System and method for mounting electronic components onto flexible substrates

A system and method for reflowing solder to interconnect a plurality of electronic components (24) to a substrate (12) is disclosed. The system includes an oven for preheating the substrate (12) and the plurality of electric components (24) disposed thereon, a supplemental heat source disposed in the oven for providing additional heat energy to reflow the solder (72), a pallet (14) for supporting the substrate (12), wherein the pallet (14) has at least one internal cavity (40), and a phase-transition material (42) disposed within the cavity (40) for absorbing heat from the pallet (14).