30nm half-pitch metal patterning using Motif (TM) CD shrink technique and double patterning - art. no. 69242C

Double patterning lithography appears a likely candidate to bridge the gap between water-based immersion lithography and EUV. A double patterning process is discussed for 30nm half-pitch interconnect structures, using 1.2 NA immersion lithography combined with the Motif (TM) CD shrink technique. An adjusted OPC calculation is required to model the proximity effects of the Motif shrink technique and subsequent metal hard mask (MHM) etch, on top of the lithography based proximity effects. The litho-etch-litho-etch approach is selected to pattern a TiN metal hard mask. This mask is then used to etch the low-k dielectric. The various process steps and challenges encountered are discussed, with the feasibility of this approach demonstrated by successfully transferring a 30nm half-pitch pattern into the MHM