Rapid and Selective Induction Heating for Sensor Packaging

A novel hermetic packaging for sensors using induction heating was presented in this paper. By choosing suitable frequency of high frequency power supply and optimizing the induction coil, rapid and selective induction heating for hermetic packaging has been achieved in several seconds. Because only the local areas (including the cap, metal loop and solder ring) were effectively heated to a predetermined temperature to melt the solder, while the ceramic package and the chip cannot be effectively heated because no eddy current or little eddy current was inducted and maintained at low temperature, therefore thermal damages to temperature-sensitive chip or circuits can be avoided. The new technique can be applied to hermetic packaging for sensors with high yield.