| 摘要 |
A method for forming an isolation layer in a semiconductor device is provided to improve a bottom-up phenomenon from the bottom of a trench and reduce an interval of deposition time of an insulation layer by changing the shape of the trench into a V-shape. A hard mask layer is formed on a semiconductor substrate(31) having an active region and an isolation region. By using the hard mask layer as an etch barrier, the substrate is etched to form a trench(34) of a V shape. A first insulation layer(37a) is deposited in the trench by increasing bias power in a condition of HF power of 500~5000 W. A second insulation layer(37b) is deposited on the first insulation layer by decreasing bias power in a condition of HF power of 100~4000 W to completely fill the trench. A CMP process is performed on the first and the second insulation layers to expose the hard mask layer. The hard mask layer is eliminated. The hard mask layer can be made of a stack structure of a pad oxide layer and a pad nitride layer.
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