The substrate is provided with a layer of first material, a first etching mask, a covering layer and a second etching mask. The covering layer has a covered main area and an uncovered secondary area. The secondary area of the covering layer is partially etched via the second etching mask to form a salient pattern. Lateral spacers are formed around the salient pattern defining a third etching mask. The second etching mask is eliminated. The covering layer is etched by means of the third etching mask to form a salient pattern in the covering layer and to uncover the first etching mask and the first material. The layer of first material is etched to form the pattern made from the first material.