Design of Experiments for Reduce Cycle Time of Plasma Cleaning on Surface of Flexible Printed Circuits

Abstract

Flexible Printed Circuits (FPC) are important components for various electronic devices. Currently, customer demand tends to increase over time. For this reason, the company must increase output capacity to meet the needs of customers. FPCs are applied low-pressure plasma process in order to control the quality to be clean and enhance connectivity in electronic devices. The objectives are to increase output capacity by reducing the cycle time and to identify the effect of low-pressure plasma cleaning parameters on the Water Contact angle (WCA). It must not exceed 30degrees, which is in accordance with customer requirements. According to relevant researches, the factors affecting the optimizing of plasma parameters were plasma time, the power of the radio frequency, the flow rate of oxygen and the flow rate of argon. A central composite design was applied to design the experiments and response surface methodology was applied to analyze the experiments.  The results revealed that the optimal parameters were a plasma time of 6.37 min, power of 4.20 kW, an oxygen flow rate of 0.10 l/min and an argon gas flow rate of 0.60 l/min. The average water contact angle does not exceed 10.357 degrees at a 95 percent confidence level. In addition, the plasma processing time was reduced from 16 minutes to 6.37 minutes, resulting in a 52.97 percent increase in plasma processing capacity.