| 摘要 |
A method for improving a trench profile of an STI is provided to prevent stress from being generated in a corner portion of the STI by executing corner rounding at upper and lower of a trench at the same time. A pad insulator is formed on a silicon semiconductor substrate(200). By etching the pad insulator, a part of the substrate to form an STI(Shallow Trench Isolation) is exposed. An oxide layer formed by the exposed result on the substrate is removed. After the remove process, a trench(220) is formed on the exposed substrate using plasma including HBr, O2, and Cl2. The taper angle of the trench is under 80 degrees.
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