| 摘要 |
PURPOSE:To make a high density integration dynamic type RAM (DRAM) without degrading microstructural memory cells in reliability by a method wherein an element isolating/insulating film on a capacitor trench side wall has a double layer structure of different insulating films and a capacitor trench is formed in contact with the element isolating/insulating film. CONSTITUTION:Capacitor trench sides 5 of element isolating/insulating films 2 and 3 are of a two layer structure. This design enables the prevention of the edges of the element isolating/insulating films 2 and 3 from recession in various treatment processes to follow pattern formation. That is, when etching selection ratios are appropriately chosen for them, a second insulating 3 is not affected but serves as a block in a process wherein a first insulating film 2 is etched, as the result of which the edges of the element isolating/insulating films 3 and 2 can be prevented from recession. When capacitor trenches 51 and 52 are formed in contact with such element isolating/insulating films, the distance between neighboring memory cell capacitor trenches may be reduced to the required minimum. This design produces an enhanced integration DRAM without reduction in reliability. |
