A method of depositing one or more stiffener onto a wiring board includes the steps of engaging the wiring board onto a heat-retaining pallet to form an assembly, pre-heating the assembly to a temperature ranged from 70 to 140° C., and disposing the stiffeners onto the pre-heated wiring board of the assembly, wherein the pallet of the assembly retains sufficient heat for the wiring board to at least partially melt the stiffener, more preferably adhesive stiffener, to fix onto the wiring board upon disposition of the stiffeners.