Polysilicon mask for etching thick insulator

摘要

An improved method is disclosed for etching the thick field insulator films of silicon-oxy-nitride, during the fabrication process of metal oxide semiconductor (MOS) devices, wherein a polycrystalline silicon etch mask is used in conjunction with an acid etchant to etch the gate and interconnect openings through the thick field insulator to the source, gate and chain regions of the MOS devices for a memory array.