Abstract: A wafer level package mainly comprises a semiconductor wafer and a plurality of bonding pads disposed on the active surface of the wafer. It is characterized in that there is a protection layer formed on the back surface of the wafer, wherein the wettability of the solder material with the protection layer is lower than the wettability of the solder material with the bonding pads. In such a manner, the protection layer will prevent the back surface of the wafer from being contaminated with the solder material. Moreover, when a UBM layer is further provided on the bonding pad, the wettability of the solder material with the protection layer is lower than the wettability of the solder material with the UBM layer.

Abstract: A circuit structure of a redistribution layer (RDL) is suitable for a chip to define the circuits and the contact window required by the following bump process. The RDL is disposed on the active surface of the chip. The circuit structure of the RDL mainly includes a first titanium layer, a second titanium layer and a conductive layer. Wherein, the conductive layer is made of aluminum; the first titanium layer and the second titanium layer cover the two surfaces of the conductive layer, respectively. The connectivity between the first titanium layer or the second titanium layer and a macromolecule polymer is stronger than the connectivity between the conductive layer and the macromolecule polymer, so that the peeling or crack caused by poor connectivity between the conductive layer and the adjacent dielectric layers are significantly improved thereby.

Abstract: A wafer level package mainly comprises a semiconductor wafer and a plurality of bonding pads disposed on the active surface of the wafer. It is characterized in that there is a protection layer formed on the back surface of the wafer, wherein the wettability of the solder material with the protection layer is lower than the wettability of the solder material with the bonding pads. In such a manner, the protection layer will prevent the back surface of the wafer from being contaminated with the solder material. Moreover, when a UBM layer is further provided on the bonding pad, the wettability of the solder material with the protection layer is lower than the wettability of the solder material with the UBM layer.