A method of assembling Redistributed Chip Package (RCP) semiconductor devices. An active die structure is encapsulated in a molding compound with internal electrical contacts of the active die structure positioned at an active face of an encapsulation layer. A dummy die structure is positioned at a back face of the encapsulation layer. A redistribution layer is formed at an active face of the encapsulation layer. The redistribution layer includes a layer of insulating material and redistribution electrical interconnections. The insulating material is built up with grooves along saw streets. External electrical contacts exposed at a surface of the redistribution layer are connected with the redistribution electrical interconnections. The dummy die structure is removed and then the semiconductor devices are singulated.