Patent ID: 6821841
Filing Date: 2004-11-23
Classification: H01L

Abstract:
A method for fabricating a mask read-only-memory with diode cells, comprising:providing a semiconductor substrate; forming a buried diffusion layer with a first conductivity in a top portion of said semiconductor substrate; forming a plurality of shallow trench isolation regions in said semiconductor substrate and then making said buried diffusion layer to a plurality of bit lines; forming an interlayer dielectric layer over said buried diffusion layer and said shallow trench isolation regions; forming a photoresist layer with a mask read-only-memory code pattern on said interlayer dielectric layer; performing an anisotropic etching process to form openings in said interlayer dielectric layer unto the exposed regions of said buried diffusion layer using said photoresist layer as an etching mask; removing said photoresist layer; performing ion implantation to form a diffusion region with a second conductivity opposite to said first conductivity in each of said exposed regions of said buried diffusion layer; forming a contact plug in each said opening unto said diffusion region; and forming a conductive layer on said interlayer dielectric layer for serving as word lines.