Abstract: This invention is related to providing a bonding method for flip chips in which the circuit part is oriented to be face-down on a substrate after bonding bumps are formed on the semiconductor chip namely, forming Au bumps by Au wire ball bonding employing a wire ball bonding device onto aluminum bond pads of the semiconductor chips; coating the Au bumps with Sn/Pb alloy bumps also by wire ball bonding using a wire ball bonding device; with or without re-forming the Sn/Pb alloy bumps into a desired ball-shape by performing a heat treatment in a furnace after an activation solvent is applied to the Sn/Pb alloy bumps; and bonding (by the heat treatment in the furnace) the substrate to the coated bumps containing chip by a heat treatment in the furnace.