Design and RF Characterization of Manufacturable Flip-Chip Transition Targeting D-band

In this work an easy to fabricate flip-chip (FC) transition for guiding frequencies in the range from 20 MHz up to 170 GHz is proposed. This transition can be used for chip level packaging in the communication sector for future 6G applications (D-band: 110 GHz to 170 GHz). The technology supports the connection of different chip technologies to combine their benefits in heterointegration. With this a stack-up combining common technologies like CMOS or BiCMOS for signal processing with the high frequency part fabricated in III-V semiconductor technologies can be build. As transition topology a GSG bump guiding structure is employed and investigated. First test chips were fabricated and measured in the base band of the vector network analyzer (VNA) from 20 MHz up to 67 GHz. With this chips an insertion loss (IL) of less than −0.73 dB up to 50 GHz and −2.7 dB at the end of the band for a single transition could be shown. In the next step the design was optimized in electromagnetic (EM) field simulations to increase the performance up to 170 GHz. The estimated IL calculated out of the simulation results show values less than −1.47 dB over the complete frequency range investigated and values less than −0.53 dB up to 150 GHz.