Maskless deposition of copper from an aqueous copper sulfate solution onto n-doped and p-doped Si is investigated. On p-doped Si substrates, microscopic(~10 μm) copper spots are deposited by using CW $Ar^+$ laser beam of wavelength 514.5nm. The proposed deposition mechanism is governed by the electric field resulting from the Galvanic potential of semiconductor-electrolyte junction. The spot diameter of copper is plotted as functions of laser power, irradiation time and HF concentration in electrolytic solution. Copper deposition on n-doped Si substrates is successful by using the second harmonic generated in a type I $KH_2PO_4$ crystal by passively Q-switched Nd:YAG laser(pulse width ~ 25nsec).
