| 摘要 |
PURPOSE: A method for fabricating an isolation layer of a semiconductor device is provided to prevent a void from being formed in a trench by using boron phosphorous silicate glass(BPSG) having an excellent gap-fill characteristic. CONSTITUTION: A pad oxide layer(200a) and a nitride layer(300a) are formed on a semiconductor substrate(100). The nitride layer, the pad oxide layer and the substrate are selectively removed to form a trench(350). A low-pressure tetra-ethyl-ortho-silicate undoped-silicate-glass(LP TEOS USG) layer(400b) is formed on the inner surface of the trench and on the nitride layer. A BPSG layer(500b) is formed on the substrate including the trench having the LP TEOS USG layer. A chemical mechanical polishing(CMP) process is performed on the BPSG layer and the LP TEOS USG layer to expose the nitride layer. The substrate is cleaned to recess the BPSG layer to the inside of the trench. A gap-fill material layer(600a) is formed on the substrate so that the BPSG layer fills the recessed trench. A CMP process is performed on the gap-fill material layer to expose the nitride layer.
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