Patent ID: 6174818
Filing Date: 2001-01-16
Classification: H01L

Abstract:
A process for etching a narrow line in polysilicon, comprising:providing a layer of polysilicon on a substrate;depositing a layer of silicon oxynitride on said layer of polysilicon;depositing a layer of silicon oxide on the layer of silicon oxynitride;coating the layer of silicon oxide with a layer of photoresist;patterning the photoresist to form a narrow line;using said photoresist pattern as a mask, etching all unprotected silicon oxide and silicon oxynitride, thereby forming a hard mask;removing all photoresist;using the hard mask, fully etching all unprotected polysilicon in a manner whereby all silicon oxide in the hard mask is removed and some thickness of silicon oxynitride in the hard mask remains;removing any polymer residue present; andthen removing all remaining silicon oxynitride.