A semiconductor device includes a first circuit layer, a copper pillar disposed adjacent to the first circuit layer, a second circuit layer and a solder layer. The second circuit layer includes an electrical contact and a surface finish layer disposed on the electrical contact, wherein a material of the surface finish layer is a combination of at least two of nickel, gold, and palladium. The solder layer is disposed between the copper pillar and the surface finish layer. The solder layer includes a first intermetallic compound (IMC) and a second IMC, wherein the first IMC includes a combination of two or more of copper, nickel and tin, and the second IMC includes a combination of gold and tin, a combination of palladium and tin, or both.