An integrated circuit package stacking system includes: forming a flexible substrate by: providing an insulating material, forming a stacking pad on the insulating material, forming a coupling pad on the insulating material, and forming a trace between the stacking pad and the coupling pad; providing a package substrate; coupling an integrated circuit to the package substrate; and applying a conductive adhesive on the package substrate for positioning the flexible substrate over the integrated circuit and coupling the flexible substrate on the conductive adhesive.