A method for producing electrically conductive lines on a planar substrate, embedded in a dielectric material, wherein at least two colinear lines (23a,23b) are separated by a dielectric gap between the tips of said two lines, the method comprising the following steps: - producing a mask layer on a layer of said dielectric material formed on the substrate, - producing an intermediate layer on top of and in contact with the mask layer, - producing a sacrificial structure on the intermediate layer, the sacrificial structure comprising at least two parallel and mutually facing sidewalls of the structure with an elongate open area between said sidewalls, the open area extending in the X-direction of an orthogonal X-Y axis system in a plane parallel to the substrate, - by a lithography and etch process, producing an essentially rectangular opening in the intermediate layer, thereby locally exposing the mask layer, wherein ∘ the size of the opening in the Y-direction is self-aligned relative to the two parallel sidewalls, ∘ the size of the opening in the X-direction is defined by a mask pattern applied in the lithography and etch process, - depositing a layer of spacer material conformally on the sacrificial structure and on the bottom and sidewalls of the opening, - etching back the spacer material so as to expose the top of the sacrificial structure, thereby creating: ∘ Two high spacers (19a, 19b) extending in the X-direction on the two parallel sidewalls, ∘ Two low spacers (16a, 16b) extending in the Y-direction on the two sidewalls of the opening extending in said Y-direction, wherein the mask layer is exposed in an area of the bottom of the opening, said area being surrounded by the two low spacers (16a,16b) and by the two high spacers (19a,19b), - Removing the sacrificial structure selectively with respect to the spacers (19a, 19b), - Depositing a blocking material on the exposed area of the mask layer, - Using the spacers (19a, 19b, 16a, 16b) and the blocking material as a mask for patterning the intermediate layer and the mask layer, thereby creating a patterned mask on the layer of dielectric material, - Etching trenches (21a,21b) in the layer of dielectric material, in accordance with the patterned mask, - Filling the trenches (21a,21b) with an electrically conductive material and planarizing said material, thereby obtaining two colinear conductive lines (23a,23b) separated by a dielectric gap at the location of the blocking material. - producing a mask layer on a layer of said dielectric material formed on the substrate, - producing an intermediate layer on top of and in contact with the mask layer, - producing a sacrificial structure on the intermediate layer, the sacrificial structure comprising at least two parallel and mutually facing sidewalls of the structure with an elongate open area between said sidewalls, the open area extending in the X-direction of an orthogonal X-Y axis system in a plane parallel to the substrate, - by a lithography and etch process, producing an essentially rectangular opening in the intermediate layer, thereby locally exposing the mask layer, wherein ∘ the size of the opening in the Y-direction is self-aligned relative to the two parallel sidewalls, ∘ the size of the opening in the X-direction is defined by a mask pattern applied in the lithography and etch process, ∘ the size of the opening in the Y-direction is self-aligned relative to the two parallel sidewalls, ∘ the size of the opening in the X-direction is defined by a mask pattern applied in the lithography and etch process, - depositing a layer of spacer material conformally on the sacrificial structure and on the bottom and sidewalls of the opening, - etching back the spacer material so as to expose the top of the sacrificial structure, thereby creating: ∘ Two high spacers (19a, 19b) extending in the X-direction on the two parallel sidewalls, ∘ Two low spacers (16a, 16b) extending in the Y-direction on the two sidewalls of the opening extending in said Y-direction, wherein the mask layer is exposed in an area of the bottom of the opening, said area being surrounded by the two low spacers (16a,16b) and by the two high spacers (19a,19b), ∘ Two high spacers (19a, 19b) extending in the X-direction on the two parallel sidewalls, ∘ Two low spacers (16a, 16b) extending in the Y-direction on the two sidewalls of the opening extending in said Y-direction, wherein the mask layer is exposed in an area of the bottom of the opening, said area being surrounded by the two low spacers (16a,16b) and by the two high spacers (19a,19b), - Removing the sacrificial structure selectively with respect to the spacers (19a, 19b), - Depositing a blocking material on the exposed area of the mask layer, - Using the spacers (19a, 19b, 16a, 16b) and the blocking material as a mask for patterning the intermediate layer and the mask layer, thereby creating a patterned mask on the layer of dielectric material, - Etching trenches (21a,21b) in the layer of dielectric material, in accordance with the patterned mask, - Filling the trenches (21a,21b) with an electrically conductive material and planarizing said material, thereby obtaining two colinear conductive lines (23a,23b) separated by a dielectric gap at the location of the blocking material.