Abstract: A semiconductor structure includes a functional die, a dummy die, a redistribution structure, a seal ring and an alignment mark. The dummy die is electrically isolated from the functional die. The redistribution structure is disposed over and electrically connected to the functional die. The seal ring is disposed over the dummy die. The alignment mark is between the seal ring and the redistribution structure, wherein the alignment mark is electrically isolated from the dummy die, the redistribution structure and the seal ring. The insulating layer encapsulates the functional die and the dummy die.

Abstract: A method of inhibiting a formation of palladium-nickel-tin (Pd—Ni—Sn) intermetallic in solder joints is described as follows. Firstly, a solder alloy is provided. Then, at least one of a trace of copper and a trace of zinc is doped into the solder alloy. Afterward, the solder alloy is disposed on the Pd-bearing surface finish, such as a Pd/Ni bi-layer or a Au/Pd/Ni tri-layer. Next, the solder alloy is soldered with the surface finish as solder joints. During the soldering, the Cu and Zn will incorporate into the soldering reaction, forming copper-palladium-nickel-tin intermetallic and zinc-palladium-nickel-tin intermetallic, replacing the Pd—Ni—Sn respectively. Consequently, the addition of Cu and/or Zn into solders will inhibit the undesirable Pd—Ni—Sn intermetallic to form in the solder joints.