| 摘要 |
PURPOSE: A method for manufacturing an isolation layer of a semiconductor device is provided to be capable of preventing hump and fringing field at corner portions of a trench. CONSTITUTION: A pad oxide and nitride layer are sequentially formed on a silicon substrate(100). By selectively etching the pad nitride layer, a trench active region is defined. The pad oxide layer is widely etched by full back etching using the pad nitride pattern as a mask. A trench is formed by multi-step etching while applying different bias by using the pad nitride and oxide pattern as a mask. A sacrificial oxide layer(150) is formed at inner walls of the trench by wet-oxidation processing. Then, an isolation layer(170) is formed in the trench.
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