| 摘要 |
PURPOSE: A method for forming an isolation layer of a semiconductor device is provided to be capable of preventing moats from being generated at the upper edge portion of the isolation layer for improving the reliability of forming process and electrical characteristics of the semiconductor device. CONSTITUTION: A pad oxide layer and a pad nitride layer are sequentially formed on a semiconductor substrate(301). A trench is formed by selectively etching the pad nitride layer, the pad oxide layer, and the semiconductor substrate. The trench is filled with an insulation layer(306). An etch stop sacrificial layer is formed on the entire surface of the resultant structure for completely filling the trench. A CMP(Chemical Mechanical Polishing) process is carried out on the etch stop sacrificial layer of the pad nitride layer. The etch stop sacrificial layer of buckhorn type structure remains by removing the pad nitride layer. Then, an isolation layer(310) is completed by carrying out a three-step oxidation process and a cleaning process on the resultant structure.
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