US Patent 7132334 Methods of code programming a mask ROM device

A method of code programming a mask read only memory (ROM) is disclosed. A method of the present invention includes forming a layer of developable anti-reflective coating over a plurality of code openings located on a substrate of a ROM device. The plurality of code openings are typically elements of a first code, or pre-code, pattern, and a portion of the developable anti-reflective coating layer is removed or processed to define a second code, or real-code, pattern of the device. The method may be practiced by applying and patterning a layer of photoresist material over the developable anti-reflective coating to form a second code pattern, and then removing portions of the developable anti-reflective coating that remain exposed beneath the patterned photoresist material.