An Iterative Extremely Accurate Generalized Design Methodology for TSV-Based Hybrid AlScN FBAR and IPD Filtering Chips

In this article, a generalized iterative design methodology for hybrid devices based on film bulk acoustic resonators (FBARs) is proposed. The methodology aims to reduce the simulation difficulty and improve the simulation accuracy by gradually considering the internal and mutual coupling and parasitic responses of multitechnology chips through multiple iterations. To verify, a hybrid bandpass filter (BPF) chip working on the N79 band based on FBAR and integrated passive device (IPD) technology with high harmonic rejection is designed and measured according to the methodology. The FBAR chip is based on aluminum nitride (AlN) with 20% scandium (Sc) (Al0.8Sc0.2N) to achieve a high electromechanical coupling coefficient (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k} _{t}^{2}$ </tex-math></inline-formula>). Two parts of the hybrid chip are packaged on the same substrate through flip-chip (FC) bonding. The measured results show an extremely high-performance stopband consistent with the simulated results, which validates the design methodology.