Patent ID: 8900968

Claim:
A method for manufacturing a semiconductor device comprising: forming a first film over a semiconductor substrate; forming a second film over the first film; patterning the first and second films; forming a device isolation groove using the first and second films as a mask to define a first to fourth device formation portions in the semiconductor substrate; forming a third film in the device isolation groove and over the second film; removing a part of the third film so that the third film remains in a bottom of the device isolation groove; forming a fourth film over the third film; removing the first film, second film and an upper portion of the fourth film so that the device isolation groove is filled with the fourth film; forming a plurality of gate electrode trenches in the semiconductor substrate so that the plurality of gate electrode trenches cross over the third and fourth device formation portions; and forming a plurality of buried wires by filling the plurality of gate electrode trenches with a conductive material, wherein the second device formation portion faces to the first device formation portion, the third device formation portion connects to the first device formation portion in a first direction so that the third device formation portion does not reach the second device formation portion, the fourth device formation portion connects to the second device formation portion in opposite the first direction so that the fourth device formation portion does not reach the first device formation portions, wherein the plurality of gate electrode trenches comprise a first wiring portion, wherein the third and fourth device formation portions are positioned adjacently between the first and second device formation portions, wherein the third and fourth device formation portions have first and second trenches, respectively, and wherein the first wiring portion fills the first and second trenches.