Patent ID: 6309979
Filing Date: 2001-10-30
Classification: H01L

Abstract:
A method for protecting a semiconductor substrate from charging damage from plasma-induced current through said substrate while etching, in a plasma in a high density plasma chamber, through a selected portion of a conductive layer above said substrate, comprising:providing said semiconductor substrate, said semiconductor substrate having a surface, said surface having a gate oxide region covered by a thin gate oxide layer, said surface having a field oxide region covered by a field oxide layer, and said surface having a first region, said field oxide region being located between said gate oxide region and said first region, said conductive layer covering said substrate and laying over said thin gate oxide, over said field oxide and over said first region of said surface of said substrate;providing an etch mask over said conductive layer, said etch mask protecting said conductive layer over said thin gate oxide region said etch mask having an opening exposing said selected portion of said conductive layer, said selected portion of said conductive layer extending over said first region and over a portion of said field oxide region;performing a bulk etch partially through said selected portion of said conductive layer using a first power setting for a plasma generating source of said high density plasma chamber and terminating said bulk etch while a remainder of said selected portion of said conductive layer remains to be etched; andperforming a clearing etch through said remainder of said selected portion of said conductive layer using a second power setting for said plasma generating source, thus exposing said first region of said surface of said substrate to said plasma while using said second power setting, said second power setting being substantially minimized to reduce said charging damage by reducing said plasma-induced current flowing from said conductive layer through one of said thin gate oxide region and through said substrate to said first region of said surface of said substrate.