The present disclosure relates to an integrated chip structure having a first copper pillar disposed over a metal pad of an interposer substrate. The first copper pillar has a sidewall defining a recess. A nickel layer is disposed over the first copper pillar and a solder layer is disposed over the first copper pillar and the nickel layer. The solder layer continuously extends from directly over the first copper pillar to within the recess. A second copper layer is disposed between the solder layer and a second substrate.