A method for fabricating a semiconductor device includes: providing a substrate structure including a bit line and a capacitor formed apart from each other at a different level; forming first, second, and third insulation layers over the bit line, the second insulation layer being a first etch stop layer; forming a second etch stop layer over a top electrode of the capacitor; forming a fourth insulation layer over the third insulation layer and the second etch stop layer; and performing a plurality of etch steps to expose an upper surface of the bit line and an upper surface of the capacitor.