| 摘要 |
A method of forming a bit line of a semiconductor device wherein an etch-stop nitride film, a trench oxide film and a hard mask nitride film are formed on a semiconductor substrate. The hard mask nitride film and the trench oxide film are etched to a limited etch thickness of a photo mask. The remaining trench oxide film is etched using the hard mask nitride film as a mask, thus forming a trench. The etch-stop nitride film and the hard mask nitride film are etched on condition that an oxide film has a high selectivity with respect to a nitride film. Accordingly, the loss of a top surface of the trench oxide film can be minimized and a bit line can be formed to have a uniform height. In accordance with the invention, bit line resistance and capacitance variation can be reduced and the reliability of a device can be improved.
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