The charge build-up in an electron cyclotron resonance (ECR) etcher has been studied experimentally and theoretically. The experimental results show that the charge build-up profiles of the wafer are convex and positive, and are detected only when the RF bias exists. We have derived a simplified equivalent circuit model for the wafer in an ECR etcher. The charge build-up profile predicted with the simplified equivalent circuit model shows a good agreement with the experimental results. It is concluded that the variation of plasma potential caused by the radial RF current across the magnetic field results in the charge build-up.

The charge buildup in a magnetron etcher has been studied experimentally for two different magnet arrangements and theoretically on the basis of an equivalent circuit model. Wafer charging measured with a metal-Si3N4-SiO2-Si (MNOS) capacitor is negative along the centerline of the magnet poles and positive between the magnets in both cases. Wafer charging is explained either by curtent crowding at the center of the magnet poles or by the nonambipolar diffusion effect.