| 摘要 |
PURPOSE: A method for forming an isolation layer of a semiconductor device is provided to provide as big as possible active region from unit area to improve the operation margin. CONSTITUTION: The method includes following steps. At the first step, a photoresist layer is formed on the front surface of the semiconductor substrate and is selectively patterned to remove device isolation regions. At the second step, exposed semiconductor substrate is etched into a predetermined depth by using the patterned photoresist layer as a mask to form a trench. At the third step, impurity ions are injected into the trench to increase the oxidation speed. At the forth step, a heat oxide layer is formed on the front surface including the trench by performing heat oxidation operation. At the fifth step, BPSG (borophosphosilicate glass) layer is vaporized on the front surface, and is etched back to form a device isolation layer(27).
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