DRAM OF COB STRUCTURE AND MANUFACTURE THEREOF

PROBLEM TO BE SOLVED: To increase a capacitor's capacitance without enlarging a step to a peripheral circuit part and with less photolithography processes required for capacitor formation, by, related to a DRAM of COB(capacitor over bit line) structure, forming a stack electrode in the region below a bit line as well. SOLUTION: A word line 2 is protected with a nitride film, which is covered with an inter-layer insulating film 5, and holes of a bit line contact and capacitor contact are formed at the same time at the inter-layer insulating film 5. Then a polysilicon is embedded to form the bit line contact and a capacitor contact 6 at the same time before a bit line 7a is patterned, and further a side wall insulating film comprising a nitride film is formed on the side surface of the bit line. An insulating film 10 is formed on the inter-layer insulating film 5, which is so etched that the remain between the above the bit line and word line, a conductor layer 12 of polysilicon being formed thereafter.