Full-wave RF Modeling of a Fan-Out Wafer-Level Packaging Technology Based on Al-Al Wafer Bonding

The transmission loss of a test structure, composed of a series of 18 CPW-based interconnections in between a High-Resistive Silicon (HRSi) interposer and a SiGe BiCMOS, produced by using the Al-Al bonding technology for FOWLP is discussed this paper. Its effectiveness as an alternative for mm-wave packaging platforms is proven by an overall S21 below 8 dB (<; 0.2 dB/transition). Together with the experimental outcomes, the rigorous full-wave modeling of the configuration under investigation is also presented. Particular emphasis is placed on the chosen approach for addressing the criticalities that arise when it comes to simulate structures presenting different scales in their geometry. The validity of the model has been tested against the measured S-parameters, and a good accordance between the latter and the simulated results has been found, which makes the developed numerical platform a reliable tool for further optimization of the next generation of Al-Al FOWLP technology-based devices.