Study on the influence of pyrithione isomers on filling blind holes in electroplated copper
The study focused on the isomers 2-mercaptopyridine(2-MP)and 4-mercaptopyridine(4-MP),comparing their performance as levelers in filling blind holes.Copper plating experiments in a Hull cell initially investigated the blind hole filling capabilities of 2-MP and 4-MP.The results indicated superior performance by 2-MP,achieving a filling rate of up to 82％.Quantum chemical calculations later revealed a lower electron cloud density of the sulfur atom in the 2-MP molecule than in 4-MP.This suggests a higher likelihood of 2-MP adsorbing onto the copper surface.Chronopotentiometric measurements showed that Cl-can promote the adsorption of 2-MP on the copper surface.Furthermore,the interaction between 2-MP and PEG was significantly stronger than that of 4-MP.X-ray photoelectron spectroscopy(XPS)detected the existence of Cu-S bonds in the final stage,proving chemical adsorption of both levelers onto the copper surface.Nevertheless,the proximity of the mercapto S atom and N atom in the 2-MP molecule allows for the formation of a S-Cu2+-N complex.This complex,in combination with Cl-and PEG,creates a complex and dense inhibition layer.This layer strongly suppresses surface copper deposition,thereby enhancing the blind hole filling rate of 2-MP.
万方数据
维普
