Patent ID: 8592321

Claim:
A method for fabricating an aperture, comprising: forming a hard mask and a dielectric anti-reflective coating (DARC) on a semiconductor substrate; forming a first bottom anti-reflective coating (BARC) on the DARC; forming a first aperture in the first BARC and portion of the DARC without exposing the hard mask; forming a second BARC on the DARC and filling the first aperture; forming a second aperture in the second BARC and portion of the DARC, wherein the second BARC covering and filled in the first aperture is not removed during the formation of the second aperture, and both a bottom of the first aperture and a bottom of the second aperture are located at the same DARC; and using non-oxygen element containing gas to perform an etching process to transfer the first aperture and the second aperture to the hard mask for forming a plurality of third apertures.