Heterogeneous Flip-Chip Assembly of a GaAs C-band Power Amplifier MMIC Using Liquid Metal Vertical Interconnects

A new process utilizing room temperature liquid metals as interconnect material for flip chip assembly of active circuits has been demonstrated. These interconnects form flexible bonds between chips of heterogeneous materials and therefore flip clip assembly built with this configuration is not susceptible to thermomechanical stresses. A prefabricated GaAs MMIC chip is post processed to integrate liquid metal assembly structures. For the operation frequency of the MMIC between 4.9 - 8.5 GHz, average gain of the assembly is greater than 20 dB with an average transition loss of less than 1.8 dB.