| 摘要 |
PURPOSE: A method for fabricating a shallow trench for semiconductor device isolation is provided which improves the reliability and the fabrication yield of the semiconductor device by preventing a silicon wafer on a top edge of a trench side wall from being revealed by an over-etch and a misalignment error of a mask. CONSTITUTION: According to a method for fabricating a shallow trench for semiconductor device isolation, in case of etching a nitride film(13) with a photoresist pattern as a mask in a fabrication process of a shallow trench, the revealed nitride film is first-etched with the photoresist pattern as a mask and at the same time a polymer is formed on both side walls of the etched nitride film, and then the process of isotropic etching of the remained nitride film is repeated until the top width of the etched nitride film is wider than the bottom width. Thus, the top width of an insulation film(15) buried in the trench is formed wider than the top width of the trench. Thus, the method prevents a silicon wafer(11) on a top edge of the trench side wall from being revealed by giving a margin as to the etch of the insulation film by the misalignment error of the mask and the continued cleaning process.
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