Fabrication of contact/via holes for 32-nm technology device using cost-effective RIE CD shrink process and double patterning technique

We have developed a cost-effective critical dimension (CD) shrink technique that allows all-in-one processing of CD shrinking, BARC etching, hard mask etching, and resist stripping in a reactive ion etcher (RIE) for the double patterning (DP) required in the formation of contact and via hole masks with the most critical exposure margins. This CD shrink technique was successfully applied to achieve a CD shrinkage of 60 nm and a CD uniformity of within 3 nm at 3 sigma over the wafer surface. We also determined that the CD shrink technique that employs RIE differs from CD shrink by resolution enhancement lithography assisted by chemical shrink (RELACS) [1] and low-temperature molecular layer deposition (MLD) in having an effect of expanding the lithography process window. We successfully applied our technique to form a 30-nm CD hole pattern with a duty ratio of 1:1.