Nano-scale Cu metal patterning was achieved by the use of an atomic force microscope. When the scanning with the cantilever of atomic force microscope (AFM) covered with the solid electrolyte was carried at a negative voltage, the Cu metal was deposited on TiO2 substrates. The Cu metal on TiO2, a glass and Si substrates was absorbed at the positive voltage. The deposition and the absorption of Cu could be repeated and carried out at room temperature without a specific treatment. The letters "Y" and "T" were written with 50 nm resolution by the scanning. The reaction between the tip of the cantilever and substrate is a simple electrochemical reaction. (c) 2004 Elsevier B.V. All rights reserved.