Two different methods of laser induced copper deposition on Si substrates were investigated. One was the photovoltaic deposition from an aqueous copper sulfate solution and the other was deposition by the photothermal decomposition of a solid copper acetate film, using a cw $Ar^+$ laser (514.5nm). Both resulted in the formation of copper spots and lines. The characteristics of the deposits formed by these two methods were compared. Line width and spot diameter were plotted as functions of laser power, scanning speed, irradiation time. Writing speed for photovoltaic deposition was lower than that for deposition by the photothermal decomposition. The surface structures of the deposits formed by the photovoltaic deposition were more smooth than those formed by the photothermal decomposition. The laser power density necessary for the photovoltaic deposition ($~10^2 W/cm^2$) was found to be much lower than that for photothermal decomposition($~10^5 W/cm^2$).
