Semiconductor device with air gap and method for fabricating the same

Abstract

A method for fabricating a semiconductor device includes: forming a plurality of bit line structures over a semiconductor substrate; forming a line-type opening between the bit line structures; forming a sacrificial spacer on both sidewalls of the line-type opening; forming a line-type plug filling the line-type opening over the sacrificial spacer; forming a plurality of plug isolation openings that expose the sacrificial spacer by etching a portion of the line-type plug in a direction crossing the bit line structures; forming a plurality of air gaps by removing the exposed sacrificial spacer; removing a remaining line-type plug below the plug isolation openings to form a plurality of island-type plugs; and forming a plug isolation layer inside the plug isolation openings to isolate neighboring island-type plugs from each other.

Dependencies are inferred from the claim text.