Patent ID: 7165506

Claim:
A device for reducing a thickness of a substrate by ion etching; the device comprising: a vacuum chamber ( 1 ); an etching gas supply for supplying an etching gas to the vacuum chamber; a first electrode and a second electrode; wherein the first electrode ( 5 ) has a shape of a ring; wherein the second electrode ( 4 ) is arranged approximately on a center axis of the ring of the first electrode ( 4 ); wherein a substrate is arranged symmetrically on the center axis of the ring of the first electrode; wherein the first and second electrodes, viewed in an axial direction of the center axis of the ring of the first electrode, are arranged between the etching gas supply and the substrate; wherein the first and second electrodes are configured to be supplied with a direct voltage or alternating voltage for producing a plasma of the etching gas by an electric arc that is locally separated from the substrate; wherein ions of the etching gas are accelerated by an electric potential supplied to the substrate such onto the substrate that a surface of the substrate is etched and a thickness of the substrate is reduced; magnetic coils ( 8 ) correlated with the vacuum chamber ( 1 ) and arranged in a ring shape; activation means activating the magnetic coils to create a rotating magnetic field such that the electric arc, produced between the first and second electrodes and locally separated from the substrate, circulates along the first ring-shaped electrode in a carousel fashion.