A novel masking technique against polymer deposition based on High Intensity Focused Ultrasound (HIFU) irradiation was developed for the first time With this in mind a variety of background salts were tested Sodium salicylate was found to be the most effective electrolytic medium for pyrrole sonoelectropolymerization on copper as it leads to a very efficient passivating oxide layer preventing copper dissolution while enabling polymer formation independently from sonication In such a medium high frequency ultrasound greatly refines surface structure and a slight increase in doping level is observed Finally It was proved that focused ultrasound increases copper dissolution in sodium oxalate electrolyte while preventing polypyrrole deposition A selected zone on the copper substrate was thus irradiated by the focused ultrasound beam to protect it from polymerization In a second stage a self-assembled monolayer was deposited on this polymer-free area to create a surface biphased substrate This type of masking technique can be proposed as an interesting alternative to lithography as it is easier to carry out and allows chemical waste reduction Crown Copyright (C) 2010 Published by Elsevier Ltd All rights reserved