A solder-free interconnect approach for integrating millimeter wave high-power devices with planar circuitry

The development of commercial millimeter wave systems requires cost-effective, high-performance device/circuit assembly techniques. A solder-free thermosonic bonding approach is described here to integrate millimeter wave high-power devices with associated planar circuitry. The devices with integrated heatsink are attached to a metal block, and then ribbon bonded with planar millimeter-wave transmission line circuitry using the developed solderfree thermosonic bonding process. The assembly process is designed to minimize the stresses that damage the devices, while maintaining the bond integrity. Observations confirm that the introduction of ultrasonic energy into the bonding process significantly reduces the temperature and assembly force applied to the device. The effects of different assembly parameters on the performance of the device are also presented.