Characterization of Differential TMV Vertical Interconnects to 50GHz with Double Side Measurement

Fan-Out Wafer Level Packaging (FOWLP) can be a good candidate for heterogeneous integration of Photonic ICs (PIC) and Electronic ICs (EIC) in the same package to achieve low interconnect loss, low power consumption, and small factor for optical communications requiring high data transmission. The vertical interconnects Through Mold Via (TMV) in FOWLP can be utilized for the RF routing from frontside to backside vertically. The conventional way of characterizing the RF performance of vertical interconnects is to de-embed the vertical section by measuring a back-to-back structure with multiple de-embedding structures. In this paper, differential TMV structures in GSSG configuration are characterized by direct measurement using double-side probing techniques from DC to 50GHz. Three GSSG TMV interconnects with different TMV pitches are measured and compared. The 100Gbps PAM4 eye diagrams of the interconnects are also shown.