| 摘要 |
A method for fabricating a semiconductor device is provided to guarantee an interval between gate lines even after a subsequent oxide process by forming silicide of a negative profile having an undercut type. A gate oxide layer(25) is formed on a silicon substrate(21). Polysilicon(26), silicide(27) and a hard mask nitride layer(28) are sequentially stacked on the gate oxide layer. A gate mask is formed on the hard mask nitride layer. The hard mask nitride layer is etched by using the gate mask as an etch barrier. While the silicide is etched by using the gate mask as an etch barrier, polymer generated after the hard mask nitride layer is etched is removed wherein the etched surface of the silicide has a negative profile of an undercut type. In etching the silicide, polymer generation control gas added to fluorine gas is used. The gate mask and etch residue of the silicide are removed. The polysilicon is etched to form a gate line by using the hard mask nitride layer as an etch barrier. A gate re-oxidation process is performed to oxidize the polysilicon and the etched surface of the silicide.
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