Flip-Chip Interconnect for Coplanar Strip Lines

A flip-chip interconnect configuration with coplanar strip (CPS) lines on printed circuit boards (PCBs) is reported for millimeter-wave applications. For CPS lines, the signal and ground electrodes both lie on the top surface of a chip or substrate. The flip-chip configuration was designed and implemented using a test chip on a dielectric board. Geometrical parameter analysis was carried out using full-wave simulation and equivalent circuit model for wideband performance. The chip was connected to the board using solder bumps. For a typical flip-chip assembly, the measured insertion loss is less than $3dB$ for frequencies of up to $35GHz$ and the return loss is higher than $15dB$ for frequencies of up to $29GHz$ using CPS flip-chip configuration.