SEMICONDUCTOR DEVICE MANUFACTURING METHOD

PROBLEM TO BE SOLVED: To provide a manufacturing method which is unlikely to generate voids inside an embedded film in a trench.SOLUTION: A semiconductor device manufacturing method comprises: a process of sequentially forming an insulation film 102, a stopper film 103 and a hard mask layer 104 on a principal surface of a silicon substrate 101; a process of forming on the hard mask layer 104, a mask pattern 111 having an opening 111a; a process of performing isotropic etching on the hard mask layer 104 and the stopper film 103 through the opening 111a in a manner that an etching rate for the hard mask layer 104 is higher than an etching rate for the stopper film 103; a process of performing anisotropic etching on the insulation film 102 through the opening 111a to form a trench 105; a process of removing the mask pattern 111; a process of filling the trench 105 with an insulation material to form an embedded film 106; and a process of removing the embedded film 106 and the hard mask layer 104 until the stopper film 103 is exposed.