The Double Patterning (DP) process is mainly for the resolution enhancement beyond limited lithography system not only high Numerical Aperture (NA) system but small one also. In this paper, we developed several duty patterns using DP technology under ArF, 0.75 NA systems to meet the 65nm half-pitch patterns. For the line DP process, it is clear that the limited resolution is 65nm half pitch pattern with marginal process windows and overlay should be controlled within 30nm, M+3σ value. For the 2 nd patterning process, there is dose shift compared with 1 st patterning dose for the substrate difference.From these results, DP technologies can be applied to overcome resolution limited process not only fine patterning required but certain patterning which can be achieved without any investments.