Disclosed is a method of etching a metal barrier layer and a metal layer. The method includes forming the metal barrier layer and the metal layer on a substrate, and using an etching composition to etch the metal barrier layer and the metal layer. The etching composition may include an oxidant selected from nitric acid, bromic acid, iodic acid, perchloric acid, perbromic acid, periodic acid, sulfuric acid, methane sulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid, or a combination thereof, a metal etching inhibitor including a compound expressed by Chemical Formula 1, and a metal oxide solubilizer selected from phosphoric acid, phosphate, carboxylic acid having 3 to 20 carbon atoms, or a combination thereof.