Novel Method for Detection of Organic Additives in Copper Plating Baths

Appropriate organic additives, including accelerators, inhibitors and leveling additives, are essential in the copper plating process of printed circuit boards to achieve defect-free filling effect. The fluctuation of organic additives would cause product defects and reduce manufacturing efficiency resulting in increasing additional cost. Therefore, it is very important to control the quality of electroplating. Development of sensors that detect the concentration of organic additives is indispensable. At present, the concentration of organic additives can only be measured by offline sampling in industry. An indirect cyclic voltammetry stripping (CVS) are often used to detect the concentration of organic additives based on the stripping peak of copper. This study attempts to measure the organic additives directly at high applied potential by using three different electrochemical methods, including linear sweep voltammetry (LSV), differential pulse voltammetry (DPV) and square wave voltammetry (SWV). The results show that the response current values of the three electrochemical methods have a good linear relationship with the concentration of the organic additives. The sensitivity of the electrode by LSV is the highest. There are two proper potentials to detect the additives by SWV. However, the detection potentials of the three organic additives are quite close. If these organic additives should be accurately identified separately, the electrode would need to be further modified.