Etchant composition, patterning conductive layer and manufacturing flat panel, display device using the same

A method of patterning a conductive layer, the method comprising;

• forming a first conductive layer on a substrate, wherein the conductive layer includes at least one of Al, Al alloy, and Mo;
• patterning a photoresist layer by photo-exposure;
• and
• etching the conductive layer using the patterned photoresist layer as an etch mask;
• wherein an etchant composition used to etch the conductive layer includes a phosphoric acid, a nitric acid, an acetic acid, an acetate compound, and water.

A method of manufacturing a flat panel display device, the method comprising;

• providing a substrate;
• forming a first conductive layer on the substrate;
• patterning the first conductive layer to form a gate line and a gate electrode;
• forming a semiconductor layer on the substrate corresponding to the gate electrode;
• forming a second conductive layer on the semiconductor layer;
• patterning the second conductive layer to form source/drain electrodes;
• wherein the gate electrode and the source/drain electrodes are patterned using one etchant composition including phosphoric acid, a nitric acid, an acetic acid, an acetate compound, and water.