A method to fabricate an imprint mould in three dimensions including at least: a) forming at least one trench, of width W and depth h, in a substrate, thereby forming three surfaces including, a bottom of the at least one trench, sidewalls of the at least one trench, and a remaining surface of the substrate, called top of the substrate; b) forming alternate layers in the at least one trench, each having at least one portion perpendicular to the substrate, in a first material and in a second material which can be selectively etched relative to the first material; and c) selectively etching said portions of the layers perpendicular to the substrate.