Method for fabricating mask ROM with self-aligned coding

摘要

A method for fabricating a Mask ROM with self-aligned coding is described. A plurality of buried bit lines are formed in a substrate, and then a plurality of word lines are formed on the substrate crossing over the buried bit lines with first blocking strips thereon. A plurality of second blocking strips are formed between the word lines and between the first blocking strips, and then the first blocking strips are patterned into an array of blocking bumps, which define a plurality of pre-coding windows with the second blocking strips. A coding mask layer is formed on the substrate with a plurality of coding windows therein exposing selected pre-coding windows, and then a coding implantation is performed to form implanted coding regions in the substrate under the selected pre-coding regions exposed by the coding windows. The coding mask layer is then removed.