Patent ID: 7285228

Claim:
A method for anisotropically etching a substrate, the method comprising: generating a high-frequency electromagnetic alternating field with a plasma source, which generates a plasma having reactive species, within a chamber, in a reaction region, by an action of the alternating field on an etching gas introduced into the reaction region and a passivation gas introduced into the reaction region; in the reaction region, introducing the etching gas at least predominantly into a plurality of first zones, and introducing the passivation gas at least predominantly into a plurality of second zones, the etching gas zones and the passivation gas zones alternating around a circumference in the overhead view, wherein reactive etching gas species are generated in the first zones by a plasma generated there, and reactive passivation gas species are generated in the second zones by a plasma generated there; and blending the etching gas species and the passivation gas species with one another in a mixing region downstream of the reaction region before they act on the substrate.