| 摘要 |
PURPOSE:To improve the superposing accuracy of the pattern for the titled device by a method wherein the warpage of a semiconductor substrate, which will be generated when a field oxide film is formed on the main surface of the semiconductor substrate, is reduced using a selective thermal oxidizing method. CONSTITUTION:An SiO2 film 12 is formed on both sides of the Si substrate 11, and an Si3N4 film 13 is formed by deposition on the film 12. On the film 13, the photo resist pattern 15 corresponding to the active region 14, to be formed on the substrate 11, is formed. A selective etching is performed on the region 14 using the pattern 15 as a mask, and a high density P type impurity ion is shallowly implanted in the main surface of the substrate 11. Then, the pattern 15 is removed, and an Si3N4 pattern 13 is formed on the film 12. A thermal oxidation is selectively performed on the region whereon no pattern 13' is covered, and a field oxidation film 17 is formed. Accordingly, the stress which will be given from the back side of the substrate 11 can be lessened and the warpage of the substrate can also be reduced. |
