Semiconductor device and method for fabricating the same

Abstract

A semiconductor device includes: a semiconductor substrate; a plurality of bit line structures spaced apart from each other over the semiconductor substrate and each including a stacked structure of a bit line and a bit line hard mask; a contact pad positioned over the semiconductor substrate between the neighboring bit line structures; a contact structure including a stacked structure of a first contact formed over the contact pad and a second contact having a greater line width than the first contact; a first spacer structure interposed between the first contact and each of the bit line structures; and a second spacer structure interposed between the second contact and each of the bit line structures and having a smaller dielectric constant than the first spacer structure.