A method of manufacturing a semiconductor device is disclosed. In one embodiment, the method comprises: forming a gate stack on a substrate; etching the substrate on both sides of the gate stack to form C-shaped source/drain grooves; and wet-etching the C-shaped source/drain grooves to form Σ-shaped source/drain grooves. With this method, it is possible to effectively increase stress applied to a channel region, to accurately control a depth of the source/drain grooves, and to reduce roughness of side walls and bottom portions of the grooves and thus reduce defects by etching the C-shaped source/drain grooves and then further wet-etching them to form the Σ-shaped source/drain grooves.