercially available radio frequency (rf) plasma oxide-etching tool that is enhanced magnetically using a dipole ring magnet. We observed the behavior of particles that flaked off the deposition film. It can be proven that the flaked particles have different trajectories depending on the magnetic field. When no magnetic field is applied, the flaked particles make a reciprocating motion near the grounded electrode due to the positive charge of flaked particles within the sheath. Alternatively, flaked particles enter the bulk plasma in response to a small gradient of electrical potential near the upper electrode when the magnetic field is active. Particles typically move horizontally with vertical vibration in bulk plasma using a magnetic field. The main force acting on the particles is electrostatic in nature.