| 摘要 |
PURPOSE:To enable the surface of an Si substrate to be finely and uniformly roughened to a level of the order of Angstrom and accurately controlled in roughness independently of the form of an Si film or an Si layer on the surface of the Si substrate without making a manufacturing process complicated or a manufacturing cost increasing in a trench or stacked-type cell structure of a DRAM. CONSTITUTION:An Si substrate 20 is dipped into a cleaning liquid such as SCl or the like which contains metal substance such as Fe, Ni, Cu, Zn, Al, or Cr of the order of ppb to clean its surface, the surface of the substrate 20 is dried out, and then a silicon oxide film 22 which contains metal 21 is formed on the surface of the substrate 20, and the surface of the Si substrate 20 where the silicon oxide film 22 is formed is subjected to an isotropic etching process wherein Si can be etched at a high selection ratio to an silicon oxide film to produce micro irregularities. |
