Structure of a mask ROM device on a semiconductor substrate having a cell area for coding

摘要

The present invention includes NMOS devices on a NMOS device area and coded NMOS devices on a cell area. Isolation structures are formed between the NMOS devices and between the coded NMOS devices. N conductive type bit lines are formed under first isolation structures. A coding region is formed on the cell area between two coded NMOS devices and under a second isolation structure. Spacers are formed on the side walls of the NMOS devices and the coded NMOS devices and an anti-reflective coating layer is formed on the NMOS devices and the coded NMOS devices.