US Patent 9230858 Semiconductor device and method for manufacturing the same

A semiconductor device is manufactured by etching a semiconductor substrate including an active region, forming a bit line contact hole from which the active region is protruded, forming a first spacer exposing a top of the active region at each of an inner wall and a bottom of the bit line contact hole, forming a bit line contact plug and a bit line over the exposed active region, and forming a second spacer over the semiconductor substrate including not only the bit line contact plug but also the bit line.