| 摘要 |
PURPOSE:To enable to form a microscopic active region in excellent reproducibility by a method wherein a field oxide film is formed in two separate times, the surface layer of the above is removed after formation of the field oxide film for preprocessing, and the second oxidization-resistant mask is coated, thereby enabling to reduce the infiltration of the field oxide film into an active region when a selective oxidization is performed. CONSTITUTION:The surface 15, covered by the first mask 13a composed of the exposed surface 14 of a semiconductor substrate 11, an oxide film 12 and a nitride film 13, is formed. Then, said surface 14 is converted into an oxide film 16 by performing thermal oxidization, and the semiconductor substrate 17 located on the edge part of the layer 13a is exposed by removing the surface layer. At this time, the film 16 is left as a thin oxide film 18. A nitride film 19 is formed on the substrate 17 part using films 12 and 18 as masks, and then a thick field oxide film 20 is grown by performing oxidization in a wet oxygen atmosphere. At this time, the infiltration of an oxide film 20 into the expected active region 21 is suppressed by the film 19. Subsequently, the films 12, 13 and 19 are removed, an active region 21 and a field region 22 are formed, and an element is formed in the region 21. |
