| 摘要 |
PURPOSE:To curb the emission of impurity material by an impurity-implanted silicon oxide film in a heat treatment process by a method wherein an impurity- free silicon oxide film is formed on the impurity-implanted material filling a groove in a structure incorporating an isolating groove. CONSTITUTION:After the formation of a recess 12 on a semiconductor substrate 11, a silicon oxide film 13 is formed in the recess 12. Next, etch-back is accomplished, rendering the silicon oxide film 13 inside the recess 12 a little lower than the surface of the substrare 11. A process follows of forming a silicon oxide film 14 free of impurities on the entire surface and of effecting etch-back for the removal of the oxide film 14 except the portion in the recess 12. This results in the retention of the impurity-free silicon oxide film 14 in the upper portion of the recess 12. Semiconductor in this design is protected from advance effects during a heat treatment process which in other designs will develop due to emission of impurities out of the silicon oxide film 13 remaining in the recess 12. |
