| 摘要 |
PURPOSE:To flatten the surface of a semiconductor substrate by a method wherein the silicon part, with which a selective oxide film is protuberantly formed, is removed by etching in advance, and the steps of the selective oxide film and the protrusion are removed by performing a selective oxidization again. CONSTITUTION:An oxide film 10 and the first silicon nitride film 11 are formed on a silicon substrate 9, and an interlayer isolation region is formed by removing a part of the nitride film 11 and the oxide film 10. The interlayer ioslation region is selectively oxidized, an oxide film 14 is removed by performing an etching, and an oxide film 16 is formed. The second silicon nitride film 17, which will be turned to an oxidization mask, is formed on the whole surface, the second silicon nitride film 19 is selectively left on the silicon substrate side of the bird's beak part by performing an etching on the second silicon nitride film 17 using the first silicon nitride film pattern 11 as a mask, and a selective oxide film 20 is formed by oxidizing the silicon substrate 13 using the nitride film 19 as a mask. |
