A method of forming gate conductor structures. A substrate having thereon a gate electrode layer is provided. A multi-layer hard mask is formed overlying the gate electrode layer. The multi-layer hard mask comprises a first hard mask, a second hard mask, and a third hard mask. A photoresist pattern is formed on the multi-layer hard mask. A first etching process is performed to etch the third hard mask, using the photoresist pattern as a first etch resist, thereby forming a patterned third hard mask. A second etching process is performed to etch the second hard mask and the first hard mask, using the patterned third hard mask as a second etch resist, thereby forming a patterned first hard mask. A third etching process is performed to etch a layer of the gate electrode layer, using the patterned first hard mask as a third etch resist.