Developing of copper plating bath

ABSTRACT Plating bath solution concentration is one of the important factors in terms of the effect on plating quality. This concentration is tried to remain steady by using a process which includes the flow analysis. In the metal plating process, the concentration of bath solution decreases with the process of plating. To prevent this decreasing a system is developed in which bath solution is reached to the spectrofotometer by the flow analysis technique. Thus the metal concentration is always remained under control. When the metal concentration begin to reduce the dose pump adds sufficient amount of stock solution to the bath. The dose pump is under control of a comparing circuit which senses the signal of spectrofotometer. Solution concentration, the distance between the electrodes, bath temperature and the current density parameters are changed to determine the quality of solution which then will be added to the acidic Copper plating bath. The reducing curves between concentration and time are graphed with the obtained data. The approximate amount of added solution volume is manually given to the bath and the some procedures are repeated. Thus the optimum study conditions are defined. Then the plating is made as an online study with the comparing circuit. As a result, the concentration of plating bath solution is remained in the limit of desired value due to the online working system. Keywords : Flow analysis, online, copper, plating