| 摘要 |
PURPOSE:To obtain an ion injected mask as selectively oxidized mask by patterning a double layer made of an Si3N4 film and a polycrystalline Si film with a resist film as a mask, plasma treating it and further baking the resist film. CONSTITUTION:The pattern of a double layer made of an Si3N4 film 13 and a polycrystalline Si film 14 is formed on an SiO2 film 12 formed on an Si substrate 11. The pattern is formed by so etching it with a resist film 15 as a mask in a slightly sidewise etching manner. After it is treated in an oxygen plasma atmosphere, it is baked to depend the resist 15. Subsequently, with the resist 15 as a mask impurity ions 17 are injected, the resist is then removed, and is selectively oxidized, thereby forming a stopper 8. Since the stopper 8 is contained directly under a field oxidized film 19 in this manner and is not superposed with the other element region 20, it can prevent the decrease in the withstand voltage. |
