An overlay interconnect technology for 1 GHz and above MCMs

An overlay interconnect technology is presented that is suitable for 1 GHz and above operation of GaAs and Si multichip module (MCM) circuits. This technology encompasses a back side bonded, chips first approach with an adaptive laser photolithography defined multilayer overlay interconnect providing consistent line impedances with low crosstalk and signal delay. Signal propagation velocities of 18 cm/ns have been demonstrated on lines with an insertion loss of 0.25 dB/cm at 10 GHz. This interconnect system has been used to interconnect GaAs digital circuits operating at clock frequencies of 2.0 GHz without power supply bypass capacitors