| 摘要 |
A method for manufacturing a semiconductor device is provided to improve precision of channel dimension of an EDMOS(Extended Drain Metal Oxide Semiconductor) device by forming a gate oxide layer using an isotropic etching. A nitride layer is deposited on a silicon substrate(200). A first trench is formed by using an isotropic etching through a chemical dry etching. A second trench is formed on the silicon substrate where the first trench is formed by using an anisotropic etching through a plasma etching. An oxide layer(210) is gap-filled in the first trench and the second trench. A first STI(Shallow Trench Isolation)(204a) and a second STI(206a) are formed by planarizing the oxide layer through a CMP(Chemical Mechanical Polishing). The nitride layer is removed. After a well(208) is formed between the second STIs through ion implantation, an oxide layer and a poly silicon layer are deposited on the silicon substrate where the well is formed. The poly silicon layer is patterned to form a gate(214). After an ion implantation is performed by using the gate as a mask, an impurity region(216) is formed.
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