Patent ID: 6146949
Filing Date: 2000-11-14
Classification: H01L

Abstract:
A method for forming mask read-only memories, said method comprises:forming a gate oxide layer on a semiconductor substrate;forming a polysilicon layer on said gate oxide layer;forming a masking layer on said polysilicon layer;patterning said masking layer and said polysilicon layer to define gate structures;forming spacers on sidewalls of said patterned gate structures;Implanting first conductive type dopant into said semiconductor substrate by using said masking layer and said spacers as a mask to form buried bit lines in said semiconductor substrate between said gate structures;coating a sacrificial layer on said semiconductor substrate;removing a portion of said sacrificial layer on a top surface of said gate structures;removing said masking layer;forming a conductive layer along a surface of said residual sacrificial layer, spacers and polysilicon layer; anddefining word lines by etching said conductive layer.