Spin‐coated solid films of the gold‐cluster compound Dodeca‐(triphenylphosphine), hexa(chloro)pentapentacontagold Au55(PPh3)12Cl6are irradiated with a focused 20‐keV Ga+focused‐ion beam. The writing speeds on the substrate were ranging from 50 up to 2000 &mgr;m/s. This treatment locally decreases the solubility of the metalorganic precursor layer in CH2Cl2. Removal of the nonirradiated part of the surface layer with this solvent, followed by thermal decomposition of the remaining metalorganic nanostructures, leads to conducting gold lines. The width (150–360 nm) and height (20–80 nm) of these metallic lines depend on the ion dose and the original film height of the gold compound. The possible interactions leading to the fixation are briefly discussed.