Abstract: A method of forming solder balls on package substrates includes attaching a semiconductor die to a frontside of a package substrate that includes a film over a bottomside of the package substrate including over a plurality of ball land areas configured to receive solder balls thereon, followed by forming an encapsulating mold layer over the semiconductor die. The film blocks contamination such as mold debris from reaching the ball land areas during die attachment and molding. The film is then removed from the bottomside of the package substrate after molding to expose the plurality of exposed ball land areas. Solder balls are dispensed onto the plurality of exposed ball land areas.