Method for fabricating memory device with buried digit lines and buried word lines

Abstract

A method for fabricating a memory array includes providing a semiconductor substrate having thereon a plurality of line-shaped active areas and intermittent line-shaped trench isolation regions between the plurality of line-shaped active areas, which extend along a first direction; forming buried word lines extending along a second direction in the semiconductor substrate, the buried word lines intersecting with the line-shaped active areas and the intermittent line-shaped trench isolation regions, wherein the second direction is not perpendicular to the first direction; forming buried digit lines extending along a third direction in the semiconductor substrate, wherein the third direction is substantially perpendicular to the second direction; and forming storage nodes at storage node sites between the buried digit lines.