| 摘要 |
PURPOSE: A method for forming an isolation layer of a semiconductor device is provided to prevent degradation of device characteristics caused by insufficient corner rounding at edges of the isolation layer, without using additional equipments and with reduced process steps. CONSTITUTION: After a pad oxide layer(12) and a pad nitride layer(13) are sequentially deposited on a silicon substrate(11), a shallow trench is formed through isolation masking and etching processes. Next, after the first pre-cleaning process, a wall oxide layer with a predetermined thickness is formed on an inner wall of the trench. Next, a high density plasma oxide layer(15) is formed in the trench and on the pad nitride layer(13). Next, a chemical mechanical polishing process is performed by using the pad nitride layer(13) as a barrier, and then the high density plasma oxide layer(15) is removed by performing the second pre-cleaning process so as to expose the pad nitride layer(13). Thereafter, oxygen gas is supplied to round off the edges of the trench by a dry oxidation process, and continuously the high density plasma oxide layer(15) is densified by an annealing process.
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