| 摘要 |
PURPOSE:To enhance the switching speed of a semiconductor integrated circuit to be formed by forming a thick oxidized film on an isolation region, thereby reducing the capacity between the first layer wiring and a semiconductor substrate on the isolation region. CONSTITUTION:A window is opened at a dioxidized silicon film 15, a window is then opened at a polycrystalline silicon layer 14, and acceptor impurity ions are implanted. Then, the layers 15, 14 are removed, and a polycrystalline silicon layer 14' is allowed to remain. With the layer 14' as a mask the layers 13, 14, 12 are further etched and removed. As a result, the nitrided silicon layer 12' and the nitrided silicon layer 13' are allowed to remain. Subsequently, when a field oxidized film 16 is formed by selectively oxidizing with the layer 13' as a mask, a sufficiently thick oxidized film is formed on the isolation region. Then, electrode wirings are formed by a conventional technique. Thus, a capacity C between the first layer wirings 21 and the substrate 1 can be reduced. |
