| 摘要 |
PURPOSE:To prevent the surface defect, surface roughness, etc., of a substrate by applying an oxide film onto a substrate surface, on which a transistor is formed, before a process etching the whole surface. CONSTITUTION:A trench 6 is shaped into an active region in a semiconductor substrate 1, and a dielectric film 7 with a nitride film 15 is applied and formed onto the surface of the trench 6. A conductive film 8 is buried into the trench 6 in specified depth, the dielectric film 7 is removed through etching, using the film 8 as a mask, the upper section of the surface of the substrate 1 is thermally oxidized, and oxide films 17, 18 in predetermined thickness are shaped. The oxide film 18 on the conductive film 8 is gotten rid of selectively through anisotropic etching while the upper section of the conductive film 8 is taken off, the section of the dielectric film 7 is exposed and an exposed section is removed selectively, and the surface of the substrate 1 is exposed. A polysilicon film 9 is applied and formed onto the substrate 1, the whole surface is gotten rid of through etching, leaving the exposed surface of the substrate 1 and a section crossing on the conductive film 8, and the oxide film 17 is taken off. Accordingly, a surface defect, surface roughness or the like at the time of the etching of the whole surface of the polysilicon film 9 can be prevented. |
