Quick development of copper electroplating formula for via and trench filling by an experiential method

An experimental method is introduced for quickly developing a new copper electroplating formula of via and trench filling. The total potential drop (∆η) after leveler added into electroplating solution in galvanostatic measurements (GM), charring area of latten in Hull cell electroplating and via filling dimple in Harring cell electroplating were sequentially employed to evaluate and screen the leveler for copper electroplating via and trench filling. Three levelers synthesized by imidazole and different concentration of 1,4-butanediol diglycidyl ether were used to demonstrate the availability of suggested experimental method. The results indicate that the leveler orderly screened by GM, hull cell electroplating and Harring cell electroplating shows an excellent performance of improving via filling. Then, the air agitation and concentration of other components in electroplating solution were further optimized for via and trench filling. In harring cell, in the condition of 1.5 A/dm2 current density, the via with 100 μm diameter and 80 μm depth was filled with dimple < 10 μm after 45 min, the silicon trench with 25 μm width and 115 μm depth was filled after 80 min. This experimental method is helpful for researchers to develop a qualified copper electroplating formula for electronic manufacture.