| 摘要 |
A ROM semiconductor device and a method of manufacturing that device on a semiconductor substrate comprises the steps of forming a blanket word line layer over the device with a reverse word line mask over the word line layer, the word line mask comprising a parallel array of mask strips, forming a ROM code mask over the reverse word line mask, the ROM code mask having a ROM code opening centered between a pair of the mask strips. A code implant dopant is ion implanted through the ROM code opening down into a doped region in the substrate below the ROM code opening. The ROM code mask is removed. A word line mask is formed comprising complementary mask strips between the mask strips of the reverse word line mask followed by removal of the reverse word line mask, etching the word line layer to form a parallel array of word lines beneath the complementary mask strips, and forming a blanket layer of dielectric material over the device.
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