Low-Cost High-Bandwidth Millimeter Wave Leadframe Packages

As integrated circuit speeds and bandwidth needs increase, low-cost packaging and interconnect technology continue to be challenges. Solutions to these problems are driven by consumers’ desire for increasing bandwidth (e.g., portable communications applications) and manufacturers’ desire to drive down system cost (e.g., taking advantage of volume manufacturing processes). This work describes a low-cost plastic QFN package possible of meeting these needs. This package has low-loss, high-bandwidth and is based around microCoax interconnect technology. Since this package structure is broadband, it allows for a variety of chipsets to be assembled using the same process sequence and I/O configuration, thereby eliminating costly overhead. With less than 0.5 dB insertion-loss and >15 dB return-loss per RF interconnect at 50 GHz, a 5×5 mm microCoax QFN package allows existing bare-die only applications to enter the world of high-speed PCB assembly, significantly driving down the cost of high-frequency RF subsystems. Process technology, I/O performance, active device performance, PCB board material selection and test protocol will all be discussed.