A method and apparatus is provided for testing integrated circuits and permanently affixing the ICs which are successfully tested to a product level carrier substrate. A modular test oven is used which allows the chips to be electrically and thermally tested with the chips non-permanently affixed to a carrier substrate. If all of the chips on the carrier substrate test good, then the temperature within the oven is elevated, thereby reflowing the solder balls and permanently affixing the chips to the carrier substrate. This card can then be used in the manufacture of an electronic device without the necessity of reworking the burned-in ICs. Further, if any of the chips fail the burn-in testing, the time and overhead required for reworking is minimized since the chips are not permanently attached.