preparing a printed circuit board (PCB) strip having a first surface and a second surface, the PCB strip comprising a plurality of individual PCBs electrically isolated from one another;

stacking a plurality of first semiconductor chips and forming an encapsulant on a first surface of a first individual PCB of the plurality of individual PCBs to form a first semiconductor chip stack structure comprising a first semiconductor chip stack corresponding to the first individual PCB;

performing a first test adapted to test one of the first semiconductor chips in the first semiconductor chip stack;

flip chip bonding a second semiconductor chip to a second surface of the first individual PCB if the first semiconductor chip stack meets a test standard based on a result of the first test;

performing a second test adapted to test the second semiconductor chip; and,

dividing the first semiconductor chip stack structure to form a system in package after selectively flip chip bonding the second semiconductor chip to the second surface of the first individual PCB.