| 摘要 |
PURPOSE: A method for fabricating an isolation layer of a semiconductor device is provided to prevent an electrical characteristic from being deteriorated by variation of an etch depth of a trench, by greatly reducing dependence upon an etch rate and by gently etching a silicon corner. CONSTITUTION: A pad oxide layer and a pad nitride layer are sequentially formed on a semiconductor substrate. A predetermined region of the pad nitride layer and the pad oxide layer is etched until the pad nitride layer and the pad oxide layer in a region having a broad pattern interval are completely eliminated. The pad nitride layer and the pad oxide layer in a region having a narrow pattern interval are completely removed while the semiconductor substrate is etched to make the broad and narrow regions have the same etch depth and the corner of the active region of the semiconductor substrate is round. The etch rates of the broad and narrow regions are made equal to etch a target depth of the semiconductor substrate so that a trench is formed. The inside of the trench is filled with an insulation material. The pad nitride layer, the pad oxide layer and the insulation material on the semiconductor substrate are planarized.
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