A method of etching a layer including at least one pattern that has flanks is provided, including at least one step of modifying the layer by putting the layer in presence with a plasma into which CxHy is introduced and which includes ions heavier than hydrogen; and wherein the plasma creates a bombardment of ions with a hydrogen base coming from the CxHy, the bombardment being anisotropic according to a main direction of implantation parallel to the flanks and so as to modify portions of the layer that are inclined with respect to the main direction and so as to retain unmodified portions on the flanks, wherein chemical species of the plasma form a carbon film on the flanks; and at least one step of removing the modified layer to be etched using a selective etching of modified portions of the layer with respect to the carbon film.