A device and method for polishing the surface of a substrate uses a vessel for holding a plasma in a magnetic field. Further, the magnetic field is selectively oriented in the vessel relative to the substrate surface. An ion accelerator is then activated to accelerate ions from the plasma on a curved path toward the substrate. By controlling the strength of the magnetic field, and the r-f power and frequency needed to accelerate the ions, the accelerated ions are sent on the curved path for collision with the substrate surface. These collisions, which occur at grazing angles in the range of 0.degree.-20.degree., remove atoms from the substrate surface and thereby polish the surface.