Bottom-up filling of TSV-scaled trenches by using step current electrodeposition

Void-free filling of TSV-scaled trenches is achieved by adding a new leveler with an accelerator and polymeric suppressor. Leveler containing two quaternary ammonium salts allows for the galvanostatic bottom-up filling. In addition, the filling time is reduced by applying the step current comprising a first step to establish a growing surface and a second step to reduce the filling time. The deposition height of the growing surface during the first step critically determines the filling performance. By modulating the step condition, the filling time reduced by 47% compared to the constant current deposition.