Information is presented regarding a newly developed bottom package of a package on package (PoP) structure referred to as a dual face package (DFP). Two types of DFP have been developed; one is DFP-PO (POst type), and the other is DFP-PW (Post with Wire component type). 116 PoPs were experimentally produced using DFP-PO. The assembly yield was 100% and there were no failures in a 500 thermocycle PoP test. There was no failure of the DFP-PW under thermocycle testing of a single package over 150 cycles. The DFP-PW was assembled using a post with wire component (PWC), newly developed by Kyushu Institute of Technology and a cooperative enterprise. Using this PWC, compact and thin DFP were achieved, in comparison with the current bottom package of PoP. The PWC contributes a compact and simple JISSO package for the semiconductor field besides PoP such as embedded IC substrates, image sensor packages and wafer level chip size packages (WLCSP).