The resistance of patterns is one of important items of circuit characteristics, the printed pattern resistance changes depending on the printing conditions in the roll-to-roll continuous printing system. Also, for dense circuit design, the result of the spread ratio, which is the ratio of the line width to the line width of the designed line, is also important.

To optimize printing conditions, minimizing pattern resistance and spread ratio 100 %, in this study the drying temperature, wind speed, and linear velocity of printing are selected as effective factors to the objectives. Then experimental design method is used to minimize the number of experiments and to obtain optimum condition. Finally the prediction results produced from the optimum condition were verified by the reproducibility test.

As a raw material, PG-007 Silver nano ink, and SKC PET film is used as conductive silver ink and web film, respectively. The printing result is a pattern line having a width of 500 ㎛ and a length of 80 mm. The resistance is measured with a multimeter, pattern line width and height are measured with ITPlus and 3D surface profiler, then it is analyzed by MATLAB Image Processing according to the international standard (IEC 62899-402-1) method. As a result of pretest, factors & levels for main experiment are decided to establish the main experimental conditions by factorial design method.

The effective factors that minimize the resistance value are printing speed, wind speed, temperature, and ink viscosity in order. The differences in the influence on the spread ratio are the printing velocity, ink viscosity, and, temperature, and wind speed in order. This result is analyzed from the ANCOVA & ANOVA. Based on the ANOVA result, using response optimizer of 100 % spread ratio & minimized resistance the optimum condition is selected that drying temperature 160 ℃, wind speed 40 Hz, printing velocity 15 mm/s, ink viscosity 30000 cP. Those optimum conditions for gaining objectives of this thesis predicts the results of 42.09 Ω resistance and of 100.15 % spread ratio.
In the result of reproducibility test for verifying the prediction value from the optimum conditions, the resistance mean data comes out 41.35 Ω and every data marks within ?2.6 % from the prediction value. The resistance trend line has 0.02 of slope and 0.28 % of probability of error. The spread ratio mean data comes out 103.79 % and every data marks within +6.75 % from the prediction value. The spread ratio trend line has 0.06 of slope and 0.69 % of probability of error.

Overall Capability Ppk of resistance & spread ratio data is 8.27 and 3.82, respectively. However, the result value of 2.11 at Z-bench analysis of spread ratio shows that more manufacturing factors affecting to spread ratio are necessary to be found for stabilizing the long term manufacturing.