Novel LTCC/BGA modules for highly integrated millimeter-wave transceivers

Advanced packaging concepts for highly integrated encapsulated millimeter-wave modules are demonstrated. Millimeter-wave monolithic integrated circuits (MMICs) are flip-chip mounted on top of a low-temperature co-fired ceramic (LTCC) package. This type of "smart package" can integrate various passive functions as well as compact interconnections between MMIC and vertical feedthroughs. The bottom side of this package is connected via a standard ball grid array (BGA) to a low-cost laminate printed circuit board serving as a motherboard for multiple LTCC modules. Fabricated passive LTCC test structures fully validate the approach for millimeter-wave applications. LTCC-/BGA-based packages feature good performance up to approximately 30 GHz. Alternatively to BGA technology, anisotropic conductive pastes are applied as well. They have proven to be suitable at least up to 40 GHz.