Soldering by Local Heating

Soldering is a process that enables the joint formation between two substrates via metal filler, that is, solder. The process has been a packaging procedure to provide electrical interconnection and mechanical protection for electronic devices. Micro-electro mechanical system (MEMS) devices may have free-standing multilayered structures accompanied with thermal stress issues to affect device’s performances. The local heating process is an effective way to mitigate the stress effect induced by the thermal mismatch at the interfaces of various substrates. The local soldering joints for MEMS packaging can be achieved using radiative, resistive, inductive, and fricative heating schemes by confining the applied energy within the bonding interfaces. Silicon optical bench assembly can be also achieved using the localized resistive heating and soldering method. The inductive heating mechanism has been proposed as an alternative for the realization of localized soldering. Solder reflow resulting from the reactive heating can perfuse a crack in the reacted foil for good bonding.