| 摘要 |
PROBLEM TO BE SOLVED: To prevent punch-through of a wiring layer due to the formation of contact holes, and to reduce contact resistance. SOLUTION: Stack polysilicon films 7 are patterned, and dummy patterns 8 are formed in a part where a shallow contact hole 12 is opened so that they surround the contact hole 12. A capacitive oxide film 9 and a capacitive polysilicon film 10 which are a capacitive electrode are deposited on a BPSG oxide film 5 and the stack polysilicon film 7, and then they are patterned. A BPSG oxide film 11 which is to become an interlayer insulating film is formed on the capacitive polysilicon film 10 and is flattened through chemical- polishing method(CMP). The contact holes 12 and 13 which are different in depths are opened at the same time for conducting a diffused layer 3 and the capacitive polysilicon film 10. Thus with this method, punch-through of a wiring layer due to the formation of the contact holes is prevented, and contact resistance can be reduced. |
