Patent ID: 6569736
Filing Date: 2003-05-27
Classification: H01L

Abstract:
A method for forming square polysilicon spacers on a split gate flash memory device by multi-step polysilicon etch comprising the steps of:providing a pre-processed silicon substrate that has a split gate flash memory device formed thereon; depositing a polysilicon layer on top of said pre-processed silicon substrate; forming a sacrificial layer on top of the polysilicon layer; removing said sacrificial layer on top of the flash memory device, while leaving the sacrificial layer on the side of the flash memory device intact; etching away the polysilicon layer exposed on top of the split gate flash memory device; removing residual sacrificial layer on the side of the split gate flash memory device; and etching away the residual polysilicon layer anisotropically leaving square cornered polysilicon spacers on said split gate flash memory device.