A process for producing two interleaved patterns on a substrate uses photolithography and etching to produce, on the substrate, a first pattern of first material protruding regions separated by recessed regions. A non-conformal deposition of a second material on the first pattern forms cavities in the recessed regions of the first pattern. These cavities are opened and filled with a third material. The second material is then removed, and the remaining third material forms a second pattern of third material protruding regions, wherein the second pattern is interleaved with the first pattern.