Air Bridge Based Planar Hybrid Technology for Microwave and Millimeterwave Applications

A new silicon based, planar hybrid technology is being developed to address limitations associated with packaging and interconnections. The approach combines the advantages of both hybrid and monolithic technologies. Microwave transistor chips (e.g. GaAs FETs) are glued with an epoxy resin in openings micromachined in a high resistivity silicon substrate with a vertical precision of better than 2 μm and lateral tolerances less than 10 μm. Air bridge technology and thin film techniques are then used to provide the necessary interconnections. Preliminary results show very promising high frequency properties of this assembly.