| 摘要 |
A method for manufacturing a semiconductor device is provided to restrain the generation of notching in a polysilicon etching process and to obtain uniform characteristics from the semiconductor device by controlling process conditions in an over etch process. A gate oxide layer(110), a polysilicon layer(125) and an ARC(Anti-Reflective Coating)(135) and a photoresist pattern are sequentially formed on a semiconductor substrate(100). The ARC is selectively etched by using the photoresist pattern as an etch mask. Two-step main etching processes are performed on the polysilicon layer under first predetermined conditions by using the photoresist pattern as an etch mask. An over etch process is then performed on the gate oxide layer in a source power range of 300 to 800 W and in a bias power range of 20 to 100 W by using the photoresist pattern as an etch mask. The over etch process is performed for 20 to 80 second under a predetermined pressure condition of 40 to 80 mT by flowing HBr gas of 200 to 400 sccm and HeO2 gas of 10 to 40 sccm.
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