High performance plastic molded QFN package with ribbon bonding and a defective PCB ground

An interconnect transition within the plastic mold is formed between the output ports of the IC sitting on top of a Quad Flat Non-leaded (QFN) package and the nearby I/O leads of the package. This paper describes the design and development of a cost-effective interconnect transition structure for improving the operating frequency of the package up to millimeter-wave range. In addition to adopting ribbon bonds, which have been shown to exhibit a lower insertion loss, a novel Defective Ground Structure (DGS) has been used to compensate the ribbon bond´s imaginary part of impedance (the parasitic capacitive from the I/O pad), thus, achieving superior bandwidth performance. By employing the ribbon bonds and the DGS structures; the measured results of QFN package is able to achieve S₂₁ at -1.5dB up to 62.3 GHz, and S₁₁ less than -10 dB up to 66 GHz.