Transient Closed-Loop Heating for Localized MEMS Bonding

We achieve practical closed-loop control of a microfabricated resistive heating trace in millisecond-scale transient regimes for MEMS local solder bonding. This is one or two orders of magnitude faster than previous implementations and may be competitive with laser assisted bonding. We also present simple theoretical models for analyzing these heaters, then identify and analyze a possible failure mode due to local thermal fluctuations in more complex heater traces. Together, these represent significant progress toward making resistive localized bonding for general packaging purposes practically feasible.