Method for fabricating DRAM device

摘要

A method for fabricating a DRAM device, comprising the steps of: providing a SOI substrate upon which a first silicon layer, a buried oxide film and a second silicon layer are stacked; forming an isolation film in the second silicon layer; forming first and second trenches in the second silicon layer and the isolation film; forming gate electrodes in both sidewalls of the first and second trenches; forming first and second impurity regions in the upper surface of both sides of the first trenches and third and fourth impurity regions beneath the first and second trenches by injecting impurity ions into the second silicon layer; forming a capacitor to contact the first and the second impurity regions via first and second contact holes in a first intermediate insulating layer, and a first wiring to contact with the fourth impurity region via third contact hole in the first insulating layer; forming a first conductive layer pattern including a second wiring to contact with the first wiring via fourth contact hole on a second first intermediate insulating layer; bonding a dummy substrate to a third intermediate insulating layer; removing the first silicon layer; forming a bit line and a third wiring connected to third and the fourth impurity regions via fifth and sixth contact holes in the buried oxide film; and forming a second conductive layer pattern including a fourth wiring to contact with the third wiring via seventh contact hole on a fourth intermediate layer.