US Patent 9048222 Method of fabricating interconnect structure for package-on-package devices

An interconnect structure and a method of forming an interconnect structure are provided. The interconnect structure is formed over a carrier substrate, upon which a die may also be attached. Upon removal of the carrier substrate and singulation, a first package is formed. A second package may be attached to the first package, wherein the second package may be electrically coupled to through vias formed in the first package.