Apparatus and methods for forming self-assembly arrays of substances, such as nanoparticles, on a substrate are disclosed. The apparatus may include a substrate supporting a liquid composition including the substance and a solvent, and a removable micro-mold placed over the substrate and the liquid composition. To form the self assembly arrays of the substance, the solvent may be evaporated through at least one evaporation channel formed between the micro-mold and the substrate. The evaporation channel may be adjustable by subjecting the micro-mold to a positive pressure.