| 摘要 |
PURPOSE:To prevent a bird-beak and/or a bird-head from being formed and to provide the semiconductor device with higher density, by constituting an oxide film to be formed in a concave on the surface of the semiconductor substrate by a low-temperature oxidizing film. CONSTITUTION:On one face of a silicon semiconductor substrate 1, a high- temperature oxidizing film 2 is formed, on which a silicon nitride film 3 is deposited. The oxide film 2 and silicon film 3 are selectively etched to form an opening serving as an element separating region. The surface of the substrate 1 exposed in the opening is etched to form a concave 1a with a given depth therein. On the entire face including the silicon film 3, a low-temperature oxidizing film 4 is deposited so as to fill approximately the concave 1a. A resist film 5 is adhered on the oxide film 4 so as to thicken only on a concave on the oxide film 4 corresponding to the concave 1a. Under a condition that the etching speed of the oxide film 4 is larger than that of the resist film 5, the resist film 5 and the oxide film 4 are etched. The resist film 5a being left on the oxide film 4 is then removed.
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