This paper proposes shift-trim double patterning lithography (ST-DPL), a cost-effective method for achieving 2× pitchrelaxation
with a single photomask (especially at polysilicon layer). The mask is re-used for the second exposure by
applying a translational mask-shift. Extra printed features are then removed using a non-critical trim exposure. The
viability of ST-DPL is demonstrated. The proposed method has many advantages with virtually no area overhead (< 0.3%
standard-cell area): (1) cuts mask-cost to nearly half that of standard-DPL, (2) reduces overlay errors between the two
patterns and can virtually eliminate it in some process implementations, (3) alleviates the bimodal problem in doublepatterning,
and (4) enhances throughput of first-rate scanners. We implement a small 45nm standard-cell library and small
benchmark designs with ST-DPL to illustrate its viability.