This publication discloses a method for forming electrically conducting structures (102) on a substrate (100). According to the method nanoparticles (101) containing conducting or semiconducting material are applied on the substrate (100) in a dense formation and a voltage is applied over the nanoparticles so as to at least locally increase the conductivity of the formation. According to the invention, the voltage is high enough to cause melting of the nanoparticles in a breakthrough-like manner. With the aid of the invention, small-linewidth structures can be created without high-precision lithography.