| 摘要 |
PURPOSE: A method for manufacturing a dual silicon substrate using a bird's beak phenomenon is provided to increase uniformity of substrate thickness, by effectively compensating for a dishing effect occurring in the surface of the semiconductor substrate. CONSTITUTION: A pad oxide layer, a pad nitride layer and a hard mask layer are sequentially formed on a semiconductor substrate. The hard mask layer, the pad nitride layer and the pad oxide layer are etched to expose the substrate in an isolating region. The exposed semiconductor substrate is etched to form a trench by using the hard mask layer, the pad nitride layer and the pad oxide layer as a mask. A field oxide layer is grown on the lower surface of the trench. An isolating layer(18) is formed in the trench. The pad nitride layer and the pad oxide layer are removed. A buried oxide layer(19a,19b) is formed on the semiconductor substrate having the isolating layer and on a base substrate(20), respectively, to bond the semiconductor substrate and the base substrate. The surface of the semiconductor substrate is polished by the first chemical mechanical polishing(CMP) process using the isolating layer as a polishing stop layer. The semiconductor layer is polished to form a semiconductor layer of a predetermined thickness by the second CMP process.
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