Method for bonding circuit boards to pallets

摘要

A method of joining a metal heat sink pallet to a circuit board by electroplating a layer of solder on the mounting surface of the pallet, placing and holding the circuit board metal circuit paths firmly against the plated mounting surface of the pallet and heating the pallet until the solder melts and alloys with the circuit paths. A nitrogen gas bath is used to inhibit oxidation during heating and alloying and a flux is used to promote alloying. A bonding fixture accurately positions the circuit board with respect to the pallet and applies pressure in circuit path areas of interest during heating, alloying and cooling to accurately position the circuit board on the pallet and to promote a superior mechanical and electrical bond between the circuit paths and the pallet.