Patent ID: 8592284
Filing Date: 2013-11-26
Classification: H01L

Abstract:
1. A manufacturing method of a semiconductor device, comprising: making a trench in a main surface of a semiconductor substrate; oxidizing a wall surface of the trench in an atmosphere containing an active oxidizing species, thereby forming a first oxide film on the wall surface; forming an embedded conductive film so as to be embedded into the trench, the wall surface of which being covered with the first oxide film; oxidizing the embedded conductive film in an atmosphere containing an active oxidizing species, thereby forming a second oxide film; and forming a third oxide film having tensile stress over the second oxide film, the third oxide film formed only right over the embedded conductive film, wherein in the oxidizing the embedded conductive film, a tapered region, having a width which is made smaller in a direction extending from where the first oxide film is jointed to the second oxide film at an upper portion of the embedded conductive film towards a lower portion of the embedded conductive film, is formed in the first oxide film, and wherein in the forming the embedded conductive film, an upper surface of the embedded conductive film is lower than the main surface of the semiconductor substrate.